WorldWideScience

Sample records for chemicals

  1. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  2. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  3. Chemical use

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of research and activities related to chemical use on Neal Smith National Wildlife Refuge between 1992 and 2009. The chemicals used on the Refuge...

  4. Chemical sensor

    Science.gov (United States)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  5. Chemical machining

    Directory of Open Access Journals (Sweden)

    A. Yardimeden

    2007-08-01

    Full Text Available Purpose: Nontraditional machining processes are widely used to manufacture geometrically complex and precision parts for aerospace, electronics and automotive industries. There are different geometrically designed parts, such as deep internal cavities, miniaturized microelectronics and fine quality components may only be produced by nontraditional machining processes. This paper is aiming to give details of chemical machining process, industrial applications, applied chemical etchants and machined materials. Advantages and disadvantages of the chemical machining are mentioned.Design/methodology/approach: In this study, chemical machining process was described its importance as nontraditional machining process. The steps of process were discussed in detail. The tolerances of machined parts were examined.Findings: Paper describes the chemical machining process, industrial applications, applied chemical etchants and machined materials.Practical implications: The machining operation should be carried out carefully to produce a desired geometry. Environmental laws have important effects when chemical machining is used.Originality/value: The importance of nontraditional machining processes is very high.

  6. Chemical Leukoderma.

    Science.gov (United States)

    Bonamonte, Domenico; Vestita, Michelangelo; Romita, Paolo; Filoni, Angela; Foti, Caterina; Angelini, Gianni

    2016-01-01

    Chemical leukoderma, often clinically mimicking idiopathic vitiligo and other congenital and acquired hypopigmentation, is an acquired form of cutaneous pigment loss caused by exposure to a variety of chemicals that act through selective melanocytotoxicity. Most of these chemicals are phenols and aromatic or aliphatic catechols derivatives. These chemicals, however, are harmful for melanocytes in individuals with an individual susceptibility. Nowadays, chemical leukoderma is fairly common, caused by common domestic products. The presence of numerous acquired confetti- or pea-sized macules is clinically characteristic of chemical leukoderma, albeit not diagnostic. Other relevant diagnostic elements are a history of repeated exposure to a known or suspected depigmenting agent at the sites of onset and a macules distribution corresponding to sites of chemical exposure. Spontaneous repigmentation has been reported when the causative agent is avoided; the repigmentation process is perifollicular and gradual, taking place for a variable period of weeks to months. PMID:27172302

  7. Chemical networks*

    OpenAIRE

    Thi Wing-Fai

    2015-01-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One o...

  8. Chemical machining

    OpenAIRE

    A. Yardimeden; T. Ozben; O. Cakir

    2007-01-01

    Purpose: Nontraditional machining processes are widely used to manufacture geometrically complex and precision parts for aerospace, electronics and automotive industries. There are different geometrically designed parts, such as deep internal cavities, miniaturized microelectronics and fine quality components may only be produced by nontraditional machining processes. This paper is aiming to give details of chemical machining process, industrial applications, applied chemical etchants and mac...

  9. Chemical Radioprotectors

    Directory of Open Access Journals (Sweden)

    S. N. Upadhyay

    2005-10-01

    Full Text Available Protection of biological systems against radiation damage is of paramount importance during accidental and unavoidable exposure to radiation. Several physico-chemical and biological factors collectively contribute to the damage caused by radiation and are, therefore, targets for developing radioprotectors. Work on the development of chemicals capable of protecting biological systemsfrom radiation damage was initiated nearly six decades ago with cysteine being the first molecule to be reported. Chemicals capable of scavenging free radicals, inducing oxygen depletion,antioxidants and modulators of immune response have been some of the radioprotectors extensively investigated with limited success. Mechanism of action of some chemical radioprotectors and their combinations have been elucidated, while further understanding is required in many instances. The present review elaborates on structure-activity relationship of some of the chemical radioprotectors, their evaluation, and assessment, limitation, and future prospects.

  10. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  11. Chemical Peels

    Science.gov (United States)

    ... pills, who subsequently become pregnant or have a history of brownish facial discoloration. Scarring Reactivation of cold sores What can I expect after having a chemical peel? All peels require some follow-up care: ...

  12. Unnecessary Chemicals

    Science.gov (United States)

    Johnson, Anita

    1978-01-01

    Discusses the health hazards resulting from chemical additions of many common products such as cough syrups, food dyes, and cosmetics. Steps being taken to protect consumers from these health hazards are included. (MDR)

  13. Chemical kinetics

    International Nuclear Information System (INIS)

    This book gives descriptions of chemical kinetics. It starts summary of chemical kinetics and reaction mechanism, and explains basic velocity law, experiment method for determination of reaction velocity, temperature dependence of reaction velocity, theory of reaction velocity, theory on reaction of unimolecular, process of atom and free radical, reaction in solution, catalysis, photochemical reaction, such as experiment and photochemical law and rapid reaction like flame, beam of molecule and shock tube.

  14. Chemical networks

    Science.gov (United States)

    Thi, Wing-Fai

    2015-09-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One on-going research subject is finding new paths to synthesize species either in the gas-phase or on grain surfaces. Specific formation routes for water or carbon monoxide are discussed in more details. 13th Lecture of the Summer School "Protoplanetary Disks: Theory and Modelling Meet Observations"

  15. Chemical pressure

    OpenAIRE

    Hauser, Andreas; Amstutz, Nahid; Delahaye, Sandra; Sadki, Asmaâ; Schenker, Sabine; Sieber, Regula; Zerara, Mohamed

    2002-01-01

    The physical and photophysical properties of three classic transition metal complexes, namely [Fe(bpy)3]2+, [Ru(bpy)3]2+, and [Co(bpy)3]2+, can be tuned by doping them into a variety of inert crystalline host lattices. The underlying guest-host interactions are discussed in terms of a chemical pressure.

  16. Chemical Peels

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ... Chemical peels public SPOT Skin Cancer™ Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ...

  17. Chemical Mahjong

    Science.gov (United States)

    Cossairt, Travis J.; Grubbs, W. Tandy

    2011-01-01

    An open-access, Web-based mnemonic game is described whereby introductory chemistry knowledge is tested using mahjong solitaire game play. Several tile sets and board layouts are included that are themed upon different chemical topics. Introductory tile sets can be selected that prompt the player to match element names to symbols and metric…

  18. Chemical dispersants

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

    2016-01-01

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil biodeg

  19. Chemical flashlamps

    International Nuclear Information System (INIS)

    The authors have characterized the optical output and Nd:glass pumping performance of large-scale (120-cm-long, 1.2-cm-inner-diam), metal-oxidizer chemical flashlamps supplied to us by G.T.E. Sylvania. The experimental results were obtained on the same test bed that was used to study xenon electrical flashlamps, as described in Dependence of Flashlamp Performance on Gas Fill and Bore Size, earlier in this section. The peak Nd inversion levels produced by the chemical lamps were less than or equal to 10% of those generated by a xenon lamp of similar size and energy loading. The Peak Nd levels are in good agreement with predictions for the pumping rates in Nd:glass by a blackbody at the color temperatures of 30000 to 50000C, which they have measured during the burn of the pyrotechnic lamp

  20. Chemical cosmology

    CERN Document Server

    Boeyens, Jan CA

    2010-01-01

    The composition of the most remote objects brought into view by the Hubble telescope can no longer be reconciled with the nucleogenesis of standard cosmology and the alternative explanation, in terms of the LAMBDA-Cold-Dark-Matter model, has no recognizable chemical basis. A more rational scheme, based on the chemistry and periodicity of atomic matter, opens up an exciting new interpretation of the cosmos in terms of projective geometry and general relativity. The response of atomic structure to environmental pressure predicts non-Doppler cosmical redshifts and equilibrium nucleogenesis by alp

  1. Chemical spectroscopy

    International Nuclear Information System (INIS)

    The purpose of chemical spectroscopy with neutrons is to utilize the dependence of neutron scattering cross-sections on isotope and on momentum transfer (which probes the spatial extent of the excitation) to understand fundamental and applied aspects of the dynamics of molecules and fluids. Chemical spectroscopy is divided into three energy ranges: vibrational spectroscopy, 25-500 MeV, for which much of the work is done on Be-filter analyzer instruments; low energy spectroscopy, less than 25 MeV; and high resolution spectroscopy, less than 1 MeV, which typically is performed on backscattering spectrometers. Representative examples of measurements of the Q-depenence of vibrational spectra, higher energy resolution as well as extension of the Q-range to lower values at high energy transfers, and provisions of higher sensitivities in vibrational spectroscopy are discussed. High resolution, high sensitivity, and polarization analysis studies in low energy spectroscopy are discussed. Applications of very high resolution spectroscopy are also discussed

  2. Chemical sputtering

    International Nuclear Information System (INIS)

    In this thesis, the author focuses on chemical sputtering by keV ions, treating two specific examples: the chemical effects occurring when bombarding simple condensed gases and the mechanisms of the ion-assisted etching process. First, however, the mechanism of sputtering of condensed gases in general is discussed. These mechanisms have been investigated using condensed noble gases as target material. The thesis is a compilation of articles published elsewhere. Contents: sputtering of condensed noble gases by keV heavy ions; surface distribution as an observable factor in the energy distribution of sputtered particles; reactive sputtering of simple condensed gases by keV heavy ion bombardment; mass spectra of nozzle-produced small molecular clusters of H2O, NH3, CO and CH4; mass and energy distribution of particles sputter-etched from Si in a XeF2 environment; argon-ion assisted etching of silicon by molecular chlorine; energy distribution of sputtered poly-atomic molecules. (Auth.)

  3. CHEMICAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Melvin

    1965-06-01

    How did life come to be on the surface of the earth? Darwin himself recognized that his basic idea of evolution by variation and natural selection must be a continuous process extending backward in time through that period in which the first living things arose and into the period of 'Chemical Evolution' which preceded it. We are approaching the examination of these events by two routes. One is to seek for evidence in the ancient rocks of the earth which were laid down prior to that time in which organisms capable of leaving their skeletons in the rocks to be fossilized were in existence. This period is sometime prior to approximately 600 million years ago. The earth is believed to have taken its present form approximately 4700 million years ago. We have found in rocks whose age is about 1000 million years certain organic molecules which are closely related to the green pigment of plants, chlorophyll. This seems to establish that green plants were already fluorishing prior to that time. We have now found in rocks of still greater age, namely, 2500 million years, the same kinds of molecules mentioned above which can be attributed to the presence of living organisms. If these molecules are as old as the rocks, we have thus shortened the time available for the generation of the complex biosynthetic sequences which give rise to these specific hydrocarbons (polyisoprenoids) to less than 2000 million years.

  4. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C.; Huang, Jiang; Heath, James R.; Phelps, Michael E.; Quake, Stephen R.; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  5. Chemical Security Analysis Center

    Data.gov (United States)

    Federal Laboratory Consortium — In 2006, by Presidential Directive, DHS established the Chemical Security Analysis Center (CSAC) to identify and assess chemical threats and vulnerabilities in the...

  6. Design of chemical plant

    International Nuclear Information System (INIS)

    This book describes design of chemical plant, which includes chemical engineer and plan for chemical plant, development of chemical process, cost engineering pattern, design and process development, general plant construction plan, project engineering, foundation for economy on assets and depreciation, estimation for cost on capital investment and manufacturing cost, design with computers optimal design and method like fluid mechanics design chemical device and estimation for cost, such as dispatch of material and device writing on design report and appendixes.

  7. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2012-01-01

    The Advances in Chemical Physics series-the cutting edge of research in chemical physics The Advances in Chemical Physics series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics. This volume explores: Quantum Dynamical Resonances in Ch

  8. Chemical Transformation Simulator

    Science.gov (United States)

    The Chemical Transformation Simulator (CTS) is a web-based, high-throughput screening tool that automates the calculation and collection of physicochemical properties for an organic chemical of interest and its predicted products resulting from transformations in environmental sy...

  9. Chemical Industry Bandwidth Study

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2006-12-01

    The Chemical Bandwidth Study provides a snapshot of potentially recoverable energy losses during chemical manufacturing. The advantage of this study is the use of "exergy" analysis as a tool for pinpointing inefficiencies.

  10. Personal Chemical Exposure informatics

    Science.gov (United States)

    Chemical Exposure science is the study of human contact with chemicals (from manufacturing facilities, everyday products, waste) occurring in their environments and advances knowledge of the mechanisms and dynamics of events that cause or prevent adverse health outcomes. (adapted...

  11. Tobacco and chemicals (image)

    Science.gov (United States)

    Some of the chemicals associated with tobacco smoke include ammonia, carbon dioxide, carbon monoxide, propane, methane, acetone, hydrogen cyanide and various carcinogens. Other chemicals that are associated with chewing ...

  12. Chemical Search Web Utility

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Chemical Search Web Utility is an intuitive web application that allows the public to easily find the chemical that they are interested in using, and which...

  13. Capacitive chemical sensor

    Science.gov (United States)

    Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

    2014-05-27

    A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  14. Chemicals Industry Vision

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1996-12-01

    Chemical industry leaders articulated a long-term vision for the industry, its markets, and its technology in the groundbreaking 1996 document Technology Vision 2020 - The U.S. Chemical Industry. (PDF 310 KB).

  15. Advances in chemical physics

    CERN Document Server

    Prigogine, Ilya

    2009-01-01

    The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.

  16. Models of Chemical Evolution

    OpenAIRE

    Matteucci, Francesca

    2003-01-01

    The basic principles underlying galactic chemical evolution and the most important results of chemical evolution models are discussed. In particular, the chemical evolution of the Milky Way galaxy, for which we possess the majority of observational constraints, is described. Then, it is shown how different star formation histories influence the chemical evolution of galaxies of different morphological type. Finally, the role of abundances and abundance ratios as cosmic clocks is emphasized an...

  17. Chemical evolution and life

    OpenAIRE

    Malaterre Christophe

    2015-01-01

    In research on the origins of life, the concept of “chemical evolution” aims at explaining the transition from non-living matter to living matter. There is however strong disagreement when it comes to defining this concept more precisely, and in particular with reference to a chemical form of Darwinian evolution: for some, chemical evolution is nothing but Darwinian evolution applied to chemical systems before life appeared; yet, for others, it is the type of evolution that happened before na...

  18. Computing Equilibrium Chemical Compositions

    Science.gov (United States)

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

    Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.

  19. What Is Chemical Stoichiometry?

    Science.gov (United States)

    Smith, William R.; Missen, Ronald W.

    1979-01-01

    Chemical stoichiometry is discussed free from kinetic or thermodynamic considerations. The means for determining the following are presented: the number of stoichiometric degrees of freedom, the number of components, a permissible set of chemical equations, and a permissible set of components, for a closed system undergoing chemical reaction.…

  20. Chemical Recycle of Plastics

    Directory of Open Access Journals (Sweden)

    Sara Fatima

    2014-11-01

    Full Text Available Various chemical processes currently prevalent in the chemical industry for plastics recycling have been discussed. Possible future scenarios in chemical recycling have also been discussed. Also analyzed are the effects on the environment, the risks, costs and benefits of PVC recycling. Also listed are the various types of plastics and which plastics are safe to use and which not after rcycle

  1. Equilibrium Chemical Engines

    OpenAIRE

    Shibata, Tatsuo; Sasa, Shin-ichi

    1997-01-01

    An equilibrium reversible cycle with a certain engine to transduce the energy of any chemical reaction into mechanical energy is proposed. The efficiency for chemical energy transduction is also defined so as to be compared with Carnot efficiency. Relevance to the study of protein motors is discussed. KEYWORDS: Chemical thermodynamics, Engine, Efficiency, Molecular machine.

  2. Chemical and Environmental Technology.

    Science.gov (United States)

    Sheather, Harry

    The two-year curriculum in chemical technology presented in the document is designed to prepare high school graduates for technical positions in the chemical industry. Course outlines are given for general chemistry, chemical calculations, quantitative analysis, environmental chemistry, organic chemistry 1 and 2, instrumental analysis, and…

  3. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2012-01-01

    The Advances in Chemical Physics series-the cutting edge of research in chemical physics The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series presents contributions from internationally renowned chemists and serves as the perfect supplement to any advanced graduate class devoted to the study o

  4. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2011-01-01

    The Advances in Chemical Physics series-the cutting edge of research in chemical physics The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series offers contributions from internationally renowned chemists and serves as the perfect supplement to any advanced graduate class devoted to the study of che

  5. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2014-01-01

    Advances in Chemical Physics is the only series of volumes available that explores the cutting edge of research in chemical physics. This is the only series of volumes available that presents the cutting edge of research in chemical physics.Includes contributions from experts in this field of research.Contains a representative cross-section of research that questions established thinking on chemical solutions.Structured with an editorial framework that makes the book an excellent supplement to an advanced graduate class in physical chemistry or chemical physics.

  6. Advances in chemical Physics

    CERN Document Server

    Rice, Stuart A

    2011-01-01

    The Advances in Chemical Physics series-the cutting edge of research in chemical physics The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series offers contributions from internationally renowned chemists and serves as the perfect supplement to any advanced graduate class devoted to the study of che

  7. Development of chemical dosimeters

    International Nuclear Information System (INIS)

    A chemical dosimeter is a system that measures the energy by virtue of chemical changes from ionizing absorbed radiation produced unit when it is exposed to ionizing radiation. In all chemical dosimeters radiation induced chemical reaction produces at least one, initially absent species, which is properties long lived enough to determine its quantity or the change in the initial systems. Different types of chemical dosimeters were discussed such as aqueous, gaseous and solid, but the great consideration was given to aqueous systems because of their vital role in setting many processes.(Author)

  8. Chemical exchange program analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Waffelaert, Pascale

    2007-09-01

    As part of its EMS, Sandia performs an annual environmental aspects/impacts analysis. The purpose of this analysis is to identify the environmental aspects associated with Sandia's activities, products, and services and the potential environmental impacts associated with those aspects. Division and environmental programs established objectives and targets based on the environmental aspects associated with their operations. In 2007 the most significant aspect identified was Hazardous Materials (Use and Storage). The objective for Hazardous Materials (Use and Storage) was to improve chemical handling, storage, and on-site movement of hazardous materials. One of the targets supporting this objective was to develop an effective chemical exchange program, making a business case for it in FY07, and fully implementing a comprehensive chemical exchange program in FY08. A Chemical Exchange Program (CEP) team was formed to implement this target. The team consists of representatives from the Chemical Information System (CIS), Pollution Prevention (P2), the HWMF, Procurement and the Environmental Management System (EMS). The CEP Team performed benchmarking and conducted a life-cycle analysis of the current management of chemicals at SNL/NM and compared it to Chemical Exchange alternatives. Those alternatives are as follows: (1) Revive the 'Virtual' Chemical Exchange Program; (2) Re-implement a 'Physical' Chemical Exchange Program using a Chemical Information System; and (3) Transition to a Chemical Management Services System. The analysis and benchmarking study shows that the present management of chemicals at SNL/NM is significantly disjointed and a life-cycle or 'Cradle-to-Grave' approach to chemical management is needed. This approach must consider the purchasing and maintenance costs as well as the cost of ultimate disposal of the chemicals and materials. A chemical exchange is needed as a mechanism to re-apply chemicals on site. This

  9. Radiolabelling of chemicals

    International Nuclear Information System (INIS)

    Labeling of chemical additives with radioactive isotopes can solve numerous problems in geothermal operations. The physical and chemical behavior of many chemicals slated for geothermal operations can be studied with the required detail at the extremely low concentration of the commercially available (non-labeled) compounds. The problems of labeling and the basics of these radioactively labeled chemicals are described in this report. Conclusions of this study are: (1) chemicals labeled with radioactive isotopes can be used to investigate the chemical and physical behavior of chemical additives used in geothermal operations. The high detection limits make this technology superior to conventional analytical and monitoring methods; (2) severe difficulties exist for utilizing of radioactively labeled chemicals in geothermal operations. The labeling itself can cause technical problems. Another host of problems is caused by the reluctance of chemical manufacturers to release the necessary proprietary information on their chemicals required for proper labeling; and (3) previous attempts to manufacture radioactively labeled flocculants and to utilize them in a geothermal operation were prematurely abandoned for a number of reasons

  10. Chemical bond fundamental aspects of chemical bonding

    CERN Document Server

    Frenking, Gernot

    2014-01-01

    This is the perfect complement to ""Chemical Bonding - Across the Periodic Table"" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemica

  11. Ethics of Chemical Synthesis

    OpenAIRE

    Joachim Schummer

    2001-01-01

    Unlike other branches of science, the scientific products of synthetic chemistry are not only ideas but also new substances that change our material world, for the benefit or harm of living beings. This paper provides for the first time a systematical analysis of moral issues arising from chemical synthesis, based on concepts of responsibility and general morality. Topics include the questioning of moral neutrality of chemical synthesis as an end in itself, chemical weapons research, moral ob...

  12. Modelling the chemical evolution

    OpenAIRE

    Hensler, Gerhard; Recchi, Simone

    2010-01-01

    Advanced observational facilities allow to trace back the chemical evolution of the Universe, on the one hand, from local objects of different ages and, secondly, by direct observations of redshifted objects. The chemical enrichment serves as one of the cornerstones of cosmological evolution. In order to understand this chemical evolution in morphologically different astrophysical objects models are constructed based on analytical descriptions or numerical methods. For the comparison of their...

  13. Polymers for chemical sensing

    Directory of Open Access Journals (Sweden)

    Krishna C. Persaud

    2005-04-01

    Full Text Available Chemical sensors play an increasingly important role in monitoring the environment we live in, providing information on industrial manufacturing processes and their emissions, quality control of foods and beverages, and a host of other applications. Electrically conductive plastics are being developed for many useful applications. Improvement in understanding of the physical and chemical mechanisms by which electrical conduction occurs in these materials is now leading to a new generation of chemical sensors, which are reviewed in this article.

  14. Chemical and biological weapons

    International Nuclear Information System (INIS)

    This paper discusses the prospects of the multilateral negotiations aimed at achieving a complete and total ban on chemical weapons the Chemical Weapons convention (CWC). The control of the proliferation of chemical weapons is no longer just on East-West issue; it is also an issue of concern in Third World Countries, and in some of the wealthier middle eastern nations, such as Kuwait

  15. Laboratory of Chemical Physics

    Data.gov (United States)

    Federal Laboratory Consortium — Current research in the Laboratory of Chemical Physics is primarily concerned with experimental, theoretical, and computational problems in the structure, dynamics,...

  16. Introduction to chemical kinetics

    CERN Document Server

    Soustelle, Michel

    2013-01-01

    This book is a progressive presentation of kinetics of the chemical reactions. It provides complete coverage of the domain of chemical kinetics, which is necessary for the various future users in the fields of Chemistry, Physical Chemistry, Materials Science, Chemical Engineering, Macromolecular Chemistry and Combustion. It will help them to understand the most sophisticated knowledge of their future job area. Over 15 chapters, this book present the fundamentals of chemical kinetics, its relations with reaction mechanisms and kinetic properties. Two chapters are then devoted to experimental re

  17. Chemical defences against herbivores

    DEFF Research Database (Denmark)

    Pavia, Henrik; Baumgartner, Finn; Cervin, Gunnar;

    2012-01-01

    This chapter focuses on the recent and emerging research involving chemical defences against herbivory in aquatic primary producers. It provides an overview of plant chemical defence theories and highlights recent research on aquatic primary producers addressing a number of aspects of these...

  18. Chemical warfare in freshwater

    NARCIS (Netherlands)

    Mulderij, Gabi

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field expe

  19. Multiple chemical sensitivity

    DEFF Research Database (Denmark)

    Tran, Marie Thi Dao; Arendt-Nielsen, Lars; Kupers, Ron;

    2013-01-01

    BACKGROUND: Multiple Chemical Sensitivity (MCS) is a chronic condition characterized by recurrent, non-specific symptoms in response to chemically unrelated exposures in non-toxic concentrations. Although the pathophysiology of MCS remains unknown, central sensitization may be an important factor...

  20. Microorganisms and Chemical Pollution

    Science.gov (United States)

    Alexander, M.

    1973-01-01

    Discusses the importance of microorganisms in chemical pollution and pollution abatement. Selected chemical pollutants are chosen to illustrate that microorganisms synthesize hazardous substances from reasonably innocuous precursors, while others act as excellent environmental decontaminating agents by removing undesirable natural and synthetic…

  1. Chemical Product Design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    2004-01-01

    This paper highlights for a class of chemical products, the design process, their design with respect to the important issues, the need for appropriate tools and finally, lists some of the challenges and opportunities for the process systems engineering (PSE)/computer-aided process engineering...... (CAPE) community. The chemical products considered belong to the following types: chemical/biochemical/agrochemical products, coatings and solvents, food (nutraceuticals), HIM (household, industrial and institutional), personal care, pharmaceuticals and drugs. The challenges and opportunities are...... highlighted in terms of the needs for multi-level modeling with emphasis on property models that are suitable for computer-aided applications, flexible solution strategies that are able to solve a large range of chemical product design problems and finally, a systems chemical product design framework with the...

  2. Chemical recognition software

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.J. Jr.; Tisone, G.C.

    1994-12-01

    We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures. even when the mixture is noisy and contaminated with unknowns.

  3. Chemical recognition software

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.H. Jr.; Tisone, G.C.

    1994-06-01

    We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures, even when the mixture is noisy and contaminated with unknowns.

  4. Chemical evolution of galaxies

    CERN Document Server

    Matteucci, Francesca

    2012-01-01

    The term “chemical evolution of galaxies” refers to the evolution of abundances of chemical species in galaxies, which is due to nuclear processes occurring in stars and to gas flows into and out of galaxies. This book deals with the chemical evolution of galaxies of all morphological types (ellipticals, spirals and irregulars) and stresses the importance of the star formation histories in determining the properties of stellar populations in different galaxies. The topic is approached in a didactical and logical manner via galaxy evolution models which are compared with observational results obtained in the last two decades: The reader is given an introduction to the concept of chemical abundances and learns about the main stellar populations in our Galaxy as well as about the classification of galaxy types and their main observables. In the core of the book, the construction and solution of chemical evolution models are discussed in detail, followed by descriptions and interpretations of observations of ...

  5. Chemical process hazards analysis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The Office of Worker Health and Safety (EH-5) under the Assistant Secretary for the Environment, Safety and Health of the US Department (DOE) has published two handbooks for use by DOE contractors managing facilities and processes covered by the Occupational Safety and Health Administration (OSHA) Rule for Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119), herein referred to as the PSM Rule. The PSM Rule contains an integrated set of chemical process safety management elements designed to prevent chemical releases that can lead to catastrophic fires, explosions, or toxic exposures. The purpose of the two handbooks, ``Process Safety Management for Highly Hazardous Chemicals`` and ``Chemical Process Hazards Analysis,`` is to facilitate implementation of the provisions of the PSM Rule within the DOE. The purpose of this handbook ``Chemical Process Hazards Analysis,`` is to facilitate, within the DOE, the performance of chemical process hazards analyses (PrHAs) as required under the PSM Rule. It provides basic information for the performance of PrHAs, and should not be considered a complete resource on PrHA methods. Likewise, to determine if a facility is covered by the PSM rule, the reader should refer to the handbook, ``Process Safety Management for Highly Hazardous Chemicals`` (DOE- HDBK-1101-96). Promulgation of the PSM Rule has heightened the awareness of chemical safety management issues within the DOE. This handbook is intended for use by DOE facilities and processes covered by the PSM rule to facilitate contractor implementation of the PrHA element of the PSM Rule. However, contractors whose facilities and processes not covered by the PSM Rule may also use this handbook as a basis for conducting process hazards analyses as part of their good management practices. This handbook explains the minimum requirements for PrHAs outlined in the PSM Rule. Nowhere have requirements been added beyond what is specifically required by the rule.

  6. Chemical properties of transactinides

    Science.gov (United States)

    Gäggeler, H. W.

    2005-09-01

    First investigations of chemical properties of bohrium (Z = 107) and hassium (Z = 108) showed an expected behaviour as ordinary members of groups 7 and 8 of the periodic table. Two attempts to study element 112 yielded some indication for a behaviour like a very volatile noble metal. However, a very recent experiment to confirm this preliminary observation failed. Two examples are described how chemical studies may help to support element discovery claims from purely physics experiments. The two examples are the discovery claims of the elements 112 and 115, respectively, where the progenies hassium and dubnium were chemically identified.

  7. Chemical properties of transactinides

    International Nuclear Information System (INIS)

    First investigations of chemical properties of bohrium (Z = 107) and hassium (Z = 108) showed an expected behaviour as ordinary members of groups 7 and 8 of the periodic table. Two attempts to study element 112 yielded some indication for a behaviour like a very volatile noble metal. However, a very recent experiment to confirm this preliminary observation failed. Two examples are described how chemical studies may help to support element discovery claims from purely physics experiments. The two examples are the discovery claims of the elements 112 and 115, respectively, where the progenies hassium and dubnium were chemically identified. (orig.)

  8. Chemical properties of transactinides

    Energy Technology Data Exchange (ETDEWEB)

    Gaeggeler, H.W. [Paul Scherrer Institut, Villigen (Switzerland); University of Bern, Bern (Switzerland)

    2005-09-01

    First investigations of chemical properties of bohrium (Z = 107) and hassium (Z = 108) showed an expected behaviour as ordinary members of groups 7 and 8 of the periodic table. Two attempts to study element 112 yielded some indication for a behaviour like a very volatile noble metal. However, a very recent experiment to confirm this preliminary observation failed. Two examples are described how chemical studies may help to support element discovery claims from purely physics experiments. The two examples are the discovery claims of the elements 112 and 115, respectively, where the progenies hassium and dubnium were chemically identified. (orig.)

  9. Chemical Data Access Tool

    Data.gov (United States)

    U.S. Environmental Protection Agency — This tool is intended to aid individuals interested in learning more about chemicals that are manufactured or imported into the United States. Health and safety...

  10. Ethics of Chemical Synthesis

    Directory of Open Access Journals (Sweden)

    Joachim Schummer

    2001-10-01

    Full Text Available Unlike other branches of science, the scientific products of synthetic chemistry are not only ideas but also new substances that change our material world, for the benefit or harm of living beings. This paper provides for the first time a systematical analysis of moral issues arising from chemical synthesis, based on concepts of responsibility and general morality. Topics include the questioning of moral neutrality of chemical synthesis as an end in itself, chemical weapons research, moral objections against improving material conditions of life by chemical means, and freedom of research. The paper aims at providing both a sound basis for moral judgements of chemistry in a public discourse and a framework for chemists to reflect on the moral relevance of their activity.

  11. Chemical allergy in humans

    DEFF Research Database (Denmark)

    Kimber, Ian; Basketter, David A; Thyssen, Jacob P;

    2014-01-01

    reaction; that is, allergic contact dermatitis or sensitization of the respiratory tract associated with occupational asthma. Studies in rodents have revealed that differential forms of allergic sensitization to chemicals are, in large part at least, a function of the selective development of discrete......Abstract There is considerable interest in the immunobiological processes through which the development of allergic sensitization to chemicals is initiated and orchestrated. One of the most intriguing issues is the basis for the elicitation by chemical sensitizers of different forms of allergic...... functional sub-populations of CD4(+) and CD8(+) T-lymphocytes. Evidence for a similar association of chemical allergy in humans with discrete T-lymphocyte populations is, however, limited. It is of some interest, therefore, that two recent articles from different teams of investigators have shed new light on...

  12. Chemical burn or reaction

    Science.gov (United States)

    ... and buy only as much as needed. Many household products are made of toxic chemicals. It is important ... follow label instructions, including any precautions. Never store household products in food or drink containers. Leave them in ...

  13. Biotechnology for renewable chemicals

    DEFF Research Database (Denmark)

    Borodina, Irina; Kildegaard, Kanchana Rueksomtawin; Jensen, Niels Bjerg;

    2014-01-01

    The majority of the industrial organic chemicals are derived from fossil sources. With the oil and gas resources becoming limiting, biotechnology offers a sustainable alternative for production ofchemicals from renewable feedstocks. Yeast is an attractive cell factory forsustainable production...

  14. Household Chemical Emergencies

    Science.gov (United States)

    ... and disposing of the material according to the manufacturer’s directions. It is critical to store household chemicals in places where children cannot access them. Remember that products such as aerosol cans of hair spray and deodorant, nail polish ...

  15. Chemical Physics Summer School

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-06-28

    The Gordon Research Conference (GRC) on Chemical Physics Summer School was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  16. Fiber optic chemical sensors

    Science.gov (United States)

    Jung, Chuck C.; McCrae, David A.; Saaski, Elric W.

    1998-09-01

    This paper provides a broad overview of the field of fiber optic chemical sensors. Several different types of fiber optic sensors and probes are described, and references are cited for each category discussed.

  17. Chemical evolution and life

    Directory of Open Access Journals (Sweden)

    Malaterre Christophe

    2015-01-01

    Full Text Available In research on the origins of life, the concept of “chemical evolution” aims at explaining the transition from non-living matter to living matter. There is however strong disagreement when it comes to defining this concept more precisely, and in particular with reference to a chemical form of Darwinian evolution: for some, chemical evolution is nothing but Darwinian evolution applied to chemical systems before life appeared; yet, for others, it is the type of evolution that happened before natural selection took place, the latter being the birthmark of living systems. In this contribution, I review the arguments defended by each side and show how both views presuppose a dichotomous definition of “life”.

  18. [Cutaneous absorption of chemicals].

    Science.gov (United States)

    Schröder, J

    1986-09-01

    Chemicals have become indispensible for the maintenance of health in animals and man. The route of administration of each medicament is decided by factors such as site of desired action, chemistry of the active ingredient, age and species of the patient, and frequency of administration (or desired duration of activity). In situations where the oral and hypodermic routes, which are used most frequently, are inadequate or unsatisfactory, dermal application can provide a valuable alternative method to achieve systemic activity. Examples of formulations currently available for dermal application contain diverse chemicals and are intended for a variety of purposes, such as crufomate against cattle grubs, fenthion against cattle lice, levamisole against gastrointestinal nematodes, nitroglycerine for angina pectoris, and scopolamine for motion sickness. The skin acts as a barrier to penetration by chemicals and micro-organisms by virtue of its morphology and chemical composition. Chemicals which do penetrate, do not necessarily pass through the appendages (hair follicles and gland ducts), but mostly penetrate through the interjacent epidermis, either through the cells, or via the intracellular spaces. These spaces have recently been shown by electron microscopy to be filled by an amorphous substance which exudes on the skin surface in convex ridges. This substance has a lipid nature, but is not hydrophobic as is often accepted. For a chemical to be able to penetrate the skin, it must be partially water and lipid soluble, polar, and weakly ionizing. A variety of factors can possibly affect the permeability of skin for a chemical. These include species differences in morphology (skin thickness, tightness of intercellular junctions, density of hair follicles and other appendages), biochemistry, and physiology; seasonal and climatic variations; and differences between breeds and genders. Species differences in skin permeability are largely unpredictable and inconsistent. An

  19. Computational Systems Chemical Biology

    OpenAIRE

    Oprea, Tudor I.; May, Elebeoba E.; Leitão, Andrei; Tropsha, Alexander

    2011-01-01

    There is a critical need for improving the level of chemistry awareness in systems biology. The data and information related to modulation of genes and proteins by small molecules continue to accumulate at the same time as simulation tools in systems biology and whole body physiologically-based pharmacokinetics (PBPK) continue to evolve. We called this emerging area at the interface between chemical biology and systems biology systems chemical biology, SCB (Oprea et al., 2007).

  20. Chemical functionalization of graphene

    OpenAIRE

    Boukhvalov, D. W.; Katsnelson, M I

    2008-01-01

    Experimental and theoretical results on chemical functionalization of graphene are reviewed. Using hydrogenated graphene as a model system, general principles of the chemical functionalization are formulated and discussed. It is shown that, as a rule, 100% coverage of graphene by complex functional groups (in contrast with hydrogen and fluorine) is unreachable. A possible destruction of graphene nanoribbons by fluorine is considered. The functionalization of infinite graphene and graphene nan...

  1. Chemical effects of radiation

    International Nuclear Information System (INIS)

    Ionizing radiations initiate chemical changes in materials because of the high energy of their quanta. In water, highly reactive free radicals are produced which can initiate secondary changes of solutes, and in chemical of biological molecules in contact with the water. Free radicals can also be directly produced in irradiated medical products. Their fate can be identified and the molecular basis of radiation inactivation clarified. Methods have now been developed to protect and minimise such radiation damage. (author)

  2. Polymers for chemical sensing

    OpenAIRE

    Persaud, Krishna C.

    2005-01-01

    Chemical sensors play an increasingly important role in monitoring the environment we live in, providing information on industrial manufacturing processes and their emissions, quality control of foods and beverages, and a host of other applications. Electrically conductive plastics are being developed for many useful applications. Improvement in understanding of the physical and chemical mechanisms by which electrical conduction occurs in these materials is now leading to a new generation of ...

  3. Chemical warfare in freshwater

    OpenAIRE

    Mulderij, Gabi

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field experiments we studied the allelopathic effects of the aquatic macrophytes, Chara and Stratiotes. Laboratory experiments showed that the aquatic macrophytes had allelopathic effects. Phytoplankton grow...

  4. Interactive Chemical Reactivity Exploration

    OpenAIRE

    Haag, Moritz P.; Vaucher, Alain C.; Bosson, Mael; Redon, Stephane; Reiher, Markus

    2014-01-01

    Elucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black-box search methods to find intermediates and transition-state structures might fail in such situations because of the high-dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist's intuition into the search process. ...

  5. Environmental/chemical thesaurus

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, C.R.; Dailey, N.S.; Jordan, A.C.; Miller, K.C.; Owens, E.T.; Rickert, L.W.

    1978-06-01

    The Environmental/Chemical Thesaurus approaches scientific language control problems from a multidisciplinary view. The Environmental/Biomedical Terminology Index (EBTI) was used as a base for the present thesaurus. The Environmental/Chemical Thesaurus, funded by the Environmental Protection Agency, used as its source of new terms those major terms found in 13 Environmental Protection Agency data bases. The scope of this thesaurus includes not only environmental and biomedical sciences, but also the physical sciences with emphasis placed on chemistry. Specific chemical compounds are not included; only classes of chemicals are given. To adhere to this level of classification, drugs and pesticides are identified by class rather than by specific chemical name. An attempt was also made to expand the areas of sociology and economics. Terminology dealing with law, demography, and geography was expanded. Proper names of languages and races were excluded. Geographic terms were expanded to include proper names for oceans, continents, major lakes, rivers, and islands. Political divisions were added to allow for proper names of countries and states. With such a broad scope, terminology for specific sciences does not provide for indexing to the lowest levels in plant, animal, or chemical classifications.

  6. Environmental/chemical thesaurus

    International Nuclear Information System (INIS)

    The Environmental/Chemical Thesaurus approaches scientific language control problems from a multidisciplinary view. The Environmental/Biomedical Terminology Index (EBTI) was used as a base for the present thesaurus. The Environmental/Chemical Thesaurus, funded by the Environmental Protection Agency, used as its source of new terms those major terms found in 13 Environmental Protection Agency data bases. The scope of this thesaurus includes not only environmental and biomedical sciences, but also the physical sciences with emphasis placed on chemistry. Specific chemical compounds are not included; only classes of chemicals are given. To adhere to this level of classification, drugs and pesticides are identified by class rather than by specific chemical name. An attempt was also made to expand the areas of sociology and economics. Terminology dealing with law, demography, and geography was expanded. Proper names of languages and races were excluded. Geographic terms were expanded to include proper names for oceans, continents, major lakes, rivers, and islands. Political divisions were added to allow for proper names of countries and states. With such a broad scope, terminology for specific sciences does not provide for indexing to the lowest levels in plant, animal, or chemical classifications

  7. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  8. Islamic State and Chemical Weapons

    Directory of Open Access Journals (Sweden)

    Lukáš Rafay

    2016-09-01

    Full Text Available The article deals with topic of Islamic State and chemical weapons. The issue is analysed in three dimensions: origin of used chemical weapons and possibility of independent production; known chemical attacks and tactical regularities in their execution; and traits of future chemical terrorist attacks. By providing a thorough examination of the problem, the article aims at predicting the future development of the group’s chemical program as well as describing any prospective chemical terrorist attacks in Europe

  9. Protein Chemical Shift Prediction

    CERN Document Server

    Larsen, Anders S

    2014-01-01

    The protein chemical shifts holds a large amount of information about the 3-dimensional structure of the protein. A number of chemical shift predictors based on the relationship between structures resolved with X-ray crystallography and the corresponding experimental chemical shifts have been developed. These empirical predictors are very accurate on X-ray structures but tends to be insensitive to small structural changes. To overcome this limitation it has been suggested to make chemical shift predictors based on quantum mechanical(QM) calculations. In this thesis the development of the QM derived chemical shift predictor Procs14 is presented. Procs14 is based on 2.35 million density functional theory(DFT) calculations on tripeptides and contains corrections for hydrogen bonding, ring current and the effect of the previous and following residue. Procs14 is capable at performing predictions for the 13CA, 13CB, 13CO, 15NH, 1HN and 1HA backbone atoms. In order to benchmark Procs14, a number of QM NMR calculatio...

  10. Biological and Chemical Security

    Energy Technology Data Exchange (ETDEWEB)

    Fitch, P J

    2002-12-19

    The LLNL Chemical & Biological National Security Program (CBNP) provides science, technology and integrated systems for chemical and biological security. Our approach is to develop and field advanced strategies that dramatically improve the nation's capabilities to prevent, prepare for, detect, and respond to terrorist use of chemical or biological weapons. Recent events show the importance of civilian defense against terrorism. The 1995 nerve gas attack in Tokyo's subway served to catalyze and focus the early LLNL program on civilian counter terrorism. In the same year, LLNL began CBNP using Laboratory-Directed R&D investments and a focus on biodetection. The Nunn-Lugar-Domenici Defense Against Weapons of Mass Destruction Act, passed in 1996, initiated a number of U.S. nonproliferation and counter-terrorism programs including the DOE (now NNSA) Chemical and Biological Nonproliferation Program (also known as CBNP). In 2002, the Department of Homeland Security was formed. The NNSA CBNP and many of the LLNL CBNP activities are being transferred as the new Department becomes operational. LLNL has a long history in national security including nonproliferation of weapons of mass destruction. In biology, LLNL had a key role in starting and implementing the Human Genome Project and, more recently, the Microbial Genome Program. LLNL has over 1,000 scientists and engineers with relevant expertise in biology, chemistry, decontamination, instrumentation, microtechnologies, atmospheric modeling, and field experimentation. Over 150 LLNL scientists and engineers work full time on chemical and biological national security projects.

  11. Accessing and using chemical databases

    DEFF Research Database (Denmark)

    Nikolov, Nikolai Georgiev; Pavlov, Todor; Niemelä, Jay Russell;

    2013-01-01

    Computer-based representation of chemicals makes it possible to organize data in chemical databases-collections of chemical structures and associated properties. Databases are widely used wherever efficient processing of chemical information is needed, including search, storage, retrieval, and...... dissemination. Structure and functionality of chemical databases are considered. The typical kinds of information found in a chemical database are considered-identification, structural, and associated data. Functionality of chemical databases is presented, with examples of search and access types. More details...... are included about the OASIS database and platform and the Danish (Q)SAR Database online. Various types of chemical database resources are discussed, together with a list of examples....

  12. Endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Mandrup, Karen

    BACKGROUND: Endocrine disrupting chemicals (EDCs) may contribute to reproductive changes in boys in the Western world, however, less is known about influence of EDCs in women. The incidence of precocious breast development is increasing in USA and Europe and mammary gland development has been...... examination showed changes in epithelial morphology in male (hypertrophic epithelium) and female (lobuloalveolar morphology) mammary glands in adult rats exposed to phytoestrogens. Anti-androgenic chemicals showed signs of feminisation of adult male mammary glands. No effects of anti-androgens were observed...... in female mammary glands. The histological changes observed in adult female and male mammary glands were not present consistently in the groups of estrogenic or anti-androgenic chemicals and may be due to other modes of action of thechemicals. Female genital malformations were affected by the potent...

