Utilization of xylose as a carbon source for mixotrophic growth of Scenedesmus obliquus.

PubMed

Yang, Suling; Liu, Guijun; Meng, Youting; Wang, Ping; Zhou, Sijing; Shang, Hongzhong

2014-11-01

Mixotrophic cultivation is one potential mode for microalgae production, and an economically acceptable and environmentally sustainable organic carbon source is essential. The potential use of xylose for culturing Scenedesmus obliquus in a mixotrophic mode and physiological features of xylose-grown S. obliquus were studied. S. obliquus had a certain xylose tolerance, and was capable of utilizing xylose for growth. At a xylose concentration of 4gL(-1), the maximal cell density was 2.2gL(-1), being 2.9-fold of that under photoautotrophic condition and arriving to the level of mixotrophic growth using 4gL(-1) glucose. No changes in cellular morphology of the cells grown with or without xylose were detected. Fluorescence emission from photosystem II (PS II) relative to photosystem I (PS I) was decreased in mixotrophic cells, implying that the PSII activity was decreased. The biomass lipid content was enhanced and carbohydrate concentration was decreased, in relation to photoautotrophic controls. Copyright © 2014 Elsevier Ltd. All rights reserved.

Carbon Dioxide to Methanol: The Aqueous Catalytic Way at Room Temperature.

PubMed

Sordakis, Katerina; Tsurusaki, Akihiro; Iguchi, Masayuki; Kawanami, Hajime; Himeda, Yuichiro; Laurenczy, Gábor

2016-10-24

Carbon dioxide may constitute a source of chemicals and fuels if efficient and renewable processes are developed that directly utilize it as feedstock. Two of its reduction products are formic acid and methanol, which have also been proposed as liquid organic chemical carriers in sustainable hydrogen storage. Here we report that both the hydrogenation of carbon dioxide to formic acid and the disproportionation of formic acid into methanol can be realized at ambient temperature and in aqueous, acidic solution, with an iridium catalyst. The formic acid yield is maximized in water without additives, while acidification results in complete (98 %) and selective (96 %) formic acid disproportionation into methanol. These promising features in combination with the low reaction temperatures and the absence of organic solvents and additives are relevant for a sustainable hydrogen/methanol economy. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wabash Valley Integrated Gasification Combined Cycle, Coal to Fischer Tropsch Jet Fuel Conversion Study

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

Shah, Jayesh; Hess, Fernando; Horzen, Wessel van

This reports examines the feasibility of converting the existing Wabash Integrated Gasification Combined Cycle (IGCC) plant into a liquid fuel facility, with the goal of maximizing jet fuel production. The fuels produced are required to be in compliance with Section 526 of the Energy Independence and Security Act of 2007 (EISA 2007 §526) lifecycle greenhouse gas (GHG) emissions requirements, so lifecycle GHG emissions from the fuel must be equal to or better than conventional fuels. Retrofitting an existing gasification facility reduces the technical risk and capital costs associated with a coal to liquids project, leading to a higher probability ofmore » implementation and more competitive liquid fuel prices. The existing combustion turbine will continue to operate on low cost natural gas and low carbon fuel gas from the gasification facility. The gasification technology utilized at Wabash is the E-Gas™ Technology and has been in commercial operation since 1995. In order to minimize capital costs, the study maximizes reuse of existing equipment with minimal modifications. Plant data and process models were used to develop process data for downstream units. Process modeling was utilized for the syngas conditioning, acid gas removal, CO 2 compression and utility units. Syngas conversion to Fischer Tropsch (FT) liquids and upgrading of the liquids was modeled and designed by Johnson Matthey Davy Technologies (JM Davy). In order to maintain the GHG emission profile below that of conventional fuels, the CO 2 from the process must be captured and exported for sequestration or enhanced oil recovery. In addition the power utilized for the plant’s auxiliary loads had to be supplied by a low carbon fuel source. Since the process produces a fuel gas with sufficient energy content to power the plant’s loads, this fuel gas was converted to hydrogen and exported to the existing gas turbine for low carbon power production. Utilizing low carbon fuel gas and process steam in the existing combined cycle power plant provides sufficient power for all plant loads. The lifecycle GHG profile of the produced jet fuel is 95% of conventional jet fuel. Without converting the fuel gas to a low carbon fuel gas, the emissions would be 108% of conventional jet fuel and without any GHG mitigation, the profile would be 206%. Oil prices greater than $120 per barrel are required to reach a targeted internal rate of return on equity (IRROE) of 12%. Although capital expenditure is much less than if a greenfield facility was built, the relatively small size of the plant, assumed coal price, and the CTL risk profile used in the economic assumptions lead to a high cost of production. Assuming more favorable factors, the economic oil price could be reduced to $78 per barrel with GHG mitigation and $55 per barrel with no GHG mitigation.« less

Designing overall stoichiometric conversions and intervening metabolic reactions

DOE PAGES

Chowdhury, Anupam; Maranas, Costas D.

