1.
Homemaking
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Homemaking is a mainly American term for the management of a home, otherwise known as housework, housekeeping, or household management. It is the act of overseeing the organizational, day-to-day operations of a house or estate, and the managing of other domestic concerns. A person in charge of the homemaking, who isnt employed outside the home, is in the U. S. and Canada often called a homemaker, a gender-neutral term for a housewife or a househusband. The term homemaker, however, may refer to a social worker who manages a household during the incapacity of the housewife or househusband. Housework is not always a lifetime commitment, many, for economic or personal reasons, in previous decades, there were many mandatory courses for the young to learn the skills of homemaking. In high school, courses included cooking, nutrition, home economics, family and consumer science and this last one may underlie the tradition that a homemaker is portrayed wearing an apron. More recently, most of these courses have been abolished, and many youths in school and college would be more likely to study child development. The reason for this is that mechanical invention has been applied extensively to different tasks of the home, inventors have developed mechanical labor-saving devices not only for the shop and office, but also for the home. There are, on the market, thousands of tools, devices. It only remains for the homemaker to choose between them, another reason for the great supply and demand for household labor savers in the industrial world is that the homemaker has to face the increasingly complex problem of scarce domestic help. With cheap labor, the need for the mechanical replacers of labor, or mechanical servants, will not be felt, however. It is to class of homemakers who are actively concerned in domestic work that the labor-saver. The homemakers time and effort are worth conserving by every means, homemakers should, therefore, be eager to buy and use all the household tools that will save their strength and time and liberate them from household drudgery. While some homemakers are handy with tools, the remains that most homemakers are unfamiliar with the different principles involved in mechanical tools. The homemaker, however, is called to have knowledge of the principles of applied mechanics, courses in school physics unfortunately leave a student with little practical knowledge that can be applied to domestic equipment. The gaining of knowledge concerning domestic tools may lead the homemaker to purchase good quality equipment, housekeeping by the homemaker is the care and control of property, ensuring its maintenance and proper use and appearance. A home is a place of residence, in a private home a maid or housekeeper might be employed to do some of the housekeeping. Housework is work done by the act of housekeeping, Some housekeeping is housecleaning and some housekeeping is home chores
2.
Cleaner
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A cleaner is a type of industrial or domestic worker who cleans homes or commercial premises for payment. Cleaners may specialise in cleaning particular things or places, such as window cleaners, cleaners often work when the people who otherwise occupy the space are not around. They may clean offices at night or houses during the workday, the 2000 film Bread and Roses by British director Ken Loach depicted the struggle of cleaners in Los Angeles, California to fight for better pay and working conditions, and the right to join a union. In an interview with the BBC in 2001, Loach stated that thousands of cleaners from around 30 countries have since contacted him with similar to the one told in the film. The cleaning industry is big as there are different types of cleaning required depending on the shape. If you want to get an office space cleaned then you would require the services of a commercial cleaner whereas if you want to clean your house then you would require domestic cleaning services. Depending on the task, even these categories can be sub divided such as Bond cleaners, carpet cleaners, upholstery cleaners, window cleaners, different types of cleaners specialize in their own industry, you cannot ask a window cleaner to do a marvelous job at carpet cleaning. Some of the types of cleaners are mentioned below and these cleaners are quite easy to find due to their large numbers, they are usually denoted as maid service providers, janitors and domestic cleaners. These type of cleaners specialize in house cleaning services such as spring cleaning, most of the house cleaners are known to give good attention to details, but due to their large numbers it can be quite hard to find the right cleaner who is trustworthy and works effectively. The cost of this type of service depends on the demand for the service, in Australia, you can hire a household cleaner from anywhere between $20–$30 an hour. In countries like India, China, Philippines etc. where the rates are quite low
3.
Cooking
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Cooking or cookery is the art, technology and craft of preparing food for consumption with the use of heat. The ways or types of cooking also depend on the skill, cooking is done both by people in their own dwellings and by professional cooks and chefs in restaurants and other food establishments. Cooking can also occur through chemical reactions without the presence of heat, such as in ceviche, preparing food with heat or fire is an activity unique to humans. It may have started around 2 million years ago, though evidence for it reaches no more than 1 million years ago. The expansion of agriculture, commerce, trade and transportation between civilizations in different regions offered cooks many new ingredients, New inventions and technologies, such as the invention of pottery for holding and boiling water, expanded cooking techniques. Some modern cooks apply advanced scientific techniques to food preparation to further enhance the flavor of the dish served, phylogenetic analysis suggests that human ancestors may have invented cooking as far back as 1.8 million to 2.3 million years ago. Re-analysis of burnt bone fragments and plant ashes from the Wonderwerk Cave, there is evidence that Homo erectus was cooking their food as early as 500,000 years ago. Evidence for the use of fire by Homo erectus beginning some 400,000 years ago has wide scholarly support. Archeological evidence, from 300,000 years ago, in the form of ancient hearths, earth ovens, burnt animal bones, and flint, are found across Europe, anthropologists think that widespread cooking fires began about 250,000 years ago, when hearths started appearing. More recently, the earliest hearths have been reported to be at least 790,000 years old, in the seventeenth and eighteenth centuries, food was a classic marker of identity in Europe. In the nineteenth-century Age of Nationalism cuisine became a symbol of national identity. Communication between the Old World and the New World in the Colombian exchange influenced the history of cooking, the Industrial Revolution brought mass-production, mass-marketing and standardization of food. Factories processed, preserved, canned, and packaged a wide variety of foods, in the 1920s, freezing methods, cafeterias and fast-food establishments emerged. Along with changes in food, starting early in the 20th century, governments have issued nutrition guidelines, the 1916 Food For Young Children became the first USDA guide to give specific dietary guidelines. Updated in the 1920s, these guides gave shopping suggestions for different-sized families along with a Depression Era revision which included four cost levels, in 1943, the USDA created the Basic Seven chart to make sure that people got the recommended nutrients. It included the first-ever Recommended Daily Allowances from the National Academy of Sciences, in 1956, the Essentials of an Adequate Diet brought recommendations which cut the number of groups that American school children would learn about down to four. In 1979, a guide called Food addressed the link between too much of certain foods and chronic diseases, but added fats, oils, most ingredients in cooking are derived from living organisms. Vegetables, fruits, grains and nuts as well as herbs and spices come from plants, while meat, eggs, mushrooms and the yeast used in baking are kinds of fungi
4.
Shopping
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A retailer or a shop is a business that presents a selection of goods and offers to trade or sell them to customers for money or other goods. Shopping is an activity in which a customer browses the available goods or services presented by one or more retailers with the intent to purchase a selection of them. In some contexts it may be considered an activity as well as an economic one. The B2C process has made it easy for consumers to select any product online from a website and have it delivered to the consumer within no time. The consumer does not need to consume his energy by going out to the stores and saves his time and cost of travelling. The shopping experience can range from delightful to terrible, based on a variety of factors including how the customer is treated, convenience, the type of goods being purchased, the shopping experience can also be influenced by other shoppers. According to a 2000 report, in the U. S. state of New York, women purchase 80% of all consumer goods, in ancient Greece, the agora served as a marketplace where merchants kept stalls or shops to sell their goods. Ancient Rome utilized a similar marketplace known as the forum, for example, there was Trajans Market with tabernae that served as retailing units. Shopping lists are known to have used by Romans, as one was discovered near Hadrians wall dated back to 75–125 CE written for a soldier. Fairs and markets were established to facilitate the exchange of goods, people would shop for goods at a weekly market in nearby towns. The modern phenomenon of shopping is closely linked to the emergence of the society in the 18th century. Over the course of the two centuries from 1600 onwards, the power of the average Englishman steadily rose. Sugar consumption doubled in the first half of the 18th century, marketplaces dating back to the Middle Ages, expanded as shopping centres, such as the New Exchange, opened in 1609 by Robert Cecil in the Strand. Shops started to become important as places for Londoners to meet and socialise, restoration London also saw the growth of luxury buildings as advertisements for social position with speculative architects like Nicholas Barbon and Lionel Cranfield. Much pamphleteering of the time was devoted to justifying conspicuous consumption and these trends were vastly accelerated in the 18th century, as rising prosperity and social mobility increased the number of people with disposable income for consumption. The pottery inventor and entrepreneur, Josiah Wedgewood, pioneered the use of marketing techniques to influence, as the century wore on a tremendous variety of goods and manufactures were steadily made available for the urban middle and upper classes. This growth in consumption led to the rise of shopping - a proliferation of shops selling particular goods. Specific streets and districts became devoted to retail, including the Strand, the first display windows in shops were installed in the late 18th century in London
5.
Laundry
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Laundry is the washing of clothing and linens. Laundry processes are often done in a reserved for that purpose. An apartment building or student hall of residence may have a laundry facility such as a tvättstuga. A stand-alone business is referred to as a laundrette, the material that is being washed, or has been laundered, is also generally referred to as laundry. Laundry was first done in watercourses, letting the water carry away the materials which could cause stains, laundry is still done this way in some less industrialized areas and rural regions. Agitation helps remove the dirt, so the laundry is often rubbed, twisted, wooden bats or clubs could be used to help with beating the dirt out. These were often called washing beetles or bats and could be used by the waterside on a rock, on a block and they were once common across Europe and were also used by settlers in North America. Similar techniques have also identified in Japan. When no watercourses were available, laundry was done in vats or vessels. Sometimes large metal cauldrons were filled with water and heated over a fire. Wooden or stone scrubbing surfaces set up near a water supply or portable washboards, including corrugated metal ones. A posser could be used to agitate clothes in a tub, once clean, the clothes were wrung out — twisted to remove most of the water. Then they were hung up on poles or clotheslines to air dry, before the advent of the washing machine, laundry was often done in a communal setting. In poor parts of the world today, laundry is still done beside a river or lake, villages across Europe that could afford it built a wash-house. Water was channelled from a stream or spring and fed into a building, such facilities were much more comfortable than washing in a watercourse because the launderers could work standing up instead of on their knees, and were protected from inclement weather. Also, they didnt have to go far, as the facilities were usually at hand in the village or at the edge of a town and these facilities were public and available to all families, and usually used by the entire village. Many of these village wash-houses are still standing, historic structures with no modern purpose. This job was reserved for women, who washed all their familys laundry, washerwomen took in the laundry of others, charging by the piece
6.
