WorldWideScience

Sample records for solution chemistry effects

  1. Aqueous Solution Chemistry of Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Clark, David L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-28

    Things I have learned working with plutonium: Chemistry of plutonium is complex; Redox equilibria make Pu solution chemistry particularly challenging in the absence of complexing ligands; Understanding this behavior is key to successful Pu chemistry experiments; There is no suitable chemical analog for plutonium.

  2. Effects of solution chemistry and aging time on prion protein adsorption and replication of soil-bound prions.

    Directory of Open Access Journals (Sweden)

    Samuel E Saunders

    2011-04-01

    Full Text Available Prion interactions with soil may play an important role in the transmission of chronic wasting disease (CWD and scrapie. Prions are known to bind to a wide range of soil surfaces, but the effects of adsorption solution chemistry and long-term soil binding on prion fate and transmission risk are unknown. We investigated HY TME prion protein (PrP(Sc adsorption to soil minerals in aqueous solutions of phosphate buffered saline (PBS, sodium chloride, calcium chloride, and deionized water using western blotting. The replication efficiency of bound prions following adsorption in these solutions was also evaluated by protein misfolding cyclic amplification (PMCA. Aging studies investigated PrP(Sc desorption and replication efficiency up to one year following adsorption in PBS or DI water. Results indicate that adsorption solution chemistry can affect subsequent prion replication or desorption ability, especially after incubation periods of 30 d or longer. Observed effects were minor over the short-term (7 d or less. Results of long-term aging experiments demonstrate that unbound prions or prions bound to a diverse range of soil surfaces can readily replicate after one year. Our results suggest that while prion-soil interactions can vary with solution chemistry, prions bound to soil could remain a risk for transmitting prion diseases after months in the environment.

  3. Radiation chemistry of aqueous solutions of hydrazine at elevated temperatures: Pt. 2. Solutions containing oxygen

    International Nuclear Information System (INIS)

    Buxton, G.V.; Stuart, C.R.

    1997-01-01

    Here, we investigate the effects of oxygen on the radiation chemistry of hydrazine at elevated temperatures. The chemistry of this system is important to reactor coolant chemistry, particularly under start-up conditions when hydrazine is added to suppress corrosion which would otherwise be caused by the ingress of oxygen. The radiation chemistry of aqueous solutions of hydrazine has been investigated previously in the presence of oxygen by Ershov et al., but only at room temperature. In those experiments, both steady-state γ-radiolysis and pulse radiolysis were used to deduce the mechanism of decomposition of hydrazine in the presence of oxygen. (author)

  4. The aluminum chemistry and corrosion in alkaline solutions

    International Nuclear Information System (INIS)

    Zhang Jinsuo; Klasky, Marc; Letellier, Bruce C.

    2009-01-01

    Aluminum-alkaline solution systems are very common in engineering applications including nuclear engineering. Consequently, a thorough knowledge of the chemistry of aluminum and susceptibility to corrosion in alkaline solutions is reviewed. The aluminum corrosion mechanism and corrosion rate are examined based on current experimental data. A review of the phase transitions with aging time and change of environment is also performed. Particular attention is given to effect of organic and inorganic ions. As an example, the effect of boron is examined in detail because of the application in nuclear reactor power systems. Methods on how to reduce the corrosion rate of aluminum in alkaline solutions are also highlighted

  5. Solution chemistry of carbonate minerals and its effects on the flotation of hematite with sodium oleate

    Science.gov (United States)

    Li, Dong; Yin, Wan-zhong; Xue, Ji-wei; Yao, Jin; Fu, Ya-feng; Liu, Qi

    2017-07-01

    The effects of carbonate minerals (dolomite and siderite) on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared (FTIR) spectroscopic studies, and X-ray photoelectron spectroscopy (XPS) analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations (Ca2+ and Mg2+) and CO3 2- ions dissolved from dolomite depressed hematite flotation, whereas only the CO3 2- ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca2+, Mg2+, and CO3 2- (HCO3 -) could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.

  6. Radiation chemistry of aqueous solutions of acetonitrile and propionitrile

    International Nuclear Information System (INIS)

    Shushtarian, M.J.

    1975-01-01

    The radiation chemistry of water and aqueous solutions is a branch of radiation chemistry dealing with chemical changes in water and aqueous solutions induced by high energy radiations. High energy radiations of interest in radiation chemistry are short-wave electromagnetic radiations (X- and γ-rays) and fast charged particles (α- and β-particles, electrons, deuterons and fission fragments). The energy of the particles and photons bringing about chemical reactions in the field of modern radiation chemistry is much higher than that of photons causing photochemical reactions

  7. Organoactinide chemistry: synthesis, structure, and solution dynamics

    International Nuclear Information System (INIS)

    Brennan, J.G.

    1985-12-01

    This thesis considers three aspects of organoactinide chemistry. In chapter one, a bidentate phosphine ligand was used to kinetically stabilize complexes of the type Cp 2 MX 2 . Ligand redistribution processes are present throughout the synthetic work, as has often been observed in uranium cyclopentadienyl chemistry. The effects of covalent M-L bonding on the solution and solid state properties of U(III) coordination complexes are considered. In particular, the nature of the more subtle interaction between the metal and the neutral ligand are examined. Using relative basicity data obtained in solution, and solid state structural data (and supplemented by gas phase photoelectron measurements), it is demonstrated that the more electron rich U(III) centers engage in significant U → L π-donation. Trivalent uranium is shown to be capable of acting either as a one- or two-electron reducing agent toward a wide variety of unsaturated organic and inorganic molecules, generating molecular classes unobtainable via traditional synthetic approaches, as well as offering an alternative synthetic approach to molecules accessible via metathesis reactions. Ligand redistribution processes are again observed, but given the information concerning ligand lability, this reactivity pattern is applied to the synthesis of pure materials inaccessible from redox chemistry. 214 refs., 33 figs., 10 tabs

  8. Molybdenum: the element and aqueous solution chemistry

    International Nuclear Information System (INIS)

    Sykes, A.G.

    1987-01-01

    This chapter on the chemistry of the coordination compounds of molybdenum concentrates on the element itself, its recovery from ores and its use in the manufacture of steels. Most of the chapter is devoted to the aqueous solution chemistry of molybdenum in oxidation states II, III and IV. (UK)

  9. Complex chemistry of Np(V) in aqueous solutions

    International Nuclear Information System (INIS)

    Inoue, Yasushi

    1989-01-01

    Despite the importance of Np(V) in both the nuclear chemical engineering and the actinoid chemistry, little work has been performed on the complex chemistry of Np(V) in aqueous solutions, since Np(V) reacts less readily with various ligands. The author has directed his effort to understand the chemical behavior of Np(V) in aqueous solutions, especially the determination of the stability constants of Np(V) complexes with various ligands. A part of the results obtained so far is presented in the following order. (1) The synergistic extraction of Np(V) as a method for studying the complex chemistry of Np(V): TTA-MTOA(methyltrioctylammonium chloride), TTA-phen and TTA-TOPO. (2) The determination of the stability constants of Np(V) complexes with 22 organic- and 5 inorganic ligands by means of the solvent extraction. (3) The distribution of the chemical species of Np(V) in solutions under various conditions

  10. Coupled effects of solution chemistry and hydrodynamics on the mobility and transport of quantum dot nanomaterials in the Vadose Zone

    Science.gov (United States)

    To investigate the coupled effects of solution chemistry and vadose zone processes on the mobility of quantum dot (QD) nanoparticles, laboratory scale transport experiments were performed. The complex coupled effects of ionic strength, size of QD aggregates, surface tension, contact angle, infiltrat...

  11. Solutions to selected exercise problems in quantum chemistry and spectroscopy

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens

    2016-01-01

    Suggested solutions to a number of problems from the collection "Exercise Problems in Quantum Chemistry and Spectroscopy", previously published on ResearchGate (DOI: 10.13140/RG.2.1.4024.8162).......Suggested solutions to a number of problems from the collection "Exercise Problems in Quantum Chemistry and Spectroscopy", previously published on ResearchGate (DOI: 10.13140/RG.2.1.4024.8162)....

  12. Solution chemistry techniques in SYNROC preparation

    International Nuclear Information System (INIS)

    Dosch, R.G.; Lynch, A.W.

    1981-07-01

    Investigations of titanate-based ceramic forms for radioactive waste immobilization are underway at Sandia National Laboratories (SNLA) and at Lawrence Livermore National Laboratory (LLNL). Although the waste forms differ as to overall product composition, the waste-containing phases in both ceramic products have similar crystalline structure types. These include metallic phases along with oxides with structure types of the mineral analogues perovskite, zirconolite, and hollandite. Significant differences also exist in the area of processing. More conventional ceramic processing methods are used at LLNL to produce SYNROC while solution chemistry techniques involving metal alkoxide chemistry and ion exchange have been developed at SNLA to prepare calcium titanate-based waste ceramics. The SNLA techniques were recently modified and applied to producing SYNROC (compositions C and D) as part of an interlaboratory information exchange between SNLA and LLNL. This report describes the methods used in preparing SYNROC including the solution interaction, and hot-pressing methods used to obtain fully dense SYNROC monoliths

  13. Radiation chemistry of amino acids and peptides in aqueous solutions

    International Nuclear Information System (INIS)

    Simic, M.G.

    1978-01-01

    Radiation chemistry relevant to radiation preservation of high protein foods is reviewed. Some conclusions concerning the chemistry of irradiated amino acids, peptides, and proteins have been derived from product analysis of γ-irradiated solutions while the main mechanistic considerations result from the chemistry and kinetics of free radical intermediates observed by pulse radiolysis. The precursors of chemistry in not too concentrated solutions ( - , OH, and H. Their reactivity with molecules and their preference for characteristic groups within the molecule are discussed. The reviewed reactions of the model systems are accountable for a variety of radiolytic products found in irradiated foods. From detailed understanding of radiation chemistry in aqueous and frozen systems formation of many classes of compounds can be predicted or entirely eliminated in order to corroborate and extend the conclusions reached from the animal feeding experiments concerning the formation of toxic, mutagenic, and carcinogenic compounds and/or reduction of the nutritional value of foods

  14. Effects of feed solution chemistry on low pressure reverse osmosis filtration of cesium and strontium

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Shiyuan, E-mail: dingshiyuan@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Yang, Yu, E-mail: yangyu@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Huang, Haiou, E-mail: huanghaiou@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Liu, Hengchen, E-mail: 799599501@qq.com [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Hou, Li-an, E-mail: houlian678@hotmail.com [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Xi’an High-Tech Institute, No. 2, Tongxin Street, Baqiao District, Xi’an 710025 (China)

    2015-08-30

    Highlights: • A low pressure spiral wound RO membrane can reject Cs and Sr efficiently. • The rejection of Cs and Sr is dependent on feed pH and co-existing ions. • Donnan exclusion and electrostatic interaction govern the rejection of Cs and Sr. • The differences of filtration mechanism were influenced by the size of ions. • Sr could strengthen the irreversible membrane fouling resistance with HA. - Abstract: The objective of this study was to identify the removal mechanisms of radionuclides by reverse osmosis (RO) membranes under conditions relevant to full-scale water treatment. For this purpose, the effects of feed solution chemistry on the removal of Cs and Sr by a low pressure RO system was investigated by systematically varying membrane surface charge, ionic composition, and organic matter concentrations. The results showed that the effects of solution chemistry on the filtration of Cs and Sr were related to their hydrated ionic radius, resulting in the predominance of the Donnan’s effect and electrostatic interactions, respectively. Consequently, the rejection of Cs increased more pronouncedly than Sr with the increases of feed concentration. Due to the Donnan’s effect, different anions decreased the rejection of Cs to different extents in accordance to the order of anions’ radii as SO{sub 4}{sup 2−} > Cl{sup −} > NO{sub 3}{sup −} > F{sup −}. The variations in Sr rejection were influenced by the electrostatic interactions between Sr{sup 2+} and the membrane. In addition, humic acid (HA) lowered the rejection of Cs and caused significant membrane flux decline, but did not change the rejection of Sr. Sr also aggravated HA fouling of the membrane.

  15. Chemistry in high temperature aqueous solutions application to the power industry

    International Nuclear Information System (INIS)

    Cohen, P.

    1990-01-01

    The power industry utilizes water (aqueous solutions) for two main functions: as a medium for heat transfer and transport and as a thermodynamic working fluid. These functions are performed in systems fabricated from a wide variety of materials, over a wide range of thermal and hydraulic conditions, and at medium temperatures and densities which determine the significant chemical properties. The major chemical interest is in the concentrated solutions derived from the dilute working fluid at selected sites defined by the physical arrangement and temperature and in their consequential effects on heat transfer and corrosion. Examples of these sites for typical fossil fired and nuclear steam generating equipment are described, as well as the extent and limit of the concentration process. The history of steam power plant water chemistry is discussed from the point of view of the chemical processes involved. The period covered is from the 1920s to the present state of the art, which is a major application of the subject of this symposium--chemistry in high temperature aqueous solution

  16. Effect of solution chemistry on the adsorption of perfluorooctane sulfonate onto mineral surfaces.

    Science.gov (United States)

    Tang, Chuyang Y; Shiang Fu, Q; Gao, Dawen; Criddle, Craig S; Leckie, James O

    2010-04-01

    Perfluorooctane sulfonate (PFOS) is an emergent contaminant of substantial environmental concerns, yet very limited information has been available on PFOS adsorption onto mineral surfaces. PFOS adsorption onto goethite and silica was investigated by batch adsorption experiments under various solution compositions. Adsorption onto silica was only marginally affected by pH, ionic strength, and calcium concentration, likely due to the dominance of non-electrostatic interactions. In contrast, PFOS uptake by goethite increased significantly at high [H+] and [Ca2+], which was likely due to enhanced electrostatic attraction between the negatively charged PFOS molecules and positively charged goethite surface. The effect of pH was less significant at high ionic strength, likely due to electrical double layer compression. PFOS uptake was reduced at higher ionic strength for a strongly positively charged goethite surface (pH 3), while it increased for a weakly charged surface (pH 7 and 9), which could be attributed to the competition between PFOS-surface electrostatic attraction and PFOS-PFOS electrostatic repulsion. A conceptual model that captures PFOS-surface and PFOS-PFOS electrostatic interactions as well as non-electrostatic interaction was also formulated to understand the effect of solution chemistry on PFOS adsorption onto goethite and silica surfaces. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  17. Effect of wood ash application on soil solution chemistry of tropical acid soils: incubation study.

    Science.gov (United States)

    Nkana, J C Voundi; Demeyer, A; Verloo, M G

    2002-12-01

    The objective of this study was to determine the effect of wood ash application on soil solution composition of three tropical acid soils. Calcium carbonate was used as a reference amendment. Amended soils and control were incubated for 60 days. To assess soluble nutrients, saturation extracts were analysed at 15 days intervals. Wood ash application affects the soil solution chemistry in two ways, as a liming agent and as a supplier of nutrients. As a liming agent, wood ash application induced increases in soil solution pH, Ca, Mg, inorganic C, SO4 and DOC. As a supplier of elements, the increase in the soil solution pH was partly due to ligand exchange between wood ash SO4 and OH- ions. Large increases in concentrations of inorganic C, SO4, Ca and Mg with wood ash relative to lime and especially increases in K reflected the supply of these elements by wood ash. Wood ash application could represent increased availability of nutrients for the plant. However, large concentrations of basic cations, SO4 and NO3 obtained with higher application rates could be a concern because of potential solute transport to surface waters and groundwater. Wood ash must be applied at reasonable rates to avoid any risk for the environment.

  18. Dense interstellar cloud chemistry: Basic issues and possible dynamical solution

    International Nuclear Information System (INIS)

    Prasad, S.S.; Heere, K.R.; Tarafdar, S.P.

    1989-01-01

    Standing at crossroad of enthusiasm and frustration, dense intertellar cloud chemistry has a squarely posed fundamental problem: Why do the grains appear to play at best a minor role in the chemistry? Grain surface chemistry creates considerable difficulties when the authors treat dense clouds as static objects and ignore the implications of the processes by which the clouds became dense in the first place. A new generation of models which treat chemical and dynamical evolutions concurrently are therefore presented as possible solution to the current frustrations. The proposed modeling philosophy and agenda could make the next decade quite exciting for interstellar chemistry

  19. Effects of simulated acid rain on soil and soil solution chemistry in a monsoon evergreen broad-leaved forest in southern China.

    Science.gov (United States)

    Qiu, Qingyan; Wu, Jianping; Liang, Guohua; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2015-05-01

    Acid rain is an environmental problem of increasing concern in China. In this study, a laboratory leaching column experiment with acid forest soil was set up to investigate the responses of soil and soil solution chemistry to simulated acid rain (SAR). Five pH levels of SAR were set: 2.5, 3.0, 3.5, 4.0, and 4.5 (as a control, CK). The results showed that soil acidification would occur when the pH of SAR was ≤3.5. The concentrations of NO₃(-)and Ca(2+) in the soil increased significantly when the pH of SAR fell 3.5. The concentration of SO₄(2-) in the soil increased significantly when the pH of SAR was soil solution chemistry became increasingly apparent as the experiment proceeded (except for Na(+) and dissolved organic carbon (DOC)). The net exports of NO₃(-), SO₄(2-), Mg(2+), and Ca(2+) increased about 42-86% under pH 2.5 treatment as compared to CK. The Ca(2+) was sensitive to SAR, and the soil could release Ca(2+) through mineral weathering to mitigate soil acidification. The concentration of exchangeable Al(3+) in the soil increased with increasing the acidity of SAR. The releases of soluble Al and Fe were SAR pH dependent, and their net exports under pH 2.5 treatment were 19.6 and 5.5 times, respectively, higher than that under CK. The net export of DOC was reduced by 12-29% under SAR treatments as compared to CK. Our results indicate the chemical constituents in the soil are more sensitive to SAR than those in the soil solution, and the effects of SAR on soil solution chemistry depend not only on the intensity of SAR but also on the duration of SAR addition. The soil and soil solution chemistry in this region may not be affected by current precipitation (pH≈4.5) in short term, but the soil and soil leachate chemistry may change dramatically if the pH of precipitation were below 3.5 and 3.0, respectively.

  20. Radiation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    None

    1973-07-01

    Research progress is reported on radiation chemistry of heavy elements that includes the following topics: radiation chemistry of plutonium in nitric acid solutions (spectrophotometric analysis and gamma radiolysis of Pu(IV) and Pu(VI) in nitric acid solution); EPR studies of intermediates formed in radiolytic reactions with aqueous medium; two-phase radiolysis and its effect on the distribution coefficient of plutonium; and radiation chemistry of nitric acid. (DHM)

  1. The radiation chemistry of aqueous sodium terephthalate solutions

    International Nuclear Information System (INIS)

    Matthews, R.W.

    1980-04-01

    The radiation chemistry of cobalt-60 gamma-irradiated aqueous sodium terephthalate solutions has been studied. In aerated 4 x 10 -4 M sodium hydroxide solutions, the main products are hydroxyterephthalate (HTA) (G = 0.99 +- 0.01), carbonate (G = 1.31 +- 0.08), and peroxides (G = 2.84 +- 0.04). The HTA and carbonate species are both formed as a result of hydroxyl radical attack and account for approximately 90 per cent of hydroxyl radical reactions. Oxygen needs to be present for efficient conversion of the terephthalate-OH radical adduct to HTA and oxygenation increases G(HTA) above the aerated solution value. G(HTA) is unaffected by changes in terephthalate concentration between 1 x 10 -4 M and 1 x 10 -2 M in sodium hydroxide solutions at pH 10. Decreasing the solution pH does however affect G(HTA). In phosphate buffered solutions pH 6.85, G(HTA) is 0.93 +- 0.01 and lower values are obtained with further decrease in solution pH. The lowering of the G(HTA) value is attributed to recombination reactions between the terephthalate-OH radical products and reducing radical products. Experimental evidence supporting the recombination postulate was obtained from the measurement of a parallel decrease in the peroxide yield and the observation of a dose rate effect on G(HTA). Competition kinetic studies with the added solutes carbonate and bicarbonate gave the rate ratios k (OH + TA 2- ) : k(OH + CO 3 2- ) : k(OH + HCO 3 - ) = 1 : 0.105 : 0.0036

  2. Effects of Solution Chemistry on Nano-Bubbles Transport in Saturated Porous Media

    Science.gov (United States)

    Hamamoto, S.; Takemura, T.; Suzuki, K.; Nihei, N.; Nishimura, T.

    2017-12-01

    Nano-bubbles (NBs) have a considerable potential for the remediation of soil and groundwater contaminated by organic compounds, especially when used in conjunction with bioremediation technologies. Understanding the transport mechanisms of NBs in soils is essential to optimize NB-based remediation techniques. In this study, one-dimensional column transport experiments using glass beads with 0.1 mm size were conducted, where NBs created by oxygen gas at different pH and ionic strength were injected to the column at the constant flow rate. The NBs concentration in the effluent was quantified using a resonant mass measurement technique. Effects of solution chemistry of the NBs water on NB transport in the porous media were investigated. The results showed that attachment of NBs was enhanced under higher ionic strength and lower pH conditions, caused by the reduced repulsive force between NBs and glass beads. In addition, bubble size distributions in the effluents showed that relatively larger NBs were retained in the column. This trend was more significant at lower pH condition.

  3. Desorption of 1,3,5-Trichlorobenzene from Multi-Walled Carbon Nanotubes: Impact of Solution Chemistry and Surface Chemistry

    Directory of Open Access Journals (Sweden)

    Sheikh Uddin

    2013-05-01

    Full Text Available The strong affinity of carbon nanotubes (CNTs to environmental contaminants has raised serious concern that CNTs may function as a carrier of environmental pollutants and lead to contamination in places where the environmental pollutants are not expected. However, this concern will not be realized until the contaminants are desorbed from CNTs. It is well recognized that the desorption of environmental pollutants from pre-laden CNTs varies with the environmental conditions, such as the solution pH and ionic strength. However, comprehensive investigation on the influence of solution chemistry on the desorption process has not been carried out, even though numerous investigations have been conducted to investigate the impact of solution chemistry on the adsorption of environmental pollutants on CNTs. The main objective of this study was to determine the influence of solution chemistry (e.g., pH, ionic strength and surface functionalization on the desorption of preloaded 1,3,5-trichlorobenzene (1,3,5-TCB from multi-walled carbon nanotubes (MWNTs. The results suggested that higher pH, ionic strength and natural organic matter in solution generally led to higher desorption of 1,3,5-TCB from MWNTs. However, the extent of change varied at different values of the tested parameters (e.g., pH 7. In addition, the impact of these parameters varied with MWNTs possessing different surface functional groups, suggesting that surface functionalization could considerably alter the environmental behaviors and impact of MWNTs.

  4. Effects of wood ash on soil solution and chemistry of leaves in a beech stand

    International Nuclear Information System (INIS)

    Tothova, Slavka

    2005-01-01

    The short-term effects of wood ash fertilization on chemistry of soil solution and leaves were investigated in 4-year-old beech stand (Fagus sylvatica L.) on dystric cambisol in Central Spis. Four plots - the control plot and three plots with different ash treatments (different dose, date and method of application) were established. Plate lysimeters were installed under the upper layer of soil in depth 2 cm and 20 cm on the control plot and plot P1 with addition of wood ash 5 t/ha on the whole surface. Soil solution was collected in May - October 2002 every two weeks. Composite samples, which represent a one - month period, were analysed for pH, K, Ca, Mg, and NO 3 - . The leaves were collected 4 or 10 months after the treatment and analysed on Ca, K, Mg, P, S, N and heavy metals Cd, Pb, Cr and Hg. In the ash treatment the content of macronutrient increased (mainly K, Ca). Addition of ash did not increase of the content heavy metal in leaves

  5. The chemistry of nonaqueous solvents v.4 solution phenomena and aprotic solvents

    CERN Document Server

    Lagowski, J J

    1976-01-01

    The Chemistry of Nonaqueous Solvents, Volume IV: Solution Phenomena and Aprotic Solvents focuses on the chemistry of nonaqueous solvents, with emphasis on solution phenomena and aprotic solvents such as tetramethylurea, inorganic acid chlorides, cyclic carbonates, and sulfolane. This book is organized into seven chapters and begins with an overview of the theory of electrical conductivity and elementary experimental considerations, along with some of the interesting research on nonaqueous solvents. It then turns to a discussion on hydrogen bonding phenomena in nonaqueous systems as probed

  6. Pre-Service Chemistry Teachers' Competencies in the Laboratory: A Cross-Grade Study in Solution Preparation

    Science.gov (United States)

    Karatas, F. O.

    2016-01-01

    One of the prerequisites for chemistry teacher candidates is to demonstrate certain laboratory skills. This article aims to determine and discuss the competencies of pre-service chemistry teachers in a chemistry laboratory context working with solution chemistry content. The participants in this study consisted of a group of pre-service chemistry…

  7. Transport of titanium dioxide nanoparticles in saturated porous media under various solution chemistry conditions

    International Nuclear Information System (INIS)

    Wang Yu; Gao Bin; Morales, Verónica L.; Tian Yuan; Wu Lei; Gao Jie; Bai Wei; Yang Liuyan

    2012-01-01

    Because of its wide applications, nanosized titanium dioxide may become a potential environmental risk to soil and groundwater system. It is therefore important to improve current understanding of the environmental fate and transport of titanium oxides nanoparticles (TONPs). In this work, the effect of solution chemistry (i.e., pH, ionic strength, and natural organic matter (NOM) concentration) on the deposition and transport of TONPs in saturated porous media was examined in detail. Laboratory columns packed with acid-cleaned quartz sand were used in the experiment as porous media. Transport experiments were conducted with various chemistry combinations, including four ionic strengths, three pH levels, and two NOM concentrations. The results showed that TONP mobility increased with increasing solution pH, but decreased with increasing solution ionic strength. It is also found that the presence of NOM in the system enhanced the mobility of TONPs in the saturated porous media. The Derjaguin–Landau–Verwey–Overbeek (DLVO) theory was used to justify the mobility trends observed in the experimental data. Predictions from the theory agreed excellently with the experimental data.

  8. Fluctuation theory of solutions applications in chemistry, chemical engineering, and biophysics

    CERN Document Server

    Smith, Paul E

    2013-01-01

    There are essentially two theories of solutions that can be considered exact: the McMillan-Mayer theory and Fluctuation Solution Theory (FST). The first is mostly limited to solutes at low concentrations, while FST has no such issue. It is an exact theory that can be applied to any stable solution regardless of the number of components and their concentrations, and the types of molecules and their sizes. Fluctuation Theory of Solutions: Applications in Chemistry, Chemical Engineering, and Biophysics outlines the general concepts and theoretical basis of FST and provides a range of applications

  9. Effects of lime and wood ash on soil-solution chemistry, soil chemistry and nutritional status of a pine stand in northern Germany

    International Nuclear Information System (INIS)

    Ludwig, Bernard; Rumpf, Sabine; Mindrup, Michael; Meiwes, Karl-Josef; Khanna, Partap K.

    2002-01-01

    Lime and wood ash may be useful to improve acidic forest soils. A field experiment was conducted in a pine stand on a sandy podzol at Fuhrberg, Germany, which involved an application of dolomitic lime (3 t/ha) with three replications or wood ash (4.8 t/ha) without replications on the forest floor. During the 2 yr study period, lime affected the soil solution composition only slightly. Ash had a marked effect on solution chemistry of the mineral soil at 10 cm and the pH values dropped temporarily from 3.7 to 3.1. Nineteen months after the treatments, exchangeable calcium in the organic layer and mineral soil increased by 222 (lime addition) or 411 kg/ha (ash addition) and exchangeable magnesium increased by 101 (lime addition) or 39 kg/ha (ash addition). After ash addition, no marked change in heavy metal content was found below 4 cm of the organic layer. In the ash treatment, the potassium concentration of the 1-yr-old pine needles increased from 5.6 to 5.9 g/kg. This study suggests that ash from untreated wood may be recommended for amelioration of forest soils

  10. Effects of atmospheric deposition nitrogen flux and its composition on soil solution chemistry from a red soil farmland, southeast China.

    Science.gov (United States)

    Cui, Jian; Zhou, Jing; Peng, Ying; Chan, Andrew; Mao, Jingdong

    2015-12-01

    A detailed study on the solution chemistry of red soil in South China is presented. Data are collected from two simulated column-leaching experiments with an improved setup to evaluate the effects of atmospheric N deposition (ADN) composition and ADN flux on agricultural soil acidification using a (15)N tracer technique and an in situ soil solution sampler. The results show that solution pH values decline regardless of the increase of the NH4(+)/NO3(-) ratio in the ADN composition or ADN flux, while exchangeable Al(3+), Ca(2+), Mg(2+), and K(+) concentrations increase at different soil depths (20, 40, and 60 cm). Compared with the control, ADN (60 kg per ha per year N, NH4(+)/NO3(-) ratio of 2 : 1) decreases solution pH values, increases solution concentrations of NO3(-)-N, Al(3+), Ca(2+) and Mg(2+) at the middle and lower soil depths, and promotes their removal. NH4(+)-N was not detected in red soil solutions of all the three soil layers, which might be attributed to effects of nitrification, absorption and fixation in farmland red soil. Some of the NO3(-)-N concentrations at 40-60 cm soil depth exceed the safe drinking level of 10 mg L(-1), especially when the ADN flux is beyond 60 kg ha(-1) N. These features are critical for understanding the ADN agro-ecological effects, and for future assessment of ecological critical loads of ADN in red soil farmlands.

  11. Impacts of operating conditions and solution chemistry on osmotic membrane structure and performance

    KAUST Repository

    Wong, Mavis C.Y.; Martinez, Kristina; Ramon, Guy Z.; Hoek, Eric M.V.

    2012-01-01

    Herein, we report on changes in the performance of a commercial cellulose triacetate (CTA) membrane, imparted by varied operating conditions and solution chemistries. Changes to feed and draw solution flow rate did not significantly alter the CTA membrane's water permeability, salt permeability, or membrane structural parameter when operated with the membrane skin layer facing the draw solution (PRO-mode). However, water and salt permeability increased with increasing feed or draw solution temperature, while the membrane structural parameter decreased with increasing draw solution, possibly due to changes in polymer intermolecular interactions. High ionic strength draw solutions may de-swell the CTA membrane via charge neutralization, which resulted in lower water permeability, higher salt permeability, and lower structural parameter. This observed trend was further exacerbated by the presence of divalent cations which tends to swell the polymer to a greater extent. Finally, the calculated CTA membrane's structural parameter was lower and less sensitive to external factors when operated in PRO-mode, but highly sensitive to the same factors when the skin layer faced the feed solution (FO-mode), presumably due to swelling/de-swelling of the saturated porous substructure by the draw solution. This is a first attempt aimed at systematically evaluating the changes in performance of the CTA membrane due to operating conditions and solution chemistry, shedding new insight into the possible advantages and disadvantages of this material in certain applications. © 2011 Elsevier B.V.

  12. Impacts of operating conditions and solution chemistry on osmotic membrane structure and performance

    KAUST Repository

    Wong, Mavis C.Y.

    2012-02-01

    Herein, we report on changes in the performance of a commercial cellulose triacetate (CTA) membrane, imparted by varied operating conditions and solution chemistries. Changes to feed and draw solution flow rate did not significantly alter the CTA membrane\\'s water permeability, salt permeability, or membrane structural parameter when operated with the membrane skin layer facing the draw solution (PRO-mode). However, water and salt permeability increased with increasing feed or draw solution temperature, while the membrane structural parameter decreased with increasing draw solution, possibly due to changes in polymer intermolecular interactions. High ionic strength draw solutions may de-swell the CTA membrane via charge neutralization, which resulted in lower water permeability, higher salt permeability, and lower structural parameter. This observed trend was further exacerbated by the presence of divalent cations which tends to swell the polymer to a greater extent. Finally, the calculated CTA membrane\\'s structural parameter was lower and less sensitive to external factors when operated in PRO-mode, but highly sensitive to the same factors when the skin layer faced the feed solution (FO-mode), presumably due to swelling/de-swelling of the saturated porous substructure by the draw solution. This is a first attempt aimed at systematically evaluating the changes in performance of the CTA membrane due to operating conditions and solution chemistry, shedding new insight into the possible advantages and disadvantages of this material in certain applications. © 2011 Elsevier B.V.

  13. Physical chemistry of the interface between oxide and aqueous solution

    International Nuclear Information System (INIS)

    Jolivet, J.P.

    1997-01-01

    The behavior and properties of small oxide particles in aqueous suspension are dominated by the physico-chemistry of their surface. It is electrostatically charged and strongly solvated. The origin of the surface charge is discussed through the MUSIC model [Hiemstra 1996], allowing to estimate the acid-base behavior of surface oxygen atoms. The stability of aqueous dispersions of particles is analysed following the DLVO model, with a special attention on the hydration layers allowing the peptization of flocs. Different adsorption mechanisms of metal cations are presented in terms of coordination chemistry (outer- and inner-sphere complexes) emphasizing the coordinating ability of the surface towards metal complexes in solution. The anion adsorption is also studied in relation with some interesting consequences on spinel iron oxide nano-particles. (author)

  14. Molecular Twister: A Game for Exploring Solution Chemistry

    OpenAIRE

    Masonjones, Sawyer R.; Masonjones, Heather D.; Malone, Megan C.; Williams, Ann H.; Beemer, Margaret M.; Waggett, Rebecca J.

    2014-01-01

    pH is an essential biological concept with critical importance at various scales, from the molecular level, dealing with blood buffers, homeostasis, and proton gradients, all the way up to the ecosystem level, with soil chemistry and acid rain. However, pH is also a concept that spawns student misconceptions and misunderstanding in terms of what is happening in a solution on the atomic level. The Molecular Twister game, created for a Florida Department of Education funded professional develop...

  15. Molecular Twister: A Game for Exploring Solution Chemistry

    Directory of Open Access Journals (Sweden)

    Sawyer R. Masonjones

    2014-02-01

    Full Text Available pH is an essential biological concept with critical importance at various scales, from the molecular level, dealing with blood buffers, homeostasis, and proton gradients, all the way up to the ecosystem level, with soil chemistry and acid rain. However, pH is also a concept that spawns student misconceptions and misunderstanding in terms of what is happening in a solution on the atomic level. The Molecular Twister game, created for a Florida Department of Education funded professional development workshop for Florida high school teachers hosted at the University of Tampa  (Science Math Masters, seeks to model pH in such a way that students can visually and kinesthetically learn the concept in a few minutes. In addition, the basic design of the game pieces allow for teaching extensions to include more complex acid-base reactions. Challenge questions are provided to allow teachers to bring relevancy to the game, using examples of acid-base chemistry pulled from cases in human health and the environment.

  16. Physico-chemistry of actinides and other radioelements in solutions and at the interfaces

    International Nuclear Information System (INIS)

    2000-01-01

    This document provides the 61 papers (transparencies used during the presentations and posters) presented at the 1999 PRACTIS days, held February 17-18, 2000 in Villeneuve-les-Avignon. The content comprises 9 conferences dealing with 1)simulation of solvation, coordination and liquid-liquid extraction of rare earth and uranyl cations 2)overview on the complexation selectivity of actinides(III) and rare earths(III) by aromatic poly-nitrogenous ligands 3)detection, characterization and interaction between supramolecular aggregates of extractants: macroscopic consequences on the stability and on the macroscopic behaviour 4)chemistry of technetium in reducing medium: application to researches on radioactive waste management 5) separations by pyro-chemistry (CEA program) 6)overview on the Goethite operation 7)use of time-resolved luminescence spectroscopy to the determination of sorption sites at the interfaces 8)dissolution of uranium dioxide in an argillaceous water: results in oxidizing and reducing conditions 9)treatment and storage of radioactive wastes from weapon-grade plutonium production in Russia and other countries. A large part of the conference was devoted to poster sessions on the following topics: physico-chemistry in homogeneous solutions (22 posters), transfer kinetics of actinides and rare earths between liquid phases and separations (9 posters), physico-chemistry of the solid-solution interface (9 posters), simulation and molecular dynamics (5 posters), uranium dioxide and other oxides (1 poster), long-lived fission products (6 posters). (O.M.)

  17. Effect of surface chemistry, solution pH, and ionic strength on the removal of herbicides diuron and amitrole from water by an activated carbon fiber.

    Science.gov (United States)

    Fontecha-Cámara, M A; López-Ramón, M V; Alvarez-Merino, M A; Moreno-Castilla, C

    2007-01-30

    A study was conducted on the effects of carbon surface chemistry, solution pH, and ionic strength on the removal of diuron and amitrole from aqueous solutions by adsorption on an as-received and oxidized activated carbon fiber. Results obtained were explained by the surface characteristics of the adsorbents and the characteristics of the herbicide molecules. Under the experimental conditions used, diuron uptake was much higher than that of amitrole, despite its larger molecular dimensions, due to the lesser water solubility, greater hydrophobicity, and larger dipolar moment of diuron compared with amitrole. Uptake variations associated with differences in carbon surface oxidation, solution pH, and ionic strength were explained by corresponding changes in electrostatic, hydrophobic, and van der Waals interactions.

  18. Solution chemistry

    Energy Technology Data Exchange (ETDEWEB)

    None

    1973-07-01

    Research progress is reported on studies in heavy element chemistry. Topics considered are: synergistic complexes of plutonyl ion; water uptake in synergistic systems; formation constants of some uranyl BETA -diketone complexes; thermodynamic acid dissociation constants of BETA -diketones; thermodynamic formation constants of uranyl BETA -diketonates; thiocyanate complexes of some trivalent lanthanides and actinides; stability constants of actinide complexes using dinonyl naphthalenesulfonic acid extraction; TBP extraction of actinides; stability constants of complexes of Pu(III) with 5- sulfosalicycllc acid; and solvent extraction behavior of Pu( VII). (DHM)

  19. Ant-mediated effects on spruce litter decomposition, solution chemistry, and microbial activity

    DEFF Research Database (Denmark)

    Stadler, B.; Schramm, Andreas; Kalbitz, K.

    2006-01-01

    the effects of ants and aphid honeydew on litter solution of Norway spruce, microbial enzyme activities, and needle decomposition in a field and greenhouse experiment during summer 2003. In the field, low ant densities had relatively little effects on litter solution 30 cm away from a tree trunk...... and %N were not affected by ants or honeydew. Our results suggest that ants have a distinct and immediate effect on solution composition and microbial activity in the litter layer indicating accelerated litter decay whereas the effect of honeydew was insignificant. Keywords: Ants; Decomposition; Formica......Forest management practices often generate clear-cut patches, which may be colonized by ants not present in the same densities in mature forests. In addition to the associated changes in abiotic conditions ants can initiate processes, which do not occur in old-growth stands. Here, we analyse...

  20. Chemistry management system for nuclear power plants

    International Nuclear Information System (INIS)

    Nagasawa, Katsumi; Maeda, Katsuji

    1998-01-01

    Recently, the chemistry management in the nuclear power plants has been changing from the problem solution to the predictive diagnosis and maintenance. It is important to maintain the integrity of plant operation by an adequate chemistry control. For these reasons, many plant operation data and chemistry analysis data should be collected and treated effectively to evaluate chemistry condition of the nuclear power plants. When some indications of chemistry anomalies occur, quick and effective root cause evaluation and countermeasures should be required. The chemistry management system has been developed as to provide sophisticate chemistry management in the nuclear power plants. This paper introduces the concept and functions of the chemistry management system for the nuclear power plants. (author)

  1. The New Color of Chemistry: Green Chemistry

    Directory of Open Access Journals (Sweden)

    Zuhal GERÇEK

    2012-01-01

    Full Text Available Green chemistry which is the new application of chemistry rules provides solutions to problems that mankind is faced with climate changes, sustainable agriculture, energy, toxics, depletion of natural sources e.g. designing new chemicals and processes that production and utilization of hazardous matters. So, it is the indispensible tool for sustainable development. Current and future chemists should consider the human health and ecological issues in their professional life. In order to provide a solution for this requirement, green chemistry rules and under standings should be primarily taken in the university curriculum and at all educational levels.

  2. Complex chemistry

    International Nuclear Information System (INIS)

    Kim, Bong Gon; Kim, Jae Sang; Kim, Jin Eun; Lee, Boo Yeon

    2006-06-01

    This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.

  3. Solvent effects in chemistry

    CERN Document Server

    Buncel, Erwin

    2015-01-01

    This book introduces the concepts, theory and experimental knowledge concerning solvent effects on the rate and equilibrium of chemical reactions of all kinds.  It begins with basic thermodynamics and kinetics, building on this foundation to demonstrate how a more detailed understanding of these effects may be used to aid in determination of reaction mechanisms, and to aid in planning syntheses. Consideration is given to theoretical calculations (quantum chemistry, molecular dynamics, etc.), to statistical methods (chemometrics), and to modern day concerns such as ""green"" chemistry, where ut

  4. Effect of non-equilibrium flow chemistry and surface catalysis on surface heating to AFE

    Science.gov (United States)

    Stewart, David A.; Henline, William D.; Chen, Yih-Kanq

    1991-01-01

    The effect of nonequilibrium flow chemistry on the surface temperature distribution over the forebody heat shield on the Aeroassisted Flight Experiment (AFE) vehicle was investigated using a reacting boundary-layer code. Computations were performed by using boundary-layer-edge properties determined from global iterations between the boundary-layer code and flow field solutions from a viscous shock layer (VSL) and a full Navier-Stokes solution. Surface temperature distribution over the AFE heat shield was calculated for two flight conditions during a nominal AFE trajectory. This study indicates that the surface temperature distribution is sensitive to the nonequilibrium chemistry in the shock layer. Heating distributions over the AFE forebody calculated using nonequilibrium edge properties were similar to values calculated using the VSL program.

  5. Effect of surface chemistries and characteristics of Ti6Al4V on the Ca and P adsorption and ion dissolution in Hank's ethylene diamine tetra-acetic acid solution.

    Science.gov (United States)

    Chang, E; Lee, T M

    2002-07-01

    This study examined the influence of chemistries and surface characteristics of Ti6Al4V on the adsorption of Ca and P species and ion dissolution behavior of the material exposed in Hank's solution with 8.0 mM ethylene diamine tetra-acetic acid at 37 degrees C. The variation of chemistries of the alloy and nano-surface characteristics (chemistries of nano-surface oxides, amphoteric OH group adsorbed on oxides, and oxide thickness) was effected by surface modification and three passivation methods (34% nitric acid passivation. 400 degrees C heated in air, and aged in 100 degrees C water). X-ray photoelectron spectroscopy and Auger electron spectroscopy were used for surface analyses. The chemistries of nano-surface oxides in a range studied should not change the capability of Ca and P adsorption. Nor is the capability affected significantly by amphoteric OH group and oxide thickness. However, passivations influence the surface oxide thickness and the early stage ion dissolution rate of the alloy. The rate-limiting step of the rate can be best explained by metal-ion transport through the oxide film, rather than hydrolysis of the film. Variation of the chemistries of titanium alloy alters the electromotive force potential of the metal, thereby affecting the corrosion and ion dissolution rate.

  6. Molecular Structure of Salt Solutions: A New View of the Interface with Implications for Heterogeneous Atmospheric Chemistry

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Pavel; Tobias, D. J.

    2001-01-01

    Roč. 105, č. 43 (2001), s. 10468-10472 ISSN 1089-5647 R&D Projects: GA MŠk LN00A032 Institutional research plan: CEZ:AV0Z4040901 Keywords : air-solution interface * salt solutions * molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.379, year: 2001

  7. Adsorption of perfluoroalkyl acids by carbonaceous adsorbents: Effect of carbon surface chemistry

    International Nuclear Information System (INIS)

    Zhi, Yue; Liu, Jinxia

    2015-01-01

    Adsorption by carbonaceous sorbents is among the most feasible processes to remove perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) from drinking and ground waters. However, carbon surface chemistry, which has long been recognized essential for dictating performance of such sorbents, has never been considered for PFOS and PFOA adsorption. Thus, the role of surface chemistry was systematically investigated using sorbents with a wide range in precursor material, pore structure, and surface chemistry. Sorbent surface chemistry overwhelmed physical properties in controlling the extent of uptake. The adsorption affinity was positively correlated carbon surface basicity, suggesting that high acid neutralizing or anion exchange capacity was critical for substantial uptake of PFOS and PFOA. Carbon polarity or hydrophobicity had insignificant impact on the extent of adsorption. Synthetic polymer-based Ambersorb and activated carbon fibers were more effective than activated carbon made of natural materials in removing PFOS and PFOA from aqueous solutions. - Highlights: • Adsorption of PFOS and PFOA by ten carbonaceous adsorbents were compared. • Surface chemistry of the adsorbents controlled adsorption affinity. • Carbon surface basicity was positively correlated with the extent of PFOS and PFOA uptake. • Carbon polarity or hydrophobicity was not correlated with adsorption affinity. • Synthetic polymer-based adsorbents were more effective in removing PFOS and PFOA. - Carbon surface basicity is the primary factor that influences adsorption affinity of the carbonaceous sorbents for perfluorooctane sulfonic and carboxylic acids

  8. Effects of solution chemistry and atmosphere on leaching of alkali borosilicate glass

    International Nuclear Information System (INIS)

    Hermansson, H.P.; Christensen, H.; Clark, D.E.; Werme, L.

    1983-01-01

    The leaching behavior of two alkali-borosilicate glasses containing 9 wt % simulated fission products and 1.6 wt % uranium oxide has been studied. Samples were exposed to one of eight types of leachants including doubly distilled water, simulated ground silicate water, a brine solution, and solutions containing various concentrations of iron, aluminum or sodium maintained at either 25 0 C, 40 0 C or 90 0 C for up to 182 days. The most aggressive leachants were the solutions containing sodium (excluding brine) and simulated ground silicate water. These solutions increased the extent of leaching by a factor of 2 to 3 over that for distilled water for one of the glasses. A partially protective surface film rich in magnesium, potassium, and chlorine was formed on the glasses exposed to the brine solution. In order to evaluate the effects of atmosphere on leaching, samples were also immersed in doubly distilled water over which the relative concentrations of oxygen, nitrogen and carbon dioxide were varied. Increasing the carbon dioxide concentration from 0 to 50% resulted in a factor of 3 increase in the leaching rate

  9. Analytical chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Myeong Hu; Lee, Hu Jun; Kim, Ha Seok

    1989-02-15

    This book give explanations on analytical chemistry with ten chapters, which deal with development of analytical chemistry, the theory of error with definition and classification, sample and treatment gravimetry on general process of gravimetry in aqueous solution and non-aqueous solution, precipitation titration about precipitation reaction and types, complexometry with summary and complex compound, oxidation-reduction equilibrium on electrode potential and potentiometric titration, solvent extraction and chromatograph and experiment with basic operation for chemical experiment.

  10. Analytical chemistry

    International Nuclear Information System (INIS)

    Chae, Myeong Hu; Lee, Hu Jun; Kim, Ha Seok

    1989-02-01

    This book give explanations on analytical chemistry with ten chapters, which deal with development of analytical chemistry, the theory of error with definition and classification, sample and treatment gravimetry on general process of gravimetry in aqueous solution and non-aqueous solution, precipitation titration about precipitation reaction and types, complexometry with summary and complex compound, oxidation-reduction equilibrium on electrode potential and potentiometric titration, solvent extraction and chromatograph and experiment with basic operation for chemical experiment.

  11. General chemistry

    International Nuclear Information System (INIS)

    Kwon, Yeong Sik; Lee, Dong Seop; Ryu, Haung Ryong; Jang, Cheol Hyeon; Choi, Bong Jong; Choi, Sang Won

    1993-07-01

    The book concentrates on the latest general chemistry, which is divided int twenty-three chapters. It deals with basic conception and stoichiometry, nature of gas, structure of atoms, quantum mechanics, symbol and structure of an electron of ion and molecule, chemical thermodynamics, nature of solid, change of state and liquid, properties of solution, chemical equilibrium, solution and acid-base, equilibrium of aqueous solution, electrochemistry, chemical reaction speed, molecule spectroscopy, hydrogen, oxygen and water, metallic atom; 1A, IIA, IIIA, carbon and atom IVA, nonmetal atom and an inert gas, transition metals, lanthanons, and actinoids, nuclear properties and radioactivity, biochemistry and environment chemistry.

  12. Solution chemistry of Mo(III) and Mo(IV): Thermodynamic foundation for modeling localized corrosion

    International Nuclear Information System (INIS)

    Wang Peiming; Wilson, Leslie L.; Wesolowski, David J.; Rosenqvist, Joergen; Anderko, Andrzej

    2010-01-01

    To investigate the behavior of molybdenum dissolution products in systems that approximate localized corrosion environments, solubility of Mo(III) in equilibrium with solid MoO 2 has been determined at 80 deg. C as a function of solution acidity, chloride concentration and partial pressure of hydrogen. The measurements indicate a strong increase in solubility with acidity and chloride concentration and a weak effect of hydrogen partial pressure. The obtained results have been combined with literature data for systems containing Mo(III), Mo(IV), and Mo(VI) in solutions to develop a comprehensive thermodynamic model of aqueous molybdenum chemistry. The model is based on a previously developed framework for simulating the properties of electrolyte systems ranging from infinite dilution to solid saturation or fused salt limit. To reproduce the measurements, the model assumes the presence of a chloride complex of Mo(III) (i.e., MoCl 2+ ) and hydrolyzed species (MoOH 2+ , Mo(OH) 2 + , and Mo(OH) 3 0 ) in addition to the Mo 3+ ion. The model generally reproduces the experimental data within experimental scattering and provides a tool for predicting the phase behavior and speciation in complex, concentrated aqueous solutions. Thus, it provides a foundation for simulating the behavior of molybdenum species in localized corrosion environments.

  13. The impact of solution chemistry of electrolyte on the sorption of pentachlorophenol and phenanthrene by natural hematite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Fanfeng; He, Yan, E-mail: yhe2006@zju.edu.cn; Lian, Zhenghua; Xu, Jianming, E-mail: jmxu@zju.edu.cn

    2014-01-01

    Hematite nanoparticles (NPs) were studied as a sorbent for hydrophobic organic contaminants (OCs) under natural ambient conditions through specially designed contrasting solution chemistry of electrolyte. Ionizable pentachlorophenol (PCP) and non-ionizable phenanthrene (PHE) were selected as representative OCs. The sorption capacities of PCP and PHE were pH-dependent, and a larger amount of PCP was sorbed at pH values below its pK{sub a} (4.75). However, the PHE sorption capacity was higher at relatively high or low pHs (e.g. below 4.0 and above 10.0), possibly due to the larger available surface area of the hematite NPs, caused by the higher values of net charges and charge density. Changes in pH might thus affect the sorption of OCs by hematite NPs, through modification of the surface characteristics of the sorbent and the electronic properties of the sorbate molecules. The influence of different ionic strengths indicated that the amounts of PCP and PHE sorbed by hematite NPs decreased as a concentration function of different types of ions (e.g. Na{sup +}, K{sup +}, Mg{sup 2 +} and Ca{sup 2 +}), with the underlying mechanism possibly being due to four interactions i.e. hydrogen-bonding, competitive sorption by ions in the ambient solution, screening effects and aggregation effects. The results confirmed that the surface chemistry of hematite NPs, the chemical properties of PCP and PHE, and solution chemistry (e.g. pH and ionic strength) of the electrolyte all played an important role in PCP and PHE sorption by hematite NPs. By comparison of both sorption capacity and ecologic advantages, our results suggested that natural hematite NPs would be more competitive and efficient for PCP and PHE sorption than engineered NPs. This finding increases our knowledge regarding the environmental function of natural NPs (such as hematite NPs) for OC remediation through manipulating their interfacial behavior. - Highlights: •Hematite NPs was tested for PCP/PHE sorption under

  14. Evaluating the effects of variable water chemistry on bacterial transport during infiltration.

    Science.gov (United States)

    Zhang, Haibo; Nordin, Nahjan Amer; Olson, Mira S

    2013-07-01

    Bacterial infiltration through the subsurface has been studied experimentally under different conditions of interest and is dependent on a variety of physical, chemical and biological factors. However, most bacterial transport studies fail to adequately represent the complex processes occurring in natural systems. Bacteria are frequently detected in stormwater runoff, and may present risk of microbial contamination during stormwater recharge into groundwater. Mixing of stormwater runoff with groundwater during infiltration results in changes in local solution chemistry, which may lead to changes in both bacterial and collector surface properties and subsequent bacterial attachment rates. This study focuses on quantifying changes in bacterial transport behavior under variable solution chemistry, and on comparing the influences of chemical variability and physical variability on bacterial attachment rates. Bacterial attachment rate at the soil-water interface was predicted analytically using a combined rate equation, which varies temporally and spatially with respect to changes in solution chemistry. Two-phase Monte Carlo analysis was conducted and an overall input-output correlation coefficient was calculated to quantitatively describe the importance of physiochemical variation on the estimates of attachment rate. Among physical variables, soil particle size has the highest correlation coefficient, followed by porosity of the soil media, bacterial size and flow velocity. Among chemical variables, ionic strength has the highest correlation coefficient. A semi-reactive microbial transport model was developed within HP1 (HYDRUS1D-PHREEQC) and applied to column transport experiments with constant and variable solution chemistries. Bacterial attachment rates varied from 9.10×10(-3)min(-1) to 3.71×10(-3)min(-1) due to mixing of synthetic stormwater (SSW) with artificial groundwater (AGW), while bacterial attachment remained constant at 9.10×10(-3)min(-1) in a constant

  15. Solute-specific patterns and drivers of urban stream chemistry revealed by long-term monitoring in Baltimore, Maryland

    Science.gov (United States)

    Reisinger, A. J.; Woytowitz, E.; Majcher, E.; Rosi, E. J.; Groffman, P.

    2017-12-01

    Urban streams receive a myriad of chemical inputs from the surrounding landscape due to altered lithology (asphalt, concrete), leaky sewage infrastructure, and other human activities (road salt, fertilizer, industrial wastes, wastewater effluent), potentially leading to multiple chemical stressors occurring simultaneously. To evaluate potential drivers of water chemistry change, we used approximately 20 years of weekly water chemistry monitoring data from streams in the Baltimore Ecosystem Study (BES) to quantify trends of annual loads and flow-weighted concentrations for multiple solutes of interest, including nitrate (NO3-), phosphate (PO43-), total nitrogen (TN), total phosphorus (TP), chloride (Cl-), and sulfate (SO42-) and subsequently examined various gray and green infrastructure characteristics at the watershed scale. For example, we quantified annual volume and duration of reported sanitary sewer overflows (SSO) and cumulative storage volume and area of various best management practices (BMPs). Site- and solute-specific trends differed, but across our monitoring network we found evidence for decreasing annual export for multiple solutes. Additionally, we found that changes in gray- and green-infrastructure characteristics were related to changes in water quality at our most downstream (most urban) monitoring site. For example, annual NO3- loads increased with longer cumulative SSO duration, whereas annual PO43- and TP loads decreased with a cumulative BMP area in the watershed. Further, we used same long-term water chemistry data and multivariate analyses to investigate whether urban streams have unique water chemistry fingerprints representing the multiple chemical stressors at a given site, which could provide insight into sources and impacts of water-quality impairment. These analyses and results illustrate the major role gray and green infrastructure play in influencing water quality in urban environments, and illustrate that focusing on a variety of

  16. XI International conference Problems of solvation and complex formation in solutions, and VI Conference of young scientists Theoretical and experimental chemistry of liquid-phase systems (Krestovsky readings). Summary of reports

    International Nuclear Information System (INIS)

    2011-01-01

    The collection contains materials of plenary, sectional and poster sessions, presented at the XI International conference Problems of solvation and complex formation in solutions, and VI Conference of young scientists Theoretical and experimental chemistry of liquid-phase systems (Krestovsky readings). Theoretical questions and new experimental methods of chemistry of solutions, structure and dynamics of molecular and ion-molecular systems in solution and at the phase boundary; modern aspects of applied chemistry of solutions are discussed [ru

  17. Comparison of Chain Conformation of Poly(vinyl alcohol) in Solutions and Melts from Quantum Chemistry Based Molecular Dynamics Simulations

    Science.gov (United States)

    Jaffe, Richard; Han, Jie; Matsuda, Tsunetoshi; Yoon, Do; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    Confirmations of 2,4-dihydroxypentane (DHP), a model molecule for poly(vinyl alcohol), have been studied by quantum chemistry (QC) calculations and molecular dynamics (MD) simulations. QC calculations at the 6-311G MP2 level show the meso tt conformer to be lowest in energy followed by the racemic tg, due to intramolecular hydrogen bond between the hydroxy groups. The Dreiding force field has been modified to reproduce the QC conformer energies for DHP. MD simulations using this force field have been carried out for DHP molecules in the gas phase, melt, and CHCl3 and water solutions. Extensive intramolecular hydrogen bonding is observed for the gas phase and CHCl3 solution, but not for the melt or aqueous solution, Such a condensed phase effect due to intermolecular interactions results in a drastic change in chain conformations, in agreement with experiments.

  18. Influence of solution chemistry on the boron content in inorganic calcite grown in artificial seawater

    Science.gov (United States)

    Uchikawa, Joji; Harper, Dustin T.; Penman, Donald E.; Zachos, James C.; Zeebe, Richard E.

    2017-12-01

    The ratio of boron to calcium (B/Ca) in marine biogenic carbonates has been proposed as a proxy for properties of seawater carbonate chemistry. Applying this proxy to planktic foraminifera residing in the surface seawater largely in equilibrium with the atmosphere may provide a valuable handle on past atmospheric CO2 concentrations. However, precise controls on B/Ca in planktic foraminifera remain enigmatic because it has been shown to depend on multiple physicochemical seawater properties. To help establish a firm inorganic basis for interpreting the B/Ca records, we examined the effect of a suite of chemical parameters ([Ca2+], pH, [DIC], salinity and [PO43-]) on B/Ca in inorganic calcite precipitated in artificial seawater. These parameters were primarily varied individually while keeping all others constant, but we also tested the influence of pH and [DIC] at a constant calcite precipitation rate (R) by concurrent [Ca2+] adjustments. In the simple [Ca2+], pH and [DIC] experiments, both R and B/Ca increased with these parameters. In the pH-[Ca2+] and [DIC]-[Ca2+] experiments at constant R, on the other hand, B/Ca was invariant at different pH and decreased with [DIC], respectively. These patterns agree with the behavior of solution [BTotal/DIC] ratio such that, at a fixed [BTotal], it is independent of pH but decreases with [DIC]. Based on these results, R and [BTotal/DIC] ratio appear to be the primary controls on B/Ca in inorganic calcite, suggesting that both B(OH)4- and B(OH)3 are possibly involved in B incorporation. Moreover, B/Ca modestly increased with salinity and [PO43-]. Inorganic calcite precipitated at higher R and in the presence of oxyanions such as SO42- and PO43- in growth solutions often undergoes surface roughening due to formation of crystallographic defects, vacancies and, occasionally, amorphous/hydrous CaCO3. These non-lattice sites may provide additional space for B, particularly B(OH)3. Consequently, besides the macroscopic influence of

  19. Prediction of the effects of soil-based countermeasures on soil solution chemistry of soils contaminated with radiocesium using the hydrogeochemical code PHREEQC.

    Science.gov (United States)

    Hormann, Volker; Kirchner, Gerald

    2002-04-22

    For agriculturally used areas, which are contaminated by the debris from a nuclear accident, the use of chemical amendmends (e.g. potassium chloride and lime) is among the most common soil-based countermeasures. These countermeasures are intended to reduce the plant uptake of radionuclides (mainly 137Cs and 90Sr) by competitive inhibition by chemically similar ions. So far, the impacts of countermeasures on soil solution composition - and thus, their effectiveness - have almost exclusively been established experimentally, since they depend on mineral composition and chemical characteristics of the soil affected. In this study, which focuses on caesium contamination, the well-established code PHREEQC was used as a geochemical model to calculate the changes in the ionic compositions of soil solutions, which result from the application of potassium or ammonium in batch equilibrium experiments. The simple ion exchange model used by PHREEQC was improved by taking into account selective sorption of Cs+, NH4+ and K+ by clay minerals. Calculations were performed with three different initial soil solution compositions, corresponding to particular soil types (loam, sand, peat). For loamy and sandy soils, our calculational results agree well with experimental data reported by Nisbet (Effectiveness of soil-based countermeasures six months and one year after contamination of five diverse soil types with caesium-134 and strontium-90. Contract Report NRPB-M546, National Radiation Protection Board, Chilton, 1995.). For peat, discrepancies were found indicating that for organic soils a reliable set of exchange constants of the relevant cations still has to be determined experimentally. For cesium, however, these discrepancies almost disappeared if selective sites were assumed to be inaccessible. Additionally, results of sensitivity analyses are presented by which the influence of the main soil parameters on Cs+ concentrations in solution after soil treatment has been systematically

  20. The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

    International Nuclear Information System (INIS)

    Ebert, W.L.

