Machine learning to design integral membrane channelrhodopsins for efficient eukaryotic expression and plasma membrane localization

PubMed Central

Rice, Austin J.; Gradinaru, Viviana; Arnold, Frances H.

2017-01-01

There is growing interest in studying and engineering integral membrane proteins (MPs) that play key roles in sensing and regulating cellular response to diverse external signals. A MP must be expressed, correctly inserted and folded in a lipid bilayer, and trafficked to the proper cellular location in order to function. The sequence and structural determinants of these processes are complex and highly constrained. Here we describe a predictive, machine-learning approach that captures this complexity to facilitate successful MP engineering and design. Machine learning on carefully-chosen training sequences made by structure-guided SCHEMA recombination has enabled us to accurately predict the rare sequences in a diverse library of channelrhodopsins (ChRs) that express and localize to the plasma membrane of mammalian cells. These light-gated channel proteins of microbial origin are of interest for neuroscience applications, where expression and localization to the plasma membrane is a prerequisite for function. We trained Gaussian process (GP) classification and regression models with expression and localization data from 218 ChR chimeras chosen from a 118,098-variant library designed by SCHEMA recombination of three parent ChRs. We use these GP models to identify ChRs that express and localize well and show that our models can elucidate sequence and structure elements important for these processes. We also used the predictive models to convert a naturally occurring ChR incapable of mammalian localization into one that localizes well. PMID:29059183

Impact of Formaldehyde Addition on Auto-Ignition in Internal-Combustion Engines

NASA Astrophysics Data System (ADS)

Kuwahara, Kazunari; Ando, Hiromitsu; Furutani, Masahiro; Ohta, Yasuhiko

By employing a direct-injection diesel engine equipped with a common-rail type of injection system, by adding formaldehyde (CH2O) to the intake air, and by changing the fuel-injection timing, the compression ratio and the intake-air temperature, a mechanism for CH2O as a fuel additive to affect auto-ignition was discussed. Unlike an HCCI type of engine, the diesel engine can expose an air-fuel mixture only to a limited range of the in-cylinder temperature before the ignition, and can separate low- and high-temperature parts of the mechanism. When low-temperature oxidation starts at a temperature above 900K, there are cases that the CH2O advances the ignition timing. Below 900K, to the contrary, it always retards the timing. It is because, above 900K, a part of the CH2O changes into CO together with H2O2 as an ignition promoter. Below 900K, on the other hand, the CH2O itself acts as an OH radical scavenger against cool-flame reaction, from the beginning of low-temperature oxidation. Then, the engine was modified for its extraordinary function as a gasoline-knocking generator, in order that an effect of CH2O on knocking could be discussed. The CH2O retards the onset of auto-ignition of an end gas. Judging from a large degree of the retardation, the ignition is probably triggered below 900K.

Setup in the Icing Research Tunnel Test Section

NASA Image and Video Library

1969-02-21

Technicians set up test hardware inside the test section of the Icing Research Tunnel at the National Aeronautics and Space Administration (NASA) Lewis Research Center. The Icing Research Tunnel was built in the early 1940s to study the formation of ice on aircraft surfaces and develop methods of preventing or eradicating that ice. Ice buildup is dangerous because it adds extra weight, effects aerodynamics, and sometimes blocks air flow through engines. The Icing Research Tunnel is a closed-loop atmospheric wind tunnel with a 6- by 9-foot test section. The tunnel can produce speeds up to 300 miles per hour and temperatures from 30 to -45 °F. NACA engineers struggled initially to perfect a spray bar system to introduce moisture into the airstream. The tunnel was shut down in the late 1950s as the center focused its energy exclusively on space. Industrial customers began using the tunnel sporadically, then steadily, in the 1960s. Boeing, Aerojet, Lockheed, Sikorsky, Beech and others ran tests during the 1960s. Boeing analyzed engine inlets for the CH-47 Chinook, CH-46 (Sea Knight) and CH-113. This photograph was taken during a series of 100 ice-phobic coatings for the Federal Aviation Administration. They found that many of the coatings reduced ice adhesion to the test sample, but they could not be used for aircraft applications.

A Low-Ambiguity Signal Waveform for Pseudolite Positioning Systems Based on Chirp.

PubMed

Liu, Qing; Huang, Zhigang; Kou, Yanhong; Wang, Jinling

2018-04-25

Signal modulation is an essential design factor of a positioning system, which directly impacts the system’s potential performance. Chirp compressions have been widely applied in the fields of communication, radar, and indoor positioning owing to their high compression gain and good resistance to narrowband interferences and multipath fading. Based on linear chirp, we present a modulation method named chirped pseudo-noise (ChPN). The mathematical model of the ChPN signal is provided with its auto-correlation function (ACF) and the power spectrum density (PSD) derived. The ChPN with orthogonal chirps is also discussed, which has better resistance to near-far effect. Then the generation and detection methods as well as the performances of ChPN are discussed by theoretical analysis and simulation. The results show that, for ChPN signals with the same main-lobe bandwidth (MLB), generally, the signal with a larger sweep bandwidth has better tracking precision and multipath resistance. ChPN yields slighter ACF peaks ambiguity due to its lower ACF side-peaks, although its tracking precision is a little worse than that of a binary offset carrier (BOC) with the same MLB. Moreover, ChPN provides better overall anti-multipath performance than BOC. For the ChPN signals with the same code rate, a signal with a larger sweep bandwidth has better performance in most aspects. In engineering practice, a ChPN receiver can be implemented by minor modifications of a BOC receiver. Thus, ChPN modulation shows promise for future positioning applications.

Efficient sequence-specific isolation of DNA fragments and chromatin by in vitro enChIP technology using recombinant CRISPR ribonucleoproteins.

PubMed

Fujita, Toshitsugu; Yuno, Miyuki; Fujii, Hodaka

2016-04-01

The clustered regularly interspaced short palindromic repeats (CRISPR) system is widely used for various biological applications, including genome editing. We developed engineered DNA-binding molecule-mediated chromatin immunoprecipitation (enChIP) using CRISPR to isolate target genomic regions from cells for their biochemical characterization. In this study, we developed 'in vitro enChIP' using recombinant CRISPR ribonucleoproteins (RNPs) to isolate target genomic regions. in vitro enChIP has the great advantage over conventional enChIP of not requiring expression of CRISPR complexes in cells. We first showed that in vitro enChIP using recombinant CRISPR RNPs can be used to isolate target DNA from mixtures of purified DNA in a sequence-specific manner. In addition, we showed that this technology can be used to efficiently isolate target genomic regions, while retaining their intracellular molecular interactions, with negligible contamination from irrelevant genomic regions. Thus, in vitro enChIP technology is of potential use for sequence-specific isolation of DNA, as well as for identification of molecules interacting with genomic regions of interest in vivo in combination with downstream analysis. © 2016 The Authors. Genes to Cells published by Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

Additively Manufactured Combustion Devices Components for LOX/Methane Applications

NASA Technical Reports Server (NTRS)

Greene, Sandra Elam; Protz, Christopher; Garcia, Chance; Goodman, Dwight; Baker, Kevin

2016-01-01

Marshall Space Flight Center (MSFC) has designed, fabricated, and hot-fire tested a variety of successful injectors, chambers, and igniters for potential liquid oxygen (LOX) and methane (CH4) systems since 2005. The most recent efforts have focused on components with additive manufacturing (AM) to include unique design features, minimize joints, and reduce final machining efforts. Inconel and copper alloys have been used with AM processes to produce a swirl coaxial injector and multiple methane cooled thrust chambers. The initial chambers included unique thermocouple ports for measuring local coolant channel temperatures along the length of the chamber. Results from hot-fire testing were used to anchor thermal models and generate a regeneratively cooled thruster for a 4,000 lbf LOX/CH4 engine. The completed thruster will be hot-fire tested in the summer of 2016 at MSFC. The thruster design can also be easily scaled and used on a 25,000 lbf engine. To further support the larger engine design, an AM gas generator injector has been designed. Hot-fire testing on this injector is planned for the summer of 2016 at MSFC.

The Effect of Stabilization Treatments on Disk Alloy CH98

NASA Technical Reports Server (NTRS)

Gayda, John; Gabb, Timothy P.; Ellis, David L.

2003-01-01

Gas turbine engines for future subsonic transports will probably have higher pressure ratios which will require nickelbase superalloy disks with 1300 to 1400 F temperature capability. Several advanced disk alloys are being developed to fill this need. One of these, CH98, is a promising candidate for gas turbine engines and is being studied in NASA s Advanced Subsonic Technology (AST) program. For large disks, residual stresses generated during quenching from solution heat treatments are often reduced by a stabilization heat treatment, in which the disk is heated to 1500 or 1600 F for several hours followed by a static air cool. The reduction in residual stress levels lessens distortion during machining of disks. However, previous work on CH98 has indicated that stabilization treatments can also decrease creep capability. In this study, a systematic variation of stabilization temperature and time was investigated to determine its effect on 1300 F tensile and, more importantly, creep behavior. Dwell crack growth rates were also measured for selected stabilization conditions. As these advanced disk alloys may be given a supersolvus solution or a subsolvus solution heat treatment for a given application, it was decided that both options would be studied.

Engineered antibody CH2 domains binding to nucleolin: Isolation, characterization and improvement of aggregation.

PubMed

Li, Dezhi; Gong, Rui; Zheng, Jun; Chen, Xihai; Dimitrov, Dimiter S; Zhao, Qi

2017-04-01

Smaller recombinant antibody fragments are now emerging as alternatives of conventional antibodies. Especially, immunoglobulin (Ig) constant CH2 domain and engineered CH2 with improved stability are promising as scaffolds for selection of specific binders to various antigens. We constructed a yeast display library based on an engineered human IgG1 CH2 scaffold with diversified loop regions. A group of CH2 binders were isolated from this yeast display library by panning against nucleolin, which is a tumor-associated antigen involved in cell proliferation, tumor cell growth and angiogenesis. Out of 20 mutants, we selected 3 clones exhibiting relatively high affinities to nucleolin on yeasts. However, recombinant CH2 mutants aggregated when they were expressed. To find the mechanism of the aggregation, we employed computational prediction approaches through structural homology models of CH2 binders. The analysis of potential aggregation prone regions (APRs) and solvent accessible surface areas (ASAs) indicated two hydrophobic residues, Val 264 and Leu 309 , in the β-sheet, in which replacement of both charged residues led to significant decrease of the protein aggregation. The newly identified CH2 binders could be improved to use as candidate therapeutics or research reagents in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

Combustion characteristics of an SI engine fueled with biogas fuel

NASA Astrophysics Data System (ADS)

Chen, Lei; Long, Wuqiang; Song, Peng

2017-04-01

An experimental research of the effect of H2 substitution and CO2 dilution on CH4 combustion has been carried out on a spark ignition engine. The results show that H2 addition could improve BMEP, thermal efficiency, CO and THC emissions. NOX emissions increased for higher low heating value (LHV) of H2 than CH4. CO2 dilution could effective reduce NOX emission of H2-CH4 combustion. Although engine performance, thermal efficiency and exhaust get unacceptable under high fuel dilution ratio (F.D.R.) conditions, it could be solved by decreasing F.D.R. and/or increasing hydrogen substitution ratio (H.S.R.).

A Low-Ambiguity Signal Waveform for Pseudolite Positioning Systems Based on Chirp

PubMed Central

Huang, Zhigang; Kou, Yanhong; Wang, Jinling

2018-01-01

Signal modulation is an essential design factor of a positioning system, which directly impacts the system’s potential performance. Chirp compressions have been widely applied in the fields of communication, radar, and indoor positioning owing to their high compression gain and good resistance to narrowband interferences and multipath fading. Based on linear chirp, we present a modulation method named chirped pseudo-noise (ChPN). The mathematical model of the ChPN signal is provided with its auto-correlation function (ACF) and the power spectrum density (PSD) derived. The ChPN with orthogonal chirps is also discussed, which has better resistance to near-far effect. Then the generation and detection methods as well as the performances of ChPN are discussed by theoretical analysis and simulation. The results show that, for ChPN signals with the same main-lobe bandwidth (MLB), generally, the signal with a larger sweep bandwidth has better tracking precision and multipath resistance. ChPN yields slighter ACF peaks ambiguity due to its lower ACF side-peaks, although its tracking precision is a little worse than that of a binary offset carrier (BOC) with the same MLB. Moreover, ChPN provides better overall anti-multipath performance than BOC. For the ChPN signals with the same code rate, a signal with a larger sweep bandwidth has better performance in most aspects. In engineering practice, a ChPN receiver can be implemented by minor modifications of a BOC receiver. Thus, ChPN modulation shows promise for future positioning applications. PMID:29693581

Improved Orange and Red Ca2+ Indicators and Photophysical Considerations for Optogenetic Applications

PubMed Central

2013-01-01

We have used protein engineering to expand the palette of genetically encoded calcium ion (Ca2+) indicators to include orange and improved red fluorescent variants, and validated the latter for combined use with optogenetic activation by channelrhodopsin-2 (ChR2). These indicators feature intensiometric signal changes that are 1.7- to 9.7-fold improved relatively to the progenitor Ca2+ indicator, R-GECO1. In the course of this work, we discovered a photoactivation phenomenon in red fluorescent Ca2+ indicators that, if not appreciated and accounted for, can cause false-positive artifacts in Ca2+ imaging traces during optogenetic activation with ChR2. We demonstrate, in both a beta cell line and slice culture of developing mouse neocortex, that these artifacts can be avoided by using an appropriately low intensity of blue light for ChR2 activation. PMID:23452507

Development of Useful Biomaterial for Bone Tissue Engineering by Incorporating Nano-Copper-Zinc Alloy (nCuZn) in Chitosan/Gelatin/Nano-Hydroxyapatite (Ch/G/nHAp) Scaffold.

PubMed

Forero, Juan Carlos; Roa, Eduardo; Reyes, Juan G; Acevedo, Cristian; Osses, Nelson

2017-10-17

Ceramic and metallic nanoparticles can improve the mechanical and biological properties of polymeric scaffolds for bone tissue engineering (BTE). In this work, nanohydroxyapatite (nHAp) and nano-copper-zinc alloy (nCuZn) were added to a chitosan/gelatin (Ch/G) scaffold in order to investigate the effects on morphological, physical, and biocompatibility properties. Scaffolds were fabricated by a freeze-drying technique using different pre-freezing temperatures. Microstructure and morphology were studied by scanning electron microscopy (SEM), glass transition ( T g ) was studied using differential scanning calorimetry (DSC), cell growth was estimated by MTT assay, and biocompatibility was examined in vitro and in vivo by histochemistry analyses. Scaffolds and nanocomposite scaffolds presented interconnected pores, high porosity, and pore size appropriate for BTE. T g of Ch/G scaffolds was diminished by nanoparticle inclusion. Mouse embryonic fibroblasts (MEFs) cells loaded in the Ch/G/nHAp/nCuZn nanocomposite scaffold showed suitable behavior, based on cell adhesion, cell growth, alkaline phosphatase (ALP) activity as a marker of osteogenic differentiation, and histological in vitro cross sections. In vivo subcutaneous implant showed granulation tissue formation and new tissue infiltration into the scaffold. The favorable microstructure, coupled with the ability to integrate nanoparticles into the scaffold by freeze-drying technique and the biocompatibility, indicates the potential of this new material for applications in BTE.

Bioinspired double polysaccharides-based nanohybrid scaffold for bone tissue engineering.

PubMed

Fan, Tiantang; Chen, Jingdi; Pan, Panpan; Zhang, Yujue; Hu, Yimin; Liu, Xiaocui; Shi, Xuetao; Zhang, Qiqing

2016-11-01

The fabrication of bone scaffolds with interconnected porous structure, adequate mechanical properties and excellent biocompatibility presents a great challenge. Herein, a hybrid nanostructured chitosan/chondroitin sulfate/hydroxyapatite (ChS/CSA/HAP) in situ composite scaffold was prepared by in situ fabrication and freeze-drying technique. The composition and morphology of scaffold were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). It proved that the low crystallinity of HAP crystals were uniformly distributed in ChS/CSA organic matrix and the nanostructured hybrid scaffold exhibited good mechanical property. The biocompatibility and in vitro bioactivity were detected by MTT-assay, maturation (alkaline phosphatase (ALP) activity), Hoechst 33258 and PI fluorescence staining. In vitro tests indicated that the hybrid scaffold not only promoted the adhesion and proliferation of osteoblasts, but also improved the growth of the osteoblasts. Therefore, it is promising for bone repair application in bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Emissions Control in Swirl Stabilized Spray Combusters, an Experimental and Computational Study

DTIC Science & Technology

2007-02-01

dynamics and thus provide an attractive alternative for application in aircraft gas turbine engines. Triple Annular Research Swirler, which has been...octagonal combustor because it provided optical access for flame imaging while avoiding difficulty of drilling thermocouple access holes on the...indicated by the temperature distribution. c. OH* chemiluminescence image It is commonly accepted that CH* and OH* chemiluminescence represents reaction or

Testing and analysis of the impact on engine cycle parameters and control system modifications using hydrogen or methane as fuel in an industrial gas turbine

NASA Astrophysics Data System (ADS)

Funke, H. H.-W.; Keinz, J.; Börner, S.; Hendrick, P.; Elsing, R.

2016-07-01

The paper highlights the modification of the engine control software of the hydrogen (H2) converted gas turbine Auxiliary Power Unit (APU) GTCP 36-300 allowing safe and accurate methane (CH4) operation achieved without mechanical changes of the metering unit. The acceleration and deceleration characteristics of the engine controller from idle to maximum load are analyzed comparing H2 and CH4. Also, the paper presents the influence on the thermodynamic cycle of gas turbine resulting from the different fuels supported by a gas turbine cycle simulation of H2 and CH4 using the software GasTurb.

40 CFR 1065.660 - THC, NMHC, and CH4 determination.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false THC, NMHC, and CH4 determination. 1065... POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.660 THC, NMHC, and CH4 determination. (a) THC determination and initial THC/CH 4 contamination corrections. (1) If we...

40 CFR 1065.660 - THC, NMHC, and CH4 determination.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false THC, NMHC, and CH4 determination. 1065... POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.660 THC, NMHC, and CH4 determination. (a) THC determination and initial THC/CH 4 contamination corrections. (1) If we...

40 CFR 1065.660 - THC, NMHC, and CH4 determination.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false THC, NMHC, and CH4 determination. 1065... POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.660 THC, NMHC, and CH4 determination. (a) THC determination and initial THC/CH 4 contamination corrections. (1) If we...

40 CFR 1065.660 - THC, NMHC, and CH4 determination.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false THC, NMHC, and CH4 determination. 1065... POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.660 THC, NMHC, and CH4 determination. (a) THC determination and THC/CH 4 initial contamination corrections. (1) If we...

Human Engineering Design Criteria for Modern Control/Display Components and Standard Parts. Addendum. Recommended Modifications to MIL-STD-1472B; Selected Sections on Controls, Displays and Related Hardware

DTIC Science & Technology

1980-05-01

be used in any application in which its movement is likely to be ambiguously interpreted . (Example--the manipulation required is opposite to that...fixtures shall be sufficient to permit unambiguous labeling, indicator interpretation , and convenient bulb removal. 5.2.2.3.3 Codinq - Simple...low-resolution for Imagery Interpretation applications, line spacing need not be closer than needed to sub- Equipment, 1975, Ch. 4. tend I minute-of

Consider the DME alternative for diesel engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleisch, T.H.; Meurer, P.C.

1996-07-01

Engine tests demonstrate that dimethyl ether (DME, CH{sub 3}OCH{sub 3}) can provide an alternative approach toward efficient, ultra-clean and quiet compression ignition (CI) engines. From a combustion point of view, DME is an attractive alternative fuel for CI engines, primarily for commercial applications in urban areas, where ultra-low emissions will be required in the future. DME can resolve the classical diesel emission problem of smoke emissions, which are completely eliminated. With a properly developed DME injection and combustion system, NO{sub x} emissions can be reduced to 40% of Euro II or U.S. 1998 limits, and can meet the future ULEVmore » standards of California. Simultaneously, the combustion noise is reduced by as much as 15 dB(A) below diesel levels. In addition, the classical diesel advantages such as high thermal efficiency, compression ignition, engine robustness, etc., are retained.« less

Incorporation of Data Analysis throughout the ChE Curriculum Made Easy with DataFit

ERIC Educational Resources Information Center

Brenner, James R.

2007-01-01

At Florida Tech, we have incorporated DataFit from Oakdale Engineering throughout the entire curriculum, beginning with ChE 1102, an eight-week, one-day-per-week, two-hour, one-credit-hour, second-semester Introduction to Chemical Engineering course in a hands-on computer classroom. Our experience is that students retain data analysis concepts…

Electrospinning of Chitosan-Based Solutions for Tissue Engineering and Regenerative Medicine

PubMed Central

Qasim, Saad B.; Khurshid, Zohaib; Shah, Altaf H.; Husain, Shehriar; Rehman, Ihtesham Ur

2018-01-01

Electrospinning has been used for decades to generate nano-fibres via an electrically charged jet of polymer solution. This process is established on a spinning technique, using electrostatic forces to produce fine fibres from polymer solutions. Amongst, the electrospinning of available biopolymers (silk, cellulose, collagen, gelatine and hyaluronic acid), chitosan (CH) has shown a favourable outcome for tissue regeneration applications. The aim of the current review is to assess the current literature about electrospinning chitosan and its composite formulations for creating fibres in combination with other natural polymers to be employed in tissue engineering. In addition, various polymers blended with chitosan for electrospinning have been discussed in terms of their potential biomedical applications. The review shows that evidence exists in support of the favourable properties and biocompatibility of chitosan electrospun composite biomaterials for a range of applications. However, further research and in vivo studies are required to translate these materials from the laboratory to clinical applications. PMID:29385727

Calcium Silicate/Chitosan-Coated Electrospun Poly (Lactic Acid) Fibers for Bone Tissue Engineering.

PubMed

Su, Chu-Jung; Tu, Ming-Gene; Wei, Li-Ju; Hsu, Tuan-Ti; Kao, Chia-Tze; Chen, Tsui-Han; Huang, Tsui-Hsien

2017-05-05

Electrospinning technology allows fabrication of nano- or microfibrous fibers with inorganic and organic matrix and it is widely applied in bone tissue engineering as it allows precise control over the shapes and structures of the fibers. Natural bone has an ordered composition of organic fibers with dispersion of inorganic apatite among them. In this study, poly (lactic acid) (PLA) mats were fabricated with electrospinning and coated with chitosan (CH)/calcium silicate (CS) mixer. The microstructure, chemical component, and contact angle of CS/CH-PLA composites were analyzed by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. In vitro, various CS/CH-coated PLA mats increased the formation of hydroxyapatite on the specimens' surface when soaked in cell cultured medium. During culture, several biological characteristics of the human mesenchymal stem cells (hMSCs) cultured on CS/CH-PLA groups were promoted as compared to those on pure PLA mat. Increased secretion levels of Collagen I and fibronectin were observed in calcium silicate-powder content. Furthermore, with comparison to PLA mats without CS/CH, CS10 and CS15 mats markedly enhanced the proliferation of hMSCs and their osteogenesis properties, which was characterized by osteogenic-related gene expression. These results clearly demonstrated that the biodegradable and electroactive CS/CH-PLA composite mats are an ideal and suitable candidate for bone tissue engineering.

Engine system assessment study using Martian propellants

NASA Technical Reports Server (NTRS)

Pelaccio, Dennis; Jacobs, Mark; Scheil, Christine; Collins, John

1992-01-01

A top-level feasibility study was conducted that identified and characterized promising chemical propulsion system designs which use two or more of the following propellant combinations: LOX/H2, LOX/CH4, and LOX/CO. The engine systems examined emphasized the usage of common subsystem/component hardware where possible. In support of this study, numerous mission scenarios were characterized that used various combinations of Earth, lunar, and Mars propellants to establish engine system requirements to assess the promising engine system design concept examined, and to determine overall exploration leverage of such systems compared to state-of-the-art cryogenic (LOX/H2) propulsion systems. Initially in the study, critical propulsion system technologies were assessed. Candidate expander and gas generator cycle LOX/H2/CO, LOX/H2/CH4, and LOX/CO/CH4 engine system designs were parametrically evaluated. From this evaluation baseline, tripropellant Mars Transfer Vehicle (MTV) LOX cooled and bipropellant Lunar Excursion Vehicle (LEV) and Mars Excursion Vehicle (MEV) engine systems were identified. Representative tankage designs for a MTV were also investigated. Re-evaluation of the missions using the baseline engine design showed that in general the slightly lower performance, smaller, lower weight gas generator cycle-based engines required less overall mission Mars and in situ propellant production (ISPP) infrastructure support compared to the larger, heavier, higher performing expander cycle engine systems.

Pharmacologic suppression of target cell recognition by engineered T cells expressing chimeric T-cell receptors.

PubMed

Alvarez-Vallina, L; Yañez, R; Blanco, B; Gil, M; Russell, S J

2000-04-01

Adoptive therapy with autologous T cells expressing chimeric T-cell receptors (chTCRs) is of potential interest for the treatment of malignancy. To limit possible T-cell-mediated damage to normal tissues that weakly express the targeted tumor antigen (Ag), we have tested a strategy for the suppression of target cell recognition by engineered T cells. Jurkat T cells were transduced with an anti-hapten chTCR tinder the control of a tetracycline-suppressible promoter and were shown to respond to Ag-positive (hapten-coated) but not to Ag-negative target cells. The engineered T cells were then reacted with hapten-coated target cells at different effector to target cell ratios before and after exposure to tetracycline. When the engineered T cells were treated with tetracycline, expression of the chTCR was greatly decreased and recognition of the hapten-coated target cells was completely suppressed. Tetracycline-mediated suppression of target cell recognition by engineered T cells may be a useful strategy to limit the toxicity of the approach to cancer gene therapy.

Mitigating Methane: Emerging Technologies To Combat Climate Change's Second Leading Contributor.

PubMed

Pratt, Chris; Tate, Kevin

2018-06-05

Methane (CH 4 ) is the second greatest contributor to anthropogenic climate change. Emissions have tripled since preindustrial times and continue to rise rapidly, given the fact that the key sources of food production, energy generation and waste management, are inexorably tied to population growth. Until recently, the pursuit of CH 4 mitigation approaches has tended to align with opportunities for easy energy recovery through gas capture and flaring. Consequently, effective abatement has been largely restricted to confined high-concentration sources such as landfills and anaerobic digesters, which do not represent a major share of CH 4 's emission profile. However, in more recent years we have witnessed a quantum leap in the sophistication, diversity and affordability of CH 4 mitigation technologies on the back of rapid advances in molecular analytical techniques, developments in material sciences and increasingly efficient engineering processes. Here, we present some of the latest concepts, designs and applications in CH 4 mitigation, identifying a number of abatement synergies across multiple industries and sectors. We also propose novel ways to manipulate cutting-edge technology approaches for even more effective mitigation potential. The goal of this review is to stimulate the ongoing quest for and uptake of practicable CH 4 mitigation options; supplementing established and proven approaches with immature yet potentially high-impact technologies. There has arguably never been, and if we do not act soon nor will there be, a better opportunity to combat climate change's second most significant greenhouse gas.

Assessing Sediment Transport at Navy Facilities (User’s Guide)

DTIC Science & Technology

2007-09-01

Mytilus edulis), a soft shell clam (Mya arenaria), hairy sea cucumbers (Sclerodactyla briareus), lobsters (Homarus americanus), purple sea urchins ...Diego P. J. White CH2M HILL C. A. Jones Sea Engineering, Inc. Approved for public release; distribution is unlimited. SSC San Diego...Diego P. J. White CH2M HILL C. A. Jones Sea Engineering, Inc. Approved for public release; distribution is unlimited. SSC San Diego San

40 CFR 1051.501 - What procedures must I use to test my vehicles or engines?

Code of Federal Regulations, 2013 CFR

2013-07-01

... production-line testing requirements. (a) Snowmobiles. For snowmobiles, use the equipment and procedures for.... Measure CO2, N2O, and CH4 as described in § 1051.235. Use the duty cycle specified in § 1051.505. (b.... Measure CO2, N2O, and CH4 as described in § 1051.235. If we allow you to certify ATVs based on engine...

40 CFR 1051.501 - What procedures must I use to test my vehicles or engines?

Code of Federal Regulations, 2014 CFR

2014-07-01

... production-line testing requirements. (a) Snowmobiles. For snowmobiles, use the equipment and procedures for.... Measure CO2, N2O, and CH4 as described in § 1051.235. Use the duty cycle specified in § 1051.505. (b.... Measure CO2, N2O, and CH4 as described in § 1051.235. If we allow you to certify ATVs based on engine...

40 CFR 1051.501 - What procedures must I use to test my vehicles or engines?

Code of Federal Regulations, 2010 CFR

2010-07-01

... production-line testing requirements. (a) Snowmobiles. For snowmobiles, use the equipment and procedures for.... Measure CO2, N2O, and CH4 as described in § 1051.235. Use the duty cycle specified in § 1051.505. (b.... Measure CO2, N2O, and CH4 as described in § 1051.235. If we allow you to certify ATVs based on engine...

40 CFR 1051.501 - What procedures must I use to test my vehicles or engines?

Code of Federal Regulations, 2011 CFR

2011-07-01

... production-line testing requirements. (a) Snowmobiles. For snowmobiles, use the equipment and procedures for.... Measure CO2, N2O, and CH4 as described in § 1051.235. Use the duty cycle specified in § 1051.505. (b.... Measure CO2, N2O, and CH4 as described in § 1051.235. If we allow you to certify ATVs based on engine...

40 CFR 1051.501 - What procedures must I use to test my vehicles or engines?

Code of Federal Regulations, 2012 CFR

2012-07-01

... production-line testing requirements. (a) Snowmobiles. For snowmobiles, use the equipment and procedures for.... Measure CO2, N2O, and CH4 as described in § 1051.235. Use the duty cycle specified in § 1051.505. (b.... Measure CO2, N2O, and CH4 as described in § 1051.235. If we allow you to certify ATVs based on engine...

Aligned Carbon Nanotube Carpets on Carbon Substrates for High Power Electronic Applications

DTIC Science & Technology

2016-06-01

SiOx by a vapor-solid-solid mechanism ,” J. Am. Chem. Soc., vol. 133, pp. 197–199, 2011. [146] B. Liu, W. Ren, C. Liu, C.-H. Sun , L. Gao, S. Li, C... Mechanical and Thermal Systems Branch Power and Control Division JUNE 2016 Interim Report DISTRIBUTION STATEMENT A: Approved for public release...Advisor Program Engineer Mechanical and Thermal Systems Branch Mechanical and Thermal Systems Branch Power and Control Division Power and Control

Hydroxylation of organic polymer surface: method and application.

PubMed

Yang, Peng; Yang, Wantai

2014-03-26

It may be hardly believable that inert C-H bonds on a polymeric material surface could be quickly and efficiently transformed into C-OH by a simple and mild way. Thanks to the approaches developed recently, it is now possible to transform surface H atoms of a polymeric substrate into monolayer OH groups by a simple/mild photochemical reaction. Herein the method and application of this small-molecular interfacial chemistry is highlighted. The existence of hydroxyl groups on material surfaces not only determines the physical and chemical properties of materials but also provides effective reaction sites for postsynthetic sequential modification to fulfill the requirements of various applications. However, organic synthetic materials based on petroleum, especially polyolefins comprise mainly C and H atoms and thus present serious surface problems due to low surface energy and inertness in reactivity. These limitations make it challenging to perform postsynthetic surface sequential chemical derivatization toward enhanced functionalities and properties and also cause serious interfacial problems when bonding or integrating polymer substrates with natural or inorganic materials. Polymer surface hydroxylation based on direct conversion of C-H bonds on polymer surfaces is thus of significant importance for academic and practical industrial applications. Although highly active research results have reported on small-molecular C-H bond activation in solution (thus homogeneous), most of them, featuring the use of a variety of transition metals as catalysts, present a slow reaction rate, a low atom economy and an obvious environmental pollution. In sharp contrast to these conventional C-H activation strategies, the present Spotlight describes a universal confined photocatalytic oxidation (CPO) system that is able to directly convert polymer surface C-H bonds to C-OSO3(-) and, subsequently, to C-OH through a simple hydrolysis. Generally speaking, these newly implanted hydroxyl groups preserve their own reactivity toward other complementary compounds, thus creating a novel base with distinct surface properties. Thanks to this functionalized platform, a wide range of organic, inorganic and metal materials have been attached to conventional organic polymer substrates through the rational engineering of surface molecular templates from small functional groups to macromolecules. It is expected that the proposed novel CPO method and its versatile usages in advanced material applications will offer new opportunities for a variety of scientific communities, especially for those working on surface/interface modulation.

Visualizing the enteric nervous system using genetically engineered double reporter mice: Comparison with immunofluorescence.

PubMed

Jiang, Yanfen; Dong, Hui; Eckmann, Lars; Hanson, Elaine M; Ihn, Katherine C; Mittal, Ravinder K

2017-01-01

The enteric nervous system (ENS) plays a crucial role in the control of gastrointestinal motility, secretion and absorption functions. Immunohistochemistry has been widely used to visualize neurons of the ENS for more than two decades. Genetically engineered mice that report specific proteins can also be used to visualize neurons of the ENS. The goal of our study was to develop a mouse that expresses fluorescent neuronal nitric oxide synthase (nNOS) and choline acetyltransferase (ChAT), the two proteins expressed in 95% of the ENS neurons. We compared ENS neurons visualized in the reporter mouse with the wild type mouse stained using classical immunostaining techniques. Mice hemizygous for ChAT-ChR2-YFP BAC transgene with expression of the mhChR2:YFP fusion protein directed by ChAT promoter/enhancer regions on the BAC transgene were purchased commercially. The Cre/LoxP technique of somatic recombination was used to construct mice with nNOS positive neurons. The two mice were crossbred and tissues were harvested and examined using fluorescent microscopy. Immunostaining was performed in the wild type mice, using antibodies to nNOS, ChAT, Hu and PGP 9.5. Greater than 95% of the ENS neurons were positive for either nNOS or ChAT or both. The nNOS and ChAT neurons and their processes in the ENS were well visualized in all the regions of the GI tract, i.e., esophagus, small intestine and colon. The number of nNOS and ChAT neurons was approximately same in the reporter mouse and immunostaining method in the wild type mouse. The nNOS fluorescence in the reporter mouse was seen in both cytoplasm as well as nucleus but in the immunostained specimens it was seen only in the cytoplasm. We propose that the genetically engineered double reporter mouse for ChAT and nNOS proteins is a powerful tool to study of the effects of various diseases on the ENS without the need for immunostaining.

ChIP and ChIP-Related Techniques: Expanding the Fields of Application and Improving ChIP Performance.

PubMed

Visa, Neus; Jordán-Pla, Antonio

2018-01-01

Protein-DNA interactions in vivo can be detected and quantified by chromatin immunoprecipitation (ChIP). ChIP has been instrumental for the advancement of epigenetics and has set the groundwork for the development of a number of ChIP-related techniques that have provided valuable information about the organization and function of genomes. Here, we provide an introduction to ChIP and discuss the applications of ChIP in different research areas. We also review some of the strategies that have been devised to improve ChIP performance.

Bandgap Engineering of Stable Lead-Free Oxide Double Perovskites for Photovoltaics.

PubMed

Sun, Qingde; Wang, Jing; Yin, Wan-Jian; Yan, Yanfa

2018-04-01

Despite the rapid progress in solar power conversion efficiency of archetype organic-inorganic hybrid perovskite CH 3 NH 3 PbI 3 -based solar cells, the long-term stability and toxicity of Pb remain the main challenges for the industrial deployment, leading to more uncertainties for global commercialization. The poor stabilities of CH 3 NH 3 PbI 3 -based solar cells may not only be attributed to the organic molecules but also the halides themself, most of which exhibit intrinsic instability under moisture and light. As an alternative, the possibility of oxide perovskites for photovoltaic applications is explored here. The class of lead-free stable oxide double perovskites A 2 M(III)M(V)O 6 (A = Ca, Sr, Ba; M(III) = Sb 3+ or Bi 3+ ; M(V) = V 5+ , Nb 5+ , or Ta 5+ ) is comprehensively explored with regard to their stability and their electronic and optical properties. Apart from the strong stability, this class of double perovskites exhibits direct bandgaps ranging from 0.3 to 3.8 eV. With proper B site alloying, the bandgap can be tuned within the range of 1.0-1.6 eV with optical absorptions as strong as CH 3 NH 3 PbI 3 , making them suitable for efficient single-junction thin-film solar cell application. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combining vibrational biomolecular spectroscopy with chemometric techniques for the study of response and sensitivity of molecular structures/functional groups mainly related to lipid biopolymer to various processing applications.

PubMed

Yu, Gloria Qingyu; Yu, Peiqiang

2015-09-01

The objectives of this project were to (1) combine vibrational spectroscopy with chemometric multivariate techniques to determine the effect of processing applications on molecular structural changes of lipid biopolymer that mainly related to functional groups in green- and yellow-type Crop Development Centre (CDC) pea varieties [CDC strike (green-type) vs. CDC meadow (yellow-type)] that occurred during various processing applications; (2) relatively quantify the effect of processing applications on the antisymmetric CH3 ("CH3as") and CH2 ("CH2as") (ca. 2960 and 2923 cm(-1), respectively), symmetric CH3 ("CH3s") and CH2 ("CH2s") (ca. 2873 and 2954 cm(-1), respectively) functional groups and carbonyl C=O ester (ca. 1745 cm(-1)) spectral intensities as well as their ratios of antisymmetric CH3 to antisymmetric CH2 (ratio of CH3as to CH2as), ratios of symmetric CH3 to symmetric CH2 (ratio of CH3s to CH2s), and ratios of carbonyl C=O ester peak area to total CH peak area (ratio of C=O ester to CH); and (3) illustrate non-invasive techniques to detect the sensitivity of individual molecular functional group to the various processing applications in the recently developed different types of pea varieties. The hypothesis of this research was that processing applications modified the molecular structure profiles in the processed products as opposed to original unprocessed pea seeds. The results showed that the different processing methods had different impacts on lipid molecular functional groups. Different lipid functional groups had different sensitivity to various heat processing applications. These changes were detected by advanced molecular spectroscopy with chemometric techniques which may be highly related to lipid utilization and availability. The multivariate molecular spectral analyses, cluster analysis, and principal component analysis of original spectra (without spectral parameterization) are unable to fully distinguish the structural differences in the antisymmetric and symmetric CH3 and CH2 spectral region (ca. 3001-2799 cm(-1)) and carbonyl C=O ester band region (ca. 1771-1714 cm(-1)). This result indicated that the sensitivity to detect treatment difference by multivariate analysis of cluster analysis (CLA) and principal components analysis (PCA) might be lower compared with univariate molecular spectral analysis. In the future, other more sensitive techniques such as "discriminant analysis" could be considered for discriminating and classifying structural differences. Molecular spectroscopy can be used as non-invasive technique to study processing-induced structural changes that are related to lipid compound in legume seeds.

Hypergolic Combustion Demonstration in a Reciprocating Internal Combustion Engine

DTIC Science & Technology

1984-05-01

deposit problem encountered with Pearl Kerosene. Specifications and properties data for JP-7 fuel are in Table 5-2. 5.5.3. Methanol. Methanol ( CH OH...methylphenol, 0./1,000 bbls. 8.4 max. 8.4 PWA536, PPM 200-250 225 27 ’, •X TABLE 5-3. Typical Properties for Methanol(8) Formula CH 0,i Molecular weight 32.&2...46_ LIST OF REFERENCES (1) Hopple, L. 0. "Pyrophoric Combustion in Internal Combustion Engines," Eaton Technical Report No. 7845 , 1978. (2) Hoppie

77 FR 21587 - Bayer Cropscience, LP, Including On-Site Leased Workers From Jacobs PSG, Middough Associates, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-10

...., Digital Management Group, Mercury Air Group, Inc., Greenwood, and Professional Maintenance of Charleston... Solutions, Becht Engineering, Engineering Support Systems, Manufacturing Management Services, US Securities, WB Wells, Belcan, American Engineers, CH2M Hill Engineers, Inc., Digital Management Group, Mercury...

Future of Chemical Engineering: Integrating Biology into the Undergraduate ChE Curriculum

ERIC Educational Resources Information Center

Mosto, Patricia; Savelski, Mariano; Farrell, Stephanie H.; Hecht, Gregory B.

2007-01-01

Integrating biology in the chemical engineering curriculum seems to be the future for chemical engineering programs nation and worldwide. Rowan University's efforts to address this need include a unique chemical engineering curriculum with an intensive biology component integrated throughout from freshman to senior years. Freshman and Sophomore…

Review of Engine/Airframe/Drive Train Dynamic Interface Development Problems

DTIC Science & Technology

1978-06-01

dynamic interface problems associated with the Cd-54, S-61, CH-53, SH-3, S-58, SH-34, S-64, BLACK HAOK, and the ABC . The ultimate benefit will be the...drive systems of the CH-3C, CH-53A, and CH-54A helicopters. Prior to the shaft failure incident, the input drive shaft sytems had accumulated in...capability of the ABC aircraft. This aircraft has a large range in forward speed, zero to 280 knots. At high aircraft speeds, the rotor speed must be reduced

Grain Size Modulation and Interfacial Engineering of CH3 NH3 PbBr3 Emitter Films through Incorporation of Tetraethylammonium Bromide.

PubMed

Jamaludin, Nur Fadilah; Yantara, Natalia; Ng, Yan Fong; Li, Mingjie; Goh, Teck Wee; Thirumal, Krishnamoorthy; Sum, Tze Chien; Mathews, Nripan; Soci, Cesare; Mhaisalkar, Subodh

2018-05-07

Metal halide perovskites have demonstrated breakthrough performances as absorber and emitter materials for photovoltaic and display applications respectively. However, despite the low manufacturing cost associated with solution-based processing, the propensity for defect formation with this technique has led to an increasing need for defect passivation. Here, we present an inexpensive and facile method to remedy surface defects through a postdeposition treatment process using branched alkylammonium cation species. The simultaneous realignment of interfacial energy levels upon incorporation of tetraethylammonium bromide onto the surface of CH 3 NH 3 PbBr 3 films contributes favorably toward the enhancement in overall light-emitting diode characteristics, achieving maximum luminance, current efficiency, and external quantum efficiency values of 11 000 cd m -2 , 0.68 cd A -1 , and 0.16 %, respectively. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photosynthates as dominant source of CH4 and CO2 in soil water and CH4 emitted to the atmosphere from paddy fields

NASA Astrophysics Data System (ADS)

Minoda, Tomomi; Kimura, Mamoto; Wada, Eitaro

1996-09-01

Emission rates of CH4 from paddy soil with and without rice straw applications were measured with pot experiments to estimate the contribution of rice straw to the total CH4 emission during the growth period of rice plants. The CH4 derived from rice straw was calculated to be 44% of the total emission. 13CO2 uptake experiments were also carried out four times from June 30 to September 13, 1994, to estimate the contribution of photosynthesized carbon to CH4 emission. The contribution percentages of photosynthesized carbon to the total CH4 emitted to the atmosphere were 3.8% around June 30, 31% around July 25, 30% around August 19, and 14% around September 13 in the treatment with rice straw applications, and 52% around July 25, 28% around August 19, and 15% around September 13 in the treatment without rice straw applications. They were calculated to be 22% and 29% for the entire growth period in the treatments with and without rice straw applications, respectively. The contribution percentages of photosynthesized carbon to the total CH4 and inorganic carbon (Σ CO2) dissolved in soil water were 1.3%, 30%, 29%, and 34% for dissolved CH4 and 3.0%, 36%, 30% and 28% for dissolved inorganic carbon around June 30, July 25, August l9, and September 13, respectively, in the treatment with rice straw applications. They were 70%, 23%, and 32% for dissolved CH4 and 31%, 16%, and 19% for dissolved inorganic carbon around July 25, August 19, and September 13, respectively, in the treatment without rice straw applications.

Application of Copper-Chitosan Nanoparticles Stimulate Growth and Induce Resistance in Finger Millet (Eleusine coracana Gaertn.) Plants against Blast Disease.

PubMed

Sathiyabama, Muthukrishnan; Manikandan, Appu

2018-02-28

Copper-chitosan nanoparticle (CuChNp) was synthesized and used to study its effect on finger millet plant as a model plant system. Our objective was to explore the efficacy of CuChNp application to control blast disease of finger millet. CuChNp was applied to finger millet either as a foliar spray or as a combined application (involving seed coat and foliar spray). Both the application methods enhanced growth profile of finger millet plants and increased yield. The increased yield was nearly 89% in combined application method. Treated finger millet plants challenged with Pyricularia grisea showed suppression of blast disease development when compared to control. Nearly 75% protection was observed in the combined application of CuChNp to finger millet plants. In CuChNp treated finger millet plants, a significant increase in defense enzymes was observed, which was detected both qualitatively and quantitatively. The suppression of blast disease correlates well with increased defense enzymes in CuChNp treated finger millet plants.

Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: Daily, intermediate, and final California cover soils

USDA-ARS?s Scientific Manuscript database

We quantified the seasonal variability of CH4, CO2, and N2O emissions from fresh refuse and daily, intermediate, and final cover materials at two California landfills. Fresh refuse fluxes (g m-2 d-1) averaged CH4 0.053[+/-0.03], CO2 135[+/-117], and N2O 0.063[+/-0.059]. Average CH4 emissions across ...

Mechanism of the Thermal Decomposition of Ethanethiol and Dimethylsulfide

NASA Astrophysics Data System (ADS)

Melhado, William Francis; Whitman, Jared Connor; Kong, Jessica; Anderson, Daniel Easton; Vasiliou, AnGayle (AJ)

2016-06-01

Combustion of organosulfur contaminants in petroleum-based fuels and biofuels produces sulfur oxides (SO_x). These pollutants are highly regulated by the EPA because they have been linked to poor respiratory health and negative environmental impacts. Therefore much effort has been made to remove sulfur compounds in petroleum-based fuels and biofuels. Currently desulfurization methods used in the fuel industry are costly and inefficient. Research of the thermal decomposition mechanisms of organosulfur species can be implemented via engineering simulations to modify existing refining technologies to design more efficient sulfur removal processes. We have used a resistively-heated SiC tubular reactor to study the thermal decomposition of ethanethiol (CH_3CH_2SH) and dimethylsulfide (CH_3SCH_3). The decomposition products are identified by two independent techniques: 118.2 nm VUV photoionization mass spectroscopy and infrared spectroscopy. The thermal cracking products for CH_3CH_2SH are CH_2CH_2, SH, and H_2S and the thermal cracking products from CH_3SCH_3 are CH_3S, CH_2S, and CH_3.

VALIDATION OF ANSYS FINITE ELEMENT ANALYSIS SOFTWARE

DOE Office of Scientific and Technical Information (OSTI.GOV)

HAMM, E.R.

2003-06-27

This document provides a record of the verification and Validation of the ANSYS Version 7.0 software that is installed on selected CH2M HILL computers. The issues addressed include: Software verification, installation, validation, configuration management and error reporting. The ANSYS{reg_sign} computer program is a large scale multi-purpose finite element program which may be used for solving several classes of engineering analysis. The analysis capabilities of ANSYS Full Mechanical Version 7.0 installed on selected CH2M Hill Hanford Group (CH2M HILL) Intel processor based computers include the ability to solve static and dynamic structural analyses, steady-state and transient heat transfer problems, mode-frequency andmore » buckling eigenvalue problems, static or time-varying magnetic analyses and various types of field and coupled-field applications. The program contains many special features which allow nonlinearities or secondary effects to be included in the solution, such as plasticity, large strain, hyperelasticity, creep, swelling, large deflections, contact, stress stiffening, temperature dependency, material anisotropy, and thermal radiation. The ANSYS program has been in commercial use since 1970, and has been used extensively in the aerospace, automotive, construction, electronic, energy services, manufacturing, nuclear, plastics, oil and steel industries.« less

Enhanced gas adsorption on graphitic substrates via defects and local curvature: A density functional theory study

DOE PAGES

Dutta, Debosruti; Wood, Brandon C.; Bhide, Shreyas Y.; ...

2014-03-24

Using van-der-Waals-corrected density functional theory calculations, we explore the possibility of engineering the local structure and morphology of high-surface-area graphene-derived materials to improve the uptake of methane and carbon dioxide for gas storage and sensing. We test the sensitivity of the gas adsorption energy to the introduction of native point defects, curvature, and the application of strain. The binding energy at topological point defect sites is inversely correlated with the number of missing carbon atoms, causing Stone–Wales defects to show the largest enhancement with respect to pristine graphene (~20%). Improvements of similar magnitude are observed at concavely curved surfaces inmore » buckled graphene sheets under compressive strain, whereas tensile strain tends to weaken gas binding. Trends for CO 2 and CH 4 are similar, although CO 2 binding is generally stronger by ~4 to 5 kJ mol –1. Furthermore, the differential between the adsorption of CO 2 and CH 4 is much higher on folded graphene sheets and at concave curvatures; this could possibly be leveraged for CH 4/CO 2 flow separation and gas-selective sensors.« less

Application of linear Raman spectroscopy for the determination of acetone decomposition.

PubMed

Eichmann, Simone Christine; Trost, Johannes; Seeger, Thomas; Zigan, Lars; Leipertz, Alfred

2011-06-06

Acetone (CH₃)₂CO is a common tracer for laser-induced fluorescence (LIF) to investigate mixture formation processes and temperature fields in combustion applications. Since the fluorescence signal is a function of temperature and pressure, calibration measurements in high pressure and high temperature cells are necessary. However, there is a lack of reliable data of tracer stability at these harsh conditions for technical application. A new method based on the effect of spontaneous Raman scattering is proposed to analyze the thermal stability of the tracer directly in the LIF calibration cell. This is done by analyzing the gas composition regarding educts and products of the reaction. First measurements at IC engine relevant conditions up to 750 K and 30 bar are presented.

Shortfall of US Citizen Science and Engineering Specialists in Defense Industry

DTIC Science & Technology

2005-06-23

lower until equilibrium is restored. *e.g.,see Ch 1 & 4, Labor Economics , Cahuc & Zylberberg, MIT Press, 2004 Neoclassical Indicators: Increased...and balls concept Cobb-Douglas – hires as a function of job seekers and vacancies. *e.g.,see Ch 9, Labor Economics , Cahuc & Zylberberg, MIT Press

Methane oxidation in an intensively cropped tropical rice field soil under long-term application of organic and mineral fertilizers.

PubMed

Nayak, D R; Babu, Y Jagadeesh; Datta, A; Adhya, T K

2007-01-01

Methane (CH4) oxidation is the only known biological sink process for mitigating atmospheric and terrestrial emissions of CH4, a major greenhouse gas. Methane oxidation in an alluvial soil planted to rice (Oryza sativa L.) under long-term application of organic (compost with a C/N ratio of 21.71), and mineral fertilizers was measured in a field-cum-laboratory incubation study. Oxidation rates were quantified in terms of decrease in the concentration of CH4 in the headspace of incubation vessels and expressed as half-life (t(1)2) values. Methane oxidation rates significantly differed among the treatments and growth stages of the rice crop. Methane oxidation rates were high at the maximum tillering and maturity stages, whereas they were low at grain-filling stage. Methane oxidation was low (t(1)2) = 15.76 d) when provided with low concentration of CH4. On the contrary, high concentration of CH4 resulted in faster oxidation (t(1)2) = 6.67 d), suggesting the predominance of "low affinity oxidation" in rice fields. Methane oxidation was stimulated following the application of mineral fertilizers or compost implicating nutrient limitation as one of the factors affecting the process. Combined application of compost and mineral fertilizer, however, inhibited CH4 oxidation probably due to N immobilization by the added compost. The positive effect of mineral fertilizer on CH4 oxidation rate was evident only at high CH4 concentration (t(1)2 = 4.80 d), while at low CH4 concentration their was considerable suppression (t(1) = 17.60 d). Further research may reveal that long-term application of fertilizers, organic or inorganic, may not inhibit CH4 oxidation.

Effective Suppression of Methane Emission by 2-Bromoethanesulfonate during Rice Cultivation.

PubMed

Waghmode, Tatoba R; Haque, Md Mozammel; Kim, Sang Yoon; Kim, Pil Joo

2015-01-01

2-bromoethanesulfonate (BES) is a structural analogue of coenzyme M (Co-M) and potent inhibitor of methanogenesis. Several studies confirmed, BES can inhibit CH4 prodcution in rice soil, but the suppressing effectiveness of BES application on CH4 emission under rice cultivation has not been studied. In this pot experiment, different levels of BES (0, 20, 40 and 80 mg kg-1) were applied to study its effect on CH4 emission and plant growth during rice cultivation. Application of BES effectively suppressed CH4 emission when compared with control soil during rice cultivation. The CH4 emission rates were significantly (P<0.001) decreased by BES application possibly due to significant (P<0.001) reduction of methnaogenic biomarkers like Co-M concentration and mcrA gene copy number (i.e. methanogenic abunadance). BES significantly (P<0.001) reduced methanogen activity, while it did not affect soil dehydrogenase activity during rice cultivation. A rice plant growth and yield parameters were not affected by BES application. The maximum CH4 reduction (49% reduction over control) was found at 80 mg kg-1 BES application during rice cultivation. It is, therefore, concluded that BES could be a suitable soil amendment for reducing CH4 emission without affecting rice plant growth and productivity during rice cultivation.

Determination of Combustion Product Radicals in a Hydrocarbon Fueled Rocket Exhaust Plume

NASA Technical Reports Server (NTRS)

Langford, Lester A.; Allgood, Daniel C.; Junell, Justin C.

2007-01-01

The identification of metallic effluent materials in a rocket engine exhaust plume indicates the health of the engine. Since 1989, emission spectroscopy of the plume of the Space Shuttle Main Engine (SSME) has been used for ground testing at NASA's Stennis Space Center (SSC). This technique allows the identification and quantification of alloys from the metallic elements observed in the plume. With the prospect of hydrocarbon-fueled rocket engines, such as Rocket Propellant 1 (RP-1) or methane (CH4) fueled engines being considered for use in future space flight systems, the contributions of intermediate or final combustion products resulting from the hydrocarbon fuels are of great interest. The effect of several diatomic molecular radicals, such as Carbon Dioxide , Carbon Monoxide, Molecular Carbon, Methylene Radical, Cyanide or Cyano Radical, and Nitric Oxide, needs to be identified and the effects of their band systems on the spectral region from 300 nm to 850 nm determined. Hydrocarbon-fueled rocket engines will play a prominent role in future space exploration programs. Although hydrogen fuel provides for higher engine performance, hydrocarbon fuels are denser, safer to handle, and less costly. For hydrocarbon-fueled engines using RP-1 or CH4 , the plume is different from a hydrogen fueled engine due to the presence of several other species, such as CO2, C2, CO, CH, CN, and NO, in the exhaust plume, in addition to the standard H2O and OH. These species occur as intermediate or final combustion products or as a result of mixing of the hot plume with the atmosphere. Exhaust plume emission spectroscopy has emerged as a comprehensive non-intrusive sensing technology which can be applied to a wide variety of engine performance conditions with a high degree of sensitivity and specificity. Stennis Space Center researchers have been in the forefront of advancing experimental techniques and developing theoretical approaches in order to bring this technology to a more mature stage.

Methane Fluxes and Consumption in an Oil Sands Tailings End Pit Lake

NASA Astrophysics Data System (ADS)

Slater, G. F.; Goad, C.; Arriaga, D.; Risacher, F.; Morris, P.; Lindsay, M. B.; Mumford, K. G.; Warren, L. A.

2017-12-01

End pit lakes are engineered freshwater lakes designed to reclaim land impacted by surface mining activities via establishment of a functioning ecosystem where biogeochemical cycling mitigates release of hazardous components either by stabilization or biodegradation. End pit lakes provide unique opportunities to gain insight into microbial nutrient cycling under extreme levels of impact that can be applicable to a range of levels of anthropogenic impacts and issues. This study focuses on microbial CH4 cycling in the underlying fluid fine tailings (FFT) and surface waters of Base Mine Lake (BML), the first full demonstration of end pit lake reclamation in the Athabasca Oil Sands Region (AOSR) of northern Alberta, Canada. Over two field seasons (2015 and 2016) BML was thermally stratified, turning over in spring and fall. Oxygen concentrations in the epilimnion (70 to 80 % saturation) decreased steeply through the metalimnion to 3% saturation in the hypolimnion. Conversely, CH4 concentrations were highest in the hypolimnion of BML (25 to 140 µM) with the highest values being observed at the FFT/Water interface. Concentrations decreased to 1-2 µM at the metalimnion and further decreased to < 0.5 µM in the epilimnion. CH4 δ13C in FFT porewater indicated production via fermentative pathways. FFT settlement and dewatering of 0.73 to 1.0 m/yr results in advection of an estimated 1x107 to 2x107 moles/yr CH4 into the surface water, circa an order of magnitude greater than the 3x106 moles/year estimated for molecular diffusion. Calculated fluxes of dissolved CH4 from the FFT into the hypolimnion were 4 orders of magnitude higher than those from the hypolimnion to the metalimnion, indicating a significant sink for CH4 within the hypolimnion limiting upward dissolved CH4 transport. Dissolution of CH4 from bubbles released from the FFT may be contributing to the observed epilimnion concentrations. CH4 δ13C in the hypolimnion showed only minimal enrichment with decreasing concentrations. However, phospholipid fatty acids of bacteria in the hypolimnion were significantly δ13C depleted indicating CH4 consumption was a primary carbon source for the microbial community in the hypolimnion. Ongoing analyses of samples from 2017 will further elucidate the development of methane biogeochemical cycling in BML.

Raman fiberoptic probe for monitoring human tissue engineered oral mucosa constructs

NASA Astrophysics Data System (ADS)

Khmaladze, Alexander; Kuo, Shiuhyang; Okagbare, Paul; Marcelo, Cynthia L.; Feinberg, Stephen E.; Morris, Michael D.

2013-02-01

In oral and maxillofacial surgery, there is a need for tissue engineered constructs for dental implants, reconstructions due to trauma, oral cancer or congenital defects. A non-invasive quality monitoring of the fabrication of tissue engineered constructs during their production and implantation is a required component of any successful tissue engineering technique. We demonstrate the design and application of a Raman spectroscopic probe for rapid and noninvasive monitoring of Ex Vivo Produced Oral Mucosa Equivalent constructs (EVPOMEs). We conducted in vivo studies to identify Raman spectroscopic failure indicators for EVPOMEs (already developed in vitro), and found that Raman spectra of EVPOMEs exposed to thermal stress showed correlation of the band height ratio of CH2 deformation to phenylalanine ring breathing modes, providing a Raman metric to distinguish between viable and nonviable constructs. This is the first step towards the ultimate goal to design a stand-alone system, which will be usable in a clinical setting, as the data processing and analysis will be performed with minimal user intervention, based on already established and tested Raman spectroscopic indicators for EVPOMEs.

COMET: An Open-Ended, Hands-On Project for ChE Sophomores.

ERIC Educational Resources Information Center

Prausnitz, Mark R.

1998-01-01

Describes Controlled-Operation Mechanical Energy Transducers (COMETs), which are part of a project to introduce sophomore chemical engineering students to a number of important engineering concepts that are usually addressed later in the academic program. (DDR)

Comparison of CH4 Emission from Rice Paddy Soils between Coastal Zone and Inland Regions

NASA Astrophysics Data System (ADS)

Sun, M.; Li, X.

2016-12-01

Numerous measurements of methane (CH4) emission fluxes have been carried out in rice paddy soil between coastal zone and inland regions. However, the differences of CH4 emission from rice paddy soils in these two locations were unavailable. A database of CH4 emission in paddy rice was compiled from previous published references and field observations with major parameters including water regimes, fertilizer application, CH4 fluxes, and environmental variables. Results showed that CH4 emission from inland paddy fields was significantly higher than that in the coastal zone (p < 0.05). Fertilizer application and water management played an important role in CH4 emission. The application of organic fertilizer and continuous flooding significantly promoted CH4 emission from paddy fields. CH4 fluxes showed significantly positive correlations with organic matter, total nitrogen, available potassium and annual temperature (R2 = 0.39, 0.53, 0.27 and 0.23, p < 0.05), and negative correlations with pH and available phosphorus (R2 = 0.29 and 0.37, p < 0.05). Significant differences occurred in available potassium between inland and coastal rice paddy (p < 0.05), which might account for the difference of CH4 emission between inland and coastal rice paddy. The contrasting of CH4 fluxes between inland and coastal wetlands could improve our understanding of the roles of rice paddies in the regional CH4 regulation. Our results also have implications for informing rice paddy management and climate change policy making the efforts being made by agricultural organizations and enterprises to restore coastal rice paddies for mitigating CH4 emissions.

Speciated Monitoring of Gas-Phase Organic Peroxy Radicals by Chemical Ionization Mass Spectrometry: Cross-Reactions between CH3O2, CH3(CO)O2, (CH3)3CO2, and c-C6H11O2.

PubMed

Nozière, Barbara; Hanson, David R

2017-11-09

Organic peroxy radicals ("RO 2 ", with R organic) are key intermediates in most oxygen-rich systems, where organic compounds are oxidized (natural environment, flames, combustion engines, living organisms, etc). But, until recently, techniques able to monitor simultaneously and distinguish between RO 2 species ("speciated" detection) have been scarce, which has limited the understanding of complex systems containing these radicals. Mass spectrometry using proton transfer ionization has been shown previously to detect individual gas-phase RO 2 separately. In this work, we illustrate its ability to speciate and monitor several RO 2 simultaneously by investigating reactions involving CH 3 O 2 , CH 3 C(O)O 2 , c-C 6 H 11 O 2 , and (CH 3 ) 3 CO 2 . The detection sensitivity of each of these radicals was estimated by titration with NO to between 50 and 1000 Hz/ppb, with a factor from 3 to 5 of uncertainties, mostly due to the uncertainties in knowing the amounts of added NO. With this, the RO 2 concentration in the reactor was estimated between 1 × 10 10 and 1 × 10 12 molecules cm -3 . When adding a second radical species to the reactor, the kinetics of the cross-reaction could be studied directly from the decay of the first radical. The time-evolution of two and sometimes three different RO 2 was followed simultaneously, as the CH 3 O 2 produced in further reaction steps was also detected in some systems. The rate coefficients obtained are (in molecule -1 cm 3 s -1 ): k CH3O2+CH3C(O)O2 = 1.2 × 10 -11 , k CH3O2+t-butylO2 = 3.0 × 10 -15 , k c-hexylO2+CH3O2 = 1.2 × 10 -13 , k t-butylO2+CH3C(O)O2 = 3.7 × 10 -14 , and k c-hexylO2+t-butylO2 = 1.5 × 10 -15 . In spite of their good comparison with the literature and good reproducibility, large uncertainties (×5/5) are recommended on these results because of those in the detection sensitivities. This work is a first illustration of the potential applications of this technique for the investigation of organic radicals in laboratory and in more complex systems.

Identifying Sources of Long-Distance Transported Pollution to the Arctic using δ13C in CH4 and Particle Dispersion Modelling

NASA Astrophysics Data System (ADS)

France, J. L.; Fisher, R. E.; Lowry, D.; Lanoiselle, M.; Cain, M.; Pyle, J. A.; Illingworth, S.; Allen, G.; Gallagher, M. W.; O'Shea, S.; Muller, J.; Bauguitte, S.; Nisbet, E. G.

2013-12-01

A stratified pollution plume of increased CH4 was identified at ~2000ft to ~7000ft altitude between the North coast of Norway and Svalbard on 21st July, 2012. The increased CH4 was identified through continuous CH4 measurements using a fast greenhouse gas analyser on board the NERC FAAM aircraft as part of the MAMM (Methane in the Arctic: Measurements and Modelling) campaign. Measurements of δ13C in CH4 on air samples taken whilst the aircraft was in the pollution plume demonstrate that the plume has a δ13C in CH4 source signature of -70 ‰. (×2.1 ‰). A δ13C source signature of -70 ‰ (×2.1 ‰) is within the expected boundaries of δ13C for wetland emissions in the Arctic (-70 to - 60‰ (Dlugokencky, Nisbet, Fisher, & Lowry, 2011)). The NAME (Numerical Atmospheric-dispersion Modelling Environment) model was run backwards from the measurement locations to identify periods where the measured air mass was in contact with the surface (lowest 300 m of the atmosphere). Combining the results together show that the likely source of the elevated methane measured is from wetlands located in North-West Russia. By sampling stratified air at altitude using the FAAM aircraft as a measurement platform, the joint application of isotopic source identification and NAME modelling allows identification of methane plumes from sources that we would otherwise not be able to sample, due to either remote access and / or political reasons (providing that suitable meteorological conditions exist). The use of this joined up approach will give us an extra tool in adding data to the global inventory of δ13C in CH4 source signatures and will enable better understanding of the sources of above background concentrations of CH4 to the Arctic. References. Dlugokencky, E. J., Nisbet, E. G., Fisher, R., & Lowry, D. (2011). Global atmospheric methane: budget, changes and dangers. Philosophical transactions. Series A, Mathematical, physical, and engineering sciences, 369(1943), 2058-72. doi:10.1098/rsta.2010.0341

The effect of sodium hypochlorite application on the success of calcium hydroxide and mineral trioxide aggregate pulpotomies in primary teeth.

PubMed

Akcay, Merve; Sari, Saziye

2014-01-01

This study's purpose was to evaluate the success of calcium hydroxide (CH) and mineral trioxide aggregate (MTA) pulpotomies following the use of five percent sodium hypochlorite (NaOCl) as an antibacterial agent to clean the chamber prior to application of the pulpotomy agent. A total of 128 teeth were randomly divided into two pulpotomy groups (CH or MTA). The teeth in each pulpotomy group, CH and MTA, were further randomly divided into subgroups to receive either the NaOCl (experimental) or saline (control) cleaning agent prior to applying the pulpotomy agent. The treatments were followed clinically and radiographically for 12 months. The radiographic success rates were 84 percent for CH NaOCl, 74 percent for CH saline control, 97 percent for MTA NaOCl, and 100 percent for MTA saline control. There were no significant differences between the radiographic success rates in the CH and MTA subgroups (CH NaOCl-CH control and MTA NaOCl-MTA control); no significant differences were observed when comparing the CH NaOCl-MTA NaOCl groups and the CH NaOCl-MTA control groups. Use of sodium hypochlorite as an antibacterial agent prior to application of the pulpotomy agent improved the success of calcium hydroxide pulpotomies to equal the success of mineral trioxide aggregate pulpotomies for observation up to 12 months.

Diffuse-Interface Modelling of Flow in Porous Media

NASA Astrophysics Data System (ADS)

Addy, Doug; Pradas, Marc; Schmuck, Marcus; Kalliadasis, Serafim

2016-11-01

Multiphase flows are ubiquitous in a wide spectrum of scientific and engineering applications, and their computational modelling often poses many challenges associated with the presence of free boundaries and interfaces. Interfacial flows in porous media encounter additional challenges and complexities due to their inherently multiscale behaviour. Here we investigate the dynamics of interfaces in porous media using an effective convective Cahn-Hilliard (CH) equation recently developed in from a Stokes-CH equation for microscopic heterogeneous domains by means of a homogenization methodology, where the microscopic details are taken into account as effective tensor coefficients which are given by a Poisson equation. The equations are decoupled under appropriate assumptions and solved in series using a classic finite-element formulation with the open-source software FEniCS. We investigate the effects of different microscopic geometries, including periodic and non-periodic, at the bulk fluid flow, and find that our model is able to describe the effective macroscopic behaviour without the need to resolve the microscopic details.

Experimental approaches to identify cellular G-quadruplex structures and functions.

