Lexikon
soil value marks are used in a Hungarian system for the characterisation of agricultural soil quality by a decimal mark system. 0−9 marks for the characteristics, and further 0−9 marks for the quality within each characteristics. The highest value is 100 and the productivity of the soil which is characterised by the marks is equivalent with the % of the maximum.
soil vapor extraction SVE is used to remediate unsaturated vadose zone soil. A vacuum is applied to the soil to induce the controlled flow of air and remove volatile and some semivolatile organic contaminants from the soil. SVE usually is performed in situ; however, in some cases, it can be used as an ex situ technology.
soil washing is an ex situ soil or sediment treatment technology. Contaminants sorbed onto fine soil particles are separated from bulk soil in a water-based system on the basis of particle size. The wash water may be augmented with a basic leaching agent, surfactant, or chelating agent or by adjustment of pH to help remove organics and heavy metals. Soils and wash water are mixed ex situ in a tank or other treatment unit. The wash water and various soil fractions are usually separated using gravity settling.
Soil washing is an ex situ soil or sediment treatment technology. Contaminants sorbed onto fine soil particles are separated from bulk soil in a water-based system on the basis of particle size. The wash water may be augmented with a basic leaching agent, surfactant, or chelating agent or by adjustment of pH to help remove organics and heavy metals. Soils and wash water are mixed ex situ in a tank or other treatment unit. The wash water and various soil fractions are usually separated using gravity settling.
soil water is held in the pore spaces between particles of soil. Soil water is the water that is immediately available to plants. Soil water can be further sub-divided into three categories, 1) hygroscopic water, 2) capillary water, and 3) gravitational water.
Hygroscopic water is found as a microscopic film of water surrounding soil particles. This water is tightly bound to a soil particle by molecular attraction so powerful that it cannot be removed by natural forces. Hygroscopic water is bound to soil particles by adhesive forces that exceed 31 bars and may be as great as 10,000 bars (Recall that sea level pressure is equal to 1013.2 millibars which is just about 1 bar!).
Capillary water is held by cohesive forces between the films of hygroscopic water. The binding pressure for capillary water is much less than hygroscopic water. This water can be removed by air drying or by plant absorption, but cannot be removed by gravity. Plants extract this water through their roots until the soil capillary force (force holding water to the particle) is equal to the extractive force of the plant root. At this point the plant cannot pull water from the plant-rooting zone and it wilts (called the wilting point).
Gravity water is water moved through the soil by the force of gravity. The amount of water held in the soil after excess water has drained is called the field capacity of the soil. The amount of water in the soil is controlled by the soil texture. Soils dominated by clay-sized particles have more total pore space in a unit volume than soils dominated by sand. As a result, fine grained soils have higher field capacities than coarse-grained soils.
There is a relationship between soil texture, wilting point, field capacity, and available water. The difference between the wilting point and the field capacity is the available water. The smallest amount of available water is associated with the coarsest soil texture, sand. The amount of available water increases where soils with a mixture of different sized particles (loamy soils) are found. The available water then drops off toward the fine textured soils on the right. How does one explain the relationship between available water and soil texture? Coarse soil does not have much available water because it doesn't hold much water to begin with. At the other end of the spectrum, low available water in fine soils is due to strong bond between soil particles and water. Plants have a harder time pulling water away from the soil particle under these conditions.
soil is generally defined as the top layer of the earth’s crust. It is formed by mineral particles, organic matter, water, air and living organisms. Soil is the interface between the earth (geosphere), the air (atmosphere) and the water (hydrosphere). While soil is the physical upper layer of what is usually referred to as “land”, the concept of “land” is much wider and includes territorial and spatial dimensions. It is difficult to separate soil from its land context. (Source: EUGRIS)
solar photovoltaics (PVs) are arrays of cells containing a material, such as silicon, that converts solar radiation into electricity. Today solar PVs are used in a wide range of applications, from residential rooftop power generation to medium-scale utility-level power generation.