    1995-03-01

    This report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume (SA/V) ratio on the corrosion behavior of borosilicate waste glasses. The SA/V ratio affects the rate of glass corrosion through the extent of dilution of corrosion products released from the glass into the leachate solution: glass corrosion products are diluted more in tests conducted at low SA/V ratios than they are in tests conducted at high SA/V ratios. Differences in the solution chemistries generated in tests conducted at different SA/V ratios then affect the observed glass corrosion behavior. Therefore, any testing parameter that affects the solution chemistry will also affect the glass corrosion rate. The results of static leach tests conducted to assess the effects of the SA/V are discussed with regard to the effects of SA/V on the solution chemistry. Test results show several remaining issues with regard to the long-term glass corrosion behavior: can the SA/V ratio be used as an accelerating parameter to characterize the advanced stages of glass corrosion relevant to long disposal times; is the alteration of the glass surface the same in tests conducted at different SA/V, and in tests conducted with monolithic and crushed glass samples; what are the effects of the SA/V and the extent of glass corrosion on the disposition of released radionuclides? These issues will bear on the prediction of the long-term performance of waste glasses during storage. The results of an experimental program conducted at ANL to address these and other remaining issues regarding the effects of SA/V on glass corrosion are described. 288 refs., 59 figs., 16 tabs

  1. The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, W.L. [Argonne National Lab., IL (United States). Chemical Technology Div.

    1995-03-01

    This report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume (SA/V) ratio on the corrosion behavior of borosilicate waste glasses. The SA/V ratio affects the rate of glass corrosion through the extent of dilution of corrosion products released from the glass into the leachate solution: glass corrosion products are diluted more in tests conducted at low SA/V ratios than they are in tests conducted at high SA/V ratios. Differences in the solution chemistries generated in tests conducted at different SA/V ratios then affect the observed glass corrosion behavior. Therefore, any testing parameter that affects the solution chemistry will also affect the glass corrosion rate. The results of static leach tests conducted to assess the effects of the SA/V are discussed with regard to the effects of SA/V on the solution chemistry. Test results show several remaining issues with regard to the long-term glass corrosion behavior: can the SA/V ratio be used as an accelerating parameter to characterize the advanced stages of glass corrosion relevant to long disposal times; is the alteration of the glass surface the same in tests conducted at different SA/V, and in tests conducted with monolithic and crushed glass samples; what are the effects of the SA/V and the extent of glass corrosion on the disposition of released radionuclides? These issues will bear on the prediction of the long-term performance of waste glasses during storage. The results of an experimental program conducted at ANL to address these and other remaining issues regarding the effects of SA/V on glass corrosion are described. 288 refs., 59 figs., 16 tabs.

  2. Radiation chemistry and the environment

    International Nuclear Information System (INIS)

    Getoff, F.

    1998-01-01

    The rather strong and many-sided pollution of the environment (atmosphere, water resources, soil) as a consequence of human activities is summarized. The solution of the arised problems by application of radiation chemistry methods and the utilization of modern environmentally ''clean'' and economical technologies, founded on electron beam processing, are mentioned. Some basic environmental problems and their solution are briefly discussed: i) Removal of CO 2 from flue gases and its radiation induced utilization. ii) Principals for degradation of aqueous pollutants by electron beam processing in the presence of ozone (synergistic effect). The radiation chemistry as a modern and manifold discipline with very broad applications can also essentially contribute in the conservation of the environment

  3. Radiation chemistry and the environment

    International Nuclear Information System (INIS)

    Getoff, Nikola

    1999-01-01

    The rather strong and many-sided pollution of the environment (atmosphere, water resources, soil) as a consequence of human activity is summarized. The solution of the arised problems by application of radiation chemistry methods and the utilization of modern environmentally 'clean' and economical technologies, founded on electron beam processing, are mentioned. Some basic environmental problems and their solution are briefly discussed. (i) Removal of CO 2 from flue gases and its radiation induced utilization. (ii) Principals for degradation of aqueous pollutants by electron beam processing in the presence of ozone (synergistic effect). The radiation chemistry as a modern and manifold discipline with very broad applications can also essentially contribute in the conservation of the environment

  4. Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion.

    Directory of Open Access Journals (Sweden)

    R Zahran

    Full Text Available Titanium implant surface etching has proven an effective method to enhance cell attachment. Despite the frequent use of hydrofluoric (HF acid, many questions remain unresolved, including the optimal etching time and its effect on surface and biological properties. The objective of this study was to investigate the effect of HF acid etching time on Ti topography, surface chemistry, wettability, and cell adhesion. These data are useful to design improved acid treatment and obtain an improved cell response. The surface topography, chemistry, dynamic wetting, and cell adhesiveness of polished Ti surfaces were evaluated after treatment with HF acid solution for 0, 2; 3, 5, 7, or 10 min, revealing a time-dependent effect of HF acid on their topography, chemistry, and wetting. Roughness and wetting increased with longer etching time except at 10 min, when roughness increased but wetness decreased. Skewness became negative after etching and kurtosis tended to 3 with longer etching time. Highest cell adhesion was achieved after 5-7 min of etching time. Wetting and cell adhesion were reduced on the highly rough surfaces obtained after 10-min etching time.

  5. Radiation chemistry

    International Nuclear Information System (INIS)

    Swallow, A.J.

    1983-01-01

    The subject is covered in chapters, entitled: introduction (defines scope of article as dealing with the chemistry of reactive species, (e.g. excess electrons, excited states, free radicals and inorganic ions in unusual valency states) as studied using radiation with radiation chemistry in its traditional sense and with biological and industrial applications); gases; water and simple inorganic systems; aqueous metallo-organic compounds and metalloproteins; small organic molecules in aqueous solution; microheterogeneous systems; non-aqueous liquids and solutions; solids; biological macromolecules; synthetic polymers. (U.K.)

  6. TUAL CHEMISTRY LABORATORY: EFFECT OF CONSTRUCTIVIST LEARNING ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Zeynep TATLI

    2012-01-01

    Full Text Available The lab applications, which were started to be applied through mid 19th century, not only provide a new point of view but also bring about a new dimension to the lessons. At early times they were used to prove theoretical knowledge but lately they turned into environments where students freely discover knowledge as an individual or in groups. The activities that have come up with the recent form of labs substantially contributed to training ideal students for constructivist approach, who research, inquire, test, seek solutions, wear scientist shoes and deeply reason about the concept of concern. However, on the present stage of our educational system, these activities cannot be included in science lessons for several reasons. At that point virtual labs emerged as an alternative solution for the problems of the instruction in science courses. Thanks to virtual labs presenting different disciplines in a flexible manner, the interaction between the teacher and the learner become 7/24 independent from time and place. This article presents a study that provides insight in the appropriateness of Virtual and real laboratory applications on constructivist learning environment using interactive virtual chemistry laboratory (VCL development was used in academic year of 2009-2010 for a six week period. The sample of this quasi-experimental study was 90 students from three different 9th grade classrooms of an Anatolian Secondary school in the center of Trabzon city. The student groups were randomly attained as one experimental and two control groups. The data collection tools of the study were; questionnaire of teaching philosophy (QTP, Semi-structured interviews and unstructured observations. The results showed that virtual chemistry laboratory software was just as effective as real chemistry laboratory and it positively affected the facilitating of constructivist learning environment. It was determined that the students in experimental group conducted the

  7. The chemistry of high temperature phosphate solutions in relation to steam generation

    International Nuclear Information System (INIS)

    Broadbent, D.; Lewis, G.G.; Wetton, E.A.M.

    1978-01-01

    The problems associated with the use of phosphate for chemical treatment of the P.W.R. secondary circuit have prompted renewed interest in the physical chemistry of these solutions. Solubility and phase studies have been carried out at 250, 300 and 350 0 C with solutions having sodium to phosphate ratios from 1.0 to above 3.0. A solid phase of ratio about 2.8 exists in equilibrium with a wide range of saturated solution compositions at each temperature. Invariant points at which three phases are in equilibrium have been identified and at the two higher temperatures a region of liquid-liquid immiscibility occurs. Phase diagrams have been constructed for each temperature from which it is possible to predict the compositional changes occurring during the isothermal evaporation process. The corrosivity of these phosphate solutions to a range of steel alloys is being studied, the results reported in the present work, however, are confined to mild steel in the temperature and phosphate composition ranges of the phase studies. The corrosion of mild steel is generally considerably less than in sodium hydroxide solutions of equivalent concentration. The dependence of corrosion rate on sodium and phosphate concentrations in not readily explicable in terms of the solubility and phase studies and it is thought that the solubility of iron in the phosphate solutions is an important rate-determining factor since several complex compounds containing sodium, phosphorus and ferrous iron are present in the corrosion films. (author)

  8. Soil solution chemistry and element fluxes in three European heathlands and their responses to warming and drought

    DEFF Research Database (Denmark)

    Schmidt, I.K.; Tietema, A.; Williams, D.

    2004-01-01

    Soil water chemistry and element budgets were studied at three northwestern European Calluna vulgaris heathland sites in Denmark (DK), The Netherlands (NL), and Wales (UK). Responses to experimental nighttime warming and early summer drought were followed during a two-year period. Soil solution...

  9. Application of solution-mineral equilibrium chemistry to solution mining of uranium ores

    International Nuclear Information System (INIS)

    Riese, A.C.; Popp, C.J.

    1979-01-01

    The tests described were undertaken to determine the extent to leach solution-rock interactions with uranium-bearing ore obtained from the Mariano Lake mine. Leach solutions of an acidic (H/sub 2/O/sub 4/-sulfuric acid) and basic (NaHCO/sub 3/-sodium bicarbonate) nature were tested, in addition to a leach solution containing potassium chloride and sulfuric acid (KCl/H/sub 2/SO/sub 4/). The latter solution was chosen in an attempt to equilibrate the aqueous phase with the rock-forming silicate minerals and minimize adverse effects such as clay formation, porosity loss, and lixiviant loss. 29 refs

  10. The response of soil solution chemistry in European forests to decreasing acid deposition

    DEFF Research Database (Denmark)

    Johnson, James; Pannatier, Elisabeth Graf; Carnicelli, Stefano

    2018-01-01

    to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Altot) and dissolved organic carbon were determined for the period 1995–2012. Plots...... with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10–20 cm, 104 plots) and subsoil (40–80 cm, 162 plots). There was a large decrease in the concentration of sulphate () in soil solution; over a 10‐year period (2000...... over the entire dataset. The response of soil solution acidity was nonuniform. At 10–20 cm, ANC increased in acid‐sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40–80 cm, ANC remained unchanged in acid‐sensitive soils (base...

  11. Effect of water chemistry on flow accelerated corrosion rate of carbon steel measured by on-line corrosion-monitoring system

    International Nuclear Information System (INIS)

    Fujiwara, K.; Domae, M.; Yoneda, K.; Inada, F.

    2010-01-01

    Flow Accelerated Corrosion (FAC) of carbon steel is one of the most important subjects in coolant systems of power plants. FAC is influenced by material, flow condition, temperature, and water chemistry. Iron and chromium solubility should be the most effective factor to determine the effect of water chemistry on the FAC. It is very important to evaluate the correlation between the solubility and the FAC rate of the carbon steel. In the present study, the effects of pH and Cr concentration of material on the FAC rate of carbon steel were evaluated by using high temperature loop equipment with on-line corrosion-monitoring system. Effect of dissolved oxygen concentration at pH 7 was also evaluated. The experimental FAC rates were compared with the calculation result, which was obtained from a FAC model developed previously by the authors' group. The tube specimens made of STPT 480 carbon steel were used for the FAC tests. The Cr concentration of STPT 480 was specially adjusted to 0.001 and 0.08 %. The inner diameters of the tubes were 1.6, 2.4, and 3.2 mm. The solutions were fed to the specimens with the flow rate of 1.5 l/min. The temperature of the solution at the specimen was controlled at 140 o C. Test solutions were demineralized water or NH 3 solutions of pH 8.0, 9.2, and 10.0. The increase in pH more than 9 decreased the FAC rates of both 0.001 and 0.08 % Cr specimens at 140 o C. Increase of the Cr concentration of the material decreased the FAC rate in the solution of pH 7.0, 8.0, 9.2, and 10.0. The FAC model reproduced well dependence of the experimental FAC behavior on water chemistry. It was confirmed that effect of pH and Cr concentration of material on the FAC rate were closely related to the solubility and diffusion of iron and chromium. (author)

  12. Chemistry of americium

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, W.W.

    1976-01-01

    Essential features of the descriptive chemistry of americium are reviewed. Chapter titles are: discovery, atomic and nuclear properties, collateral reading, production and uses, chemistry in aqueous solution, metal, alloys, and compounds, and, recovery, separation, purification. Author and subject indexes are included. (JCB)

  13. Solution and surface chemistry of the Se(IV)-Fe(0) reactions: Effect of initial solution pH.

    Science.gov (United States)

    Xia, Xuefen; Ling, Lan; Zhang, Wei-Xian

    2017-02-01

    Aspects of solution and solid-phase reactions between selenite (Se(IV)) and nanoscale zero-valent iron (nZVI) were investigated. Experimental results on the effects of initial solution pH, formation and evolution of nZVI corrosion products, and speciation of selenium in nZVI were presented. In general, the rate of Se(IV) removal decreases with increasing initial pH. The observed rate constants of Se(IV) removal decreased from 0.3530 to 0.0364 min -1 as pH increased from 4.0 to 10.0. Composition and morphology of nZVI corrosion products and selenium species were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Results confirmed that Se(IV) was reduced to Se(0) and Se(-II) by nZVI. Lower solution pH favored further reduction of Se(0) to Se(-II). Amorphous FeOOH, magnetite/maghemite (Fe 3 O 4 /γ-Fe 2 O 3 ) and ferrous hydroxide (Fe(OH) 2 ) were identified as the main corrosion products. Under alkaline conditions, the corrosion products were mainly of Fe(OH) 2 along with small amounts of Fe 3 O 4 , while nZVI in acidic solutions was oxidized to mostly Fe 3 O 4 and amorphous FeOOH. Furthermore, these corrosion products acted as intermediates for electron transfer and reactive/sorptive sites for Se(IV) adsorption and reduction, thus played a crucial role in the removal of aqueous Se(IV). Copyright © 2016. Published by Elsevier Ltd.

  14. The latest general chemistry

    International Nuclear Information System (INIS)

    Ryu, Geun Bae; Choi, Se Yeong; Kim, Chin Yeong; Yoon, Gil Jung; Lee, Eun Seok; Seo, Moon Gyu

    1995-02-01

    This book deals with the latest general chemistry, which is comprised of twenty-three chapters, the contents of this book are introduction, theory of atoms and molecule, chemical formula and a chemical reaction formula, structure of atoms, nature of atoms and the periodic table, structure of molecule and spectrum, gas, solution, solid, chemical combination, chemical reaction speed, chemical equilibrium, thermal chemistry, oxidation-reduction, electrochemistry, acid-base, complex, aquatic chemistry, air chemistry, nuclear chemistry, metal and nonmetal, organic chemistry and biochemistry. It has exercise in the end of each chapter.

  15. Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

    Science.gov (United States)

    Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

    2015-01-01

    “Clumped-isotope” thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope “clumps”). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals.We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect.Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3− and CO32−. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many

  16. Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

    Science.gov (United States)

    Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

    2015-10-01

    ;Clumped-isotope; thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope ;clumps;). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals. We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect. Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3- and CO32-. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many natural systems. The two

  17. Hitch code capabilities for modeling AVT chemistry

    International Nuclear Information System (INIS)

    Leibovitz, J.

    1985-01-01

    Several types of corrosion have damaged alloy 600 tubing in the secondary side of steam generators. The types of corrosion include wastage, denting, intergranular attack, stress corrosion, erosion-corrosion, etc. The environments which cause attack may originate from leaks of cooling water into the condensate, etc. When the contaminated feedwater is pumped into the generator, the impurities may concentrate first 200 to 400 fold in the bulk water, depending on the blowdown, and then further to saturation and dryness in heated tube support plate crevices. Characterization of local solution chemistries is the first step to predict and correct the type of corrosion that can occur. The pH is of particular importance because it is a major factor governing the rate of corrosion reactions. The pH of a solution at high temperature is not the same as the ambient temperature, since ionic dissociation constants, solubility and solubility products, activity coefficients, etc., all change with temperature. Because the high temperature chemistry of such solutions is not readily characterized experimentally, modeling techniques were developed under EPRI sponsorship to calculate the high temperature chemistry of the relevant solutions. In many cases, the effects of cooling water impurities on steam generator water chemistry with all volatile treatment (AVT), upon concentration by boiling, and in particular the resulting acid or base concentration can be calculated by a simple code, the HITCH code, which is very easy to use. The scope and applicability of the HITCH code are summarized

  18. The New Color of Chemistry: Green Chemistry

    OpenAIRE

    Zuhal GERÇEK

    2012-01-01

    Green chemistry which is the new application of chemistry rules provides solutions to problems that mankind is faced with climate changes, sustainable agriculture, energy, toxics, depletion of natural sources e.g. designing new chemicals and processes that production and utilization of hazardous matters. So, it is the indispensible tool for sustainable development. Current and future chemists should consider the human health and ecological issues in their professional life. In order to provid...

  19. Radiation chemistry in solvent extraction: FY2010 Research

    International Nuclear Information System (INIS)

    Mincher, Bruce J.; Martin, Leigh R.; Mezyk, Stephen P.

    2010-01-01

    This report summarizes work accomplished under the Fuel Cycle Research and Development (FCR and D) program in the area of radiation chemistry during FY 2010. The tasks assigned during FY 2010 included: (1) Development of techniques to measure free radical reaction kinetics in the organic phase. (2) Initiation of an alpha-radiolysis program; (3) Initiation of an effort to understand dose rate effects in radiation chemistry; (4) Continued work to characterize TALSPEAK radiation chemistry Progress made on each of these tasks is reported here. Briefly, a method was developed and used to measure the kinetics of the reactions of the NO3 radical with solvent extraction ligands in organic solution, and the method to measure OH radical reactions under the same conditions has been designed. Rate constants for the CMPO and DMDOHEMA reaction with NO3 radical in organic solution are reported. Alpha-radiolysis was initiated on samples of DMDOHEMA in alkane solution using He ion beam irradiation and 211At isotope irradiation. The samples are currently being analyzed for comparison to DMDOHEMA ?-irradiations using a custom-developed mass spectrometric method. Results are also reported for the radiolytic generation of nitrous acid, in ?-irradiated nitric acid. It is shown that the yield of nitrous acid is unaffected by an order-of-magnitude change in dose rate. Finally, recent results for TALSPEAK radiolysis are reported, summarizing the effects on solvent extraction efficiency due to HDEHP irradiation, and the stable products of lactic acid and DTPA irradiation. In addition, results representing increased scope are presented for the radiation chemistry program. These include an investigation of the effect of metal complexation on radical reaction kinetics using DTPA as an example, and the production of a manuscript reporting the mechanism of Cs-7SB radiolysis. The Cs-7SB work takes advantage of recent results from a current LDRD program to understand the fundamental chemistry of

  20. AECL research programs in chemistry

    International Nuclear Information System (INIS)

    Crocker, I.H.; Eastwood, T.A.; Smith, D.R.; Stewart, R.B.; Tomlinson, M.; Torgerson, D.F.

    1980-09-01

    Fundamental or underlying research in chemistry is being done in AECL laboratories to further the understanding of processes involved in current nuclear energy systems and maintain an awareness of progress at the frontiers of chemical research so that new advances can be turned to advantage in future AECL endeavours. The report introduces the current research topics and describes them briefly under the following headings: radiation chemistry, isotope separation, high temperature solution chemistry, fuel reprocessing chemistry, and analytical chemistry. (auth)

  1. A review of the radiation chemistry of iodine compounds in aqueous solution

    International Nuclear Information System (INIS)

    Sellers, R.M.

    1977-06-01

    Large amounts of radioactive iodine are formed in the fission of uranium in nuclear reactors. Some of this may be released to the coolant from the fuel either by diffusion through the canning material, or following the failure of a fuel pin. The iodine, which is released mainly as I 2 and methyl iodide, is transported with the coolant and, in direct cycle water cooled reactors, some is carried over with the steam to the turbines, where contamination may build up in the vicinity of steam leaks. Any assessment of the mechanism of the transport of iodine requires a knowledge of the relative amounts of the various oxidation states present, and must consider not only the thermal behaviour of iodine in water, but also the radiation chemical effects. A review is presented of the radiation chemistry of inorganic iodine compounds and methyl iodide in aqueous solutions. A number of unstable intermediates have been identified including species with iodide in valency states II, IV, VI and VIII. A considerable number of discrepancies exist in the literature data, and requirements for further work are identified. (author)

  2. Transport of E. coli D21g with runoff water under different solution chemistry conditions and surface slopes

    Science.gov (United States)

    Tracer and indicator microbe runoff experiments were conducted to investigate the influence of solution chemistry on the transport, retention, and release of Escherichia coli D21g. Experiments were conducted in a chamber (2.25 m long, 0.15 m wide, and 0.16 m high) packed with ultrapure quartz sand (...

  3. Computational chemistry

    Science.gov (United States)

    Arnold, J. O.

    1987-01-01

    With the advent of supercomputers, modern computational chemistry algorithms and codes, a powerful tool was created to help fill NASA's continuing need for information on the properties of matter in hostile or unusual environments. Computational resources provided under the National Aerodynamics Simulator (NAS) program were a cornerstone for recent advancements in this field. Properties of gases, materials, and their interactions can be determined from solutions of the governing equations. In the case of gases, for example, radiative transition probabilites per particle, bond-dissociation energies, and rates of simple chemical reactions can be determined computationally as reliably as from experiment. The data are proving to be quite valuable in providing inputs to real-gas flow simulation codes used to compute aerothermodynamic loads on NASA's aeroassist orbital transfer vehicles and a host of problems related to the National Aerospace Plane Program. Although more approximate, similar solutions can be obtained for ensembles of atoms simulating small particles of materials with and without the presence of gases. Computational chemistry has application in studying catalysis, properties of polymers, all of interest to various NASA missions, including those previously mentioned. In addition to discussing these applications of computational chemistry within NASA, the governing equations and the need for supercomputers for their solution is outlined.

  4. Green Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Collison, Melanie

    2011-05-15

    Green chemistry is the science of chemistry used in a way that will not use or create hazardous substances. Dr. Rui Resendes is working in this field at GreenCentre Canada, an offshoot of PARTEQ Innovations in Kingston, Ontario. GreenCentre's preliminary findings suggest their licensed product {sup S}witchable Solutions{sup ,} featuring 3 classes of solvents and a surfactant, may be useful in bitumen oil sands extraction.

  5. Differences in soil solution chemistry between soils amended with nanosized CuO or Cu reference materials: implications for nanotoxicity tests.

    Science.gov (United States)

    McShane, Heather V A; Sunahara, Geoffrey I; Whalen, Joann K; Hendershot, William H

    2014-07-15

    Soil toxicity tests for metal oxide nanoparticles often include micrometer-sized oxide and metal salt treatments to distinguish between toxicity from nanometer-sized particles, non-nanometer-sized particles, and dissolved ions. Test result will be confounded if each chemical form has different effects on soil solution chemistry. We report on changes in soil solution chemistry over 56 days-the duration of some standard soil toxicity tests-in three soils amended with 500 mg/kg Cu as nanometer-sized CuO (nano), micrometer-sized CuO (micrometer), or Cu(NO3)2 (salt). In the CuO-amended soils, the log Cu2+ activity was initially low (minimum -9.48) and increased with time (maximum -5.20), whereas in the salt-amended soils it was initially high (maximum -4.80) and decreased with time (minimum -6.10). The Cu2+ activity in the nano-amended soils was higher than in the micrometer-amended soils for at least the first 11 days, and lower than in the salt-amended soils for at least 28 d. The pH, and dissolved Ca and Mg concentrations in the CuO-amended soils were similar, but the salt-amended soils had lower pH for at least 14 d, and higher Ca and Mg concentrations throughout the test. Soil pretreatments such as leaching and aging prior to toxicity tests are suggested.

  6. Multiple solutions in the theory of direct current glow discharges: Effect of plasma chemistry and nonlocality, different plasma-producing gases, and 3D modelling

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P. G. C.; Benilov, M. S. [Departamento de Física, CCCEE, Universidade da Madeira, Largo do Município, 9000 Funchal (Portugal)

    2013-10-15

    The work is aimed at advancing the multiple steady-state solutions that have been found recently in the theory of direct current (DC) glow discharges. It is shown that an account of detailed plasma chemistry and non-locality of electron transport and kinetic coefficients results in an increase of the number of multiple solutions but does not change their pattern. Multiple solutions are shown to exist for discharges in argon and helium provided that discharge pressure is high enough. This result indicates that self-organization in DC glow microdischarges can be observed not only in xenon, which has been the case until recently, but also in other plasma-producing gases; a conclusion that has been confirmed by recent experiments. Existence of secondary bifurcations can explain why patterns of spots grouped in concentric rings, observed in the experiment, possess in many cases higher number of spots in outer rings than in inner ones.

  7. Radiation chemistry and its application

    International Nuclear Information System (INIS)

    Majima, Tetsuro

    2013-01-01

    Effects of radiation to human body have been seriously discussed nowadays. These are important issues for the realization of sustainable society. It should be emphasized that various reactive intermediates generated by radiation play important roles in each cases. Radiation chemical studies will provide various reaction-mechanistic aspects on these important issues. Our research group has continuously carried out reaction-mechanistic studies using radiation chemical methods. From these studies, we have obtained a variety of results on basic molecular systems, reactions, materials that are close to practical application, biological systems and so on. Reactive species are generated from the radiation reactions in solution, and can be used as one-electron oxidative and reductive reagent to give selectively radical cation and anion of solute molecules such as various organic and inorganic molecules. Therefore, the radiation chemistry has contributed significantly to chemistry in which one-electron oxidation and reduction play the important role. The kinetics of such redox processes and the following reduction play the important role. The kinetics of such redox processes and the following reactions can be studied in real time with the transition absorption measurement by the pulse radiolysis technique. Even though the target compounds cannot be oxidized and reduced in chemical or electrochemical oxidation and reduction, their one-electron redox can be performed by the electron beam radiation. Therefore, radiation chemistry is very useful technique for basic science. Moreover, application potentials of radiation chemistry are so high for various research subjects. Moreover, application potentials of radiation chemistry are so high for various research subjects

  8. Chemistry of plutonium revealed

    International Nuclear Information System (INIS)

    Connick, R.E.

    1992-01-01

    In 1941 one goal of the Manhattan Project was to unravel the chemistry of the synthetic element plutonium as rapidly as possible. In this paper the work carried out at Berkeley from the spring of 1942 to the summer of 1945 is described briefly. The aqueous chemistry of plutonium is quite remarkable. Important insights were obtained from tracer experiments, but the full complexity was not revealed until macroscopic amounts (milligrams) became available. Because processes for separation from fission products were based on aqueous solutions, such solution chemistry was emphasized, particularly precipitation and oxidation-reduction behavior. The latter turned out to be unusually intricate when it was discovered that two more oxidation states existed in aqueous solution than had previously been suspected. Further, an equilibrium was rapidly established among the four aqueous oxidation states, while at the same time any three were not in equilibrium. These and other observations made while doing a crash study of a previously unknown element are reported

  9. Water chemistry at RBMK plants: Problems and solutions

    International Nuclear Information System (INIS)

    Mamet, V.; Yurmanov, V.

    2002-01-01

    After around 15 years of operation RBMK-1000 units undergo a major refit, which includes safety system upgrading, fuel tube replacement, etc. The above upgrading has created problems for water chemistry. In particular, in late 80's in-core insertion time of the portion of control rods was reduced 10-fold thanks to a transfer from water to filming cooling of scram channels. Scram channels are cooled with inner surface water film cooling and nitrogen is injected into heads via special pipelines. Such cooling system modernization ensures fast insertion of absorber rods. The above upgrade intensified nitric acid radiolytic generation in water coolant and pH 25 value shift to acid conditions (up to 4.5). The results of corrosion tests in such conditions proved the necessity to improve water chemistry to ensure corrosion protection of scram/control rod and circuit components, especially those made out of aluminium alloy. Since 1990 the new revision of the RBMK-1000 water chemistry standard specified the new normal operational limit and action levels for possible temporary deviations of pH 25 value. RBMK plant specific measures were implemented at RBMK plants to meet the above requirements of the 1990 revision of the RBMK-1000 water chemistry standard. Clean-up systems of the above circuit were upgraded to ensure intensive absorption of nitric acid from water and pH 25 maintenance in a slightly acid area. (authors)

  10. Water chemistry at RBMK plants: Problems and solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mamet, V.; Yurmanov, V. [VNIIAES (Russian Federation)

    2002-07-01

    After around 15 years of operation RBMK-1000 units undergo a major refit, which includes safety system upgrading, fuel tube replacement, etc. The above upgrading has created problems for water chemistry. In particular, in late 80's in-core insertion time of the portion of control rods was reduced 10-fold thanks to a transfer from water to filming cooling of scram channels. Scram channels are cooled with inner surface water film cooling and nitrogen is injected into heads via special pipelines. Such cooling system modernization ensures fast insertion of absorber rods. The above upgrade intensified nitric acid radiolytic generation in water coolant and pH{sub 25} value shift to acid conditions (up to 4.5). The results of corrosion tests in such conditions proved the necessity to improve water chemistry to ensure corrosion protection of scram/control rod and circuit components, especially those made out of aluminium alloy. Since 1990 the new revision of the RBMK-1000 water chemistry standard specified the new normal operational limit and action levels for possible temporary deviations of pH{sub 25} value. RBMK plant specific measures were implemented at RBMK plants to meet the above requirements of the 1990 revision of the RBMK-1000 water chemistry standard. Clean-up systems of the above circuit were upgraded to ensure intensive absorption of nitric acid from water and pH{sub 25} maintenance in a slightly acid area. (authors)

  11. The chemistry of plutonium revealed

    International Nuclear Information System (INIS)

    Connick, R.E.

    1990-01-01

    In 1941 one goal of the Manhattan Project was to unravel the chemistry of the synthetic element plutonium as rapidly as possible. Important insights were obtained from tracer experiments, but the full complexity of plutonium chemistry was not revealed until macroscopic amounts (milligrams) became available. Because processes for separation from fission products were aqueous solution based, such solution chemistry was emphasized, particularly precipitation and oxidation-reduction behavior. The latter turned out to be unusually intricate when it was discovered that two more oxidation states existed in aqueous solution than had previously been suspected. Further, it was found that an equilibrium was rapidly established among the four aqueous oxidation states while at the same time any three were not in equilibrium. These and other observations made while doing a crash study of a previously unknown element will be reported

  12. NCAW feed chemistry: Effect of starting chemistry on melter offgas and iron redox

    International Nuclear Information System (INIS)

    Smith, P.A.; Vienna, J.D.; Merz, M.D.

    1995-03-01

    The Pacific Northwest Laboratory (PNL) Vitrification Technology Development (PVTD) program has been established to develop technology to support immobilization of selected Hanford wastes. The effort of the PVTD program is directed by the U.S. Department of Energy (DOE). This report is part of the effort and focuses on the effect of starting waste chemistry on the vitrification process. The objective of the investigation was the evaluation of the effect of starting chemistry on the cold cap behavior in the vitrification of simulated neutralized current acid waste (NCAW). In addition this investigation provides an initial laboratory investigation of the cold cap and method for evaluation of alternate reductants

  13. Radiation chemistry in solvent extraction: FY2010 Research

    Energy Technology Data Exchange (ETDEWEB)

    Bruce J. Mincher; Leigh R. Martin; Stephen P. Mezyk

    2010-09-01

    This report summarizes work accomplished under the Fuel Cycle Research and Development (FCR&D) program in the area of radiation chemistry during FY 2010. The tasks assigned during FY 2010 included: • Development of techniques to measure free radical reaction kinetics in the organic phase. • Initiation of an alpha-radiolysis program • Initiation of an effort to understand dose rate effects in radiation chemistry • Continued work to characterize TALSPEAK radiation chemistry Progress made on each of these tasks is reported here. Briefly, a method was developed and used to measure the kinetics of the reactions of the •NO3 radical with solvent extraction ligands in organic solution, and the method to measure •OH radical reactions under the same conditions has been designed. Rate constants for the CMPO and DMDOHEMA reaction with •NO3 radical in organic solution are reported. Alpha-radiolysis was initiated on samples of DMDOHEMA in alkane solution using He ion beam irradiation and 211At isotope irradiation. The samples are currently being analyzed for comparison to DMDOHEMA ?-irradiations using a custom-developed mass spectrometric method. Results are also reported for the radiolytic generation of nitrous acid, in ?-irradiated nitric acid. It is shown that the yield of nitrous acid is unaffected by an order-of-magnitude change in dose rate. Finally, recent results for TALSPEAK radiolysis are reported, summarizing the effects on solvent extraction efficiency due to HDEHP irradiation, and the stable products of lactic acid and DTPA irradiation. In addition, results representing increased scope are presented for the radiation chemistry program. These include an investigation of the effect of metal complexation on radical reaction kinetics using DTPA as an example, and the production of a manuscript reporting the mechanism of Cs-7SB radiolysis. The Cs-7SB work takes advantage of recent results from a current LDRD program to understand the fundamental chemistry

  14. Analysis of the effect of specific vocabulary instruction on high school chemistry students' knowledge and understanding

    Science.gov (United States)

    Labrosse, Peggy

    The purpose of this study was to analyze the effects of specific vocabulary instruction on high school chemistry students' knowledge and understanding. Students might be able to formally recite a definition for a term without actually having understood the meaning of the term and its connection to other terms or to related concepts. Researchers (Cassels & Johnstone, 1983; Gabel, 1999; Johnstone, 1991) have been studying the difficulty students have in learning science, particularly chemistry. Gabel (1999) suggests that, "while research into misconceptions (also known as alternative conceptions) and problem-solving has dominated the field for the past 25 years, we are no closer to a solution that would improve the teaching and learning of chemistry" (P. 549). Gabel (1999) relates the difficulty in learning chemistry to use of language. She refers to student difficulty both with words that have more than one meaning in English and with words that are used to mean one idea in chemistry and another idea in every day language. The Frayer Model, a research-based teaching strategy, is a graphic organizer which students use to create meaningful definitions for terms in context (Frayer, Frederick, & Klausmeier, 1969). It was used as the treatment---the specific vocabulary instruction---in this research study. The researcher collected and analyzed data to answer three research questions that focused on the effect of using the Frayer model (a graphic organizer) on high school students' knowledge and understanding of academic language used in chemistry. The research took place in a New England high school. Four intact chemistry classes provided the student participants; two classes were assigned to the treatment group (TG) and two classes were assigned to the control group (CG). The TG received vocabulary instruction on 14 chosen terms using the Frayer Model. The CG received traditional vocabulary instruction with no special attention to the 14 terms selected for this study

  15. Chemistry in Microfluidic Channels

    Science.gov (United States)

    Chia, Matthew C.; Sweeney, Christina M.; Odom, Teri W.

    2011-01-01

    General chemistry introduces principles such as acid-base chemistry, mixing, and precipitation that are usually demonstrated in bulk solutions. In this laboratory experiment, we describe how chemical reactions can be performed in a microfluidic channel to show advanced concepts such as laminar fluid flow and controlled precipitation. Three sets of…

  16. Effects of Sex on Intra-Individual Variance in Urinary Solutes in Stone-Formers Collected from a Single Clinical Laboratory.

    Directory of Open Access Journals (Sweden)

    Guy M L Perry

    Full Text Available Our work in a rodent model of urinary calcium suggests genetic and gender effects on increased residual variability in urine chemistries. Based on these findings, we hypothesized that sex would similarly be associated with residual variation in human urine solutes. Sex-related effects on residuals might affect the establishment of physiological baselines and error in medical assays.We tested the effects of sex on residual variation in urine chemistry by estimating coefficients of variation (CV for urinary solutes in paired sequential 24-h urines (≤72 hour interval in 6,758 females and 9,024 males aged 16-80 submitted to a clinical laboratory.Females had higher CVs than males for urinary phosphorus overall at the False Discovery Rate (P0.3. Males had higher CVs for citrate (P<0.01 from ages 16-45 and females higher CVs for citrate (P<0.01 from ages 56-80, suggesting effects of an extant oestral cycle on residual variance.Our findings indicate the effects of sex on residual variance of the excretion of urinary solutes including phosphorus and citrate; differences in CV by sex might reflect dietary lability, differences in the fidelity of reporting or genetic differentiation in renal solute consistency. Such an effect could complicate medical analysis by the addition of random error to phenotypic assays. Renal analysis might require explicit incorporation of heterogeneity among factorial effects, and for sex in particular.

  17. Underlying chemistry research for the nuclear fuel waste management program

    International Nuclear Information System (INIS)

    Torgerson, D.F.; Sagert, N.H.; Shoesmith, D.W.; Taylor, P.

    1984-04-01

    This document reviews the underlying chemistry research part of the Canadian Nuclear Fuel Waste Management Program, carried out in the Research Chemistry Branch. This research is concerned with developing the basic chemical knowledge and under-standing required in other parts of the Program. There are four areas of underlying research: Waste Form Chemistry, Solute and Solution Chemistry, Rock-Water-Waste Interactions, and Abatement and Monitoring of Gas-Phase Radionuclides

  18. Liquid flow along a solid surface reversibly alters interfacial chemistry.

    Science.gov (United States)

    Lis, Dan; Backus, Ellen H G; Hunger, Johannes; Parekh, Sapun H; Bonn, Mischa

    2014-06-06

    In nature, aqueous solutions often move collectively along solid surfaces (for example, raindrops falling on the ground and rivers flowing through riverbeds). However, the influence of such motion on water-surface interfacial chemistry is unclear. In this work, we combine surface-specific sum frequency generation spectroscopy and microfluidics to show that at immersed calcium fluoride and fused silica surfaces, flow leads to a reversible modification of the surface charge and subsequent realignment of the interfacial water molecules. Obtaining equivalent effects under static conditions requires a substantial change in bulk solution pH (up to 2 pH units), demonstrating the coupling between flow and chemistry. These marked flow-induced variations in interfacial chemistry should substantially affect our understanding and modeling of chemical processes at immersed surfaces. Copyright © 2014, American Association for the Advancement of Science.

  19. Life's Biological Chemistry: A Destiny or Destination Starting from Prebiotic Chemistry?

    Science.gov (United States)

    Krishnamurthy, Ramanarayanan

    2018-06-05

    Research into understanding the origins -and evolution- of life has long been dominated by the concept of taking clues from extant biology and extrapolating its molecules and pathways backwards in time. This approach has also guided the search for solutions to the problem of how contemporary biomolecules would have arisen directly from prebiotic chemistry on early earth. However, the continuing difficulties in finding universally convincing solutions in connecting prebiotic chemistry to biological chemistry should give us pause, and prompt us to rethink this concept of treating extant life's chemical processes as the sole end goal and, therefore, focusing only -and implicitly- on the respective extant chemical building blocks. Rather, it may be worthwhile "to set aside the goal" and begin with what would have been plausible prebiotic reaction mixtures (which may have no obvious or direct connection to life's chemical building blocks and processes) - and allow their chemistries and interactions, under different geochemical constraints, to guide and illuminate as to what processes and systems can emerge. Such a conceptual approach gives rise to the prospect that chemistry of life-as-we-know-it is not the only result (not a "destiny"), but one that has emerged among many potential possibilities (a "destination"). This postulate, in turn, could impact the way we think about chemical signatures and criteria used in the search for alternative and extraterrestrial "life". As a bonus, we may discover the chemistries and pathways naturally that led to the emergence of life as we know it. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Chemistry Division : Annual progress report of 1974

    International Nuclear Information System (INIS)

    1974-01-01

    Research and development activities (during 1974) of the Chemistry Division of the Bhabha Atomic Research Centre, Bombay, are described. Some of the activities of particular interest to nuclear science and technology are: (1) chemistry-based problems of the operating power reactors such as development of a decontaminating solution for power reactors, correlation of iodine-131 levels in the primary heat transport system of a reactor with its operation (2) release of fission gases like xenon from ceramic fuels and (3) radiation chemistry of nitrate solutions (M.G.B.)

  1. Novel bi-metallic uranyl complexes - Redox chemistry in aqueous solutions

    International Nuclear Information System (INIS)

    Yardeni, A.; Mizrahi, E.; Maimon, I.; Zilbermann, G.; Meyerstein, D.; Zehavi-cohen, A.Z.

    2014-01-01

    The synthesis of organic ligands which can accommodate two uranium atoms at different oxidation states, mixed valency being then achieved by redox chemistry at room temperature is definitely a challenge in coordination chemistry. The following complexes were synthesized and characterized by elemental analysis, NMR, MS, IR and UV-vis

  2. Effect of Marijuana Smoking on Blood Chemistry and Serum ...

    African Journals Online (AJOL)

    The effect of marijuana smoking on blood chemistry and serum biogenic amines concentrations in humans was investigated. Eighty Marijuana addicts and twenty non- marijuana smokers were used in the study. Blood chemistry and serum biogenic amines concentrations of the marijuana addicts and controls, were ...

  3. Physical chemistry and the environment

    International Nuclear Information System (INIS)

    Dunning, T.H. Jr.; Garrett, B.C.; Kolb, C.E. Jr.; Shaw, R.W.; Choppin, G.R.; Wagner, A.F.

    1994-08-01

    From the ozone hole and the greenhouse effect to plastics recycling and hazardous waste disposal, society faces a number of issues, the solutions to which require an unprecedented understanding of the properties of molecules. We are coming to realize that the environment is a coupled set of chemical systems, its dynamics determining the welfare of the biosphere and of humans in particular. These chemical systems are governed by fundamental molecular interactions, and they present chemists with an unparalleled challenge. The application of current concepts of molecular behavior and of up-to-date experimental and computational techniques can provide us with insights into the environment that are needed to mitigate past damage, to anticipate the impact of current human activity, and to avoid future insults to the environment. Environmental chemistry encompasses a number of separate, yet interlocking, areas of research. In all of these areas progress is limited by an inadequate understanding of the underlying chemical processes involved. Participation of all chemical approaches -- experimental, theoretical and computational -- and of all disciplines of chemistry -- organic, inorganic, physical, analytical and biochemistry -- will be required to provide the necessary fundamental understanding. The Symposium on ''Physical Chemistry and the Environment'' was designed to bring the many exciting and challenging physical chemistry problems involved in environmental chemistry to the attention of a larger segment of the physical chemistry community

  4. An abstraction layer for efficient memory management of tabulated chemistry and flamelet solutions

    Science.gov (United States)

    Weise, Steffen; Messig, Danny; Meyer, Bernd; Hasse, Christian

    2013-06-01

    A large number of methods for simulating reactive flows exist, some of them, for example, directly use detailed chemical kinetics or use precomputed and tabulated flame solutions. Both approaches couple the research fields computational fluid dynamics and chemistry tightly together using either an online or offline approach to solve the chemistry domain. The offline approach usually involves a method of generating databases or so-called Lookup-Tables (LUTs). As these LUTs are extended to not only contain material properties but interactions between chemistry and turbulent flow, the number of parameters and thus dimensions increases. Given a reasonable discretisation, file sizes can increase drastically. The main goal of this work is to provide methods that handle large database files efficiently. A Memory Abstraction Layer (MAL) has been developed that handles requested LUT entries efficiently by splitting the database file into several smaller blocks. It keeps the total memory usage at a minimum using thin allocation methods and compression to minimise filesystem operations. The MAL has been evaluated using three different test cases. The first rather generic one is a sequential reading operation on an LUT to evaluate the runtime behaviour as well as the memory consumption of the MAL. The second test case is a simulation of a non-premixed turbulent flame, the so-called HM1 flame, which is a well-known test case in the turbulent combustion community. The third test case is a simulation of a non-premixed laminar flame as described by McEnally in 1996 and Bennett in 2000. Using the previously developed solver 'flameletFoam' in conjunction with the MAL, memory consumption and the performance penalty introduced were studied. The total memory used while running a parallel simulation was reduced significantly while the CPU time overhead associated with the MAL remained low.

  5. Effective Chemistry Communication in Informal Environments

    Science.gov (United States)

    National Academies Press, 2016

    2016-01-01

    Chemistry plays a critical role in daily life, impacting areas such as medicine and health, consumer products, energy production, the ecosystem, and many other areas. Communicating about chemistry in informal environments has the potential to raise public interest and understanding of chemistry around the world. However, the chemistry community…

  6. Chemistry of the actinide elements. Second edition

    International Nuclear Information System (INIS)

    Katz, J.J.; Seaborg, G.T.; Morss, L.R.

    1987-01-01

    This is an exhaustive, updated discourse on the chemistry of Actinides, Volume 1 contains a systematic coverage of the elements Ac, Th, Pa, U, Np, and Pu, which constitutes Part 1 of the work. The characterization of each element is discussed in terms of its nuclear properties, occurrence, preparation, atomic and metallic properties, chemistry of specific compounds, and solution chemistry. The first part of Volume 2 follows the same format as Volume 1 but is confined to the elements Am, Cm, Bk, Cf, and Es, plus a more condensed coverage of the Transeinsteinium elements (Fm, Md, No, Lw, and 104-109). Part 2 of this volume is devoted to a discussion of the actinide elements in general, with a specific focus on electronic spectra, thermodynamic and magnetic properties, the metallic state, structural chemistry, solution kinetics, organometallic chemistry for σ- and π-bonded compounds, and some concluding remarks on the superheavy elements

  7. Radiation chemistry of the liquid state

    International Nuclear Information System (INIS)

    Buxton, G.V.

    1987-01-01

    More is known about the radiation chemistry of water than any other liquid. From a practical viewpoint out knowledge is virtually complete, and water radiolysis now provides a very convenient way of generating an enormous variety of unstable species under well-defined conditions. This facility, coupled with the techniques of pulse radiolysis, has opened up new areas in aqueous inorganic, organic, and biochemistry that cannot be readily studied by thermal or photochemical methods. This chapter is aimed, therefore, at those who wish to use radiolytic methods to generate and study unstable species in aqueous solution. The basic features of the radiation chemistry of water are described first to show how the primary radical and molecular products evolve with time and to delineate the bounds of useful experimental conditions. Next, the properties of the primary radicals are summarized, and examples are given to show how the primary radicals can be converted into secondary radicals, often of a single kind. This is an important aspect of the radiation chemistry of aqueous solutions. Lastly, the impact of our knowledge of the radiation chemistry of water on advances in general chemistry is illustrated by examples from the fields of inorganic and organic chemistry

  8. Effect of a Virtual Chemistry Laboratory on Students' Achievement

    Science.gov (United States)

    Tatli, Zeynep; Ayas, Alipasa

    2013-01-01

    It is well known that laboratory applications are of significant importance in chemistry education. However, laboratory applications have generally been neglected in recent educational environments for a variety of reasons. In order to address this gap, this study examined the effect of a virtual chemistry laboratory (VCL) on student achievement…

  9. Solution chemistry of lanthanide complexes

    International Nuclear Information System (INIS)

    Brittain, H.G.

    1979-01-01

    Intermolecular energy transfer from Tb 3+ to Eu 3+ , luminescence intensity measurements, potentiometric titrations, differential absorption spectroscopy, and spectroscopic titrations were all used to study the binding of lanthanide ions by serine and threonine. At low pH (3.0 to 6.0) the complexes are mononuclear and ligand is only weakly bound. In the pH interval of 6.0 to 8.5 stronger interaction takes place between the ligand and the metal (with possible coordination of the undissociated hydroxyl group), and self-association of complexes becomes important. Above pH 8.5, base hydrolysis of the complexes leads to highly associated species in solution and shortly above this pH an insoluble precipitate is formed. It was found that energy could be transferred from Tb 3+ to Eu 3+ more efficiently among complexes prepared from racemic ligands than in complexes made from resolved ligand, but this stereoselectivity was only observed at pH values greater than 6.5 and in solutions having a 1:10 ratio of metal-to-ligand. No stereoselectivity was found in solutions having 1:5 ratios, and this observation was explained by the existence of 1:2 metal-ligand complexes existing in solutions having the higher ratio of metal-to-ligand (only 1:1 complexes are then found at lower ratios of metal-to-ligand). (author)

  10. The chemistry of the actinide elements. Volume I

    International Nuclear Information System (INIS)

    Katz, J.J.; Seaborg, G.T.; Morss, L.R.

    1986-01-01

    The Chemistry of the Actinide Elements is a comprehensive, contemporary and authoritative exposition of the chemistry and related properties of the 5f series of elements: actinium, thorium, protactinium, uranium and the first eleven. This second edition has been completely restructured and rewritten to incorporate current research in all areas of actinide chemistry and chemical physics. The descriptions of each element include accounts of their history, separation, metallurgy, solid-state chemistry, solution chemistry, thermo-dynamics and kinetics. Additionally, separate chapters on spectroscopy, magnetochemistry, thermodynamics, solids, the metallic state, complex ions and organometallic compounds emphasize the comparative chemistry and unique properties of the actinide series of elements. Comprehensive lists of properties of all actinide compounds and ions in solution are given, and there are special sections on such topics as biochemistry, superconductivity, radioisotope safety, and waste management, as well as discussion of the transactinides and future elements

  11. Education in Environmental Chemistry: Setting the Agenda and Recommending Action

    Science.gov (United States)

    Zoller, Uri

    2005-01-01

    The effective utilization of Education in Environmental Chemistry (EEC) in addressing global and societal environmental problems requires integration between educational, technical, financial, ethical and societal considerations. An interdisciplinary approach is fundamental to efforts to achieve long-term solutions.

  12. Development of High Temperature Chemistry Measurement System for Establishment of On-Line Water Chemistry Surveillance Network in Nuclear Power Plant

    International Nuclear Information System (INIS)

    Yeon, Jei Won; Kim, Won Ho; Song, Kyu Seok; Joo, Ki Soo; Choi, Ke Chon; Ha, Yeong Keong; Ahn, Hong Joo; Im, Hee Jung; Maeng, Wan Young

    2010-07-01

    An integrated high-temperature water chemistry sensor (pH, E redox ) was developed for the establishment of the on-line water chemistry surveillance system in nuclear power plants. The basic performance of the integrated sensor was confirmed in high-temperature (280 .deg. C, 150kg/m 2 ) lithium borate solutions by using the relationship between the concentration of lithium ion and pH-E redox values. Especially, the effects of various environmental factors such as temperature, pressure, and flow rate on YSZ-based pH electrode were evaluated for ensuring the accuracy of high-temperature pH measurement. And the relationships between each water chemistry factor (pH, redox potential, electrical conductivity) were induced for enhancing the credibility of water chemistry measurement. In addition, on the basis of the evaluation of a nuclear plant design company, we suggested potential installation positions of the measurement system in a nuclear power plant

  13. Molecular Effects of Concentrated Solutes on Protein Hydration, Dynamics, and Electrostatics.

    Science.gov (United States)

    Abriata, Luciano A; Spiga, Enrico; Peraro, Matteo Dal

    2016-08-23

    Most studies of protein structure and function are performed in dilute conditions, but proteins typically experience high solute concentrations in their physiological scenarios and biotechnological applications. High solute concentrations have well-known effects on coarse protein traits like stability, diffusion, and shape, but likely also perturb other traits through finer effects pertinent at the residue and atomic levels. Here, NMR and molecular dynamics investigations on ubiquitin disclose variable interactions with concentrated solutes that lead to localized perturbations of the protein's surface, hydration, electrostatics, and dynamics, all dependent on solute size and chemical properties. Most strikingly, small polar uncharged molecules are sticky on the protein surface, whereas charged small molecules are not, but the latter still perturb the internal protein electrostatics as they diffuse nearby. Meanwhile, interactions with macromolecular crowders are favored mainly through hydrophobic, but not through polar, surface patches. All the tested small solutes strongly slow down water exchange at the protein surface, whereas macromolecular crowders do not exert such strong perturbation. Finally, molecular dynamics simulations predict that unspecific interactions slow down microsecond- to millisecond-timescale protein dynamics despite having only mild effects on pico- to nanosecond fluctuations as corroborated by NMR. We discuss our results in the light of recent advances in understanding proteins inside living cells, focusing on the physical chemistry of quinary structure and cellular organization, and we reinforce the idea that proteins should be studied in native-like media to achieve a faithful description of their function. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  14. The slow birth of green chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Amato, I.

    1993-03-12

    Mainstream chemistry is beginning to look at environmental chemistry as an important solution to environmental problems. This can include research into developing cleaner-burning liquid fuels, cleaning up oil spills, or developing better process methods which engender less pollution, as opposed to previous practices of detecting pollutants without preventing their release to begin with. This article discusses the progress of this chemistry discipline, describes some of the ongoing research, and describes the future for environmental chemistry. An impetus for future growth will be generational change, as young scientists in training are beginning to push faculities into creating programs for environmental chemistry.

  15. Effects of water chemistry on the dissolution of ZnO nanoparticles and their toxicity to Escherichia coli

    International Nuclear Information System (INIS)

    Li Mei; Lin Daohui; Zhu Lizhong

    2013-01-01

    The dissolution of ZnO nanoparticles (nano-ZnO) plays an important role in the toxicity of nano-ZnO to the aquatic organisms. The effects of water chemistry such as pH, ionic components, and dissolved organic matter (DOM) on the dissolution of nano-ZnO and its toxicity to Escherichia coli (E. coli) were investigated in synthetic and natural water samples. The results showed that the toxicity of nano-ZnO to E. coli depended on not only free Zn 2+ but also the coexisting cations which could reduce the toxicity of Zn 2+ . Increasing solution pH, HPO 4 2− , and DOM reduced the concentration of free Zn 2+ released from nano-ZnO, and thus lowered the toxicity of nano-ZnO. In addition, both Ca 2+ and Mg 2+ dramatically reduced the toxicity of Zn 2+ to E. coli. These results highlight the importance of water chemistry on the toxicity evaluation of nano-ZnO in natural waters. - Highlights: ► The effects of water chemistry on the toxicity of nano-ZnO were investigated. ► Increasing solution pH, HPO 4 2− , and DOM reduced nano-ZnO toxicity to E. coli. ► Ca 2+ and Mg 2+ could dramatically reduce the toxicity of nano-ZnO to E. coli. ► Free Zn 2+ ions and water hardness together controlled nano-ZnO toxicity in waters. - The toxicity of nano-ZnO to E. coli depended on not only free Zn 2+ but also Ca 2+ and Mg 2+ which could reduce the toxicity of Zn 2+ .

  16. Exploiting Locality in Quantum Computation for Quantum Chemistry.

    Science.gov (United States)

    McClean, Jarrod R; Babbush, Ryan; Love, Peter J; Aspuru-Guzik, Alán

    2014-12-18

    Accurate prediction of chemical and material properties from first-principles quantum chemistry is a challenging task on traditional computers. Recent developments in quantum computation offer a route toward highly accurate solutions with polynomial cost; however, this solution still carries a large overhead. In this Perspective, we aim to bring together known results about the locality of physical interactions from quantum chemistry with ideas from quantum computation. We show that the utilization of spatial locality combined with the Bravyi-Kitaev transformation offers an improvement in the scaling of known quantum algorithms for quantum chemistry and provides numerical examples to help illustrate this point. We combine these developments to improve the outlook for the future of quantum chemistry on quantum computers.

  17. Pore-water chemistry effects on the compressibility behaviour of Boom Clay

    International Nuclear Information System (INIS)

    Deng, Y.F.; Cui, Y.J.; Tang, A.M.; Nguyen, X.P.; Li, X.L.; Maarten, V.G.

    2010-01-01

    %) and the soil can be classified as plastic clay. In order to study the effects of pore-water chemistry on soil compressibility, oedometer tests were performed following a specific procedure. After installation of the soil specimen (50 mm in diameter and 20 mm high) in the oedometer cell between two dry porous stones, the vertical stress was increased in steps from 0.05 MPa to 2.4 MPa, which corresponds to the in-situ effective vertical stress of the soil cores (before flushing the pore stone). After stabilisation of the soil deformation, a back-pressure of 1 MPa was applied from the lower base of the odometer cell using a volume/pressure controller. For each soil core, one test was performed using the synthetic pore-water solution and another one using distilled water. The soil volume change during the back-pressure application was monitored, Meanwhile, the volume of liquid (synthetic pore-water solution or distilled water) passing though the soil specimen was also recorded. Each test lasted about one month and it was stopped when the volume of liquid flow through the specimen was twice the pore volume of the soil specimen. This duration is believed to be long enough to determine the hydraulic conductivity under a constant head conditions (under a pressure gradient of 1 MPa). It is noted that for the test using distilled water, the important volume of liquid flow through the soil specimen allows all the in-situ pore-water to be flushed out from the specimen. At the end of this 'flushing' stage, the back-pressure was decreased to zero and loading and unloading were performed in steps with the vertical stress ranging from 0.05 to 3.2 MPa. This test allows determination of the soil compressibility and also the hydraulic conductivity at various void ratios, in the range of relatively low stresses (up to 3.2 MPa). The result shows that the hydraulic conductivity is almost independent of the pore-water used. By contrast, the soil compressibility clearly changes

  18. Radioanalytical Chemistry for Automated Nuclear Waste Process Monitoring

    International Nuclear Information System (INIS)

    Egorov, Oleg B.; Grate, Jay W.; DeVol, Timothy A.

    2004-01-01

    This research program is directed toward rapid, sensitive, and selective determination of beta and alpha-emitting radionuclides such as 99Tc, 90Sr, and trans-uranium (TRU) elements in low activity waste (LAW) processing streams. The overall technical approach is based on automated radiochemical measurement principles, which entails integration of sample treatment and separation chemistries and radiometric detection within a single functional analytical instrument. Nuclear waste process streams are particularly challenging for rapid analytical methods due to the complex, high-ionic-strength, caustic brine sample matrix, the presence of interfering radionuclides, and the variable and uncertain speciation of the radionuclides of interest. As a result, matrix modification, speciation control, and separation chemistries are required for use in automated process analyzers. Significant knowledge gaps exist relative to the design of chemistries for such analyzers so that radionuclides can be quantitatively and rapidly separated and analyzed in solutions derived from low-activity waste processing operations. This research is addressing these knowledge gaps in the area of separation science, nuclear detection, and analytical chemistry and instrumentation. The outcome of these investigations will be the knowledge necessary to choose appropriate chemistries for sample matrix modification and analyte speciation control and chemistries for rapid and selective separation and preconcentration of target radionuclides from complex sample matrices. In addition, new approaches for quantification of alpha emitters in solution using solid-state diode detectors, as well as improved instrumentation and signal processing techniques for use with solid-state and scintillation detectors, will be developed. New knowledge of the performance of separation materials, matrix modification and speciation control chemistries, instrument configurations, and quantitative analytical approaches will

  19. The Effect of Chemistry Laboratory Activities on Students' Chemistry Perception and Laboratory Anxiety Levels

    Science.gov (United States)

    Aydogdu, Cemil

    2017-01-01

    Chemistry lesson should be supported with experiments to understand the lecture effectively. For safety laboratory environment and to prevent laboratory accidents; chemical substances' properties, working principles for chemical substances' usage should be learnt. Aim of the present study was to analyze the effect of experiments which depend on…

  20. Progress report: Chemistry and Materials Division, 1982 April 1 - June 30

    International Nuclear Information System (INIS)

    1982-08-01

    The work of the division in the areas of solid state studies, radiation chemistry, isotope separation, analytical chemistry and materials science is described. The solid state science group studied solute atom vacancy trapping in irradiated f.c.c. alloys as well as the rearrangement of atoms in solids bombarded by energetic heavy ions. In radiation chemistry, work was done on the pulse radiolysis of NO in argon. Isotope separation studies were done on fluoroform and uranium. Fuel burnup determination using 148 Nd and 139 La was investigated. Zirconium alloy studies included work on stress corrosion cracking and the Baushinger effect

  1. Modelling the response of soil and soil solution chemistry upon roofing a forest in an area with high nitrogen deposition

    Directory of Open Access Journals (Sweden)

    C. van der Salm

    1998-01-01

    Full Text Available In the Speuld forest, the Netherlands, the dynamic soil acidification model NuCSAM has been applied to a manipulation experiment in which part of the forest was roofed to control nitrogen (N and sulphur (S deposition. The roofed area was divided into two subplots watered artificially; one received ambient N and S deposition and one with pristine N and S deposition. Concentration measurements on each plots showed a high (time-dependent spatial variability. Statistical analyses of the concentrations on both subplots showed small but significant effects of the reduction in deposition on nitrate (NO3 sulphate (SO4 and aluminum (Al concentrations. The statistical significance of the effects was minimised by the large spatial variability within the plots. Despite these shortcomings, simulated concentrations were generally within the 95% confidence interval of the measurements although the effect of a reduction in N deposition on soil solution chemistry was underestimated due to a marked decline in N-uptake by the vegetation.