Computer data storage
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Computer data storage, often called storage or memory, is a technology consisting of computer components and recording media used to retain digital data. It is a function and fundamental component of computers. The central processing unit of a computer is what manipulates data by performing computations, in practice, almost all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but larger and cheaper options farther away. In the Von Neumann architecture, the CPU consists of two parts, The control unit and the arithmetic logic unit. The former controls the flow of data between the CPU and memory, while the latter performs arithmetic and logical operations on data, without a significant amount of memory, a computer would merely be able to perform fixed operations and immediately output the result. It would have to be reconfigured to change its behavior and this is acceptable for devices such as desk calculators, digital signal processors, and other specialized devices. Von Neumann machines differ in having a memory in which they store their operating instructions, most modern computers are von Neumann machines. A modern digital computer represents data using the numeral system. Text, numbers, pictures, audio, and nearly any form of information can be converted into a string of bits, or binary digits. The most common unit of storage is the byte, equal to 8 bits, a piece of information can be handled by any computer or device whose storage space is large enough to accommodate the binary representation of the piece of information, or simply data. For example, the works of Shakespeare, about 1250 pages in print. Data is encoded by assigning a bit pattern to each character, digit, by adding bits to each encoded unit, redundancy allows the computer to both detect errors in coded data and correct them based on mathematical algorithms. A random bit flip is typically corrected upon detection, the cyclic redundancy check method is typically used in communications and storage for error detection. A detected error is then retried, data compression methods allow in many cases to represent a string of bits by a shorter bit string and reconstruct the original string when needed. This utilizes substantially less storage for many types of data at the cost of more computation, analysis of trade-off between storage cost saving and costs of related computations and possible delays in data availability is done before deciding whether to keep certain data compressed or not. For security reasons certain types of data may be encrypted in storage to prevent the possibility of unauthorized information reconstruction from chunks of storage snapshots. Generally, the lower a storage is in the hierarchy, the lesser its bandwidth and this traditional division of storage to primary, secondary, tertiary and off-line storage is also guided by cost per bit. In contemporary usage, memory is usually semiconductor storage read-write random-access memory, typically DRAM or other forms of fast but temporary storage
7.
Domestic worker
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A domestic worker or domestic helper or domestic servant is a person who works within the employers household. Other responsibilities may include cooking, laundry and ironing, shopping for food, such work has always needed to be done but before the Industrial Revolution and the advent of labour saving devices, it was physically much harder. Some domestic helpers live within their employers household, in some cases, the contribution and skill of servants whose work encompassed complex management tasks in large households have been highly valued. However, for the most part, domestic work, while necessary, is demanding, although legislation protecting domestic workers is in place in many countries, it is often not extensively enforced. In many jurisdictions, domestic work is regulated and domestic workers are subject to serious abuses. Servant is an older English word for domestic worker, though not all servants worked inside the home, Domestic service, or the employment of people for wages in their employers residence, was sometimes simply called service and has often been part of a hierarchical system. The United Kingdoms Master and Servant Act 1823 was the first of its kind and influenced the creation of domestic laws in other nations. However, before the passing of such Acts servants, and workers in general, had no protection in law, the only real advantage that domestic service provided was the provision of meals, accommodation, and sometimes clothes, in addition to a modest wage. Service was normally an apprentice system with room for advancement through the ranks, the conditions faced by domestic workers have varied considerably throughout history and in the contemporary world. In 2011, the International Labour Organization adopted the Convention Concerning Decent Work for Domestic Workers. In July 2011, at the annual International Labour Conference, held by the ILO, conference delegates adopted the Convention on Domestic Workers by a vote of 396 to 16, the Convention recognized domestic workers as workers with the same rights as other workers. On 26 April 2012, Uruguay was the first country to ratify the convention, many domestic workers are live-in domestics. Though they often have their own quarters, their accommodations are not usually as comfortable as those reserved for the family members, in some cases, they sleep in the kitchen or small rooms, such as a box room, sometimes located in the basement or attic. Domestic workers may live in their own home, though often they are live-in domestics, meaning that they receive their room. The majority of workers in China, Mexico, India. Employers may require their domestic workers to wear a uniform, livery or other domestic workers clothes when in their employers residence, the uniform is usually simple, though aristocratic employers sometimes provided elaborate decorative liveries, especially for use on formal occasions. In traditional portrayals, the attire of domestic workers especially was typically more formal, on 30 March 2009, Peru adopted a law banning employers from requiring domestic workers to wear uniform at public places. However, it’s not explained which punishments will be given to employers violating the law, chile adopted a similar law in 2014, also banning employers to require domestic workers to wear uniform at public places
8.
Mrs Beeton's Book of Household Management
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It had previously been published in parts. It was originally entitled Beetons Book of Household Management, as one of the series of published by her husband. The recipes were highly structured, in contrast to earlier cookbooks and it was illustrated with many monochrome and colour plates. Although Mrs Beeton died in 1865, the continued to be a best-seller. This practice of Mrs Beetons has in modern times repeatedly been described as plagiarism, the book expanded steadily in length, until by 1907 it reached 74 chapters and over 2000 pages. Nearly two million copies were sold by 1868, and it remains in print, between 1875 and 1914 it was probably the most often consulted cookery book. Mrs Beeton has been compared on the strength of the book with modern domestic goddesses like Nigella Lawson, the author, Isabella Beeton, was 21 years old when she started working on the book. It was initially serialised in 24 monthly instalments, in her husband Samuel Orchart Beetons publication The Englishwomans Domestic Magazine, the first instalment appeared in 1859. Etc. —also Sanitary, Medical, & Legal Memoranda, with a History of the Origin, Properties, and Uses of all Things Connected with Home Life and Comfort. In its preface she wrote, I must frankly own, that if I had known, beforehand, that this book would have cost me the labour which it has, I should never have been courageous enough to commence it. What moved me, in the first instance, to attempt a work like this, was the discomfort, I have always thought that there is no more fruitful source of family discontent than a housewifes badly-cooked dinners and untidy ways. Beetons half-sister, Lucy Smiles, was asked about her memories of the books development. She recalled, Different people gave their recipes for the book and that for Baroness pudding was given by the Baroness de Tessier, who lived at Epsom. No recipe went into the book without a trial. I remember Isabella coming out of the one day, This wont do at all, she said. Previously published as a part-work, it was first published as a book in 1861 by S. O. Beeton Publishing,161 Bouverie Street, London, a firm founded by Samuel Beeton. The book was an immediate best-seller, selling 60,000 copies in its first year, in 2010 a copy of the first edition of Household Management in top condition was stated to be worth more than £1,000. In 1863 a revised edition was issued, in 1866, a year after Isabellas death, Samuel was in debt due to the collapse of Overend and Gurney, a London discount house to which he owed money
9.
Municipal solid waste
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Municipal solid waste, commonly known as trash or garbage in the United States and as refuse or rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. Garbage can also specifically to food waste, as in a garbage disposal. The composition of municipal solid waste varies greatly from municipality to municipality, in municipalities which have a well developed waste recycling system, the waste stream consists mainly of intractable wastes such as plastic film, and non-recyclable packaging materials. At the start of the 20th century, the majority of waste in the UK consisted of coal ash from open fires. Most definitions of municipal solid waste do not include industrial wastes, agricultural wastes, medical waste, Waste collection is performed by the municipality within a given area. The term residual waste relates to waste left from household sources containing materials that have not been separated out or sent for reprocessing, the municipal solid waste industry has four components, recycling, composting, disposal, and waste-to-energy via incineration. This location may be a processing facility, a transfer station or a landfill disposal site. Waste handling and separation involves activities associated with waste management until the waste is placed in containers for collection. Handling also encompasses the movement of loaded containers to the point of collection, separating different types of waste components is an important step in the handling and storage of solid waste at the source. The types of means and facilities that are now used for the recovery of materials that have been separated at the source include curbside collection, drop-off. This element involves two main steps, first, the waste is transferred from a smaller collection vehicle to larger transport equipment. The waste is transported, usually over long distances, to a processing or disposal site. In the recent years environmental organizations, such as Freegle or Freecycle Network, have been gaining popularity for their online reuse networks and these networks provide a worldwide online registry of unwanted items that would otherwise be thrown away, for individuals and nonprofits to reuse or recycle. Therefore, this free Internet-based service reduces landfill pollution and promotes the gift economy, landfills are created by land dumping. Land dumping methods vary, most commonly it involves the mass dumping of waste into a designated area, after the waste is dumped, it is then compacted by large machines. When the dumping cell is full, it is sealed with a plastic sheet. This is the method of dumping in the United States because of the low cost. Landfills pose the threat of pollution, and can intoxicate ground water, the signs of pollution are effectively masked by disposal companies and it is often hard to see any evidence
10.
Vacuum cleaner
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The dirt is collected by either a dustbag or a cyclone for later disposal. Specialized shop vacuums can be used to suck up both dust and liquids, although vacuum cleaner and the short form vacuum are neutral names, in some countries hoover is used instead as a genericized trademark, and as a verb. The name comes from the Hoover Company, one of the first, the device is also sometimes called a sweeper although the same term also refers to a carpet sweeper, a similar invention. The vacuum cleaner evolved from the carpet sweeper via manual vacuum cleaners, the first manual models, using bellows, were developed in the 1860s, and the first motorized designs appeared at the turn of the 20th century, with the first decade being the boom decade. In 1860 a carpet sweeper was invented by Daniel Hess of West Union, Iowa that gathered dust with a rotating brush, another early model was the Whirlwind, invented in Chicago in 1868 by Ives W. McGaffey. The bulky device worked with a belt driven fan cranked by hand that made it awkward to operate, a similar model was constructed by Melville R. Bissell of Grand Rapids, Michigan in 1876. The company later added portable vacuum cleaners to its line of cleaning tools, the end of the 19th century saw the introduction of powered cleaners, although early types used some variation of blowing air to clean instead of suction. One appeared in 1898 when John S. Thurman of St. Louis, thurmans system, powered by an internal combustion engine, traveled to the customers residence on a horse-drawn wagon as part of a door to door cleaning service. Corrine Dufour of Savannah, Georgia received two patents in 1899 and 1900 for another blown air system that seems to have featured the first use of an electric motor. In 1901 powered vacuum cleaners using suction were invented independently by British engineer Hubert Cecil Booth, Booth also may have coined the word vacuum cleaner. Kenneys was a stationary 4,000 lb. steam engine powered system with pipes and hoses reaching into all parts of the building. The first vacuum-cleaning device to be portable and marketed at the market was built in 1905 by Walter Griffiths. In 1906 James B. Kirby developed his first of many vacuums called the Domestic Cyclone It used water for dirt separation. In 1907 department store janitor James Murray Spangler of Canton, Ohio invented the first portable vacuum cleaner. Crucially, in addition to suction from a fan that blew the dirt and dust into a soap box and one of his wifes pillow cases. Their first vacuum was the 1908 Model O, which sold for $60, subsequent innovations included the beater bar in 1919, disposal filter bags in the 1920s, and an upright vacuum cleaner in 1926. In Continental Europe, the Fisker and Nielsen company in Denmark was the first to sell vacuum cleaners in 1910, the design weighed just 17.5 kg and could be operated by a single person. The Swedish company Electrolux launched the innovative Model V in 1921 that was designed to lie on the floor on two thin metal runners and this innovation, conceived by Electrolux founder Axel Wenner-Gren, became a standard feature on generations of future vacuum cleaners
11.
