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Sample records for nh3 tsp voc

  1. Structural and electrical characterization of tamarind seed polysaccharide (TSP) doped with NH4HCO2

    Science.gov (United States)

    Premalatha, M.; Mathavan, T.; Selvasekarapandian, S.; Selvalakshmi, S.

    2018-04-01

    In the modern era, development of electrochemical energy devices such as batteries, fuel cells and supercapacitors gain attention due to the deficiency of renewable energy resources. More specifically, proton conducting materials create prime interest in the development of electrochemical devices. In this regards, a novel proton conducting biopolymer electrolyte based on Tamarind Seed Polysaccharide (TSP) was synthesized with different concentration of ammonium formate (NH4HCO2). The amorphous nature of the polymer electrolytes has been identified by XRD technique. The observed ionic conductivity values reveal that the biopolymer containing 1 g TSP: 0.4 g NH4HCO2 has highest ionic conductivity 1.23×10-3 S cm-1.

  2. Photoelectric characteristics of CH3NH3PbI3/p-Si heterojunction

    Science.gov (United States)

    Yamei, Wu; Ruixia, Yang; Hanmin, Tian; Shuai, Chen

    2016-05-01

    Organic-inorganic hybrid perovskite CH3NH3PbI3 film is prepared on p-type silicon substrate using the one-step solution method to form a CH3NH3PbI3/p-Si heterojunction. The film morphology and structure are characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The photoelectric properties of the CH3NH3PbI3/p-Si heterojunction are studied by testing the current-voltage (I-V) with and without illumination and capacitance-voltage (C-V) characteristics. It turns out from the I-V curve without illumination that the CH3NH3PbI3/p-Si heterojunction has a rectifier feature with the rectification ratio over 70 at the bias of ±5 V. Also, there appears a photoelectric conversion phenomenon on this heterojunction with a short circuit current (Isc) of 0.16 μA and an open circuit voltage (Voc) of about 10 mV The high frequency C-V characteristic of the Ag/CH3NH3PbI3/p-Si heterojunction turns out to be similar to that of the metal-insulator-semiconductor (MIS) structure, and a parallel translation of the C-V curve along the forward voltage axis is found. This parallel translation means the existence of defects at the CH3NH3PbI3/p-Si interface and positive fixed charges in the CH3NH3PbI3 layer. The defects at the interface of the CH3NH3PbI3/p-Si heterojunction result in the dramatic decline of the Voc. Besides, the C-V test of CH3NH3PbI3 film shows a non-linear dielectric property and the dielectric value is about 4.64 as calculated. Project supported by the Hebei Province Natural Science Foundation of China (No. F2014202184) and the Tianjin Natural Science Foundation of China (No. 15JCZDJC37800).

  3. Low Temperature Catalyst for NH3 Removal

    Science.gov (United States)

    Monje, Oscar; Melendez, Orlando

    2013-01-01

    Air revitalization technologies maintain a safe atmosphere inside spacecraft by the removal of C02, ammonia (NH3), and trace contaminants. NH3 onboard the International Space Station (ISS) is produced by crew metabolism, payloads, or during an accidental release of thermal control refrigerant. Currently, the ISS relies on removing NH3 via humidity condensate and the crew wears hooded respirators during emergencies. A different approach to cabin NH3 removal is to use selective catalytic oxidation (SCO), which builds on thermal catalytic oxidation concepts that could be incorporated into the existing TCCS process equipment architecture on ISS. A low temperature platinum-based catalyst (LTP-Catalyst) developed at KSC was used for converting NH3 to H20 and N2 gas by SCO. The challenge of implementing SCO is to reduce formation of undesirable byproducts like NOx (N20 and NO). Gas mixture analysis was conducted using FTIR spectrometry in the Regenerable VOC Control System (RVCS) Testbed. The RVCS was modified by adding a 66 L semi-sealed chamber, and a custom NH3 generator. The effect of temperature on NH3 removal using the LTP-Catalyst was examined. A suitable temperature was found where NH3 removal did not produce toxic NO, (NO, N02) and N20 formation was reduced.

  4. Cytotoxicity of TSP in 3D Agarose Gel Cultured Cell.

    Directory of Open Access Journals (Sweden)

    Song-I Chun

    Full Text Available A reference reagent, 3-(trimethylsilyl propionic-2, 2, 3, 3-d4 acid sodium (TSP, has been used frequently in nuclear magnetic resonance (NMR and magnetic resonance spectroscopy (MRS as an internal reference to identify cell and tissue metabolites, and determine chemical and protein structures. This reference material has been exploited for the quantitative and dynamic analyses of metabolite spectra acquired from cells. The aim of this study was to evaluate the cytotoxicity of TSP on three-dimensionally, agarose gel, cultured cells.A human osteosarcoma cell line (MG-63 was selected, and cells were three dimensionally cultured for two weeks in an agarose gel. The culture system contained a mixture of conventional culture medium and various concentrations (0, 1, 3, 5, 7, 10, 20 30 mM of TSP. A DNA quantification assay was conducted to assess cell proliferation using Quant-iT PicoGreen dsDNA reagent and kit, and cell viability was determined using a LIVE/DEAD Viability/Cytotoxicity kit. Both examinations were performed simultaneously at 1, 3, 7 and 14 days from cell seeding.In this study, the cytotoxicity of TSP in the 3D culture of MG-63 cells was evaluated by quantifying DNA (cell proliferation and cell viability. High concentrations of TSP (from 10 to 30 mM reduced both cell proliferation and viability (to 30% of the control after one week of exposure, but no such effects were found using low concentrations of TSP (0-10 mM.This study shows that low concentrations of TSP in 3D cell culture medium can be used for quantitative NMR or MRS examinations for up to two weeks post exposure.

  5. Projection of SO2, NOx, NMVOC, NH3 and particulate matter

    DEFF Research Database (Denmark)

    Nielsen, Ole-Kenneth; Plejdrup, Marlene Schmidt; Winther, Morten

    2012-01-01

    This report contains a description of models and background data for projection of SO2, NOX, NH3, NMVOC, TSP, PM10 and PM2.5 for Denmark. The emissions are projected to 2030 using basic scenarios together with the expected results of a few individual policy measures. Official Danish forecasts...

  6. Impact of CH3NH3PbI3-PCBM bulk heterojunction active layer on the photovoltaic performance of perovskite solar cells

    Science.gov (United States)

    Chaudhary, Dhirendra K.; Kumar, Pankaj; Kumar, Lokendra

    2017-10-01

    We report here the impact of CH3NH3PbI3-PCBM bulk heterojunction (BHJ) active layer on the photovoltaic performance of perovskite solar cells. The solar cells were prepared in normal architecture on FTO coated glass substrates with compact TiO2 (c-TiO2) layer on FTO as electron transport layer (ETL) and poly(3-hexylthiophene) (P3HT) as hole transport layer (HTL). For comparison, a few solar cells were also prepared in planar heterojunction structure using CH3NH3PbI3 only as the active layer. The bulk heterojunction CH3NH3PbI3-PCBM active layer exhibited very large crystalline grains of 2-3 μm compared to ∼150 nm only in CH3NH3PbI3 active layer. Larger grains in bulk-heterojunction solar cells resulted in enhanced power conversion efficiency (PCE) through enhancement in all the photovoltaic parameters compared to planar heterojunction solar cells. The bulk-heterojunction solar cells exhibited ∼9.25% PCE with short circuit current density (Jsc) of ∼18.649 mA/cm2, open circuit voltage (Voc) of 0.894 V and Fill Factor (FF) of 0.554. There was ∼36.9% enhancement in the PCE of bulk-heterojunction solar cells compared to that of planar heterojunction solar cells. The larger grains are formed as a result of incorporation on PCBM in the active layer.

  7. Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

    Science.gov (United States)

    Yuan, Bin; Coggon, Matthew M.; Koss, Abigail R.; Warneke, Carsten; Eilerman, Scott; Peischl, Jeff; Aikin, Kenneth C.; Ryerson, Thomas B.; de Gouw, Joost A.

    2017-04-01

    Concentrated animal feeding operations (CAFOs) emit a large number of volatile organic compounds (VOCs) to the atmosphere. In this study, we conducted mobile laboratory measurements of VOCs, methane (CH4) and ammonia (NH3) downwind of dairy cattle, beef cattle, sheep and chicken CAFO facilities in northeastern Colorado using a hydronium ion time-of-flight chemical-ionization mass spectrometer (H3O+ ToF-CIMS), which can detect numerous VOCs. Regional measurements of CAFO emissions in northeastern Colorado were also performed using the NOAA WP-3D aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign. Alcohols and carboxylic acids dominate VOC concentrations and the reactivity of the VOCs with hydroxyl (OH) radicals. Sulfur-containing and phenolic species provide the largest contributions to the odor activity values and the nitrate radical (NO3) reactivity of VOC emissions, respectively. VOC compositions determined from mobile laboratory and aircraft measurements generally agree well with each other. The high time-resolution mobile measurements allow for the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the emissions of ethanol are primarily associated with feed storage and handling. Based on mobile laboratory measurements, we apply a multivariate regression analysis using NH3 and ethanol as tracers to determine the relative importance of animal-related emissions (animal exhalation and waste) and feed-related emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls, carboxylic acids and sulfur-containing species. Emissions of phenolic species and nitrogen-containing species are predominantly associated with animals and their waste.

  8. TETRAHEURÍSTICA SISTÉMICA (THS PARA EL TSP SYSTEMIC TETRAHEURISTIC FOR THE TSP

    Directory of Open Access Journals (Sweden)

    Jorge Iván Pérez Rave

    2010-08-01

    Full Text Available Este artículo presenta un novedoso método, basado en elementos del pensamiento sistémico, para solucionar instancias del problema del vendedor viajero (TSP, el cual es comparado en términos de eficacia y eficiencia con "nearest neighbour", "cheapest insertion", "two-wwy exchange improvement" y "branch and bound". El primer apartado introduce la optimización combinatoria, el segundo ofrece un marco de referencia, el tercero presenta la metodología empleada, el cuarto apartado presenta el desarrollo de la tetraheurística sistémica, seguido del análisis de varianza y de rangos de Duncan para los factores: método y cantidad de ciudades; este apartado finaliza con el análisis del comportamiento de la proporción de "fracasos" del algoritmo propuesto a medida que aumenta la complejidad del TSP. Como resultado se obtiene un método para resolver instancias del TSP, conformado por tres heurísticas misionales: 1."vecino más cercano", 2. "sacrificio cortoplacista" y 3. "traslado LIFO", y una de apoyo llamada "búsqueda derecha 4P4". El diseño de la heurística denominada "sacrificio cortoplacista" es inspirado en el análisis sistémico del "vecino más cercano", al cual se le identifica el arquetipo de "soluciones rápidas que fallan", con aplicación a decisiones cotidianas. La tetraheurística sistémica se destaca, respecto a las demás, en solución arrojada y en tiempo computacional consumido, especialmente cuando incrementa la complejidad del TSP.This paper presents a novel method to solve instances of the TSP. This method is comparable in effectiveness and efficiency with "nearest neighbour", "cheapest insertion", "two-way exchange improvement" and "branch and bound". The first section provides a literature review of the combinatorial optimization, the second provides a reference frame, the third the methodology used and the fourth contains, inter alia, system thinking, AxB factorial design and management tool CAP-DO. The fourth

  9. Relativistic GW calculations on CH3NH3PbI3 and CH3NH3SnI3 perovskites for solar cell applications.

    Science.gov (United States)

    Umari, Paolo; Mosconi, Edoardo; De Angelis, Filippo

    2014-03-26

    Hybrid AMX3 perovskites (A = Cs, CH3NH3; M = Sn, Pb; X = halide) have revolutionized the scenario of emerging photovoltaic technologies, with very recent results demonstrating 15% efficient solar cells. The CH3NH3PbI3/MAPb(I(1-x)Cl(x))3 perovskites have dominated the field, while the similar CH3NH3SnI3 has not been exploited for photovoltaic applications. Replacement of Pb by Sn would facilitate the large uptake of perovskite-based photovoltaics. Despite the extremely fast progress, the materials electronic properties which are key to the photovoltaic performance are relatively little understood. Density Functional Theory electronic structure methods have so far delivered an unbalanced description of Pb- and Sn-based perovskites. Here we develop an effective GW method incorporating spin-orbit coupling which allows us to accurately model the electronic, optical and transport properties of CH3NH3SnI3 and CH3NH3PbI3, opening the way to new materials design. The different CH3NH3SnI3 and CH3NH3PbI3 electronic properties are discussed in light of their exploitation for solar cells, and found to be dominantly due to relativistic effects. These effects stabilize the CH3NH3PbI3 material towards oxidation, by inducing a deeper valence band edge. Relativistic effects, however, also increase the material band-gap compared to CH3NH3SnI3, due to the valence band energy downshift (~0.7 eV) being only partly compensated by the conduction band downshift (~0.2 eV).

  10. An entropy-based improved k-top scoring pairs (TSP) method for ...

    African Journals Online (AJOL)

    An entropy-based improved k-top scoring pairs (TSP) (Ik-TSP) method was presented in this study for the classification and prediction of human cancers based on gene-expression data. We compared Ik-TSP classifiers with 5 different machine learning methods and the k-TSP method based on 3 different feature selection ...

  11. 5 CFR 1601.12 - Investing future deposits in the TSP Funds.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Investing future deposits in the TSP... PARTICIPANTS' CHOICES OF TSP FUNDS Investing Future Deposits § 1601.12 Investing future deposits in the TSP.... All participants may elect to invest all or any portion of their deposits in any of the TSP Funds. [70...

  12. Ultrasonic irradiation-promoted one-pot synthesis of CH3NH3PbBr3 quantum dots without using flammable CH3NH2 precursor

    Science.gov (United States)

    Jiang, Han; Wang, Chunlei; Lv, Changgui; Xu, Shuhong; Zhu, Li; Zhang, Ruohu; Cui, Yiping

    2017-02-01

    At present, the CH3NH3PbBr3 quantum dots (QDs) reported in the literature usually contain two synthesis steps: the initial preparation of CH3NH3Br via the reaction of flammable CH3NH2 and HBr, together with the subsequent formation of CH3NH3PbBr3 QDs. To avoid the use of dangerous CH3NH2, this work develops a novel one-pot method for synthesizing CH3NH3PbBr3 QDs using safe and commercially available reactants (CH3NH3Cl, KBr and PbCl2). It is found that ultrasonic treatment plays a key role during the synthesis of CH3NH3PbBr3 QDs. Without ultrasonic irradiation, it is not possible to synthesize CH3NH3PbBr3 QDs under heating or vigorous stirring. Aliquots of samples taken at different ultrasonic irradiation time intervals show a time-dependent redshift in the emission wavelength. This suggests the formation of CH3NH3PbCl3 QDs first, followed by the formation of CH3NH3PbBr3 QDs through ultrasonically promoted halide exchange. Moreover, mixed CH3NH3PbCl x Br3-x QDs with a tunable emission wavelength can also be prepared through this one-pot method by controlling the ultrasonic irradiation time. In comparison to the previous two-step method, the current one-pot method is simpler, less time-consuming and does not use flammable CH3NH2. The as-prepared CH3NH3PbBr3 QDs show a comparable photoluminescence (PL) quantum yield (QY) to that of the literature. What is more, the ultrasonic time-controlled emission wavelength of CH3NH3PbCl x Br3-x QDs also provides an alternative way of tuning QD emission to the traditional way of controlling the halide ratios.

  13. A new NH 3 orbital of the NH 3/Ni(110) surface observed by metastable quenching spectroscopy

    Science.gov (United States)

    Lee, Lihwa; Arias, Jose; Hanrahan, Ciaran; Martin, Richard M.; Metiu, Horia

    1986-01-01

    By using metastable quenching spectroscopy we have found a new NH 3 filled orbital (in the language of one electron theory) for NH 3/Ni(110), located at the Fermi level of the surface. The orbital is not observed when NH 3 is adsorbed on Ni(110), but it is detected for NH 3 adsorbed on polycrystalline Al.

  14. NH3 and NH4+ permeability in aquaporin-expressing Xenopus oocytes

    DEFF Research Database (Denmark)

    Holm, Lars M.; Jahn, Thomas Paul; Møller, Anders Laurell Blom

    2005-01-01

    We have shown recently, in a yeast expression system, that some aquaporins are permeable to ammonia. In the present study, we expressed the mammalian aquaporins AQP8, AQQP9, AQP3, AQP1 and a plant aquaporin TIP2;1 in Xenopus oocytes to study the transport of ammonia (NH3) and ammonium (NH4+) under...... inwards currents carried by NH4+. This conductivity increased as a sigmoid function of external [NH3]: for AQP8 at a bath pH (pH(e)) of 6.5, the conductance was abolished, at pH(e) 7.4 it was half maximal and at pH(e) 7.8 it saturated. NY4+ influx was associated with oocyte swelling. In comparison, native...... oocytes as well as AQP1 and tip2;1-expressing oocytes showed small currents that were associated with small and even negative volume changes. We conclude that AQP8, AQP9, AQP3, and TIP2;1, apart from being water channels, also support significant fluxes of NH3. These aquaporins could support NH4...

  15. Crystal structure of [UO2(NH35]NO3·NH3

    Directory of Open Access Journals (Sweden)

    Patrick Woidy

    2016-12-01

    Full Text Available Pentaammine dioxide uranium(V nitrate ammonia (1/1, [UO2(NH35]NO3·NH3, was obtained in the form of yellow crystals from the reaction of caesium uranyl nitrate, Cs[UO2(NO33], and uranium tetrafluoride, UF4, in dry liquid ammonia. The [UO2]+ cation is coordinated by five ammine ligands. The resulting [UO2(NH35] coordination polyhedron is best described as a pentagonal bipyramid with the O atoms forming the apices. In the crystal, numerous N—H...N and N—H...O hydrogen bonds are present between the cation, anion and solvent molecules, leading to a three-dimensional network.

  16. Different transport behaviors of NH4 (+) and NH3 in transmembrane cyclic peptide nanotubes.

    Science.gov (United States)

    Zhang, Mingming; Fan, Jianfen; Xu, Jian; Weng, Peipei; Lin, Huifang

    2016-10-01

    Two water-filled transmembrane cyclic peptide nanotubes (CPNTs) of 8×cyclo-(WL)n=4,5/POPE were chosen to investigate the dependences of the transport properties of the positive NH4 (+) and neutral NH3 on the channel radius. Molecular dynamic simulations revealed that molecular charge, size, ability to form H-bonds and channel radius all significantly influence the behaviors of NH4 (+) and NH3 in a CPNT. Higher electrostatic interactions, more H-bonds, and water-bridges were found in the NH4 (+) system, resulting in NH4 (+) meeting higher energy barriers, while NH3 can enter, exit and permeate the channels effortlessly. This work sheds a first light on the differences between the mechanisms of NH4 (+) and NH3 moving in a CPNT at an atomic level. Graphical Abstract Snapshot of the simulation system of NH4 (+)_octa-CPNT with an NH4 (+) initially positioned at one mouth of the tube, PMF profiles for single NH4 (+) ion and NH3 molecule moving through water-filled transmembrane CPNTs of 8×cyclo-(WL)n=4,5/POPE and sketch graphs of the possible H-bond forms of NH3 and NH4 (+) with the neighboring water.

  17. [The recent advances of HAM/TSP research].

    Science.gov (United States)

    Osame, M

    1999-12-01

    The ninth international conference on HTLVs and related disorders was held on April 5-9, 1999 at Kagoshima, Japan under the conference chairperson, Dr. Mitsuhiro Osame. In this meeting, world-wide epidemiological data on HTLV-I carriers, ATL patients, and HAM/TSP patients were summarized as shown in the table. The total number of them was supposed to be more than 2.2 millions, 1,200, and 3,000, respectively. To elucidate the localization of HTLV-I proviral DNA directly, double staining using immunohistochemistry and PCR in situ hybridization in the spinal cords of HAM/TSP patients were performed. HTLV-I proviral DNA was localized only to OPD 4-positive cells (Matsuoka et al, 1998). The localization of HTLV-I messenger RNA was the same (Moritoyo et al, 1996). A novel technique to detect HTLV-I tax protein was also developed. In HAM/TSP patients, 0.04-1.16% of the CSF cells and 0.02-0.54% of PBMCs were positive for HTLV-I tax protein (Moritoyo et al, 1999). It was also hypothesized that HLA alleles control HTLV-I proviral load and thus influence susceptibility to HAM/TSP. Two hundred and thirty-two cases of HAM/TSP were compared with 201 randomly selected HTLV-I seropositive asymptomatic blood donors. It was shown that, after infection with HTLV-I, the class I allele HLA-A*02 halves the odds of HAM/TSP (p doubled the odds of HAM/TSP in the absence of the protective effect of HLA-A*02 (Jeffery and Usuku et al, 1999).

  18. Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants.

    Science.gov (United States)

    Ariz, Idoia; Cruz, Cristina; Moran, Jose F; González-Moro, María B; García-Olaverri, Carmen; González-Murua, Carmen; Martins-Loução, Maria A; Aparicio-Tejo, Pedro M

    2011-05-16

    In plants, nitrate (NO3-) nutrition gives rise to a natural N isotopic signature (δ15N), which correlates with the δ15N of the N source. However, little is known about the relationship between the δ15N of the N source and the 14N/15N fractionation in plants under ammonium (NH4+) nutrition. When NH4+ is the major N source, the two forms, NH4+ and NH3, are present in the nutrient solution. There is a 1.025 thermodynamic isotope effect between NH3 (g) and NH4+ (aq) which drives to a different δ15N. Nine plant species with different NH4+-sensitivities were cultured hydroponically with NO3- or NH4+ as the sole N sources, and plant growth and δ15N were determined. Short-term NH4+/NH3 uptake experiments at pH 6.0 and 9.0 (which favours NH3 form) were carried out in order to support and substantiate our hypothesis. N source fractionation throughout the whole plant was interpreted on the basis of the relative transport of NH4+ and NH3. Several NO3--fed plants were consistently enriched in 15N, whereas plants under NH4+ nutrition were depleted of 15N. It was shown that more sensitive plants to NH4+ toxicity were the most depleted in 15N. In parallel, N-deficient pea and spinach plants fed with 15NH4+ showed an increased level of NH3 uptake at alkaline pH that was related to the 15N depletion of the plant. Tolerant to NH4+ pea plants or sensitive spinach plants showed similar trend on 15N depletion while slight differences in the time kinetics were observed during the initial stages. The use of RbNO3 as control discarded that the differences observed arise from pH detrimental effects. This article proposes that the negative values of δ15N in NH4+-fed plants are originated from NH3 uptake by plants. Moreover, this depletion of the heavier N isotope is proportional to the NH4+/NH3 toxicity in plants species. Therefore, we hypothesise that the low affinity transport system for NH4+ may have two components: one that transports N in the molecular form and is associated with

  19. Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants

    Science.gov (United States)

    2011-01-01

    Background In plants, nitrate (NO3-) nutrition gives rise to a natural N isotopic signature (δ15N), which correlates with the δ15N of the N source. However, little is known about the relationship between the δ15N of the N source and the 14N/15N fractionation in plants under ammonium (NH4+) nutrition. When NH4+ is the major N source, the two forms, NH4+ and NH3, are present in the nutrient solution. There is a 1.025 thermodynamic isotope effect between NH3 (g) and NH4+ (aq) which drives to a different δ15N. Nine plant species with different NH4+-sensitivities were cultured hydroponically with NO3- or NH4+ as the sole N sources, and plant growth and δ15N were determined. Short-term NH4+/NH3 uptake experiments at pH 6.0 and 9.0 (which favours NH3 form) were carried out in order to support and substantiate our hypothesis. N source fractionation throughout the whole plant was interpreted on the basis of the relative transport of NH4+ and NH3. Results Several NO3--fed plants were consistently enriched in 15N, whereas plants under NH4+ nutrition were depleted of 15N. It was shown that more sensitive plants to NH4+ toxicity were the most depleted in 15N. In parallel, N-deficient pea and spinach plants fed with 15NH4+ showed an increased level of NH3 uptake at alkaline pH that was related to the 15N depletion of the plant. Tolerant to NH4+ pea plants or sensitive spinach plants showed similar trend on 15N depletion while slight differences in the time kinetics were observed during the initial stages. The use of RbNO3 as control discarded that the differences observed arise from pH detrimental effects. Conclusions This article proposes that the negative values of δ15N in NH4+-fed plants are originated from NH3 uptake by plants. Moreover, this depletion of the heavier N isotope is proportional to the NH4+/NH3 toxicity in plants species. Therefore, we hypothesise that the low affinity transport system for NH4+ may have two components: one that transports N in the

  20. Effective identification of (NH4)2CO3 and NH4HCO3 concentrations in NaHCO3 regeneration process from desulfurized waste.

    Science.gov (United States)

    Govindan, Muthuraman; Karunakaran, Kannan; Nallasamy, Palanisami; Moon, Il Shik

    2015-01-01

    This work describes the quantitative analysis of (NH4)2CO3 and NH4HCO3 using a simple solution phase titration method. Back titration results at various (NH4)2CO3-NH4HCO3 ratios demonstrated that 6:4 ratio caused a 3% error in their differentiation, but very high errors were found at other ratios. A similar trend was observed for the double indicator method, especially when strong acid HCl was used as a titrant, where still less errors (2.5%) at a middle ratio of (NH4)2CO3-NH4HCO3 was found. Remaining ratios with low (NH4)2CO3 (2:8, 4:6) show high +ve error (found concentration is less) and high (NH4)2CO3 (7:3, 8:2, and 9:1) show high -ve error (found concentration is higher) and vice versa for NH4HCO3. In replacement titration using Na2SO4, at both higher end ratios of (NH4)2CO3-NH4HCO3 (2:8 and 9:1), both -ve and +ve errors were minimized to 75% by partial equilibrium arrest between (NH4)2CO3 and NH2COONH4, instead of more than 100% observed in back titration and only double indicator methods. In the presence of (NH4)2SO4 both -ve and +ve error% are completely reduced to 3±1 at ratios 2:8, 4:6, and 6:4 of (NH4)2CO3-NH4HCO3, which demonstrates that the equilibrium transformation between NH2COONH4 and (NH4)2CO3 is completely controlled. The titration conducted at lower temperature (5 °C) in the presence of (NH4)2SO4 at higher ratios of (NH4)2CO3-NH4HCO3 (7:3, 8:2,and 9:1) shows complete minimization of both -ve and +ve errors to 2±1%, which explains the complete arresting of equilibrium transformation. Finally, the developed method shows 2±1% error in differentiation of CO3(2-) and HCO3(-) in the regeneration process of NaHCO3 from crude desulfurized sample. The developed method is more promising to differentiate CO3(2-) and HCO3(-) in industrial applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants

    Directory of Open Access Journals (Sweden)

    Martins-Loução Maria A

    2011-05-01

    Full Text Available Abstract Background In plants, nitrate (NO3- nutrition gives rise to a natural N isotopic signature (δ15N, which correlates with the δ15N of the N source. However, little is known about the relationship between the δ15N of the N source and the 14N/15N fractionation in plants under ammonium (NH4+ nutrition. When NH4+ is the major N source, the two forms, NH4+ and NH3, are present in the nutrient solution. There is a 1.025 thermodynamic isotope effect between NH3 (g and NH4+ (aq which drives to a different δ15N. Nine plant species with different NH4+-sensitivities were cultured hydroponically with NO3- or NH4+ as the sole N sources, and plant growth and δ15N were determined. Short-term NH4+/NH3 uptake experiments at pH 6.0 and 9.0 (which favours NH3 form were carried out in order to support and substantiate our hypothesis. N source fractionation throughout the whole plant was interpreted on the basis of the relative transport of NH4+ and NH3. Results Several NO3--fed plants were consistently enriched in 15N, whereas plants under NH4+ nutrition were depleted of 15N. It was shown that more sensitive plants to NH4+ toxicity were the most depleted in 15N. In parallel, N-deficient pea and spinach plants fed with 15NH4+ showed an increased level of NH3 uptake at alkaline pH that was related to the 15N depletion of the plant. Tolerant to NH4+ pea plants or sensitive spinach plants showed similar trend on 15N depletion while slight differences in the time kinetics were observed during the initial stages. The use of RbNO3 as control discarded that the differences observed arise from pH detrimental effects. Conclusions This article proposes that the negative values of δ15N in NH4+-fed plants are originated from NH3 uptake by plants. Moreover, this depletion of the heavier N isotope is proportional to the NH4+/NH3 toxicity in plants species. Therefore, we hypothesise that the low affinity transport system for NH4+ may have two components: one that

  2. Aquaporin 4 as a NH3 Channel

    DEFF Research Database (Denmark)

    Assentoft, Mette; Kaptan, Shreyas; Schneider, Hans-Peter

    2016-01-01

    -brain-interface, participate in the exchange of ammonia, which is required to sustain the glutamate-glutamine cycle. Here we observe that AQP4-expressing Xenopus oocytes display a reflection coefficient NH4Cl at pH 8.0, at which pH an increased amount of the ammonia occurs in the form of NH3 Taken together with an NH4......Cl-mediated intracellular alkalization (or lesser acidification) of AQP4-expressing oocytes, these data suggest that NH3 is able to permeate the pore of AQP4. Exposure to NH4Cl increased the membrane currents to a similar extent in uninjected oocytes and in oocytes expressing AQP4, indicating...... that the ionic NH4 (+) did not permeate AQP4. Molecular dynamics simulations revealed partial pore permeation events of NH3 but not of NH4 (+) and a reduced energy barrier for NH3 permeation through AQP4 compared with that of a cholesterol-containing lipid bilayer, suggesting AQP4 as a favored transmembrane...

  3. Real-time observation of formation and relaxation dynamics of NH4 in (CH3OH)m(NH3)n clusters.

    Science.gov (United States)

    Yamada, Yuji; Nishino, Yoko; Fujihara, Akimasa; Ishikawa, Haruki; Fuke, Kiyokazu

    2009-03-26

    The formation and relaxation dynamics of NH4(CH3OH)m(NH3)n clusters produced by photolysis of ammonia-methanol mixed clusters has been observed by a time-resolved pump-probe method with femtosecond pulse lasers. From the detailed analysis of the time evolutions of the protonated cluster ions, NH4(+)(CH3OH)m(NH3)n, the kinetic model has been constructed, which consists of sequential three-step reaction: ultrafast hydrogen-atom transfer producing the radical pair (NH4-NH2)*, the relaxation process of radical-pair clusters, and dissociation of the solvated NH4 clusters. The initial hydrogen transfer hardly occurs between ammonia and methanol, implying the unfavorable formation of radical pair, (CH3OH2-NH2)*. The remarkable dependence of the time constants in each step on the number and composition of solvents has been explained by the following factors: hydrogen delocalization within the clusters, the internal conversion of the excited-state radical pair, and the stabilization of NH4 by solvation. The dependence of the time profiles on the probe wavelength is attributed to the different ionization efficiency of the NH4(CH3OH)m(NH3)n clusters.

  4. NMR Spectroscopic Characterization of Methylcobalt(III) Compounds with Classical Ligands. Crystal Structures of [Co(NH(3))(5)(CH(3))]S(2)O(6), trans-[Co(en)(2)(NH(3))(CH(3))]S(2)O(6) (en = 1,2-Ethanediamine), and [Co(NH(3))(6)]-mer,trans-[Co(NO(2))(3)(NH(

    DEFF Research Database (Denmark)

    Kofod, Pauli; Harris, Pernille; Larsen, Sine

    1997-01-01

    magnetic resonance spectroscopy and by absorption spectroscopy. Single-crystal X-ray structure determinations at 122.0(5) K were performed on [Co(NH(3))(5)(CH(3))]S(2)O(6) (1), trans-[Co(en)(2)(NH(3))(CH(3))]S(2)O(6) (2), and [Co(NH(3))(6)]-mer,trans-[Co(NO(2))(3)(NH(3))(2)(CH(3))](2)-trans-[Co(NO(2...

  5. A liquid-based eutectic system: LiBH4·NH 3-nNH3BH3 with high dehydrogenation capacity at moderate temperature

    KAUST Repository

    Tan, Yingbin; Guo, Yanhui; Li, Shaofeng; Sun, Weiwei; Zhu, Yihan; Li, Qi; Yu, Xuebin

    2011-01-01

    A novel eutectic hydrogen storage system, LiBH4·NH 3-nNH3BH3, which exists in a liquid state at room temperature, was synthesized through a simple mixing of LiBH 4·NH3 and NH3BH3 (AB). In the temperature range of 90-110 °C, the eutectic system

  6. Photostriction of CH3NH3PbBr3 Perovskite Crystals

    KAUST Repository

    Wei, Tzu-Chiao

    2017-07-17

    Organic-inorganic hybrid perovskite materials exhibit a variety of physical properties. Pronounced coupling between phonon, organic cations, and the inorganic framework suggest that these materials exhibit strong light-matter interactions. The photoinduced strain of CH3 NH3 PbBr3 is investigated using high-resolution and contactless in situ Raman spectroscopy. Under illumination, the material exhibits large blue shifts in its Raman spectra that indicate significant structural deformations (i.e., photostriction). From these shifts, the photostrictive coefficient of CH3 NH3 PbBr3 is calculated as 2.08 × 10-8 m2 W-1 at room temperature under visible light illumination. The significant photostriction of CH3 NH3 PbBr3 is attributed to a combination of the photovoltaic effect and translational symmetry loss of the molecular configuration via strong translation-rotation coupling. Unlike CH3 NH3 PbI3 , it is noted that the photostriction of CH3 NH3 PbBr3 is extremely stable, demonstrating no signs of optical decay for at least 30 d. These results suggest the potential of CH3 NH3 PbBr3 for applications in next-generation optical micro-electromechanical devices.

  7. Investigation on thermal evaporated CH3NH3PbI3 thin films

    Directory of Open Access Journals (Sweden)

    Youzhen Li

    2015-09-01

    Full Text Available CH3NH3I, PbI2 and CH3NH3PbI3 films were fabricated by evaporation and characterized with X-ray Photoelectron Spectroscopy (XPS and X-ray diffraction (XRD. The XPS results indicate that the PbI2 and CH3NH3PbI3 films are more uniform and stable than the CH3NH3I film. The atomic ratio of the CH3NH3I, PbI2 and CH3NH3PbI3 films are C:N:I=1.00:1.01:0.70, Pb:I= 1.00:1.91 and C: N: Pb: I = 1.29:1.07:1.00:2.94, respectively. The atomic ratio of CH3NH3PbI3 is very close to that of the ideal perovskite. Small angle x-ray diffraction results demonstrate that the as evaporated CH3NH3PbI3 film is crystalline. The valence band maximum (VBM and work function (WF of the CH3NH3PbI3 film are about 0.85eV and 4.86eV, respectively.

  8. A liquid-based eutectic system: LiBH4·NH 3-nNH3BH3 with high dehydrogenation capacity at moderate temperature

    KAUST Repository

    Tan, Yingbin

    2011-01-01

    A novel eutectic hydrogen storage system, LiBH4·NH 3-nNH3BH3, which exists in a liquid state at room temperature, was synthesized through a simple mixing of LiBH 4·NH3 and NH3BH3 (AB). In the temperature range of 90-110 °C, the eutectic system showed significantly improved dehydrogenation properties compared to the neat AB and LiBH 4·NH3 alone. For example, in the case of the LiBH4·NH3/AB with a mole ratio of 1:3, over 8 wt.% hydrogen could be released at 90 °C within 4 h, while only 5 wt.% hydrogen released from the neat AB at the same conditions. Through a series of experiments it has been demonstrated that the hydrogen release of the new system is resulted from an interaction of AB and the NH3 group in the LiBH4·NH3, in which LiBH4 works as a carrier of ammonia and plays a crucial role in promoting the interaction between the NH3 group and AB. The enhanced dehydrogenation of LiBH 4·NH3/AB may result from the polar liquid state reaction environments and the initially promoted formation of the diammoniate of diborane, which will facilitate the B-H⋯H-N interaction between LiBH4·NH3 and AB. Kinetics analysis revealed that the rate-controlling steps of the dehydrogenation process are three-dimensional diffusion of hydrogen at temperatures ranging from 90 to 110 °C. This journal is © The Royal Society of Chemistry.

  9. Thin-Film Transformation of NH4 PbI3 to CH3 NH3 PbI3 Perovskite: A Methylamine-Induced Conversion-Healing Process.

    Science.gov (United States)

    Zong, Yingxia; Zhou, Yuanyuan; Ju, Minggang; Garces, Hector F; Krause, Amanda R; Ji, Fuxiang; Cui, Guanglei; Zeng, Xiao Cheng; Padture, Nitin P; Pang, Shuping

    2016-11-14

    Methylamine-induced thin-film transformation at room-temperature is discovered, where a porous, rough, polycrystalline NH 4 PbI 3 non-perovskite thin film converts stepwise into a dense, ultrasmooth, textured CH 3 NH 3 PbI 3 perovskite thin film. Owing to the beneficial phase/structural development of the thin film, its photovoltaic properties undergo dramatic enhancement during this NH 4 PbI 3 -to-CH 3 NH 3 PbI 3 transformation process. The chemical origins of this transformation are studied at various length scales. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. NEW HIGH STRENGTH AND FASTER DRILLING TSP DIAMOND CUTTERS

    Energy Technology Data Exchange (ETDEWEB)

    Robert Radtke

    2006-01-31

    The manufacture of thermally stable diamond (TSP) cutters for drill bits used in petroleum drilling requires the brazing of two dissimilar materials--TSP diamond and tungsten carbide. The ENDURUS{trademark} thermally stable diamond cutter developed by Technology International, Inc. exhibits (1) high attachment (shear) strength, exceeding 345 MPa (50,000 psi), (2) TSP diamond impact strength increased by 36%, (3) prevents TSP fracture when drilling hard rock, and (4) maintains a sharp edge when drilling hard and abrasive rock. A novel microwave brazing (MWB) method for joining dissimilar materials has been developed. A conventional braze filler metal is combined with microwave heating which minimizes thermal residual stress between materials with dissimilar coefficients of thermal expansion. The process results in preferential heating of the lower thermal expansion diamond material, thus providing the ability to match the thermal expansion of the dissimilar material pair. Methods for brazing with both conventional and exothermic braze filler metals have been developed. Finite element modeling (FEM) assisted in the fabrication of TSP cutters controllable thermal residual stress and high shear attachment strength. Further, a unique cutter design for absorbing shock, the densification of otherwise porous TSP diamond for increased mechanical strength, and diamond ion implantation for increased diamond fracture resistance resulted in successful drill bit tests.

  11. Role of NH3 and NH4+ transporters in renal acid-base transport.

    Science.gov (United States)

    Weiner, I David; Verlander, Jill W

    2011-01-01

    Renal ammonia excretion is the predominant component of renal net acid excretion. The majority of ammonia excretion is produced in the kidney and then undergoes regulated transport in a number of renal epithelial segments. Recent findings have substantially altered our understanding of renal ammonia transport. In particular, the classic model of passive, diffusive NH3 movement coupled with NH4+ "trapping" is being replaced by a model in which specific proteins mediate regulated transport of NH3 and NH4+ across plasma membranes. In the proximal tubule, the apical Na+/H+ exchanger, NHE-3, is a major mechanism of preferential NH4+ secretion. In the thick ascending limb of Henle's loop, the apical Na+-K+-2Cl- cotransporter, NKCC2, is a major contributor to ammonia reabsorption and the basolateral Na+/H+ exchanger, NHE-4, appears to be important for basolateral NH4+ exit. The collecting duct is a major site for renal ammonia secretion, involving parallel H+ secretion and NH3 secretion. The Rhesus glycoproteins, Rh B Glycoprotein (Rhbg) and Rh C Glycoprotein (Rhcg), are recently recognized ammonia transporters in the distal tubule and collecting duct. Rhcg is present in both the apical and basolateral plasma membrane, is expressed in parallel with renal ammonia excretion, and mediates a critical role in renal ammonia excretion and collecting duct ammonia transport. Rhbg is expressed specifically in the basolateral plasma membrane, and its role in renal acid-base homeostasis is controversial. In the inner medullary collecting duct (IMCD), basolateral Na+-K+-ATPase enables active basolateral NH4+ uptake. In addition to these proteins, several other proteins also contribute to renal NH3/NH4+ transport. The role and mechanisms of these proteins are discussed in depth in this review.

  12. Generation of nanopores during desorption of NH3 from Mg(NH3)6Cl2

    DEFF Research Database (Denmark)

    Hummelshøj, Jens Strabo; Sørensen, Rasmus Zink; Kostova, M.Y.

    2006-01-01

    It is shown that nanopores are formed during desorption of NH3 from Mg(NH3)6Cl2, which has been proposed as a hydrogen storage material. The system of nanopores facilitates the transport of desorbed ammonia away from the interior of large volumes of compacted storage material. DFT calculations sh...

  13. Communication: Equivalence between symmetric and antisymmetric stretching modes of NH3 in promoting H + NH3 → H2 + NH2 reaction

    Science.gov (United States)

    Song, Hongwei; Yang, Minghui; Guo, Hua

    2016-10-01

    Vibrational excitations of reactants sometimes promote reactions more effectively than the same amount of translational energy. Such mode specificity provides insights into the transition-state modulation of reactivity and might be used to control chemical reactions. We report here a state-of-the-art full-dimensional quantum dynamical study of the hydrogen abstraction reaction H + NH3 → H2 + NH2 on an accurate ab initio based global potential energy surface. This reaction serves as an ideal candidate to study the relative efficacies of symmetric and degenerate antisymmetric stretching modes. Strong mode specificity, particularly for the NH3 stretching modes, is demonstrated. It is further shown that nearly identical efficacies of the symmetric and antisymmetric stretching modes of NH3 in promoting the reaction can be understood in terms of local-mode stretching vibrations of the reactant molecule.

  14. Formation of simple nitrogen hydrides NH and NH2 at cryogenic temperatures through N + NH3NH + NH2 reaction: dark cloud chemistry of nitrogen.

    Science.gov (United States)

    Nourry, Sendres; Krim, Lahouari

    2016-07-21

    Although NH3 molecules interacting with ground state nitrogen atoms N((4)S) seem not to be a very reactive system without providing additional energy to initiate the chemical process, we show through this study that, in the solid phase, at very low temperature, NH3 + N((4)S) reaction leads to the formation of the amidogen radical NH2. Such a dissociation reaction previously thought to occur exclusively through UV photon or energetic particle irradiation is in this work readily occurring just by stimulating the mobility of N((4)S)-atoms in the 3-10 K temperature range in the solid sample. The N((4)S)-N((4)S) recombination may be the source of metastable molecular nitrogen N2(A), a reactive species which might trigger the NH3 dissociation or react with ground state nitrogen atoms N((4)S) to form excited nitrogen atoms N((4)P/(2)D) through energy transfer processes. Based on our obtained results, it is possible to propose reaction pathways to explain the NH2 radical formation which is the first step in the activation of stable species such as NH3, a chemical induction process that, in addition to playing an important role in the origin of molecular complexity in interstellar space, is known to require external energy supplies to occur in the gas phase.

  15. Projection of SO{sub 2}, NO{sub X}, NH{sub 3} and particle emissions - 2010-2030

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, O -K; Plejdrup, M; Winther, M; Hjorth Mikkelsen, M; Albrektsen, R; Nielsen, M; Fauser, P; Hoffmann, L; Hjelgaard, K; Gyldenkaerne, S

    2012-01-15

    This report contains a description of models and background data for projection of SO{sub 2}, NO{sub x}, NH{sub 3}, NMVOC, TSP, PM{sub 10} and PM{sub 25} for Denmark. The emissions are projected to 2030 using basic scenarios together with the expected results of a few individual policy measures. Official Danish forecasts of activity rates are used in the models for those sectors for which the forecasts are available, i.e. the latest official forecast from the Danish Energy Agency. The emission factors refer either to international guidelines or are country-specific and refer to Danish legislation, Danish research reports or calculations based on emission data from a considerable number of plants. The projection models are based on the same structure and method as the Danish emission inventories in order to ensure consistency. (Author)

  16. Rapid ammonia gas transport accounts for futile transmembrane cycling under NH3/NH4+ toxicity in plant roots.

    Science.gov (United States)

    Coskun, Devrim; Britto, Dev T; Li, Mingyuan; Becker, Alexander; Kronzucker, Herbert J

    2013-12-01

    Futile transmembrane NH3/NH4(+) cycling in plant root cells, characterized by extremely rapid fluxes and high efflux to influx ratios, has been successfully linked to NH3/NH4(+) toxicity. Surprisingly, the fundamental question of which species of the conjugate pair (NH3 or NH4(+)) participates in such fluxes is unresolved. Using flux analyses with the short-lived radioisotope (13)N and electrophysiological, respiratory, and histochemical measurements, we show that futile cycling in roots of barley (Hordeum vulgare) seedlings is predominately of the gaseous NH3 species, rather than the NH4(+) ion. Influx of (13)NH3/(13)NH4(+), which exceeded 200 µmol g(-1) h(-1), was not commensurate with membrane depolarization or increases in root respiration, suggesting electroneutral NH3 transport. Influx followed Michaelis-Menten kinetics for NH3 (but not NH4(+)), as a function of external concentration (Km = 152 µm, Vmax = 205 µmol g(-1) h(-1)). Efflux of (13)NH3/(13)NH4(+) responded with a nearly identical Km. Pharmacological characterization of influx and efflux suggests mediation by aquaporins. Our study fundamentally revises the futile-cycling model by demonstrating that NH3 is the major permeating species across both plasmalemma and tonoplast of root cells under toxicity conditions.

  17. Photostriction of CH3NH3PbBr3 Perovskite Crystals

    KAUST Repository

    Wei, Tzu-Chiao; Wang, Hsin-Ping; Li, Ting-You; Lin, Chun-Ho; Hsieh, Ying-Hui; Chu, Ying-Hao; He, Jr-Hau

    2017-01-01

    .e., photostriction). From these shifts, the photostrictive coefficient of CH3 NH3 PbBr3 is calculated as 2.08 × 10-8 m2 W-1 at room temperature under visible light illumination. The significant photostriction of CH3 NH3 PbBr3 is attributed to a combination

  18. Emissions of Volatile Organic Compounds (VOCs) from Animal Husbandry: Chemical Compositions, Separation of Sources and Animal Types

    Science.gov (United States)

    Yuan, B.; Coggon, M.; Koss, A.; Warneke, C.; Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; De Gouw, J. A.

    2016-12-01

    Concentrated animal feeding operations (CAFOs) are important sources of volatile organic compounds (VOCs) in the atmosphere. We used a hydronium ion time-of-flight chemical ionization mass spectrometer (H3O+ ToF-CIMS) to measure VOC emissions from CAFOs in the Northern Front Range of Colorado during an aircraft campaign (SONGNEX) for regional contributions and from a mobile laboratory sampling for chemical characterizations of individual animal feedlots. The main VOCs emitted from CAFOs include carboxylic acids, alcohols, carbonyls, phenolic species, sulfur- and nitrogen-containing species. Alcohols and carboxylic acids dominate VOC concentrations. Sulfur-containing and phenolic species become more important in terms of odor activity values and NO3 reactivity, respectively. The high time-resolution mobile measurements allow the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the increase of ethanol concentrations were primarily associated with feed storage and handling. We apply a multivariate regression analysis using NH3 and ethanol as tracers to attribute the relative importance of animal-related emissions (animal exhalation and waste) and feed-related emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls and carboxylic acids. Phenolic species and nitrogen-containing species are predominantly associated with animals and their waste. VOC ratios can be potentially used as indicators for the separation of emissions from dairy and beef cattle from the regional aircraft measurements.

  19. INCREASED VASOOCCLUSIVE CRISIS IN “O” BLOOD GROUP SICKLE CELL DISEASE PATIENTS: ASSOCIATION WITH UNDERLYING THROMBOSPONDIN LEVELS.

    Directory of Open Access Journals (Sweden)

    M. Al Huneini

    2017-04-01

    Full Text Available Abstract: Objectives: To explore the incidence of vaso-occlusive crisis (VOC in Blood Group “O” sickle cell disease (SCD patients, and correlate it with the blood group and thrombospondin (TSP levels. Methods: In 89 consecutive SCD patients, blood samples were obtained for vWF antigen, collagen binding activity, blood group typing, C-reactive protein, variant hemoglobin analysis (HPLC, Serum TSP 1 and TSP 2 levels, complete blood counts, liver function tests, LDH and renal function tests during VOC episodes and in steady state conditions. Results: In the steady state SCD patients (n=72, “O” blood group patients (n=37 showed significantly higher median serum TSP 1 and TSP 2 levels than the non “O” blood group patients [n=35] [p <0.05, Mann-Whitney test], with an inverse relation between VWF:Ag, Factor VIII:C and TSP levels. Furthermore, the serum TSP 1 and TSP 2 levels were significantly higher in patients presenting with acute VOC [n=17], and in those with repeated VOC’s (group 1, n=16 especially amongst those patients with blood group “O” [p, <0.05, Mann-Whitney test]. Conclusions: The study shows that there was an inverse relation between TSP and vWF levels, in blood group “O” SCD patients with an upregulation of the TSP levels. Expectedly, during active VOC crisis, the TSP 1 and TSP 2 levels were significantly elevated.    Key Words: VOC; SCD; TSP; vWD; Blood groups

  20. Pilot-scale testing of renewable biocatalyst for swine manure treatment and mitigation of odorous VOCs, ammonia and hydrogen sulfide emissions

    Science.gov (United States)

    Maurer, Devin L.; Koziel, Jacek A.; Bruning, Kelsey; Parker, David B.

    2017-02-01

    Comprehensive control of odors, hydrogen sulfide (H2S), ammonia (NH3), and greenhouse gas (GHG) emissions associated with swine production is a critical need. A pilot-scale experiment was conducted to evaluate surface-applied soybean peroxidase (SBP) and calcium peroxide (CaO2) as a manure additive to mitigate emissions of odorous volatile organic compounds (VOC) including dimethyl disulfide/methanethiol (DMDS/MT), dimethyl trisulfide, n-butyric acid, valeric acid, isovaleric acid, p-cresol, indole, and skatole. The secondary impact on emissions of NH3, H2S, and GHG was also measured. The SBP was tested at four treatments (2.28-45.7 kg/m2 manure) with CaO2 (4.2% by weight of SBP) over 137 days. Significant reductions in VOC emissions were observed: DMDS/MT (36.2%-84.7%), p-cresol (53.1%-89.5%), and skatole (63.2%-92.5%). There was a corresponding significant reduction in NH3 (14.6%-67.6%), and significant increases in the greenhouse gases CH4 (32.7%-232%) and CO2 (20.8%-124%). The remaining emissions (including N2O) were not statistically different. At a cost relative to 0.8% of a marketed hog it appears that SBP/CaO2 treatment could be a promising option at the lowest (2.28 kg/m2) treatment rate for reducing odorous gas and NH3 emissions at swine operations, and field-scale testing is warranted.

  1. NH4+-NH3 removal from simulated wastewater using UV-TiO2 photocatalysis: effect of co-pollutants and pH.

    Science.gov (United States)

    Vohra, M S; Selimuzzaman, S M; Al-Suwaiyan, M S

    2010-05-01

    The main objective of the present study was to investigate the efficiency of titanium dioxide (TiO2) assisted photocatalytic degradation (PCD) process for the removal of ammonium-ammonia (NH4(+)-NH3) from the aqueous phase and in the presence of co-pollutants thiosulfate (S2O3(2-)) and p-cresol (C6H4CH3OH) under varying mixed conditions. For the NH4(+)-NH3 only PCD experiments, results showed higher NH4 -NH3 removal at pH 12 compared to pH 7 and 10. For the binary NH4(+)-NH3/S2O3(2-) studies the respective results indicated a significant lowering in NH4(+)-NH3 PCD in the presence of S2O32- at pH 7/12 whereas at pH 10 a marked increase in NH4(+)-NH3 removal transpired. A similar trend was noted for the p-cresol/NH4(+)-NH3 binary system. Comparing findings from the binary (NH4(+)-NH3/S2O3(2-) and p-cresol/NH4(+)-NH3) and tertiary (NH4(+)-NH3/S2O3(2-)/p-cresol) systems, at pH 10, showed fastest NH4(+)-NH3 removal transpiring for the tertiary system as compared to the binary systems, whereas both the binary systems indicated comparable NH4(+)-NH3 removal trends. The respective details have been discussed.

  2. Projection of SO{sub 2}, NO{sub X}, NMVOC, NH{sub 3} and particle emissions - 2005 to 2030

    Energy Technology Data Exchange (ETDEWEB)

    Boll Illerup, J; Nielsen, Ole-Kenneth; Winther, M; Hjorth Mikkelsen, M; Nielsen, Malene; Fauser, P; Gyldenkaerne, S

    2008-05-15

    This report contains a description of models and background data for projection of SO{sub 2}, NO{sub X}, NH{sub 3}, NMVOC, TSP, PM{sub 10} and PM{sub 2.5} for Denmark. The emissions are projected to 2030 using basic scenarios together with the expected results of a few individual policy measures. Official Danish forecasts of activity rates are used in the models for those sectors for which the forecasts are available, i.e. the latest official forecast from the Danish Energy Authority. The emission factors refer to international guidelines and some are country-specific and refer to Danish legislation, Danish research reports or calculations based on emission data from a considerable number of plants. The projection models are based on the same structure and method as the Danish emission inventories in order to ensure consistency. (au)

  3. Imaging a multidimensional multichannel potential energy surface: Photodetachment of H(-)(NH3) and NH4 (.).

    Science.gov (United States)

    Hu, Qichi; Song, Hongwei; Johnson, Christopher J; Li, Jun; Guo, Hua; Continetti, Robert E

    2016-06-28

    Probes of the Born-Oppenheimer potential energy surfaces governing polyatomic molecules often rely on spectroscopy for the bound regions or collision experiments in the continuum. A combined spectroscopic and half-collision approach to image nuclear dynamics in a multidimensional and multichannel system is reported here. The Rydberg radical NH4 and the double Rydberg anion NH4 (-) represent a polyatomic system for benchmarking electronic structure and nine-dimensional quantum dynamics calculations. Photodetachment of the H(-)(NH3) ion-dipole complex and the NH4 (-) DRA probes different regions on the neutral NH4 PES. Photoelectron energy and angular distributions at photon energies of 1.17, 1.60, and 2.33 eV compare well with quantum dynamics. Photoelectron-photofragment coincidence experiments indicate dissociation of the nascent NH4 Rydberg radical occurs to H + NH3 with a peak kinetic energy of 0.13 eV, showing the ground state of NH4 to be unstable, decaying by tunneling-induced dissociation on a time scale beyond the present scope of multidimensional quantum dynamics.

  4. Two-center three-electron bonding in ClNH{sub 3} revealed via helium droplet infrared laser Stark spectroscopy: Entrance channel complex along the Cl + NH{sub 3} → ClNH{sub 2} + H reaction

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Christopher P.; Douberly, Gary E., E-mail: douberly@uga.edu [Department of Chemistry, University of Georgia, Athens, Georgia 30602-2556 (United States); Xie, Changjian; Guo, Hua [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Kaufmann, Matin [Department of Physical Chemistry II, Ruhr-University Bochum, D-44801 Bochum (Germany)

    2016-04-28

    Pyrolytic dissociation of Cl{sub 2} is employed to dope helium droplets with single Cl atoms. Sequential addition of NH{sub 3} to Cl-doped droplets leads to the formation of a complex residing in the entry valley to the substitution reaction Cl + NH{sub 3} → ClNH{sub 2} + H. Infrared Stark spectroscopy in the NH stretching region reveals symmetric and antisymmetric vibrations of a C{sub 3v} symmetric top. Frequency shifts from NH{sub 3} and dipole moment measurements are consistent with a ClNH{sub 3} complex containing a relatively strong two-center three-electron (2c–3e) bond. The nature of the 2c–3e bonding in ClNH{sub 3} is explored computationally and found to be consistent with the complexation-induced blue shifts observed experimentally. Computations of interconversion pathways reveal nearly barrierless routes to the formation of this complex, consistent with the absence in experimental spectra of two other complexes, NH{sub 3}Cl and Cl–HNH{sub 2}, which are predicted in the entry valley to the hydrogen abstraction reaction Cl + NH{sub 3} → HCl + NH{sub 2}.

  5. Comparative genomic and physiological analysis of nutrient response to NH4+, NH4+:NO3- and NO3- in barley seedlings.

    Science.gov (United States)

    Lopes, Marta S; Araus, José L

    2008-09-01

    Long-term differences in photosynthesis, respiration and growth of plants receiving distinct nitrogen (N) sources imply that N metabolism generates signals that regulate metabolism and development. The molecular basis of these signals remains unclear. Here we studied the gene expression profiles of barley (Hordeum vulgare L. cv. Graphic) seedlings fertilized either with ammonium (NH4+), with ammonium and nitrate (NH4+:NO3-), or with nitrate (NO3-) only. Our transcriptome analysis after 48 h of growth in these N sources showed major changes in the expression of genes involved in N metabolism (nitrate reductase), signalling (protein kinases and protein phosphatases), photosynthesis (chlorophyll a/b-binding protein and a PsbQ domain), where increases in NO3- as compared with NH4+ were observed. Moreover, NH4+ assimilation induced genes participating in C and sugars metabolism (phosphoglycerate kinase, glucosyltranferase and galactokinase), respiration (cytochrome c oxidase), protein fate (heat shock proteins) and development (MTN3-like protein). These changes in gene expression could well explain the long-term growth depression observed in NH4+ plants. Even if a few genes participating in protein fate (proteases) and development (OsNAC5) were upregulated in NH4+ as compared with NH4+:NO3-, the general pattern of expression was quite similar between these two N sources. Taken together, these results indicated that other downstream mechanisms should be involved in the synergetic long-term response of NH4+:NO3-.

  6. Rate-based modelling of combined SO2 removal and NH3 recycling integrated with an aqueous NH3-based CO2 capture process

    International Nuclear Information System (INIS)

    Li, Kangkang; Yu, Hai; Qi, Guojie; Feron, Paul; Tade, Moses; Yu, Jingwen; Wang, Shujuan

    2015-01-01

    Highlights: • A rigorous, rate-based model for an NH 3 –CO 2 –SO 2 –H 2 O system was developed. • Model predictions are in good agreement with pilot plant results. • >99.9% of SO 2 was captured and >99.9% of slipped ammonia was reused. • The process is highly adaptable to the variations of SO 2 /NH 3 level, temperatures. - Abstract: To reduce the costs of controlling emissions from coal-fired power stations, we propose an advanced and effective process of combined SO 2 removal and NH 3 recycling, which can be integrated with the aqueous NH 3 -based CO 2 capture process to simultaneously achieve SO 2 and CO 2 removal, NH 3 recycling and flue gas cooling in one process. A rigorous, rate-based model for an NH 3 –CO 2 –SO 2 –H 2 O system was developed and used to simulate the proposed process. The model was thermodynamically and kinetically validated by experimental results from the open literature and pilot-plant trials, respectively. Under typical flue gas conditions, the proposed process has SO 2 removal and NH 3 reuse efficiencies of >99.9%. The process is strongly adaptable to different scenarios such as high SO 2 levels in flue gas, high NH 3 levels from the CO 2 absorber and high flue gas temperatures, and has a low energy requirement. Because the process simplifies flue gas desulphurisation and resolves the problems of NH 3 loss and SO 2 removal, it could significantly reduce the cost of CO 2 and SO 2 capture by aqueous NH 3

  7. Synthesis, Resistivity, and Thermal Properties of the Cubic Perovskite NH 2CH=NH 2SnI 3and Related Systems

    Science.gov (United States)

    Mitzi, D. B.; Liang, K.

    1997-12-01

    Combining concentrated hydriodic acid solutions of tin(II) iodide and formamidine acetate in an inert atmosphere results in the precipitation of a new conducting organic-inorganic compound, NH 2CH=NH 2SnI 3, which at room temperature adopts a cubic perovskite structure. The lattice constant for NH 2CH=NH 2SnI 3is found to be a=6.316(1) Å, which is approximately 1.2% larger than that for the isostructural compound CH 3NH 3SnI 3. The electrical resistivity of a pressed pellet of the new compound exhibits semimetallic temperature dependence from 10 to 300 K, with evidence of a structural transition at approximately 75 K. NH 2CH=NH 2SnI 3begins to slowly decompose in an inert atmosphere at temperatures as low as 200°C, with bulk decomposition/melting occurring above 300°C. The properties of the formamidinium-based perovskite are compared with those of the related cubic (at room temperature) perovskite CH 3NH 3SnI 3and the mixed-cation system (CH 3NH 3) 1- x(NH 2CH=NH 2) xSnI 3.

  8. Rapid Ammonia Gas Transport Accounts for Futile Transmembrane Cycling under NH3/NH4+ Toxicity in Plant Roots1[C][W

    Science.gov (United States)

    Coskun, Devrim; Britto, Dev T.; Li, Mingyuan; Becker, Alexander; Kronzucker, Herbert J.

    2013-01-01

    Futile transmembrane NH3/NH4+ cycling in plant root cells, characterized by extremely rapid fluxes and high efflux to influx ratios, has been successfully linked to NH3/NH4+ toxicity. Surprisingly, the fundamental question of which species of the conjugate pair (NH3 or NH4+) participates in such fluxes is unresolved. Using flux analyses with the short-lived radioisotope 13N and electrophysiological, respiratory, and histochemical measurements, we show that futile cycling in roots of barley (Hordeum vulgare) seedlings is predominately of the gaseous NH3 species, rather than the NH4+ ion. Influx of 13NH3/13NH4+, which exceeded 200 µmol g–1 h–1, was not commensurate with membrane depolarization or increases in root respiration, suggesting electroneutral NH3 transport. Influx followed Michaelis-Menten kinetics for NH3 (but not NH4+), as a function of external concentration (Km = 152 µm, Vmax = 205 µmol g–1 h–1). Efflux of 13NH3/13NH4+ responded with a nearly identical Km. Pharmacological characterization of influx and efflux suggests mediation by aquaporins. Our study fundamentally revises the futile-cycling model by demonstrating that NH3 is the major permeating species across both plasmalemma and tonoplast of root cells under toxicity conditions. PMID:24134887

  9. Structural determinants of NH3 and NH4+ transport by mouse Rhbg, a renal Rh glycoprotein.

    Science.gov (United States)

    Abdulnour-Nakhoul, Solange; Le, Trang; Rabon, Edd; Hamm, L Lee; Nakhoul, Nazih L

    2016-12-01

    Renal Rhbg is localized to the basolateral membrane of intercalated cells and is involved in NH 3 /NH 4 + transport. The structure of Rhbg is not yet resolved; however, a high-resolution crystal structure of AmtB, a bacterial homolog of Rh, has been determined. We aligned the sequence of Rhbg to that of AmtB and identified important sites of Rhbg that may affect transport. Our analysis positioned three conserved amino acids, histidine 183 (H183), histidine 342 (H342), and tryptophan 230 (W230), within the hydrophobic pore where they presumably serve to control NH 3 transport. A fourth residue, phenylalanine 128 (F128) was positioned at the upper vestibule, presumably contributing to recruitment of NH 4 + We generated three mutations each of H183, H342, W230, and F128 and expressed them in frog oocytes. Immunolabeling showed that W230 and F128 mutants were localized to the cell membrane, whereas H183 and H342 staining was diffuse and mostly intracellular. To determine function, we compared measurements of NH 3 /NH 4 + and methyl amine (MA)/methyl ammonium (MA + )-induced currents, intracellular pH, and surface pH (pHs) among oocytes expressing the mutants, Rhbg, or injected with H 2 O. In H183 and W230 mutants, NH 4 + -induced current and intracellular acidification were inhibited compared with that of Rhbg, and MA-induced intracellular alkalinization was completely absent. Expression of H183A or W230A mutants inhibited NH 3 /NH 4 + - and MA/MA + -induced decrease in pHs to the level observed in H 2 O-injected oocytes. Mutations of F128 did not significantly affect transport of NH 3 or NH 4 + These data demonstrated that mutating H183 or W230 caused loss of function but not F128. H183 and H342 may affect membrane expression of the transporter.

  10. Deterministic algorithms for multi-criteria Max-TSP

    NARCIS (Netherlands)

    Manthey, Bodo

    2012-01-01

    We present deterministic approximation algorithms for the multi-criteria maximum traveling salesman problem (Max-TSP). Our algorithms are faster and simpler than the existing randomized algorithms. We devise algorithms for the symmetric and asymmetric multi-criteria Max-TSP that achieve ratios of

  11. CH3NH3Pb1-xMgxI3 perovskites as environmentally friendly photovoltaic materials

    Science.gov (United States)

    Zhang, Y. D.; Feng, J.

    2018-01-01

    In an effort to reduce the toxicity of Pb in perovskite solar cells, the band structures, electron and hole effective masses, and electronic and optical properties of the novel perovskites CH3NH3Pb1-xMgxI3 were predicted using density functional theory with the scalar relativistic generalized gradient approximation. The calculation results indicated that the introduction of the Mg component caused the band gaps of the CH3NH3Pb1-xMgxI3 compounds to exceed that of CH3NH3PbI3. The calculated absorption coefficients of the CH3NH3PbI3 and CH3NH3Pb1-xMgxI3 perovskites revealed that substituting 12.5 mol % of the Pb in CH3NH3PbI3 with Mg had little effect on the absorption ability. Surprisingly, it was also found that CH3NH3Pb0.75Mg0.25I3 retained up to 83% of the absorption performance relative to CH3NH3PbI3. This indicates that the amount of toxic Pb used in perovskite solar cells could be reduced by a quarter while retaining over 80% of the light-absorbing ability. In general, these novel CH3NH3Pb1-xMgxI3 (x ≤ 0.25) perovskites represent promising candidates for environmentally friendly light-harvesting materials for use in solar cells.

  12. Optical monitoring of CH3NH3PbI3 thin films upon atmospheric exposure

    International Nuclear Information System (INIS)

    Ghimire, Kiran; Zhao, Dewei; Cimaroli, Alex; Ke, Weijun; Yan, Yanfa; Podraza, Nikolas J

    2016-01-01

    CH 3 NH 3 PbI 3 perovskite films of interest for photovoltaic (PV) devices have been prepared by (i) vapor deposition and (ii) solution processing. Complex dielectric function ( ε   =   ε 1   +  i ε 2 ) spectra and structural parameters of the films have been extracted using near infrared to ultraviolet spectroscopic ellipsometry. In situ real time spectroscopic ellipsometry (RTSE) over a 48 h period has been performed on vapor deposited CH 3 NH 3 PbI 3 after the deposition in normal atmospheric laboratory ambient conditions. Analysis of RTSE data for vapor deposited CH 3 NH 3 PbI 3 film prepared under un-optimized conditions identifies phase segregated PbI 2 and CH 3 NH 3 I at the substrate/film interface and unreacted PbI 2 and CH 3 NH 3 I on the film surface. This analysis also provides the time dependence of the effective thicknesses of perovskite film, unreacted components, and phase segregated layers to track CH 3 NH 3 PbI 3 decomposition. (paper)

  13. Photovoltaic properties of Cu-doped CH3NH3PbI3 with perovskite structure

    Science.gov (United States)

    Shirahata, Yasuhiro; Oku, Takeo

    2017-01-01

    Photovoltaic properties of copper (Cu)-doped perovskite (CH3NH3PbCuxI3+x) photovoltaic devices with different Cu content were investigated. The CH3NH3PbCuxI3+x films were polycrystalline with a tetragonal system, and their lattice constants and crystallite size varied with Cu doping. Compared to conversion efficiencies of non-doped CH3NH3PbI3 photovoltaic device, those of CH3NH3PbCuxI3+x photovoltaic devises increased. The improvement of photovoltaic properties was attributed to partial substitution of Cu at the Pb sites.

  14. Pumping characteristics of sputter ion pump (SIP) and titanium sublimation pump (TSP) combination

    International Nuclear Information System (INIS)

    Ratnakala, K.C.; Patel, R.J.; Bhavsar, S.T.; Pandiyar, M.L.; Ramamurthi, S.S.

    1995-01-01

    For achieving hydrocarbon free, clean ultra high vacuum, SIP-TSP combination is one of the ideal choice for pumping. For the SRS facility in Centre for Advanced Technology (CAT), we are utilising this combination, enmass. For this purpose, two modules of these combination set-ups are assembled, one with the TSP as an integral part of SIP and the other, with TSP as a separate pump mounted on the top of SIP. The pump bodies were vacuum degassed at 700 degC at 10 -5 mbar for 3 hrs. An ultimate vacuum of 3 x 10 -11 mbar was achieved, after a bake-out at 250 degC for 4 hrs, followed by continuous SIP pumping for 48 hrs, with two TSP flashing at approximately 10 hrs interval. The pump-down patterns as well as the pressure-rise patterns are studied. (author). 2 refs., 5 figs

  15. On the growth of CH3NH3PbI3-xClx single crystal and characterization

    Science.gov (United States)

    Su, J.; Wang, W. F.; Lei, Y.; Zhang, L.; Xu, L. H.; Wang, D.; Lu, D.; Bai, Y.

    2018-05-01

    In this paper, CH3NH3PbI3-xClx crystal was grown by solution cooling method with CH3NH3I and PbCl2 as raw materials. Lead compounds and CH3NH3PbI3-xClx crystal with size about 6 mm × 4 mm × 2 mm were obtained. The chemical reactions with different CH3NH3I/PbCl2 ratios were analyzed. XPS shows the content of chlorine in CH3NH3PbI3-xClx is about 0.91%. PXRD, FT-IR, Raman and absorbance spectra were used to study the structure and optical properties of CH3NH3PbI3-xClx by comparing with CH3NH3PbI3 crystal. The CH3NH3PbI3-xClx crystal grown is of tetragonal structure with the lattice constants a = b = 8.8165 Å, c = 12.7920 Å and the bandgap value of 1.57 eV.

  16. [UO2(NH3)5]Br2·NH3: synthesis, crystal structure, and speciation in liquid ammonia solution by first-principles molecular dynamics simulations.

    Science.gov (United States)

    Woidy, Patrick; Bühl, Michael; Kraus, Florian

    2015-04-28

    Pentaammine dioxido uranium(VI) dibromide ammonia (1/1), [UO2(NH3)5]Br2·NH3, was synthesized in the form of yellow crystals by the reaction of uranyl bromide, UO2Br2, with dry liquid ammonia. The compound crystallizes orthorhombic in space group Cmcm and is isotypic to [UO2(NH3)5]Cl2·NH3 with a = 13.2499(2), b = 10.5536(1), c = 8.9126(1) Å, V = 1246.29(3) Å(3) and Z = 4 at 123 K. The UO2(2+) cation is coordinated by five ammine ligands and the coordination polyhedron can be best described as pentagonal bipyramid. Car-Parrinello molecular dynamics simulations are reported for [UO2(NH3)5](2+) in the gas phase and in liquid NH3 solution (using the BLYP density functional). According to free-energy simulations, solvation by ammonia has only a small effect on the uranyl-NH3 bond strength.

  17. Effect of Annealing Process on CH3NH3PbI3-XClX Film Morphology of Planar Heterojunction Perovskite Solar Cells with Optimal Compact TiO2 Layer

    Directory of Open Access Journals (Sweden)

    Dan Chen

    2017-01-01

    Full Text Available The morphology of compact TiO2 film used as an electron-selective layer and perovskite film used as a light absorption layer in planar perovskite solar cells has a significant influence on the photovoltaic performance of the devices. In this paper, the spin coating speed of the compact TiO2 is investigated in order to get a high-quality film and the compact TiO2 film exhibits pinhole- and crack-free films treated by 2000 rpm for 60 s. Furthermore, the effect of annealing process, including annealing temperature and annealing program, on CH3NH3PbI3-XClX film morphology is studied. At the optimal annealing temperature of 100°C, the CH3NH3PbI3-XClX morphology fabricated by multistep slow annealing method has smaller grain boundaries and holes than that prepared by one-step direct annealing method, which results in the reduction of grain boundary recombination and the increase of Voc. With all optimal procedures, a planar fluorine-doped tin oxide (FTO substrate/compact TiO2/CH3NH3PbI3-XClX/Spiro-MeOTAD/Au cell is prepared for an active area of 0.1 cm2. It has achieved a power conversion efficiency (PCE of 14.64%, which is 80.3% higher than the reference cell (8.12% PCE without optimal perovskite layer. We anticipate that the annealing process with optimal compact TiO2 layer would possibly become a promising method for future industrialization of planar perovskite solar cells.