  2. Exploration Of `Click' Chemistry For Microelectronic Applications

    Science.gov (United States)

    Musa, Osama M.; Sridhar, Laxmisha M.

    The ‘Click’ chemistry was explored for low temperature snap cure and for possible use as an adhesion promoter in electronic applications. Several azide and alkyne resins were synthesized and their curing potential was evaluated with a special emphasis on exploring Cu(I) catalyst effect. The preliminary curing study in the absence of catalysts showed a strong dependence of cure temperatures on the electronic nature of alkynes. The cure temperatures showed a tendency to increase with decreasing electronegativity of the substituent on alkynes. The capability of Cu(I) catalysts to accelerate the ‘Click’ chemistry was demonstrated for the first time in bulk phase. Using several Cu(I) catalysts, the cure temperatures could be lowered by as much as 40-100°C compared to the control, depending on the nature of catalyst and the catalyst loading. We discovered a novel synergistic effect between Cu(I) and silver filler in lowering the cure temperatures. Using this combination, lower cure temperatures could be obtained than using either alone. Among several resins screened, one resin system has shown promise for 80°C snap-cure in which the aforementioned synergistic effect is operative. Solution phase ‘Click’ chemistry was employed for the synthesis of a hybrid triazole-epoxy resin system. This system was found to cure without added amine curative. The triazole group here serves as a linker as well as an internal adhesion promoter. To address the incompatibility and volatility issues, which arose during evaluation, a controlled oligomerization method has been developed using controlled heating of azides and alkynes in solution phase.

  3. Radioanalytical Chemistry for Automated Nuclear Waste Process Monitoring

    International Nuclear Information System (INIS)

    Egorov, Oleg B.; Grate, Jay W.; DeVol, Timothy A.

    2003-01-01

    This research program is directed toward rapid, sensitive, and selective determination of beta and alpha-emitting radionuclides such as 99Tc, 90Sr, and trans-uranium (TRU) elements in low activity waste (LAW) processing streams. The overall technical approach is based on automated radiochemical measurement principles. Nuclear waste process streams are particularly challenging for rapid analytical methods due to the complex, high- ionic-strength, caustic brine sample matrix, the presence of interfering radionuclides, and the variable and uncertain speciation of the radionuclides of interest. As a result, matrix modification, speciation control, and separation chemistries are required for use in automated process analyzers. Significant knowledge gaps exist relative to the design of chemistries for such analyzers so that radionuclides can be quantitatively and rapidly separated and analyzed in solutions derived from low-activity waste processing operations. This research is addressing these knowledge gaps in the area of separation science, nuclear detection, and analytical chemistry and instrumentation. The outcome of these investigations will be the knowledge necessary to choose appropriate chemistries for sample matrix modification and analyte speciation control and chemistries for rapid and selective separation and preconcentration of target radionuclides from complex sample matrices. In addition, new approaches for quantification of alpha emitters in solution using solid state diode detectors, as well as improved instrumentation and signal processing techniques for use with solid-state and scintillation detectors, will be developed. New knowledge of the performance of separation materials, matrix modification and speciation control chemistries, instrument configurations, and quantitative analytical approaches will provide the basis for designing effective instrumentation for radioanalytical process monitoring. Specific analytical targets include 99 Tc, 90Sr and

  4. PWR secondary water chemistry guidelines

    International Nuclear Information System (INIS)

    Bell, M.J.; Blomgren, J.C.; Fackelmann, J.M.

    1982-10-01

    Steam generators in pressurized water reactor (PWR) nuclear power plants have experienced tubing degradation by a variety of corrosion-related mechanisms which depend directly on secondary water chemistry. As a result of this experience, the Steam Generator Owners Group and EPRI have sponsored a major program to provide solutions to PWR steam generator problems. This report, PWR Secondary Water Chemistry Guidelines, in addition to presenting justification for water chemistry control parameters, discusses available analytical methods, data management and surveillance, and the management philosophy required to successfully implement the guidelines

  5. Developments and prospects of radiation chemistry

    International Nuclear Information System (INIS)

    Imamura, Masashi

    1984-01-01

    The fruitful achievement which has been obtained in the radiation chemistry laboratory of the Institute of Physical and Chemical Research during the research for twenty years from 1963 to 1983 is summarized in this review. In the section of investigation of radiation-induced chemical reaction, the new problems and their interpretation of LET effect in the case of aqueous solution of ferrous chloride and liquid organic compound, and the radiation chemistry of liquid methanol are described, and in the section of investigation of ion-radicals, low temperature rigid solution-γ-ray irradiation method including the outline of the method and the electron absorption spectra of ion-radicals and the structure are described. In the section of pulse-radiolysis method (pulsed electron beam irradiation method), the application to the investigation of dimer cations, the initial process of dimer anions and ionic polymerization, the solvation process of anion radicals, and the long distance transfer of electrons in amorphous solid are explained. In the section of research on metal porphyrin complex related to the chemical conversion of solar energy, chlorophyll-a and its dimer, and synthetic metal porphyrin complex, and in the section of research on photochemical reaction, photochemical reaction and the chemical effect on radioactive disintegration are explained. (Yoshitake, I.)

  6. Solution chemistry and separation of metal ions in leached solution

    International Nuclear Information System (INIS)

    Shibata, J.

    1991-01-01

    The method to presume a dissolved state of metal ions in an aqueous solution and the technology to separate and concentrate metal ions in a leached solution are described in this paper. It is very important for the separation of metal ions to know the dissolved state of metal ions. If we know the composition of an aqueous solution and the stability constants of metal-ligand complexes, we can calculate and estimate the concentration of each species in the solution. Then, we can decide the policy to separate and concentrate metal ions. There are several methods for separation and purification; hydroxide precipitation method, sulfide precipitation method, solvent extraction method and ion exchange resin method. Solvent extraction has been used in purification processes of copper refinery, uranium refinery, platinum metal refinery and rare earth metal refinery. Fundamental process of solvent extraction, a kind of commercial extractants, a way of determining a suitable extractant and an equipment are discussed. Finally, it will be emphasized how the separation of rare earths is improved in solvent extraction. (author) 21 figs., 8 tabs., 8 refs

  7. The Challenge of Effective Teaching of Chemistry: A Case Study

    Directory of Open Access Journals (Sweden)

    Abraham AVAA

    2011-06-01

    Full Text Available Chemistry education has been identified to be one of the major bedrock for the transformation of our national economy, and hence must be accorded adequate attention. In this study, an attempt was made in ascertaining the remote causes for the poor performances reported in recent times in chemistry at the senior secondary level of education. About 80 persons were interviewed in the course of this work ranging from ex-students, students to teachers. Teacher variables, student variables and environment-related variables were investigated and the findings showed that these all contribute greatly to the poor performances of students in science subjects and chemistry in particular. The chemistry teacher, students, parents, senior secondary school administrators, curriculum planners, and the government are therefore faced with the daunting challenge of re-awaking interest and providing enabling environment for the effective teaching of chemistry in particular and the sciences in general.

  8. Pretreatment of lignocellulosic biomass using Fenton chemistry

    Science.gov (United States)

    Pretreatment is a necessary step in “biomass to biofuel conversion” due to the recalcitrant nature of lignocellulosic biomass. White-rot fungi utilize peroxidases and hydrogen peroxide (in vivo Fenton chemistry) to degrade lignin. In an attempt to mimic this process, solution phase Fenton chemistry ...

  9. Effects of Students' Pre- and Post-Laboratory Concept Maps on Students' Attitudes toward Chemistry Laboratory in University General Chemistry

    Science.gov (United States)

    Kilic, Ziya; Kaya, Osman Nafiz; Dogan, Alev

    2004-01-01

    The purpose of this study was to investigate the effects of scientific discussions based on student-constructed pre- and post-laboratory concept maps on students' attitudes toward chemistry laboratory in the university general chemistry. As part of instruction, during the first four laboratory sessions, students were taught how to construct and…

  10. Extraction of soil solution by drainage centrifugation-effects of centrifugal force and time of centrifugation on soil moisture recovery and solute concentration in soil moisture of loess subsoils.

    Science.gov (United States)

    Fraters, Dico; Boom, Gerard J F L; Boumans, Leo J M; de Weerd, Henk; Wolters, Monique

    2017-02-01

    The solute concentration in the subsoil beneath the root zone is an important parameter for leaching assessment. Drainage centrifugation is considered a simple and straightforward method of determining soil solution chemistry. Although several studies have been carried out to determine whether this method is robust, hardly any results are available for loess subsoils. To study the effect of centrifugation conditions on soil moisture recovery and solute concentration, we sampled the subsoil (1.5-3.0 m depth) at commercial farms in the loess region of the Netherlands. The effect of time (20, 35, 60, 120 and 240 min) on recovery was studied at two levels of the relative centrifugal force (733 and 6597g). The effect of force on recovery was studied by centrifugation for 35 min at 117, 264, 733, 2932, 6597 and 14,191g. All soil moisture samples were chemically analysed. This study shows that drainage centrifugation offers a robust, reproducible and standardised way for determining solute concentrations in mobile soil moisture in silt loam subsoils. The centrifugal force, rather than centrifugation time, has a major effect on recovery. The maximum recovery for silt loams at field capacity is about 40%. Concentrations of most solutes are fairly constant with an increasing recovery, as most solutes, including nitrate, did not show a change in concentration with an increasing recovery.

  11. Effect of Surface Chemistry on the Fluorescence of Detonation Nanodiamonds.

    Science.gov (United States)

    Reineck, Philipp; Lau, Desmond W M; Wilson, Emma R; Fox, Kate; Field, Matthew R; Deeleepojananan, Cholaphan; Mochalin, Vadym N; Gibson, Brant C

    2017-11-28

    Detonation nanodiamonds (DNDs) have unique physical and chemical properties that make them invaluable in many applications. However, DNDs are generally assumed to show weak fluorescence, if any, unless chemically modified with organic molecules. We demonstrate that detonation nanodiamonds exhibit significant and excitation-wavelength-dependent fluorescence from the visible to the near-infrared spectral region above 800 nm, even without the engraftment of organic molecules to their surfaces. We show that this fluorescence depends on the surface functionality of the DND particles. The investigated functionalized DNDs, produced from the same purified DND as well as the as-received polyfunctional starting material, are hydrogen, hydroxyl, carboxyl, ethylenediamine, and octadecylamine-terminated. All DNDs are investigated in solution and on a silicon wafer substrate and compared to fluorescent high-pressure high-temperature nanodiamonds. The brightest fluorescence is observed from octadecylamine-functionalized particles and is more than 100 times brighter than the least fluorescent particles, carboxylated DNDs. The majority of photons emitted by all particle types likely originates from non-diamond carbon. However, we locally find bright and photostable fluorescence from nitrogen-vacancy centers in diamond in hydrogenated, hydroxylated, and carboxylated detonation nanodiamonds. Our results contribute to understanding the effects of surface chemistry on the fluorescence of DNDs and enable the exploration of the fluorescent properties of DNDs for applications in theranostics as nontoxic fluorescent labels, sensors, nanoscale tracers, and many others where chemically stable and brightly fluorescent nanoparticles with tailorable surface chemistry are needed.

  12. Low temperature nitrogen chemistry. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Glarborg, P.; Dam-Johansen, K.; Kristensen, P.G.; Alzueta, M.; Roejel, H.

    1997-04-01

    The results of a two tasks program on Natural Gas Reburning are reported. The work involved an experimental and theoretical study of the reburning and hybrid reburning/SNCR chemistry in the 1000-1500 K range. The interactions between hydrocarbon and nitrogen chemistry under fuel-rich conditions were investigated in order to assess the NO{sub x} reduction potential of low temperature reburning. The effect of reburn fuel(carbon monoxide, methane, acetylene, ethylene, ethane, and methane/ethane mixture), temperature, stoichiometry, reactant dilution, reaction time, and inlet NO level were studied. The results indicate a significant NO reduction potential even below 1400 K, but extrapolation to practical conditions are complicated by inadequate knowledge of the detailed chemistry as well as of the effect of mixing. The possibilities of enhancing the conversion to N{sub 2} instead of NO by adding selective reducing agents (hybrid reburning/SNCR) were evaluated. Our results indicate little synergistic effect between reburn and SNCR. The most simple configuration, where the selective reducing agent is injected together with the burnout air, is not expected to be effective, unless the N-agent is injected in form of an aqueous solution. A chemical kinetic model for reburning and reburn/SNCR is listed and can be obtained by e-mail from pgl(commerical at)kt.dtu.dk.(au) 145 refs.

  13. The Effects of Clickers and Online Homework on Students' Achievement in General Chemistry

    Science.gov (United States)

    Gebru, Misganaw T.

    2012-01-01

    Retention of an introductory general chemistry course material is vital for student success in future chemistry and chemistry-related courses. This study investigated the effects of clickers versus online homework on students' long-term content retention, examined the effectiveness of online homework versus no graded homework on…

  14. The Effect of Teacher Performance in Implementation of The 2013 Curriculum Toward Chemistry Learning Achievement

    Science.gov (United States)

    Dewi, L. P.; Djohar, A.

    2018-04-01

    This research is a study about implementation of the 2013 Curriculum on Chemistry subject. This study aims to determine the effect of teacher performance toward chemistry learning achievement. The research design involves the independent variable, namely the performance of Chemistry teacher, and the dependent variable that is Chemistry learning achievement which includes the achievement in knowledge and skill domain. The subject of this research are Chemistry teachers and High School students in Bandung City. The research data is obtained from questionnaire about teacher performance assessed by student and Chemistry learning achievement from the students’ report. Data were analyzed by using MANOVA test. The result of multivariate significance test shows that there is a significant effect of teacher performance toward Chemistry learning achievement in knowledge and skill domain with medium effect size.

  15. Effects of Temperature on Aggregation Kinetics of Graphene Oxide in Aqueous Solutions

    Science.gov (United States)

    Wang, M.; Gao, B.; Tang, D.; Sun, H.; Yin, X.; Yu, C.

    2017-12-01

    Temperature may play an important role in controlling graphene oxide (GO) stability in aqueous solutions, but it has been overlooked in the literature. In this work, laboratory experiments were conducted to determine the effects of temperature (6, 25, and 40 °C) on GO aggregation kinetics under different combinations of ionic strength, cation type, humic acid (HA) concentration by monitoring GO hydrodynamic radii and attachment efficiencies. The results showed that, without HA, temperature increase promoted GO aggregation in both monovalent (Na+ and K+) and divalent (Ca2+) solutions. This phenomenon might be caused by multiple processes including enhanced collision frequency, enhanced cation dehydration, and reduced electrostatic repulsion. The presence of HA introduced steric repulsion forces that enhanced GO stability and temperature showed different effects GO aggregation kinetics in monovalent and divalent electrolytes. In monovalent electrolytes, cold temperature diminished the steric repulsion of HA-coated GO. As a result, the fastest increasing rate of GO hydrodynamic radius and the smallest critical coagulation concentration value appeared at the lowest temperature (6 °C). Conversely, in divalent electrolyte solutions with HA, high temperate favored GO aggregation, probably because the interactions between Ca2+ and HA increased with temperature resulting in lower HA coating on GO. Findings of this work emphasized the importance of temperature as well as solution chemistry on the stability and fate of GO nanoparticles in aquatic environment.

  16. Influence of radiolytic products on the chemistry of uranium VI in brines

    International Nuclear Information System (INIS)

    Lucchini, J-F.; Reed, D.T.; Borkowski, M.; Rafalski, A.; Conca, J.

    2004-01-01

    In the near field of a salt repository of nuclear waste, ionizing radiations can strongly affect the chemistry of concentrated saline solutions. Radiolysis can locally modify the redox conditions, speciation, solubility and mobility of the actinide compounds. In the case of uranium VI, radiolytic products can not only reduce U(VI), but also react with uranium species. The net effect on the speciation of uranyl depends on the relative kinetics of the reactions and the buildup of molecular products in brine solutions. The most important molecular products in brines are expected to be hypochlorite ion, hypochlorous acid and hydrogen peroxide. Although U(VI) is expected not to be significantly affected by radiolysis, the combined effects of the major molecular radiolytic products on the chemistry of U(VI) in brines have not been experimentally established previously. (authors)

  17. Basic actinide chemistry and physics research in close cooperation with hot laboratories: ACTILAB

    International Nuclear Information System (INIS)

    Minato, K; Konashi, K; Fujii, T; Uehara, A; Nagasaki, S; Ohtori, N; Tokunaga, Y; Kambe, S

    2010-01-01

    Basic research in actinide chemistry and physics is indispensable to maintain sustainable development of innovative nuclear technology. Actinides, especially minor actinides of americium and curium, need to be handled in special facilities with containment and radiation shields. To promote and facilitate actinide research, close cooperation with the facilities and sharing of technical and scientific information must be very important and effective. A three-year-program B asic actinide chemistry and physics research in close cooperation with hot laboratories , ACTILAB, was started to form the basis of sustainable development of innovative nuclear technology. In this program, research on actinide solid-state physics, solution chemistry and solid-liquid interface chemistry is made using four main facilities in Japan in close cooperation with each other, where basic experiments with transuranium elements can be made. The 17 O-NMR measurements were performed on (Pu 0.91 Am 0.09 )O 2 to study the electronic state and the chemical behaviour of Am and Cm ions in electrolyte solutions was studied by distribution experiments.

  18. Chemistry and heat-treatment effects on mechanical and microstructural properties of heat-treated, beta-extruded Ti--6A1--6V--2Sn

    International Nuclear Information System (INIS)

    Ulitchny, M.G.; Rack, H.J.; Dawson, D.B.

    1979-04-01

    The mechanical behavior of beta-extruded Ti--6A1--6V--2Sn was examined after a variety of sub-transus heat treatments. The microstructural variations resulting from the range of heat treatments studied also were examined. A range of alloy chemistries, within commercial limits, was used to evaluate the effect of this variable on mechanical properties. The strength--toughness combinations obtained in beta-extruded Ti--6A1--6V--2Sn ranged from about 895 MPa and 82.5 MPa√m for duplex annealed material to 1200 MPa and 54.9 MPa√m for solution treated and peak aged material. Chemistry variations had less effect on mechanical properties than would have been the case with alpha--beta processing

  19. Extraction of soil solution by drainage centrifugation—effects of centrifugal force and time of centrifugation on soil moisture recovery and solute concentration in soil moisture of loess subsoils

    NARCIS (Netherlands)

    Fraters, D.; Boom, G.J.F.L.; Boumans, L.J.M.; Weerd, H. de; Wolters, M.

    2017-01-01

    The solute concentration in the subsoil beneath the root zone is an important parameter for leaching assessment. Drainage centrifugation is considered a simple and straightforward method of determining soil solution chemistry. Although several studies have been carried out to determine whether this

  20. Effect of porosity and surface chemistry on the adsorption-desorption of uranium(VI) from aqueous solution and groundwater

    International Nuclear Information System (INIS)

    Yakout, S.M.

    2016-01-01

    Rice straw-based biochars modified with different chemical regents were used as an adsorbent for uranium(VI). Effect of pyrolysis temperature and nature of modifying agent's as well as surface chemistry, surface charge, and pore structure on U(VI) removal was investigated. Amount and nature of the surface groups has, in general, more influence than its porosity on U(VI) adsorption. The adsorption was maximum for the initial pH of 5.5. Rice straw derived biochars had comparable U(VI) adsorption as compared to other adsorbents. The U(VI) removal was 90 % from groundwater. NaHCO 3 was found to be the most efficient desorbent eluent for U(VI). (author)

  1. Use of chemistry software to teach and assess model-based reaction and equation knowledge

    Directory of Open Access Journals (Sweden)

    Kevin Pyatt

    2014-12-01

    Full Text Available This study investigated the challenges students face when learning chemical reactions in a first-year chemistry course and the effectiveness of a curriculum and software implementation that was used to teach and assess student understanding of chemical reactions and equations. This study took place over a two year period in a public suburban high-school, in southwestern USA. Two advanced placement (AP chemistry classes participated, referred to here as study group A (year 1, N = 14; and study group B (year 2, N = 21. The curriculum for a first-year chemistry course (group A was revised to include instruction on reaction-types. The second year of the study involved the creation and implementation of a software solution which promoted mastery learning of reaction-types. Students in both groups benefited from the reaction-type curriculum and achieved proficiency in chemical reactions and equations.  The findings suggest there was an added learning benefit to using the reaction-type software solution. This study also found that reaction knowledge was a moderate to strong predictor of chemistry achievement. Based on regression analysis, reaction knowledge significantly predicted chemistry achievement for both groups.

  2. Department of Nuclear Physical Chemistry

    International Nuclear Information System (INIS)

    Mikulski, J.

    1994-01-01

    The research program at the Department of Nuclear Physical Chemistry of the Niewodniczanski Institute of Nuclear Physics is described. The Department consist of three laboratories. First - Laboratory of Physical Chemistry of Separation Processes on which the activity is concentrated on production and separation of neutron deficient isotopes for medical diagnostic. Recently, the main interest was in 111 In which is a promising tracer for cancer diagnostic. To increase the effectiveness of production of indium 111 In the reaction with deuterons on the enriched cadmium target was carried out instead of the previously used one with alpha particles on natural silver. In the second one - Laboratory of Chemistry and Radiochemistry - the systematic studies of physicochemical properties of transition elements in solutions are carried out. The results of the performed experiments were used for the elaboration of new rapid and selective methods for various elements. Some of these results have been applied for separation of trans actinide elements at U-400 cyclotron of JINR Dubna. The third one laboratory -Environmental Radioactivity Laboratory - conducts continuous monitoring of radioactivity contamination of atmosphere. The investigation of different radionuclides concentration in natural environment, mainly in the forest had been carried out

  3. Polish contribution to radiation chemistry

    International Nuclear Information System (INIS)

    Kroh, J.

    1989-01-01

    This article outlines the history of radiation chemistry research in Poland from 1899 to the present day, with particular reference to radiolysis studies of aqueous solutions of radioactive compounds. (UK)

  4. Green Chemistry Teaching in Higher Education: A Review of Effective Practices

    Science.gov (United States)

    Andraos, John; Dicks, Andrew P.

    2012-01-01

    This account reviews published green chemistry teaching resources in print and online literature and our experiences in teaching the subject to undergraduate students. Effective practices in lecture and laboratory are highlighted and ongoing challenges are addressed, including areas in cutting edge green chemistry research that impact its teaching…

  5. Effects of two types of medical contrast media on routine chemistry results by three automated chemistry analyzers.

    Science.gov (United States)

    Park, Yu Jin; Rim, John Hoon; Yim, Jisook; Lee, Sang-Guk; Kim, Jeong-Ho

    2017-08-01

    The use of iodinated contrast media has grown in popularity in the past two decades, but relatively little attention has been paid to the possible interferential effects of contrast media on laboratory test results. Herein, we investigate medical contrast media interference with routine chemistry results obtained by three automated chemistry analyzers. Ten levels of pooled serum were used in the study. Two types of medical contrast media [Iopamiro (iopamidol) and Omnipaque (iohexol)] were evaluated. To evaluate the dose-dependent effects of the contrast media, iopamidol and iohexol were spiked separately into aliquots of serum for final concentrations of 1.8%, 3.6%, 5.5%, 7.3%, and 9.1%. The 28 analytes included in the routine chemistry panel were measured by using Hitachi 7600, AU5800, and Cobas c702 analyzers. We calculated the delta percentage difference (DPD) between the samples and the control, and examined dose-dependent trends. When the mean DPD values were compared with the reference cut-off criteria, the only uniformly interferential effect observed for all analyzers was in total protein with iopamidol. Two additional analytes that showed trends toward interferential effects only in few analyzers and exceeded the limits of the allowable error were the serum iron and the total CO 2 . The other combinations of analyzer and contrast showed no consistent dose-dependent propensity for change in any analyte level. Our study suggests that many of the analytes included in routine chemistry results, except total protein and serum iron, are not significantly affected by iopamidol and iohexol. These results suggest that it would be beneficial to apply a flexible medical evaluation process for patients requiring both laboratory tests and imaging studies, minimizing the need for strict regulations for sequential tests. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  6. Effects of humic acid and solution chemistry on the aggregation and dispersion of carboxyl-functionalized carbon black nanoparticles

    Science.gov (United States)

    Hwang, G.; Gomez-Flores, A.; Choi, S.; Han, Y., , Dr; Kim, H.

    2017-12-01

    The influence of humic acid, ionic strength and ionic species on the aggregation and dispersion of carboxyl-functionalized carbon black nanoparticles (CB-NPs) was systemically investigated in aqueous media. The experimental conditions of stability tests were selected to the changes in the solution chemistry (0.1-10 mM NaCl and 0.01-1 mM CaCl2) and in the presence/absence of humic acid (1 and 5 mg L-1) in an aquatic environment. The CB-NPs suspension was more rapidly settled in NaCl solution than in CaCl2. Specifically, in the case of NaCl, the aggregation rate of CB-NPs increased with ionic strength. Contrary, CB-NPs dispersed in CaCl2 were insensitive to the aggregation as the ionic strength increased; that was because specific adsorption of the divalent cation Ca2+ occurred since the zeta potential of the CB-NPs is reversed to a positive charge with increasing of the ionic strength. It was confirmed that humic acid greatly influences the stability of the CB-NPs. In particular, the dispersion of CB-NPs was improved in the whole range of ionic strengths of NaCl as well as of CaCl2. To support the results, the interaction energy between CB-NPs was calculated for each condition by using the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) and modified-DLVO theories. In the presence of humic acid, the improved stability of CB-NPs is attributed to the steric repulsive force.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A3A01020766), the Ministry of Education (MOE) and National Research Foundation of Korea (NRF) through the Human Resource Training Project for Regional Innovation (2015H1C1A1035930) and Korea Energy and Mineral Resources Engineering Program (KEMREP).

  7. Promoting sustainability through green chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Kirchhoff, Mary M. [American Chemical Society, 1155 Sixteenth Street, NW, Washington, DC 20036 (United States)

    2005-06-15

    Green chemistry is an important tool in achieving sustainability. The implementation of green chemistry, the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances, is essential if the expanding global population is to enjoy an increased standard of living without having a negative impact on the health of the planet. Cleaner technologies will allow the chemical enterprise to provide society with the goods and services on which it depends in an environmentally responsible manner. Green chemistry provides solutions to such global challenges as climate change, sustainable agriculture, energy, toxics in the environment, and the depletion of natural resources. A collaborative effort by industry, academia, and government is needed to promote the adoption of the green chemistry technologies necessary to achieve a sustainable society.

  8. Application of solution-mineral equilibrium chemistry to solution mining of uranium ores

    International Nuclear Information System (INIS)

    Riese, A.C.; Propp, C.J.

    1980-01-01

    Modern methods of uranium solution mining are typically accompanied by gains and losses of mass through reagent consumption by rock-forming minerals, with subsequent formation of clay minerals, gypsum, carbonates, and iron oxyhydroxides. A systematic approach to alleviate such problems involves the application of leach solutions that are in equilibrium with the host-rock minerals but in disequilibrium with the ore-forming minerals. This partial equilibrium can be approximated by solution-composition adjustments within the systems K 2 O-Al 2 O 3 SiO 2 -H 2 O and Na 2 O 3 -Al 2 O 3 SiO 2 -H 2 O. Uranium ore containing 0.15 percent U 3 O 8 from the Gulf Mineral Resources Corporation's Mariano Lake mine, the Smith Lake district of the Grants mineral belt, was collected for investigation. Presented are a theoretical evaluation of leachate data and an experimental treatment of the ore, which contained mainly K-feldspar, plagioclase feldspar, and quartz (with lesser amounts of micas, clay minerals, and organic carbonaceous material). Small-scale (less than or equal to 1 kg) column-leaching experiments were conducted to model the results of conventional leaching operations and to provide leachate solutions that could be compared with solutions calculated to be in equilibrium with the matrix minerals. Leach solutions employed include: 1) sulfuric acid, 2) sodium bicarbonate, and 3) sulfuric acid with 1.0 molal potassium chloride. The uranium concentrations in the sodium-bicarbonate leach solution and the acid-leach solution were about a gram per liter at the termination of the tests. However, the permeability of the ore in the acid leach was greatly reduced, owing to the formation of clay minerals. Uranium solubility in the leach column stabilized with the potassium-chloride solution was calculated from leachate compositions to be limited by the solubility of carnotite

  9. Constitutional dynamic chemistry: bridge from supramolecular chemistry to adaptive chemistry.

    Science.gov (United States)

    Lehn, Jean-Marie

    2012-01-01

    Supramolecular chemistry aims at implementing highly complex chemical systems from molecular components held together by non-covalent intermolecular forces and effecting molecular recognition, catalysis and transport processes. A further step consists in the investigation of chemical systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, thus behaving as programmed chemical systems. Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their constituents. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.The merging of the features: -information and programmability, -dynamics and reversibility, -constitution and structural diversity, points to the emergence of adaptive and evolutive chemistry, towards a chemistry of complex matter.

  10. Plant species effects on soil nutrients and chemistry in arid ecological zones.

    Science.gov (United States)

    Johnson, Brittany G; Verburg, Paul S J; Arnone, John A

    2016-09-01

    The presence of vegetation strongly influences ecosystem function by controlling the distribution and transformation of nutrients across the landscape. The magnitude of vegetation effects on soil chemistry is largely dependent on the plant species and the background soil chemical properties of the site, but has not been well quantified along vegetation transects in the Great Basin. We studied the effects of plant canopy cover on soil chemistry within five different ecological zones, subalpine, montane, pinyon-juniper, sage/Mojave transition, and desert shrub, in the Great Basin of Nevada all with similar underlying geology. Although plant species differed in their effects on soil chemistry, the desert shrubs Sarcobatus vermiculatus, Atriplex spp., Coleogyne ramosissima, and Larrea tridentata typically exerted the most influence on soil chemistry, especially amounts of K(+) and total nitrogen, beneath their canopies. However, the extent to which vegetation affected soil nutrient status in any given location was not only highly dependent on the species present, and presumably the nutrient requirements and cycling patterns of the plant species, but also on the background soil characteristics (e.g., parent material, weathering rates, leaching) where plant species occurred. The results of this study indicate that the presence or absence of a plant species, especially desert shrubs, could significantly alter soil chemistry and subsequently ecosystem biogeochemistry and function.

  11. Solute-matrix and Solute-Solute Interactions during Supercritical Fluid Extraction of Sea Buckthorn Leaves

    Czech Academy of Sciences Publication Activity Database

    Sajfrtová, Marie; Sovová, Helena

    2012-01-01

    Roč. 42, SI (2012), s. 1682-1691 E-ISSN 1877-7058. [International Congress of Chemical and Process Engineering CHISA 2012 and 15th Conference PRES 2012 /20./. Prague, 25.08.2012-29.08.2012] R&D Projects: GA TA ČR TA01010578 Institutional support: RVO:67985858 Keywords : supercritical fluid extraction * sea buckthom leaves * solute-solute interaction Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  12. Advanced water chemistry management in power plants

    International Nuclear Information System (INIS)

    Regis, V.; Sigon, F.

    1995-01-01

    Advanced water management based on low external impact cycle chemistry technologies and processes, effective on-line water control and monitoring, has been verified to improve water utilization and to reduce plant liquid supply and discharge. Simulations have been performed to optimize system configurations and performances, with reference to a 4 x 320 MWe/once-through boiler/AVT/river cooled power plant, to assess the effectiveness of membrane separation technologies allowing waste water reuse, to enhance water management system design and to compare these solutions on a cost/benefit analysis. 6 refs., 3 figs., 3 tabs

  13. The complex synthesis and solid state chemistry of ceria-lanthana solid solutions prepared via a hexamethylenetetramine precipitation

    International Nuclear Information System (INIS)

    Fleming, P.G.; Holmes, J.D.; Otway, D.J.; Morris, M.A.

    2011-01-01

    Mixed oxide solid solutions are becoming ever more commercially important across a range of applications. However, their synthesis can be problematical. Here, we show that ceria-lanthana solid solutions can be readily prepared via simple precipitation using hexamethylenetetramine. However, the solution chemistry can be complex, which results in the precipitated particles having a complex structure and morphology. Great care must be taken in both the synthesis and characterisation to quantify the complexity of the product. Even very high heat treatments were not able to produce highly homogeneous materials and X-ray diffractions reveals the non-equilibrium form of particles prepared in this way. Unexpected crystal structures are revealed including a new metastable cubic La 2 O 3 phase. - Graphical abstract: The suggested mechanism for the formation of dual fluorite phase particles, where Step 1 corresponds to room temperature aging, Step 2; heating the solution to 90 deg. C, Step 3; cooling of the solution to room temperature, Step 4; calcination to 500 deg. C, Step 5; calcination to 700 deg. C and Step 6; calcination to 1300 deg. C. The terminology of e.g. La 1-x Ce x (OH) 3 is used to indicate the formation of a mixed oxy-hydroxy participate rather than a definitive assignment of stoichiometry. Similarly, La 1-y Ce y O 2 only implies a mixed solid solution. Highlights: → Mol% of prepared Ce-La oxides did not follow that of reactant mol%. → Complex reaction pathway found to be dependent on metal solution concentrations. → At certain concentrations core shell particles were found to form. → A reaction model was produced based on cationic solubility. → Report lanthana solubility higher than previously reported in CeO 2 .

  14. Effect of reactor chemistry and operating variables on fuel cladding corrosion in PWRs

    International Nuclear Information System (INIS)

    Park, Moon Ghu; Lee, Sang Hee

    1997-01-01

    As the nuclear industry extends the fuel cycle length, waterside corrosion of zircaloy cladding has become a limiting factor in PWR fuel design. Many plant chemistry factors such as, higher lithium/boron concentration in the primary coolant can influence the corrosion behavior of zircaloy cladding. The chemistry effect can be amplified in higher duty fuel, particularlywhen surface boiling occurs. Local boiling can result in increased crud deposition on fuel cladding which may induce axial power offset anomalies (AOA), recently reported in several PWR units. In this study, the effect of reactor chemistry and operating variables on Zircaloy cladding corrosion is investigated and simulation studies are performed to evaluate the optimal primary chemistry condition for extended cycle operation. (author). 8 refs., 3 tabs., 16 figs

  15. Effect of Non-Stoichiometric Solution Chemistry on Improving the Performance of Wide-Bandgap Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Kai [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yang, Mengjin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kim, Donghoe [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Li, Zhen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Reid, Obadiah G [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yue [University of Toledo; Song, Zhaoning [University of Toledo; Zhao, Dewei [University of Toledo; Wang, Changlei [University of Toledo; Li, Liwei [ENN Energy Research Institute; ENN Solar Energy Co., Ltd.; Meng, Yuan [ENN Energy Research Institute; ENN Solar Energy Co., Ltd.; Guo, Ted [ENN Energy Research Institute; ENN Solar Energy Co., Ltd.; Yan, Yanfa [University of Toledo

    2017-10-18

    A high-efficiency wide-bandgap (WBG) perovskite solar cell is critical for developing perovskite-related (e.g., all-perovskite, perovskite/Si, or perovskite/Cu(In,Ga)Se2) tandem devices. Here, we demonstrate the use of non-stoichiometric precursor chemistry with excess methylammonium halides (MAX; X = I, Br, or Cl) for preparing high-quality ~1.75-eV FA0.83Cs0.17Pb(I0.6Br0.4)3 perovskite solar cells. Among various methylammonium halides, using excess MABr in the non-stoichiometric precursor exhibits the strongest effect on improving perovskite crystallographic properties and device characteristics without affecting the perovskite composition. In contrast, using excess MAI significantly reduces the bandgap of perovskite due to the replacement of Br with I. Using 40% excess MABr, we demonstrate a single-junction WBG perovskite solar cell with stabilized efficiency of 16.4%. We further demonstrate a 20.3%-efficient 4-terminal tandem device by using a 14.7%-efficient semi-transparent WBG perovskite top cell and an 18.6%-efficient unfiltered (5.6%-efficient filtered) Si bottom cell.

  16. The Chemistry behind Special Effects in Film and Television

    Science.gov (United States)

    Short, Daniel B.; Badger, Paul D.

    2013-01-01

    The chemistry behind practical special effects in the film and television industry is discussed, along with examples of commonly used chemical demonstrations that simulate them in the laboratory. (Contains 3 figures.)

  17. A comparison of amorphous calcium carbonate crystallization in aqueous solutions of MgCl2 and MgSO4: implications for paleo-ocean chemistry

    Science.gov (United States)

    Han, Mei; Zhao, Yanyang; Zhao, Hui; Han, Zuozhen; Yan, Huaxiao; Sun, Bin; Meng, Ruirui; Zhuang, Dingxiang; Li, Dan; Liu, Binwei

    2018-04-01

    Based on the terminology of "aragonite seas" and "calcite seas", whether different Mg sources could affect the mineralogy of carbonate sediments at the same Mg/Ca ratio was explored, which was expected to provide a qualitative assessment of the chemistry of the paleo-ocean. In this work, amorphous calcium carbonate (ACC) was prepared by direct precipitation in anhydrous ethanol and used as a precursor to study crystallization processes in MgSO4 and MgCl2 solutions having different concentrations at 60 °C (reaction times 240 and 2880 min). Based on the morphology of the aragonite crystals, as well as mineral saturation indices and kinetic analysis of geochemical processes, it was found that these crystals formed with a spherulitic texture in 4 steps. First, ACC crystallized into columnar Mg calcite by nearly oriented attachment. Second, the Mg calcite changed from columnar shapes into smooth dumbbell forms. Third, the Mg calcite transformed into rough dumbbell or cauliflower-shaped aragonite forms by local dissolution and precipitation. Finally, the aragonite transformed further into spherulitic radial and irregular aggregate forms. The increase in Ca2+ in the MgSO4 solutions compared with the MgCl2 solutions indicates the fast dissolution and slow precipitation of ACC in the former solutions. The phase transition was more complete in the 0.005 M MgCl2 solution, whereas Mg calcite crystallized from the 0.005 M MgSO4 solution, indicating that Mg calcite could be formed more easily in an MgSO4 solution. Based on these findings, aragonite and Mg calcite relative to ACC could be used to provide a qualitative assessment of the chemistry of the paleo-ocean. Therefore, calcite seas relative to high-Mg calcite could reflect a low concentration MgSO4 paleo-ocean, while aragonite seas could be related to an MgCl2 or high concentration of MgSO4 paleo-ocean.

  18. Non-uniform Solute Segregation at Semi-Coherent Metal/Oxide Interfaces

    Science.gov (United States)

    Choudhury, Samrat; Aguiar, Jeffery A.; Fluss, Michael J.; Hsiung, Luke L.; Misra, Amit; Uberuaga, Blas P.

    2015-08-01

    The properties and performance of metal/oxide nanocomposites are governed by the structure and chemistry of the metal/oxide interfaces. Here we report an integrated theoretical and experimental study examining the role of interfacial structure, particularly misfit dislocations, on solute segregation at a metal/oxide interface. We find that the local oxygen environment, which varies significantly between the misfit dislocations and the coherent terraces, dictates the segregation tendency of solutes to the interface. Depending on the nature of the solute and local oxygen content, segregation to misfit dislocations can change from attraction to repulsion, revealing the complex interplay between chemistry and structure at metal/oxide interfaces. These findings indicate that the solute chemistry at misfit dislocations is controlled by the dislocation density and oxygen content. Fundamental thermodynamic concepts - the Hume-Rothery rules and the Ellingham diagram - qualitatively predict the segregation behavior of solutes to such interfaces, providing design rules for novel interfacial chemistries.

  19. Potential alteration of precipitation chemistry by epiphytic lichens

    Energy Technology Data Exchange (ETDEWEB)

    Lang, G E; Reiners, W A; Heier, R K

    1976-01-01

    Epiphytic lichen growth is abundant on the boles and branches of balsam fir trees at high elevations in New Hampshire. These lichens absorb elements needed for growth from solutions flowing over their surfaces and from direct impaction of water droplets. This study describes how epiphytic lichens and fir needles altered the chemistry of simulated rain water solutions under laboratory conditions. Experiments showed: 1) lichens absorbed ammonium and nitrate from solution; the rate of uptake increased with increasing temperature of the solution, 2) lichens lost calcium, magnesium, and hydrogen to the solution, 3) lichen thalli also initially lost potassium, but in time, net movement was reversed back into the thallus, 4) cation movement increased with increasing temperature, and 5) fir needles responded in a manner similar to that of the lichens, but the amount of change was much less. From these results it seems that epiphytic lichens have potential ecological importance in altering the chemistry of throughfall and stemflow.

  20. The response of soil solution chemistry in European forests to decreasing acid deposition.

    Science.gov (United States)

    Johnson, James; Graf Pannatier, Elisabeth; Carnicelli, Stefano; Cecchini, Guia; Clarke, Nicholas; Cools, Nathalie; Hansen, Karin; Meesenburg, Henning; Nieminen, Tiina M; Pihl-Karlsson, Gunilla; Titeux, Hugues; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Waldner, Peter; Jonard, Mathieu

    2018-03-31

    Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosystems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al tot ) and dissolved organic carbon were determined for the period 1995-2012. Plots with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10-20 cm, 104 plots) and subsoil (40-80 cm, 162 plots). There was a large decrease in the concentration of sulphate (SO42-) in soil solution; over a 10-year period (2000-2010), SO42- decreased by 52% at 10-20 cm and 40% at 40-80 cm. Nitrate was unchanged at 10-20 cm but decreased at 40-80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca 2+  + Mg 2+  + K + ) and Al tot over the entire dataset. The response of soil solution acidity was nonuniform. At 10-20 cm, ANC increased in acid-sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40-80 cm, ANC remained unchanged in acid-sensitive soils (base saturation ≤20%, pHCaCl2 ≤ 4.5) and decreased in better-buffered soils (base saturation >20%, pHCaCl2 > 4.5). In addition, the molar ratio of Bc to Al tot either did not change or decreased. The results suggest a long-time lag between emission abatement and changes in soil solution acidity and underline the importance of long-term monitoring in evaluating ecosystem response to decreases in deposition. © 2018 John Wiley & Sons

  1. A Wet Chemistry Laboratory Cell

    Science.gov (United States)

    2008-01-01

    This picture of NASA's Phoenix Mars Lander's Wet Chemistry Laboratory (WCL) cell is labeled with components responsible for mixing Martian soil with water from Earth, adding chemicals and measuring the solution chemistry. WCL is part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument suite on board the Phoenix lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  2. Theoretical chemistry advances and perspectives

    CERN Document Server

    Eyring, Henry

    1980-01-01

    Theoretical Chemistry: Advances and Perspectives, Volume 5 covers articles concerning all aspects of theoretical chemistry. The book discusses the mean spherical approximation for simple electrolyte solutions; the representation of lattice sums as Mellin-transformed products of theta functions; and the evaluation of two-dimensional lattice sums by number theoretic means. The text also describes an application of contour integration; a lattice model of quantum fluid; as well as the computational aspects of chemical equilibrium in complex systems. Chemists and physicists will find the book usef

  3. Fuel Chemistry Division: progress report for 1985

    International Nuclear Information System (INIS)

    1988-01-01

    Fuel Chemistry Division was formed in May 1985 to give a larger emphasis on the research and development in chemistry of the nuclear fuel cycle. The areas of research in Fuel Chemistry Division are fuel development and its chemical quality control, understanding of the fuel behaviour and post irradiation examinations, chemistry of reprocessing and waste management processes as also the basic aspects of actinide and relevant fission product elements. This report summarises the work by the staff of the Division during 1985 and also some work from the previous periods which was not reported in the progress reports of the Radiochemistry Division. The work related to the FBTR fuel was one of the highlights during this period. In the area of process chemistry useful work has been carried out for processing of plutonium bearing solutions. In the area of mass spectrometry, the determination of trace constituents by spark source mass spectrometry has been a major area of research. Significant progress has also been made in the use of alpha spectromet ry techniques for the determination of plutonium in dissolver solution and other samples. The technology of plutonium utilisation is quite complex and the Division would continue to look into the chemical aspects of this technology and provide the necessary base for future developments in this area. (author)

  4. An innovation in the teaching of greenhouse effect in chemistry ...

    African Journals Online (AJOL)

    The teaching of greenhouse effect is difficult and is done in abstraction. This paper suggests a new instrument, called Improvised Greenhouse Effect Apparatus (IGHA) for the teaching of Greenhouse effect. 100 students were randomly selected from the Department of Chemistry, Cross River State College of Education, ...

  5. The effect of high school chemistry instruction on students' academic self-concept

    Science.gov (United States)

    Morgan, Peter Wallace

    The purpose of this study was to investigate the effect of extended instruction in high school chemistry on the academic self-concept of students and determine what parts of the learning experience need to be addressed to make the interaction a more positive one. Fifty-seven students from three metropolitan public schools, who were enrolled in college preparatory chemistry classes, were asked to complete a written instrument, before and after extended chemistry instruction, that measures academic self-concept. Twenty-one of the students who took part in the written task volunteered to answer some in-depth interview questions concerning their academic self-concept and its relationship to chemistry instruction. Student responses, instrument scores, and student chemistry grades were analyzed for a variety of chemistry learning--academic self-concept connections and interactions. Results showed that there was a positive interaction for less than half of the students involved in the interview sessions. The results from the written instrument showed similar findings. Comparing chemistry grades and academic self-concept revealed an uncertain connection between the two, especially for students with strong academic self-concepts. Students felt that the laboratory experience was often disconnected from the remainder of chemistry instruction and recommended that the laboratory experience be integrated with classroom work. Students also expressed concerns regarding the volume of algorithmic mathematical calculations associated with college preparatory chemistry instruction. Results of this study suggest that secondary chemistry instruction must become more aware of the affective domain of learning and develop a mindful awareness of its connection to the cognitive domain if chemistry teaching and learning is going to better facilitate the intellectual growth of secondary students.

  6. Understanding "Green Chemistry" and "Sustainability": An Example of Problem-Based Learning (PBL)

    Science.gov (United States)

    Günter, Tugçe; Akkuzu, Nalan; Alpat, Senol

    2017-01-01

    Background: This study uses problem-based learning (PBL) to ensure that students comprehend the significance of green chemistry better by experiencing the stages of identifying the problem, developing hypotheses, and providing solutions within the problem-solving process. Purpose: The aim of this study is to research the effect of PBL implemented…

  7. Assessment of a sequential extraction protocol by examining solution chemistry and mineralogical evolution

    Science.gov (United States)

    Maubec, Nicolas; Pauwels, Hélène; Noël, Hervé; Bourrat, Xavier

    2015-04-01

    of them are able to leach several solid phases. In this context, the aim of the present study is to investigate the effectiveness and the selectivity of different reagents for metal extraction from target geochemical fraction. It is based on solid analyses with the use of X-ray diffraction and a scanning electron microscopy (SEM) coupled to a microRaman spectrometer in conjunction with chemical analyses of extracting solutions at each step. This methodology provides the opportunity to assess more accurately the effect of each reagent. The study focuses on extraction of Cu and Zn from sediment samples collected at two sites from river banks and characterized by presence of Quartz, Feldspar K, Micas, Kaolinite but with differences regarding accessory phases (pyrite, organic matter, iron oxy- hydroxide, calcite). The interaction of the samples with eight different reagents was assessed and compared (Ca(NO3)2 and CaCl2 for the exchangeable fraction; buffered solutions of sodium acetate/acetic acid at pH = 5.5 and pH = 5 for the acido-soluble fraction; hydroxylamine hydrochloride and a solution of ammonium oxalate/oxalic acid for reducible fraction; hydrogen peroxide and sodium hypochlorite for the oxidizable fraction. In-depth characterization of solid residue at each step allowed proposing the best protocol for both metals. Anderson, P., Davidson, C. M., Duncan, A. L., Littlejohn, D., Ure, A. M., and Garden, L. M. (2000). Column leaching and sorption experiments to assess the mobility of potentially toxic elements in industrially contaminated land. Journal of Environmental Monitoring, 2. Arey, J. S., Seaman, J. C., and Bertsch, P. M. (1999). Immobilization of uranium in contaminated sediments by hydroxyapatite addition. Environmental Science & Technology, 33, 337-342. Brannon, J. M., and Patrick, W. H. (1987). Fixation, transformation, and mobilization of arsenic in sediments.Environmental Science & Technology, 21, 450-459. Cornu, S., and Clozel, B. (2000). Extractions

  8. Studies on the radiation chemistry of biomolecules in aqueous solution with specific objective of minimizing their radiolytic degradation. Coordinated programme for Asia and the Pacific Region on radiation sterilization practices significant to local medical supplies and conditions

    International Nuclear Information System (INIS)

    Narayana Rao, K.

    1979-01-01

    As part of a study of radiolytic degradation of pharmaceuticals during radiosterilization, the basic radiation chemistry of the B-group vitamins, nicotinamide, pyridoxin, riboflavin and thiamine, and the reaction of hydrogen peroxide with these same materials has been investigated. The various aspects studied were - radiolysis under controlled conditions, effects of phase, temperature, pH and nature and concentration of additives. Some of the conclusions are: 1) with oxygen saturated aqueous solutions containing glucose, the radiolytic degradation of the vitamins is reduced: 2) results a similar for N 2 O saturated aqueous solutions; 3) in glucose-containing solutions, the protective effect is considerably modified at higher temperatures; and 4) irradiation of air-saturated aqueous solutions in the frozen state leads to reduced decomposition. It is concluded that in the presence of oxygen, in frozen matrices at low temperature, it appears possible to reduce the radiolytic breakdown of vitamins to low levels

  9. Effects of solution chemistry on arsenic(V) removal by low-cost adsorbents.

    Science.gov (United States)

    Wang, Yuru; Tsang, Daniel C W

    2013-11-01

    Natural and anthropogenic arsenic (As) contamination of water sources pose serious health concerns, especially for small communities in rural areas. This study assessed the applicability of three industrial byproducts (coal fly ash, lignite, and green waste compost) as the low-cost adsorbents for As(V) removal under various field-relevant conditions (dissolved oxygen, As(V)/Fe ratio, solution pH, and presence of competing species). The physico-chemical properties of the adsorbents were characterized by XRD, XRF, FT-IR, and NMR analysis. Batch experiments demonstrated that coal fly ash could provide effective As(V) removal (82.1%-95%) because it contained high content of amorphous iron/aluminium hydroxides for As(V) adsorption and dissolvable calcium minerals for calcium arsenate precipitation. However, the addition of lignite and green waste compost was found unfavourable since they hindered the As(V) removal by 10%-42% possibly due to dissolution of organic matter and ternary arsenate-iron-organic matter complexes. On the other hand, higher concentrations of dissolved iron (comparing As(V)/Fe ratios of 1:1 and 1:10) and dissolved oxygen (comparing 0.2 and 6 mg/L) only marginally enhanced the As(V) removal at pH 6 and 8. Thus, addition of dissolved iron, water aeration, or pH adjustment became unnecessary because coal fly ash was able to provide effective As(V) removal under the natural range of geochemical conditions. Moreover, the presence of low levels of background competing (0.8 or 8 mg/L of humic acid, phosphate, and silicate) imposed little influence on As(V) removal, possibly because the high adsorption capacity of coal fly ash was far from exhaustion. These results suggested that coal fly ash was a potentially promising adsorbent that warranted further investigation.

  10. The Effect of Math SAT on Women's Chemistry Competency Beliefs

    Science.gov (United States)

    Vincent-Ruz, Paulette; Binning, Kevin; Schunn, Christian D.; Grabowski, Joe

    2018-01-01

    In chemistry, lack of academic preparation and math ability have been offered as explanations as to why women seem to enroll, perform, and graduate at lower levels than men. In this paper, we explore the alternative possibility that the gender gap in chemistry instead originates from differential gender effects of academic factors on students'…

  11. Adsorption of dyes by ACs prepared from waste tyre reinforcing fibre. Effect of texture, surface chemistry and pH.

    Science.gov (United States)

    Acevedo, Beatriz; Rocha, Raquel P; Pereira, Manuel F R; Figueiredo, José L; Barriocanal, Carmen

    2015-12-01

    This paper compares the importance of the texture and surface chemistry of waste tyre activated carbons in the adsorption of commercial dyes. The adsorption of two commercial dyes, Basic Astrazon Yellow 7GLL and Reactive Rifafix Red 3BN on activated carbons made up of reinforcing fibres from tyre waste and low-rank bituminous coal was studied. The surface chemistry of activated carbons was modified by means of HCl-HNO3 treatment in order to increase the number of functional groups. Moreover, the influence of the pH on the process was also studied, this factor being of great importance due to the amphoteric characteristics of activated carbons. The activated carbons made with reinforcing fibre and coal had the highest SBET, but the reinforcing fibre activated carbon samples had the highest mesopore volume. The texture of the activated carbons was not modified upon acid oxidation treatment, unlike their surface chemistry which underwent considerable modification. The activated carbons made with a mixture of reinforcing fibre and coal experienced the largest degree of oxidation, and so had more acid surface groups. The adsorption of reactive dye was governed by the mesoporous volume, whilst surface chemistry played only a secondary role. However, the surface chemistry of the activated carbons and dispersive interactions played a key role in the adsorption of the basic dye. The adsorption of the reactive dye was more favored in a solution of pH 2, whereas the basic dye was adsorbed more easily in a solution of pH 12. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. A Thematic Review of Studies into the Effectiveness of Context-Based Chemistry Curricula

    Science.gov (United States)

    Ültay, Neslihan; Çalık, Muammer

    2012-12-01

    Context-based chemistry education aims at making connections between real life and the scientific content of chemistry courses. The purpose of this study was to evaluate context-based chemistry studies. In looking for the context-based chemistry studies, the authors entered the keywords `context-based', `contextual learning' and `chemistry education' in well-known databases (i.e. Academic Search Complete, Education Research Complete, ERIC, Springer LINK Contemporary). Further, in case the computer search by key words may have missed a rather substantial part of the important literature in the area, the authors also conducted a hand search of the related journals. To present a detailed thematic review of context-based chemistry studies, a matrix was used to summarize the findings by focusing on insights derived from the related studies. The matrix incorporates the following themes: needs, aims, methodologies, general knowledge claims, and implications for teaching and learning, implications for curriculum development and suggestions for future research. The general knowledge claims investigated in this paper were: (a) positive effects of the context-based chemistry studies; (b) caveats, both are examined in terms of students' attitudes and students' understanding/cognition. Implications were investigated for practice in context- based chemistry studies, for future research in context- based chemistry studies, and for curriculum developers in context- based chemistry studies. Teachers of context-based courses claimed that the application of the context-based learning approach in chemistry education improved students' motivation and interest in the subject. This seems to have generated an increase in the number of the students who wish to continue chemistry education at higher levels. However, despite the fact that the majority of the studies have reported advantages of context-based chemistry studies, some of them have also referred to pitfalls, i.e. dominant

  13. Nitrogen Compounds in Radiation Chemistry

    International Nuclear Information System (INIS)

    Sims, H.E.; Dey, G.R.; Vaudey, C.E.; Peaucelle, C.; Boucher, J.L.; Toulhoat, N.; Bererd, N.; Koppenol, W.H.; Janata, E.; Dauvois, V.; Durand, D.; Legand, S.; Roujou, J.L.; Doizi, D.; Dannoux, A.; Lamouroux, C.

    2009-01-01

    Water radiolysis in presence of N 2 is probably the topic the most controversy in the field of water radiolysis. It still exists a strong discrepancy between the different reports of ammonia formation by water radiolysis in presence of N 2 and moreover in absence of oxygen there is no agreement on the formation or not of nitrogen oxide like NO 2 - and NO 3 -. These discrepancies come from multiple sources: - the complexity of the reaction mechanisms where nitrogen is involved - the experimental difficulties - and, the irradiation conditions. The aim of the workshop is to capitalize the knowledge needed to go further in simulations and understanding the problems caused (or not) by the presence of nitrogen / water in the environment of radioactive materials. Implications are evident in terms of corrosion, understanding of biological systems and atmospheric chemistry under radiation. Topics covered include experimental and theoretical approaches, application and fundamental researches: - Nitrate and Ammonia in radiation chemistry in nuclear cycle; - NOx in biological systems and atmospheric chemistry; - Formation of Nitrogen compounds in Nuclear installations; - Nitrogen in future power plant projects (Gen4, ITER...) and large particle accelerators. This document gathers the transparencies available for 7 of the presentations given at this workshop. These are: - H.E SIMS: 'Radiation Chemistry of Nitrogen Compounds in Nuclear Power Plant'; - G.R. DEY: 'Nitrogen Compounds Formation in the Radiolysis of Aqueous Solutions'; - C.E. VAUDEY et al.: 'Radiolytic corrosion of nuclear graphite studied with the dedicated gas irradiation cell of IPNL'; - J.L. BOUCHER: 'Roles and biosynthesis of NO in eukaryotes and prokaryotes'; - W.H. KOPPENOL: 'Chemistry of NOx'; - E. JANATA: 'Yield of OH in N 2 O saturated aqueous solution'; - V. DAUVOIS: 'Analytical strategy for the study of radiolysis gases'

  14. Technetium chemistry

    International Nuclear Information System (INIS)

    Burns, C.; Bryan, J.; Cotton, F.; Ott, K.; Kubas, G.; Haefner, S.; Barrera, J.; Hall, K.; Burrell, A.