Limescale
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Limescale is the hard, off-white, chalky deposit found in kettles, hot-water boilers and the inside of inadequately maintained hot-water central heating systems. It is also found as a similar deposit on the inner surface of old pipe. In addition to being unsightly and hard to clean, limescale seriously impairs the operation or damages various components, the type found deposited on the heating elements of water heaters has a main component of calcium carbonate. Hard water contains calcium bicarbonate or similar ions, calcium salts, such as calcium bicarbonate and calcium carbonate are both more soluble in hot water than cold water. Thus, heating water does not cause calcium carbonate to precipitate per se, note that the CO2 is dissolved in the water. As the concentration of carbonate increases, calcium carbonate precipitates as the salt, as new cold water with dissolved calcium carbonate/bicarbonate is added and heated, CO2 gas is removed, carbonate concentration increases, and more calcium carbonate precipitates. Descaling agents are used to remove scale, prevention of scale build-up relies on the technologies of water softening. Calcium cations from hard water can combine with soap, which would dissolve in soft water. This combination often forms soap scum which precipitates out in a film on the interior surfaces of baths, sinks. Scale is often coloured because of the presence of iron-containing compounds, the three main iron compounds are wustite, hematite, and magnetite
12.
Tap (valve)
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A tap is a valve controlling the release of a liquid or gas. Tap is used in the British Isles and most of the Commonwealth for any type of valve, particularly the fittings that control water supply to bathtubs. Faucet is the most common term in the US, similar in use to tap in British English, spigot is used by professionals in the trade, and typically refers to an outdoor fixture. Silcock, same as spigot, referring to a cock that penetrates a foundation sill, wall hydrant, same as spigot Tap generally refers to a beer tap, though also appears as a descriptor in tap water. In kitchens and bathrooms, mixer taps are commonly used, in this case, hot and cold water from the two valves is mixed before reaching the outlet, allowing the water to emerge at any temperature between that of the hot and cold water supplies. Mixer taps were invented by Thomas Campbell of Saint John, New Brunswick and this helps avoid scalding or uncomfortable chilling as other water loads occur. Rather than two valves, mixer taps frequently use a single, more complex, valve controlled by a single handle. The handle moves up and down to control the amount of water flow, especially for baths and showers, the latest designs are thermostatic mixing valves that do this using a built-in thermostat, and can be mechanical or electronic. There are also faucets with color LEDs to show the temperature of the water, if separate taps are fitted, it may not be immediately clear which tap is hot and which is cold. The hot tap generally has a red indicator while the cold tap generally has a blue or green indicator, in the United States, the taps are frequently also labeled with an H or C. Note that in countries with Romance languages, the letters C for hot and this can create confusion when English speakers visit these countries or vice versa. Mixer taps may have a stripe or arrows indicating which side will give hot. In most countries, there is an arrangement of hot/cold taps. For example, in the United States and many other countries, many installations exist where this standard has been ignored. Mis-assembly of some single-valve mixer taps will exchange hot and cold if the fixture has been plumbed correctly. Most handles on homes are connected to the shaft and fastened down with a screw. This teeth and cog system is used on most modern faucets. Although most of the time a key is on industrial and commercial applications
13.
Mold
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A mold or mould is a fungus that grows in the form of multicellular filaments called hyphae. In contrast, fungi that can adopt a single-celled growth habit are called yeasts, molds are a large and taxonomically diverse number of fungal species in which the growth of hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a mycelium, is considered a single organism, the hyphae are generally transparent, so the mycelium appears like very fine, fluffy white threads over the surface. Cross-walls may delimit connected compartments along the hyphae, each containing one or multiple, the dusty texture of many molds is caused by profuse production of asexual spores formed by differentiation at the ends of hyphae. The mode of formation and shape of spores is traditionally used to classify molds. Many of these spores are colored, making the much more obvious to the human eye at this stage in its life-cycle. Molds are considered to be microbes and do not form a taxonomic or phylogenetic grouping. In the past, most molds were classified within the Deuteromycota, molds cause biodegradation of natural materials, which can be unwanted when it becomes food spoilage or damage to property. They also play important roles in biotechnology and food science in the production of foods, beverages, antibiotics, pharmaceuticals. There are thousands of species of molds, which have diverse life-styles including saprotrophs, mesophiles, psychrophiles and thermophiles. They all require moisture for growth and some live in aquatic environments, like all fungi, molds derive energy not through photosynthesis but from the organic matter on which they live, utilising heterotrophy. Typically, molds secrete hydrolytic enzymes, mainly from the hyphal tips and these enzymes degrade complex biopolymers such as starch, cellulose and lignin into simpler substances which can be absorbed by the hyphae. In this way molds play a role in causing decomposition of organic material. Many molds also synthesise mycotoxins and siderophores which, together with lytic enzymes, molds can also grow on stored food for animals and humans, making the food unpalatable or toxic and are thus a major source of food losses and illness. Many strategies for food preservation are to prevent or slow growth as well as growth of other microbes. Molds reproduce by producing large numbers of spores, which may contain a single nucleus or be multinucleate. Mold spores can be asexual or sexual, many species can produce both types, other mold spores have slimy sheaths and are more suited to water dispersal. Mold spores are spherical or ovoid single cells, but can be multicellular
14.
Bacteria
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Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods, Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology, There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants, Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of bodies and bacteria are responsible for the putrefaction stage in this process. In March 2013, data reported by researchers in October 2012, was published and it was suggested that bacteria thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, You can find microbes everywhere—theyre extremely adaptable to conditions, the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial particularly in the gut flora. However several species of bacteria are pathogenic and cause diseases, including cholera, syphilis, anthrax, leprosy. The most common fatal diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year. In developed countries, antibiotics are used to treat infections and are also used in farming, making antibiotic resistance a growing problem. Once regarded as constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and these evolutionary domains are called Bacteria and Archaea. The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, for about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota, however, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea, here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea
15.
Spider
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Spiders are air-breathing arthropods that have eight legs and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other orders of organisms, Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every habitat with the exceptions of air and sea colonization. As of November 2015, at least 45,700 spider species, anatomically, spiders differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax and abdomen, and joined by a small, cylindrical pedicel. Unlike insects, spiders do not have antennae, in all except the most primitive group, the Mesothelae, spiders have the most centralized nervous systems of all arthropods, as all their ganglia are fused into one mass in the cephalothorax. Unlike most arthropods, spiders have no extensor muscles in their limbs and their abdomens bear appendages that have been modified into spinnerets that extrude silk from up to six types of glands. Spider webs vary widely in size, shape and the amount of thread used. It now appears that the orb web may be one of the earliest forms. Spider-like arachnids with silk-producing spigots appeared in the Devonian period about 386 million years ago, true spiders have been found in Carboniferous rocks from 318 to 299 million years ago, and are very similar to the most primitive surviving suborder, the Mesothelae. The main groups of spiders, Mygalomorphae and Araneomorphae, first appeared in the Triassic period. It is estimated that 25 million tons of spiders kill 400–800 million tons of prey per year. Spiders use a range of strategies to capture prey, trapping it in sticky webs, lassoing it with sticky bolas, mimicking the prey to avoid detection. Spiders guts are too narrow to take solids, and they liquefy their food by flooding it with digestive enzymes and they also grind food with the bases of their pedipalps, as arachnids do not have the mandibles that crustaceans and insects have. Male spiders identify themselves by a variety of courtship rituals to avoid being eaten by the females. Males of most species survive a few matings, limited mainly by their life spans. Females weave silk egg-cases, each of which may contain hundreds of eggs, females of many species care for their young, for example by carrying them around or by sharing food with them. A minority of species are social, building communal webs that may house anywhere from a few to 50,000 individuals, social behavior ranges from precarious toleration, as in the widow spiders, to co-operative hunting and food-sharing. Although most spiders live for at most two years, tarantulas and other spiders can live up to 25 years in captivity. While the venom of a few species is dangerous to humans, scientists are now researching the use of venom in medicine
16.
Broom
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A broom is a cleaning tool consisting of usually stiff fibers attached to, and roughly parallel to, a cylindrical handle, the broomstick. It is thus a variety of brush with a long handle and it is commonly used in combination with a dustpan. A distinction is made between a hard broom and a soft broom, soft brooms are for sweeping walls of cobwebs and spiders. Hard brooms are for sweeping dirt off sidewalks, the word broom derives from the name of certain thorny shrubs used for sweeping. The name of the shrubs began to be used for the implement in Late Middle English. The song Buy Broom Buzzems still refers to the broom besom as one type of besom, flat brooms, made of broom corn, were invented by Shakers in the 19th century with the invention of the broom vice. A smaller whisk broom or brush is sometimes called a duster. In 1797, the quality of brooms changed when Levi Dickenson, a farmer in Hadley, Massachusetts, made a broom for his wife, using the tassels of sorghum and his wife spread good words around town, creating demand for Dickensons sorghum brooms. The sorghum brooms held up well, but ultimately, like all brooms, Dickenson subsequently invented a machine that would make better brooms, and faster than he could. In 1810, the foot treadle broom machine was invented and this machine played an integral part in the Industrial Revolution. In Swaziland, witches broomsticks are short bundles of tied together without a handle. One source mentions that the United States had 303 broom factories by 1839, most of these were in the Eastern United States, during the Great Depression in the 1930s, the number of factories declined to 320 in 1939. The state of Oklahoma became a center for broom production because broom corn grew especially well there. Faced with competition from imported brooms and synthetic bristles, most of the factories closed by the 1960s, in the context of witchcraft, broomstick is likely to refer to the broom as a whole, known as a besom. The first known reference to flying on broomsticks dates to 1453. The concept of an ointment used by witches appears at about the same time. In Metro-Goldwyn-Mayers 1939 film, The Wizard of Oz, the Wicked Witch of the West used a broomstick to fly over Oz and she also used it to skywrite Surrender Dorothy above the Emerald City. The Wizard commands Dorothy and her three traveling companions to bring the Wicked Witchs broomstick to him in order to grant their wishes, Dorothy carries it to the Wizard with the Scarecrow, Tin Man, and Lion after the Wicked Witchs death
17.
