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Sample records for chemical shimming

  1. Dynamic B0 shimming at 7 T.

    Science.gov (United States)

    Sengupta, Saikat; Welch, E Brian; Zhao, Yansong; Foxall, David; Starewicz, Piotr; Anderson, Adam W; Gore, John C; Avison, Malcolm J

    2011-05-01

    Dynamic slice-wise shimming improves B0 field homogeneity by updating shim coil currents for every slice in a multislice acquisition, producing better field homogeneity over a volume than can be obtained by a single static global shim. The first aim of this work was to evaluate the performance of slice-wise field-map-based second-order dynamic shimming in a human high-field 7 T clinical scanner vis-à-vis image based second order static global shimming. Another goal was to characterize eddy currents induced by second and third order shim switching. A final aim was to compare global and dynamic shimming through shim orders to elucidate the relative benefits of going to higher orders and to dynamic shim updating from a static shimming regime. An external hardware module was used to store and dynamically update slice-optimized shim values during multislice data acquisition. High-bandwidth multislice gradient echo scans with B0 field mapping and low-bandwidth single-shot echo planar scans were performed on phantoms and humans using second-order dynamic and static global shims. For the measurement of second and third order shim induced eddy currents, step response temporal phase changes of individual shims were measured and fit to shim harmonics spatially and to multiexponential decay functions temporally. Finally, an order-wise field-map-based comparison was performed with first, second and third order global static shimming, first and second order dynamic shimming, as well as combined second or third order global and first order dynamic shim. Dynamic shimming considerably improved B0 homogeneity compared to static global shimming both in phantoms and in human subjects, reducing image distortion and signal dropout. The unshielded second and third order shims generated strong B0 and self and cross-term eddy fields, with multiple time constants ranging from milliseconds to seconds. Field homogeneity improved with increasing order of shim, with dynamic shimming performing

  2. Installation of Shimming Bars for CYCIAE-100

    Institute of Scientific and Technical Information of China (English)

    LV; Yin-long; WANG; Zhen-hui; ZHONG; Jun-qing; LIU; Geng-shou

    2012-01-01

    <正>The 100 MeV high intensity proton cyclotron, CYCIAE-100, is the most critical equipment of the BRIF project at CIAE. The shimming bars are used to get the isochronous magnetic field. In the process of magnetic mapping and shimming, the bars should be repeated the installed and disassembly for about 10 times. Each time the installation precision must be ensured. The bars installation schedule and quality are directly related to the BRIF project progress.

  3. Multipole shimming of permanent magnets using harmonic corrector rings.

    Science.gov (United States)

    Jachmann, R C; Trease, D R; Bouchard, L-S; Sakellariou, D; Martin, R W; Schlueter, R D; Budinger, T F; Pines, A

    2007-03-01

    Shimming systems are required to provide sufficient field homogeneity for high resolution nuclear magnetic resonance (NMR). In certain specialized applications, such as rotating-field NMR and mobile ex situ NMR, permanent magnet-based shimming systems can provide considerable advantages. We present a simple two-dimensional shimming method based on harmonic corrector rings which can provide arbitrary multipole order shimming corrections. Results demonstrate, for example, that quadrupolar order shimming improves the linewidth by up to an order of magnitude. An additional order of magnitude reduction is in principle achievable by utilizing this shimming method for z-gradient correction and higher order xy gradients.

  4. Integrated RF/shim coil array for parallel reception and localized B0 shimming in the human brain.

    Science.gov (United States)

    Truong, Trong-Kha; Darnell, Dean; Song, Allen W

    2014-12-01

    The purpose of this work was to develop a novel integrated radiofrequency and shim (RF/shim) coil array that can perform parallel reception and localized B0 shimming in the human brain with the same coils, thereby maximizing both the signal-to-noise ratio and shimming efficiency. A 32-channel receive-only head coil array was modified to enable both RF currents (for signal reception) and direct currents (for B0 shimming) to flow in individual coil elements. Its in vivo performance was assessed in the frontal brain region, which is affected by large susceptibility-induced B0 inhomogeneities. The coil modifications did not reduce their quality factor or signal-to-noise ratio. Axial B0 maps and echo-planar images acquired in vivo with direct currents optimized to shim specific slices showed substantially reduced B0 inhomogeneities and image distortions in the frontal brain region. The B0 root-mean-square error in the anterior half of the brain was reduced by 60.3% as compared to that obtained with second-order spherical harmonic shimming. These results demonstrate that the integrated RF/shim coil array can perform parallel reception and localized B0 shimming in the human brain and provide a much more effective shimming than conventional spherical harmonic shimming alone, without taking up additional space in the magnet bore and without compromising the signal-to-noise ratio or shimming performance.

  5. AA, shims and washers on quadrupole ends

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    Due to the fact that much of the field of the quadrupoles was outside the iron (in particular with the wide quadrupoles) and that thus the fields of quadrupoles and bending magnets interacted, the lattice properties of the AA could not be predicted with the required accuracy. After a first running period in 1980, during which detailed measurements were made with proton test beams, corrections to the quadrupoles were made in 1981, in the form of laminated shims at the ends of the poles, and with steel washers. With the latter ones, further refinements were made in an iterative procedure with measurements on the circulating beam. This eventually resulted, amongst other things, in a very low chromaticity, with the Q-values being constant to within +- 0.001 over the total momentum range of 6 %. Here we see the shims and washers on a narrow qudrupole (QFN, QDN). See also 8103203, 8103204, 8103205, 8103206.

  6. SHIMS -- A Spatial Heterodyne Interferometer for Methane Sounding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project develops the Spatial Heterodyne Interferometer for Methane Sounding (SHIMS), a lightweight, compact, robust spectrometer system for remote sensing of...

  7. Effect of Shim Arm Depletion in the NBSR

    Energy Technology Data Exchange (ETDEWEB)

    Hanson A. H.; Brown N.; Diamond, D.J.

    2013-02-22

    The cadmium shim arms in the NBSR undergo burnup during reactor operation and hence, require periodic replacement. Presently, the shim arms are replaced after every 25 cycles to guarantee they can maintain sufficient shutdown margin. Two prior reports document the expected change in the 113Cd distribution because of the shim arm depletion. One set of calculations was for the present high-enriched uranium fuel and the other for the low-enriched uranium fuel when it was in the COMP7 configuration (7 inch fuel length vs. the present 11 inch length). The depleted 113Cd distributions calculated for these cores were applied to the current design for an equilibrium low-enriched uranium core. This report details the predicted effects, if any, of shim arm depletion on the shim arm worth, the shutdown margin, power distributions and kinetics parameters.

  8. Magnetic field shimming of a permanent magnet using a combination of pieces of permanent magnets and a single-channel shim coil for skeletal age assessment of children.

    Science.gov (United States)

    Terada, Y; Kono, S; Ishizawa, K; Inamura, S; Uchiumi, T; Tamada, D; Kose, K

    2013-05-01

    We adopted a combination of pieces of permanent magnets and a single-channel (SC) shim coil to shim the magnetic field in a magnetic resonance imaging system dedicated for skeletal age assessment of children. The target magnet was a 0.3-T open and compact permanent magnet tailored to the hand imaging of young children. The homogeneity of the magnetic field was first improved by shimming using pieces of permanent magnets. The residual local inhomogeneity was then compensated for by shimming using the SC shim coil. The effectiveness of the shimming was measured by imaging the left hands of human subjects and evaluating the image quality. The magnetic resonance images for the child subject clearly visualized anatomical structures of all bones necessary for skeletal age assessment, demonstrating the usefulness of combined shimming.

  9. A SQP optimization method for shimming a permanent MRI magnet

    Institute of Scientific and Technical Information of China (English)

    Zhe Jin; Xing Tang; Bin Meng; Donglin Zu; Weimin Wang

    2009-01-01

    Based on the sequential quadratic programming (SQP) method, a new approach is presented in this paper to gain a uniform magnetic field for a permanent MRI magnet with biplanar poles. First, the adopted shimming piece is modeled as a magnetic dipole moment to calculate its effect on the background field over the imaging region of interest. Then, the SQP method is utilized to determine the ideal solution for the shimming equation. Finally, the ideal solution is discrete, and the quantization error control technique is used for special cases. This new method helps to reduce the inhomogeneity from 1234.5 ppm to 21.4 ppm over a 36 cm diameter spherical volume (DSV), within hours in practical shimming work.

  10. [Mechanical Shimming Method and Implementation for Permanent Magnet of MRI System].

    Science.gov (United States)

    Xue, Tingqiang; Chen, Jinjun

    2015-03-01

    A mechanical shimming method and device for permanent magnet of MRI system has been developed to meet its stringent homogeneity requirement without time-consuming passive shimming on site, installation and adjustment efficiency has been increased.

  11. Phase error reduction in superconductive undulators using induction shimming

    Energy Technology Data Exchange (ETDEWEB)

    Drayer, Elisabeth; Bernhard, Axel; Afonso Rodriguez, Veronica; Grau, Andreas; Peiffer, Peter; Widmann, Christina; Baumbach, Tilo [KIT, Karlsruhe (Germany)

    2013-07-01

    The reduction of field errors in superconductive undulators is more demanding than in room temperature permanent magnet undulators. Various basic concepts exist but most of them have the disadvantage that they require field measurements at liquid-Helium temperature and modifications of the undulator coils at room temperature. Thus one or more thermal cycles are needed for an iterative improvement of the field quality. In order to avoid such a procedure it was proposed to cover the undulator coils with a thin layer of coupled superconductive loops which passively compensate the field errors via induction of persistent correction currents. In previous measurements this concept proved to work in principle and conclusions on an optimised shim configuration and field measurement setup could be drawn. In this paper we present the results of new measurements using one 12-period superconductive undulator short model and applying an optimised induction shim configuration. Due to further improvements of the field measurement setup these experiments for the first time give a quantitative indication of the phase error reduction efficiency of induction shimming.

  12. Polar-drive experiments with shimmed targets on OMEGA

    Science.gov (United States)

    Marshall, F. J.; Radha, P. B.; Bonino, M. J.; Delettrez, J. A.; Epstein, R.; Skupsky, S.; Giraldez, E.

    2012-10-01

    Polar-drive experiments are being performed on OMEGA in preparation for future ignition attempts using the same method on the National Ignition Facility. This work presents results from a series of experiments employing shimmed shells whose shape (thinner at the target equator) is used to further compensate for the oblique illumination present in the polar-drive beam configuration. Implosion experiments were performed with multiple-picket laser pulses from 40 OMEGA beams driving gas-filled, shimmed shells. The implosions were diagnosed with x-ray backlighting, fusion yield, and reaction particle spectra from which the implosion symmetry, areal density, and core conditions are inferred. The compressed shell shape determined from framed x-ray radiography is compared to that predicted by the 2-D hydrodynamics code DRACO. The benefits of using a shimmed target for polar-drive implosions are less oblique illumination, better low-mode implosion symmetry, and are clearly demonstrated by these experiments. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

  13. Passive shimming of a superconducting magnet using the L1-norm regularized least square algorithm.

    Science.gov (United States)

    Kong, Xia; Zhu, Minhua; Xia, Ling; Wang, Qiuliang; Li, Yi; Zhu, Xuchen; Liu, Feng; Crozier, Stuart

    2016-02-01

    The uniformity of the static magnetic field B0 is of prime importance for an MRI system. The passive shimming technique is usually applied to improve the uniformity of the static field by optimizing the layout of a series of steel shims. The steel pieces are fixed in the drawers in the inner bore of the superconducting magnet, and produce a magnetizing field in the imaging region to compensate for the inhomogeneity of the B0 field. In practice, the total mass of steel used for shimming should be minimized, in addition to the field uniformity requirement. This is because the presence of steel shims may introduce a thermal stability problem. The passive shimming procedure is typically realized using the linear programming (LP) method. The LP approach however, is generally slow and also has difficulty balancing the field quality and the total amount of steel for shimming. In this paper, we have developed a new algorithm that is better able to balance the dual constraints of field uniformity and the total mass of the shims. The least square method is used to minimize the magnetic field inhomogeneity over the imaging surface with the total mass of steel being controlled by an L1-norm based constraint. The proposed algorithm has been tested with practical field data, and the results show that, with similar computational cost and mass of shim material, the new algorithm achieves superior field uniformity (43% better for the test case) compared with the conventional linear programming approach.

  14. Still shimming or already measuring? - Quantitative reaction monitoring for small molecules on the sub minute timescale by NMR

    Science.gov (United States)

    Kind, J.; Thiele, C. M.

    2015-11-01

    In order to enable monitoring of rapidly occurring reactions Wagner et al. recently presented a simple scheme for 1D NMR experiments with continuous data acquisition, without inter-scan delays, using a spatially-selective and frequency-shifted excitation approach (Wagner et al., 2013). This scheme allows acquisition of proton spectra with temporal resolutions on the millisecond timescale. Such high temporal resolutions are desired in the case of reaction monitoring using stopped flow setups. In regular 1H NMR-spectra without spatial selection the line width increases for a given shim setting with changes in sample volume, susceptibility, convection and temperature or concentration gradients due to the disturbance of magnetic field homogeneity. Concerning reaction monitoring this is unfortunate as shimming prior to acquisition becomes necessary to obtain narrow signals after injection of a reactant into an NMR sample. Even automatic shim routines may last up to minutes. Thus fast reactions can hardly be monitored online without large hardware dead times in a single stopped flow experiment. This problem is reduced in the spatially-selective and frequency-shifted continuous NMR experiment as magnetic field inhomogeneties are less pronounced and negative effects on the obtained line shapes are reduced as pointed out by Bax and Freeman (1980) [2] and demonstrated by Wagner et al. (2013). Here we present the utilization of this technique for observation of reactions in small molecule systems in which chemical conversion and longitudinal relaxation occur on the same timescale. By means of the alkaline ethyl acetate hydrolysis, a stoichiometric reaction, we show advantages of spatially-selective excitation on both temporal resolution and line shapes in stopped flow experiments. Results are compared to data obtained by non-selective small angle excitation experiments.

  15. Enabling Object Storage via shims for Grid Middleware

    CERN Document Server

    Skipsey, Samuel Cadellin; Dewhurst, Alastair; Britton, David; Roy, Gareth; Crooks, David

    2015-01-01

    The Object Store model has quickly become the basis of most commercially successful mass storage infrastructure, backing so-called "Cloud" storage such as Amazon S3, but also underlying the implementation of most parallel distributed storage systems. Many of the assumptions in Object Store design are similar, but not identical, to concepts in the design of Grid Storage Elements, although the requirement for "POSIX-like" filesystem structures on top of SEs makes the disjunction seem larger. As modern Object Stores provide many features that most Grid SEs do not (block level striping, parallel access, automatic file repair, etc.), it is of interest to see how easily we can provide interfaces to typical Object Stores via plugins and shims for Grid tools, and how well experiments can adapt their data models to them. We present evaluation of, and first-deployment experiences with, (for example) Xrootd-Ceph interfaces for direct object-store access, as part of an initiative within GridPP\\cite{GridPP} hosted at RAL....

  16. Enabling Object Storage via shims for Grid Middleware

    Science.gov (United States)

    Cadellin Skipsey, Samuel; De Witt, Shaun; Dewhurst, Alastair; Britton, David; Roy, Gareth; Crooks, David

    2015-12-01

    The Object Store model has quickly become the basis of most commercially successful mass storage infrastructure, backing so-called ”Cloud” storage such as Amazon S3, but also underlying the implementation of most parallel distributed storage systems. Many of the assumptions in Object Store design are similar, but not identical, to concepts in the design of Grid Storage Elements, although the requirement for ”POSIX-like” filesystem structures on top of SEs makes the disjunction seem larger. As modern Object Stores provide many features that most Grid SEs do not (block level striping, parallel access, automatic file repair, etc.), it is of interest to see how easily we can provide interfaces to typical Object Stores via plugins and shims for Grid tools, and how well experiments can adapt their data models to them. We present evaluation of, and first-deployment experiences with, (for example) Xrootd-Ceph interfaces for direct object-store access, as part of an initiative within GridPP[1] hosted at RAL. Additionally, we discuss the tradeoffs and experience of developing plugins for the currently-popular Ceph parallel distributed filesystem for the GFAL2 access layer, at Glasgow.

  17. Mobility Impact on Session Survivability under the SHIM6 Protocol and Enhancement of its Rehoming Procedure

    Directory of Open Access Journals (Sweden)

    Amine Dhraief

    2011-11-01

    Full Text Available Multihoming is a solution that enables a fault-tolerant access to the Internet by configuring on each network entity several IP addresses associated with distinct ISPs. IPv6 natively allows end-hosts and end-sites to be multihomed where nodes and routers can have multiple IP addresses. However, a specific support is required to take full advantage of multihoming. The SHIM6 protocol provides such a support.We study in this paper to what extent the mobility impacts the SHIM6 protocol component in general and more specifically the context establishment as it is a \\textit{sine qua none} condition for session survivability. We focus on possible consequences of mobility before, during, and after the context establishment. We find that in some mobility scenarios, the SHIM6 context is never established and the session survivability cannot be ensured.

  18. Prediction of forming limit strains of thin foils using shim

    Science.gov (United States)

    Joshi, Sanket Vivek; Bade, Rohit A.; Narasimhan, K.

    2013-12-01

    Thin foils of metallic alloys find utility in metallic thermal protection systems, such as honeycomb structures. Understanding the formability of these thin foils becomes imperative so as to design accurate tooling and also to ensure mechanical robustness of the honeycomb structures during service. It has been found that, obtaining the precise limit strains of these foils directly using the conventional limiting dome test tooling is difficult, because of the excessive draw in and wrinkling that occurs during the punch travel, resulting in erroneous measurement or prediction of limit strains. To address this issue, the blank over blank stacking methodology was developed, which helped keep the draw-in and wrinkling at negligible and thus acceptable levels. Although the blank over blank stacking methodology offers a way to predict and measure limit strains, the same may not be accurate enough due to the effect the substrate properties may impose on the thin foil. To avoid this effect, a different methodology has been proposed herein, which uses a shim stacked over the blank to avoid draw in of these foil blanks and thus help accurate clamping of the blank between the die and blank holder. It is thus understood that either a critical local or global increase in the thickness of the blank material in and around the draw bead is essential to obtain effective clamping of foil and to avoid draw-in and wrinkling. Although, miniaturized hemispherical dome tests may be beneficial for obtaining limit strains as far as foils are concerned, the methodologies proposed herein provide a route to obtaining the same using available equipment, thus saving resources and time involved in development of new miniaturized testing devices. The forming limit strains of thin foils of IN 718 (inconel) alloy having a thickness of 50μm, C263 (nimonic) alloy having a thickness of 100μm and CP Ti (commercially pure titanium) having a thickness of 200μm have been predicted using this methodology

  19. Installation of the Main Magnet and Preliminary Results of Magnetic Mapping and Shimming for CYCIAE-100

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Tian-jue; LV; Yin-long; ZHONG; Jun-qing; XING; Jian-sheng; CAO; Lei; YANG; Jian-jun; WANG; Chuan; YAO; Hong-juan; CUI; Tao; LI; Ming; YIN; Zhi-guo; WANG; Zhen-hui; LIU; Geng-shou; LEI; Yu; ZOU; Jian; ZHAO; Jiang-bin

    2012-01-01

    <正>In 2012, the magnetic mapping and shimming for the main magnet of CYCIAE-100 has been carried out 4 times in the temporary building, realizing the goal of reducing the phase shift of the accelerating proton by 80%. A number of large scale equipments, including the main magnet, main coils, hydraulic elevating system, RF amplifier, magnetic mapper and vacuum chamber, have been in place for installation in the main building. The final stage magnetic mapping and shimming has started out as well.

  20. Effect of shim configuration on internal die flows for non-Newtonian coating liquids in slot coating process

    Science.gov (United States)

    Jin, Guang Lin; Ahn, Won-Gi; Kim, See Jo; Nam, Jaewook; Jung, Hyun Wook; Hyun, Jae Chun

    2016-05-01

    In this study, a strategy for designing optimal shim configuration inside a slot die is suggested to assure the uniform coating flow distribution of various non-Newtonian shear-thinning liquids at the die exit in a slot coating system. Flow patterns of non-Newtonian liquids inside the slot die, via three-dimensional computations, have been compared using various shim geometries which can adjust the flow region in a slot manifold. The rather non-uniform (parabolic) velocity distributions of shear-thinning liquids at the die exit under the basic shim condition could be effectively flattened by the modification of shim geometry without the change of die manifold structure. Dimensions of hybrid shims for controlling flow features at edge and center regions within slit channel are positively tuned, according to the shear-thinning level of coating liquids.

  1. A new gradient shimming method based on undistorted field map of B0 inhomogeneity.

    Science.gov (United States)

    Bao, Qingjia; Chen, Fang; Chen, Li; Song, Kan; Liu, Zao; Liu, Chaoyang

    2016-04-01

    Most existing gradient shimming methods for NMR spectrometers estimate field maps that resolve B0 inhomogeneity spatially from dual gradient-echo (GRE) images acquired at different echo times. However, the distortions induced by B0 inhomogeneity that always exists in the GRE images can result in estimated field maps that are distorted in both geometry and intensity, leading to inaccurate shimming. This work proposes a new gradient shimming method based on undistorted field map of B0 inhomogeneity obtained by a more accurate field map estimation technique. Compared to the traditional field map estimation method, this new method exploits both the positive and negative polarities of the frequency encoded gradients to eliminate the distortions caused by B0 inhomogeneity in the field map. Next, the corresponding automatic post-data procedure is introduced to obtain undistorted B0 field map based on knowledge of the invariant characteristics of the B0 inhomogeneity and the variant polarity of the encoded gradient. The experimental results on both simulated and real gradient shimming tests demonstrate the high performance of this new method.

  2. Shimming Halbach magnets utilizing genetic algorithms to profit from material imperfections.

    Science.gov (United States)

    Parker, Anna J; Zia, Wasif; Rehorn, Christian W G; Blümich, Bernhard

    2016-04-01

    In recent years, permanent magnet-based NMR spectrometers have resurfaced as low-cost portable alternatives to superconducting instruments. While the development of these devices as well as clever shimming methods have yielded impressive advancements, scaling the size of these magnets to miniature lengths remains a problem to be addressed. Here we present the results of a study of a discrete shimming scheme for NMR Mandhalas constructed from a set of individual magnet blocks. While our calculations predict a modest reduction in field deviation by a factor of 9.3 in the case of the shimmed ideal Mandhala, a factor of 28 is obtained in the case of the shimmed imperfect Mandhala. This indicates that imperfections of magnet blocks can lead to improved field homogeneity. We also present a new algorithm to improve the homogeneity of a permanent magnet assembly. Strategies for future magnet construction can improve the agreement between simulation and practical implementation by using data from real magnets in these assemblies as the input to such an algorithm to optimize the homogeneity of a given design.

  3. A new gradient shimming method based on undistorted field map of B0 inhomogeneity

    Science.gov (United States)

    Bao, Qingjia; Chen, Fang; Chen, Li; Song, Kan; Liu, Zao; Liu, Chaoyang

    2016-04-01

    Most existing gradient shimming methods for NMR spectrometers estimate field maps that resolve B0 inhomogeneity spatially from dual gradient-echo (GRE) images acquired at different echo times. However, the distortions induced by B0 inhomogeneity that always exists in the GRE images can result in estimated field maps that are distorted in both geometry and intensity, leading to inaccurate shimming. This work proposes a new gradient shimming method based on undistorted field map of B0 inhomogeneity obtained by a more accurate field map estimation technique. Compared to the traditional field map estimation method, this new method exploits both the positive and negative polarities of the frequency encoded gradients to eliminate the distortions caused by B0 inhomogeneity in the field map. Next, the corresponding automatic post-data procedure is introduced to obtain undistorted B0 field map based on knowledge of the invariant characteristics of the B0 inhomogeneity and the variant polarity of the encoded gradient. The experimental results on both simulated and real gradient shimming tests demonstrate the high performance of this new method.

  4. Theoretical Formula and Simulation of Cyclotron Magnet Shimming in High Field Environment

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Dong-sheng; YANG; Jian-jun; LI; Ming

    2015-01-01

    In the computation of cyclotron magnet shimming,trim-rod and magnetic channel,one common process is to calculate the variation of magnet field caused by a small iron piece.Under the circumstance of superconducting cyclotron,high field approximate can be used and we can derive

  5. Mitigating the impact of hohlraum asymmetries in National Ignition Facility implosions using capsule shims

    Science.gov (United States)

    Clark, D. S.; Weber, C. R.; Smalyuk, V. A.; Robey, H. F.; Kritcher, A. L.; Milovich, J. L.; Salmonson, J. D.

    2016-07-01

    Current indirect drive implosion experiments on the National Ignition Facility (NIF) [Moses et al., Phys. Plasmas 16, 041006 (2009)] are believed to be strongly impacted by long wavelength perturbations driven by asymmetries in the hohlraum x-ray flux. To address this perturbation source, active efforts are underway to develop modified hohlraum designs with reduced asymmetry imprint. An alternative strategy, however, is to modify the capsule design to be more resilient to a given amount of hohlraum asymmetry. In particular, the capsule may be deliberately misshaped, or "shimmed," so as to counteract the expected asymmetries from the hohlraum. Here, the efficacy of capsule shimming to correct the asymmetries in two recent NIF implosion experiments is assessed using two-dimensional radiation hydrodynamics simulations. Despite the highly time-dependent character of the asymmetries and the high convergence ratios of these implosions, simulations suggest that shims could be highly effective at counteracting current asymmetries and result in factors of a few enhancements in neutron yields. For higher compression designs, the yield improvement could be even greater.

  6. Mitigating the impact of hohlraum asymmetries in National Ignition Facility implosions using capsule shims

    Science.gov (United States)

    Clark, Daniel; Weber, Christopher; Smalyuk, Vladimir; Robey, Harry; Kritcher, Andrea; Milovich, Jose; Salmonson, Jay

    2016-10-01

    Current indirect drive implosion experiments on the National Ignition Facility (NIF) are believed to be strongly impacted by long wavelength perturbations driven by asymmetries in the hohlraum x-ray flux. To address this perturbation source, active efforts are underway to develop modified hohlraum designs with reduced asymmetry imprint. An alternative strategy, however, is to modify the capsule design to be more resilient to a given amount of hohlraum asymmetry. In particular, the capsule may be deliberately misshaped, or ``shimmed,'' so as to counteract the expected asymmetries from the hohlraum. Here, the efficacy of capsule shimming to correct the asymmetries in two recent NIF implosion experiments is assessed using two-dimensional radiation hydrodynamics simulations. Despite the highly time-dependent character of the asymmetries and the high convergence ratios of these implosions, simulations suggest that shims could be highly effective at counteracting current asymmetries and result in factors of a few enhancements in neutron yields. For higher compression designs, the yield improvement could be even greater. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Comparison of volume-selective z-shim and conventional EPI in fMRI studies using face stimuli

    CERN Document Server

    Fukunaga, Hu Cheng Srikanth Padmala Rena

    2013-01-01

    Single-shot gradient recalled echo planar imaging (EPI) is the primary tool for functional magnetic resonance imaging (fMRI). The image often suffers from signal drop near the air-tissue interface, such as the amygdala and regions of the orbitofrontal lobe. An effective way to correct for this type of artifact is by applying multi-shot EPI using different z-shimming. Unfortunately, the scanning efficiency is significantly lowered. More recently, a new technique called volume-selective z-shim was proposed to implement z-shim compensation to only specific slices with large susceptibility effects. The high imaging efficiency of volume selective z-shim makes it possible to substitute conventional EPI for whole brain studies. In this study two fMRI experiments were conducted to compare volume- selective z-shim and conventional EPI while subjects performed tasks on face stimuli. The comparison was focused on three brain regions: amygdala, hippocampus, and fusiform gyrus. Our results indicate that despite fewer volu...

  8. B1 homogeneity of breast MRI using RF shimming with individual specific values in volunteers simulating patients after mastectomy.

    Science.gov (United States)

    Abe, Takayuki

    2016-11-01

    Background Magnetic resonance imaging (MRI) using a 3-T MRI scanner is now widely used for clinical examinations. However, B1 inhomogeneity becomes larger with MRI scanners using 3-T and higher. It especially becomes a problem in the breast. To improve B1 homogeneity, a RF shimming technique has been developed. Purpose To evaluate the B1 homogeneity of breast MRI using RF shimming with individual specific values for subjects after mastectomy. Material and Methods The subjects are healthy female volunteers who underwent normal breast imaging, followed by imaging of one breast while the other breast was bound tightly to the chest by bleached cotton cloths (simulating volunteers after mastectomy). B1 mappings were performed with RF shimming using two techniques: (i) optimized fixed value; and (ii) individual specific values using a 3-T MRI scanner. The means and standard deviations of the B1 maps for all slices in the breast were measured and compared between the fixed value and the individual specific value cases. Results For normal volunteers, the breast B1 variation was not statistically significantly different between the RF shimming techniques. For volunteers after simulated surgery, the breast B1 variation was (1.02 ± 0.29) with the fixed value and (0.98 ± 0.22) with the individual specific value ( P volunteers after simulated surgery. Conclusion RF shimming with individual specific values has the potential to improve the B1 homogeneity of breast MRI in patients after mastectomy.

  9. Quantitative Comparison of Minimum Inductance and Minimum Power Algorithms for the Design of Shim Coils for Small Animal Imaging.

    Science.gov (United States)

    Hudson, Parisa; Hudson, Stephen D; Handler, William B; Scholl, Timothy J; Chronik, Blaine A

    2010-04-01

    High-performance shim coils are required for high-field magnetic resonance imaging and spectroscopy. Complete sets of high-power and high-performance shim coils were designed using two different methods: the minimum inductance and the minimum power target field methods. A quantitative comparison of shim performance in terms of merit of inductance (ML) and merit of resistance (MR) was made for shim coils designed using the minimum inductance and the minimum power design algorithms. In each design case, the difference in ML and the difference in MR given by the two design methods was inductance designs tend to feature oscillations within the current density; while minimum power designs tend to feature less rapidly varying current densities and lower power dissipation. Overall, the differences in coil performance obtained by the two methods are relatively small. For the specific case of shim systems customized for small animal imaging, the reduced power dissipation obtained when using the minimum power method is judged to be more significant than the improvements in switching speed obtained from the minimum inductance method.

  10. Variable power combiner for RF mode shimming in 7-T MR imaging.

    Science.gov (United States)

    Yazdanbakhsh, Pedram; Solbach, Klaus; Bitz, Andreas K

    2012-09-01

    This contribution discusses the utilization of RF power in an MRI system with RF mode shimming which enables the superposition of circularly polarized modes of a transmit RF coil array driven by a Butler matrix. Since the required power for the individual modes can vary widely, mode-shimming can result in a significant underutilization of the total available RF power. A variable power combiner (VPC) is proposed to improve the power utilization: it can be realized as a reconfiguration of the MRI transmit system by the inclusion of one additional matrix network which receives the power from all transmit amplifiers at its input ports and provides any desired (combined) power distribution at its output ports by controlling the phase and amplitude of the amplifiers' input signals. The power distribution at the output ports of the VPC is then fed into the "mode" ports of the coil array Butler matrix in order to superimpose the spatial modes at the highest achievable power utilization. The VPC configuration is compared to the standard configuration of the transmit chain of our MRI system with 8 transmit channels and 16 coils. In realistic scenarios, improved power utilization was achieved from 17% to 60% and from 14% to 55% for an elliptical phantom and a region of interest in the abdomen, respectively, and an increase of the power utilization of 1 dB for a region of interest in the upper leg. In general, it is found that the VPC allows significant improvement in power utilization when the shimming solution demands only a few modes to be energized, while the technique can yield loss in power utilization in cases with many modes required at high power level.

  11. SENSE shimming (SSH): A fast approach for determining B(0) field inhomogeneities using sensitivity coding.

    Science.gov (United States)

    Splitthoff, D N; Zaitsev, M

    2009-11-01

    The pursuit of ever higher field strengths and faster data acquisitions has led to the construction of coil arrays with high numbers of elements. With the sensitivity encoding (SENSE) technique, it has been shown that the sensitivity of those elements can be used for spatial image encoding. Here, a proof-of-principle is presented of a method that can be considered an extreme case of the SENSE approach, completely abstaining from using encoding gradients. The resulting sensitivity encoded free-induction decay (FID) data are then not used for imaging, but for determining B(0) field inhomogeneity distribution. The method has therefore been termed "SENSE shimming" (SSH). In phantom experiments the method's ability to detect inhomogeneities of up to the second order is demonstrated.

