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#1 Re: Ganesh's Puzzles » Oral puzzles » Today 13:51:42

Hi,

The solution #3838 is correct. Excellent, Monox D. I-Fly!

#3839. If the arithmetic mean of 7, 8, x, 11, 14 is x, find the value of x.

#2 Re: Ganesh's Puzzles » Oral puzzles » Today 00:31:11

Hi,

#3838. If 35 is removed by the data : 30, 34, 35, 36, 37, 38, 39, 40, then them median decreases by how much?

#3 Re: This is Cool » Miscellany » Yesterday 19:43:39

32) Gulf of Mexico

Gulf of Mexico, Spanish Golfo de México, partially landlocked body of water on the southeastern periphery of the North American continent. It is connected to the Atlantic Ocean by the Straits of Florida, running between the peninsula of Florida and the island of Cuba, and to the Caribbean Sea by the Yucatán Channel, which runs between the Yucatán Peninsula and Cuba. Both of these channels are about 100 miles (160 km) wide. The gulf’s greatest east-west and north-south extents are approximately 1,100 and 800 miles (1,800 and 1,300 km), respectively, and it covers an area of some 600,000 square miles (1,550,000 square km). To the northwest, north, and northeast it is bounded by the southern coast of the United States, while to the west, south, and southeast it is bounded by the east coast of Mexico.

Physical Features

Physiography and geology

The Gulf of Mexico consists of several ecological and geologic provinces, chief of which are the coastal zone, the continental shelf, the continental slope, and the abyssal plain. The coastal zone consists of tidal marshes, sandy beaches, mangrove-covered areas, and many bays, estuaries, and lagoons. The continental shelf forms an almost continuous terrace around the margin of the gulf; its width varies from a maximum of more than 200 miles (320 km) to a minimum of about 25 miles (40 km). Off the west coast of Florida as well as off the Yucatán Peninsula, the continental shelf consists of a broad area composed primarily of carbonate material. The remainder of the shelf consists of sand, silt, and clay sediments. On the shelf and on the slope that dips downward to the abyssal plain, buried salt domes occur at various depths; economically important deposits of oil and natural gas are associated with them. The abyssal plain, which forms the floor of the gulf, consists of a large triangular area near the centre, bounded by abrupt fault scarps toward Florida and the Yucatán Peninsula and by more gentle slopes to the north and west. The basin is unusually flat, having a gradient of only about 1 foot (0.3 metre) in every 8,000 feet (2,440 metres). The deepest point is in the Mexico Basin (Sigsbee Deep), which is 17,070 feet (5,203 metres) below sea level. From the floor of the basin rise the Sigsbee Knolls, some of which attain heights of 1,300 feet (400 metres); these are surface expressions of the buried salt domes.

Hydrology

The southeastern portion of the gulf is traversed by a riverlike current that becomes the main source of the North Atlantic Gulf Stream; this is the principal current moving oceanic waters through the gulf. Water from the Caribbean enters through the Yucatán Channel, the floor of which forms a sill (submarine ridge between basins) at about 1 mile (1.6 km) beneath the surface, and flows out in a clockwise direction via the Straits of Florida. Meandering masses of water, called loop currents, break off from the main stream and also move clockwise into the northeastern part of the gulf. Both seasonal and annual variations occur in these loop currents. A less well-defined pattern exists in the western gulf. There the currents are relatively weak, varying appreciably in intensity with season and location. There is extreme variability in both current direction and speed on the continental shelf and in the coastal waters of the gulf, where currents are subjected to seasonal and annual variations caused not only by major circulation patterns but also by changes in the prevailing wind direction.

The various rivers flowing into the Gulf of Mexico drain a land area roughly double that of the gulf, and the salinity of the gulf is subject to wide variations. In the open gulf the salinity is comparable to that of the North Atlantic, about 36 parts per thousand. This proportion, however, varies markedly during the year in coastal waters, particularly near the outflow of the broad delta region of the Mississippi River. During periods when the volume of the Mississippi’s flow is greatest, salinities as low as 14 to 20 parts per thousand occur as far as some 20 to 30 miles (30 to 50 km) offshore.