PubMed

Di Antonio, Marco; Rodriguez, Raphaël; Balasubramanian, Shankar

2012-05-01

Guanine-rich nucleic acids can fold into non-canonical DNA secondary structures called G-quadruplexes. The formation of these structures can interfere with the biology that is crucial to sustain cellular homeostases and metabolism via mechanisms that include transcription, translation, splicing, telomere maintenance and DNA recombination. Thus, due to their implication in several biological processes and possible role promoting genomic instability, G-quadruplex forming sequences have emerged as potential therapeutic targets. There has been a growing interest in the development of synthetic molecules and biomolecules for sensing G-quadruplex structures in cellular DNA. In this review, we summarise and discuss recent methods developed for cellular imaging of G-quadruplexes, and the application of experimental genomic approaches to detect G-quadruplexes throughout genomic DNA. In particular, we will discuss the use of engineered small molecules and natural proteins to enable pull-down, ChIP-Seq, ChIP-chip and fluorescence imaging of G-quadruplex structures in cellular DNA. Copyright © 2012 Elsevier Inc. All rights reserved.

Thermodynamics of Methane Adsorption on Copper HKUST-1 at Low Pressure.

PubMed

Wu, Di; Guo, Xiaofeng; Sun, Hui; Navrotsky, Alexandra

2015-07-02

Metal-organic frameworks (MOFs) can be engineered as natural gas storage materials by tuning the pore structures and surface properties. Here we report the direct measurement of CH4 adsorption enthalpy on a paddlewheel MOF (Cu HKUST-1) using gas adsorption calorimetry at 25 °C at low pressures (below 1 bar). In this pressure region, the CH4-CH4 intermolecular interactions are minimized and the energetics solely reflects the CH4-MOF interactions. Our results suggest moderately exothermic physisorption with an enthalpy of -21.1 ± 1.1 kJ/mol CH4 independent of coverage. This calorimetric investigation complements previous computational and crystallographic studies by providing zero coverage enthalpies of CH4 adsorption. The analysis of the new and literature data suggests that in initial stages of adsorption the CH4-HKUST-1 interaction tends to be more sensitive to the pore dimension than to the guest polarizability, suggesting a less specific chemical binding role for the open Cu site.

Student Chemical Engineering Reflective ePortfolios--ChE Student Perceptions of Learning from Reflective ePortfolio Creation

ERIC Educational Resources Information Center

Cherrstrom, Catherine A.; Raisor, Cindy; Fowler, Debra

2015-01-01

Engineering educators and employers value and prioritize communication skills, but developing and assessing such skills in engineering programs is challenging. Reflective ePortfolios provide opportunities to enhance communication skills. The purpose of this three-­year qualitative case study was to investigate the use of reflective ePortfolios in…

Molecularly Engineered Organic-Inorganic Hybrid Perovskite with Multiple Quantum Well Structure for Multicolored Light-Emitting Diodes

PubMed Central

Hu, Hongwei; Salim, Teddy; Chen, Bingbing; Lam, Yeng Ming

2016-01-01

Organic-inorganic hybrid perovskites have the potential to be used as a new class of emitters with tunable emission, high color purity and good ease of fabrication. Recent studies have so far been focused on three-dimensional (3D) perovskites, such as CH3NH3PbBr3 and CH3NH3PbI3 for green and infrared emission. Here, we explore a new series of hybrid perovskite emitters with a general formula of (C4H9NH3)2(CH3NH3)n−1PbnI3n+1 (where n = 1, 2, 3), which possesses a multiple quantum well structure. The quantum well thickness of these materials is adjustable through simple molecular engineering which results in a continuously tunable bandgap and emission spectra. Deep saturated red emission was obtained with a peak external quantum efficiency of 2.29% and a maximum luminance of 214 cd/m2. Green and blue LEDs were also demonstrated through halogen substitutions in these hybrid perovskites. We expect these results to open up the way towards high performance perovskite LEDs through molecular-structure engineering of these perovskite emitters. PMID:27633084

Biocompatible hollow polymeric particles produced by a mild solvent- and template free strategy.

PubMed

Rodríguez-Velázquez, Eustolia; Taboada, Pablo; Alatorre-Meda, Manuel

2017-08-31

Macroscopic hollow polymeric particles are attractive materials for various applications such as surgery, food industry, agriculture, etc. However, protocols reporting their synthesis have hitherto made use of organic solvents and/or sacrificial templates, compromising the encapsulation of different bioactive compounds and the process yield. Here, millimeter-size, hollow polymeric particles were synthesized, for the first time, in a solvent- and template free manner onto superhydrophobic surfaces (SHS). The particles were produced upon assembly and double superficial crosslinking of liquid droplets of DNA and methacrylamide chitosan aqueous solutions (CH:MA), leading to liquid-core particles with a hardened hydrogel shell. The particles displayed appealing physical and biological properties. The millimeter-size hydrogel shell, resulting from the double ionic/covalent crosslinking of CH:MA, endowed the hollow particles with softness to the touch and an outstanding structural stability against manipulation by hand and with forceps. Meanwhile, the liquid DNA core guaranteed a biocompatible cell encapsulation followed by a superior release and proliferation of viable cells, as compared to solid CH:MA particles prepared as a blank. Particles with these characteristics show promise for surgical protocols practiced in Tissue Engineering and Regenerative Medicine, where manipulable and biocompatible synthetic implants are often needed to supply living cells and other sensitive bioactive compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Biocompatible hollow polymeric particles produced by a mild solvent- and template free strategy.

PubMed

Rodríguez-Velázquez, Eustolia; Taboada, Pablo; Alatorre-Meda, Manuel

2017-12-01

Macroscopic hollow polymeric particles are attractive materials for various applications such as surgery, food industry, agriculture, etc. However, protocols reporting their synthesis have hitherto made use of organic solvents and/or sacrificial templates, compromising the encapsulation of different bioactive compounds and the process yield. Here, millimeter-size, hollow polymeric particles were synthesized, for the first time, in a solvent- and template free manner onto superhydrophobic surfaces (SHS). The particles were produced upon assembly and double superficial crosslinking of liquid droplets of DNA and methacrylamide chitosan aqueous solutions (CH:MA), leading to liquid-core particles with a hardened hydrogel shell. The particles displayed appealing physical and biological properties. The millimeter-size hydrogel shell, resulting from the double ionic/covalent crosslinking of CH:MA, endowed the hollow particles with softness to the touch and an outstanding structural stability against manipulation by hand and with forceps. Meanwhile, the liquid DNA core guaranteed a biocompatible cell encapsulation followed by a superior release and proliferation of viable cells, as compared to solid CH:MA particles prepared as a blank. Particles with these characteristics show promise for surgical protocols practiced in Tissue Engineering and Regenerative Medicine, where manipulable and biocompatible synthetic implants are often needed to supply living cells and other sensitive bioactive compounds. Copyright © 2017. Published by Elsevier B.V.

The inevitable journey to being.

PubMed

Russell, Michael J; Nitschke, Wolfgang; Branscomb, Elbert

2013-07-19

Life is evolutionarily the most complex of the emergent symmetry-breaking, macroscopically organized dynamic structures in the Universe. Members of this cascading series of disequilibria-converting systems, or engines in Cottrell's terminology, become ever more complicated-more chemical and less physical-as each engine extracts, exploits and generates ever lower grades of energy and resources in the service of entropy generation. Each one of these engines emerges spontaneously from order created by a particular mother engine or engines, as the disequilibrated potential daughter is driven beyond a critical point. Exothermic serpentinization of ocean crust is life's mother engine. It drives alkaline hydrothermal convection and thereby the spontaneous production of precipitated submarine hydrothermal mounds. Here, the two chemical disequilibria directly causative in the emergence of life spontaneously arose across the mineral precipitate membranes separating the acidulous, nitrate-bearing CO2-rich, Hadean sea from the alkaline and CH4/H2-rich serpentinization-generated effluents. Essential redox gradients-involving hydrothermal CH4 and H2 as electron donors, CO2 and nitrate, nitrite, and ferric iron from the ambient ocean as acceptors-were imposed which functioned as the original 'carbon-fixing engine'. At the same time, a post-critical-point (milli)voltage pH potential (proton concentration gradient) drove the condensation of orthophosphate to produce a high energy currency: 'the pyrophosphatase engine'.

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2007-08-15

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2007-06-15

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2007-09-20

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2006-06-20

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2006-01-18

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2006-08-15

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2006-12-20

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2007-02-15

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

CH-TRU Waste Content Codes (CH-TRUCON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2006-09-15

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

Tripropellant engine study

NASA Technical Reports Server (NTRS)

Wheeler, D. B.

1978-01-01

Engine performance data, combustion gas thermodynamic properties, and turbine gas parameters were determined for various high power cycle engine configurations derived from the space shuttle main engine that will allow sequential burning of LOX/hydrocarbon and LOX/hydrogen fuels. Both stage combustion and gas generator pump power cycles were considered. Engine concepts were formulated for LOX/RP-1, LOX/CH4, and LOX/C3H8 propellants. Flowrates and operating conditions were established for this initial set of engine systems, and the adaptability of the major components of shuttle main engine was investigated.

Molecular Dynamics Simulation of the Crystallizable Fragment of IgG1—Insights for the Design of Fcabs

PubMed Central

Lai, Balder; Hasenhindl, Christoph; Obinger, Christian; Oostenbrink, Chris

2014-01-01

An interesting format in the development of therapeutic monoclonal antibodies uses the crystallizable fragment of IgG1 as starting scaffold. Engineering of its structural loops allows generation of an antigen binding site. However, this might impair the molecule’s conformational stability, which can be overcome by introducing stabilizing point mutations in the CH3 domains. These point mutations often affect the stability and unfolding behavior of both the CH2 and CH3 domains. In order to understand this cross-talk, molecular dynamics simulations of the domains of the Fc fragment of human IgG1 are reported. The structure of human IgG1-Fc obtained from X-ray crystallography is used as a starting point for simulations of the wild-type protein at two different pH values. The stabilizing effect of a single point mutation in the CH3 domain as well as the impact of the hinge region and the glycan tree structure connected to the CH2 domains is investigated. Regions of high local flexibility were identified as potential sites for engineering antigen binding sites. Obtained data are discussed with respect to the available X-ray structure of IgG1-Fc, directed evolution approaches that screen for stability and use of the scaffold IgG1-Fc in the design of antigen binding Fc proteins. PMID:24451126

Reviews and syntheses: Four decades of modeling methane cycling in terrestrial ecosystems

NASA Astrophysics Data System (ADS)

Xu, Xiaofeng; Yuan, Fengming; Hanson, Paul J.; Wullschleger, Stan D.; Thornton, Peter E.; Riley, William J.; Song, Xia; Graham, David E.; Song, Changchun; Tian, Hanqin

2016-06-01

Over the past 4 decades, a number of numerical models have been developed to quantify the magnitude, investigate the spatial and temporal variations, and understand the underlying mechanisms and environmental controls of methane (CH4) fluxes within terrestrial ecosystems. These CH4 models are also used for integrating multi-scale CH4 data, such as laboratory-based incubation and molecular analysis, field observational experiments, remote sensing, and aircraft-based measurements across a variety of terrestrial ecosystems. Here we summarize 40 terrestrial CH4 models to characterize their strengths and weaknesses and to suggest a roadmap for future model improvement and application. Our key findings are that (1) the focus of CH4 models has shifted from theoretical to site- and regional-level applications over the past 4 decades, (2) large discrepancies exist among models in terms of representing CH4 processes and their environmental controls, and (3) significant data-model and model-model mismatches are partially attributed to different representations of landscape characterization and inundation dynamics. Three areas for future improvements and applications of terrestrial CH4 models are that (1) CH4 models should more explicitly represent the mechanisms underlying land-atmosphere CH4 exchange, with an emphasis on improving and validating individual CH4 processes over depth and horizontal space, (2) models should be developed that are capable of simulating CH4 emissions across highly heterogeneous spatial and temporal scales, particularly hot moments and hotspots, and (3) efforts should be invested to develop model benchmarking frameworks that can easily be used for model improvement, evaluation, and integration with data from molecular to global scales. These improvements in CH4 models would be beneficial for the Earth system models and further simulation of climate-carbon cycle feedbacks.

ChE Undergraduate Research Projects in Biomedical Engineering.

ERIC Educational Resources Information Center

Stroeve, Pieter

1981-01-01

Describes an undergraduate research program in biomedical engineering at the State University of New York at Buffalo. Includes goals and faculty comments on the program. Indicates that 58 percent of projects conducted between 1976 and 1980 have been presented at meetings or published. (SK)

78 FR 76114 - 36(b)(1) Arms Sales Notification

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-16

... Proposed Issuance of Letter of Offer Pursuant to Section 36(b)(1) of the Arms Export Control Act, as... Articles or Services under Consideration for Purchase: 14 CH-47D Model Aircraft to include T55-GA-714A Turbine Engines, 2 per aircraft (14 ac x 2 = 28 engines) 5 T55-GA-714A Turbine Engines to be used as...

Chemical Engineering Data Analysis Made Easy with DataFit

ERIC Educational Resources Information Center

Brenner, James R.

2006-01-01

The outline for half of a one-credit-hour course in analysis of chemical engineering data is presented, along with a range of typical problems encountered later on in the chemical engineering curriculum that can be used to reinforce the data analysis skills learned in the course. This mini course allows students to be exposed to a variety of ChE…

CH-TRU Waste Content Codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington TRU Solutions LLC

2008-01-16

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container.more » Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 of the CH-TRU Payload Appendices. For shipments to WIPP from Los Alamos National Laboratory (LANL), Nevada Test Site, and Rocky Flats Environmental Technology Site, a 20-day shipping period is applicable. Table 2B provides a summary of approved content codes and corresponding shipping categories for "Close-Proximity Shipments" (20-day shipping period). For shipments implementing the controls specified in the CH-TRAMPAC and Appendix 3.6 of the CH-TRU Payload Appendices, a 10-day shipping period is applicable. Table 2C provides a summary of approved content codes and corresponding shipping categories for "Controlled Shipments" (10-day shipping period).« less

Four decades of modeling methane cycling in terrestrial ecosystems: Where we are heading?

NASA Astrophysics Data System (ADS)

Xu, X.; Yuan, F.; Hanson, P. J.; Wullschleger, S. D.; Thornton, P. E.; Tian, H.; Riley, W. J.; Song, X.; Graham, D. E.; Song, C.

2015-12-01

A modeling approach to methane (CH4) is widely used to quantify the budget, investigate spatial and temporal variabilities, and understand the mechanistic processes and environmental controls on CH4 fluxes across spatial and temporal scales. Moreover, CH4 models are an important tool for integrating CH4 data from multiple sources, such as laboratory-based incubation and molecular analysis, field observational experiments, remote sensing, and aircraft-based measurements across a variety of terrestrial ecosystems. We reviewed 39 terrestrial CH4 models to characterize their strengths and weaknesses and to design a roadmap for future model improvement and application. We found that: (1) the focus of CH4 models have been shifted from theoretical to site- to regional-level application over the past four decades, expressed as dramatic increases in CH4 model development on regional budget quantification; (2) large discrepancies exist among models in terms of representing CH4 processes and their environmental controls; (3) significant data-model and model-model mismatches are partially attributed to different representations of wetland characterization and inundation dynamics. Three efforts should be paid special attention for future improvements and applications of fully mechanistic CH4 models: (1) CH4 models should be improved to represent the mechanisms underlying land-atmosphere CH4 exchange, with emphasis on improving and validating individual CH4 processes over depth and horizontal space; (2) models should be developed that are capable of simulating CH4 fluxes across space and time (particularly hot moments and hot spots); (3) efforts should be invested to develop model benchmarking frameworks that can easily be used for model improvement, evaluation, and integration with data from molecular to global scales. A newly developed microbial functional group-based CH4 model (CLM-Microbe) was further used to demonstrate the features of mechanistic representation and integration with multiple source of observational datasets.

Tripropellant engine study

NASA Technical Reports Server (NTRS)

Wheeler, D. B.; Kirby, F. M.

1978-01-01

The potential for converting the space shuttle main engine (SSME) to a dual-fuel, dual-mode engine using LOX/hydrocarbon propellants in mode 1 and LOX/H2 in mode 2 was examined. Various engine system concepts were formulated that included staged combustion and gas generator turbine power cycles, and LOX/RP-1, LOX/CH4, and LOX/C3H8 mode 1 propellants. Both oxidizer and fuel regenerative cooling were considered. All of the SSME major components were examined to determine their adaptability to the candidate dual-fuel engines.

How Much Safety Do We Need in ChE Education?

ERIC Educational Resources Information Center

Mewis, Jan

1984-01-01

Discusses aims, objectives, and content of a safety course for chemical engineering students. Course emphasizes awareness of hazards, basic concepts and principles of safety engineering, and the ability to recognize, assess, and remedy specific risks occurring in chemical plants. Course implementation is also discussed. (JN)

78 FR 56171 - Heavy-Duty Engine and Vehicle and Nonroad Technical Amendments

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-12

...-0152; FRL 9900-11-OAR] RIN 2060-AR48; 2127-AL31 Heavy-Duty Engine and Vehicle and Nonroad Technical... emission standards for CO2, CH4, and N2O for heavy-duty vehicles at or below 14,000 pounds GVWR [Corrected...

Estimated Emissions from the Prime-Movers of Unconventional Natural Gas Well Development Using Recently Collected In-Use Data in the United States.

PubMed

Johnson, Derek; Heltzel, Robert; Nix, Andrew; Darzi, Mahdi; Oliver, Dakota

2018-05-01

Natural gas from shale plays dominates new production and growth. However, unconventional well development is an energy intensive process. The prime movers, which include over-the-road service trucks, horizontal drilling rigs, and hydraulic fracturing pumps, are predominately powered by diesel engines that impact air quality. Instead of relying on certification data or outdated emission factors, this model uses new in-use emissions and activity data combined with historical literature to develop a national emissions inventory. For the diesel only case, hydraulic fracturing engines produced the most NO x emissions, while drilling engines produced the most CO emissions, and truck engines produced the most THC emissions. By implementing dual-fuel and dedicated natural gas engines, total fuel energy consumed, CO 2 , CO, THC, and CH 4 emissions would increase, while NO x emissions, diesel fuel consumption, and fuel costs would decrease. Dedicated natural gas engines offered significant reductions in NO x emissions. Additional scenarios examined extreme cases of full fleet conversions. While deep market penetrations could reduce fuel costs, both technologies could significantly increase CH 4 emissions. While this model is based on a small sample size of engine configurations, data were collected during real in-use activity and is representative of real world activity.

Two-wavelength single laser CH and CH(4) imaging in a lifted turbulent diffusion flame.

PubMed

Namazian, M; Schmitt, R L; Long, M B

1988-09-01

A new technique has been developed which allows simultaneous 2-D mapping of CH and CH 4 in a turbulent methane flame. A flashlamp-pumped dye laser using two back mirrors produces output at 431.5 and 444 nm simultaneously. The 431.5-nm line is used to excite the (0, 0) band of the A(2)Delta-X(2)Pi system of CH, and the fluorescence of the (0, 1) transition is observed at 489 nm. Coincidentally, the spontaneous Raman scattering from CH(4) also occurs near 489 nm for a 431.5-nm excitation. To separate the CH(4) and CH contributions, the 444-nm line is used to produce a spontaneous Raman signal from CH(4) that is spectrally separated from the CH fluorescence. Subtraction of the signals generated by the 431.5- and 444-nm wavelength beams yields separate measurements of CH(4) and CH. Raman-scattered light records the instantaneous distribution of the fuel, and simultaneously the CH fluorescence indicates the location of the flame zone. The resulting composite images provide important insight on the interrelationship between fuel-air mixing and subsequent combustion.M. Namazian is with Altex Technologies Corporation, 109 Via De Tesoros, Los Gatos, California 95030; R. L. Schmitt is with Sandia National Laboratories, Combustion Research Facility, Livermore, California 94550; and M. B. Long is with Yale University, Department of Mechanical Engineering, New Haven, Connecticut 06520.

Optimized spectroscopic scheme for enhanced precision CO measurements with applications to urban source attribution

NASA Astrophysics Data System (ADS)

Nottrott, A.; Hoffnagle, J.; Farinas, A.; Rella, C.

2014-12-01

Carbon monoxide (CO) is an urban pollutant generated by internal combustion engines which contributes to the formation of ground level ozone (smog). CO is also an excellent tracer for emissions from mobile combustion sources. In this work we present an optimized spectroscopic sampling scheme that enables enhanced precision CO measurements. The scheme was implemented on the Picarro G2401 Cavity Ring-Down Spectroscopy (CRDS) analyzer which measures CO2, CO, CH4 and H2O at 0.2 Hz. The optimized scheme improved the raw precision of CO measurements by 40% from 5 ppb to 3 ppb. Correlations of measured CO2, CO, CH4 and H2O from an urban tower were partitioned by wind direction and combined with a concentration footprint model for source attribution. The application of a concentration footprint for source attribution has several advantages. The upwind extent of the concentration footprint for a given sensor is much larger than the flux footprint. Measurements of mean concentration at the sensor location can be used to estimate source strength from a concentration footprint, while measurements of the vertical concentration flux are necessary to determine source strength from the flux footprint. Direct measurement of vertical concentration flux requires high frequency temporal sampling and increases the cost and complexity of the measurement system.

A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity.

PubMed

Leung, Siu-Fung; Ho, Kang-Ting; Kung, Po-Kai; Hsiao, Vincent K S; Alshareef, Husam N; Wang, Zhong Lin; He, Jr-Hau

2018-02-01

Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH 3 NH 3 PBI 3 ) perovskite is demonstrated. Such a self-powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high-quality CH 3 NH 3 PBI 3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 10 13 Jones. In the self-powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW -1 cm -2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self-powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real-world sensing capability, suggests a new direction for next-generation optical communications, sensing, and imaging applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR 86.1818-12 - Greenhouse gas emission standards for light-duty vehicles, light-duty trucks, and medium-duty...

Code of Federal Regulations, 2014 CFR

2014-07-01

...-equivalent debits for a test group using an alternative N2O or CH4 standard; GWP = 25 if calculating CH4...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light-Duty Trucks, and Complete Otto...

Engine Oils with a New Composition of Additives

DTIC Science & Technology

A lubricant additive composition IKhP (2.6% BFK, a Ba salt of a CH2O- alkylphenol condensation product; 1.4% SB-3, a Ba sulfonate; 1.2% IN-KhP-21, a...Ba salt of a CH2O-NH3- alkylphenol condensation product; 0.005% PMS-200A; and 0. 5% AzNII) is discussed in relationship to its use as an automobile oil

Optogenetic Light Crafting Tools for the Control of Cardiac Arrhythmias.

PubMed

Richter, Claudia; Christoph, Jan; Lehnart, Stephan E; Luther, Stefan

2016-01-01

The control of spatiotemporal dynamics in biological systems is a fundamental problem in nonlinear sciences and has important applications in engineering and medicine. Optogenetic tools combined with advanced optical technologies provide unique opportunities to develop and validate novel approaches to control spatiotemporal complexity in neuronal and cardiac systems. Understanding of the mechanisms and instabilities underlying the onset, perpetuation, and control of cardiac arrhythmias will enable the development and translation of novel therapeutic approaches. Here we describe in detail the preparation and optical mapping of transgenic channelrhodopsin-2 (ChR2) mouse hearts, cardiac cell cultures, and the optical setup for photostimulation using digital light processing.

Catalytic and electrochemical behaviour of solid oxide fuel cell operated with simulated-biogas mixtures

NASA Astrophysics Data System (ADS)

Dang-Long, T.; Quang-Tuyen, T.; Shiratori, Y.

2016-06-01

Being produced from organic matters of wastes (bio-wastes) through a fermentation process, biogas mainly composed of CH4 and CO2 and can be considered as a secondary energy carrier derived from solar energy. To generate electricity from biogas through the electrochemical process in fuel cells is a state-of-the-art technology possessing higher energy conversion efficiency without harmful emissions compared to combustion process in heat engines. Getting benefits from high operating temperature such as direct internal reforming ability and activation of electrochemical reactions to increase overall system efficiency, solid oxide fuel cell (SOFC) system operated with biogas becomes a promising candidate for distributed power generator for rural applications leading to reductions of environmental issues caused by greenhouse effects and bio-wastes. CO2 reforming of CH4 and electrochemical oxidation of the produced syngas (H2-CO mixture) are two main reaction processes within porous anode material of SOFC. Here catalytic and electrochemical behavior of Ni-ScSZ (scandia stabilized-zirconia) anode in the feed of CH4-CO2 mixtures as simulated-biogas at 800 °C were evaluated. The results showed that CO2 had strong influences on both reaction processes. The increase in CO2 partial pressure resulted in the decrease in anode overvoltage, although open-circuit voltage was dropped. Besides that, the simulation result based on a power-law model for equimolar CH4-CO2 mixture revealed that coking hazard could be suppressed along the fuel flow channel in both open-circuit and closed-circuit conditions.

Laboratory estimates of trace gas emissions following surface application and injection of cattle slurry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flessa, H.; Beese, F.

2000-02-01

Applying cattle slurry to soil may induce emissions of the greenhouse gases N{sub 2}O and CH{sub 4}. Their objective was to determine the effects of different application techniques (surface application and slit injection) of cattle (Bostaurus) slurry on the decomposition of slurry organic matter and the emissions of N{sub 2}O and CH{sub 4}. The effects of slurry application (43.6 m{sup 3} ha{sup {minus}1}) were studied for 9 wk under controlled laboratory conditions using a soil microcosm system with automated monitoring of the CO{sub 2}, N{sub 2}O, and CH{sub 4} fluxes. The soil used was a silty loam (Ap horizon ofmore » a cambisol) with a constant water-filled pore space of 67% during the experiment. About 38% of the organic matter applied with the slurry was decomposed within 9 wk. Production of CO{sub 2} was not affected by the application technique. Emissions of N{sub 2}O and CH{sub 4} from the injected slurry were significantly higher than from the surface-applied slurry, probably because of restricted aeration at the injected-slurry treatment. Total N{sub 2}O-N emissions were 0.2% (surface application) and 3.3% (slit injection) of the slurry N added. Methane emission occurred only during the first few days following application. The total net flux of CH{sub 4}-C for 2 wk was {minus}12 g ha{sup {minus}1} for the control (CH{sub 4} uptake), 2 g ha{sup {minus}1} for the surface-applied slurry, and 39 g ha{sup {minus}1} for the injected slurry. Slurry injection, which is recommended to reduce NH{sub 3} volatilization, appears to increase emissions of the greenhouse gases N{sub 2}O and CH{sub 4} from the fertilized fields.« less

Biological effects of 2,4-pentadiene-1-ol.

PubMed

Benesová, O; Sprincl, L; Ulbrich, K; Obereigner, B; Drobník, J; Kálal, J; Kopecek

1977-07-01

The biological effects of 2,4-pentadiene-1-ol (CH2 = CH--CH = CH--CH2--OH) the starting monomer in the preparation of a biocompatible polymer were studied. The experiments in rats revealed both a high local (oedema, necrosis) and systemic toxicity. Within 5-10 min after dermal application of 0.2 ml the compound evoked intensive hyperaemia of acral parts (ears, snout, paws) and induced severe breathing difficulties which led to death in half of the animals after a single administration. The most evident macroscopic and microscopic pathologic changes were found in the place of application and in the lungs (haemorrhage in alveolae). Both clinical and histological findings indicated that the toxicity is due to an increased permeability of capillaries.

Computational Studies Of Chemical Reactions: The Hnc-Hcn And Ch[subscript3]Nc-Ch[subscript3]Cn Isomerizations

ERIC Educational Resources Information Center

Halpern, Arthur M.

2006-01-01

The application of computational methods to the isomerization of hydrogen isocyanide to hydrogen cyanide, HNC-HCN is described. The logical extension to the exercise is presented to the isomerization of the methyl-substituted compounds, methylisocyanide and methylcyanide, Ch[subscript 3]NC-CH[subscript3]CN.

ChIP-nexus: a novel ChIP-exo protocol for improved detection of in vivo transcription factor binding footprints

PubMed Central

He, Qiye; Johnston, Jeff; Zeitlinger, Julia

2014-01-01

Understanding how eukaryotic enhancers are bound and regulated by specific combinations of transcription factors is still a major challenge. To better map transcription factor binding genome-wide at nucleotide resolution in vivo, we have developed a robust ChIP-exo protocol called ChIP experiments with nucleotide resolution through exonuclease, unique barcode and single ligation (ChIP-nexus), which utilizes an efficient DNA self-circularization step during library preparation. Application of ChIP-nexus to four proteins—human TBP and Drosophila NFkB, Twist and Max— demonstrates that it outperforms existing ChIP protocols in resolution and specificity, pinpoints relevant binding sites within enhancers containing multiple binding motifs and allows the analysis of in vivo binding specificities. Notably, we show that Max frequently interacts with DNA sequences next to its motif, and that this binding pattern correlates with local DNA sequence features such as DNA shape. ChIP-nexus will be broadly applicable to studying in vivo transcription factor binding specificity and its relationship to cis-regulatory changes in humans and model organisms. PMID:25751057

Chitosan-PLGA polymer blends as coatings for hydroxyapatite nanoparticles and their effect on antimicrobial properties, osteoconductivity and regeneration of osseous tissues

PubMed Central

Ignjatović, Nenad; Wu, Victoria; Ajduković, Zorica; Mihajilov-Krstev, Tatjana; Uskoković, Vuk; Uskoković, Dragan

2016-01-01

Composite biomaterials comprising nanostructured hydroxyapatite (HAp) have an enormous potential for natural bone tissue reparation, filling and augmentation. Chitosan (Ch) as a naturally derived polymer has many physicochemical and biological properties that make it an attractive material for use in bone tissue engineering. On the other hand, poly-D,L-lactide-co-glycolide (PLGA) is a synthetic polymer with a long history of use in sustained drug delivery and tissue engineering. However, while chitosan can disrupt the cell membrane integrity and may induce blood thrombosis, PLGA releases acidic byproducts that may cause tissue inflammation and interfere with the healing process. One of the strategies to improve the biocompatibility of Ch and PLGA is to combine them with compounds that exhibit complementary properties. In this study we present the synthesis and characterization, as well as in vitro and in vivo analyses of a nanoparticulate form of HAp coated with two different polymeric systems: (a) Ch and (b) a Ch-PLGA polymer blend. Solvent/non-solvent precipitation and freeze-drying were used for synthesis and processing, respectively, whereas thermogravimetry coupled with mass spectrometry was used for phase identification purposes in the coating process. HAp/Ch composite particles exhibited the highest antimicrobial activity against all four microbial strains tested in this work, but after the reconstruction of the bone defect they also caused inflammatory reactions in the newly formed tissue where the defect had lain. Coating HAp with a polymeric blend composed of Ch and PLGA led to a decrease in the reactivity and antimicrobial activity of the composite particles, but also to an increase in the quality of the newly formed bone tissue in the reconstructed defect area. PMID:26706541

Using ChEMBL web services for building applications and data processing workflows relevant to drug discovery.

PubMed

Nowotka, Michał M; Gaulton, Anna; Mendez, David; Bento, A Patricia; Hersey, Anne; Leach, Andrew

2017-08-01

ChEMBL is a manually curated database of bioactivity data on small drug-like molecules, used by drug discovery scientists. Among many access methods, a REST API provides programmatic access, allowing the remote retrieval of ChEMBL data and its integration into other applications. This approach allows scientists to move from a world where they go to the ChEMBL web site to search for relevant data, to one where ChEMBL data can be simply integrated into their everyday tools and work environment. Areas covered: This review highlights some of the audiences who may benefit from using the ChEMBL API, and the goals they can address, through the description of several use cases. The examples cover a team communication tool (Slack), a data analytics platform (KNIME), batch job management software (Luigi) and Rich Internet Applications. Expert opinion: The advent of web technologies, cloud computing and micro services oriented architectures have made REST APIs an essential ingredient of modern software development models. The widespread availability of tools consuming RESTful resources have made them useful for many groups of users. The ChEMBL API is a valuable resource of drug discovery bioactivity data for professional chemists, chemistry students, data scientists, scientific and web developers.

Kinetic study on anaerobic oxidation of methane coupled to denitrification.

PubMed

Yu, Hou; Kashima, Hiroyuki; Regan, John M; Hussain, Abid; Elbeshbishy, Elsayed; Lee, Hyung-Sool

2017-09-01

Monod kinetic parameters provide information required for kinetic analysis of anaerobic oxidation of methane coupled to denitrification (AOM-D). This information is critical for engineering AOM-D processes in wastewater treatment facilities. We first experimentally determined Monod kinetic parameters for an AOM-D enriched culture and obtained the following values: maximum specific growth rate (μ max ) 0.121/d, maximum substrate-utilization rate (q max ) 28.8mmol CH 4 /g cells-d, half maximum-rate substrate concentration (K s ) 83μΜ CH 4 , growth yield (Y) 4.76gcells/mol CH 4 , decay coefficient (b) 0.031/d, and threshold substrate concentration (S min ) 28.8μM CH 4 . Clone library analysis of 16S rRNA and mcrA gene fragments suggested that AOM-D reactions might have occurred via the syntrophic interaction between denitrifying bacteria (e.g., Ignavibacterium, Acidovorax, and Pseudomonas spp.) and hydrogenotrophic methanogens (Methanobacterium spp.), supporting reverse methanogenesis-dependent AOM-D in our culture. High μ max and q max , and low K s for the AOM-D enrichment imply that AOM-D could play a significant role in mitigating atmospheric methane efflux. In addition, these high kinetic features suggest that engineered AOM-D systems may provide a sustainable alternative to nitrogen removal in wastewater treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of a transgenic tobacco plant for phytoremediation of methylmercury pollution.

PubMed

Nagata, Takeshi; Morita, Hirofumi; Akizawa, Toshifumi; Pan-Hou, Hidemitsu

2010-06-01

To develop the potential of plant for phytoremediation of methylmercury pollution, a genetically engineered tobacco plant that coexpresses organomercurial lyase (MerB) with the ppk-specified polyphosphate (polyP) and merT-encoding mercury transporter was constructed by integrating a bacterial merB gene into ppk/merT-transgenic tobacco. A large number of independent transgenic tobaccos was obtained, in some of which the merB gene was stably integrated in the plant genome and substantially translated to the expected MerB enzyme in the transgenic tobacco. The ppk/merT/merB-transgenic tobacco callus showed more resistance to methylmercury (CH3Hg+) and accumulated more mercury from CH3Hg+-containing medium than the ppk/merT-transgenic and wild-type progenitors. These results suggest that the MerB enzyme encoded by merB degraded the incorporated CH3Hg+ to Hg2+, which then accumulated as a less toxic Hg-polyP complex in the tobacco cells. Phytoremediation of CH3Hg+ and Hg2+ in the environment with this engineered ppk/merT/merB-transgenic plant, which prevents the release mercury vapor (Hg0) into the atmosphere in addition to generating potentially recyclable mercury-rich plant residues, is believed to be more acceptable to the public than other competing technologies, including phytovolatilization.

Reviews and syntheses: Four decades of modeling methane cycling in terrestrial ecosystems

DOE PAGES

Xu, Xiaofeng; Yuan, Fengming; Hanson, Paul J.; ...

2016-01-28

A number of numerical models have been developed to quantify the magnitude, over the past 4 decades, such that we have investigated the spatial and temporal variations, and understand the underlying mechanisms and environmental controls of methane (CH 4) fluxes within terrestrial ecosystems. These CH 4 models are also used for integrating multi-scale CH 4 data, such as laboratory-based incubation and molecular analysis, field observational experiments, remote sensing, and aircraft-based measurements across a variety of terrestrial ecosystems. Here we summarize 40 terrestrial CH 4 models to characterize their strengths and weaknesses and to suggest a roadmap for future model improvementmore » and application. Our key findings are that (1) the focus of CH 4 models has shifted from theoretical to site- and regional-level applications over the past 4 decades, (2) large discrepancies exist among models in terms of representing CH 4 processes and their environmental controls, and (3) significant data–model and model–model mismatches are partially attributed to different representations of landscape characterization and inundation dynamics. Furthermore three areas for future improvements and applications of terrestrial CH 4 models are that (1) CH 4 models should more explicitly represent the mechanisms underlying land–atmosphere CH 4 exchange, with an emphasis on improving and validating individual CH 4 processes over depth and horizontal space, (2) models should be developed that are capable of simulating CH 4 emissions across highly heterogeneous spatial and temporal scales, particularly hot moments and hotspots, and (3) efforts should be invested to develop model benchmarking frameworks that can easily be used for model improvement, evaluation, and integration with data from molecular to global scales. Finally, these improvements in CH 4 models would be beneficial for the Earth system models and further simulation of climate–carbon cycle feedbacks.« less

Influence of methane in CO2 transport and storage for CCS technology.

PubMed

Blanco, Sofía T; Rivas, Clara; Fernández, Javier; Artal, Manuela; Velasco, Inmaculada

2012-12-04

CO(2) Capture and Storage (CCS) is a good strategy to mitigate levels of atmospheric greenhouse gases. The type and quantity of impurities influence the properties and behavior of the anthropogenic CO(2), and so must be considered in the design and operation of CCS technology facilities. Their study is necessary for CO(2) transport and storage, and to develop theoretical models for specific engineering applications to CCS technology. In this work we determined the influence of CH(4), an important impurity of anthropogenic CO(2), within different steps of CCS technology: transport, injection, and geological storage. For this, we obtained new pressure-density-temperature (PρT) and vapor-liquid equilibrium (VLE) experimental data for six CO(2) + CH(4) mixtures at compositions which represent emissions from the main sources in the European Union and United States. The P and T ranges studied are within those estimated for CO(2) pipelines and geological storage sites. From these data we evaluated the minimal pressures for transport, regarding the density and pipeline's capacity requirements, and values for the solubility parameter of the mixtures, a factor which governs the solubility of substances present in the reservoir before injection. We concluded that the presence of CH(4) reduces the storage capacity and increases the buoyancy of the CO(2) plume, which diminishes the efficiency of solubility and residual trapping of CO(2), and reduces the injectivity into geological formations.

11. Photographic copy of photograph, photographer unknown, 2 July 1938 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Photographic copy of photograph, photographer unknown, 2 July 1938 (original print located at U.S. Bureau of Reclamation Upper Columbia Area Office, Yakima, Washington). "Inspecting concrete on upstream face of Keechelus Dam spillway. Joseph Jacobs, consulting engineer; M.B. Lemon, Gatetender; Paul Taylor, assistant engineer; and C.H. Paul, consulting engineer." - Keechelus Dam, Spillway, Yakim River, 10 miles northwest of Easton, Easton, Kittitas County, WA

The inevitable journey to being

PubMed Central

Russell, Michael J.; Nitschke, Wolfgang; Branscomb, Elbert

2013-01-01

Life is evolutionarily the most complex of the emergent symmetry-breaking, macroscopically organized dynamic structures in the Universe. Members of this cascading series of disequilibria-converting systems, or engines in Cottrell's terminology, become ever more complicated—more chemical and less physical—as each engine extracts, exploits and generates ever lower grades of energy and resources in the service of entropy generation. Each one of these engines emerges spontaneously from order created by a particular mother engine or engines, as the disequilibrated potential daughter is driven beyond a critical point. Exothermic serpentinization of ocean crust is life's mother engine. It drives alkaline hydrothermal convection and thereby the spontaneous production of precipitated submarine hydrothermal mounds. Here, the two chemical disequilibria directly causative in the emergence of life spontaneously arose across the mineral precipitate membranes separating the acidulous, nitrate-bearing CO2-rich, Hadean sea from the alkaline and CH4/H2-rich serpentinization-generated effluents. Essential redox gradients—involving hydrothermal CH4 and H2 as electron donors, CO2 and nitrate, nitrite, and ferric iron from the ambient ocean as acceptors—were imposed which functioned as the original ‘carbon-fixing engine’. At the same time, a post-critical-point (milli)voltage pH potential (proton concentration gradient) drove the condensation of orthophosphate to produce a high energy currency: ‘the pyrophosphatase engine’. PMID:23754808

Thermal decomposition of ethanol. 4. Ab initio chemical kinetics for reactions of H atoms with CH3CH2O and CH3CHOH radicals.

PubMed

Xu, Z F; Xu, Kun; Lin, M C

2011-04-21

The potential energy surfaces of H-atom reactions with CH(3)CH(2)O and CH(3)CHOH, two major radicals in the decomposition and oxidation of ethanol, have been studied at the CCSD(T)/6-311+G(3df,2p) level of theory with geometric optimization carried out at the BH&HLYP/6-311+G(3df,2p) level. The direct hydrogen abstraction channels and the indirect association/decomposition channels from the chemically activated ethanol molecule have been considered for both reactions. The rate constants for both reactions have been calculated at 100-3000 K and 10(-4) Torr to 10(3) atm Ar pressure by microcanonical VTST/RRKM theory with master equation solution for all accessible product channels. The results show that the major product channel of the CH(3)CH(2)O + H reaction is CH(3) + CH(2)OH under atmospheric pressure conditions. Only at high pressure and low temperature, the rate constant for CH(3)CH(2)OH formation by collisonal deactivation becomes dominant. For CH(3)CHOH + H, there are three major product channels; at high temperatures, CH(3)+CH(2)OH production predominates at low pressures (P < 100 Torr), while the formation of CH(3)CH(2)OH by collisional deactivation becomes competitive at high pressures and low temperatures (T < 500 K). At high temperatures, the direct hydrogen abstraction reaction producing CH(2)CHOH + H(2) becomes dominant. Rate constants for all accessible product channels in both systems have been predicted and tabulated for modeling applications. The predicted value for CH(3)CHOH + H at 295 K and 1 Torr pressure agrees closely with available experimental data. For practical modeling applications, the rate constants for the thermal unimolecular decomposition of ethanol giving key accessible products have been predicted; those for the two major product channels taking place by dehydration and C-C breaking agree closely with available literature data.

Response of CH4 emissions to straw and biochar applications in double-rice cropping systems: Insights from observations and modeling.

PubMed

Chen, Dan; Wang, Cong; Shen, Jianlin; Li, Yong; Wu, Jinshui

2018-04-01

Paddy soil plays an essential role in contributing to the emission of methane (CH 4 ), a potent greenhouse gas, to the atmosphere. This study aimed to demonstrate the effects of straw incorporation and straw-derived biochar amendment on CH 4 emissions from double-rice cropping fields and to explore their potential mechanisms based on in-situ field measurements conducted for a period of three years (2012-2014) and model analysis. The results showed that the improved soil aeration due to biochar amendment resulted in low CH 4 emissions and that sufficient substrate carbon availability in straw amendment treatments caused high CH 4 emissions. The newly developed CH 4 emission module for the water and nitrogen management model (WNMM), a process-based biophysical model, performed well when simulating both daily CH 4 fluxes and the annual cumulative CH 4 emissions under straw incorporation and biochar amendment. Results of our study indicate that the model has a great potential for upscaling and could benefit mechanism analyses about the factors regulating CH 4 emissions. Application of biochar into paddy fields provides a great opportunity to reduce CH 4 emissions, and the decrease in CH 4 emissions following biochar amendment with repeated crop cycles would sustain for a prolonged period. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bio-inspired voltage-dependent calcium channel blockers.

PubMed

Yang, Tingting; He, Lin-Ling; Chen, Ming; Fang, Kun; Colecraft, Henry M

2013-01-01

Ca(2+) influx via voltage-dependent CaV1/CaV2 channels couples electrical signals to biological responses in excitable cells. CaV1/CaV2 channel blockers have broad biotechnological and therapeutic applications. Here we report a general method for developing novel genetically encoded calcium channel blockers inspired by Rem, a small G-protein that constitutively inhibits CaV1/CaV2 channels. We show that diverse cytosolic proteins (CaVβ, 14-3-3, calmodulin and CaMKII) that bind pore-forming α1-subunits can be converted into calcium channel blockers with tunable selectivity, kinetics and potency, simply by anchoring them to the plasma membrane. We term this method 'channel inactivation induced by membrane-tethering of an associated protein' (ChIMP). ChIMP is potentially extendable to small-molecule drug discovery, as engineering FK506-binding protein into intracellular sites within CaV1.2-α1C permits heterodimerization-initiated channel inhibition with rapamycin. The results reveal a universal method for developing novel calcium channel blockers that may be extended to develop probes for a broad cohort of unrelated ion channels.

Band gap engineering of hydrogenated amorphous carbon thin films for solar cell application

NASA Astrophysics Data System (ADS)

Dwivedi, Neeraj; Kumar, Sushil; Dayal, Saurabh; Rauthan, C. M. S.; Panwar, O. S.; Malik, Hitendra K.

2012-10-01

In this work, self bias variation, nitrogen introduction and oxygen plasma (OP) treatment approaches have been used for tailoring the band gap of hydrogenated amorphous carbon (a-C:H) thin films. The band gap of a-C:H and modified a- C:H films is varied in the range from 1.25 eV to 3.45 eV, which is found to be nearly equal to the full solar spectrum (1 eV- 3.5 eV). Hence, such a-C:H and modified a-C:H films are found to be potential candidate for the development of full spectrum solar cells. Besides this, computer aided simulation with considering variable band gap a-C:H and modified a- C:H films as window layer for amorphous silicon p-i-n solar cells is also performed by AFORS-HET software and maximum efficiency as ~14 % is realized. Since a-C:H is hard material, hence a-C:H and modified a-C:H films as window layer may avoid the use of additional hard and protective coating particularly in n-i-p configuration.

A Modular Approach to Integrating Biofuels Education into ChE Curriculum Part I--Learning Materials

ERIC Educational Resources Information Center

He, Q. Peter; Wang, Jin; Zhang, Rong; Johnson, Donald; Knight, Andrew; Polala, Ravali

2016-01-01

In view of potential demand for skilled engineers and competent researchers in the biofuels field, we have identified a significant gap between advanced biofuels research and undergraduate biofuels education in chemical engineering. To help bridge this gap, we created educational materials that systematically integrate biofuels technologies into…

A Project-based Spiral Curriculum for Introductory Courses in ChE: Part 2. Implementation.

ERIC Educational Resources Information Center

Dixon, Anthony G.; Clark, William M.; DiBiasio, David

2000-01-01

Reports the development, delivery, and assessment of a project-based spiral curriculum for the first sequence chemical engineering courses. Technical proficiency of students under the spiral curriculum was equal to or better than that of students under a traditional curriculum. Attitudes toward chemical engineering and teamwork were better, and…

40 CFR 86.513 - Fuel and engine lubricant specifications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.513 Fuel and engine lubricant... of § 86.513—Gasoline Test Fuel Specifications Item Value Procedure 1 Distillation Range: 1. Initial... of § 86.513—Natural Gas Test Fuel Specifications Item Value 1 Methane, CH4 Minimum, 89.0 mole percent...

CRITERIA POLLUTANT EMISSIONS FROM INTERNAL COMBUSTION ENGINES IN THE NATURAL GAS INDUSTRY VOLUME II. APPENDICES A-I

EPA Science Inventory

The report summarizes emission factors for criteria pollutants (NOx, CO, CH4, C2H6, THC, NMHC, and NMEHC) from stationary internal combustion engines and gas turbines used in the natural gas industry. The emission factors were calculated from test results from five test campaigns...

CRITERIA POLLUTANT EMISSIONS FROM INTERNAL COMBUSTION ENGINES IN THE NATURAL GAS INDUSTRY VOLUME 1. TECHNICAL REPORT

EPA Science Inventory

The report summarizes emission factors for criteria pollutants (NOx, CO, CH4, C2H6, THC, NMHC, and NMEHC) from stationary internal combustion engines and gas turbines used in the natural gas industry. The emission factors were calculated from test results from five test campaigns...

Incorporating Computer-Aided Software in the Undergraduate Chemical Engineering Core Courses

ERIC Educational Resources Information Center

Alnaizy, Raafat; Abdel-Jabbar, Nabil; Ibrahim, Taleb H.; Husseini, Ghaleb A.

2014-01-01

Introductions of computer-aided software and simulators are implemented during the sophomore-year of the chemical engineering (ChE) curriculum at the American University of Sharjah (AUS). Our faculty concurs that software integration within the curriculum is beneficial to our students, as evidenced by the positive feedback received from industry…

Purification of nanogram-range immunoprecipitated DNA in ChIP-seq application.

PubMed

Zhong, Jian; Ye, Zhenqing; Lenz, Samuel W; Clark, Chad R; Bharucha, Adil; Farrugia, Gianrico; Robertson, Keith D; Zhang, Zhiguo; Ordog, Tamas; Lee, Jeong-Heon

2017-12-21

Chromatin immunoprecipitation-sequencing (ChIP-seq) is a widely used epigenetic approach for investigating genome-wide protein-DNA interactions in cells and tissues. The approach has been relatively well established but several key steps still require further improvement. As a part of the procedure, immnoprecipitated DNA must undergo purification and library preparation for subsequent high-throughput sequencing. Current ChIP protocols typically yield nanogram quantities of immunoprecipitated DNA mainly depending on the target of interest and starting chromatin input amount. However, little information exists on the performance of reagents used for the purification of such minute amounts of immunoprecipitated DNA in ChIP elution buffer and their effects on ChIP-seq data. Here, we compared DNA recovery, library preparation efficiency, and ChIP-seq results obtained with several commercial DNA purification reagents applied to 1 ng ChIP DNA and also investigated the impact of conditions under which ChIP DNA is stored. We compared DNA recovery of ten commercial DNA purification reagents and phenol/chloroform extraction from 1 to 50 ng of immunopreciptated DNA in ChIP elution buffer. The recovery yield was significantly different with 1 ng of DNA while similar in higher DNA amounts. We also observed that the low nanogram range of purified DNA is prone to loss during storage depending on the type of polypropylene tube used. The immunoprecipitated DNA equivalent to 1 ng of purified DNA was subject to DNA purification and library preparation to evaluate the performance of four better performing purification reagents in ChIP-seq applications. Quantification of library DNAs indicated the selected purification kits have a negligible impact on the efficiency of library preparation. The resulting ChIP-seq data were comparable with the dataset generated by ENCODE consortium and were highly correlated between the data from different purification reagents. This study provides comparative data on commercial DNA purification reagents applied to nanogram-range immunopreciptated ChIP DNA and evidence for the importance of storage conditions of low nanogram-range purified DNA. We verified consistent high performance of a subset of the tested reagents. These results will facilitate the improvement of ChIP-seq methodology for low-input applications.

Mitigating effects of ex situ application of rice straw on CH4 and N2O emissions from paddy-upland coexisting system

PubMed Central

Wang, Wei; Wu, Xiaohong; Chen, Anlei; Xie, Xiaoli; Wang, Yunqiu; Yin, Chunmei

2016-01-01

The in situ application of rice straw enhances CH4 emissions by a large margin. The ex situ application of rice straw in uplands, however, may mitigate total global warming potential (GWP) of CH4 and N2O emissions from paddy-upland coexisting systems. To evaluate the efficiency of this practice, two field trials were conducted in rice-rice-fallow and maize-rape cropping systems, respectively. Year-round measurements of CH4 and N2O emissions were conducted to evaluate the system-scaled GWP. The results showed that CH4 accounted for more than 98% of GWP in paddy. Straw removal from paddy decreased 44.7% (302.1 kg ha−1 yr−1) of CH4 emissions and 51.2% (0.31 kg ha−1 yr−1) of N2O emissions, thus decreased 44.8% (7693 kg CO2-eqv ha−1 yr−1) of annual GWP. N2O accounted for almost 100% of GWP in upland. Straw application in upland had insignificant effects on CH4 and N2O emissions, which increased GWP only by 91 kg CO2-eqv ha−1 yr−1. So, the transfer of straw from paddy to upland could decrease GWP by 7602 kg CO2-eqv ha−1 yr−1. Moreover, straw retention during late rice season contributed to 88.2% of annual GWP increment. It is recommended to transfer early rice straw to upland considering GWP mitigation, nutrient recycling and labor cost. PMID:27869209

Mitigating effects of ex situ application of rice straw on CH4 and N2O emissions from paddy-upland coexisting system

NASA Astrophysics Data System (ADS)

Wang, Wei; Wu, Xiaohong; Chen, Anlei; Xie, Xiaoli; Wang, Yunqiu; Yin, Chunmei

2016-11-01

The in situ application of rice straw enhances CH4 emissions by a large margin. The ex situ application of rice straw in uplands, however, may mitigate total global warming potential (GWP) of CH4 and N2O emissions from paddy-upland coexisting systems. To evaluate the efficiency of this practice, two field trials were conducted in rice-rice-fallow and maize-rape cropping systems, respectively. Year-round measurements of CH4 and N2O emissions were conducted to evaluate the system-scaled GWP. The results showed that CH4 accounted for more than 98% of GWP in paddy. Straw removal from paddy decreased 44.7% (302.1 kg ha-1 yr-1) of CH4 emissions and 51.2% (0.31 kg ha-1 yr-1) of N2O emissions, thus decreased 44.8% (7693 kg CO2-eqv ha-1 yr-1) of annual GWP. N2O accounted for almost 100% of GWP in upland. Straw application in upland had insignificant effects on CH4 and N2O emissions, which increased GWP only by 91 kg CO2-eqv ha-1 yr-1. So, the transfer of straw from paddy to upland could decrease GWP by 7602 kg CO2-eqv ha-1 yr-1. Moreover, straw retention during late rice season contributed to 88.2% of annual GWP increment. It is recommended to transfer early rice straw to upland considering GWP mitigation, nutrient recycling and labor cost.

Life prediction and constitutive models for engine hot section anisotropic materials

NASA Technical Reports Server (NTRS)

Swanson, G. A.; Linask, I.; Nissley, D. M.; Norris, P. P.; Meyer, T. G.; Walker, K. P.

1987-01-01

The results are presented of a program designed to develop life prediction and constitutive models for two coated single crystal alloys used in gas turbine airfoils. The two alloys are PWA 1480 and Alloy 185. The two oxidation resistant coatings are PWA 273, an aluminide coating, and PWA 286, an overlay NiCoCrAlY coating. To obtain constitutive and fatigue data, tests were conducted on uncoated and coated specimens loaded in the CH76 100 CH110 , CH76 110 CH110 , CH76 111 CH110 and CH76 123 CH110 crystallographic directions. Two constitutive models are being developed and evaluated for the single crystal materials: a micromechanic model based on crystallographic slip systems, and a macroscopic model which employs anisotropic tensors to model inelastic deformation anisotropy. Based on tests conducted on the overlay coating material, constitutive models for coatings also appear feasible and two initial models were selected. A life prediction approach was proposed for coated single crystal materials, including crack initiation either in the coating or in the substrate. The coating initiated failures dominated in the tests at load levels typical of gas turbine operation. Coating life was related to coating stress/strain history which was determined from specimen data using the constitutive models.

Mandibular Denture Base Deformation with Locator and Ball Attachments of Implant-Retained Overdentures.

PubMed

ELsyad, Moustafa Abdou; Errabti, Hatem Mokhtar; Mustafa, Aisha Zakaria

2016-12-01

The aim of this in vitro study was to evaluate and compare mandibular denture base deformation between ball and Locator attachments of implant-retained overdentures. An experimental acrylic model covered with resilient silicone mucosal simulation was constructed. Two laboratory implants were placed in the canine areas of the model. Two duplicate experimental overdentures were constructed and connected to the implants with either ball (GI) or Locator (GII) attachments. To measure overdenture strain around the attachments, 3 strain gauges were attached to the lingual polished surface of the overdentures opposite to the right implant (loading side) 2 mm above the attachment level (Ch1), at the attachment level (Ch2), and 2 mm below the attachment level (Ch3). Another 3 gauges were bonded opposite to the left implant (non-loading side) in the same manner (Ch6, Ch7, and Ch8). To measure strain at the midline of the overdentures, two strain gauges were attached in the midline at 5 mm intervals (Ch4 and Ch5). A universal testing device was used to deliver vertical static load of 50 N unilaterally and bilaterally to the first molar area to measure strain using a multi-channel digital strain meter. During bilateral load application, GII recorded higher compressive strains than GI at the majority of channels. During unilateral load application, GI recorded higher tensile strains at Ch1, Ch2, and Ch3, and GII recorded higher strains than GI at Ch6, Ch7, and Ch8. During bilateral loading the highest strain was concentrated at Ch5 for both groups. During unilateral loading, the highest strain was concentrated at Ch2 for GI, and at Ch5 for GII. Ball attachments for implant-retained overdentures were associated with significant mandibular denture base deformation over the implants compared to Locator attachments. Therefore, denture base reinforcement may be recommended with ball attachmentz to increase fracture resistance of the base. © 2015 by the American College of Prosthodontists.

Data Integration Framework Data Management Plan Remote Sensing Dataset

DTIC Science & Technology

2016-07-01

performed by the Coastal Observations and Analysis Branch (CEERD-HFA) of the Flood and Storm Protection Division (CEERD-HF), U.S. Army Engineer Research... Protection Division, Coastal Observations and Analysis Branch CESAM U.S. Army Corps of Engineers, Mobile District CESAM-OP-J U.S. Army Corps of Engineers...ER D C/ CH L SR -1 6- 2 Coastal Ocean Data Systems Program Data Integration Framework Data Management Plan Remote Sensing Dataset Co

Modelling methane emissions from natural wetlands by development and application of the TRIPLEX-GHG model

USGS Publications Warehouse

Zhu, Qing; Liu, Jinxun; Peng, C.; Chen, H.; Fang, X.; Jiang, H.; Yang, G.; Zhu, D.; Wang, W.; Zhou, X.

2014-01-01

A new process-based model TRIPLEX-GHG was developed based on the Integrated Biosphere Simulator (IBIS), coupled with a new methane (CH4) biogeochemistry module (incorporating CH4 production, oxidation, and transportation processes) and a water table module to investigate CH4 emission processes and dynamics that occur in natural wetlands. Sensitivity analysis indicates that the most sensitive parameters to evaluate CH4 emission processes from wetlands are r (defined as the CH4 to CO2 release ratio) and Q10 in the CH4 production process. These two parameters were subsequently calibrated to data obtained from 19 sites collected from approximately 35 studies across different wetlands globally. Being heterogeneously spatially distributed, r ranged from 0.1 to 0.7 with a mean value of 0.23, and the Q10 for CH4 production ranged from 1.6 to 4.5 with a mean value of 2.48. The model performed well when simulating magnitude and capturing temporal patterns in CH4 emissions from natural wetlands. Results suggest that the model is able to be applied to different wetlands under varying conditions and is also applicable for global-scale simulations.

Test Plan: WIPP bin-scale CH TRU waste tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molecke, M.A.

1990-08-01

This WIPP Bin-Scale CH TRU Waste Test program described herein will provide relevant composition and kinetic rate data on gas generation and consumption resulting from TRU waste degradation, as impacted by synergistic interactions due to multiple degradation modes, waste form preparation, long-term repository environmental effects, engineered barrier materials, and, possibly, engineered modifications to be developed. Similar data on waste-brine leachate compositions and potentially hazardous volatile organic compounds released by the wastes will also be provided. The quantitative data output from these tests and associated technical expertise are required by the WIPP Performance Assessment (PA) program studies, and for the scientificmore » benefit of the overall WIPP project. This Test Plan describes the necessary scientific and technical aspects, justifications, and rational for successfully initiating and conducting the WIPP Bin-Scale CH TRU Waste Test program. This Test Plan is the controlling scientific design definition and overall requirements document for this WIPP in situ test, as defined by Sandia National Laboratories (SNL), scientific advisor to the US Department of Energy, WIPP Project Office (DOE/WPO). 55 refs., 16 figs., 19 tabs.« less

An integrated 3-Dimensional Genome Modeling Engine for data-driven simulation of spatial genome organization.

PubMed

Szałaj, Przemysław; Tang, Zhonghui; Michalski, Paul; Pietal, Michal J; Luo, Oscar J; Sadowski, Michał; Li, Xingwang; Radew, Kamen; Ruan, Yijun; Plewczynski, Dariusz

2016-12-01

ChIA-PET is a high-throughput mapping technology that reveals long-range chromatin interactions and provides insights into the basic principles of spatial genome organization and gene regulation mediated by specific protein factors. Recently, we showed that a single ChIA-PET experiment provides information at all genomic scales of interest, from the high-resolution locations of binding sites and enriched chromatin interactions mediated by specific protein factors, to the low resolution of nonenriched interactions that reflect topological neighborhoods of higher-order chromosome folding. This multilevel nature of ChIA-PET data offers an opportunity to use multiscale 3D models to study structural-functional relationships at multiple length scales, but doing so requires a structural modeling platform. Here, we report the development of 3D-GNOME (3-Dimensional Genome Modeling Engine), a complete computational pipeline for 3D simulation using ChIA-PET data. 3D-GNOME consists of three integrated components: a graph-distance-based heat map normalization tool, a 3D modeling platform, and an interactive 3D visualization tool. Using ChIA-PET and Hi-C data derived from human B-lymphocytes, we demonstrate the effectiveness of 3D-GNOME in building 3D genome models at multiple levels, including the entire genome, individual chromosomes, and specific segments at megabase (Mb) and kilobase (kb) resolutions of single average and ensemble structures. Further incorporation of CTCF-motif orientation and high-resolution looping patterns in 3D simulation provided additional reliability of potential biologically plausible topological structures. © 2016 Szałaj et al.; Published by Cold Spring Harbor Laboratory Press.

Catalytic and electrochemical behaviour of solid oxide fuel cell operated with simulated-biogas mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dang-Long, T., E-mail: 3TE14098G@kyushu-u.ac.jp; Quang-Tuyen, T., E-mail: tran.tuyen.quang.314@m.kyushu-u.ac.jp; Shiratori, Y., E-mail: shiratori.yusuke.500@m.kyushu-u.ac.jp

2016-06-03

Being produced from organic matters of wastes (bio-wastes) through a fermentation process, biogas mainly composed of CH{sub 4} and CO{sub 2} and can be considered as a secondary energy carrier derived from solar energy. To generate electricity from biogas through the electrochemical process in fuel cells is a state-of-the-art technology possessing higher energy conversion efficiency without harmful emissions compared to combustion process in heat engines. Getting benefits from high operating temperature such as direct internal reforming ability and activation of electrochemical reactions to increase overall system efficiency, solid oxide fuel cell (SOFC) system operated with biogas becomes a promising candidatemore » for distributed power generator for rural applications leading to reductions of environmental issues caused by greenhouse effects and bio-wastes. CO{sub 2} reforming of CH{sub 4} and electrochemical oxidation of the produced syngas (H{sub 2}–CO mixture) are two main reaction processes within porous anode material of SOFC. Here catalytic and electrochemical behavior of Ni-ScSZ (scandia stabilized-zirconia) anode in the feed of CH{sub 4}–CO{sub 2} mixtures as simulated-biogas at 800 °C were evaluated. The results showed that CO{sub 2} had strong influences on both reaction processes. The increase in CO{sub 2} partial pressure resulted in the decrease in anode overvoltage, although open-circuit voltage was dropped. Besides that, the simulation result based on a power-law model for equimolar CH{sub 4}−CO{sub 2} mixture revealed that coking hazard could be suppressed along the fuel flow channel in both open-circuit and closed-circuit conditions.« less

An anaerobic-aerobic sequential batch process with simultaneous methanogenesis and short-cut denitrification for the treatment of marine biofoulings.

PubMed

Akizuki, S; Toda, T

2018-04-01

Although combination of denitritation and methanogenesis for wastewater treatment has been widely investigated, an application of this technology to solid waste treatment has been rarely studied. This study investigated an anaerobic-aerobic batch system with simultaneous denitritation-methanogenesis as an effective treatment for marine biofoulings, which is a major source of intermittently discharged organic solid wastes. Preliminary NO 2 - -exposed sludge was inoculated to achieve stable methanogenesis process without NO 2 - inhibition. Both high NH 4 + -N removal of 99.5% and high NO 2 - -N accumulation of 96.4% were achieved on average during the nitritation step. Sufficient CH 4 recovery of 101 L-CH 4 kg-COD -1 was achieved, indicating that the use of NO 2 - -exposed sludge is effective to avoid NO 2 - inhibition on methanogenesis. Methanogenesis was the main COD utilization pathway when the substrate solubilization occurred actively, while denitritation was the main when solubilization was limited because of substrate shortage. The results showed a high COD removal efficiency of 96.0% and a relatively low nitrogen removal efficiency of 64.4%. Fitting equations were developed to optimize the effluent exchange ratio. The estimated results showed that the increase of effluent exchange ratio during the active solubilization period increased the nitrogen removal efficiency but decreased CH 4 content in biogas. An appropriate effluent exchange ratio with high anaerobic effluent quality below approximately 120 mg-N L -1 as well as sufficient CH 4 gas quality which can be used as fuel for gas engine generator was achieved by daily effluent exchange of 80% during the first week and 5% during the subsequent 8 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

Section Editors

NASA Astrophysics Data System (ADS)

Groep, D. L.; Bonacorsi, D.

2014-06-01

1. Data Acquisition, Trigger and Controls Niko NeufeldCERNniko.neufeld@cern.ch Tassos BeliasDemokritosbelias@inp.demokritos.gr Andrew NormanFNALanorman@fnal.gov Vivian O'DellFNALodell@fnal.gov 2. Event Processing, Simulation and Analysis Rolf SeusterTRIUMFseuster@cern.ch Florian UhligGSIf.uhlig@gsi.de Lorenzo MonetaCERNLorenzo.Moneta@cern.ch Pete ElmerPrincetonpeter.elmer@cern.ch 3. Distributed Processing and Data Handling Nurcan OzturkU Texas Arlingtonnurcan@uta.edu Stefan RoiserCERNstefan.roiser@cern.ch Robert IllingworthFNAL Davide SalomoniINFN CNAFDavide.Salomoni@cnaf.infn.it Jeff TemplonNikheftemplon@nikhef.nl 4. Data Stores, Data Bases, and Storage Systems David LangeLLNLlange6@llnl.gov Wahid BhimjiU Edinburghwbhimji@staffmail.ed.ac.uk Dario BarberisGenovaDario.Barberis@cern.ch Patrick FuhrmannDESYpatrick.fuhrmann@desy.de Igor MandrichenkoFNALivm@fnal.gov Mark van de SandenSURF SARA sanden@sara.nl 5. Software Engineering, Parallelism & Multi-Core Solveig AlbrandLPSC/IN2P3solveig.albrand@lpsc.in2p3.fr Francesco GiacominiINFN CNAFfrancesco.giacomini@cnaf.infn.it Liz SextonFNALsexton@fnal.gov Benedikt HegnerCERNbenedikt.hegner@cern.ch Simon PattonLBNLSJPatton@lbl.gov Jim KowalkowskiFNAL jbk@fnal.gov 6. Facilities, Infrastructures, Networking and Collaborative Tools Maria GironeCERNMaria.Girone@cern.ch Ian CollierSTFC RALian.collier@stfc.ac.uk Burt HolzmanFNALburt@fnal.gov Brian Bockelman U Nebraskabbockelm@cse.unl.edu Alessandro de SalvoRoma 1Alessandro.DeSalvo@ROMA1.INFN.IT Helge MeinhardCERN Helge.Meinhard@cern.ch Ray PasetesFNAL rayp@fnal.gov Steven GoldfarbU Michigan Steven.Goldfarb@cern.ch

An Introduction to the Fundamentals of Chemistry for the Marine Engineer - An Audio-Tutorial Correspondence Course (CH-1C).

ERIC Educational Resources Information Center

Schlenker, Richard M.

