Microelectromechanical systems written as micro-electro-mechanical systems and the related micromechatronics and microsystems constitute the technology of microscopic devices those with moving parts. They merge at the nanoscale into nanoelectromechanical systems and nanotechnology. MEMS are referred to as micromachines in Japan and microsystem technology in Europe. MEMS are made up of components between 1 and 100 micrometers in size, MEMS devices range in size from 20 micrometres to a millimetre, although components arranged in arrays can be more than 1000 mm2, they consist of a central unit that processes data and several components that interact with the surroundings. Because of the large surface area to volume ratio of MEMS, forces produced by ambient electromagnetism, fluid dynamics are more important design considerations than with larger scale mechanical devices. MEMS technology is distinguished from molecular nanotechnology or molecular electronics in that the latter must consider surface chemistry.
The potential of small machines was appreciated before the technology existed that could make them. MEMS became practical once they could be fabricated using modified semiconductor device fabrication technologies used to make electronics; these include molding and plating, wet etching and dry etching, electrical discharge machining, other technologies capable of manufacturing small devices. MEMS technology has roots in the silicon revolution, which can be traced back to two important silicon semiconductor inventions from 1959: the monolithic integrated circuit chip by Robert Noyce at Fairchild Semiconductor, the MOSFET by Mohamed M. Atalla and Dawon Kahng at Bell Labs. MOSFET scaling, the miniaturisation of MOSFETs on IC chips, led to the miniaturisation of electronics; this laid the foundations for the miniaturisation of mechanical systems, with the development of micromachining technology based on silicon semiconductor technology, as engineers began realizing that silicon chips and MOSFETs could interact and communicate with the surroundings and process things such as chemicals and light.
One of the first silicon pressure sensors was isotropically micromachined by Honeywell in 1962. An early example of a MEMS device is the resonant-gate transistor, an adaptation of the MOSFET, developed by Harvey C. Nathanson in 1965. Another early example is the resonistor, an electromechanical monolithic resonator patented by Raymond J. Wilfinger between 1966 and 1971. During the 1970s to early 1980s, a number of MOSFET microsensors were developed for measuring physical, chemical and environmental parameters. There are two basic types of MEMS switch technology: ohmic. A capacitive MEMS switch is developed using a moving plate or sensing element, which changes the capacitance. Ohmic switches are controlled by electrostatically controlled cantilevers. Ohmic MEMS switches can fail from metal fatigue of the MEMS actuator and contact wear, since cantilevers can deform over time; the fabrication of MEMS evolved from the process technology in semiconductor device fabrication, i.e. the basic techniques are deposition of material layers, patterning by photolithography and etching to produce the required shapes.
Silicon is the material used to create most integrated circuits used in consumer electronics in the modern industry. The economies of scale, ready availability of inexpensive high-quality materials, ability to incorporate electronic functionality make silicon attractive for a wide variety of MEMS applications. Silicon has significant advantages engendered through its material properties. In single crystal form, silicon is an perfect Hookean material, meaning that when it is flexed there is no hysteresis and hence no energy dissipation; as well as making for repeatable motion, this makes silicon reliable as it suffers little fatigue and can have service lifetimes in the range of billions to trillions of cycles without breaking. Semiconductor nanostructures based on silicon are gaining increasing importance in the field of microelectronics and MEMS in particular. Silicon nanowires, fabricated through the thermal oxidation of silicon, are of further interest in electrochemical conversion and storage, including nanowire batteries and photovoltaic systems.