2015-11-04

Existing computational tools for de novo metabolic pathway assembly, either based on mixed integer linear programming techniques or graph-search applications, generally only find linear pathways connecting the source to the target metabolite. The overall stoichiometry of conversion along with alternate co-reactant (or co-product) combinations is not part of the pathway design. Therefore, global carbon and energy efficiency is in essence fixed with no opportunities to identify more efficient routes for recycling carbon flux closer to the thermodynamic limit. Here, we introduce a two-stage computational procedure that both identifies the optimum overall stoichiometry (i.e., optStoic) and selects for (non-)native reactions (i.e.,more » minRxn/minFlux) that maximize carbon, energy or price efficiency while satisfying thermodynamic feasibility requirements. Implementation for recent pathway design studies identified non-intuitive designs with improved efficiencies. Specifically, multiple alternatives for non-oxidative glycolysis are generated and non-intuitive ways of co-utilizing carbon dioxide with methanol are revealed for the production of C 2+ metabolites with higher carbon efficiency.« less

Activated Carbon Fibers with Hierarchical Nanostructure Derived from Waste Cotton Gloves as High-Performance Electrodes for Supercapacitors.

PubMed

Wei, Chao; Yu, Jianlin; Yang, Xiaoqing; Zhang, Guoqing

2017-12-01

One of the most challenging issues that restrict the biomass/waste-based nanocarbons in supercapacitor application is the poor structural inheritability during the activating process. Herein, we prepare a class of activated carbon fibers by carefully selecting waste cotton glove (CG) as the precursor, which mainly consists of cellulose fibers that can be transformed to carbon along with good inheritability of their fiber morphology upon activation. As prepared, the CG-based activated carbon fiber (CGACF) demonstrates a surface area of 1435 m 2  g -1 contributed by micropores of 1.3 nm and small mesopores of 2.7 nm, while the fiber morphology can be well inherited from the CG with 3D interconnected frameworks created on the fiber surface. This hierarchically porous structure and well-retained fiber-like skeleton can simultaneously minimize the diffusion/transfer resistance of the electrolyte and electron, respectively, and maximize the surface area utilization for charge accumulation. Consequently, CGACF presents a higher specific capacitance of 218 F g -1 and an excellent high-rate performance as compared to commercial activated carbon.

Optimal Energy Management for a Smart Grid using Resource-Aware Utility Maximization

NASA Astrophysics Data System (ADS)

Abegaz, Brook W.; Mahajan, Satish M.; Negeri, Ebisa O.

2016-06-01

Heterogeneous energy prosumers are aggregated to form a smart grid based energy community managed by a central controller which could maximize their collective energy resource utilization. Using the central controller and distributed energy management systems, various mechanisms that harness the power profile of the energy community are developed for optimal, multi-objective energy management. The proposed mechanisms include resource-aware, multi-variable energy utility maximization objectives, namely: (1) maximizing the net green energy utilization, (2) maximizing the prosumers' level of comfortable, high quality power usage, and (3) maximizing the economic dispatch of energy storage units that minimize the net energy cost of the energy community. Moreover, an optimal energy management solution that combines the three objectives has been implemented by developing novel techniques of optimally flexible (un)certainty projection and appliance based pricing decomposition in an IBM ILOG CPLEX studio. A real-world, per-minute data from an energy community consisting of forty prosumers in Amsterdam, Netherlands is used. Results show that each of the proposed mechanisms yields significant increases in the aggregate energy resource utilization and welfare of prosumers as compared to traditional peak-power reduction methods. Furthermore, the multi-objective, resource-aware utility maximization approach leads to an optimal energy equilibrium and provides a sustainable energy management solution as verified by the Lagrangian method. The proposed resource-aware mechanisms could directly benefit emerging energy communities in the world to attain their energy resource utilization targets.

Bird community conservation and carbon offsets in western North America.

PubMed

Schuster, Richard; Martin, Tara G; Arcese, Peter

2014-01-01

Conservation initiatives to protect and restore valued species and communities in human-dominated landscapes face huge challenges linked to the cost of acquiring habitat. We ask how the sale of forest carbon offsets could reduce land acquisition costs, and how the alternate goals of maximizing α or β-diversity in focal communities could affect the prioritization land parcels over a range of conservation targets. Maximizing total carbon storage and carbon sequestration potential reduced land acquisition costs by up to 48%. Maximizing β rather than α-diversity within forest and savannah bird communities reduced acquisition costs by up to 15%, and when these solutions included potential carbon credit revenues, acquisition cost reductions up to 32% were achieved. However, the total cost of conservation networks increased exponentially as area targets increased in all scenarios. Our results indicate that carbon credit sales have the potential to enhance conservation outcomes in human-dominated landscapes by reducing the net acquisition costs of land conservation in old and maturing forests essential for the persistence of old forest plant and animal communities. Maximizing β versus α-diversity may further reduce costs by reducing the total area required to meet conservation targets and enhancing landscape heterogeneity. Although the potential value of carbon credit sales declined as a fraction of total acquisition costs, even conservative scenarios using a carbon credit value of $12.5/T suggest reductions in acquisition cost of up to $235 M, indicating that carbon credit sales could substantially reduce the costs of conservation.