The Concentrated Solar Power (CSP) systems use mirrors or reflective lenses to focus sunlight on a fluid to heat it to a high temperature. The heated fluid flows from the collector to a heat engine where a portion of the heat is converted to electricity. Some types of CSP allow the heat to be stored for many hours so that electricity can be produced at night.
the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, andsolar radiation is obvious as daylight when the Sun is above the horizon.
Sunlight is a key factor in photosynthesis, a process vital for life on Earth. The existence of nearly all life on Earth is fueled by light from the sun. Most autotrophs, such as plants, use the energy of sunlight, combined with minerals and air, to produce simple sugars—a process known as photosynthesis. These sugars are then used as building blocks and in other synthetic pathways which allow the organism to grow.
Heterotrophs, such as animals, use light from the sun indirectly by consuming the products of autotrophs, either directly or by consuming other heterotrophs. The sugars and other molecular components produced by the autotrophs are then broken down, releasing stored solar energy, and giving the heterotroph the energy required for survival. This process is known as respiration.
The more recent discoveries of coal, petroleum and natural gas are modern extensions of this trend. These fossil fuels are the remnants of ancient plant and animal matter, formed using energy from sunlight and then trapped within the earth for millions of years.
Solar energy arrives on the surface from two sources: direct sunlight and diffuse background-radiation from the sky. The solar constant of the radiation on the outer border of the atmosphere is 8,123 Jcm-2min-1, but out of this only 5.44 Jcm-2min-1 can reach the surface (see level), because the difference is reflected into space (albedo). Decrease of albedo (for example due to CO2 accumulation in the atmosohere) causes an increase in the temperature of Earth (green-house effect).
The spectrum of the Sun's solar radiation is close to that of a black body with a temperature of about 5,800 K. About half that lies in the visible short-wave part of the electromagnetic spectrum and the other half mostly in the near-infrared part. Some also lies in the ultraviolet part of the spectrum. When ultraviolet radiation is not absorbed by the atmosphere or other protective coating, it can cause damage to the skin known as sunburn or trigger an adaptive change in human skin pigmentation.
The spectrum of electromagnetic radiation striking the Earth's atmosphere is 100 to 106 nanometers (nm). This can be divided into five regions in increasing order of wavelengths:
- Ultraviolet C or (UVC) range, which spans a range of 100 to 280 nm.
- Ultraviolet B or (UVB) range spans 280 to 315 nm. I
- Ultraviolet A or (UVA) spans 315 to 400 nm.
- Visible range or light spans 400 to 700 nm. For the photosynthesis useful range is 380 nm to 740 nm.
- Infrared range that spans 700 nm to 106 nm [1 mm]. It is responsible for an important part of the electromagnetic radiation that reaches the Earth. It is also divided into three types on the basis of wavelength:
- Infrared-A: 700 nm to 1,400 nm
- Infrared-B: 1,400 nm to 3,000 nm
- Infrared-C: 3,000 nm to 1 mm.
a solar thermal collector is a solar collector designed to collect heat by absorbing sunlight. The term is applied to solar hot water panels, but may also be used to denote more complex installations such as solar parabolic, solar trough and solar towers or simpler installations such as solar air heat. The more complex collectors are generally used in solar power plants where solar heat is used to generate electricity by heating water to produce steam which drives a turbine connected to an electrical generator. The simpler collectors are typically used for supplemental space heating in residential and commercial buildings. A collector is a device for converting the energy in solar radiation into a more usable or storable form.
