1,841 research outputs found
Feasibility study of a humidity control and oxygen supply system utilizing a water vapor electrolysis unit
Design and tests of water vapor electrolysis cell for generating and regulating spacecraft oxygen and for controlling humidit
One man electrochemical air revitalization system
An integrated water vapor electrolysis (WVE) hydrogen depolarized CO2 concentrator (HDC) system sized for one man support over a wide range of inlet air conditions was designed, fabricated, and tested. Data obtained during 110 days of testing verified that this system can provide the necessary oxygen, CO2 removal, and partial humidity control to support one man (without exceeding a cabin partial pressure of 3.0 mmHg for CO2 and while maintaining a 20% oxygen level), when operated at a WVE current of 50 amperes and an HDC current of 18 amperes. An evaluation to determine the physical properties of tetramethylammonium bicarbonate (TMAC) and hydroxide was made. This provides the necessary electrolyte information for designing an HDC cell using TMAC
Hydrogen depolarized carbon dioxide concentrator performance improvements and cell pair structural tests
The investigations and testing associated with the CO2 removal efficiency and voltage degradation of a hydrogen depolarized carbon oxide concentrator are reported. Also discussed is the vibration testing of a water vapor electrolysis cell pair. Performance testing of various HDC cell pairs with Cs2CO3 electrolyte provided sufficient parametric and endurance data to size a six man space station prototype CO2 removal system as having 36 HDC cell pairs, and to verify a life capability exceeding six moths. Testing also demonstrated that tetramethylammonium carbonate is an acceptable HDC electrolyte for operating over the relative humidity range of 30 to 90 percent and over a temperature range of 50 to 80 F
Reductive CâC Coupling from α,ÎČâUnsaturated Nitriles by Intercepting Keteniminates
We present an atomâeconomic strategy to catalytically generate and intercept nitrile anion equivalents using hydrogen transfer catalysis. Addition of α,ÎČâunsaturated nitriles to a pincerâbased RuâH complex affords structurally characterized ÎșâNâcoordinated keteniminates by selective 1,4âhydride transfer. When generated inâ
situ under catalytic hydrogenation conditions, electrophilic addition to the keteniminate was achieved using anhydrides to provide αâcyanoacetates in high yields. This work represents a new application of hydrogen transfer catalysis using α,ÎČâunsaturated nitriles for reductive CâC coupling reactions.An atomâeconomic strategy to catalytically generate and intercept nitrile anion equivalents by hydrogen transfer catalysis has been developed. Addition of α,ÎČâunsaturated nitriles to a pincerâbased RuâH complex affords keteniminates by selective 1,4âhydride transfer, which were employed in a net hydrogenative acylation reaction.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149503/1/anie201904530.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149503/2/anie201904530-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149503/3/anie201904530_am.pd
Physicochemical characterization of the PEG8000-Na2SO4 aqueous two-phase system
The polyethylene glycol-sodium sulfate aqueous two-phase system has been characterized at 23 °C. Tielines
for the phase diagram were obtained experimentally. Phases in equilibrium were characterized by means
of the solvatochromic parameters Ï*, α, and ÎČ, which provide a measurement of the polarity/polarizability
and the H-bond donor and acceptor abilities, respectively. The ability of the phases to participate in hydrophobic
interactions was characterized by means of the free energy of transfer of a methylene group between the
conjugated phases, using the partition of a homologous series of dinitrophenylated amino acids. The results
show the effect of the presence of polymer and salt in the aqueous phase, and a comparison of both phases
with pure water is made.LSRE-PortoUniversidade CatĂłlica PortuguesaEscola Superior de Biotecnologia do PortoFundação para a CiĂȘncia e a Tecnologia (FCT
Practical aspects of the automated preparation of aqueous two phase systems for the analysis of biological macromolecules
Sampling Local Fungal Diversity in an Undergraduate Laboratory using DNA Barcoding
Traditional methods for fungal species identification require diagnostic morphological characters and are often limited by the availability of fresh fruiting bodies and local identification resources. DNA barcoding offers an additional method of species identification and is rapidly developing as a critical tool in fungal taxonomy. As an exercise in an undergraduate biology course, we identified 9 specimens collected from the Hendrix College campus in Conway, Arkansas, USA to the genus or species level using morphology. We report that DNA barcoding targeting the internal transcribed spacer (ITS) region supported several of our taxonomic determinations and we were able to contribute 5 ITS sequences to GenBank that were supported by vouchered collection information. We suggest that small-scale barcoding projects are possible and that they have value for documenting fungal diversity
Rapid and inexpensive purification of adenovirus vectors using an optimised aqueous two-phase technology.
Adenoviruses (AdVs) are used as gene therapy vectors to treat human diseases and as vaccines against COVID-19. AdVs are produced by transfecting human embryonic kidney 239 (HEK293) or PER.C6 virus producer cells with AdV plasmid vectors or infecting these cells withcell lysates containing replication-defective AdV. Cell lysates can be purified further by caesium chloride or chromatographic protocols to research virus seed stocks (RVSS) for characterisation to high quality master virus seed stocks (MVSS) and working virus seed stocks (WVSS) before downstream production of pure, high titre AdV. Lysates are poorly infectious, block filtration columns and have limited storage capability. Aqueous two-phase systems (ATPS) are an alternative method for AdV purification that rapidly generates cleaner RVSS for characterisation to MVSS. After testing multiple ATPS formulations, an aqueous mixture of 20 % PEG 600 and 20 % (NH4)2SO4 (w/w) was found most effective for AdV partitioning, producing up to 97+3% yield of high-titre virus that was devoid of aggregates both effective in vitro and in vivo with no observable cytotoxicity. Importantly, AdV preparations stored at â20 °C or 4 °C show negligible loss of titre and are suitable for downstream processing to clinical grade to support the need for AdV vaccines
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Economic impacts of the United States of siting decisions for the international thermonuclear experimental reactor: Executive summary
This summary highlights the results of a study that examined and compared the probable short-term economic impacts of the International Thermonuclear Experimental Reactor (ITER) on the United States (U.S.) if (1) ITER were to be sited in the U.S. or (2) ITER were to be sited in one of the other countries that, along with the U.S., are currently participating in the ITER program. Life-cycle costs associated with ITER construction, operation, and decommissioning were analyzed to assess their economic impact. A number of possible U.S. {open_quotes}host{close_quotes} and U.S. {open_quotes}non-host{close_quotes} technology and cost-sharing arrangements were examined. The study examined both national and local/regional economic impacts, as measured by gross domestic product (GDP), regional output, employment, income, and net exports. These impacts represent a portion of the complex, interrelated set of economic considerations that characterize U.S. host and U.S. non-host participation in ITER
Quasi-classical Lie algebras and their contractions
After classifying indecomposable quasi-classical Lie algebras in low
dimension, and showing the existence of non-reductive stable quasi-classical
Lie algebras, we focus on the problem of obtaining sufficient conditions for a
quasi-classical Lie algebras to be the contraction of another quasi-classical
algebra. It is illustrated how this allows to recover the Yang-Mills equations
of a contraction by a limiting process, and how the contractions of an algebra
may generate a parameterized families of Lagrangians for pairwise
non-isomorphic Lie algebras.Comment: 17 pages, 2 Table
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