The collapse of major histocompatiblity complex (MHC) class-I-dependent immune privilege can lead to autoimmune disease or fetal rejection. Pragmatic and instructive models are needed to clarify the...Full Text Available
The eye is an easily accessible, highly compartmentalised and immune-privileged organ that offers unique advantages as a gene therapy target. Significant advancements have been made in understanding...Full Text Available
We present a technique for identifying the amino acids responsible for a loss of immunoreactivity in response to treating an antigen with a chemical modifier. This is of particular interest...Full Text Available
It is shown that the existence of faster-than-light signals (tachyons) would imply the existence (and detectability) of a privileged inertial frame and that one can avoid all problems with reversed-time order only by using absolute synchronization instead of the standard one. The connection between these results and the EPR-paradox is discussed.
Due to the large number of chemicals in commerce without adequate toxicity characterization data, coupled with an ineffective federal policy for chemical management in the United States, many states are grappling with the challenge to identify toxic chemicals that may pose a risk to human health and the environment. Specific populations (e.g., children, elderly) are particularly sensitive to these toxic chemicals. In 2008, the Children's Safe Product Act (CSPA) was passed in Washington State. The CSPA included specific requirements to identify High Priority Chemicals (HPCs) and Chemicals of High Concern to Children (CHCCs). To implement this legislation, a methodology was developed to identify HPCs from authoritative scientific and regulatory sources on the basis of toxicity criteria. Another set of ...
Many lessons in autoimmunity — particularly relating to the role of immune privilege and the interplay between genetics and neuroimmunology — can be learned from the study of alopecia...Full Text Available
These Appendices describe various technologies that may be applicable to the Mixed Waste Treatment Plant (MWTP) Chemical/Physical Treatment System (CPTS). These technologies were identified by the CPTS Technical Support Group (TSG) as potentially applicable to a variety of separation, volume reduction, and decontamination requirements. The purpose was to identify all available and developing technologies, and their characteristics, for subsequent evaluation for specific requirements identified for the CPTS. However, the technologies described herein are not necessarily all inclusive, nor are they necessarily all applicable.
The Los Alamos Nuclear Material Accounting and Safeguards System (MASS) is a near-real-time accountability system for bulk materials, discrete items, and material undergoing dynamic processing. MASS has evolved from an eighty-column card based process control system to a very sophisticated computer system. The security of the MASS computer system is provide through various access controls. There are two kinds of access control to be addressed. They are physical access control to the hardware which make up the system, and access control to the software. There are many features which provide a measure of security to the hardware that will be discussed. Access to the software is controlled by a security password. Access to various transaction activities in the system is controlled through the level of MASS user privilege. Details of MASS user privilege will be discussed.
DescriptionThis project has two independent aims: (1) to investigate the use of struvite as an alternative to chemical P fertilisers and (2) to develop an oligonucleotide microarray to monitor the P status of the potato crop. The UK horticultural and agricultural industries rely on large inputs of phosphate (P) fertilisers to maintain crop yields and quality. However, the use of non-renewable, chemical P fertilisers is unsustainable, and the alternatives to chemical P-fertilisers must be identified as an [continued...
Objectives1. To establish the present capacity and capability across all the sectors within the UK for - a) Undertaking research in the areas of toxicology and ecotoxicology and environmental hazard and risk assessment work on chemical subtances including emerging containments (e.g. enginerred nanomaterials); and b) Applying these skills in the policy and regulatory context. 2) The range of chemicals involved should include pharmaceutical and medical products, crop protection agents, biocides, vet [continued...]DescriptionThe aim of this project is to identify the current status of the scientific community, areas of expertise, and identify the gaps in skills, knowledge or recruitment. The project will use a questionnaire approach to obtain this information for all sectors of the business community. The analysis will identify the gaps in provision, and areas where investment is ...
"Nine of CERN 's 20 Member States today a signed new Protocol on privileges and immunities. This brings the Organization into line with other European intergovernmental organizations, such as the European Space Agency and the European Southern Observatory, which already enjoy international status in all of their Member States" (2
A light-sensitive vitamin B12 derivative has been extracted from the adult cestode, Spirometra mansonoides. This corrinoid was identified as the cobamide coenzyme, adenosylcobalamin, by its chromatographic, chemical, and spectral properties. PMID:1003284
Fish living in contaminated environments accumulate toxic chemicals in their tissues. Biomarkers are needed to identify the resulting health effects, particularly focusing on early changes at a subcellular...Full Text Available
BackgroundOceans are iron-deficient and nutrient-poor environments. These conditions impart limitations on our understanding of and our ability to identify microorganisms from the...Full Text Available
An important early step in the assessment of ecological risks at contaminated sites is the screening of chemicals detected on the site to identify those that constitute a potential risk. Part of this screening process is the comparison of measured ambient concentrations to concentrations that are believed to be nonhazardous, termed benchmarks. This article discusses 13 methods by which benchmarks may be derived for aquatic biota and presents benchmarks for 105 chemicals. It then compares them with respect to their sensitivity, availability, magnitude relative to background concentrations, and conceptual bases. This compilation is limited to chemicals that have been detected on the US Department of Energy's Oak Ridge Reservation (ORR) and to benchmarks derived from studies of toxic effects on freshwater organisms. The list of chemicals includes 45 metals and 56 industrial organic ...
Under Section 5 of the Toxic Substances Control Act (TSCA), manufacturers must notify the US Environmental Protection Agency (EPA) 90 days before manufacturing, processing, or importing a new chemical substance. This is referred to as a premanufacture notice (PMN). The PMN must contain certain information including chemical identity, production volume, proposed uses, estimates of exposure and release, and any health or environmental test data that are available to the submitter. Because there is no explicit statutory authority that requires testing of new chemicals prior to their entry into the market, most PMNs are submitted with little or no data. As a result, EPA has developed special techniques for hazard assessment of PMN chemicals. These include (1) evaluation of available data on the chemical itself, (2) evaluation of data on analogues of the PMN, or evaluation of data on ...
The point at which the common final pathway for induction of cancer by chemical carcinogens and ionizing radiation has not been identified. Although common molecular targets are suggested by recent findings about the role of oncogenes, the mechanism by which the deposition of radiation energy and the formation of adducts or other DNA lesions induced by chemicals affects the changes in the relevant targets may be quite different. The damage to DNA that plays no part in the transformation events, but that influences the stability of the genome, and therefore, the probability of subsequent changes that influence tumorigenesis may be more readily induced by some agents than others. Similarly, the degree of cytotoxic effects that disrupt tissue integrity and increase the probability of expression of initiated cells may be dependent on the type of carcinogen. Also, evidence was presented that repair of the initial lesions could ...
It is known that the plant cuticle represents the first barrier that must be overcome by any chemical reaching the plant surface from the atmosphere before entering the plant. Because of the importance of the cuticle as a barrier to penetration of a wide variety of compounds, its morphology, chemistry, and permeability have been extensively studied. However, only limited information is available on the nature of functional chemical groups present and their interaction and role during the penetration process. The usefulness of in situ Fourier transform infrared spectroscopy studies in identifying functional groups present in isolated cuticles is described and their relationships to the structure of the cuticular membrane are discussed. Applications of infrared spectroscopy on the presence and role of phenolics in the cuticle structure and during the cuticle development, nitrogen oxide binding to isolated cuticles, and the ...
A detailed chemical kinetic reaction mechanism is developed to describe incineration of the chemical warfare nerve agent sarin (GB), based on commonly used principles of bond additivity and hierarchical reaction mechanisms. The mechanism is based on previous kinetic models of organophosphorus compounds such as TMP, DMMP and DIMP that are often used as surrogates to predict incineration of GB. Kinetic models of the three surrogates and GB are then used to predict their consumption in a perfectly stirred reactor fueled by natural gas to simulate incineration of these chemicals. Computed results indicate that DIMP is the only one of these surrogates that adequately describes combustion of GB under comparable conditions. The kinetic pathways responsible for these differences in reactivity are identified and discussed. The most important reaction in GB and DIMP that makes them more reactive than TMP or DMMP ...
Based on an multivariate statistical evaluation of binary and metric data relating to the soil cover of the European Community five regionally representative reference soils (EURO-Soils) have been identified for chemicals testing in the EC. The soil material sampled at representative localities in Italy, Greece, Great Britain, France and Germany was treated and prepared according to OECD Test Guideline 106 and analysed in detail. The homogenised specimens were subject to an EC-wide ring test to evaluate the feasibility of the modified guideline and to validate the physical-chemical amenability of the reference soils for sorption tests. The results proved the validity of the soils selected for assessing the potential behaviour of new chemicals in soil on the basis of a comparative evaluation of the individual test results obtained. In the light of this parametric assessment potential test soils were ...
This report identifies individual contaminants and contaminant mixtures that have been measured in the ground at 91 waste sites at 18 US Department of Energy (DOE) facilities within the weapons complex. The inventory of chemicals and mixtures was used to identify generic chemical mixtures to be used by DOE's Subsurface Science Program in basic research on the subsurface geochemical and microbiological behavior of mixed contaminants (DOE 1990a and b). The generic mixtures contain specific radionuclides, metals, organic ligands, organic solvents, fuel hydrocarbons, and polychlorinated biphenyls (PCBs) in various binary and ternary combinations. The mixtures are representative of in-ground contaminant associations at DOE facilities that are likely to exhibit complex geochemical behavior as a result of intercontaminant reactions and/or microbiologic activity stimulated by organic substances. Use of ...
This study describes the chemical composition of the essential oil of Artemisia maritima (Am.Oil) and the pharmacological basis for its medicinal use in gut and airways disorders. Twenty five compounds, composing 93.7% of the oil, were identified; among these, chrysanthenyl propionate and elixene were identified for the first time from any Artemisia species. The Am.Oil (0.3?1.0 mg/mL) suppressed spontaneous and high K+ (80 mM)-induced contractions in isolated rabbit jejunum, suggestive of an antispasmodic effect mediated possibly through calcium channel blockade. The calcium channel blockade activity was confirmed when pre-treatment of the tissue with Am.Oil (0.01?0.03 mg/mL) shifted the Ca++ concentration-response curves to the right, similar to verapamil and papaverine. In isolated trach...
The chemical state of iron contained in several kinds of bauxite, which are utilized as a raw material in the aluminum industry in Japan, were investigated by Moessbauer spectroscopy. The main compounds of iron were identified from the results, which showed variations of the Moessbauer absorption spectra with calcination and measuring temperature. Although the absorption intensities of the spectra differed significantly, major species identified were paramagnetic or superparamagnetic #alpha#-Fe_2O_3 in all of these bauxite samples. The superparamagnetic #alpha#-Fe_2O_3 was found mainly in the gibbsite-type bauxite, but not in the boehmite/gibbsite-type or the boehmite-type bauxite. The Moessbauer absorption spectra of red mud and its calcined products were also given. (author).
Based on the instrumental wavelength dispersive X-ray fluorescence technique of analysis (W D-X R F), the inorganic elements in four samples of commercial medicines drugs were analyzed. The samples were used without any chemical separation of the elements or chemical pre-treatment. Eleven elements could be identified, namely Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu and Zn. However, Si, Ti and Mn have not been mentioned in the printed instructions for the use of the medicines drugs by the producers. (author)
This paper describes the chemical constituents isolated from aerial parts of the plant Galianthe brasiliensis. From a methanol extract, the iridoid glycosides asperuloside, deacetylasperuloside, mixture of Z- and E-6-O-p-coumaroylscandoside methyl ester, the triterpene ursolic acid and the steroids stigmasterol, campesterol, b-sitosterol and 3-O-b-glucopyranosyl sitosterol were isolated. The structures of the natural products were identified on the basis of spectral data, including 2D NMR experiments. The antiproliferative properties of the crude methanolic extract were investigated against a series of nine human cancer cell lines. (author)
In order to apply chemical-looping combustion to a practical power plant, carbon deposition on the solid particle is one of the key problems to be overcome. Six kinds of solid particles were examined to clarify the kinetic behavior of carbon deposition. The effects of the solid composition, feed gas composition, and reaction temperature on carbon deposition were investigated by thermogravimetrical reactor on the basis of NiO/YSZ particle. From the viewpoints of both reactivity and resistance against carbon deposition, the particle of NiO mixed with YSZ (i.e., yttria-stabilized zirconia) was found to be a good candidate for chemical-looping combustion. It has been observed that carbon deposition could be completely avoided with very low concentration of water vapor. By means of a proposed model, the condition that carbon deposition would be avoided was identified. 12 refs., 8 figs., 2 tabs.
A considerable amount of chemical knowledge of marine sediments has been acquired in recent years but has not yet been utilized by paleomagnetists. On the other hand, geochemists are often unaware of the usefulness of numerous magnetic techniques. In this review we try to bridge this gap, and in particular, we outline many of the chemical and magnetic principles that should allow paleomagnetists to better identify and undertand chemical changes that affect the magnetic properties of marine sediments. The chemical principles include those for distinguishing the four major sources of sediments (continental, biological, authigenic/hydrogenous, volcanic/hydrothermal) from one another by determining elemental abundance distributions, as well as for investigating the stabilities of mineral phases relative to changes in pE and pH. The magnetic principles include the effects of authigenesis ...
Highlights of the meeting are briefly summarized in this paper. Most of the papers presented at the meeting dealt with remediation and pollution prevention practices. A major focus of the technical sessions was on the identification of pollution sources. Identification of exposures to specific chemicals with disease outcomes was also discussed. Other papers focused on ecological exposures and their effects on wildlife to identify the presence of contaminants. 4 refs.
The carcinogenicity database used for this paper originated in the late 1960s by the National Cancer Institute (NCI) and since 1978 has been continued and made more comprehensive by the National Toxicology...Full Text Available
DescriptionEnzymes are natural catalysts that are used increasingly to replace environmentally harmful chemicals and to achieve better catalytic selectivity during pulp and paper processing. The main objective of this project is to identify novel plant enzymes for deeper understanding of the process of fibre formation and for future improvement of the quality parameters of wood fibres. Specific modification of the fibre characteristics will facilitate their use as raw materials for the current pulp and pap [continued...
Research on and with ethnic minority students is characterised by a growing international literature that privileges 'liberal multiculturalism' as a lens through which to understand their experiences, yet ethnic diversity is constructed and responded to in many societies that are not underpinned by liberal democratic values. In this paper we use Joppke's binary to show how researching ethnic minority students outside of a liberal democratic framework requires methodologies that enable researchers to see beyond the invisibility that is often attached to ethnic minorities. We show how invisibility (i.e. antidiscrimination) can also be further culturally constructed, confounding even more any broader multicultural project. We canvass four broad areas including the role of legally binding legi...
We outline a neo-Meinongian framework labeled as Modal Meinongian Metaphysics (MMM) to account for the ontology and semantics of fictional discourse. Several competing accounts of fictional objects are originated by the fact that our talking of them mirrors incoherent intuitions: mainstream theories of fiction privilege some such intuitions, but are forced to account for others via complicated paraphrases of the relevant sentences. An ideal theory should resort to as few paraphrases as possible. In Sect.?1, we make this explicit via two methodological principles, called the Minimal Revision and the Acceptability Constraint. In Sect.?2, we introduce the standard distinction between internal and external fictional discourse. In Sects.?3?5, we discuss the approaches of (traditional) Meinongia...
This article examines the successive reinterpretations of one of Cuba?s foundational texts, namely the Espejo de paciencia (?Model of Patience??, 1608) by Silvestre de Balboa, as a baroque poem. The revalorization of the baroque by twentieth-century Cuban authors and critics has been explained as a consequence of the erasure of indigenous cultures and the subsequent imposition of a metropolitan culture. In this sense, the baroque is supposed to be paradigmatic for ?roots thinking?? about nation-building and culture. The readings of Balboa?s poem by neo-baroque writers such as Jos? Lezama Lima, Cintio Vitier and Severo Sarduy, however, put forward a transhistorical vision of the baroque and Cubanhood as an eternal and immutable phenomenon or, alternatively, a reading that privileges the tec...
A fully lamellar ferrite/cementite nanostructure was designed in a low C steel by using a specific thermal treatment. The strengthening of such microstructure has been investigated as a function of prestrain by rolling up to a deformation of 300%. As in usual pearlitic structure, its work-hardening shows no saturation and its elongation to fracture remains rather constant instead of decreasing drastically as conventional steels. The hardening by a similitude effect is thus not the privilege of pearlitic steels. Nevertheless, its lower initial work-hardening rate at low strain compared to an equivalent pearlitic steel and a lower hardening potential at high strain let us suspect major differences in the nature and the behaviour of ferrite channels in relation to the morphogenesis of the mic...
Constitutive activation of the oncogenic transcription factor STAT3 frequently occurs in various human malignancies. STAT3 activation involves dimerization via intermolecular pTyr-SH2 interaction. Thus, antagonizing this interaction is a feasible approach to inhibit STAT3 activation for cancer therapy. In order to identify selective STAT3 inhibitors, we developed a biochemical HTS system based on AlphaScreen technology, which measures the abilities of test compounds to antagonize pTyr-SH2 interactions. We screened our chemical libraries using this system and identified 5,15-diphenylporphyrin (5,15-DPP) as a selective STAT3-SH2 antagonist. Selective inhibition of STAT3 nuclear translocation and DNA biding activity was observed in cells treated with 5,15-DPP. IL-6-dependent dimerization of STAT3, c-myc promoter binding and c-myc protein expression were all suppressed by 5,15-DPP, whereas no decrement in either expression or ...
The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. The authors intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions. An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of the literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose ...
A sensitivity analysis was conducted to evaluate the technical issues pertaining to possible destructive interactions between spent nuclear fuels (SNFs) and the stainless steel canisters. When issues are identified through such an analysis, they provide the technical basis for answering what if questions and, if needed, for conducting additional analyses, testing, or other efforts to resolve them in order to base the licensing on solid technical grounds. The analysis reported herein systematically assessed the chemical and physical properties and the potential interactions of the materials that comprise typical US Department of Energy (DOE) SNFs and the stainless steel canisters in which they will be stored, transported, and placed in a geologic repository for final disposition. The primary focus in each step of the analysis was to identify any possible phenomena that could potentially compromise the structural integrity of ...
Abstract Smoke is a mixture of toxic gases and suspended particulate matter of solids and liquids that evolves from a fire of flammable materials. This article presents real-time consequence modeling to track the concentration of individual species in smoke as well as its soot deposition. In the modeling process presented, the burning rate or vapor mass is fed into a combustion model in which the combustion of products has been identified and quantified along with the temperature of the fire. The output of the combustion model is the smoke that will be dispersed into the ambient. The fire geometry, which depends on the type of fire (e.g., pool or flare), is identified. A dispersion model with the capability of determining particulate deposition is then used for tracking the smoke plume. Th...
A graphic approach, terms a Genetic Activity Profile (GAP), was developed to display a matrix of data on the genetic and related effects of selected chemical agents. The profiles provide a visual overview of the quantitative (doses) and qualitative (test results) data for each chemical. Either the lowest effective dose or highest ineffective dose is recorded for each agent and bioassay. Up to 200 different test systems are represented across the GAP. Bioassay systems are organized according to the phylogeny of the test organisms and the end points of genetic activity. The methodology for producing and evaluating genetic activity profile was developed in collaboration with the International Agency for Research on Cancer (IARC). Data on individual chemicals were compiles by IARC and by the US Environmental Protection Agency (EPA). Data are available on 343 compounds selected from volumes 1-53 of the IARC Monographs and on 115 ...
A reasonable understanding of PWR steam generator corrosion mechanisms such as denting and wastage has been developed, and adequate chemistry control programs defined to obviate the magnitude and effects of these modes of attack. However, relatively unique corrosion attack modes have been encountered at several plants notwithstanding the presence of a reasonable to very good chemistry control program when considered in light of the Steam Generator Owners Group chemistry guidelines. The uniqueness of attack also suggests that parameters not routinely measured or monitored may be playing a significant role. In the authors opinions, the only reasonable method of routinely identifying corrosion accelerating species present in crevices, sludge piles, and deposits in PWR steam generators is by performing detailed chemical return studies during power transients, shutdowns, and long term layups. Although it would be preferable to obtain samples from ...
Lead is contained as trace element in uranium ores and propagates throughout the production process to intermediate products like yellow cake or uranium oxide. The lead isotopes in such material originate from two sources: natural lead and radiogenic lead. The variability of the isotopic composition of lead in ores and yellow cakes was studied and the applicability of this parameter for nuclear forensic investigations was investigated. Furthermore, the chemical impurities contained in these materials were measured in order to identify characteristic differences between materials from different mines. For the samples investigated, it could be shown, that the lead isotopic composition varies largely from mine to mine and it may be used as one of the parameters to distinguish between materials of different origins. Some of the chemical impurities show a similar pattern and support the conclusions drawn from the lead isotope ...
Abstract The Eiffel Tower edifice is situated in the Lucky Strike hydrothermal vent field at a mean depth of 1690-m on the Mid-Atlantic Ridge (MAR). At this 11-m-high hydrothermal structure, different faunal assemblages, varying in visibly dominant species (mussels and shrimp), in mussel size and in density of mussel coverage, were sampled biologically and chemically. Temperature and sulphide (-S) were measured on the different types of mussel-based assemblages and on a shrimp-dominated assemblage. Temperature was used as a proxy for calculating total concentrations of CH4. Based on the physico-chemical measurements, two microhabitats were identified, corresponding to (i) a more variable habitat featuring the greatest fluctuations in environmental variables and (ii) a second, more stable, ...
A compact and supersensitive device that can rapidly detect minute trace vapors from concealed explosives has been developed by scientists at Oak Ridge National Laboratory (ORNL). The new explosives sensor can detect and chemicallyidentify organic nitrogen-oxygen compounds which are the building blocks of explosives such as TNT, plastiques, and nitroglycerine. The device could be used to scan persons entering airport terminals, nuclear power plants, defense installations, or other sensitive locations, providing greater security against potential terrorism. This device works on a glow discharge principle, and is more specifically called an ''Atmospheric Sampling Glow Discharge Ionization'' (ASGDI) source. The new detector is a highly automated, miniaturized version of research mass spectrometers widely used to trace constituents of chemical mixtures. Detail of this device's ...
Part 1 of the Electric Utility Engineer`s Flue Gas Desulfurization (FGD) Manual emphasizes the chemical and physical processes that form the basis for design and operation of lime- and limestone-based FGD systems applied to coal- or oil-fired steam electric generating stations. The objectives of Part 1 are: to provide a description of the chemical and physical design basis for lime- and limestone-based wet FGD systems; to identify and discuss the various process design parameters and process options that must be considered in developing a specification for a new FGD system; and to provide utility engineers with process knowledge useful for operating and optimizing a lime- or limestone-based wet FGD system.
The paper describes the chemical constituents isolated from aerial parts of the plant Galianthe brasiliensis. From a methanol extract, the iridoid glycosides asperuloside, deacetylasperuloside, mixture of Z- and E-6-O-p-coumaroylscandoside methyl ester, the triterpene ursolic acid and the steroids stigmasterol, campesterol, b-sitosterol and 3-O-b-glucopyranosyl sitosterol were isolated. The structures of the natural products were identified on the basis of spectral data, including 2D NMR experiments. The antiproliferative properties of the crude methanolic extract were investigated against a series of nine human cancer cell lines. (author)
Carbon capture and storage have been receiving increasing interest lately, mainly as an option to reduce CO{sub 2} emissions from the power sector. The concept could be adapted for production of H{sub 2} as well, which would provide a carbon free energy carrier that could be used for example as transportation fuel. In this doctoral thesis, the option to use chemical-looping technologies to produce H{sub 2} from fossil fuels with CO{sub 2} capture is explored. In chemical-looping combustion, direct contact between fuel and combustion air is avoided. Instead, a solid oxygen carrier performs the task of bringing oxygen from the air to the fuel. Thus, the resulting CO{sub 2} and H{sub 2}O are not diluted with N{sub 2}, and pure CO{sub 2} can easily be recovered by cooling and condensation. The heat of reaction is the same as for ordinary combustion. Chemical-looping reforming uses the same basic principles as ...
Double-crystal high-resolution x-ray fluorescence spectrometry was applied to the state analysis of sulfur in coal and related fly ash. For total sulfur, a proportional relationship exists between fluorescence intensities and the analytical values obtained by the oxygen-combustion method. Two oxidation states of sulfur were identified by a least square curve fitting method, by assuming that the spectrum profile is identical for each sulfur state but the intensity and position are different. The chemical state of sulfur in coal and remaining in fly ash is discussed.
An acute fish toxicity model was constructed on the basis of a wide series of experimental data for guppy. The Multiple Computer-Automated structure Evaluation program was used to construct the model. The created model possesses very good predictive ability. It can correctly predict acute toxicity for guppy for 80% of compounds with an average error of only 0.63 log unit per median lethal concentration. The importance of the narcosis effect was demonstrated. The main toxicophores, corresponding to polar narcosis and to the reactive chemicals, were identified.
The objectives of the project were to develop operational techniques for promoting contaminant hideout return from tube support crevices and to identify the effect of chemical inhibitor application on corrodent transport. The implementation of routine procedures for promoting the return of sequestered corrodents could retard the progression of denting or other corrosion processes and improve steam generator availability. Tests also quantified the effect of inhibitor application on crevice hideout and hideout return processes, with the intention of developing a better understanding of the inhibition mechanism. By carefully monitoring the hideout and hideout return inventories, the program also has provided the opportunity to study steam generator concentration processes in general.
A series of short articles discusses: use of a chemically bonded ceramic composite liner, WellerDensit, to protect the steel surface of pulverizer classifier cones; use of a fused cast basalt liners developed by Abresist Corp. in pipes for transporting coal and ash; a survey completed by the National Energy Technology Laboratory to identify causes of outages and other concerns expressed by PC and FBC boiler operators; and Temp-Age, Early Visc-Age and Modern Visc-Age systems for controlling the viscosity of heavy fuel oil to maintain proper combustion. 7 figs.