This document provides a study guide for a three-credit-hour fundamentals of chemistry course for marine engineer majors. The course is composed of 17 minicourses including: chemical reactions, atomic theory, solutions, corrosion, organic chemistry, water pollution, metric system, and remedial mathematics skills. Course grading, objectives,…

Two-Photon Holographic Stimulation of ReaChR

PubMed Central

Chaigneau, Emmanuelle; Ronzitti, Emiliano; Gajowa, Marta A.; Soler-Llavina, Gilberto J.; Tanese, Dimitrii; Brureau, Anthony Y. B.; Papagiakoumou, Eirini; Zeng, Hongkui; Emiliani, Valentina

2016-01-01

Optogenetics provides a unique approach to remotely manipulate brain activity with light. Reaching the degree of spatiotemporal control necessary to dissect the role of individual cells in neuronal networks, some of which reside deep in the brain, requires joint progress in opsin engineering and light sculpting methods. Here we investigate for the first time two-photon stimulation of the red-shifted opsin ReaChR. We use two-photon (2P) holographic illumination to control the activation of individually chosen neurons expressing ReaChR in acute brain slices. We demonstrated reliable action potential generation in ReaChR-expressing neurons and studied holographic 2P-evoked spiking performances depending on illumination power and pulse width using an amplified laser and a standard femtosecond Ti:Sapphire oscillator laser. These findings provide detailed knowledge of ReaChR's behavior under 2P illumination paving the way for achieving in depth remote control of multiple cells with high spatiotemporal resolution deep within scattering tissue. PMID:27803649

Function and limits of biofilters for the removal of methane in exhaust gases from the pig industry.

PubMed

Veillette, Marc; Girard, Matthieu; Viens, Pascal; Brzezinski, Ryszard; Heitz, Michèle

2012-05-01

The agricultural sector is responsible for an important part of Canadian greenhouse gas (GHG) emissions, 8 % of the 747 Mt eq. CO(2) emitted each year. The pork industry, a key sector of the agrifood industry, has had a rapid growth in Canada since the middle 1980s. For this industry, slurry storage accounts for the major part of methane (CH(4)) emissions, a GHG 25 times higher than carbon dioxide (CO(2)) on a 100-year time horizon. Intending to reduce these emissions, biofiltration, a process effective to treat CH(4) from landfills and coal mines, could be effective to treat CH(4) from the pig industry. Biofiltration is a complex process that requires the understanding of the biological process of CH(4) oxidation and a control of the engineering parameters (filter bed, temperature, etc.). Some biofiltration studies show that this technology could be used to treat CH(4) at a relatively low cost and with a relatively high purification performance.

Engineered Human Antibody Constant Domains with Increased Stability*S⃞

PubMed Central

Gong, Rui; Vu, Bang K.; Feng, Yang; Prieto, DaRue A.; Dyba, Marzena A.; Walsh, Joseph D.; Prabakaran, Ponraj; Veenstra, Timothy D.; Tarasov, Sergey G.; Ishima, Rieko; Dimitrov, Dimiter S.

2009-01-01

The immunoglobulin (Ig) constant CH2 domain is critical for antibody effector functions. Isolated CH2 domains are promising as scaffolds for construction of libraries containing diverse binders that could also confer some effector functions. However, previous work has shown that an isolated murine CH2 domain is relatively unstable to thermally induced unfolding. To explore unfolding mechanisms of isolated human CH2 and increase its stability γ1 CH2 was cloned and a panel of cysteine mutants was constructed. Human γ1 CH2 unfolded at a higher temperature (Tm = 54.1 °C, as measured by circular dichroism) than that previously reported for a mouse CH2 (41 °C). One mutant (m01) was remarkably stable (Tm = 73.8 °C). Similar results were obtained by differential scanning calorimetry. This mutant was also significantly more stable than the wild-type CH2 against urea induced unfolding (50% unfolding at urea concentration of 6.8 m versus 4.2 m). The m01 was highly soluble and monomeric. The existence of the second disulfide bond in m01 and its correct position were demonstrated by mass spectrometry and nuclear magnetic resonance spectroscopy, respectively. The loops were on average more flexible than the framework in both CH2 and m01, and the overall secondary structure was not affected by the additional disulfide bond. These data suggest that a human CH2 domain is relatively stable to unfolding at physiological temperature, and that both CH2 and the highly stable mutant m01 are promising new scaffolds for the development of therapeutics against human diseases. PMID:19307178

Macro- and micro-designed chitosan-alginate scaffold architecture by three-dimensional printing and directional freezing.

PubMed

Reed, Stephanie; Lau, Grace; Delattre, Benjamin; Lopez, David Don; Tomsia, Antoni P; Wu, Benjamin M

2016-01-07

While many tissue-engineered constructs aim to treat cartilage defects, most involve chondrocyte or stem cell seeding on scaffolds. The clinical application of cell-based techniques is limited due to the cost of maintaining cellular constructs on the shelf, potential immune response to allogeneic cell lines, and autologous chondrocyte sources requiring biopsy from already diseased or injured, scarce tissue. An acellular scaffold that can induce endogenous influx and homogeneous distribution of native stem cells from bone marrow holds great promise for cartilage regeneration. This study aims to develop such an acellular scaffold using designed, channeled architecture that simultaneously models the native zones of articular cartilage and subchondral bone. Highly porous, hydrophilic chitosan-alginate (Ch-Al) scaffolds were fabricated in three-dimensionally printed (3DP) molds designed to create millimeter scale macro-channels. Different polymer preform casting techniques were employed to produce scaffolds from both negative and positive 3DP molds. Macro-channeled scaffolds improved cell suspension distribution and uptake overly randomly porous scaffolds, with a wicking volumetric flow rate of 445.6 ± 30.3 mm(3) s(-1) for aqueous solutions and 177 ± 16 mm(3) s(-1) for blood. Additionally, directional freezing was applied to Ch-Al scaffolds, resulting in lamellar pores measuring 300 μm and 50 μm on the long and short axes, thus creating micrometer scale micro-channels. After directionally freezing Ch-Al solution cast in 3DP molds, the combined macro- and micro-channeled scaffold architecture enhanced cell suspension uptake beyond either macro- or micro-channels alone, reaching a volumetric flow rate of 1782.1 ± 48 mm(3) s(-1) for aqueous solutions and 440.9 ± 0.5 mm(3) s(-1) for blood. By combining 3DP and directional freezing, we can control the micro- and macro-architecture of Ch-Al to drastically improve cell influx into and distribution within the scaffold, while achieving porous zones that mimic articular cartilage zonal architecture. In future applications, precisely controlled micro- and macro-channels have the potential to assist immediate endogenous bone marrow uptake, stimulate chondrogenesis, and encourage vascularization of bone in an osteochondral scaffold.

Low-temperature upgrading of low-calorific biogas for CO2 mitigation using DBD-catalyst hybrid reactor

NASA Astrophysics Data System (ADS)

Nozaki, Tomohiro; Tsukijihara, Hiroyuki; Fukui, Wataru; Okazaki, Ken

2006-10-01

Although huge amounts of biogas, which consists of 20-60% of CH4 in CO2/N2, can be obtained from landfills, coal mines, and agricultural residues, most of them are simply flared and wasted: because global warming potential of biogas is 5-15 times as potent as CO2. Poor combustibility of such biogas makes it difficult to utilize in conventional energy system. The purpose of this project is to promote the profitable recovery of methane from poor biogas via non-thermal plasma technology. We propose low-temperature steam reforming of biogas using DBD generated in catalyst beds. Methane is partially converted into hydrogen, and then fed into internal combustion engines for improved ignition stability as well as efficient operation. Low-temperature steam reforming is beneficial because exhaust gas from an engine can be used to activate catalyst beds. Space velocity (3600-15000 hr-1), reaction temperature (300-650^oC), and energy cost (30-150 kJ per mol CH4) have been investigated with simulated biogas (20-60% CH4 in mixtures of CO2/N2). The DBD enhances reaction rate of CH4 by a factor of ten at given catalyst temperatures, which is a rate-determining step of methane steam reforming, while species concentration of upgraded biogas was governed by thermodynamic equilibrium in the presence of catalyst.

The Effect of Tungsten and Niobium on the Stress Relaxation Rates of Disk Alloy CH98

NASA Technical Reports Server (NTRS)

Gayda, John

2003-01-01

Gas turbine engines for future subsonic transports will probably have higher pressure ratios which will require nickel-base superalloy disks with 1300 to 1400 F temperature capability. Several advanced disk alloys are being developed to fill this need. One of these, CH98, is a promising candidate for gas turbine engines and is being studied in NASA s Advanced Subsonic Technology (AST) program. For large disks, residual stresses generated during quenching from solution heat treatment are often reduced by a stabilization heat treatment, in which the disk is heated to 1500 to 1600 F for several hours followed by a static air cool. The reduction in residual stress levels lessens distortion during machining of disks. However, previous work on CH98 has indicated that stabilization treatments decrease creep capability. Additions of the refractory elements tungsten and niobium improve tensile and creep properties after stabilization, while maintaining good crack growth resistance at elevated temperatures. As the additions of refractory elements increase creep capability, they might also effect stress relaxation rates and therefore the reduction in residual stress levels obtained for a given stabilization treatment. To answer this question, the stress relaxation rates of CH98 with and without tungsten and niobium additions are compared in this paper for temperatures and times generally employed in stabilization treatments on modern disk alloys.

40 CFR 1065.695 - Data requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... restriction. (v) Charge air cooler volume. (vi) Charge air cooler outlet temperature, specified engine.... (iii) “Dry-to-wet” correction. (iv) NMHC, CH4, and contamination correction. (v) NOX humidity...

Biotinylated Rh(III) complexes in engineered streptavidin for accelerated asymmetric C-H activation.

PubMed

Hyster, Todd K; Knörr, Livia; Ward, Thomas R; Rovis, Tomislav

2012-10-26

Enzymes provide an exquisitely tailored chiral environment to foster high catalytic activities and selectivities, but their native structures are optimized for very specific biochemical transformations. Designing a protein to accommodate a non-native transition metal complex can broaden the scope of enzymatic transformations while raising the activity and selectivity of small-molecule catalysis. Here, we report the creation of a bifunctional artificial metalloenzyme in which a glutamic acid or aspartic acid residue engineered into streptavidin acts in concert with a docked biotinylated rhodium(III) complex to enable catalytic asymmetric carbon-hydrogen (C-H) activation. The coupling of benzamides and alkenes to access dihydroisoquinolones proceeds with up to nearly a 100-fold rate acceleration compared with the activity of the isolated rhodium complex and enantiomeric ratios as high as 93:7.

Enhanced Photovoltaic Performance of Perovskite Solar Cells by Copper Chloride (CuCl2) as an Additive in Single Solvent Perovskite Precursor

NASA Astrophysics Data System (ADS)

Emrul Kayesh, Md.; Matsuishi, Kiyoto; Chowdhury, Towhid H.; Kaneko, Ryuji; Noda, Takeshi; Islam, Ashraful

2018-05-01

In this letter, we have introduced copper chloride (CuCl2) as an additive in the CH3NH3PbI3 precursor solution to improve the surface morphology and crystallinity of CH3NH3PbI3 films in a single solvent system. Our optimized perovskite solar cells (PSCs) with 2.5 mol% CuCl2 additive showed best power conversion efficiency (PCE) of 15.22%. The PCE of the PSCs fabricated by CuCl2 (2.5 mol%) additive engineering was 56% higher than the PSC fabricated with pristine CH3NH3PbI3.

Simulating the impact of cholinesterase-inhibiting pesticides on non-target wildlife in irrigated crops

USGS Publications Warehouse

Pisani, J.M.; Grant, W.E.; Mora, M.A.

2008-01-01

We present a simulation model for risk assessment of the impact of insecticide inhibitors of cholinesterase (ChE) applied in irrigated agricultural fields on non-target wildlife. The model, which we developed as a compartment model based on difference equations (??t = 1 h), consists of six submodels describing the dynamics of (1) insecticide application, (2) insecticide movement into floodable soil, (3) irrigation and rain, (4) insecticide dissolution in water, (5) foraging and insecticide intake from water, and (6) ChE inhibition and recovery. To demonstrate application of the model, we simulated historical and "worst-case" scenarios of the impact of ChE-inhibiting insecticides on white-winged doves (Zenaida asiatica) inhabiting natural brushland adjacent to cotton and sugarcane fields in the Lower Rio Grande Valley of Texas, USA. Only when a rain event occurred just after insecticide application did predicted levels of ChE inhibition surpass the diagnostic level of 20% exposure. The present model should aid in assessing the effect of ChE-inhibiting insecticides on ChE activity of different species that drink contaminated water from irrigated agricultural fields, and in identifying specific situations in which the juxtaposition of environmental conditions and management schemes could result in a high risk to non-target wildlife. ?? 2007 Elsevier B.V. All rights reserved.

Warmer and drier conditions and nitrogen fertilizer application altered methanotroph abundance and methane emissions in a vegetable soil.

PubMed

Ran, Yu; Xie, Jianli; Xu, Xiaoya; Li, Yong; Liu, Yapeng; Zhang, Qichun; Li, Zheng; Xu, Jianming; Di, Hongjie

2017-01-01

Methane (CH 4 ) is a potent greenhouse gas, and soil can both be a source and sink for atmospheric CH 4 . It is not clear how future climate change may affect soil CH 4 emissions and related microbial communities. The aim of this study was to determine the interactive effects of a simulated warmer and drier climate scenarios and the application of different nitrogen (N) sources (urea and manure) on CH 4 emissions and related microbial community abundance in a vegetable soil. Greenhouses were used to control simulated climate conditions which gave 2.99 °C warmer and 6.2% lower water content conditions. The field experiment was divided into two phases. At the beginning of phase II, half of the greenhouses were removed to study possible legacy effects of the simulated warmer and drier conditions. The responses in methanogen and methanotroph abundance to a simulated climate change scenario were determined using real-time PCR. The results showed that the simulated warmer and drier conditions in the greenhouses significantly decreased CH 4 emissions largely due to the lower soil moisture content. For the same reason, CH 4 emissions of treatments in phase I were much lower than the same treatments in phase II. The abundance of methanotrophs showed a more significant response than methanogens to the simulated climate change scenario, increasing under simulated drier conditions. Methanogenic community abundance remained low, except where manure was applied which provided a source of organic C that stimulated methanogen growth. Soil moisture content was a major driver for methanotroph abundance and strongly affected CH 4 emissions. The application of N source decreased CH 4 emissions probably because of increased methanotrophic activity. CH 4 emissions were positively correlated to methanogenic abundance and negatively correlated to methanotrophic abundance. These results demonstrate that projected future climate change conditions can have a feedback impact on CH 4 emissions from the soil by altering soil conditions (particularly soil moisture) and related microbial communities.

Enhanced cytocompatibility and reduced genotoxicity of polydimethylsiloxane modified by plasma immersion ion implantation.

PubMed

Tong, Liping; Zhou, Wenhua; Zhao, Yuetao; Yu, Xuefeng; Wang, Huaiyu; Chu, Paul K

2016-12-01

Polydimethylsiloxane(PDMS) is a common industrial polymer with advantages such as ease of fabrication, tunable hardness, and other desirable properties, but the basic (-OSi(CH 3 ) 2 -) n structure in PDMS is inherently hydrophobic thereby hampering application to biomedical engineering. In this study, plasma immersion ion implantation (PIII) is conducted on PDMS to improve the biological properties. PIII forms wrinkled "herringbone" patterns and abundant O-containing functional groups on PDMS to alter the surface hydrophilicity. The biocompatibility of the modified PDMS is assessed with Chinese hamster ovarian cells and compared to that of the untreated PDMS. Our results reveal that the PDMS samples after undergoing PIII have better cytocompatibility and lower genotoxicity. PIII which is a non-line-of-sight technique extends the application of PDMS to the biomedical field. Copyright © 2016 Elsevier B.V. All rights reserved.

High Efficiency push-pull class E amplifiers for fusion rocket engines

NASA Astrophysics Data System (ADS)

Gaitan, Gabriel; Ham, Eric; Cohen, S. A.; Swanson, Charles; Chen, Minjie; Brunkhorst, Christopher

2017-10-01

In a Field Reversed Configuration fusion reactor, ions in the plasma are heated by an antenna operating at RF frequencies. This paper presents how push-pull class E amplifiers can be used to efficiently drive this antenna in the MHz range, from 0.5MHz to 4 MHz, while maintaining low harmonic content in the output signal. We offer four different configurations that present a trade-off between efficiency and low harmonic content. The paper presents theoretical values and breadboard results from these configurations, which operate at a power of around 100W. For a practical design, multiple amplifiers would be linked in parallel and would power the RF antenna at around 1MW. These designs provide multiple different options for reactor systems that could be used in a variety of applications, from power plants on the ground to rocket engines in space. This work was supported, in part, by DOE Contract Number DE-AC02-09CH11466 and Princeton Environmental Institute.

Encapsulation of CH3NH3PbBr3 Perovskite Quantum Dots in MOF-5 Microcrystals as a Stable Platform for Temperature and Aqueous Heavy Metal Ion Detection.

PubMed

Zhang, Diwei; Xu, Yan; Liu, Quanlin; Xia, Zhiguo

2018-04-16

The stability issue of organometallic halide perovskites remains a great challenge for future research as to their applicability in different functional material fields. Herein, a novel and facile two-step synthesis procedure is reported for encapsulation of CH 3 NH 3 PbBr 3 perovskite quantum dots (QDs) in MOF-5 microcrystals, where PbBr 2 and CH 3 NH 3 Br precursors are added stepwise to fabricate stable CH 3 NH 3 PbBr 3 @MOF-5 composites. In comparison to CH 3 NH 3 PbBr 3 QDs, CH 3 NH 3 PbBr 3 @MOF-5 composites exhibited highly improved water resistance and thermal stability, as well as better pH adaptability over a wide range. Luminescent investigations demonstrate that CH 3 NH 3 PbBr 3 @MOF-5 composites not only featured excellent sensing properties with respect to temperature changes from 30 to 230 °C but also exhibited significant selective luminescent response to several different metal ions in aqueous solution. These outstanding characteristics indicate that the stable CH 3 NH 3 PbBr 3 @MOF-5 composites are potentially interesting for application in fluorescence sensors or detectors.

Immunoglobulin Fc Heterodimer Platform Technology: From Design to Applications in Therapeutic Antibodies and Proteins.

PubMed

Ha, Ji-Hee; Kim, Jung-Eun; Kim, Yong-Sung

2016-01-01

The monospecific and bivalent characteristics of naturally occurring immunoglobulin G (IgG) antibodies depend on homodimerization of the fragment crystallizable (Fc) regions of two identical heavy chains (HCs) and the subsequent assembly of two identical light chains (LCs) via disulfide linkages between each HC and LC. Immunoglobulin Fc heterodimers have been engineered through modifications to the CH3 domain interface, with different mutations on each domain such that the engineered Fc fragments, carrying the CH3 variant pair, preferentially form heterodimers rather than homodimers. Many research groups have adopted different strategies to generate Fc heterodimers, with the goal of high heterodimerization yield, while retaining biophysical and biological properties of the wild-type Fc. Based on their ability to enforce heterodimerization between the two different HCs, the established Fc heterodimers have been extensively exploited as a scaffold to generate bispecific antibodies (bsAbs) in full-length IgG and IgG-like formats. These have many of the favorable properties of natural IgG antibodies, such as high stability, long serum half-life, low immunogenicity, and immune effector functions. As of July 2016, more than seven heterodimeric Fc-based IgG-format bsAbs are being evaluated in clinical trials. In addition to bsAbs, heterodimeric Fc technology is very promising for the generation of Fc-fused proteins and peptides, as well as cytokines (immunocytokines), which can present the fusion partners in the natural monomeric or heterodimeric form rather than the artificial homodimeric form with wild-type Fc. Here, we present relevant concepts and strategies for the generation of heterodimeric Fc proteins, and their application in the development of bsAbs in diverse formats for optimal biological activity. In addition, we describe wild-type Fc-fused monomeric and heterodimeric proteins, along with the difficulties associated with their preparations, and discuss the use of heterodimeric Fc as an alternative scaffold of wild-type Fc for naturally monomeric or heterodimeric proteins, to create Fc-fusion proteins with novel therapeutic modality.

10 CFR 430.4 - Sources for information and guidance.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., 1993. (2) [Reserved] (c) IEEE. Institute of Electrical and Electronics Engineers, Inc., 3 Park Avenue....ch. (1) IEC 62301, Household electrical appliances—Measurement of standby power, First Edition, June...

10 CFR 430.4 - Sources for information and guidance.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., 1993. (2) [Reserved] (c) IEEE. Institute of Electrical and Electronics Engineers, Inc., 3 Park Avenue....ch. (1) IEC 62301, Household electrical appliances—Measurement of standby power, First Edition, June...

10 CFR 430.4 - Sources for information and guidance.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., 1993. (2) [Reserved] (c) IEEE. Institute of Electrical and Electronics Engineers, Inc., 3 Park Avenue....ch. (1) IEC 62301, Household electrical appliances—Measurement of standby power, First Edition, June...

10 CFR 430.4 - Sources for information and guidance.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., 1993. (2) [Reserved] (c) IEEE. Institute of Electrical and Electronics Engineers, Inc., 3 Park Avenue....ch. (1) IEC 62301, Household electrical appliances—Measurement of standby power, First Edition, June...

40 CFR 1065.695 - Data requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... restriction. (v) Charge air cooler volume. (vi) Charge air cooler outlet temperature, specified engine... following: (i) Drift correction. (ii) Noise correction. (iii) “Dry-to-wet” correction. (iv) NMHC, CH4, and...

40 CFR 1065.695 - Data requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... restriction. (v) Charge air cooler volume. (vi) Charge air cooler outlet temperature, specified engine... following: (i) Drift correction. (ii) Noise correction. (iii) “Dry-to-wet” correction. (iv) NMHC, CH4, and...

40 CFR 1065.695 - Data requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... restriction. (v) Charge air cooler volume. (vi) Charge air cooler outlet temperature, specified engine... following: (i) Drift correction. (ii) Noise correction. (iii) “Dry-to-wet” correction. (iv) NMHC, CH4, and...

Air emissions of ammonia and methane from livestock operations: valuation and policy options.

PubMed

Shih, Jhih-Shyang; Burtraw, Dallas; Palmer, Karen; Siikamäki, Juha

2008-09-01

The animal husbandry industry is a major emitter of ammonia (NH3), which is a precursor of fine particulate matter (PM2.5)--arguably, the number-one environment-related public health threat facing the nation. The industry is also a major emitter of methane (CH4), which is an important greenhouse gas (GHG). We present an integrated process model of the engineering economics of technologies to reduce NH3 and CH4 emissions at dairy operations in California. Three policy options are explored: PM offset credits for NH3 control, GHG offset credits for CH4 control, and expanded net metering policies to provide revenue for the sale of electricity generated from captured methane (CH4) gas. Individually these policies vary substantially in the economic incentives they provide for farm operators to reduce emissions. We report on initial steps to fully develop the integrated process model that will provide guidance for policy-makers.

New semiconductor laser technology for gas sensing applications in the 1650nm range

NASA Astrophysics Data System (ADS)

Morrison, Gordon B.; Sherman, Jes; Estrella, Steven; Moreira, Renan L.; Leisher, Paul O.; Mashanovitch, Milan L.; Stephen, Mark; Numata, Kenji; Wu, Stewart; Riris, Haris

2017-08-01

Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. CH4 also contributes to pollution in the lower atmosphere through chemical reactions leading to ozone production. Recent developments of LIDAR measurement technology for CH4 have been previously reported by Goddard Space Flight Center (GSFC). In this paper, we report on a novel, high-performance tunable semiconductor laser technology developed by Freedom Photonics for the 1650nm wavelength range operation, and for LIDAR detection of CH4. Devices described are monolithic, with simple control, and compatible with low-cost fabrication techniques. We present 3 different types of tunable lasers implemented for this application.

Genetically encoded calcium indicators for multi-color neural activity imaging and combination with optogenetics

PubMed Central

Akerboom, Jasper; Carreras Calderón, Nicole; Tian, Lin; Wabnig, Sebastian; Prigge, Matthias; Tolö, Johan; Gordus, Andrew; Orger, Michael B.; Severi, Kristen E.; Macklin, John J.; Patel, Ronak; Pulver, Stefan R.; Wardill, Trevor J.; Fischer, Elisabeth; Schüler, Christina; Chen, Tsai-Wen; Sarkisyan, Karen S.; Marvin, Jonathan S.; Bargmann, Cornelia I.; Kim, Douglas S.; Kügler, Sebastian; Lagnado, Leon; Hegemann, Peter; Gottschalk, Alexander; Schreiter, Eric R.; Looger, Loren L.

2013-01-01

Genetically encoded calcium indicators (GECIs) are powerful tools for systems neuroscience. Here we describe red, single-wavelength GECIs, “RCaMPs,” engineered from circular permutation of the thermostable red fluorescent protein mRuby. High-resolution crystal structures of mRuby, the red sensor RCaMP, and the recently published red GECI R-GECO1 give insight into the chromophore environments of the Ca2+-bound state of the sensors and the engineered protein domain interfaces of the different indicators. We characterized the biophysical properties and performance of RCaMP sensors in vitro and in vivo in Caenorhabditis elegans, Drosophila larvae, and larval zebrafish. Further, we demonstrate 2-color calcium imaging both within the same cell (registering mitochondrial and somatic [Ca2+]) and between two populations of cells: neurons and astrocytes. Finally, we perform integrated optogenetics experiments, wherein neural activation via channelrhodopsin-2 (ChR2) or a red-shifted variant, and activity imaging via RCaMP or GCaMP, are conducted simultaneously, with the ChR2/RCaMP pair providing independently addressable spectral channels. Using this paradigm, we measure calcium responses of naturalistic and ChR2-evoked muscle contractions in vivo in crawling C. elegans. We systematically compare the RCaMP sensors to R-GECO1, in terms of action potential-evoked fluorescence increases in neurons, photobleaching, and photoswitching. R-GECO1 displays higher Ca2+ affinity and larger dynamic range than RCaMP, but exhibits significant photoactivation with blue and green light, suggesting that integrated channelrhodopsin-based optogenetics using R-GECO1 may be subject to artifact. Finally, we create and test blue, cyan, and yellow variants engineered from GCaMP by rational design. This engineered set of chromatic variants facilitates new experiments in functional imaging and optogenetics. PMID:23459413

Large Eddy Simulation of Flame-Turbulence Interactions in a LOX-CH4 Shear Coaxial Injector

DTIC Science & Technology

2012-01-01

heat transfer from dense to light fluids.A previous study on LOX/H2 flames39,40 have pointed the limitations of central scheme to predict such large...pp. 151–169. 39Masquelet, M., Simulations of a Sub-scale Liquid Rocket Engine: Transient Heat Transfer in a Real Gas Environment , Master’s thesis...Eddy Simulation of a cryogenic flame issued from a LOX-CH4 shear coaxial injector. The operating pressure is above the critical pressure for both

Cockpit Accommodation Assessment of the Bell 412CF Helicopter (Evaluation du Poste de Pilotage de l’Hellcoptere Bell 412CF)

DTIC Science & Technology

2009-12-01

Research, Ottawa , 1998 as issued jointly by the Canadian Institutes of Health Research, the Natural Sciences and Engineering Research Council of Canada...Flight Rules ) skills. Nine Bell 412CF helicopters were produced from existing CH-146 Griffons, which posed technical challenges. One such compromise was...IFR (Instrument Flight Rules ) skills. Nine Bell 412CF helicopters were produced from existing CH-146 Griffons, which posed technical challenges. One

Development of a Scaled Quantum Mechanical Force Field for Peptides in Aqueous Solution

DTIC Science & Technology

1996-03-01

differ. Raman and IR techniques are complimentary which helps in assignment of observed vibrational modes. As described in beginning organic ...1588 I NH, .i.sor(98) 2076 2100 24 CH3 55(95) 2125 2207 82 CH3 as’ (56), CH3 as’ (43) 2235 2253 18 CH3 as’(55), CH3 as’(41) 2888 COff .(100) 3155 NH...Application of self- consistent-field ab initio calculations to organic molecules I. Equilibrium struc- ture and force constants of hydrocarbons

Synoptic Meteorology during the SNOW-ONE-A Field Experiment.

DTIC Science & Technology

1983-05-01

AD ,34 888 SYNOPTIC METEOROLOGY DURING tHE SNOW-ONE A FIELD I EXPERIMENTIUP COLD REGIONS RESEARCH AND ENGINEERING LABHANOVER NN M A BILELLO MAY 83...PROGRAM ELEMENT. PROJECT. TASK U. S. Army Cold Regions Research and AREA & WORK UNIT NUMBERS Engineering Laboratory DA Project 4A762730AT42- Hanover, New...Hampshire 03755 B-El-5 It. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE Office of the Ch ief of Engineers May 1983 Washington, D.C. 20314 13

Effects on birds of fenthion aerial application for mosquito control

USGS Publications Warehouse

DeWeese, L.R.; McEwen, L.C.; Settimi, L.A.; Deblinger, R.D.

1983-01-01

Effects on birds of an aerial application of fenthion, a potent organophosphorus cholinesterase (ChE)-inhibiting insecticide, were assessed on four study sites 1.8 to 3.6 km2 in size. These sites were located within 121.5 km2 of wet meadows treated with 47 g of fenthion (AI) per ha in ultralow- volume formulation. Assessment methods were searches for sick or dead birds, measurements of brain ChE activity in specimens found dead or collected alive at different time intervals, and counts of bird populations. After treatment, 99 birds and 15 mammals were found sick or dead; 106 of these were on one site. Brain ChE activity in dead birds was depressed sufficiently to indicate that death was caused by an anti-ChE substance. Brain ChE activity in three common bird species collected alive showed the greatest reduction 2 days postspray. Two of these species had ChE activity that was still significantly (P<0.05) depressed 15 days postspray. Bird populations declined most where mortality was heaviest. Fenthion sprayed for mosquito control was life threatening to many birds inhabiting treated meadows.

Effect of Zingiber officinale and propolis on microorganisms and endotoxins in root canals

PubMed Central

MAEKAWA, Lilian Eiko; VALERA, Marcia Carneiro; de OLIVEIRA, Luciane Dias; CARVALHO, Cláudio Antonio Talge; CAMARGO, Carlos Henrique Ribeiro; JORGE, Antonio Olavo Cardoso

2013-01-01

The purpose of this study was to evaluate the effectiveness of glycolic propolis (PRO) and ginger (GIN) extracts, calcium hydroxide (CH), chlorhexidine (CLX) gel and their combinations as ICMs (ICMs) against Candida albicans, Enterococcus faecalis, Escherichia coli and endotoxins in root canals. Material and Methods: After 28 days of contamination with microorganisms, the canals were instrumented and then divided according to the ICM: CH+saline; CLX, CH+CLX, PRO, PRO+CH; GIN; GIN+CH; saline. The antimicrobial activity and quantification of endotoxins by the chromogenic test of Limulus amebocyte lysate were evaluated after contamination and instrumentation at 14 days of ICM application and 7 days after ICM removal. Results and Conclusion: After analysis of results and application of the Kruskal-Wallis and Dunn statistical tests at 5% significance level, it was concluded that all ICMs were able to eliminate the microorganisms in the root canals and reduce their amount of endotoxins; however, CH was more effective in neutralizing endotoxins and less effective against C. albicans and E. faecalis, requiring the use of medication combinations to obtain higher success. PMID:23559108

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

PubMed

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).

Relativistic GW calculations on CH3NH3PbI3 and CH3NH3SnI3 Perovskites for Solar Cell Applications

PubMed Central

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

2014-01-01

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(I1−xClx)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). PMID:24667758

In vitro and in vivo co-culture of chondrocytes and bone marrow stem cells in photocrosslinked PCL-PEG-PCL hydrogels enhances cartilage formation.

PubMed

Ko, Chao-Yin; Ku, Kuan-Lin; Yang, Shu-Rui; Lin, Tsai-Yu; Peng, Sydney; Peng, Yu-Shiang; Cheng, Ming-Huei; Chu, I-Ming

2016-10-01

Chondrocytes (CH) and bone marrow stem cells (BMSCs) are sources that can be used in cartilage tissue engineering. Co-culture of CHs and BMSCs is a promising strategy for promoting chondrogenic differentiation. In this study, articular CHs and BMSCs were encapsulated in PCL-PEG-PCL photocrosslinked hydrogels for 4 weeks. Various ratios of CH:BMSC co-cultures were investigated to identify the optimal ratio for cartilage formation. The results thus obtained revealed that co-culturing CHs and BMSCs in hydrogels provides an appropriate in vitro microenvironment for chondrogenic differentiation and cartilage matrix production. Co-culture with a 1:4 CH:BMSC ratio significantly increased the synthesis of GAGs and collagen. In vivo cartilage regeneration was evaluated using a co-culture system in rabbit models. The co-culture system exhibited a hyaline chondrocyte phenotype with excellent regeneration, resembling the morphology of native cartilage. This finding suggests that the co-culture of these two cell types promotes cartilage regeneration and that the system, including the hydrogel scaffold, has potential in cartilage tissue engineering. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

Le Châtelier's conjecture: Measurement of colloidal eigenstresses in chemically reactive materials

NASA Astrophysics Data System (ADS)

Abuhaikal, Muhannad; Ioannidou, Katerina; Petersen, Thomas; Pellenq, Roland J.-M.; Ulm, Franz-Josef

2018-03-01

Volume changes in chemically reactive materials, such as hydrating cement, play a critical role in many engineering applications that require precise estimates of stress and pressure developments. But a means to determine bulk volume changes in the absence of other deformation mechanisms related to thermal, pressure and load variations, is still missing. Herein, we present such a measuring devise, and a hybrid experimental-theoretical technique that permits the determination of colloidal eigenstresses. Applied to cementitious materials, it is found that bulk volume changes in saturated cement pastes at constant pressure and temperature conditions result from a competition of repulsive and attractive phenomena that originate from the relative distance of the solid particles - much as Henry Louis Le Châtelier, the father of modern cement science, had conjectured in the late 19th century. Precipitation of hydration products in confined spaces entails a repulsion, whereas the concurrent reduction in interparticle distance entails activation of attractive forces in charged colloidal particles. This cross-over from repulsion to attraction can be viewed as a phase transition between a liquid state (below the solid percolation) and the limit packing of hard spheres, separated by an energy barrier that defines the temperature-dependent eigenstress magnitude.

Correlation of spatial intensity distribution of light reaching the retina and restoration of vision by optogenetic stimulation

NASA Astrophysics Data System (ADS)

Shivalingaiah, Shivaranjani; Gu, Ling; Mohanty, Samarendra K.

2011-03-01

Stimulation of retinal neuronal cells using optogenetics via use of chanelrhodopsin-2 (ChR2) and blue light has opened up a new direction for restoration of vision with respect to treatment of Retinitis pigmentosa (RP). In addition to delivery of ChR2 to specific retinal layer using genetic engineering, threshold level of blue light needs to be delivered onto the retina for generating action potential and successful behavioral outcome. We report measurement of intensity distribution of light reaching the retina of Retinitis pigmentosa (RP) mouse models and compared those results with theoretical simulations of light propagation in eye. The parameters for the stimulating source positioning in front of eye was determined for optimal light delivery to the retina. In contrast to earlier viral method based delivery of ChR2 onto retinal ganglion cells, in-vivo electroporation method was employed for retina-transfection of RP mice. The behavioral improvement in mice with Thy1-ChR2-YFP transfected retina, expressing ChR2 in retinal ganglion cells, was found to correlate with stimulation intensity.

Experience Gained during the Adaptation of Classical ChE Subjects to the Bologna Plan in Europe: The Case of Chemical Reactors

ERIC Educational Resources Information Center

Ponsa, Sergio; Sanchez, Antoni

2011-01-01

At present, due to the overall adaptation to the European Higher Education Area (EHEA), a new concept regarding the teaching methodology was thought to be essential for engineering subjects. In this paper we describe our experience teaching the altered content of the courses on two classical subjects; Chemical Reactors (Chemical Engineering) and…

Raman spectroscopy measurement of CH4 gas and CH4 dissolved in water for laser remote sensing in water

NASA Astrophysics Data System (ADS)

Somekawa, Toshihiro; Fujita, Masayuki

2018-04-01

We examined the applicability of Raman spectroscopy as a laser remote sensing tool for monitoring CH4 in water. The Raman technique has already been used successfully for measurements of CO2 gas in water. In this paper, considering the spectral transmittance of water, third harmonics of Q-switched Nd:YAG laser at 355 nm (UV region) was used for detection of CH4 Raman signals. The Raman signal at 2892 cm-1 from CH4 dissolved in water was detected at a tail of water Raman signal.

Finishing Systems for Naval Aircraft Applications: Current Schemes and Future Trends

DTIC Science & Technology

2000-01-01

glycidyl ether (CGE) and the difunctional neopentyl glycol , diglycidyl ether (NGDE) are pictured below in Figure 7. 16 o r CH3 OH CH2- XCH-CH2--0-<Q)-C...glycidyl ether (CGE) and neopentyl glycol , diglycidyl ether (NGDE). Coatings prepared with CGE were unacceptable due to poor surface properties and

[Effects of combined applications of pig manure and chemical fertilizers on CH4 and N2O emissions and their global warming potentials in paddy fields with double-rice cropping].

PubMed

Wang, Cong; Shen, Jian-Lin; Zheng, Liang; Liu, Jie-Yun; Qin, Hong-Ling; Li, Yong; Wu, Jin-Shui

2014-08-01

A field experiment was carried out to study the effects of combined applications of pig manure and chemical fertilizers on CH4 and N2O emissions, which were measured using the static chamber/gas chromatography method, and their global warming potentials in typical paddy fields with double-rice cropping in Hunan province. The results showed that the combined applications of pig manure and chemical fertilizers did not change the seasonal patterns of CH4 and N2O emissions from paddy soils, but significantly changed the magnitudes of CH4 and N2O fluxes in rice growing seasons as compared with sole application of chemical fertilizers. During the two rice growing seasons, the cumulative CH4 emissions for the pig manure and chemical nitrogen (N) fertilizer each contributing to 50% of the total applied N (1/2N + PM) treatment were higher than those for the treatments of no N fertilizer (ON), half amount of chemical N fertilizer (1/2N) and 100% chemical N fertilizer (N) by 54.83%, 33.85% and 43.30%, respectively (P < 0.05), whilst the cumulative N2O emissions for the 1/2N + PM treatment were decreased by 67.50% compared with N treatment, but increased by 129.43% and 119.23% compared with ON and 1/2N treatments, respectively (P < 0.05). CH4 was the dominant contributor to the global warming potential (GWP) in both rice growing seasons, which contributed more than 99% to the integrated GWP of CH4 and N2O emissions for all the four treatments. Both GWP and yield-scaled GWP for the treatment of 1/2N + PM were significantly higher than the other three treatments. The yield-scaled GWP for the treatment of 1/2N + PM was higher than those for the N, 1/2N and ON treatments by 58.21%, 26.82% and 20. 63%, respectively. Therefore, combined applications of pig manure and chemical fertilizers in paddy fields would increase the GWP of CH4 and N2O emissions during rice growing seasons and this effect should be considered in regional greenhouse gases emissions inventory.

Immunoglobulin domain interface exchange as a platform technology for the generation of Fc heterodimers and bispecific antibodies.

PubMed

Skegro, Darko; Stutz, Cian; Ollier, Romain; Svensson, Emelie; Wassmann, Paul; Bourquin, Florence; Monney, Thierry; Gn, Sunitha; Blein, Stanislas

2017-06-09

Bispecific antibodies (bsAbs) are of significant importance to the development of novel antibody-based therapies, and heavy chain (Hc) heterodimers represent a major class of bispecific drug candidates. Current technologies for the generation of Hc heterodimers are suboptimal and often suffer from contamination by homodimers posing purification challenges. Here, we introduce a new technology based on biomimicry wherein the protein-protein interfaces of two different immunoglobulin (Ig) constant domain pairs are exchanged in part or fully to design new heterodimeric domains. The method can be applied across Igs to design Fc heterodimers and bsAbs. We investigated interfaces from human IgA CH3, IgD CH3, IgG1 CH3, IgM CH4, T-cell receptor (TCR) α/β, and TCR γ/δ constant domain pairs, and we found that they successfully drive human IgG1 CH3 or IgM CH4 heterodimerization to levels similar to or above those of reference methods. A comprehensive interface exchange between the TCR α/β constant domain pair and the IgG1 CH3 homodimer was evidenced by X-ray crystallography and used to engineer examples of bsAbs for cancer therapy. Parental antibody pairs were rapidly reformatted into scalable bsAbs that were free of homodimer traces by combining interface exchange, asymmetric Protein A binding, and the scFv × Fab format. In summary, we successfully built several new CH3- or CH4-based heterodimers that may prove useful for designing new bsAb-based therapeutics, and we anticipate that our approach could be broadly implemented across the Ig constant domain family. To our knowledge, CH4-based heterodimers have not been previously reported. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

AES based secure low energy adaptive clustering hierarchy for WSNs

NASA Astrophysics Data System (ADS)

Kishore, K. R.; Sarma, N. V. S. N.

2013-01-01

Wireless sensor networks (WSNs) provide a low cost solution in diversified application areas. The wireless sensor nodes are inexpensive tiny devices with limited storage, computational capability and power. They are being deployed in large scale in both military and civilian applications. Security of the data is one of the key concerns where large numbers of nodes are deployed. Here, an energy-efficient secure routing protocol, secure-LEACH (Low Energy Adaptive Clustering Hierarchy) for WSNs based on the Advanced Encryption Standard (AES) is being proposed. This crypto system is a session based one and a new session key is assigned for each new session. The network (WSN) is divided into number of groups or clusters and a cluster head (CH) is selected among the member nodes of each cluster. The measured data from the nodes is aggregated by the respective CH's and then each CH relays this data to another CH towards the gateway node in the WSN which in turn sends the same to the Base station (BS). In order to maintain confidentiality of data while being transmitted, it is necessary to encrypt the data before sending at every hop, from a node to the CH and from the CH to another CH or to the gateway node.

A five-year study of the impact of nitrogen addition on methane uptake in alpine grassland.

PubMed

Yue, Ping; Li, Kaihui; Gong, Yanming; Hu, Yukun; Mohammat, Anwar; Christie, Peter; Liu, Xuejun

2016-08-30

It remains unclear how nitrogen (N) deposition affects soil methane (CH4) uptake in semiarid and arid zones. An in situ field experiment was conducted from 2010 to 2014 to systematically study the effect of various N application rates (0, 10, 30, and 90 kg N ha(-1) yr(-1)) on CH4 flux in alpine grassland in the Tianshan Mountains. No significant influence of N addition on CH4 uptake was found. Initially the CH4 uptake rate increased with increasing N application rate by up to 11.5% in 2011 and then there was gradual inhibition by 2014. However, the between-year variability in CH4 uptake was very highly significant with average uptake ranging from 52.9 to 106.6 μg C m(-2) h(-1) and the rate depended largely on seasonal variability in precipitation and temperature. CH4 uptake was positively correlated with soil temperature, air temperature and to a lesser extent with precipitation, and was negatively correlated with soil moisture and NO3(-)-N content. The results indicate that between-year variability in CH4 uptake was impacted by precipitation and temperature and was not sensitive to elevated N deposition in alpine grassland.

A five-year study of the impact of nitrogen addition on methane uptake in alpine grassland

PubMed Central

Yue, Ping; Li, Kaihui; Gong, Yanming; Hu, Yukun; Mohammat, Anwar; Christie, Peter; Liu, Xuejun

2016-01-01

It remains unclear how nitrogen (N) deposition affects soil methane (CH4) uptake in semiarid and arid zones. An in situ field experiment was conducted from 2010 to 2014 to systematically study the effect of various N application rates (0, 10, 30, and 90 kg N ha−1 yr−1) on CH4 flux in alpine grassland in the Tianshan Mountains. No significant influence of N addition on CH4 uptake was found. Initially the CH4 uptake rate increased with increasing N application rate by up to 11.5% in 2011 and then there was gradual inhibition by 2014. However, the between-year variability in CH4 uptake was very highly significant with average uptake ranging from 52.9 to 106.6 μg C m−2 h−1 and the rate depended largely on seasonal variability in precipitation and temperature. CH4 uptake was positively correlated with soil temperature, air temperature and to a lesser extent with precipitation, and was negatively correlated with soil moisture and NO3−-N content. The results indicate that between-year variability in CH4 uptake was impacted by precipitation and temperature and was not sensitive to elevated N deposition in alpine grassland. PMID:27571892

Band Structure Engineering of Cs2AgBiBr6 Perovskite through Order-Disordered Transition: A First-Principle Study.

PubMed

Yang, Jingxiu; Zhang, Peng; Wei, Su-Huai

2018-01-04

Cs 2 AgBiBr 6 was proposed as one of the inorganic, stable, and nontoxic replacements of the methylammonium lead halides (CH 3 NH 3 PbI 3 , which is currently considered as one of the most promising light-harvesting material for solar cells). However, the wide indirect band gap of Cs 2 AgBiBr 6 suggests that its application in photovoltaics is limited. Using the first-principle calculation, we show that by controlling the ordering parameter at the mixed sublattice, the band gap of Cs 2 AgBiBr 6 can vary continuously from a wide indirect band gap of 1.93 eV for the fully ordered double-perovskite structure to a small pseudodirect band gap of 0.44 eV for the fully random alloy. Therefore, one can achieve better light absorption simply by controlling the growth temperature and thus the ordering parameters and band gaps. We also show that controlled doping in Cs 2 AgBiBr 6 can change the energy difference between ordered and disordered Cs 2 AgBiBr 6 , thus providing further control of the ordering parameters and the band gaps. Our study, therefore, provides a novel approach to carry out band structure engineering in the mixed perovskites for optoelectronic applications.

Recovery of brain and plasma cholinesterase activities in ducklings exposed to organophosphorus pesticides

USGS Publications Warehouse

Fleming, W.J.

1981-01-01

Brain and plasma cholinesterase (ChE) activities were determined for mallard ducklings (Anas platyrhynchos) exposed to dicrotophos and fenthion. Recovery rates of brain ChE did not differ between ducklings administered a single oral dose vs. a 2-week dietary dose of these organophosphates. Exposure to the organophosphates, followed by recovery of brain ChE, did not significantly affect the degree of brain ChE inhibition or the recovery of ChE activity at a subsequent exposure. Recovery of brain ChE activity followed the general model Y = a + b(logX) with rapid recovery to about 50% of normal, followed by a slower rate of recovery until normal ChE activity levels were attained. Fenthion and dicrotophos-inhibited brain ChE were only slightly reactivated in vitro by pyridine-2-aldoxime methiodide, which suggested that spontaneous reactivation was not a primary method of recovery of ChE activity. Recovery of brain ChE activity can be modeled for interpretation of sublethal inhibition of brain ChE activities in wild birds following environmental applications of organophosphates. Plasma ChE activity is inferior to brain ChE activity for environmental monitoring, because of its rapid recovery and large degree of variation among individuals.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Study of the subpicosecond rotational molecular dynamics in liquids

NASA Astrophysics Data System (ADS)

Nikiforov, V. G.; Lobkov, Vladimir S.

2006-10-01

The parameters of the femtosecond vibration—rotation molecular dynamics of liquid acetonitrile CH3CN, trimethylacetonitrile (CH3)3CCN, propionitrile CH3CH2CN, fluoroform CHF3, and chloroform CHCl3 are found by analysing the ultrafast optical Kerr effect. The influence of the molecular structure on the features of rotational (diffusion and libration) motions is studied. It is shown that the distribution of libration frequencies is described by the Maxwell distribution.

75 FR 10299 - Revision to Navigation and Inspection Circular 11-93, Change 3 (NVIC 11-93 CH-3), Applicability...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-05

... Inspection Circular 11-93, Change 3 (NVIC 11-93 CH-3), Applicability of Tonnage Measurement Systems to U.S. Flag Vessels AGENCY: Coast Guard, DHS. ACTION: Notice of policy revision and request for comments... Systems to U.S. Flag Vessels to update the document and improve its usefulness. We are seeking public...

Membrane protein resistance of oligo(ethylene oxide) self-assembled monolayers.

PubMed

Vaish, Amit; Vanderah, David J; Vierling, Ryan; Crawshaw, Fay; Gallagher, D Travis; Walker, Marlon L

2014-10-01

As part of an effort to develop biointerfaces for structure-function studies of integral membrane proteins (IMPs) a series of oligo(ethylene oxide) self-assembled monolayers (OEO-SAMs) were evaluated for their resistance to protein adsorption (RPA) of IMPs on Au and Pt. Spectroscopic ellipsometry (SE) was used to determine SAM thicknesses and compare the RPA of HS(CH2)3O(CH2CH2O)6CH3 (1), HS(CH2)3O(CH2CH2O)6H (2), [HS(CH2)3]2CHO(CH2CH2O)6CH3 (3) and [HS(CH2)3]2CHO(CH2CH2O)6H (4), assembled from water. For both substrates, SAM thicknesses for 1 to 4 were found to be comparable indicating SAMs with similar surface coverages and OEO chain order and packing densities. Fibrinogen (Fb), a soluble plasma protein, and rhodopsin (Rd), an integral membrane G-protein coupled receptor, adsorbed to the SAMs of 1, as expected from previous reports, but not to the hydroxy-terminated SAMs of 2 and 4. The methoxy-terminated SAMs of 3 were resistant to Fb but, surprisingly, not to Rd. The stark difference between the adsorption of Rd to the SAMs of 3 and 4 clearly indicate that a hydroxy-terminus of the OEO chain is essential for high RPA of IMPs. The similar thicknesses and high RPA of the SAMs of 2 and 4 show the conditions of protein resistance (screening the underlying substrate, packing densities, SAM order, and conformational mobility of the OEO chains) defined from previous studies on Au are applicable to Pt. In addition, the SAMs of 4, exhibiting the highest resistance to Fb and Rd, were placed in contact with undiluted fetal bovine serum for 2h. Low protein adsorption (≈12.4ng/cm(2)), obtained under these more challenging conditions, denote a high potential of the SAMs of 4 for various applications requiring the suppression of non-specific protein adsorption. Published by Elsevier B.V.

Enzymatic Functionalization of Carbon-Hydrogen Bonds1

PubMed Central

Lewis, Jared C.; Coelho, Pedro S.

2010-01-01

The development of new catalytic methods to functionalize carbon-hydrogen (C-H) bonds continues to progress at a rapid pace due to the significant economic and environmental benefits of these transformations over traditional synthetic methods. In nature, enzymes catalyze regio- and stereoselective C-H bond functionalization using transformations ranging from hydroxylation to hydroalkylation under ambient reaction conditions. The efficiency of these enzymes relative to analogous chemical processes has led to their increased use as biocatalysts in preparative and industrial applications. Furthermore, unlike small molecule catalysts, enzymes can be systematically optimized via directed evolution for a particular application and can be expressed in vivo to augment the biosynthetic capability of living organisms. While a variety of technical challenges must still be overcome for practical application of many enzymes for C-H bond functionalization, continued research on natural enzymes and on novel artificial metalloenzymes will lead to improved synthetic processes for efficient synthesis of complex molecules. In this critical review, we discuss the most prevalent mechanistic strategies used by enzymes to functionalize non-acidic C-H bonds, the application and evolution of these enzymes for chemical synthesis, and a number of potential biosynthetic capabilities uniquely enabled by these powerful catalysts. PMID:21079862

High Temperature Superconducting Compounds

DTIC Science & Technology

1992-11-30

broadened interest in superconductivity in both the engineering and scientific communities. Superconducting materials may be offered as a solution to a...YBa2Cu307- has been made. For yttrium, the tris( isopropoxide ) was used exclusively, while the use of both Ba(O-i-Pr)2 and Ba(OCH2Ch2OEt)2 (prepared in... solutions of Cu(acac)2, Ba(OCH2CH 2OEt)2 , and Y(O-i-Pr)3 were spin coated on SrTiO 3 (100) and fired under oxygen to give oriented (b axis normal to the

IRIG 106 Chapter 10 Programmers Handbook

DTIC Science & Technology

2016-08-16

card number that controls the desired SCSI device. When 10 Internet Engineering Task Force...idmptmat - Read and dump a TMATS record from an IRIG 106 Ch 10 data file Copyright (c) 2006 Irig106.org All rights reserved

ChE at the Erevan Polytechnic Institute Soviet Armenia.

ERIC Educational Resources Information Center

Hanesian, Deran

1984-01-01

Provides background information on Soviet Armenia and the Erevan Polytechnic Institute (EPI) located in this republic of the USSR. Also provides a description of chemical engineering programs and courses and faculty at the EPI. (JN)

Light-controlled inhibition of malignant glioma by opsin gene transfer

PubMed Central

Yang, F; Tu, J; Pan, J-Q; Luo, H-L; Liu, Y-H; Wan, J; Zhang, J; Wei, P-F; Jiang, T; Chen, Y-H; Wang, L-P

2013-01-01

Glioblastomas are aggressive cancers with low survival rates and poor prognosis because of their highly proliferative and invasive capacity. In the current study, we describe a new optogenetic strategy that selectively inhibits glioma cells through light-controlled membrane depolarization and cell death. Transfer of the engineered opsin ChETA (engineered Channelrhodopsin-2 variant) gene into primary human glioma cells or cell lines, but not normal astrocytes, unexpectedly decreased cell proliferation and increased mitochondria-dependent apoptosis, upon light stimulation. These optogenetic effects were mediated by membrane depolarization-induced reductions in cyclin expression and mitochondrial transmembrane potential. Importantly, the ChETA gene transfer and light illumination in mice significantly inhibited subcutaneous and intracranial glioma growth and increased the survival of the animals bearing the glioma. These results uncover an unexpected effect of opsin ion channels on glioma cells and offer the opportunity for the first time to treat glioma using a light-controllable optogenetic approach. PMID:24176851

Exploiting and engineering hemoproteins for abiological carbene and nitrene transfer reactions.

PubMed

Brandenberg, Oliver F; Fasan, Rudi; Arnold, Frances H

2017-10-01

The surge in reports of heme-dependent proteins as catalysts for abiotic, synthetically valuable carbene and nitrene transfer reactions dramatically illustrates the evolvability of the protein world and our nascent ability to exploit that for new enzyme chemistry. We highlight the latest additions to the hemoprotein-catalyzed reaction repertoire (including carbene Si-H and C-H insertions, Doyle-Kirmse reactions, aldehyde olefinations, azide-to-aldehyde conversions, and intermolecular nitrene C-H insertion) and show how different hemoprotein scaffolds offer varied reactivity and selectivity. Preparative-scale syntheses of pharmaceutically relevant compounds accomplished with these new catalysts are beginning to demonstrate their biotechnological relevance. Insights into the determinants of enzyme lifetime and product yield are providing generalizable cues for engineering heme-dependent proteins to further broaden the scope and utility of these non-natural activities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Light-controlled inhibition of malignant glioma by opsin gene transfer.

PubMed

Yang, F; Tu, J; Pan, J-Q; Luo, H-L; Liu, Y-H; Wan, J; Zhang, J; Wei, P-F; Jiang, T; Chen, Y-H; Wang, L-P

2013-10-31

Glioblastomas are aggressive cancers with low survival rates and poor prognosis because of their highly proliferative and invasive capacity. In the current study, we describe a new optogenetic strategy that selectively inhibits glioma cells through light-controlled membrane depolarization and cell death. Transfer of the engineered opsin ChETA (engineered Channelrhodopsin-2 variant) gene into primary human glioma cells or cell lines, but not normal astrocytes, unexpectedly decreased cell proliferation and increased mitochondria-dependent apoptosis, upon light stimulation. These optogenetic effects were mediated by membrane depolarization-induced reductions in cyclin expression and mitochondrial transmembrane potential. Importantly, the ChETA gene transfer and light illumination in mice significantly inhibited subcutaneous and intracranial glioma growth and increased the survival of the animals bearing the glioma. These results uncover an unexpected effect of opsin ion channels on glioma cells and offer the opportunity for the first time to treat glioma using a light-controllable optogenetic approach.

Tribology of Ceramics. Report of the Committee on Tribology of Ceramics.

DTIC Science & Technology

1988-01-01

lt, Mat Iri t I S ,ne,i’-ch So ijet, and a Fe 1 low of the Ai’ h’ c P "lc; i". ...oi .... It S H 1- .S deHt11e in chemical engineering is from Vi...Committee on Tribology of Ceramics NATIONAL MATERIALS ADVISORY BOARD Commission on Engineering and Technical Systems National Research Council DTIC...the councils ot he National Academy of Sciences, the National Academy of Engineering , and the Institute Medicine. The members of the committee

Pavement-Transportation Computer Assisted Structural Engineering (PCASE) Implementation of the Modified Berggren (ModBerg) Equation for Computing the Frost Penetration Depth within Pavement Structures

DTIC Science & Technology

2012-04-01

ER D C/ G SL T R -1 2 -1 5 Pavement -Transportation Computer Assisted Structural Engineering (PCASE) Implementation of the Modified...Berggren (ModBerg) Equation for Computing the Frost Penetration Depth within Pavement Structures G eo te ch n ic al a n d S tr u ct u re s La b or at...April 2012 Pavement -Transportation Computer Assisted Structural Engineering (PCASE) Implementation of the Modified Berggren (ModBerg) Equation for

2D Homologous Perovskites as Light-Absorbing Materials for Solar Cell Applications.

PubMed

Cao, Duyen H; Stoumpos, Constantinos C; Farha, Omar K; Hupp, Joseph T; Kanatzidis, Mercouri G

2015-06-24

We report on the fabrication and properties of the semiconducting 2D (CH3(CH2)3NH3)2(CH3NH3)(n-1)Pb(n)I(3n+1) (n = 1, 2, 3, and 4) perovskite thin films. The band gaps of the series decrease with increasing n values, from 2.24 eV (CH3(CH2)3NH3)2PbI4 (n = 1) to 1.52 eV CH3NH3PbI3 (n = ∞). The compounds exhibit strong light absorption in the visible region, accompanied by strong photoluminescence at room temperature, rendering them promising light absorbers for photovoltaic applications. Moreover, we find that thin films of the semi-2D perovskites display an ultrahigh surface coverage as a result of the unusual film self-assembly that orients the [Pb(n)I(3n+1)](-) layers perpendicular to the substrates. We have successfully implemented this 2D perovskite family in solid-state solar cells, and obtained an initial power conversion efficiency of 4.02%, featuring an open-circuit voltage (V(oc)) of 929 mV and a short-circuit current density (J(sc)) of 9.42 mA/cm(2) from the n = 3 compound. This result is even more encouraging considering that the device retains its performance after long exposure to a high-humidity environment. Overall, the homologous 2D halide perovskites define a promising class of stable and efficient light-absorbing materials for solid-state photovoltaics and other applications.

Photoemission Spectroscopy Studies of Methylammonium Lead Iodide Perovskite Thin Films and Interfaces

NASA Astrophysics Data System (ADS)

Thibau, Emmanuel S.

Organometal halide perovskites have recently emerged as promising materials for fundamentally low-cost, high-performance optoelectronics. In this thesis, we utilize thermal co-evaporation of PbI2 and CH3NH 3 I to fabricate thin films of CH3NH3PbI 3. We first investigate the effect of stoichiometry on some of its structural, optical and electronic properties. Then, we study the energy level alignment of CH3NH3PbI3 with 6 organic semiconductors, revealing good agreement between the data and the theory of vacuum level alignment. Finally, the interface formed between CH3NH 3PbI3 and MoO3 is examined. The findings suggest migration of iodide species into the oxide layer, resulting in deterioration of its chemical and electronic properties. Insertion of an organic interlayer is shown to mitigate these undesirable effects. The results of this work could be of use in device engineering, where knowledge of such interfacial phenomena is of utmost importance in achieving optimized device structures.

Sensitive, Site-Specific, and Stable Vibrational Probe of Local Protein Environments: 4-Azidomethyl-L-Phenylalanine

PubMed Central

Bazewicz, Christopher G.; Liskov, Melanie T.; Hines, Kevin J.; Brewer, Scott H.

2013-01-01

We have synthesized the unnatural amino acid (UAA), 4-azidomethyl-Lphenylalanine (pN3CH2Phe), to serve as an effective vibrational reporter of local protein environments. The position, extinction coefficient, and sensitivity to local environment of the azide asymmetric stretch vibration of pN3CH2Phe are compared to the vibrational reporters: 4-cyano-L-phenylalanine (pCNPhe) and 4-azido-L-phenylalanine (pN3Phe). This UAA was genetically incorporated in a site-specific manner utilizing an engineered, orthogonal aminoacyl-tRNA synthetase in response to an amber codon with high efficiency and fidelity into two distinct sites in superfolder green fluorescent protein (sfGFP). This allowed for the dependence of the azide asymmetric stretch vibration of pN3CH2Phe to different protein environments to be measured. The photo-stability of pN3CH2Phe was also measured relative to the photoreactive UAA, pN3Phe. PMID:23865850

Hyperfine excitation of CH in collisions with atomic and molecular hydrogen

NASA Astrophysics Data System (ADS)

Dagdigian, Paul J.

2018-04-01

We investigate here the excitation of methylidene (CH) induced by collisions with atomic and molecular hydrogen (H and H2). The hyperfine-resolved rate coefficients were obtained from close coupling nuclear-spin-free scattering calculations. The calculations are based upon recent, high-accuracy calculations of the CH(X2Π)-H(2S) and CH(X2Π)-H2 potential energy surfaces. Cross-sections and rate coefficients for collisions with atomic H, para-H2, and ortho-H2 were computed for all transitions between the 32 hyperfine levels for CH(X2Π) involving the n ≤ 4 rotational levels for temperatures between 10 and 300 K. These rate coefficients should significantly aid in the interpretation of astronomical observations of CH spectra. As a first application, the excitation of CH is simulated for conditions in typical molecular clouds.

Synergistic Heterobimetallic Manifold for Expedient Manganese(I)-Catalyzed C-H Cyanation.

PubMed

Liu, Weiping; Richter, Sven C; Mei, Ruhuai; Feldt, Milica; Ackermann, Lutz

2016-12-12

The manganese-catalyzed cyanation of inert C-H bonds was achieved within a heterobimetallic catalysis regime. The manganese(I) catalysis proved widely applicable and enabled C-H cyanations on indoles, pyrroles and thiophenes by facile C-H manganesation. The robustness of the manganese catalyst set the stage for the racemization-free C-H cyanation of amino acids with excellent levels of positional and chemo selectivity by the new cyanating agent NCFS. Experimental and computational mechanistic studies provided strong support for a synergistic heterobimetallic activation mode, facilitating the key C-C formation. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advanced Reciprocating Engine Systems (ARES) Research at Argonne National Laboratory. A Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Sreenath; Biruduganti, Muni; Bihari, Bipin

The goals of these experiments were to determine the potential of employing spectral measurements to deduce combustion metrics such as HRR, combustion temperatures, and equivalence ratios in a natural gas-fired reciprocating engine. A laser-ignited, natural gas-fired single-cylinder research engine was operated at various equivalence ratios between 0.6 and 1.0, while varying the EGR levels between 0% and maximum to thereby ensure steady combustion. Crank angle-resolved spectral signatures were collected over 266-795 nm, encompassing chemiluminescence emissions from OH*, CH*, and predominantly by CO2* species. Further, laser-induced gas breakdown spectra were recorded under various engine operating conditions.

Production and characterization of active recombinant interleukin-12/eGFP fusion protein in stably-transfected DF1 chicken cells.

PubMed

Wu, Hsing Chieh; Chen, Yu San; Shen, Pin Chun; Shien, Jui Hung; Lee, Long Huw; Chiu, Hua Hsien

2015-01-01

The adjuvant activity of chicken interleukin-12 (chIL-12) protein has been described as similar to that of mammalian IL-12. Recombinant chIL-12 can be produced using several methods, but chIL-12 production in eukaryotic cells is lower than that in prokaryotic cells. Stimulating compounds, such as dimethyl sulfoxide (DMSO), can be added to animal cell cultures to overcome this drawback. In this study, we constructed a cell line, DF1/chIL-12 which stably expressed a fusion protein, chIL-12 and enhanced green fluorescent protein (eGFP) connected by a (G4 S)3 linker sequence. Fusion protein production was increased when cells were cultured in the presence of DMSO. When 1 × 10(6) DF1/chIL-12 cells were inoculated in a T-175 flask containing 30 mL of media, incubated for 15 h, and further cultivated in the presence of 4% DMSO for 48 h, the production of total fusion protein was mostly enhanced compared with the production of total fusion protein by using cell lysates induced with DMSO at other concentrations. The concentrations of the unpurified and purified total fusion proteins in cell lysates were 2,781 ± 2.72 ng mL(-1) and 2,207 ± 3.28 ng mL(-1) , respectively. The recovery rate was 79%. The fusion protein stimulated chicken splenocytes to produce IFN-γ, which was measured using an enzyme-linked immunosorbent assay, in the culture supernatant, indicating that treating DF1/chIL-12 cells with DMSO or producing chIL-12 in a fusion protein form does not have adverse effects on the bioactivity of chIL-12. © 2015 American Institute of Chemical Engineers.

Introducing Students to Basic ChE Concepts: Four Simple Experiments.

ERIC Educational Resources Information Center

Fraser, Duncan M.

1999-01-01

Describes an Introduction to Chemical Engineering course with particular reference to the development, use, and evaluation of four simple experiments centered around the fundamental principles of heat transfer, mass transfer, reaction kinetics, and momentum transfer. (WRM)

40 CFR 1036.501 - How do I run a valid emission test?

Code of Federal Regulations, 2013 CFR

2013-07-01

... aftertreatment technology with infrequent regeneration events, invalidate any test interval in which such a regeneration event occurs with respect to CO2, N2O, and CH4 measurements. (e) Test hybrid engines as described...

40 CFR 1036.501 - How do I run a valid emission test?

Code of Federal Regulations, 2012 CFR

2012-07-01

... aftertreatment technology with infrequent regeneration events, invalidate any test interval in which such a regeneration event occurs with respect to CO2, N2O, and CH4 measurements. (e) Test hybrid engines as described...

40 CFR 1036.501 - How do I run a valid emission test?

Code of Federal Regulations, 2014 CFR

2014-07-01

... aftertreatment technology with infrequent regeneration events, invalidate any test interval in which such a regeneration event occurs with respect to CO2, N2O, and CH4 measurements. (e) Test hybrid engines as described...

40 CFR 85.525 - Applicable standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... results from the emission data vehicle (EDV) representing the pre-conversion test group. The sum of CO2, CH4, and N2O shall be calculated for pre- and post-conversion FTP test results, where CH4 and N2O are..., and N2O shall be calculated for pre- and post-conversion FTP test results, where CH4 and N2O are...

Performance of polydimethylsiloxane membrane contactor process for selective hydrogen sulfide removal from biogas.

PubMed

Tilahun, Ebrahim; Bayrakdar, Alper; Sahinkaya, Erkan; Çalli, Bariş

2017-03-01

H 2 S in biogas affects the co-generation performance adversely by corroding some critical components within the engine and it has to be removed in order to improve the biogas quality. This work presents the use of polydimethylsiloxane (PDMS) membrane contactor for selective removal of H 2 S from the biogas. Experiments were carried out to evaluate the effects of different pH of absorption liquid, biogas flowrate and temperature on the absorption performances. The results revealed that at the lowest loading rate (91mg H 2 S/m 2 ·h) more than 98% H 2 S and 59% CO 2 absorption efficiencies were achieved. The CH 4 content in the treated gas increased from 60 to 80% with nearly 5% CH 4 loss. Increasing the pH (7-10) and loading rate (91-355mg H 2 S/m 2 ·h) enhanced the H 2 S absorption capacity, and the maximum H 2 S/CO 2 and H 2 S/CH 4 selectivity factors were 2.5 and 58, respectively. Temperature played a key role in the process and lower temperature was beneficial for intensifying H 2 S absorption performance. The highest H 2 S fluxes at pH 10 and 7 were 3.4g/m 2 ·d and 1.8g/m 2 ·d with overall mass transfer coefficients of 6.91×10 -6 and 4.99×10 -6 m/s, respectively. The results showed that moderately high H 2 S fluxes with low CH 4 loss may be achieved by using a robust and cost-effective membrane based absorption process for desulfurization of biogas. A tubular PDMS membrane contactor was tested for the first time to remove H 2 S from biogas under slightly alkaline conditions and the suggested process could be a promising for real scale applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Abnormal Current–Voltage Hysteresis Induced by Reverse Bias in Organic–Inorganic Hybrid Perovskite Photovoltaics

DOE PAGES

Rajagopal, Adharsh; Williams, Spencer T.; Chueh, Chu-Chen; ...