  12. Gain of Imaging Fidelity by Employing a Higher Number of Independent Transmit Channels Together with Slice-Selective Radio-Frequency (RF Shimming at 7T

    Directory of Open Access Journals (Sweden)

    Niravkumar Darji

    2013-12-01

    Full Text Available Dielectric resonance effects and radio-frequency (RF power deposition have become challenging issues for magnetic resonance imaging at ultrahigh-field (UHF strengths. The use of transmit (Tx coil arrays with independently-driven RF sources using a parallel transmission system is a promising method for alleviating the resulting RF inhomogeneities. In this study, the effect on homogeneity and RF-power when employing a higher number of transmit channels with multi-slice acquisition in vivo at high field strength (7T is scrutinized. An 8-channel head coil array was driven to emulate circular polarized (CP and 2-, 4-, and 8-channel independent transmit configurations at 7T. Static RF shimming was employed on human subjects in order to homogenize the B1+ field in the excited volume. Slice-selective and global RF shimming methods were applied with CP and 2-, 4-, and 8-channel transmit channel configurations. RF shimming was performed from CP to 2-, 4-, and 8-channel Tx configurations globally and slice-selectively. Systematic improvement in B1+ homogeneity and/or reduction in RF-power were observed. RF shimming in the human brain with 8-channel transmit and slice-selective shimming yields an increase in B1+ homogeneity of 43% and/or reduces RF-power by 68% when compared with CP global RF shimming at 7T.

  13. Magnetic levitation performance of high-temperature superconductor over three magnetic hills of permanent magnet guideway with iron shims of different thicknesses

    Institute of Scientific and Technical Information of China (English)

    Yuming Gong; Gang Liang; Lifeng Zhao; Yong Zhang; Yong Zhao; Xuyong Chen

    2014-01-01

    Superconducting magnetic levitation perfor-mance, including levitation force and guidance force, is important for the application of high-temperature super-conducting maglev. Both of them are not only affected by different arrays of superconductors and magnets, but also by the thickness of the iron shim between permanent magnets. In order to obtain the best levitation performance, the magnetic field distribution, levitation force, and guid-ance force of a new type of three magnetic hills of per-manent magnet guideway with iron shim of different thicknesses (4, 6, and 8 mm) are discussed in this paper. Simulation analysis and experiment results show that the guideway with iron shim of 8 mm thickness possesses the strongest magnetic field and levitation performance when the suspension gap is larger than 10 mm. However, with the decreasing of suspension gap, the guideway with iron shim of 4 mm thickness possesses the best levitation per-formance. The phenomena can be attributed to the density distribution of flux and magnetization of iron shim.

  14. Shimming with permanent magnets for the x-ray detector in a hybrid x-ray/ MR system.

    Science.gov (United States)

    Wen, Zhifei; Fahrig, Rebecca; Williams, Scott T; Pelc, Norbert J

    2008-09-01

    In this x-ray/MR hybrid system an x-ray flat panel detector is placed under the patient cradle, close to the MR volume of interest (VOI), where the magnetic field strength is approximately 0.5 T. Immersed in this strong field, several electronic components inside the detector become magnetized and create an additional magnetic field that is superimposed on the original field of the MR scanner. Even after linear shimming, the field homogeneity of the MR scanner remains disrupted by the detector. The authors characterize the field due to the detector with the field of two magnetic dipoles and further show that two sets of permanent magnets (NdFeB) can withstand the main magnetic field and compensate for the nonlinear components of the additional field. The ideal number of magnets and their locations are calculated based on a field map measured with the detector in place. Experimental results demonstrate great promise for this technique, which may be useful in many settings where devices with magnetic components need to be placed inside or close to an MR scanner.

  15. Structural shimming for high-resolution nuclear magnetic resonance spectroscopy in lab-on-a-chip devices.

    Science.gov (United States)

    Ryan, Herbert; Smith, Alison; Utz, Marcel

    2014-05-21

    High-resolution proton NMR spectroscopy is well-established as a tool for metabolomic analysis of biological fluids at the macro scale. Its full potential has, however, not been realised yet in the context of microfluidic devices. While microfabricated NMR detectors offer substantial gains in sensitivity, limited spectral resolution resulting from mismatches in the magnetic susceptibility of the sample fluid and the chip material remains a major hurdle. In this contribution, we show that susceptibility broadening can be avoided even in the presence of substantial mismatch by including suitably shaped compensation structures into the chip design. An efficient algorithm for the calculation of field maps from arbitrary chip layouts based on Gaussian quadrature is used to optimise the shape of the compensation structure to ensure a flat field distribution inside the sample area. Previously, the complexity of microfluidic NMR systems has been restricted to simple capillaries to avoid susceptibility broadening. The structural shimming approach introduced here can be adapted to virtually any shape of sample chamber and surrounding fluidic network, thereby greatly expanding the design space and enabling true lab-on-a-chip systems suitable for high-resolution NMR detection.

  16. 3D GABA imaging with real-time motion correction, shim update and reacquisition of adiabatic spiral MRSI.

    Science.gov (United States)

    Bogner, Wolfgang; Gagoski, Borjan; Hess, Aaron T; Bhat, Himanshu; Tisdall, M Dylan; van der Kouwe, Andre J W; Strasser, Bernhard; Marjańska, Małgorzata; Trattnig, Siegfried; Grant, Ellen; Rosen, Bruce; Andronesi, Ovidiu C

    2014-12-01

    Gamma-aminobutyric acid (GABA) and glutamate (Glu) are the major neurotransmitters in the brain. They are crucial for the functioning of healthy brain and their alteration is a major mechanism in the pathophysiology of many neuro-psychiatric disorders. Magnetic resonance spectroscopy (MRS) is the only way to measure GABA and Glu non-invasively in vivo. GABA detection is particularly challenging and requires special MRS techniques. The most popular is MEscher-GArwood (MEGA) difference editing with single-voxel Point RESolved Spectroscopy (PRESS) localization. This technique has three major limitations: a) MEGA editing is a subtraction technique, hence is very sensitive to scanner instabilities and motion artifacts. b) PRESS is prone to localization errors at high fields (≥3T) that compromise accurate quantification. c) Single-voxel spectroscopy can (similar to a biopsy) only probe steady GABA and Glu levels in a single location at a time. To mitigate these problems, we implemented a 3D MEGA-editing MRS imaging sequence with the following three features: a) Real-time motion correction, dynamic shim updates, and selective reacquisition to eliminate subtraction artifacts due to scanner instabilities and subject motion. b) Localization by Adiabatic SElective Refocusing (LASER) to improve the localization accuracy and signal-to-noise ratio. c) K-space encoding via a weighted stack of spirals provides 3D metabolic mapping with flexible scan times. Simulations, phantom and in vivo experiments prove that our MEGA-LASER sequence enables 3D mapping of GABA+ and Glx (Glutamate+Gluatmine), by providing 1.66 times larger signal for the 3.02ppm multiplet of GABA+ compared to MEGA-PRESS, leading to clinically feasible scan times for 3D brain imaging. Hence, our sequence allows accurate and robust 3D-mapping of brain GABA+ and Glx levels to be performed at clinical 3T MR scanners for use in neuroscience and clinical applications.

  17. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

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

  18. Two-voxel spectroscopy with dynamic B0 shimming and flip angle adjustment at 7 T in the human motor cortex.

    Science.gov (United States)

    Lemke, Clark; Hess, Aaron; Clare, Stuart; Bachtiar, Velicia; Stagg, Charlotte; Jezzard, Peter; Emir, Uzay

    2015-07-01

    The aim of this study was to acquire high-quality in vivo (1) H spectra concurrently from two voxels at ultra-high field (7 T) without specialized hardware. To this end, an acquisition scheme was developed in which first-order shims and flip angles are dynamically updated to acquire spectra from both of the brain's motor cortices in an alternating fashion. To validate this acquisition scheme, separate, static, single-voxel acquisitions were also performed for comparison. Six subjects were examined using semi-LASER spectroscopy at 7 T. Barium titanate pads were used to increase the extent of the effective transmit field (B1 (+) ). Spectra were obtained from the hand area of both motor cortices for both acquisition schemes. LCModel was used to determine neurochemical profiles in order to examine variations between acquisition schemes and volumes of interest. The dynamic two-voxel acquisition protocol produced water linewidths (full width at half-maximum between 11.6 and 12.8 Hz) and signal-to-noise ratios similar to those from static single-voxel measurements. The concentrations of 13 individual and 3 combined metabolites with Cramér-Rao lower bounds below 30% were reliably detected for both acquisition schemes, and agreed well with previous postmortem assay and spectroscopy studies. The results show that high spectral quality from two voxels can be acquired concurrently without specialized hardware. This practical technique can be applied to many neuroscience applications.

  19. 基于虚拟样机的回旋加速器主磁铁设计与修正%Magnet design and shimming of cyclotrons based on virtual prototyping

    Institute of Scientific and Technical Information of China (English)

    秦斌; 樊明武; 陈德智

    2007-01-01

    磁铁设计对于等时性回旋加速器极为关键.磁场分布需要满足粒子等时性加速和粒子径向、轴向聚集要求,同时避免危险的横向共振.提出了一种计算机辅助的自动化磁铁设计、建模和修正的方法,该方法在基于Python混合编程的虚拟样机集成设计环境中实现.详细描述了利用3维电磁场仿真软件TOSCA和自主开发的粒子束跟踪软件PTP对磁铁的优化过程,并给出了一个16 MeV负氢紧凑型回旋加速器的主磁铁设计实例.%Magnet design and modeling is a crucial task in the design of cyclotrons, which includes iterative processes from an initial model. The magnetic field distribution should fulfill the requirements of isochronisms and transverse focusing of the beam, as well as avoiding dangerous resonance crossing. This paper introduces an automated magnet design, modeling and shimming method under the pythonic integrated environment based on virtual prototyping, a novel technique to shorten development period and reduce costs for physical prototypes. Detailed magnet shimming processes with the support of the 3D magnetic field simulation code TOSCA and an original developed particle tracking code PTP are described. As a case study, the main magnet design of a 16 MeV H- compact isochronous cyclotron is illustrated and validated in a virtual prototype.

  20. Two-Dimensional Proton Chemical-Shift Imaging of Human Muscle Metabolites

    Science.gov (United States)

    Hu, Jiani; Willcott, M. Robert; Moore, Gregory J.

    1997-06-01

    Large lipid signals and strong susceptibility gradients introduced by muscle-bone interfaces represent major technical challenges forin vivoproton MRS of human muscle. Here, the demonstration of two-dimensional proton chemical-shift imaging of human muscle metabolites is presented. This technique utilizes a chemical-shift-selective method for water and lipid suppression and automatic shimming for optimal homogeneity of the magnetic field. The 2D1H CSI technique described facilitates the acquisition of high-spatial-resolution spectra, and allows one to acquire data from multiple muscle groups in a single experiment. A preliminary investigation utilizing this technique in healthy adult males (n= 4) revealed a highly significant difference in the ratio of the creatine to trimethylamine resonance between the fast and slow twitch muscle groups examined. The technique is robust, can be implemented on a commercial scanner with relative ease, and should prove to be a useful tool for both clinical and basic investigators.

  1. 液化石油气二甲醚混合燃料用橡胶密封圈安全性能的试验研究%Experimental Study on Safety Property of LPGDME Rubber Shim

    Institute of Scientific and Technical Information of China (English)

    徐晓丹; 万晓宁; 朱平; 郭培杰; 何华

    2012-01-01

    Taking fluorine rubber and Buna-N rubber seal for examples, and according to GB 7512-2006 Cylinders Valve of Liquefied Petroleum Gas and an enterprise standard Dimethyl Ether Rubber Seal Material, the corrosion-resisting test, the ageing resistance test and the low temperature resistance test were implemented in LPGDME with different proportioning. The test results indicate that both volume change rate and mass change rate of two samples can change with the ratio of dimethyl ether, but the mass change rate of Buna-N rubber can change obviously with the ratio change of combined fuel and the results of ageing resistance test and low temperature resistance test are acceptable. Under the same ratio of reagents, the corrosion resistance property of fluorine rubber outperforms that of common Buna-N Rubber, and the safety property of fluorine rubber shim can meet the standard requirements, and it' s applicable to LPGDME cylinder.%以氟橡胶和普通丁腈橡胶两种橡胶密封圈为样本,分别参照GB 7512-2006《液化石油气瓶阀》与某企业的《二甲醚类橡胶密封材料》规定,在不同配比下的液化石油气二甲醚混合燃料环境中进行橡胶密封圈耐腐蚀性、耐老化和耐低温试验.试验数据显示两种样本的体积变化率与质量变化率都随二甲醚配比的变化而变化,但普通丁腈橡胶的质量变化率随混合燃料配比的变化更明显;耐老化及耐低温试验均合格.相同配比的试剂下,氟橡胶的耐腐蚀性能优于普通丁腈橡胶,因此,氟橡胶安全性能试验符合标准规定,可适用于储存液化石油气二甲醚混合燃料的钢瓶瓶阀的密封材料.

  2. Intelligent Shimming for Deep Drawing Processes

    DEFF Research Database (Denmark)

    Tommerup, Søren; Endelt, Benny Ørtoft; Danckert, Joachim

    2011-01-01

    cavities the blank-holder force distribution can be controlled during the punch stroke. By means of a sequence of numerical simulations abrasive wear is imposed to the deep drawing of a rectangular cup. The abrasive wear is modelled by changing the tool surface geometry using an algorithm based...... on the sliding energy density. As the tool surfaces are changed the material draw-in is significantly altered when using conventional open-loop control of the blank-holder force. A feed-back controller is presented which is capable of reducing the draw-in difference to a certain degree. Further a learning...

  3. Chemical Emergencies

    Science.gov (United States)

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

  4. Chemical use

    Data.gov (United States)

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

  5. Chemical Reactors.

    Science.gov (United States)

    Kenney, C. N.

    1980-01-01

    Describes a course, including content, reading list, and presentation on chemical reactors at Cambridge University, England. A brief comparison of chemical engineering education between the United States and England is also given. (JN)

  6. Chemical sensors

    Science.gov (United States)

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1991-07-02

    Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

  7. Chemical intolerance

    DEFF Research Database (Denmark)

    Dantoft, Thomas Meinertz; Andersson, Linus; Nordin, Steven;

    2015-01-01

    Chemical intolerance (CI) is a term used to describe a condition in which the sufferer experiences a complex array of recurrent unspecific symptoms attributed to low-level chemical exposure that most people regard as unproblematic. Severe CI constitutes the distinguishing feature of multiple...... chemical sensitivity (MCS). The symptoms reported by CI subjects are manifold, involving symptoms from multiple organs systems. In severe cases of CI, the condition can cause considerable life-style limitations with severe social, occupational and economic consequences. As no diagnostic tools for CI...

  8. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

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

  9. 在体肝脏3.0T质子MRS匀场与抑水信度研究及相关分析%Reliability and correlation of in vivo heptic shimming of liver and water suppression with 3.0T proton MRS

    Institute of Scientific and Technical Information of China (English)

    徐莉; 梁长虹; 刘再毅; 赵振军; 黄飚; 曾琼新; 萧远球

    2009-01-01

    Objective To assess the reliability of auto-shimming line width (LW) and water suppression rate (WS), and the correlation between them. Methods GE Signa Excite HD 3.0T system and eight-channel torso phased-array coils with PRESS sequence were performed in 38 volunteers. Liver spectra were collected with TR of 1500 ms, TE of 30 ms, VOI of 2 cm×2 cm×2 cm, NSA of 64 times. Spectroscopy routine auto-shimming pre-scanning program was executed and the values of LW and WS were recorded. Then another spectroscopy routine auto-shimming pre-scanning program was performed repeatedly and 38 groups of data were obtained totally. Intra-class correlation coefficients (ICC), coefficient of variation (CV) and significance test were conduced on 38 groups of LW and WS data. Spearman rank correlation analysis was used to assess the correlation of LW and WS. Results ①The ICC of LW and WS was 0.862 and 0.961 (both P<0.0001), respectively, while the value of CV was 0.20, 0.18, 0.09 and 0.08, respectively. Significant difference was not observed; ②The value of correlation coefficient was -0.659, -0.485 (both P<0.0001), respectively. Conclusion ①The reliability is excellent for in vivo liver 3.0T 1H-MRS and WS appears relatively stable; ②Indexes of LW correlate with WS moderately, and it seems the smaller the value of LW is, the easier to achieve higher WS.%目的 探讨在体肝脏3.0T单体素PRESS序列质子MRS自动匀场线宽(LW)和抑水率(WS)的信度及二者的相关性.方法 采用GE Signa Excite HD 3.0T超导MR扫描仪,8通道相控阵线圈.1H-MRS采集参数为TR/TE 1500/30 ms,NSA 64,VOI 2 cm×2 cm×2 cm.波谱常规预扫描,记录LW和WS后进行波谱采集,然后重复执行一次得到另外一组LW及WS数据共计38组.计算两次LW和WS组内相关系数(ICC)、变异系数(CV)及两次重复测量结果之间的显著性,并对LW和WS行等级相关分析. 结果①前后两次波谱常规预扫描LW和WS的ICC分别为0.862、0.961(P均<0

  10. Chemical Mahjong

    Science.gov (United States)

    Cossairt, Travis J.; Grubbs, W. Tandy

    2011-01-01

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

  11. Chemical dispersants

    NARCIS (Netherlands)

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

    2016-01-01

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

  12. SHIM-Fire Breadboard Instrument Design, Integration, and First Measurements

    Science.gov (United States)

    2005-11-23

    of SHS is described in detail in publications by Harlander et al. [1992, 1994, 2003]. The concept is similar to a Michelson interferometer with the...34 Applied Optics, 41, 1343-1352, 2002. Harlander J.M., F.L. Roesler, C.R. Englert, J.G. Cardon, R.R. Conway, C.M. Brown, J. Wimperis, "Robust monolithic

  13. SHIM-Free Breadboard Instrument Design, Integration, and First Measurements

    Science.gov (United States)

    2005-11-23

    The concept is similar to a Michelson interferometer with the return mirrors replaced by fixed, tilted diffraction gratings. Figure 1 shows the basic...Cardon, R.R. Conway, C.M. Brown, J. Wimperis, "Robust monolithic ultraviolet interferometer for the SHIMMER instrument on STPSat-l," Applied Optics, 42

  14. Chemical carcinogenesis

    Directory of Open Access Journals (Sweden)

    Paula A. Oliveira

    2007-12-01

    Full Text Available The use of chemical compounds benefits society in a number of ways. Pesticides, for instance, enable foodstuffs to be produced in sufficient quantities to satisfy the needs of millions of people, a condition that has led to an increase in levels of life expectancy. Yet, at times, these benefits are offset by certain disadvantages, notably the toxic side effects of the chemical compounds used. Exposure to these compounds can have varying effects, ranging from instant death to a gradual process of chemical carcinogenesis. There are three stages involved in chemical carcinogenesis. These are defined as initiation, promotion and progression. Each of these stages is characterised by morphological and biochemical modifications and result from genetic and/or epigenetic alterations. These genetic modifications include: mutations in genes that control cell proliferation, cell death and DNA repair - i.e. mutations in proto-oncogenes and tumour suppressing genes. The epigenetic factors, also considered as being non-genetic in character, can also contribute to carcinogenesis via epigenetic mechanisms which silence gene expression. The control of responses to carcinogenesis through the application of several chemical, biochemical and biological techniques facilitates the identification of those basic mechanisms involved in neoplasic development. Experimental assays with laboratory animals, epidemiological studies and quick tests enable the identification of carcinogenic compounds, the dissection of many aspects of carcinogenesis, and the establishment of effective strategies to prevent the cancer which results from exposure to chemicals.A sociedade obtém numerosos benefícios da utilização de compostos químicos. A aplicação dos pesticidas, por exemplo, permitiu obter alimento em quantidade suficiente para satisfazer as necessidades alimentares de milhões de pessoas, condição relacionada com o aumento da esperança de vida. Os benefícios estão, por

  15. Chemical cosmology

    CERN Document Server

    Boeyens, Jan CA

    2010-01-01

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

  16. Chemical Analyses

    Science.gov (United States)

    Bulluck, J. W.; Rushing, R. A.

    1994-01-01

    As a preliminary study on the effects of chemical aging of polymer materials MERL and TRI have examined two polymeric materials that are typically used for offshore umbilical applications. These two materials were Tefzel, a copolymer of ethylene and tetrafluoroethylene, and Coflon, polyvinylidene fluoride. The Coflon specimens were cut from pipe sections and exposed to H2S at various temperatures and pressures. One of these specimens was tested for methane permeation, and another for H2S permeation. The Tefzel specimens were cut from .05 mm sheet stock material and were exposed to methanol at elevated temperature and pressure. One of these specimens was exposed to methanol permeation for 2 days at 100 C and 2500 psi. An additional specimen was exposed to liquid methanol for 3 days at 150 C and 15 Bar. Virgin specimens of each material were similarly prepared and tested.

  17. CHEMICAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Melvin

    1965-06-01

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

  18. Chemical information science coverage in Chemical Abstracts.

    Science.gov (United States)

    Wiggins, G

    1987-02-01

    For many years Chemical Abstracts has included in its coverage publications on chemical documentation or chemical information science. Although the bulk of those publications can be found in section 20 of Chemical Abstracts, many relevant articles were found scattered among 39 other sections of CA in 1984-1985. In addition to the scattering of references in CA, the comprehensiveness of Chemical Abstracts as a secondary source for chemical information science is called into question. Data are provided on the journals that contributed the most references on chemical information science and on the languages of publication of relevant articles.

  19. Nature's chemicals and synthetic chemicals: comparative toxicology.

    OpenAIRE

    Ames, B N; Profet, M; Gold, L S

    1990-01-01

    The toxicology of synthetic chemicals is compared to that of natural chemicals, which represent the vast bulk of the chemicals to which humans are exposed. It is argued that animals have a broad array of inducible general defenses to combat the changing array of toxic chemicals in plant food (nature's pesticides) and that these defenses are effective against both natural and synthetic toxins. Synthetic toxins such as dioxin are compared to natural chemicals, such as indole carbinol (in brocco...

  20. Microfluidic chemical reaction circuits

    Science.gov (United States)

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

    2012-06-26

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

  1. Chemical Security Analysis Center

    Data.gov (United States)

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

  2. The chemical life(1).

    Science.gov (United States)

    Hodges, Nathan

    2015-01-01

    You write this narrative autoethnography to open up a conversation about our chemical lives. You go through your day with chemical mindfulness, questioning taken-for-granted ideas about natural and artificial, healthy and unhealthy, dependency and addiction, trying to understand the chemical messages we consume through the experiences of everyday life. You reflect on how messages about chemicals influence and structure our lives and why some chemicals are celebrated and some are condemned. Using a second-person narrative voice, you show how the personal is relational and the chemical is cultural. You write because you seek a connection, a chemical bond.

  3. Existing chemicals: international activities.

    Science.gov (United States)

    Purchase, J F

    1989-01-01

    The standards of care used in the protection of the health and safety of people exposed to chemicals has increased dramatically in the last decade. Standards imposed by regulation and those adopted by industry have required a greater level of knowledge about the hazards of chemicals. In the E.E.C., the 6th amendment of the dangerous substances directive imposed the requirement that al new chemicals should be tested according to prescribed programme before introduction on to the market. The development of a European inventory of existing chemicals was an integral part of the 6th amendment. It has now become clear that increased standards of care referred to above must be applied to the chemicals on the inventory list. There is, however, a considerable amount of activity already under way in various international agencies. The OECD Chemicals Programme has been involved in considering the problem of existing chemicals for some time, and is producing a priority list and action programme. The International Programme on Chemical Safety produces international chemical safety cards, health and safety guides and environmental health criteria documents. The international register of potentially toxic compounds (part of UNEP) has prepared chemical data profiles on 990 compounds. The International Agency for Research on Cancer prepared monographs on the carcinogenic risk of chemicals to man. So far 42 volumes have been prepared covering about 900 substances. IARC and IPCS also prepare periodic reports on ongoing research on carcinogenicity or toxicity (respectively) of chemicals. The chemical industry through ECETOC (the European Chemical Industry Ecology and Toxicology Centre) has mounted a major initiative on existing chemicals. Comprehensive reviews of the toxicity of selected chemicals are published (Joint Assessment of Commodity Chemicals). In its technical report no. 30 ECETOC lists reviews and evaluations by major national and international organisations, which provides

  4. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2012-01-01

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

  5. Capacitive chemical sensor

    Science.gov (United States)

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

    2014-05-27

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

  6. Tobacco and chemicals (image)

    Science.gov (United States)

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

  7. Chemical Industry Bandwidth Study

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2006-12-01

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

  8. Chemical Search Web Utility

    Data.gov (United States)

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

  9. Chemicals Industry Vision

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1996-12-01

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

  10. Chemical Physics Courses.

    Science.gov (United States)

    Lee, J.; Munn, R. W.

    1978-01-01

    This is a guide to the chemical physics major. The scope of chemical physics is presented, along with the general features of course contents and possible course structures. This information was derived from a survey of British universities and colleges offering undergraduate degree courses in chemical physics. (BB)

  11. Chemical Recycle of Plastics

    Directory of Open Access Journals (Sweden)

    Sara Fatima

    2014-11-01

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

  12. Chemicals for worldwide aquaculture

    Science.gov (United States)

    Schnick, R.A.

    1991-01-01

    Regulations and therapeutants or other safe chemicals that are approved or acceptable for use in the aquaculture industry in the US, Canada, Europe and Japan are presented, discussing also compounds that are unacceptable for aquaculture. Chemical use practices that could affect public health are considered and details given regarding efforts to increase the number of registered and acceptable chemicals.

  13. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2012-01-01

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

  14. Advances in chemical Physics

    CERN Document Server

    Rice, Stuart A

    2011-01-01

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

  15. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2014-01-01

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

  16. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2011-01-01

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

  17. Chemical bond fundamental aspects of chemical bonding

    CERN Document Server

    Frenking, Gernot

    2014-01-01

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

  18. Hand chemical burns.

    Science.gov (United States)

    Robinson, Elliot P; Chhabra, A Bobby

    2015-03-01

    There is a vast and ever-expanding variety of potentially harmful chemicals in the military, industrial, and domestic landscape. Chemical burns make up a small proportion of all skin burns, yet they can cause substantial morbidity and mortality. Additionally, the hand and upper extremity are the most frequently involved parts of the body in chemical burns, and therefore these injuries may lead to severe temporary or permanent loss of function. Despite this fact, discussion of the care of these injuries is sparse in the hand surgery literature. Although most chemical burns require only first response and wound care, some require the attention of a specialist for surgical debridement and, occasionally, skin coverage and reconstruction. Exposure to certain chemicals carries the risk of substantial systemic toxicity and even mortality. Understanding the difference between thermal and chemical burns, as well as special considerations for specific compounds, will improve patient treatment outcomes.

  19. Chemical Biology is.....

    OpenAIRE

    2007-01-01

    Chemical Biology is a relatively new field, and as such is not yet simply or succinctly defined. It includes such a wide range of fundamental problems that this commentary could only include just a few snapshots of potential areas of interest. Overarching themes and selected recent successes and ideas in chemical biology are described to illustrate broadly the scope of the field, but should not be taken as exhaustive. The Chemical Biology Section of Chemistry Central Journal is pleased to rec...

  20. Multivariate Quantitative Chemical Analysis

    Science.gov (United States)

    Kinchen, David G.; Capezza, Mary

    1995-01-01

    Technique of multivariate quantitative chemical analysis devised for use in determining relative proportions of two components mixed and sprayed together onto object to form thermally insulating foam. Potentially adaptable to other materials, especially in process-monitoring applications in which necessary to know and control critical properties of products via quantitative chemical analyses of products. In addition to chemical composition, also used to determine such physical properties as densities and strengths.

  1. Introduction to chemical kinetics

    CERN Document Server

    Soustelle, Michel

    2013-01-01

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

  2. Laboratory of Chemical Physics

    Data.gov (United States)

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

  3. Chemical Processing Manual

    Science.gov (United States)

    Beyerle, F. J.

    1972-01-01

    Chemical processes presented in this document include cleaning, pickling, surface finishes, chemical milling, plating, dry film lubricants, and polishing. All types of chemical processes applicable to aluminum, for example, are to be found in the aluminum alloy section. There is a separate section for each category of metallic alloy plus a section for non-metals, such as plastics. The refractories, super-alloys and titanium, are prime candidates for the space shuttle, therefore, the chemical processes applicable to these alloys are contained in individual sections of this manual.

  4. Multiple chemical sensitivity

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  5. Chemical burn or reaction

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000059.htm Chemical burn or reaction To use the sharing features on this page, please enable JavaScript. Chemicals that touch skin can lead to a reaction on the skin, throughout the body, or both. ...

  6. Chemical warfare in freshwater

    NARCIS (Netherlands)

    Mulderij, Gabi

    2006-01-01

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

  7. Chemical Reactivity Test (CRT)

    Energy Technology Data Exchange (ETDEWEB)

    Zaka, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-13

    The Chemical Reactivity Test (CRT) is used to determine the thermal stability of High Explosives (HEs) and chemical compatibility between (HEs) and alien materials. The CRT is one of the small-scale safety tests performed on HE at the High Explosives Applications Facility (HEAF).

  8. Biobased chemicals from polyhydroxybutyrate

    NARCIS (Netherlands)

    Spekreijse, Jurjen

    2016-01-01

    Currently, most chemicals and materials are obtained from fossil resources. After use, these chemicals and materials are converted to CO2. As discussed in chapter 1, this causes a build-up of CO2 in the atmosphere, the main driving force of global warming. In order to reach a sustai

  9. Chemical recognition software

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-06-01

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

  10. Chemical recognition software

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-01

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

  11. Tortuous path chemical preconcentrator

    Science.gov (United States)

    Manginell, Ronald P.; Lewis, Patrick R.; Adkins, Douglas R.; Wheeler, David R.; Simonson, Robert J.

    2010-09-21

    A non-planar, tortuous path chemical preconcentrator has a high internal surface area having a heatable sorptive coating that can be used to selectively collect and concentrate one or more chemical species of interest from a fluid stream that can be rapidly released as a concentrated plug into an analytical or microanalytical chain for separation and detection. The non-planar chemical preconcentrator comprises a sorptive support structure having a tortuous flow path. The tortuosity provides repeated twists, turns, and bends to the flow, thereby increasing the interfacial contact between sample fluid stream and the sorptive material. The tortuous path also provides more opportunities for desorption and readsorption of volatile species. Further, the thermal efficiency of the tortuous path chemical preconcentrator is comparable or superior to the prior non-planar chemical preconcentrator. Finally, the tortuosity can be varied in different directions to optimize flow rates during the adsorption and desorption phases of operation of the preconcentrator.

  12. Chemical ecology of fungi.

    Science.gov (United States)

    Spiteller, Peter

    2015-07-01

    Fungi are widespread in nature and have conquered nearly every ecological niche. Fungi occur not only in terrestrial but also in freshwater and marine environments. Moreover, fungi are known as a rich source of secondary metabolites. Despite these facts, the ecological role of many of these metabolites is still unknown and the chemical ecology of fungi has not been investigated systematically so far. This review intends to present examples of the various chemical interactions of fungi with other fungi, plants, bacteria and animals and to give an overview of the current knowledge of fungal chemical ecology.

  13. CHEMICALS AND REPRODUCTIVE HEALTH

    Directory of Open Access Journals (Sweden)

    Omer Faruk TEKBAS

    2006-02-01

    Full Text Available However a lot of chemicals had been used in our daily life, we have enough knowledge about the effects of only for a small portion of them on reproductive health. Our knowledge had been arisen from epidemiologic and experimental studies. In order to protect ourselves from chemicals in the environment it should be concentrate on experimental studies and the results of them should be carefully studied during epidemiological researches. It would be tried to tell about the main chemicals which had been known as effective on reproductive health on the following review. [TAF Prev Med Bull 2006; 5(1.000: 50-59

  14. Elements of chemical thermodynamics

    CERN Document Server

    Nash, Leonard K

    2005-01-01

    This survey of purely thermal data in calculating the position of equilibrium in a chemical reaction highlights the physical content of thermodynamics, as distinct from purely mathematical aspects. 1970 edition.

  15. Chemical Physics Summer School

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-06-28

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

  16. Biotechnology for renewable chemicals

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  17. Chemical Engineering at NASA

    Science.gov (United States)

    Collins, Jacob

    2008-01-01

    This viewgraph presentation is a review of the career paths for chemicals engineer at NASA (specifically NASA Johnson Space Center.) The author uses his personal experience and history as an example of the possible career options.

