Residual deposits

Barite [13462-86-7], natural barium sulfate, BaSO, commonly known as barytes, and sometimes as heavy spar, tiU, or cawk, occurs in many geological environments in sedimentary, igneous, and metamorphic rocks. Commercial deposits are of three types vein and cavity filling deposits residual deposits and bedded deposits. Most commercial sources are replacement deposits in limestone, dolomitic sandstone, and shales, or residual deposits caused by differential weathering that result in lumps of barite enclosed in clay. Barite is widely distributed and has minable deposits in many countries. 

Firing tests with the other cal handgnns indicated distinguishable differences in the overall distribution patterns of discharge residues from different handguns. This unique distribution pattern of residues deposited immediately below the flight path of the bullet results from the cloud of combustion products emitted thru the barrel of/the weapon. 

PET powder was prepared from commercial PET bottles and had a number-average molecular weight of 30,000. PET powder (0.2 g) was placed in 30 mL of relatively dilute sulfuric acid (10 M) in a sealed Pyrex tube and heated to 150°C for 1-6 h in an oven. After the reaction mixture was allowed to cool, the precipitate of TPA and PET residue deposited was filtered through a 1G-5 glass filter. TPA was separated as the ammonium salt by dissolving it in 12 mL of 5 M NH3. The TPA was reprecipitated by sulfuric acid solution. The yield of TPA was 100% in 10 M sulfuric acid solution. 

Depending on the mode of origin, four main types of sedimentary ore deposits are recognized. These are (i) mechanical accumulations or placer deposits, (ii) residual deposits, (iii) syn-sedimentary chemical deposits, and (iv) volcano-sedimentary type deposits. 

Four tests were employed against houseflies the standard Peet-Grady method (1) the turntable method (2) the loop method, in which the material is applied to individual female houseflies, by means of a calibrated wire loop (9) and a residual deposit test, in which flies are exposed to glass plates 25 hours after they have been sprayed with acetone solutions of the products. 

Because of the importance of safe insecticides in the protection of foods, additional tests have been run against German cockroaches, red flour beetles, and Mexican bean beetle larvae. The residual deposit test was used on the first two insects, and a dust test on the bean beetles. The procedure for the latter method is to incorporate the materials into dusts which are distributed on bean leaves (6) piperonyl cyclonene, which is superior to butoxide against this insect, was included in this series of tests. 

The determination of DDT residue on apples grown in the Hood River fruit district and on pears at Medford is carried on in branch laboratories established in those areas. The majority of samples selected for analyses are suspected of carrying higher amounts of residue than the average because of the spray program used or because the last application of insecticide was made within a few weeks of harvest. As indicated by Table I, about 80% of all the samples analyzed carried 3.0 p.p.m. or less of DDT during the past harvest season. Only about 20% of the samples showed residues above 3.0 p.p.m. six samples showed residue deposits slightly above 7.0 p.p.m. 

A matter of very great interest is the increase in resistance to DDT that has been shown recently by houseflies in various parts of the world. This is often so marked that practical use of DDT is no longer feasible. An especially resistant strain, found in southern California by March and Metcalf, is called the Bellflower strain for purposes of identification (4). They reported that no residual deposit of DDT gave 100% kill. By the small vial method not over 25% kill of these female flies could be obtained with several thousand micrograms per vial. Further tests with various naturally occurring and selected resistant races are in progress. 

With some insecticides the physical state of a residual deposit has a pronounced effect upon its toxic effect. This is especially true of technical DDT, which tends to remain in viscous droplets when released from solution in volatile solvents. These may remain... 

To date, within the scope of the writers information, there has been no residual deposit or poison residue recovered from treated fruits or vegetables, where proper formulations and amounts of the pure gamma isomer have been used not later than 2 weeks prior to crop harvest. Likewise, there is no known record of poisoning to man or animals from applying the insecticide or eating food treated with the insecticide. Freedom from poisonous residue and undesirable taste in the use of the pure gamma isomer of hexa-chlorocyclohexane is achieved therfeore by proper formulation, timing, and application of insecticide treatments. 

The residues deposit causes a reduction in the material permeability during the DPF life. This phenomenon leads to an increase in the exhaust back pressure, and is noticeably more marked when the soot quantity trapped in the DPF increases (see Figure 7.9). 

Because half-lives may vary substantially, the values of the actual DFR available for transfer to the worker will diverge with prolonged re-entry time. For example, the difference between the actual DFRs will increase approximately 3% per day for both pesticides in our study. These pesticides have long half-lives which differ by a factor of 2, assuming a similar initial residue deposit therefore, the half-life of a pesticide must be considered a critical factor for the level of re-entry exposure. Increase of re-entry time will decrease the transfer factor however, the decrease observed in this study is small and negligible compared to all other factors and variances that influence re-entry exposure. 