Bird Community Conservation and Carbon Offsets in Western North America

PubMed Central

Schuster, Richard; Martin, Tara G.; Arcese, Peter

2014-01-01

Conservation initiatives to protect and restore valued species and communities in human-dominated landscapes face huge challenges linked to the cost of acquiring habitat. We ask how the sale of forest carbon offsets could reduce land acquisition costs, and how the alternate goals of maximizing α or β-diversity in focal communities could affect the prioritization land parcels over a range of conservation targets. Maximizing total carbon storage and carbon sequestration potential reduced land acquisition costs by up to 48%. Maximizing β rather than α-diversity within forest and savannah bird communities reduced acquisition costs by up to 15%, and when these solutions included potential carbon credit revenues, acquisition cost reductions up to 32% were achieved. However, the total cost of conservation networks increased exponentially as area targets increased in all scenarios. Our results indicate that carbon credit sales have the potential to enhance conservation outcomes in human-dominated landscapes by reducing the net acquisition costs of land conservation in old and maturing forests essential for the persistence of old forest plant and animal communities. Maximizing β versus α-diversity may further reduce costs by reducing the total area required to meet conservation targets and enhancing landscape heterogeneity. Although the potential value of carbon credit sales declined as a fraction of total acquisition costs, even conservative scenarios using a carbon credit value of $12.5/T suggest reductions in acquisition cost of up to $235 M, indicating that carbon credit sales could substantially reduce the costs of conservation. PMID:24918621

Model-based intensification of a fed-batch microbial process for the maximization of polyhydroxybutyrate (PHB) production rate.

PubMed

Penloglou, Giannis; Vasileiadou, Athina; Chatzidoukas, Christos; Kiparissides, Costas

2017-08-01

An integrated metabolic-polymerization-macroscopic model, describing the microbial production of polyhydroxybutyrate (PHB) in Azohydromonas lata bacteria, was developed and validated using a comprehensive series of experimental measurements. The model accounted for biomass growth, biopolymer accumulation, carbon and nitrogen sources utilization, oxygen mass transfer and uptake rates and average molecular weights of the accumulated PHB, produced under batch and fed-batch cultivation conditions. Model predictions were in excellent agreement with experimental measurements. The validated model was subsequently utilized to calculate optimal operating conditions and feeding policies for maximizing PHB productivity for desired PHB molecular properties. More specifically, two optimal fed-batch strategies were calculated and experimentally tested: (1) a nitrogen-limited fed-batch policy and (2) a nitrogen sufficient one. The calculated optimal operating policies resulted in a maximum PHB content (94% g/g) in the cultivated bacteria and a biopolymer productivity of 4.2 g/(l h), respectively. Moreover, it was demonstrated that different PHB grades with weight average molecular weights of up to 1513 kg/mol could be produced via the optimal selection of bioprocess operating conditions.

Evidence for surprise minimization over value maximization in choice behavior

PubMed Central

Schwartenbeck, Philipp; FitzGerald, Thomas H. B.; Mathys, Christoph; Dolan, Ray; Kronbichler, Martin; Friston, Karl

2015-01-01

Classical economic models are predicated on the idea that the ultimate aim of choice is to maximize utility or reward. In contrast, an alternative perspective highlights the fact that adaptive behavior requires agents’ to model their environment and minimize surprise about the states they frequent. We propose that choice behavior can be more accurately accounted for by surprise minimization compared to reward or utility maximization alone. Minimizing surprise makes a prediction at variance with expected utility models; namely, that in addition to attaining valuable states, agents attempt to maximize the entropy over outcomes and thus ‘keep their options open’. We tested this prediction using a simple binary choice paradigm and show that human decision-making is better explained by surprise minimization compared to utility maximization. Furthermore, we replicated this entropy-seeking behavior in a control task with no explicit utilities. These findings highlight a limitation of purely economic motivations in explaining choice behavior and instead emphasize the importance of belief-based motivations. PMID:26564686

Kinetics of CO2 diffusion in human carbonic anhydrase: a study using molecular dynamics simulations and the Markov-state model.

PubMed

Chen, Gong; Kong, Xian; Lu, Diannan; Wu, Jianzhong; Liu, Zheng

2017-05-10

Molecular dynamics (MD) simulations, in combination with the Markov-state model (MSM), were applied to probe CO 2 diffusion from an aqueous solution into the active site of human carbonic anhydrase II (hCA-II), an enzyme useful for enhanced CO 2 capture and utilization. The diffusion process in the hydrophobic pocket of hCA-II was illustrated in terms of a two-dimensional free-energy landscape. We found that CO 2 diffusion in hCA-II is a rate-limiting step in the CO 2 diffusion-binding-reaction process. The equilibrium distribution of CO 2 shows its preferential accumulation within a hydrophobic domain in the protein core region. An analysis of the committors and reactive fluxes indicates that the main pathway for CO 2 diffusion into the active site of hCA-II is through a binding pocket where residue Gln 136 contributes to the maximal flux. The simulation results offer a new perspective on the CO 2 hydration kinetics and useful insights toward the development of novel biochemical processes for more efficient CO 2 sequestration and utilization.

Utilization of acetone-butanol-ethanol-water mixture obtained from biomass fermentation as renewable feedstock for hydrogen production via steam reforming: Thermodynamic and energy analyses.