  13. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  14. Nanotechnology for chemical engineers

    CERN Document Server

    Salaheldeen Elnashaie, Said; Hashemipour Rafsanjani, Hassan

    2015-01-01

    The book describes the basic principles of transforming nano-technology into nano-engineering with a particular focus on chemical engineering fundamentals. This book provides vital information about differences between descriptive technology and quantitative engineering for students as well as working professionals in various fields of nanotechnology. Besides chemical engineering principles, the fundamentals of nanotechnology are also covered along with detailed explanation of several specific nanoscale processes from chemical engineering point of view. This information is presented in form of practical examples and case studies that help the engineers and researchers to integrate the processes which can meet the commercial production. It is worth mentioning here that, the main challenge in nanostructure and nanodevices production is nowadays related to the economic point of view. The uniqueness of this book is a balance between important insights into the synthetic methods of nano-structures and nanomaterial...

  15. Applied chemical engineering thermodynamics

    CERN Document Server

    Tassios, Dimitrios P

    1993-01-01

    Applied Chemical Engineering Thermodynamics provides the undergraduate and graduate student of chemical engineering with the basic knowledge, the methodology and the references he needs to apply it in industrial practice. Thus, in addition to the classical topics of the laws of thermodynamics,pure component and mixture thermodynamic properties as well as phase and chemical equilibria the reader will find: - history of thermodynamics - energy conservation - internmolecular forces and molecular thermodynamics - cubic equations of state - statistical mechanics. A great number of calculated problems with solutions and an appendix with numerous tables of numbers of practical importance are extremely helpful for applied calculations. The computer programs on the included disk help the student to become familiar with the typical methods used in industry for volumetric and vapor-liquid equilibria calculations.

  16. Chemical crowd control agents.

    Science.gov (United States)

    Menezes, Ritesh G; Hussain, Syed Ather; Rameez, Mansoor Ali Merchant; Kharoshah, Magdy A; Madadin, Mohammed; Anwar, Naureen; Senthilkumaran, Subramanian

    2016-03-01

    Chemical crowd control agents are also referred to as riot control agents and are mainly used by civil authorities and government agencies to curtail civil disobedience gatherings or processions by large crowds. Common riot control agents used to disperse large numbers of individuals into smaller, less destructive, and more easily controllable numbers include chloroacetophenone, chlorobenzylidenemalononitrile, dibenzoxazepine, diphenylaminearsine, and oleoresin capsicum. In this paper, we discuss the emergency medical care needed by sufferers of acute chemical agent contamination and raise important issues concerning toxicology, safety and health. PMID:26658556

  17. CHEMICAL TOXICITY OF URANIUM

    OpenAIRE

    2007-01-01

    Uranium, occurs naturally in the earth’s crust, is an alpha emitter radioactive element from the actinide group. For this reason, U-235 and U-238, are uranium isotopes with long half lives, have got radiological toxicity. But, for natural-isotopic-composition uranium (NatU), there is greater risk from chemical toxicity than radiological toxicity. When uranium is get into the body with anyway, also its chemical toxicity must be thought. [TAF Prev Med Bull 2007; 6(3.000): 215-220

  18. Chemicals in material cycles

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Eriksson, Eva; Astrup, Thomas Fruergaard

    2015-01-01

    Material recycling has been found beneficial in terms of resource and energy performance and is greatly promoted throughout the world. A variety of chemicals is used in materials as additives and data on their presence is sparse. The present work dealt with paper as recyclable material and...... diisobutyl phthalate (DiBP) as chemical in focus. The results showed variations, between 0.83 and 32 μg/g, in the presence of DiBP in Danish waste paper and board and potential accumulation due to recycling....

  19. CHEMICAL TOXICITY OF URANIUM

    Directory of Open Access Journals (Sweden)

    Sermin Cam

    2007-06-01

    Full Text Available Uranium, occurs naturally in the earth’s crust, is an alpha emitter radioactive element from the actinide group. For this reason, U-235 and U-238, are uranium isotopes with long half lives, have got radiological toxicity. But, for natural-isotopic-composition uranium (NatU, there is greater risk from chemical toxicity than radiological toxicity. When uranium is get into the body with anyway, also its chemical toxicity must be thought. [TAF Prev Med Bull 2007; 6(3.000: 215-220

  20. Magnetic chemically peculiar stars

    CERN Document Server

    Schöller, Markus

    2015-01-01

    Chemically peculiar (CP) stars are main-sequence A and B stars with abnormally strong or weak lines for certain elements. They generally have magnetic fields and all observables tend to vary with the same period. Chemically peculiar stars provide a wealth of information; they are natural atomic and magnetic laboratories. After a brief historical overview, we discuss the general properties of the magnetic fields in CP stars, describe the oblique rotator model, explain the dependence of the magnetic field strength on the rotation, and concentrate at the end on HgMn stars.

  1. Idaho Chemical Processing Plant safety document ICPP hazardous chemical evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Harwood, B.J.

    1993-01-01

    This report presents the results of a hazardous chemical evaluation performed for the Idaho Chemical Processing Plant (ICPP). ICPP tracks chemicals on a computerized database, Haz Track, that contains roughly 2000 individual chemicals. The database contains information about each chemical, such as its form (solid, liquid, or gas); quantity, either in weight or volume; and its location. The Haz Track database was used as the primary starting point for the chemical evaluation presented in this report. The chemical data and results presented here are not intended to provide limits, but to provide a starting point for nonradiological hazards analysis.

  2. Active Chemical Sampling System for Underwater Chemical Source Localization

    OpenAIRE

    Ryuichi Takemura; Hiromi Sakata; Hiroshi Ishida

    2016-01-01

    This paper investigates the effect of active water sampling to enhance chemical reception for small underwater robots. The search for a chemical source in a stagnant water environment is not an easy task because the chemical solution released from the source stays in the close vicinity of the source. No signal is obtained even if a robot with chemical sensors is placed a few centimeters from the chemical source. In the system under study, four electrochemical sensors are aligned in front of a...

  3. Chemical Aspects of Dentistry.

    Science.gov (United States)

    Helfman, Murry

    1982-01-01

    Dental caries (tooth decay) and periodontal (gum) disease are treated/prevented by procedures utilizing chemical expertise. Procedures and suggestions on how they might be incorporated into the high school chemistry curriculum are described. Specific topics discussed include dental caries, fluoride, diet, tooth decay prevention, silver amalgan,…

  4. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2008-01-01

    This series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline. This stand-alone special topics volume reports recent advances in electron-transfer research with significant, up-to-date chapters by internationally recognized researchers.

  5. Pesticides: chemicals for survival

    International Nuclear Information System (INIS)

    Pesticides are chemicals used to control pests such as insects, weeds, plant diseases, nematodes, and rodents. The increased use of pesticides since 1945 has greatly aided the increase in crop production, protected livestock from diseases such as trypanosomiasis, protected man from diseases such as malaria and filarisis, decreased losses of stored grain, and has generally improved man's welfare. Despite the enormous benefits derived from pesticides these chemicals are not problem-free. Many pesticides are toxic to living organisms and interfere with specific biochemical systems. To measure the very small quantities of a pesticide radiolabelled chemicals are frequently essential, particularly to measure changes in the chemical structure of the pesticide, movement of the pesticide in soil, plants, or animals, amounts of pesticide going through various steps in food processing, etc. The use of radiolabelled pesticides is shortly shown for metabolism of the pesticide in crop species, metabolism in ruminant, in chickens and eggs, in soil, and possibly leaching and sorption in soil, hydrolysis, bio-concentration, microbial and photodegradation, and toxicity studies

  6. Chemical conditioning of sludge

    Energy Technology Data Exchange (ETDEWEB)

    Novak, John T.; Park, Chul

    2003-07-01

    With all the advances made in understanding the structure and composition of sewage sludges, chemical conditioning remains a trial and error process, both with regard to the type and dose of conditioner needed. Recent studies at Virginia Tech have found that biological floc consists of two types of biopolymer, material associated with iron and aluminum and material associated with calcium and magnesium. These materials behave differently when sludges undergo digestion. This results in very different material being released into solution during digestion and very different conditioning requirements. This study shows that the primary materials released during anaerobic digestion are proteins and coagulation of the colloidal protein fraction in solution is the primary mechanism for conditioning. For aerobically digested sludges, both proteins and polysaccharides make up the colloid fraction that interferes with dewatering. This research also shows that the effectiveness of the digestion process as characterized by volatile solids destruction is directly related to the chemical dose required for conditioning. That is, as the solids destruction increases, the conditioning chemical requirement also increases. Well-digested sludges dewater more poorly and require more conditioning chemical that those with less volatile solids destruction. (author)

  7. Chemical hygiene plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    This plan was written to administer and monitor safety measures and chemical hygiene principles in the TAC Uranium Mill Tailing Remedial Action Project sample preparation facility in Albuquerque, New Mexico. It applies to toxic and/or hazardous materials to radioactive materials.

  8. Power plant chemical technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    17 contributions covering topies of fossil fuel combustion, flue gas cleaning, power plant materials, corrosion, water/steam cycle chemistry, monitoring and control were presented at the annual meeting devoted to Power Plant Chemical Technology 1996 at Kolding (Denmark) 4-6 September 1996. (EG)

  9. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...... are mentioned. References to review papers, papers with experimental data, and papers describing the thermodynamic modelling of the systems are given....

  10. Risks and Chemical Substances.

    Science.gov (United States)

    Blumberg, Avrom A.

    1994-01-01

    Examines exposure to chemicals within the home and three important ways in which hazardous substances can be identified and evaluated. Suggests a rational picture of human health risks and contains an introductory discussion of reasons for exposure, epidemiology, cancer causes and patterns, animal testing, toxins, and risk. (LZ)

  11. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  12. Multiple Chemical Sensitivity

    DEFF Research Database (Denmark)

    Junge, Anne Gram

    Et voksende antal mennesker i Danmark oplever at være overfølsomme over for dufte og kemikalier. Imidlertid er den tilskrevne diagnose Multiple Chemical Sensitivity (MCS) ikke medicinsk anerkendt i Danmark pga. mangel på organiske og patofysiologisk basis for symptomerne. Dette speciale bygger på...

  13. Bulk chemicals from biomass

    NARCIS (Netherlands)

    Haveren, van J.; Scott, E.L.; Sanders, J.P.M.

    2008-01-01

    Given the current robust forces driving sustainable production, and available biomass conversion technologies, biomass-based routes are expected to make a significant impact on the production of bulk chemicals within 10 years, and a huge impact within 20-30 years. In the Port of Rotterdam there is a

  14. Precision Chemical Abundance Measurements

    DEFF Research Database (Denmark)

    Yong, David; Grundahl, Frank; Meléndez, Jorge;

    2012-01-01

    This talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios. Our results indicate that the ob...

  15. Visualization in chemical education

    OpenAIRE

    Giordan, Marcelo; Góis, Jackson; Arroio, Agnaldo

    2005-01-01

    In this present study, we investigated the capabilities of computer-based construction tool Construtor that allowed students to build virtual molecular models and view multiple chemical representations using computational molecular simulations. Construtor integrates various supports for learning of molecular structure meaning based on representation levels. The findings also suggest that computer based models can help students to make translations among representation levels.

  16. Chemical and Petrochemical Sector

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    This publication is a background document on the global chemical and petrochemical sector for the IEA publication Energy Technology Transitions in Industry (IEA, 2009). It provides further, more detailed information on the methodology and data issues for energy efficiency indicators for the sector. The indicators discussed offer insight regarding the energy efficiency improvement potential in the short- to medium-term (by proven technologies).

  17. Modeling chemical kinetics graphically

    NARCIS (Netherlands)

    A. Heck

    2012-01-01

    In literature on chemistry education it has often been suggested that students, at high school level and beyond, can benefit in their studies of chemical kinetics from computer supported activities. Use of system dynamics modeling software is one of the suggested quantitative approaches that could h

  18. Chemical Inhibition of Autophagy

    DEFF Research Database (Denmark)

    Baek, Eric; Lin Kim, Che; Gyeom Kim, Mi;

    2016-01-01

    Chinese hamster ovary (CHO) cells activate and undergo apoptosis and autophagy for various environmental stresses. Unlike apoptosis, studies on increasing the production of therapeutic proteins in CHO cells by targeting the autophagy pathway are limited. In order to identify the effects of chemic...

  19. Chemical Safety – Introduction

    CERN Multimedia

    DG Unit

    2009-01-01

    A course of "Chemical Safety – Introduction" will be held in English on 29 May 2009, 9:30-12:00. There are some places left. If you are interested in participating, please register on the Training Catalogue. You will then receive an invitation by email.

  20. Chemical plume source localization.

    Science.gov (United States)

    Pang, Shuo; Farrell, Jay A

    2006-10-01

    This paper addresses the problem of estimating a likelihood map for the location of the source of a chemical plume using an autonomous vehicle as a sensor probe in a fluid flow. The fluid flow is assumed to have a high Reynolds number. Therefore, the dispersion of the chemical is dominated by turbulence, resulting in an intermittent chemical signal. The vehicle is capable of detecting above-threshold chemical concentration and sensing the fluid flow velocity at the vehicle location. This paper reviews instances of biological plume tracing and reviews previous strategies for a vehicle-based plume tracing. The main contribution is a new source-likelihood mapping approach based on Bayesian inference methods. Using this Bayesian methodology, the source-likelihood map is propagated through time and updated in response to both detection and nondetection events. Examples are included that use data from in-water testing to compare the mapping approach derived herein with the map derived using a previously existing technique. PMID:17036813

  1. The renewable chemicals industry

    DEFF Research Database (Denmark)

    Christensen, Claus H.; Rass-Hansen, J.; Marsden, Charlotte Clare;

    2008-01-01

    and educational tools are introduced to allow initial estimates of which chemical processes could be viable. Specifically, fossil and renewables value chains are used to indicate where renewable feedstocks can be optimally valorized. Additionally, C factors are introduced that specify the amount of CO2 produced...... to arrive at cost-competitive and environmentally friendly processes....

  2. Chemical conditioning of sludge.

    Science.gov (United States)

    Novak, J T; Park, C

    2004-01-01

    With all the advances made in understanding the structure and composition of sewage sludges, chemical conditioning remains a trial and error process, both with regard to the type and dose of conditioner needed. Recent studies at Virginia Tech have found that biological floc consists of two types of biopolymer, material associated with iron and aluminium and material associated with calcium and magnesium. These materials behave differently when sludges undergo digestion. This results in very different material being released into solution during digestion and very different conditioning requirements. This study shows that the primary materials released during anaerobic digestion are proteins and coagulation of the colloidal protein fraction in solution is the primary mechanism for conditioning. For aerobically digested sludges, both proteins and polysaccharides make up the colloid fraction, which interferes with dewatering. This research also shows that the effectiveness of the digestion process as characterized by volatile solids destruction is directly related to the chemical dose required for conditioning. That is, as the solids destruction increases, the conditioning chemical requirement also increases. Well digested sludges dewater more poorly and require more conditioning chemical than those with less volatile solids destruction. PMID:15259940

  3. Chemical warfare in termites

    Czech Academy of Sciences Publication Activity Database

    Šobotník, Jan; Jirošová, Anna; Hanus, Robert

    2010-01-01

    Roč. 56, č. 9 (2010), s. 1012-1021. ISSN 0022-1910 R&D Projects: GA AV ČR IAA600550614 Institutional research plan: CEZ:AV0Z40550506 Keywords : Isoptera * chemical defense * exocrine gland * frontal gland Subject RIV: CC - Organic Chemistry Impact factor: 2.310, year: 2010

  4. Chemical hygiene plan

    International Nuclear Information System (INIS)

    This plan was written to administer and monitor safety measures and chemical hygiene principles in the TAC Uranium Mill Tailing Remedial Action Project sample preparation facility in Albuquerque, New Mexico. It applies to toxic and/or hazardous materials to radioactive materials

  5. Environmental Chemicals in Breast Milk

    Science.gov (United States)

    Most of the information available on environmental chemicals in breast milk is focused on persistent, lipophilic chemicals; the database on levels of these chemicals has expanded substantially since the 1950s. Currently, various types of chemicals are measured in breast milk and ...

  6. Global chemical pollution

    International Nuclear Information System (INIS)

    Over the past decade, public and governmental awareness of environmental problems has grown steadily, with an accompanying increase in the regulation of point sources of pollution. As a result, great strides have been made in cleaning polluted rivers and decreasing air pollution near factories. However, traditional regulatory approaches to environmental pollution have focused primarily on protecting the maximally exposed individual located in the immediate vicinity of the pollution source. Little attention has been given to the global implications of human production and use of synthetic chemicals. A consensus is emerging that even trace levels of environmental contamination can have potentially devastating environmental consequences. The authors maintain that ambient levels of pollution have risen to the point where human health is being affected on a global scale. Atmospheric transport is recognized as the primary mode of global distribution and entry into the food chain for organic chemicals. The following are examples of global chemical pollutants that result in human exposure of significant proportions: PCBs, dioxins, benzene, mercury and lead. Current regulatory approaches for environmental pollution do not incorporate ways of dealing with global pollution. Instead the major focus has been on protecting the maximally exposed individual. If we do not want to change our standard of living, the only way to reduce global chemical pollution is to make production and consumption processes more efficient and to lower the levels of production of these toxic chemicals. Thus the only reasonable solution to global pollution is not increased regulation of isolated point sources, but rather an increased emphasis on waste reduction and materials recycling. Until we focus on these issues, we will continue to experience background cancer risk in the 10-3 range

  7. Chemical Engineering in Space

    Science.gov (United States)

    Lobmeyer, Dennis A.; Meneghelli, Barry; Steinrock, Todd (Technical Monitor)

    2001-01-01

    The aerospace industry has long been perceived as the domain of both physicists and mechanical engineers. This perception has endured even though the primary method of providing the thrust necessary to launch a rocket into space is chemical in nature. The chemical engineering and chemistry personnel behind the systems that provide access to space have labored in the shadows of the physicists and mechanical engineers. As exploration into the cosmos moves farther away from Earth, there is a very distinct need for new chemical processes to help provide the means for advanced space exploration. The state of the art in launch systems uses chemical propulsion systems, primarily liquid hydrogen and liquid oxygen, to provide the energy necessary to achieve orbit. As we move away from Earth, there are additional options for propulsion. Unfortunately, few of these options can compare to the speed or ease of use provided by the chemical propulsion agents. It is with great care and significant cost that gaseous compounds such as hydrogen and oxygen are liquefied and become dense enough to use for rocket fuel. These low-temperature liquids fall within a specialty area known as cryogenics. Cryogenics, the science and art of producing cold operating conditions for use on Earth, in orbit, or on some other nonterrestrial body, has become increasingly important to our ability to travel within our solar system. The production of cryogenic fuels and the long-term storage of these fluids are necessary for travel. As our explorations move farther away from Earth, we need to address how to produce the necessary fuels to make a round-trip. The cost and the size of these expeditions are extreme at best. If we take everything necessary for our survival for the round-trip, we invalidate any chance of travel in the near future. As with the early explorers on Earth, we need to harvest much of our energy and our life support from the celestial bodies. The in situ production of these energy

  8. COOEE bitumen: chemical aging

    CERN Document Server

    Lemarchand, Claire A; Dyre, Jeppe C; Hansen, Jesper S

    2013-01-01

    We study chemical aging in "COOEE bitumen" using molecular dynamic simulations. The model bitumen is composed of four realistic molecule types: saturated hydrocarbon, resinous oil, resin, and asphaltene. The aging reaction is modelled by the chemical reaction: "2 resins $\\rightarrow$ 1 asphaltene". Molecular dynamic simulations of four bitumen compositions, obtained by a repeated application of the aging reaction, are performed. The stress autocorrelation function, the fluid structure, the rotational dynamics of the plane aromatic molecules, and the diffusivity of each molecule, are determined for the four different compositions. The aging reaction causes a significant dynamics slowdown, which is correlated to the aggregation of asphaltene molecules in larger and dynamically slower nanoaggregates. Finally, a detailed description of the role of each molecule types in the aggregation and aging processes is given.

  9. Cyanobacterial chemical production.

    Science.gov (United States)

    Case, Anna E; Atsumi, Shota

    2016-08-10

    The increase in global temperatures caused by rising CO2 levels necessitates the development of alternative sources of fuel and chemicals. One appealing alternative that has been receiving increased attention in recent years is the photosynthetic conversion of atmospheric CO2 to biofuels and chemical products using genetically engineered cyanobacteria. This can help to not only provide an alternate "greener" source for some of the most popular petroleum based products but it can also help to reduce atmospheric CO2. Utilizing cyanobacteria rather than plants allows for reduced land requirements and reduces competition with food crops. This review discusses advancements in the field since 2012 with a particular emphasis on production of hydrocarbons. PMID:27238233

  10. Chemical durability of zircon

    Science.gov (United States)

    Trocellier, Patrick; Delmas, Robert

    2001-07-01

    Zircon (ZrSiO 4) exhibits a strong structural affinity for uranium and thorium together with a very high chemical durability. This makes it a potential crystalline host matrix to immobilize actinides issued from separation of nuclear wastes. Irradiation induces amorphization of the crystalline structure (the metamictization process) and thus may decrease the chemical durability of the material. Leaching tests have been conducted on natural zircons from Brazil and Madagascar at 96°C for a period of 1 month, using deionized water. Leachates have been analysed by inductively coupled plasma mass spectrometry (ICP-MS) and UV-visible spectrophotometry. Zircon solid surfaces have been investigated by coupling scanning electron microscopy and X-ray microanalysis (SEM-EDX) with nuclear microprobe analysis ( μPIXE, μRBS and μERDA). From the mass balance between leachates and hydrated surfaces, the probable mechanisms of zircon aqueous alteration are presented and discussed.

  11. Autocatalytic chemical smoke rings

    CERN Document Server

    Rogers, M C; Rogers, Michael C.; Morris, Stephen W.

    2005-01-01

    Buoyant plumes, evolving free of boundary constraints, may develop well-defined mushroom shaped heads. In normal plumes, overturning flow in the head entrains less buoyant fluid from the surroundings as the head rises, robbing the plume of its driving force. We consider here a new type of plume in which the source of buoyancy is an autocatalytic chemical reaction. The reaction occurs at a sharp front which separates reactants from less dense products. In this type of plume, entrainment assists the reaction, producing new buoyancy which fuels an accelerating plume head. When the head has grown to a critical size, it detaches from the upwelling conduit, forming an accelerating, buoyant vortex ring. This vortex is analogous to a rising smoke ring. A second-generation head then develops at the point of detachment.Multiple generations of chemical vortex rings can detach from a single triggering event.

  12. Chemical durability of zircon

    International Nuclear Information System (INIS)

    Zircon (ZrSiO4) exhibits a strong structural affinity for uranium and thorium together with a very high chemical durability. This makes it a potential crystalline host matrix to immobilize actinides issued from separation of nuclear wastes. Irradiation induces amorphization of the crystalline structure (the metamictization process) and thus may decrease the chemical durability of the material. Leaching tests have been conducted on natural zircons from Brazil and Madagascar at 96 deg. C for a period of 1 month, using deionized water. Leachates have been analysed by inductively coupled plasma mass spectrometry (ICP-MS) and UV-visible spectrophotometry. Zircon solid surfaces have been investigated by coupling scanning electron microscopy and X-ray microanalysis (SEM-EDX) with nuclear microprobe analysis (μPIXE, μRBS and μERDA). From the mass balance between leachates and hydrated surfaces, the probable mechanisms of zircon aqueous alteration are presented and discussed

  13. Interactive Chemical Reactivity Exploration

    CERN Document Server

    Haag, Moritz P; Bosson, Mael; Redon, Stephane; Reiher, Markus

    2014-01-01

    Elucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black-box search methods to find intermediates and transition-state structures might fail in such situations because of the high-dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist's intuition into the search process. We employ a haptic pointer device with force-feedback to allow the operator the direct manipulation of structures in three dimensions along with simultaneous perception of the quantum mechanical response upon structure modification as forces. We elaborate on the details of how such an interactive exploration should proceed and which technical difficulties need to be overcome. All reactivity-exploration concepts developed for this purpose have been implemented in the Samson programming environment.

  14. Chemical inhomogeneities and pulsation

    OpenAIRE

    Turcotte, S.

    2001-01-01

    Major improvements in models of chemically peculiar stars have been achieved in the past few years. With these new models it has been possible to test quantitatively some of the processes involved in the formation of abundance anomalies and their effect on stellar structure. The models of metallic A (Am) stars have shown that a much deeper mixing has to be present to account for observed abundance anomalies. This has implications on their variability, which these models also reproduce qualita...

  15. Irish Chemical News

    OpenAIRE

    Franklin, Margaret; Hobbs, Patrick; Hodnett, Kieran; Coleman, Simon; Florea, Larisa; Diamond, Dermot; Nolan, Hugo; Keyes, Tia E.; Thébault, Jean-Pierre; Martin, Patrick; Wall, Jane

    2016-01-01

    Contents: Obituary: Dr Paraic James -- Chemical Sensing with Autonomous Devices in Remote Locations: Why is it so difficult and how do we deliver revolutionary improvements in performance? -- Sensitizing Polyoxometalate Photochemistry for Photoelectrochemical Applications -- Paris Agreement: Developing clean technologies for a better future. -- Protecting Endangered Elements Report -- DCU’s New “Water Institute” -- Dioxin/PCB Analysis by High Resolution Gas Chromatography Mass Spectrometry...

  16. Micromachined chemical jet dispenser

    Energy Technology Data Exchange (ETDEWEB)

    Swierkowski, S.; Ciarlo, D.

    1996-05-13

    Goal is to develop a multi-channel micromachined chemical fluid jet dispenser that is applicable to prototype tests with biological samples that demonstrate its utility for molecular biology experiments. Objective is to demonstrate a new device capable of ultrasonically ejecting droplets from 10-200 {mu}m diameter capillaries that are arranged in an array that is linear or focused. The device is based on several common fabrication procedures used in MEMS (micro electro mechanical systems) technology: piezoelectric actuators, silicon, etc.

  17. Chemical transport reactions

    CERN Document Server

    Schäfer, Harald

    2013-01-01

    Chemical Transport Reactions focuses on the processes and reactions involved in the transport of solid or liquid substances to form vapor phase reaction products. The publication first offers information on experimental and theoretical principles and the transport of solid substances and its special applications. Discussions focus on calculation of the transport effect of heterogeneous equilibria for a gas motion between equilibrium spaces; transport effect and the thermodynamic quantities of the transport reaction; separation and purification of substances by means of material transport; and

  18. Chemical release module facility

    Science.gov (United States)

    Reasoner, D. L.

    1980-01-01

    The chemical release module provides the capability to conduct: (1) thermite based metal vapor releases; (2) pressurized gas releases; (3) dispersed liquid releases; (4) shaped charge releases from ejected submodules; and (5) diagnostic measurements with pi supplied instruments. It also provides a basic R-F and electrical system for: (1) receiving and executing commands; (2) telemetering housekeeping data; (3) tracking; (4) monitoring housekeeping and control units; and (5) ultrasafe disarming and control monitoring.

  19. Chemical product dictionary

    International Nuclear Information System (INIS)

    This book deals with synthetic rubber in the first part: Poly norbornene rubber, Polysulfide rubber, FKM, Fluoridated rubber, BR, CR, Syndiotactic 1,2 - Polybutadiene, Silicone rubber, IR, IIR, ACM, Liquid rubber, SBR, EVA, Co, NBR, TPE, SBC, TPVC, TPO, TPU, TPAE, TPEE, Urethane rubber, CSM, and propylene oxide rubber. The second part describes organic rubber chemical carbon black, processing aid, zinc salts of fatty acids, Exton L-2, Exton k-1, and vulcanizing agent.

  20. Control of chemical chaos

    Institute of Scientific and Technical Information of China (English)

    李卫东; 钱积新

    2002-01-01

    Lyapunov exponents can act as the judgment rule whether the systems is chaotic or not.We propose an approach to control chaotic systems by varying the Lyapunov exponents of the system. At last we use this method to control a chemical system. Both the theoretical analysis and the simulation results prove that this method can quickly and effectively stabilize the chaotic systems to the desire points.

  1. Chemical sensor system

    Science.gov (United States)

    Darrach, Murray R. (Inventor); Chutjian, Ara (Inventor)

    2008-01-01

    A chemical sensing apparatus and method for the detection of sub parts-per-trillion concentrations of molecules in a sample by optimizing electron utilization in the formation of negative ions is provided. A variety of media may be sampled including air, seawater, dry sediment, or undersea sediment. An electrostatic mirror is used to reduce the kinetic energy of an electron beam to zero or near-zero kinetic energy.

  2. Chemical constituents of Asparagus

    Directory of Open Access Journals (Sweden)

    J S Negi

    2010-01-01

    Full Text Available Asparagus species (family Liliaceae are medicinal plants of temperate Himalayas. They possess a variety of biological properties, such as being antioxidants, immunostimulants, anti-inflammatory, antihepatotoxic, antibacterial, antioxytocic, and reproductive agents. The article briefly reviews the isolated chemical constituents and the biological activities of the plant species. The structural formula of isolated compounds and their distribution in the species studied are also given.

  3. Miniature Chemical Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Andrew C. R. Pipino

    2004-12-13

    A new chemical detection technology has been realized that addresses DOE environmental management needs. The new technology is based on a variant of the sensitive optical absorption technique, cavity ring-down spectroscopy (CRDS). Termed evanescent-wave cavity ring-down spectroscopy (EW-CRDS), the technology employs a miniature solid-state optical resonator having an extremely high Q-factor as the sensing element, where the high-Q is achieved by using ultra-low-attenuation optical materials, ultra-smooth surfaces, and ultra-high reflectivity coatings, as well as low-diffraction-loss designs. At least one total-internal reflection (TIR) mirror is integral to the resonator permitting the concomitant evanescent wave to probe the ambient environment. Several prototypes have been designed, fabricated, characterized, and applied to chemical detection. Moreover, extensions of the sensing concept have been explored to enhance selectivity, sensitivity, and range of application. Operating primarily in the visible and near IR regions, the technology inherently enables remote detection by optical fiber. Producing 11 archival publications, 5 patents, 19 invited talks, 4 conference proceedings, a CRADA, and a patent-license agreement, the project has realized a new chemical detection technology providing >100 times more sensitivity than comparable technologies, while also providing practical advantages.

  4. Equiseparable chemical trees

    Directory of Open Access Journals (Sweden)

    BORIS FURTULA

    2003-07-01

    Full Text Available Let n1(e|T and n2(e|T denote the number of vertices of a tree T, lying on the two sides of the edge e. Let T1 and T2 be two trees with equal number of vertices, let e be an edge of T1 and f an edge of T2. Then e and f are said to be equiseparable if either n1(e|T1 = n1(e|T2 or n1(e|T1 = n2(e|T2. If all edges of T1 and T2 can be chosen so as to form equiseparable pairs, then T1 and T2 are equiseparable trees. A number of molecular structure-descriptors of equiseparable chemical trees coincide, implying that the corresponding alkane isomers must have similar physico-chemical properties. It is shown how equiseparable chemical trees can be constructed in a systematic manner.

  5. Chemical Education in Bulgaria

    Science.gov (United States)

    Garkov, Vladimir N.

    1999-08-01

    The sociopolitical changes in Eastern Europe of the 1990s and the ongoing globalization of the chemical industry and chemical education prompted this analysis of the current status of chemical education in Bulgaria, which is not very different from the educational practices in the rest of Europe. The level of chemistry knowledge expected from all high-school graduates in Bulgaria is roughly equivalent to the general and organic chemistry courses for science majors at U.S. universities. The newly introduced four-year bachelor's degree curriculum (based on 15-week semesters) at the University of Sofia includes a core of 106 semester hours (labs counted as 1 hour each), 41 semester hours of electives, and 445 contact hours (11 weeks) of research, which ends with a thesis defense. The instructional techniques in Bulgaria are subject-centered and follow the hierarchical structure of knowledge in an integrated and unitary manner. In conclusion, the Bulgarian system of education in chemistry aims at preparing a scientifically literate citizenry and broadly trained chemists by imposing a very challenging and rigid curriculum with very few choices. It is speculated that the laissez-faire climate of free intellectual initiative seen only at American universities provides a more appropriate environment for talent encouragement and scientific innovation for overseas-educated undergraduate and graduate students than their home institutions.

  6. Chemical Abstracts Service Chemical Registry System: History, Scope, and Impacts.

    Science.gov (United States)

    Weisgerber, David W.

    1997-01-01

    Describes the history, scope, and applications of the Chemical Abstracts Service Chemical Registry System, a computerized database that uniquely identifies chemical substances on the basis of their molecular structures. Explains searching the system is and discusses its use as an international resource. (66 references) (Author/LRW)

  7. Chemical Agents: Facts about Evacuation

    Science.gov (United States)

    ... Health Emergency Response Guide Reaching At-Risk Populations Chemical Agents: Facts About Evacuation Format: Select one PDF [ ... on Facebook Tweet Share Compartir Some kinds of chemical accidents or attacks, such as a train derailment ...

  8. Chemical Explosion Database

    Science.gov (United States)

    Johansson, Peder; Brachet, Nicolas

    2010-05-01

    A database containing information on chemical explosions, recorded and located by the International Data Center (IDC) of the CTBTO, should be established in the IDC prior to entry into force of the CTBT. Nearly all of the large chemical explosions occur in connection with mining activity. As a first step towards the establishment of this database, a survey of presumed mining areas where sufficiently large explosions are conducted has been done. This is dominated by the large coal mining areas like the Powder River (U.S.), Kuznetsk (Russia), Bowen (Australia) and Ekibastuz (Kazakhstan) basins. There are also several other smaller mining areas, in e.g. Scandinavia, Poland, Kazakhstan and Australia, with large enough explosions for detection. Events in the Reviewed Event Bulletin (REB) of the IDC that are located in or close to these mining areas, and which therefore are candidates for inclusion in the database, have been investigated. Comparison with a database of infrasound events has been done as many mining blasts generate strong infrasound signals and therefore also are included in the infrasound database. Currently there are 66 such REB events in 18 mining areas in the infrasound database. On a yearly basis several hundreds of events in mining areas have been recorded and included in the REB. Establishment of the database of chemical explosions requires confirmation and ground truth information from the States Parties regarding these events. For an explosion reported in the REB, the appropriate authority in whose country the explosion occurred is encouraged, on a voluntary basis, to seek out information on the explosion and communicate this information to the IDC.

  9. Advanced Chemical Propulsion

    Science.gov (United States)

    Alexander, L.

    2004-11-01

    Improving the performance and reliability characteristics of chemical propulsion systems requires research and testing of higher-performance propellants, higher efficiency thrusters, cryogenics technology, lightweight components and advancements in propulsion system design and assessment. Propellants are being investigated to identify practical combinations with higher efficiencies and better thermal properties to reduce thermal control requirements. This includes combinations with modest increases, such as LOX-hydrazine, as well as a new evaluation of major improvements available from fluorine-bearing oxidizers. Practical ways of implementing cryogenic propulsion to further increase efficiency are also being studied. Some potential advances include small pump-fed engines, and improvements in cryocooler technology and tank pressure control. Gelled propellants will be tested to determine the practicality of letting propellants freeze at low environmental temperatures and thawing them only when required for use. The propellant tank is typically the single highest non-expendable mass in a chemical propulsion system. Lightweight tank designs, materials and methods of fabrication are being investigated. These are projected to offer a 45-50 percent decrease in tank mass, representing the potential inert system mass savings. Mission and systems analyses are being conducted to guide the technology research and set priorities for technology investment, based on estimated gains in payload and mission capabilities. This includes development of advanced assessment tools and analyses of specific missions selected from Science Missions' Directorate. The goal is to mature a suite of reliable advanced propulsion technologies that will promote more cost efficient missions through the reduction of interplanetary trip time, increased scientific payload mass fraction and longer on-station operations. This talk will review the Advanced Chemical technology development roadmap, current

  10. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2007-01-01

    SAVO BRATOS, Laboratoire de Physique The´orique des Liquides Universite´ Pierre et Marie Curie, 75252 Paris Cedex, France MARK S. CHILD, Physical and Theoretical Chemistry Laboratory, Oxford University, Oxford, 0X1 3QZ, United Kingdom EVELYN M. GOLDFIELD, Department of Chemistry, Wayne State University of Michigan, 48202 USA STEPHEN K. GRAY, Chemistry Division, Argonne National Laboratory, Illinois 60439 USA VASSILIY LUBCHENKO, Department of Chemistry, University of Houston, Houston, Texas 77204-5003 USA G. ALI MANSOORI, Departments of Biology and Chemical Engineering, University of

  11. Lasers in chemical processing

    International Nuclear Information System (INIS)

    The high cost of laser energy is the crucial issue in any potential laser-processing application. It is expensive relative to other forms of energy and to most bulk chemicals. We show those factors that have previously frustrated attempts to find commercially viable laser-induced processes for the production of materials. Having identified the general criteria to be satisfied by an economically successful laser process and shown how these imply the laser-system requirements, we present a status report on the uranium laser isotope separation (LIS) program at the Lawrence Livermore National Laboratory

  12. Chemical evolution of galaxies

    International Nuclear Information System (INIS)

    Initial conditions are probably set by results of Big Bang nucleosynthesis (BBNS) without intervening complications affecting the composition of visible matter so that extrapolation of observed abundances to BBNS products seems fairly secure. Primordial helium and deuterium abundances deduced in this way place upper and lower limits on baryonic density implying that both baryonic and non-baryonic dark matter exist and predicting no more than 3 neutrino flavours as recently confirmed in accelerator experiments. The validity of simple galactic chemical evolution models assumed in extrapolating back to the Big Bang is examined in the light of the frequency distribution of iron or oxygen abundances in the Galactic halo, bulge and disk. (orig.)

  13. Chemical modifiers of radiotherapy

    International Nuclear Information System (INIS)

    Only two groups, anticancer drugs and radiosensitizers are discussed among many groups of chemical modifiers. In combined radiotherapy (RT) with chemotherapy (CT), sequential administration seems to be superior to concomitant administration, because simultaneous use enhances intensively normal tissue damage. In sequential administration, interruption of CT during RT causes growth of distant metastases. So, alternating scheme of RT and CT is proposed and evaluated clinically. Hypoxic cell sensitizers including well-known misonidazole and PLDR inhibitors (Ara-A etc.) are promising in radiotherapy. They should be used intermittently two or three times during RT in order to avoid neurotoxicity of misonidazole. (author) 70 refs

  14. LLNL Chemical Kinetics Modeling Group

    Energy Technology Data Exchange (ETDEWEB)

    Pitz, W J; Westbrook, C K; Mehl, M; Herbinet, O; Curran, H J; Silke, E J

    2008-09-24

    The LLNL chemical kinetics modeling group has been responsible for much progress in the development of chemical kinetic models for practical fuels. The group began its work in the early 1970s, developing chemical kinetic models for methane, ethane, ethanol and halogenated inhibitors. Most recently, it has been developing chemical kinetic models for large n-alkanes, cycloalkanes, hexenes, and large methyl esters. These component models are needed to represent gasoline, diesel, jet, and oil-sand-derived fuels.

  15. The Use of Chemical-Chemical Interaction and Chemical Structure to Identify New Candidate Chemicals Related to Lung Cancer

    OpenAIRE

    Chen, Lei; Yang, Jing; Zheng, Mingyue; Kong, Xiangyin; Huang, Tao; Cai, Yu-Dong

    2015-01-01

    Lung cancer causes over one million deaths every year worldwide. However, prevention and treatment methods for this serious disease are limited. The identification of new chemicals related to lung cancer may aid in disease prevention and the design of more effective treatments. This study employed a weighted network, constructed using chemical-chemical interaction information, to identify new chemicals related to two types of lung cancer: non-small lung cancer and small-cell lung cancer. Then...

  16. Stochastic processes in chemical physics

    CERN Document Server

    Shuler, K E

    2009-01-01

    The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.

  17. Chemical evolution in hierarchical scenarios

    OpenAIRE

    Tissera P.B.

    2012-01-01

    We studied the chemical properties of Milky-Way mass galaxies. We found common global chemical patterns with particularities which reflect their different assembly histories in a hierarchical scenario. We carried out a comprehensively analysis of the dynamical components (central spheroid, disc, inner and outer haloes) and their chemical properties.

  18. The chemical ecology of cyanobacteria

    OpenAIRE

    Pedro N. Leão; Engene, Niclas; Antunes, Agostinho; Gerwick, William H; Vasconcelos, Vitor

    2012-01-01

    This review covers the literature on the chemically mediated ecology of cyanobacteria, including ultraviolet radiation protection, feeding-deterrence, allelopathy, resource competition, and signalling. To highlight the chemical and biological diversity of this group of organisms, evolutionary and chemotaxonomical studies are presented. Several technologically relevant aspects of cyanobacterial chemical ecology are also discussed.

  19. Modern Chemical Technology, Volume 5.

    Science.gov (United States)

    Pecsok, Robert L., Ed.; Chapman, Kenneth, Ed.

    This volume contains chapters 26-31 for the American Chemical Society (ACS) "Modern Chemical Technology" (ChemTeC) instructional material intended to prepare chemical technologists. Chapter 26 reviews oxidation and reduction, including applications in titrations with potassium permanganate and iodometry. Coordination compounds are described in the…

  20. Green chemistry for chemical synthesis

    OpenAIRE

    Li, Chao-Jun; Trost, Barry M.

    2008-01-01

    Green chemistry for chemical synthesis addresses our future challenges in working with chemical processes and products by inventing novel reactions that can maximize the desired products and minimize by-products, designing new synthetic schemes and apparati that can simplify operations in chemical productions, and seeking greener solvents that are inherently environmentally and ecologically benign.

  1. Green chemistry for chemical synthesis

    Science.gov (United States)

    Li, Chao-Jun; Trost, Barry M.

    2008-01-01

    Green chemistry for chemical synthesis addresses our future challenges in working with chemical processes and products by inventing novel reactions that can maximize the desired products and minimize by-products, designing new synthetic schemes and apparati that can simplify operations in chemical productions, and seeking greener solvents that are inherently environmentally and ecologically benign. PMID:18768813

  2. Wearable Optical Chemical Sensors

    Science.gov (United States)

    Lobnik, Aleksandra

    Wearable sensors can be used to provide valuable information about the wearer's health and/or monitor the wearer's surroundings, identify safety concerns and detect threats, during the wearer's daily routine within his or her natural environment. The "sensor on a textile", an integrated sensor capable of analyzing data, would enable early many forms of detection. Moreover, a sensor connected with a smart delivery system could simultaneously provide comfort and monitoring (for safety and/or health), non-invasive measurements, no laboratory sampling, continuous monitoring during the daily activity of the person, and possible multi-parameter analysis and monitoring. However, in order for the technology to be accessible, it must remain innocuous and impose a minimal intrusion on the daily activities of the wearer. Therefore, such wearable technologies should be soft, flexible, and washable in order to meet the expectations of normal clothing. Optical chemical sensors (OCSs) could be used as wearable technology since they can be embedded into textile structures by using conventional dyeing, printing processes and coatings, while fiber-optic chemical sensors (FOCSs) as well as nanofiber sensors (NFSs) can be incorporated by weaving, knitting or laminating. The interest in small, robust and sensitive sensors that can be embedded into textile structures is increasing and the research activity on this topic is an important issue.