2016-02-29

In this study, reverse bias (RB)-induced abnormal hysteresis is investigated in perovskite solar cells (PVSCs) with nickel oxide (NiOx)/methylammonium lead iodide (CH 3NH 3PbI 3) interfaces. Through comprehensive current-voltage (I-V) characterization and bias-dependent external quantum efficiency (EQE) measurements, we demonstrate that this phenomenon is caused by the interfacial ion accumulation intrinsic to CH 3NH 3PbI 3. Subsequently, via systematic analysis we discover that the abnormal I-V behavior is remarkably similar to tunnel diode I-V characteristics and is due to the formation of a transient tunnel junction at NiO x/CH 3NH 3PbI 3 interfaces under RB. The detailed analysis navigating themore » complexities of I-V behavior in CH 3NH 3PbI 3-based solar cells provided here ultimately illuminates possibilities in modulating ion motion and hysteresis via interfacial engineering in PVSCs. Moreover, this work shows that RB can alter how CH 3NH 3PbI 3 contributes to the functional nature of devices and provides the first steps toward approaching functional perovskite interfaces in new ways for metrology and analysis of complex transient processes.« less

Partial Hydrothermal Oxidation of High Molecular Weight Unsaturated Carboxylic Acids for Upgrading of Biodiesel Fuel

NASA Astrophysics Data System (ADS)

Kawasaki, K.; Jin, F.; Kishita, A.; Tohji, K.; Enomoto, H.

2007-03-01

With increasing environmental awareness and crude oil price, biodiesel fuel (BDF) is gaining recognition as a renewable fuel which may be used as an alternative diesel fuel without any modification to the engine. The cold flow and viscosity of BDF, however, is a major drawback that limited its use in cold area. In this study, therefore, we investigated that partial oxidation of high molecular weight unsaturated carboxylic acids in subcritical water, which major compositions in BDF, to upgrade biodiesel fuel. Oleic acid, (HOOC(CH2)7CH=CH(CH2)7CH3), was selected as a model compound of high molecular weight unsaturated carboxylic acids. All experiments were performed with a batch reactor made of SUS 316 with an internal volume of 5.7 cm3. Oleic acid was oxidized at 300 °C with oxygen supply varying from 1-10 %. Results showed that a large amount of carboxylic acids and aldehydes having 8-9 carbon atoms were formed. These experimental results suggest that the hydrothermal oxidative cleavage may mainly occur at double bonds and the cleavage of double bonds could improve the cold flow and viscosity of BDF.

Engineering Aerodynamics

DTIC Science & Technology

1986-12-01

effective Reynolds Number5 to include the effet Of turbulence, which was supported in a convincing manner by the same ratio of 2.4 betwveen the Reynolds...iLIFT DEVICIS 143 methods incorl)orating various forms of flas) are shown on Figure 59. The other two methods, Boundary Layer Control and the Magnus ...Class Airship Hlull with Varying Lengths of Cylindric Midships," N.A.CA. Technical Report No. 138 (1922). 276 ENGINEERING AERODYNAMICS [Ch. 9 -- - - 2.0

Understanding the role of thiol and disulfide self-assembled DNA receptor monolayers for biosensing applications.

PubMed

Carrascosa, Laura G; Martínez, Lidia; Huttel, Yves; Román, Elisa; Lechuga, Laura M

2010-09-01

A detailed study of the immobilization of three differently sulfur-modified DNA receptors for biosensing applications is presented. The three receptors are DNA-(CH)n-SH-, DNA-(CH)n-SS-(CH)n-DNA, and DNA-(CH)n-SS-DMTO. Nanomechanical and surface plasmon resonance biosensors and fluorescence and radiolabelling techniques were used for the experimental evaluation. The results highlight the critical role of sulfur linker type in DNA self-assembly, affecting the kinetic adsorption and spatial distribution of DNA chains within the monolayer and the extent of chemisorption and physisorption. A spacer (mercaptohexanol, MCH) is used to evaluate the relative efficiencies of chemisorption of the three receptors by analysing the extent to which MCH can remove physisorbed molecules from each type of monolayer. It is demonstrated that -SH derivatization is the most suitable for biosensing purposes as it results in densely packed monolayers with the lowest ratio of physisorbed probes.

Simulated nitrogen deposition reduces CH4 uptake and increases N2O emission from a subtropical plantation forest soil in southern China.

PubMed

Wang, Yongsheng; Cheng, Shulan; Fang, Huajun; Yu, Guirui; Xu, Minjie; Dang, Xusheng; Li, Linsen; Wang, Lei

2014-01-01

To date, few studies are conducted to quantify the effects of reduced ammonium (NH4+) and oxidized nitrate (NO3-) on soil CH4 uptake and N2O emission in the subtropical forests. In this study, NH4Cl and NaNO3 fertilizers were applied at three rates: 0, 40 and 120 kg N ha(-1) yr(-1). Soil CH4 and N2O fluxes were determined twice a week using the static chamber technique and gas chromatography. Soil temperature and moisture were simultaneously measured. Soil dissolved N concentration in 0-20 cm depth was measured weekly to examine the regulation to soil CH4 and N2O fluxes. Our results showed that one year of N addition did not affect soil temperature, soil moisture, soil total dissolved N (TDN) and NH4+-N concentrations, but high levels of applied NH4Cl and NaNO3 fertilizers significantly increased soil NO3(-)-N concentration by 124% and 157%, respectively. Nitrogen addition tended to inhibit soil CH4 uptake, but significantly promoted soil N2O emission by 403% to 762%. Furthermore, NH4+-N fertilizer application had a stronger inhibition to soil CH4 uptake and a stronger promotion to soil N2O emission than NO3(-)-N application. Also, both soil CH4 and N2O fluxes were driven by soil temperature and moisture, but soil inorganic N availability was a key integrator of soil CH4 uptake and N2O emission. These results suggest that the subtropical plantation soil sensitively responses to atmospheric N deposition, and inorganic N rather than organic N is the regulator to soil CH4 uptake and N2O emission.

Contribution of rice straw carbon to CH4 emission from rice paddies using 13C-enriched rice straw

NASA Astrophysics Data System (ADS)

Watanabe, Akira; Yoshida, Mariko; Kimura, Makoto

1998-04-01

It is generally recognized that the application of rice straw (RS) increases CH4 emission from rice paddies. To estimate the contribution of RS carbon to CH4 emission, a pot experiment was conducted using 13C-enriched RS. The percentage contributions of RS carbon to CH4 emission throughout the rice growth period were 10±1, 32±3, and 43±3% for the treatments with RS applied at the rates of 2, 4, and 6 g kg-1 soil, respectively. The increase in the rate of application of RS increased CH4 emission derived from both RS carbon and other carbon sources. The percentage contribution of RS carbon to CH4 emission was larger in the earlier period (maximum 96%) when the decomposition rate of RS was larger. After RS decomposition had slowed, CH4 emission derived from RS carbon decreased. However, the δ13C values of CH4 emitted from the pots with 13C-enriched RS applied at rates of 4 and 6 g kg-1 soil were significantly higher than those from the pots with natural RS until the harvesting stage. An increased atom-13C% of roots of rice plants growing in the pots with 6 g kg-1 of 13C-enriched RS at around the maximum tiller number stage and a decrease during the following 2 months suggested that rice plants assimilated RS carbon once and then released a portion of it. This supply of RS carbon from roots may be one of the sources of CH4 in the late period of rice growth.

Inhibitory effects of Citrus hassaku extract and its flavanone glycosides on melanogenesis.

PubMed

Itoh, Kimihisa; Hirata, Noriko; Masuda, Megumi; Naruto, Shunsuke; Murata, Kazuya; Wakabayashi, Keitaro; Matsuda, Hideaki

2009-03-01

The 50% ethanolic extract (CH-ext) obtained from the unripe fruit of Citrus hassaku exhibited significant tyrosinase inhibitory activity. The CH-ext showed antioxidant activity, such as superoxide dismutase (SOD)-like activity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. Activity-guided fractionation of the CH-ext indicated that flavanone glycoside-rich fractions showed potent tyrosinase inhibitory activity. Further examination revealed that the tyrosinase inhibitory activity and antioxidant activity of the CH-ext were attributable to naringin and neohesperidin, respectively. The CH-ext showed inhibition of melanogenesis without any effects on cell proliferation in cultured murine B16 melanoma cells after glucosamine exposure. The topical application of the CH-ext to the dorsal skin of brownish guinea pigs showed in vivo preventive effects against UVB-induced pigmentation.

Twin defects engineered Pd cocatalyst on C3N4 nanosheets for enhanced photocatalytic performance in CO2 reduction reaction

NASA Astrophysics Data System (ADS)

Lang, Qingqing; Hu, Wenli; Zhou, Penghui; Huang, Tianlong; Zhong, Shuxian; Yang, Lining; Chen, Jianrong; Bai, Song

2017-12-01

Photocatalytic conversion of CO2 to value-added chemicals, a potential route to addressing the depletion of fossil fuels and anthropogenic climate change, is greatly limited by the low-efficient semiconductor photocatalyst. The integration of cocatalyst with light-harvesting semiconductor is a promising approach to enhancing the photocatalytic performance in CO2 reduction reaction. The enhancement is greatly determined by the catalytic active sites on the surface of cocatalyst. Herein, we demonstrate that the photocatalytic performance in the CO2 reduction reaction is greatly promoted by twin defects engineered Pd cocatalyst. In this work, Pd nanoicosahedrons with twin defects were in situ grown on C3N4 nanosheets, which effectively improve the photocatalytic performance in reduction of CO2 to CO and CH4 in comparison with Pd nanotetrahedrons without twin defects. It is proposed that the twin boundary (TB) terminations on the surface of Pd cocatalysts are highly catalytic active sites for CO2 reduction reaction. Based on the proposed mechanism, the photocatalytic activity and selectivity in CO2 reduction were further advanced through reducing the size of Pd icosahedral cocatalyst resulted from the increased surface density of TB terminations. The defect engineering on the surface of cocatalyst represents a novel route in realizing high-performance photocatalytic applications.

Calculation of Free-Atom Fractions in Hydrocarbon-Fueled Rocket Engine Plume

NASA Technical Reports Server (NTRS)

Verma, Satyajit

2006-01-01

Free atom fractions (Beta) of nine elements are calculated in the exhaust plume of CH4- oxygen and RP-1-oxygen fueled rocket engines using free energy minimization method. The Chemical Equilibrium and Applications (CEA) computer program developed by the Glenn Research Center, NASA is used for this purpose. Data on variation of Beta in both fuels as a function of temperature (1600 K - 3100 K) and oxygen to fuel ratios (1.75 to 2.25 by weight) is presented in both tabular and graphical forms. Recommendation is made for the Beta value for a tenth element, Palladium. The CEA computer code was also run to compare with experimentally determined Beta values reported in literature for some of these elements. A reasonable agreement, within a factor of three, between the calculated and reported values is observed. Values reported in this work will be used as a first approximation for pilot rocket engine testing studies at the Stennis Space Center for at least six elements Al, Ca, Cr, Cu, Fe and Ni - until experimental values are generated. The current estimates will be improved when more complete thermodynamic data on the remaining four elements Ag, Co, Mn and Pd are added to the database. A critique of the CEA code is also included.

Twin defects engineered Pd cocatalyst on C3N4 nanosheets for enhanced photocatalytic performance in CO2 reduction reaction.

PubMed

Lang, Qingqing; Hu, Wenli; Zhou, Penghui; Huang, Tianlong; Zhong, Shuxian; Yang, Lining; Chen, Jianrong; Bai, Song

2017-12-01

Photocatalytic conversion of CO 2 to value-added chemicals, a potential route to addressing the depletion of fossil fuels and anthropogenic climate change, is greatly limited by the low-efficient semiconductor photocatalyst. The integration of cocatalyst with light-harvesting semiconductor is a promising approach to enhancing the photocatalytic performance in CO 2 reduction reaction. The enhancement is greatly determined by the catalytic active sites on the surface of cocatalyst. Herein, we demonstrate that the photocatalytic performance in the CO 2 reduction reaction is greatly promoted by twin defects engineered Pd cocatalyst. In this work, Pd nanoicosahedrons with twin defects were in situ grown on C 3 N 4 nanosheets, which effectively improve the photocatalytic performance in reduction of CO 2 to CO and CH 4 in comparison with Pd nanotetrahedrons without twin defects. It is proposed that the twin boundary (TB) terminations on the surface of Pd cocatalysts are highly catalytic active sites for CO 2 reduction reaction. Based on the proposed mechanism, the photocatalytic activity and selectivity in CO 2 reduction were further advanced through reducing the size of Pd icosahedral cocatalyst resulted from the increased surface density of TB terminations. The defect engineering on the surface of cocatalyst represents a novel route in realizing high-performance photocatalytic applications.

Carbon-Hydrogen (C-H) Bond Activation at PdIV: A Frontier in C-H Functionalization Catalysis.

PubMed

Topczewski, Joseph J; Sanford, Melanie S

2015-01-01

The direct functionalization of carbon-hydrogen (C-H) bonds has emerged as a versatile strategy for the synthesis and derivatization of organic molecules. Among the methods for C-H bond activation, catalytic processes that utilize a Pd II /Pd IV redox cycle are increasingly common. The C-H activation step in most of these catalytic cycles is thought to occur at a Pd II centre. However, a number of recent reports have suggested the feasibility of C-H cleavage occurring at Pd IV complexes. Importantly, these latter processes often result in complementary reactivity and selectivity relative to analogous transformations at Pd II . This Mini Review highlights proposed examples of C-H activation at Pd IV centres. Applications of this transformation in catalysis as well as mechanistic details obtained from stoichiometric model studies are discussed. Furthermore, challenges and future perspectives for the field are reviewed.

Validation of a Brief Structured Interview: The Children's Interview for Psychiatric Syndromes (ChIPS).

PubMed

Young, Matthew E; Bell, Ziv E; Fristad, Mary A

2016-12-01

Evidence-based assessment is important in the treatment of childhood psychopathology. While researchers and clinicians frequently use structured diagnostic interviews to ensure reliability, the most commonly used instrument, the Schedule for Affective Disorders and Schizophrenia for School Aged Children (K-SADS) is too long for most clinical applications. The Children's Interview for Psychiatric Syndromes (ChIPS/P-ChIPS) is a highly-structured brief diagnostic interview. The present study compared K-SADS and ChIPS/P-ChIPS diagnoses in an outpatient clinical sample of 50 parent-child pairs aged 7-14. Agreement between most diagnoses was moderate to high between the instruments and with consensus clinical diagnoses. ChIPS was significantly briefer to administer than the K-SADS. Interviewer experience level and participant demographics did not appear to affect agreement. Results provide further evidence for the validity of the ChIPS and support its use in clinical and research settings.

A nuclear magnetic double resonance study of N-beta-bis-(beta'-chloroethyl) phosphonylethyl-DL-phenylalanine.

PubMed

Friedman, M; Boyd, W A

1977-01-01

Studies were carried out on the effect of decoupling, deuterium labeling, concentration, temperature, and solvent media on the NMR parameters of the vinyl phosphonate adduct of phenylalanine, C6H5CH2CH(COO-)NH2+CH2CH2PO(OCH2CH2C1)2. The results permit assignments of chemical shifts and coupling constants to the various protons of this molecule which contains unique structural features. The NH2+-CH2-protons are deshielded by more than 1 ppm than the CH2-PO-protons. The -OCH2-protons are nonequivalent exhibiting a fine split. Possible sources of the fine split include NH...O=P hydrogen bonding. The deuterium-labeling method should be applicable for synthesizing deuterium-and tritium-labeled crosslinked amino acids such as lysinoalanine and lanthionine and demonstrating analgous dehydroalanine-alpha-amino group-crosslinking.

Enhancing Antibody Fc Heterodimer Formation through Electrostatic Steering Effects

PubMed Central

Gunasekaran, Kannan; Pentony, Martin; Shen, Min; Garrett, Logan; Forte, Carla; Woodward, Anne; Ng, Soo Bin; Born, Teresa; Retter, Marc; Manchulenko, Kathy; Sweet, Heather; Foltz, Ian N.; Wittekind, Michael; Yan, Wei

2010-01-01

Naturally occurring IgG antibodies are bivalent and monospecific. Bispecific antibodies having binding specificities for two different antigens can be produced using recombinant technologies and are projected to have broad clinical applications. However, co-expression of multiple light and heavy chains often leads to contaminants and pose purification challenges. In this work, we have modified the CH3 domain interface of the antibody Fc region with selected mutations so that the engineered Fc proteins preferentially form heterodimers. These novel mutations create altered charge polarity across the Fc dimer interface such that coexpression of electrostatically matched Fc chains support favorable attractive interactions thereby promoting desired Fc heterodimer formation, whereas unfavorable repulsive charge interactions suppress unwanted Fc homodimer formation. This new Fc heterodimer format was used to produce bispecific single chain antibody fusions and monovalent IgGs with minimal homodimer contaminants. The strategy proposed here demonstrates the feasibility of robust production of novel Fc-based heterodimeric molecules and hence broadens the scope of bispecific molecules for therapeutic applications. PMID:20400508

Space storable propellant performance program coaxial injector characterization

NASA Technical Reports Server (NTRS)

Burick, R. J.

1972-01-01

An experimental program was conducted to characterize the circular coaxial injector concept for application with the space-storable gas/liquid propellant combination FLOX(82.6% F2)/CH4(g) at high pressure. The primary goal of the program was to obtain high characteristic velocity efficiency in conjunction with acceptable injector/chamber compatibility. A series of subscale (single element) cold flow and hot fire experiments was employed to establish design criteria for a 3000-lbf (sea level) engine operating at 500 psia. The subscale experiments characterized both high performance core elements and peripheral elements with enhanced injector/chamber compatibility. The full-scale injector which evolved from the study demonstrated a performance level of 99 percent of the theoretical shifting characteristic exhaust velocity with low chamber heat flux levels. A 44-second-duration firing demonstrated the durability of the injector. Parametric data are presented that are applicable for the design of circular, coaxial injectors that operate with injection dynamics (fuel and oxidizer velocity, etc.) similar to those employed in the work reported.

System catalytic neutralization control of combustion engines waste gases in mining technologies

NASA Astrophysics Data System (ADS)

Korshunov, G. I.; Solnitsev, R. I.

2017-10-01

The paper presents the problems solution of the atmospheric air pollution with the exhaust gases of the internal combustion engines, used in mining technologies. Such engines are used in excavators, bulldozers, dump trucks, diesel locomotives in loading and unloading processes and during transportation of minerals. NOx, CO, CH emissions as the waste gases occur during engine operation, the concentration of which must be reduced to the standard limits. The various methods and means are used for the problem solution, one of which is neutralization based on platinum catalysts. A mathematical model of a controlled catalytic neutralization system is proposed. The simulation results confirm the increase in efficiency at start-up and low engine load and the increase in the catalyst lifetime.

Internationalizing Practical ChE Education: The M.I.T. Practice School in Japan.

ERIC Educational Resources Information Center

O'Connor, Andrea J.; Kandas, Angelo W.; Natori, Yukikazu; Hatton, T. Alan

1999-01-01

Describes the establishment, benefits, and difficulties of an overseas branch of the Massachusetts Institute of Technology's (MIT) chemical engineering Practice School for student internship study at the Mitsubishi Chemical Corporation's Mizushima Plant in Kurashiki, Japan. (WRM)

Five Lectures on Nuclear Reactors Presented at Cal Tech

DOE R&D Accomplishments Database

Weinberg, Alvin M.

1956-02-10

The basic issues involved in the physics and engineering of nuclear reactors are summarized. Topics discussed include theory of reactor design, technical problems in power reactors, physical problems in nuclear power production, and future developments in nuclear power. (C.H.)

Contribution of photosynthesized carbon to the methane emitted from paddy fields

NASA Astrophysics Data System (ADS)

Minoda, T.; Kimura, M.

1994-09-01

Emission rates of CH4 from paddy soil with and without rice straw applications were measured with pot experiments to estimate the contribution of rice straw to total CH4 emissions during the growing season. The CH4 derived from rice straw was calculated to be 50.4% of the total emission. 13CO2 uptake experiments were carried out three times from Aug. 8 to Sept. 18 to estimate the contribution of photosynthesized carbon to CH4 emission. The contribution percentages of photosynthesized carbon to the total CH4 emitted to the atmosphere were 72-110% around Aug. 8, 29-36% around Aug. 30, and 13-17% around Sept. 18, 1993.

The ionic charge of Copper-64 complexes conjugated to an engineered antibody effects biodistribution

DOE PAGES

Dearling, Jason L. J.; Smith, Suzanne V.; Paterson, Brett M.; ...

2015-04-15

The development of biomolecules as imaging probes requires radiolabeling methods that do not significantly influence their biodistribution. Sarcophagine (Sar) chelators form extremely stable complexes with copper, and are therefore a promising option for labeling proteins with ⁶⁴Cu. However, initial studies using the first-generation sarcophagine bifunctional chelator SarAr to label the engineered antibody fragment ch14.18-ΔC H2 (MW 120 kDa) with ⁶⁴Cu showed high tracer retention in the kidneys,(>38% injected dose per gram (ID/g) 48 h post-injection), presumably because the high local positive charge on the Cu II-SarAr moiety resulted in increased binding of the labeled protein to the negatively charged basalmore » cells of the glomerulus. To test this hypothesis, ch14.18-ΔC H2 was conjugated with a series of Sar derivatives of decreasing positive charge and three commonly used macrocyclic polyaza polycarboxylate (PAC) BFCs. The immunoconjugates were labeled with ⁶⁴Cu and injected into mice, and PET/CT images were obtained at 24 and 48 h post injection (p.i.). At 48 h p.i., ex vivo biodistribution was carried out. In addition, to demonstrate the potential of metastasis detection using ⁶⁴Cu-labeled ch14.18-ΔC H2, a preclinical imaging study of intrahepatic neuroblastoma tumors was performed carried out. Reducing the positive charge on the Sar chelators decreased kidney uptake of Cu-labeled ch14.18-ΔC H2 by more than 6-fold, from >45 ID/g to <6% ID/g, while the uptake in most other tissues, including liver, was relatively unchanged. However, despite this dramatic decrease, the renal uptake of the PAC BFCs was generally lower than that of the Sar derivatives, as was the liver uptake. Uptake of ⁶⁴Cu-labeled ch14.18-ΔC H2 in neuroblastoma hepatic metastases was detected using PET.« less

Air Bursting Munition ABM Medium Calibre Applications

DTIC Science & Technology

2001-04-18

NDIA 45th Annual Fuze Conference - Long Beach, CA - April 16-18, 2001 Folie 1 P2 15548 BB, P-VP/FD/11, © 2001 Oerlikon Contraves AG, Zürich...Switzerland Air Bursting Munition ABM Medium Calibre Applications Allan Buckley & Pierre Freymond Oerlikon Contraves Pyrotec AG CH-8050 Zurich...Project Number Task Number Work Unit Number Performing Organization Name(s) and Address(es) Oerlikon Contraves Pyrotec AG CH-8050 Zurich / Switzerland

Ligand-accelerated non-directed C-H functionalization of arenes.

PubMed

Wang, Peng; Verma, Pritha; Xia, Guoqin; Shi, Jun; Qiao, Jennifer X; Tao, Shiwei; Cheng, Peter T W; Poss, Michael A; Farmer, Marcus E; Yeung, Kap-Sun; Yu, Jin-Quan

2017-11-22

The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.

Ligand-accelerated non-directed C-H functionalization of arenes

NASA Astrophysics Data System (ADS)

Wang, Peng; Verma, Pritha; Xia, Guoqin; Shi, Jun; Qiao, Jennifer X.; Tao, Shiwei; Cheng, Peter T. W.; Poss, Michael A.; Farmer, Marcus E.; Yeung, Kap-Sun; Yu, Jin-Quan

2017-11-01

The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.

Application of fungal chitosan incorporated with pomegranate peel extract as edible coating for microbiological, chemical and sensorial quality enhancement of Nile tilapia fillets.

PubMed

Alsaggaf, Mohammed S; Moussa, Shaaban H; Tayel, Ahmed A

2017-06-01

Fish are generous sources for providing man with his essential nutritional requirements, but the extreme susceptibility to quality deterioration hinders their optimal usage and storage. Natural derivatives are always the perfect alternatives for food preservation. The application of fungal chitosan (Ch), from Aspergillus niger, and pomegranate peel extract (PPE), in coating films for Nile tilapia (Oreochromis niloticus) fillets preservation ‎and maintaining their microbiological, chemical and sensorial quality during cooled storage at 4°C for 30days, was investigated.‎ Fish fillet were coated with Ch (2%) and combined Ch+PPE, at PPE percentages of 0.5, 1.0, 1.5 and 2.0%. Fillets coating resulted in sharp decrease of the entire microbial counts during storage; the increased concentrations from PPE strengthened coating film antimicrobial activity. Additionally, fillets coating could retard the chemical spoilage parameters increasing, i.e. nitrogen volatile base (TVB-N), peroxide value (PV) and reactive substances of thiobarbituric acid (TBARS), during storage period. The sensory evaluation indicated higher preferences for the odor, texture, color and overall quality of coated samples. Fish fillets coating with Ch and Ch+PPE could be recommended for shelf life extension and maintaining the microbiological, chemical and sensorial quality through the application of safe preservatives from natural origins. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced Condensation of R-113 on a Small Bundle of Horizontal Tubes

DTIC Science & Technology

1991-12-01

Anthony J. l lcaley, Ch an )epartment of Mechanic’ Engineering ABSTRACT Condensation of R-113 was studied using an evaporator/condenser test platform. The...IF 7825 FOR I=1 TO Npair5 7830 ENTER @File;Xa,Ya 7835 S×=Sx+Xa 7840 Sy=Sy+Ya 7845 5x2=Sx2+XaŖ 7850 Sxy-Sxy+Xa*Ya 7855 X=(Xa-Xmin)*Sfx 7860 Y-(Ya-Ymin...9th Int. Heat Transfer Conf., Vol. 3, pp. 15-20, 1990. 33. Fujii, T., Wang, W. Ch ., Koyama, Sh. and Y. Shimizu, Heat Transfer Enhancement for Gravity

Metalimnetic oxygen minima alter the vertical profiles of carbon dioxide and methane in a managed freshwater reservoir.

PubMed

McClure, Ryan P; Hamre, Kathleen D; Niederlehner, B R; Munger, Zackary W; Chen, Shengyang; Lofton, Mary E; Schreiber, Madeline E; Carey, Cayelan C

2018-04-30

Metalimnetic oxygen minimum zones (MOMs) commonly develop during the summer stratified period in freshwater reservoirs because of both natural processes and water quality management. While several previous studies have examined the causes of MOMs, much less is known about their effects, especially on reservoir biogeochemistry. MOMs create distinct redox gradients in the water column which may alter the magnitude and vertical distribution of dissolved methane (CH 4 ) and carbon dioxide (CO 2 ). The vertical distribution and diffusive efflux of CH 4 and CO 2 was monitored for two consecutive open-water seasons in a eutrophic reservoir that develops MOMs as a result of the operation of water quality engineering systems. During both summers, elevated concentrations of CH 4 accumulated within the anoxic MOM, reaching a maximum of 120 μM, and elevated concentrations of CO 2 accumulated in the oxic hypolimnion, reaching a maximum of 780 μM. Interestingly, the largest observed diffusive CH 4 effluxes occurred before fall turnover in both years, while peak diffusive CO 2 effluxes occurred both before and during turnover. Our data indicate that MOMs can substantially change the vertical distribution of CH 4 and CO 2 in the water column in reservoirs, resulting in the accumulation of CH 4 in the metalimnion (vs. at the sediments) and CO 2 in the hypolimnion. Copyright © 2018 Elsevier B.V. All rights reserved.

An Investigation of Methyl Viologen Functionalized Reduced Graphene Oxide: Chitosan as a Support for Pt Nanoparticles Towards Ethanol Electrooxidation

NASA Astrophysics Data System (ADS)

Ekrami-Kakhki, Mehri-Saddat; Farzaneh, Nahid; Abbasi, Sedigheh; Beitollahi, Hadi; Ekrami-Kakhki, Seyed Ali

2018-05-01

In this research, graphene oxide was prepared by a modified Hummers' method, and then functionalized with 1, 1'-dimethyl-4, 4'-bipyridinium dichloride (MV), and chitosan (CH) to get a MV-RGO-CH support. Pt nanoparticles were prepared on this support to get Pt/MV-RGO-CH catalyst. The morphology and microstructure of Pt/MV-RGO-CH catalyst were characterized with transmission electron microscopy image and X-ray diffraction analysis. The electrocatalytic activity of the prepared catalyst towards ethanol oxidation was investigated by carbon monoxide stripping voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. The effects of some experimental parameters such as scan rate, ethanol concentration, and temperature were investigated for ethanol electrooxidation at Pt/MV-RGO-CH catalyst. Durability of the catalyst was also investigated. The electrocatalytic performance of Pt/MV-RGO-CH catalyst for ethanol oxidation was compared with those of Pt/CH and Pt/MV-RGO catalysts. The higher electrocatalytic performance of Pt/MV-RGO-CH than Pt/CH and Pt/MV-RGO catalysts towards ethanol electrooxidation indicated that Pt/MV-RGO-CH could be a promising catalyst for application in direct ethanol fuel cells.

Anticholinesterase poisoning of birds: Field monitoring and diagnosis of acute poisoning

USGS Publications Warehouse

Hill, E.F.; Fleming, W.J.

1982-01-01

Organophosphorus and carbamate pesticides are cholinesterase (ChE) inhibiting chemicals that have been responsible for avian die-offs. Identification of chemicals implicated in these die-offs is difficult and sometimes conclusions are solely circumstantial. However, when marked depression (inhibition) of brain ChE activity accompanies organophosphorus or carbamate residues in body tissues or ingesta, cause-effect diagnosis is enhanced. To achieve this end, normal brain ChE activity is estimated for controls of the affected species and then die-off specimens are individually evaluated for evidence of ChE inhibition. This approach to evaluation of antiChE poisoning may also be used to monitor exposure of vertebrates to field application of organophosphorus or carbamate pesticides. Problems associated with this kind of evaluation, and the main topic of this report, include variability of brain ChE activity among species, postmortem influences of ambient conditions (storage or field) on ChE activity, and differential patterns of ChE activity when inhibited by organophosphorus or carbamate compounds. Other topics discussed are the ChE assay procedure, example case reports and interpretation, and research needed for improving the diagnostic utility of ChE activity in a field situation.

Metamaterial Absorbers for Infrared Detection of Molecular Self-Assembled Monolayers

PubMed Central

Ishikawa, Atsushi; Tanaka, Takuo

2015-01-01

The emerging field of plasmonic metamaterials has introduced new degree of freedom to manipulate optical field from nano to macroscopic scale, offering an attractive platform for sensing applications. So far, metamaterial sensor concepts, however, have focused on hot-spot engineering to improve the near-field enhancement, rather than fully exploiting tailored material properties. Here, we present a novel spectroscopic technique based on the metamaterial infrared (IR) absorber allowing for a low-background detection scheme as well as significant plasmonic enhancement. Specifically, we experimentally demonstrate the resonant coupling of plasmonic modes of a metamaterial absorber and IR vibrational modes of a molecular self-assembled monolayer. The metamaterial consisting of an array of Au/MgF2/Au structures exhibits an anomalous absorption at ~3000 cm−1, which spectrally overlaps with C-H stretching vibrational modes. Symmetric/asymmetric C-H stretching modes of a 16-Mercaptohexadecanoic acid monolayer are clearly observed as Fano-like anti-resonance peaks within a broad plasmonic absorption of the metamaterial. Spectral analysis using Fano line-shape fitting reveals the underlying resonant interference in plasmon-molecular coupled systems. Our metamaterial approach achieves the attomole sensitivity with a large signal-to-noise ratio in the far-field measurement, thus may open up new avenues for realizing ultrasensitive IR inspection technologies. PMID:26229011

The Tracer Gas Method of Determining the Charging Efficiency of Two-stroke-cycle Diesel Engines

NASA Technical Reports Server (NTRS)

Schweitzer, P H; Deluca, Frank, Jr

1942-01-01

A convenient method has been developed for determining the scavenging efficiency or the charging efficiency of two-stroke-cycle engines. The method consists of introducing a suitable tracer gas into the inlet air of the running engine and measuring chemically its concentration both in the inlet and exhaust gas. Monomethylamine CH(sub 3)NH(sub 2) was found suitable for the purpose as it burns almost completely during combustion, whereas the "short-circuited" portion does not burn at all and can be determined quantitatively in the exhaust. The method was tested both on four-stroke and on two-stroke engines and is considered accurate within 1 percent.

libChEBI: an API for accessing the ChEBI database.

PubMed

Swainston, Neil; Hastings, Janna; Dekker, Adriano; Muthukrishnan, Venkatesh; May, John; Steinbeck, Christoph; Mendes, Pedro

2016-01-01

ChEBI is a database and ontology of chemical entities of biological interest. It is widely used as a source of identifiers to facilitate unambiguous reference to chemical entities within biological models, databases, ontologies and literature. ChEBI contains a wealth of chemical data, covering over 46,500 distinct chemical entities, and related data such as chemical formula, charge, molecular mass, structure, synonyms and links to external databases. Furthermore, ChEBI is an ontology, and thus provides meaningful links between chemical entities. Unlike many other resources, ChEBI is fully human-curated, providing a reliable, non-redundant collection of chemical entities and related data. While ChEBI is supported by a web service for programmatic access and a number of download files, it does not have an API library to facilitate the use of ChEBI and its data in cheminformatics software. To provide this missing functionality, libChEBI, a comprehensive API library for accessing ChEBI data, is introduced. libChEBI is available in Java, Python and MATLAB versions from http://github.com/libChEBI, and provides full programmatic access to all data held within the ChEBI database through a simple and documented API. libChEBI is reliant upon the (automated) download and regular update of flat files that are held locally. As such, libChEBI can be embedded in both on- and off-line software applications. libChEBI allows better support of ChEBI and its data in the development of new cheminformatics software. Covering three key programming languages, it allows for the entirety of the ChEBI database to be accessed easily and quickly through a simple API. All code is open access and freely available.

Evaluation of Biodiesel Fuels to Reduce Fossil Fuel Use in Corps of Engineers Floating Plant Operations

DTIC Science & Technology

2016-07-01

ER D C/ CH L TR -1 6- 11 Dredging Operations and Environmental Research Program Evaluation of Biodiesel Fuels to Reduce Fossil Fuel Use...Fuels to Reduce Fossil Fuel Use in Corps of Engineers Floating Plant Operations Michael Tubman and Timothy Welp Coastal and Hydraulics Laboratory...sensitive emissions, increase use of renewable energy, and reduce the use of fossil fuels was conducted with funding from the U.S. Army Corps of

Identifying Areas of Potential Wetland Hydrology in Irrigated Croplands Using Aerial Image Interpretation and Analysis of Rainfall Normality

DTIC Science & Technology

2016-06-01

engineering and environmental challenges. ERDC develops innovative solutions in civil and military engineering, geospatial sciences, water resources, and... tte rn o f p ea ks , i nd ic at in g th e we t p or tio n of ea ch y ea r, fo llo we d by a s ha rp d ec lin e in to th e dr y s ea so

Combustion Limits and Efficiency of Turbojet Engines

NASA Technical Reports Server (NTRS)

Barnett, H. C.; Jonash, E. R.

1956-01-01

Combustion must be maintained in the turbojet-engine combustor over a wide range of operating conditions resulting from variations in required engine thrust, flight altitude, and flight speed. Furthermore, combustion must be efficient in order to provide the maximum aircraft range. Thus, two major performance criteria of the turbojet-engine combustor are (1) operatable range, or combustion limits, and (2) combustion efficiency. Several fundamental requirements for efficient, high-speed combustion are evident from the discussions presented in chapters III to V. The fuel-air ratio and pressure in the burning zone must lie within specific limits of flammability (fig. 111-16(b)) in order to have the mixture ignite and burn satisfactorily. Increases in mixture temperature will favor the flammability characteristics (ch. III). A second requirement in maintaining a stable flame -is that low local flow velocities exist in the combustion zone (ch. VI). Finally, even with these requirements satisfied, a flame needs a certain minimum space in which to release a desired amount of heat, the necessary space increasing with a decrease in pressure (ref. 1). It is apparent, then, that combustor design and operation must provide for (1) proper control of vapor fuel-air ratios in the combustion zone at or near stoichiometric, (2) mixture pressures above the minimum flammability pressures, (3) low flow velocities in the combustion zone, and (4) adequate space for the flame.

Performance of green waste biocovers for enhancing methane oxidation.

PubMed

Mei, Changgen; Yazdani, Ramin; Han, Byunghyun; Mostafid, M Erfan; Chanton, Jeff; VanderGheynst, Jean; Imhoff, Paul

2015-05-01

Green waste aged 2 and 24months, labeled "fresh" and "aged" green waste, respectively, were placed in biocover test cells and evaluated for their ability to oxidize methane (CH4) under high landfill gas loading over a 15-month testing period. These materials are less costly to produce than green waste compost, yet satisfied recommended respiration requirements for landfill compost covers. In field tests employing a novel gas tracer to correct for leakage, both green wastes oxidized CH4 at high rates during the first few months of operation - 140 and 200g/m(2)/day for aged and fresh green waste, respectively. Biocover performance degraded during the winter and spring, with significant CH4 generated from anaerobic regions in the 60-80cm thick biocovers. Concurrently, CH4 oxidation rates decreased. Two previously developed empirical models for moisture and temperature dependency of CH4 oxidation in soils were used to test their applicability to green waste. Models accounted for 68% and 79% of the observed seasonal variations in CH4 oxidation rates for aged green waste. Neither model could describe similar seasonal changes for the less stable fresh green waste. This is the first field application and evaluation of these empirical models using media with high organic matter. Given the difficulty of preventing undesired CH4 generation, green waste may not be a viable biocover material for many climates and landfill conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Lignocellulose nanofibers prepared by ionic liquid pretreatment and subsequent mechanical nanofibrillation of bagasse powder: Application to esterified bagasse/polypropylene composites.

PubMed

Ninomiya, Kazuaki; Abe, Megumi; Tsukegi, Takayuki; Kuroda, Kosuke; Tsuge, Yota; Ogino, Chiaki; Taki, Kentaro; Taima, Tetsuya; Saito, Joji; Kimizu, Mitsugu; Uzawa, Kiyoshi; Takahashi, Kenji

2018-02-15

In the present study, we examined the efficacy of choline acetate (ChOAc, a cholinium ionic liquid))-assisted pretreatment of bagasse powder for subsequent mechanical nanofibrillation to produce lignocellulose nanofibers. Bagasse sample with ChOAc pretreatment and subsequent nanofibrillation (ChOAc/NF-bagasse) was prepared and compared to untreated control bagasse sample (control bagasse), bagasse sample with nanofibrillation only (NF-bagasse) and with ChOAc pretreatment only (ChOAc-bagasse). The specific surface area was 0.83m 2 /g, 3.1m 2 /g, 6.3m 2 /g, and 32m 2 /g for the control bagasse, ChOAc-bagasse, NF-bagasse, and the ChOAc/NF-bagasse, respectively. Esterified bagasse/polypropylene composites were prepared using the bagasse samples. ChOAc/NF-bagasse exhibited the best dispersion in the composites. The tensile toughness of the composites was 0.52J/cm 3 , 0.73J/cm 3 , 0.92J/cm 3 , and 1.29J/cm 3 for the composites prepared using control bagasse, ChOAc-bagasse, NF-bagasse, and ChOAc/NF-bagasse, respectively. Therefore, ChOAc pretreatment and subsequent nanofibrillation of bagasse powder resulted in enhanced tensile toughness of esterified bagasse/polypropylene composites. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental and Estimated Rate Constants for the Reactions of Hydroxyl Radicals with Several Halocarbons

NASA Technical Reports Server (NTRS)

DeMore, W.B.

1996-01-01

Relative rate experiments are used to measure rate constants and temperature dependencies of the reactions of OH with CH3F (41), CH2FCl (31), CH2BrCl (30B1), CH2Br2 (3OB2), CHBr3 (2OB3), CF2BrCHFCl (123aBl(alpha)), and CF2ClCHCl2 (122). Rate constants for additional compounds of these types are estimated using an empirical rate constant estimation method which is based on measured rate constants for a wide range of halocarbons. The experimental data are combined with the estimated and previously reported rate constants to illustrate the effects of F, Cl, and Br substitution on OH rate constants for a series of 19 halomethanes and 25 haloethanes. Application of the estimation technique is further illustrated for some higher hydrofluorocarbons (HFCs), including CHF2CF2CF2CF2H (338pcc), CF3CHFCHFCF2CF3 (43-10mee), CF3CH2CH2CF3 (356ffa), CF3CH2CF2CH2CF3 (458mfcf), CF3CH2CHF2 (245fa), and CF3CH2CF2CH3 (365mfc). The predictions are compared with literature data for these compounds.

Phase Engineering of Perovskite Materials for High-Efficiency Solar Cells: Rapid Conversion of CH3NH3PbI3 to Phase-Pure CH3NH3PbCl3 via Hydrochloric Acid Vapor Annealing Post-Treatment.

PubMed

Zhou, Weiran; Zhou, Pengcheng; Lei, Xunyong; Fang, Zhimin; Zhang, Mengmeng; Liu, Qing; Chen, Tao; Zeng, Hualing; Ding, Liming; Zhu, Jun; Dai, Songyuan; Yang, Shangfeng

2018-01-17

Organometal halide CH 3 NH 3 PbI 3 (MAPbI 3 ) has been commonly used as the light absorber layer of perovskite solar cells (PSCs), and, especially, another halide element chlorine (Cl) has been often incorporated to assist the crystallization of perovskite film. However, in most cases, a predominant MAPbI 3 phase with trace of Cl - is obtained ultimately and the role of Cl involvement remains unclear. Herein, we develop a low-cost and facile method, named hydrochloric acid vapor annealing (HAVA) post-treatment, and realize a rapid conversion of MAPbI 3 to phase-pure MAPbCl 3 , demonstrating a new concept of phase engineering of perovskite materials toward efficiency enhancement of PSCs for the first time. The average grain size of perovskite film after HAVA post-treatment increases remarkably through an Ostwald ripening process, leading to a denser and smoother perovskite film with reduced trap states and enhanced crystallinity. More importantly, the generation of MAPbCl 3 secondary phase via phase engineering is beneficial for improving the carrier mobility with a more balanced carrier transport rate and enlarging the band gap of perovskite film along with optimized energy level alignment. As a result, under the optimized HAVA post-treatment time (2 min), we achieved a significant enhancement of the power conversion efficiency (PCE) of the MAPbI 3 -based planar heterojunction-PSC device from 14.02 to 17.40% (the highest PCE reaches 18.45%) with greatly suppressed hysteresis of the current-voltage response.

ENGINEERED NEAR SURFACE DISPOSAL FACILITY OF THE INDUSTRIAL COMPLEX FOR SOLID RADWASTE MANAGEMENT AT CHERNOBYL NUCLEAR POWER PLANT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ziehm, Ronny; Pichurin, Sergey Grigorevich

2003-02-27

As a part of the turnkey project ''Industrial Complex for Solid Radwaste Management (ICSRM) at the Chernobyl Nuclear Power Plant (ChNPP)'' an Engineered Near Surface Disposal Facility (ENSDF, LOT 3) will be built on the VEKTOR site within the 30 km Exclusion Zone of the ChNPP. This will be performed by RWE NUKEM GmbH, Germany, and it governs the design, licensing support, fabrication, assembly, testing, inspection, delivery, erection, installation and commissioning of the ENSDF. The ENSDF will receive low to intermediate level, short lived, processed/conditioned wastes from the ICSRM Solid Waste Processing Facility (SWPF, LOT 2), the ChNPP Liquid Radwastemore » Treatment Plant (LRTP) and the ChNPP Interim Storage Facility for RBMK Fuel Assemblies (ISF). The ENSDF has a capacity of 55,000 m{sup 3}. The primary functions of the ENSDF are: to receive, monitor and record waste packages, to load the waste packages into concrete disposal units, to enable capping and closure of the disposal unit s, to allow monitoring following closure. The ENSDF comprises the turnkey installation of a near surface repository in the form of an engineered facility for the final disposal of LILW-SL conditioned in the ICSRM SWPF and other sources of Chernobyl waste. The project has to deal with the challenges of the Chernobyl environment, the fulfillment of both Western and Ukrainian standards, and the installation and coordination of an international project team. It will be shown that proven technologies and processes can be assembled into a unique Management Concept dealing with all the necessary demands and requirements of a turnkey project. The paper emphasizes the proposed concepts for the ENSDF and their integration into existing infrastructure and installations of the VEKTOR site. Further, the paper will consider the integration of Western and Ukrainian Organizations into a cohesive project team and the requirement to guarantee the fulfillment of both Western standards and Ukrainian regulations and licensing requirements. The paper provides information on the output of the Detail Design and will reflect the progress of the design work.« less

Propulsion Technology Needs for Exploration

NASA Technical Reports Server (NTRS)

Brown, Thomas

2007-01-01

The objectives of currently planned exploration efforts, as well as those further in the future, require significant advancements in propulsion technologies. The current Lunar exploration architecture has set goals and mission objectives that necessitate the use of new systems and the extension of existing technologies beyond present applications. In the near term, the majority of these technologies are the result of a need to apply high performing cryogenic propulsion systems to long duration in-space applications. Advancement of cryogenic propulsion to these applications is crucial to provide higher performing propulsion systems that reduce the vehicle masses; enhance the safety of vehicle systems and ground operations; and provide a path for In-situ Resource Utilization (ISRU).Use of a LOX/LH2 main propulsion system for Lunar Lander Descent is a top priority because more conventional storable propellants are far from meeting the performance needs of the current architecture. While LOX/LH2 pump feed engines have been used in flight applications for many years, these engines have limited throttle capabilities. Engines that are capable of much greater throttling while still meeting high performance goals are a necessity to achieving exploration goals. Applications of LOX/CH4 propulsion to Lander ascent propulsion systems and reaction control systems are also if interest because of desirable performance and operations improvements over conventional storable systems while being more suitable for use of in-situ produced propellants. Within the current lunar architecture, use of cryogenic propulsion for the Earth Departure Stage and Lunar Lander elements also necessitate the need for advanced Cryogenic Fluid Management technologies. These technologies include long duration propellant storage/distribution, low-gravity propellant management, cryogenic couplings and disconnects, light weight composite tanks and support structure, and subsystem integration. In addition to the propulsive and fluid management system technologies described, many component level technologies are also required to enable to the success if the integrated systems. The components include, but are not limited to, variable/throttling valves, variable position actuators, leak detectors, light weight cryogenic fluid pumps, sensor technology and others. NASA, partnering with the Aerospace Industry must endeavor to develop these, and other promising propulsion technologies, to enable the implements of the country's goals in exploration of the Moon, Mars and beyond.

Gradient nano-engineered in situ forming composite hydrogel for osteochondral regeneration.

PubMed

Radhakrishnan, Janani; Manigandan, Amrutha; Chinnaswamy, Prabu; Subramanian, Anuradha; Sethuraman, Swaminathan

2018-04-01

Fabrication of anisotropic osteochondral-mimetic scaffold with mineralized subchondral zone and gradient interface remains challenging. We have developed an injectable semi-interpenetrating network hydrogel construct with chondroitin sulfate nanoparticles (ChS-NPs) and nanohydroxyapatite (nHA) (∼30-90 nm) in chondral and subchondral hydrogel zones respectively. Mineralized subchondral hydrogel exhibited significantly higher osteoblast proliferation and alkaline phosphatase activity (p < 0.05). Osteochondral hydrogel exhibited interconnected porous structure and spatial variation with gradient interface of nHA and ChS-NPs. Microcomputed tomography (μCT) demonstrated nHA gradation while rheology showed predominant elastic modulus (∼930 Pa) at the interface. Co-culture of osteoblasts and chondrocytes in gradient hydrogels showed layer-specific retention of cells and cell-cell interaction at the interface. In vivo osteochondral regeneration by biphasic (nHA or ChS) and gradient (nHA + ChS) hydrogels was compared with control using rabbit osteochondral defect after 3 and 8 weeks. Complete closure of defect was observed in gradient (8 weeks) while defect remained in other groups. Histology demonstrated collagen and glycosaminoglycan deposition in neo-matrix and presence of hyaline cartilage-characteristic matrix, chondrocytes and osteoblasts. μCT showed mineralized neo-tissue formation, which was confined within the defect with higher bone mineral density in gradient (chondral: 0.42 ± 0.07 g/cc, osteal: 0.64 ± 0.08 g/cc) group. Further, biomechanical push-out studies showed significantly higher load for gradient group (378 ± 56 N) compared to others. Thus, the developed nano-engineered gradient hydrogel enhanced hyaline cartilage regeneration with subchondral bone formation and lateral host-tissue integration. Copyright © 2018 Elsevier Ltd. All rights reserved.

Engineered and subsequent intrinsic in situ bioremediation of a diesel fuel contaminated aquifer

NASA Astrophysics Data System (ADS)

Hunkeler, Daniel; Höhener, Patrick; Zeyer, Josef

2002-12-01

A diesel fuel contaminated aquifer in Menziken, Switzerland was treated for 4.5 years by injecting aerated groundwater, supplemented with KNO 3 and NH 4H 2PO 4 to stimulate indigenous populations of petroleum hydrocarbon (PHC) degrading microorganisms. After dissolved PHC concentrations had stabilized at a low level, engineered in situ bioremediation was terminated. The main objective of this study was to evaluate the efficacy of intrinsic in situ bioremediation as a follow-up measure to remove PHC remaining in the aquifer after terminating engineered in situ bioremediation. In the first 7 months of intrinsic in situ bioremediation, redox conditions in the source area became more reducing as indicated by lower concentrations of SO 42- and higher concentrations of Fe(II) and CH 4. In the core of the source area, strongly reducing conditions prevailed during the remaining study period (3 years) and dissolved PHC concentrations were higher than during engineered in situ bioremediation. This suggests that biodegradation in the core zone was limited by the availability of oxidants. In lateral zones of the source area, however, gradually more oxidized conditions were reestablished again, suggesting that PHC availability increasingly limited biodegradation. The total DIC production rate in the aquifer decreased within 2 years to about 25% of that during engineered in situ bioremediation and remained at that level. Stable carbon isotope analysis confirmed that the produced DIC mainly originated from PHC mineralization. The total rate of DIC and CH 4 production in the source area was more than 300 times larger than the rate of PHC elution. This indicates that biodegradation coupled to consumption of naturally occurring oxidants was an important process for removal of PHC which remained in the aquifer after terminating engineered measures.

A MAD-Bayes Algorithm for State-Space Inference and Clustering with Application to Querying Large Collections of ChIP-Seq Data Sets.

PubMed

Zuo, Chandler; Chen, Kailei; Keleş, Sündüz

2017-06-01

Current analytic approaches for querying large collections of chromatin immunoprecipitation followed by sequencing (ChIP-seq) data from multiple cell types rely on individual analysis of each data set (i.e., peak calling) independently. This approach discards the fact that functional elements are frequently shared among related cell types and leads to overestimation of the extent of divergence between different ChIP-seq samples. Methods geared toward multisample investigations have limited applicability in settings that aim to integrate 100s to 1000s of ChIP-seq data sets for query loci (e.g., thousands of genomic loci with a specific binding site). Recently, Zuo et al. developed a hierarchical framework for state-space matrix inference and clustering, named MBASIC, to enable joint analysis of user-specified loci across multiple ChIP-seq data sets. Although this versatile framework estimates both the underlying state-space (e.g., bound vs. unbound) and also groups loci with similar patterns together, its Expectation-Maximization-based estimation structure hinders its applicability with large number of loci and samples. We address this limitation by developing MAP-based asymptotic derivations from Bayes (MAD-Bayes) framework for MBASIC. This results in a K-means-like optimization algorithm that converges rapidly and hence enables exploring multiple initialization schemes and flexibility in tuning. Comparison with MBASIC indicates that this speed comes at a relatively insignificant loss in estimation accuracy. Although MAD-Bayes MBASIC is specifically designed for the analysis of user-specified loci, it is able to capture overall patterns of histone marks from multiple ChIP-seq data sets similar to those identified by genome-wide segmentation methods such as ChromHMM and Spectacle.

Aerobic Methane Oxidation in Alaskan Lakes Along a Latitudinal Transect

NASA Astrophysics Data System (ADS)

Martinez-Cruz, K. C.; Sepulveda-Jauregui, A.; Walter Anthony, K. M.; Anthony, P.; Thalasso, F.

2013-12-01

Karla Martinez-Cruz* **, Armando Sepulveda-Jauregui*, Katey M. Walter Anthony*, Peter Anthony*, and Frederic Thalasso**. * Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, Alaska. ** Biotechnology and Bioengineering Department, Cinvestav, Mexico city, D. F., Mexico. Methane (CH4) is the third most important greenhouse gas in the atmosphere, after carbon dioxide and water vapor. Boreal lakes play an important role in the current global warming by contributing as much as 6% of global atmospheric CH4 sources annually. On the other hand, aerobic methane oxidation (methanotrophy) in lake water is a fundamental process in global methane cycling that reduces the amount of CH4 emissions to the atmosphere. Several environmental factors affect aerobic methane oxidation in the water column both directly and indirectly, including concentration of CH4 and O2, temperature and carbon budgets of lakes. We analyzed the potential of aerobic methane oxidation (PMO) rates in incubations of water collected from 30 Alaskan lakes along a north-south transect during winter and summer 2011. Our findings showed an effect of CH4 and O2 concentrations, temperature and yedoma thawing permafrost on PMO activity in the lake water. The highest PMO rates were observed in summer by lakes situated on thawing yedoma permafrost, most of them located in the interior of Alaska. We also estimated that 60-80% of all CH4 produced in Alaskan lakes could be taken up by methanotrophs in the lake water column, showing the significant influence of aerobic methane oxidation of boreal lakes to the global CH4 budget.

N2O and CH4 emissions from N-fertilized rice paddy soil can be mitigated by wood vinegar application at an appropriate rate

NASA Astrophysics Data System (ADS)

Sun, Haijun; Feng, Yanfang; Ji, Yang; Shi, Weiming; Yang, Linzhang; Xing, Baoshan

2018-07-01

To understand the impacts of wood vinegar (WV), a by-product of biochar production, on N2O and CH4 emissions and their total global warming potential (GWPt) from N-fertilized rice paddy soil, a soil column experiment was conducted using three treatments: 240 kg urea-N ha-1 accompanied with 0, 5, and 10 t WV ha-1, respectively. Results showed that N2O and CH4 emission flux patterns were dominated by water regime of rice growth cycle, which was independent with WV application. The total N2O, CH4 emission loads and GWPt over rice season of three N received treatments were 6.41-8.85 kg ha-1, 127.7-405.0 kg ha-1, and 5.24-12.03 t CO2-e ha-1, respectively. Rice seasonal N2O and CH4 emissions were synchronously mitigated by 22.4% and 36.4%, respectively, when WV was applied at 5 t ha-1. Consequently, 5 t ha-1 WV treatment reduced 31.5% of GWPt compared with the urea treatment. In addition, 10 t ha-1 WV treatment exerted a more positive effect on suppressing N2O with 27.6% reduction. However, it increased GWPt by 57.2% because its CH4 emission load was increased by 101.8%. In conclusion, WV amendment applied at an appropriate rate (5 t ha-1) or combination with other CH4 control technologies were suggested to reduce both N2O and CH4 emissions and thereby the GWPt in N-fertilized rice paddy soil.

Industrial Complex for Solid Radwaste Management at Chernobyle Nuclear Power Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahner, S.; Fomin, V. V.

2002-02-26

In the framework of the preparation for the decommissioning of the Chernobyl Nuclear Power Plant (ChNPP) an Industrial Complex for Solid Radwaste Management (ICSRM) will be built under the EC TACIS Program in the vicinity of ChNPP. The paper will present the proposed concepts and their integration into existing buildings and installations. Further, the paper will consider the safety cases, as well as the integration of Western and Ukrainian Organizations into a cohesive project team and the requirement to guarantee the fulfillment of both Western standards and Ukrainian regulations and licensing requirements. The paper will provide information on the statusmore » of the interim design and the effects of value engineering on the output of basic design phase. The paper therefor summarizes the design results of the involved design engineers of the Design and Process Providers BNFL (LOT 1), RWE NUKEM GmbH (LOT 2 and General) and INITEC (LOT 3).« less

Infrared Spectra and Optical Constants of Elusive Amorphous Methane

NASA Technical Reports Server (NTRS)

Gerakines, Perry A.; Hudson, Reggie L.

2015-01-01

New and accurate laboratory results are reported for amorphous methane (CH4) ice near 10 K for the study of the interstellar medium (ISM) and the outer Solar System. Near- and mid-infrared (IR) data, including spectra, band strengths, absorption coefficients, and optical constants, are presented for the first time for this seldom-studied amorphous solid. The apparent IR band strength near 1300 cm(exp -1) (7.69 micrometer) for amorphous CH4 is found to be about 33% higher than the value long used by IR astronomers to convert spectral observations of interstellar CH4 into CH4 abundances. Although CH4 is most likely to be found in an amorphous phase in the ISM, a comparison of results from various laboratory groups shows that the earlier CH4 band strength at 1300 cm(exp -1) (7.69 micrometer) was derived from IR spectra of ices that were either partially or entirely crystalline CH4 Applications of the new amorphous-CH4 results are discussed, and all optical constants are made available in electronic form.

Evaluation of Toxicity and Biodegradability of Cholinium Amino Acids Ionic Liquids

PubMed Central

Hou, Xue-Dan; Liu, Qiu-Ping; Smith, Thomas J.; Li, Ning; Zong, Min-Hua

2013-01-01

Cholinium amino acid ionic liquids ([Ch][AA] ILs), which are wholly composed of renewable biomaterials, have recently been demonstrated to have very promising properties for applications in organic synthesis and biomass pretreatment. In this work, the toxicity of these ILs toward enzymes and bacteria was assessed, and the effect of the anion on these properties is discussed. The inhibitory potentials of this type of ILs to acetylcholinesterase were weaker approximately an order of magnitude than the traditional IL 1-butyl-3-methylimidazolium tetrafluoroborate. Additionally, the [Ch][AA] ILs displayed low toxicity toward the bacteria tested. Furthermore, the biodegradability of the [Ch][AA] ILs was evaluated via the closed bottle and CO2 headspace tests using wastewater microorganisms. All the ILs were classified as ‘readily biodegradable’ based on their high levels of mineralization (62-87%). The presence of extra carboxyl or amide groups on the amino acid side chain rendered the ILs significantly more susceptible to microbial breakdown. In addition, for most of the [Ch][AA] ILs, low toxicity correlated with good biodegradability. The low toxicity and high biodegradability of these novel [Ch][AA] make them promising candidates for use as environmentally friendly solvents in large-scale applications. PMID:23554985

Assessment of Pneumatic Controller Emission Measurements ...

EPA Pesticide Factsheets

Oil and Natural Gas (ONG) production facilities have the potential to emit greenhouse gases such as methane (CH4) and other hydrocarbons (HCs) to the atmosphere. ONG production sites have multiple emission sources including storage tank venting, enclosed combustion devices, engine exhaust, pneumatic controllers and uncontrolled leaks. Accounting for up to 37.8 percent of CH4 emissions, pneumatic controllers are one of the most significant sources of CH4 in ONG production field operations. Recent measurement studies used the only commercially-available high volume sampling (HVS) technology (Bacharach Hi Flow Sampler, Bacharach, Inc., New Kensington, PA) to quantify CH4 emission rates of pneumatic devices on ONG production pads and compare to inventory estimates. Other studies indicate that this HVS may malfunction, causing underestimates of emissions in certain scenarios encountered in ONG production and should not be used for some sources such as heavy emissions from condensate storage tanks. The HVS malfunction can occur on relatively large emissions, where the measured leak concentrations exceed 5%, and is ascribed to a sensor transition failure in the instrument. The HVS malfunction is believed to be exacerbated by several factors (large emission rates, amount of non-CH4 HCs in the emission stream, non-optimal HVS calibration frequency, firmware, and emission measurement coupling geometries). The degree to which HVS measurements of emissions from pneumatic co

The ChIP-Seq tools and web server: a resource for analyzing ChIP-seq and other types of genomic data.

PubMed

Ambrosini, Giovanna; Dreos, René; Kumar, Sunil; Bucher, Philipp

2016-11-18

ChIP-seq and related high-throughput chromatin profilig assays generate ever increasing volumes of highly valuable biological data. To make sense out of it, biologists need versatile, efficient and user-friendly tools for access, visualization and itegrative analysis of such data. Here we present the ChIP-Seq command line tools and web server, implementing basic algorithms for ChIP-seq data analysis starting with a read alignment file. The tools are optimized for memory-efficiency and speed thus allowing for processing of large data volumes on inexpensive hardware. The web interface provides access to a large database of public data. The ChIP-Seq tools have a modular and interoperable design in that the output from one application can serve as input to another one. Complex and innovative tasks can thus be achieved by running several tools in a cascade. The various ChIP-Seq command line tools and web services either complement or compare favorably to related bioinformatics resources in terms of computational efficiency, ease of access to public data and interoperability with other web-based tools. The ChIP-Seq server is accessible at http://ccg.vital-it.ch/chipseq/ .

Construction of a chimeric thermostable pyrophosphatase to facilitate its purification and immobilization by using the choline-binding tag.

PubMed

Moldes, Cristina; García, José L; García, Pedro

2004-08-01

The thermophilic inorganic pyrophosphatase (Pyr) from Thermus thermophilus has been produced in Escherichia coli fused to the C terminus of the choline-binding tag (ChB tag) derived from the choline-binding domain (ChBD) of pneumococcal LytA autolysin. The chimeric ChBD-Pyr protein retains its thermostable activity and can be purified in a single step by DEAE-cellulose affinity chromatography. Pyr can be further released from the ChBD by thrombin, using the specific protease recognition site incorporated in the C terminus of this tag. Remarkably, the ChB tag provides a selective and very strong thermostable noncovalent immobilization of ChBD-Pyr in the DEAE-cellulose matrix. The binding of choline or choline analogues, such as DEAE, confers a high thermal stability to this tag; therefore, the immobilized chimeric enzyme can be assayed at high temperature without protein leakage, demonstrating the usefulness of the ChB tag for noncovalent immobilization of thermophilic proteins. Moreover, ChBD-Pyr can be purified and immobilized in a single step on commercial DEAE-cellulose paper. The affinity of the ChB tag for this versatile solid support can be very helpful in developing many biotechnological applications.

ChEMBL web services: streamlining access to drug discovery data and utilities

PubMed Central

Davies, Mark; Nowotka, Michał; Papadatos, George; Dedman, Nathan; Gaulton, Anna; Atkinson, Francis; Bellis, Louisa; Overington, John P.

2015-01-01

ChEMBL is now a well-established resource in the fields of drug discovery and medicinal chemistry research. The ChEMBL database curates and stores standardized bioactivity, molecule, target and drug data extracted from multiple sources, including the primary medicinal chemistry literature. Programmatic access to ChEMBL data has been improved by a recent update to the ChEMBL web services (version 2.0.x, https://www.ebi.ac.uk/chembl/api/data/docs), which exposes significantly more data from the underlying database and introduces new functionality. To complement the data-focused services, a utility service (version 1.0.x, https://www.ebi.ac.uk/chembl/api/utils/docs), which provides RESTful access to commonly used cheminformatics methods, has also been concurrently developed. The ChEMBL web services can be used together or independently to build applications and data processing workflows relevant to drug discovery and chemical biology. PMID:25883136

First-principles studies on the equation-of-state, thermal-conductivity, and opacity of deuterium-tritium and polystyrene (CH) for inertial confinement fusion applications

DOE PAGES

Hu, Suxing; Collins, Lee A.; Goncharov, V. N.; ...

2016-05-26

Using first-principles (FP) methods, we have performed ab initio compute for the equation of state (EOS), thermal conductivity, and opacity of deuterium-tritium (DT) in a wide range of densities and temperatures for inertial confinement fusion (ICF) applications. These systematic investigations have recently been expanded to accurately compute the plasma properties of CH ablators under extreme conditions. In particular, the first-principles EOS and thermal-conductivity tables of CH are self-consistently built from such FP calculations, which are benchmarked by experimental measurements. When compared with the traditional models used for these plasma properties in hydrocodes, significant differences have been identified in the warmmore » dense plasma regime. When these FP-calculated properties of DT and CH were used in our hydrodynamic simulations of ICF implosions, we found that the target performance in terms of neutron yield and energy gain can vary by a factor of 2 to 3, relative to traditional model simulations.« less

Recovery of rare metal compounds from nickel-metal hydride battery waste and their application to CH4 dry reforming catalyst.

PubMed

Kanamori, Tomohiro; Matsuda, Motohide; Miyake, Michihiro

2009-09-30

The recovery of valuable components such as nickel from nickel-metal hydride (Ni-MH) battery waste by chemical processes and their applications to CH(4) dry reforming catalysts were investigated. Three types of compound, identified by XRD analysis as NiO, CeO(2) and LaCoO(3) phases, were successfully separated from the waste by a series of chemical processes at room temperature using aqueous solutions of HCl, NaOH and NH(3), and Ni component of approximately 70% in Ni-MH battery waste was recovered. The separated NiO, CeO(2) and LaCoO(3) showed catalytic activities for CH(4) dry reforming. In particular, the separated NiO easily reduced to Ni(0) at an initial stage, and exhibited excellent catalytic activity in terms of CH(4) conversion and stability. Furthermore, it was found that the resulting Ni from separated NiO exhibited an anomalous catalysis from the comparison with that from regent NiO.

Polycarbosilanes - An Overview

DTIC Science & Technology

1987-08-14

thermal stability is poor in the presence of oxygen. polydimethylsiloxanes and formaldehyde and oxides of carbon being obtained as oxidation products...The production of such species was optimized when the reaction was caTied out in a fluidized bed reactor. For ease of analysis , all Si-Cl bonds in...the product mixture were reduced to Si-H; this permitted the application of HPLC in the separation of * SCII!ME RR R R R R I-Si-CH -Si-CH 2?-Si-CH2 -Si

Fluorescence of the Flavin group in choline oxidase. Insights and analytical applications for the determination of choline and betaine aldehyde.

PubMed

Ortega, E; de Marcos, S; Sanz-Vicente, I; Ubide, C; Ostra, M; Vidal, M; Galbán, J

2016-01-15

Choline oxidase (ChOx) is a flavoenzyme catalysing the oxidation of choline (Ch) to betaine aldehyde (BA) and glycine betaine (GB). In this paper a fundamental study of the intrinsic fluorescence properties of ChOx due to Flavin Adenine Dinucleotide (FAD) is presented and some analytical applications are studied in detail. Firstly, an unusual alteration in the excitation spectra, in comparison with the absorption spectra, has been observed as a function of the pH. This is ascribed to a change of polarity in the excited state. Secondly, the evolution of the fluorescence spectra during the reaction seems to indicate that the reaction takes place in two consecutive, but partially overlapped, steps and each of them follows a different mechanism. Thirdly, the chemical system can be used to determine the Ch concentration in the range from 5×10(-6)M to 5×10(-5)M (univariate and multivariate calibration) in the presence of BA as interference, and the joint Ch+BA concentration in the range 5×10(-6)-5×10(-4)M (multivariate calibration) with mean errors under 10%; a semiquantitative determination of the BA concentration can be deduced by difference. Finally, Ch has been successfully determined in an infant milk sample. Copyright © 2015 Elsevier B.V. All rights reserved.