    1996-01-01

    Technetium chemistry is a young and developing field. Despite the limited knowledge of its chemistry, technetium is the workhorse for nuclear medicine. Technetium is also a significant environmental concern because it is formed as a byproduct of nuclear weapons production and fission-power generators. Development of new technetium radio-pharmaceuticals and effective environmental control depends strongly upon knowledge of basic technetium chemistry. The authors performed research into the basic coordination and organometallic chemistry of technetium and used this knowledge to address nuclear medicine and environmental applications. This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL)

  15. Influence of water chemistry on fuel cladding behaviour. Proceedings of a technical committee meeting

    International Nuclear Information System (INIS)

    1997-02-01

    For the purpose of the meeting water chemistry included the actual practice, the water chemistry monitoring and the on-going research. Corrosion included also hydriding, recent observations made in reactors, modelling and the recent research carried out. Fifty seven participants representing twenty countries attended the thirty formal presentations and the subsequent discussions. The thirty papers presented were split into five sessions covering, Reactor experience, Mechanism and Modelling, Oxidation and hydriding, On-line monitoring of water chemistry and the review of existing and advanced water chemistries. Four panel discussions including ''Corrosion mechanism and Modelling'', ''Corrosion and Hydriding'', ''Plant Experience and Loop Experiments'', Water Chemistry, Current Practice and Emerging Solutions'' and ''On-line Monitoring of Water Chemistry and Corrosion'' were organized. The main points of discussion focussed on the optimization of water chemistry, the compatibility of potassium water chemistry with the utilization of Zircaloy 4 or the utilization of zirconium niobium cladding with lithium water chemistry. The effect of the fabrication route and of the cladding composition (Sn content) on the corrosion kinetics, the state of the art and the correlative gaps in cladding corrosion modelling and the recent developments of on-line monitoring of water chemistry together with examination of suitable developments, were also discussed. Refs, figs, tabs

  16. Influence of water chemistry on fuel cladding behaviour. Proceedings of a technical committee meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-02-01

    For the purpose of the meeting water chemistry included the actual practice, the water chemistry monitoring and the on-going research. Corrosion included also hydriding, recent observations made in reactors, modelling and the recent research carried out. Fifty seven participants representing twenty countries attended the thirty formal presentations and the subsequent discussions. The thirty papers presented were split into five sessions covering, Reactor experience, Mechanism and Modelling, Oxidation and hydriding, On-line monitoring of water chemistry and the review of existing and advanced water chemistries. Four panel discussions including ``Corrosion mechanism and Modelling``, ``Corrosion and Hydriding``, ``Plant Experience and Loop Experiments``, Water Chemistry, Current Practice and Emerging Solutions`` and ``On-line Monitoring of Water Chemistry and Corrosion`` were organized. The main points of discussion focussed on the optimization of water chemistry, the compatibility of potassium water chemistry with the utilization of Zircaloy 4 or the utilization of zirconium niobium cladding with lithium water chemistry. The effect of the fabrication route and of the cladding composition (Sn content) on the corrosion kinetics, the state of the art and the correlative gaps in cladding corrosion modelling and the recent developments of on-line monitoring of water chemistry together with examination of suitable developments, were also discussed. Refs, figs, tabs.

  17. Basic radiation chemistry for the ionising energy treatment of food

    International Nuclear Information System (INIS)

    Moore, P.W.

    1985-01-01

    Before we can understand the chemistry involved in the irradiation of complex substances such as food we need to have some appreciation of the reactions involved and the products formed when ionising energy interacts with the simple substances such as water and dilute solutions. Reactions involving hydrated electrons, hydrogen atoms and hydroxyl radicals are examined and methods for minimising radiolytic effects in foods are discussed

  18. Effects of Chemistry on Blunt-Body Wake Structure

    Science.gov (United States)

    Dogra, Virendra K.; Moss, James N.; Wilmoth, Richard G.; Taylor, Jeff C.; Hassan, H. A.

    1995-01-01

    Results of a numerical study are presented for hypersonic low-density flow about a 70-deg blunt cone using direct simulation Monte Carlo (DSMC) and Navier-Stokes calculations. Particular emphasis is given to the effects of chemistry on the near-wake structure and on the surface quantities and the comparison of the DSMC results with the Navier-Stokes calculations. The flow conditions simulated are those experienced by a space vehicle at an altitude of 85 km and a velocity of 7 km/s during Earth entry. A steady vortex forms in the near wake for these freestream conditions for both chemically reactive and nonreactive air gas models. The size (axial length) of the vortex for the reactive air calculations is 25% larger than that of the nonreactive air calculations. The forebody surface quantities are less sensitive to the chemistry than the base surface quantities. The presence of the afterbody has no effect on the forebody flow structure or the surface quantities. The comparisons of DSMC and Navier-Stokes calculations show good agreement for the wake structure and the forebody surface quantities.

  19. Density functional theory-based prediction of the formation constants of complexes of ammonia in aqueous solution: indications of the role of relativistic effects in the solution chemistry of gold(I).

    Science.gov (United States)

    Hancock, Robert D; Bartolotti, Libero J

    2005-10-03

    A prediction of the formation constants (log K1) for complexes of metal ions with a single NH3 ligand in aqueous solution, using quantum mechanical calculations, is reported. DeltaG values at 298 K in the gas phase for eq 1 (DeltaG(DFT)) were calculated for 34 metal ions using density functional theory (DFT), with the expectation that these would correlate with the free energy of complex formation in aqueous solution (DeltaG(aq)). [M(H2O)6]n+(g) + NH(3)(g) = [M(H2O)5NH3]n+(g) + H2O(g) (eq 1). The DeltaG(aq) values include the effects of complex changes in solvation on complex formation, which are not included in eq 1. It was anticipated that such changes in solvation would be constant or vary systematically with changes in the log K(1) value for different metal ions; therefore, simple correlations between DeltaG(DFT) and DeltaG(aq) were sought. The bulk of the log K1(NH3) values used to calculate DeltaG(aq) were not experimental, but estimated previously (Hancock 1978, 1980) from a variety of empirical correlations. Separate linear correlations between DeltaG(DFT) and DeltaG(aq) for metal ions of different charges (M2+, M3+, and M4+) were found. In plots of DeltaG(DFT) versus DeltaG(aq), the slopes ranged from 2.201 for M2+ ions down to 1.076 for M4+ ions, with intercepts increasing from M2+ to M4+ ions. Two separate correlations occurred for the M3+ ions, which appeared to correspond to small metal ions with a coordination number (CN) of 6 and to large metal ions with a higher CN in the vicinity of 7-9. The good correlation coefficients (R) in the range of 0.97-0.99 for all these separate correlations suggest that the approach used here may be the basis for future predictions of aqueous phase chemistry that would otherwise be experimentally inaccessible. Thus, the log K1(NH3) value for the transuranic Lr3+, which has a half-life of 3.6 h in its most stable isotope, is predicted to be 1.46. These calculations should also lead to a greater insight into the factors

  20. Fundamentals of nuclear chemistry

    International Nuclear Information System (INIS)

    Majer, V.

    1982-01-01

    The author of the book has had 25 years of experience at the Nuclear Chemistry of Prague Technical University. In consequence, the book is intended as a basic textbook for students of this field. Its main objectives are an easily understandable presentation of the complex subject and in spite of the uncertainty which still characterizes the definition and subjects of nuclear chemistry - a systematic classification and logical structure. Contents: 1. Introduction (history and definition); 2. General nuclear chemistry (physical fundamentals, hot atom chemistry, interaction of nuclear radiation with matter, radioactive elements, isotope effects, isotope exchange, chemistry of radioactive trace elements); 3. Methods of nuclear chemistry of nuclear chemistry (radiochemical methods, activation, separation and enrichment chemistry); 4. Preparative nuclear chemistry (isotope production, labelled compounds); 5. Analytival nuclear chemistry; 6. Applied nuclear chemistry (isotope applications in general physical and analytical chemistry). The book is supplemented by an annex with tables, a name catalogue and a subject index which will facilitate access to important information. (RB) [de

  1. Ions in solution basic principles of chemical interactions

    CERN Document Server

    Burgess, J

    1999-01-01

    This outline of the principles and chemical interactions in inorganic solution chemistry delivers a course module in an area of considerable complexity. Problems with solutions and tutorial hints to test comprehension have been added as a feature to check readers' understanding and assist self-study. Exercises and projects are also provided to help readers deepen and extend their knowledge and understanding. Inorganic solution chemistry is treated thoroughly Emphasis is placed upon NMR, UV-VIS, IR Raman spectroscopy, X-ray diffraction, and such topics as acid-base behaviour, stability constants and kinetics.

  2. Nuclear chemistry

    International Nuclear Information System (INIS)

    Vertes, A.; Kiss, I.

    1987-01-01

    This book is an introduction to the application of nuclear science in modern chemistry. The first group of chapters discuss the basic phenomena and concepts of nuclear physics with emphasis on their relation to chemical problems, including the main properties and the composition of atomic nuclei, nuclear reactions, radioactive decay and interactions of radiation with matter. These chapters provide the basis for understanding the following chapters which encompass the wide scope of nuclear chemistry. The methods of the investigation of chemical structure based on the interaction of nuclear radiation with matter including positronium chemistry and other exotic atoms is elaborated in particular detail. Separate chapters are devoted to the use of radioactive tracers, the chemical consequences of nuclear processes (i.e. hot atom chemistry), radiation chemistry, isotope effects and their applications, and the operation of nuclear reactors

  3. Nuclear chemistry

    International Nuclear Information System (INIS)

    Vertes, A.; Kiss, I.

    1987-01-01

    This book is an introduction to the application of nuclear science in modern chemistry. The first group of chapters discuss the basic phenomena and concepts of nuclear physics with emphasis on their relation to chemical problems, including the main properties and the composition of atomic nuclei, nuclear reactions, radioactive decay and interactions of radiation with matter. These chapters provide the basis for understanding the following chapters which encompass the wide scope of nuclear chemistry. The methods of the investigation of chemical structure based on the interaction of nuclear radiation with matter including positronium chemistry and other exotic atoms is elaborated in particular detail. Separate chapters are devoted to the use of radioactive tracers, the chemical consequences of nuclear processes (i.e. hot atom chemistry), radiation chemistry, isotope effects and their applications, and the operation of nuclear reactors. (Auth.)

  4. A context based approach using Green Chemistry/Bio-remediation principles to enhance interest and learning of organic chemistry in a high school AP chemistry classroom

    Science.gov (United States)

    Miller, Tricia

    The ability of our planet to sustain life and heal itself is not as predictable as it used to be. Our need for educated future scientists who know what our planet needs, and can passionately apply that knowledge to find solutions should be at the heart of science education today. This study of learning organic chemistry through the lens of the environmental problem "What should be done with our food scraps?" explores student interest, and mastery of certain concepts in organic chemistry. This Green Chemistry/ Bio-remediation context-based teaching approach utilizes the Nature MillRTM, which is an indoor food waste composting machine, to learn about organic chemistry, and how this relates to landfill reduction possibilities, and resource production. During this unit students collected food waste from their cafeteria, and used the Nature MillRTM to convert food waste into compost. The use of these hands on activities, and group discussions in a context-based environment enhanced their interest in organic chemistry, and paper chromatography. According to a one-tailed paired T-test, the result show that this context-based approach is a significant way to increase both student interest and mastery of the content.

  5. Coupling between water chemistry and thermal output at unsaturated repositories

    International Nuclear Information System (INIS)

    Walton, J.; LeMone, D.; Casey, D.

    1995-01-01

    This paper summarizes issues in predicting thermohydrology in the near field of a deep geological repository and the implications for performance assessment. Predicted thermohydrology depends on waste package design, and particularly on backfill materials. The coupling between solute concentrations and thermal gradients leads to a prediction of highly variable water chemistry in the near field which is radically different than the initial, undisturbed water chemistry; however, most analyses to date assume that waste package chemistry is approximately the same as initial pore water chemistry. Several alternative, simplified approaches for performance assessment are discussed

  6. Chemistry Division. Quarterly progress report for period ending June 30, 1949

    Energy Technology Data Exchange (ETDEWEB)

    1949-09-14

    Progress reports are presented for the following tasks: (1) nuclear and chemical properties of heavy elements (solution chemistry, phase rule studies); (2) nuclear and chemical properties of elements in the fission product region; (3) general nuclear chemistry; (4) radio-organic chemistry; (5) chemistry of separations processes; (6) physical chemistry and chemical physics; (7) radiation chemistry; (8) physical measurements and instrumentation; and (9) analytical chemistry. The program of the chemistry division is divided into two efforts of approximately equal weight with respect to number of personnel, chemical research, and analytical service for the Laboratory. The various research problems fall into the following classifications: (1) chemical separation processes for isolation and recovery of fissionable material, production of radioisotopes, and military applications; (2) reactor development; and (3) fundamental research.

  7. Forefront of PUREX system engineering. Chemistry and engineering of ruthenium, technetium and neptunium

    International Nuclear Information System (INIS)

    2004-07-01

    The paper reports the activity of the research committee organized by the Atomic Energy Society of Japan on 'Ruthenium and Technetium Chemistry in the PUREX System', with focusing on basic behaviors of ruthenium, technetium and neptunium in the PUREX process, the principles of plant design, and behaviors during the final waste treatment. The scope of the work includes the following major topics: (1) basic solution and solid-state chemistry; (2) basic solution and solid-state chemistry of minor actinides in particular, Np; (3) partitioning chemistry in the PUREX system and environmental behavior of the components; (4) processes of recovery, purification, and utilization of rare metal fission products; (5) field data on plant design, operation, decontamination, and decommissioning; (6) numerical process simulations and process control technologies; (7) compilation of a data base for process chemistry and plant engineering. (S. Ohno)

  8. Spectroscopy and chemistry of uranium IV

    International Nuclear Information System (INIS)

    Folcher, G.; Rigny, P.

    1980-06-01

    Different fundamental research papers on uranium IV are presented, some were never edited. Molecular spectroscopy was used for identification and structural study of uranium IV in aqueous or organic solutions. The fields studied are: coordination, stereochemistry, electronic structure and chemical properties. For interpretation of results some studies were made with solid compounds or with thorium compounds or thorium complexes. Knowledge of actinides chemistry is improved, uranium and thorium being models for 5 f ions, extractive chemistry is better understood and new applications are possible [fr

  9. Through the looking glass of a chemistry video game: Evaluating the effects of different MLEs presenting identical content material

    Science.gov (United States)

    Hillman, Dustin S.

    The primary goal of this study is to evaluate the effects of different media-based learning environments (MLEs) that present identical chemistry content material. This is done with four different MLEs that utilize some or all components of a chemistry-based media-based prototype video game. Examination of general chemistry student volunteers purposefully randomized to one of four different MLEs did not provide evidence that the higher the level of interactivity resulted in a more effective MLE for the chemistry content. Data suggested that the cognitive load to play the chemistry-based video game may impaired the chemistry content being presented and recalled by the students while the students watching the movie of the chemistry-based video game were able to recall the chemistry content more efficiently. Further studies in this area need to address the overall cognitive load of the different MLEs to potentially better determine what the most effective MLE may be for this chemistry content.

  10. Effects of '"Environmental Chemistry" Elective Course via Technology-Embedded Scientific Inquiry Model on Some Variables

    Science.gov (United States)

    Çalik, Muammer; Özsevgeç, Tuncay; Ebenezer, Jazlin; Artun, Hüseyin; Küçük, Zeynel

    2014-01-01

    The purpose of this study is to examine the effects of "environmental chemistry" elective course via Technology-Embedded Scientific Inquiry (TESI) model on senior science student teachers' (SSSTs) conceptions of environmental chemistry concepts/issues, attitudes toward chemistry, and technological pedagogical content knowledge…

  11. Effectiveness of Case-Based Learning Instruction on Epistemological Beliefs and Attitudes toward Chemistry

    Science.gov (United States)

    Cam, Aylin; Geban, Omer

    2011-01-01

    The purpose of the study was to investigate the effectiveness of case-based learning instruction over traditionally designed chemistry instruction on eleventh grade students' epistemological beliefs and their attitudes toward chemistry as a school subject. The subjects of this study consisted of 63 eleventh grade students from two intact classes…

  12. Soil chemistry in lithologically diverse datasets: the quartz dilution effect

    Science.gov (United States)

    Bern, Carleton R.

    2009-01-01

    National- and continental-scale soil geochemical datasets are likely to move our understanding of broad soil geochemistry patterns forward significantly. Patterns of chemistry and mineralogy delineated from these datasets are strongly influenced by the composition of the soil parent material, which itself is largely a function of lithology and particle size sorting. Such controls present a challenge by obscuring subtler patterns arising from subsequent pedogenic processes. Here the effect of quartz concentration is examined in moist-climate soils from a pilot dataset of the North American Soil Geochemical Landscapes Project. Due to variable and high quartz contents (6.2–81.7 wt.%), and its residual and inert nature in soil, quartz is demonstrated to influence broad patterns in soil chemistry. A dilution effect is observed whereby concentrations of various elements are significantly and strongly negatively correlated with quartz. Quartz content drives artificial positive correlations between concentrations of some elements and obscures negative correlations between others. Unadjusted soil data show the highly mobile base cations Ca, Mg, and Na to be often strongly positively correlated with intermediately mobile Al or Fe, and generally uncorrelated with the relatively immobile high-field-strength elements (HFS) Ti and Nb. Both patterns are contrary to broad expectations for soils being weathered and leached. After transforming bulk soil chemistry to a quartz-free basis, the base cations are generally uncorrelated with Al and Fe, and negative correlations generally emerge with the HFS elements. Quartz-free element data may be a useful tool for elucidating patterns of weathering or parent-material chemistry in large soil datasets.

  13. Variability in chemistry of surface and soil waters of an ...

    African Journals Online (AJOL)

    Water chemistry is important for the maintenance of wetland structure and function. Interpreting ecological patterns in a wetland system therefore requires an in-depth understanding of the water chemistry of that system. We investigated the spatial distribution of chemical solutes both in soil pore water and surface water, ...

  14. Use of pulse radiolysis for the study of the chemistry of aqueous ozone and ozonide solutions

    DEFF Research Database (Denmark)

    Sehested, Knud; Holcman, Jerzy; Bjergbakke, Erling

    1986-01-01

    The chemistry of aqeous ozone, O3, and ozonide, O3−, is of great interest from a technological, environmental and scientific point of view. The literature about their aqueous chemistry is extensive, the reaction mechanisms are still not well understood. The ozonide anion is a free radical that is...... reactions and provides kinetic data sufficient for computer simulations of aqueous O3/O3− chemistry.......The chemistry of aqeous ozone, O3, and ozonide, O3−, is of great interest from a technological, environmental and scientific point of view. The literature about their aqueous chemistry is extensive, the reaction mechanisms are still not well understood. The ozonide anion is a free radical...

  15. Liquid phase hot atom chemistry: At crossroads

    International Nuclear Information System (INIS)

    Rack, E.P.; Veterans Administration Medical Center, Omaha, NE

    1981-01-01

    The state of current research in liquid phase hot atom chemistry is discussed. Four classes of experimental approaches are high-lighted. These include 1) primary physical data for (n,γ)-activated 128 I, (I.T.)-activated 130 I and effects on chemical reactivity; 2) the density-variation technique involving iodine reactions with saturated and unsaturated hydrocarbons; 3) stereochemistry experiments on chlorocarbon molecules with single and multiple chiral centers; and 4) experiments employing dilute aqueous solutions of halogenerated biomolecules in the ice state, exposed to neutron irradiation. (orig.) [de

  16. Simulating the long-term chemistry of an upland UK catchment: Major solutes and acidification

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, E. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)]. E-mail: et@ceh.ac.uk; Lawlor, A.J. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Lofts, S. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)

    2006-05-15

    CHUM-AM was used to investigate changes in soil and water chemical variables in four moorland sub-catchments in Cumbria UK, to which non-marine S deposition has declined by 65% since the 1970s. The principal processes represented in the model comprise N and S uptake and release, water movements, the binding of cations by soil organic matter, chemical interactions in solution, and chemical weathering. CHUM-AM reproduced reasonably well the current soil pH and pools of N and S, and changes in streamwater chemistry over the period 1970-2000, notably decreases in the concentrations of alkaline earth cations and sulphate, and increases in pH. The model also predicts streamwater pH-Al relationships in agreement with observations. Predictive calculations suggest that constant atmospheric deposition of N at present rates will lead to N saturation and re-acidification, whereas a 50% reduction in N would stabilise soil and streamwater pH at about the present levels. - CHUM-AM accounts for recovery from acidification due to sulphur deposition, but predicts re-acidification if nitrogen deposition is not reduced.

  17. Solution Calorimetry Experiments for Physical Chemistry.

    Science.gov (United States)

    Raizen, Deborah A.; And Others

    1988-01-01

    Presents two experiments: the first one measures the heat of an exothermic reaction by the reduction of permanganate by the ferris ion; the second one measures the heat of an endothermic process, the mixing of ethanol and cyclohexane. Lists tables to aid in the use of the solution calorimeter. (MVL)

  18. Effects of solution pH and complexing reagents on uranium and thorium desorption under saturated equilibrium conditions

    International Nuclear Information System (INIS)

    Wang, Yug-Yea; Yu, C.

    1992-01-01

    Three contaminated bulk surface soils were used for investigating the effect of solution pH and complexing reagents on uranium and thorium desorption. At a low solution pH, the major chemical species of uranium and thorium, uranyl UO 2 +2 , thorium dihydroxide Th(OH) 2 +2 , and thorium hydroxide Th(OH) +3 , tend to form complexes with acetates in the solution phase, which increases the fractions of uranium and thorium desorbed into this phase. At a high solution pH, important uranium and thorium species such as uranyl tricarbonate complex UO 2 (CO) 33 -4 and thorium tetrahydroxide complex Th(OH) 4 tend to resist complexation with acetates. The presence of complexing reagents in solution can release radionuclides such as uranium and/or thorium from the soil to the solution by forming soluble complexes. Sodium bicarbonate (NaHCO 3 ) and diethylenetriaminepentaacetic acid (DTPA) are strong complex formers that released 38% to 62% of total uranium activity and 78% to 86% of total thorium activity, respectively, from the soil samples investigated. Solutions of 0.1 molar sodium nitrate (NaNO 3 ) and 0.1 molar sodium sulfate (Na 2 SO 4 ) were not effective complex formers with uranium and thorium under the experimental conditions. Fractions of uranium and thorium desorbed by 0.15g/200ml humic acid ranged from 4.62% to 6.17% and 1.59% to 7.09%, respectively. This work demonstrates the importance of a knowledge of solution chemistry in investigating the desorption of radionuclides

  19. Progress report 1981-1982. Reactor Chemistry Department

    International Nuclear Information System (INIS)

    1983-08-01

    Review of the activities performed by the Reactor Chemistry Department of the National Atomic Energy Commission of Argentina during 1981-1982. This Department provides services and assistance in all matters related to water chemistry and nuclear reactors chemistry, in all their phases: design, construction, commissioning and decommissioning. During this period, the following tasks were performed: study of the metallic oxide-water interphases; determination of the goethite and magnetite surficial charges; synthesis of the monodispersed nickel ferrites; study of the iron oxides dissolution mechanism in presence of different complexing agents; chemical decontamination of structural metals; thermodynamics of the water-nitrogen system; physico-chemical studies of aqueous solutions at high temperatures; hydrothermal decomposition of ionic exchange resines and study of the equilibria of the anionic exchange for the chemistry of pressurized reactor's primary loops. The appendix includes information on the Reactor Chemistry Department staff, its publications, services, seminars, courses and conferences performed during 1981-1982. (R.J.S.) [es

  20. EFFECTS OF 5E LEARNING CYCLE ON STUDENTS ACHIEVEMENT IN BIOLOGY AND CHEMISTRY

    Directory of Open Access Journals (Sweden)

    Patrick Osawaru Ajaja,

    2012-01-01

    Full Text Available The major purpose of this study was to determine the effects of learning cycle as an instructional strategy on biology andchemistry students achievement. To guide this study, six research hypotheses were stated and tested at 0.05 level ofsignificance. The design of this study was 2x2x3x6 Pre-test Post-test non-equivalent control group quasi experimental design.These included two instructional groups (experimental and control groups, sex (male and female, repeated testing (Pre,Post and follow-up tests, and six weeks of experience. The samples of the study included six senior secondary schools, 112science students, and 12 biology and chemistry teachers. The instruments used for this study were: teacher’s questionnaireon knowledge and use of learning cycle (KULC; and Biology and Chemistry Achievement Test (BCAT. The data collected wereanalyzed with simple percentage, Analysis of Covariance (ANCOVA and student t-test statistics. The major findings of thestudy included that only 30.43% and 26.31% of biology and chemistry teachers have the knowledge that learning cycle is aninstructional method; all the biology and chemistry teachers sampled have never used learning cycle as an instructionalmethod; learning cycle had a significant effect on students achievement in biology and chemistry; students taught withlearning cycle significantly achieved better in biology/chemistry Post-test than those taught with lecture method; the posttestscores of students in the learning cycle group increased over the period of experience; non-significant difference in Posttestscores between males and females taught with learning cycle; non-significant interaction effect between method andsex on achievement; and a significant higher retention of biology and chemistry knowledge by students taught with learningcycle than those taught with lecture method. It was concluded that the method seems an appropriate instructional modelthat could be used to solve the problems of

  1. Impact of water chemistry on surface charge and aggregation of polystyrene microspheres suspensions.

    Science.gov (United States)

    Lu, Songhua; Zhu, Kairuo; Song, Wencheng; Song, Gang; Chen, Diyun; Hayat, Tasawar; Alharbi, Njud S; Chen, Changlun; Sun, Yubing

    2018-07-15

    The discharge of microplastics into aquatic environment poses the potential threat to the hydrocoles and human health. The fate and transport of microplastics in aqueous solutions are significantly influenced by water chemistry. In this study, the effect of water chemistry (i.e., pH, foreign salts and humic acid) on the surface charge and aggregation of polystyrene microsphere in aqueous solutions was conducted by batch, zeta potentials, hydrodynamic diameters, FT-IR and XPS analysis. Compared to Na + and K + , the lower negative zeta potentials and larger hydrodynamic diameters of polystyrene microspheres after introduction of Mg 2+ were observed within a wide range of pH (2.0-11.0) and ionic strength (IS, 0.01-500mmol/L). No effect of Cl - , HCO 3 - and SO 4 2- on the zeta potentials and hydrodynamic diameters of polystyrene microspheres was observed at low IS concentrations (10mmol/L). The zeta potentials of polystyrene microspheres after HA addition were decreased at pH2.0-11.0, whereas the lower hydrodynamic diameters were observed at pH<4.0. According to FT-IR and XPS analysis, the change in surface properties of polystyrene microspheres after addition of hydrated Mg 2+ and HA was attributed to surface electrostatic and/or steric repulsions. These investigations are crucial for understanding the effect of water chemistry on colloidal stability of microplastics in aquatic environment. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Examining the Effects of Reflective Journals on Pre-Service Science Teachers' General Chemistry Laboratory Achievement

    Science.gov (United States)

    Cengiz, Canan; Karatas, Faik Özgür

    2015-01-01

    The general chemistry laboratory is an appropriate place for learning chemistry well. It is also effective for stimulating higher-order thinking skills, including reflective thinking, a skill that is crucial for science teaching as well as learning. This study aims to examine the effects of feedback-supported reflective journal-keeping activities…

  3. Visualizing Chemistry: Investigations for Teachers.

    Science.gov (United States)

    Ealy, Julie B.; Ealy, James L., Jr.

    This book contains 101 investigations for chemistry classrooms. Topics include: (1) Physical Properties; (2) Reactions of Some Elements; (3) Reactions Involving Gases; (4) Energy Changes; (5) Solutions and Solubility; (6) Transition Metals and Complex Ions; (7) Kinetics and Equilibrium; (8) Acids and Bases; (9) Oxidation-Reduction; (10)…

  4. A new method to measure effective soil solution concentration predicts copper availability to plants.

    Science.gov (United States)

    Zhang, H; Zhao, F J; Sun, B; Davison, W; McGrath, S P

    2001-06-15

    Risk assessments of metal contaminated soils need to address metal bioavailability. To predict the bioavailability of metals to plants, it is necessary to understand both solution and solid phase supply processes in soils. In striving to find surrogate chemical measurements, scientists have focused either on soil solution chemistry, including free ion activities, or operationally defined fractions of metals. Here we introduce the new concept of effective concentration, CE, which includes both the soil solution concentration and an additional term, expressed as a concentration, that represents metal supplied from the solid phase. CE was measured using the technique of diffusive gradients in thin films (DGT) which, like a plant, locally lowers soil solution concentrations, inducing metal supply from the solid phase, as shown by a dynamic model of the DGT-soil system. Measurements of Cu as CE, soil solution concentration, by EDTA extraction and as free Cu2+ activity in soil solution were made on 29 different soils covering a large range of copper concentrations. Theywere compared to Cu concentrations in the plant material of Lepidium heterophyllum grown on the same soils. Plant concentrations were linearly related and highly correlated with CE but were more scattered and nonlinear with respect to free Cu2+ activity, EDTA extraction, or soil solution concentrations. These results demonstrate that the dominant supply processes in these soils are diffusion and labile metal release, which the DGT-soil system mimics. The quantity CE is shown to have promise as a quantitative measure of the bioavailable metal in soils.

  5. Effects of `Environmental Chemistry' Elective Course Via Technology-Embedded Scientific Inquiry Model on Some Variables

    Science.gov (United States)

    Çalik, Muammer; Özsevgeç, Tuncay; Ebenezer, Jazlin; Artun, Hüseyin; Küçük, Zeynel

    2014-06-01

    The purpose of this study is to examine the effects of `environmental chemistry' elective course via Technology-Embedded Scientific Inquiry (TESI) model on senior science student teachers' (SSSTs) conceptions of environmental chemistry concepts/issues, attitudes toward chemistry, and technological pedagogical content knowledge (TPACK) levels. Within one group pre-test-post-test design, the study was conducted with 117 SSSTs (68 females and 49 males—aged 21-23 years) enrolled in an `environmental chemistry' elective course in the spring semester of 2011-2012 academic-years. Instruments for data collection comprised of Environmental Chemistry Conceptual Understanding Questionnaire, TPACK survey, and Chemistry Attitudes and Experiences Questionnaire. Significant increases in the SSSTs' conceptions of environmental chemistry concepts/issues, attitudes toward chemistry, and TPACK levels are attributed to the SSSTs learning how to use the innovative technologies in the contexts of the `environmental chemistry' elective course and teaching practicum. The study implies that the TESI model may serve a useful purpose in experimental science courses that use the innovative technologies. However, to generalize feasibility of the TESI model, it should be evaluated with SSSTs in diverse learning contexts.

  6. Evaluating the Effectiveness of the Chemistry Education by Using the Analytic Hierarchy Process

    Science.gov (United States)

    Yüksel, Mehmet

    2012-01-01

    In this study, an attempt was made to develop a method of measurement and evaluation aimed at overcoming the difficulties encountered in the determination of the effectiveness of chemistry education based on the goals of chemistry education. An Analytic Hierarchy Process (AHP), which is a multi-criteria decision technique, is used in the present…

  7. Effects of Computer Based Learning on Students' Attitudes and Achievements towards Analytical Chemistry

    Science.gov (United States)

    Akcay, Husamettin; Durmaz, Asli; Tuysuz, Cengiz; Feyzioglu, Burak

    2006-01-01

    The aim of this study was to compare the effects of computer-based learning and traditional method on students' attitudes and achievement towards analytical chemistry. Students from Chemistry Education Department at Dokuz Eylul University (D.E.U) were selected randomly and divided into three groups; two experimental (Eg-1 and Eg-2) and a control…

  8. NATO Advanced Research Workshop on The Chemistry of Weathering

    CERN Document Server

    1985-01-01

    Several important developments in our understanding of the chemistry of weathering have occurred in the last few years: 1. There has been a major breakthrough in our understanding of the mechanisms controlling the kinetics of sil icate dissolution, and there have been major advances in computer modeling of weathering processes. 2. There has been a growing recognition of the importance of organic solutes in the weathering process, and hence of the inter-relationships between mineral weathering and the terrestrial ecosystem. 3. The impact of acid deposition ("acid rain") has been widely recognized. The processes by which acid deposition is neutral ized are closely related to the processes of normal chemical weathering; an understanding of the chemistry of weathering is thus essential for predicting the effects of acid deposition. 4. More high-qual ity data have become available on the chemical dynamics of smal I watersheds and large river systems, which represent the integrated effects of chemical weathering.

  9. Summary Report for April, May and June, 1951, Chemistry Division, Section C-1

    Energy Technology Data Exchange (ETDEWEB)

    Manning, W. M. [Argonne National Lab. (ANL), Argonne, IL (United States). Chemistry Division; Osborne, D. W. [Argonne National Lab. (ANL), Argonne, IL (United States). Chemistry Division

    1951-08-01

    This is a summary report for April, May and June, 1951, in the Chemistry Division, Section C-1 of Argonne National Laboratory. Topics include Nuclear Chemistry and Radiochemistry with specifics about the following: 1) U238 (n,2n) Cross Section WIthin a Uranium Slug, and 2) Possible Occurrence of Si32 in Nature. Basic Chemistry is also covered, going into the following subjects: 1) Heats of Solution of Salts in Organic Solvents, 2) Effect of Coordination on Absorption Spectra of Anions, 3) Entropy, Enthalpy, and Heat Capacity of Thorium Dioxide from 10 to 300°K, 4) The Thermodynamics of Neptunium Ions, 5) Migration of Ions in Ion-Exchange Resins During Electrolysis, and 5) Mutual Separation of Lanthanides and Actinides by Solvent Extraction Techniques.

  10. The aqueous chemistry of oxides

    CERN Document Server

    Bunker, Bruce C

    2016-01-01

    The Aqueous Chemistry of Oxides is a comprehensive reference volume and special topics textbook that explores all of the major chemical reactions that take place between oxides and aqueous solutions. The book highlights the enormous impact that oxide-water reactions have in advanced technologies, materials science, geochemistry, and environmental science.

  11. Effect of Water Chemistry Variations on Corrosion of Zr-Alloys for BWR Applications

    International Nuclear Information System (INIS)

    Kim, Young-Jin; Yang- Lin, Pi; Lutz, Dan; Kucuk, Aylin; Cheng, Bo

    2012-09-01

    Two reference water chemistry conditions (60 ppb Zn and 60 μg/cm 2 Pt/Rh with either 500 ppb O 2 and 500 ppb H 2 O 2 , or 150 ppb H 2 ) were chosen for testing at 300 deg. C in refreshed autoclaves. For each reference water chemistry, the potential effects due to three chemical impurities of interest to BWRs (33 ppm Na, 10 ppm Li, and 10 ppm EHC fluid) were evaluated. Zircaloy-2 and GNF-Ziron (a Zr-based alloy with higher Fe additions than Zircaloy-2) cladding tubes were tested and the effects of tubing process variation and pre-filming were investigated. Tested channel materials included Zircaloy-2, Zircaloy-4, GNF-Ziron and NSF (a Zr-based alloy with Sn, Nb and Fe additions). The corrosion weight gain and hydrogen absorption were measured up to 12 months of exposure for a given water chemistry condition. Tests under 150 ppb H 2 based water chemistry, with or without chemical impurities, generally resulted in greater amounts of corrosion after 12 month exposure compared with 500 ppb O 2 and 500 ppb H 2 O 2 based water chemistries. Of the added chemical impurities, only 33 ppm Na addition produced slightly increased corrosion. Under various test conditions, the presence of a thin pre-film resulted in some initial corrosion benefits, but the benefits were no longer evident after 12 months exposure; however, slight hydrogen benefits remained. For GNF-Ziron cladding, hydrogen absorption was generally lower compared with similarly processed Zircaloy-2 under 150 ppb H 2 based water chemistry, when corrosion was generally higher. Of the channel material tested, NSF developed the lowest level of hydrogen absorption, particularly under 150 ppb H 2 based water chemistries. (authors)

  12. Bactericidal effects of plasma-modified surface chemistry of silicon nanograss

    International Nuclear Information System (INIS)

    Ostrikov, Kola; Macgregor-Ramiasa, Melanie; Cavallaro, Alex; Ostrikov, Kostya; Vasilev, Krasimir

    2016-01-01

    The surface chemistry and topography of biomaterials regulate the adhesion and growth of microorganisms in ways that are still poorly understood. Silicon nanograss structures prepared via inductively coupled plasma etching were coated with plasma deposited nanometer-thin polymeric films to produce substrates with controlled topography and defined surface chemistry. The influence of surface properties on Staphylococcus aureus proliferation is demonstrated and explained in terms of nanograss substrate wetting behaviour. With the combination of the nanograss topography; hydrophilic plasma polymer coatings enhanced antimicrobial activity while hydrophobic coatings reduced it. This study advances the understanding of the effects of surface wettability on the bactericidal properties of reactive nano-engineered surfaces. (paper)

  13. Recollections of the maturation of radiation chemistry

    International Nuclear Information System (INIS)

    Dainton, F.S.

    1989-01-01

    In this paper the background to the study of the identification of primary species in irradiated aqueous solutions is presented. Theoretical aspects are discussed. The radiation chemistry of glossy and crystalline solids is briefly discussed. (UK)

  14. A Comprehensive General Chemistry Demonstration

    Science.gov (United States)

    Sweeder, Ryan D.; Jeffery, Kathleen A.

    2013-01-01

    This article describes the use of a comprehensive demonstration suitable for a high school or first-year undergraduate introductory chemistry class. The demonstration involves placing a burning candle in a container adjacent to a beaker containing a basic solution with indicator. After adding a lid, the candle will extinguish and the produced…

  15. Effect Of Exogenous Progesterone On Blood Chemistry Of Large ...

    African Journals Online (AJOL)

    Exogenous hormones are major economic factors in swine production. This study evaluate the effects of exogenous administration of progesterone on the blood chemistry of pigs.Experiment involved weekly injections of progesterone to 24 pigs (12 males and 12 females)from day old to 24 weeks and only corn oil to another ...

  16. Investigating the Effectiveness of Computer Simulations for Chemistry Learning

    Science.gov (United States)

    Plass, Jan L.; Milne, Catherine; Homer, Bruce D.; Schwartz, Ruth N.; Hayward, Elizabeth O.; Jordan, Trace; Verkuilen, Jay; Ng, Florrie; Wang, Yan; Barrientos, Juan

    2012-01-01

    Are well-designed computer simulations an effective tool to support student understanding of complex concepts in chemistry when integrated into high school science classrooms? We investigated scaling up the use of a sequence of simulations of kinetic molecular theory and associated topics of diffusion, gas laws, and phase change, which we designed…

  17. Chemistry

    International Nuclear Information System (INIS)

    Ferris, L.M.

    1975-01-01

    The chemical research and development efforts related to the design and ultimate operation of molten-salt breeder reactor systems are concentrated on fuel- and coolant-salt chemistry, including the development of analytical methods for use in these systems. The chemistry of tellurium in fuel salt is being studied to help elucidate the role of this element in the intergranular cracking of Hastelloy N. Studies were continued of the effect of oxygen-containing species on the equilibrium between dissolved UF 3 and dissolved UF 4 , and, in some cases, between the dissolved uranium fluorides and graphite, and the UC 2 . Several aspects of coolant-salt chemistry are under investigation. Hydroxy and oxy compounds that could be formed in molten NaBF 4 are being synthesized and characterized. Studies of the chemistry of chromium (III) compounds in fluoroborate melts were continued as part of a systematic investigation of the corrosion of structural alloys by coolant salt. An in-line voltammetric method for determining U 4+ /U 3+ ratios in fuel salt was tested in a forced-convection loop over a six-month period. (LK)

  18. Chemistry and biology by new multiple choice

    International Nuclear Information System (INIS)

    Seo, Hyeong Seok; Kim, Seong Hwan

    2003-02-01

    This book is divided into two parts, the first part is about chemistry, which deals with science of material, atom structure and periodic law, chemical combination and power between molecule, state of material and solution, chemical reaction and an organic compound. The second part give description of biology with molecule and cell, energy in cells and chemical synthesis, molecular biology and heredity, function on animal, function on plant and evolution and ecology. This book has explanation of chemistry and biology with new multiple choice.

  19. Hydrolysis and Radiation Chemistry of the DGAs

    Energy Technology Data Exchange (ETDEWEB)

    Mincher, Bruce Jay [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zarzana, Christopher Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This document was prepared to meet FCR&D level 3 milestone M3FT-16IN030104052, “continue the study of the short chain compounds,” and, “ study the radiolysis of the non-symmetrical DGA (D3DODGA)….,” under the Radiation Chemistry FCR&D work package. Toward these goals, the short chain DGA, tetraethyldiglycolamide (TEDGA) was investigated for its hydrolytic stability in HNO3 solution, with comparisons to the less oxidizing mineral acid HCl. Initial gamma-irradiations were also performed on DGA solutions, to inform a more detailed investigation of several short chain compounds anticipated for FY17. The hydrolytic and radiolysis behavior of TEDGA is of interest for two reasons. First, previous long chain DGA radiolysis was conducted in dodecane solution since the long chain compounds are soluble in that diluent, and new radiation chemistry is expected in the aqueous environment due to reactions with •OH radical. The second reason is that this water-soluble DGA has been proposed for use as a stripping or holdback agent in both European and American fuel cycle scenarios. Therefore, this work was performed in collaboration Forschungszentrum Jülich (FZJ), and the European SACSESS program. Additionally, results are presented here regarding the radiation of chemistry the non-symmetrical DGA didodecyldioctyldiglycolamide (D3DODGA), for comparison to previous work with symmetrical DGAs such as TODGA and TEHDGA. This was also conducted in collaboration with researchers in the SACSESS program.

  20. DOE fundamentals handbook: Chemistry

    International Nuclear Information System (INIS)

    1993-01-01

    This handbook was developed to assist nuclear facility operating contractors in providing operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of chemistry. This volume contains the following modules: reactor water chemistry (effects of radiation on water chemistry, chemistry parameters), principles of water treatment (purpose; treatment processes [ion exchange]; dissolved gases, suspended solids, and pH control; water purity), and hazards of chemicals and gases (corrosives [acids, alkalies], toxic compounds, compressed gases, flammable/combustible liquids)

  1. Brahmaputra river basin groundwater: Solute distribution, chemical evolution and arsenic occurrences in different geomorphic settings

    Directory of Open Access Journals (Sweden)

    Swati Verma

    2015-09-01

    New hydrological insights for the region: Most groundwater solutes of RCD and YA terrains were derived from both silicate weathering and carbonate dissolution, while silicate weathering process dominates the solute contribution in OA groundwater. Groundwater samples from all terrains are postoxic with mean pe values between Fe(III and As(V–As(III reductive transition. While, reductive dissolution of (Fe–MnOOH is the dominant mechanism of As mobilization in RCD and YA aquifers, As in OA and PD aquifers could be mobilized by combined effect of pH dependent sorption and competitive ion exchange. The present study focuses on the major ion chemistry as well as the chemistry of the redox sensitive solutes of the groundwater in different geomorphic settings and their links to arsenic mobilization in groundwater.

  2. Progress in organic and physical chemistry structures and mechanisms

    CERN Document Server

    Zaikov, Gennady E; Lobanov, Anton V

    2013-01-01

    Progress in Organic and Physical Chemistry: Structures and Mechanisms provides a collection of new research in the field of organic and physical properties, including new research on: The physical principles of the conductivity of electrical conducting polymer compounds The dependence on constants of electromagnetic interactions upon electron spacial-energy characteristics Effects of chitosan molecultural weight on rehological behavior of chitosan modified nanoclay at hight hydrated state Bio-structural energy criteria of functional states in normal and pathological conditions Potentiometric study on the international between devalent cations and sodium carboxylates in aqueous solutions Structural characteristic changes in erythrocyte membranes of mice bearing Alzheimer's-like disease caused by the olfactory bulbetomy This volume is intended to provide an overview of new studies and research for engineers, faculty, researchers, and upper-level students in the field of organic and physical chemistry.

  3. Introduction to chemistry and applications in nature of mass independent isotope effects special feature.

    Science.gov (United States)

    Thiemens, Mark H

    2013-10-29

    Stable isotope ratio variations are regulated by physical and chemical laws. These rules depend on a relation with mass differences between isotopes. New classes of isotope variation effects that deviate from mass dependent laws, termed mass independent isotope effects, were discovered in 1983 and have a wide range of applications in basic chemistry and nature. In this special edition, new applications of these effects to physical chemistry, solar system origin models, terrestrial atmospheric and biogenic evolution, polar paleo climatology, snowball earth geology, and present day atmospheric sciences are presented.

  4. Structure and reaction of electrolytic solution. Denkaishitsu yoeki no kozo to hanno

    Energy Technology Data Exchange (ETDEWEB)

    Otaki, H. (Okazaki National Research Inst., Aichi (Japan))

    1990-07-05

    An electrolytic solution has been recognized as an ion transporting system since the oldest time in the history of electrochemistry, and the chemistry related thereto forms the most basic field of electrochemistry. In this article, the progress of chemistry concerning electrolytic solutions since M. Faraday is briefly stated, and in view of very scanty structural knowledge available on other solutions in comparison with the structure of water on which extensive studies have been made, the respective structures of such non-aqueous solutions as the mixed solvent of N,N-dimethylformamide (DMF)-acetonitrile (AN) and the mixed solvent of dimethylsulfoxide (DMSO)-2,2,2-triphloroethanol (TFE) are studied. In addition, concerning the solvation when ions exist in such a non-aqueous solvent mixed system, the selective solvation of Cu {sup 2+} ions in the DMF-AN and Cu {sup 2+} as well as Cl {sup {minus}} ions in the DMSO-TFE is respectively explained, and the solvent effect, etc. of Cu {sup 2+} ions and Cl {sup {minus}} ions on the complex forming reaction are discussed. 17 refs., 8 figs., 2 tabs.

  5. Chemistry for the nuclear energy of the future

    International Nuclear Information System (INIS)

    Chmielewski, A.G.

    2011-01-01

    Chemistry - radiochemistry, radiation chemistry and nuclear chemical engineering play a very important role in the nuclear power development. Even at present, the offered technology is well developed, but still several improvements are needed and proposed. These developments concern all stages of the technology; front end, reactor operation (coolant chemistry and installation components decontamination, noble gas release control), back end of fuel cycle, etc. Chemistry for a partitioning and a transmutation is a new challenge for the chemists and chemical engineers. The IV th generation of nuclear reactors cannot be developed without chemical solutions for fuel fabrication, radiation-coolants interaction phenomena understanding and spent fuel/waste treatment technologies elaboration. Radiochemical analytical methods are fundamental for radioecological monitoring of radioisotopes of natural and anthropological origin. This paper addresses just a few subjects and is not a detailed overview of the field, however it illustrates a role of chemistry for a safe and economical nuclear power development. (author)

  6. Present status of water chemistry in nuclear power plants

    International Nuclear Information System (INIS)

    Berge, Ph.; Fiquet, J.M.

    1991-01-01

    As operational experience increases, solutions to mitigate corrosion problems of existing plants are found. They also, hopefully, can solve the corrosion problems for future reactors when materials and design can be modified. Improvement of chemistry solved numerous early problems in PWRs (denting, pitting) and limitated other phenomena such as erosion-corrosion of steels in the secondary circuit. Chemistry has not been successful for other problems such as primary-side cracking of PWRs and has been moderately efficient for stress corrosion cracking or IGA of tubes at the support plate. Based on the experience, several recommendations for an optimum chemistry can be formulated. (author)

  7. Abstracts Book of 3. All-Polish Conference on Radiochemistry and Nuclear Chemistry

    International Nuclear Information System (INIS)

    2001-01-01

    The development of radiochemistry and nuclear chemistry in Poland have been presented during the 3. All-Polish Conference on Radiochemistry and Nuclear Chemistry held in Kazimierz Dolny in May 2001. The broad range of problems connected with radiochemistry and nuclear chemistry application in environmental protection and quality control, nuclear medicine and radiation protection, radioactive waste processing and many other scientific and everyday problems solution have been extensively presented and discussed

  8. Effectiveness of Analogy Instructional Strategy on Undergraduate Student's Acquisition of Organic Chemistry Concepts in Mutah University, Jordan

    Science.gov (United States)

    Samara, Nawaf Ahmad Hasan

    2016-01-01

    This study aimed at investigating the effectiveness of analogy instructional strategy on undergraduate students' acquisition of organic chemistry concepts in Mutah University, Jordan. A quasi-experimental design was used in the study; Participants were 97 students who enrolled in organic chemistry course at the department of chemistry during the…

  9. Combined LAURA-UPS solution procedure for chemically-reacting flows. M.S. Thesis

    Science.gov (United States)

    Wood, William A.

    1994-01-01

    A new procedure seeks to combine the thin-layer Navier-Stokes solver LAURA with the parabolized Navier-Stokes solver UPS for the aerothermodynamic solution of chemically-reacting air flowfields. The interface protocol is presented and the method is applied to two slender, blunted shapes. Both axisymmetric and three dimensional solutions are included with surface pressure and heat transfer comparisons between the present method and previously published results. The case of Mach 25 flow over an axisymmetric six degree sphere-cone with a noncatalytic wall is considered to 100 nose radii. A stability bound on the marching step size was observed with this case and is attributed to chemistry effects resulting from the noncatalytic wall boundary condition. A second case with Mach 28 flow over a sphere-cone-cylinder-flare configuration is computed at both two and five degree angles of attack with a fully-catalytic wall. Surface pressures are seen to be within five percent with the present method compared to the baseline LAURA solution and heat transfers are within 10 percent. The effect of grid resolution is investigated and the nonequilibrium results are compared with a perfect gas solution, showing that while the surface pressure is relatively unchanged by the inclusion of reacting chemistry the nonequilibrium heating is 25 percent higher. The procedure demonstrates significant, order of magnitude reductions in solution time and required memory for the three dimensional case over an all thin-layer Navier-Stokes solution.

  10. Ion binding by humic and fulvic acids: A computational procedure based on functional site heterogeneity and the physical chemistry of polyelectrolyte solutions

    International Nuclear Information System (INIS)

    Marinsky, J.A.; Reddy, M.M.; Ephraim, J.; Mathuthu, A.

    1988-04-01

    Ion binding equilibria for humic and fulvic acids are examined from the point of view of functional site heterogeneity and the physical chemistry of polyelectrolyte solutions. A detailed explanation of the potentiometric properties of synthetic polyelectrolytes and ion-exchange gels is presented first to provide the basis for a parallel consideration of the potentiometric properties exhibited by humic and fulvic acids. The treatment is then extended to account for functional site heterogeneity. Sample results are presented for analysis of the ion-binding reactions of a standard soil fulvic acid (Armadale Horizons Bh) with this approach to test its capability for anticipation of metal ion removal from solution. The ultimate refined model is shown to be adaptable, after appropriate consideration of the heterogeneity and polyelectrolyte factors, to programming already available for the consideration of ion binding by inorganics in natural waters. (orig.)

  11. Mid-year report: IPC liaison and chemistry of thermal reconstitution

    International Nuclear Information System (INIS)

    Delegard, C.H.

    1995-05-01

    A program of investigation into the chemistry of alkaline Hanford Site tank waste is being conducted. The investigations have two main subtasks: liaison with the Institute of Physical Chemistry of the Russian Academy of Sciences and further laboratory testing of the chemistry of thermal reconstitution of Hanford Site tank waste. Progress to date includes: (1) a technical dialogue has been established with the Institute scientists; (2) editing of a technical literature review on the chemistry of the transuranic elements and technetium in alkaline media written by researchers at the Institute is complete; (3) four tasks from the Institute have been selected for support by the US Department of Energy; (4) technical information has been supplied to the Institute describing the composition of Hanford Site tank waste; (5) tests, using genuine waste from tank 104-S (a REDOX Process sludge), comparing the performance of thermal reconstitution with enhanced sludge washing show markedly improved dissolution of aluminum achieved by the thermal treatment; (6) a reduction/coprecipitation method was tested and shown to remove plutonium, solubilized by thermal treatment, rapidly and efficiently from solution; (7) technical chemistry support was provided to calciner kinetics tests at the University of Idaho; (8) tests to determine the speciation of plutonium and neptunium solubilized by thermal treatment show dissolved Pu(V) and Np(V) hydroxide complexes are produced, a Np(V) peroxide complex also was identified; (9) recently published data on Pu(IV) carbonate complexation in moderately alkaline (pH 12 to 13) solution led to reexamination of previous investigations of plutonium complexation in highly alkaline (3 to 5 molar NaOH) solutions

  12. PWR secondary water chemistry study

    International Nuclear Information System (INIS)

    Pearl, W.L.; Sawochka, S.G.

    1977-02-01

    Several types of corrosion damage are currently chronic problems in PWR recirculating steam generators. One probable cause of damage is a local high concentration of an aggressive chemical even though only trace levels are present in feedwater. A wide variety of trace chemicals can find their way into feedwater, depending on the sources of condenser cooling water and the specific feedwater treatment. In February 1975, Nuclear Water and Waste Technology Corporation (NWT), was contracted to characterize secondary system water chemistry at five operating PWRs. Plants were selected to allow effects of cooling water chemistry and operating history on steam generator corrosion to be evaluated. Calvert Cliffs 1, Prairie Island 1 and 2, Surry 2, and Turkey Point 4 were monitored during the program. Results to date in the following areas are summarized: (1) plant chemistry variations during normal operation, transients, and shutdowns; (2) effects of condenser leakage on steam generator chemistry; (3) corrosion product transport during all phases of operation; (4) analytical prediction of chemistry in local areas from bulk water chemistry measurements; and (5) correlation of corrosion damage to chemistry variation

  13. Сombination of Knowledge of Mathematics and Chemistry in the Study of the Theme “Water Dissociation. Power of Hydrogen” in the Inorganic Chemistry Course

    OpenAIRE

    Melnyk, D. O.

    2014-01-01

    The aim of this work was to show effective and convenient way of studying the theme “Water Dissociation. Power of Hydrogen” and facilitate the new material perception by students of pharmaceutical faculty using knowledge of mathematics and chemistry. The correct calculation of pH and ions concentration in solution is necessary for complete perception of the theoretical bases of many disciplines. Using such approach in the study of this theme increases the student's ability to solve the proble...

  14. Progress report 1985-1986 Reactor Chemistry Department

    International Nuclear Information System (INIS)

    1987-12-01

    The report of the activities performed by the Reactor Chemistry Department of the National Atomic Energy Commission, during the period 1985-1986, covers works of investigation, development and service related to the Argentine Nuclear Power Plants. The main subjects are the experimental and theoretical studies about physical chemistry and chemistry control at the moderators and heat transport system of the nuclear power plants. The more relevant topics are related to: 1: Behaviour of gases, electrolites and other additives for nuclear power plants, at high temperature and pressure; 2: Ionic exchangers of nuclear degree; 3: Electrochemistry studies connected with the constitutive materials' corrosion and with the nuclear power plants decontamination processes; 4: Behaviour of suspensions and colloids in nuclear power plants; 5: Use of new additives for chemistry control of the oxides which are in the circuits of nuclear power plants; 6: Research methods that allow to check reactor's control quality; 7: Study of the radiolytic behaviour of nuclear reactor's solutions. (M.E.L.) [es

  15. Water chemistry regimes for VVER-440 units: water chemistry influence on fuel cladding behaviour

    International Nuclear Information System (INIS)

    Zmitko, M.

    1999-01-01

    In this lecture next problems of water chemistry influence on fuel cladding behaviour for VVER-440 units are presented: primary coolant technologies; water chemistry specification and control; fuel integrity considerations; zirconium alloys cladding corrosion (corrosion versus burn-up; water chemistry effect; crud deposition; hydrogen absorption; axial offset anomaly); alternatives for the primary coolant regimes

  16. The Effectiveness of Process-Oriented Guided Inquiry Learning to Reduce Alternative Conceptions in Secondary Chemistry

    Science.gov (United States)

    Barthlow, Michelle J.; Watson, Scott B.

    2014-01-01

    A nonequivalent, control group design was used to investigate student achievement in secondary chemistry. This study investigated the effect of process-oriented guided inquiry learning (POGIL) in high school chemistry to reduce alternate conceptions related to the particulate nature of matter versus traditional lecture pedagogy. Data were…

  17. The Combined Effects of Classroom Teaching and Learning Strategy Use on Students' Chemistry Self-Efficacy

    Science.gov (United States)

    Cheung, Derek

    2015-02-01

    For students to be successful in school chemistry, a strong sense of self-efficacy is essential. Chemistry self-efficacy can be defined as students' beliefs about the extent to which they are capable of performing specific chemistry tasks. According to Bandura (Psychol. Rev. 84:191-215, 1977), students acquire information about their level of self-efficacy from four sources: performance accomplishments, vicarious experiences, verbal persuasion, and physiological states. No published studies have investigated how instructional strategies in chemistry lessons can provide students with positive experiences with these four sources of self-efficacy information and how the instructional strategies promote students' chemistry self-efficacy. In this study, questionnaire items were constructed to measure student perceptions about instructional strategies, termed efficacy-enhancing teaching, which can provide positive experiences with the four sources of self-efficacy information. Structural equation modeling was then applied to test a hypothesized mediation model, positing that efficacy-enhancing teaching positively affects students' chemistry self-efficacy through their use of deep learning strategies such as metacognitive control strategies. A total of 590 chemistry students at nine secondary schools in Hong Kong participated in the survey. The mediation model provided a good fit to the student data. Efficacy-enhancing teaching had a direct effect on students' chemistry self-efficacy. Efficacy-enhancing teaching also directly affected students' use of deep learning strategies, which in turn affected students' chemistry self-efficacy. The implications of these findings for developing secondary school students' chemistry self-efficacy are discussed.

  18. Porewater chemistry in compacted bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Muurinen, A.; Lehikoinen, J. [VTT Chemical Technology, Espoo (Finland)

    1999-03-01

    In this study, the porewater chemistry in compacted bentonite, considered as an engineered barrier in the repository of spent fuel, has been studied in interaction experiments. Many parameters, like the composition and density of bentonite, composition of the solution, bentonite-to-water ratio (B/W), surrounding conditions and experimental time have been varied in the experiments. At the end of the interaction the equilibrating solution, the porewaters squeezed out of the bentonite samples, and bentonites themselves were analyzed to give information for the interpretation and modelling of the interaction. Equilibrium modelling was performed with the HYDRAQL/CE computer code 33 refs.

  19. VVER operational experience - effect of preconditioning and primary water chemistry on radioactivity build-up

    International Nuclear Information System (INIS)

    Zmitko, M.; Kysela, J.; Dudjakova, K.; Martykan, M.; Janesik, J.; Hanus, V.; Marcinsky, P.

    2004-01-01

    The primary coolant technology approaches currently used in VVER units are reviewed and compared with those used in PWR units. Standard and modified water chemistries differing in boron-potassium control are discussed. Preparation of the VVER Primary Water Chemistry Guidelines in the Czech Republic is noted. Operational experience of some VVER units, operated in the Czech Republic and Slovakia, in the field of the primary water chemistry, and radioactivity transport and build-up are presented. In Mochovce and Temelin units, a surface preconditioning (passivation) procedure has been applied during hot functional tests. The main principles of the controlled primary water chemistry applied during the hot functional tests are reviewed and importance of the water chemistry, technological and other relevant parameters is stressed regarding to the quality of the passive layer formed on the primary system surfaces. The first operational experience obtained in the course of beginning of these units operation is presented mainly with respect to the corrosion products coolant and surface activities. Effect of the initial passivation performed during hot functional tests and the primary water chemistry on corrosion products radioactivity level and radiation situation is discussed. (author)

  20. Gas phase chemistry studies of transactinoid elements and the relativistic effects

    Czech Academy of Sciences Publication Activity Database

    Zvára, Ivo

    1999-01-01

    Roč. 49, č. 2 (1999), s. 563-571 ISSN 0011-4626 Institutional research plan: CEZ:AV0Z1048901 Keywords : transactinoid * relativistic effects * chemical properties Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 0.328, year: 1999

  1. Solution standards for quality control of nuclear-material analytical measurements

    International Nuclear Information System (INIS)

    Clark, J.P.

    1981-01-01

    Analytical chemistry measurement control depends upon reliable solution standards. At the Savannah River Plant Control Laboratory over a thousand analytical measurements are made daily for process control, product specification, accountability, and nuclear safety. Large quantities of solution standards are required for a measurement quality control program covering the many different analytical chemistry methods. Savannah River Plant produced uranium, plutonium, neptunium, and americium metals or oxides are dissolved to prepare stock solutions for working or Quality Control Standards (QCS). Because extensive analytical effort is required to characterize or confirm these solutions, they are prepared in large quantities. These stock solutions are diluted and blended with different chemicals and/or each other to synthesize QCS that match the matrices of different process streams. The target uncertainty of a standard's reference value is 10% of the limit of error of the methods used for routine measurements. Standard Reference Materials from NBS are used according to special procedures to calibrate the methods used in measuring the uranium and plutonium standards so traceability can be established. Special precautions are required to minimize the effects of temperature, radiolysis, and evaporation. Standard reference values are periodically corrected to eliminate systematic errors caused by evaporation or decay products. Measurement control is achieved by requiring analysts to analyze a blind QCS each shift a measurement system is used on plant samples. Computer evaluation determines whether or not a measurement is within the +- 3 sigma control limits. Monthly evaluations of the QCS measurements are made to determine current bias correction factors for accountability measurements and detect significant changes in the bias and precision statistics. The evaluations are also used to plan activities for improving the reliability of the analytical chemistry measurements

  2. Physics, radiology, and chemistry. 7. rev. ed.

    International Nuclear Information System (INIS)

    Linde, O.K.; Knigge, H.J.