  18. Water soluble ions in aerosols (TSP) : Characteristics, sources and seasonal variation over the central Himalayas, Nepal

    Science.gov (United States)

    Tripathee, Lekhendra; Kang, Shichang; Zhang, Qianggong; Rupakheti, Dipesh

    2016-04-01

    Atmspheric pollutants transported from South Asia could have adverse impact on the Himalayan ecosystems. Investigation of aerosol chemistry in the Himalayan region in Nepal has been limited on a temporal and spatial scale to date. Therefore, the water-soluble ionic composition of aerosol using TSP sampler was investigated for a year period from April 2013 to March 2014 at four sites Bode, Dhunche, Lumbini and Jomsom characterized as an urban, rural, semi-urban and remote sites in Nepal. During the study period, the highest concentration of major cation was Ca2+ with an average concentration of 8.91, 2.17, 7.85 and 6.42 μg m-3 and the highest concentration of major anion was SO42- with an average of 10.96, 4.06, 6.85 and 3.30 μg m-3 at Bode, Dhunche, Lumbini and Jomsom respectively. The soluble ions showed the decrease in concentrations from urban to the rural site. Correlations and PCA analysis suggested that that SO42-, NO3- and NH4+ were derived from the anthropogenic sources where as the Ca2+ and Mg2+ were from crustal sources. Our results also suggest that the largest acid neutralizing agent at our sampling sites in the central Himalayas are Ca2+ followed by NH4+. Seasonal variations of soluble ions in aerosols showed higher concentrations during pre-monsoon and winter (dry-periods) due to limited precipitation amount and lower concentrations during the monsoon which can be explained by the dilution effect, higher the precipitation lower the concentration. K+ which is regarded as the tracer of biomss burning had a significant peaks during pre-monsoon season when the forest fires are active around the regions. In general, the results of this study suggests that the atmospheric chemistry is influenced by natural and anthropogenic sources. Thus, soluble ionic concentrations in aerosols from central Himalayas, Nepal can provide a useful database to assess atmospheric environment and its impacts on human health and ecosystem in the southern side of central

  19. CH3NH3PbI3 based solar cell: Modified by antisolvent treatment

    Science.gov (United States)

    Nandi, Pronoy; Giri, Chandan; Bansode, Umesh; Topwal, D.

    2017-05-01

    Solar cells based on new class of organic inorganic hybrid perovskite CH3NH3PbI3 were prepared by Ethyl acetate (EA); antisolvent treatment for the first time. This treatment results in new morphology for CH3NH3PbI3 thin film. FESEM image shows microrod type structures of CH3NH3PbI3 after EA antisolvent treatment. Energy band diagram was constructed using photoluminescence and photoemission studies. A better power conversion efficiency was achieved in EA treated film compare to without EA treated film.

  20. 41 CFR 102-117.285 - What are my choices if a TSP's performance is not satisfactory?

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What are my choices if a TSP's performance is not satisfactory? 102-117.285 Section 102-117.285 Public Contracts and Property... are my choices if a TSP's performance is not satisfactory? You may choose to place a TSP in temporary...

  1. Enhanced protective efficacy of a chimeric form of the schistosomiasis vaccine antigen Sm-TSP-2.

    Directory of Open Access Journals (Sweden)

    Mark S Pearson

    Full Text Available The large extracellular loop of the Schistosoma mansoni tetraspanin, Sm-TSP-2, when fused to a thioredoxin partner and formulated with Freund's adjuvants, has been shown to be an efficacious vaccine against murine schistosomiasis. Moreover, Sm-TSP-2 is uniquely recognised by IgG(1 and IgG(3 from putatively resistant individuals resident in S. mansoni endemic areas in Brazil. In the present study, we expressed Sm-TSP-2 at high yield and in soluble form in E. coli without the need for a solubility enhancing fusion partner. We also expressed in E. coli a chimera called Sm-TSP-2/5B, which consisted of Sm-TSP-2 fused to the immunogenic 5B region of the hookworm aspartic protease and vaccine antigen, Na-APR-1. Sm-TSP-2 formulated with alum/CpG showed significant reductions in adult worm and liver egg burdens in two separate murine schistosomiasis challenge studies. Sm-TSP-2/5B afforded significantly greater protection than Sm-TSP-2 alone when both antigens were formulated with alum/CpG. The enhanced protection obtained with the chimeric fusion protein was associated with increased production of anti-Sm-TSP-2 antibodies and IL-4, IL-10 and IFN-γ from spleen cells of vaccinated animals. Sera from 666 individuals from Brazil who were infected with S. mansoni were screened for potentially deleterious IgE responses to Sm-TSP-2. Anti-Sm-TSP-2 IgE to this protein was not detected (also shown previously for Na-APR-1, suggesting that the chimeric antigen Sm-TSP-2/5B could be used to safely and effectively vaccinate people in areas where schistosomes and hookworms are endemic.

  2. Preparation of silver chloride nanoparticles by a mechanical treatment of the system NH4Cl−AgNO3NH4NO3

    Directory of Open Access Journals (Sweden)

    Farit Urakaev

    2014-08-01

    Full Text Available Silver chloride nanoparticles dispersed within ammonium nitrate matrix have been prepared though displacement mechanochemical reaction NH4Cl + AgNO3 + z NH4NO3 = (z+1 NH4 NO3 + AgCl at various z coefficients z1 = 7.22 and z2 = 3.64. The intermediate compound of NH4Ag(NO32 were recorded after mechanochemical processing of studied system. By using simultaneous TG and DSC measurements possibilities to prepare silver chloride in its free form have been discussed by using thermal treatment.

  3. CH3NH3Pb1−xMgxI3 perovskites as environmentally friendly photovoltaic materials

    Directory of Open Access Journals (Sweden)

    Y. D. Zhang

    2018-01-01

    Full Text Available In an effort to reduce the toxicity of Pb in perovskite solar cells, the band structures, electron and hole effective masses, and electronic and optical properties of the novel perovskites CH3NH3Pb1−xMgxI3 were predicted using density functional theory with the scalar relativistic generalized gradient approximation. The calculation results indicated that the introduction of the Mg component caused the band gaps of the CH3NH3Pb1−xMgxI3 compounds to exceed that of CH3NH3PbI3. The calculated absorption coefficients of the CH3NH3PbI3 and CH3NH3Pb1−xMgxI3 perovskites revealed that substituting 12.5 mol % of the Pb in CH3NH3PbI3 with Mg had little effect on the absorption ability. Surprisingly, it was also found that CH3NH3Pb0.75Mg0.25I3 retained up to 83% of the absorption performance relative to CH3NH3PbI3. This indicates that the amount of toxic Pb used in perovskite solar cells could be reduced by a quarter while retaining over 80% of the light-absorbing ability. In general, these novel CH3NH3Pb1−xMgxI3 (x ≤ 0.25 perovskites represent promising candidates for environmentally friendly light-harvesting materials for use in solar cells.

  4. Tropospheric VOC measurements by PTR-MS

    International Nuclear Information System (INIS)

    Hansel, A.; Wisthaler, A.; Graus, M.; Grabmer, W.

    2002-01-01

    Full text: O 3 is formed photochemically from the photolysis of NO 2 , and because O 3 reacts rapidly with NO these reactions result in a photoequilibrium between NO, NO 2 with no net formation or loss of O 3 , However, in the presence of volatile organic compounds (VOCs), the degradation reactions of VOCs lead to the formation of intermediate peroxy radicals which react with NO, converting NO to NO 2 , which then photolyze to form O 3 . Thus, in order to understand quantitatively tropospheric ozone chemistry, it is necessary to know the VOC distribution within the troposphere as well as VOC fluxes from individual sources. Examples will be presented how the use of Proton Transfer Reaction Mass Spectrometry (PTR-MS) has enhanced our understanding of anthropogenic VOC emissions, biosphere-atmosphere exchange processes, and photochemical processing of both anthropogenic and biogenic VOCs in the troposphere. (author)

  5. Parallel Changes in Intracellular Water Volume and pH Induced by NH3/NH4+ Exposure in Single Neuroblastoma Cells

    Directory of Open Access Journals (Sweden)

    Víctor M. Blanco

    2013-12-01

    Full Text Available Background: Increased blood levels of ammonia (NH3 and ammonium (NH4+, i.e. hyperammonemia, leads to cellular brain edema in humans with acute liver failure. The pathophysiology of this edema is poorly understood. This is partly due to incomplete understanding of the osmotic effects of the pair NH3/NH4+ at the cellular and molecular levels. Cell exposure to solutions containing NH3/NH4+ elicits changes in intracellular pH (pHi, which can in turn affect cell water volume (CWV by activating transport mechanisms that produce net gain or loss of solutes and water. The occurrence of CWV changes caused by NH3/NH4+ has long been suspected, but the mechanisms, magnitude and kinetics of these changes remain unknown. Methods: Using fluorescence imaging microscopy we measured, in real time, parallel changes in pHi and CWV caused by brief exposure to NH3/NH4+ of single cells (N1E-115 neuroblastoma or NG-108 neuroblastoma X glioma loaded with the fluorescent indicator BCECF. Changes in CWV were measured by exciting BCECF at its intracellular isosbestic wavelength (∼438 nm, and pHi was measured ratiometrically. Results: Brief exposure to isosmotic solutions (i.e. having the same osmolality as that of control solutions containing NH4Cl (0.5- 30 mM resulted in a rapid, dose-dependent swelling, followed by isosmotic regulatory volume decrease (iRVD. NH4Cl solutions in which either extracellular [NH3] or [NH4+] was kept constant while the other was changed by varying the pH of the solution, demonstrated that [NH3]o rather than [NH4+]o is the main determinant of the NH4Cl-induced swelling. The iRVD response was sensitive to the anion channel blocker NPPB, and partly dependent on external Ca2+. Upon removal of NH4Cl, cells shrank and displayed isosmotic regulatory volume increase (iRVI. Regulatory volume responses could not be activated by comparable CWV changes produced by anisosmotic solutions, suggesting that membrane stretch or contraction by themselves are

  6. The energy level alignment at the CH_3NH_3PbI_3/pentacene interface

    International Nuclear Information System (INIS)

    Ji, Gengwu; Zhao, Bin; Song, Fei; Zheng, Guanhaojie; Zhang, Xiaonan; Shen, Kongchao; Yang, Yingguo; Chen, Shi; Gao, Xingyu

    2017-01-01

    Highlights: • The Energy Level Alignment at the CH_3NH_3PbI_3/Pentacene Interface was resolved experimentally. • The downward band bending and the dipole found at the pentacene side would favorably drive holes away from the interface into pentacene. • A ∼0.7 eV offset between pentacene HOMO and CH_3NH_3PbI_3 VBM would be in favor of hole transfer whereas a ∼1.35 eV offset between pentacene LUMO and CH_3NH_3PbI_3 CBM should efficiently block the unwanted electron transfer from perovskite to pentacene. • Pentacene could be a viable hole transfer material candidate on perovskite to be explored in perovskite devices. - Abstract: Pentacene thin film on CH_3NH_3PbI_3 was studied by in-situ X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy to determine their interfacial energy level alignment. A 0.2 eV downward band bending together with a 0.1 eV interfacial dipole was found at the pentacene side, whereas there was no band bending found at the CH_3NH_3PbI_3 side. The offset between CH_3NH_3PbI_3 Valance Band Maximum (VBM) and pentacene Highest Occupied Molecular Orbital (HOMO) and that between CH_3NH_3PbI_3 Conduction Band Minimum (CBM) and pentacene Lowest Unoccupied Molecular Orbital (LUMO) was determined to be 0.7 and 1.35 eV, respectively. The band alignment at this interface is favor of efficient hole transfer, which suggests pentacene as a viable HTL candidate to be explored in perovskite solar cells.

  7. 41 CFR 102-117.255 - What actions may I take if the TSP's performance is not satisfactory?

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What actions may I take if the TSP's performance is not satisfactory? 102-117.255 Section 102-117.255 Public Contracts and... may I take if the TSP's performance is not satisfactory? If the TSP's performance is not satisfactory...

  8. Herschel/HIFI deepens the circumstellar NH3 enigma

    NARCIS (Netherlands)

    Menten, K. M.; Wyrowski, F.; Alcolea, J.; De Beck, E.; Decin, L.; Marston, A. P.; Bujarrabal, V.; Cernicharo, J.; Dominik, C.; Justtanont, K.; de Koter, A.; Melnick, G.; Neufeld, D. A.; Olofsson, H.; Planesas, P.; Schmidt, M.; Schoier, F. L.; Szczerba, R.; Teyssier, D.; Waters, L. B. F. M.; Edwards, K.; Olberg, M.; Phillips, T. G.; Morris, P.; Salez, M.; Caux, E.

    2010-01-01

    Context. Circumstellar envelopes (CSEs) of a variety of evolved stars have been found to contain ammonia (NH3) in amounts that exceed predictions from conventional chemical models by many orders of magnitude. Aims. The observations reported here were performed in order to better constrain the NH3

  9. Characteristic of total suspended particulate (TSP) containing Pb and Zn at solid waste landfill

    Science.gov (United States)

    Budihardjo, M. A.; Noveandra, K.; Samadikun, B. P.

    2018-05-01

    Activities conducted at municipal solid waste landfills (MSWLs) potentially cause air pollution. Heavy vehicles in MSWLs release various pollutants that can have negative impacts for humans. One noticeable pollutant at MSWLs is airborne total suspended particulate (TSP) which may contain heavy metals such as Pb and Zn and can cause disease when inhaled by humans. In this study, TSP from a landfill in Semarang, Indonesia was collected and characterized to quantify the concentration of Pb and Zn. Meteorological factors (i.e. temperature, humidity and wind velocity) and landfill activities were considered as factors affecting pollutant concentrations. TSP was sampled using dust samplers while the concentrations of heavy metals in TSP were analyzed using an Atomic Absorption Spectrophotometer (AAS). Pb concentration ranged from 0.84 to 1.78 µg/m3 while Zn concentration was from 7.87 to 8.76 µg/m3. The levels of Pb were below the threshold specified by the Indonesian Government. Meanwhile, the threshold for Zn has not yet been determined.

  10. VOCs emission characteristics and priority control analysis based on VOCs emission inventories and ozone formation potentials in Zhoushan

    Science.gov (United States)

    Wang, Qiaoli; Li, Sujing; Dong, Minli; Li, Wei; Gao, Xiang; Ye, Rongmin; Zhang, Dongxiao

    2018-06-01

    Zhoushan is an island city with booming tourism and service industry, but also has many developed VOCs and/or NOX emission industries. It is necessary to carry out regional VOCs and O3 pollution control in Zhoushan as the only new area owns the provincial economic and social administration rights. Anthropogenic VOCs emission inventories were built based on emission factor method and main emission sources were identified according to the emission inventories. Then, localized VOCs source profiles were built based on in-site sampling and referring to other studies. Furthermore, ozone formation potentials (OFPs) profiles were built through VOCs source profiles and maximum incremental reactivity (MIR) theory. At last, the priority control analysis results showed that industrial processes, especially surface coating, are the key of VOCs and O3 control. Alkanes were the most emitted group, accounting for 58.67%, while aromatics contributed the most to ozone production accounting for 69.97% in total OFPs. n-butane, m/p-xylene, i-pentane, n-decane, toluene, propane, n-undecane, o-xylene, methyl cyclohexane and ethyl benzene were the top 10 VOC species that should be preferentially controlled for VOCs emission control. However, m/p-xylene, o-xylene, ethylene, n-butane, toluene, propene, 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, ethyl benzene and 1,2,3-trimethyl benzene were the top 10 VOC species that required preferential control for O3 pollution control.

  11. Mesoscopic CH 3 NH 3 PbI 3 /TiO 2 Heterojunction Solar Cells

    KAUST Repository

    Etgar, Lioz

    2012-10-24

    We report for the first time on a hole conductor-free mesoscopic methylammonium lead iodide (CH 3NH 3PbI 3) perovskite/TiO 2 heterojunction solar cell, produced by deposition of perovskite nanoparticles from a solution of CH 3NH 3I and PbI 2 in γ-butyrolactone on a 400 nm thick film of TiO 2 (anatase) nanosheets exposing (001) facets. A gold film was evaporated on top of the CH 3NH 3PbI 3 as a back contact. Importantly, the CH 3NH 3PbI 3 nanoparticles assume here simultaneously the roles of both light harvester and hole conductor, rendering superfluous the use of an additional hole transporting material. The simple mesoscopic CH 3NH 3PbI 3/TiO 2 heterojunction solar cell shows impressive photovoltaic performance, with short-circuit photocurrent J sc= 16.1 mA/cm 2, open-circuit photovoltage V oc = 0.631 V, and a fill factor FF = 0.57, corresponding to a light to electric power conversion efficiency (PCE) of 5.5% under standard AM 1.5 solar light of 1000 W/m 2 intensity. At a lower light intensity of 100W/m 2, a PCE of 7.3% was measured. The advent of such simple solution-processed mesoscopic heterojunction solar cells paves the way to realize low-cost, high-efficiency solar cells. © 2012 American Chemical Society.

  12. Degradation mechanism of CH3NH3PbI3 perovskite materials upon exposure to humid air

    International Nuclear Information System (INIS)

    Shirayama, Masaki; Kato, Masato; Fujiseki, Takemasa; Hara, Shota; Kadowaki, Hideyuki; Murata, Daisuke; Fujiwara, Hiroyuki; Miyadera, Tetsuhiko; Sugita, Takeshi; Chikamatsu, Masayuki

    2016-01-01

    Low stability of organic-inorganic perovskite (CH 3 NH 3 PbI 3 ) solar cells in humid air environments is a serious drawback which could limit practical application of this material severely. In this study, from real-time spectroscopic ellipsometry characterization, the degradation mechanism of ultra-smooth CH 3 NH 3 PbI 3 layers prepared by a laser evaporation technique is studied. We present evidence that the CH 3 NH 3 PbI 3 degradation in humid air proceeds by two competing reactions of (i) the PbI 2 formation by the desorption of CH 3 NH 3 I species and (ii) the generation of a CH 3 NH 3 PbI 3 hydrate phase by H 2 O incorporation. In particular, rapid phase change occurs in the near-surface region and the CH 3 NH 3 PbI 3 layer thickness reduces rapidly in the initial 1 h air exposure even at a low relative humidity of 40%. After the prolonged air exposure, the CH 3 NH 3 PbI 3 layer is converted completely to hexagonal platelet PbI 2 /hydrate crystals that have a distinct atomic-scale multilayer structure with a period of 0.65 ± 0.05 nm. We find that conventional x-ray diffraction and optical characterization in the visible region, used commonly in earlier works, are quite insensitive to the surface phase change. Based on results obtained in this work, we discuss the degradation mechanism of CH 3 NH 3 PbI 3 in humid air.

  13. Probing interfacial electronic properties of graphene/CH3NH3PbI3 heterojunctions: A theoretical study

    Science.gov (United States)

    Hu, Jisong; Ji, Gepeng; Ma, Xinguo; He, Hua; Huang, Chuyun

    2018-05-01

    Interfacial interactions and electronic properties of graphene/CH3NH3PbI3 heterojunctions were investigated by first-principles calculations incorporating semiempirical dispersion-correction scheme to describe van der Waals interactions. Two lattice match configurations between graphene and CH3NH3PbI3(0 0 1) slab were constructed in parallel contact and both of them were verified to form remarkable van der Waals heterojunctions with similar work functions. Our calculated energy band structures show that the Dirac-cone of graphene and the direct band gap of CH3NH3PbI3 are still preserved in the heterojunctions, thus graphene can be a promising candidate either as a capping or supporting layer for encapsulating CH3NH3PbI3 layer. It is identified that the Schottky barrier of graphene/CH3NH3PbI3 heterojunctions can be controlled by the interlayer distance and affected by the stacking pattern of graphene and CH3NH3PbI3. The 3D charge density differences present the build-in internal electric field from graphene to CH3NH3PbI3 after interface equilibrium and thus, a low n-type Schottky barrier is needed for high efficient charge transferring in the interface. The possible mechanism of the band edge modulations in the heterojunctions and corresponding photoinduced charge transfer processes are also described.

  14. NH{sub 4}-doped anodic WO{sub 3} prepared through anodization and subsequent NH{sub 4}OH treatment for water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-Wook; Kim, Sunkyu; Seong, Mijeong; Yoo, Hyeonseok; Choi, Jinsub, E-mail: jinsub@inha.ac.kr

    2015-01-01

    Highlights: • NN{sub 4}-doped WO{sub 3} was successfully fabricated by a wet-based method using ammonium hydroxide (NH{sub 4}OH). • (NH{sub 4}){sub 10}W{sub 12}O{sub 41} phase was formed during the NH{sub 4}OH treatment. • Over-doped NH{sub 4} in WO{sub 3} led to reduced photo-electrochemical performance for OER. • The optimized surface was achieved by thermal treatment of anodic WO{sub 3} with 2 g of NH{sub 4}OH solution. - Abstract: Tungsten trioxide (WO{sub 3}) prepared by anodization of a W foil was doped with NH{sub 4} through NH{sub 4}OH treatment at 450 °C. Since aqueous NH{sub 4}OH was used during doping instead of NH{sub 3} gas, the treatment step does not require complicated annealing facilities. Moreover, the state of doped N is a form of NH{sub 3}-W instead of W{sub 2}N, which lowers the bandgap but increases photocorrosion. We found that incorporation of NH{sub 4} into WO{sub 3} leads to reduction of the bandgap from 2.9 eV to 2.2 eV, regardless of the amount of NH{sub 4}OH treatment, lowering the onset potential and increasing the current density at fixed potential for oxygen evolution reaction under illumination. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were employed to investigate the surface morphologies, crystallinities of tungsten oxides and existence of NH{sub 4} doping, respectively. The bandgap energy was determined by UV–Vis spectroscopy to measure the transmittance and refraction. The water splitting performance of each sample was measured by electrochemical linear sweep voltammetry in a 3-electrode configuration under illumination.

  15. Mixed adenine/guanine quartets with three trans-a2 Pt(II) (a=NH(3) or MeNH(2)) cross-links: linkage and rotational isomerism, base pairing, and loss of NH(3).

    Science.gov (United States)

    Albertí, Francisca M; Rodríguez-Santiago, Luis; Sodupe, Mariona; Mirats, Andrea; Kaitsiotou, Helena; Sanz Miguel, Pablo J; Lippert, Bernhard

    2014-03-17

    Of the numerous ways in which two adenine and two guanines (N9 positions blocked in each) can be cross-linked by three linear metal moieties such as trans-a2 Pt(II) (with a=NH3 or MeNH2 ) to produce open metalated purine quartets with exclusive metal coordination through N1 and N7 sites, one linkage isomer was studied in detail. The isomer trans,trans,trans-[{Pt(NH3 )2 (N7-9-EtA-N1)2 }{Pt(MeNH2 )2 (N7-9-MeGH)}2 ][(ClO4 )6 ]⋅3H2 O (1) (with 9-EtA=9-ethyladenine and 9-MeGH=9-methylguanine) was crystallized from water and found to adopt a flat Z-shape in the solid state as far as the trinuclear cation is concerned. In the presence of excess 9-MeGH, a meander-like construct, trans,trans,trans-[{Pt(NH3 )2 (N7-9-EtA-N1)2 }{Pt(MeNH2 )2 (N7-9-MeGH)2 }][(ClO4 )6 ]⋅[(9-MeGH)2 ]⋅7 H2 O (2) is formed, in which the two extra 9-MeGH nucleobases are hydrogen bonded to the two terminal platinated guanine ligands of 1. Compound 1, and likewise the analogous complex 1 a (with NH3 ligands only), undergo loss of an ammonia ligand and formation of NH4 (+) when dissolved in [D6 ]DMSO. From the analogy between the behavior of 1 and 1 a it is concluded that a NH3 ligand from the central Pt atom is lost. Addition of 1-methylcytosine (1-MeC) to such a DMSO solution reveals coordination of 1-MeC to the central Pt. In an analogous manner, 9-MeGH can coordinate to the central Pt in [D6 ]DMSO. It is proposed that the proton responsible for formation of NH4 (+) is from one of the exocyclic amino groups of the two adenine bases, and furthermore, that this process is accompanied by a conformational change of the cation from Z-form to U-form. DFT calculations confirm the proposed mechanism and shed light on possible pathways of this process. Calculations show that rotational isomerism is not kinetically hindered and that it would preferably occur previous to the displacement of NH3 by DMSO. This displacement is the most energetically costly step, but it is compensated by the proton

  16. Effects of atmospheric ammonia (NH3) on terrestrial vegetation: a review

    International Nuclear Information System (INIS)

    Krupa, S.V.

    2003-01-01

    A review of atmospheric ammonia (NH 3 ) and ammonium (NH 4 + ) deposition and their effects on plants. - At the global scale, among all N (nitrogen) species in the atmosphere and their deposition on to terrestrial vegetation and other receptors, NH 3 (ammonia) is considered to be the foremost. The major sources for atmospheric NH 3 are agricultural activities and animal feedlot operations, followed by biomass burning (including forest fires) and to a lesser extent fossil fuel combustion. Close to its sources, acute exposures to NH 3 can result in visible foliar injury on vegetation. NH 3 is deposited rapidly within the first 4-5 km from its source. However, NH 3 is also converted in the atmosphere to fine particle NH 4 + (ammonium) aerosols that are a regional scale problem. Much of our current knowledge of the effects of NH 3 on higher plants is predominantly derived from studies conducted in Europe. Adverse effects on vegetation occur when the rate of foliar uptake of NH 3 is greater than the rate and capacity for in vivo detoxification by the plants. Most to least sensitive plant species to NH 3 are native vegetation > forests > agricultural crops. There are also a number of studies on N deposition and lichens, mosses and green algae. Direct cause and effect relationships in most of those cases (exceptions being those locations very close to point sources) are confounded by other environmental factors, particularly changes in the ambient SO 2 (sulfur dioxide) concentrations. In addition to direct foliar injury, adverse effects of NH 3 on higher plants include alterations in: growth and productivity, tissue content of nutrients and toxic elements, drought and frost tolerance, responses to insect pests and disease causing microorganisms (pathogens), development of beneficial root symbiotic or mycorrhizal associations and inter species competition or biodiversity. In all these cases, the joint effects of NH 3 with other air pollutants such as all-pervasive O 3 or

  17. Incorporation Between AHP and N-TSP for Plant Surveillance Routing with Multiple Constraints

    International Nuclear Information System (INIS)

    Djoko Hari Nugroho

    2002-01-01

    This paper observed plant on-line surveillance routing for maintenance management with multiple constraints using TSP (Traveling Salesman Problem). In the research N-TSP (nomadic TSP) type was used. In this case, on-line surveillance could be implemented on moving robot. Route for preventive maintenance management was observed sequentially per stage using multiple constraints (a) distance between components, and (b) failure probability of components using AHP (Analytical Hierarchy Process). Simulation was observed utilizing DURESS as a complex system. The simulation result showed that the route with single constraint distance between components represents the sequence of 1 - 6 - 2 - 4 - 3 - 5. Routing for DURESS with multiple constraints using incorporation of AHP and TSP showed that the first priority in the route is flow sensor FB2 with the value of comparation of 0.1042. The next priority is sequentially FB1, FA2, FA1, FA, FB, VB, VA, VA1, VA2, VB1, VB2, pump B, pump A, FR1, FR2, reservoir 2, and reservoir 1. Numerical experiment obtained that the incorporation between AHP and N-TSP has successfully constructed the surveillance routing with multiple constraints. (author)

  18. Heterogeneous reactions between ions NH3+and NH+andhydrocarbons adsorbed on a tungsten surface.Formation of HCN+in NH+-surface hydrocarbon collisions

    Czech Academy of Sciences Publication Activity Database

    Harnisch, M.; Scheier, P.; Herman, Zdeněk

    2015-01-01

    Roč. 392, DEC 2015 (2015), s. 139-144 ISSN 1387-3806 Institutional support: RVO:61388955 Keywords : ion-surface collisions * NH3+ and NH+projectiles * surface hydrocarbons Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.183, year: 2015

  19. Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition

    Science.gov (United States)

    Chao, Li-Min; Tai, Ting-Yu; Chen, Yueh-Ying; Lin, Pei-Ying; Fu, Yaw-Shyan

    2015-01-01

    In our study, one-dimensional PbI2/polyvinylpyrrolidone (PVP) composition fibers have been prepared by using PbI2 and PVP as precursors dissolved in N,N-dimethylformamide via a electrospinning process. Dipping the fibers into CH3NH3I solution changed its color, indicating the formation of CH3NH3PbI3, to obtain CH3NH3PbI3/PVP composite fibers. The structure, morphology and composition of the all as-prepared fibers were characterized by using X-ray diffraction and scanning electron microscopy. PMID:28793517

  20. Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition

    Directory of Open Access Journals (Sweden)

    Li-Min Chao

    2015-08-01

    Full Text Available In our study, one-dimensional PbI2/polyvinylpyrrolidone (PVP composition fibers have been prepared by using PbI2 and PVP as precursors dissolved in N,N-dimethylformamide via a electrospinning process. Dipping the fibers into CH3NH3I solution changed its color, indicating the formation of CH3NH3PbI3, to obtain CH3NH3PbI3/PVP composite fibers. The structure, morphology and composition of the all as-prepared fibers were characterized by using X-ray diffraction and scanning electron microscopy.

  1. Effects of atmospheric ammonia (NH3) on terrestrial vegetation: a review.

    Science.gov (United States)

    Krupa, S V

    2003-01-01

    At the global scale, among all N (nitrogen) species in the atmosphere and their deposition on to terrestrial vegetation and other receptors, NH3 (ammonia) is considered to be the foremost. The major sources for atmospheric NH3 are agricultural activities and animal feedlot operations, followed by biomass burning (including forest fires) and to a lesser extent fossil fuel combustion. Close to its sources, acute exposures to NH3 can result in visible foliar injury on vegetation. NH3 is deposited rapidly within the first 4-5 km from its source. However, NH3 is also converted in the atmosphere to fine particle NH4+ (ammonium) aerosols that are a regional scale problem. Much of our current knowledge of the effects of NH3 on higher plants is predominantly derived from studies conducted in Europe. Adverse effects on vegetation occur when the rate of foliar uptake of NH3 is greater than the rate and capacity for in vivo detoxification by the plants. Most to least sensitive plant species to NH3 are native vegetation > forests > agricultural crops. There are also a number of studies on N deposition and lichens, mosses and green algae. Direct cause and effect relationships in most of those cases (exceptions being those locations very close to point sources) are confounded by other environmental factors, particularly changes in the ambient SO2 (sulfur dioxide) concentrations. In addition to direct foliar injury, adverse effects of NH3 on higher plants include alterations in: growth and productivity, tissue content of nutrients and toxic elements, drought and frost tolerance, responses to insect pests and disease causing microorganisms (pathogens), development of beneficial root symbiotic or mycorrhizal associations and inter species competition or biodiversity. In all these cases, the joint effects of NH3 with other air pollutants such as all-pervasive O3 or increasing CO2 concentrations are poorly understood. While NH3 uptake in higher plants occurs through the shoots, NH4

  2. 13N-NH3 PET in the diagnosis of astrocytomas: preliminary result

    International Nuclear Information System (INIS)

    Zhang Xiangsong; He Zuoxiang; Tang Anwu

    2004-01-01

    Objective: To evaluate the feasibility of diagnosing the astrocytoma with 13N-NH3 PET imaging. Methods 13N-NH3 and 18F-fluorodeoxyglucose (FDG) PET imaging were performed in seven cases of astrocytomas including 3 anteoperative astrocytomas, 2 recurrent astrocytomas, 2 brain injury or necrosis after the operation and radiotherapy. The radioactivity ratios of the tumor and normal white matter (T/WM) were calculated. Results: The tumor lesions in 3 anteoperative astrocytomas and 2 recurrent astrocytomas all uptake 13N-NH3. The average T/WM on 13N-NH3 images was 1.82±0.21, and T/WM on 13N-NH3 and 18F-FDG images were 1.98 and 0.97 for one case with grade 1 astrocytoma. 13N-NH3 and 18F-FDG PET imaging both showed decreased uptake in 2 brain injury or necrosis after the operation and radiotherapy of astrocytomas. Conclusions: 13N-NH3 was uptaken in astrocytomas. 13N-NH3 can be useful in the diagnosis of astrocytoma, and potentially improve diagnostic accuracy of astrocytoma, especially in low-grade astrocytoma. (authors)

  3. 13N-NH3 PET in the diagnosis of astrocytomas: preliminary result

    International Nuclear Information System (INIS)

    Zhang Xiangsong; He Zuoxiang; Tang Anwu

    2004-01-01

    Objective: To evaluate the feasibility of diagnosing the astrocytoma with 13N-NH3 PET imaging. Methods: 13N-NH3 and 18F-fluorodeoxyglucose (FDG) PET imaging were performed in seven cases of astrocytomas including 3 anteoperative astrocytomas, 2 recurrent astrocytomas, 2 brain injury or necrosis after the operation and radiotherapy. The radioactivity ratios of the tumor and normal white matter (T/WM) were calculated. Results: The tumor lesions in 3 anteoperative astrocytomas and 2 recurrent astrocytomas all uptake 13N-NH3 .The average T/WM on 13N-NH3 images was 1.82±0.21, and T/WM on 13N-NH3 and 18F-FDG images were 1.98 and 0.97 for one case with grade 1 astrocytoma. 13N-NH3 and 18F-FDG PET imaging both showed decreased uptake in 2 brain injury or necrosis after the operation and radiotherapy of astrocytomas. Conclusions: 13N-NH3 was uptaken in astrocytomas. 13N-NH3 can be useful in the diagnosis of astrocytoma, and potentially improve diagnostic accuracy of astrocytoma, especially in low-grade astrocytoma. (authors)

  4. Process-based modelling of NH3 exchange with grazed grasslands

    Science.gov (United States)

    Móring, Andrea; Vieno, Massimo; Doherty, Ruth M.; Milford, Celia; Nemitz, Eiko; Twigg, Marsailidh M.; Horváth, László; Sutton, Mark A.

    2017-09-01

    In this study the GAG model, a process-based ammonia (NH3) emission model for urine patches, was extended and applied for the field scale. The new model (GAG_field) was tested over two modelling periods, for which micrometeorological NH3 flux data were available. Acknowledging uncertainties in the measurements, the model was able to simulate the main features of the observed fluxes. The temporal evolution of the simulated NH3 exchange flux was found to be dominated by NH3 emission from the urine patches, offset by simultaneous NH3 deposition to areas of the field not affected by urine. The simulations show how NH3 fluxes over a grazed field in a given day can be affected by urine patches deposited several days earlier, linked to the interaction of volatilization processes with soil pH dynamics. Sensitivity analysis showed that GAG_field was more sensitive to soil buffering capacity (β), field capacity (θfc) and permanent wilting point (θpwp) than the patch-scale model. The reason for these different sensitivities is dual. Firstly, the difference originates from the different scales. Secondly, the difference can be explained by the different initial soil pH and physical properties, which determine the maximum volume of urine that can be stored in the NH3 source layer. It was found that in the case of urine patches with a higher initial soil pH and higher initial soil water content, the sensitivity of NH3 exchange to β was stronger. Also, in the case of a higher initial soil water content, NH3 exchange was more sensitive to the changes in θfc and θpwp. The sensitivity analysis showed that the nitrogen content of urine (cN) is associated with high uncertainty in the simulated fluxes. However, model experiments based on cN values randomized from an estimated statistical distribution indicated that this uncertainty is considerably smaller in practice. Finally, GAG_field was tested with a constant soil pH of 7.5. The variation of NH3 fluxes simulated in this way

  5. Molecular beam epitaxy of GaN(0001) utilizing NH3 and/or NH+x ions: Growth kinetics and defect structure

    International Nuclear Information System (INIS)

    Lee, N.; Powell, R.C.; Kim, Y.; Greene, J.E.

    1995-01-01

    Gas-source molecular beam epitaxy (GS-MBE), utilizing Ga and NH 3 , and reactive-ion MBE (RIMBE), incorporating both thermal NH 3 and low-energy NH + x ions, were used to grow single crystal GaN(0001) layers on Al 2 O 3 (0001) at temperatures T s between 700 and 850 degree C with deposition rates of 0.2--0.5 μm h -1 . The RIMBE experiments were carried out with incident NH + x /Ga flux ratios J NH + x /J Ga =1.9--3.2 and NH + x acceleration energies E NH + x =45--90 eV. Plan-view and cross-sectional transmission electron microscopy analyses showed that the primary defects in the GS-MBE films were threading dislocations having either pure edge or mixed edge/screw characteristics with Burgers vectors bar b=1/3 left-angle 2 bar 1 bar 10 right-angle, basal-plane stacking faults with displacement vectors bar R=1/6 left-angle 02 bar 23 right-angle, and prismatic stacking faults with bar R=1/2 left-angle bar 1101 right-angle. In the case of RIMBE films, no stacking faults or residual ion-induced defects were observed with E NH + x =45 eV and T s ≥800 degree C. However, increasing E NH + x to ≥60 eV at T s =800 degree C gave rise to the formation of residual ion-induced point-defect clusters observable by transmission electron microscopy (TEM). Increasing T s to 850 degree C with E NH + x ≥60 eV resulted in the ion-induced defects aggregating to form interstitial basal and prismatic dislocation loops, whose number densities depended upon the ion flux, with Burgers vectors 1/2 left-angle 0001 right-angle and 1/3 left-angle 2 bar 1 bar 10 right-angle, respectively. (Abstract Truncated)

  6. Atmospheric NH3 as plant nutrient: A case study with Brassica oleracea

    International Nuclear Information System (INIS)

    Castro, Ana; Stulen, Ineke; De Kok, Luit J.

    2008-01-01

    Nutrient-sufficient and nitrate- or sulfate-deprived plants of Brassica oleracea L. were exposed to 4 μl l -1 NH 3 (2.8 mg m -3 ), and effects on biomass production and allocation, N-compounds and root morphology investigated. Nitrate-deprived plants were able to transfer to atmospheric NH 3 as nitrogen source, but biomass allocation in favor of the root was not changed by exposure to NH 3 . NH 3 reduced the difference in total root length between nitrate-sufficient and nitrate-deprived plants, and increased the specific root length in the latter. The internal N status, therefore, might be involved in controlling root length in B. oleracea. Root surface area, volume and diameter were unaffected by both nitrate deprivation and NH 3 exposure. In sulfate-deprived plants an inhibitory effect of NH 3 on root morphological parameters was observed. These plants, therefore, might be more susceptible to atmospheric NH 3 than nitrate-deprived plants. The relevance of the present data under field conditions is discussed. - Atmospheric NH 3 can serve as sole N source for Brassica oleracea, but does not change root biomass allocation in nitrate-deprived plants

  7. A review of tsp as one of the transportation security aspects of nuclear materials

    International Nuclear Information System (INIS)

    Wiryono

    2013-01-01

    A review has done for the Transportation Safety Plan (TSP) as one of the aspects of safety in the transport of nuclear materials. The review is necessary to harmonize national regulations with international practice. International practice of using TSP as one of the security requirements in addition to the Radiation Protection Program as a requirement of safety in the transport of nuclear materials. TSP is intended to ensure sound implementation of the transport of nuclear materials. TSP evaluation process can be done with a prescriptive approach, performance, and combinations. TSP contains information about administrative requirements, delivery security and response planning. TSP can be used to ensure the security of the implementation of the transport of nuclear materials effectively and efficiently. BAPETEN should require the applicant to submit the TSP as one document security requirements prior approval transporting nuclear materials. BAPETEN need to define the approach to the formulation and evaluation of TSP. BAPETEN need to set up an evaluation and inspection procedures for the implementation of TSP. (author)

  8. The tumor suppressor PTEN inhibits EGF-induced TSP-1 and TIMP-1 expression in FTC-133 thyroid carcinoma cells

    International Nuclear Information System (INIS)

    Soula-Rothhut, Mahdhia; Coissard, Cyrille; Sartelet, Herve; Boudot, Cedric; Bellon, Georges; Martiny, Laurent; Rothhut, Bernard

    2005-01-01

    Thrombospondin-1 (TSP-1) is a multidomain extracellular macromolecule that was first identified as natural modulator of angiogenesis and tumor growth. In the present study, we found that epidermal growth factor (EGF) up-regulated TSP-1 expression in FTC-133 (primary tumor) but not in FTC-238 (lung metastasis) thyroid cancer cells. Both EGF and TSP-1 induced expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) in a mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) and phosphatidylinositol 3-kinase (PI3-kinase)-dependent manner. In FTC-133 cells, EGF induced proliferation in a TSP-1- and TIMP-1-dependent manner. In addition, we determined that re-expression of the tumor suppressor protein PTEN induced cell death, an effect that correlated with a block of Akt kinase phosphorylation. EGF-induced TSP-1 and TIMP-1 promoter activity and protein expression were inhibited in FTC-133 cells stably expressing wtPTEN but not in cells expressing mutant PTEN. Furthermore, we found that wtPTEN inhibited EGF-but not TSP-1-stimulated FTC-133 cell migration and also inhibited invasion induced by EGF and by TSP-1. Finally, an antibody against TSP-1 reversed EGF-stimulated FTC-133 cell invasion as well as the constitutive invasive potential of FTC-238 cells. Overall, our results suggest that PTEN can function as an important modulator of extracellular matrix proteins in thyroid cancer. Therefore, analyzing differential regulation of TSP-1 by growth factors such as EGF can be helpful in understanding thyroid cancer development

  9. Shape-Evolution Control of hybrid perovskite CH3NH3PbI3 crystals via solvothermal synthesis

    Science.gov (United States)

    Zhang, Baohua; Guo, Fuqiang; Yang, Lianhong; Jia, Xiuling; Liu, Bin; Xie, Zili; Chen, Dunjun; Lu, Hai; Zhang, Rong; Zheng, Youdou

    2017-02-01

    We systematically synthesized CH3NH3PbI3 crystals using solvothermal process, and the reaction conditions such as concentration of the precursor, temperature, time, and lead source have been comprehensively investigated to obtain shape-controlled CH3NH3PbI3 crystals. The results showed that the CH3NH3PbI3 crystals exhibit tetragonal phase and the crystals change from nanoparticles to hopper-faced cuboids. Photoluminescence spectra of the crystals obtained with different lead sources show a blue shift due to the presence of defects in the crystals, and the peak intensity is very sensitive to the lead sources. Moreover, impurities (undesirable byproducts and excess components like HI or CH3NH2) presented during crystal growth can result in hopper growth.

  10. Transparent CH{sub 3}NH{sub 3}SnCl{sub 3}/Al-ZnO p-n heterojunction diode

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sunil, E-mail: skbgudha@gmail.com; Ansari, Mohd Zubair; Khare, Neeraj [Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi, Delhi-110016 (India)

    2016-05-23

    A p-type Organic inorganic tin chloride (CH{sub 3}NH{sub 3}SnCl{sub 3}) perovskite thin film has been synthesized by solution method. An n-type 1% Al doped ZnO (AZO) film has been deposited on FTO substrate by ultrasonic assisted chemical vapor deposition technique. A transparent CH{sub 3}NH{sub 3}SnCl{sub 3}/AZO p-n heterojunction diode has been fabricated by spin coating technique. CH{sub 3}NH{sub 3}SnCl{sub 3}/AZO p-n heterojunction shows 75% transparency in the visible region. I-V characteristic of CH{sub 3}NH{sub 3}SnCl{sub 3}/AZO p-n heterojunction shows rectifying behavior of the diode. The diode parameters calculated as ideality factor η=2.754 and barrier height Φ= 0.76 eV. The result demonstrates the potentiality of CH{sub 3}NH{sub 3}SnCl{sub 3}/AZO p-n heterojunction for transparent electronics.

  11. Urban NH3 levels and sources in six major Spanish cities.

    Science.gov (United States)

    Reche, Cristina; Viana, Mar; Karanasiou, Angeliki; Cusack, Michael; Alastuey, Andrés; Artiñano, Begoña; Revuelta, M Aranzazu; López-Mahía, Purificación; Blanco-Heras, Gustavo; Rodríguez, Sergio; Sánchez de la Campa, Ana M; Fernández-Camacho, Rocío; González-Castanedo, Yolanda; Mantilla, Enrique; Tang, Y Sim; Querol, Xavier

    2015-01-01

    A detailed spatial and temporal assessment of urban NH3 levels and potential emission sources was made with passive samplers in six major Spanish cities (Barcelona, Madrid, A Coruña, Huelva, Santa Cruz de Tenerife and Valencia). Measurements were conducted during two different periods (winter-autumn and spring-summer) in each city. Barcelona showed the clearest spatial pattern, with the highest concentrations in the old city centre, an area characterised by a high population density and a dense urban architecture. The variability in NH3 concentrations did not follow a common seasonal pattern across the different cities. The relationship of urban NH3 with SO2 and NOX allowed concluding on the causes responsible for the variations in NH3 levels between measurement periods observed in Barcelona, Huelva and Madrid. However, the factors governing the variations in A Coruña, Valencia and Santa Cruz de Tenerife are still not fully understood. This study identified a broad variability in NH3 concentrations at the city-scale, and it confirms that NH3 sources in Spanish urban environments are vehicular traffic, biological sources (e.g. garbage containers), wastewater treatment plants, solid waste treatment plants and industry. The importance of NH3 monitoring in urban environments relies on its role as a precursor of secondary inorganic species and therefore PMX. Further research should be addressed in order to establish criteria to develop and implement mitigation strategies for cities, and to include urban NH3 sources in the emission inventories. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. [Ag(NH3)2]Ag(OsO3N)2: a new nitridoosmate(VIII)

    International Nuclear Information System (INIS)

    Wickleder, M.S.; Pley, Martin

    2004-01-01

    Dark brown single crystals of [Ag(NH 3 ) 2 ]Ag(OsO 3 N) 2 were obtained from the reaction of Ag 2 CO 3 , OsO 4 , and NH 3 in aqueous solution. The crystal structure was solved in the monoclinic space group C2/m, with the following unit-cell dimensions: a=1962.5(3), b=633.1(1), c=812.6(1) pm, β=96.71(1) deg. The final reliability factor was R=0.0256 for 1034 reflections with I>2σ(I). Linear [Ag(NH 3 ) 2 ] + ions are present oriented perpendicular to the [010] direction, leading to short Ag + -Ag + distances of 316 pm. A second type of Ag + ions in the crystal structure present coordination number '6+1' and are surrounded by oxygen and nitrogen atoms of the nitridoosmate groups. Within the first of the two crystallographically distinguishable anions one can clearly differentiate between oxygen and nitrogen atoms while the second one exhibits a N/O disorder over two positions. The infrared spectrum of [Ag(NH 3 ) 2 ]Ag(OsO 3 N) 2 shows the typical absorptions which can be attributed to the complex anions and the NH 3 ligands

  13. Crystal Structure Formation of CH3NH3PbI3-xClx Perovskite

    Directory of Open Access Journals (Sweden)

    Shiqiang Luo

    2016-02-01

    Full Text Available Inorganic-organic hydride perovskites bring the hope for fabricating low-cost and large-scale solar cells. At the beginning of the research, two open questions were raised: the hysteresis effect and the role of chloride. The presence of chloride significantly improves the crystallization and charge transfer property of the perovskite. However, though the long held debate over of the existence of chloride in the perovskite seems to have now come to a conclusion, no prior work has been carried out focusing on the role of chloride on the electronic performance and the crystallization of the perovskite. Furthermore, current reports on the crystal structure of the perovskite are rather confusing. This article analyzes the role of chloride in CH3NH3PbI3-xClx on the crystal orientation and provides a new explanation about the (110-oriented growth of CH3NH3PbI3 and CH3NH3PbI3-xClx.

  14. THE KINETICS OF NH(4)+ AND NO3(-) UPTAKE BY DOUGLAS-FIR FROM SINGLE N-SOLUTIONS AND FROM SOLUTIONS CONTAINING BOTH NH(4)+ AND NO3(-)

    NARCIS (Netherlands)

    KAMMINGAVANWIJK, C; PRINS, HBA

    The kinetics of NH4+ and NO3- uptake in young Douglas fir trees (Pseudotsuga menziesii [Mirb.] Franco) were studied in solutions, containing either one or both N species. Using solutions containing a single N species, the V(max) of NH4+ uptake was higher than that of NO3- uptake. The K(m) of NH4+

  15. On approximately fair cost allocation in Euclidean TSP games

    NARCIS (Netherlands)

    Faigle, U.; Fekete, Sándor P.; Hochstättler, Winfried; Kern, Walter

    1998-01-01

    We consider the problem of allocating the cost of an optimal traveling salesman tour in a fair way among the nodes visited; in particular, we focus on the case where the distance matrix of the underlying TSP problem satisfies the triangle inequality. We thereby use the model of TSP games in the

  16. Extraction and Characterization of Tamarind (Tamarind indica L. Seed Polysaccharides (TSP from Three Difference Sources

    Directory of Open Access Journals (Sweden)

    Khanittha Chawananorasest

    2016-06-01

    Full Text Available Tamarind seed polysaccharide (TSP, a natural polysaccharide extracted from tamarind seeds is used in the pharmaceutical, textile and food industries as a mucoadhesive polymer. This work aimed to extract TSP from tamarind seeds from three sources with two methods and characterized its physical and chemical properties. Kernel powder of tamarind seeds was slurried into a clear solution, set aside overnight and then centrifuged at 6000 rpm for 20 min to separate all foreign matter. The supernatant was separated and poured into excess 95% ethanol with continuous stirring. The precipitate obtained was collected and dried in the oven and then the dried TSP polymer was stored in a desiccator. The dried TSP was analyzed by 1H-NMR, FT-IR and XRD. The results showed TSP from tamarind seeds taken from paddy farmland (A, a waste from the export tamarind juice industry (B and the export tamarind powder industry(C gave yields of 31.55%, 26.95% and 17.30%, respectively, using method 1 and 11.15%, 53.65% and 54.65%, with method 2, respectively, but method 2 gave purer TSP than method 1. The FT-IR spectra displayed peaks at 3351.95 cm−1, 2920.76 cm−1, 1018.85 cm−1 and 555.16 cm−1. The 1H-NMR showed polysaccharide peaks between δ 3.50–4.20 ppm and XRD diagrams indicated their amorphous nature. Future works will focus on the quantitative analysis, biological activity and possible use of TSP as a drug delivery system.

  17. [Seasonal variation patterns of NH4(+) -N/NO3(-) -N ratio and delta 15 NH4(+) value in rainwater in Yangtze River Delta].

    Science.gov (United States)

    Xie, Ying-Xin; Zhang, Shu-Li; Zhao, Xu; Xiong, Zheng-Qin; Xing, Guang-Xi

    2008-09-01

    By using a customized manual rainwater sampler made of polyvinyl chloride plastic, the molar ratio of NH4(+) -N/NO3(-) -N and the natural 15N abundance of NH4(+) (delta 15 NH4(+) in rainwater was monitored all year round from June 2003 to July 2005 at three observation sites (Changshu, Nanjing, and Hangzhou) in the Yangtze River Delta. The results indicated that at the three sites, the NH4(+) -N/NO3(-) -N ratio and the delta 15 NH4(+) value in rainwater had the similar seasonal variation trend, being more obvious in Changshu (rural monitoring type) site than in Nanjing (urban monitoring type) and Hangzhou (urban-rural monitoring type) sites. The NH4(+) -N/NO3(-) -N ratio peaked from early June to early August, declined gradually afterwards, and reached the bottom in winter; while the delta 15 NH4(+) value was negative from late June to mid-August, turned positive from late August to mid or late November, became negative again when winter dominated from December to March, but turned positive again in next May and negative again in next July. These seasonal variation patterns of NH4(+) -N/NO3(-) -N ratio and delta 15 NH4(+) value were found in relation to the application of chemical nitrogen fertilizers during different crop growth periods, and also, the alternation of seasons and the NH3 volatilization from other NH3 emission sources (including excrements of human and animals, nitrogen- polluted water bodies, and organic nitrogen sources, etc.), which could be taken as an indicator of defining the sources and form composition of NH4(+) in atmospheric wet deposition and the intensity of various terrestrial NH3 emission sources.

  18. Infrared spectra of the ammonium ion in ammonium metavanadate NH 4VO 3

    Science.gov (United States)

    de Waal, D.; Heyns, A. M.; Range, K.-J.; Eglmeier, C.

    The ND stretching modes of isotopically dilute NH 3D + ions in NH 4VO 3 are in agreement with the predicted splitting into C s, C s and C1(2) components under C s site symmetry for the NH +4 ion. The three bands observed represent the three NH bonding distances in the crystal, and the position, shape and low temperature behaviour of each band confirms the existence of two types of hydrogen bonding in NH 4VO 3. The low temperature infrared modes of NH +4 and ND +4 in NH 4VO 3 and ND 4VO 3, respectively, can be assigned under space group Pbcm. Temperature dependence of these modes also reflects the presence of both normal and bifurcated hydrogen bonds in NH 4VO 3.

  19. Thermodynamic modeling of NH_3-CO_2-SO_2-K_2SO_4-H_2O system for combined CO_2 and SO_2 capture using aqueous NH_3

    International Nuclear Information System (INIS)

    Qi, Guojie; Wang, Shujuan

    2017-01-01

    Highlights: • A new application of aqueous NH_3 based combined CO_2 and SO_2 process was proposed. • A thermodynamic model simulated the heat of absorption and the K_2SO_4 precipitation. • The CO_2 content can be regenerated in a stripper with lower heat of desorption. • The SO_2 content can be removed by K_2SO_4 precipitation from the lean NH_3 solvent. - Abstract: A new application of aqueous NH_3 based post-combustion CO_2 and SO_2 combined capture process was proposed to simultaneously capture CO_2 and SO_2, and remove sulfite by solid (K_2SO_4) precipitation method. The thermodynamic model of the NH_3-CO_2-SO_2-K_2SO_4-H_2O system for the combined CO_2 and SO_2 capture process was developed and validated in this work to analyze the heat of CO_2 and SO_2 absorption in the NH_3-CO_2-SO_2-H_2O system, and the K_2SO_4 precipitation characteristics in the NH_3-CO_2-SO_2-K_2SO_4-H_2O system. The average heat of CO_2 absorption in the NH_3-CO_2-H_2O system at 40 °C is around −73 kJ/mol CO_2 in 2.5 wt% NH_3 with CO_2 loading between 0.2 and 0.5 C/N. The average heat of SO_2 absorption in the NH_3-SO_2-H_2O system at 40 °C is around −120 kJ/mol SO_2 in 2.5 wt% NH_3 with SO_2 loading between 0 and 0.5 S/N. The average heat of CO_2 absorption in the NH_3-CO_2-SO_2-H_2O system at 40 °C is 77, 68, and 58 kJ/mol CO_2 in 2.5 wt% NH_3 with CO_2 loading between 0.2 and 0.5 C/N, when SO_2 loading is 0, 0.1, 0.2 S/N, respectively. The solubility of K_2SO_4 increases with temperature, CO_2 and SO_2 loadings, but decreases with NH_3 concentration in the CO_2 and SO_2 loaded aqueous NH_3. The thermodynamic evaluation indicates that the combined CO_2 and SO_2 capture process could employ the typical absorption/regeneration process to simultaneously capture CO_2 and SO_2 in an absorber, thermally desorb CO_2 in a stripper, and feasibly remove sulfite (oxidized to sulfate) content by precipitating K_2SO_4 from the lean NH_3 solvent after the lean/rich heat exchanger.

  20. Charge carrier localised in zero-dimensional (CH3NH3)3Bi2I9 clusters.

    Science.gov (United States)

    Ni, Chengsheng; Hedley, Gordon; Payne, Julia; Svrcek, Vladimir; McDonald, Calum; Jagadamma, Lethy Krishnan; Edwards, Paul; Martin, Robert; Jain, Gunisha; Carolan, Darragh; Mariotti, Davide; Maguire, Paul; Samuel, Ifor; Irvine, John

    2017-08-01

    A metal-organic hybrid perovskite (CH 3 NH 3 PbI 3 ) with three-dimensional framework of metal-halide octahedra has been reported as a low-cost, solution-processable absorber for a thin-film solar cell with a power-conversion efficiency over 20%. Low-dimensional layered perovskites with metal halide slabs separated by the insulating organic layers are reported to show higher stability, but the efficiencies of the solar cells are limited by the confinement of excitons. In order to explore the confinement and transport of excitons in zero-dimensional metal-organic hybrid materials, a highly orientated film of (CH 3 NH 3 ) 3 Bi 2 I 9 with nanometre-sized core clusters of Bi 2 I 9 3- surrounded by insulating CH 3 NH 3 + was prepared via solution processing. The (CH 3 NH 3 ) 3 Bi 2 I 9 film shows highly anisotropic photoluminescence emission and excitation due to the large proportion of localised excitons coupled with delocalised excitons from intercluster energy transfer. The abrupt increase in photoluminescence quantum yield at excitation energy above twice band gap could indicate a quantum cutting due to the low dimensionality.Understanding the confinement and transport of excitons in low dimensional systems will aid the development of next generation photovoltaics. Via photophysical studies Ni et al. observe 'quantum cutting' in 0D metal-organic hybrid materials based on methylammonium bismuth halide (CH 3 NH 3 )3Bi 2 I 9 .

  1. Towards validation of ammonia (NH3) measurements from the IASI satellite

    Science.gov (United States)

    Van Damme, M.; Clarisse, L.; Dammers, E.; Liu, X.; Nowak, J. B.; Clerbaux, C.; Flechard, C. R.; Galy-Lacaux, C.; Xu, W.; Neuman, J. A.; Tang, Y. S.; Sutton, M. A.; Erisman, J. W.; Coheur, P. F.

    2015-03-01

    Limited availability of ammonia (NH3) observations is currently a barrier for effective monitoring of the nitrogen cycle. It prevents a full understanding of the atmospheric processes in which this trace gas is involved and therefore impedes determining its related budgets. Since the end of 2007, the Infrared Atmospheric Sounding Interferometer (IASI) satellite has been observing NH3 from space at a high spatio-temporal resolution. This valuable data set, already used by models, still needs validation. We present here a first attempt to validate IASI-NH3 measurements using existing independent ground-based and airborne data sets. The yearly distributions reveal similar patterns between ground-based and space-borne observations and highlight the scarcity of local NH3 measurements as well as their spatial heterogeneity and lack of representativity. By comparison with monthly resolved data sets in Europe, China and Africa, we show that IASI-NH3 observations are in fair agreement, but they are characterized by a smaller variation in concentrations. The use of hourly and airborne data sets to compare with IASI individual observations allows investigations of the impact of averaging as well as the representativity of independent observations for the satellite footprint. The importance of considering the latter and the added value of densely located airborne measurements at various altitudes to validate IASI-NH3 columns are discussed. Perspectives and guidelines for future validation work on NH3 satellite observations are presented.

  2. A Low Temperature Infrared Study Of Deuterated NH4VO3

    Science.gov (United States)

    de Waal, D.; Heyns, A. M.

    1989-12-01

    The existence of (NH4)2V6016 as an intermediate in the thermal decomposition of NH4V03 to V205 has been confirmed by vibrational spectroscopy, resulting in the following reaction in an open systeml: NH4VO3 1 bar, air, 50-200°C/(1) (NH4)2v6o16 1 bar, air, ca.360°C/(2) V205 The kinetics of reaction (1) was studied by means of Raman spectroscopy, and structural information on NH4V03 and (N114)V60 16 was required to obtain an accurate description of the reaction mechanism2. Information on the site symmetry of an ammonium ion and hydrogen bonding in a crystal can be obtained by considering the infrared spectra of isotopically dilute NH3D+ ions in the lattice at liquid nitrogen temperatures3, especially as the position of hydrogen atoms in (NHO2V6016 could not be determined by X-ray methods.

  3. Effects of atmospheric ammonia (NH{sub 3}) on terrestrial vegetation: a review

    Energy Technology Data Exchange (ETDEWEB)

    Krupa, S.V

    2003-07-01

    A review of atmospheric ammonia (NH{sub 3}) and ammonium (NH{sub 4}{sup +}) deposition and their effects on plants. - At the global scale, among all N (nitrogen) species in the atmosphere and their deposition on to terrestrial vegetation and other receptors, NH{sub 3} (ammonia) is considered to be the foremost. The major sources for atmospheric NH{sub 3} are agricultural activities and animal feedlot operations, followed by biomass burning (including forest fires) and to a lesser extent fossil fuel combustion. Close to its sources, acute exposures to NH{sub 3} can result in visible foliar injury on vegetation. NH{sub 3} is deposited rapidly within the first 4-5 km from its source. However, NH{sub 3} is also converted in the atmosphere to fine particle NH{sub 4}{sup +} (ammonium) aerosols that are a regional scale problem. Much of our current knowledge of the effects of NH{sub 3} on higher plants is predominantly derived from studies conducted in Europe. Adverse effects on vegetation occur when the rate of foliar uptake of NH{sub 3} is greater than the rate and capacity for in vivo detoxification by the plants. Most to least sensitive plant species to NH{sub 3} are native vegetation > forests > agricultural crops. There are also a number of studies on N deposition and lichens, mosses and green algae. Direct cause and effect relationships in most of those cases (exceptions being those locations very close to point sources) are confounded by other environmental factors, particularly changes in the ambient SO{sub 2} (sulfur dioxide) concentrations. In addition to direct foliar injury, adverse effects of NH{sub 3} on higher plants include alterations in: growth and productivity, tissue content of nutrients and toxic elements, drought and frost tolerance, responses to insect pests and disease causing microorganisms (pathogens), development of beneficial root symbiotic or mycorrhizal associations and inter species competition or biodiversity. In all these cases, the joint

  4. Moessbauer study of 57Fe isolated in NH3 and NH3/Xe matrices

    International Nuclear Information System (INIS)

    Saitovitch, E.M.B.; Litterst, F.J.; Micklitz, H.

    1981-01-01

    Moessbauer studies on 57 Fe isolated in solid ammonia and ammonia/xenon mixtures were perfomed at 4.2 K and 77 K. They show clearly that atomic iron reacts only with one ammonia molecule forming FeNH 3 which is stable in an ammonia matrix up to 77 K. In addition a compound is formed which is attributed to an iron (II) hexammine. (Author) [pt

  5. General working principles of CH3NH3PbX3 perovskite solar cells.

    Science.gov (United States)

    Gonzalez-Pedro, Victoria; Juarez-Perez, Emilio J; Arsyad, Waode-Sukmawati; Barea, Eva M; Fabregat-Santiago, Francisco; Mora-Sero, Ivan; Bisquert, Juan

    2014-02-12

    Organometal halide perovskite-based solar cells have recently realized large conversion efficiency over 15% showing great promise for a new large scale cost-competitive photovoltaic technology. Using impedance spectroscopy measurements we are able to separate the physical parameters of carrier transport and recombination in working devices of the two principal morphologies and compositions of perovskite solar cells, viz. compact thin films of CH3NH3PbI(3-x)Clx and CH3NH3PbI3 infiltrated on nanostructured TiO2. The results show nearly identical spectral characteristics indicating a unique photovoltaic operating mechanism that provides long diffusion lengths (1 μm). Carrier conductivity in both devices is closely matched, so that the most significant differences in performance are attributed to recombination rates. These results highlight the central role of the CH3NH3PbX3 semiconductor absorber in carrier collection and provide a new tool for improved optimization of perovskite solar cells. We report for the first time a measurement of the diffusion length in a nanostructured perovskite solar cell.

  6. First principles study of NH3 molecular adsorption on LiH (100) surfaces

    International Nuclear Information System (INIS)

    Lu Xiaoxia; Chen Yuhong; Dong Xiao

    2012-01-01

    The adsorption of NH 3 on LiH (100) crystal surfaces was studied by first principles method. The preferred adsorption sites, adsorption energy, dissociation energy and electronic structure of the LiH (100)/NH 3 systems were calculated separately. It is found that chemical adsorption happened mainly when NH 3 molecules are on the LiH (100) crystal surfaces. When NH 3 is adsorbed on the Li top site, NH 2 is formed on the LiH (100) crystal surfaces after loss of H atom, the calculated adsorption energy, 0.511 eV, belongs to strong chemical adsorption, then the interaction is strongest. The interaction between NH 2 and the neighboring Li, H are ionic. The covalent bonds are formed between N and H atoms in NH 2 . One H 2 molecule is formed by another H atom in NH 3 and H atom from LiH (100) crystal sur- faces. The covalent bonds are formed between H and H atoms in H 2 . (authors)

  7. Evolution of Chemical Composition, Morphology, and Photovoltaic Efficiency of CH 3 NH 3 PbI 3 Perovskite under Ambient Conditions

    KAUST Repository

    Huang, Weixin; Manser, Joseph S.; Kamat, Prashant V.; Ptasinska, Sylwia

    2016-01-01

    © 2015 American Chemical Society. The surface composition and morphology of CH3NH3PbI3 perovskite films stored for several days under ambient conditions were investigated by X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffraction techniques. Chemical analysis revealed the loss of CH3NH3 + and I- species from CH3NH3PbI3 and its subsequent decomposition into lead carbonate, lead hydroxide, and lead oxide. After long-term storage under ambient conditions, morphological analysis revealed the transformation of randomly distributed defects and cracks, initially present in the densely packed crystalline structure, into relatively small grains. In contrast to PbI2 powder, CH3NH3PbI3 exhibited a different degradation trend under ambient conditions. Therefore, we propose a plausible CH3NH3PbI3 decomposition pathway that explains the changes in the chemical composition of CH3NH3PbI3 under ambient conditions. In addition, films stored under such conditions were incorporated into photovoltaic cells, and their performances were examined. The chemical changes in the decomposed films were found to cause a significant decrease in the photovoltaic efficiency of CH3NH3PbI3.

  8. Evolution of Chemical Composition, Morphology, and Photovoltaic Efficiency of CH 3 NH 3 PbI 3 Perovskite under Ambient Conditions

    KAUST Repository

    Huang, Weixin

    2016-01-12

    © 2015 American Chemical Society. The surface composition and morphology of CH3NH3PbI3 perovskite films stored for several days under ambient conditions were investigated by X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffraction techniques. Chemical analysis revealed the loss of CH3NH3 + and I- species from CH3NH3PbI3 and its subsequent decomposition into lead carbonate, lead hydroxide, and lead oxide. After long-term storage under ambient conditions, morphological analysis revealed the transformation of randomly distributed defects and cracks, initially present in the densely packed crystalline structure, into relatively small grains. In contrast to PbI2 powder, CH3NH3PbI3 exhibited a different degradation trend under ambient conditions. Therefore, we propose a plausible CH3NH3PbI3 decomposition pathway that explains the changes in the chemical composition of CH3NH3PbI3 under ambient conditions. In addition, films stored under such conditions were incorporated into photovoltaic cells, and their performances were examined. The chemical changes in the decomposed films were found to cause a significant decrease in the photovoltaic efficiency of CH3NH3PbI3.

  9. Increase in Ice Nucleation Efficiency of Feldspars, Kaolinite and Mica in Dilute NH3 and NH4+-containing Solutions

    Science.gov (United States)

    Kumar, A.; Marcolli, C.; Luo, B.; Krieger, U. K.; Peter, T.

    2017-12-01

    Semivolatile species present in the atmosphere are prone to adhere to mineral dust particle surfaces during long range transport, and could potentially change the particle surface properties and its ice nucleation (IN) efficiency. Immersion freezing experiments were performed with microcline (K-feldspar), known to be highly IN active, suspended in aqueous solutions of ammonia, (NH4)2SO4, NH4HSO4, NH4NO3, NH4Cl, Na2SO4, H2SO4, K2SO4 and KCl to investigate the effect of solutes on the IN efficiency. Freezing of emulsified droplets investigated with a differential scanning calorimeter (DSC) showed that the heterogeneous ice nucleation temperatures deviate from the water activity-based IN theory, describing heterogeneous ice nucleation temperatures as a function of solution water activity by a constant offset with respect to the ice melting point curve (Zobrist et al. 2008). IN temperatures enhanced up to 4.5 K were observed for very dilute NH3 and NH4+-containing solutions while a decrease was observed as the concentration was further increased. For all solutes with cations other than NH4+, the IN efficiency decreased. An increase of the IN efficiency in very dilute NH3 and NH4+-containing solutions followed by a decrease with increasing concentration was also observed for sanidine (K-feldspar) and andesine (Na/Ca-feldspar). This is an important indication towards specific chemical interactions between solutes and the feldspar surface which is not captured by the water activity-based IN theory. A similar trend is present but less pronounced in case of kaolinite and mica, while quartz is barely affected. We hypothesize that the hydrogen bonding of NH3 molecules with surface -OH groups could be the reason for the enhanced freezing temperatures in dilute ammonia and ammonium containing solutions as they could form an ice-like overlayer providing hydrogen bonding groups for ice to nucleate on top of it. This implies to possibilities of enhanced IN efficiency, especially

  10. The energy level alignment at the CH{sub 3}NH{sub 3}PbI{sub 3}/pentacene interface

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Gengwu [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); University of Chinese Academy of Science, Beijing 100049 (China); Zhao, Bin; Song, Fei [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); Zheng, Guanhaojie; Zhang, Xiaonan [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); University of Chinese Academy of Science, Beijing 100049 (China); Shen, Kongchao [Department of Physics, Zhejiang University, Hangzhou 310027 (China); Yang, Yingguo [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); Chen, Shi, E-mail: ChenShi@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore); Gao, Xingyu, E-mail: gaoxingyu@sinap.ac.cn [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China)

    2017-01-30

    Highlights: • The Energy Level Alignment at the CH{sub 3}NH{sub 3}PbI{sub 3}/Pentacene Interface was resolved experimentally. • The downward band bending and the dipole found at the pentacene side would favorably drive holes away from the interface into pentacene. • A ∼0.7 eV offset between pentacene HOMO and CH{sub 3}NH{sub 3}PbI{sub 3} VBM would be in favor of hole transfer whereas a ∼1.35 eV offset between pentacene LUMO and CH{sub 3}NH{sub 3}PbI{sub 3} CBM should efficiently block the unwanted electron transfer from perovskite to pentacene. • Pentacene could be a viable hole transfer material candidate on perovskite to be explored in perovskite devices. - Abstract: Pentacene thin film on CH{sub 3}NH{sub 3}PbI{sub 3} was studied by in-situ X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy to determine their interfacial energy level alignment. A 0.2 eV downward band bending together with a 0.1 eV interfacial dipole was found at the pentacene side, whereas there was no band bending found at the CH{sub 3}NH{sub 3}PbI{sub 3} side. The offset between CH{sub 3}NH{sub 3}PbI{sub 3} Valance Band Maximum (VBM) and pentacene Highest Occupied Molecular Orbital (HOMO) and that between CH{sub 3}NH{sub 3}PbI{sub 3} Conduction Band Minimum (CBM) and pentacene Lowest Unoccupied Molecular Orbital (LUMO) was determined to be 0.7 and 1.35 eV, respectively. The band alignment at this interface is favor of efficient hole transfer, which suggests pentacene as a viable HTL candidate to be explored in perovskite solar cells.

  11. Emission inventory of anthropogenic air pollutants and VOC species in the Yangtze River Delta region, China

    Directory of Open Access Journals (Sweden)

    C. Huang

    2011-05-01

    Full Text Available The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 in the YRD region for the year 2007 are 2392 kt, 2293 kt, 6697 kt, 3116 kt, 1511 kt, 2767 kt, and 459 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77 % to the total ozone formation potential (OFP. The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around Hangzhou Bay. The industrial sources, including power plants other fuel combustion facilities, and non-combustion processes contribute about 97 %, 86 %, 89 %, 91 %, and 69 % of the total SO2, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3 % and 12.4 % of the NOx and VOC emissions, respectively. Regarding OFPs, the chemical industry, domestic use of paint & printing, and gasoline vehicles contribute 38 %, 24 %, and 12 % to the ozone formation in the YRD region.

  12. Study of the structural phase transitions of (CH 3NH 3) 3Sb 2Cl 9 (MACA) and (CH 3NH 3) 3Bi 2Cl 9 (MACB) by infrared spectroscopy

    Science.gov (United States)

    Bator, G.; Jakubas, R.; Malarski, Z.

    1991-06-01

    Infrared spectra of polycrystalline (CH 3NH 3) 3Sb 2Cl 9 and (CH 3NH 3) 3Bi 2Cl 9 have been studied in the temperature range 90-300 K. A systematic temperature dependence study of the internal modes has been carried out. We discuss the effects of the dynamic state of methylammonium (MA) cations on their vibrational spectra. The results show that the dynamics of MA cations in both compounds is similar in higher (about 300 K) and lower temperature (in the vicinity of 100 K) regions. Substantial differences are revealed in the intermediate temperature interval. The results are in good agreement with earlier dielectric, calorimetric and 1H NMR studies.