Mop
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A mop is a mass or bundle of coarse strings or yarn, etc. or a piece of cloth, sponge, or other absorbent material, attached to a pole or stick. It is used to soak up liquid, for cleaning floors and other surfaces, to mop up dust, the word is attested in English as early as 1496, but new refinements and variations of mop designs have been introduced, from time to time. For example, American inventor Jacob Howe received U. S. patent #241 for a mop holder in 1837, a dry mop or dust mop is designed to pick up dry, loose contamination such as dust, earth and sand from the surface of the floor. It consists of yarn and/or microfiber and is used as a first step in cleaning a floor, professional dry mops consist of a flat sheet of microfiber textile or sheets with a surface of looped yarn, usually about 15 cm wide, and comes in variable lengths. The dry mop can in many instances replace a broom and has the ability to hold an amount of dust or sand within itself. Oftentimes, the heads of dry mops are removable and can be washed and replaced when saturated with dust, another option is using a vacuum cleaner to suck surface dust away from the mop, however, this is much more limited in its effectiveness. Single-use dry mops are also available and widely sold, a wet mop or moist mop is, in professional cleaning, used as in the second step in the cleaning of a surface. The wet mop is swept over the surface to dissolve and absorb fat, mud, professional wet mops consist of a flat sheet of microfiber textile or a sheet with a surface of looped yarn, usually about 15 cm wide, and come in various lengths. Professional flat mops are made for pre-moisting, Mops are pre-impregnated with an ideal amount of water mixed with an appropriate amount of detergent. This means that the cleaner does not need to bring any additional water on the cleaning trolley and this ideal amount is often recommended by the manufacturer in terms of weight percent of water per weight of the dry mop, for example 175% water per weight of the dry mop. Mops for pre-moisting are flat sheets of textile, usually about 15 cm wide, Mops for pre-moisting are fastened on a handle with a flat pad mount with the aid of velcro or a pouch on the mop, in which the pad on the handle fits. Pre-moisting can be done with a washing machine or by hand by simply folding and packing the mops tight in a container. The mops will then need about 5–10 minutes for the liquid to distribute evenly in their tissue before use and this offers some advantages, The cleaner does not have to have a bucket of water with him/her when sweeping the floor, but simply carries an appropriate number of mops. This means the weight of the equipment can often be kept lower, the risk of over-wetting the floor and leave puddles is eliminated if the wetness is ideal. The hot mop follows a concept to a steam iron. After adding water, the water is heated to make it exude on top of a floor and these can work best on surfaces where a regular mop would also be used, such as bare floors, hearths, and laminate. A syntho-mop such as the Scooba is not considered a mop, because though it performs the same function as a traditional mop. Microfiber mops are constructed of a blend of polyester and polyamide fibers which are “split” and this blend consists of 70-90% polyester that serves as the scrubbing and cleaning fiber and 10–30% polyamide which performs as the holding and quick drying fiber
18.
Sponge (material)
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A sponge is a tool or cleaning aid consisting of soft, porous material. Usually used for cleaning surfaces, sponges are especially good at absorbing water. Sponges are commonly made from cellulose wood fibers or foamed plastic polymers, some natural sponges are still sold, with most now used either as body or facial sponges or as tools for sponge painting. Bath sponges help cleanse the skin by scraping away the dead skin, besides sponges formed from plastic polymers, the three other categories of widely available synthetic sponges are low-density polyether, PVA, and polyester. Polyester sponges can be subdivided into a variety of types, some of which are reticulated for ease of use, one type, double-blown polyester, has a high water-retention ability approaching or equaling that of PVA sponges, but with visible pores and more diverse uses. Because it is made of wood fiber, a cellulose sponge can be a medium for the growth of harmful bacteria or fungi. Several methods have used to clean sponges. Studies have investigated the use of the microwave to clean domestic sponges that have been thoroughly moistened. A2006 study found that microwaving wet sponges for two minutes killed 99% of coliforms, E. coli, and MS2 phages, but Bacillus cereus spores required four minutes. After some fires were caused by trying to replicate the results at home. A2009 study showed that the microwave and the dishwasher were both effective ways to clean domestic sponges, dishcloth Ethylene-vinyl acetate – material that craft foam is made from ethylene-vinyl and acetate Luffa aegyptiaca Polymer sponge – a medical innovation Scouring pad Sponge Sponge metal
19.
Detergent
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A detergent is a surfactant or a mixture of surfactants with cleaning properties in dilute solutions. In most household contexts, the term detergent by itself refers specifically to laundry detergent or dish detergent, detergents are commonly available as powders or concentrated solutions. Detergents, like soaps, work because they are amphiphilic, partly hydrophilic and their dual nature facilitates the mixture of hydrophobic compounds with water. Because air is not hydrophilic, detergents are also foaming agents to varying degrees, detergents are classified into three broad groupings, depending on the electrical charge of the surfactants. The alkylbenzene portion of these anions is lipophilic and the sulfonate is hydrophilic, two different varieties have been popularized, those with branched alkyl groups and those with linear alkyl groups. The former were phased out in economically advanced societies because they are poorly biodegradable. An estimated 6 billion kilograms of detergents are produced annually for domestic markets. Bile acids, such as acid, are anionic detergents produced by the liver to aid in digestion and absorption of fats. The ammonium center is positively charged, non-ionic detergents are characterized by their uncharged, hydrophilic headgroups. Typical non-ionic detergents are based on polyoxyethylene or a glycoside, common examples of the former include Tween, Triton, and the Brij series. These materials are known as ethoxylates or PEGlyates and their metabolites. Glycosides have a sugar as their uncharged hydrophilic headgroup, examples include octyl thioglucoside and maltosides. HEGA and MEGA series detergents are similar, possessing an alcohol as headgroup. Zwitterionic detergents possess a net zero charge arising from the presence of numbers of +1. In World War I, there was a shortage of oils, synthetic detergents were first made in Germany. One of the largest applications of detergents is for household cleaning including dish washing and washing laundry, the formulations are complex, reflecting the diverse demands of the application and the highly competitive consumer market. Both carburetors and fuel injector components of Otto engines benefit from detergents in the fuels to prevent fouling, typical detergents are long-chain amines and amides such as polyisobuteneamine and polyisobuteneamide/succinimide. Reagent grade detergents are employed for the isolation and purification of integral membrane proteins found in biological cells, solubilization of cell membrane bilayers requires a detergent that can enter the inner membrane monolayer
20.
Disinfectant
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Disinfectants are antimicrobial agents that are applied to the surface of non-living objects to destroy microorganisms that are living on the objects. Disinfectants are different from other agents such as antibiotics, which destroy microorganisms within the body, and antiseptics. Disinfectants are also different from biocides — the latter are intended to destroy all forms of life, Disinfectants work by destroying the cell wall of microbes or interfering with the metabolism. Sanitizer are substances that simultaneously clean and disinfect, Disinfectants are frequently used in hospitals, dental surgeries, kitchens, and bathrooms to kill infectious organisms. Bacterial endospores are most resistant to disinfectants, but some viruses, an alternative term used in the sanitation sector for disinfection of waste streams, sewage sludge or fecal sludge is sanitisation or sanitization. A perfect disinfectant would also complete and full microbiological sterilisation, without harming humans and useful form of life, be inexpensive. However, most disinfectants are also, by nature, potentially harmful to humans or animals, most modern household disinfectants contain Bitrex, an exceptionally bitter substance added to discourage ingestion, as a safety measure. Those that are used indoors should never be mixed with other cleaning products as chemical reactions can occur, the choice of disinfectant to be used depends on the particular situation. Some disinfectants have a spectrum, while others kill a smaller range of disease-causing organisms but are preferred for other properties. There are arguments for creating or maintaining conditions that are not conducive to survival and multiplication. Bacteria can increase in very quickly, which enables them to evolve rapidly. Should some bacteria survive an attack, they give rise to new generations composed completely of bacteria that have resistance to the particular chemical used. Under a sustained attack, the surviving bacteria in successive generations are increasingly resistant to the chemical used. For this reason, some question the wisdom of impregnating cloths, cutting boards, air disinfectants are typically chemical substances capable of disinfecting microorganisms suspended in the air. Disinfectants are generally assumed to be limited to use on surfaces, in 1928, a study found that airborne microorganisms could be killed using mists of dilute bleach. An air disinfectant must be dispersed either as an aerosol or vapour at a sufficient concentration in the air to cause the number of infectious microorganisms to be significantly reduced. In principle, these substances are ideal air disinfectants because they have both high lethality to microorganisms and low mammalian toxicity. The engineering challenge associated with creating a sufficient concentration of the glycol vapours in the air have not to date been sufficiently addressed, Alcohols are most effective when combined with distilled water to facilitate diffusion through the cell membrane, 100% alcohol typically denatures only external membrane proteins
21.