  3. Chemical simulation of greywater.

    Science.gov (United States)

    Abed, Suhail Najem; Scholz, Miklas

    2016-01-01

    Sustainable water resources management attracts considerable attention in today's world. Recycling and reuse of both wastewater and greywater are becoming more attractive. The strategy is to protect ecosystem services by balancing the withdrawal of water and the disposal of wastewater. In the present study, a timely and novel synthetic greywater composition has been proposed with respect to the composition of heavy metals, nutrients and organic matter. The change in water quality of the synthetic greywater due to increasing storage time was monitored to evaluate the stability of the proposed chemical formula. The new greywater is prepared artificially using analytical-grade chemicals to simulate either low (LC) or high (HC) pollutant concentrations. The characteristics of the synthetic greywater were tested (just before starting the experiment, after two days and a week of storage under real weather conditions) and compared to those reported for real greywater. Test results for both synthetic greywater types showed great similarities with the physiochemical properties of published findings concerning real greywater. Furthermore, the synthetic greywater is relatively stable in terms of its characteristics for different storage periods. However, there was a significant (p change was also noted for the reduction (70%) of nitrate-nitrogen (NO3-N) concerning HC greywater after seven days of storage. PMID:26745659

  4. Radiometric chemical analysis

    International Nuclear Information System (INIS)

    The radiometric method of analysis is noted for its sensitivity and its simplicity in both apparatus and procedure. A few inexpensive radioactive reagents permit the analysis of a wide variety of chemical elements and compounds. Any particular procedure is generally applicable over a very wide range of concentrations. It is potentially an analytical method of great industrial significance. Specific examples of analyses are cited to illustrate the potentialities of ordinary equipment. Apparatus specifically designed for radiometric chemistry may shorten the time required, and increase the precision and accuracy for routine analyses. A sensitive and convenient apparatus for the routine performance of radiometric chemical analysis is a special type of centrifuge which has been used in obtaining the data presented in this paper. The radioactivity of the solution is measured while the centrifuge is spinning. This device has been used as the basis for an automatic analyser for phosphate ion, programmed to follow a sequence of unknown sampling, reagent mixing, centrifugation, counting data presentation, and phosphate replenishment. This analyser can repeatedly measure phosphate-concentration in the range of 5 to 50 ppm with an accuracy of ±5%. (author)

  5. Remanufacturing strategy for chemical equipment

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-cheng; XU Bin-shi; WANG Hai-dou; JIANG Yi; WU Yi-xiong; GONG Jian-ming; TU Shan-dong

    2005-01-01

    Failure, especially induced by cracks, usually occurred in the service process of chemical equipment, which could cause the medium leakage, fire hazard and explosion and induced the personnel casualty and economic losses. To assure the long-term and safety service, it is necessary to apply the remanufacturing technology on the chemical equipment containing cracks. The recent research advances on the remanufacturing, the failure modes and the life extension technology for chemical equipment were reviewed. The engineering strategy of the remanufacturing for the chemical equipment was proposed, which could provide a reasonable and reliable technical route for the remanufacturing operation of chemical equipment. In the strategy, the redesign was also been considered.

  6. Chemical contamination of material cycles

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Astrup, Thomas Fruergaard

    2015-01-01

    chemicals, which would be re‐introduced into the loop once a product is recycled. Such chemicals may not be removed in the recycling process, persist, and contaminate the newly manufactured products. Chemical contamination could potentially put product consumers at unnecessary risk and jeopardize public......) chemicals in paper and plastic materials, and furthermore discuss the likely impacts of chemical contamination on material recycling. The work is part of the new Danish initiative focusing on Integrated Resource Management and Recovery (IRMAR, grant no. 11‐116775). The outcomes of the work will provide...

  7. CO2 chemical valorization

    International Nuclear Information System (INIS)

    Facing global warming, different technological solutions exist to tackle carbon dioxide (CO2) emissions. Some inevitable short term emissions can be captured so as to avoid direct emissions into the atmosphere. This CO2 must then be managed and geological storage seems to currently be the only way of dealing with the large volumes involved. However, this solution faces major economic profitability and societal acceptance challenges. In this context, alternative pathways consisting in using CO2 instead of storing it do exist and are generating growing interest. This study ordered by the French Environment and Energy Management Agency (ADEME), aims at taking stock of the different technologies used for the chemical conversion of CO2 in order to have a better understanding of their development potential by 2030, of the conditions in which they could be competitive and of the main actions to be implemented in France to foster their emergence. To do this, the study was broken down into two main areas of focus: The review and characterization of the main CO2 chemical conversion routes for the synthesis of basic chemical products, energy products and inert materials. This review includes a presentation of the main principles underpinning the studied routes, a preliminary assessment of their performances, advantages and drawbacks, a list of the main R and D projects underway, a focus on emblematic projects as well as a brief analysis of the markets for the main products produced. Based on these elements, 3 routes were selected from among the most promising by 2030 for an in-depth modelling and assessment of their energy, environmental and economic performances. The study shows that the processes modelled do have favorable CO2 balances (from 1 to 4 t-CO2/t-product) and effectively constitute solutions to reduce CO2 emissions, despite limited volumes of CO2 in question. Moreover, the profitability of certain solutions will remain difficult to reach, even with an energy mix

  8. Solar chemical heat pipe

    International Nuclear Information System (INIS)

    The performance of a solar chemical heat pipe was studied using CO2 reforming of methane as a vehicle for storage and transport of solar energy. The endothermic reforming reaction was carried out in an Inconel reactor, packed with a Rh catalyst. The reactor was suspended in an insulated box receiver which was placed in the focal plane of the Schaeffer Solar Furnace of the Weizman Institute of Science. The exothermic methanation reaction was run in a 6-stage adiabatic reactor filled with the same Rh catalyst. Conversions of over 80% were achieved for both reactions. In the closed loop mode the products from the reformer and from the metanator were compressed into separate storage tanks. The two reactions were run either separately or 'on-line'. The complete process was repeated for over 60 cycles. The overall performance of the closed loop was quite satisfactory and scale-up work is in progress in the Solar Tower. (authors). 35 refs., 2 figs

  9. Cracking a chemical conundrum

    Energy Technology Data Exchange (ETDEWEB)

    Adams, James M.; Ivanov, Alexandre S.; Johnson, Mark R.; Stride, John A

    2004-07-15

    An everyday laboratory chemical, hexamethylbenzene (HMB) has assumed an important role in the history of molecular structure and crystallography. It was one of the first organic crystal structures to be solved and provided direct experimental proof for the hypothesis of planarity in aromatic systems. Very soon after this, HMB was found to undergo a phase transition at 117 K, resulting in crystal shattering. Since then, many attempts have been made to obtain the low-temperature structure, but none have succeeded until now. Making use of the unique properties of the neutron, we have performed powder diffraction measurements to obtain the low-temperature crystal structure and inelastic measurements to determine the dynamics of the system. These experiments have been augmented by the use of ab initio calculations and molecular modelling to obtain a complete picture of HMB in the solid state.

  10. Modeling in Chemical Engineering

    Directory of Open Access Journals (Sweden)

    Jaap van Brakel

    2000-10-01

    Full Text Available Models underlying the use of similarity considerations, dimensionless numbers, and dimensional analysis in chemical engineering are discussed. Special attention is given to the many levels at which models and ceteris paribus conditions play a role and to the modeling of initial and boundary conditions. It is shown that both the laws or dimensionless number correlations and the systems to which they apply are models. More generally, no matter which model or description one picks out, what is being modeled is itself a model of something else. Instead of saying that the artifact S models the given B, it is therefore better to say that S and B jointly make up B and S.

  11. [Chemical and electrical burns].

    Science.gov (United States)

    Sanchez, Raymond

    2002-12-15

    Chemical burns are less frequent in routine practice, but could be very serious owing to the complexity and severity of their actions. Influx of casualty after a civil disaster (industrial explosion) or military (war or terrorism) is possible. The action of these agents could be prolonged and deep. In addition to the skin, respiratory lesions and general intoxication could be observed. The urgent local treatment rely essentially on prolonged washing. Prevention and adequate emergency care could limit the serious consequences of these accidents. Accidents (thermal burns or electrisations) due to high or low voltage electricity are frequent. The severity is linked with the affected skin but especially with internal lesions, muscular, neurological or cardiac lesions. All cases of electrisation need hospital care. Locally, the lesions are often deep with difficult surgical repairs and often require amputation. Aesthetic and functional sequela are therefore frequent. Secondary complications could appear several months after the accident: cataract, dysesthesia and hypotonia. PMID:12621941

  12. Chemical properties of mendelevium

    International Nuclear Information System (INIS)

    Even with the most intense ion beams and the largest available quantities of target isotope, about 106 atoms at a time is all the Md that can be produced for chemical studies. This lack of sufficient sample size coupled with the very short lifetimes of the few atoms produced has severely restricted the gathering and the broadness of our knowledge concerning the properties of Md and the heavier elements. To illustrate, the literature contains a mere eleven references to the chemical studies of Md, and none of these deal with bulk properties associated with the element bound in solid phases. Some of these findings are: Md was found to be more volatile than other actinide metals which lead to the belief that it is divalent in the metallic state; separation of Md from the other actinides can be accomplished either by reduction of Md3+ to the divalent state or by chromatographic separations with Md remaining in the tripositive state; extraction of Md2+ with bis(2-ethylhexyl)phosphoric acid is much poorer than the extraction of the neighboring tripositive actinides; attempts to oxidize Md3+ with sodium bismuthate failed to show any evidence for Md4+; reduction potential of Md3+ was found to be close to -0.1 volt; Md3+ can be reduced to Md(Hg) by sodium amalgams and by electrolysis; the electrochemical behavior of Md is very similar to that of Fm and can be summarized in the equation, Md2+ + 2e- = Md(Hg) and E0 = -1.50 V.; and Md cannot be reduced to a monovalent ion with Sm2+

  13. Inducible chemical defences in animals

    OpenAIRE

    Heyttyey, Attila; Tóth, Zoltán; Buskirk, Josh

    2014-01-01

    Phenotypic plasticity is extremely widespread in the behaviour, morphology and life-history of animals. However, inducible changes in the production of defensive chemicals are described mostly in plants and surprisingly little is known about similar plasticity in chemical defences of animals. Inducible chemical defences may be common in animals because many are known to produce toxins, the synthesis of toxins is likely to be costly, and there are a few known cases of animals adjusting their t...

  14. Errors in Chemical Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Artur Dybko

    2001-06-01

    Full Text Available Various types of errors during the measurements of ion-selective electrodes, ionsensitive field effect transistors, and fibre optic chemical sensors are described. The errors were divided according to their nature and place of origin into chemical, instrumental and non-chemical. The influence of interfering ions, leakage of the membrane components, liquid junction potential as well as sensor wiring, ambient light and temperature is presented.

  15. Wearable bio and chemical sensors

    OpenAIRE

    Coyle, Shirley; Curto, Vincenzo; Benito-Lopez, Fernando; Florea, Larisa; Diamond, Dermot

    2014-01-01

    Chemical and biochemical sensors have experienced tremendous growth in the past decade due to advances in material chemistry combined with the emergence of digital communication technologies and wireless sensor networks (WSNs) [1]. The emergence of wearable chemical and biochemical sensors is a relatively new concept that poses unique challenges to the field of wearable sensing. This is because chemical sensors have a more complex mode of operation, compared to physical transducers, in that t...

  16. Perfect Actions with Chemical Potential

    CERN Document Server

    Bietenholz, W

    1998-01-01

    We show how to include a chemical potential \\mu in perfect lattice actions. It turns out that the standard procedure of multiplying the quark fields \\Psi, an example, the case of free fermions with chemical potential is worked out explicitly. Even after truncation, cut-off effects in the pressure and the baryon density are small. Using a (quasi-)perfect action, numerical QCD simulations for non-zero chemical potential become more powerful, because coarse lattices are sufficient for extracting continuum physics.

  17. Chemical interaction between undamaged plants

    OpenAIRE

    Glinwood, Robert; Ninkovic, Velemir; Pettersson, Jan

    2011-01-01

    Most research on plant–plant chemical interactions has focussed on events following herbivore or pathogen attack. However, undamaged plants also interact chemically as a natural facet of their behaviour, and this may have consequences for insects that use the plants as hosts. In this review, the links between allelopathy and insect behaviour are outlined. Findings on how chemical interactions between different plant species and genotypes affect aphid herbivores and their natural e...

  18. Introduction to chemical reaction engineering

    International Nuclear Information System (INIS)

    This deals with chemical reaction engineering with thirteen chapters. The contents of this book are introduction on reaction engineering, chemical kinetics, thermodynamics and chemical reaction, abnormal reactor, non-isothermal reactor, nonideal reactor, catalysis in nonuniform system, diffusion and reaction in porosity catalyst, design catalyst heterogeneous reactor in solid bed, a high molecule polymerization, bio reaction engineering, reaction engineering in material process, control multi-variable reactor process using digital computer.

  19. Chemical Stockpile Disposal Program

    Energy Technology Data Exchange (ETDEWEB)

    Krummel, J.R.; Policastro, A.J.; Olshansky, S.J.; McGinnis, L.D.

    1990-10-01

    As part of the Chemical Stockpile Disposal Program mandated by Public Law 99--145 (Department of Defense Authorization Act), an independent review is presented of the US Army Phase I environmental report for the disposal program at the Umatilla Depot Activity (UMDA) in Hermiston, Oregon. The Phase I report addressed new and additional concerns not incorporated in the final programmatic environmental impact statement (FPEIS). Those concerns were addressed by examining site-specific data for the Umatilla Depot Activity and by recommending the scope and content of a more detailed site-specific study. This independent review evaluates whether the new site-specific data presented in the Phase I report would alter the decision in favor of on-site disposal that was reached in the FPEIS, and whether the recommendations for the scope and content of the site-specific study are adequate. Based on the methods and assumptions presented in the FPEIS, the inclusion of more detailed site-specific data in the Phase I report does not change the decision reached in the FPEIS (which favored on-site disposal at UMDA). It is recommended that alternative assumptions about meteorological conditions be considered and that site-specific data on water, ecological, socioeconomic, and cultural resources; seismicity; and emergency planning and preparedness be considered explicitly in the site-specific EIS decision-making process. 7 refs., 1 fig.

  20. Chemical compounds in teak

    Directory of Open Access Journals (Sweden)

    Fernanda Viana da Silva Leonardo

    2015-09-01

    Full Text Available Quinone compounds are largely generated at extractive fraction of the woods in a complex and variable biological system. The literature has indications for many segments from food industry to pharmaceutical industry. Within the field of industrial use of wood, they are less desirable since they are treated only as incidental substances in production strings of pulp, paper, charcoal, and sawmill. In spite of its small amount, compared to other chemical compounds called essential, these substances have received special attention from researchers revealing a diverse range of offerings to market products textiles, pharmaceuticals, colorants, and other polymers, for which are being tested and employed. Quinones are found in fungi, lichens, and mostly in higher plants. Tectona grandis, usually called teak, is able to biosynthesize anthraquinones, which is a quinone compound, byproduct of secondary metabolism. This species provides wood that is much prized in the furniture sector and can also be exploited for metabolites to supply the market in quinone compounds and commercial development of new technologies, adding value to the plantations of this species within our country.

  1. Theory of Chemical Modeling

    Science.gov (United States)

    Kühn, Michael

    In order to deal with the complexity of natural systems simplified models are employed to illustrate the principal and regulatory factors controlling a chemical system. Following the aphorism of Albert Einstein: Everything should be made as simple as possible, but not simpler, models need not to be completely realistic to be useful (Stumm and Morgan 1996), but need to meet a successful balance between realism and practicality. Properly constructed, a model is neither too simplified that it is unrealistic nor too detailed that it cannot be readily evaluated and applied to the problem of interest (Bethke 1996). The results of a model have to be at least partially observable or experimentally verifiable (Zhu and Anderson 2002). Geochemical modeling theories are presented here in a sequence of increasing complexity from geochemical equilibrium models to kinetic, reaction path, and finally coupled transport and reaction models. The description is far from complete but provides the needs for the set up of reactive transport models of hydrothermal systems as done within subsequent chapters. Extensive reviews of geochemical models in general can be found in the literature (Appelo and Postma 1999, Bethke 1996, Melchior and Bassett 1990, Nordstrom and Ball 1984, Paschke and van der Heijde 1996).

  2. Chemical Synthesis of Copper Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hamid Reza Ghorbani

    2014-06-01

    Full Text Available Metal nanoparticles have attracted considerable interest particularly because of the size dependence of physical and chemical properties and its enormous technological potential. Among different metal nanoparticles, copper nanoparticles have attracted great attention because copper is one of the most key metals in new technology. Chemical methods are used to synthesize copper nanoparticles and among them chemical reduction is the most frequently applied method for the preparation of stable, colloidal dispersions in organic solvents. In this paper, a brief overview of the current research worldwide in the chemical synthesis of copper nanoparticles is discussed.

  3. Chemical substructure analysis in toxicology

    International Nuclear Information System (INIS)

    A preliminary examination of chemical-substructure analysis (CSA) demonstrates the effective use of the Chemical Abstracts compound connectivity file in conjunction with the bibliographic file for relating chemical structures to biological activity. The importance of considering the role of metabolic intermediates under a variety of conditions is illustrated, suggesting structures that should be examined that may exhibit potential activity. This CSA technique, which utilizes existing large files accessible with online personal computers, is recommended for use as another tool in examining chemicals in drugs. 2 refs., 4 figs

  4. Fundamentals of chemical reaction engineering

    CERN Document Server

    Davis, Mark E

    2012-01-01

    Appropriate for a one-semester undergraduate or first-year graduate course, this text introduces the quantitative treatment of chemical reaction engineering. It covers both homogeneous and heterogeneous reacting systems and examines chemical reaction engineering as well as chemical reactor engineering. The authors take a chemical approach, helping students develop an intuitive feeling for concepts, rather than an engineering approach, which tends to overlook the inner workings of systems and objects.Each chapter contains numerous worked-out problems and real-world vignettes involving commercia

  5. Chemical substructure analysis in toxicology

    Energy Technology Data Exchange (ETDEWEB)

    Beauchamp, R.O. Jr. [Center for Information on Toxicology and Environment, Raleigh, NC (United States)

    1990-12-31

    A preliminary examination of chemical-substructure analysis (CSA) demonstrates the effective use of the Chemical Abstracts compound connectivity file in conjunction with the bibliographic file for relating chemical structures to biological activity. The importance of considering the role of metabolic intermediates under a variety of conditions is illustrated, suggesting structures that should be examined that may exhibit potential activity. This CSA technique, which utilizes existing large files accessible with online personal computers, is recommended for use as another tool in examining chemicals in drugs. 2 refs., 4 figs.

  6. Chemical Physics Electrons and Excitations

    CERN Document Server

    Larsson, Sven

    2012-01-01

    A full understanding of modern chemistry is impossible without quantum theory. Since the advent of quantum mechanics in 1925, a number of chemical phenomena have been explained, such as electron transfer, excitation energy transfer, and other phenomena in photochemistry and photo-physics. Chemical bonds can now be accurately calculated with the help of a personal computer. Addressing students of theoretical and quantum chemistry and their counterparts in physics, Chemical Physics: Electrons and Excitations introduces chemical physics as a gateway to fields such as photo physics, solid-state ph

  7. Simulations of chemical catalysis

    Science.gov (United States)

    Smith, Gregory K.

    This dissertation contains simulations of chemical catalysis in both biological and heterogeneous contexts. A mixture of classical, quantum, and hybrid techniques are applied to explore the energy profiles and compare possible chemical mechanisms both within the context of human and bacterial enzymes, as well as exploring surface reactions on a metal catalyst. A brief summary of each project follows. Project 1 - Bacterial Enzyme SpvC The newly discovered SpvC effector protein from Salmonella typhimurium interferes with the host immune response by dephosphorylating mitogen-activated protein kinases (MAPKs) with a beta-elimination mechanism. The dynamics of the enzyme substrate complex of the SpvC effector is investigated with a 3.2 ns molecular dynamics simulation, which reveals that the phosphorylated peptide substrate is tightly held in the active site by a hydrogen bond network and the lysine general base is positioned for the abstraction of the alpha hydrogen. The catalysis is further modeled with density functional theory (DFT) in a truncated active-site model at the B3LYP/6-31 G(d,p) level of theory. The truncated model suggested the reaction proceeds via a single transition state. After including the enzyme environment in ab initio QM/MM studies, it was found to proceed via an E1cB-like pathway, in which the carbanion intermediate is stabilized by an enzyme oxyanion hole provided by Lys104 and Tyr158 of SpvC. Project 2 - Human Enzyme CDK2 Phosphorylation reactions catalyzed by kinases and phosphatases play an indispensable role in cellular signaling, and their malfunctioning is implicated in many diseases. Ab initio quantum mechanical/molecular mechanical studies are reported for the phosphoryl transfer reaction catalyzed by a cyclin-dependent kinase, CDK2. Our results suggest that an active-site Asp residue, rather than ATP as previously proposed, serves as the general base to activate the Ser nucleophile. The corresponding transition state features a

  8. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

    Full Text Available Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions is a transition from batch to continuous processes. However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat and mass transfer and narrow residence time distribution. The oscillatory flow reactors (OFR are newer type of tube reactors which can offer solution by providing continuous operation with approximately plug flow pattern, low shear stress rates and enhanced mass and heat transfer. These benefits are the result of very good mixing in OFR achieved by vortex generation. OFR consists of cylindrical tube containing equally spaced orifice baffles. Fluid oscillations are superimposed on a net (laminar flow. Eddies are generated when oscillating fluid collides with baffles and passes through orifices. Generation and propagation of vortices create uniform mixing in each reactor cavity (between baffles, providing an overall flow pattern which is close to plug flow. Oscillations can be created by direct action of a piston or a diaphragm on fluid (or alternatively on baffles. This article provides an overview of oscillatory flow reactor technology, its operating principles and basic design and scale - up characteristics. Further, the article reviews the key research findings in heat and mass transfer, shear stress, residence time distribution in OFR, presenting their advantages over the conventional reactors. Finally, relevant process intensification examples from pharmaceutical, polymer and biofuels industries are presented.

  9. Reduction of chemical reaction models

    Science.gov (United States)

    Frenklach, Michael

    1991-01-01

    An attempt is made to reconcile the different terminologies pertaining to reduction of chemical reaction models. The approaches considered include global modeling, response modeling, detailed reduction, chemical lumping, and statistical lumping. The advantages and drawbacks of each of these methods are pointed out.

  10. Mathematical Modeling of Chemical Stoichiometry

    Science.gov (United States)

    Croteau, Joshua; Fox, William P.; Varazo, Kristofoland

    2007-01-01

    In beginning chemistry classes, students are taught a variety of techniques for balancing chemical equations. The most common method is inspection. This paper addresses using a system of linear mathematical equations to solve for the stoichiometric coefficients. Many linear algebra books carry the standard balancing of chemical equations as an…

  11. Chemical Evolution in Omega Centauri

    OpenAIRE

    Smith, Verne V.

    2003-01-01

    The globular cluster Omega Centauri displays evidence of a complex star formation history and peculiar internal chemical evolution, setting it apart from essentially all other globular clusters of the Milky Way. In this review we discuss the nature of the chemical evolution that has occurred within Omega Cen and attempt to construct a simple scenario to explain its chemistry.

  12. Chemical Compatibility of Polymeric Materials.

    Science.gov (United States)

    Solen, Kenneth A.; Kuchar, Marvin C.

    1990-01-01

    Presents some principles for specifying general classes of polymers for predicting relative chemical attack from acids, bases, oxidants, and certain common antagonists. Also discusses predicting relative solvent effects. Suggests uses of this information in two or three lectures in a chemical engineering materials course. (YP)

  13. Chemical and natural stressors combined:

    DEFF Research Database (Denmark)

    Gergs, André; Zenker, Armin; Grimm, Volker;

    2013-01-01

    In addition to natural stressors, populations are increasingly exposed to chemical pollutants released into the environment. We experimentally demonstrate the loss of resilience for Daphnia magna populations that are exposed to a combination of natural and chemical stressors even though effects o...

  14. Imprinted photonic crystal chemical sensors

    NARCIS (Netherlands)

    Boersma, A.; Burghoorn, M.M.A.; Saalmink, M.

    2011-01-01

    In this paper we present the use of Photonic Crystals as chemical sensors. These 2D nanostructured sensors were prepared by nano-imprint lithography during which a nanostructure is transferred from a nickel template into a responsive polymer, that is be specifically tuned to interact with the chemic

  15. Chemical Gel for Surface Decontamination

    International Nuclear Information System (INIS)

    Many chemical decontamination processes operate by immersing components in aggressive chemical solutions. In these applications chemical decontamination technique produce large amounts of radioactive liquid waste. Therefore it is necessary to develop processes using chemical gels instead of chemical solutions, to avoid the well-known disadvantages of chemical decontamination techniques while retaining their high efficiency. Chemical gels decontamination process consists of applying the gel by spraying it onto the surface of large area components (floors, walls, etc) to be decontaminated. The gel adheres to any vertical or complex surface due to their thixotropic properties and operates by dissolving the radioactive deposit, along with a thin layer of the gel support, so that the radioactivity trapped at the surface can be removed. Important aspects of the gels are that small quantities can be used and they show thixitropic properties : liquid during spraying, and solid when stationary, allowing for strong adherence to surfaces. This work investigates the decontamination behaviors of organic-based chemical gel for SS 304 metallic surfaces contaminated with radioactive materials

  16. Teaching Chemical Engineers about Teaching

    Science.gov (United States)

    Heath, Daniel E.; Hoy, Mary; Rathman, James F.; Rohdieck, Stephanie

    2013-01-01

    The Chemical and Biomolecular Engineering Department at The Ohio State University in collaboration with the University Center for the Advancement of Teaching developed the Chemical Engineering Mentored Teaching Experience. The Mentored Teaching Experience is an elective for Ph.D. students interested in pursuing faculty careers. Participants are…

  17. How to control chemical hazards

    CERN Multimedia

    2012-01-01

    Improving protection against chemical hazards is one of the 2012 CERN safety objectives identified by the Director General. Identifying and drawing up a complete inventory of chemicals, and assessing the associated risks are important steps in this direction.   The HSE Unit has drawn up safety rules, guidelines and forms to help you to meet this objective. We would like to draw your attention to: • safety guidelines C-0-0-1 and C-1-0-2 (now also available in French), which deal with the identification of hazardous chemicals and the assessment of chemical risk; • safety guideline C-1-0-1, which deals with the storage of hazardous chemicals. All safety documents can be consulted at: cern.ch/regles-securite The HSE Unit will be happy to answer any questions you may have. Write to us at: safety-general@cern.ch The HSE Unit

  18. Chemical mechanisms of the interaction between radiation and chemical carcinogens

    International Nuclear Information System (INIS)

    There is evidence to suggest that ionizing radiation and chemical carcinogens can act synergistically to produce deleterious biological effects. In addition, many carcinogens undergo metabolic activation in vivo. This activation, initiated by biochemical redox reactions, can be simulated chemically, electrochemically, photochemically and radiation chemically. The principal reactive species formed by the action of ionizing radiation on aqueous solutions of macromolecules and mammalian cells, are hydroxyl radicals and superoxide anions. Pulse and steady-state radiolysis studies of model chemical systems have established that these species can 'activate' chemical carcinogens by a radical oxidation process, and that the resulting activated carcinogens can subsequently react with nucleophilic sites on DNA and other potential target macromolecules. Rate constants for some of the fast reactions involved in the radiation activation of carcinogens and in the subsequent carcinogen-DNA interactions have been determined, together with the yields of radiation-induced covalent DNA-carcinogen binding. A redox models for radiation-induced chemical carcinogenesis is proposed which describes a possible mechanism of action involving free radical species generated in the aqueous cellular milieu, which diffuse to and react with carcinogens located within the micro-environment of the cell. Preliminary experiments suggest that protection against radiation and chemical carcinogenesis can be achieved by radical scavenging or by competitive free radical inhibition

  19. Chemical Mapping of Vesta

    Science.gov (United States)

    Prettyman, Thomas H.; Mittlefehldt, D. W.; Yamashita, N.; Lawrence, D. J.; Beck, A. W.; McSween, H. Y.; Feldman, W. C.; McCoy, T. J.; Titus, T. N.; Toplis, M. J.; Reedy, R. C.; Forni, O.; Mizzon, H.; Peplowski, P. N.; Raymond, C. A.; Russell, C. T.

    2012-01-01

    Vesta s surface mineralogy and composition have been studied for decades via telescopic spectroscopy and laboratory analyses of the howardite, eucrite, and diogenite (HED) meteorites, which are thought to originate from Vesta. Visible and infrared reflectance measurements by Dawn have broadly confirmed the paradigm established by Earth-based work, strengthening the Vesta-HED connection. The Dawn mission has achieved a milestone by completing the first chemical measurements of a main-belt asteroid using nuclear spectroscopy. Dawn s Gamma Ray and Neutron Detector (GRaND) has globally mapped the composition of Vesta, including the portions of the northern hemisphere not illuminated by solar radiation. GRaND is sensitive to the composition of the bulk regolith to depths of several decimeters. Abundances and/or detection limits for specific elements and elemental ratios, such as H, Fe, Si, Fe/O, Fe/Si, and K, have been measured. Variations in the average atomic mass and neutron macroscopic absorption cross section have been characterized. The measurements constrain the relative proportions of HED whole-rock end-members, providing measurements of the pyroxene and plagioclase content of the regolith, thereby constraining the processes underlying Vesta s differentiation and crustal evolution. The spatial resolution of GRaND is sufficient to determine basin-average compositions of Veneneia and Rheasilvia, which may contain outcrops of Vesta s olivine-rich mantle. While the elemental composition of Vesta s regolith is similar to the meteorites, there are notable departures from HED whole-rock compositions. While these differences are not sufficient to topple the Vesta-HED paradigm, they provide insight into global-scale processes that have shaped Vesta s surface. Questions addressed by the analysis of GRaND data include: (i) Is Vesta the source of the Fe-rich mesosiderites? (ii) Are evolved, igneous lithologies present on Vesta s surface? (iii) What are the origins of

  20. Chemical Force Microscopy of Chemical and Biological Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Noy, A

    2006-01-02

    Interactions between chemical functionalities define outcomes of the vast majority of important events in chemistry, biology and materials science. Chemical Force Microscopy (CFM)--a technique that uses direct chemical functionalization of AFM probes with specific functionalities--allows researchers to investigate these important interactions directly. We review the basic principles of CFM, some examples of its application, and theoretical models that provide the basis for understanding the experimental results. We also emphasize application of modern kinetic theory of non-covalent interactions strength to the analysis of CFM data.

  1. Chemical cleaning, decontamination and corrosion

    International Nuclear Information System (INIS)

    Chemical cleaning of process equipments and pipings in chemical/petrochemical industries is necessitated for improving operation, for preventing premature failures and for avoiding contamination. In developing a chemical formulation for cleaning equipments, the important aspects to be considered include (i) effective removal of corrosion products and scales, (ii) minimum corrosion of the base metal, (iii) easy to handle chemicals and (iv) economic viability. As on date, a wide variety of chemical formulations are available, many of them are either proprietory or patented. For evolving an effective formulation, knowledge of the oxides of various metals and alloys on the one hand and acid concentration, complexing agents and inhibitors to be incorporated on the other, is quite essential. Organic acids like citric acid, acetic acid and formic acid are more popular ones, often used with EDTA for effective removal of corrosion products from ferrous components. The report enumerates some of the concepts in developing effective formulations for chemical cleaning of carbon steel components and further, makes an attempt to suggest simple formulations to be developed for chemical decontamination. (author). 6 refs., 3 fi gs., 4 tabs

  2. Chemical munitions dumped at sea

    Science.gov (United States)

    Edwards, Margo; Bełdowski, Jacek

    2016-06-01

    Modern chemical warfare is a byproduct of the industrial revolution, which created factories capable of rapidly producing artillery shells that could be filled with toxic chemicals such as chlorine, phosgene and mustard agent. The trench warfare of World War I inaugurated extensive deployments of modern chemical weapons in 1915. Concomitantly, the need arose to dispose of damaged, captured or excess chemical munitions and their constituents. Whereas today chemical warfare agents (CWA) are destroyed via chemical neutralization processes or high-temperature incineration in tandem with environmental monitoring, in the early to middle 20th century the options for CWA disposal were limited to open-air burning, burial and disposal at sea. The latter option was identified as the least likely of the three to impact mankind, and sea dumping of chemical munitions commenced. Eventually, the potential impacts of sea dumping human waste were recognized, and in 1972 an international treaty, the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, was developed to protect the marine environment from pollution caused by the dumping of wastes and other matter into the ocean. By the time this treaty, referred to as the London Convention, was signed by a majority of nations, millions of tons of munitions were known to have been disposed throughout the world's oceans.

  3. [Acute and subacute chemical pneumonitis].

    Science.gov (United States)

    Andujar, P; Nemery, B

    2009-10-01

    Acute or subacute chemical-induced lung injury is rarely compound specific and is most often caused by an accidental occupational, domestic or environmental exposure to an inhaled chemical agent. The industrial disaster that happened in Bhopal in 1984, accidental poisoning with chlorine and petroleum hydrocarbons and also vesicant gases used during conflicts, are specific examples. Rarely, a chemical agent can cause lung damage by being ingested and reaching the lung through the systemic circulation (for example accidental or deliberate paraquat ingestion). Household accidents should not be underestimated. An important cause of household accidents is chlorine inhalation resulting from mixing bleach with acids such as the scale removers used to clean toilets. Chemical agents can provoke direct and/or indirect damage to the respiratory tract. The acute or subacute clinical manifestations resulting from inhalation of chemical agents are very varied and include inhalation fevers, acute non-cardiogenic pulmonary oedema, adult respiratory distress syndrome, reactive airways dysfunction syndrome and acute or subacute pneumonitis. The site and the severity of chemical-induced respiratory damage caused by inhaled chemical agents depend mainly on the nature and the amount of the agent inhaled. The immediate and long-term prognosis and possible sequelae are also variable. This review excludes infectious or immunologically induced acute respiratory diseases. PMID:19953031

  4. Chemical detection of buried landmines

    Energy Technology Data Exchange (ETDEWEB)

    Phelan, J.M.; Webb, S.W.

    1998-03-01

    Of all the buried landmine identification technologies currently available, sensing the chemical signature from the explosive components found in landmines is the only technique that can classify non-explosive objects from the real threat. In the last two decades, advances in chemical detection methods has brought chemical sensing technology to the foreground as an emerging technological solution. In addition, advances have been made in the understanding of the fundamental transport processes that allow the chemical signature to migrate from the buried source to the ground surface. A systematic evaluation of the transport of the chemical signature from inside the mine into the soil environment, and through the soil to the ground surface is being explored to determine the constraints on the use of chemical sensing technology. This effort reports on the results of simulation modeling using a one-dimensional screening model to evaluate the impacts on the transport of the chemical signature by variation of some of the principal soil transport parameters.

  5. Coulometry in quantitative chemical analysis and physico-chemical research

    International Nuclear Information System (INIS)

    Electroanalytical methods such as potentiometry, amperometry, coulometry and voltammetry are well established and routinely employed in quantitative chemical analysis as well as in chemical research. Coulometry is one of the most important electroanalytical techniques, which involves change in oxidation state of electro active species by heterogeneous electron transfer. In primary coulometric method, uranium is determined at mercury pool electrode and plutonium at platinum gauze electrode

  6. Assimilating chemical compound with a regional chemical model

    Science.gov (United States)

    Chang, C.; Yang, S.; Liang, M.; Hsu, S.; Tseng, Y.

    2012-12-01

    To constrain the source and sink of the chemical compounds at surface during model simulation, chemical compound assimilation with Local Ensemble Transform Kalman Filter (LETKF) has been implemented for the WRF-ChemT model. In this study, a two-tier system is applied to assimilating the meteorological and chemical variables in an OSSE framework. The unobserved surface flux is estimated according to the observations in the chemical component. A long-term nature run with total constant emission of 5.3×108 g/s is assumed to be the truth state in the OSSE. The simulated observations are obtained from the truth state by adding random errors. In order to generate the initial CO2 ensembles with similar spatial distribution as truth state without other prior information, the initial perturbation fields of CO2 are randomly chosen from three long-term runs with different emissions. The results indicate that in the constant emission case, the system can successfully estimate the unobserved chemical forcing and improve the distribution of the chemical compound. Under the scenario of diurnal forcing induced by human activities, the problem in estimating surface flux becomes more complex and difficult. A set of experiments with different initial chemical states suggest that the estimation of flux is sensitive to the quality of initial CO2 and CO2 surface flux. Strategies are designed to retrieve the time-varying information. The results show that with time-varying information and reliable initial ensembles, the estimation of surface flux have been significantly improved. Couple assimilation with meteorological and chemical components Surface flux estimation

  7. Chemical microreactor and method thereof

    Energy Technology Data Exchange (ETDEWEB)

    Morse, Jeffrey D. (Martinez, CA); Jankowski, Alan (Livermore, CA)

    2011-08-09

    A method for forming a chemical microreactor includes forming at least one capillary microchannel in a substrate having at least one inlet and at least one outlet, integrating at least one heater into the chemical microreactor, interfacing the capillary microchannel with a liquid chemical reservoir at the inlet of the capillary microchannel, and interfacing the capillary microchannel with a porous membrane near the outlet of the capillary microchannel, the porous membrane being positioned beyond the outlet of the capillary microchannel, wherein the porous membrane has at least one catalyst material imbedded therein.

  8. Selected readings in chemical kinetics

    CERN Document Server

    Back, Margaret H

    2013-01-01

    Selected Readings in Chemical Kinetics covers excerpts from 12 papers in the field of general and gas-phase kinetics. The book discusses papers on the laws of connexion between the conditions of a chemical change and its amount; on the reaction velocity of the inversion of the cane sugar by acids; and the calculation in absolute measure of velocity constants and equilibrium constants in gaseous systems. The text then tackles papers on simple gas reactions; on the absolute rate of reactions in condensed phases; on the radiation theory of chemical action; and on the theory of unimolecular reacti

  9. Chemical processing of lunar materials

    Science.gov (United States)

    Criswell, D. R.; Waldron, R. D.

    1979-01-01

    The paper highlights recent work on the general problem of processing lunar materials. The discussion covers lunar source materials, refined products, motivations for using lunar materials, and general considerations for a lunar or space processing plant. Attention is given to chemical processing through various techniques, including electrolysis of molten silicates, carbothermic/silicothermic reduction, carbo-chlorination process, NaOH basic-leach process, and HF acid-leach process. Several options for chemical processing of lunar materials are well within the state of the art of applied chemistry and chemical engineering to begin development based on the extensive knowledge of lunar materials.

  10. DNA adducts-chemical addons

    OpenAIRE

    T. R. Rajalakshmi; N AravindhaBabu; Shanmugam, K. T.; Masthan, K. M. K.

    2015-01-01

    DNA adduct is a piece of DNA covalently bond to a chemical (safrole, benzopyrenediol epoxide, acetaldehyde). This process could be the start of a cancerous cell. When a chemical binds to DNA, it gets damaged resulting in abnormal replication. This could be the start of a mutation and without proper DNA repair, this can lead to cancer. It is this chemical that binds with the DNA is our prime area of concern. Instead of performing the whole body analysis for diagnosing cancer, this test could b...

  11. Chemical treatment of radioactive wastes

    International Nuclear Information System (INIS)

    This is the third manual of three commissioned by the IAEA on the three principal techniques used in concentrating radioactive liquid wastes, namely chemical precipitation, evaporation and ion exchange. The present manual deals with chemical precipitation by coagulation-flocculation and sedimentation, commonly called ''chemical treatment'' of low-activity wastes. Topics discussed in the manual are: (i) principles of coagulation on flocculation and sedimentation and associated processes; (ii) process and equipment; (iii) conditioning and disposal of flocculation sludge; (iv) sampling and the equipment required for experiments; and (v) factors governing the selection of processes. 99 refs, 17 figs, 4 tabs

  12. The handling of chemical data

    CERN Document Server

    Lark, P D; Bosworth, R C L

    1968-01-01

    The Handling of Chemical Data deals with how measurements, such as those arrived at from chemical experimentation, are handled. The book discusses the different kinds of measurements and their specific dimensional characteristics by starting with the origin and presentation of chemical data. The text explains the units, fixed points, and relationships found between scales, the concept of dimensions, the presentation of quantitative data (whether in a tabular or graphical form), and some uses of empirical equations. The book also explains the relationship between two variables, and how equatio

  13. The chemical industry of Ukraine

    International Nuclear Information System (INIS)

    This work deals with the chemical industry of Ukraine and more particularly with the restructuring proposed by the Ministry of Industry. After having presented some generalities the author focuses on the restructuring programme which includes the improvement of the fertilizers supply for agriculture, the development of facilities for basic organic synthesis, the increase of petroleum based chemicals production, the increase of consumer products production and the reorientation of the chemical industry to more accessible and alternative sources of raw materials such as black and brown coal, oil shale, coke, oil-refining gases, plant raw materials... (O.L.)

  14. Improved Optical Fiber Chemical Sensors

    Science.gov (United States)

    Egalon, Claudio O.; Rogowski, Robert S.

    1994-01-01

    Calculations, based on exact theory of optical fiber, have shown how to increase optical efficiency sensitivity of active-core, step-index-profile optical-fiber fluorosensor. Calculations result of efforts to improve efficiency of optical-fiber chemical sensor of previous concept described in "Making Optical-Fiber Chemical Sensors More Sensitive" (LAR-14525). Optical fiber chemical detector of enhanced sensitivity made in several configurations. Portion of fluorescence or chemiluminescence generated in core, and launched directly into bound electromagnetic modes that propagate along core to photodetector.

  15. Computer Simulation in Chemical Kinetics

    Science.gov (United States)

    Anderson, Jay Martin

    1976-01-01

    Discusses the use of the System Dynamics technique in simulating a chemical reaction for kinetic analysis. Also discusses the use of simulation modelling in biology, ecology, and the social sciences, where experimentation may be impractical or impossible. (MLH)

  16. Chemical Evolution of Protostellar Matter

    Science.gov (United States)

    Langer, William D.; vanDishoeck, Ewine F.; Bergin, Edwin A.; Blake, Geoffrey A.; Tielens, Alexander G. G. M.; Velusamy, Thangasamy; Whittet, Douglas C. B.

    2000-01-01

    We review the chemical processes that are important in the evolution from a molecular cloud core to a protostellar disk. These cover both gas phase and gas grain interactions. The current observational and theoretical state of this field are discussed.

  17. Programmability of Chemical Reaction Networks

    Science.gov (United States)

    Cook, Matthew; Soloveichik, David; Winfree, Erik; Bruck, Jehoshua

    Motivated by the intriguing complexity of biochemical circuitry within individual cells we study Stochastic Chemical Reaction Networks (SCRNs), a formal model that considers a set of chemical reactions acting on a finite number of molecules in a well-stirred solution according to standard chemical kinetics equations. SCRNs have been widely used for describing naturally occurring (bio)chemical systems, and with the advent of synthetic biology they become a promising language for the design of artificial biochemical circuits. Our interest here is the computational power of SCRNs and how they relate to more conventional models of computation. We survey known connections and give new connections between SCRNs and Boolean Logic Circuits, Vector Addition Systems, Petri nets, Gate Implementability, Primitive Recursive Functions, Register Machines, Fractran, and Turing Machines. A theme to these investigations is the thin line between decidable and undecidable questions about SCRN behavior.

  18. Chemical basis for minimal cognition

    DEFF Research Database (Denmark)

    Hanczyc, Martin; Ikegami, Takashi

    We have developed a simple chemical system capable of self-movement in order to study the chemical-molecular origins of movement, perception and cognition. The system consists simply of an oil droplet in an aqueous environment. The aqueous phase contains a surfactant that modulates the interfacial...... tension between the drop of oil and its environment. We embed a chemical reaction in the oil phase that reacts with water when an oily precursor comes in contact with the water phase at the liquidliquid interface. This reaction not only powers the droplet to move in the aqueous phase but also allows for...... convection flow is generated inside the oil droplet to cause the movement, which was also confirmed by simulating the fluid dynamics integrated with chemical reactions (Matsuno et al., 2007, ACAL 07, Springer, p.179, Springer). We can observe that the droplet senses the gradient in the environment (either...

