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M # 459. The curved surface area of a right circular cone of radius 14 centimeters is 440 square centimeters. What is the slant height of the cone? Use

233) Nitric Acid

Nitric acid (HNO3) is a colorless, liquid acid widely used in the manufacturing of explosives and fertilizers . When dissolved in water , molecules of nitric acid separate (or dissociate) into hydrogen ions (H+) and nitrate ions (NO3). The fact that nearly every nitric acid molecule dissociates is what makes nitric acid a strong acid. Nitric acid is often the starting material in the industrial production of nitrates for fertilizers.

Plants take up nitrogen from the soil in the form of ammonium ions (NH +4 ) and nitrate ions, and along with carbon containing molecules made during photosynthesis , these ions are used to synthesize amino acids, from which proteins are made. Within the past hundred years the demand for nitrogen fertilizers has grown dramatically as the need for fertilizers for agriculture has grown. The natural manner in which nitrates reach the soil involves the reaction of nitrogen gas and oxygen gas in the atmosphere to form nitrogen dioxide gas (NO2), which then reacts with atmospheric water, making nitric acid, which provides a natural source of nitrates in water and soil.

During World War I, the Germans were very interested in using ammonium nitrate (NH4NO3), a salt of nitric acid, as an explosive. Many organic nitrates such as nitroglycerine and TNT are also highly explosive. Nitric acid is made by the reaction of ammonia with oxygen gas. The nitric acid which is produced can then be used to make a variety of compounds. This is a process that has allowed large amounts of fertilizers to be produced relatively inexpensively.

Nitric acid is also formed from the reaction of nitrogen oxides produced during the combustion (burning) of fossil fuels in automobile engines. These nitrogen oxides react with water in the atmosphere and form nitric acid, one cause of acid rain . High levels of nitrates in drinking water can contribute to the formation of nitrosamines, a group of carcinogenic (cancer causing) compounds.

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Nevermind, Monox D. I-Fly! Our dear fiend, bobbym, who is not with us now, often said it happened to all, and it was nothing to worry! I too make too many mistakes when I am in a hurry!

#4257. A Human Resources Company employs 4800 people, out of which 45% are males and 60% of the males are either 25 years or older. How many males are employed in the Human Resources Company who are younger than 25 years?

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M # 458. The diameter of the base of a right circular cone is 7 centimeters and the slant height is 10 centimeters. What is the Lateral Surface Area? Use

412) Ottó Bláthy

Ottó Titusz Bláthy (11 August 1860 – 26 September 1939) was a Hungarian electrical engineer. In his career, he became the co-inventor of the modern electric transformer, the tension regulator, the AC watt-hour meter. motor capacitor for the single-phase (AC) electric motor, the turbo generator, and the high-efficiency turbo generator.

Bláthy's career as an inventor began during his time at the Ganz Works in 1883. There, he conducted experiments for creating a transformer. It is noteworthy that the name "transformer" was created by Bláthy. In 1885 the ZBD model alternating-current transformer was invented by three Hungarian engineers: Ottó Bláthy, Miksa Déri and Károly Zipernowsky. (ZBD comes from the initials of their names). In the autumn of 1889 he patented the AC watt-meter.

Early life

He attended schools in Tata and Vienna, where he obtained diploma of machinery in 1882. Between 1881 and 1883 he worked at the machinery workshop of the Hungarian Railways (MAV). Attracted by the successes of Károly Zipernowsky, he joined his team on 1 July 1883. He admitted he had learnt nothing about electrotechnics in university, so he started to learn about the theory himself. Using the Maxwell equations he invented a practical approach of sizing magnetic coils. Kapp and Hopkinson (for whom Hopkinson's law is named) only published their findings later in 1886, and 1887.

Professional life

His practical calculation method was crucial in building the first practical transformer. Based on his findings, he rebuilt his machines in 1883 and obtained better efficiency with the same weight. He was the first to investigate the heat dissipation problems of electric motors, and at that time the connection between current density and heat was determined.

At the Turin Italian National Exhibition in 1884, he saw Gaulard and Gibbs's "secondary generator"' (i.e. AC transformer) system, and he decided to improve it. Including a closed-loop magnetic field, based on the findings of Faraday, he conducted experiments with Miksa Déri in the summer of 1884 at the Ganz factory. Based on these experiments, they invented the transformer in 1885, which was unveiled at the Budapest National Exhibition in 1885.

Based on the opinions of Galileo Ferraris, the Italian government ordered a power transformer for Rome, which was installed in October 1886. Later, they designed a power plant for Tivoli, built by Ganz, with six water turbines and 5000 V, which were worked in parallel with the old steam engine generators. This was the first time in history two high-voltage power plants were connected.

His other invention, the electricity meter, was first introduced to the market in 1889. He tried to improve it and decrease its weight.

