Laundry detergent, or washing powder, is a type of detergent (cleaning agent) that is added for cleaning laundry. In common usage, "detergent" refers to mixtures of chemical compounds including alkylbenzenesulfonates, which are similar to soap but are less affected by hard water. In most household contexts, the term detergent refers to laundry detergent vs hand soap or other types of cleaning agents. Most detergent is delivered in powdered form.
From ancient times, chemical additives were recognized for their ability to facilitate the mechanical washing with water. The Italians used a mix of sulfur and water with charcoal to clean cloth. Egyptians added ashes and silicates to soften water. Soaps were the first detergents. The detergent effects of certain synthetic surfactants were noted in Germany in 1917, in response to shortages of soap during World War I. In the 1930s, commercially viable routes to fatty alcohols were developed, and these new materials were converted to their sulfate esters, key ingredients in the commercially important German brand FEWA, produced by BASF, and Dreft, the US brand produced by Procter and Gamble. Such detergents were mainly used in industry until after World War II. By then, new developments and the later conversion of aviation fuel plants to produce tetrapropylene, used in household detergents, caused a fast growth of domestic use in the late 1940s.
Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, that is, in the range between 400 nm and 10 nm, corresponding to photon energies from 3 eV to 124 eV. It is so-named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the color violet. These frequencies are invisible to humans, but near UV is visible to a number of insects and birds.
UV light is found in sunlight and is emitted by electric arcs and specialized lights such as mercury lamps and black lights. It can cause chemical reactions, and causes many substances to glow or fluoresce. A large fraction of UV, including all that reaches the surface of the Earth, is classified as non-ionizing radiation. The higher energies of the ultraviolet spectrum from wavelengths about 120 nm to 10 nm ('extreme' ultraviolet) are ionizing, but due to this effect, these wavelengths are absorbed by nitrogen and even more strongly by dioxygen, and thus have an extremely short path length through air. However, the entire spectrum of ultraviolet radiation has some of the biological features of ionizing radiation: it does far more damage to many molecules in biological systems than is accounted for by simple heating effects (an example is sunburn). These properties derive from the ultraviolet photon's power to alter chemical bonds in molecules, even without having enough energy to ionize atoms.
Electromagnetic radiation (EM radiation or EMR) is one of the fundamental phenomena of electromagnetism, behaving as waves propagating through space, and also as photon particles traveling through space, carrying radiant energy. In a vacuum, it propagates at a characteristic speed, the speed of light, normally in straight lines. EMR is emitted and absorbed by charged particles. As an electromagnetic wave, it has both electric and magnetic field components, which oscillate in a fixed relationship to one another, perpendicular to each other and perpendicular to the direction of energy and wave propagation.
EMR is characterized by the frequency or wavelength of its wave. The electromagnetic spectrum, in order of increasing frequency and decreasing wavelength, consists of radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. The eyes of various organisms sense a somewhat variable but relatively small range of frequencies of EMR called the visible spectrum or light. Higher frequencies correspond to proportionately more energy carried by each photon; for instance, a single gamma ray photon carries far more energy than a single photon of visible light.
Home appliances are electrical/mechanical machines which accomplish some household functions, such as cooking or cleaning. Home appliances can be classified into:
This division is also noticeable in the maintenance and repair of these kinds of products. Brown goods usually require high technical knowledge and skills (which get more complex with time, such as going from a soldering iron to a hot-air soldering station), while white goods may need more practical skills and "brute force" to manipulate the devices and heavy tools required to repair them.
A black light, also referred to as a UV-A light, Wood's lamp, or simply ultraviolet light, is a lamp which emits long wave (UV-A) ultraviolet light and not much visible light. The lamp has a dark purple filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim purple glow when operating. Black light bulbs which have this filter have a lighting industry designation that includes the letters "BLB".
A second type of bulb which is also called a black light produces ultraviolet but does not have the filter material, so it produces more visible light and has a blue color when operating. These are made for use in "bug zapper" insect traps and are identified by the industry designation "BL".
A biological detergent is a laundry detergent that contains enzymes harvested from micro-organisms such as bacteria adapted to live in hot springs. The description is commonly used in the United Kingdom, where other washing detergents are described as "non-biological" (or bio and "non-bio"). Most manufacturers of biological detergents also produce non-biological ones.
Biological detergents clean in the same way as non-biological ones with additional effects from the enzymes, whose purpose is to break down protein, starches and fat in dirt and stains on clothing to be laundered, for example food stains, sweat and mud. Tests by the Consumers' Association in the UK published in their Which? magazine rated the cleaning performance of washing powders based on stain removal, whiteness, and colour fading. It was found that the performance of various makes of biological powders ranged from 58% to 81%, and non-biological powders scored from 41% to 70%. The enzymes in biological detergents enable effective cleaning at lower temperatures than required by normal detergents, but are denatured at higher temperatures—about 50 °C is recommended. A biological detergent can contain α-amylase, a cellulase, a protease and a lipase.