  19. Chemical Specific Adjustment Factors Workshop

    Science.gov (United States)

    The World Health Organization, through the International Programme on Chemical Safety (IPCS), has established guidance on the use of mechanistic data to replace default uncertainty factors for interspecies extrapolation and intraspecies variability in deriving risk values such as...

  20. Introduction to Galactic Chemical Evolution

    CERN Document Server

    Matteucci, Francesca

    2016-01-01

    In this lecture I will introduce the concept of galactic chemical evolution, namely the study of how and where the chemical elements formed and how they were distributed in the stars and gas in galaxies. The main ingredients to build models of galactic chemical evolution will be described. They include: initial conditions, star formation history, stellar nucleosynthesis and gas flows in and out of galaxies. Then some simple analytical models and their solutions will be discussed together with the main criticisms associated to them. The yield per stellar generation will be defined and the hypothesis of instantaneous recycling approximation will be critically discussed. Detailed numerical models of chemical evolution of galaxies of different morphological type, able to follow the time evolution of the abundances of single elements, will be discussed and their predictions will be compared to observational data. The comparisons will include stellar abundances as well as interstellar medium ones, measured in galax...

  1. Hydrophobic interactions and chemical reactivity

    OpenAIRE

    Otto, Sijbren; Engberts, Jan B.F.N.

    2003-01-01

    This perspective describes how kinetic studies of organic reactions can be used to increase our understanding of hydrophobic interactions. In turn, our understanding of hydrophobic interactions can be used as a tool to influence chemical reactions.

  2. Chemical Production using Fission Fragments

    International Nuclear Information System (INIS)

    Some reactor design considerations of the use of fission recoil fragment energy for the production of chemicals of industrial importance have been discussed previously in a paper given at the Second United Nations International Conference on the Peaceful Uses of Atomic Energy [A/Conf. 15/P.76]. The present paper summarizes more recent progress made on this topic at AERE, Harwell. The range-energy relationship for fission fragments is discussed in the context of the choice of fuel system for a chemical production reactor, and the experimental observation of a variation of chemical effect along the length of a fission fragment track is described for the irradiation of nitrogen-oxygen mixtures. Recent results are given on the effect of fission fragments on carbon monoxide-hydrogen gas mixtures and on water vapour. No system investigated to date shows any outstanding promise for large-scale chemical production. (author)

  3. The chemical ecology of copepods

    DEFF Research Database (Denmark)

    Heuschele, Jan; Selander, Erik

    2014-01-01

    An increasing number of studies show the importance of chemical interactions in the aquatic environment. Our understanding of the role of chemical cues and signals in larger crustaceans has advanced in the last decades. However, for copepods, the most abundant metazoan zooplankton and essential for...... the functioning of the marine food web, much is still unknown. We synthesize current knowledge about chemical ecology of copepods including foraging, survival and reproduction. We also compile information on the sensory apparatus and new analytical approaches that may facilitate the identification of...... signal molecules. The review illustrates the importance of chemical interactions in many aspects of copepod ecology and identifies gaps in our knowledge, such as the lack of identified infochemicals and electrophysiological studies to confirm the function of sensory structures. We suggest approaches that...

  4. Microprocessors in automatic chemical analysis

    International Nuclear Information System (INIS)

    Application of microprocessors to programming and computing of solutions chemical analysis by a sequential technique is examined. Safety, performances reliability are compared to other methods. An example is given on uranium titration by spectrophotometry

  5. Mass-sensitive chemical preconcentrator

    Science.gov (United States)

    Manginell, Ronald P.; Adkins, Douglas R.; Lewis, Patrick R.

    2007-01-30

    A microfabricated mass-sensitive chemical preconcentrator actively measures the mass of a sample on an acoustic microbalance during the collection process. The microbalance comprises a chemically sensitive interface for collecting the sample thereon and an acoustic-based physical transducer that provides an electrical output that is proportional to the mass of the collected sample. The acoustic microbalance preferably comprises a pivot plate resonator. A resistive heating element can be disposed on the chemically sensitive interface to rapidly heat and release the collected sample for further analysis. Therefore, the mass-sensitive chemical preconcentrator can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  6. Monitoring presence of chemical agents

    International Nuclear Information System (INIS)

    The specification describes a case for use with a hand-portable chemical agent detector for continuously monitoring an atmosphere for the presence of predetermined chemical agents. The detector having means for ionizing air samples and providing at an output terminal electrical signals representative of the mobility spectrum of ionized chemical vapours produced by the ionizing means. The case comprises means for defining a chamber in the case for supporting and removably enclosing the detector, means for communicating ambient atmosphere to the chamber, electrical circuit means in the case, the circuit means being adapted to be detachably connected to the detector output terminal when the detector is positioned in the chamber and being responsive to the electrical signals for producing an alarm signal when the signals detect a chemical agent concentration in the atmosphere exceeding a predetermined concentration level, and alarm means responsive to the alarm signal. (author)

  7. Chemical radioprotectors in radiation protection

    International Nuclear Information System (INIS)

    The different demands for the ways of the administration of chemical radioprotectors as a cystamine or WR-2721 (amifostine, gammaphos, Ethyol) e.g. S-containing compounds, their distribution and further pharmacological properties of protective agents in mentioned indications are discussed in presented lecture. A special attention is concerned on the practical use of chemical radioprotectors in the emergency and clean-up workers after a radiation accident or nuclear catastrophes. (author)

  8. Practical Chemical Thermodynamics for Geoscientists

    CERN Document Server

    Fegley, Jr, Bruce

    2012-01-01

    Practical Chemical Thermodynamics for Geoscientists covers classical chemical thermodynamics and focuses on applications to practical problems in the geosciences, environmental sciences, and planetary sciences. This book will provide a strong theoretical foundation for students, while also proving beneficial for earth and planetary scientists seeking a review of thermodynamic principles and their application to a specific problem. Strong theoretical foundation and emphasis on applicationsNumerous worked examples in each chapterBrief historical summaries and biographies of key thermodynamicist

  9. Stellar Yields and Chemical Evolution

    OpenAIRE

    Gibson, Brad K.

    1997-01-01

    Several speakers at IAU Symposium #187 (Cosmic Chemical Evolution) alluded to the zeroth-order agreement between Type II supernovae (SNe) stellar yield compilations, as predicted by the models of those most responsible for driving progress in the field - i.e., Arnett (1991,1996); Maeder (1992); Woosley & Weaver (1995); Langer & Henkel (1995); Thielemann et al. (1996). It is important though for those entering (or indeed, already involved in!) the chemical evolution field to be cognizant of th...

  10. The ergonomics of chemical control

    International Nuclear Information System (INIS)

    Over the past three years the Palo Verde Nuclear Generating Station has developed and implemented a comprehensive chemical control program. The program encompasses all United States regulatory requirements, industry guidelines, and manufacturer recommendations related to hazardous chemicals for both the compliance groups and employees. More than 35,000 man-hours were expended in the development, implementation, and maintenance of this program. This paper details that effort and outlines the resource allocation and summarizes the lessons learned

  11. China's Chemical Pharmaceutical Industry Rebounding

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ After reorganization in 2006, China's chemical pharmaceutical industry began to pick up in 2007. According to the China Pharmaceutical Industry Association,China's chemical pharmaceutical industry achieved sales revenues of RMB202.5 billion in the first eight months this year, a growth of 24.6% - 5.6 percentage points faster than January to May this year. The net profit was RMB17.4 billion, an increase of 50.8% over the same period of 2006.

  12. Data Disclosure for Chemical Evaluations

    OpenAIRE

    Lutter, Randall; Barrow, Craig; Borgert, Christopher J.; Conrad, James W.; Edwards, Debra; Felsot, Allan

    2012-01-01

    Background: Public disclosure of scientific data used by the government to make regulatory decisions for chemicals is a practical step that can enhance public confidence in the scientific basis of such decisions. Objectives: We reviewed the U.S. Environmental Protection Agency’s (EPA) current practices regarding disclosure of data underlying regulatory and policy decisions involving chemicals, including pesticides. We sought to identify additional opportunities for the U.S. EPA to disclose da...

  13. Chemically enhanced in situ recovery

    Energy Technology Data Exchange (ETDEWEB)

    Sale, T. [CH2M Hill, Denver, CO (United States); Pitts, M.; Wyatt, K. [Surtek, Inc., Golden, CO (United States)] [and others

    1996-08-01

    Chemically enhanced recovery is a promising alternative to current technologies for management of subsurface releases of organic liquids. Through the inclusion of surfactants, solvents, polymers, and/or alkaline agents to a waterflood, the transport of targeted organic compounds can be increased and rates of recovery enhanced. By far, the vast majority of work done in the field of chemically enhanced recovery has been at a laboratory scale. The following text focuses on chemically enhanced recovery from a field application perspective with emphasis given to chlorinated solvents in a low permeability setting. While chlorinated solvents are emphasized, issues discussed are also relevant to organic liquids less dense than water such as petroleum products. Topics reviewed include: (1) Description of technology; (2) General technology considerations; (3) Low permeability media considerations; (4) Cost and reliability considerations; (5) Commercial availability; and (6) Case histories. Through this paper an appreciation is developed of both the potential and limitations of chemically enhanced recovery. Excluded from the scope of this paper is the in situ destruction of organic compounds through processes such as chemical or biological oxidation, chemically enhanced recovery of inorganic compounds, and ex situ soil treatment processes. 11 refs., 2 figs., 1 tab.

  14. Chemical characterization of element 112.

    Science.gov (United States)

    Eichler, R; Aksenov, N V; Belozerov, A V; Bozhikov, G A; Chepigin, V I; Dmitriev, S N; Dressler, R; Gäggeler, H W; Gorshkov, V A; Haenssler, F; Itkis, M G; Laube, A; Lebedev, V Ya; Malyshev, O N; Oganessian, Yu Ts; Petrushkin, O V; Piguet, D; Rasmussen, P; Shishkin, S V; Shutov, A V; Svirikhin, A I; Tereshatov, E E; Vostokin, G K; Wegrzecki, M; Yeremin, A V

    2007-05-01

    The heaviest elements to have been chemically characterized are seaborgium (element 106), bohrium (element 107) and hassium (element 108). All three behave according to their respective positions in groups 6, 7 and 8 of the periodic table, which arranges elements according to their outermost electrons and hence their chemical properties. However, the chemical characterization results are not trivial: relativistic effects on the electronic structure of the heaviest elements can strongly influence chemical properties. The next heavy element targeted for chemical characterization is element 112; its closed-shell electronic structure with a filled outer s orbital suggests that it may be particularly susceptible to strong deviations from the chemical property trends expected within group 12. Indeed, first experiments concluded that element 112 does not behave like its lighter homologue mercury. However, the production and identification methods used cast doubt on the validity of this result. Here we report a more reliable chemical characterization of element 112, involving the production of two atoms of (283)112 through the alpha decay of the short-lived (287)114 (which itself forms in the nuclear fusion reaction of 48Ca with 242Pu) and the adsorption of the two atoms on a gold surface. By directly comparing the adsorption characteristics of (283)112 to that of mercury and the noble gas radon, we find that element 112 is very volatile and, unlike radon, reveals a metallic interaction with the gold surface. These adsorption characteristics establish element 112 as a typical element of group 12, and its successful production unambiguously establishes the approach to the island of stability of superheavy elements through 48Ca-induced nuclear fusion reactions with actinides. PMID:17476264

  15. Chemical characterization of element 112

    Science.gov (United States)

    Eichler, R.; Aksenov, N. V.; Belozerov, A. V.; Bozhikov, G. A.; Chepigin, V. I.; Dmitriev, S. N.; Dressler, R.; Gäggeler, H. W.; Gorshkov, V. A.; Haenssler, F.; Itkis, M. G.; Laube, A.; Lebedev, V. Ya.; Malyshev, O. N.; Oganessian, Yu. Ts.; Petrushkin, O. V.; Piguet, D.; Rasmussen, P.; Shishkin, S. V.; Shutov, A. V.; Svirikhin, A. I.; Tereshatov, E. E.; Vostokin, G. K.; Wegrzecki, M.; Yeremin, A. V.

    2007-05-01

    The heaviest elements to have been chemically characterized are seaborgium (element 106), bohrium (element 107) and hassium (element 108). All three behave according to their respective positions in groups 6, 7 and 8 of the periodic table, which arranges elements according to their outermost electrons and hence their chemical properties. However, the chemical characterization results are not trivial: relativistic effects on the electronic structure of the heaviest elements can strongly influence chemical properties. The next heavy element targeted for chemical characterization is element 112; its closed-shell electronic structure with a filled outer s orbital suggests that it may be particularly susceptible to strong deviations from the chemical property trends expected within group 12. Indeed, first experiments concluded that element 112 does not behave like its lighter homologue mercury. However, the production and identification methods used cast doubt on the validity of this result. Here we report a more reliable chemical characterization of element 112, involving the production of two atoms of 283112 through the alpha decay of the short-lived 287114 (which itself forms in the nuclear fusion reaction of 48Ca with 242Pu) and the adsorption of the two atoms on a gold surface. By directly comparing the adsorption characteristics of 283112 to that of mercury and the noble gas radon, we find that element 112 is very volatile and, unlike radon, reveals a metallic interaction with the gold surface. These adsorption characteristics establish element 112 as a typical element of group 12, and its successful production unambiguously establishes the approach to the island of stability of superheavy elements through 48Ca-induced nuclear fusion reactions with actinides.

  16. Chemical identification and its quality assurance

    CERN Document Server

    Milman, Boris L

    2013-01-01

    Chemical Identification and its Quality Assurance shows how to apply the principles of quality assurance for qualitative chemical analysis. The principles of identification and metrological basics are presented, in addition to the reliability and errors involved with chemical identification.

  17. Overall View of Chemical and Biochemical Weapons

    OpenAIRE

    Vladimír Pitschmann

    2014-01-01

    This article describes a brief history of chemical warfare, which culminated in the signing of the Chemical Weapons Convention. It describes the current level of chemical weapons and the risk of using them. Furthermore, some traditional technology for the development of chemical weapons, such as increasing toxicity, methods of overcoming chemical protection, research on natural toxins or the introduction of binary technology, has been described. In accordance with many parameters, chemical we...

  18. Quantum Entanglement and Chemical Reactivity.

    Science.gov (United States)

    Molina-Espíritu, M; Esquivel, R O; López-Rosa, S; Dehesa, J S

    2015-11-10

    The water molecule and a hydrogenic abstraction reaction are used to explore in detail some quantum entanglement features of chemical interest. We illustrate that the energetic and quantum-information approaches are necessary for a full understanding of both the geometry of the quantum probability density of molecular systems and the evolution of a chemical reaction. The energy and entanglement hypersurfaces and contour maps of these two models show different phenomena. The energy ones reveal the well-known stable geometry of the models, whereas the entanglement ones grasp the chemical capability to transform from one state system to a new one. In the water molecule the chemical reactivity is witnessed through quantum entanglement as a local minimum indicating the bond cleavage in the dissociation process of the molecule. Finally, quantum entanglement is also useful as a chemical reactivity descriptor by detecting the transition state along the intrinsic reaction path in the hypersurface of the hydrogenic abstraction reaction corresponding to a maximally entangled state. PMID:26894237

  19. Chemical decontamination of radioactive waste

    International Nuclear Information System (INIS)

    Radioactive wastes are generated in a number of different kinds of facilities and arise in a wide range of concentrations of radioactive materials and in a variety of physical and chemical forms. There is also a variety of alternatives for treatment and conditioning of the wastes prior disposal. The importance of treatment of radioactive waste for protection of human and environment has long been recognized and considerable experience has gained in this field. Generally, the methods used for treatment of radioactive wastes can be classified into three type's biological, physical and chemical treatment this physical treatment it gives good result than biological treatment. Chemical treatment is fewer hazards and gives good result compared with biological and physical treatments. Chemical treatment is fewer hazards and gives good result compared with biological and physical treatments. In chemical treatment there are different procedures, solvent extraction, ion exchange, electro dialysis but solvent extraction is best one because high purity can be optioned on the other hand the disadvantage that it is expensive. Beside the solvent extraction technique one can be used is ion exchange which gives reasonable result, but requires pretreatment that to avoid in closing of column by colloidal and large species. Electro dialysis technique gives quite result but less than solvent extraction and ion exchange technique the advantage is a cheep.(Author)

  20. Excavation research with chemical explosives

    International Nuclear Information System (INIS)

    The US Army Engineer Nuclear Cratering Group (NCG) is located at the Lawrence Radiation Laboratory in Livermore, California. NCG was established in 1962 and assigned responsibility for technical program direction of the Corps of Engineers Nuclear Excavation Research Program. The major part of the experimental program has been the execution of chemical explosive excavation experiments. In the past these experiments were preliminary to planned nuclear excavation experiments. The experience gained and technology developed in accomplishing these experiments has led to an expansion of NCG's research mission. The overall research and development mission now includes the development of chemical explosive excavation technology to enable the Corps of Engineers to more economically accomplish Civil Works Construction projects of intermediate size. The current and future chemical explosive excavation experiments conducted by NCG will be planned so as to provide data that can be used in the development of both chemical and nuclear excavation technology. In addition, whenever possible, the experiments will be conducted at the specific sites of authorized Civil Works Construction Projects and will be designed to provide a useful portion of the engineering structures planned in that project. Currently, the emphasis in the chemical explosive excavation program is on the development of design techniques for producing specific crater geometries in a variety of media. Preliminary results of two such experiments are described in this paper; Project Pre-GONDOLA III, Phase III, Reservoir Connection Experiment; and a Safety Calibration Series for Project TUGBOAT, a small boat harbor excavation experiment

  1. Scaling up of renewable chemicals.

    Science.gov (United States)

    Sanford, Karl; Chotani, Gopal; Danielson, Nathan; Zahn, James A

    2016-04-01

    The transition of promising technologies for production of renewable chemicals from a laboratory scale to commercial scale is often difficult and expensive. As a result the timeframe estimated for commercialization is typically underestimated resulting in much slower penetration of these promising new methods and products into the chemical industries. The theme of 'sugar is the next oil' connects biological, chemical, and thermochemical conversions of renewable feedstocks to products that are drop-in replacements for petroleum derived chemicals or are new to market chemicals/materials. The latter typically offer a functionality advantage and can command higher prices that result in less severe scale-up challenges. However, for drop-in replacements, price is of paramount importance and competitive capital and operating expenditures are a prerequisite for success. Hence, scale-up of relevant technologies must be interfaced with effective and efficient management of both cell and steel factories. Details involved in all aspects of manufacturing, such as utilities, sterility, product recovery and purification, regulatory requirements, and emissions must be managed successfully. PMID:26874264

  2. Verification of Chemical Weapons Destruction

    International Nuclear Information System (INIS)

    The Chemical Weapons Convention is the only multilateral treaty that bans completely an entire category of weapons of mass destruction under international verification arrangements. Possessor States, i.e. those that have chemical weapons stockpiles at the time of becoming party to the CWC, commit to destroying these. All States undertake never to acquire chemical weapons and not to help other States acquire such weapons. The CWC foresees time-bound chemical disarmament. The deadlines for destruction for early entrants to the CWC are provided in the treaty. For late entrants, the Conference of States Parties intervenes to set destruction deadlines. One of the unique features of the CWC is thus the regime for verifying destruction of chemical weapons. But how can you design a system for verification at military sites, while protecting military restricted information? What degree of assurance is considered sufficient in such circumstances? How do you divide the verification costs? How do you deal with production capability and initial declarations of existing stockpiles? The founders of the CWC had to address these and other challenges in designing the treaty. Further refinement of the verification system has followed since the treaty opened for signature in 1993 and since inspection work was initiated following entry-into-force of the treaty in 1997. Most of this work concerns destruction at the two large possessor States, Russia and the United States. Perhaps some of the lessons learned from the OPCW experience may be instructive in a future verification regime for nuclear weapons. (author)

  3. Chemical basis for minimal cognition.

    Science.gov (United States)

    Hanczyc, Martin M; Ikegami, Takashi

    2010-01-01

    We have developed a simple chemical system capable of self-movement in order to study the physicochemical origins of movement. We propose how this system may be useful in the study of minimal perception and cognition. The system consists simply of an oil droplet in an aqueous environment. A chemical reaction within the oil droplet induces an instability, the symmetry of the oil droplet breaks, and the droplet begins to move through the aqueous phase. The complement of physical phenomena that is then generated indicates the presence of feedback cycles that, as will be argued, form the basis for self-regulation, homeostasis, and perhaps an extended form of autopoiesis. We discuss the result that simple chemical systems are capable of sensory-motor coupling and possess a homeodynamic state from which cognitive processes may emerge. PMID:20586578

  4. Chemical sciences, annual report 1993

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-01

    The Chemical Sciences Division (CSD) is one of eleven research Divisions of the Lawrence Berkeley Laboratory, a DOE National Laboratory. In FY 1993, the Division made considerable progress on developing two end-stations and a beamline to advance combustion dynamics at the Advanced Light Source (ALS). In support of DOE`s national role in combustion research and chemical science, the beamline effort will enable researchers from around the world to make fundamental advances in understanding the structure and reactivity of critical reaction intermediates and transients, and in understanding the dynamics of elementary chemical reactions. The Division has continued to place a strong emphasis on full compliance with environmental health and safety guidelines and regulations and has made progress in technology transfer to industry. Finally, the Division has begun a new program in advanced battery research and development that should help strengthen industrial competitiveness both at home and abroad.

  5. DNA adducts-chemical addons

    Directory of Open Access Journals (Sweden)

    T R Rajalakshmi

    2015-01-01

    Full Text Available DNA adduct is a piece of DNA covalently bond to a chemical (safrole, benzopyrenediol epoxide, acetaldehyde. This process could be the start of a cancerous cell. When a chemical binds to DNA, it gets damaged resulting in abnormal replication. This could be the start of a mutation and without proper DNA repair, this can lead to cancer. It is this chemical that binds with the DNA is our prime area of concern. Instead of performing the whole body analysis for diagnosing cancer, this test could be carried out for early detection of cancer. When scanning tunneling microscope is used, the DNA results can be obtained earlier. DNA adducts in scientific experiments are used as biomarkers.

  6. DNA adducts-chemical addons.

    Science.gov (United States)

    Rajalakshmi, T R; AravindhaBabu, N; Shanmugam, K T; Masthan, K M K

    2015-04-01

    DNA adduct is a piece of DNA covalently bond to a chemical (safrole, benzopyrenediol epoxide, acetaldehyde). This process could be the start of a cancerous cell. When a chemical binds to DNA, it gets damaged resulting in abnormal replication. This could be the start of a mutation and without proper DNA repair, this can lead to cancer. It is this chemical that binds with the DNA is our prime area of concern. Instead of performing the whole body analysis for diagnosing cancer, this test could be carried out for early detection of cancer. When scanning tunneling microscope is used, the DNA results can be obtained earlier. DNA adducts in scientific experiments are used as biomarkers. PMID:26015708

  7. Optimizing Chemical Sensor Array Sizes

    International Nuclear Information System (INIS)

    Optimal selection of array sensors for a chemical sensing application is a nontrivial task. It is commonly believed that ''more is better'' when choosing the number of sensors required to achieve good chemical selectivity. However, cost and system complexity issues point towards the choice of small arrays. A quantitative array optimization is carried out to explore the selectivity of arrays of partially-selective chemical sensors as a function of array size. It is shown that modest numbers (dozens) of target analytes are completely distinguished with a range of arrays sizes. However, the array selectivity and the robustness against sensor sensitivity variability are significantly degraded if the array size is increased above a certain number of sensors, so that relatively small arrays provide the best performance. The results also suggest that data analyses for very large arrays of partially-selective sensors will be optimized by separately anal yzing small sensor subsets

  8. Chemical sciences, annual report 1993

    International Nuclear Information System (INIS)

    The Chemical Sciences Division (CSD) is one of eleven research Divisions of the Lawrence Berkeley Laboratory, a DOE National Laboratory. In FY 1993, the Division made considerable progress on developing two end-stations and a beamline to advance combustion dynamics at the Advanced Light Source (ALS). In support of DOE's national role in combustion research and chemical science, the beamline effort will enable researchers from around the world to make fundamental advances in understanding the structure and reactivity of critical reaction intermediates and transients, and in understanding the dynamics of elementary chemical reactions. The Division has continued to place a strong emphasis on full compliance with environmental health and safety guidelines and regulations and has made progress in technology transfer to industry. Finally, the Division has begun a new program in advanced battery research and development that should help strengthen industrial competitiveness both at home and abroad

  9. Quantum logics and chemical kinetics

    Science.gov (United States)

    Ivanov, C. I.

    1981-06-01

    A statistical theory of chemical kinetics is presented based on the quantum logical concept of chemical observables. The apparatus of Boolean algebra B is applied for the construction of appropriate composition polynomials referring to any stipulated arrangement of the atomic constituents. A physically motivated probability measure μ( F) is introduced on the field B of chemical observables, which considers the occurrence of the yes response of a given F ɛ B. The equations for the time evolution of the species density operators and the master equations for the corresponding number densities are derived. The general treatment is applied to a superposition of elementary substitution reactions (AB) α + C ⇄ (AC) β + B. The expressions for the reaction rate coefficients are established.

  10. Chemical Hygiene and Safety Plan

    Energy Technology Data Exchange (ETDEWEB)

    Berkner, K.

    1992-08-01

    The objective of this Chemical Hygiene and Safety Plan (CHSP) is to provide specific guidance to all LBL employees and contractors who use hazardous chemicals. This Plan, when implemented, fulfills the requirements of both the Federal OSHA Laboratory Standard (29 CFR 1910.1450) for laboratory workers, and the Federal OSHA Hazard Communication Standard (29 CFR 1910.1200) for non-laboratory operations (e.g., shops). It sets forth safety procedures and describes how LBL employees are informed about the potential chemical hazards in their work areas so they can avoid harmful exposures and safeguard their health. Generally, communication of this Plan will occur through training and the Plan will serve as a the framework and reference guide for that training.

  11. Early recognition of chemical dependence.

    Science.gov (United States)

    Maly, R C

    1993-03-01

    Chemical dependence is a leading cause of morbidity and death in the United States. At least 20% of patients seen by primary care physicians in both the outpatient and inpatient setting are chemically dependent. Up to 90% of these patients go undiagnosed by their primary physicians. Chemical dependence is defined as a chronic, progressive illness characterized by the repeated and persistent use of alcohol or drugs despite negative health, family, work, financial, or legal consequences. Primary care physicians are in an ideal position to detect chemical dependence at its earliest stages, when irreversible medical consequences and death are most likely preventable. Alcohol is the most common drug of abuse. Improving the rate of recognition of chemical dependence depends on being familiar with the constellation of physical, mental, and social indicators. Early medical manifestations of alcoholism common in the primary care setting include: gastric complaints, elevated blood pressure, palpitations, traumatic injuries, headaches, impotence, and gout. Early psychosocial manifestations common in both alcohol and drug dependence include anxiety, depression, insomnia, persistent relationship conflicts, work or school problems, and financial or legal problems. Particularly useful laboratory indicators of alcoholism include elevated levels of GGT and MCV, both displaying high specificity, with the GGT level being the most sensitive. Similarly specific laboratory tests for drug dependence are not available. Any patient presenting with any of the above medical, psychosocial, or laboratory manifestations should be screened for chemical dependence. The CAGE questionnaire for alcoholism, a four-question test, is particularly well suited to the primary care setting, where it can be administered in fewer than 60 seconds. The CAGE has demonstrated high sensitivity (in the 80% range) and specificity (approximately 85%) for alcoholism. Comparably convenient instruments do not yet exist

  12. Overseas chemical industry Hand book

    International Nuclear Information System (INIS)

    This book introduces overseas chemical industry, which deals with General chemistry on economic view in the world and prospect and current situation over chemical industry, organic chemistry material on production and demand such as petrochemistry, Energy Supply, Ethylene, Propylene, BTX, Ethylene glycol, Acetaldehyde, Acetic acid, Vinyl Acetate Monomer, PVA, Acrylonitrile, Acrylic esters, Propylene oxide, Propylene Glycol, PPG, Phenol, Acetone, Isopropyl Alcohol, Butanol, Octanol, Methanol, Formalin, Caprolactam Cyclohexane, PTA/DMT, Polyisocyanate, MEK/MIBK, 1.4-BG/THF, Phthalic anhydride and Maleic Anhydride.

  13. Microreactor for fast chemical kinetics

    CERN Document Server

    Baroud, C N; Menetrier, L; Tabeling, P; Baroud, Charles N.; Okkels, Fridolin; Menetrier, Laure; Tabeling, Patrick

    2003-01-01

    The chemical reaction process in a T-shaped microchannel is studied experimentally through the reaction of Ca++ with a fluorescent tracer, Calcium-green. For thin channels (10 um), diffusion of species is found to behave in a way independent of the thickness direction. In such a situation, simulations of a two-dimensional reaction-diffusion model agree remarkably well with the experimental measurements. The comparison of experiments and simulations is used to measure the chemical kinetic constant, which we find to be k=3.2 x 10^5 dm^3/(mol s). Applications of the analysis to faster reactions and to micro-titration are also discussed.

  14. Chemical kinetics and reaction dynamics

    CERN Document Server

    Houston, Paul L

    2006-01-01

    This text teaches the principles underlying modern chemical kinetics in a clear, direct fashion, using several examples to enhance basic understanding. It features solutions to selected problems, with separate sections and appendices that cover more technical applications.Each chapter is self-contained and features an introduction that identifies its basic goals, their significance, and a general plan for their achievement. This text's important aims are to demonstrate that the basic kinetic principles are essential to the solution of modern chemical problems, and to show how the underlying qu

  15. Modeling of turbulent chemical reaction

    Science.gov (United States)

    Chen, J.-Y.

    1995-01-01

    Viewgraphs are presented on modeling turbulent reacting flows, regimes of turbulent combustion, regimes of premixed and regimes of non-premixed turbulent combustion, chemical closure models, flamelet model, conditional moment closure (CMC), NO(x) emissions from turbulent H2 jet flames, probability density function (PDF), departures from chemical equilibrium, mixing models for PDF methods, comparison of predicted and measured H2O mass fractions in turbulent nonpremixed jet flames, experimental evidence of preferential diffusion in turbulent jet flames, and computation of turbulent reacting flows.

  16. Chemical ecology of marine plankton.

    Science.gov (United States)

    Schwartz, Emily R; Poulin, Remington X; Mojib, Nazia; Kubanek, Julia

    2016-07-28

    Covering: January 2013 to online publication December 2014This review summarizes recent research in the chemical ecology of marine pelagic ecosystems, and aims to provide a comprehensive overview of advances in the field in the time period covered. In order to highlight the role of chemical cues and toxins in plankton ecology this review has been organized by ecological interaction types starting with intraspecific interactions, then interspecific interactions (including facilitation and mutualism, host-parasite, allelopathy, and predator-prey), and finally community and ecosystem-wide interactions. PMID:27090772

  17. Chemical Evolution of the Galaxy

    OpenAIRE

    Tosi, M.

    1994-01-01

    Standard models for the chemical evolution of the Galaxy are reviewed with particular emphasis on the history of the abundance gradients in the disk. The effects on the disk structure and metallicity of gas accretion are discussed, showing that a significant fraction of the current disk mass has been accreted in the last Gyrs and that the chemical abundances of the infalling gas can be non primordial but should not exceed 0.3 Z(sun). The distributions with time and with galactocentric distanc...

  18. Recycling and surplus chemical programs

    International Nuclear Information System (INIS)

    In 1988, 45 years of defense production came to a close at the US Department of Energy (DOE) Hanford Site. The mission of the Hanford Site was formally changed to environmental restoration and remediation. Westinghouse Hanford Company (WHC) is the management and operations (M ampersand O) contractor leading the cleanup. Within the framework of future Site cleanup, Hanford recycling and surplus chemical programs are making a viable contribution today to waste minimization, diversion of materials from the waste stream, and setting a standard for future operations. This paper focuses on two successful efforts: paper recycling and surplus chemical sales

  19. Chemical Kinetics on Extrasolar Planets

    CERN Document Server

    Moses, Julianne I

    2013-01-01

    Chemical kinetics plays an important role in controlling the atmospheric composition of all planetary atmospheres, including those of extrasolar planets. For the hottest exoplanets, the composition can closely follow thermochemical-equilibrium predictions, at least in the visible and infrared photosphere at dayside (eclipse) conditions. However, for atmospheric temperatures < ~2000 K, and in the uppermost atmosphere at any temperature, chemical kinetics matters. The two key mechanisms by which kinetic processes drive an exoplanet atmosphere out of equilibrium are photochemistry and transport-induced quenching. We review these disequilibrium processes in detail, discuss observational consequences, and examine some of the current evidence for kinetic processes on extrasolar planets.

  20. Speeding chemical reactions by focusing

    Science.gov (United States)

    Lacasta, A. M.; Ramírez-Piscina, L.; Sancho, J. M.; Lindenberg, K.

    2013-04-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, and obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate ˜t-1/2 to very close to the perfect mixing rate, ˜t-1.

  1. Speeding chemical reactions by focusing

    CERN Document Server

    Lacasta, A M; Sancho, J M; Lindenberg, K

    2012-01-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  2. Chemical patterning in biointerface science

    Directory of Open Access Journals (Sweden)

    Ryosuke Ogaki

    2010-04-01

    Full Text Available Patterning of surfaces with different chemistries provides novel insights into how proteins, cells and tissues interact with materials. New materials, and the properties that their surfaces impart, are highly desirable for the next generation of implants, regenerative medicine and tissue engineering devices, and biosensors and drug delivery devices for disease diagnosis and treatment. Patterning is thus seen as a key technology driver for these materials. We provide an overview of state-of-the-art fabrication tools for creating chemical patterns over length scales ranging from millimeters to micrometers to nanometers. The importance of highly sensitive surface analytical tools in the development of new chemically patterned surfaces is highlighted.

  3. Chemical datuments as scientific enablers.

    Science.gov (United States)

    Rzepa, Henry S

    2013-01-01

    This article is an attempt to construct a chemical datument as a means of presenting insights into chemical phenomena in a scientific journal. An exploration of the interactions present in a small fragment of duplex Z-DNA and the nature of the catalytic centre of a carbon-dioxide/alkene epoxide alternating co-polymerisation is presented in this datument, with examples of the use of three software tools, one based on Java, the other two using Javascript and HTML5 technologies. The implications for the evolution of scientific journals are discussed. PMID:23343381

  4. Chemical datuments as scientific enablers

    Directory of Open Access Journals (Sweden)

    Rzepa Henry S

    2013-01-01

    Full Text Available Abstract This article is an attempt to construct a chemical datument as a means of presenting insights into chemical phenomena in a scientific journal. An exploration of the interactions present in a small fragment of duplex Z-DNA and the nature of the catalytic centre of a carbon-dioxide/alkene epoxide alternating co-polymerisation is presented in this datument, with examples of the use of three software tools, one based on Java, the other two using Javascript and HTML5 technologies. The implications for the evolution of scientific journals are discussed.

  5. Synthesis of chemically modified DNA.

    Science.gov (United States)

    Shivalingam, Arun; Brown, Tom

    2016-06-15

    Naturally occurring DNA is encoded by the four nucleobases adenine, cytosine, guanine and thymine. Yet minor chemical modifications to these bases, such as methylation, can significantly alter DNA function, and more drastic changes, such as replacement with unnatural base pairs, could expand its function. In order to realize the full potential of DNA in therapeutic and synthetic biology applications, our ability to 'write' long modified DNA in a controlled manner must be improved. This review highlights methods currently used for the synthesis of moderately long chemically modified nucleic acids (up to 1000 bp), their limitations and areas for future expansion. PMID:27284032

  6. Chemical characterization of atmospheric particles

    International Nuclear Information System (INIS)

    In the characterisation of complex environmental materials such as atmospheric particulate matter, analytical specificity is required to account for the many dimensions of information present in the sample. These dimensions include size, morphology, elemental composition, inorganic and organic chemical speciation, all to be performed on either single particles or on the population (or bulk sample) basis. Various techniques were developed for such measurements, including a number of bulk analysis procedures, methodologies for microscopical analysis of individual particles, and a variety of procedures for organic/inorganic chemical speciation. (author)

  7. Identification numbers for chemical structures

    International Nuclear Information System (INIS)

    Several identification (ID) numbers for chemical structures (connectivity ID number, prime ID number, weighted ID number) are analyzed and tested until a counterexample (a pair of structures with the same ID number) is found. The analysis is carried out for acyclic structures with up to 20 atoms, trees with up to 20 points, benzenoid graphs and polyhexes with up to 10 hexagons, and all connected graphs with up to 6 points. Although all the (chemical) ID numbers studied are highly selective for many families of (molecular) graphs, none of them are unique; in all three cases the counterexamples are found. However, the greatest discriminative power is shown by the weighted ID number

  8. Chemical Modification of Food Proteins

    Institute of Scientific and Technical Information of China (English)

    Allaoua Achouri; Wang Zhang; Xu Shiying

    1999-01-01

    Acylation has been shown to be an effective tool for improving surface functional properties of plant proteins.Soy bean protein has been extensively modified through chemical and enzymatic treatments. Their effectiveness lies in their high nutritional value and low cost, which promote their use as ingredients for the formulation of food products.This paper reports a complete review of chemical modification of various proteins from plant and animal sources. The nutritive and toxicological aspects through in vitro and in vivo tests are also described.

  9. Effort problem of chemical pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Okrajni, J.; Ciesla, M.; Mutwil, K. [Silesian Technical University, Katowice (Poland)

    1998-12-31

    The problem of the technical state assessment of the chemical pipelines working under mechanical and thermal loading has been shown in the paper. The pipelines effort after the long time operating period has been analysed. Material geometrical and loading conditions of the crack initiation and crack growth process in the chosen object has been discussed. Areas of the maximal effort have been determined. The material structure charges after the long time operating period have been described. Mechanisms of the crack initiation and crack growth in the pipeline elements have been analysed and mutual relations between the chemical and mechanical influences have been shown. (orig.) 16 refs.

  10. Safety evaluation of chemical mixtures and combinations of chemical and non-chemical stressors.

    Science.gov (United States)

    Jonker, D; Freidig, A P; Groten, J P; de Hollander, A E M; Stierum, R H; Woutersen, R A; Feron, V J

    2004-01-01

    Recent developments in hazard identification and risk assessment of chemical mixtures are reviewed. Empirical, descriptive approaches to study and characterize the toxicity of mixtures have dominated during the past two decades, but an increasing number of mechanistic approaches have made their entry into mixture toxicology. A series of empirical studies with simple chemical mixtures in rats is described in some detail because of the important lessons from this work. The development of regulatory guidelines for the toxicological evaluation of chemical mixtures is discussed briefly. Current issues in mixture toxicology include the adverse health effects of ambient air pollution; the application of such modern, sophisticated methodologies as genomics, bioinformatics, and physiologically based pharmacokinetic modeling; and databases for mixture toxicity. Finally, the state of the art of our knowledge on the potential adverse health effects of combined exposures to chemicals and non-chemical stressors (noise, heat/cold, microorganisms, immobilization, restraint, or transportation), research initiatives in these fields, and the development of an indicator for the cumulative health impact of multiple environmental exposures are discussed. PMID:15329008

  11. Negative chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    This thesis describes some aspects of Negative Chemical Ionization (NCI) mass spectrometry. The reasons for the growing interest in NCI are: (i) to extend the basic knowledge of negative ions and their reactions in the gas phase; (ii) to investigate whether or not this knowledge of negative ions can be used successfully to elucidate the structure of molecules by mass spectrometry. (Auth.)

  12. The complex chemical Langevin equation

    International Nuclear Information System (INIS)

    The chemical Langevin equation (CLE) is a popular simulation method to probe the stochastic dynamics of chemical systems. The CLE’s main disadvantage is its break down in finite time due to the problem of evaluating square roots of negative quantities whenever the molecule numbers become sufficiently small. We show that this issue is not a numerical integration problem, rather in many systems it is intrinsic to all representations of the CLE. Various methods of correcting the CLE have been proposed which avoid its break down. We show that these methods introduce undesirable artefacts in the CLE’s predictions. In particular, for unimolecular systems, these correction methods lead to CLE predictions for the mean concentrations and variance of fluctuations which disagree with those of the chemical master equation. We show that, by extending the domain of the CLE to complex space, break down is eliminated, and the CLE’s accuracy for unimolecular systems is restored. Although the molecule numbers are generally complex, we show that the “complex CLE” predicts real-valued quantities for the mean concentrations, the moments of intrinsic noise, power spectra, and first passage times, hence admitting a physical interpretation. It is also shown to provide a more accurate approximation of the chemical master equation of simple biochemical circuits involving bimolecular reactions than the various corrected forms of the real-valued CLE, the linear-noise approximation and a commonly used two moment-closure approximation

  13. 2010 Chemical Working Group Status

    Science.gov (United States)

    Reid, Concha M.

    2010-01-01

    The Steering Group for the Interagency Advanced Power Group (IAPG) held their business meeting on November 30-December 1st in McLean, Virginia. Status reports were presented from each of the IAPG's Working Groups. These charts contain a brief summary of the IAPG Chemical Working Group's activities during 2010 and its plans for 2011.

  14. Chemical evolution of molecular clouds

    Science.gov (United States)

    Prasad, Sheo S.; Tarafdar, Sankar P.; Villere, Karen R.; Huntress, Wesley T., Jr.

    1987-01-01

    The principles behind the coupled chemical-dynamical evolution of molecular clouds are described. Particular attention is given to current problems involving the simplest species (i.e., C. CO, O2, and H2) in quiescent clouds. The results of a comparison made between the molecular abundances in the Orion ridge and the hot core (Blake, 1986) are presented.

  15. Topics on Galactic Chemical Evolution

    OpenAIRE

    Prantzos, Nikos

    2011-01-01

    I discuss three different topics in Galactic chemical evolution:the "puzzling" absence of any observational signature of secondary elements ; the building of the Galactic halo in the framework of hierarchical galaxy formation, as evidenced from its metallicity distribution ; and the potentially important role that radial migration may play in the evolution of galactic disks, according to recent studies.

  16. Chemical stratification of the mantle

    International Nuclear Information System (INIS)

    Differentation of the mantle results in a thick layer of basalt which cannot sink below about 670 km even after it converts to eclogite and garnetite. The mantle is therefore chemically stratified. The upper mantle stratification is possibly garnte peridotite overlying eclogite

  17. Chemical research at Rocky Flats

    International Nuclear Information System (INIS)

    An overview of the research projects in the Chemical Research group will be given. The work involves actinide waste and processing chemistry, separations chemistry, radiation studies, and calorimetry and thermodynamics. Details will be given of the actinide separations research, including work with macroreticular anion exchangers and bidentate organophosphorus extractants

  18. Simple Chemical Vapor Deposition Experiment

    Science.gov (United States)

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  19. Toxicological evaluation of chemical mixtures

    NARCIS (Netherlands)

    Feron, V.J.; Groten, J.P.

    2002-01-01

    This paper addresses major developments in the safety evaluation of chemical mixtures during the past 15 years, reviews today's state of the art of mixture toxicology, and discusses challenges ahead. Well-thought-out tailor-made mechanistic and empirical designs for studying the toxicity of mixtures

  20. Chemical reaction and separation method

    NARCIS (Netherlands)

    Jansen, J.C.; Kapteijn, F.; Strous, S.A.

    2005-01-01

    The invention is directed to process for performing a chemical reaction in a reaction mixture, which reaction produces water as by-product, wherein the reaction mixture is in contact with a hydroxy sodalite membrane, through which water produced during the reaction is removed from the reaction mixtu

  1. Apparent tunneling in chemical reactions

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Hansen, Flemming Yssing; Billing, G. D.

    2000-01-01

    A necessary condition for tunneling in a chemical reaction is that the probability of crossing a barrier is non-zero, when the energy of the reactants is below the potential energy of the barrier. Due to the non-classical nature (i.e, momentum uncertainty) of vibrational states this is, however...