  13. NO3-/NH4+ proportions affect cadmium bioaccumulation and tolerance of tomato.

    Science.gov (United States)

    Nogueirol, Roberta Corrêa; Monteiro, Francisco Antonio; de Souza Junior, João Cardoso; Azevedo, Ricardo Antunes

    2018-05-01

    With the growth of the world population, cadmium (Cd) concentration in the environment has increased considerably as a result of human activities such as foundry, battery disposal, mining, application of fertilizers containing toxic elements as impurities, and disposal of metal-containing waste. Higher plants uptake N as ammonium (NH 4 + ), nitrate (NO 3 - ), and many other water-soluble compounds such as urea and amino acids, and nourishing plants with N, providing part of it as NH 4 + , is an interesting alternative to the supply of this nutrient in the exclusive form of NO 3 - under Cd toxicity. The objective was to evaluate the influence of NO 3 - /NH 4 + proportions on the development and tolerance of tomato plants grown under the presence of Cd in the culture medium. The experiment was conducted in a completely randomized block design in a 3 × 3 factorial arrangement consisting of three Cd rates (0, 50, and 100 μmol L -1 ) and three NO 3 - /NH 4 + proportions (100/0, 70/30, and 50/50) in the nutrient solution. To this end, we quantified the responses of the antioxidant enzymatic system and productive and functional changes in Solanum lycopersicum var. esculentum (Calabash Rouge). Shoot biomass production decreased with the maximum Cd rate (100 μmol L -1 ) tested in the growth medium, whereas the NO 3 - /NH 4 + proportions and other Cd rates did not significantly influence this variable. The lowest SPAD values were observed at the 100/0 NO 3 - /NH 4 + proportion and in plants exposed to Cd. The largest accumulation of the metal occurred in the shoots at the NO 3 - /NH 4 + proportion of 70/30 and at 100 μmol L -1 Cd and in the roots at 100/0 NO 3 - /NH 4 + and with 50 and 100 μmol L -1 Cd. The concentration and accumulation of NO 3 - were highest at the NO 3 - /NH 4 + proportion of 100/0 in the shoots and at 50/50 NO 3 - /NH 4 + in the roots, whereas for NH 4 + , values were higher as the proportion of N supplied in the form of NH 4 + was

  14. Rotational spectrum of the NH3–He van der Waals complex

    Directory of Open Access Journals (Sweden)

    Surin L.

    2017-01-01

    Full Text Available The interaction between ammonia and helium has attracted considerable interest over many years, partly because of the observation of interstellar ammonia. The rate coefficients of NH3–He scattering are an important ingredient for numerical modeling of astrochemical environments. Another, though quite different application in which the NH3–He interaction can play an important role is the doping of helium clusters with NH3 molecules to perform high-resolution spectroscopy. Such experiments are directed on the detection of non-classical response of molecular rotation in helium clusters addressing fundamental questions related to the microscopic nature of superfluidity. High-resolution spectroscopy on the NH3–He complex is an important tool for increasing our understanding of intermolecular forces between NH3 and He.

  15. Observation of lower defect density in CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cells by admittance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Minlin; Lan, Fei; Tao, Quan; Li, Guangyong, E-mail: gaod@pitt.edu, E-mail: gul6@pitt.edu [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Zhao, Bingxin [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Key Laboratory of Advanced Functional Materials, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Wu, Jiamin; Gao, Di, E-mail: gaod@pitt.edu, E-mail: gul6@pitt.edu [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)

    2016-06-13

    The introduction of Cl into CH{sub 3}NH{sub 3}PbI{sub 3} precursors is reported to enhance the performance of CH{sub 3}NH{sub 3}PbI{sub 3} solar cell, which is attributed to the significantly increased diffusion lengths of carriers in CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cell. It has been assumed but never experimentally approved that the defect density in CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cell should be reduced according to the higher carrier lifetime observed from photoluminescence (PL) measurement. We have fabricated CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cell by adding a small amount of Cl source into CH{sub 3}NH{sub 3}PbI{sub 3} precursor. The performance of CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cell is significantly improved from 15.39% to 18.60%. Results from scanning electron microscopy and X-ray diffraction indicate that the morphologies and crystal structures of CH{sub 3}NH{sub 3}PbI{sub 3} and CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} thin films remain unchanged. Open circuit voltage decay and admittance spectroscopy characterization jointly approve that Cl plays an extremely important role in suppressing the formation of defects in perovskite solar cells.

  16. Wet Mechanochemical Processing of Celestine using (NH42CO3

    Directory of Open Access Journals (Sweden)

    Deniz Bingöl

    2017-06-01

    Full Text Available In this study, traditional (univariate method of processing to the wet mechanochemical treatment were applied to obtain both SrCO3 and (NH42SO4 from celestite (SrSO4-(NH42CO3-H2O mixtures in a planetary ball mill. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis were used to analyze products formed during wet milling. A hydrometallurgical process was carried out to examine milling time, ball to grinding material mass ratio, (NH42CO3 to SrSO4 mole ratio and rotational speed of the mill in a planetary mill. Under optimum conditions, a conversion approaching 100% of SrCO3 was obtained.

  17. Gold(I) Complexes with N-Donor Ligands. 2.(1) Reactions of Ammonium Salts with [Au(acac-kappaC(2))(PR(3))] To Give [Au(NH(3))L](+), [(AuL)(2)(&mgr;(2)-NH(2))](+), [(AuL)(4)(&mgr;(4)-N)](+), or [(AuL)(3)(&mgr;(3)-O)](+). A New and Facile Synthesis of [Au(NH(3))(2)](+) Salts. Crystal Structure of [{AuP(C(6)H(4)OMe-4)(3)}(3)(&mgr;(3)-O)]CF(3)SO(3).

    Science.gov (United States)

    Vicente, José; Chicote, María-Teresa; Guerrero, Rita; Jones, Peter G.; Ramírez De Arellano, M. Carmen

    1997-09-24

    The complexes [Au(acac-kappaC(2))(PR(3))] (acac = acetylacetonate, R = Ph, C(6)H(4)OMe-4) react with (NH(4))ClO(4) to give amminegold(I), [Au(NH(3))(PR(3))]ClO(4), amidogold(I), [(AuPR(3))(2)(&mgr;(2)-NH(2))]ClO(4), or nitridogold(I), [(AuPR(3))(4)(&mgr;(4)-N)]ClO(4), complexes, depending on the reaction conditions. Similarly, [Au(acac-kappaC(2))(PPh(3))] reacts with (NH(3)R')OTf (OTf = CF(3)SO(3)) (1:1) or with [H(3)N(CH(2))(2)NH(2)]OTf (1:1) to give (amine)gold(I) complexes [Au(NH(2)R')(PPh(3))]OTf (R' = Me, C(6)H(4)NO(2)-4) or [(AuPPh(3))(2){&mgr;(2)-H(2)N(CH(2))(2)NH(2)}](OTf)(2), respectively. The ammonium salts (NH(2)R'(2))OTf (R' = Et, Ph) react with [Au(acac-kappaC(2))(PR(3))] (R = Ph, C(6)H(4)OMe-4) (1:2) to give, after hydrolysis, the oxonium salts [(AuPR(3))(3)(&mgr;(3)-O)]OTf (R = Ph, C(6)H(4)OMe-4). When NH(3) is bubbled through a solution of [AuCl(tht)] (tht = tetrahydrothiophene), the complex [Au(NH(3))(2)]Cl precipitates. Addition of [Au(NH(3))(2)]Cl to a solution of AgClO(4) or TlOTf leads to the isolation of [Au(NH(3))(2)]ClO(4) or [Au(NH(3))(2)]OTf, respectively. The crystal structure of [(AuPR(3))(3)(&mgr;(3)-O)]OTf.Me(2)CO (R = C(6)H(4)OMe-4) has been determined: triclinic, space group P&onemacr;, a = 14.884(3) Å, b = 15.828(3) Å, c = 16.061(3) Å, alpha = 83.39(3) degrees, beta = 86.28(3) degrees, gamma = 65.54(3) degrees, R1 (wR2) = 0.0370 (0.0788). The [(AuPR(3))(3)(&mgr;(3)-O)](+) cation shows an essentially trigonal pyramidal array of three gold atoms and one oxygen atom with O-Au-P bond angles of ca. 175 degrees and Au.Au contacts in the range 2.9585(7)-3.0505(14) Å. These cations are linked into centrosymmetric dimers through two short Au.Au [2.9585(7), 3.0919(9) Å] contacts. The gold atoms of the dimer form a six-membered ring with a chair conformation.

  18. An entropy-based improved k-top scoring pairs (TSP) method for ...

    African Journals Online (AJOL)

    DR. NJ TONUKARI

    2012-06-05

    Jun 5, 2012 ... Key words: Cancer classification, gene expression, k-TSP, information entropy, gene selection. INTRODUCTION ..... The 88 kDa precursor protein, progranulin, is also ... TCF3 is in acute myeloid leukemia pathway, so it is.

  19. Pressure induced polymorphism in ammonium azide (NH{sub 4}N{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Medvedev, S.A., E-mail: s.medvedev@mpic.de [Max-Planck-Institute for Chemistry, Postfach 3060, D-55020 Mainz (Germany); Institute fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Eremets, M.I. [Max-Planck-Institute for Chemistry, Postfach 3060, D-55020 Mainz (Germany); Evers, J.; Klapoetke, T.M. [Energetic Materials Research, Ludwig-Maximilian University Munich (LMU), Butenandtstrasse 5-13(D), D-81377 Munich (Germany); Palasyuk, T. [Max-Planck-Institute for Chemistry, Postfach 3060, D-55020 Mainz (Germany); Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Trojan, I.A. [Max-Planck-Institute for Chemistry, Postfach 3060, D-55020 Mainz (Germany)

    2011-07-28

    Graphical abstract: Polymorph phase transition is observed in NH{sub 4}N{sub 3} at {approx}3 GPa by pressure dependent Raman studies. The strength of hydrogen bond appears to be modified at the phase transition as illustrated by dependence of N-H stretching frequency on pressure shown on figure. Highlights: {yields} Ammonium azide (NH{sub 4}N{sub 3}) studied at high pressures by Raman spectroscopy. {yields} Phase transition is observed at pressure {approx}3 GPa. {yields} Strength of hydrogen bond appears to be modified at the phase transition. {yields} NH{sub 4}N{sub 3} remain in molecular form up to pressures above 50 GPa. - Abstract: Pressure-dependent Raman spectroscopy studies reveal polymorph phase transition in simple molecular ionic crystal NH{sub 4}N{sub 3} at pressure {approx}3 GPa unobserved by recent abinitio evolutionary structure searches. Hydrogen bonding is spectroscopically evident in both low- and high-pressure phases. The strength of hydrogen bond appears to be modified at the phase transition: in the low-pressure phase NH{sub 4}N{sub 3} behaves as system with very strong hydrogen bonding whereas changes of spectra with pressure in the high-pressure phase are indicative of weak or medium-strength hydrogen bonds. The high pressure phase is most likely thermodynamically stable at least up to pressure {approx}55 GPa contradicting the abinitio studies predicting transformation of NH{sub 4}N{sub 3} to nonmolecular hydronitrogen solid at 36 GPa.

  20. Characterization, source identification and apportionment of selected metals in TSP in an urban atmosphere.

    Science.gov (United States)

    Shah, Munir H; Shaheen, N; Jaffar, M

    2006-03-01

    To understand the metal distribution characteristics in the atmosphere of urban Islamabad, total suspended particulate (TSP) samples were collected on daily 12 h basis, at Quaid-i-Azam University campus, using high volume sampler. The TSP samples were treated with HNO(3)/HClO(4) based wet digestion method for the quantification of eight selected metals; Fe, Zn, Pb, Mn, Cr, Co, Ni and Cd by FAAS method. The monitoring period ran from June 2001 to January 2002, with a total of 194 samples collected on cellulose filters. Effects of different meteorological conditions such as temperature, relative humidity, wind speed and wind direction on selected metal levels were interpreted by means of multivariate statistical approach. Enhanced metal levels for Fe (930 ng/m(3)), Zn (542 ng/m(3)) and Pb (210 ng/m(3)) were found on the mean scale while Mn, Cr, Co and Ni emerged as minor contributors. Statistical correlation study was also conducted and a strong correlation was observed between Pb-Cr (r=0.611). The relative humidity showed some significant influence on atmospheric metal distribution while other meteorological parameters showed weak relationship with TSP metal levels. Regarding the origin of sources of heavy metals in TSP, the statistical procedure identified three source profiles; automobile emissions, industrial/metallurgical units, and natural soil dust. The metal levels were also compared with those reported for other parts of the world which showed that the metal levels in urban atmosphere of Islamabad are in exceedence than those of European industrial and urban sites while comparable with some Asian sites.

  1. Imaging a multidimensional multichannel potential energy surface: Photodetachment of H{sup −}(NH{sub 3}) and NH{sub 4}{sup −}

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Qichi; Johnson, Christopher J.; Continetti, Robert E., E-mail: hguo@umn.edu, E-mail: rcontinetti@ucsd.edu [Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340 (United States); Song, Hongwei; Guo, Hua, E-mail: hguo@umn.edu, E-mail: rcontinetti@ucsd.edu [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Li, Jun [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China)

    2016-06-28

    Probes of the Born-Oppenheimer potential energy surfaces governing polyatomic molecules often rely on spectroscopy for the bound regions or collision experiments in the continuum. A combined spectroscopic and half-collision approach to image nuclear dynamics in a multidimensional and multichannel system is reported here. The Rydberg radical NH{sub 4} and the double Rydberg anion NH{sub 4}{sup −} represent a polyatomic system for benchmarking electronic structure and nine-dimensional quantum dynamics calculations. Photodetachment of the H{sup −}(NH{sub 3}) ion-dipole complex and the NH{sub 4}{sup −} DRA probes different regions on the neutral NH{sub 4} PES. Photoelectron energy and angular distributions at photon energies of 1.17, 1.60, and 2.33 eV compare well with quantum dynamics. Photoelectron-photofragment coincidence experiments indicate dissociation of the nascent NH{sub 4} Rydberg radical occurs to H + NH{sub 3} with a peak kinetic energy of 0.13 eV, showing the ground state of NH{sub 4} to be unstable, decaying by tunneling-induced dissociation on a time scale beyond the present scope of multidimensional quantum dynamics.

  2. Optical constants of CH3NH3PbBr3 perovskite thin films measured by spectroscopic ellipsometry

    KAUST Repository

    Alias, Mohd Sharizal

    2016-07-14

    The lack of optical constants information for hybrid perovskite of CH3NH3PbBr3 in thin films form can delay the progress of efficient LED or laser demonstration. Here, we report on the optical constants (complex refractive index and dielectric function) of CH3NH3PbBr3 perovskite thin films using spectroscopic ellipsometry. Due to the existence of voids, the refractive index of the thin films is around 8% less than the single crystals counterpart. The energy bandgap is around 2.309 eV as obtained from photoluminescence and spectrophotometry spectra, and calculated from the SE analysis. The precise measurement of optical constants will be useful in designing optical devices using CH3NH3PbBr3 thin films.

  3. Degradation mechanism of CH{sub 3}NH{sub 3}PbI{sub 3} perovskite materials upon exposure to humid air

    Energy Technology Data Exchange (ETDEWEB)

    Shirayama, Masaki; Kato, Masato; Fujiseki, Takemasa; Hara, Shota; Kadowaki, Hideyuki; Murata, Daisuke; Fujiwara, Hiroyuki, E-mail: fujiwara@gifu-u.ac.jp [Department of Electrical, Electronic and Computer Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan); Miyadera, Tetsuhiko; Sugita, Takeshi; Chikamatsu, Masayuki [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8568 (Japan)

    2016-03-21

    Low stability of organic-inorganic perovskite (CH{sub 3}NH{sub 3}PbI{sub 3}) solar cells in humid air environments is a serious drawback which could limit practical application of this material severely. In this study, from real-time spectroscopic ellipsometry characterization, the degradation mechanism of ultra-smooth CH{sub 3}NH{sub 3}PbI{sub 3} layers prepared by a laser evaporation technique is studied. We present evidence that the CH{sub 3}NH{sub 3}PbI{sub 3} degradation in humid air proceeds by two competing reactions of (i) the PbI{sub 2} formation by the desorption of CH{sub 3}NH{sub 3}I species and (ii) the generation of a CH{sub 3}NH{sub 3}PbI{sub 3} hydrate phase by H{sub 2}O incorporation. In particular, rapid phase change occurs in the near-surface region and the CH{sub 3}NH{sub 3}PbI{sub 3} layer thickness reduces rapidly in the initial 1 h air exposure even at a low relative humidity of 40%. After the prolonged air exposure, the CH{sub 3}NH{sub 3}PbI{sub 3} layer is converted completely to hexagonal platelet PbI{sub 2}/hydrate crystals that have a distinct atomic-scale multilayer structure with a period of 0.65 ± 0.05 nm. We find that conventional x-ray diffraction and optical characterization in the visible region, used commonly in earlier works, are quite insensitive to the surface phase change. Based on results obtained in this work, we discuss the degradation mechanism of CH{sub 3}NH{sub 3}PbI{sub 3} in humid air.

  4. LPG and NH3 sensing characteristics of DC electrochemically deposited Co3O4 films

    Science.gov (United States)

    Shelke, P. N.; Khollam, Y. B.; Gunjal, S. D.; Koinkar, P. M.; Jadkar, S. R.; Mohite, K. C.

    2015-03-01

    Present communication reports the LPG and NH3 sensing properties of Co3O4 films prepared on throughly cleaned stainless steel (SS) and copper (CU) substrates by using DC electrochemical deposition method followed by air annealing at 350°C/2 h. The resultant films are characterized by using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The LPG and NH3 gas sensing properties of these films are measured at room temperature (RT) by using static gas sensing system at different concentrations of test gas ranging from 25 ppm to 350 ppm. The XRD and Raman spectroscopy studies clearly indicated the formation of pure cubic spinel Co3O4 in all films. The LPG and NH3 gas sensing properties of films showed (i) the increase in sensitivity factor (S.F.) with gas concentrations and (ii) more sensibility to LPG as compared to NH3 gas. In case of NH3 gas (conc. 150 ppm) and LPG gas (conc. 60 ppm) sensing, the maximum S.F. = 270 and 258 are found for the films deposited on CU substrates, respectively. For all films, the response time (3-5 min.) is found to be much higher than the recovery time (30-50 sec). For all films, the response and recovery time are found to be higher for LPG as compared to NH3 gas. Further, repeatability-reproducibility in gas sensing properties is clearly noted by analysis of data for number of cycles recorded for all films from different set of depositions.

  5. Fractionation of applied 32P labeled TSP in calcareous soils

    International Nuclear Information System (INIS)

    Asfary, A.F.; Al-Merey, R.; Al-Hameish, M.

    2005-01-01

    Calcareous dark brown red soil (calcixerollic xerochrept) from northern Syria was used in a pot experiment to study the fate of triple super phosphate fertilizer (TSP) with and without a crop (Local durum wheat (Triticum turgidum L. group durum (Desf)) c v. Bohouth). The soil received 17μg P/g soil of 32 P labeled TSP, and samples were collected from soils and plants at successive dates. Soil inorganic P was ≅94% of total soil P, with only 50-80% being soluble. Calcium phosphate compounds were the dominant fraction (≤68%) of the soluble inorganic soil P followed by occluded iron phosphate (≤48%) and all other fractions were ≤9%. Isotopic measurements showed that ≅ 50% of fertilizer P was nonexchangeable within 2 days, and TSP values in each fraction of soil inorganic P fluctuated in relatively similar proportions to the concentrations of fractions in soil. Available P (soil and TSP) in cropped soil was more than that in the uncropped soil, and plants had no effect on the distribution of P from fertilizer amongst the different P fractions. (author)

  6. Synthesis, characterization, and application of Zn(NH 3)(CO3) for selective adsorptive separation of CO2

    Science.gov (United States)

    Khazeni, Naasser

    This study explores the potential of Zn(NH3)(CO3) for selective CO2 separation. It develops a novel, highly controllable, single-pot synthesis approach based on urea hydrolysis and solvothermal aging to increase the feasibility of synthesizing Zn(NH3)(CO3), determines the structure of Zn(NH3)(CO3) in detail through single crystal X-ray diffraction and powder X-ray diffraction analyses, and performs adsorption analyses for the compound using CO2, N 2, H2, O2, and CH4 as adsorptives. Through adsorptive characterization, a systematic adsorbent selection screening is performed to assess the potential application of Zn(NH3)(CO 3) for adsorptive separation of CO2 from an upstream gas mixture of power generation, hydrogen production, and natural gas industries. Structural analysis shows Zn(NH3)(CO3) to have an inorganic helical framework that consists of a small helix of (ZnOCO) 2 and a large helix of (ZnOCO)4 with two ammines (NH 3) pendant from every other zinc. In terms of adsorption capacity and CO2 selectivity, Zn(NH3)(CO3) adsorbed 0.550 mmole/g CO2 at 293 K and 4500 mmHg, but only 0.047 mmole/g N 2, 0.084 mmole/g H2, 0.207 mmole/g 02, and 0.060 mmole/g CH4 at the same temperature and pressure. This behavior demonstrates considerable equilibrium selectivities - 36, 31, 63, and 11 - for separating CO2 from CH4, CO2 from H 2, CO2 from N2, and CO2 from 02, respectively. During adsorption, the pendant ammines act as the gates of check-valves: applied pressure opens the gates for adsorption; and during desorption, the gates are closed, trapping the adsorbates, until a reduction of pressure to near-atmospheric levels. Therefore, Zn(NH3)(CO3) exhibits low-pressure H3 or H4 hysteresis, indicating that the Zn(NH3)(CO3) framework can achieve gas storage at near-atmospheric pressures. Additionally, the compound proves structurally stable, with an adsorption decrease of 0.8% after 20 adsorption/desorption cycles - a factor that, considered with the other characteristics of Zn(NH

  7. Photovoltaic performance and the energy landscape of CH3NH3PbI3.

    Science.gov (United States)

    Zhou, Yecheng; Huang, Fuzhi; Cheng, Yi-Bing; Gray-Weale, Angus

    2015-09-21

    Photovoltaic cells with absorbing layers of certain perovskites have power conversion efficiencies up to 20%. Among these materials, CH3NH3PbI3 is widely used. Here we use density-functional theory to calculate the energies and rotational energy barriers of a methylammonium ion in the α or β phase of CH3NH3PbI3 with differently oriented neighbouring methylammonium ions. Our results suggest the methylammonium ions in CH3NH3PbI3 prefer to rotate collectively, and to be parallel to their neighbours. Changes in polarization on rotation of methylammonium ions are two to three times larger than those on relaxation of the lead ion from the centre of its coordination shell. The preferences for parallel configuration and concerted rotation, with the polarisation changes, are consistent with ferroelectricity in the material, and indicate that this polarisation is governed by methylammonium orientational correlations. We show that the field due to this polarisation is strong enough to screen the field hindering charge transport, and find this screening field in agreement with experiment. We examine two possible mechanisms for the effect of methylammonium ion rotation on photovoltaic performance. One is that rearrangement of methylammoniums promotes the creation and transport of charge carriers. Some effective masses change greatly, but changes in band structure with methylammonium rotation are not large enough to explain current-voltage hysteresis behaviour. The second possible mechanism is that polarization screens the hindering electric field, which arises from charge accumulation in the transport layers. Polarization changes on methylammonium rotation favour this second mechanism, suggesting that collective reorientation of methylammonium ions in the bulk crystal are in significant part responsible for the hysteresis and power conversion characteristics of CH3NH3PbI3 photovoltaic cells.

  8. Ba2+ Doped CH3NH3PbI3 to Tune the Energy State and Improve the Performance of Perovskite Solar Cells

    International Nuclear Information System (INIS)

    Zhang, Hanbing; Shang, Ming-hui; Zheng, Xiaoying; Zeng, Zhaobing; Chen, Renjie; Zhang, Ying; Zhang, Jing; Zhu, Yuejin

    2017-01-01

    Highlights: •Ba doping enlarges the energy band gap of MAPb 1-x Ba x I 3 . •Voc and Jsc are enhanced in perovskite solar cells. •DFT calculation proves the experiment results. -- Abstract: Elements substitution and doping in perovskite CH 3 NH 3 PbI 3 exhibit versatile tunability of energy band structure and opto-electric properties. Ba 2+ is chosen to substitute Pb 2+ for its similar valence state and ionic radius with Pb 2+ . Ba 2+ doping in perovskite (mol% <5) slightly enlarges the optic energy gap by conduction band minimum(CBM) upshifting to vacuum energy level, which is due to the smaller electronegativity of Ba than Pb. The enlarged band gap is also verified by density function theory calculations. In n-i-p structure perovskite solar cells (PSCs), because of the higher CBM of doped perovskite, the Fermi energy difference between n and p side is enlarged and the electron injection from the perovskite to TiO 2 is improved. Thus, both the photovoltage and photocurrent are improved by small amount Ba 2+ doping, resulting optimized 17.4% efficiency under AM1.5. This work reveals the relationship between the doping element property and the energy band structure of the perovskite, and highlights the doping method to improve the performance of PSCs.

  9. The electronic and optical properties of CH3NH3MoI3 perovskite

    Science.gov (United States)

    Kansara, Shivam; Sonvane, Yogesh; Gupta, Sanjeev K.

    2018-05-01

    In this work, a first-principles theoretical study of hybrid perovskite CH3NH3MoI3 is performed using PBE exchange-correlation approximations in density functional theory. The results of electronic band structure are 0.90 eV (M-point: Direct) and 0.60 eV (R-X point: Indirect), respectively. We have also calculated the dielectric properties such as real, imaginary, extension coefficient (K) and reflectivity (R) properties of hybrid perovskite CH3NH3MoI3. The low-bandgap molecules are used to absorb near-IR range and typically having a bandgap smaller than 1.6 eV. This is particularly attractive in organic photovoltaics (OPV), photodetectors (PDs), and ambipolar field-effect transistors (FETs).

  10. Model predictions of ambient pollution concentration | Olaniyan ...

    African Journals Online (AJOL)

    The results show that the emission loads of the pollutants associated with the use of industrial boiler and power generating plant are in decreasing order of magnitude as NOx > CO > TSP > SO2 > VOC > SO,sub>3 and NOx > TSP > CO > HC > SO2 respectively. The emission load of SO2 is 74.6% in power generating plant, ...

  11. Espacio literario relevante sobre el problema del vendedor viajero (TSP: contenido, clasificación, métodos y campos de inspiración Relevant literary space on travelling salesman problem (TSP: contents, classification, methods and fields of inspiration

    Directory of Open Access Journals (Sweden)

    Jorge Ivan Pérez Rave

    2013-01-01

    Full Text Available Se describe y se analiza un espacio literario relevante sobre el Problema del Vendedor Viajero (TSP en términos de contenido, clases de TSP, métodos y campos de inspiración. Los datos empleados provinieron de los trabajos más citados en Scopus sobre el TSP, tanto a través de la historia como en el período 2006-2010. Se encontró que el TSP prevalece en las investigaciones, con enfoques tanto en el problema original como en sus variantes, entre las cuales se identificaron el TSP Múltiple y el TSP Probabilístico. Entre los principales campos de inspiración para resolver el TSP están la evolución biológica y su base genético-molecular, el comportamiento de hormigas reales, la termodinámica, las estrategias sistemáticas para combinar reglas de decisión y la búsqueda de vecindades. Hoy día se tiende a desarrollar métodos híbridos, especialmente integrando enfoques globales con búsquedas locales, y se identifica la necesidad de introducir nuevos campos de inspiración.This paper describes and analyzes, in terms of content, the types of TSP, methods and fields of inspiration - the most relevant "literary space" on TSP. It is built based on the top most cited on the TSP history and the Top 10 cited from 2006 to 2010. The study of TSP still prevails in Research, focusing on the original problem and its variants: Multiple TSP (m-TSP and Probabilistic TSP (PTSP. Evidence shows that there has been progress in the development of TSP solving methods, highlighted by various inspiration fields: biological evolution, behavior of real ants, thermodynamics, systematic strategies for combining decision rules, and neighborhood search. There is a tendency to develop hybrid methods, in particular by integrating global approaches to local search. There is need to introduce new fields of inspiration.

  12. A Bibliography of the Personal Software Process (PSP) and the Team Software Process (TSP)

    Science.gov (United States)

    2009-10-01

    tspsymposium/ Padula , Alan. ―TSP-Agile Showdown: The Gun Smoke Clears.‖ Proceedings of the TSP Sympo- sium (September 2009). http://www.sei.cmu.edu...www.sei.cmu.edu/tspsymposium/ Padula , Alan. ―TSP—Agile Showdown.‖ Proceedings of the TSP Symposium (September 2008). http://www.sei.cmu.edu

  13. Temperature Switch PCR (TSP: Robust assay design for reliable amplification and genotyping of SNPs

    Directory of Open Access Journals (Sweden)

    Mather Diane E

    2009-12-01

    Full Text Available Abstract Background Many research and diagnostic applications rely upon the assay of individual single nucleotide polymorphisms (SNPs. Thus, methods to improve the speed and efficiency for single-marker SNP genotyping are highly desirable. Here, we describe the method of temperature-switch PCR (TSP, a biphasic four-primer PCR system with a universal primer design that permits amplification of the target locus in the first phase of thermal cycling before switching to the detection of the alleles. TSP can simplify assay design for a range of commonly used single-marker SNP genotyping methods, and reduce the requirement for individual assay optimization and operator expertise in the deployment of SNP assays. Results We demonstrate the utility of TSP for the rapid construction of robust and convenient endpoint SNP genotyping assays based on allele-specific PCR and high resolution melt analysis by generating a total of 11,232 data points. The TSP assays were performed under standardised reaction conditions, requiring minimal optimization of individual assays. High genotyping accuracy was verified by 100% concordance of TSP genotypes in a blinded study with an independent genotyping method. Conclusion Theoretically, TSP can be directly incorporated into the design of assays for most current single-marker SNP genotyping methods. TSP provides several technological advances for single-marker SNP genotyping including simplified assay design and development, increased assay specificity and genotyping accuracy, and opportunities for assay automation. By reducing the requirement for operator expertise, TSP provides opportunities to deploy a wider range of single-marker SNP genotyping methods in the laboratory. TSP has broad applications and can be deployed in any animal and plant species.

  14. Measurement of Ambient Air Particle (TSP, PM10, PM2,5) Around Candidate Location of PLTN Semenanjung Lemahabang

    International Nuclear Information System (INIS)

    AgusGindo S; Budi Hari H

    2008-01-01

    Measurement analysis of ambient air particle (TSP, PM 10 , PM 2,5 ) around location candidate of PLTN (Power Station of Nuclear Energy) Semenanjung Lemahabang has been carried out. The measurement was conducted in May 2007 with a purpose to providing information about concentration of ambient air particle (TSP, PM 10 , PM 2,5 ) and diameter distribution of its air particle. The measurement was conducted in three locations i.e. 1). Balong village 2). Bayuran 3). Bondo. Concentration of TSP, PM 10 , and PM 2,5 per 24 hours in all measured locations in area candidate of PLTN exceed quality standard of national ambient air is specified by government. All measurement locations for the TSP, PM 10 , and PM 2,5 was include category of ISPU (Standard Index of Air Pollution) moderate. (author)

  15. Irradiated NH3 and ND3 - two new target materials for polarized targets

    International Nuclear Information System (INIS)

    Meyer, W.

    1982-11-01

    A study of dynamic nuclear polarization (DNP) in NH 3 and ND 3 was made at the Bonn 2.5 GeV electron synchrotron. The paramagnetic radicals in the polycristalline ammonia beads were created by irradiation in the high intensity 20 MeV electron beam (> 10 14 electrons/sec) of the injection linac. During irradiation the ammonia beads, produced by dropping into liquid nitrogen, were cooled in liquid argon at approx.= 90 K. DNP measurements were performed at 1 K, 0.5 K and 0.2 K in a 2.5 T magnetic field. Samples of NH 3 , prepared in this way, yielded a maximum proton polarization of 66% at a temperature of 0.5 K with a short polarization build-up time of 9 minutes. ND 3 could be polarized at a temperature of 0.2 K up to 31%. The radiation resistance of the polarization of NH 3 is better than that of butanol. (orig.)

  16. Measurement of VOC permeability of polymer bags and VOC solubility in polyethylene drum liner

    International Nuclear Information System (INIS)

    Liekhus, K.J.; Peterson, E.S.

    1995-03-01

    A test program conducted at the Idaho National Engineering Laboratory (INEL) investigated the use of a transport model to estimate the volatile organic compound (VOC) concentration in the void volume of a waste drum. Unsteady-state VOC transport model equations account for VOC permeation of polymer bags, VOC diffusion across openings in layers of confinement, and VOC solubility in a polyethylene drum liner. In support of this program, the VOC permeability of polymer bags and VOC equilibrium concentration in a polyethylene drum liner were measured for nine VOCs. The VOCs used in experiments were dichloromethane, carbon tetrachloride, cyclohexane, toluene, 1,1,1-trichloroethane, methanol, 1,1,2-trichloro-1,2,2-trifluoroethane (Freon-113), trichloroethylene, and p-xylene. The experimental results of these measurements as well as a method of estimating both parameters in the absence of experimental data are described in this report

  17. Order-disorder phase transition in the peroxidovanadium complex NH4[VO(O2)2(NH3)].

    Science.gov (United States)

    Schwendt, Peter; Gyepes, Róbert; Chrappová, Jana; Němec, Ivan; Vaněk, Přemysl

    2018-07-05

    Complex NH 4 [VO(O 2 ) 2 (NH 3 )] (1) undergoes an order-disorder phase transition at T c ~258K. This transition is accompanied by change in the space group of the orthorhombic lattice and also by significant structural rearrangements of the constituent molecules, which are pertinent mostly to their NH 4 + ions and their ammonia ligands. The low-temperature solid state IR and Raman spectra of 1 were corroborated by solid-state computations that employed Gaussian functions as the basis set. Results of these computations yielded excellent agreement with experimental data. On the curves of temperature dependence of vibrational modes, the phase transition is expressed by an abrupt change of the slope above T c . Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Rietveld refinement of the crystal structure of perovskite solar cells using CH3NH3PbI3 and other compounds

    Science.gov (United States)

    Ando, Yuji; Ohishi, Yuya; Suzuki, Kohei; Suzuki, Atsushi; Oku, Takeo

    2018-01-01

    The crystal structures of perovskite thin films including CH3NH3PbI3, CH3NH3Pb1-xSbxI3, and CH3NH3PbI3-yCly in the solar cell configuration were studied by using Rietveld refinement. For the CH3NH3PbI3 and CH3NH3Pb1-xSbxI3 samples, satisfactory agreement with the measured profiles was obtained with a weighted profile R-factor (Rwp) of as low as 3%. It was shown that the site occupancy of methylammonium (MA) was decreased in the antimonized cell due to the compensation effect of an increased positive charge brought about by replacing Pb2+ with Sb3+. Photovoltaic measurements showed that the power conversion efficiency was enhanced by adding a small amount of Sb to the CH3NH3PbI3 cell, but it was monotonically decreased as the mole fraction of Sb exceeded 0.03. This variation of the conversion efficiency was considered as a result of suppressed crystallization of PbI2 and carrier recombination via MA vacancies in the antimonized cells. In the case of CH3NH3PbI2.88Cl0.12 sample, the agreement with the measured profile with an Rwp of as high as 7% suggested the co-existence of cubic and tetragonal phases in the chlorinated cell.

  19. General k-opt submoves for the Lin-Kernighan TSP heuristic

    DEFF Research Database (Denmark)

    Helsgaun, Keld

    2009-01-01

    Local search with k-exchange neighborhoods, k-opt, is the most widely used heuristic method for the traveling salesman problem (TSP). This paper presents an effective implementation of k-opt in LKH-2, a variant of the Lin–Kernighan TSP heuristic. The effectiveness of the implementation...

  20. Study of various NH4+/NO3- mixtures for enhancing growth of potatoes

    Science.gov (United States)

    Cao, W.; Tibbitts, T. W.

    1993-01-01

    Two experiments were conducted to determine the effects of various NH4(+)-N/NO3(-)-N percentages on growth and mineral concentrations in potato (Solanum tuberosum L.) plants using a non-recirculating nutrient film system in a controlled environment. The first experiment included six NH4(+)-N/NO3(-)-N percentages at 0/100, 20/80, 40/60, 60/40, 80/20, and 100/0 with the same total N concentration of 4 mM. The second experiment included six NH4(+)-N/NO3(-)-N percentages at 0/100, 4/96, 8/92, 12/88, 16/84, and 20/80 again with the same total N of 4 mM. In each experiment, plants were harvested 35 days after transplanting when tubers had been initiated and started to enlarge. Dry weights of shoots, tubers, and whole plant at the harvest were increased significantly with all mixed nitrogen treatments as compared with single NH4+ or NO3- form. The enhanced growth with mixed nitrogen was greatest at 8% to 20% NH4(+)-N. Also, the concentrations and accumulation of total N in the shoots and roots were greater with mixed nitrogen than with separate NH4+ or NO3- nutrition. With NH4+ present in the solutions, the concentrations of P and Cl in the shoots were increased compared to NO3- alone, whereas the tissue concentrations of Ca and Mg were decreased. It was concluded that nitrogen fertilization provided with combined NH4+ and NO3- forms, even at small proportions of NH4+, can enhance nitrogen uptake and productivity in potato plants.

  1. Verification of T2VOC using an analytical solution for VOC transport in vadose zone

    Energy Technology Data Exchange (ETDEWEB)

    Shan, C. [Lawrence Berkeley Laboratory, Berkeley, CA (United States)

    1995-03-01

    T2VOC represents an adaption of the STMVOC to the TOUGH2 environment. In may contaminated sites, transport of volatile organic chemicals (VOC) is a serious problem which can be simulated by T2VOC. To demonstrate the accuracy and robustness of the code, we chose a practical problem of VOC transport as the test case, conducted T2VOC simulations, and compared the results of T2VOC with those of an analytical solution. The agreements between T2VOC and the analytical solutions are excellent. In addition, the numerical results of T2VOC are less sensitive to grid size and time step to a certain extent.

  2. NH3 Abatement in Fluidized Bed Co-Gasification of RDF and Coal

    Science.gov (United States)

    Gulyurtlu, I.; Pinto, Filomena; Dias, Mário; Lopes, Helena; André, Rui Neto; Cabrita, I.

    Gasification of wastes may come out as an alternative technology to produce a gas with many potential applications, from direct burning in a boiler or motor to the production of synthetic chemicals and hydrogen. High tar production and high operational costs are preventing gasification wider dissemination. Besides these problems, the presence of NH3 in the syngas may have a negative impact as it can be converted into nitrogen oxides if the gas is further burnt. To reduce NH3 formation it is required a full understanding of how operational parameters contribute to the formation/reduction of this pollutant. A full studyon the effect of fuel composition, temperature and equivalence ratio on the formation of NH3 is given. Experimental results are compared to theoretical ones obtained with FactSage software. It is also analyzed the effect of feedstock mineral matterin NH3 release during gasification. Toaccomplish a significant decrease in the release of NH3, different catalysts and sorbents were tested with the aim of achieving high energy conversions and low environmental impact.

  3. Molecular modelling of the decomposition of NH{sub 3} over CoO(100)

    Energy Technology Data Exchange (ETDEWEB)

    Shojaee, Kambiz; Haynes, Brian S.; Montoya, Alejandro, E-mail: alejandro.montoya@sydney.edu.au

    2015-04-15

    Spin-polarised density functional theory using the PBE + U approach are used to determine reaction pathways of successive NH{sub 3} dehydrogenation on the CoO(100) surface. NH{sub 3} dehydrogenation promotes noticeable displacements of the surface CoO sites, in particular due to the binding of NH{sub 2} and H species. Surface lattice O has low activity towards dehydrogenation, reflected in energy barriers that are in the range of 292 kJ mol{sup −1} to 328 kJ mol{sup −1}. There is a preference of surface NH{sub 3} dehydrogenation to N{sub 2} rather than towards NO, due to a high-energy penalty of surface O vacancy formation. The presence of CoO in cobalt oxide catalysts not only may decline the ammonia conversion but also alter the selectivity towards N{sub 2} rather than NO. - Highlights: • Minimum reactions pathways of ammonia decomposition were studied using density functional theory. • The bonding characteristics of NH{sub x} and H on the CoO(100) surface were analysed using Layer-projected density of states. • Dehydrogenations of NH{sub 3}, NH{sub 2} and NH are highly activated. • The presence of strongly bound lattice oxygen favours the ammonia decomposition towards N{sub 2}.

  4. The threonine protease activity of testes-specific protease 50 (TSP50 is essential for its function in cell proliferation.

    Directory of Open Access Journals (Sweden)

    Yu-Yin Li

    Full Text Available BACKGROUND: Testes-specific protease 50 (TSP50, a newly discovered threonine enzyme, has similar amino acid sequences and enzymatic structures to those of many serine proteases. It may be an oncogene. TSP50 is up-regulated in breast cancer epithelial cells, and ectopic expression of TSP50 in TSP50-deficient Chinese hamster ovary (CHO cells has been found to promote cell proliferation. However, the mechanisms by which TSP50 exerts its growth-promoting effects are not yet fully understood. METHODOLOGY/PRINCIPAL FINDINGS: To delineate whether the threonine protease activity of TSP50 is essential to its function in cell proliferation, we constructed and characterized a mutant TSP50, called TSP50 T310A, which was identified as a protease-dead mutant of TSP50. By a series of proliferation analyses, colony formation assays and apoptosis analyses, we showed that T310A mutation significantly depresses TSP50-induced cell proliferation in vitro. Next, the CHO stable cell line expressing either wild-type or T310A mutant TSP50 was injected subcutaneously into nude mice. We found that the T310A mutation could abolish the tumorigenicity of TSP50 in vivo. A mechanism investigation revealed that the T310A mutation prevented interaction between TSP50 and the NF-κBIκBα complex, which is necessary for TSP50 to perform its function in cell proliferation. CONCLUSION: Our data highlight the importance of threonine 310, the most critical protease catalytic site in TSP50, to TSP50-induced cell proliferation and tumor formation.

  5. Synthesis of 15N-enriched urea (CO(15NH22 from 15NH3, CO, and S in a discontinuous process

    Directory of Open Access Journals (Sweden)

    C. R. Sant Ana Filho

    2012-12-01

    Full Text Available CO(15NH22 enriched with the stable isotope 15N was synthesized based on a reaction involving CO, 15NH3, and S in the presence of CH3OH. The method differs from the industrial method; a stainless steel reactor internally lined with polytetrafluoroethylene (PTFE was used in a discontinuous process under low pressure and temperature. The yield of the synthesis was evaluated as a function of the parameters: the amount of reagents, reaction time, addition of H2S, liquid solution and reaction temperature. The results showed that under optimum conditions (1.36, 4.01, and 4.48 g of 15NH3, CO, and S, respectively, 40 ml CH3OH, 40 mg H2S, 100 ºC and 120 min of reaction 1.82 g (yield 76.5% of the compound was obtained per batch. The synthesized CO(15NH22 contained 46.2% N, 0.55% biuret, melting point of 132.55 ºC and did not exhibit isotopic fractionation. The production cost of CO(15NH22 with 90.0 at. % 15N was US$ 238.60 per gram.

  6. Effects of CsBr addition on the performance of CH3NH3PbI3-xClx-based solar cells

    Science.gov (United States)

    Ueoka, Naoki; Oku, Takeo; Ohishi, Yuya; Tanaka, Hiroki; Suzuki, Atsushi; Sakamoto, Hiroki; Yamada, Masahiro; Minami, Satoshi; Tsukada, Shinichiro

    2018-01-01

    Perovskite-type photovoltaic devices were prepared by a spin-coating method using a precursor solution of CH3NH3I and lead(II) chloride in N,N-dimethylformamide. Effects of cesium bromide (CsBr) addition on the photovoltaic properties and microstructures of the perovskite phase were investigated. The fill factor was increased by adding the CsBr to the CH3NH3PbI3-xClx precursor solution, which resulted in increase of the conversion efficiency. The crystallinity of the CH3NH3PbI3-xClx perovskite phase was also improved by adding the CsBr to the H3NH3PbI3-xClx precursor solution.

  7. Enhanced photovoltaic performance of CH3NH3PbBrXI3-X-based perovskite solar cells via anti-solvent extraction

    Science.gov (United States)

    Jiang, Zhaoyi; Zhang, Weijia; Lu, Chaoqun; Ma, Denghao; Liu, Haixu; Yu, Wei; Zhang, Yu; Ma, Qiang; Zhang, Yulong

    2018-06-01

    In this paper, the two-step sequential deposition method was used to prepare the CH3NH3PbBrXI3-X films by introducing CH3NH3Br in the precursors. The surface morphology of the PbI2 films was controlled by anti-solvent extraction (ASE) to improve the microstructure and photo-physical properties of the perovskite films. It was noteworthy that, compared to the compact PbI2 films, the porous PbI2 films facilitated the growth of crystals and bromine incorporation in films, and the prepared perovskite films exhibited enlarged grain size, increased light absorption, enhanced Br incorporation and prolonged carrier lifetime, which resulted in excellent photo-electrical properties of the CH3NH3PbBrXI3-X films. With porous PbI2 templates, the inverted planar perovskite solar cells based on films with appropriate Br incorporation (CH3NH3Br/CH3NH3I mole ratio = 3/7) showed a photovoltaic conversion efficiency (PCE) of 14.9%, and the stability of the devices in air was elevated. Consequently, the high-quality CH3NH3PbBrXI3-X films can be obtained with porous PbI2 templates for improving the performance of the perovskite solar cells.

  8. Sequence of phase transitions in (NH4)3SiF7.

    Science.gov (United States)

    Mel'nikova, S V; Molokeev, M S; Laptash, N M; Pogoreltsev, E I; Misyul, S V; Flerov, I N

    2017-02-21

    Single crystals of silicon double salt (NH 4 ) 3 SiF 7 = (NH 4 ) 2 SiF 6 ·NH 4 F = (NH 4 ) 3 [SiF 6 ]F were grown and studied by the methods of polarization optics, X-ray diffraction and calorimetry. A sequence of symmetry transformations with the temperature change was established: P4/mbm (Z = 2) (G 1 ) ↔ Pbam (Z = 4) (G 2 ) ↔ P2 1 /c (Z = 4) (G 3 ) ↔ P1[combining macron] (Z = 4) (G 4 ) ↔ P2 1 /c (Z = 8) (G 5 ). Crystal structures of different phases were determined. The experimental data were also interpreted by a group-theoretical analysis of the complete condensate of order parameters taking into account critical and noncritical atomic displacements. Strengthening of the N-HF hydrogen bonds can be a driving force of the observed phase transitions.

  9. Synthesis and structural characterization of two cobalt phosphites: 1-D (H3NC6H4NH3)Co(HPO3)2 and 2-D (NH4)2Co2(HPo3)3

    International Nuclear Information System (INIS)

    Cheng, C.-C.; Chang, W.-K.; Chiang, R.-K.; Wang, S.-L.

    2010-01-01

    Two new cobalt phosphites, (H 3 NC 6 H 4 NH 3 )Co(HPO 3 ) 2 (1) and (NH 4 ) 2 Co 2 (HPO 3 ) 3 (2), have been synthesized and characterized by single-crystal X-ray diffraction. All the cobalt atoms of 1 are in tetrahedral CoO 4 coordination. The structure of 1 comprises twisted square chains of four-rings, which contain alternating vertex-shared CoO 4 tetrahedra and HPO 3 groups. These chains are interlinked with trans-1,4-diaminocyclohexane cations by hydrogen bonds. The 2-D structure of 2 comprises anionic complex sheets with ammonium cations present between them. An anionic complex sheet contains three-deck phosphite units, which are interconnected by Co 2 O 9 to form complex layers. Magnetic susceptibility measurements of 1 and 2 showed that they have a weak antiferromagnetic interaction. - Graphical abstract: The 2-D structure of (NH 4 ) 2 Co 2 (HPO 3 ) 3 comprises anionic complex sheets with ammonium cations present between them. An anionic complex sheet contains three-deck phosphite units, which are interconnected by dimmeric Co 2 O 9 to form complex layers.

  10. The international research progress of Ammonia(NH3) emissions and emissions reduction technology in farmland ecosystem

    Science.gov (United States)

    Yang, W. Z.; Jiao, Y.

    2017-03-01

    NH3 is the important factor leading to the grey haze, and one of the main causes of environmental problems of serious ecological imbalance, such as acid rain and air quality deterioration. The fertilizer excessive application of the current farmland results NH3 emissions intensity greatly. In order to clear the farmland NH3 emissions research status and achievements, the literature of farmland NH3 emission related were retrievaled by the SCI journals and Chinese science citation database. Some factors of NH3 emission were analyzed such as soil factors, climate factors and farmland management measures. The research progress was inductived on farmland NH3 emission reduction technology. The results will help to clarify farmland NH3 emissions research progress. The theoretical guidance was provided on the future of farmland NH3 emissions research.

  11. Field-effect transistors with high mobility and small hysteresis of transfer characteristics based on CH3NH3PbBr3 films

    Science.gov (United States)

    Aleshin, A. N.; Shcherbakov, I. P.; Trapeznikova, I. N.; Petrov, V. N.

    2017-12-01

    Field-effect transistor (FET) structures based on soluble organometallic perovskites, CH3NH3PbBr3, were obtained and their electrical properties were studied. FETs made of CH3NH3PbBr3 films possess current- voltage characteristics (IVs) typical for ambipolar FETs with saturation regime. The transfer characteristics of FETs based on CH3NH3PbBr3 have an insignificant hysteresis and slightly depend on voltage at the source-drain. Mobilities of charge carriers (holes) calculated from IVs of FETs based on CH3NH3PbBr3 at 300 K in saturation and weak field regimes were 5 and 2 cm2/V s, respectively, whereas electron mobility is 3 cm2/V s, which exceeds the mobility value 1 cm2/V s obtained earlier for FETs based on CH3NH3PbI3.

  12. Electron transport in NH3/NO2 sensed buckled antimonene

    Science.gov (United States)

    Srivastava, Anurag; Khan, Md. Shahzad; Ahuja, Rajeev

    2018-04-01

    The structural and electronic properties of buckled antimonene have been analysed using density functional theory based ab-initio approach. Geometrical parameters in terms of bond length and bond angle are found close to the single ruffle mono-layer of rhombohedral antimony. Inter-frontier orbital analyses suggest localization of lone pair electrons at each atomic centre. Phonon dispersion along with high symmetry point of Brillouin zone does not signify any soft mode. With an electronic band gap of 1.8eV, the quasi-2D nano-surface has been further explored for NH3/NO2 molecules sensing and qualities of interaction between NH3/NO2 gas and antimonene scrutinized in terms of electronic charges transfer. A current-voltage characteristic has also been analysed, using Non Equilibrium Green's function (NEGF), for antimonene, in presence of incoming NH3/NO2 molecules.

  13. Imaging spinal cord atrophy in progressive myelopathies: HTLV-I-associated neurological disease (HAM/TSP) and multiple sclerosis (MS).

    Science.gov (United States)

    Azodi, Shila; Nair, Govind; Enose-Akahata, Yoshimi; Charlip, Emily; Vellucci, Ashley; Cortese, Irene; Dwyer, Jenifer; Billioux, B Jeanne; Thomas, Chevaz; Ohayon, Joan; Reich, Daniel S; Jacobson, Steven

    2017-11-01

    Previous work measures spinal cord thinning in chronic progressive myelopathies, including human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and multiple sclerosis (MS). Quantitative measurements of spinal cord atrophy are important in fully characterizing these and other spinal cord diseases. We aimed to investigate patterns of spinal cord atrophy and correlations with clinical markers. Spinal cord cross-sectional area was measured in individuals (24 healthy controls [HCs], 17 asymptomatic carriers of HTLV-1 (AC), 47 HAM/TSP, 74 relapsing-remitting MS [RRMS], 17 secondary progressive MS [SPMS], and 40 primary progressive MS [PPMS]) from C1 to T10. Clinical disability scores, viral markers, and immunological parameters were obtained for patients and correlated with representative spinal cord cross-sectional area regions at the C2 to C3, C4 to C5, and T4 to T9 levels. In 2 HAM/TSP patients, spinal cord cross-sectional area was measured over 3 years. All spinal cord regions are thinner in HAM/TSP (56 mm 2 [standard deviation, 10], 59 [10], 23 [5]) than in HC (76 [7], 83 [8], 38 [4]) and AC (71 [7], 78 [9], 36 [7]). SPMS (62 [9], 66 [9], 32 [6]) and PPMS (65 [11], 68 [10], 35 [7]) have thinner cervical cords than HC and RRMS (73 [9], 77 [10], 37 [6]). Clinical disability scores (Expanded Disability Status Scale [p = 0.009] and Instituto de Pesquisas de Cananeia [p = 0.03]) and CD8 + T-cell frequency (p = 0.04) correlate with T4 to T9 spinal cord cross-sectional area in HAM/TSP. Higher cerebrospinal fluid HTLV-1 proviral load (p = 0.01) was associated with thinner spinal cord cross-sectional area. Both HAM/TSP patients followed longitudinally showed thoracic thinning followed by cervical thinning. Group average spinal cord cross-sectional area in HAM/TSP and progressive MS show spinal cord atrophy. We further hypothesize in HAM/TSP that is possible that neuroglial loss from a thoracic inflammatory

  14. MARVEL analysis of the measured high-resolution spectra of 14NH3

    International Nuclear Information System (INIS)

    Al Derzi, Afaf R.; Furtenbacher, Tibor; Tennyson, Jonathan; Yurchenko, Sergei N.; Császár, Attila G.

    2015-01-01

    Accurate, experimental rotational–vibrational energy levels and line positions, with associated labels and uncertainties, are reported for the ground electronic state of the symmetric-top 14 NH 3 molecule. All levels and lines are based on critically reviewed and validated high-resolution experimental spectra taken from 56 literature sources. The transition data are in the 0.7–17 000 cm −1 region, with a large gap between 7000 and 15 000 cm −1 . The MARVEL (Measured Active Rotational–Vibrational Energy Levels) algorithm is used to determine the energy levels. Out of the 29 450 measured transitions 10 041 and 18 947 belong to ortho- and para- 14 NH 3 , respectively. A careful analysis of the related experimental spectroscopic network (SN) allows 28 530 of the measured transitions to be validated, 18 178 of these are unique, while 462 transitions belong to floating components. Despite the large number of spectroscopic measurements published over the last 80 years, the transitions determine only 30 vibrational band origins of 14 NH 3 , 8 for ortho- and 22 for para- 14 NH 3 . The highest J value, where J stands for the rotational quantum number, for which an energy level is validated is 31. The number of experimental-quality ortho- and para- 14 NH 3 rovibrational energy levels is 1724 and 3237, respectively. The MARVEL energy levels are checked against ones in the BYTe first-principles database, determined previously. The lists of validated lines and levels for 14 NH 3 are deposited in the Supporting Information to this paper. Combination of the MARVEL energy levels with first-principles absorption intensities yields a huge number of experimental-quality rovibrational lines, which should prove to be useful for the understanding of future complex high-resolution spectroscopy on 14 NH 3 ; these lines are also deposited in the Supporting Information to this paper

  15. MARVEL analysis of the measured high-resolution spectra of 14NH3

    Science.gov (United States)

    Al Derzi, Afaf R.; Furtenbacher, Tibor; Tennyson, Jonathan; Yurchenko, Sergei N.; Császár, Attila G.

    2015-08-01

    Accurate, experimental rotational-vibrational energy levels and line positions, with associated labels and uncertainties, are reported for the ground electronic state of the symmetric-top 14NH3 molecule. All levels and lines are based on critically reviewed and validated high-resolution experimental spectra taken from 56 literature sources. The transition data are in the 0.7-17 000 cm-1 region, with a large gap between 7000 and 15 000 cm-1. The MARVEL (Measured Active Rotational-Vibrational Energy Levels) algorithm is used to determine the energy levels. Out of the 29 450 measured transitions 10 041 and 18 947 belong to ortho- and para-14NH3, respectively. A careful analysis of the related experimental spectroscopic network (SN) allows 28 530 of the measured transitions to be validated, 18 178 of these are unique, while 462 transitions belong to floating components. Despite the large number of spectroscopic measurements published over the last 80 years, the transitions determine only 30 vibrational band origins of 14NH3, 8 for ortho- and 22 for para-14NH3. The highest J value, where J stands for the rotational quantum number, for which an energy level is validated is 31. The number of experimental-quality ortho- and para-14NH3 rovibrational energy levels is 1724 and 3237, respectively. The MARVEL energy levels are checked against ones in the BYTe first-principles database, determined previously. The lists of validated lines and levels for 14NH3 are deposited in the Supporting Information to this paper. Combination of the MARVEL energy levels with first-principles absorption intensities yields a huge number of experimental-quality rovibrational lines, which should prove to be useful for the understanding of future complex high-resolution spectroscopy on 14NH3; these lines are also deposited in the Supporting Information to this paper.

  16. Tunable far infrared laser spectroscopy of van der Waals bonds: Ar-NH3

    International Nuclear Information System (INIS)

    Gwo, Dz-Hung; California Univ., Berkeley, CA

    1989-11-01

    Hyperfine resolved vibration-rotation-tunneling spectra of Ar--NH 3 and (NH 3 ) 2 , generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar--NH 3 , and the other six belong to (NH 3 ) 2 . To facilitate the intermolecular vibrational assignment for Ar--NH 3 , a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states. An anomalous vibronically allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar--NH 3 centered at 26.470633(17) cm -1 can correlate only to either the fundamental dimeric stretching band for the A 2 states with the NH 3 inversional quantum number v i = 1, or the K a = 0 left-arrow 0 subband of the lowest internal-rotation-inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require far infrared data and a dynamical model incorporating a potential surface

  17. Crystallographic Investigations into Properties of Acentric Hybrid Perovskite Single Crystals NH(CH3)3SnX3(X = Cl, Br)

    KAUST Repository

    Dang, Yangyang

    2016-10-11

    The hybrid perovskites with special optoelectronic properties have attracted more attention to the scientific and industrial applications. However, because of the toxicity and instability of lead complexes, there is interest in finding a nontoxic substitute for the lead in the halides perovskites and solving the ambiguous crystal structures and phase transition of NH(CH3)3SnX3 (X = Cl, Br). Here, we report the bulk crystal growths and different crystal morphologies of orthorhombic hybrid perovskites NH(CH3)3SnX3 (X = Cl, Br) in an ambient atmosphere by bottom-seeded solution growth (BSSG) method. More importantly, detailed structural determination and refinements, phase transition, band gap, band structure calculations, nonlinear optical (NLO) properties, XPS, thermal properties, and stability of NH(CH3)3SnX3 (X = Cl, Br) single crystals are demonstrated. NH(CH3)3SnCl3 single crystal undergoes reversible structural transformation from orthorhombic space group Cmc21 (no. 36) to monoclinic space group Cc (no. 9) and NH(CH3)3SnBr3 belongs to the orthorhombic space group Pna21 (no. 33) by DSC, single-crystal X-ray diffraction and temperature-dependent SHG measurements, which clarify the former results. These results should pave the way for further studies of these materials in optoelectronics.

  18. Study of NH3 Line Intensities in the THz and Far-IR Region

    Science.gov (United States)

    Yu, Shanshan

    Ammonia (NH3) exists in the interstellar medium, late-type stars and giant planets of our solar system. Its temperature and abundance profiles in these environments, which are derived with its line parameters as fixed input , are commonly used to provide constraints on retrieving minor species. Therefore NH3 line parameters are essential for interpreting astrophysical and planetary spectra from Herschel, SOFIA, ALMA and JWST. However, our work under a predecessor grant with the APRA program revealed significant deficiencies in NH3 intensities in the terahertz and FIR region, including some weak Delta(K)=3 forbidden transitions predicted to be 100 times stronger. The Delta(K)=3 transitions are the ones connecting levels with different K values and therefore the only way other than collisions and l-doubled states to excite NH3 to K>0 levels. Their intensities have to be corrected to explain the observed high K excitation, such as the detection of NH3 (J,K) = (1,1), (2,2)&(14,14) and (18,18) transitions toward the galactic center star forming region Sgr B2, and to provide insights into the radiative- transfer vs. collision excitation mechanics of interstellar NH3. This proposal will remedy the serious deficiencies in the current databases involving NH3 line parameters in the terahertz and FIR region. We will target transitions with intensities greater than 10^{-23} cm-1/ (molecule/cm2) at 296 K, which will be among new astrophysical detections made by SOFIA, ALMA and JWST, and are 1000 times weaker than the strongest ground state transitions. We will retrieve new positions and intensities from existing laboratory spectra, use them to evaluate the current databases and ab initio calculations, and repair the line positions and intensities by replacing poorly calculated values with our new measurements. The proposed research will result in (1) a validated linelist containing the positions, intensities and lower state energies for the very important Delta(K)=3 NH3 FIR

  19. Thermal properties and phase transition in the fluoride, (NH4)3SnF7

    International Nuclear Information System (INIS)

    Kartashev, A.V.; Gorev, M.V.; Bogdanov, E.V.; Flerov, I.N.; Laptash, N.M.

    2016-01-01

    Calorimetric, dilatometric and differential thermal analysis studies were performed on (NH 4 ) 3 SnF 7 for a wide range of temperatures and pressures. Large entropy (δS 0 =22 J/mol K) and elastic deformation (δ(ΔV/V) 0 =0.89%) jumps have proven that the Pa-3↔Pm-3m phase transition is a strong first order structural transformation. A total entropy change of ΔS 0 =32.5 J/mol K is characteristic for the order–disorder phase transition, and is equal to the sum of entropy changes in the related material, (NH 4 ) 3 TiF 7 , undergoing transformation between the two cubic phases through the intermediate phases. Hydrostatic pressure decreases the stability of the high temperature Pm-3m phase in (NH 4 ) 3 SnF 7 , contrary to (NH 4 ) 3 TiF 7 , characterised by a negative baric coefficient. The effect of experimental conditions on the chemical stability of (NH 4 ) 3 SnF 7 was observed. - Graphical abstract: Strong first order structural transformation Pa-3↔Pm-3m in (NH 4 ) 3 SnF 7 is associated with very large total entropy change of ΔS 0 =32.5 J/mol K characteristic for the ordering processes and equal to the sum of entropy changes in the related (NH 4 ) 3 TiF 7 undergoing transformation between the same two cubic phases through the intermediate phases. - Highlights: • (NH 4 ) 3 SnF 7 undergoes strong first order Pa-3↔Pm-3m phase transition. • Anomalous behaviour of ΔC p and ΔV/V exists far below phase transition temperature. • Structural distortions are accompanied by huge total entropy change ΔS≈Rln50. • High pressure strongly increases the stability of Pa-3 phase in (NH 4 ) 3 SnF 7 . • Entropy of the Pa-3↔Pm-3m phase transition does not depend on pressure.

  20. The phytotoxic effects of present NH3 immissions

    International Nuclear Information System (INIS)

    Adaros, G.; Daemmgen, U.

    1994-01-01

    The phytotoxic effects of NH 3 have been known since the end of the previous century. The significance of ammonia as harmful substance or stressor even in ambient concentrations has been only realized and investigated during the last decades. This volume is aimed at accounting the effects produced by ambient doses of NH 3 . The entities relevant for the description of potential dose response relationships are discussed. The major source of potential dose response relationships are discussed. The major source of atmospheric pollution of ammonia and ammonium is intensive agriculture, in particular intensive cattle production. However, sources and transmission processes are not dealt with in this paper. Potential pathways of ammonia into the plants and the respective reaction mechanisms are discussed in detail. (orig./MG) [de

  1. UV photoprocessing of NH3 ice: photon-induced desorption mechanisms

    Science.gov (United States)

    Martín-Doménech, R.; Cruz-Díaz, G. A.; Muñoz Caro, G. M.

    2018-01-01

    Ice mantles detected on the surface of dust grains towards the coldest regions of the interstellar medium can be photoprocessed by the secondary ultraviolet (UV) field present in dense cloud interiors. In this work, we present UV-irradiation experiments under astrophysically relevant conditions of pure NH3 ice samples in an ultra-high vacuum chamber where solid samples were deposited on to a substrate at 8 K. The ice analogues were subsequently photoprocessed with a microwave-discharged hydrogen-flow lamp. The induced radiation and photochemistry led to the production of H2, N2 and N2H4. In addition, photodesorption to the gas phase of the original ice component, NH3, and two of the three detected photoproducts, H2 and N2, was observed thanks to a quadrupole mass spectrometer (QMS). Calibration of the QMS allowed quantification of the photodesorption yields, leading to Ypd (NH3) = 2.1^{+2.1}_{-1.0} × 10-3 molecules/{incident photon}, which remained constant during the whole experiments, while photodesorption of H2 and N2 increased with fluence, pointing towards an indirect photodesorption mechanism involving energy transfer for these species. Photodesorption yield of N2 molecules after a fluence equivalent to that experienced by ice mantles in space was similar to that of the NH3 molecules (Ypd (N2) = 1.7^{+1.7}_{-0.9} × 10-3 molecules/{incident photon}).

  2. An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements

    Directory of Open Access Journals (Sweden)

    E. Dammers

    2016-08-01

    Full Text Available Global distributions of atmospheric ammonia (NH3 measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (Nobs = 547 give a mean relative difference of −32.4 ± (56.3 %, a correlation r of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (−50 to +100 %.

  3. Effects of two litter amendments on air NH3 levels in broiler closed-houses

    Science.gov (United States)

    Atapattu, N. S. B. M; Lakmal, L. G. E.; Perera, P. W. A.

    2017-01-01

    Objective High NH3 emissions from poultry houses are reported to have negative impacts on health, welfare and safety of birds and humans, and on the environment. Objective of the present study was to determine the effects of two litter amendments on the NH3 levels in broiler closed houses under hot-humid conditions. Methods Giving a completely randomize design, nine closed houses, each housed 32,500 birds on paddy husk litter, were randomly allocated into two treatment (Mizuho; a bacterial culture mix and Rydall OE; an enzymatic biocatalyst) and control groups. NH3 levels were determined thrice a day (0600, 1200, and 1800 h), at three heights from the litter surface (30, 90, and 150 cm), at 20 predetermined locations of a house, from day 1 to 41. Results Rydall significantly reduced the NH3 level compared to control and Mizuho. NH3 levels at 30 cm were significantly higher than that of 90 and 150 cm. The NH3 levels at 30 cm height were higher than 25 ppm level from day 9, 11, and 13 in Mizuho, control, and Rydall groups, respectively to day 41. NH3 levels at 150 cm height were higher than maximum threshold limit of 50 ppm for human exposure from day 12, 14, and 15 in Mizuho, control, and Rydall groups, respectively to day 33. Being significantly different among each other, the NH3 level was highest and lowest at 0600 and 1800 h. Litter amendments had no significant effects on growth performance. Rydall significantly increased the litter N content on day 24. Conclusion It was concluded that the NH3 levels of closed house broiler production facilities under tropical condition are so high that both birds and workers are exposed to above recommended levels during many days of the growing period. Compared to microbial culture, the enzymatic biocatalyst was found to be more effective in reducing NH3 level. PMID:28423888

  4. Lead-free Perovskite Materials (NH4 )3 Sb2 Ix Br9-x.

    Science.gov (United States)

    Zuo, Chuantian; Ding, Liming

    2017-06-01

    A family of perovskite light absorbers (NH 4 ) 3 Sb 2 I x Br 9-x (0≤x≤9) was prepared. These materials show good solubility in ethanol, a low-cost, hypotoxic, and environmentally friendly solvent. The light absorption of (NH 4 ) 3 Sb 2 I x Br 9-x films can be tuned by adjusting I and Br content. The absorption onset for (NH 4 ) 3 Sb 2 I x Br 9-x films changes from 558 nm to 453 nm as x changes from 9 to 0. (NH 4 ) 3 Sb 2 I 9 single crystals were prepared, exhibiting a hole mobility of 4.8 cm 2  V -1  s -1 and an electron mobility of 12.3 cm 2  V -1  s -1 . (NH 4 ) 3 Sb 2 I 9 solar cells gave an open-circuit voltage of 1.03 V and a power conversion efficiency of 0.51 %. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Surface study of platinum decorated graphene towards adsorption of NH_3 and CH_4

    International Nuclear Information System (INIS)

    Rad, Ali Shokuhi; Pazoki, Hossein; Mohseni, Soheil; Zareyee, Daryoush; Peyravi, Majid

    2016-01-01

    To distinguish the potential of graphene sensors, there is a need to recognize the interaction between graphene sheet and adsorbing molecules. We used density functional theory (DFT) calculations to study the properties of pristine as well as Pt-decorated graphene sheet upon adsorption of NH_3 and CH_4 on its surface to exploit its potential to be as gas sensors for them. We found much higher adsorption, higher charge transfer, lower intermolecular distance, and higher orbital hybridizing upon adsorption of NH_3 and CH_4 gas molecules on Pt-decorated graphene compared to pristine graphene. Also our calculations reveal that the adsorption energies on Pt-decorated graphene sheet are in order of NH_3 >CH_4 which could be corresponded to the order of their sensitivity on this modified surface. We used orbital analysis including density of states as well as frontier molecular orbital study for all analyte-surface systems to more understanding the kind of interaction (physisorption or chemisorption). Consequently, the Pt-decorated graphene can transform the existence of NH_3 and CH_4 molecules into electrical signal and it may be potentially used as an ideal sensor for detection of NH_3 and CH_4 in ambient situation. - Highlights: • Pt-decorated graphene was investigated as an adsorbent for NH_3 and CH_4. • Much higher adsorption of NH_3 and CH_4 on Pt-decorated graphene than pristine graphene. • Higher adsorption of NH_3 compared to CH_4 on Pt-decorated graphene. • Pt influences the electronic structure of graphene.

  6. Cloning and analysis of a bifunctional methyltransferase/restriction endonuclease TspGWI, the prototype of a Thermus sp. enzyme family

    Directory of Open Access Journals (Sweden)

    Zylicz-Stachula Agnieszka

    2009-05-01

    Full Text Available Abstract Background Restriction-modification systems are a diverse class of enzymes. They are classified into four major types: I, II, III and IV. We have previously proposed the existence of a Thermus sp. enzyme family, which belongs to type II restriction endonucleases (REases, however, it features also some characteristics of types I and III. Members include related thermophilic endonucleases: TspGWI, TaqII, TspDTI, and Tth111II. Results Here we describe cloning, mutagenesis and analysis of the prototype TspGWI enzyme that recognises the 5'-ACGGA-3' site and cleaves 11/9 nt downstream. We cloned, expressed, and mutagenised the tspgwi gene and investigated the properties of its product, the bifunctional TspGWI restriction/modification enzyme. Since TspGWI does not cleave DNA completely, a cloning method was devised, based on amino acid sequencing of internal proteolytic fragments. The deduced amino acid sequence of the enzyme shares significant sequence similarity with another representative of the Thermus sp. family – TaqII. Interestingly, these enzymes recognise similar, yet different sequences in the DNA. Both enzymes cleave DNA at the same distance, but differ in their ability to cleave single sites and in the requirement of S-adenosylmethionine as an allosteric activator for cleavage. Both the restriction endonuclease (REase and methyltransferase (MTase activities of wild type (wt TspGWI (either recombinant or isolated from Thermus sp. are dependent on the presence of divalent cations. Conclusion TspGWI is a bifunctional protein comprising a tandem arrangement of Type I-like domains; particularly noticeable is the central HsdM-like module comprising a helical domain and a highly conserved S-adenosylmethionine-binding/catalytic MTase domain, containing DPAVGTG and NPPY motifs. TspGWI also possesses an N-terminal PD-(D/EXK nuclease domain related to the corresponding domains in HsdR subunits, but lacks the ATP-dependent translocase module

  7. X-ray and NQR studies of bromoindate(III) complexes. [C2H5NH3]4InBr7, [C(NH2)3]3InBr6, and [H3NCH2C(CH3)2CH2NH3]InBr5

    International Nuclear Information System (INIS)

    Iwakiri, Takeharu; Ishihara, Hideta; Terao, Hiromitsu; Lork, Enno; Gesing, Thorsten M.