  18. Legendary Chemical Aphrodisiacs.

    Science.gov (United States)

    Waddell, Thomas G.; And Others

    1980-01-01

    Presents a survey of the literature and a summary of information regarding aphrodisiacs. Chemical compounds are discussed as groups of plant natural products, animal natural products, and synthetic products. (CS)

  19. Chemical evolution and life

    Directory of Open Access Journals (Sweden)

    Malaterre Christophe

    2015-01-01

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

  20. Chemical agent recoveries

    Data.gov (United States)

    U.S. Environmental Protection Agency — Dataset shows the calculation of reported decontamination efficacies from the raw data (i.e., measured amount of chemical recovered from test coupons and positive...

  1. 219-S chemical compatibility

    Energy Technology Data Exchange (ETDEWEB)

    GOODWIN, L.D.

    1999-08-31

    This document consists of tables of the materials that make up the ''wetted'' parts of the 219-S waste handling facility and a combination of manufacturer lists of chemicals that are not recommended.

  2. Chemical Data Access Tool

    Data.gov (United States)

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

  3. Chemicals from coal

    Energy Technology Data Exchange (ETDEWEB)

    Harold A. Wittcoff; Bryan G. Reuben; Jeffrey S. Plotkin

    2004-12-01

    This chapter contains sections titled: Chemicals from Coke Oven Distillate; The Fischer-Tropsch Reaction; Coal Hydrogenation; Substitute Natural Gas (SNG); Synthesis Gas Technology; Calcium Carbide; Coal and the Environment; and Notes and References

  4. A bionics chemical synapse.

    Science.gov (United States)

    Thanapitak, Surachoke; Toumazou, Christofer

    2013-06-01

    Implementation of the current mode CMOS circuit for chemical synapses (AMPA and NMDA receptors) with dynamic change of glutamate as the neurotransmitter input is presented in this paper. Additionally, circuit realisation for receptor GABA(A) and GABA(B) with an electrical signal which symbolises γ-Aminobutyric Acid (GABA) perturbation is introduced. The chemical sensor for glutamate sensing is the modified ISFET with enzyme (glutamate oxidase) immobilisation. The measured results from these biomimetics chemical synapse circuits closely match with the simulation result from the mathematical model. The total power consumption of the whole chip (four chemical synapse circuits and all auxiliary circuits) is 168.3 μW. The total chip area is 3 mm(2) in 0.35-μm AMS CMOS technology.

  5. Countermeasures to Hazardous Chemicals,

    Science.gov (United States)

    1989-04-01

    of any effective community awareness and emergency response program is an informed public familiar with the operations of local chemical plants. Such a...protection systems. 2. Booklel, ’Protecting People and the Environment.’ - A concise booklet developed to familiarize the public with chemical operations and...Jefe, Seccion de Estudios y Planificacion 102. Civil Defense Administation c/Evaristo San Miguel, 8 Ministry of Interior Madrid-8 Ankara ESPANA

  6. Computational Systems Chemical Biology

    OpenAIRE

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

    2011-01-01

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

  7. Sawmill chemicals and carcinogenesis.

    OpenAIRE

    Huff, J

    2001-01-01

    Workers in wood industries are exposed to variable medleys of chemicals, both natural and synthetic. Additional exposures include fungi, bacteria, bark and wood dusts, solvents, paints, and various other wood coatings. These individual and conglomerate exposures have been associated with diverse occupational illnesses and hazards, including cancers. In this commentary, I summarize both experimental and epidemiologic carcinogenesis results for several chemicals used in the wood industry, as we...

  8. Chemical Ionization Mass Spectrometry.

    Science.gov (United States)

    1980-01-30

    mass spectrometer. Also discussed were Corporation, St. Louis , Mo. unique analytical applications of several negative ion chemical Synthesis of the...were purchsed from obtained at a probe temperature of 180-200 °C and displays Sigma Chemical Co.. St. Louis , Mo. Arginine hydrochloride (4) a M4...13) Rosenstock. H, M.: Drax . K.: Stener. B. W: Hernon J. T. J. Phys. Chem, Ref. Data 1977, 6, Supl. 1. 774-783,167 occur in the ratio of 10/ 1

  9. Environmental/chemical thesaurus

    Energy Technology Data Exchange (ETDEWEB)

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

    1978-06-01

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

  10. Computational systems chemical biology.

    Science.gov (United States)

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

    2011-01-01

    There is a critical need for improving the level of chemistry awareness in systems biology. The data and information related to modulation of genes and proteins by small molecules continue to accumulate at the same time as simulation tools in systems biology and whole body physiologically based pharmacokinetics (PBPK) continue to evolve. We called this emerging area at the interface between chemical biology and systems biology systems chemical biology (SCB) (Nat Chem Biol 3: 447-450, 2007).The overarching goal of computational SCB is to develop tools for integrated chemical-biological data acquisition, filtering and processing, by taking into account relevant information related to interactions between proteins and small molecules, possible metabolic transformations of small molecules, as well as associated information related to genes, networks, small molecules, and, where applicable, mutants and variants of those proteins. There is yet an unmet need to develop an integrated in silico pharmacology/systems biology continuum that embeds drug-target-clinical outcome (DTCO) triplets, a capability that is vital to the future of chemical biology, pharmacology, and systems biology. Through the development of the SCB approach, scientists will be able to start addressing, in an integrated simulation environment, questions that make the best use of our ever-growing chemical and biological data repositories at the system-wide level. This chapter reviews some of the major research concepts and describes key components that constitute the emerging area of computational systems chemical biology.

  11. The Chemical Revolution revisited.

    Science.gov (United States)

    Chang, Hasok

    2015-02-01

    I respond to the critical comments by Martin Kusch and Ursula Klein on my account of the Chemical Revolution. I comment along three different lines: descriptive, explanatory, and normative. (1) I agree with Klein that Lavoisier did not introduce drastic changes in chemical ontology, but maintain that there was methodological incommensurability in the Chemical Revolution; in response to Kusch's view, I maintain that Lavoisier's victory was slow and incomplete. (2) Admitting that there were many causes shaping the outcome of the Chemical Revolution, including the convenience of Lavoisier's theoretical scheme and various complicated social factors, I still think that the general rise of compositionism was an important factor. (3) I defend my normative pluralist view on the Chemical Revolution, denying Kusch's argument that chemists had overwhelmingly good reasons to trust Lavoisier and his allies over the phlogistonists. Overall, I agree with Kusch that it would be desirable to have a good descriptive-normative sociological account of the Chemical Revolution, but I also think that it should be an account that allows for divergence in individuals' and sub-communities' self-determination.

  12. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

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

  13. Current Chemical Risk Reduction Activities

    Science.gov (United States)

    EPA's existing chemicals programs address pollution prevention, risk assessment, hazard and exposure assessment and/or characterization, and risk management for chemicals substances in commercial use.

  14. Accessing and using chemical databases

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  15. Biological and Chemical Security

    Energy Technology Data Exchange (ETDEWEB)

    Fitch, P J

    2002-12-19

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

  16. Protein Chemical Shift Prediction

    CERN Document Server

    Larsen, Anders S

    2014-01-01

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

  17. Chemically Powered Nanomotors

    Science.gov (United States)

    Kapral, Raymond

    2007-03-01

    Molecular motors play important roles in transport in biological systems. These molecular machines are powered by chemical energy and operate in the regime of low Reynolds number hydrodynamics. Recently a class of simple inorganic molecular motors has been constructed and studied experimentally [1,2]. These motors are bimetallic rods, one end of which is chemically active. The talk will describe simple mesoscopic models for the motion of such nanomotors. The motor consists of two linked spheres, one of which catalyzes the conversion between two chemical species. The chemical species interact differently with the the two spheres in the dimer. The nano-dimer motor is solvated by a molecules treated at a mesoscopic level whose evolution is governed by multi-particle collision dynamics. The dynamics conserves mass, momentum and energy so that coupling between the nanomotor and the hydrodynamic modes of the solvent is treated correctly. The simulations allow one to explore the mechanisms of the chemically powered motion and the effects of fluctuations on the motor dynamics. [1] W. F. Paxton, et al., ``Catalytic Nanomotors: Autonomous Movement of Striped Nanorods,'' J. Am. Chem. Soc. (JACS), 126 (41), 13424 (2004). [2] S. Fournier-Bidoz, et al. ``Synthetic Self-Propelled Nanorotors,'' Chem. Commun., (4), 441 (2005).

  18. Nanotechnology for chemical engineers

    CERN Document Server

    Salaheldeen Elnashaie, Said; Hashemipour Rafsanjani, Hassan

    2015-01-01

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

  19. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

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

  20. Translated chemical reaction networks.

    Science.gov (United States)

    Johnston, Matthew D

    2014-05-01

    Many biochemical and industrial applications involve complicated networks of simultaneously occurring chemical reactions. Under the assumption of mass action kinetics, the dynamics of these chemical reaction networks are governed by systems of polynomial ordinary differential equations. The steady states of these mass action systems have been analyzed via a variety of techniques, including stoichiometric network analysis, deficiency theory, and algebraic techniques (e.g., Gröbner bases). In this paper, we present a novel method for characterizing the steady states of mass action systems. Our method explicitly links a network's capacity to permit a particular class of steady states, called toric steady states, to topological properties of a generalized network called a translated chemical reaction network. These networks share their reaction vectors with their source network but are permitted to have different complex stoichiometries and different network topologies. We apply the results to examples drawn from the biochemical literature.

  1. Precision Chemical Abundance Measurements

    DEFF Research Database (Denmark)

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

    2012-01-01

    This talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios. Our results indicate that the ob......This talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios. Our results indicate...... that the observed abundance dispersion exceeds the measurement uncertainties and that many pairs of elements show significant correlations when plotting [X1/H] vs. [X2/H]. Our tentative conclusions are that either NGC 6752 is not chemically homogeneous at the ~=0.03 dex level or the abundance variations...

  2. Chemical Inhibition of Autophagy

    DEFF Research Database (Denmark)

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

    2016-01-01

    Chinese hamster ovary (CHO) cells activate and undergo apoptosis and autophagy for various environmental stresses. Unlike apoptosis, studies on increasing the production of therapeutic proteins in CHO cells by targeting the autophagy pathway are limited. In order to identify the effects of chemical...... autophagy inhibitors on the specific productivity (qp), nine chemical inhibitors that had been reported to target three different phases of autophagy (metformin, dorsomorphin, resveratrol, and SP600125 against initiation and nucleation; 3-MA, wortmannin, and LY294002 against elongation, and chloroquine...... and bafilomycin A1 against autophagosome fusion) were used to treat three recombinant CHO (rCHO) cell lines: the Fc-fusion protein-producing DG44 (DG44-Fc) and DUKX-B11 (DUKX-Fc) and antibody-producing DG44 (DG44-Ab) cell lines. Among the nine chemical inhibitors tested, 3-MA, dorsomorphin, and SP600125...

  3. Applied chemical engineering thermodynamics

    CERN Document Server

    Tassios, Dimitrios P

    1993-01-01

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

  4. Chemical inhomogeneities and pulsation

    CERN Document Server

    Turcotte, S

    2001-01-01

    Major improvements in models of chemically peculiar stars have been achieved in the past few years. With these new models it has been possible to test quantitatively some of the processes involved in the formation of abundance anomalies and their effect on stellar structure. The models of metallic A (Am) stars have shown that a much deeper mixing has to be present to account for observed abundance anomalies. This has implications on their variability, which these models also reproduce qualitatively. These models also have implications for other chemically inhomogeneous stars such as HgMn B stars which are not known to be variable and lambda Bootis stars which can be. The study of the variability of chemically inhomogeneous stars can provide unique information on the dynamic processes occurring in many types of stars in addition to modeling of the evolution of their surface composition.

  5. Chemical Kinetics Database

    Science.gov (United States)

    SRD 17 NIST Chemical Kinetics Database (Web, free access)   The NIST Chemical Kinetics Database includes essentially all reported kinetics results for thermal gas-phase chemical reactions. The database is designed to be searched for kinetics data based on the specific reactants involved, for reactions resulting in specified products, for all the reactions of a particular species, or for various combinations of these. In addition, the bibliography can be searched by author name or combination of names. The database contains in excess of 38,000 separate reaction records for over 11,700 distinct reactant pairs. These data have been abstracted from over 12,000 papers with literature coverage through early 2000.

  6. Chemicals in material cycles

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  7. Endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Mandrup, Karen

    BACKGROUND: Endocrine disrupting chemicals (EDCs) may contribute to reproductive changes in boys in the Western world, however, less is known about influence of EDCs in women. The incidence of precocious breast development is increasing in USA and Europe and mammary gland development has been...... suggested as particularly sensitive to endocrine disruption. Mammary gland examination in toxicological studies may be useful for improving knowledge on possible influences of EDCs on human mammary glands and also be useful for detection of endocrine disrupting effects of chemicals as part of safety testing...... and genistein, a mixture of phytoestrogens, and a mixture of environmentally relevant estrogenic EDCs of various origins. Moreover, mixtures of antiandrogenic chemicals were investigated. These include a mixture of pesticides and a mixture of environmentally relevant anti-androgenic EDCs of various origins...

  8. Chemical profiling of chemical warfare agents for forensic purposes

    NARCIS (Netherlands)

    Noort, D.; Reuver, L.P.J. de; Fidder, A.; Tromp, M.; Verschraagen, M.

    2010-01-01

    A program has been initiated towards the chemical profiling of chemical warfare agents, in order to support forensic investigations towards synthesis routes, production sites and suspect chemical suppliers. Within the first stage of the project various chemical warfare agents (VX, sulfur mustard, sa

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

    Energy Technology Data Exchange (ETDEWEB)

    Harwood, B.J.

    1993-01-01

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

  10. Principles of chemical kinetics

    CERN Document Server

    House, James E

    2007-01-01

    James House's revised Principles of Chemical Kinetics provides a clear and logical description of chemical kinetics in a manner unlike any other book of its kind. Clearly written with detailed derivations, the text allows students to move rapidly from theoretical concepts of rates of reaction to concrete applications. Unlike other texts, House presents a balanced treatment of kinetic reactions in gas, solution, and solid states. The entire text has been revised and includes many new sections and an additional chapter on applications of kinetics. The topics covered include quantitative rela

  11. Chemical allergy in humans

    DEFF Research Database (Denmark)

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

    2014-01-01

    functional sub-populations of CD4(+) and CD8(+) T-lymphocytes. Evidence for a similar association of chemical allergy in humans with discrete T-lymphocyte populations is, however, limited. It is of some interest, therefore, that two recent articles from different teams of investigators have shed new light...... on the role of polarized T-lymphocyte responses in the development of allergic contact dermatitis and occupational asthma in humans. The implications for understanding of chemical allergy in humans are explored in this Commentary....

  12. Chemical space and biology.

    Science.gov (United States)

    Dobson, Christopher M

    2004-12-16

    Chemical space--which encompasses all possible small organic molecules, including those present in biological systems--is vast. So vast, in fact, that so far only a tiny fraction of it has been explored. Nevertheless, these explorations have greatly enhanced our understanding of biology, and have led to the development of many of today's drugs. The discovery of new bioactive molecules, facilitated by a deeper understanding of the nature of the regions of chemical space that are relevant to biology, will advance our knowledge of biological processes and lead to new strategies to treat disease.

  13. CHEMICAL TOXICITY OF URANIUM

    Directory of Open Access Journals (Sweden)

    Sermin Cam

    2007-06-01

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

  14. Magnetic chemically peculiar stars

    CERN Document Server

    Schöller, Markus

    2015-01-01

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

  15. Environmental Chemicals in Breast Milk

    Science.gov (United States)

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

  16. Chemical hygiene plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

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

  17. Chemical Product Design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    2004-01-01

    This paper highlights for a class of chemical products, the design process, their design with respect to the important issues, the need for appropriate tools and finally, lists some of the challenges and opportunities for the process systems engineering (PSE)/computer-aided process engineering...

  18. Chemical and Petrochemical Sector

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

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

  19. The renewable chemicals industry

    DEFF Research Database (Denmark)

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

    2008-01-01

    The possibilities for establishing a renewable chemicals industry featuring renewable resources as the dominant feedstock rather than fossil resources are discussed in this Concept. Such use of biomass can potentially be interesting from both an economical and ecological perspective. Simple and e...

  20. Chemically Reacting Turbulent Flow.

    Science.gov (United States)

    1987-04-14

    two stages of gen I tubes equipped with P-47 phosphor screens The detector chosen for the camera was a Reticon RL128S* line detectoI- .,hich consists...the Stud’, of Turbulent Mixing," William M. Pitts, Nuclear Engineering Seminar of the Department of Chemical and Nuclear Engineering, University of

  1. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

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

  2. Chemical Safety – Introduction

    CERN Multimedia

    DG Unit

    2009-01-01

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

  3. Multiple Chemical Sensitivity

    DEFF Research Database (Denmark)

    Junge, Anne Gram

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

  4. Hydroxyl Radical Chemical Laser

    Science.gov (United States)

    1977-11-01

    Stone (I) 1 Atlantic Research Corporation, Alexandria, VA (Robert Naismith ) I Battelle Columbus laboratories, Columbus, OH (Fred Tietzel) 1...Corporation, Santa Monica, CA (Dr. Claude R. Culp) 1 Thiokol Chemical Corporation, Wasatch Division, Brigham City, UT ( James E. Hansen) 4 United

  5. Chemical Aspects of Dentistry.

    Science.gov (United States)

    Helfman, Murry

    1982-01-01

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

  6. Chemical defences against herbivores

    DEFF Research Database (Denmark)

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

    2012-01-01

    of these theories, concluding with new chemical approaches to tackle the questions and suggestions for future research directions. It explains that aquatic primary producers are a taxonomically and functionally diverse group of organisms that includes macroalgae, microalgae, and vascular plants. It also states...

  7. Plant Diseases & Chemicals

    OpenAIRE

    Thompson, Sherm

    2008-01-01

    This course discusses the use of chemicals for plant disease control. Specifically, pesticides that can be used both in commercial or home/yard sitautions. This course also teaches how to determine plant diseases that may have caused a plant to die.

  8. Chemicals of Common bitercress

    Directory of Open Access Journals (Sweden)

    M. Marenich

    2012-12-01

    Full Text Available Article is devoted to the study of the chemical composition of Common bitter cress (Barbarea vulgaris R. Br.. Shows indicators of good quality, optimal parameters extraction, trace element composition, amino acid composition, content of biologically active substances and volatile of raw material.

  9. Power plant chemical technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

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

  10. Bulk chemicals from biomass

    NARCIS (Netherlands)

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

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Lei Chen

    Full Text Available Lung cancer causes over one million deaths every year worldwide. However, prevention and treatment methods for this serious disease are limited. The identification of new chemicals related to lung cancer may aid in disease prevention and the design of more effective treatments. This study employed a weighted network, constructed using chemical-chemical interaction information, to identify new chemicals related to two types of lung cancer: non-small lung cancer and small-cell lung cancer. Then, a randomization test as well as chemical-chemical interaction and chemical structure information were utilized to make further selections. A final analysis of these new chemicals in the context of the current literature indicates that several chemicals are strongly linked to lung cancer.

  12. Chemical Sensing with Nanowires

    Science.gov (United States)

    Penner, Reginald M.

    2012-07-01

    Transformational advances in the performance of nanowire-based chemical sensors and biosensors have been achieved over the past two to three years. These advances have arisen from a better understanding of the mechanisms of transduction operating in these devices, innovations in nanowire fabrication, and improved methods for incorporating receptors into or onto nanowires. Nanowire-based biosensors have detected DNA in undiluted physiological saline. For silicon nanowire nucleic acid sensors, higher sensitivities have been obtained by eliminating the passivating oxide layer on the nanowire surface and by substituting uncharged protein nucleic acids for DNA as the capture strands. Biosensors for peptide and protein cancer markers, based on both semiconductor nanowires and nanowires of conductive polymers, have detected these targets at physiologically relevant concentrations in both blood plasma and whole blood. Nanowire chemical sensors have also detected several gases at the parts-per-million level. This review discusses these and other recent advances, concentrating on work published in the past three years.

  13. Environmental and chemical carcinogenesis.

    Science.gov (United States)

    Wogan, Gerald N; Hecht, Stephen S; Felton, James S; Conney, Allan H; Loeb, Lawrence A

    2004-12-01

    People are continuously exposed exogenously to varying amounts of chemicals that have been shown to have carcinogenic or mutagenic properties in experimental systems. Exposure can occur exogenously when these agents are present in food, air or water, and also endogenously when they are products of metabolism or pathophysiologic states such as inflammation. It has been estimated that exposure to environmental chemical carcinogens may contribute significantly to the causation of a sizable fraction, perhaps a majority, of human cancers, when exposures are related to "life-style" factors such as diet, tobacco use, etc. This chapter summarizes several aspects of environmental chemical carcinogenesis that have been extensively studied and illustrates the power of mechanistic investigation combined with molecular epidemiologic approaches in establishing causative linkages between environmental exposures and increased cancer risks. A causative relationship between exposure to aflatoxin, a strongly carcinogenic mold-produced contaminant of dietary staples in Asia and Africa, and elevated risk for primary liver cancer has been demonstrated through the application of well-validated biomarkers in molecular epidemiology. These studies have also identified a striking synergistic interaction between aflatoxin and hepatitis B virus infection in elevating liver cancer risk. Use of tobacco products provides a clear example of cancer causation by a life-style factor involving carcinogen exposure. Tobacco carcinogens and their DNA adducts are central to cancer induction by tobacco products, and the contribution of specific tobacco carcinogens (e.g. PAH and NNK) to tobacco-induced lung cancer, can be evaluated by a weight of evidence approach. Factors considered include presence in tobacco products, carcinogenicity in laboratory animals, human uptake, metabolism and adduct formation, possible role in causing molecular changes in oncogenes or suppressor genes, and other relevant data

  14. Chemical Synthesis of Glycosaminoglycans.

    Science.gov (United States)

    Mende, Marco; Bednarek, Christin; Wawryszyn, Mirella; Sauter, Paul; Biskup, Moritz B; Schepers, Ute; Bräse, Stefan

    2016-07-27

    Glycosaminoglycans (GAGs) as one major part of the glycocalyx are involved in many essential biological cell processes, as well as in many courses of diseases. Because of the potential therapeutic application of GAG polymers, fragments, and also derivatives toward different diseases (e.g., heparin derivatives against Alzheimer's disease), there is a continual growing demand for new chemical syntheses, which suffice the high claim to stereoselectivity and chemoselectivity. This Review summarizes the progress of chemical syntheses of GAGs over the last 10 years. For each class of the glycosaminoglycans-hyaluronan (HA), heparan sulfate/heparin (HS/HP), chondroitin/dermatan sulfate (CS/DS), and keratan sulfate (KS)-mainly novel glycosylation strategies, elongation sequences, and protecting group patterns are discussed, but also (semi)automated syntheses, enzymatic approaches, and functionalizations of synthesized or isolated GAGs are considered.

  15. Chemical Engineering in Space

    Science.gov (United States)

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

    2001-01-01

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

  16. Chemical aerosol Raman detector

    Science.gov (United States)

    Aggarwal, R. L.; Farrar, L. W.; Di Cecca, S.; Amin, M.; Perkins, B. G.; Clark, M. L.; Jeys, T. H.; Sickenberger, D. W.; D'Amico, F. M.; Emmons, E. D.; Christesen, S. D.; Kreis, R. J.; Kilper, G. K.

    2017-03-01

    A sensitive chemical aerosol Raman detector (CARD) has been developed for the trace detection and identification of chemical particles in the ambient atmosphere. CARD includes an improved aerosol concentrator with a concentration factor of about 40 and a CCD camera for improved detection sensitivity. Aerosolized isovanillin, which is relatively safe, has been used to characterize the performance of the CARD. The limit of detection (SNR = 10) for isovanillin in 15 s has been determined to be 1.6 pg/cm3, which corresponds to 6.3 × 109 molecules/cm3 or 0.26 ppb. While less sensitive, CARD can also detect gases. This paper provides a more detailed description of the CARD hardware and detection algorithm than has previously been published.

  17. Chemical genetics and regeneration.

    Science.gov (United States)

    Sengupta, Sumitra; Zhang, Liyun; Mumm, Jeff S

    2015-01-01

    Regeneration involves interactions between multiple signaling pathways acting in a spatially and temporally complex manner. As signaling pathways are highly conserved, understanding how regeneration is controlled in animal models exhibiting robust regenerative capacities should aid efforts to stimulate repair in humans. One way to discover molecular regulators of regeneration is to alter gene/protein function and quantify effect(s) on the regenerative process: dedifferentiation/reprograming, stem/progenitor proliferation, migration/remodeling, progenitor cell differentiation and resolution. A powerful approach for applying this strategy to regenerative biology is chemical genetics, the use of small-molecule modulators of specific targets or signaling pathways. Here, we review advances that have been made using chemical genetics for hypothesis-focused and discovery-driven studies aimed at furthering understanding of how regeneration is controlled.

  18. COOEE bitumen: chemical aging

    CERN Document Server

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

    2013-01-01

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

  19. Autocatalytic chemical smoke rings

    CERN Document Server

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

    2005-01-01

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

  20. Biocatalysis for Biobased Chemicals

    Directory of Open Access Journals (Sweden)

    Rubén de Regil

    2013-10-01

    Full Text Available The design and development of greener processes that are safe and friendly is an irreversible trend that is driven by sustainable and economic issues. The use of Biocatalysis as part of a manufacturing process fits well in this trend as enzymes are themselves biodegradable, require mild conditions to work and are highly specific and well suited to carry out complex reactions in a simple way. The growth of computational capabilities in the last decades has allowed Biocatalysis to develop sophisticated tools to understand better enzymatic phenomena and to have the power to control not only process conditions but also the enzyme’s own nature. Nowadays, Biocatalysis is behind some important products in the pharmaceutical, cosmetic, food and bulk chemicals industry. In this review we want to present some of the most representative examples of industrial chemicals produced in vitro through enzymatic catalysis.

  1. Interactive Chemical Reactivity Exploration

    CERN Document Server

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

    2014-01-01

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

  2. Chemical Decontaminant Testing

    Science.gov (United States)

    2014-10-20

    any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display...Some test methods for efficacy require the use of CWAs and decontaminants. 15. SUBJECT TERMS decontamination; chemical warfare agent; CWA...contaminant in samples from contact samplers , coupons, rinsate, or other samples. MS, GC or LC, FID, FPD, or equivalents. ±15 percent of the mass of

  3. Chemical transport reactions

    CERN Document Server

    Schäfer, Harald

    2013-01-01

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

  4. Chemical constituents of Asparagus

    Directory of Open Access Journals (Sweden)

    J S Negi

    2010-01-01

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

  5. Control of chemical chaos

    Institute of Scientific and Technical Information of China (English)

    李卫东; 钱积新

    2002-01-01

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

  6. Chemical Reactions at Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Michael Henderson and Nancy Ryan Gray

    2010-04-14

    Chemical reactions at surfaces underlie some of the most important processes of today, including catalysis, energy conversion, microelectronics, human health and the environment. Understanding surface chemical reactions at a fundamental level is at the core of the field of surface science. The Gordon Research Conference on Chemical Reactions at Surfaces is one of the premiere meetings in the field. The program this year will cover a broad range of topics, including heterogeneous catalysis and surface chemistry, surfaces in environmental chemistry and energy conversion, reactions at the liquid-solid and liquid-gas interface, electronic materials growth and surface modification, biological interfaces, and electrons and photons at surfaces. An exciting program is planned, with contributions from outstanding speakers and discussion leaders from the international scientific community. The conference provides a dynamic environment with ample time for discussion and interaction. Attendees are encouraged to present posters; the poster sessions are historically well attended and stimulate additional discussions. The conference provides an excellent opportunity for junior researchers (e.g. graduate students or postdocs) to present their work and interact with established leaders in the field.

  7. Metabolomics in chemical ecology.

    Science.gov (United States)

    Kuhlisch, Constanze; Pohnert, Georg

    2015-07-01

    Chemical ecology elucidates the nature and role of natural products as mediators of organismal interactions. The emerging techniques that can be summarized under the concept of metabolomics provide new opportunities to study such environmentally relevant signaling molecules. Especially comparative tools in metabolomics enable the identification of compounds that are regulated during interaction situations and that might play a role as e.g. pheromones, allelochemicals or in induced and activated defenses. This approach helps overcoming limitations of traditional bioassay-guided structure elucidation approaches. But the power of metabolomics is not limited to the comparison of metabolic profiles of interacting partners. Especially the link to other -omics techniques helps to unravel not only the compounds in question but the entire biosynthetic and genetic re-wiring, required for an ecological response. This review comprehensively highlights successful applications of metabolomics in chemical ecology and discusses existing limitations of these novel techniques. It focuses on recent developments in comparative metabolomics and discusses the use of metabolomics in the systems biology of organismal interactions. It also outlines the potential of large metabolomics initiatives for model organisms in the field of chemical ecology.

  8. Tier II Chemical Storage Facilities

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Facilities that store hazardous chemicals above certain quantities must submit an annual emergency and hazardous chemical inventory on a Tier II form. This is a...

  9. Fiber Bragg distributed chemical sensor

    NARCIS (Netherlands)

    Boersma, A.; Cheng, L.K.; Jansen, T.H.

    2010-01-01

    A distributed chemical sensor is developed by coating multiple Bragg gratings in a fibre with chemical selective responsive coatings. The optical response of the coated grating is optimised and the recoat process is very reproducible.

  10. Stochastic processes in chemical physics

    CERN Document Server

    Shuler, K E

    2009-01-01

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

  11. Galactic Chemical Evolution

    CERN Document Server

    Mollá, M; da Costa, R; Gibson, B K; Díaz, A I

    2016-01-01

    We analyze the evolution of oxygen abundance radial gradients resulting from our chemical evolution models calculated with different prescriptions for the star formation rate (SFR) and for the gas infall rate, in order to assess their respective roles in shaping gradients. We also compare with cosmological simulations and confront all with recent observational datasets, in particular with abundances inferred from planetary nebulae. We demonstrate the critical importance in isolating the specific radial range over which a gradient is measured, in order for their temporal evolution to be useful indicators of disk growth with redshift.

  12. Chemical kinetics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Laboratory, CA (United States)

    1993-12-01

    This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

  13. Modern Chemical Technology, Volume 5.

    Science.gov (United States)

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

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

  14. Green chemistry for chemical synthesis

    OpenAIRE

    Li, Chao-Jun; Trost, Barry M.

    2008-01-01

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

  15. Green chemistry for chemical synthesis

    Science.gov (United States)

    Li, Chao-Jun; Trost, Barry M.

    2008-01-01

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

  16. Mass Transfer with Chemical Reaction.

    Science.gov (United States)

    DeCoursey, W. J.

    1987-01-01

    Describes the organization of a graduate course dealing with mass transfer, particularly as it relates to chemical reactions. Discusses the course outline, including mathematics models of mass transfer, enhancement of mass transfer rates by homogeneous chemical reaction, and gas-liquid systems with chemical reaction. (TW)

  17. Fiber Bragg distributed chemical sensor

    NARCIS (Netherlands)

    Boersma, A.; Saalmink, M.; Lucassen, T.; Wiegersma, S.; Jansen, T.H.; Jansen, R.; Cheng, L.K.

    2011-01-01

    A distributed chemical sensor is developed by coating multiple Bragg gratings in a single glass fiber with chemical responsive coatings. The composition of the coating is tuned to the target chemicals to be measured and the optical response of the coated grating is optimized by changing the coating

  18. Identification of Chemical Toxicity Using Ontology Information of Chemicals

    Directory of Open Access Journals (Sweden)

    Zhanpeng Jiang

    2015-01-01

    Full Text Available With the advance of the combinatorial chemistry, a large number of synthetic compounds have surged. However, we have limited knowledge about them. On the other hand, the speed of designing new drugs is very slow. One of the key causes is the unacceptable toxicities of chemicals. If one can correctly identify the toxicity of chemicals, the unsuitable chemicals can be discarded in early stage, thereby accelerating the study of new drugs and reducing the R&D costs. In this study, a new prediction method was built for identification of chemical toxicities, which was based on ontology information of chemicals. By comparing to a previous method, our method is quite effective. We hope that the proposed method may give new insights to study chemical toxicity and other attributes of chemicals.