A Proposed 2025 Ground Systems, Systems Engineering Process

DTIC Science & Technology

2014-07-01

Ten sio ns Egy pt Int ern al Ten sio ns Ira n R eg ion al An ata go nis ms Yem en In sta bil ity Ter ror ist Ch all en ge s Sud an Co nfl ict Ter...brainstorm solutions. Meanwhile, engineers can observe what is working and program managers can assess the true tactical value of technolo- gies ...user needs into materiel solutions (Boehm, 2010). Due to the length of the existing process, decisions made and available technolo- gies that were

Coast of California Storm and Tidal Waves Study. Shoreline Movement Data Report. Portuguese Point to Mexican Border (1852-1982),

DTIC Science & Technology

1985-12-01

34.uld not be used for site-specific shoreline ch~n i analisi For USe in engieering or planning studies, the companion analysis report haid be consulted...compiled from aerial photoraphy talum 1982. This is a speciat poros map designed for use by the U.S. Army Corps of Engineers. Natonal Oceanic and...is a speciat purpose map deisigned for use by the U.S. Army Corps of Engineers, National Ocemc and Atmospheric Administration. andother agencies

Jackson Bar Training Structure Study

DTIC Science & Technology

2015-05-01

comparison of the one-dimensional bridge hydraulic routines from: HEC - RAS , HEC -2, and WSPRO. Davis, CA: U.S. Army Corps of Engineers, Hydrologic Engineering...ER D C/ CH L TR -1 5- 4 Jackson Bar Training Structure Study Co as ta l a nd H yd ra ul ic s La bo ra to ry Jeremy A. Sharp and...The hydrodynamic model was validated with gage data from the U.S. Geological Survey 02470050 Tombigbee River at Steamplant near Leroy, AL, gage

Molecular simulation of water removal from simple gases with zeolite NaA.

PubMed

Csányi, Eva; Ható, Zoltán; Kristóf, Tamás

2012-06-01

Water vapor removal from some simple gases using zeolite NaA was studied by molecular simulation. The equilibrium adsorption properties of H(2)O, CO, H(2), CH(4) and their mixtures in dehydrated zeolite NaA were computed by grand canonical Monte Carlo simulations. The simulations employed Lennard-Jones + Coulomb type effective pair potential models, which are suitable for the reproduction of thermodynamic properties of pure substances. Based on the comparison of the simulation results with experimental data for single-component adsorption at different temperatures and pressures, a modified interaction potential model for the zeolite is proposed. In the adsorption simulations with mixtures presented here, zeolite exhibits extremely high selectivity of water to the investigated weakly polar/non-polar gases demonstrating the excellent dehydration ability of zeolite NaA in engineering applications.

In vitro study of beneficial properties and safety of lactic acid bacteria isolated from Portuguese fermented meat products.

PubMed

Todorov, S D; Franco, B D G M; Wiid, I J

2014-09-01

Many lactic acid bacteria produce bacteriocins with a rather broad spectrum of inhibition, which could offer potential applications in food preservation. Bacteriocin production by starter cultures may bring advantage to these strains in competitive interactions with pathogenic bacteria from the food matrix. The objective of this study was to determine the safety of beneficial strains (Lactobacillus plantarum ST202Ch and ST216Ch, Enterococcus faecium ST211Ch, and Lactobacillus sakei ST22Ch, ST153Ch and ST154Ch) previously isolated from fermented meat products and characterised as bacteriocin producers. Auto-aggregation was strain-specific, and values of 28.97, 27.86 and 28.56% were recorded for L. sakei ST22Ch, ST153Ch and ST154Ch, respectively, 16.95 and 14.58% for L. plantarum ST202Ch and ST216Ch, respectively, and 12.77% for E. faecium ST211Ch. Various degrees of co-aggregation between 28.85 and 44.76% for Listeria monocytogenes 211 and 409, and between 23.60 to 34.96% for E. faecium ATCC 19443 were observed. According to the results of the diffusion method, the studied strains demonstrated susceptibility to penicillin G, ampicillin, amoxicillin, amoxicillin/clavulonic acid, imipenem, linezolid, and tetracycline. In addition, the susceptibility of the six strains to various non-antibiotic commercial drugs was examined. Production of β-galactosidase by L. sakei ST22Ch, ST153Ch and ST154Ch, L. plantarum ST202Ch and ST216Ch, and E. faecium ST211Ch was confirmed by employing sterile filter paper discs impregnated with o-nitrophenyl-β-D-galactopyranose. A statistically significant (P<0.001) inhibition of Mycobacterium tuberculosis growth by bacteriocins produced by L. plantarum ST202Ch (38.3%) and ST216Ch (48.6%), L. sakei ST153Ch (16.2%) and ST154Ch (16.1%), and E. faecium ST211Ch (21.7%) was observed. As determined by the polymerase chain reaction, the tested strains showed a low virulence gene profile.

An IR investigation of solid amorphous ethanol - Spectra, properties, and phase changes

NASA Astrophysics Data System (ADS)

Hudson, Reggie L.

2017-12-01

Mid- and far-infrared spectra of condensed ethanol (CH3CH2OH) at 10-160 K are presented, with a special focus on amorphous ethanol, the form of greatest astrochemical interest, and with special attention given to changes at 155-160 K. Infrared spectra of amorphous and crystalline forms are shown. The refractive index at 670 nm of amorphous ethanol at 16 K is reported, along with three IR band strengths and a density. A comparison is made to recent work on the isoelectronic compound ethanethiol (CH3CH2SH), and several astrochemical applications are suggested for future study.

An IR Investigation of Solid Amorphous Ethanol-Spectra, Properties, and Phase Changes

NASA Technical Reports Server (NTRS)

Hudson, Reggie L.

2017-01-01

Mid- and far-infrared spectra of condensed ethanol (CH3CH2OH) at 10-160 K are presented, with a special focus on amorphous ethanol, the form of greatest astrochemical interest, and with special attention given to changes at 155-160 K. Infrared spectra of amorphous and crystalline forms are shown. The refractive index at 670 nm of amorphous ethanol at 16 K is reported, along with three IR band strengths and a density. A comparison is made to recent work on the isoelectronic compound ethanethiol (CH3CH2SH), and several astrochemical applications are suggested for future study.

Development and Hot-fire Testing of Additively Manufactured Copper Combustion Chambers for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Gradl, Paul R.; Greene, Sandy Elam; Protz, Christopher S.; Ellis, David L.; Lerch, Bradley A.; Locci, Ivan E.

2017-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM), commonly referred to as additive manufacturing (AM). The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for GRCop-84 (a NASA Glenn Research Center-developed copper, chrome, niobium alloy) commensurate with powder-bed AM, evaluate bimetallic deposition, and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. To advance the processes further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic AM chambers. In addition to the LCUSP program, NASA has completed a series of development programs and hot-fire tests to demonstrate SLM GRCop-84 and other AM techniques. NASA's efforts include a 4K lbf thrust liquid oxygen/methane (LOX/CH4) combustion chamber and subscale thrust chambers for 1.2K lbf LOX/hydrogen (H2) applications that have been designed and fabricated with SLM GRCop-84. The same technologies for these lower thrust applications are being applied to 25-35K lbf main combustion chamber (MCC) designs. This paper describes the design, development, manufacturing and testing of these numerous combustion chambers, and the associated lessons learned throughout their design and development processes.

Using Screencasts in ChE Courses

ERIC Educational Resources Information Center

Falconer, John L.; deGrazia, Janet; Medlin, J. Will; Holmberg, Michael P.

2009-01-01

Screencasts are digital recordings of the output from a computer monitor, including narration. Their use was piloted in five chemical engineering courses and the feedback from students was overwhelmingly positive. The screencasts were produced on Tablet PCs using Camtasia Studio software and were posted to the Blackboard classroom management…

40 CFR 1037.104 - Exhaust emission standards for CO2, CH4, and N2O for heavy-duty vehicles at or below 14,000...

Code of Federal Regulations, 2012 CFR

2012-07-01

... additive deterioration factor of zero to measured CO2 emissions unless good engineering judgment indicates... eliminated from the pool. (v) Select the tested subconfiguration with the smallest absolute difference...

40 CFR 86.1777-99 - Calculations; exhaust emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED... subpart, with the following additional requirement: (1) Organic material non-methane hydrocarbon equivalent mass for ethanol vehicles: OMNMHCEmass=NMHCmass + (13.8756/32.042) × (CH3OH)mass + (13.8756/46.064...

40 CFR 86.1777-99 - Calculations; exhaust emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED... subpart, with the following additional requirement: (1) Organic material non-methane hydrocarbon equivalent mass for ethanol vehicles: OMNMHCEmass=NMHCmass + (13.8756/32.042) × (CH3OH)mass + (13.8756/46.064...

On the Application of Simple Experiments to the Teaching of ChE Thermodynamics

ERIC Educational Resources Information Center

McNeil, Kenneth M.

1978-01-01

This article describes the undergraduate ChE thermodynamics course at Drexel University and the reasons for incorporating a series of laboratory experiments into the course. Included is a list of lecture topics and a description of each of the experiments. (BB)

The Effects of Engine Speed and Mixture Temperature on the Knocking Characteristics of Several Fuels

DTIC Science & Technology

1940-07-01

only. NACA list dtd 28 Sep 1945; NASA TR Server website ‘ ,f. ; :,““’? ,. .--:- .— #..- “W!+ ‘ ‘:u:i’w W9SlFlCAT10#CAME1lEO~ . TilCH131CAL NOTES...A photograph of the engine ’”used.is shown in figure 1. The electric air heater is above the engine and the cathod.e- ray oscill”ograph used as a...indicated that increasing the con- “press,ion ratio fro@ 6 to 11 results in.’a decie~se in the ‘dbzisity correction fact-or of shout . “0.030 at 1,500

Adsorption of Dissolved Gases (CH4, CO2, H2, Noble Gases) by Water-Saturated Smectite Clay Minerals

NASA Astrophysics Data System (ADS)

Bourg, I. C.; Gadikota, G.; Dazas, B.

2016-12-01

Adsorption of dissolved gases by water-saturated clay minerals plays important roles in a range of fields. For example, gas adsorption in on clay minerals may significantly impact the formation of CH4 hydrates in fine-grained sediments, the behavior of CH4 in shale, CO2 leakage across caprocks of geologic CO2 sequestration sites, H2 leakage across engineered clay barriers of high-level radioactive waste repositories, and noble gas geochemistry reconstructions of hydrocarbon migration in the subsurface. Despite its importance, the adsorption of gases on clay minerals remains poorly understood. For example, some studies have suggested that clay surfaces promote the formation of CH4 hydrates, whereas others indicate that clay surfaces inhibit the formation of CH4 hydrates. Here, we present molecular dynamics (MD) simulations of the adsorption of a range of gases (CH4, CO2, H2, noble gases) on clay mineral surfaces. Our results indicate that the affinity of dissolved gases for clay mineral surfaces has a non-monotone dependence on the hydrated radius of the gas molecules. This non-monotone dependence arises from a combination of two effects: the polar nature of certain gas molecules (in particular, CO2) and the templating of interfacial water structure by the clay basal surface, which results in the presence of interfacial water "cages" of optimal size for intermediate-size gas molecules (such as Ne or Ar).

HTSstation: a web application and open-access libraries for high-throughput sequencing data analysis.

PubMed

David, Fabrice P A; Delafontaine, Julien; Carat, Solenne; Ross, Frederick J; Lefebvre, Gregory; Jarosz, Yohan; Sinclair, Lucas; Noordermeer, Daan; Rougemont, Jacques; Leleu, Marion

2014-01-01

The HTSstation analysis portal is a suite of simple web forms coupled to modular analysis pipelines for various applications of High-Throughput Sequencing including ChIP-seq, RNA-seq, 4C-seq and re-sequencing. HTSstation offers biologists the possibility to rapidly investigate their HTS data using an intuitive web application with heuristically pre-defined parameters. A number of open-source software components have been implemented and can be used to build, configure and run HTS analysis pipelines reactively. Besides, our programming framework empowers developers with the possibility to design their own workflows and integrate additional third-party software. The HTSstation web application is accessible at http://htsstation.epfl.ch.

HTSstation: A Web Application and Open-Access Libraries for High-Throughput Sequencing Data Analysis

PubMed Central

David, Fabrice P. A.; Delafontaine, Julien; Carat, Solenne; Ross, Frederick J.; Lefebvre, Gregory; Jarosz, Yohan; Sinclair, Lucas; Noordermeer, Daan; Rougemont, Jacques; Leleu, Marion

2014-01-01

The HTSstation analysis portal is a suite of simple web forms coupled to modular analysis pipelines for various applications of High-Throughput Sequencing including ChIP-seq, RNA-seq, 4C-seq and re-sequencing. HTSstation offers biologists the possibility to rapidly investigate their HTS data using an intuitive web application with heuristically pre-defined parameters. A number of open-source software components have been implemented and can be used to build, configure and run HTS analysis pipelines reactively. Besides, our programming framework empowers developers with the possibility to design their own workflows and integrate additional third-party software. The HTSstation web application is accessible at http://htsstation.epfl.ch. PMID:24475057

Effects of mixing system and pilot fuel quality on diesel-biogas dual fuel engine performance.

PubMed

Bedoya, Iván Darío; Arrieta, Andrés Amell; Cadavid, Francisco Javier

2009-12-01

This paper describes results obtained from CI engine performance running on dual fuel mode at fixed engine speed and four loads, varying the mixing system and pilot fuel quality, associated with fuel composition and cetane number. The experiments were carried out on a power generation diesel engine at 1500 m above sea level, with simulated biogas (60% CH(4)-40% CO(2)) as primary fuel, and diesel and palm oil biodiesel as pilot fuels. Dual fuel engine performance using a naturally aspirated mixing system and diesel as pilot fuel was compared with engine performance attained with a supercharged mixing system and biodiesel as pilot fuel. For all loads evaluated, was possible to achieve full diesel substitution using biogas and biodiesel as power sources. Using the supercharged mixing system combined with biodiesel as pilot fuel, thermal efficiency and substitution of pilot fuel were increased, whereas methane and carbon monoxide emissions were reduced.

Modeling greenhouse gas emissions from dairy farms

USDA-ARS?s Scientific Manuscript database

Dairy farms have been identified as an important source of greenhouse gas emissions. Within the farm, important emissions include enteric methane (CH4) from the animals, CH4 and nitrous oxide (N2O) from manure in housing facilities, during long-term storage and during field application, and N2O from...

Comparing cervical spine motion with different halo devices in a cadaveric cervical instability model.

PubMed

DiPaola, Christian P; Sawers, Andrew; Conrad, Bryan P; Horodyski, MaryBeth; DiPaola, Matthew J; Del Rossi, Gianluca; Rechtine, Glenn R

2009-01-15

Biomechanical evaluation of conventional and noninvasive halos in cadaveric C1-C2 and C5-C6 instability models. To compare the ability of a conventional halo and noninvasive halo (NIH) to immobilize the unstable cervical spine at the C1-C2 and C5-C6 levels. Many successful outcomes have been reported in cervical spine injury treatment with the conventional halo (CH); however, complications related to pin sites have been reported. The NIH was designed to overcome these complications. To date, no investigation has compared the biomechanical efficacy of the NIH with that of the CH in restricting three-dimensional cervical spine motion. A global instability was created at the C1-C2 level in 4 cadavers and at C5-C6 in 4 others. Relative motion was measured between the superior and inferior vertebrae during the donning process, execution of the log roll technique, and during the process of sitting up. This testing sequence was followed for all treatment conditions. During the application of the orthoses there was a significant increase in motion at C1-C2 instability and a trend toward increased motion at the C5-C6 instability with CH compared with NIH. In the log roll maneuver, the CH and NIH restrict motion to a similar degree at the C1-C2 instability level, except in frontal plane translation, where CH immobilizes the segment to a greater extent. For the C5-C6 instability the CH provides significantly better immobilization for lateral bending and axial translation. No significant differences were found between the NIH and CH for the sit-up maneuver at either of the levels. Donning of the NIH generates significantly less cervical spine motion than application of the CH. The CH provides superior immobilization for a C5-C6 instability during the log roll maneuver and a C1-C2 instability in the frontal plane during the log-roll maneuver. The CH and NIH immobilize the C1-C2 and C5-C6 instability to a similar degree during the sit-up maneuver.

Altered Baseline and Nicotine-Mediated Behavioral and Cholinergic Profiles in ChAT-Cre Mouse Lines.

PubMed

Chen, Edison; Lallai, Valeria; Sherafat, Yasmine; Grimes, Nickolas P; Pushkin, Anna N; Fowler, J P; Fowler, Christie D

2018-02-28

The recent development of transgenic rodent lines expressing cre recombinase in a cell-specific manner, along with advances in engineered viral vectors, has permitted in-depth investigations into circuit function. However, emerging evidence has begun to suggest that genetic modifications may introduce unexpected caveats. In the current studies, we sought to extensively characterize male and female mice from both the ChAT (BAC) -Cre mouse line, created with the bacterial artificial chromosome (BAC) method, and ChAT (IRES) -Cre mouse line, generated with the internal ribosome entry site (IRES) method. ChAT (BAC) -Cre transgenic and wild-type mice did not differ in general locomotor behavior, anxiety measures, drug-induced cataplexy, nicotine-mediated hypolocomotion, or operant food training. However, ChAT (BAC) -Cre transgenic mice did exhibit significant deficits in intravenous nicotine self-administration, which paralleled an increase in vesicular acetylcholine transporter and choline acetyltransferase (ChAT) hippocampal expression. For the ChAT (IRES) -Cre line, transgenic mice exhibited deficits in baseline locomotor, nicotine-mediated hypolocomotion, and operant food training compared with wild-type and hemizygous littermates. No differences among ChAT (IRES) -Cre wild-type, hemizygous, and transgenic littermates were found in anxiety measures, drug-induced cataplexy, and nicotine self-administration. Given that increased cre expression was present in the ChAT (IRES) -Cre transgenic mice, as well as a decrease in ChAT expression in the hippocampus, altered neuronal function may underlie behavioral phenotypes. In contrast, ChAT (IRES) -Cre hemizygous mice were more similar to wild-type mice in both protein expression and the majority of behavioral assessments. As such, interpretation of data derived from ChAT-Cre rodents must consider potential limitations dependent on the line and/or genotype used in research investigations. SIGNIFICANCE STATEMENT Altered baseline and/or nicotine-mediated behavioral profiles were discovered in transgenic mice from the ChAT (BAC) -Cre and ChAT (IRES) -Cre lines. Given that these cre-expressing mice have become increasingly used by the scientific community, either independently with chemicogenetic and optogenetic viral vectors or crossed with other transgenic lines, the current studies highlight important considerations for the interpretation of data from previous and future experimental investigations. Moreover, the current findings detail the behavioral effects of either increased or decreased baseline cholinergic signaling mechanisms on locomotor, anxiety, learning/memory, and intravenous nicotine self-administration behaviors. Copyright © 2018 the authors 0270-6474/18/382177-12$15.00/0.

Fuel Cells Advanced Drivetrain

DTIC Science & Technology

2010-08-09

T800 Silverado Military specific system upscale (4WD) HydroGen3 – CH2 HydroGen3 – LH2 4010 – Early Adopter Engineering Model (GEN Nadeau) Gen4...Timeline Maintenance Infrastructure Fort Belvoir, VA 2003-ongoing Full FCV and Volt Maintenance 350,700bar LH2 (Decommissioned) Volt Charging(pending

Incorporating High School Outreach into ChE Courses.

ERIC Educational Resources Information Center

Ross, Julia M.; Bayles, Taryn M.

2003-01-01

Describes an undergraduate-level introductory course in biomedical engineering introduced at the University of Maryland, Baltimore County which allows students to delve deeply into an area of interest not covered in the lecture material and provide a forum for students to hone their presentation and group interaction skills through outreach…

40 CFR 1065.660 - THC and NMHC determination.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false THC and NMHC determination. 1065.660... CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.660 THC and NMHC determination. (a) THC determination and THC/CH 4 initial contamination corrections. (1) If we require you to...

ASPEN Plus in the Chemical Engineering Curriculum: Suitable Course Content and Teaching Methodology

ERIC Educational Resources Information Center

Rockstraw, David A.

2005-01-01

An established methodology involving the sequential presentation of five skills on ASPEN Plus to undergraduate seniors majoring in ChE is presented in this document: (1) specifying unit operations; (2) manipulating physical properties; (3) accessing variables; (4) specifying nonstandard components; and (5) applying advanced features. This…

40 CFR 86.1340-94 - Exhaust sample analysis.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Section 86.1340-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... (except diesels), CH4 (natural gas-fueled engines only), CO, CO2. and NOX sample bag(s) with approximately... not require bag analysis.) (d)(8) through (h) [Reserved]. For guidance see § 86.1340-90. [59 FR 48534...

40 CFR 86.1340-94 - Exhaust sample analysis.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Section 86.1340-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... (except diesels), CH4 (natural gas-fueled engines only), CO, CO2. and NOX sample bag(s) with approximately... not require bag analysis.) (d)(8) through (h) [Reserved]. For guidance see § 86.1340-90. [59 FR 48534...

40 CFR 86.1340-94 - Exhaust sample analysis.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Section 86.1340-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... (except diesels), CH4 (natural gas-fueled engines only), CO, CO2. and NOX sample bag(s) with approximately... not require bag analysis.) (d)(8) through (h) [Reserved]. For guidance see § 86.1340-90. [59 FR 48534...

40 CFR 86.1340-94 - Exhaust sample analysis.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Section 86.1340-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... (except diesels), CH4 (natural gas-fueled engines only), CO, CO2. and NOX sample bag(s) with approximately... not require bag analysis.) (d)(8) through (h) [Reserved]. For guidance see § 86.1340-90. [59 FR 48534...

Detection methods for atoms and radicals in the gas phase

NASA Astrophysics Data System (ADS)

Hack, W.

This report lists atoms and free radicals in the gas phase which are of interest for environmental and flame chemistry and have been detected directly. The detection methods which have been used are discussed with respect to their range of application, specificity and sensitivity. In table 1, detection methods for the five atoms of group IV (C, Si, Ge, Sn, Pb) and about 60 radicals containing at least one atom of group IV are summarized (CH, Cd, Cf, CC1, CBr, Cn, Cs, CSe, CH2, CD2, Chf, Cdf, CHC1, CHBr, CF2, CC12, CBr2, CFC1, CFBr, CH3, CD3, CF3, CH2F, CH2C1, CH2Br, CHF2, CHC12, CHBr2, Hco, Fco, CH30, CD30, CH2OH, CH3S, Nco, CH4N, CH302, CF302; C2, C2N, C2H, C20, C2HO, C2H3, C2F3, C2H5, C2HsO, C2H4OH, CH3CO, CD3CO, C2H3O, C2H502, CH3COO2, C2H4N, C2H6N, C3; Si, SiF, SiF2, SiO, SiC, Si2; Ge, GeC, GeO, GeF, GeF2, GeCl2, Sn, SnF, SnO, SnF2, Pb, PbF, PbF2, PbO, PbS). In table 2 detection methods for about 25 other atoms and 60 radicals are listed: (H, D, O, O2, Oh, Od, HO2, DO2, F, Ci, Br, I, Fo, Cio, BrO, Io, FO2, C1O2, Li, Na, K, Rb, Cs, N, N3, Nh, Nd, Nf, Nci, NBr, NH2, ND2, Nhd, Nhf, NF2, NC12, N2H3, No, NO2, NO3, Hno, Dno, P, Ph, Pd, Pf, Pci, PH2, PD2, PF2, Po, As, AsO, AsS, Sb, Bi, S, S2, Sh, Sd, Sf, SF2, So, Hso, Dso, Sn, Se, Te, Se2, SeH, SeD, SeF, SeO, SeS, SeN, TeH, TeO, Bh, BH2, Bo, Bn, B02, Cd, Hg, UF5). The tables also cite some recent kinetic applications of the various methods.

Beneficial effect of compost utilization on reducing greenhouse gas emissions in a rice cultivation system through the overall management chain.

PubMed

Jeong, Seung Tak; Kim, Gil Won; Hwang, Hyun Young; Kim, Pil Joo; Kim, Sang Yoon

2018-02-01

Livestock manure application can stimulate greenhouse gas (GHG) emissions, especially methane (CH 4 ) in rice paddy. The stabilized organic matter (OM) is recommended to suppress CH 4 emission without counting the additional GHG emission during the composting process. To evaluate the effect of compost utilization on the net global warming potential (GWP) of a rice cropping system, the fluxes of GHGs from composting to land application were calculated by a life cycle assessment (LCA) method. The model framework was composed of GHG fluxes from industrial activities and biogenic GHG fluxes from the composting and rice cultivation processes. Fresh manure emitted 30MgCO 2 -eq.ha -1 , 90% and 10% of which were contributed by CH 4 and nitrous oxide (N 2 O) fluxes, respectively, during rice cultivation. Compost utilization decreased net GWP by 25% over that of the fresh manure during the whole process. The composting process increased the GWP of the industrial processes by 35%, but the 60% reduction in CH 4 emissions from the rice paddy mainly influenced the reduction of GWP during the overall process. Therefore, compost application could be a good management strategy to reduce GHG emissions from rice paddy systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of Augmented Spark Impinging Igniter System for Methane Engines

NASA Technical Reports Server (NTRS)

Marshall, William M.; Osborne, Robin J.; Greene, Sandra E.

2017-01-01

The Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) program is establishing multiple no-funds-exchanged Space Act Agreement (SAA) partnerships with U.S. private sector entities. The purpose of this program is to encourage the development of robotic lunar landers that can be integrated with U.S. commercial launch capabilities to deliver payloads to the lunar surface. As part of the efforts in Lander Technologies, NASA Marshall Space Flight Center (MSFC) is developing liquid oxygen (LOX) and liquid methane (LCH4) engine technology to share with the Lunar CATALYST partners. Liquid oxygen and liquid methane propellants are attractive owing to their relatively high specific impulse for chemical propulsion systems, modest storage requirements, and adaptability to NASA's Journey to Mars plans. Methane has also been viewed as a possible propellant choice for lunar missions, owing to the performance benefits and as a technology development stepping stone to Martian missions. However, in the development of methane propulsion, methane ignition has historically been viewed as a high risk area in the development of such an engine. A great deal of work has been conducted in the past decade devoted to risk reduction in LOX/CH4 ignition. This paper will review and summarize the history and results of LOX/CH4 ignition programs conducted at NASA. More recently, a NASA-developed Augmented Spark Impinging (ASI) igniter body, which utilizes a conventional spark exciter system, is being tested with LOX/CH4 to help support internal and commercial engine development programs, such as those in Lunar CATALYST. One challenge with spark exciter systems, especially at altitude conditions, is the ignition lead that transmits the high voltage pulse from the exciter to the spark igniter (spark plug). The ignition lead can be prone to corona discharge, reducing the energy delivered by the spark and potentially causing non-ignition events. For the current work, a commercial compact exciter system, which eliminates this high voltage cabling, was tested at altitude conditions. A modified, conventional exciter system with an improved ignition lead was also recently tested at altitude conditions. This test program demonstrated the capability of these exciter systems to operate at altitude. While more extensive testing may be required, these systems or similar ones may be used for future NASA and commercial engine programs.

Structural and functional characterization of an anti-West Nile virus monoclonal antibody and its single-chain variant produced in glycoengineered plants

PubMed Central

Lai, Huafang; He, Junyun; Hurtado, Jonathan; Stahnke, Jake; Fuchs, Anja; Mehlhop, Erin; Gorlatov, Sergey; Loos, Andreas; Diamond, Michael S.; Chen, Qiang

2014-01-01

Previously, our group engineered a plant-derived monoclonal antibody (MAb pE16) that efficiently treated West Nile virus (WNV) infection in mice. In this study, we developed a pE16 variant consisting of a single-chain variable fragment (scFv) fused to the heavy chain constant domains (CH) of human IgG (pE16scFv-CH). pE16 and pE16scFv-CH were expressed and assembled efficiently in Nicotiana benthamiana ΔXF plants, a glycosylation mutant lacking plant specific N-glycan residues. Glycan analysis revealed that ΔXF plant-derived pE16scFv-CH (ΔXFpE16scFv-CH) and pE16 (ΔXFpE16) both displayed a mammalian glycosylation profile. ΔXFpE16 and ΔXFpE16scFv-CH demonstrated equivalent antigen binding affinity and kinetics, and slightly enhanced neutralization of WNV in vitro compared to the parent mammalian cell-produced E16 (mE16). A single dose of ΔXFpE16 or ΔXFpE16scFv-CH protected mice against WNV-induced mortality even 4 days after infection at equivalent rates as mE16. This study provides a detailed tandem comparison of the expression, structure and function of a therapeutic MAb and its single-chain variant produced in glycoengineered plants. Moreover, it demonstrates the development of anti-WNV MAb therapeutic variants that are equivalent in efficacy to pE16, simpler to produce, and likely safer to use as therapeutics due to their mammalian N-glycosylation. This platform may lead to a more robust and cost effective production of antibody-based therapeutics against WNV infection and other infectious, inflammatory, or neoplastic diseases. PMID:24975464

Chromatin Immunoprecipitation (ChIP) Protocol for Low-abundance Embryonic Samples.

PubMed

Rehimi, Rizwan; Bartusel, Michaela; Solinas, Francesca; Altmüller, Janine; Rada-Iglesias, Alvaro

2017-08-29

Chromatin immunoprecipitation (ChIP) is a widely-used technique for mapping the localization of post-translationally modified histones, histone variants, transcription factors, or chromatin-modifying enzymes at a given locus or on a genome-wide scale. The combination of ChIP assays with next-generation sequencing (i.e., ChIP-Seq) is a powerful approach to globally uncover gene regulatory networks and to improve the functional annotation of genomes, especially of non-coding regulatory sequences. ChIP protocols normally require large amounts of cellular material, thus precluding the applicability of this method to investigating rare cell types or small tissue biopsies. In order to make the ChIP assay compatible with the amount of biological material that can typically be obtained in vivo during early vertebrate embryogenesis, we describe here a simplified ChIP protocol in which the number of steps required to complete the assay were reduced to minimize sample loss. This ChIP protocol has been successfully used to investigate different histone modifications in various embryonic chicken and adult mouse tissues using low to medium cell numbers (5 x 10 4 - 5 x 10 5 cells). Importantly, this protocol is compatible with ChIP-seq technology using standard library preparation methods, thus providing global epigenomic maps in highly relevant embryonic tissues.

Experimental Determination of Lead Interactions with Citrate and EDTA in NaCl and MgCl2 Solutions to High Ionic Strength and Its Applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiong, Yongliang; Kirkes, Leslie Dawn; Westfall, Terry

For this study, the interactions of lead with citrate and ethylenediaminetetraacetate (EDTA) are investigated based on solubility measurements as a function of ionic strength at room temperature (22.5 ± 0.5°C) in NaCl and M gCl 2 solutions. The formation constants (log β 1 0 ) for Pb[C 3H 5O(COO) 3]– (abbreviated as PbCitrate –) and Pb[(CH 2COO) 2N(CH2) 2N(CH 2COO) 2)] 2– (abbreviated as PbEDTA 2–) Pb 2+ + [C 3H 5O(COO) 3] 3– = Pb[C 3H 5O(COO) 3] – (1) Pb 2+ + (CH 2COO) 2N(CH 2) 2N(CH 2COO) 2) 4- = Pb[(CH 2COO) 2N(CH 2) 2N(CH 2COO) 2)]more » 2– (2) are evaluated as 7.28 ± 0.18 (2σ) and 20.00 ± 0.20 (2σ), respectively, with a set of Pitzer parameters describing the specific interactions in NaCl and M gCl 2 media. Based on these parameters, the interactions of lead with citrate and EDTA in various low temperature environments can be accurately modelled.« less

Selective sp3 C-H alkylation via polarity-match-based cross-coupling.

PubMed

Le, Chip; Liang, Yufan; Evans, Ryan W; Li, Ximing; MacMillan, David W C

2017-07-06

The functionalization of carbon-hydrogen (C-H) bonds is one of the most attractive strategies for molecular construction in organic chemistry. The hydrogen atom is considered to be an ideal coupling handle, owing to its relative abundance in organic molecules and its availability for functionalization at almost any stage in a synthetic sequence. Although many C-H functionalization reactions involve C(sp 3 )-C(sp 2 ) coupling, there is a growing demand for C-H alkylation reactions, wherein sp 3 C-H bonds are replaced with sp 3 C-alkyl groups. Here we describe a polarity-match-based selective sp 3 C-H alkylation via the combination of photoredox, nickel and hydrogen-atom transfer catalysis. This methodology simultaneously uses three catalytic cycles to achieve hydridic C-H bond abstraction (enabled by polarity matching), alkyl halide oxidative addition, and reductive elimination to enable alkyl-alkyl fragment coupling. The sp 3 C-H alkylation is highly selective for the α-C-H of amines, ethers and sulphides, which are commonly found in pharmaceutically relevant architectures. This cross-coupling protocol should enable broad synthetic applications in de novo synthesis and late-stage functionalization chemistry.

Selective sp3 C-H alkylation via polarity-match-based cross-coupling

NASA Astrophysics Data System (ADS)

Le, Chip; Liang, Yufan; Evans, Ryan W.; Li, Ximing; MacMillan, David W. C.

2017-07-01

The functionalization of carbon-hydrogen (C-H) bonds is one of the most attractive strategies for molecular construction in organic chemistry. The hydrogen atom is considered to be an ideal coupling handle, owing to its relative abundance in organic molecules and its availability for functionalization at almost any stage in a synthetic sequence. Although many C-H functionalization reactions involve C(sp3)-C(sp2) coupling, there is a growing demand for C-H alkylation reactions, wherein sp3 C-H bonds are replaced with sp3 C-alkyl groups. Here we describe a polarity-match-based selective sp3 C-H alkylation via the combination of photoredox, nickel and hydrogen-atom transfer catalysis. This methodology simultaneously uses three catalytic cycles to achieve hydridic C-H bond abstraction (enabled by polarity matching), alkyl halide oxidative addition, and reductive elimination to enable alkyl-alkyl fragment coupling. The sp3 C-H alkylation is highly selective for the α-C-H of amines, ethers and sulphides, which are commonly found in pharmaceutically relevant architectures. This cross-coupling protocol should enable broad synthetic applications in de novo synthesis and late-stage functionalization chemistry.

Le Châtelier reciprocal relations and the mechanical analog

NASA Astrophysics Data System (ADS)

Gilmore, Robert

1983-08-01

Le Châtelier's principle is discussed carefully in terms of two sets of simple thermodynamic examples. The principle is then formulated quantitatively for general thermodynamic systems. The formulation is in terms of a perturbation-response matrix, the Le Châtelier matrix [L]. Le Châtelier's principle is contained in the diagonal elements of this matrix, all of which exceed one. These matrix elements describe the response of a system to a perturbation of either its extensive or intensive variables. These response ratios are inverses of each other. The Le Châtelier matrix is symmetric, so that a new set of thermodynamic reciprocal relations is derived. This quantitative formulation is illustrated by a single simple example which includes the original examples and shows the reciprocities among them. The assumptions underlying this new quantitative formulation of Le Châtelier's principle are general and applicable to a wide variety of nonthermodynamic systems. Le Châtelier's principle is formulated quantitatively for mechanical systems in static equilibrium, and mechanical examples of this formulation are given.

Validation of a Brief Structured Interview: The Children’s Interview for Psychiatric Syndromes (ChIPS)

PubMed Central

Young, Matthew E.; Bell, Ziv E.; Fristad, Mary A.

2016-01-01

Evidence-based assessment is important in the treatment of childhood psychopathology (Jensen-Doss, 2011). While researchers and clinicians frequently use structured diagnostic interviews to ensure reliability, the most commonly used instrument, the Schedule for Affective Disorders and Schizophrenia for School Aged Children (K-SADS; Kaufman et al., 1997), is too long for most clinical applications. The Children’s Interview for Psychiatric Syndromes, (ChIPS/P-ChIPS; Weller, Weller, Rooney, & Fristad, 1999a; 1999b) is a highly-structured brief diagnostic interview. The present study compared K-SADS and ChIPS/P-ChIPS diagnoses in an outpatient clinical sample of 50 parent-child pairs aged 7–14. Agreement between most diagnoses was moderate to high between instruments and with consensus clinical diagnoses. ChIPS was significantly briefer to administer than the K-SADS. Interviewer experience level and participant demographics did not appear to affect agreement. Results provide further evidence for the validity of the ChIPS and support its use in clinical and research settings. PMID:27761777

Reusable and Mediator-Free Cholesterol Biosensor Based on Cholesterol Oxidase Immobilized onto TGA-SAM Modified Smart Bio-Chips

PubMed Central

Rahman, Mohammed M.

2014-01-01

A reusable and mediator-free cholesterol biosensor based on cholesterol oxidase (ChOx) was fabricated based on self-assembled monolayer (SAM) of thioglycolic acid (TGA) (covalent enzyme immobilization by dropping method) using bio-chips. Cholesterol was detected with modified bio-chip (Gold/Thioglycolic-acid/Cholesterol-oxidase i.e., Au/TGA/ChOx) by reliable cyclic voltammetric (CV) technique at room conditions. The Au/TGA/ChOx modified bio-chip sensor demonstrates good linearity (1.0 nM to 1.0 mM; R = 0.9935), low-detection limit (∼0.42 nM, SNR∼3), and higher sensitivity (∼74.3 µAµM−1cm−2), lowest-small sample volume (50.0 μL), good stability, and reproducibility. To the best of our knowledge, this is the first statement with a very high sensitivity, low-detection limit, and low-sample volumes are required for cholesterol biosensor using Au/TGA/ChOx-chips assembly. The result of this facile approach was investigated for the biomedical applications for real samples at room conditions with significant assembly (Au/TGA/ChOx) towards the development of selected cholesterol biosensors, which can offer analytical access to a large group of enzymes for wide range of biomedical applications in health-care fields. PMID:24949733

The first evidence of cholinesterases in skin mucus of carps and its applicability as biomarker of organophosphate exposure.

PubMed

Nigam, Ashwini Kumar; Srivastava, Nidhi; Rai, Amita Kumari; Kumari, Usha; Mittal, Ajay Kumar; Mittal, Swati

2014-05-01

The presence of cholinesterase (ChE) activity in skin mucus of three carps, Cirrhinus mrigala, Labeo rohita, and Catla catla and its applicability as biomarker of the organophosphorus insecticide exposure were investigated. Biochemical characterization, using specific substrates and inhibitors, indicated that measured esterase activity in skin mucus was mainly owing to ChEs. Significant difference in the proportion of acetylcholinesterase and butyrylcholinesterase activities was observed in skin mucus of three carps. Enzyme kinetic analysis, using the substrate acetylthiocholine iodide revealed significantly high Vmax value in C. catla compared to that in L. rohita and C. mrigala. In contrast, Vmax value using the substrate butyrylthiocholine iodide was significantly high in C. mrigala than in L. rohita and C. catla. In vitro treatment of skin mucus of three carps, with the organophosphorus insecticide Nuvan®, showed strong inhibition of ChE activities. In vivo experiments conducted using C. mrigala and exposing the fish to the sublethal test concentrations (5 and 15 mg/L) of the insecticide also revealed significant inhibition of ChE activity in mucus. In C. mrigala, exposed to the sublethal test concentrations of the insecticide for 4 days and then kept for recovery for 16 days, mucus ChE activity recovered to the control level. Thus, ChE activity in skin mucus could be considered a good biomarker of the organophosphorus insecticide exposure to fish and a useful tool in monitoring environmental toxicity. Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

Control of oleylamine to perovskite ratio in synthesis of MAPbBr3 nanoparticles

NASA Astrophysics Data System (ADS)

Huang, Jing; Wu, Yi-Hua; Zhu, Zhi-Gang; Shih, Wan Y.; Shih, Wei-Heng

2018-06-01

Methylammonium lead bromide (CH3NH3PbBr3) nanocrystals have great potentials for lighting and display applications. Previously we synthesized CH3NH3PbBr3 nanocrystals using oleylamine as capping molecule and found that by increasing the oleylamine to CH3NH3PbBr3 perovskite ratio (OPR), the photoluminescence wavelengths and morphology of CH3NH3PbBr3 nanocrystals could be varied from 530 nm (green) platelets to 460 nm (blue) particles. Here we modified the synthesis to direct injection of precursors into toluene and found that increasing OPR not only changes the wavelength and morphology of nanocrystals but also the size of the unit cells.

Crystal structure, stability, and optoelectronic properties of the organic-inorganic wide-band-gap perovskite CH3NH3BaI3 : Candidate for transparent conductor applications

NASA Astrophysics Data System (ADS)

Kumar, Akash; Balasubramaniam, K. R.; Kangsabanik, Jiban; Vikram, Alam, Aftab

2016-11-01

Structural stability, electronic structure, and optical properties of CH3NH3BaI3 hybrid perovskite are examined from theory as well as experiment. Solution-processed thin films of CH3NH3BaI3 exhibited a high transparency in the wavelength range of 400-825 nm (1.5-3.1 eV for which the photon current density is highest in the solar spectrum) which essentially justifies a high band gap of 4 eV obtained by theoretical estimation. Also, the x-ray diffraction patterns of the thin films match well with the {00 l } peaks of the simulated pattern obtained from the relaxed unit cell of CH3NH3BaI3 , crystallizing in the I 4 /m c m space group, with lattice parameters, a =9.30 Å, c =13.94 Å. Atom projected density of state and band structure calculations reveal the conduction and valence band edges to be comprised primarily of barium d orbitals and iodine p orbitals, respectively. The larger band gap of CH3NH3BaI3 compared to CH3NH3PbI3 can be attributed to the lower electronegativity coupled with the lack of d orbitals in the valence band of Ba2 +. A more detailed analysis reveals the excellent chemical and mechanical stability of CH3NH3BaI3 against humidity, unlike its lead halide counterpart, which degrades under such conditions. We propose La to be a suitable dopant to make this compound a promising candidate for transparent conductor applications, especially for all perovskite solar cells. This claim is supported by our calculated results on charge concentration, effective mass, and vacancy formation energies.

Seasonal variation of methane flux from coastal saline rice field with the application of different organic manures

NASA Astrophysics Data System (ADS)

Datta, A.; Yeluripati, Jagadeesh B.; Nayak, D. R.; Mahata, K. R.; Santra, S. C.; Adhya, T. K.

2013-02-01

A field experiment was conducted in an irrigated saline rice field of Gadakujang (a fishing hamlet of coastal Odisha, India, ravaged by the super cyclone of 1999 and cyclone BOB02 of 2006), to study the effects of locally available organic and fresh green manure amendment to the saline soil on methane (CH4) emission during wet and dry seasons using the conventional closed chamber flux measurement method. In a first report of this kind, CH4 emission vis-à-vis yield improvement of rice with different locally available organic manure application from coastal saline rice field soil of Odisha, is reported. The study confirms that CH4 flux from the saline soil planted to rice is significantly lower than that of irrigated inland non-saline rice field during both wet and dry seasons. Cumulative seasonal CH4 flux from different treatments of the coastal saline rice field ranged between 119.51 and 263.60 kg ha-1 during the wet season and 15.35-100.88 kg ha-1 during the dry season. Lower CH4 emission during the dry season may be attributed to the increased soil salinity (EC1:2) that went up from 0.76 dS m-1 during the wet season to 3.96 dS m-1 during the dry season. Annual CH4 emission per Mg grain yield was significantly low from plots treated with locally available green manure Morning glory (Ipomoea lacunosa) (17.27) with significantly high rice grain yield. Study indicates that Morning glory may be used as a potential green manure to increase grain yield and reduced CH4 emission from the coastal saline rice ecosystems of the tropics.

[CH(3)(CH(2))(11)NH(3)]SnI(3): a hybrid semiconductor with MoO(3)-type tin(II) iodide layers.

PubMed

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.

ChEMBL web services: streamlining access to drug discovery data and utilities.

PubMed

Davies, Mark; Nowotka, Michał; Papadatos, George; Dedman, Nathan; Gaulton, Anna; Atkinson, Francis; Bellis, Louisa; Overington, John P

2015-07-01

ChEMBL is now a well-established resource in the fields of drug discovery and medicinal chemistry research. The ChEMBL database curates and stores standardized bioactivity, molecule, target and drug data extracted from multiple sources, including the primary medicinal chemistry literature. Programmatic access to ChEMBL data has been improved by a recent update to the ChEMBL web services (version 2.0.x, https://www.ebi.ac.uk/chembl/api/data/docs), which exposes significantly more data from the underlying database and introduces new functionality. To complement the data-focused services, a utility service (version 1.0.x, https://www.ebi.ac.uk/chembl/api/utils/docs), which provides RESTful access to commonly used cheminformatics methods, has also been concurrently developed. The ChEMBL web services can be used together or independently to build applications and data processing workflows relevant to drug discovery and chemical biology. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Isolation of Cu Atoms in Pd Lattice: Forming Highly Selective Sites for Photocatalytic Conversion of CO2 to CH4.

PubMed

Long, Ran; Li, Yu; Liu, Yan; Chen, Shuangming; Zheng, Xusheng; Gao, Chao; He, Chaohua; Chen, Nanshan; Qi, Zeming; Song, Li; Jiang, Jun; Zhu, Junfa; Xiong, Yujie

2017-03-29

Photocatalytic conversion of CO 2 to CH 4 , a carbon-neutral fuel, represents an appealing approach to remedy the current energy and environmental crisis; however, it suffers from the large production of CO and H 2 by side reactions. The design of catalytic sites for CO 2 adsorption and activation holds the key to address this grand challenge. In this Article, we develop highly selective sites for photocatalytic conversion of CO 2 to CH 4 by isolating Cu atoms in Pd lattice. According to our synchrotron-radiation characterizations and theoretical simulations, the isolation of Cu atoms in Pd lattice can play dual roles in the enhancement of CO 2 -to-CH 4 conversion: (1) providing the paired Cu-Pd sites for the enhanced CO 2 adsorption and the suppressed H 2 evolution; and (2) elevating the d-band center of Cu sites for the improved CO 2 activation. As a result, the Pd 7 Cu 1 -TiO 2 photocatalyst achieves the high selectivity of 96% for CH 4 production with a rate of 19.6 μmol g cat -1 h -1 . This work provides fresh insights into the catalytic site design for selective photocatalytic CO 2 conversion, and highlights the importance of catalyst lattice engineering at atomic precision to catalytic performance.

An Ambipolar BODIPY Derivative for a White Exciplex OLED and Cholesteric Liquid Crystal Laser toward Multifunctional Devices.

PubMed

Chapran, Marian; Angioni, Enrico; Findlay, Neil J; Breig, Benjamin; Cherpak, Vladyslav; Stakhira, Pavlo; Tuttle, Tell; Volyniuk, Dmytro; Grazulevicius, Juozas V; Nastishin, Yuriy A; Lavrentovich, Oleg D; Skabara, Peter J

2017-02-08

A new interface engineering method is demonstrated for the preparation of an efficient white organic light-emitting diode (WOLED) by embedding an ultrathin layer of the novel ambipolar red emissive compound 4,4-difluoro-2,6-di(4-hexylthiopen-2-yl)-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (bThBODIPY) in the exciplex formation region. The compound shows a hole and electron mobility of 3.3 × 10 -4 and 2 × 10 -4 cm 2 V -1 s -1 , respectively, at electric fields higher than 5.3 × 10 5 V cm -1 . The resulting WOLED exhibited a maximum luminance of 6579 cd m -2 with CIE 1931 color coordinates (0.39; 0.35). The bThBODIPY dye is also demonstrated to be an effective laser dye for a cholesteric liquid crystal (ChLC) laser. New construction of the ChLC laser, by which a flat capillary with an optically isotropic dye solution is sandwiched between two dye-free ChLC cells, provides photonic lasing at a wavelength well matched with that of a dye-doped planar ChLC cell.

Tailored Engineering of an Unusual (C4 H9 NH3 )2 (CH3 NH3 )2 Pb3 Br10 Two-Dimensional Multilayered Perovskite Ferroelectric for a High-Performance Photodetector.

PubMed

Li, Lina; Sun, Zhihua; Wang, Peng; Hu, Weida; Wang, Sasa; Ji, Chengmin; Hong, Maochun; Luo, Junhua

2017-09-25

Two-dimensional (2D) layered hybrid perovskites have shown great potential in optoelectronics, owing to their unique physical attributes. However, 2D hybrid perovskite ferroelectrics remain rare. The first hybrid ferroelectric with unusual 2D multilayered perovskite framework, (C 4 H 9 NH 3 ) 2 (CH 3 NH 3 ) 2 Pb 3 Br 10 (1), has been constructed by tailored alloying of the mixed organic cations into 3D prototype of CH 3 NH 3 PbBr 3 . Ferroelectricity is created through molecular reorientation and synergic ordering of organic moieties, which are unprecedented for the known 2D multilayered hybrid perovskites. Single-crystal photodetectors of 1 exhibit fascinating performances, including extremely low dark currents (ca. 10 -12  A), large on/off current ratios (ca. 2.5×10 3 ), and very fast response rate (ca. 150 μs). These merits are superior to integrated detectors of other 2D perovskites, and compete with the most active CH 3 NH 3 PbI 3 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bion-11 Spaceflight Mission

NASA Technical Reports Server (NTRS)

Skidmore, M.

1999-01-01

The Sensors 2000! Program, in support of the Space Life Sciences Payloads Office at NASA Ames Research Center developed a suite of bioinstrumentation hardware for use on the Joint US/Russian Bion I I Biosatellite Mission (December 24, 1996 - January 7, 1997). This spaceflight included 20 separate experiments that were organized into a complimentary and interrelated whole, and performed by teams of US, Russian, and French investigators. Over 40 separate parameters were recorded in-flight on both analog and digital recording media for later analysis. These parameters included; Electromyogram (7 ch), Electrogastrogram, Electrooculogram (2 ch), ECG/EKG, Electroencephlogram (2 ch), single fiber firing of Neurovestibular afferent nerves (7 ch), Tendon Force, Head Motion Velocity (pitch & yaw), P02 (in vivo & ambient), temperature (deep body, skin, & ambient), and multiple animal and spacecraft performance parameters for a total of 45 channels of recorded data. Building on the close cooperation of previous missions, US and Russian engineers jointly developed, integrated, and tested the physiologic instrumentation and data recording system. For the first time US developed hardware replaced elements of the Russian systems resulting in a US/Russian hybrid instrumentation and data system that functioned flawlessly during the 14 day mission.

Non-invasive red light optogenetic pacing and optical coherence microscopy (OCM) imaging for drosophila melanogaster (Conference Presentation)

NASA Astrophysics Data System (ADS)

Men, Jing; Li, Airong; Jerwick, Jason; Tanzi, Rudolph E.; Zhou, Chao

2017-02-01

Cardiac pacing could be a powerful tool for investigating mammalian cardiac electrical conduction systems as well as for treatment of certain cardiac pathologies. However, traditional electrical pacing using pacemaker requires an invasive surgical procedure. Electrical currents from the implanted electrodes can also cause damage to heart tissue, further restricting its utility. Optogenetic pacing has been developed as a promising, non-invasive alternative to electrical stimulation for controlling animal heart rhythms. It induces heart contractions by shining pulsed light on transgene-generated microbial opsins, which in turn activate the light gated ion channels in animal hearts. However, commonly used opsins in optogenetic pacing, such as channelrhodopsin-2 (ChR2), require short light wavelength stimulation (475 nm), which is strongly absorbed and scattered by tissue. Here, we performed optogenetic pacing by expression of recently engineered red-shifted microbial opsins, ReaChR and CsChrimson, in a well-established animal model, Drosophila melanogaster, using the 617 nm stimulation light pulses. The OCM technique enables non-invasive optical imaging of animal hearts with high speed and ultrahigh axial and transverse resolutions. We integrated a customized OCM system with the optical stimulation system to monitor the optogenetic pacing noninvasively. The use of red-sifted opsins enabled deeper penetration of simulating light at lower power, which is promising for applications of optogenetic pacing in mammalian cardiac pathology studies or clinical treatments in the future.

Localised controlled release of simvastatin from porous chitosan-gelatin scaffolds engrafted with simvastatin loaded PLGA-microparticles for bone tissue engineering application.

PubMed

Gentile, Piergiorgio; Nandagiri, Vijay Kumar; Daly, Jacqueline; Chiono, Valeria; Mattu, Clara; Tonda-Turo, Chiara; Ciardelli, Gianluca; Ramtoola, Zebunnissa

2016-02-01

Localised controlled release of simvastatin from porous freeze-dried chitosan-gelatin (CH-G) scaffolds was investigated by incorporating simvastatin loaded poly-(dl-lactide-co-glycolide) acid (PLGA) microparticles (MSIMs) into the scaffolds. MSIMs at 10% w/w simvastatin loading were prepared using a single emulsion-solvent evaporation method. The MSIM optimal amount to be incorporated into the scaffolds was selected by analysing the effect of embedding increasing amounts of blank PLGA microparticles (BL-MPs) on the scaffold physical properties and on the in vitro cell viability using a clonal human osteoblastic cell line (hFOB). Increasing the BL-MP content from 0% to 33.3% w/w showed a significant decrease in swelling degree (from 1245±56% to 570±35%). Scaffold pore size and distribution changed significantly as a function of BL-MP loading. Compressive modulus of scaffolds increased with increasing BL-MP amount up to 16.6% w/w (23.0±1.0kPa). No significant difference in cell viability was observed with increasing BL-MP loading. Based on these results, a content of 16.6% w/w MSIM particles was incorporated successfully in CH-G scaffolds, showing a controlled localised release of simvastatin able to influence the hFOB cell proliferation and the osteoblastic differentiation after 11 days. Copyright © 2015 Elsevier B.V. All rights reserved.

The Global Energy Balance Archive (GEBA) version 2017: a database for worldwide measured surface energy fluxes

NASA Astrophysics Data System (ADS)

Wild, Martin; Ohmura, Atsumu; Schär, Christoph; Müller, Guido; Folini, Doris; Schwarz, Matthias; Zyta Hakuba, Maria; Sanchez-Lorenzo, Arturo

2017-08-01

The Global Energy Balance Archive (GEBA) is a database for the central storage of the worldwide measured energy fluxes at the Earth's surface, maintained at ETH Zurich (Switzerland). This paper documents the status of the GEBA version 2017 dataset, presents the new web interface and user access, and reviews the scientific impact that GEBA data had in various applications. GEBA has continuously been expanded and updated and contains in its 2017 version around 500 000 monthly mean entries of various surface energy balance components measured at 2500 locations. The database contains observations from 15 surface energy flux components, with the most widely measured quantity available in GEBA being the shortwave radiation incident at the Earth's surface (global radiation). Many of the historic records extend over several decades. GEBA contains monthly data from a variety of sources, namely from the World Radiation Data Centre (WRDC) in St. Petersburg, from national weather services, from different research networks (BSRN, ARM, SURFRAD), from peer-reviewed publications, project and data reports, and from personal communications. Quality checks are applied to test for gross errors in the dataset. GEBA has played a key role in various research applications, such as in the quantification of the global energy balance, in the discussion of the anomalous atmospheric shortwave absorption, and in the detection of multi-decadal variations in global radiation, known as global dimming and brightening. GEBA is further extensively used for the evaluation of climate models and satellite-derived surface flux products. On a more applied level, GEBA provides the basis for engineering applications in the context of solar power generation, water management, agricultural production and tourism. GEBA is publicly accessible through the internet via http://www.geba.ethz.ch. Supplementary data are available at https://doi.org/10.1594/PANGAEA.873078.

InChIKey collision resistance: an experimental testing

PubMed Central

2012-01-01

InChIKey is a 27-character compacted (hashed) version of InChI which is intended for Internet and database searching/indexing and is based on an SHA-256 hash of the InChI character string. The first block of InChIKey encodes molecular skeleton while the second block represents various kinds of isomerism (stereo, tautomeric, etc.). InChIKey is designed to be a nearly unique substitute for the parent InChI. However, a single InChIKey may occasionally map to two or more InChI strings (collision). The appearance of collision itself does not compromise the signature as collision-free hashing is impossible; the only viable approach is to set and keep a reasonable level of collision resistance which is sufficient for typical applications. We tested, in computational experiments, how well the real-life InChIKey collision resistance corresponds to the theoretical estimates expected by design. For this purpose, we analyzed the statistical characteristics of InChIKey for datasets of variable size in comparison to the theoretical statistical frequencies. For the relatively short second block, an exhaustive direct testing was performed. We computed and compared to theory the numbers of collisions for the stereoisomers of Spongistatin I (using the whole set of 67,108,864 isomers and its subsets). For the longer first block, we generated, using custom-made software, InChIKeys for more than 3 × 1010 chemical structures. The statistical behavior of this block was tested by comparison of experimental and theoretical frequencies for the various four-letter sequences which may appear in the first block body. From the results of our computational experiments we conclude that the observed characteristics of InChIKey collision resistance are in good agreement with theoretical expectations. PMID:23256896

InChIKey collision resistance: an experimental testing.

PubMed

Pletnev, Igor; Erin, Andrey; McNaught, Alan; Blinov, Kirill; Tchekhovskoi, Dmitrii; Heller, Steve

2012-12-20

InChIKey is a 27-character compacted (hashed) version of InChI which is intended for Internet and database searching/indexing and is based on an SHA-256 hash of the InChI character string. The first block of InChIKey encodes molecular skeleton while the second block represents various kinds of isomerism (stereo, tautomeric, etc.). InChIKey is designed to be a nearly unique substitute for the parent InChI. However, a single InChIKey may occasionally map to two or more InChI strings (collision). The appearance of collision itself does not compromise the signature as collision-free hashing is impossible; the only viable approach is to set and keep a reasonable level of collision resistance which is sufficient for typical applications.We tested, in computational experiments, how well the real-life InChIKey collision resistance corresponds to the theoretical estimates expected by design. For this purpose, we analyzed the statistical characteristics of InChIKey for datasets of variable size in comparison to the theoretical statistical frequencies. For the relatively short second block, an exhaustive direct testing was performed. We computed and compared to theory the numbers of collisions for the stereoisomers of Spongistatin I (using the whole set of 67,108,864 isomers and its subsets). For the longer first block, we generated, using custom-made software, InChIKeys for more than 3 × 1010 chemical structures. The statistical behavior of this block was tested by comparison of experimental and theoretical frequencies for the various four-letter sequences which may appear in the first block body.From the results of our computational experiments we conclude that the observed characteristics of InChIKey collision resistance are in good agreement with theoretical expectations.

Absolute Frequency Measurements with a Set of Transportable HE-NE/CH4 Optical Frequency Standards and Prospects for Future Design and Applications

NASA Astrophysics Data System (ADS)

Gubin, M.; Kovalchuk, E.; Petrukhin, E.; Shelkovnikov, A.; Tyurikov, D.; Gamidov, R.; Erdogan, C.; Sahin, E.; Felder, R.; Gill, P.; Lea, S. N.; Kramer, G.; Lipphardt, B.

2002-04-01

The accumulated results of absolute frequency measurements (AFM) carried out in 1997-2000 with transportable double-mode He-Ne/CH4 optical frequency standards (λ = 3 .39μm) in a collaboration of several laboratories are presented. The performance of this secondary optical frequency standard is estimated on the level of 10-13 (in repeatability), and 1 × 10-14/s (in stability). The next steps towards He-Ne/CH4 standards with one order of magnitude better performance, including devices based on monolithic zerodur resonators, are discussed. Important applications of transportable He-Ne/CH4 optical frequency standards have appeared now due to dramatic progress in the field of optical frequency measurements. Used to stabilize the repetition rate of a Ti:Sa fs laser, these compact secondary standards can transfer their performance into the whole optical range covered by a fs comb. Thus they can play the role of a narrow spectrum interrogative oscillator for super-accurate optical or microwave frequency standards substituting in some tasks a H-maser or oscillators based on cryogenic sapphire resonators.

Analysis of environmental factors impacting the life cycle cost analysis of conventional and fuel cell/battery-powered passenger vehicles. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This report presents the results of the further developments and testing of the Life Cycle Cost (LCC) Model previously developed by Engineering Systems Management, Inc. (ESM) on behalf of the U.S. Department of Energy (DOE) under contract No. DE-AC02-91CH10491. The Model incorporates specific analytical relationships and cost/performance data relevant to internal combustion engine (ICE) powered vehicles, battery powered electric vehicles (BPEVs), and fuel cell/battery-powered electric vehicles (FCEVs).

Tuning of acyl-ACP thioesterase activity directed for tailored fatty acid synthesis.

PubMed

Feng, Yanbin; Zhang, Yunxiu; Wang, Yayue; Liu, Jiao; Liu, Yinghui; Cao, Xupeng; Xue, Song

2018-04-01

Medium-chain fatty acids have attracted significant attention as sources of biofuels in recent years. Acyl-ACP thioesterase, which is considered as the key enzyme to determine the carbon chain length, catalyzes the termination of de novo fatty acid synthesis. Although recombinant medium-chain acyl-ACP thioesterase (TE) affects the fatty acid profile in heterologous cells, tailoring of the fatty acid composition merely by engineering a specific TE is still intractable. In this study, the activity of a C8-C10-specific thioesterase FatB2 from Cuphea hookeriana on C10-ACP was quantified twice as high as that on C8-ACP based on a synthetic C8-C16 acyl-ACP pool in vitro. Whereas in vivo, it was demonstrated that ChFatB2 preferred to accumulate C8 fatty acids with 84.9% composition in the ChFatB2-engineered E. coli strain. To achieve C10 fatty acid production, ChFatB2 was rationally tuned based on structural investigation and enzymatic analysis. An I198E mutant was identified to redistribute the C8-ACP flow, resulting in C10 fatty acid being produced as the principal component at 57.6% of total fatty acids in vivo. It was demonstrated that the activity of TE relative to β-ketoacyl-ACP synthases (KAS) directly determined the fatty acid composition. Our results provide a prospective strategy in tailoring fatty acid synthesis by tuning of TE activities based on TE-ACP interaction.

Technology requirements for future Earth-to-geosynchronous orbit transportation systems. Volume 3: Appendices

NASA Technical Reports Server (NTRS)

Caluori, V. A.; Conrad, R. T.; Jenkins, J. C.

1980-01-01

Technological requirements and forecasts of rocket engine parameters and launch vehicles for future Earth to geosynchronous orbit transportation systems are presented. The parametric performance, weight, and envelope data for the LOX/CH4, fuel cooled, staged combustion cycle and the hydrogen cooled, expander bleed cycle engine concepts are discussed. The costing methodology and ground rules used to develop the engine study are summarized. The weight estimating methodology for winged launched vehicles is described and summary data, used to evaluate and compare weight data for dedicated and integrated O2/H2 subsystems for the SSTO, HLLV and POTV are presented. Detail weights, comparisons, and weight scaling equations are provided.

Transition metal-catalyzed C-H activation reactions: diastereoselectivity and enantioselectivity.

PubMed

Giri, Ramesh; Shi, Bing-Feng; Engle, Keary M; Maugel, Nathan; Yu, Jin-Quan

2009-11-01

This critical review discusses historical and contemporary research in the field of transition metal-catalyzed carbon-hydrogen (C-H) bond activation through the lens of stereoselectivity. Research concerning both diastereoselectivity and enantioselectivity in C-H activation processes is examined, and the application of concepts in this area for the development of novel carbon-carbon and carbon-heteroatom bond-forming reactions is described. Throughout this review, an emphasis is placed on reactions that are (or may soon become) relevant in the realm of organic synthesis (221 references).

Dissociative properties of 1,1,1,2-tetrafluoroethane obtained by computational chemistry

NASA Astrophysics Data System (ADS)

Hayashi, Toshio; Ishikawa, Kenji; Sekine, Makoto; Hori, Masaru

2018-06-01

The electronic properties and dissociative channels of the alternative to the CCl2F2 (CFC-12) refrigerant, 1,1,1,2-tetrafluoroethane (HFC-134a) with a low global warming potential (GWP, 1430), were revealed by computational chemistry. The results show that CF3 + and CHF2 + ions are mainly produced by ionization. The CF3CH2 + ion is produced by ion pair formation and by direct ionization in the energy region higher than approximately 15 eV, but also in small amounts by the ionization of the dissociated CF3CH2 radical. This information is useful for etching process engineers in leading-edge semiconductor manufacturing.

Boosting the power conversion efficiency of perovskite solar cells using self-organized polymeric hole extraction layers with high work function.

PubMed

Lim, Kyung-Geun; Kim, Hak-Beom; Jeong, Jaeki; Kim, Hobeom; Kim, Jin Young; Lee, Tae-Woo

2014-10-08

A self-organized hole extraction layer (SOHEL) with high work function (WF) is designed for energy level alignment with the ionization potential level of CH3 NH3 PbI3 . The SOHEL increases the built-in potential, photocurrent, and power conversion efficiency (PCE) of CH3 NH3 PbI3 perovskite solar cells. Thus, interface engineering of the positive electrode of solution-processed planar heterojunction solar cells using a high-WF SOHEL is a very effective way to achieve high device efficiency (PCE = 11.7% on glass). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A vacuum ultraviolet laser pulsed field ionization-photoion study of methane (CH 4): Determination of the appearance energy of methylium from methane with unprecedented precision and the resulting impact on the bond dissociation energies of CH 4 and CH 4 +

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Yih -Chung; Xiong, Bo; Bross, David H.

Here, we report on the successful implementation of a high-resolution vacuum ultraviolet (VUV) laser pulsed field ionization-photoion (PFI-PI) detection method for the study of unimolecular dissociation of quantum-state- or energy-selected molecular ions. As a test case, we have determined the 0 K appearance energy (AE 0) for the formation of methylium, CH 3 +, from methane, CH 4, as AE 0 (CH 3 +/CH 4) = 14.32271 ± 0.00013 eV. This value has a significantly smaller error limit, but is otherwise consistent with previous laboratory and/or synchrotron-based studies of this dissociative photoionization onset. Furthermore, the sum of the VUV lasermore » PFI-PI spectra obtained for the parent CH 4 + ion and the fragment CH 3 + ions of methane is found to agree with the earlier VUV pulsed field ionization-photoelectron (VUV-PFI-PE) spectrum of methane, providing unambiguous validation of the previous interpretation that the sharp VUV-PFI-PE step observed at the AE 0 (CH 3 +/CH 4) threshold ensues because of higher PFI detection efficiency for fragment CH 3 + than for parent CH 4 +. This, in turn, is a consequence of the underlying high- n Rydberg dissociation mechanism for the dissociative photoionization of CH 4, which was proposed in previous synchrotron-based VUV-PFI-PE and VUV-PFI-PEPICO studies of CH 4. The present highly accurate 0 K dissociative ionization threshold for CH 4 can be utilized to derive accurate values for the bond dissociation energies of methane and methane cation. For methane, the straightforward application of sequential thermochemistry via the positive ion cycle leads to some ambiguity because of two competing VUV-PFI-PE literature values for the ionization energy of methyl radical. The ambiguity is successfully resolved by applying the Active Thermochemical Tables (ATcT) approach, resulting in D 0 (H-CH 3) = 432.463 ± 0.027 kJ/mol and D 0(H-CH 3 +) = 164.701 ± 0.038 kJ/mol.« less

A vacuum ultraviolet laser pulsed field ionization-photoion study of methane (CH 4): Determination of the appearance energy of methylium from methane with unprecedented precision and the resulting impact on the bond dissociation energies of CH 4 and CH 4 +

DOE PAGES

Chang, Yih -Chung; Xiong, Bo; Bross, David H.; ...

