Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have often been used to describe opposites such as good and evil, the Dark Ages versus the Age of Enlightenment, and night versus day. Since the Middle Ages, black has been the symbolic color of solemnity and authority, and for this reason it is still commonly worn by judges and magistrates.
Black was one of the first colors used by artists in Neolithic cave paintings. It was used in ancient Egypt and Greece as the color of the underworld. In the Roman Empire, it became the color of mourning, and over the centuries it was frequently associated with death, evil, witches, and magic. In the 14th century, it was worn by royalty, clergy, judges, and government officials in much of Europe. It became the color worn by English romantic poets, businessmen and statesmen in the 19th century, and a high fashion color in the 20th century. According to surveys in Europe and North America, it is the color most commonly associated with mourning, the end, secrets, magic, force, violence, fear, evil, and elegance.
Black is the most common ink color used for printing books, newspapers and documents, as it provides the highest contrast with white paper and thus is the easiest color to read. Similarly, black text on a white screen is the most common format used on computer screens. As of September 2019, the darkest material is made by MIT engineers from vertically aligned carbon nanotubes.
Cooking, also known as cookery or professionally as the culinary arts, is the art, science and craft of using heat to make food more palatable, digestible, nutritious, or safe. Cooking techniques and ingredients vary widely, from grilling food over an open fire, to using electric stoves, to baking in various types of ovens, to boiling and blanching in water, reflecting local conditions, techniques and traditions. Cooking is an aspect of all human societies and a cultural universal.
Types of cooking also depend on the skill levels and training of the cooks. Cooking is done both by people in their own dwellings and by professional cooks and chefs in restaurants and other food establishments.
Preparing food with heat or fire is an activity unique to humans. Archeological evidence of cooking fires from at least 300,000 years ago exists, but some estimate that humans started cooking up to 2 million years ago.
The expansion of agriculture, commerce, trade, and transportation between civilizations in different regions offered cooks many new ingredients. New inventions and technologies, such as the invention of pottery for holding and boiling of water, expanded cooking techniques. Some modern cooks apply advanced scientific techniques to food preparation to further enhance the flavor of the dish served.
A gadget is a mechanical device or any ingenious article. Gadgets are sometimes referred to as gizmos.
A kitchen is a room or part of a room used for cooking and food preparation in a dwelling or in a commercial establishment. A modern middle-class residential kitchen is typically equipped with a stove, a sink with hot and cold running water, a refrigerator, and worktops and kitchen cabinets arranged according to a modular design. Many households have a microwave oven, a dishwasher, and other electric appliances. The main functions of a kitchen are to store, prepare and cook food (and to complete related tasks such as dishwashing). The room or area may also be used for dining (or small meals such as breakfast), entertaining and laundry. The design and construction of kitchens is a huge market all over the world.
Commercial kitchens are found in restaurants, cafeterias, hotels, hospitals, educational and workplace facilities, army barracks, and similar establishments. These kitchens are generally larger and equipped with bigger and more heavy-duty equipment than a residential kitchen. For example, a large restaurant may have a huge walk-in refrigerator and a large commercial dishwasher machine. In some instances, commercial kitchen equipment such as commercial sinks is used in household settings as it offers ease of use for food preparation and high durability.
In developed countries, commercial kitchens are generally subject to public health laws. They are inspected periodically by public-health officials, and forced to close if they do not meet hygienic requirements mandated by law.
The lux (symbol: lx) is the unit of illuminance, or luminous flux per unit area, in the International System of Units (SI). It is equal to one lumen per square metre. In photometry, this is used as a measure of the irradiance, as perceived by the spectrally unequally responding human eye, of light that hits or passes through a surface. It is analogous to the radiometric unit watt per square metre, but with the power at each wavelength weighted according to the luminosity function, a model of human visual brightness perception, standardized by the CIE and ISO. In English, "lux" is used as both the singular and plural form.
The word is derived from the Latin word for "light", lux.
Nylon is a family of synthetic polymers characterised by amide linkages, typically connecting aliphatic or semi-aromatic groups.
Nylons are generally white or colourless and possess a soft texture, with some varieties exhibiting a silk-like appearance. As thermoplastics, nylons can be melt-processed into fibres, films, and diverse shapes.: 2 The properties of nylons are often modified by blending with a variety of additives.
Numerous types of nylon are available. One family, designated nylon-XY, is derived from diamines and dicarboxylic acids of carbon chain lengths X and Y, respectively. An important example is nylon-6,6 ((−C(O)(CH2)4C(O)−NH(CH2)6NH−)n). Another family, designated nylon-Z, is derived from aminocarboxylic acids with carbon chain length Z. An example is nylon-[6].
Nylon polymers have extensive commercial applications, including uses in textiles and fibres (such as apparel, flooring and rubber reinforcement), molded components for automotive and electrical equipment, and films (mostly for food packaging).
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