  19. Frontiers in Chemical Physics

    Energy Technology Data Exchange (ETDEWEB)

    Bowlan, Pamela Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-02

    These are slides dealing with frontiers in chemical physics. The following topics are covered: Time resolving chemistry with ultrashort pulses in the 0.1-40 THz spectral range; Example: Mid-infrared absorption spectrum of the intermediate state CH2OO; Tracking reaction dynamics through changes in the spectra; Single-shot measurement of the mid-IR absorption dynamics; Applying 2D coherent mid-IR spectroscopy to learn more about transition states; Time resolving chemical reactions at a catalysis using mid-IR and THz pulses; Studying topological insulators requires a surface sensitive probe; Nonlinear phonon dynamics in Bi2Se3; THz-pump, SHG-probe as a surface sensitive coherent 2D spectroscopy; Nanometer and femtosecond spatiotemporal resolution mid-IR spectroscopy; Coherent two-dimensional THz/mid-IR spectroscopy with 10nm spatial resolution; Pervoskite oxides as catalysts; Functionalized graphene for catalysis; Single-shot spatiotemporal measurements; Spatiotemporal pulse measurement; Intense, broad-band THz/mid-IR generation with organic crystals.

  20. Wearable Optical Chemical Sensors

    Science.gov (United States)

    Lobnik, Aleksandra

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

  1. Pressure Controlled Chemical Gardens.

    Science.gov (United States)

    Bentley, Megan R; Batista, Bruno C; Steinbock, Oliver

    2016-06-30

    The dissolution of metal salts in silicate solution can result in the growth of hollow precipitate tubes. These "chemical gardens" are a model of self-organization far from the equilibrium and create permanent macroscopic structures. The reproducibility of the growth process is greatly improved if the solid salt seed is replaced by a salt solution that is steadily injected by a pump; however, this modification of the original experiment eliminates the membrane-based osmotic pump at the base of conventional chemical gardens and does not allow for analyses in terms of the involved pressure. Here we describe a new experimental method that delivers the salt solution according to a controlled hydrostatic pressure. In one form of the experiment, this pressure slowly decreases as zinc sulfate solution flows into the silicate-containing reaction vessel, whereas a second version holds the respective solution heights constant. In addition to three known growth regimes (jetting, popping, budding), we observe single tubes that fill the vessel in a horizontally undulating but vertically layered fashion (crowding). The resulting, dried product has a cylindrical shape, very low density, and one continuous connection from top to bottom. We also present phase diagrams of these growth modes and show that the flow characteristics of our experiments follow a reaction-independent Hagen-Poiseuille equation.

  2. Chemical simulation of greywater.

    Science.gov (United States)

    Abed, Suhail Najem; Scholz, Miklas

    2016-01-01

    Sustainable water resources management attracts considerable attention in today's world. Recycling and reuse of both wastewater and greywater are becoming more attractive. The strategy is to protect ecosystem services by balancing the withdrawal of water and the disposal of wastewater. In the present study, a timely and novel synthetic greywater composition has been proposed with respect to the composition of heavy metals, nutrients and organic matter. The change in water quality of the synthetic greywater due to increasing storage time was monitored to evaluate the stability of the proposed chemical formula. The new greywater is prepared artificially using analytical-grade chemicals to simulate either low (LC) or high (HC) pollutant concentrations. The characteristics of the synthetic greywater were tested (just before starting the experiment, after two days and a week of storage under real weather conditions) and compared to those reported for real greywater. Test results for both synthetic greywater types showed great similarities with the physiochemical properties of published findings concerning real greywater. Furthermore, the synthetic greywater is relatively stable in terms of its characteristics for different storage periods. However, there was a significant (p greywater after two days of storage with reductions of 62% and 55%, respectively. A significant (p greywater after seven days of storage.

  3. Remanufacturing strategy for chemical equipment

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  4. Chemical face peels.

    Science.gov (United States)

    Matarasso, S L; Glogau, R G

    1991-01-01

    Application of caustic chemicals to improve cosmesis and reverse actinic damage has been used for centuries. Although still not an exact science, it was not until the latter part of this century that peeling became more systematized. The indications, patient selection, armamentarium, histology, comprehension of the mechanisms of action, and safety parameters of peels have only recently become more extensively defined. Phenol, when used in the Baker's formula, provides the most dramatic results but also holds the most potential for systemic complications. Ideally suited for fair-skinned women, a phenol peel can provide substantial improvement in rhytidosis and actinic damage. Although the results of medium-depth peels approach those of Baker's peels, they are not quite as profound. Use of TCA and the medium-depth peels has filled an important gap between deep and superficial peels, however. Also ideal for light complexions, this category of peels lightens pigmentary problems and improves rhytides with minimal potential for systemic toxicity; however, local complications, including scarring and pigmentary anomalies, should not be underestimated. [table: see text] Superficial peels do not effectively eradicate the ravages of time and sun, but when done repetitively, they do improve pigmentary irregularities and may improve some minor surface changes and thus impart a fresher appearance to facial skin. Although pigmentary changes can occur, superficial peels are relatively safe, and maximal results can be achieved with serial applications. Peels have been categorized by patient indications and the corresponding depth of peeling required for improvement (Table 4). The depth is determined in turn by a host of factors (Table 5). Neither the classification scheme nor the peel process should be viewed dogmatically. Patients will often benefit from the concurrent use of different skin preparations and wounding agents. Localized gradations can be achieved not only with

  5. Chemical Dependence and Personality

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Sancineto da Silva Nunes

    2009-01-01

    Full Text Available This study investigated the relationships between chemical dependency and personalitystructure in a Brazilian sample. Participants were college students (n=35 and patients of a drug recovery center (n= 48. Two personality scales based on the Big-5 Model were used to measure Extraversion and Agreeableness. A semi-structured interview was used to identify events in the patients' life histories that might support specific classifications. Participants' scores were also compared to Brazilian normative samples. The results showed significant differences between clinical and non-clinical groups in Agreeableness, but not in Extraversion. Logistic regression analyses were conducted using scales and interview aspects for predicting group membership. The model showed 92.1% general predictive power. Results pointed to the advantage of using both interview and objective techniques to assess individuals with antisocial personality symptoms.

  6. Chemically deposited tin sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Akkari, A., E-mail: anis.akkari@ies.univ-montp2.f [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences de Tunis El Manar, Tunisie 2092 (Tunisia); Institut d' Electronique du Sud, Unite Mixte de Recherche 5214 UM2-CNRS (ST2i), Universite Montpellier 2, Place Eugene Bataillon, CC 082, 34095 Montpellier Cedex 5 (France); Guasch, C. [Institut d' Electronique du Sud, Unite Mixte de Recherche 5214 UM2-CNRS (ST2i), Universite Montpellier 2, Place Eugene Bataillon, CC 082, 34095 Montpellier Cedex 5 (France); Kamoun-Turki, N. [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences de Tunis El Manar, Tunisie 2092 (Tunisia)

    2010-02-04

    SnS thin films were deposited on glass substrates after multi-deposition runs by chemical bath deposition from aqueous solution containing 30 ml triethanolamine (TEA) (C{sub 6}H{sub 15}NO{sub 3}) (50%), 10 ml thioacetamide (CH{sub 3}CSNH{sub 2}), 8 ml ammonia (NH{sub 3}) solution and 10 ml of Sn{sup 2+}(0.1 M). These films were characterised with X-ray diffraction (XRD), with scanning electron microscopy, and with spectrophotometric measurements. The obtained thin films exhibit the zinc blend structure, the crystallinity seems to be improved as the film thickness increases and the band gap energy is found to be about 1.76 eV for film prepared after six depositions runs.

  7. On Network Coded Filesystem Shim: Over-the-top Multipath Multi-Source Made Easy

    DEFF Research Database (Denmark)

    Sørensen, Chres Wiant; Roetter, Daniel Enrique Lucani; Médard, Muriel

    2017-01-01

    benefits to any application in a computer. However, incorporating new protocols to the Internet is a challenging and slow process. Second, deploying coding at the application layer, which forces each application to implement network coding. This paper proposes an alternative approach through the use...

  8. Chemical properties of mendelevium

    Energy Technology Data Exchange (ETDEWEB)

    Hulet, E.K.

    1980-11-01

    Even with the most intense ion beams and the largest available quantities of target isotope, about 10/sup 6/ atoms at a time is all the Md that can be produced for chemical studies. This lack of sufficient sample size coupled with the very short lifetimes of the few atoms produced has severely restricted the gathering and the broadness of our knowledge concerning the properties of Md and the heavier elements. To illustrate, the literature contains a mere eleven references to the chemical studies of Md, and none of these deal with bulk properties associated with the element bound in solid phases. Some of these findings are: Md was found to be more volatile than other actinide metals which lead to the belief that it is divalent in the metallic state; separation of Md from the other actinides can be accomplished either by reduction of Md/sup 3 +/ to the divalent state or by chromatographic separations with Md remaining in the tripositive state; extraction of Md/sup 2 +/ with bis(2-ethylhexyl)phosphoric acid is much poorer than the extraction of the neighboring tripositive actinides; attempts to oxidize Md/sup 3 +/ with sodium bismuthate failed to show any evidence for Md/sup 4 +/; reduction potential of Md/sup 3 +/ was found to be close to -0.1 volt; Md/sup 3 +/ can be reduced to Md(Hg) by sodium amalgams and by electrolysis; the electrochemical behavior of Md is very similar to that of Fm and can be summarized in the equation, Md/sup 2 +/ + 2e/sup -/ = Md(Hg) and E/sup 0/ = -1.50 V.; and Md cannot be reduced to a monovalent ion with Sm/sup 2 +/.

  9. Gas phase chemical detection with an integrated chemical analysis system

    Energy Technology Data Exchange (ETDEWEB)

    CASALNUOVO,STEPHEN A.; FRYE-MASON,GREGORY CHARLES; KOTTENSTETTE,RICHARD; HELLER,EDWIN J.; MATZKE,CAROLYN M.; LEWIS,PATRICK R.; MANGINELL,RONALD P.; BACA,ALBERT G.; HIETALA,VINCENT M.

    2000-04-12

    Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample preconcentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is described.

  10. Errors in Chemical Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Artur Dybko

    2001-06-01

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

  11. Perfect Actions with Chemical Potential

    CERN Document Server

    Bietenholz, W

    1998-01-01

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

  12. Fundamentals of chemical reaction engineering

    CERN Document Server

    Davis, Mark E

    2012-01-01

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

  13. A Chemical Technology Program Partnership

    Science.gov (United States)

    Hicks, Gary

    1998-01-01

    Brazosport College would be the first to admit that they owe the success of their Chemical Technology Program to the partnership that was developed between the college and the surrounding chemical industry. The college is a two-year institution located near the Texas Gulf Coast with more than twelve chemical companies in the immediate area. Dow Chemical is the largest, employing more than 5,000. Currently, the Science Department at Brazosport College offers associate of science degrees in biology, chemistry, and physics, and associate of applied science degrees in chemical technology and instrumentation technology to meet the needs of these industries. In addition, many students enroll in classes to prepare for specific occupations or to build their skills for employment. This may only require the student to take a few courses. The current Chemical Technology Program addresses skills needed for both laboratory and process technician jobs in the chemical industry. An Associate of Applied Science Degree in Chemical Technology is offered with either a laboratory or a process option. These programs were developed with input from the chemical industry, and the college trains all new process employees for BASF and Dow. Additionally, the college does customized flexible-entry training in process operations and laboratory analysis for these and several other companies.

  14. Chemical substructure analysis in toxicology

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-12-31

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

  15. Chemical Physics Electrons and Excitations

    CERN Document Server

    Larsson, Sven

    2012-01-01

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

  16. Chemical Stockpile Disposal Program

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-10-01

    As part of the Chemical Stockpile Disposal Program mandated by Public Law 99--145 (Department of Defense Authorization Act), an independent review is presented of the US Army Phase I environmental report for the disposal program at the Pine Bluff Arsenal (PBA) in Arkansas. The Phase I report addressed new and additional concerns not incorporated in the final programmatic environmental impact statement (FPEIS). Those concerns were addressed by examining site-specific data for the PBA and by recommending the scope and content of a more detailed site- specific study. This dependent review evaluates whether the new site-specific data presented in the Phase I report would alter the decision in favor of on-site disposal that was reached in the FPEIS, and whether the recommendations for the scope and content of the site-specific study are adequate. Based on the methods and assumptions presented in the FPEIS, the inclusion of more detailed site-specific data in the Phase I report does not change the decision reached in the FPEIS (which favored on-site disposal at PBA). It is recommended that alternative assumptions about meteorological conditions be considered and that site-specific data on water, ecological, socioeconomic, and cultural resources, and emergency planning and preparedness be considered explicitly in the site-specific EIS decision-making process. 13 refs., 1 fig.

  17. Chemical Stockpile Disposal Program

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-10-01

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

  18. Chemical communication in bacteria

    Science.gov (United States)

    Suravajhala, Srinivasa Sandeep; Saini, Deepak; Nott, Prabhu

    Luminescence in Vibrio fischeri is a model for quorum-sensing-gene-regulation in bacteria. We study luminescence response of V. fischeri to both internal and external cues at the single cell and population level. Experiments with ES114, a wild-type strain, and ainS mutant show that luminescence induction in cultures is not always proportional to cell-density and there is always a basal level of luminescence. At any given concentration of the exogenously added signals, C6-HSL and C8-HSL, luminescence per cell reaches a maximum during the exponential phase and decreases thereafter. We hypothesize that (1) C6-HSL production and LuxR activity are not proportional to cell-density, and (2) there is a shift in equilibrium from C6-HSL to C8-HSL during the later stages of growth of the culture. RT-PCR analysis of luxI and luxR shows that the expression of these genes is maximum corresponding to the highest level of luminescence. The shift in equilibrium is shown by studying competitive binding of C6-HSL and C8-HSL to LuxR. We argue that luminescence is a unicellular behaviour, and an intensive property like per cell luminescence is more important than gross luminescence of the population in understanding response of bacteria to chemical signalling. Funding from the Department of Science and Technology, India is acknowledged.

  19. Chemical mixtures: considering the evolution of toxicology and chemical assessment.

    Science.gov (United States)

    Monosson, Emily

    2005-04-01

    The assessment of chemical mixtures is a complex topic for toxicologists, regulators, and the public. In this article the linkage between the science of toxicology and the needs of governmental regulatory agencies in the United States is explored through an overview of environmental regulations enacted over the past century and a brief history of modern toxicology. One of the goals of this overview is to encourage both regulators and scientists to consider the benefits and limitations of this science-regulatory relationship as they tackle existing issues such as chemical mixtures. It is clear that a) over the past 100 years chemical regulation and toxicologic research, have in large part, shared a common emphasis on characterization and regulation of individual chemicals. But chemical mixtures have been, and continue to be, evaluated at hazardous waste sites around the United States. For this reason the current U.S. Environmental Protection Agency guidelines for chemical mixtures assessment are also reviewed. These guidelines highlight the current practice of mixtures assessment, which relies primarily on the existing single-chemical database. It is also clear that b) the science and assessment of chemical mixtures are moving forward through the combined efforts of regulatory agencies and scientists from a broad range of disciplines, including toxicology. Because toxicology is at this exciting crossroads, particular attention should be paid to the forces (e.g., public demands, regulatory needs, funding, academic interests) that both promote and limit the growth of this expanding discipline.

  20. Tehran Groundwater Chemical Pollution

    Directory of Open Access Journals (Sweden)

    M- Shariatpanahi

    1990-06-01

    Full Text Available Seventy eight wells water sample of Tehran plain were examined to determine r its groundwaters chemical pollution. Tehran s groundwaters are slightly acidic and their total dissolved solids are high and are in the hard water category."nThe nitrate concentration of wells water of west region is less than per¬missible level of W.H.O. standard, whereas, the nitrate concentration of some of the other regions wells exceed W.H.O. standard which is indication of pollution"nwith municipal wastewaters. The concentration of toxic elements Cr, Cd, As, Hg and"ni Pb of some of the west, east and south regions wells of Tehran is more than per¬missible level of W.H.O. standard, whereas, the concentration of Cu, Zn,Mn and detergents is below W.H.O. standard."n1"nIn general, the amount of dissolved materials of Tehran s groundwaters and also"ni the potential of their contamination with nitrate is increased as Tehran s ground-"nwaters move further to the south, and even though, Tehran s groundwaters contamination with toxic elements is limited to the industrial west district, industrial-residential east and south districts, but»with regard to the disposal methods of"nt municipal and industrial wastewaters, if Tehran s groundwaters pollution continues,"nlocal contamination of groundwaters is likely to spread. So that finally their quality changes in such a way that this water source may become unfit for most domestic, industrial and agricultural uses. This survey shows the necessity of collection and treatment of Tehran s wastewaters and Prevention of the disposal of untreated wastewaters into the environment.

  1. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

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

  2. Modern Chemical Technology, Volume 9.

    Science.gov (United States)

    Pecsok, Robert L.; Chapman, Kenneth

    This volume is one of the series for the Chemical Technician Curriculum Project (ChemTeC) of the American Chemical Society funded by the National Science Foundation. It consists of discussions, exercises, and experiments on the following topics: ion exchange, electrphoresis, dialysis, electrochemistry, corrosion, electrolytic cells, coulometry,…

  3. Job Prospects for Chemical Engineers.

    Science.gov (United States)

    Basta, Nicholas

    1985-01-01

    The job situation for new chemical engineers with bachelor's degrees is continuing to reflect the gradual improvement that began in 1983. However, companies are looking for graduates with technical expertise as well as marketing, sales, or communications skills. Smaller classes may lead to shortages of chemical engineering graduates in the future.…

  4. Teaching Chemical Engineers about Teaching

    Science.gov (United States)

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

    2013-01-01

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

  5. Reduction of chemical reaction models

    Science.gov (United States)

    Frenklach, Michael

    1991-01-01

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

  6. Imprinted photonic crystal chemical sensors

    NARCIS (Netherlands)

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

    2011-01-01

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

  7. Chemical Control of Plant Growth.

    Science.gov (United States)

    Agricultural Research Center (USDA), Beltsville, MD.

    Seven experiments are presented in this Science Study Aid to help students investigate the control of plant growth with chemicals. Plant growth regulators, weed control, and chemical pruning are the topics studied in the experiments which are based on investigations that have been and are being conducted at the U. S. Agricultural Research Center,…

  8. CHEMICAL COMPOUNDS FOR METAL SHAPING

    Science.gov (United States)

    ALLOYS, *CHEMICAL MILLING, *METALS, *REFRACTORY MATERIALS, AIRCRAFT, ALUMINUM ALLOYS, CARBOXYMETHYLCELLULOSE , CHEMICALS, CHROMIUM ALLOYS, GELS, HEAT...RESISTANT ALLOYS, MATERIALS, MOLYBDENUM ALLOYS, NICKEL ALLOYS, NIOBIUM, POROUS MATERIALS, PROCESSING, PRODUCTION , SOLIDS, SOLUTIONS(MIXTURES), STAINLESS STEEL, STEEL, STRUCTURES, TANTALUM, TITANIUM ALLOYS, VANADIUM ALLOYS.

  9. Mathematical Modeling of Chemical Stoichiometry

    Science.gov (United States)

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

    2007-01-01

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

  10. Chemical contamination of material cycles

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Astrup, Thomas Fruergaard

    2015-01-01

    ) chemicals in paper and plastic materials, and furthermore discuss the likely impacts of chemical contamination on material recycling. The work is part of the new Danish initiative focusing on Integrated Resource Management and Recovery (IRMAR, grant no. 11‐116775). The outcomes of the work will provide......Material recycling represents a backbone of sustainable society in the context of circular economy. Ideally, materials are converted into products, used by the consumers, and discarded, just to be recycled and converted into newly manufactured products. Furthermore, materials may also contain...... chemicals, which would be re‐introduced into the loop once a product is recycled. Such chemicals may not be removed in the recycling process, persist, and contaminate the newly manufactured products. Chemical contamination could potentially put product consumers at unnecessary risk and jeopardize public...

  11. How to control chemical hazards

    CERN Multimedia

    2012-01-01

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

  12. Chemical Force Microscopy of Chemical and Biological Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Noy, A

    2006-01-02

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

  13. The role of chemical engineering in pharmaceutical chemical process development.

    Science.gov (United States)

    Landau, R N; Blacklock, T J; Girgis, M J; Tedesco, A

    1998-11-01

    The task of chemical process development in the pharmaceutical industry has grown into a multidisciplinary endeavor requiring years to complete. Increased competition in the pharmaceutical Additionally, the ever-tightening regulatory environment further compromises the business objective (ultimately, profits). This has required careful analysis of the activities within development. This work discusses the results of this analysis, which shows how a balance between minimal resource utilization and phased development achievements can be reached. The cycle of development, from inception to completion, is examined. Special emphasis is placed upon the role of chemical engineering and its appropriate deployment. Simple examples of the synergies that are possible between chemistry and chemical engineering are also given.

  14. Chemical Mapping of Vesta

    Science.gov (United States)

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

    2012-01-01

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

  15. Chemically enabled nanostructure fabrication

    Science.gov (United States)

    Huo, Fengwei

    The first part of the dissertation explored ways of chemically synthesizing new nanoparticles and biologically guided assembly of nanoparticle building blocks. Chapter two focuses on synthesizing three-layer composite magnetic nanoparticles with a gold shell which can be easily functionalized with other biomolecules. The three-layer magnetic nanoparticles, when functionalized with oligonucleotides, exhibit the surface chemistry, optical properties, and cooperative DNA binding properties of gold nanoparticle probes, while maintaining the magnetic properties of the Fe3O4 inner shell. Chapter three describes a new method for synthesizing nanoparticles asymmetrically functionalized with oligonucleotides and the use of these novel building blocks to create satellite structures. This synthetic capability allows one to introduce valency into such structures and then use that valency to direct particle assembly events. The second part of the thesis explored approaches of nanostructure fabrication on substrates. Chapter four focuses on the development of a new scanning probe contact printing method, polymer pen lithography (PPL), which combines the advantages of muCp and DPN to achieve high-throughput, flexible molecular printing. PPL uses a soft elastomeric tip array, rather than tips mounted on individual cantilevers, to deliver inks to a surface in a "direct write" manner. Arrays with as many as ˜11 million pyramid-shaped pens can be brought into contact with substrates and readily leveled optically in order to insure uniform pattern development. Chapter five describes gel pen lithography, which uses a gel to fabricate pen array. Gel pen lithography is a low-cost, high-throughput nanolithography method especially useful for biomaterials patterning and aqueous solution patterning which makes it a supplement to DPN and PPL. Chapter 6 shows a novel form of optical nanolithography, Beam Pen Lithography (BPL), which uses an array of NSOM pens to do nanoscale optical

  16. Method of forming a chemical composition

    Science.gov (United States)

    Bingham, Dennis N.; Wilding, Bruce M.; Klingler, Kerry M.; Zollinger, William T.; Wendt, Kraig M.

    2007-10-09

    A method of forming a chemical composition such as a chemical hydride is described and which includes the steps of selecting a composition having chemical bonds and which is capable of forming a chemical hydride; providing a source of hydrogen; and exposing the selected composition to an amount of ionizing radiation to encourage the changing of the chemical bonds of the selected composition, and chemically reacting the selected composition with the source of hydrogen to facilitate the formation of a chemical hydride.

  17. Chemical munitions dumped at sea

    Science.gov (United States)

    Edwards, Margo; Bełdowski, Jacek

    2016-06-01

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

  18. Ethical guidelines to publication of chemical research. American Chemical Society.

    Science.gov (United States)

    1994-01-01

    The guidelines embodied in this document were revised by the editors of the Publication Division of the American Chemical Society in January 1994 and endorsed by the Society Committee on Publications.

  19. Chemical Demilitarization Assembled Chemical Weapons Alternatives (Chem Demil-ACWA)

    Science.gov (United States)

    2015-12-01

    access machines , two (2) rocket cutting and shearing lines, two (2) neutralization system sampling stations, and three (3) Supercritical Water Oxidation...Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-243 Chemical Demilitarization-Assembled Chemical Weapons Alternatives (Chem Demil-ACWA) As...Abbreviations for MDAP Programs Acq O&M - Acquisition-Related Operations and Maintenance ACAT - Acquisition Category ADM - Acquisition Decision

  20. Chemical microreactor and method thereof

    Science.gov (United States)

    Morse, Jeffrey D.; Jankowski, Alan

    2011-08-09

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

  1. The handling of chemical data

    CERN Document Server

    Lark, P D; Bosworth, R C L

    1968-01-01

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

  2. Selected readings in chemical kinetics

    CERN Document Server

    Back, Margaret H

    2013-01-01

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

  3. Hydrophobic interactions and chemical reactivity

    NARCIS (Netherlands)

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

    2003-01-01

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

  4. Cytoscape file of chemical networks

    Data.gov (United States)

    U.S. Environmental Protection Agency — The maximum connectivity scores of pairwise chemical conditions summarized from Cmap results in a file with Cytoscape format (http://www.cytoscape.org/). The figures...

  5. Mass-sensitive chemical preconcentrator

    Science.gov (United States)

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

    2007-01-30

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

  6. Semiclassical Methods in Chemical Physics.

    Science.gov (United States)

    Miller, William H.

    1986-01-01

    Discusses the role of semiclassical theory in chemical physics both as a computational method and conceptual framework for interpreting quantum mechanical experiments and calculations. Topics covered include energy wells and eigenvalues, scattering, statistical mechanics and electronically nonadiabiatic processes. (JM)

  7. Chemical Potential Dependence of Vertices

    Institute of Scientific and Technical Information of China (English)

    JIANG Yu; ZHANG Yan-Bin; SUN Wei-Min; ZONG Hong-Shi

    2008-01-01

    Based on the rainbow-ladder approximation of the Dyson-Schwinger equations and the assumption of the analyticity of the fermion-boson vertex in the neighborhood of zero chemical potential (μ = 0) and neglecting the μ-dependence of the dressed gluon propagator, we apply the method in [Phys. Rev. C 71 (2005) 015205] of studying the dressed quark propagator at finite chemical potential to prove that the general fermion-boson vertex at finite μ can also be obtained from the one at μ=0 by a simple shift of variables. Using this result we extend the results of [Phys. Lett. B 420 (1998) 267] to the situation of finite chemical potential and show that under the approximations we have taken, the Gell-Mann-Oakes-Renner relation also holds at finite chemical potential.

  8. Introduction to Galactic Chemical Evolution

    CERN Document Server

    Matteucci, Francesca

    2016-01-01

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

  9. Synthetic Biology for Specialty Chemicals.

    Science.gov (United States)

    Markham, Kelly A; Alper, Hal S

    2015-01-01

    In this review, we address recent advances in the field of synthetic biology and describe how those tools have been applied to produce a wide variety of chemicals in microorganisms. Here we classify the expansion of the synthetic biology toolbox into three different categories based on their primary function in strain engineering-for design, for construction, and for optimization. Next, focusing on recent years, we look at how chemicals have been produced using these new synthetic biology tools. Advances in producing fuels are briefly described, followed by a more thorough treatment of commodity chemicals, specialty chemicals, pharmaceuticals, and nutraceuticals. Throughout this review, an emphasis is placed on how synthetic biology tools are applied to strain engineering. Finally, we discuss organism and host strain diversity and provide a future outlook in the field.

  10. Chemical Data Reporting rule (CDR)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset contains information on chemicals that company's produce domestically or import into the United States during the principal reporting year. For the...

  11. Practical Chemical Thermodynamics for Geoscientists

    CERN Document Server

    Fegley, Jr, Bruce

    2012-01-01

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

  12. Chemical ecology of marine sponges

    Digital Repository Service at National Institute of Oceanography (India)

    Thakur, N.L.; Singh, A.

    proto- cols of chemical isolation, and the estimation of natural concentration might not be a true repre- sentative of actual concentrations of the natural product in this sponge (Ma et al. 2009). Besides chemical clues, visual clues such as colour... of the prey can also determine the feeding behaviour. One of the major predators of Antarctic sponges is sea stars which lack visual organ. It was hypo- thesized that the present-day Antarctic sponges still retain visual pigments (e.g. discorhabdins...

  13. The aesthetics of chemical biology.

    Science.gov (United States)

    Parsons, Glenn

    2012-12-01

    Scientists and philosophers have long reflected on the place of aesthetics in science. In this essay, I review these discussions, identifying work of relevance to chemistry and, in particular, to the field of chemical biology. Topics discussed include the role of aesthetics in scientific theory choice, the aesthetics of molecular images, the beauty-making features of molecules, and the relation between the aesthetics of chemical biology and the aesthetics of industrial design.

  14. China's Chemical Pharmaceutical Industry Rebounding

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  15. Photoacoustic Spectroscopy for Chemical Detection

    Science.gov (United States)

    2012-09-01

    Photoacoustic Spectroscopy for Chemical Detection by Ellen L. Holthoff and Paul M. Pellegrino ARL-RP-0410 September 2012...Laboratory Adelphi, MD 20783-1197 ARL-RP-0410 September 2012 Photoacoustic Spectroscopy for Chemical Detection Ellen L. Holthoff and Paul M...ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) September 2012 2. REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Photoacoustic

  16. Chemical pleurodesis for spontaneous pneumothorax.

    Science.gov (United States)

    How, Cheng-Hung; Hsu, Hsao-Hsun; Chen, Jin-Shing

    2013-12-01

    Pneumothorax is defined as the presence of air in the pleural cavity. Spontaneous pneumothorax, occurring without antecedent traumatic or iatrogenic cause, is sub-divided into primary and secondary. The severity of pneumothorax could be varied from asymptomatic to hemodynamically compromised. Optimal management of this benign disease has been a matter of debate. In addition to evacuating air from the pleural space by simple aspiration or chest tube drainage, the management of spontaneous pneumothorax also focused on ceasing air leakage and preventing recurrences by surgical intervention or chemical pleurodesis. Chemical pleurodesis is a procedure to achieve symphysis between the two layers of pleura by sclerosing agents. In the current practice guidelines, chemical pleurodesis is reserved for patients unable or unwilling to receive surgery. Recent researches have found that chemical pleurodesis is also safe and effective in preventing pneumothorax recurrence in patients with the first episode of spontaneous pneumothorax or after thoracoscopic surgery and treating persistent air leakage after thoracoscopic surgery. In this article we aimed at exploring the role of chemical pleurodesis for spontaneous pneumothorax, including ceasing air leakage and preventing recurrence. The indications, choice of sclerosants, safety, effects, and possible side effects or complications of chemical pleurodesis are also reviewed here.

  17. Chemically enhanced in situ recovery

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

  18. How to Protect Yourself from Chemicals

    Science.gov (United States)

    ... yourself from chemicals How to protect yourself from chemicals It may seem kind of scary when you ... glass containers. Staying safe from pesticides, poisons, and chemicals Prevent pesticide poisonings in your house. Have an ...

  19. 78 FR 16698 - Chemical Facility Anti-Terrorism Standards (CFATS) Chemical-Terrorism Vulnerability Information...

    Science.gov (United States)

    2013-03-18

    ... SECURITY Chemical Facility Anti-Terrorism Standards (CFATS) Chemical- Terrorism Vulnerability Information... Collection Request, Chemical Facility Anti- Terrorism Standards (CFATS) Chemical-terrorism Vulnerability... minimize terrorism risk to such facilities. Its design and implementation balance maintaining...

  20. Density Functionals of Chemical Bonding

    Directory of Open Access Journals (Sweden)

    Mihai V. Putz

    2008-06-01

    Full Text Available The behavior of electrons in general many-electronic systems throughout the density functionals of energy is reviewed. The basic physico-chemical concepts of density functional theory are employed to highlight the energy role in chemical structure while its extended influence in electronic localization function helps in chemical bonding understanding. In this context the energy functionals accompanied by electronic localization functions may provide a comprehensive description of the global-local levels electronic structures in general and of chemical bonds in special. Becke-Edgecombe and author’s Markovian electronic localization functions are discussed at atomic, molecular and solid state levels. Then, the analytical survey of the main workable kinetic, exchange, and correlation density functionals within local and gradient density approximations is undertaken. The hierarchy of various energy functionals is formulated by employing both the parabolic and statistical correlation degree of them with the electronegativity and chemical hardness indices by means of quantitative structure-property relationship (QSPR analysis for basic atomic and molecular systems.

  1. Quantum Entanglement and Chemical Reactivity.

    Science.gov (United States)

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

    2015-11-10

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

  2. Scaling up of renewable chemicals.

    Science.gov (United States)

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

    2016-04-01

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

  3. Chemical Hygiene and Safety Plan

    Energy Technology Data Exchange (ETDEWEB)

    Berkner, K.