2017-03-27

Here, we report on the successful implementation of a high-resolution vacuum ultraviolet (VUV) laser pulsed field ionization-photoion (PFI-PI) detection method for the study of unimolecular dissociation of quantum-state- or energy-selected molecular ions. As a test case, we have determined the 0 K appearance energy (AE 0) for the formation of methylium, CH 3 +, from methane, CH 4, as AE 0 (CH 3 +/CH 4) = 14.32271 ± 0.00013 eV. This value has a significantly smaller error limit, but is otherwise consistent with previous laboratory and/or synchrotron-based studies of this dissociative photoionization onset. Furthermore, the sum of the VUV lasermore » PFI-PI spectra obtained for the parent CH 4 + ion and the fragment CH 3 + ions of methane is found to agree with the earlier VUV pulsed field ionization-photoelectron (VUV-PFI-PE) spectrum of methane, providing unambiguous validation of the previous interpretation that the sharp VUV-PFI-PE step observed at the AE 0 (CH 3 +/CH 4) threshold ensues because of higher PFI detection efficiency for fragment CH 3 + than for parent CH 4 +. This, in turn, is a consequence of the underlying high- n Rydberg dissociation mechanism for the dissociative photoionization of CH 4, which was proposed in previous synchrotron-based VUV-PFI-PE and VUV-PFI-PEPICO studies of CH 4. The present highly accurate 0 K dissociative ionization threshold for CH 4 can be utilized to derive accurate values for the bond dissociation energies of methane and methane cation. For methane, the straightforward application of sequential thermochemistry via the positive ion cycle leads to some ambiguity because of two competing VUV-PFI-PE literature values for the ionization energy of methyl radical. The ambiguity is successfully resolved by applying the Active Thermochemical Tables (ATcT) approach, resulting in D 0 (H-CH 3) = 432.463 ± 0.027 kJ/mol and D 0(H-CH 3 +) = 164.701 ± 0.038 kJ/mol.« less

Computational Science at the Argonne Leadership Computing Facility

NASA Astrophysics Data System (ADS)

Romero, Nichols

2014-03-01

The goal of the Argonne Leadership Computing Facility (ALCF) is to extend the frontiers of science by solving problems that require innovative approaches and the largest-scale computing systems. ALCF's most powerful computer - Mira, an IBM Blue Gene/Q system - has nearly one million cores. How does one program such systems? What software tools are available? Which scientific and engineering applications are able to utilize such levels of parallelism? This talk will address these questions and describe a sampling of projects that are using ALCF systems in their research, including ones in nanoscience, materials science, and chemistry. Finally, the ways to gain access to ALCF resources will be presented. This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under contract DE-AC02-06CH11357.

The Interface between ChE and Mathematics: What Do Students Really Need?

ERIC Educational Resources Information Center

Graham, Michael D.; Ganter, Susan L.

2001-01-01

Summarizes the report given to the Committee on the Undergraduate Program in Mathematics of the Mathematical Association of America (MAA) who is developing new guidelines for instruction in mathematics with a chemical engineering group at Clemson University in order to list specific knowledge and skills in mathematics needed by engineering…

Alternative Fuels Data Center: Methanol

Science.gov Websites

(CH3OH), also known as wood alcohol, is considered an alternative fuel under the Energy Policy Act of 1992. As an engine fuel, methanol has chemical and physical fuel properties similar to ethanol Ethanol Hydrogen Natural Gas Propane Emerging Fuels Fuel Prices Conserve Fuel Idle Reduction Parts &

A Project-based Spiral Curriculum for Introductory Courses in ChE: Part 3. Evaluation.

ERIC Educational Resources Information Center

DiBiasio, David; Comparini, Lisa; Dixon, Anthony G.; Clark, William M.

2001-01-01

Presents the third part of a series on the development and implementation of project-based spiral curriculum in chemical engineering. Focuses on the details of the assessment design, describes the results of the assessment, and draws conclusions about the success of the program. (Contains 18 references.) (ASK)

Assessment of Pneumatic Controller Emission Measurements using a High Volume Sampler at the Oil and Natural Gas Production Pads in Utah

EPA Science Inventory

Oil and Natural Gas (ONG) production facilities have the potential to emit greenhouse gases such as methane (CH4) and other hydrocarbons (HCs) to the atmosphere. ONG production sites have multiple emission sources including storage tank venting, enclosed combustion devices, engin...

Engineered in situ bioremediation of a petroleum hydrocarbon-contaminated aquifer: assessment of mineralization based on alkalinity, inorganic carbon and stable carbon isotope balances

NASA Astrophysics Data System (ADS)

Hunkeler, Daniel; Höhener, Patrick; Bernasconi, Stefano; Zeyer, Josef

1999-04-01

A concept is proposed to assess in situ petroleum hydrocarbon mineralization by combining data on oxidant consumption, production of reduced species, CH 4, alkalinity and dissolved inorganic carbon (DIC) with measurements of stable isotope ratios. The concept was applied to a diesel fuel contaminated aquifer in Menziken, Switzerland, which was treated by engineered in situ bioremediation. In the contaminated aquifer, added oxidants (O 2 and NO 3-) were consumed, elevated concentrations of Fe(II), Mn(II), CH 4, alkalinity and DIC were detected and the DIC was generally depleted in 13C compared to the background. The DIC production was larger than expected based on the consumption of dissolved oxidants and the production of reduced species. Stable carbon isotope balances revealed that the DIC production in the aquifer originated mainly from microbial petroleum hydrocarbon mineralization, and that geochemical reactions such as carbonate dissolution produced little DIC. This suggests that petroleum hydrocarbon mineralization can be underestimated if it is determined based on concentrations of dissolved oxidants and reduced species.

Unique Chernobyl Cranes for Deconstruction Activities in the New Safe Confinement - 13542

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parameswaran, N.A. Vijay; Chornyy, Igor; Owen, Rob

2013-07-01

The devastation left behind from the Chernobyl nuclear power plant (ChNPP) Unit 4 accident which occurred on April 26, 1986 presented unparalleled technical challenges to the world engineering and scientific community. One of the largest tasks that are in progress is the design and construction of the New Safe Confinement (NSC). The NSC is an engineered enclosure for the entire object shelter (OS) that includes a suite of process equipment. The process equipment will be used for the dismantling of the destroyed Chernobyl Nuclear Power Plant (ChNPP) Unit. One of the major mechanical handling systems to be installed in themore » NSC is the Main Cranes System (MCS). The planned decontamination and decommissioning or dismantling (D and D) activities will require the handling of heavily shielded waste disposal casks containing nuclear fuel as well as lifting and transporting extremely large structural elements. These activities, to be performed within the NSC, will require large and sophisticated cranes. The article will focus on the unique design features of the MCS for the D and D activities. (authors)« less

One-Year stable perovskite solar cells by 2D/3D interface engineering

NASA Astrophysics Data System (ADS)

Grancini, G.; Roldán-Carmona, C.; Zimmermann, I.; Mosconi, E.; Lee, X.; Martineau, D.; Narbey, S.; Oswald, F.; de Angelis, F.; Graetzel, M.; Nazeeruddin, Mohammad Khaja

2017-06-01

Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH2)4NH3)2PbI4/CH3NH3PbI3 perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm2 solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells.

One-Year stable perovskite solar cells by 2D/3D interface engineering

PubMed Central

Grancini, G.; Roldán-Carmona, C.; Zimmermann, I.; Mosconi, E.; Lee, X.; Martineau, D.; Narbey, S.; Oswald, F.; De Angelis, F.; Graetzel, M.; Nazeeruddin, Mohammad Khaja

2017-01-01

Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH2)4NH3)2PbI4/CH3NH3PbI3 perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm2 solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells. PMID:28569749

One-Year stable perovskite solar cells by 2D/3D interface engineering.

PubMed

Grancini, G; Roldán-Carmona, C; Zimmermann, I; Mosconi, E; Lee, X; Martineau, D; Narbey, S; Oswald, F; De Angelis, F; Graetzel, M; Nazeeruddin, Mohammad Khaja

2017-06-01

Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH 2 ) 4 NH 3 ) 2 PbI 4 /CH 3 NH 3 PbI 3 perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm 2 solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells.

Impacts of integrated nutrient management on methane emission, global warming potential and carbon storage capacity in rice grown in a northeast India soil.

PubMed

Bharali, Ashmita; Baruah, Kushal Kumar; Baruah, Sunitee Gohain; Bhattacharyya, Pradip

2018-02-01

Rice soil is a source of emission of two major greenhouse gases (methane (CH 4 ) and nitrous oxide (N 2 O)) and a sink of carbon dioxide (CO 2 ). The effect of inorganic fertilizers in combination with various organics (cow dung, green manure (Sesbania aculeata) Azolla compost, rice husk) on CH 4 emission, global warming potential, and soil carbon storage along with crop productivity were studied at university farm under field conditions. The experiment was conducted in a randomized block design for 2 years in a monsoon rice (cv. Ranjit) ecosystem (June-November, 2014 and 2015). Combined application of inorganic (NPK) with Sesbania aculeata resulted in high global warming potential (GWP) of 887.4 kg CO 2 ha -1 and low GWP of 540.6 kg CO 2 ha -1 was recorded from inorganic fertilizer applied field. Irrespective of the type of organic amendments, flag leaf photosynthesis of the rice crop increased over NPK application (control). There was an increase in CH 4 emission from the organic amended fields compared to NPK alone. The combined application of NPK and Azolla compost was effective in the buildup of soil carbon (16.93 g kg -1 ) and capacity of soil carbon storage (28.1 Mg C ha -1 ) with high carbon efficiency ratio (16.9). Azolla compost application along with NPK recorded 15.66% higher CH 4 emission with 27.43% yield increment over control. Azolla compost application significantly enhanced carbon storage of soil and improved the yielding ability of grain (6.55 Mg ha -1 ) over other treatments.

Growth of copper-benzene-1,3,5-tricarboxylate on boron nitride nanotubes and application of the composite in methane sensing

NASA Astrophysics Data System (ADS)

Xiang, Cuili; Chen, Ting; Zhang, Haitao; Zou, Yongjin; Chu, Hailiang; Zhang, Huanzhi; Xu, Fen; Sun, Lixian; Tang, Chengying

2017-12-01

A new composite material based on copper-benzene-1,3,5-tricarboxylate (Cu-BTC) deposited on boron nitride nanotubes (BNNTs) in a hydrothermal process were investigated for methane (CH4) sensing. The composite was characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The Cu-BTC deposited on the BNNTs had an average grain size of 80 nm. The sensing performance of the as-grown product was studied for different concentrations of CH4 (20-200 ppm) at 150 °C. The results revealed that the Cu-BTC/BNNT composite exhibited high sensitivity and selectivity toward CH4. The good sensing performance of the composite was attributed to the high surface area and high affinity of Cu-BTC for CH4, which would allow the composite to act like a preconcentrator for CH4 gas sensing.

Elaboration of copper-oxygen mediated C-H activation chemistry in consideration of future fuel and feedstock generation.

PubMed

Lee, Jung Yoon; Karlin, Kenneth D

2015-04-01

To contribute solutions to current energy concerns, improvements in the efficiency of dioxygen mediated C-H bond cleavage chemistry, for example, selective oxidation of methane to methanol, could minimize losses in natural gas usage or produce feedstocks for fuels. Oxidative C-H activation is also a component of polysaccharide degradation, potentially affording alternative biofuels from abundant biomass. Thus, an understanding of active-site chemistry in copper monooxygenases, those activating strong C-H bonds is briefly reviewed. Then, recent advances in the synthesis-generation and study of various copper-oxygen intermediates are highlighted. Of special interest are cupric-superoxide, Cu-hydroperoxo and Cu-oxy complexes. Such investigations can contribute to an enhanced future application of C-H oxidation or oxygenation processes using air, as concerning societal energy goals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simultaneous identification of multi-combustion-intermediates of alkanol-air flames by femtosecond filament excitation for combustion sensing.

PubMed

Li, Helong; Chu, Wei; Xu, Huailiang; Cheng, Ya; Chin, See-Leang; Yamanouchi, Kaoru; Sun, Hong-Bo

2016-06-02

Laser filamentation produced by the propagation of intense laser pulses in flames is opening up new possibility in application to combustion diagnostics that can provide useful information on understanding combustion processes, enhancing combustion efficiency and reducing pollutant products. Here we present simultaneous identification of multiple combustion intermediates by femtosecond filament excitation for five alkanol-air flames fueled by methanol, ethanol, n-propanol, n-butanol, and n-pentanol. We experimentally demonstrate that the intensities of filament-induced photoemission signals from the combustion intermediates C, C2, CH, CN increase with the increasing number of carbons in the fuel molecules, and the signal ratios between the intermediates (CH/C, CH/C2, CN/C, CH/C2, CN/CH) are different for different alkanol combustion flames. Our observation provides a way for sensing multiple combustion components by femtosecond filament excitation in various combustion conditions that strongly depend on the fuel species.

Periodic mesoporous organosilicas containing interconnected [Si(CH2)]3 rings.

PubMed

Landskron, Kai; Hatton, Benjamin D; Perovic, Doug D; Ozin, Geoffrey A

2003-10-10

A periodic mesoporous organosilica composed of interconnected three-ring [Si(CH2)]3 units built of three SiO2(CH2)2 tetrahedral subunits is reported. It represents the archetype of a previously unknown class of nanocomposite materials in which two bridging organic groups are bound to each silicon atom. It can be obtained with powder and oriented film morphologies. The nanocomposite is self-assembled from the cyclic three-ring silsesquioxane [(EtO)2Si(CH2)]3 precursor and a surfactant mesophase to give a well-ordered mesoporous framework. Low dielectric constants and good mechanical stability of the films were measured, making this material interesting for microelectronic applications. Methylene group reactivity of the three-ring precursor provides entry to a family of nanocomposites, exemplified by the synthesis and self-assembly of [(EtO)2Si(CHR)][(EtO)2Si(CH2)]2 (where R indicates iodine, bromine, or an ethyl group).

Optimal use of tandem biotin and V5 tags in ChIP assays

PubMed Central

Kolodziej, Katarzyna E; Pourfarzad, Farzin; de Boer, Ernie; Krpic, Sanja; Grosveld, Frank; Strouboulis, John

2009-01-01

Background Chromatin immunoprecipitation (ChIP) assays coupled to genome arrays (Chip-on-chip) or massive parallel sequencing (ChIP-seq) lead to the genome wide identification of binding sites of chromatin associated proteins. However, the highly variable quality of antibodies and the availability of epitopes in crosslinked chromatin can compromise genomic ChIP outcomes. Epitope tags have often been used as more reliable alternatives. In addition, we have employed protein in vivo biotinylation tagging as a very high affinity alternative to antibodies. In this paper we describe the optimization of biotinylation tagging for ChIP and its coupling to a known epitope tag in providing a reliable and efficient alternative to antibodies. Results Using the biotin tagged erythroid transcription factor GATA-1 as example, we describe several optimization steps for the application of the high affinity biotin streptavidin system in ChIP. We find that the omission of SDS during sonication, the use of fish skin gelatin as blocking agent and choice of streptavidin beads can lead to significantly improved ChIP enrichments and lower background compared to antibodies. We also show that the V5 epitope tag performs equally well under the conditions worked out for streptavidin ChIP and that it may suffer less from the effects of formaldehyde crosslinking. Conclusion The combined use of the very high affinity biotin tag with the less sensitive to crosslinking V5 tag provides for a flexible ChIP platform with potential implications in ChIP sequencing outcomes. PMID:19196479

Methanol decomposition reactions over a boron-doped graphene supported Ru-Pt catalyst.

PubMed

Damte, Jemal Yimer; Lyu, Shang-Lin; Leggesse, Ermias Girma; Jiang, Jyh Chiang

2018-04-04

The decomposition of methanol is currently attracting research attention due to the potential widespread applications of its end products. In this work, density functional theory (DFT) calculations have been performed to investigate the adsorption and decomposition of methanol on a Ru-Pt/boron doped graphene surface. We find that the most favorable reaction pathway is methanol (CH3OH) decomposition through O-H bond breaking to form methoxide (CH3O) as the initial step, followed by further dehydrogenation steps which generate formaldehyde (CH2O), formyl (CHO), and carbon monoxide (CO). The calculations illustrate that CH3OH and CO groups prefer to adsorb at the Ru-top sites, while CH2OH, CH3O, CH2O, CHO, and H2 groups favor the Ru-Pt bridge sites, indicating the preference of Ru atoms to adsorb the active intermediates or species having lone-pair electrons. Based on the results, it is found that the energy barrier for CH3OH decomposition through the initial O-H bond breaking is less than its desorption energy of 0.95 eV, showing that CH3OH prefers to undergo decomposition to CH3O rather than direct desorption. The study provides in-depth theoretical insights into the potentially enhanced catalytic activity of Ru-Pt/boron doped graphene surfaces for methanol decomposition reactions, thereby contributing to the understanding and designing of an efficient catalyst under optimum conditions.

A New Lead Iodide Perovskite based on Large Organic Cation for Solar Cell Application.

PubMed

Ma, Chunqing; Shen, Dong; Lo, Ming Fai; Lee, Chun-Sing

2018-06-06

Methylammonium (CH3NH3+) and formamidinium ((NH2)2CH+) based lead iodide perovskites are currently the two commonly used organic-inorganic lead iodide perovskites for solar cell application. Till now, there is still no alternative organic cations, which can produce perovskites with bandgaps spanning the visible spectrum (i.e. < 1.7 eV) for solar cell application. Here, a new perovskite using large propane-1,3-diammonium cation (n-Pr(NH3)22+) with a chemical structure of (n-Pr(NH3)2)0.5PbI3 is demonstrated. X-ray diffraction (XRD) result shows that the new perovskite exhibits a three-dimensional (3D), tetragonal phase. The bandgap of the new perovskite is ~ 1.6 eV, which is desirable for photovoltaic application. A (n-Pr(NH3)2)0.5PbI3 perovskite solar cell (PSC) yields a power conversion efficiency (PCE) of 5.1%. More importantly, this new perovskite is composed of larger hydrophobic cation that provides a better moisture resistance compared to CH3NH3PbI3 perovskite. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly Efficient Perovskite Solar Cells with Substantial Reduction of Lead Content.

PubMed

Liu, Chong; Fan, Jiandong; Li, Hongliang; Zhang, Cuiling; Mai, Yaohua

2016-10-18

Despite organometal halide perovskite solar cells have recently exhibited a significant leap in efficiency, the Sn-based perovskite solar cells still suffer from low efficiency. Here, a series homogeneous CH 3 NH 3 Pb (1-x) Sn x I 3 (0 ≤ x ≤ 1) perovskite thin films with full coverage were obtained via solvent engineering. In particular, the intermediate complexes of PbI 2 /(SnI 2 )∙(DMSO) x were proved to retard the crystallization of CH 3 NH 3 SnI 3 , thus allowing the realization of high quality Sn-introduced perovskite thin films. The external quantum efficiency (EQE) of as-prepared solar cells were demonstrated to extend a broad absorption minimum over 50% in the wavelength range from 350 to 950 nm accompanied by a noteworthy absorption onset up to 1050 nm. The CH 3 NH 3 Pb 0.75 Sn 0.25 I 3 perovskite solar cells with inverted structure were consequently realized with maximum power conversion efficiency (PCE) of 14.12%.

Towards mild metal-catalyzed C-H bond activation.

PubMed

Wencel-Delord, Joanna; Dröge, Thomas; Liu, Fan; Glorius, Frank

2011-09-01

Functionalizing traditionally inert carbon-hydrogen bonds represents a powerful transformation in organic synthesis, providing new entries to valuable structural motifs and improving the overall synthetic efficiency. C-H bond activation, however, often necessitates harsh reaction conditions that result in functional group incompatibilities and limited substrate scope. An understanding of the reaction mechanism and rational design of experimental conditions have led to significant improvement in both selectivity and applicability. This critical review summarizes and discusses endeavours towards the development of mild C-H activation methods and wishes to trigger more research towards this goal. In addition, we examine select examples in complex natural product synthesis to demonstrate the synthetic utility of mild C-H functionalization (84 references). This journal is © The Royal Society of Chemistry 2011

Polyacetylene, (CH){sub x}, as an Emerging Material for Solar Cell Applications. Final Technical Report, March 19, 1979 - March 18, 1980

DOE R&D Accomplishments Database

Heeger, A. J.; MacDiarmid, A. G.

1980-06-05

Despite great theoretical and technological interest in polyacetylene, (CH){sub x}, the basic features of its band structure have not been unambiguously resolved. Since photoconductivity and optical absorption data have frequently been used to infer information on the band structure of semiconductors, such measurements were carried out on (CH){sub x}. The main results of an extensive study of the photoconductivity (..delta.. sigma{sub ph}) and absorption coefficient (..cap alpha..) in (CH){sub x} are presented. The absence of photoconductivity in cis-(CH){sub x}, despite the similarity in optical properties indicates that ..delta.. sigma/sub ph/ in trans-(CH){sub x} is induced by isomerization. It is found that isomerization generates states deep inside the gap that act as safe traps for minority carriers and thereby enhance the photoconductivity. Compensation of trans-(CH){sub x} with ammonia appears to decrease the number of safe traps, whereas acceptor doping increases their number. Thus, chemical doping can be used to control the photoconductive response. The energy of safe traps inside the gap is independent of the process used to generate them; indicative of an intrinsic localized defect level in trans-(CH){sub x}. A coherent picture based on the soliton model can explain these results, including the safe trapping.

An ammonium sulfate sensitive chitinase from Streptomyces sp. CS501.

PubMed

Rahman, Md Arifur; Choi, Yun Hee; Pradeep, G C; Yoo, Jin Cheol

2014-12-01

A chitinase from Streptomyces sp. CS501 was isolated from the Korean soil sample, purified by single-step chromatography, and biochemically characterized. The extracellular chitinase (Ch501) was purified to 4.60 fold with yield of 28.74 % using Sepharose Cl-6B column. The molecular mass of Ch501 was approximately 43 kDa as estimated by SDS-PAGE and zymography. The enzyme (Ch501) was found to be stable over a broad pH range (5.0-10.0) and temperature (up to 50 °C), and have an optimum temperature of 60 °C. N-terminal sequence of Ch501 was AAYDDAAAAA. Intriguingly, Ch501 was highly sensitive to ammonium sulfate but it's completely suppressed activity was recovered after desalting out. TLC analysis of Ch501 showed the production of N-acetyl D-glucosamine (GlcNAc) and Diacetylchitobiose (GlcNAc)2, as a principal hydrolyzed product. Ch501 shows antifungal activity against Fusarium solani and Aspergillus brasiliensis, which can be used for the biological control of fungus. As has been simple in purification, stable in a broad range of pH, ability to produce oligosaccharides, and antifungal activity showed that Ch501 has potential applications in industries as for chitooligosaccharides production used as prebiotics and/or for the biological control of plant pathogens in agriculture.

Collisional excitation of CH2 rotational/fine-structure levels by helium

NASA Astrophysics Data System (ADS)

Dagdigian, P. J.; Lique, F.

2018-02-01

Accurate determination of the abundance of CH2 in interstellar media relies on both radiative and collisional rate coefficients. We investigate here the rotational/fine-structure excitation of CH2 induced by collisions with He. We employ a recoupling technique to generate fine-structure-resolved cross-sections and rate coefficients from close coupling spin-free scattering calculations. The calculations are based on a recent, high-accuracy CH2-He potential energy surface computed at the coupled clusters level of theory. The collisional cross-section calculations are performed for all fine-structure transitions among the first 22 and 24 energy levels of ortho- and para-CH2, respectively, and for temperatures up to 300 K. As a first application, we simulate the excitation of CH2 in typical molecular clouds. The excitation temperatures of the CH2 lines are found to be small at typical densities of molecular clouds, showing that the non-local thermodynamic equilibrium approach has to be used to analyse interstellar spectra. We also found that the fine-structure lines connected with the 404 - 313 and 505 - 414 rotational transitions show possible maser emissions so that they can be easily seen in emission. These calculations show that CH2 may have to be detected mainly through absorption spectra.

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

PubMed Central

Chen, Xiaoyun; Abdullah, Hairus; Kuo, Dong-Hau

2017-01-01

A conservative CO2-Methanol (CH3OH) regeneration cycle, to capture and reutilize the greenhouse gas of CO2 by aqueous hydrogenation for industry-useful CH3OH and to convert aqueous CH3OH solution by dehydrogenation for the clean energy of hydrogen (H2), is demonstrated at normal temperature and pressure (NTP) with two kinds of CuMnOS nanoflower catalysts. The [Cu+]-high CuMnOS led to a CH3OH yield of 21.1 mmol·g−1catal.·h−1 in the CuMnOS-CO2-H2O system and the other [Cu+]-low one had a H2 yield of 7.65 mmol·g−1catal.·h−1 in the CuMnOS-CH3OH-H2O system. The successful redox reactions at NTP rely on active lattice oxygen of CuMnOS catalysts and its charge (hole or electron) transfer ability between Cu+ and Cu2+. The CO2-hydrogenated CH3OH in aqueous solution is not only a fuel but also an ideal liquid hydrogen storage system for transportation application. PMID:28117456

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

NASA Astrophysics Data System (ADS)

Chen, Xiaoyun; Abdullah, Hairus; Kuo, Dong-Hau

2017-01-01

A conservative CO2-Methanol (CH3OH) regeneration cycle, to capture and reutilize the greenhouse gas of CO2 by aqueous hydrogenation for industry-useful CH3OH and to convert aqueous CH3OH solution by dehydrogenation for the clean energy of hydrogen (H2), is demonstrated at normal temperature and pressure (NTP) with two kinds of CuMnOS nanoflower catalysts. The [Cu+]-high CuMnOS led to a CH3OH yield of 21.1 mmol·g-1catal.·h-1 in the CuMnOS-CO2-H2O system and the other [Cu+]-low one had a H2 yield of 7.65 mmol·g-1catal.·h-1 in the CuMnOS-CH3OH-H2O system. The successful redox reactions at NTP rely on active lattice oxygen of CuMnOS catalysts and its charge (hole or electron) transfer ability between Cu+ and Cu2+. The CO2-hydrogenated CH3OH in aqueous solution is not only a fuel but also an ideal liquid hydrogen storage system for transportation application.

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions.

PubMed

Chen, Xiaoyun; Abdullah, Hairus; Kuo, Dong-Hau

2017-01-24

A conservative CO 2 -Methanol (CH 3 OH) regeneration cycle, to capture and reutilize the greenhouse gas of CO 2 by aqueous hydrogenation for industry-useful CH 3 OH and to convert aqueous CH 3 OH solution by dehydrogenation for the clean energy of hydrogen (H 2 ), is demonstrated at normal temperature and pressure (NTP) with two kinds of CuMnOS nanoflower catalysts. The [Cu + ]-high CuMnOS led to a CH 3 OH yield of 21.1 mmol·g -1 catal.·h -1 in the CuMnOS-CO 2 -H 2 O system and the other [Cu + ]-low one had a H 2 yield of 7.65 mmol·g -1 catal.·h -1 in the CuMnOS-CH 3 OH-H 2 O system. The successful redox reactions at NTP rely on active lattice oxygen of CuMnOS catalysts and its charge (hole or electron) transfer ability between Cu + and Cu 2+ . The CO 2 -hydrogenated CH 3 OH in aqueous solution is not only a fuel but also an ideal liquid hydrogen storage system for transportation application.

Copper-promoted sulfenylation of sp2 C-H bonds.

PubMed

Tran, Ly Dieu; Popov, Ilya; Daugulis, Olafs

2012-11-07

An auxiliary-assisted, copper catalyzed or promoted sulfenylation of benzoic acid derivative β-C-H bonds and benzylamine derivative γ-C-H bonds has been developed. The method employs disulfide reagents, copper(II) acetate, and DMSO solvent at 90-130 °C. Application of this methodology to the direct trifluoromethylsulfenylation of C-H bonds was demonstrated.

Development and Hotfire Testing of Additively Manufactured Copper Combustion Chambers for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Gradl, Paul R.; Greene, Sandy; Protz, Chris

2017-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM), commonly referred to as additive manufacturing (AM). The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for GRCop-84 (a NASA Glenn Research Center-developed copper, chrome, niobium alloy) commensurate with powder bed AM, evaluate bimetallic deposition, and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. To advance the processes further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic AM chambers. In addition to the LCUSP program, NASA’s Marshall Space Flight Center (MSFC) has completed a series of development programs and hot-fire tests to demonstrate SLM GRCop-84 and other AM techniques. MSFC’s efforts include a 4,000 pounds-force thrust liquid oxygen/methane (LOX/CH4) combustion chamber. Small thrust chambers for 1,200 pounds-force LOX/hydrogen (H2) applications have also been designed and fabricated with SLM GRCop-84. Similar chambers have also completed development with an Inconel 625 jacket bonded to the GRCop-84 material, evaluating direct metal deposition (DMD) laser- and arc-based techniques. The same technologies for these lower thrust applications are being applied to 25,000-35,000 pounds-force main combustion chamber (MCC) designs. This paper describes the design, development, manufacturing and testing of these numerous combustion chambers, and the associated lessons learned throughout their design and development processes.

Straw enhanced CO2 and CH4 but decreased N2O emissions from flooded paddy soils: Changes in microbial community compositions

NASA Astrophysics Data System (ADS)

Wang, Ning; Yu, Jian-Guang; Zhao, Ya-Hui; Chang, Zhi-Zhou; Shi, Xiao-Xia; Ma, Lena Q.; Li, Hong-Bo

2018-02-01

To explore microbial mechanisms of straw-induced changes in CO2, CH4, and N2O emissions from paddy field, wheat straw was amended to two paddy soils from Taizhou (TZ) and Yixing (YX), China for 60 d under flooded condition. Illumia sequencing was used to characterize shift in bacterial community compositions. Compared to control, 1-5% straw amendment significantly elevated CO2 and CH4 emissions with higher increase at higher application rates, mainly due to increased soil DOC concentrations. In contrast, straw amendment decreased N2O emission. Considering CO2, CH4, and N2O emissions as a whole, an overall increase in global warming potential was observed with straw amendment. Total CO2 and CH4 emissions from straw-amended soils were significantly higher for YX than TZ soil, suggesting that straw-induced greenhouse gas emissions depended on soil characteristics. The abundance of C-turnover bacteria Firmicutes increased from 28-41% to 54-77% with straw amendment, thereby increasing CO2 and CH4 emissions. However, straw amendment reduced the abundance of denitrifying bacteria Proteobacteria from 18% to 7.2-13% or increased the abundance of N2O reducing bacteria Clostridium from 7.6-11% to 13-30%, thereby decreasing N2O emission. The results suggested straw amendment strongly influenced greenhouse gas emissions via alerting soil properties and bacterial community compositions. Future field application is needed to ascertain the effects of straw return on greenhouse gas emissions.

Climate and health relevant emissions from in-use Indian three-wheelers fueled by natural gas and gasoline.

PubMed

Reynolds, Conor C O; Grieshop, Andrew P; Kandlikar, Milind

2011-03-15

Auto-rickshaws in India use different fuels and engine technologies, with varying emissions and implications for air quality and climate change. Chassis dynamometer emission testing was conducted on 30 in-use auto-rickshaws to quantify the impact of switching from gasoline to compressed natural gas (CNG) in spark-ignition engines. Thirteen test vehicles had two-stroke CNG engines (CNG-2S) and 17 had four-stroke CNG engines (CNG-4S), of which 11 were dual-fuel and operable on a back-up gasoline (petrol) system (PET-4S). Fuel-based emission factors were determined for gaseous pollutants (CO(2), CH(4), NO(X), THC, and CO) and fine particulate matter (PM(2.5)). Intervehicle variability was high, and for most pollutants there was no significant difference (95% confidence level) between "old" (1998-2001) and "new" (2007-2009) age-groups within a given fuel-technology class. Mean fuel-based PM(2.5) emission factor (mean (95% confidence interval)) for CNG-2S (14.2 g kg(-1) (6.2-26.7)) was almost 30 times higher than for CNG-4S (0.5 g kg(-1) (0.3-0.9)) and 12 times higher than for PET-4S (1.2 g kg(-1) (0.8-1.7)). Global warming commitment associated with emissions from CNG-2S was more than twice that from CNG-4S or PET-4S, due mostly to CH(4) emissions. Comprehensive measurements and data should drive policy interventions rather than assumptions about the impacts of clean fuels.

The Kinetic Nonequilibrium Processes in the Internal Flow and in the Plume of Subsonic and Supersonic Aircrafts

NASA Technical Reports Server (NTRS)

Starik, Alexander M.

1997-01-01

(1) Our results show that under combustion of thermal destruction products of n-C8H18, and other hydrocarbon fuels with air at the equivalent ratio -0.5 and less the chemical equilibrium is not realized at the exit plane of combustion chamber and in the gas turbine and nozzle for most of small components such as NO2, NO3, HNO, HNO2, HNO3, N(x)H(y), HO2, OH. The chemical equilibrium is not realized in the internal flow of ramjet hydrogen combustion engine too. So at the nozzle exit plane both of gas-turbine hydrocarbon combustion engine and of ramjet hydrogen combustion engine the relatively large values of concentration of such small components as NO3, HNO2, N2O, HNO3, HNO, NH, N2H, HO2, H2O2 may be realized. The exact definition of these component concentration as well as concentration of NO(x), OH, SO2, O, H, H2, H2O at the nozzle exit plane is very important for plume chemistry. (2) The results which were obtained for subsonic and hypersonic aircrafts indicate on the considerable change of the composition of the gas mixture along the plume. This change can be caused not only by the mixture of combustion products with the atmosphere air but by proceeding of whole complex of nonequilibrium photochemical reactions. The photodissociation processes begin to influence on the formation of the free atoms and radicals at flight altitude H greater than or equal to 18 km. Neglect of these processes can result in essential (up to 10(exp 4) times) mistakes of values gamma(sub OH), gamma(sub O), gamma(sub H), gamma(sub HSO3) and some products of CFC's disintegration. It was found that penetration of Cl-containing species from the atmosphere into the exhaust flow and its interaction with nitrogen oxides leads to essential increasing of the concentration of Cl, Cl2, ClO2, ClNO3, CH3Cl and sometimes HCl and the decreasing of ClO concentration by comparison with background values. The results of our analysis show that the plume aircraft with both hydrocarbon and hydrogen combustion engine may be source of various pollutant components such as HNO, HNO4,ClO2, CH3NO2, CH3NO3, CH2O, Cl, H2O2, but not only NO, NO2, HNO2, HNO3, N2O5, SO2, SO3, H2SO4 as it was supposed before.

Effects of tillage and nitrogen fertilizers on CH4 and CO2 emissions and soil organic carbon in paddy fields of central China.

PubMed

Cheng-Fang, Li; Dan-Na, Zhou; Zhi-Kui, Kou; Zhi-Sheng, Zhang; Jin-Ping, Wang; Ming-Li, Cai; Cou-Gui, Cao

2012-01-01

Quantifying carbon (C) sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT) and no-tillage (NT)] and the application of nitrogen (N) fertilizer (0 and 210 kg N ha(-1)) on fluxes of CH(4) and CO(2), and soil organic C (SOC) sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH(4) emissions by 13%-66% and SOC by 21%-94% irrespective of soil sampling depths, but had no effect on CO(2) emissions in either year. Tillage significantly affected CH(4) and CO(2) emissions, where NT significantly decreased CH(4) emissions by 10%-36% but increased CO(2) emissions by 22%-40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%-48% in the 0-5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0-20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered.

Efficacy of the combined application of chitosan and Locust Bean Gum with different citrus essential oils to control postharvest spoilage caused by Aspergillus flavus in dates.

PubMed

Aloui, Hajer; Khwaldia, Khaoula; Licciardello, Fabio; Mazzaglia, Agata; Muratore, Giuseppe; Hamdi, Moktar; Restuccia, Cristina

2014-01-17

This study reports the efficacy of the combined application of chitosan (CH) and Locust Bean Gum (LBG) in combination with different citrus essential oils (EOs) to inhibit Aspergillus flavus in vitro and on artificially infected dates for a storage period of 12 days. The effect of these treatments on the fruits' sensory characteristics was evaluated to verify the complete absence of off-odours and off-flavours. Bergamot EO was the most effective in reducing mycelial growth, followed by bitter orange EO. Both bergamot and bitter orange oils significantly reduced conidial germination and a complete inhibition was obtained at concentrations higher than 2%. The mixtures based on CH-2% (v/v) bergamot EO or CH-2% (v/v) bitter orange EO proved to be the most effective coatings to reduce conidial germination resulting in an 87-90% inhibition compared with the control. In fruit decay assays coatings based on CH incorporating citrus oils were able to reduce fungal decay in the range of 52-62% at day 12. The study results and the complete absence of off-flavours and off-odours demonstrate the potential of CH coatings carrying citrus EOs at sub-inhibitory concentrations to control postharvest growth of A. flavus in dates. Copyright © 2013 Elsevier B.V. All rights reserved.

ATLAS of Biochemistry: A Repository of All Possible Biochemical Reactions for Synthetic Biology and Metabolic Engineering Studies.

PubMed

Hadadi, Noushin; Hafner, Jasmin; Shajkofci, Adrian; Zisaki, Aikaterini; Hatzimanikatis, Vassily

2016-10-21

Because the complexity of metabolism cannot be intuitively understood or analyzed, computational methods are indispensable for studying biochemistry and deepening our understanding of cellular metabolism to promote new discoveries. We used the computational framework BNICE.ch along with cheminformatic tools to assemble the whole theoretical reactome from the known metabolome through expansion of the known biochemistry presented in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. We constructed the ATLAS of Biochemistry, a database of all theoretical biochemical reactions based on known biochemical principles and compounds. ATLAS includes more than 130 000 hypothetical enzymatic reactions that connect two or more KEGG metabolites through novel enzymatic reactions that have never been reported to occur in living organisms. Moreover, ATLAS reactions integrate 42% of KEGG metabolites that are not currently present in any KEGG reaction into one or more novel enzymatic reactions. The generated repository of information is organized in a Web-based database ( http://lcsb-databases.epfl.ch/atlas/ ) that allows the user to search for all possible routes from any substrate compound to any product. The resulting pathways involve known and novel enzymatic steps that may indicate unidentified enzymatic activities and provide potential targets for protein engineering. Our approach of introducing novel biochemistry into pathway design and associated databases will be important for synthetic biology and metabolic engineering.

Enhancing Perovskite Solar Cell Performance by Interface Engineering Using CH3NH3PbBr0.9I2.1 Quantum Dots.

PubMed

Cha, Mingyang; Da, Peimei; Wang, Jun; Wang, Weiyi; Chen, Zhanghai; Xiu, Faxian; Zheng, Gengfeng; Wang, Zhong-Sheng

2016-07-13

To improve the interfacial charge transfer that is crucial to the performance of perovskite solar cells, the interface engineering in a device should be rationally designed. Here we have developed an interface engineering method to tune the photovoltaic performance of planar-heterojunction perovskite solar cells by incorporating MAPbBr3-xIx (MA = CH3NH3) quantum dots (QDs) between the MAPbI3 perovskite film and the hole-transporting material (HTM) layer. By adjustment of the Br:I ratio, the as-synthesized MAPbBr3-xIx QDs show tunable fluorescence and band edge positions. When the valence band (VB) edge of MAPbBr3-xIx QDs is located below that of the MAPbI3 perovskite, the hole transfer from the MAPbI3 perovskite film to the HTM layer is hindered, and hence, the power conversion efficiency decreases. In contrast, when the VB edge of MAPbBr3-xIx QDs is located between the VB edge of the MAPbI3 perovskite film and the highest occupied molecular orbital of the HTM layer, the hole transfer from the MAPbI3 perovskite film to the HTM layer is well-facilitated, resulting in significant improvements in the fill factor, short-circuit photocurrent, and power conversion efficiency.

Synthesis of permethyldodecaborate and paramagnetic dodecaborate salt

DOEpatents

Hawthorne, M. Frederick; Peymann, Toralf

2002-01-01

The dodecamethyl closo-borane dianion [closo-B.sub.12 (CH.sub.3).sub.12 ].sup.2- and anion [closo-B.sub.12 (CH.sub.3).sub.12 ].sup.- were synthesized and characterized. Dodecamethyl-closo dodecaborate (2-) was produced from [closo-B.sub.12 H.sub.12 ].sup.2-, using trimethylaluminum, and methyl iodide and modified Friedel-Crafts reaction conditions. The anion was produced from the dianion by chemical oxidation using ceric (4) ammonium nitrate in acetonitrile. The anion and dianion were both characterized by .sup.1 H and .sup.11 B NMR spectroscopy, high-resolution fast atom bombardment (FAB) mass spectrometry, cyclic voltammetry, and single-crystal X-ray diffraction. The "camouflaged" polyhedral borane anion [closo-B.sub.12 (CH.sub.3).sub.12 ].sup.2-, can be used as a precursor to materials that offer a broad spectrum of novel applications ranging from drug applications and supramolecular chemistry to use as a weakly-coordinating dianion.

The ISMARA client

PubMed Central

Ioannidis, Vassilios; van Nimwegen, Erik; Stockinger, Heinz

2016-01-01

ISMARA ( ismara.unibas.ch) automatically infers the key regulators and regulatory interactions from high-throughput gene expression or chromatin state data. However, given the large sizes of current next generation sequencing (NGS) datasets, data uploading times are a major bottleneck. Additionally, for proprietary data, users may be uncomfortable with uploading entire raw datasets to an external server. Both these problems could be alleviated by providing a means by which users could pre-process their raw data locally, transferring only a small summary file to the ISMARA server. We developed a stand-alone client application that pre-processes large input files (RNA-seq or ChIP-seq data) on the user's computer for performing ISMARA analysis in a completely automated manner, including uploading of small processed summary files to the ISMARA server. This reduces file sizes by up to a factor of 1000, and upload times from many hours to mere seconds. The client application is available from ismara.unibas.ch/ISMARA/client. PMID:28232860

Using carbon isotope fractionation for an improved quantification of CH4 oxidation efficiency in Arctic peatlands

NASA Astrophysics Data System (ADS)

Preuss, I.; Knoblauch, C.; Gebert, J.; Pfeiffer, E.-M.

2012-04-01

Much research effort is focused on identifying global CH4 sources and sinks to estimate their current and potential strength in response to land-use change and global warming. Aerobic CH4 oxidation is regarded as the key process reducing the strength of CH4 emissions in wetlands, but is hitherto difficult to quantify. Recent studies quantify the efficiency of CH4 oxidation based on CH4 stable isotope signatures. The approach utilizes the fact that a significant isotope fractionation occurs when CH4 is oxidized. Moreover, it also considers isotope fractionation by diffusion. For field applications the 'open-system equation' is applied to determine the CH4 oxidation efficiency: fox = (δE - δP)/ (αox - αtrans) where fox is the fraction of CH4 oxidized; δE is δ13C of emitted CH4; δP is δ13C of produced CH4; αox is the isotopic fractionation factor of oxidation; αtrans is the isotopic fractionation factor of transport. We quantified CH4 oxidation in polygonal tundra soils of Russia's Lena River Delta analyzing depth profiles of CH4 concentrations and stable isotope signatures. Therefore, both fractionation factors αox and αtrans were determined for three polygon centers with differing water table positions and a polygon rim. While most previous studies on landfill cover soils have assumed a gas transport dominated by advection (αtrans = 1), other CH4 transport mechanisms as diffusion have to be considered in peatlands and αtrans exceeds a value of 1. At our study we determined αtrans = 1.013 ± 0.003 for CH4 when diffusion is the predominant transport mechanism. Furthermore, results showed that αox differs widely between sites and horizons (αox = 1.013 ± 0.012) and has to be determined for each case. The impact of both fractionation factors on the quantification of CH4 oxidation was estimated by considering both the potential diffusion rate at different water contents and potential oxidation rates. Calculations for a water saturated tundra soil indicated a CH4 oxidation efficiency of 88% in the upper horizon. Using carbon isotope fractionation improves the in situ quantification of CH4 oxidation in wetlands and thus the assessment of current and potential CH4 sources and sinks in these ecosystems.

Controllable poly-crystalline bilayered and multilayered graphene film growth by reciprocal chemical vapor deposition

NASA Astrophysics Data System (ADS)

Wu, Qinke; Jung, Seong Jun; Jang, Sung Kyu; Lee, Joohyun; Jeon, Insu; Suh, Hwansoo; Kim, Yong Ho; Lee, Young Hee; Lee, Sungjoo; Song, Young Jae

2015-06-01

We report the selective growth of large-area bilayered graphene film and multilayered graphene film on copper. This growth was achieved by introducing a reciprocal chemical vapor deposition (CVD) process that took advantage of an intermediate h-BN layer as a sacrificial template for graphene growth. A thin h-BN film, initially grown on the copper substrate using CVD methods, was locally etched away during the subsequent graphene growth under residual H2 and CH4 gas flows. Etching of the h-BN layer formed a channel that permitted the growth of additional graphene adlayers below the existing graphene layer. Bilayered graphene typically covers an entire Cu foil with domain sizes of 10-50 μm, whereas multilayered graphene can be epitaxially grown to form islands a few hundreds of microns in size. This new mechanism, in which graphene growth proceeded simultaneously with h-BN etching, suggests a potential approach to control graphene layers for engineering the band structures of large-area graphene for electronic device applications.We report the selective growth of large-area bilayered graphene film and multilayered graphene film on copper. This growth was achieved by introducing a reciprocal chemical vapor deposition (CVD) process that took advantage of an intermediate h-BN layer as a sacrificial template for graphene growth. A thin h-BN film, initially grown on the copper substrate using CVD methods, was locally etched away during the subsequent graphene growth under residual H2 and CH4 gas flows. Etching of the h-BN layer formed a channel that permitted the growth of additional graphene adlayers below the existing graphene layer. Bilayered graphene typically covers an entire Cu foil with domain sizes of 10-50 μm, whereas multilayered graphene can be epitaxially grown to form islands a few hundreds of microns in size. This new mechanism, in which graphene growth proceeded simultaneously with h-BN etching, suggests a potential approach to control graphene layers for engineering the band structures of large-area graphene for electronic device applications. Electronic supplementary information (ESI) available: The growth conditions, statistical studies of OM images and high-resolution STM/TEM measurements for multi-/bi-layered graphene are discussed in detail. See DOI: 10.1039/c5nr02716k

Hippocampal “cholinergic interneurons” visualized with the choline acetyltransferase promoter: anatomical distribution, intrinsic membrane properties, neurochemical characteristics, and capacity for cholinergic modulation

PubMed Central

Yi, Feng; Catudio-Garrett, Elizabeth; Gábriel, Robert; Wilhelm, Marta; Erdelyi, Ferenc; Szabo, Gabor; Deisseroth, Karl; Lawrence, Josh

2015-01-01

Release of acetylcholine (ACh) in the hippocampus (HC) occurs during exploration, arousal, and learning. Although the medial septum-diagonal band of Broca (MS-DBB) is the major extrinsic source of cholinergic input to the HC, cholinergic neurons intrinsic to the HC also exist but remain poorly understood. Here, ChAT-tauGFP and ChAT-CRE/Rosa26YFP (ChAT-Rosa) mice were examined in HC. The HC of ChAT-tauGFP mice was densely innervated with GFP-positive axons, often accompanied by large GFP-positive structures, some of which were Neurotrace/DAPI-negative and likely represent large axon terminals. In the HC of ChAT-Rosa mice, ChAT-YFP cells were Neurotrace-positive and more abundant in CA3 and dentate gyrus than CA1 with partial overlap with calretinin/VIP. Moreover, an anti-ChAT antibody consistently showed ChAT immunoreactivity in ChAT-YFP cells from MS-DBB but rarely from HC. Furthermore, ChAT-YFP cells from CA1 stratum radiatum/stratum lacunosum moleculare (SR/SLM) exhibited a stuttering firing phenotype but a delayed firing phenotype in stratum pyramidale (SP) of CA3. Input resistance and capacitance were also different between CA1 SR/LM and CA3 SP ChAT-YFP cells. Bath application of ACh increased firing frequency in all ChAT-YFP cells; however, cholinergic modulation was larger in CA1 SR/SLM than CA3 SP ChAT-YFP cells. Finally, CA3 SP ChAT-YFP cells exhibited a wider AP half-width and weaker cholinergic modulation than YFP-negative CA3 pyramidal cells. Consistent with CRE expression in a subpopulation of principal cells, optogenetic stimulation evoked glutamatergic postsynaptic currents in CA1 SR/SLM interneurons. In conclusion, the presence of fluorescently labeled hippocampal cells common to both ChAT-tauGFP and ChAT-Rosa mice are in good agreement with previous reports on the existence of cholinergic interneurons, but both transgenic mouse lines exhibited unexpected anatomical features that departed considerably from earlier observations. PMID:25798106

The Description and Validation of a Computationally-Efficient CH4-CO-OH (ECCOH) Module for 3D Model Applications

NASA Technical Reports Server (NTRS)

Elshorbany, Yasin F.; Duncan, Bryan N.; Strode, Sarah A.; Wang, James S.; Kouatchou, Jules

2015-01-01

We present the Efficient CH4-CO-OH Module (ECCOH) that allows for the simulation of the methane, carbon monoxide and hydroxyl radical (CH4-CO-OH cycle, within a chemistry climate model, carbon cycle model, or earth system model. The computational efficiency of the module allows many multi-decadal, sensitivity simulations of the CH4-CO-OH cycle, which primarily determines the global tropospheric oxidizing capacity. This capability is important for capturing the nonlinear feedbacks of the CH4-CO-OH system and understanding the perturbations to relatively long-lived methane and the concomitant impacts on climate. We implemented the ECCOH module into the NASA GEOS-5 Atmospheric Global Circulation Model (AGCM), performed multiple sensitivity simulations of the CH4-CO-OH system over two decades, and evaluated the model output with surface and satellite datasets of methane and CO. The favorable comparison of output from the ECCOH module (as configured in the GEOS-5 AGCM) with observations demonstrates the fidelity of the module for use in scientific research.

The Description and Validation of a Computationally-Efficient CH4-CO-OH (ECCOHv1.01) Chemistry Module for 3D Model Applications

NASA Technical Reports Server (NTRS)

Elshorbany, Yasin F.; Duncan, Bryan N.; Strode, Sarah A.; Wang, James S.; Kouatchou, Jules

2016-01-01

We present the Efficient CH4-CO-OH (ECCOH) chemistry module that allows for the simulation of the methane, carbon monoxide, and hydroxyl radical (CH4-CO- OH) system, within a chemistry climate model, carbon cycle model, or Earth system model. The computational efficiency of the module allows many multi-decadal sensitivity simulations of the CH4-CO-OH system, which primarily determines the global atmospheric oxidizing capacity. This capability is important for capturing the nonlinear feedbacks of the CH4-CO-OH system and understanding the perturbations to methane, CO, and OH, and the concomitant impacts on climate. We implemented the ECCOH chemistry module in the NASA GEOS-5 atmospheric global circulation model (AGCM), performed multiple sensitivity simulations of the CH4-CO-OH system over 2 decades, and evaluated the model output with surface and satellite data sets of methane and CO. The favorable comparison of output from the ECCOH chemistry module (as configured in the GEOS- 5 AGCM) with observations demonstrates the fidelity of the module for use in scientific research.

Invited review: Large-scale indirect measurements for enteric methane emissions in dairy cattle: A review of proxies and their potential for use in management and breeding decisions.

PubMed

Negussie, E; de Haas, Y; Dehareng, F; Dewhurst, R J; Dijkstra, J; Gengler, N; Morgavi, D P; Soyeurt, H; van Gastelen, S; Yan, T; Biscarini, F

2017-04-01

Efforts to reduce the carbon footprint of milk production through selection and management of low-emitting cows require accurate and large-scale measurements of methane (CH 4 ) emissions from individual cows. Several techniques have been developed to measure CH 4 in a research setting but most are not suitable for large-scale recording on farm. Several groups have explored proxies (i.e., indicators or indirect traits) for CH 4 ; ideally these should be accurate, inexpensive, and amenable to being recorded individually on a large scale. This review (1) systematically describes the biological basis of current potential CH 4 proxies for dairy cattle; (2) assesses the accuracy and predictive power of single proxies and determines the added value of combining proxies; (3) provides a critical evaluation of the relative merit of the main proxies in terms of their simplicity, cost, accuracy, invasiveness, and throughput; and (4) discusses their suitability as selection traits. The proxies range from simple and low-cost measurements such as body weight and high-throughput milk mid-infrared spectroscopy (MIR) to more challenging measures such as rumen morphology, rumen metabolites, or microbiome profiling. Proxies based on rumen samples are generally poor to moderately accurate predictors of CH 4 , and are costly and difficult to measure routinely on-farm. Proxies related to body weight or milk yield and composition, on the other hand, are relatively simple, inexpensive, and high throughput, and are easier to implement in practice. In particular, milk MIR, along with covariates such as lactation stage, are a promising option for prediction of CH 4 emission in dairy cows. No single proxy was found to accurately predict CH 4 , and combinations of 2 or more proxies are likely to be a better solution. Combining proxies can increase the accuracy of predictions by 15 to 35%, mainly because different proxies describe independent sources of variation in CH 4 and one proxy can correct for shortcomings in the other(s). The most important applications of CH 4 proxies are in dairy cattle management and breeding for lower environmental impact. When breeding for traits of lower environmental impact, single or multiple proxies can be used as indirect criteria for the breeding objective, but care should be taken to avoid unfavorable correlated responses. Finally, although combinations of proxies appear to provide the most accurate estimates of CH 4 , the greatest limitation today is the lack of robustness in their general applicability. Future efforts should therefore be directed toward developing combinations of proxies that are robust and applicable across diverse production systems and environments. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Structural differences between glycosylated, disulfide-linked heterodimeric Knob-into-Hole Fc fragment and its homodimeric Knob-Knob and Hole-Hole side products.

PubMed

Kuglstatter, A; Stihle, M; Neumann, C; Müller, C; Schaefer, W; Klein, C; Benz, J

2017-09-01

An increasing number of bispecific therapeutic antibodies are progressing through clinical development. The Knob-into-Hole (KiH) technology uses complementary mutations in the CH3 region of the antibody Fc fragment to achieve heavy chain heterodimerization. Here we describe the X-ray crystal structures of glycosylated and disulfide-engineered heterodimeric KiH Fc fragment and its homodimeric Knob-Knob and Hole-Hole side products. The heterodimer structure confirms the KiH design principle and supports the hypothesis that glycosylation stabilizes a closed Fc conformation. Both homodimer structures show parallel Fc fragment architectures, in contrast to recently reported crystal structures of the corresponding aglycosylated Fc fragments which in the absence of disulfide mutations show an unexpected antiparallel arrangement. The glycosylated Knob-Knob Fc fragment is destabilized as indicated by variability in the relative orientation of its CH3 domains. The glycosylated Hole-Hole Fc fragment shows an unexpected intermolecular disulfide bond via the introduced Y349C Hole mutation which results in a large CH3 domain shift and a new CH3-CH3 interface. The crystal structures of glycosylated, disulfide-linked KiH Fc fragment and its Knob-Knob and Hole-Hole side products reported here will facilitate further design of highly efficient antibody heterodimerization strategies. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

RELEASE OF IL-8 AND IL-6 BY BEAS-2B CELLS FOLLOWING IN VITRO EXPOSURE TO BIODIESEL PM EXTRACTS

EPA Science Inventory

Abstract Body: Biodiesel, an alkyl ester of plant oils that can be used in an unmodified diesel engine, is a renewable fuel alternative which show signs of becoming a commercially accepted part of our nation¿s energy infrastructure. Biodiesel exhaust has been physicochemically ch...

40 CFR 1065.260 - Flame-ionization detector.

Code of Federal Regulations, 2012 CFR

2012-07-01

... concentrations on a carbon number basis of one, C1. For measuring THC or THCE you must use a FID analyzer. For... § 1065.205. Note that your FID-based system for measuring THC, THCE, or CH4 must meet all the... bias. (c) Heated FID analyzers. For measuring THC or THCE from compression-ignition engines, two-stroke...

40 CFR 1065.260 - Flame-ionization detector.

Code of Federal Regulations, 2013 CFR

2013-07-01

... concentrations on a carbon number basis of one, C1. For measuring THC or THCE you must use a FID analyzer. For... § 1065.205. Note that your FID-based system for measuring THC, THCE, or CH4 must meet all the... bias. (c) Heated FID analyzers. For measuring THC or THCE from compression-ignition engines, two-stroke...

Characterization of Horizontally-Issuing Reacting Buoyant Jets

DTIC Science & Technology

2011-03-01

125 Appendix B : Unfiltered High Speed Imaging Results ....................................................139 Appendix C: CH* Filtered High...and ( b ) Negative Buoyancy (16) ... 15 Figure 4. (a) Flame and ( b ) Nonflame Combustion in a Spark-Ignition Engine (26) ...... 27 Figure 5. Laminar...a) Fluorescent absorption and emission b ) Emission spectra (30) .................... 41 Figure 9. The X and A Energy States (29

PORE STRUCTURE OF SOOT DEPOSITS FROM SEVERAL COMBUSTION SOURCES. (R825303)

EPA Science Inventory

Abstract

Soot was harvested from five combustion sources: a dodecane flame, marine and bus diesel engines, a wood stove, and an oil furnace. The soots ranged from 20% to 90% carbon by weight and molar C/H ratios from 1 to 7, the latter suggesting a highly condensed aro...

Annual Report on Electronics Research at the University of Texas at Austin.

DTIC Science & Technology

1984-05-15

Beall, E.J. Powers, Roger D. Bengtson and K. Nelin, "Edge Turbulence in TEXT and PRETEXT." Ch.P. Ritz , S.J. Levinson, E.J. Powers, and Roger D...DC 20234 314 Phillips Hall Ithaca, MY 1480 Ori. ay.Harris Office of the Dean Dr. Carlton Walter School of Engineering ElectroScionce Laboratory San

Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

PubMed Central

Owen, D. Des. R.; Shouakar-Stash, O.; Morgenstern, U.; Aravena, R.

2016-01-01

Using a comprehensive data set (dissolved CH4, δ13C-CH4, δ2H-CH4, δ13C-DIC, δ37Cl, δ2H-H2O, δ18O-H2O, Na, K, Ca, Mg, HCO3, Cl, Br, SO4, NO3 and DO), in combination with a novel application of isometric log ratios, this study describes hydrochemical and thermodynamic controls on dissolved CH4 from a coal seam gas reservoir and an alluvial aquifer in the Condamine catchment, eastern Surat/north-western Clarence-Moreton basins, Australia. δ13C-CH4 data in the gas reservoir (−58‰ to −49‰) and shallow coal measures underlying the alluvium (−80‰ to −65‰) are distinct. CO2 reduction is the dominant methanogenic pathway in all aquifers, and it is controlled by SO4 concentrations and competition for reactants such as H2. At isolated, brackish sites in the shallow coal measures and alluvium, highly depleted δ2H-CH4 (<310‰) indicate acetoclastic methanogenesis where SO4 concentrations inhibit CO2 reduction. Evidence of CH4 migration from the deep gas reservoir (200–500 m) to the shallow coal measures (<200 m) or the alluvium was not observed. The study demonstrates the importance of understanding CH4 at different depth profiles within and between aquifers. Further research, including culturing studies of microbial consortia, will improve our understanding of the occurrence of CH4 within and between aquifers in these basins. PMID:27578542

Remote site-selective C-H activation directed by a catalytic bifunctional template

NASA Astrophysics Data System (ADS)

Zhang, Zhipeng; Tanaka, Keita; Yu, Jin-Quan

2017-03-01

In chemical syntheses, the activation of carbon-hydrogen (C-H) bonds converts them directly into carbon-carbon or carbon-heteroatom bonds without requiring any prior functionalization. C-H activation can thus substantially reduce the number of steps involved in a synthesis. A single specific C-H bond in a substrate can be activated by using a ‘directing’ (usually a functional) group to obtain the desired product selectively. The applicability of such a C-H activation reaction can be severely curtailed by the distance of the C-H bond in question from the directing group, and by the shape of the substrate, but several approaches have been developed to overcome these limitations. In one such approach, an understanding of the distal and geometric relationships between the functional groups and C-H bonds of a substrate has been exploited to achieve meta-selective C-H activation by using a covalently attached, U-shaped template. However, stoichiometric installation of this template has not been feasible in the absence of an appropriate functional group on which to attach it. Here we report the design of a catalytic, bifunctional nitrile template that binds a heterocyclic substrate via a reversible coordination instead of a covalent linkage. The two metal centres coordinated to this template have different roles: one reversibly anchors substrates near the catalyst, and the other cleaves remote C-H bonds. Using this strategy, we demonstrate remote, site-selective C-H olefination of heterocyclic substrates that do not have the necessary functional groups for covalently attaching templates.

Remote site-selective C-H activation directed by a catalytic bifunctional template.

PubMed

Zhang, Zhipeng; Tanaka, Keita; Yu, Jin-Quan

2017-03-23

In chemical syntheses, the activation of carbon-hydrogen (C-H) bonds converts them directly into carbon-carbon or carbon-heteroatom bonds without requiring any prior functionalization. C-H activation can thus substantially reduce the number of steps involved in a synthesis. A single specific C-H bond in a substrate can be activated by using a 'directing' (usually a functional) group to obtain the desired product selectively. The applicability of such a C-H activation reaction can be severely curtailed by the distance of the C-H bond in question from the directing group, and by the shape of the substrate, but several approaches have been developed to overcome these limitations. In one such approach, an understanding of the distal and geometric relationships between the functional groups and C-H bonds of a substrate has been exploited to achieve meta-selective C-H activation by using a covalently attached, U-shaped template. However, stoichiometric installation of this template has not been feasible in the absence of an appropriate functional group on which to attach it. Here we report the design of a catalytic, bifunctional nitrile template that binds a heterocyclic substrate via a reversible coordination instead of a covalent linkage. The two metal centres coordinated to this template have different roles: one reversibly anchors substrates near the catalyst, and the other cleaves remote C-H bonds. Using this strategy, we demonstrate remote, site-selective C-H olefination of heterocyclic substrates that do not have the necessary functional groups for covalently attaching templates.

Syntheses, Characterizations, and Applications of Molecular Metal Wires

DTIC Science & Technology

2011-08-05

treated with KPF6 (500 mg, 2.7 mmol). A dark greenish-brown complex was obtained after evaporation. The single crystals suitable for X-ray diffraction...CH2Cl2. Recrystallization from a CH2Cl2 solution layered with hexane gave deep brown single crystals suitable for X-ray diffraction. Yield: 83 mg...5 Synthetic challenges Conductance of single molecules Concluding Remarks

Brain cholinesterase inhibition in songbirds from pecan groves sprayed with phosaline and disulfoton

USGS Publications Warehouse

White, D.H.; Seginak, J.T.

1990-01-01

Disulfoton at 0.83 kg/ha caused moderate to severe brain cholinesterase (ChE) depression in 11 of 15 blue jays collected in pecan groves 6-7 hr after the application. Phosalone at 0.83 kg/ha to pecan groves caused only slight ChE inhibition in a few blue jays and red-bellied woodpeckers.

40 CFR 85.525 - Applicable standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... on FTP test results from the emission data vehicle (EDV) representing the pre-conversion test group. The sum of CO2, CH4, and N2O shall be calculated for pre- and post-conversion FTP test results, where... group. The sum of CO2, CH4, and N2O shall be calculated for pre- and post-conversion FTP test results...

Fabrication and Testing of Electrospun Polyurethane Blended with Chitosan Nanoparticles for Vascular Graft Applications.

PubMed

Subramaniam, Ranjeeta; Mani, Mohan Prasath; Jaganathan, Saravana Kumar

2018-04-26

In this study, a small vascular graft based on polyurethane (PU) blended with chitosan (Ch) nanoparticles was fabricated using electrospinning technique. Initially, the chitosan nanoparticles were synthesized using ionic gelation method. UV-Vis spectrophotometer confirmed the presence of synthesized Ch nanoparticles by exhibiting absorption peak at 288 nm and the Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the existence of the chitosan. Further, the synthesized Ch nanoparticles showed size diameter in the range of 134 ± 58 nm as measured using ImageJ. In the electrospun PU/chitosan graft, the fiber diameter and pore size diameter was found to be reduced compared to the pure PU owing to incorporation of chitosan into PU matrix. The FTIR spectrum revealed the presence of chitosan in the prepared nanocomposite membrane by the formation of the hydrogen bond and peak shift of CH and NH stretching. Moreover, the contact angle measurements revealed that the prepared graft showed decreased contact angle indicating hydrophilic nature compared to the pristine PU. The cytocompatibility studies revealed the non-toxic behavior of the fabricated graft. Hence, the prepared graft exhibiting significant physiochemical and non-toxic properties may be a plausible candidate for cardiovascular graft applications.

Deformed transition-state theory: Deviation from Arrhenius behavior and application to bimolecular hydrogen transfer reaction rates in the tunneling regime.

PubMed

Carvalho-Silva, Valter H; Aquilanti, Vincenzo; de Oliveira, Heibbe C B; Mundim, Kleber C

2017-01-30

A formulation is presented for the application of tools from quantum chemistry and transition-state theory to phenomenologically cover cases where reaction rates deviate from Arrhenius law at low temperatures. A parameter d is introduced to describe the deviation for the systems from reaching the thermodynamic limit and is identified as the linearizing coefficient in the dependence of the inverse activation energy with inverse temperature. Its physical meaning is given and when deviation can be ascribed to quantum mechanical tunneling its value is calculated explicitly. Here, a new derivation is given of the previously established relationship of the parameter d with features of the barrier in the potential energy surface. The proposed variant of transition state theory permits comparison with experiments and tests against alternative formulations. Prescriptions are provided and implemented to three hydrogen transfer reactions: CH 4  + OH → CH 3  + H 2 O, CH 3 Cl + OH → CH 2 Cl + H 2 O and H 2  + CN → H + HCN, widely investigated both experimentally and theoretically. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Elaboration of Copper-Oxygen Mediated C–H Activation Chemistry in Consideration of Future Fuel and Feedstock Generation

PubMed Central

Lee, Jung Yoon; Karlin, Kenneth D

2015-01-01

To contribute solutions for current energy concerns, improvements in the efficiency of C-H bond cleavage chemistry, e.g., selective oxidation of methane to methanol, could minimize losses in natural gas usage or produce feedstocks for fuels. Oxidative C-H activation is also a component of polysaccharide degradation, affording alternative biofuels from abundant biomass. Thus, an understanding of active-site chemistry in copper monooxygenases, those activating strong C-H bonds is briefly reviewed. Then, recent advances in the synthesis-generation and study of various copper-oxygen intermediates are highlighted. Of special interest are cupric-superoxide, Cu-hydroperoxo and Cu-oxy complexes. Such investigations can contribute to an enhanced future application of C-H oxidation or oxygenation processes using air, as concerning societal energy goals. PMID:25756327

Mesenchymal stem cell recruitment by stromal derived factor-1-delivery systems based on chitosan/poly(γ-glutamic acid) polyelectrolyte complexes.

PubMed

Gonçalves, Raquel M; Antunes, Joana C; Barbosa, Mário A

2012-04-10

Human mesenchymal stem cells (hMSCs) have an enormous potential for tissue engineering and cell-based therapies. With a potential of differentiation into multiple lineages and immune-suppression, these cells play a key role in tissue remodelling and regeneration. Here a method of hMSC recruitment is described, based on the incorporation of a chemokine in Chitosan (Ch)/Poly(γ-glutamic acid) (γ-PGA) complexes. Ch is a non-toxic, cationic polysaccharide widely investigated. γ-PGA is a hydrophilic, non-toxic, biodegradable and negatively charged poly-amino acid. Ch and γ-PGA, being oppositely charged, can be combined through electrostatic interactions. These biocompatible structures can be used as carriers for active substances and can be easily modulated in order to control the delivery of drugs, proteins, DNA, etc. Using the layer-by-layer method, Ch and γ-PGA were assembled into polyelectrolyte multilayers films (PEMs) with thickness of 120 nm. The chemokine stromal-derived factor-1 (SDF-1) was incorporated in these complexes and was continuously released during 120 h. The method of SDF-1 incorporation is of crucial importance for polymers assembly into PEMs and for the release kinetics of this chemokine. The Ch/γ-PGA PEMs with SDF-1 were able to recruit hMSCs, increasing the cell migration up to 6 fold to a maximum of 16.2 ± 4.9 cells/mm2. The controlled release of SDF-1 would be of great therapeutic value in the process of hMSC homing to injured tissues. This is the first study suggesting Ch/γ-PGA PEMs as SDF-1 reservoirs to recruit hMSCs, describing an efficient method of chemokine incorporation that allows a sustained released up to 5 days and that can be easily scaled-up.

