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Bunsen burner

A Bunsen burner, named after Robert Bunsen, is a common piece of laboratory equipment that produces a single open gas flame, used for heating and combustion. The gas can be natural gas or a liquefied petroleum gas, such as propane, butane, or a mixture of both. In 1852 the University of Heidelberg promised him a new laboratory building; the city of Heidelberg had begun to install coal-gas street lighting, so the university laid gas lines to the new laboratory. The designers of the building intended to use the gas not just for illumination, but in burners for laboratory operations. For any burner lamp, it was desirable to minimize luminosity. However, existing laboratory burner lamps left much to be desired not just in terms of the heat of the flame, but regarding economy and simplicity. While the building was still under construction in late 1854, Bunsen suggested certain design principles to the university's mechanic, Peter Desaga, asked him to construct a prototype. Similar principles had been used in an earlier burner design by Michael Faraday, as well as in a device patented in 1856 by the gas engineer R. W. Elsner.

The Bunsen/Desaga design succeeded in generating a hot, non-luminous flame by mixing the gas with air in a controlled fashion before combustion. Desaga created adjustable slits for air at the bottom of the cylindrical burner, with the flame igniting at the top. By the time the building opened early in 1855. Two years Bunsen published a description, many of his colleagues soon adopted the design. Bunsen burners are now used in laboratories all around the world; the device in use today safely burns a continuous stream of a flammable gas such as natural gas or a liquefied petroleum gas such as propane, butane, or a mixture of both. The hose barb is connected to a gas nozzle on the laboratory bench with rubber tubing. Most laboratory benches are equipped with multiple gas nozzles connected to a central gas source, as well as vacuum and steam nozzles; the gas flows up through the base through a small hole at the bottom of the barrel and is directed upward. There are open slots in the side of the tube bottom to admit air into the stream using the Venturi effect, the gas burns at the top of the tube once ignited by a flame or spark.

The most common methods of lighting the burner are using a spark lighter. The amount of air mixed with the gas stream affects the completeness of the combustion reaction. Less air yields an incomplete and thus cooler reaction, while a gas stream well mixed with air provides oxygen in a stoichiometric amount and thus a complete and hotter reaction; the air flow can be controlled by opening or closing the slot openings at the base of the barrel, similar in function to the choke in a carburettor. If the collar at the bottom of the tube is adjusted so more air can mix with the gas before combustion, the flame will burn hotter, appearing blue as a result. If the holes are closed, the gas will only mix with ambient air at the point of combustion, that is, only after it has exited the tube at the top; this reduced mixing produces an incomplete reaction, producing a cooler but brighter yellow, called the "safety flame" or "luminous flame". The yellow flame is luminous due to small soot particles in the flame, which are heated to incandescence.

The yellow flame is considered "dirty" because it leaves a layer of carbon on whatever it is heating. When the burner is regulated to produce a hot, blue flame, it can be nearly invisible against some backgrounds; the hottest part of the flame is the tip of the inner flame, while the coolest is the whole inner flame. Increasing the amount of fuel gas flow through the tube by opening the needle valve will increase the size of the flame. However, unless the airflow is adjusted as well, the flame temperature will decrease because an increased amount of gas is now mixed with the same amount of air, starving the flame of oxygen; the burner is placed underneath a laboratory tripod, which supports a beaker or other container. The burner will be placed on a suitable heatproof mat to protect the laboratory bench surface. A Bunsen burner is used in microbiology laboratories to sterilise pieces of equipment and to produce an updraft that forces airborne contaminants away from the working area. Other burners based on the same principle exist.

The most important alternatives to the Bunsen burner are: Teclu burner – The lower part of its tube is conical, with a round screw nut below its base. The gap, set by the distance between the nut and the end of the tube, regulates the influx of the air in a way similar to the open slots of the Bunsen burner; the Teclu burner provides better mixing of air and fuel and can achieve higher flame temperatures than the Bunsen burner. Meker burner – The lower part of its tube has more openings with larger total cross-section, admitting more air and facilitating better mixing of air and gas; the tube is wider and its top is covered with a wire grid. The grid separates the flame into an array of smaller flames with a common external envelope, prevents flashback to the bottom of the tube, a risk at high air-to-fuel ratios and limits the maximum rate of air intake in a conventional Bunsen burner. Flame temperatures of up to 1,100–1,200 °C are achievable if properly used; the flame burns without noise, unlike the Bunsen or Teclu burners.