  2. Apparent tunneling in chemical reactions

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Hansen, Flemming Yssing; Billing, G. D.

    A necessary condition for tunneling in a chemical reaction is that the probability of crossing a barrier is non-zero, when the energy of the reactants is below the potential energy of the barrier. Due to the non-classical nature (i.e, momentum uncertainty) of vibrational states this is, however...

  3. Biological and Chemical Information Technologies

    DEFF Research Database (Denmark)

    Amos, Martyn; Dittrich, Peter; McCaskill, John;

    2011-01-01

    Biological and chemical information technologies (bio/chem IT) have the potential to reshape the scientific and technological landscape. In this paper we briefly review the main challenges and opportunities in the field, before presenting several case studies based on ongoing FP7 research projects....

  4. Clad-coolant chemical interaction

    International Nuclear Information System (INIS)

    This paper provides an overview of the kinetics for zircaloy clad oxidation behaviour in steam and air during reactor accident conditions. The generation of chemical heat from metal/water reaction is considered. Low-temperature oxidation of zircaloy due to water-side corrosion is further described. (authors)

  5. Mechanisms of multiple chemical sensitivity.

    Science.gov (United States)

    Winder, Chris

    2002-03-10

    Sensitivity to chemicals is a toxicological concept, contained in the dose-response relationship. Sensitivity also includes the concept of hypersensitivity, although controversy surrounds the nature of effects from very low exposures. The term multiple chemical sensitivity has been used to describe individuals with a debilitating, multi-organ sensitivity following chemical exposures. Many aspects of this condition extend the nature of sensitivity to low levels of exposure to chemicals, and is a designation with medical, immunological, neuropsychological and toxicological perspectives. The basis of MCS is still to be identified, although a large number of hypersensitivity, immunological, psychological, neurological and toxicological mechanisms have been suggested, including: allergy; autosuggestion; cacosomia; conditioned response; immunological; impairment of biochemical pathways involved in energy production; impairment of neurochemical pathways; illness belief system; limbic kindling; olfactory threshold sensitivity; panic disorder; psychosomatic condition; malingering; neurogenic inflammation; overload of biotransformation pathways (also linked with free radical production); psychological or psychiatric illness; airway reactivity; sensitisation of the neurological system; time dependent sensitisation, toxicant induced loss of tolerance. Most of these theories tend to break down into concepts involving: (1) disruption in immunological/allergy processes; (2) alteration in nervous system function; (3) changes in biochemical or biotransformation capacity; (4) changes in psychological/neurobehavioural function. Research into the possible mechanisms of MCS is far from complete. However, a number of promising avenues of investigation indicate that the possibility of alteration of the sensitivity of nervous system cells (neurogenic inflammation, limbic kindling, cacosomia, neurogenic switching) are a possible mechanism for MCS. PMID:11869820

  6. Chemical Industry Waste water Treatment

    International Nuclear Information System (INIS)

    Treatment of chemical industrial wastewater from building and construction chemicals factory and plastic shoes manufacturing factory was investigated. The two factories discharge their wastewater into the public sewerage network. The results showed the wastewater discharged from the building and construction chemicals factory was highly contaminated with organic compounds. The average values of COD and BOD were 2912 and 150 mg O2/l. Phenol concentration up to 0.3 mg/l was detected. Chemical treatment using lime aided with ferric chloride proved to be effective and produced an effluent characteristics in compliance with Egyptian permissible limits. With respect to the other factory, industrial wastewater was mixed with domestic wastewater in order to lower the organic load. The COD, BOD values after mixing reached 5239 and 2615 mg O2/l. The average concentration of phenol was 0.5 mg/l. Biological treatment using activated sludge or rotating biological contactor (RBe) proved to be an effective treatment system in terms of producing an effluent characteristic within the permissible limits set by the law

  7. Chemical synthesis on SU-8

    DEFF Research Database (Denmark)

    Qvortrup, Katrine; Taveras, Kennedy; Thastrup, Ole;

    2011-01-01

    In this paper we describe a highly effective surface modification of SU-8 microparticles, the attachment of appropriate linkers for solid-supported synthesis, and the successful chemical modification of these particles via controlled multi-step organic synthesis leading to molecules attached in an...

  8. Chemical protection against ionizing radiation

    Science.gov (United States)

    Maisin, J. R.

    Some of the problems related to chemical protection against ionizing radiation are discussed with emphasis on : definition, classification, degree of protection, mechanisms of action and toxicity. Results on the biological response modifyers (BRMs) and on the combination of nontoxic (i.e. low) doses of sulphydryl radioprotectors and BRMs are presented.

  9. Chemical technology for appropriate development

    NARCIS (Netherlands)

    Van Brakel, J.

    1978-01-01

    'Chemical technology for appropriate development' is basicly a critical review of the literature. It gives a conceptual analysis of so called appropriate technology and the choice of production systems for less-development countries. The role of about 40 organizations active in this emerging field a

  10. Introduction to Galactic Chemical Evolution

    Science.gov (United States)

    Matteucci, Francesca

    2016-04-01

    In this lecture I will introduce the concept of galactic chemical evolution, namely the study of how and where the chemical elements formed and how they were distributed in the stars and gas in galaxies. The main ingredients to build models of galactic chemical evolution will be described. They include: initial conditions, star formation history, stellar nucleosynthesis and gas flows in and out of galaxies. Then some simple analytical models and their solutions will be discussed together with the main criticisms associated to them. The yield per stellar generation will be defined and the hypothesis of instantaneous recycling approximation will be critically discussed. Detailed numerical models of chemical evolution of galaxies of different morphological type, able to follow the time evolution of the abundances of single elements, will be discussed and their predictions will be compared to observational data. The comparisons will include stellar abundances as well as interstellar medium ones, measured in galaxies. I will show how, from these comparisons, one can derive important constraints on stellar nucleosynthesis and galaxy formation mechanisms. Most of the concepts described in this lecture can be found in the monograph by Matteucci (2012).

  11. Integrated opto-chemical sensors

    NARCIS (Netherlands)

    Lambeck, Paul V.

    1992-01-01

    Integrated opto-chemical sensors have promising prospects, for example by having the potential to be realized as very sensitive small monolithic smart multisensor systems with a digital signal output. Here the main accent will be laid on the optical principles underlying chemo-optical waveguiding se

  12. Physico-chemical wastewater treatment

    NARCIS (Netherlands)

    Mels, A.R.; Teerikangas, E.

    2002-01-01

    Wastewater reclamation strategies aimed at closing industrial water cycles and recovery of valuable components will in most cases require a combination of wastewater treatment unit operations. Biological unit operations are commonly applied as the core treatment. In addition, physico-chemical unit o

  13. Chemical protection against ionizing radiation

    International Nuclear Information System (INIS)

    Over 40 years have passed since the research of the Manhattan Project suggested the possibility of chemical protection against ionizing radiation. During that time, much has been learned about the nature of radiation-induced injury and the factors governing the expression of that injury. Thousands of compounds have been tested for radioprotective efficacy, and numerous theories have been proposed to account for these actions. The literature on chemical radioprotection is large. In this article, the authors consider several of the mechanisms by which chemicals may protect against radiation injury. They have chosen to accent this view of radioprotector research as opposed to that research geared toward developing specific molecules as protective agents because they feel that such an approach is more beneficial in stimulating research of general applicability. This paper describes the matrix of biological factors upon which an exogenous radioprotector is superimposed, and examines evidence for and against various mechanisms by which these agents may protect biological systems against ionizing radiation. It concludes with a brief outlook for research in chemical radioprotection

  14. Toxic chemical risk acceptance criteria

    International Nuclear Information System (INIS)

    This paper presents recommendations of a subcommittee of the Westinghouse M ampersand 0 Nuclear Facility Safety Committee concerning toxic chemical risk acceptance criteria. Two sets of criteria have been developed, one for use in the hazard classification of facilities, and the second for use in comparing risks in DOE non-reactor nuclear facility Safety Analysis Reports. The Emergency Response Planning Guideline (ERPG) values are intended to provide estimates of concentration ranges for specific chemicals above which exposure would be expected to lead to adverse heath effects of increasing severity for ERPG-1, -2, and -3s. The subcommittee recommends that criteria for hazard class or risk range be based on ERPGs for all chemicals. Probability-based Incremental Cancer Risk (ICR) criteria are recommended for additional analyses of risks from all known or suspected human carcinogens. Criteria are given for both on-site and off-site exposure. The subcommittee also recommends that the 5-minute peak concentration be compared with the relevant criterion with no adjustment for exposure time. Since ERPGs are available for only a limited number of chemicals, the subcommittee has developed a proposed hierarchy of concentration limit parameters for the different criteria

  15. The Chemical Composition of Honey

    Science.gov (United States)

    Ball, David W.

    2007-01-01

    Honey is a supersaturated sugar solution, created by bees, and used by human beings as a sweetener. However, honey is more than just a supersaturated sugar solution; it also contains acids, minerals, vitamins, and amino acids in varying quantities. In this article, we will briefly explore the chemical composition of honey. (Contains 2 figures and…

  16. ENGINEERING BULLETIN: CHEMICAL OXIDATION TREATMENT

    Science.gov (United States)

    Oxidation destroys hazardous contaminants by chemically converting them to nonhazardous or less toxic compounds that are ideally more stable, less mobile, and/or inert. However, under some conditions, other hazardous compounds may be formed. The oxidizing agents most commonly use...

  17. Chemical Principles Revisited: Archaeological Dating.

    Science.gov (United States)

    Rowe, M. W.

    1986-01-01

    Discusses methods used to date archaeological artifacts and other remains. They include: (1) nuclear dating techniques (radiocarbon dating, accelerator radiocarbon dating, thermoluminescence, and others); (2) chemical dating techniques (amino acid racemization, obsidian hydration dating, elemental content changes, and thermal analysis dating); and…

  18. Recommended Inorganic Chemicals for Calibration.

    Science.gov (United States)

    Moody, John R.; And Others

    1988-01-01

    All analytical techniques depend on the use of calibration chemicals to relate analyte concentration to instrumental parameters. Discusses the preparation of standard solutions and provides a critical evaluation of available materials. Lists elements by group and discusses the purity and uses of each. (MVL)

  19. Predicting Anatomical Therapeutic Chemical (ATC classification of drugs by integrating chemical-chemical interactions and similarities.

    Directory of Open Access Journals (Sweden)

    Lei Chen

    Full Text Available The Anatomical Therapeutic Chemical (ATC classification system, recommended by the World Health Organization, categories drugs into different classes according to their therapeutic and chemical characteristics. For a set of query compounds, how can we identify which ATC-class (or classes they belong to? It is an important and challenging problem because the information thus obtained would be quite useful for drug development and utilization. By hybridizing the informations of chemical-chemical interactions and chemical-chemical similarities, a novel method was developed for such purpose. It was observed by the jackknife test on a benchmark dataset of 3,883 drug compounds that the overall success rate achieved by the prediction method was about 73% in identifying the drugs among the following 14 main ATC-classes: (1 alimentary tract and metabolism; (2 blood and blood forming organs; (3 cardiovascular system; (4 dermatologicals; (5 genitourinary system and sex hormones; (6 systemic hormonal preparations, excluding sex hormones and insulins; (7 anti-infectives for systemic use; (8 antineoplastic and immunomodulating agents; (9 musculoskeletal system; (10 nervous system; (11 antiparasitic products, insecticides and repellents; (12 respiratory system; (13 sensory organs; (14 various. Such a success rate is substantially higher than 7% by the random guess. It has not escaped our notice that the current method can be straightforwardly extended to identify the drugs for their 2(nd-level, 3(rd-level, 4(th-level, and 5(th-level ATC-classifications once the statistically significant benchmark data are available for these lower levels.

  20. Radioactive sources in chemical laboratories

    International Nuclear Information System (INIS)

    Radioactive sources including all radioactive materials exceeding exemption levels have to be registered in national databases according to international standards based on the recommendations ICRP 60 and a proper licensing should take place as described for example in the 96/29/EURATOM. In spite of that, unregistered sources could be found, usually due to the fact that the owner is not aware of radiation characteristics of sources. The material inventories of chemical laboratories are typical and most frequent example where radioactive sources could be found. Five different types of sources could be identified. The most frequent type are chemicals, namely thorium and uranium compounds. They are used not due to their radioactivity but due to their chemical properties. As for all other sources a stringent control is necessary in order to assure their safe use. Around hundred of stored radioactive chemical items were found during inspections of such laboratories performed by the Slovenian Nuclear Safety Administration or qualified experts in a period December 2006 - July 2007. Users of such chemicals are usually not aware that thorium and uranium chemicals are radioactive and, as unsealed sources, they could be easily spilled out and produce contamination of persons, surfaces, equipment etc. The external exposure as well as the internal exposure including exposure due to inhalation could be present. No knowledge about special precautions is usually present in laboratories and leads to underestimating of a potential risk and unintentional exposure of the laboratory personnel, students etc. Due to the long decay times in decay series of Th -232, U-238 and U- 235 the materials are also radioactive today. Even more, in case of thorium chemicals the radioactivity increased substantially from the time of their production. The implementation of safety measures has been under way and includes a survey of the qualified experts, establishment of organizational structure in a

  1. A Short History of Three Chemical Shifts

    Science.gov (United States)

    Nagaoka, Shin-ichi

    2007-01-01

    A short history of chemical shifts in nuclear magnetic resonance (NMR), electron spectroscopy for chemical analysis (ESCA) and Mossbauer spectroscopy, which are useful for chemical studies, is described. The term chemical shift is shown to have originated in the mistaken assumption that nuclei of a given element would all undergo resonance at the…

  2. The chemical biology of sirtuins.

    Science.gov (United States)

    Chen, Bing; Zang, Wenwen; Wang, Juan; Huang, Yajun; He, Yanhua; Yan, Lingling; Liu, Jiajia; Zheng, Weiping

    2015-08-01

    The sirtuin family of enzymes are able to catalyze the N(ε)-acyl-lysine deacylation reaction on histone and non-histone protein substrates. Over the past years since the discovery of its founding member (i.e. the yeast silent information regulator 2 (sir2) protein) in 2000, the sirtuin-catalyzed deacylation reaction has been demonstrated to play an important regulatory role in multiple crucial cellular processes such as transcription, DNA damage repair, and metabolism. This reaction has also been regarded as a current therapeutic target for human diseases such as cancer, and metabolic and neurodegenerative diseases. The unique β-nicotinamide adenine dinucleotide (β-NAD(+) or NAD(+))-dependent nature of the sirtuin-catalyzed deacylation reaction has also engendered extensive mechanistic studies, resulting in a mechanistic view of the enzyme chemistry supported by several lines of experimental evidence. On the journey toward these knowledge advances, chemical biological means have constituted an important functional arsenal; technically, a variety of chemical probes and modulators (inhibitors and activators) have been developed and some of them have been employed toward an enhanced mechanistic and functional (pharmacological) understanding of the sirtuin-catalyzed deacylation reaction. On the other hand, an enhanced mechanistic understanding has also facilitated the development of a variety of chemical probes and modulators. This article will review the tremendous accomplishments achieved during the past few years in the field of sirtuin chemical biology. It is hoped that this would also help to set a stage for how outstanding mechanistic and functional questions for the sirtuin-catalyzed deacylation reaction could be addressed in the future from the chemical biology perspective. PMID:25955411

  3. Optical detection of chemical warfare agents and toxic industrial chemicals

    Science.gov (United States)

    Webber, Michael E.; Pushkarsky, Michael B.; Patel, C. Kumar N.

    2004-12-01

    We present an analytical model evaluating the suitability of optical absorption based spectroscopic techniques for detection of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) in ambient air. The sensor performance is modeled by simulating absorption spectra of a sample containing both the target and multitude of interfering species as well as an appropriate stochastic noise and determining the target concentrations from the simulated spectra via a least square fit (LSF) algorithm. The distribution of the LSF target concentrations determines the sensor sensitivity, probability of false positives (PFP) and probability of false negatives (PFN). The model was applied to CO2 laser based photoacosutic (L-PAS) CWA sensor and predicted single digit ppb sensitivity with very low PFP rates in the presence of significant amount of interferences. This approach will be useful for assessing sensor performance by developers and users alike; it also provides methodology for inter-comparison of different sensing technologies.

  4. Chemical morphogenesis: turing patterns in an experimental chemical system.

    Science.gov (United States)

    Dulos, E; Boissonade, J; Perraud, J J; Rudovics, B; De Kepper, P

    1996-11-01

    Patterns resulting from the sole interplay between reaction and diffusion are probably involved in certain stages of morphogenesis in biological systems, as initially proposed by Alan Turing. Self-organization phenomena of this type can only develop in nonlinear systems (i.e. involving positive and negative feedback loops) maintained far from equilibrium. We present Turing patterns experimentally observed in a chemical system. An oscillating chemical reaction, the CIMA reaction, is operated in an open spatial reactor designed in order to obtain a pure reaction-diffusion system. The two types of Turing patterns observed, hexagonal arrays of spots and parallel stripes, are characterized by an intrinsic wavelength. We identify the origin of the necessary diffusivity between activator and inhibitor. We also describe a pattern growth mechanism by spot splitting that recalls cell division. PMID:8953211

  5. Chemical Thermodynamics Vol. 12 - Chemical Thermodynamics of tin

    International Nuclear Information System (INIS)

    This is the 12th volume of a series of expert reviews of the chemical thermodynamics of key chemical elements in nuclear technology and waste management. This volume is devoted to the inorganic species and compounds of tin. The tables contained in Chapters III and IV list the currently selected thermodynamic values within the NEA TDB Project. The database system developed at the NEA Data Bank, see Section II.6, assures consistency among all the selected and auxiliary data sets. The recommended thermodynamic data are the result of a critical assessment of published information. The values in the auxiliary data set, see Tables IV-1 and IV-2, have been adopted from CODATA key values or have been critically reviewed in this or earlier volumes of the series

  6. Prediction of cancer drugs by chemical-chemical interactions.

    Directory of Open Access Journals (Sweden)

    Jing Lu

    Full Text Available Cancer, which is a leading cause of death worldwide, places a big burden on health-care system. In this study, an order-prediction model was built to predict a series of cancer drug indications based on chemical-chemical interactions. According to the confidence scores of their interactions, the order from the most likely cancer to the least one was obtained for each query drug. The 1(st order prediction accuracy of the training dataset was 55.93%, evaluated by Jackknife test, while it was 55.56% and 59.09% on a validation test dataset and an independent test dataset, respectively. The proposed method outperformed a popular method based on molecular descriptors. Moreover, it was verified that some drugs were effective to the 'wrong' predicted indications, indicating that some 'wrong' drug indications were actually correct indications. Encouraged by the promising results, the method may become a useful tool to the prediction of drugs indications.

  7. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    1969-01-01

    High Resolution NMR: Theory and Chemical Applications focuses on the applications of nuclear magnetic resonance (NMR), as well as chemical shifts, lattices, and couplings. The book first offers information on the theory of NMR, including nuclear spin and magnetic moment, spin lattice relaxation, line widths, saturation, quantum mechanical description of NMR, and ringing. The text then ponders on instrumentation and techniques and chemical shifts. Discussions focus on the origin of chemical shifts, reference compounds, empirical correlations of chemical shifts, modulation and phase detection,

  8. Chemical Reactivity as Described by Quantum Chemical Methods

    OpenAIRE

    De Proft, F.; Geerlings, P.

    2002-01-01

    Abstract: Density Functional Theory is situated within the evolution of Quantum Chemistry as a facilitator of computations and a provider of new, chemical insights. The importance of the latter branch of DFT, conceptual DFT is highlighted following Parr's dictum "to calculate a molecule is not to understand it". An overview is given of the most important reactivity descriptors and the principles they are couched in. Examples are given on the evolution of the structure-property-wave function t...

  9. Plant protective chemicals in forestry

    International Nuclear Information System (INIS)

    The aim of the present study is to examine critically the use of pesticides in forestry and the resulting problems. Further, the study points out possibilities for dispensing with chemical treatments altogether. This work is intended to assist those deciding upon suitable forest protection procedures. There are also comments on the particular dangers arising from the use of pesticides (R-Saetze) and safety advice as regards their proper application. The first part of the present study contains both a discussion of the humanotoxicological and ecological consequences of pesticide applications in forestry as well as the legal basis for the sale and use of pesticides in Austria. The following parts (herbicides, insecticides, rodenticides, game deterrents, fungicides) treat the use of pesticides according to their respective area of application. Discussed here are chemical properties, toxicity, and the environmental compatibility of the pesticides in question, including demonstrations of environmentally sound ways to avoid or restrict the use of pesticides. (authors)

  10. Heuristics for chemical compound matching.

    Science.gov (United States)

    Hattori, Masahiro; Okuno, Yasushi; Goto, Susumu; Kanehisa, Minoru

    2003-01-01

    We have developed an efficient algorithm for comparing two chemical compounds, where the chemical structure is treated as a 2D graph consisting of atoms as vertices and covalent bonds as edges. Based on the concept of functional groups in chemistry, 68 atom types (vertex types) are defined for carbon, nitrogen, oxygen, and other atomic species with different environments, which has enabled detection of biochemically meaningful features. Maximal common subgraphs of two graphs can be found by searching for maximal cliques in the association graph, and we have introduced heuristics to accelerate the clique finding. Our heuristic procedure is controlled by some adjustable parameters. Here we applied our procedure to the latest KEGG/LIGAND database with different sets of parameters, and demonstrated the correlation of parameters in our algorithm with the distribution of similarity scores and/or the execution time. Finally, we showed the effectiveness of our heuristics for compound pairs along metabolic pathways. PMID:15706529

  11. Chemical Lineages of Ligularia fischeri.

    Science.gov (United States)

    Kuroda, Chiaki; Shibayama, Chiemi; Inoue, Kyosuke; Okamoto, Yasuko; Tori, Motoo; Saito, Yoshinori; Hanai, Ryo; Gong, Xun

    2016-02-01

    Six Ligularia fischeri samples, two from Sichuan (samples 1 and 2) and four from Chongqing (samples 3-6), were examined for root chemicals and the DNA sequence of the internal transcribed spacers of the ribosomal RNA gene. Samples 2 and 3 contained benzofurans. The isolation of benzofurans shows that the chemical diversity in L. fischeri is higher than previously reported. Samples 1, 4, 5, and 6 contained eremophilanes. However, the compounds were different between sample 1 and samples 4-6, indicating variation within eremophilane producers. DNA data indicated that introgression could be a mechanism of benzofuran production in sample 2 and that sample 1 and samples 4-6 were genetically separate. PMID:27032186

  12. [Chemical constituents of Desmodium sambuense].

    Science.gov (United States)

    Li, Chuankuan; Zhang, Qianjun; Huang, Zhongbi; Chen, Qing; Yao, Rongjun

    2010-09-01

    The chemical constituents of Desmodium sambuense were studied. Chromatographic techniques were applied to isolate and purify the constituents, and the structures were identified on the basis of physico-chemical and spectroscopeic methods. Thirteen compounds were isolated from the 75% ethanol extract of Desmodium sambuens and elucidated as beta-amyrin(1), betulic acid(2), daucosterol(3), triacontanoic acid(4), lup-20(29)-en-3-one(5), tetracosanoic-2,3-dihydroxypropylester(6), stigmast-5-ene-3beta, 7alpha-ol (7),methyl phaeophorbidea(8), o-hydroxy benzoic acid(9),beta-sitosterol(10),d-catechin(11), luteolin (12), epigallocatechin (13). All of the compounds were isolated from this plant for the first time. PMID:21141491

  13. Chemical constituents from Abutilon indicum.

    Science.gov (United States)

    Kuo, Ping-Chung; Yang, Mei-Lin; Wu, Pei-Lin; Shih, Hui-Nung; Thang, Tran Dinh; Dung, Nguyen Xuan; Wu, Tian-Shung

    2008-01-01

    The investigation on the chemical constituents of the whole plant of Abutilon indicum has resulted in the isolation of two new compounds, abutilin A (1) and (R)-N-(1'-methoxycarbonyl-2'-phenylethyl)-4-hydroxybenzamide (2), as well as 28 known compounds. The structures of the two new compounds were established on the basis of the spectroscopic analysis, and the known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literature. PMID:18636384

  14. Chemically powered micro- and nanomotors

    OpenAIRE

    Sanchez, Samuel; Soler Turu, Lluís; Katuri, Jaideep

    2015-01-01

    Chemically powered micro- and nanomotors are small devices that are self-propelled by catalytic reactions in fluids. Taking inspiration from biomotors, scientists are aiming to find the best architecture for self-propulsion, understand the mechanisms of motion, and develop accurate control over the motion. Remotely guided nanomotors can transport cargo to desired targets, drill into biomaterials, sense their environment, mix or pump fluids, and clean polluted water. This Review summarizes the...

  15. Chemical modeling of waste sludges

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.F.; Beahm, E.C.

    1996-10-01

    The processing of waste from underground storage tanks at the Oak Ridge National Laboratory (ORNL) and other facilities will require an understanding of the chemical interactions of the waste with process chemicals. Two aspects of sludge treatment should be well delineated and predictable: (1) the distribution of chemical species between aqueous solutions and solids, and (2) potential problems due to chemical interactions that could result in process difficulties or safety concerns. It is likely that the treatment of waste tank sludge will begin with washing, followed by basic or acidic leaching. The dissolved materials will be in a solution that has a high ionic strength where activity coefficients are far from unity. Activity coefficients are needed in order to calculate solubilities. Several techniques are available for calculating these values, and each technique has its advantages and disadvantages. The techniques adopted and described here is the Pitzer method. Like any of the methods, prudent use of this approach requires that it be applied within concentration ranges where the experimental data were fit, and its use in large systems should be preceded by evaluating subsystems. While much attention must be given to the development of activity coefficients, other factors such as coprecipitation of species and Ostwald ripening must also be considered when one aims to interpret results of sludge tests or to predict results of treatment strategies. An understanding of sludge treatment processes begins with the sludge tests themselves and proceeds to a general interpretation with the aid of modeling. One could stop with only data from the sludge tests, in which case the table of data would become an implicit model. However, this would be a perilous approach in situations where processing difficulties could be costly or result in concerns for the environment or health and safety.

  16. Chemical Warfare: Drugs in Sports

    OpenAIRE

    Percy, E. C.

    1980-01-01

    A number of substances have been used by athletes in an attempt to improve performance in sports. The use of these substances, which are referred to as ergogenic aids, has become widespread; some pose serious health hazards. Ergogenic aids are divided into five broad classifications: physiological, physical, psychological, nutritional and chemical. It is possible, although conclusive proof is lacking, that some substances may give an athlete who takes them an advantage over one who does not. ...

  17. Galaxy formation and chemical evolution

    OpenAIRE

    2014-01-01

    The manner the galaxy accretes matter along with the star formation rates at different epochs, influence the evolution of the stable isotopic inventories of the galaxy. A detailed analysis is presented here to study the dependence of the galactic chemical evolution on the accretion scenario of the galaxy along with the star formation rate during the early accretionary phase of the galactic thick disk and thin disk. Our results indicate that a rapid early accretion of the galaxy during the for...

  18. The chemical neuroanatomy of breathing

    OpenAIRE

    Alheid, George F.; McCrimmon, Donald R.

    2008-01-01

    The chemical neuroanatomy of breathing must ultimately encompass all the various neuronal elements physiologically identified in brainstem respiratory circuits and their apparent aggregation into “compartments” within the medulla and pons. These functionally defined respiratory compartments in the brainstem provide the major source of input to cranial motoneurons controlling the airways, and to spinal motoneurons activating inspiratory and expiratory pump muscles. This review provides an over...

  19. Chemical Specification of Autonomic Systems

    OpenAIRE

    Banâtre, Jean-Pierre; Fradet, Pascal; Radenac, Yann

    2004-01-01

    Autonomic computing provides a vision of information systems allowing self-management of many predefined properties. Such systems take care of their own behavior and of their interactions with other components without any external intervention. One of the major challenges concerns the expression of properties and constraints of autonomic systems. We believe that the {\\em chemical programming paradigm} (represented here by the Gamma formalism) is well-suited to the specification of autonomic s...

  20. Chemical equilibrium modeling of detonation

    Energy Technology Data Exchange (ETDEWEB)

    Fried, Laurence E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bastea, Sorin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2010-05-19

    Energetic materials are unique for having a strong exothermic reactivity, which has made them desirable for both military and commercial applications. Energetic materials are commonly divided into high explosives, propellants, and pyrotechnics. We will focus on high explosive (HE) materials here, although there is a great deal of commonality between the classes of energetic materials. Furthermore the history of HE materials is long, their condensed-phase chemical properties are poorly understood.

  1. Chemical Characterization of Asturian Cider

    OpenAIRE

    Picinelli, A.M. (Anna); Suárez, Belén; Moreno, Javier; Rodríguez, Roberto; Caso-García, L.M. (Lourdes); Mangas, J.J. (Juan)

    2011-01-01

    Ninety-four samples of Asturian natural cider were analyzed for titratable and volatile acidities, pH, alcoholic, total polyphenol, and acidic polysaccharide contents, nonvolatile acids, polyalcohols, residual sugars, and major volatile compounds. A partial least-squares regression analysis (PLR-1) was performed to correlate the chemical composition and the origin of the raw material, the cider samples being grouped into two categories: an “odd” class, cider made from foreign appl...

  2. Helium in Chemically Peculiar Stars

    OpenAIRE

    Leone, F.

    1998-01-01

    For the purpose of deriving the helium abundances in chemically peculiar stars, the importance of assuming a correct helium abundance has been investigated for determining the effective temperature and gravity of main sequence B-type stars, making full use of the present capability of reproducing their helium lines. Even if the flux distribution of main sequence B-type stars appears to depend only on the effective temperature for any helium abundance, the effective temperature, gravity and he...

  3. Chemical logging of geothermal wells

    Science.gov (United States)

    Allen, C.A.; McAtee, R.E.

    The presence of geothermal aquifers can be detected while drilling in geothermal formations by maintaining a chemical log of the ratio of the concentrations of calcium to carbonate and bicarbonate ions in the return drilling fluid. A continuous increase in the ratio of the concentrations of calcium to carbonate and bicarbonate ions is indicative of the existence of a warm or hot geothermal aquifer at some increased depth.

  4. Chemical Classification of Space Debris

    Institute of Scientific and Technical Information of China (English)

    LI Chunlai; ZUO Wei; LIU Jianjun; OUYANG Ziyuan

    2004-01-01

    Space debris, here referring to all non-operating orbital objects, has steadily increased in number so that it has become a potential barrier to the exploration of space. The ever-increasing number of space debris pieces in space has created an increasingly threatening hazard to all on-the-orbit spacecraft, and all future space exploration activities have to be designed and operated with respect to the increasing threat posed by space debris. Generally, space debris is classified as large, medium and small debris pieces based on their sizes. The large debris piece is easily catalogued, but medium to small debris pieces are very difficult to track and also quite different in damage mechanisms from the large ones. In this paper, a scheme of chemical classification of space debris is developed. In our scheme, the first-order classification is employed to divide space debris into two groups: natural micrometeoroids and artificial space debris.The second-order classification is based on their chemical patterns and compositions. The natural micrometeoroids are further divided into three types, namely maric, metal and phyllosilicate micrometeorites, while the artificial space debris is divided into seven types, which are polymers, non-metal debris, metals and their alloys, oxides, sulphides and their analogs, halides and carbides. Of the latter seven types, some can also be further divided into several sub-types. Chemical classification of space debris is very useful for the study of the chemical damage mechanism of small debris pieces, and also is of great significance in constraining the origin and source of space debris and assessing their impact on spacecraft and human space activities.

  5. Waste management and chemical inventories

    Energy Technology Data Exchange (ETDEWEB)

    Gleckler, B.P.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the classification and handling of waste at the Hanford Site. Waste produced at the Hanford Site is classified as either radioactive, nonradioactive, or mixed waste. Radioactive wastes are further categorized as transuranic, high-level, and low-level. Mixed waste may contain both radioactive and hazardous nonradioactive substances. This section describes waste management practices and chemical inventories at the site.

  6. A New Paradigm for Chemical Engineering?

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    system boundary under investigation? A fundamental rethinking of how to identify the needed chemicals based products and how to design, build and operate the corresponding production units, is necessary. Indeed, the chemical industry today is changed from the chemical industry of forty years ago. Clear...... evidence of this change comes from the jobs taken by graduating chemical engineering professionals in North America, Europe, and some of the Asian countries. In terms of where the graduating chemical engineers are going to work, a clear shift from the commodity chemical industry to the product oriented...... businesses has been observed. There is an increasing trend within the chemical industry to focus on products and the sustainable processes that can make them. Do these changes point to a paradigm shift in chemical engineering as a discipline? Historically, two previous paradigm shifts in chemical engineering...

  7. Chemical sensors for nuclear industry

    International Nuclear Information System (INIS)

    Development of chemical sensors for detection of gases at trace levels for applications in nuclear industry will be highlighted. The sensors have to be highly sensitive, reliable and rugged with long term stability to operate in harsh industrial environment. Semiconductor and solid electrolyte based electrochemical sensors satisfy the requirements. Physico-chemical aspects underlying the development of H2 sensors in sodium and in cover gas circuit of the Fast breeder reactors for its smooth functioning, NH3 and H2S sensors for use in Heavy water production industries and NOx sensors for spent fuel reprocessing plants will be presented. Development of oxygen sensors to monitor the oxygen level in the reactor containments and sodium sensors for detection of sodium leakages will also be discussed. The talk will focus the general aspects of identification of the sensing material for the respective analyte species, development of suitable chemical route for preparing them as fine powders, the need for configuring them in thick film or thin film geometries and their performance. Pulsed laser deposition method, an elegant technique to prepare the high quality thin films of multicomponent oxides is demonstrated for preparation of nanostructured thin films of complex oxides and its use in tailoring the morphology of the complex sensing material in the desired form by optimizing the in-situ growth conditions. (author)

  8. Physical and chemical coal cleaning

    Science.gov (United States)

    Wheelock, T. D.; Markuszewski, R.

    1981-02-01

    Coal is cleaned industrially by freeing the occluded mineral impurities and physically separating the coal and refuse particles on the basis of differences in density, settling characteristics, or surface properties. While physical methods are very effective and low in cost when applied to the separation of coarse particles, they are much less effective when applied to the separation of fine particles. Also they can not be used to remove impurities which are bound chemically to the coal. These deficiencies may be overcome in the future by chemical cleaning. Most of the chemical cleaning methods under development are designed primarily to remove sulfur from coal, but several methods also remove various trace elements and ash-forming minerals. Generally these methods will remove most of the sulfur associated with inorganic minerals, but only a few of the methods seem to remove organically bound sulfur. A number of the methods employ oxidizing agents as air, oxygen, chlorine, nitrogen dioxide, or a ferric salt to oxidize the sulfur compounds to soluble sulfates which are then extracted with water. The sulfur in coal may also be solubilized by treatment with caustic. Also sulfur can be removed by reaction with hydrogen at high temperature. Furthermore, it is possible to transform the sulfur bearing minerals in coal to materials which are easily removed by magnetic separation.

  9. Plasmonic gas and chemical sensing

    Science.gov (United States)

    Tittl, Andreas; Giessen, Harald; Liu, Na

    2014-06-01

    Sensitive and robust detection of gases and chemical reactions constitutes a cornerstone of scientific research and key industrial applications. In an effort to reach progressively smaller reagent concentrations and sensing volumes, optical sensor technology has experienced a paradigm shift from extended thin-film systems towards engineered nanoscale devices. In this size regime, plasmonic particles and nanostructures provide an ideal toolkit for the realization of novel sensing concepts. This is due to their unique ability to simultaneously focus light into subwavelength hotspots of the electromagnetic field and to transmit minute changes of the local environment back into the farfield as a modulation of their optical response. Since the basic building blocks of a plasmonic system are commonly noble metal nanoparticles or nanostructures, plasmonics can easily be integrated with a plethora of chemically or catalytically active materials and compounds to investigate processes ranging from hydrogen absorption in palladium to the detection of trinitrotoluene (TNT). In this review, we will discuss a multitude of plasmonic sensing strategies, spanning the technological scale from simple plasmonic particles embedded in extended thin films to highly engineered complex plasmonic nanostructures. Due to their flexibility and excellent sensing performance, plasmonic structures may open an exciting pathway towards the detection of chemical and catalytic events down to the single molecule level.

  10. Dow's chemical exposure index guide

    International Nuclear Information System (INIS)

    A number of events in the 1970's and 1980's impacted the course of process safety. Incidents such as Flixborough, Seveso, Three-Mile Island, and Bhopal are well known throughout industry and are recognized as examples of major disasters. Even though events leading up to these disasters were completely different they had one common element between them: a substance was released from a manufacturing unit, became airborne and presented a hazard of such magnitude as to place the safety of both employees and the surrounding public in jeopardy. As a result, industry became increasingly concerned regarding potential loss, in human and economic terms, as plants and equipment grew in size. The Flixborough incident raised the level of concern for process safety, particularly in terms of the hazards presented by fire and explosion. Seveso and Three-Mile Island emphasized the need to consider far-field exposure. The Bhopal incident created an urgent need to recognize and understand the expected downwind impact of potential releases of acutely toxic substances to the air. In order to meet this need, the Dow Chemical Company, a recognized leader in the area of safety and loss prevention, presented a Chemical Exposure Index in 1986. AIChE has recently published an updated version entitled Dow's Chemical Exposure Index Guide. 7 refs., 5 figs

  11. Chemical Disarmament: Current Problems in Implementing the Chemical Weapons Convention

    Directory of Open Access Journals (Sweden)

    Matoušek, J.

    2006-03-01

    Full Text Available The Chemical Weapons Convention (CWC is briefly characterised by stressing its main pillars, such as verified destruction ofCWstockpiles and destruction/conversion ofCWproduction facilities (CWPFs, verified non-production of CW by the chemical industries, assistance and protection, and international cooperation. The CWC´s leading principle in defining theCW(protecting it generally against scientific and technological development, i. e. so called General Purpose Criterion is thoroughly elucidated showing its relation to the CWC´s sophisticated verification system. Status of implementation (as of August 2005 shows main data obligatory declared by the States Parties (SP, among them 6 possessors of CW stockpiles (Russia, USA, India, South Korea, Albania and Libya. From the declared 71 373 agent-tons, 12 889 have been destroyed, from the declared 8 679 M items of munitions (containers, 2 420 have been destroyed, which means that the anticipated 10 years deadline for CW destruction (after entry into force – EIF will be not managed. For Russia and USA the allowed extension by another 5 years has been already agreed. From the 64 CWPFs (operational after 1946, declared by 12 SPs, 53 have been certified as destroyed/converted. The Organisation for the Prohibition of Chemical Weapons (OPCW is briefly presented and main results of the First Review Conference (2003 analysed on the base of the adopted principal documents. Future problems of implementing the CWC are connected in the first line with its universality, because among 16 non-SPs, several countries (located mainly in the Near East and on the Korean peninsula are presumed to be CW-possessors. Special emphasis is laid on both, threats and benefits of the scientific and technological development for current implementing the CWC as well as of its implementation in future after all CW stockpiles have been destroyed.

  12. Thermodynamic chemical energy transfer mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium chemical reactions

    International Nuclear Information System (INIS)

    Chemical energy transfer mechanisms at finite temperature are explored by a chemical energy transfer theory which is capable of investigating various chemical mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium. Gibbs energy fluxes are obtained as a function of chemical potential, time, and displacement. Diffusion, convection, internal convection, and internal equilibrium chemical energy fluxes are demonstrated. The theory reveals that there are chemical energy flux gaps and broken discrete symmetries at the activation chemical potential, time, and displacement. The statistical, thermodynamic theory is the unification of diffusion and internal convection chemical reactions which reduces to the non-equilibrium generalization beyond the quasi-equilibrium theories of migration and diffusion processes. The relationship between kinetic theories of chemical and electrochemical reactions is also explored. The theory is applied to explore non-equilibrium chemical reactions as an illustration. Three variable separation constants indicate particle number constants and play key roles in describing the distinct chemical reaction mechanisms. The kinetics of chemical energy transfer accounts for the four control mechanisms of chemical reactions such as activation, concentration, transition, and film chemical reactions. - Highlights: • Chemical energy transfer theory is proposed for non-, quasi-, and equilibrium. • Gibbs energy fluxes are expressed by chemical potential, time, and displacement. • Relationship between chemical and electrochemical reactions is discussed. • Theory is applied to explore nonequilibrium energy transfer in chemical reactions. • Kinetics of non-equilibrium chemical reactions shows the four control mechanisms

  13. 77 FR 74685 - Chemical Facility Anti-Terrorism Standards (CFATS) Chemical-Terrorism Vulnerability Information...

    Science.gov (United States)

    2012-12-17

    ... (IFR), implementing this statutory mandate at 72 FR 17688. Section 550 of the Homeland Security... SECURITY Chemical Facility Anti-Terrorism Standards (CFATS) Chemical- Terrorism Vulnerability Information... financial information, Chemical-terrorism Vulnerability Information (CVI), Sensitive Security...

  14. Thermodynamically predicted oscillations in closed chemical systems

    CERN Document Server

    Zilbergleyt, B

    2010-01-01

    All known up to now models of chemical oscillations are based exclusively on kinetic considerations. The chemical gross-process equation is split usually by elementary steps, each step is supplied by an arrow and a differential equation, joint solution to such a construction under certain, often ad hoc chosen conditions and with ad hoc numerical coefficients leads to chemical oscillations. Kinetic perception of chemical oscillations reigns without exclusions. However, as it was recently shown by the author for the laser and for the electrochemical systems, chemical oscillations follow also from solutions to the basic expressions of discrete thermodynamics of chemical equilibria. Graphically those solutions are various fork bifurcation diagrams, and, in certain types of chemical systems, oscillations are well pronounced in the bistable bifurcation areas. In this work we describe a general thermodynamic approach to chemical oscillations as opposite to kinetic models, and depict some of their new features like s...

  15. Mixture toxicity of PBT-like chemicals

    DEFF Research Database (Denmark)

    Syberg, Kristian; Dai, Lina; Ramskov, Tina;

    Even though most chemicals regulation is still conducted on a chemical by chemical basis, mixture toxicity is achieving increasing attention. The scientific understanding has increased substantially in the last decades, and a general consensus now seems to have been acieved that concentration...... addition is a suitable model for default estimations of mixture effects. One of the major challenges is therefore how to select specific chemicals for actual mixture toxicity assessments. Persistant chemicals are likely to be present in the environment for an extended period of time, thus increasing the...... likelihood of them being present in environmentally found mixtures. Persistant, bioaccumulative and toxic (PBT) chemicals are therefore a highly relevant group of chemicals to consider for mixture toxicity regulation. The present study evaluates to what extent a number of PBT-like chemicals posess concern...

