WorldWideScience

Sample records for nonpolar anhydrous medium

  1. Rheology of zirconia suspensions in a nonpolar organic medium

    International Nuclear Information System (INIS)

    Moloney, V.M.B.; Parris, D.; Edirisinghe, M.J.

    1995-01-01

    Three dispersants (stearic acid, oleic acid, and poly-(12-hydroxystearic acid)) are compared for their ability to produce low-viscosity suspensions of zirconia in kerosene. Rheological measurements and sediment packing density measurements show that poly(12-hydroxystearic acid) is a better dispersant than stearic acid or oleic acid; this is explained in terms of the longer tail of the poly-(12-hydroxystearic acid) surfactant molecule. The amount of dispersant can be optimized to reduce viscosity and yield point of the suspension, and to eliminate thixotropic hysteresis. The use of a dispersion medium of lower viscosity than the dispersant makes it easy to detect when complete monolayer coverage has been achieved. The loss of pseudoplasticity, brought about by a higher degree of deflocculation, can be recovered by increasing the volume fraction of solids of a suspension and this is beneficial in the plastic forming of ceramics. Rheological measurements showed that these suspensions reach a critical state above a critical shear stress (τ c ). This critical state is described by several parameters, i.e., the Bingham yield stress (τ B ), the plastic viscosity (η PL ), and the critical shear rate (γ c ), which are dependent on the volume fraction of solids

  2. 21 CFR 168.110 - Dextrose anhydrous.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Dextrose anhydrous. 168.110 Section 168.110 Food... Table Sirups § 168.110 Dextrose anhydrous. (a) Dextrose anhydrous is purified and crystallized D-glucose... solids content is not less than 98.0 percent m/m. (b) The name of the food is “Dextrose anhydrous” or...

  3. Nonpolar solvation dynamics for a nonpolar solute in room ...

    Indian Academy of Sciences (India)

    Sandipa Indra

    2018-01-30

    Jan 30, 2018 ... Keywords. Solvation dynamics; nonpolar solvation; ionic liquid; molecular dynamics; linear response theory. 1. ... J. Chem. Sci. (2018) 130:3 spectrum of the excited probe molecule for imida- .... Therefore, the solute and the RTIL ions interact only ... interval of 30 ps from a long equilibrium trajectory of dura-.

  4. Anhydrous ethanol: A renewable source of energy

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Santosh; Singh, Neetu; Prasad, Ram [Department of Chemical Engineering, H. B. Technological Institute, Kanpur 208002 (India)

    2010-09-15

    Anhydrous ethanol is one of the biofuels produced today and it is a subset of renewable energy. It is considered to be an excellent alternative clean-burning fuel to gasoline. Anhydrous ethanol is commercially produced by either catalytic hydration of ethylene or fermentation of biomass. Any biological material that has sugar, starch or cellulose can be used as biomass for producing anhydrous ethanol. Since ethanol-water solution forms a minimum-boiling azeotrope of composition of 89.4 mol% ethanol and 10.6 mol% water at 78.2 C and standard atmospheric pressure, the dilute ethanol-water solutions produced by fermentation process can be continuously rectified to give at best solutions containing 89.4 mol% ethanol at standard atmospheric pressure. Therefore, special process for removal of the remaining water is required for manufacture of anhydrous ethanol. Various processes for producing anhydrous ethanol have been used/suggested. These include: (i) chemical dehydration process, (ii) dehydration by vacuum distillation process, (iii) azeotropic distillation process, (iv) extractive distillation processes, (v) membrane processes, (vi) adsorption processes and (vii) diffusion distillation process. These processes of manufacturing anhydrous ethanol have been improved continuously due to the increasingly strict requirements for quantity and quality of this product. The literature available on these processes is reviewed. These processes are also compared on the basis of energy requirements. (author)

  5. Transport of anhydrous ammoniac - risk assessment

    International Nuclear Information System (INIS)

    Castellano, S.; Degrange, J.P.; Hubert, P.; Pages, P.; Lamblin, J.

    1989-12-01

    This risk analysis of anhydrous ammonia transport in France was done within a study initiated by the Department of dangerous goods of the Ministry of transport. The study deals with the road and rail transportation of bulk anhydrous ammonia. After analysis of transport system and traffic, the transport accident risks are estimated, as well as their distribution on the French territory. Finally after a synthesis of results, a number of safety measures to be undertaken were identified. This is a joint study of SMC-CEPN, with a specific role of SEMA-METRA-CONSEIL concerning the traffic frequency, and the center for risk evaluation concerning nuclear safety

  6. Colloidosomes formed by nonpolar/polar/nonpolar nanoball amphiphiles

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hung-Yu; Sheng, Yu-Jane, E-mail: yjsheng@ntu.edu.tw, E-mail: hktsao@cc.ncu.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Tu, Sheng-Hung [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan (China); Tsao, Heng-Kwong, E-mail: yjsheng@ntu.edu.tw, E-mail: hktsao@cc.ncu.edu.tw [Department of Chemical and Materials Engineering and Department of Physics, National Central University, Jhongli 320, Taiwan (China)

    2014-08-07

    Fullerene-based amphiphiles are able to form bilayer vesicles in aqueous solution. In this study, the self-assembly behavior of polymer-tethered nanoballs (NBs) with nonpolar/polar/nonpolar (n-p-n{sup ′}) motif in a selective solvent is investigated by dissipative particle dynamics. A model NB bears two hydrophobic polymeric arms (n{sup ′}-part) tethered on an extremely hydrophobic NB (n-part) with hydrophilic patch (p-part) patterned on its surface. Dependent on the hydrophobicity and length of tethered arms, three types of aggregates are exhibited, including NB vesicle, core-shell micelle, and segmented-worm. NB vesicles are developed for a wide range of hydrophobic arm lengths. The presence of tethered arms perturbs the bilayer structure formed by NBs. The structural properties including the order parameter, membrane thickness, and area density of the inner leaflet decrease with increasing the arm length. These results indicate that for NBs with longer arms, the extent of interdigitation in the membrane rises so that the overcrowded arms in the inner corona are relaxed. The transport and mechanical properties are evaluated as well. As the arm length grows, the permeability increases significantly because the steric bulk of tethered arms loosens the packing of NBs. By contrast, the membrane tension decreases owing to the reduction of NB/solvent contacts by the polymer corona. Although fusion can reduce membrane tension, NB vesicles show strong resistance to fusion. Moreover, the size-dependent behavior observed in small liposomes is not significant for NB vesicles due to isotropic geometry of NB. Our simulation results are consistent with the experimental findings.

  7. Anhydrous hydrogen fluoride electrolyte battery. [Patent application

    Science.gov (United States)

    Not Available

    1972-06-26

    It is an object of the invention to provide a primary cell or battery using ammonium fluoride--anhydrous hydrogen fluoride electrolyte having improved current and power production capabilities at low temperatures. It is operable at temperatures substantially above the boiling point of hydrogen fluoride. (GRA)

  8. 46 CFR 151.50-32 - Ammonia, anhydrous.

    Science.gov (United States)

    2010-10-01

    ... enclosed anhydrous ammonia tanks complies with the following chemical and physical properties: (1) Boiling... requirements of § 151.50-30 for compressed gases are also applicable to the shipment of anhydrous ammonia...

  9. THz characterization of hydrated and anhydrous materials

    Science.gov (United States)

    Sokolnikov, Andre

    2011-06-01

    The characterization of anhydrous and hydrated forms of materials is of great importance to science and industry. Water content poses difficulties for successful identification of the material structure by THz radiation. However, biological tissues and hydrated forms of nonorganic substances still may be investigated by THz radiation. This paper outlines the range of possibilities of the above characterization, as well as provides analysis of the physical mechanism that allows or prevents penetration of THz waves through the substance. THz-TDS is used to measure the parameters of the characterization of anhydrous and hydrated forms of organic and nonorganic samples. Mathematical methods (such as prediction models of time-series analysis) are used to help identifying the absorption coefficient and other parameters of interest. The discovered dependencies allow designing techniques for material identification/characterization (e.g. of drugs, explosives, etc. that may have water content). The results are provided.

  10. Preparation of pure anhydrous rare earth chlorides

    International Nuclear Information System (INIS)

    Bel'kova, N.L.; Slastenova, N.M.; Batyaev, I.M.; Solov'ev, M.A.

    1979-01-01

    A method has been suggested for obtaining extra-pure anhydrous REE chlorides by chloridizing corresponding oxalates by chlorine in a fluid bed, the chloridizing agents being diluted by an inert gas in a ratio of 2-to-1. The method is applicable to the manufacture of quality chlorides not only of light, but also of heavy REE. Neodymium chloride has an excited life of tau=30 μs, this evidencing the absence of the damping impurities

  11. Electrochemistry of acid-base reactions in anhydrous hydrogen fluoride

    International Nuclear Information System (INIS)

    Masson, J.P.; Devynck, J.; Tremillon, B.

    1975-01-01

    Electrochemical studies were made in following media: water-HF mixtures, anhydrous HF and KF solutions in HF, solutions of the SbF5 type in HF. The acidity level of these solutions was evaluated using the R(H) functions based on the strehlow hypotheses. From the pH measurement in anhydrous HF, it was possible to get acid-base titration curves and pH buffers. The behavior of quinones in anhydrous HF is presented [fr

  12. 46 CFR 98.25-5 - How anhydrous ammonia may be carried.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false How anhydrous ammonia may be carried. 98.25-5 Section 98... Anhydrous Ammonia in Bulk § 98.25-5 How anhydrous ammonia may be carried. (a) Anhydrous ammonia shall be..., except as otherwise provided in paragraph (b) of this section. (b) When anhydrous ammonia is to be...

  13. Amperometric titration of thorium and some lanthanoids in acetic-acid medium using two indicator electrodes

    International Nuclear Information System (INIS)

    Khadeev, V.A.; Gevorgyan, A.M.; Talipov, Sh.T.; Kostylev, V.S.

    1979-01-01

    The votammetric behaviour of nitriletrimethylphosphonic acid (NTMP) in the medium of anhydrous acetic acid with different backgrounds in the anode region of polarization of a platinum microdisk electrode, is studied. The optimal conditions are found for the amperometric titration with two indicator electrodes of thorium and same lanthanides by a NTMP solution in anhydrous acetic medium. The influence of foreign anions and cations on the results of titration by the NTPM solution in anhydrous acetic acid is studied. The selectivity of titration in anhydrous medium is higher than in aqueous

  14. Potentiometric titrations in anhydrous acetic acid

    International Nuclear Information System (INIS)

    Le Port, L.

    1966-03-01

    The method used for studying anhydrous acetic acid is potentiometry with a glass electrode. We have in this way studied the titration of common inorganic acids (HClO 4 - HBr - H 2 SO 4 - HCl - HNO 3 - H 3 PO 4 ) and of some metallic salts. Furthermore we have shown that complex acids are formed between HCl and some metallic chlorides. An analysis of the titration curves for the inorganic acids against pyridinium chloride has made it possible to calculate a certain number of values for the dissociation pK of these acids and of the corresponding pyridinium salts. The titration of metallic perchlorates constitutes a method of studying the stability of acetates; we have thus been able to draw up a classification for some of these acetates. The metallic chlorides studied fall into two groups according to their behaviour in weak or strong acids. The differences have been explained on the basis of the role played by solvolysis. In the third part we have studied the acidic properties of mixtures of HCl with certain metallic chlorides. This work has demonstrated the existence, in certain cases, of acid complexes of the type (HCl) m MCl n . (author) [fr

  15. Harvesting Water from Air: Using Anhydrous Salt with Sunlight

    KAUST Repository

    Li, Renyuan; Shi, Yusuf; Shi, Le; Alsaedi, Mossab.; Wang, Peng

    2018-01-01

    Atmospheric water is abundant alternative water resource, equivalent to 6 times of water in all rivers on Earth. This work screens 14 common anhydrous and hydrated salt couples in terms of their physical and chemical stability, water vapor

  16. The γ-irradiation stability of anhydrous ethylenediamine

    International Nuclear Information System (INIS)

    Zhong Zhijing; Long Suqun; Fu Yibei; Xu Yunshu

    2005-01-01

    Anhydrous Ethylenediamine (AEDA) was irradiated in air or nitrogen at ambient temperatures by 60 Co γ-rays. The radiation degradation products were analyzed by means of GC, GC/MS, MS and FT-IR, etc. Notable gaseous products such as hydrogen, methane, ethylene, ammonia, and some volatile liquid state radiolysis products as well, were examined, and many kinds of polymerized products were detected in the liquid remain sample. It was found that under certain conditions both the hydrogen and methane contents of the products increased with dose. Remarkable effects of radiation degradation and radiation polymerization were observed, and even severe effects were found in nitrogen ambience. Therefore, a worse γ-irradiation stability of anhydrous ethylenediamine was demonstrated. The radiation polymerization of anhydrous ethylenediamine was not reported before. (authors)

  17. Interaction of Ketotifen Fumarate with Anhydrous Theophylline in ...

    African Journals Online (AJOL)

    Purpose: The purpose of the present study was to investigate interaction between ketotifen fumarate and anhydrous theophylline in aqueous media of various pH. Methods: By using Job's continuous-variation analysis and Ardon's spectrophotomeric methods, the values of stability constants of theophylline with ketotifen ...

  18. Effect of anhydrous magnesium sulphate fertilizer and cutting ...

    African Journals Online (AJOL)

    Effect of anhydrous magnesium sulphate fertilizer on Panicum maximum yield and chemical composition of the resultant herbage harvested at 3, 4 and 5 weeks of age was investigated. The treatments were labeled T1 to T6. T1 was fertilized and harvested at 3 weeks cutting interval, T2 was fertilized and harvested at 4 ...

  19. Anhydrous Ammonia Training Module. Trainer's Package. Participant's Package.

    Science.gov (United States)

    Beaudin, Bart; And Others

    This document contains a trainer's and a participant's package for teaching employees on site safe handling procedures for working with anhydrous ammonia, especially on farms. The trainer's package includes the following: a description of the module; a competency; objectives; suggested instructional aids; a training outline (or lesson plan) for…

  20. Process for the production of sodium carbonate anhydrate

    NARCIS (Netherlands)

    Oosterhof, H.; Van Rosmalen, G.M.; Witkamp, G.J.; De Graauw, J.

    2000-01-01

    The invention is directed to a process for the production of sodium carbonate-anhydrate having a bulk density of at least 800 kg/m<3>, said process comprising: providing a suspension of solid sodium carbonate and/or solid sodium bicarbonate and/or solid double salts at least comprising one of sodium

  1. EDITORIAL: Non-polar and semipolar nitride semiconductors Non-polar and semipolar nitride semiconductors

    Science.gov (United States)

    Han, Jung; Kneissl, Michael

    2012-02-01

    Throughout the history of group-III-nitride materials and devices, scientific breakthroughs and technological advances have gone hand-in-hand. In the late 1980s and early 1990s, the discovery of the nucleation of smooth (0001) GaN films on c-plane sapphire and the activation of p-dopants in GaN led very quickly to the realization of high-brightness blue and green LEDs, followed by the first demonstration of GaN-based violet laser diodes in the mid 1990s. Today, blue InGaN LEDs boast record external quantum efficiencies exceeding 80% and the emission wavelength of the InGaN-based laser diode has been pushed into the green spectral range. Although these tremenduous advances have already spurred multi-billion dollar industries, there are still a number of scientific questions and technological issues that are unanswered. One key challenge is related to the polar nature of the III-nitride wurtzite crystal. Until a decade ago all research activities had almost exclusively concentrated on (0001)-oriented polar GaN layers and heterostructures. Although the device characteristics seem excellent, the strong polarization fields at GaN heterointerfaces can lead to a significant deterioration of the device performance. Triggered by the first demonstration non-polar GaN quantum wells grown on LiAlO2 by Waltereit and colleagues in 2000, impressive advances in the area of non-polar and semipolar nitride semiconductors and devices have been achieved. Today, a large variety of heterostructures free of polarization fields and exhibiting exceptional electronic and optical properties have been demonstrated, and the fundamental understanding of polar, semipolar and non-polar nitrides has made significant leaps forward. The contributions in this Semiconductor Science and Technology special issue on non-polar and semipolar nitride semiconductors provide an impressive and up-to-date cross-section of all areas of research and device physics in this field. The articles cover a wide range of

  2. 49 CFR 173.195 - Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen cyanide, anhydrous, stabilized... Hazardous Materials Other Than Class 1 and Class 7 § 173.195 Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution). (a) Hydrogen cyanide, anhydrous, stabilized, must be packed in...

  3. Anhydrous polymer-based coating with sustainable controlled release functionality for facile, efficacious impregnation, and delivery of antimicrobial peptides.

    Science.gov (United States)

    Lim, Kaiyang; Saravanan, Rathi; Chong, Kelvin K L; Goh, Sharon H M; Chua, Ray R Y; Tambyah, Paul A; Chang, Matthew W; Kline, Kimberly A; Leong, Susanna S J

    2018-04-17

    Anhydrous polymers are actively explored as alternative materials to overcome limitations of conventional hydrogel-based antibacterial coating. However, the requirement for strong organic solvent in polymerization reactions often necessitates extra protection steps for encapsulation of target biomolecules, lowering encapsulation efficiency, and increasing process complexity. This study reports a novel coating strategy that allows direct solvation and encapsulation of antimicrobial peptides (HHC36) into anhydrous polycaprolactone (PCL) polymer-based dual layer coating. A thin 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) film is layered onto the peptide-impregnated PCL as a diffusion barrier, to modulate and enhance release kinetics. The impregnated peptides are eventually released in a controlled fashion. The use of 2,2,2-trifluoroethanol (TFE), as polymerization and solvation medium, induces the impregnated peptides to adopt highly stable turned conformation, conserving peptide integrity, and functionality during both encapsulation and subsequent release processes. The dual layer coating showed sustained antibacterial functionality, lasting for 14 days. In vivo assessment using an experimental mouse wounding model demonstrated good biocompatibility and significant antimicrobial efficacy of the coating under physiological conditions. The coating was translated onto silicone urinary catheters and showed promising antibacterial efficacy, even outperforming commercial silver-based Dover cather. This anhydrous polymer-based platform holds immense potential as an effective antibacterial coating to prevent clinical device-associated infections. The simplicity of the coating process enhances its industrial viability. © 2018 Wiley Periodicals, Inc.

  4. Glass transition of anhydrous starch by fast scanning calorimetry.

    Science.gov (United States)

    Monnier, Xavier; Maigret, Jean-Eudes; Lourdin, Denis; Saiter, Allisson

    2017-10-01

    By means of fast scanning calorimetry, the glass transition of anhydrous amorphous starch has been measured. With a scanning rate of 2000Ks -1 , thermal degradation of starch prior to the glass transition has been inhibited. To certify the glass transition measurement, structural relaxation of the glassy state has been investigated through physical aging as well as the concept of limiting fictive temperature. In both cases, characteristic enthalpy recovery peaks related to the structural relaxation of the glass have been observed. Thermal lag corrections based on the comparison of glass transition temperatures measured by means of differential and fast scanning calorimetry have been proposed. The complementary investigations give an anhydrous amorphous starch glass transition temperature of 312±7°C. This estimation correlates with previous extrapolation performed on hydrated starches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Harvesting Water from Air: Using Anhydrous Salt with Sunlight

    KAUST Repository

    Li, Renyuan

    2018-04-02

    Atmospheric water is abundant alternative water resource, equivalent to 6 times of water in all rivers on Earth. This work screens 14 common anhydrous and hydrated salt couples in terms of their physical and chemical stability, water vapor harvesting and release capacity under relevant application scenarios. Among the salts screened, copper chloride (CuCl2), copper sulfate (CuSO4) and magnesium sulfate (MgSO4) distinguish themselves and are further made into bi-layer water collection devices, with the top layer being photothermal layer while the bottom layer being salt-loaded fibrous membrane. The water collection devices are capable of capturing water vapor out of the air with low relative humidity (down to 15 %) and releasing water under regular and even weakened sunlight (i.e. 0.7 kW/m2). The work shines light on the potential use of anhydrous salt towards producing drinking water in water scarce regions.

  6. Process for the production of sodium carbonate anhydrate

    OpenAIRE

    Oosterhof, H.; Van Rosmalen, G.M.; Witkamp, G.J.; De Graauw, J.

    2000-01-01

    The invention is directed to a process for the production of sodium carbonate-anhydrate having a bulk density of at least 800 kg/m, said process comprising: providing a suspension of solid sodium carbonate and/or solid sodium bicarbonate and/or solid double salts at least comprising one of sodium carbonate and sodium bicarbonate, in a mixture containing water and an organic, water miscible or partly water miscible solvent, which solvent influences the transition temperature below which sodium...

  7. Dry fumes purifying system using anhydrous baking soda; Procede chimique d`epuration des fumees au bicarbonate de soude anhydre

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1998-04-01

    UNISYSTEMS has developed the industrial implementation of the chemical process using anhydrous backing soda, patented by SOLVAY, for purifying fumes containing inorganic salts and sulphur oxides as polluting agents. The system can be applied to industrial processes releasing this type of polluting agents in the fumes at a temperature over 160 deg C, as it is specially indicated in purifying fumes coming from ceramic firing kilns. (authors)

  8. Efficiency droop in nonpolar InGaN quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Schade, Lukas; Schwarz, Ulrich [Fraunhofer Institut fuer Angewandte Festkoerperphysik (IAF), Freiburg im Breisgau (Germany); Institut fuer Mikrosystemtechnik (IMTEK), Universitaet Freiburg, Freiburg im Breisgau (Germany); Wernicke, Tim; Rass, Jens; Ploch, Simon [Institut fuer Festkoerperphysik, Technische Universitaet Berlin (Germany); Weyers, Markus [Ferdinand-Braun-Institut (FBH), Berlin (Germany); Kneissl, Michael [Institut fuer Festkoerperphysik, Technische Universitaet Berlin (Germany); Ferdinand-Braun-Institut (FBH), Berlin (Germany)

    2012-07-01

    InGaN quantum wells (QWs) exhibit a decline of the internal efficiency at high charge carrier excitation. This has been observed for polar as well as for semipolar and nonpolar oriented QWs. Polar stands for the (0001) growth direction with strong piezoelectric fields. Due to the vanishing fields, the orthogonal growth directions (a or m) are called nonpolar, while all directions between are merged as semipolar orientations. In contrast to the polar and many semipolar QWs, nonpolar InGaN QWs provide a special property: optical polarization of the radiative transitions, which is a result of the anisotropic strain within pseudomorphic grown nonpolar QWs. Using this property, the broadened effective emission can be resolved into two fundamental transitions. They are spectrally separated by a defined energy which corresponds to the energy distance of the valence subbands. We studied nonpolar InGaN/InGaN Multi-QWs grown on low defect density GaN substrates with a setup for confocal microscopy. To reach high excitation densities of charge carriers, we use either a combination of an UV laser and highly focusing objectives or an electric pulse generator. The emission is spectrally analysed and compared to established models.

  9. Thermal decomposition of anhydrous zinc and cadmium salicylates

    International Nuclear Information System (INIS)

    Kharitonov, Yu.Ya.; Tujebakhova, Z.K.

    1984-01-01

    On the basis of studying thermograms, thermogravigrams, IR absorption spectra, X-rayograms of anhydrous znc and cadmium salicylate complexes of the M(HSal) 2 composition, (where M=Zn, Cd; HSal is an anion of once deprotonated salicyclic acid H 2 Sal) and products of their thermal transformations, the processes are characterized of stage-by-stage thermal decomposition of these compounds under continuous heating in the air from room temperature to approximately 1000 deg C. It is shown that the Cd(HSal) 2 pyrolysis proceeds with the formation of CdSal at 170-250 deg C and CdO - at 320-460 deg C

  10. Crystallo-chemistry of boric anhydride and of anhydrous borates

    International Nuclear Information System (INIS)

    Bernardin, Jacques

    1968-01-01

    After an overview of various aspects related to the atomic structure of boron and of its three-bind and four-bind compounds, this report briefly presents the different forms of boric anhydride (in solid, liquid, glassy and gaseous state), presents and comments the structure of these different forms, and addresses the molten boric anhydride which is used as oxide solvent. The next part addresses the structure of anhydrous borates. It presents some generalities on their structure, and describes examples of known structures: dimers, trimers, polymers with a degree higher than three like calcium metaborate, caesium tri-borate, lithium tetraborate, or potassium pentaborate

  11. A New Thickener for CO2 Anhydrous Fracturing Fluid

    Directory of Open Access Journals (Sweden)

    Zhang Jian

    2015-01-01

    Full Text Available CO2 dry fracturing technology is well-known for its advantages. Little water is used in this technology, which is able to ease the pressure of consumption on water resources. Many abroad theoretical researches, laboratory experiments and field tests have been taken to explore the yield mechanism, the adaptability and the technology of pure liquid CO2 fracturing. These achievements have been applied to a variety of reservoirs transformation and improven the effectiveness of stimulation treatment in a degree. The researches and studies in the domestic didn’t get popular until recent years. Thus, this article firstly introduces the main development and application about pure CO2 anhydrous fracturing technology, and sums up the effect and evaluation of its fluid through application examples both in the domestic and abroad. However, although this technology has many excellent qualities, but systematic studies indicate that its proppant-carrying capacity is less competitive because of the low viscosity of pure CO2 liquid and other reasons. In a consequence, it is necessary to develop an appropriate thickener for CO2 anhydrous fracturing fluid to improve its carrying capacity. Then this article describes some studies of previous scholars about CO2 thickener. Then we put forward our own research ideas and transform it into actual experiments. Thanks to the valid performances of these tests, we successfully develop a thickener X and cosolvent B.

  12. Anhydrous crystals of DNA bases are wide gap semiconductors.

    Science.gov (United States)

    Maia, F F; Freire, V N; Caetano, E W S; Azevedo, D L; Sales, F A M; Albuquerque, E L

    2011-05-07

    We present the structural, electronic, and optical properties of anhydrous crystals of DNA nucleobases (guanine, adenine, cytosine, and thymine) found after DFT (Density Functional Theory) calculations within the local density approximation, as well as experimental measurements of optical absorption for powders of these crystals. Guanine and cytosine (adenine and thymine) anhydrous crystals are predicted from the DFT simulations to be direct (indirect) band gap semiconductors, with values 2.68 eV and 3.30 eV (2.83 eV and 3.22 eV), respectively, while the experimentally estimated band gaps we have measured are 3.83 eV and 3.84 eV (3.89 eV and 4.07 eV), in the same order. The electronic effective masses we have obtained at band extremes show that, at low temperatures, these crystals behave like wide gap semiconductors for electrons moving along the nucleobases stacking direction, while the hole transport are somewhat limited. Lastly, the calculated electronic dielectric functions of DNA nucleobases crystals in the parallel and perpendicular directions to the stacking planes exhibit a high degree of anisotropy (except cytosine), in agreement with published experimental results.

  13. Long-Wavelength Phonon Scattering in Nonpolar Semiconductors

    DEFF Research Database (Denmark)

    Lawætz, Peter

    1969-01-01

    The long-wavelength acoustic- and optical-phonon scattering of carriers in nonpolar semiconductors is considered from a general point of view. The deformation-potential approximation is defined and it is shown that long-range electrostatic forces give a nontrivial correction to the scattering...... of the very-short-range nature of interactions in a covalent semiconductor....

  14. Structural basis for the transformation pathways of the sodium naproxen anhydrate-hydrate system

    DEFF Research Database (Denmark)

    Bond, Andrew; Cornett, Claus; Larsen, Flemming Hofmann

    2014-01-01

    to the monohydrate (MH) and anhydrate (AH) structures, provide a basis to rationalize the observed transformation pathways in the sodium (S)-naproxen anhydrate-hydrate system. All structures contain Na(+)/carboxylate/H2O sections, alternating with sections containing the naproxen molecules. The structure of DH...

  15. Influence of Fe content on the creep properties of olivine under anhydrous and hydrous conditions

    Science.gov (United States)

    Trimmer, M. B.; Zhao, Y.; Zimmerman, M. E.; Kohlstedt, D. L.

    2007-12-01

    High-temperature, high-pressure compressive creep experiments were performed on both wet and dry aggregates of Fa75 in a gas-medium deformation apparatus. The results from these experiments are compared with those for San Carlos olivine, Fa10, and our previous results on Fa30 and Fa50 in order to provide a basis for comparing convection models for the mantle of Earth with those for the more iron-rich mantle of Mars. Samples were fabricated from powders of Fa75 that were synthesized from mixtures of Fe2O3 and SiO2 combined with San Carlos olivine. The Fa75 powders were cold-pressed into Fe capsules and then hot-pressed at 300 MPa, 1473 K for 3 h. The average grain size of the resultant hot-pressed samples was ~40 μm. For experiments under hydrous conditions, three drops of deionized water were added before sealing the sample within telescoping Fe cans for deformation. Water bubbles were present both within olivine grains and along grain boundaries, demonstrating that the samples were water-saturated. Triaxial compressive creep experiments were carried out in a servo-controlled, internally heated gas-medium apparatus at 50 K intervals between 1273 and 1423 K and a confining pressure of 300 MPa with differential stress of 10 to 300 MPa. For each sample, creep tests were performed at several differential stresses at a constant temperature to determine the stress exponent or at several temperatures to determine the activation energy for creep. Under anhydrous conditions the viscosity of samples of Fa75 is more than a factor of 10 lower than the viscosity of Fa50. Previous experiments showed a similar relationship between Fa50 and Fa30 and Fa30 and Fa10. Under hydrous conditions the viscosity of samples of Fa75 are about a factor of 5 lower than the viscosity of Fa50, which is less than that observed between Fa50 and Fa30 or Fa30 and Fa10. The viscosity of a sample of a specific Fe:Mg ratio deformed under hydrous conditions is a factor of 10 lower than its counterpart

  16. Preparation and characterization of ABS/anhydrous cobalt chloride composites

    Science.gov (United States)

    Shao, Chengli; Shang, Peng; Mao, Yapeng; Li, Qiuying; Wu, Chifei

    2018-01-01

    Anhydrous cobalt chloride (CoCl2) particles filled acrylonitrile-butadiene-styrene (ABS) composites were successfully prepared and investigated. A strong interfacial interaction between CoCl2 particles and ABS matrix was generated by heat pressing at 190 °C for 15 min. SEM results demonstrated that the particles were dispersed uniformly in the matrix. Fourier transform infrared, x-ray photoelectron spectroscopy and electron spin resonance were used for the investigation of the coordination reaction. The interfacial interaction resulted from a solid-state coordination reaction between nitrile groups (-CN) and cobalt ions (Co2+), leading to an increase in mechanical properties and glass transition temperature. Moreover, heat deflection temperatures were measured and proved to achieve an improvement of 30.6 °C when the CoCl2 content was 7 wt%.

  17. Comparison of Intermolecular Forces in Anhydrous Sorbitol and Solvent Cocrystals.

    Science.gov (United States)

    Dierks, Teresa M; Korter, Timothy M

    2017-08-03

    The hygroscopicity of solid sorbitol is important for its utilization as a sweetener in the pharmaceutical and food industries. The molecular foundations of sorbitol hydration characteristics are explored here using two solvated cocrystals, sorbitol-water and sorbitol-pyridine. In this work, solid-state density functional theory and terahertz time-domain spectroscopy were used to evaluate the relative stabilities of these cocrystals as compared to anhydrous sorbitol in terms of conformational and cohesive energies. The modification of the hydrogen-bonding network in crystalline sorbitol by solvent molecules gives new insight into the origins of the notable stability of sorbitol-water as compared to similar solids such as mannitol-water. In particular, the energy analysis reveals that the relative instability of the mannitol hydrate is based primarily in the lack of water-water interactions which provide considerable stabilization in the sorbitol-water crystal.

  18. Anhydrous proton conductor based on composites of PEO and ATMP

    Energy Technology Data Exchange (ETDEWEB)

    Sun Baoying [Key Lab of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084 (China); Qiu Xinping, E-mail: qiuxp@tsinghua.edu.c [Key Lab of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084 (China); Zhu Wentao [Key Lab of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084 (China)

    2011-04-15

    A new type anhydrous PEM material based on Poly (ethylene oxide) (PEO)/Amino Trimethylene Phosphonic Acid (ATMP) composite was prepared. In this study, PEO assumed to 'grab' protons via hydrogen bond between PEO and ATMP. Based on this point, the PEO/ATMP composites were prepared firstly as the preliminary study to verify this proton conducting system. Then, PVDF was added to enhance the membrane's stability. The PVDF/PEO/ATMP composite membranes were thermally stable up to 200 {sup o}C in the studied composition ranges. The membrane had relatively compact structure by SEM images. Proton conductivity of 59% PVDF/29% PEO/12% ATMP was up to 6.71 x 10 {sup -3} S cm{sup -1} at 86 {sup o}C after doping with 7.9 wt% phosphoric acid without extra humidification.

  19. Anhydrous proton conductor based on composites of PEO and ATMP

    International Nuclear Information System (INIS)

    Sun Baoying; Qiu Xinping; Zhu Wentao

    2011-01-01

    A new type anhydrous PEM material based on Poly (ethylene oxide) (PEO)/Amino Trimethylene Phosphonic Acid (ATMP) composite was prepared. In this study, PEO assumed to 'grab' protons via hydrogen bond between PEO and ATMP. Based on this point, the PEO/ATMP composites were prepared firstly as the preliminary study to verify this proton conducting system. Then, PVDF was added to enhance the membrane's stability. The PVDF/PEO/ATMP composite membranes were thermally stable up to 200 o C in the studied composition ranges. The membrane had relatively compact structure by SEM images. Proton conductivity of 59% PVDF/29% PEO/12% ATMP was up to 6.71 x 10 -3 S cm -1 at 86 o C after doping with 7.9 wt% phosphoric acid without extra humidification.

  20. Photophysical properties of coumarin-120: Unusual behavior in nonpolar solvents

    International Nuclear Information System (INIS)

    Pal, Haridas; Nad, Sanjukta; Kumbhakar, Manoj

    2003-01-01

    Photophysical properties of coumarin-120 (C120; 7-amino-4-methyl-1,2-benzopyrone) dye have been investigated in different solvents using steady-state and time-resolved fluorescence and picosecond laser flash photolysis (LFP) and nanosecond pulse radiolysis (PR) techniques. C120 shows unusual photophysical properties in nonpolar solvents compared to those in other solvents of moderate to higher polarities. Where the Stokes shifts (Δν-bar=ν-bar abs -ν-bar fl ), fluorescence quantum yields (Φ f ), and fluorescence lifetimes (τ f ) show more or less linear correlation with the solvent polarity function Δf={(ε-1)/(2ε+1)-(n 2 -1)/(2n 2 +1)}, all these parameters are unusually lower in nonpolar solvents. Unlike in other solvents, both Φ f and τ f in nonpolar solvents are also strongly temperature dependent. It is indicated that the excited singlet (S 1 ) state of C120 undergoes a fast activation-controlled nonradiative deexcitation in nonpolar solvents, which is absent in all other solvents. LFP and PR studies indicate that the intersystem crossing process is negligible for the present dye in all the solvents studied. Photophysical behavior of C120 in nonpolar solvent has been rationalized assuming that in these solvents the dye exists in a nonpolar structure, with its 7-NH 2 group in a pyramidal configuration. In this structure, since the 7-NH 2 group is bonded to the 1,2-benzopyrone moiety by a single bond, the former group can undergo a fast flip-flop motion, which in effect causes the fast nonradiative deexcitation of the dye excited state. In moderate to higher polarity solvents, it is indicated that the dye exists in an intramolecular charge-transfer structure, where the bond between 7-NH 2 group and the 1,2-benzopyrone moiety attains substantial double bond character. In this structure, the flip-flop motion of the 7-NH 2 group is highly restricted and thus there is no fast nonradiative deexcitation process for the excited dye

  1. Charging and Screening in Nonpolar Solutions of Nonionizable Surfactants

    Science.gov (United States)

    Behrens, Sven

    2010-03-01

    Nonpolar liquids do not easily accommodate electric charges, but surfactant additives are often found to dramatically increase the solution conductivity and promote surface charging of suspended colloid particles. Such surfactant-mediated electrostatic effects have been associated with equilibrium charge fluctuations among reverse surfactant micelles and in some cases with the statistically rare ionization of individual surfactant molecules. Here we present experimental evidence that even surfactants without any ionizable group can mediate charging and charge screening in nonpolar oils, and that they can do so at surfactant concentrations well below the critical micelle concentration (cmc). Precision conductometry, light scattering, and Karl-Fischer titration of sorbitan oleate solutions in hexane, paired with electrophoretic mobility measurements on suspended polymer particles, reveal a distinctly electrostatic action of the surfactant. We interpret our observations in terms of a charge fluctuation model and argue that the observed charging processes are likely facilitated, but not limited, by the presence of ionizable impurities.

  2. Nanoencapsulation of Fullerenes in Organic Structures with Nonpolar Cavities

    International Nuclear Information System (INIS)

    Murthy, C. N.

    2005-01-01

    The formation of supramolecular structures, assemblies, and arrays held together by weak intermolecular interactions and non-covalent binding mimicking natural processes has been used in applications being anticipated in nanotechnology, biotechnology and the emerging field of nanomedicine. Encapsulation of C 60 fullerene by cyclic molecules like cyclodextrins and calixarenes has potential for a number of applications. Similarly, biomolecules like lysozyme also have been shown to encapsulate C 60 fullerene. This poster article reports the recent trends and the results obtained in the nanoencapsulation of fullerenes by biomolecules containing nonpolar cavities. Lysozyme was chosen as the model biomolecule and it was observed that there is no covalent bond formed between the bimolecule and the C 60 fullerene. This was confirmed from fluorescence energy transfer studies. UV-Vis studies further supported this observation that it is possible to selectively remove the C 60 fullerene from the nonpolar cavity. This behavior has potential in biomedical applications

  3. Photonic Crystal Polarizing and Non-Polarizing Beam Splitters

    International Nuclear Information System (INIS)

    Chun-Ying, Guan; Jin-Hui, Shi; Li-Boo, Yuan

    2008-01-01

    A polarizing beam splitter (PBS) and a non-polarizing beam splitter (NPBS) based on a photonic crystal (PC) directional coupler are demonstrated. The photonic crystal directional coupler consists of a hexagonal lattice of dielectric pillars in air and has a complete photonic band gap. The photonic band structure and the band gap map are calculated using the plane wave expansion (PWE) method. The splitting properties of the splitter are investigated numerically using the finite difference time domain (FDTD) method

  4. Automated thin-film analyses of anhydrous interplanetary dust particles in the analytical electron microscope

    Science.gov (United States)

    Bradley, J. P.; Germani, M. S.; Brownlee, D. E.

    1989-01-01

    An AEM apparatus equipped with digital beam control has obtained quantitative point-count analyses of thin sections taken from eight anhydrous chondritic interplanetary dust particles (IDPs); between 200 and 500 X-ray analyses were collected from each thin section and analyzed for Mg, Al, Si, S, Ca, Cr, Mn, Fe, and Ni. Two types of anhydrous chondritic aggregates were observed in the eight IDPs: one highly porous, the other less so. The eight anhydrous IDPs are characterizable as mixtures of fine- and coarse-grained aggregates, large mineral grains, glass, and carbonaceous materials. Their elemental concentrations follow those of solar abundances, suggesting that they are unperturbed by aqueous alteration.

  5. Interaction of alcohols with the anhydrous silico-12-molybdic acid

    International Nuclear Information System (INIS)

    Pinchuk, I.N.; Chuvaev, V.F.; Ovchinnikova, N.S.; Zhuravlev, L.T.; Spitsyn, V.I.

    1984-01-01

    A study was made on interaction of methanol, ethanol and isopropanol with silico-12-molybdic acid (H 4 SiMo 12 O 40 (SMA). It was revealed that anhydrous SMA at room temperature adds a sufficient amount of alcohol from gaseous phase with formation of solvates of the following compositions: H 4 SiMo 12 O 40 x3CH 3 OH, H 4 SiMo 12 O 40 x5C 2 H 5 OH and H 4 SiMo 12 O 40 x3C 3 H 7 OH. Thermal decomposition of SMA solvates was studied and the mechanism of solid-phase heteropolyacid interaction with alcohols was suggested. Temperature ranges of separate catalytic and redox processes were established. Specificity of activity and peculiarities of heteropolyacid transformation in the course of reaction were investigated. It was shown that formation of deprotonated phases of SiMosub(12)Osub(38-y/2) or Csub(n)SiMosub(12)Osub(38-x) type during SMA interaction with alcohol can't be probably reduced to the simple succession of reduction and dehydration reactions

  6. Transport of anhydrous ammoniac - risk assessment; Le transport de l'ammoniac anhydre - analyse et estimation des risques: rapport de synthese

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, S; Degrange, J P; Hubert, P; Pages, P; Lamblin, J

    1989-12-01

    This risk analysis of anhydrous ammonia transport in France was done within a study initiated by the Department of dangerous goods of the Ministry of transport. The study deals with the road and rail transportation of bulk anhydrous ammonia. After analysis of transport system and traffic, the transport accident risks are estimated, as well as their distribution on the French territory. Finally after a synthesis of results, a number of safety measures to be undertaken were identified. This is a joint study of SMC-CEPN, with a specific role of SEMA-METRA-CONSEIL concerning the traffic frequency, and the center for risk evaluation concerning nuclear safety.

  7. Study of alkaline-earth element complexes in anhydrous acetic acid

    International Nuclear Information System (INIS)

    Petit, N.

    1968-10-01

    We have studied the complexes of alkaline-earth elements in anhydrous acetic acid. Using glass-electrode potentiometry we have studied the titration of alkaline earth acetates with perchloric acid which is the strongest acid in anhydrous acetic acid. These titrations have shown that the basic strength of these acetates increases as follows: Mg 4 ); the mixed acetate-acid sulfate complex of barium: Ba (OAc)(HSO 4 ); the mixed acetate-chloride of barium: Ba (OAc)(Cl). (author) [fr

  8. Dehydration Behaviour of Borax Pentahydrate to Anhydrous Borax by Multi-Stage Heating in a Fluidized

    OpenAIRE

    ŞAHİN, Ömer

    2002-01-01

    In order to optimize the anhydrous borax process in a fluidized bed calcinator, it is absolutely necessary to study the dehydration behaviour of borax pentahydrate. It was found that the basic feature of the dehydration of borax pentahydrate to anhydrous borax is concerned with the conditions employed. The bulk density and sodium borate content of the end product were determined to be a function of number of stages of temperature of the dehydration period in the fluidized bed. It...

  9. The Effect of Compaction Force on the Transition to Hydrate of Anhydrous Aripiprazole.

    Science.gov (United States)

    Togo, Taichiro; Taniguchi, Toshiya; Nakata, Yoshitaka

    2018-01-01

    Aripiprazole (APZ) is used to treat schizophrenia and is administered as a tablet containing the anhydrous form of APZ. In this study, the effect of compaction force on the crystal form transition was investigated. The crystalline state was observed by X-ray diffraction (XRD). APZ Anhydrous Form II was compacted into tablets. The XRD intensity of anhydrous APZ became lower with higher compressive force. The degree of crystallinity decreased with the compaction force. The powder and the compacted tablets of anhydrous APZ were stored for one week under 60°C and 75% relative humidity. The powder showed no crystal form transition after storage. For the tablets, however, XRD peaks of APZ hydrate were observed after storage. The tablets compacted with higher force showed the higher XRD diffraction intensity of hydrate form. We concluded that the crystallinity reduction of APZ Anhydrous Form II by compaction caused and accelerated the transition to hydrate under high temperature and humidity conditions. In order to manufacture crystallographically stable tablets containing anhydrous APZ, it is important to prevent this crystallinity reduction during compaction.

  10. Water in Nominally Anhydrous Minerals from Nakhlites and Shergottites

    Science.gov (United States)

    Peslier, Anne H.

    2013-01-01

    Estimating the amount of water in the interior of terrestrial planets has tremendous implications on our understanding of solar nebula evolution, planet formation and geological history, and extraterrestrial volcanism. Mars has been a recent focus of such enquiry with complementary datasets from spacecrafts, rovers and martian meteorite studies. In planetary interiors, water can be dissolved in fluids or melts and hydrous phases, but can also be locked as protons attached to structural oxygen in lattice defects in nominally anhydrous minerals (NAM) such as olivine, pyroxene, or feldspar [1-3]. Measuring water in Martian meteorite NAM is challenging because the minerals are fragile and riddled with fractures from impact processes that makes them break apart during sample processing. Moreover, curing the sample in epoxy causes problems for the two main water analysis techniques, Fourier transform infrared spectrometry (FTIR) and secondary ionization mass spectrometry (SIMS). Measurements to date have resulted in a heated debate on how much water the mantle of Mars contains. SIMS studies of NAM [4], amphiboles [5], and apatites [6-8] from Martian meteorites report finding enough water in these phases to infer that the martian mantle is as hydrous as that of the Earth. On the other hand, a SIMS study of glass in olivine melt inclusions from shergottites concludes that the Martian mantle is much drier [9]. The latter interpretation is also supported by the fact that most martian hydrous minerals generally have the relevant sites filled with Cl and F instead of H [10,11]. As for experimental results, martian basalt compositions can be reproduced using water as well as Cl in the parent melts [12,13]. Here FTIR is used to measure water in martian meteorite minerals in order to constrain the origin of the distribution of water in martian meteorite phases.

  11. Electrophoretic Retardation of Colloidal Particles in Nonpolar Liquids

    Directory of Open Access Journals (Sweden)

    Filip Strubbe

    2013-04-01

    Full Text Available We have measured the electrophoretic mobility of single, optically trapped colloidal particles, while gradually depleting the co-ions and counterions in the liquid around the particle by applying a dc voltage. This is achieved in a nonpolar liquid, where charged reverse micelles act as co-ions and counterions. By increasing the dc voltage, the mobility first increases when the concentrations of co-ions and counterions near the particle start to decrease. At sufficiently high dc voltage (around 2 V, the mobility reaches a saturation value when the co-ions and counterions are fully separated. The increase in mobility is larger when the equilibrium ionic strength is higher. The dependence of the experimental data on the equilibrium ionic strength and on the applied voltage is in good agreement with the standard theory of electrophoretic retardation, assuming that the bare particle charge remains constant. This method is useful for studying the electrophoretic retardation effect and charging mechanisms for nonpolar colloids, and it sheds light on previously unexplained particle acceleration in electronic ink devices.

  12. Chemical characterization by GC-MS and phytotoxic potential of non-polar and polar fractions of seeds of Dioteryx odorata (Aubl. Willd. from Venezuelan regions

    Directory of Open Access Journals (Sweden)

    Alberto de J. Oliveros-Bastidas

    2013-01-01

    Full Text Available Dipteryx odorata (Aubl. Willd. is a tall arboreal species native to Central and Northern South America. This paper describes the chemical characterization and phytotoxic potential of polar and non-polar extracts from D. odorata seeds. Structural determinations were accomplished by chemical derivatization and analyzed by GC/MS. The chemical composition of the non-polar fraction (hexane and dichloromethane presented fatty acids as major constituent. Medium polar and polar fractions (ethyl acetate and ethanol: water contained carboxylic acid and high 6,7-Dyhidroxycoumarin-β-D-glucopyranoside content, not previously reported for seeds of D. odorata. Extracts showed a significant level of phytotoxic activity, correlated to the content of coumarin derivatives, predominantly in the polar fraction.

  13. Synthesis of fertilizers nitrogen and 15N-enriched. Pt. I. Production of enriched 15N-anhydrous ammonia

    International Nuclear Information System (INIS)

    Bendassolli, J.A.; Mortatti, J.; Trivelin, P.C.O.; Victoria, R.L.

    1988-01-01

    The results of 15 N-anhydrous ammonia production through reaction between 15 N-enriched ammonium sulphate and sodium hidroxide are reported. Influence of the reaction temperature, carrier gas flow, reaction time and mass of ammonium sulphate on the production of anhydrous ammonia were studied. Analyses for the cost of production of 5% atoms in 15 N-enriched anhydrous ammonia were made. (M.A.C.) [pt

  14. Molecular design for nonpolar chiral-axial quadratic nonlinear optics

    Science.gov (United States)

    Wiggers, Gregory A.

    In this thesis the hyperpolarizability of various multi-dimensional molecules is studied theoretically/computationally, with particular focus on the second-rank Kleinman-disallowed (KD) component of the hyperpolarizability. This component, which transforms as a second-rank traceless symmetric tensor, could be utilized in certain chiral-axial molecular alignment schemes to produce a bulk response. Nonpolar chiral-axial systems have been proposed in contrast to polar media, which utilize the vector component of the molecular hyperpolarizability and require parallel alignment of the molecular dipoles. Such parallel alignment of dipoles must be "frozen in" in order to overcome the natural tendency for dipoles to align anti-parallel. This limits the density of chromophores that can be loaded into a polar material. Nonpolar materials do not have such limits in theory. The two geometric classes of molecules that can most easily be incorporated into nonpolar chiral-uniaxial materials are propeller-shaped (C3 or D3 symmetry) and Λ-shaped (C2v symmetry). This work describes efforts to design molecules within these classes that would be suitable for bulk NLO materials. The sum-over-states (SOS) expression is used to model the molecular hyperpolarizability, and quantum chemical calculations, along with linear absorption data (when available) provide the necessary parameters to evaluate truncated forms of the SOS expression. A host of chemical and geometric modifications will be considered in order to elucidate important structure/function relationships. Also, the SOS model will be tested in some cases when experimental measurements (via Kleinman-disallowed hyper-Rayleigh scattering) are available. While a majority of this work focuses on multi-dimensional molecules, a small section deals with the question of optimizing the hyperpolarizability of a one-dimensional system. It is suggested that the recently-proposed idea of "modulated conjugation" as a means for improving

  15. Pressure effects on electron reactions and mobility in nonpolar liquids

    International Nuclear Information System (INIS)

    Holroyd, R.A.; Nishikawa, Masaru

    2002-01-01

    High pressure studies have elucidated the mechanisms of both electron reactions and electron transport in nonpolar liquids and provided information about the partial molar volumes of ions and electrons. The very large volume changes associated with electron attachment reactions have been explained as due to electrostriction by the ions, calculated with a continuum model, but modified to include the formation of a glassy shell of solvent molecules around the ion. The mobilities of electrons in cases where the electron is trapped can now be understood by comparing the trap cavity volume with the volume of electrostriction of the solvent around the cavity. In cases where the electron is quasi-free the compressibility dependent potential fluctuations are shown to be important. The isothermal compressibility is concluded to be the single most important parameter determining the behavior of excess electrons in liquids

  16. Dielectric constant of polarizable, nonpolar fluids and suspensions

    International Nuclear Information System (INIS)

    Cichocki, B.; Felderhof, B.U.

    1988-01-01

    We study the dielectric constant of a polarizable, nonpolar fluid or suspension of spherical particles by use of a renormalized cluster expansion.The particles may have induced multipole moments of any order. We show that the Clausius-Mossotti formula results from a virtual overlap contribution. The corrections to the Clausius-Mossotti formula are expressed with the aid of a cluster expansion. The integrands of the cluster integrals are expressed in terms of two-body nodal connectors which incorporate all reflections between a pair of particles. We study the two- and three-body cluster integrals in some detail and show how these are related to the dielectric virial expansion and to the first term of the Kirkwood-Yvon expansion

  17. The Thermodynamics of Anion Complexation to Nonpolar Pockets.

    Science.gov (United States)

    Sullivan, Matthew R; Yao, Wei; Tang, Du; Ashbaugh, Henry S; Gibb, Bruce C

    2018-02-08

    The interactions between nonpolar surfaces and polarizable anions lie in a gray area between the hydrophobic and Hofmeister effects. To assess the affinity of these interactions, NMR and ITC were used to probe the thermodynamics of eight anions binding to four different hosts whose pockets each consist primarily of hydrocarbon. Two classes of host were examined: cavitands and cyclodextrins. For all hosts, anion affinity was found to follow the Hofmeister series, with associations ranging from 1.6-5.7 kcal mol -1 . Despite the fact that cavitand hosts 1 and 2 possess intrinsic negative electrostatic fields, it was determined that these more enveloping hosts generally bound anions more strongly. The observation that the four hosts each possess specific anion affinities that cannot be readily explained by their structures, points to the importance of counter cations and the solvation of the "empty" hosts, free guests, and host-guest complexes, in defining the affinity.

  18. Formation of a new crystalline form of anhydrous β-maltose by ethanol-mediated crystal transformation.

    Science.gov (United States)

    Verhoeven, Nicolas; Neoh, Tze Loon; Ohashi, Tetsuya; Furuta, Takeshi; Kurozumi, Sayaka; Yoshii, Hidefumi

    2012-04-01

    β-Maltose monohydrate was transformed into an anhydrous form by ethanol-mediated method under several temperatures with agitation. A new stable anhydrous form of β-maltose (Mβ(s)) was obtained, as substantiated by the X-ray diffraction patterns. Mβ(s) obtained by this method presented a fine porous structure, resulting in greater specific surface area compared to those of β-maltose monohydrate and anhydrous β-maltose obtained by vacuum drying (Mβ(h)). The crystal transformation presumably consisted of two steps: dehydration reaction from the hydrous to amorphous forms and crystal formation from the amorphous forms to the noble anhydrous form. The kinetics of these reactions were determined by thermal analysis using Jander's equation and Arrhenius plots. The overall activation energies of the dehydration reaction and the formation of anhydrous maltose were evaluated to be 100 and 90 kJ/mol, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Outcomes of curettage and anhydrous alcohol adjuvant for low-grade chondrosarcoma of long bone.

    Science.gov (United States)

    Kim, Wanlim; Han, Ilkyu; Kim, Eo Jin; Kang, Seungcheol; Kim, Han-Soo

    2015-06-01

    Low-grade chondrosarcoma of long bones can be treated successfully with extended intralesional curettage using adjuvants. However, there is no study reporting the use of anhydrous alcohol as an adjuvant in the treatment of low-grade chondrosarcoma. We asked (1) whether intralesional curettage and anhydrous alcohol adjuvant for low-grade chondrosarcoma is associated with good oncologic outcomes; and we report (2) the complications of the procedure. Thirty-six patients (13 men, 23 women) with a mean age of 46 years (range, 18-67 years) were treated for low-grade chondrosarcoma and followed up for a median of 62 months (range, 24-169 months). After intralesional curettage, and additional burring, anhydrous alcohol was used as an adjuvant therapy. At the time of last follow-up, there were no local recurrences or distant metastases. Six patients developed complications: 4 postoperative fractures (11%), 1 intra-articular loose body (3%) and 1 postoperative joint stiffness (3%). Anhydrous alcohol is a reasonable adjuvant for the curettage of low-grade chondrosarcoma of long bones. A long-term follow-up study is necessary, considering the slow biological progression of low-grade chondrosarcoma. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. 7 CFR 58.715 - Cream, plastic cream and anhydrous milkfat.

    Science.gov (United States)

    2010-01-01

    ... Service 1 Quality Specifications for Raw Material § 58.715 Cream, plastic cream and anhydrous milkfat. These food products shall be pasteurized, sweet, have a pleasing and desirable flavor and be free from objectionable flavors, and shall be obtained from milk which complies with the quality requirements as specified...

  1. Lean hydrous and anhydrous bioethanol combustion in spark ignition engine at idle

    International Nuclear Information System (INIS)

    Chuepeng, Sathaporn; Srisuwan, Sudecha; Tongroon, Manida

    2016-01-01

    Highlights: • Anhydrous ethanol burns fastest in uncalibrated engine at equal equivalence ratio. • The leaner hydrous ethanol combustion tends to elevate the COV in imep. • Hydrous ethanol consumption was 10% greater than anhydrous ethanol at ϕ = 0.67 limit. • Optimizing alternative fuel engine at idle for stability and emission is suggested. - Abstract: The applications of anhydrous bioethanol to substitute or replace gasoline fuel have shown to attain benefits in terms of engine thermal efficiency, power output and exhaust emissions from spark ignition engines. A hydrous bioethanol has also been gained more attention due to its energy and cost effectiveness. The main aim of this work is to minimize fuel quantity injected to the intake ports of a four-cylinder engine under idle condition. The engine running with hydrous ethanol undergoes within lean-burn condition as its combustion stability is analyzed using an engine indicating system. Coefficient of variation in indicated mean effective pressure is an indicator for combustion stability with hydrocarbon and carbon monoxide emission monitoring as a supplement. Anhydrous ethanol burns faster than hydrous ethanol and gasoline in the uncalibrated engine at the same fuel-to-air equivalence ratio under idle condition. The leaner hydrous ethanol combustion tends to elevate the coefficient of variation in indicated mean effective pressure. The experimental results have found that the engine consumes greater hydrous ethanol by 10% on mass basis compared with those of anhydrous ethanol at the lean limit of fuel-to-air equivalence ratio of 0.67. The results of exhaust gas analysis were compared with those predicted by chemical equilibrium analysis of the fuel-air combustion; the resemble trends were found. Calibrating the alternative fueled engine for fuel injection quantity should be accomplished at idle with combustion stability and emissions optimization.

  2. Ginzburg-Landau-type theory of nonpolarized spin superconductivity

    Science.gov (United States)

    Lv, Peng; Bao, Zhi-qiang; Guo, Ai-Min; Xie, X. C.; Sun, Qing-Feng

    2017-01-01

    Since the concept of spin superconductor was proposed, all the related studies concentrate on the spin-polarized case. Here, we generalize the study to the spin-non-polarized case. The free energy of nonpolarized spin superconductor is obtained, and Ginzburg-Landau-type equations are derived by using the variational method. These Ginzburg-Landau-type equations can be reduced to the spin-polarized case when the spin direction is fixed. Moreover, the expressions of super linear and angular spin currents inside the superconductor are derived. We demonstrate that the electric field induced by the super spin current is equal to the one induced by an equivalent charge obtained from the second Ginzburg-Landau-type equation, which shows self-consistency of our theory. By applying these Ginzburg-Landau-type equations, the effect of electric field on the superconductor is also studied. These results will help us get a better understanding of the spin superconductor and related topics such as the Bose-Einstein condensate of magnons and spin superfluidity.

  3. Density and Phase State of a Confined Nonpolar Fluid

    Science.gov (United States)

    Kienle, Daniel F.; Kuhl, Tonya L.

    2016-07-01

    Measurements of the mean refractive index of a spherelike nonpolar fluid, octamethytetracylclosiloxane (OMCTS), confined between mica sheets, demonstrate direct and conclusive experimental evidence of the absence of a first-order liquid-to-solid phase transition in the fluid when confined, which has been suggested to occur from previous experimental and simulation results. The results also show that the density remains constant throughout confinement, and that the fluid is incompressible. This, along with the observation of very large increases (many orders of magnitude) in viscosity during confinement from the literature, demonstrate that the molecular motion is limited by the confining wall and not the molecular packing. In addition, the recently developed refractive index profile correction method, which enables the structural perturbation inherent at a solid-liquid interface and that of a liquid in confinement to be determined independently, was used to show that there was no measurable excess or depleted mass of OMCTS near the mica surface in bulk films or confined films of only two molecular layers.

  4. Adsorption of polar, nonpolar, and substituted aromatics to colloidal graphene oxide nanoparticles

    NARCIS (Netherlands)

    Wang, Fang; Haftka, Joris J H; Sinnige, Theo L.; Hermens, Joop L M; Chen, Wei

    2014-01-01

    We conducted batch adsorption experiments to understand the adsorptive properties of colloidal graphene oxide nanoparticles (GONPs) for a range of environmentally relevant aromatics and substituted aromatics, including model nonpolar compounds (pyrene, phenanthrene, naphthalene, and

  5. Pectin/anhydrous dibasic calcium phosphate matrix tablets for in vitro controlled release of water-soluble drug.

    Science.gov (United States)

    Mamani, Pseidy Luz; Ruiz-Caro, Roberto; Veiga, María Dolores

    2015-10-15

    Different pectin/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed in order to obtain controlled release of a water-soluble drug (theophylline). Swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralized water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid), to characterize the matrix tablets. When the pectin/ADCP ratio was ≥0.26 (P1, P2, P3 and P4 tablets) a continuous swelling and low theophylline dissolution rate from the matrices were observed. So, pectin gel forming feature predominated over the ADCP properties, yielding pH-independent drug release behavior from these matrices. On the contrary, pectin/ADCP ratios ≤0.11 (P5 and P6 tablets) allowed to achieve drug dissolution pH dependent. Consequently, the suitable selection of the pectin/ADCP ratio will allow to tailor matrix tablets for controlled release of water-soluble drugs in a specific manner in the gastrointestinal tract. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Design technique for all-dielectric non-polarizing beam splitter plate

    Science.gov (United States)

    Rizea, A.

    2012-03-01

    There are many situations when, for the proper working, an opto-electronic device requiring optical components does not change the polarization state of light after a reflection, splitting or filtering. In this paper, a design for a non-polarizing beam splitter plate is proposed. Based on certain optical properties of homogeneous dielectric materials we will establish a reliable thin film package formula, excellent for the start of optimization to obtain a 20-nm bandwidth non-polarizing beam splitter.

  7. The influence of non-polar lipids on tear film dynamics

    KAUST Repository

    Bruna, M.

    2014-04-04

    © 2014 Cambridge University Press. In this paper we examine the effect that physiological non-polar lipids, residing on the surface of an aqueous tear film, have on the film evolution. In our model we track the evolution of the thickness of the non-polar lipid layer, the thickness of the aqueous layer and the concentration of polar lipids which reside at the interface between the two. We also utilise a force balance in the non-polar lipid layer in order to determine its velocity. We show how to obtain previous models in the literature from our model by making particular choices of the parameters. We see the formation of boundary layers in some of these submodels, across which the concentration of polar lipid and the non-polar lipid velocity and film thickness vary. We solve our model numerically for physically realistic parameter values, and we find that the evolution of the aqueous layer and the polar lipid layer are similar to that described by previous authors. However, there are interesting dynamics for the non-polar lipid layer. The effects of altering the key parameters are highlighted and discussed. In particular, we see that the Marangoni number plays a key role in determining how far over the eye the non-polar lipid spreads.

  8. Electroenzymatic Reactions With Oxygen on Laccase-Modified Electrodes in Anhydrous (Pure) Organic Solvent

    DEFF Research Database (Denmark)

    Yarapolov, A.; Shleev, S.; Zaitseva, E.

    2007-01-01

    in two different ways: (i) by studying the electroreduction of oxygen in anhydrous DMSO via a direct electron transfer mechanism without proton donors and (ii) by doing the same experiments in the presence of laccase substrates, which display in pure organic solvents both the properties of electron......The electroenzymatic reactions of Trametes hirsuta laccase in the pure organic solvent dimethyl sulfoxide (DMSO) have been investigated within the framework for potential use as a catalytic reaction scheme for oxygen reduction. The bioelectrochemical characteristics of laccase were investigated...... donors as well as the properties of weak acids. The results obtained with laccase in anhydrous DMSO were compared with those obtained previously in aqueous buffer. It was shown that in the absence of proton donors under oxygenated conditions, formation of superoxide anion radicals is prevented at bare...

  9. Anhydrous proton conducting composite membranes containing Nafion and triazole modified POSS

    International Nuclear Information System (INIS)

    Lei, M.; Wang, Y.G.; Zhang, F.F.; Huang, C.; Xu, X.; Zhang, R.; Fan, D.Y.

    2014-01-01

    Development of membrane electrolytes having reasonable proton conductivity and mechanical strength under anhydrous conditions is of great importance for proton exchange membrane fuel cells operated at elevated temperature. With the introduction of triazole modified polyhedral oligomeric silsesquioxanes (Tz-POSS) into Nafion membrane, the formed composite electrolytes exhibit improved mechanical properties compared to pristine Nafion membrane due to the well distribution of Tz-POSS inside the membrane. The anhydrous proton conductivity of the formed composite membranes increases initially with the increase in temperature, reaching about 0.02 Scm −1 at 140 °C. With further increase in temperature to about 150 °C, the composite membrane reaches its glass transition point above which the proton conductivity decreases dramatically. The performance of assembled single cell from composite membrane is slightly dependent on humidification conditions at 95 °C, reaching 0.45 V at 600 mAcm −2 using hydrogen and oxygen as reaction gases

  10. Method for application of nitrogen-15-labeled anhydrous ammonia to small plots

    International Nuclear Information System (INIS)

    Sanchez, C.A.; Blackmer, A.M.

    1987-01-01

    A method is described that permits precise application of anhydrous ammonia in bands to plots of the size often used in 15 N-tracer studies. This method involves placing a stainless-steel capillary tube in the soil where the ammonia is to be banded, attaching this tube to a cylinder of ammonia, and then pulling the tube through the soil with deposition of ammonia as an even band. The procedure has marked advantages over previously described methods because it can be used with mixtures of anhydrous ammonia and nitrification inhibitors and because the soil environment at the point of application is representative of the soil environment found when a conventional applicator is used

  11. Ab initio and DFT studies of the structure and vibrational spectra of anhydrous caffeine

    Science.gov (United States)

    Srivastava, Santosh K.; Singh, Vipin B.

    2013-11-01

    Vibrational spectra and molecular structure of anhydrous caffeine have been systematically investigated by second order Moller-Plesset (MP2) perturbation theory and density functional theory (DFT) calculations. Vibrational assignments have been made and many previous ambiguous assignments in IR and Raman spectra are amended. The calculated DFT frequencies and intensities at B3LYP/6-311++G(2d,2p) level, were found to be in better agreement with the experimental values. It was found that DFT with B3LYP functional predicts harmonic vibrational wave numbers more close to experimentally observed value when it was performed on MP2 optimized geometry rather than DFT geometry. The calculated TD-DFT vertical excitation electronic energies of the valence excited states of anhydrous caffeine are found to be in consonance to the experimental absorption peaks.

  12. Synthesis of anhydrous K2TiOF4 via a mild hydrothermal method

    Science.gov (United States)

    Felder, Justin B.; Yeon, Jeongho; zur Loye, Hans-Conrad

    2015-10-01

    The synthesis of anhydrous K2TiOF4 has been previously attempted by transforming precursor compounds, such as the peroxide (K2Ti(O2)F4), hydrate (K2TiOF4·H2O) and fluoride (K2TiF6). Due to the large structural differences between these precursors and the anhydrous oxyfluorides, however, these preparations have been unsuccessful. Therefore, a direct method of synthesis has been employed to grow single crystals of K2TiOF4 that were characterized by single crystal x-ray diffraction. K2TiOF4 was found to be isostructural with the previously known K2VOF4.

  13. 78 FR 78393 - Standard on the Storage and Handling of Anhydrous Ammonia; Extension of the Office of Management...

    Science.gov (United States)

    2013-12-26

    ...OSHA solicits public comments concerning its proposal to extend OMB approval of the information collection requirements specified in the Storage and Handling of Anhydrous Ammonia Standard (29 CFR 1910.111). Paragraphs (b)(3) and (b)(4) of the Standard have paperwork requirements that apply to non-refrigerated containers and systems and refrigerated containers, respectively; employers use these containers and systems to store and transfer anhydrous ammonia in the workplace.