    2017-01-01

    The crystal structures of [C 2 H 5 NH 3 ] 4 InBr 7 (1), [C(NH 2 ) 3 ] 3 InBr 6 (2), and [H 3 NCH 2 C(CH 3 ) 2 CH 2 NH 3 ]InBr 5 (3) were determined at 100(2) K: monoclinic, P2 1 /n, a=1061.94(3), b=1186.40(4), c=2007.88(7) pm, β= 104.575(1) , Z=4 for 1; monoclinic, C2/c, a=3128.81(12), b=878.42(3), c=2816.50(10) pm, β=92.1320(10) , Z=16 for 2; orthorhombic, P2 1 2 1 2 1 , a=1250.33(5), b=1391.46(6), c=2503.22(9) pm, Z=4 for 3. The structure of 1 contains an isolated octahedral [InBr 6 ] 3- ion and a Br - ion. The structure of 2 contains three different isolated octahedral [InBr 6 ] 3- ions. The structure of 3 has a corner-shared double-octahedral [In 2 Br 11 ] 5- ion and an isolated tetrahedral [InBr 4 ] - ion. The 81 Br nuclear quadrupole resonance (NQR) lines of the terminal Br atoms of the compounds are widely spread in frequency, and some of them show unusual positive temperature dependence. These observations manifest the N-H..Br-In hydrogen bond networks developed between the cations and anions to stabilize the crystal structures. The 81 Br NQR and differential thermal analysis (DTA) measurements have revealed the occurrence of unique phase transitions in 1 and 3. When the bond angles were estimated from the electric field gradient (EFG) directions calculated by the molecular orbital (MO) methods, accurate values were obtained for [InBr 6 ] 3- of 1 and for [In 2 Br 11 ] 5- and [InBr 4 ] - of 3, except for several exceptions in those for the latter two ions. On the other hand, the calculations of 81 Br NQR frequencies have produced up to 1.4 times higher values than the observed ones.

  8. Rotational Spectroscopy of the NH{sub 3}–H{sub 2} Molecular Complex

    Energy Technology Data Exchange (ETDEWEB)

    Surin, L. A.; Schlemmer, S. [I. Physikalisches Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne (Germany); Tarabukin, I. V. [Institute of Spectroscopy of Russian Academy of Sciences, Fizicheskaya Str. 5, 108840 Troitsk, Moscow, Russia (Russian Federation); Breier, A. A.; Giesen, T. F. [Institute of Physics, University of Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel (Germany); McCarthy, M. C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Avoird, A. van der, E-mail: surin@ph1.uni-koeln.de, E-mail: A.vanderAvoird@theochem.ru.nl [Theoretical Chemistry, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

    2017-03-20

    We report the first high resolution spectroscopic study of the NH{sub 3}–H{sub 2} van der Waals molecular complex. Three different experimental techniques, a molecular beam Fourier transform microwave spectrometer, a millimeter-wave intracavity jet OROTRON spectrometer, and a submillimeter-wave jet spectrometer with multipass cell, were used to detect pure rotational transitions of NH{sub 3}–H{sub 2} in the wide frequency range from 39 to 230 GHz. Two nuclear spin species, ( o )-NH{sub 3}–( o )-H{sub 2} and ( p )-NH{sub 3}–( o )-H{sub 2}, have been assigned as carriers of the observed lines on the basis of accompanying rovibrational calculations performed using the ab initio intermolecular potential energy surface (PES) of Maret et al. The experimental spectra were compared with the theoretical bound state results, thus providing a critical test of the quality of the NH{sub 3}–H{sub 2} PES, which is a key issue for reliable computations of the collisional excitation and de-excitation of ammonia in the dense interstellar medium.

  9. Selective Catalytic Reduction of NO with NH3 Over V-MCM-41 Catalyst.

    Science.gov (United States)

    Kwon, Woo Hyun; Park, Sung Hoon; Kim, Ji Man; Park, Su Bin; Jung, Sang-Chul; Kim, Sang Chai; Jeon, Jong-Ki; Park, Young-Kwon

    2016-02-01

    V-MCM-41, a mesoporous catalyst doped with V2O5, was applied for the first time to the removal of atmospheric NO. The quantity of V2O5 added was 10 wt% and 30 wt%. The characteristics of the synthesized catalysts were examined using XRD, N2 soprtion, and NH3-TPD. With increasing quantity of V2O5 added, specific surface area decreased and pore size increased. When the quantity of V2O5 was 10 wt%, the MCM-41 structure was retained, whereas considerable collapse of mesoporous structure was observed when 30 wt% V2O5 was added. The examination of acid characteristics using NH3-TPD showed that 30 wt% V-MCM-41 had the higher NH3 adsorption ability, implying that it would exhibit high activity for NH3 SCR reaction. In the NO removal experiments, 30 wt% V-MCM-41 showed much higher NO removal efficiency than 10 wt% V-MCM-41, which was attributed to its high NH3 adsorption ability.

  10. CH3NH3PbI3 grain growth and interfacial properties in meso-structured perovskite solar cells fabricated by two-step deposition

    Science.gov (United States)

    Yao, Zhibo; Wang, Wenli; Shen, Heping; Zhang, Ye; Luo, Qiang; Yin, Xuewen; Dai, Xuezeng; Li, Jianbao; Lin, Hong

    2017-12-01

    Although the two-step deposition (TSD) method is widely adopted for the high performance perovskite solar cells (PSCs), the CH3NH3PbI3 perovskite crystal growth mechanism during the TSD process and the photo-generated charge recombination dynamics in the mesoporous-TiO2 (mp-TiO2)/CH3NH3PbI3/hole transporting material (HTM) system remains unexploited. Herein, we modified the concentration of PbI2 (C(PbI2)) solution to control the perovskite crystal properties, and observed an abnormal CH3NH3PbI3 grain growth phenomenon atop mesoporous TiO2 film. To illustrate this abnormal grain growth mechanism, we propose that a grain ripening process is taking place during the transformation from PbI2 to CH3NH3PbI3, and discuss the PbI2 nuclei morphology, perovskite grain growing stage, as well as Pb:I atomic ratio difference among CH3NH3PbI3 grains with different morphology. These C(PbI2)-dependent perovskite morphologies resulted in varied charge carrier transfer properties throughout the mp-TiO2/CH3NH3PbI3/HTM hybrid, as illustrated by photoluminescence measurement. Furthermore, the effect of CH3NH3PbI3 morphology on light absorption and interfacial properties is investigated and correlated with the photovoltaic performance of PSCs.

  11. The VOC-Ozone connection: a grassland case study

    Science.gov (United States)

    Wohlfahrt, G.; Hoertnagl, L.; Bamberger, I.; Schnitzhofer, R.; Dunkel, J.; Hammerle, A.; Graus, M.; Hansel, A.

    2009-04-01

    Trophospheric ozone (O3) is formed in the presence of sunlight through the interaction of volatile organic compounds (VOCs) and NOx (NO, NO2). O3 damages plants in several ways, most importantly by reducing net photosynthesis and growth. The extent of this damage depends on the time-integrated absorbed O3 flux (i.e. the dose), which is a function of leaf stomatal conductance and ambient O3 concentration, and further influenced by plant species specific defence mechanisms. VOCs are produced by plants through a variety of pathways and in response to a large number of different driving forces. A large variety of VOCs are emitted by plants in response to stress conditions, including the foliar uptake of O3. Here we present preliminary data from an ongoing study where concurrent measurements of the fluxes of VOCs and O3 are made above a managed mountain grassland in Tyrol/Austria. Fluxes of several different VOCs and O3 are measured by means of the eddy covariance method and a proton transfer reaction mass spectrometer (PTR-MS) and an ozone analyser, respectively. Our findings show that the Methanol (MeOH) flux is correlated with the daily time-integrated O3 uptake by vegetation (integrated daily from sunrise - a surrogate for the O3 dose absorbed and the oxidative stress experienced by plants) - MeOH deposition and emission prevailing at low and high time-integrated O3 uptake rates, respectively. Fluxes of other VOCs were not related to the time-integrated O3 uptake. Integrated over longer time scales (several weeks) no correlation between the O3 uptake and MeOH emissions were found. Our study thus confirms earlier leaf-level studies, who found that MeOH emission increase with O3 dose, at the ecosystems scale. As the reaction with the hydroxyl radical (OH), which is responsible for the destruction of the greenhouse gas methane (CH4), is the major sink of atmospheric MeOH, this process provides a potentially important indirect radiative forcing.

  12. Comparison of HTLV-I Proviral Load in Adult T Cell Leukemia/Lymphoma (ATL), HTLV-I-Associated Myelopathy (HAM-TSP) and Healthy Carriers.

    Science.gov (United States)

    Akbarin, Mohammad Mehdi; Rahimi, Hossein; Hassannia, Tahereh; Shoja Razavi, Ghazaleh; Sabet, Faezeh; Shirdel, Abbas

    2013-03-01

    Human T Lymphocyte Virus Type one (HTLV-I) is a retrovirus that infects about 10-20 million people worldwide. Khorasan province in Iran is an endemic area. The majority of HTLV-I-infected individuals sustain healthy carriers but small proportion of infected population developed two progressive diseases: HAM/TSP and ATL. The proviral load could be a virological marker for disease monitoring, therefore in the present study HTLV-I proviral load has been evaluated in ATL and compared to HAM/TSP and healthy carriers. In this case series study, 47 HTLV-I infected individuals including 13 ATL, 23 HAM/TSP and 11 asymptomatic subjects were studied. Peripheral blood mononuclear cells (PBMCs) were investigated for presence of HTLV-I DNA provirus by PCR using LTR and Tax fragments. Then in infected subjects, HTLV-I proviral load was measured using real time PCR TaqMan method. The average age of patients in ATL was 52±8, in HAM/TSP 45.52±15.17 and in carrier's 38.65±14.9 years which differences were not statistically significant. The analysis of data showed a significant difference in mean WBC among study groups (ATL vs HAM/TSP and carriers P=0.0001). Moreover, mean HTLV-I proviral load was 11967.2 ± 5078, 409 ± 71.3 and 373.6 ± 143.3 in ATL, HAM/TSP and Healthy Carriers, respectively. The highest HTLV-I proviral load was measured in ATL group that had a significant correlation with WBC count (R=0.495, P=0.001). The proviral load variations between study groups was strongly significant (ATL vs carrier P=0.0001; ATL vs HAM/TSP P= 0.0001 and HAM/TSP vs carriers P< 0.05). Conclusion : The present study demonstrated that HTLV-I proviral load was higher in ATL group in comparison with HAM/TSP and healthy carriers. Therefore, HTLV-I proviral load is a prognostic factor for development of HTLV-I associated diseases and can be used as a monitoring marker for the efficiency of therapeutic regime.

  13. Dissociation of NH3 and NH2D by high power CO2 laser radiation

    International Nuclear Information System (INIS)

    Jacobs, R.R.

    1976-08-01

    Multiquantum dissociation of polyatomics using intense CO 2 lasers resulting in isotopic enrichment has been demonstrated for several molecules. In this presentation, the possibility of selective dissociation of NH 3 and NH 2 D by high power laser radiation at 10 μm will be considered. Relevant work performed at the Lawrence Livermore Laboratory and elsewhere will be summarized. In this review, attention will be given to four distinct mechanisms that can play varying degrees of importance in such investigations. Discussion will deal with the usefulness of two-resonant-frequency molecular excitation, the role of buffer gases, and the need to monitor the yields into the ground and excited electronic states of the dissociated fragments

  14. Interfacial electronic structures revealed at the rubrene/CH3NH3PbI3 interface.

    Science.gov (United States)

    Ji, Gengwu; Zheng, Guanhaojie; Zhao, Bin; Song, Fei; Zhang, Xiaonan; Shen, Kongchao; Yang, Yingguo; Xiong, Yimin; Gao, Xingyu; Cao, Liang; Qi, Dong-Chen

    2017-03-01

    The electronic structures of rubrene films deposited on CH 3 NH 3 PbI 3 perovskite have been investigated using in situ ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). It was found that rubrene molecules interacted weakly with the perovskite substrate. Due to charge redistribution at their interface, a downward 'band bending'-like energy shift of ∼0.3 eV and an upward band bending of ∼0.1 eV were identified at the upper rubrene side and the CH 3 NH 3 PbI 3 substrate side, respectively. After the energy level alignment was established at the rubrene/CH 3 NH 3 PbI 3 interface, its highest occupied molecular orbital (HOMO)-valence band maximum (VBM) offset was found to be as low as ∼0.1 eV favoring the hole extraction with its lowest unoccupied molecular orbital (LUMO)-conduction band minimum (CBM) offset as large as ∼1.4 eV effectively blocking the undesired electron transfer from perovskite to rubrene. As a demonstration, simple inverted planar solar cell devices incorporating rubrene and rubrene/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layers (HTLs) were fabricated in this work and yielded a champion power conversion efficiency of 8.76% and 13.52%, respectively. Thus, the present work suggests that a rubrene thin film could serve as a promising hole transport layer for efficient perovskite-based solar cells.

  15. Interfacial Charge-Carrier Trapping in CH3NH3PbI3-Based Heterolayered Structures Revealed by Time-Resolved Photoluminescence Spectroscopy.

    Science.gov (United States)

    Yamada, Yasuhiro; Yamada, Takumi; Shimazaki, Ai; Wakamiya, Atsushi; Kanemitsu, Yoshihiko

    2016-06-02

    The fast-decaying component of photoluminescence (PL) under very weak pulse photoexcitation is dominated by the rapid relaxation of the photoexcited carriers into a small number of carrier-trapping defect states. Here, we report the subnanosecond decay of the PL under excitation weaker than 1 nJ/cm(2) both in CH3NH3PbI3-based heterostructures and bare thin films. The trap-site density at the interface was evaluated on the basis of the fluence-dependent PL decay profiles. It was found that high-density defects determining the PL decay dynamics are formed near the interface between CH3NH3PbI3 and the hole-transporting Spiro-OMeTAD but not at the CH3NH3PbI3/TiO2 interface and the interior regions of CH3NH3PbI3 films. This finding can aid the fabrication of high-quality heterointerfaces, which are required improving the photoconversion efficiency of perovskite-based solar cells.

  16. Reduction of RuVI≡N to RuIII-NH3 by Cysteine in Aqueous Solution.

    Science.gov (United States)

    Wang, Qian; Man, Wai-Lun; Lam, William W Y; Yiu, Shek-Man; Tse, Man-Kit; Lau, Tai-Chu

    2018-05-21

    The reduction of metal nitride to ammonia is a key step in biological and chemical nitrogen fixation. We report herein the facile reduction of a ruthenium(VI) nitrido complex [(L)Ru VI (N)(OH 2 )] + (1, L = N, N'-bis(salicylidene)- o-cyclohexyldiamine dianion) to [(L)Ru III (NH 3 )(OH 2 )] + by l-cysteine (Cys), an ubiquitous biological reductant, in aqueous solution. At pH 1.0-5.3, the reaction has the following stoichiometry: [(L)Ru VI (N)(OH 2 )] + + 3HSCH 2 CH(NH 3 )CO 2 → [(L)Ru III (NH 3 )(OH 2 )] + + 1.5(SCH 2 CH(NH 3 )CO 2 ) 2 . Kinetic studies show that at pH 1 the reaction consists of two phases, while at pH 5 there are three distinct phases. For all phases the rate law is rate = k 2 [1][Cys]. Studies on the effects of acidity indicate that both HSCH 2 CH(NH 3 + )CO 2 - and - SCH 2 CH(NH 3 + )CO 2 - are kinetically active species. At pH 1, the reaction is proposed to go through [(L)Ru IV (NHSCH 2 CHNH 3 CO 2 H)(OH 2 )] 2+ (2a), [(L)Ru III (NH 2 SCH 2 CHNH 3 CO 2 H)(OH 2 )] 2+ (3), and [(L)Ru IV (NH 2 )(OH 2 )] + (4) intermediates. On the other hand, at pH around 5, the proposed intermediates are [(L)Ru IV (NHSCH 2 CHNH 3 CO 2 )(OH 2 )] + (2b) and [(L)Ru IV (NH 2 )(OH 2 )] + (4). The intermediate ruthenium(IV) sulfilamido species, [(L)Ru IV (NHSCH 2 CHNH 3 CO 2 H)(OH 2 )] 2+ (2a) and the final ruthenium(III) ammine species, [(L)Ru III (NH 3 )(MeOH)] + (5) (where H 2 O was replaced by MeOH) have been isolated and characterized by various spectroscopic methods.

  17. Improvement of photovoltaic performance of the inverted planar perovskite solar cells by using CH3NH3PbI3-xBrx films with solvent annealing

    Science.gov (United States)

    Wang, Shan; Zhang, Weijia; Ma, Denghao; Jiang, Zhaoyi; Fan, Zhiqiang; Ma, Qiang; Xi, Yilian

    2018-01-01

    In this paper, the CH3NH3PbI3-xBrx films with various Br-doping contents were successfully prepared by solution processed deposition and followed by annealing process. This method simultaneously modified the morphology and composition of the CH3NH3PbI3 film. The effects of annealing treatment of CH3NH3PbI3-xBrx films under N2 and DMSO conditions on the microstructure of films and photoelectric properties of the solar cells were systematically investigated. The relationship of the component ratio of RBr/I= CH3NH3PbI3-xBrx/CH3NH3PbI3 in the resulting perovskite versus CH3NH3Br concentration also was explored. The results revealed that the CH3NH3PbI3-xBrx films annealed under DMSO exhibited increased grain sizes, enhanced crystallinity, enlarged bandgap and reduced defect density compared with that of the N2 annealing. It also was found that the RBr/I linearly increased in the resulting perovskite with the increased of CH3NH3Br concentration in the methylammonium halide mixture solutions. Furthermore, the photovoltaic performances of devices fabricated using DMSO precursor solvent were worse than that of DMF under N2 annealing atmosphere. When CH3NH3Br concentration was 7.5 mg ml-1, the planar perovskite solar cell based on CH3NH3PbI3-xBrx annealed under DMSO showed the best efficiency of 13.7%.

  18. Room temperature three-photon pumped CH3NH3PbBr3 perovskite microlasers

    Science.gov (United States)

    Gao, Yisheng; Wang, Shuai; Huang, Can; Yi, Ningbo; Wang, Kaiyang; Xiao, Shumin; Song, Qinghai

    2017-03-01

    Hybrid lead halide perovskites have made great strides in next-generation light-harvesting and light emitting devices. Recently, they have also shown great potentials in nonlinear optical materials. Two-photon absorption and two-photon light emission have been thoroughly studied in past two years. However, the three-photon processes are rarely explored, especially for the laser emissions. Here we synthesized high quality CH3NH3PbBr3 perovskite microstructures with solution processed precipitation method and studied their optical properties. When the microstructures are pumped with intense 1240 nm lasers, we have observed clear optical limit effect and the band-to-band photoluminescence at 540 nm. By increasing the pumping density, whispering-gallery-mode based microlasers have been achieved from CH3NH3PbBr3 perovskite microplate and microrod for the first time. This work demonstrates the potentials of hybrid lead halide perovskites in nonlinear photonic devices.

  19. Tunable far infrared laser spectroscopy of van der Waals bonds: Ar-NH sub 3

    Energy Technology Data Exchange (ETDEWEB)

    Gwo, Dz-Hung (Lawrence Berkeley Lab., CA (USA) California Univ., Berkeley, CA (USA). Dept. of Chemistry)

    1989-11-01

    Hyperfine resolved vibration-rotation-tunneling spectra of Ar--NH{sub 3} and (NH{sub 3}){sub 2}, generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar--NH{sub 3}, and the other six belong to (NH{sub 3}){sub 2}. To facilitate the intermolecular vibrational assignment for Ar--NH{sub 3}, a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states. An anomalous vibronically allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar--NH{sub 3} centered at 26.470633(17) cm{sup {minus}1} can correlate only to either the fundamental dimeric stretching band for the A{sub 2} states with the NH{sub 3} inversional quantum number v{sub i} = 1, or the K{sub a} = 0 {l arrow} 0 subband of the lowest internal-rotation-inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require far infrared data and a dynamical model incorporating a potential surface.

  20. An Effective Implementation of K-opt Moves for the Lin-Kernighan TSP Heuristic

    DEFF Research Database (Denmark)

    Helsgaun, Keld

    Local search with k-change neighborhoods, k-opt, is the most widely used heuristic method for the traveling salesman problem (TSP). This report presents an effective implementation of k-opt for the Lin- Kernighan TSP heuristic. The effectiveness of the implementation is demonstrated with extensive...

  1. In situ attenuated total reflection infrared (ATR-IR) study of the adsorption of NO2-, NH2OH, and NH4+ on Pd/Al2O3 and Pt/Al2O3.

    NARCIS (Netherlands)

    Ebbesen, S.D.; Mojet, Barbara; Lefferts, Leonardus

    2008-01-01

    In relation to the heterogeneous hydrogenation of nitrite, adsorption of NO2-, NH4+, and NH2OH from the aqueous phase was examined on Pt/Al2O3, Pd/Al2O3, and Al2O3. None of the investigated inorganic nitrogen compounds adsorb on alumina at conditions presented in this study. NO2-(aq) and NH4+(aq) on

  2. Meteorite impacts on ancient oceans opened up multiple NH3 production pathways.

    Science.gov (United States)

    Shimamura, Kohei; Shimojo, Fuyuki; Nakano, Aiichiro; Tanaka, Shigenori

    2017-05-10

    A recent series of shock experiments by Nakazawa et al. starting in 2005 (e.g. [Nakazawa et al., Earth Planet. Sci. Lett., 2005, 235, 356]) suggested that meteorite impacts on ancient oceans would have yielded a considerable amount of NH 3 to the early Earth from atmospheric N 2 and oceanic H 2 O through reduction by meteoritic iron. To clarify the mechanisms, we imitated the impact events by performing multi-scale shock technique-based ab initio molecular dynamics in the framework of density functional theory in combination with multi-scale shock technique (MSST) simulations. Our previous simulations with impact energies close to that of the experiments revealed picosecond-order rapid NH 3 production during shock compression [Shimamura et al., Sci. Rep., 2016, 6, 38952]. It was also shown that the reduction of N 2 took place with an associative mechanism as seen in the catalysis of nitrogenase enzymes. In this study, we performed an MSST-AIMD simulation to investigate the production by meteorite impacts with higher energies, which are closer to the expected values on the early Earth. It was found that the amount of NH 3 produced further increased. We also found that the increased NH 3 production is due to the emergence of multiple reaction mechanisms at increased impact energies. We elucidated that the reduction of N 2 was not only attributed to the associative mechanism but also to a dissociative mechanism as seen in the Haber-Bosch process and to a mechanism through a hydrazinium ion. The emergence of these multiple production mechanisms capable of providing a large amount of NH 3 would support the suggestions from recent experiments much more strongly than was previously believed, i.e., shock-induced NH 3 production played a key role in the origin of life on Earth.

  3. NH (X 3 summation -, v=1--3) formation and vibrational relaxation in electron-irradiated Ar/N2/H2 mixtures

    International Nuclear Information System (INIS)

    Dodd, J.A.; Lipson, S.J.; Flanagan, D.J.; Blumberg, W.A.M.; Person, J.C.; Green, B.D.

    1991-01-01

    Measurements of the dynamics of NH(X 3 summation - , v =1--3), created in electron-irradiated N 2 /H 2 and Ar/N 2 /H 2 mixtures, have been performed. Time-resolved Fourier spectroscopy was used to observe NH(v→v--1) vibrational fundamental band emission. Time-dependent populations were then determined by spectral fitting. Subsequent kinetic fitting of these populations using a single-quantum relaxation model and a power-law dependence of k v on v yielded the following NH(v =1--3) relaxation rate constants (units of 10 -14 cm 3 s -1 ): k v=1 (N 2 )=1.2±0.5, k v=2 (N 2 )=3.8±1.5, k v=3 (N 2 )=7.5±2.5; k v=1 (Ar)=0.2±0.1, k v=2 (Ar)=0.5±0.2, k v=3 (Ar)=0.8±0.3; k v=1 (H 2 )≤50, k v=2 (H 2 )≤100, k v=3 (H 2 )≤150. In addition, the N 2 /H 2 data provided a measurement of the nascent excited vibrational state distribution resulting from the reaction N( 2 D)+H 2 →NH(X,v)+H. The ratio NH(1):NH(2):NH(3) was found to be 1.0:0.97:0.81 (±0.28 in each value). Comparison of the observed nascent distribution with that of a statistical model suggests that the ratio NH(0):NH(1)=0.47. Using this derived distribution, we find the average product level left-angle v right-angle =1.6, and the fraction of the available product energy in vibration left-angle f v right-angle =0.44

  4. Electron paramagnetic resonance of gamma irradiated (CH3)3NHClO4 and CH3NH3ClO4 single crystals

    International Nuclear Information System (INIS)

    Yavuz, Metin; Koeksal, Fevzi

    1999-01-01

    Gamma irradiation damage centers in (CH 3 ) 3 NHClO 4 and CH 3 NH 3 ClO 4 single crystals have been investigated at room temperature by the electron paramagnetic resonance (EPR) technique. It has been found that γ-irradiation produces the (CH 3 ) 3 N + radical in the first, and NH + 3 and ClO 3 radicals in the second compound. The EPR parameters of the observed radicals have been determined and discussed

  5. A gas sensor array for the simultaneous detection of multiple VOCs.

    Science.gov (United States)

    Zhang, Yumin; Zhao, Jianhong; Du, Tengfei; Zhu, Zhongqi; Zhang, Jin; Liu, Qingju

    2017-05-16

    Air quality around the globe is declining and public health is seriously threatened by indoor air pollution. Typically, indoor air pollutants are composed of a series of volatile organic compounds (VOCs) that are generally harmful to the human body, especially VOCs with low molecular weights (less than 100 Da). Moreover, in some situations, more than one type of VOC is present; thus, a device that can detect one or more VOCs simultaneously would be most beneficial. Here, we synthesized a sensor array with 4 units to detect 4 VOCs: acetone (unit 1), benzene (unit 2), methanol (unit 3) and formaldehyde (unit 4) simultaneously. All units were simultaneously exposed to 2.5 ppm of all four VOCs. The sensitivity of unit 1 was 14.67 for acetone and less than 2.54 for the other VOCs. The sensitivities of units 2, 3 and 4 to benzene, methanol and formaldehyde were 2 18.64, 20.98 and 17.26, respectively, and less than 4.01 for the other VOCs. These results indicated that the sensor array exhibited good selectivity and could be used for the real-time monitoring of indoor air quality. Thus, this device will be useful in situations requiring the simultaneous detection of multiple VOCs.

  6. Nucleotide sequence analysis of HTLV-I isolated from cerebrospinal fluid of a patient with TSP/HAM: comparison to other HTLV-I isolates.

    Science.gov (United States)

    Mukhopadhyaya, R; Sadaie, M R

    1993-02-01

    Human T-cell leukemia virus type I (HTLV-I) has been associated with adult T-cell leukemia/lymphoma and the chronic neurologic disorder tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). To study the genetic structure of the virus associated with TSP/HAM, we have obtained and sequenced a partial genomic clone from an HTLV-I-positive cell line established from cerebrospinal fluid (CSF) of a Jamaican patient with TSP/HAM. This clone consisted of a 4.3-kb viral sequence containing the 5' long terminal repeat (LTR), gag, and N-terminal portion of the pol gene, with an overall 1.3% sequence variation resulting from mostly nucleotide substitutions, as compared to the prototype HTLV-I ATK-1. The gag and pol regions showed only 1.4% and 1.2% nucleotide variations, respectively. However, the U3 region of the LTR showed the highest sequence variation (3.6%), where several changes appear to be common among certain TSP/HAM isolates. Several of these changes reside within the 21-bp boundaries and the Tax-responsive element. It would be important to determine if the observed changes are sufficient to cause neurologic disorders similar to the murine leukemia virus system or simply reflect the divergent pool of HTLV-I from different geographic locations. At this time, we cannot rule out the possibility that the observed changes have either direct or indirect significance for the HTLV-I pathogenesis in TSP/HAM.

  7. Nature of phase transitions in ammonium oxofluorovanadates, a vibrational spectroscopy study of (NH4)3VO2F4 and (NH4)3VOF5.

    Science.gov (United States)

    Gerasimova, Yu V; Oreshonkov, A S; Laptash, N M; Vtyurin, A N; Krylov, A S; Shestakov, N P; Ershov, A A; Kocharova, A G

    2017-04-05

    Two ammonium oxofluorovanadates, (NH 4 ) 3 VO 2 F 4 and (NH 4 ) 3 VOF 5 , have been investigated by temperature-dependent infrared and Raman spectroscopy methods to determine the nature of phase transitions (PT) in these compounds. Dynamics of quasioctahedral groups was simulated within the framework of semi-empirical approach, which justified the cis-conformation of VO 2 F 4 3- (C 2v ) and the C 4v geometry of VOF 5 3- . The observed infrared and Raman spectra of both compounds at room temperature (RT) revealed the presence at least of two crystallographically independent octahedral groups. The first order PT at elevated temperatures is connected with a complete dynamic disordering of these groups with only single octahedral state. At lower temperatures, the octahedra are ordered and several octahedral states appear. This PT is the most pronounced in the case of (NH 4 ) 3 VOF 5 , when at least seven independent VOF 5 3- octahedra are present in the structure below 50K, in accordance with the Raman spectra. Ammonium groups do not take part in PTs at higher and room temperatures but their reorientational motion freezes at lower temperatures. Copyright © 2017. Published by Elsevier B.V.

  8. Improvement of CH3NH3PbI3 thin film using the additive 1,8-diiodooctane for planar heterojunction perovskite cells

    Science.gov (United States)

    Abdulrahman, Solh; Wang, Chunhua; Cao, Chenghao; Zhang, Chujun; Yang, Junliang; Jiang, Li

    2017-10-01

    The thin-film quality is critical for obtaining high-performance perovskite solar cells (PSCs). The additive 1,8-diiodooctane (DIO) was used to control the morphology and structure of CH3NH3PbI3 perovskite thin films, and planar heterojunction (PHJ) PSCs with an architecture of ITO/PEDOT: PSS/CH3NH3PbI3/PCBM/Al was fabricated. It was found that the DIO played an important role on CH3NH3PbI3 thin-film quality and the performance of PHJ-PSCs. With the optimal volume ratio of 2%, the compact and uniform high-quality CH3NH3PbI3 thin films with enhanced crystallinity and less roughness were achieved, resulting in the great improvement of power conversion efficiency (PCE) from about 4.5% to over 9.0%. The research results indicate that the additive DIO is a simple and effective method to produce high-quality perovskite thin film and accordingly develop high-performance PHJ-PSCs.

  9. Reactions of 11C recoil atoms in the systems H2O-NH3, H2O-CH4 and NH3-CH4

    International Nuclear Information System (INIS)

    Nebeling, B.

    1988-11-01

    In this study the chemical reactions of recoil carbon 11 in the binary gas mixtures H 2 O-NH 3 , H 2 O-CH 4 and NH 3 -CH 4 in different mixing ratios as well as in solid H 2 O and in a solid H 2 O-NH 3 mixture were analyzed in dependence of the dose. The analyses were to serve e.g. the simulation of chemical processes caused by solar wind, solar radiation and cosmic radiation in the coma and core of comets. They were to give further information about the role of the most important biogeneous element carbon, i.e. carbon, in the chemical evolution of the solar system. Besides the actual high energy processes resulting in the so-called primary products, also the radiation-chemical changes of the primary products were also observed in a wide range of dosing. The generation of the energetic 11 C atoms took place according to the target composition by the nuclear reactions 14 N(p,α) 11 C, 12 C( 3 He,α) 11 C or the 16 O(p,αpn) 11 C reaction. The identification of the products marked with 11 C was carried out by means of radio gas chromatography or radio liquid chromatography (HPLC). (orig./RB) [de

  10. First principles investigation of half-metallicity and spin gapless semiconductor in CH3NH3Cr x Pb1- x I3 mixed perovskites

    Science.gov (United States)

    Huang, H. M.; Zhu, Z. W.; Zhang, C. K.; He, Z. D.; Luo, S. J.

    2018-04-01

    The structural, electronic and magnetic properties of organic-inorganic hybrid mixed perovskites CH3NH3Cr x Pb1- x I3 ( x = 0.25, 0.50, 0.75, 1.00) in cubic, tetragonal and orthorhombic phases have been investigated by first-principles calculation. The results indicate that the tetragonal CH3NH3Cr0.75Pb0.25I3 is a spin gapless semiconductor with Curie temperature of 663 K estimated using mean field approximation. All other CH3NH3Cr x Pb1- x I3 mixed perovskites are half-metallic ferromagnets together with 100% spin polarization, and their total magnetic moment are 4.00, 8.00, 12.00 and 16.00 µB per unit cell for x = 0.25, 0.50, 0.75 and 1.00, respectively. The effect of , and orientation of organic cation CH3NH3 + on the electronic properties of CH3NH3Cr0.50Pb0.50I3 was investigated. The results show that the CH3NH3 + in different orientations have a slight effect on the lattice constants, the energy gap in minority-spin states, half-metallic gap, local magnetic moment, and Curie temperature.

  11. Orthorhombic fulleride (CH3NH2)K3C60 close to Mott-Hubbard instability: Ab initio study

    Science.gov (United States)

    Potočnik, Anton; Manini, Nicola; Komelj, Matej; Tosatti, Erio; Arčon, Denis

    2012-08-01

    We study the electronic structure and magnetic interactions in methylamine-intercalated orthorhombic alkali-doped fullerene (CH3NH2)K3C60 within the density functional theory. As in the simpler ammonia intercalated compound (NH3)K3C60, the orthorhombic crystal-field anisotropy Δ lifts the t1u triple degeneracy at the Γ point and drives the system deep into the Mott-insulating phase. However, the computed Δ and conduction electron bandwidth W cannot alone account for the abnormally low experimental Néel temperature, TN=11 K, of the methylamine compound, compared to the much higher value TN=40 K of the ammonia one. Significant interactions between CH3NH2 and C603- are responsible for the stabilization of particular fullerene-cage distortions and the ensuing low-spin S=1/2 state. These interactions also seem to affect the magnetic properties, as interfullerene exchange interactions depend on the relative orientation of deformations of neighboring C603- molecules. For the ferro-orientational order of CH3NH2-K+ groups we find an apparent reduced dimensionality in magnetic exchange interactions, which may explain the suppressed Néel temperature. The disorder in exchange interactions caused by orientational disorder of CH3NH2-K+ groups could further contribute to this suppression.

  12. Near room temperature approaches for the preparation of air-stable and crystalline CH{sub 3}NH{sub 3}PbI{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Gujarathi, Yogini D.; Haram, Santosh K., E-mail: haram@chem.unipune.ac.in

    2016-04-15

    This work demonstrates an exotic role of CH{sub 2}Cl{sub 2} in a formation of stable phase of highly crystalline CH{sub 3}NH{sub 3}PbI{sub 3} perovskite, on a bulk scale. In the first method, a partially-reacted product obtained after co-grinding of precursors viz. CH{sub 3}NH{sub 3}I and PbI{sub 2}was sonicated in CH{sub 2}Cl{sub 2} to form pure phase of CH{sub 3}NH{sub 3}PbI{sub 3}. In second method, the precursors in γ-Butyrolactone were treated with CH{sub 2}Cl{sub 2} to form crystalline and phase-pure CH{sub 3}NH{sub 3}PbI{sub 3}. X-ray Diffraction analysis confirmed the formation of stable and highly crystalline tetragonal phase of CH{sub 3}NH{sub 3}PbI{sub 3} perovskite having space group I4cm. Well-defined rhombo-hexagonal dodecahedron crystals were seen in SEM and TEM images. Exceptional air stability of CH{sub 3}NH{sub 3}PbI{sub 3} so forms are attributed to adsorption of CH{sub 2}Cl{sub 2}. Optical band gaps obtained from the diffused reflectance spectra (Kubelka–Munk analysis), matched very well with the one estimated from Cyclic Voltammetry (CV). Valence band and conduction band edge positions estimated from the CV analysis are in good agreement with the one reported from UV photoelectron spectroscopy. Both the samples gave steady state fluorescence at ca. 750 nm with quantum yields in the range 15–35.5%. - Highlights: • A role of CH{sub 2}Cl{sub 2} is brought out in formation of stable CH{sub 3}NH{sub 3}PbI{sub 3} perovskite. • Cyclic voltammetry has been used to estimate the band edge positions. • Excellent fluorescence quantum yield, underlines the minimal structural defects.

  13. Investigation of Structural and Electronic Properties of CH3NH3PbI3 Stabilized by Varying Concentrations of Poly(Methyl Methacrylate (PMMA

    Directory of Open Access Journals (Sweden)

    Celline Awino

    2017-08-01

    Full Text Available Studies have shown that perovskites have a high potential of outdoing silicon based solar cells in terms of solar energy conversion, but their rate of degradation is also high. This study reports on improvement on the stability of CH3NH3PbI3 by passivating it with polymethylmethacrylate (PMMA. Structural and electronic properties of CH3NH3PbI3 stabilized by polymethylmethacrylate (PMMA were investigated by varying concentrations of PMMA in the polymer solutions. Stability tests were performed over a period of time using modulated surface photovoltage (SPV spectroscopy, X-ray diffraction (XRD, and photoluminescence (PL measurements. The XRD patterns confirm the tetragonal structure of the deposited CH3NH3PbI3 for every concentration of PMMA. Furthermore, CH3NH3PbI3 coated with 40 mg/mL of PMMA did not show any impurity phase even after storage in air for 43 days. The Tauc gap (ETauc determined on the basis of the in-phase SPV spectra was found in the range from 1.585 to 1.62 eV for the samples stored during initial days, but shifted towards lower energies as the storage time increased. This can be proposed to be due to different chemical reactions between CH3NH3PbI3/PMMA interfaces and air. PL intensity increased with increasing concentration of PMMA except for the perovskite coated with 40 mg/mL of PMMA. PL quenching in the perovskite coated with 40 mg/mL of PMMA can be interpreted as fast electron transfer towards the substrate in the sample. This study shows that, with an optimum concentration of PMMA coating on CH3NH3PbI3, the lifetime and hence stability on electrical and structural behavior of CH3NH3PbI3 is improved.

  14. Plasma chemistry in an atmospheric pressure Ar/NH3 dielectric barrier discharge

    DEFF Research Database (Denmark)

    Fateev, A.; Leipold, F.; Kusano, Y.

    2005-01-01

    An atmospheric pressure dielectric barrier discharge (DBD) in Ar/NH3 (0.1 - 10%) mixtures with a parallel plate electrode geometry was studied. The plasma was investigated by emission and absorption spectroscopy in the UV spectral range. Discharge current and voltage were measured as well. UV...... of an atmospheric pressure Ar/NH3 DBD are H-2, N-2 and N2H4. The hydrazine (N2H4) concentration in the plasma and in the exhaust gases at various ammonia concentrations and different discharge powers was measured. Thermal N2H4 decomposition into NH2 radicals may be used for NOx reduction processes....

  15. Characterizing the influence of highways on springtime NO2 and NH3 concentrations in regional forest monitoring plots

    International Nuclear Information System (INIS)

    Watmough, Shaun A.; McDonough, Andrew M.; Raney, Shanel M.

    2014-01-01

    Highways are major sources of nitrogen dioxide (NO 2 ) and ammonia (NH 3 ). In this study, springtime NO 2 and NH 3 concentrations were measured at 17 Ontario Forest Biomonitoring Network (OFBN) plots using passive samplers. Average springtime NO 2 concentrations were between 1.3 μg m −3 and 27 μg m −3 , and NH 3 concentrations were between 0.2 μg m −3 and 1.7 μg m −3 , although concentrations measured in May (before leaf out) were typically twice as high as values recorded in June. Average NO 2 concentrations, and to a lesser extent NH 3 , could be predicted by road density at all radii (around the plot) tested (500 m, 1000 m, 1500 m). Springtime NO 2 concentrations were predicted for a further 50 OFBN sites. Normalized plant/lichen N concentrations were positively correlated with estimated springtime NO 2 and NH 3 concentrations. Epiphytic foliose lichen richness decreased with increasing NO 2 and NH 3 , but vascular plant richness was positively related to estimated springtime NO 2 and NH 3 . - Highlights: • Springtime concentrations of NO 2 and NH 3 in Ontario forest plots vary greatly. • Concentrations of NO 2 and NH 3 can be predicted by surrounding road density. • Plant and lichen N concentrations are positively related to predicted NO 2 and NH 3 . • Epiphytic lichen richness in negatively related to NO 2 and NH 3 . • Vascular plant richness is positively related to NO 2 and NH 3 . - “Springtime concentrations of NO 2 and NH 3 at Ontario forest monitoring plots vary greatly and can be predicted by road density surrounding the plot”

  16. Application of ion chemistry to tropospheric VOC measurements

    International Nuclear Information System (INIS)

    Hansel, A.; Wisthaler, A.; Graus, M.; Grabmer, W.

    2002-01-01

    The main interest in tropospheric volatile organic compounds (VOCs) originating from biogenic sources such as forests and anthropogenic sources such as cities is because these reactive trace gases can have a significant impact on levels of oxidants such as ozone (O 3 ) and the hydroxyl radical (OH). The proton-transfer-reaction mass-spectrometry (PTR-MS) technique developed by Werner Lindingers Laboratory, utilizes positive ion chemistry to measure trace neutral concentrations in air. It has been applied in food research, medicine and environmental studies to gain gas phase information about VOCs at parts per trillion (pptv) levels.The real-time method relies on proton transfer reactions between H 3 O + primary ions and VOCs which have a higher proton affinity than water molecules. Organic trace gases such as hydrocarbons, carbonyls, alcohols, acetonitrile, and others can be monitored on-line.Results on tropospheric VOCs measurements in tropical regions and in cities are discussed. (nevyjel)

  17. CO2 Absorption and Magnesium Carbonate Precipitation in MgCl2–NH3NH4Cl Solutions: Implications for Carbon Capture and Storage

    Directory of Open Access Journals (Sweden)

    Chen Zhu

    2017-09-01

    Full Text Available CO2 absorption and carbonate precipitation are the two core processes controlling the reaction rate and path of CO2 mineral sequestration. Whereas previous studies have focused on testing reactive crystallization and precipitation kinetics, much less attention has been paid to absorption, the key process determining the removal efficiency of CO2. In this study, adopting a novel wetted wall column reactor, we systematically explore the rates and mechanisms of carbon transformation from CO2 gas to carbonates in MgCl2–NH3NH4Cl solutions. We find that reactive diffusion in liquid film of the wetted wall column is the rate-limiting step of CO2 absorption when proceeding chiefly through interactions between CO2(aq and NH3(aq. We further quantified the reaction kinetic constant of the CO2–NH3 reaction. Our results indicate that higher initial concentration of NH4Cl ( ≥ 2 mol · L − 1 leads to the precipitation of roguinite [ ( NH 4 2 Mg ( CO 3 2 · 4 H 2 O ], while nesquehonite appears to be the dominant Mg-carbonate without NH4Cl addition. We also noticed dypingite formation via phase transformation in hot water. This study provides new insight into the reaction kinetics of CO2 mineral carbonation that indicates the potential of this technique for future application to industrial-scale CO2 sequestration.

  18. Targeting Neutrophil Protease-Mediated Degradation of Tsp-1 to Induce Metastatic Dormancy

    Science.gov (United States)

    2017-10-01

    AWARD NUMBER: W81XWH-16-1-0615 TITLE: Targeting Neutrophil Protease-Mediated Degradation of Tsp-1 to Induce Metastatic Dormancy PRINCIPAL...29 Sep 2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Targeting Neutrophil Protease-Mediated Degradation of Tsp-1 to Induce Metastatic Dormancy...infection or cigarette smoke enhanced pulmonary metastasis from breast cancer in humans and mice. Similarly, autoimmune arthritis, characterized by

  19. Heterolytic cleavage of ammonia N-H bond by bifunctional activation in silica-grafted single site Ta(V) imido amido surface complex. Importance of the outer sphere NH3 assistance

    KAUST Repository

    Gouré, Eric

    2011-01-01

    Ammonia N-H bond is cleaved at room temperature by the silica-supported tantalum imido amido complex [(≡SiO)2Ta(NH)(-NH2)], 2, if excess ammonia is present, but requires 150 °C to achieve the same reaction if only one equivalent NH3 is added to 2. MAS solid-state 15N NMR and in situ IR spectroscopic studies of the reaction of either 15N or 2H labeled ammonia with 2 show that initial coordination of the ammonia is followed by scrambling of either 15N or 2H among ammonia, amido and imido groups. Density functional theory (DFT) calculations with a cluster model [{(μ-O)[(H3SiO) 2SiO]2}Ta(NH)(-NH2)(NH3)], 2 q·NH3, show that the intramolecular H transfer from Ta-NH2 to TaNH is ruled out, but the H transfers from the coordinated ammonia to the amido and imido groups have accessible energy barriers. The energy barrier for the ammonia N-H activation by the Ta-amido group is energetically preferred relative to the Ta-imido group. The importance of excess NH3 for getting full isotope scrambling is rationalized by an outer sphere assistance of ammonia acting as proton transfer agent, which equalizes the energy barriers for H transfer from coordinated ammonia to the amido and imido groups. In contrast, additional coordinated ammonia does not favor significantly the H transfer. These results rationalize the experimental conditions used. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011.

  20. Room temperature solution processed low dimensional CH3NH3PbI3 NIR detector

    Science.gov (United States)

    Besra, N.; Paul, T.; Sarkar, P. K.; Thakur, S.; Sarkar, S.; Das, A.; Chanda, K.; Sardar, K.; Chattopadhyay, K. K.

    2018-05-01

    Metal halide perovskites have recently drawn immense research interests among the worldwide scientific community due to their excellent light harvesting capabilities and above all, cost effectiveness. These new class of materials have already been used as efficient optoelectronic devices e.g. solar cells, photo detectors, etc. Here in this work, room temperature NIR (near infra red) response of organic-inorganic lead halide perovskite CH3NH3PbI3 (Methylammonium lead tri iodide) nanorods has been studied. A very simple solution process technique has been adopted to synthesize CH3NH3PbI3 nanostructures at room temperature. The NIR exposure upon the sample resulted in a considerable hike in its dark current with very good responsivity (0.37 mA/W). Along with that, a good on-off ratio (41.8) was also obtained when the sample was treated under a pulsed NIR exposure with operating voltage of 2 V. The specific detectivity of the device came in the order of 1010 Jone.

  1. mer-Triammine trifluorido vanadium(III), mer-[VF{sub 3}(NH{sub 3}){sub 3}]. Synthesis and crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Woidy, Patrick [Technische Univ. Muenchen, Garching (Germany). Zentrale Technisch-Wissenschaftliche Betriebseinheit Radiochemie Muenchen RCM; Kraus, Florian [Marburg Univ. (Germany). Anorganische und Fluorchemie

    2015-07-01

    Vanadium trifluoride reacts with dry liquid ammonia under the formation of lilac plate-shaped crystals of mer-triammine trifluorido vanadium(III) (1), mer-[VF{sub 3}(NH{sub 3}){sub 3}]. Single-crystal X-ray analysis was carried out at low temperature to elucidate the structure. The compound crystallizes in the monoclinic space group P2{sup 1}/c with a = 5.7284(4), b = 9.2033(5), c = 10.5271(6) Aa, beta = 91.795(6)°, and V = 554.72(6) Aa{sup 3} at 123 K with Z = 4. The discrete [VF{sub 3}(NH{sub 3}){sub 3}] molecules are interconnected by hydrogen bonds.

  2. Synthesis and structure of [(NH2)2CSSC(NH2)2]2[OsBr6]Br2 . 3H2O

    International Nuclear Information System (INIS)

    Rudnitskaya, O. V.; Kultyshkina, E. K.; Stash, A. I.; Glukhova, A. A.; Venskovskii, N. U.

    2008-01-01

    The complex [(NH 2 ) 2 CSSC(NH 2 ) 2 ] 2 [OsBr 6 ]Br 2 . 3H 2 O is synthesized by the reaction of K 2 OsBr 6 with thiocarbamide in concentrated HBr and characterized using electronic absorption and IR absorption spectroscopy. Its crystal structure is determined by X-ray diffraction. The crystals are orthorhombic, a = 11.730(2) A, b = 14.052(3) A, c = 16.994(3) A, space group Cmcm, and Z = 4. The [OsBr 6 ] 2- anionic complex has an octahedral structure. The Os-Br distances fall in the range 2.483-2.490 A. The α,α'-dithiobisformamidinium cation is a product of the oxidation of thiocarbamide. The S-S and C-S distances are 2.016 and 1.784 A, respectively. The H 2 O molecules, Br - ions, and NH 2 groups of the cation are linked by hydrogen bonds.

  3. Porphyrin molecules boost the sensitivity of epitaxial graphene for NH3 detection

    Science.gov (United States)

    Iezhokin, I.; den Boer, D.; Offermans, P.; Ridene, M.; Elemans, J. A. A. W.; Adriaans, G. P.; Flipse, C. F. J.

    2017-02-01

    The sensitivity of quasi-free standing epitaxial graphene for NH3 detection is strongly enhanced by chemical functionalization with cobalt porphyrins resulting in a detection limit well below 100 ppb. Hybridization between NH3 and cobalt porphyrins induces a charge transfer to graphene and results in a shift of the graphene Fermi-level as detected by Hall measurements and theoretically explained by electronic structure calculations.

  4. Isotopically decoupled vibrational spectra and proton exchange rates for crystalline NH3 and ammonia hydrate

    Science.gov (United States)

    Thornton, Cynthia; Khatkale, M. S.; Devlin, J. Paul

    1981-12-01

    Codeposits of NH3 with ND3 or D2O have been prepared at liquid nitrogen temperatures in the absence of proton exchange. Vibrational data for the anhydrous cubic crystalline ammonia, containing isolated NH3 or ND3, confirm that, relative to water ice, intermolecular coupling in ammonia ice exerts a relatively minor influence on the infrared and Raman spectra. Nevertheless, sizeable decoupling shifts, particularly for ν1, have been observed and attributed to a combination of factors including correlation field and Fermi resonance effects. The Raman polarization data has also affirmed long standing assignments of ν1 and ν3 for ammonia ice. Warming of the ammonia thin films resulted in limited isotopic scrambling at 130 K, apparently possible only through the agency of trace concentrations of water. The vibrational coupling pattern for the resultant NHD2 and NH2D molecules suggest that proton (deuteron) migration away from the exchange centers is impossible at temperatures up to 150 K. By contrast, isotopic scrambling was rapid and complete at 140 K for amorphous ammonia hydrate films (˜35% NH3, ˜65% D2O) which were also prepared without exchange at ˜90 K. The proton (deuteron) exchange rate is much greater for the amorphous ammonia hydrate at 140 K than for pure water ice. Such exchange requires both ion-pair defect formation and proton mobility. Since the NH3 suppresses the H3O+ concentration via formation of NH+4, a suppression the likes of which has been shown to stop proton exchange in water ice, the evidence strongly suggests that NH4+ in ammonia, like H3O+ in water, is an effective proton transfer agent, probably acting through a tunneling mechanism (i.e., H3N+-HṡṡṡNH3→H3NṡṡṡH-N+H3 etc.) to render the proton mobile in the ammonia hydrate. This mobility combined with the greater NH4+ concentration, relative to the H3O+ concentration in H2O ice Ic, results in isotopic scrambling at the reduced temperature.

  5. Characteristics of Ambient Volatile Organic Compounds (VOCs Measured in Shanghai, China

    Directory of Open Access Journals (Sweden)

    Guang-Qiang Zhou

    2010-08-01

    Full Text Available To better understand the characteristics of ambient abundance of volatile organic compounds (VOCs in Shanghai, one of the biggest metropolis of China, VOCs were measured with a gas chromatography system equipped with a mass-selective detector (GC/MSD from July 2006 to February 2010. An intensive measurement campaign was conducted (eight samples per day with a 3 hour interval during May 2009. The comparison of ambient VOCs collected in different regions of Shanghai shows that the concentrations are slightly higher in the busy commercial area (28.9 ppbv at Xujiaui than in the urban administrative area (24.3 ppbv at Pudong. However, during the intensive measurement period, the concentrations in the large steel industrial area (28.7 ppbv at Baoshan were much higher than in the urban administrative area (18 ppbv at Pudong, especially for alkanes, alkenes, and toluene. The seasonal variations of ambient VOC concentrations measured at the Xujiahui sampling site indicate that the VOC concentrations are significantly affected by meteorological conditions (such as wind direction and precipitation. In addition, although alkanes are the most abundant VOCs at the Xujiahui measurement site, the most important VOCs contributing to ozone formation potential (OFP are aromatics, accounting for 57% of the total OFP. The diurnal variations of VOC concentrations show that VOC concentrations are higher on weekdays than in weekends at the Xujiahui sampling site, suggesting that traffic condition and human activities have important impacts on VOC emissions in Shanghai. The evidence also shows that the major sources of isoprene are mainly resulted from gasoline evaporation at a particular time (06:00–09:00 in the busy commercial area. The results gained from this study provide useful information for better understanding the characteristics of ambient VOCs and the sources of VOCs in Shanghai.

  6. Characteristics of Ambient Volatile Organic Compounds (VOCs) Measured in Shanghai, China

    Science.gov (United States)

    Cai, Chang-Jie; Geng, Fu-Hai; Tie, Xue-Xi; Yu, Qiong; Peng, Li; Zhou, Guang-Qiang

    2010-01-01

    To better understand the characteristics of ambient abundance of volatile organic compounds (VOCs) in Shanghai, one of the biggest metropolis of China, VOCs were measured with a gas chromatography system equipped with a mass-selective detector (GC/MSD) from July 2006 to February 2010. An intensive measurement campaign was conducted (eight samples per day with a 3 hour interval) during May 2009. The comparison of ambient VOCs collected in different regions of Shanghai shows that the concentrations are slightly higher in the busy commercial area (28.9 ppbv at Xujiaui) than in the urban administrative area (24.3 ppbv at Pudong). However, during the intensive measurement period, the concentrations in the large steel industrial area (28.7 ppbv at Baoshan) were much higher than in the urban administrative area (18 ppbv at Pudong), especially for alkanes, alkenes, and toluene. The seasonal variations of ambient VOC concentrations measured at the Xujiahui sampling site indicate that the VOC concentrations are significantly affected by meteorological conditions (such as wind direction and precipitation). In addition, although alkanes are the most abundant VOCs at the Xujiahui measurement site, the most important VOCs contributing to ozone formation potential (OFP) are aromatics, accounting for 57% of the total OFP. The diurnal variations of VOC concentrations show that VOC concentrations are higher on weekdays than in weekends at the Xujiahui sampling site, suggesting that traffic condition and human activities have important impacts on VOC emissions in Shanghai. The evidence also shows that the major sources of isoprene are mainly resulted from gasoline evaporation at a particular time (06:00–09:00) in the busy commercial area. The results gained from this study provide useful information for better understanding the characteristics of ambient VOCs and the sources of VOCs in Shanghai. PMID:22163629

  7. Mobile telephones: a comparison of radiated power between 3G VoIP calls and 3G VoCS calls.

    Science.gov (United States)

    Jovanovic, Dragan; Bragard, Guillaume; Picard, Dominique; Chauvin, Sébastien

    2015-01-01

    The purpose of this study is to assess the mean RF power radiated by mobile telephones during voice calls in 3G VoIP (Voice over Internet Protocol) using an application well known to mobile Internet users, and to compare it with the mean power radiated during voice calls in 3G VoCS (Voice over Circuit Switch) on a traditional network. Knowing that the specific absorption rate (SAR) is proportional to the mean radiated power, the user's exposure could be clearly identified at the same time. Three 3G (High Speed Packet Access) smartphones from three different manufacturers, all dual-band for GSM (900 MHz, 1800 MHz) and dual-band for UMTS (900 MHz, 1950 MHz), were used between 28 July and 04 August 2011 in Paris (France) to make 220 two-minute calls on a mobile telephone network with national coverage. The places where the calls were made were selected in such a way as to describe the whole range of usage situations of the mobile telephone. The measuring equipment, called "SYRPOM", recorded the radiation power levels and the frequency bands used during the calls with a sampling rate of 20,000 per second. In the framework of this study, the mean normalised power radiated by a telephone in 3G VoIP calls was evaluated at 0.75% maximum power of the smartphone, compared with 0.22% in 3G VoCS calls. The very low average power levels associated with use of 3G devices with VoIP or VoCS support the view that RF exposure resulting from their use is far from exceeding the basic restrictions of current exposure limits in terms of SAR.

  8. Effects of CuBr addition to CH3NH3PbI3(Cl) perovskite photovoltaic devices

    Science.gov (United States)

    Oku, Takeo; Ohishi, Yuya; Tanaka, Hiroki

    2018-01-01

    Effects of CuBr addition to perovskite CH3NH3PbI3(Cl) precursor solutions on photovoltaic properties were investigated. The CH3NH3Pb(Cu)I3(Cl,Br)-based photovoltaic devices were fabricated by a spin-coating technique, and the microstructures of the devices were investigated by X-ray diffraction, optical microscopy and scanning electron microscopy. Current density-voltage characteristics were improved by a small amount of CuBr addition, which resulted in improvement of the conversion efficiencies of the devices. The structure analysis showed decrease of unit cell volume and increase of Cu/Br composition by the CuBr addition, which would indicate the Cu/Br substitution at the Pb/I sites in the perovskite crystal, respectively.

  9. Modeling VOC transport in simulated waste drums

    International Nuclear Information System (INIS)

    Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Hotz, N.J.; Connolly, M.J.

    1993-06-01

    A volatile organic compound (VOC) transport model has been developed to describe unsteady-state VOC permeation and diffusion within a waste drum. Model equations account for three primary mechanisms for VOC transport from a void volume within the drum. These mechanisms are VOC permeation across a polymer boundary, VOC diffusion across an opening in a volume boundary, and VOC solubilization in a polymer boundary. A series of lab-scale experiments was performed in which the VOC concentration was measured in simulated waste drums under different conditions. A lab-scale simulated waste drum consisted of a sized-down 55-gal metal drum containing a modified rigid polyethylene drum liner. Four polyethylene bags were sealed inside a large polyethylene bag, supported by a wire cage, and placed inside the drum liner. The small bags were filled with VOC-air gas mixture and the VOC concentration was measured throughout the drum over a period of time. Test variables included the type of VOC-air gas mixtures introduced into the small bags, the small bag closure type, and the presence or absence of a variable external heat source. Model results were calculated for those trials where the VOC permeability had been measured. Permeabilities for five VOCs [methylene chloride, 1,1,2-trichloro-1,2,2-trifluoroethane (Freon-113), 1,1,1-trichloroethane, carbon tetrachloride, and trichloroethylene] were measured across a polyethylene bag. Comparison of model and experimental results of VOC concentration as a function of time indicate that model accurately accounts for significant VOC transport mechanisms in a lab-scale waste drum

  10. The motor evoked potential in AIDS and HAM/TSP: state of the evidence.

    Science.gov (United States)

    Leon-Sarmiento, Fidias E; Elfakhani, Mohamed; Boutros, Nash N

    2009-12-01

    We aimed to better understand the involvement of the corticospinal tract, assessed by non-invasive transcranial stimulation, in order to determine the actual involvement of the motor system in patients with HAM/TSP and AIDS. An exhaustive MEDLINE search for the period of 1985 to 2008 for all articles cross-referenced for 'HTLV-I, HTLV-II, HTLV-III and HIV, HIV1, HIV2, evoked potential, motor evoked potential, high voltage electrical stimulation, transcranial magnetic stimulation, magnetic stimulation, corticomotor physiology, motor pathways, acquired immunodeficiency syndrome, AIDS, SIDA, tropical spastic paraparesis, HTLV-I-associated myelopathy, HAM, TSP, and HAM/TSP' were selected and analysed. Eighteen papers published in English, Spanish, Portuguese, French and Japanese were identified. Only the central motor conduction time has been analyzed in seropositive patients to human retroviruses. The investigations done on HAM/TSP support the involvement of the pyramidal tract mainly at lower levels, following a centripetal pattern; in AIDS, such an involvement seems to be more prominent at brain levels following a centrifugal pattern. The central motor conduction time abnormalities and involvement differences of the corticospinal tract of patients with AIDS and HAM/TSP dissected here would allow to re-orient early neurorehabilitation measures in these retroviruses-associated neurodegenerative disorders. Besides this, more sophisticated and sensitive non-invasive corticospinal stimulation measures that detect early changes in thalamocortical-basal ganglia circuitry will be needed in both clinically established as well as asymptomatic patients at times when the fastest corticospinal fibers remain uninvolved.

  11. Homogeneous Emission Line Broadening in the Organo Lead Halide Perovskite CH3NH3PbI3-xClx.

    Science.gov (United States)

    Wehrenfennig, Christian; Liu, Mingzhen; Snaith, Henry J; Johnston, Michael B; Herz, Laura M

    2014-04-17

    The organic-inorganic hybrid perovskites methylammonium lead iodide (CH3NH3PbI3) and the partially chlorine-substituted mixed halide CH3NH3PbI3-xClx emit strong and broad photoluminescence (PL) around their band gap energy of ∼1.6 eV. However, the nature of the radiative decay channels behind the observed emission and, in particular, the spectral broadening mechanisms are still unclear. Here we investigate these processes for high-quality vapor-deposited films of CH3NH3PbI3-xClx using time- and excitation-energy dependent photoluminescence spectroscopy. We show that the PL spectrum is homogenously broadened with a line width of 103 meV most likely as a consequence of phonon coupling effects. Further analysis reveals that defects or trap states play a minor role in radiative decay channels. In terms of possible lasing applications, the emission spectrum of the perovskite is sufficiently broad to have potential for amplification of light pulses below 100 fs pulse duration.

  12. Kinetics of gas to particle conversion in the NH/sub 3/-Chl system

    Energy Technology Data Exchange (ETDEWEB)

    Luria, M; Cohen, B

    1980-01-01

    Particle formation in the reaction of NH/sub 3/ and Chl under 1 atm of N/sub 2/ and at 25/sup 0/C was studied in a flow reactor. The critical concentration below which NO particle can be formed was found to be 3.5 x 10/sup +14/ molecule/CM/sup 3/ for (NH/sub 3/)=(HCl). Above this concentration, gas-particle conversion percentage increases rapidly to approach 100%.

  13. Characteristics of 1 year of observational data of VOCs, NOx and O3 at a suburban site in Guangzhou, China

    Science.gov (United States)

    Zou, Y.; Deng, X. J.; Zhu, D.; Gong, D. C.; Wang, H.; Li, F.; Tan, H. B.; Deng, T.; Mai, B. R.; Liu, X. T.; Wang, B. G.

    2015-06-01

    Guangzhou, one of China's megacities, is beset with frequent occurrence of high-concentration ozone events. In this study, online instruments were used to simultaneously monitor ozone, nitrogen oxides (NOx) and volatile organic compounds (VOCs) at GPACS (the Guangzhou Panyu Atmospheric Composition Station) of the China Meteorological Administration, from June 2011 to May 2012, in order to determine their characteristics, the effect of VOCs on ozone photochemical production and the relationship between VOC / NOx ratio and ozone formation. The results showed that during the observation period, the seasonal variation of ozone concentration was lower in spring and winter compared to summer and autumn, which is opposite that for VOCs and NOx. In terms of VOCs, aromatics had the largest ozone formation potential, among which toluene, xylenes, ethylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene were the most important species, with a total contribution of about 44%. As the VOC / NOx ratios were very high during high-concentration ozone events that occur all year round, we speculate ozone production was likely to be NOx-limited regime (12:00-16:00 LT) in Guangzhou. Further investigation based on numerical models is needed in the future to obtain more detailed and robust conclusions.

  14. First detection of ammonia (NH3 in the Asian summer monsoon upper troposphere

    Directory of Open Access Journals (Sweden)

    M. Höpfner

    2016-11-01

    Full Text Available Ammonia (NH3 has been detected in the upper troposphere by the analysis of averaged MIPAS (Michelson Interferometer for Passive Atmospheric Sounding infrared limb-emission spectra. We have found enhanced amounts of NH3 within the region of the Asian summer monsoon at 12–15 km altitude. Three-monthly, 10° longitude  ×  10° latitude average profiles reaching maximum mixing ratios of around 30 pptv in this altitude range have been retrieved, with a vertical resolution of 3–8 km and estimated errors of about 5 pptv. These observations show that loss processes during transport from the boundary layer to the upper troposphere within the Asian monsoon do not deplete the air entirely of NH3. Thus, ammonia might contribute to the so-called Asian tropopause aerosol layer by the formation of ammonium aerosol particles. On a global scale, outside the monsoon area and during different seasons, we could not detect enhanced values of NH3 above the actual detection limit of about 3–5 pptv. This upper bound helps to constrain global model simulations.

  15. Room temperature ammonia and VOC sensing properties of CuO nanorods

    International Nuclear Information System (INIS)

    Bhuvaneshwari, S.; Gopalakrishnan, N.

    2016-01-01

    Here, we report a NH 3 and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

  16. Room temperature ammonia and VOC sensing properties of CuO nanorods

    Science.gov (United States)

    Bhuvaneshwari, S.; Gopalakrishnan, N.

    2016-05-01

    Here, we report a NH3 and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

  17. Room temperature ammonia and VOC sensing properties of CuO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Bhuvaneshwari, S.; Gopalakrishnan, N., E-mail: ngk@nitt.edu [Thin film laboratory, National Institute of Technology, Tiruchirappalli-620015 (India)

    2016-05-23

    Here, we report a NH{sub 3} and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

  18. CH3NH3I treatment temperature of 70 °C in low-pressure vapor-assisted deposition for mesoscopic perovskite solar cells

    Science.gov (United States)

    Jin, Wenbin; Zou, Xiaoping; Bai, Xiao; Yang, Ying; Chen, Dan

    2018-01-01

    Herein, we report a modified vapor-assisted deposition method to fabricate CH3NH3PbI3 film at 70 °C in a vacuum drying oven. The modified method has excellent operability and expandability in preparing perovskite solar cells. The CH3NH3I treatment temperature is 130 °C or 150 °C in conventional method, but we reduced the temperature to 70 °C in the modified vapor-assisted method. Meanwhile, the quality of CH3NH3PbI3 films prepared via the modified method is superior to that of CH3NH3PbI3 films of solution-processed method.

  19. Electron motion in high-pressure polar gases: NH3

    International Nuclear Information System (INIS)

    Christophorou, L.G.; Carter, J.G.; Maxey, D.V.

    1982-01-01

    Drift velocities w for slow electrons in NH 3 vapor have been measured and are reported as a function of the density-reduced electric field E/N ( -17 V cm 2 ), density N (2.43--292 x 10 18 molecule cm -3 ), and temperature T (300--650 K). The w decreases with increasing N considerably and this decrease varies with T; for a fixed N it is higher the lower the T. Use is made of the T- and N-dependence of w to assess the role of the various processes which delay the electron drift. The density range above approx.2.5 x 10 19 molecules cm -3 seems (anionic) electron state. The number density N/sub L/ at which complete electron localization occurs, has been estimated at various T. At T = 300 K, N/sub L/approx. =3.3 x 10 20 molecule cm -3 or approx.0.01 g cm 3 . Estimates have also been made of the binding energy of the electron to the trapping species (possibly NH 3 clusters) which, depending on T, range from 0.11 to 0.15 eV

  20. Room temperature atomic layer deposited Al2O3 on CH3NH3PbI3 characterized by synchrotron-based X-ray photoelectron spectroscopy

    Science.gov (United States)

    Kot, Małgorzata; Das, Chittaranjan; Henkel, Karsten; Wojciechowski, Konrad; Snaith, Henry J.; Schmeisser, Dieter

    2017-11-01

    An ultrathin Al2O3 film deposited on methylammonium lead triiodide (CH3NH3PbI3) perovskite has the capability to suppress the carrier recombination process and improve the perovskite solar cells efficiency and stability. However, annealing at temperatures higher than 85 °C degrades the CH3NH3PbI3 perovskite film. The X-ray photoelectron spectroscopy study performed in this work indicates that it is possible to grow Al2O3 by atomic layer deposition on the perovskite at room temperature, however, besides pure Al2O3 some OH groups are found and the creation of lead and iodine oxides at the Al2O3/CH3NH3PbI3 interface takes place.

  1. 13N-NH3 PET dynamic imaging in the diagnosis of hypopituitarism: preliminary result

    International Nuclear Information System (INIS)

    Zhang Xiangsong; He Zuoxiang; Tang Anwu; Qiao Suixian

    2004-01-01

    Objective: To evaluate the feasibility of diagnosing hypopituitarism with 13N-NH3 PET dynamic imaging. Methods: Eight volunteers (2 male, 6 female, age from 23 to 53 years old) for control and 7 patients (6 female, 20-42 years old, 1 male, 21 year old) were enrolled in this study. 13N-NH3 PET dynamic imaging was performed under 3-D acquisition on the ECAT HR+ PET scanner (Siemens/CTI) with 5-minute transmission scan. The emission protocol was a 20-minute dynamic scan (10s x 12, 30s x 6, 900s x 1) triggered simultaneously with a bolus injection of 444 to 592 MBq of 13N-NH3. The radioactivity - time curves of pituitary and internal carotid artery were generated by setting regions of interest (ROIs) on the transaxial planes of the frames of 13N-NH3 PET sequences. The first-pass uptake rate of 13N-NH3 (R) and standard uptake, rate (SUV) in pituitary on the last frame were calculated. Results: In control studies, the radioactivity in pituitary demonstrated within 10 seconds after the internal carotid artery showed up, and the pituitary highly uptake 13N-NH3, the size of pituitary was (1.07±0.17) cm x (1.09±0.15) cm x (1.14 ± 0.17) cm, SUV was 3.84 ± 1.75, R was 0.75 ± 0.13. In hypopituitarism studies, the radioactivity in pituitary showed up slowly, the pituitary did not show up in two cases with serious hypopituitarism, the size of pituitary was (0.82±0.07) cm x (0.81±0.05) cm x(0.91±0.07) cm, SUV was 1.25±0.08, R was 0.35±0.09. Conclusion: 13N-NH3 PET dynamic imaging is valuable in the diagnosis of hypopituitarism. (authors)

  2. 41 CFR 102-117.280 - What aspects of the TSP's performance are important to measure?

    Science.gov (United States)

    2010-07-01

    ...'s performance are important to measure? 102-117.280 Section 102-117.280 Public Contracts and... § 102-117.280 What aspects of the TSP's performance are important to measure? Important TSP performance...) Percentage of customer satisfaction reports on carrier performance. ...

  3. DNA Vaccine Encoding the Chimeric Form of Schistosoma mansoni Sm-TSP2 and Sm29 Confers Partial Protection against Challenge Infection.

    Directory of Open Access Journals (Sweden)

    Natan Raimundo Gonçalves de Assis

    Full Text Available Schistosomiasis is an important parasitic disease worldwide that affects more than 207 million people in 76 countries and causes approximately 250,000 deaths per year. The best long-term strategy to control schistosomiasis is through immunization combined with drug treatment. Due to the ability of DNA vaccines to generate humoral and cellular immune responses, such vaccines are considered a promising approach against schistosomiasis. Sm29 and tetraspanin-2 (Sm-TSP2 are two proteins that are located in the S. mansoni tegument of adult worms and schistosomula and induce high levels of protection through recombinant protein immunization. In this study, we transfected BHK-21 cells with plasmids encoding Sm29, Sm-TSP2 or a chimera containing both genes. Using RT-PCR analysis and western blot, we confirmed that the DNA vaccine constructs were transcribed and translated, respectively, in BHK-21 cells. After immunization of mice, we evaluated the reduction in worm burden. We observed worm burden reductions of 17-22%, 22%, 31-32% and 24-32% in animals immunized with the pUMVC3/Sm29, pUMVC3/SmTSP-2, pUMVC3/Chimera and pUMVC3/Sm29 + pUMVC3/SmTSP-2 plasmids, respectively. We evaluated the humoral response elicited by DNA vaccines, and animals immunized with pUMVC3/Sm29 and pUMVC3/Sm29 + pUMVC3/SmTSP-2 showed higher titers of anti-Sm29 antibodies. The cytokine profile produced by the spleen cells of immunized mice was then evaluated. We observed higher production of Th1 cytokines, such as TNF-α and IFN-γ, in vaccinated mice and no significant production of IL-4 and IL-5. The DNA vaccines tested in this study showed the ability to generate a protective immune response against schistosomiasis, probably through the production of Th1 cytokines. However, future strategies aiming to optimize the protective response induced by a chimeric DNA construct need to be developed.