Sea surface temperatures in February vary between 64 °F (18 °C) in the northern gulf and 76 °F (24 °C) off the Yucatán coast. In the summer, surface temperatures of about 90 °F (32 °C) have been measured, but the usual variation is nearly the same as that experienced in February. Bottom-water temperatures of about 43 °F (6 °C) have been recorded near the northern part of the Yucatán Channel. The thickness of the isothermal layer (a surface layer of water of constant temperature) varies from about 3 to more than 500 feet (1 to more than 150 metres), depending on seasonal and local conditions as well as on location. The tidal range is small, averaging less than two feet in most places; in general, only diurnal tides occur—i.e., one period of high water and one of low water during each tidal day (24 hours and 50 minutes).

Climate

The climate of the gulf region varies from tropical to subtropical. Of particular note are the often-devastating hurricanes (tropical cyclones) that strike the region nearly every year. The hurricane season officially runs from June 1 to November 30, during which time meteorologic and oceanographic conditions are conducive for hurricanes to develop anywhere in the gulf. Particularly damaging hurricanes included one in Galveston, Texas, in 1900 and another in and around New Orleans in 2005. Hurricanes spawned in the North Atlantic may also move through the gulf at that time, often picking up strength.

Economic Aspects

Biological resources

The shores of the Gulf of Mexico are a major habitat for waterfowl and shorebirds. Substantial colonies of noddies, boobies, pelicans, and other seabirds winter along the coasts of Mexico and Cuba, as well as on offshore islands. There is a marked absence of marine mammals; the only one of significance, the Caribbean manatee, is diminishing in number.

The gulf waters contain huge populations of fish, particularly along the continental shelf. Commercial fishing is of major economic importance and supplies roughly one-fifth of the total catch in the United States. Shrimps, flounder, red snappers, mullet, oysters, and crabs are the most important commercial species for human consumption. In addition, a large quantity of the fish caught is used to provide fish protein concentrate for animal feeds; menhaden provide the bulk of this catch.

Mineral resources

The shallow continental shelf regions of the Gulf of Mexico contain large deposits of petroleum and natural gas. These deposits have been developed extensively since the 1940s and provide a substantial proportion of domestic needs in the United States. Offshore wells have been drilled primarily in the waters off the coasts of Texas and Louisiana and off Mexico in the Bay of Campeche. Sulfur is also extracted from wells drilled on the continental shelf off Louisiana. Oyster shells are obtained from the shallow waters of the Texas Gulf Coastal Plain and from bays and estuaries. These are used in the chemical industry as a source of calcium carbonate and also provide material for building roads.

Recreation

The coastal waters of the Gulf of Mexico are used extensively for sport fishing, especially for red snappers, flounder, and tarpon. Boating, swimming, and scuba diving also are popular recreations. The Gulf Coast has become a popular tourist destination, especially during winter. Tourism has developed primarily since World War II and has become one of the major components of the regional economy. In addition, the coastal areas, particularly in Florida, have developed into large retirement communities.

The impact of human activity

Shifting demographic patterns in the United States since 1950 have brought millions of new residents to the gulf region. This growing population has increased the demand for fresh water and generated large quantities of sewage and industrial waste (including heavy metals and polychlorinated biphenyls), much of which have been discharged directly into gulf waters or indirectly by rivers draining into the gulf. Offshore drilling has brought oil spills that, on occasion, have fouled beaches and destroyed marine life. More damaging, however, have been modern agricultural practices in much of the United States and Mexico, resulting in runoff contaminated with tremendous amounts of chemical pesticides, herbicides, and fertilizers. Blooms of red algae (Rhodophyta) and regions of oxygen depletion (hypoxia) have increased in frequency, size, and duration; these occurrences have been tied to the introduction into the gulf of large amounts of phosphates and nitrogen, particularly from the outflow of the Mississippi River. Off Louisiana, erosion and changes in relative sea level have caused the submergence of large areas of coastal wetlands; and pollution, siltation, and filling have resulted in the destruction of large areas of the gulf’s mangroves and many of its coral reefs.