Tirrill burner – The base of the burner has a needle valve which allows the regulation of gas intake directly from the Burner, rather than from the gas source. Maximum temperature of flame can reach 1560 °C. Alcohol burner Heating mantle

Kosmos 1217

Kosmos 1217 was a Soviet US-K missile early warning satellite, launched in 1980 as part of the Soviet military's Oko programme. The satellite was designed to identify missile launches using optical telescopes and infrared sensors. Kosmos 1217 was launched from Site 41/1 at Plesetsk Cosmodrome in the Russian SSR. A Molniya-M carrier rocket with a 2BL upper stage was used to perform the launch, which took place at 10:53 UTC on 24 October 1980; the launch placed the satellite into a molniya orbit. It subsequently received its Kosmos designation, the international designator 1980-085A; the United States Space Command assigned it the Satellite Catalog Number 12032. 1980 in spaceflight List of Kosmos satellites List of Oko satellites List of R-7 launches

Public housing estates in Cheung Sha Wan

The following is an overview of Public housing estates in Cheung Sha Wan, Hong Kong, including Home Ownership Scheme, Green Form Subsidised Home Ownership Scheme, Private Sector Participation Scheme, Tenants Purchase Scheme estates. Historians suggested there were inhabitants settled in this area during Eastern Han Dynasty, as an Eastern Han tomb was discovered in the year 1955, the Eastern Han tomb now become Lee Cheng Uk Museum when Lee Cheng Uk Estate was built; the original Cheung Sha Wan Estate opened between 1963 and 1964 as the Cheung Sha Wan Government Low Cost Housing Estate. It was renamed following the 1973 establishment of the Housing Authority. All thirteen blocks of this estate were demolished in 2001 as part of the Comprehensive Redevelopment Programme, announced 1995. Most displaced residents were moved to the nearby Fortune Estate. A new estate opened in 2013 bearing the same name, it sits just north of the original Cheung Sha Wan Estate site, on the site of the former Cheung Sha Wan Police Married Quarters.

It is made up of two public rental blocks and an auxiliary facilities block linked to Un Chau Estate by a walkway spanning Cheung Sha Wan Road. The site of the original Cheung Sha Wan Estate was leased to the Asia Golf Club driving range; the golf club has since closed and a new public housing estate is under construction on the site. This new estate is called Lai Chi Estate. Fortune Estate is located opposite near Cheung Sha Wan Station; the site of Fortune Street Temporary Housing Area, the estate consists of three residential buildings built in 2001 to settle the residents affected by the redevelopment of Cheung Sha Wan Estate, Tai Hang Tung Estate and Un Chau Estate. Hang Chun Court is a HOS court in Cheung Sha Wan, next to Fortune Estate. Like Fortune Estate, Hang Chun Court was the site of Fortune Temporary Housing Area, it has two blocks built in 2001. Hoi Lai Estate was built on the reclaimed land of south Cheung Sha Wan, near Lai Chi Kok Station and four private housing estates, namely Aqua Marine, Banyan Garden, Liberté and The Pacifica.

The estate consists of 12 residential buildings and a shopping centre completed between 2004 and 2005. It was planned for HOS court. Hoi Lok Court is a Home Ownership Scheme court in Lai Ying Street, Cheung Sha Wan reclaimed area of Sham Shui Po District near MTR Nam Cheong Station and Hoi Ying Estate, it comprises five 40-to-42-storey blocks with 2,522 flats. The flats were sold in 2018 at prices from HK$2.17M to HK$4.68M, after the revision from the previous 70% of the market flat prices to 52% announced by Carrie Lam, Chief Executive of Hong Kong. The court completed in 2019. Hoi Tak Court is a Home Ownership Scheme court in Fat Tseung Street West, Cheung Sha Wan reclaimed area of Sham Shui Po District, near MTR Nam Cheong Station and Fu Cheong Estate, it comprises one block with 814 flats. It was arranged for sale in 2018 and is expected to complete in late 2020. Lei Cheng Uk Estate is a mixed public and TPS estate in Lei Cheng Uk, downhill of Cheung Sha Wan near So Uk Estate, it is adjacent to the Lei Cheng Uk Han Tomb Museum.