  16. Chemical cleaning specification: few tube test model

    International Nuclear Information System (INIS)

    The specification is for the waterside chemical cleaning of the 2 1/4 Cr - 1 Mo steel steam generator tubes. It describes the reagents and conditions for post-chemical cleaning passivation of the evaporator tubes

  17. Chemical reagent and process for refuse disposal

    International Nuclear Information System (INIS)

    A process for treating refuse by mixing them with a reactive chemical and a puzzolana-type material. Said chemical includes a retarding agent which modifies the viscosity and an accelerating agent. (author)

  18. Laser-induced chemical reactions

    International Nuclear Information System (INIS)

    A classical model for the interaction of laser radiation with a molecular system is derived. This model is used to study the enhancement of a chemical reaction via a collision induced absorption. It was found that an infrared laser will in general enhance the rate of a chemical reaction, even if the reactants are infrared inactive. Results for an illustrative analytically solvable model are presented, as well as results from classical trajectory studies on a number of systems. The collision induced absorption spectrum in these systems can be written as the Fourier transform of a particular dipole correlation function. This is used to obtain the collision induced absorption spectrum for a state-selected, mono-energetic reactive collision system. Examples treated are a one-dimensional barrier problem, reactive and nonreactive collisions of H + H2, and a modified H + H2 potential energy surface which leads to a collision intermediate. An extension of the classical model to treat laser-induced electronically nonadiabatic collision processes is constructed. The model treats all degrees of freedom, molecular, electronic and radiation, in a dynamically consistent framework within classical mechanics. Application is made to several systems. Several interesting phenomena are discovered including a Franck-Condon-like effect causing maxima in the reaction probability at energies much below the classical threshold, laser de-enhancement of chemical reactions and an isotope effect. In order to assess the validity of the classical model for electronically nonadiabatic process (without a laser field), a model problem involving energy transfer in a collinear atom-diatom system is studied, and the results compared to the available quantum mechanical calculation. The calculations are in qualitative agreement

  19. Nonlinear Chemical Dynamics and Synchronization

    Science.gov (United States)

    Li, Ning

    Alan Turing's work on morphogenesis, more than half a century ago, continues to motivate and inspire theoretical and experimental biologists even today. That said, there are very few experimental systems for which Turing's theory is applicable. In this thesis we present an experimental reaction-diffusion system ideally suited for testing Turing's ideas in synthetic "cells" consisting of microfluidically produced surfactant-stabilized emulsions in which droplets containing the Belousov-Zhabotinsky (BZ) oscillatory chemical reactants are dispersed in oil. The BZ reaction has become the prototype of nonlinear dynamics in chemistry and a preferred system for exploring the behavior of coupled nonlinear oscillators. Our system consists of a surfactant stabilized monodisperse emulsion of drops of aqueous BZ solution dispersed in a continuous phase of oil. In contrast to biology, here the chemistry is understood, rate constants are measured and interdrop coupling is purely diffusive. We explore a large set of parameters through control of rate constants, drop size, spacing, and spatial arrangement of the drops in lines and rings in one-dimension (1D) and hexagonal arrays in two-dimensions (2D). The Turing model is regarded as a metaphor for morphogenesis in biology but not for prediction. Here, we develop a quantitative and falsifiable reaction-diffusion model that we experimentally test with synthetic cells. We quantitatively establish the extent to which the Turing model in 1D describes both stationary pattern formation and temporal synchronization of chemical oscillators via reaction-diffusion and in 2D demonstrate that chemical morphogenesis drives physical differentiation in synthetic cells.

  20. Personal Simulator of Chemical Process

    Institute of Scientific and Technical Information of China (English)

    吴重光

    2002-01-01

    The Personal Simulator of chemical process (PS) means that fully simulationsoftware can be run on one personal computer. This paper describes the kinds of PSprograms, its features, the graphic functions and three examples. PS programs are allbased on one object-oriented and real-time simulation software environment. Authordevelops this simulation software environment. An example of the batch reaction kineticsmodel is also described. Up to now a lot of students in technical schools and universitieshave trained on PS. The training results are very successful.

  1. Chemical compatibility of cartridge materials

    Science.gov (United States)

    Ambrose, Bryan; Wilcox, R. C.; Zee, R. H.

    1992-01-01

    The objectives were to determine the chemical compatibility of titanium-zirconium-molybdenum (TZM) with GaAs and CdZnTe, and Inconel with HgCdTe and HgZnTe. At the present time, no other studies regarding the compatibility of these crystal components and their respective cartridge materials have been performed. This study was to identify any possible problems between these materials to insure proper containment of possibly hazardous fumes during crystal growth experiments. In this study, the reaction zone between the materials was studied and the amount of degradation to the system was measured. Detailed results are presented.

  2. [Chemical constituents from Spatholobus sinensis].

    Science.gov (United States)

    Yin, Ting; Liu, Hua; Wang, Bin; Tu, Guang-Zhong; Liang, Hong; Zhao, Yu-Ying

    2008-01-01

    Spatholobus sinensis is a plant of the Spatholobus genus (Leguminosae family). Its caulis are used as "ji-xue-teng" regionally. However, to our knowledge, no phytochemical investigation on S. sinensis has been reported to date. In this study, eight compounds were isolated from the ethanol extract of the caulis of S. sinensis, by solvents extraction and column chromatography methods. By analysis of their physic-chemical constants and spectral data, the structures of 8 compounds were identified as spatholosineside A (1), 2',4',5,7-tetrahydroxyisoflavone (2), isoliquiritigenin (3), lupinalbin A (4), coumestrol (5), naringenin (6), protocatechuic acid (7), leonuriside A (8). Compound 1 is a new compound. PMID:18357735

  3. Comets - Chemistry and chemical evolution

    Science.gov (United States)

    Donn, B.

    1982-01-01

    Research on the chemical composition and conditions in comets and their possible role in the origin of life on earth is surveyed. The inorganic and organic compounds and ions indicated in the ultraviolet and visible spectra of comets are noted, and evidence for the existence of at least a small proportion of complex organic molecules in comets is presented. It is then pointed out that while cometary material could have reached the earth and provided volatile elements from which biochemical compounds could have formed, it is unlikely that a cometary nucleus could have withstood the temperatures and pressures necessary to sustain an environment in which life could have originated.

  4. Chemical stratification of the mantle

    Science.gov (United States)

    Anderson, D. L.

    1979-01-01

    A possible scenario for the chemical stratification of the earth's mantle is presented. Differentiation of the mantle by either the production of basaltic magmas or partial melting by the upper mantle is proposed to lead to a thick basalt layer, the lower part of which is converted to eclogite as the earth cools. Density estimates indicate that the eclogite formed would not be able to sink to below 670 km. The eclogite layer is thus demonstrated to be trapped as a result of whole-mantle convection and possible irreversible differentiation of the mantle into eclogite and overlying residual peridotite layers.

  5. Radiation-chemical antielectrostatic finishing

    International Nuclear Information System (INIS)

    Antielectrostatic finishing of textile fabrics of poly(ethylene terephthalate) was performed by radiation-chemical coating of poly(ethyleneglycol acrylate)s. The achieved modification effect was investigated with regard to its permanence mainly by recording the course of surface resistivity, and as a function of the composition of the modifier (monoacrylate/diacrylate ratio, molar mass), impregnation time and temperature, residual moisture, mass increase, energy dose, and dose rate. Detailed analytical and microscopic investigations evidenced important findings concerning the optimal technology of modification. The results permitted to suggest favorable modification parameters for satisfactory permanence of the effect. (author)

  6. Speciality chemicals from synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.J.; Knifton, J.F. (Shell Development Company, Houston, TX (USA))

    1992-04-01

    Texaco has undertaken research to investigate the use of carbon monoxide and hydrogen as building blocks for the manufacture of amidocarbonylation products. The amidocarbonylation reaction offers a convenient method to construct two functionalities - amido and carboxylate - simultaneously. Texaco has extended this chemistry to make a variety of speciality chemicals by tailoring cobalt catalysts. Products which have been made including: surface active agents such as the C{sub 14} - C{sub 16} alkyl amidoacids; surfactants; intermediates for sweeteners like aspartame; food additives like glutamic acid; and chelating agents such as polyamidoacids. 20 refs., 10 figs., 1 tab.

  7. Optimal control for chemical engineers

    CERN Document Server

    Upreti, Simant Ranjan

    2013-01-01

    Optimal Control for Chemical Engineers gives a detailed treatment of optimal control theory that enables readers to formulate and solve optimal control problems. With a strong emphasis on problem solving, the book provides all the necessary mathematical analyses and derivations of important results, including multiplier theorems and Pontryagin's principle.The text begins by introducing various examples of optimal control, such as batch distillation and chemotherapy, and the basic concepts of optimal control, including functionals and differentials. It then analyzes the notion of optimality, de

  8. Radiation treatment of toxic chemicals

    International Nuclear Information System (INIS)

    Polychlorinated biphenyls (PCBs) were commercially produced from 1920s as complex mixtures containing multiple isomers for a variety of applications. They are very toxic, chemically stable and resist microbial, photochemical, chemical, and thermal degradation. The public, legal, and scientific concerns about PCBs arose from research indicating they were environmental contaminants that had a potential to adversely impact the environment, and, therefore, were undesirable as commercial products. Eventually, most producers reduced or stopped production of PCBs in the 1970s. Stockholm convention on POPs (Persistent Organic Pollutants), which was effective on May 2004 and 151 nations including Korea were joined on June 2005, asked to dispose of PCBs by 2028 with environmental friendly methods. Korean government also has declared to conduct by 2015. According to the Environmental law of Korea, over 2 ppm of PCBs has to be decomposed by legal methods of incineration and thermal destruction. But those are inapplicable owing to the environmental groups. KAERI(Korea Atomic Energy Research Institute) has recently developed a remarkable technology for radiation treatment of toxic chemicals including chlorides using an electron beam accelerator. Electron beam accelerator of 2.5 MeV energy and 100 kW power capacity was used to decompose of PCBs having been used as a commercial transformer oil for more than 30 years. The oil were irradiated with ∼ 0.1 percent of TEA (Triethyl Amin) to make chloride ion aparted off from the PCBs into precipitate at the conditions of normal temperature and pressure. The concentrations of PCBs were measured by GC (Gas Chromatography) with ECD (Electron Capture Detector) following the KS (Korean Standard) test procedure. Electron beam should be a useful tool for environmental conservation. Residual concentrations of PCBs after irradiation were depended on the absorption dose of electron beam energy. Advantages comparing to other methods such as

  9. Chemical kinetics and combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  10. Chemical History with a Nuclear Microprobe

    OpenAIRE

    Maggiore, C. J.; Benjamin, T. M.; Hyde, P. J.; Rogers, P. S. Z.; Srinivasan, S; Tesmer, J.; Woolum, D. S.; Burnett, D. S.

    1983-01-01

    A nuclear microprobe cannot give direct information on the chemical state of an element, but the spatial distribution of elements in a specimen is often determined by the chemical history of the sample. Fuel cells and minerals are examples of complex systems whose elemental distributions are determined by past chemical history. The distribution of catalyst in used fuel cell electrodes provides direct information on the chemical stability of dispersed catalysts under operating conditions. We h...

  11. Opportunities for Merging Chemical and Biological Synthesis

    OpenAIRE

    Wallace, Stephen; Balskus, Emily P.

    2014-01-01

    Organic chemists and metabolic engineers use largely orthogonal technologies to access small molecules like pharmaceuticals and commodity chemicals. As the use of biological catalysts and engineered organisms for chemical production grows, it is becoming increasingly evident that future efforts for chemical manufacture will benefit from the integration and unified expansion of these two fields. This review will discuss approaches that combine chemical and biological synthesis for small molecu...

  12. An Experiment on Mining Chemical Reaction Databases

    OpenAIRE

    Berasaluce, Sandra; Laurenço, Claude; Napoli, Amedeo; Niel, Gilles

    2004-01-01

    In this paper, we present an experiment on knowledge discovery in chemical reaction databases. Chemical reactions are the main elements on which relies synthesis in organic chemistry, and this is why chemical reactions databases are of first importance. From a problem-solving process perspective, synthesis in organic chemistry must be considered at several levels of abstraction: mainly a strategic level where general synthesis methods are involved, and a tactic level where actual chemical rea...

  13. A Source Book for Teaching Chemical Oceanography.

    Science.gov (United States)

    Loder, Theodore C.; Glibert, Patricia M.

    Chemical oceanography or marine chemistry are taught in many colleges and universities. This publication provides sources for instructors of such courses. The first section of this report is a detailed composite outline of a course in chemical oceanography. It includes fundamental topics taught in many chemical oceanography classes. The outline…

  14. Experimental Demonstrations in Teaching Chemical Reactions.

    Science.gov (United States)

    Hugerat, Muhamad; Basheer, Sobhi

    2001-01-01

    Presents demonstrations of chemical reactions by employing different features of various compounds that can be altered after a chemical change occurs. Experimental activities include para- and dia-magnetism in chemical reactions, aluminum reaction with base, reaction of acid with carbonates, use of electrochemical cells for demonstrating chemical…

  15. Critical reflections on the Chemical Leasing concept

    NARCIS (Netherlands)

    Lozano, Rodrigo; Carpenter, Angela; Lozano, Francisco J.

    2014-01-01

    Chemical Leasing has been developed as a collaborative business model to complement the two main approaches (policy initiatives and scientific/ technological) used to foster green chemistry and sustainable chemistry. Chemical Leasing is based on using chemicals more efficiently, reducing waste, and

  16. Linking algal growth inhibition to chemical activity

    DEFF Research Database (Denmark)

    Schmidt, Stine N.; Mayer, Philipp

    chemical activity, as opposed to e.g. the total concentration. Baseline toxicity (narcosis) for neutral hydrophobic organic compounds has been shown to initiate in the narrow chemical activity range of 0.01 to 0.1. This presentation focuses on linking algal growth inhibition to chemical activity with the...

  17. 40 CFR 720.85 - Chemical identity.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chemical identity. 720.85 Section 720... PREMANUFACTURE NOTIFICATION Confidentiality and Public Access to Information § 720.85 Chemical identity. (a... submits information to EPA under this part may assert a claim of confidentiality for the chemical...

  18. Experiments To Demonstrate Chemical Process Safety Principles.

    Science.gov (United States)

    Dorathy, Brian D.; Mooers, Jamisue A.; Warren, Matthew M.; Mich, Jennifer L.; Murhammer, David W.

    2001-01-01

    Points out the need to educate undergraduate chemical engineering students on chemical process safety and introduces the content of a chemical process safety course offered at the University of Iowa. Presents laboratory experiments demonstrating flammability limits, flash points, electrostatic, runaway reactions, explosions, and relief design.…

  19. Schools Remove Hazardous Chemicals from Labs.

    Science.gov (United States)

    Chemical and Engineering News, 1982

    1982-01-01

    Describes safety committee (New York section, American Chemical Society) survey of college chemistry facilities to assess hazards and make recommendations, and a cooperative project in Iowa to identify and remove hazardous chemicals from college/secondary school classrooms. Includes a partial list of hazardous chemicals identified by the Iowa…

  20. Disruptive chemicals, senescence and immortality.

    Science.gov (United States)

    Carnero, Amancio; Blanco-Aparicio, Carmen; Kondoh, Hiroshi; Lleonart, Matilde E; Martinez-Leal, Juan Fernando; Mondello, Chiara; Scovassi, A Ivana; Bisson, William H; Amedei, Amedeo; Roy, Rabindra; Woodrick, Jordan; Colacci, Annamaria; Vaccari, Monica; Raju, Jayadev; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Salem, Hosni K; Memeo, Lorenzo; Forte, Stefano; Singh, Neetu; Hamid, Roslida A; Ryan, Elizabeth P; Brown, Dustin G; Wise, John Pierce; Wise, Sandra S; Yasaei, Hemad

    2015-06-01

    Carcinogenesis is thought to be a multistep process, with clonal evolution playing a central role in the process. Clonal evolution involves the repeated 'selection and succession' of rare variant cells that acquire a growth advantage over the remaining cell population through the acquisition of 'driver mutations' enabling a selective advantage in a particular micro-environment. Clonal selection is the driving force behind tumorigenesis and possesses three basic requirements: (i) effective competitive proliferation of the variant clone when compared with its neighboring cells, (ii) acquisition of an indefinite capacity for self-renewal, and (iii) establishment of sufficiently high levels of genetic and epigenetic variability to permit the emergence of rare variants. However, several questions regarding the process of clonal evolution remain. Which cellular processes initiate carcinogenesis in the first place? To what extent are environmental carcinogens responsible for the initiation of clonal evolution? What are the roles of genotoxic and non-genotoxic carcinogens in carcinogenesis? What are the underlying mechanisms responsible for chemical carcinogen-induced cellular immortality? Here, we explore the possible mechanisms of cellular immortalization, the contribution of immortalization to tumorigenesis and the mechanisms by which chemical carcinogens may contribute to these processes. PMID:26106138

  1. Pickering Unit 1 chemical cleaning

    International Nuclear Information System (INIS)

    The secondary sides of all 12 boilers at Pickering Unit 1 were chemically cleaned in 1994 by the team of Ontario Hydro, B and W International (Cambridge, Ontario) and B and W Nuclear Technologies (Lynchburg, Virginia). A multi-step EPRI/SGOG process was employed in a similar manner to previous clearings at Units 5 and 6 in 1992 and 1993, respectively. A major innovation with the Unit 1 cleaning was the incorporation of a crevice cleaning step, the first time this had been done on Ontario Hydro plants. In addition, six boilers were cleaned in parallel compared to three at a time in previous Pickering cleanings. This significantly reduced cleaning time. A total of 6,770 kg of sludge was removed through direct chemical dissolution. It consisted of 66% iron/nickel oxides and 28% copper metal. A total of 1,600,000 L (420,000 US gallons) of liquid waste was produced. It was processed through the spent solvent treatment facility located at the Bruce Nuclear Power Development site. Visual inspection performed after the cleaning indicated that the crevices between the boiler tubes and the tube support structure were completely clear of deposit and the general condition of the tubing and lattice bars appeared to be in 'as new' condition. (author)

  2. The Chemical Evolution of Phosphorus

    CERN Document Server

    Jacobson, Heather R; Frebel, Anna; Roederer, Ian U; Cescutti, Gabriele; Matteucci, Francesca

    2014-01-01

    Phosphorus is one of the few remaining light elements for which little is known about its nucleosynthetic origin and chemical evolution, given the lack of optical absorption lines in the spectra of long-lived FGK-type stars. We have identified a P I doublet in the near-ultraviolet (2135/2136 A) that is measurable in stars of low metallicity. Using archival Hubble Space Telescope-STIS spectra, we have measured P abundances in 13 stars spanning -3.3 <= [Fe/H] <= -0.2, and obtained an upper limit for a star with [Fe/H] ~ -3.8. Combined with the only other sample of P abundances in solar-type stars in the literature, which spans a range of -1 <= [Fe/H] <= +0.2, we compare the stellar data to chemical evolution models. Our results support previous indications that massive-star P yields may need to be increased by a factor of a few to match stellar data at all metallicities. Our results also show that hypernovae were important contributors to the P production in the early universe. As P is one of the ke...

  3. Air corona discharge chemical kinetics

    International Nuclear Information System (INIS)

    We have theoretically studied the initial chemical processing steps which occur in pulseless, negative, dc corona discharges in flowing air. A rate equation model is used because these discharges consist of a very small ionization zone near the pin with most of the pin-plane gap filled by a drift zone where both the electric field and the electron density are relatively uniform. The primary activated species are N2(A),O and O2(a1Δ). The predicted activated species density due to one discharge is 100 ppm per ms . mA cm2 assuming E/n=60 Td. In pure, dry air the final product due to these activated species is primarily O3. The NO /sub x/ production is about 0.5 ppm per mA. In moist air there is an additional production of about 1.5 ppm per mA of HO /sub x/ species. The predicted ozone formation reactions will be ''intercepted'' when impurities are present in the air. Impurities present at densities below about 0.1% will react primarily with the activated species rather than with electrons. Hence the predicted activated species density provides an estimate of the potential chemical processing performance of the discharge

  4. Toxicological evaluation of chemical mixtures.

    Science.gov (United States)

    Feron, V J; Groten, J P

    2002-06-01

    This paper addresses major developments in the safety evaluation of chemical mixtures during the past 15 years, reviews today's state of the art of mixture toxicology, and discusses challenges ahead. Well-thought-out tailor-made mechanistic and empirical designs for studying the toxicity of mixtures have gradually substituted trial-and-error approaches, improving the insight into the testability of joint action and interaction of constituents of mixtures. The acquired knowledge has successfully been used to evaluate the safety of combined exposures and complex mixtures such as, for example, the atmosphere at hazardous waste sites, drinking water disinfection by-products, natural flavouring complexes, and the combined intake of food additives. To consolidate the scientific foundation of mixture toxicology, studies are in progress to revisit the biological concepts and mathematics underlying formulas for low-dose extrapolation and risk assessment of chemical mixtures. Conspicuous developments include the production of new computer programs applicable to mixture research (CombiTool, BioMol, Reaction Network Modelling), the application of functional genomics and proteomics to mixture studies, the use of nano-optochemical sensors for in vivo imaging of physiological processes in cells, and the application of optical sensor micro- and nano-arrays for complex sample analysis. Clearly, the input of theoretical biologists, biomathematicians and bioengineers in mixture toxicology is essential for the development of this challenging branch of toxicology into a scientific subdiscipline of full value. PMID:11983277

  5. Chemical Characterization of Marajoara Pottery

    International Nuclear Information System (INIS)

    The aim of this project was to find a fingerprinting of the archaeological Marajoara pottery. For that, 330 archaeological and 36 contemporary samples were analysed using two techniques: INAA for elemental chemical analysis and ESR (Electron spin resonance) to determine the burning temperature. The results were studied by means of principal component and discriminant analysis using the SEARCH Programme from H. Mommsen from University of Bonn, Germany, showed the existence of two groups for the archaeological samples indicating that different raw material was used in the manufacturing of the prehistoric artifacts. Meanwhile, the clay used in the contemporary Marajoara ceramics is very different from the clay used in the archaeological. The temper effect in the concentration data was studied by means of correlation coefficient and showed that the tempering problem does not exist in the ceramics. The Procrustes analysis showed that the reduction of variable is viable and the chemical elements Eu, K, Yb, Cr, Fe and Th are sufficient in order to do the fingerprinting of the Marajoara pottery. The ESR studies showed that there is no difference in the burning temperature between the Marajoara's ceramics (the archaeological and contemporary ones). This Project was made in collaboration with the Museu de Arquelogia e Etnologia da Universidade de Sao Paulo, Sao Paulo, Brazil and University of Bonn, Germany by means a fellowship of IAEA in the training on the use of the SEARCH Programme. (author)

  6. User needs in chemical information

    International Nuclear Information System (INIS)

    Information has become an absolutely indispensable factor in the modern industrial society. In chemistry, detailed information about all compounds known is required. Learned journals, research and conference reports, publications from universities and learned societies, and dissertations present the progress in research. It is important that all properties of compounds (stereochemistry, physical values, chemical and environmental behaviour, toxicity etc.) reported in these publications be indexed and made available to the users. There is also a need for factual and/or numerical data and reviews concerning general or specific topics. High on the list of desiderata are timeliness, accuracy and completeness of the information. Abstracting and indexing services and database producers have to take in consideration that a high degree of userfriendliness is necessary. In the future, most of the information will be offered in computer readable form (factual and numerical databases, reaction databases, information on CD-ROM etc.), a fact which will require many improvements in the flow of information in order to render possible an easy and direct access to the chemical information worldwide. (author). 15 refs

  7. Cosmic chemical memory: a new astronomy

    International Nuclear Information System (INIS)

    An account is presented of the study of the chemical evolution of the Galaxy through measurements on meteoritic samples in terrestrial laboratories. This includes the evolution of the chemical forms within the interstellar medium and of the isotopic structures that they contain. The measuring techniques described include mass spectrometry, microscopic chemical analysis, and chemical concentration in residues. Astrophysical topics under observation in the chemical constitution of meteoritic samples are discussed under the headings: nucleosynthesis; origin and evolution of interstellar dust; origin of the solar system; interstellar conditions and history. (U.K.)

  8. Assessment of chemicals in construction products

    DEFF Research Database (Denmark)

    Krogh, Hanne; Olsen, Stig Irving

    2000-01-01

    . The reasons for that are lacks of product-specific emissions by manufacturing of chemical products, e.g. waterproofing systems and sealants. Besides, most LCA-models do not include assessments of emissions in working environment, in indoor environment or from disposal processes. It was therefore in...... the project Assessment of Chemicals in Construction Products decided to adapt an existing score method for assessing the chemicals. As the European countries had agreed on a score Method for Risk Ranking chemicals (EURAM), it was decided to use this method to assess chemicals in construction products...

  9. Chemical reactions at aqueous interfaces

    Science.gov (United States)

    Vecitis, Chad David

    2009-12-01

    Interfaces or phase boundaries are a unique chemical environment relative to individual gas, liquid, or solid phases. Interfacial reaction mechanisms and kinetics are often at variance with homogeneous chemistry due to mass transfer, molecular orientation, and catalytic effects. Aqueous interfaces are a common subject of environmental science and engineering research, and three environmentally relevant aqueous interfaces are investigated in this thesis: 1) fluorochemical sonochemistry (bubble-water), 2) aqueous aerosol ozonation (gas-water droplet), and 3) electrolytic hydrogen production and simultaneous organic oxidation (water-metal/semiconductor). Direct interfacial analysis under environmentally relevant conditions is difficult, since most surface-specific techniques require relatively `extreme' conditions. Thus, the experimental investigations here focus on the development of chemical reactors and analytical techniques for the completion of time/concentration-dependent measurements of reactants and their products. Kinetic modeling, estimations, and/or correlations were used to extract information on interfacially relevant processes. We found that interfacial chemistry was determined to be the rate-limiting step to a subsequent series of relatively fast homogeneous reactions, for example: 1) Pyrolytic cleavage of the ionic headgroup of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) adsorbed to cavitating bubble-water interfaces during sonolysis was the rate-determining step in transformation to their inorganic constituents carbon monoxide, carbon dioxide, and fluoride; 2) ozone oxidation of aqueous iodide to hypoiodous acid at the aerosol-gas interface is the rate-determining step in the oxidation of bromide and chloride to dihalogens; 3) Electrolytic oxidation of anodic titanol surface groups is rate-limiting for the overall oxidation of organics by the dichloride radical. We also found chemistry unique to the interface, for example: 1

  10. Predictive toxicology of chemicals and database mining

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The toxic chemicals from the database Registry of Toxic Effects of Chemical Substances (RTECS) were analyzed by structural similarity comparison, which shows that the structure patterns or characteristics of toxic chemicals exist in a sufficiently large database. Then, a two-step strategy was proposed to explore noncongeneric toxic chemicals in the database: the screening of structure patterns by similarity comparison and the derivation of detailed relationship between structure and activity by using comparative molecular field analysis (CoMFA) of Quantitative Structure-Activity Relationship (QSAR) technologies. From the performance of the procedure, such a stepwise scheme is demonstrated to be feasible and effective to mine a database of toxic chemicals. It can be anticipated that database mining of toxic chemicals will be a new area for predictive toxicology of chemicals.

  11. Fixed Points for Stochastic Open Chemical Systems

    CERN Document Server

    Malyshev, V A

    2011-01-01

    In the first part of this paper we give a short review of the hierarchy of stochastic models, related to physical chemistry. In the basement of this hierarchy there are two models --- stochastic chemical kinetics and the Kac model for Boltzman equation. Classical chemical kinetics and chemical thermodynamics are obtained as some scaling limits in the models, introduced below. In the second part of this paper we specify some simple class of open chemical reaction systems, where one can still prove the existence of attracting fixed points. For example, Michaelis\\tire Menten kinetics belongs to this class. At the end we present a simplest possible model of the biological network. It is a network of networks (of closed chemical reaction systems, called compartments), so that the only source of nonreversibility is the matter exchange (transport) with the environment and between the compartments. Keywords: chemical kinetics, chemical thermodynamics, Kac model, mathematical biology

  12. A multivariate chemical map of industrial chemicals--assessment of various protocols for identification of chemicals of potential concern.

    Science.gov (United States)

    Stenberg, Mia; Linusson, Anna; Tysklind, Mats; Andersson, Patrik L

    2009-08-01

    In present study the Industrial chemical map was created, and investigated. Molecular descriptors were calculated for 56072 organic substances from the European inventory of existing commercial chemical substances (EINECS). The resulting multivariate dataset was subjected to principal component analysis (PCA), giving five principal components, mainly reflecting size, hydrophobicity, flexibility, halogenation and electronical properties. It is these five PCs that form the basis of the map of organic, industrial chemicals, the Industrial chemical map. The similarities and diversity in chemical characteristics of the substances in relation to their persistence (P), bioaccumulation (B) and long-range transport potential were then examined, by superimposing five sets of entries obtained from other relevant databases onto the Industrial chemical map. These sets displayed very similar diversity patterns in the map, although with a spread in all five PC vectors. Substances listed by the United Nations Environment Program as persistent organic pollutants (UNEP POPs) were on the other hand clearly grouped with respect to each of the five PCs. Illustrating similarities and differences in chemical properties are one of the strengths of the multivariate data analysis method, and to be able to make predictions of, and investigate new chemicals. Further, the results demonstrate that non-testing methods as read-across, based on molecular similarities, can reduce the requirements to test industrial chemicals, provided that they are applied carefully, in combination with sound chemical knowledge. PMID:19515399

  13. Coacervates as prebiotic chemical reactors

    Science.gov (United States)

    Kolb, Vera M.; Swanson, Mercedes; Menger, Fredric M.

    2012-10-01

    Coacervates are colloidal systems that are comprised of two immiscible aqueous layers, the colloid-rich layer, so-called coacervate, and the colloid-poor layer, so-called equilibrium liquid. Although immiscible, the two phases are both water-rich. Coacervates are important for prebiotic chemistry, but also have various practical applications, notably as transport vehicles of personal care products and pharmaceuticals. Our objectives are to explore the potential of coacervates as prebiotic chemical reactors. Since the reaction medium in coacervates is water, this creates a challenge, since most organic reactants are not water-soluble. To overcome this challenge we are utilizing recent Green Chemistry examples of the organic reactions in water, such as the Passerini reaction. We have investigated this reaction in two coacervate systems, and report here our preliminary results.

  14. Information Extraction From Chemical Patents

    Directory of Open Access Journals (Sweden)

    Sandra Bergmann

    2012-01-01

    Full Text Available The development of new chemicals or pharmaceuticals is preceded by an indepth analysis of published patents in this field. This information retrieval is a costly and time inefficient step when done by a human reader, yet it is mandatory for potential success of an investment. The goal of the research project UIMA-HPC is to automate and hence speed-up the process of knowledge mining about patents. Multi-threaded analysis engines, developed according to UIMA (Unstructured Information Management Architecture standards, process texts and images in thousands of documents in parallel. UNICORE (UNiform Interface to COmputing Resources workflow control structures make it possible to dynamically allocate resources for every given task to gain best cpu-time/realtime ratios in an HPC environment.

  15. Polyfluorinated chemicals and transformation products

    Energy Technology Data Exchange (ETDEWEB)

    Knepper, Thomas P. [Univ. of Applied Sciences Fresenius, Idstein (Germany). Inst. for Analytical Research; Lange, Frank Thomas (eds.) [DVGW-Technologiezentrum Wasser, Karlsruhe (Germany)

    2012-07-01

    Due to their unparalleled effectiveness and efficiency, polyfluorinated chemicals (PFC) have become essential in numerous technical applications. However, many PFCs brought to market show limited biodegradability, and their environmental persistence combined with toxic and bioaccumulative potential have become a matter of concern in some instances. This volume highlights the synthesis of PFCs, focusing on substances with improved application and environmental properties, which are a challenge for synthetic chemists. Further, modern mass spectrometric techniques for the detection and identification of biotransformation products of PFCs are described. The sorption and leaching behavior of PFC in soil is also addressed in order to predict their fate in the environment. Several contributions discuss the monitoring of PFCs in European surface, ground and drinking waters, treatment options for PFC removal from drinking water, occurrence in food, and the human biomonitoring of PFCs. (orig.)

  16. Chemical compass for bird navigation

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Hore, Peter J.; Ritz, Thorsten;

    2014-01-01

    Migratory birds travel spectacular distances each year, navigating and orienting by a variety of means, most of which are poorly understood. Among them is a remarkable ability to perceive the intensity and direction of the Earth's magnetic field. Biologically credible mechanisms for the detection...... other relies on the quantum spin dynamics of transient photoinduced radical pairs. Originally suggested by Schulten in 1978 as the basis of the avian magnetic compass sensor, this mechanism gained support from the subsequent observation that the compass is light-dependent. The radical pair hypothesis...... began to attract increased interest following the proposal in 2000 that free radical chemistry could occur in the bird's retina initiated by photoexcitation of cryptochrome, a specialized photoreceptor protein. In the present paper we review the important physical and chemical constraints on a possible...

  17. Fuel-cladding chemical interaction

    International Nuclear Information System (INIS)

    The chemistry of the nuclear fuel is very complex. Its chemical composition changes with time due to the formation of fission products and depends on the temperature level history within the fuel pellet and the clad during operation. Firstly, in thermal reactors, zircaloy oxidation from reaction with UO2 fuel under high-temperature conditions will be addressed. Then other fuel-cladding interaction phenomena occurring in fast reactors will be described. Large thermal gradients existing between the centre and the periphery of the pellet induce the radial redistribution of the fuel constituents. The fuel pellet can react with the clad by different corrosion processes which can involve actinide and/or fission product transport via gas, liquid or/and solid phases. All these phenomena are briefly described in the case of different kinds of fuels (oxide, carbide, nitride, metallic) to be used in fast reactors. The way these phenomena are taken into account in fuel performance codes is presented. (authors)

  18. Chemical analysis by nuclear techniques

    International Nuclear Information System (INIS)

    This state art report consists of four parts, production of micro-particles, analysis of boron, alpha tracking method and development of neutron induced prompt gamma ray spectroscopy (NIPS) system. The various methods for the production of micro-paticles such as mechanical method, electrolysis method, chemical method, spray method were described in the first part. The second part contains sample treatment, separation and concentration, analytical method, and application of boron analysis. The third part contains characteristics of alpha track, track dectectors, pretreatment of sample, neutron irradiation, etching conditions for various detectors, observation of track on the detector, etc. The last part contains basic theory, neutron source, collimator, neutron shields, calibration of NIPS, and application of NIPS system

  19. Chemical Models of Collapsing Envelopes

    CERN Document Server

    Bergin, E A

    1999-01-01

    We discuss recent models of chemical evolution in the developing and collapsing protostellar envelopes associated with low-mass star formation. In particular, the effects of depletion of gas-phase molecules onto grain surfaces is considered. We show that during the middle to late evolutionary stages, prior to the formation of a protostar, various species selectively deplete from the gas phase. The principal pattern of selective depletions is the depletion of sulfur-bearing molecules relative to nitrogen-bearing species: NH3 and N2H+. This pattern is shown to be insensitive to the details of the dynamics and marginally sensitive to whether the grain mantle is dominated by polar or non-polar molecules. Based on these results we suggest that molecular ions are good tracers of collapsing envelopes. The effects of coupling chemistry and dynamics on the resulting physical evolution are also examined. Particular attention is paid to comparisons between models and observations.

  20. Olefin metathesis for chemical biology.

    Science.gov (United States)

    Binder, Joseph B; Raines, Ronald T

    2008-12-01

    Chemical biology relies on effective synthetic chemistry for building molecules to probe and modulate biological function. Olefin metathesis in organic solvents is a valuable addition to this armamentarium, and developments during the previous decade are enabling metathesis in aqueous solvents for the manipulation of biomolecules. Functional group-tolerant ruthenium metathesis catalysts modified with charged moieties or hydrophilic polymers are soluble and active in water, enabling ring-opening metathesis polymerization, cross metathesis, and ring-closing metathesis. Alternatively, conventional hydrophobic ruthenium complexes catalyze a similar array of metathesis reactions in mixtures of water and organic solvents. This strategy has enabled cross metathesis on the surface of a protein. Continuing developments in catalyst design and methodology will popularize the bioorthogonal reactivity of metathesis. PMID:18935975

  1. Chemical characteristic of respirable particulates

    International Nuclear Information System (INIS)

    Respirable particulates are particulates which having diameter size at 2-5 µm, due to aerodynamically may be inhaled through respiratory tract and having ability to deposit into lungs, causing damage of the alveolar tissues and inducing health problems. Health Department of Bandung have reported that prevalency of acute respiratory tract infection disease having increasing tendency every year. Measurement of PM10 in period of 2002-2005 have done by BPLH Bandung city which pointed that in some places the concentration of PM10 was higher than daily threshold limit values. This research having intend to understand of respirable particulates exposure in society with characterization of chemical materials contained as hazard identification. Location of research have done in four regions of Bandung City. Personal sampler has used for collection of respirable particulates from human breathing zone. Chemical characteristic were done using neutron activation analysis, atomic absorption spectrometer and reflectance methods. The useful of this procedure as the baseline to calculate IEC (Inhalation Exposure Concentration) values for estimate the exposure of respirable particulates which inhaled during period of time. Calculating of IEC is the earlier step from epidemiological study or risk assessment which connecting prevalency of tract respiratory disease with characteristic of respirable particulates. Elements Br, Mn, Al, I, V, Cl, Ti, Na, Hg, Pb, and black carbon (BC), are the elements which identified. The results showed that respirable particulates which inhaled by citizen as receptor at Tegalega, Aria Graha, Dago Pakar, and Cisaranten Wetan are relatively higher than PM2,5 ambient air at the same places. Almost whole of such elements which contained in respirable particulates was found in highest concentration at Cisaranten Wetan. (author)

  2. Chemical aspects of irradiated mangoes

    International Nuclear Information System (INIS)

    Mango is an important and very popular tropical fruit. Because of its short shelf life, however, its use is restricted to the areas of production. Since mango is a climacteric fruit, it is possible to extend its shelf life by delaying the ripening process and senescence by irradiation. The ripening process is very complex: it appears that the radiation-induced delay in ripening may be mediated through the inhibition of the enzyme(s) involved in ethylene production. The dose required for shelf-life extension is ≤1.5 kGy. Higher doses can lead to scalding, flesh darkening and development of hollow pockets. This review focuses on the chemical aspects of radiation-induced shelf-life extension of mangoes. At the low irradiation doses required for this shelf-life extension (≤1.5 kGy), the chemical effects are negligible. Irradiation does not affect the carotenoid levels, and has only a minor effect on the vitamin C level in a few mango varieties. No significant differences in the free and total (hydrolyzed) amino acids, or the protein content of Kent mangoes, have been detected between irradiated and unirradiated samples. During ripening of the mangoes the reducing sugar and the total sugar levels increase, but in the majority of the mango varieties these levels remain very similar in irradiated and unirradiated samples. There are some differences in the volatile compounds between irradiated and unirradiated Kent mangoes; however, these differences have no apparent effect on the taste and flavor of the irradiated mangoes

  3. Chemical Reactivity as Described by Quantum Chemical Methods

    Directory of Open Access Journals (Sweden)

    F. De Proft

    2002-04-01

    Full Text Available Abstract: Density Functional Theory is situated within the evolution of Quantum Chemistry as a facilitator of computations and a provider of new, chemical insights. The importance of the latter branch of DFT, conceptual DFT is highlighted following Parr's dictum "to calculate a molecule is not to understand it". An overview is given of the most important reactivity descriptors and the principles they are couched in. Examples are given on the evolution of the structure-property-wave function triangle which can be considered as the central paradigm of molecular quantum chemistry to (for many purposes a structure-property-density triangle. Both kinetic as well as thermodynamic aspects can be included when further linking reactivity to the property vertex. In the field of organic chemistry, the ab initio calculation of functional group properties and their use in studies on acidity and basicity is discussed together with the use of DFT descriptors to study the kinetics of SN2 reactions and the regioselectivity in Diels Alder reactions. Similarity in reactivity is illustrated via a study on peptide isosteres. In the field of inorganic chemistry non empirical studies of adsorption of small molecules in zeolite cages are discussed providing Henry constants and separation constants, the latter in remarkable good agreement with experiments. Possible refinements in a conceptual DFT context are presented. Finally an example from biochemistry is discussed : the influence of point mutations on the catalytic activity of subtilisin.

  4. Isotope separation by chemical exchange

    International Nuclear Information System (INIS)

    Nitrogen-15 and oxygen-18 enrichment by chemical exchange in the (NO/NO2) - (H2O/HNO3) system, using a laboratory-scale experimental plant and a cascade for production of two isotopes, is presented. The results obtained from the laboratory-scale plant indicate that optimal flow rate for 15N separation is 1.55 - 1.86 ml/cm2 · min at 8 - 10 M/l nitric acid and 63.4 mg at. oxygen/cm2 · min for 18O separation at 5.8 M/l nitric acid. The height equivalent to a theoretical plate (HETP) of 4.11 - 4.56 cm is in good agreement with other published data for 15N separation using exchange column with Helipak packing. The HETP of 7.74 - 10.58 cm for 18O separation is greater by 20 - 30 % than those presented by Saxena and Taylor for 'Helipak' column packing, but in good agreement with the HRTP published by Borisov et al. on 'Levina' column packing. The HETP obtained for 15N separation by the production plant is in the range 11.5 - 13.8 cm at a flow rate of 2.2 ml HNO3(10M/l)/cm2 · min for the first column and 4.4 - 4.7 cm at a flow rate of 1.66 ml HNO3(10M/l)/cm2 · min for the second column. The optimal flow rate for 18O separation by the production plant is about 63 mg at. oxygen/cm2 · min (1.01 ml HNO3/cm2 · min). Enrichment of 13C and 18O by chemical exchange of carbon dioxide with its monoethanolamine carbamate in methanol and di-n-butylamine carbamate in triethylamine has also been studied, and optimum operating conditions for the separation of 13C in a packed column was determined. The HETP obtained for the 13C in a packed column was determined. The HETP obtained for the 13C separation column is 3.62 - 8.26 cm at a flow rate of 1.1 - 4.0 mmol carbamate/cm2 · min using the same column packing as for 15N and 18O separation, that is, stainless steel triangular wire springs (2.3 x 2.3 x 0.2 mm). (author)

  5. Low thrust chemical rocket technology

    Science.gov (United States)

    Schneider, Steven J.

    1992-01-01

    An on-going technology program to improve the performance of low thrust chemical rockets for spacecraft on-board propulsion applications is reviewed. Improved performance and lifetime is sought by the development of new predictive tools to understand the combustion and flow physics, introduction of high temperature materials and improved component designs to optimize performance, and use of higher performance propellants. Improved predictive technology is sought through the comparison of both local and global predictions with experimental data. Predictions are based on both the RPLUS Navier-Stokes code with finite rate kinetics and the JANNAF methodology. Data were obtained with laser-based diagnostics along with global performance measurements. Results indicate that the modeling of the injector and the combustion process needs improvement in these codes and flow visualization with a technique such as 2-D laser induced fluorescence (LIF) would aid in resolving issues of flow symmetry and shear layer combustion processes. High temperature material fabrication processes are under development and small rockets are being designed, fabricated, and tested using these new materials. Rhenium coated with iridium for oxidation protection was produced by the Chemical Vapor Deposition (CVD) process and enabled an 800 K increase in rocket operating temperature. Performance gains with this material in rockets using Earth storable propellants (nitrogen tetroxide and monomethylhydrazine or hydrazine) were obtained through component redesign to eliminate fuel film cooling and its associated combustion inefficiency while managing head end thermal soakback. Material interdiffusion and oxidation characteristics indicated that the requisite lifetimes of tens of hours were available for thruster applications. Rockets were designed, fabricated, and tested with thrusts of 22, 62, 440 and 550 N. Performance improvements of 10 to 20 seconds specific impulse were demonstrated. Higher

  6. Chemical warfare, past and future. Study project

    Energy Technology Data Exchange (ETDEWEB)

    Tzihor, A.

    1992-05-15

    World War I was arena for the first use of chemical warfare. The enormous tactical success brought about by this first time use of chemical weapons caused the continued development of more sophisticated tactics and weapons in this category of unconventional warfare. This phenomenon has carried through to today. However, at present, because of technological developments, the global economic situation, and political factors, coupled with the inability of the western world to control the proliferation of chemical weapons, a situation weapon of mass destruction. Recent use by Iraq against Kurdish civilian indicates that chemical warfare is no longer limited to the battlefield. The western nations have a need to understand the risk. This paper conducts an analysis of past lessons and the factors which will affect the use of chemical warfare in the future. From this analysis, the paper reaches conclusions concerning the significant threat chemical weapons pose for the entire world in the not too distant future.