  14. Conversion of proteins from a non-polarized to an apical secretory pattern in MDCK cells

    International Nuclear Information System (INIS)

    Vogel, Lotte K.; Larsen, Jakob E.; Hansen, Martin; Truffer, Renato

    2005-01-01

    Previously it was shown that fusion proteins containing the amino terminus of an apical targeted member of the serpin family fused to the corresponding carboxyl terminus of the non-polarized secreted serpin, antithrombin, are secreted mainly to the apical side of MDCK cells. The present study shows that this is neither due to the transfer of an apical sorting signal from the apically expressed proteins, since a sequence of random amino acids acts the same, nor is it due to the deletion of a conserved signal for correct targeting from the non-polarized secreted protein. Our results suggest that the polarity of secretion is determined by conformational sensitive sorting signals

  15. Designs of infrared nonpolarizing beam splitters with a Ag layer in a glass cube.

    Science.gov (United States)

    Shi, Jin Hui; Wang, Zheng Ping

    2008-05-10

    A novel design of a nonpolarizing beam splitter with a Ag layer in a cube was proposed and optimized, based on the needle optimization. The digital simulations of the reflectance and reflection-induced retardance were presented. The simulation results showed that both the amplitude and the phase characteristics of the nonpolarizing beam splitter could realize the design targets. The difference between the simulated and the target reflectance of 50% is less than 0.4% and the simulated and the reflection-induced retardance is less than 0.62 degrees in the 1260 -1360 nm range for both p and s components.

  16. Nonpolarizing beam splitter designed by frustrated total internal reflection inside a glass cube.

    Science.gov (United States)

    Xu, Xueke; Shao, Jianda; Fan, Zhengxiu

    2006-06-20

    A method for the design of an all-dielectric nonpolarizing prism beam splitter utilizing the principle of frustrated total internal reflection is reported. The nonpolarizing condition for a prism beam splitter is discussed, and some single layer design examples are elaborated. The concept can be applied to a wide range of wavelengths and arbitrary transmittance values, and with the help of a computer design program examples of 400-700 nm, T(p)=T(s)=0.5+/-0.01, with incident angles of 45 degrees and 62 degrees are given. In addition, the sensitivity and application of the design are also discussed.

  17. Design and analysis of metal-dielectric nonpolarizing beam splitters in a glass cube.

    Science.gov (United States)

    Shi, Jin Hui; Guan, Chun Ying; Wang, Zheng Ping

    2009-06-20

    A novel design of a 25-layer metal-dielectric nonpolarizing beam splitter in a cube is proposed by use of the optimization method and is theoretically investigated. The simulations of the reflectance and differential phases induced by reflection and transmission are presented. The simulation results reveal that both the amplitude and the phase characteristics of the nonpolarizing beam splitter could realize the design targets, the differences between the simulated and the target reflectance of 50% are less than 2%, and the differential phases are less than 3 degrees in the range of 530 nm-570 nm for both p and s components.

  18. Design and analysis of all-dielectric broadband nonpolarizing parallel-plate beam splitters.

    Science.gov (United States)

    Wang, Wenliang; Xiong, Shengming; Zhang, Yundong

    2007-06-01

    Past research on the all-dielectric nonpolarizing beam splitter is reviewed. With the aid of the needle thin-film synthesis method and the conjugate graduate refine method, three different split ratio nonpolarizing parallel-plate beam splitters over a 200 nm spectral range centered at 550 nm with incidence angles of 45 degrees are designed. The chosen materials component and the initial stack are based on the Costich and Thelen theories. The results of design and analysis show that the designs maintain a very low polarization ratio in the working range of the spectrum and has a reasonable angular field.

  19. Optical Interference Coatings Design Contest 2007: triple bandpass filter and nonpolarizing beam splitter.

    Science.gov (United States)

    Tilsch, Markus; Hendrix, Karen

    2008-05-01

    A triple bandpass filter (28 solutions received) and a nonpolarizing beam splitter (23 solutions received) were the subjects of the design contest held in conjunction with the 2007 Optical Interference Coatings topical meeting of the Optical Society of America. Fifteen designers participated using a wide spectrum of design approaches and optimization strategies to create the submissions. The results differ significantly, but all meet the contest requirements. Fabien Lemarchand wins both contests by submitting the thinnest (6254 nm) triple bandpass design and the widest (61.7 nm) nonpolarizing beam-splitter design. Michael Trubetskov is in second place, followed by Vladimir Pervak in both contests. The submitted designs are described and evaluated.

  20. Crystal field influence on vibration spectra: anhydrous uranyl chloride and dihydroxodiuranyl chloride tetrahydrate

    International Nuclear Information System (INIS)

    Perrin, Andre; Caillet, Paul

    1976-01-01

    Vibrational spectra of anhydrous uranyl chloride UO 2 Cl 2 and so called basic uranyl chloride: dihydroxodiuranyl chloride tetrahydrate /UO 2 (OH) 2 UO 2 /Cl 2 (H 2 O) 4 are reported. Factor group method analysis leads for the first time to complete and comprehensive interpretation of their spectra. Two extreme examples of crystal field influence on vibrational spectra are pointed out: for UO 2 Cl 2 , one is unable to explain spectra without taking into account all the elements of primitive crystalline cell, whilst for dihydroxodiuranyl dichloride tetrahydrate the crystal packing has very little effect on vibrational spectra [fr

  1. Using microkinetic analysis to search for novel anhydrous formaldehyde production catalysts

    DEFF Research Database (Denmark)

    Li, Han-Jung; Lausche, Adam C.; Peterson, Andrew A.

    2015-01-01

    Abstract Direct dehydrogenation of methanol to produce anhydrous formaldehyde is investigated using periodic density functional theory (DFT) and combining the microkinetic model to estimate rates and selectivities on stepped (211) surfaces under a desired reaction condition. Binding energies...... that explicitly includes the effects of adsorbate coverage on the rates and selectivities as well as the volcano plots are obtained. Our results show that most of the stepped (211) pure-metallic surfaces such as Au, Pt, Pd, Rh, Ru, Ni, Fe, and Co are located in a region of low activity and selectivity toward CH2O...

  2. Electrolysis of a nitrosyl hexafluoro-molybdate in anhydrous hydrogen fluoride

    International Nuclear Information System (INIS)

    Mougin, Jacques

    1972-01-01

    This thesis addresses the field of irradiated fuel reprocessing, and more particularly the study of the formation of molybdenum hexafluoride (MoF_6) by electrolysis of nitrosyl hexafluoro-molybdate (NOMoF_6) in solution in HF. The author presents the conditions of preparation of an electrolysis in anhydrous HF: solvent purification and control, production of a reference electrode, potential-kinetic study of the behaviour of materials selected for the electrode. The author then addresses the actual hydrolysis of the solution of nitrosyl hexafluoro-molybdate [fr

  3. Relationship between Al content and substitution mechanism of Al-bearing anhydrous bridgmanites

    Science.gov (United States)

    Noda, M.; Inoue, T.; Kakizawa, S.

    2017-12-01

    It is considered that two substitution mechanisms, Tschermak substitution and oxygen vacancy substitution, exist in MgSiO3 bridgmanite for the incorporation of Al in anhydrous condition. Kubo and Akaogi (2000) has conducted the phase equilibrium experiment in the system MgSiO3-Al2O3, and established the phase diagram up to 28 GPa. However the careful observation in the bridgmanite shows that the chemical compositions are slightly deviated from Tschermak substitution join. The same tendency can be also observed in the run products by Irifune et al. (1996). This result indicates that pure Tschermak substitution bridgmanite cannot be stable even in the MgSiO3-Al2O3 join experiment. However, the previous studies used powder samples as the starting materials, so the absorbed water may affect the results. Therefore, we tried to conduct the experiment in the join MgSiO3-Al2O3 in extremely anhydrous condition to clarify whether the pure Tschermak substitution bridgmanite can be stable or not. In addition, we also examined the stability of oxygen vacancy bridgmanite in the extremely anhydrous condition for the comparison. The high pressure synthesis experiments were conducted at 28 GPa and 1600-1700° for 1hour using a Kawai-type multi-anvil apparatus. Four different Al content samples were prepared as the starting materials along the ideal substitution line of Tschermak (Al=0.025, 0.05, 0.1, 0.15 mol) and oxygen-vacancy (Al=0.025, 0.05, 0.075, 0.1 mol) substitutions, respectively (when total cation of 2). The glass rods were used as the starting materials to eliminate the absorbed water on the sample surface. The chemical compositions of the synthesized bridgmanite could not be measured by EPMA because of small grain size less than submicron. Therefore the chemical compositions were estimated from the result of the XRD pattern by subtracting the amount of the other phases. The estimated chemical compositions of Tschermak substitution bridgmanites were consistent with the

  4. Some physical properties of anhydrous and hydrated Brownmillerite doped with NaF

    International Nuclear Information System (INIS)

    Hassaan, M.Y.; El Desoky, M.M.; Salem, S.M.; Yousif, A.A.

    2003-01-01

    Different samples of Brownmillerite (the ferrite phase of cement clinker) doped with 0, 1 or 3 wt.% NaF were prepared. At first, the oxide mixture of Brownmillerite was prepared according to the following composition: 4 mol CaO, 1 mol Al 2 O 3 and 1 mol Fe 2 O 3 in addition to 1 or 3 wt.% NaF. Each mixture was mixed very well, introduced into an electric furnace at 1300 deg. C for 1 h in a platinum crucible, and then quenched in air. The product was divided into four portions mixed with 40 wt.% distilled water to form Brownmillerite paste, except for one portion which was left dry. Each paste was molded into two molds; after 24 h, they were immersed in a distilled water and withdrawn after 1 or 3 days of hydration, respectively. The pastes were ground again. The anhydrous powders of Brownmillerites and the hydrated samples were prepared for a.c. conduction measurements by pressing it to be in pellets form. The two surfaces of each pellet were coated with silver paste. The a.c. conductivity and dielectric constant for different samples were measured using four-probe method. The data was collected from 320 up to 670 K. Moessbauer spectra and X-ray diffraction patterns were measured for each sample (anhydrous and hydrated) to confirm the formation of Brownmillerite, identify the iron states and the magnetic properties. The results showed that NaF addition to Brownmillerite expedites the hydration reaction rate. The superparamagnetic relaxation, which appeared in the anhydrous Brownmillerite spectra due to the small particle size, decreases with increasing the hydration time. Also, the Fe 3+ (Oh) state increases while Fe 3+ (Td) decreases with the time of hydration. The a.c. conductivity value at fixed frequency for anhydrous and hydrated samples was found to increase with NaF addition. The a.c. conductivity and Moessbauer measurements can be used as good tools to verify the purity of Brownmillerite phase and, accordingly, the purity of cement

  5. Polarisation of the spontaneous emission from nonpolar and semipolar InGaN quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Schade, Lukas; Schwarz, Ulrich [Department of Microsystems Engineering, University of Freiburg (IMTEK) (Germany); Fraunhofer Institute for Applied Solid State Physics (IAF) (Germany); Ploch, Simon; Wernicke, Tim [Institute of Solid State Physics, Technical University Berlin (Germany); Knauer, Arne; Hoffmann, Veit; Weyers, Markus [Ferdinand-Braun-Institute (FBH) (Germany); Kneissl, Michael [Institute of Solid State Physics, Technical University Berlin (Germany); Ferdinand-Braun-Institute (FBH) (Germany)

    2011-07-01

    Spontaneously emitted light stemming from semipolar and nonpolar InGaN quantum wells is polarized. This property is a consequence of the broken in-plane symmetry of non c-plane wurtzite quantum wells. We studied the polarized photoluminescence of semipolar and nonpolar InGaN/InGaN multi quantum wells grown on low defect density GaN substrates with a setup for confocal microscopy. For excitation of charge carriers we use a 375 nm diode laser. The photoluminescence is collected with an objective of small NA, to avoid polarisation scrambling, and analyzed with a broadband polarizer and a spectrometer. The experimental results are compared to k.p band structure calculations for semipolar and nonpolar InGaN quantum wells. These simulations provide the polarisation degree of the confined states of the valence band and their energetic splitting. Next, from the thermal occupation the polarized spectra are calculated. The comparison with experimental results allows the determination of the valence subband splitting. Our experiments show a splitting of the two topmost valence subbands in nonpolar direction which is larger than predicted.

  6. Polarization-dependent photoluminescence studies of semipolar and nonpolar InGaN quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Schade, Lukas; Schwarz, Ulrich [IAF, Freiburg (Germany); Wernicke, Tim; Weyers, Markus [FBH, Berlin (Germany); Kneissl, Michael [FBH, Berlin (Germany); Institute of Solid State Physics, TU Berlin (Germany)

    2010-07-01

    Light emitted from optical devices based on semi- and nonpolar GaN quantum well (QW) structures is partially or totally polarized, as a consequence of crystal symmetry and band structure. This can be an additional advantage over polar (0001)GaN in specific applications, e.g. in LED backlighting. Fundamentally, the polarized emission stems from breaking the isotropic symmetry of the hexagonal c-plane, resulting in two discrete semi- and nonpolar directions (parallel and normal to the projection of (0001)). We use the k.p method to simulate the crystal-direction dependent emission. The resulting transition matrix elements assign a specific (partial) polarization for each subband. The thermal occupation of the subbands results in a temperature dependent effective polarization of the light emission. We study MOVPE grown homoepitactical polar, semi- and nonpolar samples, measuring the polarization properties of the resonantly excited photoluminescence from the QW. With the complete polarization of the subbands for nonpolar devices it is possible to measure the energetic difference of the first two valence band levels. In contrast to our calculations we find a higher degree of polarization also in semipolar directions. A possible explanation could be a higher energetic subband difference than computed.

  7. Passive sampling in regulatory chemical monitoring of nonpolar organic compounds in the aquatic environment

    NARCIS (Netherlands)

    Booij, K.; Robinson, C.D.; Burgess, R.M.; Mayer, P.; Roberts, C.A.; Ahrens, L.; Allan, I.J.; Brant, J.; Jones, L.; Kraus, U.R.; Larsen, M.M.; Lepom, P.; Petersen, J.; Pröfrock, D.; Roose, P.; Schäfer, S.; Smedes, F.; Tixier, C.; Vorkamp, K.; Whitehouse, P.

    2016-01-01

    We reviewed compliance monitoring requirements in the EuropeanUnion, the United States, and the Oslo-Paris Convention for the protection of themarine environment of the North-East Atlantic, and evaluated if these are met bypassive sampling methods for nonpolar compounds. The strengths

  8. Role of the electronegativity for the interface properties of non-polar heterostructures

    KAUST Repository

    Nazir, Safdar; Singh, Nirpendra; Kahaly, M. Upadhyay; Schwingenschlö gl, Udo

    2012-01-01

    Density functional theory is used to investigate the interfaces in the non-polar ATiO 3/SrTiO 3 (A=Pb, Ca, Ba) heterostructures. All TiO 2-terminated interfaces show an insulating behavior. By reduction of the O content in the AO, SrO, and TiO 2

  9. Temperature programmed retention indices : calculation from isothermal data Part 2: Results with nonpolar columns

    NARCIS (Netherlands)

    Curvers, J.M.P.M.; Rijks, J.A.; Cramers, C.A.M.G.; Knauss, K.; Larson, P.

    1985-01-01

    The procedure for calculating linear temperature programmed indices as described in part 1 has been evaluated using five different nonpolar columns, with OV-1 as the stationary phase. For fourty-three different solutes covering five different classes of components, including n-alkanes and

  10. The influence of non-polar lipids on tear film dynamics

    KAUST Repository

    Bruna, M.; Breward, C.  J.  W.

    2014-01-01

    © 2014 Cambridge University Press. In this paper we examine the effect that physiological non-polar lipids, residing on the surface of an aqueous tear film, have on the film evolution. In our model we track the evolution of the thickness of the non

  11. An Efficient, Solvent-Free Process for Synthesizing Anhydrous MgCl2

    Energy Technology Data Exchange (ETDEWEB)

    Motkuri, Radha K.; Vemuri, Venkata Rama S.; Barpaga, Dushyant; Schaef, Herbert T.; Loring, John S.; Martin, Paul F.; Lao, David; Nune, Satish K.; McGrail, Bernard P.

    2018-01-02

    A new efficient and solvent-free method for the synthesis of anhydrous MgCl2 from its hexahydrate is proposed. Fluidized dehydration of MgCl2·6H2O feedstock at 200 °C in a porous bed reactor yields MgCl2·nH2O (0 < n < 1), which has a similar diffraction pattern as activated MgCl2. The MgCl2·nH2O is then ammoniated directly using liquefied NH3 in the absence of solvent to form MgCl2·6NH3. Calcination of the hexammoniate complex at 300 °C then yields anhydrous MgCl2. Both dehydration and deammoniation were thoroughly studied using in situ as well as ex situ characterization techniques. Specifically, a detailed understanding of the dehydration process was monitored by in situ PXRD and in situ FTIR techniques where formation of salt with nH2O (n = 4, 2, 1, <1) was characterized. Given the reduction in thermal energy required to produce dehydrated feedstock with this method compared with current strategies, significant cost benefits are expected. Overall, the combined effect of activation, macroporosity, and coordinated water depletion allows the formation of hexammoniate without using solvent, thus minimizing waste formation.

  12. Study of gasoline mixture with 10% of anhydrous ethanol. Physic-chemical properties evaluation

    International Nuclear Information System (INIS)

    Torres, Jaime; Molina, Daniel; Pinto, Carlos; Rueda, Fernando

    2002-01-01

    This study includes the assessment results for blends of premium and regular gasoline produced in Barrancabermeja' s refinery with 10vol% anhydrous ethanol and concentrations within this range (from 5vol% to 15vol%). The results may allow for a more precise definition of the characteristics for the desired blend. The survey basically focused on the Reid vapor pressure (RVP) and the antiknock index (RON+MON/2) properties, in order to determine the variations within these properties when 5vol%, 10vol%, and 15vol% anhydrous ethanol is added to the base fuels. Based on these results, the RVP and antiknock index were determined for the base fuels, blended with 10vol% ethanol, to comply with the quality standards required for Colombian fuels in year 2005. For the adjustment of the base fuel's RVP, light-vapors, nitrogen-dragging stripper was designed and built. As for the adjustment of the base fuel's antiknock index, blends with straight naphtha were made for lower index values, while blends with cracked naphtha and high octane alkylate were made for higher index values. Having determined the specifications for base fuels, as required to blend them with 10vol% ethanol and meet the quality standards for Colombian gasoline in year 2005, water tolerance for the blends was estimated at temperature ranges of 273 k to 313 k

  13. A new anhydrous proton conductor based on polybenzimidazole and tridecyl phosphate

    International Nuclear Information System (INIS)

    Jiang Fengjing; Pu Hongting; Meyer, Wolfgang H.; Guan Yisi; Wan Decheng

    2008-01-01

    Most of the anhydrous proton conducting membranes are based on inorganic or partially inorganic materials, like SrCeO 3 membranes or polybenzimidazole (PBI)/H 3 PO 4 composite membranes. In present work, a new kind of anhydrous proton conducting membrane based on fully organic components of PBI and tridecyl phosphate (TP) was prepared. The interaction between PBI and TP is discussed. The temperature dependence of the proton conductivity of the composite membranes can be modeled by an Arrhenius relation. Thermogravimetric analysis (TGA) illustrates that these composite membranes are chemically stable up to 145 deg. C. The weight loss appearing at 145 deg. C is attributed to the selfcondensation of phosphate, which results in the proton conductivity drop of the membranes occurring at the same temperature. The DC conductivity of the composite membranes can reach ∼10 -4 S/cm for PBI/1.8TP at 140 deg. C and increases with increasing TP content. The proton conductivity of PBI/TP and PBI/H 3 PO 4 composite membranes is compared. The former have higher proton conductivity, however, the proton conductivity of the PBI/H 3 PO 4 membranes increases with temperature more significantly. Compared with PBI/H 3 PO 4 membranes, the migration stability of TP in PBI/TP membranes is improved significantly

  14. Surface chemistry and electronic structure of nonpolar and polar GaN films

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Monu; Krishna, T.C. Shibin; Aggarwal, Neha; Gupta, Govind, E-mail: govind@nplindia.org

    2015-08-01

    Highlights: • Surface chemistry and electronic structure of polar and nonpolar GaN is reported. • Influence of polarization on electron affinity of p & np GaN films is investigated. • Correlation between surface morphology and polarity has been deduced. - Abstract: Photoemission and microscopic analysis of nonpolar (a-GaN/r-Sapphire) and polar (c-GaN/c-Sapphire) epitaxial gallium nitride (GaN) films grown via RF-Molecular Beam Epitaxy is reported. The effect of polarization on surface properties like surface states, electronic structure, chemical bonding and morphology has been investigated and correlated. It was observed that polarization lead to shifts in core level (CL) as well as valence band (VB) spectra. Angle dependent X-ray Photoelectron Spectroscopic analysis revealed higher surface oxide in polar GaN film compared to nonpolar GaN film. On varying the take off angle (TOA) from 0° to 60°, the Ga−O/Ga−N ratio varied from 0.11–0.23 for nonpolar and 0.17–0.36 for polar GaN film. The nonpolar film exhibited N-face polarity while Ga-face polarity was perceived in polar GaN film due to the inherent polarization effect. Polarization charge compensated surface states were observed on the polar GaN film and resulted in downward band bending. Ultraviolet photoelectron spectroscopic measurements revealed electron affinity and ionization energy of 3.4 ± 0.1 eV and 6.8 ± 0.1 eV for nonpolar GaN film and 3.8 ± 0.1 eV and 7.2 ± 0.1 eV for polar GaN film respectively. Field Emission Scanning Electron Microscopy measurements divulged smooth morphology with pits on polar GaN film. The nonpolar film on the other hand showed pyramidal structures having facets all over the surface.

  15. Anhydrous proton exchange membrane of sulfonated poly(ether ether ketone) enabled by polydopamine-modified silica nanoparticles

    International Nuclear Information System (INIS)

    Wang, Jingtao; Bai, Huijuan; Zhang, Haoqin; Zhao, Liping; Chen, Huiling; Li, Yifan

    2015-01-01

    Highlights: • The concept of acid/base pairs was employed to design anhydrous PEMs. • Polydopamine-modified silica particles were uniformly dispersed in SPEEK membrane. • The membranes displayed enhancement in both stability and anhydrous proton conductivity. - Abstract: Novel anhydrous proton exchange membrane is (PEM) facilely prepared by embedding dopamine-modified silica nanoparticles (DSiOis 2 ) into sulfonated poly (ether ether ketone) (SPEEK) polymer matrix. DSiO 2 bearing -NH 2 /-NH- groups are synthesized inspired by the bioadhesion principle, which are uniformly dispersed within SPEEK membrane due to the good interfacial compatibility. The interfacial electrostatic attractions render unique rearrangement of the nanophase-separated structure and the chain packing of the resultant hybrid membranes. As a result, the thermal and mechanical stabilities as well as structural stability of the hybrid membranes are enhanced when compared to SPEEK control membrane. On the other hand, induced by the attractions, acid–base pairs are formed at the SPEEK/DSiOarewere 2 interface, where fast proton transfer via Grotthuss mechanism is expected. These features confer much higher proton conductivities on the DSiO 2 -filled membranes under both hydrated and anhydrous conditions, compared to those of the SPEEK control membrane and SiO 2 -filled membranes. Particularly, the hybrid membrane with 15 wt% DSiO 2 achieve the highest conductivities of 4.52achieveachieved × 10 −3 S cm −1 at 120 °C under anhydrous condition, which is much higher than the SPEEK control membrane and the commercial Nafion membrane (0.1iswas × 10 −3 S cm −1 ). The membrane with 9 wt% DSiO 2 show an open cell potential of 0.98showshowed V and an optimum power density of 111.7 mW cm −2 , indicative of its potential application in fuel cell under anhydrous condition

  16. Polarographic study of Cd(2), Pb(2), Hg(1) in anhydrous acetic acid; Etude polarographique de Cd(2), Pb(2), Hg(1) dans l'acide acetique anhydre

    Energy Technology Data Exchange (ETDEWEB)

    Conesa-Botta, M C [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1966-07-01

    Anhydrous acetic acid is a solvent which can be compared to water as far as its behaviour towards acid-base reactions is concerned. It is in fact, like water both a proton acceptor (basic) - and as such it can provoke the dissociation of acids - and a proton donor (acid). This amphoteric behaviour is characterized by the equilibrium: 2 H O Ac {r_reversible} Ac OH{sub 2}{sup +} + Ac O{sup -} with K{sub i} = |Ac O H{sub 2}|{sup +} |Ac O{sup -}| = 10{sup -14.5} analogue to 2 H{sub 2}O {r_reversible} H{sub 3}O{sup +} + HO{sup -} with K{sub i} = |H{sub 3}O{sup +}| |HO{sup -}| = 10{sup -14} The acid-base reactions can in principle be characterized by a pH scale based on a definition similar to that for the pH scale in aqueous solutions. The essential difference however between aqueous and acetic acid solutions is due to the fact that acetic acid has a low dielectric constant. {epsilon} = 6.1 (at 25 deg. C) The ions therefore remain associated, almost completely, in the form of ion-pairs produced as a result of the strong electrostatic interactions. This phenomenon requires us to modify the reasoning usually applied to aqueous solutions. The new general methods of reasoning have been established and discussed by G. CHARLOT and B. TREMILLON. We will make use of them for the particular case under consideration. In the first part, we have employed the polarographic method for the study of the acetic complexes of two elements: cadmium(II) and lead (II). In the second part we have tried to show that mercurous halides are formed in acetic acid; we have attempted to determine their stability. (author) [French] L'acide acetique anhydre est un solvant qui peut etre rapproche de l'eau par son comportement envers les reactions acides-bases. Il est en effet, comme l'eau, a la fois accepteur de protons (basique) - et comme tel agit sur la dissociation des acides - et donneur de protons (acide). Ce pouvoir amphotere est caracterise par l'equilibre: 2 H O Ac {r_reversible} Ac OH{sub 2

  17. Mechanical properties of lunar materials under anhydrous, hard vacuum conditions: applications of lunar glass structural components

    International Nuclear Information System (INIS)

    Blacic, J.D.

    1984-01-01

    Lunar materials and derivatives such as glass may possess very high tensile strengths compared to equivalent materials on earth because of the absence of hydrolytic weakening processes on the moon and in the hard vacuum of free space. Hydrolyzation of Si-O bonds at crack tips or dislocations reduces the strength of silicates by about an order of magnitude in earth environments. However, lunar materials are extremely anhydrous and hydrolytic weakening will be suppressed in free space. Thus, the geomechanical properties of the moon and engineering properties of lunar silicate materials in space environments will be very different than equivalent materials under earth conditions where the action of water cannot be conveniently avoided. Possible substitution of lunar glass for structural metals in a variety of space engineering applications enhances the economic utilization of the moon. 26 references, 3 figures, 2 tables

  18. Controlled synthesis of porous anhydrous cobalt oxalate nanorods with high reversible capacity and excellent cycling stability

    International Nuclear Information System (INIS)

    Xu, Junmin; He, Lei; Liu, Hui; Han, Tao; Wang, Yongjian; Zhang, Changjin; Zhang, Yuheng

    2015-01-01

    Graphical abstract: Display Omitted -- Abstract: One-dimensional porous anhydrous cobalt oxalate nanorods are prepared via a facile water-controlled coprecipitate method followed by thermal annealing treatment under N 2 at 300 °C. The nanorods are characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. When evaluated as an anode material for lithium ion batteries, the nanorods exhibit high reversible specific capacity and excellent cycling stability (924 mA h g −1 at 50 mA g −1 after 100 cycles and 709 mA h g −1 at 200 mA g −1 after 220 cycles). This remarkable electrochemical performance is attributed to the one-dimensional porous nanostructure that can provide large electrode/electrolyte contact area and short lithium-ion diffusion pathway, meanwhile reduce the volume expansion during the repeated discharge/charge process

  19. Detailed kinetic and heat transport model for the hydrolysis of lignocellulose by anhydrous hydrogen fluoride vapor

    Energy Technology Data Exchange (ETDEWEB)

    Rorrer, G.L.; Mohring, W.R.; Lamport, D.T.A.; Hawley, M.C.

    1988-01-01

    Anhydrous Hydrogen Fluoride (HF) vapor at ambient conditions efficiently and rapidly hydrolyzed lignocellulose to glucose and lignin. The unsteady-state reaction of HF vapor with a single lignocellulose chip was mathematically modeled under conditions where external and internal mass-transfer resistances were minimized. The model incorporated physical adsorption of HF vapor onto the lignocellulosic matrix and solvolysis of cellulose to glucosyl fluoride by adsorbed HF into the differential material and energy balance expressions. Model predictions for the temperature distribution and global glucose yield in the HF-reacting lignocellulose chip as a function of reaction time and HF vapor stream temperature agreed reasonably with the complimentary experimental data. The model correctly predicted that even when mass-transfer resistances for the reaction of HF vapor with a single lignocellulose chip are minimized, external and internal heat-transfer resistances are still significant.

  20. SIMULATION OF THE DISTILLATION BY PRESSURE REDUCTION TO OBTAIN ANHYDROUS ETHANOL

    Directory of Open Access Journals (Sweden)

    Yeney Lauzurique Guerra

    2016-10-01

    Full Text Available In this work the distillation by pressure reduction was evaluated through the HYSYS v3.2 process simulator. Due to the lack of data in the consulted bibliography to perform the simulation, the STATGRAPHICS Centurion XVI software was used to obtain a response surface that would define optimal operating conditions. The property package selected to work was based on the Margules model. An anhydrous ethanol molar composition of 0.9917 was obtained. Temperature profiles were analyzed as well as liquid and vapor molar flows and dehydration column composition profiles. The influence of operating parameters on the efficiency of simulated technology was determined by analyzing one case study. According to economic evaluation, the implementation of this technology is not economically profitable; taking into account current prices and costs mostly due to high energy consumption and construction costs of the tower. This result contributes to the pursuit of other profitable technologies from the economic point of view.

  1. Structural study and crystallography of the major compound of anhydrous cement: tri-calcium silicate; Etude structurale et cristallographie du compose majoritaire du ciment anhydre: le silicate tricalcique

    Energy Technology Data Exchange (ETDEWEB)

    Noirfontaine, M.N. de

    2000-01-01

    Anhydrous (Portland) cement is mainly composed of a synthetic material, the clinker, whose major compound is tri-calcium silicate (Ca{sub 3}SiO{sub 5}), often referred as C{sub 3}S with the compact oxides notations, C = CaO et S = SiO{sub 2}. The polymorphism of C{sub 3}S, still not well known, is the main subject of the thesis. Various crystal structures (rhombohedral R, monoclinic M1, M2, M3 and triclinic T1, T2, T3) can be found, depending on temperature and impurities. The only known structures are T1, M1 and M3, involving large unit cells with an orientational disorder of silicate tetrahedra. The single crystal studies exhibit no clear relation between the various polymorphs. Starting from known results from literature single crystal experiments, we establish the metric and structural relations between the different structures. Averaged structures for the T1, M1 and M3 polymorphs are proposed, together with all the matrices of transformation between the unit cells. We also introduce new 1-D, 2-D, and 3-D structural units, which make easier the understanding of the structures of C{sub 3}S, with the result of a better description of the orientational disorder. The effects of impurities on the structure are discussed. In industrial clinkers, impurities stabilize mainly M1 and M3 monoclinic forms. We propose a space group (Pc) and two structural models (a superstructure and an approximate averaged structure) for the M1 form. All the models are validated on synthetic compounds (M3, M2, M1 et T1) and industrial clinkers analysed by X-Ray powder diffraction with Rietveld analysis. (author)

  2. Structural basis for the transformation pathways of the sodium naproxen anhydrate-hydrate system.

    Science.gov (United States)

    Bond, Andrew D; Cornett, Claus; Larsen, Flemming H; Qu, Haiyan; Raijada, Dhara; Rantanen, Jukka

    2014-09-01

    Crystal structures are presented for two dihydrate polymorphs (DH-I and DH-II) of the non-steroidal anti-inflammatory drug sodium (S)-naproxen. The structure of DH-I is determined from twinned single crystals obtained by solution crystallization. DH-II is obtained by solid-state routes, and its structure is derived using powder X-ray diffraction, solid-state (13)C and (23)Na MAS NMR, and molecular modelling. The validity of both structures is supported by dispersion-corrected density functional theory (DFT-D) calculations. The structures of DH-I and DH-II, and in particular their relationships to the monohydrate (MH) and anhydrate (AH) structures, provide a basis to rationalize the observed transformation pathways in the sodium (S)-naproxen anhydrate-hydrate system. All structures contain Na(+)/carboxylate/H2O sections, alternating with sections containing the naproxen molecules. The structure of DH-I is essentially identical to MH in the naproxen region, containing face-to-face arrangements of the naphthalene rings, whereas the structure of DH-II is comparable to AH in the naproxen region, containing edge-to-face arrangements of the naphthalene rings. This structural similarity permits topotactic transformation between AH and DH-II, and between MH and DH-I, but requires re-organization of the naproxen molecules for transformation between any other pair of structures. The topotactic pathways dominate at room temperature or below, while the non-topotactic pathways become active at higher temperatures. Thermochemical data for the dehydration processes are rationalized in the light of this new structural information.

  3. Composite polymer electrolyte containing ionic liquid and functionalized polyhedral oligomeric silsesquioxanes for anhydrous PEM applications.

    Science.gov (United States)

    Subianto, Surya; Mistry, Mayur K; Choudhury, Namita Roy; Dutta, Naba K; Knott, Robert

    2009-06-01

    A new type of supported liquid membrane was made by combining an ionic liquid (IL) with a Nafion membrane reinforced with multifunctional polyhedral oligomeric silsesquioxanes (POSSs) using a layer-by-layer strategy for anhydrous proton-exchange membrane (PEM) application. The POSS was functionalized by direct sulfonation, and the sulfonated POSS (S-POSS) was incorporated into Nafion 117 membranes by the infiltration method. The resultant hybrid membrane shows strong ionic interaction between the Nafion matrix and the multifunctional POSS, resulting in increased glass transition temperature and thermal stability at very low loadings of S-POSS (1%). The presence of S-POSS has also improved the proton conductivity especially at low humidities, where it shows a marked increase due to its confinement in the ionic domains and promotes water uptake by capillary condensation. In order to achieve anhydrous conductivity, the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI) was incorporated into these membranes to provide proton conduction in the absence of water. Although the incorporation of an IL shows a plasticizing effect on the Nafion membrane, the S-POSS composite membrane with an IL shows a higher modulus at high temperatures compared to Nafion 117 and a Nafion-IL membrane, with significantly higher proton conductivity (5 mS/cm at 150 degrees C with 20% IL). This shows the ability of the multifunctional POSS and IL to work symbiotically to achieve the desirable proton conductivity and mechanical properties of such membranes by enhancing the ionic interaction within the material.

  4. Effects of coffee and caffeine anhydrous on strength and sprint performance.

    Science.gov (United States)

    Trexler, Eric T; Smith-Ryan, Abbie E; Roelofs, Erica J; Hirsch, Katie R; Mock, Meredith G

    2016-09-01

    Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, 10-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300 mg flat dose; yielding 3-5 mg/kg bodyweight), COF (8.9 g; 303 mg caffeine), or placebo (PLA; 3.8 g non-caloric flavouring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p = .04), but not PLA (p = .99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p > .05). There were no sprint × treatment interactions for PP or TW (p > .05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise.

  5. Crystal structure of aspartame anhydrate from powder diffraction data. Structural aspects of the dehydration process of aspartame

    NARCIS (Netherlands)

    Guguta, C.; Meekes, H.L.M.; Gelder, R. de

    2006-01-01

    Aspartame has three pseudo-polymorphic forms, two hydrates and a hemi-hydrate, for which crystal structures were determined from single-crystal diffraction data. This paper presents the crystal structure of the anhydrate, which was obtained by dehydrating the hemi-hydrate. The crystal structure of

  6. 75 FR 13441 - Hours of Service; Limited 90-Day Waiver for the Distribution of Anhydrous Ammonia in Agricultural...

    Science.gov (United States)

    2010-03-22

    ..., such as grain hauled from an elevator (or sugar beets from a cold storage facility) to a processing... delivering anhydrous ammonia; (2) none of the transportation movements within the distribution chain exceed a... chain exceed a 100 air-mile radius--whether from the retail or wholesale distribution point; and (3) the...

  7. Improved quantification of alite and belite in anhydrous Portland cements by 29Si MAS NMR: Effects of paramagnetic ions

    DEFF Research Database (Denmark)

    Poulsen, Søren Lundsted; Kocaba, Vanessa; Le Saoût, Gwenn

    2009-01-01

    The applicability, reliability, and repeatability of 29Si MAS NMR for determination of the quantities of alite (Ca3SiO5) and belite (Ca2SiO4) in anhydrous Portland cement was investigated in detail for 11 commercial Portland cements and the results compared with phase quantifications based...

  8. Anhydrous ZnCl2: A Highly Efficient Reagent for Facile and Regioselective Conversion of Epoxides to β-Chlorohydrins

    Directory of Open Access Journals (Sweden)

    Ronak Eisavi

    2016-01-01

    Full Text Available Facile conversion of structurally different epoxides to the corresponding β-chlorohydrins was carried out successfully with anhydrous ZnCl2 in CH3CN. The reactions were carried out within 10-50 min to give β-chlorohydrins with perfect regioselectivity and high yields (80-97%.

  9. Passive Sampling in Regulatory Chemical Monitoring of Nonpolar Organic Compounds in the Aquatic Environment

    DEFF Research Database (Denmark)

    Booij, Kees; Robinson, Craig D; Burgess, Robert M

    2016-01-01

    We reviewed compliance monitoring requirements in the European Union, the United States, and the Oslo-Paris Convention for the protection of the marine environment of the North-East Atlantic, and evaluated if these are met by passive sampling methods for nonpolar compounds. The strengths...... is the best available technology for chemical monitoring of nonpolar organic compounds. Key issues to be addressed by scientists and environmental managers are outlined....... and shortcomings of passive sampling are assessed for water, sediments, and biota. Passive water sampling is a suitable technique for measuring concentrations of freely dissolved compounds. This method yields results that are incompatible with the EU's quality standard definition in terms of total concentrations...

  10. Broadband non-polarizing terahertz beam splitters with variable split ratio

    KAUST Repository

    Wei, Minggui

    2017-08-15

    Seeking effective terahertz functional devices has always aroused extensive attention. Of particular interest is the terahertz beam splitter. Here, we have proposed, designed, manufactured, and tested a broadband non-polarizing terahertz beam splitter with a variable split ratio based on an all-dielectric metasurface. The metasurface was created by patterning a dielectric surface of the N-step phase gradient and etching to a few hundred micrometers. The conversion efficiency as high as 81% under the normal incidence at 0.7 THz was achieved. Meanwhile, such a splitter works well over a broad frequency range. The split ratio of the proposed design can be continuously tuned by simply shifting the metasurface, and the angle of emergences can also be easily adjusted by choosing the step of phase gradients. The proposed design is non-polarizing, and its performance is kept under different polarizations.

  11. Broadband non-polarizing terahertz beam splitters with variable split ratio

    Science.gov (United States)

    Wei, Minggui; Xu, Quan; Wang, Qiu; Zhang, Xueqian; Li, Yanfeng; Gu, Jianqiang; Tian, Zhen; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili

    2017-08-01

    Seeking effective terahertz functional devices has always aroused extensive attention. Of particular interest is the terahertz beam splitter. Here, we have proposed, designed, manufactured, and tested a broadband non-polarizing terahertz beam splitter with a variable split ratio based on an all-dielectric metasurface. The metasurface was created by patterning a dielectric surface of the N-step phase gradient and etching to a few hundred micrometers. The conversion efficiency as high as 81% under the normal incidence at 0.7 THz was achieved. Meanwhile, such a splitter works well over a broad frequency range. The split ratio of the proposed design can be continuously tuned by simply shifting the metasurface, and the angle of emergences can also be easily adjusted by choosing the step of phase gradients. The proposed design is non-polarizing, and its performance is kept under different polarizations.

  12. Multi-wavelength metal-dielectric nonpolarizing beam splitters in the near-infrared range

    Science.gov (United States)

    Hui Shi, Jin; Ping Wang, Zheng; Ying Guan, Chun; Yang, Jun; Shu Fu, Tian

    2011-04-01

    A 21-layer multi-wavelength metal-dielectric nonpolarizing cube beam splitter was designed by use of an optimization method and theoretically investigated in the near-infrared range. The angular dependence of the reflectance and differential phases induced by reflection and transmission were presented. The simulation results revealed that the non-polarizing effect could be achieved for both the amplitude and phase characteristics at 1310 and 1550 nm. The differences between the simulated and the target reflectance of 50% are less than 2% and differential phases are less than 5°in the range 1300-1320 nm and 1540-1550 nm for both p- and s-components.

  13. Broadband non-polarizing terahertz beam splitters with variable split ratio

    KAUST Repository

    Wei, Minggui; Xu, Quan; Wang, Qiu; Zhang, Xueqian; Li, Yanfeng; Gu, Jianqiang; Tian, Zhen; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili

    2017-01-01

    Seeking effective terahertz functional devices has always aroused extensive attention. Of particular interest is the terahertz beam splitter. Here, we have proposed, designed, manufactured, and tested a broadband non-polarizing terahertz beam splitter with a variable split ratio based on an all-dielectric metasurface. The metasurface was created by patterning a dielectric surface of the N-step phase gradient and etching to a few hundred micrometers. The conversion efficiency as high as 81% under the normal incidence at 0.7 THz was achieved. Meanwhile, such a splitter works well over a broad frequency range. The split ratio of the proposed design can be continuously tuned by simply shifting the metasurface, and the angle of emergences can also be easily adjusted by choosing the step of phase gradients. The proposed design is non-polarizing, and its performance is kept under different polarizations.

  14. Observations of Rabi oscillations in a non-polar InGaN quantum dot

    International Nuclear Information System (INIS)

    Reid, Benjamin P. L.; Chan, Christopher C. S.; Taylor, Robert A.; Kocher, Claudius; Zhu, Tongtong; Oehler, Fabrice; Emery, Robert; Oliver, Rachel A.

    2014-01-01

    Experimental observation of Rabi rotations between an exciton excited state and the crystal ground state in a single non-polar InGaN quantum dot is presented. The exciton excited state energy is determined by photoluminescence excitation spectroscopy using two-photon excitation from a pulsed laser. The population of the exciton excited state is seen to undergo power dependent damped Rabi oscillations.

  15. Observations of Rabi oscillations in a non-polar InGaN quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Benjamin P. L., E-mail: benjamin.reid@physics.ox.ac.uk; Chan, Christopher C. S.; Taylor, Robert A. [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Kocher, Claudius [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Konstanz University, Konstanz (Germany); Zhu, Tongtong; Oehler, Fabrice; Emery, Robert; Oliver, Rachel A. [Department of Materials Science and Metallurgy, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

    2014-06-30

    Experimental observation of Rabi rotations between an exciton excited state and the crystal ground state in a single non-polar InGaN quantum dot is presented. The exciton excited state energy is determined by photoluminescence excitation spectroscopy using two-photon excitation from a pulsed laser. The population of the exciton excited state is seen to undergo power dependent damped Rabi oscillations.

  16. Critical thickness for the formation of misfit dislocations originating from prismatic slip in semipolar and nonpolar III-nitride heterostructures

    KAUST Repository

    Smirnov, A. M.; Young, E. C.; Bougrov, V. E.; Speck, J. S.; Romanov, A. E.

    2016-01-01

    We calculate the critical thickness for misfit dislocation (MD) formation in lattice mismatched semipolar and nonpolar III-nitride wurtzite semiconductor layers for the case of MDs originated from prismatic slip (PSMDs). It has been shown

  17. NMR-Based Identification of Metabolites in Polar and Non-Polar Extracts of Avian Liver.

    Science.gov (United States)

    Fathi, Fariba; Brun, Antonio; Rott, Katherine H; Falco Cobra, Paulo; Tonelli, Marco; Eghbalnia, Hamid R; Caviedes-Vidal, Enrique; Karasov, William H; Markley, John L

    2017-11-16

    Metabolites present in liver provide important clues regarding the physiological state of an organism. The aim of this work was to evaluate a protocol for high-throughput NMR-based analysis of polar and non-polar metabolites from a small quantity of liver tissue. We extracted the tissue with a methanol/chloroform/water mixture and isolated the polar metabolites from the methanol/water layer and the non-polar metabolites from the chloroform layer. Following drying, we re-solubilized the fractions for analysis with a 600 MHz NMR spectrometer equipped with a 1.7 mm cryogenic probe. In order to evaluate the feasibility of this protocol for metabolomics studies, we analyzed the metabolic profile of livers from house sparrow ( Passer domesticus ) nestlings raised on two different diets: livers from 10 nestlings raised on a high protein diet (HP) for 4 d and livers from 12 nestlings raised on the HP diet for 3 d and then switched to a high carbohydrate diet (HC) for 1 d. The protocol enabled the detection of 52 polar and nine non-polar metabolites in ¹H NMR spectra of the extracts. We analyzed the lipophilic metabolites by one-way ANOVA to assess statistically significant concentration differences between the two groups. The results of our studies demonstrate that the protocol described here can be exploited for high-throughput screening of small quantities of liver tissue (approx. 100 mg wet mass) obtainable from small animals.

  18. Charge transport in non-polar and semi-polar III-V nitride heterostructures

    International Nuclear Information System (INIS)

    Konar, Aniruddha; Verma, Amit; Fang, Tian; Zhao, Pei; Jana, Raj; Jena, Debdeep

    2012-01-01

    Compared to the intense research focus on the optical properties, the transport properties in non-polar and semi-polar III-nitride semiconductors remain relatively unexplored to date. The purpose of this paper is to discuss charge-transport properties in non-polar and semi-polar orientations of GaN in a comparative fashion to what is known for transport in polar orientations. A comprehensive approach is adopted, starting from an investigation of the differences in the electronic bandstructure along different polar orientations of GaN. The polarization fields along various orientations are then discussed, followed by the low-field electron and hole mobilities. A number of scattering mechanisms that are specific to non-polar and semi-polar GaN heterostructures are identified, and their effects are evaluated. Many of these scattering mechanisms originate due to the coupling of polarization with disorder and defects in various incarnations depending on the crystal orientation. The effect of polarization orientation on carrier injection into quantum-well light-emitting diodes is discussed. This paper ends with a discussion of orientation-dependent high-field charge-transport properties including velocity saturation, instabilities and tunneling transport. Possible open problems and opportunities are also discussed. (paper)

  19. Design of reproducible polarized and non-polarized edge filters using genetic algorithm

    International Nuclear Information System (INIS)

    Ejigu, Efrem Kebede; Lacquet, B M

    2010-01-01

    Recent advancement in optical fibre communications technology is partly due to the advancement of optical thin film technology. The advancement of optical thin film technology includes the development of new and existing optical filter design methods. The genetic algorithm is one of the new design methods that show promising results in designing a number of complicated design specifications. It is the finding of this study that the genetic algorithm design method, through its optimization capability, can give more reliable and reproducible designs of any specifications. The design method in this study optimizes the thickness of each layer to get to the best possible solution. Its capability and unavoidable limitations in designing polarized and non-polarized edge filters from absorptive and dispersive materials is well demonstrated. It is also demonstrated that polarized and non-polarized designs from the genetic algorithm are reproducible with great success. This research has accomplished the great task of formulating a computer program using the genetic algorithm in a Matlab environment for the design of a reproducible polarized and non-polarized filters of any sort from any kind of materials

  20. Electric Charge Accumulation in Polar and Non-Polar Polymers under Electron Beam Irradiation

    Science.gov (United States)

    Nagasawa, Kenichiro; Honjoh, Masato; Takada, Tatsuo; Miyake, Hiroaki; Tanaka, Yasuhiro

    The electric charge accumulation under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method in the dielectric insulation materials, such as polar polymeric films (polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI), and polyethylene-terephthalate (PET)) and non-polar polymeric films (polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetrafluoroethylene (PTFE)). The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation over 50 C/m3 and long saturation time over 80 minutes. The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m3 and middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) showed the properties of small amount of charge accumulation about 5 to 20 C/m3 and within short saturation time about 1.0 minutes. This paper summarizes the relationship between the properties of charge accumulation and chemical structural formula, and compares between the electro static potential distribution with negative charged polymer and its chemical structural formula.

  1. Electric charge accumulation in polar and non-polar polymers under electron beam irradiation

    International Nuclear Information System (INIS)

    Nagasawa, Kenichiro; Honjoh, Masato; Takada, Tatsuo; Miyake, Hiroaki; Tanaka, Yasuhiro

    2010-01-01

    The electric charge accumulation under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method in the dielectric insulation materials, such as polar polymeric films (polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI), and polyethylene-terephthalate (PET)) and non-polar polymeric films (polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetrafluoroethylene (PTFE)). The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation over 50 C/m 3 and long saturation time over 80 minutes. The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m 3 and middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) showed the properties of small amount of charge accumulation about 5 to 20 C/m 3 and within short saturation time about 1.0 minutes. This paper summarizes the relationship between the properties of charge accumulation and chemical structural formula, and compares between the electro static potential distribution with negative charged polymer and its chemical structural formula. (author)

  2. The Role of Hydrogen Bonding on Laminar Burning Velocity of Hydrous and Anhydrous Ethanol Fuel with Small Addition of n-Heptane

    Directory of Open Access Journals (Sweden)

    I Made Suarta

    2016-01-01

    Full Text Available The molecular structure of mixed hydrous and anhydrous ethanol with up to 10% v n-heptane had been studied. The burning velocity was examined in a cylindrical explosion combustion chamber. The result showed that the burning velocity of hydrous ethanol is higher than anhydrous ethanol and n-heptane at stoichiometric, rich, and very rich mixtures. The burning velocity of hydrous ethanol with n-heptane drops drastically compared to the burning velocity of anhydrous ethanol with n-heptane. It is caused by two reasons. Firstly, there was a composition change of azeotropic hydrous ethanol molecules within the mixture of fuel. Secondly, at the same volume the number of ethanol molecules in hydrous ethanol was less than in anhydrous ethanol at the same composition of the n-heptane in the mixture. At the mixture of anhydrous ethanol with n-heptane, the burning velocity decreases proportionally to the addition of the n-heptane composition. The burning velocity is between the velocities of anhydrous ethanol and n-heptane. It shows that the burning velocity of anhydrous ethanol mixed with n-heptane is only influenced by the mixture composition.

  3. An absorbing microwave micro-solid-phase extraction device used in non-polar solvent microwave-assisted extraction for the determination of organophosphorus pesticides

    International Nuclear Information System (INIS)

    Wang Ziming; Zhao Xin; Xu Xu; Wu Lijie; Su Rui; Zhao Yajing; Jiang Chengfei; Zhang Hanqi; Ma Qiang; Lu Chunmei; Dong Deming

    2013-01-01

    Highlights: ► An absorbing microwave μ-SPE device packed with activated carbon was used. ► Absorbing microwave μ-SPE device was made and used to enrich the analytes. ► Absorbing microwave μ-SPE device was made and used to heat samples directly. ► MAE-μ-SPE was applied to the extraction of OPPs with non-polar solvent only. - Abstract: A single-step extraction-cleanup method, including microwave-assisted extraction (MAE) and micro-solid-phase extraction (μ-SPE), was developed for the extraction of ten organophosphorus pesticides in vegetable and fruit samples. Without adding any polar solvent, only one kind of non-polar solvent (hexane) was used as extraction solvent in the whole extraction step. Absorbing microwave μ-SPE device, was prepared by packing activated carbon with microporous polypropylene membrane envelope, and used as not only the sorbent in μ-SPE, but also the microwave absorption medium. Some experimental parameters effecting on extraction efficiency was investigated and optimized. 1.0 g of sample, 8 mL of hexane and three absorbing microwave μ-SPE devices were added in the microwave extraction vessel, the extraction was carried out under 400 W irradiation power at 60 °C for 10 min. The extracts obtained by MAE-μ-SPE were directly analyzed by GC–MS without any clean-up process. The recoveries were in the range of 93.5–104.6%, and the relative standard deviations were lower than 8.7%.

  4. An absorbing microwave micro-solid-phase extraction device used in non-polar solvent microwave-assisted extraction for the determination of organophosphorus pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ziming, E-mail: wangziming@jlu.edu.cn [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); College of Environment and Resources, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Zhao Xin; Xu Xu; Wu Lijie; Su Rui; Zhao Yajing; Jiang Chengfei; Zhang Hanqi [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Ma Qiang [Chinese Academy of Inspection and Quarantine, Beijing 100123 (China); Lu Chunmei [College of Technology Center, Jilin Entry-Exit Inspection and Quarantine Bureau, Changchun 130062 (China); Dong Deming [College of Environment and Resources, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2013-01-14

    Highlights: Black-Right-Pointing-Pointer An absorbing microwave {mu}-SPE device packed with activated carbon was used. Black-Right-Pointing-Pointer Absorbing microwave {mu}-SPE device was made and used to enrich the analytes. Black-Right-Pointing-Pointer Absorbing microwave {mu}-SPE device was made and used to heat samples directly. Black-Right-Pointing-Pointer MAE-{mu}-SPE was applied to the extraction of OPPs with non-polar solvent only. - Abstract: A single-step extraction-cleanup method, including microwave-assisted extraction (MAE) and micro-solid-phase extraction ({mu}-SPE), was developed for the extraction of ten organophosphorus pesticides in vegetable and fruit samples. Without adding any polar solvent, only one kind of non-polar solvent (hexane) was used as extraction solvent in the whole extraction step. Absorbing microwave {mu}-SPE device, was prepared by packing activated carbon with microporous polypropylene membrane envelope, and used as not only the sorbent in {mu}-SPE, but also the microwave absorption medium. Some experimental parameters effecting on extraction efficiency was investigated and optimized. 1.0 g of sample, 8 mL of hexane and three absorbing microwave {mu}-SPE devices were added in the microwave extraction vessel, the extraction was carried out under 400 W irradiation power at 60 Degree-Sign C for 10 min. The extracts obtained by MAE-{mu}-SPE were directly analyzed by GC-MS without any clean-up process. The recoveries were in the range of 93.5-104.6%, and the relative standard deviations were lower than 8.7%.

  5. Experimental Investigation of Evolution of Pore Structure in Longmaxi Marine Shale Using an Anhydrous Pyrolysis Technique

    Directory of Open Access Journals (Sweden)

    Zhaodong Xi

    2018-05-01

    Full Text Available To better understanding the evolutionary characteristics of pore structure in marine shale with high thermal maturity, a natural Longmaxi marine shale sample from south China with a high equivalent vitrinite reflectance value (Ro = 2.03% was selected to conduct an anhydrous pyrolysis experiment (500–750 °C, and six artificial shale samples (pyrolysis products spanning a maturity range from Ro = 2.47% to 4.87% were obtained. Experimental procedures included mercury intrusion, nitrogen adsorption, and carbon dioxide adsorption, and were used to characterize the pore structure. In addition, fractal theory was applied to analyze the heterogeneous pore structure. The results showed that this sample suite had large differences in macropore, mesopore, and micropore volume (PV, as well as specific surface area (SSA and pore size distributions (PSD, at different temperatures. Micropore, mesopore, and macropore content increased, from being unheated to 600 °C, which caused the pore structure to become more complex. The content of small diameter pores (micropores and fine mesopores, <10 nm decreased and pores with large diameters (large mesopores and macropores, >10 nm slightly increased from 600 to 750 °C. Fractal analysis showed that larger pore sizes had more complicated pore structure in this stage. The variance in pore structure for samples during pyrolysis was related to the further transformation of organic matter and PSD rearrangement. According to the data in this study, two stages were proposed for the pore evolution for marine shale with high thermal maturity.

  6. Preparation and characterization of 1,6 anhydrous Β-D-Glucopyranose from starch

    International Nuclear Information System (INIS)

    Alvarez Lopez, M.S.

    1991-01-01

    In order to prepare 2-deoxi-2-fluoride-D-glucosa (2FDG) in an inert form there are several synthesis methods, but the more interesting one for our study is based in a reaction from the 1,6 anhydrous, Β-D-glucopyranose (1,6AGP), in an attempt to compare the labelling efficiency rate of 2FDG with F-18, which is highly used in nuclear medicine. In the present paper the attainment of starch from white potatoe, infrared analysis of this starch and fusion point are included. Also results are compared with an analytical reactive standard. The process of preparation of 1,6AGP by pyrolysis of starch under reduced pressure, its separation and purification by crystallization and infrared characterization of 1,6AGP, nuclear magnetic resonance and mass spectrometry are also included. 10 kg. of potatoes were used, and 93059 g. ±5.8 of starch with an efficiency rate of 9.32 ±0.631; fusion point was 272 o C and there was a 9.83 ± 1.48 % of humidity. After the pyrolysis, crystallization an purification processes, 1.71 ±0.54 % of 1,6AGP were obtained. Later results of compound characterization, nuclear magnetic resonance, infrared and mass spectrometry were compared with a commercial product and it was proved that it corresponds to such pure compound. (Author)

  7. Anhydrous formic acid and acetic anhydride as solvent or additive in nonaqueous titrations.

    Science.gov (United States)

    Buvári-Barcza, A; Tóth, I; Barcza, L

    2005-09-01

    The use and importance of formic acid and acetic anhydride (Ac2O) is increasing in nonaqueous acid-base titrations, but their interaction with the solutes is poorly understood. This paper attempts to clarify the effect of the solvents; NMR and spectrophotometric investigations were done to reveal the interactions between some bases and the mentioned solvents. Anhydrous formic acid is a typical protogenic solvent but both the relative permittivity and acidity are higher than those of acetic acid (mostly used in assays of bases). These differences originate from the different chemical structures: liquid acetic acid contains basically cyclic dimers while formic acid forms linear associates. Ac2O is obviously not an acidic but an aprotic (very slightly protophilic) solvent, which supposedly dissociates slightly into acetyl (CH3CO+) and acetate (AcO-) ions. In fact, some bases react with Ac2O forming an associate: the Ac+ group is bound to the delta- charged atom of the reactant while AcO- is associated with the delta+ group at appropriate distance.

  8. Investigation of solubility of carbon dioxide in anhydrous milk fat by lab-scale manometric method.

    Science.gov (United States)

    Truong, Tuyen; Palmer, Martin; Bansal, Nidhi; Bhandari, Bhesh

    2017-12-15

    This study aims to examine the solubility of CO 2 in anhydrous milk fat (AMF) as functions of partial pressure, temperature, chemical composition and physical state of AMF. AMF was fractionated at 21°C to obtain stearin and olein fractions. The CO 2 solubility was measured using a home-made experimental apparatus based on changes of CO 2 partial pressures. The apparatus was found to be reliable as the measured and theoretical values based on the ideal gas law were comparable. The dissolved CO 2 concentration in AMF increased with an increase in CO 2 partial pressure (0-101kPa). The apparent CO 2 solubility coefficients (molkg -1 Pa -1 ) in the AMF were 5.75±0.16×10 -7 , 3.9±0.19×10 -7 and 1.19±0.14×10 -7 at 35, 24 and 4°C, respectively. Higher liquid oil proportions resulted in higher CO 2 solubility in the AMF. There was insignificant difference in the dissolved CO 2 concentration among the AMF, stearin and olein fractions in their liquid state at 40°C. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Vapor-phase etching of InP using anhydrous HCl and PH/sub 3/ gas

    International Nuclear Information System (INIS)

    Pak, K.; Koide, Y.; Imai, K.; Yoshida, A.; Nakamura, T.; Yasuda, Y.; Nishinaga, T.

    1986-01-01

    In situ etching of the substrate surface for vapor-phase epitaxy is a useful technique for obtaining a smooth and damage-free surface prior to the growth. Previous work showed that the incorporation of in situ etching of InP substrate with anhydrous HCl gas resulted in a significant improvement in the surface morphologies for MOVPE-grown InGaAs/InP and InP epitaxial layers. However, the experiment on the HCl etching of the InP substrate for a wide temperature range has not been performed as yet. In this note, the authors describe the effect of the substrate temperature on the etching morphology of InP substrate by using the anhydrous HCl and PH/sub 3/ gases. In the experiment, they used a standard MOVPE horizontal system. A quartz reactor tube in a 60 mm ID, 60 cm long, was employed

  10. Use of X-ray diffraction to quantify amorphous supplementary cementitious materials in anhydrous and hydrated blended cements

    International Nuclear Information System (INIS)

    Snellings, R.; Salze, A.; Scrivener, K.L.

    2014-01-01

    The content of individual amorphous supplementary cementitious materials (SCMs) in anhydrous and hydrated blended cements was quantified by the PONKCS [1] X-ray diffraction (XRD) method. The analytical precision and accuracy of the method were assessed through comparison to a series of mixes of known phase composition and of increasing complexity. A 2σ precision smaller than 2–3 wt.% and an accuracy better than 2 wt.% were achieved for SCMs in mixes with quartz, anhydrous Portland cement, and hydrated Portland cement. The extent of reaction of SCMs in hydrating binders measured by XRD was 1) internally consistent as confirmed through the standard addition method and 2) showed a linear correlation to the cumulative heat release as measured independently by isothermal conduction calorimetry. The advantages, limitations and applicability of the method are discussed with reference to existing methods that measure the degree of reaction of SCMs in blended cements

  11. Studying the response of CR-39 to radon in non-polar liquids above water by Monte Carlo simulation and measurement

    International Nuclear Information System (INIS)

    Rezaie, Mohammad Reza; Sohrabi, Mehdi; Negarestani, Ali

    2013-01-01

    The application of CR-39 has been extensive for measurement of radon and progeny in air of dwellings, but limited as regards to measurements of radon in water. In this paper, a new method is introduced for efficient measurement of radon in water by registering alpha particle tracks in a CR-39 detector placed in a non-polar medium such as cyclohexane, hexane and olive oil when each mixed with water, then separated and fixed above water, as a two-phase media. The method introduced here is however different from the widely used liquid - liquid extraction technique by liquid scintillation spectrometry since it is a passive detection method (CR-39) in a non-polar liquid with enhanced absorption of radon in the liquid, it has a capability for long sample counting to decrease the minimum detection limit (MDL), it does not require sophisticated low light counting systems, and it has the potential for simultaneous measurements of large number of samples for large-scale applications. It also has a low cost and is readily available. A new Monte Carlo calculation of energy-distance travelled by alphas from radon and progeny in a medium was also investigated. The sensitivity of CR-39 detector to radon and progeny in water was determined under two conditions; in a single-phase and two-phase media. In a single-phase medium, CR-39 is directly placed either in air, water, cyclohexane, hexane or olive oil. When CR-39 is placed directly in water, its sensitivity is (2.4 ± 0.1) × 10 −4 (track/cm 2 )/(Bq.d/m 3 ). In the two-phase media, CR-39 is placed either in cyclohexane, hexane or olive oil when each is fixed above water. The sensitivities in the two-phase media are significantly enhanced and are respectively (1.98 ± 0.10) × 10 −2 , (2.8 ± 0.15) × 10 −2 and (2.86 ± 0.15) × 10 −2 (track/cm 2 )/(Bq.d/m 3 ). The sensitivies are about 76, 82 and 110 times more than that of when CR-39 is directly placed in water. The new method is a novel alternative for radon

  12. Sorption of polar and nonpolar organic contaminants by oil-contaminated soil.

    Science.gov (United States)

    Chen, Hong; Chen, Shuo; Quan, Xie; Zhao, Huimin; Zhang, Yaobin

    2008-12-01

    Sorption of nonpolar (phenanthrene and butylate) and polar (atrazine and diuron) organic chemicals to oil-contaminated soil was examined to investigate oil effects on sorption of organic chemicals and to derive oil-water distribution coefficients (K(oil)). The resulting oil-contaminated soil-water distribution coefficients (K(d)) for phenanthrene demonstrated sorption-enhancing effects at both lower and higher oil concentrations (C(oil)) but sorption-reducing (competitive) effects at intermediate C(oil) (approximately 1 g kg(-1)). Rationalization of the different dominant effects was attempted in terms of the relative aliphatic carbon content which determines the accessibility of the aromatic cores to phenanthrene. Little or no competitive effect occurred for butylate because its sorption was dominated by partitioning. For atrazine and diuron, the changes in K(d) at C(oil) above approximately 1 g kg(-1) were negligible, indicating that the presently investigated oil has little or no effect on the two tested compounds even though the polarity of the oil is much less than soil organic matter (SOM). Therefore, specific interactions with the active groups (aromatic and polar domains) are dominantly responsible for the sorption of polar sorbates, and thus their sorption is controlled by available sorption sites. This study showed that the oil has the potential to be a dominant sorptive phase for nonpolar pollutants when compared to SOM, but hardly so for polar compounds. The results may aid in a better understanding of the role of the aliphatic and aromatic domains in sorption of nonpolar and polar organic pollutants.

  13. In Vitro Anticancer Activity of a Nonpolar Fraction from Gynostemma pentaphyllum (Thunb. Makino

    Directory of Open Access Journals (Sweden)

    Yantao Li

    2016-01-01

    Full Text Available Gynostemma pentaphyllum (Thunb. Makino (GpM has been widely used in traditional Chinese medicine (TCM for the treatment of various diseases including cancer. Most previous studies have focused primarily on polar fractions of GpM for anticancer activities. In this study, a nonpolar fraction EA1.3A from GpM showed potent growth inhibitory activities against four cancer cell lines with IC50 ranging from 31.62 μg/mL to 38.02 μg/mL. Furthermore, EA1.3A also inhibited the growth of breast cancer cell MDA-MB-453 time-dependently, as well as its colony formation ability. EA1.3A induced apoptosis on MDA-MB-453 cells both dose-dependently and time-dependently as analyzed by flow cytometry and verified by western blotting analysis of apoptosis marker cleaved nuclear poly(ADP-ribose polymerase (cPARP. Additionally, EA1.3A induced cell cycle arrest in G0/G1 phase. Chemical components analysis of EA1.3A by GC-MS revealed that this nonpolar fraction from GpM contains 10 compounds including four alkaloids, three organic esters, two terpenes, and one catechol substance, and all these compounds have not been reported in GpM. In summary, the nonpolar fraction EA1.3A from GpM inhibited cancer cell growth through induction of apoptosis and regulation of cell cycle progression. Our study shed light on new chemical bases for the anticancer activities of GpM and feasibilities to develop new anticancer agents from this widely used medicinal plant.

  14. Structural anisotropy of nonpolar and semipolar InN epitaxial layers

    Science.gov (United States)

    Darakchieva, V.; Xie, M.-Y.; Franco, N.; Giuliani, F.; Nunes, B.; Alves, E.; Hsiao, C. L.; Chen, L. C.; Yamaguchi, T.; Takagi, Y.; Kawashima, K.; Nanishi, Y.