Study And Exploration

After Christopher Columbus first made contact with the region in 1492, waves of Spanish explorers entered the gulf and penetrated into the North American interior. By 1600 the major physical features had been discovered, and a system of towns, silver mines, and missions had been established around the gulf shore. Little scientific study of the gulf was carried out until the 20th century, but since then the gulf has come to resemble something of a vast natural laboratory. Major marine research centres are located throughout the region, notably in Texas, Louisiana, and Florida. The gulf has become renowned for the diversity of its marine biota and the dynamics of its numerous barrier beaches; and, because of its vast oil reserves, the stratigraphy of its continental shelf has been studied by geophysicists and seismologists to a greater degree than perhaps that of any other oceanic basin. The frequent occurrence of hurricanes and other tropical storms in the gulf also has made it the focus of much research in climatology.

289389-Intl-countryimg-mexico-542-312.jpg

#4 Re: Ganesh's Puzzles » 10 second questions » Yesterday 17:06:49

Hi,

The solution #6275 is correct. Good work, Monox D. I-Fly!

#6276. Find the value of

.

#5 Re: Ganesh's Puzzles » 10 second questions » Yesterday 14:17:39

Hi,

The solution #6274 is correct. Neat work, Monox D. I-Fly!

#6275. Find the value of

.

#6 Re: Ganesh's Puzzles » 10 second questions » 2017-11-21 20:24:24

Hi,

The solution #6273 is correct. Neat work, zetafunc!

#6274. Find the value of

.

#7 Re: Dark Discussions at Cafe Infinity » crème de la crème » 2017-11-21 15:12:41

236) Manushi Chhillar

From CBSE topper to Miss World 2017, here's Manushi Chhillar's advice to youngsters

Little did we know that Miss World 2017 Manushi Chhillar was a CBSE topper in English.

"When you cease to dream you cease to live," quoted Miss World 2017 and added: "Courage to give flight to your dreams and the ability to believe in yourself  makes life worth living."  The 20-year-old Indian, Manushi Chhillar made the country proud by winning the prestigious title Miss World 2017 on Saturday.

Little did we know that Miss World 2017 was a CBSE topper in English. Chhillar did her schooling from St. Thomas School in New Delhi. According to a report in Tribune, "She was the CBSE topper in English and is associated with Shakti project on menstrual hygiene."

Moreover, she is pursuing Bachelor of Medicine, Bachelor of Surgery (MBBS) from Bhagat Phool Singh Government Medical College for Women in Sonepat.

Family background:

Her father, Dr. Mitra Basu Chhillar, is a scientist at the Defence Research and Development Organisation, while her mother, Dr. Neelam Chhillar, is an associate professor and the department head of neurochemistry at the Institute of Human Behaviour and Allied Sciences.

Advice to youngsters:

According to the official website of Miss World, Manushi Chhillar's advice to youngsters is: "Believe in yourself and never shy away from hard work. It does not matter what others think, 'beauty' is just perception. Get up every morning, tell yourself you are beautiful and gear up to win!"

(Miss World 2017, the 67th edition of the Miss World pageant, was held on 18 November 2017 at the Sanya City Arena in Sanya, China. 118 contestants from all over the world competed for the crown. Stephanie Del Valle of Puerto Rico crowned her successor Manushi Chhillar of India at the end of the event. This is the sixth time that India has won the Miss World, tying it for the most title wins with Venezuela.)