    1992-08-01

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

  4. Chemical sciences, annual report 1993

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-01

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

  5. Chemical elements distribution in cells

    Science.gov (United States)

    Ortega, R.

    2005-04-01

    Analysing, imaging and understanding the cellular chemistry, from macromolecules to monoatomic elements, is probably a major challenge for the scientific community after the conclusion of the genome project. In order to probe the distribution of elements in cells, especially the so-called inorganic elements, it is necessary to apply microanalytical techniques with sub-micrometer resolution and high chemical sensitivity. This paper presents the current status of chemical element imaging inside cells, and a comparison of the different analytical techniques available: nuclear microprobe, electron microprobe and electron energy loss spectroscopy, synchrotron radiation microprobe, secondary ion mass spectrometry and fluorescence microscopy methods. Examples of intracellular chemical elements distributions relevant to cancer pharmacology, medical imaging, metal carcinogenesis and neuropathology studies obtained by nuclear microprobe and other microanalytical techniques are presented.

  6. Uncoated microcantilevers as chemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Thundat, Thomas G. (Knoxville, TN)

    2001-01-01

    A method and device are provided for chemical sensing using cantilevers that do not use chemically deposited, chemically specific layers. This novel device utilizes the adsorption-induced variation in the surfaces states on a cantilever. The methodology involves exciting charge carriers into or out of the surface states with photons having increasing discrete levels of energy. The excitation energy is provided as discrete levels of photon energy by scanning the wavelength of an exciting source that is illuminating the cantilever surface. When the charge carriers are excited into or out of the surface states, the cantilever bending changes due to changes in surface stress. The amount of cantilever bending with respect to an identical cantilever as a function of excitation energy is used to determine the energy levels associated with adsorbates.

  7. DNA adducts-chemical addons

    Directory of Open Access Journals (Sweden)

    T R Rajalakshmi

    2015-01-01

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

  8. DNA adducts-chemical addons

    Science.gov (United States)

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

    2015-01-01

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

  9. Advanced millimeter wave chemical sensor.

    Energy Technology Data Exchange (ETDEWEB)

    Gopalsami, N.

    1999-03-24

    This paper discusses the development of an advanced millimeter-wave (mm-wave) chemical sensor and its applications for environmental monitoring and arms control treaty verification. The purpose of this work is to investigate the use of fingerprint-type molecular rotational signatures in the mm-wave spectrum to sense airborne chemicals. The mm-wave spectrum to sense airborne chemicals. The mm-wave sensor, operating in the frequency range of 220-300 GHz, can work under all weather conditions and in smoky and dusty environments. The basic configuration of the mm-wave sensor is a monostatic swept-frequency radar consisting of a mm-wave sweeper, a hot-electron-bolometer or Schottky barrier detector, and a trihedral reflector. The chemical plume to be detected is situated between the transmitter/detector and the reflector. Millimeter-wave absorption spectra of chemicals in the plume are determined by measuring the swept-frequency radar return signals with and without the plume in the beam path. The problem of pressure broadening, which hampered open-path spectroscopy in the past, has been mitigated in this work by designing a fast sweeping source over a broad frequency range. The heart of the system is a Russian backward-wave oscillator (BWO) tube that can be tuned over 220-350 GHz. Using the Russian BWO tube, a mm-wave radar system was built and field-tested at the DOE Nevada Test Site at a standoff distance of 60 m. The mm-wave system detected chemical plumes very well; the detection sensitivity for polar molecules like methyl chloride was down to a concentration of 12 ppm.

  10. The chemical and environmental property space of REACH chemicals.

    Science.gov (United States)

    Öberg, Tomas; Iqbal, M Sarfraz

    2012-05-01

    The European regulation on chemicals, REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals), came into force on 1 June 2007. With pre-registration complete in 2008, data for these substances may provide an overview of the expected chemical space and its characteristics. In this paper, using various in silico computation tools, we evaluate 48782 neutral organic compounds from the list to identify hazardous and safe compounds. Two different classification schemes (modified Verhaar and ECOSAR) identified between 17% and 25% of the compounds as expressing only baseline toxicity (narcosis). A smaller portion could be identified as reactive (19%) or specifically acting (2.7%), while the majority were non-assigned (61%). Overall environmental persistence, bioaccumulation and long-range transport potential were evaluated using structure-activity relationships and a multimedia fugacity-based model. A surprisingly high proportion of compounds (20%), mainly aromatic and halogenated, had a very high estimated persistence (>195 d). The proportion of compounds with a very high estimated bioconcentration or bioaccumulation factor (>5000) was substantially less (6.9%). Finally, a list was compiled of those compounds within the applicability domain of the models used, meeting both persistence and bioaccumulation criteria, and with a long-range transport potential comparable to PCB. This list of 68 potential persistent organic pollutants contained many well-known compounds (all halogenated), but notably also five fluorinated compounds that were not included in the EINECS inventory. This study demonstrates the usability of in silico tools for identification of potentially environmentally hazardous chemicals.

  11. The chemical ecology of copepods

    DEFF Research Database (Denmark)

    Heuschele, Jan; Selander, Erik

    2014-01-01

    for the functioning of the marine food web, much is still unknown. We synthesize current knowledge about chemical ecology of copepods including foraging, survival and reproduction. We also compile information on the sensory apparatus and new analytical approaches that may facilitate the identification of signal...... molecules. The review illustrates the importance of chemical interactions in many aspects of copepod ecology and identifies gaps in our knowledge, such as the lack of identified infochemicals and electrophysiological studies to confirm the function of sensory structures. We suggest approaches...

  12. Effort problem of chemical pipelines

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  13. Chemical basis for minimal cognition

    DEFF Research Database (Denmark)

    Hanczyc, Martin; Ikegami, Takashi

    We have developed a simple chemical system capable of self-movement in order to study the chemical-molecular origins of movement, perception and cognition. The system consists simply of an oil droplet in an aqueous environment. The aqueous phase contains a surfactant that modulates the interfacial......-movement. Different from the mere physicalchemical process, any life system preserves its own identity and consistency with respect to the environment. This homeostasis, rooted on the sensory motor couplings, will organize minimal cognition (see also, Ikegami , T. et al., 2008, BioSys., 91, p.388 ]...

  14. Modeling of turbulent chemical reaction

    Science.gov (United States)

    Chen, J.-Y.

    1995-01-01

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

  15. Chemical ecology of marine plankton.

    Science.gov (United States)

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

    2016-07-28

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

  16. Chemical Modification of Food Proteins

    Institute of Scientific and Technical Information of China (English)

    Allaoua Achouri; Wang Zhang; Xu Shiying

    1999-01-01

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

  17. Speeding chemical reactions by focusing

    CERN Document Server

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

    2012-01-01

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

  18. Chemical patterning in biointerface science

    Directory of Open Access Journals (Sweden)

    Ryosuke Ogaki

    2010-04-01

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

  19. Chemical kinetics and reaction dynamics

    CERN Document Server

    Houston, Paul L

    2006-01-01

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

  20. Method of producing a chemical hydride

    Science.gov (United States)

    Klingler, Kerry M.; Zollinger, William T.; Wilding, Bruce M.; Bingham, Dennis N.; Wendt, Kraig M.

    2007-11-13

    A method of producing a chemical hydride is described and which includes selecting a composition having chemical bonds and which is capable of forming a chemical hydride; providing a source of a hydrocarbon; and reacting the composition with the source of the hydrocarbon to generate a chemical hydride.

  1. A theory of chemicals regulation and testing

    NARCIS (Netherlands)

    Gabbert, S.G.M.; Weikard, H.P.

    2010-01-01

    Risk management of chemicals requires information about their adverse effects such as toxicity and persistence, for example. Testing of chemicals allows for improving the information base for regulatory decision-making on chemicals' production and use. Testing a large number of chemicals with limite

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

    Directory of Open Access Journals (Sweden)

    Lei Chen

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

  3. The complex chemical Langevin equation.

    Science.gov (United States)

    Schnoerr, David; Sanguinetti, Guido; Grima, Ramon

    2014-07-14

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

  4. The Symbolism Of Chemical Equations

    Science.gov (United States)

    Jensen, William B.

    2005-01-01

    A question about the historical origin of equal sign and double arrow symbolism in balanced chemical equation is raised. The study shows that Marshall proposed the symbolism in 1902, which includes the use of currently favored double barb for equilibrium reactions.

  5. Sustainability in Chemical Engineering Curriculum

    Science.gov (United States)

    Glassey, Jarka; Haile, Sue

    2012-01-01

    Purpose: The purpose of this paper is to describe a concentrated strategy to embed sustainability teaching into a (chemical) engineering undergraduate curriculum throughout the whole programme. Innovative teaching approaches in subject-specific context are described and their efficiency investigated. Design/methodology/approach: The activities in…

  6. Chemical kinetics on extrasolar planets.

    Science.gov (United States)

    Moses, Julianne I

    2014-04-28

    Chemical kinetics plays an important role in controlling the atmospheric composition of all planetary atmospheres, including those of extrasolar planets. For the hottest exoplanets, the composition can closely follow thermochemical-equilibrium predictions, at least in the visible and infrared photosphere at dayside (eclipse) conditions. However, for atmospheric temperatures approximately extrasolar planets.

  7. Toxicological evaluation of chemical mixtures

    NARCIS (Netherlands)

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

    2002-01-01

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

  8. Chemical reaction and separation method

    NARCIS (Netherlands)

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

    2005-01-01

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

  9. 76 FR 14818 - Chemical Testing

    Science.gov (United States)

    2011-03-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 46 CFR Part 16 Chemical Testing CFR Correction In Title 46 of the Code of Federal Regulations, Parts 1 to 40, revised as of October 1, 2010, on page 254, in Sec. 16.105, in the definition...

  10. Chemical synthesis on SU-8

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  11. Cosmetics - chemical technology or biotechnology?

    Science.gov (United States)

    Allen, G

    1984-04-01

    Synopsis Over the past 25 years the cosmetic industry has become increasingly technological. The origins of many of these advances were based upon chemical technology usually related to colloid science, although more recent developments have had clear biological improvements. A number of recent innovations are examined to consider how far developments in the future will stem from biotechnology rather than chemical technology. The working of surface active materials (e.g. CTAB) is discussed as an example of cosmetic effects being generated purely from chemical technology. The role of fluoride toothpaste in decreasing the incidence of dental caries is discussed as an effect based essentially on chemical technology in an area where future alternatives might come from biotechnology. Skin research is highlighted as the area where new understanding, e.g. of the role of epidermal growth factor (EGF), fibronectin and laminin, could lead to a whole new biotechnological approach to the appraisal of skin. As we venture into innovations based on biotechnology we may be introducing new dimensions in product safety which will need an even closer relationship with the medical fraternity. Consequently the introduction of products based on biotechnology may not be as rapid as is sometimes suggested.

  12. Introduction to Galactic Chemical Evolution

    Science.gov (United States)

    Matteucci, Francesca

    2016-04-01

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

  13. Chemical constituents from Schisandra sphenanthera

    Institute of Scientific and Technical Information of China (English)

    Rong Tao Li; Zhi Ying Weng; Jian Xin Pu; Han Dong Sun

    2008-01-01

    The chemical constituents of the stems of Schisandra sphenanthera are described for the first time. This investigation has resulted in the isolation of a new phenolic glycoside (1), along with seven known compounds. The structure of 1 was assigned by using spectroscopic techniques, including 2D NMR spectra.

  14. The chemical ecology of copepods

    DEFF Research Database (Denmark)

    Heuschele, Jan; Selander, Erik

    2014-01-01

    for the functioning of the marine food web, much is still unknown. We synthesize current knowledge about chemical ecology of copepods including foraging, survival and reproduction. We also compile information on the sensory apparatus and new analytical approaches that may facilitate the identification of signal...

  15. Environmental chemicals and thyroid function

    DEFF Research Database (Denmark)

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

    2009-01-01

    PURPOSE OF REVIEW: To overview the effects of endocrine disrupters on thyroid function. RECENT FINDINGS: Studies in recent years have revealed thyroid-disrupting properties of many environmentally abundant chemicals. Of special concern is the exposure of pregnant women and infants, as thyroid...

  16. Integrated opto-chemical sensors

    NARCIS (Netherlands)

    Lambeck, Paul V.

    1992-01-01

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

  17. Has Chemical Education Reached Equilibrium?

    Science.gov (United States)

    Moore, John W.

    1997-06-01

    The other day I got to thinking about whether something akin to Le Chatelier's principle operates in chemical education. That is, whenever someone alters the conditions under which we interact with students, there is a shift in the system that attempts to minimize or counteract the change.

  18. The Chemical Composition of Honey

    Science.gov (United States)

    Ball, David W.

    2007-01-01

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

  19. Chemical constituents of Tephrosia purpurea.

    Science.gov (United States)

    Khalafalah, Ali K; Yousef, Afifi H; Esmail, Abeer M; Abdelrazik, Mohamed H; Hegazy, Mohamed E F; Mohamed, Abou-El-Hamd H

    2010-03-01

    In continuation of our chemical investigation on some medicinal plants of the genus Tephrosia, reinvestigation of the methylenechloride/methanol (1:1) extract of the aerial parts of Tephrosia purpurea yielded an aromatic ester 1, a sesquiterpene 2 and prenylated flavonoid 3. The structures of the compounds were established by comprehensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC, EIMS and CIMS.

  20. Chemical constituents of Tephrosia purpurea

    OpenAIRE

    Khalafalah, Ali K.; Yousef, Afifi H.; Abeer M Esmail; Abdelrazik, Mohamed H.; Hegazy, Mohamed E. F.; Abou-El-Hamd H Mohamed

    2010-01-01

    In continuation of our chemical investigation on some medicinal plants of the genus Tephrosia, reinvestigation of the methylenechloride/methanol (1:1) extract of the aerial parts of Tephrosia purpurea yielded an aromatic ester 1, a sesquiterpene 2 and prenylated flavonoid 3. The structures of the compounds were established by comprehensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC, EIMS and CIMS.

  1. Physico-chemical wastewater treatment

    NARCIS (Netherlands)

    Mels, A.R.; Teerikangas, E.

    2002-01-01

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

  2. Simple Chemical Vapor Deposition Experiment

    Science.gov (United States)

    Pedersen, Henrik

    2014-01-01

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

  3. Apparent tunneling in chemical reactions

    DEFF Research Database (Denmark)

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

    2000-01-01

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

  4. Biological and Chemical Information Technologies

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  5. 2010 Chemical Working Group Status

    Science.gov (United States)

    Reid, Concha M.

    2010-01-01

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

  6. Chemical Fibers: Shaking off Predicament

    Institute of Scientific and Technical Information of China (English)

    Zheng Junlin

    2007-01-01

    @@ Overall improvement in 2006 In spite of unfavorable factors such as high raw material prices, textile export rebate reduction, export growth slowdown, aggravated international trade friction and sustained Renminbi appreciation, producers in the chemical fiber sector accelerated technical progress and structure readjustment and achieved satisfactory overall performance in 2006.

  7. Toxicokinetic Triage for Environmental Chemicals

    Science.gov (United States)

    Toxicokinetic (TK) models are essential for linking administered doses to blood and tissue concentrations. In vitro-to-in vivo extrapolation (IVIVE) methods have been developed to determine TK from limited in vitro measurements and chemical structure-based property predictions, p...

  8. Chemical Protection Against Ionizing Radiation.

    Science.gov (United States)

    1984-08-01

    experimentally obtained. SPONSOR: Div of Cancer Treatment, NIH /A TOPICS: 2D PI/ORG: Moss, Alfred J; Veterans Administration Ned Ctr, Little Rock AR TITLE...Robert C; Dartmouth- Hitchcock Ned Ctr, Hanover NH TITLE: Radiation-chemical induction of mutagenesis. SUMMARY: Effects of sensitizers on radiation

  9. Extended range chemical sensing apparatus

    Science.gov (United States)

    Hughes, Robert C.; Schubert, W. Kent

    1994-01-01

    An apparatus for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy.

  10. Probing Chemical Dynamics at Surfaces

    Institute of Scientific and Technical Information of China (English)

    KLEYN, A.W.; KLEYN, A.W

    2001-01-01

    An account is given of recent progress concerning chemical reaction dynamics at surfaces. The goal is to elucidate the reaction dynamics at the molecular level, both as time and distance is concerned. The methods of study include molecular beam scattering, scanning tunnelling microscopy, and (femtosecond) laser spectroscopy. Systems studied include elementary interactions of NO, CO, and O2 at single crystal metal surfaces.

  11. Safe use of hazardous chemicals.

    Science.gov (United States)

    Lunn, George; Lawler, Gretchen

    2011-11-01

    This unit provides protocols for some commonly used disposal and decontamination procedures along with analytical techniques that are used to verify that reagents have been decontaminated. Some of the specific reagents covered are diaminobenzidine, ethidium bromide, cyanogen bromide, and chloromethylsilane. With modification, these assays may also be used to determine the concentration of a particular chemical.

  12. Substrates: Chemical characteristics and preparation

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2009-01-01

    In this chapter the characteristics of substrates will be discussed with respect to their effects on plant nutrition. Therefore, the chemical composition will be taken into account in the first place, because the mineral elements present in the material can be directly available to plants or can bec

  13. Odor from a chemical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Wray, T.K.

    1995-06-01

    Early odor-detection measurements categorized chemicals according to odor quality. Recent methods focus on the odor threshold, or the quantitative amount of a chemical in air that can be detected by the human sense of smell. Researchers characterize and quantify odor using an array of sensory and analytical procedures. Humans possess one of the dullest mammalian senses of smell; however, they can recognize about 10,000 distinct odors at concentrations ranging from less than 1 part per billion to several hundred thousand parts per million. Each time humans inhale, they chemically analyze microscopic pieces of the environment that make physical contact with the nerves in their noses. Individual molecules travel up the nose to a sheet of moist, mucus-bathed tissue that consists of about 5 million smell-sensing, olfactory neurons. After dissolving in the mucus, odor molecules ``float`` into appropriately shaped receptor pockets. A series of cellular reactions then transmit impulses to the limbic system, hippocampus and, finally, the neocortex. Odor detection is an important defense mechanism. The author presents the odor thresholds for selected organic compounds, and other hazardous chemicals.

  14. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    1969-01-01

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

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

    Science.gov (United States)

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

    1996-11-01

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

  16. Effect of Chemicals on Chemical Mechanical Polishing of Glass Substrates

    Institute of Scientific and Technical Information of China (English)

    WANG Liang-Yong; ZHANG Kai-Liang; SONG Zhi-Tang; FENG Song-Lin

    2007-01-01

    @@ We investigate the effect of chemicals on chemical mechanical polishing (CMP) of glass substrates. Ceria slurry in an ultra-low concentration of 0.25wt.% is used and characterized by scanning electron microscopy. Three typical molecules, i.e. acetic acid, citric acid and sodium acrylic polymer, are adopted to investigate the effect on CMP performance in terms of material removal rate (MRR) and surface quality. The addition of sodium acrylic polymer shows the highest MRR as well as the best surface by atomic force microscopy after CMP, vhile the addition of citric acid shows the worst performance. These results reveal a mechanism that a long-chain molecule without any branches rather than small molecules and common molecules with ramose abundant-electron groups is better for the dispersion of the slurry and thus better for the CMP process.

  17. Dryden Flight Research Center Chemical Pharmacy Program

    Science.gov (United States)

    Davis, Bette

    1997-01-01

    The Dryden Flight Research Center (DFRC) Chemical Pharmacy "Crib" is a chemical sharing system which loans chemicals to users, rather than issuing them or having each individual organization or group purchasing the chemicals. This cooperative system of sharing chemicals eliminates multiple ownership of the same chemicals and also eliminates stockpiles. Chemical management duties are eliminated for each of the participating organizations. The chemical storage issues, hazards and responsibilities are eliminated. The system also ensures safe storage of chemicals and proper disposal practices. The purpose of this program is to reduce the total releases and transfers of toxic chemicals. The initial cost of the program to DFRC was $585,000. A savings of $69,000 per year has been estimated for the Center. This savings includes the reduced costs in purchasing, disposal and chemical inventory/storage responsibilities. DFRC has chemicals stored in 47 buildings and at 289 locations. When the program is fully implemented throughout the Center, there will be three chemical locations at this facility. The benefits of this program are the elimination of chemical management duties; elimination of the hazard associated with chemical storage; elimination of stockpiles; assurance of safe storage; assurance of proper disposal practices; assurance of a safer workplace; and more accurate emissions reports.

  18. Chemical Visualization of Boolean Functions: A Simple Chemical Computer

    Science.gov (United States)

    Blittersdorf, R.; Müller, J.; Schneider, F. W.

    1995-08-01

    We present a chemical realization of the Boolean functions AND, OR, NAND, and NOR with a neutralization reaction carried out in three coupled continuous flow stirred tank reactors (CSTR). Two of these CSTR's are used as input reactors, the third reactor marks the output. The chemical reaction is the neutralization of hydrochloric acid (HCl) with sodium hydroxide (NaOH) in the presence of phenolphtalein as an indicator, which is red in alkaline solutions and colorless in acidic solutions representing the two binary states 1 and 0, respectively. The time required for a "chemical computation" is determined by the flow rate of reactant solutions into the reactors since the neutralization reaction itself is very fast. While the acid flow to all reactors is equal and constant, the flow rate of NaOH solution controls the states of the input reactors. The connectivities between the input and output reactors determine the flow rate of NaOH solution into the output reactor, according to the chosen Boolean function. Thus the state of the output reactor depends on the states of the input reactors.

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

    NARCIS (Netherlands)

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

    2004-01-01

    Recent developments in hazard identification and risk assessment of chemical mixtures are reviewed. Empirical, descriptive approaches to study and characterize the toxicity of mixtures have dominated during the past two decades, but an increasing number of mechanistic approaches have made their entr

  20. 46 CFR 190.05-20 - Segregation of chemical laboratories and chemical storerooms.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Segregation of chemical laboratories and chemical... chemical laboratories and chemical storerooms. (a) The provisions of this section shall apply to all vessels contracted for on or after March 1, 1968. (b) Chemical storerooms shall not be located...

  1. A New Paradigm for Chemical Engineering?

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    businesses has been observed. There is an increasing trend within the chemical industry to focus on products and the sustainable processes that can make them. Do these changes point to a paradigm shift in chemical engineering as a discipline? Historically, two previous paradigm shifts in chemical engineering...... corresponded to major shifts in chemical engineering as a discipline, which affected not only the education of chemical engineers, but also the development of chemical engineering as a discipline. Has the time come for a new paradigm shift that will prepare the current and future chemical engineering graduates...... to tackle the complex problems facing the chemicals based industries and serve the modern society more efficiently? The lecture will review the current status of chemical engineering as a discipline, the proposals for the third paradigm, the need for such a paradigm shift and related educational issues....

  2. Chemical Protein Modification through Cysteine.

    Science.gov (United States)

    Gunnoo, Smita B; Madder, Annemieke

    2016-04-01

    The modification of proteins with non-protein entities is important for a wealth of applications, and methods for chemically modifying proteins attract considerable attention. Generally, modification is desired at a single site to maintain homogeneity and to minimise loss of function. Though protein modification can be achieved by targeting some natural amino acid side chains, this often leads to ill-defined and randomly modified proteins. Amongst the natural amino acids, cysteine combines advantageous properties contributing to its suitability for site-selective modification, including a unique nucleophilicity, and a low natural abundance--both allowing chemo- and regioselectivity. Native cysteine residues can be targeted, or Cys can be introduced at a desired site in a protein by means of reliable genetic engineering techniques. This review on chemical protein modification through cysteine should appeal to those interested in modifying proteins for a range of applications.

  3. [Chemical constituents of Desmodium sambuense].

    Science.gov (United States)

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

    2010-09-01

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

  4. The chemical diversity of comets

    CERN Document Server

    Crovisier, J; Bockelée-Morvan, D; Boissier, J; Colom, P; Lis, D C

    2009-01-01

    A fundamental question in cometary science is whether the different dynamical classes of comets have different chemical compositions, which would reflect different initial conditions. From the ground or Earth orbit, radio and infrared spectroscopic observations of a now significant sample of comets indeed reveal deep differences in the relative abundances of cometary ices. However, no obvious correlation with dynamical classes is found. Further results come, or are expected, from space exploration. Such investigations, by nature limited to a small number of objects, are unfortunately focussed on short-period comets (mainly Jupiter-family). But these in situ studies provide "ground truth" for remote sensing. We discuss the chemical differences in comets from our database of spectroscopic radio observations, which has been recently enriched by several Jupiter-family and Halley-type comets.

  5. Waste management and chemical inventories

    Energy Technology Data Exchange (ETDEWEB)

    Gleckler, B.P.

    1995-06-01

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

  6. Wide-Area Chemical Sensor

    Science.gov (United States)

    2014-11-01

    2014www.ll.mit.edu The detection and localization of gas releases such as methane from leaking natural gas pipelines or nitrogen oxides from failing electrical...reference gas cells, such as methane buffered by nitro- gen, and a low-concentration gas cell that contains the target species to calibrate the...self-referencing technique employed by WACS is particularly suited to detecting chemical agents composed of primarily small molecules— methane , various

  7. Chemical Classification of Space Debris

    Institute of Scientific and Technical Information of China (English)

    LI Chunlai; ZUO Wei; LIU Jianjun; OUYANG Ziyuan

    2004-01-01

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

  8. Chemical evolution of star clusters

    OpenAIRE

    van Loon, Jacco Th.

    2009-01-01

    I discuss the chemical evolution of star clusters, with emphasis on old globular clusters, in relation to their formation histories. Globular clusters clearly formed in a complex fashion, under markedly different conditions from any younger clusters presently known. Those special conditions must be linked to the early formation epoch of the Galaxy and must not have occurred since. While a link to the formation of globular clusters in dwarf galaxies has been suggested, present-day dwarf galaxi...

  9. Origin of the Chemical Elements

    CERN Document Server

    Rauscher, T

    2010-01-01

    This review provides the necessary background from astrophysics, nuclear, and particle physics to understand the cosmic origin of the chemical elements. It reflects the year 2009 state of the art in this extremely quickly developing interdisciplinary research direction. The discussion summarizes the nucleosynthetic processes in the course of the evolution of the Universe and the galaxies contained within, including primordial nucleosynthesis, stellar evolution, and explosive nucleosynthesis in single and binary systems.

  10. Monitoring advances in chemical engineering

    OpenAIRE

    Peters, H.P.F.; Hartmann, D; Van Raan, A.F.J.

    1988-01-01

    This paper describes an approach to monitoring scientific progress in chemical engineering in order to operationalize concepts such as 'research performance' which can be used in the retrospective evaluation and the future anticipation of scientific research activities. We focus on various quantitative methods. Bibliometric methods form an important, but not the only, part of the work. The use of bibliometric approaches and measures is plagued by many problems. This is es...

  11. The Toxicity of Photographic Chemicals.

    Science.gov (United States)

    1980-10-01

    Silver Nitrate Sodium Bisulfate (Sodium Acid Sulfate) Sulfuric Acid Succi nal dehyde The chemicals listed above are all extremely corrosive to the skin... Acid , Glacial Ammonia ( Ammonium Hydroxide, Ammonia Water, Household Ammonia)I Formaldehyde, 37-percent Solution (Formal in) Hydrochloric Acid Hydrogen...vapors, acid vapors such as from acetic acid baths, and breakdown products such as sulfur dioxide over fix and stop baths require local fume exhaust

  12. Chemical equilibrium modeling of detonation

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-05-19

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

  13. Chemical constituents of Tephrosia purpurea

    Directory of Open Access Journals (Sweden)

    Ali K Khalafalah

    2010-01-01

    Full Text Available In continuation of our chemical investigation on some medicinal plants of the genus Tephrosia, reinvestigation of the methylenechloride/methanol (1:1 extract of the aerial parts of Tephrosia purpurea yielded an aromatic ester 1, a sesquiterpene 2 and prenylated flavonoid 3. The structures of the compounds were established by comprehensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC, EIMS and CIMS.

  14. Chemical logging of geothermal wells

    Science.gov (United States)

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

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

  15. Chemical engineering of molecular qubits.

    Science.gov (United States)

    Wedge, C J; Timco, G A; Spielberg, E T; George, R E; Tuna, F; Rigby, S; McInnes, E J L; Winpenny, R E P; Blundell, S J; Ardavan, A

    2012-03-09

    We show that the electron spin phase memory time, the most important property of a molecular nanomagnet from the perspective of quantum information processing, can be improved dramatically by chemically engineering the molecular structure to optimize the environment of the spin. We vary systematically each structural component of the class of antiferromagnetic Cr(7)Ni rings to identify the sources of decoherence. The optimal structure exhibits a phase memory time exceeding 15  μs.

  16. Chemically Assisted Photocatalytic Oxidation System

    Science.gov (United States)

    Andino, Jean; Wu, Chang-Yu; Mazyck, David; Teixeira, Arthur A.

    2009-01-01

    The chemically assisted photocatalytic oxidation system (CAPOS) has been proposed for destroying microorganisms and organic chemicals that may be suspended in the air or present on surfaces of an air-handling system that ventilates an indoor environment. The CAPOS would comprise an upstream and a downstream stage that would implement a tandem combination of two partly redundant treatments. In the upstream stage, the air stream and, optionally, surfaces of the air-handling system would be treated with ozone, which would be generated from oxygen in the air by means of an electrical discharge or ultraviolet light. In the second stage, the air laden with ozone and oxidation products from the first stage would be made to flow in contact with a silica-titania photocatalyst exposed to ultraviolet light in the presence of water vapor. Hydroxyl radicals generated by the photocatalytic action would react with both carbon containing chemicals and microorganisms to eventually produce water and carbon dioxide, and ozone from the first stage would be photocatalytically degraded to O2. The net products of the two-stage treatment would be H2O, CO2, and O2.

  17. Chemical Evolution of M31

    CERN Document Server

    Matteucci, F

    2014-01-01

    We review chemical evolution models developed for M31 as well as the abundance determinations available for this galaxy. Then we present a recent chemical evolution model for M31 including radial gas flows and galactic fountains along the disk, as well as a model for the bulge. Our models are predicting the evolution of the abundances of several chemical species such as H, He, C, N, O, Ne, Mg, Si, S, Ca and Fe. From comparison between model predictions and observations we can derive some constraints on the evolution of the disk and the bulge of M31. We reach the conclusions that Andromeda must have evolved faster than the Milky Way and inside-out, and that its bulge formed much faster than the disk on a timescale $\\leq$ 0.5 Gyr. Finally, we present a study where we apply the model developed for the disk of M31 in order to study the probability of finding galactic habitable zones in this galaxy.

  18. Chemical recycling of scrap composites

    Science.gov (United States)

    Allred, Ronald E.; Salas, Richard M.

    1994-01-01

    There are no well-developed technologies for recycling composite materials other than grinding to produce fillers. New approaches are needed to reclaim these valuable resources. Chemical or tertiary recycling, conversion of polymers into low molecular weight hydrocarbons for reuse as chemicals or fuels, is emerging as the most practical means for obtaining value from waste plastics and composites. Adherent Technologies is exploring a low-temperature catalytic process for recycling plastics and composites. Laboratory results show that all types of plastics, thermosets as well as thermoplastics, can be converted in high yields to valuable hydrocarbon products. This novel catalytic process runs at 200 C, conversion times are rapid, the process is closed and, thus, nonpolluting, and no highly toxic gas or liquid products have been observed so no negative environmental impact will result from its implementation. Tests on reclamation of composite materials show that epoxy, imide, and engineering thermoplastic matrices can be converted to low molecular weight hydrocarbons leaving behind the reinforcing fibers for reuse as composite reinforcements in secondary, lower-performance applications. Chemical recycling is also a means to dispose of sensitive or classified organic materials without incineration and provides a means to eliminate or reduce mixed hazardous wastes containing organic materials.

  19. Chemical substructure search in SQL.

    Science.gov (United States)

    Golovin, Adel; Henrick, Kim

    2009-01-01

    We present a novel technique for a fast chemical substructure search on a relational database by use of a standard SQL query. The symmetry of a query graph is analyzed to give additional constraints. Our method is based on breadth-first search (BFS) algorithms implementation using Relational Database Management Systems (RDBMS). In addition to the chemical search we apply our technique to the field of intermolecular interactions which involves nonplanar graphs and describe how to achieve linear time performance along with the suggestion on how to sufficiently reduce the linear coefficient. From the algorithms theory perspective these results mean that subgraph isomorphism is a polynomial time problem, hence equal problems have the same complexity. The application to subgraph isomorphism in chemical search is available at http://www.ebi.ac.uk/msd-srv/chemsearch and http://www.ebi.ac.uk/msd-srv/msdmotif/chem . The application to the network of molecule interactions is available at http://www.ebi.ac.uk/msd-srv/msdmotif .