    2010-10-01

    We present a detailed study of the structural characteristics of molecular beam epitaxy grown nonpolar InN films with a- and m-plane surface orientations on r-plane sapphire and (100) γ-LiAlO2, respectively, and semipolar (101¯1) InN grown on r-plane sapphire. The on-axis rocking curve (RC) widths were found to exhibit anisotropic dependence on the azimuth angle with minima at InN [0001] for the a-plane films, and maxima at InN [0001] for the m-plane and semipolar films. The different contributions to the RC broadening are analyzed and discussed. The finite size of the crystallites and extended defects are suggested to be the dominant factors determining the RC anisotropy in a-plane InN, while surface roughness and curvature could not play a major role. Furthermore, strategy to reduce the anisotropy and magnitude of the tilt and minimize defect densities in a-plane InN films is suggested. In contrast to the nonpolar films, the semipolar InN was found to contain two domains nucleating on zinc-blende InN(111)A and InN(111)B faces. These two wurtzite domains develop with different growth rates, which was suggested to be a consequence of their different polarity. Both, a- and m-plane InN films have basal stacking fault densities similar or even lower compared to nonpolar InN grown on free-standing GaN substrates, indicating good prospects of heteroepitaxy on foreign substrates for the growth of InN-based devices.

  15. Structural anisotropy of nonpolar and semipolar InN epitaxial layers

    International Nuclear Information System (INIS)

    Darakchieva, V.; Xie, M.-Y.; Franco, N.; Alves, E.; Giuliani, F.; Nunes, B.; Hsiao, C. L.; Chen, L. C.; Yamaguchi, T.; Takagi, Y.; Kawashima, K.; Nanishi, Y.

    2010-01-01

    We present a detailed study of the structural characteristics of molecular beam epitaxy grown nonpolar InN films with a- and m-plane surface orientations on r-plane sapphire and (100) γ-LiAlO 2 , respectively, and semipolar (1011) InN grown on r-plane sapphire. The on-axis rocking curve (RC) widths were found to exhibit anisotropic dependence on the azimuth angle with minima at InN [0001] for the a-plane films, and maxima at InN [0001] for the m-plane and semipolar films. The different contributions to the RC broadening are analyzed and discussed. The finite size of the crystallites and extended defects are suggested to be the dominant factors determining the RC anisotropy in a-plane InN, while surface roughness and curvature could not play a major role. Furthermore, strategy to reduce the anisotropy and magnitude of the tilt and minimize defect densities in a-plane InN films is suggested. In contrast to the nonpolar films, the semipolar InN was found to contain two domains nucleating on zinc-blende InN(111)A and InN(111)B faces. These two wurtzite domains develop with different growth rates, which was suggested to be a consequence of their different polarity. Both, a- and m-plane InN films have basal stacking fault densities similar or even lower compared to nonpolar InN grown on free-standing GaN substrates, indicating good prospects of heteroepitaxy on foreign substrates for the growth of InN-based devices.

  16. High temperature proton exchange membranes prepared from epoxycyclohexylethyltrimethoxysilane and amino trimethylene phosphonic acid as anhydrous proton conductors

    International Nuclear Information System (INIS)

    Chen, Cheng; Shen, Chunhui; Kong, Gengjin; Gao, Shanjun

    2013-01-01

    High temperature anhydrous proton exchange membranes based on phosphonic acid were prepared from epoxycyclohexylethyltrimethoxysilane (EHTMS) and amino trimethylene phosphonic acid (ATMP) by sol–gel process. The structures and properties of membranes with different phosphonic acid content were extensively characterized by FTIR, TG-DSC and XRD. Their proton conductivity under dry condition was also investigated under different temperature. The results show that the proton conductivity of the prepared membranes strongly depends on temperature, and the proton conductivity ranges from 8.81 × 10 −5 S cm −1 at 20 °C to 4.65 × 10 −2 S cm −1 at 140 °C under anhydrous condition. It indicates that the increasing temperature is favorable for congregating of the grafted–PO 3 H 2 and increasing of the proton mobility. In addition, from the results of AFM images, it was confirmed that the continuous distribution of phosphonic acid groups is favorable for the formation of the proton transport channel, which can significantly enhance the proton conductivity of the membranes. Highlights: ► Hybrid membranes of Epoxycyclohexylethyltrimethoxysilane and Amino trimethylene phosphonic acid. ► The proton conductivity is 4.65 × 10 −2 S cm −1 at 140 °C under anhydrous condition. ► Continuous uniform distributions of phosphonic acid groups can be observed by AFM. ► There could be hydrogen bond network within high temperature membranes

  17. Anhydrate to hydrate solid-state transformations of carbamazepine and nitrofurantoin in biorelevant media studied in situ using time-resolved synchrotron X-ray diffraction

    DEFF Research Database (Denmark)

    Bøtker, Johan Peter; Rantanen, Jukka; Arnfast, Lærke

    2016-01-01

    with different biorelevant media, simulated fasted and fed state intestinal fluids containing bile salt and dioleoylphosphatidylcholine (DOPC) micelles, DOPC/sodium dodecyl sulfate (SDS) mixture, bile salt solution and water. Two anhydrate compounds (carbamazepine, CBZ and nitrofurantoin, NF) with different...

  18. Dispersing surface-modified imogolite nanotubes in polar and non-polar solvents

    Science.gov (United States)

    Li, Ming; Brant, Jonathan A.

    2018-02-01

    Furthering the development of nanocomposite structures, namely membranes for water treatment applications, requires that methods be developed to ensure nanoparticle dispersion in polar and non-polar solvents, as both are widely used in associated synthesis techniques. Here, we report on a two-step method to graft polyvinylpyrrolidone (PVP), and a one-step method for octadecylphosphonic acid (OPA), onto the outer surfaces of imogolite nanotubes. The goal of these approaches was to improve and maintain nanotube dispersion in polymer compatible polar and non-polar solvents. The PVP coating modified the imogolite surface charge from positive to weakly negative at pH ≤ 9; the OPA made it weakly positive at acidic pH values to negative at pH ≥ 7. The PVP surface coating stabilized the nanotubes through steric hindrance in polar protic, dipolar aprotic, and chloroform. In difference to the PVP, the OPA surface coating allowed the nanotubes to be dispersed in n-hexane and chloroform, but not in the polar solvents. The lack of miscibility in the polar solvents, as well as the better dispersion in n-hexane, was attributed to the stronger hydrophobicity of the OPA polymer relative to the PVP. [Figure not available: see fulltext.

  19. Polarization of eigenmodes in laser diode waveguides on semipolar and nonpolar GaN

    Energy Technology Data Exchange (ETDEWEB)

    Rass, Jens; Vogt, Patrick [Institute of Solid State Physics, Technische Universitaet Berlin (Germany); Wernicke, Tim; Einfeldt, Sven; Weyers, Markus [Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Berlin (Germany); Scheibenzuber, Wolfgang G.; Schwarz, Ulrich T. [Department of Physics, Regensburg University (Germany); Kupec, Jan [Integrated Systems Laboratory, ETH Zurich (Switzerland); Witzigmann, Bernd [Computational Electronics and Photonics Group, University of Kassel (Germany); Kneissl, Michael [Institute of Solid State Physics, Technische Universitaet Berlin (Germany); Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Berlin (Germany)

    2010-02-15

    Recent calculations of the eigenmodes in waveguides grown on semipolar GaN suggest that the optical polarization of the emitted light as well as the optical gain depends on the orientation of the resonator. Our measurements on separate confinement heterostructures on semipolar (11 anti 22) and (10 anti 12) GaN show that for laser resonators along the semipolar [11 anti 2 anti 3 ] and [0 anti 111] directions (i.e. the projection of the c-axis onto the plane of growth) the threshold for amplified spontaneous emission is lower than for the nonpolar direction and that the stimulated emission is linearly polarized as TE mode. For the waveguide structures along the nonpolar [1 anti 100] or [11 anti 20] direction on the other hand, birefringence and anisotropy of the optical gain in the plane of growth leads not only to a higher threshold but also to a rotation of the optical polarization which is not any more TE- or TM-polarized but influenced by the ordinary and extraordinary refractive index of the material. We observe stimulated emission into a mode which is linearly polarized in extraordinarydirection nearly parallel to the c-axis. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Growth on nonpolar and semipolar GaN: The substrate dilemma

    Energy Technology Data Exchange (ETDEWEB)

    Wernicke, T.; Weyers, M. [Ferdinand-Braun-Institute, Berlin (Germany); Kneissl, M. [Ferdinand-Braun-Institute, Berlin (Germany); Institute of Solid State Physics, TU Berlin (Germany)

    2009-07-01

    Growth of nonpolar and semipolar GaN is very promising for achieving green laser diodes (LDs). However, the choice of the substrate is a difficult one: Heteroepitaxial growth on sapphire, SiC, LiAlO{sub 2} yields GaN films with a poor surface quality and high defect densities. On the other hand non- and semipolar bulk GaN substrates provide excellent crystal quality, but are so far only available in very small sizes. In this paper hetero- and homoepitaxial growth is compared. For all heteroepitaxially grown semi- and nonpolar GaN layers threading dislocations (TD) and basal plane stacking faults (BSF) can be found. There are four possible mechanisms for the generation of BSF: Growth of the N-polar basal plane, formation during nucleation at substrate steps, formation at the coalescence front of differently stacked nucleation islands, and generation at planar defects occurring in m-plane GaN on LiAlO{sub 2}. BSF induce surface roughening and are associated with partial dislocations causing nonradiative recombination. Thus they affect the performance of devices. We show that BSFs and TDs can be reduced by epitaxial lateral overgrowth resulting in several micrometer wide defect free areas. However, for LEDs larger defect-free areas are required. GaN layers grown on bulk GaN substrates exhibit a high crystal quality, but show in many cases long-range surface structures with a height of {approx}1{mu}m.

  1. Investigation of blue luminescence in Mg-doped nonpolar a-plane GaN

    International Nuclear Information System (INIS)

    Kim, Hogyoung; Song, Keun Man

    2014-01-01

    The temperature-dependent optical characteristics of blue luminescence (BL) band in Mg-doped nonpolar a-plane GaN films were investigated using photoluminescence (PL) measurements. For the sample with the highest Cp 2 Mg/TMGa ([Mg]/[Ga]) molar ratio, the BL band was shown to have two distinct peaks, one at about 2.95 eV and the other at about 2.75 eV, which were associated with the donor–acceptor pair (DAP) transitions between the one shallow Mg acceptor level and the two different deep donor levels. In contrast, a single broad BL band was observed for all other samples. Strong potential fluctuations caused by high compensation level in the sample with the highest [Mg]/[Ga] molar ratio might localize the carriers related to the 2.75 eV band, leading to the different emission characteristics in BL band as compared to other samples. -- Highlights: • The temperature-dependent optical characteristics of blue luminescence (BL) in Mg-doped nonpolar a-plane GaN were investigated using photoluminescence (PL) measurements. • At the highest [Mg]/[Ga] molar ratio, the BL was observed to have two distinct peaks at low temperatures. • The BL was associated with the one shallow Mg acceptor level and the two different Mg-related deep donor levels. • Strong potential fluctuations caused by high compensation level might localize the carriers

  2. Investigation of blue luminescence in Mg-doped nonpolar a-plane GaN

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hogyoung [Department of Optometry, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Song, Keun Man, E-mail: skmmec@gmail.com [Korea Advanced Nano Fab Center, Suwon, Gyeonggi 443-770 (Korea, Republic of)

    2014-01-15

    The temperature-dependent optical characteristics of blue luminescence (BL) band in Mg-doped nonpolar a-plane GaN films were investigated using photoluminescence (PL) measurements. For the sample with the highest Cp{sub 2}Mg/TMGa ([Mg]/[Ga]) molar ratio, the BL band was shown to have two distinct peaks, one at about 2.95 eV and the other at about 2.75 eV, which were associated with the donor–acceptor pair (DAP) transitions between the one shallow Mg acceptor level and the two different deep donor levels. In contrast, a single broad BL band was observed for all other samples. Strong potential fluctuations caused by high compensation level in the sample with the highest [Mg]/[Ga] molar ratio might localize the carriers related to the 2.75 eV band, leading to the different emission characteristics in BL band as compared to other samples. -- Highlights: • The temperature-dependent optical characteristics of blue luminescence (BL) in Mg-doped nonpolar a-plane GaN were investigated using photoluminescence (PL) measurements. • At the highest [Mg]/[Ga] molar ratio, the BL was observed to have two distinct peaks at low temperatures. • The BL was associated with the one shallow Mg acceptor level and the two different Mg-related deep donor levels. • Strong potential fluctuations caused by high compensation level might localize the carriers.

  3. Broadband non-polarizing beam splitter based on guided mode resonance effect

    International Nuclear Information System (INIS)

    Ma Jian-Yong; Xu Cheng; Qiang Ying-Huai; Zhu Ya-Bo

    2011-01-01

    A broadband non-polarizing beam splitter (NPBS) operating in the telecommunication C+L band is designed by using the guided mode resonance effect of periodic silicon-on-insulator (SOI) elements. It is shown that this double layer SOI structure can provide ∼50/50 beam ratio with the maximum divergences between reflection and transmission being less than 8% over the spectrum of 1.4 μm∼1.7 μm and 1% in the telecommunication band for both TE and TM polarizations. The physical basis of this broadband non-polarizing property is on the simultaneous excitation of the TE and TM strong modulation waveguide modes near the designed spectrum band. Meanwhile, the electric field distributions for both TE and TM polarizations verify the resonant origin of spectrum in the periodic SOI structure. Furthermore, it is demonstrated with our calculations that the beam splitter proposed here is tolerant to the deviations of incident angle and structure parameters, which make it very easy to be fabricated with current IC technology. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  4. Detection of electrically neutral and nonpolar molecules in ionic solutions using silicon nanowires

    Science.gov (United States)

    Wu, Ying-Pin; Chu, Chia-Jung; Tsai, Li-Chu; Su, Ya-Wen; Chen, Pei-Hua; Moodley, Mathew K.; Huang, Ding; Chen, Yit-Tsong; Yang, Ying-Jay; Chen, Chii-Dong

    2017-04-01

    We report on a technique that can extend the use of nanowire sensors to the detection of interactions involving nonpolar and neutral molecules in an ionic solution environment. This technique makes use of the fact that molecular interactions result in a change in the permittivity of the molecules involved. For the interactions taking place at the surface of nanowires, this permittivity change can be determined from the analysis of the measured complex impedance of the nanowire. To demonstrate this technique, histidine was detected using different charge polarities controlled by the pH value of the solution. This included the detection of electrically neutral histidine at a sensitivity of 1 pM. Furthermore, it is shown that nonpolar molecules, such as hexane, can also be detected. The technique is applicable to the use of nanowires with and without a surface-insulating oxide. We show that information about the changes in amplitude and the phase of the complex impedance reveals the fundamental characteristics of the molecular interactions, including the molecular field and the permittivity.

  5. Nonpolar III-nitride vertical-cavity surface-emitting lasers incorporating an ion implanted aperture

    KAUST Repository

    Leonard, J. T.; Cohen, D. A.; Yonkee, B. P.; Farrell, R. M.; Margalith, T.; Lee, S.; DenBaars, S. P.; Speck, J. S.; Nakamura, S.

    2015-01-01

    © 2015 AIP Publishing LLC. We report on our recent progress in improving the performance of nonpolar III-nitride vertical-cavity surface-emitting lasers (VCSELs) by using an Al ion implanted aperture and employing a multi-layer electron-beam evaporated ITO intracavity contact. The use of an ion implanted aperture improves the lateral confinement over SiNx apertures by enabling a planar ITO design, while the multi-layer ITO contact minimizes scattering losses due to its epitaxially smooth morphology. The reported VCSEL has 10 QWs, with a 3nm quantum well width, 1nm barriers, a 5nm electron-blocking layer, and a 6.95- λ total cavity thickness. These advances yield a single longitudinal mode 406nm nonpolar VCSEL with a low threshold current density (∼16kA/cm2), a peak output power of ∼12μW, and a 100% polarization ratio. The lasing in the current aperture is observed to be spatially non-uniform, which is likely a result of filamentation caused by non-uniform current spreading, lateral optical confinement, contact resistance, and absorption loss.

  6. Non-Polar Natural Products from Bromelia laciniosa, Neoglaziovia variegata and Encholirium spectabile (Bromeliaceae

    Directory of Open Access Journals (Sweden)

    Ole Johan Juvik

    2017-09-01

    Full Text Available Extensive regional droughts are already a major problem on all inhabited continents and severe regional droughts are expected to become an increasing and extended problem in the future. Consequently, extended use of available drought resistant food plants should be encouraged. Bromelia laciniosa, Neoglaziovia variegata and Encholirium spectabile are excellent candidates in that respect because they are established drought resistant edible plants from the semi-arid Caatinga region. From a food safety perspective, increased utilization of these plants would necessitate detailed knowledge about their chemical constituents. However, their chemical compositions have previously not been determined. For the first time, the non-polar constituents of B. laciniosa, N. variegata and E. spectabile have been identified. This is the first thorough report on natural products from N. variegata, E. spectabile, and B. laciniosa. Altogether, 20 non-polar natural products were characterized. The identifications were based on hyphenated gas chromatography-high resolution mass spectrometry (GC-HRMS and supported by 1D and 2D Nuclear Magnetic Resonance (NMR plant metabolomics.

  7. Nonpolar III-nitride vertical-cavity surface-emitting lasers incorporating an ion implanted aperture

    KAUST Repository

    Leonard, J. T.

    2015-07-06

    © 2015 AIP Publishing LLC. We report on our recent progress in improving the performance of nonpolar III-nitride vertical-cavity surface-emitting lasers (VCSELs) by using an Al ion implanted aperture and employing a multi-layer electron-beam evaporated ITO intracavity contact. The use of an ion implanted aperture improves the lateral confinement over SiNx apertures by enabling a planar ITO design, while the multi-layer ITO contact minimizes scattering losses due to its epitaxially smooth morphology. The reported VCSEL has 10 QWs, with a 3nm quantum well width, 1nm barriers, a 5nm electron-blocking layer, and a 6.95- λ total cavity thickness. These advances yield a single longitudinal mode 406nm nonpolar VCSEL with a low threshold current density (∼16kA/cm2), a peak output power of ∼12μW, and a 100% polarization ratio. The lasing in the current aperture is observed to be spatially non-uniform, which is likely a result of filamentation caused by non-uniform current spreading, lateral optical confinement, contact resistance, and absorption loss.

  8. Broadband non-polarizing beam splitter based on guided mode resonance effect

    Science.gov (United States)

    Ma, Jian-Yong; Xu, Cheng; Qiang, Ying-Huai; Zhu, Ya-Bo

    2011-10-01

    A broadband non-polarizing beam splitter (NPBS) operating in the telecommunication C+L band is designed by using the guided mode resonance effect of periodic silicon-on-insulator (SOI) elements. It is shown that this double layer SOI structure can provide ~50/50 beam ratio with the maximum divergences between reflection and transmission being less than 8% over the spectrum of 1.4 μm~1.7 μm and 1% in the telecommunication band for both TE and TM polarizations. The physical basis of this broadband non-polarizing property is on the simultaneous excitation of the TE and TM strong modulation waveguide modes near the designed spectrum band. Meanwhile, the electric field distributions for both TE and TM polarizations verify the resonant origin of spectrum in the periodic SOI structure. Furthermore, it is demonstrated with our calculations that the beam splitter proposed here is tolerant to the deviations of incident angle and structure parameters, which make it very easy to be fabricated with current IC technology.

  9. A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces.

    Science.gov (United States)

    Yu, Liping; Zunger, Alex

    2014-10-13

    The discovery of conductivity and magnetism at the polar-nonpolar interfaces of insulating nonmagnetic oxides such as LaAlO3 and SrTiO3 has raised prospects for attaining interfacial functionalities absent in the component materials. Yet, the microscopic origin of such emergent phenomena remains unclear, posing obstacles to design of improved functionalities. Here we present first principles calculations of electronic and defect properties of LaAlO3/SrTiO3 interfaces and reveal a unifying mechanism for the origins of both conductivity and magnetism. We demonstrate that the polar discontinuity across the interface triggers thermodynamically the spontaneous formation of certain defects that in turn cancel the polar field induced by the polar discontinuity. The ionization of the spontaneously formed surface oxygen vacancy defects leads to interface conductivity, whereas the unionized Ti-on-Al antisite defects lead to interface magnetism. The proposed mechanism suggests practical design principles for inducing and controlling both conductivity and magnetism at general polar-nonpolar interfaces.

  10. The atomic structure of polar and non-polar InGaN quantum wells and the green gap problem

    Energy Technology Data Exchange (ETDEWEB)

    Humphreys, C.J., E-mail: colin.humphreys@msm.cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Griffiths, J.T., E-mail: jg641@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Tang, F., E-mail: ft274@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Oehler, F., E-mail: fabrice.oehler@lpn.cnrs.fr [CNRS/C2N, Paris Sud University, Route de Nozay, 91460 Marcoussis (France); Findlay, S.D., E-mail: scott.findlay@monash.edu [School of Physics and Astronomy, Monash University, Victoria 3800 (Australia); Zheng, C., E-mail: changlin.zheng@monash.edu [Monash Centre for Electron Microscopy, Monash University, Victoria 3800 (Australia); Etheridge, J., E-mail: joanne.etheridge@mcem.monash.edu [Department of Materials Science and Engineering, Monash University, Victoria 3800 (Australia); Martin, T.L., E-mail: tomas.martin@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Bagot, P.A.J., E-mail: paul.bagot@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Moody, M.P., E-mail: michael.moody@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Sutherland, D., E-mail: danny.sutherland@manchester.ac.uk [School of Physics and Astronomy, Photon Science Institute, University of Manchester, Manchester M13 9PL (United Kingdom); Dawson, P., E-mail: philip.dawson@manchester.ac.uk [School of Physics and Astronomy, Photon Science Institute, University of Manchester, Manchester M13 9PL (United Kingdom); Schulz, S., E-mail: stefan.schulz@tyndall.ie [Tyndall National Institute, Lee Maltings Complex, Dyke Parade, Cork (Ireland); and others

    2017-05-15

    Highlights: • We have studied the atomic structure of polar and non-polar InGaN quantum wells. • The non-polar (11-20) InGaN quantum wells contain indium-rich clusters, unlike the polar (0001) quantum wells. • The electrons and holes in the quantum wells are localised by different mechanisms. - Abstract: We have used high resolution transmission electron microscopy (HRTEM), aberration-corrected quantitative scanning transmission electron microscopy (Q-STEM), atom probe tomography (APT) and X-ray diffraction (XRD) to study the atomic structure of (0001) polar and (11-20) non-polar InGaN quantum wells (QWs). This paper provides an overview of the results. Polar (0001) InGaN in QWs is a random alloy, with In replacing Ga randomly. The InGaN QWs have atomic height interface steps, resulting in QW width fluctuations. The electrons are localised at the top QW interface by the built-in electric field and the well-width fluctuations, with a localisation energy of typically 20 meV. The holes are localised near the bottom QW interface, by indium fluctuations in the random alloy, with a localisation energy of typically 60 meV. On the other hand, the non-polar (11-20) InGaN QWs contain nanometre-scale indium-rich clusters which we suggest localise the carriers and produce longer wavelength (lower energy) emission than from random alloy non-polar InGaN QWs of the same average composition. The reason for the indium-rich clusters in non-polar (11-20) InGaN QWs is not yet clear, but may be connected to the lower QW growth temperature for the (11-20) InGaN QWs compared to the (0001) polar InGaN QWs.

  11. Indium gallium nitride/gallium nitride quantum wells grown on polar and nonpolar gallium nitride substrates

    Science.gov (United States)

    Lai, Kun-Yu

    Nonpolar (m-plane or a-plane) gallium nitride (GaN) is predicted to be a potential substrate material to improve luminous efficiencies of nitride-based quantum wells (QWs). Numerical calculations indicated that the spontaneous emission rate in a single In0.15Ga0.85N/GaN QW could be improved by ˜2.2 times if the polarization-induced internal field was avoided by epitaxial deposition on nonpolar substrates. A challenge for nonpolar GaN is the limited size (less than 10x10 mm2) of substrates, which was addressed by expansion during the regrowth by Hydride Vapor Phase Epitaxy (HVPE). Subsurface damage in GaN substrates were reduced by annealing with NH3 and N2 at 950°C for 60 minutes. It was additionally found that the variation of m-plane QWs' emission properties was significantly increased when the substrate miscut toward a-axis was increased from 0° to 0.1°. InGaN/GaN QWs were grown by Metalorganic Chemical Vapor Deposition (MOCVD) on c-plane and m-plane GaN substrates. The QWs were studied by cathodoluminescence spectroscopy with different incident electron beam probe currents (0.1 nA ˜ 1000 nA). Lower emission intensities and longer peak wavelengths from c-plane QWs were attributed to the Quantum-confined Stark Effect (QCSE). The emission intensity ratios of m-plane QWs to c-plane QWs decreased from 3.04 at 1 nA to 1.53 at 1000 nA. This was identified as the stronger screening effects of QCSE at higher current densities in c-plane QWs. To further investigate these effects in a fabricated structure, biased photoluminescence measurements were performed on m-plane InGaN/GaN QWs. The purpose was to detect the possible internal fields induced by the dot-like structure in the InGaN layer through the response of these internal fields under externally applied fields. No energy shifts of the QWs were observed, which was attributed to strong surface leakage currents.

  12. Constraining the Timescales of Rehydration in Nominally Anhydrous Minerals Using 3D Numerical Diffusion Models

    Science.gov (United States)

    Lynn, K. J.; Warren, J. M.

    2017-12-01

    Nominally anhydrous minerals (NAMs) are important for characterizing deep-Earth water reservoirs, but the water contents of olivine (ol), orthopyroxene (opx), and clinopyroxene (cpx) in peridotites generally do not reflect mantle equilibrium conditions. Ol is typically "dry" and decoupled from H in cpx and opx, which is inconsistent with models of partial melting and/or diffusive loss of H during upwelling beneath mid-ocean ridges. The rehydration of mantle pyroxenes via late-stage re-fertilization has been invoked to explain their relatively high water contents. Here, we use sophisticated 3D diffusion models (after Shea et al., 2015, Am Min) of H in ol, opx, and cpx to investigate the timescales of rehydration across a range of conditions relevant for melt-rock interaction and serpentinization of peridotites. Numerical crystals with 1 mm c-axis lengths and realistic crystal morphologies are modeled using recent H diffusivities that account for compositional variation and diffusion anisotropy. Models were run over timescales of minutes to millions of years and temperatures from 300 to 1200°C. Our 3D models show that, at the high-T end of the range, H concentrations in the cores of NAMs are partially re-equilibrated in as little as a few minutes, and completely re-equilibrated within hours to weeks. At low-T (300°C), serpentinization can induce considerable diffusion in cpx and opx. H contents are 30% re-equilibrated after continuous exposure to hydrothermal fluids for 102 and 105 years, respectively, which is inconsistent with previous interpretations that there is no effect on H in opx under similar conditions. Ol is unaffected after 1 Myr due to the slower diffusivity of the proton-vacancy mechanism at 300°C (2-4 log units lower than for opx). In the middle of the T range (700-1000°C), rehydration of opx and cpx occurs over hours to days, while ol is somewhat slower to respond (days to weeks), potentially allowing the decoupling observed in natural samples to

  13. Band offsets of non-polar A-plane GaN/AlN and AlN/GaN heterostructures measured by X-ray photoemission spectroscopy.

    Science.gov (United States)

    Sang, Ling; Zhu, Qin Sheng; Yang, Shao Yan; Liu, Gui Peng; Li, Hui Jie; Wei, Hong Yuan; Jiao, Chun Mei; Liu, Shu Man; Wang, Zhan Guo; Zhou, Xiao Wei; Mao, Wei; Hao, Yue; Shen, Bo

    2014-01-01

    The band offsets of non-polar A-plane GaN/AlN and AlN/GaN heterojunctions are measured by X-ray photoemission spectroscopy. A large forward-backward asymmetry is observed in the non-polar GaN/AlN and AlN/GaN heterojunctions. The valence-band offsets in the non-polar A-plane GaN/AlN and AlN/GaN heterojunctions are determined to be 1.33 ± 0.16 and 0.73 ± 0.16 eV, respectively. The large valence-band offset difference of 0.6 eV between the non-polar GaN/AlN and AlN/GaN heterojunctions is considered to be due to piezoelectric strain effect in the non-polar heterojunction overlayers.

  14. High temperature proton exchange membranes prepared from epoxycyclohexylethyltrimethoxysilane and amino trimethylene phosphonic acid as anhydrous proton conductors

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Cheng [Department of Polymer Materials and Engineering, School of Material Science and Engineering, Wuhan University of Technology, No. 122 Luoshi Road, Wuhan 430070 (China); Shen, Chunhui, E-mail: shenchunhui@whut.edu.cn [Department of Polymer Materials and Engineering, School of Material Science and Engineering, Wuhan University of Technology, No. 122 Luoshi Road, Wuhan 430070 (China); Kong, Gengjin; Gao, Shanjun [Department of Polymer Materials and Engineering, School of Material Science and Engineering, Wuhan University of Technology, No. 122 Luoshi Road, Wuhan 430070 (China)

    2013-06-15

    High temperature anhydrous proton exchange membranes based on phosphonic acid were prepared from epoxycyclohexylethyltrimethoxysilane (EHTMS) and amino trimethylene phosphonic acid (ATMP) by sol–gel process. The structures and properties of membranes with different phosphonic acid content were extensively characterized by FTIR, TG-DSC and XRD. Their proton conductivity under dry condition was also investigated under different temperature. The results show that the proton conductivity of the prepared membranes strongly depends on temperature, and the proton conductivity ranges from 8.81 × 10{sup −5} S cm{sup −1} at 20 °C to 4.65 × 10{sup −2} S cm{sup −1} at 140 °C under anhydrous condition. It indicates that the increasing temperature is favorable for congregating of the grafted–PO{sub 3}H{sub 2} and increasing of the proton mobility. In addition, from the results of AFM images, it was confirmed that the continuous distribution of phosphonic acid groups is favorable for the formation of the proton transport channel, which can significantly enhance the proton conductivity of the membranes. Highlights: ► Hybrid membranes of Epoxycyclohexylethyltrimethoxysilane and Amino trimethylene phosphonic acid. ► The proton conductivity is 4.65 × 10{sup −2} S cm{sup −1} at 140 °C under anhydrous condition. ► Continuous uniform distributions of phosphonic acid groups can be observed by AFM. ► There could be hydrogen bond network within high temperature membranes.

  15. Non-polarized cytokine profile of a long-term non-progressor HIV infected patient.

    Science.gov (United States)

    Pina, Ana Flávia; Matos, Vanessa Terezinha Gubert de; Bonin, Camila Mareti; Dal Fabbro, Márcia Maria Ferrairo Janini; Tozetti, Inês Aparecida

    The HIV-1 initial viral infection may present diverse clinical and laboratory course and lead to rapid, intermediate, or long-term progression. Among the group of non-progressors, the elite controllers are those who control the infection most effectively, in the absence of antiretroviral therapy (ART). In this paper, the TH1, TH2 and TH17 cytokines profiles are described, as well as clinical and laboratory aspects of an HIV-infected patient with undetectable viral load without antiretroviral therapy. Production of IL-6, IL-10, TNF-α, IFN-γ, and IL-17 was detected; in contrast IL-4 was identified. Host-related factors could help explain such a level of infection control, namely the differentiated modulation of the cellular immune response and a non-polarized cytokine response of the TH1 and TH2 profiles. Copyright © 2018 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. All rights reserved.

  16. Relation between the characteristic molecular volume and hydrophobicity of nonpolar molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sedov, Igor A., E-mail: igor_sedov@inbox.ru; Solomonov, Boris N., E-mail: boris.solomonov@ksu.r

    2010-09-15

    Experimental values of the Gibbs free energies of hydration for a set of nonpolar or very slightly polar compounds are analyzed in order to investigate how does the hydrophobic effect depend on molecular structure and shape. The contribution due to the hydrophobic effect is evaluated using a method we suggested previously. A number of values of the Gibbs free energies of solvation in dimethyl sulfoxide and in hexadecane, which are required for calculation, were determined by gas chromatographic headspace analysis. It is found that the Gibbs hydrophobic effect energy is linearly dependent on characteristic molecular volume for a large variety of solutes with branched and unbranched carbon chains, different functional groups and atomic composition. Molecular structure and shape do not significantly affect the hydrophobicity of chemical species, and molecular volume is a main factor determining it.

  17. Equilibrium structures and flows of polar and nonpolar liquids in different carbon nanotubes

    Science.gov (United States)

    Abramyan, Andrey K.; Bessonov, Nick M.; Mirantsev, Leonid V.; Chevrychkina, Anastasiia A.

    2018-03-01

    Molecular dynamics (MD) simulations of equilibrium structures and flows of polar water and nonpolar methane confined by single-walled carbon nanotubes (SWCNTs) with circular and square cross sections and bounding walls with regular graphene structure and random (amorphous) distribution of carbon atoms have been performed. The results of these simulations show that equilibrium structures of both confined liquids depend strongly on the shape of the cross section of SWCNTs, whereas the structure of their bounding walls has a minor influence on these structures. On contrary, the external pressure driven water and methane flows through above mentioned SWCNTs depend significantly on both the shape of their cross sections and the structure of their bounding walls.

  18. Tridodecylamine, an efficient charge control agent in non-polar media for electrophoretic inks application

    Science.gov (United States)

    Noel, Amélie; Mirbel, Déborah; Cloutet, Eric; Fleury, Guillaume; Schatz, Christophe; Navarro, Christophe; Hadziioannou, Georges; CyrilBrochon

    2018-01-01

    In order to obtain efficient electrophoretic inks, Tridodecylamine (Dod3N), has been studied as charge control agent (CCA) in a non-polar paraffin solvent (Isopar G) for various inorganic pigments (TiO2 and Fe2O3). All hydrophobic mineral oxides, i.e. treated with octyltrimethoxysilane (C8) or dodecyltrimethoxysilane (C12), were found to be negatively charged in presence of Dod3N. The electrophoretic mobilities of inorganic pigments seemed to be strongly dependent of their isoelectric point (IEP) and also of the concentration of dod3N with an optimum range between 10 and 20 mM depending on the pigments. Finally, an electrophoretic ink constituted of hydrophobic mineral oxides in presence of Dod3N was tested in a device. Its efficiency as charge control agent to negatively charge hydrophobic particles was confirmed through good optical properties and fast response time (220 ms at 200 kV m-1).

  19. Role of the electronegativity for the interface properties of non-polar heterostructures

    KAUST Repository

    Nazir, Safdar

    2012-04-01

    Density functional theory is used to investigate the interfaces in the non-polar ATiO 3/SrTiO 3 (A=Pb, Ca, Ba) heterostructures. All TiO 2-terminated interfaces show an insulating behavior. By reduction of the O content in the AO, SrO, and TiO 2 layers, metallic interface states develop, due to the occupation of the Ti 3d orbitals. For PbTiO 3/SrTiO 3, the Pb 6p states cross the Fermi energy. O vacancy formation energies depend strictly on the electronegativity and the effective volume of the A ion, while the main characteristics of the interface electronic states are maintained. © Europhysics Letters Association, 2012.

  20. Evaluation of Extraction Protocols for Simultaneous Polar and Non-Polar Yeast Metabolite Analysis Using Multivariate Projection Methods

    Directory of Open Access Journals (Sweden)

    Nicolas P. Tambellini

    2013-07-01

    Full Text Available Metabolomic and lipidomic approaches aim to measure metabolites or lipids in the cell. Metabolite extraction is a key step in obtaining useful and reliable data for successful metabolite studies. Significant efforts have been made to identify the optimal extraction protocol for various platforms and biological systems, for both polar and non-polar metabolites. Here we report an approach utilizing chemoinformatics for systematic comparison of protocols to extract both from a single sample of the model yeast organism Saccharomyces cerevisiae. Three chloroform/methanol/water partitioning based extraction protocols found in literature were evaluated for their effectiveness at reproducibly extracting both polar and non-polar metabolites. Fatty acid methyl esters and methoxyamine/trimethylsilyl derivatized aqueous compounds were analyzed by gas chromatography mass spectrometry to evaluate non-polar or polar metabolite analysis. The comparative breadth and amount of recovered metabolites was evaluated using multivariate projection methods. This approach identified an optimal protocol consisting of 64 identified polar metabolites from 105 ion hits and 12 fatty acids recovered, and will potentially attenuate the error and variation associated with combining metabolite profiles from different samples for untargeted analysis with both polar and non-polar analytes. It also confirmed the value of using multivariate projection methods to compare established extraction protocols.

  1. Technetium-99m labelled N,N-ethyldithiocarbamate, a non-polar complex with slow hepatic clearance

    International Nuclear Information System (INIS)

    Pojer, P.M.; Baldas, J.

    1980-05-01

    A sup(99m)Tc-N,N-diethyldithiocarbamate (DDC) complex was prepared using formamidine sulphinic acid as the reducing agent for pertechnetate sup(99m) Tc. The complex was found to be non-polar. In mice the complex localised in the liver and intestines. Urinary excretion was very low and hepatic clearance relatively slow

  2. Homogeneous solutions of hydrophilic enzymes in nonpolar organic solvents. New systems for fundamental studies and biocatalytic transformations.

    Science.gov (United States)

    Mozhaev, V V; Poltevsky, K G; Slepnev, V I; Badun, G A; Levashov, A V

    1991-11-04

    A typical hydrophilic enzyme, CT, can be dissolved in nonpolar organic solvents (n-octane, cyclohexane and toluene) up to microM concentrations. In the homogeneous solution obtained, the enzyme possesses catalytic activity and enormously high thermostability. It does not lose this activity even after several hours refluxing in octane (126 degrees C) or cyclohexane (81 degrees C).

  3. Creation of High Mobility Two-Dimensional Electron Gases via Strain Induced Polarization at an Otherwise Nonpolar Complex Oxide Interface

    DEFF Research Database (Denmark)

    Chen, Yunzhong; Trier, Felix; Kasama, Takeshi

    2015-01-01

    The discovery of two-dimensional electron gases (2DEGs) in SrTiO3-based heterostructures provides new opportunities for nanoelectronics. Herein, we create a new type of oxide 2DEG by the epitaxial-strain-induced polarization at an otherwise nonpolar perovskite-type interface of CaZrO3/SrTiO3. Rem...

  4. Origins of protein denatured state compactness and hydrophobic clustering in aqueous urea: inferences from nonpolar potentials of mean force.

    Science.gov (United States)

    Shimizu, Seishi; Chan, Hue Sun

    2002-12-01

    Free energies of pairwise hydrophobic association are simulated in aqueous solutions of urea at concentrations ranging from 0-8 M. Consistent with the expectation that hydrophobic interactions are weakened by urea, the association of relatively large nonpolar solutes is destabilized by urea. However, the association of two small methane-sized nonpolar solutes in water has the opposite tendency of being slightly strengthened by the addition of urea. Such size effects and the dependence of urea-induced stability changes on the configuration of nonpolar solutes are not predicted by solvent accessible surface area approaches based on energetic parameters derived from bulk-phase solubilities of model compounds. Thus, to understand hydrophobic interactions in proteins, it is not sufficient to rely solely on transfer experiment data that effectively characterize a single nonpolar solute in an aqueous environment but not the solvent-mediated interactions among two or more nonpolar solutes. We find that the m-values for the rate of change of two-methane association free energy with respect to urea concentration is a dramatically nonmonotonic function of the spatial separation between the two methanes, with a distance-dependent profile similar to the corresponding two-methane heat capacity of association in pure water. Our results rationalize the persistence of residual hydrophobic contacts in some proteins at high urea concentrations and explain why the heat capacity signature (DeltaC(P)) of a compact denatured state can be similar to DeltaC(P) values calculated by assuming an open random-coil-like unfolded state. Copyright 2002 Wiley-Liss, Inc.

  5. An absorbing microwave micro-solid-phase extraction device used in non-polar solvent microwave-assisted extraction for the determination of organophosphorus pesticides.

    Science.gov (United States)

    Wang, Ziming; Zhao, Xin; Xu, Xu; Wu, Lijie; Su, Rui; Zhao, Yajing; Jiang, Chengfei; Zhang, Hanqi; Ma, Qiang; Lu, Chunmei; Dong, Deming

    2013-01-14

    A single-step extraction-cleanup method, including microwave-assisted extraction (MAE) and micro-solid-phase extraction (μ-SPE), was developed for the extraction of ten organophosphorus pesticides in vegetable and fruit samples. Without adding any polar solvent, only one kind of non-polar solvent (hexane) was used as extraction solvent in the whole extraction step. Absorbing microwave μ-SPE device, was prepared by packing activated carbon with microporous polypropylene membrane envelope, and used as not only the sorbent in μ-SPE, but also the microwave absorption medium. Some experimental parameters effecting on extraction efficiency was investigated and optimized. 1.0 g of sample, 8 mL of hexane and three absorbing microwave μ-SPE devices were added in the microwave extraction vessel, the extraction was carried out under 400 W irradiation power at 60°C for 10 min. The extracts obtained by MAE-μ-SPE were directly analyzed by GC-MS without any clean-up process. The recoveries were in the range of 93.5-104.6%, and the relative standard deviations were lower than 8.7%. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Preparation and Characterization of High Purity Anhydrous β-Lactose from α-Lactose Monohydrate at Mild Temperature

    Directory of Open Access Journals (Sweden)

    Ana L. López-Pablos

    2018-01-01

    Full Text Available Lactose is a disaccharide of importance in humans dietary, food products, and the pharmaceutical industry. From the existing isomeric forms, β-lactose is rarely found in nature. Thus, in this work, a simple methodology to obtain anhydrous β-lactose (βL from α-lactose monohydrate (αL·H2O is presented. The αL·H2O powder was dispersed into a basic alcoholic solution (72 hours, at controlled conditions of temperature (27, 29, 31, and 32°C, without stirring. The slurry was dried at room temperature and characterized. Fourier transform infrared spectroscopy showed the formation of βL for the samples prepared at 29 and 32°C. Raman spectroscopy confirmed this result and suggested the occurrence of crystalline βL. Rietveld refinement of the X-ray diffraction patterns was employed to identify and quantify the composition of the isomers. The samples prepared at 29 and 31°C showed the formation of pure βL, while those at 27 and 32°C showed the presence of αL·H2O and a mixture of the two isomers, respectively. The morphology of the powders was studied by scanning electron microscopy, observing the formation of irregular shape αL·H2O particles and axe-like βL particles. Clearly, with this methodology, it was possible to obtain pure, crystalline, and anhydrous βL at mild temperature.

  7. Mixed sodium nickel-manganese sulfates: Crystal structure relationships between hydrates and anhydrous salts

    Energy Technology Data Exchange (ETDEWEB)

    Marinova, Delyana M.; Zhecheva, Ekaterina N.; Kukeva, Rositsa R.; Markov, Pavel V. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Nihtianova, Diana D. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Stoyanova, Radostina K., E-mail: radstoy@svr.igic.bas.bg [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2017-06-15

    The present contribution provides new structural and spectroscopic data on the formation of solid solutions between hydrated and dehydrated sulfate salts of sodium-nickel and sodium-manganese in a whole concentration range: Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·yH{sub 2}O, 0≤ x≤1.0. Using powder XRD, electron paramagnetic resonance spectroscopy (EPR), IR and Raman spectroscopy it has been found that double sodium-nickel and sodium-manganese salts form solid solutions Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·4H{sub 2}O with a blödite-type of structure within a broad concentration range of 0≤x≤0.49, while the manganese rich compositions Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·2H{sub 2}O (0.97≤x≤1.0) crystallize in the kröhnkite-type of structure. The Ni-based blödites Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·4H{sub 2}O dehydrate between 140 and 260 °C into anhydrous salts Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}, 0≤ x≤0.44, with a structure where Ni{sub 1−x}Mn{sub x}O{sub 6} octahedra are bridged into pairs by edge- and corner sharing SO{sub 4}{sup 2−} groups. Both TEM and EPR methods show that the Ni{sup 2+} and Mn{sup 2+} ions are homogenously distributed over three crystallographic positions of the large monoclinic cell. The dehydration of the kröhnkite phase Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·2H{sub 2}O yields the alluaudite phase Na{sub 2+δ}Mn{sub 2-δ/2}(SO{sub 4}){sub 3}, where the Na-to-Mn ratio decreases and all Ni{sup 2+} dopants are released from the structure. The process of the dehydration is discussed in terms of structural aspects taking into account the distortion degree of the Ni,MnO{sub 6} and SO{sub 4} polyhedra. - Graphical abstract: Thermal dehydration of the blödite phase Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·4H{sub 2}O (0≤ x≤0.49) yields nickel-manganese sulfates Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2} (0≤ x≤0.44) with

  8. Sulfur Concentration at Sulfide Saturation in Anhydrous Silicate Melts at Crustal Conditions

    Science.gov (United States)

    Liu, Y.; Samaha, N.; Baker, D. R.

    2006-05-01

    The sulfur concentration in silicate melts at sulfide saturation (SCSS) was experimentally investigated in a temperature range from 1250°C to 1450°C and a pressure range from 500 MPa to 1 GPa in a piston-cylinder apparatus. The investigated melt compositions varied from rhyolitic to basaltic. All experiments were saturated with a FeS melt. Temperature was confirmed to have a positive effect on the SCSS and no measurable pressure effect was observed. Oxygen fugacity was controlled to be either near the carbon-carbon monoxide buffer or one log unit above the nickel-nickel oxide buffer, and found to positively affect the SCSS. A series of models were constructed to predict the SCSS as a function of temperature, pressure, melt composition, oxygen fugacity and sulfur fugacity of the system. The coefficients were obtained by the regression of experimental data from this study and from data in the literature. The best model found for the prediction of the SCSS is: ln S (ppm) = 996/T + 9.875 + 0.997 ln MFM + 0.1901 ln fO2 - 0.0722 (P/T) -0.115 ln f S2, where P is in bar, T is in K, and MFM is a compositional parameter describing the melt based upon cation mole fractions: MFM = [Na + K + 2 (Ca + Mg+ Fe2+)]/[Si × (Al + Fe3+)]. This model predicts the SCSS in anhydrous silicate melts from rhyolitic to basaltic compositions at crustal conditions from 1 bar to 1.25 GPa, temperatures from ~1200 to 1400 C, and oxygen fugacities between approximately two log units below the fayalite-quartz-magnetite buffer and one log unit above the nickel-nickel oxide buffer. For cases where the oxygen and sulfur fugacities can not be adequately estimated a simpler model also works acceptably: ln S (ppm) = -5328/T + 8.431 + 1.244 ln MFM - 0.01704(P/T) + ln aFeS, where aFeS is the activity of FeS in the sulfide melt and is well approximated by a value of 1. Additional experiments were performed on other basalts in a temperature range from 1250 C to 1450 C at 1 GPa to test the models. The model

  9. Breaking the polar-nonpolar division in solvation free energy prediction.

    Science.gov (United States)

    Wang, Bao; Wang, Chengzhang; Wu, Kedi; Wei, Guo-Wei

    2018-02-05

    Implicit solvent models divide solvation free energies into polar and nonpolar additive contributions, whereas polar and nonpolar interactions are inseparable and nonadditive. We present a feature functional theory (FFT) framework to break this ad hoc division. The essential ideas of FFT are as follows: (i) representability assumption: there exists a microscopic feature vector that can uniquely characterize and distinguish one molecule from another; (ii) feature-function relationship assumption: the macroscopic features, including solvation free energy, of a molecule is a functional of microscopic feature vectors; and (iii) similarity assumption: molecules with similar microscopic features have similar macroscopic properties, such as solvation free energies. Based on these assumptions, solvation free energy prediction is carried out in the following protocol. First, we construct a molecular microscopic feature vector that is efficient in characterizing the solvation process using quantum mechanics and Poisson-Boltzmann theory. Microscopic feature vectors are combined with macroscopic features, that is, physical observable, to form extended feature vectors. Additionally, we partition a solvation dataset into queries according to molecular compositions. Moreover, for each target molecule, we adopt a machine learning algorithm for its nearest neighbor search, based on the selected microscopic feature vectors. Finally, from the extended feature vectors of obtained nearest neighbors, we construct a functional of solvation free energy, which is employed to predict the solvation free energy of the target molecule. The proposed FFT model has been extensively validated via a large dataset of 668 molecules. The leave-one-out test gives an optimal root-mean-square error (RMSE) of 1.05 kcal/mol. FFT predictions of SAMPL0, SAMPL1, SAMPL2, SAMPL3, and SAMPL4 challenge sets deliver the RMSEs of 0.61, 1.86, 1.64, 0.86, and 1.14 kcal/mol, respectively. Using a test set of 94

  10. Heme and non-heme iron transporters in non-polarized and polarized cells

    Directory of Open Access Journals (Sweden)

    Yasui Yumiko

    2010-06-01

    Full Text Available Abstract Background Heme and non-heme iron from diet, and recycled iron from hemoglobin are important products of the synthesis of iron-containing molecules. In excess, iron is potentially toxic because it can produce reactive oxygen species through the Fenton reaction. Humans can absorb, transport, store, and recycle iron without an excretory system to remove excess iron. Two candidate heme transporters and two iron transporters have been reported thus far. Heme incorporated into cells is degraded by heme oxygenases (HOs, and the iron product is reutilized by the body. To specify the processes of heme uptake and degradation, and the reutilization of iron, we determined the subcellular localizations of these transporters and HOs. Results In this study, we analyzed the subcellular localizations of 2 isoenzymes of HOs, 4 isoforms of divalent metal transporter 1 (DMT1, and 2 candidate heme transporters--heme carrier protein 1 (HCP1 and heme responsive gene-1 (HRG-1--in non-polarized and polarized cells. In non-polarized cells, HCP1, HRG-1, and DMT1A-I are located in the plasma membrane. In polarized cells, they show distinct localizations: HCP1 and DMT1A-I are located in the apical membrane, whereas HRG-1 is located in the basolateral membrane and lysosome. 16Leu at DMT1A-I N-terminal cytosolic domain was found to be crucial for plasma membrane localization. HOs are located in smooth endoplasmic reticulum and colocalize with NADPH-cytochrome P450 reductase. Conclusions HCP1 and DMT1A-I are localized to the apical membrane, and HRG-1 to the basolateral membrane and lysosome. These findings suggest that HCP1 and DMT1A-I have functions in the uptake of dietary heme and non-heme iron. HRG-1 can transport endocytosed heme from the lysosome into the cytosol. These localization studies support a model in which cytosolic heme can be degraded by HOs, and the resulting iron is exported into tissue fluids via the iron transporter ferroportin 1, which is

  11. Homoepitaxial nonpolar (10-10) ZnO/ZnMgO monolithic microcavities: Towards reduced photonic disorder

    International Nuclear Information System (INIS)

    Zuniga-Perez, J.; Kappei, L.; Deparis, C.; Chenot, S.; Leroux, M.; Reveret, F.; Jamadi, O.; Leymarie, J.; Grundmann, M.; Prado, E. de

    2016-01-01

    Nonpolar ZnO/ZnMgO-based optical microcavities have been grown on (10-10) m-plane ZnO substrates by plasma-assisted molecular beam epitaxy. Reflectivity measurements indicate an exponential increase of the cavity quality factor with the number of layers in the distributed Bragg reflectors. Most importantly, microreflectivity spectra recorded with a spot size in the order of 2 μm show a negligible photonic disorder (well below 1 meV), leading to local quality factors equivalent to those obtained by macroreflectivity. The anisotropic character of the nonpolar heterostructures manifests itself both in the surface features, elongated parallel to the in-plane c direction, and in the optical spectra, with two cavity modes being observed at different energies for orthogonal polarizations.

  12. Homoepitaxial nonpolar (10-10) ZnO/ZnMgO monolithic microcavities: Towards reduced photonic disorder

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga-Perez, J., E-mail: jzp@crhea.cnrs.fr; Kappei, L.; Deparis, C.; Chenot, S.; Leroux, M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Reveret, F.; Jamadi, O.; Leymarie, J. [Clermont Université, Institut Pascal (IP), BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6602, IP, F-63171 Aubière (France); Grundmann, M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Institut für Experimentelle Physik II, Fakultät für Physik und Geowissenschaften, Universität Leipzig, Linnestr. 5, 04103 Leipzig (Germany); Prado, E. de [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Departamento de Física Aplicada y Electromagnetismo, Universitat de Valencia, c/Dr Moliner 50, Burjassot, Valencia 46100 (Spain)

    2016-06-20

    Nonpolar ZnO/ZnMgO-based optical microcavities have been grown on (10-10) m-plane ZnO substrates by plasma-assisted molecular beam epitaxy. Reflectivity measurements indicate an exponential increase of the cavity quality factor with the number of layers in the distributed Bragg reflectors. Most importantly, microreflectivity spectra recorded with a spot size in the order of 2 μm show a negligible photonic disorder (well below 1 meV), leading to local quality factors equivalent to those obtained by macroreflectivity. The anisotropic character of the nonpolar heterostructures manifests itself both in the surface features, elongated parallel to the in-plane c direction, and in the optical spectra, with two cavity modes being observed at different energies for orthogonal polarizations.

  13. Surface topology caused by dislocations in polar, semipolar, and nonpolar InGaN/GaN heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Schade, L.; Schwarz, U.T. [Fraunhofer Institute for Applied Solid State Physics IAF, Freiburg (Germany); Department of Microsystems Engineering (IMTEK), University of Freiburg (Germany); Wernicke, T.; Rass, J.; Ploch, S. [Institute of Solid State Physics, TU Berlin (Germany); Weyers, M. [Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Berlin (Germany); Kneissl, M. [Institute of Solid State Physics, TU Berlin (Germany); Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Berlin (Germany)

    2014-04-15

    The impact of dislocations on surface topology as well as on quantum well emission in c-plane, semipolar, and nonpolar InGaN/GaN heterostructures is being analyzed by micro-photoluminescence and white-light-interferometry. V-pits with (10 anti 11) and (10 anti 1 anti 4) side facets are identified in a (10 anti 12) semipolar heterostructure. Hillocks formed by spiral growth around screw dislocations change from hexagonal to triangular to rectangular shape in polar, semipolar, and nonpolar heterostructures, respectively, reflecting the symmetry of the individual surface. The emission in semipolar quantum wells, grown homoepitaxially on bulk GaN substrates, show dark stripes aligned with misfit dislocations. For (11 anti 22) and (20 anti 21) orientation, these dark stripes are perpendicular and parallel, respectively, to surface striation. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Comparative studies of efficiency droop in polar and non-polar InGaN quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Davies, M. J.; Dawson, P.; Hammersley, S. [School of Physics and Astronomy, Photon Science Institute, University of Manchester, M13 9PL Manchester (United Kingdom); Zhu, T.; Kappers, M. J.; Humphreys, C. J.; Oliver, R. A. [Department of Material Science and Metallurgy, 27 Charles Babbage Road, University of Cambridge, Cambridge CB3 0FS (United Kingdom)

    2016-06-20

    We report on a comparative study of efficiency droop in polar and non-polar InGaN quantum well structures at T = 10 K. To ensure that the experiments were carried out with identical carrier densities for any particular excitation power density, we used laser pulses of duration ∼100 fs at a repetition rate of 400 kHz. For both types of structures, efficiency droop was observed to occur for carrier densities of above 7 × 10{sup 11 }cm{sup −2 }pulse{sup −1} per quantum well; also both structures exhibited similar spectral broadening in the droop regime. These results show that efficiency droop is intrinsic in InGaN quantum wells, whether polar or non-polar, and is a function, specifically, of carrier density.

  15. Comparative studies of efficiency droop in polar and non-polar InGaN quantum wells

    International Nuclear Information System (INIS)

    Davies, M. J.; Dawson, P.; Hammersley, S.; Zhu, T.; Kappers, M. J.; Humphreys, C. J.; Oliver, R. A.

    2016-01-01

    We report on a comparative study of efficiency droop in polar and non-polar InGaN quantum well structures at T = 10 K. To ensure that the experiments were carried out with identical carrier densities for any particular excitation power density, we used laser pulses of duration ∼100 fs at a repetition rate of 400 kHz. For both types of structures, efficiency droop was observed to occur for carrier densities of above 7 × 10 11  cm −2  pulse −1 per quantum well; also both structures exhibited similar spectral broadening in the droop regime. These results show that efficiency droop is intrinsic in InGaN quantum wells, whether polar or non-polar, and is a function, specifically, of carrier density.

  16. Piezoelectricity and rotostriction through polar and non-polar coupled instabilities in bismuth-based piezoceramics.

    Science.gov (United States)

    Acosta, Matias; Schmitt, Ljubomira A; Cazorla, Claudio; Studer, Andrew; Zintler, Alexander; Glaum, Julia; Kleebe, Hans-Joachim; Donner, Wolfgang; Hoffman, Mark; Rödel, Jürgen; Hinterstein, Manuel

    2016-07-01

    Coupling of order parameters provides a means to tune functionality in advanced materials including multiferroics, superconductors, and ionic conductors. We demonstrate that the response of a frustrated ferroelectric state leads to coupling between order parameters under electric field depending on grain orientation. The strain of grains oriented along a specific crystallographic direction, 〈h00〉, is caused by converse piezoelectricity originating from a ferrodistortive tetragonal phase. For 〈hhh〉 oriented grains, the strain results from converse piezoelectricity and rotostriction, as indicated by an antiferrodistortive instability that promotes octahedral tilting in a rhombohedral phase. Both strain mechanisms combined lead to a colossal local strain of (2.4 ± 0.1) % and indicate coupling between oxygen octahedral tilting and polarization, here termed "rotopolarization". These findings were confirmed with electromechanical experiments, in situ neutron diffraction, and in situ transmission electron microscopy in 0.75Bi1/2Na1/2TiO3-0.25SrTiO3. This work demonstrates that polar and non-polar instabilities can cooperate to provide colossal functional responses.

  17. Defects of polar, semipolar and nonpolar (In)GaN - a comparison

    Energy Technology Data Exchange (ETDEWEB)

    Schade, Lukas; Schwarz, Ulrich [Department of Microsystems Engeneering, IMTEK, University Freiburg (Germany); Fraunhofer Institute for Applied Solid State Physics (Germany); Wernicke, Tim; Rass, Jens; Ploch, Simon [Institute of Solid State Physics, Technical University Berlin (Germany); Forghani, Kamran [Institute for Optoelectronics, University Ulm (Germany); University of Wisconsin, Madison (United States); Kirste, Lutz [Fraunhofer Institute for Applied Solid State Physics (Germany); Weyers, Markus [Ferdinand-Braun-Institut, Berlin (Germany); Kneissl, Michael [Institute of Solid State Physics, Technical University Berlin (Germany); Ferdinand-Braun-Institut, Berlin (Germany); Scholz, Ferdinand [Institute for Optoelectronics, University Ulm (Germany)

    2013-07-01

    The GaN/InGaN material system is used to realize light emitting diodes from UV-A to the green-yellow spectral region. However, even on quasi bulk GaN substrates threading dislocations (TDs) are present with a density of 10{sup 7} cm{sup -2}. Here, we examine the influence of TDs on the luminescence intensity and transition energy. The impact caused by nonradiative recombination centers and strain fields is analyzed by micro photoluminescence and white light interferometry. We compare TDs in differently oriented GaN layers and InGaN QWs. Three types of burgers vectors are typically observed in GaN: a, c and a+c. When the surface orientation is changed from (0001) c-plane to (10 anti 10) m-plane, their character changes from edge to screw type and vice versa. We studied TDs and V-defects associated to them in polar, semipolar and nonpolar GaN and InGaN QWs. Additionally, we will present the effect of Si doping onto the strain field in (0001) GaN edge dislocations. In undoped GaN, the strain around such a dislocation forms a symmetric dipole. With Si doping, the strain dipole becomes asymmetric.

  18. Nanoporous distributed Bragg reflectors on free-standing nonpolar m-plane GaN

    Science.gov (United States)

    Mishkat-Ul-Masabih, Saadat; Luk, Ting Shan; Rishinaramangalam, Ashwin; Monavarian, Morteza; Nami, Mohsen; Feezell, Daniel

    2018-01-01

    We report the fabrication of m-plane nanoporous distributed Bragg reflectors (DBRs) on free-standing GaN substrates. The DBRs consist of 15 pairs of alternating undoped and highly doped n-type ([Si] = ˜3.7 × 1019 cm-3) GaN. Electrochemical (EC) etching was performed to convert the highly doped regions into a porous material, consequently reducing the effective refractive index of the layers. We demonstrate a DBR with peak reflectance greater than 98% at 450 nm with a stopband width of ˜72 nm. The polarization ratio of an incident polarized light source remains identical after reflection from the DBR, verifying that there is no drop in the polarization ratio due to the interfaces between the porous layers. We also quantify the porosity under various EC bias conditions for layers with different doping concentrations. The bias voltage controls the average pore diameter, while the pore density is primarily determined by the doping concentration. The results show that nanoporous DBRs on nonpolar free-standing GaN are promising candidates for high-reflectance, lattice-matched DBR mirrors for GaN-based resonant cavity devices.

  19. Thin film epitaxy and structure property correlations for non-polar ZnO films

    International Nuclear Information System (INIS)

    Pant, P.; Budai, J.D.; Aggarwal, R.; Narayan, Roger J.; Narayan, J.

    2009-01-01

    Heteroepitaxial growth and strain relaxation were investigated in non-polar a-plane (1 1 -2 0)ZnO films grown on r-plane (1 0 -1 2)sapphire substrates in the temperature range 200-700 deg. C by pulsed laser deposition. The lattice misfit in the plane of the film for this orientation varied from -1.26% in [0 0 0 1] to -18.52% in the [-1 1 0 0] direction. The alignment of (1 1 -2 0)ZnO planes parallel to (1 0 -1 2)sapphire planes was confirmed by X-ray diffraction θ-2θ scans over the entire temperature range. X-ray φ-scans revealed the epitaxial relationship:[0 0 0 1]ZnO-parallel [-1 1 0 1]sap; [-1 1 0 0]ZnO-parallel [-1 -1 2 0]sap. Depending on the growth temperature, variations in the structural, optical and electrical properties were observed in the grown films. Room temperature photoluminescence for films grown at 700 deg. C shows a strong band-edge emission. The ratio of the band-edge emission to green band emission is 135:1, indicating reduced defects and excellent optical quality of the films. The resistivity data for the films grown at 700 deg. C shows semiconducting behavior with room temperature resistivity of 2.2 x 10 -3 Ω-cm.

  20. On the spallation of a polarized photon on a nonpolarized electron

    International Nuclear Information System (INIS)

    Bozrikov, P.V.; Kopytov, G.F.

    1978-01-01

    Considered is the process of the spallation of a polarized photon of the plane electromagnet wave into two polarized photons on a nonpolarized electron. One of these photons is considered as an emitted one, another as a photon of a plane wave. The degrees of circular and linear polarization of the emitted photon are studied in detail. It is shown that the degree of linear polarization does not depend on the type of circular polarization of the initial plane wave photon. At a relativistic electron moving in the direction of the plane wave, totally linearly polarized radiation appears. The analogy between the following two processes is made: (1) γ 1 +e - → γ 2 + γ tilde +e' - (where γ 1 , γ 2 are photons of the plane wave, and γ tilde is an emitted photon) and (2) γ 1 +e - → γ 2 +γ 3 +e' - . From the correspondence between the processes it follows that the results of the investigation may be applied to the double Compton effect. Besides, it appears to be possible to study the correlation between polarization states of all three photons participating in the double Compton scattering

  1. A Fast Chromatographic Method for Estimating Lipophilicity and Ionization in Nonpolar Membrane-Like Environment.

    Science.gov (United States)

    Caron, Giulia; Vallaro, Maura; Ermondi, Giuseppe; Goetz, Gilles H; Abramov, Yuriy A; Philippe, Laurence; Shalaeva, Marina

    2016-03-07

    This study describes the design and implementation of a new chromatographic descriptor called log k'80 PLRP-S that provides information about the lipophilicity of drug molecules in the nonpolar environment, both in their neutral and ionized form. The log k'80 PLRP-S obtained on a polymeric column with acetonitrile/water mobile phase is shown to closely relate to log Ptoluene (toluene dielectric constant ε ∼ 2). The main intermolecular interactions governing log k'80 PLRP-S were deconvoluted using the Block Relevance (BR) analysis. The information provided by this descriptor was compared to ElogD and calclog Ptol, and the differences are highlighted. The "charge-flush" concept is introduced to describe the sensitivity of log k'80 PLRP-S to the ionization state of compounds in the pH range 2 to 12. The ability of log k'80 PLRP-S to indicate the propensity of neutral molecules and monoanions to form Intramolecular Hydrogen Bonds (IMHBs) is proven through a number of examples.

  2. Nanospikes functionalization as a universal strategy to disperse hydrophilic particles in non-polar media

    Science.gov (United States)

    Hang, Tian; Chen, Hui-Jiuan; Wang, Ji; Lin, Di-an; Wu, Jiangming; Liu, Di; Cao, Yuhong; Yang, Chengduan; Liu, Chenglin; Xiao, Shuai; Gu, Meilin; Pan, Shuolin; Wu, Mei X.; Xie, Xi

    2018-05-01

    Dispersion of hydrophilic particles in non-polar media has many important applications yet remains difficult. Surfactant or amphiphilic functionalization was conventionally applied to disperse particles but is highly dependent on the particle/solvent system and may induce unfavorable effects and impact particle hydrophilic nature. Recently 2 μm size polystyrene microbeads coated with ZnO nanospikes have been reported to display anomalous dispersity in phobic media without using surfactant or amphiphilic functionalization. However, due to the lack of understanding whether this phenomenon was applicable to a wider range of conditions, little application has been derived from it. Here the anomalous dispersity phenomenons of hydrophilic microparticles covered with nanospikes were systematically assessed at various conditions including different particle sizes, material compositions, particle morphologies, solvent hydrophobicities, and surface polar groups. Microparticles were functionalized with nanospikes through hydrothermal route, followed by dispersity test in hydrophobic media. The results suggest nanospikes consistently prevent particle aggregation in various particle or solvent conditions, indicating the universal applicability of the anomalous dispersion phenomenons. This work provides insight on the anomalous dispersity of hydrophilic particles in various systems and offers potential application to use this method for surfactant-free dispersions.

  3. Single charging events on colloidal particles in a nonpolar liquid with surfactant

    Science.gov (United States)

    Schreuer, Caspar; Vandewiele, Stijn; Brans, Toon; Strubbe, Filip; Neyts, Kristiaan; Beunis, Filip

    2018-01-01

    Electrical charging of colloidal particles in nonpolar liquids due to surfactant additives is investigated intensively, motivated by its importance in a variety of applications. Most methods rely on average electrophoretic mobility measurements of many particles, which provide only indirect information on the charging mechanism. In the present work, we present a method that allows us to obtain direct information on the charging mechanism, by measuring the charge fluctuations on individual particles with a precision higher than the elementary charge using optical trapping electrophoresis. We demonstrate the capabilities of the method by studying the influence of added surfactant OLOA 11000 on the charging of single colloidal PMMA particles in dodecane. The particle charge and the frequency of charging events are investigated both below and above the critical micelle concentration (CMC) and with or without applying a DC offset voltage. It is found that at least two separate charging mechanisms are present below the critical micelle concentration. One mechanism is a process where the particle is stripped from negatively charged ionic molecules. An increase in the charging frequency with increased surfactant concentration suggests a second mechanism that involves single surfactant molecules. Above the CMC, neutral inverse micelles can also be involved in the charging process.