    1986-01-01

    This book is an introduction to physics and chemistry especially for medical personnel. After a general introduction, measurement methods, mechanics including mechanics of solid bodies, fluids and gases, heat, optics, acoustics, electricity, radiations including their biological effects, general chemistry, inorganic and organic chemistry are treated. Every chapter contains exercises mostly in connection with medical and biological effects. Furthermore, connections with biology and medicine are considered. The chapters on physiological chemistry, computer and information theory, chemistry and ecology, and metabolism have been rewritten. (orig./HP) [de

  3. The quadruple bottom line: the advantages of incorporating Green Chemistry into the undergraduate chemistry major

    Science.gov (United States)

    Bodner, George M.

    2017-08-01

    When the author first became involved with the Green Chemistry movement, he noted that his colleagues in industry who were involved in one of the ACS Green Chemistry Institute® industrial roundtables emphasized the take-home message they described as the "triple bottom line." They noted that introducing Green Chemistry in industrial settings had economic, social, and environmental benefits. As someone who first went to school at age 5, and has been "going to school" most days for 65 years, it was easy for the author to see why introducing Green Chemistry into academics had similar beneficial effects within the context of economic, social and environmental domains at the college/university level. He was prepared to understand why faculty who had taught traditional courses often saw the advantage of incorporating Green Chemistry into the courses they teach. What was not as obvious is why students who were encountering chemistry for the first time were often equally passionate about the Green Chemistry movement. Recent attention has been paid, however, to a model that brings clarity to the hitherto vague term of "relevance" that might explain why integrating Green Chemistry into the undergraduate chemistry classroom can achieve a "quadruple bottom-line" for students because of potentially positive effects of adding a domain of "relevance" to the existing economic, social, and environmental domains.

  4. Effectiveness of Case-Based Learning Instruction on Epistemological Beliefs and Attitudes Toward Chemistry

    Science.gov (United States)

    Çam, Aylin; Geban, Ömer

    2011-02-01

    The purpose of the study was to investigate the effectiveness of case-based learning instruction over traditionally designed chemistry instruction on eleventh grade students' epistemological beliefs and their attitudes toward chemistry as a school subject. The subjects of this study consisted of 63 eleventh grade students from two intact classes of an urban high school instructed with same teacher. Each teaching method was randomly assigned to one class. The experimental group received case-based learning and the control group received traditional instruction. At the experimental group, life cases were presented with small group format; at the control group, lecturing and discussion was carried out. The results showed that there was a significant difference between the experimental and control group with respect to their epistemological beliefs and attitudes toward chemistry as a school subject in favor of case-based learning method group. Thus, case base learning is helpful for development of students' epistemological beliefs and attitudes toward chemistry.

  5. Chemistry, Poetry, and Artistic Illustration: An Interdisciplinary Approach to Teaching and Promoting Chemistry

    Science.gov (United States)

    Furlan, Ping Y.; Kitson, Herbert; Andes, Cynthia

    2007-10-01

    This article describes a successful interdisciplinary collaboration among chemistry, humanities and English faculty members, who utilized poetry and artistic illustration to help students learn, appreciate, and enjoy chemistry. Students taking general chemistry classes were introduced to poetry writing and museum-type poster preparation during one class period. They were then encouraged to use their imagination and creativity to brainstorm and write chemistry poems or humors on the concepts and principles covered in the chemistry classes and artistically illustrate their original work on posters. The project, 2 3 months in length, was perceived by students as effective at helping them learn chemistry and express their understanding in a fun, personal, and creative way. The instructors found students listened to the directives because many posters were witty, clever, and eye-catching. They showed fresh use of language and revealed a good understanding of chemistry. The top posters were created by a mix of A-, B-, and C-level students. The fine art work, coupled with poetry, helped chemistry come alive on campus, providing an aesthetic presentation of materials that engaged the general viewer.

  6. Transport and retention of biochar nanoparticles in a paddy soil under environmentally-relevant solution chemistry conditions.

    Science.gov (United States)

    Chen, Ming; Wang, Dengjun; Yang, Fan; Xu, Xiaoyun; Xu, Nan; Cao, Xinde

    2017-11-01

    Land application of biochar has been increasingly recommended as a powerful strategy for carbon sequestration and soil remediation. However, the biochar particles, especially those in the nanoscale range, may migrate or carry the inherent contaminants along the soil profile, posing a potential risk to the groundwater. This study investigated the transport and retention of wood chip-derived biochar nanoparticles (NPs) in water-saturated columns packed with a paddy soil. The environmentally-relevant soil solution chemistry including ionic strength (0.10-50 mM), electrolyte type (NaCl and CaCl 2 ), and natural organic matter (0-10 mg L -1 humic acid) were tested to elucidate their effects on the biochar NPs transport. Higher mobility of biochar NPs was observed in the soil at lower ionic strengths, with CaCl 2 electrolyte being more effective than NaCl in decreasing biochar NPs transport. The retained biochar NPs in NaCl was re-entrained (∼57.7%) upon lowering transient pore-water ionic strength, indicating that biochar NPs were reversibly retained in the secondary minimum. In contrast, negligible re-entrainment of biochar NPs occurred in CaCl 2 due to the primary minimum and/or particle aggregation. Humic acid increased the mobility of biochar NPs, likely due to enhanced electrosteric repulsive interactions. The transport behaviors of biochar NPs can be well interpreted by a two-site kinetic retention model that assumes reversible retention for one site, and irreversible retention for the other site. Our findings indicated that the transport of wood chip biochar NPs is significant in the paddy soil, highlighting the importance of understanding the mobility of biochar NPs in natural soils for accurately assessing their environmental impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Climate effects of anthropogenic sulfate: Simulations from a coupled chemistry/climate model

    International Nuclear Information System (INIS)

    Chuang, C.C.; Penner, J.E.; Taylor, K.E.; Walton, J.J.

    1993-09-01

    In this paper, we use a more comprehensive approach by coupling a climate model with a 3-D global chemistry model to investigate the forcing by anthropogenic aerosol sulfate. The chemistry model treats the global-scale transport, transformation, and removal of SO 2 , DMS and H 2 SO 4 species in the atmosphere. The mass concentration of anthropogenic sulfate from fossil fuel combustion and biomass burning is calculated in the chemistry model and provided to the climate model where it affects the shortwave radiation. We also investigate the effect, with cloud nucleation parameterized in terms of local aerosol number, sulfate mass concentration and updraft velocity. Our simulations indicate that anthropogenic sulfate may result in important increases in reflected solar radiation, which would mask locally the radiative forcing from increased greenhouse gases. Uncertainties in these results will be discussed

  8. Application of the principle of supramolecular chemistry in the fields of radiochemistry and radiation chemistry

    International Nuclear Information System (INIS)

    Shen Xinghai; Chen Qingde; Gao Hongcheng

    2008-01-01

    Supramolecular chemistry, one of the front fields in chemistry, is defined as 'chemistry beyond the molecule', bearing on the organized entities of higher complexity that result from the association of two or more chemical species held together by intermolecular forces. This article focuses on the application of the principle of supramolecular chemistry in the fields of radiochemistry and radiation chemistry. The following aspects are concerned: (1) the recent progress of supramolecular chemistry; (2) the application of the principle of supramolecular chemistry and the functions of supramolecular system, i.e., recognition, assembly and translocation, in the extraction of nuclides; (3) the application of microemulsion, ionic imprinted polymers, ionic liquids and cloud point extraction in the enrichment of nuclides; (4) the radiation effect of supramolecular systems. (authors)

  9. Physics, radiology, and chemistry. 5. ed.

    International Nuclear Information System (INIS)

    Linde, O.K.; Knigge, H.J.

    1978-01-01

    This book is an introduction into physics and chemistry especially for medical personnel. After a general introduction, measurement methods, mechanics including mechanics of colid bodies, fluids and gases, heat, optics, acoustics, electricity, radiations including their biological effects, general chemistry, anorganic and organic chemistry are treated. Every chapter contains exercises mostly in connection with medical and biological effects. Futhermore connections with biology and medicine are considered. (HSI) [de

  10. Effects of dissolved calcium and magnesium ions on lead-induced stress corrosion cracking susceptibility of nuclear steam generator tubing alloy in high temperature crevice solutions

    International Nuclear Information System (INIS)

    Lu, B.T.; Tian, L.P.; Zhu, R.K.; Luo, J.L.; Lu, Y.C.

    2011-01-01

    The effects of Ca 2+ and Mg 2+ ions on the stress corrosion cracking (SCC) susceptibility of UNS N08800 are investigated using constant extension rate tensile (CERT) tests at 300 o C in simulated crevice chemistries. The presence of lead contamination in the crevice chemistries increases significantly the SCC susceptibility of the alloy. The lead-assisted SCC (PbSCC) susceptibility is reduced markedly by the addition of Ca 2+ and Mg 2+ ions into the solution and this mitigating effect is enhanced by increasing the total concentration of Ca 2+ + Mg 2+ . The CERT test results are consistent with the types of fracture surfaces shown by Scanning Electron Microscopy (SEM). There is a reasonable correlation between the SCC susceptibility and the donor densities in the anodic films in accord with the role of lead-induced passivity degradation in PbSCC.

  11. Does a Course on the History and Philosophy of Chemistry Have Any Effect on Prospective Chemistry Teachers' Perceptions? The Case of Chemistry and the Chemist

    Science.gov (United States)

    Sendur, G.; Polat, M.; Kazanci, C.

    2017-01-01

    The creative comparisons prospective chemistry teachers make about "chemistry" and the "chemist" may reflect how they perceive these concepts. In this sense, it seems important to determine which creative comparisons prospective teachers make with respect to these and how these can change after the history of chemistry is…

  12. Applications, benefits and challenges of flow chemistry

    DEFF Research Database (Denmark)

    Mitic, Aleksandar; Heintz, Søren; Ringborg, Rolf Hoffmeyer

    2013-01-01

    , environmental and manufacturing perspective. A potential solution to resolve these issues is to use flow chemistry in such processes, preferably with applications of micro-and mini-sized equipment. In addition, Process Analytical Technology (PAT) may be implemented in a very efficient way in such equipment due...

  13. The Effects of Cognitive Structure Variables on Achievement in College Chemistry

    Science.gov (United States)

    Ring, Donald G.; Novak, Joseph D.

    1971-01-01

    College freshmen chemistry students who performed best on the course examinations possessed both relevant facts and relevant subsuming concepts. This conclusion supports Ausubel's theory of learning. The presence of facts unorganized by subsumers had little facilitating effect on learning of new materials. (AL)

  14. Analytical chemistry: Principles and techniques

    International Nuclear Information System (INIS)

    Hargis, L.G.

    1988-01-01

    Although this text seems to have been intended for use in a one-semester course in undergraduate analytical chemistry, it includes the range of topics usually encountered in a two-semester introductory course in chemical analysis. The material is arranged logically for use in a two-semester course: the first 12 chapters contain the subjects most often covered in the first term, and the next 10 chapters pertain to the second (instrumental) term. Overall breadth and level of treatment are standards for an undergraduate text of this sort, and the only major omission is that of kinetic methods (which is a common omission in analytical texts). In the first 12 chapters coverage of the basic material is quite good. The emphasis on the underlying principles of the techniques rather than on specifics and design of instrumentation is welcomed. This text may be more useful for the instrumental portion of an analytical chemistry course than for the solution chemistry segment. The instrumental analysis portion is appropriate for an introductory textbook

  15. Dial-A-Decon Solution Chemistry GAP Testing

    Science.gov (United States)

    2012-04-01

    M25, Ml00, M250 , Ml000). The pipette size used was determined by the amount of extraction solution to be delivered. The analytical GC vials used...dilutions were prepared using Gilson Microman positive displacement pipettes (Gilson product numbers MIO, M25, Ml00, M250 , Ml000). The pipette size

  16. Reconsidering Learning Difficulties and Misconceptions in Chemistry: Emergence in Chemistry and Its Implications for Chemical Education

    Science.gov (United States)

    Tümay, Halil

    2016-01-01

    Identifying students' misconceptions and learning difficulties and finding effective ways of addressing them has been one of the major concerns in chemistry education. However, the chemistry education community has paid little attention to determining discipline-specific aspects of chemistry that can lead to learning difficulties and…

  17. Adsorption of Dyes in Studying the Surface Chemistry of Ultradispersed Diamond

    Science.gov (United States)

    Khokhlova, T. D.; Yunusova, G. R.; Lanin, S. N.

    2018-05-01

    The effect the surface chemistry of ultradispersed diamond (UDD) has on the adsorption of watersoluble dyes is considered. A comparison is made to adsorption on graphitized thermal carbon black (GTCB), which has a homogeneous and nonporous surface. The adsorption isotherms of dyes and the dependence of the adsorption on the pH of solutions are measured. It is found that UDD adsorbs acid (anionic) dyes—acid orange (AO) and acid anthraquinone blue (AAB)—but barely adsorbs a basic (cationic) dye, methylene blue (MB), because of the predominance of positively charged basic groups on the surface of UDD. The maximum adsorption of AO is much lower on UDD than on GTCB, while the maximum adsorption of AAB is similar for both surfaces. The adsorption of AO on UDD depends strongly on the pH of the solution, while the adsorption of AAB is independent of this parameter. It is suggested that the adsorption of AAB is determined not only by ionic and hydrophobic interactions but also by coordination interactions with impurity metal ions on a UDD surface. It is concluded that the adsorption of dyes characterizes the chemistry of a UDD surface with high sensitivity.

  18. Modelling the chemistry of iodine

    International Nuclear Information System (INIS)

    Paquette, J.

    1989-01-01

    We have assembled a kinetic model, based on elementary chemical reactions, that describes the chemical behaviour of iodine in aqueous solution as a function of time and various parameters such as pH, concentration and radiation field. The model is conceptually divided into six section: aqueous iodine chemistry, aqueous organic iodide chemistry, water radiolysis, radiolysis of iodine solutions, radiolysis of organic iodide solutions and mass transfer. The model indicates that, in the absence of a radiation field, the rate of production of volatile iodine species is controlled by the rate of oxidation of the iodide ion. The volatile iodine species are dominated by organic iodides if organic impurities are present. The single most important parameter controlling iodine volatility is the pH of the solution; high pH values tend to minimize iodine volatility. In the presence of a radiation field, the volatility of iodine is controlled by the radiation-induced oxidation of the iodide ion. Again, iodine volatility is dominated by organic iodides if organic impurities are present. High pH values minimize iodine volatility. A sensitivity analysis has been performed on some sections of the model to identify reactions to which the volatility of iodine is most sensitive. In the absence of a radiation field, the volatility is most sensitive, first, to the rate of oxidation of the iodide ion, and, second, to the rate of mass transfer of volatile species between the aqueous and the gaseous phases. This approach should be useful in identifying reactions for which accurate rate constants are required and in decreasing the complexity of the model. 37 refs

  19. Uranium chemistry in stack solutions and leachates of phosphogypsum disposed at a coastal area in Cyprus.

    Science.gov (United States)

    Lysandrou, M; Pashalidis, I

    2008-02-01

    The effect of the matrix composition (main constituents) on the concentration and chemical behavior of uranium in phosphogypsum stack solutions and leachates has been investigated. Solid and aqueous samples were taken from three different sub-areas of a phosphogypsum stack at a coastal area in Vasilikos (Cyprus). The sub-areas are characterized whether by their acidity (e.g. "aged" and "non-aged" phosphogypsum) or by their salt content, originating from pulping water during wet stacking or (after deposition) from the adjacent sea. Measurements in stack solutions and leachates showed that phosphogypsum characteristics affect both, the concentration and the chemical behavior of uranium in solution. Uranium concentration in solutions of increased salinity is up to three orders of magnitude higher than in solutions of low salinity and this is attributed to the effect of ionic strength on the solubility of phosphogypsum. Modelling showed that uranium in stack solutions is predominantly present in the form of uranium(VI) phosphate complexes (e.g. UO(2)(H(2)PO(4))(2), UO(2)HPO(4)), whereas in leachates uranium(VI) fluoro complexes (e.g. UO(2)F(2), UO(2)F(3)(-)) are predominant in solution. The latter indicates that elution of uranium from phosphogypsum takes places most probably in the form of fluoro complexes. Both, effective elution by saline water and direct migration of uranium to the sea, where it forms very stable uranium(VI) carbonato complexes, indicate that the adjacent sea will be the final receptor of uranium released from Vasilikos phosphogypsum.

  20. Problems and solutions in quantum chemistry and physics

    CERN Document Server

    Johnson, Charles S

    1988-01-01

    Unusually varied problems, with detailed solutions, cover quantum mechanics, wave mechanics, angular momentum, molecular spectroscopy, scattering theory, more. 280 problems, plus 139 supplementary exercises.

  1. Importance of nuclear power for chemistry

    International Nuclear Information System (INIS)

    Kolotyrkin, J.

    1982-01-01

    Examples are given of the use of ionizing radiations in nuclear chemistry, in radiation cross-linking of polymers. The possibilities are also indicated of applications in the disinfection of wastes, in fertilizer production and packaging, in the production of cellulose and hydrogen. The implementation of the said technologies depends on the solution of a number organizational problems. (J.B.)

  2. Effectiveness of Case-Based Learning Instruction on Pre-Service Teachers' Chemistry Motivation and Attitudes toward Chemistry

    Science.gov (United States)

    Çam, Aylin; Geban, Ömer

    2017-01-01

    Background: The development of primary pre-service teachers' chemistry motivation and attitudes toward chemistry were examined in order to develop their science literacy using case-based learning. Students' ideas were emphasized, real-life situations were discussed, and students could share their ideas and knowledge with peers; as a result,…

  3. Flipped Classroom in Organic Chemistry Has Significant Effect on Students’ Grades

    Directory of Open Access Journals (Sweden)

    Caroline Cormier

    2018-01-01

    Full Text Available The flipped classroom as a form of active pedagogy in postsecondary chemistry has been developed during the last 10 years and has been gaining popularity with instructors and students ever since. In the current paradigm in science, technology, engineering, and mathematics education, it is widely recognized that active learning has significant positive effects on students’ grades. Postsecondary organic chemistry is a difficult course for students, and the traditional way of teaching does not foster students’ active involvement. Implementation of active pedagogy could increase students’ achievement in this course. However, few quantitative data are available on the impact of active pedagogy in general, or flipped classrooms in particular, on learning in organic chemistry at a postsecondary level. Thus, in this study, we evaluated the gain on final grade scores in organic chemistry after implementing a flipped classroom approach to promote active learning in this course. We encouraged students to be active by having them watch educational videos before each class and then having them work during class time on problems that focused on applying the concepts presented in the videos. Exams were the same as those completed by students in the traditional classrooms of our college. In an a posteriori analysis of our students’ grades, we compared final grades in traditional classrooms (control group, N = 66 and in flipped classrooms (experimental group, N = 151. The sample was stratified in three categories depending on students’ academic ability in college, from low-achieving to high-achieving students. Our results show that students in the experimental group have significantly higher final grades in organic chemistry than those in the control group, that is, 77% for students in the active classroom vs. 73% in the traditional classroom (p < 0.05. The effect was the greatest for low-achieving students, with final scores of 70% in

  4. Role of Organic Solutes in the Chemistry Of Acid-Impacted Bog Waters of the Western Czech Republic

    Science.gov (United States)

    HrušKa, Jakub; Johnson, Chris E.; KráM, Pavel

    1996-04-01

    In many regions, naturally occurring organic acid anions can effectively buffer mineral acid inputs from atmospheric deposition, moderating their effect on surface water pH. We studied the effect of chronically high inputs of acid rain on the chemistry of three brown-water streams in the western Czech Republic. The dissolved organic acids in the streams were similar in character to those of other systems in Europe and North America. The site densities (the carboxyl group content per mass of C) were similar to values reported from Fenno-Scandia, and the relationship between the apparent pKa and pH conformed to those from two North American studies. Sulfate and organic acid anions (OA-) were the dominant anions in all three streams, yet despite high dissolved organic carbon and total organic acid concentrations, OA - comprised only 21-32% of total anion charge. This pattern was due to very high sulfate concentrations and, in two of the streams, a low degree of dissociation of the organic acids, probably the results of high long-term inputs of strong acids. Stream water pH was highly correlated to sulfate concentration, but uncorrelated with OA-, suggesting that free acidity is controlled by strong mineral acids rather than organic acids. Thus future reductions in strong acid inputs should result in increased pH and a return to organic control over acid-base chemistry.

  5. The changing role of chemistry in the power industry

    International Nuclear Information System (INIS)

    Caris, N.B.

    2006-01-01

    Corrosion costs the U.S. electricity industry between five and ten billion dollars a year. In steam generating plants it is estimated that over half the forced outages are caused by corrosion, and in the U.S. industry, corrosion increases the cost of electricity more than it increases the cost of any other product, adding over 10% to its price. The total cost of corrosion to U.S. industry is in excess of dollar 276 billion annually, of which more than 30% could be prevented through the use of optimum corrosion management practices. In order to effectively deal with these issues it will require a coordinated approach throughout the industry, in which chemistry has a major role to play. Chemistry has effectively moved from being a problem to being a solution for materials and corrosion issues, and judging by the current advances and initiatives, will continue to do so. The window of opportunity to positively influence the entire industry is here. This will be especially challenging for us as chemists in Eskom, with an ageing fleet and lack of excess generating capacity. The spin-off of taking up this challenge to 'get our chemistry right' and take a quantum step forward would be a significant positive effect on the unit capability factor (UCF) and the forced loss rate (UCLF) for the Generation Division. This could, in turn, influence issues as far reaching as the cost of electricity for the South African consumer and when the construction of new generating plant is scheduled. (orig.)

  6. Climate and chemistry effects of a regional scale nuclear conflict

    OpenAIRE

    Stenke A.; Hoyle C. R.; Luo B.; Rozanov E.; Groebner J.; Maag L.; Broennimann S.; Peter T.

    2013-01-01

    Previous studies have highlighted the severity of detrimental effects for life on Earth after an assumed regionally limited nuclear war. These effects are caused by climatic, chemical and radiative changes persisting for up to one decade. However, so far only a very limited number of climate model simulations have been performed, giving rise to the question how realistic previous computations have been. This study uses the coupled chemistry climate model (CCM) SOCOL, which belongs to a...

  7. Electronic structure tautomerism, and mechanism of H-D exchange in imidazole aqueous solutions

    International Nuclear Information System (INIS)

    Borisov, Yu.A.; Vorob'eva, N.P.; Abronin, I.A.; Kolomiets, A.F.

    1988-01-01

    The imidazole electronic structure in a gaseous phase is studied taking into account the influence of solvation effects in aqueous solutions. Possible mechanisms of tautomeric transformations and H-D exchange reactions with water molecules are discussed. Using the quantum chemistry methods, it is shown that the intramolecular mechanism of imidazole isomerization in the gaseous phase and the aqueous solution is unprofitable, and the intermolecular mechanism can proceed through the stage of protonated and carbene form formation

  8. Third Chemistry Conference on Recent Trends in Chemistry

    International Nuclear Information System (INIS)

    Saeed, M.M.; Wheed, S.

    2011-01-01

    The third chemistry conference 2011 on recent trends in chemistry was held from October 17-19, 2001 at Islamabad, Pakistan. More than 65 papers and oral presentation. The scope of the conference was wide open and provides and opportunity for participation of broad spectrum of chemists. This forum provided a platform for the dissemination of the latest research followed by discussion pertaining to new trends in chemistry. This con fence covered different aspects of subjects including analytical chemistry, environmental chemistry, polymer chemistry, industrial chemistry, biochemistry and nano chemistry etc. (A.B.)

  9. Effectiveness of Student-Generated Video as a Teaching Tool for an Instrumental Technique in the Organic Chemistry Laboratory

    Science.gov (United States)

    Jordan, Jeremy T.; Box, Melinda C.; Eguren, Kristen E.; Parker, Thomas A.; Saraldi-Gallardo, Victoria M.; Wolfe, Michael I.; Gallardo-Williams, Maria T.

    2016-01-01

    Multimedia instruction has been shown to serve as an effective learning aid for chemistry students. In this study, the viability of student-generated video instruction for organic chemistry laboratory techniques and procedure was examined and its effectiveness compared to instruction provided by a teaching assistant (TA) was evaluated. After…

  10. The Effect of Different Metacognitive Skill Levels on Preservice Chemistry Teachers' Motivation

    Science.gov (United States)

    Sen, Senol

    2016-01-01

    The purpose of this study was to determine the metacognitive skill levels and motivation of preservice chemistry teachers and to investigate the effect of different metacognitive skill levels on their motivation. The study was conducted during 2014-2015 spring semester. In this research, survey method was used to reveal the effect of different…

  11. Research in radiation chemistry

    International Nuclear Information System (INIS)

    Silverman, J.

    1974-01-01

    In the survey the author discusses phenomena which are unique to radiation chemistry, as well as those in which radiation chemistry research plays a principal role. Works in this field such as spur phenomena and effects of scavengers in the radiolysis of water and liquid alkane, intraspur effects in styrene and polymerization of styrene at high dose rates are presented. The problem of the missing hydrogen atoms in irradiated alkanes needs answer and sensitization of crosslinking reactions may involve some unique aspects of radiation chemistry. Pairwise trapping of radicals in irradiated n-hydrocarbons have been observed in ESP-spectra. A well defined spectrum of radical pairs when the crystals of n-eicosane is irradiated and observed at 77 deg K. The nature of the spectrum, its changes with temperature and the effect of LET is discussed in the paper. (M.S.)

  12. Enhancing prospective chemistry teachers cognitive structures in the topics of bonding and hybridization by internet-assisted chemistry applications

    OpenAIRE

    Özge Özyalçın Oskay, Sinem Dinçol

    2011-01-01

    The purpose of this study is to determine the effects of internet-assisted chemistry applications on prospective chemistry teachers’ cognitive structures in the topics of bonding and hybridization. The sample of the study consisted of 36 prospective chemistry teachers attending Hacettepe University, Faculty of Education, the Department of Chemistry Education in 2010-2011 academic year and taking Basic Chemistry I lesson. In the study, students were separated into experimental and control gr...

  13. Online Automatic Titration of Chromic Acid in Chromium Plating Solutions and Phosphoric and Sulfuric Acids in Electropolishing Solutions

    National Research Council Canada - National Science Library

    Sopok, Samuel

    1991-01-01

    .... The analytical chemistry literature lacks an adequate online automatic titration method for the monitoring of chromic acid in chromium plating solutions and the monitoring of phosphoric and sulfuric...

  14. Green Chemistry: Effect of Microwave Irradiationon Synthesis of Chitosan for Biomedical Grade Applications of Biodegradable Materials

    Directory of Open Access Journals (Sweden)

    Amri Setyawati

    2016-10-01

    Full Text Available Microwave assisted chitosan synthesis as biodegradable material for biomedical application has been done. The purpose of this research is to synthesis of chitosan with high DD and low molecular weight using microwave energy, the study of reaction conditions include parameters of power and reaction time. Chitosan was prepared by deacetylation of chitin with 60% NaOH solution. Conventional method has been done by reflux for 90minutes, resulting chitosan with DD of 79.5%, 72.6% yields and molecular weight 6051 g/mol. Green chemistry method using microwave radiation at 800 Watts for 5 minutes has produced chitosan with highest DD, yield and molecular weight of 86%, 75% and 3797 g/mole respectively. Synthesis of Chitosan by microwave radiation method can save 10x electrical energy for the reaction, also rapidly and effectively to produce chitosan with low molecular weight compared to conventional methods

  15. Plutonium(IV) hydrous polymer chemistry

    International Nuclear Information System (INIS)

    Toth, L.M.; Dodson, K.E.

    1985-01-01

    The hydrous polymer chemistry of Pu(IV) in aqueous nitric acid solutions has been a subject of considerable interest for several years. This interest stems mainly from the fact that most nuclear fuel reprocessing schemes based on the Purex process can be hampered by the occurrence of polymer. As a result, an understanding and control of the parameters that affect polymer formation during reprocessing are studied. 2 refs

  16. Hydration patterns and salting effects in sodium chloride solution.

    Science.gov (United States)

    Li, Weifeng; Mu, Yuguang

    2011-10-07

    The salting effects of 2M sodium chloride electrolyte are studied based on a series of model solutes with properties ranging from hydrophobic to hydrophilic. Generally, hydrophobic solutes will be salted out and hydrophilic solutes will be salted in by NaCl solution. The solvation free energy changes are highly correlated with Kirkwood-Buff integrals. The underlying mechanism resorts to the preferential binding of ions and water to solutes. Our results demonstrate that the salting effect not only depends on the salt's position in Hofmeister series, but also on the solutes' specifics. Taking the hydration free energies of solutes and ions as independent variables, a schematic diagram of salting effects is suggested. The resolved multifaceted salting effects rely on the sensitive balance of the tripartite interaction among solutes, ions, and water. © 2011 American Institute of Physics

  17. Radiation chemistry

    International Nuclear Information System (INIS)

    Rodgers, F.; Rodgers, M.A.

    1987-01-01

    The contents of this book include: Interaction of ionizing radiation with matter; Primary products in radiation chemistry; Theoretical aspects of radiation chemistry; Theories of the solvated electron; The radiation chemistry of gases; Radiation chemistry of colloidal aggregates; Radiation chemistry of the alkali halides; Radiation chemistry of polymers; Radiation chemistry of biopolymers; Radiation processing and sterilization; and Compound index

  18. Finite-Difference Solution for Laminar or Turbulent Boundary Layer Flow over Axisymmetric Bodies with Ideal Gas, CF4, or Equilibrium Air Chemistry

    Science.gov (United States)

    Hamilton, H. Harris, II; Millman, Daniel R.; Greendyke, Robert B.

    1992-01-01

    A computer code was developed that uses an implicit finite-difference technique to solve nonsimilar, axisymmetric boundary layer equations for both laminar and turbulent flow. The code can treat ideal gases, air in chemical equilibrium, and carbon tetrafluoride (CF4), which is a useful gas for hypersonic blunt-body simulations. This is the only known boundary layer code that can treat CF4. Comparisons with experimental data have demonstrated that accurate solutions are obtained. The method should prove useful as an analysis tool for comparing calculations with wind tunnel experiments and for making calculations about flight vehicles where equilibrium air chemistry assumptions are valid.

  19. The effects of temperature on the radiation chemistry of polymers

    International Nuclear Information System (INIS)

    Hill, D.J.T.

    1995-01-01

    The effects of high energy radiation on polymers is dependent on a number of factors. One of the most important factors is the radiolysis temperature. This paper discusses the effects of the α-transition and the other secondary transitions, as well as the ceiling and melting temperatures, on the nature of the radiolysis reactions which occur for a number of polymers. Some implications of changes in the radiation chemistry of polymers with a change in the temperature are also considered. (author)

  20. The Interaction Effects of Gender and Grade Level on Secondary School Students' Attitude towards Learning Chemistry

    Science.gov (United States)

    Heng, Chua Kah; Karpudewan, Mageswary

    2015-01-01

    This quantitative study reports the effects of gender and grade level on secondary students' attitude towards chemistry lessons. For this purpose, the Attitude towards Chemistry Lessons Scale (ATCLS) was administered to 446 secondary school students between 16-19 years old. The ATCLS consists of four different subscales: liking for chemistry…

  1. Emanation thermal analysis. Application in solid state chemistry, analytical chemistry and engineering

    International Nuclear Information System (INIS)

    Balek, V.; Tel'deshi, Yu.

    1986-01-01

    Voluminous material on application of emenation thermal analysis for investigation of solids is systematized. General concepts and historical review of development of the method are given. Methods of introduction of inert gases into solids are considered. Theoretical aspects of inert gas evolution from solids labelled by radioactive gas or its maternal isotope are stated. The methods for measuring inert gases are considered. The possibilities, limitations and perspectives of development of radiometric emanation methods for the solution of various problems of analytical chemistry and thechnology are discussed

  2. Future in actinoids coordination chemistry

    International Nuclear Information System (INIS)

    Kitazawa, Takafumi

    2006-01-01

    Actinoids coordination chemistry is concerned with spent nuclear fuel reprocessing, specifically with solid-state chemistry of nuclear fuels, separation process with radioactive substances, and geological disposal of high-level radioactive substances. In the 21st century, accumulation of minor actinides, Np, Am, Cm, and others will be realized according with the present program of nuclear energy development. The present article briefly introduces general properties of actinide elements, followed by their coordination chemistry compared with rare earths coordination chemistry. Special facility needed to treat actinoids as well as their chemistry is briefly explained, together with the specific experimental apparatus such as X-ray Absorption Fine Structure (XAFS) and time-resolved laser-induced fluorescence spectrometry (TRLFS) with synchrotron radiation facilities. The effect of coordination with actinoids in the environment chemistry is important in underground disposal of high-level radioactive wastes. For theoretical analysis of the results with actinoids chemistry, relativistic calculation is needed. (S. Ohno)

  3. Water chemistry control to meet the advanced design and operation of light water reactors

    International Nuclear Information System (INIS)

    Shirai, Hiroshi; Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Sato, Masatoshi

    2014-01-01

    Water chemistry control is one of the key technologies to establish safe and reliable operation of nuclear power plants. The road maps on R and D plans for water chemistry of nuclear power systems in Japan have been proposed along with promotion of R and D related water chemistry improvement for the advanced application of light water reactors (LWRs). The technical trends were divided into four categories, dose rate reduction, structural integrity, fuel integrity and radioactive waste reduction, and latest technical break through for each category was shown for the advanced application of LWRs. At the same time, the technical break through and the latest movements for regulation of water chemistry were introduced for each of major organizations related to nuclear engineering in the world. The conclusions were summarized as follows; 1. Water chemistry improvements might contribute to achieve the advanced application of LWRs, while water chemistry should be often changed to achieve the advanced application of LWRs. 2. Only one solution for water chemistry control was not obtained for achieving the advanced application of LWRs, but miscellaneous solutions were possible for achieving one. Optimal water chemistry control was desired for having the good practices for satisfying multi-targets at the same time and it was much affected by the plant unique systems and operational history. 3. That meant it was difficult to determine water chemistry regulation targets for achieving application of LWRs but it was necessary to prepare suitable guideline for good achievement of application of LWRs. That meant the guideline should be recommendation for good practice in the plant. 4. The water chemistry guide line should be modified along with progress of plant operation and water chemistry and related technologies. (author)

  4. Effects of selected water chemistry variables on copper pitting propagation in potable water

    International Nuclear Information System (INIS)

    Ha Hung; Taxen, Claes; Williams, Keith; Scully, John

    2011-01-01

    Highlights: → The effects of water composition on pit propagation kinetics on Cu were separated from pit initiation and stabilization using the artificial pit method in a range of dilute HCO 3 - , SO 4 2- and Cl - -containing waters. → The effective polarization and Ohmic resistance of pits were lower in SO4 2- -containing solutions and greater in Cl - -containing solutions. → Relationship between the solution composition and the corrosion product identity and morphology were found. → These, in turn controlled the corrosion product Ohmic resistance and subsequently the pit growth rate. - Abstract: The pit propagation behavior of copper (UNS C11000) was investigated from an electrochemical perspective using the artificial pit method. Pit growth was studied systematically in a range of HCO 3 - , SO 4 2- and Cl - containing-waters at various concentrations. Pit propagation was mediated by the nature of the corrosion products formed both inside and over the pit mouth (i.e., cap). Certain water chemistry concentrations such as those high in sulfate were found to promote fast pitting that could be sustained over long times at a fixed applied potential but gradually stifled in all but the lowest concentration solutions. In contrast, Cl - containing waters without sulfate ions resulted in slower pit growth and eventual repassivation. These observations were interpreted through understanding of the identity, amount and porosity of corrosion products formed inside and over pits. These factors controlled their resistive nature as characterized using electrochemical impedance spectroscopy. A finite element model (FEM) was developed which included copper oxidation kinetics, transport by migration and diffusion, Cu(I) and Cu(II) solid corrosion product formation and porosity governed by equilibrium thermodynamics and a saturation index, as well as pit current and depth of penetration. The findings of the modeling were in good agreement with artificial pit experiments

  5. Effects of Aircraft Wake Dynamics on Measured and Simulated NO(x) and HO(x) Wake Chemistry. Appendix B

    Science.gov (United States)

    Lewellen, D. C.; Lewellen, W. S.

    2001-01-01

    High-resolution numerical large-eddy simulations of the near wake of a B757 including simplified NOx and HOx chemistry were performed to explore the effects of dynamics on chemistry in wakes of ages from a few seconds to several minutes. Dilution plays an important basic role in the NOx-O3 chemistry in the wake, while a more interesting interaction between the chemistry and dynamics occurs for the HOx species. These simulation results are compared with published measurements of OH and HO2 within a B757 wake under cruise conditions in the upper troposphere taken during the Subsonic Aircraft Contrail and Cloud Effects Special Study (SUCCESS) mission in May 1996. The simulation provides a much finer grained representation of the chemistry and dynamics of the early wake than is possible from the 1 s data samples taken in situ. The comparison suggests that the previously reported discrepancy of up to a factor of 20 - 50 between the SUCCESS measurements of the [HO2]/[OH] ratio and that predicted by simplified theoretical computations is due to the combined effects of large mixing rates around the wake plume edges and averaging over volumes containing large species fluctuations. The results demonstrate the feasibility of using three-dimensional unsteady large-eddy simulations with coupled chemistry to study such phenomena.

  6. Longevity of granular iron in groundwater treatment processes: solution composition effects on reduction of organohalides and nitroaromatic compounds.

    Science.gov (United States)

    Klausen, Jörg; Vikesland, Peter J; Kohn, Tamar; Burris, David R; Ball, William P; Roberts, A Lynn

    2003-03-15

    Although granular iron permeable reactive barriers (PRBs) are increasingly employed to contain subsurface contaminants, information pertaining to system longevity is sparse. The present investigation redresses this situation by examining the long-term effects of carbonate, silica, chloride, and natural organic matter (NOM) on reactivity of Master Builders iron toward organohalides and nitroaromatic contaminants. Six columns were operated for 1100 days (approximately 4500 pore volumes) and five others for 407 days (approximately 1800 pore volumes). Nine were continuously exposed to mixtures of contaminant species, while the other two were only intermittently exposed in order to differentiate deactivation induced by water (and inorganic cosolutes) from that resulting from contaminant reduction. Contaminants investigated were trichloroethylene, 1,2,3-trichloropropane, 1,1-dichloroethane, 2-nitrotoluene, 4-nitroacetophenone, and 4-nitroanisole. Column reactivity declined substantially over the first 300 days and was dependent on the feed solution chemistry. High carbonate concentrations enhanced reactivity slightly within the first 90 days but produced poorer performance over the long term. Both silica and NOM adversely affected reactivity, while chloride evinced a somewhat mixed effect. Observed contrasts in relative reactivities suggest that trichloroethylene, 1,2,3-trichloropropane, and nitroaromatic compounds all react at different types of reactive sites. Our results indicate that differences in groundwater chemistry should be considered in the PRB design process.

  7. Relative effect of solder flux chemistry on the humidity related failures in electronics

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    Purpose - This paper aims to investigate the effect of no-clean flux chemistry with various weak organic acids (WOAs) as activators on the corrosion reliability of electronics with emphasis on the hygroscopic nature of the residue. Design/methodology/approach - The hygroscopicity of flux residue...... in the impedance measurements were observed. Practical implications - The findings are attributed to the deliquescence RH of the WOA(s) in the flux and chemistry of water-layer formation. The results show the importance of WOA type in relation to its solubility and deliquescence RH on the corrosion reliability...

  8. Hot functional test chemistry - long term experience

    International Nuclear Information System (INIS)

    Vonkova, K.; Kysela, J.; Marcinsky, M.; Martykan, M.

    2010-01-01

    Primary circuit materials undergo general corrosion in high temperature, deoxygenated, neutral or mildly alkaline solutions to form thin oxide films. These oxide layers (films) serve as protective film and mitigate the further corrosion of primary materials. Inner chromium-rich oxide layer has low cation diffusion coefficients and thus control iron and nickel transport from the metal surface to the outer layer and their dissolution into the coolant. Much less corrosion products are generated by the compact, integral and stable oxide (passivation) layer. For the latest Czech and Slovak stations commissioned (Temelin and Mochovce) a modified Hot Functional Test (HFT) chemistry was developed in the NRI Rez. Chromium rich surface layer formatted due to modified HTF chemistry ensures lower corrosion rates and radiation field formation and thus also mitigates crud formation during operation. This procedure was also designed to prepare the commissioned unit for the further proper water chemistry practise. Mochovce 1 (SK) was the first station commissioned using these recommendations in 1998. Mochovce 2 (1999) and Temelin 1 and 2 (CZ - 2000 and 2002) were subsequently commissioned using these guidelines too. The main principles of the controlled primary water chemistry applied during the hot functional tests are reviewed and importance of the water chemistry, technological and other relevant parameters is stressed regarding to the quality of the passive layer formed on the primary system surfaces. Samples from Mochovce indicated that duplex oxide layers up to 20 μm thick were produced, which were mainly magnetite substituted with nickel and chromium (e.g. 60-65% Fe, 18-28% Cr, 9-12% Ni, <1% Mn and 1-2% Si on a stainless steel primary circuit sample). Long term operation experience from both nuclear power plants are discussed in this paper. Radiation field, occupational radiation exposure and corrosion layers evolution during the first c. ten years of operation are

  9. Introduction to nuclear chemistry

    International Nuclear Information System (INIS)

    Lieser, K.H.

    1980-01-01

    The study in this book begins with the periodic system of elements (chapter 1). The physical fundamentals necessary to understand nuclear chemistry are dealt with in chapter 2. Chapter 3 and 4 treat the influence of the mass number on the chemical behaviour (isotope effect) and the isotope separation methods thus based on this effect. A main topic is studied in chapter 5, the laws of radioactive decay, a second main topic is dealt with in chapter 8, nuclear reactions. The chemical effects of nuclear reactions are treated on their own chapter 9. Radiochemical reactions which are partly closely linked to the latter are only briefly discussed in chapter 10. The following chapters discuss the various application fields of nuclear chemistry. The large apparatus indispensable for nuclear chemistry is dealt with in a special chapter (chapter 12). Chapter 15 summarizes the manifold applications. (orig.) [de

  10. Covalent-Bond Formation via On-Surface Chemistry.

    Science.gov (United States)

    Held, Philipp Alexander; Fuchs, Harald; Studer, Armido

    2017-05-02

    In this Review article pioneering work and recent achievements in the emerging research area of on-surface chemistry is discussed. On-surface chemistry, sometimes also called two-dimensional chemistry, shows great potential for bottom-up preparation of defined nanostructures. In contrast to traditional organic synthesis, where reactions are generally conducted in well-defined reaction flasks in solution, on-surface chemistry is performed in the cavity of a scanning probe microscope on a metal crystal under ultrahigh vacuum conditions. The metal first acts as a platform for self-assembly of the organic building blocks and in many cases it also acts as a catalyst for the given chemical transformation. Products and hence success of the reaction are directly analyzed by scanning probe microscopy. This Review provides a general overview of this chemistry highlighting advantages and disadvantages as compared to traditional reaction setups. The second part of the Review then focuses on reactions that have been successfully conducted as on-surface processes. On-surface Ullmann and Glaser couplings are addressed. In addition, cyclodehydrogenation reactions and cycloadditions are discussed and reactions involving the carbonyl functionality are highlighted. Finally, the first examples of sequential on-surface chemistry are considered in which two different functionalities are chemoselectively addressed. The Review gives an overview for experts working in the area but also offers a starting point to non-experts to enter into this exciting new interdisciplinary research field. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The effectiveness of process oriented guided inquiry learning to reduce alternate conceptions in secondary chemistry

    Science.gov (United States)

    Barthlow, Michelle J.

    2011-12-01

    A nonequivalent, control group, pretest-posttest design was used to investigate student achievement in secondary chemistry. This study investigated the effect of process oriented guided inquiry learning (POGIL) in high school chemistry to reduce alternate conceptions related to the particulate nature of matter versus traditional lecture pedagogy. Data were collected from chemistry students in four large high schools and analyzed using ANCOVA. The results show that POGIL pedagogy, as opposed to traditional lecture pedagogy, resulted in fewer alternate conceptions related to the particulate nature of matter. Male and female students in the POGIL group posted better posttest scores than their traditional group peers. African-American and Hispanic students in the POGIL group exhibited achievement gains consistent with Caucasian and Asian students. Further studies are needed to determine the value of POGIL to address achievement gap concerns in chemistry.

  12. Interactive effects of soil acidity and fluoride on soil solution aluminium chemistry and barley (Hordeum vulgare L.) root growth

    International Nuclear Information System (INIS)

    Manoharan, V.; Loganathan, P.; Tillman, R.W.; Parfitt, R.L.

    2007-01-01

    A greenhouse study was conducted to determine if concentrations of fluoride (F), which would be added to acid soils via P fertilisers, were detrimental to barley root growth. Increasing rates of F additions to soil significantly increased the soil solution concentrations of aluminium (Al) and F irrespective of the initial adjusted soil pH, which ranged from 4.25 to 5.48. High rates of F addition severely restricted root growth; the effect was more pronounced in the strongly acidic soil. Speciation calculations demonstrated that increasing rates of F additions substantially increased the concentrations of Al-F complexes in the soil. Stepwise regression analysis showed that it was the combination of the activities of AlF 2 1+ and AlF 2+ complexes that primarily controlled barley root growth. The results suggested that continuous input of F to soils, and increased soil acidification, may become an F risk issue in the future. - Addition of high rates of fluoride to strongly acidic soils can reduce barley root growth due to the toxicity of aluminium-fluoride complexes formed in soil solution

  13. Theoretical chemistry periodicities in chemistry and biology

    CERN Document Server

    Eyring, Henry

    1978-01-01

    Theoretical Chemistry: Periodicities in Chemistry and Biology, Volume 4 covers the aspects of theoretical chemistry. The book discusses the stably rotating patterns of reaction and diffusion; the chemistry of inorganic systems exhibiting nonmonotonic behavior; and population cycles. The text also describes the mathematical modeling of excitable media in neurobiology and chemistry; oscillating enzyme reactions; and oscillatory properties and excitability of the heart cell membrane. Selected topics from the theory of physico-chemical instabilities are also encompassed. Chemists, mechanical engin

  14. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 1 covers papers on the advances of gas phase ion chemistry. The book discusses the advances in flow tubes and the measurement of ion-molecule rate coefficients and product distributions; the ion chemistry of the earth's atmosphere; and the classical ion-molecule collision theory. The text also describes statistical methods in reaction dynamics; the state selection by photoion-photoelectron coincidence; and the effects of temperature and pressure in the kinetics of ion-molecule reactions. The energy distribution in the unimolecular decomposition of ions, as well

  15. Effect of virtual analytical chemistry laboratory on enhancing student research skills and practices

    Directory of Open Access Journals (Sweden)

    Boris Bortnik

    2017-12-01

    Full Text Available This article aims to determine the effect of a virtual chemistry laboratory on university student achievement. The article describes a model of a laboratory course that includes a virtual component. This virtual component is viewed as a tool of student pre-lab autonomous learning. It presents electronic resources designed for a virtual laboratory and outlines the methodology of e-resource application. To find out how virtual chemistry laboratory affects student scientific literacy, research skills and practices, a pedagogical experiment has been conducted. Student achievement was compared in two learning environments: traditional – in-class hands-on – learning (control group and blended learning – online learning combined with in-person learning (experimental group. The effectiveness of integrating an e-lab in the laboratory study was measured by comparing student lab reports of the two groups. For that purpose, a set of 10 criteria was developed. The experimental and control student groups were also compared in terms of test results and student portfolios. The study showed that the adopted approach blending both virtual and hands-on learning environments has the potential to enhance student research skills and practices in analytical chemistry studies.

  16. Removal of triazine-based pollutants from water by carbon nanotubes: Impact of dissolved organic matter (DOM) and solution chemistry.

    Science.gov (United States)

    Engel, Maya; Chefetz, Benny

    2016-12-01

    Adsorption of organic pollutants by carbon nanotubes (CNTs) in the environment or removal of pollutants during water purification require deep understanding of the impacts of the presence of dissolved organic matter (DOM). DOM is an integral part of environmental systems and plays a key role affecting the behavior of organic pollutants. In this study, the effects of solution chemistry (pH and ionic strength) and the presence of DOM on the removal of atrazine and lamotrigine by single-walled CNTs (SWCNTs) was investigated. The solubility of atrazine slightly decreased (∼5%) in the presence of DOM, whereas that of lamotrigine was significantly enhanced (by up to ∼70%). Simultaneous introduction of DOM and pollutant resulted in suppression of removal of both atrazine and lamotrigine, which was attributed to DOM-pollutant competition or blockage of adsorption sites by DOM. However the decrease in removal of lamotrigine was also a result of its complexation with DOM. Pre-introduction of DOM significantly reduced pollutant adsorption by the SWCNTs, whereas introduction of DOM after the pollutant resulted in the release of adsorbed atrazine and lamotrigine from the SWCNTs. These data imply that DOM exhibits higher affinity for the adsorption sites than the triazine-based pollutants. In the absence of DOM atrazine was a more effective competitor than lamotrigine for adsorption sites in SWCNTs. However, competition between pollutants in the presence of DOM revealed lamotrigine as the better competitor. Our findings help unravel the complex DOM-organic pollutant-CNT system and will aid in CNT-implementation in water-purification technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Effects of viscoelastic ophthalmic solutions on cell cultures

    Directory of Open Access Journals (Sweden)

    Madhavan Hajib

    1998-01-01

    Full Text Available The development of mild but significant inflammation probably attributable to viscoelastic ophthalmic solutions in cataract surgery was recently brought to the notice of the authors, and hence a study of the effects of these solutions available in India, on cell cultures was undertaken. We studied the effects of 6 viscoelastic ophthalmic solutions (2 sodium hyaluronate designated as A and B, and 4 hydroxypropylmethylcellulose designated as C, D, E and F on HeLa, Vero and BHK-21 cell lines in tissue culture microtitre plates using undiluted, 1:10 and 1:100 dilutions of the solutions, and in cover slip cultures using undiluted solutions. Phase contrast microscopic examination of the solutions was also done to determine the presence of floating particles. The products D and F produced cytotoxic changes in HeLa cell line and these products also showed the presence of floating particles under phase contrast microscopy. Other products did not have any adverse effects on the cell lines nor did they show floating particles. The viscoelastic ophthalmic pharmaceutical products designated D and F have cytotoxic effects on HeLa cell line which appears to be a useful cell line for testing these products for their toxicity. The presence of particulate materials in products D and F indicates that the methods used for purification of the solution are not effective.

  18. Effect of condenser water in-leakage on steam generator water chemistry

    International Nuclear Information System (INIS)

    Balakrishnan, P.V.

    1978-01-01

    Corrosive environments may be generated within steam genrators from condenser cooling water in-leakage. Theoretical as well as experimental evaluation of the aggressiveness of such environments is being carried out for the condenser-cooling waters used at CANDU-PHW nuclear power stations. Calculations have shown that highly concentrated chloride solutions - acidic in the case of sea-water in-leakage, and alkaline in the rest of the cases considered - would be produced within the steam generator. Experiments in a model boiler showed that sea-water in-leakage caused rapid corrosion of carbon steel components when only AVT (all volatile treatment) was used for water chemistry control. Use of a non-volatile reagent, as in the congruent phosphate treatment, avoided the rapid corrosion of carbon steel. On the basis of our studies, congruent phosphate treatment during sea water in-leakage appears desirable. (author)

  19. Effects of hydraulic shellfish harvesting on benthic communities and sediment chemistry 2009-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The effects of hydraulic shellfish harvesting on the ecology of biological communities and chemistry of benthic sediments were investigated through a series of...

  20. Recent development in computational actinide chemistry

    International Nuclear Information System (INIS)

    Li Jun

    2008-01-01

    Ever since the Manhattan project in World War II, actinide chemistry has been essential for nuclear science and technology. Yet scientists still seek the ability to interpret and predict chemical and physical properties of actinide compounds and materials using first-principle theory and computational modeling. Actinide compounds are challenging to computational chemistry because of their complicated electron correlation effects and relativistic effects, including spin-orbit coupling effects. There have been significant developments in theoretical studies on actinide compounds in the past several years. The theoretical capabilities coupled with new experimental characterization techniques now offer a powerful combination for unraveling the complexities of actinide chemistry. In this talk, we will provide an overview of our own research in this field, with particular emphasis on applications of relativistic density functional and ab initio quantum chemical methods to the geometries, electronic structures, spectroscopy and excited-state properties of small actinide molecules such as CUO and UO 2 and some large actinide compounds relevant to separation and environment science. The performance of various density functional approaches and wavefunction theory-based electron correlation methods will be compared. The results of computational modeling on the vibrational, electronic, and NMR spectra of actinide compounds will be briefly discussed as well [1-4]. We will show that progress in relativistic quantum chemistry, computer hardware and computational chemistry software has enabled computational actinide chemistry to emerge as a powerful and predictive tool for research in actinide chemistry. (authors)

  1. Principles of quantum chemistry

    CERN Document Server

    George, David V

    2013-01-01

    Principles of Quantum Chemistry focuses on the application of quantum mechanics in physical models and experiments of chemical systems.This book describes chemical bonding and its two specific problems - bonding in complexes and in conjugated organic molecules. The very basic theory of spectroscopy is also considered. Other topics include the early development of quantum theory; particle-in-a-box; general formulation of the theory of quantum mechanics; and treatment of angular momentum in quantum mechanics. The examples of solutions of Schroedinger equations; approximation methods in quantum c

  2. Occupational safety and health, green chemistry, and sustainability: a review of areas of convergence.

    Science.gov (United States)

    Schulte, Paul A; McKernan, Lauralynn T; Heidel, Donna S; Okun, Andrea H; Dotson, Gary Scott; Lentz, Thomas J; Geraci, Charles L; Heckel, Pamela E; Branche, Christine M

    2013-04-15

    With increasing numbers and quantities of chemicals in commerce and use, scientific attention continues to focus on the environmental and public health consequences of chemical production processes and exposures. Concerns about environmental stewardship have been gaining broader traction through emphases on sustainability and "green chemistry" principles. Occupational safety and health has not been fully promoted as a component of environmental sustainability. However, there is a natural convergence of green chemistry/sustainability and occupational safety and health efforts. Addressing both together can have a synergistic effect. Failure to promote this convergence could lead to increasing worker hazards and lack of support for sustainability efforts. The National Institute for Occupational Safety and Health has made a concerted effort involving multiple stakeholders to anticipate and identify potential hazards associated with sustainable practices and green jobs for workers. Examples of potential hazards are presented in case studies with suggested solutions such as implementing the hierarchy of controls and prevention through design principles in green chemistry and green building practices. Practical considerations and strategies for green chemistry, and environmental stewardship could benefit from the incorporation of occupational safety and health concepts which in turn protect affected workers.

  3. Quantum Chemistry, and Eclectic Mix: From Silicon Carbide to Size Consistency

    Energy Technology Data Exchange (ETDEWEB)

    Rintelman, Jamie Marie [Iowa State Univ., Ames, IA (United States)

    2004-12-19

    Chemistry is a field of great breadth and variety. It is this diversity that makes for both an interesting and challenging field. My interests have spanned three major areas of theoretical chemistry: applications, method development, and method evaluation. The topics presented in this thesis are as follows: (1) a multi-reference study of the geometries and relative energies of four atom silicon carbide clusters in the gas phase; (2) the reaction of acetylene on the Si(100)-(2x1) surface; (3) an improvement to the Effective Fragment Potential (EFP) solvent model to enable the study of reactions in both aqueous and nonaqueous solution; and (4) an evaluation of the size consistency of Multireference Perturbation Theory (MRPT). In the following section, the author briefly discusses two topics central to, and present throughout, this thesis: Multi-reference methods and Quantum Mechanics/Molecular Mechanics (QM/MM) methods.

  4. Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

    Directory of Open Access Journals (Sweden)

    Peter I. Nagy

    2014-10-01

    Full Text Available A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011 or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostatic interactions. The present review surveys the in-solution competition of the conformations with intramolecular vs. intermolecular hydrogen bonds for different types of small organic molecules. In their most stable gas-phase structure, an intramolecular hydrogen bond is possible. In a protic solution, the intramolecular hydrogen bond may disrupt in favor of two solute-solvent intermolecular hydrogen bonds. The balance of the increased internal energy and the stabilizing effect of the solute-solvent interactions regulates the new conformer composition in the liquid phase. The review additionally considers the solvent effects on the stability of simple dimeric systems as revealed from molecular dynamics simulations or on the basis of the calculated potential of mean force curves. Finally, studies of the solvent effects on the type of the intermolecular hydrogen bond (neutral or ionic in acid-base complexes have been surveyed.

  5. Proceedings of the water chemistry and materials performance conference

    International Nuclear Information System (INIS)

    Barber, D.

    1986-01-01

    The proceedings contain 11 papers dealing with primary and secondary side water chemistry in CANDU reactors, with the associated problems of activity transport and steam generator corrosion, and also with the use of decontaminating solutions. The individual papers have been abstracted separately

  6. Proceedings of the water chemistry and materials performance conference

    Energy Technology Data Exchange (ETDEWEB)

    Barber, D [ed.; Atomic Energy of Canada Ltd., Sheridan Park, ON (Canada). CANDU Operations

    1987-12-31

    The proceedings contain 11 papers dealing with primary and secondary side water chemistry in CANDU reactors, with the associated problems of activity transport and steam generator corrosion, and also with the use of decontaminating solutions. The individual papers have been abstracted separately.

  7. A Cost-Effective Two-Part Experiment for Teaching Introductory Organic Chemistry Techniques

    Science.gov (United States)

    Sadek, Christopher M.; Brown, Brenna A.; Wan, Hayley

    2011-01-01

    This two-part laboratory experiment is designed to be a cost-effective method for teaching basic organic laboratory techniques (recrystallization, thin-layer chromatography, column chromatography, vacuum filtration, and melting point determination) to large classes of introductory organic chemistry students. Students are exposed to different…

  8. The effects of polycyclic aromatic hydrocarbons on the chemistry of photodissociation regions

    NARCIS (Netherlands)

    Bakes, ELO; Tielens, AGGM

    1998-01-01

    We have investigated the effects of including polycylic aromatic hydrocarbons (PAHs) on the abundance of neutral atoms and molecules for two typical photodissociation regions (PDRs): a high-density case (the Orion complex) and a low-density case. PAHs provide a large surface area for chemistry

  9. Position paper on main areas of nuclear chemistry research and application

    International Nuclear Information System (INIS)

    2001-01-01

    Nuclear chemistry, with its specialized areas of nuclear chemistry, radiochemistry, and radiation chemistry, mainly covers these fields: basic research in nuclear chemistry; actinide chemistry; radioanalysis; nuclear chemistry in the life sciences, geosciences, and cosmic chemistry; radiotracers in technology; nuclear power technology; nuclear waste management; tritium chemistry in fusion technology, and radiation protection and radioecology. In the more than one hundred years of history of this branch of science and technology, which was opened up by the discovery of radioactivity and of the radioelements, pioneering discoveries and developments have been made in many sectors. Far beyond the confines of this area of work, they have achieved overriding importance in applications in many fields of technology and industry and in the life sciences. Research and application in nuclear chemistry continue to be highly relevant to society, ecology, and the economy, and the potential of science and technology in this field in Germany is acknowledged internationally. In the light of this vast area of activity, and against the need to maintain competence in nuclear chemistry for the use of nuclear power, irrespective of the status of this continued use in Germany, nuclear chemistry is indispensable to the solution of future problems. The Nuclear Chemistry Group of the Gesellschaft Deutscher Chemiker therefore uses this position paper to draw attention to the urgent need to keep up and further advance nuclear chemistry applications in a variety of areas of science and technology, also as a public duty of thorough education and research. (orig.) [de

  10. Evaluating the efficacy of a chemistry video game

    Science.gov (United States)

    Shapiro, Marina

    A quasi-experimental design pre-test/post-test intervention study utilizing a within group analysis was conducted with 45 undergraduate college chemistry students that investigated the effect of implementing a game-based learning environment into an undergraduate college chemistry course in order to learn if serious educational games (SEGs) can be used to achieve knowledge gains of complex chemistry concepts and to achieve increase in students' positive attitude toward chemistry. To evaluate if students learn chemistry concepts by participating in a chemistry game-based learning environment, a one-way repeated measures analysis of variance (ANOVA) was conducted across three time points (pre-test, post-test, delayed post-test which were chemistry content exams). Results showed that there was an increase in exam scores over time. The results of the ANOVA indicated a statistically significant time effect. To evaluate if students' attitude towards chemistry increased as a result of participating in a chemistry game-based learning environment a paired samples t-test was conducted using a chemistry attitudinal survey by Mahdi (2014) as the pre- and post-test. Results of the paired-samples t-test indicated that there was no significant difference in pre-attitudinal scores and post-attitudinal scores.