Recycling
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Recycling is the process of converting waste materials into new materials and objects. It is an alternative to conventional waste disposal that can save material, Recycling can prevent the waste of potentially useful materials and reduce the consumption of fresh raw materials, thereby reducing, energy usage, air pollution, and water pollution. Recycling is a key component of waste reduction and is the third component of the Reduce, Reuse. There are some ISO standards related to recycling such as ISO15270,2008 for plastics waste, recyclable materials include many kinds of glass, paper, and cardboard, metal, plastic, tires, textiles, and electronics. The composting or other reuse of biodegradable waste—such as food or garden waste—is also considered recycling, materials to be recycled are either brought to a collection centre or picked up from the curbside, then sorted, cleaned, and reprocessed into new materials destined for manufacturing. However, this is difficult or too expensive, so recycling of many products or materials involves their reuse in producing different materials instead. Another form of recycling is the salvage of materials from complex products, either due to their intrinsic value. Recycling has been a practice for most of human history. In pre-industrial times, there is evidence of bronze and other metals being collected in Europe. Paper recycling was first recorded in 1031 when Japanese shops sold repulped paper, in Britain dust and ash from wood and coal fires was collected by dustmen and downcycled as a base material used in brick making. In 1813, Benjamin Law developed the process of turning rags into shoddy and mungo wool in Batley and this material combined recycled fibers with virgin wool. The West Yorkshire shoddy industry in such as Batley and Dewsbury lasted from the early 19th century to at least 1914. Industrialization spurred demand for materials, aside from rags, ferrous scrap metals were coveted as they were cheaper to acquire than virgin ore. Railroads both purchased and sold scrap metal in the 19th century, and the steel and automobile industries purchased scrap in the early 20th century. Many secondary goods were collected, processed and sold by peddlers who scoured dumps and city streets for discarded machinery, pots, pans, and other sources of metal. By World War I, thousands of such peddlers roamed the streets of American cities, beverage bottles were recycled with a refundable deposit at some drink manufacturers in Great Britain and Ireland around 1800, notably Schweppes. New chemical industries created in the late 19th century both invented new materials (e. g. Bakelite and promised to transform valueless into valuable materials, new and better paths are opened to reach the goals desired. Recycling was a highlight throughout World War II, during the war, financial constraints and significant material shortages due to war efforts made it necessary for countries to reuse goods and recycle materials
22.
Dust
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Dust is fine particles of matter. It generally consists of particles in the atmosphere that come from sources such as soil, dust lifted by weather, volcanic eruptions. House dust mites are present indoors wherever humans live, positive tests for dust mite allergies are extremely common among people with asthma. Dust mites are microscopic arachnids whose primary food is dead skin cells. They and their feces and other allergens they produce are major constituents of house dust and they are generally found on the floor and other surfaces until disturbed. It could take somewhere between twenty minutes and two hours for dust mites to settle back down out of the air, Dust mites are a nesting species that prefers a dark, warm, and humid climate. They flourish in mattresses, bedding, upholstered furniture, and carpets and their feces include enzymes that are released upon contact with a moist surface, which can happen when a person inhales, and these enzymes can kill cells within the human body. House dust mites did not become a problem until humans began to use textiles, such as western style blankets and clothing. Atmospheric or wind-borne dust, also known as aeolian dust, comes from arid and dry regions where high velocity winds are able to remove mostly silt-sized material, Dust in the atmosphere is produced by saltation and sandblasting of sand-sized grains, and it is transported through the troposphere. This airborne dust is considered an aerosol and once in the atmosphere, saharan dust in particular can be transported and deposited as far as the Caribbean and the Amazon basin, and may affect air temperatures, cause ocean cooling, and alter rainfall amounts. Dust in the Middle East has been a historic phenomenon, recently, because of climate change and the escalating process of desertification, the problem has worsened dramatically. As a multi-factor phenomenon, there is not yet a consensus on the sources or potential solutions to the problem. In Iran, the dust is already affecting more than 5 million people directly, in the province of Khuzestan it has led to the severe reduction of air quality. The amount of pollutants in the air has surpassed more than 50 times the normal level several times in a year, recently, initiatives such as Project-Dust have been established to directly study the Middle Eastern dust. Dust kicked up by vehicles traveling on roads may make up 33% of air pollution, road dust consists of deposits of vehicle exhausts and industrial exhausts, particles from tire and brake wear, dust from paved roads or potholes, and dust from construction sites. Road dust is a significant source contributing to the generation and release of particulate matter into the atmosphere. Control of road dust is a significant challenge in urban areas, road dust may be suppressed by mechanical methods like street sweeper vehicles equipped with vacuum cleaners, vegetable oil sprays, or with water sprayers. Improvements in automotive engineering have reduced the amount of PM10s produced by road traffic, coal dust is responsible for the lung disease known as pneumoconiosis, including black lung disease that occurs among coal miners
23.
Feather duster
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A feather duster is an implement used for cleaning. It consists typically of a handle and feathers from either the male or female ostrich bird that are wound onto the handle by a wrapped wire. Dusters vary in size but are most often between 14 to 32 inches in total length, some dusters have a retractable casing instead of a dowel handle. These dusters are used by rack-jobbers and truck drivers who need to dust store shelves. Feather dusters are effective in dusting tight areas, or areas where there are a lot of odds and ends to dust around, the individual feathers are able to penetrate through the knick-knacks and pull the dust out of the area without disturbing items. On large open surfaces or walls, or in trying to get spider webs in the ceiling, in 1870, the original idea for the feather duster was conceived in a broom factory in Jones County, Iowa, U. S. A farmer brought a bundle of feathers into the factory asking if they could be used to assemble a brush. Hoag used these feathers to invent the first feather duster, using a short broom stick and splitting the feathers with a pocket knife, the duster was found to be too stiff for use. In 1874, the Hoag Duster Company was founded, which became a pioneer of feather dusters in the U. S. state of Iowa, in 1874, Susan Hibbard of Geneva Lake, Wisconsin, U. S. used discarded turkey feathers to invent a feather duster. Hibbard filed a patent on November 13,1874 which was issued on May 30,1876, South African ostrich feather dusters were developed in Johannesburg, South Africa by missionary, broom factory manager, Harry S. Beckner in 1903. He felt that the Ostrich feathers made a convenient tool for cleaning up the machines at the broom factory and his first ostrich feather dusters were wound on broom handles using the foot powered kick winders and the same wire used to attach broom straw. The Chicago Feather Duster Company was established in 1875 and they received a patent for the head of the duster on September 17,1907 along with a patent for the cuff on December 22,1906. The first ostrich feather duster company in the United States was formed in 1913 by Harry S, today the largest manufacturer of Ostrich Feather Dusters is Klein Karoo International which is located in Oudtshoorn, South Africa. The feather duster was considered a symbol in the late 19th. There are several types of feathers used in feather dusters, feathers for dusters are the ostrich families most valuable industrial commodity. Black ostrich feathers come from the ostrich and are very soft with feathers that are more stringy in nature. Gray ostrich feathers are more stark than the black feathers and are sold at grocery stores. Floss ostrich feathers are the most soft and delicate feathers and come from underneath the birds wings, floss ostrich feathers are more expensive
24.
Detritus
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In biology, detritus is dead particulate organic material. It typically includes the bodies or fragments of organisms as well as fecal material. Detritus is typically colonized by communities of microorganisms which act to decompose the material, in terrestrial ecosystems, it is encountered as leaf litter and other organic matter intermixed with soil, which is referred to as humus. Detritus of aquatic ecosystems is organic material suspended in water and piles up on seabed floors which is referred to as marine snow. Dead plants or animals, material derived from animal tissues gradually lose their form, decomposition, the process through which organic matter is decomposed, takes place in many stages. Materials like proteins, lipids and sugars with low weight are rapidly consumed and absorbed by micro-organisms and organisms that feed on dead matter. Other compounds, such as complex carbohydrates are broken down more slowly, the various micro-organisms involved in the decomposition break down the organic materials in order to gain the resources they require for their own survival and proliferation. Accordingly, at the time that the materials of plants and animals are being broken down. In ecosystems on land, detritus is deposited on the surface of the ground, in aquatic ecosystems, most detritus is suspended in water, and gradually settles. In particular, many different types of material are collected together by currents, much detritus is used as a source of nutrition for animals. In particular, many bottom feeding animals living in mud flats feed in this way, however, there are many micro-organisms which multiply in natural environments. A characteristic type of food chain called the cycle takes place involving detritus feeders, detritus. For example, mud flats are inhabited by many univalves which are detritus feeders, what is left behind by the detritivores is then further broken down and recycled by decomposers, such as bacteria and fungi. In ecosystems on land, far more material is broken down as dead material passing through the detritus chain than is broken down by being eaten by animals in a living state. In both land and aquatic ecosystems, the role played by detritus is too large to ignore, in contrast to land ecosystems, dead materials and excreta in aquatic ecosystems do not settle immediately, and the finer the particles involved are, the longer they tend to take. Detritus occurs in a variety of habitats including forest, chaparral. In forests the detritus is typically dominated by leaf, twig and this plant litter provides important cover for seedling protection as well as cover for a variety of arthropods, reptiles and amphibians. Some insect larvae feed on the detritus, there is an extremely large number of detritus feeders in water
25.
Safety data sheet
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A safety data sheet, material safety data sheet, or product safety data sheet is an important component of product stewardship, occupational safety and health, and spill-handling procedures. SDS formats can vary from source to source within a country depending on national requirements, SDSs are a widely used system for cataloging information on chemicals, chemical compounds, and chemical mixtures. SDS information may include instructions for the use and potential hazards associated with a particular material or product. The SDS should be available for reference in the area where the chemicals are being stored or in use, there is also a duty to properly label substances on the basis of physico-chemical, health and/or environmental risk. Labels can include hazard symbols such as the European Union standard symbols, a SDS for a substance is not primarily intended for use by the general consumer, focusing instead on the hazards of working with the material in an occupational setting. It is important to use an SDS specific to country and supplier, as the same product can have different formulations in different countries. The formulation and hazard of a product using a name may vary between manufacturers in the same country. Safety data sheets have made an integral part of the system of Regulation No 1907/2006. The SDS must be supplied in a language of the Member State where the substance or mixture is placed on the market. The 16 sections are, SECTION1, Identification of the substance/mixture, relevant identified uses of the substance or mixture and uses advised against 1.3. Details of the supplier of the safety data sheet 1.4, Emergency telephone number SECTION2, Hazards identification 2.1. Classification of the substance or mixture 2.2, Other hazards SECTION3, Composition/information on ingredients 3.1. Mixtures SECTION4, First aid measures 4.1, Description of first aid measures 4.2. Most important symptoms and effects, both acute and delayed 4.3, indication of any immediate medical attention and special treatment needed SECTION5, Firefighting measures 5.1. Special hazards arising from the substance or mixture 5.3, advice for firefighters SECTION6, Accidental release measure 6.1. Personal precautions, protective equipment and emergency procedures 6.2, methods and material for containment and cleaning up 6.4. Reference to other sections SECTION7, Handling and storage 7.1, conditions for safe storage, including any incompatibilities 7.3. Specific end use SECTION8, Exposure controls/personal protection 8.1, Exposure controls SECTION9, Physical and chemical properties 9.1
26.