A detection of p-isomer HCH in water in relatively larger quantities in comparison with other isomers shows a high degree of insecticide transformation in the soil (mainly by microorganisms), and hence loss or leaching of insecticide residues deposited some decades ago. It is known that p-isomer HCH is the most stable compound among others of HCH isomers, i.e., it is not or very weakly exposed to elimination reaction—dehydrochlorination (Cristol, 1947). High persistence of HCH p-isomer is... 

Deep-well injection of the gas may force briny water to the surface, potentially polluting streams and aquifers. Earthquakes have also been reported in places where deep-well injection has occurred and carbon dioxide can convert to an acid in groundwater. Carbon storage provides a unique advantage, buried in an oil field, the gas boosts oil production by forcing residual deposits to the surface. At Weyburn, oil production is up 50% since carbon dioxide injection began four years ago. 

Clark DE. 1977. The effect of hexachlorobenzene on in vivo biotransformation, residue deposition, and elimination of certain exogenous compounds and on body weight and organ weight in the rat. Dissertation Abstracts International B-The Sciences and Engineering 37(12 Pt.1) 6087-B. 

Apart from the use of practical explosive tests to assess damage patterns at a crime scene, it has been suggested that patterns of deposition of explosives residue could be similarly assessed [27]. Practical experience shows that even in a planned scientific experiment there are huge variations in residue deposition patterns because of the difficulty of controlling aU the relevant parameters. Events at a crime scene are completely uncontrolled and subject to even greater variations, and to make matters worse the design, placement and performance of the explosive device are at best inferred rather than known. The presence of chemical traces of a particular explosive at a bomb scene is a useful indication of the material used the drawing of any conclusions beyond that point should be subject to extremely cautious consideration. 

During this step, a preliminary analysis of the parts is performed. Typically, the focus is a visual examination of the items. The investigators should avoid disturbing data until necessary, conducting their visual examination without alterations. Take pictures of the items and mark positions in the field if immediate removal is necessary. Remove the parts in a controlled, careful, and methodical manner. Evaluate the importance of coatings/residues/deposits/impurities. Samples of the chemicals, soil, deposits, and coatings may be taken at this point. 

Talma AS, Netterberg F (1983) Stable isotope abundances in calcretes. In Residual Deposits Surface Related Weathering Processes and Materials. Wilson, RCL (ed) Oxford Blackwell Scientific Publ., p 221-233 Tian L, Masson-Delmotte V, Stievenard M, Tao T, Jouzel J (2001) Tibetan Plateau summer monsoon northward extent revealed by measurements of water stable isotopes. J Geophys Res 106 28,081-28,088 Tian L, Yao T, White JWC, Yu W, Wang N (2005) Westerly moisture transport to the middle of Himalayas revealed from the high deuterium excess. Chinese Sci Bull 50 1026-130 Uba CE, Heubeck C, Hulka C (2006) Evolution of the late Cenozoic Chaco foreland basin, southern Bolivia. Basin Res 18 145-170... 

Evidence was obtained recently that pesticide vapors may enter the air by still another mechanism, involving plant circulation and water loss (57). Rice plants were found to efficiently transport root-zone applied systemic carbamate insecticides via xylem flow to the leaves, eventually to the leaf surface by the processes of guttation and/or stomatal transpiration, and finally to the air by surface volatilization. Results from a model chamber showed that 4.2, 5.8, and 5.7% of the residues of carbaryl, carbofuran, and aldicarb, respectively, present in rice plants after root soaking vaporized within 10 days after treatment. The major process was evaporation of surface residues deposited by guttation fluid. 

Bulk elemental analysis methods have been employed by many workers to do quantitative studies of the amount of residue deposited on the firing hand. 

Bisjdiphenyl Tellurium 4-Bromo-2-fomtylphcnoxlde] Oxide1 A solution of 19.89 g (0.1 mol) of 5-bromo-2-hydroxybenzaldehyde in 50 ml benzene is added within 5 min to a suspension of 29.76 g (0.1 mol) of diphenyl tellurium oxide in 200 ml benzene. The mixture is refluxed until 0.9 m/water are collected in a Dean-Stark trap. Most of the solvent is distilled from the reaction mixture. The residue deposits on cooling to 5" bright yellow crystals yield 98% m.p. 75° (from carbon tetrachloride). 

Dermal exposure The quantifiable measure of the amount of residue deposited on skin, normally expressed as a density, or mass per unit time, deposited on a defined skin surface area (e.g. mg/h hand exposure) equivalent to potential dose for the dermal route (USEPA, 1998). 

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