The Application Of Biofilter System For Reduction Of Methane Emissions From Modern Sanitary Landfills

NASA Astrophysics Data System (ADS)

Sung, K.; Park, S.

2007-12-01

Increased atmospheric concentrations of greenhouse gases (GHG) caused by anthropogenic activities has been related to global climate change. Methane, the second most important GHG after CO2, is 21 times more effective at trapping heat than CO2. Therefore, methane emission control is of utmost importance for global warming reduction. To minimize leachate production and protect groundwater resources, modern sanitary landfills are equipped with composite covers and gas collection systems. Methane from modern sanitary landfills is vented directly to the atmosphere, except for some of the largest landfills where it is recovered as energy and burned at the site. However, the efficiency of energy recovery systems in larger landfills is reduced as the amount of CH4 generated from landfill begins to decrease. In this study, the performance of a lab-scale model biofilter system was investigated to treat CH4 gas emitted from modern sanitary landfills by conducting batch and column experiments using landfill cover soil amended with earthworm cast as the filter bed medium. From the batch experiments to measure the influence of moisture content and temperature of the filter medium on CH4 removal capacity of a biofilter system, the optimum moisture content and temperature were found to be 10-15% by weight and 25-35°C, respectively. The column experiment was conducted to measure the influence of inlet CH4 concentration and CH4 loading rate on CH4 removal capacity of a biofilter system. As the inlet CH4 concentration decreased, the percentage of CH4 oxidized increased. Up to a CH4 loading rate of 2785 g CH4 m3 h- 1 (EBRT = 7.7 min), the CH4 removal efficiency of the biofilter was able to reach 100%. Based on the results of the study, the installation of a properly managed biofilter system should be capable of achieving a reduction in atmospheric CH4 emissions from modern sanitary landfills at low CH4 generation stage.

Estimating methane emissions in California's urban and rural regions using multitower observations

DOE PAGES

Jeong, Seongeun; Newman, Sally; Zhang, Jingsong; ...

2016-11-05

Here, we present an analysis of methane (CH 4) emissions using atmospheric observations from 36 thirteen sites in California during June 2013 – May 2014. A hierarchical Bayesian inversion 37 method is used to estimate CH 4 emissions for spatial regions (0.3° pixels for major regions) by 38 comparing measured CH 4 mixing ratios with transport model (WRF-STILT) predictions based 39 on seasonally varying California-specific CH 4 prior emission models. The transport model is 40 assessed using a combination of meteorological and carbon monoxide (CO) measurements 41 coupled with the gridded California Air Resources Board (CARB) carbon monoxide (CO) 42more » emission inventory. Hierarchical Bayesian inversion suggests that state annual anthropogenic 43 CH 4 emissions are 2.42 ± 0.49 Tg CH 4/yr (at 95% confidence, including transport bias 44 uncertainty), higher (1.2 - 1.8 times) than the CARB current inventory (1.64 Tg CH 4/yr in 2013). 45 We note that the estimated CH 4 emissions drop to 1.0 - 1.6 times the CARB inventory if we 46 correct for the 10% median CH 4 emissions assuming the bias in CO analysis is applicable to 47 CH 4. The CH 4 emissions from the Central Valley and urban regions (San Francisco Bay and 48 South Coast Air Basins) account for ~58% and 26% of the total posterior emissions, 49 respectively. This study suggests that the livestock sector is likely the major contributor to the 50 state total CH 4 emissions, in agreement with CARB’s inventory. Attribution to source sectors for 51 sub-regions of California using additional trace gas species would further improve the 52 quantification of California’s CH 4 emissions and mitigation efforts towards the California Global 53 Warming Solutions Act of 2006 (AB-32).« less

Estimating methane emissions in California's urban and rural regions using multitower observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, Seongeun; Newman, Sally; Zhang, Jingsong

Here, we present an analysis of methane (CH 4) emissions using atmospheric observations from 36 thirteen sites in California during June 2013 – May 2014. A hierarchical Bayesian inversion 37 method is used to estimate CH 4 emissions for spatial regions (0.3° pixels for major regions) by 38 comparing measured CH 4 mixing ratios with transport model (WRF-STILT) predictions based 39 on seasonally varying California-specific CH 4 prior emission models. The transport model is 40 assessed using a combination of meteorological and carbon monoxide (CO) measurements 41 coupled with the gridded California Air Resources Board (CARB) carbon monoxide (CO) 42more » emission inventory. Hierarchical Bayesian inversion suggests that state annual anthropogenic 43 CH 4 emissions are 2.42 ± 0.49 Tg CH 4/yr (at 95% confidence, including transport bias 44 uncertainty), higher (1.2 - 1.8 times) than the CARB current inventory (1.64 Tg CH 4/yr in 2013). 45 We note that the estimated CH 4 emissions drop to 1.0 - 1.6 times the CARB inventory if we 46 correct for the 10% median CH 4 emissions assuming the bias in CO analysis is applicable to 47 CH 4. The CH 4 emissions from the Central Valley and urban regions (San Francisco Bay and 48 South Coast Air Basins) account for ~58% and 26% of the total posterior emissions, 49 respectively. This study suggests that the livestock sector is likely the major contributor to the 50 state total CH 4 emissions, in agreement with CARB’s inventory. Attribution to source sectors for 51 sub-regions of California using additional trace gas species would further improve the 52 quantification of California’s CH 4 emissions and mitigation efforts towards the California Global 53 Warming Solutions Act of 2006 (AB-32).« less

The Iġnik Sikumi Field Experiment, Alaska North Slope: Design, operations, and implications for CO2−CH4 exchange in gas hydrate reservoirs

USGS Publications Warehouse

Boswell, Ray; Schoderbek, David; Collett, Timothy S.; Ohtsuki, Satoshi; White, Mark; Anderson, Brian J.

2017-01-01

The Iġnik Sikumi Gas Hydrate Exchange Field Experiment was conducted by ConocoPhillips in partnership with the U.S. Department of Energy, the Japan Oil, Gas and Metals National Corporation, and the U.S. Geological Survey within the Prudhoe Bay Unit on the Alaska North Slope during 2011 and 2012. The primary goals of the program were to (1) determine the feasibility of gas injection into hydrate-bearing sand reservoirs and (2) observe reservoir response upon subsequent flowback in order to assess the potential for CO2 exchange for CH4 in naturally occurring gas hydrate reservoirs. Initial modeling determined that no feasible means of injection of pure CO2 was likely, given the presence of free water in the reservoir. Laboratory and numerical modeling studies indicated that the injection of a mixture of CO2 and N2 offered the best potential for gas injection and exchange. The test featured the following primary operational phases: (1) injection of a gaseous phase mixture of CO2, N2, and chemical tracers; (2) flowback conducted at downhole pressures above the stability threshold for native CH4 hydrate; and (3) an extended (30-days) flowback at pressures near, and then below, the stability threshold of native CH4 hydrate. The test findings indicate that the formation of a range of mixed-gas hydrates resulted in a net exchange of CO2 for CH4 in the reservoir, although the complexity of the subsurface environment renders the nature, extent, and efficiency of the exchange reaction uncertain. The next steps in the evaluation of exchange technology should feature multiple well applications; however, such field test programs will require extensive preparatory experimental and numerical modeling studies and will likely be a secondary priority to further field testing of production through depressurization. Additional insights gained from the field program include the following: (1) gas hydrate destabilization is self-limiting, dispelling any notion of the potential for uncontrolled destabilization; (2) gas hydrate test wells must be carefully designed to enable rapid remediation of wellbore blockages that will occur during any cessation in operations; (3) sand production during hydrate production likely can be managed through standard engineering controls; and (4) reservoir heat exchange during depressurization was more favorable than expected—mitigating concerns for near-wellbore freezing and enabling consideration of more aggressive pressure reduction.

A novel bioaugmentation strategy to accelerate methanogenesis via adding Geobacter sulfurreducens PCA in anaerobic digestion system.

PubMed

Zhang, Shuo; Chang, Jiali; Liu, Wei; Pan, Yiran; Cui, Kangping; Chen, Xi; Liang, Peng; Zhang, Xiaoyuan; Wu, Qing; Qiu, Yong; Huang, Xia

2018-06-12

Based on the new syntrophic methanogenesis route via direct interspecies electron transfer (DIET), a novel bioaugmentation method by adding exoelectrogenic Geobacter species to accelerate methanogenesis was developed in this study. Geobacter sulfurreducens PCA, type exoelectrogenic strain of Geobacter species was chosen for the research. To clarify the effect of G. sulfurreducens on methanogenesis, batch tests of CH 4 production were carried out. Acetate, the most typical precursor of methanogenesis was chosen as the substrate of batch tests. Amendment of G. sulfurreducens accelerated CH 4 production remarkably. The lag phase of CH 4 production was shortened, and the maximum CH 4 production rate was increased by 78%. Fluorescence in situ hybridization showed that G. sulfurreducens closely gathered with methanogens. For the archaeal communities, the high-throughput sequencing results demonstrated that Methanosaetaceae and Methanobacteriaceae were potential bioaugmented methanogens. We speculated that the accelerated methanogenesis by adding G. sulfurreducens may result from the syntrophic association between G. sulfurreducens and methanogens affiliated with Methanosaetaceae and Methanobacteriaceae. This research provides a new route to enhance methanogenesis through the utilization of G. sulfurreducens. Through this study, the role of Geobacter in the anaerobic engineering and carbon cycling of nature should be paid more attention. Copyright © 2018. Published by Elsevier B.V.

Methane mitigation timelines to inform energy technology evaluation

NASA Astrophysics Data System (ADS)

Roy, Mandira; Edwards, Morgan R.; Trancik, Jessika E.

2015-11-01

Energy technologies emitting differing proportions of methane (CH4) and carbon dioxide (CO2) vary significantly in their relative climate impacts over time, due to the distinct atmospheric lifetimes and radiative efficiencies of the two gases. Standard technology comparisons using the global warming potential (GWP) with a fixed time horizon do not account for the timing of emissions in relation to climate policy goals. Here we develop a portfolio optimization model that incorporates changes in technology impacts based on the temporal proximity of emissions to a radiative forcing (RF) stabilization target. An optimal portfolio, maximizing allowed energy consumption while meeting the RF target, is obtained by year-wise minimization of the marginal RF impact in an intended stabilization year. The optimal portfolio calls for using certain higher-CH4-emitting technologies prior to an optimal switching year, followed by CH4-light technologies as the stabilization year approaches. We apply the model to evaluate transportation technology pairs and find that accounting for dynamic emissions impacts, in place of using the static GWP, can result in CH4 mitigation timelines and technology transitions that allow for significantly greater energy consumption while meeting a climate policy target. The results can inform the forward-looking evaluation of energy technologies by engineers, private investors, and policy makers.

Antibody performance in ChIP-sequencing assays: From quality scores of public data sets to quantitative certification.

PubMed

Mendoza-Parra, Marco-Antonio; Saravaki, Vincent; Cholley, Pierre-Etienne; Blum, Matthias; Billoré, Benjamin; Gronemeyer, Hinrich

2016-01-01

We have established a certification system for antibodies to be used in chromatin immunoprecipitation assays coupled to massive parallel sequencing (ChIP-seq). This certification comprises a standardized ChIP procedure and the attribution of a numerical quality control indicator (QCi) to biological replicate experiments. The QCi computation is based on a universally applicable quality assessment that quantitates the global deviation of randomly sampled subsets of ChIP-seq dataset with the original genome-aligned sequence reads. Comparison with a QCi database for >28,000 ChIP-seq assays were used to attribute quality grades (ranging from 'AAA' to 'DDD') to a given dataset. In the present report we used the numerical QC system to assess the factors influencing the quality of ChIP-seq assays, including the nature of the target, the sequencing depth and the commercial source of the antibody.  We have used this approach specifically to certify mono and polyclonal antibodies obtained from Active Motif directed against the histone modification marks H3K4me3, H3K27ac and H3K9ac for ChIP-seq. The antibodies received the grades AAA to BBC ( www.ngs-qc.org). We propose to attribute such quantitative grading of all antibodies attributed with the label "ChIP-seq grade".

Correlation between CD16a binding and immuno effector functionality of an antigen specific immunoglobulin Fc fragment (Fcab).

PubMed

Kainer, Manuela; Antes, Bernhard; Wiederkum, Susanne; Wozniak-Knopp, Gordana; Bauer, Anton; Rüker, Florian; Woisetschläger, Max

2012-10-15

Antigen binding immunoglobulin Fc fragments (Fcab) are generated by engineering loop regions in the CH3 domain of human IgG1 Fc. Variants of an Fcab specific for Her-2 were designed to display either enhanced (S239D:A330L:I332E) or diminished (L234A:L235A) binding affinities to the Fc receptor CD16a based on mutations described previously. The two mutant Fcab proteins demonstrated the expected modulation of CD16a binding. Interaction with recombinant or cell surface expressed Her-2 was unaffected in both mutants compared to the parental Fcab. Binding affinities for CD16a correlated with the ADCC-potencies of the Fcab variants. Additional studies indicated that the L234A:L235A variant Fcab had equivalent structural features as the unmodified Fcab since their DSC profiles were similar and antigen binding after re-folding upon partial heat denaturation had not changed. Introduction of the S239D:A330L:I332E mutations resulted in a significant reduction of the CH2 domain melting temperature, a moderate decrease of the thermal transition of the CH3 domain and lower antigen binding after thermal stress compared to the parental Fcab. We conclude that the known correlation between CD16a binding affinity and ADCC potency is also valid in Fcab proteins and that antigen specific Fcab molecules can be further engineered for fine tuning of immuno effector functions. Copyright © 2012 Elsevier Inc. All rights reserved.

Exposure of free-flying birds to anticholinesterase insecticides in two conventionally managed fruit orchards

USGS Publications Warehouse

Borges, S.L.

2002-01-01

Conventionally managed orchards receive extensive applications of anticholinesterase (anti-ChE) insecticides throughout the growing season. Because many avian species make use of these environments for nesting and foraging, they may receive substantial exposure to anti-ChEs. The model used to assess avian risk in these environments is highly simplified, and indicator species used in risk studies may misrepresent the risk of the species in the field. A better understanding of avian risk is needed, and should begin with a closer examination o# their exposure in these environments. Exposure of free-flying birds was examined in two conventional orchards during the nesting seasons of 1999 and 2000. Our goal was to demonstrate the influences of species and chemical differences on the exposure we observed. Plasma ChE activity and ChE reactivation were used to identify exposure in multiple species following anti-ChE applications (applied singly and in mixtures). Chipping sparrows (Spizella passerina), American goldfinches (Carduelis tristis), and American robins (Turdus migratorius) demonstrated significant ChE activity depression in 1999 (p 0.005), and only chipping sparrows demonstrated significant depression in 2000 (p = 0.0002). These three species demonstrated the highest proportion of exposed individuals among all species examined in both years. Because many chemicals were simultaneously present in each orchard, chemical influences on the exposure we observed could not be discerned. This work does demonstrate, however, that avian species differ significantly in their exposure, and that chipping sparrows demonstrated the greatest exposure among the species analyzed. These results underscore the need for multiple species studies and for choosing indicator species on a biologically relevant basis.

Effects of organic nitrification inhibitors on methane and nitrous oxide emission from tropical rice paddy

NASA Astrophysics Data System (ADS)

Datta, A.; Adhya, T. K.

2014-08-01

We have studied the effects of application of different nitrification inhibitors on methane (CH4) and nitrous oxide (N2O) emissions from rice paddy and associated soil chemical and biological dynamics during wet and dry seasons of rice crop in a tropical climate of eastern India. The experiment consisted of four treatments viz. (i) Prilled urea amended control (ii) urea + Dicyandiamide (DCD), (iii) urea + Nimin and (iv) urea + Karanjin. CH4 emission was significantly higher from the DCD (372.36 kg ha-1) and Karanjin (153.07 kg ha-1) applied plots during the wet and dry season, respectively. N2O emission was significantly inhibited in the Nimin applied plots during both seasons (69% and 85% over control during wet season and dry season respectively). CH4 and N2O emissions per Mg of rice grain yield were lowest from the Nimin applied plots during both seasons. Global warming potential (GWP) of the plot treated with DCD (13.93) was significantly higher during the experimental period. CH4 production potential was significantly higher from the nitrification inhibitor applied plots compared to control. While, CH4 oxidation potential followed the order; urea + Nimin > urea + Karanjin > urea + DCD > control. Application of Nimin significantly increased the methanotrophic bacterial population in the soil during the maximum tillering to flowering stage and may be attributed to low CH4 emission from the plots. Denitrification enzyme activity (DEA) of the soil was significantly low from the Nimin and Karanjin applied plots. Results suggest that apart from being potent nitrification inhibitors, Nimin and Karanjin also have the potential to reduce the denitrification activity in the soil. This in turn, would reduce N2O emission from flooded paddy where both nitrification and denitrification processes causes N2O emission.

Laboratory Study of Methane Flux from Acid Sulphate Soil in South Kalimantan

NASA Astrophysics Data System (ADS)

Annisa, W.; Cahyana, D.; Syahbuddin, H.; Rachman, A.

2017-06-01

Addition of organic matter in waterlogged conditions will enhance methanogenesis process that produces greenhouse gases. Fresh organic material is considered reactive because it contains carbons that is subject to decompose, therefore, when it exposed to acid sulphate soil, both in natural condition (aeration required) and intensive (aeration not required) will lower the value of redox potential. This experiment aimed to determine the flux of methane (CH4) from various locally available organic materials applied to acid sulphate soil. The experiment was arranged in factorial design with two factors. The first factor was the source of organic matter, i.e. fresh rice straw, fresh purun, fresh cattle manure, composted rice straw, composted purun and composted cattle manure, and control. The second factor was the management of organic matter i.e. placed on the soil surface with no tillage and mixed with soil during tillage. The results showed that application of fresh organic matter into inundated acid sulphate soil increased CH4 fluxes up to 23.78 µg CH4 g1 d1 which was higher than from composted organic matter (4.327 µg CH4.g1.d1). Methane flux due to organic matter management was significantly negatively (p=0.001) correlated with soil redox potential (Eh) with R2 of - 0.76. Organic matter placed on the soil surface with no tillage produced methane flux ranged from 0.33 to 20.78 g CH4 g1 d1, which was lower than methane flux produced from organic matter mixed with soil during tillage (0.38 to 27.27 g CH4 g1 d1). Composting organic matter before application and mixing them with the soil through tillage are highly recommended to reduce greenhouse gas emissions from cultivated acid sulphate soils.

First records of a field experiment on fertilizer effects on methane emission from rice fields in Hunan-Province (PR China)

NASA Astrophysics Data System (ADS)

Wassmann, R.; Wang, M. X.; Shangguan, X. J.; Xie, X. L.; Shen, R. X.; Wang, Y. S.; Papen, H.; Rennenberg, H.; Seiler, W.

Fertilizer effects on methane emission from Chinese rice fields were investigated by a praxis-oriented approach applying balanced amendments of N, P and K. The data set obtained covered the emission rates of app. one month in early rice and one month in late rice 1991. An intercomparison between the 4 treatments showed pronounced differences in the magnitudes of methane emission rates. The combined organic/mineral fertilizer application, commonly used as local farming practice, resulted in relatively high seasonal averages of methane emission rates (26.5 mg CH4 m-2 h-1 in early rice and 50.1 mg CH4 m-2 h-1 in late rice). The lowest emission rates were observed in the plot with pure mineral fertilization (6.5 mg CH4 m-2 h-1 in early rice and 14.3 mg CH4 m-2 h-1 in late rice). Pure organic fertilizers by unfermented substances yielded the highest methane emission rates of all field trials (38.6 mg CH4 m-2 h-1 in early rice and 56.2 CH4 m-2 h-1 in late rice). The fertilization with fermented material derived from biogas generators resulted in substantially lower emission rates than the other trials with organic amendments, the seasonal averages corresponded to 15.9 mg CH4 m-2 h-1 (early rice) and 22.5 mg CH4 m-2 h-1 (late rice). Interpretation of the results can be obtained from the different potentials of these fertilizers for methane production. Based on this concept the different methane emission rates observed with organic/mineral, pure mineral and pure unfermented-organic fertilizers could directly be attributed to the different quantities of organic matter incorporated into the soil. The low methane emission from the plot treated with fermented material could be explained by a depletion of potential methane precursors resulting from the preceding fermentation. The results of this investigation provide evidence that the extensive use of specific chemical fertilizers and the application of sludge from the operation of biogas generators could lead to a net reduction of the methane emission from rice fields.

Estimating global natural wetland methane emissions using process modelling: spatio-temporal patterns and contributions to atmospheric methane fluctuations

USGS Publications Warehouse

Zhu, Qiuan; Peng, Changhui; Chen, Huai; Fang, Xiuqin; Liu, Jinxun; Jiang, Hong; Yang, Yanzheng; Yang, Gang

2015-01-01

Aim The fluctuations of atmospheric methane (CH4) that have occurred in recent decades are not fully understood, particularly with regard to the contribution from wetlands. The application of spatially explicit parameters has been suggested as an effective method for reducing uncertainties in bottom-up approaches to wetland CH4 emissions, but has not been included in recent studies. Our goal was to estimate spatio-temporal patterns of global wetland CH4 emissions using a process model and then to identify the contribution of wetland emissions to atmospheric CH4fluctuations. Location Global. Methods A process-based model integrated with full descriptions of methanogenesis (TRIPLEX-GHG) was used to simulate global wetland CH4emissions. Results Global annual wetland CH4 emissions ranged from 209 to 245 Tg CH4 year−1 between 1901 and 2012, with peaks occurring in 1991 and 2012. There is a decreasing trend between 1990 and 2010 with a rate of approximately 0.48 Tg CH4 year−1, which was largely caused by emissions from tropical wetlands showing a decreasing trend of 0.44 Tg CH4 year−1 since the 1970s. Emissions from tropical, temperate and high-latitude wetlands comprised 59, 26 and 15% of global emissions, respectively. Main conclusion Global wetland CH4 emissions, the interannual variability of which was primary controlled by tropical wetlands, partially drive the atmosphericCH4 burden. The stable to decreasing trend in wetland CH4 emissions, a result of a balance of emissions from tropical and extratropical wetlands, was a particular factor in slowing the atmospheric CH4 growth rate during the 1990s. The rapid decrease in tropical wetland CH4emissions that began in 2000 was supposed to offset the increase in anthropogenic emissions and resulted in a relatively stable level of atmospheric CH4 from 2000 to 2006. Increasing wetland CH4 emissions, particularly after 2010, should be an important contributor to the growth in atmospheric CH4 seen since 2007.

Simultaneous identification of multi-combustion-intermediates of alkanol-air flames by femtosecond filament excitation for combustion sensing

PubMed Central

Li, Helong; Chu, Wei; Xu, Huailiang; Cheng, Ya; Chin, See-Leang; Yamanouchi, Kaoru; Sun, Hong-Bo

2016-01-01

Laser filamentation produced by the propagation of intense laser pulses in flames is opening up new possibility in application to combustion diagnostics that can provide useful information on understanding combustion processes, enhancing combustion efficiency and reducing pollutant products. Here we present simultaneous identification of multiple combustion intermediates by femtosecond filament excitation for five alkanol-air flames fueled by methanol, ethanol, n-propanol, n-butanol, and n-pentanol. We experimentally demonstrate that the intensities of filament-induced photoemission signals from the combustion intermediates C, C2, CH, CN increase with the increasing number of carbons in the fuel molecules, and the signal ratios between the intermediates (CH/C, CH/C2, CN/C, CH/C2, CN/CH) are different for different alkanol combustion flames. Our observation provides a way for sensing multiple combustion components by femtosecond filament excitation in various combustion conditions that strongly depend on the fuel species. PMID:27250021

The use of nanoencapsulation to decrease human skin irritation caused by capsaicinoids

PubMed Central

Contri, Renata V; Frank, Luiza A; Kaiser, Moacir; Pohlmann, Adriana R; Guterres, Silvia S

2014-01-01

Capsaicin, a topical analgesic used in the treatment of chronic pain, has irritant properties that frequently interrupt its use. In this work, the effect of nanoencapsulation of the main capsaicinoids (capsaicin and dihydrocapsaicin) on skin irritation was tested in humans. Skin tolerance of a novel vehicle composed of chitosan hydrogel containing nonloaded nanocapsules (CH-NC) was also evaluated. The chitosan hydrogel containing nanoencapsulated capsaicinoids (CH-NC-CP) did not cause skin irritation, as measured by an erythema probe and on a visual scale, while a formulation containing free capsaicinoids (chitosan gel with hydroalcoholic solution [CH-ET-CP]) and a commercially available capsaicinoids formulation caused skin irritation. Thirty-one percent of volunteers reported slight irritation one hour after application of CH-NC-CP, while moderate (46% [CH-ET-CP] and 23% [commercial product]) and severe (8% [CH-ET-CP] and 69% [commercial product]) irritation were described for the formulations containing free capsaicinoids. When CH-NC was applied to the skin, erythema was not observed and only 8% of volunteers felt slight irritation, which demonstrates the utility of the novel vehicle. A complementary in vitro skin permeation study showed that permeation of capsaicinoids through an epidermal human membrane was reduced but not prevented by nanoencapsulation. PMID:24611011

ChIP-PaM: an algorithm to identify protein-DNA interaction using ChIP-Seq data.

PubMed

Wu, Song; Wang, Jianmin; Zhao, Wei; Pounds, Stanley; Cheng, Cheng

2010-06-03

ChIP-Seq is a powerful tool for identifying the interaction between genomic regulators and their bound DNAs, especially for locating transcription factor binding sites. However, high cost and high rate of false discovery of transcription factor binding sites identified from ChIP-Seq data significantly limit its application. Here we report a new algorithm, ChIP-PaM, for identifying transcription factor target regions in ChIP-Seq datasets. This algorithm makes full use of a protein-DNA binding pattern by capitalizing on three lines of evidence: 1) the tag count modelling at the peak position, 2) pattern matching of a specific tag count distribution, and 3) motif searching along the genome. A novel data-based two-step eFDR procedure is proposed to integrate the three lines of evidence to determine significantly enriched regions. Our algorithm requires no technical controls and efficiently discriminates falsely enriched regions from regions enriched by true transcription factor (TF) binding on the basis of ChIP-Seq data only. An analysis of real genomic data is presented to demonstrate our method. In a comparison with other existing methods, we found that our algorithm provides more accurate binding site discovery while maintaining comparable statistical power.

Mercury speciation with fluorescent gold nanocluster as a probe.

PubMed

Yang, Jian-Yu; Yang, Ting; Wang, Xiao-Yan; Chen, Ming-Li; Yu, Yong-Liang; Wang, Jian-Hua

2018-05-11

Fluorescent nanoparticles are widely used for sensing biologically significant species. However, it is rarely reported for the discrimination or speciation of metal species. In this work, we report for the first time the speciation of mercury (Hg 2+ ) and methylmercury (CH 3 Hg + ) by taking advantage of the fluorescence feature of folic acid-capped gold nanoclusters (FA-AuNCs). FA-Au NCs exhibit an average size of 2.08±0.15 nm and a maximum emission at λ ex /λ em = 280/440 nm with a quantum yield of 27.3%. It is interesting that Hg 2+ causes a significant quench on the fluorescence of FA-Au NCs, whereas CH 3 Hg + leads to a remarkable fluorescence enhancement. Based on this discriminative fluorescent response between Hg 2+ and CH 3 Hg + , a novel nanosensor for the speciation of CH 3 Hg + and Hg 2+ was developed, providing limits of detection (LOD) of 28 nM for Hg 2+ and 25 nM for CH 3 Hg + within 100-1000 nM. This sensing system is highly selective to mercury. Its practical applications were further demonstrated by the analysis of CH 3 Hg + and the speciation of mercury (CH 3 Hg + and Hg 2+ ) in environmental water and fish samples.

Effects of Tillage and Nitrogen Fertilizers on CH4 and CO2 Emissions and Soil Organic Carbon in Paddy Fields of Central China

PubMed Central

Zhi-Kui, Kou; Zhi-Sheng, Zhang; Jin-Ping, Wang; Ming-Li, Cai; Cou-Gui, Cao

2012-01-01

Quantifying carbon (C) sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT) and no-tillage (NT)] and the application of nitrogen (N) fertilizer (0 and 210 kg N ha−1) on fluxes of CH4 and CO2, and soil organic C (SOC) sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH4 emissions by 13%–66% and SOC by 21%–94% irrespective of soil sampling depths, but had no effect on CO2 emissions in either year. Tillage significantly affected CH4 and CO2 emissions, where NT significantly decreased CH4 emissions by 10%–36% but increased CO2 emissions by 22%–40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%–48% in the 0–5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0–20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered. PMID:22574109

Laser-absorption sensing of gas composition of products from coal gasification

NASA Astrophysics Data System (ADS)

Jeffries, Jay B.; Sur, Ritobrata; Sun, Kai; Hanson, Ronald K.

2014-06-01

A prototype in-situ laser-absorption sensor for the real-time composition measurement (CO, CH4, H2O and CO2) of synthesis gas products of coal gasification (called here syngas) was designed, tested in the laboratory, and demonstrated during field-measurement campaigns in a pilot-scale entrained flow gasifier at the University of Utah and in an engineering-scale, fluidized-bed transport gasifier at the National Carbon Capture Center (NCCC). The prototype design and operation were improved by the lessons learned from each field test. Laser-absorption measurements are problematic in syngas flows because efficient gasifiers operate at elevated pressures (10-50 atm) where absorption transitions are collision broadened and absorption transitions that are isolated at 1 atm become blended into complex features, and because syngas product streams can contain significant particulate, producing significant non-absorption scattering losses of the transmission of laser light. Thus, the prototype sensor used a new wavelength-scanned, wavelength-modulation spectroscopy strategy with 2f-detection and 1f-normalization (WMS-2f/1f) that can provide sensitive absorption measurements of species with spectra blended by collision broadening even in the presence of large non-absorption laser transmission losses (e.g., particulate scattering, beam steering, etc.). The design of the sensor for detection of CO, CH4, H2O and CO2 was optimized for the specific application of syngas monitoring at the output of large-scale gasifiers. Sensor strategies, results and lessons learned from these field measurement campaigns are discussed.

Total cross sections of electron scattering by molecules NF3, PF3, N(CH3)3, P(CH3)3, NH(CH3)2, PH(CH3)2, NH2CH3 and PH2CH3 at 30-5000 eV

NASA Astrophysics Data System (ADS)

Shi, D. H.; Sun, J. F.; Zhu, Z. L.; Liu, Y. F.

2010-04-01

Total cross sections of electron scattering by eight molecules NF3, PF3, N(CH3)3, P(CH3)3, NH(CH3)2, PH(CH3)2, NH2CH3 and PH2CH3, which have some structural similarities, are calculated at the Hartree-Fork level by the modified additivity rule approach [D.H. Shi, J.F. Sun, Z.L. Zhu, H. Ma, Y.F. Liu, Eur. Phys. J. D 45, 253 (2007); D.H. Shi, J.F. Sun, Y.F. Liu, Z.L. Zhu, X.D. Yang, Chin. Opt. Lett. 4, 192 (2006)]. The modified additivity rule approach takes into considerations that the contributions of the geometric shielding effect vary as the energy of incident electrons, the dimension of target molecule, the number of electrons in the molecule and the number of atoms constituting the molecule. The present investigations cover the impact energy range from 30 to 5000 eV. The quantitative total cross sections are compared with those obtained by experiments and other theories. Excellent agreement is observed even at energies of several tens of eV. It shows that the modified additivity rule approach is applicable to carry out the total cross section calculations of electron scattering by these molecules at intermediate and high energies, in particular over the energy range above 80 eV or so. It proves that the microscopic molecular properties, such as the geometrical size of the target and the number of atoms constituting the molecule, are of crucial importance in the TCS calculations. The new results for PH(CH3)2 and PH2CH3 are also presented at energies from 30 to 5000 eV, although no experimental and theoretical data are available for comparison. In the present calculations, the atoms are still represented by the spherical complex optical potential, which is composed of static, exchange, polarization and absorption terms.

Methane emissions from floodplains in the Amazon Basin: challenges in developing a process-based model for global applications

NASA Astrophysics Data System (ADS)

Ringeval, B.; Houweling, S.; van Bodegom, P. M.; Spahni, R.; van Beek, R.; Joos, F.; Röckmann, T.

2014-03-01

Tropical wetlands are estimated to represent about 50% of the natural wetland methane (CH4) emissions and explain a large fraction of the observed CH4 variability on timescales ranging from glacial-interglacial cycles to the currently observed year-to-year variability. Despite their importance, however, tropical wetlands are poorly represented in global models aiming to predict global CH4 emissions. This publication documents a first step in the development of a process-based model of CH4 emissions from tropical floodplains for global applications. For this purpose, the LPX-Bern Dynamic Global Vegetation Model (LPX hereafter) was slightly modified to represent floodplain hydrology, vegetation and associated CH4 emissions. The extent of tropical floodplains was prescribed using output from the spatially explicit hydrology model PCR-GLOBWB. We introduced new plant functional types (PFTs) that explicitly represent floodplain vegetation. The PFT parameterizations were evaluated against available remote-sensing data sets (GLC2000 land cover and MODIS Net Primary Productivity). Simulated CH4 flux densities were evaluated against field observations and regional flux inventories. Simulated CH4 emissions at Amazon Basin scale were compared to model simulations performed in the WETCHIMP intercomparison project. We found that LPX reproduces the average magnitude of observed net CH4 flux densities for the Amazon Basin. However, the model does not reproduce the variability between sites or between years within a site. Unfortunately, site information is too limited to attest or disprove some model features. At the Amazon Basin scale, our results underline the large uncertainty in the magnitude of wetland CH4 emissions. Sensitivity analyses gave insights into the main drivers of floodplain CH4 emission and their associated uncertainties. In particular, uncertainties in floodplain extent (i.e., difference between GLC2000 and PCR-GLOBWB output) modulate the simulated emissions by a factor of about 2. Our best estimates, using PCR-GLOBWB in combination with GLC2000, lead to simulated Amazon-integrated emissions of 44.4 ± 4.8 Tg yr-1. Additionally, the LPX emissions are highly sensitive to vegetation distribution. Two simulations with the same mean PFT cover, but different spatial distributions of grasslands within the basin, modulated emissions by about 20%. Correcting the LPX-simulated NPP using MODIS reduces the Amazon emissions by 11.3%. Finally, due to an intrinsic limitation of LPX to account for seasonality in floodplain extent, the model failed to reproduce the full dynamics in CH4 emissions but we proposed solutions to this issue. The interannual variability (IAV) of the emissions increases by 90% if the IAV in floodplain extent is accounted for, but still remains lower than in most of the WETCHIMP models. While our model includes more mechanisms specific to tropical floodplains, we were unable to reduce the uncertainty in the magnitude of wetland CH4 emissions of the Amazon Basin. Our results helped identify and prioritize directions towards more accurate estimates of tropical CH4 emissions, and they stress the need for more research to constrain floodplain CH4 emissions and their temporal variability, even before including other fundamental mechanisms such as floating macrophytes or lateral water fluxes.

A microbial functional group-based module for simulating methane production and consumption: Application to an incubated permafrost soil

DOE PAGES

Xu, Xiaofeng; Elias, Dwayne A.; Graham, David E.; ...

2015-07-23

In this study, accurately estimating methane (CH 4) flux is critically important for investigating and predicting the biogeochemistry-climate feedback. Better simulating CH 4 flux requires explicit representations of microbial processes on CH 4 dynamics because all processes for CH 4 production and consumption are actually carried out by microbes. A microbial functional group based module was developed and tested against an incubation experiment. The module considers four key mechanisms for CH 4 production and consumption: methanogenesis from acetate or single-carbon compounds and CH 4 oxidation using molecular oxygen or other inorganic electron acceptors. These four processes were carried out bymore » four microbial functional groups: acetoclastic methanogens, hydrogenotrophic methanogens, aerobic methanotrophs, and anaerobic methanotrophs. This module was then linked with the decomposition subroutine of the Community Land Model, and was further used to simulate dynamics of carbon dioxide (CO 2) and CH 4 concentrations from an incubation experiment with permafrost soils. The results show that the model could capture the dynamics of CO 2 and CH 4 concentrations in microcosms with top soils, mineral layer soils and permafrost soils under natural and saturated moisture conditions and a temperature gradient of -2°C, 3°C, and 5°C. Sensitivity analysis confirmed the importance of acetic acid's direct contribution as substrate and indirect effects through pH feedback on CO 2 and CH 4 production and consumption. This study suggests that representing the microbial mechanisms is critical for modeling CH 4 production and consumption; it is urgent to incorporate microbial mechanisms into Earth system models for better predicting the behavior of the climate system.« less

Optical properties of highly compressed polystyrene: An ab initio study

DOE PAGES

Hu, S. X.; Collins, L. A.; Colgan, J. P.; ...

2017-10-16

Using all-electron density functional theory, we have performed an ab initio study on x ray absorption spectra of highly compressed polystyrene (CH). Here, we found that the K-edge shifts in strongly coupled, degenerate polystyrene cannot be explained by existing continuum-lowering models adopted in traditional plasma physics. To gain insights into the K edge shift in warm, dense CH, we have developed a model designated as “single-mixture-in-a-box” (SMIAB), which incorporates both the lowering of continuum and the rising of Fermi surface resulting from high compression. This simple SMIAB model correctly predicts the K-edge shift of carbon in highly compressed CH inmore » good agreement with results from quantum-molecular-dynamics (QMD) calculations. Traditional opacity models failed to give the proper K-edge shifts as the CH density increased. Based on QMD calculations, we have established a first-principles opacity table (FPOT) for CH in a wide range of densities and temperatures [p = 0.1 to 100 g/cm 3 and T = 2000 to 1,000,000 K]. The FPOT gives much higher Rosseland mean opacity compared to the cold-opacity–patched astrophysics opacity table for warm, dense CH and favorably compares to the newly improved Los Alamos ATOMIC model for moderately compressed CH (pCH ≤10 g/cm 3) but remains a factor of 2 to 3 higher at extremely high densities (pCH ≥ 50 g/cm 3). We anticipate the established FPOT of CH will find important applications to reliable designs of high-energy-density experiments. Moreover, the understanding of K-edge shifting revealed in this study could provide guides for improving the traditional opacity models to properly handle the strongly coupled and degenerate conditions.« less

A flux-gradient system for simultaneous measurement of the CH4, CO2, and H2O fluxes at a lake-air interface.

PubMed

Xiao, Wei; Liu, Shoudong; Li, Hanchao; Xiao, Qitao; Wang, Wei; Hu, Zhenghua; Hu, Cheng; Gao, Yunqiu; Shen, Jing; Zhao, Xiaoyan; Zhang, Mi; Lee, Xuhui

2014-12-16

Inland lakes play important roles in water and greenhouse gas cycling in the environment. This study aims to test the performance of a flux-gradient system for simultaneous measurement of the fluxes of water vapor, CO2, and CH4 at a lake-air interface. The concentration gradients over the water surface were measured with an analyzer based on the wavelength-scanned cavity ring-down spectroscopy technology, and the eddy diffusivity was measured with a sonic anemometer. Results of a zero-gradient test indicate a flux measurement precision of 4.8 W m(-2) for water vapor, 0.010 mg m(-2) s(-1) for CO2, and 0.029 μg m(-2) s(-1) for CH4. During the 620 day measurement period, 97%, 69%, and 67% of H2O, CO2, and CH4 hourly fluxes were higher in magnitude than the measurement precision, which confirms that the flux-gradient system had adequate precision for the measurement of the lake-air exchanges. This study illustrates four strengths of the flux-gradient method: (1) the ability to simultaneously measure the flux of H2O, CO2, and CH4; (2) negligibly small density corrections; (3) the ability to resolve small CH4 gradient and flux; and (4) continuous and noninvasive operation. The annual mean CH4 flux (1.8 g CH4 m(-2) year(-1)) at this hypereutrophic lake was close to the median value for inland lakes in the world (1.6 g CH4 m(-2) year(-1)). The system has adequate precision for CH4 flux for broad applications but requires further improvement to resolve small CO2 flux in many lakes.

Optical properties of highly compressed polystyrene: An ab initio study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, S. X.; Collins, L. A.; Colgan, J. P.

Using all-electron density functional theory, we have performed an ab initio study on x ray absorption spectra of highly compressed polystyrene (CH). Here, we found that the K-edge shifts in strongly coupled, degenerate polystyrene cannot be explained by existing continuum-lowering models adopted in traditional plasma physics. To gain insights into the K edge shift in warm, dense CH, we have developed a model designated as “single-mixture-in-a-box” (SMIAB), which incorporates both the lowering of continuum and the rising of Fermi surface resulting from high compression. This simple SMIAB model correctly predicts the K-edge shift of carbon in highly compressed CH inmore » good agreement with results from quantum-molecular-dynamics (QMD) calculations. Traditional opacity models failed to give the proper K-edge shifts as the CH density increased. Based on QMD calculations, we have established a first-principles opacity table (FPOT) for CH in a wide range of densities and temperatures [p = 0.1 to 100 g/cm 3 and T = 2000 to 1,000,000 K]. The FPOT gives much higher Rosseland mean opacity compared to the cold-opacity–patched astrophysics opacity table for warm, dense CH and favorably compares to the newly improved Los Alamos ATOMIC model for moderately compressed CH (pCH ≤10 g/cm 3) but remains a factor of 2 to 3 higher at extremely high densities (pCH ≥ 50 g/cm 3). We anticipate the established FPOT of CH will find important applications to reliable designs of high-energy-density experiments. Moreover, the understanding of K-edge shifting revealed in this study could provide guides for improving the traditional opacity models to properly handle the strongly coupled and degenerate conditions.« less

From Numerical Problem Solving to Model-Based Experimentation Incorporating Computer-Based Tools of Various Scales into the ChE Curriculum

ERIC Educational Resources Information Center

Shacham, Mordechai; Cutlip, Michael B.; Brauner, Neima

2009-01-01

A continuing challenge to the undergraduate chemical engineering curriculum is the time-effective incorporation and use of computer-based tools throughout the educational program. Computing skills in academia and industry require some proficiency in programming and effective use of software packages for solving 1) single-model, single-algorithm…

Draft Genome Sequence of Methylomicrobium buryatense Strain 5G, a Haloalkaline-Tolerant Methanotrophic Bacterium

PubMed Central

Khmelenina, Valentina N.; Beck, David A. C.; Munk, Christine; Davenport, Karen; Daligault, Hajnalka; Erkkila, Tracy; Goodwin, Lynne; Gu, Wei; Lo, Chien-Chi; Scholz, Matthew; Teshima, Hazuki; Xu, Yan; Chain, Patrick; Bringel, Francoise; Vuilleumier, Stéphane; DiSpirito, Alan; Dunfield, Peter; Jetten, Mike S. M.; Klotz, Martin G.; Knief, Claudia; Murrell, J. Colin; Op den Camp, Huub J. M.; Sakai, Yasuyoshi; Semrau, Jeremy; Svenning, Mette; Stein, Lisa Y.; Trotsenko, Yuri A.

2013-01-01

Robust growth of the gammaproteobacterium Methylomicrobium buryatense strain 5G on methane makes it an attractive system for CH4-based biocatalysis. Here we present a draft genome sequence of the strain that will provide a valuable framework for metabolic engineering of the core pathways for the production of valuable chemicals from methane. PMID:23814105

REECo activities and sample logistics in support of the Nevada Applied Ecology Group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wireman, D.L.; Rosenberry, C.E. Jr.; White, M.G.

Activities and sample logistics of Reynolds Electrical and Engineering Co., Inc. (REECo), in support of the Nevada Applied Ecology Group (NAEG), are discussed in this summary report. Activities include the collection, preparation, and shipment of samples of soils, vegetation, and small animals collected at Pu-contaminated areas of the Nevada Test Site and Tonopah Test Range. (CH)

Towards Sustainable C-H Functionalization Reactions: The Emerging Role of Bio-Based Reaction Media.

PubMed

Santoro, Stefano; Marrocchi, Assunta; Lanari, Daniela; Ackermann, Lutz; Vaccaro, Luigi

2018-04-18

In the last decade, transition-metal catalyzed C-H functionalization reactions have progressed enourmosly, becoming a useful tool in organic synthesis and a practibable alternative to well-established methodologies. Very recently, research efforts have also been devoted to developing more sustainable C-H functionalization protocols, in order to increase their applicability. One of the most promising approaches in this sense is represented by the substitution of common reaction media with bio-based solvents. In the present contribution a general perspective on the benefits of this approach is given, followed by selected literature examples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Research Update: Emerging chalcostibite absorbers for thin-film solar cells

DOE PAGES

de Souza Lucas, Francisco Willian; Zakutayev, Andriy

2018-06-04

Copper antimony chalcogenides CuSbCh 2 (Ch=S, Se) are an emerging family of absorbers studied for thin-film solar cells. These non-toxic and Earth-abundant materials show a layered low-dimensional chalcostibite crystal structure, leading to interesting optoelectronic properties for applications in photovoltaic (PV) devices. This research update describes the CuSbCh 2 crystallographic structures, synthesis methods, competing phases, band structures, optoelectronic properties, point defects, carrier dynamics, and interface band offsets, based on experimental and theoretical data. Correlations between these absorber properties and PV device performance are discussed, and opportunities for further increase in the efficiency of the chalcostibite PV devices are highlighted.

Research Update: Emerging chalcostibite absorbers for thin-film solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Souza Lucas, Francisco Willian; Zakutayev, Andriy

Copper antimony chalcogenides CuSbCh 2 (Ch=S, Se) are an emerging family of absorbers studied for thin-film solar cells. These non-toxic and Earth-abundant materials show a layered low-dimensional chalcostibite crystal structure, leading to interesting optoelectronic properties for applications in photovoltaic (PV) devices. This research update describes the CuSbCh 2 crystallographic structures, synthesis methods, competing phases, band structures, optoelectronic properties, point defects, carrier dynamics, and interface band offsets, based on experimental and theoretical data. Correlations between these absorber properties and PV device performance are discussed, and opportunities for further increase in the efficiency of the chalcostibite PV devices are highlighted.

Cholinesterase inhibition of birds inhabiting wheat fields treated with methyl parathion and toxaphene

USGS Publications Warehouse

Niethammer, K.R.; Baskett, T.S.

1983-01-01

Red-winged blackbirds (Agelaius phoeniceus) and dickcissels (Spiza americana) inhabiting wheat fields treated with 0.67 kg AI/ha methyl parathion and 1.35 kg AI/ha toxaphene showed brain cholinesterase (ChE) inhibition compared with birds inhabiting untreated fields. Maximum inhibition occurred about five days after insecticide application. ChE activities again approached normal 10 days after treatment. ChE inhibition for dickcissels and red-winged blackbirds differed significantly (p<0.05); maximum inhibition for the former species was 74%, and for the latter, 40%. These differences could not be explained by the diets of the two species, as they were similar.

Comparison of atmospheric CH4 concentration observed by GOSAT and in-situ measurements in Thailand and India

NASA Astrophysics Data System (ADS)

Hayashida, S.; Ono, A.; Ishikawa, S.; Terao, Y.; Takeuchi, W.

2012-12-01

The concentration of atmospheric methane (CH4) has more than doubled since pre-industrial levels and the observed long-term changes in the CH4 concentration have been attributed to anthropogenic activity. However, despite the importance of atmospheric CH4 in global warming, the strength of individual sources of CH4 remains highly uncertain [e.g.,Dlugokencky et al., 2011]. To characterize and quantify the emissions of CH4 especially in Monsoon Asia and Siberia, which are the most important regions as CH4 source, we started a new project, "Characterization and Quantification of global methane emissions by utilizing GOSAT and in-situ measurements " by support of the Environment Research and Technology Development Fund (ERTDF) from June 2012 under the umbrella of Ministry of Environment Japan. The projects includes (1) satellite data applications, (2) in-situ measurements in Siberia, over Western Pacific and in Monsoon Asia, (3) development of the inverse model to derive CH4 emissions by top-down approach, and (4) flux measurements in Siberia and Asia to improve the bottom-up inventories. As an initiatory approach in the project, we started air sampling in Thailand and India where there are only a few CH4 data of direct sampling with high precision. We took eight air samples at Kohn Kaen and Pimai in Thailand on June 9 and 10, 2012. The high CH4 concentration near rice paddy field contrasted to the lower CH4 concentration near Cassava field. We are planning to take more samples in India in mid-August. The satellite CH4 data including GOSAT and SCIAMACHY are also compared with the Land Surface Water Coverage (LSWC) and the Normalized Difference Vegetation Index (NDVI). The analysis revealed the seasonal variation in of xCH4 is closely related to the variation of the LSWC, coupled with NDVI. However, the satellite measurements are all column-averaged mixing ratio (xCH4), and therefore do not necessarily reflect high CH4 concentration near the surface over the emission regions. To optimize "inverse approach", we need to investigate the relation between xCH4 and the surface concentration, and need to combine it to the bottom-up approach. We will also discuss representativeness of GOSAT measurement from the viewpoint of spatial and time scale when it observes such heterogeneous emission regions.

Regional landfills methane emission inventory in Malaysia.

PubMed

Abushammala, Mohammed F M; Noor Ezlin Ahmad Basri; Basri, Hassan; Ahmed Hussein El-Shafie; Kadhum, Abdul Amir H

2011-08-01

The decomposition of municipal solid waste (MSW) in landfills under anaerobic conditions produces landfill gas (LFG) containing approximately 50-60% methane (CH(4)) and 30-40% carbon dioxide (CO(2)) by volume. CH(4) has a global warming potential 21 times greater than CO(2); thus, it poses a serious environmental problem. As landfills are the main method for waste disposal in Malaysia, the major aim of this study was to estimate the total CH(4) emissions from landfills in all Malaysian regions and states for the year 2009 using the IPCC, 1996 first-order decay (FOD) model focusing on clean development mechanism (CDM) project applications to initiate emission reductions. Furthermore, the authors attempted to assess, in quantitative terms, the amount of CH(4) that would be emitted from landfills in the period from 1981-2024 using the IPCC 2006 FOD model. The total CH(4) emission using the IPCC 1996 model was estimated to be 318.8 Gg in 2009. The Northern region had the highest CH(4) emission inventory, with 128.8 Gg, whereas the Borneo region had the lowest, with 24.2 Gg. It was estimated that Pulau Penang state produced the highest CH(4) emission, 77.6 Gg, followed by the remaining states with emission values ranging from 38.5 to 1.5 Gg. Based on the IPCC 1996 FOD model, the total Malaysian CH( 4) emission was forecast to be 397.7 Gg by 2020. The IPCC 2006 FOD model estimated a 201 Gg CH(4) emission in 2009, and estimates ranged from 98 Gg in 1981 to 263 Gg in 2024.

The role of CH/π interactions in the high affinity binding of streptavidin and biotin.

PubMed

Ozawa, Motoyasu; Ozawa, Tomonaga; Nishio, Motohiro; Ueda, Kazuyoshi

2017-08-01

The streptavidin-biotin complex has an extraordinarily high affinity (Ka: 10 15 mol -1 ) and contains one of the strongest non-covalent interactions known. This strong interaction is widely used in biological tools, including for affinity tags, detection, and immobilization of proteins. Although hydrogen bond networks and hydrophobic interactions have been proposed to explain this high affinity, the reasons for it remain poorly understood. Inspired by the deceased affinity of biotin observed for point mutations of streptavidin at tryptophan residues, we hypothesized that a CH/π interaction may also contribute to the strong interaction between streptavidin and biotin. CH/π interactions were explored and analyzed at the biotin-binding site and at the interface of the subunits by the fragment molecular orbital method (FMO) and extended applications: PIEDA and FMO4. The results show that CH/π interactions are involved in the high affinity for biotin at the binding site of streptavidin. We further suggest that the involvement of CH/π interactions at the subunit interfaces and an extended CH/π network play more critical roles in determining the high affinity, rather than involvement at the binding site. Copyright © 2017 Elsevier Inc. All rights reserved.

Simulating cholinesterase inhibition in birds caused by dietary insecticide exposure

USGS Publications Warehouse

Corson, M.S.; Mora, M.A.; Grant, W.E.

1998-01-01

We describe a stochastic simulation model that simulates avian foraging in an agricultural landscape to evaluate factors affecting dietary insecticide exposure and to predict post-exposure cholinesterase (ChE) inhibition. To evaluate the model, we simulated published field studies and found that model predictions of insecticide decay and ChE inhibition reasonably approximated most observed results. Sensitivity analysis suggested that foraging location usually influenced ChE inhibition more than diet preferences or daily intake rate. Although organophosphorus insecticides usually caused greater inhibition than carbamate insecticides, insecticide toxicity appeared only moderately important. When we simulated impact of heavy insecticide applications during breeding seasons of 15 wild bird species, mean maximum ChE inhibition in most species exceeded 20% at some point. At this level of inhibition, birds may experience nausea and/or may exhibit minor behavioral changes. Simulated risk peaked in April–May and August–September and was lowest in July. ChE inhibition increased with proportion of vegetation in the diet. This model, and ones like it, may help predict insecticide exposure of and sublethal ChE inhibition in grassland animals, thereby reducing dependence of ecological risk assessments on field studies alone.

Uncertainties in climate assessment for the case of aviation NO

PubMed Central

Holmes, Christopher D.; Tang, Qi; Prather, Michael J.

2011-01-01

Nitrogen oxides emitted from aircraft engines alter the chemistry of the atmosphere, perturbing the greenhouse gases methane (CH4) and ozone (O3). We quantify uncertainties in radiative forcing (RF) due to short-lived increases in O3, long-lived decreases in CH4 and O3, and their net effect, using the ensemble of published models and a factor decomposition of each forcing. The decomposition captures major features of the ensemble, and also shows which processes drive the total uncertainty in several climate metrics. Aviation-specific factors drive most of the uncertainty for the short-lived O3 and long-lived CH4 RFs, but a nonaviation factor dominates for long-lived O3. The model ensemble shows strong anticorrelation between the short-lived and long-lived RF perturbations (R2 = 0.87). Uncertainty in the net RF is highly sensitive to this correlation. We reproduce the correlation and ensemble spread in one model, showing that processes controlling the background tropospheric abundance of nitrogen oxides are likely responsible for the modeling uncertainty in climate impacts from aviation. PMID:21690364

Development, characterization and biocompatibility of chondroitin sulfate/poly(vinyl alcohol)/bovine bone powder porous biocomposite.

PubMed

da Silva, Gabriela T; Voss, Guilherme T; Kaplum, Vanessa; Nakamura, Celso V; Wilhelm, Ethel A; Luchese, Cristiane; Fajardo, André R

2017-03-01

Chondroitin sulfate (ChS), a sulfated glycosaminoglycan, poly(vinyl alcohol) (PVA) and bovine bone powder (BBP) were blended to form a novel eco-friendly biocomposite through cyclic freeze-thawing under mild conditions. The systematic investigation reveals that the content of BBP has a remarkable effect on the pore size, porosity, mechanical and liquid uptake properties and biodegradability. At 10wt.% BBP the biocomposite exhibited enhanced mechanical properties and biodegradability rate as compared to the pristine sample. Further, different properties of the biocomposite can be tailored according to the content of BBP. In vitro assays showed that ChS/PVA-BBP does not exert cytotoxicity against healthy cells. In vivo and ex vivo experiments revealed that ChS/PVA-BBP biocomposites are biocompatibility materials without exert pro-inflammatory responses. The biocomposite was completely biodegraded and bioresorbed after 15days of treatment. Taken together, BBP is a low-cost source of hydroxyapatite and collagen, which are insurance. All these results suggest that the biocomposite designed in this study is a promising biomaterial for potential skin tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Ab initio calculations and kinetic modeling of thermal conversion of methyl chloride: implications for gasification of biomass.

PubMed

Singla, Mallika; Rasmussen, Morten Lund; Hashemi, Hamid; Wu, Hao; Glarborg, Peter; Pelucchi, Matteo; Faravelli, Tiziano; Marshall, Paul

2018-04-25

Limitations in current hot gas cleaning methods for chlorine species from biomass gasification may be a challenge for end use such as gas turbines, engines, and fuel cells, all requiring very low levels of chlorine. During devolatilization of biomass, chlorine is released partly as methyl chloride. In the present work, the thermal conversion of CH3Cl under gasification conditions was investigated. A detailed chemical kinetic model for pyrolysis and oxidation of methyl chloride was developed and validated against selected experimental data from the literature. Key reactions of CH2Cl with O2 and C2H4 for which data are scarce were studied by ab initio methods. The model was used to analyze the fate of methyl chloride in gasification processes. The results indicate that CH3Cl emissions will be negligible for most gasification technologies, but could be a concern for fluidized bed gasifiers, in particular in low-temperature gasification. The present work illustrates how ab initio theory and chemical kinetic modeling can help to resolve emission issues for thermal processes in industrial scale.

Studies of electron-polyatomic-molecule collisions Applications to e-CH4

NASA Technical Reports Server (NTRS)

Lima, M. A. P.; Gibson, T. L.; Mckoy, V.; Huo, W. M.

1985-01-01

The first application of the Schwinger multichannel formulation to low-energy electron collisions with a nonlinear polyatomic target is reported. Integral and differential cross sections are obtained for e-CH4 collisions from 3 to 20 eV at the static-plus-exchange interaction level. In these studies, the exchange potential is directly evaluated and not approximated by local models. An interesting feature of the small-angle differential cross section is ascribed to polarization effects and not reproduced at the static-plus-exchange level. These differential cross sections are found to be in reasonable agreement with existing measurements at 7.5 eV and higher energies.

Overview of Nuclear Physics Data: Databases, Web Applications and Teaching Tools

NASA Astrophysics Data System (ADS)

McCutchan, Elizabeth

2017-01-01

The mission of the United States Nuclear Data Program (USNDP) is to provide current, accurate, and authoritative data for use in pure and applied areas of nuclear science and engineering. This is accomplished by compiling, evaluating, and disseminating extensive datasets. Our main products include the Evaluated Nuclear Structure File (ENSDF) containing information on nuclear structure and decay properties and the Evaluated Nuclear Data File (ENDF) containing information on neutron-induced reactions. The National Nuclear Data Center (NNDC), through the website www.nndc.bnl.gov, provides web-based retrieval systems for these and many other databases. In addition, the NNDC hosts several on-line physics tools, useful for calculating various quantities relating to basic nuclear physics. In this talk, I will first introduce the quantities which are evaluated and recommended in our databases. I will then outline the searching capabilities which allow one to quickly and efficiently retrieve data. Finally, I will demonstrate how the database searches and web applications can provide effective teaching tools concerning the structure of nuclei and how they interact. Work supported by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-98CH10886.

Advanced SPARQL querying in small molecule databases.

PubMed

Galgonek, Jakub; Hurt, Tomáš; Michlíková, Vendula; Onderka, Petr; Schwarz, Jan; Vondrášek, Jiří

2016-01-01

In recent years, the Resource Description Framework (RDF) and the SPARQL query language have become more widely used in the area of cheminformatics and bioinformatics databases. These technologies allow better interoperability of various data sources and powerful searching facilities. However, we identified several deficiencies that make usage of such RDF databases restrictive or challenging for common users. We extended a SPARQL engine to be able to use special procedures inside SPARQL queries. This allows the user to work with data that cannot be simply precomputed and thus cannot be directly stored in the database. We designed an algorithm that checks a query against data ontology to identify possible user errors. This greatly improves query debugging. We also introduced an approach to visualize retrieved data in a user-friendly way, based on templates describing visualizations of resource classes. To integrate all of our approaches, we developed a simple web application. Our system was implemented successfully, and we demonstrated its usability on the ChEBI database transformed into RDF form. To demonstrate procedure call functions, we employed compound similarity searching based on OrChem. The application is publicly available at https://bioinfo.uochb.cas.cz/projects/chemRDF.

Anti-knock quality of sugar derived levulinic esters and cyclic ethers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Miao; McCormick, Robert L.; Luecke, Jon

Here, the objective of this paper is to investigate the anti-knock quality of sugar-derived levulinic esters (methyl levulinate (ML) and ethyl levulinate (EL)) and cyclic ethers (furfuryl ethyl ether (FEE) and ethyl tetrahydrofurfuryl ether (ETE)). To this end, combustion experiments were carried out in both an engine and a constant volume autoignition device. The results from both apparati demonstrate that ML, EL and FEE have superior anti-knock quality than the reference Euro95 gasoline. ETE, conversely, performed markedly worse than the reference fuel on both setups and might therefore be a more appropriate fuel for compression ignition engines. The main reasonmore » of the distinctions in anti-knock quality can be found in the molecular structure of the neat biofuels. ML and EL are levulinic esters, with a ketone (C=O) functionality and an ester (C(=O)-O) group on the carbon chain. They can readily produce stable intermediates during the auto-ignition process, thereby slowing down the overall reaction rate. The unsaturated cyclic ether (FEE) has very strong ring C-H bonds. However, the saturated cyclic ether (ETE) has weak ring C-H bonds, which facilitate more readily ring opening reactions. Long side chains on the cyclic ethers further accelerate the reaction rate. Importantly for future research, our results suggest that IQT and engine experiments are interchangeable setups with respect to qualitative anti-knock quality evaluation of novel compounds.« less

Anti-knock quality of sugar derived levulinic esters and cyclic ethers

DOE PAGES

Tian, Miao; McCormick, Robert L.; Luecke, Jon; ...

2017-04-22

Here, the objective of this paper is to investigate the anti-knock quality of sugar-derived levulinic esters (methyl levulinate (ML) and ethyl levulinate (EL)) and cyclic ethers (furfuryl ethyl ether (FEE) and ethyl tetrahydrofurfuryl ether (ETE)). To this end, combustion experiments were carried out in both an engine and a constant volume autoignition device. The results from both apparati demonstrate that ML, EL and FEE have superior anti-knock quality than the reference Euro95 gasoline. ETE, conversely, performed markedly worse than the reference fuel on both setups and might therefore be a more appropriate fuel for compression ignition engines. The main reasonmore » of the distinctions in anti-knock quality can be found in the molecular structure of the neat biofuels. ML and EL are levulinic esters, with a ketone (C=O) functionality and an ester (C(=O)-O) group on the carbon chain. They can readily produce stable intermediates during the auto-ignition process, thereby slowing down the overall reaction rate. The unsaturated cyclic ether (FEE) has very strong ring C-H bonds. However, the saturated cyclic ether (ETE) has weak ring C-H bonds, which facilitate more readily ring opening reactions. Long side chains on the cyclic ethers further accelerate the reaction rate. Importantly for future research, our results suggest that IQT and engine experiments are interchangeable setups with respect to qualitative anti-knock quality evaluation of novel compounds.« less

Photophysical properties of wavelength-tunable methylammonium lead halide perovskite nanocrystals

DOE PAGES

Freppon, Daniel J.; Men, Long; Burkhow, Sadie J.; ...

2016-11-25

Here we present the time-correlated luminescence of isolated nanocrystals of five methylammonium lead mixed-halide perovskite compositions (CH 3NH 3PbBr 3$-$xI x) that were synthesized with varying iodide and bromide anion loading. All analyzed nanocrystals had a spherical morphology with diameters in the range of 2 to 32 nm. The luminescence maxima of CH 3NH 3PbBr 3$-$xI x nanocrystals were tuned to wavelengths ranging between 498 and 740 nm by varying the halide loading. Both CH 3NH 3PbI 3 and CH 3NH 3PbBr 3 nanocrystals exhibited no luminescence intermittency for more than 90% of the 250 s analysis time, as definedmore » by a luminescence intensity three standard deviations above the background. The mixed halide CH 3NH 3PbBr 0.75I 0.25, CH 3NH 3PbBr 0.50I 0.50, and CH 3NH 3PbBr 0.25I 0.75 nanocrystals exhibited luminescence intermittency in 18%, 4% and 26% of the nanocrystals, respectively. Irrespective of luminescence intermittency, luminescence intensities were classified for each nanocrystal as: (a) constant, (b) multimodal, (c) photobrightening, and (d) photobleaching. Finally, based on their photophysics, the CH 3NH 3PbBr 3$-$xI x nanocrystals can be expected to be useful in a wide-range of applications where low and non-intermittent luminescence is desirable, for example as imaging probes and in films for energy conversion devices.« less

Photophysical properties of wavelength-tunable methylammonium lead halide perovskite nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freppon, Daniel J.; Men, Long; Burkhow, Sadie J.

Here we present the time-correlated luminescence of isolated nanocrystals of five methylammonium lead mixed-halide perovskite compositions (CH 3NH 3PbBr 3$-$xI x) that were synthesized with varying iodide and bromide anion loading. All analyzed nanocrystals had a spherical morphology with diameters in the range of 2 to 32 nm. The luminescence maxima of CH 3NH 3PbBr 3$-$xI x nanocrystals were tuned to wavelengths ranging between 498 and 740 nm by varying the halide loading. Both CH 3NH 3PbI 3 and CH 3NH 3PbBr 3 nanocrystals exhibited no luminescence intermittency for more than 90% of the 250 s analysis time, as definedmore » by a luminescence intensity three standard deviations above the background. The mixed halide CH 3NH 3PbBr 0.75I 0.25, CH 3NH 3PbBr 0.50I 0.50, and CH 3NH 3PbBr 0.25I 0.75 nanocrystals exhibited luminescence intermittency in 18%, 4% and 26% of the nanocrystals, respectively. Irrespective of luminescence intermittency, luminescence intensities were classified for each nanocrystal as: (a) constant, (b) multimodal, (c) photobrightening, and (d) photobleaching. Finally, based on their photophysics, the CH 3NH 3PbBr 3$-$xI x nanocrystals can be expected to be useful in a wide-range of applications where low and non-intermittent luminescence is desirable, for example as imaging probes and in films for energy conversion devices.« less

Study on the electronic structure of Al12N12 and Al12P12 fullerene-like nano-clusters upon adsorption of CH3F and CH3Cl

NASA Astrophysics Data System (ADS)

Shokuhi Rad, A.; Zareyee, D.; Pouralijan Foukolaei, V.; Kamyab Moghadas, B.; Peyravi, M.

2016-11-01

We study the interaction of two mono-halomethanes (CH3F and CH3Cl) on Al12N12 and Al12P12 fullerene-like nano-clusters based on density functional theory (DFT). We search on fully optimised adsorbed systems by theoretical investigation considering binding energies, total density of states, natural bond orbital (NBO) charges, and molecular electrostatic potential. We found that the direction of electron transfer is from halomethane to nano-cluster for all systems, indicating p-type semiconductor property of the mentioned nano-clusters. The interaction energy of halomethanes on nano-clusters is evaluated with dispersion corrected (wB97XD) and non-corrected (B3LYP) methods in order to estimate the dispersion effects. The binding energies are found in order of Al12N12-CH3F > Al12N12-CH3Cl > Al12P12-CH3F > Al12P12-CH3Cl with the values of -102.7, -83.7, -64.2, and -48.9 kJ mol-1 based on wB97XD, respectively. We found significant changes in the location of HOMO as well as LUMO of nano-clusters upon adsorption of the above-mentioned molecules. As a result, we suggest the suitability of Al12N12 nano-cluster as a strong adsorbent for practical applications.