New studies are always needed to better determine the physico-chemical processes involved in the combustion of natural gas. The understanding of the reaction mechanisms that lead to the formation of nitrogen oxides or volatile organic compounds requires to identify the inner mechanisms which take place during combustion and in particular the mechanisms of formation of intermediate products. The aim of this study is to analyze the thermal degradation of methane and ethane in low pressure pre-mixed stabilized laminar flames condition, because both of these compounds represent the major part of natural gas composition. The main chemical reaction ways identified in the studied flames and responsible for combustion have been identified after a comparison between experimental results and the computerized simulation performed using an a-priori postulated chemical ...
Environmental research related to uranium tailings is being carried out within the Mining Research Laboratories and Mineral Sciences Laboratories of CANMET, EMR. Field-related research on uranium tailings has been conducted at Elliot Lake for over five years. Much of the work has been focused on a program to rehabilitate pyritic tailings. This has resulted in developing a practicable technology for growing vegetation on such wastes. Limitations have been small size of the test-plots and the relatively short period during which experiments have been carried out. A research program aimed at identifying and reducing acidic and radioactive effluents is also underway at Elliot Lake. These liquid effluents have been identified as the most serious threat to the environment. Research at the Mineral Sciences Laboratories and its predecessor divisions relating to the processing of uranium and thorium ores is outlined. A process has been developed for ...
Genomic instability can be produced by ionising radiation, so-called radiation-induced genomic instability, and chemical mutagens. Radiation-induced genomic instability occurs in both germinal and somatic cells and also in the offspring of irradiated individuals, and it is characterised by genetic changes including chromosomal rearrangements. The majority of studies of trans-generational, radiation-induced genomic instability have been described in the male germ line, whereas the authors who have chosen the female as a model are scarce. The aim of this work is to find out the radiation-induced effects in the foetal offspring of X-ray-treated female rats and, at the same time, the possible impact of this radiation-induced genomic instability on the action of a chemical mutagen. In order to achieve both goals, the quantity and quality of chromosomal damage were analysed. In order to detect trans-generational genomic instability, a total of 4806 ...
The US Department of Energy (DOE) is responsible for cleanup activities at the Weldon Spring site in St. Charles County, Missouri. The site consists of a chemical plant area and a noncontiguous limestone quarry; both areas are radioactively and chemically contaminated as a result of past processing and disposal activities. Explosives were produced by the US Army at the chemical plant in the 1940s, and uranium and thorium materials were processed by DOE`s predecessor agency in the 1950s and 1960s. During that time, various wastes were disposed of at both areas of the site. The DOE is conducting cleanup activities at the site under its Environmental Restoration and Waste Management Program. The integrated remedial investigation/feasibility study-environmental impact statement (RI/FS-EIS) documents for the chemical plant area were issued to the public in November 1992 as the draft RI/FS-EIS. (The CERCLA ...
Material related to routine as well as sensitive aspects of parent/day care center relationships is presented in this training module, one of a series providing staff development information for programs operated for dependents of military personnel. The module offers a brief discussion of ways caregivers can help parents feel at ease about leaving their children in child care and presents a set of multiple-choice skill-building exercises for effectively working with parents. Exercises focus on various topics, including how parents can be approached when their child may have a health problem, when child abuse or neglect is suspected, and when parental cooperation is needed to stop a child's undesirable or disruptive behavior. Exercises are also devoted to the questions of whether or not caregivers should act as advisors to parents or tell parents about their child's behavior at the center. Concluding exercises indicate how caregivers can handle parent requests for ...
Combined energy plants operating on the Brayton-Rankine cycle have gained wide acceptance as the most efficient energy conversion system. The technology is well proven and numerous research activities are underway to develop it further past its present plateau of performance. In developed and emerging economies alike, the current situation in the global economic market has caused the liberalisation of the energy industry in some countries, and in others it is causing a rethink of economic and energy policies. A result is that electric utility companies that have enjoyed a monopoly in power generation and distribution are seeing this privilege being eroded. This is opening up opportunities for independent power production and, consequently, for gas/steam turbine plants because of the technical merits of the technology and its ability to fill the vacuum being created in the energy industry. An economic model has been developed for carrying out life cycle costs ...
Solid state nuclear track detectors (SSNTD) record radiation in the form of tracks. In the case of high track density, however, it is not always possible to distinguish each track separately. The track density might then be underestimated unless the loss of track number due to overlapping is compensated. An elaborated 'erosion' or curve fitting process is applied usually, for the separation of the overlapping tracks, to automatic track counting systems. This paper shows a much simpler correction method which was developed by the analogy of the correction equation for the dead time of GM counters. From a set of about 10 data obtained from high track density detectors, the equation for SSNTD can be determined by a least square fitting. Once the equation is found, true track density could be derived easily without any help of complex image processing or calculation, such as the erosion or curve fitting. This method also provides the privilege of ...
A recently developed neutron diagnostic probe system has the potential to satisfy a significant number of van-mobile and fixed- portal requirements for nondestructive verification of sealed munitions and detection of contraband explosives and drugs. The probe is based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons generated from the deuterium-tritium reaction and that detects the alpha-particle associated with each neutron. Gamma-ray spectra of resulting neutron inelastic scattering and fission reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. Flight times determined from determined from detection times of the gamma-rays and alpha-particles yield a separate tomographic image ...
Chemical phase identifications of complex, multilayered corrosion products formed on Fe-Ni-Cr alloys immersed in molten NaNO/sub 3/-KNO/sub 3/ and LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/ were obtained by X-ray diffraction analysis. Diffraction analyses performed after successive material removal steps provided depth profiles of corrosion products and identified the dominant phases as NaFeO/sub 2/, Fe/sub 3/O/sub 4/, and Cr/sub 2/O/sub 3/ for Alloy 800 and 316SS after immersion in NaNO/sub 3/-KNO/sub 3/. In LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/, the major corrosion products identified on Alloy 800 were LiFeO/sub 2/, Fe/sub 3/O/sub 4/, and Cr/sub 2/O/sub 3/. X-ray diffraction results were supplemented by electron microprobe analyses that revealed the solid solution nature of several of the oxide phases.
This report presented an analysis of incidents gathered by the Canadian upstream oil and gas industry committee in relation to explosive atmospheres in wellbores, vessels, tanks, and piping systems. The aim of the report was to develop industry recommended practices for oil and gas industry fires and explosions. Two accident theory models were used to set out the relationships between hazards, defenses, and losses. Three levels of defenses were identified based on organizational, local workplace, and human factors. An organizational responsibility approach was used to examine the activities of key people with the system. Incidents were analyzed based on an expanded fire triangle used to identify fire and explosion hazards. The study showed that the ignition of hydrocarbons into the air was a factor in nearly 50 per cent of the incidents. A lack of understanding of liquid-hydrocarbon properties was demonstrated in incidents involving oxidized ...
This report describes the work performed during FY 1995 by Pacific Northwest Laboratory in developing and optimizing analysis techniques for identifying organics present in Hanford waste tanks. The main focus was to provide a means for rapidly obtaining the most useful information concerning the organics present in tank waste, with minimal sample handling and with minimal waste generation. One major focus has been to optimize analytical methods for organic speciation. Select methods, such as atmospheric pressure chemical ionization mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry, were developed to increase the speciation capabilities, while minimizing sample handling. A capillary electrophoresis method was developed to improve separation capabilities while minimizing additional waste generation. In addition, considerable emphasis has been placed on developing a rapid screening tool, based on Raman and ...
Gas-insulated systems employing SF/sub 6/ are utilized in a variety of applications in power delivery systems. Because electric arcs, sparks or corona can decompose SF/sub 6/ into by-products having chemical properties different from SF/sub 6/, environmental concerns arise regarding inadvertent human exposures to electrically-decomposed SF/sub 6/. Biological assays in our laboratory using mammalian cell culture systems have revealed that SF/sub 6/, spark-decomposed under specific experimental conditions, can produce cell death. Chemical analysis of spark-decomposed SF/sub 6/ has identified the major decomposition pathways and by-products. Biological testing of individual by-products or by-product mixtures has indicated that these major decomposition products may not account for the majority of the cell killing effects seen in our assays. Further experiments have suggested that S/sub 2/F/sub 10/ may be produced and ...
The authors have discovered chert xenoliths from green rocks in the Pippu area, central Hokkaido, Japan. Reports were given on the discovery with regard to the state of its production, chemical composition of the green rocks, and radiolarian fossils produced from the chert and their age. Considerations were given on the geological significance thereof. On 23 green rocks and five cherts out of the collected samples, rock slices were prepared, and petrographic statement was made by using a polarizing microscope. In addition, the whole petro-chemical composition analysis was performed on green rocks to discuss the radiolarian fossils and geological ages. The following conclusions were obtained as a result: green rocks may be identified as a product of igneous activities in a large plate in a certain period from the latter Callovian period of the middle age of the Jurassic period to the Barremian period of the Paleozoic era in ...
Olive bagasse (Olea europea L.) was pyrolysed in a fixed-bed reactor. The effects of pyrolysis temperature, heating rate, particle size and sweep gas flow rates on the yields of the products were investigated. Pyrolysis runs were performed using pyrolysis temperatures between 350 and 550 {sup o}C with heating rates of 10 and 50 {sup o}C min{sup -} {sup 1}. The particle size and sweep gas flow rate varied in the ranges 0.224-1.8 mm and 50-200 cm{sup 3} min {sup -1}, respectively. The bio-oil obtained at 500 {sup o}C was analysed and at this temperature the liquid product yield was the maximum. The various characteristics of bio-oil obtained under these conditions were identified on the basis of standard test methods. The empirical formula of the bio-oil with heating value of 31.8 MJ kg{sup -1} was established as CH{sub 1.65}O{sub 0.25}N{sub 0.03}. The chemical characterization showed that the bio-oil obtained from olive bagasse may be ...
Many assays for oncogenic transformation have been developed ranging from those in established rodent cell lines where morphological alteration is scored, to those in human cells growing in nude mice where tumor invasiveness is scored. In general, systems that are most quantitaive are also the least relevant in terms of human carcinogenesis and human risk estimation. The development of cell culture systems has made it possible to assess at the cellular level the oncogenic potential of a variety of chemical, physical and viral agents. Cell culture systems afford the opportunity to identify factors and conditions that may prevent or enhance cellular transformation by radiation and chemicals. Permissive and protective factors in radiation-induced transformation include thyroid hormone and the tumor promoter TPA that increase the transformation incidence for a given dose of radiation, and retinoids, selenium, vitamin E, and ...
Many assays for oncogenic transformation have been developed ranging from those in established rodent cell lines where morphological alteration is scored, to those in human cells growing in nude mice where tumor invasiveness is scored. In general, systems that are most quantitaive are also the least relevant in terms of human carcinogenesis and human risk estimation. The development of cell culture systems has made it possible to assess at the cellular level the oncogenic potential of a variety of chemical, physical and viral agents. Cell culture systems afford the opportunity to identify factors and conditions that may prevent or enhance cellular transformation by radiation and chemicals. Permissive and protective factors in radiation-induced transformation include thyroid hormone and the tumor promoter TPA that increase the transformation incidence for a given dose of radiation, and retinoids, selenium, vitamin E, and ...
PWR steam generators have suffered from a variety of degradation phenomena. This paper identifies the corrosion-related defects and their probable causes and suggests approaches to correct and prevent corrosive activity. In the attempt to solve the degradation problems, research programs have concentrated on modifying materials, stresses, and the chemical environment in both new and operating steam generators. The following corrosion-related defects have been studied: tube wastage, denting, primary side (ID) intergranular stress corrosion cracking (IGSCC), OD-initiated intergranular attack (IGA), pitting, and corrosion fatigue. Plants affected by wastage have greatly reduced their problem by adopting an all volatile treatment (AVT). In the case of denting, a less aggressive chemical environment is recommended. Primary side IGSCC responds to temperature reduction, stress relief, and material improvements, while flushing and ...
PWR steam generators have suffered from a variety of degradation phenomena. This paper identifies the corrosion-related defects and their probable causes and suggests approaches to correct and prevent corrosive activity. In the attempt to solve the degradation problems, research programs have concentrated on modifying materials, stresses, and the chemical environment in both new and operating steam generators. The following corrosion-related defects have been studied: tube wastage, denting, primary side (ID) intergranular stress corrosion cracking (IGSCC), OD-initiated intergranular attack (IGA), pitting, and corrosion fatigue. Plants affected by wastage have greatly reduced their problem by adopting an all volatile treatment (AVT). In the case of denting, a less aggressive chemical environment is recommended. Primary side IGSCC responds to temperature reduction, stress relief, and material improvements, while flushing and ...
Indicators are important tools for communicating and making accessible scientific and technical information to policymakers and the general public. They therefore play an important role in transforming information into action. Worldwide, many initiatives are underway to construct indicators for a variety of purposes, including those for reporting on sustainable development. This paper briefly describes the attempts made so far, but stresses that the users of the indicators should play a greater role in indicator construction. In developing countries, a substantial lack of data has meant that specific policy formulation may develop without adequate technical input. In developed countries also, data gaps may hinder policy formulation, implementation, and evaluation. However, the development of indicators as tools to assist in the management of hazardous wastes and toxic chemicals is still in the early stages of formulation. A more imaginative program of indicators ...
A method for quick, high-accuracy measurement of lithium isotopes has become necessary in carrying out research on the separation and concentration of lithium isotopes by ion exchange. The present report focuses on the application of a hollow cathode, as excitation source, to emission spectral analysis for lithium isotope measurement. The grating monochromator used incorporates a pressure scanned etalon. With decreased Doppler broadening and pressure broadening, the hollow cathode, used as excitation source, can give narrow spectral lines, permitting good separation among them. To achieve a high accuracy, the emission intensity of the hollow cathode should be maintained as stable as possible relative to time. In particular, the stability of a light source can be affected significantly by the chemical form of the sample. A study is also made here to identify a condition where lithium acetate effluent as-obtained from an ion exchange column can ...
An analysis was made on corrosion suppression mechanism of glycoletherdiaminetetraacetic acid (GEDTA) film made from GEDTA on stainless steel, and its corrosion inhibition effect. Results of analysis using IR spectrum, IR-ATR spectrum, {sup 1} HNMR spectrum, and ESCA spectrum indicated the deposition of the GEDTA film is a chemical deposition. In polarization tests at pH = 5 and 7, both polarization curves shifted to the constant current density side, showing suppression effect in reactions at both pH. When the corrosion environment is made severer, such as to pH = 2 and 4, the corrosion suppression effect of GEDTA became more distinctive. A ferroxyl test identified very little difference between untreated and treated materials. In a chemical pitting test, because oxidant and corrosive anion coexist in the test solution, and GEDTA is stable against corrosive anion Cl {sup {minus}}, the film is unstable against the oxidant. ...
Managing sites contaminated with munitions constituents is an international challenge. Although the choice of approach and the use of Ecological Risk Assessment (ERA) tools may vary from country to country, the assurance of quality and the direction of ecotoxicological research are universally recognized as shared concerns. Drawing on a multidisciplinary team of contributors, 'Ecotoxicology of Explosives' provides comprehensive and critical reviews available to date on fate, transport, and effects of explosives. The book delineates the state of the science of the ecotoxicology of explosives, past, present, and recently developed. It reviews the accessible fate and ecotoxicological data for energetic materials (EMs) and the methods for their development. The chapters characterize the fate of explosives in the environment, then provide information on their ecological effects in key environmental media, including aquatic, sedimentary, and terrestrial habitats. The book ...
The fundamental mechanisms underlying the chemical degradation of polymers can change as a function of environmental stress level. When this occurs, it greatly complicates any attempt to use accelerated tests for predicting long-term material degradation behaviors. Understanding how degradation mechanisms can change at different stress levels facilitates both the design and the interpretation of aging tests. Oxidative degradation is a predominant mechanism for many polymers exposed to a variety of different environments in the presence of air, and there are two mechanistic considerations which are widely applicable to material oxidation. One involves a physical process, oxygen diffusion, as a rate-limiting step. This mechanism can predominate at high stress levels. The second is a chemical process, the time-dependent decomposition of peroxide species. This leads to chain branching and can become a rate-controlling factor at lower stress levels ...
The Hanford Site, Richland, Washington, contains over 1,500 identified waste sites and numerous groundwater plumes that will be characterized and remediated over the next 30 years. As a result of the Hanford Federal Facility Agreement and Consent Order, the US Department of Energy (DOE) has initiated a remedial investigation/feasibility study (RI/FS) at the 200-BP-1 operable unit. The 200-BP-1 RI/FS is the first Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) investigation on the Hanford Site that involves highly radioactive and chemically contaminated soils. The initial phase of site characterization was designed to assess the nature and extent of contamination associated with the source waste sites within the 200-BP-1 operable unit. Characterization activities consisted of drilling and sampling, chemical and physical analysis of samples, and development of a conceptual vadose zone model. ...
Simple, one-zone models for inhomogeneous chemical evolution of the Galactic halo are used to predict the number fraction of zero-metallicity, Population III stars, which currently is empirically estimated at < 4e-4. These analytic models minimize the number of free parameters, highlighting the most fundamental constraints on halo evolution. There are disagreements of at least an order of magnitude between observations and predictions in limiting cases for both homogeneous Simple Model and Simple Inhomogeneous Model (SIM). Hence, this demonstrates a quantitative, unambiguous discrepancy in the observed and expected fraction of Population III stars. We explore how the metallicity distribution of the parent enrichment events f(z_0) drives the SIM and predictions for the Population III fraction. The SIM shows that the previously-identified "high halo" and "low halo" populations are consistent with a continuous evolutionary progression, and ...
The non-isothermal pyrolysis kinetics of Acetocell (the organosolv) and Lignoboost (kraft) lignins, in an inert atmosphere, have been studied by thermogravimetric analysis. Using isoconversional analysis, it was concluded that the apparent activation energy for all lignins strongly depends on conversion, showing that the pyrolysis of lignins is not a single chemical process. It was identified that the pyrolysis process of Acetocell and Lignoboost lignin takes place over three reaction steps, which was confirmed by appearance of the corresponding isokinetic relationships (IKR). It was found that major pyrolysis stage of both lignins is characterized by stilbene pyrolysis reactions, which were subsequently followed by decomposition reactions of products derived from the stilbene pyrolytic pr...
Diet overlap and niche breadth are well-known species traits from trophic ecology that can assist in explaining how species interact and coexist as well as the ecological mechanisms that influence biodiversity. In the present study, we analyzed the relationships between these trophic variables and indicators of resource availability with some attributes of fish assemblages (species richness, Shannon diversity index, evenness, density and individual body size). The physical and chemical characteristics of the biotopes (topography, water quality and conservation of slopes) were examined to identify possible patterns. Monthly sampling using electrofishing was conducted in 2003 along five streams located in the Cuiab? River watershed. The relationships between environmental variables and attri...
The aim of our research was to identify structures and chemical compositions of phases formed during internal oxidation of multi-component Ag-Zn-Mg-based alloys. Since the ability of inoculation mostly depends on large free energy of formation of oxides of microalloying elements and their crystallographic similarity, Mg in quantities of 0.001-0.5 mass% was selected as a micro-alloying element. These correspond to the quantities of 0.005-2.5 vol.% of MgO in the selected Ag-Zn-based alloys. Ag-based metal matrix, heterogeneous nuclei of MgO and oxide (ZnO) of the main alloying element were analysed by transmission electron microscopy (TEM). Structural inter-connections among them were also investigated and analysed. In situ phenomenon of heterogeneous nucleation of MgO and ZnO was proved. (orig.)
The condensation reaction of furfural (F) on acetone (Ac) gives a high added value product, the 4-(2-furyl)-3-buten-2-one (FAc), used as aroma in alcohol free drinks, ice, candies, gelatines and other products of current life. This synthesis valorises the residues of sugar cane treatment since furfural is obtained by hydrolysis of sugar cane bagasse followed by vapor training extraction. In the face of numerous and complex reactions involved in this synthesis, it is very complicated to define the kinetic laws from exact stoichiometry. A solution allowing to cope the problem consists in identifying an appropriate stoichiometric model. It does not attempt to represent exactly all the reaction mechanisms, but proposes a mathematical support to integrate available knowledge on the transformati...
Presented are the results from a laboratory test program conducted to identify and evaluate materials for converting hazardous geothermal residues to a non-hazardous and potentially usable form. Results indicate that the residues can be effectively incorporated, as a fine aggregate, into portland cement-based composites. Five geothermal residues obtained from sites in the Salton Sea area of California were evaluated. Three of these were classified as hazardous. After mixing with cement, the leach rates were all well below specified levels. Although structural-grade composites were produced, gradual reductions in properties with time up to 1 yr were noted. This indicates ongoing chemical reactions between the cement paste and the constituents of the residues. Further research is necessary before the composites could be considered for use in structural applications. 3 refs., 8 tabs.
Soluble starch?based biodegradable and microporous microspheres (SDM-Ms) were prepared by emulsion chemical cross-linking technique using trisodium trimetaphosphate (TSTP) as the cross-linker. The resultant amorphous SDM-Ms were excellently identified by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The internal rupture and surface-controlled erosion were the predominant degradation mechanisms for SDM-Ms. The obtained SDM-Ms were applied to adsorb coix seed oil (CSO) by immersing method. The adsorption capacity of CSO within SDM-Ms was determined, namely 0.5238?g/g, and the thermal stability was shown higher than that of the free CSO. A burst release appeared in the second hour, followed by controlled release. Diffusion, d...
The steam generator availability is one of the important problems encountered during the pressurized water nuclear plant operation. Various kinds of corrosion phenomena were observed in the past. These phenomena result from the concentration of impurities mainly in three locations in the steam generators: the tubesheet crevices, the tube support plate crevices, and the sludge pile. Corrections were made in the design and the materials used but a number of steam generators suffer or will suffer from corrosion processes inducing in many cases forcing their replacement. In order to prevent or to retard the corrosions several laboratories have performed experiments to reproduce and to study the corrosion processes. The first step of the degradation is the concentration of chemical species. A method using /sup 24/Na as a radioactive tracer was used to establish the concentration kinetics of caustic which was identified as the major cause of the ...
The scope of this RA is limited to the evaluation of potential human health risks associated with a failure event of a tank containing Basin F liquid. Section 1.0 contains an introduction to the health risk assessment. Section 2.0 describes the site history, location, and land use. Section 3.0 provides a brief description of exposure pathways and potention receptors. Section 4.0 describes the sources of data used and identifieschemicals of concern. Section 5.0 discusses the toxicity of concern. Section 6.0 explains the methods used for calculation of carcinogenic risks and the noncarcinogenic hazard indexes. Section 7.0 describes uncertainties inherent in the current methodology used to determine potential human health risks. Section 8.0 presents a summary of results and conclusions. Section 9.0 includes the references cited.
Nowadays, mixing is one of the most powerful tools for the process and products optimization in chemical process industries. The available technology can help in achieving almost any desired outcomes related to the process-side of the systems. This paper presents a practical methodology to improve existing agitation systems in order to overcome the constraints previously identified in the process. Well succeed real cases using this methodology in a petrochemical plant (Nitriflex S.A.) are presented. (author) 13 refs., 1 figs., 2 tabs.
To our knowledge, the fluorescence studies of lanthanides in LiCl-KCl eutectic molten salt at a high temperature are not reported yet. The fluorescence of the lanthanide-ions was generally decreased when the temperature was increased. Moreover, the fluorescence of the lanthanides was strong when the sample was solidified to or from the melt. The temperature, where the fluorescence was decreased, was identified to be different depending on the species of the lanthanides and the substrates was considered to possibly be from quenching of the fluorescence due to either the collisions of melted samples induced by high temperature media or the re-absorption of fluorescence by the samples. Several comparison experiments were performed to explain and understand this phenomenon and improve the fluorescence. In this way, an on-line monitoring of chemical species and the concentration for lanthanides elements in molten salt media of pyrochemical process ...
Nuclear approaches for compositional characterization has bright application prospect in forensic perspective towards assessment of nature and origin of seized material. The macro and micro physical properties of nuclear materials can be specifically associated with a process or type of nuclear activity. Under the jurisdiction of nuclear analytical chemistry as well as nuclear forensics, thrust areas of scientific endeavor like determination of radioisotopes, isotopic and mass ratios, analysis for impurity contents, arriving at chemical forms/species and physical parameters play supporting evidence in forensic investigations. The analytical methods developed for this purposes can be used in international safeguards as well for nuclear forensics. Nuclear material seized in nuclear trafficking can be identified and a profile of the nuclear material can be created
Community ecologists are principally occupied with the proposition that natural assemblages of species exhibit orderliness and with identifying its causes. Plant-pollinator networks exhibit a variety of orderly properties, one of which is 'nestedness'. Nestedness has been attributed to various causes, but we propose a further influence arising from the phylogenetic structure of the biochemical constraints on the pollen diets of bees. We use an artificial assemblage as an opportunity to isolate the action of this mechanism. The properties of the network that we studied are consistent with the proposition that nestedness is caused by the phylogeny of diet range in bees, but the claim is preliminary and we propose that valuable progress in understanding plant-pollinator systems may be made through applying the techniques of chemical ecology at the community scale.