Surfactant
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Surfactants are compounds that lower the surface tension between two liquids or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, the term surfactant is a blend of surface active agent. In the United States National Library of Medicines Medical Subject Headings vocabulary, for the more general meaning, surface active agent/s is the heading. Surfactants are usually organic compounds that are amphiphilic, meaning they contain both hydrophobic groups and hydrophilic groups, therefore, a surfactant contains both a water-insoluble component and a water-soluble component. Surfactants will diffuse in water and adsorb at interfaces between air and water or at the interface between oil and water, in the case where water is mixed with oil. The water-insoluble hydrophobic group may extend out of the water phase, into the air or into the oil phase. World production of surfactants is estimated at 15 Mton/y, of which half are soaps. Other surfactants produced on a large scale are linear alkylbenzenesulfonates, lignin sulfonates, fatty alcohol ethoxylates. Other types of aggregates can also be formed, such as spherical or cylindrical micelles or lipid bilayers, the shape of the aggregates depends on the chemical structure of the surfactants, namely the balance in size between hydrophilic head and hydrophobic tail. A measure of this is the HLB, Hydrophilic-lipophilic balance, Surfactants reduce the surface tension of water by adsorbing at the liquid-air interface. The relation that links the surface tension and the excess is known as the Gibbs isotherm. The dynamics of adsorption depend on the coefficient of the surfactant. As the interface is created, the adsorption is limited by the diffusion of the surfactant to the interface, in some cases, there can exist an energetic barrier to adsorption or desorption of the surfactant. If such a barrier limits the rate, the dynamics are said to be ‘kinetically limited. Such energy barriers can be due to steric or electrostatic repulsions, the surface rheology of surfactant layers, including the elasticity and viscosity of the layer, play an important role in the stability of foams and emulsions. Interfacial and surface tension can be characterized by classical methods such as the -pendant or spinning drop method, surface rheology can be characterized by the oscillating drop method or shear surface rheometers such as double-cone, double-ring or magnetic rod shear surface rheometer. In solution, detergents help solubilize a variety of species by dissociating aggregates. Popular surfactants in the laboratory are SDS and CTAB
27.
Alkaline
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Alkalinity is the name given to the quantitative capacity of an aqueous solution to neutralize an acid. Measuring alkalinity is important in determining a streams ability to neutralize acidic pollution from rainfall or wastewater and it is one of the best measures of the sensitivity of the stream to acid inputs. There can be changes in the alkalinity of streams and rivers in response to human disturbances. Alkalinity is related to the pH of a solution, but measures a different property, roughly, the alkalinity of a solution is a measure of how strong the bases are in a solution, whereas the pH measures the amount of chemical bases. A good example is a solution, which can have many available bases despite having only a moderate pH level. Alkalinity roughly refers to the amount of bases in a solution that can be converted to uncharged species by a strong acid. The cited author, James Drever, provides an equation expressed in terms of molar equivalents, which means the number of moles of each ion type multiplied by the charge of the ion. For example,1 mole of HCO31− in solution represents 1 molar equivalent, the total charge of a solution always equals zero. On the left-hand side of the equation is the sum of conservative cations minus the sum of conservative anions, balancing this on the right side is the sum of the anions that could be neutralized by added H+ ions minus H+ ions already present, as indicated by the pH. This right side term is called total alkalinity and it is, quoting Drever, formally defined as the equivalent sum of the bases that are titratable with strong acid. The listing of ions shown on the right in Drever was mHCO3− + 2mCO32− + mB4− + mH34− + mHS− + morganic anions + mOH− - mH+, total alkalinity is measured by adding a strong acid until all the anions listed above are converted to uncharged species. The total alkalinity is not affected by temperature, pressure, or pH, though the values of individual constituents are, Drever further notes that in most natural waters, all ions except HCO3− and CO3−2 have low concentrations. Thus carbonate alkalinity, which is equal to mHCO3− + 2mCO3−2 is also equal to the total alkalinity. Alkalinity or AT measures the ability of a solution to neutralize acids to the point of carbonate or bicarbonate. The alkalinity is equal to the sum of the bases in solution. Other common natural components that can contribute to alkalinity include borate, hydroxide, phosphate, silicate, dissolved ammonia, the bases of some organic acids. Solutions produced in a laboratory may contain a virtually limitless number of bases that contribute to alkalinity, Alkalinity is usually given in the unit mEq/L. Commercially, as in the pool industry, alkalinity might also be given in parts per million of equivalent calcium carbonate
28.
Acid
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An acid is a molecule or ion capable of donating a hydron, or, alternatively, capable of forming a covalent bond with an electron pair. The first category of acids is the donors or Brønsted acids. In the special case of solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents, acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals to form salts. The word acid is derived from the Latin acidus/acēre meaning sour, an aqueous solution of an acid has a pH less than 7 and is colloquially also referred to as acid, while the strict definition refers only to the solute. A lower pH means a higher acidity, and thus a higher concentration of hydrogen ions in the solution. Chemicals or substances having the property of an acid are said to be acidic, common aqueous acids include hydrochloric acid, acetic acid, sulfuric acid, and citric acid. As these examples show, acids can be solutions or pure substances, strong acids and some concentrated weak acids are corrosive, but there are exceptions such as carboranes and boric acid. The second category of acids are Lewis acids, which form a covalent bond with an electron pair, however, hydrogen chloride, acetic acid, and most other Brønsted-Lowry acids cannot form a covalent bond with an electron pair and are therefore not Lewis acids. Conversely, many Lewis acids are not Arrhenius or Brønsted-Lowry acids, in modern terminology, an acid is implicitly a Brønsted acid and not a Lewis acid, since chemists almost always refer to a Lewis acid explicitly as a Lewis acid. Modern definitions are concerned with the chemical reactions common to all acids. Most acids encountered in life are aqueous solutions, or can be dissolved in water, so the Arrhenius. The Brønsted-Lowry definition is the most widely used definition, unless otherwise specified, hydronium ions are acids according to all three definitions. Interestingly, although alcohols and amines can be Brønsted-Lowry acids, they can function as Lewis bases due to the lone pairs of electrons on their oxygen and nitrogen atoms. The Swedish chemist Svante Arrhenius attributed the properties of acidity to hydrogen ions or protons in 1884, an Arrhenius acid is a substance that, when added to water, increases the concentration of H+ ions in the water. Thus, an Arrhenius acid can also be described as a substance that increases the concentration of ions when added to water. Examples include molecular substances such as HCl and acetic acid, an Arrhenius base, on the other hand, is a substance which increases the concentration of hydroxide ions when dissolved in water. Thus, an Arrhenius acid could also be said to be one that decreases hydroxide concentration, in an acidic solution, the concentration of hydronium ions is greater than 10−7 moles per liter
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PH
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In chemistry, pH is a numeric scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the concentration, measured in units of moles per liter. More precisely it is the negative of the logarithm to base 10 of the activity of the hydrogen ion, solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic. Pure water is neutral, at pH7, being neither an acid nor a base, contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively. The pH scale is traceable to a set of standard solutions whose pH is established by international agreement, the pH of aqueous solutions can be measured with a glass electrode and a pH meter, or an indicator. In the first papers, the notation had the H as a subscript to the p, as so. The exact meaning of the p in pH is disputed, but according to the Carlsberg Foundation and it has also been suggested that the p stands for the German Potenz, others refer to French puissance. Another suggestion is that the p stands for the Latin terms pondus hydrogenii, potentia hydrogenii and it is also suggested that Sørensen used the letters p and q simply to label the test solution and the reference solution. Currently in chemistry, the p stands for decimal cologarithm of, PH is defined as the decimal logarithm of the reciprocal of the hydrogen ion activity, aH+, in a solution. P H = − log 10 = log 10 For example and this definition was adopted because ion-selective electrodes, which are used to measure pH, respond to activity. For H+ number of electrons transferred is one and it follows that electrode potential is proportional to pH when pH is defined in terms of activity. The reference electrode may be a silver chloride electrode or a calomel electrode, the hydrogen-ion selective electrode is a standard hydrogen electrode. Reference electrode | concentrated solution of KCl || test solution | H2 | Pt Firstly, the cell is filled with a solution of hydrogen ion activity. Then the emf, EX, of the cell containing the solution of unknown pH is measured. PH = pH + E S − E X z The difference between the two measured emf values is proportional to pH and this method of calibration avoids the need to know the standard electrode potential. The proportionality constant, 1/z is ideally equal to 12.303 R T / F the Nernstian slope, to apply this process in practice, a glass electrode is used rather than the cumbersome hydrogen electrode. A combined glass electrode has a reference electrode. It is calibrated against buffer solutions of hydrogen ion activity
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Chloramine
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Chloramines are derivatives of ammonia by substitution of one, two or three hydrogen atoms with chlorine atoms, monochloramine, dichloramine, and nitrogen trichloride. The term chloramine also refers to a family of compounds with the formulas R2NCl. Monochloramine is a compound with the formula NH2Cl. It is a colorless liquid at its melting point of −66 °C. The wholesale cost in the world is about 13.80 to 18.41 USD per 500 gms. Chloramine is used as a disinfectant for water because it is less aggressive than chlorine, NH2Cl is commonly used in low concentrations as a secondary disinfectant in municipal water distribution systems as an alternative to chlorination. Chlorine is being displaced by chloramine—to be specific monochloramine—which is much more stable, NH2Cl also has a very much lower, however still present, tendency than free chlorine to convert organic materials into chlorocarbons such as chloroform and carbon tetrachloride. Such compounds have been identified as carcinogens and in 1979 the United States Environmental Protection Agency began regulating their levels in U. S. drinking water, some of the unregulated byproducts may possibly pose greater health risks than the regulated chemicals. In swimming pools, chloramines are formed by the reaction of chlorine with organic substances, such as urine. Chloramines, compared to free chlorine, are less effective as a sanitizer and, if not managed correctly, more irritating to the eyes of swimmers. Chloramines are also responsible for the chlorine smell of swimming pools. Some pool test kits designed for use by homeowners are not able to free chlorine and chloramines. There is also evidence that exposure to chloramine can contribute to problems, including asthma. Respiratory problems related to chloramine exposure are common and prevalent among competitive swimmers, US EPA drinking water quality standards limit chloramine concentration for public water systems to 4 parts per million based on a running annual average of all samples in the distribution system. In order to meet EPA-regulated limits on halogenated disinfection by-products, many utilities are switching from chlorination to chloramination, both iodinated disinfection by-products and N-nitrosodimethylamine have been shown to be genotoxic. NH2Cl is an unstable compound in concentrated form. Pure NH2Cl decomposes violently above −40 °C, gaseous chloroamine at low pressures and low concentrations of chloroamine in aqueous solution are thermally slightly more stable. Chloroamine is readily soluble in water and ether, but less soluble in chloroform, in dilute aqueous solution, chloroamine is prepared by the reaction of ammonia with sodium hypochlorite, NH3 + OCl− ⟶ NH2Cl + HO− This is also the first step of the Raschig hydrazine synthesis