  20. Passive in-situ chemical sensor

    Science.gov (United States)

    Morrell, Jonathan S.; Ripley, Edward B.

    2012-02-14

    A chemical sensor for assessing a chemical of interest. In typical embodiments the chemical sensor includes a first thermocouple and second thermocouple. A reactive component is typically disposed proximal to the second thermal couple, and is selected to react with the chemical of interest and generate a temperature variation that may be detected by a comparison of a temperature sensed by the second thermocouple compared with a concurrent temperature detected by the first thermocouple. Further disclosed is a method for assessing a chemical of interest and a method for identifying a reaction temperature for a chemical of interest in a system.

  1. 77 FR 74685 - Chemical Facility Anti-Terrorism Standards (CFATS) Chemical-Terrorism Vulnerability Information...

    Science.gov (United States)

    2012-12-17

    ... SECURITY Chemical Facility Anti-Terrorism Standards (CFATS) Chemical- Terrorism Vulnerability Information... financial information, Chemical-terrorism Vulnerability Information (CVI), Sensitive Security Information... represents a national-level effort to minimize terrorism risk to such facilities. Its design...

  2. Predicting Drugs Side Effects Based on Chemical-Chemical Interactions and Protein-Chemical Interactions

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2013-01-01

    Full Text Available A drug side effect is an undesirable effect which occurs in addition to the intended therapeutic effect of the drug. The unexpected side effects that many patients suffer from are the major causes of large-scale drug withdrawal. To address the problem, it is highly demanded by pharmaceutical industries to develop computational methods for predicting the side effects of drugs. In this study, a novel computational method was developed to predict the side effects of drug compounds by hybridizing the chemical-chemical and protein-chemical interactions. Compared to most of the previous works, our method can rank the potential side effects for any query drug according to their predicted level of risk. A training dataset and test datasets were constructed from the benchmark dataset that contains 835 drug compounds to evaluate the method. By a jackknife test on the training dataset, the 1st order prediction accuracy was 86.30%, while it was 89.16% on the test dataset. It is expected that the new method may become a useful tool for drug design, and that the findings obtained by hybridizing various interactions in a network system may provide useful insights for conducting in-depth pharmacological research as well, particularly at the level of systems biomedicine.

  3. Airborne chemical contamination of a chemically amplified resist

    Science.gov (United States)

    MacDonald, Scott A.; Clecak, Nicholas J.; Wendt, H. R.; Willson, C. Grant; Snyder, Clinton D.; Knors, C. J.; Deyoe, N. B.; Maltabes, John G.; Morrow, James R.; McGuire, Anne E.; Holmes, Steven J.

    1991-06-01

    We have found that the performance of the t-BOC/onium salt resist system is severely degraded by vapor from organic bases. This effect is very pronounced and can be observed when the coated wafers stand for 15 minutes in air containing as little as 15 parts per billion (ppb) of an organic base. The observed effect, caused by this chemical contamination, depends on the tone of the resist system. For negative tone systems the UV exposure dose, required to obtain the correct linewidth, increases. While for the positive tone system, one observes the generation of a skin at the resist-air interface. Both effects are caused by the photogenerated acid being neutralized by the airborne organic base. There are a wide variety of commonly used materials which can liberate trace amounts of volatile amines and degrade resist performance. For example, fresh paint on a laboratory wall can exhibit this detrimental effect. These effects can be minimized by storing and processing the resist coated wafers in air that has passed through a specially designed, high efficiency carbon filter. The implementation of localized air filtration, to bathe the resist in chemically pure air, enabled this resist system to operate in a manufacturing environment at a rate of 100 wafers/hour.

  4. Development Trends of Electronic Chemicals in China

    Institute of Scientific and Technical Information of China (English)

    Zheng Jinhong; Hou Hongsen

    2007-01-01

    @@ The annual growth of the electronic chemicals business in China exceeded 20% during the Tenth Five-year Plan period (2001-2005). The market volume of electronic chemicals in China is expected to exceed RMB20 billion in 2010.

  5. Liaotong Chemical: Create a Large Petrochemical Enterprise

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Since its listing in the stock market, Liaotong Huajin Tongda Chemicals Co., Ltd.(Liaotong Chemical, SZ:000059) has paid off bank loans with funds raised in the stock market to reduce its capital cost.

  6. Electrochemical, Chemical and Enzymatic Oxidations of Phenothiazines

    NARCIS (Netherlands)

    Blankert, B.; Hayen, H.; Leeuwen, van S.M.; Karst, U.; Bodoki, E.; Lotrean, S.; Sandulescu, R.; Mora Diaz, N.; Dominguez, O.; Arcos, J.; Kauffmann, J.-M.

    2005-01-01

    The oxidation of several phenothiazine drugs (phenothiazine, promethazine hydrochloride, promazine hydrochloride, trimeprazine hydrochloride and ethopropazine hydrochloride) has been carried out in aqueous acidic media by electrochemical, chemical and enzymatic methods. The chemical oxidation was pe

  7. Chemical and thermal stability of insulin

    DEFF Research Database (Denmark)

    Huus, Kasper; Havelund, Svend; Olsen, Helle B;

    2006-01-01

    To study the correlation between the thermal and chemical stability of insulin formulations with various insulin hexamer ligands.......To study the correlation between the thermal and chemical stability of insulin formulations with various insulin hexamer ligands....

  8. Chemical Mechanism Solvers in Air Quality Models

    Directory of Open Access Journals (Sweden)

    John C. Linford

    2011-09-01

    Full Text Available The solution of chemical kinetics is one of the most computationally intensivetasks in atmospheric chemical transport simulations. Due to the stiff nature of the system,implicit time stepping algorithms which repeatedly solve linear systems of equations arenecessary. This paper reviews the issues and challenges associated with the construction ofefficient chemical solvers, discusses several families of algorithms, presents strategies forincreasing computational efficiency, and gives insight into implementing chemical solverson accelerated computer architectures.

  9. Nonlinear Chemical Dynamics and Synchronization

    Science.gov (United States)

    Li, Ning

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

  10. [Chemical constituents of Physalis pubescens].

    Science.gov (United States)

    Luo, Li-ping; Cheng, Fan-qin; Ji, Long; Yu, He-yong

    2015-11-01

    Chemical constituents of 95% ethanol extract of the dried persistent calyx of Physalis pubescens were investigated. By chromatography on a silica gel column and reverse-phase preparative HPLC, 10 compounds were isolated from the dichloromethane fraction. Based on the MS and 1D/2D NMR data, these compounds were identified as 5-O-(E-feruloyl) blumenol (1), isovanillin (2), (E) -ethyl 3-(4-hydroxyphenyl) acrylate (3), 4-hydroxybenzaldehyde(4), 4-methylphenol (5), (E) -methyl cinnamate (6), 7,3',4' trimethoxyquercetin (7), 5,3', 5'-trihydroxy-3,7,4'-trimethoxyflavone(8), danielone (9), and 5,5'-diisobutoxy-2,2'-bifuran (10).

  11. Optimal control for chemical engineers

    CERN Document Server

    Upreti, Simant Ranjan

    2013-01-01

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

  12. Kinematically complete chemical reaction dynamics

    Science.gov (United States)

    Trippel, S.; Stei, M.; Otto, R.; Hlavenka, P.; Mikosch, J.; Eichhorn, C.; Lourderaj, U.; Zhang, J. X.; Hase, W. L.; Weidemüller, M.; Wester, R.

    2009-11-01

    Kinematically complete studies of molecular reactions offer an unprecedented level of insight into the dynamics and the different mechanisms by which chemical reactions occur. We have developed a scheme to study ion-molecule reactions by velocity map imaging at very low collision energies. Results for the elementary nucleophilic substitution (SN2) reaction Cl- + CH3I → ClCH3 + I- are presented and compared to high-level direct dynamics trajectory calculations. Furthermore, an improved design of the crossed-beam imaging spectrometer with full three-dimensional measurement capabilities is discussed and characterization measurements using photoionization of NH3 and photodissociation of CH3I are presented.

  13. Personal Simulator of Chemical Process

    Institute of Scientific and Technical Information of China (English)

    吴重光

    2002-01-01

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

  14. PNA-encoded chemical libraries.

    Science.gov (United States)

    Zambaldo, Claudio; Barluenga, Sofia; Winssinger, Nicolas

    2015-06-01

    Peptide nucleic acid (PNA)-encoded chemical libraries along with DNA-encoded libraries have provided a powerful new paradigm for library synthesis and ligand discovery. PNA-encoding stands out for its compatibility with standard solid phase synthesis and the technology has been used to prepare libraries of peptides, heterocycles and glycoconjugates. Different screening formats have now been reported including selection-based and microarray-based methods that have yielded specific ligands against diverse target classes including membrane receptors, lectins and challenging targets such as Hsp70.

  15. Chemical and Biological Resistant Clothing

    Science.gov (United States)

    2013-04-01

    Dehydration was confirmed by CuSO4 (dry CuSO4 turns light blue upon contacting water). The influence of DMMP adsorption on the zeolite external surface...temperature. Table 16. Saturated Vapor Pressure (PSaturated) at Room Temperature Chemical PSaturated (mm Hg ) Water 4.54 DMMP 0.34 TBP 0.004 MS...to enter the pores of zeolite-A and its adsorption on the zeolite external surface is apparently negligible in the IPA liquid environment. The GC

  16. Speciality chemicals from synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-04-01

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

  17. Chemical kinetics and combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-01

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

  18. Chemical Constituents of Euphorbia ebracteolata

    Institute of Scientific and Technical Information of China (English)

    SHIHai-ming; MINZhi-da

    2004-01-01

    Aim To study the chemical constituents of Euphorb/a ebracteolata Hayata. Methods Column chromatography was used in the isolation procedure, while the structures of isolated compounds were elucidated by spectral data. Results Six compounds were isolated and their structures were identified as baccatin (1), 3-acetyl-β-amyrin (2), 3,3'-diacetyl-4,4'-dim-ethoxy- 2,2', 6,6'-tetrah ydroxy diphenylmethane (3), 2,4- dihydroxy-6-methoxy-3-methyl acetophenone (4), β-sitosterol(5), and daucosterol (6). Conclusion Baccatin was obtained from Euphorbia ebracteolata for the first time.

  19. Chemical compass for bird navigation

    DEFF Research Database (Denmark)

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

    2014-01-01

    Migratory birds travel spectacular distances each year, navigating and orienting by a variety of means, most of which are poorly understood. Among them is a remarkable ability to perceive the intensity and direction of the Earth's magnetic field. Biologically credible mechanisms for the detection...... increased interest following the proposal in 2000 that free radical chemistry could occur in the bird's retina initiated by photoexcitation of cryptochrome, a specialized photoreceptor protein. In the present paper we review the important physical and chemical constraints on a possible radical...

  20. Chemical composition of interstellar dust

    Science.gov (United States)

    Das, Ankan; Chakrabarti, Sandip Kumar; Majumdar, Liton; Sahu, Dipen

    Study of chemical evolution of interstellar medium is well recognized to be a challenging task. Interstellar medium (ISM) is a rich reservoir of complex molecules. So far, around 180 gas phase molecules and around 20 molecular species on the interstellar dust have been detected in various regions of ISM, especially in regions of star formation. In last decade, it was well established that gas phase reactions alone cannot explain molecular abundances in ISM. Chemical reactions which occur on interstellar dust grains are essential to explain formation of several molecules especially hydrogenated species including simplest and most abundant molecule H2. Interstellar grains provide surface for accreted species to meet and react. Therefore, an understanding of formation of molecules on grain surfaces is of prime importance. We concentrate mainly on water, methanol, carbon dioxide, which constitute nearly 90% of the grain mantle. These molecules are detected on grain surface due to their strong absorption bands arising out of multiple vibrational modes. Water is the most abundant species (with a surface coverage >60% ) on a grain in dense interstellar medium. CO2 is second most abundant molecule in interstellar medium with an abundance of around 20% with respect to H2O. However, this can vary from cloud to cloud. In clouds like W 33A it could be even less than 5% of water abundance. The next most abundant molecule is CO, which is well studied ice with an abundance varying between 2%\\ to 15% of water. Methanol (CH3OH) is also very abundant having abundance 2% to 30% of water. Measurement of water deuterium fractionation is a relevant tool for understanding mechanisms of water formation and evolution from prestellar phase to formation of planets and comets. We are also considering deuterated species in our simulation. We use Monte Carlo method (considering multilayer regime) to mimic the exact scenario. We study chemical evolution of interstellar grain mantle by varying

  1. Constructivism, relativism, and chemical education.

    Science.gov (United States)

    Scerri, Eric

    2003-05-01

    Whereas most scientists are highly critical of constructivism and relativism in the context of scientific knowledge acquisition, the dominant school of chemical education researchers appears to support a variety of such positions. By reference to the views of Herron, Spencer, and Bodner, I claim that these authors are philosophically confused, and that they are presenting a damaging and anti-scientific message to other unsuspecting educators. Part of the problem, as I argue, is a failure to distinguish between pedagogical constructivism regarding students' understanding of science, and constructivism about the way that scientific knowledge is acquired by expert scientists.

  2. Chemical Engineering in the "BIO" world

    DEFF Research Database (Denmark)

    Chiarappa, Gianluca; Grassi, Mario; Abrami, Michela

    2017-01-01

    Modern Chemical Engineering was born around the end of the 19th century in Great Britain, Germany, and the USA, the most industrialized countries at that time. Milton C. Whitaker, in 1914, affirmed that the difference between Chemistry and Chemical Engineering lies in the capability of chemical e...

  3. Critical reflections on the Chemical Leasing concept

    NARCIS (Netherlands)

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

    2014-01-01

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

  4. 27 CFR 24.320 - Chemical record.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Chemical record. 24.320... OF THE TREASURY LIQUORS WINE Records and Reports § 24.320 Chemical record. A proprietor who uses chemicals, preservatives, or other such materials shall maintain a record of the purchase, receipt...

  5. Chemical experiment - the basis in learning chemistry

    Directory of Open Access Journals (Sweden)

    N. Dalabayeva

    2012-12-01

    Full Text Available Particular classification and method carrying out chemical experiment and their place in learning chemistry was considered. And also was showed that an application of kinds of chemical experiments competence develops in learning at the decision of experimental problems in chemistry. Features of solubility of firm substances in water are discussed at the chemical experiment and the process of dissolution.

  6. Chemical experiment - the basis in learning chemistry

    OpenAIRE

    N. Dalabayeva

    2012-01-01

    Particular classification and method carrying out chemical experiment and their place in learning chemistry was considered. And also was showed that an application of kinds of chemical experiments competence develops in learning at the decision of experimental problems in chemistry. Features of solubility of firm substances in water are discussed at the chemical experiment and the process of dissolution.

  7. Data Mining and Discovery of Chemical Knowledge

    Science.gov (United States)

    Wencong, Lu

    In this chapter, the Data mining methods adopted are briefly introduced. The main focuses are on the successful applications of data mining methods in chemistry and chemical engineering. The discoveries of chemical knowledge cover the formation of ternary Intermetallic compounds, structure activity relationships of drugs, and industrial optimization based on chemical data mining methods, especially by using statistical pattern recognition and support vector machine.

  8. Experiments To Demonstrate Chemical Process Safety Principles.

    Science.gov (United States)

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

    2001-01-01

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

  9. Experimental Demonstrations in Teaching Chemical Reactions.

    Science.gov (United States)

    Hugerat, Muhamad; Basheer, Sobhi

    2001-01-01

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

  10. The Second 50 Industrial Chemicals, Part 1.

    Science.gov (United States)

    Chenier, Philip J.; Artibee, Danette S.

    1988-01-01

    Provides an introduction to and summaries of the manufacturing methods and uses of chemicals 51-75 on the list of chemicals arranged in order of decreasing production in the United States. Gives production in pounds, annual growth, average price per pound, and organization according to the seven basic organic chemicals. (CW)

  11. Haz-Mat Refresher: Chemical Precautions

    Science.gov (United States)

    Caliendo, Louis A.

    2012-01-01

    It is important that first responders remain aware of the possible hazards resulting from chemical accidents or the intentional use of chemicals in destructive devices. Chemical components can be utilized in the manufacturing of improvised explosive devices (IEDs), can enhance the effect of a more conventional device, or can pose hazards based on…

  12. The chemical recycle of cotton

    Directory of Open Access Journals (Sweden)

    Alice Beyer Schuch

    2016-09-01

    Full Text Available The chemical recycle of cotton textiles and/or other cellulosic materials for the purpose of manufacturing regenerated high quality textiles fibres is a novel process. The objective of related research is based on the forecast of population growth, on resource scarcity predictions, and on the negative environmental impact of the textile industry. These facts lead the need of broadening the scope for long-term textile-to-textile recycle - as the mechanical recycle of natural fibres serve for limited number of cycles, still depends on input of virgin material, and offer a reduced-in-quality output. Critical analysis of scientific papers, relevant related reports, and personal interviews were the base of this study, which shows viable results in laboratorial scale of using low-quality cellulosic materials as input for the development of high-quality regenerated textile fibres though ecological chemical process. Nevertheless, to scale up and implement this innovative recycle method, other peripheral structures are requested, such as recover schemes or appropriate sort, for instance. Further researches should also be considered in regards to colours and impurities.

  13. Chemical food contaminants; Chemische Lebensmittelkontaminanten

    Energy Technology Data Exchange (ETDEWEB)

    Schrenk, D. [Technische Univ. Kaiserslautern (Germany)

    2004-09-15

    Chemical food contaminants are substances which are neither present naturally in the usual raw material used for food production nor are added during the regular production process. Examples are environmental pollutants or contaminants derived from agricultural production of crops or livestock or from inadequate manufacturing of the food product itself. More difficult is the classification of those compounds formed during regular manufacturing such as products of thermal processes including flavoring substances. In these cases, it is common practice to call those compounds contaminants which are known for their adverse effects such as acrylamide, whereas constituents which add to the food-specific flavor such as Maillard products formed during roasting, baking etc. are not termed contaminants. From a toxicological viewpoint this distinction is not always clear-cut. Important groups of chemical contaminants are metals such as mercury or lead, persistent organic pollutants such as polychlorinated biphenyls and related pollutants, which are regularly found in certain types of food originating from background levels of these compounds in our environment. Furthermore, natural toxins form microorganisms or plants, and compounds formed during thermal treatment of food are of major interest. In general, a scientific risk assessment has to be carried out for any known contaminant. This comprises an exposure analysis and a toxicological and epidemiological assessment. On these grounds, regulatory and/or technological measures can often improve the situation. Major conditions for a scientific risk assessment and a successful implementation of regulations are highly developed food quality control, food toxicology and nutritional epidemiology. (orig.)

  14. [Laboratory chemical analysis in ascites].

    Science.gov (United States)

    Satz, N

    1991-04-13

    Chemical analysis of ascitic fluid may be helpful in determining the underlying disease. We discuss the diagnostic accuracy of the common and newer chemical parameters (protein, LDH, lactate, glucose, cholesterol, triglycerides, phospholipids, fibronectin, albumin gradient [value of serum minus value of ascites], ferritin, tumor markers, immunomodulators, leukocytes, bacterial and cytologic examinations). We also review the pathogenesis and clinical findings of the most frequent ascites forms (benign hepatic, infective, malignant ascites, ascites associated with liver metastases or hepatocellular carcinoma, cardiac and pancreatic ascites) and the most important diagnosis criteria. In the malignant ascites a high cholesterol, a narrow albumin gradient or a high ferritin value have high diagnostic accuracy, but diagnosis is by the finding of malignant cells. For the diagnosis of infective ascites, bacteriology is mandatory even though the results are negative in most cases, particularly in spontaneous bacterial peritonitis where diagnosis has to be established clinically, by a low pH or by a high leukocyte count. Benign hepatic ascites is diagnosed by demonstrating an underlying chronic liver disease and laboratory examinations of the peritoneal fluid to exclude other causes. The laboratory tests in ascites associated with liver metastases or with hepatocellular carcinoma were similar to those in benign hepatic ascites and the two ascites forms must be separated by other clinical and technical findings. Pancreatic ascites can easily be distinguished from the other forms by the high amylase and lipase content.

  15. The Chemical Evolution of Phosphorus

    CERN Document Server

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

    2014-01-01

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

  16. Chemical leukoderma induced by dimethyl sulfate*

    Science.gov (United States)

    Gozali, Maya Valeska; Zhang, Jia-an; Yi, Fei; Zhou, Bing-rong; Luo, Dan

    2016-01-01

    Chemical leukoderma occurs due to the toxic effect of a variety of chemical agents. Mechanisms include either destruction or inhibition of melanocytes. We report two male patients (36 and 51 years old) who presented with multiple hypopigmented macules and patches on the neck, wrist, and legs after exposure to dimethyl sulfate in a chemical industry. Physical examination revealed irregular depigmentation macules with sharp edges and clear hyperpigmentation around the lesions. History of repeated exposure to a chemical agent can help the clinical diagnosis of chemical leukoderma. This diagnosis is very important for prognosis and therapeutic management of the disease.

  17. Fixed Points for Stochastic Open Chemical Systems

    CERN Document Server

    Malyshev, V A

    2011-01-01

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

  18. Assessment of chemicals in construction products

    DEFF Research Database (Denmark)

    Krogh, Hanne; Olsen, Stig Irving

    2000-01-01

    The building sector uses a lot of products (several thousands) and many of these contain chemicals, some of which have harmful effects on human and environmental health. Due to the restricted knowledge of data, the impacts of chemicals can be overlooked e.g. in eco-profiles of building elements....... The reasons for that are lacks of product-specific emissions by manufacturing of chemical products, e.g. waterproofing systems and sealants. Besides, most LCA-models do not include assessments of emissions in working environment, in indoor environment or from disposal processes. It was therefore...... in the project Assessment of Chemicals in Construction Products decided to adapt an existing score method for assessing the chemicals. As the European countries had agreed on a score Method for Risk Ranking chemicals (EURAM), it was decided to use this method to assess chemicals in construction products for two...

  19. Predictive toxicology of chemicals and database mining

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  20. Chemical reactions at aqueous interfaces

    Science.gov (United States)

    Vecitis, Chad David

    2009-12-01

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

  1. The problem of current toxic chemicals management.

    Science.gov (United States)

    Tickner, Joel; Geiser, Ken

    2004-01-01

    In this article, we explore the limitations of current chemicals management policies worldwide and the evolution of new European, International and U.S. policies to address the problem of toxic chemicals control. It is becoming increasingly apparent that current chemicals management policies in Europe and the United States are inadequate. There is a general lack of toxicity and exposure information on chemicals in commerce and the vast majority of chemicals were considered safe until proven guilty in legislation. Governments must then prove each chemical is dangerous through a slow and resource-intensive risk assessment process. For more than a decade, Nordic countries, such as Denmark and Sweden, have actively promoted integrated chemicals policies to address contamination of critical waterways. They have successfully used a variety of voluntary and mandatory policy tools, such as education, procurement, lists of chemicals of concern, eco-labeling, research and development on safer substitutes, and chemical phase-out requirements, to encourage companies using chemicals to reduce their reliance on harmful substances and to develop safer substitutes. While previously isolated to particular countries, innovative and exciting European-wide policies to promote sustainable chemicals management are now moving forward, including the recently published draft Registration, Evaluation and Authorization of CHemicals (REACH) policy of the European Union. A sweeping change in chemicals management policies in Europe is inevitable and it will ultimately affect manufacturers in the U.S. and globally. The European movement provides an opportunity to initiate a discussion on integrated chemicals policy in the U.S. where some innovative initiatives already are underway.

  2. Chemical experiment through the microscope. II. ; Chemical garden. Kenbikyo wo shiyoshita kagaku jikken. II. ; Chemical garden

    Energy Technology Data Exchange (ETDEWEB)

    Ninomiya, A.

    1991-06-10

    This report describes the result of observation on chemical garden through the microscope. After putting some 2-3ml sodium silicate solution with fixed concentration into a cistern made of acrylic, various kinds of metallic salt with crystal size smaller than 2mm are added. The cistern is then placed on the stage of the microscope at an angle of 30{degree} to investigate buds growing from crystals of metallic salt specimens. Adopted concentrations of sodium silicate solution are 5%, 20%, and 50%. As a result, at the tips of growing buds, active motions of buds and increase of silicate in each kind of metal as reactive product are observed. In general, silicate concentration in the same metal increases conspicuously with lower concentration of sodium silicate solution. Moreover, it can be considered that the reason why chemical garden can be observed is not only because of difference in water pressure but also an important factor, the thickness of membranes at the tips of buds. 6 refs., 12 figs.

  3. Chemical modeling of exoplanet atmospheres

    CERN Document Server

    Venot, Olivia

    2014-01-01

    The past twenty years have revealed the diversity of planets that exist in the Universe. It turned out that most of exoplanets are different from the planets of our Solar System and thus, everything about them needs to be explored. Thanks to current observational technologies, we are able to determine some information about the atmospheric composition, the thermal structure and the dynamics of these exoplanets, but many questions remain still unanswered. To improve our knowledge about exoplanetary systems, more accurate observations are needed and that is why the Exoplanet Characterisation Observatory (EChO) is an essential space mission. Thanks to its large spectral coverage and high spectral resolution, EChO will provide exoplanetary spectra with an unprecedented accuracy, allowing to improve our understanding of exoplanets. In this work, we review what has been done to date concerning the chemical modeling of exoplanet atmospheres and what are the main characteristics of warm exoplanet atmospheres, which a...

  4. Information Extraction From Chemical Patents

    Directory of Open Access Journals (Sweden)

    Sandra Bergmann

    2012-01-01

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

  5. Chemical control of flowering time

    DEFF Research Database (Denmark)

    Ionescu, Irina Alexandra; Møller, Birger Lindberg; Sánchez Pérez, Raquel

    2017-01-01

    the transition to flowering as well as flower opening. Increased emphasis on research within this area has the potential to counteract the negative effects of global warming on flowering time, especially in perennial crop plants. Perennial crops have a requirement for winter chill, but winters become...... increasingly warm in temperate regions. This has dramatic effects on crop yield. Different strategies are therefore being developed to engineer flowering time to match local growing conditions. The majority of these efforts are within plant breeding, which benefits from a substantial amount of knowledge...... on the genetic aspects of flowering time regulation in annuals, but less so in perennials. An alternative to plant breeding approaches is to engineer flowering time chemically via the external application of flower-inducing compounds. This review discusses a variety of exogenously applied compounds used in fruit...

  6. Chemical evolution of star clusters

    CERN Document Server

    van Loon, Jacco Th

    2009-01-01

    I discuss the chemical evolution of star clusters, with emphasis on old globular clusters, in relation to their formation histories. Globular clusters clearly formed in a complex fashion, under markedly different conditions from any younger clusters presently known. Those special conditions must be linked to the early formation epoch of the Galaxy and must not have occurred since. While a link to the formation of globular clusters in dwarf galaxies has been suggested, present-day dwarf galaxies are not representative of the gravitational potential wells within which the globular clusters formed. Instead, a formation deep within the proto-Galaxy or within dark-matter minihaloes might be favoured. Not all globular clusters may have formed and evolved similarly. In particular, we may need to distinguish Galactic halo from Galactic bulge clusters.

  7. Chemical evolution of star clusters.

    Science.gov (United States)

    van Loon, Jacco Th

    2010-02-28

    I discuss the chemical evolution of star clusters, with emphasis on old Galactic globular clusters (GCs), in relation to their formation histories. GCs are clearly formed in a complex fashion, under markedly different conditions from any younger clusters presently known. Those special conditions must be linked to the early formation epoch of the Galaxy and must not have occurred since. While a link to the formation of GCs in dwarf galaxies has been suggested, present-day dwarf galaxies are not representative of the gravitational potential wells within which the GCs formed. Instead, a formation deep within the proto-Galaxy or within dark-matter mini-haloes might be favoured. Not all GCs may have formed and evolved similarly. In particular, we may need to distinguish Galactic Halo from Galactic Bulge clusters.

  8. Olefin Metathesis for Chemical Biology

    Science.gov (United States)

    Binder, Joseph B; Raines, Ronald T

    2009-01-01

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

  9. Coacervates as prebiotic chemical reactors

    Science.gov (United States)

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

    2012-10-01

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

  10. Oscillations of a chemical garden

    Science.gov (United States)

    Pantaleone, J.; Toth, A.; Horvath, D.; Rother McMahan, J.; Smith, R.; Butki, D.; Braden, J.; Mathews, E.; Geri, H.; Maselko, J.

    2008-04-01

    When soluble metal salts are placed in a silicate solution, chemical gardens grow. These gardens are treelike structures formed of long, thin, hollow tubes. Here we study one particular case: a calcium nitrate pellet in a solution of sodium trisilicate. We observe that tube growth results from a relaxation oscillation. The average period and the average growth rate are approximately constant for most of the structures growth. The period does fluctuate from cycle to cycle, with the oscillation amplitude proportional to the period. Based on our observations, we develop a model of the relaxation oscillations which calculates the average oscillation period and the average tube radius in terms of fundamental membrane parameters. We also propose a model for the average tube growth rate. Predictions are made for future experiments.

  11. [Risk assessment of chemical agents].

    Science.gov (United States)

    Cottica, Danilo; Grignani, Elena; Bartolucci, Giovanni Battista

    2011-01-01

    The risk assessment of chemical agents is a well known and applied process carried out by Industrial Hygienists and Occupational Physicians based on exposure evaluation. The application of REACH (CE 1907/2006), CLP (CE 1272/2008) and SDS (UE 453/2010) introduces some changes and instruments to carry out the occupational exposure assessment, like new classification of substances, Exposure Scenario, suggested control measures that the Industrial Hygienist and the Occupational Physician must evaluate. If there is not a similar Exposure Scenario to apply a new risk assessment must carried out also by recommended software (ECETOC Targeted Risk Assessment; Easy to use workplace EMKG; Stoffenmanager). Looking at the relevance of the control measures and evaluation of Exposure Scenario we report the flowchart of risk assessment and management by the Method of Organisational Congruencies carried out with the Prevention and Protection Service and Occupational Physician Office of the Health Service of the Azienda Provinciale of Trento.

  12. Tungsten chemical vapor deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Kiichi; Takeda, Nobuo.

    1993-07-13

    A tungsten chemical vapor deposition method is described, comprising: a first step of selectively growing a first thin tungsten film of a predetermined thickness in a desired region on the surface of a silicon substrate by reduction of a WF[sub 6] gas introduced into an atmosphere of a predetermined temperature containing said silicon substrate; and a second step of selectively growing a second tungsten film of a predetermined thickness on said first thin tungsten film by reduction of said WF[sub 6] with a silane gas further introduced into said atmosphere, wherein the surface state of said substrate is monitored by a pyrometer and the switching from said first step to said second step is performed when the emissivity of infrared light from the substrate surfaces reaches a predetermined value.

  13. Structure validation in chemical crystallography.

    Science.gov (United States)

    Spek, Anthony L

    2009-02-01

    Automated structure validation was introduced in chemical crystallography about 12 years ago as a tool to assist practitioners with the exponential growth in crystal structure analyses. Validation has since evolved into an easy-to-use checkCIF/PLATON web-based IUCr service. The result of a crystal structure determination has to be supplied as a CIF-formatted computer-readable file. The checking software tests the data in the CIF for completeness, quality and consistency. In addition, the reported structure is checked for incomplete analysis, errors in the analysis and relevant issues to be verified. A validation report is generated in the form of a list of ALERTS on the issues to be corrected, checked or commented on. Structure validation has largely eliminated obvious problems with structure reports published in IUCr journals, such as refinement in a space group of too low symmetry. This paper reports on the current status of structure validation and possible future extensions.

  14. Polyfluorinated chemicals and transformation products

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

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

  15. The Ocular Surface Chemical Burns

    Directory of Open Access Journals (Sweden)

    Medi Eslani

    2014-01-01

    Full Text Available Ocular chemical burns are common and serious ocular emergencies that require immediate and intensive evaluation and care. The victims of such incidents are usually young, and therefore loss of vision and disfigurement could dramatically affect their lives. The clinical course can be divided into immediate, acute, early, and late reparative phases. The degree of limbal, corneal, and conjunctival involvement at the time of injury is critically associated with prognosis. The treatment starts with simple but vision saving steps and is continued with complicated surgical procedures later in the course of the disease. The goal of treatment is to restore the normal ocular surface anatomy and function. Limbal stem cell transplantation, amniotic membrane transplantation, and ultimately keratoprosthesis may be indicated depending on the patients’ needs.