  4. Structural investigation of diglycerol monolaurate reverse micelles in nonpolar oils cyclohexane and octane

    International Nuclear Information System (INIS)

    Shrestha, Lok Kumar; Aramaki, Kenji

    2009-01-01

    Structure of diglycerol monolaurate (abbreviated as C 12 G 2 ) micelles in nonpolar oils cyclohexane and n-octane as a function of compositions, temperatures, and surfactant chain length has been investigated by small-angle X-ray scattering (SAXS). The SAXS data were evaluated by the generalized indirect Fourier transformation (GIFT) method and real-space structural information of particles was achieved. Conventional poly(oxyethylene) type nonionic surfactants do not form reverse micelles in oils unless a trace water is added. However, present surfactant C 12 G 2 formed reverse micelle (RM) in cyclohexane and n-octane without addition of water at normal room temperature. A clear signature of one dimensional (1-D) micellar growth was found with increasing C 12 G 2 concentration. On the other hand, increasing temperature or hydrocarbon chain length of surfactant shorten the length of RM, which is essentially a cylinder-to-sphere type transition in the aggregate structure. Drastic changes in the structure of RM, namely, transition of ellipsoidal prolate to long rod-like micelles was observed upon changing oil from cyclohexane to octane. All the microstructural transitions were explained in terms of critical packing parameter. (author)

  5. Composition of the non-polar extracts and antimicrobial activity of Chorisia insignis HBK. leaves

    Directory of Open Access Journals (Sweden)

    Salma Ahmed Mahmoud El Sawi

    2014-12-01

    Full Text Available Objective: To investigate the chemical constituents of the petroleum ether extract and the ether fraction of the 70% ethanol extract of Chorisia insignis HBK. leaves, as well as screen its antimicrobial activity. Methods: Different chromatographic methods were applied to investigate the non-polar extracts and the diffusion assay method was applied to study the antimicrobial activity. Results: A total of 50 compounds from the unsaponifiable matter and 20 fatty acid methyl esters were identified from the petroleum ether extract by GC/MS analysis. n-Hentriacontane, n-tritriacontane, stigmastanol, 3-methoxy-5, 6-dihydrostigmasterol, 7,8-dihydroergosterol, 4-methylcholesterol, cholestanol, multiflorenol, cholest-5-en-3-one, cholest-6-one, 5,6- dihydroergosterol, stigmasterol, dihydroalbigenin and 11-methyl-Δ5,7,9,15,17,23-triacont-hex-ene were isolated from the petroleum ether extract. Methyl heptacosanoate and quinic acid ester of rhamnose were isolated from the ether fraction of the 70% ethanol extract. Antimicrobial activity of the total alcohol extract and the successive fractions showed that the ether and the ethyl acetate fractions have potent antibacterial activity against Bacillus subtilis and Bacillus cereus. Conclusions: The ether and the ethyl acetate fractions could be used in pharmaceutical formulations as antibacterial agents against Bacillus subtilis and Bacillus cereus, and further clinical trials should be performed in order to support the above investigations.

  6. Synthesis of N-methyl and N-11C-methyl spiperone by phase transfer catalysis in anhydrous solvent

    International Nuclear Information System (INIS)

    Omokawa, Hiroyoshi; Tanaka, Akira; Iio, Mayumi; Nishihara, Yoshiaki; Inoue, Osamu; Yamazaki, Toshio.

    1985-01-01

    Spiperone, a butyrophenone neuroleptic drug, has been used in binding studies of dopamine receptors. Langstrom et al. developed N- 11 C-methyl spiperone, and, in cooperate with Wagner et al., made it possible to visualize the distribution of dopamine receptors in the human brain in vivo. In this paper, we independently developed another synthetic method of N- 11 C-methyl spiperone using the phase transfer catalyst in an anhydrous solvent. Separation of the product is feasible only by passing the reactant solution through a Millipore filter and injecting it onto high pressure liquid chromatography (HPLC). The time required for the synthesis and purification of N- 11 C-methyl spiperone from 11 C-methyl iodide and spiperone was 20 min. Radiochemical yield exceeded 35 % against 11 C-methyl iodide without correcting decay of the radioactivity. (author)

  7. Automatic synthesis of [11C]NKY-722 with high specific activity, using anhydrous [11C] methanol as a precursor

    International Nuclear Information System (INIS)

    Suzuki, Kazutoshi; Inoue, Osamu; Itoh, Takashi; Nemoto, Kazuyoshi; Oosumi, Seimei; Miwa, Soichi.

    1992-01-01

    3-(4-allyl-1-piperazinyl)-2,2-dimethylpropyl methyl 1,4-dihydro-2,6-dimethyl- 4-(3-nitrophenyl)-3,5-pyridine dicarboxylate (NKY-722) was labeled with carbon-11 using anhydrous [ 11 C] methanol. Using a computer controlled equipment, a few GBq of [ 11 C] NKY-722 with the specific activity of 120 - 180 GBq/μmol could by synthesized at the radiochemical purity of > 99% in 10 ml of physiological saline containing Polysolvate-80 (1.5 vol%) and ethyl alcohol (0.75 vol%). Preliminary PET experiments using rats and a rhesus monkey have bee done, and very low accumulation of the compound into the brain, however comparatively higher accumulation in the heart were observed. (author)

  8. Preparation of a novel bioavailable curcuminoid formulation (Cureit™) using Polar-Nonpolar-Sandwich (PNS) technology and its characterization and applications

    International Nuclear Information System (INIS)

    Amalraj, Augustine; Jude, Shintu; Varma, Karthik; Jacob, Joby; Gopi, Sreeraj; Oluwafemi, Oluwatobi S.; Thomas, Sabu

    2017-01-01

    Health benefits of curcuminoid are highly limited due to their poor aqueous solubility, very low systemic bioavailability, fast metabolic alterations and rapid elimination. In this study, a novel bioavailable curcuminoid formulation Cureit™ was prepared by using Polar-Nonpolar-Sandwich (PNS) technology with complete natural turmeric matrix (CNTM). The synthesized bioavailable curcuminoid formulation Cureit™ was characterizations by Nuclear magnetic resonance spectroscopy (NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infra-red (IR), current-voltage (I-V) study, Quadrupole Time-of-Flight Mass Spectrometry (Q-TOF), differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). NMR study showed the presence of hydrogen bonding interactions with curcuminoids, polar and non-polar compounds in the PNS technology. SEM images indicated that Cureit™ was almost spherical and well dispersed with rough morphology, and separated with three layers of PNS formulation. The chemical profile of Cureit™ was analyzed by Q-TOF confirmed the presence of curcuminoids (curcumin, demethoxycurcumin and bismethoxycurcumin), lactones, sesquiterpenes and their derivatives derived from polar layer, aromatic turmerone, dihydroturmerone, turmeronol, curdione and bisacurone derived from non-polar layer. IR, XRD, DSC and TGA also confirmed the presence of curcuminoids with high stability in the PNS formulation. Various biological activities of Cureit™ were also discussed. - Highlights: • A novel bioavailable curcuminoid formulation Cureit™ was prepared. • Polar-Nonpolar-Sandwich technology is used with complete natural turmeric matrix. • Cureit™ was analyzed and predicted by NMR, SEM, XRD, IR, I-V, Q-TOF, DSC and TGA. • Cureit™ exhibited 10 fold higher bioavailable curcuminoid than pure curcuminoid.

  9. Direct Evidence of Mg Incorporation Pathway in Vapor-Liquid-Solid Grown p-type Nonpolar GaN Nanowires

    OpenAIRE

    Patsha, Avinash; Amirthapandian, S.; Pandian, Ramanathaswamy; Bera, S.; Bhattacharya, Anirban; Dhara, Sandip

    2015-01-01

    Doping of III-nitride based compound semiconductor nanowires is still a challenging issue to have a control over the dopant distribution in precise locations of the nanowire optoelectronic devices. Knowledge of the dopant incorporation and its pathways in nanowires for such devices is limited by the growth methods. We report the direct evidence of incorporation pathway for Mg dopants in p-type nonpolar GaN nanowires grown via vapour-liquid-solid (VLS) method in a chemical vapour deposition te...

  10. Preparation of a novel bioavailable curcuminoid formulation (Cureit™) using Polar-Nonpolar-Sandwich (PNS) technology and its characterization and applications

    Energy Technology Data Exchange (ETDEWEB)

    Amalraj, Augustine; Jude, Shintu; Varma, Karthik; Jacob, Joby [R& D Centre, Aurea Biolabs (P) Ltd, Kolenchery, Cochin, 682 311, Kerala (India); Gopi, Sreeraj, E-mail: sreeraj.gopi@plantlipids.com [R& D Centre, Aurea Biolabs (P) Ltd, Kolenchery, Cochin, 682 311, Kerala (India); Oluwafemi, Oluwatobi S. [Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, P.O. Box 17011, Doornfontein, 2028 Johannesburg (South Africa); Centre for Nanomaterials Science Research, University of Johannesburg, Johannesburg (South Africa); Thomas, Sabu [School of Chemical Sciences, Mahatma Gandhi University, Kottayam (India)

    2017-06-01

    Health benefits of curcuminoid are highly limited due to their poor aqueous solubility, very low systemic bioavailability, fast metabolic alterations and rapid elimination. In this study, a novel bioavailable curcuminoid formulation Cureit™ was prepared by using Polar-Nonpolar-Sandwich (PNS) technology with complete natural turmeric matrix (CNTM). The synthesized bioavailable curcuminoid formulation Cureit™ was characterizations by Nuclear magnetic resonance spectroscopy (NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infra-red (IR), current-voltage (I-V) study, Quadrupole Time-of-Flight Mass Spectrometry (Q-TOF), differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). NMR study showed the presence of hydrogen bonding interactions with curcuminoids, polar and non-polar compounds in the PNS technology. SEM images indicated that Cureit™ was almost spherical and well dispersed with rough morphology, and separated with three layers of PNS formulation. The chemical profile of Cureit™ was analyzed by Q-TOF confirmed the presence of curcuminoids (curcumin, demethoxycurcumin and bismethoxycurcumin), lactones, sesquiterpenes and their derivatives derived from polar layer, aromatic turmerone, dihydroturmerone, turmeronol, curdione and bisacurone derived from non-polar layer. IR, XRD, DSC and TGA also confirmed the presence of curcuminoids with high stability in the PNS formulation. Various biological activities of Cureit™ were also discussed. - Highlights: • A novel bioavailable curcuminoid formulation Cureit™ was prepared. • Polar-Nonpolar-Sandwich technology is used with complete natural turmeric matrix. • Cureit™ was analyzed and predicted by NMR, SEM, XRD, IR, I-V, Q-TOF, DSC and TGA. • Cureit™ exhibited 10 fold higher bioavailable curcuminoid than pure curcuminoid.

  11. Recent Advances in Anhydrous Solvents for CO{sub 2} Capture: Ionic Liquids, Switchable Solvents, and Nanoparticle Organic Hybrid Materials

    Energy Technology Data Exchange (ETDEWEB)

    Park, Youngjune [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju (Korea, Republic of); Lin, Kun-Yi Andrew [Department of Environmental Engineering, National Chung Hsing University, Taichung City (China); Park, Ah-Hyung Alissa, E-mail: ap2622@columbia.edu [Department of Earth and Environmental Engineering, Lenfest Center for Sustainable Energy, Columbia University, New York, NY (United States); Department of Chemical Engineering, Lenfest Center for Sustainable Energy, Columbia University, New York, NY (United States); Petit, Camille, E-mail: ap2622@columbia.edu [Department of Chemical Engineering, Imperial College London, London (United Kingdom)

    2015-10-01

    CO{sub 2} capture by amine scrubbing, which has a high CO{sub 2} capture capacity and a rapid reaction rate, is the most employed and investigated approach to date. There are a number of recent large-scale demonstrations including the Boundary Dam Carbon Capture Project by SaskPower in Canada that have reported successful implementations of aqueous amine solvent in CO{sub 2} capture from flue gases. The findings from these demonstrations will significantly advance the field of CO{sub 2} capture in the coming years. While the latest efforts in aqueous amine solvents are exciting and promising, there are still several drawbacks to amine-based CO{sub 2} capture solvents including high volatility and corrosiveness of the amine solutions as well as the high parasitic energy penalty during the solvent regeneration step. Thus, in a parallel effort, alternative CO{sub 2} capture solvents, which are often anhydrous, have been developed as the third-generation CO{sub 2} capture solvents. These novel classes of liquid materials include ionic liquids, CO{sub 2}-triggered switchable solvents (i.e., CO{sub 2}-binding organic liquids, reversible ionic liquids), and nanoparticle organic hybrid materials. This paper provides a review of these various anhydrous solvents and their potential for CO{sub 2} capture. Particular attention is given to the mechanisms of CO{sub 2} absorption in these solvents, their regeneration and their processability – especially taking into account their viscosity. While not intended to provide a complete coverage of the existing literature, this review aims at pointing the major findings reported for these new classes of CO{sub 2} capture media.

  12. Crystalline anhydrous {alpha},{alpha}-trehalose (polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose: A calorimetric study

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Susana S. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: susanapinto@ist.utl.pt; Diogo, Herminio P. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: hdiogo@ist.utl.pt; Moura-Ramos, Joaquim J. [Centro de Quimica-Fisica Molecular, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: mouraramos@ist.utl.pt

    2006-09-15

    The mean values of the standard massic energy of combustion of crystalline anhydrous {alpha},{alpha}-trehalose (C{sub 12}H{sub 22}O{sub 11}, polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose (C{sub 12}H{sub 26}O{sub 13}) measured by static-bomb combustion calorimetry in oxygen, at the temperature T=298.15K, are {delta}{sub c}u{sup o}=-(16434.05+/-4.50)J.g{sup -1} and {delta}{sub c}u{sup o}=-(14816.05+/-3.52)J.g{sup -1}, respectively. The standard (p{sup o}=0.1MPa) molar enthalpy of formation of these compounds were derived from the corresponding standard molar enthalpies of combustion, respectively, {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 22}O{sub 11},cr)=-(2240.9+/-3.9)kJ.mol{sup -1}, and {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 26}O{sub 13},cr)=-(2832.6+/-3.6)kJ.mol{sup -1}. The values of the standard enthalpies of formation obtained in this work, together with data on enthalpies of solution at infinite dilution ({delta}{sub sol}H{sup {approx}}) for crystalline dihydrate and amorphous anhydrous trehalose, allow a better insight on the thermodynamic description of the trehalose system which can provide, together with the future research on the subject, a contribution for understanding the metabolism in several organisms, as well as the phase transition between the different polymorphs.

  13. Recent Advances in Anhydrous Solvents for CO2 Capture: Ionic Liquids, Switchable Solvents, and Nanoparticle Organic Hybrid Materials

    Directory of Open Access Journals (Sweden)

    YOUNGJUNE ePARK

    2015-10-01

    Full Text Available CO2 capture by amine scrubbing, which has a high CO2 capture capacity and a rapid reaction rate, is the most employed and investigated approach to date. There are a number of recent large-scale demonstrations including the Boundary Dam Carbon Capture Project by SaskPower in Canada that have reported successful implementations of aqueous amine solvent in CO2 capture from flue gases. The findings from these demonstrations will significantly advance the field of CO2 capture in the coming years. While the latest efforts in aqueous amine solvents are exciting and promising, there are still several drawbacks to amine-based CO2 capture solvents including high volatility and corrosiveness of the amine solutions, as well as the high parasitic energy penalty during the solvent regeneration step. Thus, in a parallel effort, alternative CO2 capture solvents, which are often anhydrous, have been developed as the third-generation CO2 capture solvents. These novel classes of liquid materials include: Ionic Liquids (ILs, CO2-triggered switchable solvents (i.e., CO2 Binding Organic Liquids (CO2BOLs, Reversible Ionic Liquids (RevILs, and Nanoparticle Organic Hybrid Materials (NOHMs. This paper provides a review of these various anhydrous solvents and their potential for CO2 capture. Particular attention is given to the mechanisms of CO2 absorption in these solvents, their regeneration and their processability – especially taking into account their viscosity. While not intended to provide a complete coverage of the existing literature, this review aims at pointing the major findings reported for these new classes of CO2 capture media.

  14. Structural and energetic characterization of anhydrous and hemihydrated 2-mercaptoimidazole: Calorimetric, X-ray diffraction, and computational studies

    International Nuclear Information System (INIS)

    Silva, Ana L.R.; Morais, Victor M.F.; Ribeiro da Silva, Maria D.M.C.; Simões, Ricardo G.; Bernardes, Carlos E.S.

    2016-01-01

    Highlights: • Rotating-bomb combustion calorimetry was used to obtain the enthalpy of formation of crystalline 2-mercaptoimidazole. • Enthalpy of sublimation of 2-mercaptoimidazole was measured by Calvet microcalorimetry. • Enthalpy of interaction between substituents is calculated using isodesmic reactions. • Crystal X-ray diffraction determinations for anhydrous and hemihydrate 2-mercaptoimidazole forms were carried. • Gas-phase enthalpies of formation of 2-mercaptoimidazole and 1,3-dihydro-2H-imidazole-2-thione estimated by the G3 method. - Abstract: This paper reports an experimental and theoretical study on the structural and energetic characterization of the 2-mercaptoimidazole (2-MI) in the solid and in the gaseous phases. The single crystal X-ray diffraction determinations on the anhydrous and hemihydrate 2-MI forms were carried out at T = (296 ± 2) K and T = (150 ± 2) K, respectively, and suggest that in both forms the 2-MI molecule is closer to the thione conformation, albeit some single bond character is possible. The energy of combustion of the title compound was measured by rotating-bomb combustion calorimetry, being used to derive the corresponding enthalpy of formation in the crystalline-phase. The enthalpy of sublimation of 2-MI, at T = 298.15 K, was obtained from high temperature Calvet microcalorimetry measurements. These two parameters yielded the gas-phase enthalpy of formation, allowing the inherent energetic analysis of the molecule. This result was discussed together with the corresponding predictions for 2-MI and its tautomer, 1,3-dihydro-2H-imidazole-2-thione, by the G3 method. The dehydration reaction of 2-MI · 0.5H_2O(cr) was also investigated and the corresponding enthalpy of dehydration was determined by Calvet microcalorimetry.

  15. Recent Advances in Anhydrous Solvents for CO2 Capture: Ionic Liquids, Switchable Solvents, and Nanoparticle Organic Hybrid Materials

    International Nuclear Information System (INIS)

    Park, Youngjune; Lin, Kun-Yi Andrew; Park, Ah-Hyung Alissa; Petit, Camille

    2015-01-01

    CO 2 capture by amine scrubbing, which has a high CO 2 capture capacity and a rapid reaction rate, is the most employed and investigated approach to date. There are a number of recent large-scale demonstrations including the Boundary Dam Carbon Capture Project by SaskPower in Canada that have reported successful implementations of aqueous amine solvent in CO 2 capture from flue gases. The findings from these demonstrations will significantly advance the field of CO 2 capture in the coming years. While the latest efforts in aqueous amine solvents are exciting and promising, there are still several drawbacks to amine-based CO 2 capture solvents including high volatility and corrosiveness of the amine solutions as well as the high parasitic energy penalty during the solvent regeneration step. Thus, in a parallel effort, alternative CO 2 capture solvents, which are often anhydrous, have been developed as the third-generation CO 2 capture solvents. These novel classes of liquid materials include ionic liquids, CO 2 -triggered switchable solvents (i.e., CO 2 -binding organic liquids, reversible ionic liquids), and nanoparticle organic hybrid materials. This paper provides a review of these various anhydrous solvents and their potential for CO 2 capture. Particular attention is given to the mechanisms of CO 2 absorption in these solvents, their regeneration and their processability – especially taking into account their viscosity. While not intended to provide a complete coverage of the existing literature, this review aims at pointing the major findings reported for these new classes of CO 2 capture media.

  16. Wetting behavior of nonpolar nanotubes in simple dipolar liquids for varying nanotube diameter and solute-solvent interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Malay Kumar; Chandra, Amalendu, E-mail: amalen@iitk.ac.in [Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2015-01-21

    Atomistic simulations of model nonpolar nanotubes in a Stockmayer liquid are carried out for varying nanotube diameter and nanotube-solvent interactions to investigate solvophobic interactions in generic dipolar solvents. We have considered model armchair type single-walled nonpolar nanotubes with increasing radii from (5,5) to (12,12). The interactions between solute and solvent molecules are modeled by the well-known Lennard-Jones and repulsive Weeks-Chandler-Andersen potentials. We have investigated the density profiles and microscopic arrangement of Stockmayer molecules, orientational profiles of their dipole vectors, time dependence of their occupation, and also the translational and rotational motion of solvent molecules in confined environments of the cylindrical nanopores and also in their external peripheral regions. The present results of structural and dynamical properties of Stockmayer molecules inside and near atomistically rough nonpolar surfaces including their wetting and dewetting behavior for varying interactions provide a more generic picture of solvophobic effects experienced by simple dipolar liquids without any specific interactions such as hydrogen bonds.

  17. studies dielectric behaviour of some long chain alcohols and their mixtures with a non-polar solvent at various concentration

    International Nuclear Information System (INIS)

    Yaqub, M.; Ahmed, S.S.; Hussain, A.

    2006-01-01

    Dielectric constant, refractive index and the Kirkwood linear correlation factor of 1-propanol, 1-butanol and 1-pentanol in mixtures with carbon tetrachloride at various concentration have been measured at fixed frequency (100 KHz) at 303.15 K. For the study of dielectric properties of polar molecules in a non-polar solvent at different concentrations, polarization per unit volume and excess free-energy of mixing were evaluated at this temperature. In order to study the association of polar molecules in such a non-polar solvent, the Kirkwood correlation factor (g) between molecular pairs, which exists due to the hydrogen bond association suggesting the presence of some dimension in the liquid phase with a number of dimmers, was determined. The refractive index and dielectric constant measurements are expected to shed some light on the configuration of molecules in various mixtures, and give some idea about the specific interactions between components, which decrese with the increase in the concentration of alcohol. All the three mixtures showed different behaviour for the value of correlation factor (g) as a function of concentration. The response of 1-pentanol was broadly identical to that of small chain alcohols. The different behaviour of the correlation factor (g) was interpreted in terms of the Kirkwood-Frohlich theory, as it takes into account, explicitly, such type of short and long range interactions of a mixture of polar molecules with non-polar solvents. (author)

  18. Growth and characterization of polar and nonpolar ZnO film grown on sapphire substrates by using atomic layer deposition

    International Nuclear Information System (INIS)

    Kim, Ki-Wook; Son, Hyo-Soo; Choi, Nak-Jung; Kim, Jihoon; Lee, Sung-Nam

    2013-01-01

    We investigated the electrical and the optical properties of polar and nonpolar ZnO films grown on sapphire substrates with different crystallographic planes. High resolution X-ray results revealed that polar c-plane (0001), nonpolar m-plane (10-10) and a-plane (11-20) ZnO thin films were grown on c-plane, m- and r-sapphire substrates by atomic layer deposition, respectively. Compared with the c-plane ZnO film, nonpolar m-plane and a-plane ZnO films showed smaller surface roughness and anisotropic surface structures. Regardless of ZnO crystal planes, room temperature photoluminescence spectra represented two emissions which consisted of the near bandedge (∼ 380 nm) and the deep level emission (∼ 500 nm). The a-plane ZnO films represented better optical and electrical properties than c-plane ZnO, while m-plane ZnO films exhibited poorer optical and electrical properties than c-plane ZnO. - Highlights: • Growth and characterization of a-, c- and m-plane ZnO film by atomic layer deposition. • The a-plane ZnO represented better optical and electrical properties than c-plane ZnO. • The m-plane ZnO exhibited poorer optical and electrical properties than c-plane ZnO

  19. The nature of carrier localisation in polar and nonpolar InGaN/GaN quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, P., E-mail: philip.dawson@manchester.ac.uk [School of Physics and Astronomy, Photon Science Institute, University of Manchester, Manchester M13 9PL (United Kingdom); Schulz, S. [Photonics Theory Group, Tyndall National Institute, Dyke Parade, Cork (Ireland); Oliver, R. A.; Kappers, M. J.; Humphreys, C. J. [Department of Material Science and Metallurgy, 27 Charles Babbage Road, University of Cambridge, Cambridge CB3 0FS (United Kingdom)

    2016-05-14

    In this paper, we compare and contrast the experimental data and the theoretical predictions of the low temperature optical properties of polar and nonpolar InGaN/GaN quantum well structures. In both types of structure, the optical properties at low temperatures are governed by the effects of carrier localisation. In polar structures, the effect of the in-built electric field leads to electrons being mainly localised at well width fluctuations, whereas holes are localised at regions within the quantum wells, where the random In distribution leads to local minima in potential energy. This leads to a system of independently localised electrons and holes. In nonpolar quantum wells, the nature of the hole localisation is essentially the same as the polar case but the electrons are now coulombically bound to the holes forming localised excitons. These localisation mechanisms are compatible with the large photoluminescence linewidths of the polar and nonpolar quantum wells as well as the different time scales and form of the radiative recombination decay curves.

  20. Control of powdery mildew on glasshouse-grown roses and tomatoes in the Netherlands using anhydrous milk fat and soybean oil emulsions

    NARCIS (Netherlands)

    Wurms, K.V.; Hofland-Zijlstra, Jantineke

    2015-01-01

    Powdery mildew (PM) is a very serious disease affecting glasshouse-grown roses and tomatoes in the Netherlands. Control is limited because of resistance to existing fungicides. Anhydrous milk fat (AMF) and soybean oil (SBO) emulsions were evaluated for control of PM in roses and tomatoes. Both

  1. Immunogold electron microscopic localization of timothy grass (Phleum pratense) pollen major allergens Phl p I and Phl p V after anhydrous fixation in acrolein vapor

    NARCIS (Netherlands)

    Grote, M.; Dolecek, C.; van Ree, R.; Valenta, R.

    1994-01-01

    We used the vapor phase of acrolein as an anhydrous fixative for timothy grass pollen in an immunogold double-labeling localization study of two different major allergens, Phl p I and Phl p V. More than 48 hr of fixation were needed for the subcellular pollen structures to be satisfactorily

  2. Trace element partitioning between ilmenite, armalcolite and anhydrous silicate melt: Implications for the formation of lunar high-Ti mare basalts

    NARCIS (Netherlands)

    Kan Parker, M. van; Mason, P.R.D.; Westrenen, W. van

    2011-01-01

    We performed a series of experiments at high pressures and temperatures to determine the partitioning of a wide range of trace elements between ilmenite (Ilm), armalcolite (Arm) and anhydrous lunar silicate melt, to constrain geochemical models of the formation of titanium-rich melts in the Moon.

  3. Nitrobenzene anti-parallel dimer formation in non-polar solvents

    Directory of Open Access Journals (Sweden)

    Toshiyuki Shikata

    2014-06-01

    Full Text Available We investigated the dielectric and depolarized Rayleigh scattering behaviors of nitrobenzene (NO2-Bz, which is a benzene mono-substituted with a planar molecular frame bearing the large electric dipole moment 4.0 D, in non-polar solvents solutions, such as tetrachloromethane and benzene, at up to 3 THz for the dielectric measurements and 8 THz for the scattering experiments at 20 °C. The dielectric relaxation strength of the system was substantially smaller than the proportionality to the concentration in a concentrated regime and showed a Kirkwood correlation factor markedly lower than unity; gK ∼ 0.65. This observation revealed that NO2-Bz has a tendency to form dimers, (NO2-Bz2, in anti-parallel configurations for the dipole moment with increasing concentration of the two solvents. Both the dielectric and scattering data exhibited fast and slow Debye-type relaxation modes with the characteristic time constants ∼7 and ∼50 ps in a concentrated regime (∼15 and ∼30 ps in a dilute regime, respectively. The fast mode was simply attributed to the rotational motion of the (monomeric NO2-Bz. However, the magnitude of the slow mode was proportional to the square of the concentration in the dilute regime; thus, the mode was assigned to the anti-parallel dimer, (NO2-Bz2, dissociation process, and the slow relaxation time was attributed to the anti-parallel dimer lifetime. The concentration dependencies of both the dielectric and scattering data show that the NO2-Bz molecular processes are controlled through a chemical equilibrium between monomers and anti-parallel dimers, 2NO2-Bz ↔ (NO2-Bz2, due to a strong dipole-dipole interaction between nitro groups.

  4. Effect of polar and non-polar surfaces of ZnO nanostructures on photocatalytic properties

    International Nuclear Information System (INIS)

    Yang Jinghai; Wang Jian; Li Xiuyan; Lang Jihui; Liu Fuzhu; Yang Lili; Zhai Hongju; Gao Ming; Zhao Xiaoting

    2012-01-01

    Highlights: ► Large-scale arrayed ZnO nanocrystals including ZnO hexagonal platforms and hamburger-like samples have been successfully fabricated by a simple hydrothermal method. ► ZnO with hexagonal platform-like morphology exhibited higher photocatalytic activity compared with that of the hamburger-like ZnO nanostructures. ► The theories of expose surfaces and oxygen vacancies were utilized to explain the photocatalytic mechanism. - Abstract: Large-scale arrayed ZnO nanocrystals with two different expose surfaces, including ZnO hexagonal nanoplatforms with the major expose plane of (0 0 0 1) and hamburger-like samples with the nonpolar planes of {101 ¯ 0} mainly exposed, were successfully fabricated by a simple hydrothermal method. Mechanisms for compare the photocatalytic activity of two typical ZnO nanostructures were systematic explained as the key point in the paper. Compared with the hamburger-like ZnO nanostructures, the ZnO with hexagonal platform-like morphology exhibited improved ability on the photocatalytic degradation of Rhodamine B (RhB) in aqueous solution under UV radiation. The relative higher photocatalytic activity of the ZnO hexagonal nanoplatforms was attributed to the exposed polar surfaces and the content of oxygen vacancy on the nanostructures surface. The Zn-terminated (0 0 0 1) polar face and the surface defects are facile to adsorb O 2− and OH − ions, resulting in a greater production rate of O 2 · − and OH· − , hence promoting the photocatalysis reaction.

  5. Evidence of micropore filling for sorption of nonpolar organic contaminants by condensed organic matter.

    Science.gov (United States)

    Ran, Yong; Yang, Yu; Xing, Baoshan; Pignatello, Joseph J; Kwon, Seokjoo; Su, Wei; Zhou, Li

    2013-01-01

    Although microporosity and surface area of natural organic matter (NOM) are crucial for mechanistic evaluation of the sorption process for nonpolar organic contaminants (NOCs), they have been underestimated by the N adsorption technique. We investigated the CO-derived internal hydrophobic microporosity () and specific surface area (SSA) obtained on dry samples and related them to sorption behaviors of NOCs in water for a wide range of condensed NOM samples. The is obtained from the total CO-derived microporosity by subtracting out the contribution of the outer surfaces of minerals and NOM using N adsorption-derived parameters. The correlation between or CO-SSA and fractional organic carbon content () is very significant, demonstrating that much of the microporosity is associated with internal NOM matrices. The average and CO-SSA are, respectively, 75.1 μL g organic carbon (OC) and 185 m g OC from the correlation analysis. The rigid aliphatic carbon significantly contributes to the microporosity of the Pahokee peat. A strong linear correlation is demonstrated between / and the OC-normalized sorption capacity at the liquid or subcooled liquid-state water solubility calculated via the Freundlich equation for each of four NOCs (phenanthrene, naphthalene, 1,3,5-trichlorobenzene, and 1,2-dichlorobenzene). We concluded that micropore filling ("adsorption") contributes to NOC sorption by condensed NOM, but the exact contribution requires knowing the relationship between the dry-state, CO-determined microporosity and the wet-state, NOC-available microporosity of the organic matter. The findings offer new clues for explaining the nonideal sorption behaviors of NOCs. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. Na+ -K+ -2Cl- Cotransporter (NKCC) Physiological Function in Nonpolarized Cells and Transporting Epithelia.

    Science.gov (United States)

    Delpire, Eric; Gagnon, Kenneth B

    2018-03-25

    Two genes encode the Na + -K + -2Cl - cotransporters, NKCC1 and NKCC2, that mediate the tightly coupled movement of 1Na + , 1K + , and 2Cl - across the plasma membrane of cells. Na + -K + -2Cl - cotransport is driven by the chemical gradient of the three ionic species across the membrane, two of them maintained by the action of the Na + /K + pump. In many cells, NKCC1 accumulates Cl - above its electrochemical potential equilibrium, thereby facilitating Cl - channel-mediated membrane depolarization. In smooth muscle cells, this depolarization facilitates the opening of voltage-sensitive Ca 2+ channels, leading to Ca 2+ influx, and cell contraction. In immature neurons, the depolarization due to a GABA-mediated Cl - conductance produces an excitatory rather than inhibitory response. In many cell types that have lost water, NKCC is activated to help the cells recover their volume. This is specially the case if the cells have also lost Cl - . In combination with the Na + /K + pump, the NKCC's move ions across various specialized epithelia. NKCC1 is involved in Cl - -driven fluid secretion in many exocrine glands, such as sweat, lacrimal, salivary, stomach, pancreas, and intestine. NKCC1 is also involved in K + -driven fluid secretion in inner ear, and possibly in Na + -driven fluid secretion in choroid plexus. In the thick ascending limb of Henle, NKCC2 activity in combination with the Na + /K + pump participates in reabsorbing 30% of the glomerular-filtered Na + . Overall, many critical physiological functions are maintained by the activity of the two Na + -K + -2Cl - cotransporters. In this overview article, we focus on the functional roles of the cotransporters in nonpolarized cells and in epithelia. © 2018 American Physiological Society. Compr Physiol 8:871-901, 2018. Copyright © 2018 American Physiological Society. All rights reserved.

  7. Interfacial behavior of polar, weakly polar, and nonpolar compounds bound to activated carbons.

    Science.gov (United States)

    Gun'ko, V M; Turov, V V; Zarko, V I; Goncharuk, O V; Nychiporuk, Yu M; Kozynchenko, O P; Skubiszewska-Zięba, J; Leboda, R; Charmas, B; Balakin, D Yu; Ptushinskii, Yu G

    2013-08-15

    Detailed analysis of the interfacial behavior of water and weakly polar or nonpolar organics adsorbed alone or co-adsorbed onto activated carbons (AC) at different temperatures is a complex problem important for practical applications of adsorbents. Interaction of water, 1-decanol, and n-decane with AC possessing highly developed porosity (pore volume Vp≈1.4-2.3 cm(3)/g, specific surface area S(BET)≈1500-3500 m(2)/g) was studied over a broad temperature range using differential scanning calorimetry (DSC), thermoporometry, (1)H NMR spectroscopy, cryoporometry, and temperature-programmed desorption with mass-spectrometry control methods. Comparison of the pore size distributions (PSD) calculated using the DSC thermoporometry, NMR cryoporometry, and nitrogen adsorption isotherms allows us to determine localization of adsorbates in different pores, as well as changes in the PSD of AC due to freezing of adsorbates in pores. Theoretical calculations (using ab initio HF/6-31G(d,p), DFT B3LYP/6-31G(d,p), and PM7 methods) explain certain aspects of the interfacial behavior of water, decane, and decanol adsorbed onto AC that appear in the experimental data. Obtained results show strong temperature dependence (above and below the freezing point, Tf, of bulk liquids) of the interfacial behavior of adsorbates on the textural characteristics and hydrophilic/hydrophobic properties of AC and the adsorbate amounts that affect the distributions of adsorbates unfrozen at T

  8. Nonpolar ZnO film growth and mechanism for anisotropic in-plane strain relaxation

    International Nuclear Information System (INIS)

    Pant, P.; Budai, J.D.; Narayan, J.

    2010-01-01

    Using high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction, we investigated the strain relaxation mechanisms for nonpolar (1 1 -2 0) a-plane ZnO epitaxy on (1 -1 0 2) r-plane sapphire, where the in-plane misfit ranges from -1.5% for the [0 0 0 1]ZnO-parallel [1 -1 0 -1]sapphire to -18.3% for the [-1 1 0 0]ZnO-parallel [-1 -1 2 0]sapphire direction. For the large misfit [-1 1 0 0]ZnO direction the misfit strains are fully relaxed at the growth temperature, and only thermal misfit and defect strains, which cannot be relaxed fully by slip dislocations, remain on cooling. For the small misfit direction, lattice misfit is not fully relaxed at the growth temperature. As a result, additive unrelaxed lattice and thermal misfit and defect strains contribute to the measured strain. Our X-ray diffraction measurements of lattice parameters show that the anisotropic in-plane biaxial strain leads to a distortion of the hexagonal symmetry of the ZnO basal plane. Based on the anisotropic strain relaxation observed along the orthogonal in-plane [-1 1 0 0] and [0 0 0 1]ZnO stress directions and our HRTEM investigations of the interface, we show that the plastic relaxation occurring in the small misfit direction [0 0 0 1]ZnO by dislocation nucleation is incomplete. These results are consistent with the domain-matching paradigm of a complete strain relaxation for large misfits and a difficulty in relaxing the film strain for small misfits.

  9. Matrix tablets: the effect of hydroxypropyl methylcellulose/anhydrous dibasic calcium phosphate ratio on the release rate of a water-soluble drug through the gastrointestinal tract I. In vitro tests.

    Science.gov (United States)

    Mamani, Pseidy L; Ruiz-Caro, Roberto; Veiga, María D

    2012-12-01

    Different hydroxypropyl methylcellulose (HPMC)/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed aiming to evaluate the influence of both components ratio in the control release of a water-soluble drug (theophylline). In order to characterise the matrix tablets, swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralised water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid). The HPMC/ADCP ratio has turned out to be the determinant in the matrix behaviour: the HPMC characteristic swelling behaviour was modulated, in some cases, by the ADCP characteristic acidic dissolution. When the HPMC/ADCP ratio was ≥0.69, buoyancy, continuous swelling and low theophylline dissolution rate from the matrices (H1, H2 and H3) were observed in all dissolution media. Consequently, these formulations could be adequate as gastro-retentive drug delivery systems. Additionally, HPMC/ADCP ratio ≤0.11 (H5 and H6) induces a pH-dependent drug release which could be applied to design control drug release enteric formulations (with a suitable enteric coating). Finally, a HPMC/ADCP ratio between 0.11 and 0.69 (H4) yield a gastrointestinal controlled drug release, due to its time-dependent buoyancy (7 h) and a total drug delivery in 17 h in simulated colonic fluid.

  10. Anhydric maleic functionalization and polyethylene glycol grafting of lactide-co-trimethylene carbonate copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Díaz, A.; Valle, L.; Franco, L. del [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Sarasua, J.R. [Department of Mining-Metallurgy Engineering and Materials Science, University of the Basque Country (UPV/EHU), Bilbao (Spain); Estrany, F. [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Puiggalí, J., E-mail: Jordi.Puiggali@upc.es [Department of Mining-Metallurgy Engineering and Materials Science, University of the Basque Country (UPV/EHU), Bilbao (Spain)

    2014-09-01

    Lactide and trimethylene carbonate copolymers were successfully grafted with polyethylene glycol via previous functionalization with maleic anhydride and using N,N′-diisopropylcarbodiimide as condensing agent. Maleinization led to moderate polymer degradation. Specifically, the weight average molecular weight decreased from 36,200 to 30,200 g/mol for the copolymer having 20 mol% of trimethylene carbonate units. Copolymers were characterized by differential scanning calorimetry, thermogravimetry and X-ray diffraction. Morphology of spherulites and lamellar crystals was evaluated with optical and atomic force microscopies, respectively. The studied copolymers were able to crystallize despite the randomness caused by the trimethylene carbonate units and the lateral groups. Contact angle measurements indicated that PEG grafted copolymers were more hydrophilic than parent copolymers. This feature justified that enzymatic degradation in lipase medium and proliferation of both epithelial-like and fibroblast-like cells were enhanced. Grafted copolymers were appropriate to prepare regular drug loaded microspheres by the oil-in-water emulsion method. Triclosan release from loaded microspheres was evaluated in two media. - Highlights: • Pegylated copolymers of lactide and trimethylene carbonate have been synthesized. • Grafting with polyethylene glycol was able via maleic anhydride functionalization. • Drug-loaded microspheres could be prepared from new pegylated copolymers. • Hydrophilicity of lactide/trimethylene carbonate copolymers increased by pegylation. • New pegylated copolymers supported cell adhesion and proliferation.

  11. Toward Anhydrous Proton Conductivity Based on Imidazole Functionalized Mesoporous Silica/Nafion Composite Membranes

    International Nuclear Information System (INIS)

    Amiinu, Ibrahim Saana; Li, Wei; Wang, Guangjin; Tu, Zhengkai; Tang, Haolin; Pan, Mu; Zhang, Haining

    2015-01-01

    Highlights: • Imidazole-functionalized mesoporous silica/Nafion composite is formed. • Electrostatic interaction between ionic clusters leads to enhanced molecular rigidity and T g . • Charge transfer resistance decreases with increase in temperature up to 130 °C. • The composite membrane exhibited considerable stability over 70 h at 130 °C. - Abstract: Although Nafion is regarded as the most preferred electrolyte membrane and often used as a benchmark for comparative evaluation of other electrolyte membranes, its wide spread for commercial PEM fuel cells is limited by the poor electrochemical properties at elevated temperatures and low relative humidity conditions. Herein, sol–gel synthesized mesoporous silica functionalized with a protogenic molecule (imidazole) is introduced into the Nafion matrix via a colloid mediated process. The formation of a stable colloid enables homogeneous dispersion of the silica-imidazole nanoparticles without aggregation. Under non-humidified conditions, the amphoteric and self-dissociative character of the tethered imidazole within the matrix functions as a transporting medium to facilitate proton conductivity. The structural and chemical phases are characterized, and qualitatively evaluated by XRD, TEM, FT-IR, TGA, and DMA. The results show that the average proton conductivity of the composite membrane with the optimal amount of functionalized nanoparticles increases progressively to 1.06 × 10 −2 S cm −1 at 130 °C, corresponding to an activation energy of 6.95 kJ mol −1 under non-humidified conditions. The mechanism governing the dynamics of proton conductivity and structural limitations as a function of temperature is discussed

  12. Two complementary reversed-phase separations for comprehensive coverage of the semipolar and nonpolar metabolome.

    Science.gov (United States)

    Naser, Fuad J; Mahieu, Nathaniel G; Wang, Lingjue; Spalding, Jonathan L; Johnson, Stephen L; Patti, Gary J

    2018-02-01

    Although it is common in untargeted metabolomics to apply reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) methods that have been systematically optimized for lipids and central carbon metabolites, here we show that these established protocols provide poor coverage of semipolar metabolites because of inadequate retention. Our objective was to develop an RPLC approach that improved detection of these metabolites without sacrificing lipid coverage. We initially evaluated columns recently released by Waters under the CORTECS line by analyzing 47 small-molecule standards that evenly span the nonpolar and semipolar ranges. An RPLC method commonly used in untargeted metabolomics was considered a benchmarking reference. We found that highly nonpolar and semipolar metabolites cannot be reliably profiled with any single method because of retention and solubility limitations of the injection solvent. Instead, we optimized a multiplexed approach using the CORTECS T3 column to analyze semipolar compounds and the CORTECS C 8 column to analyze lipids. Strikingly, we determined that combining these methods allowed detection of 41 of the total 47 standards, whereas our reference RPLC method detected only 10 of the 47 standards. We then applied credentialing to compare method performance at the comprehensive scale. The tandem method showed more than a fivefold increase in credentialing coverage relative to our RPLC benchmark. Our results demonstrate that comprehensive coverage of metabolites amenable to reversed-phase separation necessitates two reconstitution solvents and chromatographic methods. Thus, we suggest complementing HILIC methods with a dual T3 and C 8 RPLC approach to increase coverage of semipolar metabolites and lipids for untargeted metabolomics. Graphical abstract Analysis of semipolar and nonpolar metabolites necessitates two reversed-phase chromatography (RPLC) methods, which extend metabolome coverage more

  13. Characterization and growth mechanism of nonpolar and semipolar GaN layers grown on patterned sapphire substrates

    International Nuclear Information System (INIS)

    Okada, Narihito; Tadatomo, Kazuyuki

    2012-01-01

    Nonpolar and semipolar GaN layers with markedly improved crystalline quality can be obtained by selective-area growth from the sapphire sidewalls of patterned sapphire substrates (PSSs). In this paper, we review the crystalline qualities of GaN layers grown on PSSs and their growth mechanism. We grew semipolar {1 1 −2 2} and {1 0 −1 1} GaN layers on r- and n-PSSs. The crystalline qualities of the GaN layers grown on the PSSs were higher than those of GaN layers grown directly on heteroepitaxial substrates. To reveal the growth mechanism of GaN layers grown on PSSs, we also grew various nonpolar and semipolar GaN layers such as m-GaN on a-PSS, {1 1 −2 2} GaN on r-PSS, {1 0 − 1  1} GaN on n-PSS, m-GaN on c-PSS and a-GaN on m-PSS. It was found that the nucleation of GaN on the c-plane-like sapphire sidewall results in selective growth from the sapphire sidewall, and nonpolar or semipolar GaN can be obtained. Finally, we demonstrated a light-emitting diode fabricated on a {1 1 −2 2} GaN layer grown on an r-PSS. (paper)

  14. Polar and nonpolar organic polymer-based monolithic columns for capillary electrochromatography and high-performance liquid chromatography.

    Science.gov (United States)

    Rathnasekara, Renuka; Khadka, Shantipriya; Jonnada, Murthy; El Rassi, Ziad

    2017-01-01

    This review article is a continuation of the previous reviews on the area of monolithic columns covering the progress made in the field over the last couple of years from the beginning of the second half of 2014 until the end of the first half of 2016. It summarizes and evaluates the evolvement of both polar and nonpolar organic monolithic columns and their use in hydrophilic interaction LC and CEC and reversed-phase chromatography and RP-CEC. The review article discusses the results reported in a total of 62 references. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Non-polar InGaN quantum dot emission with crystal-axis oriented linear polarization

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Benjamin P. L., E-mail: benjamin.reid@physics.ox.ac.uk; Chan, Christopher C. S.; Taylor, Robert A. [Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Kocher, Claudius [Department of Physics, University of Konstanz, Konstanz 78457 (Germany); Zhu, Tongtong; Oehler, Fabrice; Oliver, Rachel A. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

    2015-04-27

    Polarization sensitive photoluminescence is performed on single non-polar InGaN quantum dots. The studied InGaN quantum dots are found to have linearly polarized emission with a common polarization direction defined by the [0001] crystal axis. Around half of ∼40 studied dots have a polarization degree of 1. For those lines with a polarization degree less than 1, we can resolve fine structure splittings between −800 μeV and +800 μeV, with no clear correlation between fine structure splitting and emission energy.

  16. M-CARS and EFISHG study of the influence of a static electric field on a non-polar molecule

    Science.gov (United States)

    Capitaine, E.; Louot, C.; Ould-Moussa, N.; Lefort, C.; Kaneyasu, J. F.; Kano, H.; Pagnoux, D.; Couderc, V.; Leproux, P.

    2016-03-01

    The influence of a static electric field on a non-polar molecule has been studied by means of multiplex coherent anti-Stokes Raman scattering (M-CARS). A parallel measurement of electric field induced second harmonic generation (EFISHG) has also been led. Both techniques suggest a reorientation of the molecule due to the presence of an electric field. This phenomenon can be used to increase the chemical selectivity and the signal to non-resonant background ratio, namely, the sensitivity of the M-CARS spectroscopy.

  17. The flotation of Roşia Poieni copper ore in column machine, with non-polar oils addition

    Directory of Open Access Journals (Sweden)

    Ciocani V.

    2005-11-01

    Full Text Available The most important natural resource of copper in Romania is the ore deposit of Roşia Poieni. At present, the utilization of Roşia Poieni poorphyry copper ore is possible by extraction in quarry of the mass ore and mineral processing into a technological flux with modest results for the value of metal recovery in concentrate 70-72 % and an average contents of 16,5 % Cu. Our researches were directed to studies regarding test and utilisation of special procedure of flotation – addition of the non-polar oil – applied to advanced grinding ore with column type machines.

  18. Effect of pulverization of the bulk powder on the hydration of creatine anhydrate tablets and their pharmaceutical properties.

    Science.gov (United States)

    Sakata, Yukoh; Shiraishi, Sumihiro; Otsuka, Makoto

    2005-12-10

    The hydration behavior and expansion properties of untreated and pulverized creatine anhydrate (CRA) tablets were studied under 60 and 75%RH at 25 degrees C by using differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The tablet hardness of untreated and pulverized CRA tablets was significantly decreased after hydration. There was a linear relationship between the degree of hydration and the tablet hardness of untreated CRA tablets compressed at 1000 kg/cm2. In contrast, the relationship between the degree of hydration and the tablet hardness of pulverized CRA tablets was nonlinear. These results suggest that the reduction in hardness of pulverized CRA tablets does not depend solely on the hydration level of crystal water. PXRD analysis indicated that the diffraction pattern of the pulverized CRA powder was similar to that of the untreated CRA powder. However, the diffraction intensity of the pulverized CRA powder was slightly lower than that of the untreated CRA powder at high angle. The micropore radius of both untreated and pulverized CRA tablets was significantly increased after hydration, but analysis of the relationship between micropore radius and fractional hydration of crystal water showed that untreated CRA tablets were more affected than pulverized CRA tablets. Therefore, the reduction in tablet hardness depends not only on the hydration behavior but also on the crystal orientation of the CRA powder.

  19. Synthesis and characterizations of two anhydrous metal borophosphates: MIII2BP3O12 (M=Fe, In)

    International Nuclear Information System (INIS)

    Zhang Weilong; Lin Chensheng; Geng Lei; Li Yeyu; Zhang Hao; He Zhangzhen; Cheng Wendan

    2010-01-01

    Two members of M III 2 BP 3 O 12 borophosphates, namely Fe 2 BP 3 O 12 and In 2 BP 3 O 12 , were synthesized by the solid-state method and characterized by the X-ray single crystal diffraction, the powder diffraction and the electron microscopy. They both crystallize in the hexagonal system, space group P6(3)/m (no. 176) and feature 3D architectures, build up of the M 2 O 9 units and B(PO 4 ) 3 groups via sharing the corners; however, they are not isomorphic for the different crystallographically distinct atomic positions. Optical property measurements of both compounds and magnetic susceptibility measurements of Fe 2 BP 3 O 12 also have been performed. Moreover, in order to gain further insights into the relationship between physical properties and band structure of the M III 2 BP 3 O 12 borophosphates, theoretical calculations based on density functional theory (DFT) were performed using the total-energy code CASTEP. - Graphical abstract: Two anhydrous metal borophosphates of M III 2 BP 3 O 12 (M=Fe, In) have been prepared and characterized. They both crystallize in the hexagonal system, space group P6(3)/m (no. 176) and feature 3D architectures build up of the M 2 O 9 units and B(PO 4 ) 3 groups via sharing the corners, but they are not isomorphic for the different crystallographically distinct atomic positions.

  20. High DNA stability in white blood cells and buffy coat lysates stored at ambient temperature under anoxic and anhydrous atmosphere.

    Directory of Open Access Journals (Sweden)

    Anne-Lise Fabre

    Full Text Available Conventional storage of blood-derived fractions relies on cold. However, lately, ambient temperature preservation has been evaluated by several independent institutions that see economic and logistic advantages in getting rid of the cold chain. Here we validated a novel procedure for ambient temperature preservation of DNA in white blood cell and buffy coat lysates based on the confinement of the desiccated biospecimens under anoxic and anhydrous atmosphere in original hermetic minicapsules. For this validation we stored encapsulated samples either at ambient temperature or at several elevated temperatures to accelerate aging. We found that DNA extracted from stored samples was of good quality with a yield of extraction as expected. Degradation rates were estimated from the average fragment size of denatured DNA run on agarose gels and from qPCR reactions. At ambient temperature, these rates were too low to be measured but the degradation rate dependence on temperature followed Arrhenius' law, making it possible to extrapolate degradation rates at 25°C. According to these values, the DNA stored in the encapsulated blood products would remain larger than 20 kb after one century at ambient temperature. At last, qPCR experiments demonstrated the compatibility of extracted DNA with routine DNA downstream analyses. Altogether, these results showed that this novel storage method provides an adequate environment for ambient temperature long term storage of high molecular weight DNA in dehydrated lysates of white blood cells and buffy coats.

  1. High DNA stability in white blood cells and buffy coat lysates stored at ambient temperature under anoxic and anhydrous atmosphere

    Science.gov (United States)

    Luis, Aurélie; Colotte, Marthe; Tuffet, Sophie; Bonnet, Jacques

    2017-01-01

    Conventional storage of blood-derived fractions relies on cold. However, lately, ambient temperature preservation has been evaluated by several independent institutions that see economic and logistic advantages in getting rid of the cold chain. Here we validated a novel procedure for ambient temperature preservation of DNA in white blood cell and buffy coat lysates based on the confinement of the desiccated biospecimens under anoxic and anhydrous atmosphere in original hermetic minicapsules. For this validation we stored encapsulated samples either at ambient temperature or at several elevated temperatures to accelerate aging. We found that DNA extracted from stored samples was of good quality with a yield of extraction as expected. Degradation rates were estimated from the average fragment size of denatured DNA run on agarose gels and from qPCR reactions. At ambient temperature, these rates were too low to be measured but the degradation rate dependence on temperature followed Arrhenius’ law, making it possible to extrapolate degradation rates at 25°C. According to these values, the DNA stored in the encapsulated blood products would remain larger than 20 kb after one century at ambient temperature. At last, qPCR experiments demonstrated the compatibility of extracted DNA with routine DNA downstream analyses. Altogether, these results showed that this novel storage method provides an adequate environment for ambient temperature long term storage of high molecular weight DNA in dehydrated lysates of white blood cells and buffy coats. PMID:29190767

  2. Reactive Precipitation of Anhydrous Alkali Sulfide Nanocrystals with Concomitant Abatement of Hydrogen Sulfide and Cogeneration of Hydrogen.

    Science.gov (United States)

    Li, Xuemin; Zhao, Yangzhi; Brennan, Alice; McCeig, Miranda; Wolden, Colin A; Yang, Yongan

    2017-07-21

    Anhydrous alkali sulfide (M 2 S, M=Li or Na) nanocrystals (NCs) are important materials central to the development of next generation cathodes and solid-state electrolytes for advanced batteries, but not commercially available at present. This work reports an innovative method to directly synthesize M 2 S NCs through alcohol-mediated reactions between alkali metals and hydrogen sulfide (H 2 S). In the first step, the alkali metal is complexed with alcohol in solution, forming metal alkoxide (ROM) and releasing hydrogen (H 2 ). Next, H 2 S is bubbled through the ROM solution, where both chemicals are completely consumed to produce phase-pure M 2 S NC precipitates and regenerate alcohol that can be recycled. The M 2 S NCs morphology may be tuned through the choice of the alcohol and solvent. Both synthetic steps are thermodynamically favorable (ΔG m o <-100 kJ mol -1 ), proceeding rapidly to completion at ambient temperature with almost 100 % atom efficiency. The net result, H 2 S+2 m→M 2 S+H 2 , makes good use of a hazardous chemical (H 2 S) and delivers two value-added products that naturally phase separate for easy recovery. This scalable approach provides an energy-efficient and environmentally benign solution to the production of nanostructured materials required in emerging battery technologies. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Methods for the preparation of ultra-pure anhydrous zirconium tetrafluoride from zirconium tetraborohydride, researches in connection with halide glasses

    International Nuclear Information System (INIS)

    Tortevois, R.

    1990-01-01

    The synthesis of ultrapure zirconium tetrafluoride, the main component of fluorozirconate based optical fibers, was successfully attempted from zirconium tetraborohydride. Of the fluorinating agents used, nitrogen trifluoride doesn't react with zirconium tetraborohydride while xenon difluoride reacts too violently and leads to phases which contain boron. The fluorination in a compatible solvent enabled us to minimize the degradation. The best results were obtained with the fluorination of Zr(BH 4 ) 4 dissolved in CFCl 3 at -40 deg C by anhydrous HF. Using several analytical methods such as graphite furnace atomic absorption and proton activation, we analyzed the purity. The degree of transition element impurities is less than the ppm level for ZrF 4 . The dehydration of ZrF 4 ,H 2 O and ZrF 4 ,3H 2 O at room temperature by CIF 3 in gaseous and liquid state was also investigated. At exceptionally low temperature, this process allows oxide and oxyfluoride components to be reduced

  4. High molecular weight non-polar hydrocarbons as pure model substances and in motor oil samples can be ionized without fragmentation by atmospheric pressure chemical ionization mass spectrometry.

    Science.gov (United States)

    Hourani, Nadim; Kuhnert, Nikolai

    2012-10-15

    High molecular weight non-polar hydrocarbons are still difficult to detect by mass spectrometry. Although several studies have targeted this problem, lack of good self-ionization has limited the ability of mass spectrometry to examine these hydrocarbons. Failure to control ion generation in the atmospheric pressure chemical ionization (APCI) source hampers the detection of intact stable gas-phase ions of non-polar hydrocarbon in mass spectrometry. Seventeen non-volatile non-polar hydrocarbons, reported to be difficult to ionize, were examined by an optimized APCI methodology using nitrogen as the reagent gas. All these analytes were successfully ionized as abundant and intact stable [M-H](+) ions without the use of any derivatization or adduct chemistry and without significant fragmentation. Application of the method to real-life hydrocarbon mixtures like light shredder waste and car motor oil was demonstrated. Despite numerous reports to the contrary, it is possible to ionize high molecular weight non-polar hydrocarbons by APCI, omitting the use of additives. This finding represents a significant step towards extending the applicability of mass spectrometry to non-polar hydrocarbon analyses in crude oil, petrochemical products, waste or food. Copyright © 2012 John Wiley & Sons, Ltd.

  5. Concept medium programme

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    2005-01-01

    The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program......The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program...

  6. A study of new anhydrous, conducting membranes based on composites of aprotic ionic liquid and cross-linked SPEEK for fuel cell application

    International Nuclear Information System (INIS)

    Malik, Rajender Singh; Verma, Pawan; Choudhary, Veena

    2015-01-01

    Highlights: • New composite membranes based on SPEEK/EG/IL were fabricated. • Composite membranes exhibit good thermal stability than neat SPEEK and XSPEEK membrane. • Proton conductivity of all composite membranes increased with temperature and amount of ionic liquid. • Proton conductivity was measured under anhydrous condition in the temperature ranging from 30–140 °C. - Abstract: The present study describe the preparation and characterisation of anhydrous proton conducting composite membranes based on sulfonated poly(ether ether ketone) [SPEEK–degree of sulfonation 70–72%]/ethylene glycol [EG]/ionic liquid by solution casting method using water: ethanol (50:50) as solvent. For this purpose several composite membranes were prepared by mixing solution of SPEEK/ethylene glycol (67:33 wt %) in water:ethanol with varying amounts of 1-butyl-3-methyl-imidazolium trifluromethanesulfonate [bmim][OTf] ionic liquid. The cross-linking of SPEEK was carried out by thermal treatment i.e. by heating in vacuum oven at 80 °C (2 h), 100 °C (2 h), 120 °C (2 h) and 135 °C for 16 h. Ethylene glycol was used as a cross-linker for SPEEK to reduce the leaching out of ionic liquid and enhance the mechanical strength of SPEEK membranes. The membranes were characterized for thermal [thermogravimetry analysis], structural [FTIR–ATR], proton conductivity, morphology (XRD, SEM) and leaching out of ionic liquid with water. FTIR studies clearly showed the interactions between SPEEK, EG and ionic liquid. The proton conductivity and dynamic mechanical properties of the composite membranes were investigated at elevated temperature and under anhydrous conditions. Proton conductivity of all the membranes measured in the temperature range of 30–140 °C under anhydrous conditions was in the range of 10 −3 Scm −1 which showed an increase with increase in temperature and amount of ionic liquid

  7. Determining the amount of anhydrous alcohol evaporated in vertical cylindrical tanks; Determinacao da quantidade de alcool etilico anidro evaporado em tanques cilindricos verticais

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Elcio Cruz de [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    In order to assess the anhydrous alcohol evaporated amount in vertical cylindrical tanks was developed a calculation methodology based on the rate of mass transfer of the product, the Reynolds number and the mass transfer coefficient. An Excel spreadsheet was prepared with data entry of the tank and physical and chemical properties of the product (temperature and density). For a temperature of 50 deg C, the volume evaporated reaches values of 0.8% by day. (author)

  8. On the interplay of point defects and Cd in non-polar ZnCdO films

    International Nuclear Information System (INIS)

    Zubiaga, A.; Reurings, F.; Tuomisto, F.; Plazaola, F.; García, J. A.; Kuznetsov, A. Yu.; Egger, W.; Zúñiga-Pérez, J.; Muñoz-Sanjosé, V.

    2013-01-01

    Non-polar ZnCdO films, grown over m- and r-sapphire with a Cd concentration ranging between 0.8% and 5%, have been studied by means of slow positron annihilation spectroscopy (PAS) combined with chemical depth profiling by secondary ion mass spectroscopy and Rutherford back-scattering. Vacancy clusters and Zn vacancies with concentrations up to 10 17 cm −3 and 10 18 cm −3 , respectively, have been measured inside the films. Secondary ion mass spectroscopy results show that most Cd stays inside the ZnCdO film but the diffused atoms can penetrate up to 1.3 μm inside the ZnO buffer. PAS results give an insight to the structure of the meta-stable ZnCdO above the thermodynamical solubility limit of 2%. A correlation between the concentration of vacancy clusters and Cd has been measured. The concentration of Zn vacancies is one order of magnitude larger than in as-grown non-polar ZnO films and the vacancy cluster are, at least partly, created by the aggregation of smaller Zn vacancy related defects. The Zn vacancy related defects and the vacancy clusters accumulate around the Cd atoms as a way to release the strain induced by the substitutional Cd Zn in the ZnO crystal.

  9. On the interplay of point defects and Cd in non-polar ZnCdO films

    Energy Technology Data Exchange (ETDEWEB)

    Zubiaga, A.; Reurings, F.; Tuomisto, F. [Department of Applied Physics, Aalto University, P.O. Box 11100, 00076 Aalto, Espoo (Finland); Plazaola, F. [Elektrizitatea eta Elektronika/Fisika Aplikatua II Sailak, Euskal Herriko Unibertsitatea, Posta Kutxatila 644, 48080 Bilbao (Spain); Garcia, J. A. [Fisika Aplikatua II Saila, Euskal Herriko Unibertsitatea, Posta Kutxatila 644, 48080 Bilbao (Spain); Kuznetsov, A. Yu. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, NO-0316 Oslo (Norway); Egger, W. [Inst. fuer Angewandte Physik und Messtechnik, Univ. der Bundeswehr Muenchen, 87755 Neubiberg (Germany); Zuniga-Perez, J. [CRHEA CNRS, F-06560 Valbonne (France); Munoz-Sanjose, V. [Dept. de Fisica Aplicada i Electromagnetisme, c/ Doctor Moliner 50, E-46100 Burjassot (Valencia) (Spain)

    2013-01-14

    Non-polar ZnCdO films, grown over m- and r-sapphire with a Cd concentration ranging between 0.8% and 5%, have been studied by means of slow positron annihilation spectroscopy (PAS) combined with chemical depth profiling by secondary ion mass spectroscopy and Rutherford back-scattering. Vacancy clusters and Zn vacancies with concentrations up to 10{sup 17} cm{sup -3} and 10{sup 18} cm{sup -3}, respectively, have been measured inside the films. Secondary ion mass spectroscopy results show that most Cd stays inside the ZnCdO film but the diffused atoms can penetrate up to 1.3 {mu}m inside the ZnO buffer. PAS results give an insight to the structure of the meta-stable ZnCdO above the thermodynamical solubility limit of 2%. A correlation between the concentration of vacancy clusters and Cd has been measured. The concentration of Zn vacancies is one order of magnitude larger than in as-grown non-polar ZnO films and the vacancy cluster are, at least partly, created by the aggregation of smaller Zn vacancy related defects. The Zn vacancy related defects and the vacancy clusters accumulate around the Cd atoms as a way to release the strain induced by the substitutional Cd{sub Zn} in the ZnO crystal.

  10. On the interplay of point defects and Cd in non-polar ZnCdO films

    Science.gov (United States)

    Zubiaga, A.; Reurings, F.; Tuomisto, F.; Plazaola, F.; García, J. A.; Kuznetsov, A. Yu.; Egger, W.; Zúñiga-Pérez, J.; Muñoz-Sanjosé, V.

    2013-01-01

    Non-polar ZnCdO films, grown over m- and r-sapphire with a Cd concentration ranging between 0.8% and 5%, have been studied by means of slow positron annihilation spectroscopy (PAS) combined with chemical depth profiling by secondary ion mass spectroscopy and Rutherford back-scattering. Vacancy clusters and Zn vacancies with concentrations up to 1017 cm-3 and 1018 cm-3, respectively, have been measured inside the films. Secondary ion mass spectroscopy results show that most Cd stays inside the ZnCdO film but the diffused atoms can penetrate up to 1.3 μm inside the ZnO buffer. PAS results give an insight to the structure of the meta-stable ZnCdO above the thermodynamical solubility limit of 2%. A correlation between the concentration of vacancy clusters and Cd has been measured. The concentration of Zn vacancies is one order of magnitude larger than in as-grown non-polar ZnO films and the vacancy cluster are, at least partly, created by the aggregation of smaller Zn vacancy related defects. The Zn vacancy related defects and the vacancy clusters accumulate around the Cd atoms as a way to release the strain induced by the substitutional CdZn in the ZnO crystal.

  11. The Interstellar Medium

    CERN Document Server

    Lequeux, James

    2005-01-01

    Describing interstellar matter in our galaxy in all of its various forms, this book also considers the physical and chemical processes that are occurring within this matter. The first seven chapters present the various components making up the interstellar matter and detail the ways that we are able to study them. The following seven chapters are devoted to the physical, chemical and dynamical processes that control the behaviour of interstellar matter. These include the instabilities and cloud collapse processes that lead to the formation of stars. The last chapter summarizes the transformations that can occur between the different phases of the interstellar medium. Emphasizing methods over results, "The Interstellar Medium" is written for graduate students, for young astronomers, and also for any researchers who have developed an interest in the interstellar medium.