  4. DNA Vaccine Encoding the Chimeric Form of Schistosoma mansoni Sm-TSP2 and Sm29 Confers Partial Protection against Challenge Infection

    Science.gov (United States)

    Gonçalves de Assis, Natan Raimundo; Batistoni de Morais, Suellen; Figueiredo, Bárbara Castro Pimentel; Ricci, Natasha Delaqua; de Almeida, Leonardo Augusto; da Silva Pinheiro, Carina; Martins, Vicente de Paulo; Oliveira, Sergio Costa

    2015-01-01

    Schistosomiasis is an important parasitic disease worldwide that affects more than 207 million people in 76 countries and causes approximately 250,000 deaths per year. The best long-term strategy to control schistosomiasis is through immunization combined with drug treatment. Due to the ability of DNA vaccines to generate humoral and cellular immune responses, such vaccines are considered a promising approach against schistosomiasis. Sm29 and tetraspanin-2 (Sm-TSP2) are two proteins that are located in the S. mansoni tegument of adult worms and schistosomula and induce high levels of protection through recombinant protein immunization. In this study, we transfected BHK-21 cells with plasmids encoding Sm29, Sm-TSP2 or a chimera containing both genes. Using RT-PCR analysis and western blot, we confirmed that the DNA vaccine constructs were transcribed and translated, respectively, in BHK-21 cells. After immunization of mice, we evaluated the reduction in worm burden. We observed worm burden reductions of 17-22%, 22%, 31-32% and 24-32% in animals immunized with the pUMVC3/Sm29, pUMVC3/SmTSP-2, pUMVC3/Chimera and pUMVC3/Sm29 + pUMVC3/SmTSP-2 plasmids, respectively. We evaluated the humoral response elicited by DNA vaccines, and animals immunized with pUMVC3/Sm29 and pUMVC3/Sm29 + pUMVC3/SmTSP-2 showed higher titers of anti-Sm29 antibodies. The cytokine profile produced by the spleen cells of immunized mice was then evaluated. We observed higher production of Th1 cytokines, such as TNF-α and IFN-γ, in vaccinated mice and no significant production of IL-4 and IL-5. The DNA vaccines tested in this study showed the ability to generate a protective immune response against schistosomiasis, probably through the production of Th1 cytokines. However, future strategies aiming to optimize the protective response induced by a chimeric DNA construct need to be developed. PMID:25942636

  5. Polarisation properties of irradiated ammonia (NH3 and ND3) at 1 K and 25 kG

    International Nuclear Information System (INIS)

    Riechert, H.

    1982-11-01

    Dynamic Nuclear Polarisation (DNP) of irradiated ammonia was examined in some detail at 1 K and 25 kG. In continuation of earlier studies conducted in Bonn, it was attempted to gain information about the prevailing mechanism of DNP in this material. Therefore the frequency dependence of DNP in NH 3 , of deuterons and unsubstituted protons in ND 3 , as well as the polarising time tau and the relaxation time T 1 in NH 3 were measured. Also the shape of the deuteron polarisation signal observed in ND 3 is discussed. The polarisation measurements in ND 3 rule out the equal spin temperature (EST) behaviour of proton and deuteron DNP that is observed in most of the currently used target materials. It is attempted to explain the observations with a differential solid state effect model. Results of calculations for NH 3 and ND 3 incorporating the measured EPR-spectra are presented. (orig.)

  6. Projections of NH3 emissions from manure generated by livestock production in China to 2030 under six mitigation scenarios.

    Science.gov (United States)

    Xu, Peng; Koloutsou-Vakakis, Sotiria; Rood, Mark J; Luan, Shengji

    2017-12-31

    China's rapid urbanization, large population, and increasing consumption of calorie-and meat-intensive diets, have resulted in China becoming the world's largest source of ammonia (NH 3 ) emissions from livestock production. This is the first study to use provincial, condition-specific emission factors based on most recently available studies on Chinese manure management and environmental conditions. The estimated NH 3 emission temporal trends and spatial patterns are interpreted in relation to government policies affecting livestock production. Scenario analysis is used to project emissions and estimate mitigation potential of NH 3 emissions, to year 2030. We produce a 1km×1km gridded NH 3 emission inventory for 2008 based on county-level activity data, which can help identify locations of highest NH 3 emissions. The total NH 3 emissions from manure generated by livestock production in 2008 were 7.3TgNH 3 ·yr -1 (interquartile range from 6.1 to 8.6TgNH 3 ·yr -1 ), and the major sources were poultry (29.9%), pigs (28.4%), other cattle (27.9%), and dairy cattle (7.0%), while sheep and goats (3.6%), donkeys (1.3%), horses (1.2%), and mules (0.7%) had smaller contributions. From 1978 to 2008, annual NH 3 emissions fluctuated with two peaks (1996 and 2006), and total emissions increased from 2.2 to 7.3Tg·yr -1 increasing on average 4.4%·yr -1 . Under a business-as-usual (BAU) scenario, NH 3 emissions in 2030 are expected to be 13.9TgNH 3 ·yr -1 (11.5-16.3TgNH 3 ·yr -1 ). Under mitigation scenarios, the projected emissions could be reduced by 18.9-37.3% compared to 2030 BAU emissions. This study improves our understanding of NH 3 emissions from livestock production, which is needed to guide stakeholders and policymakers to make well informed mitigation decisions for NH 3 emissions from livestock production at the country and regional levels. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. H2 dilution effect in the Cat-CVD processes of the SiH4/NH3 system

    International Nuclear Information System (INIS)

    Ansari, S.G.; Umemoto, Hironobu; Morimoto, Takashi; Yoneyama, Koji; Izumi, Akira; Masuda, Atsushi; Matsumura, Hideki

    2006-01-01

    Gas-phase diagnostics in the catalytic chemical vapor deposition processes of the SiH 4 /NH 3 /H 2 system were carried out to examine the effect of H 2 dilution. The decomposition efficiency of NH 3 showed a sharp decrease with the introduction of a small amount of SiH 4 , but this decrease was recovered by the addition of H 2 when the NH 3 pressure was low. On the other hand, at higher NH 3 pressures, the decomposition efficiency showed a minor dependence on the H 2 partial pressure. The addition of SiH 4 to the NH 3 system decreases the H-atom density by one order of magnitude, but this decrease is also recovered by H 2 addition. H atoms produced from H 2 must re-activate the catalyzer surfaces poisoned by SiH 4 when the NH 3 pressure is low

  8. Air exchange rates and migration of VOCs in basements and residences.

    Science.gov (United States)

    Du, L; Batterman, S; Godwin, C; Rowe, Z; Chin, J-Y

    2015-12-01

    Basements can influence indoor air quality by affecting air exchange rates (AERs) and by the presence of emission sources of volatile organic compounds (VOCs) and other pollutants. We characterized VOC levels, AERs, and interzonal flows between basements and occupied spaces in 74 residences in Detroit, Michigan. Flows were measured using a steady-state multitracer system, and 7-day VOC measurements were collected using passive samplers in both living areas and basements. A walk-through survey/inspection was conducted in each residence. AERs in residences and basements averaged 0.51 and 1.52/h, respectively, and had strong and opposite seasonal trends, for example, AERs were highest in residences during the summer, and highest in basements during the winter. Airflows from basements to occupied spaces also varied seasonally. VOC concentration distributions were right-skewed, for example, 90th percentile benzene, toluene, naphthalene, and limonene concentrations were 4.0, 19.1, 20.3, and 51.0 μg/m(3), respectively; maximum concentrations were 54, 888, 1117, and 134 μg/m(3). Identified VOC sources in basements included solvents, household cleaners, air fresheners, smoking, and gasoline-powered equipment. The number and type of potential VOC sources found in basements are significant and problematic, and may warrant advisories regarding the storage and use of potentially strong VOCs sources in basements. Few IAQ studies have examined basements. A sizable volume of air can flow between the basement and living area, and AERs in these two zones can differ considerably. In many residences, the basement contains significant emission sources and contributes a large fraction of VOC concentrations found in the living area. Exposures can be lowered by removing VOC sources from the basement; other exposure management options, such as local ventilation or isolation, are unlikely to be practical. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Nanoscale structural characterization of Mg(NH3)6Cl2 during NH3 desorption

    DEFF Research Database (Denmark)

    Jacobsen, Hjalte Sylvest; Hansen, Heine Anton; Andreasen, Jens Wenzel

    2007-01-01

    Complex metal hydrides progressively display improved hydrogen storage capacity, but they are still far from fulfilling the requirements of the transport sector. Recently, indirect storage of hydrogen as ammonia in Mg(NH3)(6)Cl-2 has shown impressive capacity and reversibility. Here, we present...

  10. Jet-Cooled Infrared Laser Spectroscopy in the Umbrella νb{2} Vibration Region of NH_3: Improving the Potential Energy Surface Model of the NH_3-Ar Van Der Waals Complex

    Science.gov (United States)

    Asselin, Pierre; Jabri, Atef; Potapov, Alexey; Loreau, Jérome; van der Avoird, Ad

    2017-06-01

    Taking advantage of our sensitive laser spectrometer coupled to a pulsed slit jet, we recorded near the νb{2} vibration a series of rovibrational transitions of the NH_3-Ar van der Waals (vdW) complex. These transitions involve in the ground vibrational state several internal rotor states corresponding to the ortho{NH_3} and para{NH_3} spin modifications of the complex. They are labeled by Σ_{a}(j,k), Σ_{s}(j,k), Π_{a}(j,k) and Π_{s}(j,k) where Σ(K=0) and Π(K=1) indicate the projection K of the total rotational angular momentum J on the vdW axis, the superscripts s and a designate a symmetric or antisymmetric NH_3 inversion wave function, and j, k quantum numbers indicate the correlation between the internal-rotor state of the complex and the j, k rotational state of the free NH_3 monomer. Five bands have been identified, only one of which was partly observed before. They include transitions starting from the Σ_{a}(j=0 or j=1) state without any internal angular momentum, consequently they can be assigned from the band contour of a linear-molecule-like K=0, ΔJ=1 transition. The energies and splittings of the rovibrational levels of the νb{2}=1←0 spectrum derived from the analysis of the Π_{s}, Σ_{s}(j=1)← Σ_{a}(j=0), k=0 bands and mostly of the Σ_{s}, Π_{s} and Σ_{a}(j=1)←Σ_{a}(j=1), k=1 bands bring relevant information about the νb{2} dependence of the NH_3-Ar interaction, the rovibrational dynamics of the NH_3-Ar complex and provide a sensitive test of a recently developed 4D potential energy surface that includes explicitly its dependence on the umbrella motion. P. Asselin, Y. Berger, T. R. Huet, R. Motiyenko, L. Margulès, R. J. Hendricks, M. R. Tarbutt, S. Tokunaga, B. Darquié, PCCP 19, 4576 (2017), G. T. Fraser, A.S. Pine and W. A. Kreiner, J. Chem. Phys. 94, 7061 (1991). J. Loreau, J. Liévin, Y. Scribano and A. van der Avoird, J. Chem. Phys. 141, 224303 (2014).

  11. Gas-particle interactions above a Dutch heathland: I. Surface exchange fluxes of NH3, SO2, HNO3 and HCl

    Directory of Open Access Journals (Sweden)

    E. Nemitz

    2004-01-01

    Full Text Available A field measurement campaign was carried out over a Dutch heathland to investigate the effect of gas-to-particle conversion and ammonium aerosol evaporation on surface/atmosphere fluxes of ammonia and related species. Continuous micrometeorological measurements of the surface exchange of NH3, SO2, HNO3 and HCl were made and are analyzed here with regard to average fluxes, deposition velocities (Vd, canopy resistances (Rc and canopy compensation point for NH3. Gradients of SO2, HNO3 and HCl were measured with a novel wet-denuder system with online anion chromatography. Measurements of HNO3 and HCl indicate an Rc of 100 to 200 s m-1 during warm daytime periods, probably at least partly due to non-zero acid partial pressures above NH4NO3 and NH4Cl on the leaf surfaces. Although it is likely that this observation is exacerbated by the effect of the evaporation of airborne NH4+ on the gradient measurements, the findings nevertheless add to the growing evidence that HNO3 and HCl are not always deposited at the maximum rate. Ammonia (NH3 fluxes show mainly deposition, with some periods of significant daytime emission. The net exchange could be reproduced both with an Rc model (deposition fluxes only using resistance parameterizations from former measurements, as well as with the canopy compensation point model, using parameterizations derived from the measurements. The apoplastic ratio of ammonium and hydrogen concentration (Γs=[NH4+]/[H+] of 1200 estimated from the measurements is large for semi-natural vegetation, but smaller than indicated by previous measurements at this site.

  12. Gas-particle interactions above a Dutch heathland: I. Surface exchange fluxes of NH3, SO2, HNO3 and HCl

    Science.gov (United States)

    Nemitz, E.; Sutton, M. A.; Wyers, G. P.; Jongejan, P. A. C.

    2004-07-01

    A field measurement campaign was carried out over a Dutch heathland to investigate the effect of gas-to-particle conversion and ammonium aerosol evaporation on surface/atmosphere fluxes of ammonia and related species. Continuous micrometeorological measurements of the surface exchange of NH3, SO2, HNO3 and HCl were made and are analyzed here with regard to average fluxes, deposition velocities (Vd), canopy resistances (Rc) and canopy compensation point for NH3. Gradients of SO2, HNO3 and HCl were measured with a novel wet-denuder system with online anion chromatography. Measurements of HNO3 and HCl indicate an Rc of 100 to 200 s m-1 during warm daytime periods, probably at least partly due to non-zero acid partial pressures above NH4NO3 and NH4Cl on the leaf surfaces. Although it is likely that this observation is exacerbated by the effect of the evaporation of airborne NH4+ on the gradient measurements, the findings nevertheless add to the growing evidence that HNO3 and HCl are not always deposited at the maximum rate. Ammonia (NH3) fluxes show mainly deposition, with some periods of significant daytime emission. The net exchange could be reproduced both with an Rc model (deposition fluxes only) using resistance parameterizations from former measurements, as well as with the canopy compensation point model, using parameterizations derived from the measurements. The apoplastic ratio of ammonium and hydrogen concentration (Γs=[NH4+]/[H+]) of 1200 estimated from the measurements is large for semi-natural vegetation, but smaller than indicated by previous measurements at this site.

  13. Effects of acute NH3 air pollution on N-sensitive and N-tolerant lichen species.

    Science.gov (United States)

    Paoli, Luca; Maslaňáková, Ivana; Grassi, Alice; Bačkor, Martin; Loppi, Stefano

    2015-12-01

    Lichens are sensitive to the presence of ammonia (NH3) in the environment. However, in order to use them as reliable indicators in biomonitoring studies, it is necessary to establish unequivocally the occurrence of certain symptoms following the exposure to NH3 in the environment. In this paper, we simulated an episode of acute air pollution due to the release of NH3. The biological effects of acute air pollution by atmospheric NH3 have been investigated using N-sensitive (Flavoparmelia caperata) and N-tolerant (Xanthoria parietina) species. Lichen samples were exposed to ecologically relevant NH3 concentrations for 8 weeks, simulating three areas of impact: a control area (2 μg/m(3)), an area of intermediate impact (2-35 μg/m(3)) and an area of high impact (10-315 μg/m(3)), with a peak of pollution reached between the fourth and fifth week. Ammonia affected both the photobiont and the mycobiont in F. caperata, while in X. parietina only the photosynthetic performance of the photobiont was altered after exposure to the highest concentration. In the photobiont of F. caperata we recorded chlorophyll degradation as indicated by OD435/415 ratio, decrease of the photosynthetic performance (as reflected by the maximum quantum yield of primary photochemistry FV/FM and the performance index PIABS); in the mycobiont, ergosterol reduction, membrane lipid peroxidation (as reflected by the increase of thiobarbituric acid reactive substances), alteration (decrease) of the secondary metabolite usnic acid. No effects were detected on caperatic acid and dehydrogenase activity. In X. parietina, the only signal determined by NH3 was the alteration of FV/FM and the performance index PIABS. The results suggest that physiological parameters in N-sensitive lichens well reflect the effects of NH3 exposure and can be applied as early indicators in monitoring studies. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. The development of a material for uranium sorption in NH_3/N environment

    International Nuclear Information System (INIS)

    Chen Xiaotong; He Linfeng; Liu Bing; Tang Yaping

    2014-01-01

    An efficient hybrid silica (TD-silica) bifunctionalized with trimethyl ammonium (TMAP) and phosphonate (DPTS) for Uranium (VI) extraction in NH_3/N media has been developed in this study. The hybrid silica was prepared by a post grafting of N-trimethoxysilylpropyl-N,N,N-trimethylammonium at large-pore silica. The resulting TD-modified silica were observed to possess a good stability and high efficiency for uranium (VI) sorption from solution in coexist with NH_3/N. The adsorbed uranium (VI) can be easily desorbed by using 0.05 mol/L HNO_3 and reused for at least 4 times. It is suggested that TD-silica could be a promising solid phase sorbent for highly-efficient removal of U(VI) from solution in coexist with NH_3/N. (author)

  15. Photogeneration of metastable side-on N2 linkage isomers in [Ru(NH3)5N2]Cl2, [Ru(NH3)5N2]Br2 and [Os(NH3)5N2]Cl2.

    Science.gov (United States)

    Schaniel, Dominik; Woike, Theo; Delley, Bernard; Boskovic, Colette; Güdel, Hans-Ueli

    2008-09-28

    Photogeneration of side-on N2 linkage isomers in [Ru(NH3)5N2]2+ and [Os(NH3)5N2]2+ is achieved by irradiation with lambda = 325 nm of powder samples at T = 80 K and detected by the downshift of the nu(N-N) vibration and by the heat release at elevated temperature due to the back switching of the side-on configuration to the ground state. The concentration of the transferred molecules is evaluated by the decrease of the area of the nu(N-N) or 2nu(N-N) vibrational bands. All characteristic changes between the linear Ru-N-N and side-on configuration are predicted by DFT calculations: the structure of the anion, shifts of the vibrations, electronic excitation energy, energetic position and sequence of the electronic orbitals, the potentials of the ground and relaxed metastable state with the activation energy, saddle points and energetic position of the minimum.

  16. Detrusor Arreflexia as an End Stage of Neurogenic Bladder in HAM/TSP?

    Directory of Open Access Journals (Sweden)

    Matheus Tannus

    2011-01-01

    Full Text Available The HTLV-1 virus is a known agent involved in the development of HAM/TSP. Past studies have typically observed patients with autonomic dysfunction consisting of detrusor overactivity and detrusor-sphincter dyssynergia, with the occasional observation of underactive detrusor or detrusor arreflexia. However, studies have not yet evaluated the progression of neurogenic bladder over time. In this paper, we describe a HAM/TSP patient with the initial development of overactive detrusor, and subsequent development of detrusor arreflexia. Given a paucity of studies characterizing the effects of HTLV-1 on the autonomic nervous system, particularly aspects controlling continence, this patient's clinical course may represent one type of end point for patients with HAM/TSP and neurogenic bladder. Further cohort or case-series studies, with particular emphasis on the progression of neurogenic bladder, are needed to evaluate the significance of this described case in relation to typical disease progression patterns.

  17. Comparative 4-E analysis of a bottoming pure NH3 and NH3-H2O mixture based power cycle for condenser waste heat recovery

    Science.gov (United States)

    Khankari, Goutam; Karmakar, Sujit

    2017-06-01

    This paper proposes a comparative performance analysis based on 4-E (Energy, Exergy, Environment, and Economic) of a bottoming pure Ammonia (NH3) based Organic Rankine Cycle (ORC) and Ammonia-water (NH3-H2O) based Kalina Cycle System 11(KCS 11) for additional power generation through condenser waste heat recovery integrated with a conventional 500MWe Subcritical coal-fired thermal power plant. A typical high-ash Indian coal is used for the analysis. The flow-sheet computer programme `Cycle Tempo' is used to simulate both the cycles for thermodynamic performance analysis at different plant operating conditions. Thermodynamic analysis is done by varying different NH3 mass fraction in KCS11 and at different turbine inlet pressure in both ORC and KCS11. Results show that the optimum operating pressure of ORC and KCS11 with NH3 mass fraction of 0.90 are about 15 bar and 11.70 bar, respectively and more than 14 bar of operating pressure, the plant performance of ORC integrated power plant is higher than the KCS11 integrated power plant and the result is observed reverse below this pressure. The energy and exergy efficiencies of ORC cycle are higher than the KCS11 by about 0.903 % point and 16.605 % points, respectively under similar saturation vapour temperature at turbine inlet for both the cycles. Similarly, plant energy and exergy efficiencies of ORC based combined cycle power plant are increased by 0.460 % point and 0.420 % point, respectively over KCS11 based combined cycle power plant. Moreover, the reduction of CO2 emission in ORC based combined cycle is about 3.23 t/hr which is about 1.5 times higher than the KCS11 based combined cycle power plant. Exergy destruction of the evaporator in ORC decreases with increase in operating pressure due to decrease in temperature difference of heat exchanging fluids. Exergy destruction rate in the evaporator of ORC is higher than KCS11 when the operating pressure of ORC reduces below 14 bar. This happens due to variable

  18. Establishing the tolerability and performance of tamarind seed polysaccharide (TSP in treating dry eye syndrome: results of a clinical study

    Directory of Open Access Journals (Sweden)

    Valente Cristiana

    2007-03-01

    Full Text Available Abstract Background One of the problems arising from available preparations for dry eye syndrome is the limited residence time of products on the ocular surface. In this paper, we look at an innovative new treatment for dry eye, tamarind seed polysaccharide (TSP. TSP possesses mucomimetic, mucoadhesive and pseudoplastic properties. The 'mucin-like' molecular structure of TSP is similar to corneal and conjunctival mucin 1 (MUC1, a transmembrane glycoprotein thought to play an essential role in protecting and wetting the corneal surface and may explain its increased retention on the eye surface. Methods The activity of TSP and hyaluronic acid (HA in the treatment of dry eye syndrome was compared in an open-label, randomised, single-centre clinical study. Thirty patients were randomised to receive three or more applications per day of either TSP 0.5%, TSP 1% or HA 0.2% (Hyalistil™ over a period of 90 days. The primary objective of tolerability was assessed by visual analogue scale (VAS, scoring of specific symptoms and the incidence of adverse events. Secondary objectives included improvement in stability of the precorneal tear film, subjective symptoms and corneal and conjunctival staining. Results TSP 0.5% and 1% were comparable to HA 0.2% with regard to both primary and secondary objective parameters. TSP 1% showed benefits over HA 0.2% for the subjective symptoms; trouble blinking, ocular burning and foreign body sensation. Conclusion This study suggests that TSP 0.5% and 1% offer at least equivalent relief to HA 0.2% for dry eye syndrome. All treatments demonstrated optimal tolerability and are suitable for frequent use in the therapy of dry eye. TSP 1% produced promising results in terms of improvements in certain patient symptoms and suggests benefits of the TSP formulation. This study paves the way for a larger study to further establish the performance and safety of TSP compared with HA and highlights the need to expand this therapeutic

  19. Wind tunnel evaluation of Hi-Vol TSP effectiveness data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Wind tunnel evaluation of EPA's Hi-Vol TSP sampler for sampling effectiveness with regards to aerodynamic particle diameter (5 to 35 microns), wind speed (2, 8, 24...

  20. Preparation of planar CH3NH3PbI3 thin films with controlled size using 1-ethyl-2-pyrrolidone as solvent

    International Nuclear Information System (INIS)

    Hao, Qiuyan; Chu, Yixia; Zheng, Xuerong; Liu, Zhenya; Liang, Liming; Qi, Jiakun; Zhang, Xin; Liu, Gang; Liu, Hui; Chen, Hongjian; Liu, Caichi

    2016-01-01

    Recently, planar perovskite solar cells based on CH 3 NH 3 PbI 3 have attracted many researcher's interest due to their unique advantages such as simple cell architecture, easy fabrication and potential multijunction construction comparing to the initial mesoporous structure. However, the preparation of planar perovskite films with high quality is still in challenge. In this paper, we developed a vapor-assisted solution process using a novel and green solvent of 1-Ethyl-2-pyrrolidone (NEP) instead of the traditional N, N-dimethylformamide (DMF) to construct a high-quality perovskite CH 3 NH 3 PbI 3 thin film with pure phase, high compactness, small surface roughness and controlled size. The phase evolution and growth mechanism of the perovskite films are also discussed. Utilizing the NEP of low volatility and moderate boiling point as solvent, we dried the PbI 2 -NEP precursor films at different temperature under vacuum and then obtained PbI 2 thin films with different crystalline degree from amorphous to highly crystalline. The perovskite films with crystal size ranged from hundreds of nanometers to several micrometers can be prepared by reacting the PbI 2 films of different crystalline degree with CH 3 NH 3 I vapor. Moreover, planar-structured solar cells combining the perovskite film with TiO 2 and spiro-OMeTAD as the electron and holes transporting layer achieves a power conversion efficiency of 10.2%. - Highlights: • A novel and green solvent of 1-Ethyl-2-pyrrolidone (NEP) was used to construct high-quality perovskite CH 3 NH 3 PbI 3 thin film. • The CH 3 NH 3 PbI 3 grain with different sizes ranged from hundreds of nanometers to several micrometers can be obtained. • Planar-structured perovskite CH 3 NH 3 PbI 3 solar cells using NEP as solvent achieves a power conversion efficiency of 10.2%.

  1. [Emission Characteristics of VOCs from Typical Restaurants in Beijing].

    Science.gov (United States)

    Cui, Tong; Cheng, Jing-chen; He, Wan-qing; Ren, Pei-fang; Nie, Lei; Xu, Dong-yao; Pan, Tao

    2015-05-01

    Using the EPA method, emission of volatile organic compounds (VOCs) , sampled from barbecue, Chinese and Western fast-food, Sichuan cuisine and Zhejiang cuisine restaurants in Beijing was investigated. VOCs concentrations and components from different cuisines were studied. The results indicated that based on the calibrated baseline ventilation volume, the VOCs emission level from barbecue was the highest, reaching 12.22 mg · m(-3), while those from fast-food of either Chinese or Western, Sichuan cuisine and Zhejiang cuisine were about 4 mg · m(-3). The components of VOCs from barbecue were different from those in the other cuisines, which were mainly propylene, 1-butene, n-butane, etc. The non-barbecue cuisines consisted of high concentration of alcohols, and Western fast-food contained relatively high proportion of aldehydes and ketones organic compounds. According to emission concentration of baseline ventilation volume, barbecue released more pollutants than the non-barbecue cuisines at the same scale. So, barbecue should be supervised and controlled with the top priority.

  2. Theoretical study on the mechanism of CH3NH2 and O3 ...

    Indian Academy of Sciences (India)

    CH3NH + OH + O2 adducts with one transition state is the most favoured path. Keywords. Ozone; calculation; reaction mechanism; potential energy profile; transition state. 1. Introduction ..... University of. Applied Science, Bielefeld, Germany.

  3. Surface study of platinum decorated graphene towards adsorption of NH{sub 3} and CH{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Rad, Ali Shokuhi, E-mail: a.shokuhi@gmail.com [Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Pazoki, Hossein; Mohseni, Soheil [Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Zareyee, Daryoush [Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Peyravi, Majid [Faculty of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of)

    2016-10-01

    To distinguish the potential of graphene sensors, there is a need to recognize the interaction between graphene sheet and adsorbing molecules. We used density functional theory (DFT) calculations to study the properties of pristine as well as Pt-decorated graphene sheet upon adsorption of NH{sub 3} and CH{sub 4} on its surface to exploit its potential to be as gas sensors for them. We found much higher adsorption, higher charge transfer, lower intermolecular distance, and higher orbital hybridizing upon adsorption of NH{sub 3} and CH{sub 4} gas molecules on Pt-decorated graphene compared to pristine graphene. Also our calculations reveal that the adsorption energies on Pt-decorated graphene sheet are in order of NH{sub 3} >CH{sub 4} which could be corresponded to the order of their sensitivity on this modified surface. We used orbital analysis including density of states as well as frontier molecular orbital study for all analyte-surface systems to more understanding the kind of interaction (physisorption or chemisorption). Consequently, the Pt-decorated graphene can transform the existence of NH{sub 3} and CH{sub 4} molecules into electrical signal and it may be potentially used as an ideal sensor for detection of NH{sub 3} and CH{sub 4} in ambient situation. - Highlights: • Pt-decorated graphene was investigated as an adsorbent for NH{sub 3} and CH{sub 4}. • Much higher adsorption of NH{sub 3} and CH{sub 4} on Pt-decorated graphene than pristine graphene. • Higher adsorption of NH{sub 3} compared to CH{sub 4} on Pt-decorated graphene. • Pt influences the electronic structure of graphene.

  4. Evidence of amino acid precursors: C-N bond coupling in simulated interstellar CO2/NH3 ices

    Science.gov (United States)

    Esmaili, Sasan

    2015-08-01

    Low energy secondary electrons are abundantly produced in astrophysical or planetary ices by the numerous ionizing radiation fields typically encountered in space environments and may thus play a role in the radiation processing of such ices [1]. One approach to determine their chemical effect is to irradiate nanometer thick molecular solids of simple molecular constituents, with energy selected electron beams and to monitor changes in film chemistry with the surface analytical techniques [2].Of particular interest is the formation of HCN, which is a signature of dense gases in interstellar clouds, and is ubiquitous in the ISM. Moreover, the chemistry of HCN radiolysis products such as CN- may be essential to understand of the formation of amino acids [3] and purine DNA bases. Here we present new results on the irradiation of multilayer films of CO2 and NH3 with 70 eV electrons, leading to CN bond formations. The electron stimulated desorption (ESD) yields of cations and anions are recorded as a function of electron fluence. The prompt desorption of cationic reaction/scattering products [4], is observed at low fluence (~4x1013 electrons/cm2). Detected ions include C2+, C2O2+, C2O+, CO3+, C2O3+ or CO4+ from pure CO2, and N+, NH+, NH2+, NH3+, NH4+, N2+, N2H+ from pure NH3, and NO+, NOH+ from CO2/NH3 mixtures. Most saliently, increasing signals of negative ion products desorbing during prolonged irradiation of CO2/NH3 films included C2-, C2H-, C2H2-, as well as CN-, HCN- and H2CN-. The identification of particular product ions was accomplished by using 13CO2 and 15NH3 isotopes. The chemistry induced by electrons in pure films of CO2 and NH3 and mixtures with composition ratios (3:1), (1:1), and (1:3), was also studied by X-ray photoelectron spectroscopy (XPS). Irradiation of CO2/NH3 mixed films at 22 K produces species containing the following bonds/functional groups identified by XPS: C=O, O-H, C-C, C-O, C=N and N=O. (This work has been funded by NSERC).

  5. Process for uranium separation and preparation of UO4.2NH3.2HF

    International Nuclear Information System (INIS)

    Dokuzoguz, H.Z.

    1976-01-01

    A process for treating the aqueous effluents that are produced in converting gaseous UF 6 (uranium hexafluoride) into solid UO 2 (uranium dioxide) by way of an intermediate (NH 4 ) 4 UO 2 (CO 3 ) 3 (''AUC'' Compound) is disclosed. These effluents, which contain large amounts of NH 4 + , CO 3 2- , F - , and a small amount of U are mixed with H 2 SO 4 (sulfuric acid) in order to expel CO 2 (carbon dioxide) and thereby reduce the carbonate concentration. The uranium is precipitated through treatment with H 2 O 2 (hydrogen peroxide) and the fluoride is easily recovered in the form of CaF 2 (calcium fluoride) by contacting the process liquid with CaO (calcium oxide). The presence of SO 4 2- (sulfate) in the process liquid during CaO contacting seems to prevent the development of a difficult-to-filter colloid. The process also provides for NH 3 recovery and recycling. Liquids discharged from the process, moreover, are essentially free of environmental pollutants. The waste treatment products, i.e., CO 2 , NH 3 , and U are economically recovered and recycled back into the UF 6 → UO 2 conversion process. The process, moreover, recovers the uranium as a precipitate in the second stage. This precipitate is a new inorganic chemical compound UO 4 .2NH 3 .2HF [uranyl peroxide-2-ammonia-2-(hydrogen fluoride)

  6. Data-Acquisition Software for PSP/TSP Wind-Tunnel Cameras

    Science.gov (United States)

    Amer, Tahani R.; Goad, William K.

    2005-01-01

    Wing-Viewer is a computer program for acquisition and reduction of image data acquired by any of five different scientificgrade commercial electronic cameras used at Langley Research center to observe wind-tunnel models coated with pressure or temperature-sensitive paints (PSP/TSP). Wing-Viewer provides full automation of camera operation and acquisition of image data, and has limited data-preprocessing capability for quick viewing of the results of PSP/TSP test images. Wing- Viewer satisfies a requirement for a standard interface between all the cameras and a single personal computer: Written by use of Microsoft Visual C++ and the Microsoft Foundation Class Library as a framework, Wing-Viewer has the ability to communicate with the C/C++ software libraries that run on the controller circuit cards of all five cameras.

  7. Carrier injection and recombination processes in perovskite CH3NH3PbI3 solar cells studied by electroluminescence spectroscopy

    Science.gov (United States)

    Handa, Taketo; Okano, Makoto; Tex, David M.; Shimazaki, Ai; Aharen, Tomoko; Wakamiya, Atsushi; Kanemitsu, Yoshihiko

    2016-02-01

    Organic-inorganic hybrid perovskite materials, CH3NH3PbX3 (X = I and Br), are considered as promising candidates for emerging thin-film photovoltaics. For practical implementation, the degradation mechanism and the carrier dynamics during operation have to be clarified. We investigated the degradation mechanism and the carrier injection and recombination processes in perovskite CH3NH3PbI3 solar cells using photoluminescence (PL) and electroluminescence (EL) imaging spectroscopies. By applying forward bias-voltage, an inhomogeneous distribution of the EL intensity was clearly observed from the CH3NH3PbI3 solar cells. By comparing the PL- and EL-images, we revealed that the spatial inhomogeneity of the EL intensity is a result of the inhomogeneous luminescence efficiency in the perovskite layer. An application of bias-voltage for several tens of minutes in air caused a decrease in the EL intensity and the conversion efficiency of the perovskite solar cells. The degradation mechanism of perovskite solar cells under bias-voltage in air is discussed.

  8. Accounting for Field-Scale Dry Deposition in Backward Lagrangian Stochastic Dispersion Modelling of NH3 Emissions

    Directory of Open Access Journals (Sweden)

    Christoph Häni

    2018-04-01

    Full Text Available A controlled ammonia (NH3 release experiment was performed at a grassland site. The aim was to quantify the effect of dry deposition between the source and the receptors (NH3 measurement locations on emission rate estimates by means of inverse dispersion modelling. NH3 was released for three hours at a constant rate of Q = 6.29 mg s−1 from a grid of 36 orifices spread over an area of 250 m2. The increase in line-integrated NH3 concentration was measured with open-path optical miniDOAS devices at different locations downwind of the artificial source. Using a backward Lagrangian stochastic (bLS dispersion model (bLSmodelR, the fraction of the modelled release rate to the emitted NH3 ( Q bLS / Q was calculated from the measurements of the individual instruments. Q bLS / Q was found to be systematically lower than 1, on average between 0.69 and 0.91, depending on the location of the receptor. We hypothesized that NH3 dry deposition to grass and soil surfaces was the main factor responsible for the observed depletion of NH3 between source and receptor. A dry deposition algorithm based on a deposition velocity approach was included in the bLS modelling. Model deposition velocities were evaluated from a ‘big-leaf’ canopy resistance analogy. Canopy resistances (generally termed R c that provided Q bLS / Q = 1 ranged from 75 to 290 s m−1, showing that surface removal of NH3 by dry deposition can plausibly explain the original underestimation of Q bLS / Q . The inclusion of a dry deposition process in dispersion modelling is crucial for emission estimates, which are based on concentration measurements of depositing tracers downwind of homogeneous area sources or heterogeneously-distributed hot spots, such as, e.g., urine patches on pastures in the case of NH3.

  9. Volatile Organic Compound (VOC) Emissions from Dairy Cows and Their Waste

    Science.gov (United States)

    Shaw, S.; Holzinger, R.; Mitloehner, F.; Goldstein, A.

    2005-12-01

    Biogenic VOCs are typically defined as those directly emitted from plants, but approximately 6% of global net primary production is consumed by cattle that carry out enteric fermentation and then emit VOCs that could also be considered biogenic. Current regulatory estimates suggest that dairy cattle in central California emit VOCs at rates comparable to those from passenger vehicles in the region, and thus contribute significantly to the extreme non-attainment of ozone standards there. We report PTR-MS measurements of ammonia and VOCs, and cavity-enhanced-absorption gas analyzer (Los Gatos Research, Inc.) measurements of CH4, emitted from dairy cattle in various stages of pregnancy/lactation and their waste. Experiments were conducted in chambers at UC Davis that simulate freestall cow housing conditions. CH4 fluxes ranged from 125-374 lb/cow/year. The compounds with the highest fluxes from '3 cows+waste' treatments were: ammonia (1-18), methanol (0-2.3), acetone+propanal (0.2-0.7), dimethylsulfide (0-0.4), and mass 109 (likely ID = p-cresol; 0-0.3) in lb/cow/year. Mass 60 (likely ID = trimethylamine) and acetic acid were also abundant. There were 10s of additional compounds with detectable, but small, emissions. A few compounds that were likely emitted (i.e. ethanol, formaldehyde, and dimethylamine) were not quantified by the PTR-MS. The total flux for all measured organic gases (TOG = CH4 + PTR-MS VOCs(including acetone+propanal)) averaged 246±45 lb/cow/year for '3 cows+waste' treatments, and was dominated by methane (>98%). TOG flux for 'waste only' treatments averaged 1.1±0.1 lb/cow/year, and was instead dominated by VOC (>84%). The PTR-MS VOCs as a percent of TOG (0.6±0.2%) emitted from '3 cows+waste' treatments in chamber conditions was a factor of 10 smaller than that currently estimated by the California Air Resources Board. In addition, the ozone forming potentials of the most abundant VOCs are only about 10% those of typical combustion or plant

  10. Trends of NO-, NO 2-, and NH 3-emissions from gasoline-fueled Euro-3- to Euro-4-passenger cars

    Science.gov (United States)

    Heeb, Norbert V.; Saxer, Christian J.; Forss, Anna-Maria; Brühlmann, Stefan

    Vehicular emissions of reactive nitrogen compounds (RNCs) such as nitric oxide (NO), nitrogen dioxide (NO 2), and ammonia (NH 3) have a substantial impact on urban air quality. NO and NO 2 support the photochemical formation of ozone, and NH 3 is involved in the atmospheric formation of secondary aerosols. Vehicular NO is mainly formed during combustion, whereas NO 2 and NH 3 are both secondary pollutants of the catalytic converter systems. Herein we report on tail-pipe RNC emissions of gasoline-fueled Euro-3- and Euro-4-passenger cars at transient driving from 0 to 150 km h -1. Two sets of 10 in-use vehicles with comparable engine size and mileage were studied with time-resolved chemical ionization-mass spectrometry (CI-MS). Each vehicle was tested in 7 different driving cycles including the legislative European (EDC) and the US FTP-75 driving cycles. Mean emission factors (EFs) for different traffic situations are reported and effects of cold start, velocity, acceleration, and deceleration are discussed. Furthermore, critical operating conditions supporting the de novo formation of NH 3 have been identified. In the EDC, mean NO- and NH 3-EFs of 57±26 and 16±12 mg km -1 were obtained for Euro-3-vehicles; those of the Euro-4-technology were lower by about 25% and 33% at the levels of 43±46 and 10±7 mg km -1, respectively. NO 2 emissions of the investigated three-way catalyst (TWC) vehicles accounted for exhaust. Velocity and acceleration had pronounced effects on the RNC emission characteristics. Mean velocity-dependent EFs for NO and NH 3 varied by about one order of magnitude from 10 to 74 and 15 to 161 mg km -1 for Euro-3-vehicles and from 12 to 44 and 7 to 144 mg km -1 for the Euro-4 fleet. We conclude that the investigated Euro-3- and Euro-4-vehicles are mainly operated under slightly reducing conditions, where the NH 3 emissions dominate over those of the NO. Under these conditions, both vehicle fleets on an average fulfilled the valid Euro-3 and Euro-4

  11. Corrosion and solubility in a TSP-buffered chemical environment following a loss of coolant accident: Part 1 – Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Howe, Kerry J., E-mail: howe@unm.edu [University of New Mexico, 210 University Blvd., Albuquerque, NM 87131 (United States); Mitchell, Lana, E-mail: lmitchell@alionscience.com [University of New Mexico, 210 University Blvd., Albuquerque, NM 87131 (United States); Kim, Seung-Jun, E-mail: skim@lanl.gov [University of New Mexico, 210 University Blvd., Albuquerque, NM 87131 (United States); Blandford, Edward D., E-mail: edb@unm.edu [University of New Mexico, 210 University Blvd., Albuquerque, NM 87131 (United States); Kee, Ernest J., E-mail: erniekee@gmail.com [South Texas Project Nuclear Operating Company, P.O. Box 270, Wadsworth, TX 77483 (United States)

    2015-10-15

    Highlights: • Trisodium phosphate (TSP) causes aluminum corrosion to cease after 24 h of exposure. • Chloride, iron, and copper have a minimal effect on the rate of aluminum corrosion when TSP is present. • Zinc can reduce the rate of aluminum corrosion when TSP is present. • Aluminum occasionally precipitates at concentrations lower than the calculated solubility for Al(OH){sub 3}. • Corrosion and solubility equations can be used to calculate the solids generated during a LOCA. - Abstract: Bench experiments were conducted to investigate the effect of the presence of trisodium phosphate (TSP) on the corrosion and release of aluminum from metallic aluminum surfaces under conditions representative of the containment pool following a postulated loss of coolant accident at a nuclear power generating facility. The experiments showed that TSP is capable of passivating the aluminum surface and preventing continued corrosion after about 24 h at the conditions tested. A correlation that describes the rate of corrosion including the passivation effect was developed from the bench experiments and validated with a separate set of experiments from a different test system. The saturation concentration of aluminum was shown to be well described by the solubility of amorphous aluminum hydroxide for the majority of cases, but instances have been observed when aluminum precipitates at concentrations lower than the calculated aluminum hydroxide solubility. Based on the experimental data and previous literature, an equation was developed to calculate the saturation concentration of aluminum as a function of pH and temperature under conditions representative of a loss of coolant accident (LOCA) in a TSP-buffered pressurized water reactor (PWR) containment. The corrosion equation and precipitation equation can be used in concert with each other to calculate the quantity of solids that would form as a function of time during a LOCA if the temperature and pH profiles were known.

  12. Corrosion and solubility in a TSP-buffered chemical environment following a loss of coolant accident: Part 1 – Aluminum

    International Nuclear Information System (INIS)

    Howe, Kerry J.; Mitchell, Lana; Kim, Seung-Jun; Blandford, Edward D.; Kee, Ernest J.

    2015-01-01

    Highlights: • Trisodium phosphate (TSP) causes aluminum corrosion to cease after 24 h of exposure. • Chloride, iron, and copper have a minimal effect on the rate of aluminum corrosion when TSP is present. • Zinc can reduce the rate of aluminum corrosion when TSP is present. • Aluminum occasionally precipitates at concentrations lower than the calculated solubility for Al(OH) 3 . • Corrosion and solubility equations can be used to calculate the solids generated during a LOCA. - Abstract: Bench experiments were conducted to investigate the effect of the presence of trisodium phosphate (TSP) on the corrosion and release of aluminum from metallic aluminum surfaces under conditions representative of the containment pool following a postulated loss of coolant accident at a nuclear power generating facility. The experiments showed that TSP is capable of passivating the aluminum surface and preventing continued corrosion after about 24 h at the conditions tested. A correlation that describes the rate of corrosion including the passivation effect was developed from the bench experiments and validated with a separate set of experiments from a different test system. The saturation concentration of aluminum was shown to be well described by the solubility of amorphous aluminum hydroxide for the majority of cases, but instances have been observed when aluminum precipitates at concentrations lower than the calculated aluminum hydroxide solubility. Based on the experimental data and previous literature, an equation was developed to calculate the saturation concentration of aluminum as a function of pH and temperature under conditions representative of a loss of coolant accident (LOCA) in a TSP-buffered pressurized water reactor (PWR) containment. The corrosion equation and precipitation equation can be used in concert with each other to calculate the quantity of solids that would form as a function of time during a LOCA if the temperature and pH profiles were known

  13. Socioeconomic Differences in Exposure to Tobacco Smoke Pollution (TSP in Bangladeshi Households with Children: Findings from the International Tobacco Control (ITC Bangladesh Survey

    Directory of Open Access Journals (Sweden)

    Geoffrey T. Fong

    2011-03-01

    Full Text Available This study assessed the pattern of exposure to tobacco smoke pollution (TSP; also known as, secondhand smoke in Bangladeshi households with children and examined the variations in household smoking restrictions and perception of risk for children’s exposure to TSP by socioeconomic status. We interviewed 1,947 respondents from Bangladeshi households with children from the first wave (2009 of the International Tobacco Control (ITC Bangladesh Survey. 43.5% of the respondents had complete smoking restrictions at home and 39.7% were very or extremely concerned about TSP risk to children’s health. Participants with lower level of education were significantly less likely to be concerned about the risk of TSP exposure to children’s health and less likely to adopt complete smoking restrictions at home. Logistic regression revealed that the predictors of concern for TSP exposure risk were educational attainment of 1 to 8 years (OR = 1.94 or 9 years or more (OR = 4.07 and being a smoker (OR = 0.24. The predictors of having complete household smoking restrictions were: urban residence (OR = 1.64, attaining education of 9 years or more (OR = 1.94, being a smoker (OR = 0.40 and being concerned about TSP exposure risk to children (OR = 3.25. The findings show that a high proportion of adults with children at home smoke tobacco at home and their perceptions of risk about TSP exposure to children’s health were low. These behaviours were more prevalent among rural smokers who were illiterate. There is a need for targeted intervention, customized for low educated public, on TSP risk to children’s health and tobacco control policy with specific focus on smoke-free home.

  14. VOC emissions control systems

    International Nuclear Information System (INIS)

    Spessard, J.E.

    1993-01-01

    The air pollution control equipment marketplace offers many competing technologies for controlling emissions of volatile organic compounds (VOC) in air. If any technology was economically and technically superior under all conditions, it would be the only one on the market. In fact, each technology used to control VOCs is superior under some set of conditions. The reasons for choosing one control technology over another are situation-specific. Some general guidelines to VOC control technologies and the situations where each may be appropriate are presented in this article. The control technologies and applications are summarized in a table

  15. In situ DRIFTS investigation of NH3-SCR reaction over CeO2/zirconium phosphate catalyst

    Science.gov (United States)

    Zhang, Qiulin; Fan, Jie; Ning, Ping; Song, Zhongxian; Liu, Xin; Wang, Lanying; Wang, Jing; Wang, Huimin; Long, Kaixian

    2018-03-01

    A series of ceria modified zirconium phosphate catalysts were synthesized for selective catalytic reduction of NO with ammonia (NH3-SCR). Over 98% NOx conversion and 98% N2 selectivity were obtained by the CeO2/ZrP catalyst with 20 wt.% CeO2 loading at 250-425 °C. The interaction between CeO2 and zirconium phosphate enhanced the redox abilities and surface acidities of the catalysts, resulting in the improvement of NH3-SCR activity. The in situ DRIFTS results indicated that the NH3-SCR reaction over the catalysts followed both Eley-Rideal and Langmuir-Hinshelwood mechanisms. The amide (sbnd NH2) groups and the NH4+ bonded to Brønsted acid sites were the important intermediates of Eley-Rideal mechanism.

  16. The Green Bank Ammonia Survey: First Results of NH3 Mapping of the Gould Belt

    Science.gov (United States)

    Friesen, Rachel K.; Pineda, Jaime E.; co-PIs; Rosolowsky, Erik; Alves, Felipe; Chacón-Tanarro, Ana; How-Huan Chen, Hope; Chun-Yuan Chen, Michael; Di Francesco, James; Keown, Jared; Kirk, Helen; Punanova, Anna; Seo, Youngmin; Shirley, Yancy; Ginsburg, Adam; Hall, Christine; Offner, Stella S. R.; Singh, Ayushi; Arce, Héctor G.; Caselli, Paola; Goodman, Alyssa A.; Martin, Peter G.; Matzner, Christopher; Myers, Philip C.; Redaelli, Elena; The GAS Collaboration

    2017-07-01

    We present an overview of the first data release (DR1) and first-look science from the Green Bank Ammonia Survey (GAS). GAS is a Large Program at the Green Bank Telescope to map all Gould Belt star-forming regions with {A}{{V}}≳ 7 mag visible from the northern hemisphere in emission from NH3 and other key molecular tracers. This first release includes the data for four regions in the Gould Belt clouds: B18 in Taurus, NGC 1333 in Perseus, L1688 in Ophiuchus, and Orion A North in Orion. We compare the NH3 emission to dust continuum emission from Herschel and find that the two tracers correspond closely. We find that NH3 is present in over 60% of the lines of sight with {A}{{V}}≳ 7 mag in three of the four DR1 regions, in agreement with expectations from previous observations. The sole exception is B18, where NH3 is detected toward ∼40% of the lines of sight with {A}{{V}}≳ 7 mag. Moreover, we find that the NH3 emission is generally extended beyond the typical 0.1 pc length scales of dense cores. We produce maps of the gas kinematics, temperature, and NH3 column densities through forward modeling of the hyperfine structure of the NH3 (1, 1) and (2, 2) lines. We show that the NH3 velocity dispersion, {σ }v, and gas kinetic temperature, T K, vary systematically between the regions included in this release, with an increase in both the mean value and the spread of {σ }v and T K with increasing star formation activity. The data presented in this paper are publicly available (https://dataverse.harvard.edu/dataverse/GAS_DR1).

  17. [Effects of superphosphate addition on NH3 and greenhouse gas emissions during vegetable waste composting].

    Science.gov (United States)

    Yang, Yan; Sun, Qin-ping; Li, Ni; Liu, Chun-sheng; Li, Ji-jin; Liu, Ben-sheng; Zou, Guo-yuan

    2015-01-01

    To study the effects of superphosphate (SP) on the NH, and greenhouse gas emissions, vegetable waste composting was performed for 27 days using 6 different treatments. In addition to the controls, five vegetable waste mixtures (0.77 m3 each) were treated with different amounts of the SP additive, namely, 5%, 10%, 15%, 20% and 25%. The ammonia volatilization loss and greenhouse gas emissions were measured during composting. Results indicated that the SP additive significantly decreased the ammonia volatilization and greenhouse gas emissions during vegetable waste composting. The additive reduced the total NH3 emission by 4.0% to 16.7%. The total greenhouse gas emissions (CO2-eq) of all treatments with SP additives were decreased by 10.2% to 20.8%, as compared with the controls. The NH3 emission during vegetable waste composting had the highest contribution to the greenhouse effect caused by the four different gases. The amount of NH3 (CO2-eq) from each treatment ranged from 59.90 kg . t-1 to 81.58 kg . t-1; NH3(CO2-eq) accounted for 69% to 77% of the total emissions from the four gases. Therefore, SP is a cost-effective phosphorus-based fertilizer that can be used as an additive during vegetable waste composting to reduce the NH3 and greenhouse gas emissions as well as to improve the value of compost as a fertilizer.

  18. Effects of GeI2 or ZnI2 addition to perovskite CH3NH3PbI3 photovoltaic devices

    Science.gov (United States)

    Tanaka, Hiroki; Ohishi, Yuya; Oku, Takeo

    2018-01-01

    CH3NH3PbI3 added with GeI2 or ZnI2 perovskite photovoltaic devices were fabricated characterized. The surface coverages of the perovskite layers were improved by the addition of GeI2 or ZnI2. Formation of PbI2 observed for the pristine CH3NH3PbI3 was suppressed by the GeI2 or ZnI2 addition, which resulted in the improvement of the conversion efficiencies of the perovskite photovoltaic devices.

  19. Utilisation of VOC in Diesel Engines. Ignition and combustion of VOC released in crude oil tankers

    International Nuclear Information System (INIS)

    Melhus, Oeyvin

    2002-01-01

    The emission of VOC (Volatile Organic Compound) is a significant source of hydrocarbon pollution. In Norway, the offshore oil industry represents a major source. This emission represents both an energy loss and an environmental problem. Gas tankers have used boil-off gas from the cargo tanks as fuel for some time. However, for the current VOC project a new fuel injection concept is designed for tankers to take advantage of the energy present in the VOC evaporated from crude oil. The VOC is mixed with inert gas in these tankers, and thus the utilisation of this gas represents new challenges. The VOC project uses the concept of ''Condensate Diesel Process'' with pilot ignition. An experimental study of ignition and combustion of VOC Fuels reported here was initiated by the time it was decided to start a pilot project converting propulsion engines in shuttle tankers to use VOC Fuel. It is an experimental study carried out at the Marine Technology Centre (MTS). The objective was to study ignition and combustion of the chosen process in comparison with an ordinary diesel process. The experimental results have been discussed and compared with theoretical considerations of injection, ignition and combustion. For experiments on combustion, a rapid compression machine ''DyFo'' was redesigned to use VOC Fuel. The DyFo test rig was initially designed to study ignition and early combustion of spark ignited homogeneous gas/air charges. To study the ignition and early combustion of VOC Fuel injected at high pressure and ignited by pilot diesel fuel, a redesign was necessary. An important feature of the DyFo, is the visualisation of the combustion. The advantage of the DyFo test rig over an engine, is its simplicity and controllability. In an engine the visualisation would suffer from combustion deposits disturbing the view through the quartz glasses, making the images more difficult to interpret. The simplicity is on the other side a drawback. Correct thermal conditions inside

  20. Chemical mass balance source apportionment of TSP in a lignite-burning area of Western Macedonia, Greece

    Science.gov (United States)

    Samara, Constantini

    Total suspended particle mass concentrations (TSP) were determined in the Kozani-Ptolemais-Florina basin (western Macedonia, Greece), an area with intensive lignite burning for power generation. The study was conducted over a 1-year period (November 2000-November 2001) at 10 receptor sites located at variable distances from the power plants. Ambient TSP samples were analyzed for 27 major, minor and trace elements. Particulate emissions were also collected from a variety of sources including fly ash, lignite dust, automobile traffic, domestic heating, and open-air burning of agricultural biomass and refuse, and analyzed for the same chemical components. Ambient and source chemical profiles were used for source identification and apportionment of TSP by employing a chemical mass balance (CMB) receptor model. Diesel burning in vehicular traffic and in the power plants for generator start up was found to be the major contributor to ambient TSP levels at all 10 sites. Other sources with significant contributions were domestic coal burning, vegetative burning (wood combustion and agricultural burns) and refuse open-air burning. Fly ash escaping the electrostatic precipitators of the power plants was a minor contributor to ambient TSP.

  1. IMPLEMENTASI ALGORITMA TSP DALAM PENYELESAIAN TRACKING PAKET PADA UNIT PROCESSING CENTER POS INDONESIA KOTA LHOKSEUMAWE ACEH

    Directory of Open Access Journals (Sweden)

    Richki Hardi

    2015-04-01

    Full Text Available Traveling salesperson problem-TSP problem is an optimization problem to find the optimal way for the traveling salesman who wants to visit several cities, and returned to the original departure city. TSP is a difficult problem when viewed from the point of computing. Several methods have been used to solve these problems but until now not been found mangkus algorithms to solve them. The easiest way to solve TSP is to try all possible routes and find the optimal route. However, at the time of the very practical now required to complete an algorithm that quickly so that the TSP solution obtained near optimal solutions.TSP is very precise algorithm used for solving complex optimization problems and solved difficult conventional methods. Route and distance data used to determine the optimal route in the system is obtained from the survey results at the post office Lhokseumawe. The results showed that the algorithm is the shortest route from the post office to post office Lhokseumawe, Meulaboh, Lhokseumawe is through the route - Bireun-Simpang Tiga-Takengon-Meulaboh with a total distance of 326 kilometers. The implementation of this system using the programming language PHP, MySQL, and Macromedia Flash.

  2. Use of Combined Observational- and Model-Derived Photochemical Indicators to Assess the O3-NOx-VOC System Sensitivity in Urban Areas

    Directory of Open Access Journals (Sweden)

    Edson R. Carrillo-Torres

    2017-01-01

    Full Text Available Tropospheric levels of O3 have historically exceeded the official annual Mexican standards within the Monterrey Metropolitan Area (MMA in NE Mexico. High-frequency and high-precision measurements of tropospheric O3, NOy, NO2, NO, CO, SO2, PM10 and PM2.5 were made at the Obispado monitoring site near the downtown MMA from September 2012 to August 2013. The seasonal cycles of O3 and NOy are driven by changes in meteorology and to a lesser extent by variations in primary emissions. The NOy levels were positively correlated with O3 precursors and inversely correlated with O3 and wind speed. Recorded data were used to assess the O3-Volatile Organic Compounds (VOC-NOx system’s sensitivity through an observational-based approach. The photochemical indicator O3/NOy was derived from measured data during the enhanced O3 production period (12:00–18:00 Central Daylight Time (CDT, GMT-0500. The O3/NOy ratios calculated for this time period showed that the O3 production within the MMA is VOC sensitive. A box model simulation of production rates of HNO3 (PHNO3 and total peroxides (Pperox carried out for O3 episodes in fall and spring confirmed the VOC sensitivity within the MMA environment. No significant differences were observed in O3/NOy from weekdays to weekends or for PHNO3/Pperox ratios, confirming the limiting role of VOCs in O3 production within the MMA. The ratified photochemical regime observed may allow the environmental authorities to revise and verify the current policies for air quality control within the MMA.

  3. CH3NH3PbCl3 Single Crystals: Inverse Temperature Crystallization and Visible-Blind UV-Photodetector

    KAUST Repository

    Maculan, Giacomo; Sheikh, Arif D.; Abdelhady, Ahmed L.; Saidaminov, Makhsud I.; Haque, Mohammed; Banavoth, Murali; Alarousu, Erkki; Mohammed, Omar F.; Wu, Tao; Bakr, Osman

    2015-01-01

    a new method of sizeable CH3NH3PbCl3 single crystal growth based on retrograde solubility behavior of hybrid perovskites. We show, for the first time, the energy band structure, charge-carrier recombination and transport properties of single crystal

  4. Single-crystal perovskite CH3NH3PbBr3 prepared by cast capping method for light-emitting diodes

    Science.gov (United States)

    Nguyen, Van-Cao; Katsuki, Hiroyuki; Sasaki, Fumio; Yanagi, Hisao

    2018-04-01

    In this study, electroluminescence from single crystals of CH3NH3PbBr3 perovskite is explored. The cast capping method was applied to fabricate simple devices with an ITO/CH3NH3PbBr3/ITO structure. The devices showed a low operation voltage of 2 V and a pure green luminescence with full width at half maximum of ∼20 nm. However, the emission occurring at the crystal edges demonstrated blinking with a subsecond time interval, which is similar to the previously reported photoluminescence behavior of nanocrystal perovskites. This electroluminescence blinking may provide new insight into the recombination processes depending on the carrier traps and defects of emission layers in perovskite light-emitting devices.

  5. CH3NH3PbCl3 Single Crystals: Inverse Temperature Crystallization and Visible-Blind UV-Photodetector

    KAUST Repository

    Maculan, Giacomo

    2015-09-02

    Single crystals of hybrid perovskites have shown remarkably improved physical properties compared to their polycrystalline film counterparts, underscoring their importance in the further development of advanced semiconductor devices. Here we present a new method of sizeable CH3NH3PbCl3 single crystal growth based on retrograde solubility behavior of hybrid perovskites. We show, for the first time, the energy band structure, charge-carrier recombination and transport properties of single crystal CH3NH3PbCl3. The chloride-based perovskite crystals exhibit trap-state density, charge carriers concentration, mobility and diffusion length comparable with the best quality crystals of methylammonium lead iodide or bromide perovskites reported so far. The high quality of the crystal along with its suitable optical bandgap enabled us to design and build an efficient visible-blind UV-photodetector, demonstrating the potential of this material to be employed in optoelectronic applications.

  6. Team Software Process (TSP) Coach Mentoring Program Guidebook

    Science.gov (United States)

    2009-08-01

    Hodgins, Michelle Jurkouich, Delwyn Kel- logg, Juan Lopez, Andy Oughton, Rafael Salazar, and Jim Van Buren. vi | CMU/SEI-2009-SR-009 1...listed below in bold font ) are areas that should be of particular interest for potential SEI-Certified TSP Coaches and Mentor Coaches, as these are

  7. Preparation and Study of NH3 Gas Sensing Behavior of Fe2O3 Doped ZnO Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    D. R. Patil

    2006-08-01

    Full Text Available The preparation, characterization and gas sensing properties of pure and Fe2O3-ZnO mixed oxide semiconductors have been investigated. The mixed oxides were obtained by mixing ZnO and Fe2O3 in the proportion 1:1, 1:0.5 and 0.5:1. Pure ZnO was observed to be insensitive to NH3 gas. However, mixed oxides (with ZnO: Fe2O3 =1:0.5 were observed to be highly sensitive to ammonia gas. Upon exposure to NH3 gas, the barrier height of Fe2O3-ZnO intergranular regions decreases markedly due to the chemical transformation of Fe2O3 into well conducting ferric ammonium hydroxide leading to a drastic decrease in resistance. The crucial gas response was found to NH3 gas at 3500C and no cross response was observed to other hazardous and polluting gases. The effects of microstructure and doping concentration on the gas response, selectivity, response and recovery of the sensor in the presence of NH3 gas were studied and discussed.

  8. In vitro growth of Brassocattleya orchid hybrid in different concentrations of KNO3, NH4NO3 and benzylaminopurine Cultivo in vitro de Brassocattleya (Orchidaceae em diferentes concentrações de KNO3, NH4NO3 e benzilaminopurina

    Directory of Open Access Journals (Sweden)

    Jean C Cardoso

    2011-09-01

    Full Text Available One of the most important applications of plant tissue culture is mass propagation of ornamental plants. This experiment evaluated the effect of different concentrations of NH4NO3 and KNO3 and BAP on the in vitro growth of orchid hybrid Brassocattleya 'Pastoral'. Seedlings of this orchid hybrid were used as explants and cultivated in medium with mineral salts and vitamins from the MS medium (Murashige & Skoog, 1962, with the macronutrients P, Ca and Mg reduced by half, and with an addition of 25 g L-1 of sucrose, 0.1 g L-1 of myo-inositol and 1.5 g L-1 of activated charcoal. Agar-agar was added (6.5 g L-1 and the pH was adjusted to 5.8. As treatments, four concentrations of the NH4NO3 and KNO3 (2x; 1x; ½ and ¼ MS medium and three concentrations of BAP (0.0; 0.5 and 1.0 mg L-1 were assayed. The multiplication, growth in height, fresh and dry weight and sugar level in dry weight of sprouts were evaluated. There occurred a higher growth in height with 0.25x NH4NO3 and KNO3 salts concentrations of MS medium and higher rate of multiplication with combination of NH4NO3 and KNO3 reduced by half of the MS medium concentration and 1.0 mg L-1 BAP.Entre as maiores aplicações da cultura de tecidos de plantas está a propagação massal de mudas de plantas ornamentais. O objetivo deste trabalho foi avaliar o cultivo in vitro de um híbrido de orquídea Brassocattleya em diferentes concentrações de NH4NO3, KNO3 e BAP. Foram utilizadas sementes do híbrido de orquídea Brassocattleya 'Pastoral' e as plantas foram cultivadas em meio MS com redução pela metade das fontes de P, Mg e Ca e adição de 25 g L-1 de sacarose, 100 mg L-1 de mio-inositol, 1,5 g L-1 de carvão ativo e 6,5 g L-1 de ágar-ágar, sendo o pH ajustado para 5,8. Como tratamentos foram usados quatro concentrações dos sais NH4NO3 e KNO3 (2x; 1x; ½ e ¼ do meio MS e três concentrações de BAP (0,0; 0,5 e 1,0 mg L-1. Avaliou-se a multiplicação, o crescimento em altura, massa fresca

  9. Wintertime indoor air levels of PM10, PM2.5 and PM1 at public places and their contributions to TSP.

    Science.gov (United States)

    Liu, Yangsheng; Chen, Rui; Shen, Xingxing; Mao, Xiaoling

    2004-04-01

    From 26 October 2002 to 8 March 2003, particulate matter (PM) concentrations (total suspended particles [TSP], PM10, PM2.5 and PM1) were measured at 49 public places representing different environments in the urban area of Beijing. The objectives of this study were (1) to characterize the indoor PM concentrations in public places, (2) to evaluate the potential indoor sources and (3) to investigate the contribution of PM10 to TSP and the contributions of PM2.5 and PM1 to PM10. Additionally, The indoor and outdoor particle concentrations in the same type of indoor environment were employed to investigate the I/O level, and comparison was made between I/O levels in different types of indoor environment. Construction activities and traffic condition were the major outdoor sources to influence the indoor particle levels. The contribution of PM10 to TSP was even up to 68.8%, while the contributions of PM2.5 and PM1 to PM10 were not as much as that of PM10 to TSP.

  10. Influence of adhesive bonding on quantity of emissions VOCs

    Directory of Open Access Journals (Sweden)

    Petr Čech

    2008-01-01

    Full Text Available The study deals with the influence of urea-formaldehyde glue and veneered bolstering on technological operation veneering on quantity of emission VOCs (volatile organic compounds.The so-called Volatile Organic Compounds (VOC are among the largest pollution sources of both the internal and external environments.VOC is defined as emission of any organic compound or a mixture thereof, with the exception of methane, whereby the compound exerts the pressure of 0.01 kPa or more at the temperature of 20 °C (293.15 K and reaches the corresponding volatility under the specific conditions of its use and can undergo photochemical reactions with nitrogen oxides when exposed to solar radiation.The effects of VOC upon environment can be described by equation:VOC + NOx + UV radiation + heat = tropospheric ozone (O3.In this work there were tested background working environment in various parts of multi-storeyed press, next was judged emissive charge of veneered device and used glue. We used surface material such as chipboard. We used urea-formaldehyde glue KRONOCOL U300 on technological operation veneering.The VOC emissions from the wooden surfaces with or without finishing were tested in the Equipment for VOC Measuring with a small-space chamber. This equipment was installed in and made available by the Institute of Furniture, Design and Habitation. The small-space chamber is suitable for testing small parts of wood products. The device equipped with small-chamber satisfies all conditions mandated in the standard ENV 13 419 DIN -V-ENV 13 419 ”Determination of the emissions of Volatile organic compounds”.The VOC emissions were collected in columns with sorbent Tenax TA. We analyzed the columns with the VOC emissions by: the gas chromatography in conjunction with mass spectrometer and Direct Thermal Desorption.

  11. PEMANFAATAN TEKNOLOGI GOOGLE MAPS UNTUK PENYELESAIAN ONLINE TRAVELLING SALESMAN PROBLEM (TSP BERBASIS GEOGRAFIS DENGAN MENGGUNAKAN ALGORITMA HEURISTIK

    Directory of Open Access Journals (Sweden)

    Wahyudi Agustiono

    2010-07-01

    Full Text Available Travelling Salesman Problem (TSP adalah salah satu metode klasik dalam proses pemecahan masalah optimasi dan penemuan rute terpendek dari sebuah rute perjalanan yang melewati beberapa titik lokasi. Oleh karena kehandalan metode ini banyak sekali algoritma dan metode optimasi yang mencoba memecahkan TSP dalam banyak penelitian. Sebagin besar hasil dari rangkaian ujicoba tersebut berupa kombinasi teroptimal dari rangkaian perjalanan salesman yang umumnya digambarkan dalam sebuah graph. Namun belum banyak penelitian yang menerapkan TSP pada data spasial atau geografis seperti Google Maps yang dapat memberikan representasi nyata permasalahan TSP dalam menemukan rute perjalanan melewati titik-titik wilayah di muka bumi. Dibandingkan dengan representasi graph, Google Maps memiliki kemampuan tidak sekedar menampilkan rute perjalanan akan tetapi juga dapat menyajikan informasi yang lebih komprehensif, interaktif dan faktual. Penelitian ini bertujuan untuk menerapkan metode TSP pada layanan data spasial sehingga akan dihasilkan visualisasi secara riil dari alternatif rute perjalanan salesman. Sebagai basis dari data spasial, penelitian ini memanfaatkan Google Maps Mashup untuk mendapatkan informasi rute yang lebih aktual, interaktif, dan komprehensif.

  12. Quantifying local traffic contributions to NO2 and NH3 concentrations in natural habitats

    International Nuclear Information System (INIS)

    Gadsdon, Sally R.; Power, Sally A.

    2009-01-01

    NO 2 and NH 3 concentrations were measured across a Special Area for Conservation in southern England, at varying distances from the local road network. Exceedances of the critical levels for these pollutants were recorded at nearly all roadside locations, extending up to 20 m away from roads at some sites. Further, paired measurements of NH 3 and NO 2 concentrations revealed differences between ground and tree canopy levels. At 'background' sites, away from the direct influence of roads, concentrations were higher within tree canopies than at ground level; the reverse pattern was, however, seen at roadside locations. Calculations of pollutant deposition rates showed that nitrogen inputs are dominated by NH 3 at roadside sites. This study demonstrates that local traffic emissions contribute substantially to the exceedance of critical levels and critical loads, and suggests that on-site monitoring is needed for sites of nature conservation value which are in close proximity to local transport routes. - NO x and NH 3 concentrations exceed vegetation critical levels up to 20 m from roadsides, both at ground level and in tree canopies.

  13. An Extension of the Lin-Kernighan-Helsgaun TSP Solver for Constrained Traveling Salesman and Vehicle Routing Problems

    DEFF Research Database (Denmark)

    Helsgaun, Keld

    This report describes the implementation of an extension of the Lin-Kernighan-Helsgaun TSP solver for solving constrained traveling salesman and vehicle routing problems. The extension, which is called LKH-3, is able to solve a variety of well-known problems, including the sequential ordering...... problem (SOP), the traveling repairman problem (TRP), variants of the multiple travel-ing salesman problem (mTSP), as well as vehicle routing problems (VRPs) with capacity, time windows, pickup-and-delivery and distance constraints. The implementation of LKH-3 builds on the idea of transforming...... the problems into standard symmetric traveling salesman problems and handling constraints by means of penalty functions. Extensive testing on benchmark instances from the literature has shown that LKH-3 is effective. Best known solutions are often obtained, and in some cases, new best solutions are found...

  14. A Highly Selective Room Temperature NH3 Gas Sensor based on Nanocrystalline a-Fe2O3

    Directory of Open Access Journals (Sweden)

    Priyanka A. PATIL

    2017-05-01

    Full Text Available Nanocrystalline a-Fe2O3 powder was synthesized by simple, inexpensive sol-gel method. The obtained powder was calcined at 700 0C in air atmosphere for 2 hours. The structural and morphological properties of calcined powder were studied by X-ray diffraction (XRD and Field Emission Scanning Electron Microscopy (FESEM respectively. Thermal properties of dried gel were studied by Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC. The XRD pattern of the powder confirmed the a-Fe2O3 (hematite phase of iron oxide with average crystalline size of 30.87 nm calculated from Scherrer equation. The FESEM images showed uniform wormlike morphology of a-Fe2O3 powder. TGA result indicated that a-Fe2O3 is thermodynamically stable. Room temperature NH3 sensing characteristics of a-Fe2O3 were studied for various concentration levels (250-2500 ppm of NH3 at various humid conditions. The sensor based on a-Fe2O3 exhibited good selectivity and excellent sensitivity (S=92 towards 1000 ppm of NH3 with quick response of 4 sec and fast recovery of 9 sec. Room temperature sensing mechanism is also discussed.

  15. Thermal properties and phase transition in the fluoride, (NH{sub 4}){sub 3}SnF{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Kartashev, A.V. [Kirensky Institute of Physics, Siberian Department of the Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Astafijev Krasnoyarsk State Pedagogical University, 660049 Krasnoyarsk (Russian Federation); Gorev, M.V. [Kirensky Institute of Physics, Siberian Department of the Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Institute of Engineering Physics and Radio Electronics, Siberian State University, 660074 Krasnoyarsk (Russian Federation); Bogdanov, E.V. [Kirensky Institute of Physics, Siberian Department of the Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Krasnoyarsk State Agrarian University, 660049 Krasnoyarsk (Russian Federation); Flerov, I.N. [Kirensky Institute of Physics, Siberian Department of the Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Institute of Engineering Physics and Radio Electronics, Siberian State University, 660074 Krasnoyarsk (Russian Federation); Laptash, N.M. [Institute of Chemistry, Far Eastern Department of the Russian Academy of Sciences, 690022 Vladivostok (Russian Federation)

    2016-05-15

    Calorimetric, dilatometric and differential thermal analysis studies were performed on (NH{sub 4}){sub 3}SnF{sub 7} for a wide range of temperatures and pressures. Large entropy (δS{sub 0}=22 J/mol K) and elastic deformation (δ(ΔV/V){sub 0}=0.89%) jumps have proven that the Pa-3↔Pm-3m phase transition is a strong first order structural transformation. A total entropy change of ΔS{sub 0}=32.5 J/mol K is characteristic for the order–disorder phase transition, and is equal to the sum of entropy changes in the related material, (NH{sub 4}){sub 3}TiF{sub 7}, undergoing transformation between the two cubic phases through the intermediate phases. Hydrostatic pressure decreases the stability of the high temperature Pm-3m phase in (NH{sub 4}){sub 3}SnF{sub 7}, contrary to (NH{sub 4}){sub 3}TiF{sub 7}, characterised by a negative baric coefficient. The effect of experimental conditions on the chemical stability of (NH{sub 4}){sub 3}SnF{sub 7} was observed. - Graphical abstract: Strong first order structural transformation Pa-3↔Pm-3m in (NH{sub 4}){sub 3}SnF{sub 7} is associated with very large total entropy change of ΔS{sub 0}=32.5 J/mol K characteristic for the ordering processes and equal to the sum of entropy changes in the related (NH{sub 4}){sub 3}TiF{sub 7} undergoing transformation between the same two cubic phases through the intermediate phases. - Highlights: • (NH{sub 4}){sub 3}SnF{sub 7} undergoes strong first order Pa-3↔Pm-3m phase transition. • Anomalous behaviour of ΔC{sub p} and ΔV/V exists far below phase transition temperature. • Structural distortions are accompanied by huge total entropy change ΔS≈Rln50. • High pressure strongly increases the stability of Pa-3 phase in (NH{sub 4}){sub 3}SnF{sub 7}. • Entropy of the Pa-3↔Pm-3m phase transition does not depend on pressure.

