wave technology is a special electricity generating wind technology: winds passing over water create surface waves. The faster the wind speed, the longer the wind is sustained, the greater the distance the wind travels, the greater the wave height, and the greater the wave energy produced. Wave power devices capture energy from ocean surface waves to produce electricity. One type of device is a buoy that rises and falls with a wave. Another type is a surface-following device, whose up-and-down motion increases the pressure on oil to drive a hydraulic motor.
waxes of petroleum origin consist primarily of normal paraffins. Waxes of plant origin consist of esters of unsaturated fatty acids.
weathering is the breakdown of rocks at the Earth’s surface, by the action of rainwater, extremes of temperature, and biological activity. It does not involve the removal of rock material.
The result of weathering is soil formation.
weight of eidence in general is a measure of evidence on one side of an issue as compared with the evidence on the other side of the issue, or to measure the evidence on multiple issues.
In the law: measure of credible proof on one side of a dispute as compared with the credible proof on the other, particularly the probative evidence considered by a judge or jury during a trial.
Medical diagnosis: weights of evidence is a quantitative method for combining evidence in support of a hypothesis. The method was originally developed for a nonspatial application in medical diagnosis, in which the evidence consisted of a set of symptoms and the hypothesis was of the type "this patient has disease x". For each symptom, a pair of weights was calculated, one for presence of the symptom, one for absence of the symptom. The magnitude of the weights depended on the measured association between the symptom and the pattern of disease in a large group of patients. The weights could ten be used to estimate the probability that a new patient would get the disease, based on the presence or absence of symptoms.
Environmental sciences: weights of evidence was adapted in the late 1980s for mineral potential mapping with GIS. In this situation, the evidence consists of a set of exploration datasets (maps), and the hypothesis is "this location is favourable for occurrence of deposit type x". Weights are estimated from the measured association between known mineral occurrences and the values on the maps to be used as predictors. The hypothesis is then repeatedly evaluated for all possible locations on the map using the calculated weights, producing a mineral potential map in which the evidence from several map layers is combined. The method belongs to a group of methods suitable for multi-criteria decision making.
white spirit is a mixture of saturated aliphatic and alicyclic C7 to C12 hydrocarbons with a maximum content of 25% of C7 to C12 alkyl aromatic hydrocarbons.
It is used as an extraction solvent, as a cleaning solvent, as a degreasing solvent and as a solvent in aerosols, paints, wood preservatives, lacquers, varnishes, and asphalt products. It is the most widely used solvent in the paint industry. In households, white spirit is commonly used to clean paint brushes after decorating.
Three different types and three different grades of white spirit exist. The type refers to whether the solvent has been subjected to hydrodesulfurization (removal of sulfur) alone (type 1), solvent extraction (type 2) or hydrogenation (type 3). Each type comprises three different grades: low flash grade, regular grade, and high flash grade. The grade is determined by the crude oil used as the starting material and the conditions of distillation.
Aromatic substance content in white spirit is responsible for most of the adverse effects. It is an irritant, has low acute toxicity by inhalation of the vapour, dermal (touching the skin) and oral routes (ingestion). Exposure to very high concentrations in enclosed spaces can lead to general narcotic effects (drowsiness, dizziness, nausea etc...) and can eventually lead to unconsciousness.
Exposure to an average white spirit concentration of 240 mg/m3 (40 ppm) for more than 13 years could lead to chronic central nervous system effects.
It is moderately toxic to aquatic organisms, is unlikely to present significant hazards to the environment. It should not however, be purposely poured down the sink or freshwater drain if avoidable. It should be disposed of correctly wherever possible.
The physical properties of the three types (low, medium and high flash-point) of white spirit are summarized in the table.
|Initial boiling point (IBP) (°C)||130-144||145-174||175-200|
|Final boiling point (°C)||IBP+21, max. 220|
|Average relative molecular mass||140||150||160|
|Relative density (15 °C)||0.765||0.780||0.795|
|Flash point (°C)||21-30||31-54||> 55|
|Vapour pressure (kPa, 20 °C)||1.4||0.6||0.1|
|Volatility (n-butyl acetate=1)||0.47||0.15||0.04|
|Autoignition temperature (°C)||240||240||230|
|Explosion limits (Flammable Range) (% by volume in air)||0.6 - 6.5||0.6 - 6.5||0.6 - 8|
|Vapour density (air=1)||4.5-5||4.5-5||4.5-5|
|Refractive index (at 20 °C)||1.41-1.44||1.41-1.44||1.41-1.44|
|Viscosity (cps, 25 °C)||0.74-1.65||0.74-1.65||0.74-1.65|
|Solubility (% by weight in water)||< 0.1||< 0.1||< 0.1|
|Aniline point (°C)||60-75||60-75||60-75|
|Reactivity||reaction with strong oxidizing agents|
|Odor threshold (mg/m3)||-||0.5-5||4|
electricity-generating wind technologies belong to the WWS (Wind, Water and Sun) group of the renewable energy sources.
Wind turbines convert the energy of the wind into electricity. Generally, a gearbox turns the slow-moving turbine rotor into faster-rotating gears, which convert mechanical energy to electricity in a generator. Some modern turbines are gearless. Although less efficient, small turbines can be used in homes or buildings. Wind farms today appear on land and offshore, with individual turbines ranging in size up to 7 MW.
Wireless Local Area Network
physical surroundings and social environment at a workplace.
Mechanical hazards include:
By type of agent:
- Impact force: collisions, falls from height
- Struck by objects
- Confined space
- Slips and trips
- Falling on a pointed object
- Compressed air/high pressure fluids (such as cutting fluid)
- Equipment-related injury
By type of damage:
- Friction and abrasion
- Stabbing and puncture
Other physical hazards:
- Barotrauma (hypobaric/hyperbaric pressure)
- Ionizing radiation
- Cold stress (hypothermia)
- Heat stress (hyperthermia)
- Dehydration (due to sweating)
Biological hazards include:
- Blood-borne pathogens
Chemical hazards include:
- Heavy metals
- Asbestos and other fine dust/fibrous materials
- Fumes (noxious gases/vapors)
- Highly-reactive chemicals
- Fire, conflagration and explosion hazards:
Psychosocial issues include:
- Work-related stress, whose causal factors include excessive working time and overwork
- Violence from outside the organisation
- Bullying, which may include emotional and verbal abuse
- Sexual harassment
- Exposure to unhealthy elements during meetings with business associates, e.g. tobacco, uncontrolled alcohol
Musculoskeletal disorders, avoided by the employment of good ergonomic design
the World Reference Base for soil resources is a two-level system of soil classification with 30 Soil Reference Groups and a series of uniquely defined qualifiers for specific soil characteristics.
For describing and defining soils the WRB exploits the following nomenclature:
- soil characteristics comprise single observable or measured parameters;
- soil properties are a combination of characteristics indicating soil-forming processes;
- soil horizons represent three-dimensional bodies containing one or more soil properties
Waste Water Treatment Plant
World Wide Web
World Wide Web, web, internet
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