Application of activated carbon modified by acetic acid in adsorption and separation of CO2 and CH4

NASA Astrophysics Data System (ADS)

Song, Xue; Wang, Li'ao; Zeng, Yunmin; Zhan, Xinyuan; Gong, Jian; Li, Tong

2018-03-01

Compared with the methods to modify the activated carbons by alkalis for gas adsorption, fewer studies of that by organic acids have been reported. The acid modified activated carbons are usually utilized to treat wastewater, whereas the application in the separation of CO2/CH4 has less been studied. In this study, acetic acid was used to modify activated carbon. N2 adsorption/desorption isotherms and FT-IR were adopted to describe the properties of the samples. According to the adsorption data of pure gas component at 298 K, the gas adsorbed amount and the selectivity on the modified samples were larger than that on the raw sample. Besides, the adsorbed amount of CO2 and the selectivity on 15H-AC in the adsorption breakthrough experiments showed better performance. The results confirm that the method to modify the activated carbons with acetic acid is feasible to improve the adsorption capacity and the separation effect of CO2/CH4.

Investigation of the Behavior of Fuel in the Intake Manifold and its Relation to S. I. Engines, 1980-1983

NASA Astrophysics Data System (ADS)

Servati, Hamid Beyragh

A liquid fuel film formation on the walls of an intake manifold adversely affects the engine performance and alters the overall air/fuel ratio from that scheduled by a fuel injector or carburetor and leads to adverse effects in vehicle driveability, exhaust emissions, and fuel economy. In this dissertation, the intake manifold is simulated by a horizontal circular duct. A model is provided to predict the rate of deposition and evaporation of the droplets in the intake manifold. The liquid fuel flow rate into the cylinders, mean film velocity and film thickness are determined as functions of engine parameters for both steady and transient operating conditions of the engine. A mathematical engine model is presented to simulate the dynamic interactions of the various engine components such as the air/fuel inlet element, intake manifold, combustion, dynamics and exhaust emissions. Inputs of the engine model are the intake manifold pressure and temperature, throttle angle, and air/fuel ratio. The observed parameters are the histories of fuel film thickness and velocity, fuel consumption, engine speed, engine speed hesitation time, and histories of CO, CO(,2), NO(,x), CH(,n), and O(,2). The effects of different air/fuel ratio control strategies on engine performance and observed parameters are also shown.

Extremophilic polysaccharide nanoparticles for cancer nanotherapy and evaluation of antioxidant properties.

PubMed

Raveendran, Sreejith; Palaninathan, Vivekanandan; Nagaoka, Yutaka; Fukuda, Takahiro; Iwai, Seiki; Higashi, Toshiaki; Mizuki, Toru; Sakamoto, Yasushi; Mohanan, P V; Maekawa, Toru; Kumar, D Sakthi

2015-05-01

Polysaccharides that show finest bioactivities and physicochemical properties are always promising for bionanoscience applications. Mauran is such a macromolecule extracted from halophilic bacterium, Halomonas maura for biotechnology and nanoscience applications. Antioxidant properties of MR/CH nanoparticles were studied using biochemical assays to prove the versatility of these test nanoparticles for biomedical applications. Here, we demonstrate the prospects of extremophilic polysaccharide, mauran based nanoparticles for scavenging reactive oxygen species in both in vitro and ex vivo conditions. 5-fluorouracil loaded MR/CH nanoparticles were tested for anticancer proliferation and compared their therapeutic efficiency using breast adenocarcinoma and glioma cells. Fluorescently labeled nanoparticles were employed to show the cellular uptake of these nanocarriers using confocal microscopic imaging and flow cytometry. Copyright © 2015 Elsevier B.V. All rights reserved.

Instability diagnosis and syntrophic acetate oxidation during thermophilic digestion of vegetable waste.

PubMed

Li, Dong; Ran, Yi; Chen, Lin; Cao, Qin; Li, Zhidong; Liu, Xiaofeng

2018-08-01

Effective process monitoring and instability diagnosis are important for stable anaerobic digestion (AD) of vegetable waste (VW). In order to evaluate the performance of thermophilic digestion of VW, to make early diagnosis for instability after organic overload, and to reveal the dynamics of microbial community under different running states, thermophilic AD of VW was carried out under improved organic loading rates (OLR) of 0.5-2.5 g volatile solid (VS)/(L ∙ d) in this study. Gaseous parameters including volumetric methane production rate (VMPR), CH 4 , CO 2 , and H 2 concentrations, and liquid parameters including pH, oxidation-reduction potential, volatile fatty acid (VFA), and total alkalinity (TA), bicarbonate alkalinity (BA), intermediate alkalinity (IA), and ammonia, were monitored. The coupling parameters, such as the CH 4 /CO 2 , VFA/BA, and BA/TA ratios were also used to evaluate stability. The dynamics of syntrophic acetate-oxidizing bacteria (SAOB), acetoclastic methanogens (AM), and hydrogenotrophic methanogens (HM) were analyzed by high-throughput sequencing. The main methanogenic bacteria were HM (Methanothermobacter) during the start-up period of OLR 0.5 gVS/(L ∙ d), while they were AM (Methanosarcina) during the stable period of OLR of 1.0 gVS/(L ∙ d). The VMPR of stable period was about 0.29 L/(L · d) with total VFA concentration below 100 mg/L, CH 4 /CO 2  > 1.3, and BA/TA>0.9. The first instability due to the accumulation of VFA and self-recovery due to syntrophic acetate oxidation occurred at an OLR of 1.5 gVS/(L ∙ d). The syntrophic acetate-oxidizing bacteria probably belong to genus S1 (family Thermotogaceae). The digestion failed at an OLR of 2.0 g VS/(L · d). H 2 was only detected during collapsed period instead of instable period. The total ammonia nitrogen loss and bicarbonate alkalinity (BA) reduction were the primary causes for the instability of AD of VW without effluent recirculation. Compared with single parameters, the CH 4 /CO 2 and BA/total alkalinity (TA) ratios are recommended as early warning indicators for engineering applications of thermophilic AD of VW. Copyright © 2018 Elsevier Ltd. All rights reserved.

Laser-induced breakdown ignition in a gas fed two-stroke engine

NASA Astrophysics Data System (ADS)

Loktionov, E. Y.; Pasechnikov, N. A.; Telekh, V. D.

2018-01-01

Laser-induced ignition for internal combustion engines is investigated intensively after demonstration of a compact ‘laser plug’ possibility. Laser spark benefits as compared to traditional spark plugs are higher compression rate, and possibility of almost any fuel ignition, so lean mixtures burning with lower temperatures could reduce harmful exhausts (NO x , CH, etc). No need in electrode and possibility for multi-point, linear or circular ignition can make combustion even more effective. Laser induced combustion wave appears faster and is more stable in time, than electric one, so can be used for ramjets, chemical thrusters, and gas turbines. To the best of our knowledge, we have performed laser spark ignition of a gas fed two-stroke engine for the first time. Combustion temperature and pressure, exhaust composition, ignition timing were investigated at laser and compared to a regular electric spark ignition in a two-stroke model engine. Presented results show possibility for improvement of two-stroke engines performance, in terms of rotation rate increase and NO x emission reduction. Such compact engines using locally mined fuel could be highly demanded in remote Arctic areas.

Inverse Estimation of California Methane Emissions and Their Uncertainties using FLEXPART-WRF

NASA Astrophysics Data System (ADS)

Cui, Y.; Brioude, J. F.; Angevine, W. M.; McKeen, S. A.; Peischl, J.; Nowak, J. B.; Henze, D. K.; Bousserez, N.; Fischer, M. L.; Jeong, S.; Liu, Z.; Michelsen, H. A.; Santoni, G.; Daube, B. C.; Kort, E. A.; Frost, G. J.; Ryerson, T. B.; Wofsy, S. C.; Trainer, M.

2015-12-01

Methane (CH4) has a large global warming potential and mediates global tropospheric chemistry. In California, CH4 emissions estimates derived from "top-down" methods based on atmospheric observations have been found to be greater than expected from "bottom-up" population-apportioned national and state inventories. Differences between bottom-up and top-down estimates suggest that the understanding of California's CH4 sources is incomplete, leading to uncertainty in the application of regulations to mitigate regional CH4 emissions. In this study, we use airborne measurements from the California research at the Nexus of Air Quality and Climate Change (CalNex) campaign in 2010 to estimate CH4 emissions in the South Coast Air Basin (SoCAB), which includes California's largest metropolitan area (Los Angeles), and in the Central Valley, California's main agricultural and livestock management area. Measurements from 12 daytime flights, prior information from national and regional official inventories (e.g. US EPA's National Emission Inventory, the California Air Resources Board inventories, the Liu et al. Hybrid Inventory, and the California Greenhouse Gas Emissions Measurement dataset), and the FLEXPART-WRF transport model are used in our mesoscale Bayesian inverse system. We compare our optimized posterior CH4 inventory to the prior bottom-up inventories in terms of total emissions (Mg CH4/hr) and the spatial distribution of the emissions (0.1 degree), and quantify uncertainties in our posterior estimates. Our inversions show that the oil and natural gas industry (extraction, processing and distribution) is the main source accounting for the gap between top-down and bottom-up inventories over the SoCAB, while dairy farms are the largest CH4 source in the Central Valley. CH4 emissions of dairy farms in the San Joaquin Valley and variations of CH4 emissions in the rice-growing regions of Sacramento Valley are quantified and discussed. We also estimate CO and NH3 surface fluxes and use their observed correlation with CH4 mixing ratio to further evaluate our CH4 total emission estimates, and understand the spatial distribution of CH4 emissions.

Performance evaluation of an advanced air-fuel ratio controller on a stationary, rich-burn natural gas engine

NASA Astrophysics Data System (ADS)

Kochuparampil, Roshan Joseph

The advent of an era of abundant natural gas is making it an increasingly economical fuel source against incumbents such as crude oil and coal, in end-use sectors such as power generation, transportation and industrial chemical production, while also offering significant environmental benefits over these incumbents. Equipment manufacturers, in turn, are responding to widespread demand for power plants optimized for operation with natural gas. In several applications such as distributed power generation, gas transmission, and water pumping, stationary, spark-ignited, natural gas fueled internal combustion engines (ICEs) are the power plant of choice (over turbines) owing to their lower equipment and operational costs, higher thermal efficiencies across a wide load range, and the flexibility afforded to end-users when building fine-resolution horsepower topologies: modular size increments ranging from 100 kW -- 2 MW per ICE power plant compared to 2 -- 5 MW per turbine power plant. Under the U.S. Environment Protection Agency's (EPA) New Source Performance Standards (NSPS) and Reciprocating Internal Combustion Engine National Emission Standards for Hazardous Air Pollutants (RICE NESHAP) air quality regulations, these natural gas power plants are required to comply with stringent emission limits, with several states mandating even stricter emissions norms. In the case of rich-burn or stoichiometric natural gas ICEs, very high levels of sustained emissions reduction can be achieved through exhaust after-treatment that utilizes Non Selective Catalyst Reduction (NSCR) systems. The primary operational constraint with these systems is the tight air-fuel ratio (AFR) window of operation that needs to be maintained if the NSCR system is to achieve simultaneous reduction of carbon monoxide (CO), nitrogen oxides (NOx), total hydrocarbons (THC), volatile organic compounds (VOCs), and formaldehyde (CH 2O). Most commercially available AFR controllers utilizing lambda (oxygen) sensor feedback are unable to maintain engine AFR within the required range owing to drift in sensor output over time. In this thesis, the emissions compliance performance of an AFR controller is evaluated over a 6-month period on an engine driving a gas compressor in an active natural gas production field. This AFR controller differentiates itself from other commercially available products by employing a lambda sensor that has been engineered against sensor drift, making it better suited for natural gas engine applications. Also included in this study are the controller's responses to transient loads, diurnal performance, adaptability to seasonal variations in ambient temperature, fuel quality variations (in wellhead gas), engine health considerations for proper AFR control, and controller calibration sensitivity when replacing lambda sensors. During the first three months of operation and subsequent diurnal tests, the controller's performance as a multi-point AFR control system was consistent, demonstrating appropriate AFR adjustments to variation in engine operation, over a wide range of ambient conditions, despite high consumption rate of engine lubrication oil. For the remainder the test, the high levels of lubrication oil consumption, compromised the ability to verify controller performance.

Combination of wet irrigation and nitrification inhibitor reduced nitrous oxide and methane emissions from a rice cropping system.

PubMed

Liu, Gang; Yu, Haiyang; Zhang, Guangbin; Xu, Hua; Ma, Jing

2016-09-01

To conserve water resources and guarantee food security, a new technology termed as "wet irrigation" is developed and practiced in rice fields; thus, its impact on radiative forcing derived from nitrous oxide (N2O) and methane (CH4) emissions merits serious attention. Dicyandiamide (DCD), a kind of nitrification inhibitor, is proposed as a viable means to mitigate greenhouse gas (GHG) emission while enhancing crop productivity. However, little is known about the response of GHG emission and grain yield to DCD application in a rice system under wet irrigation. In these regard, effects of water regime and DCD application on CH4 and N2O emissions, grain yield, global warming potential (GWP), and greenhouse gas intensity (GHGI) from rice fields were studied. For this study, a field experiment, designed: Treatment II (intermittent irrigation), Treatment WI (wet irrigation), Treatment IID (II plus DCD), and Treatment WID (WI plus DCD), was conducted in Jurong, Jiangsu Province, China, from 2011 to 2012. Relative to Treatment II, Treatment WI decreased CH4 emission significantly by 49-71 % while increasing N2O emission by 33-72 %. By integrating CH4 and N2O emissions and grain yield, Treatment WI was 20-28 and 11-15 % lower than Treatment II in GWP and GHGI, respectively. The use of DCD under wet irrigation reduced N2O emission significantly by 25-38 % (p < 0.05) and CH4 emission by 7-8 %, relative to Treatment WI, resulting in a decline of 18-30 % in GWP. Due to the increase in N use efficiency, maximal grain yield (6-7 %) and minimal GHGI (22-34 %) was observed in Treatment WID. These findings indicate that combined application of N fertilizer and DCD is a win-win strategy in water-saving high-yield rice production with less GHG emission.

Analytical network process based optimum cluster head selection in wireless sensor network.

PubMed

Farman, Haleem; Javed, Huma; Jan, Bilal; Ahmad, Jamil; Ali, Shaukat; Khalil, Falak Naz; Khan, Murad

2017-01-01

Wireless Sensor Networks (WSNs) are becoming ubiquitous in everyday life due to their applications in weather forecasting, surveillance, implantable sensors for health monitoring and other plethora of applications. WSN is equipped with hundreds and thousands of small sensor nodes. As the size of a sensor node decreases, critical issues such as limited energy, computation time and limited memory become even more highlighted. In such a case, network lifetime mainly depends on efficient use of available resources. Organizing nearby nodes into clusters make it convenient to efficiently manage each cluster as well as the overall network. In this paper, we extend our previous work of grid-based hybrid network deployment approach, in which merge and split technique has been proposed to construct network topology. Constructing topology through our proposed technique, in this paper we have used analytical network process (ANP) model for cluster head selection in WSN. Five distinct parameters: distance from nodes (DistNode), residual energy level (REL), distance from centroid (DistCent), number of times the node has been selected as cluster head (TCH) and merged node (MN) are considered for CH selection. The problem of CH selection based on these parameters is tackled as a multi criteria decision system, for which ANP method is used for optimum cluster head selection. Main contribution of this work is to check the applicability of ANP model for cluster head selection in WSN. In addition, sensitivity analysis is carried out to check the stability of alternatives (available candidate nodes) and their ranking for different scenarios. The simulation results show that the proposed method outperforms existing energy efficient clustering protocols in terms of optimum CH selection and minimizing CH reselection process that results in extending overall network lifetime. This paper analyzes that ANP method used for CH selection with better understanding of the dependencies of different components involved in the evaluation process.

Analytical network process based optimum cluster head selection in wireless sensor network

PubMed Central

Javed, Huma; Jan, Bilal; Ahmad, Jamil; Ali, Shaukat; Khalil, Falak Naz; Khan, Murad

2017-01-01

Wireless Sensor Networks (WSNs) are becoming ubiquitous in everyday life due to their applications in weather forecasting, surveillance, implantable sensors for health monitoring and other plethora of applications. WSN is equipped with hundreds and thousands of small sensor nodes. As the size of a sensor node decreases, critical issues such as limited energy, computation time and limited memory become even more highlighted. In such a case, network lifetime mainly depends on efficient use of available resources. Organizing nearby nodes into clusters make it convenient to efficiently manage each cluster as well as the overall network. In this paper, we extend our previous work of grid-based hybrid network deployment approach, in which merge and split technique has been proposed to construct network topology. Constructing topology through our proposed technique, in this paper we have used analytical network process (ANP) model for cluster head selection in WSN. Five distinct parameters: distance from nodes (DistNode), residual energy level (REL), distance from centroid (DistCent), number of times the node has been selected as cluster head (TCH) and merged node (MN) are considered for CH selection. The problem of CH selection based on these parameters is tackled as a multi criteria decision system, for which ANP method is used for optimum cluster head selection. Main contribution of this work is to check the applicability of ANP model for cluster head selection in WSN. In addition, sensitivity analysis is carried out to check the stability of alternatives (available candidate nodes) and their ranking for different scenarios. The simulation results show that the proposed method outperforms existing energy efficient clustering protocols in terms of optimum CH selection and minimizing CH reselection process that results in extending overall network lifetime. This paper analyzes that ANP method used for CH selection with better understanding of the dependencies of different components involved in the evaluation process. PMID:28719616

Raman spectroscopic characterization of gas mixtures. II. Quantitative composition and pressure determination of the CO2-CH4 system

USGS Publications Warehouse

Seitz, J.C.; Pasteris, J.D.; Chou, I.-Ming

1996-01-01

Raman spectral parameters were determined for the v1 band of CH4 and the v1 and 2v2 bands (Fermi diad) of CO2 in pure CO2 and CO2-CH4 mixtures at pressures up to 700 bars and room temperature. Peak position, area, height, and width were investigated as functions of pressure and composition. The peak positions of the CH4 and CO2 bands shift to lower relative wavenumbers as fluid pressure is increased. The peak position of the lower-wavenumber member of the Fermi diad for CO2 is sensitive to fluid composition, whereas the peak positions of the CH4 band and the upper Fermi diad member for CO2 are relatively insensitive in the CO2-CH4 system. The magnitude of the shifts in each of the three peak positions (as a function of pressure) is sufficient to be useful as a monitor of fluid pressure. The relative molar proportions in a CO2-CH4 mixture may be determined from the peak areas: the ratio of the peak areas of the CH4 band and the CO2 upper Fermi diad member is very sensitive to composition, whereas above about 100 bars, it is insensitive to pressure. Likewise, the peak height ratio is very sensitive to composition but also to fluid pressure. The individual peak widths of CO2 and CH4, as well as the ratios of the widths of the CH4 peak to the CO2 peaks are a sensitive function of pressure and, to a lesser extent, composition. Thus, upon determination of fluid composition, the peak width ratios may be used as a monitor of fluid pressure. The application of these spectral parameters to a suite of natural CO2-CH4 inclusions has yielded internally-consistent, quantitative determinations of the fluid composition and density.

Application of stable isotope measurements and microbiological analysis for detecting methanogenic activity in a temperate forest wetland

NASA Astrophysics Data System (ADS)

Itoh, M.; Katsuyama, C.; Kondo, N.; Ohte, N.; Kato, K.

2009-12-01

Generally, forest soils act as a sink for methane (CH4). However, wetlands in riparian zones are recently reported to be “hot spots” of CH4 emissions, especially in forests under a humid climate. To understand how environmental conditions (i.e. hydrological and/or geomorphic condition) control on CH4 production, we investigated both methanogenic pathways (CO2/H2 reduction and acetate fermentation) and metahanogenic microbial communities in a wetland in a temperate forest catchment, central Japan. We used stable carbon isotopic analysis for detecting change in methanogenic pathways, and applied microbiological analysis for understanding the structure of methanogenic community. CH4 emission rates in wetland were strongly dependent on soil temperatures, and were highest in summer and lowest in winter. δ13CO2 increased with CH4 production in every summer, suggesting preferential use of 12CO2 as substrate for CO2/H2 reduction methanogenesis during high CH4 production period. δ13CH4 also increased in summer with δ13CO2. δ13CH4 changed more wildly than δ13CO2 did in summer with normal precipitation when CH4 production was strongly activated under high temperature and high groundwater table condition. This indicates increase in acetoclastic methanogenesis under hot and wet condition, considering that acetclastic methnogens produce heavier CH4 than that from CO2/H2 reducing pathway. Methanogen community composition estimated by cloning and sequence analyses implied that both acetoclastic and CO2/H2 reducing methanogens prevailed in wetland soil sampled in summer. This was consistent with the results of isotope measuremaents. Our results contribute to understand fully how the CH4 production changes with environmental conditions, with considering the activities of both main methanogenic pathway (from CO2 and acetate).

Partitioning of CH4 and CO2 Production Originating from Rice Straw, Soil and Root Organic Carbon in Rice Microcosms

PubMed Central

Yuan, Quan; Pump, Judith; Conrad, Ralf

2012-01-01

Flooded rice fields are an important source of the greenhouse gas CH4. Possible carbon sources for CH4 and CO2 production in rice fields are soil organic matter (SOM), root organic carbon (ROC) and rice straw (RS), but partitioning of the flux between the different carbon sources is difficult. We conducted greenhouse experiments using soil microcosms planted with rice. The soil was amended with and without 13C-labeled RS, using two 13C-labeled RS treatments with equal RS (5 g kg−1 soil) but different δ13C of RS. This procedure allowed to determine the carbon flux from each of the three sources (SOM, ROC, RS) by determining the δ13C of CH4 and CO2 in the different incubations and from the δ13C of RS. Partitioning of carbon flux indicated that the contribution of ROC to CH4 production was 41% at tillering stage, increased with rice growth and was about 60% from the booting stage onwards. The contribution of ROC to CO2 was 43% at tillering stage, increased to around 70% at booting stage and stayed relatively constant afterwards. The contribution of RS was determined to be in a range of 12–24% for CH4 production and 11–31% for CO2 production; while the contribution of SOM was calculated to be 23–35% for CH4 production and 13–26% for CO2 production. The results indicate that ROC was the major source of CH4 though RS application greatly enhanced production and emission of CH4 in rice field soil. Our results also suggest that data of CH4 dissolved in rice field could be used as a proxy for the produced CH4 after tillering stage. PMID:23162678

Improved quantification of microbial CH4 oxidation efficiency in arctic wetland soils using carbon isotope fractionation

NASA Astrophysics Data System (ADS)

Preuss, I.; Knoblauch, C.; Gebert, J.; Pfeiffer, E.-M.

2013-04-01

Permafrost-affected tundra soils are significant sources of the climate-relevant trace gas methane (CH4). The observed accelerated warming of the arctic will cause deeper permafrost thawing, followed by increased carbon mineralization and CH4 formation in water-saturated tundra soils, thus creating a positive feedback to climate change. Aerobic CH4 oxidation is regarded as the key process reducing CH4 emissions from wetlands, but quantification of turnover rates has remained difficult so far. The application of carbon stable isotope fractionation enables the in situ quantification of CH4 oxidation efficiency in arctic wetland soils. The aim of the current study is to quantify CH4 oxidation efficiency in permafrost-affected tundra soils in Russia's Lena River delta based on stable isotope signatures of CH4. Therefore, depth profiles of CH4 concentrations and δ13CH4 signatures were measured and the fractionation factors for the processes of oxidation (αox) and diffusion (αdiff) were determined. Most previous studies employing stable isotope fractionation for the quantification of CH4 oxidation in soils of other habitats (such as landfill cover soils) have assumed a gas transport dominated by advection (αtrans = 1). In tundra soils, however, diffusion is the main gas transport mechanism and diffusive stable isotope fractionation should be considered alongside oxidative fractionation. For the first time, the stable isotope fractionation of CH4 diffusion through water-saturated soils was determined with an αdiff = 1.001 ± 0.000 (n = 3). CH4 stable isotope fractionation during diffusion through air-filled pores of the investigated polygonal tundra soils was αdiff = 1.013 ± 0.003 (n = 18). Furthermore, it was found that αox differs widely between sites and horizons (mean αox = 1.017 ± 0.009) and needs to be determined on a case by case basis. The impact of both fractionation factors on the quantification of CH4 oxidation was analyzed by considering both the potential diffusion rate under saturated and unsaturated conditions and potential oxidation rates. For a submerged, organic-rich soil, the data indicate a CH4 oxidation efficiency of 50% at the anaerobic-aerobic interface in the upper horizon. The improved in situ quantification of CH4 oxidation in wetlands enables a better assessment of current and potential CH4 sources and sinks in permafrost-affected ecosystems and their potential strengths in response to global warming.

Improved quantification of microbial CH4 oxidation efficiency in Arctic wetland soils using carbon isotope fractionation

NASA Astrophysics Data System (ADS)

Preuss, I.; Knoblauch, C.; Gebert, J.; Pfeiffer, E.-M.

2012-12-01

Permafrost-affected tundra soils are significant sources of the climate-relevant trace gas methane (CH4). The observed accelerated warming of the Arctic will cause a deeper permafrost thawing followed by increased carbon mineralization and CH4 formation in water saturated tundra soils which might cause a positive feedback to climate change. Aerobic CH4 oxidation is regarded as the key process reducing CH4 emissions from wetlands, but quantification of turnover rates has remained difficult so far. The application of carbon stable isotope fractionation enables the in situ quantification of CH4 oxidation efficiency in arctic wetland soils. The aim of the current study is to quantify CH4 oxidation efficiency in permafrost-affected tundra soils in Russia's Lena River Delta based on stable isotope signatures of CH4. Therefore, depth profiles of CH4 concentrations and δ13CH4-signatures were measured and the fractionation factors for the processes of oxidation (αox) and diffusion (αdiff) were determined. Most previous studies employing stable isotope fractionation for the quantification of CH4 oxidation in soils of other habitats (e.g. landfill cover soils) have assumed a gas transport dominated by advection (αtrans = 1). In tundra soils, however, diffusion is the main gas transport mechanism, aside from ebullition. Hence, diffusive stable isotope fractionation has to be considered. For the first time, the stable isotope fractionation of CH4 diffusion through water-saturated soils was determined with an αdiff = 1.001 ± 0.000 (n = 3). CH4 stable isotope fractionation during diffusion through air-filled pores of the investigated polygonal tundra soils was αdiff = 1.013 ± 0.003 (n = 18). Furthermore, it was found that αox differs widely between sites and horizons (mean αox, = 1.017 ± 0.009) and needs to be determined individually. The impact of both fractionation factors on the quantification of CH4 oxidation was analyzed by considering both the potential diffusion rate under saturated and unsaturated conditions and potential oxidation rates. For a submerged organic rich soil, the data indicate a CH4 oxidation efficiency of 50% at the anaerobic-aerobic interface in the upper horizon. The improved in situ quantification of CH4 oxidation in wetlands enables a better assessment of current and potential CH4 sources and sinks in permafrost affected ecosystems and their potential strengths in response to global warming.

SureChEMBL: a large-scale, chemically annotated patent document database.

PubMed

Papadatos, George; Davies, Mark; Dedman, Nathan; Chambers, Jon; Gaulton, Anna; Siddle, James; Koks, Richard; Irvine, Sean A; Pettersson, Joe; Goncharoff, Nicko; Hersey, Anne; Overington, John P

2016-01-04

SureChEMBL is a publicly available large-scale resource containing compounds extracted from the full text, images and attachments of patent documents. The data are extracted from the patent literature according to an automated text and image-mining pipeline on a daily basis. SureChEMBL provides access to a previously unavailable, open and timely set of annotated compound-patent associations, complemented with sophisticated combined structure and keyword-based search capabilities against the compound repository and patent document corpus; given the wealth of knowledge hidden in patent documents, analysis of SureChEMBL data has immediate applications in drug discovery, medicinal chemistry and other commercial areas of chemical science. Currently, the database contains 17 million compounds extracted from 14 million patent documents. Access is available through a dedicated web-based interface and data downloads at: https://www.surechembl.org/. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Comparative Study of Ether-Based Electrolytes for Application in Lithium-Sulfur Battery.

PubMed

Carbone, Lorenzo; Gobet, Mallory; Peng, Jing; Devany, Matthew; Scrosati, Bruno; Greenbaum, Steve; Hassoun, Jusef

2015-07-01

Herein, we report the characteristics of electrolytes using various ether-solvents with molecular composition CH3O[CH2CH2O]nCH3, differing by chain length, and LiCF3SO3 as the lithium salt. The electrolytes, considered as suitable media for lithium-sulfur batteries, are characterized in terms of thermal properties (TGA, DSC), lithium ion conductivity, lithium interface stability, cyclic voltammetry, self-diffusion properties of the various components, and lithium transference number measured by NMR. Furthermore, the electrolytes are characterized in lithium cells using a sulfur-carbon composite cathode by galvanostatic charge-discharge tests. The results clearly evidence the influence of the solvent chain length on the species mobility within the electrolytes that directly affects the behavior in lithium sulfur cell. The results may effectively contribute to the progress of an efficient, high-energy lithium-sulfur battery.

Spectroscopy of the low-frequency vibrational modes of CH3+ isotopologues

NASA Astrophysics Data System (ADS)

Asvany, Oskar; Thorwirth, Sven; Redlich, Britta; Schlemmer, Stephan

2018-05-01

The low-frequency stretching and bending vibrations of the isotopologues CH2D+,CD2H+ and CD3+ have been recorded at low temperature and low resolution. For this, a cryogenic 22-pole trapping machine coupled to an IR beamline of the FELIX free electron laser facility has been used. To record the overview spectra, the laser induced reactions CDm Hn+ + H2 → hν CDm-1 Hn+1+ +HD have been applied for these species. As this scheme is not applicable to CH3+, the latter has been tagged with He and subsequently dissociated by the IR beam. For the resulting CH3+ -He spectrum, broad features are observed below 1000 cm-1 possibly related to vibrational motions involving the He atom. The extracted vibrational band positions for all species are compared to results from high-level quantum-chemical calculations.

Final Report

NASA Technical Reports Server (NTRS)

1995-01-01

This cooperative agreement explored the novel polymerization of vinylsilane, alone and in combination with other alkenylsilanes, alkylsilanes, and/or crosslinking agents, using dimethyltitanocene as homogeneous catalyst. The reactions were found to be initiated photochemically under mild conditions, and no hydrogen gas was evolved when alkenylsilanes were polymerized. The polymers were found to have predominately a carbosilane-type backbone containing -SiH2-CH2-CH2-Si and -SiH2-CH(CH3)-Si type linkages. The mechanism of polymerization was found to be step-growth. Despite the relatively low molecular weight of the polymer (M(sub n) - 500 and M(sub W) - 1500), pyrolysis resulted in conversion to C-rich SiC ceramic in high char yields (-60%). Copolymerization with methylsilane resulted in higher chars and more crystalline polymer. Addition of crosslinking agents such as polybutadiene or methyltrivinylsilane increased the viscosity of the polymer produced and enabled application as coatings to fiber toes.

Coassembly of Lysozyme and Amphiphilic Biomolecules Driven by Unimer-Aggregate Equilibrium.

PubMed

Tao, Yuanyuan; Ma, Xiaoteng; Cai, Yaqian; Liu, Li; Zhao, Hanying

2018-04-12

Synthesis and self-assembly of bioconjugates composed of proteins and synthetic molecules have been widely studied because of the potential applications in medicine, biotechnology, and nanotechnology. One of the challenging research studies in this area is to develop organic solvent-free approaches to the synthesis and self-assembly of amphiphilic bioconjugates. In this research, dialysis-assisted approach, a method based on unimer-aggregate equilibrium, was applied in the coassembly of lysozyme and conjugate of cholesterol and glutathione (Ch-GSH). In phosphate buffer solution, amphiphilic Ch-GSH conjugate self-assembles into vesicles, and the vesicle solution is dialyzed against lysozyme solution. Negatively charged Ch-GSH unimers produced in the unimer-vesicle exchange equilibrium, diffuse across the dialysis membrane and have electrostatic interaction with positively charged lysozyme, resulting in the formation of Ch-GSH-lysozyme bioconjugate. Above a critical concentration, the three-component bioconjugate molecules self-assemble into bioactive vesicles.

SureChEMBL: a large-scale, chemically annotated patent document database

PubMed Central

Papadatos, George; Davies, Mark; Dedman, Nathan; Chambers, Jon; Gaulton, Anna; Siddle, James; Koks, Richard; Irvine, Sean A.; Pettersson, Joe; Goncharoff, Nicko; Hersey, Anne; Overington, John P.

2016-01-01

SureChEMBL is a publicly available large-scale resource containing compounds extracted from the full text, images and attachments of patent documents. The data are extracted from the patent literature according to an automated text and image-mining pipeline on a daily basis. SureChEMBL provides access to a previously unavailable, open and timely set of annotated compound-patent associations, complemented with sophisticated combined structure and keyword-based search capabilities against the compound repository and patent document corpus; given the wealth of knowledge hidden in patent documents, analysis of SureChEMBL data has immediate applications in drug discovery, medicinal chemistry and other commercial areas of chemical science. Currently, the database contains 17 million compounds extracted from 14 million patent documents. Access is available through a dedicated web-based interface and data downloads at: https://www.surechembl.org/. PMID:26582922

Gastric cancer differentiation using Fourier transform near-infrared spectroscopy with unsupervised pattern recognition

NASA Astrophysics Data System (ADS)

Yi, Wei-song; Cui, Dian-sheng; Li, Zhi; Wu, Lan-lan; Shen, Ai-guo; Hu, Ji-ming

2013-01-01

The manuscript has investigated the application of near-infrared (NIR) spectroscopy for differentiation gastric cancer. The 90 spectra from cancerous and normal tissues were collected from a total of 30 surgical specimens using Fourier transform near-infrared spectroscopy (FT-NIR) equipped with a fiber-optic probe. Major spectral differences were observed in the CH-stretching second overtone (9000-7000 cm-1), CH-stretching first overtone (6000-5200 cm-1), and CH-stretching combination (4500-4000 cm-1) regions. By use of unsupervised pattern recognition, such as principal component analysis (PCA) and cluster analysis (CA), all spectra were classified into cancerous and normal tissue groups with accuracy up to 81.1%. The sensitivity and specificity was 100% and 68.2%, respectively. These present results indicate that CH-stretching first, combination band and second overtone regions can serve as diagnostic markers for gastric cancer.

The Coupled Photochemistry of Ammonia and Acetylene: Applications to the Atmospheric Chemistry on Jupiter

NASA Astrophysics Data System (ADS)

Keane, Thomas Christopher

1995-01-01

The existence of hydrogen cyanide (HCN) in the highly reducing atmosphere of Jupiter was a surprising discovery (Tokunaga et al., 1981). Previous studies that tested the theoretical proposal of Kaye and Strobel (1983a) that the HCN observed on Jupiter is the result of NH _3 photolysis in the presence of C _2H_2 established that acetonitrile (CH_3CN) and acetaldazine (CH _3CH=NN=CHCH_3) are important intermediates in HCN formation (Ferris and Ishikawa, 1988). In this study the rates of formation of these compounds, and of other recently detected intermediates, have been determined in static photolysis experiments at 296 K and at temperatures which are closer to those found in the Jovian atmosphere. Experiments were also performed, using a photochemical flow reactor, that allowed for a better approximation of the mixing ratios of reactant gases (8 times 10^{ -4} for NH_3 and 1 times 10^{-5} for C_2H_2) and the process of advection in the Jovian atmosphere. An overall reaction pathway for HCN formation is proposed. Major intermediates and products found in these laboratory simulations that have not yet been observed on Jupiter are acetonitrile (CH_3CN), acetaldazine (CH_3CH=NN=CHCH _3), acetaldehyde hydrazone (CH_3 CH=NNH_2), N-ethylethylideneimine (CH_3CH=NC_2H _5), ethylamine (C_2H _5NH_2) and methylamine (CH _3NH_2). HCN is formed by the photolysis of NH_3/C _2H_2 mixtures (40:5 torr) at 296 K and at low temperature (208 K, 195 K and 180 K) with the highest quantum efficiency for HCN formation observed at 180 K. In static experiments using a high partial pressure of H_2 the quantum yield for HCN formation decreased three-fold relative to the 296 K photolyses when no H_2 was used. An additional ten-fold decrease in the quantum yield for HCN formation occurred when using the flow system. The quantum yields for acetaldazine and acetaldehyde hydrazone formation were found to vary inversely to that for HCN formation. For those static experiments which best simulate Jovian reaction conditions (H_2: NH_3 : C_2H_2 = 600: 7.5: 5 torr, 180 K) the following products and their quantum yields for formation were obtained: C_2H_4 (0.129), CH_3 CH=NN=CHCH_3 (0.079), CH _3CH=NNH_2 (0.049), C_2H_5NH_2 (0.038), CH_3NH_2 (0.003), CH_3CN (0.002), HCN (0.001) and CH_3CH=NC _2H_5 (0.001).

CH3NH3PbI3 and CsPbI3 Supramolecular Clusters in 1D: Do They Evolve with the Same Principle of Cooperative Binding?

NASA Astrophysics Data System (ADS)

Varadwaj, Arpita; Varadwaj, Pradeep R.; Yamashita, Koichi

Development of novel semiconductor-based photo-catalytic and -voltaic systems is a major area of research in nanoscience and technologies, and engineering. The process can be either direct or indirect in converting the light energy into electricity. Some of the photovoltaics include the organic, dye-sensitized, and halide perovskite solar cells, among others. Methylammonium lead iodide (CH3NH3PbI3) inorganic-organic hybrid perovskite is one among the many highly valued semiconductors reported till date, comparable with the inorganic cesium lead iodide (CsPbI3) perovskite. These are competitive candidates in the solar energy race. Nevertheless, this study was concentrated on the fundamental understanding of the rational designs of the CH3NH3PbI3 and CsPbI3 supramolecular materials using first-principles calculations, emerged though the self-assembly of the respective building blocks. It therefore addresses the question whether the (CH3NH3PbI3)n and (CsPbI3)n (n =1-10) supramolecular clusters are the consequences of additivity, or non-additive cooperative binding? For addressing this question, the supramolecular properties such as the polarizability, the intermolecular charge transfer, and the binding energy, etc., all w.r.t the cluster size n, are exploited. CREST-JST, 7 Gobancho, Chiyoda-ku, Tokyo, Japan 102-0076.

Combination of Engineered Schwann Cell Grafts to Secrete Neurotrophin and Chondroitinase Promotes Axonal Regeneration and Locomotion after Spinal Cord Injury

PubMed Central

Pressman, Yelena; Moody, Alison; Berg, Randall; Muir, Elizabeth M.; Rogers, John H.; Ozawa, Hiroshi; Itoi, Eiji; Pearse, Damien D.; Bunge, Mary Bartlett

2014-01-01

Transplantation of Schwann cells (SCs) is a promising therapeutic strategy for spinal cord repair. SCs introduced into lesions support axon regeneration, but because these axons do not exit the transplant, additional approaches with SCs are needed. Here, we transplanted SCs genetically modified to secrete a bifunctional neurotrophin (D15A) and chondroitinase ABC (ChABC) into a subacute contusion injury in rats. We examined the effects of these modifications on graft volume, SC number, degradation of chondroitin sulfate proteoglycans (CSPGs), astrogliosis, SC myelination of axons, propriospinal and supraspinal axon numbers, locomotor outcome (BBB scoring, CatWalk gait analysis), and mechanical and thermal sensitivity on the hind paws. D15A secreted from transplanted SCs increased graft volume and SC number and myelinated axon number. SCs secreting ChABC significantly decreased CSPGs, led to some egress of SCs from the graft, and increased propriospinal and 5-HT-positive axons in the graft. SCs secreting both D15A and ChABC yielded the best responses: (1) the largest number of SC myelinated axons, (2) more propriospinal axons in the graft and host tissue around and caudal to it, (3) more corticospinal axons closer to the graft and around and caudal to it, (4) more brainstem neurons projecting caudal to the transplant, (5) increased 5-HT-positive axons in the graft and caudal to it, (6) significant improvement in aspects of locomotion, and (7) improvement in mechanical and thermal allodynia. This is the first evidence that the combination of SC transplants engineered to secrete neurotrophin and chondroitinase further improves axonal regeneration and locomotor and sensory function. PMID:24478364

GenoGAM: genome-wide generalized additive models for ChIP-Seq analysis.

PubMed

Stricker, Georg; Engelhardt, Alexander; Schulz, Daniel; Schmid, Matthias; Tresch, Achim; Gagneur, Julien

2017-08-01

Chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) is a widely used approach to study protein-DNA interactions. Often, the quantities of interest are the differential occupancies relative to controls, between genetic backgrounds, treatments, or combinations thereof. Current methods for differential occupancy of ChIP-Seq data rely however on binning or sliding window techniques, for which the choice of the window and bin sizes are subjective. Here, we present GenoGAM (Genome-wide Generalized Additive Model), which brings the well-established and flexible generalized additive models framework to genomic applications using a data parallelism strategy. We model ChIP-Seq read count frequencies as products of smooth functions along chromosomes. Smoothing parameters are objectively estimated from the data by cross-validation, eliminating ad hoc binning and windowing needed by current approaches. GenoGAM provides base-level and region-level significance testing for full factorial designs. Application to a ChIP-Seq dataset in yeast showed increased sensitivity over existing differential occupancy methods while controlling for type I error rate. By analyzing a set of DNA methylation data and illustrating an extension to a peak caller, we further demonstrate the potential of GenoGAM as a generic statistical modeling tool for genome-wide assays. Software is available from Bioconductor: https://www.bioconductor.org/packages/release/bioc/html/GenoGAM.html . gagneur@in.tum.de. Supplementary information is available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Carbon dioxide utilization via carbonate-promoted C-H carboxylation.

PubMed

Banerjee, Aanindeeta; Dick, Graham R; Yoshino, Tatsuhiko; Kanan, Matthew W

2016-03-10

Using carbon dioxide (CO2) as a feedstock for commodity synthesis is an attractive means of reducing greenhouse gas emissions and a possible stepping-stone towards renewable synthetic fuels. A major impediment to synthesizing compounds from CO2 is the difficulty of forming carbon-carbon (C-C) bonds efficiently: although CO2 reacts readily with carbon-centred nucleophiles, generating these intermediates requires high-energy reagents (such as highly reducing metals or strong organic bases), carbon-heteroatom bonds or relatively acidic carbon-hydrogen (C-H) bonds. These requirements negate the environmental benefit of using CO2 as a substrate and limit the chemistry to low-volume targets. Here we show that intermediate-temperature (200 to 350 degrees Celsius) molten salts containing caesium or potassium cations enable carbonate ions (CO3(2-)) to deprotonate very weakly acidic C-H bonds (pKa > 40), generating carbon-centred nucleophiles that react with CO2 to form carboxylates. To illustrate a potential application, we use C-H carboxylation followed by protonation to convert 2-furoic acid into furan-2,5-dicarboxylic acid (FDCA)--a highly desirable bio-based feedstock with numerous applications, including the synthesis of polyethylene furandicarboxylate (PEF), which is a potential large-scale substitute for petroleum-derived polyethylene terephthalate (PET). Since 2-furoic acid can readily be made from lignocellulose, CO3(2-)-promoted C-H carboxylation thus reveals a way to transform inedible biomass and CO2 into a valuable feedstock chemical. Our results provide a new strategy for using CO2 in the synthesis of multi-carbon compounds.

Carbon dioxide utilization via carbonate-promoted C-H carboxylation

NASA Astrophysics Data System (ADS)

Banerjee, Aanindeeta; Dick, Graham R.; Yoshino, Tatsuhiko; Kanan, Matthew W.

2016-03-01

Using carbon dioxide (CO2) as a feedstock for commodity synthesis is an attractive means of reducing greenhouse gas emissions and a possible stepping-stone towards renewable synthetic fuels. A major impediment to synthesizing compounds from CO2 is the difficulty of forming carbon-carbon (C-C) bonds efficiently: although CO2 reacts readily with carbon-centred nucleophiles, generating these intermediates requires high-energy reagents (such as highly reducing metals or strong organic bases), carbon-heteroatom bonds or relatively acidic carbon-hydrogen (C-H) bonds. These requirements negate the environmental benefit of using CO2 as a substrate and limit the chemistry to low-volume targets. Here we show that intermediate-temperature (200 to 350 degrees Celsius) molten salts containing caesium or potassium cations enable carbonate ions (CO32-) to deprotonate very weakly acidic C-H bonds (pKa > 40), generating carbon-centred nucleophiles that react with CO2 to form carboxylates. To illustrate a potential application, we use C-H carboxylation followed by protonation to convert 2-furoic acid into furan-2,5-dicarboxylic acid (FDCA)—a highly desirable bio-based feedstock with numerous applications, including the synthesis of polyethylene furandicarboxylate (PEF), which is a potential large-scale substitute for petroleum-derived polyethylene terephthalate (PET). Since 2-furoic acid can readily be made from lignocellulose, CO32--promoted C-H carboxylation thus reveals a way to transform inedible biomass and CO2 into a valuable feedstock chemical. Our results provide a new strategy for using CO2 in the synthesis of multi-carbon compounds.

JPRS Report, Science & Technology, Japan, 1987 S&T Paper

DTIC Science & Technology

1988-08-26

council recommended in its report increasing the amount of subsidies for scientific research, vitalizing the scientific research systems at...activities that have recently been progressing in Japan. Greatest importance was attached to "the development of an effective means of preventing cancer...natter COKPENDEX (Engineering —Civil enginsering, environmental eng, —Hetal, resource eng —Hechanical eng. —ChBnical, agric . eng —Agricultural, nana

Jeffrey A. Christians | NREL

Science.gov Websites

. In 2015, the University of Notre Dame College of Engineering awarded him with the Eli J. and Helen Featured Publications Schelhas, L. T.; Christians, J. A.; Berry, J. J.; Toney, M. F.; Tassone, C. J .; Luther, J. M.; Stone, K. H. "Monitoring a Silent Phase Transition in CH3NH3PbI3 Solar Cells via

Mechanical Computing in Microelectromechanical Systems (MEMS)

DTIC Science & Technology

2003-03-01

New York: John Wiley and Sons, Inc., 1968. 25. Helvajian , H . and S. Janson, Microengineering Aerospace Systems, ch. Micro- engineering Space Systems...sacrificial layer. (g)Strip remaining resist. ( h ) Deposit a structural layer(conformal deposition is shown). (i) Deposit resist. (j) Expose resist...layer is then deposited, and assuming a conformal process, the structural layer will follow the topography of the sacrificial layer (Figure 2.9( h

Limitations and possibilities of low cell number ChIP-seq

PubMed Central

2012-01-01

Background Chromatin immunoprecipitation coupled with high-throughput DNA sequencing (ChIP-seq) offers high resolution, genome-wide analysis of DNA-protein interactions. However, current standard methods require abundant starting material in the range of 1–20 million cells per immunoprecipitation, and remain a bottleneck to the acquisition of biologically relevant epigenetic data. Using a ChIP-seq protocol optimised for low cell numbers (down to 100,000 cells / IP), we examined the performance of the ChIP-seq technique on a series of decreasing cell numbers. Results We present an enhanced native ChIP-seq method tailored to low cell numbers that represents a 200-fold reduction in input requirements over existing protocols. The protocol was tested over a range of starting cell numbers covering three orders of magnitude, enabling determination of the lower limit of the technique. At low input cell numbers, increased levels of unmapped and duplicate reads reduce the number of unique reads generated, and can drive up sequencing costs and affect sensitivity if ChIP is attempted from too few cells. Conclusions The optimised method presented here considerably reduces the input requirements for performing native ChIP-seq. It extends the applicability of the technique to isolated primary cells and rare cell populations (e.g. biobank samples, stem cells), and in many cases will alleviate the need for cell culture and any associated alteration of epigenetic marks. However, this study highlights a challenge inherent to ChIP-seq from low cell numbers: as cell input numbers fall, levels of unmapped sequence reads and PCR-generated duplicate reads rise. We discuss a number of solutions to overcome the effects of reducing cell number that may aid further improvements to ChIP performance. PMID:23171294

Improvement in hemocompatibility of chitosan/soy protein composite membranes by heparinization.

PubMed

Wang, Xiaomei; Shi, Na; Chen, Yan; Li, Chen; Du, Xinshen; Jin, Weihua; Chen, Yun; Chang, Peter R

2012-01-01

To improve the hemocompatibility of chitosan/soy protein isolate composite membranes by heparinization. Chitosan/soy protein isolate membranes (ChS-n, n=0, 10 and 30, corresponding to the soy protein isolate content in the membranes) and heparinized ChS-n membranes (HChS-n) were prepared by blending in dilute HAc/NaAc solution. The hemocompatibility of ChS-n and HChS-n membranes were comparatively evaluated by measuring surface heparin density, blood platelet adhesion, plasma recalcification time (PRT), thrombus formation and hemolysis assay. The surface heparin density analysis showed that heparinized chitosan/SPI soy protein isolate membranes have been successfully prepared by blending. The density of heparin on the surface of HChS-n membranes was in the range of 0.67-1.29 μg/cm2. The results of platelet adhesion measurement showed that the platelet adhesion numbers of HChS-n membranes were lower than those of the corresponding ChS-n membranes. The PRT of the HChS-0, HChS-10 and HChS-30 membranes were around 292, 306 and 295 s, respectively, which were longer than the corresponding ChS-0 (152 s), ChS-10 (204 s) and ChS-30 (273 s) membranes. The hemolysis rate of HChS-n membranes was lower than 1%. The hemocompatibility of ChS membranes could be improved by blending with heparin. Compared with ChS membranes, HChS membranes showed lower platelet adhesion, longer PRT, higher BCI, significant thromboresistivity and a lower hemolysis rate due to the heparinization. This widens the application of chitosan and soy protein-based biomaterials that may come in contact with blood.

Biogeochemical controls on microbial CH4 and CO2 production in Arctic polygon tundra

NASA Astrophysics Data System (ADS)

Zheng, J.

2016-12-01

Accurately simulating methane (CH4) and carbon dioxide (CO2) emissions from high latitude soils is critically important for reducing uncertainties in soil carbon-climate feedback predictions. The signature polygonal ground of Arctic tundra generates high level of heterogeneity in soil thermal regime, hydrology and oxygen availability, which limits the application of current land surface models with simple moisture response functions. We synthesized CH4 and CO2 production measurements from soil microcosm experiments across a wet-to dry permafrost degradation gradient from low-centered (LCP) to flat-centered (FCP), and high-centered polygons (HCP) to evaluate the relative importance of biogeochemical processes and their response to warming. More degraded polygon (HCP) showed much less carbon loss as CO2 or CH4, while the total CO2 production from FCP is comparable to that from LCP. Maximum CH4 production from the active layer of LCP was nearly 10 times that of permafrost and FCP. Multivariate analyses identifies gravimetric water content and organic carbon content as key predictors for CH4 production, and iron reduction as a key regulator of pH. The synthesized data are used to validate the geochemical model PHREEQC with extended anaerobic organic substrate turnover, fermentation, iron reduction, and methanogenesis reactions. Sensitivity analyses demonstrate that better representations of anaerobic processes and their pH dependency could significantly improve estimates of CH4 and CO2 production. The synthesized data suggest local decreases in CH4 production along the polygon degradation gradient, which is consistent with previous surface flux measurements. Methane oxidation occurring through the soil column of degraded polygons contributes to their low CH4 emissions as well.

Selective CO Production by Photoelectrochemical Methane Oxidation on TiO2.

PubMed

Li, Wei; He, Da; Hu, Guoxiang; Li, Xiang; Banerjee, Gourab; Li, Jingyi; Lee, Shin Hee; Dong, Qi; Gao, Tianyue; Brudvig, Gary W; Waegele, Matthias M; Jiang, De-En; Wang, Dunwei

2018-05-23

The inertness of the C-H bond in CH 4 poses significant challenges to selective CH 4 oxidation, which often proceeds all the way to CO 2 once activated. Selective oxidation of CH 4 to high-value industrial chemicals such as CO or CH 3 OH remains a challenge. Presently, the main methods to activate CH 4 oxidation include thermochemical, electrochemical, and photocatalytic reactions. Of them, photocatalytic reactions hold great promise for practical applications but have been poorly studied. Existing demonstrations of photocatalytic CH 4 oxidation exhibit limited control over the product selectivity, with CO 2 as the most common product. The yield of CO or other hydrocarbons is too low to be of any practical value. In this work, we show that highly selective production of CO by CH 4 oxidation can be achieved by a photoelectrochemical (PEC) approach. Under our experimental conditions, the highest yield for CO production was 81.9%. The substrate we used was TiO 2 grown by atomic layer deposition (ALD), which features high concentrations of Ti 3+ species. The selectivity toward CO was found to be highly sensitive to the substrate types, with significantly lower yield on P25 or commercial anatase TiO 2 substrates. Moreover, our results revealed that the selectivity toward CO also depends on the applied potentials. Based on the experimental results, we proposed a reaction mechanism that involves synergistic effects by adjacent Ti sites on TiO 2 . Spectroscopic characterization and computational studies provide critical evidence to support the mechanism. Furthermore, the synergistic effect was found to parallel heterogeneous CO 2 reduction mechanisms. Our results not only present a new route to selective CH 4 oxidation, but also highlight the importance of mechanistic understandings in advancing heterogeneous catalysis.

Microchip-Based Organophosphorus Detection Using Bienzyme Bioelectrocatalysis

NASA Astrophysics Data System (ADS)

Han, Yong Duk; Jeong, Chi Yong; Lee, Jun Hee; Lee, Dae-Sik; Yoon, Hyun C.

2012-06-01

We have developed a microsystem for the detection of organophosphorus (OP) compounds using acetylcholine esterase (AchE) and choline oxidase (ChOx) bienzyme bioelectrocatalysis. Because AchE is irreversibly inhibited by OP pesticides, the change in AchE activity with OP treatment can be traced to determine OP concentration. Polymer-associated ChOx immobilization on the working electrode surface and magnetic microparticle (MP)-assisted AchE deposition methods were employed to create an AchE-ChOx bienzyme-modified biosensing system. ChOx was immobilized on the micropatterned electrodes using poly(L-lysine), glutaraldehyde, and amine-rich interfacial surface. AchE was immobilized on the MP surface via Schiff's base formation, and the enzyme-modified MPs were deposited on the working electrode using a magnet under the microfluidic channel. The bioelectrocatalytic reaction between AchE-ChOx bienzyme cascade and the ferrocenyl electron shuttle was successfully used to detect OP with the developed microchip. This provides a self-contained and relatively easy method for OP detection. It requires minimal time and a small sample size, and has potential analytic applications in pesticides and chemical warfare agents.

Dynamics starting at a conical intersection: Application to the photochemistry of pyrrole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sellner, Bernhard; Barbatti, Mario; Lischka, Hans

The photochemical ring opening process in pyrrole has been investigated by performing classical on-the-fly dynamics using the multiconfiguration self-consistent field method for the computation of energies and energy gradients. As starting point for the dynamics the conical intersection corresponding to the ring-puckered ring-opened structure, determined previously [Barbatti et al., J. Chem. Phys. 125, 164323 (2006)], has been chosen. Two sets of initial conditions for the nuclear velocities were constructed: (i) nuclear velocities in the branching (g,h) plane of the conical intersection and (ii) statistical distribution for all atoms. Both sets of initial conditions show very similar results. Reactive trajectories aremore » only found in a very limited sector in the (g,h) plane and reaction products are very similar. Within the simulation time of 1 ps, ring opening of pyrrole to the biradical NH=CH-CH-CH=CH chain followed by ring closure to a substituted cyclopropene structure (NH=CH-C{sub 3}H{sub 3}) is observed. The computed structural data correlate well with the experimentally observed dissociation products.« less

Bioorthogonal Diversification of Peptides through Selective Ruthenium(II)-Catalyzed C-H Activation.

PubMed

Schischko, Alexandra; Ren, Hongjun; Kaplaneris, Nikolaos; Ackermann, Lutz

2017-02-01

Methods for the chemoselective modification of amino acids and peptides are powerful techniques in biomolecular chemistry. Among other applications, they enable the total synthesis of artificial peptides. In recent years, significant momentum has been gained by exploiting palladium-catalyzed cross-coupling for peptide modification. Despite major advances, the prefunctionalization elements on the coupling partners translate into undesired byproduct formation and lengthy synthetic operations. In sharp contrast, we herein illustrate the unprecedented use of versatile ruthenium(II)carboxylate catalysis for the step-economical late-stage diversification of α- and β-amino acids, as well as peptides, through chemo-selective C-H arylation under racemization-free reaction conditions. The ligand-accelerated C-H activation strategy proved water-tolerant and set the stage for direct fluorescence labelling as well as various modes of peptide ligation with excellent levels of positional selectivity in a bioorthogonal fashion. The synthetic utility of our approach is further demonstrated by twofold C-H arylations for the complexity-increasing assembly of artificial peptides within a multicatalytic C-H activation manifold. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

F -state quenching with CH 4 for buffer-gas cooled 171 Y b + frequency standard [Methane (CH4) for quenching the F-state in trapped Yb+ ions].

DOE PAGES

Jau, Y. -Y.; Hunker, J. D.; Schwindt, P. D. D.

2015-11-01

We report that methane, CH 4, can be used as an efficient F-state quenching gas for trapped ytterbium ions. The quenching rate coefficient is measured to be (2.8 ± 0.3) × 10 6 s -1 Torr -1. For applications that use microwave hyperfine transitions of the ground-state 171Y b ions, the CH4 induced frequency shift coefficient and the decoherence rate coefficient are measured as δν/ν = (-3.6 ± 0.1) × 10 -6 Torr -1 and 1/T2 = (1.5 ± 0.2) × 10 5 s -1 Torr -1. In our buffer-gas cooled 171Y b+ microwave clock system, we find that onlymore » ≤10 -8 Torr of CH 4 is required under normal operating conditions to efficiently clear the F-state and maintain ≥85% of trapped ions in the ground state with insignificant pressure shift and collisional decoherence of the clock resonance.« less

iASeq: integrative analysis of allele-specificity of protein-DNA interactions in multiple ChIP-seq datasets

PubMed Central

2012-01-01

Background ChIP-seq provides new opportunities to study allele-specific protein-DNA binding (ASB). However, detecting allelic imbalance from a single ChIP-seq dataset often has low statistical power since only sequence reads mapped to heterozygote SNPs are informative for discriminating two alleles. Results We develop a new method iASeq to address this issue by jointly analyzing multiple ChIP-seq datasets. iASeq uses a Bayesian hierarchical mixture model to learn correlation patterns of allele-specificity among multiple proteins. Using the discovered correlation patterns, the model allows one to borrow information across datasets to improve detection of allelic imbalance. Application of iASeq to 77 ChIP-seq samples from 40 ENCODE datasets and 1 genomic DNA sample in GM12878 cells reveals that allele-specificity of multiple proteins are highly correlated, and demonstrates the ability of iASeq to improve allelic inference compared to analyzing each individual dataset separately. Conclusions iASeq illustrates the value of integrating multiple datasets in the allele-specificity inference and offers a new tool to better analyze ASB. PMID:23194258

40 CFR 1068.31 - What provisions apply to nonroad or stationary engines that change their status?

Code of Federal Regulations, 2010 CFR

2010-07-01

... nonroad application is subsequently used in an application other than a nonroad application, or when an engine previously used in a stationary application (i.e., an engine that was not used as a nonroad engine... stationary engine becomes a new nonroad engine if— (1) It is used in an application that meets the criteria...

Chiral effective theory methods and their application to the structure of hadrons from lattice QCD

NASA Astrophysics Data System (ADS)

Shanahan, P. E.

2016-12-01

For many years chiral effective theory (ChEFT) has enabled and supported lattice QCD calculations of hadron observables by allowing systematic effects from unphysical lattice parameters to be controlled. In the modern era of precision lattice simulations approaching the physical point, ChEFT techniques remain valuable tools. In this review we discuss the modern uses of ChEFT applied to lattice studies of hadron structure in the context of recent determinations of important and topical quantities. We consider muon g-2, strangeness in the nucleon, the proton radius, nucleon polarizabilities, and sigma terms relevant to the prediction of dark-matter-hadron interaction cross-sections, among others.

Ir catalysts: Preventing CH3COOH formation in ethanol oxidation

NASA Astrophysics Data System (ADS)

Miao, Bei; Wu, Zhipeng; Xu, Han; Zhang, Minhua; Chen, Yifei; Wang, Lichang

2017-11-01

Current catalysts used for ethanol oxidation reaction (EOR) cannot effectively prevent CH3COOH formation, and thus become a major hindrance for direct ethanol fuel cell applications. We report an Ir catalyst that shows great promise for a complete EOR based on density functional theory calculations using PBE functional. The reaction barrier on Ir(1 0 0) was found to be 2.10 eV for CH3COOH formation, which is much higher than currently used Pd and Pt, and 0.57 eV for Csbnd C bond cleavage in CHCO species, which are comparable to Pd and Pt. The result suggests future directions for studying optimal complete EOR catalysts.

Palladium-catalyzed cyclocoupling of 2-halobiaryls with isocyanides via the cleavage of carbon-hydrogen bonds.

PubMed

Tobisu, Mamoru; Imoto, Shinya; Ito, Sana; Chatani, Naoto

2010-07-16

To demonstrate the utility of isocyanides in catalytic C-H bond functionalization reactions, a palladium-catalyzed cyclocoupling reaction of 2-halobiaryls with isocyanides was developed. The reaction afforded an array of fluorenone imine derivatives via the cleavage of a C-H bond at the 2'-position of 2-halobiaryls. The use of 2,6-disubstituted phenyl isocyanide was crucial for this catalytic cyclocoupling reaction to proceed. The reaction was applicable to heterocyclic and vinylic substrates, allowing the construction of a wide range of ring system. The large kinetic isotope effect observed (k(H)/k(D) = 5.3) indicates that C-H bond activation was the turnover-limiting step in this catalysis.

Shift in Chemical Potential of Superconducting Bi2212 Measured by Ultrafast Photoemission Spectroscopy

NASA Astrophysics Data System (ADS)

Miller, Tristan; Smallwood, Chris; Zhang, Wentao; Eisaki, Hiroshi; Lee, Dung-Hai; Lanzara, Alessandra

2015-03-01

Time- and Angle-resolved photoemission spectroscopy (tr-ARPES) has been used to directly measure the dynamics of many different properties of high-temperature superconductors, including the quasiparticle relaxation, cooper pair recombination, and many-body interactions. There have also been several intriguing results on several materials showing how laser pulses can manipulate their chemical potential on ultrafast timescales, and it's been suggested that these effects could find applications in optoelectronic devices. Studies on GaAs have also found that laser pulses may induce a surface voltage effect. Here, we extend these studies for the first time to a Bi2212 sample in the superconducting state, and disentangle the shift in chemical potential from surface voltage effects. This work was supported by Berkeley Lab's program on Quantum Materials, funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract No. DE-AC02-05CH11231.

Amplitude modulation of alpha-band rhythm caused by mimic collision: MEG study.

PubMed

Yokosawa, Koichi; Watanabe, Tatsuya; Kikuzawa, Daichi; Aoyama, Gakuto; Takahashi, Makoto; Kuriki, Shinya

2013-01-01

Detection of a collision risk and avoiding the collision are important for survival. We have been investigating neural responses when humans anticipate a collision or intend to take evasive action by applying collision-simulating images in a predictable manner. Collision-simulating images and control images were presented in random order to 9 healthy male volunteers. A cue signal was also given visually two seconds before each stimulus to enable each participant to anticipate the upcoming stimulus. Magnetoencephalograms (MEG) were recorded with a 76-ch helmet system. The amplitude of alpha band (8-13 Hz) rhythm when anticipating the upcoming collision-simulating image was significantly smaller than that when anticipating control images even just after the cue signal. This result demonstrates that anticipating a negative (dangerous) event induced event-related desynchronization (ERD) of alpha band activity, probably caused by attention. The results suggest the feasibility of detecting endogenous brain activities by monitoring alpha band rhythm and its possible applications to engineering systems, such as an automatic collision evasion system for automobiles.

Spatial organization of heterologous metabolic system in vivo based on TALE.

PubMed

Zhu, Lv-yun; Qiu, Xin-Yuan; Zhu, Ling-Yun; Wu, Xiao-Min; Zhang, Yuan; Zhu, Qian-Hui; Fan, Dong-Yu; Zhu, Chu-Shu; Zhang, Dong-Yi

2016-05-17

For years, prokaryotic hosts have been widely applied in bio-engineering. However, the confined in vivo enzyme clustering of heterologous metabolic pathways in these organisms often results in low local concentrations of enzymes and substrates, leading to a low productive efficacy. We developed a new method to accelerate a heterologous metabolic system by integrating a transcription activator-like effector (TALE)-based scaffold system into an Escherichia coli chassis. The binding abilities of the TALEs to the artificial DNA scaffold were measured through ChIP-PCR. The effect of the system was determined through a split GFP study and validated through the heterologous production of indole-3-acetic acid (IAA) by incorporating TALE-fused IAA biosynthetic enzymes in E. coli. To the best of our knowledge, we are the first to use the TALE system as a scaffold for the spatial organization of bacterial metabolism. This technique might be used to establish multi-enzymatic reaction programs in a prokaryotic chassis for various applications.

Application of histone modification-specific interaction domains as an alternative to antibodies.

PubMed

Kungulovski, Goran; Kycia, Ina; Tamas, Raluca; Jurkowska, Renata Z; Kudithipudi, Srikanth; Henry, Chisato; Reinhardt, Richard; Labhart, Paul; Jeltsch, Albert

2014-11-01

Post-translational modifications (PTMs) of histones constitute a major chromatin indexing mechanism, and their proper characterization is of highest biological importance. So far, PTM-specific antibodies have been the standard reagent for studying histone PTMs despite caveats such as lot-to-lot variability of specificity and binding affinity. Herein, we successfully employed naturally occurring and engineered histone modification interacting domains for detection and identification of histone PTMs and ChIP-like enrichment of different types of chromatin. Our results demonstrate that histone interacting domains are robust and highly specific reagents that can replace or complement histone modification antibodies. These domains can be produced recombinantly in Escherichia coli at low cost and constant quality. Protein design of reading domains allows for generation of novel specificities, addition of affinity tags, and preparation of PTM binding pocket variants as matching negative controls, which is not possible with antibodies. © 2014 Kungulovski et al.; Published by Cold Spring Harbor Laboratory Press.

CO2-based hydrogen storage - Hydrogen generation from formaldehyde/water

NASA Astrophysics Data System (ADS)

Trincado, Monica; Grützmacher, Hansjörg; Prechtl, Martin H. G.

2018-04-01

Formaldehyde (CH2O) is the simplest and most significant industrially produced aldehyde. The global demand is about 30 megatons annually. Industrially it is produced by oxidation of methanol under energy intensive conditions. More recently, new fields of application for the use of formaldehyde and its derivatives as, i.e. cross-linker for resins or disinfectant, have been suggested. Dialkoxymethane has been envisioned as a combustion fuel for conventional engines or aqueous formaldehyde and paraformaldehyde may act as a liquid organic hydrogen carrier molecule (LOHC) for hydrogen generation to be used for hydrogen fuel cells. For the realization of these processes, it requires less energy-intensive technologies for the synthesis of formaldehyde. This overview summarizes the recent developments in low-temperature reductive synthesis of formaldehyde and its derivatives and low-temperature formaldehyde reforming. These aspects are important for the future demands on modern societies' energy management, in the form of a methanol and hydrogen economy, and the required formaldehyde feedstock for the manufacture of many formaldehyde-based daily products.