  16. Thin films under chemical stress

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

  17. Chemical avoidance responses of fishes.

    Science.gov (United States)

    Tierney, Keith B

    2016-05-01

    The hydrosphere is a repository for all of our waste and mistakes, be they sewage, garbage, process-affected waters, runoff, and gases. For fish living in environments receiving undesirable inputs, moving away seems an obvious way to avoid harm. While this should occur, there are numerous examples where it will not. The inability to avoid harmful environments may lead to sensory impairments that in turn limit the ability to avoid other dangers or locate benefits. For avoidance to occur, the danger must first be perceived, which may not happen if the fish is 'blinded' in some capacity. Second, the danger must be recognized for what it is, which may also not happen if the fish is cognitively confused or impaired. Third, it is possible that the fish may not be able to leave the area, or worse, learns to prefer a toxic environment. Concerning generating regulations around avoidance, there are two possibilities: that an avoidance threshold be used to set guidelines for effluent release with the intention of driving fishes away; the second is to set a contaminant concentration that would not affect the avoidance or attraction responses to other cues. With the complexities of the modern world in which we release diverse pollutants, from light to municipal effluents full of 1000s of chemicals, to the diversity present in ecosystems, it is impossible to have avoidance data on every stimulus-species combination. Nevertheless, we may be able to use existing avoidance response data to predict the likelihood of avoidance of untested stimuli. Where we cannot, this review includes a framework that can be used to direct new research. This review is intended to collate existing avoidance response data, provide a framework for making decisions in the absence of data, and suggest studies that would facilitate the prediction of risk to fish health in environments receiving intentional and unintentional human-based chemical inputs.

  18. Chemical contamination of water supplies

    Energy Technology Data Exchange (ETDEWEB)

    Shy, C.M.

    1985-10-01

    Man-made organic chemicals have been found in drinking water for many years. Their numbers and varieties increase as our analytical capabilities improve. The identified chemicals comprise 10 to 20% of the total organic matter present. These are volatile or low molecular weight compounds which are easily identified. Many of them are carcinogenic or mutagenic. Chlorinated compounds have been found in untreated well water at levels up to 21,300 micrograms/L and are generally present at higher levels in chlorine-treated water than in untreated water. Aggregate risk studies for cancer are summarized. The most common sites are: bladder, stomach, colon, and rectum. Such studies cannot be linked to individual cases. However, they are useful for identifying exposed populations for epidemiologic studies. Five case-control studies were reviewed, and significant associations with water quality were found for: bladder cancer in two studies, colon cancer in three and rectal cancer in four. A large study by the National Cancer Institute found that there had been a change in the source of raw water for 50% of the persons in one area between the years 1955 and 1975. Such flaws in the data may preclude finding a causal relation between cancer and contaminants in drinking water. Large case-control and cohort studies are needed because of the low frequency of the marker diseases, bladder and rectal cancer. Cohort studies may be precluded by variations in the kinds of water contaminants. Definitive questions about these issues are posed for cooperative effort and resolution by water chemists, engineers, and epidemiologists.

  19. Chemical Reactivity as Described by Quantum Chemical Methods

    Directory of Open Access Journals (Sweden)

    F. De Proft

    2002-04-01

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

  20. Electrostatic thin film chemical and biological sensor

    Science.gov (United States)

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

    2010-01-19

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

  1. Toxic chemical considerations for tank farm releases

    Energy Technology Data Exchange (ETDEWEB)

    Van Keuren, J.C.; Davis, J.S., Westinghouse Hanford

    1996-08-01

    This topical report contains technical information used to determine the accident consequences of releases of toxic chemical and gases for the Tank Farm Final Safety Analysis report (FSAR).It does not provide results for specific accident scenarios but does provide information for use in those calculations including chemicals to be considered, chemical concentrations, chemical limits and a method of summing the fractional contributions of each chemical. Tank farm composites evaluated were liquids and solids for double shell tanks, single shell tanks, all solids,all liquids, headspace gases, and 241-C-106 solids. Emergency response planning guidelines (ERPGs) were used as the limits.Where ERPGs were not available for the chemicals of interest, surrogate ERPGs were developed. Revision 2 includes updated sample data, an executive summary, and some editorial revisions.

  2. Ending the scourge of chemical weapons

    Energy Technology Data Exchange (ETDEWEB)

    Brin, J.

    1993-04-01

    After more than 20 years of arduous negotiations, representatives from 131 countries gathered in Paris in January to sign a treaty banning the development, production, and transfer to other countries of chemical-warfare agents and their means of delivery. The treaty - called the Chemical Weapons Convention, or CWC - complements the more limited Geneva Protocol of 1925, which bans the use of toxic chemicals in warfare. When the CWC enters into force in about two years, it will prohibit the manufacture for military purposes of lethal chemicals such as sulfur mustard, which causes painful skin blistering and lung damage, and nerve agents, which cause rapid death by interfering with the transmission of nerve impulses. The goal is to eliminate from the earth this particularly inhumane form of warfare. The paper discusses facets of the treaty, especially the verification challenge with its inspection on demand features. Short accompanying pieces discuss classifying chemicals and the destruction of chemical weapons under the CWC.

  3. New Thermodynamic Paradigm of Chemical Equilibria

    CERN Document Server

    Zilbergleyt, B

    2011-01-01

    The paper presents new thermodynamic paradigm of chemical equilibrium, setting forth comprehensive basics of Discrete Thermodynamics of Chemical Equilibria (DTd). Along with previous results by the author during the last decade, this work contains also some new developments of DTd. Based on the Onsager's constitutive equations, reformulated by the author thermodynamic affinity and reaction extent, and Le Chatelier's principle, DTd brings forward a notion of chemical equilibrium as a balance of internal and external thermodynamic forces (TdF), acting against a chemical system. Basic expression of DTd is the chemical system logistic map of thermodynamic states that ties together energetic characteristics of chemical reaction, occurring in the system, the system shift from "true" thermodynamic equilibrium (TdE), and causing that shift external thermodynamic forces. Solutions to the basic map are pitchfork bifurcation diagrams in coordinates "shift from TdE - growth factor (or TdF)"; points, corresponding to the ...

  4. Modular Chemical Descriptor Language (MCDL: Stereochemical modules

    Directory of Open Access Journals (Sweden)

    Gakh Andrei A

    2011-01-01

    Full Text Available Abstract Background In our previous papers we introduced the Modular Chemical Descriptor Language (MCDL for providing a linear representation of chemical information. A subsequent development was the MCDL Java Chemical Structure Editor which is capable of drawing chemical structures from linear representations and generating MCDL descriptors from structures. Results In this paper we present MCDL modules and accompanying software that incorporate unique representation of molecular stereochemistry based on Cahn-Ingold-Prelog and Fischer ideas in constructing stereoisomer descriptors. The paper also contains additional discussions regarding canonical representation of stereochemical isomers, and brief algorithm descriptions of the open source LINDES, Java applet, and Open Babel MCDL processing module software packages. Conclusions Testing of the upgraded MCDL Java Chemical Structure Editor on compounds taken from several large and diverse chemical databases demonstrated satisfactory performance for storage and processing of stereochemical information in MCDL format.

  5. Exploring the planetary boundary for chemical pollution

    DEFF Research Database (Denmark)

    Diamond, Miriam L.; de Wit, Cynthia A.; Molander, Sverker

    2015-01-01

    Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if "unacceptable global change" is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience...... of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales......, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient...

  6. QCD Phase Diagram with Imaginary Chemical Potential

    Directory of Open Access Journals (Sweden)

    Nakamura Atsushi

    2012-02-01

    Full Text Available We report our recent results on the QCD phase diagram obtained from the lattice QCD simulation. The location of the phase boundary between hadronic and QGP phases in the two-flavor QCD phase diagram is investigated. The imaginary chemical potential approach is employed, which is based on Monte Carlo simulations of the QCD with imaginary chemical potential and analytic continuation to the real chemical potential region.

  7. Endocrine Disrupting Chemicals and Disease Susceptibility

    OpenAIRE

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

    2011-01-01

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

  8. Sustainable Development in Chemical Fiber Industry

    Institute of Scientific and Technical Information of China (English)

    Flora Zhao

    2012-01-01

    The 18th China International Man-Made Fiber Conference (Xiaoshan 2012), themed on "How does Chemical Fiber Industry to Realize Sustainable Development against the Background of High-cost Era?", kicked off in Hangzhou on September 6th, 2012. More than 600 representatives from nearly 20 major chemical fiber manufacturing countries and regions all over the world were gathered together to discuss the sustainable development strategies of international chemical fiber industry in the context of the current compficated environment from different perspectives.

  9. Flavour chemicals in electronic cigarette fluids

    OpenAIRE

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

    2015-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  11. Chemical Carcinogenesis Research Information System (CCRIS)

    Data.gov (United States)

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

  12. Ecological optimization of endoreversible chemical engines

    Directory of Open Access Journals (Sweden)

    Dan Xia, Lingen Chen, Fengrui Sun

    2011-09-01

    Full Text Available Optimal ecological performances of endoreversible chemical engine cycles with both linear and diffusive mass transfer laws are derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the power output and entropy production rate of the chemical engines. Numerical examples are given to show the effects of mass-reservoir chemical potential ratio and mass-transfer coefficient ratio on the ecological function versus the efficiency characteristic of the cycles. The results can provide some theoretical guidelines for the design of practical chemical engines.

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

    Directory of Open Access Journals (Sweden)

    Bajaj A

    2010-01-01

    Full Text Available Chemical leucoderma is an industrial disorder in developed countries and the common causative chemicals are phenols and catechols. Due to stringent controls and preventive measures the incidence has come down. In the recent past various chemicals in consumer products have also been documented to produce depigmentation.In India due to lax quality control measures chemical leucoderma due to consumer items is not uncommon.The various consumer items documented to cause contact depigmentation are sticker bindis,rain shoes,plastic chappals,hair dye/ black henna( kali mehndi, alta, wallets and even mobile plastic covers.

  14. Overall view of chemical and biochemical weapons.

    Science.gov (United States)

    Pitschmann, Vladimír

    2014-06-04

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

  15. Overall View of Chemical and Biochemical Weapons

    Directory of Open Access Journals (Sweden)

    Vladimír Pitschmann

    2014-06-01

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

  16. Chemical Implementation of Finite-State Machines

    Science.gov (United States)

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

    1992-01-01

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

  17. Biology Today. Thinking Chemically about Biology.

    Science.gov (United States)

    Flannery, Maura C.

    1990-01-01

    Discussed are applications of biochemistry. Included are designed drugs, clever drugs, carcinogenic structures, sugary wine, caged chemicals, biomaterials, marine chemistry, biopolymers, prospecting bacteria, and plant chemistry. (CW)

  18. Linking algal growth inhibition to chemical activity

    DEFF Research Database (Denmark)

    Schmidt, Stine N.; Mayer, Philipp

    to chemical activity, as opposed to e.g. the total concentration. Baseline toxicity (narcosis) for neutral hydrophobic organic compounds has been shown to initiate in the narrow chemical activity range of 0.01 to 0.1. This presentation focuses on linking algal growth inhibition to chemical activity....... High-quality toxicity data are carefully selected from peer-reviewed scientific literature and QSAR databases. This presentation shows how the chemical activity concept can be used to compare and combine toxicity data across compounds and species in order to characterize toxicity – and further how...

  19. Hazardous chemical tracking system (HAZ-TRAC)

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-07-01

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

  20. Hemolytic anemia caused by chemicals and toxins

    Science.gov (United States)

    ... This list is not all-inclusive. Alternative Names Anemia - hemolytic - caused by chemicals or toxins References Michel M. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Schafer ...

  1. Chemical Measurement and Fluctuation Scaling.

    Science.gov (United States)

    Hanley, Quentin S

    2016-12-20

    Fluctuation scaling reports on all processes producing a data set. Some fluctuation scaling relationships, such as the Horwitz curve, follow exponential dispersion models which have useful properties. The mean-variance method applied to Poisson distributed data is a special case of these properties allowing the gain of a system to be measured. Here, a general method is described for investigating gain (G), dispersion (β), and process (α) in any system whose fluctuation scaling follows a simple exponential dispersion model, a segmented exponential dispersion model, or complex scaling following such a model locally. When gain and dispersion cannot be obtained directly, relative parameters, GR and βR, may be used. The method was demonstrated on data sets conforming to simple, segmented, and complex scaling. These included mass, fluorescence intensity, and absorbance measurements and specifications for classes of calibration weights. Changes in gain, dispersion, and process were observed in the scaling of these data sets in response to instrument parameters, photon fluxes, mathematical processing, and calibration weight class. The process parameter which limits the type of statistical process that can be invoked to explain a data set typically exhibited 0 4 possible. With two exceptions, calibration weight class definitions only affected β. Adjusting photomultiplier voltage while measuring fluorescence intensity changed all three parameters (0 < α < 0.8; 0 < βR < 3; 0 < GR < 4.1). The method provides a framework for calibrating and interpreting uncertainty in chemical measurement allowing robust comparison of specific instruments, conditions, and methods.

  2. 2005 Chemical Reactions at Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cynthia M. Friend

    2006-03-14

    The Gordon Research Conference (GRC) on 2005 Chemical Reactions at Surfaces was held at Ventura Beach Marriott, Ventura California from February 13, 2005 through February 18, 2005. The Conference was well-attended with 124 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions. In order that more scientists could communicate their most recent results, poster presentation time was scheduled. Attached is a copy of the formal schedule and speaker program and the poster program. In addition to these formal interactions, 'free time' was scheduled to allow informal discussions. Such discussions are fostering new collaborations and joint efforts in the field.

  3. [Chemical constituents of Poria cocos].

    Science.gov (United States)

    Yang, Peng-Fei; Liu, Chao; Wang, Hong-Qing; Li, Jia-Chun; Wang, Zhen-Zhong; Xiao, Wei; Chen, Ruo-Yun

    2014-03-01

    The chemical constituents of Poria cocos were studied by means of silica gel, ODS column chromatography, Sephadex LH-20 and preparative HPLC. Thirteen compounds were isolated from this plant. By analysis of the ESI-MS and NMR data, the structures of these compounds were determined as tumulosic acid (1), dehydrotumulosic acid (2), 3beta, 5alpha-dihydroxy-ergosta-7, 22-dien-6-one (3), 3beta, 5alpha, 9alpha-trihydroxy-ergosta-7, 22-diene -6-one (4), ergosta-7, 22-diene-3-one (5), 6, 9-epoxy-ergosta-7,22-diene-3-ol (6), ergosta-4,22-diene-3-one (7), 3beta, 5alpha, 6beta-trihydroxyl-ergosta-7,22-diene (8), ergosta-5, 6-epoxy-7,22-dien-3-ol (9), beta-sitosterol (10), ribitol (11), mannitol (12), and oleanic acid 3-O-acetate (13), respectively. Compounds 3-13 were isolated from the P. cocos for the first time.

  4. Origin of Cosmic Chemical Abundances

    CERN Document Server

    Maio, Umberto

    2015-01-01

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

  5. Arrays of coupled chemical oscillators

    CERN Document Server

    Forrester, Derek Michael

    2016-01-01

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

  6. Inorganic chemically active adsorbents (ICAAs)

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

  7. Bimatoprost-induced chemical blepharoplasty.

    Science.gov (United States)

    Sarnoff, Deborah S; Gotkin, Robert H

    2015-05-01

    We report significant changes in the appearance of the periorbital area, beyond eyelash enhancement, induced by the topical application of bimatoprost ophthalmic solution, 0.03% (Latisse®, Allergan, Inc., Irvine, CA). To our knowledge, this is the first report in the dermatology or plastic surgery literature describing the rejuvenating effect and overall improvement in the appearance of the periorbital area resulting from applying Latisse to the upper eyelid margins. To date, reports in the literature discuss side-effects and potential complications of topical bimatoprost therapy causing a constellation of findings known as PAP (prostaglandin-associated periorbitopathy). While periorbitopathy implies pathology or a state of disease, we report changes that can be perceived as an improvement in the overall appearance of the periorbital area. We, therefore, propose a name change from PAP to PAPS - prostaglandin- associated periorbital syndrome. This better describes the beneficial, as well as the possible negative effects of topical bimatoprost. Although there is a risk for periorbital disfigurement, when used bilaterally, in properly selected candidates and titrated appropriately, bimatoprost can be beneficial. The striking improvement in the appearance of some individuals warrants further research into the potential use of topical bimatoprost to achieve a "chemical blepharoplasty."

  8. Chemical constituents of Cinnamomum cebuense

    Institute of Scientific and Technical Information of China (English)

    Consolacion Y.Ragasa; Dinah L.Espineli; Esperanza Maribel G.Agoo; Ramon S.del Fierro

    2013-01-01

    AIM:To investigate the chemical constituents of Cinnamomum cebuense,an endemic and critically endangered tree found only in Cebu,Philippines.METHODS:The compounds were isolated by silica gel chromatography.The structures of the isolates were elucidated by NMR spectroscopy.RESULTS:The dichloromethane (DCM) extract of the bark of C.cebuense afforded a new monoterpene natural product 1 and a new sesquiterpene 2,along with the known compounds,4-hydroxy-3-methoxycinnamaldehyde (3),4-allyl-2-methoxyphenol (4),α-terpineol (5) and humulene (6).The DCM extract of the leaves of C.cebuense yielded 6,β-caryophyllene (7),squalene (8),and a mixture of α-amyrin (9),β-amyrin (10) and bauerenol (11).The structures of 1-7 were elucidated by extensive 1D and 2D NMR spectroscopy,while the structures of 8-11 were identified by comparison of their 13C NMR data with those reported in the literature.CONCLUSION:The bark of C.cebuense afforded monoterpenes,sesquiterpenes and phenolics,while the leaves yielded sesquiterpenes and triterpenes.

  9. Chemical theory of dislocation mobility

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, J.J. [Materials Science and Engineering, University of California at Los Angeles, Los Angeles, CA 90095 (United States)]. E-mail: gilman@seas.ucla.edu

    2005-11-15

    Crystal dislocations were invented (circa. 1930) to explain why pure metal crystals are soft compared with homogeneous shear strengths calculated from atomic theory. They do this very well. However, later (circa. 1945) it was found that pure semiconductor crystals (e.g., Ge and Si) have hardnesses at room temperature comparable with calculated homogeneous shear strengths. Furthermore, it was known that pure metal-metalloid crystals (e.g., TiC and WC) are very hard, although they conduct electricity like metals. How can these differences be explained? The differences just outlined cannot be explained by means of a classical mechanical model. However, they can be explained by considering the chemical bonding in differing solid crystals. In particular, hardness depends on the degree of localization of the valence (bonding) electrons. Qualitatively, this is a very old idea. What is new is that it is possible to provide quantitative theories by using the results of quantum chemistry, and relatively simple analysis. Selected sets of crystal types must be treated, of course, just as selected sets of molecules are treated in theoretical chemistry. Otherwise the rationalization becomes unmanageable.

  10. Chemical experiments with superheavy elements.

    Science.gov (United States)

    Türler, Andreas

    2010-01-01

    Unnoticed by many chemists, the Periodic Table of the Elements has been extended significantly in the last couple of years and the 7th period has very recently been completed with eka-Rn (element 118) currently being the heaviest element whose synthesis has been reported. These 'superheavy' elements (also called transactinides with atomic number > or = 104 (Rf)) have been artificially synthesized in fusion reactions at accelerators in minute quantities of a few single atoms. In addition, all isotopes of the transactinide elements are radioactive and decay with rather short half-lives. Nevertheless, it has been possible in some cases to investigate experimentally chemical properties of transactinide elements and even synthesize simple compounds. The experimental investigation of superheavy elements is especially intriguing, since theoretical calculations predict significant deviations from periodic trends due to the influence of strong relativistic effects. In this contribution first experiments with hassium (Hs, atomic number 108), copernicium (Cn, atomic number 112) and element 114 (eka-Pb) are reviewed.

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

    Science.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    PHELAN, JAMES M.

    2002-05-01

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

  13. 46 CFR 154.1150 - Distribution of dry chemical.

    Science.gov (United States)

    2010-10-01

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

  14. Multimedia environmental chemical partitioning from molecular information.

    Science.gov (United States)

    Martínez, Izacar; Grifoll, Jordi; Giralt, Francesc; Rallo, Robert

    2010-12-15

    The prospect of assessing the environmental distribution of chemicals directly from their molecular information was analyzed. Multimedia chemical partitioning of 455 chemicals, expressed in dimensionless compartmental mass ratios, was predicted by SimpleBox 3, a Level III Fugacity model, together with the propagation of reported uncertainty for key physicochemical and transport properties, and degradation rates. Chemicals, some registered in priority lists, were selected according to the availability of experimental property data to minimize the influence of predicted information in model development. Chemicals were emitted in air or water in a fixed geographical scenario representing the Netherlands and characterized by five compartments (air, water, sediments, soil and vegetation). Quantitative structure-fate relationship (QSFR) models to predict mass ratios in different compartments were developed with support vector regression algorithms. A set of molecular descriptors, including the molecular weight and 38 counts of molecular constituents were adopted to characterize the chemical space. Out of the 455 chemicals, 375 were used for training and testing the QSFR models, while 80 were excluded from model development and were used as an external validation set. Training and test chemicals were selected and the domain of applicability (DOA) of the QSFRs established by means of self-organizing maps according to structural similarity. Best results were obtained with QSFR models developed for chemicals belonging to either the class [C] and [C; O], or the class with at least one heteroatom different than oxygen in the structure. These two class-specific models, with respectively 146 and 229 chemicals, showed a predictive squared coefficient of q(2) ≥ 0.90 both for air and water, which respectively dropped to q(2)≈ 0.70 and 0.40 for outlying chemicals. Prediction errors were of the same order of magnitude as the deviations associated to the uncertainty of the

  15. Empirical isotropic chemical shift surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Czinki, Eszter; Csaszar, Attila G. [Eoetvoes University, Laboratory of Molecular Spectroscopy, Institute of Chemistry (Hungary)], E-mail: csaszar@chem.elte.hu

    2007-08-15

    A list of proteins is given for which spatial structures, with a resolution better than 2.5 A, are known from entries in the Protein Data Bank (PDB) and isotropic chemical shift (ICS) values are known from the RefDB database related to the Biological Magnetic Resonance Bank (BMRB) database. The structures chosen provide, with unknown uncertainties, dihedral angles {phi} and {psi} characterizing the backbone structure of the residues. The joint use of experimental ICSs of the same residues within the proteins, again with mostly unknown uncertainties, and ab initio ICS({phi},{psi}) surfaces obtained for the model peptides For-(l-Ala){sub n}-NH{sub 2}, with n = 1, 3, and 5, resulted in so-called empirical ICS({phi},{psi}) surfaces for all major nuclei of the 20 naturally occurring {alpha}-amino acids. Out of the many empirical surfaces determined, it is the 13C{sup {alpha}} ICS({phi},{psi}) surface which seems to be most promising for identifying major secondary structure types, {alpha}-helix, {beta}-strand, left-handed helix ({alpha}{sub D}), and polyproline-II. Detailed tests suggest that Ala is a good model for many naturally occurring {alpha}-amino acids. Two-dimensional empirical 13C{sup {alpha}}-{sup 1}H{sup {alpha}} ICS({phi},{psi}) correlation plots, obtained so far only from computations on small peptide models, suggest the utility of the experimental information contained therein and thus they should provide useful constraints for structure determinations of proteins.

  16. Chemical compatibility screening test results

    Energy Technology Data Exchange (ETDEWEB)

    Nigrey, P.J.; Dickens, T.G.

    1997-12-01

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

  17. Chemical Biodynamics Division. Annual report 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

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

  18. Quantum chemical studies of estrogenic compounds

    Science.gov (United States)

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

  19. Valence-Bond Theory and Chemical Structure.

    Science.gov (United States)

    Klein, Douglas J.; Trinajstic, Nenad

    1990-01-01

    Discussed is the importance of valence bond theory on the quantum-mechanical theory of chemical structure and the nature of the chemical bond. Described briefly are early VB theory, development of VB theory, modern versions, solid-state applications, models, treatment in textbooks, and flaws in criticisms of valence bond theory. (KR)

  20. Innovations Help Chemical Makers Improve Growing Potential

    Institute of Scientific and Technical Information of China (English)

    Zhong Weike

    2007-01-01

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

  1. Mixture toxicity of PBT-like chemicals

    DEFF Research Database (Denmark)

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

    beyond that of the individual components. Firstly, the effects of three chemicals with PBT-like properties (acetyl cedrene, pyrene and triclosan) was examined on the freshwater snail, Potamopyrgus antipodarum. Secondly, mixture bioaccumulation of the same three chemicals were assessed experimentally...

  2. Heat Exchanger Lab for Chemical Engineering Undergraduates

    Science.gov (United States)

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

    2015-01-01

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

  3. Chemical labeling of electrochemically cleaved peptides

    NARCIS (Netherlands)

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

    2013-01-01

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

  4. America's Poisoned Playgrounds: Children and Toxic Chemicals.

    Science.gov (United States)

    Freedberg, Louis

    Next to chemical and farm workers, today's children are at the greatest risk from toxic chemicals. Through their normal play activities, children are exposed to a frightening array of toxic hazards, including lead, pesticides, arsenic, and unknown dangers from abandoned landfills and warehouses. Through a series of documented examples, the author…

  5. Better Tomorrow of China Rubber Chemicals Industry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    I. Development of China Rubber Chemicals Industry During the "11th Five-Year Plan" period, China rubber Chemicals industry fully implemented the development guideline of "Adhering to science and technology development, developing green chemistry with environmental protection, safety and energy conservation as the core, and building enterprise and world brands". With the great support of the state,

  6. Chemical Safety Vulnerability Working Group Report

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

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

  7. Beyond petrochemicals: The renewable chemicals industry

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  8. Standardized chemical synthesis of Pseudomonas aeruginosa pyocyanin

    Directory of Open Access Journals (Sweden)

    Rajkumar Cheluvappa

    2014-01-01

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

  9. 40 CFR 720.85 - Chemical identity.

    Science.gov (United States)

    2010-07-01

    ... particular chemical substance, and agree to furnish to EPA upon request: (A) An elemental analysis. (B...? How could a competitor use such information given the fact that the identity of the substance...) Has the identity of the chemical substance been kept confidential to the extent that your...

  10. Nanoscale porosity in pigments for chemical sensing

    OpenAIRE

    Kemling, Jonathan W.; Suslick, Kenneth S.

    2011-01-01

    Porous pigments in which chemically responsive dyes have been immobilized in a matrix of organically modified siloxanes (ormosils) have been prepared and characterized by AFM, TEM, EDS, and optical analysis. In typical chemical sensing applications, an array of 36 different porous ormosil pigments are deposited on polyethylene terephthalate (PET) film.

  11. Nanoscale porosity in pigments for chemical sensing.

    Science.gov (United States)

    Kemling, Jonathan W; Suslick, Kenneth S

    2011-05-01

    Porous pigments in which chemically responsive dyes have been immobilized in a matrix of organically modified siloxanes (ormosils) have been prepared and characterized by AFM, TEM, EDS, and optical analysis. In typical chemical sensing applications, an array of 36 different porous ormosil pigments are deposited on polyethylene terephthalate (PET) film.

  12. Multiple chemical sensitivity, en veldefineret lidelse?

    DEFF Research Database (Denmark)

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

    2006-01-01

    , even though a number of theories have been proposed. The authors of this review conclude that this is a functional condition. These patients need information and treatment in accordance with this fact. Instead of being advised how to avoid exposure to chemicals, they should be properly trained...... in appropriate confrontation with the chemicals encountered in everyday life....

  13. Multiple chemical sensitivity, en veldefineret lidelse?

    DEFF Research Database (Denmark)

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

    2006-01-01

    mechanisms, even though a number of theories have been proposed. The authors of this review conclude that this is a functional condition. These patients need information and treatment in accordance with this fact. Instead of being advised how to avoid exposure to chemicals, they should be properly trained...... in appropriate confrontation with the chemicals encountered in everyday life....

  14. Cytologic Effects of Air Force Chemicals

    Science.gov (United States)

    1980-11-01

    amounts of methylated guanine residues in the DNA. The DNA samples were hydrolyzed and chromatographed using high pressure liquid chromatography ( HPLC ...induced in freshly isolated lymphocytes by four chemicals, 4NQO, MMS, HN2 and mitomycin C (MMC). The differences in DRS are probably due to the chemical

  15. Graphene composites containing chemically bonded metal oxides

    Indian Academy of Sciences (India)

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

    2013-08-01

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

  16. Eye irritation: updated reference chemicals data bank.

    Science.gov (United States)

    Bagley, D M; Gardner, J R; Holland, G; Lewis, R W; Vrijhof, H; Walker, A P

    1999-06-01

    A list of 55 chemicals for which comprehensive rabbit eye irritation data were available was published by ECETOC in 1992. Similar data for a further 77 chemicals are now available. The total of chemicals included in the enlarged data bank is 132, assessed in 149 in vivo studies in rabbits. 28 of the chemicals were tested as solids, 24 as aqueous solutions. No new in vivo testing was carried out in order to qualify a chemical for inclusion in the data bank. The chemicals are available at known, high, consistent purity and are expected to be stable in storage. The in vivo data have been generated since 1981 in studies carried out according to OECD Test Guideline 405 and following the principles of Good Laboratory Practice. The data were obtained from tests normally using at least three animals evaluated at the same time, involving instillation of 0.1ml (or equivalent weight) into the conjunctival sac, and in which observations were made at least 1, 2 and 3 days after instillation. The chemicals are ranked for eye irritation potential on the basis of a 'modified maximum average score'. The reference chemicals data bank should be of use in validation tests of promising alternatives to the in vivo rabbit eye irritation test.

  17. The precautionary principle and chemicals regulation

    DEFF Research Database (Denmark)

    Løkke, Søren

    2006-01-01

    . Conclusions: It is concluded that the role of the precautionary principle in chemicals regulation will require continued scrutiny in the future shaping of the REACH strategy. Perspectives: Continued development of robust and precaution-based chemicals regulation will have to involve both new data......-generation strategies and new forms of political decision-making, with special attention given to transparency and deliberative policymaking....

  18. Thyroid effects of endocrine disrupting chemicals

    DEFF Research Database (Denmark)

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

    2012-01-01

    In recent years, many studies of thyroid-disrupting effects of environmental chemicals have been published. Of special concern is the exposure of pregnant women and infants, as thyroid disruption of the developing organism may have deleterious effects on neurological outcome. Chemicals may exert ...

  19. A Course in Chemical Reactor Design.

    Science.gov (United States)

    Takoudis, Christos G.

    1983-01-01

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

  20. Operating Modes Of Chemical Reactors Of Polymerization

    Directory of Open Access Journals (Sweden)

    Meruyert Berdieva

    2012-05-01

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

  1. Enhancing Thai Students' Learning of Chemical Kinetics

    Science.gov (United States)

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

    2009-01-01

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

  2. Physical and Chemical Processing in Flames

    Science.gov (United States)

    2013-08-12

    than the classical Troe formula, and the development of a Chemical Explosive Mode Analysis ( CEMA ) computation algorithm that allows on-the-fly...6-311++G(d,p) method. 3. Flame Stabilization and Chemical Explosive Mode Analysis ( CEMA ) Flame stabilization is essential in the understanding of

  3. Commodity chemicals from forest biomass - Bioforest

    Energy Technology Data Exchange (ETDEWEB)

    Granstrom, T. [Aalto University, Espoo (Finland)], email: tom.granstrom@aalto.fi

    2012-07-01

    To develop an economic process for production of commodity chemicals from mixed forest biomass (tree tops, limbs, twigs and stumps from softwoods and hardwoods) and recycled fibers within an integrated forest products complex. The chemicals that will be produced are: butanol, isopropanol and ethanol.

  4. 3F: A Leading Fluorine Chemical Company

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  5. Finding Chemical Anchors in the Kitchen

    Science.gov (United States)

    Haim, Liliana

    2005-01-01

    ''The Chemistry Kitchen'', a unit composed of five activities with kitchen elements for elementary students ages 9-11, introduces the children to the skills and chemical working ideas to be used later as anchors for chemical concepts. These activities include kitchen elements, determining the relative mass and so on.

