34 résultats pour "diamond"
-
Harry Bertoia the diamond chair
The Diamond Chair C rée r en 1952 par Harry BERTOIA avec Hans Florence Knoll. Attention à l'orthographe et à la qualité des photos Il faut présenter cette chaise quand , où , décrivez la donner plusieurs point de vue 4 illustrations pour un diaporama, c'est beaucoup beaucoup trop peu
- Diamond Sutra
-
Gemstones.
In the late 1960s a method was developed for “growing” diamonds by heating a diamond particle to a high temperature and subjecting it to methane gas. The gasdecomposes into carbon atoms, which adhere to the diamond crystal. The crystal structure of the enlarged diamond is identical to that of a natural diamond. Diamondsof about 1 carat (200 mg or 0.007 oz) have been produced by this method, but their cost is still considerably higher than that of naturally occurring diamonds. Sapphires are made...
-
Botswana - country.
at birth was 50.2 years, also a significant improvement. The urban population of Botswana has increased rapidly, from 18 percent of the total in 1981 to 51 percent in 2003. Gaborone, the capital, is the largest city and mainbusiness center. Other business centers are Francistown, Selebi-Pikwe, Molepolole, Kanye, and Serowe. Botswana received its name from the country’s principal ethnic group, the Tswana. Other ethnic groups include the Kgalagadi, Kalanga, and Basarwa. There are also asmall numbe...
-
Carbon - chemistry.
Graphite is black and slippery and conducts electricity. In graphite, the atoms form planar, or flat, layers. Each layer is made up of rings containing six carbon atoms.The rings are linked to each other in a structure that resembles the hexagonal mesh of chicken wire. Each atom has three sigma bonds (with 120° between any two ofthe bonds) and belongs to three neighboring rings. The fourth electron of each atom becomes part of an extensive pi bond system. Graphite conducts electricity,because th...
-
Bicycle.
narrow as possible to minimize weight and interference with pedaling. F Specialty Bicycles Many other types of bicycles are designed for special purposes. Although not as common as standard single-rider racing, touring, mountain, or recreational bicycles,they nonetheless have significant niches. Recumbent bicycles are bicycles on which the rider sits upright as if in a chair, with legs and feet stretched out in front. Because they support the rider’s lower back,recumbents allow the rider far mo...
-
Sierra Leone (country) - country.
commodities such as palm oil, palm kernels, coffee, cacao, ginger, kola nuts, and piassava (palm fibers) are grown for export. Cattle, goats, and sheep are raised, andthe fishing industry is of increasing importance. B Mining Gem and industrial diamonds are the leading mineral products of Sierra Leone. In 2004, 309,390 carats of gem-quality diamonds were produced. Rutile, a titanium oreof which Sierra Leone has one of the world’s largest deposits, and bauxite are also mined in large quantities....
-
South Africa - country.
The major soil zones are conditioned largely by climatic factors. In the semiarid north and west, soils are alkaline and poorly developed. In the southern part of WesternCape Province, rain falls mostly in the winter months, and soils there form slowly and are generally thin and immature. The moderate temperatures and summer rainfallof the High Veld and eastern coastal areas create conditions for more productive organic decomposition, leading to dark, fertile soils, or chernozems, similar to tho...
-
-
Honolulu - geography.
Much of Honolulu’s growth and development has concentrated along the southern coast of Oahu. This area is framed to the east by the remnants of a large extinct volcanoknown as Diamond Head and includes Waikiki, located west of Diamond Head; the downtown area, situated near Honolulu Harbor; Honolulu International Airport; andnewer communities in the western part of the island. Two parallel mountain ranges of volcanic origin, the Koolau and Waianae mountains, run north to south across much ofthe i...
-
Tanzania - country.