Chess works

Besides his scientific work, Bláthy is well known as an author of chess problems. He specialized in the field of very long moremovers, also known as longmovers. problems).

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#7121. Name the largest city in Canada by population.

#7122. Hoover Dam is on the banks of which river?

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#4255. Albert spends 25 percent of his salary on house rent, 5 percent on food, 15 percent on travel, 10 percent on clothes, and the remaining amount of $27,000 is saved. What is Albert's income?

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#7089. Evaluate:

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M # 456. Find the total surface area of a right circular cylinder whose height is 12 centimeters and radius 2 centimeters. Use

411) Melitta Bentz

Amalie Auguste Melitta Bentz (31 January 1873 – 29 June 1950), born Amalie Auguste Melitta Liebscher, was a German entrepreneur who invented the coffee filter in 1908.

Biography

Bentz was born in Dresden. Her father was a publisher.

As a housewife, Bentz found that percolators were prone to over-brewing the coffee, espresso-type machines at the time tended to leave grounds in the drink, and linen bag filters were tiresome to clean. She experimented with many means, but ended up using blotting paper from her son Willi's school exercise book and a brass pot perforated using a nail. When the grounds-free, less bitter coffee met with general enthusiasm, she decided to set up a business. The Kaiserliche Patentamt (Imperial Patent Office) granted her a patent on 20 June 1908, and on 15 December the company was entered into the commercial register with 73 Pfennig as "M. Bentz." After contracting a tinsmith to manufacture the devices, they sold 1,200 coffee filters at the 1909 Leipzig fair.

Her husband Hugo and their sons Horst and Willi were the first employees of the emerging company. In 1910, the company won a gold medal at the International Health Exhibition and a silver medal at the Saxon Innkeepers' Association. When the First World War erupted, metals were requisitioned for use in zeppelin construction, her husband was conscripted to Romania, paper was rationed, and coffee beans import was impossible due to the British blockade, disrupting the normal business. During this time she supported herself by selling cartons.

Continuing expansion caused them to move their business several times within Dresden. By 1928 the demand for their products was so high that the 80 workers had to work in a double-shift system. As no satisfactory production facilities could be found in Dresden, the fast-growing company moved in 1929 to Minden in eastern Westphalia. By that time 100,000 filters had been produced.

Horst took over the company, now "Bentz & Sohn," in 1930. She transferred the majority stake in Melitta-Werke Aktiengesellschaft to Horst and Willi in 1932, but kept a hand in the business, ensuring that the employees were cared for, offering Christmas bonuses, increasing vacation days from 6 to 15 days per year, and reducing the working week to 5 days. Bentz fostered the company's “Melitta Aid” system, a social fund for company employees.

After the outbreak of World War II, production stopped and the company was ordered to produce goods to aid the war effort. At the conclusion of war, the workers relocated for a time to old factories, barracks, even pubs, because the surviving portions of the main factory had been requisitioned as a provisional administration for the Allied troops, a condition that held for twelve years. By 1948, production of filters and paper had resumed, and at the time of her death at Holzhausen at Porta Westfalica in 1950, the company had reached 4.7 million Deutsche marks.

Legacy

The grandchildren of Melitta Bentz, Thomas and Stephen Bentz, still control the Melitta Group KG headquartered in Minden in the east of North Rhine-Westphalia, with some 3,300 employees in 50 companies.

231) Giraffe

Giraffe, (genus Giraffa), any of four species in the genus Giraffa of long-necked cud-chewing hoofed mammals of Africa, with long legs and a coat pattern of irregular brown patches on a light background. Giraffes are the tallest of all land animals; males (bulls) may exceed 5.5 metres (18 feet) in height, and the tallest females (cows) are about 4.5 metres. Using prehensile tongues almost half a metre long, they are able to browse foliage almost six metres from the ground. Giraffes are a common sight in grasslands and open woodlands in East Africa, where they can be seen in reserves such as Tanzania’s Serengeti National Park and Kenya’s Amboseli National Park. The genus Giraffa is made up of the northern giraffe (G. camelopardalis), the southern giraffe (G. giraffa), the Masai giraffe(G. tippelskirchi), and the reticulated giraffe (G. reticulata).

Giraffes grow to nearly their full height by four years of age but gain weight until they are seven or eight. Males weigh up to 1,930 kg (4,250 pounds), females up to 1,180 kg (2,600 pounds). The tail may be a metre in length and has a long black tuft on the end; there is also a short black mane. Both sexes have a pair of horns, though males possess other bony protuberances on the skull. The back slopes downward to the hindquarters, a silhouette explained mainly by large muscles that support the neck; these muscles are attached to long spines on the vertebrae of the upper back. There are only seven neck (cervical) vertebrae, but they are elongated. Thick-walled arteries in the neck have extra valves to counteract gravity when the head is up; when the giraffe lowers its head to the ground, special vessels at the base of the brain control blood pressure.