  12. Material and device studies for the development of ultra-violet light emitting diodes (UV-LEDS) along polar, non-polar and semi-polar directions

    Science.gov (United States)

    Chandrasekaran, Ramya

    Over the past few years, significant effort was dedicated to the development of ultraviolet light emitting diodes (UV-LEDs) for a variety of applications. Such applications include chemical and biological detection, water purification and solid-state lighting. III-Nitride LEDs based on multiple quantum wells (MQWs) grown along the conventional [0001] (polar) direction suffer from the quantum confined Stark effect (QCSE), due to the existence of strong electric fields that arise from spontaneous and piezoelectric polarization. Thus, there is strong motivation to develop MQW-based III-nitride LED structures grown along non-polar and semi-polar directions. The goal of this dissertation is to develop UV-LEDs along the [0001] polar and [11 2¯ 0] non-polar directions by the method of Molecular Beam Epitaxy (MBE). The polar and non-polar LEDs were grown on the C-plane and R-plane sapphire substrates respectively. This work is a combination of materials science studies related to the nucleation, growth and n- and p-type doping of III-nitride films on these two substrates, as well as device studies related to fabrication and characterization of UV-LEDs. It was observed that the crystallographic orientation of the III-nitride films grown on R-plane sapphire depends strongly on the kinetic conditions of growth of the Aluminum Nitride (AIN) buffer. Specifically, growth of the AIN buffer under group III-rich conditions leads to nitride films having the (11 2¯ 0) non polar planes parallel to the sapphire surface, while growth of the buffer under nitrogen rich conditions leads to nitride films with the (11 2¯ 6) semi-polar planes parallel to the sapphire surface. The electron concentration and mobility for the films grown along the polar, non-polar and semi-polar directions were investigated. P-type doping of Gallium Nitride (GaN) films grown on the nonpolar (11 2¯ 0) plane do not suffer from polarity inversion and thus the material was doped p-type with a hole concentration

  13. Optical recording medium

    International Nuclear Information System (INIS)

    Andriech, A.; Bivol, V.; Tridukh, G.; Tsiuleanu, D.

    2002-01-01

    The invention relates of the micro- and optoelectronics, computer engineering ,in particular, to tjhe optical information media and may be used in hilography. Summary of the invention consists in that the optical image recording medium, containing a dielectric substrates, onto one surface of which there are placed in series a transparent electricity conducting layer, a photo sensitive recording layer of chalcogenic glass and a thin film electrode of aluminium, is provided with an optically transparent protective layer, applied into the thin film electrode. The result of the invention consists in excluding the dependence of chemical processes course into the medium upon environmental conditions

  14. Roentgen contrast medium

    International Nuclear Information System (INIS)

    Tamborski, C.

    1989-01-01

    The patent deals with a roentgen contrast medium containing a perfluorinebrominealkylether of the formula C m F 2m+1 OC n F 2n Br dispersed in water, preferentially in the presence of a non-ionic dispersing agent such as a fluorinated amidoaminoxide. 2 tabs

  15. Radon in geological medium

    Energy Technology Data Exchange (ETDEWEB)

    Hricko, J [GEOCOMPLEX, a.s., Bratislava (Slovakia)

    1996-12-31

    The paper presented deals with behavior of the radon in geological medium and with some results of the radon survey in Bratislava and Kosice regions. 1) The a{sub v} has been detected in the holes 0.80 m deep. The density of observations - 3 reference areas (one represents 20 stations) per 1 km{sup 2}. The radon risk maps in 1:25000 and 1:50000 scales have been compiled. The 56.8% of the project area lies in low radon risk, 37.6% in medium radon risk and 5.6% in high radon risk. Follow-up monitoring of the equivalent volume radon activity (EVRA) at the flats, located in the areas with high radon risk of the surface layer, has showed values several times higher than Slovak limits (Marianka, Raca, Vajnory). The evidence that neotectonic is excellent medium for rising up emanation to the subsurface layer, is shown on the map. The tectonic zone of Liscie udolie in Bratislava-Karlova Ves area has been clearly detected by profile radon survey (a{sub v} > 50 kBq/m{sup 3}). 2) At present, northern half of the area of Kosice in question was covered by radon survey. The low and medium radon risks have been observed here, while localities with high radon risk are small in extent. The part of radon risk and soil permeability map from northern Kosice area is shown. (J.K.) 3 figs., 2 refs.

  16. Radon in geological medium

    International Nuclear Information System (INIS)

    Hricko, J.

    1995-01-01

    The paper presented deals with behavior of the radon in geological medium and with some results of the radon survey in Bratislava and Kosice regions. 1) The a v has been detected in the holes 0.80 m deep. The density of observations - 3 reference areas (one represents 20 stations) per 1 km 2 . The radon risk maps in 1:25000 and 1:50000 scales have been compiled. The 56.8% of the project area lies in low radon risk, 37.6% in medium radon risk and 5.6% in high radon risk. Follow-up monitoring of the equivalent volume radon activity (EVRA) at the flats, located in the areas with high radon risk of the surface layer, has showed values several times higher than Slovak limits (Marianka, Raca, Vajnory). The evidence that neotectonic is excellent medium for rising up emanation to the subsurface layer, is shown on the map. The tectonic zone of Liscie udolie in Bratislava-Karlova Ves area has been clearly detected by profile radon survey (a v > 50 kBq/m 3 ). 2) At present, northern half of the area of Kosice in question was covered by radon survey. The low and medium radon risks have been observed here, while localities with high radon risk are small in extent. The part of radon risk and soil permeability map from northern Kosice area is shown. (J.K.) 3 figs., 2 refs

  17. Use of polar and nonpolar fractions as additional information sources for studying thermoxidized virgin olive oils by FTIR

    Directory of Open Access Journals (Sweden)

    Tena, N.

    2014-09-01

    Full Text Available Fourier transform infrared (FTIR spectroscopy has been proposed to study the degradation of virgin olive oils (VOO in samples undergoing thermoxidation. The polar and nonpolar fractions of oxidized oils have been analyzed by FTIR to provide further information on the minor spectral changes taking place during thermoxidation. This information assists in the interpretation of the spectra of the samples. For this purpose polar and nonpolar fractions of 47 VOO samples thermoxidized (190 °C in a fryer were analyzed by FTIR. The time-course change of the band area assigned to single cis double bonds was explained by their correlation with the decrease in oleic acid (adjusted-R2=0.93. The bands assigned to the hydroxyl groups and the first overtone of ester groups was better studied in the spectra collected for the polar and nonpolar fractions, respectively. The bands assigned to peroxide, epoxy, tertiary alcohols and fatty acids were clearly observed in the spectra of the polar fraction while they are not noticeable in the spectra of the oils.La espectroscopía de infrarrojos por transformada de Fourier (FTIR se ha propuesto para estudiar la degradación de los aceites de oliva vírgenes (AOV sujetas a termoxidación. Las fracciones polares y no polares de aceites oxidados se analizaron mediante FTIR para obtener más información sobre los cambios espectrales menores que tienen lugar durante la termoxidación. Esa información ayuda en la interpretación de los espectros de las muestras puras. Con este objetivo, fracciones polares y no polares de 47 AOV termoxidados (190 °C en una freidora se analizaron mediante FTIR. La banda asignada a dobles enlaces cis se explica por su correlación con la disminución de ácido oleico (R2-ajustado=0,93. Las bandas asignadas a los grupos hidroxilos y del primer sobretono de los grupos éster se estudió mejor en los espectros recogidos para la fracción polar y no polar, respectivamente. Grupos asignados a per

  18. Creating Two-Dimensional Electron Gas in Nonpolar/Nonpolar Oxide Interface via Polarization Discontinuity: First-Principles Analysis of CaZrO3/SrTiO3 Heterostructure.

    Science.gov (United States)

    Nazir, Safdar; Cheng, Jianli; Yang, Kesong

    2016-01-13

    We studied strain-induced polarization and resulting conductivity in the nonpolar/nonpolar CaZrO3/SrTiO3 (CZO/STO) heterostructure (HS) system by means of first-principles electronic structure calculations. By modeling four types of CZO/STO HS-based slab systems, i.e., TiO2/CaO and SrO/ZrO2 interface models with CaO and ZrO2 surface terminations in each model separately, we found that the lattice-mismatch-induced compressive strain leads to a strong polarization in the CZO film and that as the CZO film thickness increases there exists an insulator-to-metal transition. The polarization direction and critical thickness of the CZO film for forming interfacial metallic states depend on the surface termination of CZO film in both types of interface models. In the TiO2/CaO and SrO/ZrO2 interface models with CaO surface termination, the strong polarization drives the charge transfer from the CZO film to the first few TiO2 layers in the STO substrate, leading to the formation of two-dimensional electron gas (2DEG) at the interface. In the HS models with ZrO2 surface termination, two polarization domains with opposite directions are in the CZO film, which results in the charge transfer from the middle CZO layer to the interface and surface, respectively, leading to the coexistence of the 2DEG on the interface and the two-dimensional hole gas (2DHG) at the middle CZO layer. These findings open a new avenue to achieve 2DEG (2DHG) in perovskite-based HS systems via polarization discontinuity.

  19. Prediction of non-polar gas solubilities in water, alcohols and aqueous alcohol solutions by the modified ASOG method

    Energy Technology Data Exchange (ETDEWEB)

    Tochigi, K.; Kojima, K.

    1982-07-01

    This study evaluated a technique for predicting gas solubilities based on a modified ASOG group-contribution method, considering water, alcohols, and aqueous alcohol solutions as the solvents. The nonpolar gaseous solutes considered were oxygen, nitrogen, hydrogen, carbon dioxide, argon, methane, ethane, ethylene, propane, and butane. Gas solubilities were correlated and predicted for a partial gas pressure of 1 atm and a temperature range of 50/sup 0/-100/sup 0/F (10/sup 0/-40/sup 0/C) in pure solvents, and then predicted for the same pressure and temperature range in mixed solvents using only the solubility data for the pure solvents. The deviations between the observed and predicted solubilities averaged 6.0% in pure systems and 10.2% in mixed solvents.

  20. Critical thickness for the formation of misfit dislocations originating from prismatic slip in semipolar and nonpolar III-nitride heterostructures

    KAUST Repository

    Smirnov, A. M.

    2016-01-20

    We calculate the critical thickness for misfit dislocation (MD) formation in lattice mismatched semipolar and nonpolar III-nitride wurtzite semiconductor layers for the case of MDs originated from prismatic slip (PSMDs). It has been shown that there is a switch of stress relaxation modes from generation of basal slip originated MDs to PSMDs after the angle between c-axis in wurtzite crystal structure and the direction of semipolar growth reaches a particular value, e.g., ∼70° for Al0.13Ga0.87N/GaN (h0h̄ 1) semipolar heterostructures. This means that for some semipolar growth orientations of III-nitride heterostructures biaxial relaxation of misfit stress can be realized. The results of modeling are compared to experimental data on the onset of plastic relaxation in AlxGa1−xN/GaN heterostructures.

  1. Determination of basicity of neutral organic phosphorus extractants in nonpolar solvents by the 31P NMR method

    International Nuclear Information System (INIS)

    Yakshin, V.V.; Meshcheryakov, N.M.; Il'in, E.G.; Ignatov, M.E.; Laskorin, B.N.

    1984-01-01

    The variant of the NMR method application is developed for quantitative description of acidic-basic properties of neutral organic phosphorus extractants, R 3 P--O (NPE), in non-polar organic solvents. For the NPE basicity determination the dependence of the chemical shift value in NMR 31 P spectra of 0.1 M NPE solutions in the dodecane on sulfuric acid acitivity in aqueous phase at 0-12 M acidity is studied. The linear equation relating NPE basicity and electronic structure of these compounds expressed through the sum: of Kabachnik reaction constants is derived. Linear dependences between the NPE basicity value in dodecane and NPE basicity in nitromethane as well as enthalpies of complexes formation with charge transport with standard acid-iodine in heptane, enthalpies of hydrogen complexes formation with phenol and water have been found

  2. Basal-plane stacking faults in non-polar GaN studied by off-axis electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lewis Z-Y; Rao, D V Sridhara; Kappers, M J; Humphreys, C J [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Geiger, D, E-mail: ZL249@cam.ac.u [Triebenberg Laboratory, Institute for Structure Physics, Technische Universitaet Dresden, D-01062 Dresden (Germany)

    2010-02-01

    We have studied basal-plane stacking faults in a non-polar (11-20) GaN epilayer using high-resolution electron microscopy and off-axis electron holography. The microstructure of the basal-plane stacking faults (BSFs) has been determined to be I{sub 1} type from high-resolution TEM images. High-resolution holograms along the [11-20] zone axis were obtained by off-axis electron holography on a Cs-corrected TEM, providing {approx}2 A spatial resolution in the reconstructed amplitude and phase images. Phase fluctuations across the stacking faults were detected, suggesting the presence of a built-in electric field. The uncertainties in the experiments and their interpretation are discussed.

  3. Measuring polarization dependent dispersion of non-polarizing beam splitter cubes with spectrally resolved white light interferometry

    Science.gov (United States)

    Csonti, K.; Hanyecz, V.; Mészáros, G.; Kovács, A. P.

    2017-06-01

    In this work we have measured the group-delay dispersion of an empty Michelson interferometer for s- and p-polarized light beams applying two different non-polarizing beam splitter cubes. The interference pattern appearing at the output of the interferometer was resolved with two different spectrometers. It was found that the group-delay dispersion of the empty interferometer depended on the polarization directions in case of both beam splitter cubes. The results were checked by inserting a glass plate in the sample arm of the interferometer and similar difference was obtained for the two polarization directions. These results show that to reach high precision, linearly polarized white light beam should be used and the residual dispersion of the empty interferometer should be measured at both polarization directions.

  4. Effect of asymmetrical transfer coefficients of a non-polarizing beam splitter on the nonlinear error of the polarization interferometer

    Science.gov (United States)

    Zhao, Chen-Guang; Tan, Jiu-Bin; Liu, Tao

    2010-09-01

    The mechanism of a non-polarizing beam splitter (NPBS) with asymmetrical transfer coefficients causing the rotation of polarization direction is explained in principle, and the measurement nonlinear error caused by NPBS is analyzed based on Jones matrix theory. Theoretical calculations show that the nonlinear error changes periodically, and the error period and peak values increase with the deviation between transmissivities of p-polarization and s-polarization states. When the transmissivity of p-polarization is 53% and that of s-polarization is 48%, the maximum error reaches 2.7 nm. The imperfection of NPBS is one of the main error sources in simultaneous phase-shifting polarization interferometer, and its influence can not be neglected in the nanoscale ultra-precision measurement.

  5. Direct Detection of the Ion Pair to Free Ions Transformation upon Complexation with an Ion Receptor in Non-Polar Solvents by using Conductometry.

    Science.gov (United States)

    Iseda, Kazuya; Kokado, Kenta; Sada, Kazuki

    2018-03-01

    In this study, we performed conductometry in various organic solvents to directly detect the transformation from tetrabutylammonium chloride ( TBACl ) ion-pair salt to the free ions through complexation with meso -octamethylcalix[4]pyrrole ( CP ), which is a well-known receptor for chloride anions. In the presence of CP , the conductivity of TBACl increases in various non-polar solvents, indicating that complexation with CP enhances the ionic dissociation of TBACl in such non-polar solvents. In other words, CP recognizes chloride as an ion-paired salt as well as a free anion in non-polar solvents. Additionally, the TBA(CP - Cl ) complex exhibited a considerably lower ion-pairing constant ( K ip ) than TBACl in non-polar solvents, resulting in enhanced conductivity. Based on these findings, we can conclude that complexation of an anion with a hydrophobic anion receptor will be useful for creating functional and stimuli-responsive soft materials in organic solvents using coulombic forces.

  6. Study of excess carrier dynamics in polar, semi-polar, and non-polar (In,Ga)N epilayers and QWs

    Energy Technology Data Exchange (ETDEWEB)

    Aleksiejunas, R. [Institute of Applied Research, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania); Laser Research Center, Vilnius University, Sauletekio Ave. 10, 10222 Vilnius (Lithuania); Lubys, L.; Jarasiunas, K. [Institute of Applied Research, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania); Vengris, M. [Laser Research Center, Vilnius University, Sauletekio Ave. 10, 10222 Vilnius (Lithuania); Wernicke, T.; Hoffmann, V.; Netzel, C.; Knauer, A.; Weyers, M. [Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12498 Berlin (Germany); Kneissl, M. [Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12498 Berlin (Germany); Institute of Solid State Physics, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany)

    2011-07-15

    We studied carrier recombination and diffusion in GaN/sapphire templates, (In,Ga)N layers, and (In,Ga)N quantum well structures oriented along the polar [0001], semi-polar [11-22], and non-polar [11-20] orientations by means of light induced transient grating, differential transmission, and photoluminescence optical techniques. We show that the lifetime of excess carriers drops by orders of magnitude when changing the orientation from polar to non-polar, both in GaN templates and (In,Ga)N layers. We attribute the shorter lifetime to carrier trapping by extended structural defects that are more abundant in non-polar grown samples. In addition, we observe pronounced carrier localization effects in the semi- and non-polar layers. We show that thick (In,Ga)N layers inherit the properties of the GaN templates. However, the thin quantum well structures show a lower carrier trapping activity. So, a better electrical quality can be assumed as compared to the thick (In,Ga)N layers. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Determination of inorganic arsenic in algae using bromine halogenation and on-line nonpolar solid phase extraction followed by hydride generation atomic flourescence spectrometry

    Science.gov (United States)

    Accurate, stable and fast analysis of toxic inorganic arsenic (iAs) in complicated and arsenosugar-rich algae matrix is always a challenge. Herein, a novel analytical method for iAs in algae was reported, using bromine halogenation and on-line nonpolar solid phase extraction (SPE) followed by hydrid...

  8. Ab initio density functional theory study of non-polar (10-10), (11-20) and semipolar {20-21} GaN surfaces

    Czech Academy of Sciences Publication Activity Database

    Mutombo, Pingo; Romanyuk, Olexandr

    2014-01-01

    Roč. 115, č. 20 (2014), "203508-1"-"203508-5" ISSN 0021-8979 Grant - others:AVČR(CZ) M100101201 Institutional support: RVO:68378271 Keywords : non-polar GaN * semipolar GaN * surface reconstructions * DFT Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2014

  9. An on-line normal-phase high performance liquid chromatography method for the rapid detection of radical scavengers in non-polar food matrixes

    NARCIS (Netherlands)

    Zhang, Q.; Klift, van der E.J.C.; Janssen, H.G.; Beek, van T.A.

    2009-01-01

    An on-line method for the rapid pinpointing of radical scavengers in non-polar mixtures like vegetable oils was developed. To avoid problems with dissolving the sample, normal-phase chromatography on bare silica gel was used with mixtures of hexane and methyl tert-butyl ether as the eluent. The high

  10. Concept medium program

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    2003-01-01

    The present essays is an attempt to dertermine the architecural project of the 21st century in realation to a modern conception of space as the medium of architecture, and of society as its program. This attempt adopts the internal point of view of an architect in describing a modern architectural...... project within the framework: concept - program, these notions being concieved as spatial representations primarily and immediately "given" to architecture....

  11. Raman spectra from very concentrated aqueous NaOH and from wet and dry, solid, and anhydrous molten, LiOH, NaOH, and KOH.

    Science.gov (United States)

    Walrafen, George E; Douglas, Rudolph T W

    2006-03-21

    High-temperature, high-pressure Raman spectra were obtained from aqueous NaOH solutions up to 2NaOHH2O, with X(NaOH)=0.667 at 480 K. The spectra corresponding to the highest compositions, X(NaOH)> or =0.5, are dominated by H3O2-. An IR xi-function dispersion curve for aqueous NaOH, at 473 K and 1 kbar, calculated from the data of Franck and Charuel indicates that the OH- ion forms H3O2- by preferential H bonding with nonhydrogen-bonded OH groups. Raman spectra from wet to anhydrous, solid LiOH, NaOH, and KOH yield sharp, symmetric OH- stretching peaks at 3664, 3633, and 3596 cm(-1), respectively, plus water-related, i.e., H3O2-, peaks near LiOH, 3562 cm(-1), NaOH, 3596 cm(-1), and, KOH, 3500 cm(-1). Absence of H3O2- peaks from the solid assures that the corresponding melt is anhydrous. Raman spectra from the anhydrous melts yield OH- stretching peak frequencies: LiOH, 3614+/-4 cm(-1), 873 K; NaOH, 3610+/-2 cm(-1), 975 K; and, KOH, 3607+/-2 cm(-1), 773 K, but low-frequency asymmetry due to ion-pair interactions is present which is centered near 3550 cm(-1). The ion-pair-related asymmetry corresponds to the sole IR maximum near 3550 cm(-1) from anhydrous molten NaOH, at 623 K. Bose-Einstein correction of published low-frequency Raman data from molten LiOH revealed an acoustic phonon, near 205 cm(-1), related to restricted translation of OH- versus Li+, and an optical phonon, at 625 cm(-1) and tau approximately 0.05 ps, due to protonic precession and/or pendular motion. Strong H bonding between water and the O atom of OH- forms H3O2-, but the proton of OH- does not bond with H significantly. Large Raman bandwidths (aqueous solutions) are explained in terms of inhomogeneous broadening due to proton transfer in a double well. Vibrational assignments are presented for H3O2-.

  12. Growth and characterization of nonpolar (10-10) ZnO transparent conductive oxide on semipolar (11–22) GaN-based light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki-Wook; Choi, Nak-Jung [Department of Nano-Optical Engineering, Korea Polytechnic University, Siheung, Gyeonggi-do, 429-839 (Korea, Republic of); Kim, Kyoung-Bo [Department of Metallurgical and Materials Engineering, Inha Technical College, Incheon, 402-752 (Korea, Republic of); Kim, Moojin [Department of Renewable Energy, Jungwon University, 85, Munmu-ro, Goesan-eup, Goesan-gun, Chungbuk, 367-805 (Korea, Republic of); Lee, Sung-Nam, E-mail: snlee@kpu.ac.kr [Department of Nano-Optical Engineering, Korea Polytechnic University, Siheung, Gyeonggi-do, 429-839 (Korea, Republic of)

    2016-05-05

    We have grown thin films of nonpolar m-plane (10-10) ZnO on a semipolar (11–22) GaN template by atomic layer deposition (ALD) at low growth temperatures (<200 °C). The surface morphology of the ZnO film is found to be an arrowhead-like structure, which is a typical surface structure of the semipolar (11–22) GaN films. On increasing the growth temperature of the ZnO films, the concentration and mobility of the charge carriers in the ZnO film are increased. However, the optical transmittance decreases with an increase in the growth temperature. Based on these results, we have fabricated semipolar (11–22) GaN-based light-emitting diodes (LEDs) with nonpolar m-plane ZnO film as a transparent conductive oxide (TCO) to improve the light extraction efficiency. In spite of a decrease in the optical transmittance, the operation voltage of semipolar (11–22) GaN-based LEDs is found to decrease with an increase in the growth temperature, which might be due to the improvements in the electrical properties and current spreading effect, resulting in an increase in the optical output power. - Highlights: • Polarity control of ZnO film grown in m-/c-sapphire and semipolar GaN template. • Achievement of high quality nonpolar m-plane ZnO flims on semipolar (11–22) GaN template. • The simultaneous improvements of carrier concentration and mobility in the nonpolar ZnO TCO flims. • Nonpolar ZnO TCO increases current spreading length and light output power of semipolar GaN-LED.

  13. Influence of Nonpolar Substances on the Extraction Efficiency of Six Alkaloids in Zoagumhwan Investigated by Ultra Performance Liquid Chromatography and Photodiode Array Detection

    Directory of Open Access Journals (Sweden)

    Shijing Liu

    2012-11-01

    Full Text Available A reverse phase ultra performance liquid chromatography and photodiode array (UPLC-PDA detection method was established for the determination of six alkaloids in Zoagumhwan (ZGW, and further for investigating the influence of nonpolar substances on the extraction efficiency of these alkaloids. The method was based on a BEH C18 (50 mm × 2.1 mm, 1.7 μm column and mobile phase of aqueous phosphoric acid and acetonitrile including 0.05% buffer solution under gradient elution. ZGW samples of ZGW I, II, III and IV were obtained and prepared by pre-processing the crude materials of Coptidis rhizoma and Evodiae fructus using four technologies, namely direct water decoction, removal of nonpolar substances in Evodiae fructus by supercritical fluid extraction (SFE, removal of nonpolar substances in ZGW by SFE and removal of nonpolar substances in ZGW by steam distillation. The developed and validated UPLC-PDA method was precise, accurate and sensitive enough based on the facts that the six alkaloids showed good regression (r > 0.9998, the limit of detections and quantifications for six alkaloids were less than 28.8 and 94.5 ng/mL, respectively, and the recovery was in the range of 98.56%–103.24%. The sequence of the total contents of six alkaloids in these samples was ZGW II > ZGW IV > ZGW III > ZGW I. ZGW II, in which nonpolar substances, including essential oils, were firstly removed from Evodiae fructus by SFE, had the highest content of the total alkaloids, indicating that extraction efficiency of the total alkaloids could be remarkably increased after Evodiae fructus being extracted by SFE.

  14. Polar and Nonpolar Gallium Nitride and Zinc Oxide based thin film heterostructures Integrated with Sapphire and Silicon

    Science.gov (United States)

    Gupta, Pranav

    This dissertation work explores the understanding of the relaxation and integration of polar and non-polar of GaN and ZnO thin films with Sapphire and silicon substrates. Strain management and epitaxial analysis has been performed on wurtzitic GaN(0001) thin films grown on c-Sapphire and wurtzitic non-polar a-plane GaN(11-20) thin films grown on r-plane Sapphire (10-12) by remote plasma atomic nitrogen source assisted UHV Pulsed Laser Deposition process. It has been established that high-quality 2-dimensional c-axis GaN(0001) nucleation layers can be grown on c-Sapphire by PLD process at growth temperatures as low as ˜650°C. Whereas the c-axis GaN on c-sapphire has biaxially negative misfit, the crystalline anisotropy of the a-plane GaN films on r-Sapphire results in compressive and tensile misfits in the two major orthogonal directions. The measured strains have been analyzed in detail by X-ray, Raman spectroscopy and TEM. Strain relaxation in GaN(0001)/Sapphire thin film heterostructure has been explained by the principle of domain matched epitaxial growth in large planar misfit system and has been demonstrated by TEM study. An attempt has been made to qualitatively understand the minimization of free energy of the system from the strain perspective. Analysis has been presented to quantify the strain components responsible for the compressive strain observed in the GaN(0001) thin films on c-axis Sapphire substrates. It was also observed that gallium rich deposition conditions in PLD process lead to smoother nucleation layers because of higher ad-atom mobility of gallium. We demonstrate near strain relaxed epitaxial (0001) GaN thin films grown on (111) Si substrates using TiN as intermediate buffer layer by remote nitrogen plasma assisted UHV pulsed laser deposition (PLD). Because of large misfits between the TiN/GaN and TiN/Si systems the TIN buffer layer growth occurs via nucleation of interfacial dislocations under domain matching epitaxy paradigm. X-ray and

  15. Ringwoodite growth rates from olivine with ~75 ppmw H2O: Metastable olivine must be nearly anhydrous to exist in the mantle transition zone

    Energy Technology Data Exchange (ETDEWEB)

    Du Frane, Wyatt L. [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration; Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Atmospheric, Earth and Energy Division; Sharp, Thomas G. [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration; Mosenfelder, Jed L. [California Inst. of Technology (CalTech), Pasadena, CA (United States). Division of Geological and Planetary Sciences; Leinenweber, Kurt [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration

    2013-04-15

    It has been previously demonstrated that as little as 300 ppmw H2O increases wadsleyite and ringwoodite growth rates to magnitudes that are inconsistent with the metastable olivine hypothesis. To further test this hypothesis, we present new ringwoodite growth rate measurements from olivine with ~75 ppmw H2O at 18 GPa and 700, 900, and 1100 °C. These growth rates are nearly identical to those from olivine with ~300 ppmw H2O, and significantly higher than those from nominally anhydrous olivine. We infer that transformation of olivine with 75-300 ppmw H2O is primarily enhanced by hydrolytic weakening of reaction rims, which reduces the elastic strain-energy barrier to growth. We present a new method for fitting nonlinear nominally anhydrous data, to demonstrate that reduction of growth rates by elastic strain energy is an additional requirement for metastable olivine. In conclusion, based on previous thermokinetic modeling, these enhanced growth rates are inconsistent with the persistence of metastable olivine wedges into the mantle transition zone. Metastable persistence of olivine into the mantle transition-zone would therefore require < 75 ppmw H2O.

  16. A structural phase transition coupled to the Fe{sup 3+} spin-state crossover in anhydrous RbMn[Fe(CN){sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Rykov, A. I., E-mail: rykov3@yahoo.com; Wang, J., E-mail: wangjh@dicp.ac.cn; Zhang, T. [Chinese Academy of Sciences, Moessbauer Effect Data Center, Dalian Institute of Chemical Physics (China); Nomura, K. [University of Tokyo, Graduate School of Engineering (Japan)

    2013-04-15

    Linkage isomerism is the coexistence of iso-compositional molecules or solids differing by connectivity of the metal to a ligand. In a crystalline solid state, the rotation is possible for asymmetric ligands, e.g., for cyanide ligand. Here we report on our observation of a phase transition in anhydrous RbMn[Fe(CN){sub 6}] (nearly stoichiometric) and on the effect of linkage isomerism ensuing our interpretation of the results of Moessbauer study in which we observe the iron spin state crossover among two phases involved into this transition. The anhydrous RbMn[Fe(CN){sub 6}] can be prepared via prolonged thermal treatment (1 week at at 80 Degree-Sign C) of the as-synthesized hydrated RbMn[Fe(CN){sub 6}]{center_dot}H{sub 2}O. The latter compound famous for its charge-transfer phase transition is a precursor in our case. As the temperature is raising above 80 Degree-Sign C (remaining below 100 Degree-Sign C) we observe RbMn[Fe(CN){sub 6}] that inherited its F-43 m symmetry from RbMn[Fe(CN){sub 6}]{center_dot}H{sub 2}O transforming to a phase of the Fm-3 m symmetry. In the latter, more than half of Fe{sup 3 + } ions are in high-spin state. We suggest a plausible way to explain the spin-crossover that is to allow the linkage isomerism by rotation of the cyanide ligands.

  17. DENSE MEDIUM CYCLONE OPTIMIZATON

    Energy Technology Data Exchange (ETDEWEB)

    Gerald H. Luttrell; Chris J. Barbee; Peter J. Bethell; Chris J. Wood

    2005-06-30

    Dense medium cyclones (DMCs) are known to be efficient, high-tonnage devices suitable for upgrading particles in the 50 to 0.5 mm size range. This versatile separator, which uses centrifugal forces to enhance the separation of fine particles that cannot be upgraded in static dense medium separators, can be found in most modern coal plants and in a variety of mineral plants treating iron ore, dolomite, diamonds, potash and lead-zinc ores. Due to the high tonnage, a small increase in DMC efficiency can have a large impact on plant profitability. Unfortunately, the knowledge base required to properly design and operate DMCs has been seriously eroded during the past several decades. In an attempt to correct this problem, a set of engineering tools have been developed to allow producers to improve the efficiency of their DMC circuits. These tools include (1) low-cost density tracers that can be used by plant operators to rapidly assess DMC performance, (2) mathematical process models that can be used to predict the influence of changes in operating and design variables on DMC performance, and (3) an expert advisor system that provides plant operators with a user-friendly interface for evaluating, optimizing and trouble-shooting DMC circuits. The field data required to develop these tools was collected by conducting detailed sampling and evaluation programs at several industrial plant sites. These data were used to demonstrate the technical, economic and environmental benefits that can be realized through the application of these engineering tools.

  18. Computation as Medium

    DEFF Research Database (Denmark)

    Jochum, Elizabeth Ann; Putnam, Lance

    2017-01-01

    Artists increasingly utilize computational tools to generate art works. Computational approaches to art making open up new ways of thinking about agency in interactive art because they invite participation and allow for unpredictable outcomes. Computational art is closely linked...... to the participatory turn in visual art, wherein spectators physically participate in visual art works. Unlike purely physical methods of interaction, computer assisted interactivity affords artists and spectators more nuanced control of artistic outcomes. Interactive art brings together human bodies, computer code......, and nonliving objects to create emergent art works. Computation is more than just a tool for artists, it is a medium for investigating new aesthetic possibilities for choreography and composition. We illustrate this potential through two artistic projects: an improvisational dance performance between a human...

  19. Spiegel. Medium. Kunst

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    of this kind as the marks of a meta-complex of method out of which new models of the image continually arise. The waxing intangibility of proliferating images be they of the mind, in dreams, through gestures, and the equally rampant growth of microstructuring in allocations of knowledge lay a challenge before...... to research. As a void in the apprehension of the world, the mirror obtained a scholarly perspective and the more so in areas beyond its own qualities as a medium, i.e. in images and metaphor, the paradigms of all research looking to image and text. This investigation sets out to comprehend paradoxes......, and space (albeit no expanse) is there to consider the methodological pros and cons of such a selective approach. Even in this synopsis, it has to be and can be stated that what makes for the affinities between psychological, literary and image-research approaches in research on the mirror is the shared...

  20. The diffuse interstellar medium

    Science.gov (United States)

    Cox, Donald P.

    1990-01-01

    The last 20 years of the efforts to understand the diffuse ISM are reviewed, with recent changes of fundamental aspects being highlighted. Attention is given to the interstellar pressure and its components, the weight of the ISM, the midplane pressure contributions, and pressure contributions at 1 kpc. What velocity dispersions, cosmic ray pressure, and magnetic field pressure that can be expected for a gas in a high magnetic field environment is addressed. The intercloud medium is described, with reference to the work of Cox and Slavin (1989). Various caveats are discussed and a number of areas for future investigation are identified. Steps that could be taken toward a successful phase segregation model are discussed.

  1. Resolving the false-negative issues of the nonpolar organic amendment in whole-sediment toxicity identification evaluations.

    Science.gov (United States)

    Mehler, W Tyler; Keough, Michael J; Pettigrove, Vincent

    2018-04-01

    Three common false-negative scenarios have been encountered with amendment addition in whole-sediment toxicity identification evaluations (TIEs): dilution of toxicity by amendment addition (i.e., not toxic enough), not enough amendment present to reduce toxicity (i.e., too toxic), and the amendment itself elicits a toxic response (i.e., secondary amendment effect). One such amendment in which all 3 types of false-negatives have been observed is with the nonpolar organic amendment (activated carbon or powdered coconut charcoal). The objective of the present study was to reduce the likelihood of encountering false-negatives with this amendment and to increase the value of the whole-sediment TIE bioassay. To do this, the present study evaluated the effects of various activated carbon additions to survival, growth, emergence, and mean development rate of Chironomus tepperi. Using this information, an alternative method for this amendment was developed which utilized a combination of multiple amendment addition ratios based on wet weight (1%, lower likelihood of the secondary amendment effect; 5%, higher reduction of contaminant) and nonconventional endpoints (emergence, mean development rate). This alternative method was then validated in the laboratory (using spiked sediments) and with contaminated field sediments. Using these multiple activated carbon ratios in combination with additional endpoints (namely, emergence) reduced the likelihood of all 3 types of false-negatives and provided a more sensitive evaluation of risk. Environ Toxicol Chem 2018;37:1219-1230. © 2017 SETAC. © 2017 SETAC.

  2. Human Cytotoxic T Lymphocytes Form Dysfunctional Immune Synapses with B Cells Characterized by Non-Polarized Lytic Granule Release

    Directory of Open Access Journals (Sweden)

    Anna Kabanova

    2016-04-01

    Full Text Available Suppression of the cytotoxic T cell (CTL immune response has been proposed as one mechanism for immune evasion in cancer. In this study, we have explored the underlying basis for CTL suppression in the context of B cell malignancies. We document that human B cells have an intrinsic ability to resist killing by freshly isolated cytotoxic T cells (CTLs, but are susceptible to lysis by IL-2 activated CTL blasts and CTLs isolated from immunotherapy-treated patients with chronic lymphocytic leukemia (CLL. Impaired killing was associated with the formation of dysfunctional non-lytic immune synapses characterized by the presence of defective linker for activation of T cells (LAT signaling and non-polarized release of the lytic granules transported by ADP-ribosylation factor-like protein 8 (Arl8. We propose that non-lytic degranulation of CTLs are a key regulatory mechanism of evasion through which B cells may interfere with the formation of functional immune synapses by CTLs.

  3. Tip-induced domain growth on the non-polar cuts of lithium niobate single-crystals

    Science.gov (United States)

    Alikin, D. O.; Ievlev, A. V.; Turygin, A. P.; Lobov, A. I.; Kalinin, S. V.; Shur, V. Ya.

    2015-05-01

    Currently, ferroelectric materials with designed domain structures are considered as a perspective material for new generation of photonic, data storage, and data processing devices. Application of external electric field is the most convenient way of the domain structure formation. Lots of papers are devoted to the investigation of domain kinetics on polar surface of crystals while the forward growth remains one of the most mysterious stages due to lack of experimental methods allowing to study it. Here, we performed tip-induced polarization reversal on X- and Y-non-polar cuts in single-crystal of congruent lithium niobate which allows us to study the forward growth with high spatial resolution. The revealed difference in the shape and length of domains induced on X- and Y-cuts is beyond previously developed theoretical approaches used for the theoretical consideration of the domains growth at non-polar ferroelectric surfaces. To explain experimental results, we used kinetic approach with anisotropy of screening efficiency along different crystallographic directions.

  4. On flotation separation of oxo-anions of transition metals by the use of fine-emulsified solutions of cationic collector in non-polar liquids

    International Nuclear Information System (INIS)

    Skrylev, L.D.; Purich, A.N.; Babinets, S.K.

    1980-01-01

    Experimentally shown is a principle possibility of flotation separation of oxo-anions of transition metals by the use of fine-emulsified solutions of cationic collector in non-polar liquids. Ammonium vanadate and sodium tuno.state solutions have been the objects of study. Hexadezilamine has been used as collector. The collector has been introduced in the form of hexadecylamine emulsions in n-decane, in tetrachloromethane or alcohol. Optimum pH value ranges are determined for separation processes

  5. Pseudocapacitive properties of nano-structured anhydrous ruthenium oxide thin film prepared by electrostatic spray deposition and electrochemical lithiation/delithiation

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.H.; Kim, J.Y.; Kim, K.B. [Division of Materials Science and Engineering, Yonsei University, Seoul (Korea, Republic of)

    2010-10-15

    Nano-structured anhydrous ruthenium oxide (RuO{sub 2}) thin films were prepared using an electrostatic spray deposition (ESD) technique followed by electrochemical lithiation and delithiation. During the electrochemical lithiation process, RuO{sub 2} decomposed to nano-structured metallic ruthenium Ru with the concomitant formation of Li{sub 2}O. Nano-structured RuO{sub 2} was formed upon subsequent electrochemical extraction of Li from the Ru/Li{sub 2}O nanocomposite. Electrochemical lithiation/deliathiation at different charge/discharge rates (C-rate) was used to control the nano-structure of the anhydrous RuO{sub 2}. Electrochemical lithiation/delithiation of the RuO{sub 2} thin film electrode at different C-rates was closely related to the specific capacitance and high rate capability of the nano-structured anhydrous RuO{sub 2} thin film. Nano-structured RuO{sub 2} thin films prepared by electrochemical lithiation and delithiation at 2C rate showed the highest specific capacitance of 653 F g{sup -1} at 20 mV s{sup -1}, which is more than two times higher than the specific capacitance of 269 F g{sup -1} for the as-prepared RuO{sub 2}. In addition, it showed 14% loss in specific capacitance from 653 F g{sup -1} at 20 mV s{sup -1} to 559 F g{sup -1} at 200 mV s{sup -1}, indicating significant improvement in the high rate capability compared to the 26% loss of specific capacitance of the as-prepared RuO{sub 2} electrode from 269 F g{sup -1} at 20 mV s{sup -1} to 198 F g{sup -1} at 200 mV s{sup -1} for the same change in scan rate. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  6. Changes in the solid state of anhydrous and hydrated forms of sodium naproxen under different grinding and environmental conditions: Evidence of the formation of new hydrated forms.

    Science.gov (United States)

    Censi, Roberta; Rascioni, Riccardo; Di Martino, Piera

    2015-05-01

    The aim of the present work was to investigate the solid state change of the anhydrous and hydrate solid forms of sodium naproxen under different grinding and environmental conditions. Grinding was carried out manually in a mortar under the following conditions: at room temperature under air atmosphere (Method A), in the presence of liquid nitrogen under air atmosphere (Method B), at room temperature under nitrogen atmosphere (Method C), and in the presence of liquid nitrogen under nitrogen atmosphere (Method D). Among the hydrates, the following forms were used: a dihydrate form (DSN) obtained by exposing the anhydrous form at 55% RH; a dihydrate form (CSN) obtained by crystallizing sodium naproxen from water; the tetrahydrate form (TSN) obtained by exposing the anhydrous form at 75% RH. The metastable monohydrate form (MSN), previously described in the literature, was not used because of its high physical instability. The chemical stability during grinding was firstly assessed and proven by HPLC. Modification of the particle size and shape, and changes in the solid state under different grinding methods were evaluated by scanning electron microscopy, and X-ray powder diffractometry and thermogravimetry, respectively. The study demonstrated the strong influence of starting form, grinding and environmental conditions on particle size, shape and solid state of recovered sodium naproxen forms. In particular, it was demonstrated that in the absence of liquid nitrogen (Methods A and C), either at air or at nitrogen atmosphere, the monohydrate form (MSN) was obtained from any hydrates, meaning that these grinding conditions favored the dehydration of superior hydrates. The grinding process carried out in the presence of liquid nitrogen (Method B) led to further hydration of the starting materials: new hydrate forms were identified as one pentahydrate form and one hexahydrate form. The hydration was caused by the condensation of the atmospheric water on sodium naproxen

  7. Impact of band structure and transition matrix elements on polarization properties of the photoluminescence of semipolar and nonpolar InGaN quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Schade, L.; Schwarz, U.T. [Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79108 Freiburg (Germany); Fraunhofer Institute for Applied Solid State Physics (IAF), Tullastrasse 72, 79108 Freiburg (Germany); Wernicke, T. [Institute of Solid State Physics, Technical University, Hardenbergstrasse 36, 10623 Berlin (Germany); Weyers, M. [Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin (Germany); Kneissl, M. [Institute of Solid State Physics, Technical University, Hardenbergstrasse 36, 10623 Berlin (Germany); Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin (Germany)

    2011-03-15

    Partial or full linear polarization is characteristic for the spontaneous emission of light from semipolar and nonpolar InGaN quantum wells. This property is an implication of the crystalline anisotropy as a basic property of the wurtzite structure. The influence of this anisotropy on the band structure and the transition matrix elements was calculated by a k.p-method for arbitrary quantum well orientations with respect to the c-axis; results are shown here in detail. Optical polarization is a direct consequence of a broken symmetry, mainly affecting the transition matrix elements from the conduction to the valence bands. Furthermore, the strain of the InGaN quantum well strongly depends on the crystal orientation of the substrate, resulting in a valence band mixing. The composition of the eigenfunctions has emerged to be most important for the polarization dependence of strained semipolar and nonpolar InGaN QW. The matrix elements, in combination with the thermal occupation of the bands, determine the polarization of the spontaneously emitted light. Our photoluminescence measurements of nonpolar QW match well with this model. However, in contrast to calculations with standard band parameters, the two topmost subbands show a larger separation in the emitted energy. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Conversion of polar and non-polar algae oil lipids to fatty acid methyl esters with solid acid catalysts--A model compound study.

    Science.gov (United States)

    Asikainen, Martta; Munter, Tony; Linnekoski, Juha

    2015-09-01

    Bio-based fuels are becoming more and more important due to the depleting fossil resources. The production of biodiesel from algae oil is challenging compared to terrestrial vegetable oils, as algae oil consists of polar fatty acids, such as phospholipids and glycolipids, as well as non-polar triglycerides and free fatty acids common in vegetable oils. It is shown that a single sulphonated solid acid catalyst can perform the esterification and transesterification reactions of both polar and non-polar lipids. In mild reaction conditions (60-70 °C) Nafion NR50 catalyst produces methyl palmitate (FAME) from the palmitic acid derivatives of di-, and tri-glyceride, free fatty acid, and phospholipid with over 80% yields, with the glycolipid derivative giving nearly 40% yields of FAME. These results demonstrate how the polar and non-polar lipid derivatives of algal oil can be utilised as feedstocks for biodiesel production with a single catalyst in one reaction step. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Luminescence of highly excited nonpolar a-plane GaN and AlGaN/GaN multiple quantum wells

    International Nuclear Information System (INIS)

    Jursenas, S.; Kuokstis, E.; Miasojedovas, S.; Kurilcik, G.; Zukauskas, A.; Chen, C.Q.; Yang, J.W.; Adivarahan, V.; Asif Khan, M.

    2004-01-01

    Carrier recombination dynamics in polar and nonpolar GaN epilayers and GaN/AlGaN multiple quantum wells grown over sapphire substrates with a various crystallographic orientation were studied under high photoexcitation by 20 ps laser pulses. The transient luminescence featured a significant enhancement on nonradiative recombination of free carriers for nonpolar a-plane GaN epilayers compared to conventional c-plane samples. The epitaxial layer overgrowth technique was demonstrated to significantly improve the quality of nonpolar a-plane films. This was proved by more than 40-fold increase in luminescence decay time (430 ps compared to ≤ 10 ps in the ordinary a-plane epilayer). Under high-excitation regime, a complete screening of built-in electric field by free carriers in multiple quantum wells grown on c-plane and r-plane sapphire substrates was achieved. Under such high excitation, luminescence efficiency and carrier lifetime of multiple quantum wells were shown to be determined by the substrate quality. (author)

  10. Sign change in the net force in sphere-plate and sphere-sphere systems immersed in nonpolar critical fluid due to the interplay between the critical Casimir and dispersion van der Waals forces.

    Science.gov (United States)

    Valchev, Galin; Dantchev, Daniel

    2017-08-01

    We study systems in which both long-ranged van der Waals and critical Casimir interactions are present. The latter arise as an effective force between bodies when immersed in a near-critical medium, say a nonpolar one-component fluid or a binary liquid mixture. They are due to the fact that the presence of the bodies modifies the order parameter profile of the medium between them as well as the spectrum of its allowed fluctuations. We study the interplay between these forces, as well as the total force (TF) between a spherical colloid particle and a thick planar slab and between two spherical colloid particles. We do that using general scaling arguments and mean-field-type calculations utilizing the Derjaguin and the surface integration approaches. They both are based on data of the forces between two parallel slabs separated at a distance L from each other, confining the fluctuating fluid medium characterized by its temperature T and chemical potential μ. The surfaces of the colloid particles and the slab are coated by thin layers exerting strong preference to the liquid phase of the fluid, or one of the components of the mixture, modeled by strong adsorbing local surface potentials, ensuring the so-called (+,+) boundary conditions. On the other hand, the core region of the slab and the particles influence the fluid by long-ranged competing dispersion potentials. We demonstrate that for a suitable set of colloids-fluid, slab-fluid, and fluid-fluid coupling parameters, the competition between the effects due to the coatings and the core regions of the objects involved result, when one changes T, μ, or L, in sign change of the Casimir force (CF) and the TF acting between the colloid and the slab, as well as between the colloids. This can be used for governing the behavior of objects, say colloidal particles, at small distances, say in colloid suspensions for preventing flocculation. It can also provide a strategy for solving problems with handling, feeding

  11. Sign change in the net force in sphere-plate and sphere-sphere systems immersed in nonpolar critical fluid due to the interplay between the critical Casimir and dispersion van der Waals forces

    Science.gov (United States)

    Valchev, Galin; Dantchev, Daniel

    2017-08-01

    We study systems in which both long-ranged van der Waals and critical Casimir interactions are present. The latter arise as an effective force between bodies when immersed in a near-critical medium, say a nonpolar one-component fluid or a binary liquid mixture. They are due to the fact that the presence of the bodies modifies the order parameter profile of the medium between them as well as the spectrum of its allowed fluctuations. We study the interplay between these forces, as well as the total force (TF) between a spherical colloid particle and a thick planar slab and between two spherical colloid particles. We do that using general scaling arguments and mean-field-type calculations utilizing the Derjaguin and the surface integration approaches. They both are based on data of the forces between two parallel slabs separated at a distance L from each other, confining the fluctuating fluid medium characterized by its temperature T and chemical potential μ . The surfaces of the colloid particles and the slab are coated by thin layers exerting strong preference to the liquid phase of the fluid, or one of the components of the mixture, modeled by strong adsorbing local surface potentials, ensuring the so-called (+,+) boundary conditions. On the other hand, the core region of the slab and the particles influence the fluid by long-ranged competing dispersion potentials. We demonstrate that for a suitable set of colloids-fluid, slab-fluid, and fluid-fluid coupling parameters, the competition between the effects due to the coatings and the core regions of the objects involved result, when one changes T , μ , or L , in sign change of the Casimir force (CF) and the TF acting between the colloid and the slab, as well as between the colloids. This can be used for governing the behavior of objects, say colloidal particles, at small distances, say in colloid suspensions for preventing flocculation. It can also provide a strategy for solving problems with handling, feeding

  12. Polar and non-polar heterocyclic amines in cooked fish and meat products and their corresponding pan residues.

    Science.gov (United States)

    Skog, K; Augustsson, K; Steineck, G; Stenberg, M; Jägerstad, M

    1997-06-01

    Fourteen cooked dishes with their corresponding pan residues were analysed for polar and non-polar heterocyclic amines using HPLC. The choice of foods, including beef, pork, poultry, game, fish, egg and sausages, was based on an investigation of an elderly population in Stockholm participating in an analytical epidemiological case-control study on cancer risks after intake of heterocyclic amines. The food items were prepared using normal household cooking practices, and to reflect the wide range of surface browning of the cooked dishes that would be encountered in this population, four cooking temperatures were used in the range 150-225 degrees C. For all food samples, the total amount of heterocyclic amines formed at 150 degrees C was less than 1 ng/g cooked product, and at 175 degrees C less than 2 ng/g. The highest concentrations of heterocyclic amines were detected in fillet of pork, reindeer meat and chicken breast fried at 200 and 225 degrees C and their corresponding pan residues. The total sum of 2-amino-3,8-dimethylimidazo-[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine was about 1 microgram per 100 g portion (including pan residues) for reindeer meat and chicken breast, and between 1.9 and 6.3 micrograms per 100-g portion for fillet of pork. PhIP was the most abundant heterocyclic amine, identified in 73 of 84 samples, and the highest concentration of PhIP, 32.0 ng/g, was found in the pan residue from fillet of pork cooked at 225 degrees C. The non-polar heterocyclic amines 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and 3-amino-1-methyl-5H-pyrido[4,3-b]indole were detected in the range of 0.5-7.4 ng/g in most foods cooked at 225 degrees C, and also in meat sauce prepared at 200 and 175 degrees C. The other heterocyclic amines tested for: 2-amino-3-methylimidazo-[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-6-methyl-pyrido-[1,2-a:3',2'-d]-imidazole and 2

  13. Non-polar organic compounds in marine aerosols over the northern South China Sea: Influence of continental outflow.

    Science.gov (United States)

    Zhao, Yan; Zhang, Yingyi; Fu, Pingqing; Ho, Steven Sai Hang; Ho, Kin Fai; Liu, Fobang; Zou, Shichun; Wang, Shan; Lai, Senchao

    2016-06-01

    Filter samples of total suspended particle (TSP) collected during a cruise campaign over the northern South China Sea (SCS) from September to October 2013 were analyzed for non-polar organic compounds (NPOCs) as well as organic carbon (OC), elemental carbon (EC) and water-soluble ions. A total of 115 NPOCs species in groups of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), iso-/antiso-alkanes, hopanes, steranes, methylalkanes, branched alkanes, cycloalkanes, alkenes and phthalates were detected. The characteristics of NPOCs in marine TSP samples were investigated to understand the sources from the Asian continent and other regions. The concentrations of total NPOCs ranged from 19.8 to 288.2 ng/m(3) with an average of 87.9 ng/m(3), which accounted for 0.8-1.7% (average 1.0%) of organic matter (OM). n-Alkanes was the predominant group, accounting for 43.1-79.5%, followed by PAHs (5.5-44.4%) and hopanes (1.6-11.4%). We found that primary combustion (biomass burning/fossil fuel combustion) was the dominant source for the majority of NPOCs (89.1%). Biomass burning in southern/southeastern China via long-range transport was proposed to be a major contributor of NPOCs in marine aerosols over the northern SCS, suggested by the significant correlations between nss-K(+) and NPOCs groups as well as the analysis of air mass back-trajectory and fire spots. For the samples with strong continental influence, the strong enhancement in concentrations of n-alkanes, PAHs, hopanes and steranes were attributed to fossil fuel (coal/petroleum) combustion. In addition, terrestrial plants waxes were another contributor to NPOCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Smooth perfluorinated surfaces with different chemical and physical natures: their unusual dynamic dewetting behavior toward polar and nonpolar liquids.

    Science.gov (United States)

    Cheng, Dalton F; Masheder, Benjamin; Urata, Chihiro; Hozumi, Atsushi

    2013-09-10

    The effects of surface chemistry and the mobility of surface-tethered functional groups of various perfluorinated surfaces on their dewetting behavior toward polar (water) and nonpolar (n-hexadecane, n-dodecane, and n-decane) liquids were investigated. In this study, three types of common smooth perfluorinated surfaces, that is, a perfluoroalkylsilane (heptadecafluoro-1,1,2,2-tetrahydrooctyl-dimethylchlorosilane, FAS17) monomeric layer, an amorphous fluoropolymer film (Teflon AF 1600), and a perfluorinated polyether (PFPE)-terminated polymer brush film (Optool DSX), were prepared and their static/dynamic dewetting characteristics were compared. Although the apparent static contact angles (CAs) of these surfaces with all probe liquids were almost identical to each other, the ease of movement of liquid drops critically depended on the physical (solidlike or liquidlike) natures of the substrate surface. CA hysteresis and substrate tilt angles (TAs) of all probe liquids on the Optool DSX surface were found to be much lower than those of Teflon AF1600 and FAS17 surfaces due to its physical polymer chain mobility at room temperature and the resulting liquidlike nature. Only 6.0° of substrate incline was required to initiate movement for a small drop (5 μL) of n-decane, which was comparable to the reported substrate TA value (5.3°) for a superoleophobic surface (θ(S) > 160°, textured perfluorinated surface). Such unusual dynamic dewetting behavior of the Optool DSX surface was also markedly enhanced due to the significant increase in the chain mobility of PFPE by moderate heating (70 °C) of the surface, with substrate TA reducing to 3.0°. CA hysteresis and substrate TAs rather than static CAs were therefore determined to be of greater consequence for the estimation of the actual dynamic dewetting behavior of alkane probe liquids on these smooth perfluorinated surfaces. Their dynamic dewettability toward alkane liquids is in the order of Optool DSX > Teflon AF1600

  15. Antidiabetic, cytotoxic, antioxidant and antitrematodal medicinal efficacy of polar and non-polar phytochemicals of Balanites aegyptiaca Del.

    Directory of Open Access Journals (Sweden)

    Hanan Abd Al-Hay Saied Al-Ashaal

    2017-11-01

    Full Text Available Objective: To investigate the biological activities of polar and non-polar extracts of Balanites aegyptiaca fruits. Methods: Antihyperglycemic activity using alloxan induced diabetic rats was evaluated. In vitro cytotoxicity against human carcinoma cell lines activity in addition to antioxidant and antitrematodal effects were investigated. Phytochemicals were determined using chromatographic and spectral analyses including TLC, GC and LC/MS/MS methods. Results: The reduction in blood glucose level reached 64.13%, 69.07% and 77.01% for hexane, chloroform and methanol extract, respectively. Isolated organs and histopathological examination illustrated improvement in treated animal's pancreas which is the master gland in controlling glucose level. The highest in vitro free radical scavenging capacity was achieved by chloroform extract (75.72%. Meanwhile, hexane and methanol extracts exhibited 44.01% and 41.77% scavenging capacity, respectively. Cytotoxic activity against human carcinoma cell lines illustrated efficacious influence against brain, liver, lung, breast and lymphoblastic leukemia cell lines. Brain cell line was the most susceptible cell line by both chloroform and methanol extracts. In vitro antitrematodal effectiveness showed that 100% mortality of Schistosoma worms was induced at the 3rd and 5th days for methanol and chloroform extracts. Meanwhile, both extracts exhibited antifasciolosis activity with LC50 of 63.19 and 55.15 mg/L, respectively. Conclusions: The current results illustrated that Balanites aegyptiaca phytochemicals induced potent hypoglycemic activity and potent to moderate antioxidant and cytotoxic effects. Chloroform and methanol extracts were found to have antitrematodal efficacy against Schistosoma mansoni and Fasciola gigantica hepatic worms.

  16. Comparison of nonpolar III-nitride vertical-cavity surface-emitting lasers with tunnel junction and ITO intracavity contacts

    KAUST Repository

    Leonard, J. T.

    2016-03-01

    We report on the lasing of III-nitride nonpolar, violet, vertical-cavity surface-emitting lasers (VCSELs) with III-nitride tunnel-junction (TJ) intracavity contacts and ion implanted apertures (IIAs). The TJ VCSELs are compared to similar VCSELs with tin-doped indium oxide (ITO) intracavity contacts. Prior to analyzing device results, we consider the relative advantages of III-nitride TJs for blue and green emitting VCSELs. The TJs are shown to be most advantageous for violet and UV VCSELs, operating near or above the absorption edge for ITO, as they significantly reduce the total internal loss in the cavity. However, for longer wavelength III-nitride VCSELs, TJs primarily offer the advantage of improved cavity design flexibility, allowing one to make the p-side thicker using a thick n-type III-nitride TJ intracavity contact. This offers improved lateral current spreading and lower loss, compare to using ITO and p-GaN, respectively. These aspects are particularly important for achieving high-power CW VCSELs, making TJs the ideal intracavity contact for any III-nitride VCSEL. A brief overview of III-nitride TJ growth methods is also given, highlighting the molecular-beam epitaxy (MBE) technique used here. Following this overview, we compare 12 mu m aperture diameter, violet emitting, TJ and ITO VCSEL experimental results, which demonstrate the significant improvement in differential efficiency and peak power resulting from the reduced loss in the TJ design. Specifically, the TJ VCSEL shows a peak power of similar to 550 mu W with a threshold current density of similar to 3.5 kA/cm(2), while the ITO VCSELs show peak powers of similar to 80 mu W and threshold current densities of similar to 7 kA/cm

  17. A nonpolar, nonamphiphilic molecule can accelerate adsorption of phospholipids and lower their surface tension at the air/water interface.

    Science.gov (United States)

    Nguyen, Phuc Nghia; Trinh Dang, Thuan Thao; Waton, Gilles; Vandamme, Thierry; Krafft, Marie Pierre

    2011-10-04

    The adsorption dynamics of a series of phospholipids (PLs) at the interface between an aqueous solution or dispersion of the PL and a gas phase containing the nonpolar, nonamphiphilic linear perfluorocarbon perfluorohexane (PFH) was studied by bubble profile analysis tensiometry. The PLs investigated were dioctanoylphosphatidylcholine (DiC(8)-PC), dilaurylphosphatidylcholine, dimyristoylphosphatidylcholine, and dipalmitoylphosphatidylcholine. The gas phase consisted of air or air saturated with PFH. The perfluorocarbon gas was found to have an unexpected, strong effect on both the adsorption rate and the equilibrium interfacial tension (γ(eq)) of the PLs. First, for all of the PLs, and at all concentrations investigated, the γ(eq) values were significantly lower (by up to 10 mN m(-1)) when PFH was present in the gas phase. The efficacy of PFH in decreasing γ(eq) depends on the ability of PLs to form micelles or vesicles in water. For vesicles, it also depends on the gel or fluid state of the membranes. Second, the adsorption rates of all the PLs at the interface (as assessed by the time required for the initial interfacial tension to be reduced by 30%) are significantly accelerated (by up to fivefold) by the presence of PFH for the lower PL concentrations. Both the surface-tension reducing effect and the adsorption rate increasing effect establish that PFH has a strong interaction with the PL monolayer and acts as a cosurfactant at the interface, despite the absence of any amphiphilic character. Fitting the adsorption profiles of DiC(8)-PC at the PFH-saturated air/aqueous solution interface with the modified Frumkin model indicated that the PFH molecule lay horizontally at the interface. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Nonpolar III-nitride vertical-cavity surface-emitting laser with a photoelectrochemically etched air-gap aperture

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, J. T., E-mail: jtleona01@gmail.com; Yonkee, B. P.; Cohen, D. A.; Megalini, L.; Speck, J. S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Lee, S. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); DenBaars, S. P.; Nakamura, S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States)

    2016-01-18

    We demonstrate a III-nitride nonpolar vertical-cavity surface-emitting laser (VCSEL) with a photoelectrochemically (PEC) etched aperture. The PEC lateral undercut etch is used to selectively remove the multi-quantum well (MQW) region outside the aperture area, defined by an opaque metal mask. This PEC aperture (PECA) creates an air-gap in the passive area of the device, allowing one to achieve efficient electrical confinement within the aperture, while simultaneously achieving a large index contrast between core of the device (the MQW within the aperture) and the lateral cladding of the device (the air-gap formed by the PEC etch), leading to strong lateral confinement. Scanning electron microscopy and focused ion-beam analysis is used to investigate the precision of the PEC etch technique in defining the aperture. The fabricated single mode PECA VCSEL shows a threshold current density of ∼22 kA/cm{sup 2} (25 mA), with a peak output power of ∼180 μW, at an emission wavelength of 417 nm. The near-field emission profile shows a clearly defined single linearly polarized (LP) mode profile (LP{sub 12,1}), which is in contrast to the filamentary lasing that is often observed in III-nitride VCSELs. 2D mode profile simulations, carried out using COMSOL, give insight into the different mode profiles that one would expect to be displayed in such a device. The experimentally observed single mode operation is proposed to be predominantly a result of poor current spreading in the device. This non-uniform current spreading results in a higher injected current at the periphery of the aperture, which favors LP modes with high intensities near the edge of the aperture.

  19. Comparison of nonpolar III-nitride vertical-cavity surface-emitting lasers with tunnel junction and ITO intracavity contacts

    KAUST Repository

    Leonard, J. T.; Young, E. C.; Yonkee, B. P.; Cohen, D. A.; Shen, Chao; Margalith, T.; Ng, Tien Khee; Denbaars, S. P.; Ooi, Boon S.; Speck, J. S.; Nakamura, S.

    2016-01-01

    We report on the lasing of III-nitride nonpolar, violet, vertical-cavity surface-emitting lasers (VCSELs) with III-nitride tunnel-junction (TJ) intracavity contacts and ion implanted apertures (IIAs). The TJ VCSELs are compared to similar VCSELs with tin-doped indium oxide (ITO) intracavity contacts. Prior to analyzing device results, we consider the relative advantages of III-nitride TJs for blue and green emitting VCSELs. The TJs are shown to be most advantageous for violet and UV VCSELs, operating near or above the absorption edge for ITO, as they significantly reduce the total internal loss in the cavity. However, for longer wavelength III-nitride VCSELs, TJs primarily offer the advantage of improved cavity design flexibility, allowing one to make the p-side thicker using a thick n-type III-nitride TJ intracavity contact. This offers improved lateral current spreading and lower loss, compare to using ITO and p-GaN, respectively. These aspects are particularly important for achieving high-power CW VCSELs, making TJs the ideal intracavity contact for any III-nitride VCSEL. A brief overview of III-nitride TJ growth methods is also given, highlighting the molecular-beam epitaxy (MBE) technique used here. Following this overview, we compare 12 mu m aperture diameter, violet emitting, TJ and ITO VCSEL experimental results, which demonstrate the significant improvement in differential efficiency and peak power resulting from the reduced loss in the TJ design. Specifically, the TJ VCSEL shows a peak power of similar to 550 mu W with a threshold current density of similar to 3.5 kA/cm(2), while the ITO VCSELs show peak powers of similar to 80 mu W and threshold current densities of similar to 7 kA/cm

  20. Mesons in the nuclear Medium

    CERN Document Server

    Kotulla, M

    2006-01-01

    We discuss recent experimental results on the modification of hadron properties in a nuclear medium. Particular emphasis is placed on an $\\omega$ production experiment performed by the CBELSA/TAPS collaboration at the ELSA accelerator. The data shows a smaller $\\omega$ meson mass together with a significant increase of its width in the nuclear medium.

  1. Pions in the nuclear medium

    International Nuclear Information System (INIS)

    Chanfray, G.

    1996-07-01

    We discuss various aspects of pion physics in the nuclear medium. We first study s-wave pion-nucleus interaction in connection with chiral symmetry restoration and quark condensate in the nuclear medium. We then address the question of p-wave pion-nucleus interaction and collective pionic modes in nuclei and draw the consequences for in medium ππ correlations especially in the scalar-isoscalar channel. We finally discuss the modification of the rho meson mass spectrum at finite density and/or temperature in connection with relativistic heavy ion collisions

  2. Polar and non-polar organic aerosols from large-scale agricultural-waste burning emissions in Northern India: Implications to organic mass-to-organic carbon ratio.

    Science.gov (United States)

    Rajput, Prashant; Sarin, M M

    2014-05-01

    This study focuses on characteristics of organic aerosols (polar and non-polar) and total organic mass-to-organic carbon ratio (OM/OC) from post-harvest agricultural-waste (paddy- and wheat-residue) burning emissions in Northern India. Aerosol samples from an upwind location (Patiala: 30.2°N, 76.3°E) in the Indo-Gangetic Plain were analyzed for non-polar and polar fractions of organic carbon (OC1 and OC2) and their respective mass (OM1 and OM2). On average, polar organic aerosols (OM2) contribute nearly 85% of the total organic mass (OM) from the paddy- and wheat-residue burning emissions. The water-soluble-OC (WSOC) to OC2 ratio, within the analytical uncertainty, is close to 1 from both paddy- and wheat-residue burning emissions. However, temporal variability and relatively low WSOC/OC2 ratio (Av: 0.67±0.06) is attributed to high moisture content and poor combustion efficiency during paddy-residue burning, indicating significant contribution (∼30%) of aromatic carbon to OC2. The OM/OC ratio for non-polar (OM1/OC1∼1.2) and polar organic aerosols (OM2/OC2∼2.2), hitherto unknown for open agricultural-waste burning emissions, is documented in this study. The total OM/OC ratio is nearly identical, 1.9±0.2 and 1.8±0.2, from paddy- and wheat-residue burning emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Behavioral and electroencephalographic evaluation of the anticonvulsive activity of Moringa oleifera leaf non-polar extracts and one metabolite in PTZ-induced seizures.