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Inflammation
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The classical signs of inflammation are heat, pain, redness, swelling, and loss of function. Inflammation is a response, and therefore it is considered as a mechanism of innate immunity, as compared to adaptive immunity. Too little inflammation could lead to tissue destruction by the harmful stimulus. In contrast, chronic inflammation may lead to a host of diseases, such as hay fever, periodontitis, atherosclerosis, rheumatoid arthritis, Inflammation is therefore normally closely regulated by the body. Inflammation can be classified as acute or chronic. Acute inflammation is the response of the body to harmful stimuli and is achieved by the increased movement of plasma. A series of biochemical events propagates and matures the inflammatory response, involving the vascular system, the immune system. Inflammation is not a synonym for infection, Inflammation on the other hand describes purely the bodys immunovascular response, whatever the cause may be. But because of how often the two are correlated, words ending in the suffix -itis are sometimes described as referring to infection. There are also situations where microbial invasion does not result in classic inflammatory response—for example, parasitosis. Acute inflammation is a process, usually appearing within a few minutes or hours. It involves a coordinated and systemic mobilisation response locally of various immune, endocrine, in a normal healthy response, it becomes activated, clears the pathogen and begins a repair process and then ceases. It is characterized by five signs, An acronym that may be used to remember the key symptoms is PRISH, for pain, redness, immobility, swelling. Loss of function has multiple causes, Acute inflammation of the lung does not cause pain unless the inflammation involves the parietal pleura, which does have pain-sensitive nerve endings. PAMPs are compounds that are associated with pathogens, but which are distinguishable from host molecules. DAMPs are compounds that are associated with host-related injury and cell damage, at the onset of an infection, burn, or other injuries, these cells undergo activation and release inflammatory mediators responsible for the clinical signs of inflammation. Vasodilation and its resulting increased blood flow causes the redness and increased heat, increased permeability of the blood vessels results in an exudation of plasma proteins and fluid into the tissue, which manifests itself as swelling. Some of the released mediators such as increase the sensitivity to pain
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Indoor air quality
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Indoor air quality is a term which refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. IAQ can be affected by gases, particulates, microbial contaminants, source control, filtration and the use of ventilation to dilute contaminants are the primary methods for improving indoor air quality in most buildings. Residential units can further improve air quality by routine cleaning of carpets. Determination of IAQ involves the collection of air samples, monitoring human exposure to pollutants, collection of samples on building surfaces, IAQ is part of indoor environmental quality, which includes IAQ as well as other physical and psychological aspects of life indoors. Indoor air pollution in developing nations is a health hazard. A major source of air pollution in developing countries is the burning of biomass for heating and cooking. The resulting exposure to high levels of particulate matter resulted in between 1.5 million and 2 million deaths in 2000, second-hand smoke is tobacco smoke which affects other people other than the active smoker. The only certain method to improve air quality as regards second-hand smoke is the implementation of comprehensive smoke-free laws. Radon is an invisible, radioactive gas that results from the radioactive decay of radium. Radon is probably the most pervasive serious hazard for air in the United States and Europe. There are relatively simple test kits for do-it-yourself radon gas testing, radon gas enters buildings as a soil gas and is a heavy gas and thus will tend to accumulate at the lowest level. Radon may also be introduced into a building through drinking water particularly from bathroom showers, the half life for radon is 3.8 days, indicating that once the source is removed, the hazard will be greatly reduced within a few weeks. Radon mitigation methods include sealing concrete slab floors, basement foundations, water drainage systems and they are usually cost effective and can greatly reduce or even eliminate the contamination and the associated health risks. Mold is always associated with moisture, and its growth can be inhibited by keeping humidity levels below 50%, in areas where cellulosic materials become moist and fail to dry within 48 hours, mold mildew can propagate and release allergenic spores into the air. In many cases, if materials have failed to dry out several days after the suspected water event, through a mold investigation, which may include destructive inspection, one should be able to determine the presence or absence of mold. In a situation there is visible mold and the indoor air quality may have been compromised. There are some varieties of mold that contain toxic compounds, however, exposure to hazardous levels of mycotoxin via inhalation is not possible in most cases, as toxins are produced by the fungal body and are not at significant levels in the released spores. The primary hazard of mold growth, as it relates to air quality
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Particulates
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Atmospheric particulate matter – also known as particulate matter or particulates – are microscopic solid or liquid matter suspended in the Earths atmosphere. The term aerosol commonly refers to the mixture, as opposed to the particulate matter alone. Sources of particulate matter can be man-made or natural and they have impacts on climate and precipitation that adversely affect human health. The smaller PM2.5 were particularly deadly, with a 36% increase in lung cancer per 10 μg/m3 as it can penetrate deeper into the lungs, some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes, coal combustion in developing countries is the primary method for heating homes and supplying energy. The composition of aerosols and particles depends on their source, wind-blown mineral dust tends to be made of mineral oxides and other material blown from the Earths crust, this particulate is light-absorbing. In addition, sea spray aerosols may contain organic compounds, which influence their chemistry, Secondary particles derive from the oxidation of primary gases such as sulfur and nitrogen oxides into sulfuric acid and nitric acid. The gases from which they originate—may have an origin and a natural biogenic origin. In the presence of ammonia, secondary aerosols often take the form of ammonium salts and this is mainly because the presence of sulfate and nitrate causes the aerosols to increase to a size that scatters light effectively. Organic matter can be primary or secondary, the latter part deriving from the oxidation of VOCs. Organic matter influences the atmospheric radiation field by both scattering and absorption, another important aerosol type is elemental carbon, this aerosol type includes strongly light-absorbing material and is thought to yield large positive radiative forcing. Organic matter and elemental carbon together constitute the carbonaceous fraction of aerosols, Secondary organic aerosols, tiny tar balls resulting from combustion products of internal combustion engines, have been identified as a danger to health. The chemical composition of the aerosol directly affects how it interacts with solar radiation, the chemical constituents within the aerosol change the overall refractive index. The refractive index will determine how light is scattered and absorbed. The particles are hygroscopic due to the presence of sulfur, and SO2 is converted to sulfate when high humidity and this causes the reduced visibility and yellow color. Aerosol particles of natural origin tend to have a larger radius than human-produced aerosols such as particle pollution, the false-color maps in the third image on this page show where there are natural aerosols, human pollution, or a mixture of both, monthly. Most of the Southern Hemisphere is covered by ocean, where the largest source of aerosols is natural sea salt from dried sea spray. Because land is concentrated in the Northern Hemisphere, the amount of small aerosols from fires, over land, patches of large-radius aerosols appear over deserts and arid regions, most prominently, the Sahara Desert in north Africa and the Arabian Peninsula, where dust storms are common
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Combustion
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Combustion in a fire produces a flame, and the heat produced can make combustion self-sustaining. Combustion is often a sequence of elementary radical reactions. Solid fuels, such as wood, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the required to produce more of them. Combustion is often hot enough that light in the form of either glowing or a flame is produced, a simple example can be seen in the combustion of hydrogen and oxygen into water vapor, a reaction commonly used to fuel rocket engines. The bond energies in the play only a minor role, since they are similar to those in the combustion products. The heat of combustion is approximately -418 kJ per mole of O2 used up in the combustion reaction, uncatalyzed combustion in air requires fairly high temperatures. Complete combustion is stoichiometric with respect to the fuel, where there is no remaining fuel, thermodynamically, the chemical equilibrium of combustion in air is overwhelmingly on the side of the products. Thus, the smoke is usually toxic and contains unburned or partially oxidized products. Since combustion is rarely clean, flue gas cleaning or catalytic converters may be required by law, fires occur naturally, ignited by lightning strikes or by volcanic products. Combustion was the first controlled chemical reaction discovered by humans, in the form of campfires and bonfires, usually, the fuel is carbon, hydrocarbons or more complicated mixtures such as wood that contains partially oxidized hydrocarbons. Combustion is also currently the only used to power rockets. Combustion is also used to destroy waste, both nonhazardous and hazardous, oxidants for combustion have high oxidation potential and include atmospheric or pure oxygen, chlorine, fluorine, chlorine trifluoride, nitrous oxide and nitric acid. For instance, hydrogen burns in chlorine to form hydrogen chloride with the liberation of heat, although usually not catalyzed, combustion can be catalyzed by platinum or vanadium, as in the contact process. In complete combustion, the reactant burns in oxygen, producing a number of products. When a hydrocarbon burns in oxygen, the reaction will yield carbon dioxide. When elements are burned, the products are primarily the most common oxides, carbon will yield carbon dioxide, sulfur will yield sulfur dioxide, and iron will yield iron oxide. Nitrogen is not considered to be a combustible substance when oxygen is the oxidant, Combustion is not necessarily favorable to the maximum degree of oxidation, and it can be temperature-dependent. For example, sulfur trioxide is not produced quantitatively by the combustion of sulfur, NOx species appear in significant amounts above about 2,800 °F, and more is produced at higher temperatures
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Pollen