PubMed

Kumar, Brajesh; Kumar, Shashi; Sinha, Shishir; Kumar, Surendra

2018-08-01

A thermodynamic equilibrium analysis on steam reforming process to utilize acetone-butanol-ethanol-water mixture obtained from biomass fermentation as biorenewable fuel has been performed to produce clean energy carrier H 2 via non-stoichiometric approach namely Gibbs free energy minimization method. The effect of process variables such as temperature (573-1473 K), pressure (1-10 atm), and steam/fuel molar feed ratio (F ABE  = 5.5-12) have been investigated on equilibrium compositions of products, H 2 , CO, CO 2 , CH 4 and solid carbon. The best suitable conditions for maximization of desired product H 2 , suppression of CH 4 , and inhibition of solid carbon are 973 K, 1 atm, steam/fuel molar feed ratio = 12. Under these conditions, the maximum molar production of hydrogen is 8.35 with negligible formation of carbon and methane. Furthermore, the energy requirement per mol of H 2 (48.96 kJ), thermal efficiency (69.13%), exergy efficiency (55.09%), exergy destruction (85.36 kJ/mol), and generated entropy (0.29 kJ/mol.K) have been achieved at same operating conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Growth of the extremophilic Deinococcus geothermalis DSM 11302 using co-substrate fed-batch culture.

PubMed

Bornot, Julie; Molina-Jouve, Carole; Uribelarrea, Jean-Louis; Gorret, Nathalie

2014-02-01

Deinococcus geothermalis metabolism has been scarcely studied to date, although new developments on its utilization for bioremediation have been carried out. So, large-scale production of this strain and a better understanding of its physiology are required. A fed-batch experiment was conducted to achieve a high cell density non-limiting culture of D. geothermalis DSM 11302. A co-substrate nutritional strategy using glucose and yeast extract was carried out in a 20-L bioreactor in order to maintain a non-limited growth at a maximal growth rate of 1 h(-1) at 45 °C. Substrate supplies were adjusted by monitoring online culture parameters and physiological data (dissolved oxygen, gas analyses, respiratory quotient, biomass concentration). The results showed that yeast extract could serve as both carbon and nitrogen sources, although glucose and ammonia were consumed too. Yeast extract carbon-specific uptake rate reached a value 4.5 times higher than glucose carbon-specific uptake rate. Cell concentration of 9.6 g L(-1) dry cell weight corresponding to 99 g of biomass was obtained using glucose and yeast extract as carbon and nitrogen sources.

CO2 fixation by anaerobic non-photosynthetic mixotrophy for improved carbon conversion.

PubMed

Jones, Shawn W; Fast, Alan G; Carlson, Ellinor D; Wiedel, Carrissa A; Au, Jennifer; Antoniewicz, Maciek R; Papoutsakis, Eleftherios T; Tracy, Bryan P

2016-09-30

Maximizing the conversion of biogenic carbon feedstocks into chemicals and fuels is essential for fermentation processes as feedstock costs and processing is commonly the greatest operating expense. Unfortunately, for most fermentations, over one-third of sugar carbon is lost to CO 2 due to the decarboxylation of pyruvate to acetyl-CoA and limitations in the reducing power of the bio-feedstock. Here we show that anaerobic, non-photosynthetic mixotrophy, defined as the concurrent utilization of organic (for example, sugars) and inorganic (for example, CO 2 ) substrates in a single organism, can overcome these constraints to increase product yields and reduce overall CO 2 emissions. As a proof-of-concept, Clostridium ljungdahlii was engineered to produce acetone and achieved a mass yield 138% of the previous theoretical maximum using a high cell density continuous fermentation process. In addition, when enough reductant (that is, H 2 ) is provided, the fermentation emits no CO 2 . Finally, we show that mixotrophy is a general trait among acetogens.

Implementation of a Thick-Film Composite Li-Ion Microcathode Using Carbon Nanotubes as the Conductive Filler

NASA Technical Reports Server (NTRS)

Lin, Qian; Harb, John N.

2004-01-01

This paper describes the development of a thick-film microcathode for use in Li-ion microbatteries in order to provide increased power and energy per area. These cathodes take advantage of a composite porous electrode structure, utilizing carbon nanotubes (CNT) as the conductive filler. The use of carbon nanotubes was found to significantly reduce the measured resistance of the electrodes, increase active material accessibility, and improve electrode performance. In particular, the cycling and power performance of the thick-film cathodes was significantly improved, and the need for compression was eliminated. Cathode thickness and CNT content were optimized to maximize capacity and power performance. Power capability of >50 mW/sq cm (17 mA/sq cm) with discharge capacity of >0.17 mAh/sq cm was demonstrated. The feasibility of fabricating thick-film microcathodes capable of providing the power and capacity needed for use in autonomous microsensor systems was also demonstrated.

Coke formation and carbon atom economy of methanol-to-olefins reaction.

PubMed

Wei, Yingxu; Yuan, Cuiyu; Li, Jinzhe; Xu, Shutao; Zhou, You; Chen, Jingrun; Wang, Quanyi; Xu, Lei; Qi, Yue; Zhang, Qing; Liu, Zhongmin

2012-05-01

The methanol-to-olefins (MTO) process is becoming the most important non-petrochemical route for the production of light olefins from coal or natural gas. Maximizing the generation of the target products, ethene and propene, and minimizing the production of byproducts and coke, are major considerations in the efficient utilization of the carbon resource of methanol. In the present work, the heterogeneous catalytic conversion of methanol was evaluated by performing simultaneous measurements of the volatile products generated in the gas phase and the confined coke deposition in the catalyst phase. Real-time and complete reaction profiles were plotted to allow the comparison of carbon atom economy of methanol conversion over the catalyst SAPO-34 at varied reaction temperatures. The difference in carbon atom economy was closely related with the coke formation in the SAPO-34 catalyst. The confined coke compounds were determined. A new type of confined organics was found, and these accounted for the quick deactivation and low carbon atom economy under low-reaction-temperature conditions. Based on the carbon atom economy evaluation and coke species determination, optimized operating conditions for the MTO process are suggested; these conditions guarantee high conversion efficiency of methanol. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A steady-state stomatal model of balanced leaf gas exchange, hydraulics and maximal source-sink flux.