3_1028_1511063508_618x347.jpeg

#8 Re: Ganesh's Puzzles » 10 second questions » 2017-11-20 14:19:52

Hi,

The solution #6272 is correct. Neat work, Monox D. I-Fly!

#6273. Find the value of

.

#9 Re: This is Cool » Numbers ending in "9" » 2017-11-20 08:11:39

Hi kubes,

Nice post to start.

Welcome to the forum!

#10 Re: Dark Discussions at Cafe Infinity » crème de la crème » 2017-11-20 00:39:27

235) Alexander Parkes

Alexander Parkes, (born Dec. 29, 1813, Birmingham, Warwickshire, Eng. - died June 29, 1890, West Dulwich, London), British chemist and inventor noted for his development of various industrial processes and materials.

Much of Parkes’s work was related to metallurgy. He was one of the first to propose introducing small amounts of phosphorus into metal alloys to enhance their strength. One of his most significant inventions was a method of extracting silver from lead ore. This procedure, commonly called the Parkes process (patented in 1850), involves adding zinc to lead and melting the two together. When stirred, the molten zinc reacts and forms compounds with any silver and gold present in the lead. These zinc compounds are lighter than the lead and, on cooling, form a crust that can be readily removed.

Another of Parkes’s important contributions was the discovery of the cold vulcanization process (1841), a method of waterproofing fabrics by means of a solution of rubber and carbon disulfide. Parkes also produced a flexible material called Parkesine (1856) from various mixtures of nitrocellulose, alcohols, camphor, and oils that predated the development of the first plastic, celluloid.

parkes_portrait.jpg

#11 Re: Ganesh's Puzzles » 10 second questions » 2017-11-19 22:43:19

Hi,

The solution #6271 is correct. Excellent, Monox D. I-Fly!

#6272. Find the value of

.

#12 Re: Ganesh's Puzzles » Oral puzzles » 2017-11-19 22:36:22

Hi,

The solution #3836 is correct. Excellent, Monox D. I-Fly!

#3837. If the mode of the data : 64, 60, 48, x, 43, 48, 43, 34, and 43 is 43, find the value of x + 3.

#13 Re: Ganesh's Puzzles » 10 second questions » 2017-11-19 18:12:33

Hi,

#6271. Find the value of x if

.

#14 Re: Ganesh's Puzzles » Oral puzzles » 2017-11-19 18:05:14

Hi,

#3836. Find the median of the first 10 prime numbers.

#15 Re: This is Cool » Miscellany » 2017-11-18 14:43:32

31) Bathyscaphe

Bathyscaphe, navigable diving vessel, developed by the Swiss educator and scientist Auguste Piccard (with assistance in later years from his son Jacques), designed to reach great depths in the ocean.

The first bathyscaphe, the FNRS 2, built in Belgium between 1946 and 1948, was damaged during 1948 trials in the Cape Verde Islands. Substantially rebuilt and greatly improved, the vessel was renamed FNRS 3 and carried out a series of descents under excellent conditions, including one of 4,000 metres (13,000 feet) into the Atlantic off Dakar, Senegal, on February 15, 1954. A second improved bathyscaphe, the Trieste, was launched on August 1, 1953, and dived to 3,150 metres (10,300 feet) in the same year. In 1958 the Trieste was acquired by the United States Navy, taken to California, and equipped with a new cabin designed to enable it to reach the seabed of the great oceanic trenches. Several successive descents were made into the Pacific by Jacques Piccard, and on January 23, 1960, Piccard, accompanied by Lieutenant Don Walsh of the U.S. Navy, dived to a record 10,916 metres (35,814 feet) in the Pacific’s Mariana Trench.