Though the electronics industry provides an economy of scale for the silicon industry, crystalline silicon is still a complex and expensive material to produce. Polymers on the other hand can be produced in huge volumes, with a great variety of material characteristics. MEMS devices can be made from polymers by processes such as injection molding, embossing or stereolithography and are well suited to microfluidic applications such as disposable blood testing cartridges. Metals can be used to create MEMS elements. While metals do not have some of the advantages displayed by silicon in terms of mechanical properties, when used within their limitations, metals can exhibit high degrees of reliability. Metals can be deposited by electroplating and sputtering processes. Used metals include gold, aluminium, chromium, tungsten, p
Raveneau de Lussan was a French buccaneer. He belonged to a noble but impoverished family, embraced a military career at the age of 14. In 1679 he embarked for Santo Domingo in search of fortune, but was unsuccessful, joined the buccaneers under Laurens de Graaf, sailing from Petit-Goâve, 22 November 1684, he soon left de Graaf at the head of a band of his own, in 1685 pillaged the town of El Realejo. In 1686 his band took part in the capture of Grenada, not finding the booty they expected, set fire to the city. After this Lussan separated from the English pirates, but he joined them again for the purpose of attacking Guayaquil, which they took with much booty. Lussan and a part of his followers sailed for Tehuantepec, which they captured, went as far north as Acapulco, they returned to Mapala, a port north of El Realejo, deliberated on the route they should take to reach the Antilles. It was agreed to march to Nueva Segovia, a town situated on the Coco River, which empties into the Atlantic. Of this expedition Voltaire said: "The retreat of the ten thousand will always be more celebrated, but is not to be compared to it."
Lussan formed four companies, of seventy men each, made them swear to observe the severest discipline. On 2 January 1688, after praying together, sinking their boats for fear they might fall into the power of the Spaniards, they began their march, in ten days, during which they were constantly engaged in fighting superior numbers, they reached Nueva Segovia. One evening, in a defile surrounded by rocks of great height on which the Spaniards had intrenched themselves, the buccaneers sought hopelessly for a way of escape. Lussan proposed that, leaving eighty men to guard the sick, they should get in the rear of the mountains and surprise the enemy, his advice was adopted when their case became desperate. They found a path which led behind the mountains, favored by a thick fog, they forced the intrenchments of the Spaniards and put them to flight. After this victory they chanted a Te Deum, they descended the Yara on the wretched boats of the country, came in sight of Cape Gracias a Dios on 9 February.
Lussan embarked on an English lugger on 14 February, reached Santo Domingo on 6 April. He had marched nearly 1,000 miles harassed by the Spaniards, although the distance from the point where he started to that which he wished to reach was but 240 miles in a straight line. Lussan published Journal du voyage fait à la mer du Sud avec les flibustiers de l'Amérique, it was dedicated to the minister of the navy, who, in common with most Frenchmen of the time, appeared to consider the exploits of Lussan worthy of approval. Although the work is confused, it contains curious and interesting details on the productions and manners of the natives of the countries he visited. Wilson, J. G.. "Lussan, Raveneau de". Appletons' Cyclopædia of American Biography. New York: D. Appleton
Volcán San Cristóbal is the highest volcano in Nicaragua at 1,745 m. Located near to the northwest corner of the country, it forms a backdrop to the city of Chichigalpa, Chinandega, it is among the most active volcanos in Nicaragua. San Cristóbal is part of a 5-member volcanic complex. Chonco lies 4 km to the west, Moyotepe 4 km to the north east. Joined to the volcano's eastern flank is Volcán Casitas, which buried a village with a catastrophic landslide in 1998; the scars from said landslide are still visible today. La Pelona is located on the eastern end of the complex. San Cristóbal is the youngest volcano in its complex, it is a nearly symmetrical stratovolcano, rising in a distinctive cone shape. The SW slope is the longest, the crater rim on that side rises 140 m above the NE end due to prevailing trade winds that distribute tephra to the SW; the crater is 500 × 600 m in size. While the volcano was at one point covered in tropical forests, the large quantities of gas and smoke that it emits have killed off much of the vegetation.
1685: Erupted enough to merit preservation in historical accounts. August 1919: Produced loud noises and light tremors that were felt in surrounding areas. May 1971: Produced bangs and explosions. March 1976: Produced a high, continuous column of smoke, several light tremors, explosions that occurred every three minutes. C. December 1986: Marked expulsion of gases c. January 1987: Expelled large quantities of gas. May 1997: Entered into a new eruptive period, expelling gases and sand, producing light tremors. December 1999: Expelled gas and sand. May, August 2001: Reactivated. April 2006: Moderate phreatic eruption. July 2008: Rumbled with a series of small explosions, expelled gas. September 2009: Explosion and moderate ash expulsion. September 2012: Three big explosions, expelled gas and sand to 5,000 metres, following the 2012 Costa Rica earthquake. December 25, 2012 and continuing into 2013: elevated seismic activity and multiple eruptions over the next few days. April 11, 2014: Gas plume that may contain ash drifted West about 20 km.