The effect of sugar on plant metabolism, which is known to be similar to hormone-like signaling, was metabolomically studied using Melissa officinalis (lemon balm). The metabolite profiles of M. officinalis treated with sucrose were analyzed by gas chromatography-mass spectrometry (GC-MS) and principal component analysis (PCA). A total of 64 metabolites from various chemical classes including alcohols, amines, amino acids, fatty acids, inorganic acids, organic acids, phosphates, and sugars were identified by GC-MS. Three groups treated with different sucrose concentrations were clearly separated by PCA of their metabolite profiles, indicating changes in the levels of many metabolites depending on the sucrose concentration. Metabolite profiling revealed that treatment with a higher sucrose ...
Sulfur mustard (HD) is an alkylating and cytotoxic chemical warfare agent, which inflicts severe skin toxicity and an inflammatory response. Effective medical countermeasures against HD-caused skin toxicity are lacking due to limited knowledge of related mechanisms, which is mainly attributed to the requirement of more applicable and efficient animal skin toxicity models. Using a less toxic analog of HD, chloroethyl ethyl sulfide (CEES), we identified quantifiable inflammatory biomarkers of CEES-induced skin injury in dose- (0.05-2 mg) and time- (3-168 h) response experiments, and developed a CEES-induced skin toxicity SKH-1 hairless mouse model. Topical CEES treatment at high doses caused a significant dose-dependent increase in skin bi-fold thickness indicating edema. Histopathological e...
This report discusses the development and demonstration of innovative combustion technologies that improve energy conservation and environmental practices in the US industrial sector. The report includes recommendations by industry on R&D needed to resolve current combustion-related problems. Both fundamental and applied R&D needs are presented. The report assesses combustion needs and suggests research ideas for seven major industries, which consume about 78% of all energy used by industry. Included are the glass, pulp and paper, refinery, steel, metal casting, chemicals, and aluminum industries. Information has been collected from manufacturers, industrial operators, trade organizations, and various funding organizations and has been supplemented with expertise at the Idaho National Engineering Laboratory to develop a list of suggested research and development needed for each of the seven industries.
We study dipolar bosons in a 1D optical lattice and identify a region in parameter space---strong coupling but relatively weak on-site repulsion---hosting a series of stable CDW states whose low-energy excitations, built from "fractional domain walls", are remarkably similar to those of non-abelian fractional quantum Hall states. Here, a conventional domain wall between translated CDW's may split by inserting strings of degenerate, but inequivalent, CDW states. Outside these insulating regions, we find numerous supersolids as well as a superfluid regime. The mentioned phases should be accessible experimentally, and in particular, the fractional domain walls can be created in the ground state using single-site addressing, i.e. by locally changing the chemical potential.
One of the technical options being considered for long term disposition of weapons grade plutonium is geologic storage at Yucca Mountain. Multikilogram quantities of plutonium are to be vitrified, placed within a heavy steel container, and buried in the material know as Nevada tuff. It has been postulated that after ten thousand years, geologic and chemical processes would have disintegrated the steel container and created the possibility for plutonium to form mixtures with Nevada tuff and water that could lead to a nuclear explosion in the range of kilotons. A survey and description of critical homogeneous mixtures of plutonium, silicon dioxide, Nevada tuff, and water which also identified the mixture regimes where autocatalytic dynamic behavior is possible was completed. This study is a follow up of this survey and the major objective is to examine the dynamic behavior of the worst case critical and supercritical configurations of plutonium, ...
The objective of this project is to develop multi-dimensional computational models in order to improve the operation of uranium electrorefiners currently used in pyroprocessing technology. These 2-D (US) and 3-D (ROK) mathematical models are based on the fundamental physical and chemical properties of the electrorefiner processes. The validated models by compiled and evaluated experimental data could provide better information for developing advanced electrorefiners for uranium recovery. The research results in this period are as follows: - Successfully assessed a common computational platform for the modeling work and identify spatial characterization requirements. - Successfully developed a 3-D electro-fluid dynamic electrorefiner model. - Successfully validated and benchmarked the two multi-dimensional models with compiled experimental data sets
Evaluating the need for remedial cleanup at a waste site involves both finding the average contaminant concentration and identifying highly contaminated areas, or hot spots. A nomographic procedure to determine the sample configuration needed to locate a hot spot is presented. The technique can be used to develop a waste-site sampling plant - to determine either the grid spacing required to detect a hot spot at a given level of confidence, or the probability of finding a hot spot of a certain size, given a particular grid spacing. The method and computer program (ELIPGRID) were developed for locating geologic deposits, but the basic procedure can also be used to detect hot spots at chemical- or nuclear-waste disposal sites. Nomographs based on the original program are presented for three sampling-grid configurations - square, rectangular and triangular.
This paper summarizes an investigation carried out on Polish terrain occupied by Russian Federation military troops. The investigation identified natural environmental devastation, pollution, and contamination. Quantitative estimation of the devastation and its economic evaluation are provided. The results of the investigation are as follows: 406 ha have been contaminated by petrochemical products; 22.7 ha are chemically polluted; and 6,500 ha of underground water, as well as 17.5 ha of surface water, cannot be classified. On 15,300 ha the soil has been degraded, of which landfills comprise an area of 98 ha. No toxic warfare agents have been detected, nor any radioactivity levels exceeding those characteristic of the given region.
Recent advances made in the area of amorphous and nanocrystalline alloys exhibiting high saturation inductions are reviewed. A new chemical composition was identified that achieves a saturation induction of 1.64 T in an iron-based amorphous alloy. This alloy, when used in electrical transformers, shows a much improved performance over the existing amorphous alloy. Nanocrystalline FeCoCuNbSiB alloys are found to have saturation induction levels reaching 1.7 T. These materials are suited for use in sensors and inductors carrying large currents. Some of these nanocrystalline alloys show a BH squareness ratio exceeding 90%, which can be utilized in pulse power devices. Recent developments in the applications of these materials are also pointed out.
The primary function of the Waste Handling Shaft (WHS) at the Waste Isolation Pilot Plant (WIPP) is to permit the transfer of radioactive waste from the surface waste handling building to the underground storage area. It also serves as an intake shaft for small volumes of air during normal storage operations and as an emergency escape route. Part of the construction was the placement of a concrete liner and steel reinforced key in 1984. During a routine shaft inspection in May 1990, some degradation of the WHS concrete liner was observed between the depths of 800 and 900 feet below the ground surface. Detailed investigations of the liner had been carried out by Sandia National Laboratories and by Westinghouse Electric Corporation Waste Isolation Division (WID) through Lankard Materials Laboratory. Observations, reports, and data support the conclusion that the concrete degradation, resulting from attack by chemically aggressive brine, is a localized phenomena. It ...
Formaldehyde, a well-identified indoor pollutant, was recently classified as carcinogenic. New regulations for the air quality are expected and therefore there is a need for low-cost sensors, sensitive and selective with a fast response time for the detection of formaldehyde at ppb level. In the present work, we had developed a chemical sensor based on nano-porous matrices doped with Fluoral-P and optical methods of detection. The nano-porous matrices, elaborated via the Sol-Gel process, display nano-pores whose cavity is tailored for the trapping of the targeted pollutant. They provide a first selectivity with the discrimination of the pollutants by their size. A second selectivity is obtained with a molecular probe, Fluoral-P, which reacts specifically with formaldehyde leading to the 3,5- di-acetyl-1,4-dihydro-lutidine (DDL). The kinetics of formation of DDL was studied as function of many parameters such as the concentration of Fluoral-P in ...
The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable ...
The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable ...
A large part of mechanical and durability characteristics of cement-based materials comes from the performances of the hydrated cement, cohesive matrix surrounding the granular skeleton. Experimental studies, in situ or in laboratory, associated to models, have notably enhanced knowledge on the cement material and led to adapted formulations to specific applications or particularly aggressive environments. Nevertheless, these models, developed for precise cases, do not permit to specifically conclude for other experimental conclusions. To extend its applicability domain, we propose a new evolutive approach, based on reactive transport expressed at the microstructure scale of the cement. In a general point of view, the evolution of the solid compounds of the cement matrix, by dissolutions or precipitations, during chemical aggressions can be related to the pore solution evolution, and this one relied to the ionic exchanges with the external environment. By the ...
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A considerable fraction of radioactivity entering the environment from different nuclear events is associated with particles. The impact of these events can only be fully assessed where there is some knowledge about the mobility of particle bound radionuclides entering the environment. The behavior of particulate radionuclides is dependent on several factors, including the physical, chemical and redox state of the environment, the characteristics of the particles (e.g., the chemical composition, crystallinity and particle size) and on the oxidative state of radionuclides contained in the particles. Six plutonium-containing particles stemming from Runit Island soil (Marshall Islands) were characterized using non-destructive analytical and microanalytical methods. By determining the activity of {sup 239,240}Pu and {sup 241}Am isotopes from their gamma peaks structural information related to Pu matrix was obtained, and the source term was ...
An independent investigation of pipe welding leaks from the Low-Level Waste 2 (LLW2) Skid-B System for the possibilities of improper welding (IW), microbiologically influenced corrosion (MIC), sensitization, chloride pitting corrosion (CPC), and intergranular stress corrosion cracking (IGSCC) was conducted. The results show the prevailing mechanisms that caused the leaks are identified as IW, CPC, and the improper selection of weld filler material for the base metals in an environment of the North Plateau underground water. These is no evidence of MIC, sensitization, or IGSCC. The chloride pitting corrosion mechanism that took place at all the welds are also described. All the pipelines were replaced with polyvinyl chloride (PVC) for cost saving and the LLW2 Skid B System has been successfully operating since 1999. This report summarizes the findings and recommendations associated with preventive measures for future operations. The LLW2 Facility is a replacement ...
Six safety initiatives have been identified for accelerating the resolution of waste tank safety issues and closure of unreviewed safety questions. Safety Initiative 5 is to reduce safety and environmental risk from tank leaks. Item d of Safety Initiative 5 is to complete corrosion studies of single-shell tanks to determine failure mechanisms and corrosion control options to minimize further degradation by June 1994. This report has been prepared to fulfill Safety Initiative 5, Item d. The corrosion mechanisms that apply to Hanford Site single-shell tanks are stress corrosion cracking, pitting/crevice corrosion, uniform corrosion, hydrogen embrittlement, and microbiologically influenced corrosion. The corrosion data relevant to the single-shell tanks dates back three decades, when results were obtained from in-situ corrosion coupons in a few single-shell tanks. Since that time there have been intertank transfers, evaporation, and chemical ...
Gas-insulated systems employing SF/sub 6/ are utilized in a variety of applications in power delivery systems. Because electric arcs, sparks or corona can decompose SF/sub 6/ into byproducts having chemical properties different from SF/sub 6/, environmental concerns arise regarding inadvertent human exposures to electrically-decomposed SF/sub 6/. Biological assays in our laboratory using mammalian cell culture systems have revealed that spark-decomposed SF/sub 6/ produces cell death, and the extent of cell killing increases with increasing spark energy. Chemical analysis of spark-decomposed SF/sub 6/ has identified the major decomposition pathways and byproducts, but biological testing of individual or byproduct mixtures has indicated that these major decomposition products do not contribute, in a significant fashion, to the cell lethality seen in our assays. Further experiments have suggested that S/sub 2/F/sub 10/ may be ...
Peroxisome proliferating agents (PPAs) are a structurally diverse group of chemicals that include environmental chemical contaminants such as certain chlorinated herbicides, solvents and plasticizers. PPAs have previously been shown to induce anti-trout laruci acid hydroxylase immunoreactive proteins in bluegill and catfish. In this investigation, induction of lauric acid hydroxylase activity and immunoreactive proteins was confirmed, and the mass spectral analysis of specific hydroxylation products was performed in order to identify possible species-specific differences in fatty acid metabolism. Male bluegill (Lepomis macrochirus) and channel catfish (Ictalurus punctatus) were administered clofibrate or ciprofibrate 48 hr prior to hepatic or trunk kidney (catfish only) microsome preparation. While no significant differences were observed in male catfish, male bluegill had significant decreases in hematocrit and plasma ...
Microdamage naturally occurs in bone tissue as a result of cyclic loading placed on the body from normal daily activities. While it is usually repaired through the bone turnover process, accumulation of microdamage may result in reduced bone quality and increased fracture risk. It is unclear whether certain areas of bone are more susceptible to microdamage than others due to compositional differences. This study examines whether areas of microdamaged bone are chemically different than undamaged areas of bone. Bone samples (L3 vertebrae) were harvested from 15 dogs. Samples were stained with basic fuchsin, embedded in poly-methylmethacrylate, and cut into 5-(micro)m-thick sections. Fuchsin staining was used to identify regions of microdamage, and synchrotron infrared microspectroscopic imaging was used to determine the local bone composition. Results showed that microdamaged areas of bone were chemically different than the ...
Norway is privileged with extensive resources of natural gas, oil and hydropower. Location of gas fired combined cycle (CC) power plants in Norway offers advantages due to the availability of natural gas from the Norwegian continental shelf and fairly low ambient temperatures, giving high fuel-to-electricity conversion efficiency. The continental shelf provides large storage capacity for CO{sub 2} in deep saline aquifers and in drained gas fields. In this paper the results of extensive work on CO{sub 2} capture carried out during the last years by Statoil in co-operation with several engineering contractors, are presented. The goal has been to develop a commercially viable concept for a combined cycle power plant including CO{sub 2} capture and sequestration. The main concept is based on CO{sub 2} capture from exhaust gas from a combined cycle power plant, using absorption by amine (MEA) solutions. The CO{sub 2} is compressed, transported by pipeline and stored in ...
Computer-Aided Prediction of Chemical Ecotoxicity on the basis of Quantitative Structure-Activity Relationships with the Use of Physico-Chemical Descriptors, Including H-bond Parameters
Cancer, by definition, is a proliferative disease. The fundamental scientific issue explored at the international symposium "Cell Proliferation and Chemical Carcinogenesis" was the impact of chemically...Full Text Available
Chemical leucoderma is an industrial disorder in developed countries and the common causative chemicals are phenols and catechols. Due to stringent controls and preventive measures the incidence has...Full Text Available
The 380 MW combined cycle gas turbine power station in Peterborough changed its water supply from town mains to high purity reverse osmosis permeate in October 2000. The high purity water is produced from secondary treated sewage effluent using advanced membrane technology. Alpheus Environmental and British Gas staff have recently completed a study of the power station's demineralization plant to identify the differences in operating costs associated with the change in feedwater. The results show that the ultrapure water produced after the change to a high purity feed is of improved quality and that the demineralization plant regeneration operating costs have been reduced by over 90%. The demineralization plant availability has increased from 78 to 98% enabling almost 20% more ultra pure water to be produced. The change in feedwater has also improved the local environment by significantly reducing the amount of waste chemicals ...
The 3001 Storage Canal is located under portions of Buildings 3001 and 3019 at Oak Ridge National Laboratory (ORNL) and has a capacity of approximately 62,000 gallons of water. The term canal has historically been used to identify this structure, however, the canal is an in-ground reinforced concrete structure satisfying the regulatory definition of a tank. From 1943 through 1963, the canal in Building 3001 was designed to be an integral part of the system for handling irradiated fuel from the Oak Ridge Graphite Reactor. Because one of the main initial purposes of the reactor was to produce plutonium for the chemical processing pilot plant in Building 3019, the canal was designed to be the connecting link between the reactor and the pilot plant. During the war years, natural uranium slugs were irradiated in the reactor and then pushed out of the graphite matrix into the system of diversion plates and chutes which directed the fuel into the deep ...
Here we describe the use of low energy plasma immersion with active screen as a convenient approach for polypropylene (PP) surface modification. Employing a stainless steel cathodic cage coated with carbon in order to prevent the sputtering of iron from the grid and its deposition onto the polymer sample, the physical chemical properties of PP surface could be effectively modified through the plasma-induced incorporation/formation of nitrogen- and oxygen-containing species. The areal densities of these elements depended on the plasma excitation source, as determined by Rutherford backscattering spectrometry (RBS). Newly formed C-O, C-N, and C=O/O=C-O/N-C=O bonds along with C-C linkages from the PP backbone were identified at the near surface region of the specimens by X-ray photoelectron spectroscopy (XPS). The insertion of such polar reactive functionalities was further confirmed by a substantial decrease in the water contact angle upon plasma ...
Heterogeneous gasless reactive systems, including high-energy density metal-nonmetal compositions, have seen increasing study due to their various applications. However, owing to their high reaction temperature, short reaction time, and small scale of heterogeneity, investigation of their reaction mechanisms and kinetics is very difficult. In this study, microstructural changes and the kinetics of product layer growth in the W-Si system was investigated using a high-speed x-ray phase-contrast imaging technique. Using the Advanced Photon Source of Argonne National Laboratory, this method allowed direct imaging of irreversible reactions in the W-Si reactive system at frame rates up to 36 000 frames per second with 4 {mu}s exposure and spatial resolution of 10 {mu}m. Details of the Si melt and reactions between W and Si, that are unable to be viewed with visible-light imaging, were revealed. These include processes such as the initiation of nucleated melting and other physical phenomena ...
Heterogeneous gasless reactive systems, including high-energy density metal-nonmetal compositions, have seen increasing study due to their various applications. However, owing to their high reaction temperature, short reaction time, and small scale of heterogeneity, investigation of their reaction mechanisms and kinetics is very difficult. In this study, microstructural changes and the kinetics of product layer growth in the W-Si system was investigated using a high-speed x-ray phase-contrast imaging technique. Using the Advanced Photon Source of Argonne National Laboratory, this method allowed direct imaging of irreversible reactions in the W-Si reactive system at frame rates up to 36 000 frames per second with 4 #mu#s exposure and spatial resolution of 10 #mu#m. Details of the Si melt and reactions between W and Si, that are unable to be viewed with visible-light imaging, were revealed. These include processes such as the initiation of nucleated melting and other physical phenomena ...
The reliability of the surface condenser is a key factor in plant performance level and maintenance cost optimization. This is especially the case for thermal nuclear plants where condenser raw wa-ter ingress can introduce contamination into the chemically-controlled, steam/water loop potentially causing damage to sensitive equipment. Two important parameters must be taken into account when attempting to optimize the quality and the reliability of condenser tubing. They include selecting the appropriate material according to the cooling water corrosion level present. A second and equally important parameter is the manufac-turing of the tubing product itself. This paper will identify methods to optimize manufacturing processes and improve tubing quality, according to VALTIMET's 30 years of condenser welded tubing production experience. Those methods complete the core manufacturing process (forming and welding), through improvement of ...
The use of ionic liquids for post combustion capture was discussed. Compared to other solvents, ionic liquids can be used in higher concentrations. Other advantages include the large variation in physical and chemical properties and the non measurable vapor pressure. In this study, 78 different ionic liquids were synthesized and the carbon dioxide absorption rate was measured. The most promising ionic liquids were produced and various tests were made to identify the most suitable absorption solvent. The vapor-liquid equilibrium curve was measured between 40 and 110 degrees C. Pilot plant tests with MEA and one selected ionic liquid test with 30 per cent MEA at the pilot plant at the EVNs Duernrohr Power Station in Lower Austria are running successfully with a capture performance of approximately 87 per cent. The experiments will provide a direct comparison of the energy demand and capture performance between the MEA and the ionic liquids.
Fe-Cu binary alloys are often used to mimic the behaviour of reactor pressure vessel steels. Their study allows identifying some of the defects responsible for irradiation-induced hardening. But recently the influence of manganese and nickel in low-Cu steels has been found to be important as well. In contrast with existing models found in the literature, which predict that hardening saturates after a certain dose, Fe alloys containing nickel and manganese irradiated in a material test reactor (BR2) show a continuous increase of hardening, up to doses equivalent to about 40 years of operation. Considerations based on positron annihilation spectroscopy analyses suggest that the main objects causing hardening in Cu-free alloys are most probably self-interstitial clusters decorated with manganese. In low-Cu reactor pressure vessel steels and in Fe-CuMnNi alloys, the main effect is still due to Cu-rich precipitates at low doses, but the role of manganese-related ...
The Idaho Chemical Processing Plant (ICPP) Water inventory Study was initiated in September 1993 with the formation of a joint working group consisting of representatives from DOE-ID, State of Idaho INEL Oversight Program, US Geological Survey, and INEL employees to investigate three issues that had been identified by the INEL Oversight Program at ICPP: (1) the water inventory imbalance at ICPP, (2) the source of water infiltrating into the Tank Farm vault sumps, and (3) the source of water providing potential recharge to perched water bodies underlying ICPP. These issues suggested that water was being lost from the ICPP distribution system. The INEL Oversight Program was concerned that the unaccounted for water at ICPP could be spreading contaminants that have been released over the past 40 years of operations of ICPP, possibly to the Snake River Plain Aquifer. This report summarizes the findings of each of the component investigations that ...
Magnetic particles (MAG*SEP"S"M) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEP"S"M particles were coated with (1) clinoptilolite, (2) transylvanian volcanic tuff, (3) resorcinol formaldehyde, and (4) crystalline silico-titanate, and then were contacted with a Hanford supernatant simulant. Particles coated with the crystalline silico-titanate were identified by Bradtec as having the highest capacity for cesium removal under the conditions tested (variation of pH, ionic strength, cesium concentration, and absorbent/solution ratio). The MAG*SEP"S"M particles coated with resorcinol formaldehyde had high distribution ratios values and could also be used to remove cesium from Hanford supernant simulant. Gamma irradiation studies were performed on the MAG*SEP"S"M particles with a gamma dose equivalent to 100 cycles of use. This irradiation decreased the loading ...
One of the principal problems confronting the remediation of Bear Creek Valley is the cleanup of contaminated groundwater. The S-3 Site is one of the locations in the valley where groundwater is most contaminated, and contamination from the S-3 Site has also caused extensive contamination of downgradient groundwater. This groundwater plume, therefore, has a high priority in the Bear Creek Valley remedial process. Pumping and treating groundwater was identified early in the feasibility study as a likely remedial alternative for the S-3 Site groundwater plume. The hydrology and geochemistry of the plume are extremely complex. There is a high degree of uncertainty in the current understanding of how the aquifer will react physically and chemically to pumping, making evaluation of a pump-and-treat alternative impractical at the present time. Before a pump-and-treat alternative can be evaluated, its technical practicability, effectiveness, and ...
A mixture of long-chain hydrocarbons constituted by nonacosane (29C, 7.5%), hentriacontane (31C, 48.3%), and tritriacontane (33C, 30.1%), the ester 1?-acetyloxymethylpentacosa-20?-enyl 10-hydroxydecanoate (2), ?-amyrin (3), friedelin (4), and lupeol (5), and 3?-hydroxy-D:B-friedo-olean-5-ene (6) were identified as constituents of fruits of Maytenus salicifolia Reissek (Celastraceae). The structural formula and the stereochemistry of compound 6 were established by the data obtained through 1H and 13C NMR spectroscopy, including DEPT-135 and 2D (HMQC, HMBC, and NOESY) experiments. By analysis of the spectral data, it was possible to correct seven chemical shift assignments of compound 6, which were erroneous attributed and published in the scientific literature.
A carbon-bonded carbon fiber (CBCF) insulation developed for a radioisotope heat source is made from chopped rayon fiber about 10..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF is an excellent lightweight insulating material with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W/(m-K) in vacuum at 2000/sup 0/C. (Several attributes that make CBCF particularly suitable for the heat source application have been identified.) These include light weight, low thermal conductivity, chemical compatibility, and hightemperature capabilities. The mechanical strength of CBCF insulation is satisfactory for the application. The basic fabrication technique was refined to eliminate undesirable large pores and cracks often present in materials fabricated by earlier techniques. Also, processing was scaled up to increase the fabrication rate by a factor of 10. The specific properties of the CBCF were ...
A carbon-bonded carbon fiber (CBCF) insulation developed for a radioisotope heat source is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF is an excellent lightweight insulating material with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W/(m-K) in vacuum at 2000/sup 0/C. Several attributes that make CBCF particularly suitable for the heat source application have been identified. These include light weight, low thermal conductivity, chemical compatibility, and high-temperature capabilities. The mechanical strength of CBCF insulation is satisfactory for the application. The basic fabrication technique was refined to eliminate undesirable large pores and cracks often present in materials fabricated by earlier techniques. Also, processing was scaled up to increase the fabrication rate by a factor of 10. The specific ...
In the present dissertation, a hierarchical multiscale approach for modeling FePt nanoparticles by atomistic computer simulations is developed. By describing the interatomic interactions on different levels of sophistication, various time and length scales can be accessed. Methods range from static quantum-mechanic total-energy calculations of small periodic systems to simulations of whole particles over an extended time by using simple lattice Hamiltonians. By employing these methods, the energetic and thermodynamic stability of non-crystalline multiply twinned FePt nanoparticles is investigated. Subsequently, the thermodynamics of the order-disorder transition in FePt nanoparticles is analyzed, including the influence of particle size, composition and modified surface energies by different chemical surroundings. In order to identify processes that reduce or enhance the rate of transformation from the disordered to the ordered state, the ...
The US Environmental Protection Agency (EPA) conducted a cost-effectiveness (CE) analysis to estimate the incremental cost of complying with the proposed effluent limitation guidelines (ELGs) for the coastal oil and gas industry (EPA 1995a). EPA`s CE analysis calculates the pounds of each pollutant that would be removed if the chosen discharge option is selected. In 1993, EPA issued final ELGs for the offshore oil and gas industry and published an offshore CE analysis. The chemical characteristics of produced water from the offshore region are essentially the same as those of produced water from the coastal region. It was surprising, therefore, that EPA chose a much longer list of pollutants and generally stricter weighting factors for the coastal CE analysis. This report reviews the data, assumptions, and analyses used in EPA`s coastal CE analysis and identifies alternate data, assumptions, and analyses that could lead to significantly ...