  7. Future market aspects of oilfield specialty chemicals

    International Nuclear Information System (INIS)

    The oilfield specialty chemical market has undergone many changes over the past 10 years. Looking back to 1980-1981, the oilfield chemical market was robust as oilfield activity was peaking at 4,500 rigs in the U.S. and 5,800 rigs worldwide. At that time, a fever-pitched industry sought new specialty chemicals for improved drilling, completion and workover, cementing, stimulation, production, and particularly enhanced oil recovery (EOR) techniques. After all, crude oil was reaching $40/barrel and the outlook showed $100/barrel by the end of the decade. Complicating matters, however, was the fact that while higher oil and gas prices were spurring oilfield activity they were also pushing the world into a recession. And, as commodity chemical usage was declining rapidly, many chemical companies, seeking relief from the cyclicality of commodity products, ventured into the oilfield specialty chemical segment. (Author)

  8. Comparison of radiation and chemical risks

    International Nuclear Information System (INIS)

    Injury to living cells is caused by mechanisms which in many cases are similar for radiation and chemicals. It is thus not surprising that radiation and many chemicals can cause similar biological effects, e.g. cancer, fetal injury and hereditary disease. Both radiation and chemicals are always found in our environment. One agent may strengthen or weaken the effect of another, be it radiation in combination with chemicals or one chemical with another. The implications of such synergistic or antagonistic effects are discussed. Intricate mechanisms help the body to defend itself against threats to health from radiation and chemicals, even against cancer risks. In a strategy for health, it might be worth to exploit actively these defense mechanisms, in parallel with decreasing the exposures. On particular interest are the large exposures from commonly known sources such as smoking, sun tanning and high fat contents of food. (author)

  9. Do open clusters have distinguishable chemical signatures?

    CERN Document Server

    Blanco-Cuaresma, S; Heiter, U

    2015-01-01

    Past studies have already shown that stars in open clusters are chemically homogeneous (e.g. De Silva et al. 2006, 2007 and 2009). These results support the idea that stars born from the same giant molecular cloud should have the same chemical composition. In this context, the chemical tagging technique was proposed by Freeman et al. 2002. The principle is to recover disrupted stellar clusters by looking only to the stellar chemical composition. In order to evaluate the feasibility of this approach, it is necessary to test if we can distinguish between stars born from different molecular clouds. For this purpose, we studied the chemical composition of stars in 32 old and intermediate-age open clusters, and we applied machine learning algorithms to recover the original cluster by only considering the chemical signatures.

  10. Electrostatic thin film chemical and biological sensor

    Science.gov (United States)

    Prelas, Mark A.; Ghosh, Tushar K.; Tompson, Jr., Robert V.; Viswanath, Dabir; Loyalka, Sudarshan K.

    2010-01-19

    A chemical and biological agent sensor includes an electrostatic thin film supported by a substrate. The film includes an electrostatic charged surface to attract predetermined biological and chemical agents of interest. A charge collector associated with said electrostatic thin film collects charge associated with surface defects in the electrostatic film induced by the predetermined biological and chemical agents of interest. A preferred sensing system includes a charge based deep level transient spectroscopy system to read out charges from the film and match responses to data sets regarding the agents of interest. A method for sensing biological and chemical agents includes providing a thin sensing film having a predetermined electrostatic charge. The film is exposed to an environment suspected of containing the biological and chemical agents. Quantum surface effects on the film are measured. Biological and/or chemical agents can be detected, identified and quantified based on the measured quantum surface effects.

  11. Endocrine Disrupting Chemicals and Disease Susceptibility

    OpenAIRE

    Schug, Thaddeus T.; Janesick, Amanda; Blumberg, Bruce; Heindel, Jerrold J.

    2011-01-01

    Environmental chemicals have significant impacts on biological systems. Chemical exposures during early stages of development can disrupt normal patterns of development and thus dramatically alter disease susceptibility later in life. Endocrine disrupting chemicals (EDCs) interfere with the body's endocrine system and produce adverse developmental, reproductive, neurological, cardiovascular, metabolic and immune effects in humans. A wide range of substances, both natural and man-made, are tho...

  12. Thyroid effects of endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Boas, Malene; Feldt-Rasmussen, Ulla; Main, Katharina M

    2012-01-01

    In recent years, many studies of thyroid-disrupting effects of environmental chemicals have been published. Of special concern is the exposure of pregnant women and infants, as thyroid disruption of the developing organism may have deleterious effects on neurological outcome. Chemicals may exert ...... thyroid-disrupting effects, and there is emerging evidence that also phthalates, bisphenol A, brominated flame retardants and perfluorinated chemicals may have thyroid disrupting properties....

  13. Flavour chemicals in electronic cigarette fluids

    OpenAIRE

    Tierney, Peyton A; Karpinski, Clarissa D; Jessica E Brown; Luo, Wentai; Pankow, James F.

    2015-01-01

    Background Most e-cigarette liquids contain flavour chemicals. Flavour chemicals certified as safe for ingestion by the Flavor Extracts Manufacturers Association may not be safe for use in e-cigarettes. This study identified and measured flavour chemicals in 30 e-cigarette fluids. Methods Two brands of single-use e-cigarettes were selected and their fluids in multiple flavour types analysed by gas chromatography/mass spectrometry. For the same flavour types, and for selected confectionary fla...

  14. Chemical composition of Earth-like planets

    OpenAIRE

    Ronco, M. P.; Thiabaud, A.; Marboeuf, U.; Alibert, Y.; de Elía, G. C.; O. M. Guilera

    2015-01-01

    Models of planet formation are mainly focused on the accretion and dynamical processes of the planets, neglecting their chemical composition. In this work, we calculate the condensation sequence of the different chemical elements for a low-mass protoplanetary disk around a solar-type star. We incorporate this sequence of chemical elements (refractory and volatile elements) in our semi-analytical model of planet formation which calculates the formation of a planetary system during its gaseous ...

  15. Chemical risk: strategies for social intervention

    OpenAIRE

    A. A. Calera Rubio; E. Estefanía Blount; J. Riechmann Fernández

    2002-01-01

    Production, use, marketing and emission of chemical substances display the strong links between chemical risks at the workplace, healthcare and environmental pollution. In spite of this fact, the policies for the management of chemical risk are far from being coherent and unified in the different sectors. (Nutritional safety, agriculture, healthcare, environment and occupational health).The Commission of European Communities (EC) has elaborated a White Document on the future policy on chemica...

  16. The Demand for Chemical Fertilizers in China

    OpenAIRE

    Peng, Daiyan; Kawaguchi, Tsunemasa

    2001-01-01

    During the past two decades, the tremendous increase in the use of chemical fertilizers compared with other inputs in Chinese agriculture is particularly impressive. This growing use of chemical fertilizers has played a crucial role Chinese agricultural growth. In the future, the use of chemical fertilizers will continue to play an unsubstitutably important role. As land become more scarce, the future growth of Chinese agriculture will mainly depend on technological progress like the adoption...

  17. Evolution of chemical abundances in Seyfert galaxies

    OpenAIRE

    Ballero, S. K.; Matteucci, F; Ciotti, L.; Calura, F; P. Padovani

    2007-01-01

    We computed the chemical evolution of spiral bulges hosting Seyfert nuclei, based on updated chemical and spectro-photometrical evolution models for the bulge of our Galaxy, made predictions about other quantities measured in Seyferts, and modeled the photometry of local bulges. The chemical evolution model contains detailed calculations of the Galactic potential and of the feedback from the central supermassive black hole, and the spectro-photometric model covers a wide range of stellar ages...

  18. Chemical agents and the immune response.

    OpenAIRE

    Luster, M I; Rosenthal, G J

    1993-01-01

    Our desire to understand the potential adverse human health effects of environmental chemical exposure has coincided with an increased understanding of the immune system and an appreciation of its complex regulatory network. This has spawned a broad interest in the area of immunotoxicology within the scientific community as well as certain concerns in the public sector regarding chemical-induced hypersensitivity and immunosuppression. The incidence of alleged human sensitization to chemicals ...

  19. Regulating Chemicals: A Public Policy Challenge

    OpenAIRE

    Archibald, Sandra O.

    1990-01-01

    Policy and regulatory decisions about the use of chemicals in food production and processing are unavoidable. However, scientific and economic information upon which to base these decisions is limited. At the same time many people have stakes in the benefits or costs associated with the use of these chemicals. Consumers are increasingly concerned that current regulations do not emphasize health risks sufficiently and give too much emphasis to current economic benefits from chemicals. Producer...

  20. Thermal Denaturation of Proteins and Chemical Equilibrium

    OpenAIRE

    Moroni, Laura; Gellini, Cristina; Remigio Salvi, Pier

    2015-01-01

    The thermal denaturation of proteins is considered as a process by means of which chemical equilibrium can be introduced to undergraduate students of Chemistry related curricula. In this approach chemical potential μ, Gibbs energy G, degree of advancement ξ and Le Châtelier principle are integrated with chemical equilibrium. With reference to α-Chymotrypsinogen A as a test case, the process is discussed in terms of a simplified two-state model. The activity is addressed to physical chemistry ...

  1. Ecological optimization of endoreversible chemical engines

    OpenAIRE

    Dan Xia, Lingen Chen, Fengrui Sun

    2011-01-01

    Optimal ecological performances of endoreversible chemical engine cycles with both linear and diffusive mass transfer laws are derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the power output and entropy production rate of the chemical engines. Numerical examples are given to show the effects of mass-reservoir chemical potential ratio and mass-transfer coefficient ratio on the ecological ...

  2. Chemical Mechanism Solvers in Air Quality Models

    OpenAIRE

    Linford, John C.; Adrian Sandu; Rolf Sander; Hong Zhang

    2011-01-01

    The solution of chemical kinetics is one of the most computationally intensive tasks in atmospheric chemical transport simulations. Due to the stiff nature of the system, implicit time stepping algorithms which repeatedly solve linear systems of equations are necessary. This paper reviews the issues and challenges associated with the construction of efficient chemical solvers, discusses several families of algorithms, presents strategies for increasing computational efficiency, and gives insi...

  3. Smart Chemical Sensors: Concepts and Application

    OpenAIRE

    Udina Oliva, Sergi

    2012-01-01

    This PhD thesis introduces basic concepts of smart chemical sensors design, which are afterwards applied to a particular application: the analysis of natural gas. The thesis addresses thus two sets of objective, a first set of objectives related to the conceptual design of a smart chemical sensor using smart sensor standards: - The design of an optimal smart chemical sensor architecture - The novel combination in a working prototype of the highly complementary smart sensor stan...

  4. Surface chemical studies of chemical vapour deposited diamond thin films

    International Nuclear Information System (INIS)

    Polycrystalime diamond grown by low pressure chemical vapour deposition (CVD) techniques has emerged in recent years as a new material with applications in such areas as optics, electronics, radiation detectors, chemical sensors and electrochemistry. A main aim of this thesis has been to advance current knowledge of the surface chemical properties of CVD diamond to underpin the development of our understanding of the properties and potential applications of this material. Cl2 is found to adsorb dissociatively on the clean, hydrogen-free diamond surface up to sub-monolayer coverage with a sticking probability of ∼1.2x10-3. Adsorption is a non-activated process, and the sticking probability and extent of coverage decreased with increasing temperature. This was shown to contrast with the behaviour found for the interaction of chlorine with the hydrogenated diamond surface where increased sticking probabilities and saturation surface coverages were observed, and where the reactivity also increased with temperature. Thermal desorption of atomic Cl occurred over a broad temperature range m both chemisorption systems, indicating the presence of more than one binding state. Atomic hydrogen was successful in efficiently etching the bound Cl from the surface. XeF2 was found to adsorb dissociatively onto the clean diamond surface to give up to monolayer coverages of F, which formed two distinct binding states. The first state, populated at low coverage, was predominantly covalent in character, while the second state, occurring at high surface coverages, had more ionic bonding character. Pre-hydrogenation of the diamond surface increased the reactive sticking probability observed, but decreased the extent of coverage by blocking reactive sites. The semi-ionic F was readily etched by atomic hydrogen, and underwent thermal desorption at temperatures as low as 300 deg C. The covalent form was more stable, being seemingly resistant to etching and persistent to high temperatures

  5. Arrays of coupled chemical oscillators

    Science.gov (United States)

    Forrester, Derek Michael

    2015-11-01

    Oscillating chemical reactions result from complex periodic changes in the concentration of the reactants. In spatially ordered ensembles of candle flame oscillators the fluctuations in the ratio of oxygen atoms with respect to that of carbon, hydrogen and nitrogen produces an oscillation in the visible part of the flame related to the energy released per unit mass of oxygen. Thus, the products of the reaction vary in concentration as a function of time, giving rise to an oscillation in the amount of soot and radiative emission. Synchronisation of interacting dynamical sub-systems occurs as arrays of flames that act as master and slave oscillators, with groups of candles numbering greater than two, creating a synchronised motion in three-dimensions. In a ring of candles the visible parts of each flame move together, up and down and back and forth, in a manner that appears like a “worship”. Here this effect is shown for rings of flames which collectively empower a central flame to pulse to greater heights. In contrast, situations where the central flames are suppressed are also found. The phenomena leads to in-phase synchronised states emerging between periods of anti-phase synchronisation for arrays with different columnar sizes of candle and positioning.

  6. Arrays of coupled chemical oscillators

    CERN Document Server

    Forrester, Derek Michael

    2016-01-01

    Oscillating chemical reactions result from complex periodic changes in the concentration of the reactants. In spatially ordered ensembles of candle flame oscillators the fluctuations in the ratio of oxygen atoms with respect to that of carbon, hydrogen and nitrogen produces an oscillation in the visible part of the flame related to the energy released per unit mass of oxygen. Thus, the products of the reaction vary in concentration as a function of time, giving rise to an oscillation in the amount of soot and radiative emission. Synchronisation of interacting dynamical sub-systems occurs as arrays of flames that act as master and slave oscillators, with groups of candles numbering greater than two, creating a synchronised motion in three-dimensions. In a ring of candles the visible parts of each flame move together, up and down and back and forth, in a manner that appears like a "worship". Here this effect is shown for rings of flames which collectively empower a central flame to pulse to greater heights. In ...

  7. The chemical physics of surfaces

    CERN Document Server

    Morrison, Stanley Roy

    1990-01-01

    Even more importantly, some authors who have contributed substantially to an area may have been overlooked. For this I apologize. I have, however, not attempted to trace techniques or observa­ tions historically, so there is no implication (unless specified) that the authors referred to were or were not the originators of a given method or observation. I would like to acknowledge discussions with co-workers at SFU for input relative to their specialties, to acknowledge the help of students who have pointed out errors and difficulties in the earlier presentation, and to acknowledge the infinite patience of my wife Phyllis while I spent my sabbatical and more in libraries and punching computers. S. Roy Morrison 0 1 Contents Notation XV 1. Introduction 1 1. 1. Surface States and Surface Sites . 1 1. 1. 1. The Chemical versus Electronic Representation of the Surface. 1 1. 1. 2. The Surface State on the Band Diagram 4 1. 1. 3. The Fermi Energy in the Surface State Model. 6 1. 1. 4. Need for Both Surface...

  8. [Chemical constituents from Cinnamomum cassia].

    Science.gov (United States)

    He, Shan; Jiang, Yong; Tu, Peng-fei

    2015-09-01

    Various column chromatography, such as silica gel, Sephadex LH-20, ODS, and semi-preparative HPLC was used to isolate and purify the chemical constituents from Cinnamomum cassia. The structures were determined on the basis of NMR and MS spectral data analysis, together with the comparison with literature data. Fifteen compounds were isolated from the 85% aqueous ethanol extract of C. cassia, and their structures were identified as (2R, 3R)-5,7,3',4'-tetramethoxyflavan-3-ol( 1), (2R, 3R)-5,7-dimethoxy-3',4'-methylenedioxyflavan-3-ol (2), coumarin (3), cinnamic acid (4), (E)-2-hydroxy-phenylpropionic acid cinnamoyl ester (5), 3, 3', 4, 4'-tetrahydroxy biphenyl (6), methylstictic acid (7), epi-boscialin (8), (1R,2S,3S,4S)-2,3-epoxy-1, 4-dihydroxy-5-methyl-5-cyelohexene (9), 4,5-dihydroxy-3-methyl cyclohex-2-enone (10), cis-4-hydroxymellein (11), and 2-hydroxy-4-methoxyl-cinnamaldehyde (12). Compounds 5-11 were obtained from this genus plants for the first time. PMID:26983207

  9. The Chemical Evolution of Helium

    CERN Document Server

    Balser, D S

    2006-01-01

    We report on measurements of the 4He abundance toward the outer Galaxy HII region S206 with the NRAO Green Bank telescope. Observations of hydrogen and helium radio recombination lines between 8-10 GHz were made toward the peak radio continuum position in S206. We derive 4He/H = 0.08459 +/- 0.00088 (random) +/- 0.0010 (known systematic), 20% lower than optical recombination line results. It is difficult to reconcile the large discrepancy between the optical and radio values even when accounting for temperature, density, and ionization structure or for optical extinction by dust. Using only M17 and S206 we determine dY/dZ = 1.41 +/- 0.62 in the Galaxy, consistent with standard chemical evolution models. High helium abundances in the old stellar population of elliptical galaxies can help explain the increase in UV emission with shorter wavelength between 2000 and 1200 Angstrom, called the UV-upturn or UVX. Our lower values of dY/dZ are consistent with a normal helium abundance at higher metallicity and suggest ...

  10. Origin of Cosmic Chemical Abundances

    CERN Document Server

    Maio, Umberto

    2015-01-01

    Cosmological N-body hydrodynamic computations following atomic and molecular chemistry (e$^-$, H, H$^+$, H$^-$, He, He$^+$, He$^{++}$, D, D$^+$, H$_2$, H$_2^+$, HD, HeH$^+$), gas cooling, star formation and production of heavy elements (C, N, O, Ne, Mg, Si, S, Ca, Fe, etc.) from stars covering a range of mass and metallicity are used to explore the origin of several chemical abundance patterns and to study both the metal and molecular content during simulated galaxy assembly. The resulting trends show a remarkable similarity to up-to-date observations of the most metal-poor damped Lyman-$\\alpha$ absorbers at redshift $z\\gtrsim 2$. These exhibit a transient nature and represent collapsing gaseous structures captured while cooling is becoming effective in lowering the temperature below $\\sim 10^4\\,\\rm K$, before they are disrupted by episodes of star formation or tidal effects. Our theoretical results agree with the available data for typical elemental ratios, such as [C/O], [Si/Fe], [O/Fe], [Si/O], [Fe/H], [O/...

  11. Recontamination following dilute chemical decontamination

    International Nuclear Information System (INIS)

    Decontamination is beneficial in reducing radiation fields before inspection, maintenance, or repair work has to be performed on reactor systems. If the fields remain low at subsequent shutdowns, further benefit is attributable to the decontamination. Conversely, if fields rapidly become as high as before the decontamination, no residual benefit derives. In the case where the field rapidly becomes higher than before the decontamination, a detriment from the decontamination is experienced at subsequent shutdowns. In this paper the recontamination data following six separate dilute chemical decontaminations are reported for surveillance periods of up to two years. Surfaces operating at low temperature hardly recontaminated at all over the two-year period; surfaces exposed to high temperatures recontaminated to about 95% of their predecontamination level over a two-year period. A rapid recontamination rate for about three months following the decontamination was followed by recontamination at a rate which is significantly below the published rates for most BWRs in the USA, and for these two plants in particular. In all six cases studied, residual benefit from the decontamination was experienced at subsequent shutdowns. (author)

  12. [Chemical constituents from Euphorbia lunulata].

    Science.gov (United States)

    Zhao, Ming; Wu, Shuang; Li, Jun; Tang, Wan-Xia; Wang, Jin-Lan; Zhang, Shu-Jun

    2014-06-01

    The chemical constituents from Euphorbia lunulata was investigated in this paper. Fourteen compounds were isolated and purified by column chromatographies on silica gel and preparative HPLC. Their structures were identified by physiochemical properties and NMR data analysis as lupeol (1), euphol (2), cassipourol(3) , 24-methylenecycloartan-3beta-ol (4), 24-hydroperoxycycloart-25-en-3beta-ol (5), 25-hydroperoxycycloart-23-en-3beta-ol (6), betulin (7), uvaol (8), (23E) -25-methoxycycloart-23-en-3beta-ol (9), (23E) -cycloart-23,25-dien-3beta-ol (10), 24-methylenecycloartan-3beta, 28-diol (11), salicinolide (12), 2alpha, 3beta, 5alpha, 9alpha, 15beta-pentaacetoxy-11,12-epoxy-7beta, 8alpha-diisobutyryloxyjatropha-6 (17) -en-14-one (13) and 3beta, 5alpha, 15beta-triacetoxy-7beta-isobutyryloxy-9alpha-nicotinoyloxyjatropha-6 (17), 11(E)-dien-14-one (14). Among them, compounds 1-11 were isolated from E. lunulata for the first time. PMID:25244761

  13. Inorganic chemically active adsorbents (ICAAs)

    Energy Technology Data Exchange (ETDEWEB)

    Ally, M.R. [Oak Ridge National Lab., TN (United States); Tavlarides, L.

    1997-10-01

    Oak Ridge National Laboratory (ORNL) researchers are developing a technology that combines metal chelation extraction technology and synthesis chemistry. They begin with a ceramic substrate such as alumina, titanium oxide or silica gel because they provide high surface area, high mechanical strength, and radiolytic stability. One preparation method involves silylation to hydrophobize the surface, followed by chemisorption of a suitable chelation agent using vapor deposition. Another route attaches newly designed chelating agents through covalent bonding by the use of coupling agents. These approaches provide stable and selective, inorganic chemically active adsorbents (ICAAs) tailored for removal of metals. The technology has the following advantages over ion exchange: (1) higher mechanical strength, (2) higher resistance to radiation fields, (3) higher selectivity for the desired metal ion, (4) no cation exchange, (5) reduced or no interference from accompanying anions, (6) faster kinetics, and (7) easy and selective regeneration. Target waste streams include metal-containing groundwater/process wastewater at ORNL`s Y-12 Plant (multiple metals), Savannah River Site (SRS), Rocky Flats (multiple metals), and Hanford; aqueous mixed wastes at Idaho National Engineering Laboratory (INEL); and scrubber water generated at SRS and INEL. Focus Areas that will benefit from this research include Mixed Waste, and Subsurface Contaminants.

  14. Chemical Modeling of Cometary Anions

    Science.gov (United States)

    Cordiner, Martin; Charnley, S. B.

    2009-09-01

    The presence of negative ions (anions) in cometary comae is known from Giotto mass spectrometry of 1P/Halley. The anions O-, OH-, C-, CH- and CN- have been detected, as well as unidentified anions with masses 22-65 and 85-110 amu (Chaizy et al. 1991). Organic molecular anions are known to have a significant impact on the charge balance of interstellar clouds and circumstellar envelopes and have been shown to act as catalysts for the gas-phase synthesis of larger hydrocarbon molecules in the ISM, but their importance in cometary comae has not previously been explored. We present details of the first attempt to model the chemistry of anions in cometary comae. Based on the combined chemical and hydrodynamical model of Rodgers & Charnley (2002), we investigate the role of the hydrocarbon and nitrile anions Cn-, CnH- and CnN- in the coma. We calculate the effects of these anions on the charge balance and examine their impact on cometary coma chemistry. References: Chaizy, P. et al. 1991, Nature, 349, 393 Rodgers, S.D. & Charnley, S.B. 2002, MNRAS, 330, 660

  15. Chemical leucoderma: Indian scenario, prognosis, and treatment

    Directory of Open Access Journals (Sweden)

    Bajaj A

    2010-01-01

    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 come down. In the recent past various chemicals in consumer products have also been documented to produce depigmentation.In India due to lax quality control measures chemical leucoderma due to consumer items is not uncommon.The various consumer items documented to cause contact depigmentation are sticker bindis,rain shoes,plastic chappals,hair dye/ black henna( kali mehndi, alta, wallets and even mobile plastic covers.

  16. Multiple chemical sensitivity, en veldefineret lidelse?

    DEFF Research Database (Denmark)

    Kolstad, Henrik A; Silberschmidt, Martin; Nielsen, Jesper Bo;

    2006-01-01

    Some people react to smells or chemicals at levels far below toxicological thresholds with nonspecific symptoms, fear and social isolation. They may be diagnosed with multiple chemical sensitivity. There is no empirical evidence indicating that this condition is explained by toxicological...... mechanisms, even though a number of theories have been proposed. The authors of this review conclude that this is a functional condition. These patients need information and treatment in accordance with this fact. Instead of being advised how to avoid exposure to chemicals, they should be properly trained in...... appropriate confrontation with the chemicals encountered in everyday life....

  17. Multiple chemical sensitivity, en veldefineret lidelse?

    DEFF Research Database (Denmark)

    Kolstad, Henrik A.; Silberschmidt, Martin; Nielsen, Jesper Bo;

    2006-01-01

    Some peope react to smells or chemicals at levels far below toxicological thresholds with nonspecific symptoms, fear and social isolation. They may be diagnosed with multiple chemical sensitivity. There is no empirical evidence indicating that this condition is explained by toxicological mechanisms......, even though a number of theories have been proposed. The authors of this review conclude that this is a functional condition. These patients need information and treatment in accordance with this fact. Instead of being advised how to avoid exposure to chemicals, they should be properly trained in...... appropriate confrontation with the chemicals encountered in everyday life....

  18. Hazardous chemical tracking system (HAZ-TRAC)

    Energy Technology Data Exchange (ETDEWEB)

    Bramlette, J D; Ewart, S M; Jones, C E

    1990-07-01

    Westinghouse Idaho Nuclear Company, Inc. (WINCO) developed and implemented a computerized hazardous chemical tracking system, referred to as Haz-Trac, for use at the Idaho Chemical Processing Plant (ICPP). Haz-Trac is designed to provide a means to improve the accuracy and reliability of chemical information, which enhances the overall quality and safety of ICPP operations. The system tracks all chemicals and chemical components from the time they enter the ICPP until the chemical changes form, is used, or becomes a waste. The system runs on a Hewlett-Packard (HP) 3000 Series 70 computer. The system is written in COBOL and uses VIEW/3000, TurboIMAGE/DBMS 3000, OMNIDEX, and SPEEDWARE. The HP 3000 may be accessed throughout the ICPP, and from remote locations, using data communication lines. Haz-Trac went into production in October, 1989. Currently, over 1910 chemicals and chemical components are tracked on the system. More than 2500 personnel hours were saved during the first six months of operation. Cost savings have been realized by reducing the time needed to collect and compile reporting information, identifying and disposing of unneeded chemicals, and eliminating duplicate inventories. Haz-Trac maintains information required by the Superfund Amendment Reauthorization Act (SARA), the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the Occupational Safety and Health Administration (OSHA).

  19. Board on chemical sciences and technology

    International Nuclear Information System (INIS)

    The Board on Chemical Sciences and Technology organizes and provides direction for standing and ad-hoc committees charged with addressing specific issues relevant to the continued health of the chemical sciences and technology community. Studies currently under the oversight of the BCST include a major survey of the chemical sciences, a complementary survey of chemical engineering, an examination of the problems of biohazards in the laboratory, and an analysis of the roots and magnitude of the problem of obsolescent facilities for research and teaching in departments in the chemical sciences and engineering. The Board continues to respond to specific agency requests for program assessments and advice. BCST members are designated to serve as liaison with major federal agencies or departments that support research in order to help identify ways for the Board to assist these organizations. The BCST maintains close contact with professional societies and non-governmental organizations that share the Board's concern for the health of chemical sciences and technology. Individual Board members are assigned responsibility for liaison with the American Chemical Society, the American Institute of Chemical Engineers, the American Society of Biological Chemists, the Council for Chemical Research, the NAS Chemistry and Biochemistry Sections, and the National Academy of Engineering. In the past few years, the Board has served as a focus and a forum for a variety of issues that relate specifically to the health of chemistry

  20. Can chemical structure predict reproductive toxicity?

    OpenAIRE

    Maslankiewicz L; Hulzebos EM; Vermeire TG; Muller JJA; Piersma AH; SEC

    2005-01-01

    Structure-Activity Relationships (SARs), including Quantitative SARs, are applied to the hazard assessment of chemicals. This need is all the more urgent considering the proposed new EU policy on chemicals in REACH, which stresses the need for non-animal testing. DEREKfW and the TSCA Chemical Category List of the New Chemicals Program of the US-EPA were chosen to predict reproductive toxicity for REACH purposes. DEREKfW is a software program predicting the toxicological properties using the l...

  1. Chemical Engineering Education - Current and Future Trends

    OpenAIRE

    Gani, Rafiqul

    2011-01-01

    The chemical industry today is changed from the chemical industry of twenty-five years ago. Clear evidence of this change comes from the jobs taken by graduating chemical professionals in North America, Europe, and some of the Asian countries. Twenty-five years ago, eighty percent of these graduating students went to the commodity chemical industry, exemplified by Dupont, Exxon, Shell, ICI, BASF and Dow, to name a few. Now, twenty percent do. Twenty-five years ago, around ten percent went to ...

  2. Overall View of Chemical and Biochemical Weapons

    Directory of Open Access Journals (Sweden)

    Vladimír Pitschmann

    2014-06-01

    Full Text Available This article describes a brief history of chemical warfare, which culminated in the signing of the Chemical Weapons Convention. It describes the current level of chemical weapons and the risk of using them. Furthermore, some traditional technology for the development of chemical weapons, such as increasing toxicity, methods of overcoming chemical protection, research on natural toxins or the introduction of binary technology, has been described. In accordance with many parameters, chemical weapons based on traditional technologies have achieved the limit of their development. There is, however, a big potential of their further development based on the most recent knowledge of modern scientific and technical disciplines, particularly at the boundary of chemistry and biology. The risk is even higher due to the fact that already, today, there is a general acceptance of the development of non-lethal chemical weapons at a technologically higher level. In the future, the chemical arsenal will be based on the accumulation of important information from the fields of chemical, biological and toxin weapons. Data banks obtained in this way will be hardly accessible and the risk of their materialization will persist.

  3. Chemical Implementation of Finite-State Machines

    Science.gov (United States)

    Hjelmfelt, Allen; Weinberger, Edward D.; Ross, John

    1992-01-01

    With methods developed in a prior article on the chemical kinetic implementation of a McCulloch-Pitts neuron, connections among neurons, logic gates, and a clocking mechanism, we construct examples of clocked finite-state machines. These machines include a binary decoder, a binary adder, and a stack memory. An example of the operation of the binary adder is given, and the chemical concentrations corresponding to the state of each chemical neuron are followed in time. Using these methods, we can, in principle, construct a universal Turing machine, and these chemical networks inherit the halting problem

  4. Plasma-chemical processes and systems

    International Nuclear Information System (INIS)

    The direct applications of plasma technology on chemistry and metallurgy are presented. The physical fundaments of chemically active non-equilibrium plasma, the reaction kinetics, and the physical chemical transformations occuring in the electrical discharges, which are applied in the industry, are analysed. Some plasma chemical systems and processes related to the energy of hydrogen, with the chemical technology and with the metallurgy are described. Emphasis is given to the optimization of the energy effectiveness of these processes to obtain reducers and artificial energetic carriers. (M.C.K.)

  5. Chemical Carcinogenesis Research Information System (CCRIS)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The CCRIS database contains chemical records with carcinogenicity, mutagenicity, tumor promotion, and tumor inhibition test results. CCRIS provides historical...

  6. Xingfa Group: To Be World-Famous Phosphorus Chemical Enterprise

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ As the biggest fine phosphorus chemical producer in China, Hubei Xingfa Chemicals Co., Ltd. (Xingfa Group, SH: 600141) is mainly engaged in the production and sales of phosphorus chemicals and fine chemicals.

  7. Potential Impacts of Spilled Hydraulic Fracturing Fluid Chemicals on Water Resources: Types, volumes, and physical-chemical properties of chemicals

    Science.gov (United States)

    Hydraulic fracturing (HF) fluid chemicals spilled on-site may impact drinking water resources. While chemicals generally make up <2% of the total injected fluid composition by mass, spills may have undiluted concentrations. HF fluids typically consist of a mixture of base flui...

  8. Chemical Sensing for Buried Landmines - Fundamental Processes Influencing Trace Chemical Detection

    Energy Technology Data Exchange (ETDEWEB)

    PHELAN, JAMES M.

    2002-05-01

    Mine detection dogs have a demonstrated capability to locate hidden objects by trace chemical detection. Because of this capability, demining activities frequently employ mine detection dogs to locate individual buried landmines or for area reduction. The conditions appropriate for use of mine detection dogs are only beginning to emerge through diligent research that combines dog selection/training, the environmental conditions that impact landmine signature chemical vapors, and vapor sensing performance capability and reliability. This report seeks to address the fundamental soil-chemical interactions, driven by local weather history, that influence the availability of chemical for trace chemical detection. The processes evaluated include: landmine chemical emissions to the soil, chemical distribution in soils, chemical degradation in soils, and weather and chemical transport in soils. Simulation modeling is presented as a method to evaluate the complex interdependencies among these various processes and to establish conditions appropriate for trace chemical detection. Results from chemical analyses on soil samples obtained adjacent to landmines are presented and demonstrate the ultra-trace nature of these residues. Lastly, initial measurements of the vapor sensing performance of mine detection dogs demonstrates the extreme sensitivity of dogs in sensing landmine signature chemicals; however, reliability at these ultra-trace vapor concentrations still needs to be determined. Through this compilation, additional work is suggested that will fill in data gaps to improve the utility of trace chemical detection.

  9. Exploring the planetary boundary for chemical pollution.

    Science.gov (United States)

    Diamond, Miriam L; de Wit, Cynthia A; Molander, Sverker; Scheringer, Martin; Backhaus, Thomas; Lohmann, Rainer; Arvidsson, Rickard; Bergman, Åke; Hauschild, Michael; Holoubek, Ivan; Persson, Linn; Suzuki, Noriyuki; Vighi, Marco; Zetzsch, Cornelius

    2015-05-01

    Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if "unacceptable global change" is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step forward, at this point single or multiple PBCPs are challenging to operationalize due to the extremely large number of commercial chemicals or mixtures of chemicals that cause myriad adverse effects to innumerable species and ecosystems, and the complex linkages between emissions, environmental concentrations, exposures and adverse effects. As well, the normative nature of a PBCP presents challenges of negotiating pollution limits amongst societal groups with differing viewpoints. Thus, a combination of approaches is recommended as follows: develop indicators of chemical pollution, for both control and response variables, that will aid in quantifying a PBCP(s) and gauging progress towards reducing chemical pollution; develop new technologies and technical and social

  10. Chemical compatibility screening test results

    International Nuclear Information System (INIS)

    A program for evaluating packaging components that may be used in transporting mixed-waste forms has been developed and the first phase has been completed. This effort involved the screening of ten plastic materials in four simulant mixed-waste types. These plastics were butadiene-acrylonitrile copolymer rubber, cross-linked polyethylene (XLPE), epichlorohydrin rubber, ethylene-propylene rubber (EPDM), fluorocarbon (Viton or Kel-F), polytetrafluoroethylene, high-density polyethylene (HDPE), isobutylene-isoprene copolymer rubber (butyl), polypropylene, and styrene-butadiene rubber (SBR). The selected simulant mixed wastes were (1) an aqueous alkaline mixture of sodium nitrate and sodium nitrite; (2) a chlorinated hydrocarbon mixture; (3) a simulant liquid scintillation fluid; and (4) a mixture of ketones. The testing protocol involved exposing the respective materials to 286,000 rads of gamma radiation followed by 14-day exposures to the waste types at 60 degrees C. The seal materials were tested using vapor transport rate (VTR) measurements while the liner materials were tested using specific gravity as a metric. For these tests, a screening criterion of 0.9 g/hr/m2 for VTR and a specific gravity change of 10% was used. Based on this work, it was concluded that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In the chlorinated hydrocarbon simulant mixed waste, only Viton passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture simulant mixed waste, none of the seal materials met the screening criteria. For specific gravity testing of liner materials, the data showed that while all materials with the exception of polypropylene passed the screening criteria, Kel-F, HDPE, and XLPE offered the greatest resistance to the combination of radiation and chemicals

  11. 46 CFR 154.1150 - Distribution of dry chemical.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Distribution of dry chemical. 154.1150 Section 154.1150... Firefighting System: Dry Chemical § 154.1150 Distribution of dry chemical. (a) All locations on the above deck... chemical hand hose lines; or (2) At least one dry chemical hand hose line and one dry chemical monitor....

  12. Cost effectiveness of dilute chemical decontamination

    International Nuclear Information System (INIS)

    The basic principles of dilute chemical decontamination are described, as well as the method of application. Methods of computing savings in radiation dose and costs are presented, with results from actual experience and illustrative examples. It is concluded that dilute chemical decontamination is beneficial in many cases. It reduces radiation exposure of workers, saves money, and simplifies maintenance work

  13. Chemical Safety Vulnerability Working Group Report

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    This report marks the culmination of a 4-month review conducted to identify chemical safety vulnerabilities existing at DOE facilities. This review is an integral part of DOE's efforts to raise its commitment to chemical safety to the same level as that for nuclear safety.

  14. Career Opportunities in Chemistry and Chemical Engineering.

    Science.gov (United States)

    Glover, Trienne

    This pamphlet discusses career and employment opportunities in chemical engineering. Necessary college preparation is described and median salaries by degree are tabulated. Nontraditional careers in chemistry are also described. Future demand for chemists and chemical engineers is projected to 1985 and the availability of jobs for women and…

  15. Assessing ecorelevance of emerging chemicals in sediments

    DEFF Research Database (Denmark)

    Forbes, Valery E.; Selck, Henriette; Salvito, D.

    2007-01-01

    Environmental monitoring of the Great Lakes and elsewhere has detected the presence of a wide variety of chemicals which has raised concern that these chemicals pose risks to resident species. Sediments are of particular interest due to their tendency to accumulate hydrophobic and persistent chem...

  16. Chemical Biodynamics Division. Annual report 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

    The Chemical Biodynamics Division of LBL continues to conduct basic research on the dynamics of living cells and on the interaction of radiant energy with organic matter. Many aspects of this basic research are related to problems of environmental and health effects of fossil fuel combustion, solar energy conversion and chemical/ viral carcinogenesis.

  17. Chemical Dependence and Clinical Depression in Pregnancy.

    Science.gov (United States)

    Burns, Kayreen; And Others

    1985-01-01

    Assessed the extent and depth of depression in 54 chemically dependent pregnant women, divided into three groups by age. Results indicated that the older chemically dependent women scored significantly higher on the depression index than did either of the two younger groups, while the teenagers obtained a mean score comparable to that of the…

  18. The modern alchemy: The chemical industry

    International Nuclear Information System (INIS)

    A brief history is presented on the development of chemistry from the antiquity, through alchemy, iatrochemistry, electrochemistry, atomic theory and the XVII, XVIII, XIX and X X centuries discoveries up to modern chemistry, fine chemistry, chemical engineering and the modern chemical industry with all of its consequences

  19. Chemical labeling of electrochemically cleaved peptides

    NARCIS (Netherlands)

    Roeser, Julien; Alting, Niels F. A.; Permentier, Hjalmar P.; Bruins, Andries P.; Bischoff, Rainer P. H.

    2013-01-01

    RATIONALE Cleavage of peptide bonds C-terminal to tyrosine and tryptophan after electrochemical oxidation may become a complementary approach to chemical and enzymatic cleavage. A chemical labeling approach specifically targeting reactive cleavage products is presented here and constitutes a promisi

  20. Standardized chemical synthesis of Pseudomonas aeruginosa pyocyanin

    Directory of Open Access Journals (Sweden)

    Rajkumar Cheluvappa

    2014-01-01

    As we have extracted pyocyanin both from P. aeruginosa cultures, and via chemical synthesis; we know the procedural and product-quality differences. We endorse the relative ease, safety, and convenience of using the chemical synthesis described here. Crucially, our “naturally endotoxin-free” pyocyanin can be extracted easily without using infectious bacteria.

  1. The potential for chemical evolution on Titan

    Science.gov (United States)

    Beauchamp, P. M.; Lunine, J. I.; Welch, C.

    2002-01-01

    Sampling of organics to determine oxygen content, extent of acetylene polymerization, existence of chiral molecules and enantiomeric excesses, and searches for specific polymer products, would be of interest in assessing how organic chemistry evolves toward biochemistry. Such efforts would require fairly sophisticated chemical analyses from landed missions. This paper examines this chemistry and the potential instruments that could distinguish chemical evolution.

  2. The chemical evolution of the solar neighbourhood

    OpenAIRE

    Vanbeveren, D.; De Donder, E.

    2002-01-01

    Recent models of galactic chemical evolution account for updated evolutionary models of massive stars (with special emphasis on stellar winds) and for the effects of intermediate mass and massive binaries. The results are summarised. We also present a critical discussion on possible effects of stellar rotation on overall galactic chemical evolutionary simulations.

  3. 3F: A Leading Fluorine Chemical Company

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Shanghai 3F New Materials Co., Ltd.(3F, SH: 600636) is a company mainlyengaged in the research, development,production and operation of fluorine-containing materials. It owns a complete fluorine chemical industrial chain.Products include CFCs, CFC substitutes,fluorine-containing polymers and fluo-rine-containing fine chemicals.

  4. 7. Eurasia Conference on Chemical Sciences (abstracts)

    International Nuclear Information System (INIS)

    The 7th Eurasia Conference on Chemical sciences (EuAs/sub 2/S-7) was held from 8-12 March, 2002 at Karachi, Pakistan. Scientists from thirty different countries had participated in this conference. Several topics from chemical world were highlighted in this conference including use of radioisotopes in different fields and specially environment which have been included here. (A.B)

  5. Research on the chemical speciation of actinides

    International Nuclear Information System (INIS)

    A demand for the safe and effective management of spent nuclear fuel and radioactive waste generated from nuclear power plant draws increasing attention with the growth of nuclear power industry. The objective of this project is to establish the basis of research on the actinide chemistry by using advanced laser-based highly sensitive spectroscopic systems. Researches on the chemical speciation of actinides are prerequisite for the development of technologies related to nuclear fuel cycles, especially, such as the safe management of high level radioactive wastes and the chemical examination of irradiated nuclear fuels. For supporting these technologies, laser-based spectroscopies have been performed for the chemical speciation of actinide in an aqueous solutions and the quantitative analysis of actinide isotopes in spent nuclear fuels. In this report, results on the following subjects have been summarized. (1) Development of TRLFS technology for chemical speciation of actinides, (2) Development of LIBD technology for measuring solubility of actinides, (3) Chemical speciation of plutonium complexes by using a LWCC system, (4) Development of LIBS technology for the quantitative analysis of actinides, (5) Development of technology for the chemical speciation of actinides by CE, (6) Evaluation on the chemical reactions between actinides and humic substances, (7) Chemical speciation of actinides adsorbed on metal oxides surfaces, (8) Determination of actinide source terms of spent nuclear fuel

  6. Solar technology applications in chemical waste management

    International Nuclear Information System (INIS)

    Using solar energy to destroy waste chemicals and toxic materials has great appeal to environmentalists, industrialists and the public. Using free sunlight to resolve one of the industrial age's most troublesome problems is destruction must demonstrate that it competes favorably with current approaches in economic and environmental areas. This paper provides an environmental and economic analysis of solar applications in chemical waste management

  7. Beyond petrochemicals: The renewable chemicals industry

    DEFF Research Database (Denmark)

    Vennestrøm, P.N.R.; Osmundsen, Christian Mårup; Christensen, C.H.;

    2011-01-01

    From petroleum to bioleum: Since biomass is a limited resource, it is necessary to consider its best use. The production of select chemicals from biomass, rather than its use as fuel, could effectively replace the use of petroleum in the chemical industry, but the inherent functionality of biomass...

  8. Quantum chemical studies of estrogenic compounds

    Science.gov (United States)

    Quantum chemical methods are potent tools to provide information on the chemical structure and electronic properties of organic molecules. Modern computational chemistry methods have provided a great deal of insight into the binding of estrogenic compounds to estrogenic receptors (ER), an important ...