  6. Use and Misuse of Chemical Reactivity Spreadsheets

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, F

    2005-09-20

    Misidentifying chemical hazards can have serious deleterious effects. Consequences of not identifying a chemical are obvious and include fires, explosions, injury to workers, etc. Consequences of identifying hazards that are really not present can be equally as bad. Misidentifying hazards can result in increased work with loss of productivity, increased expenses, utilization/consumption of scarce resources, and the potential to modify the work to include chemicals or processes that are actually more hazardous than those originally proposed. For these reasons, accurate hazard identification is critical to any safety program. Hazard identification in the world of chemistry is, at best, a daunting task. The knowing or understanding, of the reactions between any of approximately twelve million known chemicals that may be hazardous, is the reason for this task being so arduous. Other variables, such as adding other reactants/contaminants or changing conditions (e.g., temperature, pressure, or concentration), make hazard determination something many would construe as being more than impossibly difficult. Despite these complexities, people who do not have an extensive background in the chemical sciences can be called upon to perform chemical hazard identification. Because hazard identification in the area of chemical safety is so burdensome and because people with a wide variety of training are called upon to perform this work, tools are required to aid in chemical hazard identification. Many tools have been developed. Unfortunately, many of these tools are not seen as the limited resource that they are and are used inappropriately.

  7. Analysis, synthesis and design of chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Turton, R. [West Virginia Univ., Morgantown, WV (United States); Bailie, R.C.; Whiting, W.B.

    1998-12-31

    The book illustrates key concepts through a running example from the real world: the manufacture of benzene; covers design, economic considerations, troubleshooting and health/environmental safety; and includes exclusive software for estimating chemical manufacturing equipment capital costs. This book will help chemical engineers optimize the efficiency of production processes, by providing both a philosophical framework and detailed information about chemical process design. Design is the focal point of the chemical engineering practice. This book helps engineers and senior-level students hone their design skills through process design rather than simply plant design. It introduces all the basics of process simulation. Learn how to size equipment, optimize flowsheets, evaluate the economics of projects, and plan the operation of processes. Learn how to use Process Flow Diagrams; choose the operating conditions for a process; and evaluate the performance of existing processes and equipment. Finally, understand how chemical process design impacts health, safety, the environment and the community.

  8. Chemical Sciences Division: Annual report 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

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

  9. Surface wave chemical detector using optical radiation

    Science.gov (United States)

    Thundat, Thomas G.; Warmack, Robert J.

    2007-07-17

    A surface wave chemical detector comprising at least one surface wave substrate, each of said substrates having a surface wave and at least one measurable surface wave parameter; means for exposing said surface wave substrate to an unknown sample of at least one chemical to be analyzed, said substrate adsorbing said at least one chemical to be sensed if present in said sample; a source of radiation for radiating said surface wave substrate with different wavelengths of said radiation, said surface wave parameter being changed by said adsorbing; and means for recording signals representative of said surface wave parameter of each of said surface wave substrates responsive to said radiation of said different wavelengths, measurable changes of said parameter due to adsorbing said chemical defining a unique signature of a detected chemical.

  10. Continuum thermodynamics of chemically reacting fluid mixtures

    CERN Document Server

    Bothe, Dieter

    2014-01-01

    We consider viscous and heat conducting mixtures of molecularly miscible chemical species forming a fluid in which the constituents can undergo chemical reactions. Assuming a common temperature for all components, a first main aim is the derivation of a closed system of partial mass and partial momentum balances plus a common balance of internal energy. This is achieved by careful exploitation of the entropy principle which, in particular, requires appropriate definitions of absolute temperature and chemical potentials based on an adequate definition of thermal energy that excludes diffusive contributions. The latter is crucial in order to obtain a closure framework for the interaction forces between the different species. The interaction forces split into a thermo-mechanical and a chemical part, where the former turns out to be symmetric if binary interactions are assumed. In the non-reactive case, this leads to a system of Navier-Stokes type sub-systems, coupled by interspecies friction forces. For chemical...

  11. Chemical reactor modeling multiphase reactive flows

    CERN Document Server

    Jakobsen, Hugo A

    2014-01-01

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

  12. Chemical risk: strategies for social intervention

    Directory of Open Access Journals (Sweden)

    A. A. Calera Rubio

    2002-06-01

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

  13. Modeling Microscopic Chemical Sensors in Capillaries

    CERN Document Server

    Hogg, Tad

    2008-01-01

    Nanotechnology-based microscopic robots could provide accurate in vivo measurement of chemicals in the bloodstream for detailed biological research and as an aid to medical treatment. Quantitative performance estimates of such devices require models of how chemicals in the blood diffuse to the devices. This paper models microscopic robots and red blood cells (erythrocytes) in capillaries using realistic distorted cell shapes. The models evaluate two sensing scenarios: robots moving with the cells past a chemical source on the vessel wall, and robots attached to the wall for longer-term chemical monitoring. Using axial symmetric geometry with realistic flow speeds and diffusion coefficients, we compare detection performance with a simpler model that does not include the cells. The average chemical absorption is quantitatively similar in both models, indicating the simpler model is an adequate design guide to sensor performance in capillaries. However, determining the variation in forces and absorption as cells...

  14. Chemical composition of Earth-like planets

    CERN Document Server

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

    2015-01-01

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

  15. 78 FR 55326 - Determinations Regarding Use of Chemical Weapons in Syria Under the Chemical and Biological...

    Science.gov (United States)

    2013-09-10

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

  16. Identification of chemicals related to the chemical weapons convention during an interlaboratory proficiency test

    NARCIS (Netherlands)

    Hooijschuur, E.W.J.; Hulst, A.G.; Jong, A.L. de; Reuver, L.P. de; Krimpen, S.H. van; Baar, B.L.M. van; Wils, E.R.J.; Kientz, C.E.; Brinkman, U.A.Th

    2002-01-01

    In order to test the ability of laboratories to detect and identify chemicals related to the Chemical Weapons Convention (CWC), which prohibits the development, production, stockpiling and use of chemical weapons, and to designate laboratories for this task, the Technical Secretariat of the Organisa

  17. Effect of thermal, chemical and thermo-chemical pre-treatments to enhance methane production

    DEFF Research Database (Denmark)

    Rafique, Rashad; Poulsen, Tjalfe; Nizami, Abdul-Sattar

    2010-01-01

    -treatments: thermal, thermo-chemical and chemical pre-treatments on the biogas and methane potential of dewatered pig manure. A laboratory scale batch digester is used for these pre-treatments at different temperature range (25 degrees C-150 degrees C). Results showed that thermo-chemical pretreatment has high effect...

  18. Learning to predict chemical reactions.

    Science.gov (United States)

    Kayala, Matthew A; Azencott, Chloé-Agathe; Chen, Jonathan H; Baldi, Pierre

    2011-09-26

    Being able to predict the course of arbitrary chemical reactions is essential to the theory and applications of organic chemistry. Approaches to the reaction prediction problems can be organized around three poles corresponding to: (1) physical laws; (2) rule-based expert systems; and (3) inductive machine learning. Previous approaches at these poles, respectively, are not high throughput, are not generalizable or scalable, and lack sufficient data and structure to be implemented. We propose a new approach to reaction prediction utilizing elements from each pole. Using a physically inspired conceptualization, we describe single mechanistic reactions as interactions between coarse approximations of molecular orbitals (MOs) and use topological and physicochemical attributes as descriptors. Using an existing rule-based system (Reaction Explorer), we derive a restricted chemistry data set consisting of 1630 full multistep reactions with 2358 distinct starting materials and intermediates, associated with 2989 productive mechanistic steps and 6.14 million unproductive mechanistic steps. And from machine learning, we pose identifying productive mechanistic steps as a statistical ranking, information retrieval problem: given a set of reactants and a description of conditions, learn a ranking model over potential filled-to-unfilled MO interactions such that the top-ranked mechanistic steps yield the major products. The machine learning implementation follows a two-stage approach, in which we first train atom level reactivity filters to prune 94.00% of nonproductive reactions with a 0.01% error rate. Then, we train an ensemble of ranking models on pairs of interacting MOs to learn a relative productivity function over mechanistic steps in a given system. Without the use of explicit transformation patterns, the ensemble perfectly ranks the productive mechanism at the top 89.05% of the time, rising to 99.86% of the time when the top four are considered. Furthermore, the system

  19. Quantitative prediction of radio frequency induced local heating derived from measured magnetic field maps in magnetic resonance imaging: A phantom validation at 7 T

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaotong; Liu, Jiaen [Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Van de Moortele, Pierre-Francois; Schmitter, Sebastian [Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota 55455 (United States); He, Bin, E-mail: binhe@umn.edu [Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Institute for Engineering in Medicine, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2014-12-15

    Electrical Properties Tomography (EPT) technique utilizes measurable radio frequency (RF) coil induced magnetic fields (B1 fields) in a Magnetic Resonance Imaging (MRI) system to quantitatively reconstruct the local electrical properties (EP) of biological tissues. Information derived from the same data set, e.g., complex numbers of B1 distribution towards electric field calculation, can be used to estimate, on a subject-specific basis, local Specific Absorption Rate (SAR). SAR plays a significant role in RF pulse design for high-field MRI applications, where maximum local tissue heating remains one of the most constraining limits. The purpose of the present work is to investigate the feasibility of such B1-based local SAR estimation, expanding on previously proposed EPT approaches. To this end, B1 calibration was obtained in a gelatin phantom at 7 T with a multi-channel transmit coil, under a particular multi-channel B1-shim setting (B1-shim I). Using this unique set of B1 calibration, local SAR distribution was subsequently predicted for B1-shim I, as well as for another B1-shim setting (B1-shim II), considering a specific set of parameter for a heating MRI protocol consisting of RF pulses plaid at 1% duty cycle. Local SAR results, which could not be directly measured with MRI, were subsequently converted into temperature change which in turn were validated against temperature changes measured by MRI Thermometry based on the proton chemical shift.

  20. Chemical Sniffing Instrumentation for Security Applications.

    Science.gov (United States)

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

    2016-07-27

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

  1. ECVAM, ECETOC and the EU chemicals policy.

    Science.gov (United States)

    Botham, Philip A

    2002-12-01

    ECVAM's initiatives in validation have received significant support from the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC), especially through the provision of reference chemical data banks, which contain peer-reviewed, high-quality in vivo data on commercially available chemical substances. Chemicals have been selected from these ECETOC data banks for validation studies on alternative methods for skin corrosion and irritation and for eye irritation and, in addition, an ECETOC task force peer-reviewed the selection and classification, on the basis of in vivo data, of chemicals used in the validation of three alternative methods for developmental toxicity. More recently, ECVAM and ECETOC have been pursuing parallel initiatives on the proposed new EU chemicals policy, with the common goals of ensuring that industry and European Commission resources are used to investigate only those chemicals that pose a significant risk to human health and the environment, and that the Policy requires that any testing which is required follows the Three Rs principles of reduction, refinement and replacement.

  2. A thermodynamical framework for chemically reacting systems

    Science.gov (United States)

    Kannan, K.; Rajagopal, K. R.

    2011-04-01

    In this paper, we develop a thermodynamic framework that is capable of describing the response of viscoelastic materials that are undergoing chemical reactions that takes into account stoichiometry. Of course, as a special sub-case, we can also describe the response of elastic materials that undergo chemical reactions. The study generalizes the framework developed by Rajagopal and co-workers to study the response of a disparate class of bodies undergoing entropy producing processes. One of the quintessential feature of this framework is that the second law of thermodynamics is formulated by introducing Gibbs' potential, which is the natural way to study problems involving chemical reactions. The Gibbs potential-based formulation also naturally leads to implicit constitutive equations for the stress tensor. Another feature of the framework is that the constraints due to stoichiometry can also be taken into account in a consistent manner. The assumption of maximization of the rate of entropy production due to dissipation, heat conduction, and chemical reactions is invoked to determine an equation for the evolution of the natural configuration κ p( t)( B), the heat flux vector and a novel set of equations for the evolution of the concentration of the chemical constituents. To determine the efficacy of the framework with regard to chemical reactions, those occurring during vulcanization, a challenging set of chemical reactions, are chosen. More than one type of reaction mechanism is considered and the theoretically predicted distribution of mono, di and polysulfidic cross-links agree reasonably well with available experimental data.

  3. Chemical Engineering Education - Current and Future Trends

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    The chemical industry today is changed from the chemical industry of twenty-five years ago. Clear evidence of this change comes from the jobs taken by graduating chemical professionals in North America, Europe, and some of the Asian countries. Twenty-five years ago, eighty percent of these gradua......The chemical industry today is changed from the chemical industry of twenty-five years ago. Clear evidence of this change comes from the jobs taken by graduating chemical professionals in North America, Europe, and some of the Asian countries. Twenty-five years ago, eighty percent...... should be measured on their level of knowledge and the understanding they develop, rather than the amount of time they spend with the tutors. According to the Bologna Process, the first and the second cycle degrees should have different orientations and various profiles in order to accommodate...... completion of the first cycle, students can continue their study with a second cycle program of chemical engineering with 90-120 credits for a further 18-24 months. For the first and second cycles, the EFCE recommend a set of programme outcomes (knowledge and understanding, engineering analysis, engineering...

  4. Platform Chemicals from an Oilseed Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    Tupy, Mike; Schrodi Yann

    2006-11-06

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

  5. Chemical Engineering in the "BIO" world.

    Science.gov (United States)

    Chiarappa, Gianluca; Grassi, Mario; Abrami, Michela; Abbiati, Roberto Andrea; Barba, Anna Angela; Boisen, Anja; Brucato, Valerio; Ghersi, Giulio; Caccavo, Diego; Cascone, Sara; Caserta, Sergio; Elvassore, Nicola; Giomo, Monica; Guido, Stefano; Lamberti, Gaetano; Larobina, Domenico; Manca, Davide; Marizza, Paolo; Tomaiuolo, Giovanna; Grassi, Gabriele

    2016-06-02

    Modern Chemical Engineering was born around the end of the 19th century in Great Britain, Germany, and the USA, the most industrialized countries at that time. Milton C. Whitaker, in 1914, affirmed that the difference between Chemistry and Chemical Engineering lies in the capability of chemical engineers to transfer laboratory findings to the industrial level. Since then, Chemical Engineering underwent huge transformations determining the detachment from the original Chemistry nest. The beginning of the sixties of the 20th century saw the development of a new branch of Chemical Engineering baptized Biomedical Engineering by Peppas and Langer and that now we can name Biological Engineering. Interestingly, although Biological Engineering focused on completely different topics from Chemical Engineering ones, it resorted to the same theoretical tools such as, for instance, mass, energy and momentum balances. Thus, the birth of Biological Engineering may be considered as a Darwinian evolution of Chemical Engineering similar to that experienced by mammals which, returning to water, used legs and arms to swim. From 1960 on, Biological Engineering underwent a considerable evolution as witnessed by the great variety of topics covered such as hemodialysis, release of synthetic drugs, artificial organs and, more recently, delivery of small interfering RNAs (siRNA). This review, based on the activities developed in the frame of our PRIN 2010-11 (20109PLMH2) project, tries to recount origins and evolution of Chemical Engineering illustrating several examples of recent and successful applications in the biological field. This, in turn, may stimulate the discussion about the Chemical Engineering students curriculum studiorum update.

  6. Implementing the chemical weapons convention

    Energy Technology Data Exchange (ETDEWEB)

    Kellman, B.; Tanzman, E. A.

    1999-12-07

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

  7. Fungitoxicity of chemical analogs with heartwood toxins.

    Science.gov (United States)

    Grohs, B M; Kunz, B

    1998-07-01

    Trans-stilbene and tropolone as chemical analogs with naturally occurring fungitoxic heartwood compounds were studied with respect to their fungitoxic potency. While stilbene showed no fungitoxic activity towards the fungi Aureobasidium pullulans var. melanogenum, Penicillium glabrum, and Trichoderma harzianum in the concentrations tested, the minimal inhibiting concentration of tropolone was 10(-3) M for Penicillium glabrum and Trichoderma harzianum, and 10(-5) M for Aureobasidium pullulans var. melanogenum. In all cases, the effect of tropolone was a fungistatic one. Using chemical analogs for assessing the chemical basis of the fungitoxicity of tropolone, this substance proved to be the only compound tested which possesses fungitoxic properties.

  8. Nanotube-Based Chemical and Biomolecular Sensors

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  9. Protein engineering approaches to chemical biotechnology.

    Science.gov (United States)

    Chen, Zhen; Zeng, An-Ping

    2016-12-01

    Protein engineering for the improvement of properties of biocatalysts and for the generation of novel metabolic pathways plays more and more important roles in chemical biotechnology aiming at the production of chemicals from biomass. Although widely used in single-enzyme catalysis process, protein engineering is only being increasingly explored in recent years to achieve more complex in vitro and in vivo biocatalytic processes. This review focuses on major contributions of protein engineering to chemical biotechnology in the field of multi-enzymatic cascade catalysis and metabolic engineering. Especially, we discuss and highlight recent strategies for combining pathway design and protein engineering for the production of novel products.

  10. Chemical reactions in low-g

    Science.gov (United States)

    Grodzka, P. G.; Facemire, B. R.

    1978-01-01

    The Apollo-Soyuz flight experiment, 'Chemical Foams' demonstrated that foams and air/liquid dispersions are much more stable in low-gravity than on the ground. It thus should be possible to conduct unique chemical reactions in space foams. The low-g results and subsequent ground work on the formaldehyde clock reaction indicate that the reaction is strongly influenced by (1) dissociated and undissociated solution species being adsorbed at solid/liquid and gas/liquid surfaces and (2) chemical reaction rates apparently being affected by long-range forces determined by the liquid mass and the extent and nature of all surface interfaces.

  11. Chemical analysis of aquatic pheromones in fish.

    Science.gov (United States)

    Stewart, Michael; Baker, Cindy F; Sorensen, Peter W

    2013-01-01

    Pheromones are chemicals that pass between members of the same species that have inherent meaning. In the case of fish, pheromones are water-soluble and found in low concentrations. As such, sensitive and selective methods are needed to separate and analyze these pheromones from an environmental matrix that may contain many other chemicals. This chapter describes a generic method used to concentrate and identify these chemicals and two extremely sensitive and selective methods for analysis, namely, mass spectrometry and enzyme-linked immunosorbent assay.

  12. Flows and chemical reactions in heterogeneous mixtures

    CERN Document Server

    Prud'homme, Roger

    2014-01-01

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

  13. Chemical Sciences Division annual report 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    The division is one of ten LBL research divisions. It is composed of individual research groups organized into 5 scientific areas: chemical physics, inorganic/organometallic chemistry, actinide chemistry, atomic physics, and chemical engineering. Studies include structure and reactivity of critical reaction intermediates, transients and dynamics of elementary chemical reactions, and heterogeneous and homogeneous catalysis. Work for others included studies of superconducting properties of high-{Tc} oxides. In FY 1994, the division neared completion of two end-stations and a beamline for the Advanced Light Source, which will be used for combustion and other studies. This document presents summaries of the studies.

  14. Chemicals Industry New Process Chemistry Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2000-08-01

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

  15. Rhizosphere chemical dialogues: plant-microbe interactions

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-12-01

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

  16. Chemical Dynamics at the Advanced Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Baer, T.; Berrah, N.; Fadley, C.; Moore, C.B.; Neumark, D.M.; Ng, C.Y.; Ruscic, B.; Smith, N.V.; Suits, A.G.; Wodtke, A.M.

    1999-02-02

    A day-long retreat was held January 15, 1999 to chart the future directions for chemical dynamics studies at the Advanced Light Source. This represents an important period for the Chemical Dynamics Beamline, as the hardware is well-developed, most of the initial experimental objectives have been realized and the mission is now to identify the future scientific priorities for the beamline and attract users of the highest caliber. To this end, we have developed a detailed scientific program for the near term; identified and prioritized the long range scientific opportunities, identified essential new hardware, and outlined an aggressive outreach program to involve the chemical physics community.

  17. Chemical Reactions in Turbulent Mixing Flows

    Science.gov (United States)

    1989-10-15

    example, Levenspiel (1962). Eq. 27 would be necessary. A first guess is that it might scale with 6/z as it does for subsonic flow. i.e. -(r, s; M., -0 ) -(r...France), 45-63. KELLER. J. 0. and DAILY. J. W. (1985] "The Effect of Highly Exothermic Chemical Reaction on a Two-Dimensional Mixing Layer", LEVENSPIEL ...0. [19621 Chemical Reaction Engineering. An Introduc- ALAA J. 23(12), 1937-1945. tion to the Design of Chemical Reactors . (John Wiley). KERSTEIN. A

  18. Production of chemicals and fuels from biomass

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-15

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

  19. Chemical leasing business models: a contribution to the effective risk management of chemical substances.

    Science.gov (United States)

    Ohl, Cornelia; Moser, Frank

    2007-08-01

    Chemicals indisputably contribute greatly to the well-being of modern societies. Apart from such benefits, however, chemicals often pose serious threats to human health and the environment when improperly handled. Therefore, the European Commission has proposed a regulatory framework for the Registration, Evaluation and Authorization of Chemicals (REACH) that requires companies using chemicals to gather pertinent information on the properties of these substances. In this article, we argue that the crucial aspect of this information management may be the honesty and accuracy of the transfer of relevant knowledge from the producer of a chemical to its user. This may be particularly true if the application of potentially hazardous chemicals is not part of the user's core competency. Against this background, we maintain that the traditional sales concept provides no incentives for transferring this knowledge. The reason is that increased user knowledge of a chemical's properties may raise the efficiency of its application. That is, excessive and unnecessary usage will be eliminated. This, in turn, would lower the amount of chemicals sold and in competitive markets directly decrease profits of the producer. Through the introduction of chemical leasing business models, we attempt to present a strategy to overcome the incentive structure of classical sales models, which is counterproductive for the transfer of knowledge. By introducing two models (a Model A that differs least and a Model B that differs most from traditional sales concepts), we demonstrate that chemical leasing business models are capable of accomplishing the goal of Registration, Evaluation and Authorization of Chemicals: to effectively manage the risk of chemicals by reducing the total quantity of chemicals used, either by a transfer of applicable knowledge from the lessor to the lessee (Model A) or by efficient application of the chemical by the lessor him/herself (Model B).

  20. Inflation Rates, Car Devaluation, and Chemical Kinetics

    Science.gov (United States)

    Pogliani, Lionello; Berberan-Santos, Màrio N.

    1996-10-01

    The inflation rate problem of a modern economy shows quite interesting similarities with chemical kinetics and especially with first-order chemical reactions. In fact, capital devaluation during periods of rather low inflation rates or inflation measured over short periods shows a dynamics formally similar to that followed by first-order chemical reactions and they can thus be treated by the aid of the same mathematical formalism. Deviations from this similarity occurs for higher inflation rates. The dynamics of price devaluation for two different types of car, a compact car and a luxury car, has been followed for seven years long and it has been established that car devaluation is a process that is formally similar to a zeroth-order chemical kinetic process disregarding the type of car, if car devaluation is much faster than money devaluation. In fact, expensive cars devaluate with a faster rate than inexpensive cars.

  1. Chemical structure and dynamics. Annual report 1995

    Energy Technology Data Exchange (ETDEWEB)

    Colson, S.D.; McDowell, R.S.

    1996-05-01

    The Chemical Structure and Dynamics program is a major component of Pacific Northwest National Laboratory`s Environmental Molecular Sciences Laboratory (EMSL), providing a state-of-the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for the characterization of waste tanks and pollutant distributions, and for detection and monitoring of trace atmospheric species.

  2. 16 CFR 1507.2 - Prohibited chemicals.

    Science.gov (United States)

    2010-01-01

    ... chemicals: (a) Arsenic sulfide, arsenates, or arsenites. (b) Boron. (c) Chlorates, except: (1) In colored... barium chlorate. (d) Gallates or gallic acid. (e) Magnesium (magnesium/aluminum alloys, called...

  3. Large JV Chemical Plant Kicks Off

    Institute of Scientific and Technical Information of China (English)

    Liu Jie

    2002-01-01

    @@ Construction of one of the largest petrochemical joint venture projects in the country - and BP's largest project in China - kicked off in the Shanghai Chemical Industrial Park in late-March, 2002.

  4. Collaborating for Multi-Scale Chemical Science

    Energy Technology Data Exchange (ETDEWEB)

    William H. Green

    2006-07-14

    Advanced model reduction methods were developed and integrated into the CMCS multiscale chemical science simulation software. The new technologies were used to simulate HCCI engines and burner flames with exceptional fidelity.

  5. Possible interrelations among chemical freezeout conditions

    CERN Document Server

    Tawfik, A; Habashy, D M; Mohamed, M T; Abbas, E

    2016-01-01

    At thermal equilibrium, different chemical freezeout conditions have been proposed so far. They have an ultimate aim of proposing a universal description for the chemical freezeout parameters ($T_{ch}$ and $\\mu_b$), which are to be extracted from the statistical fitting of different particle ratios measured at various collision energies with calculations from thermal models. A systematic comparison between these conditions is presented. The physical meaning of each of them and their sensitivity to the hadron mass cuts are discussed. Based on availability, some of them are compared with recent lattice calculations. We found that most of these conditions are thermodynamically equivalent, especially at small baryon chemical potential. We propose that further crucial consistency tests should be performed at low energies. The fireball thermodynamics is another way of guessing conditions describing the chemical freezeout parameters extracted from high-energy experiments. We endorse the possibility that the various ...

  6. Chemical Processing Division monthly report, September 1966

    Energy Technology Data Exchange (ETDEWEB)

    Warren, J.H.

    1966-10-21

    This report, from the Chemical Processing Department at HAPO for September 1966, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; and employee-relations, and waste management.

  7. Chemical Processing Department monthly report, February 1965

    Energy Technology Data Exchange (ETDEWEB)

    Warren, J.H.

    1965-03-22

    This report, from the Chemical Processing Department at HAPO, discusses the following: production operation; purex and redox operation; finished products operation; maintenance; financial operations; facilities engineering; research; and employee relations.

  8. Chemical Processing Department monthly report, October 1963

    Energy Technology Data Exchange (ETDEWEB)

    Young, J. F.; Johnson, W. E.; Reinker, P. H.; Warren, J. H.; McCullugh, R. W.; Harmon, M. K.; Gartin, W. J.; LaFollette, T. G.; Shaw, H. P.; Frank, W. S.; Grim, K. G.; Warren, J. H.

    1963-11-21

    This report, for October 1963 from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; employee relations; weapons manufacturing operation; and safety and security.

  9. Spectroscopic Chemical Analysis Methods and Apparatus

    Science.gov (United States)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor); Lane, Arthur L. (Inventor)

    2017-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

  10. Storing the Wisdom: Chemical Concepts and Chemoinformatics

    Directory of Open Access Journals (Sweden)

    David Bawden

    2015-11-01

    Full Text Available The purpose of the paper is to examine the nature of chemical concepts, and the ways in which they are applied in chemoinformatics systems. An account of concepts in philosophy and in the information sciences leads to an analysis of chemical concepts, and their representation. The way in which concepts are applied in systems for information retrieval and for structure–property correlation are reviewed, and some issues noted. Attention is focused on the basic concepts or substance, reaction and property, on the organising concepts of chemical structure, structural similarity, periodicity, and on more specific concepts, including two- and three-dimensional structural patterns, reaction types, and property concepts. It is concluded that chemical concepts, despite (or perhaps because of their vague and mutable nature, have considerable and continuing value in chemoinformatics, and that an increased formal treatment of concepts may have value in the future.

  11. Agricultural Chemical Sourcebook for Wildlife Contaminants Specialists

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this handbook is to provide information to contaminant specialists involved in evaluating agricultural chemical impacts on wetlands. The handbook...

  12. Optical MEMS for chemical analysis and biomedicine

    CERN Document Server

    Jiang, Hongrui

    2016-01-01

    This book describes the current state of optical MEMS in chemical and biomedical analysis and brings together current trends and highlights topics representing the most exciting progress in recent years in the field.

  13. Thyroid disrupting chemicals: Mechanisms and mixtures

    Science.gov (United States)

    Environmental contaminants are known to act as thyroid disrupting chemicals (TDCs). Broadly defined, TDCs are xenobiotics that alter the structure or function of the thyroid gland, alter regulatory enzymes associated with thyroid hormone (TH) homeostasis, or change circulating o...

  14. Darcys Law Expressed by Chemical Index

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Darcys formula expressed by chemical indexes (ion activity a and saturation index f) is derived with the aid of the kinetics of multi-mineral dissolution. The implication of the formula and the relationship between the formula and the original Darcy′s law expressed by hydraulic index (hydraulic gradient, I ) are discussed here. An analytic expression is established in this paper for the determination of the residence time of groundwater by chemical indexes, whose equivalence to isotopic age is studled. The formulas are derived from the calculation of permeability coefficient (K), conductivity coefficient (T) and actual velocity of groundwater (U). Finally, this paper introduces hydrogeological chemical kinetics constant (kj) and its determination method, differential and integral equations for chemical kinetics of groundwater in three-dimensional space.

  15. EPA CHEMICAL PRIORITIZATION COMMUNITY OF PRACTICE.

    Science.gov (United States)

    IN 2005 THE NATIONAL CENTER FOR COMPUTATIONAL TOXICOLOGY (NCCT) ORGANIZED EPA CHEMICAL PRIORITIATION COMMUNITY OF PRACTICE (CPCP) TO PROVIDE A FORUM FOR DISCUSSING THE UTILITY OF COMPUTATIONAL CHEMISTRY, HIGH-THROUGHPUT SCREENIG (HTS) AND VARIOUS TOXICOGENOMIC TECHNOLOGIES FOR CH...

  16. Chemical Processing Department monthly report, June 1958

    Energy Technology Data Exchange (ETDEWEB)

    1958-07-22

    This report for June 1958, from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; and employee relations.

  17. Computer Simulation Instruction: Carrying out Chemical Experiments

    Directory of Open Access Journals (Sweden)

    Ibtesam Al-Mashaqbeh

    2014-05-01

    Full Text Available The purpose of this study was to investigate the effect of computer simulation Instruction (CSI on students' achievements: Carrying out chemical experiments to acquire chemical concepts for eleventh grade students. The subject of the study consisted two sections of a one girl's high school in Jordan. One section was randomly assigned to experimental group in which computer simulation Instruction (CSI was used, and the other section was randomly assigned to control group in which students were instructed by using the traditional teaching instruction. The findings indicated that there is progress on the part of the experimental group which used the computer simulation Instruction (CSI and this was reflected positively in the students’ achievement in carrying out chemical experiments to acquire chemical concepts.

  18. Chemical Reactions at Surfaces. Final Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2003-02-21

    The Gordon Research Conference (GRC) on Chemical Reactions at Surfaces was held at Holiday Inn, Ventura, California, 2/16-21/03. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  19. Chemical sensor with oscillating cantilevered probe

    Science.gov (United States)

    Adams, Jesse D

    2013-02-05

    The invention provides a method of detecting a chemical species with an oscillating cantilevered probe. A cantilevered beam is driven into oscillation with a drive mechanism coupled to the cantilevered beam. A free end of the oscillating cantilevered beam is tapped against a mechanical stop coupled to a base end of the cantilevered beam. An amplitude of the oscillating cantilevered beam is measured with a sense mechanism coupled to the cantilevered beam. A treated portion of the cantilevered beam is exposed to the chemical species, wherein the cantilevered beam bends when exposed to the chemical species. A second amplitude of the oscillating cantilevered beam is measured, and the chemical species is determined based on the measured amplitudes.

  20. Generic strategies for chemical space exploration.

    Science.gov (United States)

    Andersen, Jakob L; Flamm, Christoph; Merkle, Daniel; Stadler, Peter F

    2014-01-01

    The chemical universe of molecules reachable from a set of start compounds by iterative application of a finite number of reactions is usually so vast, that sophisticated and efficient exploration strategies are required to cope with the combinatorial complexity. A stringent analysis of (bio)chemical reaction networks, as approximations of these complex chemical spaces, forms the foundation for the understanding of functional relations in Chemistry and Biology. Graphs and graph rewriting are natural models for molecules and reactions. Borrowing the idea of partial evaluation from functional programming, we introduce partial applications of rewrite rules. A framework for the specification of exploration strategies in graph-rewriting systems is presented. Using key examples of complex reaction networks from carbohydrate chemistry we demonstrate the feasibility of this high-level strategy framework. While being designed for chemical applications, the framework can also be used to emulate higher-level transformation models such as illustrated in a small puzzle game.