The gait of the giraffe is a pace (both legs on one side move together). In a gallop, it pushes off with the hind legs, and the front legs come down almost together, but no two hooves touch the ground at the same time. The neck flexes so that balance is maintained. Speeds of 50 km (31 miles) per hour can be maintained for several kilometres, but 60 km (37 miles) per hour can be attained over short distances. Arabs say of a good horse that it can “outpace a giraffe.”

Giraffes live in nonterritorial groups of up to 20. Home ranges are as small as 85 square km (33 square miles) in wetter areas but up to 1,500 square km (580 square miles) in dry regions. The animals are gregarious, a behaviour that apparently allows for increased vigilance against predators. They have excellent eyesight, and when one giraffe stares, for example, at a lion a kilometre away, the others look in that direction too. Giraffes live up to 26 years in the wild and slightly longer in captivity.

Giraffes prefer to eat new shoots and leaves, mainly from the thorny acacia tree. Cows in particular select high-energy low-fibre items. They are prodigious eaters, and a large male consumes about 65 kg (145 pounds) of food per day. The tongue and inside of the mouth are coated with tough tissue as protection. The giraffe grasps leaves with its prehensile lips or tongue and pulls them into the mouth. If the foliage is not thorny, the giraffe “combs” leaves from the stem by pulling it across the lower canine and incisor teeth. Giraffes obtain most water from their food, though in the dry season they drink at least every three days. They must spread the forelegs apart in order to reach the ground with the head.

Females first breed at four or five years of age. Gestation is 15 months, and, though most calves are born in dry months in some areas, births can take place in any month of the year. The single offspring is about 2 metres (6 feet) tall and weighs 100 kg (220 pounds). For a week the mother licks and nuzzles her calf in isolation while they learn each other’s scent. Thereafter, the calf joins a “nursery group” of similar-aged youngsters, while mothers forage at variable distances. If lions or hyenas attack, a mother sometimes stands over her calf, kicking at the predators with front and back legs. Cows have food and water requirements that may keep them away from the nursery group for hours at a time, and about half of very young calves are killed by lions and hyenas. Calves sample vegetation at three weeks but suckle for 18–22 months. Males join other bachelors when one to two years old, whereas daughters are likely to stay near the mother.

Bulls eight years and older travel up to 20 km per day looking for cows in heat (estrus). Younger males spend years in bachelor groups, where they engage in “necking” bouts. These side-to-side clashes of heads cause mild damage, and bone deposits subsequently form around the horns, eyes, and back of the head; a single lump projects from between the eyes. Accumulation of bone deposits continues through life, resulting in skulls weighing 30 kg. Necking also establishes a social hierarchy. Violence sometimes occurs when two older bulls converge on an estrous cow. The advantage of a heavy, knobbed skull is soon apparent. With forelegs braced, bulls swing their necks and club each other with their skulls, aiming for the underbelly. There have been instances of bulls being knocked off their feet or even rendered unconscious.

Paintings of giraffes appear on early Egyptian tombs; just as today, giraffe tails were prized for the long wiry tuft hairs used to weave belts and jewelry. In the 13th century, East Africa supplied a trade in hides. During the 19th and 20th centuries, overhunting, habitat destruction, and rinderpestepidemics introduced by European livestock reduced giraffes to less than half their former range. Today giraffes are numerous in East African countries and also in certain reserves of Southern Africa, where they have enjoyed somewhat of a recovery. The West African subspecies of the northern giraffe is reduced to a small range in Niger.

Giraffes were traditionally classified into one species, Giraffa camelopardalis, and then into several subspecies on the basis of physical features. Nine subspecies were recognized by coat pattern similarities; however, it was also known that individual coat patterns were unique. Some scientists contended that these animals could be divided into six or more species, since studies had shown that differences in genetics, reproductive timing, and pelage patterns (which are indicative of reproductive isolation) exist between various groups. By the 2010s mitochondrial DNA studies had determined that genetic uniquenesses brought on by the reproductive isolation of one group from another were significant enough to separate giraffes into four distinct species.

The giraffe had long been classified as a species of least concern by the International Union for Conservation of Nature (IUCN), which places all giraffes in the species G. camelopardalis. A study in 2016, however, determined that habitat loss resulting from expanding agricultural activities, increased mortality brought on by illegal hunting, and the effects of ongoing civil unrest in a handful of African countries had caused giraffe populations to plummet by 36–40 percent between 1985 and 2015, and, as of 2016, the IUCN has reclassified the conservation status of the species as vulnerable.

The only close relative of the giraffe is the rainforest-dwelling okapi, which is the only other member of the family Giraffidae. G. camelopardalis or something very similar lived in Tanzania two million years ago, but Giraffidae branched off from other members of the order Artiodactyla—cattle, antelope, and deer—about 34 million years ago.