This project was supported through ERDA to demonstrate that the temporal distribution of tritium can be documented by the analysis of bound hydrogen in annual tree-ring samples. The project focuses on two sample locations at the Savannah River Site (SRS), a nuclear material production facility located in Aiken, SC. The SRS provided samples of cross-sections from a single tree that were to be pooled together for analysis. Annual tree-rings were identified in each cross-section sample and separated for the period 1954 to 1993. These annual samples were ground and chemically treated to separate the hollocellulose fraction of the wood, then subsequently combusted and the resulting water counting using low-level liquid scintillation counting equipment. Additionally, the ground annual tree-rings were gamma-counted to determine any temporal variation in radionuclide activity and analyzed with x-ray fluorescence to find any temporal variation in ...
Ex situ and in situ fuel cell degradation of a sPAEK membrane were investigated. Post-mortem analyses of the aged membrane and of the degradation products eluted in water were carried out by NMR, IR, SEC and EDX. Ex situ agings were performed in a low concentration H{sub 2}O{sub 2} solution (0.07%) without any metallic catalyst. We exemplify that ex situ accelerated aging tests in such hydrogen peroxide solution are relevant to the chemical degradation in fuel cell. We have shown that a 500 h fuel cell test at moderate temperature (60 C) induces significant modifications on the macromolecules such as a 40% molecular weight reduction. Degradation appears heterogeneous and limited to the cathode side. The model compound approach developed in the previous article (Perrot et al.) has allowed the identification of the aging path in fuel cell. Phenolic and carboxylic acid chain ends have been identified as the main products resulting from polymer ...
This work plan has been prepared to document the scoping and planning process performed by the US Department of Energy (DOE) to support remedial action activities at the Colonie site. The site is located in eastern New York State in the town of Colonie near the city of Albany. Remedial action of the Colonie site is being planned as part of DOE's Formerly Utilized Sites Remedial Action Program. The DOE is responsible for controlling the release of all radioactive and chemical contaminants from the site. Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), a remedial investigation/feasibility study (RI/FS) must be prepared to support the decision-making process for evaluating remedial action alternatives. This work plan contains a summary of information known about the site as of January 1988, presents a conceptual site model that identifies potential routes of human exposure to site containments, ...
This paper surveys the publications available in the literature concerning the application of the second-law of thermodynamics to internal combustion engines. The availability (exergy) balance equations of the engine cylinder and subsystems are reviewed in detail providing also relations concerning the definition of state properties, chemical availability, flow and fuel availability, and dead state. Special attention is given to identification and quantification of second-law efficiencies and the irreversibilities of various processes and subsystems. The latter being particularly important since they are not identified in traditional first-law analysis. In identifying these processes and subsystems, the main differences between second- and first-law analyses are also highlighted. A detailed reference is made to the findings of various researchers in the field over the last 40 years concerning all types of internal ...
The gas-phase reaction of benzene with O(3P) is of considerable interest for modeling of aromatic oxidation, and also because there exist fundamental questions concerning the prominence of intersystem crossing in the reaction. While its overall rate constant has been studied extensively, there are still significant uncertainties in the product distribution. The reaction proceeds mainly through the addition of the O atom to benzene, forming an initial triplet diradical adduct, which can either dissociate to form the phenoxy radical and H atom, or undergo intersystem crossing onto a singlet surface, followed by a multiplicity of internal isomerizations, leading to several possible reaction products. In this work, we examined the product branching ratios of the reaction between benzene and O(3P) over the temperature range of 300 to 1000 K and pressure range of 1 to 10 Torr. The reactions were initiated by pulsed-laser photolysis of NO2 in the presence of benzene and helium buffer in a ...
The Formerly Utilized Sites Remedial Action Program (FUSRAP) of the Department of Energy is designed to identify and evaluate the radiological conditions at sites formerly used by the Corps of Engineers Manhattan Engineer District and the US Atomic Energy Commission. Where required, remedial action will be instituted to remove potential restrictions on the use of the sites due to residual low-level radioactive contamination. A total of 31 sites that may require remedial action has been identified. The purpose of the Ocean FUSRAP Program, which began in March 1981, is to assess the technical, environmental, and institutional feasibility of disposing, in the ocean and on the ocean floor, of FUSRAP soil and rubble which contains traces of natural radioactive materials. The initial focus has been on the Middlesex, New Jersey, Sampling Plant site and surrounding properties, which contain on the order of 100,000 metric tons of material. The Belgian ...
The Formerly Utilized Sites Remedial Action Program (FUSRAP) of the Department of Energy is designed to identify and evaluate the radiological conditions at sites formerly used by the Corps of Engineers Manhattan Engineer District and the US Atomic Energy Commission. Where required, remedial action will be instituted to remove potential restrictions on the use of the sites due to residual low-level radioactive contamination. A total of 31 sites that may require remedial action has been identified. The purpose of the Ocean FUSRAP Program, which began in March 1981, is to assess the technical, environmental, and institutional feasibility of disposing, in the ocean and on the ocean floor, of FUSRAP soil and rubble which contains traces of natural radioactive materials. The initial focus has been on the Middlesex, New Jersey, Sampling Plant site and surrounding properties, which contain on the order of 100,000 metric tons of material. The Belgian ...
The Phase I feasibility study has focused on determining the availability of information for estimating exposures of the public to chemicals and radionuclides released as a result of historical operation of the facilities at the Oak Ridge Reservation (ORR). The estimation of such past exposures is frequently called dose reconstruction. The initial project tasks, Tasks 1 and 2 were designed to identify and collect information that documents the history of activities at the ORR that resulted in the release of contamination and to characterize the availability of data that could be used to estimate the magnitude of the contaminant releases or public exposures. A history of operations that are likely to have generated off-site releases has been documented as a result of Task 1 activities. The activities required to perform this task involved the extensive review of historical operation records and interviews with present and past employees as well ...
Half-Heusler phases XYZ (Pearson symbol cF12) are chemically versatile and rich in physical properties. The half-Heusler phase in the Fe-Zn-Sb ternary system was reported in the year 2000. In this work, two new ternary phases are identified in the vicinity of the equiatomic composition FeZnSb in the same system: Fe1-xZnSb (tetragonal, space group P4/nmm, Pearson symbol tP6-?, Z=2: a=4.1113(6) A, c=6.0127(12) A for x=0.08 (1), and a=4.1274(6) A, c=6.0068(12) A for x=0.12 (2)); and Fe7.87Zn6.72Sb8 (Fe0.98Zn0.84Sb) (3) (cubic, space group Fm-3m, Pearson symbol cF96-?, Z=4, a=11.690(13) A). 1 and 2 crystallize in the PbFCl-type structure, and 3 adopts a unique 2x2x2 supercell of a normal half-Heusler structure. The structures of both the tetragonal and cubic phases can be described as assemblies of half-Heusler structure related subunits. Electrical resistivity measurement on the pure sample of 2 shows it has metallic-like behavior, and its thermal ...
This report is the first of four volumes that identify and assess the environmental, health, and safety issues involved in using sodium-sulfur (Na/S) battery technology as the energy source in electric and hybrid vehicles that may affect the commercialization of Na/S batteries. This and the other reports on recycling, shipping, and vehicle safety are intended to help the Electric and Hybrid Propulsion Division of the Office of Transportation Technologies in the US Department of Energy (DOE/EHP) determine the direction of its research, development, and demonstration (RD&D) program for Na/S battery technology. The reports review the status of Na/S battery RD&D and identify potential hazards and risks that may require additional research or that may affect the design and use of Na/S batteries. This volume covers cell design and engineering as the basis of safety for Na/S batteries and describes and assesses the potential ...
This report is the first of four volumes that identify and assess the environmental, health, and safety issues involved in using sodium-sulfur (Na/S) battery technology as the energy source in electric and hybrid vehicles that may affect the commercialization of Na/S batteries. This and the other reports on recycling, shipping, and vehicle safety are intended to help the Electric and Hybrid Propulsion Division of the Office of Transportation Technologies in the US Department of Energy (DOE/EHP) determine the direction of its research, development, and demonstration (RD D) program for Na/S battery technology. The reports review the status of Na/S battery RD D and identify potential hazards and risks that may require additional research or that may affect the design and use of Na/S batteries. This volume covers cell design and engineering as the basis of safety for Na/S batteries and describes and assesses the potential ...
Besides differentiation and apoptosis, cell migration is a basic process in brain development in which neural cells migrate several centimeters within the developing brain before reaching their proper positions and forming the right connections. For identifying signaling events that control neural migration and are therefore potential targets of chemicals to disturb normal brain development, we developed a human neurosphere-based migration assay based on normal human neural progenitor (NHNP) cells, in which the distance is measured that cells wander over time. Applying this assay, we investigated the role of the extracellular signal-regulated kinases 1 and 2 (ERK1/2) in the regulation of NHNP cell migration. Exposure to model substances like ethanol or phorbol 12-myristate 13-acetate (PMA) revealed a correlation between ERK1/2 activation and cell migration. The participation of phospho-(P-) ERK1/2 was confirmed by exposure of the cells to the ...
In-vitro experiments using "2"0"3Pb were performed to identify the lead binding components in human peripheral blood. The distribution of lead in plasma, in the red cell membrane, and within the red cell was also investigated. Studies of the distribution of "2"0"3Pb in the whole blood showed that at a lead concentration of 2.45 #mu#mol/l (50 #mu#g/100 ml) about 94% of lead had been incorporated by the erythrocytes and 6% remained in the plasma. After extraction of lipid by a methanol/chloroform mixture, about 75% of the lead was found to be associated with the protein fraction. The lipid contained about 21% of the "2"0"3Pb, the remainder being in the aqueous plasma. SDS polyacrylamide gel electrophoresis of blood plasma showed that almost 90% of the "2"0"3Pb was present in the albumin fraction; the remainder was likely to be associated with high molecular weight globulins. Several binding sites were identified on the erythrocyte membrane. The ...
The aim of this work is to compile an inventory of the main characteristics (chemical, morphological, mineralogical and grain size parameters) of the bulk cargo materials and of the material emitted during different port operations for possible use as tracers of the fugitive PM emission sources. For all cases, the tracer characteristics determined for each bulk material were also identified in the corresponding PM material emitted. This inventory could assist the harbour authorities to identify the origin of high PM events recorded by air quality monitoring networks in harbour areas, and could also help modellers to predict the impact of harbour activities on ambient PM levels. The harbour of Tarragona (north-east Spain) was selected for this study given the high volume of solids in bulk handled. To this end, 12 handling operations of selected materials (clinker, phosphate, pyrite ash, Mn mineral, fine Si-Mn, coke (coal), ...
Chemical oxidation is a treatment technology that uses powertul chemical oxidizers to destroy organic contaminants. Typical oxidizers used in chemical oxidation processes include ozone, hydrogen peroxide, chlorine, and potassium permanganate. The chemical reaction products are usually simple organic compounds, such as carboxylic acids, and/or inorganic compounds, such as carbon dioxide, water, and simple inorganic complexes (e.g., chloride salts, in the case of chemical oxidation treatment of chlorinated solvents).
Coatings and sensors having both steric and chemical selectivity. Controlled porosity provides the steric selectivity, whereas chemically tailored film properties, using controlled composition or modification by coupling agents, chemical species replacement, or chemical species within pores, provide the chemical selectivity. Single or multiple layers may be provided.
Sulfur K-edge X-ray absorption spectroscopy is a powerful in situ probe of sulfur biochemistry in intact cells and tissues. Under favorable circumstances the technique can provide quantitative information on the chemicalidentify of the sulfur species that are present in a sample. Prange et al. have recently reported an X-ray absorption spectroscopic study of bacterial sulfur storage globules. Unfortunately there are substantial problems with the experimental technique employed that, they contend, lead to completely erroneous conclusions. In the more recent of their two papers Prange et al. employed a curve-fitting method similar to that used by us (for more than 10 years). In essence, the method employs simply fitting a linear combination of the spectra of standard compounds to that of the unknown, in this case cultures of bacterial cells. This type of analysis can provide quantitative estimates of the individual sulfur types in the sample, ...
The steroidogenic factor 1 (SF-1, also known as NR5A1) is a transcription factor belonging to the nuclear receptor superfamily. Whereas most of the members of this family have been extensively characterized, the therapeutic potential and pharmacology of SF-1 still remains elusive. Described here is the identification and characterization of selective inhibitory chemical probes of SF-1 by a rational ultra-high-throughput screening (uHTS) strategy. A set of 64,908 compounds from the National Institute of Health's Molecular Libraries Small Molecule Repository was screened in a transactivation cell-based assay employing a chimeric SF-1 construct. Two analogous isoquinolinones, ethyl 2-[2-[2-(2,3-dihydro-1,4-benzodioxin-7-ylamino)-2-oxoethyl]-1-oxoisoquinolin-5-yl]oxypropanoate (SID7969543) and ethyl 2-[2-[2-(1,3-benzodioxol-5-ylmethylamino)-2-oxoethyl]-1-oxoisoquinolin-5-yl]oxypropanoate and (SID7970631), were identified as potent submicromolar ...
The ash of biomass fuels was analysed in order to identify its inorganic chemical characteristics. The experiments were carried out using different methods of extraction. The accuracy of the measurements was verified by comparative analyses using certified samples. The composition was shown to vary with the fuel type and ash fraction. In the case of arsenic and the toxic heavy metals cadmium, mercury and lead, accumulation factors of 1.4 to 43 were measured in the tissue filter ash. [German] Fuer die Bestimmung der stofflichen Eigenschaften von Biobrennstoffaschen werden neben der fuer die Ermittlung von Stoffbilanzen notwendigen Analyse der Gesamtgehalte, in Abhaengigkeit von der Zielsetzung und den gesetzlichen Vorgaben, unterschiedliche Extraktionsverfahren eingesetzt. Fuer die Gesamtgehaltsbestimmung wurden aus laborinternen Wiederholungsuntersuchungen sowie einem laborexternen Analysenvergleich Kenngroessen fuer die Praezision und ...
The object of this paper is to identify the key elements that impact a radiation dose at EAB (Exclusion Area Boundary). This study is based on the AST (Alternative Source Terms) as defined in Regulatory Guide 1.183. The LOCA (Loss of Coolant Accident) and the LRA (Locked Rotor Accident) are selected as limiting cases. A sensitivity analysis of accidental behavior with respect to various parameters during LOCA and LRA at Kori Unit 1 is also undertaken for the following objectives: to determine the limiting parameters, to find the impact trend of the radiation dose, and to find the safety margin between AST and TID (Technical Information Document) methodologies. This work confirms that key parameters are particulate removal rate, decontamination factor, iodine chemical form, gap fraction, partitioning factor, and the impact of isotopes group. Comparing TID with AST, the radiation dose of TID is about 80% greater than that of AST under a LOCA, and ...
Aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), a sterically hindered amine, was examined as a potential CO{sub 2} absorbent and compared with the most commonly used absorbent, monoethanolamine (MEA) solution, through equilibrium solubility measurements and {sup 13}C NMR spectroscopic analyses. The solubilities of CO{sub 2} in aqueous 10 mass % AHPD solutions were higher than those in aqueous 10 mass% MEA solutions above 4 kPa at 298.15 K, but lower below 4 kPa. The solubility difference between these two solutions increased with the CO{sub 2} partial pressures above the crossover pressure. Equilibrated CO{sub 2}-MEA-H{sub 2}O and CO{sub 2}-AHPD-H{sub 2} solutions at various CO{sub 2} partial pressures ranging from 0.01 to 3000 kPa were analyzed by {sup 13}C NMR spectroscopy. AHPD contains more hydroxyl groups than nonhindered MEA, and hence the chemical shifts in its {sup 13}C NMR spectra were strongly influenced by the solution pH values. In ...
Effective commercial liquid absorption technology currently applicable for CO{sub 2} capture from power plant flue gases uses a conventional chemical solvent, MEA(monoethanolamine), which was developed over 60 years ago as general non selective solvent to remove acid gases from natural gas streams. The application to CO{sub 2} capture from almost atmospheric pressure flue gases required modification of the technology on account of the oxygen content to incorporate inhibitors to resist solvent degradation and equipment corrosion, as well as upstream treatment of the flue gases to remove both SO{sub x} and NO{sub x} present. The solvent strength used by such processes is relatively low in comparison with high strength modern chemical solvents. The resultant effect is large equipment and high regeneration energy requirements which is a parasitic load on the power plant. Using current technology for CO{sub 2} capture from flue gas derived from ...
The toxicities of 21 different herbicides to algae (Selenastrum capricornutum and Chlorella vulgaris) and to terrestrial plants (radishes, barley, and bush beans or soybeans) were compared to order to determine the feasibility of using a short-term (96-h) algal growth inhibition test for identifyingchemicals having potential toxicity in a 4-week terrestrial plant bioassay. The toxicity of each test chemical, usually in combination with a commercial formulation, was evaluated at six nominal concentrations, between 0 and 100 mg/L growth medium in the algal bioassay or between 0 and 100 mg/kg substate in the terrestrial plant bioassay, in terms of both (1) the no-observed-effect concentration (NOEC), i.e., the highest concentration tested at which no significant (P < 0.05, one-sided test) reduction in algal growth rate or in terrestrial plant yield, relative to controls, was observed; and (2) the concentration at which ...
Detailed chemical kinetic reaction mechanisms have been developed to describe the pyrolysis and oxidation of the n-alkanes, including n-octane (n-C{sub 8}H{sub 18}), n-nonane (n-C{sub 9}H{sub 20}), n-decane (n-C{sub 10}H{sub 22}), n-undecane (n-C{sub 11}H{sub 24}), n-dodecane (n-C{sub 12}H{sub 26}), n-tridecane (n-C{sub 13}H{sub 28}), n-tetradecane (n-C{sub 14}H{sub 30}), n-pentadecane (n-C{sub 15}H{sub 32}), and n-hexadecane (n-C{sub 16}H{sub 34}). These mechanisms include both high temperature and low temperature reaction pathways. The mechanisms are based on previous mechanisms for n-heptane, using the same reaction class mechanism construction developed initially for n-heptane. Individual reaction class rules are as simple as possible in order to focus on the parallelism between all of the n-alkane fuels included in the mechanisms, and there is an intent to develop these mechanisms further in the future to incorporate greater levels of accuracy and predictive ...
This thesis deals with the evaluation of Solar Grade Silicon (SoG-Si) purified by different techniques, and also the fabrication and characterization of high efficiency and advanced bifacial solar cells. In the beginning of Chapter 1, various SoG-Si production methods relevant for this work are qualitatively described. The three feedstock materials used in this work are from the Fluidized Bed Reactor (FBR) process, metallurgical feedstock-I and feedstock-II process. In metallurgical feedstock-I, the lifetime of the minority charge carriers in multicrystalline silicon (mc-Si) samples at the grain boundaries are found to be higher than the grains themselves possibly due to lower resistivities in the grain boundaries. The efficiency of the best solar cell obtained using the mc-Si metallurgical feedstock-I is 16.1%. It has been identified that the fast light induced degradation, whose magnitude is lower than that of a reference cell suggests the formation of a B-metal ...
Three blocks of non-welded tuff, one nominally one cubic foot (trial block) in volume and the other two, nominally one cubic meter (1 m3) in volume, were excavated from the Busted Butte Test Facility on the Nevada Test Site in 1999 and transported to the Atomic Energy of Canada Limited Whiteshell Laboratories in Pinawa, Manitoba. The trial block and one of the 1-m3 blocks were used for radionuclide migration experiments under unsaturated conditions; the remaining 1-m3 block was used for similar migration experiments under saturated conditions. After a vertical flow of synthetic transport solution was set up under unsaturated conditions, a suite of conservative and chemically reactive radionuclide tracers was injected at volumetric flow rates of 20 mL/hr in the trial block, and 10 mL/hr in two locations on the upper surface of the 1-m3 block. These flow rates correspond to infiltration rates of about 120 cm/year and about 17 cm/year, respectively. The duration of ...
Comparative studies of flocculent and grand-design spirals suggest that density waves are not the predominant trigger of star formation in most galaxies. Implications for chemical evolution are profound. It may be possible to ignore the details of the spiral-wave phenomenon in research aimed at unifying the chemical properties of spiral disks. 16 references.
BackgroundA key question in the risk assessment of exposures to multiple chemicals is whether mixture effects may occur when chemicals are combined at low doses which individually...Full Text Available
Simultaneous or prior exposure to one chemical may alter the concurrent or subsequent response to another chemical, often in unexpected ways. This is particularly true when the two chemicals...Full Text Available
Environmental chemicals that function as estrogens have been suggested to be associated with an increase in disease and dysfunctions in animals and humans. To characterize chemicals that may act as...Full Text Available
An approach to generate mimics of phosphorylated serine proteins chemically through site-specific sulfonation of cysteine is presented. This chemical modification is reversible in the presence of reducing agent and therefore is analogous to the kinase/phosphatase system used in nature. PMID:21717004
The experimental data set used to evaluate site-specific histopathologic correspondence between the morphologic end points of toxicity and carcinogenicity comprises 130 chemical carcinogenesis studies....Full Text Available
An IAEA databank lists a number of reported cases of illicitly trafficked nuclear or other radioactive materials. Apart from the traditional concern with nuclear proliferation, the post September 11th public is now wary of a possible attack by terrorists with a nuclear or radiation dispersion device (RDD). Until now, the seized quantities have not been sufficient to manufacture a nuclear explosive device, but they might be enough to construct an RDD. Recognizing the latent global challenge to public health and safety, the G8 States (Japan, USA, Germany, France, UK, Italy, Canada, and Russia) have called for 'joint international efforts to identify and suppress illicit supply' of, and demand for, nuclear material and to deter potential traffickers. One measure gaining in significance is to identify seized material and trace it back to its origin the objective of an emerging science known as nuclear forensics. Repeatedly nuclear or other ...
Here we examine Fe speciation within Fe-encrusted biofilms formed during 2-month seafloor incubations of sulfide mineral assemblages at the Main Endeavor Segment of the Juan de Fuca Ridge. The biofilms were distributed heterogeneously across the surface of the incubated sulfide and composed primarily of particles with a twisted stalk morphology resembling those produced by some aerobic Fe-oxidizing microorganisms. Our objectives were to determine the form of biofilm-associated Fe, and identify the sulfide minerals associated with microbial growth. We used micro-focused synchrotron-radiation X-ray fluorescence mapping (mu XRF), X-ray absorption spectroscopy (mu EXAFS), and X-ray diffraction (mu XRD) in conjunction with focused ion beam (FIB) sectioning, and highresolution transmission electron microscopy (HRTEM). The chemical and mineralogical composition of an Fe-encrusted biofilm was queried at different spatial scales, and the spatial ...
Complete text of publication follows. Baikal is an ancient unique lake. The sweet water of Baikal is crystal clean; it concentrates oxygen and contains scarce silicon. This feature is provoked very particular interest for scientists and poses some awkward questions concerning the preservation of Baikal's ecosystem. A profound investigation of fish otholiths, animal teeth, sponges, valves of mollusks and diatom algae provides chronological information, possibility to reconstruct the events proceeding in the environment based on variations of their chemical composition. Because these study objects are small-sized, and some of them are micron-size, application of the electron-probe microanalysis turns to be quite productive. The goal of this study is to disclose performance capabilities of this method while investigating the Baikal flora and fauna. Investigations were performed by devices JCXA-733 and JXA-8200 using the electron microscope and x-ray microprobe modes. ...
There are very different views on the health hazards of DU munitions. Most of the concerns of veterans and their advisors focus on the radiological effects of DU and consequently these are the focus of this editorial. Effects on the kidney and environmental consequences are, however, considered in the second of the Royal Society reports and the main conclusions of both of the reports are outlined in the summary document published in this issue of the journal. The main radiological concerns focus on the irradiation of lung tissues from inhaled DU particles and irradiation resulting from the translocation of inhaled particles to the thoracic lymph nodes.The overwhelming scientific view, presented in the two Royal Society reports and in other independent reviews, is that the main risks of exposure to DU aerosols are an increase in lung cancer and (from chemical toxicity) damage to the kidney, although these are likely to be evident only following substantial intakes. ...
The Molecular Genetics and Carcinogenesis Section conducts studies using human epithelial cells to assess: activation of proto-oncogenes by chemical and physical carcinogens; inactivation and dysregulation of tumor suppressor genes by chemical and physical
Hard Nano-Strutural Coatings Resistant to the Extreme Conditions of Chemical, Abrasive and High Energy Media for Thermonuclear Power, Oil and Gas and Chemical Industries
Immunomodulation by environmental chemical contaminants and the role immune parameters play in toxicity and risk assessment studies is of increasing concern. Although considerable evidence has indicated...Full Text Available
Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and...Full Text Available
The immune system plays a crucial role in maintaining health; however, accumulating evidence indicates that this system can be the target for immunotoxic effects caused by a variety of chemicals including...Full Text Available
The existence of thresholds for toxicants is a matter of debate in chemical risk assessment and regulation. Current risk assessment methods are based on the assumption that, in the absence of sufficient...Full Text Available
The goal of this project is to provide materials engineers, chemical engineers and plant operators with a software tool that will enable them to predict localized corrosion of process equipment including fabricated components as well as base alloys. For design and revamp purposes, the software predicts the occurrence of localized corrosion as a function of environment chemistry and assists the user in selecting the optimum alloy for a given environment. For the operation of existing plants, the software enables the users to predict the remaining life of equipment and help in scheduling maintenance activities. This project combined fundamental understanding of mechanisms of corrosion with focused experimental results to predict the corrosion of advanced, base or fabricated, alloys in real-world environments encountered in the chemical industry. At the heart of this approach is the development of models that predict the fundamental parameters ...