The population of Tanzania (2008 estimate) is 40,213,162, giving the country an overall population density of 45 persons per sq km (118 per sq mi). Yet the populationdistribution is irregular, with high densities found near fertile soils around Kilimanjaro and the shores of Lake Malawi, and comparatively low density throughout much ofthe interior of the country. In the late 1960s and 1970s the Tanzanian government resettled most of the rural population in collective farming villages as part of i...
-
Yellowknife (Northwest Territories) - Geography.
VII HISTORY Indigenous nations have lived around Yellowknife Bay for thousands of years. The historic occupants were the Athapaskan-speaking Dogrib people, hunters of caribou.The Dogrib were displaced briefly in the early 19th century by the Yellowknife band of the Chipewyan nation, who moved into the area to participate in the fur trade.The bay, and eventually the city, were named for the Yellowknife band, whose name is believed to derive from their yellow knife blades hammered out of native...
-
Angola (country) - country.
Portugal in 1975, it had approximately 400,000 Portuguese settlers. The vast majority of the Portuguese community has since departed for Portugal. A Population Characteristics The 2008 estimated population of Angola, including Cabinda, was 12,531,357. The population distribution, however, was uneven, with about 70 percent of thepopulation concentrated in the north and along the coast. The rate of population increase was 2.1 percent annually in 2008. The population is overwhelmingly rural; only3...
-
Democratic Republic of the Congo - country.
Except in the high elevations, the country’s climate is very hot and humid. The average annual temperature in the low central area is about 27°C (about 80°F).Temperatures are considerably higher in February, the hottest month. At altitudes above about 1,500 m (about 5,000 ft) the average annual temperature is about 19°C(about 66°F). Average annual rainfall is about 1,500 mm (about 60 in) in the north and about 1,300 mm (about 50 in) in the south. Frequent heavy rains occur fromApril to November...
-
Australia - country.
itself forms most of the border between New South Wales and Victoria. Considerable lengths of the Murray, Darling, and Murrumbidgee rivers are navigable during thewet seasons. The central plains region, also known as the Channel Country, is interlaced by a network of rivers. During the rainy season these rivers flood the low-lying countryside,but in dry months they become merely a series of water holes. The Victoria, Daly, and Roper rivers drain a section of the Northern Territory. In Queensland...
-
Australia - Geography.
itself forms most of the border between New South Wales and Victoria. Considerable lengths of the Murray, Darling, and Murrumbidgee rivers are navigable during thewet seasons. The central plains region, also known as the Channel Country, is interlaced by a network of rivers. During the rainy season these rivers flood the low-lying countryside,but in dry months they become merely a series of water holes. The Victoria, Daly, and Roper rivers drain a section of the Northern Territory. In Queensland...
-
Central African Republic - country.
Manufacturing activity in the Central African Republic is very limited. Products include cottonseed, peanut, and sesame oils; textiles; leather goods; tobacco products;soap; flour; bricks; and paint. The output of electricity in 2003 was 106 million kilowatt-hours, 80.19 percent of which was generated in hydroelectric installations. Gemdiamonds account for nearly all the country’s mineral output and two-thirds of its export revenue. Production was 250,000 carats in 2004. Uranium was discovered i...
-
-
Smithsonian Institution.
F Arthur M. Sackler Gallery The Arthur M. Sackler Gallery houses a permanent collection of art from China, South and Southeast Asia, ancient and Islamic Iran, and Japan. Changing exhibitions ofAsian art are drawn from collections in the United States and abroad. The core of the collection was a gift from American research physician and medical publisherArthur M. Sackler. G Cooper-Hewitt, National Design Museum The Cooper-Hewitt is located in New York City and features examples of historical an...
-
Nanotechnology.
ever-finer method of reducing material to the nanoscale size. Instead, nanostructures would be assembled atom by atom and molecule by molecule, from the atomiclevel up, just as occurs in nature. However, assembly at this scale has its own challenges. In school, children learn about some of these challenges when they study the random Brownian motion seen in particles suspended in liquids such as water. Theparticles themselves are not moving. Rather, the water molecules that surround the particles...