PubMed

Hölttä, Teemu; Lintunen, Anna; Chan, Tommy; Mäkelä, Annikki; Nikinmaa, Eero

2017-07-01

Trees must simultaneously balance their CO2 uptake rate via stomata, photosynthesis, the transport rate of sugars and rate of sugar utilization in sinks while maintaining a favourable water and carbon balance. We demonstrate using a numerical model that it is possible to understand stomatal functioning from the viewpoint of maximizing the simultaneous photosynthetic production, phloem transport and sink sugar utilization rate under the limitation that the transpiration-driven hydrostatic pressure gradient sets for those processes. A key feature in our model is that non-stomatal limitations to photosynthesis increase with decreasing leaf water potential and/or increasing leaf sugar concentration and are thus coupled to stomatal conductance. Maximizing the photosynthetic production rate using a numerical steady-state model leads to stomatal behaviour that is able to reproduce the well-known trends of stomatal behaviour in response to, e.g., light, vapour concentration difference, ambient CO2 concentration, soil water status, sink strength and xylem and phloem hydraulic conductance. We show that our results for stomatal behaviour are very similar to the solutions given by the earlier models of stomatal conductance derived solely from gas exchange considerations. Our modelling results also demonstrate how the 'marginal cost of water' in the unified stomatal conductance model and the optimal stomatal model could be related to plant structural and physiological traits, most importantly, the soil-to-leaf hydraulic conductance and soil moisture. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Cylindrical heat conduction and structural acoustic models for enclosed fiber array thermophones.

PubMed

Dzikowicz, Benjamin R; Tressler, James F; Baldwin, Jeffrey W

2017-11-01

Calculation of the heat loss for thermophone heating elements is a function of their geometry and the thermodynamics of their surroundings. Steady-state behavior is difficult to establish or evaluate as heat is only flowing in one direction in the device. However, for a heating element made from an array of carbon fibers in a planar enclosure, several assumptions can be made, leading to simple solutions of the heat equation. These solutions can be used to more carefully determine the efficiency of thermophones of this geometry. Acoustic response is predicted with the application of a Helmholtz resonator and thin plate structural acoustics models. A laboratory thermophone utilizing a sparse horizontal array of fine (6.7 μm diameter) carbon fibers is designed and tested. Experimental results are compared with the model. The model is also used to examine the optimal array density for maximal efficiency.

Biodegradation of polyethylene by the thermophilic bacterium Brevibacillus borstelensis.

PubMed

Hadad, D; Geresh, S; Sivan, A

2005-01-01

To select a polyethylene-degrading micro-organism and to study the factors affecting its biodegrading activity. A thermophilic bacterium Brevibaccillus borstelensis strain 707 (isolated from soil) utilized branched low-density polyethylene as the sole carbon source and degraded it. Incubation of polyethylene with B. borstelensis (30 days, 50 degrees C) reduced its gravimetric and molecular weights by 11 and 30% respectively. Brevibaccillus borstelensis also degraded polyethylene in the presence of mannitol. Biodegradation of u.v. photo-oxidized polyethylene increased with increasing irradiation time. Fourier Transform Infra-Red (FTIR) analysis of photo-oxidized polyethylene revealed a reduction in carbonyl groups after incubation with the bacteria. This study demonstrates that polyethylene--considered to be inert--can be biodegraded if the right microbial strain is isolated. Enrichment culture methods were effective for isolating a thermophilic bacterium capable of utilizing polyethylene as the sole carbon and energy source. Maximal biodegradation was obtained in combination with photo-oxidation, which showed that carbonyl residues formed by photo-oxidation play a role in biodegradation. Brevibaccillus borstelensis also degraded the CH2 backbone of nonirradiated polyethylene. Biodegradation of polyethylene by a single bacterial strain contributes to our understanding of the process and the factors affecting polyethylene biodegradation.

Method of inducing surface ensembles on a metal catalyst

DOEpatents

Miller, Steven S.

1989-01-01

A method of inducing surface ensembles on a transition metal catalyst used in the conversion of a reactant gas or gas mixture, such as carbon monoxide and hydrogen into hydrocarbons (the Fischer-Tropsch reaction) is disclosed which comprises adding a Lewis base to the syngas (CO+H.sub.2) mixture before reaction takes place. The formation of surface ensembles in this manner restricts the number and types of reaction pathways which will be utilized, thus greatly narrowing the product distribution and maximizing the efficiency of the Fischer-Tropsch reaction. Similarly, amines may also be produced by the conversion of reactant gas or gases, such as nitrogen, hydrogen, or hydrocarbon constituents.

Method of inducing surface ensembles on a metal catalyst

DOEpatents

Miller, S.S.

1987-10-02

A method of inducing surface ensembles on a transition metal catalyst used in the conversion of a reactant gas or gas mixture, such as carbon monoxide and hydrogen into hydrocarbons (the Fischer-Tropsch reaction) is disclosed which comprises adding a Lewis base to the syngas (CO + H/sub 2/) mixture before reaction takes place. The formation of surface ensembles in this manner restricts the number and types of reaction pathways which will be utilized, thus greatly narrowing the product distribution and maximizing the efficiency of the Fischer-Tropsch reaction. Similarly, amines may also be produced by the conversion of reactant gas or gases, such as nitrogen, hydrogen, or hydrocarbon constituents.