The zinc-blende (ZB) and wurtzite (W) structures are the most common crystal forms of binary octet semiconductors. In this work we have developed a simple scaling that systematizes the {ital T}=0 energy difference {Delta}{ital E}{sub W{minus}ZB} between W and ZB for all simple binary semiconductors. We have first calculated the energy difference {Delta}{ital E}{sub W{minus}ZB}{sup LDF}({ital AB}) for AlN, GaN, InN, AlP, AlAs, GaP, GaAs, ZnS, ZnSe, ZnTe, CdS, C, and Si using a numerically precise implementation of the first-principles local-density formalism (LDF), including structural relaxations. We then find a {ital linear} scaling between {Delta}{ital E}{sub W{minus}ZB}{sup LDF}({ital AB}) and an atomistic orbital-radii coordinate {ital {tilde R}}({ital A},{ital B}) that depends only on the properties of the free atoms {ital A} and {ital B} making up the binary compound {ital AB}. Unlike classical structural coordinates (electronegativity, atomic sizes, electron count), {ital {tilde ...
The effective remediation of contaminated sites requires accurate identification of chemical distributions. A rapid sampling method using passive sampling devices (PSDs) can provide a thorough site assessment. We have been pursuing their application in terrestrial systems and have found that they increase the ease and speed of analysis, decrease solvent usage and overall cost, and minimize the transport of contaminated soils. Time and cost savings allow a higher sampling frequency than is generally the case using traditional methods. PSDs have been used in the field in soils of varying physical properties and have been successful in estimating soil concentrations ranging from 1 {mu}g/kg (parts per billion) to greater than 200 mg/kg (parts per million). They were also helpful in identifying hot spots within the sites. Passive sampling devices show extreme promise as an analytical tool to rapidly characterize contaminant distributions in soil. ...
In order to predict thermal hazards of high-energy materials, accurate kinetics constants must be determined. Predictions of thermal hazards for mixtures of high-energy materials require measurements on the mixtures, because interactions among components are common. A differential-scanning calorimeter (DSC) can be used to observe rate processes directly, and isothermal methods enable detection of mechanism changes. Rate-controlling processes will change as components of a mixture are depleted, and the correct depletion function must be identified for each specific stage of a complex process. A method for kinetics measurements on mixed explosives can be demonstrated with Composition B is an approximately 60/40 mixture of RDX and TNT, and is an important military explosive. Kinetics results indicate that the mator process is the decomposition of RDX in solution in TNT with a perturbation caused by interaction between the two components. It is concluded that a ...
The hardening and embrittlement of reactor pressure vessel (RPV) steels is of great concern in the actual nuclear power plant life assessment. This embrittlement is caused by irradiation-induced damage, like vacancies, interstitials, solutes and their clusters. The current procedure to estimate material properties for the irradiated pressure vessels is based on Charpy-V tests of identical material located at the inner shell of the reactor. But the reason for the embrittlement of the materials is not yet totally known. The real nature of the irradiation damage should thus be examined as well as its evolution in time. Fe-Cu binary alloys are often used to mimic the behaviour of such steels. Their study allows. Identifying some of the defects responsible of the hardening, especially when compared to pure iron or C-micro-alloyed iron. More recently the influence of manganese and nickel in low-Cu RPV steels has become a significant topic. Thus in contrast with the ...
This project has been concerned with the understanding of certain key physical and physical chemical properties of polymeric systems which are related to their use as working substances in mechanochemical systems. Since the crystal-liquid phase transition is involved in the process of interest, attention has been focused on this transition and on the properties of semi-crystalline polymers. Two kinds of behavior and properties have been studied in this program. One of these is concerned with melting-crystallization under an applied external force. Here the primary matters of concern are the equilibrium melting temperature-stress relations and the associated problem of crystallization kinetics under an applied external stress. The other area of study involves mechanical properties, with particular emphasis on the influence of the morphological and structural variables which describe the semi-crystalline state. We have taken advantage in this work of concurrent ...
Carbonyl compounds constitute an important reactive class of non methane volatile organic compounds. They can be emitted directly to the atmosphere from primary sources such as combustion engines, landfills and wastewater surfaces or as secondary products by the photochemical oxidation of hydrocarbons and other volatile organic compounds 1-3. Carbonyls photo-oxidize during the day to produce toxic radicals such as OH, HO_2, RO and RO_2. These species react with nitrogen oxides (NOx) and other VOCs present in the atmosphere to form tropospheric ozone (O_3); a highly reactive oxidizing agent that is harmful to human health, agricultural products and climate 4, 5. Hence identifying the levels and sources of ozone precursors such as low carbonyls, carbon monoxide (CO) and NOx derivatives, and understanding their physical and chemical transformation in the troposphere is an important task due to their atmospheric and adverse health implications. ...
Epidermal growth factor receptor (EGFR) gene alterations have been found in human lung cancers. However, there is no information on the factors inducing EGFR mutations. In rodents, K-ras mutations are frequently found in many lung carcinogenesis models, but hitherto, Egfr mutations have not been reported. Their presence was therefore investigated in representative lung carcinogenesis models with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-nitrosobis(2-hydroxypropyl)amine (BHP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MelQx) and ethyl carbamate (urethane), as well as X-ray irradiation. With the chemical carcinogenesis models, no mutations were detected in Egfr, which is in clear contrast to the high rates observed in either codon 12 or 61 of K-ras (21/23 of the lung tumors induced with NNK, 4/5 with MelQx, 1/4 with urethane and 7/18 with BHP). However, in the X-ray-induced lung tumors, Egfr mutations with amino acid substitution were observed in ...
A core competency is a distinguishing integration of capabilities which enables an organization to deliver mission results. Core competencies represent the collective learning of an organization and provide the capacity to perform present and future missions. Core competencies are distinguishing characteristics which offer comparative advantage and are difficult to reproduce. They exhibit customer focus, mission relevance, and vertical integration from research through applications. They are demonstrable by metrics such as level of investment, uniqueness of facilities and expertise, and national impact. The Oak Ridge National Laboratory (ORNL) has identified four core competencies which satisfy the above criteria. Each core competency represents an annual investment of at least $100M and is characterized by an integration of Laboratory technical foundations in physical, chemical, and materials sciences; biological, environmental, and social ...
Molecular simulation aims at simulating particles in interaction, describing a physico-chemical system. When considering Markov Chain Monte Carlo sampling in this context, we often meet the same problem of statistical efficiency as with Molecular Dynamics for the simulation of complex molecules (polymers for example). The search for a correct sampling of the space of possible configurations with respect to the Boltzmann-Gibbs distribution is directly related to the statistical efficiency of such algorithms (i.e. the ability of rapidly providing uncorrelated states covering all the configuration space). We investigated how to improve this efficiency with the help of Artificial Evolution (AE). AE algorithms form a class of stochastic optimization algorithms inspired by Darwinian evolution. Efficiency measures that can be turned into efficiency criteria have been first searched before identifying parameters that could be optimized. Relative ...
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and laser post-ionization secondary neutral mass spectrometry (laser-SNMS) have been used to image and quantify targeted compounds, intrinsic elements and molecules with subcellular resolution in single cells of both cell cultures and tissues. Special preparation procedures for analyzing cell cultures and tissue materials were developed. Cancer cells type MeWo, incubated with boronated compounds, were sandwiched between two substrates, cryofixed, freeze-fractured and freeze-dried. Also, after injection with boronated compounds, different types of mouse tissues were extracted, prepared on a special specimen carrier and plunged with high velocity into LN{sub 2}-cooled propane for cryofixation. After trimming, these tissue blocks were freeze-dried. The measurements of the K/Na ratio demonstrated that for both cell cultures and tissue materials the special preparation techniques used were appropriate for preserving the ...
2-Azido[#alpha#-"3"2P]adenosine diphosphate (2-azido[#alpha#-"3"2P]ADP) has been used to photolabel the ADP/ATP carrier in beef heart mitochondria. In reversible binding assays carried out in the dark, this photoprobe was found to inhibit ADP/ATP transport in beef heart mitochondria and to bind to two types of specific sites of the ADP/ATP carrier characterized by high-affinity binding (K/sub d/ = 20 #mu#M) and low-affinity binding (K/sub d/ = 400 #mu#M). In contrast, it was unable to bind to specific carrier sites in inverted submitochondrial particles. Upon photoirradiation of beef heart mitochondria in the presence of 2-azido[#alpha#-"3"2P]ADP, the ADP/ATP carrier was covalently labeled. After purification, the photolabeled carrier protein was cleaved chemically by acidolysis or cyanogen bromide and enzymatically with the Staphylococcus aureus V8 protease. In the ADP/ATP carrier protein, which is 297 amino acid residues in length, two discrete regions extending ...
Radioactive waste has been stored in large underground storage tanks at the Hanford Site since 1944. Approximately 212 million liters of waste containing approximately 240,000 metric tons of processed chemicals and 177 mega-curies of radionuclides are now stored in 177 tanks. These caustic wastes are in the form of liquids, slurries, saltcakes, and sludge. In 1991, the Tank Waste Remediation System (TWRS) Program was established to manage, retrieve, treat, immobilize, and dispose of these wastes in a safe, environmentally sound, and cost-effective manner. The Department of Energy (DOE) has believes that it is feasible to privatize portions of the TWRS Program. Under the privatization strategy embodied in the Request for Proposal (RFP), DOE will purchase services from a contractor-owned, contractor-operated facility under a fixed-price contract. Phase I of the TWRS privatization strategy is a proof-of-concept/commercial demonstration-scale effort. The objectives of ...
Successful interface engineering requires compositional and electronic material characterization as a prerequisite for understanding and intentionally generating interfaces in photovoltaic devices. The paper gives an overview with several examples, all referring to Cu(In,Ga)(S,Se){sub 2} ('CIGSSe')-based solar cells, with an emphasis on characterization using highly specialized methods, such as elastic recoil detection analysis, X-ray emission spectroscopy and photoelectron spectroscopy using synchrotron and ultraviolet light for excitation, inverse photoemission spectroscopy and Kelvin probe force microscopy. First, the determination of the depth profile of the band gap energy E{sub g} in the absorber layer is demonstrated. The modification of E{sub g} towards both interfaces is discussed in terms of beneficial electronic effects. Next, the interface between absorber and buffer layers with alternative and promising non-toxic materials is considered. Between CIGSSe ...
A guidance document on the instrumentation for monitoring and control of cycle chemistry for the steam-water circuits of fossil-fired and combined-cycle power plants was developed within the IAPWS Power Cycle Chemistry Working Group. This technical guidance document has been authorized by the International Association for the Properties of Water and Steam (IAPWS) at its meeting in Doorwerth, The Netherlands, 6-11 September, 2009, for issue by its Secretariat. The members of the IAPWS are: Britain and Ireland, Canada, the Czech Republic, Denmark, France, Germany, Greece, Japan, Russia, and the United States of America, and the associate members Argentina and Brazil, Italy, and Switzerland. In order to achieve suitable chemical conditions in steam-water circuits it is essential to establish reliable monitoring of key parameters on every plant. This enables the demonstration of operation within cycle chemistry targets, and alerts the operators to the need to take ...
This report provides a chronological history of policies and practices relating to the management of radioactive waste for which the US Atomic Energy Commission and its successor agencies, the Energy Research and Development Administration and the Department of Energy, have been responsible since the enactment of the Atomic Energy Act in 1946. The defense programs and capabilities that the Commission inherited in 1947 are briefly described. The Commission undertook a dramatic expansion nationwide of its physical facilities and program capabilities over the five years beginning in 1947. While the nuclear defense activities continued to be a major portion of the Atomic Energy Commission`s program, there was added in 1955 the Atoms for Peace program that spawned a multiplicity of peaceful use applications for nuclear energy, e.g., the civilian nuclear power program and its associated nuclear fuel cycle; a variety of industrial applications; and medical research, diagnostic, and ...
Thin films (1-10 ?m thickness) of nanocomposites (NC) based on organic coordinated compound (OCC) Eu(TTA)2(Ph3PO)2NO3 (where TTA is thenoyl trifluoroacetonate (C8H5F3O2S), Ph3PO - triphenylphosphine (C6H5PO) and polymer-polyvinylpyrrolidone ((C6H9NO)n) (PVP)) were obtained by chemical methods and with different molar ratios into organic polymer matrix. NC have been characterized by measurements of optical transmission, excitation spectra of photoluminescence (PL) and photoluminescence of NC at different concentrations of Eu(TTA)2(Ph3PO)2NO3 in NC. In the optical transmission of NC, the characteristic parameters of NC such as threshold absorbance, dependence on the concentration of the organic coordinated compound in NC, etc., have been determined The displacement of threshold absorption to infrared is observed with increasing of the concentration of the coordination material in NC. The excitation spectrum of photoluminescence of NC led the range from 200 to 400 nm ...
The wear behaviour of metallic material is influenced by the friction force, which in turn, is governed by the hardness and oxidation kinetics of the mating surface. In view of this, present investigation is undertaken to find the influence of mating surface on the high temperature wear of 253 MA alloy. This alloy is developed for high temperature application. In this work 253 MA alloy is made to slide against two different types of counter face material, namely 100Cr6 steel and PM 1000 alloy, at five different temperatures. 100Cr6 steel gets soften with increase of temperature whereas PM 1000 alloy retains its strength even at high temperature. The friction coefficient and the thickness loss of 253 MA alloy is measured and compared against both variety of mating surfaces as function of temperatures. The morphology of the worn surfaces and the transverse section of the worn surfaces are examined under scanning electron microscope (SEM) to identify the material ...
Untreated landfill leachates and wastes from metal plating and mining operations are sources of environmental contamination by heavy metals. Because of their toxicity and potential for accumulation, the discharge of heavy metals must be controlled. Standard physical and chemical treatments used to remove metals from wastes such as concentration by electro-precipitation, ion exchange, solvent extraction, evaporative recovery, and conventional precipitation, are usually expensive and produce high quantities of sludge. Biosorption is the removal of metals from aqueous solutions by microorganisms. It is called biosorption rather than bioadsorption or bioaccumulation because the mechanisms of removal are not restricted to adsorption or metabolic uptake and so the more general term is preferable and has come to be accepted. In this thesis the focus is one two microorganisms and two metals. However, the possible combinations of conditions such as pH, relative metal ...
The General-Purpose Heat Source (GPHS), an improved radioisotope heat source, employs a unique thermal insulation material, carbon-bonded carbon fiber (CBCF), to protect the fuel capsule and to help achieve the highest possible specific power. The CBCF insulation is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF shapes, both tubes and plates, are formed in a multiple molding facility by vacuum molding a water slurry of the carbonized chopped-rayon fiber (54 wt %) and phenolic resin (46 wt %). The molded shapes are subsequently dried and cured. Final carbonization of the resin is at 1600/sup 0/C. Machining to close tolerances (+-0.08 mm) is accomplished by conventional tooling and fixturing. The resulting material is an excellent lightweight insulation with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W(m.K) in vacuum at 2000/sup 0/C. Several attributes ...
Conventional radiography has been the accepted nondestructive testing (NDT) method used for many years to either ''accent'' or ''reject'' a field weld in the pipeline industry. However, conventional radiography requires the expense of film, developing chemicals, and manpower for film development. It also normally has a delay of 2 hours or more between when the weld was radiographed and when the radiographic film of the weld is available for interpretation. Over the last few years, a newer approach to performing radiographic testing, called ''realtime'' radiography, has been used in several different types of field inspection operations. The realtime radiography system forms the image with optical imaging in lieu of photographic film. Objectives of this project were: (Task 1) Integration of realtime x-ray system components into a realtime-radiographic imaging ...
Red mud is a waste and tail material from primary aluminum production, and is named for its color, coming from its iron oxide content. The quantity of red mud is almost equal to the primary aluminum production and leads to a considerable environmental issue. Red mud of the ETI Seydisehir Aluminum Plant is considered as detrimental waste for storage due to its content of various metal oxides, elements and caustics. This detrimental effect is classified into two groups: first, environmental health and second, the cost of storage. In order to minimize the negative effect of red mud, there have been or are presently many investigations carried out on usage of red mud in building materials. However, no effective way of utilizing red mud has yet been found. In this study domestic red mud was investigated and chemical analyses were performed by EDAX and XRF techniques. Radioactivity of the samples was also measured with gamma spectroscopy. The concentrations of elemental ...
The significant and rapid reduction of greenhouse gas emissions is recognized as necessary to mitigate the potential climate effects from global warming. The postcombustion capture (PCC) and storage of carbon dioxide (CO{sub 2}) produced from the use of fossil fuels for electricity generation is a key technology needed to achieve these reductions. The most mature technology for CO{sub 2} capture is reversible chemical absorption into an aqueous amine solution. In this study the results from measurements of the CO{sub 2} absorption capacity of aqueous amine solutions for 76 different amines are presented. Measurements were made using both a novel isothermal gravimetric analysis (IGA) method and a traditional absorption apparatus. Seven amines, consisting of one primary, three secondary, and three tertiary amines, were identified as exhibiting outstanding absorption capacities. Most have a number of structural features in common including steric ...
The study area is located in the Bekaa plain of Lebanon totaling about 12753 ha. It lies between the eastern foothills of Mount Lebanon chain and expands across the Litani River towards the foothills of the eastern Anti-Lebanon Mountains. Its characteristics, i.e. natural terrain, climate and socio-economy, make it vulnerable especially due to soil pollution. This paper tries to identify the nature and level of soil pollution by heavy metals. Valley slopes represent a complex landform and lithology that contributed to the formation of different soil. Agriculture in the plain is being practiced mainly with cash, field crops and vegetables. Throughout the central part of the plain, groundwater table is abundant and relatively high (<1.0 m. locally) that multiplies the vulnerability of the soil-groundwater system. There are different sources of pollution, such as industrial (tanneries, batteries, leather manufacturing), solid and liquid wastes, and agricultural due ...
Focused ion beam (FIB) microscopes have become well-established in the semiconductor industry during the past decade, and are rapidly gaining attention in the field of materials science, both as a tool for producing site specific, parallel sided transmission electron microscope (TEM) specimens and as stand alone specimen preparation and imaging systems. FIB secondary electron imaging (SEI) of nickel-based alloys, such as commercially produced Alloy 600 (approximately Ni 15Cr 10Fe 0.5C), has been demonstrated to show a high degree of sensitivity to the presence of deformation in the alloy, and FIB secondary ion imaging (SII) is particularly useful for identifying the presence of grain boundary corrosion, as secondary ion yields from metallic specimens can increase by three orders of magnitude in the presence of oxygen. This 'oxygen enhanced yield', makes FIB SII ideal for detection of corrosion at grain boundaries down to thicknesses of only a few tens of ...
We previously reported the identification of a new family of plant methyltransferases (MTs), named the SABATH family, that use S-adenosyl-l-methionine (SAM) to methylate a carboxyl moiety or a nitrogen-containing functional group on a diverse array of plant compounds. The Arabidopsis genome alone contains 24 distinct SABATH genes. To identify the catalytic specificities of members of this protein family in Arabidopsis, we screened recombinantly expressed and purified enzymes with a large number of potential substrates. Here, we report that the Arabidopsis thaliana gene At3g44860 encodes a protein with high catalytic specificity towards farnesoic acid (FA). Under steady-state conditions, this farnesoic acid carboxyl methyltransferase (FAMT) exhibits K{sub M} values of 41 and 71 {mu}M for FA and SAM, respectively. A three-dimensional model of FAMT constructed based upon similarity to the experimentally determined structure of Clarkia breweri salicylic acid ...
The vast majority of fundamental studies of metal oxide selective oxidation catalysts have been performed with single phase systems. These investigations established the basic tenents of the redox mechanism of selective oxidation and ammoxidation catalysis. By comparison, structural and kinetic investigations of multiphase oxide catalysts are less numerous because of the inherent difficulties in understanding the relative contributions of separate phases to the catalytic behavior of the composite catalyst. Some attempts have been made in the past to understand the complex chemistry of multiphase catalysts and additional important insights have been realized more recently. However, a clear understanding of the most significant catalytic interactions between individual phases of a multiphase multicomponent redox catalyst is still lacking. In an effort to provide an understanding and a physical basis for the observed synergism in multiphase oxide catalysts, the structural and ...
Humans are exposed to chemicals in contaminated groundwaters that are used as sources of drinking water. Chemicals contaminate groundwater resources as a result of waste disposal methods for toxic chemicals, overuse of agricultural chemicals, and leakage of chemicals into the subsurface from buried tanks used to hold fluid chemicals and fuels. In the process, both the solid portions of the subsurface and the groundwaters that flow through these porous structures have become contaminated. Restoring these aquifers and minimizing human exposure to the parent chemicals and their degradation products will require the identification of suitable biomarkers of human exposure; better understandings of how exposure can be related to disease outcome; better understandings of mechanisms of transport of pollutants in the heterogeneous structures of the ...
Production treatment chemicals represent a diverse collection of chemical classes, added at various points from the wellhead to the final flotation cell, to prevent operational upsets and enhance the separation of oil from water. Information in the literature indicates that while many treatment chemicals are thought to partition into oil and not into the produced water, there are cases where a sufficiently water soluble treatment chemical is added at high enough concentrations to suggest that the treatment chemical may add to the aquatic toxicity of the produced water. A study was conducted to evaluate the potential effect of production treatment chemicals on the toxicity of produced waters using the US EPA Seven-day Mysidopsis bahia Survival, Growth and Fecundity Test. Samples of produced water were collected and tested for toxicity from three platforms under ...
Several works about annual meeting of the Brazilian Chemical Society are present.The search for medicinal chemistry, natural products, biological chemistry, and organic chemistry are shown. Conventional methods and some techniques are discussed and developments of new methods of determining are studied. The use of new chemical compounds, materials, structures and chemical analysis are shown.
Transformation of row material to the consumption goods proceeds by the succession of various technologies using energy and chemicals. Relative contribution of both factors is broadly varied. The chemical reagents are not per se consumption goods and their production is auxiliary. Maximal usage of chemicals is observed in conventional technologies. On the contrary radiation technology does not need chemicals. Therefore usage of radiation technology leads to diminution of chemical processing and hence to the attenuation of the technological press on the environment. As examples the radiation technological methods in conversion of coal and biomass are considered. (author).
In the United States, estimates show that more than 30,000 hazardous waste disposal sites exist, not including military installations, U.S. Department of Energy nuclear facilities, and hundreds and thousands of underground fuel storage tanks; these sites undoubtedly have their own respective hazardous waste chemical problems. When so many sites contain hazardous chemicals, how does one study the health effects of the chemicals at these sites? There could be many different answers, but none would be perfect. For an area as complex and difficult as the study of chemical mixtures associated with hazardous waste disposal sites, there are no perfect approaches and protocols. Human exposure to chemicals, be it environmental or occupational, is rarely, if ever, limited to a single chemical. Therefore, it is essential that we consider multiple ...
Given that fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this study, ALSTOM Power Inc. (ALSTOM) has investigated several coal fired power plant configurations designed to capture CO{sub 2} from effluent gas streams for use or sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be ...
When Congress passed the Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA), it created a number of new reporting requirements for companies that handle toxic chemicals and products containing toxic chemicals. Section 313 of EPCRA requires that certain manufacturers report annual releases to the environment of listed toxic chemicals and chemical categories. Because these manufacturers must know the toxic chemical composition of the products they use to be able to calculate releases accurately, EPA requires some suppliers of mixtures or trade name products containing one or more of the listed section 313 toxic chemicals to notify their customers. The pamphlet explains which suppliers must notify their customers, who must be notified, what form the notice must take, and when it must be sent.
Summary Although risk assessments are typically conducted on a chemical-by-chemical basis, the 1996 Food Quality Protection Act required the US Environmental Protection Agency to consider cumulative risk of chemicals that act via a common mechanism of toxicity. To this end, we are conducting studies with mixtures of chemicals to elucidate mechanisms of joint action at the systemic level with the goal of providing a framework for assessing the cumulative effects of reproductive toxicants. Previous mixture studies conducted with antiandrogenic chemicals are reviewed briefly and two new studies are described. In all binary mixture studies, rats were dosed during pregnancy with chemicals, singly or in pairs, at dosage levels equivalent to approximately one-half of the ED50 for hypospadias or e...
The goal of this program was to increase the high-temperature strength of the H-Series of cast austenitic stainless steels by 50% and upper use temperature by 86 to 140 F (30 to 60 C). Meeting this goal is expected to result in energy savings of 38 trillion Btu/year by 2020 and energy cost savings of $185 million/year. The higher strength H-Series of cast stainless steels (HK and HP type) have applications for the production of ethylene in the chemical industry, for radiant burner tubes and transfer rolls for secondary processing of steel in the steel industry, and for many applications in the heat-treating industry. The project was led by Duraloy Technologies, Inc. with research participation by the Oak Ridge National Laboratory (ORNL) and industrial participation by a diverse group of companies. Energy Industries of Ohio (EIO) was also a partner in this project. Each team partner had well-defined roles. Duraloy Technologies led the team by ...
Previous studies have been conducted in gene expression profiling to identify groups of genes that characterize the colorectal carcinoma disease. Despite the success of previous attempts to identify...Full Text Available
Motivation: The identification of gene regulatory modules is an important yet challenging problem in computational biology. While many computational methods have been proposed to identify...Full Text Available
This plan details the methods and procedures necessary to ensure a safe transition in the operation of the Light Duty Utility Arm (LDUA) System. The steps identified here outline the work scope and identify responsibilities to complete startup, and turnover of the LDUA to Characterization Project Operations (CPO).
While genomic alterations identified in human tumors using techniques such as comparative genomic hybridisation (CGH) may be recurrent, they frequently encompass large regions, in some cases...Full Text Available
The development of a computational intelligent tools based on neural network to identify commercial losses or fraud (theft energy), considering information from a database electric utility, is presented.
A method to identify hadronic molecules in the particle spectrum is reviewed and the conditions for its applicability discussed. Special emphasis is put on the discussion of molecule candidates in the baryon spectrum. (orig.)