    Science.gov (United States)

    González-Trujano, María Eva; Martínez-González, Claudia Lizbeth; Flores-Carrillo, Maricela; Luna-Nophal, Sara Ibeth; Contreras-Murillo, Gerardo; Magdaleno-Madrigal, Víctor Manuel

    2018-01-15

    Moringa oleifera Lamarck is a species that has long been used in high demand in folk medicine, including for the treatment of epilepsy. Nevertheless, scientific studies demonstrating its anticonvulsant properties and the nature of the bioactive constituents are lacking. The aim of this study was to evaluate the anticonvulsant activities of the Moringa oleifera leaves in non-polar vs. polar extracts using behavioral and electroencephalographic (EEG) analyses in rodents. First, PTZ (80 mg/kg, i.p.)-induced tonic-clonic seizures were assayed via a dose-response (100, 200 and 300 mg/kg, i.p.) evaluation in mice. Then, a dosage of the extracts (100 or 300 mg/kg) and one metabolite (30 mg/kg, i.p.) was selected to evaluate its effect on PTZ (35 mg/kg, i.p.)-induced EEG paroxystic activities in rats compared to the effects of ethosuximide (reference anticonvulsant drug, 100 mg/kg, i.p.). Latent onset of the first paroxystic spike, first seizure and frequency as well as seizure severity, were determined using Racine's scale. Moringa oleifera ethanol and hexane extracts produced a delay in the seizure latency in mice and rats; this effect was improved in the presence of the hexane extract containing the active metabolite hexadecanoic acid. The anticonvulsant effects were corroborated in the spectral analysis by the potency of the EEG due to a reduction in the spike frequency and amplitude, as well as in the duration and severity of the seizures. The effects of the hexane extract resembled those observed in the reference antiepileptic drug ethosuximide. Moringa oleifera leaves possess anticonvulsant activities due to the complementary of the non-polar and polar constituents. However, the non-polar constituents appear to exert an important influence via the partial participation of fatty acids, providing evidence of the effects of this plant in epilepsy therapy. Copyright © 2017. Published by Elsevier GmbH.

  4. Thermal properties of some small peptides (N-acetyl-amino acid-N′-methylamides) with non-polar side groups

    International Nuclear Information System (INIS)

    Badea, Elena; Della Gatta, Giuseppe; Pałecz, Bartłomiej

    2014-01-01

    Highlights: • T fus and Δ fus H m of methylamides of N-acetyl substituted non-polar amino acids were measured. • T fus and Δ fus H m increased as a function of the molar mass of the alkyl side chains. • DL racemates showed T fus of about 40 °C lower than those of the corresponding pure L enantiomers. • Ideal solubility of solids at T = 298.15 K was estimated based on their T fus and Δ fus S m . - Abstract: Temperatures and molar enthalpies of fusion of a series of uncharged small peptides, namely the methylamides of N-acetyl substituted glycine, α-amino-butyric acid, alanine, valine, norvaline, leucine, isoleucine, norleucine, and proline, were measured by differential scanning calorimetry (d.s.c.), and molar entropies of fusion were derived. Both L- and DL-compunds were taken into account for the chiral molecules. No solid-to-solid transitions were detected from room temperature to fusion except for N-acetyl-N′-methyl alaninamide. Comparisons were made with the values for the N-acetyl amides of the corresponding amino acids previously reported. Both L enantiomers and DL racemates of α-aminobutyric acid, alanine, valine and isoleucine methylamides displayed temperatures of fusion sharply increasing as a function of molar mass, whereas much lower values, in countertendency with their molar mass increase, were found for proline and leucine methylamides. The racemic DL crystals showed temperatures of fusion of about 40 °C lower than those of the corresponding pure L enantiomers, except for proline and leucine derivatives. The enthalpies and entropies of fusion also varied as a function of molar mass following a similar trend with that of temperatures of fusion, except for alanine derivatives which showed lower values than expected. The values of ideal solubility of solids at T = 298.15 K were estimated based on their temperatures and molar entropies of fusion. Results were discussed with reference to the packing patterns based on hydrogen bonding and

  5. Soft ionization of saturated hydrocarbons, alcohols and nonpolar compounds by negative-ion direct analysis in real-time mass spectrometry.

    Science.gov (United States)

    Cody, Robert B; Dane, A John

    2013-03-01

    Large polarizable n-alkanes (approximately C18 and larger), alcohols, and other nonpolar compounds can be detected as negative ions when sample solutions are injected directly into the sampling orifice of the atmospheric pressure interface of the time-of-flight mass spectrometer with the direct analysis in real time (DART) ion source operating in negative-ion mode. The mass spectra are dominated by peaks corresponding to [M + O2]‾(•). No fragmentation is observed, making this a very soft ionization technique for samples that are otherwise difficult to analyze by DART. Detection limits for cholesterol were determined to be in the low nanogram range.

  6. Comparison of Chlamydia trachomatis serovar L2 growth in polarized genital epithelial cells grown in three-dimensional culture with non-polarized cells

    OpenAIRE

    Dessus-Babus, Sophie; Moore, Cheryl G.; Whittimore, Judy D.; Wyrick, Priscilla B.

    2008-01-01

    A common model for studying Chlamydia trachomatis and growing chlamydial stocks uses Lymphogranuloma venereum serovar L2 and non-polarized HeLa cells. However, recent publications indicate that the growth rate and progeny yields can vary considerably for a particular strain depending on the cell line/type used, and seem to be partially related to cell tropism. In the present study, the growth of invasive serovar L2 was compared in endometrial HEC-1B and endocervical HeLa cells polarized on co...

  7. Medium modifications of vector mesons

    International Nuclear Information System (INIS)

    Pant, L.M.

    2004-01-01

    The omega photoproduction in nuclear medium with the ELSA facility at Bonn and the present status of the HADES collaboration to investigate the in-medium hadron properties in proton, heavy ions and hadron induced reactions at GSI, Darmstadt are presented. Efforts are under way to utilise the electron beam at Indore for experimental hadron physics in order to step into the intermediate energy nuclear physics regime. The skeletal outline of the high energy electron beam now available at CAT, Indore is discussed

  8. Medium effects in direct reactions

    International Nuclear Information System (INIS)

    Karakoc, M; Bertulani, C

    2013-01-01

    We discuss medium corrections of the nucleon-nucleon (NN) cross sections and their influence on direct reactions at intermediate energies ≳50 MeV/nucleon. The results obtained with free NN cross sections are compared with those obtained with a geometrical treatment of Pauli-blocking and Dirac-Bruecker methods. We show that medium corrections may lead to sizable modifications for collisions at intermediate energies and that they are more pronounced in reactions involving weakly bound nuclei.

  9. Controlled interactions between anhydrous keggin-type heteropolyacids and silica support: Preparation and characterization of well-defined silica-supported polyoxometalate species

    KAUST Repository

    Grinenval, Eva

    2010-11-11

    Anhydrous Keggin-type phosphorus heteropolyacids were deposited on partially dehydroxylated silica by using the surface organometallic chemistry (SOMC) strategy. The resulting solids were characterized by a combination of physicochemical methods including IR, Raman, 1D and 2D 1H, and 31P MAS NMR, electron microscopy experiments and density functional theory (DFT) calculations. It is shown that the main surface species is [ - Si(OH...H+)]2[H+]1[PM 12O403-] where the polyoxometalate is linked to the support by proton interaction with two silanols. Two other minor species (10% each) are formed by coordination of the polyoxometalate to the surface via the interaction between all three protons with three silanol groups or via three covalent bonds formed by dehydroxylation of the above species. Comparison of the reactivity of these solids and of compounds prepared by a classical way shows that the samples prepared by the SOMC approach contain ca. 7 times more acid sites. © 2010 American Chemical Society.

  10. Roll Compaction/Dry Granulation of Dibasic Calcium Phosphate Anhydrous-Does the Morphology of the Raw Material Influence the Tabletability of Dry Granules?

    Science.gov (United States)

    Grote, Simon; Kleinebudde, Peter

    2018-04-01

    The influence of raw material particle morphology on the tabletabilty of dry granules was investigated. Therefore, dibasic calcium phosphate anhydrous was used as a model material. One milled grade, 2 agglomerated grades with different porosities, and a functionalized structure, that is, an agglomerate formed by very small primary particles, were included. Particle size, density, and specific surface area of raw materials were measured. The starting materials and 2 fractions of dry granules were compressed to tablets. The tabletability of granules was compared to that of the powders and the influence of specific compaction force, granule size, and lubrication on tablet tensile strength was evaluated. All materials showed a loss in tabletability induced by a previous compaction step but to a varying extent. Only in case of the functionalized calcium phosphate morphology, this effect depended on the specific compaction force. In contrast to the other materials, the tabletability of functionalized calcium phosphate was influenced by the granule size. This effect was not related to an overlubrication as internal and external lubrication resulted in similar tensile strengths. A clear influence of the particle morphology on tablet strength was demonstrated by the study. The functionalized structure showed aspects of a more plastic deformation behavior. The functionalized dibasic calcium phosphate and the more porous agglomerate performed as potential filler/binder in the field of roll compaction/dry granulation. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  11. Predictive evaluation of pharmaceutical properties of direct compression tablets containing theophylline anhydrate during storage at high humidity by near-infrared spectroscopy.

    Science.gov (United States)

    Otsuka, Yuta; Yamamoto, Masahiro; Tanaka, Hideji; Otsuka, Makoto

    2015-01-01

    Theophylline anhydrate (TA) in tablet formulation is transformed into monohydrate (TH) at high humidity and the phase transformation affected dissolution behavior. Near-infrared spectroscopic (NIR) method is applied to predict the change of pharmaceutical properties of TA tablets during storage at high humidity. The tablet formulation containing TA, lactose, crystalline cellulose and magnesium stearate was compressed at 4.8 kN. Pharmaceutical properties of TA tables were measured by NIR, X-ray diffraction analysis, dissolution test and tablet hardness. TA tablet was almost 100% transformed into TH after 24 hours at RH 96%. The pharmaceutical properties of TA tablets, such as tablet hardness, 20 min dissolution amount (D20) and increase of tablet weight (TW), changed with the degree of hydration. Calibration models for TW, tablet hardness and D20 to predict the pharmaceutical properties at high-humidity conditions were developed on the basis of the NIR spectra by partial least squares regression analysis. The relationships between predicted and actual measured values for TW, tablet hardness and D20 had straight lines, respectively. From the results of NIR-chemometrics, it was confirmed that these predicted models had high accuracy to monitor the tablet properties during storage at high humidity.

  12. Anhydrous thallium hydrogen L-glutamate: polymer networks formed by sandwich layers of oxygen-coordinated thallium ions cores shielded by hydrogen L-glutamate counterions.

    Science.gov (United States)

    Bodner, Thomas; Wirnsberger, Bianca; Albering, Jörg; Wiesbrock, Frank

    2011-11-07

    Anhydrous thallium hydrogen L-glutamate [Tl(L-GluH)] crystallizes from water (space group P2(1)) with a layer structure in which the thallium ions are penta- and hexacoordinated exclusively by the oxygen atoms of the γ-carboxylate group of the hydrogen L-glutamate anions to form a two-dimensional coordination polymer. The thallium-oxygen layer is composed of Tl(2)O(2) and TlCO(2) quadrangles and is only 3 Å high. Only one hemisphere of the thallium ions participates in coordination, indicative of the presence of the 6s(2) lone pair of electrons. The thallium-oxygen assemblies are shielded by the hydrogen l-glutamate anions. Only the carbon atom of the α-carboxylate group deviates from the plane spanned by the thallium ions, the γ-carboxylate groups and the proton bearing carbon atoms, which are in trans conformation. Given the abundance of L-glutamic and L-aspartic acid in biological systems on the one hand and the high toxicity of thallium on the other hand, it is worth mentioning that the dominant structural motifs in the crystal structure of [Tl(L-GluH)] strongly resemble their corresponding analogues in the crystalline phase of [K(L-AspH)(H(2)O)(2)].

  13. Proposed replacement and operation of the anhydrous hydrogen fluoride supply and fluidized-bed chemical processing systems at Building 9212, Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1995-09-01

    The US Department of Energy (DOE) proposes to replace the existing anhydrous hydrogen fluoride (AHF) supply and fluidized-bed reactor systems for the Weapons Grade Highly Enriched Uranium Chemical Recovery and Recycle Facility, Building 9212, which is located within the Y-12 Plant on DOE's Oak Ridge Reservation in Oak Ridge, Tennessee. The proposed replacement system would be based upon modern design criteria and safety analyses. The replacement AHF supply and distribution system equipment would be located on the existing Dock 8/8A at Building 9212. Utilities would be extended to the dock to service the process equipment. The following process equipment modules would be prefabricated for installation at the modified dock: an AHF cylinder enclosure, an AHF supply manifold and vaporizer module, an AHF sump tank and transfer skid, and an AHF supply off-gas scrubber assembly module. The fluidized-bed reactor system would be constructed in an area adjacent to the existing system in Building 9212. The replacement equipment would consist of a new reduction fluidized-bed reactor, a hydrofluorination fluidized-bed reactor, and associated air emission control equipment. The no-action alternative, which is the continued operation of the existing AHF supply and fluidized-bed reactor systems, was also evaluated

  14. Utilization of diesel fuel, anhydrous ethanol and additives blend of a stationary diesel engine with rotatory pump; Utilizacao de mistura ternaria alcool, diesel e aditivo em motores do ciclo diesel com bomba de injecao rotativa

    Energy Technology Data Exchange (ETDEWEB)

    Reyes Cruz, Yordanka; Cavado Osorio, Alberto [Centro de Pesquisas de Petroleo (CEINPET), Havana (Cuba); Belchior, Carlos Rodrigues Pereira; Pereira, Pedro P.; Pinto, Nauberto Rodrigues [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Tecnologia. Dept. de Engenharia Naval e Mecanica; Aranda, Donato A. Gomes [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica

    2008-07-01

    In this paper is analyzed the performance and fuel consumption of a stationary Diesel engine, with rotary diesel fuel injection pump, using (diesel fuel + anhydrous ethanol + 0.5% additive) blend. The engine performance parameters and fuel consumption tests were performed at the Termic Machine Laboratory, located in Federal University of Rio de Janeiro, and evaluated using a MWM Series 10 model 4.10 TCA. Two test cycles were used for this test program: the tests were carried out starting from the base diesel S-500, used as a reference; the engine operated with (diesel fuel S-500 - 8% anhydrous ethanol - DIOLEFECT additive (0,5% SPAN80 + 0,1% Biomix-D)) blend. The results indicate that: the reduction levels in power and torque of engine are approximately the same which is (2,55{+-}2%), the brake specific fuel consumption increased in 1,8%. (author)

  15. Atmospheric pressure chemical ionization studies of non-polar isomeric hydrocarbons using ion mobility spectrometry and mass spectrometry with different ionization techniques

    Science.gov (United States)

    Borsdorf, H.; Nazarov, E. G.; Eiceman, G. A.

    2002-01-01

    The ionization pathways were determined for sets of isomeric non-polar hydrocarbons (structural isomers, cis/trans isomers) using ion mobility spectrometry and mass spectrometry with different techniques of atmospheric pressure chemical ionization to assess the influence of structural features on ion formation. Depending on the structural features, different ions were observed using mass spectrometry. Unsaturated hydrocarbons formed mostly [M - 1]+ and [(M - 1)2H]+ ions while mainly [M - 3]+ and [(M - 3)H2O]+ ions were found for saturated cis/trans isomers using photoionization and 63Ni ionization. These ionization methods and corona discharge ionization were used for ion mobility measurements of these compounds. Different ions were detected for compounds with different structural features. 63Ni ionization and photoionization provide comparable ions for every set of isomers. The product ions formed can be clearly attributed to the structures identified. However, differences in relative abundance of product ions were found. Although corona discharge ionization permits the most sensitive detection of non-polar hydrocarbons, the spectra detected are complex and differ from those obtained with 63Ni ionization and photoionization. c. 2002 American Society for Mass Spectrometry.

  16. Protein Thermostability Is Owing to Their Preferences to Non-Polar Smaller Volume Amino Acids, Variations in Residual Physico-Chemical Properties and More Salt-Bridges.

    Science.gov (United States)

    Panja, Anindya Sundar; Bandopadhyay, Bidyut; Maiti, Smarajit

    2015-01-01

    Protein thermostability is an important field for its evolutionary perspective of mesophilic versus thermophilic relationship and for its industrial/ therapeutic applications. Presently, a total 400 (200 thermophilic and 200 mesophilic homologue) proteins were studied utilizing several software/databases to evaluate their amino acid preferences. Randomly selected 50 homologous proteins with available PDB-structure of each group were explored for the understanding of the protein charges, isoelectric-points, hydrophilicity, hydrophobicity, tyrosine phosphorylation and salt-bridge occurrences. These 100 proteins were further probed to generate Ramachandran plot/data for the gross secondary structure prediction in and comparison between the thermophilic and mesophilic proteins. Present results strongly suggest that nonpolar smaller volume amino acids Ala (χ2 = 238.54, psalt bridges in this study. The average percentage of salt-bridge of thermophiles is found to be higher by 20% than their mesophilic homologue. The GLU-HIS and GLU-LYS salt-bridge dyads are calculated to be significantly higher (psalt-bridges and smaller volume nonpolar residues (Gly, Ala and Val) and lesser occurrence of bulky polar residues in the thermophilic proteins. A more stoichiometric relationship amongst these factors minimized the hindrance due to side chain burial and increased compactness and secondary structural stability in thermophilic proteins.

  17. Comparison of Chlamydia trachomatis serovar L2 growth in polarized genital epithelial cells grown in three-dimensional culture with non-polarized cells.

    Science.gov (United States)

    Dessus-Babus, Sophie; Moore, Cheryl G; Whittimore, Judy D; Wyrick, Priscilla B

    2008-04-01

    A common model for studying Chlamydia trachomatis and growing chlamydial stocks uses Lymphogranuloma venereum serovar L2 and non-polarized HeLa cells. However, recent publications indicate that the growth rate and progeny yields can vary considerably for a particular strain depending on the cell line/type used, and seem to be partially related to cell tropism. In the present study, the growth of invasive serovar L2 was compared in endometrial HEC-1B and endocervical HeLa cells polarized on collagen-coated microcarrier beads, as well as in HeLa cells grown in tissue culture flasks. Microscopy analysis revealed no difference in chlamydial attachment/entry patterns or in inclusion development throughout the developmental cycle between cell lines. Very comparable growth curves in both cell lines were also found using real-time PCR analysis, with increases in chlamydial DNA content of 400-500-fold between 2 and 36 h post-inoculation. Similar progeny yields with comparable infectivity were recovered from HEC-1B and HeLa cell bead cultures, and no difference in chlamydial growth was found in polarized vs. non-polarized HeLa cells. In conclusion, unlike other C. trachomatis strains such as urogenital serovar E, invasive serovar L2 grows equally well in physiologically different endometrial and endocervical environments, regardless of the host cell polarization state.

  18. Large third-order nonlinearity of nonpolar A-plane GaN film at 800 nm determined by Z-scan technology

    Science.gov (United States)

    Zhang, Feng; Han, Xiangyun

    2014-09-01

    We report an investigation on the optical third-order nonlinear property of the nonpolar A-plane GaN film. The film sample with a thickness of ~2 μm was grown on an r-plane sapphire substrate by metal-organic chemical vapor deposition system. By performing the Z-scan method combined with a mode-locked femtosecond Ti:sapphire laser (800 nm, 50 fs), the optical nonlinearity of the nonpolar A-plane GaN film was measured with the electric vector E of the laser beam being polarized parallel (//) and perpendicular (⊥) to the c axis of the film. The results show that both the third-order nonlinear absorption coefficient β and the nonlinear refractive index n2 of the sample film possess negative and large values, i.e. β// = -135 ± 29 cm/GW, n2// = -(4.0 ± 0.3) × 10-3 cm2/GW and β⊥ = -234 ± 29 cm/GW, n2⊥ = -(4.9 ± 0.4) × 10-3 cm2/GW, which are much larger than those of conventional C-plane GaN film, GaN bulk, and even the other oxide semiconductors.

  19. Exciplex fluorescence emission from simple organic intramolecular constructs in non-polar and highly polar media as model systems for DNA-assembled exciplex detectors.

    Science.gov (United States)

    Bichenkova, Elena V; Sardarian, Ali R; Wilton, Amanda N; Bonnet, Pascal; Bryce, Richard A; Douglas, Kenneth T

    2006-01-21

    Organic intramolecular exciplexes, N-(4-dimethylaminobenzyl)-N-(1-pyrenemethyl)amine (1) and N'-4-dimethylaminonaphthyl-N-(1-pyrenemethyl)amine (2), were used as model systems to reveal major factors affecting their exciplex fluorescence, and thus lay the basis for developing emissive target-assembled exciplexes for DNA-mounted systems in solution. These models with an aromatic pyrenyl hydrocarbon moiety as an electron acceptor appropriately connected to an aromatic dimethylamino electron donor component (N,N-dimethylaminophenyl or N,N-dimethylaminonaphthyl) showed strong intramolecular exciplex emission in both non-polar and highly polar solvents. The effect of dielectric constant on the maximum wavelength for exciplex emission was studied, and emission was observed for 1 and 2 over the full range of solvent from non-polar hydrocarbons up to N-methylformamide with a dielectric constant of 182. Quantum yields were determined for these intramolecular exciplexes in a range of solvents relative to that for Hoechst 33,258. Conformational analysis of 1 was performed both computationally and via qualitative 2D NMR using (1)H-NOESY experiments. The results obtained indicated the contribution of pre-folded conformation(s) to the ground state of 1 conducive to exciplex emission. This research provides the initial background for design of self-assembled, DNA-mounted exciplexes and underpins further development of exciplex-based hybridisation bioassays.

  20. Ultrafast, superhigh gain visible-blind UV detector and optical logic gates based on nonpolar a-axial GaN nanowire

    Science.gov (United States)

    Wang, Xingfu; Zhang, Yong; Chen, Xinman; He, Miao; Liu, Chao; Yin, Yian; Zou, Xianshao; Li, Shuti

    2014-09-01

    Nonpolar a-axial GaN nanowire (NW) was first used to construct the MSM (metal-semiconductor-metal) symmetrical Schottky contact device for application as visible-blind ultraviolet (UV) detector. Without any surface or composition modifications, the fabricated device demonstrated a superior performance through a combination of its high sensitivity (up to 104 A W-1) and EQE value (up to 105), as well as ultrafast (memory storage.Nonpolar a-axial GaN nanowire (NW) was first used to construct the MSM (metal-semiconductor-metal) symmetrical Schottky contact device for application as visible-blind ultraviolet (UV) detector. Without any surface or composition modifications, the fabricated device demonstrated a superior performance through a combination of its high sensitivity (up to 104 A W-1) and EQE value (up to 105), as well as ultrafast (memory storage. Electronic supplementary information (ESI) available: Details of the EDS and SAED data, supplementary results of the UV detector, and the discussion of the transport properties of the MSM Schottky contact devices. See DOI: 10.1039/c4nr03581j

  1. Interfacial B-site atomic configuration in polar (111) and non-polar (001) SrIrO3/SrTiO3 heterostructures

    Science.gov (United States)

    Anderson, T. J.; Zhou, H.; Xie, L.; Podkaminer, J. P.; Patzner, J. J.; Ryu, S.; Pan, X. Q.; Eom, C. B.

    2017-09-01

    The precise control of interfacial atomic arrangement in ABO3 perovskite heterostructures is paramount, particularly in cases where the subsequent electronic properties of the material exhibit geometrical preferences along polar crystallographic directions that feature inevitably complex surface reconstructions. Here, we present the B-site interfacial structure in polar (111) and non-polar (001) SrIrO3/SrTiO3 interfaces. The heterostructures were examined using scanning transmission electron microscopy and synchrotron-based coherent Bragg rod analysis. Our results reveal the preference of B-site intermixing across the (111) interface due to the polarity-compensated SrTiO3 substrate surface prior to growth. By comparison, the intermixing at the non-polar (001) interface is negligible. This finding suggests that the intermixing may be necessary to mitigate epitaxy along heavily reconstructed and non-stoichiometric (111) perovskite surfaces. Furthermore, this preferential B-site configuration could allow the geometric design of the interfacial perovskite structure and chemistry to selectively engineer the correlated electronic states of the B-site d-orbital.

  2. Interfacial B-site atomic configuration in polar (111 and non-polar (001 SrIrO3/SrTiO3 heterostructures

    Directory of Open Access Journals (Sweden)

    T. J. Anderson

    2017-09-01

    Full Text Available The precise control of interfacial atomic arrangement in ABO3 perovskite heterostructures is paramount, particularly in cases where the subsequent electronic properties of the material exhibit geometrical preferences along polar crystallographic directions that feature inevitably complex surface reconstructions. Here, we present the B-site interfacial structure in polar (111 and non-polar (001 SrIrO3/SrTiO3 interfaces. The heterostructures were examined using scanning transmission electron microscopy and synchrotron-based coherent Bragg rod analysis. Our results reveal the preference of B-site intermixing across the (111 interface due to the polarity-compensated SrTiO3 substrate surface prior to growth. By comparison, the intermixing at the non-polar (001 interface is negligible. This finding suggests that the intermixing may be necessary to mitigate epitaxy along heavily reconstructed and non-stoichiometric (111 perovskite surfaces. Furthermore, this preferential B-site configuration could allow the geometric design of the interfacial perovskite structure and chemistry to selectively engineer the correlated electronic states of the B-site d-orbital.

  3. High conductive, long-term durable, anhydrous proton conductive solid-state electrolyte based on a metal-organic framework impregnated with binary ionic liquids: Synthesis, characteristic and effect of anion

    Science.gov (United States)

    Chen, Hui; Han, Shu-Yan; Liu, Rui-Heng; Chen, Teng-Fei; Bi, Kai-Lun; Liang, Jian-Bo; Deng, Yu-Heng; Wan, Chong-Qing

    2018-02-01

    Incorporating ionic liquids (abbreviated as ILs) into porous metal-organic framework (MOF) to obtain ILs@MOF nanocomposites is documented as a feasible method to achieve new type of anhydrous proton conductor with high performance. We newly synthesized a series of ILs with different acid counter anions (R-SO3-) and their ILs@MOF hybrid materials, i.e. SA-EIMS@MIL-101, MSA-EIMS@MIL-101 and PTSA-EIMS@MIL-101 (SA = sulfate acid, MSA = methanesulfonate acid, PTSA = p-toluenesulfonate acid, EIMS = 1-(1-ethyl-3-imidazolium)propane-3-sulfonate). Such hybrid materials displayed as anhydrous proton conduction with long-term durability even heated at 150 °C open to air. σ value of SA-EIMS@MIL-101 is up to 1.89 × 10-3 S cm-1, being in the range of the most conductive MOF-based materials. MOF support exhibited favorable proton transport and long-term retention for ILs. Anion volumes of R-SO3- displayed significant effects on the proton conductivity of such hybrid ILs@MOF materials. The smaller the van der Waals volume of R-SO3- is, the higher the conductivity of ILs@MOF is. This work suggests that the combination of a variety of the incorporated ILs and a MOF framework would afford high proton transport and gives an idea to explore the safe, anhydrous, solid-state electrolyte for high temperature proton exchange membrane fuel cell.

  4. Properties of the nuclear medium

    International Nuclear Information System (INIS)

    Baldo, M; Burgio, G F

    2012-01-01

    We review our knowledge on the properties of the nuclear medium that have been studied, over many years, on the basis of many-body theory, laboratory experiments and astrophysical observations. Throughout the presentation particular emphasis is placed on the possible relationship and links between the nuclear medium and the structure of nuclei, including the limitations of such an approach. First we consider the realm of phenomenological laboratory data and astrophysical observations and the hints they can give on the characteristics that the nuclear medium should possess. The analysis is based on phenomenological models, that however have a strong basis on physical intuition and an impressive success. More microscopic models are also considered, and it is shown that they are able to give invaluable information on the nuclear medium, in particular on its equation of state. The interplay between laboratory experiments and astrophysical observations is particularly stressed, and it is shown how their complementarity enormously enriches our insights into the structure of the nuclear medium. We then introduce the nucleon–nucleon interaction and the microscopic many-body theory of nuclear matter, with a critical discussion about the different approaches and their results. The Landau–Fermi liquid theory is introduced and briefly discussed, and it is shown how fruitful it can be in discussing the macroscopic and low-energy properties of the nuclear medium. As an illustrative example, we discuss neutron matter at very low density, and it is shown how it can be treated within the many-body theory. The general bulk properties of the nuclear medium are reviewed to indicate at which stage of our knowledge we stand, taking into account the most recent developments both in theory and experiments. A section is dedicated to the pairing problem. The connection with nuclear structure is then discussed, on the basis of the energy density functional method. The possibility of

  5. 1 Medium Regiment, (SAHA), SAA

    African Journals Online (AJOL)

    Scientia Militaria: South African Journal of Military Studies. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 16, No 4 (1986) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. 1 Medium Regiment, (S.A.H.A.), ...

  6. Hadron photoproduction at medium energy

    International Nuclear Information System (INIS)

    Dainton, J.B.

    1985-04-01

    Results from measurements of multibody photoproduction at medium incident photon energy (2.8 to 4.8 GeV) are presented and discussed. Particular emphasis is placed on topics which are not well understood and which therefore motivate experiments with the upgraded electron accelerator and storage ring ELSA at the University of Bonn, FR Germany. (author)

  7. Animal Locomotion in Different Mediums

    Indian Academy of Sciences (India)

    Wetlands are repositories of unique biodiversity. Wetlandorganisms are well adapted to their habitat, lying at theinterface of aquatic and terrestrial environments. In order tounderstand their adaptations in a better way, it is essential tograsp the basic properties of the medium in which variousorganisms live. This is attempted ...

  8. Late Neoproterozoic to Carboniferous genesis of A-type magmas in Avalonia of northern Nova Scotia: repeated partial melting of anhydrous lower crust in contrasting tectonic environments

    Science.gov (United States)

    Murphy, J. Brendan; Shellnutt, J. Gregory; Collins, William J.

    2018-03-01

    Avalonian rocks in northern mainland Nova Scotia are characterized by voluminous 640-600 Ma calc-alkalic to tholeiitic mafic to felsic magmas produced in a volcanic arc. However, after the cessation of arc activity, repeated episodes of felsic magmatism between ca. 580 Ma and 350 Ma are dominated by A-type geochemical characteristics. Sm-Nd isotopic data, combined with zircon saturation temperature estimates, indicate that these magmas were formed by high temperature (800-1050 °C) melting of the same anhydrous crustal source. Regional tectonic considerations indicate that A-type felsic magmatism was produced (1) at 580 Ma in a San Andreas-type strike slip setting, (2) at 495 Ma as Avalonia rifted off Gondwana, (3) at 465 and 455 in an ensialic island arc environment and (4) at 360-350 Ma during post-collisional, intra-continental strike-slip activity as Avalonia was translated dextrally along the Laurentian margin. These results attest to the importance of crustal source, rather than tectonic setting, in the generation of these A-type magmas and are an example of how additional insights are provided by comparing the geochemical and isotopic characteristics of igneous suites of different ages within the same terrane. They also suggest that the shallow crustal rocks in northern mainland Nova Scotia were not significantly detached from their lower crustal source between ca. 620 Ma and 350 Ma, a time interval that includes the separation of Avalonia from Gondwana, its drift and accretion to Laurentia as well as post-accretionary strike-slip displacement.

  9. Solid-Phase Microextraction Coupled to Capillary Atmospheric Pressure Photoionization-Mass Spectrometry for Direct Analysis of Polar and Nonpolar Compounds.

    Science.gov (United States)

    Mirabelli, Mario F; Zenobi, Renato

    2018-04-17

    A novel capillary ionization source based on atmospheric pressure photoionization (cAPPI) was developed and used for the direct interfacing between solid-phase microextraction (SPME) and mass spectrometry (MS). The efficiency of the source was evaluated for direct and dopant-assisted photoionization, analyzing both polar (e.g., triazines and organophosphorus pesticides) and nonpolar (polycyclic aromatic hydrocarbons, PAHs) compounds. The results show that the range of compound polarity, which can be addressed by direct SPME-MS can be substantially extended by using cAPPI, compared to other sensitive techniques like direct analysis in real time (DART) and dielectric barrier discharge ionization (DBDI). The new source delivers a very high sensitivity, down to sub parts-per-trillion (ppt), making it a viable alternative when compared to previously reported and less comprehensive direct approaches.

  10. Photoluminescence spectroscopy and positron annihilation spectroscopy probe of alloying and annealing effects in nonpolar m-plane ZnMgO thin films

    Science.gov (United States)

    Yang, A. L.; Song, H. P.; Liang, D. C.; Wei, H. Y.; Liu, X. L.; Jin, P.; Qin, X. B.; Yang, S. Y.; Zhu, Q. S.; Wang, Z. G.

    2010-04-01

    Temperature-dependent photoluminescence characteristics of non-polar m-plane ZnO and ZnMgO alloy films grown by metal organic chemical vapor deposition have been studied. The enhancement in emission intensity caused by localized excitons in m-plane ZnMgO alloy films was directly observed and it can be further improved after annealing in nitrogen. The concentration of Zn vacancies in the films was increased by alloying with Mg, which was detected by positron annihilation spectroscopy. This result is very important to directly explain why undoped Zn1-xMgxO thin films can show p-type conduction by controlling Mg content, as discussed by Li et al. [Appl. Phys. Lett. 91, 232115 (2007)].

  11. Design of a 50/50 splitting ratio non-polarizing beam splitter based on the modal method with fused-silica transmission gratings

    Science.gov (United States)

    Zhao, Huajun; Yuan, Dairong; Ming, Hai

    2011-04-01

    The optical design of a beam splitter that has a 50/50 splitting ratio regardless of the polarization is presented. The non-polarizing beam splitter (NPBS) is based on the fused-silica rectangular transmission gratings with high intensity tolerance. The modal method has been used to estimate the effective index of the modes excited in the grating region for TE and TM polarizations. If a phase difference equals an odd multiples of π/2 for the first two modes (i.e. modes 0 and 1), the incident light will be diffracted into the 0 and -1 orders with about 50% and 50% diffraction efficiency for TM and TE polarizations, respectively.

  12. Polarization-independent rapidly tunable optical add-drop multiplexer utilizing non-polarizing beam splitters in Ti:LiNbO3

    Science.gov (United States)

    Shin, Yong-Wook; Sung, Won Ju; Eknoyan, O.; Madsen, C. K.; Taylor, H. F.

    2012-04-01

    A polarization-independent four-port wavelength-tunable optical add drop multiplexer (OADM) that utilizes non-polarizing relaxed beam splitters has been analyzed and demonstrated in Ti:LiNbO3 at the 1530 nm wavelength regime. The design utilizes an asymmetric interferometer configuration with strain induced index grating for polarization coupling along its arms that are shifted in position relative to each other. Experimental results of the filter response agree with theoretical predictions. Electrooptic tuning over a range of 15.7 nm at a rate of 0.08 nm/V has been measured. A temporal response < 46 ns to a 20 V step change in tuning voltage has been demonstrated. Fiber-to-fiber insertion loss is ~ 6.5 dB.

  13. Holographic Renormalization in Dense Medium

    International Nuclear Information System (INIS)

    Park, Chanyong

    2014-01-01

    The holographic renormalization of a charged black brane with or without a dilaton field, whose dual field theory describes a dense medium at finite temperature, is investigated in this paper. In a dense medium, two different thermodynamic descriptions are possible due to an additional conserved charge. These two different thermodynamic ensembles are classified by the asymptotic boundary condition of the bulk gauge field. It is also shown that in the holographic renormalization regularity of all bulk fields can reproduce consistent thermodynamic quantities and that the Bekenstein-Hawking entropy is nothing but the renormalized thermal entropy of the dual field theory. Furthermore, we find that the Reissner-Nordström AdS black brane is dual to a theory with conformal matter as expected, whereas a charged black brane with a nontrivial dilaton profile is mapped to a theory with nonconformal matter although its leading asymptotic geometry still remains as AdS space

  14. Medium modifications with recoil polarization

    Energy Technology Data Exchange (ETDEWEB)

    Brand, J.F.J. van den [Nationaal Instituut voor Kernfysica en Hoge Energiefysica, Amsterdam (Netherlands); Ent, R. [CEBAF, Newport News, VA (United States)

    1994-04-01

    The authors show that the virtual Compton scattering process allows for a precise study of the off-shell electron-nucleon vertex. In a separable model, they show the sensitivity to new unconstrained structure functions of the nucleon, beyond the usual Dirac and Pauli form factors. In addition, they show the sensitivity to bound nucleon form factors using the reaction 4He({rvec e},e{prime},{rvec p}){sup 3}H. A nucleon embedded in a nucleus represents a complex system. Firstly, the bound nucleon is necessarily off-shell and in principle a complete understanding of the dynamical structure of the nucleon is required in order to calculate its off-shell electromagnetic interaction. Secondly, one faces the possibility of genuine medium effects, such as for example quark-exchange contributions. Furthermore, the electromagnetic coupling to the bound nucleon is dependent on the nuclear dynamics through the self-energy of the nucleon in the nuclear medium.

  15. Medium modifications with recoil polarization

    International Nuclear Information System (INIS)

    Brand, J.F.J. van den; Ent, R.

    1994-01-01

    The authors show that the virtual Compton scattering process allows for a precise study of the off-shell electron-nucleon vertex. In a separable model, they show the sensitivity to new unconstrained structure functions of the nucleon, beyond the usual Dirac and Pauli form factors. In addition, they show the sensitivity to bound nucleon form factors using the reaction 4He(rvec e,e',rvec p) 3 H. A nucleon embedded in a nucleus represents a complex system. Firstly, the bound nucleon is necessarily off-shell and in principle a complete understanding of the dynamical structure of the nucleon is required in order to calculate its off-shell electromagnetic interaction. Secondly, one faces the possibility of genuine medium effects, such as for example quark-exchange contributions. Furthermore, the electromagnetic coupling to the bound nucleon is dependent on the nuclear dynamics through the self-energy of the nucleon in the nuclear medium

  16. Determination of inorganic arsenic in algae using bromine halogenation and on-line nonpolar solid phase extraction followed by hydride generation atomic fluorescence spectrometry.

    Science.gov (United States)

    Zhang, Weihong; Qi, Yuehan; Qin, Deyuan; Liu, Jixin; Mao, Xuefei; Chen, Guoying; Wei, Chao; Qian, Yongzhong

    2017-08-01

    Accurate, stable and fast analysis of toxic inorganic arsenic (iAs) in complicated and arsenosugar-rich algae matrix is always a challenge. Herein, a novel analytical method for iAs in algae was reported, using bromine halogenation and on-line nonpolar solid phase extraction (SPE) followed by hydride generation atomic fluorescence spectrometry (HG-AFS). The separation of iAs from algae was first performed by nonpolar SPE sorbent using Br - for arsenic halogenation. Algae samples were extracted with 1% perchloric acid. Then, 1.5mL extract was reduced by 1% thiourea, and simultaneously reacted (for 30min) with 50μL of 10% KBr for converting iAs to AsBr 3 after adding 3.5mL of 70% HCl to 5mL. A polystyrene (PS) resin cartridge was employed to retain arsenicals, which were hydrolyzed, eluted from the PS resin with H 2 O, and categorized as iAs. The total iAs was quantified by HG-AFS. Under optimum conditions, the spiked recoveries of iAs in real algae samples were in the 82-96% range, and the method achieved a desirable limit of detection of 3μgkg -1 . The inter-day relative standard deviations were 4.5% and 4.1% for spiked 100 and 500μgkg -1 respectively, which proved acceptable for this method. For real algae samples analysis, the highest presence of iAs was found in sargassum fusiforme, followed by kelp, seaweed and laver. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. The impact of nonpolar lipids on the regulation of the steryl ester hydrolases Tgl1p and Yeh1p in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Klein, Isabella; Korber, Martina; Athenstaedt, Karin; Daum, Günther

    2017-12-01

    In the yeast Saccharomyces cerevisiae degradation of steryl esters is catalyzed by the steryl ester hydrolases Tgl1p, Yeh1p and Yeh2p. The two steryl ester hydrolases Tgl1p and Yeh1p localize to lipid droplets, a cell compartment storing steryl esters and triacylglycerols. In the present study we investigated regulatory aspects of these two hydrolytic enzymes, namely the gene expression level, protein amount, stability and enzyme activity of Tgl1p and Yeh1p in strains lacking both or only one of the two major nonpolar lipids, steryl esters and triacylglycerols. In a strain lacking both nonpolar lipids and consequently lipid droplets, Tgl1p as well as Yeh1p were present at low amount, became highly unstable compared to wild-type cells, and lost their enzymatic activity. Under these conditions both steryl ester hydrolases were retained in the endoplasmic reticulum. The lack of steryl esters alone was not sufficient to cause an altered intracellular localization of Tgl1p and Yeh1p. Surprisingly, the stability of Tgl1p and Yeh1p was markedly reduced in a strain lacking triacylglycerols, but their capacity to mobilize steryl esters remained unaffected. We also tested a possible cross-regulation of Tgl1p and Yeh1p by analyzing the behavior of each hydrolase in the absence of its counterpart steryl ester hydrolases. In summary, this study demonstrates a strong regulation of the two lipid droplet associated steryl ester hydrolases Tgl1p and Yeh1p due to the presence/absence of their host organelle. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Transfection efficiency and uptake process of polyplexes in human lung endothelial cells: a comparative study in non-polarized and polarized cells.

    Science.gov (United States)

    Mennesson, Eric; Erbacher, Patrick; Piller, Véronique; Kieda, Claudine; Midoux, Patrick; Pichon, Chantal

    2005-06-01

    Following systemic administration, polyplexes must cross the endothelium barrier to deliver genes to the target cells underneath. To design an efficient gene delivery system into lung epithelium, we evaluated capture and transfection efficiencies of DNA complexed with either Jet-PEI (PEI-polyplexes) or histidylated polylysine (His-polyplexes) in human lung microvascular endothelial cells (HLMEC) and tracheal epithelial cells. After optimizing growth conditions to obtain a tight HLMEC monolayer, we characterized uptake of polyplexes by flow cytometry and evaluated their transfection efficiency. Polyplexes were formulated as small particles. YOYO-labelled plasmid fluorescence intensity and luciferase activity were used as readouts for uptake and gene expression, respectively. PEI-polyplexes were more efficiently taken up than His-polyplexes by both non-polarized (2-fold) and polarized HLMEC (10-fold). They were mainly internalized by a clathrin-dependent pathway whatever the cell state. In non-polarized cells, His-polyplexes entered also mainly via a clathrin-dependent pathway but with an involvement of cholesterol. The cell polarization decreased this way and a clathrin-independent pathway became predominant. PEI-polyplexes transfected more efficiently HLMEC than His-polyplexes (10(7) vs. 10(5) relative light units (RLU)/mg of proteins) with a more pronounced difference in polarized cells. In contrast, no negative effect of the cell polarization was observed with tracheal epithelial cells in which both polyplexes had comparable efficiency. We show that the efficiency of polyplex uptake by HLMEC and their internalization mechanism are polymer-dependent. By contrast with His-polyplexes, the HLMEC polarization has little influence on the uptake process and on the transfection efficiency of PEI-polyplexes. Copyright (c) 2005 John Wiley & Sons, Ltd.

  19. Epitaxial growth of Sb-doped nonpolar a-plane ZnO thin films on r-plane sapphire substrates by RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hou-Guang, E-mail: houguang@isu.edu.tw [Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan (China); Hung, Sung-Po [Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan (China)

    2014-02-15

    Highlights: ► Sb-doped nonpolar a-plane ZnO layers were epitaxially grown on sapphire substrates. ► Crystallinity and electrical properties were studied upon growth condition and doping concentration. ► The out-of-plane lattice spacing of ZnO films reduces monotonically with increasing Sb doping level. ► The p-type conductivity of ZnO:Sb film is closely correlated with annealing condition and Sb doping level. -- Abstract: In this study, the epitaxial growth of Sb-doped nonpolar a-plane (112{sup ¯}0) ZnO thin films on r-plane (11{sup ¯}02) sapphire substrates was performed by radio-frequency magnetron sputtering. The influence of the sputter deposition conditions and Sb doping concentration on the microstructural and electrical properties of Sb-doped ZnO epitaxial films was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and the Hall-effect measurement. The measurement of the XRD phi-scan indicated that the epitaxial relationship between the ZnO:Sb layer and sapphire substrate was (112{sup ¯}0){sub ZnO}//(11{sup ¯}02){sub Al{sub 2O{sub 3}}} and [11{sup ¯}00]{sub ZnO}//[112{sup ¯}0]{sub Al{sub 2O{sub 3}}}. The out-of-plane a-axis lattice parameter of ZnO films was reduced monotonically with the increasing Sb doping level. The cross-sectional transmission electron microscopy (XTEM) observation confirmed the absence of any significant antimony oxide phase segregation across the thickness of the Sb-doped ZnO epitaxial film. However, the epitaxial quality of the films deteriorated as the level of Sb dopant increased. The electrical properties of ZnO:Sb film are closely correlated with post-annealing conditions and Sb doping concentrations.

  20. Medium Theory and Social Systems

    DEFF Research Database (Denmark)

    Tække, Jesper

      the  possibility  for  observation both of a social micro and a social macro level from a medium perspective. In the next  section  the paper  frames  the macro  level by  a  tentative  synthesis of  the medium  theory  and  the  sociological systems theory briefly describing a socio......-evolutionary process where new media alter  the societal capacity to handle complexity  in  time and space.  In  this section it becomes probable  that  by  means  of  different  media,  social  systems  give  different  possibilities  for  actual  social  performance.  In a way,  social  systems  themselves can be......  seen as medium  for  formation. Finally  the  paper  takes  the micro  level  perspective  by  applying  the  theory  to  newsgroups,  interpreting  them as self-organizing interactive systems giving a differentiated and diversified scope for social  inclusion.  ...

  1. Medium energy ion scattering (MEIS)

    International Nuclear Information System (INIS)

    Dittmann, K.; Markwitz, A.

    2009-01-01

    This report gives an overview about the technique and experimental study of medium energy ion scattering (MEIS) as a quantitative technique to determine and analyse the composition and geometrical structure of crystalline surfaces and near surface-layers by measuring the energy and yield of the backscattered ions. The use of a lower energy range of 50 to 500 keV accelerated ions impinging onto the target surface and the application of a high-resolution electrostatic energy analyser (ESA) makes medium energy ion scattering spectroscopy into a high depth resolution and surface-sensitive version of RBS with less resulting damage effects. This report details the first steps of research in that field of measurement technology using medium energetic backscattered ions detected by means of a semiconductor radiation detector instead of an ESA. The study of medium energy ion scattering (MEIS) has been performed using the 40 keV industrial ion implanter established at GNS Sciences remodelled with supplementary high voltage insulation for the ion source in order to apply voltages up to 45 kV, extra apertures installed in the beamline and sample chamber in order to set the beam diameter accurately, and a semiconductor radiation detector. For measurement purposes a beam of positive charged helium ions accelerated to an energy of about 80 keV has been used impinging onto target surfaces of lead implanted into silicon (PbSi), scandium implanted into aluminium (ScAl), aluminium foil (Al) and glassy carbon (C). First results show that it is possible to use the upgraded industrial implanter for medium energy ion scattering. The beam of 4 He 2+ with an energy up to 88 keV has been focussed to 1 mm in diameter. The 5 nA ion beam hit the samples under 2 x 10 -8 mbar. The results using the surface barrier detector show scattering events from the samples. Cooling of the detector to liquid nitrogen temperatures reduced the electronic noise in the backscattering spectrum close to zero. A

  2. Research on anhydrous hydrazine synthesis

    International Nuclear Information System (INIS)

    Gaussens, G.

    1967-03-01

    The first part of this work concerns the radiolysis of pure liquid ammonia. The fundamental importance of the dose rate and of the dose on the yield of radiolytic products has been demonstrated. By using a capture solute at concentrations of between 10 -3 and 1.2 mole s/litre, it has been possible to determine the yields of radicals and of molecules in the irradiated pure ammonia. During later work, it was possible to determine, by systematically varying the physico-chemical parameters, the most favorable conditions for carrying out the radiosynthesis; the maximum radiochemical yield of the hydrazine obtained has a value: G (N 2 H 4 ) = 2.2/100 eV. An analysis of the molecular yields in the presence of deuterated solutes makes it possible to explain partially the role of the capture species. A project is also described for an installation producing hydrazine continuously; it is followed by an economic study of the process. From this work it appears that the yields of hydrazine obtained justify an industrial application, especially if strong radiation sources are available, for example nuclear reactors. (author) [fr

  3. Enhancement of catalytic activity of enzymes by heating in anhydrous organic solvents: 3D structure of a modified serine proteinase at high resolution.

    Science.gov (United States)

    Sharma, S; Tyagi, R; Gupta, M N; Singh, T P

    2001-01-01

    For the first time, it is demonstrated that exposure of an enzyme to anhydrous organic solvents at optimized high temperature enhances its catalytic power through local changes at the binding region. Six enzymes, namely, proteinase K, wheat germ acid phosphatase, alpha-amylase, beta-glucosidase, chymotrypsin and trypsin were exposed to acetonitrile at 70 degrees C for three hr. The activities of these enzymes were found to be considerably enhanced. In order to understand the basis of this change in the activity of these enzymes, proteinase K was analyzed in detail using X-ray diffraction method. The overall structure of the enzyme was found to be similar to the native structure in aqueous environment. The hydrogen bonding system of the catalytic triad remained intact after the treatment. However, the water structure in the substrate binding site underwent some rearrangement as some of the water molecules were either displaced or completely absent. The most striking observation concerning the water structure was the complete deletion of the water molecule which occupied the position at the so-called oxyanion hole in the active site of the native enzyme. Three acetonitrile molecules were found in the present structure. All the acetonitrile molecules were located in the recognition site. Interlinked through water molecules, the sites occupied by acetonitrile molecules were independent of water molecules. The acetonitrile molecules are involved in extensive interactions with the protein atoms. The methyl group of one of the acetonitrile molecules (CCN1) interacts simultaneously with the hydrophobic side chains of Leu 96, Ile 107 and Leu 133. The development of such a hydrophobic environment at the recognition site introduced a striking conformation change in Ile 107 by rotating its side chain about C alpha-C beta bond by 180 degrees to bring about the delta-methyl group within the range of attractive van der Waals interactions with the methyl group of CCN1. A similar

  4. Accretion from an inhomogeneous medium

    International Nuclear Information System (INIS)

    Livio, M.; Soker, N.; Koo, M. de; Savonije, G.J.

    1986-01-01

    The problem of accretion by a compact object from an inhomogeneous medium is studied in the general γnot=1 case. The mass accretion rate is found to decrease with increasing γ. The rate of accretion of angular momentum is found to be significantly lower than the rate at which angular momentum is deposited into the Bondi-Hoyle, symmetrical, accretion cylinder. The consequences of the results are studied for the cases of neutron stars accreting from the winds of early-type companions and white dwarfs and main-sequence stars accreting from winds of cool giants. (author)

  5. A Heterogeneous Medium Analytical Benchmark

    International Nuclear Information System (INIS)

    Ganapol, B.D.

    1999-01-01

    A benchmark, called benchmark BLUE, has been developed for one-group neutral particle (neutron or photon) transport in a one-dimensional sub-critical heterogeneous plane parallel medium with surface illumination. General anisotropic scattering is accommodated through the Green's Function Method (GFM). Numerical Fourier transform inversion is used to generate the required Green's functions which are kernels to coupled integral equations that give the exiting angular fluxes. The interior scalar flux is then obtained through quadrature. A compound iterative procedure for quadrature order and slab surface source convergence provides highly accurate benchmark qualities (4- to 5- places of accuracy) results

  6. Charmed hadrons in nuclear medium

    International Nuclear Information System (INIS)

    Tolos, L.; Gamermann, D.; Molina, R.; Nieves, J.; Oset, E.; Garcia-Recio, C.; Ramos, A.

    2010-01-01

    We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the open-charm meson spectral functions. We discuss the implications of the in-medium properties of open-charm mesons on the D s0 (2317) and the predicted X(3700) scalar resonances. (authors)

  7. Development of brachytherapy medium doserate

    International Nuclear Information System (INIS)

    Atang Susila; Ari Satmoko; Ahmad Rifai; Kristiyanti

    2010-01-01

    Brachytherapy has proven to be an effective treatment for different types of cancers and it become a common treatment modality in most radiotherapy clinics. PRPN has had experience in development of Low Dose Rate Brachytherapy for cervix cancer treatment. However the treatment process using LDR device needs 5 hours in time that the patient feel uncomfort. Therefore PRPN develops Medium Dose Rate Brachytherapy with radiation activity not more than 5 Currie. The project is divided into two stages. Purchasing of TPS software and TDS design are held in 2010, and the construction will be in 2011. (author)

  8. Medium modification of fragmentation functions

    International Nuclear Information System (INIS)

    Nezza, Pasquale Di

    2007-01-01

    Deep Inelastic Scattering is the cleanest process to investigate the space-time evolution of the hadronization. This was studied by the influence of the nuclear medium on lepto-production of hadrons at the Hermes experiment at DESY in semi-inclusive DIS of 27.6 GeV positrons off deuterium, nitrogen, krypton and xenon targets. The differential multiplicity for heavy targets relative to that of deuterium has been measured for the first time for various identified hadrons (φ + , φ - , φ 0 , k + , k - , p and anti-p) as a function of the virtual photon energy ?, the fraction z of this energy transferred to the hadron, and the hadron transverse momentum squared p 2 t . The distribution of the hadron transverse momentum is broadened towards high p 2 t in the nuclear medium, in a manner resembling the Cronin effect observed in collisions of heavy ions and protons with nuclei. The pt -broadening results give also important information about the pre-hadron formation time. Moreover, by studying the hadron attenuation of the leading and sub-leading hadrons, we report, for the first time, the possibility to better understand the hadron absorption and the energy loss contributions to the attenuation mechanism. (Author)

  9. Gravitational lensing in plasmic medium

    Energy Technology Data Exchange (ETDEWEB)

    Bisnovatyi-Kogan, G. S., E-mail: gkogan@iki.rssi.ru; Tsupko, O. Yu., E-mail: tsupko@iki.rssi.ru [Russian Academy of Sciences, Space Research Institute (Russian Federation)

    2015-07-15

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.

  10. Unsaturated medium hydrocarbons pollution evaluation

    International Nuclear Information System (INIS)

    Di Luise, G.

    1991-01-01

    When the so called porous unsaturated medium, that's the vertical subsoil section between both the ground and water-table level, is interested by a hydrocarbons spill, the problem to evaluate the pollution becomes difficult: considering, essentially, the natural coexistence in it of two fluids, air and water, and the interactions between them. This paper reports that the problems tend to increase when a third fluid, the pollutant, immiscible with water, is introduced into the medium: a three-phases flow, which presents several analogies with the flow conditions present in an oil-reservoir, will be established. In such a situation, it would be very useful to handle the matter by the commonly used parameters in the oil reservoirs studies such as: residual saturation, relative permeability, phases mobility, to derive a first semiquantitative estimation of the pollution. The subsoil pollution form hydrocarbons agents is one of the worldwide more diffused causes of contamination: such events are generally referable to two main effects: accidental (oil pipeline breakdowns, e.g.), and continuous (underground tanks breaks, industrial plants leakages, e.g.)

  11. Is the intercloud medium pervasive

    International Nuclear Information System (INIS)

    Heiles, C.

    1980-01-01

    We consider the pervasiveness of the ''not strongly absorbing'' (NSA) H I gas, which is the intercloud medium in steady state theories of the interstellar medium. We study the question by analyzing wide emission components in nearby gas, and the absence of absorption components in distant gas. We conclude that the NSA material is deficient in the immediately local solar vicinity. In nearby regions it contains 38% of the interstellar H I; it is generally pervasive and often has internal motions which greatly increase its velocity dispersion above the 5 km s -1 minimum value. It contains large holes, perhaps ranging up to 400 pc diameter, which probably occupy 10--20% of the volume. In distant regions the NSA material seems to be pervasive outside 8 kpc galactic radius. For galactic radii between 8 and 10 kpc its thickness agrees with previous determinations of 370 pc for nearby regions. Outside 10 kpc the thickness increases dramatically. Inside 8 kpc there are no data

  12. How Does the Medium Affect the Message?

    Science.gov (United States)

    Dommermuth, William P.

    1974-01-01

    This experimental comparison of the advertising effectiveness of television, movies, radio, and print finds no support for McLuhan's idea that television is a "cool" medium and movies are a "hot" medium. (RB)

  13. PECULIARITIES OF WATER FREEZING IN CRYOPROTECTIVE MEDIUM IMPLEMENTED IN A MATRIX OF HYDROPHOBIC SILICA BULL SPERM

    Directory of Open Access Journals (Sweden)

    V. V. Turov

    2014-06-01

    Full Text Available The study of the process of melting water in lactose-glycerol-yolk kriomedium containing gametes bull, incorporated in the hydrophobic silica powder, which are adsorbed on the surface of fixed amounts of nonpolar hydrocarbon – n-decane was the aim of the work. The possibility of water polyassociates structuring with a solid surface of interfacial water and solubility of trifluoroethanoic acid in it have been studied. Thereat survival of the germ cell after contact with the surface was not analyzed. State of water in initial cryoprotective glycerol-lactose-yolk medium and hydrophobic nanosilica TS-100 containing n-decane additive adsorbed on its surface incorporated in a matrix was studied using low-temperature 1H-NMR spectroscopy method. It is shown that the solid matrix induces formation of 6–7 water molecules per each dean molecule at the interface, which do not take part in formation of hydrogen bonds, and a sharp radius decrease (from 100 to 20 nm of ice crystals formed in cell suspension at its freezing. The results could give rise to safety improving of their cells at their cryopreservation and low temperature storage conditions by incorporating into a powder composite environment.

  14. 27 CFR 19.914 - Medium plants.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Medium plants. 19.914... OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Distilled Spirits For Fuel Use Permits § 19.914 Medium plants. Any person wishing to establish a medium plant shall make application for and obtain in...

  15. Mapping of moveout in a TTI medium

    KAUST Repository

    Stovas, A.; Alkhalifah, Tariq Ali

    2012-01-01

    To compute moveout in a transversely isotropic medium with tilted symmetry axis is a very complicated problem. We propose to split this problem into two parts. First, to compute the moveout in a corresponding VTI medium. Second, to map the computed moveout to a TTI medium.

  16. Medium-size nuclear plants

    International Nuclear Information System (INIS)

    Vogelweith, L.; Lavergne, J.C.; Martinot, G.; Weiss, A.

    1977-01-01

    CEA (TECHNICATOME) has developed a range of pressurized water reactors of the type ''CAS compact'' which are adapted to civil ship propulsion, or to electric power production, combined possibly with heat production, up to outputs equivalent to 125 MWe. Nuclear plants equipped with these reactors are suitable to medium-size electric networks. Among the possible realizations, two types of plants are mentioned as examples: 1) Floating electron-nuclear plants; and 2) Combined electric power and desalting plants. The report describes the design characteristics of the different parts of a 125 MWe unit floating electro-nuclear plant: nuclear steam system CAS 3 G, power generating plant, floating platform for the whole plant. The report gives attention to the different possibilities according to site conditions (the plant can be kept floating, in a natural or artificial basin, it can be put aground, ...) and to safety and environment factors. Such unit can be used in places where there is a growing demand in electric power and fresh water. The report describes how the reactor, the power generating plant and multiflash distillation units of an electric power-desalting plant can be combined: choice of the ratio water output/electric power output, thermal cycle combination, choice of the gain ratio, according to economic considerations, and to desired goal of water output. The report analyses also some technical options, such as: choice of the extraction point of steam used as heat supply of the desalting station (bleeding a condensation turbine, or recovering steam at the exhaust of a backpressure turbine), design making the system safe. Lastly, economic considerations are dealt with: combining the production of fresh water and electric power provides usually a much better energy balance and a lower cost for both products. Examples are given of some types of installations which combine medium-size reactors with fresh water stations yielding from 10000 to 120000 m 3 per day

  17. DETECTION OF NONPOLAR IONS IN 2Π3/2 STATES BY RADIOASTRONOMY VIA MAGNETIC DIPOLE TRANSITIONS

    International Nuclear Information System (INIS)

    Morse, Michael D.; Maier, John P.

    2011-01-01

    The possibility of magnetic dipole-induced pure rotational transitions in the interstellar medium is investi- gated for symmetric Hund's case (a) linear molecules, such as H-C≡C-H + (X-tilde 2 Π 3/2u ), CO 2 + (X-tilde 2 Π 3/2g ), H-C≡C-C≡C-H + (X-tilde 2 Π 3/2g ), and N 3 (X-tilde 2 Π 3/2g ). These species lack an electric dipole moment and therefore cannot undergo pure rotational electric dipole transitions. These species can undergo pure rotational transitions via the parallel component of the magnetic dipole operator, however. The transition moments and Einstein A coefficients for the allowed pure rotational transitions are derived for a general Hund's case (a) linear molecule, and tabulated for the examples of H-C≡C-H + ( 2 Π 3/2u ) and H-C≡C-C≡C-H + ( 2 Π 3/2g ). It is found that the rates of emission are comparable to collision rates in interstellar clouds, suggesting that this decay mechanism may be important in simulating rotational population distributions in diffuse clouds and for detecting these molecules by radioastronomy. Expected line positions for the magnetic dipole-allowed R ef (J) and R fe (J) transitions of H-C≡C-H + ( 2 Π 3/2u ), H-C≡C-C≡C-H + ( 2 Π 3/2g ), CO 2 + ( 2 Π 3/2g ), and N 3 ( 2 Π 3/2g ) are tabulated to assist in their observation by radioastronomy or in the laboratory.

  18. Preparation of a Non-Polar ZnO Film on a Single-Crystal NdGaO3 Substrate by the RF Sputtering Method

    Science.gov (United States)

    Kashiwaba, Y.; Tanaka, Y.; Sakuma, M.; Abe, T.; Imai, Y.; Kawasaki, K.; Nakagawa, A.; Niikura, I.; Kashiwaba, Y.; Osada, H.

    2018-04-01

    Preparation of non-polar ZnO ( 11\\overline{2} 0 ) films on single-crystal NdGaO3 (NGO) (001) substrates was successfully achieved by the radio frequency (RF) sputtering method. Orientation, deposition rate, and surface roughness of ZnO films strongly depend on the working pressure. Characteristics of ZnO films deposited on single-crystal NGO (001) substrates were compared with those of ZnO films deposited on single-crystal sapphire ( 01\\overline{1} 2 ) substrates. An x-ray diffraction peak of the ZnO ( 11\\overline{2} 0 ) plane was observed on ZnO films deposited on single-crystal NGO (001) substrates under working pressure of less than 0.5 Pa. On the other hand, uniaxially oriented ZnO ( 11\\overline{2} 0 ) films on single-crystal sapphire ( 01\\overline{1} 2 ) substrates were observed under working pressure of 0.1 Pa. The mechanism by which the diffraction angle of the ZnO ( 11\\overline{2} 0 ) plane on single-crystal NGO (001) substrates was shifted is discussed on the basis of anisotropic stress of lattice mismatch. The deposition rate of ZnO films decreased with an increase in working pressure, and the deposition rate on single-crystal NGO (001) substrates was larger than that on single-crystal sapphire ( 01\\overline{1} 2 ) substrates. Root mean square (RMS) roughness of ZnO films increased with an increase in working pressure, and RMS roughness of ZnO films on single-crystal NGO (001) substrates was smaller than that of ZnO films on single-crystal sapphire ( 01\\overline{1} 2 ) substrates even though the film thickness on single-crystal NGO (001) substrates was greater than that on sapphire substrates. It is thought that a single-crystal NGO (001) substrate is useful for deposition of non-polar ZnO ( 11\\overline{2} 0 ) films.

  19. A potential method using Ge{iPrNC[N(SiMe_3)_2]NiPr}{sub 2}, (Et{sub 3}Si){sub 2}Te and anhydrous hydrazine for germanium tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Du, Liyong; Du, Shulei; Ding, Yuqiang [School of Chemical and Material Engineering, Jiangnan University, Wuxi (China)

    2017-12-29

    A germanium(II)-guanidine derivative of formula Ge{iPrNC[N(SiMe_3)_2]NiPr}{sub 2} (1) was synthesized and characterized by {sup 1}H NMR, {sup 13}C NMR, elemental analysis, and X-ray diffraction method. Thermal property was also studied to identify its thermal stability and volatility. More importantly, compound 1 was synthesized to develop a new method for germanium tellurides, where anhydrous hydrazine was introduced to prompt the activity of germanium(II) guanidines (or derivatives) towards (Et{sub 3}Si){sub 2}Te. Solution reaction of compound 1, (Et{sub 3}Si){sub 2}Te, and anhydrous hydrazine was investigated to pre-identify the feasibility of this combination for ALD process. The EDS data of the black precipitate from this reaction verified the potential of this method to manufacture germanium tellurides. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Tattoo: a multifaceted medium of communication

    Directory of Open Access Journals (Sweden)

    Christian Wymann

    2010-11-01

    Full Text Available This article suggests the systems theoretical distinction of form/medium as a useful tool for distinguishing social phenomena that might look as if they stem from the same process. This is shown to be the case for the tattoo and tattooing. The tattoo is conceived as a medium of communication through which different forms of communication emerge. Tattooing is one of these forms of communication that shapes the medium in a particular way. The current article sheds a special light on its intricate, communicational constellation, for which the concept of parallax is suggested. Law, medicine and cosmetics as other forms of communication use the medium of tattoo in their own way as well. The form/medium distinction allows us to grasp these different forms of communication, while it shows that they share the tattoo as medium. The article’s ultimate goal is to illustrate that the tattoo figures as a multifaceted medium of communication.

  1. Medium-Based Design: Extending a Medium to Create an Exploratory Learning Environment

    Science.gov (United States)

    Rick, Jochen; Lamberty, K. K.

    2005-01-01

    This article introduces "medium-based" design -- an approach to creating "exploratory learning environments" using the method of "extending a medium". First, the characteristics of exploratory learning environments and medium-based design are described and grounded in related work. Particular attention is given to "extending a medium" --…

  2. Dreams of a New Medium

    Directory of Open Access Journals (Sweden)

    Aden Evens

    2009-01-01

    Full Text Available Problematic at best, the desire for a transparent interface nevertheless drives much of digital culture and technology. But not the Web; or at least, not Web 1.0. Thoroughly commercialized, comfortably parsed into genres, serving billions of pages of predigested content to passive consumers, the World Wide Web as developed in the '90s unabashedly embraces its role as medium. While so many digital technologies work to hide their mediacy--drawing in the user with a total simulated sensorium, dematerializing the resistances of size and weight, untangling the knots of cables tying user to machine and machine to cubicle, minimizing the interface--Web 1.0 proudly clings to the browser as a glaring reminder of its medial character. While Web 2.0 has not forsaken the browser altogether, it nevertheless seems to offer a different sort of mediation. Arising alongside the atomization of browser functions, the ubiquitization of connectivity, and the coincidence of producer and user, Web 2.0 retains the form of a medium while reaching for the experiential logic of immediacy. This is not the immediacy of the transparent interface; rather, Web 2.0 effects an immediate relationship between the individual and culture. The interface does not disappear, but its mediacy is subsumed under the general form of cultural participation. Focusing on the "version upgrade" from Web 1.0 to 2.0, this essay will explore the implications for mediacy of this transition, noting that the fantasy of immediacy which drives Web 2.0 is layered and complex. The typical account of immediacy proposes to eliminate the interface and so construct a virtual reality (VR. But Web 2.0 mostly sidesteps the virtual, propelled instead by a fantasy of intuition in which the Web already knows what you want because it is you. Crucially, fantasies about the digital are effective: the computer's futurity inhabits our world, finding its expression in politics, advertising, budgeting, strategic planning

  3. Cathodoluminescence study of Mg activation in non-polar and semi-polar faces of undoped/Mg-doped GaN core-shell nanorods

    Science.gov (United States)

    Hortelano, V.; Martínez, O.; Cuscó, R.; Artús, L.; Jiménez, J.