The bathyscaphe consists of two main components: a steel cabin, heavier than water and resistant to sea pressure, to accommodate the observers; and a light container called a float, filled with gasoline, which, being lighter than water, provides the necessary lifting power. The cabin and float are closely linked. On the surface, one or more ballast tanks filled with air provide enough lift to keep the bathyscaphe afloat. When the ballast tank valves are opened, air escapes and is replaced by water, making the whole device heavy enough to start its descent. The gasoline is in direct contact with the sea water and so is compressed at a rate almost exactly in proportion to the prevailing depth. Thus, the bathyscaphe gradually loses buoyancy as it descends, and the speed of its descent tends to increase rapidly. To slow down or to begin the reascent, the pilot releases ballast that consists essentially of iron shot stored in silos and held in place by electromagnets.

bathyscaphe_Trieste.jpg

#16 Re: Dark Discussions at Cafe Infinity » crème de la crème » 2017-11-18 01:41:19

234) Harry Brearley

Harry Brearley (18 February 1871 – 14 July 1948) was an English metallurgist, usually credited with the invention of "rustless steel" (later to be called "stainless steel" in the anglophone world).

Life

Brearley was born on 18 February 1871 in Sheffield, England, the son of John Brearley, a steelworker, and his wife, Jane Brearley née Senior. He left Woodside school at the age of twelve to enter his first employment as a labourer in his father's steelworks, later getting the post of general assistant in the company's chemical laboratory. He married Helen Theresa Crank (1874–1955) on 23 October 1895. For several years, in addition to his laboratory work, he studied at home and later in formal evening classes, to specialize in steel production techniques and associated chemical analysis methods.

By his early thirties, Brearley had earned a reputation as an experienced professional and for being very astute in the resolution of practical, industrial, metallurgical problems. It was in 1908, when two of Sheffield's principal steelmaking companies innovatively agreed to jointly finance a common research laboratory (Brown Firth Laboratories) that Harry Brearley was asked to lead the project.

After leaving Brown Firth, Brearley joined Brown Bayley's Steel Works, also in Sheffield; he became a director of the firm in 1925.

In 1941 Brearley created a charitable trust The Freshgate Trust Foundation, a grantmaking charity operating in Sheffield and South Yorkshire. His aim was to provide a "Fresh Gate" or new opportunity to people like him born into modest circumstances so that they may experience the finer things in life such as travel, education, the arts and music. The foundation is still operating as a registered charity awarding grants for charitable purposes in South Yorkshire.

Brearley died on 14 July 1948, at Torquay, a coastal resort town in Devon, south west England. He was cremated at Efford Crematorium, Efford, near Plymouth on 16 July 1948 and his ashes were scattered in the Efford Crematorium Garden of Remembrance.

In 2013, in the Sheffield University Varsity Brewing Challenge, Sheffield University named their beer – brewed by Thornbridge – Brearleys, to commemorate 100 years since Harry Brearley invented stainless steel.

Stainless steel

In the troubled years immediately before World War I, arms manufacturing increased significantly in the UK, but practical problems were encountered due to erosion (excessive wear) of the internal surfaces of gun barrels. Brearley began to research new steels which could better resist the erosion caused by high temperatures (rather than corrosion, as is often mentioned in this regard). He began to examine the addition of chromium to steel, which was known to raise the material’s melting point, as compared to the standard carbon steels.

The research concentrated on quantifying the effects of varying the levels of carbon (C, at concentrations around 0.2 weight %) and chromium (Cr, in the range of 6 to 15 weight %).

The accidental discovery

In order to undertake metallography to study the microstructure of the experimental alloys (the main factor responsible for a steel's mechanical properties) it was necessary to polish and etch the metallic samples produced. For a carbon steel, a dilute solution of nitric acid in alcohol is sufficient to produce the required etching, but Brearley found that the new chromium steels were very resistant to chemical attack.

Development

It was probably Harry Brearley’s upbringing in Sheffield, a city famous for the manufacture of cutlery since the 16th century, which led him to appreciate the potential of these new steels for applications not only in high-temperature service, as originally envisioned, but also in the mass-production of food-related applications such as cutlery, saucepans and processing equipment etc. Up to that time carbon-steel knives were prone to unhygienic rusting if they were not frequently polished and only expensive sterling silver or EPNS cutlery was generally available to avoid such problems. With this in mind Brearley extended his examinations to include tests with food acids such as vinegar and lemon juice, with very promising results.