Automatic Control of Arc Process for Making Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Scott, Carl D.; Pulumbarit, Robert B.; Victor, Joe

2004-01-01

An automatic-control system has been devised for a process in which carbon nanotubes are produced in an arc between a catalyst-filled carbon anode and a graphite cathode. The control system includes a motor-driven screw that adjusts the distance between the electrodes. The system also includes a bridge circuit that puts out a voltage proportional to the difference between (1) the actual value of potential drop across the arc and (2) a reference value between 38 and 40 V (corresponding to a current of about 100 A) at which the yield of carbon nanotubes is maximized. Utilizing the fact that the potential drop across the arc increases with the interelectrode gap, the output of the bridge circuit is fed to a motor-control circuit that causes the motor to move the anode toward or away from the cathode if the actual potential drop is more or less, respectively, than the reference potential. Thus, the system regulates the interelectrode gap to maintain the optimum potential drop. The system also includes circuitry that records the potential drop across the arc and the relative position of the anode holder as function of time.

Health benefits, ecological threats of low-carbon electricity

NASA Astrophysics Data System (ADS)

Gibon, Thomas; Hertwich, Edgar G.; Arvesen, Anders; Singh, Bhawna; Verones, Francesca

2017-03-01

Stabilizing global temperature will require a shift to renewable or nuclear power from fossil power and the large-scale deployment of CO2 capture and storage (CCS) for remaining fossil fuel use. Non-climate co-benefits of low-carbon energy technologies, especially reduced mortalities from air pollution and decreased ecosystem damage, have been important arguments for policies to reduce CO2 emissions. Taking into account a wide range of environmental mechanisms and the complex interactions of the supply chains of different technologies, we conducted the first life cycle assessment of potential human health and ecological impacts of a global low-carbon electricity scenario. Our assessment indicates strong human health benefits of low-carbon electricity. For ecosystem quality, there is a significant trade-off between reduced pollution and climate impacts and potentially significant ecological impacts from land use associated with increased biopower utilization. Other renewables, nuclear power and CCS show clear ecological benefits, so that the climate mitigation scenario with a relatively low share of biopower has lower ecosystem impacts than the baseline scenario. Energy policy can maximize co-benefits by supporting other renewable and nuclear power and developing biomass supply from sources with low biodiversity impact.

Modeling forest stand dynamics from optimal balances of carbon and nitrogen

Treesearch

Harry T. Valentine; Annikki Makela

2012-01-01

We formulate a dynamic evolutionary optimization problem to predict the optimal pattern by which carbon (C) and nitrogen (N) are co-allocated to fine-root, leaf, and wood production, with the objective of maximizing height growth rate, year by year, in an even-aged stand. Height growth is maximized with respect to two adaptive traits, leaf N concentration and the ratio...

A comparative assessment of the financial costs and carbon benefits of REDD+ strategies in Southeast Asia

NASA Astrophysics Data System (ADS)

Graham, Victoria; Laurance, Susan G.; Grech, Alana; McGregor, Andrew; Venter, Oscar

2016-11-01

REDD+ holds potential for mitigating emissions from tropical forest loss by providing financial incentives for carbon stored in forests, but its economic viability is under scrutiny. The primary narrative raised in the literature is that REDD+ will be of limited utility for reducing forest carbon loss in Southeast Asia, while the level of finance committed falls short of profits from alternative land-use activities in the region, including large-scale timber and oil palm operations. Here we assess the financial costs and carbon benefits of various REDD+ strategies deployed in the region. We find the cost of reducing emissions ranges from 9 to 75 per tonne of avoided carbon emissions. The strategies focused on reducing forest degradation and promoting forest regrowth are the most cost-effective ways of reducing emissions and used in over 60% of REDD+ projects. By comparing the financial costs and carbon benefits of a broader range of strategies than previously assessed, we highlight the variation between different strategies and draw attention to opportunities where REDD+ can achieve maximum carbon benefits cost-effectively. These findings have broad policy implications for Southeast Asia. Until carbon finance escalates, emissions reductions can be maximized from reforestation, reduced-impact logging and investing in improved management of protected areas. Targeting cost-efficient opportunities for REDD+ is important to improve the efficiency of national REDD+ policy, which in-turn fosters greater financial and political support for the scheme.

Optimization in the utility maximization framework for conservation planning: a comparison of solution procedures in a study of multifunctional agriculture

PubMed Central

Stoms, David M.; Davis, Frank W.