    2016-03-01

    Spectrally and spatially resolved cathodoluminescence (CL) measurements were carried out at 80 K on undoped/Mg-doped GaN core-shell nanorods grown by selective area growth metalorganic vapor phase epitaxy in order to investigate locally the optical activity of the Mg dopants. A study of the luminescence emission distribution over the different regions of the nanorods is presented. We have investigated the CL fingerprints of the Mg incorporation into the non-polar lateral prismatic facets and the semi-polar facets of the pyramidal tips. The amount of Mg incorporation/activation was varied by using several Mg/Ga flow ratios and post-growth annealing treatment. For lower Mg/Ga flow ratios, the annealed nanorods clearly display a donor-acceptor pair band emission peaking at 3.26-3.27 eV and up to 4 LO phonon replicas, which can be considered as a reliable indicator of effective p-type Mg doping in the nanorod shell. For higher Mg/Ga flow ratios, a substantial enhancement of the yellow luminescence emission as well as several emission subbands are observed, which suggests an increase of disorder and the presence of defects as a consequence of the excess Mg doping.

  4. Optical properties of InN nanocolumns: Electron accumulation at InN non-polar surfaces and dependence on the growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Segura-Ruiz, J.; Cantarero, A. [Materials Science Institute, University of Valencia (Spain); Garro, N. [Materials Science Institute, University of Valencia (Spain); Fundacio General de la Universitat de Valencia, Valencia (Spain); Iikawa, F. [Instituto de Fisica ' ' Gleb Wataghin' ' , UNICAMP, Campinas-SP (Brazil); Denker, C.; Malindretos, J.; Rizzi, A. [IV. Physikalisches Institut, Georg-August Universitaet Goettingen (Germany)

    2009-06-15

    InN nanocolumns grown by plasma-assisted molecular beam epitaxy have been studied by photoluminescence (PL) and photoluminescence excitation (PLE). The PL peak energy was red-shifted with respect to the PLE onset and both energies were higher than the low temperature band-gap reported for InN. PL and PLE experiments for different excitation and detection energies indicated that the PL peaks were homogeneously broadened. This overall phenomenology has been attributed to the effects of an electron accumulation layer present at the non-polar surfaces of the InN nanocolumns. Variations in the growth conditions modify the edge of the PLE spectra and the PL peak energies evidencing that the density of free electrons can be somehow controlled by the growth parameters. It was observed that In-BEP and substrate temperature leading to shorter In diffusion lengths diminished the effects of the electron accumulation layer on the optical properties. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Optical properties of InN nanocolumns: Electron accumulation at InN non-polar surfaces and dependence on the growth conditions

    International Nuclear Information System (INIS)

    Segura-Ruiz, J.; Cantarero, A.; Garro, N.; Iikawa, F.; Denker, C.; Malindretos, J.; Rizzi, A.

    2009-01-01

    InN nanocolumns grown by plasma-assisted molecular beam epitaxy have been studied by photoluminescence (PL) and photoluminescence excitation (PLE). The PL peak energy was red-shifted with respect to the PLE onset and both energies were higher than the low temperature band-gap reported for InN. PL and PLE experiments for different excitation and detection energies indicated that the PL peaks were homogeneously broadened. This overall phenomenology has been attributed to the effects of an electron accumulation layer present at the non-polar surfaces of the InN nanocolumns. Variations in the growth conditions modify the edge of the PLE spectra and the PL peak energies evidencing that the density of free electrons can be somehow controlled by the growth parameters. It was observed that In-BEP and substrate temperature leading to shorter In diffusion lengths diminished the effects of the electron accumulation layer on the optical properties. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Stir bar sorptive extraction and liquid chromatography-tandem mass spectrometry determination of polar and non-polar emerging and priority pollutants in environmental waters.

    Science.gov (United States)

    Aparicio, Irene; Martín, Julia; Santos, Juan Luis; Malvar, José Luis; Alonso, Esteban

    2017-06-02

    An analytical method based on stir bar sorptive extraction (SBSE) was developed and validated for the determination of environmental concern pollutants in environmental waters by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Target compounds include six water and oil repellents (perfluorinated compounds), four preservatives (butylated hydroxytoluene and three parabens), two plasticizers (bisphenol A and di(2-ethylhexyl)phthalate), seven surfactants (four linear alkylbenzene sulfonates, nonylphenol and two nonylphenol ethoxylates), a flame retardant (hexabromocyclododecane), four hormones, fourteen pharmaceutical compounds, an UV-filter (2-ethylhexyl 4-methoxycinnamate) and nine pesticides. To achieve the simultaneous extraction of polar and non-polar pollutants two stir bar coatings were tested, the classic polydimethylsiloxane (PDMS) coating and the novel ethylene glycol modified silicone (EG-silicone). The best extraction recoveries were obtained using EG-silicone coating. The effects of sample pH, volume and ionic strength and extraction time on extraction recoveries were evaluated. The analytical method was validated for surface water and tap water samples. The method quantification limits ranged from 7.0ngL -1 to 177ngL -1 . The inter-day precision, expressed as relative standard deviation, was lower than 20%. Accuracy, expressed as relative recovery values, was in the range from 61 to 130%. The method was applied for the determination of the 48 target compounds in surface and tap water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. In vitro biocompatibility and proliferative effects of polar and non-polar extracts of cucurbita ficifolia on human mesenchymal stem cells.

    Science.gov (United States)

    Aristatile, Balakrishnan; Alshammari, Ghedeir M

    2017-05-01

    Cucurbita ficifolia (C. ficifolia) has been traditionally known for its medicinal properties as an antioxidant, anti-diabetic and anti-inflammatory agent. However, there has been an enduring attention towards the identification of unique method, to isolate the natural components for therapeutic applications. Our study focuses on different polar and non-polar solvents (methanol, hexane and chloroform) to extract the bioactive components from C. ficifolia (pumpkin) and to study the biocompatibility and cytotoxicity effects on human bone marrow-mesenchymal stem cells (hBM-MSCs). The extracts were screened for their effects on cytotoxicity, cell proliferation and cell cycle on the hBM-MSCs cell line. The assays demonstrated that the chloroform extract was highly biocompatible, with less cytotoxic effect, and enhanced the cell proliferation. The methanol extract did not exhibit significant cytotoxicity when compare to the control. Concordantly, the cell cycle analysis confirmed that chloroform extract enhances the proliferation at lower concentrations. On the other hand, hexane extract showed high level of cytotoxicity with apoptotic and necrotic changes in hBM-MSCs. Collectively, our data revealed that chloroform is a good candidate to extract the bioactive components from C. ficifolia. Furthermore, our results suggest that specific gravity and density of the solvent might play a crucial role in the extraction process, which warrants further investigations. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  8. Groove-type channel enhancement-mode AlGaN/GaN MIS HEMT with combined polar and nonpolar AlGaN/GaN heterostructures

    International Nuclear Information System (INIS)

    Duan Xiao-Ling; Zhang Jin-Cheng; Xiao Ming; Zhao Yi; Ning Jing; Hao Yue

    2016-01-01

    A novel groove-type channel enhancement-mode AlGaN/GaN MIS high electron mobility transistor (GTCE-HEMT) with a combined polar and nonpolar AlGaN/GaN heterostucture is presented. The device simulation shows a threshold voltage of 1.24 V, peak transconductance of 182 mS/mm, and subthreshold slope of 85 mV/dec, which are obtained by adjusting the device parameters. Interestingly, it is possible to control the threshold voltage accurately without precisely controlling the etching depth in fabrication by adopting this structure. Besides, the breakdown voltage ( V B ) is significantly increased by 78% in comparison with the value of the conventional MIS-HEMT. Moreover, the fabrication process of the novel device is entirely compatible with that of the conventional depletion-mode (D-mode) polar AlGaN/GaN HEMT. It presents a promising way to realize the switch application and the E/D-mode logic circuits. (paper)

  9. How do glycerol and dimethyl sulphoxide affect local tetrahedral structure of water around a nonpolar solute at low temperature? Importance of preferential interaction

    Science.gov (United States)

    Daschakraborty, Snehasis

    2018-04-01

    Glycerol and dimethyl sulphoxide (DMSO) have vital roles in cryoprotection of living cells, tissues, etc. The above action has been directly linked with disruption of hydrogen (H-) bond structure and dynamics of water by these cosolvents at bulk region and around various complex units, such as peptide, amino acid, protein, and lipid membrane. However, the disruption of the local structure of the water solvent around a purely hydrophobic solute is still not studied extensively. The latter is also important in the context of stabilization of protein from cold denaturation. Through all-atom molecular dynamics simulation, we have investigated the comparative effect of glycerol and DMSO on the orientational order of water around a nonpolar solute at -5 °C. A steady reduction of the tetrahedral order of water is observed at bulk (>10 Å distance from the solute) and solute interface (structure of the interfacial water more than that of the bulk water, glycerol affects the water structure almost uniformly at all regions around the solute. Furthermore, while glycerol helps to retain water molecules at the interface, DMSO significantly reduces the water content in that region. We have put forward a plausible mechanism for these contrasting roles of these cosolvents. The solute-cosolvent hydrophobic-interaction-induced orientational alignment of an interfacial cosolvent molecule determines whether the involvement of the cosolvent molecules in H-bonding with solvent water in the interface is akin to the bulk region or not.

  10. Structural TEM study of nonpolar a-plane gallium nitride grown on(112_0) 4H-SiC by organometallic vapor phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Zakharov, Dmitri N.; Liliental-Weber, Zuzanna; Wagner, Brian; Reitmeier,Zachary J.; Preble, Edward A.; Davis, Robert F.

    2005-04-05

    Conventional and high resolution electron microscopy havebeen applied for studying lattice defects in nonpolar a-plane GaN grownon a 4H-SiC substrate with an AlN buffer layer. Samples in plan-view andcross-section configurations have been investigated. Basal and prismaticstacking faults together with Frank and Shockley partial dislocationswere found to be the main defects in the GaN layers. High resolutionelectron microscopy in combination with image simulation supported Drum smodel for the prismatic stacking faults. The density of basal stackingfaults was measured to be ~;1.6_106cm-1. The densities of partialdislocations terminating I1 and I2 types of intrinsic basal stackingfaults were ~;4.0_1010cm-2 and ~;0.4_1010cm-2, respectively. The energyof the I2 stacking fault in GaN was estimated to be (40+-4) erg/cm2 basedon the separation of Shockley partial dislocations. To the best of ourknowledge, the theoretically predicted I3 basal stacking fault in GaN wasobserved experimentally for the first time.

  11. Evaluation of distribution of nonpolar extractable in the geological environment of Quaternary sediments; Hodnotenie distribucie NEL v geologickom prostredi kvarternych sedimentov

    Energy Technology Data Exchange (ETDEWEB)

    Macek, J [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra geocheomie, 84215 Bratislava (Slovakia)

    2012-04-25

    Hydrocarbons are one of the most common environmental contaminants, especially in urban areas. This paper analyzes the situation and possible eco-toxicological effects of the two plants on contamination of soil and groundwater at the model site in Bratislava. The first is the largest leak of petroleum products in Bratislava at all - the bombing of oil refineries Apollo in 1944 and the subsequent contamination of vast areas and groundwater. The second is represented by existence of a state enterprise Kovosrot, where waste containing oil material was liquidated, also a service of mechanical machinery and vehicles was carried out there. The first is located about 1 km from the area of interest; the other is right next to it. 71 soil samples from three depth levels were analyzed by the method of infrared spectroscopy and a detailed analysis of one sample of groundwater was also made. Subsequently, a distribution of non-polar extractable substances (NEL) in the rock environment was visualized on the map's reconstructed by the MapInfo Professional Program. Thanks to this it was possible to identify the originator of pollution. (authors)

  12. Selection of culture medium and conditions for the production of ...

    African Journals Online (AJOL)

    defined medium–A, defined medium-B, synthetic medium, rich medium and industrial medium) showed that the synthetic medium yielded maximum yeast biomass (12.8 g/LDCW) followed by rich medium (11.7 g/L DCW) and defined medium B ...

  13. The interstellar medium in galaxies

    CERN Document Server

    1997-01-01

    It has been more than five decades ago that Henk van de Hulst predicted the observability of the 21-cm line of neutral hydrogen (HI ). Since then use of the 21-cm line has greatly improved our knowledge in many fields and has been used for galactic structure studies, studies of the interstellar medium (ISM) in the Milky Way and other galaxies, studies of the mass distribution of the Milky Way and other galaxies, studies of spiral struc­ ture, studies of high velocity gas in the Milky Way and other galaxies, for measuring distances using the Tully-Fisher relation etc. Regarding studies of the ISM, there have been a number of instrumen­ tal developments over the past decade: large CCD's became available on optical telescopes, radio synthesis offered sensitive imaging capabilities, not only in the classical 21-cm HI line but also in the mm-transitions of CO and other molecules, and X-ray imaging capabilities became available to measure the hot component of the ISM. These developments meant that Milky Way was n...

  14. Studies in medium energy physics

    International Nuclear Information System (INIS)

    Green, A.; Hoffmann, G.W.; McDonough, J.; Purcell, M.J.; Ray, R.L.; Read, D.E.; Worn, S.D.

    1991-12-01

    This document constitutes the (1991--1992) technical progress report and continuation proposal for the ongoing medium energy nuclear physics research program supported by the US Department of Energy through special Research Grant DE-FG05-88ER40444. The experiments discussed are conducted at the Los Alamos National Laboratory's (LANL) Clinton P. Anderson Meson Physics Facility (LAMPF) and the Alternating Gradient Synchrotron (AGS) facility of the Brookhaven National Laboratory (BNL). The overall motivation for the work discussed in this document is driven by three main objectives: (1) provide hadron-nucleon and hadron-nucleus scattering data which serve to facilitate the study of effective two-body interactions, test (and possibly determine) nuclear structure, and help study reaction mechanisms and dynamics; (2) provide unique, first-of-a-kind ''exploratory'' hadron-nucleus scattering data in the hope that such data will lead to discovery of new phenomena and new physics; and (3) perform precision tests of fundamental interactions, such as rare decay searches, whose observation would imply fundamental new physics

  15. Extraction of medium chain fatty acids from organic municipal waste and subsequent production of bio-based fuels.

    Science.gov (United States)

    Kannengiesser, Jan; Sakaguchi-Söder, Kaori; Mrukwia, Timo; Jager, Johannes; Schebek, Liselotte

    2016-01-01

    This paper provides an overview on investigations for a new technology to generate bio-based fuel additives from bio-waste. The investigations are taking place at the composting plant in Darmstadt-Kranichstein (Germany). The aim is to explore the potential of bio-waste as feedstock in producing different bio-based products (or bio-based fuels). For this investigation, a facultative anaerobic process is to be integrated into the normal aerobic waste treatment process for composting. The bio-waste is to be treated in four steps to produce biofuels. The first step is the facultative anaerobic treatment of the waste in a rotting box namely percolate to generate a fatty-acid rich liquid fraction. The Hydrolysis takes place in the rotting box during the waste treatment. The organic compounds are then dissolved and transferred into the waste liquid phase. Browne et al. (2013) describes the hydrolysis as an enzymatically degradation of high solid substrates to soluble products which are further degraded to volatile fatty acids (VFA). This is confirmed by analytical tests done on the liquid fraction. After the percolation, volatile and medium chain fatty acids are found in the liquid phase. Concentrations of fatty acids between 8.0 and 31.5 were detected depending on the nature of the input material. In the second step, a fermentation process will be initiated to produce additional fatty acids. Existing microorganism mass is activated to degrade the organic components that are still remaining in the percolate. After fermentation the quantity of fatty acids in four investigated reactors increased 3-5 times. While fermentation mainly non-polar fatty acids (pentanoic to octanoic acid) are build. Next to the fermentation process, a chain-elongation step is arranged by adding ethanol to the fatty acid rich percolate. While these investigations a chain-elongation of mainly fatty acids with pair numbers of carbon atoms (acetate, butanoic and hexanoic acid) are demonstrated. After

  16. Optical illusions induced by rotating medium

    Science.gov (United States)

    Zang, XiaoFei; Huang, PengCheng; Zhu, YiMing

    2018-03-01

    Different from the traditional single-function electromagnetic wave rotators (rotate the electromagnetic wavefronts), we propose that rotating medium can be extended to optical illusions such as breaking the diffraction limit and overlapping illusion. Furthermore, the homogeneous but anisotropic rotating medium is simplified by homogeneous and isotropic positive-index materials according to the effective medium theory, which is helpful for future device fabrication. Finite element simulations for the two-dimensional case are performed to demonstrate these properties.

  17. Recordable storage medium with protected data area

    NARCIS (Netherlands)

    2005-01-01

    The invention relates to a method of storing data on a rewritable data storage medium, to a corresponding storage medium, to a corresponding recording apparatus and to a corresponding playback apparatus. Copy-protective measures require that on rewritable storage media some data must be stored which

  18. Electromagnetic Sources in a Moving Conducting Medium

    DEFF Research Database (Denmark)

    Johannsen, Günther

    1971-01-01

    The problem of an arbitrary source distribution in a uniformly moving, homogeneous, isotropic, nondispersive, conducting medium is solved. The technique used is to solve the problem in the rest system of the medium and then write the result in an appropriate four-dimensional, covariant form which...

  19. Kultivasi Scenedesmus SP. Pada Medium Air Limbah

    OpenAIRE

    Kawaroe, Mujizat

    2011-01-01

    Proses fotosintesis pada mikroalga membutuhkan CO2 dan cahaya matahari serta nutrien untuk pertumbuhannya. Kultivasi Scenedesmus sp. pada medium air limbah bertujuan guna mencukupi kebutuhan mikroalga akan nutrien dan mengurangi masukan dari bahan kimia yang terkandung dalam air limbah tersebut ke lingkungan. Kultivasi Scenedesmus sp. dilakukan selama tujuh hari pada medium air limbah industri tanpa penambahan nutri...

  20. Effective medium theory for anisotropic metamaterials

    KAUST Repository

    Zhang, Xiujuan; Wu, Ying

    2015-01-01

    -dimensional metamaterial composed of a rectangular array of elliptic cylinders and derive an effective medium theory for such a metamaterial. We find that it is possible to obtain a closed-form analytical solution for the anisotropic effective medium parameters, provided

  1. Selective medium for aerobic incubation of Campylobacter

    Science.gov (United States)

    Studies were conducted on the formulation of a selective medium that could be used to isolate Campylobacter from mixed bacterial cultures using aerobic incubation. A non-selective, basal broth medium was prepared and supplemented with Bolton, Cefex, or Skirrow antibiotic mixtures. The ability of pur...

  2. Effective medium theory for anisotropic metamaterials

    KAUST Repository

    Zhang, Xiujuan

    2015-01-20

    Materials with anisotropic material parameters can be utilized to fabricate many fascinating devices, such as hyperlenses, metasolids, and one-way waveguides. In this study, we analyze the effects of geometric anisotropy on a two-dimensional metamaterial composed of a rectangular array of elliptic cylinders and derive an effective medium theory for such a metamaterial. We find that it is possible to obtain a closed-form analytical solution for the anisotropic effective medium parameters, provided the aspect ratio of the lattice and the eccentricity of the elliptic cylinder satisfy certain conditions. The derived effective medium theory not only recovers the well-known Maxwell-Garnett results in the quasi-static regime, but is also valid beyond the long-wavelength limit, where the wavelength in the host medium is comparable to the size of the lattice so that previous anisotropic effective medium theories fail. Such an advance greatly broadens the applicable realm of the effective medium theory and introduces many possibilities in the design of structures with desired anisotropic material characteristics. A real sample of a recently theoretically proposed anisotropic medium, with a near-zero index to control the flux, is achieved using the derived effective medium theory, and control of the electromagnetic waves in the sample is clearly demonstrated.

  3. Effect of alkyl chain length on the rotational diffusion of nonpolar and ionic solutes in 1-alkyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imides.

    Science.gov (United States)

    Gangamallaiah, V; Dutt, G B

    2013-10-10

    Rotational diffusion of a nonpolar solute 9-phenylanthracene (9-PA) and a cationic solute rhodamine 110 (R110) has been examined in a series of 1-alkyl-3-methylimidazolium (alkyl = octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl) bis(trifluoromethylsulfonyl)imides to understand the influence of alkyl chain length on solute rotation. In this study, reorientation times (τr) have been measured as a function of viscosity (η) by varying the temperature (T) of the solvents. These results have been analyzed using the Stokes-Einstein-Debye (SED) hydrodynamic theory along with the ones obtained for the same solutes in 1-alkyl-3-methylimidazolium (alkyl = methyl, ethyl, propyl, butyl, and hexyl) bis(trifluoromethylsulfonyl)imides (Gangamallaiah and Dutt, J. Phys. Chem. B 2012, 116, 12819-12825). It has been noticed that the data for 9-PA and R110 follows the relation τr = A(η/T)(n) with A being the ratio of hydrodynamic volume of the solute to the Boltzmann constant and n = 1 as envisaged by the SED theory. However, upon increasing the alkyl chain length from methyl to octadecyl significant deviations from the SED theory have been observed especially from the octyl derivative onward. From methyl to octadecyl derivatives, the value of A decreases by a factor of 3 for both the solutes and n by a factor of 1.4 and 1.6 for 9-PA and R110, respectively. These observations have been rationalized by taking into consideration the organized structure of the ionic liquids, whose influence appears to be pronounced when the number of carbon atoms in the alkyl chain attached to the imidazolium cation exceeds eight.

  4. Molecular dynamics studies of InGaN growth on nonpolar (11 2 \\xAF0 ) GaN surfaces

    Science.gov (United States)

    Chu, K.; Gruber, J.; Zhou, X. W.; Jones, R. E.; Lee, S. R.; Tucker, G. J.

    2018-01-01

    We have performed direct molecular dynamics (MD) simulations of heteroepitaxial vapor deposition of I nxG a1 -xN films on nonpolar (11 2 ¯0 ) wurtzite-GaN surfaces to investigate strain relaxation by misfit-dislocation formation. The simulated growth is conducted on an atypically large scale by sequentially injecting nearly a million individual vapor-phase atoms towards a fixed GaN substrate. We apply time-and-position-dependent boundary constraints to affect the appropriate environments for the vapor phase, the near-surface solid phase, and the bulklike regions of the growing layer. The simulations employ a newly optimized Stillinger-Weber In-Ga-N system interatomic potential wherein multiple binary and ternary structures are included in the underlying density-functional theory and experimental training sets to improve the treatment of the In-Ga-N related interactions. To examine the effect of growth conditions, we study a matrix of 63 different MD-growth simulations spanning seven I nxG a1 -xN -alloy compositions ranging from x =0.0 to x =0.8 and nine growth temperatures above half the simulated melt temperature. We found a composition dependent temperature range where all kinetically trapped defects were eliminated, leaving only quasiequilibrium misfit and threading dislocations present in the simulated films. Based on the MD results obtained in this temperature range, we observe the formation of interfacial misfit and threading dislocation arrays with morphologies strikingly close to those seen in experiments. In addition, we compare the MD-observed thickness-dependent onset of misfit-dislocation formation to continuum-elasticity-theory models of the critical thickness and find reasonably good agreement. Finally, we use the three-dimensional atomistic details uniquely available in the MD-growth histories to directly observe the nucleation of dislocations at surface pits in the evolving free surface.

  5. Nonpolar a-plane GaN grown on r-plane sapphire using multilayer AlN buffer by metalorganic chemical vapor deposition

    International Nuclear Information System (INIS)

    Chiang, C.H.; Chen, K.M.; Wu, Y.H.; Yeh, Y.S.; Lee, W.I.; Chen, J.F.; Lin, K.L.; Hsiao, Y.L.; Huang, W.C.; Chang, E.Y.

    2011-01-01

    Mirror-like and pit-free non-polar a-plane (1 1 -2 0) GaN films are grown on r-plane (1 -1 0 2) sapphire substrates using metalorganic chemical vapor deposition (MOCVD) with multilayer high-low-high temperature AlN buffer layers. The buffer layer structure and film quality are essential to the growth of a flat, crack-free and pit-free a-plane GaN film. The multilayer AlN buffer structure includes a thin low-temperature-deposited AlN (LT-AlN) layer inserted into the high-temperature-deposited AlN (HT-AlN) layer. The results demonstrate that the multilayer AlN buffer structure can improve the surface morphology of the upper a-plane GaN film. The grown multilayer AlN buffer structure reduced the tensile stress on the AlN buffer layers and increased the compressive stress on the a-plane GaN film. The multilayer AlN buffer structure markedly improves the surface morphology of the a-plane GaN film, as revealed by scanning electron microscopy. The effects of various growth V/III ratios was investigated to obtain a-plane GaN films with better surface morphology. The mean roughness of the surface was 1.02 nm, as revealed by atomic force microscopy. Accordingly, the multilayer AlN buffer structure improves the surface morphology and facilitates the complete coalescence of the a-plane GaN layer.

  6. Micropropagation of Alstroemeria in liquid medium using slow release of medium components

    NARCIS (Netherlands)

    Klerk, de G.J.M.; Brugge, ter J.

    2010-01-01

    Alstroemeria rhizomes were micropropagated on semi-solid medium (AM) and in liquid medium (LM). In LM, growth was much enhanced (ca. 70%). Adequate gas exchange was crucial. This was obtained by agitation and in static medium by a sufficient large contact area of the explant and the gaseous

  7. Collaborative Manufacturing for Small-Medium Enterprises

    Science.gov (United States)

    Irianto, D.

    2016-02-01

    Manufacturing systems involve decisions concerning production processes, capacity, planning, and control. In a MTO manufacturing systems, strategic decisions concerning fulfilment of customer requirement, manufacturing cost, and due date of delivery are the most important. In order to accelerate the decision making process, research on decision making structure when receiving order and sequencing activities under limited capacity is required. An effective decision making process is typically required by small-medium components and tools maker as supporting industries to large industries. On one side, metal small-medium enterprises are expected to produce parts, components or tools (i.e. jigs, fixture, mold, and dies) with high precision, low cost, and exact delivery time. On the other side, a metal small- medium enterprise may have weak bargaining position due to aspects such as low production capacity, limited budget for material procurement, and limited high precision machine and equipment. Instead of receiving order exclusively, a small-medium enterprise can collaborate with other small-medium enterprise in order to fulfill requirements high quality, low manufacturing cost, and just in time delivery. Small-medium enterprises can share their best capabilities to form effective supporting industries. Independent body such as community service at university can take a role as a collaboration manager. The Laboratory of Production Systems at Bandung Institute of Technology has implemented shared manufacturing systems for small-medium enterprise collaboration.

  8. Photonic-resonant left-handed medium

    International Nuclear Information System (INIS)

    Shen Jianqi

    2006-01-01

    A new scheme to realize simultaneously negative permittivity and permeability in a coherent atomic vapor medium (photonic-resonant material) via a coherent driving mechanism is suggested. It is verified that the atomic system coherently driven by a strong optical field will give rise to a negative refractive index in certain probe frequency ranges. One of the most remarkable features of the present scheme is such that a slab fabricated by the left-handed vapor medium is an ideal candidate for designing perfect lenses since the photonic-resonant atomic vapor cannot only exhibit an isotropic negative refractive index, but also provide a good impedance match at the air-medium interfaces

  9. Physical processes in the interstellar medium

    CERN Document Server

    Spitzer, Lyman

    2008-01-01

    Physical Processes in the Interstellar Medium discusses the nature of interstellar matter, with a strong emphasis on basic physical principles, and summarizes the present state of knowledge about the interstellar medium by providing the latest observational data. Physics and chemistry of the interstellar medium are treated, with frequent references to observational results. The overall equilibrium and dynamical state of the interstellar gas are described, with discussions of explosions produced by star birth and star death and the initial phases of cloud collapse leading to star formation.

  10. Optimization of medium composition for apple rootstocks

    African Journals Online (AJOL)

    User

    2011-05-02

    May 2, 2011 ... Key words: Apple rootstocks, medium composition, multiplication rate, plant growth regulators (PGRs). ... be extrapolated with the same success for another .... Analysis System (SAS) software program (SAS Institute Inc. 1999).

  11. Jet multiplicity distributions: medium dependence in MLLA

    International Nuclear Information System (INIS)

    Armesto, Nestor; Pajares, Carlos; Quiroga-Arias, Paloma

    2009-01-01

    We study the medium dependence of the multiplicity distributions in the modified leading logarithmic approximation. We focus in the enhancement in the number of branchings as the partons travel trough a dense medium created in a heavy-ion collision. We study the effect of a higher number of splittings in some jet observables by introducing the medium as a constant (f med ) in the splitting functions. Having as our ansatz for the quark and gluon jets mean multiplicities left angle n G right angle =e γy and left angle n Q right angle =r -1 e γy , we study in an analytic approach the dependence with the medium (f med ) of the anomalous dimension (γ), the multiplicity ratio (r), and so the mean multiplicities. We also obtain the higher-order moments of the multiplicity distribution, what allows us to study its dispersion. (orig.)

  12. Optimization of medium composition for thermostable protease ...

    African Journals Online (AJOL)

    SERVER

    2008-04-17

    Apr 17, 2008 ... Optimization of the fermentation medium for maximization of thermostable neutral protease production by Bacillus sp. ..... Each contour curve represented an infinite number of combinations of two ..... Production in sea-water of.

  13. Fractional diffusion equation for heterogeneous medium

    International Nuclear Information System (INIS)

    Polo L, M. A.; Espinosa M, E. G.; Espinosa P, G.; Del Valle G, E.

    2011-11-01

    The asymptotic diffusion approximation for the Boltzmann (transport) equation was developed in 1950 decade in order to describe the diffusion of a particle in an isotropic medium, considers that the particles have a diffusion infinite velocity. In this work is developed a new approximation where is considered that the particles have a finite velocity, with this model is possible to describe the behavior in an anomalous medium. According with these ideas the model was obtained from the Fick law, where is considered that the temporal term of the current vector is not negligible. As a result the diffusion equation of fractional order which describes the dispersion of particles in a highly heterogeneous or disturbed medium is obtained, i.e., in a general medium. (Author)

  14. Small and medium power reactors 1987

    International Nuclear Information System (INIS)

    1987-12-01

    This TECDOC follows the publication of TECDOC-347 Small and Medium Power Reactors Project Initiation Study - Phase I published in 1985 and TECDOC-376 Small and Medium Power Reactors 1985 published in 1986. It is mainly intended for decision makers in Developing Member States interested in embarking on a nuclear power programme. It consists of two parts: 1) Guidelines for the Introduction of Small and Medium Power Reactors in Developing Countries. These Guidelines were established during the Advisory Group Meeting held in Vienna from 11 to 15 May 1987. Their purpose is to review key aspects relating to the introduction of Small and Medium Power Reactors in developing countries; 2) Up-dated Information on SMPR Concepts Contributed by Supplier Industries. According to the recommendations of the Second Technical Committee Meeting on SMPRs held in Vienna in March 1985, this part contains the up-dated information formerly published in Annex I of the above mentioned TECDOC-347. Figs

  15. Incompatibility of Contrast Medium and Trisodium Citrate

    International Nuclear Information System (INIS)

    Delcour, Christian; Bruninx, Guy

    2013-01-01

    To test the compatibility of trisodium citrate, a catheter lock solution, with iodinated contrast medium. Iohexol, iobitridol, iodixanol, ioxaglate, ioxithalamate, iomeprol, and iopromide were tested. In all tests, 2 ml of contrast medium were mixed with 2 ml of trisodium citrate solution. Iodixanol and ioxaglate provoked a highly viscous gluelike precipitation when mixed with trisodium citrate. A brief transient precipitate was observed with iohexol, iomeprol, and ioxithalamate. Permanent precipitation occurred with iobitridol and iopromide. One must be aware of the potential for precipitation when contrast medium is mixed with trisodium citrate solution. Before trisodium citrate solution is injected, the catheter should be thoroughly flushed with saline if a contrast medium has previously been injected through it.

  16. Study of niobium corrosion in alkaline medium

    International Nuclear Information System (INIS)

    Almeida, S.H. de.

    1987-01-01

    A comparative study of niobium electrochemical behaviour in NaOH and KOH solution, with concentrations between 0,5 and 6,1M is presented. The studies were done through electrochemicals assays, consisting in the corrosion potential and anodic and cathodic polarization curves, complemented by loss of mass experiments. The niobium anodic behaviour in alkaline medium is characterized by passivation occurrence, with a stable film formation. The Na oH solution in alkaline medium are more corrosible to niobium than the KOH solution. The loss of mass assays showed that the corrosion velocit is more dependente of hydroxide concentration in KOH medium than the NaOH medium. (C.G.C.) [pt

  17. Small and Medium Enterprises and Biopharmaceutical Innovations ...

    African Journals Online (AJOL)

    Erah

    Benin City, 300001 Nigeria. All rights ... are challenges facing African Small and Medium Enterprises (SMEs) in biopharmaceutical industry, the ... Network for Drug and Diagnostics recognizes .... functionality is in place, integration into the.

  18. Sharing perspectives on English-medium instruction

    CERN Document Server

    Ackerley, Katherine; Helm, Francesca

    2017-01-01

    This volume gives voice to the views and experiences of researchers, lecturers, administrative staff, teacher trainers and students with regard to the implementation of English-medium instruction in a public university based in the north-east of Italy.

  19. Medium Effects in Reactions with Rare Isotopes

    International Nuclear Information System (INIS)

    Bertulani, C A; Karakoç, M

    2012-01-01

    We discuss medium effects in knockout reactions with rare isotopes of weakly-bound nuclei at intermediate energies. We show that the poorly known corrections may lead to sizable modifications of knockout cross sections and momentum dsitributions.

  20. Effective medium theory principles and applications

    CERN Document Server

    Choy, Tuck C

    2015-01-01

    Effective medium theory dates back to the early days of the theory of electricity. Faraday in 1837 proposed one of the earliest models for a composite metal-insulator dielectric and around 1870 Maxwell and later Garnett (1904) developed models to describe a composite or mixed material medium. The subject has been developed considerably since and while the results are useful for predicting materials performance, the theory can also be used in a wide range of problems in physics and materials engineering. This book develops the topic of effective medium theory by bringing together the essentials of both the static and the dynamical theory. Electromagnetic systems are thoroughly dealt with, as well as related areas such as the CPA theory of alloys, liquids, the density functional theory etc., with applications to ultrasonics, hydrodynamics, superconductors, porous media and others, where the unifying aspects of the effective medium concept are emphasized. In this new second edition two further chapters have been...

  1. Small and medium power reactors 1987

    Science.gov (United States)

    1987-12-01

    This TECDOC follows the publication of TECDOC-347: Small and Medium Power Reactors (SMPR) Project Initiation Study, Phase 1, published in 1985 and TECDOC-376: Small and Medium Power Reactors 1985 published in 1986. It is mainly intended for decision makers in Developing Member States interested in embarking on a nuclear power program. It consists of two parts: (1) guidelines for the introduction of small and medium power reactors in developing countries. These Guidelines were established during the Advisory Group Meeting held in Vienna from 11 to 15 May 1987. Their purpose is to review key aspects relating to the introduction of small and medium power reactors in developing countries; (2) up-dated information on SMPR Concepts Contributed by Supplier Industries. According to the recommendations of the Second Technical Committee Meeting on SMPRs held in Vienna in March 1985, this part contains the up-dated information formerly published in Annex 1 of the above mentioned TECDOC-347.

  2. Switching power converters medium and high power

    CERN Document Server

    Neacsu, Dorin O

    2013-01-01

    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  3. Nonpolar organic compounds as PM2.5 source tracers: Investigation of their sources and degradation in the Pearl River Delta, China

    Science.gov (United States)

    Wang, Qiongqiong; Feng, Yongming; Huang, X. H. Hilda; Griffith, Stephen M.; Zhang, Ting; Zhang, Qingyan; Wu, Dui; Yu, Jian Zhen

    2016-10-01

    A group of nonpolar organic compounds (NPOCs) in five compound classes including alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, and 1,3,5-triphenylbenzene were quantified in samples of particulate matter of aerodynamic diameter less than 2.5 μm collected at four sites in the Pearl River Delta (PRD) region, China, over a 2 year period from 2011 to 2012. The four sites include industrial (Nanhai), urban (Guangzhou), urban outskirt (Dongguan), and suburban (Nansha) locations. Some NPOCs are uniquely emitted from particular combustion sources and thereby serving as markers in source apportionment. Based on this multiyear and multisite NPOC data set, spatial and seasonal variations, correlation analysis, and ratio-ratio plots were used to investigate the source information and degradation of NPOC tracers. In summer, NPOCs showed distinct local emission characteristics, with urban sites having much higher concentrations than suburban sites. In winter, regional transport was an important influence on NPOC levels, driving up concentrations at all sampling sites and diminishing an urban-suburban spatial gradient. The lighter NPOCs exhibited more prominent seasonal variations. Such spatiotemporal features suggest that their particle-phase abundance is more influenced by temperature, which is a critical factor in controlling the extent of semivolatile organics partitioned into the aerosol phase. The heavier NPOCs, especially PAHs, showed negligible correlation among the four sites, suggesting more influence from local emissions. Ratio-ratio plots indicate photodegradation and mixing of various sources for the NPOCs in the PRD. A positive matrix factorization (PMF) analysis of this large NPOC data set suggests that heavier NPOCs are more suitable source indicators than lighter NPOCs. Incorporating particle-phase light NPOC concentrations in PMF produces a separate factor, which primarily contains those light NPOCs and likely is not a source factor. Total

  4. Non-polar organic compounds as PM2.5 source tracers: Investigation of their sources and degradation in the Pearl River Delta, China

    Science.gov (United States)

    Wang, Q.; Feng, Y.; Huang, X. H. H.; Griffith, S.; Zhang, T.; Zhang, Q.; Wu, D.; Yu, J.

    2016-12-01

    Nonpolar organic compounds (NPOCs) including alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, and 1,3,5-triphenylbenzene, were quantified in PM2.5 samples at four sites in the Pearl River Delta (PRD) region, China over a two-year period from 2011 to 2012. The four sites include one industrial zone (Nanhai), one urban (Guangzhou), one urban outskirt (Dongguan) and one suburban (Nansha) locations. Some NPOCs are uniquely emitted from particular combustion sources, and thereby serving as convenient markers in source apportionment. Based on this multi-year and multi-site data set, spatial and seasonal variations, correlation analysis and ratio-ratio plots were used to investigate the source information and degradation of NPOC tracers. In summer, NPOCs showed distinct local emission characteristics, with urban sites having much higher concentrations than suburban site. In winter, regional transport was an important influence on NPOC levels, driving up concentrations at all sampling sites and diminishing an urban-suburban spatial gradient. The lighter NPOCs exhibited more prominent seasonal variations, suggesting their particle-phase abundance is more influenced by temperature, a critical factor in controlling the extent of semi-volatile organics partitioned into the aerosol phase. The heavier NPOCs, especially PAHs, showed negligible correlation among the four sites, suggesting more influence from local emissions. Ratio-ratio plots indicate photo-degradation and mixing of various sources for the NPOCs in the PRD. A positive matrix factorization (PMF) analysis of this large NPOC data set suggests that heavier NPOCs are more suitable source indicators than lighter NPOCs. Incorporating particle-phase light NPOC concentrations in PMF produces a separate factor, which primarily contains those light NPOCs and likely is not a source factor. Total NPOC concentrations predicted using Pankow partitioning theory were explored as PMF inputs, however, the PMF

  5. Microsolvation of the acetanilide cation (AA(+)) in a nonpolar solvent: IR spectra of AA(+)-L(n) clusters (L = He, Ar, N2; n ≤ 10).

    Science.gov (United States)

    Schmies, Matthias; Patzer, Alexander; Schütz, Markus; Miyazaki, Mitsuhiko; Fujii, Masaaki; Dopfer, Otto

    2014-05-07

    Infrared photodissociation (IRPD) spectra of mass-selected cluster ions of acetanilide (N-phenylacetamide), AA(+)-Ln, with the ligands L = He (n = 1-2), Ar (n = 1-7), and N2 (n = 1-10) are recorded in the hydride stretch (amide A, νNH, νCH) and fingerprint (amide I-III) ranges of AA(+) in its (2)A'' ground electronic state. Cold AA(+)-Ln clusters are generated in an electron impact ion source, which predominantly produces the most stable isomer of a given cluster ion. Systematic vibrational frequency shifts of the N-H stretch fundamentals (νNH) provide detailed information about the sequential microsolvation process of AA(+) in a nonpolar (L = He and Ar) and quadrupolar (L = N2) solvent. In the most stable AA(+)-Ln clusters, the first ligand forms a hydrogen bond (H-bond) with the N-H proton of trans-AA(+) (t-AA(+)), whereas further ligands bind weakly to the aromatic ring (π-stacking). There is no experimental evidence for complexes with the less stable cis-AA(+) isomer. Quantum chemical calculations at the M06-2X/aug-cc-pVTZ level confirm the cluster growth sequence derived from the IR spectra. The calculated binding energies of De(H) = 720 and 1227 cm(-1) for H-bonded and De(π) = 585 and 715 cm(-1) for π-bonded Ar and N2 ligands in t-AA(+)-L are consistent with the observed photofragmentation branching ratios of AA(+)-Ln. Comparison between charged and neutral AA((+))-L dimers indicates that ionization switches the preferred ion-ligand binding motif from π-stacking to H-bonding. Electron removal from the HOMO of AA(+) delocalized over both the aromatic ring and the amide group significantly strengthens the C[double bond, length as m-dash]O bond and weakens the N-H bond of the amide group.

  6. DYNAMIC DEFORMATION THE VISCOELASTIC TWOCOMPONENT MEDIUM

    Directory of Open Access Journals (Sweden)

    V. S. Polenov

    2015-01-01

    Full Text Available Summary. In the article are scope harmonious warping of the two-component medium, one component which are represent viscoelastic medium, hereditary properties which are described by the kernel aftereffect Abel integral-differential ratio BoltzmannVolterr, while second – compressible liquid. Do a study one-dimensional case. Use motion equation of two-component medium at movement. Look determination system these equalization in the form of damped wave. Introduce dimensionless coefficient. Combined equations happen to homogeneous system with complex factor relatively waves amplitude in viscoelastic component and in fluid. As a result opening system determinant receive biquadratic equation. Elastic operator express through kernel aftereffect Abel for space Fourier. With the help transformation and symbol series biquadratic equation reduce to quadratic equation. Come to the conclusion that in two-component viscoelastic medium exist two mode sonic waves. As a result solution of quadratic equation be found description advance of waves sonic in viscoelastic two-component medium, which physical-mechanical properties represent complex parameter. Velocity determination advance of sonic waves, attenuation coefficient, mechanical loss tangent, depending on characteristic porous medium and circular frequency formulas receive. Graph dependences of description advance of waves sonic from the temperature logarithm and with the fractional parameter γ are constructed.

  7. Selective medium for culture of Mycoplasma hyopneumoniae.

    Science.gov (United States)

    Cook, Beth S; Beddow, Jessica G; Manso-Silván, Lucía; Maglennon, Gareth A; Rycroft, Andrew N

    2016-11-15

    The fastidious porcine respiratory pathogen Mycoplasma hyopneumoniae has proven difficult to culture since it was first isolated in 1965. A reliable solid medium has been particularly challenging. Moreover, clinical and pathological samples often contain the fast-growing M. hyorhinis which contaminates and overgrows M. hyopneumoniae in primary culture. The aim of this study was to optimise the culture medium for recovery of M. hyopneumoniae and to devise a medium for selection of M. hyopneumoniae from clinical samples also containing M. hyorhinis. The solid medium devised by Niels Friis was improved by use of Purified agar and incorporation of DEAE-dextran. Addition of glucose or neutralization of acidity in liquid medium with NaOH did not improve the final yield of viable organisms or alter the timing of peak viability. Analysis of the relative susceptibility of M. hyopneumoniae and M. hyorhinis strains to four antimicrobials showed that M. hyopneumoniae is less susceptible than M. hyorhinis to kanamycin. This was consistent in all UK and Danish strains tested. A concentration of 2μg/ml of kanamycin selectively inhibited the growth of all M. hyorhinis tested, while M. hyopneumoniae was able to grow. This forms the basis of an effective selective culture medium for M. hyopneumoniae. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Natural gas adsorption on coal in anhydrous and in water saturated conditions: study of the adsorbed quantities and of the isotopic fractionation

    International Nuclear Information System (INIS)

    Caja, M.

    2000-02-01

    In order to understand the influence of adsorption in the migration of natural gas in sedimentary basins. we have developed an experimental device to measure the quantity of gas adsorbed on organic matter. We quantify the isotopic and chemical fractionation due to adsorption of natural gas on coal at representative gas field conditions (20 - 200 deg C and 1 - 1000 bar). These effects are investigated for gas / solid systems and for gas dissolved in water/water saturated solid systems. The solid sample considered in this work is a natural coal of Carboniferous age, taken from a mine in Lorraine, France. Its maturity corresponds to the end of the diagenesis zone. A first set of high pressure methane adsorption experiments on dry coal are compared with measurements done by another laboratory on the same solid. This allowed us to validate the experimental procedure. This measurements performed in the presence of water have shown that methane adsorption is significant even in presence of water. We have developed a simple adsorption model (Langmuir model in which fugacity is used in stead of partial pressure) in order to represent this phenomena. For a depth profile we compare the part of methane adsorbed on sedimentary rocks organic matter to methane dissolved in pore water. A second set of experiments realised on a multicomponent gas (C1, C2, C3, C4, CO 2 ) shows a preferential adsorption of carbon dioxide, but no significant fractionation on hydrocarbon gases of the mixture has been observed. Adsorption experiments of methane on dry medium and on water saturated medium yield on the same result: adsorption equilibrium do not induce a significant isotopic fractionation between 13 CH 4 and 12 CH 4 . However, we observe a significant fractionation during gas desorption. The interpretation is that we are not at equilibrium and diffusion phenomena is superimposed on adsorption. From this study two important geological consequences can be drawn. First. for rocks containing

  9. Overview of medium heterogeneity and transport processes

    International Nuclear Information System (INIS)

    Tsang, Y.; Tsang, C.F.

    1993-11-01

    Medium heterogeneity can have significant impact on the behavior of solute transport. Tracer breakthrough curves from transport in a heterogeneous medium are distinctly different from that in a homogeneous porous medium. Usually the shape of the breakthrough curves are highly non-symmetrical with a fast rise at early times and very long tail at late times, and often, they consist of multiple peaks. Moreover, unlike transport in a homogeneous medium where the same transport parameters describe the entire medium, transport through heterogeneous media gives rise to breakthrough curves which have strong spatial dependence. These inherent characteristics of transport in heterogeneous medium present special challenge to the performance assessment of a potential high level nuclear waste repository with respect to the possible release of radio nuclides to the accessible environment. Since an inherently desirable site characteristic for a waste repository is that flow and transport should be slow, then transport measurements in site characterization efforts will necessarily be spatially small and temporally short compare to the scales which are of relevance to performance assessment predictions. In this paper we discuss the role of medium heterogeneity in site characterization and performance assessment. Our discussion will be based on a specific example of a 3D heterogeneous stochastic model of a site generally similar to, the Aespoe Island, the site of the Hard Rock Laboratory in Southern Sweden. For our study, alternative 3D stochastic fields of hydraulic conductivities conditioned on ''point'' measurements shall be generated. Results of stochastic flow and transport simulations would be used to address the issues of (1) the relationship of tracer breakthrough with the structure of heterogeneity, and (2) the inference from small scale testing results to large scale and long term predictions

  10. Evaluation of Insulin Medium or Chondrogenic Medium on Proliferation and Chondrogenesis of ATDC5 Cells

    OpenAIRE

    Yao, Yongchang; Zhai, Zhichen; Wang, Yingjun

    2014-01-01

    Background. The ATDC5 cell line is regarded as an excellent cell model for chondrogenesis. In most studies with ATDC5 cells, insulin medium (IM) was used to induce chondrogenesis while chondrogenic medium (CM), which was usually applied in chondrogenesis of mesenchymal stem cells (MSCs), was rarely used for ATDC5 cells. This study was mainly designed to investigate the effect of IM, CM, and growth medium (GM) on chondrogenesis of ATDC5 cells. Methods. ATDC5 cells were, respectively, cultured ...

  11. 'That proves my point': How mediums reconstrue disconfirmation in medium-sitter interactions.

    Science.gov (United States)

    Enoksen, Anette Einan; Dickerson, Paul

    2018-04-01

    Previous research has examined how the talk of mediums attends to the epistemological status of their readings. Such work has identified that mediums frequently use question-framed propositions that are typically confirmed by the sitter, thereby conferring epistemological status on the medium. This study seeks to investigate what happens when the sitter disconfirms the propositions of the medium. The study focuses on the ways in which such disconfirmation can be responded to such that it is reconstrued as evidence of the psychic nature of the medium's reading. Televised demonstrations of psychic readings involving British and US mediums and their sitters are analysed. The results suggest that mediums rework disconfirmation as proof in several ways: first, by emphasizing the different access that sitter and medium have to knowledge (e.g., about the future); second, as evidence that the medium has access to the actual voice of the deceased (and may therefore mishear what the deceased has said to them); and third, as revealing an important truth that has hitherto been concealed from the sitter. The implications of these findings are considered for cases where speakers bring different and potentially competing, epistemological resources to an interaction. © 2018 The British Psychological Society.

  12. Enhancement of catalytic efficiency of enzymes through exposure to anhydrous organic solvent at 70 degrees C. Three-dimensional structure of a treated serine proteinase at 2.2 A resolution.

    Science.gov (United States)

    Gupta, M N; Tyagi, R; Sharma, S; Karthikeyan, S; Singh, T P

    2000-05-15

    The enzyme behavior in anhydrous media has important applications in biotechnology. So far chemical modifications and protein engineering have been used to alter the catalytic power of the enzymes. For the first time, it is demonstrated that an exposure of enzyme to anhydrous organic solvents at optimized high temperature enhances its catalytic power through local changes at the binding region. Six enzymes: proteinase K, wheat germ acid phosphatase, alpha-amylase, beta-glucosidase, chymotrypsin and trypsin have been exposed to acetonitrile at 70 degrees C for three hours. The activities of these enzymes were found to be considerably enhanced. In order to understand the basis of this change in the activity of these enzymes, the structure of one of these treated enzymes, proteinase K has been analyzed in detail using X-ray diffraction method. The overall structure of the enzyme is similar to the native structure in aqueous environment. The hydrogen bonding system of the catalytic triad is intact after the treatment. However, the water structure in the substrate binding site undergoes some rearrangement as some of the water molecules are either displaced or completely absent. The most striking observation concerning the water structure pertains to the complete deletion of the water molecule which occupied the position at the so-called oxyanion hole in the active site of the native enzyme. Three acetonitrile molecules were found in the present structure. All the acetonitrile molecules are located in the recognition site. The sites occupied by acetonitrile molecules are independent of water molecules. The acetonitrile molecules are involved in extensive interactions with the protein atoms. All of them are interlinked through water molecules. The methyl group of one of the acetonitrile molecules (CCN1) interacts simultaneously with the hydrophobic side chains of Leu-96, Ile-107, and Leu-133. The development of such a hydrophobic environment at the recognition site

  13. CHROMagar Orientation Medium Reduces Urine Culture Workload

    Science.gov (United States)

    Manickam, Kanchana; Karlowsky, James A.; Adam, Heather; Lagacé-Wiens, Philippe R. S.; Rendina, Assunta; Pang, Paulette; Murray, Brenda-Lee

    2013-01-01

    Microbiology laboratories continually strive to streamline and improve their urine culture algorithms because of the high volumes of urine specimens they receive and the modest numbers of those specimens that are ultimately considered clinically significant. In the current study, we quantitatively measured the impact of the introduction of CHROMagar Orientation (CO) medium into routine use in two hospital laboratories and compared it to conventional culture on blood and MacConkey agars. Based on data extracted from our Laboratory Information System from 2006 to 2011, the use of CO medium resulted in a 28% reduction in workload for additional procedures such as Gram stains, subcultures, identification panels, agglutination tests, and biochemical tests. The average number of workload units (one workload unit equals 1 min of hands-on labor) per urine specimen was significantly reduced (P < 0.0001; 95% confidence interval [CI], 0.5326 to 1.047) from 2.67 in 2006 (preimplementation of CO medium) to 1.88 in 2011 (postimplementation of CO medium). We conclude that the use of CO medium streamlined the urine culture process and increased bench throughput by reducing both workload and turnaround time in our laboratories. PMID:23363839

  14. Rotational diffusion of nonpolar and ionic solutes in 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides: is solute rotation always influenced by the length of the alkyl chain on the imidazolium cation?

    Science.gov (United States)

    Gangamallaiah, V; Dutt, G B

    2012-10-25

    In an attempt to find out whether the length of the alkyl chain on the imidazolium cation has a bearing on solute rotation, temperature-dependent fluorescence anisotropies of three structurally similar solutes have been measured in a series of 1-alkyl-3-methylimidazolium (alkyl = methyl, ethyl, propyl, butyl, and hexyl) bis(trifluoromethylsulfonyl)imides. Solute-solvent coupling constants obtained from the experimentally measured reorientation times with the aid of Stokes-Einstein-Debye hydrodynamic theory indicate that there is no influence of the length of the alkyl chain on the rotation of nonpolar, anionic, and cationic solutes 9-phenylanthracene (9-PA), fluorescein (FL), and rhodamine 110 (R110), respectively. It has also been noticed that the rotational diffusion of 9-PA is closer to the predictions of slip hydrodynamics, whereas the rotation of negatively charged FL and positively charged R110 is almost identical and follows stick hydrodynamics in these ionic liquids. Despite having similar shape and size, ionic solutes rotate slower by a factor of 3-4 compared to the nonpolar solute. Interplay of specific and electrostatic interactions between FL and the imidazolium cation of the ionic liquids, and between R110 and the bis(trifluoromethylsulfonyl)imide anion, appear to be responsible for the observed behavior. These results are an indication that the length of the alkyl chain on the imidazolium cation does not alter their physical properties in a manner that has an effect on solute rotation.

  15. High-quality nonpolar a-plane GaN epitaxial films grown on r-plane sapphire substrates by the combination of pulsed laser deposition and metal–organic chemical vapor deposition

    Science.gov (United States)

    Yang, Weijia; Zhang, Zichen; Wang, Wenliang; Zheng, Yulin; Wang, Haiyan; Li, Guoqiang

    2018-05-01

    High-quality a-plane GaN epitaxial films have been grown on r-plane sapphire substrates by the combination of pulsed laser deposition (PLD) and metal–organic chemical vapor deposition (MOCVD). PLD is employed to epitaxial growth of a-plane GaN templates on r-plane sapphire substrates, and then MOCVD is used. The nonpolar a-plane GaN epitaxial films with relatively small thickness (2.9 µm) show high quality, with the full-width at half-maximum values of GaN(11\\bar{2}0) along [1\\bar{1}00] direction and GaN(10\\bar{1}1) of 0.11 and 0.30°, and a root-mean-square surface roughness of 1.7 nm. This result is equivalent to the quality of the films grown by MOCVD with a thickness of 10 µm. This work provides a new and effective approach for achieving high-quality nonpolar a-plane GaN epitaxial films on r-plane sapphire substrates.

  16. Nonpolar a-plane light-emitting diode with an in-situ SiNx interlayer on r-plane sapphire grown by metal-organic chemical vapour deposition

    International Nuclear Information System (INIS)

    Fang Hao; Long Hao; Sang Li-Wen; Qi Sheng-Li; Xiong Chang; Yu Tong-Jun; Yang Zhi-Jian; Zhang Guo-Yi

    2011-01-01

    We report on the growth and fabrication of nonpolar a-plane light emitting diodes with an in-situ SiN x interlayer grown between the undoped a-plane GaN buffer and Si-doped GaN layer. X-ray diffraction shows that the crystalline quality of the GaN buffer layer is greatly improved with the introduction of the SiN x interlayer. The electrical properties are also improved. For example, electron mobility and sheet resistance are reduced from high resistance to 31.6 cm 2 /(V·s) and 460 Ω/□ respectively. Owing to the significant effect of the SiN x interlayer, a-plane LEDs are realized. Electroluminescence of a nonpolar a-plane light-emitting diode with a wavelength of 488nm is demonstrated. The emission peak remains constant when the injection current increases to over 20 mA. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  17. Hadrons in hot and dense medium

    International Nuclear Information System (INIS)

    Mallik, S.

    2004-01-01

    We review chiral perturbation theory in some detail and construct interaction terms involving the Goldstone and the different non-Goldstone fields, in presence of external (classical) fields coupled to currents. The ensemble average of the two-point functions of the currents can now be expanded in terms of Feynman diagrams. We evaluate the one-loop diagrams in the neighbourhood of the respective poles to find the effective couplings and masses of the particles in medium. We also describe the virial formula for the self-energy of a particle in medium, giving its pole position. It proves useful if the scattering amplitude of the particle with particles in medium is known experimentally. (author)

  18. Charmonium propagation through a dense medium

    Directory of Open Access Journals (Sweden)

    Kopeliovich B.Z.

    2015-01-01

    Full Text Available Attenuation of a colourless c̄c dipole propagating with a large momentum through a hot medium originates from two sources, Debye screening (melting, and inelastic collisions with surrounding scattering centres (absorption. The former never terminates completely production of a bound charmonium in heavy ion collisions, even at very high temperatures. The latter, is controlled my the magnitude of the dipole cross section, related to the transport coefficient, which is the rate of transverse momentum broadening in the medium. A novel procedure of Lorentz boosting of the Schrödinger equation is developed, which allows to calculate the charmonium survival probability employing the path-integral technique, incorporating both melting and absorption. A novel mechanism of charmonium regeneration in a dense medium is proposed.

  19. Coherent neutrino interactions in a dense medium

    International Nuclear Information System (INIS)

    Kiers, K.; Weiss, N.

    1997-01-01

    Motivated by the effect of matter on neutrino oscillations (the MSW effect) we study in more detail the propagation of neutrinos in a dense medium. The dispersion relation for massive neutrinos in a medium is known to have a minimum at nonzero momentum p∼G F ρ/√(2). We study in detail the origin and consequences of this dispersion relation for both Dirac and Majorana neutrinos both in a toy model with only neutral currents and a single neutrino flavor and in a realistic open-quotes standard modelclose quotes with two neutrino flavors. We find that for a range of neutrino momenta near the minimum of the dispersion relation, Dirac neutrinos are trapped by their coherent interactions with the medium. This effect does not lead to the trapping of Majorana neutrinos. copyright 1997 The American Physical Society

  20. Temperature distribution in a uniformly moving medium

    International Nuclear Information System (INIS)

    Mitchell, Joseph D; Petrov, Nikola P

    2009-01-01

    We apply several physical ideas to determine the steady temperature distribution in a medium moving with uniform velocity between two infinite parallel plates. We compute it in the coordinate frame moving with the medium by integration over the 'past' to account for the influence of an infinite set of instantaneous point sources of heat in past moments as seen by an observer moving with the medium. The boundary heat flux is simulated by appropriately distributed point heat sources on the inner side of an adiabatically insulating boundary. We make an extensive use of the Green functions with an emphasis on their physical meaning. The methodology used in this paper is of great pedagogical value as it offers an opportunity for students to see the connection between powerful mathematical techniques and their physical interpretation in an intuitively clear physical problem. We suggest several problems and a challenging project that can be easily incorporated in undergraduate or graduate courses

  1. Graphene wire medium: Homogenization and application

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Chigrin, Dmitry N.; Lavrinenko, Andrei

    2012-01-01

    In this contribution we analyze numerically the optical properties of the graphene wire medium, which unit cell consists of a stripe of graphene embedded into dielectric. We propose a simple method for retrieval of the isofrequency contour and effective permittivity tensor. As an example of the g......In this contribution we analyze numerically the optical properties of the graphene wire medium, which unit cell consists of a stripe of graphene embedded into dielectric. We propose a simple method for retrieval of the isofrequency contour and effective permittivity tensor. As an example...... of the graphene wire medium application we demonstrate a reconfigurable hyperlens for the terahertz subwavelength imaging capable of resolving two sources with separation λ0/5 in the far-field....

  2. Small and medium size nuclear reactors

    International Nuclear Information System (INIS)

    Al-Mugrabi, M.A.

    1996-01-01

    The purpose of this appendix is to provide up-to-date technical information relevant to the deployment of small and medium reactors (SMRs). It summarizes the status of SMRs and discusses areas of relevance to their utilization, including seawater desalination; and in particular their simplicity, their flexibility for a variety of applications and the use of passive safety features as fundamental to most of these designs. In response to important commercial developments, the energy range of small and medium reactors is now taken as being up to around 700 MW(e). Detailed information on SMR designs can be found in the IAEA report on The Design and Development Status of Small and Medium Reactor Systems 1995. 5 refs, 2 figs, 1 tab

  3. H2 molecules and the intercloud medium

    International Nuclear Information System (INIS)

    Hill, J.K.; Hollenbach, D.J.

    1976-01-01

    We discuss expected column of densities of H 2 in the intercloud medium and the possible use of molecules as indicators of intercloud physical conditions. We treat molecule formation by the H - process and on graphite grains and show that the Barlow-Silk hypothesis of a 1 eV semichemical hydrogen-graphite bond leads to a large enhancement of the intercloud molecule formation rate. Rotational excitation calculations are presented for both cloud and intercloud conditions which show, in agreement with Jura, that the presently observed optically thin H 2 absorption components are more likely to originate in cold clouds than in the intercloud medium

  4. Medium for Children’s Creativity

    DEFF Research Database (Denmark)

    Borum, Nanna; Kristensen, Kasper; Petersson, Eva

    2014-01-01

    This paper reports on an exploratory study that investigates 16 elementary school children’s interaction with two different mediums for creativity, LEGO® bricks and paper collages, drawing on the previous creativity assessment test carried out by Amabile [1]. The study is based in a playful...... on labor when working with LEGO bricks. It was also evident that the children assigned preconceived affordances to the two mediums. The results from this study should feed into to a technology enhanced playful learning environment and these are the initial steps in the design process....

  5. Heavy quark energy loss in nuclear medium

    International Nuclear Information System (INIS)

    Zhang, Benr-Wei; Wang, Enke; Wang, Xin-Nian

    2003-01-01

    Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark

  6. Power converters for medium voltage networks

    CERN Document Server

    Islam, Md Rabiul; Zhu, Jianguo

    2014-01-01

    This book examines a number of topics, mainly in connection with advances in semiconductor devices and magnetic materials and developments in medium and large-scale renewable power plant technologies, grid integration techniques and new converter topologies, including advanced digital control systems for medium-voltage networks. The book's individual chapters provide an extensive compilation of fundamental theories and in-depth information on current research and development trends, while also exploring new approaches to overcoming some critical limitations of conventional grid integration te

  7. Structure and evolution of the interstellar medium

    International Nuclear Information System (INIS)

    Chieze, J.P.

    1985-10-01

    We give a two dimensional hydrodynamical analysis of HI clouds collisions in order to determine the mass spectrum of diffuse interstellar clouds. We have taken into account evaporation and abrasion by supernovae blast waves. The conditions for cloud merging or fragmentation are precised. Applications to the model of the interstellar medium of Mc Kee and Ostriker are also discussed. On the other hand, we show that molecular clouds belong to a one parameter family which can be identified to the sequence of the gravitationally unstable states of clouds bounded by the uniform pressure of the coronal phase of the interstellar medium. Hierarchical fragmentation of molecular clouds is analysed in this context [fr

  8. Preliminary evaluation of anhydrous ethanol as a solvent in the oilseed extraction of Jatropha curcas L.; Evaluacion preliminar del etanol anhidro como solvente en la extraccion de aceite de semillas de jatrofa (Jatropha curcas L.)

    Energy Technology Data Exchange (ETDEWEB)

    Brossard-Gonzalez, C.; Ferrari, R. A.; Pighinelli, A. L.; Park, K. J.

    2010-07-01

    A preliminary evaluation was performed on anhydrous ethanol as a solvent for the extraction of oil from whole Jatropha curcas L. seeds (32.24 % lipids, 16.05 % proteins), supplied from Mato Grosso, Brazil. The methodology of factorial 2k designs was followed, which included a comparison between pressing and n-hexane extraction methods. The regression model corresponding to the comparison between ethanol and n-hexane, varying extraction time, did not have lack of fit and presented an R2 of 99%. The experimental design for the pressing method, varying press rotation speed and temperature, yielded a poorly fitted linear model. The oil composition extracted with ethanol was similar to those obtained by n-hexane and by pressing. The highest yield (36.7%) was obtained using ethanol for 4 hours. The excess of extracted material was attributed to additional solubilization of impurities that could be diminished by limiting the extraction time to 1 hour. The oil extracted with ethanol and by pressing have the same color. It is presumed that the purification steps for both oils should be similar. Further studies using mixtures of ethanol with small proportions of n-hexane are suggested. (Author) 20 refs.

  9. Development of a method for the determination of caffeine anhydrate in various designed intact tablets [correction of tables] by near-infrared spectroscopy: a comparison between reflectance and transmittance technique.

    Science.gov (United States)

    Ito, Masatomo; Suzuki, Tatsuya; Yada, Shuichi; Kusai, Akira; Nakagami, Hiroaki; Yonemochi, Etsuo; Terada, Katsuhide

    2008-08-05

    Using near-infrared (NIR) spectroscopy, an assay method which is not affected by such elements of tablet design as thickness, shape, embossing and scored line was developed. Tablets containing caffeine anhydrate were prepared by direct compression at various compression force levels using different shaped punches. NIR spectra were obtained from these intact tablets using the reflectance and transmittance techniques. A reference assay was performed by high-performance liquid chromatography (HPLC). Calibration models were generated by the partial least-squares (PLS) regression. Changes in the tablet thickness, shape, embossing and scored line caused NIR spectral changes in different ways, depending on the technique used. As a result, noticeable errors in drug content prediction occurred using calibration models generated according to the conventional method. On the other hand, when the various tablet design elements which caused the NIR spectral changes were included in the model, the prediction of the drug content in the tablets was scarcely affected by those elements when using either of the techniques. A comparison of these techniques resulted in higher predictability under the tablet design variations using the transmittance technique with preferable linearity and accuracy. This is probably attributed to the transmittance spectra which sensitively reflect the differences in tablet thickness or shape as a result of obtaining information inside the tablets.