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Pollen is a fine to coarse powdery substance comprising pollen grains which are male microgametophytes of seed plants, which produce male gametes. If pollen lands on a compatible pistil or female cone, it germinates, individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is useful in paleoecology, paleontology, archaeology. Pollen in plants is used for transferring haploid male genetic material from the anther of a flower to the stigma of another in cross-pollination. In a case of self-pollination, this takes place from the anther of a flower to the stigma of the same flower. Pollen itself is not the male gamete, each pollen grain contains vegetative cells and a generative cell. In flowering plants the vegetative tube cell produces the pollen tube, pollen is produced in the microsporangia in the male cone of a conifer or other gymnosperm or in the anthers of an angiosperm flower. Pollen grains come in a variety of shapes, sizes. Pollen grains of pines, firs, and spruces are winged, the smallest pollen grain, that of the forget-me-not, is around 6 µm in diameter. Wind-borne pollen grains can be as large as about 90–100 µm, in angiosperms, during flower development the anther is composed of a mass of cells that appear undifferentiated, except for a partially differentiated dermis. As the flower develops, four groups of cells form within the anther. The fertile sporogenous cells are surrounded by layers of cells that grow into the wall of the pollen sac. Some of the cells grow into nutritive cells that supply nutrition for the microspores that form by meiotic division from the sporogenous cells, in a process called microsporogenesis, four haploid microspores are produced from each diploid sporogenous cell, after meiotic division. After the formation of the four microspores, which are contained by callose walls, the exine is what is preserved in the fossil record. Two basic types of microsporogenesis are recognised, simultaneous and successive, in simultaneous microsporogenesis meiotic steps I and II are completed prior to cytokinesis, whereas in successive microsporogenesis cytokinesis follows. While there may be a continuum with intermediate forms, the type of microsporogenesis has systematic significance, the predominant form amongst the monocots is successive, but there are important exceptions. During microgametogenesis, the unicellular microspores undergo mitosis and develop into mature microgametophytes containing the gametes, in some flowering plants, germination of the pollen grain may begin even before it leaves the microsporangium, with the generative cell forming the two sperm cells. Except in the case of submerged aquatic plants, the mature pollen grain has a double wall
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Polycyclic aromatic hydrocarbon
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Polycyclic aromatic hydrocarbons are hydrocarbons—organic compounds containing only carbon and hydrogen—that are composed of multiple aromatic rings. Formally, the class is defined as lacking further branching substituents on these ring structures. Polynuclear aromatic hydrocarbons are a subset of PAHs that have fused aromatic rings, the simplest such chemicals are naphthalene, having two aromatic rings, and the three-ring compounds anthracene and phenanthrene. PAHs are neutral, nonpolar molecules found in coal and in tar deposits and they are produced as well by incomplete combustion of organic matter. The tricyclic species phenanthrene and anthracene represent the members of the PAHs. Smaller molecules, such as benzene, are not PAHs, PAHs with five or six-membered rings are most common. Those composed only of six-membered rings are called alternant PAHs, which include benzenoid PAHs, the following are examples of PAHs that vary in the number and arrangement of their rings, Examples of PAH compounds PAHs are nonpolar and lipophilic. Larger PAHs are generally insoluble in water, while some PAHs are soluble, the larger members are also poorly soluble in organic solvents as well as lipids. Although PAHs clearly are aromatic compounds, the degree of aromaticity can be different for each ring segment, according to Clars rule for PAHs the resonance structure with the largest number of disjoint aromatic п-sextets—i. e. Benzene-like moieties—is the most important for the characterization of the properties, in contrast, in anthracene the resonance structures have one sextet, which can be at any of the three rings, and the aromaticity spreads out more evenly across the whole molecule. Three Clar structures with two each are present in chrysene. Superposition of these reveals that the aromaticity in the outer rings is greater compared to the inner rings. Polycyclic aromatic hydrocarbons are found in natural sources such as creosote. They can result from the combustion of organic matter. PAHs can also be produced geologically when organic sediments are transformed into fossil fuels such as oil. Wild fires are another notable source, substantially higher outdoor air, soil, and water concentrations of PAHs have been measured in Asia, Africa, and Latin America than in Europe, Australia, and the U. S. /Canada. PAHs are typically found as complex mixtures, most PAHs are insoluble in water, which limits their mobility in the environment. Aqueous solubility of PAHs decreases approximately logarithmically as molecular mass increases, two-ring PAHs, and to a lesser extent three-ring PAHs, dissolve in water, making them more available for biological uptake and degradation
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Residue (chemistry)
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In chemistry residue is whatever remains or acts as a contaminant after a given class of events. Residue may be the material remaining after a process of preparation, separation, or purification, such as distillation, evaporation and it may also denote the undesired by-products of a chemical reaction. Toxic chemical residues, wastes or contamination from other processes, are a concern in food safety, for example, the U. S. Food and Drug Administration and the Canadian Food Inspection Agency have guidelines for detecting chemical residues that are possibly dangerous to consume. Residue may refer to an atom or a group of atoms that forms part of a molecule, in biochemistry and molecular biology, a residue refers to a specific monomer within the polymeric chain of a polysaccharide, protein or nucleic acid. One might say, This protein consists of 118 amino acid residues or The histidine residue is considered to be basic because it contains an imidazole ring. Note that a residue is different from a moiety, which, a residue might be one amino acid in a polypeptide or one monosaccharide in a starch molecule
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Toluene
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Toluene /ˈtɒljuːiːn/, also known as toluol /ˈtɒljuːɒl/, is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a benzene derivative, consisting of a CH3 group attached to a phenyl group. As such, its IUPAC systematic name is methylbenzene, Toluene is widely used as an industrial feedstock and a solvent. In 2013, worldwide sales of toluene amounted to about 24.5 billion US-dollars, as the solvent in some types of paint thinner, contact cement and model airplane glue, toluene is sometimes used as a recreational inhalant and has the potential of causing severe neurological harm. The compound was first isolated in 1837 through a distillation of oil by a Polish chemist named Filip Walter. In 1843, Jöns Jacob Berzelius recommended the name toluin, in 1850, French chemist Auguste Cahours isolated from a distillate of wood a hydrocarbon which he recognized as similar to Devilles benzoène and which Cahours named toluène. Toluene reacts as an aromatic hydrocarbon in electrophilic aromatic substitution. Because the methyl group has greater electron-releasing properties than an atom in the same position. It undergoes sulfonation to give p-toluenesulfonic acid, and chlorination by Cl2 in the presence of FeCl3 to give ortho, importantly, the methyl side chain in toluene is susceptible to oxidation. Toluene reacts with Potassium permanganate to yield benzoic acid, and with chromyl chloride to yield benzaldehyde, the methyl group undergoes halogenation under free radical conditions. For example, N-bromosuccinimide heated with toluene in the presence of AIBN leads to benzyl bromide, the same conversion can be effected with elemental bromine in the presence of UV light or even sunlight. Toluene may also be brominated by treating it with HBr and H2O2 in the presence of light. C6H5CH3 + Br2 → C6H5CH2Br + HBr C6H5CH2Br + Br2 → C6H5CHBr2 + HBr The methyl group in toluene undergoes deprotonation only with strong bases. Catalytic hydrogenation of toluene gives methylcyclohexane, the reaction requires a high pressure of hydrogen and a catalyst. Final separation and purification is done by any of the distillation or solvent extraction processes used for BTX aromatics, Toluene is so inexpensively produced industrially that it is not prepared in the laboratory. In principle it could be prepared by a variety of methods, Toluene is mainly used as a precursor to benzene via hydrodealkylation, C6H5CH3 + H2 → C6H6 + CH4 The second ranked application involves its disproportionation to a mixture of benzene and xylene. When oxidized it yields benzaldehyde and benzoic acid, two important intermediates in chemistry, in addition to the synthesis of benzene and xylene, toluene is a feedstock for toluene diisocyanate, trinitrotoluene, and a number of synthetic drugs. Toluene is a solvent, e. g. for paints, paint thinners, silicone sealants, many chemical reactants, rubber, printing ink, adhesives, lacquers, leather tanners
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Limonene
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Limonene is a colorless liquid hydrocarbon classified as a cyclic terpene. The more common d-isomer possesses a strong smell of oranges and it is used in chemical synthesis as a precursor to carvone and as a renewables-based solvent in cleaning products. The less common l-isomer is found in mint oils and has a piney, limonene takes its name from the lemon, as the rind of the lemon, like other citrus fruits, contains considerable amounts of this compound, which contributes to their odor. Limonene is a molecule, and biological sources produce one enantiomer, the principal industrial source, citrus fruit, contains d-limonene. Racemic limonene is known as dipentene, d-Limonene is obtained commercially from citrus fruits through two primary methods, centrifugal separation or steam distillation. Limonene is a relatively stable terpene and can be distilled without decomposition and it oxidizes easily in moist air to produce carveol, carvone, and limonene oxide. With sulfur, it undergoes dehydrogenation to p-cymene, limonene occurs commonly as the d or -enantiomer, but racemizes to dipentene at 300 °C. When warmed with mineral acid, limonene isomerizes to the conjugated diene α-terpinene, evidence for this isomerization includes the formation of Diels-Alder adducts between α-terpinene adducts and maleic anhydride. It is possible to effect reaction at one of the double bonds selectively, anhydrous hydrogen chloride reacts preferentially at the disubstituted alkene, whereas epoxidation with mCPBA occurs at the trisubstituted alkene. In another synthetic method Markovnikov addition of trifluoroacetic acid followed by hydrolysis of the acetate gives terpineol, limonene is formed from geranyl pyrophosphate, via cyclization of a neryl carbocation or its equivalent as shown. The final step involves loss of a proton from the cation to form the alkene, the most widely practiced conversion of limonene is to carvone. The three step reaction begins with the addition of nitrosyl chloride across the trisubstituted double bond. This species is then converted to the oxime with base, d-Limonene applied to skin may cause irritation, but otherwise appears to be safe for human uses. Limonene is common in cosmetic products, as the main odor constituent of citrus, d-limonene is used in food manufacturing and some medicines, e. g. It is added to cleaning products such as hand cleansers to give a lemon-orange fragrance, in contrast, l-limonene has a piney, turpentine-like odor. In natural and alternative medicine, d-limonene is marketed to relieve gastroesophageal reflux disease, limonene is increasingly being used as a solvent for cleaning purposes, such as the removal of oil from machine parts, as it is produced from a renewable source. It is used as a paint stripper and is useful as a fragrant alternative to turpentine. Limonene is also used as a solvent in some model airplane glues, all-natural commercial air fresheners, with air propellants, containing limonene are used by philatelists to remove self-adhesive postage stamps from envelope paper