Since the redevelopment in the 1980s, the estate consists of 10 residential buildings completed in 1984, 1989 and 1990 respectively. In 2002, some of the flats were sold to tenants through Tenants Purchase Scheme Phase 5; the estate is now managed by Hong Kong Housing Society. Po Hei Court is a HOS court in Cheung Sha Wan, next to Lei Cheng Uk Han Tomb Museum and Lei Cheng Uk Estate, it consists of 2 blocks built in 1993. Po Lai Court is a HOS court in Cheung Sha Wan, next to Po Hei Court, it consists of three blocks built in 1987. So Uk Estate is situated in a downhill in Cheung Sha Wan; the estate was built alongside of squatter areas, demolished for the construction of the estate of 16 blocks in 1960. Unlike many public housing estates built afterwards, the architectural design of the estates is unique in Hong Kong; the "houses" were named after varieties of flowers. There are 5,316 flats in the estate, with capacity of 15,200. High maintenance cost made the Hong Kong Housing Authority decide to demolish it in 2008 and 2011 in two phases, residents will be relocated to Un Chau Estate Phases 2, 4, 5 in Sham Shui Po.

Un Chau Estate, or Un Chau Street Estate, is a redeveloped public estate on reclaimed land of Cheung Sha Wan located between Un Chau Street and Cheung Sha Wan Road, next to Cheung Sha Wan Station. It consists of 10 residential buildings completed in 1998, 1999 and 2008, which were developed into 4 phases. Phase 5 is under development on the site of former Cheung Sha Wan Factory Estate. Public housing in Hong Kong List of public housing estates in Hong Kong

1730 Valparaíso earthquake

The 1730 Valparaíso earthquake occurred at 04:45 local time on July 8. It had an estimated magnitude of 9.1 and triggered a major tsunami with an estimated magnitude of Mt=8.75, that inundated the lower parts of Valparaíso. The earthquake caused severe damage from La Serena to Chillan, while the tsunami affected more than 1,000 km of Chile's coastline; the earthquake took place along the boundary between the Nazca and South American tectonic plates, at a location where they converge at a rate of seventy millimeters a year. Chile has been at a convergent plate boundary that generates megathrust earthquakes since the Paleozoic. In historical times the Chilean coast has suffered many megathrust earthquakes along this plate boundary, including the strongest earthquake measured. Most the boundary ruptured in 2010 in central Chile; the earthquake caused severe damage over a wide area, Valparaíso, Illapel and Tiltil were all affected. The parish church in La Serena was destroyed. Only a few deaths were recorded due to the earthquake because a strong foreshock had caused people to leave their homes.

The same is true for the following tsunami with the inhabitants running to higher ground after seeing the water recede, so that only a few were killed. At about 01:00 local time in Santiago, there was a strong earthquake, followed by several smaller tremors; the main shock occurred at 4:45 local time. A 350–550 km long rupture has been estimated for this event, from the extent of severe damage; the tsunami occurred after the mainshock, with a maximum run-up height recorded at Concepción of 16 m. It was observed at Callao, Peru and in Honshu, Japan where fields were flooded in Rikuzen and the Oshika Peninsula. List of earthquakes in Chile List of historical earthquakes

Botanical Latin

Botanical Latin is a technical language based on New Latin, used for descriptions of botanical taxa. Until 2012, International Code of Botanical Nomenclature mandated Botanical Latin to be used for the descriptions of most new taxa, it is still the only language other than English accepted for descriptions. The names of organisms governed by the Code have forms based on Latin. Botanical Latin is a written language, it includes taxon names derived from any language or arbitrarily derived, there is no single consistent pronunciation system. When speakers of different languages use Botanical Latin in speech, they use pronunciations influenced by their own languages, or, notably in French, there may be variant spellings based on the Latin. There are at least two pronunciation systems used for Latin by English speakers. All of these systems, will be unsustainable across the spectrum of botanical names. Augustin Pyramus de Candolle described the language in 1880: C'est le latin arrangé par Linné à l'usage des descriptions et, j'oserai dire, à l'usage de ceux qui n'aiment ni les complications grammaticales, ni les phrases disposées sens desus dessous."

De Candolle estimated that to learn Botanical Latin would take three months' work for an English speaker not familiar with any language of Latin origin, one month for an Italian. William T. Stearn wrote: Botanical Latin is best described as a modern Romance language of special technical application, derived from Renaissance Latin with much plundering of ancient Greek, which has evolved since 1700 and through the work of Carl Linnaeus, to serve as an international medium for the scientific naming of plants in all their vast numbers and manifold diversity; these include many thousands of plants unknown to the Greeks and Romans of classical times and for which names have had to be provided as a means of reference. Their description necessitates the recording of structures too small for comprehension by the naked eye, hence unknown to the ancients and needing words with precise restricted applications foreign to classical Latin. Latin names of organisms are used in English without alteration, but some informal derivatives are used as common names.

