a tablet PC (personal computer) is a tablet-sized computer that also has the key features of a full-size personal computer. A tablet PC is essentially a small laptop computer, equipped with a rotatable touchscreen as an additional input device, and running a standard (or lightly adapted) PC operating system like Windows or Linux.
target organ effects indicate which bodily organs are most likely to be affected by exposure to a chemical substance.The classes of target organ effects are summarized in the table below.
The following is a target organ categorization of effects which may occur, including examples of signs and symptoms and chemicals which have been found to cause such effects. These examples are presented to illustrate the range and diversity of effects and hazards found in the workplace, and the broad scope employers must consider in this area, but are not intended to be all-inclusive.
In the table we give the type of chemical substance and its organ-specific effect, the signs and symptoms, and some chemical substances as examples.
|Hepatotoxins - produce hepatic (liver) damage||jaundice, liver enlargement||Carbon tetrachloride, nitrosamines|
|Nephrotoxins - produce kidney damage||edema, proteinuria||Halogenated hydrocarbons, uranium|
|Neurotoxins - produce their primary toxic effects on the nervous system||narcosis, behavioral changes, decrease in motor functions||Mercury, carbon disulfide|
|Hemato-poietic agents - act on the blood or hemato-poietic system, decrease hemoglobin function, deprive the body tissues of oxygen||cyanosis, loss of consciousness||Carbon monoxide, cyanides|
|Agents which damage the lung - these irritate or damage pulmonary (lung) tissue||cough, tightness in chest, shortness of breath||Silica, asbestos|
|Reproductive toxins - affect the reproductive capabilities including chromosomal damage (mutations) and effects on fetuses (teratogenesis)||birth defects, sterility||Lead, DBCP|
|Cutaneous hazards - affect the dermal layer (skin) of the body||defatting of the skin, rashes, irritation||Ketones, chlorinated compounds|
|Eye hazards - affect the eye or visual capacity||conjunctivitis, corneal damage||organic solvents, acids|
When working with chemical substances that have target organ effects it is critical to prevent exposure. This is especially true if you have a pre-existing condition, disease or injury to that particular organ.
While this environmnetal lexikon refers specifically to organs that can be damaged by a substance, the medical community also refers to organs targeted by diseases or other conditions. For example, the medical literature discusses target organ damage to the brain, heart and kidneys in the context of hypertension (high blood pressure). These target organ effects can manifest themselves even before hypertension is diagnosed or progresses from the pre-hypertensive state. Other diseases/conditions target other organs, of course.
target quality in environmental management is the desired quality of the environment not posing unacceptable risk on the ecosystem and humans.
Unacceptable risk of chemical substances can be characterised by the risk characterisation ratio, which is the ratio of the predicted environmental concentration PEC and the predicted no effect concentration PNEC of a hazardous chemical RCR=PEC/PNEC. The targeted environmental concentration is smaller than or equal to the "no effect" concentration.
environmental target concentrations or levels are associated with a "no risk" situation in the environment.
Environmental target values are risk based target values or risk based quality criteria in the modern environmental management and legislation. It means that environmental target values are calculted from the risk characterisation ratio in condition of RCR < or =1, which represents an acceptable risk.
In addition, the term technical dossier is also used to refer to one of the two parts of the Annex XV dossier. It supports the Annex XV report.(Source: REACH Glossary)
Earth's atmosphere can be divided into five main layers. These layers are mainly determined by whether temperature increases or decreases with altitude. From highest to lowest, these layers are:
The troposphere begins at the Earth surface and extends to between 7 km (23,000 ft) at the poles and 17 km (56,000 ft) at the equator, with some variation due to weather. The troposphere is mostly heated by transfer of energy from the surface, so on average the lowest part of the troposphere is warmest and temperature decreases with altitude. This promotes vertical mixing. The troposphere contains roughly 80% of the mass of the atmosphere. The tropopause is the boundary between the troposphere and stratosphere. The temperature decrease is 6,5 oC/km upwards.