-
Arctic - Geography.
The Arctic is not a frozen desert devoid of life on land or sea, even during the cold, dark winter months. Spring brings a phenomenal resurgence of plant and animal life.Low temperatures are not always the critical element—moisture, the type of soil, and available solar energy are also extremely important. Some animals adapt well toArctic conditions; for instance, a number of species of mammals and birds carry additional insulation, such as fat, in cold months. Arctic summers with extended dayli...
-
Optics
I
INTRODUCTION
Mirage
Mirages appear because differences in air temperature cause light rays from an object to take different paths to a viewer's
eye.
Refraction of Light by DiamondsThe brilliance of diamonds is due to their high refractive index, a measure of how strongly a transparent material bendslight rays. The skill of the gem-cutter lies in angling the facets of the stone so that each light ray entering it is reflectedmany times before it emerges again.Spencer Grant/Photo Researchers, Inc. The amount of light reflected depends on the ratio of the refractive indexes for the two media. The plane of incidence contains the incident ray and...
-
Hawaii (state) - geography.
limestone along the coast. The volcanoes of the Hawaiian Islands are all so-called shield volcanoes, or lava domes. Unlike the volcanoes of Alaska and South America, those of Hawaii were notcreated by very explosive eruptions. Formed mostly by lava flows, they are great rounded mountain masses, rather than steep-sided cones. Mauna Kea, dormant forcenturies, is the highest mountain in the state. It rises to 4,205 m (13,796 ft) above sea level, and its summit is dotted with cinder cones formed by...
-
Hawaii (state) - USA History.
limestone along the coast. The volcanoes of the Hawaiian Islands are all so-called shield volcanoes, or lava domes. Unlike the volcanoes of Alaska and South America, those of Hawaii were notcreated by very explosive eruptions. Formed mostly by lava flows, they are great rounded mountain masses, rather than steep-sided cones. Mauna Kea, dormant forcenturies, is the highest mountain in the state. It rises to 4,205 m (13,796 ft) above sea level, and its summit is dotted with cinder cones formed by...
-
Diamond guitar
Tico donna l'alerte et les deux ont courru à la rivière. Mais malheureusement seul Tico pu s'enfuir car Mr.Schaeffer se blessa à la cheville. Sa vie en prison repris son court mais il a été félicité car le Capitaine avait dit à tout le monde qu'il avait tenté de ratraper Tico, pour l'empecher de fuir. Dans cette histoire on peut voir que l'amitié est quelque chose de très important. Nous avons ici deux amitiés. Celle de Mr. Schaeffer et Tico. Et celle de Mr. Schaeffer et le Capitain. L'amitié...
-
Northwest Territories - Geography.
million years ago by the severe bending (folding) and faulting (breaking) of sedimentary rock that was once part of the Interior Plains. During the Wisconsin Ice Age,alpine glaciers covered the Cordillera, and the movement of the glaciers created razor-sharp peaks and ridges in these mountains. The moving glaciers also createdbroad U-shaped valleys. To the east of the Interior Plains, the ancient rocks of the Canadian Shield are exposed at the Earth’s surface, resulting in a rough, rolling terra...
-
-
Northwest Territories - Canadian History.
million years ago by the severe bending (folding) and faulting (breaking) of sedimentary rock that was once part of the Interior Plains. During the Wisconsin Ice Age,alpine glaciers covered the Cordillera, and the movement of the glaciers created razor-sharp peaks and ridges in these mountains. The moving glaciers also createdbroad U-shaped valleys. To the east of the Interior Plains, the ancient rocks of the Canadian Shield are exposed at the Earth’s surface, resulting in a rough, rolling terra...
-
Frank Lloyd Wright.
C Usonian Houses Wright achieved his goal of low-cost, democratic American architecture with his Usonian houses of the 1930s. Usonia was Wright’s term for the United States of North America, with an i added for a pleasing sound. The Usonian house had a simple design, usually with an L-shaped floor plan. This plan separated the noisier living space on one leg of the L from the quieter bedroom space on the other leg. The floor was made of concrete slabs, typically in a square grid of 4 by 4...