For example, the -idae ending of subclass names is changed to -ids. The -ids common names have, however been adopted as rankless clade names, sometimes containing further -ids clade names, so that, for example, in the APG IV classification, rosids contain both fabids and malvids. More extensive modifications to the spelling and pronunciation are used in some other languages. French organism names are gallicized. For example: Chlorophyceae becomes Chlorophycées; the Classical Latin alphabet consisted of 21 letters, to which w, y, z were added, the vowel/consonant pairs i and j, u and v, were separated. This 26-letter alphabet is used for taxon names in Botanical Latin. Diacritics are not used in names, a dieresis is considered an optional mark that does not affect spelling; some English speakers, some speakers of other languages, use the reconstructed pronunciation guide for Classical Latin when speaking Botanical Latin. Latin names pronounced by gardeners and English botanists follow a system close to English.

It differs from Classical pronunciation, from Ecclesiastical Latin pronunciation. Every vowel is pronounced, except diphthongs. In classical Latin words of several syllables the stress falls on the syllable next to the last one when this syllable is long... e.g. for-mō'-sus, or when two consonants separate the two last vowels, e.g. cru-ěn'-tus... on the last syllable but two when the last but one is short, e.g. flō-ri-dus. "These rules cannot satisfactorily be applied to all generic names and specific epithets commemorating persons. About 80 per cent of generic names and 30 per cent of specific epithets come from languages other than Latin and Greek. A simple and consistent method of pronouncing them does not exist." The rules create difficulties with the -ii and -iae endings derived from personal names, because the stress falls in a place, not usual for those names. The following table is simplified from Stearn 1992; the pronunciation transcriptions for medical terminology in major medical dictionaries, such as Dorland’s Illustrated Medical Dictionary and Stedman's Medical Dictionary, match these values.

An example from gracilis,-is,-e "slender", "thin", "graceful" A Grammatical Dictionary of Botanical Latin International Code of Nomenclature for algae and plants 2018 Stearn, W. T. "Botanical Latin", Timber Press, Portland Oregon. ISBN 9780881926279 Backer, C. A. Verklarend woordenboek der wetenschappelijke namen van de in Nederland en Nederlandsch-Indië in het wild groeiende en in tuinen en parken gekweekte varens en hoogere planten. Brown, R. W.. The Composition of Scientific Words. Washington, D. C.: Smithsonian Institution Pre

Gold-dipped roses

Gold-dipped roses, or gold-trimmed roses, are real roses that are cut and preserved in a protective shell of gold to make them last a long time. These roses are given as gifts on special occasions like Mother's Day, Valentine’s Day, wedding anniversaries and other celebrations and events; the idea behind gold-dipped roses is to preserve the elegance and beauty of a rose forever in a metal, just as exquisite and valuable as the rose itself, to make a permanent and lasting expression of the emotions expressed by the giving of roses. The concept of gold-dipped roses has been around for quite a long time. However, the techniques of making a rose have improved, paying special attention to intricate details, so that all the features of a rose are enhanced and beautified. If the process of gold-dipping, the rose and the gold used are of good quality, the gold-dipped rose can be made to last a lifetime. Other varieties of dipped roses include silver and tin roses. Petals and rose orchids are dipped in precious metals for preservation and decoration.

Different companies have different techniques and procedures for making gold-dipped roses, most of the steps involved are patented by each company and are trade secrets. Dipping or plating a rose is a time-consuming and painstaking process that involves multiple steps and weeks to prepare the finished product; some companies claim that it requires 60 steps and 3 months of delicate processing to make a gold-dipped rose, while others profess that it requires 30 days to make the end product. However, the basic procedure for small-scale processing, is the same. At the commercial level, several companies use the process of electroplating the rose with gold for a more durable and professional look. Simplified steps of the process are as below: Select a healthy and purpose-grown rose, not yet bloomed. Hand paint or spray the rose with lacquer or an electrophoresing chemical so that the metal will stick to it. Let the chemical dry; this may take a day. Melt the gold, dip the rose in it bud-first, holding by the stem, for between 60 and 90 seconds, depending upon the desired thickness of the metal.

If a light coating is required, dip it for less than 60 seconds, or for a heavier coating, let it dip for more than 90 seconds. An alternative method, used for commercial processing, is complete electroplating of the rose first with metals such as copper, a final coating of gold. Let it dry till a hard shell is formed, which may take a couple of days, depending on factors like wind and humidity; the idea is to preserve the delicacy and pattern of the rose so that it is evident through the gold plating. Gold-dipped roses are available for anywhere between $69 to $299, depending on the technique and vendors, the karat of the gold, used for dipping, the thickness of the coating; some cheaper roses are coated with tin and lightly sprayed with gold of a lesser quality, like 10 karat. Good quality roses are dipped in 24K gold, hence are expensive