  16. Effect of Different CH3NH3PbI3 Morphologies on Photovoltaic Properties of Perovskite Solar Cells

    Science.gov (United States)

    Chen, Lung-Chien; Lee, Kuan-Lin; Wu, Wen-Ti; Hsu, Chien-Feng; Tseng, Zong-Liang; Sun, Xiao Hong; Kao, Yu-Ting

    2018-05-01

    In this study, the perovskite layers were prepared by two-step wet process with different CH3NH3I (MAI) concentrations. The cell structure was glass/FTO/TiO2-mesoporous/CH3NH3PbI3 (MAPbI3)/spiro-OMeTAD/Ag. The MAPbI3 perovskite films were prepared using high and low MAI concentrations in a two-step process. The perovskite films were optimized at different spin coating speed and different annealing temperatures to enhance the power conversion efficiency (PCE) of perovskite solar cells. The PCE of the resulting device based on the different perovskite morphologies was discussed. The PCE of the best cell was up to 17.42%, open circuit voltage of 0.97 V, short current density of 24.06 mA/cm2, and fill factor of 0.747.

  17. The matricellular protein TSP1 promotes human and mouse endothelial cell senescence through CD47 and Nox1.

    Science.gov (United States)

    Meijles, Daniel N; Sahoo, Sanghamitra; Al Ghouleh, Imad; Amaral, Jefferson H; Bienes-Martinez, Raquel; Knupp, Heather E; Attaran, Shireen; Sembrat, John C; Nouraie, Seyed M; Rojas, Mauricio M; Novelli, Enrico M; Gladwin, Mark T; Isenberg, Jeffrey S; Cifuentes-Pagano, Eugenia; Pagano, Patrick J

    2017-10-17

    Senescent cells withdraw from the cell cycle and do not proliferate. The prevalence of senescent compared to normally functioning parenchymal cells increases with age, impairing tissue and organ homeostasis. A contentious principle governing this process has been the redox theory of aging. We linked matricellular protein thrombospondin 1 (TSP1) and its receptor CD47 to the activation of NADPH oxidase 1 (Nox1), but not of the other closely related Nox isoforms, and associated oxidative stress, and to senescence in human cells and aged tissue. In human endothelial cells, TSP1 promoted senescence and attenuated cell cycle progression and proliferation. At the molecular level, TSP1 increased Nox1-dependent generation of reactive oxygen species (ROS), leading to the increased abundance of the transcription factor p53. p53 mediated a DNA damage response that led to senescence through Rb and p21 cip , both of which inhibit cell cycle progression. Nox1 inhibition blocked the ability of TSP1 to increase p53 nuclear localization and p21 cip abundance and its ability to promote senescence. Mice lacking TSP1 showed decreases in ROS production, p21 cip expression, p53 activity, and aging-induced senescence. Conversely, lung tissue from aging humans displayed increases in the abundance of vascular TSP1, Nox1, p53, and p21 cip Finally, genetic ablation or pharmacological blockade of Nox1 in human endothelial cells attenuated TSP1-mediated ROS generation, restored cell cycle progression, and protected against senescence. Together, our results provide insights into the functional interplay between TSP1 and Nox1 in the regulation of endothelial senescence and suggest potential targets for controlling the aging process at the molecular level. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  18. NH{sub 3} adsorption on the Lewis and Bronsted acid sites of MoO{sub 3} (0 1 0) surface: A cluster DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Zhifeng [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Fan, Junyan [Foundation Department, Shanxi Police Academy, No. 27 Second Section of Old Jinci Road, Taiyuan 030021, Shanxi (China); Zuo, Zhijun [Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Li, Zhe, E-mail: lizhe@tyut.edu.cn [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Zhang, Jinshan [College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China)

    2014-01-01

    The adsorption of NH{sub 3} on the Lewis and Bronsted acid sites of MoO{sub 3} (0 1 0) surface has been investigated based on the density functional theory (DFT) method using the clusters models. The calculated results indicate that NH{sub 3} could strongly adsorb on both the Lewis and Bronsted acid sites in the form of NH{sub 3} species and NH{sub 4}{sup +} respectively, whereas the adsorption on the Lewis acid site is found to be more favorable energetically than that on the Bronsted acid site. For the Lewis acid site Mulliken population analysis shows a donation of lone pairs from NH{sub 3} to the surface and activation of N–H bond. The overlaps of N-s, N-p and Mo-d orbitals suggest the strong interaction between N and Mo atoms. For the Bronsted acid site N–H bond is also activated by the formation of NH{sub 4}{sup +} species. The hybridizations between H and O atoms as well as N and H atoms are the major reasons for strong chemical adsorption of NH{sub 3} and the existence of NH{sub 4}{sup +} species, which partly attributed to the presence of N–H… O hydrogen bonds. Furthermore, the formation of a second Lewis acid site at adjacent or diagonal site results in slight changes of adsorption stability, structural changes and charge redistributions, suggesting its small influence on NH{sub 3} adsorption.

  19. The spatial distribution of C2, C3, and NH in comet 2P/Encke

    International Nuclear Information System (INIS)

    Dorman, Garrett; Pierce, Donna M.; Cochran, Anita L.

    2013-01-01

    We examine the spatial distribution of C 2 , C 3 , and NH radicals in the coma of comet Encke in order to understand their abundances and distributions in the coma. The observations were obtained from 2003 October 22-24, using the 2.7 m telescope at McDonald Observatory. Building on our original study of CN and OH, we have used our modified version of the vectorial model, which treats the coma as one large cone, in order to reproduce Encke's highly aspherical and asymmetric coma. Our results suggest that NH can be explained by the photodissociation of NH 2 , assuming that NH 2 is produced rapidly from NH 3 in the innermost coma. Our modeling of C 2 and C 3 suggests a multi-generational photodissociation process may be required for their production. Using the results of our previous study, we also obtain abundance ratios with respect to OH and CN. Overall, we find that Encke exhibits typical carbon-chain abundances, and the results are consistent with other studies of comet Encke.

  20. The Spatial Distribution of C2, C3, and NH in Comet 2P/Encke

    Science.gov (United States)

    Dorman, Garrett; Pierce, Donna M.; Cochran, Anita L.

    2013-12-01

    We examine the spatial distribution of C2, C3, and NH radicals in the coma of comet Encke in order to understand their abundances and distributions in the coma. The observations were obtained from 2003 October 22-24, using the 2.7 m telescope at McDonald Observatory. Building on our original study of CN and OH, we have used our modified version of the vectorial model, which treats the coma as one large cone, in order to reproduce Encke's highly aspherical and asymmetric coma. Our results suggest that NH can be explained by the photodissociation of NH2, assuming that NH2 is produced rapidly from NH3 in the innermost coma. Our modeling of C2 and C3 suggests a multi-generational photodissociation process may be required for their production. Using the results of our previous study, we also obtain abundance ratios with respect to OH and CN. Overall, we find that Encke exhibits typical carbon-chain abundances, and the results are consistent with other studies of comet Encke.

  1. Deuterium isotope effects on the dipole moment and polarizability of HCl and NH3

    International Nuclear Information System (INIS)

    Scher, C.; Ravid, B.; Halevi, E.A.

    1982-01-01

    A previously described adaptation of the conventional Debye procedure for the direct determination of small dipole moment and polarizability differences between two polar gases is applied to the isotopic pairs DCl-HCl and ND 3 -NH 3 . The dipole moment difference obtained for the first isotopic pair, by using the Debye-Van Vleck equation for electric susceptibility, μ(DCl) - μ(HCl) = 0.005 5 +/- 0.0002 D, is consistent with published spectroscopically determined values of μ 00 (DCl) and μ 00 (HCl), while that obtained by using the classical Debye equation is not. For the second pair, use of the Debye-Van Vleck equation, along with a correction for thermal population of vibrationally excited levels, is shown to be essential and yields μ(ND) 3 - μ(NH 3 ) = +0.013 5 +/- 0.001 D and α(ND 3 ) - α(NH 3 ) = -(2.2 +/- 1.7) x 10 -26 cm 3

  2. Using Low Temperature Photoluminescence Spectroscopy to Investigate CH3NH3PbI3 Hybrid Perovskite Degradation

    Directory of Open Access Journals (Sweden)

    Khaoula Jemli

    2016-07-01

    Full Text Available Investigating the stability and evaluating the quality of the CH3NH3PbI3 perovskite structures is quite critical both to the design and fabrication of high-performance perovskite devices and to fundamental studies of the photophysics of the excitons. In particular, it is known that, under ambient conditions, CH3NH3PbI3 degrades producing some PbI2. We show here that low temperature Photoluminescence (PL spectroscopy is a powerful tool to detect PbI2 traces in hybrid perovskite layers and single crystals. Because PL spectroscopy is a signal detection method on a black background, small PbI2 traces can be detected, when other methods currently used at room temperature fail. Our study highlights the extremely high stability of the single crystals compared to the thin layers and defects and grain boundaries are thought to play an important role in the degradation mechanism.

  3. Secondary side TSP deposit buildup: lab test investigation focused on electrokinetic considerations

    International Nuclear Information System (INIS)

    Barale, M.; Guillodo, M.; Foucault, M.; Ryckelynck, N.; Clinard, M-H.; Chahma, F.; Brun, C.; Corredera, G.

    2010-01-01

    Deposit buildup which caused the clogging of the 'foils' of the upper tube-support-plates (TSP) inside a PWR steam generator of French NPPs in 2006 presents certain similarities with deposits observed in lab tests performed in secondary coolant chemistry at the Technical Centre of AREVA NP in 2002. The mechanism of TSP clogging seems not to present obvious phenomenological links with the fouling of the free span of SG since deposits buildup is quite uniform and is currently related to a surface boiling effect due to the surface heat flux. A specific mechanism could account for TSP clogging. In particular, electrokinetic effects were investigated by EDF-CEIDRE and AREVA NP SAS in the framework of a lab test program started in 2007. The electrokinetic approach is to consider that the coupling of local hydrodynamic and surface electrochemistry could lead to the formation of a very localized and heterogeneous deposit at the leading edge between both TSP and SG tubing material. Electrokinetic effects can lead to the oxidation and/or the precipitation of ferrous ions and to a variation of the electrokinetic potential which can produce strong attraction of iron oxide colloids. These electrokinetic effects are dependent of the T/H and local hydrodynamic conditions and surface electrochemistry explaining. The objective of this EDF-AREVA lab test program is to investigate the role of secondary chemistry coolant (pH, DH, N 2 H 4 , amine, redox) and of the nature of materials (SS, Ni base alloy) on deposit buildup. Properties of oxide surface and zeta potential of oxidized metallic materials have been also determined at temperature to understand their potential contribution on mechanism of TSP clogging in secondary side chemistry coolant. In this paper, a set of specific experiments carried out in this frame have been presented and discussed, paying particular attention to the effects of electrokinetic considerations and surface charges at oxide-solution interfaces

  4. Secondary side TSP deposit buildup: lab test investigation focused on electrokinetic considerations

    Energy Technology Data Exchange (ETDEWEB)

    Barale, M.; Guillodo, M.; Foucault, M., E-mail: Morgan.Barale@areva.com [AREVA NP SAS, Technical Centre, Le Creusot (France); Ryckelynck, N.; Clinard, M-H.; Chahma, F.; Brun, C. [AREVA NP SAS, Chemistry and Radiochemistry Group, Paris (France); Corredera, G. [Electricite de France, Centre d' Expertise et d' Inspection dans les domaines de la Realisation et de l' Exploitation, Saint-Denis (France)

    2010-07-01

    Deposit buildup which caused the clogging of the 'foils' of the upper tube-support-plates (TSP) inside a PWR steam generator of French NPPs in 2006 presents certain similarities with deposits observed in lab tests performed in secondary coolant chemistry at the Technical Centre of AREVA NP in 2002. The mechanism of TSP clogging seems not to present obvious phenomenological links with the fouling of the free span of SG since deposits buildup is quite uniform and is currently related to a surface boiling effect due to the surface heat flux. A specific mechanism could account for TSP clogging. In particular, electrokinetic effects were investigated by EDF-CEIDRE and AREVA NP SAS in the framework of a lab test program started in 2007. The electrokinetic approach is to consider that the coupling of local hydrodynamic and surface electrochemistry could lead to the formation of a very localized and heterogeneous deposit at the leading edge between both TSP and SG tubing material. Electrokinetic effects can lead to the oxidation and/or the precipitation of ferrous ions and to a variation of the electrokinetic potential which can produce strong attraction of iron oxide colloids. These electrokinetic effects are dependent of the T/H and local hydrodynamic conditions and surface electrochemistry explaining. The objective of this EDF-AREVA lab test program is to investigate the role of secondary chemistry coolant (pH, DH, N{sub 2}H{sub 4}, amine, redox) and of the nature of materials (SS, Ni base alloy) on deposit buildup. Properties of oxide surface and zeta potential of oxidized metallic materials have been also determined at temperature to understand their potential contribution on mechanism of TSP clogging in secondary side chemistry coolant. In this paper, a set of specific experiments carried out in this frame have been presented and discussed, paying particular attention to the effects of electrokinetic considerations and surface charges at oxide

  5. Interplay between organic cations and inorganic framework and incommensurability in hybrid lead-halide perovskite CH3NH3PbBr3

    Science.gov (United States)

    Guo, Yinsheng; Yaffe, Omer; Paley, Daniel W.; Beecher, Alexander N.; Hull, Trevor D.; Szpak, Guilherme; Owen, Jonathan S.; Brus, Louis E.; Pimenta, Marcos A.

    2017-09-01

    Organic-inorganic coupling in the hybrid lead-halide perovskite is a central issue in rationalizing the outstanding photovoltaic performance of these emerging materials. Here, we compare and contrast the evolution of the structure and dynamics of hybrid CH3NH3PbBr3 and inorganic CsPbBr3 lead-halide perovskites with temperature, using Raman spectroscopy and single-crystal x-ray diffraction. Results reveal a stark contrast between their order-disorder transitions, which are abrupt for the hybrid whereas smooth for the inorganic perovskite. X-ray diffraction observes an intermediate incommensurate phase between the ordered and the disordered phases in CH3NH3PbBr3 . Low-frequency Raman scattering captures the appearance of a sharp soft mode in the incommensurate phase, ascribed to the theoretically predicted amplitudon mode. Our work highlights the interaction between the structural dynamics of organic cation CH3NH3+ and the lead-halide framework, and unravels the competition between tendencies for the organic and inorganic moieties to minimize energy in the incommensurate phase of the hybrid perovskite structure.

  6. Characteristics of NH4+ and NO3- fluxes in tea (Camellia sinensis) roots measured by scanning ion-selective electrode technique.

    Science.gov (United States)

    Ruan, Li; Wei, Kang; Wang, Liyuan; Cheng, Hao; Zhang, Fen; Wu, Liyun; Bai, Peixian; Zhang, Chengcai

    2016-12-05

    As a vital beverage crop, tea has been extensively planted in tropical and subtropical regions. Nitrogen (N) levels and forms are closely related to tea quality. Based on different N levels and forms, we studied changes in NO 3 - and NH 4 + fluxes in tea roots utilizing scanning ion-selective electrode technique. Our results showed that under both single and mixed N forms, influx rates of NO 3 - were much lower than those of NH 4 + , suggesting a preference for NH 4 + in tea. With the increase in N concentration, the influx rate of NO 3 - increased more than that of NH 4 + . The NH 4 + influx rates in a solution without NO 3 - were much higher than those in a solution with NO 3 - , while the NO 3 - influx rates in a solution without NH 4 + were much lower than those in a solution with NH 4 + . We concluded that (1) tea roots showed a preference for NH 4 + , (2) presence of NO 3 - had a negative effect on NH 4 + influx, and (3) NH 4 + had a positive effect on NO 3 - influx. Our findings not only may help advance hydroponic tea experiments but also may be used to develop efficient fertilization protocols for soil-grown tea in the future.

  7. 3D-CFD analysis of diffusion and emission of VOCs in a FLEC cavity.

    Science.gov (United States)

    Zhu, Q; Kato, S; Murakami, S; Ito, K

    2007-06-01

    This study is performed as a part of research that examines the emission and diffusion characteristics of volatile organic compounds (VOCs) from indoor building materials. In this paper, the flow field and the emission field of VOCs from the surface of building materials in a Field and Laboratory Emission Cell (FLEC) cavity are examined by 3D Computational Fluid Dynamics (CFD) analysis. The flow field within the FLEC cavity is laminar. With a total flow of 250 ml/min, the air velocity near the test material surface ranges from 0.1 to 4.5 cm/s. Three types of emission from building materials are studied here: (i) emission phenomena controlled by internal diffusion, (ii) emission phenomena controlled by external diffusion, and (iii) emission phenomena controlled by mixed diffusion (internal + external diffusion). In the case of internal diffusion material, with respect to the concentration distribution in the cavity, the local VOC emission rate becomes uniform and the FLEC works well. However, in the case of evaporation type (external diffusion) material, or mixed type materials (internal + external diffusion) when the resistance to transporting VOCs in the material is small, the FLEC is not suitable for emission testing because of the thin FLEC cavity. In this case, the mean emission rate is restricted to a small value, since the VOC concentration in the cavity rises to the same value as the surface concentration through molecular diffusion within the thin cavity, and the concentration gradient normal to the surface becomes small. The diffusion field and emission rate depend on the cavity concentration and on the Loading Factor. That is, when the testing material surface in the cavity is partially sealed to decrease the Loading Factor, the emission rate become higher with the decrease in the exposed area of the testing material. The flow field and diffusion field within the FLEC cavity are investigated by CFD method. After presenting a summary of the velocity

  8. Analysis of Sidestream Smoke VOCs and Characterization of their Odor Profiles by VOC Preconcentrator-GC-O Techniques

    Directory of Open Access Journals (Sweden)

    Higashi N

    2014-12-01

    Full Text Available Various techniques have been employed in the analysis of volatile organic compounds (VOCs. However, these techniques are insufficient for the precise analysis of tobacco smoke VOCs because of the complexity of the operating system, system instability, or poor sensitivity. To overcome these problems, a combined system of VOC preconcentrator, gas chromatograph, and olfactometer has been developed. The performance of this new system was evaluated in the analysis of VOCs in tobacco smoke and applied to the odor profiling of sidestream smoke (SSS that has not been sufficiently investigated in the past.

  9. Appropriate NH4+: NO3- ratio improves low light tolerance of mini Chinese cabbage seedlings.

    Science.gov (United States)

    Hu, Linli; Liao, Weibiao; Dawuda, Mohammed Mujitaba; Yu, Jihua; Lv, Jian

    2017-01-23

    In northwest of China, mini Chinese cabbage (Brassica pekinensis) is highly valued by consumers, and is widely cultivated during winter in solar-greenhouses where low light (LL) fluence (between 85 and 150 μmol m -2 s -1 in day) is a major abiotic stress factor limiting plant growth and crop productivity. The mechanisms with which various NH 4 + : NO 3 - ratios affected growth and photosynthesis of mini Chinese cabbage under normal (200 μmol m -2 s -1 ) and low (100 μmol m -2 s -1 ) light conditions was investigated. The four solutions with different ratios of NH 4 + : NO 3 - applied were 0:100, 10:90, 15:85 and 25:75 with the set up in a glasshouse in hydroponic culture. The most appropriate NH 4 + : NO 3 - ratio that improved the tolerance of mini Chinese cabbage seedlings to LL was found in our current study. Under low light, the application of NH 4 + : NO 3 - (10:90) significantly stimulated growth compared to only NO 3 - by increasing leaf area, canopy spread, biomass accumulation, and net photosynthetic rate. The increase in net photosynthetic rate was associated with an increase in: 1) maximum and effective quantum yield of PSII; 2) activities of Calvin cycle enzymes; and 3) levels of mRNA relative expression of several genes involved in Calvin cycle. In addition, glucose, fructose, sucrose, starch and total carbohydrate, which are the products of CO 2 assimilation, accumulated most in the cabbage leaves that were supplied with NH 4 + : NO 3 - (10:90) under LL condition. Low light reduced the carbohydrate: nitrogen (C: N) ratio while the application of NH 4 + : NO 3 - (10:90) alleviated the negative effect of LL on C: N ratio mainly by increasing total carbohydrate contents. The application of NH 4 + :NO 3 - (10:90) increased rbcL, rbcS, FBA, FBPase and TK expression and/or activities, enhanced photosynthesis, carbohydrate accumulation and improved the tolerance of mini Chinese cabbage seedlings to LL. The results of this study would provide

  10. Alloyed Ni-Fe nanoparticles as catalysts for NH3 decomposition

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chakraborty, Debasish; Chorkendorff, Ib

    2012-01-01

    A rational design approach was used to develop an alloyed Ni-Fe/Al2O3 catalyst for decomposition of ammonia. The dependence of the catalytic activity is tested as a function of the Ni-to-Fe ratio, the type of Ni-Fe alloy phase, the metal loading and the type of oxide support. In the tests with high...... temperatures and a low NH3-to-H2 ratio, the catalytic activity of the best Ni-Fe/Al2O3 catalyst was found to be comparable or even better to that of a more expensive Ru-based catalyst. Small Ni-Fe nanoparticle sizes are crucial for an optimal overall NH3 conversion because of a structural effect favoring...

  11. Hexamethylenetetramine-mediated growth of grain-boundary-passivation CH3NH3PbI3 for highly reproducible and stable perovskite solar cells

    Science.gov (United States)

    Zheng, Yan-Zhen; Li, Xi-Tao; Zhao, Er-Fei; Lv, Xin-Ding; Meng, Fan-Li; Peng, Chao; Lai, Xue-Sen; Huang, Meilan; Cao, Guozhong; Tao, Xia; Chen, Jian-Feng

    2018-02-01

    Simultaneously achieving the long-term device stability and reproducibility has proven challenging in perovskite solar cells because solution-processing produced perovskite film with grain boundary is sensitive to moisture. Herein, we develop a hexamethylenetetramine (HMTA)-mediated one-step solution-processing deposition strategy that leads to the formation of high-purity and grain-boundary-passivation CH3NH3PbI3 film and thereby advances cell optoelectronic performance. Through morphological and structural characterizations and theoretical calculations, we demonstrate that HMTA fully occupies the moisture-exposed surface to build a bridge across grain boundary and coordinates with Pb ions to inhibit the formation of detrimental PbI2. Such HMTA-mediated grown CH3NH3PbI3 films achieves a decent augmentation of power conversion efficiency (PCE) from 12.70% to 17.87%. A full coverage of PbI2-free CH3NH3PbI3 surface on ZnO also boosts the device's stability and reproducibility.

  12. The Recombination Mechanism and True Green Amplified Spontaneous Emission in CH3NH3PbBr3 Perovskite

    KAUST Repository

    Priante, Davide

    2015-01-01

    . M. Bakr, and B. S. Ooi, "The recombination mechanisms leading to amplified spontaneous emission at the true-green wavelength in CH3NH3PbBr3 perovskites", Applied Physics Letters, 106, 081902, 2015. DOI: 10.1063/1.4913463

  13. Solid-phase synthesis of NH-1,2,3-triazoles using 4,4′- bismethoxybenzhydryl azide

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil O'Hanlon; Le Quement, Sebastian Thordal; Nielsen, Thomas Eiland

    2014-01-01

    Readily available 4,4′-bismethoxybenzhydryl azide was found to be a useful building block for the synthesis of NH-1,2,3-triazoles through copper(I)-catalyzed cycloaddition reactions with solid-supported terminal alkynes, followed by acid-mediated deprotection. Peptide-containing NH-1,2,3-triazole...

  14. Optical constants of CH3NH3PbBr3 perovskite thin films measured by spectroscopic ellipsometry

    KAUST Repository

    Alias, Mohd Sharizal; Dursun, Ibrahim; Saidaminov, Makhsud I.; Diallo, Elhadj Marwane; Mishra, Pawan; Ng, Tien Khee; Bakr, Osman; Ooi, Boon S.

    2016-01-01

    function) of CH3NH3PbBr3 perovskite thin films using spectroscopic ellipsometry. Due to the existence of voids, the refractive index of the thin films is around 8% less than the single crystals counterpart. The energy bandgap is around 2.309 eV as obtained

  15. Corrosion and solubility in a TSP-buffered chemical environment following a loss of coolant accident: Part 3—Calcium

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Sterling; Ali, Amir; LaBrier, Daniel [Department of Nuclear Engineering, University of New Mexico (United States); Blandford, Edward D, E-mail: edb@unm.edu [Department of Nuclear Engineering, University of New Mexico (United States); Howe, Kerry [Department of Civil Engineering, University of New Mexico (United States)

    2016-04-15

    Highlights: • Calcium leaching from NUKON fiberglass in borated TSP-buffered solution is independent of the level of fiberglass destruction. • The initial calcium release rate and the maximum calcium concentration increases with increased fiber concentration. • The calcium release in solution has a repeatable pattern of four distinct regions (prompt release, metastable, autocatalytic drop, and stable region) for all experiments. • Magnesium plays a significant role in initiating calcium precipitation in TSP-buffered environment. • Head loss through multi-constituents debris beds was found to increase progressively in all calcium concentration regions. - Abstract: Calcium that leaches from damaged or destroyed NUKON fiberglass in containment post a loss of coolant accident (LOCA) could lead to the formation of chemical precipitates. These precipitates could be filtered through the accumulated fibrous debris on the sump screen and compromising the emergency core cooling system (ECCS) sump pump performance. Reduced-scale leaching experiments were conducted on three solution inventory scales—bench (0.5 L), vertical column (31.5 L), and tank (1136 L) using three different flow conditions, and fiberglass concentrations (1.18–8 g/L) to investigate calcium release from NUKON fiber. All experiments were conducted in simulated post-LOCA water chemistry. (∼220 mM boric acid with ∼5.8 mM trisodium phosphate (TSP) buffer). Prior to the leaching tests, a preliminary experiment was carried out on the bench scale to determine the effect of the fiber preparation (unaltered and blended) method on calcium leaching. Results indicate that the extent of fiberglass destruction does not affect the amount of calcium released from fiberglass. Long-term calcium leach testing at constant temperature (80 °C) in borated TSP-buffered solution had repeatable behavior on all solution scales for different fiberglass concentrations. The calcium-leaching pattern can be divided into

  16. Removal of VOCs by hybrid electron beam reactor with catalyst bed

    International Nuclear Information System (INIS)

    Kim, Jinkyu; Han, Bumsoo; Kim, Yuri; Lee, J.H.; Park, C.R.; Kim, J.C.; Kim, J.C.; Kim, K.J.

    2004-01-01

    Electron beam decomposition of volatile organic compounds (VOCs) was studied in order to obtain information for developing effective treatment method of off-gases from industries. We have examined the combination of electron beam and catalyst honeycomb which is either 1% platinum based or ceramic honeycomb- based aluminum oxide, using a hybrid reactor in order to improve removal efficiency and CO 2 formation; and to suppress undesirable by-product formation e.g. O 3 , aerosol, H x C y. , and tar. The experiments were conducted using a pilot-scale treatment system (maximum capacity; 1800 N m 3 /h) that fitted the field size to scale up from the traditional laboratory scale system for VOC removal with electron beam irradiation. Toluene was selected as a typical VOC that was irradiated to investigate product formation, effect of ceramic and catalyst, and factors effecting overall efficiency of degradation. Styrene was selected as the most odorous compound among the VOCs of interest. It was found that VOCs could be destroyed more effectively using a hybrid system with catalyst bed than with electron beam irradiation only

  17. Observations of HC5N and NH3 in Taurus

    International Nuclear Information System (INIS)

    Myers, P.C.; Ho, P.T.P.; Benson, P.J.

    1979-01-01

    Observations of HC 5 N lines toward TMC-2 indicate that it is a small (Lapprox.0.1 pc), dense (napprox.4 x 10 4 cm -3 ), low-mass (Mapprox.1 M/sub sun/) fragment in the Taurus complex, with velocity dispersion at the emission peak only about twice thermal (Δvapprox.0.2 km s -1 ). The HC 5 N emission region in TMC-2 has roughly half the projected area of that in TMC-1, and is more round than filamentary. The HC 5 N and NH 3 emission regions in TMC-2 are coincident, with N (HC 5 N)/N (NH 3 ) approx.0.1. The line width is much smaller than the free-fall width; the deduced values of L, n, and T satisfy the virial-theorem requirement for stable equilibrium. The temporary equilibrium of such fragments may serve to lengthen the time scales for formation of low-mass stars and long-chain molecules

  18. On-road measurement of NH3 emissions from gasoline and diesel passenger cars during real world driving conditions

    Science.gov (United States)

    Suarez-Bertoa, Ricardo; Mendoza-Villafuerte, Pablo; Riccobono, Francesco; Vojtisek, Michal; Pechout, Martin; Perujo, Adolfo; Astorga, Covadonga

    2017-10-01

    NH3 is a precursor of PM2.5 which deteriorates urban air quality, affects human health and impacts the global radiation budget. Since vehicles are important sources of NH3 in urban areas, we have satisfactorily studied the possibility of measuring NH3 emissions from gasoline and SCR-equipped diesel light-duty vehicles during real driving on-road operation using a portable FTIR. The performance of the portable FTIR resulted to be comparable to that of a laboratory-based FTIR during a series of experiments performed in the Vehicle Emission Laboratory (VELA) using the World-harmonized Light-duty Test Cycle (WLTC). Higher on-road NH3 emission factors were obtained for the gasoline vehicle than for the diesel. High NOx emissions were measured from the diesel vehicle, indicating a low efficiency of the DeNOx system, SCR. On-road NH3 emission factors were ∼2 times lower than during the laboratory tests at 23 °C for both vehiclesNH3 emissions were not observed for the diesel vehicle during cold start operation. However, NH3 cold start emissions from the gasoline vehicle were up to 2 orders of magnitude higher than during the entire road trips, ranging from 45 to 134 mg km-1. Cold start emissions are of paramount importance as they commonly take place in urban areas. Hence, future urban reductions in PM2.5 might need to take into consideration the introduction of NH3 emissions limits for passenger cars.

  19. Mechanical response of CH3NH3PbI3 nanowires

    Science.gov (United States)

    Ćirić, L.; Ashby, K.; Abadie, T.; Spina, M.; Duchamp, M.; Náfrádi, B.; Kollár, M.; Forró, L.; Horváth, E.

    2018-03-01

    We report a systematic study of the mechanical response of methylammonium lead triiodide CH3NH3PbI3 nanowires by employing bending measurements using atomic force microscope on suspended wires over photo-lithographically patterned channels. Force-deflection curves measured at room temperature give a Young's modulus between 2 and 14 GPa. This broad range of values is attributed to the variations in the microcrystalline texture of halide perovskite nanowires. The mechanical response of a highly crystalline nanowire is linear with force and has a brittle character. The braking modulus of 48 ± 20 MPa corresponds to 100 μm of radius of curvature of the nanowires, rendering them much better structures for flexible devices than spin coated films. The measured moduli decrease rapidly if the NW is exposed to water vapor.

  20. Elimination of NO/sub x/ by selective reduction with NH3

    International Nuclear Information System (INIS)

    Bruggeman, A.; Meynendonckx, L.; Gossens, W.R.A.

    1979-01-01

    In nuclear reprocessing plants the nitrogen oxides generated during the dissolution of the fuel are only partially removed in the primary off-gas treatments. Further reduction to the ppM level is necessary as a preliminary step to the cryogenic retention and separation of the noble gases. If simultaneous oxygen removal is not required, selective reduction of NO (and NO 2 ) to N 2 and H 2 O by NH 3 is a preferable method. Laboratory experiments have confrmed the feasibility of eliminating NO from air beyond the ppM level by adding NH 3 over a hydrogen mordenite catalyst. At atmospheric pressure and with air (water content 0.5% V/V) as a carrier gas selective catalytic reduction of NO to N 2 is easily achieved at temperatures up to 500 0 C. Under the same conditions dimensioning of the reactor for destruction of the excess NH 3 by the O 2 of the air is made possible. The activity of the catalyst remains rather constant even when large concentrations of I 2 are present. On the basis of the laboratory results a pilot installation has been designed and constructed which will demonstrate the process in an integrated gas purification loop at a pressure of 8 x 10 5 Pa during the next months

  1. Cytoplasmic Localization of HTLV-1 HBZ Protein: A Biomarker of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP).

    Science.gov (United States)

    Baratella, Marco; Forlani, Greta; Raval, Goutham U; Tedeschi, Alessandra; Gout, Olivier; Gessain, Antoine; Tosi, Giovanna; Accolla, Roberto S

    2017-01-01

    HTLV-1 is the causative agent of a severe form of adult T cell leukemia/Lymphoma (ATL), and of a chronic progressive neuromyelopathy designated HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). Two important HTLV-1-encoded proteins, Tax-1 and HBZ, play crucial roles in the generation and maintenance of the oncogenic process. Less information is instead available on the molecular and cellular mechanisms leading to HAM/TSP. More importantly, no single specific biomarker has been described that unambiguously define the status of HAM/TSP. Here we report for the first time the finding that HBZ, described until now as an exclusive nuclear protein both in chronically infected and in ATL cells, is instead exclusively localized in the cytoplasm of peripheral blood mononuclear cells (PBMC) from patients suffering of HAM/TSP. Interestingly, at the single cell level, HBZ and Tax-1 proteins are never found co-expressed in the same cell, suggesting the existence of mechanisms of expression uncoupling of these two important HTLV-1 viral products in HAM/TSP patients. Cells expressing cytoplasmic HBZ were almost exclusively found in the CD4+ T cell compartment that was not, at least in a representative HAM/TSP patient, expressing the CD25 marker. Less than 1 percent CD8+ T cells were fond positive for HBZ, while B cells and NK cells were found negative for HBZ in HAM/TSP patients. Our results identify the cytoplasmic localization of HBZ in HAM/TSP patient as a possible biomarker of this rather neglected tropical disease, and raise important hypotheses on the role of HBZ in the pathogenesis of the neuromyelopathy associated to HTLV-1 infection.

  2. Cytoplasmic Localization of HTLV-1 HBZ Protein: A Biomarker of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP.

    Directory of Open Access Journals (Sweden)

    Marco Baratella

    2017-01-01

    Full Text Available HTLV-1 is the causative agent of a severe form of adult T cell leukemia/Lymphoma (ATL, and of a chronic progressive neuromyelopathy designated HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP. Two important HTLV-1-encoded proteins, Tax-1 and HBZ, play crucial roles in the generation and maintenance of the oncogenic process. Less information is instead available on the molecular and cellular mechanisms leading to HAM/TSP. More importantly, no single specific biomarker has been described that unambiguously define the status of HAM/TSP. Here we report for the first time the finding that HBZ, described until now as an exclusive nuclear protein both in chronically infected and in ATL cells, is instead exclusively localized in the cytoplasm of peripheral blood mononuclear cells (PBMC from patients suffering of HAM/TSP. Interestingly, at the single cell level, HBZ and Tax-1 proteins are never found co-expressed in the same cell, suggesting the existence of mechanisms of expression uncoupling of these two important HTLV-1 viral products in HAM/TSP patients. Cells expressing cytoplasmic HBZ were almost exclusively found in the CD4+ T cell compartment that was not, at least in a representative HAM/TSP patient, expressing the CD25 marker. Less than 1 percent CD8+ T cells were fond positive for HBZ, while B cells and NK cells were found negative for HBZ in HAM/TSP patients. Our results identify the cytoplasmic localization of HBZ in HAM/TSP patient as a possible biomarker of this rather neglected tropical disease, and raise important hypotheses on the role of HBZ in the pathogenesis of the neuromyelopathy associated to HTLV-1 infection.

  3. Structural study on cubic-tetragonal transition of CH3NH3PbI3

    International Nuclear Information System (INIS)

    Kawamura, Yukihiko; Mashiyama, Hiroyuki; Hasebe, Katsuhiko

    2002-01-01

    The cubic-tetragonal phase transition of CH 3 NH 3 PbI 3 was investigated by single crystal X-ray diffractometry. The crystal structure was refined at five temperatures in the tetragonal phase. The PbI 6 octahedron rotates around the c-axis alternatively to construct the SrTiO 3 -type tetragonal structure. A methylammonium ion is partially ordered; 24 disordered states in the cubic phase are reduced to 8. With decreasing temperature, the rotation angle of the octahedron increases monotonically, which indicates it is an order parameter of the cubic-tetragonal transition. (author)

  4. The Response to P-Derived from Phosphate Rock and TSP by Crops Grown in a Simulated Crop Rotation System

    International Nuclear Information System (INIS)

    Sisworo, Elsye L; Sisworo, Widjang H; Havid-Rasjid; Syamsul-Rizal; Komarudin-Idris

    2002-01-01

    A green house experiment was carried out on a simulated crop rotation system of upland rice-soybean-mungbean to determine the effect of P-derived from different phosphate rock (PR) sources and TSP using 32 P. The data obtained reveal that all the P-sources has a significant effect on the growth of all the three crops, expressed in dry weight, % P-total and total P-uptake (mg P pot -1 ). For the P-source it was shown that % P-derived from PR/TSP and their uptake (mg P pot -1 ) was quite high, showing that the PR s applied were of good reactivity. The residue of the PR s has also still a good effect on plant growth than that of TSP. The efficiency of PR s was far below that of TSP. This apparently was due to the high rate of application, ten times the rate of TSP. (author)

  5. Transparent and flexible photodetectors based on CH3NH3PbI3 perovskite nanoparticles

    Science.gov (United States)

    Jeon, Young Pyo; Woo, Sung Jun; Kim, Tae Whan

    2018-03-01

    Transparent and flexible photodetectors (PDs) based on CH3NH3PbI3 perovskite nanoparticles (NPs) were fabricated by using co-evaporation of methyl ammonium iodide and lead iodide. X-ray diffraction patterns and high-resolution transmission electron microscopy images demonstrated the formation of perovskite NPs. The optical transmittance of the perovskite NPs/glass was above 80% over the entire range of visible wavelengths, indicative of high transparency. The PDs based on CH3NH3PbI3 perovskite NPs were sensitive to a broad range of visible light from 450 to 650 nm. The currents in the PDs under exposure to red, green, and blue light-emitting diodes were enhanced to 5, 10, and 20 times that of the PD in the dark, respectively. The rise and the decay times of the PDs were 50 and 120 μs. The current in the perovskite NP PD on a polyethylene terephthalate substrate was enhanced by approximately 69% when the NP PD was exposed to a blue LED emitting at a wavelength of 459 nm. Despite multiple bending, the transparent and flexible PDs based on methyl ammonium iodide and lead iodide NPs showed reproducibility and high stability in performance.

  6. Saharan dust contributions to PM10 and TSP levels in Southern and Eastern Spain

    Science.gov (United States)

    Rodríguez, S.; Querol, X.; Alastuey, A.; Kallos, G.; Kakaliagou, O.

    The analysis of PM10 and TSP levels recorded in rural areas from Southern and Eastern Spain (1996-1999) shows that most of the PM10 and TSP peak events are simultaneously recorded at monitoring stations up to 1000 km apart. The study of the atmospheric dynamics by back-trajectory analysis and simulations with the SKIRON Forecast System show that these high PM10 and TSP events occur when high-dust Saharan air masses are transported over the Iberian Peninsula. In the January-June period, this dust transport is mainly caused by cyclonic activity over the West or South of Portugal, whereas in the summer period this is induced by anticyclonic activity over the East or Southeast Iberian Peninsula. Most of the Saharan intrusions which exert a major influence on the particulate levels occur from May to September (63%) and in January and October. In rural areas in Northeast Spain, where the PM10 annual mean is around 18 μg PM10 m -3, the Saharan dust accounts for 4-7 annual daily exceedances of the forthcoming PM10-EU limit value (50 μg PM10 m -3 daily mean). Higher PM10 background levels are recorded in Southern Spain (30 μg PM10 m -3 as annual mean for rural areas) and very similar values are recorded in industrial and urban areas. In rural areas in Southern Spain, the Saharan dust events accounts for 10-23 annual daily exceedances of the PM10 limit value, a high number when compared with the forthcoming EU standard, which states that the limit value cannot be exceeded more than 7 days per year. The proportion of Sahara-induced exceedances with respect to the total annual exceedances is discussed for rural, urban and industrial sites in Southern Spain.

  7. The Effect of Solvents on the Performance of CH3NH3PbI3 Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Pao-Hsun Huang

    2017-04-01

    Full Text Available The properties of perovskite solar cells (PSCs fabricated using various solvents was studied. The devices had an indium tin oxide (ITO/poly(3,4-ethylenedioxythiophene: poly(styrenesulfonate (PEDOT:PSS/CH3NH3PbI3 (fabricated by using various solvents/fullerene (C60/bathocuproine (BCP/silver (Ag structure. The solvents used were dimethylformamide (DMF, γ-butyrolactone (GBL, dimethyl sulfoxide (DMSO, a mixture of DMSO and DMF (1:1 v/v, and a mixture of DMSO and GBL (DMSO: GBL, 1:1 v/v, respectively. The power conversion efficiency (PCE of the device fabricated using DMF is zero, which is attributed to the poor coverage of CH3NH3PbI3 film on the substrate. In addition, the PCE of the device made using GBL is only 1.74% due to the low solubility of PbI2 and CH3NH3I. In contrast, the PCE of the device fabricated using the solvents containing DMSO showed better performance. This is ascribed to the high solubilization properties and strong coordination of DMSO. As a result, a PCE of 9.77% was obtained using a mixed DMSO:GBL solvent due to the smooth surface, uniform film coverage on the substrate and the high crystallization of the perovskite structure. Finally, a mixed DMSO: DMF:GBL (5:2:3 v/v/v solvent that combined the advantages of each solvent was used to fabricate a device, leading to a further improvement of the PCE of the resulting PSC to 10.84%.

  8. 5 CFR 1605.22 - Claims for correction of Board or TSP record keeper errors; time limitations.

    Science.gov (United States)

    2010-01-01

    ... record keeper errors; time limitations. 1605.22 Section 1605.22 Administrative Personnel FEDERAL... § 1605.22 Claims for correction of Board or TSP record keeper errors; time limitations. (a) Filing claims... after that time, the Board or TSP record keeper may use its sound discretion in deciding whether to...

  9. Effects of NO3(-) and NH4(+) and urea on each other's uptake and incorporation

    Science.gov (United States)

    Huffaker, R. C.; Ward, M. R.

    1986-01-01

    The purpose was to determine the optimal use by wheat plants of the N sources expected from processing biological waste products, NO3(-),NO2(-)NH4(+), and urea. The approach was to determine the uptake and metabolic products of each N source (from single and multiple component solutions), inhibitory effects of each, feedback inhibition, and overall in vivo regulation of the rates of assimilation of each by wheat plants. Previously, researchers determined the interactions of NO3(-),NO2(-),NH4(+) on each other's uptake and incorporation. The assimilation and some of its effects on NO3(-) and NH4(+) assimilation which have been completed to data are discussed.

  10. Temporal variability and sources of VOCs in urban areas of the eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    C. Kaltsonoudis

    2016-11-01

    Full Text Available During the summer of 2012 volatile organic compounds (VOCs were monitored by proton transfer reaction mass spectrometry (PTR-MS in urban sites, in Athens and Patras, two of the largest cities in Greece. Also, during the winter of 2013, PTR-MS measurements were conducted in the center of the city of Athens. Positive matrix factorization (PMF was applied to the VOC measurements to gain insights about their sources. In summer most of the measured VOCs were due to biogenic and traffic emissions. Isoprene, monoterpenes, and several oxygenated VOCs (oVOCs originated mainly from vegetation either directly or as oxidation products. Isoprene average concentrations in Patras and Athens were 1 and 0.7 ppb respectively, while the monoterpene concentrations were 0.3 and 0.9 ppb respectively. Traffic was the main source of aromatic compounds during summer. For Patras and Athens the average concentrations of benzene were 0.1 and 0.2 ppb, of toluene 0.3 and 0.8 ppb, and of the xylenes 0.3 and 0.7 ppb respectively. Winter measurements in Athens revealed that biomass burning used for residential heating was a major VOC source contributing both aromatic VOCs and biogenic compounds such as monoterpenes. Several episodes related to biomass burning were identified and emission ratios (ERs and emission factors (EFs were estimated.

  11. Fast-response underwater TSP investigation of subcritical instabilities of a cylinder in crossflow

    Science.gov (United States)

    Capone, Alessandro; Klein, Christian; Di Felice, Fabio; Beifuss, Uwe; Miozzi, Massimo

    2015-10-01

    We investigate the classic cylinder in crossflow case to test the effectiveness of a fast-response underwater temperature-sensitive paint coating (TSP) in providing highly resolved spatial and time observations of the action of a flow over a bluff body surface. The flow is investigated at Reynolds number crisis state. The obtained TSP image sequences convey an accurate description of the evolution of the main features in the fluid-cylinder interaction, like the separation line position, the pattern of the large coherent structures acting on the cylinder's surface and the small-scale intermittent streamwise arrays of vortices. Ad hoc data management and features extraction techniques are proposed which allow extraction of quantitative data, such as separation line position and vortex-shedding frequency, and results are compared to the literature. Use of TSP for water applications introduces an interesting point of view about the fluid-body interactions by focusing directly on the effect of the flow on the model surface.

  12. Polymeric cobalt(ii) thiolato complexes - syntheses, structures and properties of [Co(SMes)2] and [Co(SPh)2NH3].

    Science.gov (United States)

    Eichhöfer, Andreas; Buth, Gernot

    2016-11-01

    Reactions of [Co(N(SiMe 3 ) 2 ) 2 thf] with 2.1 equiv. of MesSH (Mes = C 6 H 2 -2,4,6-(CH 3 ) 3 ) yield dark brown crystals of the one dimensional chain compound [Co(SMes) 2 ]. In contrast reactions of [Co(N(SiMe 3 ) 2 ) 2 thf] with 2.1 equiv. of PhSH result in the formation of a dark brown almost X-ray amorphous powder of 'Co(SPh) 2 '. Addition of aliquots of CH 3 OH to the latter reaction resulted in the almost quantitative formation of crystalline ammonia thiolato complexes either [Co(SPh) 2 (NH 3 ) 2 ] or [Co(SPh) 2 NH 3 ]. Single crystal XRD reveals that [Co(SPh) 2 NH 3 ] forms one-dimensional chains in the crystal via μ 2 -SPh bridges whereas [Co(SPh) 2 (NH 3 ) 2 ] consists at a first glance of isolated distorted tetrahedral units. Magnetic measurements suggest strong antiferromagnetic coupling for the two chain compounds [Co(SMes) 2 ] (J = -38.6 cm -1 ) and [Co(SPh) 2 NH 3 ] (J = -27.1 cm -1 ). Interestingly, also the temperature dependence of the susceptibility of tetrahedral [Co(SPh) 2 (NH 3 ) 2 ] shows an antiferromagnetic transition at around 6 K. UV-Vis-NIR spectra display d-d bands in the NIR region between 500 and 2250 nm. Thermal gravimetric analysis of [Co(SPh) 2 (NH 3 ) 2 ] and [Co(SPh) 2 NH 3 ] reveals two well separated cleavage processes for NH 3 and SPh 2 upon heating accompanied by the stepwise formation of 'Co(SPh) 2 ' and cobalt sulfide.

  13. DFT investigation of NH_3, PH_3, and AsH_3 adsorptions on Sc-, Ti-, V-, and Cr-doped single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Buasaeng, Prayut; Rakrai, Wandee; Wanno, Banchob; Tabtimsai, Chanukorn

    2017-01-01

    Highlights: • Transition metal-doped single wall carbon nanotubes and their adsorption with NH_3, PH_3 and AsH_3 molecules were investigated using a DFT method. • Adsorptions of NH_3, PH_3 and AsH_3 molecules on pristine single wall carbon nanotubeswere improved by transition metal doping. • Structural and electronic properties of single wall carbon nanotubes were significantly changed by transition metal doping and gas adsorptions. - Abstract: The adsorption properties of ammonia (NH_3), phosphine (PH_3), and arsine (AsH_3) on pristine and transition metal- (TM = Sc, Ti, V, and Cr) doped (5,5) armchair single-walled carbon nanotubes (SWCNTs) were theoretically investigated. The geometric and electronic properties and adsorption abilities for the most stable configuration of NH_3, PH_3, and AsH_3 adsorptions on pristine and TM-doped SWCNTs were calculated. It was found that the binding abilities of TMs to the SWCNT were in the order: Cr > V > Sc > Ti. However, the adsorption energy showed that the pristine SWCNT weakly adsorbed gas molecules and its electronic properties were also insensitive to gas molecules. By replacing a C atom with TM atoms, all doping can significantly enhance the adsorption energy of gas/SWCNT complexes and their adsorption ability was in the same order: NH_3 > PH_3 > AsH_3. A remarkable increase in adsorption energy and charge transfer of these systems was expected to induce significant changes in the electrical conductivity of the TM-doped SWCNTs. This work revealed that the sensitivity of SWCNT-based chemical gas adsorptions and sensors can be greatly improved by introducing an appropriate TM dopant. Accordingly, TM-doped SWCNTs are more suitable for gas molecule adsorptions and detections than the pristine SWCNT.

  14. Competition Between Co(NH3)63+ and Inner Sphere Mg2+ Ions in the HDV Ribozyme

    Science.gov (United States)

    Gong, Bo; Chen, Jui-Hui; Bevilacqua, Philip C.; Golden, Barbara L.; Carey, Paul R.

    2009-01-01

    Divalent cations play critical structural and functional roles in many RNAs. While the hepatitis delta virus (HDV) ribozyme can undergo self-cleavage in the presence of molar concentrations of monovalent cations, divalent cations such as Mg2+ are required for efficient catalysis under physiological conditions. Moreover, the cleavage reaction can be inhibited with Co(NH3)63+, an analog of Mg(H2O)62+. Here, the binding of Mg2+ and Co(NH3)63+ to the HDV ribozyme are studied by Raman microscopic analysis of crystals. Raman difference spectra acquired at different metal ion conditions reveal changes in the ribozyme. When Mg2+ alone is introduced to the ribozyme, inner sphere coordination of Mg(H2O)x2+ (x≤5) to non-bridging PO2− oxygen, and changes in base stretches and phosphodiester group conformation are observed. In addition, binding of Mg2+ induces deprotonation of a cytosine assigned to the general acid C75, consistent with solution studies. When Co(NH3)63+ alone is introduced, deprotonation of C75 is again observed, as are distinctive changes in base vibrational ring modes and phosphodiester backbone conformation. In contrast to Mg2+ binding, Co(NH3)63+ binding does not perturb PO2− group vibrations, consistent with its ability to make only outer sphere contacts. Surprisingly, competitive binding studies reveal that Co(NH3)63+ ions displace some inner sphere-coordinated magnesium species, including ions coordinated to PO2− groups or the N7 of a guanine, likely G1 at the active site. These observations contrast with the tenet that Co(NH3)63+ ions displace only outer sphere magnesium ions. Overall, our data support two classes of inner sphere Mg2+-PO2− binding sites: sites that Co(NH3)63+ can displace, and others it cannot. PMID:19888753

  15. NH3/O2 mixed gas plasmas alter the interaction of blood components with stainless steel.

    Science.gov (United States)

    Chen, Meng; Zamora, Paul O; Peña, Louis; Som, Prantika; Osaki, Shigemasa

    2003-12-01

    Stainless steel treated with a mixed gas plasma of NH(3) plus O(2) had chemical and biologic characteristics distinct from untreated stainless steel or stainless steel treated with NH(3) or O(2) plasmas used separately. NH(3)/O(2) plasmas deposited nitrogen as both -CN (organic) and -NO (nitrate, nitrite)--materials not found on untreated stainless steel--and the contact angle changed from 44 degrees to 23 degrees. Treatment of stainless steel (and titanium) resulted in surfaces with enhanced resistance to platelet and leukocyte attachment. A gas plasma of N(2)O/O(2) also was found to reduce platelet and leukocyte attachment, suggesting that these properties may be common to surfaces coated with oxynitrites (nitrides). Upon subcutaneous implantation, no inflammation, hemolysis, or untoward thrombosis was noted in the tissue surrounding the wafers treated with the NH(3)/O(2) plasmas, although the cellular density was considerably reduced by 2 weeks after implant. Collectively, the results suggest that NH(3)/O(2) plasmas impart a unique character to stainless steel that may be useful in the construction of medical devices. Copyright 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 994-1000, 2003

  16. THIN FILM-BASED SENSOR FOR MOTOR VEHICLE EXHAUST GAS, NH3, AND CO DETECTION

    Directory of Open Access Journals (Sweden)

    S. Sujarwata

    2016-10-01

    Full Text Available A copper phthalocyanine (CuPc thin film based gas sensor with FET structure and channel length 100 μm has been prepared by VE method and lithography technique to detect NH3, motor cycle exhaust gases and CO. CuPc material layer was deposited on SiO2 by the vacuum evaporator (VE method at room temperature and pressure of 8 x10-4 Pa. The stages of manufacturing gas sensor were Si/SiO2 substrate blenching with ethanol in an ultrasonic cleaner, source, and drain electrodes deposition on the substrate by using a vacuum evaporator, thin film deposition between the source/drain and gate deposition. The sensor response times to NH3, motorcycle exhaust gases and CO were 75 s, 135 s, and 150, respectively. The recovery times were 90 s, 150 s and 225, respectively. It is concluded that the CuPc thin film-based gas sensor with FET structure is the best sensor to detect the NH3 gas.Sensor gas berbasis film tipis copper phthalocyanine (CuPc berstruktur FET dengan panjang channel 100 μm telah dibuatdengan metode VE dan teknik lithography untuk mendeteksi NH3 gas buang kendaraan bermotor dan CO. Lapisan bahan CuPc dideposisikan pada permukaan silikon dioksida (SiO2 dengan metode vacuum evaporator (VE pada temperatur ruang dengan tekanan 8 x10-4 Pa. Tahapan pembuatan sensor gas adalah pencucian substrat Si/SiO2 dengan etanol dalam ultrasonic cleaner, deposisi elektroda source dan drain di atas substrat dengan metode vacuum evaporator, deposisi film tipis diantara source/drain dan deposisi gate. Waktu tanggap sensor terhadap NH3, gas buang kendaraan bermotor dan CO berturut-turut adalah 75 s, 135 s,dan 150 s. Waktu pemulihan berturut-turut adalah 90 s, 150 s,dan 225 s. Disimpulkan bahwa sensor gas berstruktur FET berbasis film tipis CuPc merupakan sensor paling baik untuk mendeteksi adanya gas NH3.

  17. Encapsulation of a trinuclear silver(I) cluster by two imido-nitrido metalloligands [{Ti(eta5-C5Me5)(micro-NH)}3(micro3-N)].

    Science.gov (United States)

    Martín, Avelino; Martínez-Espada, Noelia; Mena, Miguel; Yélamos, Carlos

    2007-07-28

    Treatment of the metalloligand [{Ti(eta(5)-C(5)Me(5))(micro-NH)}(3)(micro(3)-N)] with silver(i) trifluoromethanesulfonate in different molar ratios gives the ionic compounds [Ag{(micro(3)-NH)(3)Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)}(2)][O(3)SCF(3)] and [Ag{(micro(3)-NH)(3)Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)}][O(3)SCF(3)] or the triangular silver cluster [(CF(3)SO(2)O)(3)Ag(3){(micro(3)-NH)(3)Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)}(2)] in which each face is capped by a metalloligand.

  18. [Characteristics of volatile organic compounds (VOCs) emission from electronic products processing and manufacturing factory].

    Science.gov (United States)

    Cui, Ru; Ma, Yong-Liang

    2013-12-01

    Based on the EPA method T0-11 and 14/15 for measurement of toxic organics in air samples, fast VOCs detector, Summa canister and DNPH absorbent were used to determine the VOCs concentrations and the compositions in the ambient air of the workshops for different processes as well as the emission concentration in the exhaust gas. In all processes that involved VOCs release, concentrations of total VOCs in the workshops were 0.1-0.5 mg x m(-3), 1.5-2.5 mg x m(-3) and 20-200 mg x m(-3) for casting, cutting and painting respectively. Main compositions of VOCs in those workshops were alkanes, eneynes, aromatics, ketones, esters and ethers, totally over 20 different species. The main compositions in painting workshop were aromatics and ketones, among which the concentration of benzene was 0.02-0.34 mg x m(-3), toluene was 0.24-3.35 mg x m(-3), ethyl benzene was 0.04-1.33 mg x m(-3), p-xylene was 0.13-0.96 mg x m(-3), m-xylene was 0.02-1.18 mg x m(-3), acetone was 0.29-15.77 mg x m(-3), 2-butanone was 0.06-22.88 mg x m(-3), cyclohexene was 0.02-25.79 mg x m(-3), and methyl isobutyl ketone was 0-21.29 mg x m(-3). The VOCs emission from painting process was about 14 t x a(-1) for one single manufacturing line, and 840 t x a(-1) for the whole factory. According to the work flows and product processes, the solvent used during painting process was the main source of VOCs emission, and the exhaust gas was the main emission point.

  19. Nanoscale charge localization induced by random orientations of organic molecules in hybrid perovskite CH3NH3PbI3

    Science.gov (United States)

    Ma, Jie; Wang, Lin-Wang

    2015-03-01

    Perovskite-based solar cells have achieved high solar-energy conversion efficiencies and attracted wide attentions nowadays. Despite the rapid progress in solar-cell devices, many fundamental issues of the hybrid perovskites have not been fully understood. Experimentally, it is well known that in CH3NH3PbI3, the organic molecules CH3NH3 are randomly orientated at the room temperature, but the impact of the random molecular orientation has not been investigated. Using linear-scaling ab-initiomethods, we have calculated the electronic structures of the tetragonal phase of CH3NH3PbI3 with randomly orientated organic molecules in large supercells up to ~20,000 atoms. Due to the dipole moment of the organic molecule, the random orientation creates a novel system with long-range potential fluctuations unlike alloys or other conventional disordered systems. We find that the charge densities of the conduction-band minimum and the valence-band maximum are localized separately in nanoscales due to the potential fluctuations. The charge localization causes electron-hole separation and reduces carrier recombination rates, which may contribute to the long carrier lifetime observed in experiments. We have also proposed a model to explain the charge localization.

  20. O3 fast and simple treatment-enhanced p-doped in Spiro-MeOTAD for CH3NH3I vapor-assisted processed CH3NH3PbI3 perovskite solar cells

    Institute of Scientific and Technical Information of China (English)

    En-Dong Jia; Xi Lou; Chun-Lan Zhou; Wei-Chang Hao; Wen-Jing Wang

    2017-01-01

    We demonstrate a simple and fast post-deposition treatment with high process compatibility on the hole transport material (HTM) Spiro-MeOTAD in vapor-assisted solution processed methylammonium lead triiodide (CH3NH3PbI3)-based solar cells.The prepared Co-doped p-type Spiro-MeOTAD films are treated by O3 at room temperature for 5 min,10 min,and 20 min,respectively,prior to the deposition of the metal electrodes.Compared with the traditional oxidation of Spiro-MeOTAD films overnight in dry air,our fast O3 treatment of HTM at room temperature only needs just 10 min,and a relative 40.3% increment in the power conversion efficiency is observed with respect to the result of without-treated perovskite solar cells.This improvement of efficiency is mainly attributed to the obvious increase of the fill factor and short-circuit current density,despite a slight decrease in the open-circuit voltage.Ultraviolet photoelectron spectroscopy (UPS) and Hall effect measurement method are employed in our study to determine the changes of properties after O3 treatment in HTM.It is found that after the HTM is exposed to O3,its p-type doping level is enhanced.The enhancement of conductivity and Hall mobility of the film,resulting from the improvement in p-doping level of HTM,leads to better performances of perovskite solar cells.Best power conversion efficiencies (PCEs) of 13.05% and 16.39% are achieved with most properly optimized HTM via CH3NH3I vapor-assisted method and traditional single-step method respectively.

  1. Structure-controlled synthesis and electrochemical properties of NH_4V_3O_8 as cathode material for Lithium ion batteries

    International Nuclear Information System (INIS)

    Cheng, Yayi; Huang, Jianfeng; Li, Jiayin; Cao, Liyun; Xu, Zhanwei; Wu, Jianpeng; Cao, Shanshan; Hu, Hailing

    2016-01-01

    NH_4V_3O_8 flower, nanobelt, lath and sheet were synthesized using a facile microwave hydrothermal method. The formation mechanism of NH_4V_3O_8 with various structures was proposed. As an cathode in Li-ion battery, the NH_4V_3O_8 nanobelt with one-dimensional structure as well as nanosized morphology, presents excellent cycling stability and enhanced rate capability when comparing with other NH_4V_3O_8 structures. Further study finds that the NH_4V_3O_8 nanobelt could provide high Li ion diffusion, excellent structural stability and good reversibility during the charge/discharge process, indicating a strong connection between the morphology and the electrochemical performance of NH_4V_3O_8 cathode.

  2. Volatile Organic Compound (VOC) measurements in the Pearl River Delta (PRD) region, China

    Science.gov (United States)

    Liu, Ying; Shao, Min; Lu, Sihua; Chang, Chih-Chung; Wang, Jia-Lin; Chen, Gao

    2008-03-01

    We measured levels of ambient volatile organic compounds (VOCs) at seven sites in the Pearl River Delta (PRD) region of China during the Air Quality Monitoring Campaign spanning 4 October to 3 November 2004. Two of the sites, Guangzhou (GZ) and Xinken (XK), were intensive sites at which we collected multiple daily canister samples. The observations reported here provide a look at the VOC distribution, speciation, and photochemical implications in the PRD region. Alkanes constituted the largest percentage (>40%) in mixing ratios of the quantified VOCs at six sites; the exception was one major industrial site that was dominated by aromatics (about 52%). Highly elevated VOC levels occurred at GZ during two pollution episodes; however, the chemical composition of VOCs did not exhibit noticeable changes during these episodes. We calculated the OH loss rate to estimate the chemical reactivity of all VOCs. Of the anthropogenic VOCs, alkenes played a predominant role in VOC reactivity at GZ, whereas the contributions of reactive aromatics were more important at XK. Our preliminary analysis of the VOC correlations suggests that the ambient VOCs at GZ came directly from local sources (i.e., automobiles); those at XK were influenced by both local emissions and transportation of air mass from upwind areas.

  3. Volatile Organic Compound (VOC measurements in the Pearl River Delta (PRD region, China

    Directory of Open Access Journals (Sweden)

    Chih-chung Chang

    2008-03-01

    Full Text Available We measured levels of ambient volatile organic compounds (VOCs at seven sites in the Pearl River Delta (PRD region of China during the Air Quality Monitoring Campaign spanning 4 October to 3 November 2004. Two of the sites, Guangzhou (GZ and Xinken (XK, were intensive sites at which we collected multiple daily canister samples. The observations reported here provide a look at the VOC distribution, speciation, and photochemical implications in the PRD region. Alkanes constituted the largest percentage (>40% in mixing ratios of the quantified VOCs at six sites; the exception was one major industrial site that was dominated by aromatics (about 52%. Highly elevated VOC levels occurred at GZ during two pollution episodes; however, the chemical composition of VOCs did not exhibit noticeable changes during these episodes. We calculated the OH loss rate to estimate the chemical reactivity of all VOCs. Of the anthropogenic VOCs, alkenes played a predominant role in VOC reactivity at GZ, whereas the contributions of reactive aromatics were more important at XK. Our preliminary analysis of the VOC correlations suggests that the ambient VOCs at GZ came directly from local sources (i.e., automobiles; those at XK were influenced by both local emissions and transportation of air mass from upwind areas.

  4. Creation and annealing of metastable defect states in CH3NH3PbI3 at low temperatures

    Science.gov (United States)

    Lang, F.; Shargaieva, O.; Brus, V. V.; Rappich, J.; Nickel, N. H.

    2018-02-01

    Methylammonium lead iodide (CH3NH3PbI3), an organic-inorganic perovskite widely used for optoelectronic applications, is known to dissociate under illumination with light at photon energies around 2.7 eV and higher. Here, we show that photo-induced dissociation is not limited to ambient temperatures but can be observed even at 5 K. The photo-induced dissociation of N-H bonds results in the formation of metastable states. Photoluminescence (PL) measurements reveal the formation of defect states that are located 100 meV within the bandgap. This is accompanied by a quenching of the band-to-band PL by one order of magnitude. Defect generation is reversible and annealing at 30 K recovers the band-to-band PL, while the light-induced defect states disappear concurrently.

  5. Meteorite Impact-Induced Rapid NH3 Production on Early Earth: Ab Initio Molecular Dynamics Simulation

    Science.gov (United States)

    Shimamura, Kohei; Shimojo, Fuyuki; Nakano, Aiichiro; Tanaka, Shigenori

    2016-12-01

    NH3 is an essential molecule as a nitrogen source for prebiotic amino acid syntheses such as the Strecker reaction. Previous shock experiments demonstrated that meteorite impacts on ancient oceans would have provided a considerable amount of NH3 from atmospheric N2 and oceanic H2O through reduction by meteoritic iron. However, specific production mechanisms remain unclear, and impact velocities employed in the experiments were substantially lower than typical impact velocities of meteorites on the early Earth. Here, to investigate the issues from the atomistic viewpoint, we performed multi-scale shock technique-based ab initio molecular dynamics simulations. The results revealed a rapid production of NH3 within several picoseconds after the shock, indicating that shocks with greater impact velocities would provide further increase in the yield of NH3. Meanwhile, the picosecond-order production makes one expect that the important nitrogen source precursors of amino acids were obtained immediately after the impact. It was also observed that the reduction of N2 proceeded according to an associative mechanism, rather than a dissociative mechanism as in the Haber-Bosch process.

  6. Theoretical study on the gas adsorption capacity and selectivity of CPM-200-In/Mg and CPM-200-In/Mg-X (-X = -NH2, -OH, -N, -F).

    Science.gov (United States)

    Liu, Xiao-le; Chen, Guang-Hui; Wang, Xiu-Jun; Li, Peng; Song, Yi-Bing; Li, Rui-Yan

    2017-11-15

    The adsorption capacities of a heterometallic metal-organic framework (CPM-200-In/Mg) to VOCs (HCHO, C 2 H 4 , CH 4 , C 2 H 2 , C 3 H 8 , C 2 H 6 , C 2 H 3 Cl, C 2 H 2 Cl 2 , CH 2 Cl 2 and CHCl 3 ) and some inorganic gas molecules (HCN, SO 2 , NO, CO 2 , CO, H 2 S and NH 3 ), as well as its selectivity in ternary mixture systems of natural gas and post-combustion flue gas are theoretically explored at the grand canonical Monte Carlo (GCMC) and density functional theory (DFT) levels. It is shown that CPM-200-In/Mg is suitable for the adsorption of VOCs, particularly for HCHO (up to 0.39 g g -1 at 298 K and 1 bar), and the adsorption capacities of some inorganic gas molecules such as SO 2 , H 2 S and CO 2 match well with the sequence of their polarizability (SO 2 > H 2 S > CO 2 ). The large adsorption capacities of HCN and HCHO in the framework result from the strong interaction between adsorbates and metal centers, based on analyzing the radial distribution functions (RDF). Comparing C 2 H 4 and CH 4 molecules interacting with CPM-200-In/Mg by VDW interaction, we speculate that the high adsorption capacities of their chlorine derivatives in the framework could be due to the existence of halogen bonding or strong electrostatic and VDW interactions. It is found that the basic groups, including -NH 2 , -N and -OH, can effectively improve both the adsorption capacities and selectivity of CPM-200-In/Mg for harmful gases. Note that the adsorption capacity of CPM-200-In/Mg-NH 2 (site 2) (245 cm 3 g -1 ) for CO 2 exceeded that of MOF-74-Mg (228 cm 3 g -1 ) at 273 K and 1 bar and that for HCHO can reach 0.41 g g -1 , which is almost twice that of 438-MOF and nearly 45 times of that in active carbon. Moreover, for natural gas mixtures, the decarburization and desulfurization abilities of CPM-200-In/Mg-NH 2 (site 2) have exceeded those of the MOF-74 series, while for post-combustion flue gas mixtures, the desulfurization ability of CPM-200-In/Mg-NH 2 (site 2) is still

  7. Conductivity of CH{sub 3}NH{sub 3}PbI{sub 3} thin film perovskite stored in ambient atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Gebremichael, Bizuneh, E-mail: bizunehme@gmail.com [Physics Department, Addis Ababa University, Addis Ababa, P.O. Box 1176 (Ethiopia); Alemu, Getachew [Physics Department, Addis Ababa University, Addis Ababa, P.O. Box 1176 (Ethiopia); Tessema Mola, Genene [School of Chemistry & Physics, University of KwaZulu-Nat al, Pietermaritzburg Campus, Private Bag X01, Scottsville 3209 (South Africa)

    2017-06-01

    Time dependent conductivity loss in CH{sub 3}NH{sub 3}PbI{sub 3} thin film perovskite stored in ambient atmosphere were studied based on electrical and optical measurements. Recent investigations on thin film perovskite solar cell suggest that in the steady state operation of the device, the V{sub oc} is unchanged by continuous illumination of light. Rather the reduction in the power conversion efficiency is caused by significant reduction of the short circuit current (J{sub sc}). In this paper, the effect of light on the optical absorption and electrical conductivity of the CH{sub 3}NH{sub 3}PbI{sub 3} thin film which is deposited on a glass substrate is investigated. The temperature dependent conductivity measurements indicated that the dominant conduction mechanism in the film perovskite is electronic rather than ionic.

  8. Influence of hydration water on CH3NH3PbI3 perovskite films prepared through one-step procedure.

    Science.gov (United States)

    Wang, Ziyi; Yuan, Sijian; Li, Dahai; Jin, Feng; Zhang, Rongjun; Zhan, Yiqiang; Lu, Ming; Wang, Songyou; Zheng, Yuxiang; Guo, Junpeng; Fan, Zhiyong; Chen, Liangyao

    2016-10-31

    Organic-inorganic perovskites were fabricated through a one-step procedure with different levels of hydration water in precursor solutions. The optical properties of CH3NH3PbI3 films were investigated through spectroscopic ellipsometry and photoluminescence measurements. With the measured optical constants, the efficiency limit of perovskite solar cells is predicted with a detailed balance model. By comparing the optical measurement to that of planar heterojunction solar cells, we conclude that the radiative efficiency and porosity of the perovskite film significantly influence the performance of perovskite solar cells. An optimized hydration-water concentration is obtained for the 3CH3NH3I:1PbAc2•xH2O precursor solution. The results can provide guidance for further optimization of the device performance of perovskite solar cells by utilizing hydration water.

  9. Ammonia Uptake and Release in the MnX2–NH3 (X = Cl, Br Systems and Structure of the Mn(NH3nX2 (n = 6, 2 Ammines

    Directory of Open Access Journals (Sweden)

    Duncan H. Gregory

    2012-04-01

    Full Text Available Hexa-ammine complexes, Mn(NH36X2 (X = Cl, Br, have been synthesized by ammoniation of the corresponding transition metal halide and characterized by Powder X-ray diffraction (PXRD and Raman spectroscopy. The hexa-ammine complexes are isostructural (Cubic, Fm-3m, Z = 4; a = 10.2742(6 Å and 10.527(1 Å for X = Cl, Br respectively. Temperature programmed desorption (TPD demonstrated that ammonia release from Mn(NH36X2 complexes occurred in three stages corresponding to the release of 4, 1 and 1 NH3 equivalents respectively. The chloride and bromide both exhibit a deammoniation onset temperature below 323 K. The di-ammoniates from the first desorption step were isolated during TPD measurements and their crystal structures determined by Rietveld refinement against PXRD data (X = Cl: orthorhombic Cmmm, a = 8.1991(9 Å, b = 8.2498(7 Å, c = 3.8212(4 Å, Z = 2; X = Br: orthorhombic Pbam, a = 6.0109(5 Å, b = 12.022(1 Å, c = 4.0230(2 Å, Z = 2.