July 20, 2014: Two explosions that occurred at 1:30 P. M. and 2:13 P. M. local time produced small plumes of ash. San Cristóbal remains quite active, continuously expelling copious amounts of smoke; as recent as September 2009, it was reported. In September 2012 it erupted again, spewing ash up to four kilometres into the atmosphere, resulting in the evacuation of around 3000 people in the surrounding area. A further eruption took place, starting on the 25th of December 2012 and continuing into 2013, causing the evacuation of hundreds of locals. List of volcanoes in Nicaragua
The impulse for creation of centres of technical training came from the British rulers of India, it arose out of the necessity for the training of overseers for construction and maintenance of public buildings, roads and ports, for the training of artisans and craftsmen for the use of instruments, apparatus needed for the army, the navy, the survey department. While superintending engineers were recruited from Britain, lower grade craftsmen and sub-overseers were recruited locally; the necessity to make them more efficient, led to the establishment of industrial schools attached to the Ordnance Factories Board and other engineering establishments. The first engineering college was established in present day Uttarakhand at Roorkee in the year 1847 for the training of Civil Engineers. Thomason College of Civil Engineering as it was called, made use of the large workshops and public buildings there that were erected for the Upper Ganges Canal; the college was converted to the University of Roorkee in 1948 and upgraded to the Indian Institute of Technology, Roorkee in 2001.
In July 1854, College of Engineering, Pune's precursor, The Poona Engineering Class and Mechanical School was opened, with an aim to provide suitable learning to the subordinate officers in the Public Works Department. In June 1865 Mr. Theodore Cooke, M. A, who held that appointment for 28 years was appointed Principal; the foundation stone of the new college was laid by the Governor, Sir Bartle Frere, on 5 August 1865. College was affiliated to University of Bombay in 1866. In 1868 the College moved to the New Buildings; the college was divided into three departments for unmatriculated students. In 1879 two new classes, an Agricultural class and a Forest class, were added to the college, the name of the college was changed from " The Poona Civil Engineering College " to " The College of Science"; the credit for most of the civil infrastructure in India goes to the alumni of COEP, including Bharat Ratna Sir M. Visvesvarayya, in whose honor "Engineers Day" is celebrated. In pursuance of the Government policy, three Engineering Colleges were opened by about 1856 in the three Presidencies.
In Bengal, a College called the Calcutta Civil Engineering College was opened at the Writers' Buildings in November 1856. With the establishment of University of Calcutta on 24 January 1857, the college was affiliated to this university in May 1857. In 1865, the college merged with Presidency College and from 1865 to 1869 the college functioned as the Civil Engineering Department of Presidency College. In 1880, the college was shifted to its present campus at Shibpur and was christened the Government College, Howrah, in the premises of Bishop's College. On 12 February 1920 the name was changed to Shibpur; the word Shibpur was deleted on 24 March 1921 and it became Bengal Engineering College. The college was subsequently rechristened Bengal Engineering and Science University and upgraded to the Indian Institute of Engineering Science and Technology, Shibpur in 2014. In the Madras Presidency, the industrial school attached to the Gun Carriage Factory became the College of Engineering and was affiliated to the University of Madras in 1858.
The Banaras Engineering College was established at Varanasi in the year 1919. The college was rechristened as the Institute of Technology, Banaras Hindu University in 1968; the college was upgraded to the Indian Institute of Technology, Varanasi in 2012. The British opened Harcourt Butler Technological Institute, Kanpur for chemical sciences in 1921 in the United Provinces, now Uttar Pradesh, it is now called the Harcourt Butler Technical University. Indian School of Mines, Dhanbad was established by British Indian Government on the lines of the Royal School of Mines and was formally opened on 9 December 1926 by Lord Irwin, the Viceroy of India; the college was subsequently called the Indian School of Mines University for a while before the word University was dropped from its name. The college was upgraded to the Indian Institute of Technology, Dhanbad in 2016. In 1947 when India became independent, there were 36 institutions for first-degree engineering education, with an annual intake of about 2500 students.