  11. Chemistry at the dirac point of graphene

    Science.gov (United States)

    Sarkar, Santanu

    Graphene holds great potential as an electronic material because of its excellent transport properties, which derive from its unique Fermi surface and ballistic conductance. It exhibits extremely high mobility [~250,000 cm*2/(V*s)]. Despite its extraordinary properties, the absence of a band-gap in graphene makes it unsuitable for its use as an active element in conventional field effect transistors (FETs). Another problem with pristine graphene is its lack of solution processability, which inhibits it applications in numerous fields such as printed electronics, transparent conductors, nano-biodevices, and thin film technologies involving fuel cells, capacitors and solar cells. My thesis is focused on addressing theses issue by application of covalent chemistry on graphene. We have applied the Kolbe electro-oxidation strategy to achieve an efficient quasi-reversible electrochemical grafting of the naphthylmethyl radicals to graphene. The method facilitates reversible bandgap engineering in graphene and preparation of electrochemically erasable organic dielectric films. We have discovered that the zero-band-gap electronic structure of graphene enables it to function as either the diene or the dienophile in the Diels-Alder (DA) reaction, and this versatile synthetic method offers a powerful strategy for the reversible modification of the electronic properties of graphene under very mild conditions. We show that the application of the Diels-Alder (DA) chemistry to graphene, which is capable of simultaneous formation of a pair of sp3-carbon centers (balanced divacancies) in graphene, can selectively produce DA-modified graphene FET devices with mobility between 1,000-6,000 cm2V-1s-1 (with a variable range hopping transport mechanism). Most of the covalent chemistry applied on graphene leads to the change in hybridization of graphene sp2 carbon to sp3 (destructive hybridization) and the FET devices based on such covalently modified graphene shows a drastic reduction of

  12. Problems in photoradiation effects

    International Nuclear Information System (INIS)

    Milinchuk, V.K.

    1986-01-01

    This paper discusses the most interesting photoradiation effects observed in recent years and directs attention to problems whose solution has a bearing on progress in photoradiation chemistry, and which also are significant for divisions of modern physical chemistry such as the kinetics and mechanisms of elementary processes in solid organic materials, the radiation resistance of organic materials, and aging in polymers

  13. Ions, solutes and solvents, oh my!

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Daniel David [Iowa State Univ., Ames, IA (United States)

    2009-08-01

    Modern methods in ab initio quantum mechanics have become efficient and accurate enough to study many gas-phase systems. However, chemists often work in the solution phase. The presence of solvent molecules has been shown to affect reaction mechanisms1, lower reaction energy barriers2, participate in energy transfer with the solute3 and change the physical properties of the solute4. These effects would be overlooked in simple gas phase calculations. Careful study of specific solvents and solutes must be done in order to fully understand the chemistry of the solution phase. Water is a key solvent in chemical and biological applications. The properties of an individual water molecule (a monomer) and the behavior of thousands of molecules (bulk solution) are well known for many solvents. Much is also understood about aqueous microsolvation (small clusters containing ten water molecules or fewer) and the solvation characteristics when bulk water is chosen to solvate a solute. However, much less is known about how these properties behave as the cluster size transitions from the microsolvated cluster size to the bulk. This thesis will focus on species solvated with water clusters that are large enough to exhibit the properties of the bulk but small enough to consist of fewer than one hundred solvent molecules. New methods to study such systems will also be presented.

  14. Seawater-driven forward osmosis for enriching nitrogen and phosphorous in treated municipal wastewater: effect of membrane properties and feed solution chemistry.

    Science.gov (United States)

    Xue, Wenchao; Tobino, Tomohiro; Nakajima, Fumiyuki; Yamamoto, Kazuo

    2015-02-01

    Seawater-driven forward osmosis (FO) is considered to be a novel strategy to concentrate nutrients in treated municipal wastewater for further recovery as well as simultaneous discharge of highly purified wastewater into the sea with low cost. As a preliminary test, the performance of FO membranes in concentrating nutrients was investigated by both batch experiments and model simulation approaches. With synthetic seawater as the draw solution, the dissolved organic carbon, phosphate, and ammonia in the effluent from a membrane bioreactor (MBR) treating municipal wastewater were 2.3-fold, 2.3-fold, and 2.1-fold, respectively, concentrated by the FO process with approximately 57% of water reduction. Most of the dissolved components, including trace metals in the MBR effluent, were highly retained (>80%) in the feed side, indicating high water quality of permeate to be discharged. The effect of membrane properties on the nutrient enrichment performance was investigated by comparing three types of FO membranes. Interestingly, a polyamide membrane possessing a high negative charge demonstrated a poor capability of retaining ammonia, which was hypothesized because of an ion exchange-like mechanism across the membrane prompted by the high ionic concentration of the draw solution. A feed solution pH of 7 was demonstrated to be an optimum condition for improving the overall retention of nutrients, especially for ammonia because of the pH-dependent speciation of ammonia/ammonium forms. The modeling results showed that higher than 10-fold concentrations of ammonia and phosphate are achievable by seawater-driven FO with a draw solution to feed solution volume ratio of 2:1. The enriched municipal wastewater contains nitrogen and phosphorous concentrations comparable with typical animal wastewater and anaerobic digestion effluent, which are used for direct nutrient recovery. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Deconvoluting the effects of surface chemistry and nanoscale topography: Pseudomonas aeruginosa biofilm nucleation on Si-based substrates.

    Science.gov (United States)

    Zhang, Jing; Huang, Jinglin; Say, Carmen; Dorit, Robert L; Queeney, K T

    2018-06-01

    The nucleation of biofilms is known to be affected by both the chemistry and topography of the underlying substrate, particularly when topography includes nanoscale (topography vs. chemistry is complicated by concomitant variation in both as a result of typical surface modification techniques. Analyzing the behavior of biofilm-forming bacteria exposed to surfaces with systematic, independent variation of both topography and surface chemistry should allow differentiation of the two effects. Silicon surfaces with reproducible nanotopography were created by anisotropic etching in deoxygenated water. Surface chemistry was varied independently to create hydrophilic (OH-terminated) and hydrophobic (alkyl-terminated) surfaces. The attachment and proliferation of Psuedomonas aeruginosa to these surfaces was characterized over a period of 12 h using fluorescence and confocal microscopy. The number of attached bacteria as well as the structural characteristics of the nucleating biofilm were influenced by both surface nanotopography and surface chemistry. In general terms, the presence of both nanoscale features and hydrophobic surface chemistry enhance bacterial attachment and colonization. However, the structural details of the resulting biofilms suggest that surface chemistry and topography interact differently on each of the four surface types we studied. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Proceedings of the national conference on recent trends in materials chemistry and engineering

    International Nuclear Information System (INIS)

    2011-01-01

    This national conference focuses on the latest trends in materials chemistry and engineering. Materials chemistry unites the diverse disciplines of science seamlessly and underlines the need for a collaborative research. In today's technologically advanced society, the need to extend the wealth of basic knowledge on materials to the solutions of engineering problems is great. Papers relevant to INIS are indexed separately

  17. Removal of heavy metals from aqueous solution by using mango ...

    African Journals Online (AJOL)

    user

    2011-03-14

    Mar 14, 2011 ... exchange, reverse osmosis and solvent extraction (Rich and Cherry, 1987). ... the solution chemistry of the metals, the activity of the functional groups in the .... and Zn2+ from synthetic solutions in single and binary metal solutions. ... coefficient of determination are 0.9449 and 0.9643 for. Langmiur and ...

  18. Radical chemistry of epigallocatechin gallate and its relevance to protein damage

    DEFF Research Database (Denmark)

    Hagerman, Ann E; Dean, Roger T; Davies, Michael Jonathan

    2003-01-01

    The radical chemistry of the plant polyphenolics epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were investigated using electron paramagnetic resonance spectroscopy. Radical species formed spontaneously in aqueous solutions at low pH without external oxidant and were spin stabilized...... redox potentials of EGCG and EGC varied from 1000 mV at pH 3 to 400 mV at pH 8. The polyphenolics did not produce hydroxyl radicals unless reduced metal ions such as iron(II) were added to the system. Zinc(II)-stabilized EGCG radicals were more effective protein-precipitating agents than unoxidized EGCG...

  19. The Effect of Guided-Inquiry Laboratory Experiments on Science Education Students' Chemistry Laboratory Attitudes, Anxiety and Achievement

    Science.gov (United States)

    Ural, Evrim

    2016-01-01

    The study aims to search the effect of guided inquiry laboratory experiments on students' attitudes towards chemistry laboratory, chemistry laboratory anxiety and their academic achievement in the laboratory. The study has been carried out with 37 third-year, undergraduate science education students, as a part of their Science Education Laboratory…

  20. The chemistry of salt-affected soils and waters

    Science.gov (United States)

    Knowledge of the chemistry of salt affected soils and waters is necessary for management of irrigation in arid and semi-arid regions. In this chapter we review the origin of salts in the landscape, the major chemical reactions necessary for prediction of the soil solution composition, and the use of...

  1. Bibliographies on radiation chemistry

    International Nuclear Information System (INIS)

    Hoffman, M.Z.; Ross, A.B.

    1986-01-01

    The one-electron oxidation and reduction of metal ions and complexes can yield species in unusual oxidation states, and ligand-radicals coordinated to the central metal. These often unstable species can be mechanistically important intermediates in thermal, photochemical, and electrochemical reactions involving metal-containing substances. Their generation via radiolysis provides an alternate means of characterizing them using kinetic and spectroscopic techniques. We hope these bibliographies on the radiation chemistry of metal ions and complexes, presented according to periodic groups, will prove useful to researchers in metallo-redox chemistry. These bibliographies contain only primary literature sources; reviews are not included. However, a list of general review articles on the radiation chemistry of metal ions and complexes is presented here in the first section which covers cobalt, rhodium and iridium, Group 9 in the new IUPAC notation. Additional parts of the bibliography are planned, covering other periodic groups. Part A of the bibliography was prepared by a search of the Radiation Chemistry Data Center Bibliographic Data Base (RCDCbib) through January 1986 for papers on rhodium, iridium and cobalt compounds, and radiolysis (both continuous and pulsed). Papers in which the use of metal compounds was incidental to the primary objective of the study were excluded. Excluded also were publications in unrefereed and obscure sources such as meeting proceedings, internal reports, dissertations, and patents. The majority of the studies in the resultant compilation deal with experiments performed on solutions, mainly aqueous, although a substantial fraction is devoted to solid-state esr measurements. The references are listed in separate sections for each of the metals, and are presented in approximate chronological order. (author)

  2. Effects of shutdown chemistry on steam generator radiation levels at Point Beach Unit 2. Interim report

    International Nuclear Information System (INIS)

    Kormuth, J.W.

    1982-05-01

    A refueling shutdown chemistry test was conducted at a PWR, Point Beach Unit 2. The objective was to yield reactor coolant chemistry data during the cooldown/shutdown process which might establish a relationship between shutdown chemistry and its effects on steam generator radiation fields. Of particular concern were the effects of the presence of hydrogen in the coolant as contrasted to an oxygenated coolant. Analysis of reactor coolant samples showed a rapid soluble release (spike) in Co-58, Co-60, and nickel caused by oxygenation of the coolant. The measurement of radioisotope specific activities indicates that the material undergoing dissolution during the shutdown originated from different sources which had varying histories of activation. The test program developed no data which would support theories that oxygenation of the coolant while the steam generators are full of water contributes to increased steam generator radiation levels

  3. Fine root biomass, necromass and chemistry during seven years of elevated aluminium concentrations in the soil solution of a middle-aged Picea abies stand.

    Science.gov (United States)

    Eldhuset, Toril D; Lange, Holger; de Wit, Helene A

    2006-10-01

    Toxic effects of aluminium (Al) on Picea abies (L.) Karst. (Norway spruce) trees are well documented in laboratory-scale experiments, but field-based evidence is scarce. This paper presents results on fine root growth and chemistry from a field manipulation experiment in a P. abies stand that was 45 years old when the experiment started in 1996. Different amounts of dissolved aluminium were added as AlCl3 by means of periodic irrigation during the growing season in the period 1997-2002. Potentially toxic concentrations of Al in the soil solution were obtained. Fine roots were studied from direct cores (1996) and sequential root ingrowth cores (1999, 2001, 2002) in the mineral soil (0-40 cm). We tested two hypotheses: (1) elevated concentration of Al in the root zone leads to significant changes in root biomass, partitioning into fine, coarse, living or dead fractions, and distribution with depth; (2) elevated Al concentration leads to a noticeable uptake of Al and reduced uptake of Ca and Mg; this results in Ca and Mg depletion in roots. Hypothesis 1 was only marginally supported, as just a few significant treatment effects on biomass were found. Hypothesis 2 was supported in part; Al addition led to increased root concentrations of Al in 1999 and 2002 and reduced Mg/Al in 1999. Comparison of roots from subsequent root samplings showed a decrease in Al and S over time. The results illustrated that 7 years of elevated Al(tot) concentrations in the soil solution up to 200 microM are not likely to affect root growth. We also discuss possible improvements of the experimental approach.

  4. Controls on soil solution nitrogen along an altitudinal gradient in the Scottish uplands.

    Science.gov (United States)

    Jackson-Blake, L; Helliwell, R C; Britton, A J; Gibbs, S; Coull, M C; Dawson, L

    2012-08-01

    Nitrogen (N) deposition continues to threaten upland ecosystems, contributing to acidification, eutrophication and biodiversity loss. We present results from a monitoring study aimed at investigating the fate of this deposited N within a pristine catchment in the Cairngorm Mountains (Scotland). Six sites were established along an elevation gradient (486-908 m) spanning the key habitats of temperate maritime uplands. Bulk deposition chemistry, soil carbon content, soil solution chemistry, soil temperature and soil moisture content were monitored over a 5 year period. Results were used to assess spatial variability in soil solution N and to investigate the factors and processes driving this variability. Highest soil solution inorganic N concentrations were found in the alpine soils at the top of the hillslope. Soil carbon stock, soil solution dissolved organic carbon (DOC) and factors representing site hydrology were the best predictors of NO(3)(-) concentration, with highest concentrations at low productivity sites with low DOC and freely-draining soils. These factors act as proxies for changing net biological uptake and soil/water contact time, and therefore support the hypothesis that spatial variations in soil solution NO(3)(-) are controlled by habitat N retention capacity. Soil percent carbon was a better predictor of soil solution inorganic N concentration than mass of soil carbon. NH(4)(+) was less affected by soil hydrology than NO(3)(-) and showed the effects of net mineralization inputs, particularly at Racomitrium heath and peaty sites. Soil solution dissolved organic N concentration was strongly related to both DOC and temperature, with a stronger temperature effect at more productive sites. Due to the spatial heterogeneity in N leaching potential, a fine-scale approach to assessing surface water vulnerability to N leaching is recommended over the broad scale, critical loads approach currently in use, particularly for sensitive areas. Copyright © 2012

  5. The Testing Effect: An Intervention on Behalf of Low-Skilled Comprehenders in General Chemistry

    Science.gov (United States)

    Pyburn, Daniel T.; Pazicni, Samuel; Benassi, Victor A.; Tappin, Elizabeth M.

    2014-01-01

    Past work has demonstrated that language comprehension ability correlates with general chemistry course performance with medium effect sizes. We demonstrate here that language comprehension's strong cognitive grounding can be used to inform effective and equitable pedagogies, namely, instructional interventions that differentially aid low-skilled…

  6. A Polymer "Pollution Solution" Classroom Activity.

    Science.gov (United States)

    Helser, Terry L.

    1996-01-01

    Explains an approach to presenting polymer chemistry to nonmajors that employs polystyrene foam, foam peanuts made from water soluble starch, and water soluble plastic bags. Students are presented with a pollution scenario and are guided to the discovery of solutions. (DDR)

  7. An introduction to radiation induced degradation of biological molecules in aqueous solutions

    International Nuclear Information System (INIS)

    Lal, Manohar

    1991-01-01

    Radiation chemistry of aqueous systems is the chemistry of H, OH, e aq - , H 3 O + and H 2 O * formed when a solute in aqueous solutions is exposed to ionising radiation. The pulse radiolysis technique has helped in the production, the detection and understanding of the reactions of primary species with solutes. A great deal of data on radiation biochemical studies e.g. degradation of DNA, its constituents and their protection, radiation protection and sensitisation, generation of superoxide ion and their reactions has already been reported but a great deal still needs to be done for the understanding of radiation biology. (author). 12 refs

  8. Advances in electron transfer chemistry

    CERN Document Server

    Mariano, Patrick S

    1993-01-01

    Advances in Electron Transfer Chemistry, Volume 3 presents studies that discuss findings in the various aspects of electron chemistry. The book is comprised of four chapters; each chapter reviews a work that tackles an issue in electron transfer chemistry. Chapter 1 discusses the photoinduced electron transfer in flexible biaryl donor-acceptor molecules. Chapter 2 tackles light-induced electron transfer in inorganic systems in homogeneous and heterogeneous phases. The book also covers internal geometry relaxation effects on electron transfer rates of amino-centered systems. The sequential elec

  9. Areva's water chemistry guidebook with chemistry guidelines for next generation plants (AREVA EPRTM reactors)

    International Nuclear Information System (INIS)

    Ryckelynck, N.; Chahma, F.; Caris, N.; Guillermier, P.; Brun, C.; Caron-Charles, M.; Lamanna, L.; Fandrich, J.; Jaeggy, M.; Stellwag, B.

    2012-09-01

    Over the years, AREVA globally has maintained a strong expertise in LWR water chemistry and has been focused on minimizing short-term and long-term detrimental effects of chemistry for startup, operation and shutdown chemistry for all key plant components (material integrity and reliability, promote optimal thermal performances, etc.) and fuel. Also AREVA is focused on minimizing contamination and equipment/plant dose rates. Current Industry Guidelines (EPRI, VGB, etc.) provide utilities with selected chemistry guidance for the current operating fleet. With the next generation of PWR plants (e.g. AREVA's EPR TM reactor), materials of construction and design have been optimized based on industry lessons learned over the last 50+ years. To support the next generation design, AREVA water chemistry experts, have subsequently developed a Chemistry Guidebook with chemistry guidelines based on an analysis of the current international practices, plant operating experience, R and D data and calculation codes now available and/or developed by AREVA. The AREVA LWR chemistry Guidebook can be used to help resolve utility and safety authority questions and addresses regulation requirement questions/issues for next generation plants. The Chemistry Guidebook provides water chemistry guidelines for primary coolant, secondary side circuit and auxiliary systems during startup, normal operation and shutdown conditions. It also includes conditioning and impurity limits, along with monitoring locations and frequency requirements. The Chemistry Guidebook Guidelines will be used as a design reference for AREVA's next generation plants (e.g. EPR TM reactor). (authors)

  10. Major ion chemistry of the Son River, India: Weathering processes ...

    Indian Academy of Sciences (India)

    solute flux and CDR values. The water chemistry indicates that the Son River water is good to excellent .... to separate suspended sediments and preserved at. 4◦C for further ...... and waste water, 20th edn; American Public Health. Association ...

  11. Aespoe HRL - Geoscientific evaluation 1997/4. Results from pre-investigation and detailed site characterization. Comparison of predictions and observations. Hydrogeology, groundwater chemistry and transport of solutes

    Energy Technology Data Exchange (ETDEWEB)

    Rhen, I; Gustafson, Gunnar [VBB Viak AB, Goeteborg (Sweden); Wikberg, P [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    1997-06-01

    The pre-investigations for the Aespoe Hard Rock Laboratory were started in 1986 and involved extensive field measurements, aimed at characterizing the rock formations with regard to geology, hydrogeology, hydrochemistry and rock mechanics. Prior to the excavation in 1990 predictions were made for the excavation phase concerning: geology, ground water flow and chemistry, transport of solutes and mechanical stability. This report presents a comparison between these predictions and the observations made during the excavation. Also, investigation methods for the 700-2874 m sections of the tunnel are evaluated. 157 refs, 190 figs, 37 tabs.

  12. Aespoe HRL - Geoscientific evaluation 1997/4. Results from pre-investigation and detailed site characterization. Comparison of predictions and observations. Hydrogeology, groundwater chemistry and transport of solutes

    International Nuclear Information System (INIS)

    Rhen, I.; Gustafson, Gunnar; Wikberg, P.

    1997-06-01

    The pre-investigations for the Aespoe Hard Rock Laboratory were started in 1986 and involved extensive field measurements, aimed at characterizing the rock formations with regard to geology, hydrogeology, hydrochemistry and rock mechanics. Prior to the excavation in 1990 predictions were made for the excavation phase concerning: geology, ground water flow and chemistry, transport of solutes and mechanical stability. This report presents a comparison between these predictions and the observations made during the excavation. Also, investigation methods for the 700-2874 m sections of the tunnel are evaluated

  13. Chemistry in water reactors

    International Nuclear Information System (INIS)

    Hermansson, H.P.; Norring, K.

    1994-01-01

    The international conference Chemistry in Water Reactors was arranged in Nice 24-27/04/1994 by the French Nuclear Energy Society. Examples of technical program areas were primary chemistry, operational experience, fundamental studies and new technology. Furthermore there were sessions about radiation field build-up, hydrogen chemistry, electro-chemistry, condensate polishing, decontamination and chemical cleaning. The conference gave the impression that there are some areas that are going to be more important than others during the next few years to come. Cladding integrity: Professor Ishigure from Japan emphasized that cladding integrity is a subject of great concern, especially with respect to waterside corrosion, deposition and release of crud. Chemistry control: The control of the iron/nickel concentration quotient seems to be not as important as previously considered. The future operation of a nuclear power plant is going to require a better control of the water chemistry than achievable today. One example of this is solubility control via regulation in BWR. Trends in USA: means an increasing use of hydrogen, minimization of SCC/IASCC, minimization of radiation fields by thorough chemistry control, guarding fuel integrity by minimization of cladding corrosion and minimization of flow assisted corrosion. Stellite replacement: The search for replacement materials will continue. Secondary side crevice chemistry: Modeling and practical studies are required to increase knowledge about the crevice chemistry and how it develops under plant operation conditions. Inhibitors: Inhibitors for IGSCC and IGA as well for the primary- (zinc) as for the secondary side (Ti) should be studied. The effects and mode of operation of the inhibitors should be documented. Chemical cleaning: of heat transfer surfaces will be an important subject. Prophylactic cleaning at regular intervals could be one mode of operation

  14. Selecting automation for the clinical chemistry laboratory.

    Science.gov (United States)

    Melanson, Stacy E F; Lindeman, Neal I; Jarolim, Petr

    2007-07-01

    Laboratory automation proposes to improve the quality and efficiency of laboratory operations, and may provide a solution to the quality demands and staff shortages faced by today's clinical laboratories. Several vendors offer automation systems in the United States, with both subtle and obvious differences. Arriving at a decision to automate, and the ensuing evaluation of available products, can be time-consuming and challenging. Although considerable discussion concerning the decision to automate has been published, relatively little attention has been paid to the process of evaluating and selecting automation systems. To outline a process for evaluating and selecting automation systems as a reference for laboratories contemplating laboratory automation. Our Clinical Chemistry Laboratory staff recently evaluated all major laboratory automation systems in the United States, with their respective chemistry and immunochemistry analyzers. Our experience is described and organized according to the selection process, the important considerations in clinical chemistry automation, decisions and implementation, and we give conclusions pertaining to this experience. Including the formation of a committee, workflow analysis, submitting a request for proposal, site visits, and making a final decision, the process of selecting chemistry automation took approximately 14 months. We outline important considerations in automation design, preanalytical processing, analyzer selection, postanalytical storage, and data management. Selecting clinical chemistry laboratory automation is a complex, time-consuming process. Laboratories considering laboratory automation may benefit from the concise overview and narrative and tabular suggestions provided.

  15. Isolated effects of external bath osmolality, solute concentration, and electrical charge on solute transport across articular cartilage.

    Science.gov (United States)

    Pouran, Behdad; Arbabi, Vahid; Zadpoor, Amir A; Weinans, Harrie

    2016-12-01

    The metabolic function of cartilage primarily depends on transport of solutes through diffusion mechanism. In the current study, we use contrast enhanced micro-computed tomography to determine equilibrium concentration of solutes through different cartilage zones and solute flux in the cartilage, using osteochondral plugs from equine femoral condyles. Diffusion experiments were performed with two solutes of different charge and approximately equal molecular weight, namely iodixanol (neutral) and ioxaglate (charge=-1) in order to isolate the effects of solute's charge on diffusion. Furthermore, solute concentrations as well as bath osmolality were changed to isolate the effects of steric hindrance on diffusion. Bath concentration and bath osmolality only had minor effects on the diffusion of the neutral solute through cartilage at the surface, middle and deep zones, indicating that the diffusion of the neutral solute was mainly Fickian. The negatively charged solute diffused considerably slower through cartilage than the neutral solute, indicating a large non-Fickian contribution in the diffusion of charged molecules. The numerical models determined maximum solute flux in the superficial zone up to a factor of 2.5 lower for the negatively charged solutes (charge=-1) as compared to the neutral solutes confirming the importance of charge-matrix interaction in diffusion of molecules across cartilage. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  16. Chemistry and physics

    International Nuclear Information System (INIS)

    Broerse, J.J.; Barendsen, G.W.; Kal, H.B.; Kogel, A.J. van der

    1983-01-01

    This book contains the extended abstracts of the contributions of the poster workshop sessions on chemistry and physics of the 7th international congress of radiation research. They cover the following main topics: primary processes in radiation physics and chemistry, general chemistry in radiation chemistry, DNA and model systems in radiation chemistry, molecules of biological interest in radiation chemistry, techniques in radiation chemistry, hot atom chemistry. refs.; figs.; tabs

  17. Organization of a cognitive activity of students when teaching analytical chemistry

    Directory of Open Access Journals (Sweden)

    А. Tapalova

    2012-12-01

    Full Text Available Qualitative analysis allows using basic knowledge of general and inorganic chemistry for the solution of practical problems, disclosure the chemism of the processes that are fundamental for  the methods of analysis. Systematic qualitative analysis develops analytical thinking, establishes a scientific style of thinking of students.Сhemical analysis requires certain skills and abilities and develops the general chemical culture of the future teachers оn chemistry. The result can be evaluated in the course of self-control, peer review, and solving creative problems. Mastering the techniques of critical thinking (comparison, abstraction, generalization and their use in a particular chemical material - are necessary element in the formation of professional thinking of the future chemistry teacher.

  18. Anisotropic surface chemistry properties and adsorption behavior of silicate mineral crystals.

    Science.gov (United States)

    Xu, Longhua; Tian, Jia; Wu, Houqin; Fang, Shuai; Lu, Zhongyuan; Ma, Caifeng; Sun, Wei; Hu, Yuehua

    2018-03-07

    Anisotropic surface properties of minerals play an important role in a variety of fields. With a focus on the two most intensively investigated silicate minerals (i.e., phyllosilicate minerals and pegmatite aluminosilicate minerals), this review highlights the research on their anisotropic surface properties based on their crystal structures. Four surface features comprise the anisotropic surface chemistry of minerals: broken bonds, energy, wettability, and charge. Analysis of surface broken bond and energy anisotropy helps to explain the cleavage and growth properties of mineral crystals, and understanding surface wettability and charge anisotropy is critical to the analysis of minerals' solution behavior, such as their flotation performance and rheological properties. In a specific reaction, the anisotropic surface properties of minerals are reflected in the adsorption strengths of reagents on different mineral surfaces. Combined with the knowledge of mineral crushing and grinding, a thorough understanding of the anisotropic surface chemistry properties and the anisotropic adsorption behavior of minerals will lead to the development of effective relational models comprising their crystal structure, surface chemistry properties, and targeted reagent adsorption. Overall, such a comprehensive approach is expected to firmly establish the connection between selective cleavage of mineral crystals for desired surfaces and designing novel reagents selectively adsorbed on the mineral surfaces. As tools to characterize the anisotropic surface chemistry properties of minerals, DLVO theory, atomic force microscopy (AFM), and molecular dynamics (MD) simulations are also reviewed. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Scorpion toxins prefer salt solutions

    Czech Academy of Sciences Publication Activity Database

    Nikouee, A.; Khabiri, Morteza; Cwiklik, Lukasz

    2015-01-01

    Roč. 21, č. 11 (2015), 287/1-287/14 ISSN 1610-2940 R&D Projects: GA ČR GA13-06181S Institutional support: RVO:61388963 ; RVO:61388955 Keywords : ionic solutions * molecular dynamics * nonaqueous media * secondary structure Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.438, year: 2015

  20. Ninth international symposium on hot atom chemistry. Abstracts

    International Nuclear Information System (INIS)

    1977-01-01

    Abstracts of the papers presented at the Symposium are compiled. The topics considered were chemical dynamics of high energy reactions, hot atom chemistry in organic compounds of tritium, nitrogen, oxygen, and halogens, theory and chemical dynamics of hot atom reactions as determined by beam studies, solid state reactions of recoil atoms and implanted ions, hot atom chemistry in energy-related research, hot atom chemistry in inorganic compounds of oxygen and tritium, hot positronium chemistry, applied hot atom chemistry in labelling, chemical effects of radioactive decay, decay-induced reactions and excitation labelling, physical methods in hot atom chemistry, and hot atom reactions in radiation and stratospheric chemistry

  1. Heterogeneous catalytic materials solid state chemistry, surface chemistry and catalytic behaviour

    CERN Document Server

    Busca, Guido

    2014-01-01

    Heterogeneous Catalytic Materials discusses experimental methods and the latest developments in three areas of research: heterogeneous catalysis; surface chemistry; and the chemistry of catalysts. Catalytic materials are those solids that allow the chemical reaction to occur efficiently and cost-effectively. This book provides you with all necessary information to synthesize, characterize, and relate the properties of a catalyst to its behavior, enabling you to select the appropriate catalyst for the process and reactor system. Oxides (used both as catalysts and as supports for cata

  2. Characteristics of meaningful chemistry education - The case of water quality

    NARCIS (Netherlands)

    Westbroek, Hanna Barbara

    2005-01-01

    This thesis addresses the question of how to involve students in meaningful chemistry education by a proper implementation of three characteristics of meaningful: a context, a need-to-know approach and attention for student input. The characteristics were adopted as solution strategies for

  3. The Use of Online Modules and the Effect on Student Outcomes in a High School Chemistry Class

    Science.gov (United States)

    Lamb, Richard L.; Annetta, Len

    2013-10-01

    The purpose of the study was to review the efficacy of online chemistry simulations in a high school chemistry class and provide discussion of the factors that may affect student learning. The sample consisted of 351 high school students exposed to online simulations. Researchers administered a pretest, intermediate test and posttest to measure chemistry content knowledge acquired during the use of online chemistry laboratory simulations. The authors also analyzed student journal entries as an attitudinal measure of chemistry during the simulation experience. The four analyses conducted were Repeated Time Measures Analysis of Variance, a three-way Analysis of Variance, Logistic Regression and Multiple Analysis of Variance. Each of these analyses provides for a slightly different aspect of factors regarding student attitudes and outcomes. Results indicate that there is a statistically significant main effect across grouping type (experimental versus control, p = 0.042, α = 0.05). Analysis of student journal entries suggests that attitudinal factors may affect student outcomes concerning the use of online supplemental instruction. Implications for this study show that the use of online simulations promotes increased understanding of chemistry content through open-ended and interactive questioning.

  4. Actinyl chemistry at the Centre for Radiochemistry Research

    International Nuclear Information System (INIS)

    May, Iain; Copping, Roy; Cornet, Stephanie M.; Talbot-Eeckelears, Catherine E.; Gaunt, Andrew J.; John, Gordon H.; Redmond, Mike P.; Sharrad, Clint A.; Sutton, Andrew D.; Collison, David; Fox, O. Danny; Jones, Chris J.; Sarsfield, Mark J.; Taylor, Robin J.

    2007-01-01

    Increasing our basic chemical knowledge of the actinyl cations ({AnO 2 } 2+/+ , where An = U, Np, Pu or Am) is vital for underpinning the development of novel nuclear waste management and nuclear fuel processing technologies, as well as increasing our understanding of actinide behaviour in the environment. Over recent years there have been significant advances made in uranyl, neptunyl and plutonyl chemistry, with the main focus on uranyl. At the Centre for Radiochemistry Research (CRR), University of Manchester, there are ongoing projects investigating the coordination chemistry of the actinyl cations. These projects are undertaken at the CRR and at higher specific activity alpha facilities accessed through Nexia Solutions and the EU ACTINET programme, as well as concomitant computational chemistry projects at University College London. Recent discoveries have included the complexation of transuranic actinyl cations with tri-lacunary heteropolytungstate ligands and spectroscopic and structural evidence for the direct coordination of the pertechnetate anion to {UO 2 } 2+

  5. From hot atom chemistry to epithermal chemistry

    International Nuclear Information System (INIS)

    Roessler, K.

    2004-01-01

    The rise and fall of hot atom chemistry (HAC) over the years from 1934 to 2004 is reviewed. Several applications are discussed, in particular to astrophysics and the interaction of energetic ions and atoms in space. Epithermal chemistry (ETC) is proposed to substitute the old name, since it better fits the energy range as well as the non-thermal and non-equilibrium character of the reactions. ETC also avoids the strong connexion of HAC to nuclear chemistry and stands for the opening of the field to physical chemistry and astrophysics. (orig.)

  6. Mathematical Chemistry

    OpenAIRE

    Trinajstić, Nenad; Gutman, Ivan

    2002-01-01

    A brief description is given of the historical development of mathematics and chemistry. A path leading to the meeting of these two sciences is described. An attempt is made to define mathematical chemistry, and journals containing the term mathematical chemistry in their titles are noted. In conclusion, the statement is made that although chemistry is an experimental science aimed at preparing new compounds and materials, mathematics is very useful in chemistry, among other things, to produc...

  7. Reaction chemistry of cerium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  8. RETENTION OF HUMIC ACID FROM WATER BY NANOFILTRATION MEMBRANE AND INFLUENCE OF SOLUTION CHEMISTRY ON MEMBRANE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    M. A. Zazouli, S. Nasseri, A. H. Mahvi, M. Gholami, A. R. Mesdaghinia, M. Younesian

    2008-01-01

    Full Text Available The objectives of this research were to investigate the rejection efficiency of salt and hydrophobic fraction of natural organic matter, to study the flux decline behavior with a spiral wound nanofiltration membrane, and also to survey the influence of water chemistry on membrane performance. Experiments were conducted using a cross flow pilot-scale membrane unit with a full circulation mode. Humic acid was used as hydrophobic organic matter and NaCl as background electrolyte. Results showed that flux reduction increased with increasing ionic strength and humic acid concentration, and with lower pH. The rejection efficiency of organic and salt decreased with the decrease in pH and increase in ionic strength, because of osmotic pressure increase, leading to permeate flux decline and decrease in salt rejection. In addition, the improved salt rejection was likely due to Donnan exclusion by humic material close to membrane surfaces. The average rejection efficiency of humic acid and salt ranged between 91.2%-95.25% and 63.6%-80%, respectively. Dissolved organic carbon concentration was less than 0.57mg/L in permeate for all experiments. With increasing organic concentration, the charge of the membrane surface has become more negative due to the adsorption of organic foulants on the membrane surface, and thus increased the electrostatic repulsion. However, the increasing surface charge had the potential to result in a larger molecular weight cut-off of a fouled membrane due to membrane swelling which can lead to lower rejection solutes. Therefore, results of this study indicated that membrane fouling may significantly affect the rejection of organic and ion solute.

  9. Popular Science Articles for Chemistry Teaching

    Directory of Open Access Journals (Sweden)

    Ketevan Kupatadze

    2017-07-01

    Full Text Available The presented paper reviews popular science articles (these articles are published in online magazine “The Teacher” as one of the methods of chemistry teaching. It describes which didactic principles they are in line with and how this type of articles can be used in order to kindle the interest of pupils, students and generally, the readers of other specialties, in chemistry.  The articles review the main topics of inorganic/organic chemistry, biochemistry and ecological chemistry in a simple and entertaining manner. A part of the articles is about "household" chemistry. Chemical topics are related to poetry, literature, history of chemistry or simply, to fun news. The paper delineates the structure of popular science articles and the features of engaging students. It also reviews the teachers' and students' interview results about the usage of popular science articles in chemistry teaching process. The aforementioned pedagogical study revealed that the popular science articles contain useful information not only for the students of other specialties, but also for future biologists and ecologists (having chemistry as a mandatory subject at their universities. The articles are effectively used by teachers on chemistry lessons to kindle students' interest in this subject. DOI: http://dx.doi.org/10.17807/orbital.v9i3.960 

  10. Chemistry-transport coupling and retroactive effects on material properties within the context of a deep geological repository

    International Nuclear Information System (INIS)

    Bildstein, O.

    2010-06-01

    The author gives an overview of his research and teaching activities. His researches first dealt with the development of a simulation of the chemistry/transport coupling and of the retroactive effects on transport parameters, then with the chemistry/transport modelling and its coupling with mechanics, and finally with the multi-scale investigation of porous materials. Perspectives are discussed and publications are indicated

  11. Challenges of green chemistry in Ukraine

    Directory of Open Access Journals (Sweden)

    Shevtsova Ganna Ziyvna

    2017-06-01

    Full Text Available The article deals with study of Ukrainian chemical enterprises’ ecologisation issues and elaboration of the economic problems to realize principles of green chemistry. Theoretical aspects of green chemistry as a modern interdisciplinary conception, which reveals peculiarities to implement sustainable development paradigm in the chemical industry, are studied. Based on the analysis of essence and effectiveness to introduce international initiatives on sustainable development at the chemical industry enterprises, it is concluded that the implemented measures are only first steps on the way to realize key principles of green chemistry.It is proved that in order to promote conceptual ideas of the green chemistry further, it is reasonable to consider economic and marketing aspects of the ecological innovations: to provide economic effectiveness of green chemical products and technologies, to form ecological culture of consumption, to motivate green demand and to prevent market asymmetry of information.

  12. Adsorption from solutions of non-electrolytes

    CERN Document Server

    Kipling, J J

    1965-01-01

    Adsorption from Solutions of Non-Electrolytes provides a general discussion of the subject, which has so far been given little or no attention in current textbooks of physical chemistry. A general view of the subject is particularly needed at a time when we wish to see how far it will be possible to use theories of solutions to explain the phenomena of adsorption. The book opens with an introductory chapter on the types of interface, aspects of adsorption from solution, types of adsorption, and classification of systems. This is followed by separate chapters on experimental methods, adsorption

  13. Chemistry and cosmology.

    Science.gov (United States)

    Black, John H

    2006-01-01

    The simplest elements, hydrogen and helium, offer a remarkably rich chemistry, which has controlled crucial features of the early evolution of the universe. Theoretical models of the origin of structure (stars, galaxies, clusters of galaxies, etc.) now incorporate this chemistry in some detail. In addition to the origin of structure, cosmologists are concerned with observational tests of competing world models. Primordial chemistry may give rise to some of the earliest departures from thermodynamic equilibrium in the universe. These effects may be observable as broad-band spectroscopic distortions of the cosmic background radiation, which otherwise exhibits a nearly perfect blackbody spectrum. The chemical history of the expanding universe is followed through a detailed calculation of the evolution of the abundances of H, H+, H-, H2, H2+, H3+, and other minor species. It is shown that continuous absorption by the small concentration of H- can produce a distortion in the cosmic background spectrum with a maximum at a frequency near nu/c = 9 cm-1 (wavelength 1.1 mm). The predicted effect lies only a factor of 5 below current limits. Its detection would provide an important test of our understanding of the recombination epoch of the universe.

  14. Adsorption of sodium dodecylbenzenesulfonate on activated carbons: effects of solution chemistry and presence of bacteria.

    Science.gov (United States)

    Bautista-Toledo, M I; Méndez-Díaz, J D; Sánchez-Polo, M; Rivera-Utrilla, J; Ferro-García, M A

    2008-01-01

    The objective of the present investigation was to determine the effectiveness of activated carbon in removing sodium dodecylbenzenesulfonate (SDBS) and to analyze the chemical and textural characteristics of the activated carbons that are involved in the adsorption process. Studies were also performed on the influence of operational variables (pH, ionic strength, and presence of microorganisms) and on the kinetics and interactions involved in the adsorption of this pollutant on activated carbon. The kinetics study of SDBS adsorption revealed no problems in its diffusion on any of the activated carbons studied, and Weisz-Prater coefficient (C WP) values were considerably lower than unity for all activated carbons studied. SDBS adsorption isotherms on these activated carbons showed that: (i) adsorption capacity of activated carbons was very high (260-470 mg/g) and increased with larger surface area; and (ii) dispersive interactions between SDBS and carbon surface were largely responsible for the adsorption of this pollutant. SDBS adsorption was not significantly affected by the solution pH, indicating that electrostatic adsorbent-adsorbate interactions do not play an important role in this process. The presence of electrolytes (NaCl) in the medium favors SDBS adsorption, accelerating the process and increasing adsorption capacity. Under the working conditions used, SDBS is not degraded by bacteria; however, the presence of bacteria during the process accelerates and increases SDBS adsorption on the activated carbon. Microorganism adsorption on the activated carbon surface increases its hydrophobicity, explaining the results observed.

  15. Role of Precursor-Conversion Chemistry in the Crystal-Phase Control of Catalytically Grown Colloidal Semiconductor Quantum Wires.

    Science.gov (United States)

    Wang, Fudong; Buhro, William E

    2017-12-26

    Crystal-phase control is one of the most challenging problems in nanowire growth. We demonstrate that, in the solution-phase catalyzed growth of colloidal cadmium telluride (CdTe) quantum wires (QWs), the crystal phase can be controlled by manipulating the reaction chemistry of the Cd precursors and tri-n-octylphosphine telluride (TOPTe) to favor the production of either a CdTe solute or Te, which consequently determines the composition and (liquid or solid) state of the Bi x Cd y Te z catalyst nanoparticles. Growth of single-phase (e.g., wurtzite) QWs is achieved only from solid catalysts (y ≪ z) that enable the solution-solid-solid growth of the QWs, whereas the liquid catalysts (y ≈ z) fulfill the solution-liquid-solid growth of the polytypic QWs. Factors that affect the precursor-conversion chemistry are systematically accounted for, which are correlated with a kinetic study of the composition and state of the catalyst nanoparticles to understand the mechanism. This work reveals the role of the precursor-reaction chemistry in the crystal-phase control of catalytically grown colloidal QWs, opening the possibility of growing phase-pure QWs of other compositions.

  16. PWR secondary water chemistry guidelines: Revision 3

    International Nuclear Information System (INIS)

    Lurie, S.; Bucci, G.; Johnson, L.; King, M.; Lamanna, L.; Morgan, E.; Bates, J.; Burns, R.; Eaker, R.; Ward, G.; Linnenbom, V.; Millet, P.; Paine, J.P.; Wood, C.J.; Gatten, T.; Meatheany, D.; Seager, J.; Thompson, R.; Brobst, G.; Connor, W.; Lewis, G.; Shirmer, R.; Gillen, J.; Kerns, M.; Jones, V.; Lappegaard, S.; Sawochka, S.; Smith, F.; Spires, D.; Pagan, S.; Gardner, J.; Polidoroff, T.; Lambert, S.; Dahl, B.; Hundley, F.; Miller, B.; Andersson, P.; Briden, D.; Fellers, B.; Harvey, S.; Polchow, J.; Rootham, M.; Fredrichs, T.; Flint, W.

    1993-05-01

    An effective, state-of-the art secondary water chemistry control program is essential to maximize the availability and operating life of major PWR components. Furthermore, the costs related to maintaining secondary water chemistry will likely be less than the repair or replacement of steam generators or large turbine rotors, with resulting outages taken into account. The revised PWR secondary water chemistry guidelines in this report represent the latest field and laboratory data on steam generator corrosion phenomena. This document supersedes Interim PWR Secondary Water Chemistry Recommendations for IGA/SCC Control (EPRI report TR-101230) as well as PWR Secondary Water Chemistry Guidelines--Revision 2 (NP-6239)

  17. Supramolecular chemistry-general principles and selected examples from anion recognition and metallosupramolecular chemistry.

    Science.gov (United States)

    Albrecht, Markus

    2007-12-01

    This review gives an introduction into supramolecular chemistry describing in the first part general principles, focusing on terms like noncovalent interaction, molecular recognition, self-assembly, and supramolecular function. In the second part those will be illustrated by simple examples from our laboratories. Supramolecular chemistry is the science that bridges the gap between the world of molecules and nanotechnology. In supramolecular chemistry noncovalent interactions occur between molecular building blocks, which by molecular recognition and self-assembly form (functional) supramolecular entities. It is also termed the "chemistry of the noncovalent bond." Molecular recognition is based on geometrical complementarity based on the "key-and-lock" principle with nonshape-dependent effects, e.g., solvatization, being also highly influential. Self-assembly leads to the formation of well-defined aggregates. Hereby the overall structure of the target ensemble is controlled by the symmetry features of the certain building blocks. Finally, the aggregates can possess special properties or supramolecular functions, which are only found in the ensemble but not in the participating molecules. This review gives an introduction on supramolecular chemistry and illustrates the fundamental principles by recent examples from our group.

  18. Direct and indirect effects of radiation on polar solid solutions

    International Nuclear Information System (INIS)

    Ershov, V.G.; Gaponova, I.S.

    1982-01-01

    Radiation-chemical decomposition of a solute is due to the direct effect of ionizing radiation on it and also to its reaction with radical-ion products of radiolysis of the solution. At low temperature, the movement of the reagents is limited, and thus it is possible to isolate and evaluate the contribution of direct and indirect effects of radiation on the solute. The present paper is devoted to an investigation of the mechanism of formation of radicals from a solute (LiNO 2 ) in a polar solid solution (CH 3 OH) under the effect of γ-radiation

  19. Laboratory Automatic Titration of Chromium Plating and Electropolishing Solutions

    National Research Council Canada - National Science Library

    Sopok, Samuel

    2001-01-01

    .... The analytical chemistry literature lacks an adequate automatic titration method for the monitoring of chromic acid in chromium plating solutions and the monitoring of phosphoric and sulfuric acids...

  20. Multicomponent Reactions in Ligation and Bioconjugation Chemistry.

    Science.gov (United States)

    Reguera, Leslie; Méndez, Yanira; Humpierre, Ana R; Valdés, Oscar; Rivera, Daniel G

    2018-05-25

    Multicomponent reactions (MCRs) encompass an exciting class of chemical transformations that have proven success in almost all fields of synthetic organic chemistry. These convergent procedures incorporate three or more reactants into a final product in one pot, thus combining high levels of complexity and diversity generation with low synthetic cost. Striking applications of these processes are found in heterocycle, peptidomimetic, and natural product syntheses. However, their potential in the preparation of large macro- and biomolecular constructs has been realized just recently. This Account describes the most relevant results of our group in the utilization of MCRs for ligation/conjugation of biomolecules along with significant contributions from other laboratories that validate the utility of this special class of bioconjugation process. Thus, MCRs have proven to be efficient in the ligation of lipids to peptides and oligosaccharides as well as the ligation of steroids, carbohydrates, and fluorescent and affinity tags to peptides and proteins. In the field of glycolipids, we highlight the power of isocyanide-based MCRs with the one-pot double lipidation of glycan fragments functionalized as either the carboxylic acid or amine. In peptide chemistry, the versatility of the multicomponent ligation strategy is demonstrated in both solution-phase lipidation protocols and solid-phase procedures enabling the simultaneous lipidation and biotinylation of peptides. In addition, we show that MCRs are powerful methods for synchronized lipidation/labeling and macrocyclization of peptides, thus accomplishing in one step what usually requires long sequences. In the realm of protein bioconjugation, MCRs have also proven to be effective in labeling, site-selective modification, immobilization, and glycoconjugation processes. For example, we illustrate a successful application of multicomponent polysaccharide-protein conjugation with the preparation of multivalent

  1. Improved water chemistry controls for minimizing degradation of materials

    International Nuclear Information System (INIS)

    Sawochka, S.G.

    1986-01-01

    The Electric Power Research Institute and the Steam Generator Owners Group have sponsored several efforts to develop secondary water chemistry guidelines to minimize pressurized water reactor (PWR) steam generator tubing degradation. To develop these guidelines, chemical species known to accelerate corrosion of Alloy 600 were identified, and values for normal and abnormal chemistry situations were established. For example, sodium hydroxide was known to accelerate Alloy 600 intergranular attack stress corrosion cracking; thus, guidelines were developed for blowdown sodium concentrations in recirculating steam generator systems. Similarly, formation of acidic solutions, particularly as a result of chloride ingress at seawater sites, was known to accelerate denting; thus, chloride guidelines were established. A blowdown cation conductivity limit was established to minimize concentrations of other anionic species. Guidelines also were developed for condensate and feedwater chemistry to minimize general corrosion of system materials, thereby minimizing sludge and deposit buildup in the steam generators

  2. Industrial chemistry engineering

    International Nuclear Information System (INIS)

    1993-01-01

    This book on industrial chemistry engineering is divided in two parts. The first part deals with industrial chemistry, inorganic industrial chemistry, organic industrial chemistry, analytical chemistry and practical questions. The last parts explain the chemical industry, a unit parts and thermodynamics in chemical industry and reference. It reveals the test subjects for the industrial chemistry engineering with a written examination and practical skill.

  3. Advanced chemistry management system to optimize BWR chemistry control

    International Nuclear Information System (INIS)

    Maeda, K.; Nagasawa, K.

    2002-01-01

    BWR plant chemistry control has close relationships among nuclear safety, component reliability, radiation field management and fuel integrity. Advanced technology is required to improve chemistry control [1,3,6,7,10,11]. Toshiba has developed TACMAN (Toshiba Advanced Chemistry Management system) to support BWR chemistry control. The TACMAN has been developed as response to utilities' years of requirements to keep plant operation safety, reliability and cost benefit. The advanced technology built into the TACMAN allows utilities to make efficient chemistry control and to keep cost benefit. TACMAN is currently being used in response to the needs for tools those plant chemists and engineers could use to optimize and identify plant chemistry conditions continuously. If an incipient condition or anomaly is detected at early stage, root causes evaluation and immediate countermeasures can be provided. Especially, the expert system brings numerous and competitive advantages not only to improve plant chemistry reliability but also to standardize and systematize know-how, empirical knowledge and technologies in BWR chemistry This paper shows detail functions of TACMAN and practical results to evaluate actual plant. (authors)

  4. Finite rate chemistry for USA-series codes - rormulation and applications

    International Nuclear Information System (INIS)

    Palaniswamy, S.; Chakravarthy, S.R.; Ota, D.K.

    1989-01-01

    The USA-series of CFD codes are based on unified solution algorithms including explicit and implicit formulations, factorization and relaxation approaches, time marching and space marching methodologies, etc., in order to be able to solve a very wide class of CFD problems using a single framework. Euler or Navier-Stokes equations are solved using a finite-volume treatment with upwind Total Variation Diminishing discretization for the inviscid terms. Recently, these codes have been enlarged to also unify different aerothermodynamic options (perfect gas, real gas including equilibrium and nonequlibrium chemistry). This paper describes aspects of the finite-rate-chemistry capability. 27 references

  5. The Effect of Multimedia Based Learning in Chemistry Teaching and Learning on Students’ Self-Regulated Learning

    Directory of Open Access Journals (Sweden)

    Erfan Priyambodo

    2014-11-01

    Full Text Available In recent years, the uses of Multimedia Based Learning (MBL in classroom instruction increased widely. Overall, this implementation aims to improve students’ motivation and also their learning outcomes. This study was answering the effect of MBL toward students’ Self-Regulated Learning (SRL in chemistry teaching and learning. The experiment was conducted in class XI of senior high school in Yogyakarta. Researchers create some computer based media for chemistry materials and continued with expert judgement of the media. Students’ data SRL were measured using validated questionnaire. The questionnaire consists of three components, i.e. metacognitive, motivation and behavior. The results showed that there was significant differences in SRL of students before and after participating in chemistry teaching and learning which applying MBL.

  6. Effects of barrier composition and electroplating chemistry on adhesion and voiding in copper/dielectric diffusion barrier films

    Energy Technology Data Exchange (ETDEWEB)

    Birringer, Ryan P.; Dauskardt, Reinhold H. [Department of Materials Science and Engineering, Stanford University, Durand Building, Stanford, California 94305-4034 (United States); Shaviv, Roey [Novellus Systems Inc., 4000 North First Street, San Jose, California 95134 (United States); Geiss, Roy H.; Read, David T. [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States)

    2011-08-15

    The effects of electroplating chemistry and dielectric diffusion barrier composition on copper voiding and barrier adhesion are reported. Adhesion was quantified using the four-point bend thin film adhesion technique, and voiding in the Cu films was quantified using scanning electron microscopy. A total of 12 different film stacks were investigated, including three different Cu electroplating chemistries and four different barrier materials (SiN, N-doped SiC, O-doped SiC, and dual-layer SiC). Both plating chemistry and barrier composition have a large effect on interface adhesion and voiding in the Cu film. X-ray photoelectron spectroscopy was used to investigate the segregation of Cu electroplating impurities, such as S and Cl, to the Cu/barrier interface. Secondary ion mass spectrometry was used to quantify oxygen content at the Cu/barrier interface in a subset of samples. This interface oxygen content is correlated with measured adhesion values.

  7. Green chemistry; La chimie verte

    Energy Technology Data Exchange (ETDEWEB)

    Colonna, P. [Institut National de la Recherche Agronomique, Dept. Caracterisation et Elaboration des Produits, 78 - Versailles (France)

    2006-07-01

    The depletion of world fossil fuel reserves and the involvement of greenhouse gases in the global warming has led to change the industrial and energy policies of most developed countries. The goal is now to reserve petroleum to the uses where it cannot be substituted, to implement renewable raw materials obtained from plants cultivation, and to consider the biodegradability of molecules and of manufactured objects by integrating the lifetime concept in their expected cycle of use. The green chemistry includes the design, development and elaboration of chemical products and processes with the aim of reducing or eliminating the use and generation of harmful compounds for the health and the environment, by adapting the present day operation modes of the chemical industry to the larger framework of the sustainable development. In addition to biofuels, this book reviews the applications of green chemistry in the different industrial processes in concern. Part 1 presents the diversity of the molecules coming from renewable carbon, in particular lignocellulose and the biotechnological processes. Part 2 is devoted to materials and treats of the overall available technological solutions. Part 3 focusses on functional molecules and chemical intermediates, in particular in sugar- and fats-chemistry. Part 4 treats of biofuels under the aspects of their production and use in today's technologies. The last part deals with the global approaches at the environmental and agricultural levels. (J.S.)

  8. Current organic chemistry

    National Research Council Canada - National Science Library

    1997-01-01

    Provides in depth reviews on current progress in the fields of asymmetric synthesis, organometallic chemistry, bioorganic chemistry, heterocyclic chemistry, natural product chemistry, and analytical...

  9. Aquatic Chemistry

    International Nuclear Information System (INIS)

    Kim, Dong Yeun; Kim, Oh Sik; Kim, Chang Guk; Park, Cheong Gil; Lee, Gwi Hyeon; Lee, Cheol Hui

    1987-07-01

    This book deals aquatic chemistry, which treats water and environment, chemical kinetics, chemical balance like dynamical characteristic, and thermodynamics, acid-base chemistry such as summary, definition, kinetics, and PH design for mixture of acid-base chemistry, complex chemistry with definition, and kinetics, precipitation and dissolution on summary, kinetics of precipitation and dissolution, and balance design oxidation and resolution with summary, balance of oxidation and resolution.

  10. Combinatorial chemistry

    DEFF Research Database (Denmark)

    Nielsen, John

    1994-01-01

    An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds.......An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds....

  11. Forensic Chemistry

    Science.gov (United States)

    Bell, Suzanne

    2009-07-01

    Forensic chemistry is unique among chemical sciences in that its research, practice, and presentation must meet the needs of both the scientific and the legal communities. As such, forensic chemistry research is applied and derivative by nature and design, and it emphasizes metrology (the science of measurement) and validation. Forensic chemistry has moved away from its analytical roots and is incorporating a broader spectrum of chemical sciences. Existing forensic practices are being revisited as the purview of forensic chemistry extends outward from drug analysis and toxicology into such diverse areas as combustion chemistry, materials science, and pattern evidence.

  12. Effects of ion concentration on the hydrogen bonded structure of ...

    Indian Academy of Sciences (India)

    WINTEC

    Effects of ion concentration on the hydrogen bonded structure of water in the vicinity of ions in aqueous NaCl solutions. A NAG. 1. , D CHAKRABORTY and A CHANDRA*. Department of Chemistry, Indian Institute of Technology, Kanpur 208 016. 1. Present address: Department of Chemistry and Chemical Engineering,.

  13. Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

    International Nuclear Information System (INIS)

    Ryan, R.R.

    1981-05-01

    This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research

  14. Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, R.R. (comp.)

    1981-05-01

    This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research.

  15. Connecting biology and organic chemistry introductory laboratory courses through a collaborative research project.

    Science.gov (United States)

    Boltax, Ariana L; Armanious, Stephanie; Kosinski-Collins, Melissa S; Pontrello, Jason K

    2015-01-01

    Modern research often requires collaboration of experts in fields, such as math, chemistry, biology, physics, and computer science to develop unique solutions to common problems. Traditional introductory undergraduate laboratory curricula in the sciences often do not emphasize connections possible between the various disciplines. We designed an interdisciplinary, medically relevant, project intended to help students see connections between chemistry and biology. Second term organic chemistry laboratory students designed and synthesized potential polymer inhibitors or inducers of polyglutamine protein aggregation. The use of novel target compounds added the uncertainty of scientific research to the project. Biology laboratory students then tested the novel potential pharmaceuticals in Huntington's disease model assays, using in vitro polyglutamine peptide aggregation and in vivo lethality studies in Drosophila. Students read articles from the primary literature describing the system from both chemical and biological perspectives. Assessment revealed that students emerged from both courses with a deeper understanding of the interdisciplinary nature of biology and chemistry and a heightened interest in basic research. The design of this collaborative project for introductory biology and organic chemistry labs demonstrated how the local interests and expertise at a university can be drawn from to create an effective way to integrate these introductory courses. Rather than simply presenting a series of experiments to be replicated, we hope that our efforts will inspire other scientists to think about how some aspect of authentic work can be brought into their own courses, and we also welcome additional collaborations to extend the scope of the scientific exploration. © 2015 The International Union of Biochemistry and Molecular Biology.

  16. Does leaf chemistry differentially affect breakdown in tropical vs temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Science.gov (United States)

    Marcelo Ard& #243; n; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to measure leaf chemistry. We used standardized analytical techniques to measure chemistry and breakdown rate of leaves from common riparian tree species at 2 sites, 1...

  17. Apparatus for ground water chemistry investigations in field caissons

    International Nuclear Information System (INIS)

    Cokal, E.J.; Stallings, E.; Walker, R.; Nyhan, J.W.; Polzer, W.L.; Essington, E.H.