Descriptive assessment methods have been used in applied settings to identify consequences for problem behavior, thereby aiding in the design of effective treatment programs. Consensus has not been...Full Text Available
Cancers are highly heterogeneous and contain many passenger and driver mutations. To functionally identify tumor suppressor genes relevant to human cancer, we compiled pools of short harpin...Full Text Available
Large-scale cancer genome projects will soon be able to sequence many cancer genomes to comprehensively identify genetic changes in human cancer. Genome-wide association studies have also identified...Full Text Available
...dates of the implementation of the standard unique health identifier for health care providers. 162.404 Section 162.404 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES ADMINISTRATIVE DATA...
digital libraries, which was identified as a national challenge in the Information ... The linkages between the many digital libraries and information services are ...
Treatment chemicals are used in all facets of the natural gas industry (NGI) from well development through transmission and storage of natural gas. The multitude of chemicals used, combined with the dozens of chemical manufacturers and/or suppliers has lead to the availability of hundreds of possible chemical products. Because of the widespread use of chemical products and their numerous sources, the NGI needs access to consistent data regarding their effectiveness and potential environmental impacts. The objective of this work was to evaluate the effectiveness and potential environmental impacts of, chemical products used in the NGI. This assessment was initially focused on biocides and corrosion inhibitors and their use in the gas production, storage and transmission facilities, The overall approach was obtain the necessary data on ...
This paper very briefly outlines hazardous waste management issues, including regulations, in Mongolia. Air, water, and soil pollutants are identified and placed in context with climatic, social, and economic circumstances. The primary need identified is technology for the collection and disposal of solid wastes. Municipal waste problems include rapid urbanization and lack of sanitary landfills. Industrial wastes of concern are identified from the mining and leather industries. 4 refs., 2 tabs.
Biodiesel is produced from vegetable oils that have been chemically modified by esterification; an example is rapeseed oil methyl ester (RME), made by treating rapeseed oil with methanol. Biodiesel can be burned directly in diesel engines. Oil from the rapeseed variety known as 00 was the first type of vegetable oil used for transesterification to produce biodiesel. Many other oils have been used successfully as biodiesel feedstock including sunflower oil in Southern France and Italy, soybean oil in the USA, and palm oil in Malaysia. Biodiesel can be made from a wide range of feedstock and multi-feedstock blends. Compared to conventional diesel biodiesel has some environmentally friendly advantages, e.g. biodiesel is reported to release fewer solid particles. Potentially even more important is the low level of carbon dioxide generation associated with biodiesel, at a time when CO{sub 2} emissions are falling in every industrial sector except transport. Life-cycle ...
Several examples of agonist-directed trafficking of receptor signalling at 5-HT2A and 5-HT2C receptors have been reported that involve independent downstream transduction pathways. We now report the functional selectivity of a series of chemically diverse agonists at human (h)5-HT2A, h5-HT2B and h5-HT2C-VSV by examining two related responses, the upstream activation of Gq/11 proteins in comparison with its associated cascade of calcium mobilisation. At the h5-HT2A receptor, d-lysergic acid diethylamide (LSD) and the antiparkinsonian agents lisuride, bromocriptine and pergolide exhibit a higher potency for Gq/11 activation than calcium release in contrast with all the other tested ligands such as 5-HT, mCPP and BW723C86, that show an opposite preference of signalling pathway. Comparable observations are made at h5-HT2B and h5-HT2C-VSV receptors, suggesting a similar mechanism of functional selectivity for the three serotonin receptors. Interestingly, the ...
This book examines some of the basic principles behind chemical reaction kinetics. Topics considered include the classical trajectory approach to reactive scattering; periodic orbits and theory of reactive scattering; and semiclassical reactive scattering.
The Bureau of Mines performed chemical research to elaborate details of sulfur chemistry pertaining to the citrate flue gas desulfurization process in which sulfur dioxide (SO2), absorbed (as bisulfite ion) in a buffered sodium citrate solution, is reduce...
This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division (CTD) at Oak Ridge National Laboratory (ORNL) during the period January--March 1997. Created in March 1997 when the CTD Chemical Development and Energy Research sections were combined, the Chemical and Energy Research Section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within seven major areas of research: Hot Cell Operations, Process Chemistry and Thermodynamics, Molten Salt Reactor Experiment (MSRE) Remediation Studies, Chemistry Research, Separations and Materials Synthesis, Solution ...
The lung has the potential of metabolizing many foreign chemicals to a vast array of metabolites with different pharmacological and toxicological properties. Because many chemicals require metabolic...Full Text Available
Regulatory agencies currently rely on rodent carcinogenicity bioassay data to predict whether or not a given chemical poses a carcinogenic threat to humans. We argue that it is always more useful to...Full Text Available
Ion-channels can be activated (gated) by a variety of stimuli including chemicals, voltage, mechanical force or temperature. Whereas molecular mechanisms of ion-channel gating by chemicals and...Full Text Available
This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifi...
The aim of this paper is to obtain the effective potential of the non-topological soliton model at finite temperature with the assumption that the chemical potential {mu} of the system is different from zero and to analyse how the effective potential is influenced by changes in the chemical potential and temperature. (author)
The effect of the water-chemical regime (WCR) on damage sustained by heating surfaces of steam generators at NPP is analyzed. It is indicated that phosphate treatment with minimal excesses of phosphates in the steamgenerator water is the most optimal method of managing the WCR regime of horizontal steam generators.
Importance of the fieldThe cytochrome P450 (CYP) isoforms that are selectively induced following exposure to structurally-diverse chemicals often are the ones capable...Full Text Available
A workshop on alternative toxicological testing methodologies was convened by the Scientific Group on Methodologies for the Safety Evaluation of Chemicals (SGOMSEC) 26-31 January 1997 in Ispra, Italy,...Full Text Available
The reactive airways dysfunction syndrome (RADS), the reactive upper airways dysfunction syndrome (RUDS), the sick building syndrome (SBS), and the multiple chemical sensitivity syndrome (MCS) are overlapping...Full Text Available
The mechanism by which mechanical force regulates the kinetics of a chemical reaction is unknown. Here, we use single-molecule force–clamp spectroscopy and protein engineering to study the effect...Full Text Available
The binding of amphiphilic molecules to lipid bilayers is followed by 19F NMR using chemical shift and line shape differences between the solution and membrane-tethered states of...Full Text Available
Mineral scale formation in water distribution piping impedes flow, resulting in pressure and volume reduction and increasing operational costs. Chemical cleaning is both costly and time consuming, and there are health concerns when chemically cleaning pot...
Thirty-seven papers were presented at this conference in five sessions. Topics covered include regulation, control and consequences of decontamination; decontamination of components and facilities; chemical and non-chemical methods of decontamination; and TMI decontamination experience.
Lipopolysaccharides from different bacteria isolated from cotton were purified and chemically analyzed. Their pulmonary toxicity to animals was tested in inhalation tests. Lipopolysaccharides from Agrobacterium...Full Text Available
K_#beta#/ K_#alpha# x-ray intensity ratio of chromium were measured in different chromium compounds. The results show the variation of the intensity ratio as a function of the chemical environment around the metal ion. (author)
The administration of chemicals at the maximum tolerated dose (MTD) in standard animal cancer tests is postulated to increase cell division (mitogenesis), which in turn increases rates of mutagenesis...Full Text Available
Initial results obtained with a Monte Carlo computer program designed to link initial physical events in irradiated liquid water with subsequent chemical and biological events are presented. 10 refs., 4 figs., 3 tabs.
This project addresses the problem of flue gas desulfurization (FGD) sludge disposal to land. Specifically, the chemical species of FGD sludge constituents are thermodynamically modeled using the equilibrium constant approach, in an attempt to predict the constituent concentratio...
Two additional hyperfine components of the interstellar radical C3H were detected. In addition, methanol was discovered in interstellar clouds. The abundance of HCCN and various chemical isomers in molecular clouds was investigated.
The report gives results of an examination, including mutagenic screening, of the chemical composition of residual fuel oils and their column chromatography pre-fractions. A degree of correlation between composition and mutagenicity has been achieved. Radionuclide data has been o...
Model systems to study the effects of chemicals of environmental concern on bacterial and parasitic diseases as well as the immunosurveillance and destruction of transplantable tumor cells were described...Full Text Available
It is well established that changes to the chemical environment can impair development, physiology and reproductive biology; by contrast, impacts on communication have not been widely reported. This...Full Text Available
Methods of acidizing a subterranean well formation, acidizing compositions, and sequestering additives for preventing the precipitation of metal compounds in the formation are described. Use of the methods and chemicals described should lead to improved formation permeability as compared to use of previous methods and chemicals. 12 claims.
There is increasing concern for the potential adverse health effects of human exposures to chemical mixtures. To better understand the complex interactions of chemicals within a mixture, it is essential...Full Text Available
For better understanding and proper use of organic chemicals addition data are needed, including kinetic data on the scavenging reactions in actual cycles, data on ambient temperature stability and decomposition, sampling and analsyis information, data on effects in a case of fire, and more corrosion data. Use of these chemicals for layup of boilers and other equipment needs to be evaluated for each application. After a preliminary evaluation, such as outlined in this report, every new water treatment chemical should be evaluated in at least two month test in actual steam cycle. (orig.).
Atmospheric pressure plasma enhanced chemical vapour deposition system is built. The electrical and optical characteristics of the APPECVD system is given. The system is used to deposit conductive polymers and nano composites onto glass and metal surfaces. The morphological, optical, chemical and electrical characteristics of deposited surfaces are investigated using SEM, AFM four probe deposition purposes. The photovoltaic applications of plasma deposited polymers and nonconsumption are compared with deposited with electrochemical methods show different results. The electrical, chemical and morphological structures of the samples will be given.
Several possibilities of the use of molecular models in quantum-chemical investigations of the structure of defect centers on the surfaces of oxides on nontransition elements have been illustrated. There has been a special discussion of the assumption of the local nature of the chemical interactions in these systems, which underlies such an approach, and of the consequent laws governing the formation of their lattices in the example cases of zeolites, kaolinites, and comparable boron- and aluminum-containing oxides. A quantum-chemical interpretation of the body of experimental data from investigations of the dehydroxylation of H forms of zeolites has been given. The structure of the Lewis acid centers formed as a result, and their chemisorption properties, have been discussed.
The brochure contains information about the Emergency Planning and Community Right-to-Know Act. This law establishes a structure at the state and local levels to assist communities in planning for chemical emergencies and requires facilities to provide information on various chemicals present in the community. The Act requires that this information be made available to the public. One of the requirements concerns the reporting of annual releases of toxic chemicals to the air, water, and land. These provisions are outlined in Section 313 which mandates annual release reporting for over 300 chemicals.
The effects of variable hardness, pH, alkalinity, humics, and suspended clay on the chemical speciation of copper and its toxicity to fathead minnow larvae in Lake Superior water were investigated. Two proposed methods (toxicity factors and chemical speciation) for predicting LC50 values in specific natural waters from laboratory toxicity data and the average site specific values of general water quality parameters were evaluated. The accuracy of the cupric ion-selective electrode in determining CU/sup +2/ activities in ambient and chemically altered Lake Superior water was also determined.
Chemical effects of L X-ray intensity ratios in niobium and molybdenum compounds were studied by electron and proton bombardments. L{sub {gamma}1} X-rays which involve transition of 4d electrons of the valence shell were found to be sensitive to the chemical environment. The L{sub {gamma}1}/L{sub {beta}1} X-ray intensity ratio increased with an increase of the 4d electron occupation of niobium or molybdenum in niobium or molybdenum compounds, showing that the chemical effects can be ascribed to the 4d electron behavior of the metallic atom in its compounds. (orig.).
Chemical effects of L X-ray intensity ratios in niobium and molybdenum compounds were studied by electron and proton bombardments. L_#gamma#_1 X-rays which involve transition of 4d electrons of the valence shell were found to be sensitive to the chemical environment. The L_#gamma#_1/L_#beta#_1 X-ray intensity ratio increased with an increase of the 4d electron occupation of niobium or molybdenum in niobium or molybdenum compounds, showing that the chemical effects can be ascribed to the 4d electron behavior of the metallic atom in its compounds. (orig.).
A historical background is first given in which the role of biomass is described in relation to its competition with fossil biomass for the production of chemicals and energy. Occurrences of reserves from both sources are then compared. Petrochemical and biomass routes are then analyzed in terms of their relative competitive advantages. The oleochemical and biotechnology cases are analyzed in more detail as examples of biomass utilization. Latin American examples of industrial manufacturing of biomass derived chemicals are then provided. Alcochemicals are analyzed in detail as well as essential oils and other chemicals. Finally, references are made to regional Latin American initiatives regarding biomass and the objectives, organization and nature of the initiative are presented.
Development of a Comprehensive Decontamination Database and an Absorption-Electrochemical Metal Surface Decontamination Technique Combining Chemical and Electrochemical Process
The most relevant aspects of research and service experience with environmentally-assisted cracking (EAC) of carbon (C) and low-alloy steels (LAS) in high-temperature (HT) water are reviewed, with special emphasis on the primary pressure boundary components of boiling water reactors (BWRs). The main factors controlling the susceptibility to EAC under light water reactor (LWR) conditions are discussed with respect to crack initiation and crack growth. The adequacy and conservatism of the current BWRVIP-60 stress corrosion cracking (SCC) disposition lines (DLs), ASME III fatigue design curves, and ASME XI reference fatigue crack growth curves, as well as of the GE EAC crack growth model are evaluated in the context of recent research results. The operating experience is summarized and compared to the experimental/mechanistic background knowledge. Finally, open questions and possible topics for further research are identified. Laboratory investigations revealed ...
Theoretical thermodynamical calculations for the ZrO/sub 2/- Al/sub 2/O/sub 3/-SiO/sub 2/ system are given to expose the regions of the most chemically stable products of crystallization. It is established that ceramics on the base of mullite with zircon addition and containing the minimum quantity of glass phase should be preferably used in chemical media containing HCl.
This book examines some of the basic principles behind chemical reactions kinetics. Topics considered include ab initio determination of potential energy for chemical reactions; semi-empirical potential energy surfaces; general theory of reactive scattering: different equation approach; and integral equation approach to reactive scattering.
This request is submitted to seek interim approval to operate a Toxic Substances Control Act (TSCA) of 1976 chemical waste landfill for the disposal of polychlorinated biphenyl (PCB) waste. Operation of a chemical waste landfill for disposal of PCB waste ...
Microwaves improve the rate of many chemical reactions either interacting with the solvent, when the reaction is carried out in solution, or with the surface of a solid substrate where a suitable reagent is dispersed (dry chemistry). A few examples of chemical reactions positively affected by microwaves are described: particularly interesting are those concerning polymers and radio-pharmaceuticals.
X-ray scattering methods suitable for the investigation of the morphology and chemical composition of self-organized quantum dots and quantum wires are reviewed. Their application is demonstrated in experimental examples showing that a combination of small angle X-ray scattering with high-resolution X-ray diffraction can reveal both the shape and the chemical composition of the self-organized objects. (author)
Papers presented at a meeting on indoor and outdoor climates on sites polluted with volatile organic chemicals. The papers deal with the subject of evaporation of organic chemicals on the polluted sites in relation to the influence on indoor and outdoor climates. Themes dealt with are diffusion through soils and transport of pollutants from the soil into buildings. (AB).
Occupational and environmental exposure to organic ligands, solvents, fuel hydrocarbons, and polychlorinated biphenyls are linked with increased risk of hematologic malignancies. DOE facilities and waste sites in the U.S. are contaminated with mixtures of potentially hazardous chemicals such as metals, organic ligands, solvents, fuel hydrocarbons, polychlorinated biphenyls and radioactive isotopes. A major goal of this project was to establish linkage between chemical/radiation exposure and induction of genomic damage in target populations with the capability to undergo transformation.
A portable fiber optic detector that senses the presence of specific target chemicals by electrostatically attracting the target chemical to an aromatic compound coating on an optical fiber. Attaching the target chemical to the coated fiber reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.
This book deals specifically with the development of new processes of converting coal into useful chemical feedstocks. The major topic in this volume is the generation of syngas and its catalytic conversion to chemicals via the Fischer-Tropsch synthesis. Describes processes involved in conversion, recent catalytic developments, and the commercially important Sasol process. Also includes chapters on the carbide process and potential of future developments in the field.
Chemical influences on the relative Ksub(..beta..)/Ksub(..cap alpha..) x-ray intensity ratio up to five per cent were found for different chemical constitutions of Cr, Mn, Fe and Cu by very precise PIXE measurements. In the discussion of these effects, screening of 3p electrons by a varying 3d valence charge, as well as polarizational effects are of importance.
Chemical influences on the relative Ksub(#nu#)/Ksub(#alpha#) x-ray intensity ratio up to five per cent were found for different chemical constitutions of Cr, Mn, Fe and Cu by very precise PIXE measurements. In the discussion of these effects, screening of 3p electrons by a varying 3d valence charge, as well as polarisational effects are of importance. (author).
DescriptionThis project continues DEFRA's commitment to the International Programme on Chemical Safety, a joint WHO/ILO/UNEP programme. DEFRA's contribution involves preparing Environmental Health Criteira Documents (EHCs), Concise International Chemical Assessments Documents (CICADS) and input to the OECD test Guidelines Programme and gneral risk assessment guidance. Peer reviews of documents prepared through other research in the IPCS network have also been carried out,as well as attending and hosting ta [continued...
Most chemical reactions in industry and biology are catalytic and play a role at some stage of the processing of about 80% of the goods manufactured in the U.S., yet catalysis is a neglected subject in chemical education. This book integrates the fragmentary treatment accorded the topic until now. It covers, in a unified way, catalysis in solutions, by enzymes, in synthetic polymers within the molecular scale cages of zeolites and other molecular sieves, and on surfaces of inorganic solids. The central ideas are chemical; and principles are illustrated by emphasizing industrial reactions and catalysts.
When biomass is used as fuel for thermal conversion plants, minerals from the fuel can be responsible for major problems. Generally, these problems are associated with the existence and development of low melting compounds or eutectics, which form sticky layers. In a fluidised bed, this can result in bed-agglomeration and defluidisation. This causes local high temperature, which often accelerates the process. It ultimately can lead to a completely sintered bed content with a glassy phase gluing the bed particles together and shut-down of the plant. The main objective of the title project is to develop a methodology to predict ash/bed agglomeration and sintering problems, to indicate related problems and, furthermore, to identify solution methods to make different types of biomass streams more viable for energy production. Within the present study, selected fuels are subjected to different existing methods together with some new ones, in order to determine the ...
Radiosensitization by lactate, pyruvate, nalidixic acid and novobiocin was studied in exponentially growing SH-18L human lung fibroblasts. All the chemicals had a slight radiosensitizing effect at a low concentration and a definite effect at a higher one. Decreases in the D_0 and/or Dq values were present in each dose survival curve. Fibroblasts incubated with the low concentration of each chemical for 24 hrs after X irradiation showed no reduction in intracellular ATP content, whereas, the higher concentration produced a significant decrease. These observations suggest that the decrease in the ATP content may be involved in the radiosensitization of human fibroblasts at high concentrations of these chemicals. In contrast, radiosensitization at a low concentration is not explained by a relationship to ATP content. Different mechanisms may be involved in radiosensitization at low and high concentrations of these ...
Many higher plants produce economically important organic compounds such as oils, resins, tannins, natural rubber, gums, waxes, dyes, flavors and fragrances, pharmaceuticals, and pesticides. However, most species of higher plants have never been described, much less surveyed for chemical or biologically active constituents, and new sources of commercially valuable materials remain to be discovered. Advances in biotechnology, particularly methods for culturing plants cells and tissues, should provide new means for the commercial processing of even rare plants and the chemicals they produce. These new technologies will extend and enhance the usefulness of plants as renewable resources of valuable chemicals. In the future, biologically active plant-derived chemicals can be expected to play an increasingly significant role in the commercial development of new products for regulating plant growth and for ...
An analysis system for the long-term mechanical behavior of barrier materials (MACBECE: Mechanical Analysis system considering Chemical transitions of BEntonite-based and CEment-based materials) was developed in order to improve the reliability of the evaluation of the hydraulic field which is one of the important environmental conditions in the safety assessment of the TRU waste disposal. MACBECE is the system that calculates the deformation of barrier materials using their chemical property changes as inputs, and subsequently calculates their hydraulic conductivity taking both their chemical property changes and deformation into consideration. By using MACBECE, the long-term deformation and the transition of hydraulic field for the round-type disposal cavities were evaluated, assuming some sets of chemical evolution data as input. Based on the analysis result, it is considered that the influence of ...
We performed density functional calculations to examine the effects of solvation, hydrogen bonding, backbone conformation, and the side chain on 15N chemical shielding in proteins. We used N-methylacetamide (NMA) and N-formyl-alanyl-X (with X being one of the 19 naturally occurring amino acids excluding proline) as model systems. In addition, calculations were performed for selected fragments from protein GB3. The conducting polarizable continuum model was employed to include the effect of solvent in the density functional calculations. Our calculations for NMA show that the augmentation of the polarizable continuum model with the explicit water molecules in the first solvation shell has a significant influence on isotropic 15N chemical shift but not as much on the chemical shift anisotropy. The difference in the isotropic chemical shift between the standard ?-sheet and ?-helical conformations ranges ...
Current regulations guiding technical aspects of natural resource damage assessments combine source, exposure pathway, resource injury, and monetary damage components. In order to associate any observed injury to the uncontrolled release of chemicals (e.g. oil spills, contaminated sediments, in-place toxics, etc.), it is important to link the chemical ''release'' to the injured resource. In complex environmental settings where multiple sources of similar chemicals are combined, multicomponent chemical methods must be used to link the release to the environmental distribution of chemicals. Three examples of the utility of multicomponent organic chemical analyses linked to comprehensive and representative sampling strategies will be discussed--the Shell Martinez Refinery oil spill, the Exxon Valdez oil spill, and a contaminated sediment assessment. These ...
This report describes an improved method of remotely identifying irradiated nuclear fuel assemblies. The method uses existing in-cell TV cameras to input an image of the notch-coded top of the fuel assemblies into a computer vision system, which then produces the identifying number for that assembly. This system replaces systems that use either a mechanical mechanism to feel the notches or use human operators to locate notches visually. The system was developed for identifying fuel assemblies from the Fast Flux Test Facility (FFTF) and the Clinch River Breeder Reactor, but could be used for other reactor assembly identification, as appropriate.
A primary goal of noninvasive studies of human vision is to identify and characterize multiple visual areas in the human brain analogous to those identified in studies of nonhuman primates. By combining functional MEG measurements with images of individual anatomy derived from MRI, the authors hope to determine the location and arrangement of multiple visual areas in human cortex and to probe their functional significance. The authors have identified several different visual areas thus far which appear to be topographically organized. This paper focuses on the retinotopic characterization of the primary visual area (V1) in humans.
Timber Compartment Boundary This data set identifies the 90 timber compartment boundaries in a 200 square-mile study ... Kawishiwi Ranger Districts, Superior National ...
Recessive mutations of the early phase change (epc) gene in maize affect several aspects of plant development. These mutations were identified initially because of...Full Text Available
Though notes in electronic medical record systems (EMRs) have advantages, they are often criticized for their unattractive and unprofessional appearance. We sought to identify notes regarded by physicians...Full Text Available
... that operated in Pakistan, Dubai, and throughout the Middle East ... identifies 'funds' as one of eight major terrorist ... techniques, and procedures (TTP). ...
AbstractObjectiveTo estimate the prevalence and identify the determinants of non-prescription use of antibiotics for children in Mongolia.MethodsA...Full Text Available
BackgroundTo identify the differential tuberculosis (TB) characteristics within the immigrant population with respect to natives in Spain.Methodology/Principal...Full Text Available
This paper first discusses the challenge offered by natural and anthropogenic systems in all of their complexity and then indicates some areas of research in which specific scientific and technological needs are identifiable.
AIM: To analyze the contribution of Orvosi Hetilap (Hungarian Medical Journal) to the field of gastroenterology.METHODS: All issues of the journal between 1857 and 2008 and identified...Full Text Available
... The variogram analysis of the high resolution imagery has shown that although more spatial scales have been identified than from the SPOT image ...
A strain of Pseudomonas syringae was recently identified as the cause of a new foliar blight of impatiens. The bacterium was resistant to copper compounds, which are used on a variety...Full Text Available
To express growth-related changes in physiologic or other functions in forms usable for kinetic modeling, we are interested in identifying regular relationships that take the form of simple mathematical...Full Text Available
PurposeTo identify the extent of persistence (period of time of continuous therapy with the drug prescribed) of glaucoma patients treated with prostaglandins (latanoprost, bimatoprost,...Full Text Available
An almost linear optimization problem of importance in vibration isolation has been identified and algorithms were developed to minimize the forced vibrational response of structural systems. The constraints can be either displacements of accelerations. T...
BackgroundAs long-term nursing home care is likely to increase with the aging of the population, identifying chronic medical conditions is of particular interest. Although need factors...Full Text Available
The general methods used to complete measurements of human exposures are identified and illustrations are provided for the cases of indirect and direct methods used for exposure analysis. The application...Full Text Available
Objectives. The purposes of this study were to test the hypothesis that vaginal douching is linked to bacterial vaginosis in both symptomatic and asymptomatic women and to identify...Full Text Available
The Buried Waste Integrated Demonstration (BWID) is a program of the Department of Energy (DOE) Office of Technology Development whose mission is to evaluate different new and existing technologies and determine how well they address DOE community waste remediation problems. Twenty-three Technical Task Plans (TTPs) have been identified to support this mission during FY-92; 10 of these have identified some support requirements when demonstrations take place. Section 1 of this report describes the tasks supported by BWID, determines if a technical demonstration is proposed, and if so, identifies the support requirements requested by the TTP Principal Investigators. Section 2 of this report is an evaluation identifying facility characteristics of existing Idaho National Engineering Laboratory (INEL) facilities that may be considered for use in BWID technology demonstration activities.