Laxminarayan institute of technology,Nagpur. Started in 1943,it is chemical engineering college. ^B Have been upgraded to Indian Institutes of Technology. A Raised to degree standard
Ruth Rasnic is an Israeli social and political activist in the struggle against domestic violence in Israel, a writer and a translator. Rasnic won the Israel Prize in 2009 for her life's work. Rasnic spent her childhood there and in Tel Aviv. At the age of 14 she joined the Etzel, two years joined a youth settlement group at kibbutz Ruhama, she served in the Israeli Air Force, worked at the Israeli embassy in London. She returned to Israel after the death of her younger brother in the line of duty. In 1977, she established L. O. Combat Violence Against Women, a non-profit organization dedicated to fighting violence against women, of which she was the paid executive director for 34 years, from 1977 to 2011, a year in which she became a volunteer. Rasnic was one of the founders of the liberal Ratz political party, served as the party's representative in Na'amat from 1981 to 1996. In 1986, Rasnic joined the founders of the Israel Women's Network, headed by Prof. Alice Shalvi, as a member and organizer.
In 1991 and in 2006, Rasnic was recognized by the Israel Woman's Network for her contributions. In 2000, she was chosen to light a torch in the annual ceremony at the Mount Herzl military cemetery, closing Israel's Memorial Day for fallen soldiers, an honor bestowed on valued members of society. In 2008, she was appointed by Prime Minister Ehud Olmert to his advisory council for women's stature. In 2009, Rasnic was awarded the Israel Prize for her lifetime achievement & special contribution to society and the State. List of Israel Prize recipients Women's Spirit Feminism in Contemporary Israel Women in Israel
Pakistan Museum of Natural History, established in 1976, is a public natural history museum situated in Islamabad, the federal capital of Pakistan. It has exhibits and galleries which display and provide information about the ecology and palaeontology of the country; the museum houses a collection of over 300,000 objects. The museum acts as a research center and works with the Lok Virsa Museum; the museum is open to public everyday, from 10 am to 5 pm. The museum is managed by the Pakistan Science Foundation, under the Ministry of Science and Technology of which Fawad Chaudhry is minister from 18 April 2019. Biological gallery - displays and discusses wild flora and fauna, portrayed in their respective habitats. Ecological gallery - an educational section where ecological cycles and environmental problems are discussed through visuals and audios. Gemstones gallery - shows a variety of gems in-the-raw as well as cut and polished forms. Palaeontology gallery - displays fossils along with their studies.
Anthropology is discussed through paintings and writings, including a skull of Australopithecus. Wall paintings depict the pre-historic era. Tethys gallery - provides information about oceanology, petrology and mineralogy of Pakistan, it displays a three-dimensional diorama of seascapes as well as a skeleton of a whale. Different aspects of the salt Range are studied in detail. Virtual Orientation Gallery - it allows visitors to take virtual tours of all the above galleries without walking around the entire museum; this new gallery was introduced in 2016. Dr Muhammad Rafique - Director General of the Museum in 2017 Abid Hussain - Private Secretary Botanical Sciences Division Syed Anil Gilani - Associate Curator Sumaira Sehreen – Research Associate Rizwana Khanum – Research Associate Earth Sciences Division Aamir Yaseen – Associate Curator Khalid Ahmed Mirani – Associate Curator Zoological Sciences Division Muhammad Rafique - Director Khalid Mahmood - Curator Muhammad Asif Khan - Associate Curator Muhammad Abbas - Associate Curator Public Services Division Lal Shah – Director Rahat Saeed – Operational Manager at the museum in 2016 PMNH acquired a large whale shark which landed at Karachi Fish Harbour in 2012, according to PMNH.
This whale shark weighed 16 tonnes. Its liver weighed about 800 kg, the stomach was about 600 kg, the ovary had a weight of 120 kg and had about 1500 eggs; the shark was seen on February 6, 2012, in the Gora Bari area, in the Pakistani territory of the Arabian Sea, by local fishermen. According to them, it was alive at that time but died before they started hauling it towards the sea shore; the fish was brought to Karachi Fish Harbour on February 7, 2012, auctioned for Rs. 200,000. The Museum mounted it as a dried specimen. However, due to the lack of professional taxidermy skills and poor maintenance, the specimen is perishing despite being repainted and repaired several times. Natural history of Indian sub-continent Wildlife of Pakistan Lok Virsa Museum List of museums in Pakistan