-
Guinea - country.
Mining operations in 2004 yielded 16 million metric tons of bauxite, 468,400 carats of high-quality diamonds, and 16,000 kg (35,300 lb) of gold. Environmental concernsand political instability in neighboring Liberia have delayed exploitation of high-grade iron ore from Mount Nimba. In 1999 the national budget included $466 million in revenues and $414 million in expenditures. The unit of currency is the Guinean franc, which is divided into 100 centimes (3,644 francs equal U.S.$1; 2005 average...
-
Frank Lloyd Wright
I
INTRODUCTION
Robie House
The Frederick C.
Hills/DeCaro HouseAmerican architect Frank Lloyd Wright, a pioneer of modern architecture, lived and worked in the Chicago area during thelate 19th and early 20th centuries. He designed many single-family houses, known as prairie houses. The Hills/DeCarohouse in Oak Park, west of Chicago, is one of more than 20 houses Wright designed while living in the town between 1890and 1910.© 2007 Frank Lloyd Wright Foundation / Artists Rights Society (ARS), New York / Photo: Mary Ann Hemphill/Photo Researc...
-
Côte d'Ivoire - country.
D Culture Traditional artistic expressions in Côte d’Ivoire include woodcarvings (particularly masks), decorative fabrics, and acrobatic dancing. Urban populations have beengreatly influenced by French culture. The French language is almost universally used in the written literature of Côte d’Ivoire, to the exclusion of the African languages. IV ECONOMY About 60 percent of Côte d’Ivoire’s total labor force is employed in farming and forestry. Government efforts to avoid dependence on a small...
-
Liberia - country.
West Atlantic, or Kwa linguistic groups. D Education Education is free and compulsory for children between the ages of 6 and 15. However, a scarcity of educational facilities means that few Liberians progress beyondprimary school. Almost all children of primary school-age attend school, but the figure drops to 23 percent (1999–2000) for secondary school-age children. Just 60percent of the population was literate in 2005. Higher education is provided by the University of Liberia (1862), in Monro...
-
Guyana - country.
European patterns of living. People of mixed African and European ancestry form a distinct group in Guyana, maintaining closer social ties to the European communitythan to the African Guyanese community. Asians from the Indian subcontinent began to arrive in the 19th century, following the abolition of slavery in Guyana, to work as indentured and contract laborers. Theycontinued to arrive until 1917, when Britain outlawed indentured servitude. Thousands of Indians chose to remain in Guyana after...
-
Skiing.
Safety is very important to all skiers, and all Alpine resorts have a ski patrol. The ski patrol’s responsibility is to take care of injured skiers, to mark hazardous spots ontrails, to make sure that trails are in good condition before opening them, and, at times, to act as traffic police in congested areas. Skiers are also responsible for takingtheir own safety into consideration, as well as that of others. Anyone who participates in the sport should be aware of the Skier’s Responsibility Code...
-
-
Native American Art.
folding, braiding or weaving, could also be sewn onto the hide. The production of decorated clothing and bags increased after contact with Europeans as a greater variety of textiles and other materials became available throughtrade. Imported glass beads inspired native women, who quickly adapted quillwork techniques for the creation of beaded apparel. European curvilinear and floraldesigns of the 19th century proved as meaningful for the native women who worked with them as they were for the non...
-
Venezuela - country.
Venezuela has six navigable rivers. Of the thousand or more streams in the country, the majority flow into the Orinoco. The Orinoco flows east across central Venezuelaand drains approximately four-fifths of the total area of the country. With the tributaries—the Apure, Meta, and Negro rivers—it forms the outlet into the Atlantic Oceanfor the waters of much of the interior of Colombia, as well as of inland Venezuela. F Climate The climate of Venezuela is tropical on the Llanos and along the coas...