The stratosphere extends from the tropopause to about 51 km (32 mi; 170,000 ft). Temperature increases with height, which restricts turbulence and mixing. The stratopause, which is the boundary between the stratosphere and mesosphere, typically is at 50 to 55 km (31 to 34 mi; 160,000 to 180,000 ft). The pressure here is 1/1000th sea level and the temperature between −50 and −90 oC. The ozone-layer in the stratosphere may reach 0 oC due to the absorption of Sun UV radiation.
The mesosphere extends from the stratopause to 80–85 km (50–53 mi; 260,000–280,000 ft). It is the layer where most meteors burn up upon entering the atmosphere. Temperature decreases with height in the mesosphere. The mesopause, the temperature minimum that marks the top of the mesosphere, is the coldest place on Earth and has an average temperature around −85 °C (−121.0 °F; 188.1 K). Due to the cold temperature of the mesophere, water vapor is frozen, forming ice clouds (or Noctilucent clouds). A type of lightning referred to as either sprites or ELVES, form many miles above thunderclouds in the trophosphere.
Temperature increases with height in the thermosphere from the mesopause up to the thermopause, then is constant with height. The temperature of this layer can rise to 1,500 °C (2,730 °F), though the gas molecules are so far apart that temperature in the usual sense is not well defined. The International Space Station orbits in this layer, between 320 and 380 km (200 and 240 mi). The top of the thermosphere is the bottom of the exosphere, called the exobase. Its height varies with solar activity and ranges from about 350–800 km (220–500 mi; 1,100,000–2,600,000 ft).
Exosphere is the outermost layer of Earth's atmosphere extends from the exobase upward. Here the particles are so far apart that they can travel hundreds of kilometres without colliding with one another. Since the particles rarely collide, the atmosphere no longer behaves like a fluid. These free-moving particles follow ballistic trajectories and may migrate into and out of the magnetosphere or the solar wind. The exosphere is mainly composed of hydrogen and helium.
conversion between Celsius and Fahrenheit:
|degrees Celsius||degrees Fahrenheit||multiply by 1.8 and add 32|
|degrees Fahrenheit||degrees Celsius||subtract 32 and divide by 1.8|
see teratogenic effect
terrestrial carbon sequestration is the process through which carbon dioxide (CO2) from the atmosphere is absorbed by trees, plants and crops through photosynthesis, and stored as carbon in biomass (tree trunks, branches, foliage and roots) and soils. The term "sinks" is also used to refer to forests, croplands, and grazing lands, and their ability to sequester carbon. Agriculture and forestry activities can also release CO2 to the atmosphere. Therefore, a carbon sink occurs when carbon sequestration is greater than carbon releases over some time period.
terrestrial toxicology concentrates on the terrestrial ecosystem. It measures the effect of hazardous chemical substances and physical agents on the memebers of the ecosystem and on the whole ecosystem structure.
soil texture is a soil property used to describe the relative proportion of different grain sizes of mineral particles in a soil. Particles are grouped according to their size into what are called soil separates. These separates are typically named clay, silt, and sand. Soil texture classification is based on the fractions of soil separates present in a soil. The soil texture triangle is a diagram often used to figure out soil textures.
|Name of soil separate||Diameter limits (mm) |
|Clay||less than 0.002|
|Very fine sand||0.05–0.10|
|Very coarse sand||1.00–2.00|
thermally enhanced recovery is an in situ treatment process that uses heat to increase the volatilization rate of organics and facilitate extraction. Volatilized contaminants are typically removed from the vadose zone using soil vapor extraction. Specific types of thermally enhanced recovery techniques include radio frequency heating, conductive heating, steam heating, in situ steam stripping, hot air injection, dynamic underground stripping, in situ thermal desorption, and electrical resistive heating. Thermally enhanced recovery is usually applied to contaminated soil but may also be applied to groundwater.
thermolysis or thermal decomposition is defined as a chemical reaction in which a chemical substance brackes up into at least two chemical substances when heated. The reaction is usuallyendothermic, as heat is required to break the chemical bounds during decomposition.