Flat plate thermal system for water heating deployed on a flat roof. They consist of a dark flat-plate absorber of solar energy, a transparent cover that allows solar energy to pass through but reduces heat losses, a heat-transport fluid (air, antifreeze or water) to remove heat from the absorber, and a heat insulating backing. The absorber consists of a thin absorber sheet (of thermally stable polymers, aluminum, steel or copper, to which a matte black or selective coating is applied) often backed by a grid or coil of fluid tubing placed in an insulated casing with a glass or polycarbonate cover. In water heat panels, fluid is usually circulated through tubing to transfer heat from the absorber to an insulated water tank. This may be achieved directly or through a heat exchanger. Most air heat fabricates and some water heat manufacturers have a completely flooded absorber consisting of two sheets of metal which the fluid passes between. Because the heat exchange area is greater they may be marginally more efficient than traditional absorbers.
Another type of collector is vacuum tube collector: it uses heat pipes for its core instead of passing liquid directly through it. Evacuated heat pipe tubes (EHPT's) are composed of multiple evacuated glass tubes each containing an absorber plate fused to a heat pipe. The heat from the hot end of the heat pipes is transferred to the transfer fluid (water or an antifreeze mix—typically propylene glycol) of a domestic hot water or hydronic space heating system in a heat exchanger called a "manifold". The manifold is wrapped in insulation and covered by a sheet metal or plastic case to protect it from the elements.
Source: http://en.wikipedia.org/wiki/Solar_thermal_collector
a chromatographic technique used to prepare samples for subsequent analysis, an effective method to concentrate or isolate the non-volatile analytes. It is a kind of column chromatography. The extract is eluted through the column (cartridge) containing the preconditioned sorbent by applying vacuum. The substance of interest is retained on the column and all the interfering components are eluted or the interfering components are retained and the substance of interest is eluted. This sample preparation technique is suitable for any compounds. The low solvent need, no need of concentration by evaporation and in this way avoiding the concentration of the polluting components, cheap sorbents, saving time, no emulsion formation, enhanced selectivity and potential for automatization are the advantages of SPE over the traditional liquid/liquid extraction (LLE).
A solvent is a liquid or gas that dissolves a solid, liquid, or gaseoussolute, resulting in a solution.To distinguish between solutes and solvents, solvents are usually present in the greater amount.
The most common solvent in everyday life is water.
Commonly-used solvents are the organic solvents, which usually have low boiling point, can easily be removed by destillation or evaporation. solvents are usually clear and colorless liquids and many have a characteristic odor.
Common uses for organic solvents are in dry cleaning (tetrachloroethylene), as paint thinners, as nail polish removers and glue solvents (acetone, methyl acetate, ethyl acetate), in spot removers (e.g. hexane, petrol-ether), etc. In 2005, the worldwide market for solvents had a total volume of around 17.9 million tons, which led to a turnover of about 8 billion Euro.
a noise caused by a shock wave (a propagating disturbance) that emanates from an aircraft or other object traveling at or above sonic velocity.
sorption refers to the action of both absorption and adsorption taking place simultaneously. sorption means the incorporation of gases or liquids into a material of a different physical phase (gas into liquid, or liquid into solid) by adhering into the matrix or onto the surface.
In environmental transport processes we can hardly distinguish between absorption and adsorption, so that the use of the term sorption prevails.
diffusion into the environment of a sound emitted from a given source.
the introduction in the environment of noise deriving from various sources that can be grouped in: transportation activities, industrial activities and daily normal activities.
an extraction technique of solids in which the sample is repeatedly contacted with solvent over several hours, increasing the extraction efficiency. Soxhlet extraction is a purification technique developed by Franz von Soxhlet in 1879. The solid is put into a paper "thimble" which is then placed into the main chamber of the Soxhlet extractor. The solvent is heated to reflux and then travels up the distillation arm and floods into the main chamber with the thimble. The chamber then slowly fills and some of the pure compound will dissolve into the solvent. The chamber is emptied with the help of the side arm and the cycle repeats. See also http://chemistry.hull.ac.uk/labweb/glossary_soxhlet.php#
space debris, also known as orbital debris, space junk and space waste, is the collection of objects in orbit around Earth that were created by humans but no longer serve any useful purpose. These objects consist of everything from spent rocket stages and defunct satellites to explosion and collision fragments. The debris can include slag and dust from solid rocket motors, surface degradation products such as paint flakes, coolant released by RORSAT nuclear powered satellites, clusters of small needles, and objects released due to the impact of micrometeoroids or fairly small debris onto spacecraft.[1] As the orbits of these objects often overlap the trajectories of spacecraft, debris is a potential collision risk.