    1985-01-01

    Los Alamos is currently in its second season of ground water chemistry and hydrology experimentation in a field facility that incorporates clusters of six, 3-meter-diameter by 6-meter-deep, soil-filled caissons and required ancillaries. Initial experience gained during the 1983 field season indicated the need for further development of the technology of this type of experimentation supporting hydrologic waste management research. Uniform field application of water/matrix solutions to the caisson, matrix and tracer solution blending/storage, and devices for ground water sampling are discussed

  18. The Brazilian medicinal chemistry from 1998 to 2008 in the Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters and European Journal of Medicinal Chemistry [A química medicinal brasileira de 1998 a 2008 nos periódicos Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters e European Journal of Medicinal Chemistry

    OpenAIRE

    Bárbara Vasconcellos da Silva; Renato Saldanha Bastos; Angelo da Cunha Pinto

    2009-01-01

    In this article we present the Brazilian publications, the research groups involved, the contributions per states and the main diseases studied from 1998 to 2008 in the following periodicals: Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters and European Journal of Medicinal Chemistry.

  19. Quantum mechanical study of solvent effects in a prototype SN2 reaction in solution: Cl- attack on CH3Cl.

    Science.gov (United States)

    Kuechler, Erich R; York, Darrin M

    2014-02-07

    The nucleophilic attack of a chloride ion on methyl chloride is an important prototype SN2 reaction in organic chemistry that is known to be sensitive to the effects of the surrounding solvent. Herein, we develop a highly accurate Specific Reaction Parameter (SRP) model based on the Austin Model 1 Hamiltonian for chlorine to study the effects of solvation into an aqueous environment on the reaction mechanism. To accomplish this task, we apply high-level quantum mechanical calculations to study the reaction in the gas phase and combined quantum mechanical/molecular mechanical simulations with TIP3P and TIP4P-ew water models and the resulting free energy profiles are compared with those determined from simulations using other fast semi-empirical quantum models. Both gas phase and solution results with the SRP model agree very well with experiment and provide insight into the specific role of solvent on the reaction coordinate. Overall, the newly parameterized SRP Hamiltonian is able to reproduce both the gas phase and solution phase barriers, suggesting it is an accurate and robust model for simulations in the aqueous phase at greatly reduced computational cost relative to comparably accurate ab initio and density functional models.

  20. Visualization of Problem Solving Related to the Quantitative Composition of Solutions in the Dynamic "GeoGebra" Environment

    Science.gov (United States)

    Kostic, V. Dj.; Jovanovic, V. P. Stankov; Sekulic, T. M.; Takaci, Dj. B.

    2016-01-01

    Problem solving in the field of quantitative composition of solutions (QCS), expressed as mass share and molar concentration, is essential for chemistry students. Since successful chemistry education is based on different mathematical contents, it is important to be proficient in both mathematical and chemistry concepts as well as interconnections…

  1. Advisory Council on College Chemistry Newsletter Number 16.

    Science.gov (United States)

    Advisory Council on Coll. Chemistry.

    Discussed are the goals of the Advisory Council on College Chemistry and the effect on College Chemistry of termination of National Science Foundation funding. Reported are conferences on (1) the relevance of thermodynamics to chemists and engineers and its place in a chemistry curriculum, (2) new approaches to teaching thermodynamics in an…

  2. Effect of fullerenol surface chemistry on nanoparticle binding-induced protein misfolding

    Science.gov (United States)

    Radic, Slaven; Nedumpully-Govindan, Praveen; Chen, Ran; Salonen, Emppu; Brown, Jared M.; Ke, Pu Chun; Ding, Feng

    2014-06-01

    Fullerene and its derivatives with different surface chemistry have great potential in biomedical applications. Accordingly, it is important to delineate the impact of these carbon-based nanoparticles on protein structure, dynamics, and subsequently function. Here, we focused on the effect of hydroxylation -- a common strategy for solubilizing and functionalizing fullerene -- on protein-nanoparticle interactions using a model protein, ubiquitin. We applied a set of complementary computational modeling methods, including docking and molecular dynamics simulations with both explicit and implicit solvent, to illustrate the impact of hydroxylated fullerenes on the structure and dynamics of ubiquitin. We found that all derivatives bound to the model protein. Specifically, the more hydrophilic nanoparticles with a higher number of hydroxyl groups bound to the surface of the protein via hydrogen bonds, which stabilized the protein without inducing large conformational changes in the protein structure. In contrast, fullerene derivatives with a smaller number of hydroxyl groups buried their hydrophobic surface inside the protein, thereby causing protein denaturation. Overall, our results revealed a distinct role of surface chemistry on nanoparticle-protein binding and binding-induced protein misfolding.Fullerene and its derivatives with different surface chemistry have great potential in biomedical applications. Accordingly, it is important to delineate the impact of these carbon-based nanoparticles on protein structure, dynamics, and subsequently function. Here, we focused on the effect of hydroxylation -- a common strategy for solubilizing and functionalizing fullerene -- on protein-nanoparticle interactions using a model protein, ubiquitin. We applied a set of complementary computational modeling methods, including docking and molecular dynamics simulations with both explicit and implicit solvent, to illustrate the impact of hydroxylated fullerenes on the structure and

  3. Effect of garlic solution to Bacillus sp. removal

    Science.gov (United States)

    Zainol, N.; Rahim, S. R.

    2018-04-01

    Biofilm is a microbial derived sessile community characterized by cells that are irreversibly attached to a substratum or interface to each other, embedded in a matrix of extracellular polymeric substances that they have produced. Bacillus sp. was used as biofilm model in this study. The purpose of this study is to determine the effect of Garlic solution in term of ratio of water and Garlic solution (W/G) and ratio of Garlic solution to Bacillus sp. (GS/B) on Bacillus sp removal. Garlic solution was used to remove Bacillus sp. In this study, Garlic solution was prepared by crushing the garlic and mixed it with water. the Garlic solution was added into Bacillus sp. mixture and mixed well. The mixture then was spread on nutrient agar. The Bacillus sp. weight on agar plate was measured by using dry weight measurement method. In this study, initially Garlic solution volume and Garlic solution concentration were studied using one factor at time (OFAT). Later two-level-factorial analysis was done to determine the most contributing factor in Bacillus sp. removal. Design Expert software (Version 7) was used to construct experimental table where all the factors were randomized. Bacilus sp removal was ranging between 42.13% to 99.6%. The analysis of the results showed that at W/G of 1:1, Bacillus sp. removal increased when more Garlic solution was added to Bacillus sp. Effect of Garlic solution to Bacillus sp. will be understood which in turn may be beneficial for the industrial purpose.

  4. Green Chemistry Techniques for Gold Nanoparticles Synthesis

    Science.gov (United States)

    Cannavino, Sarah A.; King, Christy A.; Ferrara, Davon W.

    Gold nanoparticles (AuNPs) are often utilized in many technological and research applications ranging from the detection of tumors, molecular and biological sensors, and as nanoantennas to probe physical processes. As these applications move from the research laboratory to industrial settings, there is a need to develop efficient and sustainable synthesis techniques. Recent research has shown that several food products and beverages containing polyphenols, a common antioxidant, can be used as reducing agents in the synthesis of AuNPs in solution. In this study, we explore a variety of products to determine which allow for the most reproducible solution of nanoparticles based on the size and shapes of particles present. We analyzed the AuNPs solutions using extinction spectroscopy and atomic force microscopy. We also develop a laboratory activity to introduce introductory chemistry and physics students to AuNP synthesis techniques and analysis.

  5. Large-scale separation of single-walled carbon nanotubes by electronic type using click chemistry

    Science.gov (United States)

    Um, Jo-Eun; Song, Sun Gu; Yoo, Pil J.; Song, Changsik; Kim, Woo-Jae

    2018-01-01

    Single-walled carbon nanotubes (SWCNTs) can be either metallic or semiconducting, making their separation critical for applications in nanoelectronics, biomedical materials, and solar cells. Herein, we investigate a novel solution-phase separation method based on click chemistry (azide-alkyne Huisgen cycloaddition) and determine its efficiency and scalability. In this method, metallic SWCNTs in metallic/semiconducting SWCNT mixtures are selectively functionalized with alkyne groups by being reacted with 4-propargyloxybenezenediazonium tetrafluoroborate. Subsequently, silica nanoparticles are functionalized with azide groups and reacted with alkyne-bearing metallic SWCNTs in the SWCNT mixture in the presence of a Cu catalyst. As a result, metallic SWCNTs are anchored on silica powder, whereas non-functionalized semiconducting SWCNTs remain in solution. Low-speed centrifugation effectively removes the silica powder with attached metallic SWCNTs, furnishing a solution of highly pure semiconducting SWCNTs, as confirmed by Raman and UV-vis/near-infrared absorption measurements. This novel separation scheme exhibits the advantage of simultaneously separating both metallic and semiconducting SWCNTs from their mixtures, being cost-effective and therefore applicable at an industrial scale.

  6. EPR Studies of Spin-Spin Exchange Processes: A Physical Chemistry Experiment.

    Science.gov (United States)

    Eastman, Michael P.

    1982-01-01

    Theoretical background, experimental procedures, and analysis of experimental results are provided for an undergraduate physical chemistry experiment on electron paramagnetic resonance (EPR) linewidths. Source of line broadening observed in a spin-spin exchange process between radicals formed in aqueous solutions of potassium peroxylamine…

  7. Bad chemistry

    OpenAIRE

    Petsko, Gregory A

    2004-01-01

    General chemistry courses haven't changed significantly in forty years. Because most basic chemistry students are premedical students, medical schools have enormous influence and could help us start all over again to create undergraduate chemistry education that works.

  8. Some applications of radiation chemistry to biochemistry and radiobiology

    International Nuclear Information System (INIS)

    Wardman, P.

    1987-01-01

    In this chapter illustrate the use of radiation chemistry as a tool in investigating biologically important radical reactions, and also outline some studies of models for radiobiological damage. Because aqueous solutions usually offer the most important matrix, an appreciation of the main features of water radiolysis will be essential. Most of the illustrations involve pulse radiolysis, and some familiarity with chemical kinetics is assumed. In addition to these and other chapters in this book, readers find the proceedings of a recent NATO Advanced Study Institute most useful. The authors shall not try to review here all the applications of radiation chemistry to biochemistry and biology, but they will illustrate, using selected examples, the main principles and practical advantages and problems. Another recent volume covers the main contributions of flash photolysis and pulse radiolysis to the chemistry of biology and medicine, complementing earlier reviews. Papers from symposia on radical processes in radiobiology and carcinogenesis, and on super-oxide dismutases, and proceedings of recent international congresses of radiation research, together with the other publications referred to above will enable the reader to gain a comprehensive overview of the role of radicals in biological processes and the contributions of radiation chemistry

  9. Variability in chemistry of surface and soil waters of an ...

    African Journals Online (AJOL)

    2017-01-01

    Jan 1, 2017 ... processing in the Okavango Delta, Botswana. Keotshephile ... 4Climate System Analysis Group, University of Cape Town, South Africa ... input and final fate of solutes is of critical ecological importance ... a wetland system therefore requires an in-depth understanding of the water chemistry of that system.

  10. A gluon cluster solution of effective Yang-Mills theory

    CERN Document Server

    Pavlovsky, O V

    2001-01-01

    A classical solution of the effective Yang-Mills (YM) theory with a finite energy and nonstandard Lagrangian was obtained. Influence of vacuum polarization on gluon cluster formation was discussed. Appearance of cluster solutions in the theory of non-Abelian fields can take place only if the result goes beyond the framework of pure YM theory. It is shown that account of quantum effects of polarized vacuum in the presence of a classical gluon field can also result in formation of the solutions. Solutions with the finite intrinsic energy are provided. Besides, fields of colour groups SU(2) were studied

  11. Understanding `green chemistry' and `sustainability': an example of problem-based learning (PBL)

    Science.gov (United States)

    Günter, Tuğçe; Akkuzu, Nalan; Alpat, Şenol

    2017-10-01

    Background: This study uses problem-based learning (PBL) to ensure that students comprehend the significance of green chemistry better by experiencing the stages of identifying the problem, developing hypotheses, and providing solutions within the problem-solving process.

  12. Investigating the Effectiveness of Teaching Methods Based on a Four-Step Constructivist Strategy

    Science.gov (United States)

    Çalik, Muammer; Ayas, Alipaşa; Coll, Richard K.

    2010-02-01

    This paper reports on an investigation of the effectiveness an intervention using several different methods for teaching solution chemistry. The teaching strategy comprised a four-step approach derived from a constructivist view of learning. A sample consisting of 44 students (18 boys and 26 girls) was selected purposively from two different Grade 9 classes in the city of Trabzon, Turkey. Data collection employed a purpose-designed `solution chemistry concept test', consisting of 17 items, with the quantitative data from the survey supported by qualitative interview data. The findings suggest that using different methods embedded within the four-step constructivist-based teaching strategy enables students to refute some alternative conceptions, but does not completely eliminate student alternative conceptions for solution chemistry.

  13. The Effect of Aqueous Alteration in Antarctic Carbonaceous Chondrites from Comparative ICP-MS Bulk Chemistry

    Science.gov (United States)

    Alonso-Azcarate, J.; Trigo-Rodriguez, J. M.; Moyano-Cambero, C. E.; Zolensky, M.

    2014-01-01

    Terrestrial ages of Antarctic carbonaceous chondrites (CC) indicate that these meteorites have been preserved in or on ice for, at least, tens of thousands of years. Due to the porous structure of these chondrites formed by the aggregation of silicate-rich chondrules, refractory inclusions, metal grains, and fine-grained matrix materials, the effect of pervasive terrestrial water is relevant. Our community defends that pristine CC matrices are representing samples of scarcely processed protoplanetary disk materials as they contain stellar grains, but they might also trace parent body processes. It is important to study the effects of terrestrial aqueous alteration in promoting bulk chemistry changes, and creating distinctive alteration minerals. Particularly because it is thought that aqueous alteration has particularly played a key role in some CC groups in modifying primordial bulk chemistry, and homogenizing the isotopic content of fine-grained matrix materials. Fortunately, the mineralogy produced by parent-body and terrestrial aqueous alteration processes is distinctive. With the goal to learn more about terrestrial alteration in Antarctica we are obtaining reflectance spectra of CCs, but also performing ICP-MS bulk chemistry of the different CC groups. A direct comparison with the mean bulk elemental composition of recovered falls might inform us on the effects of terrestrial alteration in finds. With such a goal, in the current work we have analyzed some members representative of CO and CM chondrite groups.

  14. Positronium chemistry

    CERN Document Server

    Green, James

    1964-01-01

    Positronium Chemistry focuses on the methodologies, reactions, processes, and transformations involved in positronium chemistry. The publication first offers information on positrons and positronium and experimental methods, including mesonic atoms, angular correlation measurements, annihilation spectra, and statistical errors in delayed coincidence measurements. The text then ponders on positrons in gases and solids. The manuscript takes a look at the theoretical chemistry of positronium and positronium chemistry in gases. Topics include quenching, annihilation spectrum, delayed coincidence

  15. Advanced chemistry management system for nuclear power plants

    International Nuclear Information System (INIS)

    Maeda, Katsuji; Kobayashi, Yasuhiro; Nagasawa, Katsumi

    2000-01-01

    Chemistry control in a boiling water reactor (BWR) plant has a close relationship with radiation field buildup, fuel reliability, integrity of plant components and materials, performance of the water treatment systems and radioactive waste generation. Chemistry management in BWR plants has become more important in order to maintain and enhance plant reliability. Adequate chemistry control and management are also essential to establish, maintain, and enhance plant availability. For these reasons, we have developed the advanced chemistry management system for nuclear power plants in order to effectively collect and evaluate a large number of plant operating and chemistry data. (author)

  16. Outline of investigation on restraint of carbon dioxide generation by green chemistry. 1999.1-1999.3; 1998 nendo green chemistry ni yoru CO2 hassei yokusei ni kakawaru chosa kenkyu chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Investigations were conducted into the above in some leading OECD (Organization for Economic Cooperation and Development) member states. Green chemistry is a new concept in which clean technology, environment-friendly chemistry, and the like are combined, and is a chemical solution for reducing or stopping the use or generation of materials, products, by-products, solvents, reagents, etc., which are dangerous to health and environments, throughout the whole life cycle of chemicals covering the processes of their designing, manufacturing, dumping, and recycling. In this fiscal year, the actual state of the generation of biomass, regarded as representative of reproducible materials, and its feasibility as chemical resources were investigated. In an effort at finding out chemical reactions safer to health and causing less environmental impact, investigations were also conducted into the recent trends of catalysts, novel reactions for organic syntheses, use of supercritical fluids, photocatalysts, biomimetic processes, etc. The development of substitutes for plastic additives was also studied. Since acceptance by the citizenry is quite important for green chemistry to take effect, educating and enlightening activities in the U.S., Britain, France, and Germany were inquired into. (NEDO)

  17. Primary water chemistry of VVERs-operating experience

    International Nuclear Information System (INIS)

    Kysela, Jan; Zmitko, Milan; Petrecky, Igor

    1998-01-01

    VVER units are operated in mixed boron-potassium-ammonia water chemistry. Several modifications of the water chemistry, differing in boron-potassium co-ordination and in the way how hydrogen concentration is produced and maintain in the coolant, is used. From the operational experience point of view VVER units do not show any significant problems connected with the primary coolant chemistry. The latest results indicate that dose rate levels are slowly returning to the former ones. An improvement of the radiation situation observed last two years is supported by the surface activity measurements. However, the final conclusion on the radiation situation can be made only after evaluation of the several following cycles. Further investigation is also needed to clarify a possible effect of modified water chemistry and shut-down chemistry on radioactivity build-up and dose rate level at Dukovany units. Structure materials composition has a significant effect on radiation situation in the units. It concerns mainly of cobalt content in SG material. There is no clear evidence of possible effect of the SG shut-down regimes on the radiation situation in the units even if the dose rate and surface activity data show wide spread for the individual reactor loops. (S.Y.)

  18. The JAERI and Universities joint project research reports on the 4th joint research project between JAERI and Universities on backend chemistry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-02-01

    In the Joint Research Project between JAERI and Universities on Backend Chemistry, the 4th-term researches of it were performed on sixteen themes from April of 1999 to March of 2001 under the four categories, i.e. Nuclear-chemistry and physical-chemistry properties of actinides', 'Solid state chemistry and nuclear fuel engineering of actinides', 'Solution chemistry and technologies for separation and analysis of actinides' and Treatment of radioactive waste and environmental chemistry'. The present report compiled the papers contributed to the Joint Research Project. (author)

  19. Non-thermally activated chemistry

    International Nuclear Information System (INIS)

    Stiller, W.

    1987-01-01

    The subject is covered under the following headings: state-of-the art of non-thermally activated chemical processes; basic phenomena in non-thermal chemistry including mechanochemistry, photochemistry, laser chemistry, electrochemistry, photo-electro chemistry, high-field chemistry, magneto chemistry, plasma chemistry, radiation chemistry, hot-atom chemistry, and positronium and muonium chemistry; elementary processes in non-thermal chemistry including nuclear chemistry, interactions of electromagnetic radiations, electrons and heavy particles with matter, ionic elementary processes, elementary processes with excited species, radicalic elementary processes, and energy-induced elementary processes on surfaces and interfaces; and comparative considerations. An appendix with historical data and a subject index is given. 44 figs., 41 tabs., and 544 refs

  20. Stability of hypersonic boundary-layer flows with chemistry

    Science.gov (United States)

    Reed, Helen L.; Stuckert, Gregory K.; Haynes, Timothy S.

    1993-01-01

    The effects of nonequilibrium chemistry and three dimensionality on the stability characteristics of hypersonic flows are discussed. In two-dimensional (2-D) and axisymmetric flows, the inclusion of chemistry causes a shift of the second mode of Mack to lower frequencies. This is found to be due to the increase in size of the region of relative supersonic flow because of the lower speeds of sound in the relatively cooler boundary layers. Although this shift in frequency is present in both the equilibrium and nonequilibrium air results, the equilibrium approximation predicts modes which are not observed in the nonequilibrium calculations (for the flight conditions considered). These modes are superpositions of incoming and outgoing unstable disturbances which travel supersonically relative to the boundary-layer edge velocity. Such solutions are possible because of the finite shock stand-off distance. Their corresponding wall-normal profiles exhibit an oscillatory behavior in the inviscid region between the boundary-layer edge and the bow shock. For the examination of three-dimensional (3-D) effects, a rotating cone is used as a model of a swept wing. An increase of stagnation temperature is found to be only slightly stabilizing. The correlation of transition location (N = 9) with parameters describing the crossflow profile is discussed. Transition location does not correlate with the traditional crossflow Reynolds number. A new parameter that appears to correlate for boundary-layer flow was found. A verification with experiments on a yawed cone is provided.

  1. γ-radiation effect on dicyclohexano-18-crown-6 aqueous solution in the presence of metal cations

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Chuhong; Peng, Jing; Li, Jiuqiang; Zhai, Maolina [Peking Univ. (China). Beijing National Laboratory for Molecular Sciences (BNLMS)

    2014-04-01

    γ-radiation effect on dicyclohexano-18-crown-6 (DCH18C6) aqueous solution in the presence of metal cations, such as K{sup +} and Sr{sup 2+}, was investigated, and some pale yellow precipitates were obtained at doses above 100 kGy. It was found that the complexation interaction of metal cations could accelerate the conversion of DCH18C6 into oligomers and the formation of precipitates, but it did not affect the formation mechanism of precipitates. Furthermore, the salting-out effect of metal cations played an important role in the precipitation. In order to inhibit the radiation-induced precipitation of DCH18C6 in water phase, nitric acid with a concentration of more than 1 M could be added to the system. The methods and results for analyzing radiation-induced products reported in this work are useful to understand the radiation chemistry behavior of DCH18C6 which is used as the extractant in the separation of long half-life radionuclides from spent nuclear fuel. (orig.)

  2. Chemistry in CESM-SE: Evaluation, Performance and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Lamarque, Jean-Francois [National Center for Atmospheric Research, Boulder, CO (United States); Conley, Andrew [National Center for Atmospheric Research, Boulder, CO (United States); Vitt, Francis [National Center for Atmospheric Research, Boulder, CO (United States); Drake, John [Univ. of Tennessee, Knoxville, TN (United States); Sun, Jian [Univ. of Tennessee, Knoxville, TN (United States)

    2016-01-06

    The purpose of the proposed work focused on development of chemistry representation within the Spectral Element (SE) dynamical core as implemented in the Community Earth System Model (CESM). More specifically, a main focus was on the ability of SE to accurately represent tracer transport. The proposed approach was to incrementally increase the complexity of the problem, starting from specified two-dimensional flow and tracers to simulations using specified dynamics and full chemistry. As demonstrated below, we have successfully studied all aspects of the proposed work, although only part of the work has been published in the refereed literature so far. Furthermore, because the SE dynamical core has been found to have several deficiencies that are still being investigated for solution, not all proposed tasks were finalized. In addition to the tests for SE performance, in an effort to decrease the computational burden of interactive chemistry, especially in the case of a large number of chemical species and chemical reactions, development on a faster chemical solver and implementation on GPUs has been implemented in CESM under the leadership of John Drake (U. Tennessee).

  3. Quantification of air plasma chemistry for surface disinfection

    International Nuclear Information System (INIS)

    Pavlovich, Matthew J; Clark, Douglas S; Graves, David B

    2014-01-01

    Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O 3 ) and nitrogen oxides (NO and NO 2 , or NO x ) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NO x mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications. (paper)

  4. Quantification of air plasma chemistry for surface disinfection

    Science.gov (United States)

    Pavlovich, Matthew J.; Clark, Douglas S.; Graves, David B.

    2014-12-01

    Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O3) and nitrogen oxides (NO and NO2, or NOx) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NOx mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications.

  5. Cross-Course Collaboration in the Undergraduate Chemistry Curriculum: Primary Kinetic Isotope Effect in the Hypochlorite Oxidation of 1-Phenylethanol in the Physical Chemistry Laboratory

    Science.gov (United States)

    Noll, Robert J.; Fitch, Richard W.; Kjonaas, Richard A.; Wyatt, Richard A.

    2017-01-01

    A kinetic isotope effect (KIE) experiment is described for the physical chemistry laboratory. Students conduct a hypochlorite (household bleach) oxidation of an equimolar mixture of 1-phenylethanol and 1-deuterio-1-phenylethanol to acetophenone. The reaction occurs in a biphasic reaction mixture and follows first-order kinetics with respect to…

  6. Effect of Virtual Analytical Chemistry Laboratory on Enhancing Student Research Skills and Practices

    Science.gov (United States)

    Bortnik, Boris; Stozhko, Natalia; Pervukhina, Irina; Tchernysheva, Albina; Belysheva, Galina

    2017-01-01

    This article aims to determine the effect of a virtual chemistry laboratory on university student achievement. The article describes a model of a laboratory course that includes a virtual component. This virtual component is viewed as a tool of student pre-lab autonomous learning. It presents electronic resources designed for a virtual laboratory…

  7. Advances in water chemistry control for BWRs and PWRs

    International Nuclear Information System (INIS)

    Wood, C.J.

    1997-01-01

    This paper is an overview of the effects of water chemistry developments on the current operation of nuclear power plants in the United States, and the mitigation of corrosion-related degradation processes and radiation field build-up processes through the use of advanced water chemistry. Recent modifications in water chemistry to control and reduce radiation fields are outlined, including revisions to the EPRI water chemistry guidelines for BWRs and PWR primary and secondary systems. The change from a single water chemistry specification for all plants to a set of options, from which a plant-specific chemistry programme can be defined, is described. (author)

  8. Green chemistry: A tool in Pharmaceutical Chemistry

    OpenAIRE

    Smita Talaviya; Falguni Majumdar

    2012-01-01

    Green chemistry expresses an area of research developing from scientific discoveries about pollution awareness and it utilizes a set of principles that reduces or eliminates the use or generation of hazardous substances in all steps of particular synthesis or process. Chemists and medicinal scientists can greatly reduce the risk to human health and the environment by following all the valuable principles of green chemistry. The most simple and direct way to apply green chemistry in pharmaceut...

  9. Optimum coolant chemistry in BWRs

    International Nuclear Information System (INIS)

    Lin, C.C.; Cowan, R.L.; Kiss, E.

    2004-01-01

    LWR water chemistry parameters are directly or indirectly related to the plant's operational performance and for a significant amount of Operation and Maintenance (O and M) costs. Obvious impacts are the operational costs associated with water treatment, monitoring and associated radwaste generation. Less obvious is the important role water chemistry plays in the magnitude of drywell shutdown dose rates, fuel corrosion performance and, (probably most importantly) materials degradation such as from stress corrosion cracking of piping and Reactor Pressure Vessel (RPV) internal components. To improve the operational excellence of the BWR and to minimize the impact of water chemistry on O and M costs. General Electric has developed the concept of Optimum Water Chemistry (OWC). The 'best practices' and latest technology findings from the U.S., Asia and Europe are integrated into the suggested OWC Specification. This concept, together with cost effective ways to meet the requirement, are discussed. (author)

  10. Stimulus Responsive Poly(ferrocenylsilanes): Redox Chemistry of Iron in the Main Chain

    NARCIS (Netherlands)

    Giannotti, M.I.; Lv, H.; Ma, Y.; Steenvoorden, M.P.; Overweg, A.R.; Roerdink, M.; Hempenius, Mark A.; Vancso, Gyula J.

    2006-01-01

    Redox chemistry of organometallic poly(ferrocenylsilane) polymers (soluble in organic or aqueous environment) is discussed. Poly(ferrocenyldimethylsilane) (PFDMS) was oxidized in CH2Cl2 solution with different oxidants. Oxidation was accomplished with stepwise increasing amounts of ferric chloride

  11. Variation of the Effectiveness of Hydrogen Water Chemistry in a Boiling Water Reactor during Startup Operations

    International Nuclear Information System (INIS)

    Yeh, Tsung-Kuang; Wang, Mei-Ya

    2012-09-01

    For mitigating intergranular stress corrosion cracking (IGSCC) in an operating boiling water reactor (BWR), the technology of hydrogen water chemistry (HWC) aiming at coolant chemistry improvement has been adopted worldwide. However, the hydrogen injection system employed in this technology was designed to operate only at power levels greater than 30% of the rated power or at coolant temperatures of greater than 450 deg. F. This system is usually in an idle and standby mode during a startup operation. The coolant in a BWR during a cold shutdown normally contains a relatively high level of dissolved oxygen from intrusion of atmospheric air. Accordingly, the structural materials in the primary coolant circuit (PCC) of a BWR could be exposed to a strongly oxidizing environment for a short period of time during a subsequent startup operation. At some plants, the feasibility of hydrogen water chemistry during startup operations has been studied, and its effectiveness on suppressing SCC initiation was evaluated. It is technically difficult to directly procure water chemistry data at various locations of an operating reactor. Accordingly, the impact of startup operation on water chemistry in the PCC of a BWR operating under normal water chemistry (NWC) or HWC can only be theoretically evaluated through computer modelling. In this study, a well-developed computer code DEMACE was used to investigate the variations in redox species concentration and in electrochemical corrosion potential (ECP) of components in the PCC of a domestic BWR during startup operations in the presence of HWC. Simulations were carried out for [H2] FW s ranging from 0.0 to 2.0 parts per million (ppm) and for power levels ranging from 2.5% to 11.3% during startup operations. Our analyses indicated that for power levels with steam generation in the core, a higher power level would tend to promote a more oxidizing coolant environment for the structural components and therefore lead to less HWC

  12. Bonding, structure and solid-state chemistry

    CERN Document Server

    Ladd, Mark

    2016-01-01

    This book is aimed at undergraduate students in both chemistry and those degree subjects in which chemistry forms a significant part. It does not reflect any particular academic year, and so finds a place during the normal span of degree studies in the physical sciences. An A-level standard in science and mathematics is presumed; additional mathematical treatments are discussed in Appendices. An introductory first chapter leads into the main subject matter, which is treated through four chapters in terms of the principle bonding forces of cohesion in the solid state; a further chapter discusses nanosize materials. Important applications of the study topics are interspersed at appropriate points within the text. Each chapter is provided with a set of problems of varying degrees of difficulty, so as to assist the reader in gaining a facility with the subject matter and its applications. The problems are supplemented by detailed tutorial solutions, some of which present additional relevant material that indicate...

  13. The Effects of Interactive Stratospheric Chemistry on Antarctic and Southern Ocean Climate Change in an AOGCM

    Science.gov (United States)

    Li, Feng; Newman, Paul; Pawson, Steven; Waugh, Darryn

    2014-01-01

    Stratospheric ozone depletion has played a dominant role in driving Antarctic climate change in the last decades. In order to capture the stratospheric ozone forcing, many coupled atmosphere-ocean general circulation models (AOGCMs) prescribe the Antarctic ozone hole using monthly and zonally averaged ozone field. However, the prescribed ozone hole has a high ozone bias and lacks zonal asymmetry. The impacts of these biases on model simulations, particularly on Southern Ocean and the Antarctic sea ice, are not well understood. The purpose of this study is to determine the effects of using interactive stratospheric chemistry instead of prescribed ozone on Antarctic and Southern Ocean climate change in an AOGCM. We compare two sets of ensemble simulations for the 1960-2010 period using different versions of the Goddard Earth Observing System 5 - AOGCM: one with interactive stratospheric chemistry, and the other with prescribed monthly and zonally averaged ozone and 6 other stratospheric radiative species calculated from the interactive chemistry simulations. Consistent with previous studies using prescribed sea surface temperatures and sea ice concentrations, the interactive chemistry runs simulate a deeper Antarctic ozone hole and consistently larger changes in surface pressure and winds than the prescribed ozone runs. The use of a coupled atmosphere-ocean model in this study enables us to determine the impact of these surface changes on Southern Ocean circulation and Antarctic sea ice. The larger surface wind trends in the interactive chemistry case lead to larger Southern Ocean circulation trends with stronger changes in northerly and westerly surface flow near the Antarctica continent and stronger upwelling near 60S. Using interactive chemistry also simulates a larger decrease of sea ice concentrations. Our results highlight the importance of using interactive chemistry in order to correctly capture the influences of stratospheric ozone depletion on climate

  14. Biocoordination chemistry. pH-metry titration method during study of biometal complexing with bioligands

    International Nuclear Information System (INIS)

    Dobrynina, N.A.

    1992-01-01

    Position of bioinorganic chemistry in the system of naturl science, as well as relations between bioinorganic and biocoordination chemistry, were considered. The content of chemical elements in geosphere and biosphere was analyzed. Characteristic features of biometal complexing with bioligands were pointed out. By way of example complex equilibria in solution were studie by the method of pH-metric titration using mathematical simulation. Advantages of the methods totality, when studying biosystems, were emphasized

  15. An ideal teaching program of nuclear chemistry in the undergraduate chemistry curriculum

    International Nuclear Information System (INIS)

    Uenak, T.

    2009-01-01

    It is well known that several reports on the common educational problems of nuclear chemistry have been prepared by certain groups of experts from time to time. According to very important statements in these reports, nuclear chemistry and related courses generally do not take sufficient importance in undergraduate chemistry curricula and it was generally proposed that nuclear chemistry and related courses should be introduced into undergraduate chemistry curricula at universities worldwide. Starting from these statements, an ideal program in an undergraduate chemistry curriculum was proposed to be introduced into the undergraduate chemistry program at the Department of Chemistry, Ege University, in Izmir, Turkey during the regular updating of the chemistry curriculum. Thus, it has been believed that this Department of Chemistry has recently gained an ideal teaching program in the field of nuclear chemistry and its applications in scientific, industrial, and medical sectors. In this contribution, the details of this program will be discussed. (author)

  16. Toxicity of TiO2 nanoparticles to Escherichia coli: effects of particle size, crystal phase and water chemistry.

    Directory of Open Access Journals (Sweden)

    Xiuchun Lin

    Full Text Available Controversial and inconsistent results on the eco-toxicity of TiO2 nanoparticles (NPs are commonly found in recorded studies and more experimental works are therefore warranted to elucidate the nanotoxicity and its underlying precise mechanisms. Toxicities of five types of TiO2 NPs with different particle sizes (10∼50 nm and crystal phases were investigated using Escherichia coli as a test organism. The effect of water chemistry on the nanotoxicity was also examined. The antibacterial effects of TiO2 NPs as revealed by dose-effect experiments decreased with increasing particle size and rutile content of the TiO2 NPs. More bacteria could survive at higher solution pH (5.0-10.0 and ionic strength (50-200 mg L(-1 NaCl as affected by the anatase TiO2 NPs. The TiO2 NPs with anatase crystal structure and smaller particle size produced higher content of intracellular reactive oxygen species and malondialdehyde, in line with their greater antibacterial effect. Transmission electron microscopic observations showed the concentration buildup of the anatase TiO2 NPs especially those with smaller particle sizes on the cell surfaces, leading to membrane damage and internalization. These research results will shed new light on the understanding of ecological effects of TiO2 NPs.

  17. Toxicity of TiO2 Nanoparticles to Escherichia coli: Effects of Particle Size, Crystal Phase and Water Chemistry

    Science.gov (United States)

    Lin, Xiuchun; Li, Jingyi; Ma, Si; Liu, Gesheng; Yang, Kun; Tong, Meiping; Lin, Daohui

    2014-01-01

    Controversial and inconsistent results on the eco-toxicity of TiO2 nanoparticles (NPs) are commonly found in recorded studies and more experimental works are therefore warranted to elucidate the nanotoxicity and its underlying precise mechanisms. Toxicities of five types of TiO2 NPs with different particle sizes (10∼50 nm) and crystal phases were investigated using Escherichia coli as a test organism. The effect of water chemistry on the nanotoxicity was also examined. The antibacterial effects of TiO2 NPs as revealed by dose-effect experiments decreased with increasing particle size and rutile content of the TiO2 NPs. More bacteria could survive at higher solution pH (5.0–10.0) and ionic strength (50–200 mg L−1 NaCl) as affected by the anatase TiO2 NPs. The TiO2 NPs with anatase crystal structure and smaller particle size produced higher content of intracellular reactive oxygen species and malondialdehyde, in line with their greater antibacterial effect. Transmission electron microscopic observations showed the concentration buildup of the anatase TiO2 NPs especially those with smaller particle sizes on the cell surfaces, leading to membrane damage and internalization. These research results will shed new light on the understanding of ecological effects of TiO2 NPs. PMID:25310452

  18. Effect of Formative Quizzes on Teacher Candidates’ Learning in General Chemistry

    OpenAIRE

    Yalaki, Yalcin; Bayram, Zeki

    2015-01-01

    Formative assessment or assessment for learning is one of the most emphasized educational innovations around the world. Two of the common strategies that could be used in formative assessment are use of summative tests for formative purposes and comment only marking. We utilized these strategies in the form of formative quizzes in a general chemistry course and measured its effect on students’ learning. The results of our weak-experimental design, which was conducted with 124 pre-service elem...

  19. Advances in BWR water chemistry

    International Nuclear Information System (INIS)

    Garcia, Susan E.; Giannelli, Joseph F.; Jarvis, Mary L.

    2012-09-01

    This paper reviews recent advances in Boiling Water Reactor (BWR) water chemistry control with examples of plant experiences at U.S. designed BWRs. Water chemistry advances provide some of the most effective methods for mitigating materials degradation, reducing fuel performance concerns and lowering radiation fields. Mitigation of stress corrosion cracking (SCC) of materials remains a high priority and improved techniques that have been demonstrated in BWRs will be reviewed, specifically hydrogen injection combined with noble metal chemical addition (NMCA) and the newer on-line noble metal application process (OLNC). Hydrogen injection performance, an important part of SCC mitigation, will also be reviewed for the BWR fleet, highlighting system improvements that have enabled earlier injection of hydrogen including the potential for hydrogen injection during plant startup. Water chemistry has been significantly improved by the application of pre-filtration and optimized use of ion exchange resins in the CP (condensate polishing) and reactor water cleanup (RWCU) systems. EPRI has monitored and supported water treatment improvements to meet water chemistry goals as outlined in the EPRI BWR Water Chemistry Guidelines, particularly those for SCC mitigation of reactor internals and piping, minimization of fuel risk due to corrosion and crud deposits and chemistry control for radiation field reduction. In recent years, a significant reduction has occurred in feedwater corrosion product input, particularly iron. A large percentage of plants are now reporting <0.1 ppb feedwater iron. The impacts to plant operation and chemistry of lower feedwater iron will be explored. Depleted zinc addition is widely practiced across the fleet and the enhanced focus on radiation reduction continues to emphasize the importance of controlling radiation source term. In addition, shutdown chemistry control is necessary to avoid excessive release of activated corrosion products from fuel

  20. Dynamic surface properties of poly(methylalkyldiallylammonium chloride) solutions

    Czech Academy of Sciences Publication Activity Database

    Novikova, A. A.; Vlasov, P. S.; Lin, S.-Y.; Sedláková, Zdeňka; Noskov, B. A.

    2017-01-01

    Roč. 80, November (2017), s. 122-127 ISSN 1876-1070 Institutional support: RVO:61389013 Keywords : polymer solutions * dynamic surface tension * dilational surface rheology Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 4.217, year: 2016

  1. An Introduction to the Fundamentals of Chemistry for the Marine Engineer - An Audio-Tutorial Correspondence Course (CH-1C).

    Science.gov (United States)

    Schlenker, Richard M.

    This document provides a study guide for a three-credit-hour fundamentals of chemistry course for marine engineer majors. The course is composed of 17 minicourses including: chemical reactions, atomic theory, solutions, corrosion, organic chemistry, water pollution, metric system, and remedial mathematics skills. Course grading, objectives,…

  2. Recent results from the chemistry of recoiling carbon and silicon atoms: The interplay between hot atom chemistry and gas kinetics

    International Nuclear Information System (INIS)

    Gaspar, P.P.; Garmestani, K.; Ferrieri, R.A.; Wolf, A.P.

    1990-01-01

    Recent results from the chemistry of recoiling carbon and silicon atoms illustrate the power of an experimental approach to the solution of complex mechanistic problems that combines the study of the reactions of recoiling atoms with conventional gas kinetic techniques. Included will be the reactions of 11 C atoms with anisole, addressing the question whether an aromatic pi-electron system can compete as a reactive site with carbon-hydrogen bonds

  3. Medicinal chemistry matters - a call for discipline in our discipline.

    Science.gov (United States)

    Johnstone, Craig

    2012-06-01

    Medicinal chemistry makes a vital contribution to small molecule drug discovery, and the quality of it contributes directly to research effectiveness as well as to downstream costs, speed and survival in development. In recent years, the discipline of medicinal chemistry has evolved and witnessed many noteworthy contributions that propose and offer potential improvements to medicinal chemistry practice; however, the impact of these ideas is limited by their acceptance and deployment into every-day activity and, as a result, the quality of medicinal chemistry remains variable. For the good of the industry and the medicinal chemistry discipline, there is a need to move from retrospective learning to prospective control of medicinal chemistry practice to improve cost effectiveness, probability of success and survival rates. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. BWR Water Chemistry Guidelines: 1993 Revision, Normal and hydrogen water chemistry

    International Nuclear Information System (INIS)

    Karlberg, G.; Goddard, C.; Fitzpatrick, S.

    1994-02-01

    The goal of water chemistry control is to extend the operating life of the reactor and rector coolant system, balance-of-plant components, and turbines while simultaneously controlling costs to safeguard the continued economic viability of the nuclear power generation investment. To further this goal an industry committee of chemistry personnel prepared guidelines to identify the benefits, risks, and costs associated with water chemistry in BWRs and to provide a template for an optimized water chemistry program. This document replaces the BWR Normal Water Chemistry Guidelines - 1986 Revision and the BWR Hydrogen Water Chemistry Guidelines -- 1987 Revision. It expands on the previous guidelines documents by covering the economic implications of BWR water chemistry control

  5. Prediction of protein loop geometries in solution

    NARCIS (Netherlands)

    Rapp, Chaya S.; Strauss, Temima; Nederveen, Aart; Fuentes, Gloria

    2007-01-01

    The ability to determine the structure of a protein in solution is a critical tool for structural biology, as proteins in their native state are found in aqueous environments. Using a physical chemistry based prediction protocol, we demonstrate the ability to reproduce protein loop geometries in

  6. Smart Cities Will Need Chemistry

    Directory of Open Access Journals (Sweden)

    Alexandru WOINAROSCHY

    2016-06-01

    Full Text Available A smart city is a sustainable and efficient urban centre that provides a high quality of life to its inhabitants through optimal management of its resources. Chemical industry has a key role to play in the sustainable evolution of the smart cities. Additionally, chemistry is at the heart of all modern industries, including electronics, information technology, biotechnology and nano-technology. Chemistry can make the smart cities project more sustainable, more energy efficient and more cost effective. There are six broad critical elements of any smart city: water management systems; infrastructure; transportation; energy; waste management and raw materials consumption. In all these elements chemistry and chemical engineering are deeply involved.

  7. Optimization of secondary side water chemistry in TQNPC

    International Nuclear Information System (INIS)

    Fang Lan

    2007-01-01

    This article briefly introduces the types of corrosion that may be happened on steam generator heat exchange tubes in Qinshan CANDU6 nuclear power station and chemical effects on corrosion. The water chemistry optimization on minimzing deposition and corrosion of steam generators are introduced. The article summarizes the experiences of plant chemistry control and morpholine operation, providing guidance for optimizing secondary side water chemistry in the future, giving reference on selection of secondary side alkali agent and setting water chemistry specifications for other nuclear power stations. (authors)

  8. Convection and chemistry effects in CVD: A 3-D analysis for silicon deposition

    Science.gov (United States)

    Gokoglu, S. A.; Kuczmarski, M. A.; Tsui, P.; Chait, A.

    1989-01-01

    The computational fluid dynamics code FLUENT has been adopted to simulate the entire rectangular-channel-like (3-D) geometry of an experimental CVD reactor designed for Si deposition. The code incorporated the effects of both homogeneous (gas phase) and heterogeneous (surface) chemistry with finite reaction rates of important species existing in silane dissociation. The experiments were designed to elucidate the effects of gravitationally-induced buoyancy-driven convection flows on the quality of the grown Si films. This goal is accomplished by contrasting the results obtained from a carrier gas mixture of H2/Ar with the ones obtained from the same molar mixture ratio of H2/He, without any accompanying change in the chemistry. Computationally, these cases are simulated in the terrestrial gravitational field and in the absence of gravity. The numerical results compare favorably with experiments. Powerful computational tools provide invaluable insights into the complex physicochemical phenomena taking place in CVD reactors. Such information is essential for the improved design and optimization of future CVD reactors.

  9. Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

    International Nuclear Information System (INIS)

    Ryan, R.R.

    1982-05-01

    This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research

  10. Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, R.R. (comp.)

    1982-05-01

    This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research.

  11. Controlling Chemistry in Dynamic Nanoscale Systems

    DEFF Research Database (Denmark)

    Jesorka, Aldo; Lizana, Ludvig; Konkoli, Zoran

    2011-01-01

    Spatial organization and shape dynamics are inherent properties of biological cells and cell interiors. There are strong indications that these features are important for the in vivo control of reaction parameters in biochemical transformations. Nanofluidic model devices founded on surfactant...... of the concept. Controlled release of chol-DNA molecules from SU-8 surfaces gives the possibility to dynamically change surface and/or solution properties in micro and nanoreactor applications, opening access to stable 2D chemistry on surface-based devices with potential for easy interfacing with conventional...

  12. Relationships among foliar chemistry, foliar polyamines, and soil chemistry in red spruce trees growing across the northeastern United States

    Science.gov (United States)

    Minocha, R.; Shortle, W.C.; Lawrence, G.B.; David, M.B.; Minocha, S.C.

    1997-01-01

    Forest trees are constantly exposed to various types of natural and anthropogenic stressors. A major long-term goal of our research is to develop a set of early physiological and biochemical markers of stress in trees before the appearance of visual symptoms. Six red spruce (Picea rubens Sarg.) stands from the northeastern United States were selected for collection of soil and foliage samples. All of the chosen sites had soil solution pH values below 4.0 in the Oa horizon but varied in their geochemistry. Some of these sites were apparently under some form of environmental stress as indicated by a large number of dead and dying red spruce trees. Samples of soil and needles (from apparently healthy red spruce trees) were collected from these sites four times during a two-year period. The needles were analyzed for perchloric acid-soluble polyamines and exchangeable inorganic ions. Soil and soil solution samples from the Oa and B horizons were analyzed for their exchange chemistry. The data showed a strong positive correlation between Ca and Mg concentrations in the needles and in the Oa horizon of the soil. However, needles from trees growing on relatively Ca-rich soils with a low exchangeable Al concentration and a low Al:Ca soil solution ratio had significantly lower concentrations of putrescine and spermidine than those growing on Ca-poor soils with a high exchangeable Al concentration and a high Al:Ca soil solution in the Oa horizon. The magnitude of this change was several fold higher for putrescine concentrations than for spermidine concentrations. Neither putrescine nor spermidine were correlated with soil solution Ca, Mg, and Al concentrations in the B horizon. The putrescine concentrations of the needles always correlated significantly with exchangeable Al (r2=0.73, p???0.05) and still solution Al:Ca ratios (r2=0.91, p???0.01) of the Oa horizon. This suggests that in conjunction with soil chemistry, putrescine and/or spermidine may be used as a potential

  13. Introduction to Computational Chemistry: Teaching Hu¨ckel Molecular Orbital Theory Using an Excel Workbook for Matrix Diagonalization

    Science.gov (United States)

    Litofsky, Joshua; Viswanathan, Rama

    2015-01-01

    Matrix diagonalization, the key technique at the heart of modern computational chemistry for the numerical solution of the Schrödinger equation, can be easily introduced in the physical chemistry curriculum in a pedagogical context using simple Hückel molecular orbital theory for p bonding in molecules. We present details and results of…

  14. Analysis of the Effect of Sequencing Lecture and Laboratory Instruction on Student Learning and Motivation Towards Learning Chemistry in an Organic Chemistry Lecture Course

    Science.gov (United States)

    Pakhira, Deblina

    2012-01-01

    Exposure to organic chemistry concepts in the laboratory can positively affect student performance, learning new chemistry concepts and building motivation towards learning chemistry in the lecture. In this study, quantitative methods were employed to assess differences in student performance, learning, and motivation in an organic chemistry…

  15. Selective solvation extraction of gold from alkaline cyanide solution by alkyl phosphorus esters

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.D.; Wan, R.Y.; Mooiman, M.B.; Sibrell, P.L.

    1987-01-01

    Research efforts have shown that solvation extraction of gold from alkaline cyanide solution is possible by alkyl phosphorus esters. Both tributyl phosphate (TBP) and dibutyl butyl phosphonate (DBBP) appear to be effective extractants for gold and exhibit high loading capacities exceeding 30 gpl. Selective solvation extraction of gold from alkaline cyanide solution can be achieved with selectivity factors relative to other cyanoanions as high as 1000 under certain circumstances. Variables influencing the selectivity such as ionic strength, temperature, and extractant structure, are discussed in terms of the extraction chemistry, which seems to involve the solvation of a M dot, dot, dot Au(CN)2 ion pair.

  16. Effects of low-level radioactive-waste disposal on water chemistry in the unsaturated zone at a site near Sheffield, Illinois, 1982-84

    Science.gov (United States)

    Peters, C.A.; Striegl, Robert G.; Mills, P.C.; Healy, R.W.

    1992-01-01

    A 1982-84 field study defined the chemistry of water collected from the unsaturated zone at a low-level radioactive-waste disposal site near Sheffield, Bureau County, Illinois. Chemical data were evaluated to determine the principal naturally occurring geochemical reactions in the unsaturated zone and to evaluate waste-induced effects on pore-water chemistry. Samples of precipitation, unsaturated-zone pore water, and saturated-zone water were analyzed for specific conductance, pH, alkalinity, major cations and anions, dissolved organic carbon, gross alpha and beta radiation, and tritium. Little change in concentration of most major constituents in the unsaturated-zone water was observed with respect to depth or distance from disposal trenches. Tritium and dissolved organic carbon concentrations were, however, dependent on proximity to trenches. The primary reactions, both on- site and off-site, were carbonate and clay dissolution, cation exchange, and the oxidation of pyrite. The major difference between on-site and off-site inorganic water chemistry resulted from the removal of the Roxana Silt and the Radnor Till Member of the Glasford Formation from on-site. Off-site, the Roxana Silt contributed substantial quantities of sodium to solution from montmorillonite dissolution and associated cation-exchange reactions. The Radnor Till Member provided exchange surfaces for magnesium. Precipitation at the site had an ionic composition of calcium zinc sulfate and an average pH of 4.6. Within 0.3 meter of the land surface, infiltrating rain water or snowmelt changed to an ionic canposition of calcium sulfate off-site and calcium bicarbonate on-site and had an average pH of 7.9; below that depth, pH averaged 7.5 and the ionic composition generally was calcium magnesium bicarbonate. Alkalinity and specific conductance differed primarily according to composition of geologic materials. Tritium concentrations ranged from 0.2 (detection limit) to 1,380 nanocuries per liter. The

  17. Scientific Information Analysis of Chemistry Dissertations Using Thesaurus of Chemistry

    Directory of Open Access Journals (Sweden)

    Taghi Rajabi

    2017-09-01

    Full Text Available : Concept maps of chemistry can be obtained from thesaurus of chemistry. Analysis of information in the field of chemistry is done at graduate level, based on comparing and analyzing chemistry dissertations by using these maps. Therefore, the use of thesaurus for analyzing scientific information is recommended. Major advantage of using this method, is that it is possible to obtain a detailed map of all academic researches across all branches of science. The researches analysis results in chemical science can play a key role in developing strategic research policies, educational programming, linking universities to industries and postgraduate educational programming. This paper will first introduce the concept maps of chemistry. Then, emerging patterns from the concept maps of chemistry will be used to analyze the trend in the academic dissertations in chemistry, using the data collected and stored in our database at Iranian Research Institute for Information Science and Technology (IranDoc over the past 10 years (1998-2009.

  18. Academic Achievement in Physics-Chemistry: The Predictive Effect of Attitudes and Reasoning Abilities

    Directory of Open Access Journals (Sweden)

    Paulo N. Vilia

    2017-06-01

    Full Text Available Science education plays a critical role as political priority due to its fundamental importance in engaging students to pursue technological careers considered essential in modern societies, in order to face scientific development challenges. High-level achievement on science education and positive attitudes toward science constitutes a crucial challenge for formal education. Several studies indicate close relationships between students’ attitudes, cognitive abilities, and academic achievement. The main purpose of this study is to analyze the impact of student’s attitudes toward the school discipline of Physics and Chemistry and their reasoning abilities on academic achievement on that school subject, among Portuguese 9th grade students using the data collected during the Project Academic Performance and Development: a longitudinal study on the effects of school transitions in Portuguese students (PTDC/CPE-CED/104884/2008. The participants were 470 students (267 girls – 56.8% and 203 boys – 43.2%, aged 14–16 years old (μ = 14.3 ± 0.58. The attitude data were collected using the Attitude toward Physics-Chemistry Questionnaire (ATPCQ and, the Reasoning Test Battery (RTB was used to assess the students reasoning abilities. Achievement was measured using the students’ quarterly (9-week grades in the physics and chemistry subject. The relationships between the attitude dimensions toward Physics-chemistry and the reasoning dimensions and achievement in each of the three school terms were assessed by multiple regression stepwise analyses and standardized regression coefficients (β, calculated with IBM SPSS Statistics 21 software. Both variables studied proved to be significant predictor variables of school achievement. The models obtained from the use of both variables were always stronger accounting for higher proportions of student’s grade variations. The results show that ATPCQ and RTB had a significantly positive relationship with

  19. Research Program to Investigate the Fundamental Chemistry of Technetium

    International Nuclear Information System (INIS)

    Edelstein, Norman M.; Burns, Carol J.; Shuh, David D.; Lukens, Wayne

    2000-01-01

    Technetium (99Tc, half-life = 2.13x105 years, b-emitter) is one of the radionuclides of major concern for nuclear waste disposal. This concern is due to the long half-life of 99Tc, the ease with which pertechnetate, TcO4 -, migrates in the geosphere, and the corresponding regulatory considerations. The problem of mobility of pertechnetate in the environment is compounded by the fact that pertechnetate is the thermodynamically stable form of technetium in aerobic environments. These two factors present challenges for the safe, long term immobilization of technetium in waste forms. Because of the stability of pertechnetate, technetium has been assumed to exist as pertechnetate in the aqueous phase of nuclear waste tanks. However, recent studies indicate that a significant fraction of the technetium is in a different chemical form. This program addresses the fundamental solution chemistry of technetium in the waste tank environment, and in a second part, the stability of technetium in various waste forms. The chemistry of this element will be studied in aqueous solutions at high pH, with various added salts such as nitrate, nitrite, and organic complexants, and as a function of radiation dose, to determine whether radiolysis effects can reduce TcO4 -. A separate facet of this research is the search for chemical forms of technetium that may be thermodynamically and/or kinetically stable and may be incorporated in various waste forms for long term storage. This phase of the program will address the problem of the possible oxidation of lower valent technetium species in various waste form matrices and the subsequent leaching of the highly soluble TcO4 -

  20. 13th AINSE radiation chemistry conference, 12-14 November 1986, Lucas Heights - AINSE Theatre

    International Nuclear Information System (INIS)

    1986-01-01

    Abstracts of papers are given which cover the fields of radiolysis in aqueous solutions, solids and gases, radiation polymerisation and degradation, excitation in solids and gases, and industrial applications of radiation chemistry

  1. Effects of solution P H on the adsorption of aromatic compounds from aqueous solutions by activated carbon

    International Nuclear Information System (INIS)

    Nouri, S.; Haghseresht, F.; Lu, M.

    2002-01-01

    Absorption of p-Cresol, Benzoic acid and Nitro Benzene by activated carbon from dilute aqueous solutions was carried out under controlled ph conditions at 310 k. In acidic conditions, well below the pK a of all solutes, it was observed that the adsorbate solubility and the electron density of its aromatic ring were the influencing factors on the extent of the adsorption by affecting the extent of London dispersion forces. In higher solution ph conditions, on the other hand, it was found that the electrostatic forces played a significant role on the extent of adsorption. The Effect of ph must be considered from its combined effects on the carbon surface and on the solute molecules. It was found that the uptake of the molecular forms of the aromatic solutes was dependent on the substituents of the aromatic ring. Adsorption of the solutes in higher P H values was found to be dependent on the concentration of anionic form of the solutes. All isotherms were fitted into Freundlich Isotherm Equations

  2. Chemistry of cost effective water treatment programme in HWP (Manuguru)

    International Nuclear Information System (INIS)

    Mohapatra, C.; Laxmana Prasad, K.

    2008-01-01

    In order to develop a water treatment programme following points must be kept in mind: Effectiveness to achieve desired water quality objectives; Compliance with regulatory requirements; Cost minimization; Safety; Easy operation and protection to equipments. Heavy Water Plant (Manuguru) laboratory has developed treatment programs to treat raw water and cooling water which satisfy the above requirements and has been in use for last several years successfully without any problem. These treatment programs have been given to other plants in Heavy Water Board for implementation. This paper describes the chemistry of the treatment program and cost minimization achieved. Further these treatments have helped the plant in achieving ΦZero Discharge and indirectly reduced the production cost. The chemistry parameters are monitored regularly to ascertain the effectiveness of these treatments. The areas where significant benefits derived are raw water treatment using polyelectrolyte instead of inorganic coagulant (alum), change over of regenerant of cation exchangers from hydrochloric acid to sulfuric acid and development of in-house cooling water treatment formulation. The advantages and cost effectiveness of these treatments are discussed in detail. Further these treatments helped the plant in achieving Zero discharge and indirectly reduced production cost of heavy water. The dosage of 3 ppm of polyelectrolyte can replace 90 ppm alum at turbidity level of 300 NTU of raw water which has resulted in cost saving of Rs. 15 - 20 Lakhs in a year besides other advantages. The changeover of regenerant from HCl to H 2 SO 4 will result in cost saving of at least Rs. 1.4 Crore a year along with other advantages. The change over of proprietary formulation to in-house formulation in cooling water treatment has resulted a saving about Rs. 11 Lakhs a year. To achieve the above objectives in a sustainable way the performance results are being monitored (author)

  3. Irradiation effects on electrical properties of DNA solution/Al Schottky diodes

    Science.gov (United States)

    Al-Ta'ii, Hassan Maktuff Jaber; Periasamy, Vengadesh; Iwamoto, Mitsumasa

    2018-04-01

    Deoxyribonucleic acid (DNA) has emerged as one of the most exciting organic material and as such extensively studied as a smart electronic material since the last few decades. DNA molecules have been reported to be utilized in the fabrication of small-scaled sensors and devices. In this current work, the effect of alpha radiation on the electrical properties of an Al/DNA/Al device using DNA solution was studied. It was observed that the carrier transport was governed by electrical interface properties at the Al-DNA interface. Current ( I)-voltage ( V) curves were analyzed by employing the interface limited Schottky current equations, i.e., conventional and Cheung and Cheung's models. Schottky parameters such as ideality factor, barrier height and series resistance were also determined. The extracted barrier height of the Schottky contact before and after radiation was calculated as 0.7845, 0.7877, 0.7948 and 0.7874 eV for the non-radiated, 12, 24 and 36 mGy, respectively. Series resistance of the structure was found to decline with the increase in the irradiation, which was due to the increase in the free radical root effects in charge carriers in the DNA solution. Results pertaining to the electronic profiles obtained in this work may provide a better understanding for the development of precise and rapid radiation sensors using DNA solution.