  10. Topologically identical, but geometrically isomeric layers in hydrous α-, β-Rb[UO2(AsO3OH)(AsO2(OH)2)]·H2O and anhydrous Rb[UO2(AsO3OH)(AsO2(OH)2)

    Science.gov (United States)

    Yu, Na; Klepov, Vladislav V.; Villa, Eric M.; Bosbach, Dirk; Suleimanov, Evgeny V.; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.; Alekseev, Evgeny V.

    2014-07-01

    The hydrothermal reaction of uranyl nitrate with rubidium nitrate and arsenic (III) oxide results in the formation of polymorphic α- and β-Rb[UO2(AsO3OH)(AsO2(OH)2)]·H2O (α-, β-RbUAs) and the anhydrous phase Rb[UO2(AsO3OH)(AsO2(OH)2)] (RbUAs). These phases were structurally, chemically and spectroscopically characterized. The structures of all three compounds are based upon topologically identical, but geometrically isomeric layers. The layers are linked with each other by means of the Rb cations and hydrogen bonding. Dehydration experiments demonstrate that water deintercalation from hydrous α- and β-RbUAs yields anhydrous RbUAs via topotactic reactions.

  11. Optimizing culture medium for debittering constitutive enzyme ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-08-02

    Aug 2, 2010 ... naringinase on different matrices has been studied by many researchers (Busto et ... 10 g/L in the base medium compared to naringin control. Nitrogen ... Fermentation experiments were carried out in shaking flask for 5 days at 28°C with initial pH 6.0. † Values ..... fujikuroi mycelium in fluidized bioreactors.

  12. Jet multiplicity distributions: medium dependence in MLLA

    Energy Technology Data Exchange (ETDEWEB)

    Armesto, Nestor; Pajares, Carlos; Quiroga-Arias, Paloma [Universidade de Santiago de Compostela, Departamento de Fisica de Particulas and IGFAE, Santiago de Compostela (Spain)

    2009-07-15

    We study the medium dependence of the multiplicity distributions in the modified leading logarithmic approximation. We focus in the enhancement in the number of branchings as the partons travel trough a dense medium created in a heavy-ion collision. We study the effect of a higher number of splittings in some jet observables by introducing the medium as a constant (f{sub med}) in the splitting functions. Having as our ansatz for the quark and gluon jets mean multiplicities left angle n{sub G} right angle =e{sup {gamma}}{sup y} and left angle n{sub Q} right angle =r{sup -1}e{sup {gamma}}{sup y}, we study in an analytic approach the dependence with the medium (f{sub med}) of the anomalous dimension ({gamma}), the multiplicity ratio (r), and so the mean multiplicities. We also obtain the higher-order moments of the multiplicity distribution, what allows us to study its dispersion. (orig.)

  13. Wave propagation in thermoelastic saturated porous medium

    Indian Academy of Sciences (India)

    the existence and propagation of four waves in the medium. Three of the waves are ... predicted infinite speed for propagation of ther- mal signals. Lord and ..... saturated reservoir rock (North-sea Sandstone) is chosen for the numerical model ...

  14. Innovation in Small and Medium Firms.

    Science.gov (United States)

    Organisation for Economic Cooperation and Development, Paris (France). Committee for Scientific and Technical Personnel.

    A study analyzed the policies of 20 Organisation for Economic Cooperation and Development (OECD) member countries pertaining to small and medium enterprises (SMEs). Aims of the study were to assess the current role of SMEs as generators and users of innovations, to analyze the components of a favorable climate for innovation in SMEs, and to…

  15. The MIRI Medium Resolution Spectrometer calibration pipeline

    NARCIS (Netherlands)

    Labiano, A.; Azzollini, R.; Bailey, J.; Beard, S.; Dicken, D.; García-Marín, M.; Geers, V.; Glasse, A.; Glauser, A.; Gordon, K.; Justtanont, K.; Klaassen, P.; Lahuis, F.; Law, D.; Morrison, J.; Müller, M.; Rieke, G.; Vandenbussche, B.; Wright, G.

    2016-01-01

    The Mid-Infrared Instrument (MIRI) Medium Resolution Spectrometer (MRS) is the only mid-IR Integral Field Spectrometer on board James Webb Space Telescope. The complexity of the MRS requires a very specialized pipeline, with some specific steps not present in other pipelines of JWST instruments,

  16. Separation medium containing thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Herrera-Alonso, Margarita (Inventor)

    2012-01-01

    A separation medium, such as a chromatography filling or packing, containing a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g, wherein the thermally exfoliated graphite oxide has a surface that has been at least partially functionalized.

  17. Radiculography with water-soluble contraste medium

    International Nuclear Information System (INIS)

    Araujo Pinheiro, R.S. de

    1987-01-01

    The etiologic diagnosis of the lumbar pain is discussed. The radiculography with water-soluble contrast medium is used and 250 cases are studied. Some practical criteria of indication executation and interpretation of the examination are reported. (M.A.C.) [pt

  18. The Digital Medium Meets the Advertising Message.

    Science.gov (United States)

    Nisenholtz, Martin

    1994-01-01

    Discusses the likelihood that companies will use online services as an advertising medium. Topics addressed include the art of interactive marketing; advertising in the digital age; early experiments with interactive marketing, including the use of videotex and videodisc; and recent trends that set the stage for interactive marketing to personal…

  19. Influence of small and medium building engineering ...

    African Journals Online (AJOL)

    This study investigated the influence of small and medium building engineering entrepreneurship for the actualization of vision 20:2020 in Kebbi State, Nigeria. The study was conducted in Birnin Kebbi, Zuru and Argungu Local Government Areas of Kebbi State. The data were obtained from both primary and secondary ...

  20. Sound Art. Klang als Medium der Kunst

    DEFF Research Database (Denmark)

    Forskningsformidling på udstilling om lydkunst på ZKM i Karlsruhe. Lavet i samarbejde med Mats Lindström, leder af elektronmusikstudiet EMS (Stockholm). Udstillingen er en del af Morten Søndergaards (AAU) præsentation af skandinavisk lydkunst under titlen 'Unheard Avantgarde', der igen er en del ...... den store udstilling 'Sound as a Medium of Art'....

  1. Medium corrections to nucleon-nucleon interactions

    International Nuclear Information System (INIS)

    Dortmans, P.J.; Amos, K.

    1990-01-01

    The Bethe-Goldstone equations have been solved for both negative and positive energies to specify two nucleon G-matrices fully off of the energy shell. Medium correction effects of Pauli blocking and of the auxiliary potential are included in infinite matter systems characterized by fermi momenta in the range 0.5 fm -1 to 1.8 fm -1 . The Paris interaction is used as the starting potential in most calculations. Medium corrections are shown to be very significant over a large range of energies and densities. On the energy shell values of G-matrices vary markedly from those of free two nucleon (NN) t-matrices which have been solved by way of the Lippmann-Schwinger equation. Off of the energy shell, however, the free and medium corrected Kowalski-Noyes f-ratios rate are quite similar suggesting that a useful model of medium corrected G-matrices are appropriately scaled free NN t-matrices. The choice of auxiliary potential form is also shown to play a decisive role in the negative energy regime, especially when the saturation of nuclear matter is considered. 30 refs., 7 tabs., 7 figs

  2. Fluidized bed dry dense medium coal beneficiation

    CSIR Research Space (South Africa)

    North, Brian C

    2017-10-01

    Full Text Available medium beneficiation using a fluidized bed was investigated. Bed materials of sand, magnetite and ilmenite were used in a laboratory sized cylindrical fluidized bed. The materials were individually tested, as were mixes of sand and heavy minerals. Coal...

  3. Phase object retrieval through scattering medium

    Science.gov (United States)

    Zhao, Ming; Zhao, Meijing; Wu, Houde; Xu, Wenhai

    2018-05-01

    Optical imaging through a scattering medium has been an interesting and important research topic, especially in the field of biomedical imaging. However, it is still a challenging task due to strong scattering. This paper proposes to recover the phase object behind the scattering medium from one single-shot speckle intensity image using calibrated transmission matrices (TMs). We construct the forward model as a non-linear mapping, since the intensity image loses the phase information, and then a generalized phase retrieval algorithm is employed to recover the hidden object. Moreover, we show that a phase object can be reconstructed with a small portion of the speckle image captured by the camera. The simulation is performed to demonstrate our scheme and test its performance. Finally, a real experiment is set up, we measure the TMs from the scattering medium, and then use it to reconstruct the hidden object. We show that a phase object of size 32 × 32 is retrieved from 150 × 150 speckle grains, which is only 1/50 of the speckles area. We believe our proposed method can benefit the community of imaging through the scattering medium.

  4. Intergalactic medium heating by dark matter

    NARCIS (Netherlands)

    Ripamonti, E.; Mapelli, M.; Ferrara, A.

    2006-01-01

    Abstract: We derive the evolution of the energy deposition in the intergalactic medium (IGM) by dark matter (DM) decays/annihilations for both sterile neutrinos and light dark matter (LDM) particles. At z > 200 sterile neutrinos transfer a fraction f_abs~0.5 of their rest mass energy into the IGM;

  5. Nuclear matter as a nonlinear optical medium

    International Nuclear Information System (INIS)

    Hefter, E.F.; Papini, G.

    1986-01-01

    This paper is concerned with the question whether nuclear matter should be considered as a nonlinear optical medium. Taking, in a pragmatic way, quality and quantity of the results of well-established linear and nonlinear approaches as the main criterion, an affirmative answer is seen to be consistent with long-standing practices adhered to in nuclear physics

  6. Small and Medium Enterprises and Biopharmaceutical Innovations ...

    African Journals Online (AJOL)

    Small and Medium Enterprises and Biopharmaceutical Innovations in Africa: ... through biotechnological processes with links to biological sources especially those of live ... There are more than 500 biopharmaceutical products that have been ... By Country · List All Titles · Free To Read Titles This Journal is Open Access.

  7. Medium optimization for endochitinase production by recombinant ...

    African Journals Online (AJOL)

    The optimal concentrations of three factors were investigated by the response surface methodology using Box- Behnken design. The optimal medium components obtained for achieving the maximum activity of the endochitinase were as follows: Yeast extract 24.36 g/l, tryptone 20 g/l, YNB 5.0 g/l, potassium phosphate 100 ...

  8. Oyster mycelium on the liquid medium

    Directory of Open Access Journals (Sweden)

    Mariusz Gapiński

    2013-12-01

    Full Text Available The research presents the results of oyster mycelium growth on the liquid medium. The growth of 4-mycelium genius: Pleurotus citrinopileatus Singer, Pleurotus djamor Fries, Boedjin, Pleurotus erynii Fr. Kumm. and Pleurotus precoce Fr. Quel was tested. The quality and quantity of mycelium was assumed.

  9. Borromean structures in medium-heavy nuclei

    DEFF Research Database (Denmark)

    Hove, Dennis; Fedorov, Dmitri Vladimir; Fynbo, Hans Otto Uldall

    2014-01-01

    Borromean nuclear cluster structures are expected at the corresponding driplines. We locate the regions in the nuclear chart with the most promising constituents, it being protons and alpha-particles and investigate in details the properties of the possible borromean two-alpha systems in medium h...... 134Te−α−α structure in its ground state and low-lying spectrum....

  10. Medium Modifications of Hadrons in Photon Induced Reactions

    International Nuclear Information System (INIS)

    Schadmand, S.

    2004-01-01

    Indications for in-medium modifications of hadron properties are reported from photoabsorption and meson production experiments. Strong medium modifications are observed in inclusive photoabsorption experiments and theoretical models investigate the in-medium dynamics of baryon resonances and their coupling to mesons. Recent experiments study the in-medium behavior of scalar and vector mesons where theoretical models expect in-medium modifications of the meson spectral functions that might be connected to partial restoration of chiral symmetry

  11. Medium dependence of multiplicity distributions in MLLA

    Energy Technology Data Exchange (ETDEWEB)

    Armesto, Nestor; Pajares, Carlos; Quiroga-Arias, Paloma [Universidade de Santiago de Compostela, Departamento de Fisica de Particulas and IGFAE, Santiago de Compostela (Spain)

    2009-06-15

    We study the modification of the multiplicity distributions in MLLA due to the presence of a QCD medium. The medium is introduced through a multiplicative constant (f{sub med}) in the soft infrared parts of the kernels of the QCD evolution equations. Using the asymptotic ansatz for mean multiplicities of the quark and gluons, left angle n{sub G} right angle =e{sup {gamma}}{sup y} and left angle n{sub Q} right angle =r {sup -1}e{sup {gamma}}{sup y}, respectively, we study two cases: fixed {gamma} as previously considered in the literature, and fixed {alpha}{sub s}. We find opposite behaviors of the dispersion of the multiplicity distributions with increasing f{sub med} in both cases. For fixed {gamma} the dispersion decreases, while for fixed {alpha}{sub s} it increases. (orig.)

  12. Medium dependence of multiplicity distributions in MLLA

    International Nuclear Information System (INIS)

    Armesto, Nestor; Pajares, Carlos; Quiroga-Arias, Paloma

    2009-01-01

    We study the modification of the multiplicity distributions in MLLA due to the presence of a QCD medium. The medium is introduced through a multiplicative constant (f med ) in the soft infrared parts of the kernels of the QCD evolution equations. Using the asymptotic ansatz for mean multiplicities of the quark and gluons, left angle n G right angle =e γy and left angle n Q right angle =r -1 e γy , respectively, we study two cases: fixed γ as previously considered in the literature, and fixed α s . We find opposite behaviors of the dispersion of the multiplicity distributions with increasing f med in both cases. For fixed γ the dispersion decreases, while for fixed α s it increases. (orig.)

  13. Teaching in English-medium programmes

    DEFF Research Database (Denmark)

    Lauridsen, Karen M.; Cozart, Stacey Marie

    in such a way that they take into account their students’ diverse cultural and linguistic backgrounds and use them as a strength in the classroom; and they should be able to engage all students in joint learning activities so that both the Danish and the international students benefit from the programme......This contribution describes and discusses the module Teaching in English-medium programmes, an elective module offered as part of the teacher training programme for assistant professors (“adjunktpædagogikum”) at Aarhus University. In order to complete the whole programme, assistant professors must...... have at least one such elective module (http://upnet.au.dk/adjunktkursus/). Aarhus University offers the teacher training programme in Danish and in English for international faculty. Teaching in English-medium programmes is part of the Danish track, but taught through English. Building...

  14. Physics of the interstellar and intergalactic medium

    CERN Document Server

    Draine, Bruce T

    2010-01-01

    This is a comprehensive and richly illustrated textbook on the astrophysics of the interstellar and intergalactic medium--the gas and dust, as well as the electromagnetic radiation, cosmic rays, and magnetic and gravitational fields, present between the stars in a galaxy and also between galaxies themselves. Topics include radiative processes across the electromagnetic spectrum; radiative transfer; ionization; heating and cooling; astrochemistry; interstellar dust; fluid dynamics, including ionization fronts and shock waves; cosmic rays; distribution and evolution of the interstellar medium; and star formation. While it is assumed that the reader has a background in undergraduate-level physics, including some prior exposure to atomic and molecular physics, statistical mechanics, and electromagnetism, the first six chapters of the book include a review of the basic physics that is used in later chapters. This graduate-level textbook includes references for further reading, and serves as an invaluable resourc...

  15. El Naschie's coherence on the subquantum medium

    International Nuclear Information System (INIS)

    Agop, M.; Ioannou, P.D.; Nica, P.; Galusca, G.; Stefan, M.

    2005-01-01

    In the hydrodynamic formulation of the Scale Relativity theory one shows that a stable vortices distribution of bipolaron type induces superconducting pairs by means of the quantum potential. One builds the superconducting fractal by an iterated map and demonstrates that the superconducting pairs results as projections of this fractal. Thus, usual mechanisms (as example the exchange interaction used in the bipolaron theory) are reduced to the coherence on the subquantum medium in a ε (∞) space (El Naschie's coherence)

  16. Business Model Innovation for Small Medium Enterprises

    OpenAIRE

    Wirania Swasty

    2015-01-01

    Indonesian economy through Small Medium Enterprises (SMEs) is expected to absorb labor and contribute to the growth of Gross Domestic Product. However, SMEs lack both managerial and technical skills. This research is about business model innovation for SMEs especially in fashion and garment industry. Study used qualitative approach by mentoring four selected SMEs in Babakan Penghulu Village– Cinambo Sub-District, Eastern Bandung. The tools used to analyze them including PEST analysis, Porter’...

  17. Medium-energy ion reflection from solids

    CERN Document Server

    Mashkova, ES

    1985-01-01

    ``Medium-Energy Ion Reflection from Solids'' analyses the results of experimental, theoretical and computer investigations on the process of scattering of ions by solid surfaces. Surface scattering is a relatively young and rapidly developing branch of the physics of atomic collisions and the literature on this subject has rapidly grown.As the first monograph devoted specifically to surface scattering of ions, this book is directed at scientists involved in ion-solid interaction studies.

  18. On accretion from an inhomogeneous medium

    International Nuclear Information System (INIS)

    Davies, R.E.; Pringle, J.E.

    1980-01-01

    Hypersonic accretion flow in two dimensions from an infinite medium which contains a small density and/or velocity gradient is considered. To first order in rsub(a)/h, where rsub(a) is the accretion radius and h the scale of the gradient, the accretion rate is unaffected and the accreted angular momentum is zero. Thus previous estimates of the amount of angular momentum accreted may severely overestimate the actual value. (author)

  19. Small and medium power reactors 1985

    International Nuclear Information System (INIS)

    1986-05-01

    This report is intended for designers and planners concerned with Small and Medium Power Reactors. It provides a record of the presentations during the meetings held on this subject at the Agency's General Conference in September 1985. This information should be useful as it indicates the principal findings and main conclusions and recommendations resulting from these meetings. A separate abstract was prepared for each of the 10 presentations in this report

  20. Radiculography with reduced amounts of contrast medium

    International Nuclear Information System (INIS)

    Signorini, E.; Caputo, N.; Chiurulla, C.; Ciorba, E.; Pelliccioli, G.P.; Cianciulli, E.

    1984-01-01

    Because of the frequency and seriousness of side effects observed after radiculography, due to, among the other things, the amount of contrast medium, the authors describe a method that gives diagnostically satisfactory results using a low dose of contrast and a tangent-beam technique. Among 106 patients undergoing radiculography with a tangent-beam technique and Iopamidol, only 4 developed mild side effects, namely headache in three cases and headache with nausea in one. (Author)

  1. Leeuwpan fine coal dense medium plant

    CSIR Research Space (South Africa)

    Lundt, M

    2010-11-01

    Full Text Available Beneficiation 2010, 4–6 May 2010. 671The Journal of The Southern African Institute of Mining and Metallurgy VOLUME 110 NOVEMBER 2010 L Leeuwpan fine coal dense medium plant mixed with magnetite in the launder and enters... with production. Plant equipment operational changes Cyclone spigot changes In an attempt to lower the cut-point density, the spigot on the L 672 NOVEMBER 2010 VOLUME 110 The Journal of The Southern African Institute of Mining and Metallurgy Figure 1...

  2. Wave modulation in a nonlinear dispersive medium

    International Nuclear Information System (INIS)

    Kim, Y.C.; Khadra, L.; Powers, E.J.

    1980-01-01

    A model describing the simultaneous amplitude and phase modulation of a carrier wave propagating in a nonlinear dispersive medium is developed in terms of nonlinear wave-wave interactions between the sidebands and a low frequency wave. It is also shown that the asymmetric distribution of sidebands is determined by the wavenumber dependence of the coupling coefficient. Digital complex demodulation techniques are used to study modulated waves in a weakly ionized plasma and the experimental results support the analytical model

  3. Medium energy probes and nuclear structure

    International Nuclear Information System (INIS)

    Ginocchio, J.N.

    1984-01-01

    In this paper we explore two topics. The first topic is the marriage of medium energy reaction theory with the interacting boson model of nuclei in such a way that the multiple scattering is summed to all orders. The second topic is an exactly solvable potential model which gives realistic shell model eigenfunctions which can be used to calculate static and transition nuclear densities. (orig./HSI)

  4. Dynamical Model about Rumor Spreading with Medium

    Directory of Open Access Journals (Sweden)

    Xiaxia Zhao

    2013-01-01

    Full Text Available Rumor is a kind of social remark, that is untrue, and not be confirmed, and spreads on a large scale in a short time. Usually, it can induce a cloud of pressure, anxiety, and panic. Traditionally, it is propagated by word of mouth. Nowadays, with the emergence of the internet, rumors can be spread by instant messengers, emails, or publishing. With this new pattern of spreading, an ISRW dynamical model considering the medium as a subclass is established. Beside the dynamical analysis of the model, we mainly explore the mechanism of spreading of individuals-to-individuals and medium-to-individual. By numerical simulation, we find that if we want to control the rumor spreading, it will not only need to control the rate of change of the spreader subclass, but also need to control the change of the information about rumor in medium which has larger influence. Moreover, to control the effusion of rumor is more important than deleting existing information about rumor. On the one hand, government should enhance the management of internet. On the other hand, relevant legal institutions for punishing the rumor creator and spreader on internet who can be tracked should be established. Using this way, involved authorities can propose efficient measures to control the rumor spreading to keep the stabilization of society and development of economy.

  5. Medium temperature carbon dioxide gas turbine reactor

    International Nuclear Information System (INIS)

    Kato, Yasuyoshi; Nitawaki, Takeshi; Muto, Yasushi

    2004-01-01

    A carbon dioxide (CO 2 ) gas turbine reactor with a partial pre-cooling cycle attains comparable cycle efficiencies of 45.8% at medium temperature of 650 deg. C and pressure of 7 MPa with a typical helium (He) gas turbine reactor of GT-MHR (47.7%) at high temperature of 850 deg. C. This higher efficiency is ascribed to: reduced compression work around the critical point of CO 2 ; and consideration of variation in CO 2 specific heat at constant pressure, C p , with pressure and temperature into cycle configuration. Lowering temperature to 650 deg. C provides flexibility in choosing materials and eases maintenance through the lower diffusion leak rate of fission products from coated particle fuel by about two orders of magnitude. At medium temperature of 650 deg. C, less expensive corrosion resistant materials such as type 316 stainless steel are applicable and their performance in CO 2 have been proven during extensive operation in AGRs. In the previous study, the CO 2 cycle gas turbomachinery weight was estimated to be about one-fifth compared with He cycles. The proposed medium temperature CO 2 gas turbine reactor is expected to be an alternative solution to current high-temperature He gas turbine reactors

  6. Does culture medium influence offspring birth weight?

    Science.gov (United States)

    Carrasco, Beatriz; Boada, Montserrat; Rodríguez, Ignacio; Coroleu, Buenaventura; Barri, Pedro N; Veiga, Anna

    2013-11-01

    To determine whether the type of medium used to culture human embryos in vitro influences neonatal birth weight after IVF/intracytoplasmic sperm injection (ICSI). A prospective study and a retrospective study. Private assisted reproduction center. The prospective study included 449 IVF/ICSI cycles from August to December 2008. The retrospective analysis was performed for 2,518 IVF/ICSI cycles from October 2006 to December 2010. In the prospective study, patients were randomized for embryo culture in Cook or Vitrolife medium. The retrospective study was performed with three different culture media (MediCult, Cook, and Vitrolife). Mean birth weight, adjusted for gestational age and gender (z score) of newborns. In the prospective study, the average z score was -0.19 ± 0.85 in Cook and 0.08 ± 1.40 in Vitrolife. In the retrospective study, the z scores obtained in each group were as follows: Cook, -0.14 ± 0.96; MediCult, 0.06 ± 1.13; and Vitrolife, 0.03 ± 1.05. No significant differences were observed regarding the birth weight of children born in the different groups in both studies. The results do not show any relationship between the medium used for in vitro culture and mean birth weight adjusted for gestational age and gender of singletons born after IVF/ICSI. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  7. Medium-Term Oil Market Report 2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    How much oil will the world consume in 2011? What role will OPEC play in global oil production? Will biofuels become an important part of the oil market? The International Energy Agencys (IEA) Medium-Term Oil Market Report tackles these questions, adopting a perspective that goes beyond the traditional short-term market analysis provided in the IEAs monthly Oil Market Report. Drawing on current futures curves and the investment threshold for upstream projects, the Medium-Term Oil Market Report analyses how global demand and supply balances may develop in the next five years. The forecasts look in detail at product demand and the supply potential from all the firmly planned individual upstream and downstream projects around the world. The results provide invaluable insights on vital issues such as surplus production capacity and product supply. The rapid pace of change in the oil market means that forecasts can become outdated very quickly. This interim update provides the opportunity to rebase the data and forecasts in the annual Medium-Term Oil Market Report and to discuss and analyse new issues affecting the oil industry. Policymakers, market analysts, energy experts and anyone interested in understanding and following trends in the oil market should find this report extremely useful.

  8. Medium-Term Oil Market Report 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    How much oil will the world consume in 2012? What role will OPEC play in global oil production? Will biofuels become an important part of the oil market? How will the refinery sector cope? The International Energy Agency (IEA) Medium-Term Oil Market Report tackles these questions, adopting a perspective that goes beyond the traditional short-term market analysis provided in the IEA Oil Market Report. Drawing on current futures curves and the investment threshold for upstream projects, the Medium-Term Oil Market Report analyses how global demand and supply balances may develop. By assessing all firmly planned upstream and downstream projects worldwide, this report forecasts supply and demand potential for crude and petroleum products over the next five years. The results provide an invaluable insight into vital issues such as surplus production capacity and product supply. An essential report for all policymakers, market analysts, energy experts and anyone interested in understanding and following oil market trends, the Medium-Term Oil Market Report is a further element of the strong commitment of the IEA to improving and expanding the quality, timeliness and accuracy of energy data and analysis.

  9. Anisotropically biaxial strain in non-polar (112-0) plane In x Ga1-x N/GaN layers investigated by X-ray reciprocal space mapping.

    Science.gov (United States)

    Zhao, Guijuan; Li, Huijie; Wang, Lianshan; Meng, Yulin; Ji, Zesheng; Li, Fangzheng; Wei, Hongyuan; Yang, Shaoyan; Wang, Zhanguo

    2017-07-03

    In this study, the indium composition x as well as the anisotropically biaxial strain in non-polar a-plane In x Ga 1-x N on GaN is studied by X-ray diffraction (XRD) analysis. In accordance with XRD reciprocal lattice space mapping, with increasing indium composition, the maximum of the In x Ga 1-x N reciprocal lattice points progressively shifts from a fully compressive strained to a fully relaxed position, then to reversed tensile strained. To fully understand the strain in the ternary alloy layers, it is helpful to grow high-quality device structures using a-plane nitrides. As the layer thickness increases, the strain of In x Ga 1-x N layer releases through surface roughening and the 3D growth-mode.

  10. Tracer transfer in consolidated porous medium and fractured porous medium: experimentations and modelling

    International Nuclear Information System (INIS)

    Dalla Costa, C.

    2007-07-01

    We try to identify and model physical and chemical mechanisms governing the water flow and the solute transport in fractured consolidated porous medium. An original experimental device was built. The 'cube' consists of an idealized fractured medium reproduced by piling up consolidated porous cubes of 5 cm edge. Meanwhile, columns of the homogeneous consolidated porous medium are studied. The same anionic tracing technique is used in both cases. Using a system analysis approach, we inject concentration pulses in the device to obtain breakthrough curves. After identifying the mass balance and the residence time, we fit the CD and the MIM models to the experimental data. The MIM model is able to reproduce experimental curves of the homogeneous consolidated porous medium better than the CD model. The mobile water fraction is in accordance with the porous medium geometry. The study of the flow rate influence highlights an interference dispersion regime. It was not possible to highlight the observation length influence in this case. On the contrary, we highlight the effect of the observation scale on the fractured and porous medium, comparing the results obtained on a small 'cube' and a big 'cube'. The CD model is not satisfactory in this case. Even if the MIM model can fit the experimental breakthrough curves, it was not possible to obtain unique parameters for the set of experiments. (author)

  11. A combined interfacial and in-situ polymerization strategy to construct well-defined core-shell epoxy-containing SiO2-based microcapsules with high encapsulation loading, super thermal stability and nonpolar solvent tolerance

    Directory of Open Access Journals (Sweden)

    Yin Jia

    2016-10-01

    Full Text Available SiO2-based microcapsules containing hydrophobic molecules exhibited potential applications such as extrinsic self-healing, drug delivery, due to outstanding thermal and chemical stability of SiO2. However, to construct SiO2-based microcapsules with both high encapsulation loading and long-term structural stability is still a troublesome issue, limiting their further utilization. We herein design a single-batch route, a combined interfacial and in-situ polymerization strategy, to fabricate epoxy-containing SiO2-based microcapsules with both high encapsulation loading and long-term structural stability. The final SiO2-based microcapsules preserve high encapsulation loading of 85.7 wt% by controlling exclusively hydrolysis and condensed polymerization at oil/water interface in the initial interfacial polymerization step. In the subsequent in-situ polymerization step, the initial SiO2-based microcapsules as seeds could efficiently harvest SiO2 precursors and primary SiO2 particles to finely tune the SiO2 wall thickness, thereby enhancing long-term structural stability of the final SiO2-based microcapsules including high thermal stability with almost no any weight loss until 250°C, and strong tolerance against nonpolar solvents such as CCl4 with almost unchanged core-shell structure and unchanged core weight after immersing into strong solvents for up to 5 days. These SiO2-based microcapsules are extremely suited for processing them into anticorrosive coating in the presence of nonpolar solvents for self-healing application.

  12. Characterization of metal and trace element contents of particulate matter (PM10) emitted by vehicles running on Brazilian fuels-hydrated ethanol and gasoline with 22% of anhydrous ethanol.

    Science.gov (United States)

    Ferreira da Silva, Moacir; Vicente de Assunção, João; de Fátima Andrade, Maria; Pesquero, Célia R

    2010-01-01

    Emission of fine particles by mobile sources has been a matter of great concern due to its potential risk both to human health and the environment. Although there is no evidence that one sole component may be responsible for the adverse health outcomes, it is postulated that the metal particle content is one of the most important factors, mainly in relation to oxidative stress. Data concerning the amount and type of metal particles emitted by automotive vehicles using Brazilian fuels are limited. The aim of this study was to identify inhalable particles (PM(10)) and their trace metal content in two light-duty vehicles where one was fueled with ethanol while the other was fueled with gasoline mixed with 22% of anhydrous ethanol (gasohol); these engines were tested on a chassis dynamometer. The elementary composition of the samples was evaluated by the particle-induced x-ray emission technique. The experiment showed that total emission factors ranged from 2.5 to 11.8 mg/km in the gasohol vehicle, and from 1.2 to 3 mg/km in the ethanol vehicle. The majority of particles emitted were in the fine fraction (PM(2.5)), in which Al, Si, Ca, and Fe corresponded to 80% of the total weight. PM(10) emissions from the ethanol vehicle were about threefold lower than those of gasohol. The elevated amount of fine particulate matter is an aggravating factor, considering that these particles, and consequently associated metals, readily penetrate deeply into the respiratory tract, producing damage to lungs and other tissues.

  13. A medium energy neutron deep penetration experiment

    International Nuclear Information System (INIS)

    Amian, W.; Cloth, P.; Druecke, V.; Filges, D.; Paul, N.; Schaal, H.

    1986-11-01

    A deep penetration experiment conducted at the Los Alamos WNR facility's Spallation Neutron Target is compared with calculations using intra-nuclear-cascade and S N -transport codes installed at KFA-IRE. In the experiment medium energy reactions induced by neutrons between 15 MeV and about 150 MeV inside a quasi infinite slab of iron have been measured using copper foil monitors. Details of the experimental procedure and the theoretical methods are described. A comparison of absolute reaction rates for both experimentally and theoretically derived reactions is given. The present knowledge of the corresponding monitor reaction cross sections is discussed. (orig.)

  14. In medium modification of nucleon electromagnetic properties

    International Nuclear Information System (INIS)

    Khanna, F.; Rakhimov, A.; Yakhsiev, U.

    1997-01-01

    Since nucleons are composite objects, their internal structure is expected to be changed by nuclear environment. A Skyrme like Lagrangian is proposed to consider such effects, namely the modification of electromagnetic (EM) properties of the nucleon. The static properties and EM form factors were obtained. It was shown that the charge radius of the nucleon increased in medium and the mass and axial coupling constant are reduced. The enhancement of magnetic moment of proton is smaller than that obtained in non-topological soliton model.Obtained results may be useful in electron nucleus scattering analysis.(A.A.D.)

  15. The Casimir effect: medium and geometry

    International Nuclear Information System (INIS)

    Marachevsky, Valery N

    2012-01-01

    Theory of the Casimir effect is presented in several examples. Casimir–Polder-type formulas, Lifshitz theory and theory of the Casimir effect for two gratings separated by a vacuum slit are derived. Equations for the electromagnetic field in the presence of a medium and dispersion are discussed. The Casimir effect for systems with a layer of 2 + 1 fermions is studied. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker's 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’. (paper)

  16. Relativistic energy loss in a dispersive medium

    DEFF Research Database (Denmark)

    Houlrik, Jens Madsen

    2002-01-01

    The electron energy loss in a dispersive medium is obtained using macroscopic electrodynamics taking advantage of a static frame of reference. Relativistic corrections are described in terms of a dispersive Lorentz factor obtained by replacing the vacuum velocity c by the characteristic phase...... velocity c/n, where n is the complex index of refraction. The angle-resolved energy-loss spectrum of a Drude conductor is analyzed in detail and it is shown that the low-energy peak due to Ohmic losses is enhanced compared to the classical approximation....

  17. Interactions between intergalactic medium and galaxies

    International Nuclear Information System (INIS)

    Einasto, J.; Saar, E.

    1977-01-01

    The interaction of galaxies with the environmental gas both in clusters and in small groups of galaxies is investigated. Interaction between galaxies and the ambient medium can be considered simply as final touches in the process of galaxy formation. Large relative velocities of galaxies in their clusters and of the intercluster gas result in a loss of the intergalactic gas, that in its turn affects the morphology of cluster galaxies. Interaction between the coronal clouds and the gas in the disk of spiral galaxies may result in regular patterns of star formation and in the bending of planes of galaxies

  18. Adiabatic supernova expansion into the circumstellar medium

    International Nuclear Information System (INIS)

    Band, D.L.; Liang, E.P.

    1987-01-01

    We perform one dimensional numerical simulations with a Lagrangian hydrodynamics code of the adiabatic expansion of a supernova into the surrounding medium. The early expansion follows Chevalier's analytic self-similar solution until the reverse shock reaches the ejecta core. We follow the expansion as it evolves towards the adiabatic blast wave phase. Some memory of the earlier phases of expansion is retained in the interior even when the outer regions expand as a blast wave. We find the results are sensitive to the initial configuration of the ejecta and to the placement of gridpoints. 6 refs., 2 figs

  19. Medium energy hadron scattering from nuclei

    International Nuclear Information System (INIS)

    Ginocchio, J.N.; Wenes, G.

    1986-01-01

    The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a γ unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from 154 Sm and 154 Gd. 27 refs., 5 figs., 1 tab

  20. Polycyclic aromatic hydrocarbons in stellar medium

    Science.gov (United States)

    Rastogi, Shantanu

    2005-06-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important com- ponent of the Interstellar Medium (ISM). They are being used as probes for understanding of process and conditions of different astrophysical environments. The understanding of their IR spectra and its variations with PAH size and ionization state is useful in characterizing the ISM. Spectral features of model graphene sheets and also that of smaller PAH molecules are reported. The variation of intensity with charge state of the molecule shows that cations give a better correlation with observations. The relationship between changes in charge distribution with intensity changes upon ionization has been probed.

  1. Electromagnetically Induced Transparency In Rydberg Atomic Medium

    Science.gov (United States)

    Deng, Li; Cong, Lu; Chen, Ai-Xi

    2018-03-01

    Due to possessing big principal quantum number, Rydberg atom has some unique properties, for example: its radiative lifetime is long, dipole moment is large, and interaction between atoms is strong and so on. These properties make one pay attention to Rydberg atoms. In this paper we investigate the effects of Rydberg dipole-dipole interactions on electromagnetically induced transparency (EIT) schemes and group velocity in three-level systems of ladder type, which provides theoretical foundation for exploring the linear and nonlinear characteristics of light in a Rydberg electromagnetically-induced-transparency medium.

  2. Medium modifications of nucleon electromagnetic form factors

    Energy Technology Data Exchange (ETDEWEB)

    Horikawa, T. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Bentz, W. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan)]. E-mail: bentz@keyaki.cc.u-tokai.ac.jp

    2005-11-28

    We use the Nambu-Jona-Lasinio model as an effective quark theory to investigate the medium modifications of the nucleon electromagnetic form factors. By using the equation of state of nuclear matter derived in this model, we discuss the results based on the naive quark-scalar diquark picture, the effects of finite diquark size, and the meson cloud around the constituent quarks. We apply this description to the longitudinal response function for quasielastic electron scattering. RPA correlations, based on the nucleon-nucleon interaction derived in the same model, are also taken into account in the calculation of the response function.

  3. Electromagnetic properties of neutrinos in a medium

    International Nuclear Information System (INIS)

    Nieves, J.F.; Pal, P.B.

    1989-01-01

    We show that, contrary to the situation in the vacuum, a Majorana neutrino can have electric and magnetic dipole moments in a medium. This is because of new contributions, equal for a particle and its antiparticle, that can arise only in a material background. For Dirac neutrinos, these contributions make the magnitudes of the dipole moments of the particle and the antiparticle unequal. We discuss the conditions which give rise to such effects, with particular attention to the role played by the discrete symmetries C, P, and T

  4. Nuclear medium effects on the nucleon properties

    International Nuclear Information System (INIS)

    Gerard, A.

    1986-06-01

    The idea that the nuclear medium may modify the properties of the nucleon is not really a new one. But until these last few years the intrinsic properties of the nucleon such as its mass, baryonic or electromagnetic size, magnetic moments, were hardly suspected to be substantially modified by the nuclear environment. The question raised essentially from two categories of experimental investigations, in quite different kinematical regimes and it remains at the present time a controversal subject. In this paper I try to review the present status of experimental investigations and some of the recent theoretical developments relevant to this topic

  5. Cooperative networking in a heterogeneous wireless medium

    CERN Document Server

    Ismail, Muhammad

    2013-01-01

    This brief focuses on radio resource allocation in a heterogeneous wireless medium. It presents radio resource allocation algorithms with decentralized implementation, which support both single-network and multi-homing services. The brief provides a set of cooperative networking algorithms, which rely on the concepts of short-term call traffic load prediction, network cooperation, convex optimization, and decomposition theory. In the proposed solutions, mobile terminals play an active role in the resource allocation operation, instead of their traditional role as passive service recipients in the networking environment.

  6. Distributed medium access control in wireless networks

    CERN Document Server

    Wang, Ping

    2013-01-01

    This brief investigates distributed medium access control (MAC) with QoS provisioning for both single- and multi-hop wireless networks including wireless local area networks (WLANs), wireless ad hoc networks, and wireless mesh networks. For WLANs, an efficient MAC scheme and a call admission control algorithm are presented to provide guaranteed QoS for voice traffic and, at the same time, increase the voice capacity significantly compared with the current WLAN standard. In addition, a novel token-based scheduling scheme is proposed to provide great flexibility and facility to the network servi

  7. Superluminous laser pulse in an active medium

    International Nuclear Information System (INIS)

    Fisher, D.L.; Tajima, T.

    1993-12-01

    Physical conditions are obtained to make the propagation velocity of a laser pulse and thus the phase velocity of the excited wake be at any desired value, including that equal to or greater than the speed of light. The provision of an active-plasma laser medium with an appropriately shaped pulse allows not only replenishment of laser energy loss to the wakefield but also acceleration of the group velocity of photons. A stationary solitary solution in the accelerated frame is obtained from the model equations and simulations thereof for the laser, plasma and atoms. This approach has applications in photonics and telecommunications as well as wakefield accelerators

  8. The interstellar medium in galaxies - An overview

    Science.gov (United States)

    Knapp, G. R.

    1990-01-01

    Recent observational developments on the subject of the interstellar medium in galaxies are summarized, with emphasis placed on global properties. The properties and distribution of the ISM in the solar neighborhood and in the Galactic plane are examined and a number of results from the most important observational probes (HI, CO, and infrared) are described. A recent development is the observation of the ISM in galaxies of all morphological types, early to late. These developments are summarized and the properties of different types of galaxies are compared to one another. The origin of radio galaxies, the effect of environment, and the prospects for direct observations of ISM evolution in galaxies are discussed.

  9. Managing Safety in Small and Medium Enterprises

    DEFF Research Database (Denmark)

    Stephen, legg; Olsen, Kirsten Bendix; Ian S., laird

    2015-01-01

    on safety in SMEs, showing how most current policy and legislation on occupational health and safety (OSH) and the work environment is based on large enterprises and that there is a relative paucity of research on OSH in SMEs. In a summary of current knowledge, it is argued that modern OHS legislation......This paper presents a conceptual model for increasing acceptable working environments for SMEs. It also acts as an editorial for the special issue of Safety Science on ‘Managing safety in small and medium enterprises (SMEs)’. It describes how seven of the ten papers in the special issue originate...

  10. Laser light scattering in Brownian medium

    International Nuclear Information System (INIS)

    Suwono; Santoso, Budi; Baiquni, A.

    1983-01-01

    The principle of laser light scattering in Brownian medium and photon correlation spectroscopy are described in detail. Their application to the study of the behaviour of a polystyrene latex solution are discussed. The auto-correlation function of light scattered by the polystyrene latex solution in various angle, various temperature and in various sample times, have been measured. Information on the translation diffusion coefficient and size on the particle can be obtained from the auto-correlation function. Good agreement between the available data and experiment is shown. (author)

  11. The question of caution in professional medium

    International Nuclear Information System (INIS)

    Godard, O.

    2006-01-01

    Contrived in Europe to tackle the environment protection policies and management of natural resources, the principle of caution has seen since 1990 its interest developed towards the fields of food safety and public health. The importance and the relevance of questions have lead the national institute of research and safety to constitute a working group to explore the problems and the potentialities that could be linked to the explicit introduction of this principle and this in the field of the prevention of professional risks. This work tackles several aspects of the question of caution in professional medium such history, concepts, evolution...as well as cases judged exemplary ones. (N.C.)

  12. Degradation testing of Mg alloys in Dulbecco's modified eagle medium: Influence of medium sterilization.

    Science.gov (United States)

    Marco, Iñigo; Feyerabend, Frank; Willumeit-Römer, Regine; Van der Biest, Omer

    2016-05-01

    This work studies the in vitro degradation of Mg alloys for bioabsorbable implant applications under near physiological conditions. For this purpose, the degradation behaviour of Mg alloys in Dulbecco's modified eagle medium (DMEM) which is a commonly used cell culture medium is analysed. Unfortunately, DMEM can be contaminated by microorganisms, acidifying the medium and accelerating the Mg degradation process by dissolution of protective degradation layers, such as (Mgx,Cay)(PO4)z. In this paper the influence of sterilization by applying UV-C radiation and antibiotics (penicillin/streptomycin) is analysed with two implant material candidates: Mg-Gd and Mg-Ag alloys; and pure magnesium as well as Mg-4Y-3RE as a reference. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Characterisation of Ferrosilicon Dense Medium Separation Material

    International Nuclear Information System (INIS)

    Waanders, F. B.; Mans, A.

    2003-01-01

    Ferrosilicon is used in the dense medium separation of iron ore at Kumba resources, Sishen, South Africa. Due to high cost and losses that occur during use, maximum recovery by means of magnetic separation is aimed for. The purpose of this project was to determine the characteristics of the unused Fe-Si and then to characterise the changes that occur during storage and use thereof. Scanning electron microscopy was used to determine the composition of each sample, whilst Moessbauer spectroscopy yielded a two-sextet spectrum with hyperfine magnetic field strengths of 20 and 31 T, respectively, for the fresh samples. Additional hematite oxide peaks appeared in the Moessbauer spectra after use of the Fe-Si over a length of time, but this did not result in a dramatic degradation of the medium. No definite changes occurred during correct storage methods. It was, however, found that the biggest loss of Fe-Si was due to the abrasion of the particles, which resulted in the formation of an oxihydroxide froth, during the process.

  14. Perspective on small and medium size reactors

    International Nuclear Information System (INIS)

    Stahlkopf, K.E.; Braun, C.

    1985-01-01

    There has been renewed interests in the United States in small and medium size nuclear power plants (600 MWe or less). The reasons for this include: (1) there is a large uncertainty in load growth projections. Small to medium size nuclear power plants may be better suited to meet uncertain load growth projections. (2) It has been argued that a large economy of scale exists because of the nature of nuclear power installations. A recent examination of the French program shows that no economy of scale exists between the 900 MWe and 1300 MWe plants. Others have suggested that it is possible to reduce the economy of scale so it is not a prohibitive factor. (3) In the past in the United States, it has been customary for several smaller utilities to share the output of a large nuclear plant to take advantage of the perceived economy of scale. Difficulties have been encountered by some of these enterprises. (4) An examination of capacity factors for the United States shows that plants of smaller output appear to operate more reliably and economically than larger plants

  15. GABA interaction with lipids in organic medium

    International Nuclear Information System (INIS)

    Beltramo, D.; Kivatinitz, S.; Lassaga, E.; Arce, A.

    1987-01-01

    The interaction of 3 H-GABA and 14 C-glutamate with lipids in an aqueous organic partition system was studied. With this partition system 3 H-GABA and 14 C-glutamate were able to interact with sphingomyelin, sulfatide, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine and phosphatidic acid but not with cholesterol or ceramide. In an homogeneous aqueous medium the authors could not demonstrate any interaction between 3 H-GABA-lipids. The apparent dissociation constants (K/sub d/) for 3 H-GABA-lipids or 14 C-glutamate-lipids interactions inorganic medium were in the millimolar range and maximal charge between 3 and 7 moles of GABA or glutamate by mole of lipid. Amino acids such as glutamic acid, β-alanine and glycine displaced 3 H-GABA with the same potency as GABA itself; thus these results show that the interaction lacks pharmacological specificity. To detect this interaction lipid concentrations higher than 2 μM were required and in the partition system 3 H-GABA and lipid phosphorus were both concentrated at the interface. Therefore, lipids tested with a biphasic partition system do not fulfill the classical criteria for a neurotransmitter receptor at least not for GABA and glutamate. 15 references, 1 figure, 3 tables

  16. Sector boundary distortion in the interplanetary medium

    International Nuclear Information System (INIS)

    Suess, S.T.; Feynman, J.

    1977-01-01

    We address the theoretical problem of the effect of a solar wind meridional velocity gradient on the orientation, or tipping, of a line embedded within the interplanetary plasma. We find that rotations of from 30degree to 75degree, between 1.5 solar radii and I AU, are produced when observed values for the solar wind velocity and its meridional gradient are used. This is not a small effect, nor is it difficult to calculate: it is a natural consequence of any meridional velocity gradient in the interplanetary medium. In relating this result to observed sector boundaries we note that the latitude dependence of the width of interplanetary magnetic sectors (dominant polarity or Rosenberg-Coleman effect) implies that sector boundaries at I AU are generally inclined at an angle of from 10degree to 20degree to the solar equatorial plane. Conversely, studies of photospheric magnetic fields have led to the conclusion that sector boundaries near the sun are, on the average, at large angles (approx.90degree) to the solar equatorial plane. If the dominant polarity effect were to be produced by rotation in the interplanetary medium, the sign of the solar wind meridional velocity gradient must not change at the equator, but the gradient does have to change sign for +/- boundary crossings in comparison to -/+ boundary crossings

  17. Medium-size power plants. Economic options

    International Nuclear Information System (INIS)

    Vogelweith, L.; Baujat, J.; Goutail, J.

    1978-01-01

    In this paper the authors describe a method for economic evaluation of a nuclear power plant project such as advocated by the IAEA but modified through the introduction of various parameters that may affect the evaluation, i.e. the weighted evaluation rate, the annual increase in the cost of fuel, and the discount rate. The method is applied to barge-based medium-size reactors (125 MW(e)). The authors calculate the investment cost, together with the costs of administration, operation and maintenance; use is made of current assumptions regarding the price of fuel for the case of a reference nuclear plant and an oil-fired plant of the same power and in the same programme. In this way the authors derive the discounted cost of the nuclear programme and concurrent conventional programme on the basis of the following assumptions: a weighted inflation rate varying between 0 and 6% per year; an annual increase in real fuel prices ranging from 0 to 3%; and a real discount rate, equal to the real interest rate, varying between 4 and 7% per year and corresponding to nominal discount rates of up to 13.4%. The conclusion reached is that, given the real interest rates actually prevailing on the financial market, a weighted inflation rate foreseen by the majority of experts, and a rise in real fuel prices of the order of 1% per year, the medium-size nuclear power plant is more economical than a conventional plant of the same output. (author)

  18. INNOVATIVE CULTURE IN SMALL AND MEDIUM ENTERPRISES

    Directory of Open Access Journals (Sweden)

    Aluisio Broering Mambrini

    2011-10-01

    Full Text Available In the last two decades, innovation has been a key driver of economic growth. Innovation is closely related to creating value and generating wealth through successful service to consumer needs. Thus, it is not necessarily restricted to the use of new knowledge generated from research, but on the development of new products or services that are obtained with creative use of knowledge, new or already known. This study aimed to identify management practices that promote a culture of innovation in small and medium enterprises and analyze how they contribute to the innovative capacity of these companies. The research method was the multiple case study with six small and medium businesses that have at least one case of significant innovation in its history. The main results showed that amongst the practices are: a performance in highly specialized niches and deep focus on customer needs; b strong investment and incorporation of new knowledge outside the company (open innovation; c speed and agility in the absorption and deployment of new knowledge and technologies; d retention of employees; e acting as an integrator combining diverse knowledge and technologies; f the information management of the knowledge acquired by the company; g little concern to patent the technology; h flexibility and informal, fluid and open communication between employees of the company that promotes agility in management and i the management of partnerships across the value chain, including the functional areas.

  19. Shock propagation in a heterogeneous medium

    International Nuclear Information System (INIS)

    Elbaz, D.

    2011-01-01

    In the frame of the inertial confinement fusion in direct drive, the use of foams as ablator allows the reduction of hydrodynamic instabilities created on the target by the direct laser irradiation. The foam is made up of carbon (CH) fibers impregnated of cryogenic deuterium-tritium (DT). In the past, studies have been carried out considering this foam to be a homogeneous medium. Yet, the foam presents heterogeneous features. We study the effects of this heterogeneity on the shock velocity when the laser irradiates the target. Thanks to experimental and numerical studies, we show that the shock propagates faster in the heterogeneous medium than in the homogeneous one with the same averaged density. This velocity gap depends on the presence rate of the CH fibers in the foam, the density ratio, the adiabatic coefficient and the foam geometry. We model the foam by different ways, more and more complex. The shock velocity modification is due to the baroclinicity which, during the interaction between the shock front and the interface, creates a vorticity deposition, responsible for the shock acceleration. Accordingly, an interface, which is plane and perpendicular to the front shock, maximizes the vorticity deposition and increases the velocity gaps between heterogeneous and homogeneous media. We found a correlation between the kinetic energy behind the shock front and the velocities relative difference. We compared our results with two analytical models. However, the system is not closed, so we can't for the moment develop a predictive model. (author) [fr

  20. A direct sampling method for inverse electromagnetic medium scattering

    KAUST Repository

    Ito, Kazufumi; Jin, Bangti; Zou, Jun

    2013-01-01

    In this paper, we study the inverse electromagnetic medium scattering problem of estimating the support and shape of medium scatterers from scattered electric/magnetic near-field data. We shall develop a novel direct sampling method based

  1. Casimir force in the presence of a medium

    International Nuclear Information System (INIS)

    Kheirandish, Fardin; Soltani, Morteza; Sarabadani, Jalal

    2010-01-01

    We investigate the Casimir effect in the presence of a medium by quantizing the electromagnetic field in the presence of a magnetodielectric medium using the path-integral technique. For a given medium with definite electric and magnetic susceptibilities, explicit expressions for the Casimir force are obtained. The Lifshitz formula is recovered and in the absence of a medium the results tend to the original Casimir force between two conducting parallel plates immersed in the quantum electromagnetic vacuum.

  2. 21 CFR 573.180 - Anhydrous ammonia.

    Science.gov (United States)

    2010-04-01

    ... to corn plant material and thoroughly blended prior to ensiling. It is used or intended for use as a source of nonprotein nitrogen in cattle feed in accordance with paragraphs (a)(1), (2), or (3) as follows... premix is a source of nonprotein nitrogen and minerals. (ii) In addition to the requirements of paragraph...

  3. 7 CFR 58.325 - Anhydrous milkfat.

    Science.gov (United States)

    2010-01-01

    ... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw... directly from milk or cream. The cream used shall be comparable to the flavor quality specified above for U.... The cream or oil shall be pasteurized in accordance with the procedures for cream for buttermaking...

  4. An element with an anhydrous liquid electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Toda, K; Isiguro, Y; Ota, K; Sinoda, K; Yamamoto, K

    1983-01-01

    A light element metal of the lithium or sodium type is used in the element, along with a cathode of Mo02 or CuF2 and an anyhdrous liquid electrolyte from an oganic solvent with an ionogenic additive. An adsorbent which has a composition corresponding to the formula Mx/n((A102)x(Si02)y) with zH20, where M is the ion of sodium, potassium or calcium; n is the valency M and x, y and z are the coefficients which show the content of A102, Si02 and H20, respectively, is introduced into the cathode, separator or electrolyte. The element has high storage life.

  5. Chemical Safety Alert: Anhydrous Ammonia Theft

    Science.gov (United States)

    This extremely hazardous substance is largely used as an agricultural fertilizer, but is also a key ingredient in the illegal production of methamphetamines. It is stored as a liquid under pressure, but becomes a toxic gas when released.

  6. Medium optimization for protopectinase production by batch culture of

    African Journals Online (AJOL)

    Medium optimization for protopectinase production by batch culture of. C Fan, Z Liu, L Yao. Abstract. Optimization of medium compositions for protopectinase production by Aspergillus terreus in submerged culture was carried out. The medium components having significant effect on protopectinase production were reported ...

  7. On the effects from the simultaneous occurrence of the critical Casimir and dispersion forces between conical colloid particle and a thick plate immersed in nonpolar critical fluid

    Directory of Open Access Journals (Sweden)

    Valchev Galin

    2018-01-01

    Full Text Available Here we study the interplay between the van der Waals (vdWF and critical Casimir forces (CCF, as well as the total force (TF between a conical colloid particle and a thick planar slab. We do that using general scaling arguments and mean-field type calculations utilizing the so-called “surface integration approach”, a generalization of the well known Derjaguin approximation. Its usage in the present research, requires knowledge on the forces between two parallel slabs, confining in between some fluctuating fluid medium characterized by its temperature T and chemical potential μ. The surfaces of the colloid particle and the slab are assumed coated by thin layers exerting strong preference to the liquid phase of a simple fluid, or one of the components of a binary mixture, modeled by strong adsorbing local surface potentials, ensuring the so-called (+,+ boundary conditions. On the other hand, the core region of the slab and the particle, influence the fluid by long-ranged competing dispersion potentials. We demonstrate that for a suitable set of colloid-fluid, slab-fluid, and fluid-fluid coupling parameters the competition between the effects due to the coatings and the core regions of the objects, result, when one changes T or μ, in sign change of the Casimir force (CF and the TF acting between the colloid and the slab. Such an effect can provide a strategy for solving problems with handling, feeding, trapping and fixing of microparts in nanotechnology.

  8. Transitioning from Maori-Medium to English-Medium Education: Emerging Findings of a Pilot Study

    Science.gov (United States)

    Hill, Richard

    2016-01-01

    Maori-bilingual education in New Zealand has come a long way towards injecting life into the Maori language. However, only a small number of families commit to bilingual education for the long term. This paper discusses why Maori parents either turn away from Maori-bilingual education or prematurely transition to English-medium schools. It then…

  9. Ultrasound fields in an attenuating medium

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Gandhi,, D; O'Brien,, W.D., Jr.

    1993-01-01

    of the rectangles and sums all contributions to arrive at the spatial impulse response for the aperture and field point. This approach makes it possible to model all transducer apertures, and the program can readily calculate the emitted, pulse-echo and continuous wave field. Attenuation is included by splitting...... it into a frequency dependent part and frequency independent part. The latter results in an attenuation factor that is multiplied onto the responses from the individual elements, and the frequency dependent part is handled by attenuating the basic one-dimensional pulse. The influence on ultrasound fields from......Ultrasound fields propagating in tissue will undergo changes in shape not only due to diffraction, but also due to the frequency dependent attenuation. Linear fields can be fairly well predicted for a non-attenuating medium like water by using the Tupholme-Stepanishen method for calculating...

  10. Study of QCD medium by sum rules

    Energy Technology Data Exchange (ETDEWEB)

    Mallik, S [Saha Institute of Nuclear Physics, Calcutta (India)

    1998-08-01

    Though it has no analogue in condensed matter physics, the thermal QCD sum rules can, nevertheless, answer questions of condensed matter type about the QCD medium. The ingredients needed to write such sum rules, viz. the operator product expansion and the spectral representation at finite temperature, are reviewed in detail. The sum rules are then actually written for the case of correlation function of two vector currents. Collecting information on the thermal average of the higher dimension operators from other sources, we evaluate these sum rules for the temperature dependent {rho}-meson parameters. Possibility of extracting more information from the combined set of all sum rules from different correlation functions is also discussed. (author) 30 refs., 2 figs.

  11. Medium Duty Electric Vehicle Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, Robin J. D. [Smith Electric Vehicles Corporation, Kansas City, MO (United States)

    2015-05-31

    The Smith Electric Vehicle Demonstration Project (SDP) was integral to the Smith business plan to establish a manufacturing base in the United States (US) and produce a portfolio of All Electric Vehicles (AEV’s) for the medium duty commercial truck market. Smith focused on the commercial depot based logistics market, as it represented the market that was most ready for the early adoption of AEV technology. The SDP enabled Smith to accelerate its introduction of vehicles and increase the size of its US supply chain to support early market adoption of AEV’s that were cost competitive, fully met the needs of a diverse set of end users and were compliant with Federal safety and emissions requirements. The SDP accelerated the development and production of various electric drive vehicle systems to substantially reduce petroleum consumption, reduce vehicular emissions of greenhouse gases (GHG), and increase US jobs.

  12. Abundances in the diffuse interstellar medium

    International Nuclear Information System (INIS)

    Harris, A.W.

    1988-04-01

    The wealth of interstellar absorption line data obtained with the Copernicus and IUE satellites has opened up a new era in studies of the interstellar gas. It is now well established that certain elements, generally those with high condensation temperatures, are substantially under-abundant in the gas-phase relative to total solar or cosmic abundances. This depletion of elements is due to the existence of solid material in the form of dust grains in the interstellar medium. Surprisingly, however, recent surveys indicate that even volatile elements such as Zn and S are significantly depleted in many sight lines. Developments in this field which have been made possible by the large base of UV interstellar absorption line data built up over recent years are reviewed and the implications of the results for our understanding of the physical processes governing depletion are discussed. (author)

  13. Polarization of submillimetre lines from interstellar medium

    Science.gov (United States)

    Zhang, Heshou; Yan, Huirong

    2018-04-01

    Magnetic fields play important roles in many astrophysical processes. However, there is no universal diagnostic for the magnetic fields in the interstellar medium (ISM) and each magnetic tracer has its limitation. Any new detection method is thus valuable. Theoretical studies have shown that submillimetre fine-structure lines are polarized due to atomic alignment by ultraviolet photon-excitation, which opens up a new avenue to probe interstellar magnetic fields. We will, for the first time, perform synthetic observations on the simulated three-dimensional ISM to demonstrate the measurability of the polarization of submillimetre atomic lines. The maximum polarization for different absorption and emission lines expected from various sources, including star-forming regions are provided. Our results demonstrate that the polarization of submillimetre atomic lines is a powerful magnetic tracer and add great value to the observational studies of the submilimetre astronomy.

  14. Cosmic rays and the interstellar medium

    International Nuclear Information System (INIS)

    Wolfendale, A.W.

    1986-01-01

    It is inevitable that there is a close connection between cosmic rays and the ISM insofar as the propagation of cosmic rays is conditioned by the magnetic field in the ISM and the cosmic rays interact with the gas (and photon fluxes) in this medium. This paper deals with both topics. Propagation effects manifest themselves as an anisotropy in arrival directions and a review is given of anisotropy measurements and their interpretation. The status of studies of cosmic ray interactions is examined whit particular reference to the information about the ISM itself which comes from observations of the flux of secondary γ-rays produced by cosmic ray interactions with gas, the situation regarding molecular as in the Inner Galaxy being of particular concern

  15. Development of novel Alicyclobacillus spp. isolation medium.

    Science.gov (United States)

    Chang, S; Kang, D-H

    2005-01-01

    To develop a new isolation medium with higher recovery rates of Alicyclobacillus spp. SK agar was developed with optimized incubation temperature, pH, acidulant, Tween 80 concentration and divalent cation addition. Results indicate that detection of Alicyclobacillus spp. by SK agar was significantly higher (P > 0.05) than those obtained by K agar, orange serum agar, and potato dextrose agar. Current media used for Alicyclobacillus spp. isolation still resulted in high numbers of false negative products. The sensitivity of SK agar to Alicyclobacillus spp. allows detection of low numbers of Alicyclobacillus spp. and also provides a more higher isolation results compared with currently used media. SK agar will be useful to the fruit juice industry to obtain more accurate numbers of contaminant Alicyclobacillus spp. With this media, false negative samples can be reduced, and the likelihood of exported products being rejected can be greatly reduced.

  16. Nonlinear dynamo in the intracluster medium

    Science.gov (United States)

    Beresnyak, Andrey; Miniati, Francesco

    2018-05-01

    Hot plasma in galaxy clusters, the intracluster medium is observed to be magnetized with magnetic fields of around a μG and the correlation scales of tens of kiloparsecs, the largest scales of the magnetic field so far observed in the Universe. Can this magnetic field be used as a test of the primordial magnetic field in the early Universe? In this paper, we argue that if the cluster field was created by the nonlinear dynamo, the process would be insensitive to the value of the initial field. Our model combines state of the art hydrodynamic simulations of galaxy cluster formation in a fully cosmological context with nonlinear dynamo theory. Initial field is not a parameter in this model, yet it predicts magnetic scale and strength compatible with observations.

  17. Light Vector Mesons in the Nuclear Medium

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Michael; Nasseripour, Rakhsha; Weygand, Dennis; Djalali, Chaden; Tur, Clarisse; Mosel, Ulrich; Muehlich, Pascal; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Ambrozewicz, Pawel; Anghinolfi, Marco; Asryan, Gegham; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, James; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Carnahan, Bryan; Casey, Liam; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dharmawardane, Kahanawita; Dickson, Richard; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Feldman, Gerald; Feuerbach, Robert; Fradi, Ahmed; Funsten, Herbert; Garcon, Michel; Gavalian, Gagik; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gordon, Christopher; Gothe, Ralf; Griffioen, Keith; Guidal, Michel; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hakobyan, Rafael; Hanretty, Charles; Hardie, John; Hassall, Neil; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Kellie, James; Khandaker, Mahbubul; Khetarpal, Puneet; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Krahn, Zebulun; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Lachniet, Jeff; Laget, Jean; Langheinrich, Jorn; Lawrence, David; Li, Ji; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Prok, Yelena; Protopopescu, Dan; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Ronchetti, Federico; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Smith, Elton; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinsky, Aleksey; Stepanyan, Stepan; Stepanyan, Samuel; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Williams, Michael; Wolin, Elliott; Yegneswaran, Amrit; Zana, Lorenzo; Zhang, Bin; Zhang, Jixie; Zhao, Bo; Zhao, Zhiwen

    2008-07-01

    The light vector mesons ($\\rho$, $\\omega$, and $\\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\\rho$ meson mass spectrum was extracted after the $\\omega$ and $\\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body eff

  18. Casimir stress in an inhomogeneous medium

    International Nuclear Information System (INIS)

    Philbin, T.G.; Xiong, C.; Leonhardt, U.

    2010-01-01

    The Casimir effect in an inhomogeneous dielectric is investigated using Lifshitz's theory of electromagnetic vacuum energy. A permittivity function that depends continuously on one Cartesian coordinate is chosen, bounded on each side by homogeneous dielectrics. The result for the Casimir stress is infinite everywhere inside the inhomogeneous region, a divergence that does not occur for piece-wise homogeneous dielectrics with planar boundaries. A Casimir force per unit volume can be extracted from the infinite stress but it diverges on the boundaries between the inhomogeneous medium and the homogeneous dielectrics. An alternative regularization of the vacuum stress is considered that removes the contribution of the inhomogeneity over small distances, where macroscopic electromagnetism is invalid. The alternative regularization yields a finite Casimir stress inside the inhomogeneous region, but the stress and force per unit volume diverge on the boundaries with the homogeneous dielectrics. The case of inhomogeneous dielectrics with planar boundaries thus falls outside the current understanding of the Casimir effect.

  19. A medium resolution fingerprint matching system

    Directory of Open Access Journals (Sweden)

    Ayman Mohammad Bahaa-Eldin

    2013-09-01

    Full Text Available In this paper, a novel minutiae based fingerprint matching system is proposed. The system is suitable for medium resolution fingerprint images obtained by low cost commercial sensors. The paper presents a new thinning algorithm, a new features extraction and representation, and a novel feature distance matching algorithm. The proposed system is rotation and translation invariant and is suitable for complete or partial fingerprint matching. The proposed algorithms are optimized to be executed on low resource environments both in CPU power and memory space. The system was evaluated using a standard fingerprint dataset and good performance and accuracy were achieved under certain image quality requirements. In addition, the proposed system was compared favorably to that of the state of the art systems.

  20. CAS medium-size nuclear plants

    International Nuclear Information System (INIS)

    Vogelweith, L.; Weiss, A.

    1977-01-01

    CEA has developed a range of pressurized water reactors of the type CAS Compact, which are adapted to civil ship propulsion, or to electric power production, combined possibly with heat production, up to outputs equivalent to 125MW(e). Nuclear plants equipped with these reactors are suitable for medium-size electric networks, especially in developing countries, because they are easily adaptable, owing to their flexibility; they can be installed and used in a variety of ways (on land, floating installation, combination of electric power and other production, etc.); they can be used as training reactors by countries wishing to limit their investment plans before undertaking a wider nuclear development. Examples of two possible realizations are presented: as a floating plant, and as a combined electric and desalting plant. (author)