2014-01-01

Quantitative methods of spatial conservation prioritization have traditionally been applied to issues in conservation biology and reserve design, though their use in other types of natural resource management is growing. The utility maximization problem is one form of a covering problem where multiple criteria can represent the expected social benefits of conservation action. This approach allows flexibility with a problem formulation that is more general than typical reserve design problems, though the solution methods are very similar. However, few studies have addressed optimization in utility maximization problems for conservation planning, and the effect of solution procedure is largely unquantified. Therefore, this study mapped five criteria describing elements of multifunctional agriculture to determine a hypothetical conservation resource allocation plan for agricultural land conservation in the Central Valley of CA, USA. We compared solution procedures within the utility maximization framework to determine the difference between an open source integer programming approach and a greedy heuristic, and find gains from optimization of up to 12%. We also model land availability for conservation action as a stochastic process and determine the decline in total utility compared to the globally optimal set using both solution algorithms. Our results are comparable to other studies illustrating the benefits of optimization for different conservation planning problems, and highlight the importance of maximizing the effectiveness of limited funding for conservation and natural resource management. PMID:25538868

Optimization in the utility maximization framework for conservation planning: a comparison of solution procedures in a study of multifunctional agriculture

USGS Publications Warehouse

Kreitler, Jason R.; Stoms, David M.; Davis, Frank W.

2014-01-01

Quantitative methods of spatial conservation prioritization have traditionally been applied to issues in conservation biology and reserve design, though their use in other types of natural resource management is growing. The utility maximization problem is one form of a covering problem where multiple criteria can represent the expected social benefits of conservation action. This approach allows flexibility with a problem formulation that is more general than typical reserve design problems, though the solution methods are very similar. However, few studies have addressed optimization in utility maximization problems for conservation planning, and the effect of solution procedure is largely unquantified. Therefore, this study mapped five criteria describing elements of multifunctional agriculture to determine a hypothetical conservation resource allocation plan for agricultural land conservation in the Central Valley of CA, USA. We compared solution procedures within the utility maximization framework to determine the difference between an open source integer programming approach and a greedy heuristic, and find gains from optimization of up to 12%. We also model land availability for conservation action as a stochastic process and determine the decline in total utility compared to the globally optimal set using both solution algorithms. Our results are comparable to other studies illustrating the benefits of optimization for different conservation planning problems, and highlight the importance of maximizing the effectiveness of limited funding for conservation and natural resource management.

Optimal nanomaterial concentration: harnessing percolation theory to enhance polymer nanocomposite performance

NASA Astrophysics Data System (ADS)

Nadiv, Roey; Shtein, Michael; Shachar, Gal; Varenik, Maxim; Regev, Oren

2017-07-01

A major challenge in nanocomposite research is to predict the optimal nanomaterial concentration (ONC) yielding a maximal reinforcement in a given property. We present a simple approach to identify the ONC based on our finding that it is typically located in close proximity to an abrupt increase in polymer matrix viscosity, termed the rheological percolation threshold, and thus may be used as an indicator of the ONC. This premise was validated by rheological and fractography studies of composites loaded by nanomaterials including graphene nanoribbons or carbon or tungsten disulfide nanotubes. The correlation between in situ viscosity, the rheological percolation threshold concentration and the nanocomposite fractography demonstrates the utility of the method.

Optimal nanomaterial concentration: harnessing percolation theory to enhance polymer nanocomposite performance.

PubMed

Nadiv, Roey; Shtein, Michael; Shachar, Gal; Varenik, Maxim; Regev, Oren

2017-07-28

A major challenge in nanocomposite research is to predict the optimal nanomaterial concentration (ONC) yielding a maximal reinforcement in a given property. We present a simple approach to identify the ONC based on our finding that it is typically located in close proximity to an abrupt increase in polymer matrix viscosity, termed the rheological percolation threshold, and thus may be used as an indicator of the ONC. This premise was validated by rheological and fractography studies of composites loaded by nanomaterials including graphene nanoribbons or carbon or tungsten disulfide nanotubes. The correlation between in situ viscosity, the rheological percolation threshold concentration and the nanocomposite fractography demonstrates the utility of the method.

Soil Carbon Storage in Christmas Tree Farms: Maximizing Ecosystem Management and Sustainability for Carbon Sequestration

NASA Astrophysics Data System (ADS)

Chapman, S. K.; Shaw, R.; Langley, A.

2008-12-01

Management of agroecosystems for the purpose of manipulating soil carbon stocks could be a viable approach for countering rising atmospheric carbon dioxide concentrations, while maximizing sustainability of the agroforestry industry. We investigated the carbon storage potential of Christmas tree farms in the southern Appalachian mountains as a potential model for the impacts of land management on soil carbon. We quantified soil carbon stocks across a gradient of cultivation duration and herbicide management. We compared soil carbon in farms to that in adjacent pastures and native forests that represent a control group to account for variability in other soil-forming factors. We partitioned tree farm soil carbon into fractions delineated by stability, an important determinant of long-term sequestration potential. Soil carbon stocks in the intermediate pool are significantly greater in the tree farms under cultivation for longer periods of time than in the younger tree farms. This pool can be quite large, yet has the ability to repond to biological environmental changes on the centennial time scale. Pasture soil carbon was significantly greater than both forest and tree farm soil carbon, which were not different from each other. These data can help inform land management and soil carbon sequestration strategies.