  10. Co-adsorption of NH3 and SO2 on quartz : Formation of a stabilized complex

    NARCIS (Netherlands)

    Grecea, M.L.; Gleeson, M.A.; van Schaik, W.; Kleyn, A.W.; Bijkerk, Frederik

    2011-01-01

    We have investigated the co-adsorption of NH3 and SO2 on the quartz(0 0 0 1) surface by TPD and RAIRS. A surface complex is formed as a result of various relative exposures of NH3 and SO2, irrespective of dosage order. However, the relative molecular composition of the complex is dependent on the

  11. Reversible flexible structural changes in multidimensional MOFs by guest molecules (I{sub 2}, NH{sub 3}) and thermal stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yang; Li, Libo; Yang, Jiangfeng; Wang, Shuang; Li, Jinping, E-mail: Jpli211@hotmail.com

    2015-03-15

    Three metal–organic frameworks (MOFs), [Cu(INA){sub 2}], [Cu(INA){sub 2}I{sub 2}] and [Cu(INA){sub 2}(H{sub 2}O){sub 2}(NH{sub 3}){sub 2}], were synthesized with 3D, 2D, and 0D structures, respectively. Reversible flexible structural changes of these MOFs were reported. Through high temperature (60–100 °C) stimulation of I{sub 2} or ambient temperature stimulation of NH{sub 3}, [Cu(INA){sub 2}] (3D) converted to [Cu(INA){sub 2}I{sub 2}] (2D) and [Cu(INA){sub 2}(H{sub 2}O){sub 2}(NH{sub 3}){sub 2}] (0D); as the temperature increased to 150 °C, the MOFs changed back to their original form. In this way, this 3D MOF has potential application in the capture of I{sub 2} and NH{sub 3} from polluted water and air. XRD, TGA, SEM, NH{sub 3}-TPD, and the measurement of gas adsorption were used to describe the changes in processes regarding the structure, morphology, and properties. - Graphical abstract: Through I{sub 2}, NH{sub 3} molecules and thermal stimulation, the three MOFs can achieve reversible flexible structural changes. Different methods were used to prove the flexible reversible changes. - Highlights: • [Cu(INA){sub 2}] can flexible transform to [Cu(INA){sub 2}I{sub 2}] and [Cu(INA){sub 2}(H{sub 2}O){sub 2}(NH{sub 3}){sub 2}] by adsorbing I{sub 2} or NH{sub 3}. • The reversible flexible transformation related to material source, temperature and concentration. • Potential applications for the capture of I{sub 2} and NH{sub 3} from polluted water or air.

  12. High-Performance CH3NH3PbI3-Inverted Planar Perovskite Solar Cells with Fill Factor Over 83% via Excess Organic/Inorganic Halide.

    Science.gov (United States)

    Jahandar, Muhammad; Khan, Nasir; Lee, Hang Ken; Lee, Sang Kyu; Shin, Won Suk; Lee, Jong-Cheol; Song, Chang Eun; Moon, Sang-Jin

    2017-10-18

    The reduction of charge carrier recombination and intrinsic defect density in organic-inorganic halide perovskite absorber materials is a prerequisite to achieving high-performance perovskite solar cells with good efficiency and stability. Here, we fabricated inverted planar perovskite solar cells by incorporation of a small amount of excess organic/inorganic halide (methylammonium iodide (CH 3 NH 3 I; MAI), formamidinium iodide (CH(NH 2 ) 2 I; FAI), and cesium iodide (CsI)) in CH 3 NH 3 PbI 3 perovskite film. Larger crystalline grains and enhanced crystallinity in CH 3 NH 3 PbI 3 perovskite films with excess organic/inorganic halide reduce the charge carrier recombination and defect density, leading to enhanced device efficiency (MAI+: 14.49 ± 0.30%, FAI+: 16.22 ± 0.38% and CsI+: 17.52 ± 0.56%) compared to the efficiency of a control MAPbI 3 device (MAI: 12.63 ± 0.64%) and device stability. Especially, the incorporation of a small amount of excess CsI in MAPbI 3 perovskite film leads to a highly reproducible fill factor of over 83%, increased open-circuit voltage (from 0.946 to 1.042 V), and short-circuit current density (from 18.43 to 20.89 mA/cm 2 ).

  13. Standardisation of Western blotting to detect HTLV-1 antibodies synthesised in the central nervous system of HAM/TSP patients

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Pereira Ribeiro

    2013-09-01

    Full Text Available Intrathecal synthesis of human T-lymphotropic virus type 1 (HTLV-1 antibodies (Abs represents conclusive evidence of a specific immune response in the central nervous system of HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP patients. Western blotting (WB for HTLV Abs in serum is a confirmatory test for HTLV-1 infection. The aim of this study was to standardise the Western blot to demonstrate the intrathecal pattern of Abs against HTLV-1 proteins in HAM/TSP patients. Paired cerebrospinal fluid (CSF and serum samples were selected from 20 patients with definite HAM/TSP, 19 HTLV-1 seronegative patients and two HTLV-1 patients without definite HAM/TSP. The presence of reactive bands of greater intensity in the CSF compared to serum (or bands in only the CSF indicated the intrathecal synthesis of anti-HTLV-1 Abs. All definite HAM/TSP patients presented with an intrathecal synthesis of anti-HTLV-1 Abs; these Abs were not detected in the control patients. The most frequent intrathecal targets of anti-HTLV-1 Abs were GD21, rgp46-I and p24 and, to a lesser extent, p19, p26, p28, p32, p36, p53 gp21 and gp46. The intrathecal immune response against env (GD21 and rgp46-I and gag (p24 proteins represents the most important humoral pattern in HAM/TSP. This response may be used as a diagnostic marker, considering the frequent association of intrathecal anti-HTLV-1 Ab synthesis with HAM/TSP and the pathogenesis of this neurological disease.

  14. Concept and development of measurement method of time sensitivity profile (TSP) in X-ray CT. Comparison of non-helical, single-slice helical, and multi-slice helical scans

    International Nuclear Information System (INIS)

    Tsujioka, Katsumi; Ida, Yoshihiro; Ohtsubo, Hironori; Takahashi, Yasukata; Niwa, Masayoshi

    2000-01-01

    We focused on the time element contained in a single CT image, and devised the concept of a time-sensitivity profile (TSP) describing how the time element is translated into an image. We calculated the data collection time range when the helical pitch is changed in non helical scans, single slice helical scans, and multi slice helical scans. We then calculated the time sensitivity profile (TSP) from the weighting applied when the data collection time range is translated into an image. TSP was also measured for each scanning method using our self-made moving phantom. TSPs obtained from the calculation and the experiments were very close. TSP showed interesting characteristics with each scanning method, especially in the case of multi slice helical scanning, in which TSP became shorter as helical pitch increased. We referred to the TSP's FWHM as the effective scanning time. When we conducted multi slice helical scanning at helical pitch 3, the effective scanning time increased to about 24% longer than that of a non helical scan. When we conducted multi slice helical scanning at helical pitch 5 or 6, the effective scanning time was about half that of a non helical scan. The time sensitivity profile (TSP) is a totally new concept that we consider an important element in discussing the time resolution of a CT scanner. The results of this review will provide significant data in determining the scanning parameters when scanning a moving object. (author)

  15. VOCs in Arid soils: Technology summary

    International Nuclear Information System (INIS)

    1994-02-01

    The Volatile Organic Compounds In Arid Soils Integrated Demonstration (VOC-Arid ID) focuses on technologies to clean up volatile organic compounds and associated contaminants in soil and groundwater at arid sites. The initial host site is the 200 West Area at DOE's Hanford site in southeastern Washington state. The primary VOC contaminant is carbon tetrachloride, in association with heavy metals and radionuclides. An estimated 580--920 metric tons of carbon tetrachloride were disposed of between 1955 and 1973, resulting in extensive soil and groundwater contamination. The VOC-Arid ID schedule has been divided into three phases of implementation. The phased approach provides for: rapid transfer of technologies to the Environmental Restoration (EM-40) programs once demonstrated; logical progression in the complexity of demonstrations based on improved understanding of the VOC problem; and leveraging of the host site EM-40 activities to reduce the overall cost of the demonstrations. During FY92 and FY93, the primary technology demonstrations within the ID were leveraged with an ongoing expedited response action at the Hanford 200 West Area, which is directed at vapor extraction of VOCs from the vadose (unsaturated) zone. Demonstration efforts are underway in the areas of subsurface characterization including: drilling and access improvements, off-gas and borehole monitoring of vadose zone VOC concentrations to aid in soil vapor extraction performance evaluation, and treatment of VOC-contaminated off-gas. These current demonstration efforts constitute Phase 1 of the ID and, because of the ongoing vadose zone ERA, can result in immediate transfer of successful technologies to EM-40

  16. Preparation of planar CH{sub 3}NH{sub 3}PbI{sub 3} thin films with controlled size using 1-ethyl-2-pyrrolidone as solvent

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Qiuyan; Chu, Yixia [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Zheng, Xuerong [Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Liu, Zhenya; Liang, Liming [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Qi, Jiakun [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Xin [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Liu, Gang [School of Chemical Engineering, Hebei University of Technology, Tianjin 300132 (China); Liu, Hui, E-mail: liuhuihebut@163.com [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Chen, Hongjian [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Liu, Caichi, E-mail: ccliu@hebut.edu.cn [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China)

    2016-06-25

    Recently, planar perovskite solar cells based on CH{sub 3}NH{sub 3}PbI{sub 3} have attracted many researcher's interest due to their unique advantages such as simple cell architecture, easy fabrication and potential multijunction construction comparing to the initial mesoporous structure. However, the preparation of planar perovskite films with high quality is still in challenge. In this paper, we developed a vapor-assisted solution process using a novel and green solvent of 1-Ethyl-2-pyrrolidone (NEP) instead of the traditional N, N-dimethylformamide (DMF) to construct a high-quality perovskite CH{sub 3}NH{sub 3}PbI{sub 3} thin film with pure phase, high compactness, small surface roughness and controlled size. The phase evolution and growth mechanism of the perovskite films are also discussed. Utilizing the NEP of low volatility and moderate boiling point as solvent, we dried the PbI{sub 2}-NEP precursor films at different temperature under vacuum and then obtained PbI{sub 2} thin films with different crystalline degree from amorphous to highly crystalline. The perovskite films with crystal size ranged from hundreds of nanometers to several micrometers can be prepared by reacting the PbI{sub 2} films of different crystalline degree with CH{sub 3}NH{sub 3}I vapor. Moreover, planar-structured solar cells combining the perovskite film with TiO{sub 2} and spiro-OMeTAD as the electron and holes transporting layer achieves a power conversion efficiency of 10.2%. - Highlights: • A novel and green solvent of 1-Ethyl-2-pyrrolidone (NEP) was used to construct high-quality perovskite CH{sub 3}NH{sub 3}PbI{sub 3} thin film. • The CH{sub 3}NH{sub 3}PbI{sub 3} grain with different sizes ranged from hundreds of nanometers to several micrometers can be obtained. • Planar-structured perovskite CH{sub 3}NH{sub 3}PbI{sub 3} solar cells using NEP as solvent achieves a power conversion efficiency of 10.2%.

  17. Characteristics of NH4+ and NO3− fluxes in tea (Camellia sinensis) roots measured by scanning ion-selective electrode technique

    Science.gov (United States)

    Ruan, Li; Wei, Kang; Wang, Liyuan; Cheng, Hao; Zhang, Fen; Wu, Liyun; Bai, Peixian; Zhang, Chengcai

    2016-01-01

    As a vital beverage crop, tea has been extensively planted in tropical and subtropical regions. Nitrogen (N) levels and forms are closely related to tea quality. Based on different N levels and forms, we studied changes in NO3− and NH4+ fluxes in tea roots utilizing scanning ion-selective electrode technique. Our results showed that under both single and mixed N forms, influx rates of NO3− were much lower than those of NH4+, suggesting a preference for NH4+ in tea. With the increase in N concentration, the influx rate of NO3− increased more than that of NH4+. The NH4+ influx rates in a solution without NO3− were much higher than those in a solution with NO3−, while the NO3− influx rates in a solution without NH4+ were much lower than those in a solution with NH4+. We concluded that (1) tea roots showed a preference for NH4+, (2) presence of NO3− had a negative effect on NH4+ influx, and (3) NH4+ had a positive effect on NO3− influx. Our findings not only may help advance hydroponic tea experiments but also may be used to develop efficient fertilization protocols for soil-grown tea in the future. PMID:27918495

  18. Efficiency enhancement of perovskite solar cells using structural and morphological improvement of CH3NH3PbI3 absorber layers

    Science.gov (United States)

    Alidaei, Maryam; Izadifard, Morteza; Ghazi, Mohammad E.; Ahmadi, Vahid

    2018-01-01

    Perovskite solar cells have been heavily investigated due to their unique properties such as high power conversion efficiency (PCE), low-cost fabrication by solution processes, high diffusion length, large absorption coefficient, and direct and tunable band gap. PCE of perovskite devices is strongly dependent on the absorber layer properties such as morphology, crystallinity, and compactness, which are required to be optimized. In this work, the CH3NH3PbI3 (170-480 nm) absorber layers with various methylammonium iodine (MAI) concentrations (7, 10, 20 and 40 mg ml-1) and perovskite solar cells with the fluorine-doped tin oxide (400 nm)/C-TiO2 (30 nm)/Meso-TiO2 (400 nm)/CH3NH3PbI3 (170-480 nm)/P3HT (30 nm)/Au (100 nm) structure were fabricated. A two-step solution process was used for deposition of the CH3NH3PbI3 absorber layers. The morphology, crystal structure, and optical properties of the perovskite layer grown on glass and also the photovoltaic properties of the fabricated solar cells were studied. The results obtained showed that by controlling the deposition conditions, due to the reduction in charge recombination, PCE enhancement of the perovskite solar cell (up to 11.6%) was accessible.

  19. Solvothermal indium fluoride chemistry: Syntheses and crystal structures of K5In3F14, β-(NH4)3InF6 and [NH4]3[C6H21N4]2[In4F21

    International Nuclear Information System (INIS)

    Jayasundera, Anil C.A.; Goff, Richard J.; Li Yang; Finch, Adrian A.; Lightfoot, Philip

    2010-01-01

    The solvothermal syntheses and crystal structures of three indium fluorides are presented. K 5 In 3 F 14 (1) and β-(NH 4 ) 3 InF 6 (2) are variants on known inorganic structure types chiolite and cryolite, respectively, with the latter exhibiting a complex and apparently novel structural distortion. [NH 4 ] 3 [C 6 H 21 N 4 ] 2 [In 4 F 21 ] (3) represents a new hybrid composition displaying a unique trimeric metal fluoride building unit. - Graphical abstract: Solvothermal synthesis has been used to prepare three indium fluorides, including a novel hybrid material containing a unique [In 3 F 15 ] trimer templated by tren.

  20. Synthesis and structure of a 1,6-hexyldiamine heptaborate, [H3N(CH2)6NH3][B7O10(OH)3

    International Nuclear Information System (INIS)

    Yang Sihai; Li Guobao; Tian Shujian; Liao Fuhui; Xiong Ming; Lin Jianhua

    2007-01-01

    A new 1,6-hexyldiamine heptaborate, [H 3 N(CH 2 ) 6 NH 3 ][B 7 O 10 (OH) 3 ] (1), has been solvothermally synthesized and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis, and thermogravimetric analysis. Compound 1 crystallizes in monoclinic system, space group P2 1 /n with a=8.042(2) A, b=20.004(4) A, c=10.103(2) A, and β=90.42(3) deg. The anionic [B 7 O 10 (OH) 3 ] n 2n- layers are interlinked via hydrogen bonding to form a 3D supramolecular network containing large channels, in which the templated [H 3 N(CH 2 ) 6 NH 3 ] 2+ cations are located. - Graphical abstract: A layered 1,6-hexyldiamine heptaborate, [H 3 N(CH 2 ) 6 NH 3 ][B 7 O 10 (OH) 3 ], was solvothermally synthesized at 150 deg. C. It is a layer borate and crystallized in monoclinic space group P2 1 /n with a=8.042(2) A, b=20.004(4) A, c=10.103(2) A, β=90.42(3) deg

  1. Suns-VOC characteristics of high performance kesterite solar cells

    Science.gov (United States)

    Gunawan, Oki; Gokmen, Tayfun; Mitzi, David B.

    2014-08-01

    Low open circuit voltage (VOC) has been recognized as the number one problem in the current generation of Cu2ZnSn(Se,S)4 (CZTSSe) solar cells. We report high light intensity and low temperature Suns-VOC measurement in high performance CZTSSe devices. The Suns-VOC curves exhibit bending at high light intensity, which points to several prospective VOC limiting mechanisms that could impact the VOC, even at 1 sun for lower performing samples. These VOC limiting mechanisms include low bulk conductivity (because of low hole density or low mobility), bulk or interface defects, including tail states, and a non-ohmic back contact for low carrier density CZTSSe. The non-ohmic back contact problem can be detected by Suns-VOC measurements with different monochromatic illuminations. These limiting factors may also contribute to an artificially lower JSC-VOC diode ideality factor.

  2. Preliminary measurements of aromatic VOCs in public transportation modes in Guangzhou, China.

    Science.gov (United States)

    Chan, L Y; Lau, W L; Wang, X M; Tang, J H

    2003-07-01

    This study examined the exposure level of aromatic volatile organic compounds (VOCs) in public transportation modes in Guangzhou, China. A total of 40 VOC samples were conducted in four popular public commuting modes (subway, taxis, non-air-conditioned buses and air-conditioned buses) while traversing in urban areas of Guangzhou. Traffic-related VOCs (benzene, toluene, ethylbenzene, m/p-xylene and o-xylene) were collected on adsorbent tubes and analyzed by thermal desorption (TD) and gas chromatography/mass-selective detector (GC/MSD) technique. The results indicate that commuter exposure to VOCs is greatly influenced by the choice of public transport. For the benzene measured, the mean exposure level in taxis (33.6 microg/m(3)) was the highest and was followed by air-conditioned buses (13.5 microg/m(3)) and non-air-conditioned buses (11.3 microg/m(3)). The exposure level in the subway (7.6 microg/m(3)) is clearly lower than that in roadway transports. The inter-microenvironment variations of other target compounds were similar to that of benzene. The target VOCs were well correlated to each other in all the measured transports. The concentration profile of the measured transport was also investigated and was found to be similar to each other. Based on the experiment results, the average B/T/E/X found in this study was about (1.0/4.3/0.7/1.4). In this study, the VOC levels measured in evening peak hours were only slightly higher than those in afternoon non-peak hours. This is due to the insignificant change of traffic volume on the measured routes between these two set times. The out-dated vehicle emission controls and slow-moving traffic conditions may be the major reasons leading elevated in-vehicle exposure level in some public commuting journeys.

  3. Chlorine Incorporation in the CH3NH3PbI3 Perovskite: Small Concentration, Big Effect.

    Science.gov (United States)

    Quarti, Claudio; Mosconi, Edoardo; Umari, Paolo; De Angelis, Filippo

    2017-01-03

    The role of chlorine doping in CH 3 NH 3 PbI 3 represents an important open issue in the use of hybrid perovskites for photovoltaic applications. In particular, even if a positive role of chlorine doping on perovskite film formation and on material morphology has been demonstrated, an inherent positive effect on the electronic and photovoltaic properties cannot be excluded. Here we carried out periodic density functional theory and Car-Parrinello molecular dynamics simulations, going down to ∼1% doping, to investigate the effect of chlorine on CH 3 NH 3 PbI 3 . We found that such a small doping has important effects on the dynamics of the crystalline structure, both with respect to the inorganic framework and with respect to the cation libration motion. Together, we observe a dynamic spatial localization of the valence and conduction states in separated spatial material regions, which takes place in the 10 -1 ps time scale and which could be the key to ease of exciton dissociation and, likely, to small charge recombination in hybrid perovskites. Moreover, such localization is enhanced by chlorine doping, demonstrating an inherent positive role of chlorine doping on the electronic properties of this class of materials.

  4. Optical absorption enhancement in NH2CH=NH2PbI3 lead halide perovskite solar cells with nanotextures

    Science.gov (United States)

    Xie, Ziang; Sun, Shuren; Xie, Xixi; Hou, Ruixiang; Xu, Wanjin; Li, Yanping; Qin, G. G.

    2018-01-01

    This article reports, for the first time to our knowledge, that the power conversion efficiencies (PCEs) of planar NH2CH=NH2PbI3 (FAPbI3) lead halide perovskite solar cells (SCs) can be largely improved by fabricating nanotextures on the SC surface. Four kinds of nanotextures are investigated and compared with each other: column hollow (CLH) nanoarrays, cone hollow (CNH) nanoarrays, square prism hollow (SPH) nanoarrays, and pyramid hollow (PYH) nanoarrays. Compared with the PCEs of the planar SCs with the same layer depth d, it is found that when d is in the range of 125-500 nm and when the array period, as well as the filling fraction of the nanotexture, are optimized, the ultimate efficiency increased 29%-50% for the CLH and SPH textured FAPbI3 SCs relative to the planar ones, and 20%-41% for the CNH and PYH textured FAPbI3 SCs relative to the planar ones. When d < 250 nm, the optimized ultimate efficiencies of the CLH and SPH textured FAPbI3 SCs with optimized nanotextures are higher than those of the CNH and PYH ones, and vice versa. The reasons why fabricating nanotextures on SC surfaces can largely improve the PCE of the FAPbI3 SCs are discussed.

  5. Ambient volatile organic compounds (VOCs) in Calgary, Alberta: Sources and screening health risk assessment.

    Science.gov (United States)

    Bari, Md Aynul; Kindzierski, Warren B

    2018-08-01

    Exposure to ambient volatile organic compound (VOCs) in urban areas is of interest because of their potential chronic and acute adverse effects to public health. Limited information is available about VOC sources in urban areas in Canada. An investigation of ambient VOCs levels, their potential sources and associated risks to public health was undertaken for the urban core of Alberta's largest city (downtown Calgary) for the period 2010-2015. Twenty-four hour arithmetic and geometric mean concentrations of total VOCs were 42μg/m 3 and 39μg/m 3 , respectively and ranged from 16 to 160μg/m 3 , with winter levels about two-fold higher than summer. Alkanes (58%) were the most dominant compounds followed by halogenated VOCs (22%) and aromatics (11%). Mean and maximum 24h ambient concentrations of selected VOCs of public health concern were below chronic and acute health risk screening criteria of the United States regulatory agencies and a cancer screening benchmark used in Alberta equivalent to 1 in 100,000 lifetime risk. The Positive matrix factorization (PMF) model revealed nine VOC sources at downtown Calgary, where oil/natural gas extraction/combustion (26%), fuel combustion (20%), traffic sources including gasoline exhaust, diesel exhaust, mixed fugitive emissions (10-15%), and industrial coatings/solvents (12%) were predominant. Other sources included dry cleaning (3.3%), biogenic (3.5%) and a background source (18%). Source-specific health risk values were also estimated. Estimated cancer risks for all sources were below the Alberta cancer screening benchmark, and estimated non-cancer risks for all sources were well below a safe level. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. VizieR Online Data Catalog: MSX high-contrast IRDCs with NH3 (Chira+,

    Science.gov (United States)

    Chira, R.-A.; Beuther, H.; Linz, H.; Walmsley, C. M.; Menten, K. M.; Bonfman, L.

    2013-02-01

    Based on MSX data, a catalogue of more than 10,000 candidate IRDCs was compiled. From this catalogue we selected a complete sample of northern hemisphere high-contrast IRDCs with Galactic longitudes >=19.27° (and nine exceptions with Galactic longitudes <19°). The sample was observed in ammonia (1,1) and (2,2) inversion transitions with the Effelsberg 100-m telescope. NH3 parameters are derived for 109 sample sources. For each source galactic coordinates, brightness temperatures, line width FWHMs and optical depths of (1,1) and (2,2) inversion lines and LSR velocity of (1,1) inversion line are given. Furthermore, we derived the rotation and kinetic temperatures, ammonia column densities, kinematic distances and virial masses using the NH3 data. In addition, notes about whether the sources being associated with Spitzer sources or not are given. Using ATLASGAL data, the 870 micron flux densities gas masses, virial parameters, H2 column densities and NH3 abundances are given. In addition, we listed the sample sources where no ammonia which did not fulfil our selection criteria. (4 data files).

  7. NO3-/NH4+ ratios affect nutritional homeostasis and production of Tanzania guinea grass under Cu toxicity.

    Science.gov (United States)

    de Souza Junior, João Cardoso; Nogueirol, Roberta Corrêa; Monteiro, Francisco Antonio

    2018-05-01

    Nitrogen (N) can alleviate metal toxicity. However, as of yet, there have been no studies showing the efficacy of NO 3 - /NH 4 + in mitigating Cu toxicity. The objective of this study was to evaluate the Cu toxicity on the nutritional and productive attributes of Panicum maximum cv. Tanzania as well as the role of NO 3 - and NH 4 + ratios in nutritional homeostasis. The experiment was conducted using 3 × 4 factorial treatments arranged in a randomized complete block design with three replicates. The treatments were three NO 3 - /NH 4 + ratios (100/0, 70/30, and 50/50) and four Cu rates (0.3, 250, 500, and 1000 μmol L -1 ) in nutrient solution. Copper concentrations in the diagnostic leaves (DL) were highest in plants grown under 70/30 NO 3 - /NH 4 + ratios and a Cu rate of 1000 μmol L -1 . In this combination, it was observed that DL had higher concentrations of NH 4 + , greater glutamine synthetase activity, lower chlorophyll concentration (SPAD value), and lower shoot dry mass, suggesting high disorders of nutritional homeostasis. Plants receiving N in the form of NO 3 - and 1000 Cu μmol L -1 showed that DL had lower concentrations of Cu, higher concentration of chlorophyll, higher NO 3 - concentration, higher nitrate reductase activity, and higher NO 3 - accumulation in the roots, suggesting a reduction in disorders of nutritional homeostasis. The disorders on mineral uptake, N assimilation, and biomass production caused by Cu toxicity are shown to be affected by NO 3 - /NH 4 + ratios, and N supply via NO 3 - allowed for better homeostasis of the forage grass.

  8. Modeling unsteady-state VOC transport in simulated waste drums

    International Nuclear Information System (INIS)

    Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Hotz, N.J.; Connolly, M.J.

    1994-01-01

    This report is a revision of an EG ampersand G Idaho informal report originally titled Modeling VOC Transport in Simulated Waste Drums. A volatile organic compound (VOC) transport model has been developed to describe unsteady-state VOC permeation and diffusion within a waste drum. Model equations account for three primary mechanisms for VOC transport from a void volume within the drum. These mechanisms are VOC permeation across a polymer boundary, VOC diffusion across an opening in a volume boundary, and VOC solubilization in a polymer boundary. A series of lab-scale experiments was performed in which the VOC concentration was measured in simulated waste drums under different conditions. A lab-scale simulated waste drum consisted of a sized-down 55-gal metal drum containing a modified rigid polyethylene drum liner. Four polyethylene bags were sealed inside a large polyethylene bag, supported by a wire cage, and placed inside the drum liner. The small bags were filled with VOC-air gas mixture and the VOC concentration was measured throughout the drum over a period of time. Test variables included the type of VOC-air gas mixtures introduced into the small bags, the small bag closure type, and the presence or absence of a variable external heat source. Model results were calculated for those trials where the permeability had been measured

  9. Structure, phonon properties, and order-disorder transition in the metal formate framework of [NH4][Mg(HCOO)3].

    Science.gov (United States)

    Mączka, Mirosław; Pietraszko, Adam; Macalik, Bogusław; Hermanowicz, Krzysztof

    2014-01-21

    We report the synthesis, crystal structure, thermal, dielectric, IR, and Raman studies of [NH4][Mg(HCOO)3] formate. Single-crystal X-ray diffraction shows that it crystallizes in the hexagonal space group P6322, with orientationally disordered NH4(+) ions located in the cages of the network. Upon cooling, [NH4][Mg(HCOO)3] undergoes a phase transition at around 255 K to the ferroelectric P63 structure. Raman and IR spectra show a strong increase in intensity of the N-H stretching bands as well as narrowing of the bands related to the NH4(+) ions upon cooling. These changes indicate that the phase transition is due to orientational ordering of the NH4(+) ions. Analysis of the Raman data show, however, that the rotational and translational motions of NH4(+) do not freeze completely at the phase transition but exhibit further slowing down below 255 K, and the motional freezing becomes nearly complete below 140 K.

  10. NQR and X-ray crystal structure studies of cadmium halide complexes: [C(NH2)3]CdI3 and [4-ClC6H5NH3]3CdBr5

    International Nuclear Information System (INIS)

    Gesing, Thorsten M.; Lork, Enno; Terao, Hiromitsu; Ishihara, Hideta

    2016-01-01

    The crystal structures of [C(NH 2 ) 3 ]CdI 3 (1) and [4-ClC 6 H 5 NH 3 ] 3 CdBr 5 (2) have been determined at 100 K: monoclinic, Cc, a = 828.75(3) pm, b = 1615.31(5) pm, c = 810.64(3) pm, and β = 106.5820(10) for 1; monoclinic, P2 1 /c, a = 1486.93(5) pm, b = 794.31(3) pm, c = 2290.59(7) pm, and β = 99.6830(10) for 2. The structure of 1 has an infinite chain of anions consisting of [CdI 4 ] tetrahedra sharing two corners. The structure of 2 has an infinite chain of anions consisting of [CdBr 6 ] octahedra sharing two corners in cis positions. In both structures, isolated cations are connected to the anion chains through weak hydrogen bonds Cd-X..H to result in three-dimensional network structures. In accordance with the crystal structures, three 127 I (m = ±1/2 <-> m = ±3/2), five 81 Br, and three 35 Cl nuclear quadrupole resonance (NQR) lines were observed for 1 and 2. The NQR spectra reflect the anion chain structures and their weak hydrogen bonds. The MO calculations of the models [Cd 5 I 16 ] 6- for 1 and [Cd 3 Br 16 ] 10- for 2 estimate only about half the values for the NQR frequencies but give accurate electric field gradient directions.

  11. Surface modification of coconut shell based activated carbon for the improvement of hydrophobic VOC removal.

    Science.gov (United States)

    Li, Lin; Liu, Suqin; Liu, Junxin

    2011-08-30

    In this study, coconut shell based carbons were chemically treated by ammonia, sodium hydroxide, nitric acid, sulphuric acid, and phosphoric acid to determine suitable modification for improving adsorption ability of hydrophobic volatile organic compounds (VOCs) on granular activated carbons (GAC). The saturated adsorption capacities of o-xylene, a hydrophobic volatile organic compound, were measured and adsorption effects of the original and modified activated carbons were compared. Results showed that GAC modified by alkalis had better o-xylene adsorption capacity. Uptake amount was enhanced by 26.5% and reduced by 21.6% after modification by NH(3)H(2)O and H(2)SO(4), respectively. Compared with the original, GAC modified by acid had less adsorption capacity. Both SEM/EDAX and BET were used to identify the structural characteristics of the tested GAC, while IR spectroscopy and Boehm's titration were applied to analysis the surface functional groups. Relationships between physicochemical characteristics of GAC and their adsorption performances demonstrated that o-xylene adsorption capacity was related to surface area, pore volume, and functional groups of the GAC surface. Removing surface oxygen groups, which constitute the source of surface acidity, and reducing hydrophilic carbon surface favors adsorption capacity of hydrophobic VOCs on carbons. The performances of modified GACs were also investigated in the purification of gases containing complex components (o-xylene and steam) in the stream. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. [The rotationally stable screw-anchor with trochanteric stabilizing plate (RoSA/TSP) : First results in unstable trochanteric femur fractures].

    Science.gov (United States)

    Maier, K-J; Bücking, B; Horst, K; Andruszkow, H; Hildebrand, F; Knobe, M

    2017-12-01

    In unstable trochanteric fractures, the extramedullary rotationally stable screw-anchor (RoSA) combines the benefits of the load and rotational stability of the blade with the advantages of the screw (pull-out resistance, compression capability) in a single load carrier, and was designed to prevent femoral neck shortening by using an additional locked trochanteric stabilizing plate (TSP). The aim of the current prospective cohort study was the clinical evaluation of the RoSA/TSP system regarding the mechanical re-operation rate and the amount of postoperative femoral neck shortening. From September 2011 to January 2014 80 patients with unstable trochanteric fractures underwent internal extramedullary fixation with the RoSA/TSP (Königsee Implantate GmbH, Allendorf, Germany). Due to fracture stability and after induction of compression, additional long locked antitelescoping screws (AT, n = 1-4) were placed reaching the femoral head. Radiological (femoral neck shortening) and clinical re-examination of patients (n = 61) was performed 6-10 weeks and 6-10 months later. In the 61 re-examined patients (76 %) femoral neck shortening was very low with 2 mm 6-10 months after operation. Re-operations occurred in 8 % (n = 6) and in 4 % (n = 3) as prophylactic surgical intervention. Whereas one-third (4 %) of re-operations occurred due to iatrogenic surgical problems from the first operation two-thirds of patients (8 %) had a re-operation due to delay of bone union (3× nonunion, 3 planned removals of AT-screws to improve healing). The in-hospital mortality was 3 % (n = 2). The fixation of unstable trochanteric femur fractures using the RoSA/TSP in a first clinical setting led to a great primary stability, with significant advantages with regard to limited femoral neck shortening. However, the rigidity of the construct with its consequences regarding bone healing can be challenging for the surgeon. Nevertheless, in some cases of revision it could be beneficial

  13. [CH(3)(CH(2))(11)NH(3)]SnI(3): a hybrid semiconductor with MoO(3)-type tin(II) iodide layers.

    Science.gov (United States)

    Xu, Zhengtao; Mitzi, David B

    2003-10-20

    The organic-inorganic hybrid [CH(3)(CH(2))(11)NH(3)]SnI(3) presents a lamellar structure with a Sn-I framework isotypic to that of MoO(3). The SnI(3)(-) layer consists of edge and corner-sharing SnI(6) octahedra in which one of the six Sn-I bonds is distinctly elongated (e.g., 3.62 A), indicating lone-pair stereoactivity for the Sn(II) atom. The overall electronic character remains comparable with that of the well-studied SnI(4)(2)(-)-based perovskite semiconductors, such as [CH(3)(CH(2))(11)NH(3)](2)SnI(4), with a red-shifted and broadened exciton peak associated with the band gap, apparently due to the increased dimensionality of the Sn-I framework. The title compound offers, aside from the hybrid perovskites, a new type of solution-processable Sn-I network for potential applications in semiconductive devices.

  14. EDF steam generators fleet: In-operation monitoring of TSP blockage and tube fouling

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, P.; Gay, N.; Crinon, R. [Electricite De France (France)

    2012-07-01

    EDF operates 58 Pressurized Water Reactors in France. In the mid 2000‟s some of them have been affected by Steam Generators (SG) Tube Support Plates (TSP) blockage and U-tubes external surface fouling with iron oxides deposits due to corrosion of secondary-side components. These issues have been tackled by a global maintenance strategy of chemical cleanings and a method for in-operation monitoring of fouling and TSP blockage has been developed and is implemented since mid 2009. This monitoring is aimed at giving information for SG maintenance planning as regards non destructive examinations and chemical cleaning. This paper will first remind of the physical reasons of fouling and TSP blockage and identify the resulting stakes regarding safety and availability along with the action levers available to control both phenomena. Then details will be given on how in-operation monitoring of fouling and TSP blockage is carried out, using measurements of Wide Range water Level (WRL) and SG steam pressure during thermally stabilized periods. Information will also be given on how those data are analyzed and shared as well at a local as at a corporate level to participate in the planning of SG inspection and maintenance operations. Finally, possible refinements will be discussed, notably regarding the issue of WRL measurements reliability and the possibility to use the analysis of SG dynamic behavior during power transients to assess the TSP blockage ratio. In terms of „issues requiring discussion‟, the following are operational issues currently being investigated by EDF: 1. SG pressure can have quite large variations during one operating cycle (notably after a plant trip) and from one cycle to the other and generally pressure tends to decrease on a long-term basis. How can such variations be explained? What are the solutions to moderate/stop the pressure loss? 2. On some of the SG-models operated by EDF, hard curative Chemical Cleaning of the U-tubes didn't bring

  15. INTERACTIONS OF ELEVATED CO2, NH3 AND O-3 ON MYCORRHIZAL INFECTION, GAS-EXCHANGE AND N-METABOLISM IN SAPLINGS OF SCOTS PINE

    NARCIS (Netherlands)

    PEREZSOBA, M; DUECK, TA; PUPPI, G; KUIPER, PJC

    Four-year-old saplings of Scots pine (Pinus sylvestris L.) were exposed for 11 weeks in controlled-environment chambers to charcoal-filtered air, or to charcoal-filtered air supplemented with NH3 (40 mu g m(-3)), O-3 (110 mu g m(-3) during day/ 40 mu g m(-3) during night) or NH3 + O-3. All

  16. NH3 (10-00) in the pre-stellar core L1544

    DEFF Research Database (Denmark)

    Caselli, P.; Bizzocchi, L.; Keto, E.

    2017-01-01

    GHz and study the abundance profile of ammonia across the pre-stellar core L1544 to test current theories of its physical and chemical structure. Recently calculated collisional coefficients have been included in our non-LTE radiative transfer code to reproduce Herschel observations. A gas......Pre-stellar cores represent the initial conditions in the process of star and planet formation, therefore it is important to study their physical and chemical structure. Because of their volatility, nitrogen-bearing molecules are key to study the dense and cold gas present in pre-stellar cores....... The NH3 rotational transition detected with Herschel-HIFI provides a unique combination of sensitivity and spectral resolution to further investigate physical and chemical processes in pre-stellar cores. Here we present the velocity-resolved Herschel-HIFI observations of the ortho-NH3(10-00) line at 572...

  17. Brightly Luminescent and Color-Tunable Colloidal CH3NH3PbX3 (X = Br, I, Cl) Quantum Dots: Potential Alternatives for Display Technology.

    Science.gov (United States)

    Zhang, Feng; Zhong, Haizheng; Chen, Cheng; Wu, Xian-gang; Hu, Xiangmin; Huang, Hailong; Han, Junbo; Zou, Bingsuo; Dong, Yuping

    2015-04-28

    Organometal halide perovskites are inexpensive materials with desirable characteristics of color-tunable and narrow-band emissions for lighting and display technology, but they suffer from low photoluminescence quantum yields at low excitation fluencies. Here we developed a ligand-assisted reprecipitation strategy to fabricate brightly luminescent and color-tunable colloidal CH3NH3PbX3 (X = Br, I, Cl) quantum dots with absolute quantum yield up to 70% at room temperature and low excitation fluencies. To illustrate the photoluminescence enhancements in these quantum dots, we conducted comprehensive composition and surface characterizations and determined the time- and temperature-dependent photoluminescence spectra. Comparisons between small-sized CH3NH3PbBr3 quantum dots (average diameter 3.3 nm) and corresponding micrometer-sized bulk particles (2-8 μm) suggest that the intense increased photoluminescence quantum yield originates from the increase of exciton binding energy due to size reduction as well as proper chemical passivations of the Br-rich surface. We further demonstrated wide-color gamut white-light-emitting diodes using green emissive CH3NH3PbBr3 quantum dots and red emissive K2SiF6:Mn(4+) as color converters, providing enhanced color quality for display technology. Moreover, colloidal CH3NH3PbX3 quantum dots are expected to exhibit interesting nanoscale excitonic properties and also have other potential applications in lasers, electroluminescence devices, and optical sensors.

  18. Fabrication and characterization of perovskite-based CH{sub 3}NH{sub 3}Pb{sub 1-x}Ge{sub x}I{sub 3}, CH{sub 3}NH{sub 3}Pb{sub 1-x}Tl{sub x}I{sub 3} and CH{sub 3}NH{sub 3}Pb{sub 1-x}In{sub x}I{sub 3} photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Ohishi, Yuya; Oku, Takeo, E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi [Department of Materials Science, The University of Shiga Prefecture 2500 Hassaka, Hikone, Shiga 522-8533 (Japan)

    2016-02-01

    Perovskite-type CH{sub 3}NH{sub 3}PbI{sub 3}-based photovoltaic devices were fabricated and characterized. Doping effects of thallium (Tl), indium (In), or germanium (Ge) element on the photovoltaic properties and surface structures of the perovskite phase were investigated. The open circuit voltage increased by Ge addition, and fill factors were improved by adding a small amount of Ge, Tl or In. In addition, the wavelength range of incident photon conversion efficiencies was expanded by the Tl addition.

  19. Morphology-photovoltaic property correlation in perovskite solar cells: One-step versus two-step deposition of CH3NH3PbI3

    Directory of Open Access Journals (Sweden)

    Jeong-Hyeok Im

    2014-08-01

    Full Text Available Perovskite CH3NH3PbI3 light absorber is deposited on the mesoporous TiO2 layer via one-step and two-step coating methods and their photovoltaic performances are compared. One-step coating using a solution containing CH3NH3I and PbI2 shows average power conversion efficiency (PCE of 7.5%, while higher average PCE of 13.9% is obtained from two-step coating method, mainly due to higher voltage and fill factor. The coverage, pore-filling, and morphology of the deposited perovskite are found to be critical in photovoltaic performance of the mesoporous TiO2 based perovskite solar cells.

  20. Building materials. VOC emissions, diffusion behaviour and implications from their use.

    Science.gov (United States)

    Katsoyiannis, Athanasios; Leva, Paolo; Barrero-Moreno, Josefa; Kotzias, Dimitrios

    2012-10-01

    Five cement- and five lime-based building materials were examined in an environmental chamber for their emissions of Volatile Organic Compounds (VOCs). Typical VOCs were below detection limits, whereas not routinely analysed VOCs, like neopentyl glycol (NPG), dominated the cement-based products emissions, where, after 72 h, it was found to occur, in levels as high as 1400 μg m(-3), accounting for up to 93% of total VOCs. The concentrations of NPG were not considerably changed between the 24 and 72 h of sampling. The permeability of building materials was assessed through experiments with a dual environmental chamber; it was shown that building materials facilitate the diffusion of chemicals through their pores, reaching equilibrium relatively fast (6 h). Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Assessment of Exposure to VOCs among Pregnant Women in the National Children's Study.

    Science.gov (United States)

    Boyle, Elizabeth Barksdale; Viet, Susan M; Wright, David J; Merrill, Lori S; Alwis, K Udeni; Blount, Benjamin C; Mortensen, Mary E; Moye, John; Dellarco, Michael

    2016-03-29

    Epidemiologic studies can measure exposure to volatile organic compounds (VOCs) using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children's Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS). We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking) and by observations by a trained data collector (presence of scented products in homes). We found several significant (p < 0.01) relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite N

  2. Effect of NaCl-Stress on Metabolism of NO3-, NH4+ and NO2- at Several Rice Varieties

    Directory of Open Access Journals (Sweden)

    M Zulman Harja Utama

    2010-09-01

    Full Text Available This study was conducted to evaluate the effect of NaCl-stress on metabolism of NO3-, NH4+ and NO2- at several rice varieties. The results showed that an addition of NaCl had lesser effect on NaCl-tolerant varieties as compared to NaCl-sensitive in term of reduction in NO3-, NH4+, and NO2- uptake. Rice adaptation ability to NaCl stress occurred through the mechanism of NO3-, NH4+, and N02- metabolism physiology. It was indicated by the difference concentration of NO3-, NH4+ and N02- between the tolerant (Cisadane, moderate (Batang Lembang, Rendah Kuning, and Batang Piaman and sensitive (IR 66 varieties. Concentration of NH4+ and N02- of tolerant rice (Cisadane at NaCl treatment were about 1.16 and 2.6 times higher than that at control, respectively, while concentration of NO3- was only 0.03 times lower than control. In contrast, concentration of NO3-, NH4+, and N02- of sensitive rice (IR 66, were about 0.09, 0.27, and 0.41 times lower than that in control respecting at NaCl treatment, respectively.

  3. Kinetics of selected elementary reactions of NH(a{sup 1}{delta}) or ND(a{sup {delta}}), NH(X{sup 3}{sigma}{sup -}) or ND(X{sup 3}{sigma}{sup -}) and NH{sub 2}(X), NHD(X), NH{sub 2}(X) radicals; Untersuchung der Kinetik ausgewaehlter Elementarreaktionen von NH(a{sup 1}{delta})- bzw. ND(a{sup 1}{delta})-, NH(X{sup 3}{sigma}{sup -})- bzw. ND(X{sup 3}{sigma}{sup -})- und NH{sub 2}(X)-, NHD(X)-, ND{sub 2}(X)-Radikalen

    Energy Technology Data Exchange (ETDEWEB)

    Adam, L.

    2002-02-01

    The elementary reactions of the NH and ND radicals in the ground state and the first excited state with H({sup 2}S) atoms and with molecules containing hydrogen and fluorine element bonds were investigated in the gaseous phase at a pressure of p = 7-80 bar. The elementary reactions of the NH{sub 2}, NHD and ND{sub 2} radicals in the ground state with hydrogen halides in the gaseous phase were investigated as well. [German] Die Elementarreaktionen des NH- bzw. ND-Radikals im Elektronengrundzustand und im ersten elektronisch angeregten Zustand mit H({sup 2}S)-Atomen und mit Molekuelen, die Wasserstoff- und Fluor-Elementbindungen besitzen, wurden in der Gasphase bei einem Druck von p = 7 - 80 mbar untersucht. Weiterhin wurden die Elementarreaktionen der NH{sub 2}-, NHD- bzw. ND{sub 2}-Radikale im Elektronengrundzustand mit Halogenwasserstoffen in der Gasphase untersucht. (orig.)

  4. Adsorption behavior of NH3 and NO2 molecules on stanene and stanane nanosheets - A density functional theory study

    Science.gov (United States)

    Nagarajan, V.; Chandiramouli, R.

    2018-03-01

    Using density functional theory method, we investigate the adsorption properties of NH3 and NO2 molecules on stanene and stanane nanosheets. The adsorption of molecules is explored based on the charge transfer, energetics, energy band gap and average energy gap variation. Moreover, the optimal adsorption sites of NH3 and NO2 molecules are identified on stanene and stanane nanosheets. Besides, the state-of-the-art provides the key features for the development of chemi-resistive nanosensor based on stanene and stanane nanosheets upon adsorption of NH3 and NO2 molecules. Furthermore, the study shows that adsorption of NO2 molecules is more prominent rather than NH3 molecules.

  5. Reconstructive phase transition in (NH4)3TiF7 accompanied by the ordering of TiF6 octahedra.

    Science.gov (United States)

    Molokeev, Maxim; Misjul, S V; Flerov, I N; Laptash, N M

    2014-12-01

    An unusual phase transition P4/mnc → Pa\\bar 3 has been detected after cooling the (NH4)3TiF7 compound. Some TiF6 octahedra, which are disordered in the room-temperature tetragonal structure, become ordered in the low-temperature cubic phase due to the disappearance of the fourfold axis. Other TiF6 octahedra undergo large rotations resulting in huge displacements of the F atoms by 1.5-1.8 Å that implies a reconstructive phase transition. It was supposed that phases P4/mbm and Pm\\bar 3m could be a high-temperature phase and a parent phase, respectively, in (NH4)3TiF7. Therefore, the sequence of phase transitions can be written as Pm\\bar 3m → P4/mbm → P4/mnc → Pa\\bar 3. The interrelation between (NH4)3TiF7, (NH4)3GeF7 and (NH4)3PbF7 is found, which allows us to suppose phase transitions in relative compounds.

  6. Comparison of decomposition characteristics between aromatic and aliphatic VOCs using electron beam

    International Nuclear Information System (INIS)

    Kim, Jo-Chun

    2011-01-01

    The removal efficiency of n-decane (C 10 H 22 ) by electron beam was the highest among aliphatic VOCs of concern, and that of n-hexane (C 6 H 14 ), n-butane (C 4 H 10 ), and methane (CH 4 ) followed. On the other hand, in terms of aromatic VOC decomposition efficiencies, benzene (C 6 H 6 ) decomposition was the lowest and that of toluene (C 7 H 8 ), ethylbenzene (C 8 H 10 ), and p-xylene (C 8 H 10 ) were similar. It was also found that there was increase in by-product (untreated VOC, CO, CO 2 , O 3 , and other compounds) formation as well as all VOC removal efficiencies. It was demonstrated that the removal efficiency of VOC increased as its concentration decreased and the irradiation dose increased. In addition, low removal efficiency was observed because helium was relatively stable compared to the other gases, and nothing but electrons produced by electron accelerator reacted with VOC. It was also found that relative humidity had some effects on the decomposition rates of VOC. The removal efficiency at the 100% RH condition was slightly higher than that at 7.4% RH (dry condition) due to OH radical formation. (author)

  7. Quantitative assessment of industrial VOC emissions in China: Historical trend, spatial distribution, uncertainties, and projection

    Science.gov (United States)

    Zheng, Chenghang; Shen, Jiali; Zhang, Yongxin; Huang, Weiwei; Zhu, Xinbo; Wu, Xuecheng; Chen, Linghong; Gao, Xiang; Cen, Kefa

    2017-02-01

    The temporal trends of industrial volatile organic compound (VOC) emissions was comprehensively summarized for the 2011 to 2013 period, and the projections for 2020 to 2050 for China were set. The results demonstrate that industrial VOC emissions in China increased from 15.3 Tg in 2011 to 29.4 Tg in 2013 at an annual average growth rate of 38.3%. Guangdong (3.45 Tg), Shandong (2.85 Tg), and Jiangsu (2.62 Tg) were the three largest contributors collectively accounting for 30.4% of the national total emissions in 2013. The top three average industrial VOC emissions per square kilometer were Shanghai (247.2 ton/km2), Tianjin (62.8 ton/km2), and Beijing (38.4 ton/km2), which were 12-80 times of the average level in China. The data from the inventory indicate that the use of VOC-containing products, as well as the production and use of VOCs as raw materials, as well as for storage and transportation contributed 75.4%, 10.3%, 9.1%, and 5.2% of the total emissions, respectively. ArcGIS was used to display the remarkable spatial distribution variation by allocating the emission into 1 km × 1 km grid cells with a population as surrogate indexes. Combined with future economic development and population change, as well as implementation of policy and upgrade of control technologies, three scenarios (scenarios A, B, and C) were set to project industrial VOC emissions for the years 2020, 2030, and 2050, which present the industrial VOC emissions in different scenarios and the potential of reducing emissions. Finally, the result shows that the collaborative control policies considerably influenced industrial VOC emissions.

  8. Increasing Hydrogen Density with the Cation-Anion Pair BH4−-NH4+ in Perovskite-Type NH4Ca(BH43

    Directory of Open Access Journals (Sweden)

    Pascal Schouwink

    2015-08-01

    Full Text Available A novel metal borohydride ammonia-borane complex Ca(BH42·NH3BH3 is characterized as the decomposition product of the recently reported perovskite-type metal borohydride NH4Ca(BH43, suggesting that ammonium-based metal borohydrides release hydrogen gas via ammonia-borane-complexes. For the first time the concept of proton-hydride interactions to promote hydrogen release is applied to a cation-anion pair in a complex metal hydride. NH4Ca(BH43 is prepared mechanochemically from Ca(BH42 and NH4Cl as well as NH4BH4 following two different protocols, where the synthesis procedures are modified in the latter to solvent-based ball-milling using diethyl ether to maximize the phase yield in chlorine-free samples. During decomposition of NH4Ca(BH43 pure H2 is released, prior to the decomposition of the complex to its constituents. As opposed to a previously reported adduct between Ca(BH42 and NH3BH3, the present complex is described as NH3BH3-stuffed α-Ca(BH42.

  9. Investigation of the molecular motions in Cd(NH/sub 3/)/sub 6/Cl/sub 2/ by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pislewski, N [Polska Akademia Nauk, Poznan. Inst. Fizyki Molekularnej; Ferris, L T.H. [University Coll., London (UK). Dept. of Chemistry

    1981-07-01

    NMR results are reported for intramolecular motion in Cd(NH/sub 3/)/sub 6/Cl/sub 2/. Below the 180 K phase transition, the motion of the NH/sub 3/ groups is well described by the Hilt-Hubbard theory with an activation energy of 9.63 kJ/mol. The inter-proton distance in NH/sub 3/ determined from relaxational measurements is 0.161 nm. Several K below and above the transition point, two phases with different spin-lattice relaxation times coexist.

  10. Towards a carbon independent and CO2-free electrochemical membrane process for NH3 synthesis.

    Science.gov (United States)

    Kugler, K; Ohs, B; Scholz, M; Wessling, M

    2014-04-07

    Ammonia is exclusively synthesized by the Haber-Bosch process starting from precious carbon resources such as coal or CH4. With H2O, H2 is produced and with N2, NH3 can be synthesized at high pressures and temperatures. Regrettably, the carbon is not incorporated into NH3 but emitted as CO2. Valuable carbon sources are consumed which could be used otherwise when carbon sources become scarce. We suggest an alternative process concept using an electrochemical membrane reactor (ecMR). A complete synthesis process with N2 production and downstream product separation is presented and evaluated in a multi-scale model to quantify its energy consumption. A new micro-scale ecMR model integrates mass, species, heat and energy balances with electrochemical conversions allowing further integration into a macro-scale process flow sheet. For the anodic oxidation reaction H2O was chosen as a ubiquitous H2 source. Nitrogen was obtained by air separation which combines with protons from H2O to give NH3 using a hypothetical catalyst recently suggested from DFT calculations. The energy demand of the whole electrochemical process is up to 20% lower than the Haber-Bosch process using coal as a H2 source. In the case of natural gas, the ecMR process is not competitive under today's energy and resource conditions. In future however, the electrochemical NH3 synthesis might be the technology-of-choice when coal is easily accessible over natural gas or limited carbon sources have to be used otherwise but for the synthesis of the carbon free product NH3.

  11. Volatile Organic Compound (VOC Removal by Vapor Permeation at Low VOC Concentrations: Laboratory Scale Results and Modeling for Scale Up

    Directory of Open Access Journals (Sweden)

    Philippe Moulin

    2011-03-01

    Full Text Available Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs (toluene-propylene-butadiene from air was performed using a poly dimethyl siloxane (PDMS/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10−4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID. The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

  12. The bovine TRPV3 as a pathway for the uptake of Na+, Ca2+, and NH4.

    Science.gov (United States)

    Schrapers, Katharina T; Sponder, Gerhard; Liebe, Franziska; Liebe, Hendrik; Stumpff, Friederike

    2018-01-01

    Absorption of ammonia from the gastrointestinal tract results in problems that range from hepatic encephalopathy in humans to poor nitrogen efficiency of cattle with consequences for the global climate. Previous studies on epithelia and cells from the native ruminal epithelium suggest functional involvement of the bovine homologue of TRPV3 (bTRPV3) in ruminal NH4+ transport. Since the conductance of TRP channels to NH4+ has never been studied, bTRPV3 was overexpressed in HEK-293 cells and investigated using the patch-clamp technique and intracellular calcium imaging. Control cells contained the empty construct. Divalent cations blocked the conductance for monovalent cations in both cell types, with effects higher in cells expressing bTRPV3. In bTRPV3 cells, but not in controls, menthol, thymol, carvacrol, or 2-APB stimulated whole cell currents mediated by Na+, Cs+, NH4+, and K+, with a rise in intracellular Ca2+ observed in response to menthol. While only 25% of control patches showed single-channel events (with a conductance of 40.8 ± 11.9 pS for NH4+ and 25.0 ± 5.8 pS for Na+), 90% of bTRPV3 patches showed much larger conductances of 127.8 ± 4.2 pS for Na+, 240.1 ± 3.6 pS for NH4+, 34.0 ± 1.7 pS for Ca2+, and ~ 36 pS for NMDG+. Open probability, but not conductance, rose with time after patch excision. In conjunction with previous research, we suggest that bTRPV3 channels may play a role in the transport of Na+, K+, Ca2+ and NH4+ across the rumen with possible repercussions for understanding the function of TRPV3 in other epithelia.

  13. The bovine TRPV3 as a pathway for the uptake of Na+, Ca2+, and NH4+

    Science.gov (United States)

    Liebe, Franziska; Liebe, Hendrik

    2018-01-01

    Absorption of ammonia from the gastrointestinal tract results in problems that range from hepatic encephalopathy in humans to poor nitrogen efficiency of cattle with consequences for the global climate. Previous studies on epithelia and cells from the native ruminal epithelium suggest functional involvement of the bovine homologue of TRPV3 (bTRPV3) in ruminal NH4+ transport. Since the conductance of TRP channels to NH4+ has never been studied, bTRPV3 was overexpressed in HEK-293 cells and investigated using the patch-clamp technique and intracellular calcium imaging. Control cells contained the empty construct. Divalent cations blocked the conductance for monovalent cations in both cell types, with effects higher in cells expressing bTRPV3. In bTRPV3 cells, but not in controls, menthol, thymol, carvacrol, or 2-APB stimulated whole cell currents mediated by Na+, Cs+, NH4+, and K+, with a rise in intracellular Ca2+ observed in response to menthol. While only 25% of control patches showed single-channel events (with a conductance of 40.8 ± 11.9 pS for NH4+ and 25.0 ± 5.8 pS for Na+), 90% of bTRPV3 patches showed much larger conductances of 127.8 ± 4.2 pS for Na+, 240.1 ± 3.6 pS for NH4+, 34.0 ± 1.7 pS for Ca2+, and ~ 36 pS for NMDG+. Open probability, but not conductance, rose with time after patch excision. In conjunction with previous research, we suggest that bTRPV3 channels may play a role in the transport of Na+, K+, Ca2+ and NH4+ across the rumen with possible repercussions for understanding the function of TRPV3 in other epithelia. PMID:29494673

  14. Crystallographic Investigations into Properties of Acentric Hybrid Perovskite Single Crystals NH(CH3)3SnX3(X = Cl, Br)

    KAUST Repository

    Dang, Yangyang; Zhong, Cheng; Zhang, Guodong; Ju, Dianxing; Wang, Lei; Xia, Shengqing; Xia, Haibing; Tao, Xutang

    2016-01-01

    substitute for the lead in the halides perovskites and solving the ambiguous crystal structures and phase transition of NH(CH3)3SnX3 (X = Cl, Br). Here, we report the bulk crystal growths and different crystal morphologies of orthorhombic hybrid perovskites

  15. New Type of 2D Perovskites with Alternating Cations in the Interlayer Space, (C(NH 2 ) 3 )(CH 3 NH 3 ) n Pb n I 3n+1 : Structure, Properties, and Photovoltaic Performance

    Energy Technology Data Exchange (ETDEWEB)

    Soe, Chan Myae Myae; Stoumpos, Constantinos C.; Kepenekian, Mikaël; Traoré, Boubacar; Tsai, Hsinhan; Nie, Wanyi; Wang, Binghao; Katan, Claudine; Seshadri, Ram; Mohite, Aditya D.; Even, Jacky; Marks, Tobin J.; Kanatzidis, Mercouri G. (UCSB); (NWU); (LANL); (CNRS-UMR)

    2017-11-01

    We present the new homologous series (C(NH2)3)(CH3NH3)nPbnI3n+1 (n = 1, 2, 3) of layered 2D perovskites. Structural characterization by single-crystal X-ray diffraction reveals that these compounds adopt an unprecedented structure type, which is stabilized by the alternating ordering of the guanidinium and methylammonium cations in the interlayer space (ACI). Compared to the more common Ruddlesden–Popper (RP) 2D perovskites, the ACI perovskites have a different stacking motif and adopt a higher crystal symmetry. The higher symmetry of the ACI perovskites is expressed in their physical properties, which show a characteristic decrease of the bandgap with respect to their RP perovskite counterparts with the same perovskite layer thickness (n). The compounds show a monotonic decrease in the optical gap as n increases: Eg = 2.27 eV for n = 1 to Eg = 1.99 eV for n = 2 and Eg = 1.73 eV for n = 3, which show slightly narrower gaps compared to the corresponding RP perovskites. First-principles theoretical electronic structure calculations confirm the experimental optical gap trends suggesting that the ACI perovskites are direct bandgap semiconductors with wide valence and conduction bandwidths. To assess the potential of the ACI perovskites toward solar cell applications, we studied the (C(NH2)3)(CH3NH3)3Pb3I10 (n = 3) compound. Compact thin films from the (C(NH2)3)(CH3NH3)3Pb3I10 compound with excellent surface coverage can be obtained from the antisolvent dripping method. Planar photovoltaic devices from optimized ACI perovskite films yield a power-conversion-efficiency of 7.26% with a high open-circuit voltage of ~1 V and a striking fill factor of ~80%.

  16. On One Approach to TSP Structural Stability

    Directory of Open Access Journals (Sweden)

    Evgeny Ivanko

    2014-01-01

    Full Text Available In this paper we study an inverse approach to the traveling salesman reoptimization problem. Namely, we consider the case of the addition of a new vertex to the initial TSP data and fix the simple “adaptation” algorithm: the new vertex is inserted into an edge of the optimal tour. In the paper we consider the conditions describing the vertexes that can be inserted by this algorithm without loss of optimality, study the properties of stability areas, and address several model applications.

  17. Different fates of deposited NH4+ and NO3- in a temperate forest in northeast China: a 15 N tracer study.

    Science.gov (United States)

    Liu, Jun; Peng, Bo; Xia, Zongwei; Sun, Jianfei; Gao, Decai; Dai, Weiwei; Jiang, Ping; Bai, Edith

    2017-06-01

    Increasing atmospheric reactive nitrogen (N) deposition due to human activities could change N cycling in terrestrial ecosystems. However, the differences between the fates of deposited NH4+ and NO3- are still not fully understood. Here, we investigated the fates of deposited NH4+ and NO3-, respectively, via the application of 15 NH 4 NO 3 and NH 4 15 NO 3 in a temperate forest ecosystem. Results showed that at 410 days after tracer application, most 15NH4+ was immobilized in litter layer (50 ± 2%), while a considerable amount of 15NO3- penetrated into 0-5 cm mineral soil (42 ± 2%), indicating that litter layer and 0-5 cm mineral soil were the major N sinks of NH4+ and NO3-, respectively. Broad-leaved trees assimilated more 15 N under NH 4 15 NO 3 treatment compared to under 15 NH 4 NO 3 treatment, indicating their preference for NO3--N. At 410 days after tracer application, 16 ± 4% added 15 N was found in aboveground biomass under 15NO3- treatment, which was twice more than that under 15NH4+ treatment (6 ± 1%). At the same time, approximately 80% added 15 N was recovered in soil and plants under both treatments, which suggested that this forest had high potential for retention of deposited N. These results provided evidence that there were great differences between the fates of deposited NH4+ and NO3-, which could help us better understand the mechanisms and capability of forest ecosystems as a sink of reactive nitrogen. © 2016 John Wiley & Sons Ltd.

  18. MEMBRANE BIOTREATMENT OF VOC-LADEN AIR

    Science.gov (United States)

    The paper discusses membrane biotreatment of air laden with volatile organic compounds (VOCs). Microporous flat-sheet and hollow-fiber membrane contactors were used to support air-liquid mass transfer interfaces. These modules were used in a two-step process to transfer VOCs fr...

  19. Nematicidal effect of volatile organic compounds (VOCs on the plant-parasitic nematode Meloidogyne javanica

    Directory of Open Access Journals (Sweden)

    Mauricio Batista Fialho

    2012-06-01

    Full Text Available Previous studies have demonstrated that volatile organic compounds (VOCs, produced by the yeast Saccharomyces cerevisiae, were able to inhibit the development of phytopathogenic fungi. In this context, the nematicidal potential of the synthetic mixture of VOCs, constituted of alcohols and esters, was evaluated for the control of the root-knot nematode Meloidogyne javanica, which causes losses to crops of high economic value. The fumigation of substrate containing second-stage juveniles with VOCs exhibited nematicidal effect higher than 30% for the lowest concentration tested (33.3 µL g-1 substrate, whereas at 66.6 and 133.3 µL g-1 substrate, the nematode mortality was 100%. The present results stimulate other studies on VOCs for nematode management.

  20. Ambient Volatile Organic Compounds (VOCs) pollution in Isolo ...

    African Journals Online (AJOL)

    The adsorbed VOCs were desorbed with carbondisulphide (CS2) and the solution analysed using Gas Chromatography (GC) fitted with Flame Ionization Detector (FID). The results from analysis of the air samples collected showed that twenty-six (26) VOCs were captured in Isolo Industrial area. The VOCs were classified ...

  1. Heterolytic cleavage of ammonia N-H bond by bifunctional activation in silica-grafted single site Ta(V) imido amido surface complex. Importance of the outer sphere NH3 assistance

    KAUST Repository

    Gouré , Eric; Avenier, Priscilla; Solá ns, Xavier Luis; Veyre, Laurent; Baudouin, Anne Christine; Kaya, Yasemin; Taoufik, Mostafa; Basset, Jean-Marie; Eisenstein, Odile; Quadrelli, Elsje Alessandra

    2011-01-01

    and imido groups have accessible energy barriers. The energy barrier for the ammonia N-H activation by the Ta-amido group is energetically preferred relative to the Ta-imido group. The importance of excess NH3 for getting full isotope scrambling

  2. VOC Control in Kraft Mills; FINAL

    International Nuclear Information System (INIS)

    Zhu, J.Y.; Chai, X.-S.; Edwards, L.L.; Gu, Y.; Teja, A.S.; Kirkman, A.G.; Pfromm, P.H.; Rezac, M.E.

    2001-01-01

    The formation of volatile organic compounds (VOCs), such as methanol, in kraft mills has been an environmental concern. Methanol is soluble in water and can increase the biochemical oxygen demand. Furthermore, it can also be released into atmosphere at the process temperatures of kraft mill-streams. The Cluster Rule of the EPA now requires the control of the release of methanol in pulp and paper mills. This research program was conducted to develop a computer simulation tool for mills to predict VOC air emissions. To achieve the objective of the research program, much effort was made in the development of analytical techniques for the analysis of VOC and determination of vapor liquid partitioning coefficient of VOCs in kraft mill-streams using headspace gas chromatography. With the developed analytical tool, methanol formation in alkaline pulping was studied in laboratory to provide benchmark data of the amount of methanol formation in pulping in kraft mills and for the validation of VOC formation and vapor-liquid equilibrium submodels. Several millwide air and liquid samplings were conducted using the analytical tools developed to validate the simulation tool. The VOC predictive simulation model was developed based on the basic chemical engineering concepts, i.e., reaction kinetics, vapor liquid equilibrium, combined with computerized mass and energy balances. Four kraft mill case studies (a continuous digester, two brownstock washing lines, and a pre-evaporator system) are presented and compared with mill measurements. These case studies provide valuable, technical information for issues related to MACT I and MACT II compliance, such as condensate collection and Clean-Condensate-Alternatives (CCA)

  3. Source profiles of volatile organic compounds (VOCs) measured in China: Part I

    Science.gov (United States)

    Liu, Ying; Shao, Min; Fu, Linlin; Lu, Sihua; Zeng, Limin; Tang, Dagang

    The profiles of major volatile organic compound (VOC) sources in China, including vehicle exhaust, gasoline vapor, paint, asphalt, industrial and residential coal burning, biomass burning, and the petrochemical industry, were experimentally determined. Source samples were taken using a dilution chamber for mobile and stationary sources, biomass burning in an actual Chinese farmer's house, and ambient air in a petrochemical industrial area. The concentrations of 92 VOC species were quantified using canister sampling and a gas chromatography-flame ionization detection/mass spectrometry system, and VOC source profiles were developed for source apportionment of VOCs in the Pearl River Delta region. Based on the measurement of source profiles, possible tracers for various emission sources were identified; e.g., 2-methylpentane and 1,3-butadiene could be used as tracers for vehicle exhaust; the characteristic compounds of architectural coating were aromatics such as toluene and m, p-xylene; the light hydrocarbons, namely n-butane, trans-2-butene, and n-pentane, dominated the composition of gasoline vapor; and n-nonane, n-decane, and n-undecane were found to be typical of diesel vapor and asphalt application processes. As different emission sources are characterized by overlapping VOC species, the ratio of possible VOC tracers could be used to assess the contribution of various sources. The ratios between n-butane and isobutane, 1,3-butadiene and isoprene, and the ratios of aromatics (e.g., toluene to benzene and ethylbenzene to m, p-xylene) in the measured sources were compared.

  4. INTEGRATING CASE-BASED REASONING, KNOWLEDGE-BASED APPROACH AND TSP ALGORITHM FOR MINIMUM TOUR FINDING

    Directory of Open Access Journals (Sweden)

    Hossein Erfani

    2009-07-01

    Full Text Available Imagine you have traveled to an unfamiliar city. Before you start your daily tour around the city, you need to know a good route. In Network Theory (NT, this is the traveling salesman problem (TSP. A dynamic programming algorithm is often used for solving this problem. However, when the road network of the city is very complicated and dense, which is usually the case, it will take too long for the algorithm to find the shortest path. Furthermore, in reality, things are not as simple as those stated in AT. For instance, the cost of travel for the same part of the city at different times may not be the same. In this project, we have integrated TSP algorithm with AI knowledge-based approach and case-based reasoning in solving the problem. With this integration, knowledge about the geographical information and past cases are used to help TSP algorithm in finding a solution. This approach dramatically reduces the computation time required for minimum tour finding.

  5. Emission factor of ammonia (NH3) from on-road vehicles in China: tunnel tests in urban Guangzhou

    Science.gov (United States)

    Liu, Tengyu; Wang, Xinming; Wang, Boguang; Ding, Xiang; Deng, Wei; Lü, Sujun; Zhang, Yanli

    2014-05-01

    Ammonia (NH3) is the primary alkaline gas in the atmosphere that contributes to formation of secondary particles. Emission of NH3 from vehicles, particularly gasoline powered light duty vehicles equipped with three-way catalysts, is regarded as an important source apart from emissions from animal wastes and soils, yet measured emission factors for motor vehicles are still not available in China, where traffic-related emission has become an increasingly important source of air pollutants in urban areas. Here we present our tunnel tests for NH3 from motor vehicles under ‘real world conditions’ in an urban roadway tunnel in Guangzhou, a central city in the Pearl River Delta (PRD) region in south China. By attributing all NH3 emissions in the tunnel to light-duty gasoline vehicles, we obtained a fuel-based emission rate of 2.92 ± 0.18 g L-1 and a mileage-based emission factor of 229.5 ± 14.1 mg km-1. These emission factors were much higher than those measured in the United States while measured NO x emission factors (7.17 ± 0.60 g L-1 or 0.56 ± 0.05 g km-1) were contrastingly near or lower than those previously estimated by MOBILE/PART5 or COPERT IV models. Based on the NH3 emission factors from this study, on-road vehicles accounted for 8.1% of NH3 emissions in the PRD region in 2006 instead of 2.5% as estimated in a previous study using emission factors taken from the Emission Inventory Improvement Program (EIIP) in the United States.

  6. Emission factor of ammonia (NH3) from on-road vehicles in China: tunnel tests in urban Guangzhou

    International Nuclear Information System (INIS)

    Liu, Tengyu; Wang, Xinming; Ding, Xiang; Deng, Wei; Lü, Sujun; Zhang, Yanli; Wang, Boguang

    2014-01-01

    Ammonia (NH 3 ) is the primary alkaline gas in the atmosphere that contributes to formation of secondary particles. Emission of NH 3 from vehicles, particularly gasoline powered light duty vehicles equipped with three-way catalysts, is regarded as an important source apart from emissions from animal wastes and soils, yet measured emission factors for motor vehicles are still not available in China, where traffic-related emission has become an increasingly important source of air pollutants in urban areas. Here we present our tunnel tests for NH 3 from motor vehicles under ‘real world conditions’ in an urban roadway tunnel in Guangzhou, a central city in the Pearl River Delta (PRD) region in south China. By attributing all NH 3 emissions in the tunnel to light-duty gasoline vehicles, we obtained a fuel-based emission rate of 2.92 ± 0.18 g L −1 and a mileage-based emission factor of 229.5 ± 14.1 mg km −1 . These emission factors were much higher than those measured in the United States while measured NO x emission factors (7.17 ± 0.60 g L −1 or 0.56 ± 0.05 g km −1 ) were contrastingly near or lower than those previously estimated by MOBILE/PART5 or COPERT IV models. Based on the NH 3 emission factors from this study, on-road vehicles accounted for 8.1% of NH 3 emissions in the PRD region in 2006 instead of 2.5% as estimated in a previous study using emission factors taken from the Emission Inventory Improvement Program (EIIP) in the United States. (letter)

  7. Productions of Volatile Organic Compounds (VOCs) in Surface Waters from Reactions with Atmospheric Ozone

    Science.gov (United States)

    Hopkins, Frances; Bell, Thomas; Yang, Mingxi

    2017-04-01

    Ozone (O3) is a key atmospheric oxidant, greenhouse gas and air pollutant. In marine environments, some atmospheric ozone is lost by reactions with aqueous compounds (e.g. dissolved organic material, DOM, dimethyl sulfide, DMS, and iodide) near the sea surface. These reactions also lead to formations of volatile organic compounds (VOCs). Removal of O3 by the ocean remains a large uncertainty in global and regional chemical transport models, hampering coastal air quality forecasts. To better understand the role of the ocean in controlling O3 concentrations in the coastal marine atmosphere, we designed and implemented a series of laboratory experiments whereby ambient surface seawater was bubbled with O3-enriched, VOC-free air in a custom-made glass bubble equilibration system. Gas phase concentrations of a range of VOCs were monitored continuously over the mass range m/z 33 - 137 at the outflow of the bubble equilibrator by a proton transfer reaction - mass spectrometer (PTR-MS). Gas phase O3 was also measured at the input and output of the equilibrator to monitor the uptake due to reactions with dissolved compounds in seawater. We observed consistent productions of a variety of VOCs upon reaction with O3, notably isoprene, aldehydes, and ketones. Aqueous DMS is rapidly removed from the reactions with O3. To test the importance of dissolved organic matter precursors, we added increasing (milliliter) volumes of Emiliania huxleyi culture to the equilibrator filled with aged seawater, and observed significant linear increases in gas phase concentrations of a number of VOCs. Reactions between DOM and O3 at the sea-air interface represent a potentially significant source of VOCs in marine air and a sink of atmospheric O3.