The vast majority of the estimated tens of millions of pieces of space debris are small particles, like paint flakes and solid rocket fuel slag. Impacts of these particles cause erosive damage, similar to sandblasting. The majority of this damage can be mitigated through the use of a technique originally developed to protect spacecraft from micrometeorites, by adding a thin layer of metal foil outside of the main spacecraft body. Impacts take place at such high velocities that the debris is vaporized when it collides with the foil, and the resulting plasma spreads out quickly enough that it does not cause serious damage to the inner wall. However, not all parts of a spacecraft may be protected in this manner, i.e. solar panels and optical devices (such as telescopes, or star trackers), and these components are subject to constant wear by debris and micrometeorites.
The present means for spacecraft shielding, such as those used for the manned modules of the International Space Station, are only capable of protecting against debris with diameters below about 1 centimetre (0.39 in). The only remaining means of protection would be to maneuver the spacecraft in order to avoid a collision. This, however, requires that the orbit of the respective object be precisely known. The current equipment used to gather such information is only capable of tracking objects down to about 5 centimetres (2.0 in) diameter in low Earth orbit, and about 50 centimetres (20 in) in geosynchronous orbit. Out of the estimated 600,000 objects[1] above 1 centimetre (0.39 in) diameter, only 19,000 can be tracked as of today. This leads to wide uncertainties in the estimated quantities of debris, and the predicted path of their orbits.
If a collision with larger debris does occur, many of the resulting fragments from the damaged spacecraft will also be in the 1 kilogram (2.2 lb) mass range, and these objects become an additional collision risk. As the chance of collision is a function of the number of objects in space, there is a critical density where the creation of new debris occurs faster than the various natural forces that remove these objects from orbit. Beyond this point a runaway chain reaction can occur that quickly reduces all objects in orbit to debris in a period of years or months. This possibility is known as the "Kessler Syndrome", and there is debate as to whether or not this critical density has already been reached in certain orbital bands.
Source: http://en.wikipedia.org/wiki/Space_debris
species of Community interest means species which, within the territory referred to in Article 2, are:
(i) endangered, except those species whose natural range is marginal in that territory and which are not endangered or vulnerable in the western palearctic region; or
(ii) vulnerable, i.e. believed likely to move into the endangered category in the near future if the causal factors continue operating; or
(iii) rare, i.e. with small populations that are not at present endangered or vulnerable, but are at risk. The species are located within restricted geographical areas or are thinly scattered over a more extensive range; or
(iv) endemic and requiring particular attention by reason of the specific nature of their habitat and/or the potential impact of their exploitation on their habitat and/or the potential impact of their exploitation on their conservation status.
Such species are listed or may be listed in Annex II and/or Annex IV or V;
Source: Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora.
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31992L0043:EN:html
Species Sensitivity Distribution (SSD) method is based on statistical extrapolation and aims to determine the predicted no effect concentration of a chemical substance, which does not effect the ecosystem.
If a large data set with No Observed Effects Concentrations, NOECs from long-term experiments for different taxonomic groups is available, these values can be used to draw the distribution curve. This distribution that describes the variability of hazard of a substance to organisms is called a Species Sensitivity Distribution (SSD). This distribution can be presented as a frequency distribution (cumulative normal distribution curves or other similar distribution curves) of NOEC values for species. From this curve we can read Xm, the mean toxicity expressed as the mean NOEC value of a substance. The Sm represents the toxicity range or variation in sensitivity of a substance.
The main assumption on the use of SSDs in risk assessment is that the distribution based on a selection of species (tested in laboratory experiments) are representative for all species (in the field).