  4. A relativistic density functional study of uranyl hydrolysis and complexation by carboxylic acids in aqueous solution

    International Nuclear Information System (INIS)

    Ray, Rupashree Shyama

    2009-01-01

    In this work, the complexation of uranium in its most stable oxidation state VI in aqueous solution was studied computationally, within the framework of density functional (DF) theory. The thesis is divided into the following parts: Chapter 2 briefly summarizes the relevant general aspects of actinide chemistry and then focuses on actinide environmental chemistry. Experimental results on hydrolysis, actinide complexation by carboxylic acids, and humic substances are presented to establish a background for the subsequent discussion. Chapter 3 describes the computational method used in this work and the relevant features of the parallel quantum chemistry code PARAGAUSS employed. First, the most relevant basics of the applied density functional approach are presented focusing on relativistic effects. Then, the treatment of solvent effects, essential for an adequate modeling of actinide species in aqueous solution, will be introduced. At the end of this chapter, computational parameters and procedures will be summarized. Chapter 4 presents the computational results including a comparison to available experimental data. In the beginning, the mononuclear hydrolysis product of UO_2"2"+, [UO_2OH]"+, will be discussed. The second part deals with actinide complexation by carboxylate ligands. First of all the coordination number for uranylacetate will be discussed with respect to implications for the complexation of actinides by humic substances followed by the uranyl complexation of aromatic carboxylic acids in comparison to earlier results for aliphatic ones. In the end, the ternary uranyl-hydroxo-acetate are discussed, as models of uranyl humate complexation at ambient condition.

  5. Probing the Question Order Effect While Developing a Chemistry Concept Inventory

    Science.gov (United States)

    Undersander, Molly A.; Lund, Travis J.; Langdon, Laurie S.; Stains, Marilyne

    2017-01-01

    The design of assessment tools is critical to accurately evaluate students' understanding of chemistry. Although extensive research has been conducted on various aspects of assessment tool design, few studies in chemistry have focused on the impact of the order in which questions are presented to students on the measurement of students'…

  6. The difference between the metal ion extracted from the R.F. ion source by applying plasma chemistry reaction and by non-plasma range chemistry reaction

    International Nuclear Information System (INIS)

    Bai Gui Bin

    1987-01-01

    The paper introduced the difference between using plasma chemistry reaction draw metal ion and non-plasma range chemistry reaction in the R.F. ion source. By using of the plasma chemistry reaction draw metal ion higher percentage than non-plasma range chemistry reaction in the R.F. ion source. The authors plasma chemistry reaction to R.F. ion source and implanter successfully. The effect is very well, it has its own characteristic

  7. Progress report, Chemistry and Materials Division

    International Nuclear Information System (INIS)

    1982-02-01

    A marked asymmetry has been observed in the intensity of ions scattered from manganese atoms in a Mn-Al alloy as a function of incidence angle, under near-axial channeling conditions. Proton dechanneling has been used to discriminate between simple and cluster defects created by He-ion irradiation of an Al-Ag alloy crystal. An automated Langmuir surface has been constructed for study of the radiation chemistry of polyunsaturated compounds organized in molecular films. New information about reactions of nitric oxide (NO) has been obtained which suggests that the reaction of NO with O 2 in the gas phase is also an important reaction in the radiation chemistry of oxygenated nitrate and nitrite solutions. Development work on an ion-selective electrode for the determination of boron has been completed. Recent studies have resulted in improvements to the mass spectrometric determination of thorium, uranium and plutonium. Good agreement between the results of the determinations of atom percent fission by a stable isotope dilution Nd-148 and a uranium isotope ratio method was observed. Examination of a large number of iodine-induced crack initiation sites formed under conditions where the hydrides are in solution has shown no evidence for the involvement of any second phase particles, or any local segregation of impurities or alloying elements. Reproducible improvement in the purity of zirconium has been achieved by the electrotransport method. Doppler broadening studies of positron annihilation in electron irradiated Zr and Ti have been completed

  8. Exploring Dominant Types of Explanations Built by General Chemistry Students

    Science.gov (United States)

    Talanquer, Vicente

    2010-01-01

    The central goal of our study was to explore the nature of the explanations generated by science and engineering majors with basic training in chemistry to account for the colligative properties of solutions. The work was motivated by our broader interest in the characterisation of the dominant types of explanations that science college students…

  9. Climate and chemistry effects of a regional scale nuclear conflict

    Science.gov (United States)

    Stenke, A.; Hoyle, C. R.; Luo, B.; Rozanov, E.; Gröbner, J.; Maag, L.; Brönnimann, S.; Peter, T.

    2013-10-01

    Previous studies have highlighted the severity of detrimental effects for life on earth after an assumed regionally limited nuclear war. These effects are caused by climatic, chemical and radiative changes persisting for up to one decade. However, so far only a very limited number of climate model simulations have been performed, giving rise to the question how realistic previous computations have been. This study uses the coupled chemistry climate model (CCM) SOCOL, which belongs to a different family of CCMs than previously used, to investigate the consequences of such a hypothetical nuclear conflict. In accordance with previous studies, the present work assumes a scenario of a nuclear conflict between India and Pakistan, each applying 50 warheads with an individual blasting power of 15 kt ("Hiroshima size") against the major population centers, resulting in the emission of tiny soot particles, which are generated in the firestorms expected in the aftermath of the detonations. Substantial uncertainties related to the calculation of likely soot emissions, particularly concerning assumptions of target fuel loading and targeting of weapons, have been addressed by simulating several scenarios, with soot emissions ranging from 1 to 12 Tg. Their high absorptivity with respect to solar radiation leads to a rapid self-lofting of the soot particles into the strato- and mesosphere within a few days after emission, where they remain for several years. Consequently, the model suggests earth's surface temperatures to drop by several degrees Celsius due to the shielding of solar irradiance by the soot, indicating a major global cooling. In addition, there is a substantial reduction of precipitation lasting 5 to 10 yr after the conflict, depending on the magnitude of the initial soot release. Extreme cold spells associated with an increase in sea ice formation are found during Northern Hemisphere winter, which expose the continental land masses of North America and Eurasia to a

  10. Climate and chemistry effects of a regional scale nuclear conflict

    Directory of Open Access Journals (Sweden)

    A. Stenke

    2013-10-01

    Full Text Available Previous studies have highlighted the severity of detrimental effects for life on earth after an assumed regionally limited nuclear war. These effects are caused by climatic, chemical and radiative changes persisting for up to one decade. However, so far only a very limited number of climate model simulations have been performed, giving rise to the question how realistic previous computations have been. This study uses the coupled chemistry climate model (CCM SOCOL, which belongs to a different family of CCMs than previously used, to investigate the consequences of such a hypothetical nuclear conflict. In accordance with previous studies, the present work assumes a scenario of a nuclear conflict between India and Pakistan, each applying 50 warheads with an individual blasting power of 15 kt ("Hiroshima size" against the major population centers, resulting in the emission of tiny soot particles, which are generated in the firestorms expected in the aftermath of the detonations. Substantial uncertainties related to the calculation of likely soot emissions, particularly concerning assumptions of target fuel loading and targeting of weapons, have been addressed by simulating several scenarios, with soot emissions ranging from 1 to 12 Tg. Their high absorptivity with respect to solar radiation leads to a rapid self-lofting of the soot particles into the strato- and mesosphere within a few days after emission, where they remain for several years. Consequently, the model suggests earth's surface temperatures to drop by several degrees Celsius due to the shielding of solar irradiance by the soot, indicating a major global cooling. In addition, there is a substantial reduction of precipitation lasting 5 to 10 yr after the conflict, depending on the magnitude of the initial soot release. Extreme cold spells associated with an increase in sea ice formation are found during Northern Hemisphere winter, which expose the continental land masses of North

  11. Self-assembly in casting solutions of block copolymer membranes

    KAUST Repository

    Marques, Debora S.; Vainio, Ulla; Moreno Chaparro, Nicolas; Calo, Victor M.; Bezahd, Ali Reza; Pitera, Jed W.; Peinemann, Klaus; Nunes, Suzana Pereira

    2013-01-01

    Membranes with exceptional pore regularity and high porosity were obtained from block copolymer solutions. We demonstrate by small-angle X-ray scattering that the order which gives rise to the pore morphology is already incipient in the casting solution. Hexagonal order was confirmed in PS-b-P4VP 175k-b-65k solutions in DMF/THF/dioxane with concentrations as high as 24 wt%, while lamellar structures were obtained in more concentrated solutions in DMF or DMF/dioxane. The change in order has been understood with the support of dissipative particle dynamic modeling. © 2013 The Royal Society of Chemistry.

  12. Review of information on the radiation chemistry of materials around waste canisters in salt and assessment of the need for additional experimental information

    Energy Technology Data Exchange (ETDEWEB)

    Jenks, G.H.; Baes, C.F. Jr.

    1980-03-01

    The brines, vapors, and salts precipitated from the brines will be exposed to gamma rays and to elevated temperatures in the regions close to a waste package in the salt. Accordingly, they will be subject to changes in composition brought about by reactions induced by the radiations and heat. This report reviews the status of information on the radiation chemistry of brines, gases, and solids which might be present around a waste package in salt and to assess the need for additional laboratory investigations on the radiation chemistry of these materials. The basic aspects of the radiation chemistry of water and aqueous solutions, including concentrated salt solutions, were reviewed briefly and found to be substantially unchanged from those presented in Jenks's 1972 review of radiolysis and hydrolysis in salt-mine brines. Some additional information pertaining to the radiolytic yields and reactions in brine solutions has become available since the previous review, and this information will be useful in the eventual, complete elucidation of the radiation chemistry of the salt-mine brines. 53 references.

  13. The present status of iodine chemistry research in Canada and its application to reactor safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, K R [Ontario Hydro Nuclear, Toronto (Canada); Kupferschmid, W C.H.; Wren, J C; Ball, J M [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

    1996-12-01

    The current need to understand iodine chemistry in a reactor safety context has become more sharply focussed as the level of that understanding has advanced. At the same time, the situations of most concern within containment, from an iodine perspective, are also being redefined in the light of that understanding. The present paper summarises these developments. Over the past five years, considerable advances have occurred in our understanding of iodine chemistry under conditions of interest in reactor accidents. A number of key experiments have yielded important results in the areas of solution chemistry, the role of surfaces, the importance of organics and the effects of impurities. This understanding supplements the already substantial gains made in characterising the key roles of pH and the effects of radiation. All these factors underline the now evident fact that the kinetics of iodine are the controlling factor when radiation is involved, and that a number of reactive species, not present in thermal reactions, effectively control the observed volatility of iodine. In this paper, recent advances are summarised and the present status of our understanding of iodine chemistry is reviewed. Specifically, an attempt is made to identify those areas where our understanding appears to be relatively complete, and to flag the remaining critical areas where our attention is currently focussed. The state of our modelling capability is reviewed, as is the significance or related areas such as the role of mass transfer. Finally, an overview is presented of the significance of this work for reactor safety, and our expectations for its application over the near term future. (author) 2 figs., 12 refs.

  14. The present status of iodine chemistry research in Canada and its application to reactor safety analysis

    International Nuclear Information System (INIS)

    Weaver, K.R.; Kupferschmid, W.C.H.; Wren, J.C.; Ball, J.M.

    1996-01-01

    The current need to understand iodine chemistry in a reactor safety context has become more sharply focussed as the level of that understanding has advanced. At the same time, the situations of most concern within containment, from an iodine perspective, are also being redefined in the light of that understanding. The present paper summarises these developments. Over the past five years, considerable advances have occurred in our understanding of iodine chemistry under conditions of interest in reactor accidents. A number of key experiments have yielded important results in the areas of solution chemistry, the role of surfaces, the importance of organics and the effects of impurities. This understanding supplements the already substantial gains made in characterising the key roles of pH and the effects of radiation. All these factors underline the now evident fact that the kinetics of iodine are the controlling factor when radiation is involved, and that a number of reactive species, not present in thermal reactions, effectively control the observed volatility of iodine. In this paper, recent advances are summarised and the present status of our understanding of iodine chemistry is reviewed. Specifically, an attempt is made to identify those areas where our understanding appears to be relatively complete, and to flag the remaining critical areas where our attention is currently focussed. The state of our modelling capability is reviewed, as is the significance or related areas such as the role of mass transfer. Finally, an overview is presented of the significance of this work for reactor safety, and our expectations for its application over the near term future. (author) 2 figs., 12 refs

  15. Analysis of Copper-Bearing Rocks and Minerals for Their Metal Content Using Visible Spectroscopy: A First Year Chemistry Laboratory Exploration

    Science.gov (United States)

    Bopegedera, A. M. R. P.

    2016-01-01

    General chemistry and introductory chemistry students were presented with a laboratory exploration for the determination of the mass percent of copper in rock and mineral samples. They worked independently in the laboratory, which involved multiple lab (pipetting, preparing standard solutions by quantitative dilution, recording visible spectra…

  16. Exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology.

    Science.gov (United States)

    Ojima, Iwao

    2013-07-05

    Over the last three decades, my engagement in "fluorine chemistry" has evolved substantially because of the multidisciplinary nature of the research programs. I began my research career as a synthetic chemist in organometallic chemistry and homogeneous catalysis directed toward organic synthesis. Then, I was brought into a very unique world of "fluorine chemistry" in the end of 1970s. I started exploring the interface of fluorine chemistry and transition metal homogeneous catalysis first, which was followed by amino acids, peptides, and peptidomimetics for medicinal chemistry. Since then, I have been exploring the interfaces of fluorine chemistry and multidisciplinary fields of research involving medicinal chemistry, chemical biology, cancer biology, and molecular imaging. This perspective intends to cover my fruitful endeavor in the exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology in a chronological order to show the evolution of my research interest and strategy.

  17. Szilard-Chalmers Effect in Permanganate Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Broda, E.

    1944-07-01

    This report was written by E. Broda at the Cavendish Laboratory (Cambridge) in January 1944 by Engelbert Broda and is about the Szilard-Chalmers effect in Permanganate Solutions. The Szilard-Chalmers effect in permanganate was studied in order to see what extent it is quantitative, or at least reproducible, in different conditions. The measurement description and results are discussed in this report. (nowak)

  18. New design architecture decisions on water chemistry support systems at new VVER plants

    International Nuclear Information System (INIS)

    Kumanina, V.E.; Yurmanova, A.V.

    2010-01-01

    Major goals of nuclear power plant design upgrading are reduction of cost and construction time with unconditional safety assurance. Main ways of further improvement of nuclear power plant design are as follows: review of the results of research engineering and development and of new technologies; harmonization with international codes and standards; justified liberalization of conservatism based on operating experience and use of improved design codes. Operational experience of Russian and foreign NPPs has shown that the designs of new NPPs could be improved by upgrading water chemistry support systems. Some new design solutions for water chemistry support systems are currently implemented at new WWER plants such as Bushehr, Kudankulam, Belene, Balakovo Units 5 and 6, AES-2006 project. The paper highlights the improvements of the following systems and processes: low temperature high pressure primary coolant clean-up system; primary system surface preconditioning during pre-start hot functional testing; steam generator blowdown cleanup system; secondary water chemistry; phosphate water chemistry in intermediate cooling circuits and other auxiliary systems; alternator cooling system water chemistry; steam generator cleanup and decontamination systems. (author)

  19. Corrosion under stress of AISI 304 steel in thiocyanate solutions

    International Nuclear Information System (INIS)

    Perillo, P.M.; Duffo, G.S.

    1989-01-01

    Corrosion susceptibility under stress of AISI 304 steel sensitized in a sodium thiocyanate solution has been studied and results were compared with those obtained with solutions of thiosulfate and tetrathionate. Sensitized steel type 304 is highly susceptible to corrosion when under intergranular stress (IGSCC) in thiocyanate solutions but the aggressiveness of this anion is less than that of the other sulphur anions studied (thiosulfate and tetrathionate). This work has been partly carried out in the Chemistry Department. (Author) [es

  20. An Investigation of the Effects of Reader Characteristics on Reading Comprehension Of a General Chemistry Text

    Science.gov (United States)

    Neiles, Kelly Y.

    There is great concern in the scientific community that students in the United States, when compared with other countries, are falling behind in their scientific achievement. Increasing students' reading comprehension of scientific text may be one of the components involved in students' science achievement. To investigate students' reading comprehension this quantitative study examined the effects of different reader characteristics, namely, students' logical reasoning ability, factual chemistry knowledge, working memory capacity, and schema of the chemistry concepts, on reading comprehension of a chemistry text. Students' reading comprehension was measured through their ability to encode the text, access the meanings of words (lexical access), make bridging and elaborative inferences, and integrate the text with their existing schemas to make a lasting mental representation of the text (situational model). Students completed a series of tasks that measured the reader characteristic and reading comprehension variables. Some of the variables were measured using new technologies and software to investigate different cognitive processes. These technologies and software included eye tracking to investigate students' lexical accessing and a Pathfinder program to investigate students' schema of the chemistry concepts. The results from this study were analyzed using canonical correlation and regression analysis. The canonical correlation analysis allows for the ten variables described previously to be included in one multivariate analysis. Results indicate that the relationship between the reader characteristic variables and the reading comprehension variables is significant. The resulting canonical function accounts for a greater amount of variance in students' responses then any individual variable. Regression analysis was used to further investigate which reader characteristic variables accounted for the differences in students' responses for each reading comprehension

  1. A comparative study of the effect of α-, β-, and γ-cyclodextrins as stabilizing agents in the synthesis of silver nanoparticles using a green chemistry method

    Energy Technology Data Exchange (ETDEWEB)

    Suárez-Cerda, Javier [Centro de Graduados e Investigación, Instituto Tecnológico de Tijuana, Apartado Postal 1166, Tijuana, B. C. (Mexico); Nuñez, Gabriel Alonso [Centro de Nanociencia y Nanotecnología de la UNAM, CNyN, Km. 107 Carretera Tijuana-Ensenada, C.P. 22860 Ensenada, B. C. (Mexico); Espinoza-Gómez, Heriberto [Facultad de Ciencias Químicas e Ingeniería, UABC, Calzada Universidad 14418 Parque Industrial Internacional, C.P. 22390 Tijuana, B.C. (Mexico); Flores-López, Lucía Z., E-mail: lzflores@hotmail.com [Centro de Graduados e Investigación, Instituto Tecnológico de Tijuana, Apartado Postal 1166, Tijuana, B. C. (Mexico)

    2014-10-01

    This paper describes the effect of different types of cyclodextrins (CDs) in the synthesis of silver nanoparticles (Ag-NPs), using an easy green chemistry method. The Ag-NPs were obtained using an aqueous silver nitrate solution (AgNO{sub 3}) with α-, β-, or γ-CDs (aqueous solutions) as stabilizing agents, employing the chemical reduction method with citric acid as a reducing agent. A comparative study was done to determine which cyclodextrin (CD) was the best stabilizing agent, and we found out that β-CD was the best due to the number of glucopyranose units in its structure. The formation of the Ag-NPs was demonstrated by analysis of UV–vis spectroscopy, atomic force microscopy (AFM), scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS) and transmission electron microscopy (TEM). SEM–EDS showed the formation of a cluster with a significant amount of silver, for β-CD-Ag-NPs, spherical agglomerates can be observed. However, for α-, γ-CD, the agglomerates do not have a specific form, but their appearance is porous. TEM analysis shows spherical nanoparticles in shape and size between ∼ 0.5 to 7 nm. The clear lattice fringes in TEM images and the typical selected area electron diffraction (SAED) pattern, showed that the Ag-NPs obtained were highly crystalline with a face cubic center structure (FCC). - Highlights: • We report a green chemistry method for silver nanoparticles (Ag-NPs) synthesis. • We study the effect of cyclodextrin type on the silver nanoparticles (Ag-NPs) synthesis. • The silver nanoparticles (Ag-NPs) characterization were done by UV–vis, AFM, SEM–EDS, and TEM. • The Ag-NPs obtained have a face cubic center structure (FCC). • The nanoparticles obtained are spherical in shape and between ∼ 0.5 and 7 nm in size.

  2. A comparative study of the effect of α-, β-, and γ-cyclodextrins as stabilizing agents in the synthesis of silver nanoparticles using a green chemistry method

    International Nuclear Information System (INIS)

    Suárez-Cerda, Javier; Nuñez, Gabriel Alonso; Espinoza-Gómez, Heriberto; Flores-López, Lucía Z.

    2014-01-01

    This paper describes the effect of different types of cyclodextrins (CDs) in the synthesis of silver nanoparticles (Ag-NPs), using an easy green chemistry method. The Ag-NPs were obtained using an aqueous silver nitrate solution (AgNO 3 ) with α-, β-, or γ-CDs (aqueous solutions) as stabilizing agents, employing the chemical reduction method with citric acid as a reducing agent. A comparative study was done to determine which cyclodextrin (CD) was the best stabilizing agent, and we found out that β-CD was the best due to the number of glucopyranose units in its structure. The formation of the Ag-NPs was demonstrated by analysis of UV–vis spectroscopy, atomic force microscopy (AFM), scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS) and transmission electron microscopy (TEM). SEM–EDS showed the formation of a cluster with a significant amount of silver, for β-CD-Ag-NPs, spherical agglomerates can be observed. However, for α-, γ-CD, the agglomerates do not have a specific form, but their appearance is porous. TEM analysis shows spherical nanoparticles in shape and size between ∼ 0.5 to 7 nm. The clear lattice fringes in TEM images and the typical selected area electron diffraction (SAED) pattern, showed that the Ag-NPs obtained were highly crystalline with a face cubic center structure (FCC). - Highlights: • We report a green chemistry method for silver nanoparticles (Ag-NPs) synthesis. • We study the effect of cyclodextrin type on the silver nanoparticles (Ag-NPs) synthesis. • The silver nanoparticles (Ag-NPs) characterization were done by UV–vis, AFM, SEM–EDS, and TEM. • The Ag-NPs obtained have a face cubic center structure (FCC). • The nanoparticles obtained are spherical in shape and between ∼ 0.5 and 7 nm in size

  3. Recent studies of uranium and plutonium chemistry in alkaline radioactive waste solutions

    International Nuclear Information System (INIS)

    King, William D.; Wilmarth, William R.; Hobbs, David T.; Edwards, Thomas B.

    2008-01-01

    Solubility studies of uranium and plutonium in a caustic, radioactive Savannah River Site tank waste solution revealed the existence of uranium supersaturation in the as-received sample. Comparison of the results to predictions generated from previously published models for solubility in these waste types revealed that the U model poorly predicts solubility while Pu model predictions are quite consistent with experimental observations. Separate studies using simulated Savannah River Site evaporator feed solution revealed that the known formation of sodium aluminosilicate solids in waste evaporators can promote rapid precipitation of uranium from supersaturated solutions

  4. PWR water chemistry controls: a perspective on industry initiatives and trends relative to operating experience and the EPRI PWR water chemistry guidelines

    International Nuclear Information System (INIS)

    Fruzzetti, K.; Choi, S.; Haas, C.; Pender, M.; Perkins, D.

    2010-01-01

    An effective PWR water chemistry control program must address the following goals: Minimize materials degradation (e.g., PWSCC, corrosion of fuel, corrosion damage of steam generator (SG) tubes); Maintain fuel integrity and good performance; Minimize corrosion product transport (e.g., transport and deposition on the fuel, transport into the SGs where it can foul tube surfaces and create crevice environments for the concentration of corrosive impurities); Minimize dose rates. Water chemistry control must be optimized to provide overall improvement considering the sometimes variant constraints of the goals listed above. New technologies are developed for continued mitigation of materials degradation, continued fuel integrity and good performance, continued reduction of corrosion product transport, and continued minimization of plant dose rates. The EPRI chemistry program, in coordination with other EPRI programs, strives to improve these areas through application of chemistry initiatives, focusing on these goals. This paper highlights the major initiatives and issues with respect to PWR primary and secondary system chemistry and outlines the recent, on-going, and proposed work to effectively address them. These initiatives are presented in light of recent operating experience, as derived from EPRI's PWR chemistry monitoring and assessment program, and EPRI's water chemistry guidelines. (author)

  5. Analytical Chemistry as Methodology in Modern Pure and Applied Chemistry

    OpenAIRE

    Honjo, Takaharu

    2001-01-01

    Analytical chemistry is an indispensable methodology in pure and applied chemistry, which is often compared to a foundation stone of architecture. In the home page of jsac, it is said that analytical chemistry is a learning of basic science, which treats the development of method in order to get usefull chemical information of materials by means of detection, separation, and characterization. Analytical chemistry has recently developed into analytical sciences, which treats not only analysis ...

  6. Effect of Solution pH on the Adsorption of Paracetamol on Chemically Modified Activated Carbons

    Directory of Open Access Journals (Sweden)

    Valentina Bernal

    2017-06-01

    Full Text Available Paracetamol adsorption in acidic, neutral and basic media on three activated carbons with different chemistry surfaces was studied. A granular activated carbon (GAC was prepared from coconut shell; starting from this sample, an oxidized activated carbon (GACo was obtained by treating the GAC with a boiling solution of 6 M nitric acid, so to generate a greater number of oxygenated surface groups. In addition, a reduced activated carbon (GACr was obtained by heating the GAC at 1173 K, to remove the oxygenated surface groups. Paracetamol adsorption was higher for GACr due to the lower presence of oxygenated surface functional groups. Moreover, adsorption was highest at neutral pH. The magnitude of the interactions between paracetamol molecules and activated carbons was studied by measuring the immersion enthalpies of activated carbons in solution of paracetamol at different concentrations and pH values and by calculating the interaction enthalpy. The highest value was obtained for GACr in a paracetamol solution of 1000 mg L−1 at pH 7, confirming that paracetamol adsorption is favoured on basic activated carbons at pH values near to neutrality. Finally, the Gibbs energy changes confirmed the latter result, allowing explaining the different magnitudes of the interactions between paracetamol and activated carbons, as a function of solution pH.

  7. Fundamentals of nuclear chemistry

    International Nuclear Information System (INIS)

    Majer, K.

    1982-01-01

    The textbook is a Czech-to-German translation of the second revised edition and covers the subject under the headings: general nuclear chemistry, methods of nuclear chemistry, preparative nuclear chemistry, analytical nuclear chemistry, and applied chemistry. The book is especially directed to students

  8. Surface chemistry essentials

    CERN Document Server

    Birdi, K S

    2013-01-01

    Surface chemistry plays an important role in everyday life, as the basis for many phenomena as well as technological applications. Common examples range from soap bubbles, foam, and raindrops to cosmetics, paint, adhesives, and pharmaceuticals. Additional areas that rely on surface chemistry include modern nanotechnology, medical diagnostics, and drug delivery. There is extensive literature on this subject, but most chemistry books only devote one or two chapters to it. Surface Chemistry Essentials fills a need for a reference that brings together the fundamental aspects of surface chemistry w

  9. Radiation chemistry in development and research of radiation biology

    International Nuclear Information System (INIS)

    Min Rui

    2010-01-01

    During the establishment and development of radiation biology, radiation chemistry acts like bridge which units the spatial and temporal insight coming from radiation physics with radiation biology. The theory, model, and methodology of radiation chemistry play an important role in promoting research and development of radiation biology. Following research development of radiation biology effects towards systems radiation biology the illustration and exploration both diversity of biological responses and complex process of biological effect occurring remain to need the theory, model, and methodology come from radiation chemistry. (authors)

  10. Evaluation of neutralization treatment processes and their use for uranium tailings solutions

    International Nuclear Information System (INIS)

    Sherwood, D.R.; Opitz, B.E.; Serne, R.J.

    1985-01-01

    The potential for groundwater contamination from the typically acidic mill wastes that are disposed of in tailings impoundments is of primary concern at uranium mill sites in the US. Solution-treatment processes provide a system for limiting the environmental impact from acidic seepage. Treatment of uranium tailings solutions from evaporation ponds, underdrains, and surface seeps could aid in decommissioning active sites or be used as an emergency measure to avert possible uncontrolled discharges. At present, neutralization processes appear to be best suited for treating uranium mill tailings solution because they can, at a reasonable cost, limit the solution concentration of many contaminants and thus reduce the potential for groundwater contamination. However, the effectiveness of the neutralization process depends on the reagent used as well as the chemistry of the waste stream. This article provides a description of neutralization processes, an assessment of their performance on acidic uranium tailings leachates, and recommendations for their use at US uranium mill sites

  11. An overview of KANUPP operating experience in chemistry

    International Nuclear Information System (INIS)

    Hashmi, T.

    2010-01-01

    KANUPP is a small CANDU® type PHWR (137MWe), commissioned in 1972 and now operating after life extension (PLEX) since 2004. This paper contains an overview of the plant operating experience in chemistry control over the past year including life extension period. Emphasis is on: Success story; Practices; Future improvements in chemistry programs. Considerable efforts are underway to maintain plant equipment and systems to mitigate the effect of plant ageing. The improvements that have been made at the station are as under: Heat transport system (HTS) chemistry, its effects on construction material; Feed water chemistry on secondary side (considering the condenser leaks). Strict chemistry control is being exercised for the heat transport system (HTS) for its better chemistry control. For short term, the changes are limited to pH adjustments of HTS. This change decreases the rate of thinning of outlet feeders as noted in some CANDUs® due to flow accelerated corrosion (FAC). Water Treatment Plant has been refurbished to get very low total dissolved solids (TDS) de-mineralized water for secondary side systems of the plant. Experience of steam generators flushing before startup, sludge pile analyses mapping, verification of pH from different sampling points of SGs, are the short term mitigating actions to address sludge pile problem in steam generators (SGs). The R and D on HTS and SGs is multifaceted and is aimed at achieving optimum chemistry control. Study is being conducted for improving chemistry control for the material, equipment and systems of the plant. (author)

  12. Effect of electrochemical treatments on the surface chemistry of activated carbon

    OpenAIRE

    Berenguer Betrián, Raúl; Marco Lozar, Juan Pablo; Quijada Tomás, César; Cazorla Amorós, Diego; Morallón Núñez, Emilia

    2008-01-01

    The effect of the electrochemical treatment (galvanostatic electrolysis in a filter-press electrochemical cell) on the surface chemistry and porous structure of a granular activated carbon (GAC) has been analyzed by means of temperature-programmed desorption and N2 (at 77 K) and CO2 (at 273 K) adsorption isotherms. The anodic and cathodic treatments, the applied current (between 0.2 and 2.0 A) and the type of electrolyte (NaOH, H2SO4 and NaCl)have been studied as electrochemical variables. Bo...

  13. Modeling the atmospheric chemistry of TICs

    Science.gov (United States)

    Henley, Michael V.; Burns, Douglas S.; Chynwat, Veeradej; Moore, William; Plitz, Angela; Rottmann, Shawn; Hearn, John

    2009-05-01

    An atmospheric chemistry model that describes the behavior and disposition of environmentally hazardous compounds discharged into the atmosphere was coupled with the transport and diffusion model, SCIPUFF. The atmospheric chemistry model was developed by reducing a detailed atmospheric chemistry mechanism to a simple empirical effective degradation rate term (keff) that is a function of important meteorological parameters such as solar flux, temperature, and cloud cover. Empirically derived keff functions that describe the degradation of target toxic industrial chemicals (TICs) were derived by statistically analyzing data generated from the detailed chemistry mechanism run over a wide range of (typical) atmospheric conditions. To assess and identify areas to improve the developed atmospheric chemistry model, sensitivity and uncertainty analyses were performed to (1) quantify the sensitivity of the model output (TIC concentrations) with respect to changes in the input parameters and (2) improve, where necessary, the quality of the input data based on sensitivity results. The model predictions were evaluated against experimental data. Chamber data were used to remove the complexities of dispersion in the atmosphere.

  14. Solving vertical transport and chemistry in air pollution models

    International Nuclear Information System (INIS)

    Berkvens, P.J.F.; Botchev, M.A.; Verwer, J.G.; Krol, M.C.; Peters, W.

    2000-01-01

    For the time integration of stiff transport-chemistry problems from air pollution modelling, standard ODE solvers are not feasible due to the large number of species and the 3D nature. The popular alternative, standard operator splitting, introduces artificial transients for short-lived species. This complicates the chemistry solution, easily causing large errors for such species. In the framework of an operational global air pollution model, we focus on the problem formed by chemistry and vertical transport, which is based on diffusion, cloud-related vertical winds, and wet deposition. Its specific nature leads to full Jacobian matrices, ruling out standard implicit integration. We compare Strang operator splitting with two alternatives: source splitting and an (unsplit) Rosenbrock method with approximate matrix factorization, all having equal computational cost. The comparison is performed with real data. All methods are applied with half-hour time steps, and give good accuracies. Rosenbrock is the most accurate, and source splitting is more accurate than Strang splitting. Splitting errors concentrate in short-lived species sensitive to solar radiation and species with strong emissions and depositions. 30 refs

  15. Quantum chemistry simulation on quantum computers: theories and experiments.

    Science.gov (United States)

    Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

    2012-07-14

    It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.

  16. Chemistry of Technetium

    International Nuclear Information System (INIS)

    Omori, Takashi

    2001-01-01

    Since the late 1970's the coordination chemistry of technetium has been developed remarkably. The background of the development is obviously related to the use of technetium radiopharmaceuticals for diagnosis in nuclear medicine. Much attention has also been denoted to the chemical behavior of environmental 99 Tc released from reprocessing plants. This review covers the several aspects of technetium chemistry, including production of radioisotopes, analytical chemistry and coordination chemistry. In the analytical chemistry, separation of technetium, emphasizing chromatography and solvent extraction, is described together with spectrophotometric determination of technetium. In the coordination chemistry of technetium, a characteristic feature of the chemistry of Tc(V) complexes is referred from the view point of the formation of a wide variety of highly stable complexes containing the Tc=O or Tc≡N bond. Kinetic studies of the preparation of Tc(III) complexes using hexakis (thiourea) technetium(III) ion as a starting material are summarized, together with the base hydrolysis reactions of Tc(III), Tc(IV) and Tc(V) complexes. (author)

  17. Effects of D-region RF heating studied with the Sodankylä Ion Chemistry model

    Directory of Open Access Journals (Sweden)

    C.-F. Enell

    2005-07-01

    Full Text Available The upper mesosphere and lower thermosphere, or ionospheric D region, is an atmospheric layer which is difficult to access experimentally. A useful method that also has a large potential for further studies is artificial heating of electrons by means of powerful radio transmitters. Here we estimate the effect of D-region heating for a few typical cases of high electron density – daylight, typical auroral electron precipitation, and a solar proton event – by coupling a model of RF electron heating to the Sodankylä Ion Chemistry (SIC model. The predicted effects are among others an increase in the ratio of the concentration of negative ions to that of free electrons, and an increase in the absorption of cosmic noise as measured by riometers. For the model runs presented in this paper we have calculated the absorption for the frequency (38.2MHz of the IRIS imaging riometer in Kilpisjärvi, Finland, as observing the ionosphere above the EISCAT Heater in Tromsø, Norway. The predicted enhancements of the absorption are 0.2–0.8dB, an effect which is clearly detectable.

    Keywords. Ionosphere (Active experiments; Ion chemistry and composition; Wave propagation

  18. Effects of D-region RF heating studied with the Sodankylä Ion Chemistry model

    Directory of Open Access Journals (Sweden)

    C.-F. Enell

    2005-07-01

    Full Text Available The upper mesosphere and lower thermosphere, or ionospheric D region, is an atmospheric layer which is difficult to access experimentally. A useful method that also has a large potential for further studies is artificial heating of electrons by means of powerful radio transmitters. Here we estimate the effect of D-region heating for a few typical cases of high electron density – daylight, typical auroral electron precipitation, and a solar proton event – by coupling a model of RF electron heating to the Sodankylä Ion Chemistry (SIC model. The predicted effects are among others an increase in the ratio of the concentration of negative ions to that of free electrons, and an increase in the absorption of cosmic noise as measured by riometers. For the model runs presented in this paper we have calculated the absorption for the frequency (38.2MHz of the IRIS imaging riometer in Kilpisjärvi, Finland, as observing the ionosphere above the EISCAT Heater in Tromsø, Norway. The predicted enhancements of the absorption are 0.2–0.8dB, an effect which is clearly detectable. Keywords. Ionosphere (Active experiments; Ion chemistry and composition; Wave propagation

  19. Uranium (VI) chemistry at the interface solution/minerals (quartz and aluminium hydroxide): experiments and spectroscopic investigations of the uranyl surface species

    International Nuclear Information System (INIS)

    Froideval, A.

    2004-09-01

    This study deals with the understanding of the uranyl chemistry at the 0.1 M NaNO 3 solution/mineral (quartz and aluminium hydroxide) interface. The aims are:(i) to identify and to characterize the different uranyl surface species (mononuclear, polynuclear complexes and/or precipitates...), i.e. the coordination environments of sorbed/precipitated uranyl ions, by using X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) and time-resolved laser-induced fluorescence spectroscopy (TRLFS), and;(ii) to investigate the influence of pH, initial uranyl aqueous concentration and hydroxyl ligand concentration on the uranyl surface speciation. Our study on the speciation of uranyl ions at the quartz surface (i) confirms the formation of uranyl polynuclear/oligomers on quartz from moderate (1 μmol/m 2 ) to high (26 μmol/m 2 ) uranyl surface concentrations and (ii) show that theses polynuclear species coexist with uranyl mononuclear surface species over a pH range ≅ 5-8.5 and a wide range of initial uranyl concentration o f the solutions (10-100 μM). The uranyl concentration of these surface species depends on pH and on the initial uranyl aqueous concentration. Hydrate (surface-) precipitates and/or adsorbed polynuclear species and monomeric uranyl surface complexes are formed on aluminium hydroxide. Uranyl mononuclear complexes are predominant at acidic pH, as well as uranyl in solution or on the surface. Besides mononuclear species, precipitates and/or adsorbed polynuclear species are predominantly formed at neutral pH values on aluminium hydroxide. A main contribution of our investigations is that precipitation and/or adsorption of polynuclear species seem to occur at low uranyl surface concentrations (0.01-0.4 μmol/m 2 ). The uranyl surface speciation is mainly dependent on the pH and the aluminol ligand concentration. (author)

  20. Enhanced Tumor Retention Effect by Click Chemistry for Improved Cancer Immunochemotherapy.

    Science.gov (United States)

    Mei, Ling; Liu, Yayuan; Rao, Jingdong; Tang, Xian; Li, Man; Zhang, Zhirong; He, Qin

    2018-05-30

    Because of the limited drug concentration in tumor tissues and inappropriate treatment strategies, tumor recurrence and metastasis are critical challenges for effectively treating malignancies. A key challenge for effective delivery of nanoparticles is to reduce uptake by reticuloendothelial system and to enhance the permeability and retention effect. Herein, we demonstrated Cu(I)-catalyzed click chemistry triggered the aggregation of azide/alkyne-modified micelles, enhancing micelles accumulation in tumor tissues. In addition, combined doxorubicin with the adjuvant monophosphoryl lipid A, an agonist of toll-like receptor4, generated immunogenic cell death, which further promoted maturity of dendritic cells, antigen presentation and induced strong effector T cells in vivo. Following combined with anti-PD-L1 therapy, substantial antitumor and metastasis inhibitory effects were achieved because of the reduced PD-L1 expression and regulatory T cells. In addition, effective long-term immunity from memory T cell responses protected mice from tumor recurrence.

  1. Primary processes in radiation chemistry. LET (Linear Energy Transfer) effect in water radiolysis

    International Nuclear Information System (INIS)

    Trupin-Wasselin, V.

    2000-01-01

    The effect of ionizing radiations on aqueous solutions leads to water ionization and then to the formation of radical species and molecular products (e - aq , H . , OH . , H 2 O 2 , H 2 ). It has been shown that the stopping power, characterized by the LET value (Linear Energy Transfer) becomes different when the nature of the ionizing radiations is different. Few data are nowadays available for high LET radiations such as protons and high energy heavy ions. These particles have been used to better understand the primary processes in radiation chemistry. The yield of a chemical dosimeter (the Fricke dosimeter) and those of the hydrogen peroxide have been determined for different LET. The effect of the dose rate on the Fricke dosimeter yield and on the H 2 O 2 yield has been studied too. When the dose rate increases, an increase of the molecular products yield is observed. At very high dose rate, this yield decreases on account of the attack of the molecular products by radicals. The H 2 O 2 yield in alkaline medium decreases when the pH reaches 12. This decrease can be explained by a slowing down of the H 2 O 2 formation velocity in alkaline medium. Superoxide radical has also been studied in this work. A new detection method: the time-resolved chemiluminescence has been perfected for this radical. This technique is more sensitive than the absorption spectroscopy. Experiments with heavy ions have allowed to determine the O 2 .- yield directly in the irradiation cell. The experimental results have been compared with those obtained with a Monte Carlo simulation code. (O.M.)

  2. Adsorption of benzene and toluene from aqueous solutions onto activated carbon and its acid and heat treated forms: influence of surface chemistry on adsorption.

    Science.gov (United States)

    Wibowo, N; Setyadhi, L; Wibowo, D; Setiawan, J; Ismadji, S

    2007-07-19

    The influence of surface chemistry and solution pH on the adsorption of benzene and toluene on activated carbon and its acid and heat treated forms were studied. A commercial coal-based activated carbon F-400 was chosen as carbon parent. The carbon samples were obtained by modification of F-400 by means of chemical treatment with HNO3 and thermal treatment under nitrogen flow. The treatment with nitric acid caused the introduction of a significant number of oxygenated acidic surface groups onto the carbon surface, while the heat treatment increases the basicity of carbon. The pore characteristics were not significantly changed after these modifications. The dispersive interactions are the most important factor in this adsorption process. Activated carbon with low oxygenated acidic surface groups (F-400Tox) has the best adsorption capacity.

  3. Effects of water chemistry and fluid dynamics on wall thinning behavior. Part 1. Development of FAC model focused on water chemistry and composition of material

    International Nuclear Information System (INIS)

    Fujiwara, Kazutoshi; Domae, Masafumi; Ohta, Joji; Yoneda, Kimitoshi; Inada, Fumio

    2009-01-01

    Flow Accelerated Corrosion (FAC), which is one of the important subjects at fossil and nuclear power plans, is caused by the accelerated dissolution of protective oxide film due to the turbulent flow. The influence factors on FAC such as water chemistry, material, and fluid dynamics are closely related to the oxide property so that the risk of FAC can be reduced by the suitable control of water chemistry. There are some FAC models and evaluation codes of FAC rate. Some of them are used in wall thinning management of nuclear power plant in some country. Nevertheless, these FAC codes include many empirical parameters so that some uncertainty to evaluate the synergistic effectiveness of factors are the controversial point for the application of FAC code to wall thinning management in Japanese nuclear power plant. In this study, a FAC model that can evaluate the effect of temperature, NH3 concentration, chromium content, and dissolved oxygen concentration on FAC rate was developed by considering the diffusion of dissolved species. The critical dissolved oxygen concentration, which can inhibit FAC, was also calculated by this model. (author)

  4. Crevice corrosion of biomedical alloys: a novel method of assessing the effects of bone cement and its chemistry.

    Science.gov (United States)

    Bryant, Michael; Hu, Xinming; Farrar, Richard; Brummitt, Ken; Freeman, Robert; Neville, Anne

    2013-07-01

    In this study, five commercially available poly(methyl methacrylate) PMMA bone cements were tested to investigate the effects of antibiotics on the severity of crevice corrosion. Bone cements with varying chemistry were also tested. A test method was developed in part reference to ASTM F746-04. Cylindrical specimens were fitted with a bone cement tapered collar, creating consistent crevice conditions. Crevice corrosion was then studied using potentiodynamic polarization techniques in 0.9% NaCl solution (pH7.4) at 37°C. Surface analyses using a light microscope and scanning electron microscopy were also conducted to investigate the surface morphology after accelerated electrochemical testing. Initial testing of commercially available bone cements indicated that different PMMA bone cements can affect the initiation and propagation mechanism of crevice corrosion. Further studies, utilising electrochemical and mass spectroscopy techniques, have identified that the addition of radiopaque agent and antibiotics affect the initiation mechanisms of 316L stainless steel, whilst significantly increasing the extent of propagation in CoCrMo alloys. Copyright © 2013 Wiley Periodicals, Inc.

  5. The effect of online quizzes on student achievement in high school chemistry

    Science.gov (United States)

    Deeter, Christopher L.

    The idea of student engagement has come to the forefront of the United States educational system over the past decade. Student engagement requires learners to be actively involved in all stages of the learning process. This study focuses on the use of online quizzes in the chemistry classroom as a means to help students become more engaged in their learning outside of the classroom. Students were given three different types of online quizzes over the course of a chemistry chapter. Student scores on end of the chapter examinations was used to determine whether there was a significant difference in the amount of learning that occurred when a student took each of the three types of online quizzes. Students in a private parochial high school chemistry class completed online quizzes over the course of a semester. The quizzes were taken after completing assigned readings from the chemistry text. After each reading, a third of the students took online multiple-choice quizzes, a third took a paragraph quiz, and a third took no quiz. Scores received from end of chapter tests were evaluated to determine if the impact each of the quiz types had on the learning. All statistical analysis was done using SPSS using two-way split plot ANOVA with condition (paragraph, multiple-choice, nothing) as the within subject factor and group (A, B, C) as between subject factor. The data indicates that there was no significance within the condition F (1.877, 90.087) =.996, p>.05, or the interaction results. F (3.754, 90.087) =.509, p>.05. The data indicated that the effect of group was not significant either. F (2, 48) =.981, p>.05. Interviews undertaken to explain this outcome discovered that students did not become engaged with the content until the night before each test. When they did so, they used a teacher-provided study guide as their primary learning tool.

  6. Physical Chemistry '98: Fourth International Conference on Fundamental and Applied Aspects of Physical Chemistry - Papers

    International Nuclear Information System (INIS)

    Ribnikar, S.; Anic, S.

    1998-01-01

    The proceedings has following chapters: Plenary lectures; Chemical Thermodynamics; Spectroscopy, Molecular Structures, Physical Chemistry of Plasma; Kinetics, Catalysis, Nonlinear Dynamics; Electrochemistry; Biophysical Chemistry, Photochemistry, Radiation Chemistry; Radiochemistry, Nuclear Chemistry; Solid State Physical Chemistry, Material Science; Macromolecular Physical Chemistry; Environmental Protection; Phase Boundaries; Complex Compounds; General Physical Chemistry. A separated abstract was prepared for each of the 20 papers selected from the three chapters: Biophysical Chemistry, Photochemistry, Radiation Chemistry; Radiochemistry, Nuclear Chemistry. and Environmental Protection. Refs and figs

  7. Predicted effect of power uprating on the water chemistry of commercial boiling water reactors

    International Nuclear Information System (INIS)

    Yeh, Tsung-Kuang; Wang, Mei-Ya; Chu, Charles F.; Chang Ching

    2009-01-01

    The approach of power uprating has been adopted by operators of light water reactors in the past few decades in order to increase the power generation efficiency of nuclear reactors. The power uprate strategy is apparently applicable to the three nuclear reactors in Taiwan as well. When choosing among the three types of power uprating, measurement uncertainty, stretch power uprating, and extended power uprating, a deliberate and thorough evaluation is required before a final decision and an optimal selection can be made. One practical way of increasing the reactor power is to deliberately adjust the fuel loading pattern and the control rod pattern and thus to avoid replacing the primary coolant pump with a new one of larger capacity. The power density of the reactor will increase with increasing power, but the mass flow rate in the primary coolant circuit (PCC) of a light water reactor will slightly increase (usually by less than 5 %) or even remain unchanged. Accordingly, an uprated power would induce higher neutron and gamma photon dose rates in the reactor coolant but have a minor or no effect on the mass flow rate of the primary coolant. The radiolysis product concentrations and the electrochemical corrosion potential (ECP) values differ largely in the PCC of a boiling water reactor (BWR). It is very difficult to measure the water chemistry data directly at various locations of an actual reactor. Thus the impact of power uprating on the water chemistry of a BWR operating under hydrogen water chemistry (HWC) can only be theoretically evaluated through computer modelling. In this study, the DEMACE computer code was modified to investigate the impact of power uprating on the water chemistry under a fixed mass flow rate in the primary coolant circuit of a BWR/6 type plant. Simulations were carried out for hydrogen concentrations in feedwater ranging from 0.0 to 2.0 mg . kg -1 and for power levels ranging from 100 % to 120 %. The responses of water chemistry and ECP

  8. Rheological study of chitosan acetate solutions containing chitin nanofibrils

    Czech Academy of Sciences Publication Activity Database

    Mikešová, Jana; Hašek, Jindřich; Tishchenko, Galina; Morganti, P.

    2014-01-01

    Roč. 112, 4 November (2014), s. 753-757 ISSN 0144-8617 EU Projects: European Commission(XE) 315233 - N-CHITOPACK Institutional support: RVO:61389013 Keywords : rheology * chitosan solutions * chitin nanofibrils Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.074, year: 2014

  9. Learning chemistry from text: The effect of decision making

    Science.gov (United States)

    Pedersen, Jon; J., Ronald; Alice, Bonnstetter; Corkill, J.; Glover, John A.

    Two experiments examined the relative effects of questions requiring decisions, statements providing the decision information to students, questions not requiring decisions, and control procedures on students' memory for chemistry text reading materials. Experiment 1 employed immediate recall. The results of Experiment 1 indicated that students who made and justified decisions about the contents recalled significantly more information than students in any other condition. In addition, students who answered questions that did not require decisions recalled significantly more of the content than students in the control or the statements conditions. No other contrasts reached significance. Experiment 2 employed delayed recall assessed one week after reading. The results confirmed those of Experiment 1. The overall results of the study are discussed in terms of an elaboration perspective on memory.

  10. New travelling wave solutions for nonlinear stochastic evolution

    Indian Academy of Sciences (India)

    The nonlinear stochastic evolution equations have a wide range of applications in physics, chemistry, biology, economics and finance from various points of view. In this paper, the (′/)-expansion method is implemented for obtaining new travelling wave solutions of the nonlinear (2 + 1)-dimensional stochastic ...

  11. Environmental chemistry. Seventh edition

    Energy Technology Data Exchange (ETDEWEB)

    Manahan, S.E. [Univ. of Missouri, Columbia, MO (United States)

    1999-11-01

    This book presents a basic understanding of environmental chemistry and its applications. In addition to providing updated materials in this field, the book emphasizes the major concepts essential to the practice of environmental chemistry. Topics of discussion include the following: toxicological chemistry; toxicological chemistry of chemical substances; chemical analysis of water and wastewater; chemical analysis of wastes and solids; air and gas analysis; chemical analysis of biological materials and xenobiotics; fundamentals of chemistry; and fundamentals of organic chemistry.

  12. Amine chemistry. Update on impact on resin

    International Nuclear Information System (INIS)

    Bachman, Gregory; Kellogg, Douglas; Wilkes, Marty

    2012-01-01

    Impurity removal in the steam cycle and the associated prevention of corrosion and/or fouling of system components are the goals of ion exchange resins. However, in many instances (such as a switch to amine chemistry or a change in product specifications), resins do not remove, and, in fact, contribute impurities to the steam cycle. This paper reviews recent data compiled to determine the direct and indirect effects of amines on ion exchange resins used in the power industry. Water chemistries have improved in recent years, in large part due to changes in chemistry and resins, but it is necessary to continue to develop products, processes and techniques to reduce impurities and improve overall water chemistry in power plant systems. (orig.)

  13. Amine chemistry. Update on impact on resin

    Energy Technology Data Exchange (ETDEWEB)

    Bachman, Gregory; Kellogg, Douglas [Siemens Industry, Inc., Rockford, IL (United States). Technology and Lab Services; Wilkes, Marty [Siemens Industry, Inc., Rockford, IL (United States). Water Technologies Div.

    2012-03-15

    Impurity removal in the steam cycle and the associated prevention of corrosion and/or fouling of system components are the goals of ion exchange resins. However, in many instances (such as a switch to amine chemistry or a change in product specifications), resins do not remove, and, in fact, contribute impurities to the steam cycle. This paper reviews recent data compiled to determine the direct and indirect effects of amines on ion exchange resins used in the power industry. Water chemistries have improved in recent years, in large part due to changes in chemistry and resins, but it is necessary to continue to develop products, processes and techniques to reduce impurities and improve overall water chemistry in power plant systems. (orig.)

  14. Degradation of Highly Alloyed Metal Halide Perovskite Precursor Inks: Mechanism and Storage Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Benjia [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wheeler, Lance M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Christians, Jeffrey A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Moore, David [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Harvey, Steven P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Berry, Joseph J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Van Hest, Marinus F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Barnes, Frank S. [University of Colorado; Shaheen, Sean E. [University of Colorado

    2018-03-02

    Whereas the promise of metal halide perovskite (MHP) photovoltaics (PV) is that they can combine high efficiency with solution-processability, the chemistry occurring in precursor inks is largely unexplored. Herein, we investigate the degradation of MHP solutions based on the most widely used solvents, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). For the MHP inks studied, which contain formamidinium (FA+), methylammonium (MA+), cesium (Cs+), lead (Pb2+), bromide (Br-), and iodide (I-), dramatic compositional changes are observed following storage of the inks in nitrogen in the dark. We show that hydrolysis of DMF in the precursor solution forms dimethylammonium formate, which subsequently incorporates into the MHP film to compromise the ability of Cs+ and MA+ to stabilize FA+-based MHP. The changes in solution chemistry lead to a modification of the perovskite film stoichiometry, band gap, and structure. The solid precursor salts are stable when ball-milled into a powder, allowing for the storage of large quantities of stoichiometric precursor materials.

  15. Final Report, Research Program to Investigate the Fundamental Chemistry of Technetium

    International Nuclear Information System (INIS)

    Lukens, Wayne W. Jr.; Fickes, Michael J.; Bucher, Jerome J.; Burns, Carol J.; Edelstein, Norman M.; Shuh, David K.

    2000-01-01

    The purpose is to increase the basic scientific understanding of technetium chemistry to better understand the behavior of technetium in chemical environments relevant to DOE. Two important areas in need of study are the behavior of technetium in highly alkaline solutions similar to high-level nuclear waste, and its behavior in different waste forms. This research program addressed these two needs. Two separate approaches were used in this program. The first focus was to understand the basic solution chemistry of technetium, which underlies its behavior in the highly alkaline environment of the nuclear waste tanks located at the Savannah River and Hanford Sites. The specific problems at these sites are related to the anomalous oxidation state of technetium (Schroeder 1995). Although, at high pH, technetium should exist in its highest oxidation state as TcO 4 - , soluble, lower-valent technetium species have been observed in certain wastes. The specific unknowns that this program sought to answer are the nature of lower valent technetium species that can be formed in highly alkaline solution and whether pertechnetate undergoes radiolytic reduction in highly alkaline solution when nitrate is present in excess. The second focus area is the behavior of technetium immobilized in various waste forms. The behavior of technetium in cement wastes was examined to gain information about its long-term stability. Specifically, this research examined the oxidation of reduced technetium species by components present in high-level waste that are incorporated into cement waste along with technetium

  16. Antiparallel Dynamic Covalent Chemistries.

    Science.gov (United States)

    Matysiak, Bartosz M; Nowak, Piotr; Cvrtila, Ivica; Pappas, Charalampos G; Liu, Bin; Komáromy, Dávid; Otto, Sijbren

    2017-05-17

    The ability to design reaction networks with high, but addressable complexity is a necessary prerequisite to make advanced functional chemical systems. Dynamic combinatorial chemistry has proven to be a useful tool in achieving complexity, however with some limitations in controlling it. Herein we introduce the concept of antiparallel chemistries, in which the same functional group can be channeled into one of two reversible chemistries depending on a controllable parameter. Such systems allow both for achieving complexity, by combinatorial chemistry, and addressing it, by switching from one chemistry to another by controlling an external parameter. In our design the two antiparallel chemistries are thiol-disulfide exchange and thio-Michael addition, sharing the thiol as the common building block. By means of oxidation and reduction the system can be reversibly switched from predominantly thio-Michael chemistry to predominantly disulfide chemistry, as well as to any intermediate state. Both chemistries operate in water, at room temperature, and at mildly basic pH, which makes them a suitable platform for further development of systems chemistry.

  17. Effect of Water Chemistry Factors on Flow Accelerated Corrosion : pH, DO, Hydrazine

    International Nuclear Information System (INIS)

    Lee, Eun Hee; Kim, Kyung Mo; Kim, Hong Pyo

    2013-01-01

    Flow accelerated corrosion(FAC) of the carbon steel piping in pressurized water reactors(PWRs) has been major issue in nuclear industry. Severe accident at Surry Unit 2 in 1986 initiated the worldwide interest in this area. Major parameters influencing FAC are material composition, microstructure, water chemistry, and hydrodynamics. Qualitative behaviors of FAC have been well understood but quantitative data about FAC have not been published for proprietary reason. In order to minimize the FAC in PWRs, the optimal method is to control water chemistry factors. Chemistry factors influencing FAC such as pH, corrosion potential, and hydrazine contents were reviewed in this paper. FAC rate decreased with pH up to 10 because magnetite solubility decreased with pH. Corrosion potential is generally controlled dissolved oxygen (DO) and hydrazine in secondary water. DO increased corrosion potential. FAC rate decreased with DO by stabilizing magnetite at low DO concentration or by formation of hematite at high DO concentration. Even though hydrazine is generally used to remove DO, hydrazine itself thermally decomposed to ammonia, nitrogen, and hydrogen raising pH. Hydrazine could react with iron and increased FAC rate. Effect of hydrazine on FAC is rather complex and should be careful in FAC analysis. FAC could be managed by adequate combination of pH, corrosion potential, and hydrazine

  18. The chemistry of the liquid alkali metals

    International Nuclear Information System (INIS)

    Addison, C.C.

    1984-01-01

    A study of liquid alkali metals. It encourages comparison with molecular solvents in chapter covering the nature and reactivity of dissolved species, solvation, solubility and electrical conductivity of solutions. It demonstrates lab techniques unique to liquid alkali metals. It discusses large-scale applications from storage batteries to sodium-cooled reactors and future fusion reactors, and associated technological problems. Contents: Some Basic Physical and Chemical Properties; Manipulation of the Liquids; The Chemistry of Purification Methods; Species Formed by Dissolved Elements; Solubilities and Analytical Methods; Alkali Metal Mixtures; Solvation in Liquid Metal; Reactions Between Liquid Alkali Metals and Water; Reactions of Nitrogen with Lithium and the Group II Metals in Liquid Sodium; The Formation, Dissociation and Stability of Heteronuclear Polyatomic Anions; Reactions of the Liquid Alkali Metals and Their Alloys with Simple Alipatic Hydrocarbons; Reactions of the Liquid Alkali Metals with Some Halogen Compounds; Hydrogen, Oxygen and Carbon Meters; Surface Chemistry and Wetting; Corrosion of Transition Metals by the Liquid Alkali Metals; Modern Applications of the Liquid Alkali Metals

  19. More Chemistry with Light! More Light in Chemistry!

    Science.gov (United States)

    Bach, Thorsten

    2015-09-21

    "…︁ Why is chemistry overlooked when talking about light? Is the photon a physical particle per se? Are all important light-induced processes biological? Maybe the role of light for chemistry and the role of chemistry for light may be far less important than a few eccentric scientists would like to believe. From the perspective of a synthetically oriented photochemist, however, the facts are different …︁" Read more in the Editorial by Thorsten Bach. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Implications, large and small, from chemical education research for the teaching of chemistry

    Directory of Open Access Journals (Sweden)

    Peter J. Fensham

    2002-05-01

    Full Text Available Research studies in chemical education pose a communication problem for chemists. Unlike the findings from other specializations in chemistry the findings in chemical education tend to be reported in education journals that are not readily accessible to most chemists or chemistry teachers. This lecture is an attempt to remedy this gap in communication. Research studies fall into three broad categories. (i issues related to the content of chemistry itself, that is, What content to teach? And What meaning of each topic is to be conveyed? (ii issues related to how chemical content is taught, such as, the role of lectures, practical work, particular pedagogies, etc. and (iii issues related to its learning, that is, learning of concepts, conceptual change, motivation, etc. Findings in each of these categories of research over the last twenty years have drawn attention to opportunities for improving the quality of chemical education in each of the levels of formal education where chemistry is taught. Sometimes the research findings seem small since they, in fact, merely diagnose the actual problem in teaching and learning. At other times, the research findings are large because they provide a solution to these problems. What remains to be done is to disseminate the findings so that appropriate teaching occurs more widely, with its consequent gains in the quality of learning. Research findings, of these small and large types will be used to illustrate the potential of research to make the practice of chemical education more effective.