This exploratory research paper investigated the coping strategies of families of hospitalized psychiatric patients and identified their positive and negative coping strategies. In this paper, the coping...Full Text Available
BackgroundA mycovirus previously identified in brown discolored fruiting bodies of the cultivated mushroom Flammulina velutipes was characterized. We tentatively...Full Text Available
This report provides procedures for evaluating metal, consumable, and combustible cartridge cases. It identifies supporting tests, facilities, and equipment required. Subtests include weapon and ammunition preparation, initial inspection, ammunition chara...
Pathways of salicylic acid (SA) biosynthesis and metabolism in tobacco have been recently identified. SA, an endogenous regulator of disease resistance, is a product of phenylpropanoid metabolism formed...Full Text Available
We identify new organelles associated with the vacuolar system in plant cells. These organelles are defined biochemically by their internal content of three integral membrane proteins: a chimeric reporter...Full Text Available
Alpha-toxin, the major cytotoxic agent elaborated by Staphylococcus aureus, was the first bacterial exotoxin to be identified as a pore former. The protein is secreted as a single-chain, water-soluble...Full Text Available
...identified as oil when the shipment document accurately describes the material as: aviation fuel, diesel fuel, fuel oil, gasoline, jet fuel, kerosene, motor fuel, or...
Investigations were made on the biodegradability and bacterial toxicity of chemicals. The intention was to obtain data necessary for estimating and judging the behaviour of these chemicals during aerobic biological waste water treatment. The course of biodegradation and toxicity with time and concentration could be measured, quantified and described. As test procedure, the respirometric dilution method was used. This method is based on a die away test with continuous measuring of the oxygen used for biochemical oxidation processes. The course of the oxygen demand with time and concentration shows the biodegradation and toxicity patterns of the tested chemical. A variety of household and industrial chemicals were investigated. One group of substances were microbiocides, some of which showed toxic effects at concentrations less than 20 mg/l while others were biodegradable even at concentrations of 200 ...
In this work we present an ultra-low temperature method for the oxidation of an amorphous silicon-carbide-nitride (SiCN) material. The SiCN is deposited on silicon substrates by plasma enhanced chemical vapor deposition using CH{sub 4}, SiH{sub 4}, and N{sub 2} chemistry. The physical and chemical properties are characterized for the as-deposited SiCN and post-oxidized films are discussed. The SiCN film is exposed to oxygen plasma, where it undergoes a chemical transformation into a binary SiO{sub 2} material system. A 1.7 nm/min oxidation rate is typical for this process and compares favorably to oxidation methods utilizing much higher temperatures. The substrate temperature remains extremely low throughout the oxidation process, T{sub s} < 200 deg. C. Changes in film stress, optical constants, film thickness, surface roughness, and film density are measured. Chemical analysis by X-ray ...
Soil gas, soil, and water were assessed for organic and inorganic constituents at the former 19th Street landfill at Fort Gordon, Georgia, from February to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone and flood plain of a creek and soil gas within the estimated boundaries of the former landfill. Soil and water samples were analyzed to evaluate inorganic constituents in soil samples, and organic and inorganic constituents in the surface water of a creek adjacent to the landfill, respectively. This assessment was conducted to provide environmental constituent data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. The passive soil-gas samplers deployed in the water-saturated hyporheic zone and flood plain of the creek adjacent to the former landfill indicated the presence of total petroleum hydrocarbon (TPH) and octane above method detection levels ...
Hydrothermal oxidation (HTO) is a promising technology for the treatment of aqueous-fluid hazardous and mixed waste streams. Waste streams identified as likely candidates for treatment by this technology are primarily aqueous fluids containing hazardous organic compounds, and often containing inorganic compounds including radioisotopes (mixed wastes). These wastes are difficult and expensive to treat by conventional technologies (e.g. incineration) due to their high water content; in addition, incineration can lead to concerns related to stack releases. An especially attractive potential advantage of HTO over conventional treatment methods is the total containment of all reaction products within the overall system. The potential application of hydrothermal oxidation (HTO) technology for the treatment of DOE hazardous or mixed wastes has been uncertain due to concerns about safe and efficient operation of the technology. In principle, aqueous DOE wastes, including ...
Immunoassays are versatile analytical techniques that had a leading role in various clinical applications, during the last four decades. The studies carried out by Rosalyn Yalow, Solomon Berson and Roger Ekins in the 1960s gave a breakthrough in the development of this novel analytical method. Sensitivity up to femtomolar concentrations, high specificity and universal application to different classes of molecular species made immunoassay a very useful tool in analytical investigation. The expertise acquired by immunochemists in producing antibodies against any antigen and the ability of radiochemists in labeling the antigens with "1"2"5I without affecting the active site are the two main factors responsible for the above development. There are concerns about the safety and health of humans due to the high-level contamination of environment by pesticides, industrial compounds and metals, anabolic steroids in milk and meat products, and presence of mycotoxins in food and feed ...
The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead composite material were investigated. The material containing 20-30 vol.% of lead had optimal combination of mechanical and electrochemical properties. Optimal process parameters to manufacture the anodes were identified. ...
Current information on the use of ionizing radiation for improving the storage of subtropical fruits like citrus, grapes, and avocados is reviewed. The feasibility of applying radiation either alone or in combination with other physical or chemical treatments for the control of postharvest fungal diseases is considered. Irradiation effects on the physiology of the fruits as related to respiration, ethylene evolution, changes in major chemical constituents, and quality are discussed. The recent trends in the possible use of irradiation as an alternative treatment to chemical fumigants for disinfestation of citrus and avocados and the prospects for the future application of irradiation for preservation of some of these fruits are outlined. 128 references.
This book provided a set of supplementary papers provided to delegates at the eighth international CANMET/ACI conference on superplasticizers and chemical admixtures in concrete. Recent research on chemical admixtures and superplasticizers was presented along with new approaches to the practical application of concrete admixtures. The presentations highlighted technological advances in the development of superplasticizers and new approaches to the manufacture and implementation of aggregates. Issues regarding the application of plasticizers with various aggregates were addressed, and interactions between cements and superplasticizers were evaluated. Four of the supplementary papers have been catalogued separately for inclusion in this database. refs., tabs., figs.
Biosorption is an important removal mechanism in treating hydrophobic toxic organics in biological reactors. Equilibrium sorption isotherms and sorption kinetics of 2,4-dichlorophenol on live and chemically inactive anaerobic granules were studied. A metabolic inhibitor was used to inactivate the biological activity of the biomass. Results showed that the difference in the biosorption of live and chemically inactive anaerobic granules is not significant. This would suggest that anaerobic biosorption is mainly a physical-chemical process and that metabolic-mediated diffusion in the process is negligible. 12 refs., 3 tabs., 7 figs.
A chemically assisted micro-beam etching system for 3D microanalysis was designed. Using chemically assisted ion beam etching (CAIBE) method with FIB shave-off scanning, about several hundred micrometers clean cross-section will be acquired in a few hours. We use focused ion beam (FIB) and electron beam (EB) as micro-beams, halogen or halide mainly as reactive gases. The apparatus was manufactured based on this concept. We found that the FIB, Q-MS and SED worked as expected. The instrumentation has been completed.
An independent chemical compatibility review of various wrapping and absorbent/padding materials was conducted to evaluate resistance to chemicals and constituents present in liquid waste from the Hanford underground tanks. These materials will be used to wrap long-length contaminated equipment when such equipment is removed from the tanks and prepared for transportation and subsequent disposal or storage. The materials studied were Cooley L18KU, Herculite, and Elephant Mat. The study concludes that these materials are appropriate for use in this application.
... transItion to more capable space-based interceptors as ... ten wtth bmlogtcal, and thirty with chemical weapons. ... are becoming the weapon of choice ...
The Netherlands Chemical Industry Association (VNCI) is investigating the potential for expansion of the CHP capacity in the Dutch chemical industry. This report discusses the return on investment for CHP installations and the market conditions. Moreover, scenario results are presented for the CHP potential and the development of CHP in the chemical industry until 2020. [Dutch] De Vereniging van de Nederlandse Chemische Industrie (VNCI) heeft onderzoek laten uitvoeren om vast te stellen welke economische en beleidsmatige voorwaarden er zijn om het WKK-potentieel in de Nederlandse chemie te realiseren. Dit rapport brengt de marktpositie van WKK en de rentabiliteit van investeringen in WKK in beeld. Verder worden resultaten gegeven voor de potentiele energiebesparing en emissiereductie en wordt een scenario gepresenteerd voor het WKK-potentieel in de chemische industrie tot 2020.
as manufacturing plants and laboratories, including the Chemical Laboratory at the House of David in Benton Harbor, Michigan. Built in America: Historic Building Buildings Survey/...
... Chem. Res., in press, 2006. 8. Smith, BL, Bruno, TJ, Advanced distillation curve measurement with a model predictive temperature controller. Int. ...
The SCF approximation is used in a statistical theory of melting based on equality of the chemical potentials. The results for the melting points of the inert gases are close to the observed values.
The protocols presently established for optimum seed storage do not account for the chemical composition of different seed species, the physiological status of the seed, and the physical status of water...Full Text Available
The molecular structure, chemical properties, and biological function of the xyloglucan polysaccharide isolated from cell walls of suspension-cultured sycamore (Acer pseudoplatanus)...Full Text Available
Hyaluronan (HA), a non-sulfated glycosaminoglycan, is widely used in the clinic for viscosurgery, viscosupplementation, and treatment of osteoarthritis. Four decades of chemical modification...Full Text Available
other chemical applications include use in water softeners, detergents, and food additives. The development of phosphate resources as a leasable commodity provides income to...
... explosive (shotgun shells, etc.) method of forming is being replaced--for the most part--by the electri- cal discharge and magnetic forming methods. ...
Using the radiation chemical method it is possible to prepare wood-plastic composites using doses of 1 to 2.5 kGy. The impregnation mixture in the wood gelatinates and subsequent curing using chemical initiators takes place without outflow of the mixture from the wood and without formation of incrustations. The basic components of the impregnation mixtures used were unsaturated polyester resins; styrene or methyl methacrylate was used as the thinner. The proven initiator of polymerization was 2,2'-azobisisobutyronitrile. The technology is described of wood impregnation and radiation or chemical curing. The effects were monitored of viscosity, temperature, radiation dose and the concentrations of the individual components of the impregnation mixtures and initiators of polymerization on the process of the preparation of wood-plastic composites.
BackgroundBisphenol A (BPA) is a high-production-volume chemical commonly used in the manufacture of polycarbonate plastic. Low-level concentrations of BPA in animals and possibly...Full Text Available
For some neurotoxic chemicals, neurobehavioral effects are now considered to be among the most sensitive end points yet detected, particularly if exposures occur during critical windows of vulnerability....Full Text Available
The OSHA's chemical occupational exposure standard for laboratories is an outgrowth of the previously issued Hazard Communication Standard. The standard relieves laboratories from complying with general industry standards but does not require compliance with specific guidelines. The heart of the standard is the creation of a Chemical Hygiene Plan (CHP) in every laboratory. The CHP addresses major issues such as safety equipment and procedures, work practices and training, the designation of a chemical hygiene officer, and the provision of medical consultation and examination for affected employees. This new standard, in effect as of 31 January, 1991, presents yet another regulatory challenge to laboratory managers but also will ensure a safer work environment for laboratory workers.
NSF-NIST Interaction in Chemistry, Materials Research, Molecular Biosciences, Bioengineering, and ... Laboratory (CSTL). Materials research is centralized in the Materials Science and Engineering ...
Sep 21, 2006 ... NASA has selected Air Products and Chemicals, Inc., Allentown, Pa., to design, furnish and install a plant to produce liquid nitrogen for ...
Vanadium carbide is the most effective grain growth inhibitor for ultrafine WC-Co composites due to its high solubility and mobility in the cobalt phase at relatively low temperatures; however, there are still some debates over the best way to introduce it into the WC-Co formulation. In this paper, the differences between admixed and chemically doped grain growth inhibitors on the microstructural development and properties of an ultrafine WC-10Co composite are discussed. The densification rate of chemically doped samples is slower in the early stage of sintering and the WC grain sizes of the sintered alloys are finer than those of admixed samples, leading to the increase of hardness and transverse rupture strength of the sintered alloys. The effectiveness of the chemically doped inhibitor ...
Immunomodulatory drugs lenalidomide and pomalidomide are synthetic compounds derived by modifying the chemical structure of thalidomide to improve its potency and reduce its side effects. Lenalidomide...Full Text Available
Techniques for culturing, harvesting, and testing bacteria to evaluate bactericidal chemicals for swimming pools are described. Concentrations of 25, 50, and 100 mg of the chlorine stabilizer cyanuric...Full Text Available
Insect growth regulators (IGRs) are a class of new chemicals that interfere with maturation and reproduction in insects. Proposed hypotheses on the biochemical mechanism of action are presented herein....Full Text Available
The electrical responses of the neurons associated with the various types of chemosensory hairs of the blowfly, Phormia regina Meigen, following stimulation by chemical and mechanical...Full Text Available
Existing oil reservoirs might be more fully exploited if the properties of the flow of oil and water in porous media were better known. In laboratory experiments it is important to collect as much information as possible to make a descriptive model of the system, including position imaging and chemical binding information. This thesis develops nuclear methods for obtaining position image and chemical binding information from flow experiments of porous media. A combined positron emission tomography and single photon emission computed tomography system to obtain position images, and a time-differential perturbed angular correlation system to obtain chemical binding information, have been built and thoroughly tested. 68 refs., 123 figs., 14 tabs.
The values of X = 0.77, Z = 0.035, and Y = 0.195 and the stage of evolution of Procyon are determined from the evolutionary tracks and the results of an analysis of the chemical composition of the atmosphere.
The biosynthesis of insect juvenile hormone (JH) and its neuroendocrine control are attractive targets for chemical control of insect pests and vectors of disease. To facilitate the molecular...Full Text Available
The influence of chemical and solvent extraction compatibilising techniques on the mechanical properties of poly-lactic acid (PLA) and MaterBi-polyester (PEM) based bio-composites are compared. First, fibres were chemically grafted with two fatty chains: stearic anhydride and octadecylisocyanate. Grafted fibres were characterised by FTIR and elemental analyses. Contact angle measurements show the hydrophobisation of the fibres in spite of very low surface grafting. Extracted and non-grafted fibres were prepared to be used as references. PEM and PLA-based composites with 30% w/w were prepared by compression moulding. Their mechanical properties were studied. It was found that chemical and solvent treatment of the fibres improved the reinforcement effect in the case of a PEM matrix and the Y...
Tri layer hybrid composites of oil palm empty fruit bunches (EFB) and jute fibres was prepared by keeping oil palm EFB as skin material and jute as the core material and vice versa. The chemical resistance, void content and tensile properties of oil palm EFB/Jute composites was investigated with reference to the relative weight of oil palm EFB/Jute, i.e. 4:1, the fibre loading was optimized and different layering pattern were investigated. It is found from the chemical resistance test that all the composites are resistant to various chemicals. It was observed that marked reduction in void content of hybrid composites in different layering pattern. From the different layering pattern, the tensile properties were slightly higher for the composite having jute as skin and oil palm EFB as core ...
Chemical characterization of passive films formed on AISI 304 austenitic stainless steel, in a borate/boric acid solution at pH 9.2, under various conditions of potential, temperature, and polarizations time, was made by Auger electron spectroscopy combined with ion sputtering, and x-ray photoelectron spectroscopy (XPS). The depth chemical composition, thickness, and duplex character of the passive layers were determined after processing AES sputter profiles by their quantitative approach based on the sequential layer sputtering model. Moreover, separated contributions of elements in their oxidized and unoxidized state could be disclosed from part to part of the oxide-alloy interface. The XPS study specified the chemical bondings which take placed inside the film, between Fe and oxygen (and water).
ABSTRACT We present evidence that differences in soil seedbank persistence among pioneer plants in the cloud forest of Monteverde, Costa Rica, are influenced by differences in seed chemical defense. We used extracted seed chemicals from Bocconia frutescens (Papaveraceae), Guettarda poasana (Rubiaceae), Phytolacca rivinoides (Phytolaccaceae), Urera elata (Urticaceae), Cecropia polyphlebia (Cecropiaceae), and Witheringia meiantha (Solanaceae) to assess seed chemical defense in two ways: (1) a plant pathogen inhibition assay using Pythium irregulare; and (2) a brine shrimp toxicity assay using Artemia salina. The combined performance of each species in the two assays positively correlated with seedbank persistence. In the pathogen assay, mycelium growth was reduced when Pythium was cultured o...
A brief review of standard big bang nucleosynthesis theory and the related observations of the light element isotopes is presented. Implications of BBN on chemical evolution and constraints on particle properties will also be discussed.
An idea whose time has come takes center stage in London this week when BP Chemicals announces details of a consortium of chemical companies joining it in a new recycling project. In the project, which BP has been working on since 1989, waste plastic will be depolymerized to chemical feedstocks, via technology variously called feedstock or chemical recycling, polymer cracking, or tertiary recycling. BP's effort is one of the first to emerge from the research and pilot-plant stages that are committed to actual feedstock recycling of mixed polyolefins and other plastics. But it is only one of the many industry efforts under way to cope with the job of dealing with postconsumer plastics.
A method and apparatus for determining the condition of tissue or otherwise making chemical identifications includes exposing the sample to a light source, and using a synchronous luminescence system to produce a spectrum that can be analyzed for tissue condition.
Chemically reactive compounds in tissues can be monitored through their products of reaction with biomacromolecules. For the purpose of in vivo dose monitoring, hemoglobin (Hb) has been preferred to...Full Text Available
A phenomenon based model for chlorine dioxide delignification of chemical pulp is introduced. The pulp suspension environment is modeled using the concept of two liquid phases, one inside and the other external to the fiber wall. Physico-chemical processes taking place during delignification are implemented with thermodynamic, mass transfer and reaction kinetic models. A broad library of chemical reactions is introduced. Inclusion of each reaction is justified. The model response is tested against experimental laboratory delignification results (o-delignified birch pulp). The experimental data consists of kappa number, hexenuronic acid, inorganic oxy-chlorine compound, and organochlorine (AOX, OX) measurements at several time points during five delignification experiments. The model predic...
We introduce the notion of watching systems in graphs, which is a generalization of that of identifying codes. We give some basic properties of watching systems, an upper bound on the minimum size of a watching system, and results on the graphs which achieve this bound; we also study the cases of the paths and cycles, and give complexity results.
Defects in mismatch repair genes cause the genetic instability characteristic of hereditary nonpolyposis colorectal cancer and a subset of sporadic colon tumors. The newest member of the mismatch repair gene family, GTBP, has recently been identified as a partial cDNA. Here, we describe the isolation of its 5{prime} terminus, allowing definition of the entire coding region. Several polymorphisms within the 5{prime} end were identified and are presented. 13 refs., 1 fig.
A new study identifies and ranks the 10 security gaps responsible for most outsider attacks on college computer networks. The list is intended to help campus system administrators establish priorities as they work to increase security. One network security expert urges that institutions utilize multiple security layers. (DB)
Twenty-six unclassified Campylobacter-like strains previously isolated from 15 chicken carcasses and caecal contents, together with two more strains isolated from chicken faeces on a different occasion, were identified as Helicobacter pullorum using various phenotypic identification methods. API Campy identification kits and a 16-test identification scheme developed for campylobacters failed to identify these bacteria, or identified them as Campylobacter spp. Eighteen strains (including the two isolated on a different occasion) were chosen for examination using a more comprehensive probabilistic identification scheme. Using this method, 14 of the 18 strains were identified as H. pullorum with ID scores > 95%; two strains were also identified as H. pullorum with lower ID scores. Of the remaining two strains, one was not identified with this scheme and the ...
Laboratory-based surveillance of Lyme disease in Connecticut during 1984 and 1985 identified 3,098 persons with suspected Lyme disease; 1,149 were defined as cases. Lyme disease incidence in Connecticut...Full Text Available
The motivation for this design study has been to identify magnet designs for useful magnetic fusion experiments which minimize capital cost. Some possibly useful novel design features have been identified. 5 refs., 6 figs., 3 tabs.
The objective of this work was to identify methods of improving the performance of gas-fired radiant burners through the use of Continuous Fiber Ceramic Composites (CFCCs). Methods have been identified to improve the price and performance characteristics of the porous surface burner. Results are described.
The water and steam circuits of steam generators in pressurized-water nuclear power plants are described together with the mechanism of denting, and the corrosion of spacer plates that leads to cracks in tubes by constriction. The different chemical specifications applicable to the water of the secondary circuit of the generators in normal operation and on first commissioning are listed. The results obtained and the measurements of chemical values taken in operation on the water in the secondary circuits of steam generators at Fessenheim and Bugey are presented.
The water and steam circuits of steam generators in pressurized-water nuclear power plants are described together with the mechanism of denting, and the corrosion of spacer plates that leads to cracks in tubes by constriction. The different chemical specifications applicable to the water of the secondary circuit of the generators in normal operation and on first commissioning are listed. The results obtained and the measurements of chemical values taken in operation on the water in the secondary circuits of steam generators at Fessenheim and Bugey are presented.
A chemical equilibrium model is used, implemented in a compact FORTRAN package called HITEQ, to investigate possible mineral deposition related to prereinjection treatment of Cerro Prieto brines for silica removal. Large saturation ratios of the treated brines with respect to several minerals are indicated by these computations. As a remedy, an inexpensive CO/sub 2/ removal scheme aimed at inhibiting carbonate mineral precipitation is proposed. This scheme is quantitatively discussed with the aid of HITEQ. It is concluded that the proposed treatment is both technically and economically feasible.
Although silicosis has been studied extensively, the mechanism is still not fully understood. Experiments do provide evidence that the actions of unique properties of silica surface on the cell membrane are the starting point of silicotic processes. This paper summarizes literature on chemical properties of silica surface, and the effect of particle size on silica toxicity. This paper also discusses the ways in which silica dusts are though to interact with the cell membrane, with emphasis on freshness, hydrogen bonding, and free-radical interactions.
This request is submitted to seek interim approval to operate a chemical waste landfill for the disposal of polychlorinated biphenyl (PCB) waste. Interim approval is requested for a period not to exceed 5 years. This request covers only the disposal of sm...
This request is submitted to seek interim approval to operate a chemical waste landfill for the disposal of polychlorinated biphenyl (PCB) wastes. This request covers only the disposal of small quantities of solid PCB wastes contained in decommissioned su...
Some aspects of molecular mechanisms common to radiation and chemical carcinogenesis are discussed, particularly the DNA damage done by these agents. Emphasis is placed on epidemiological considerations and on dose-response models used in risk assessment to extrapolate from experimental data obtained at high doses to the effects from long-term, low-level exposures. 3 references, 6 figures. (ACR)
Improved boundary conditions for the cultivation and utilization of renewable feedstocks in Europe as well as advances in the manufacture and use of intermediate products, special and fine chemicals, and new materials on this basis were the topics of a second symposium, organized this time by Hoechst AG, together with the federal ministry of food, agriculture and forestry, in Frankfurt-Hoechst on May 5th and 6th. With more than 300 attendants from the sectors politics, farming, industry, science and administration, the meeting again encountered great interest. (orig.).
The method of spectral disentangling has now created the opportunity for studying the chemical composition in previously inaccessible components of binary and multiple stars. This in turn makes it possible to trace their chemical evolution, a vital aspect in understanding the evolution of stellar systems. We review different ways to reconstruct individual spectra from eclipsing and non-eclipsing systems, and then concentrate on some recent applications to detached binaries with high-mass and intermediate-mass stars, and Algol-type mass-transfer systems.
The author is exploring the efficiency of pulsed plasma processing in the removal of nitrogen dioxide, nitrogen oxide, and other pollutants. This process uses an electrical discharge to create chemical radicals from air molecules. These radicals can react with pollutants and form harmless compounds. Additives such as hydrocarbons are also used to improve the efficiency of the removal. The efficient removal of nitrogen dioxide has required the presence of dilute aqueous solution of ammonia.
The mechanism of chemical poisoning of model heterogeneously catalyzed reactions on transition metal surfaces is studied. Clean Mo(001) surfaces were characterized; results suggest a first-layer contraction of 10% of the bulk interlayer spacing. Characterization of clean Co(0001) surfaces is underway. Decomposition of formic acid on Mo(001) surfaces is being studied. (DLC)
Boiling phenomenon is responsible for impurities concentration in the liquid phase and then can involve chemically aggressive conditions. This paper presents the methodology developed by NOVATOME to know the water quality conditions in the boiling zone and under deposits, in order to improve corrosion tests and materials reliability and safety. Calculations show that concentration of chloride and sodium hydroxide for example can reach significant levels which may lead to corrosion risks. (author).
Biological motors generally fall into two categories: (1) those that convert chemical into mechanical energy via hydrolysis of a nucleoside triphosphate, usually adenosine triphosphate, regarded as life's chemical currency of energy and (2) membrane bound motors driven directly by an ion gradient and/or membrane potential. Here we argue that electrostatic interactions play a vital role for both types of motors and, therefore, the tools of physics can greatly contribute to understanding biological motors.
Some of the origins of corrosion encountered in the secondary side of pressurized water reactor steam generators are:-sludge accumulation (a mixture of metal oxides, primarily magnetite and copper) on tube sheet and attack of tube support plates by aggressive impurities leading to denting. Although Electricite de France has not suffered from these problems, it has developed a chemical cleaning process to dissolve corrosion products at both locations. (author).