  8. VOC emissions chambers

    Data.gov (United States)

    Federal Laboratory Consortium — In order to support the development of test methods and reference materials for volatile organic compounds (VOC) emissions from building materials and furnishings,...

  9. Surface-exchange of NOx and NH3 above a winter wheat field in the Yangtze Delta, China

    Institute of Scientific and Technical Information of China (English)

    FANG Shuan-gxi; ZHANG Yi; MU Yu-jing

    2006-01-01

    A four-dynamic-chamber system was constructed to measure NOx and NH3 surface-exchange between a typical wheat field and the fluxes of NO2 and NH3 were negatively correlated with their ambient concentrations during the investigated period. The compensation point of NO2 between the wheat field and the atmosphere was 11.9 μg/m3. The emissions of NO-N and NH3-N from the urea applied to the wheat field were 2.3% and 0.2%, respectively, which indicated that the main pathway of N loss from the investigated winter wheat field was NO. Application of a mixture of urea and lignin increased the emissions of NO, but also greatly increased the yield of the winter wheat.

  10. Comparisons of 13NH3, 18FDG PET and MRS in the presurgical evaluation of intractable epilepsy

    International Nuclear Information System (INIS)

    Cai Li; Gao Shuo; Li Dacheng; Li Zugui

    2004-01-01

    Purpose: Surgery offers a high chance of seizure-free outcome in patients with intractable epilepsy. Other than EEG, several functional and morphologic imaging Methods are used to define the spatial seizure origin. Blood flow perfusion and metabolic abnormalities in those patients are well described respectively. Proton MR spectroscopy (MRS) is still in the early stages in the evaluation of epilepsy. Comparisons with 13NH3 perfusion, 18FDG metabolic PET imaging and MRS in the same patients have rarely been documented. The present study was undertaken to compare the merits of 13NH3 PET, 18FDG PET, magnetic resonance imaging (MRI) and MRS for the lateralization of seizure foci. Methods: Preoperative long-term-EEG, Video-EEG, 13NH3 perfusion PET, 18FDG metabolic PET, MRI, MRS and neuropsychological assessment were performed in 15 patients with intractable epilepsy within 2 weeks(mean age=24.8 years, range 4 to 44 years; mean epilepsy duration=11 years, range 2 to 36 years), who received electrocorticography (ECoG). Antiepileptic drug (AED) was stopped taking at least 2 days before PET scanning. 13NH3 and FDG PET was performed in one day and analyzed with a region of interest template. An absolute asymmetry index, |AI|, greater than 0.15 was considered abnormal. 13 subjects were underwent MRS obtained from the hippocampus bilaterally, who had a presumptive temporal seizure focus based on seizure semiology, video-EEG and MRI. Metabolite ratio of NAA/Cho+Cr was calculated from the relative peak height measurements. An NAA/Cho+Cr ratio of 0.72 or less was regarded as abnormal. All the examination Results were compared with EcoG to evaluate their values of seizure foci lateraliaztion. Results: 1. The results were divided into ictal (n=4) and interictal (n= 11) groups. In the ictal group, the sensitivity of 13NH3 PET and 18FDG PET were both 100%(4/4), and 13NH3 PET showed bilateral hippocampus hyperfusion foci in one case. In the interictal group, 13NH3 PET correctly

  11. Biochar produced from oak sawdust by Lanthanum (La)-involved pyrolysis for adsorption of ammonium (NH4(+)), nitrate (NO3(-)), and phosphate (PO4(3-)).

    Science.gov (United States)

    Wang, Zhanghong; Guo, Haiyan; Shen, Fei; Yang, Gang; Zhang, Yanzong; Zeng, Yongmei; Wang, Lilin; Xiao, Hong; Deng, Shihuai

    2015-01-01

    A series of biochars were prepared by pyrolyzing oak sawdust with/without LaCl3 involvement at temperature of 300-600 °C, and approximate and ultimate analyses were carried out to check their basic characteristics. Meanwhile, the releases of readily soluble NH4(+), NO3(-) and PO4(3-) from biochars and the adsorption of NH4(+), NO3(-) and PO4(3-) by biochars were investigated. Results indicated that the involvement of LaCl3 in pyrolysis could advance the temperature of maximum mass loss by 10 °C compared with oak sawdust (CK), and potentially promoted biochar yield. Overall, the releases of readily soluble NH4(+), NO3(-) and PO4(3-) from biochars were negatively related to pyrolysis temperature, and the releases were greatly weakened by La-biochars. Additionally, the adsorption to NH4(+) can be promoted by the biochars produced at low temperature. On the contrary, the NO3(-) adsorption can be improved by increasing pyrolysis temperature. The highest PO4(3-) adsorption was achieved by the biochars produced at 500 °C. According to the results of adsorption isotherms, the maximum adsorption capacity of NH4(+), NO3(-) and PO4(3-) can be significantly promoted by 1.9, 11.2, and 4.5 folds using La-biochars. Based on the observations of FT-IR, SEM-EDS, and surface functional groups, the improvement of NH4(+) adsorption was potentially associated with the existing acidic function groups (phenolic-OH and carboxyl C=O). The increased basic functional groups on La-biochars were beneficial to improve NO3(-) and PO4(3-) adsorption. Besides, PO4(3-) adsorption was also potentially related to the formed La2O3. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. The removal of COD and NH3-N from atrazine production wastewater treatment using UV/O3: experimental investigation and kinetic modeling.

    Science.gov (United States)

    Jing, Liang; Chen, Bing; Wen, Diya; Zheng, Jisi; Zhang, Baiyu

    2018-01-01

    In this study, a UV/O 3 hybrid advanced oxidation system was used to remove chemical oxygen demand (COD), ammonia nitrogen (NH 3 -N), and atrazine (ATZ) from ATZ production wastewater. The removal of COD and NH 3 -N, under different UV and O 3 conditions, was found to follow pseudo-first-order kinetics with rate constants ranging from 0.0001-0.0048 and 0.0015-0.0056 min -1 , respectively. The removal efficiency of ATZ was over 95% after 180 min treatment, regardless the level of UV power. A kinetic model was further proposed to simulate the removal processes and to quantify the individual roles and contributions of photolysis, direct O 3 oxidation, and hydroxyl radical (OH·) induced oxidation. The experimental and kinetic modeling results agreed reasonably well with deviations of 12.2 and 13.1% for the removal of COD and NH 3 -N, respectively. Photolysis contributed appreciably to the degradation of ATZ, while OH· played a dominant role for the removal of both COD and NH 3 -N, especially in alkaline environments. This study provides insights into the treatment of ATZ containing wastewater using UV/O 3 and broadens the knowledge of kinetics of ozone-based advanced oxidation processes.

  13. DFT investigation of NH{sub 3}, PH{sub 3}, and AsH{sub 3} adsorptions on Sc-, Ti-, V-, and Cr-doped single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Buasaeng, Prayut; Rakrai, Wandee [Computational Chemistry Center for Nanotechnology and Department of Chemistry, Faculty of Science and Technology, Rajabhat Maha Sarakham University, Maha Sarakham, 44000 (Thailand); Wanno, Banchob [Center of Excellence for Innovation in Chemistry and Supramolecular Chemistry Research Unit, Department of Chemistry, Faculty of Science, Mahasarakham University, Maha Sarakham, 44150 (Thailand); Tabtimsai, Chanukorn, E-mail: tabtimsai.c@gmail.com [Computational Chemistry Center for Nanotechnology and Department of Chemistry, Faculty of Science and Technology, Rajabhat Maha Sarakham University, Maha Sarakham, 44000 (Thailand)

    2017-04-01

    Highlights: • Transition metal-doped single wall carbon nanotubes and their adsorption with NH{sub 3}, PH{sub 3} and AsH{sub 3} molecules were investigated using a DFT method. • Adsorptions of NH{sub 3}, PH{sub 3} and AsH{sub 3} molecules on pristine single wall carbon nanotubeswere improved by transition metal doping. • Structural and electronic properties of single wall carbon nanotubes were significantly changed by transition metal doping and gas adsorptions. - Abstract: The adsorption properties of ammonia (NH{sub 3}), phosphine (PH{sub 3}), and arsine (AsH{sub 3}) on pristine and transition metal- (TM = Sc, Ti, V, and Cr) doped (5,5) armchair single-walled carbon nanotubes (SWCNTs) were theoretically investigated. The geometric and electronic properties and adsorption abilities for the most stable configuration of NH{sub 3}, PH{sub 3}, and AsH{sub 3} adsorptions on pristine and TM-doped SWCNTs were calculated. It was found that the binding abilities of TMs to the SWCNT were in the order: Cr > V > Sc > Ti. However, the adsorption energy showed that the pristine SWCNT weakly adsorbed gas molecules and its electronic properties were also insensitive to gas molecules. By replacing a C atom with TM atoms, all doping can significantly enhance the adsorption energy of gas/SWCNT complexes and their adsorption ability was in the same order: NH{sub 3} > PH{sub 3} > AsH{sub 3}. A remarkable increase in adsorption energy and charge transfer of these systems was expected to induce significant changes in the electrical conductivity of the TM-doped SWCNTs. This work revealed that the sensitivity of SWCNT-based chemical gas adsorptions and sensors can be greatly improved by introducing an appropriate TM dopant. Accordingly, TM-doped SWCNTs are more suitable for gas molecule adsorptions and detections than the pristine SWCNT.

  14. Enhancement of NH3 gas sensitivity at room temperature by carbon nanotube-based sensor coated with Co nanoparticles.

    Science.gov (United States)

    Nguyen, Lich Quang; Phan, Pho Quoc; Duong, Huyen Ngoc; Nguyen, Chien Duc; Nguyen, Lam Huu

    2013-01-30

    Multi-walled carbon nanotube (MWCNT) film has been fabricated onto Pt-patterned alumina substrates using the chemical vapor deposition method for NH(3) gas sensing applications. The MWCNT-based sensor is sensitive to NH(3) gas at room temperature. Nanoclusters of Co catalysts have been sputtered on the surface of the MWCNT film to enhance gas sensitivity with respect to unfunctionalized CNT films. The gas sensitivity of Co-functionalized MWCNT-based gas sensors is thus significantly improved. The sensor exhibits good repeatability and high selectivity towards NH(3), compared with alcohol and LPG.

  15. Comparison of decomposition characteristics between aromatic and aliphatic VOCs using electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jo-Chun [Department of Environmental Engineering, Konkuk University, Seoul (Korea, Republic of)

    2011-07-01

    The removal efficiency of n-decane (C{sub 10}H{sub 22}) by electron beam was the highest among aliphatic VOCs of concern, and that of n-hexane (C{sub 6}H{sub 14}), n-butane (C{sub 4}H{sub 10}), and methane (CH{sub 4}) followed. On the other hand, in terms of aromatic VOC decomposition efficiencies, benzene (C{sub 6}H{sub 6}) decomposition was the lowest and that of toluene (C{sub 7}H{sub 8}), ethylbenzene (C{sub 8}H{sub 10}), and p-xylene (C{sub 8}H{sub 10}) were similar. It was also found that there was increase in by-product (untreated VOC, CO, CO{sub 2}, O{sub 3}, and other compounds) formation as well as all VOC removal efficiencies. It was demonstrated that the removal efficiency of VOC increased as its concentration decreased and the irradiation dose increased. In addition, low removal efficiency was observed because helium was relatively stable compared to the other gases, and nothing but electrons produced by electron accelerator reacted with VOC. It was also found that relative humidity had some effects on the decomposition rates of VOC. The removal efficiency at the 100% RH condition was slightly higher than that at 7.4% RH (dry condition) due to OH radical formation. (author)

  16. Towards validation of ammonia (NH3) measurements from the IASI satellite

    NARCIS (Netherlands)

    van Damme, M.; Clarisse, L.; Dammers, E.; Liu, X.; Nowak, J.; Clerbaux, C.; Flechard, C.; Galy-Lacaux, C.; Xu, W.W.; Neuman, J.; Tang, Y.; Sutton, M.; Erisman, J.W.; Coheur, P.F.

    2015-01-01

    Limited availability of ammonia (NH3) observations is currently a barrier for effective monitoring of the nitrogen cycle. It prevents a full understanding of the atmospheric processes in which this trace gas is involved and therefore impedes determining its related budgets. Since the end of 2007,

  17. New insights into Cu/SSZ-13 SCR catalyst acidity. Part I: Nature of acidic sites probed by NH 3 titration

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Jinyong; Gao, Feng; Kamasamudram, Krishna; Currier, Neal; Peden, Charles H. F.; Yezerets, Aleksey

    2017-04-01

    In this work we investigated an unusual acidity feature of a Cu/SSZ-13 catalyst used in selective catalytic reduction of NOx with NH3 (NH3-SCR). In particular, this catalyst showed two distinct NH3 desorption peaks in NH3-TPD measurements, in contrast to single, unresolved desorption peaks observed for other Cu-exchanged zeolites conventionally used in the SCR studies, including its isostructural but chemically different analogue Cu/SAPO-34. We further observed that the intensities of the two TPD peaks, which represented the amount of stored NH3, changed in opposite directions in response to progressive mild hydrothermal aging, while the total storage capacity was preserved. We proposed an explanation for this remarkable behavior, by using model reference samples and additional characterization techniques. At least three NH3 storage sites were identified: two distinct populations of Cu sites responsible for low-temperature NH3 storage, and Brønsted acid sites responsible for high-temperature NH3 storage. Contrary to the commonly accepted mechanism that Brønsted acid site loss during hydrothermal aging is driven by dealumination, we concluded that the decline in the number of Brønsted acid sites upon mild hydrothermal aging for Cu/SSZ-13 was not due to dealumination, but rather transformation of Cu sites, i.e., gradual conversion of ZCuOH (Cu2+ singly coordinated with Zeolite) to Z2Cu (Cu2+ doubly coordinated with Zeolite). This transformation was responsible for the increased low-temperature desorption peak in NH3-TPD since each ZCuOH adsorbed ~1 NH3 molecule while each Z2Cu adsorbed ~2 NH3 molecules under the conditions used here. These findings were used in Part II of this series of studies to develop a method for quantifying hydrothermal ageing of industrial Cu/SSZ-13 SCR catalysts. Authors would like to thank Randall Jines for his help with collecting the reactor data, Nancy W. Washton for measuring the NMR data and Tamas Varga for in-situ XRD measurements

  18. Tunable bandgap in hybrid perovskite CH3NH3Pb(Br3−yXy single crystals and photodetector applications

    Directory of Open Access Journals (Sweden)

    L. Wang

    2016-04-01

    Full Text Available We report the synthesis of CH3NH3Pb(Br3−yXy (X=Cl and I single crystals via a stepwise temperature control approach. High-quality CH3NH3Pb(Br3−yXy crystals with a tunable bandgap from 1.92eV to 2.53eV have been prepared successfully in this way. And further experiments revealed the influence of halogen content and preparation temperature on the structural and optical properties of these crystals. It is observed that chlorine can lower the critical nucleation energy, which results in crystallizing at lower temperature with the chlorine content increasing, while the nucleation energy increases slowly with increasing iodine content. Moreover, in contrast to Frank–van der Merwe growth with low heating rate, high heating rate leads to a mass of small size single crystals and Stranski-Krastanov growth. The single crystals with tunable band gap and impressive characteristics enable us to fabricate high performance photodetectors for different wavelengths.

  19. Plant communication: mediated by individual or blended VOCs?

    Science.gov (United States)

    Ueda, Hirokazu; Kikuta, Yukio; Matsuda, Kazuhiko

    2012-02-01

    Plants emit volatile organic compounds (VOCs) as a means to warn other plants of impending danger. Nearby plants exposed to the induced VOCs prepare their own defense weapons in response. Accumulated data supports this assertion, yet much of the evidence has been obtained in laboratories under artificial conditions where, for example, a single VOC might be applied at a concentration that plants do not actually experience in nature. Experiments conducted outdoors suggest that communication occurs only within a limited distance from the damaged plants. Thus, the question remains as to whether VOCs work as a single component or a specific blend, and at which concentrations VOCs elicit insect and pathogen defenses in undamaged plants. We discuss these issues based on available literature and our recent work, and propose future directions in this field.

  20. The influence of the relative thermal expansion and electric permittivity on phase transitions in the perovskite-type bidimensional layered NH3(CH2)3NH3CdBr4 compound

    Science.gov (United States)

    Staśkiewicz, Beata; Staśkiewicz, Anna

    2017-07-01

    Hydrothermal method has been used to synthesized the layered hybrid compound NH3(CH2)3NH3CdBr4 of perovskite architecture. Structural, dielectric and dilatometric properties of the compound have been analyzed. Negative thermal expansion (NTE) effect in the direction perpendicular to the perovskite plane as well as an unusual phase sequence have been reported based on X-ray diffraction analysis. Electric permittivity measurements evidenced the phase transitions at Tc1=326/328 K and Tc2=368/369 K. Relative linear expansion measurements almost confirmed these temperatures of phase transitions. Anomalies of electric permittivity and expansion behavior connected with the phase transitions are detected at practically the same temperatures as those observed earlier in differential scanning calorimetry (DSC), infrared (IR), far infrared (FIR) and Raman spectroscopy studies. Mechanism of the phase transitions is explained. Relative linear expansion study was prototype to estimate critical exponent value β for continuous phase transition at Tc1. It has been inferred that there is a strong interplay between the distortion of the inorganic network, those hydrogen bonds and the intermolecular interactions of the organic component.

  1. Rapid detection of pathogenic bacteria by volatile organic compound (VOC) analysis

    Science.gov (United States)

    Senecal, Andre G.; Magnone, Joshua; Yeomans, Walter; Powers, Edmund M.

    2002-02-01

    Developments in rapid detection technologies have made countless improvements over the years. However, because of the limited sample that these technologies can process in a single run, the chance of capturing and identifying a small amount of pathogens is difficult. The problem is further magnified by the natural random distribution of pathogens in foods. Methods to simplify pathogenic detection through the identification of bacteria specific VOC were studied. E. coli O157:H7 and Salmonella typhimurium were grown on selected agar medium to model protein, and carbohydrate based foods. Pathogenic and common spoilage bacteria (Pseudomonas and Morexella) were screened for unique VOC production. Bacteria were grown on agar slants in closed vials. Headspace sampling was performed at intervals up to 24 hours using Solid Phase Micro-Extraction (SPME) techniques followed by GC/MS analysis. Development of unique volatiles was followed to establish sensitivity of detection. E. coli produced VOC not found in either Trypticase Soy Yeast (TSY) agar blanks or spoilage organism samples were - indole, 1-decanol, and 2-nonanone. Salmonella specific VOC grown on TSY were 3-methyl-1-butanol, dimethyl sulfide, 2-undecanol, 2-pentadecanol and 1-octanol. Trials on potato dextrose agar (PDA) slants indicated VOC specific for E. coli and Salmonella when compared to PDA blanks and Pseudomonas samples. However, these VOC peaks were similar for both pathogens. Morexella did not grow on PDA slants. Work will continue with model growth mediums at various temperatures, and mixed flora inoculums. As well as, VOC production based on the dynamics of bacterial growth.

  2. Assessment of Exposure to VOCs among Pregnant Women in the National Children’s Study

    Directory of Open Access Journals (Sweden)

    Elizabeth Barksdale Boyle

    2016-03-01

    Full Text Available Epidemiologic studies can measure exposure to volatile organic compounds (VOCs using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children’s Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS. We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking and by observations by a trained data collector (presence of scented products in homes. We found several significant (p < 0.01 relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite

  3. Assessment of Exposure to VOCs among Pregnant Women in the National Children’s Study

    Science.gov (United States)

    Boyle, Elizabeth Barksdale; Viet, Susan M.; Wright, David J.; Merrill, Lori S.; Alwis, K. Udeni; Blount, Benjamin C.; Mortensen, Mary E.; Moye, John; Dellarco, Michael

    2016-01-01

    Epidemiologic studies can measure exposure to volatile organic compounds (VOCs) using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children’s Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS). We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking) and by observations by a trained data collector (presence of scented products in homes). We found several significant (p < 0.01) relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite N

  4. 41 CFR 102-118.195 - What documents must a transportation service provider (TSP) send to receive payment for a...

    Science.gov (United States)

    2010-07-01

    ... transportation service provider (TSP) send to receive payment for a transportation billing? 102-118.195 Section... must a transportation service provider (TSP) send to receive payment for a transportation billing? For... Government Billing Documents Terms and Conditions Governing Acceptance and Use of A Government Bill of Lading...

  5. Na+/H+ and Na+/NH4+ exchange activities of zebrafish NHE3b expressed in Xenopus oocytes

    Science.gov (United States)

    Ito, Yusuke; Kato, Akira; Hirata, Taku; Hirose, Shigehisa

    2014-01-01

    Zebrafish Na+/H+ exchanger 3b (zNHE3b) is highly expressed in the apical membrane of ionocytes where Na+ is absorbed from ion-poor fresh water against a concentration gradient. Much in vivo data indicated that zNHE3b is involved in Na+ absorption but not leakage. However, zNHE3b-mediated Na+ absorption has not been thermodynamically explained, and zNHE3b activity has not been measured. To address this issue, we overexpressed zNHE3b in Xenopus oocytes and characterized its activity by electrophysiology. Exposure of zNHE3b oocytes to Na+-free media resulted in significant decrease in intracellular pH (pHi) and intracellular Na+ activity (aNai). aNai increased significantly when the cytoplasm was acidified by media containing CO2-HCO3− or butyrate. Activity of zNHE3b was inhibited by amiloride or 5-ethylisopropyl amiloride (EIPA). Although the activity was accompanied by a large hyperpolarization of ∼50 mV, voltage-clamp experiments showed that Na+/H+ exchange activity of zNHE3b is electroneutral. Exposure of zNHE3b oocytes to medium containing NH3/NH4+ resulted in significant decreases in pHi and aNai and significant increase in intracellular NH4+ activity, indicating that zNHE3b mediates the Na+/NH4+ exchange. In low-Na+ (0.5 mM) media, zNHE3b oocytes maintained aNai of 1.3 mM, and Na+-influx was observed when pHi was decreased by media containing CO2-HCO3− or butyrate. These results provide thermodynamic evidence that zNHE3b mediates Na+ absorption from ion-poor fresh water by its Na+/H+ and Na+/NH4+ exchange activities. PMID:24401990

  6. B40 fullerene as a highly sensitive molecular device for NH3 detection at low bias: a first-principles study

    International Nuclear Information System (INIS)

    Lin, Bin; Dong, Huilong; Du, Chunmiao; Hou, Tingjun; Lin, Haiping; Li, Youyong

    2016-01-01

    The adsorption of small molecules (NH 3 , N 2 , H 2 and CH 4 ) on all-boron fullerene B 40 is investigated by density functional theory (DFT) and the non-equilibrium Green’s function (NEGF) for its potential application in the field of single-molecular gas sensors. The high adsorption energies (−1.09 to −0.75 eV) of NH 3 on different adsorption sites of the B 40 surface indicate that NH 3 strongly chemisorbs to B 40 . The charge transfer induced by the NH 3 adsorption results in a modification of the density of states (DOS) of B 40 near the Fermi level, and therefore changes its electronic transport properties. For all possible adsorption sites, the adsorption of NH 3 exclusively leads to a decrease of the conductance of B 40 . Taking into consideration that the non-polar gas molecules (e.g. N 2 , H 2 and CH 4 ) are only physisorbed and show negligible effect on the conductance properties of B 40 , we would expect that B 40 can be used as a single-molecular gas sensor to distinguish NH 3 from non-polar gas molecules at low bias. (paper)

  7. Reduced loss of NH 3 by coating urea with biodegradable polymers ...

    African Journals Online (AJOL)

    In agricultural lands, the loss of NH3 from surface-applied urea and micronutrient deficiencies are the two most common problems, which can be solved by using coated urea with micronutrients and biodegradable natural materials. These coatings can improve the nutrient status in the soil and simultaneously reduce ...

  8. A study of proton polarization in ammonia (NH sub 3 ) under irradiation and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, A.A.; Get' man, V.A.; Dzyubak, A.P.; Karnaukhov, I.M.; Lukhanin, A.A.; Neffa, A.Yu.; Semisalov, I.L.; Sorokin, P.V.; Sporov, E.S.; Telegin, Yu.N.; Tolmachev, I.A.; Trotsenko, V.I. (Kharkov Institute of Physics and Technology, Ukrainian SSR, Academy of Sciences, 310108 Kharkov, USSR (UA))

    1989-05-05

    The proton polarization in irradiated NH{sub 3} has been measured as a function of the irradiation dose and annealing temperature. The analysis of the experimental data obtained shows that under low-temperature'' irradiation along with the NH{sup {minus}}{sub 2} the e{sub tr}-radical is likely to be formed which contributes to the polarization build-up and relaxation and influences the radiation damage resistance of the target.

  9. Building materials. VOC emissions, diffusion behaviour and implications from their use

    International Nuclear Information System (INIS)

    Katsoyiannis, Athanasios; Leva, Paolo; Barrero-Moreno, Josefa; Kotzias, Dimitrios

    2012-01-01

    Five cement- and five lime-based building materials were examined in an environmental chamber for their emissions of Volatile Organic Compounds (VOCs). Typical VOCs were below detection limits, whereas not routinely analysed VOCs, like neopentyl glycol (NPG), dominated the cement-based products emissions, where, after 72 h, it was found to occur, in levels as high as 1400 μg m −3 , accounting for up to 93% of total VOCs. The concentrations of NPG were not considerably changed between the 24 and 72 h of sampling. The permeability of building materials was assessed through experiments with a dual environmental chamber; it was shown that building materials facilitate the diffusion of chemicals through their pores, reaching equilibrium relatively fast (6 h). - Highlights: ► Neopentyl glycol is reported in emissions from building materials for the first time. ► Neopentyl glycol dominates the VOC emissions from cement-based building materials. ► A dual chamber was developed to control diffusion through building materials. ► Building materials facilitate diffusion of indoor air pollutants through their pores. - Neopentyl glycol was detected in high concentrations in emissions from building materials.

  10. Solid phase microextraction: measurement of volatile organic compounds (VOCs) in Dhaka City air pollution.

    Science.gov (United States)

    Hussam, A; Alauddin, M; Khan, A H; Chowdhury, D; Bibi, H; Bhattacharjee, M; Sultana, S

    2002-08-01

    A solid phase microextraction (SPME) technique was applied for the sampling of volatile organic compounds (VOCs) in ambient air polluted by two stroke autorickshaw engines and automobile exhausts in Dhaka city, Bangladesh. Analysis was carried out by capillary gas chromatography (GC) and GC-mass spectrometry (MS). The methodology was tested by insitu sampling of an aromatic hydrocarbon mixture gas standard with a precision of +/-5% and an average accuracy of 1-20%. The accuracy for total VOCs concentration measurement was about 7%. VOC's in ambient air were collected by exposing the SPME fiber at four locations in Dhaka city. The chromatograms showed signature similar to that of unburned gasoline (petrol) and weathered diesel containing more than 200 organic compounds; some of these compounds were positively identified. These are normal hydrocarbons pentane (n-C5H2) through nonacosane (n-C29H60), aromatic hydrocarbons: benzene, toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, 1,3,5-trimethylbenzene, xylenes, and 1-isocyanato-3-methoxybenzene. Two samples collected near an autorickshaw station contained 783000 and 1479000 microg/m3 of VOCs. In particular, the concentration of toluene was 50-100 times higher than the threshold limiting value of 2000 microg/m3. Two other samples collected on street median showed 135000 microg/m3 and 180000 microg/m3 of total VOCs. The method detection limit of the technique for most semi-volatile organic compounds was 1 microg/m3.

  11. Crystal structure of (NH4)2[Fe(II) 5(HPO3)6], a new open-framework phosphite.

    Science.gov (United States)

    Berrocal, Teresa; Mesa, Jose Luis; Larrea, Edurne; Arrieta, Juan Manuel

    2014-11-01

    Di-ammonium hexa-phosphito-penta-ferrate(II), (NH4)2[Fe5(HPO3)6], was synthesized under mild hydro-thermal conditions and autogeneous pressure, yielding twinned crystals. The crystal structure exhibits an [Fe(II) 5(HPO3)6](2-) open framework with NH4 (+) groups as counter-cations. The anionic skeleton is based on (001) sheets of [FeO6] octa-hedra (one with point-group symmetry 3.. and one with .2.) linked along [001] through [HPO3](2-) oxoanions. Each sheet is constructed from 12-membered rings of edge-sharing [FeO6] octa-hedra, giving rise to channels with a radius of ca 3.1 Å in which the disordered NH4 (+) cations are located. The IR spectrum shows vibrational bands typical for phosphite and ammonium groups.

  12. Photocatalysts: ambient temperature destruction of VOCs

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R [IT Corp., Oak Ridge, TN (United States)

    1994-12-31

    Photocatalysis was a failure as a solar energy driven organic synthesis technique, but as this study indicates, it has undergone a renaissance as a promising treatment method for volatile organic compounds (VOCs) in air streams. Photocatalytic oxidation (PCO) relies upon the ability of certain semiconductors to be stimulated by UV radiation. UV light excites valence band electrons in the semiconductor catalyst to jump to a conductance band leaving holes in the valence band. The electrons and holes can react with compounds such as organic contaminants present in an air stream. Hallmarks of the technology include rapid destruction kinetics for many VOCs at ambient temperature and efficient use energy in the form of UV-A photons. Studies clearly indicate that PCO is competitive on capital cost and offers significant operating cost savings on selected applications. 6 refs., 3 tabs., 2 figs.

  13. Photocatalysts: ambient temperature destruction of VOCs

    International Nuclear Information System (INIS)

    Miller, R.

    1994-01-01

    Photocatalysis was a failure as a solar energy driven organic synthesis technique, but as this study indicates, it has undergone a renaissance as a promising treatment method for volatile organic compounds (VOCs) in air streams. Photocatalytic oxidation (PCO) relies upon the ability of certain semiconductors to be stimulated by UV radiation. UV light excites valence band electrons in the semiconductor catalyst to jump to a conductance band leaving holes in the valence band. The electrons and holes can react with compounds such as organic contaminants present in an air stream. Hallmarks of the technology include rapid destruction kinetics for many VOCs at ambient temperature and efficient use energy in the form of UV-A photons. Studies clearly indicate that PCO is competitive on capital cost and offers significant operating cost savings on selected applications. 6 refs., 3 tabs., 2 figs

  14. Solution Structure, Membrane Interactions, and Protein Binding Partners of the Tetraspanin Sm-TSP-2, a Vaccine Antigen from the Human Blood Fluke Schistosoma mansoni*

    Science.gov (United States)

    Jia, Xinying; Schulte, Leigh; Loukas, Alex; Pickering, Darren; Pearson, Mark; Mobli, Mehdi; Jones, Alun; Rosengren, Karl J.; Daly, Norelle L.; Gobert, Geoffrey N.; Jones, Malcolm K.; Craik, David J.; Mulvenna, Jason

    2014-01-01

    The tetraspanins (TSPs) are a family of integral membrane proteins that are ubiquitously expressed at the surface of eukaryotic cells. TSPs mediate a range of processes at the surface of the plasma membrane by providing a scaffold for the assembly of protein complexes known as tetraspanin-enriched microdomains (TEMs). We report here the structure of the surface-exposed EC2 domain from Sm-TSP-2, a TSP from Schistosoma mansoni and one of the better prospects for the development of a vaccine against schistosomiasis. This is the first solution structure of this domain, and our investigations of its interactions with lipid micelles provide a general model for interactions between TSPs, membranes, and other proteins. Using chemical cross-linking, eight potential protein constituents of Sm-TSP-2-mediated TEMs were also identified. These include proteins important for membrane maintenance and repair, providing further evidence for the functional role of Sm-TSP-2- and Sm-TSP-2-mediated TEMs. The identification of calpain, Sm29, and fructose-bisphosphate aldolase, themselves potential vaccine antigens, suggests that the Sm-TSP-2-mediated TEMs could be disrupted via multiple targets. The identification of further Sm-TSP-2-mediated TEM proteins increases the available candidates for multiplex vaccines and/or novel drugs targeting TEMs in the schistosome tegument. PMID:24429291

  15. Solution structure, membrane interactions, and protein binding partners of the tetraspanin Sm-TSP-2, a vaccine antigen from the human blood fluke Schistosoma mansoni.

    Science.gov (United States)

    Jia, Xinying; Schulte, Leigh; Loukas, Alex; Pickering, Darren; Pearson, Mark; Mobli, Mehdi; Jones, Alun; Rosengren, Karl J; Daly, Norelle L; Gobert, Geoffrey N; Jones, Malcolm K; Craik, David J; Mulvenna, Jason

    2014-03-07

    The tetraspanins (TSPs) are a family of integral membrane proteins that are ubiquitously expressed at the surface of eukaryotic cells. TSPs mediate a range of processes at the surface of the plasma membrane by providing a scaffold for the assembly of protein complexes known as tetraspanin-enriched microdomains (TEMs). We report here the structure of the surface-exposed EC2 domain from Sm-TSP-2, a TSP from Schistosoma mansoni and one of the better prospects for the development of a vaccine against schistosomiasis. This is the first solution structure of this domain, and our investigations of its interactions with lipid micelles provide a general model for interactions between TSPs, membranes, and other proteins. Using chemical cross-linking, eight potential protein constituents of Sm-TSP-2-mediated TEMs were also identified. These include proteins important for membrane maintenance and repair, providing further evidence for the functional role of Sm-TSP-2- and Sm-TSP-2-mediated TEMs. The identification of calpain, Sm29, and fructose-bisphosphate aldolase, themselves potential vaccine antigens, suggests that the Sm-TSP-2-mediated TEMs could be disrupted via multiple targets. The identification of further Sm-TSP-2-mediated TEM proteins increases the available candidates for multiplex vaccines and/or novel drugs targeting TEMs in the schistosome tegument.

  16. Detection of the HC3NH+ and HCNH+ ions in the L1544 pre-stellar core

    Science.gov (United States)

    Quénard, D.; Vastel, C.; Ceccarelli, C.; Hily-Blant, P.; Lefloch, B.; Bachiller, R.

    2017-09-01

    The L1544 pre-stellar core was observed as part of the ASAI (Astrochemical Surveys At IRAM) Large Program. We report the first detection in a pre-stellar core of the HCNH+ and HC3NH+ ions. The high spectral resolution of the observations allows us to resolve the hyperfine structure of HCNH+. Local thermodynamic equilibrium (LTE) analysis leads to derive a column density equal to (2.0 ± 0.2) × 1013 cm-2 for HCNH+ and (1.5 ± 0.5) × 1011 cm-2 for HC3NH+. We also present non-LTE analysis of five transitions of HC3N, three transitions of H13CN and one transition of HN13C, all of them linked to the chemistry of HCNH+ and HC3NH+. We computed for HC3N, HCN and HNC a column density of (2.0 ± 0.4) × 1013 cm-2, (3.6 ± 0.9) × 1014 cm-2 and (3.0 ± 1.0) × 1014 cm-2, respectively. We used the gas-grain chemical code nautilus to predict the abundances of all these species across the pre-stellar core. Comparison of the observations with the model predictions suggests that the emission from HCNH+ and HC3NH+ originates in the external layer where non-thermal desorption of other species was previously observed. The observed abundance of both ionic species ([HCNH+] ≃ 3 × 10-10 and [HC3NH+] ≃ [1.5 - 3.0] × 10-12, with respect to H2) cannot be reproduced at the same time by the chemical modelling within the error bars of the observations only. We discuss the possible reasons for the discrepancy and suggest that the current chemical models are not fully accurate or complete. However, the modelled abundances are within a factor of 3, consistent with the observations, considering a late stage of the evolution of the pre-stellar core, compatible with previous observations.

  17. Photoacoustic detection of NH3 in power plant emissions

    International Nuclear Information System (INIS)

    Rassmussen, O.

    1991-01-01

    The paper describes a photoacoustic spectrometer initially designed for detection of NH 3 in power plant emission with a detection limit below 1 ppm. The radiation source is a high tunable CO 2 waveguide laser emitting its own frequency standard in one of 90 laserlines. The detection is performed at reduced pressure where the vibration-rotation transitions give an unambiguous fingerprint for each trace gas. Immunity against interference is ensured by recording this characteristic spectral fingerprint over the tuning range of the laser, and problems associated with the high concentration of CO 2 or other interfering molecules are further eliminated by utilizing the effect of kinetic cooling in the photoacoustic phase. The use of a CO 2 laser as radiation source combined with the highly sensitive photoacoustic detection provides a great possibility of measuring a wide range of air pollutants in the range down to ppt concentrations. Experimental measurements have been carried out on gases like sulfur dioxide, ethylene, sulfur hexafluoride, vinylchloride, ozone, etc., and many others have been theoretically examined to give a high response in the CO 2 laser frequency range. A computerized NH 3 spectrometer has been constructed and tested under realistic conditions at a Danish power plant operating a test facility for selective non-catalytic reduction of NO x . Results of this test will be presented

  18. X-ray and NQR studies of bromoindate(III) complexes. [C{sub 2}H{sub 5}NH{sub 3}]{sub 4}InBr{sub 7}, [C(NH{sub 2}){sub 3}]{sub 3}InBr{sub 6}, and [H{sub 3}NCH{sub 2}C(CH{sub 3}){sub 2}CH{sub 2}NH{sub 3}]InBr{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Iwakiri, Takeharu; Ishihara, Hideta [Saga Univ. (Japan). Faculty of Culture and Education; Terao, Hiromitsu [Tokushima Univ. (Japan). Faculty of Integrated Arts and Sciences; Lork, Enno; Gesing, Thorsten M. [Bremen Univ. (Germany). Inst. of Inorganic Chemistry and Crystallography

    2017-03-01

    The crystal structures of [C{sub 2}H{sub 5}NH{sub 3}]{sub 4}InBr{sub 7}(1), [C(NH{sub 2}){sub 3}]{sub 3}InBr{sub 6}(2), and [H{sub 3}NCH{sub 2}C(CH{sub 3}){sub 2}CH{sub 2}NH{sub 3}]InBr{sub 5}(3) were determined at 100(2) K: monoclinic, P2{sub 1}/n, a=1061.94(3), b=1186.40(4), c=2007.88(7) pm, β= 104.575(1) , Z=4 for 1; monoclinic, C2/c, a=3128.81(12), b=878.42(3), c=2816.50(10) pm, β=92.1320(10) , Z=16 for 2; orthorhombic, P2{sub 1}2{sub 1}2{sub 1}, a=1250.33(5), b=1391.46(6), c=2503.22(9) pm, Z=4 for 3. The structure of 1 contains an isolated octahedral [InBr{sub 6}]{sup 3-} ion and a Br{sup -} ion. The structure of 2 contains three different isolated octahedral [InBr{sub 6}]{sup 3-} ions. The structure of 3 has a corner-shared double-octahedral [In{sub 2}Br{sub 11}]{sup 5-} ion and an isolated tetrahedral [InBr{sub 4}]{sup -} ion. The {sup 81}Br nuclear quadrupole resonance (NQR) lines of the terminal Br atoms of the compounds are widely spread in frequency, and some of them show unusual positive temperature dependence. These observations manifest the N-H..Br-In hydrogen bond networks developed between the cations and anions to stabilize the crystal structures. The {sup 81}Br NQR and differential thermal analysis (DTA) measurements have revealed the occurrence of unique phase transitions in 1 and 3. When the bond angles were estimated from the electric field gradient (EFG) directions calculated by the molecular orbital (MO) methods, accurate values were obtained for [InBr{sub 6}]{sup 3-} of 1 and for [In{sub 2}Br{sub 11}]{sup 5-} and [InBr{sub 4}]{sup -} of 3, except for several exceptions in those for the latter two ions. On the other hand, the calculations of {sup 81}Br NQR frequencies have produced up to 1.4 times higher values than the observed ones.

  19. Enhancement of NH3 Gas Sensitivity at Room Temperature by Carbon Nanotube-Based Sensor Coated with Co Nanoparticles

    Directory of Open Access Journals (Sweden)

    Lich Quang Nguyen

    2013-01-01

    Full Text Available Multi-walled carbon nanotube (MWCNT film has been fabricated onto Pt-patterned alumina substrates using the chemical vapor deposition method for NH3 gas sensing applications. The MWCNT-based sensor is sensitive to NH3 gas at room temperature. Nanoclusters of Co catalysts have been sputtered on the surface of the MWCNT film to enhance gas sensitivity with respect to unfunctionalized CNT films. The gas sensitivity of Co-functionalized MWCNT-based gas sensors is thus significantly improved. The sensor exhibits good repeatability and high selectivity towards NH3, compared with alcohol and LPG.

  20. Theoretical study of the properties of BH3NH3

    International Nuclear Information System (INIS)

    Binkley, J.S.; Thorne, L.R.

    1983-01-01

    Borane monoammoniate (BH 3 NH 3 ) has been studied using several ab initio electronic structure methods and Gaussian basis sets. Equilibrium geometries have been computed at the Hartree--Fock level and, using the electron-correlated Moller--Plesset perturbation method, carried out to third order (MP3) with double-zeta polarized quality basis sets. The computed MP3 geometry is in close agreement with recent microwave data; electron correlation is found to be necessary for a proper description of the B--N distance. Hartree--Fock dipole moments and harmonic vibrational frequencies are presented and discussed. Moller--Plesset perturbation theory carried out to fourth order with triple-zeta plus polarization basis sets is used to compute a B--N dissociation energy of 34.7 kcal mol -1 and a (Hartree--Fock zero-point corrected) rotational barrier of 2.065 kcal mol -1 , which is in excellent agreement with the experimental value. Analysis of the dissociation energy as a function of perturbation order indicates that terms involving triple and quadruple substitutions are required in the dissociation energy

  1. Improved Dehydrogenation Properties of 2LiNH2-MgH2 by Doping with Li3AlH6

    Directory of Open Access Journals (Sweden)

    Shujun Qiu

    2017-01-01

    Full Text Available Doping with additives in a Li-Mg-N-H system has been regarded as one of the most effective methods of improving hydrogen storage properties. In this paper, we prepared Li3AlH6 and evaluated its effect on the dehydrogenation properties of 2LiNH2-MgH2. Our studies show that doping with Li3AlH6 could effectively lower the dehydrogenation temperatures and increase the hydrogen content of 2LiNH2-MgH2. For example, 2LiNH2-MgH2-0.1Li3AlH6 can desorb 6.43 wt % of hydrogen upon heating to 300 °C, with the onset dehydrogenation temperature at 78 °C. Isothermal dehydrogenation testing indicated that 2LiNH2-MgH2-0.1Li3AlH6 had superior dehydrogenation kinetics at low temperature. Moreover, the release of byproduct NH3 was successfully suppressed. Measurement of the thermal diffusivity suggests that the enhanced dehydrogenation properties may be ascribed to the fact that doping with Li3AlH6 could improve the heat transfer for solid–solid reaction.

  2. The recombination mechanisms leading to amplified spontaneous emission at the true-green wavelength in CH3NH3PbBr3 perovskites

    KAUST Repository

    Priante, Davide; Dursun, Ibrahim; Alias, M. S.; Shi, Dong; Melnikov, V. A.; Ng, Tien Khee; Mohammed, Omar F.; Bakr, Osman; Ooi, Boon S.

    2015-01-01

    We investigated the mechanisms of radiative recombination in a CH3NH3PbBr3 hybrid perovskite material using low-temperature, power-dependent (77K), and temperature-dependent photoluminescence (PL) measurements. Two bound-excitonic radiative

  3. NORPERM, the Norwegian Permafrost Database - a TSP NORWAY IPY legacy

    Science.gov (United States)

    Juliussen, H.; Christiansen, H. H.; Strand, G. S.; Iversen, S.; Midttømme, K.; Rønning, J. S.

    2010-10-01

    NORPERM, the Norwegian Permafrost Database, was developed at the Geological Survey of Norway during the International Polar Year (IPY) 2007-2009 as the main data legacy of the IPY research project Permafrost Observatory Project: A Contribution to the Thermal State of Permafrost in Norway and Svalbard (TSP NORWAY). Its structural and technical design is described in this paper along with the ground temperature data infrastructure in Norway and Svalbard, focussing on the TSP NORWAY permafrost observatory installations in the North Scandinavian Permafrost Observatory and Nordenskiöld Land Permafrost Observatory, being the primary data providers of NORPERM. Further developments of the database, possibly towards a regional database for the Nordic area, are also discussed. The purpose of NORPERM is to store ground temperature data safely and in a standard format for use in future research. The IPY data policy of open, free, full and timely release of IPY data is followed, and the borehole metadata description follows the Global Terrestrial Network for Permafrost (GTN-P) standard. NORPERM is purely a temperature database, and the data is stored in a relation database management system and made publically available online through a map-based graphical user interface. The datasets include temperature time series from various depths in boreholes and from the air, snow cover, ground-surface or upper ground layer recorded by miniature temperature data-loggers, and temperature profiles with depth in boreholes obtained by occasional manual logging. All the temperature data from the TSP NORWAY research project is included in the database, totalling 32 temperature time series from boreholes, 98 time series of micrometeorological temperature conditions, and 6 temperature depth profiles obtained by manual logging in boreholes. The database content will gradually increase as data from previous and future projects are added. Links to near real-time permafrost temperatures, obtained

  4. Use of biofilters and suspended-growth reactors to treat VOC's

    Energy Technology Data Exchange (ETDEWEB)

    Neal, A.B.; Loehr, R.C.

    2000-07-01

    The greater limits placed on volatile organic compound (VOC) emissions by the Clean Air Act Amendments have stimulated evaluation of various VOC treatment methods. Two applicable gas phase treatment technologies are biofiltration and suspended growth reactors. Biofiltration removes contaminants from gas streams that are passed through a bed of biologically active solids. An aerobic suspended-growth reactor (SGR) removes VOCs by biologically treating contaminated air bubbled through an aqueous suspension of active microorganisms. This research compared the performance of a typical compost biofilter to a SGR for the removal of a common VOC (toluene) from gas streams. The objective was to evaluate the impact of mass loading on process performance. Major performance parameters investigated were (1) mass emitted and elimination capacity, (2) off-gas concentrations exiting each type of reactor for various mass loadings, and (3) removal efficiencies obtained by each type of reactor. The results indicated that SGRs can effectively treat gases containing VOCs. For mass loadings ranging from 5 to 30 mg/l-h, the biofilters and SGRs achieved similar VOC removals, in the range of 96--99.7%. Drying of the biofilter medium occurred a high mass loadings. In the SGRs, at mass loadings greater than 17 mg/l-h, process performance decreased when an unknown colored substance was present.

  5. Synthesis and crystal structure of triammine pentafluorido tantalum(V) [TaF{sub 5}(NH{sub 3}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Sebastian A.; Kraus, Florian [Department Chemie, Technische Universitaet Muenchen, Lichtenbergstrasse 4, 85747 Garching (Germany); Lozinsek, Matic [Department of Inorganic Chemistry and Technology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2013-07-01

    [Sr(HF){sub 3}(TaF{sub 6}){sub 2}] reacts with liquid ammonia under the formation of colorless crystals of triammine pentafluorido tantalum(V) [TaF{sub 5}(NH{sub 3}){sub 3}] (1). The structure was elucidated by low-temperature X-ray structure analysis. Compound 1 crystallizes in the monoclinic space group P2{sub 1}/c with a = 5.1525(6), b = 11.736(1), c = 10.171(1) Aa, β = 94.843(9) , V = 612.8(1) Aa{sup 3} at 123 K with Z = 4. Its structure displays discrete TaF{sub 5}(NH{sub 3}){sub 3} molecules, which are interconnected by N-H..F hydrogen bonds to form a complex three-dimensional network. The title compound is a rare example of a neutral, molecular, eight-coordinate tantalum species. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Analysis of the Effectiveness of the Retire Tool When Deciding Between High 36 Retirement and Blended TSP Retirement

    Science.gov (United States)

    2016-12-01

    22202-4302, and to the Office of Management and Budget , Paperwork Reduction Project (0704-0188) Washington DC 20503. 1. AGENCY USE ONLY (Leave...VALUE OF THE TSP ...........16 D. ELEMENTS OF RETIRE TOOL ANALYSIS .....................................18 1. Cash Flow Analysis...23 3. Cash Flow Comparison ...............................................................24 4. Volatility Analysis

  7. Dechlorination of PCBs, CAHs, herbicides and pesticides neat and in soils at 25 degrees C using Na/NH3.

    Science.gov (United States)

    Pittman, Charles U; He, Jinbao

    2002-05-03

    Na/NH3 reductions have been used to dehalogenate polychlorinated biphenyls (PCBs), chlorinated aliphatic hydrocarbons (CAHs) and pesticides at diffusion controlled rates at room temperature in model compound studies in both dry NH3 and when water was added. The rate ratio of dechlorination (aliphatic and aromatic compounds) versus reaction of the solvated electron with water is very large, allowing wet soils or sludges to be remediated without an unreasonable consumption of sodium. Several soils, purposely contaminated with 1,1,1-trichloroethane, 1-chlorooctane and tetrachloroethylene, were remediated by slurring the soils in NH3 followed by addition of sodium. The consumption of sodium per mole of chlorine removed was examined as a function of both the hazardous substrate's concentration in the soil and the amount of water present. The Na consumption per Cl removed increases as the amount of water increases and as the substrate concentration in soil decreases. However, remediation was still readily accomplished from 5000 to 3000ppm to sub ppm levels of RCl in the presence of substantial amounts of water. PCB- and dioxin-contaminated oils were remediated with Na/NH3 as were PCB-contaminated soils and sludges from contaminated sites. Ca/NH3 treatments also successfully remediated PCB-contaminated clay, sandy and organic soils but laboratory studies demonstrated that Ca was less efficient than Na when substantial amounts of water were present. The advantages of solvated electron reductions using Na/NH3 include: (1) very rapid dehalogenation rates at ambient temperature, (2) soils (even clay soils) break down into particles and slurry nicely in NH3, (3) liquid ammonia handling technology is well known and (4) removal from soils, recovery and recycle of ammonia is easy due to its low boiling point. Finally, dechlorination is extremely fast even for the 'corner' chlorines in the substrate Mirex (structure in Eq. (5)).

  8. Radio-Frequency-Based NH3-Selective Catalytic Reduction Catalyst Control: Studies on Temperature Dependency and Humidity Influences

    Directory of Open Access Journals (Sweden)

    Markus Dietrich

    2017-07-01

    Full Text Available The upcoming more stringent automotive emission legislations and current developments have promoted new technologies for more precise and reliable catalyst control. For this purpose, radio-frequency-based (RF catalyst state determination offers the only approach for directly measuring the NH3 loading on selective catalytic reduction (SCR catalysts and the state of other catalysts and filter systems. Recently, the ability of this technique to directly control the urea dosing on a current NH3 storing zeolite catalyst has been demonstrated on an engine dynamometer for the first time and this paper continues that work. Therefore, a well-known serial-type and zeolite-based SCR catalyst (Cu-SSZ-13 was investigated under deliberately chosen high space velocities. At first, the full functionality of the RF system with Cu-SSZ-13 as sample was tested successfully. By direct RF-based NH3 storage control, the influence of the storage degree on the catalyst performance, i.e., on NOx conversion and NH3 slip, was investigated in a temperature range between 250 and 400 °C. For each operation point, an ideal and a critical NH3 storage degree was found and analyzed in the whole temperature range. Based on the data of all experimental runs, temperature dependent calibration functions were developed as a basis for upcoming tests under transient conditions. Additionally, the influence of exhaust humidity was observed with special focus on cold start water and its effects to the RF signals.

  9. Radio-Frequency-Based NH3-Selective Catalytic Reduction Catalyst Control: Studies on Temperature Dependency and Humidity Influences

    Science.gov (United States)

    Dietrich, Markus; Hagen, Gunter; Reitmeier, Willibald; Burger, Katharina; Hien, Markus; Grass, Philippe; Kubinski, David; Visser, Jaco; Moos, Ralf

    2017-01-01

    The upcoming more stringent automotive emission legislations and current developments have promoted new technologies for more precise and reliable catalyst control. For this purpose, radio-frequency-based (RF) catalyst state determination offers the only approach for directly measuring the NH3 loading on selective catalytic reduction (SCR) catalysts and the state of other catalysts and filter systems. Recently, the ability of this technique to directly control the urea dosing on a current NH3 storing zeolite catalyst has been demonstrated on an engine dynamometer for the first time and this paper continues that work. Therefore, a well-known serial-type and zeolite-based SCR catalyst (Cu-SSZ-13) was investigated under deliberately chosen high space velocities. At first, the full functionality of the RF system with Cu-SSZ-13 as sample was tested successfully. By direct RF-based NH3 storage control, the influence of the storage degree on the catalyst performance, i.e., on NOx conversion and NH3 slip, was investigated in a temperature range between 250 and 400 °C. For each operation point, an ideal and a critical NH3 storage degree was found and analyzed in the whole temperature range. Based on the data of all experimental runs, temperature dependent calibration functions were developed as a basis for upcoming tests under transient conditions. Additionally, the influence of exhaust humidity was observed with special focus on cold start water and its effects to the RF signals. PMID:28704929

  10. Contrasting VOC Composition in London, UK and Beijing, China

    Science.gov (United States)

    Dunmore, R.; Hopkins, J. R.; Shaw, M.; Squires, F. A.; Lee, J. D.; Lewis, A. C.; Hamilton, J. F.

    2017-12-01

    With an increasing fraction of the world's population now living in megacities, urban air quality in those locations has the potential to be one of the largest controllable factors for public health. Both London and Beijing are classified as megacities, with the latter almost twice as densely populated. The key drivers and trajectory of air pollution are unique to each location; London has substantially reduced PM10 concentrations over the past two decades but continues to have high urban NO2. Beijing has had well-reported high levels of PM, is now in a phase of gradual decline, and has proportionately low NO2. Both locations however, continue to emit a mix of gas phase pollutants with the potential to form photochemical ozone. Whilst the abundance of NOx in each city is relatively straightforward to quantify, the VOC mixtures that are present differ between these two cities and this has consequential impacts on the downwind ozone formation potential. This work reports a comprehensive assessment of VOC speciation, reactivity and abundance in the two cities using a common set of inter-comparable measurement approaches. Hourly observations of VOCs over the range C2 - C13+ were made using two gas chromatography (GC) instruments; a PLOT column based GC for the most volatile fraction (C2-C7) and a comprehensive two-dimensional GC (GCxGC) for VOCs with more than 7 carbons. London has atmospheric VOC concentrations that in mass and reactivity terms are dominated by longer chain VOCs from diesel fuel. The VOC mixture in ambient Beijing air is dominated by short chain VOCs, a mix of both alkenes from incomplete combustion sources and alkanes and aromatics from petrochemical sources. The substantial difference in the fleet proportions of gasoline and diesel powered vehicles between the two cities is clearly reflected in ambient VOCs. In summertime, isoprene was a notable contributor to VOC reactivity in both cities despite both being highly urbanised locations. The absolute

  11. Comparative study of wheat utilization of NH4 and NO3 as sources of N-fertilizer using N15 technique

    International Nuclear Information System (INIS)

    Khalifa, Kh.

    1993-05-01

    Two field experiments were conducted separately on wheat (Cultivar ACSAD-65) in 1987/1988 at the Research Station of Arabic Center for the Studies of Arid Zones and Dry Lands (ACSAD) in Deir-Ezzor, Using N 15 methodology to compare the efficient utilization of N 15 -NO 3 and N 15 -N H 4 radicals as sources of nitrogen applied in three different levels (50, 100 and 200 Kg N/ha and two placement methods (Top-dressed and Side-dressed). The results indicate that Ndff % in the from of N 15 -NH 4 was higher than N 15 -NO 3 in both placements, at different growth stages, consequently, when using N-NH 4 form, N-uptake was higher than N-NO 3 form; the efficiency of N-NH 4 was higher than N-NO 3 in most cases regardless of the method of placement; the rate of applied nitrogen in both forms (N-NH 4 and N-NO 3 ) had higher effect on yield more than the placements; side-dressed placement had higher effect on the efficiency of the utilization of N-NO 3 and N-NH 4 as well as on crop yield than the Top-dressed; using N-NO 3 , A-values in the three growth stages of crop at the nitrogen levels used, were higher than using N-NH 4 in both placements; and finally using N-NO 3 in the second and third stages of crop growth, the yield was higher than using N-NH 4 and almost similar in the first stages. (author). 9 refs., 26 tabs

  12. Corrosion and solubility in a TSP-buffered chemical environment following a loss of coolant accident: Part 2 – Zinc

    International Nuclear Information System (INIS)

    Pease, David; LaBrier, Daniel; Ali, Amir; Blandford, Edward D.; Howe, Kerry J.

    2016-01-01

    Highlights: • Zinc release is limited to less than 1 mg/L in TSP-buffered solution under a variety of conditions (pH, temperature, zinc source). • Zinc release in high-temperature non-TSP-buffered environment is approximately 25 mg/L. • Long-term zinc release is controlled by passivation (without TSP) and zinc solubility (with TSP). • Precipitation and solubility of zinc phosphate limit the release of zinc. - Abstract: Bench experiments were conducted to investigate the effect of the presence of trisodium phosphate (TSP) on the corrosion and release of zinc from metallic zinc-bearing surfaces under conditions representative of the containment pool following a postulated loss of coolant accident (LOCA) at a nuclear power generating facility. The experiments showed that in non-buffered (acidic) environments, measurable quantities of zinc are released from zinc-bearing surfaces. Precipitation and solubility of phosphate-based corrosion products, such as zinc phosphate, limit the release of zinc from zinc-bearing surfaces. These experiments have found that under a variety of conditions, including variations of temperature, pH, and across different zinc-bearing surfaces, the release of zinc into solution is limited to <1 mg/L when phosphate is present. When phosphate is not present, zinc release is instead bounded by a markedly higher saturation limit which is a strong function of the solution temperature.

  13. Fourier transform infrared study of the phase transitions in (NH4)3VO2FO4

    Science.gov (United States)

    de Waal, D.; Heyns, A. M.

    1994-01-01

    Ammonium oxofluorovanadate compounds are known to show some potential as ferroelectric materials. The whole series of ammonium and sodium oxofluorovanadate compounds including Na3VO2F4 have already been prepared and investigated by means of various techniques including x-ray diffraction, EPR, and vibrational spectroscopy. It was established that the pure ammonium compound shows the two above mentioned transitions from phase A (below 200 K) to phase B (between 200 and 400 K) and phase C (above 400 K) while Na(NH4)2VO2F4 has only one transition from phase A to phase B around 400 K4. In the present study various aspects regarding the nature of the structures of (NH4)3VO2F3 and Na(NH4)2VO2F4 and its influence on the phase transitions have been investigated.

  14. The influence of NO3- and NH4+ on the sites of nitrogen assimilation of F1 hybrid cauliflower (Brassica oleracea. L. botrytis)

    International Nuclear Information System (INIS)

    Asiah Ahmad; Parsons, R.; Md Razi Ismail

    2002-01-01

    The sites of Nitrogen assimilation of Fl hybrid cauliflower (Brassica oleracea L.) grown in vermiculite: pearlite on either NO 3 or NH 4 nutrition was investigated using 15 N techniques. Labelling studies using 15 NO 3 Or 15 NH 4 alone to follow a time course of 15 NO 3 or 15 NH 4 incorporated into amino compounds in Fl hybrid cauliflower was conducted over periods of up to 24 hours. The 15 N enrichment of amino compounds in various plant parts was measured using GC-MS and isotopic abundance mass spectrometry techniques. In roots of 15 NH 4 -N fed plant, the 15 N label rapidly appears in glutamate at high enrichment within 30 minutes and increased substantially up to 6 hours after feeding. The labelled glutamate appears to decrease slowly after 6 hours. In leaves, the glutamate shows much lower labelling within 30 minutes than in the roots and became slowly enriched 6 hours after feeding. Labelled glutamate was only detected in the curd 6 hours later. This may indicate that in NH 4 -N fed plants, most NH 4 is assimilated in the roots and translocated as amino acids to the leaves and curd. In contrast to 15 NO 3 -N fed plant, both the roots and leaves showed significant label in glutamate within 30 minutes and subsequently increased in labelled enrichment over the time period of 6 hours. The leaves contained higher labelled glutamate than the roots. The labelled glutamate in the leaves decreased significantly at 24 hours after feeding. Label was incorporated in glutamate at low level in the curd after 2 hours and became highly enriched at 6 and 24 hours after feeding. Thus in NO 3 -N fed plants, NO 3 reduction and assimilation occurred both in root and leaf which mainly occur in the leaf. Therefore differences in the response of plant growth to NO3 - and NH 4 + nutrition observed in other studies could be due to the fact that NO 3 is primarily assimilated in the leaf whereas NH 4 is root based. No significant labelling was found in serine in both roots of 15 NH 4 -N

  15. Identification of forbidden vibration-rotation transitions in 15NH3

    Science.gov (United States)

    Urban, Š.; D'Cunha, Romola; Narahari Rao, K.

    1984-07-01

    Forbidden Δk - l = 3 vibration-rotation transitions have been observed in the ν4 band of 15NH3. The analysis of these transitions, together with previously published data on the allowed transitions, has made it possible to determine a set of molecular parameters, including for the first time the rotational constant C as well as the centrifugal distortion constants DK and HKKK, which are necessary for the calculation of energy levels. Some weak forbidden transitions in the ν2 band have also been observed.

  16. NH{sub 3} decomposition and simultaneous H{sub 2} separation with a commercial Pd-Cu-Ag/V membrane

    Energy Technology Data Exchange (ETDEWEB)

    Skodras, G.; Sakelleropoulos, G. [Centre for Research and Technology, Hellas, Ptolemaidas-Kozanis, Ptolemaida (Greece). Inst. for Solid Fuel Technolgy and Applications]|[Aristotle Univ. of Thessaloniki, Thessaloniki (Greece). Dept. of Chemical Engineering, Chemical Process Engineering Lab]|[Centre for Research and Technology, Hellas, Thermis, Thessaloniki (Greece). Chemical Process Research Inst.; Kaldis, S. [Centre for Research and Technology, Hellas, Thermis, Thessaloniki (Greece). Chemical Process Research Inst.; Topis, S. [Centre for Research and Technology, Hellas, Ptolemaidas-Kozanis, Ptolemaida (Greece). Inst. for Solid Fuel Technolgy and Applications]|[Aristotle Univ. of Thessaloniki, Thessaloniki (Greece). Dept. of Chemical Engineering, Chemical Process Engineering Lab; Koutsonikolas, D. [Aristotle Univ. of Thessaloniki, Thessaloniki (Greece). Dept. of Chemical Engineering, Chemical Process Engineering Lab; Grammelis, P. [Centre for Research and Technology, Hellas, Ptolemaidas-Kozanis, Ptolemaida (Greece). Inst. for Solid Fuel Technolgy and Applications

    2006-07-01

    The potential for integrated gasification combined cycle (IGCC) technology to emerge as an efficient and environmentally clean technology for power generation from coal gas was discussed. Ammonia (NH{sub 3}) is formed during gasification of coal. The concentration in coal gas depends on temperature, pressure, residence time and coal rank. In the gas turbine as much as 50 per cent of the NH{sub 3} in the fuel gas can be converted to NOx when the gas is combusted to produce power. A catalyst is required to bring NH{sub 3} levels down to acceptable levels for a gas turbine. This study examined the simultaneous ammonia (NH{sub 3}) decomposition and hydrogen (H{sub 2}) separation via a commercial Pd-Cu-Ag/V catalytic membrane reactor with 100 per cent H{sub 2} selectivity. A 16 per cent Ni/Al{sub 2}O{sub 3} catalyst was prepared and 88 per cent NH{sub 3} conversion was achieved with 20 per cent H{sub 2} in the feed stream. Increase of temperature and prolongation of residence time resulted in higher conversions. However, pressure increase lowered the decomposition due to the high H{sub 2} partial pressure. In order to develop kinetic equations, experiments at differential conversions were also performed. H{sub 2} diffusion was found to be the rate limiting step of H{sub 2} transport through the membrane. As such, H{sub 2} permeance increased exponentially with temperature. Mathematical model were then developed to describe the operation of the catalytic membrane reactor and to compare its performance with the conventional reactor. It was concluded that the conversion of NH{sub 3} can be increased significantly using the Pd-Cu-Ag/V membrane. 14 refs., 3 tabs., 7 figs.

  17. The effect of wet film thickness on VOC emissions from a finishing varnish.

    Science.gov (United States)

    Lee, Shun-Cheng; Kwok, Ngai-Hong; Guo, Hai; Hung, Wing-Tat

    2003-01-20

    Finishing varnishes, a typical type of oil-based varnishes, are widely used to shine metal, wood trim and cabinet surfaces in Hong Kong. The influence of wet film thickness on volatile organic compound (VOC) emissions from a finishing varnish was studied in an environmental test chamber. The varnish was applied on an aluminium foil with three different wet film thickness (35.2, 69.9 and 107.3 microm). The experimental conditions were 25.0 degrees C, 50.0% relative humidity (RH) with an air exchange rate of 0.5 h(-1). The concentrations of the major VOCs were monitored for the first 10 h. The air samples were collected by canisters and analysed by gas chromatography/mass selective detector (GC/MSD). Six major VOCs including toluene, chlorobenzene, ethylbenzene, m,p-xylene, o-xylene and 1,3,5-trimethylbenzene were identified and quantified. Marked differences were observed for three different film thicknesses. VOC concentrations increased rapidly during the first few hours and then decreased as the emission rates declined. The thicker the wet film, the higher the VOC emissions. A model expression included an exponentially decreasing emission rate of varnish film. The concentration and time data measured in the chamber were used to determine the parameters of empirical emission rate model. The present work confirmed that the film thickness of varnish influenced markedly the concentrations and emissions of VOCs. Copyright 2002 Elsevier Science B.V.

  18. 41 CFR 102-118.260 - Must my agency send all quotations, tenders, or contracts with a TSP to GSA?

    Science.gov (United States)

    2010-07-01

    ... quotations, tenders, or contracts with a TSP to GSA? 102-118.260 Section 102-118.260 Public Contracts and... REGULATION TRANSPORTATION 118-TRANSPORTATION PAYMENT AND AUDIT Use of Government Billing Documents Quotations, Tenders Or Contracts § 102-118.260 Must my agency send all quotations, tenders, or contracts with a TSP to...

  19. Wide range tuning of the size and emission color of CH3NH3PbBr3 quantum dots by surface ligands

    Directory of Open Access Journals (Sweden)

    Xin Fang

    2017-08-01

    Full Text Available Organic-inorganic halide perovskite CH3NH3PbX3 (X= I, Br, Cl quantum dots (QDs possess the characters of easy solution-process, high luminescence yield, and unique size-dependent optical properties. In this work, we have improved the nonaqueous emulsion method to synthesize halide perovskite CH3NH3PbBr3 QDs with tunable sizes. Their sizes have been tailored from 5.29 to 2.81 nm in diameter simply by varying the additive amount of surfactant, n-octylamine from 5 to 120 μL. Correspondingly, the photoluminescence (PL peaks shift markedly from 520 nm to very deep blue, 436 nm due to quantum confinement effect. The PL quantum yields exceed 90% except for the smallest QDs. These high-quality QDs have potential to build high-performance optoelectronic devices.

  20. The recombination mechanisms leading to amplified spontaneous emission at the true-green wavelength in CH3NH3PbBr3 perovskites

    Science.gov (United States)

    Priante, D.; Dursun, I.; Alias, M. S.; Shi, D.; Melnikov, V. A.; Ng, T. K.; Mohammed, O. F.; Bakr, O. M.; Ooi, B. S.

    2015-02-01

    We investigated the mechanisms of radiative recombination in a CH3NH3PbBr3 hybrid perovskite material using low-temperature, power-dependent (77 K), and temperature-dependent photoluminescence (PL) measurements. Two bound-excitonic radiative transitions related to grain size inhomogeneity were identified. Both transitions led to PL spectra broadening as a result of concurrent blue and red shifts of these excitonic peaks. The red-shifted bound-excitonic peak dominated at high PL excitation led to a true-green wavelength of 553 nm for CH3NH3PbBr3 powders that are encapsulated in polydimethylsiloxane. Amplified spontaneous emission was eventually achieved for an excitation threshold energy of approximately 350 μJ/cm2. Our results provide a platform for potential extension towards a true-green light-emitting device for solid-state lighting and display applications.

  1. The recombination mechanisms leading to amplified spontaneous emission at the true-green wavelength in CH3NH3PbBr3 perovskites

    KAUST Repository

    Priante, Davide

    2015-02-23

    We investigated the mechanisms of radiative recombination in a CH3NH3PbBr3 hybrid perovskite material using low-temperature, power-dependent (77K), and temperature-dependent photoluminescence (PL) measurements. Two bound-excitonic radiative transitions related to grain size inhomogeneity were identified. Both transitions led to PL spectra broadening as a result of concurrent blue and red shifts of these excitonic peaks. The red-shifted bound-excitonic peak dominated at high PL excitation led to a true-green wavelength of 553nm for CH3NH3PbBr3 powders that are encapsulated in polydimethylsiloxane. Amplified spontaneous emission was eventually achieved for an excitation threshold energy of approximately 350μJ/cm2. Our results provide a platform for potential extension towards a true-green light-emitting device for solid-state lighting and display applications.

  2. Monitoring of volatile organic compounds (VOCs) from an oil and gas station in northwest China for 1 year

    Science.gov (United States)

    Zheng, Huang; Kong, Shaofei; Xing, Xinli; Mao, Yao; Hu, Tianpeng; Ding, Yang; Li, Gang; Liu, Dantong; Li, Shuanglin; Qi, Shihua

    2018-04-01

    Oil and natural gas are important for energy supply around the world. The exploring, drilling, transportation and processing in oil and gas regions can release a lot of volatile organic compounds (VOCs). To understand the VOC levels, compositions and sources in such regions, an oil and gas station in northwest China was chosen as the research site and 57 VOCs designated as the photochemical precursors were continuously measured for an entire year (September 2014-August 2015) using an online monitoring system. The average concentration of total VOCs was 297 ± 372 ppbv and the main contributor was alkanes, accounting for 87.5 % of the total VOCs. According to the propylene-equivalent concentration and maximum incremental reactivity methods, alkanes were identified as the most important VOC groups for the ozone formation potential. Positive matrix factorization (PMF) analysis showed that the annual average contributions from natural gas, fuel evaporation, combustion sources, oil refining processes and asphalt (anthropogenic and natural sources) to the total VOCs were 62.6 ± 3.04, 21.5 ± .99, 10.9 ± 1.57, 3.8 ± 0.50 and 1.3 ± 0.69 %, respectively. The five identified VOC sources exhibited various diurnal patterns due to their different emission patterns and the impact of meteorological parameters. Potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models based on backward trajectory analysis indicated that the five identified sources had similar geographic origins. Raster analysis based on CWT analysis indicated that the local emissions contributed 48.4-74.6 % to the total VOCs. Based on the high-resolution observation data, this study clearly described and analyzed the temporal variation in VOC emission characteristics at a typical oil and gas field, which exhibited different VOC levels, compositions and origins compared with those in urban and industrial areas.

  3. Optoelectronic and Photovoltaic Properties of the Air-Stable Organohalide Semiconductor (CH 3 NH 3 ) 3 Bi 2 I 9

    KAUST Repository

    Abulikemu, Mutalifu

    2016-07-14

    Lead halide perovskite materials have shown excellent optoelectronic as well as photovoltaic properties. However, the presence of lead and the chemical instabili