  9. CYTOKINE PROFILING FOR CHEMICAL RESPIRATORY SENSITIZERS

    Science.gov (United States)

    CYTOKINE PROFILING FOR CHEMICAL RESPIRATORY SENSITIZERS. LM Plitnick1, SE Loveless2, GS Ladics2, MP Holsapple3, MJ Selgrade4, DM Sailstad4 & RJ Smialowicz4. 1UNC, Chapel Hill, NC; 2DuPont Co., Haskell Laboratory, Newark, DE; 3Dow Chemical, Midland, MI & 4USEPA, NHEERL, RTP, NC.

  10. Graphene composites containing chemically bonded metal oxides

    Indian Academy of Sciences (India)

    K Pramoda; S Suresh; H S S Ramakrishna Matte; A Govindaraj

    2013-08-01

    Composites of graphene involving chemically bonded nano films of metal oxides have been prepared by reacting graphene containing surface oxygen functionalities with metal halide vapours followed by exposure to water vapour. The composites have been characterized by electron microscopy, atomic force microscopy and other techniques. Magnetite particles chemically bonded to graphene dispersible in various solvents have been prepared and they exhibit fairly high magnetization.

  11. The Restorative Recovery School: Countering Chemical Dependency

    Science.gov (United States)

    Riestenberg, Nancy

    2007-01-01

    In a recovery school, the students commit to working on recovery from chemical dependency and addiction while becoming successful students. Since all of the students attending the school have been in chemical dependency treatment, the safety of the environment is the first concern of students, their families and staff. Applying restorative…

  12. Innovations Help Chemical Makers Improve Growing Potential

    Institute of Scientific and Technical Information of China (English)

    Zhong Weike

    2007-01-01

    @@ With overheated construction all over the country, China's GDP continued its fast growth in the first half. After suffering an explosion at a Jilin aniline facility, another explosion at Cangzhou TDI and a big outbreak of water pollution at Wuxi, the chemical raw materials and chemical manufacturing sectors are getting strict supervision from the central government.

  13. Heat Exchanger Lab for Chemical Engineering Undergraduates

    Science.gov (United States)

    Rajala, Jonathan W.; Evans, Edward A.; Chase, George G.

    2015-01-01

    Third year chemical engineering undergraduate students at The University of Akron designed and fabricated a heat exchanger for a stirred tank as part of a Chemical Engineering Laboratory course. The heat exchanger portion of this course was three weeks of the fifteen week long semester. Students applied concepts of scale-up and dimensional…

  14. Operating Modes Of Chemical Reactors Of Polymerization

    OpenAIRE

    Meruyert Berdieva; Aiman Ospanova; Madina Koshkinbayeva; Tamara Zhukabayeva

    2012-01-01

    In the work the issues of stable technological modes of operation of main devices of producing polysterol reactors have been researched as well as modes of stable operation of a chemical reactor have been presented, which enables to create optimum mode parameters of polymerization process, to prevent emergency situations of chemical reactor operation in industrial conditions.

  15. Operating Modes Of Chemical Reactors Of Polymerization

    Directory of Open Access Journals (Sweden)

    Meruyert Berdieva

    2012-05-01

    Full Text Available In the work the issues of stable technological modes of operation of main devices of producing polysterol reactors have been researched as well as modes of stable operation of a chemical reactor have been presented, which enables to create optimum mode parameters of polymerization process, to prevent emergency situations of chemical reactor operation in industrial conditions.

  16. Enhancing Thai Students' Learning of Chemical Kinetics

    Science.gov (United States)

    Chairam, Sanoe; Somsook, Ekasith; Coll, Richard K.

    2009-01-01

    Chemical kinetics is an extremely important concept for introductory chemistry courses. The literature suggests that instruction in chemical kinetics is often teacher-dominated at both the secondary school and tertiary levels, and this is the case in Thailand--the educational context for this inquiry. The work reported here seeks to shift students…

  17. ACS Booklet Focuses on Chemical News

    Science.gov (United States)

    Chemical and Engineering News, 1976

    1976-01-01

    Discusses the 1976 edition of "What's Happening in Chemistry," a booklet summarizing newsworthy events in chemical research, available from the American Chemical Society. The booklet is primarily for writers, editors, and broadcasters; its aim is to generate more articles in the media about chemists and chemistry. (MLH)

  18. A Course in Chemical Reactor Design.

    Science.gov (United States)

    Takoudis, Christos G.

    1983-01-01

    Presents course outline, topics covered, and final project (doubling as a take home final exam) for a one-semester, interdisciplinary course on the design and behavior of chemical reactors. Interplay of chemical and physical rate processes is stressed in the course. (JM)

  19. UK Chemical Nuclear Data Committee: progress report

    International Nuclear Information System (INIS)

    Studies of the basic nuclear data for commercial and industrial application are monitored by the UK Chemical Nuclear Data Committee (UKCNDC). Such data are defined on the basis of chemical methods of analysis, and include half-lives, decay parameters and fission yields. Work undertaken within this area is described in this document for information. (author)

  20. Integrative Chemical-Biological Read-Across Approach for Chemical Hazard Classification

    OpenAIRE

    Low, Yen; Sedykh, Alexander; Fourches, Denis; Golbraikh, Alexander; Whelan, Maurice; Rusyn, Ivan; Tropsha, Alexander

    2013-01-01

    Traditional read-across approaches typically rely on the chemical similarity principle to predict chemical toxicity; however, the accuracy of such predictions is often inadequate due to the underlying complex mechanisms of toxicity. Here we report on the development of a hazard classification and visualization method that draws upon both chemical structural similarity and comparisons of biological responses to chemicals measured in multiple short-term assays (”biological” similarity). The Che...

  1. Chemical effects of ionizing radiation and sonic energy in the context of chemical evolution

    International Nuclear Information System (INIS)

    Ionizing radiation and sonic energy are considered as sources for chemical evolution processes. These sources have still a modest place in the interdisciplinary approach for the prebiological synthesis of organic compounds. Studies in Radiation Chemistry and Sonochemistry can provide a deeper insight into the chemical processes that may have importance for prebiotic chemistry. The present work concerns the analysis of some chemical reactions induced by ionizing radiation or cavitation in aqueous media that may be relevant to chemical evolution studies. (author)

  2. Multimedia environmental chemical partitioning from molecular information

    International Nuclear Information System (INIS)

    The prospect of assessing the environmental distribution of chemicals directly from their molecular information was analyzed. Multimedia chemical partitioning of 455 chemicals, expressed in dimensionless compartmental mass ratios, was predicted by SimpleBox 3, a Level III Fugacity model, together with the propagation of reported uncertainty for key physicochemical and transport properties, and degradation rates. Chemicals, some registered in priority lists, were selected according to the availability of experimental property data to minimize the influence of predicted information in model development. Chemicals were emitted in air or water in a fixed geographical scenario representing the Netherlands and characterized by five compartments (air, water, sediments, soil and vegetation). Quantitative structure-fate relationship (QSFR) models to predict mass ratios in different compartments were developed with support vector regression algorithms. A set of molecular descriptors, including the molecular weight and 38 counts of molecular constituents were adopted to characterize the chemical space. Out of the 455 chemicals, 375 were used for training and testing the QSFR models, while 80 were excluded from model development and were used as an external validation set. Training and test chemicals were selected and the domain of applicability (DOA) of the QSFRs established by means of self-organizing maps according to structural similarity. Best results were obtained with QSFR models developed for chemicals belonging to either the class [C] and [C; O], or the class with at least one heteroatom different than oxygen in the structure. These two class-specific models, with respectively 146 and 229 chemicals, showed a predictive squared coefficient of q2 ≥ 0.90 both for air and water, which respectively dropped to q2 ∼ 0.70 and 0.40 for outlying chemicals. Prediction errors were of the same order of magnitude as the deviations associated to the uncertainty of the

  3. Chemical Sciences Division: Annual report 1992

    International Nuclear Information System (INIS)

    The Chemical Sciences Division (CSD) is one of twelve research Divisions of the Lawrence Berkeley Laboratory, a Department of Energy National Laboratory. The CSD is composed of individual groups and research programs that are organized into five scientific areas: Chemical Physics, Inorganic/Organometallic Chemistry, Actinide Chemistry, Atomic Physics, and Physical Chemistry. This report describes progress by the CSD for 1992. Also included are remarks by the Division Director, a description of work for others (United States Office of Naval Research), and appendices of the Division personnel and an index of investigators. Research reports are grouped as Fundamental Interactions (Photochemical and Radiation Sciences, Chemical Physics, Atomic Physics) or Processes and Techniques (Chemical Energy, Heavy-Element Chemistry, and Chemical Engineering Sciences)

  4. Chemical composition of Earth-like planets

    CERN Document Server

    Ronco, M P; Marboeuf, U; Alibert, Y; de Elía, G C; Guilera, O M

    2015-01-01

    Models of planet formation are mainly focused on the accretion and dynamical processes of the planets, neglecting their chemical composition. In this work, we calculate the condensation sequence of the different chemical elements for a low-mass protoplanetary disk around a solar-type star. We incorporate this sequence of chemical elements (refractory and volatile elements) in our semi-analytical model of planet formation which calculates the formation of a planetary system during its gaseous phase. The results of the semi-analytical model (final distributions of embryos and planetesimals) are used as initial conditions to develope N-body simulations that compute the post-oligarchic formation of terrestrial-type planets. The results of our simulations show that the chemical composition of the planets that remain in the habitable zone has similar characteristics to the chemical composition of the Earth. However, exist differences that can be associated to the dynamical environment in which they were formed.

  5. Chemical risk: strategies for social intervention

    Directory of Open Access Journals (Sweden)

    A. A. Calera Rubio

    2002-06-01

    Full Text Available Production, use, marketing and emission of chemical substances display the strong links between chemical risks at the workplace, healthcare and environmental pollution. In spite of this fact, the policies for the management of chemical risk are far from being coherent and unified in the different sectors. (Nutritional safety, agriculture, healthcare, environment and occupational health.The Commission of European Communities (EC has elaborated a White Document on the future policy on chemicals that recognizes the existing lack of control in this domain. We are facing a deep crisis of traditional strategies that are supposed to control chemical risks.It becomes essential to diversify the strategies. Some of them must aim at the improvement of information, others at the assessment of risk situations and some strategies must be directed to evaluate the possible alternatives for the solution of problems.

  6. A Phenomenographic Study on Chemical Bonding

    Directory of Open Access Journals (Sweden)

    Şenol Şen

    2013-12-01

    Full Text Available This study aims to reveal how students perceive and identify the concept of chemical bonding, and to identify and explain the misconceptions of students on this subject through phenomenographic research method, as well. The present study included 17 2nd grade students who enrolled to Inorganic Chemistry course in the Faculty of Education. Concept maps and lotus blossom technique were used as data collection tools in order to determine the perceptions and definitions of students about chemical bonding. Data analysis results determined the misconceptions of students about chemical bonding classified misconceptions under seven categories, which are, according to the results of the study, physical changes and bonding, ionic bond, formation of chemical bonding, the existence of chemical bonding, covalent bonds, metallic bonds and intermolecular bonding.

  7. Chemical Sciences Division: Annual report 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    The Chemical Sciences Division (CSD) is one of twelve research Divisions of the Lawrence Berkeley Laboratory, a Department of Energy National Laboratory. The CSD is composed of individual groups and research programs that are organized into five scientific areas: Chemical Physics, Inorganic/Organometallic Chemistry, Actinide Chemistry, Atomic Physics, and Physical Chemistry. This report describes progress by the CSD for 1992. Also included are remarks by the Division Director, a description of work for others (United States Office of Naval Research), and appendices of the Division personnel and an index of investigators. Research reports are grouped as Fundamental Interactions (Photochemical and Radiation Sciences, Chemical Physics, Atomic Physics) or Processes and Techniques (Chemical Energy, Heavy-Element Chemistry, and Chemical Engineering Sciences).

  8. Chemical reactor modeling multiphase reactive flows

    CERN Document Server

    Jakobsen, Hugo A

    2014-01-01

    Chemical Reactor Modeling closes the gap between Chemical Reaction Engineering and Fluid Mechanics.  The second edition consists of two volumes: Volume 1: Fundamentals. Volume 2: Chemical Engineering Applications In volume 1 most of the fundamental theory is presented. A few numerical model simulation application examples are given to elucidate the link between theory and applications. In volume 2 the chemical reactor equipment to be modeled are described. Several engineering models are introduced and discussed. A survey of the frequently used numerical methods, algorithms and schemes is provided. A few practical engineering applications of the modeling tools are presented and discussed. The working principles of several experimental techniques employed in order to get data for model validation are outlined. The monograph is based on lectures regularly taught in the fourth and fifth years graduate courses in transport phenomena and chemical reactor modeling, and in a post graduate course in modern reactor m...

  9. Chemical analysis of water in hydrogeology

    International Nuclear Information System (INIS)

    The aim of the monograph is to give complete information on the chemical analysis of water hydrogeology not only for the students program of Geology study (Bachelor degree study), Engineering Geology and Hydrogeology (Master's degree study) and Engineering Geology (doctoral level study), but also for students from other colleges and universities schools in Slovakia, as well as in the Czech Republic, dealing with the chemical composition of water and its quality, from different perspectives. The benefit would be for professionals with hydrogeological, water and environmental practices, who can find there all the necessary information about proper water sampling, the units used in the chemical analysis of water, expressing the proper chemical composition of water in its various parameters through classification of chemical composition of the water up to the basic features of physical chemistry at thermodynamic calculations and hydrogeochemical modelling.

  10. Chemical dependency and adolescent self-esteem.

    Science.gov (United States)

    Wasson, D; Anderson, M A

    1995-08-01

    The purpose of this descriptive study is to determine whether self-esteem differs between chemically dependent adolescents and adolescents from the general high school population. The Self-Esteem Inventory (Coopersmith, 1987) was completed by 119 adolescents (31 inpatient, 31 aftercare, and 57 general high school students) aged 13 to 18. Findings suggest that inpatient, chemically dependent adolescents have lower self-esteem than the other two groups. For the chemically dependent adolescent, nursing case management with communication among and between health care providers, school professionals, and family may facilitate successful, long-term recovery. For adolescents at risk for development of chemical dependence, nursing health promotion behaviors, such as early assessment and implementation of self-esteem-building activities, may assist in prevention of chemical dependency. PMID:7633338

  11. Fate of chemical warfare agents and toxic indutrial chemicals in landfills

    DEFF Research Database (Denmark)

    Bartelt-Hunt, D.L.; Barlaz, M.A.; Knappe, D.R.U.;

    2006-01-01

    One component of preparedness for a chemical attack is planning for the disposal of contaminated debris. To assess the feasibility of contaminated debris disposal in municipal solid waste (MSW) landfills, the fate of selected chemical warfare agents (CWAs) and toxic industrial chemicals (TICs...

  12. 78 FR 55326 - Determinations Regarding Use of Chemical Weapons in Syria Under the Chemical and Biological...

    Science.gov (United States)

    2013-09-10

    ... Determinations Regarding Use of Chemical Weapons in Syria Under the Chemical and Biological Weapons Control and..., 22 U.S.C. 5604(a), that the Government of Syria has used chemical weapons in violation of... Under Secretary of State for Political Affairs: (1) Determined that the Government of Syria has...

  13. From Chemical Forces to Chemical Rates: A Historical/Philosophical Foundation for the Teaching of Chemical Equilibrium

    Science.gov (United States)

    Quílez, Juan

    2009-09-01

    With this paper, our main aim is to contribute to the realisation of the chemical reactivity concept, tracing the historical evolution of the concept of chemical affinity that eventually supported the concept of chemical equilibrium. We will concentrate on searching for the theoretical grounds of three key chemical equilibrium ideas: ‚incomplete reaction’, ‚reversibility’ and ‚dynamics’. In addition, the paper aims to promote teachers’ philosophical/historical chemical knowledge. The starting point of this historical reconstruction will be the state of the art in the construction of the first affinity tables, based on the concept of elective affinities, during the 18th century. Berthollet reworked this idea, considering that the amount of the substances involved in a reaction was a key factor accounting for the chemical forces. Guldberg and Waage attempted to measure those forces, formulating the first affinity mathematical equations. Afterwards, the first ideas providing a molecular interpretation of the macroscopic properties of equilibrium reactions are presented. Eventually, theoretical chemists integrated previous findings into a new field: thermodynamics. This historical approach may serve as a base for an appropriate sequencing of the teaching and learning of chemical equilibrium. Hence, this paper tries to go beyond the simple development of teachers’ conceptions of the nature of chemistry, for it gives suggestions about how teachers may translate such understandings into classroom practice.

  14. Unnatural selection in chemical systems

    Science.gov (United States)

    Orgel, Leslie E.

    1995-01-01

    The theory of evolution through natural selection was proposed by Darwin and Wallace to explain how the characteristics of populations of animals change with time. An examination of their assumptions shows that the theory has much broader application than they originally envisaged. We now know that in appropriate environments RNA molecules or computer viruses, for example, can evolve. The adventure with which we are concerned is the quest for chemical systems that undergo processes analogous to Darwinian selection in the test tube. The search is not restricted to systems that are closely related to nucleic acids, although most of the available experimental evidence concerns such systems. A population of molecules satisfies all the requirements of the theory is there are different kinds of molecules in the population and if each individual molecule can direct the formation of copies of itself, then a population of molecules will adapt to a varying environment by changing its composition so as to maintain as high as possible a rate of replication. Sol Spiegelman is the inventor of 'unnatural selection'. He showed clearly that populations of RNA molecules evolve when replicated repeatedly by Q beta RNA polymerase under a chosen set of adverse reaction conditions. In the systems that he studied, the initial population was fairly homogeneous and much of the variation was created during the course of the experiment by mutation, that is, error of replication. The term 'unnatural selection' will be used loosely to describe evolution of nucleic acids or other replicatable polymers in vitro. The term 'Natural Selection' will be reserved for the evolution of living organisms and their viruses. Natural Section usually involves the coevolution of nucleic acids and proteins, while 'unnatural selection', as practiced so far, allows replicating nucleic acids to evolve but hold constant the enzymes that catalyze replication. It is widely believed that biology based on DNA, RNA, and

  15. Automated compound classification using a chemical ontology

    Directory of Open Access Journals (Sweden)

    Bobach Claudia

    2012-12-01

    Full Text Available Abstract Background Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. Results In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. Conclusions A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning

  16. Chemical characterization of bohrium (element 107)

    Science.gov (United States)

    Eichler; Bruchle; Dressler; Dullmann; Eichler; Gaggeler; Gregorich; Hoffman; Hubener; Jost; Kirbach; Laue; Lavanchy; Nitsche; Patin; Piguet; Schadel; Shaughnessy; Strellis; Taut; Tobler; Tsyganov; Turler; Vahle; Wilk; Yakushev

    2000-09-01

    The arrangement of the chemical elements in the periodic table highlights resemblances in chemical properties, which reflect the elements' electronic structure. For the heaviest elements, however, deviations in the periodicity of chemical properties are expected: electrons in orbitals with a high probability density near the nucleus are accelerated by the large nuclear charges to relativistic velocities, which increase their binding energies and cause orbital contraction. This leads to more efficient screening of the nuclear charge and corresponding destabilization of the outer d and f orbitals: it is these changes that can give rise to unexpected chemical properties. The synthesis of increasingly heavy elements, now including that of elements 114, 116 and 118, allows the investigation of this effect, provided sufficiently long-lived isotopes for chemical characterization are available. In the case of elements 104 and 105, for example, relativistic effects interrupt characteristic trends in the chemical properties of the elements constituting the corresponding columns of the periodic table, whereas element 106 behaves in accordance with the expected periodicity. Here we report the chemical separation and characterization of six atoms of element 107 (bohrium, Bh), in the form of its oxychloride. We find that this compound is less volatile than the oxychlorides of the lighter elements of group VII, thus confirming relativistic calculations that predict the behaviour of bohrium, like that of element 106, to coincide with that expected on the basis of its position in the periodic table. PMID:10993071

  17. Optimization of a chemical identification algorithm

    Science.gov (United States)

    Chyba, Thomas H.; Fisk, Brian; Gunning, Christin; Farley, Kevin; Polizzi, Amber; Baughman, David; Simpson, Steven; Slamani, Mohamed-Adel; Almassy, Robert; Da Re, Ryan; Li, Eunice; MacDonald, Steve; Slamani, Ahmed; Mitchell, Scott A.; Pendell-Jones, Jay; Reed, Timothy L.; Emge, Darren

    2010-04-01

    A procedure to evaluate and optimize the performance of a chemical identification algorithm is presented. The Joint Contaminated Surface Detector (JCSD) employs Raman spectroscopy to detect and identify surface chemical contamination. JCSD measurements of chemical warfare agents, simulants, toxic industrial chemicals, interferents and bare surface backgrounds were made in the laboratory and under realistic field conditions. A test data suite, developed from these measurements, is used to benchmark algorithm performance throughout the improvement process. In any one measurement, one of many possible targets can be present along with interferents and surfaces. The detection results are expressed as a 2-category classification problem so that Receiver Operating Characteristic (ROC) techniques can be applied. The limitations of applying this framework to chemical detection problems are discussed along with means to mitigate them. Algorithmic performance is optimized globally using robust Design of Experiments and Taguchi techniques. These methods require figures of merit to trade off between false alarms and detection probability. Several figures of merit, including the Matthews Correlation Coefficient and the Taguchi Signal-to-Noise Ratio are compared. Following the optimization of global parameters which govern the algorithm behavior across all target chemicals, ROC techniques are employed to optimize chemical-specific parameters to further improve performance.

  18. Chemical characterization of bohrium (element 107)

    Science.gov (United States)

    Eichler, R.; Brüchle, W.; Dressler, R.; Düllmann, Ch. E.; Eichler, B.; Gäggeler, H. W.; Gregorich, K. E.; Hoffman, D. C.; Hübener, S.; Jost, D. T.; Kirbach, U. W.; Laue, C. A.; Lavanchy, V. M.; Nitsche, H.; Patin, J. B.; Piguet, D.; Schädel, M.; Shaughnessy, D. A.; Strellis, D. A.; Taut, S.; Tobler, L.; Tsyganov, Y. S.; Türler, A.; Vahle, A.; WiIk, P. A.; Yakushev, A. B.

    2000-09-01

    The arrangement of the chemical elements in the periodic table highlights resemblances in chemical properties, which reflect the elements' electronic structure. For the heaviest elements, however, deviations in the periodicity of chemical properties are expected: electrons in orbitals with a high probability density near the nucleus are accelerated by the large nuclear charges to relativistic velocities, which increase their binding energies and cause orbital contraction. This leads to more efficient screening of the nuclear charge and corresponding destabilization of the outer d and f orbitals: it is these changes that can give rise to unexpected chemical properties. The synthesis of increasingly heavy elements, now including that of elements 114, 116 and 118, allows the investigation of this effect, provided sufficiently long-lived isotopes for chemical characterization are available. In the case of elements 104 and 105, for example, relativistic effects interrupt characteristic trends in the chemical properties of the elements constituting the corresponding columns of the periodic table, whereas element 106 behaves in accordance with the expected periodicity. Here we report the chemical separation and characterization of six atoms of element 107 (bohrium, Bh), in the form of its oxychloride. We find that this compound is less volatile than the oxychlorides of the lighter elements of group VII, thus confirming relativistic calculations that predict the behaviour of bohrium, like that of element 106, to coincide with that expected on the basis of its position in the periodic table.

  19. Chemical waste management in Hong Kong

    International Nuclear Information System (INIS)

    This paper reports that in Hong Kong, the control of chemical wastes is provided for in the Waste Disposal Ordinance. The enabling regulations of the Ordinance are presently being drafted and will be enforced in the near future. Presently, because of the lack of legislative control together with a general lack of knowledge on chemical wastes (such as mineral oils and fuel oils) and the unavailability of suitable treatment facilities, the majority of the chemical wastes generated are being discharged into the sewers or drains. In order that the control regulations can function effectively, it is decided that a Chemical Waste Treatment Center (CWTC) has to be provided by Government to ensure that the proper treatment facilities are available to the industry in the first place. As the majority of the chemical waste producers in Hong Kong are small generators, it is envisaged that most of these waste generators will have to rely on the CWTC for the proper treatment of their chemical wastes. The CWTC will also provide a waste collection service to collect and transport the chemical wastes from the industrial establishments to the CWTC. The waste generators are required to provide sufficient interim storage for their waste prior to their collection

  20. Testing and evaluation of eight decontamination chemicals

    International Nuclear Information System (INIS)

    This report covers experimental work comparing eight different decontamination chemicals. Seven of these chemicals have some novelty, or are not currently in use at the ICPP. The eighth is a common ICPP decontamination reagent used as a baseline for effective comparison. Decontamination factors, waste generation values, and corrosion rates are tabulated for these chemicals. Recommendations are given for effective methods of non-sodium or low-sodium decontamination chemicals. The two most effective chemical for decontamination found in these test were a dilute hydrofluoric and nitric acid (HF/HNO3) mixture and a fluoroboric acid solution. The fluoroboric acid solution (1 molar) was by far the most effective decontamination reagent, but suffered the problem of generating significant final calcine volume. The HF/HNO3 solution performed a very good decontamination of the SIMCON coupons while generating only small amounts of calcine volume. Concentration variables were also tested, and optimized for these two solutions. Several oxidation/reduction decon chemical systems were also tested. These systems were similar to the TURCO 4502 and TURCO 4521 solutions used for general decontamination at the ICPP. A low sodium alternative, nitric acid/potassium permanganate, to the ''high sodium'' TURCO 4502 was tested extensively, optimized and recommended for general ICPP use. A reductive chemical solution, oxalic acid/nitric acid was also shown to have significant advantages

  1. Research on the chemical speciation of actinides

    International Nuclear Information System (INIS)

    A demand for the safe and effective management of spent nuclear fuel and radioactive waste generated from nuclear power plant draws increasing attention with the growth of nuclear power industry. The objective of this project is to establish the basis of research on the actinide chemistry by using highly sensitive and advanced laser-based spectroscopic systems. Researches on the chemical speciation of actinides are prerequisite for the development of technologies related to nuclear fuel cycles, especially, such as the safe management of high level radioactive wastes and the chemical examination of irradiated nuclear fuels. For supporting these technologies, laser-based spectroscopies have been applied for the chemical speciation of actinide in aqueous solutions and the quantitative analysis of actinide isotopes in spent nuclear fuels. In this report, results on the following subjects have been summarized. Development of TRLFS technology for the chemical speciation of actinides, Development of laser-induced photo-acoustic spectroscopy (LPAS) system, Application of LIBD technology to investigate dynamic behaviors of actinides dissolution reactions, Development of nanoparticle analysis technology in groundwater using LIBD, Chemical speciation of plutonium complexes by using a LWCC system, Development of LIBS technology for the quantitative analysis of actinides, Evaluation on the chemical reactions between actinides and humic substances, Spectroscopic speciation of uranium-ligand complexes in aqueous solution, Chemical speciation of actinides adsorbed on metal oxides surfaces

  2. The Architecture of Chemical Alternatives Assessment.

    Science.gov (United States)

    Geiser, Kenneth; Tickner, Joel; Edwards, Sally; Rossi, Mark

    2015-12-01

    Chemical alternatives assessment is a method rapidly developing for use by businesses, governments, and nongovernment organizations seeking to substitute chemicals of concern in production processes and products. Chemical alternatives assessment is defined as a process for identifying, comparing, and selecting safer alternatives to chemicals of concern (including those in materials, processes, or technologies) on the basis of their hazards, performance, and economic viability. The process is intended to provide guidance for assuring that chemicals of concern are replaced with safer alternatives that are not likely to be later regretted. Conceptually, the assessment methods are developed from a set of three foundational pillars and five common principles. Based on a number of emerging alternatives assessment initiatives, in this commentary, we outline a chemical alternatives assessment blueprint structured around three broad steps: Scope, Assessment, and Selection and Implementation. Specific tasks and tools are identified for each of these three steps. While it is recognized that on-going practice will further refine and develop the method and tools, it is important that the structure of the assessment process remain flexible, adaptive, and focused on the substitution of chemicals of concern with safer alternatives. PMID:26630442

  3. Chemical Sniffing Instrumentation for Security Applications.

    Science.gov (United States)

    Giannoukos, Stamatios; Brkić, Boris; Taylor, Stephen; Marshall, Alan; Verbeck, Guido F

    2016-07-27

    Border control for homeland security faces major challenges worldwide due to chemical threats from national and/or international terrorism as well as organized crime. A wide range of technologies and systems with threat detection and monitoring capabilities has emerged to identify the chemical footprint associated with these illegal activities. This review paper investigates artificial sniffing technologies used as chemical sensors for point-of-use chemical analysis, especially during border security applications. This article presents an overview of (a) the existing available technologies reported in the scientific literature for threat screening, (b) commercially available, portable (hand-held and stand-off) chemical detection systems, and (c) their underlying functional and operational principles. Emphasis is given to technologies that have been developed for in-field security operations, but laboratory developed techniques are also summarized as emerging technologies. The chemical analytes of interest in this review are (a) volatile organic compounds (VOCs) associated with security applications (e.g., illegal, hazardous, and terrorist events), (b) chemical "signatures" associated with human presence, and PMID:27388215

  4. Implementing the chemical weapons convention

    International Nuclear Information System (INIS)

    In 1993, as the CWC ratification process was beginning, concerns arose that the complexity of integrating the CWC with national law could cause each nation to implement the Convention without regard to what other nations were doing, thereby causing inconsistencies among States as to how the CWC would be carried out. As a result, the author's colleagues and the author prepared the Manual for National Implementation of the Chemical Weapons Convention and presented it to each national delegation at the December 1993 meeting of the Preparatory Commission in The Hague. During its preparation, the Committee of CWC Legal Experts, a group of distinguished international jurists, law professors, legally-trained diplomats, government officials, and Parliamentarians from every region of the world, including Central Europe, reviewed the Manual. In February 1998, they finished the second edition of the Manual in order to update it in light of developments since the CWC entered into force on 29 April 1997. The Manual tries to increase understanding of the Convention by identifying its obligations and suggesting methods of meeting them. Education about CWC obligations and available alternatives to comply with these requirements can facilitate national response that are consistent among States Parties. Thus, the Manual offers options that can strengthen international realization of the Convention's goals if States Parties act compatibly in implementing them. Equally important, it is intended to build confidence that the legal issues raised by the Convention are finite and addressable. They are now nearing competition of an internet version of this document so that interested persons can access it electronically and can view the full text of all of the national implementing legislation it cites. The internet address, or URL, for the internet version of the Manual is http: //www.cwc.ard.gov. This paper draws from the Manual. It comparatively addresses approximately thirty

  5. Implementing the chemical weapons convention

    Energy Technology Data Exchange (ETDEWEB)

    Kellman, B.; Tanzman, E. A.

    1999-12-07

    In 1993, as the CWC ratification process was beginning, concerns arose that the complexity of integrating the CWC with national law could cause each nation to implement the Convention without regard to what other nations were doing, thereby causing inconsistencies among States as to how the CWC would be carried out. As a result, the author's colleagues and the author prepared the Manual for National Implementation of the Chemical Weapons Convention and presented it to each national delegation at the December 1993 meeting of the Preparatory Commission in The Hague. During its preparation, the Committee of CWC Legal Experts, a group of distinguished international jurists, law professors, legally-trained diplomats, government officials, and Parliamentarians from every region of the world, including Central Europe, reviewed the Manual. In February 1998, they finished the second edition of the Manual in order to update it in light of developments since the CWC entered into force on 29 April 1997. The Manual tries to increase understanding of the Convention by identifying its obligations and suggesting methods of meeting them. Education about CWC obligations and available alternatives to comply with these requirements can facilitate national response that are consistent among States Parties. Thus, the Manual offers options that can strengthen international realization of the Convention's goals if States Parties act compatibly in implementing them. Equally important, it is intended to build confidence that the legal issues raised by the Convention are finite and addressable. They are now nearing competition of an internet version of this document so that interested persons can access it electronically and can view the full text of all of the national implementing legislation it cites. The internet address, or URL, for the internet version of the Manual is http: //www.cwc.ard.gov. This paper draws from the Manual. It comparatively addresses approximately thirty

  6. Board on chemical sciences and technology

    International Nuclear Information System (INIS)

    The Board on Chemical Sciences and Technology organizes and provides direction for standing and ad hoc committees charged with addressing specific issues relevant to the continued health of the chemical sciences and technology community. Studies currently under the oversight of the BCST include a major survey of chemical engineering, an examination of the problems of biohazards in the laboratory, and an analysis of the roots and magnitude of the problem of obsolescent facilities for research and teaching in departments in the chemical sciences and engineering. The Board continues to respond to specific agency requests for program assessments and advice. BCST members are designated to serve as liaison with major federal agencies or departments that support research in order to help identify ways for the board to assist the these organizations. The BCST also maintains close contact with professional societies and nongovernmental organizations that share the Board's concern for the health of chemical sciences and technology. Individual Board members are assigned responsibility for liaison with the American Chemical Society, the American Institute of Chemical Engineers, the American Society of Biological Chemists, the Council for Chemical Research, the Chemistry and Biochemistry Sections of the National Academy of Sciences (NAS), and the National Academy of Engineering (NAE). In the past few years, the Board has served as a focus and a forum for a variety of issues that relate specifically to the health of chemistry. A sampling of these concerns include: industry-university cooperation; basic research funding in DOD, DOE, NIH, and NSF; basic research in the chemistry of life processes; basic research in biochemical engineering; basic research in the science and technology of new materials; and undergraduate education in chemistry and chemical engineering

  7. Platform Chemicals from an Oilseed Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    Tupy, Mike; Schrodi Yann

    2006-11-06

    The US chemical industry is $460 billion in size where a $150 billion segment of which is non-oxygenated chemicals that is sourced today via petroleum but is addressable by a renewable feedstock if one considers a more chemically reduced feedstock such as vegetable oils. Vegetable oil, due to its chemical functionality, provides a largely untapped opportunity as a renewable chemical source to replace petroleum-derived chemicals and produce platform chemicals unavailable today. This project examined the fertile intersection between the rich building blocks provided by vegetable oils and the enhanced chemical modification capability provided by metathesis chemistry. The technology advanced in this study is the process of ethylene cross-metathesis (referred to as ethenolysis) with vegetable oil and vegetable oil derivatives to manufacture the platform-chemical 9-decenoic acid (or 9DA) and olefin co-products. The project team meet its goals of demonstrating improved catalyst efficiencies of several multiples, deepening the mechanistic understanding of metathesis, synthesis and screening of dozens of new catalysts, designing and modeling commercial processes, and estimating production costs. One demonstrable result of the study was a step change improvement in catalyst turnover number in the ethenolysis of methyl oleate as reported here. We met our key measurable of producing 100 lbs of 9DA at the pilot-scale, which demonstrated ability to scale-up ethenolysis. DOE Project funding had significant positive impact on development of metathetically modified vegetable oils more broadly as the Cargill/Materia partnership, that was able to initiate primarily due to DOE funding, has succeeded in commercializing products, validating metathesis as a platform technology, and expanding a diverse products portfolio in high value and in large volume markets. Opportunities have expanded and business development has gained considerable momentum and enabled further expansion of the

  8. Teaching and Learning in Chemical Product Engineering - an Evolving par of the Chemical Engineering Curriculum

    DEFF Research Database (Denmark)

    Vigild, Martin Etchells; Kiil, Søren; Wesselingh, Johannes

    2007-01-01

    helping the individual to become more assertive and understanding of personal assets. These teaching elements included in Chemical Product Engineering represent a series of general issues in Chemical Engineering Education, which must be discussed as the education is going to adapt to the changes of the......Over the last decade Chemical Product Engineering has evolved as part of the Chemical Engineering Curriculum at several universities in Europe and America. At the DTU Chemical Product Engineering was introduced in 2000. This presentation will report on the experiences gained from teaching classes...... and preparing a text book on the subject. [1] Chemical Product Engineering is solidly based on chemical technical and engineering knowledge. Furthermore, the subject naturally calls for a holistic approach to teaching and learning and introduces elements which target transferable and professional...

  9. Geometric effects on carbon-13 chemical shifts

    International Nuclear Information System (INIS)

    In the course of our investigations on carbon-13 chemical shifts of tetracyclic dodecanes, we managed to show that a large number of chemical shift differences between members of the series and models provided by bicyclic analogs could be attributed to steric effects. There are examples, however, where this is clearly not the case. In order to investigate apparent anomalies we calculated structures of interest and looked into the relationships between molecular geometry and chemical shifts. As the assignment of some of the key structures in these analysis were made by comparison with model compounds and crucial experiments that could remove ambiguities were missing, we prepared and interpreted two spectra which are presented

  10. Flows and chemical reactions in heterogeneous mixtures

    CERN Document Server

    Prud'homme, Roger

    2014-01-01

    This book - a sequel of previous publications 'Flows and Chemical Reactions' and 'Chemical Reactions in Flows and Homogeneous Mixtures' - is devoted to flows with chemical reactions in heterogeneous environments.  Heterogeneous media in this volume include interfaces and lines. They may be the site of radiation. Each type of flow is the subject of a chapter in this volume. We consider first, in Chapter 1, the question of the generation of environments biphasic individuals: dusty gas, mist, bubble flow.  Chapter 2 is devoted to the study at the mesoscopic scale: particle-fluid exchange of mom

  11. Chemical history of molecules in circumstellar disks

    OpenAIRE

    Visser, Ruud; van Dishoeck, Ewine F.; Doty, Steven D.

    2011-01-01

    The chemical composition of a protoplanetary disk is determined not only by in situ chemical processes during the disk phase, but also by the history of the gas and dust before it accreted from the natal envelope. In order to understand the disk's chemical composition at the time of planet formation, especially in the midplane, one has to go back in time and retrace the chemistry to the molecular cloud that collapsed to form the disk and the central star. Here we present a new astrochemical m...

  12. Chemical synthesis of magnetic nanocrystals: Recent progress

    International Nuclear Information System (INIS)

    Colloidal chemical synthesis of various types of magnetic nanocrystals is discussed with regard to recent discoveries. We first outline the chemical preparation of single-component magnetic nanocrystals with controlled size, shape, and uniformity based on several solution-phase methods, especially thermal decomposition and/or reduction method. Then we discuss the synthetic strategies of multi-component nanocrystals incorporating at least one magnetic component by manipulating heterogeneous nucleation and growth process. Toward the end, approaches for preparing hollow/porous magnetic nanocrystals are highlighted. We believe that the summarized chemical synthesis will pave the way for the future development of extraordinary magnetic nanocrystals. (topical review - magnetism, magnetic materials, and interdisciplinary research)

  13. Chemicals used in the rubber industry.

    Science.gov (United States)

    Fishbein, L

    1991-01-01

    Hundreds of chemicals and mixtures illustrative of many structural and use categories are employed in the rubber industry. Global utilization of natural rubber and synthetic elastomers as well as rubber-processing chemicals are projected to increase in the foreseeable future. Primary focus is centered on the major rubber processing chemicals and elastomer monomers in regard to their utility, production trends, structural characteristics, nature of potential impurities, and toxicology (primarily carcinogenicity and genotoxicity). Additionally, areas of specific exposure concern and epidemiology in the rubber industry are considered. PMID:2057768

  14. Chemicals Industry New Process Chemistry Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2000-08-01

    The Materials Technology I workshop was held in November 1998 to address future research needs for materials technology that will support the chemical industry. Areas covered included disassembly, recovery, reuse and renewable technology; new materials; and materials measurement and characterization. The Materials Technology II workshop was held in September 1999 and covered additives, modeling and prediction and an additional segment on new materials. Materials Technology Institute (MTI) for the Chemical Process Industries, Inc. and Air Products & Chemicals lead the workshops. The Materials Technology Roadmap presents the results from both workshops.

  15. Radiation, chemicals, and occupational health research

    International Nuclear Information System (INIS)

    Radiation protection and its interplay with physical research programs are described. Differences and similarities between problems in health protection for chemicals and for radiation are discussed. The importance of dosimetry in radiation work and its relevance to chemicals are cited. A collaborative program between physical and biological scientists on the toxicity of metals is briefly described. It serves as an example of new research directed toward the development of fundamental concepts and principles as a basis for understanding and controlling occupational and population exposures to chemicals. 12 references, 4 figures

  16. Nanotube-Based Chemical and Biomolecular Sensors

    Institute of Scientific and Technical Information of China (English)

    J.Koh; B.Kim; S.Hong; H.Lim; H.C.Choi

    2008-01-01

    We present a brief review about recent results regarding carbon nanotube (CNT)-based chemical and biomolecular sensors. For the fabrication of CNT-based sensors, devices containing CNT channels between two metal electrodes are first fabricated usually via chemical vapor deposition (CVD) process or "surface programmed assembly" method. Then, the CNT surfaces are often functionalized to enhance the selectivity of the sensors. Using this process, highly-sensitive CNT-based sensors can be fabricated for the selective detection of various chemical and biological molecules such as hydrogen, ammonia, carbon monoxide, chlorine gas, DNA, glucose, alcohol, and proteins.

  17. Production of chemicals and fuels from biomass

    Energy Technology Data Exchange (ETDEWEB)

    Woods, Elizabeth; Qiao, Ming; Myren, Paul; Cortright, Randy D.; Kania, John

    2015-12-15

    Described are methods, reactor systems, and catalysts for converting biomass to fuels and chemicals in a batch and/or continuous process. The process generally involves the conversion of water insoluble components of biomass, such as hemicellulose, cellulose and lignin, to volatile C.sub.2+O.sub.1-2 oxygenates, such as alcohols, ketones, cyclic ethers, esters, carboxylic acids, aldehydes, and mixtures thereof. In certain applications, the volatile C.sub.2+O.sub.1-2 oxygenates can be collected and used as a final chemical product, or used in downstream processes to produce liquid fuels, chemicals and other products.

  18. MR chemical shift imaging of human atheroma

    International Nuclear Information System (INIS)

    The lipid content of atheromatous plaques has been measured with chemical shift MR imaging by taking advantage of the different resonance frequencies of protons in lipid and water. Fifteen postmortem aortic specimens of the human descending aorta and the aortae of seven patients with documented peripheral vascular disease were studied at 0.5 T. Spin-echo images were used to localize the lesions before acquisition of the chemical shift images. The specimens were examined histologically, and the lipid distribution in the plaque showed good correlation with the chemical shift data. Validation in vivo and clinical applications remain to be established

  19. Rhizosphere chemical dialogues: plant-microbe interactions

    Energy Technology Data Exchange (ETDEWEB)

    Badri, D.V.; van der Lelie, D.; Weir, T. L.; Vivanco, J. M.

    2009-12-01

    Every organism on earth relies on associations with its neighbors to sustain life. For example, plants form associations with neighboring plants, microflora, and microfauna, while humans maintain symbiotic associations with intestinal microbial flora, which is indispensable for nutrient assimilation and development of the innate immune system. Most of these associations are facilitated by chemical cues exchanged between the host and the symbionts. In the rhizosphere, which includes plant roots and the surrounding area of soil influenced by the roots, plants exude chemicals to effectively communicate with their neighboring soil organisms. Here we review the current literature pertaining to the chemical communication that exists between plants and microorganisms and the biological processes they sustain.

  20. Autonomous Chemical Vapour Detection by Micro UAV

    OpenAIRE

    Kent Rosser; Karl Pavey; Nicholas FitzGerald; Anselm Fatiaki; Daniel Neumann; David Carr; Brian Hanlon; Javaan Chahl

    2015-01-01

    The ability to remotely detect and map chemical vapour clouds in open air environments is a topic of significant interest to both defence and civilian communities. In this study, we integrate a prototype miniature colorimetric chemical sensor developed for methyl salicylate (MeS), as a model chemical vapour, into a micro unmanned aerial vehicle (UAV), and perform flights through a raised MeS vapour cloud. Our results show that that the system is capable of detecting MeS vapours at low ppm con...