A method and apparatus is provided for detecting explosives by thermal imaging. The explosive material is subjected to a high energy wave which can be either a sound wave or an electromagnetic wave which will initiate a chemical reaction in the explosive material which chemical reaction will produce heat. The heat is then sensed by a thermal imaging device which will provide a signal to a computing device which will alert a user of the apparatus to the possibility of an explosive device being present.
Several new development trends in the processing of methanol to various chemical products are discussed. The production of acetic acid by carbonylation of methanol will increase. In the future, methanol is expected to represent the raw material in the production of lower alkenes. The synthesis of lower alcohols, of synthetic gas (homologation), and of aromatic hydrocarbons from methanol are in the research stage.
The electrical resistivity at low temperatures (T = 10 to 90 K) of the lithium isotopes /sup 6/Li and /sup 7/Li and of an isotopic mixture /sup 7 +6/Li has been studied. The specimens contained a small amount of chemical impurities. An appreciable difference was observed in the temperature dependence of the resistivity produced both by deformation of the phonon spectrum, related to the change in isotopic composition, and by the presence of chemical impurities making the nonequilibrium part of the electron distribution function more isotropic.
Biased above threshold (VT), pulsed photocurrent (u) measurements on windowed silicon Pd gate MOS capacitors are shifted (DV) negatively by H2/N2, whereas Au gates shift positively under NO2/air. Below VT, the shifts are reversed by adjustments of interface state population. Minor temperature increases may coax the device from inversion to depletion, inducing sign reversal of the chemical response.
The 1.7 billion pounds of benzene produced each year in the US provide one measure of its utility. At the same time, there are a number of environmental reasons for avoiding the use of benzene in chemical manufacture. Perhaps most compelling: benzene is a potent carcinogen. Scrutiny of many of the chemicals derived from benzene reveals that each molecule contains at least one oxygen atom while benzene completely lacks oxygen atoms. Introduction of oxygen to make up for this lack can require processes that are environmentally problematic. One of the steps used to introduce oxygen atoms during manufacture of adipic acid, a component of Nylon 66, is responsible for 10% of the annual global increase in atmospheric nitrous oxide. This by-product is a causative agent of atmospheric ozone depletion and has been implicated in global warming. With support from EPA and the National Science Foundation, alternative manufacturing processes are being ...
We report on the fouling of Focused Ion Beam (FIB)-fabricated silicon oxide nanopores after exposure to tap water for two weeks. Pore clogging was monitored by Scanning Electron Microscopy (SEM) on both bare silicon oxide and chemically functionalized nanopores. While fouling occurred on hydrophilic silicon oxide pore walls, the hydrophobic nature of alkane chains prevented clogging on the chemically functionalized pore walls. These results have implications for nanopore sensing platform design.
An apparatus for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy.
Compared to yeast esterase, fungal cutinase degraded butyl benzyl phthalate (BBP) far more efficiently; i.e., almost 60% of the BBP disappeared within 7.5 h. Also, the final chemical composition significantly...Full Text Available
DescriptionAs part of a wider effort to develop new approaches to evaluating and quantifying the benefits of chemicals regulation, this project will review the effectiveness of existing information provision tools (such as classification and labelling for hazardous properties) in terms of affecting user behaviour. As some EC legislation relating to regulation of chemicals has been in place for some time, an assumption is made that the information provided by it is leading to an improvement in the way chem [continued...
Physico-chemical studies were carried out on a sample of red mud collected from NALCO, Orissa, after calcination up to 1,200 C at an interval of 100 C. The observed change in properties like surface area, particle size, bulk density and mineral phases etc., can be profitably used while finding an appropriate application of this polluting waste from alumina plants.
A preliminary study of two different kinds of solar receivers (a rotating cavity receiver and a volumetric receiver) suitable to operate in the 1 kW solar facility at the University of Rome is presented. Possible applications of solar energy in the aluminum extraction from leucite and chemical storage by the CuO/Cu[sub 2]O cycle are presented and discussed. (author).
The report gives results of economic evaluations of two processes: the Rockwell International aqueous carbonate process (ACP) and the Wellman-Lord process, the latter applied to a sulfuric acid plant, the Foster Wheeler Resox process, and the Allied Chemical coal reduction proces...
Mutagenic, reproductive, and toxicity effects of two closely related chemicals, ethylnitrosourea (ENU) and methylnitrosourea (MNU), were compared at equimolar and near-equimolar doses in the...Full Text Available
The low potency of many man-made estrogenic chemicals, so-called xenoestrogens, has been used to suggest that risks arising from exposure to individual chemicals are negligible. Another argument used...Full Text Available
The biological activity of coir fibre, coir ash and their components were investigated in vitro by measuring the haemolytic activity and macrophage cytotoxicity. In vivo studies carried out by injecting guinea pigs intratracheally with coir fibres resulted in resolving granulomas. The observed haemolytic activity and macrophage cytotoxicity was more marked with coir ash compared with coir fibres. Chemical analysis of coir ash revealed the presence of toxic chemical constituents in appreciable amounts. PMID:6283694
A method for the chemical modification of the initial structure of humic acids by acylation with indole-3-acetic acid chloride was developed to increase the biological activity of preparations based on peat and lignite humic acids. The plant growth stimulating effect and the antibacterial activity of the synthesized humic preparations were studied.
Chemical effects on the intensity ratio of LX-ray of molybdenum compounds irradiated by 11-keV electrons and by 3-MeV protons were studied using an x-ray crystal spectrometer. It was found that the intensity ratios of L_#gamma#_1/L_#beta#_1 markedly decrease with the increase of ionicity of molybdenum compounds, except for the case of metallic molybdenum. (author).
Contents include: introduction; river systems; physical processes; chemical processes; estuaries and coastal zone; introduction; physical processes; chemical processes; the role of sediments; introduction; the anoxic layer; major-element chemistry; minor-element chemistry; the oxic-anoxic interface; assessment; introduction; analysis of sediments; modelling.
The goal of the invention is to increase the effectiveness of the isolation process through increasing the waterproofing of the stratum. The cited goal is achieved by isolating water influx into a well through introduction of a chemical reagent into the stratum. To interact with the stratum, an alloy of titanium and iron is introduced into the stratum as the chemical reagent with subsequent pumping of hydrogen into the stratum at 100 to 200C.
Understanding risks from exposures to carcinogens and other chemicals depends upon measurement of their dose to target tissues and their reactivity with critical macromolecules. The authors have used AMS detection of radio-isotopes to assess doses and reactivities at low, environmentally relevant doses. Several biomedical investigations show the effectiveness of quantification of biologically important events at extremely high sensitivity with AMS. Specifically, they have measured the addition of environmental carcinogens such as 2-amino-3,8-dimethylimidazo[4,5-f]-quinoaxaline (MelQx), a chemical found in cooked food, to DNA at concentrations relevant to human exposure. Other low level detection problems in biology, such as immunoassay assessment of small environmental chemicals, is being developed with attomole sensitivity. AMS also aids the assessment of genotoxic risks from chemicals by quantifying ...
Government agencies responsible for protecting the public from the adverse effects of toxic chemicals must set priorities for research, regulatory action, protocol testing, and monitoring due to the vast number of toxic chemicals and the limited resources available to these agencies. The National Institute for Occupational Safety and Health (NIOSH) must set priorities for research on hazards encountered in the workplace. Priorities are also utilized by NIOSH in preparing criteria for recommended occupational standards which are forwarded to the Occupational Safety and Health Administration (OSHA), U.S. Department of Labor, for possible promulgation. For various reasons, including rapidly changing conditions in the American workplace, NIOSH has instituted a revised priorities program. In the future, NIOSH research and recommended standards activities will focus not only on individual chemicals, but also on industries, ...
Occupational exposure to N-nitrosamines in the rubber industry was first reported by Fajen et al. (1979). In order to study the origin and formation of nitrosamines in this industry, chemicals and industrial products, as well as the air in various working areas, were analysed. All chemicals used for rubber compounding contain nitrosamines if they are derivatives of secondary amines; e.g., tetramethylthiurame, zinc-diethyldithiocarbamate or N-oxydiethylene benzothiazolylsulfenamide. All rubber products containing these dialkyl amine derivatives exhibited considerable levels of the corresponding nitrosamines. Accordingly, variable concentrations of airborne nitrosamines could be detected at places where rubber products are manufactured or stored. The nitrosamines found correspond to the compounded chemicals. The original nitrosamine level in rubber chemicals is not high enough to explain the amounts found ...
In the present study, models of key chemical processes governing the compositions of the tapped metal from the cupola on the basis of physico-chemical fundamentals have been developed. As evident from the literature survey, the investigations conducted in the past have focused their attention on one phenomenon at a time; for example, a particular chemical reaction, measurement of gas composition or the temperature distribution inside a cupola. Notwithstanding the importance of these studies and their contribution toward the understanding of cupola operation, mathematical models of key chemical processes and their interdependence must be investigated to obtain a complete insight into the various interlinked phenomena occurring inside a cupola. For example, the oxidation of the metallic charge leads to the formation of iron oxide which influences the final content of elements such as silicon, manganese ...
One wonders how a facility will cope with the new Clean Air Act Amendments (CAAA). Environmental engineers working in large companies' facilities and in corporate engineering groups already have an idea of how to comply with the regulations for chemical plant equipment leaks. (In fact, the rules will also affect process bins, wastewater, transfer and storage.) But those who work for smaller companies or who have assignments not directly tied to environmental affairs may not have access to the latest thinking on compliance. One of the first challenges in becoming aware of the CAAA regulations is learning the new language, which consists of acronyms, some containing other acronyms. NESHAP, for example, stands for national emissions standards for hazardous air pollutants. Prior to the CAAA, NESHAPs applied to a few specific chemicals, such as benzene. Now the proposed rules establish a HON, a hazardous organic NESHAP. According to David Gustafson, ...
In May 1990 a group of scientists representing several federal agencies, the International Society of Regulatory Toxicology and Pharmacology, the private sector, and academia met to develop a strategy to encourage the study of the biological effects of low level exposures (BELLE) to chemical agents and radioactivity. A workshop was held in 1991 with seven invited speakers focusing on the toxicological implications of biological adaptations. The selection of topics and speakers was designed to consider critically the concept of hormesis, not only in a broad, conceptual manner, but also at the molecular and biochemical levels. These presentations offered a complementary perspective on the diverse range of molecular mechanisms that can become activated at low levels of toxicant exposure. In addition to chemical toxicology research, an overview of current research on 'Effects of low-dose radiation on the immune response' was presented as well as ...
The application of chemical cleaning for dissolving and removing scale and sludge is being planned in the Japanese pressurized water reactor (PWR) plant in order to maintain high heat transfer performance and to prevent steam generator (SG) tube degradation. In this paper, the effectiveness of the Electric Power Research Institute (EPRI) and German Kraftwerk Union (KWU) processes on the integrity of structural materials other than SG tubes and the comprehensive applicability of chemical cleaning are discussed. The integrity of structural materials such as carbon steel, low-alloy steel and stainless steel was maintained after the EPRI and KWU processes. KWU chemical cleaning tailored for crevice cleaning has been studied to improve its cleaning effectiveness in crevices and to control the corrosion depth of structural materials less than the criterion for corrosion depth. (author)
A survey of wetlands on the Oak Ridge Reservation (ORR) was conducted in 1990. Wetlands occurring on ORR were identified using National Wetlands Inventory (NWI) maps and field surveys. More than 120 sites were visited and 90 wetlands were identified. Wetland types on ORR included emergent communities in shallow embayments on reservoirs, emergent and aquatic communities in ponds, forested wetland on low ground along major creeks, and wet meadows and marshes associated with streams and seeps. Vascular plant species occurring on sites visited were inventoried, and 57 species were added to the checklist of vascular plants on ORR. Three species listed as rare in Tennessee were discovered on ORR during the wetlands survey. The survey provided an intensive ground truth of the wetlands identified by NWI and offered an indication of wetlands that the NWI remote sensing techniques did not detect.
A survey of wetlands on the Oak Ridge Reservation (ORR) was conducted in 1990. Wetlands occurring on ORR were identified using National Wetlands Inventory (NWI) maps and field surveys. More than 120 sites were visited and 90 wetlands were identified. Wetland types on ORR included emergent communities in shallow embayments on reservoirs, emergent and aquatic communities in ponds, forested wetland on low ground along major creeks, and wet meadows and marshes associated with streams and seeps. Vascular plant species occurring on sites visited were inventoried, and 57 species were added to the checklist of vascular plants on ORR. Three species listed as rare in Tennessee were discovered on ORR during the wetlands survey. The survey provided an intensive ground truth of the wetlands identified by NWI and offered an indication of wetlands that the NWI remote sensing techniques did not detect.
The Western Research Institute plan for addressing oil shale plant siting methodology calls for identifying the available resources such as oil shale, water, topography and transportation, and human resources. Restrictions on development are addressed: land ownership, land use, water rights, environment, socioeconomics, culture, health and safety, and other institutional restrictions. Descriptions of the technologies for development of oil shale resources are included. The impacts of oil shale development on the environment, socioeconomic structure, water availability, and other conditions are discussed. Finally, the Western Research Institute plan proposes to integrate these topics to develop a flow chart for oil shale plant siting. Western Research Institute has (1) identified relative topics for shale oil plant siting, (2) surveyed both published and unpublished information, and (3) identified data gaps and research ...
Many existing methods of identifying the optimum sites for installing power system stabilizers (PSSs) in multi-machine systems are restricted to the sequential PSS application, which considers the enhancement of damping of just one critical electromechanical mode at a time; the eigenstructure analysis of the open-loop system, which does not take the control matrix (i.e., the B matrix in the linearized model x = Ax + Bu for power systems) into consideration. This paper presents a method of identifying the optimum sites for installing power system stabilizers. The advantages of this method are: it can identify the optimum sites for installing PSSs so that several electrochemical modes are damped out simultaneously; it takes both the eigenstructure of the open-loop system and the control matrix into consideration.
'The overall objective of the basic research grant is to characterize the potential of common hydrocarbon contaminants in ecosystems to act as endocrine disruptors. The three major lines of research include (1) a biotechnology based screening system to identify potential hormone mimics and antagonists; (2) an animal screening system to identify biomarkers of endocrine effects. and (3) a literature review to identify compounds at a variety of DOE sites that need to be examined for endocrine disrupting effects. By relating results obtained from this research project to contamination problems at various DOE sites. CBR will provide data and information on endocrine disrupting contaminants to DOE for consideration in risk analyses for determining clean-up levels and priorities needed at the sites.'
Poaching of wildlife animals for subsistence and commercial purposes has lead to population declines in Africa. In forensic cases, a need exists to identify the species of origin of carcasses, meat or blood. In the study presented here, the mitochondrial COI gene was sequenced to determine the species of unknown samples in three suspect South African forensic wildlife cases. In two cases the unknown samples were identified as originating from domestic cattle (Bos taurus) and in the third case the sample was identified as common reedbuck (Redunca arundinum). This is the first report of the COI sequence of common reedbuck. The study highlights the need for accurate wildlife reference material from each country in order to convict wildlife cases.
Both the KRW fluidized-bed gasifier and the transport gasifier case studies were used for this assessment. The transport technology is a high-velocity circulating fluidized-bed reactor currently under development by The M.W. Kellogg Company. In the earlier assessment, seven design concepts or cases were identified; a process design was developed; major equipment items were identified; estimates of capital cost, operation and maintenance cost, and cost of electricity were developed; reliability was predicted; and development issues were identified for six studies. Three of the most probable cases were further evaluated for a Greenfield assessment in this report to adequately determine all costs independent of facilities at Plant Wansley.
Both the KRW fluidized-bed gasifier and the transport gasifier case studies were used for this assessment. The transport technology is a high-velocity circulating fluidized-bed reactor currently under development by The M.W. Kellogg Company. In the earlier assessment, seven design concepts or cases were identified; a process design was developed; major equipment items were identified; estimates of capital cost, operation and maintenance cost, and cost of electricity were developed; reliability was predicted; and development issues were identified for six studies. Three of the most probable cases were further evaluated for a Greenfield assessment in this report to adequately determine all costs independent of facilities at Plant Wansley.
Raniganj and Jharia regions together have been for long the single largest coal supplier in India, now contributing about a quarter of the total output in the country. Numerous reasons such as improper mining techniques and policy, as well as unauthorized mining caused surface and subsurface coalfires in these areas. These coalfires burn millions of tonnes of valuable coal resources, creating severe environmental problems and posing enormous operational difficulties of mining. After first use of remote sensing as a tool to identify coalfires in 1960s, with the time, the efficiency of remote sensing to identify and monitoring coalfires has been well established by several researchers. With the knowledge of local geological setting and density sliced surface temperature image the spatial dis...
The study reports the identification of different organic acids that are formed during the pyrohydrolysis of mixed carbide of uranium and plutonium using ion chromatography (IC). The identification of organic acids present in the pyrohydrolysis distillate is required to carry out interference free analysis of Cl and F. The study describes three stage isocratic separations with NaOH eluents having concentrations 2 mM, 10 mM and 50 mM respectively in order to separate and identify both aliphatic and aromatic acids. The present investigation identified formic, acetic, propionic, butyric, tartaric and oxalic acids in the distillate, however, aromatic acids could not be identified. (author)
Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of acid mine drainage remediation, mineral deposition, waste disposal sites, hydrothermal convection, contaminant transport, and groundwater quality. Here they present a numerical simulation model, TOUGHREACT, which considers non-isothermal multi-component chemical transport in both liquid and gas phases. A wide range of subsurface thermo-physical-chemical processes is considered. The model can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The model can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions is considered, such as aqueous complexation, gas dissolution/exsolution, cation ...
Chlorine is not just one of many chemical feedstocks which is used in a few definitely harmful products like PVC or CFC but is irrelevant in all other respects. Just the opposite is true: There is hardly any product line of the chemical industry that can do without chlorine, from herbicides and pesticides to dyes, plastics, pharmaceuticals, photographic atricles, and cosmetics. Chlorine is not only a key element of chemical production but also an ubiquitous element of everyday life in civilisation. There are even many who would agree that the volume of chlorine production is an indicator of the competitive strength and national wealth of a modern society. By now, however, it has become evident that the unreflected use of chlorine is no longer ecologically acceptable. The consequences of a chlorine phase-out as compared to the continued chlorine production at the present level were investigated scientifically by a PROGNOS ...
The cold effluents (sanitary waste and decontaminated radioactive water) are flocculated with sodium phosphate and pumped through a trickling filter. The average decontamination obtained is about 86% for alpha emittera and 76% for beta emitters. The cool effluents (activity < 10/sup -3/ mu c/ml) can be treated by several methods. Provisions have been made for two successive chemical flocculations eventually followed by an adsorptlon. The warm waste treatment (activity between 10/sup -3/ and 1 mu c/ml) is still in the experimental stage. The following methods are used: evaporation for some chemically contaminated wastes, browncoal filtration for reactor effluents, and a combination of chemical treatment and browncoal adsorption in other cases. (auth)
A renewed interest in chemical fractionation of soil organic matter (SOM) originates from the premise that it enables to isolate labile SOM from SOM protected through mineral binding and recalcitrant SOM. Both selective removal of labile non-bound SOM through oxidation or hydrolysis as well as selective removal of minerals and attached SOM are often applied. Molecular-level SOM characterization by means of temperature resolved Pyrolysis-Field Ionization Mass Spectroscopy analysis (Py-FIMS) was used here as an approach to obtain insight into the fate of SOM upon wet chemical treatment with regard to composition and thermal stability. The applied sequential chemical treatment with 6% NaOCl and 10% HF yielded similar sizes in stable SOM fractions between sandy semi-native heathland and cultiv...
This paper reports the chemical compositions of chicken-blood stone Ji Xue Shi measured by Proton Induced X-ray Emission (PIXE). The experimental result show that for the red portion of chicken-blood stone, the concentration of Hg is as high as 20 wt%, and the concentration of S can be above 10 wt%. For the non-red portion the main chemical compositions are Al{sub 2}O{sub 3} and SiO{sub 2}. The obtained chemical compositions are close to those of kaolinite for Balin chicken-blood stone, and of pyrophyllite for Changhua chicken-blood stone, respectively. So far many Changhua chicken-blood stones and Balin chicken-blood stones were found in China, the PIXE method can be used to explore the provenance of available chicken-blood stones. (author)
The development of 'Green Chemistry' requires new materials to replace the conventional organic chemistry by biological catalysts, to produce fine chemicals in an environmentally friendly manner. Microbial whole cells can be directly used as biocatalysts, providing a simple and cheap methodology since enzyme isolation and purification are avoided. High-density polyethylene (HDPE) is a very stable polymer though it can be activated by gamma radiation to induce grafting. Glycidyl methacrylate was grafted onto macroporous HDPE and PP in the range of 1-6%, proportional to the initial monomer concentration. Grafted polymers were further chemically modified with ethylenediamine to generate a cationic hydrogel of micron-size thickness onto the internal polymer surfaces. Modified polymers were able to immobilize Gram-positive and Gram-negative bacteria that can catalyze a chemical reaction as efficient as free ...
The population of the hyporheic interstice and moss cushions by meso- and macroinvertebrates as found at the three measuring points along the Alte Riefensbeek and the Grosse Soese, respectively, in the period from March 1987 to May 1988 is studied and evaluated together with chemical measurements performed between 1987 and 1990. The six measuring points are positioned along an acidification gradient ranging from non-acid to severely acidified. Chemical and biological paramerters are studied with regard to their suitability as indicators of acidification. A model is presented which decribes the influence of abiotic anthropogenic and natural factors on invertebrate species diversity and populations and which can serve as a basis for the calculation of critical deposition burdens. (orig.).
To form a licensing basis for a new methodology for a fuel channel safety analysis code for CANDU-6 nuclear reactor, a CATHENA model for a post-blowdown fuel channel analysis has been developed, and tested for a high temperature thermal-chemical experiment CS28-1 [Lei, Q.M., 1993. Post-test analysis of the 28-element high-temperature thermal-chemical experiment CS28-1. In: 4th International Conference on Simulation Methods in Nuclear Engineering, Montreal, PQ, 1993]. Pursuant to the objective of this investigation, the current study has focused on understanding the involved phenomena, their interrelations, and how to maintain a good accuracy of the temperature and H2 generation rate prediction without losing the important physics of the involved phenomena. The transient simulation results ...
The combustin of chloroethane is modeled as a stirred reactor so that we can study critical emission characteristics of the reactor as a function of residence time. We examine important operating conditions such as pressure, temperature, and equivalence ratio and their influence on destructive efficiency of chloroethane and production of other chlorinated products. The model uses a detailed chemical kinetic mechanism that we have developed previously for C{sub 3} hydrocarbons. We have added to this mechanism the chemical kinetic mechanism for C{sub 2} chlorinated hydrocarbons developed by Senkan and coworkers. Some reactions have been added to Senkan's mechanism and some of the reaction-rate expressions have been updated to reflect recent developments in the literature. In the modeling calculations, sensitivity coefficients are determined to find which reaction-rate constants have the largest effect on destructive efficiency. 25 refs., ...
Purpose To study the chemical modifications induced upon irradiation of solid human insulin at radiosterilization doses and investigate the influence of the absorbed dose on radiolysis. Materials and Methods Volatile radiolytic products were monitored by gas chromatography coupled with mass spectrometry (GC-MS) and non-volatile products by two different high performance liquid chromatography (HPLC) methods: the formation of higher molecular weight proteins was assessed by size exclusion liquid chromatography whereas assays for related compounds and chemical potency tests were carried out using reverse-phase HPLC-UV. Conformational changes were investigated by measurements of circular dichroism. Results After gamma irradiation at 10?kGy, the recovery of insulin was 96.8%; higher molecular w...
This current work is concerned with the development of polypropylene composites reinforced with cellulose and cellulignin fibers attained from sugarcane bagasse. Moreover, the fibers were chemically modified by acetylating process and its effects on the fiber/matrix interaction were also evaluated. The chemical modification efficiency was verified by FTIR analysis and the fibers morphological aspects of fibers by SEM. Likewise, the influence of modified fibers content in the composites was studied by mechanical (tensile, shear and flexural tests) and thermal analyses (TGA and DSC). After the chemical modification, the FTIR results showed the appearance of acetyl groups and reduction of OH bonds for all fibers. Together with, SEM characterization showed that the acetylation changed the morp...
We have developed a cell-mediated mutagenesis assay in which cells with the appropriate markers for mutagenesis are co-cultivated with either lethally irradiated rodent embryonic cells that can metabolize carcinogenic hydrocarbons or with primary rat liver cells that can metabolize chemicals carcinogenic to the liver. During co-cultivation, the reactive metabolites of the procarcinogen appear to be transmitted to the mutable cells and induce mutations in them. Assays of this type make it possible to demonstrate a relationship between carcinogenic potency of the chemicals and their ability to induce mutations in mammalian cells. In addition, by simultaneously comparing the frequencies of transformation and mutation induced in normal diploid hamster cells by benzo(a)pyrene (BP) and one of its metabolites, it is possible to estimate the genetic target size for cell transformation in vitro.
A means of determination of a ctive hydrogen of hydroxyl, carboxyl, sulfhydryl, amino, amido and sulfonamido groups by chemical ionization mass spectrometry using ammonia and trideuterioammonia as reagent gases is described. The method is based on exchange of active hydrogen for deuterium occurring during the chemical ionization process using trideuterioammonia, with comparison of m/z for ammonium adduct [M + NH1]+ and trideuterioammonium adduct [M--nH + nD + ND4]+, or of protonated molecular ion [M + H]+ and deuteronated molecular ion [M--nH + nD + D]+ yielding the number of active hydrogens. Applications have been made to several classes of biologically important compounds. PMID:427257