Brearley initially called the new alloy "rustless steel"; the more euphonic "stainless steel" was suggested by Ernest Stuart of R.F. Mosley's, a local cutlery manufacturer at Portland Works, and eventually prevailed although Mosley's used the "Rusnorstain" trademark for many years. It is reported that the first true stainless steel, a 0.24wt% C, 12.8wt% Cr ferrous alloy, was produced by Brearley in an electric furnace on 13 August 1913. He was subsequently awarded the Iron and Steel Institute's Bessemer Gold Medal in 1920. The American Society for Metals gives the date for Brearley's creation of casting number 1008 (12.8% chromium, 0.44% manganese, 0.2% silicon, 0.24% carbon and 85.32% iron) as 20 August 1913.

Virtually all research projects into the further development of stainless steels were interrupted by the 1914–18 War, but efforts were renewed in the 1920s. Brearley had left the Brown Firth Laboratories in 1915, following disagreements regarding patent rights, but the research continued under the direction of his successor, Dr. W. H. Hatfield. It is Hatfield who is credited with the development, in 1924, of a stainless steel which even today is probably the widest-used alloy of this type, the so-called "18/8", which in addition to chromium, includes nickel (Ni) in its composition (18wt% Cr, 8wt% Ni).

harrybrearly.jpg

#17 Re: Ganesh's Puzzles » Oral puzzles » 2017-11-17 21:36:59

Hi,

The solution #3834 is correct. Excellent, Monox D. I-Fly!

#3835. If the median of the data : 6, 7, x - 2, x, 17, 20 written in ascending order, is 16. Find the value of x.

#18 Re: Ganesh's Puzzles » Oral puzzles » 2017-11-17 18:56:09

Hi,

The solution #3833 is correct. Neat work, Monox D. I-Fly!

#3834. If the median of the data : 24, 25, 26, x + 2, x + 3, 30, 31, 34 is 27.5, then find the value of x.

#19 Re: Ganesh's Puzzles » 10 second questions » 2017-11-17 15:04:41

Hi,

#6271. If the angles A,B, and C of Δ ABC form an increasing Arithmetic Progression, then find the value of sin B.

#20 Re: Ganesh's Puzzles » Oral puzzles » 2017-11-17 14:57:25

Hi,

#3833. If the Arithmetic Mean of x, x + 3, x + 6, x + 9, and x + 12 is 10, what is the value of x?

#21 Re: Introductions » Hi forum » 2017-11-15 14:29:10

Hi laurenwest144,

It's a pleasure!

#23 Re: Ganesh's Puzzles » 10 second questions » 2017-11-15 08:42:17

Hi,

#6270. The value of acute angle

is such that
, then find the value of
.

#24 Re: Ganesh's Puzzles » Oral puzzles » 2017-11-15 08:27:13

Hi,

#3832. If the mean of first n odd numbers is

, find the value of n.

#25 Re: Dark Discussions at Cafe Infinity » crème de la crème » 2017-11-15 02:39:29

233) Jacques E. Brandenberger

Jacques Edwin Brandenberger (19 October 1872 – 13 July 1954) was a Swiss chemist and textile engineer who in 1908 invented cellophane. He was awarded the Franklin Institute's Elliott Cresson Medal in 1937.

Brandenberger was born in Zurich in 1872. He graduated from the University of Bern in 1895. In 1908 Brandenberger invented cellophane. Made from wood cellulose, cellophane was intended as a coating to make cloth more resistant to staining. After several years of further research and refinements he began production of cellophane in 1920 marketing it for industrial purposes. He sold the US rights to DuPont in 1923.

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