Maximizing Resource Utilization in Video Streaming Systems

ERIC Educational Resources Information Center

Alsmirat, Mohammad Abdullah

2013-01-01

Video streaming has recently grown dramatically in popularity over the Internet, Cable TV, and wire-less networks. Because of the resource demanding nature of video streaming applications, maximizing resource utilization in any video streaming system is a key factor to increase the scalability and decrease the cost of the system. Resources to…

Trash to Gas: Converting Space Waste into Useful Supply Products

NASA Technical Reports Server (NTRS)

Tsoras, Alexandra

2013-01-01

The cost of sending mass into space with current propulsion technology is very expensive, making every item a crucial element of the space mission. It is essential that all materials be used to their fullest potential. Items like food, packaging, clothing, paper towels, gloves, etc., normally become trash and take up space after use. These waste materials are currently either burned up upon reentry in earth's atmosphere or sent on cargo return vehicles back to earth: a very wasteful method. The purpose of this project was to utilize these materials and create useful products like water and methane gas, which is used for rocket fuel, to further supply a deep space mission. The system used was a thermal degradation reactor with the configuration of a down-draft gasifier. The reactor was loaded with approximately 100g of trash simulant and heated with two external ceramic heaters with separate temperature control in order to create pyrolysis and gasification in one zone and incineration iri a second zone simultaneously. Trash was loaded into the top half of the reactor to undergo pyrolysis while the downdraft gas experienced gasification or incineration to treat tars and maximize the production of carbon dioxide. Minor products included carbon monoxide, methane, and other hydrocarbons. The carbon dioxide produced can be sent to a Sabatier reactor to convert the gas into methane, which can be used as rocket propellant. In order to maximize the carbon dioxide and useful gases produced, and minimize the unwanted tars and leftover ashen material, multiple experiments were performed with altered parameters such as differing temperatures, flow rates, and location of inlet air flow. According to the data received from these experiments, the process will be further scaled up and optimized to ultimately create a system that reduces trash buildup while at the same time providing enough useful gases to potentially fill a methane tank that could fuel a lunar ascent vehicle or other deep space mission.

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

Tucker, Michael C.; Phillips, Adam; Weber, Adam Z.

We proposed and developed an all-iron redox flow battery for end users without access to an electricity grid. The concept is a low-cost battery which the user assembles, discharges, and then disposes of the active materials. Our design goals are: (1) minimize upfront cost, (2) maximize discharge energy, and (3) utilize non-toxic and environmentally benign materials. These are different goals than typically considered for electrochemical battery technology, which provides the opportunity for a novel solution. The selected materials are: low-carbon-steel negative electrode, paper separator, porous-carbon-paper positive electrode, and electrolyte solution containing 0.5 m Fe 2 (SO 4 ) 3 activemore » material and 1.2 m NaCl supporting electrolyte. Furthermore, with these materials, an average power density around 20 mW cm -2 and a maximum energy density of 11.5 Wh L -1 are achieved. A simple cost model indicates the consumable materials cost US$6.45 per kWh -1 , or only US$0.034 per mobile phone charge.« less

Carbon Dioxide Reduction Post-Processing Sub-System Development

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Miller, Lee A.; Greenwood, Zachary; Barton, Katherine

2012-01-01

The state-of-the-art Carbon Dioxide (CO2) Reduction Assembly (CRA) on the International Space Station (ISS) facilitates the recovery of oxygen from metabolic CO2. The CRA utilizes the Sabatier process to produce water with methane as a byproduct. The methane is currently vented overboard as a waste product. Because the CRA relies on hydrogen for oxygen recovery, the loss of methane ultimately results in a loss of oxygen. For missions beyond low earth orbit, it will prove essential to maximize oxygen recovery. For this purpose, NASA is exploring an integrated post-processor system to recover hydrogen from CRA methane. The post-processor, called a Plasma Pyrolysis Assembly (PPA) partially pyrolyzes methane to recover hydrogen with acetylene as a byproduct. In-flight operation of post-processor will require a Methane Purification Assembly (MePA) and an Acetylene Separation Assembly (ASepA). Recent efforts have focused on the design, fabrication, and testing of these components. The results and conclusions of these efforts will be discussed as well as future plans.

Flexible power fabrics made of carbon nanotubes for harvesting thermoelectricity.

PubMed

Kim, Suk Lae; Choi, Kyungwho; Tazebay, Abdullah; Yu, Choongho

2014-03-25

Thermoelectric energy conversion is very effective in capturing low-grade waste heat to supply electricity particularly to small devices such as sensors, wireless communication units, and wearable electronics. Conventional thermoelectric materials, however, are often inadequately brittle, expensive, toxic, and heavy. We developed both p- and n-type fabric-like flexible lightweight materials by functionalizing the large surfaces and junctions in carbon nanotube (CNT) mats. The poor thermopower and only p-type characteristics of typical CNTs have been converted into both p- and n-type with high thermopower. The changes in the electronic band diagrams of the CNTs were experimentally investigated, elucidating the carrier type and relatively large thermopower values. With our optimized device design to maximally utilize temperature gradients, an electrochromic glucose sensor was successfully operated without batteries or external power supplies, demonstrating self-powering capability. While our fundamental study provides a method of tailoring electronic transport properties, our device-level integration shows the feasibility of harvesting electrical energy by attaching the device to even curved surfaces like human bodies.

Production of 1,2-propanediol in photoautotrophic Synechocystis is linked to glycogen turn-over.

PubMed

David, Christian; Schmid, Andreas; Adrian, Lorenz; Wilde, Annegret; Bühler, Katja

2018-02-01

We utilized a photoautotrophic organism to synthesize 1,2-propanediol from carbon dioxide and water fueled by light. A synthetic pathway comprising mgsA (methylglyoxal synthase), yqhD (aldehyde reductase), and adh (alcohol dehydrogenase) was inserted into Synechocystis sp. PCC6803 to convert dihydroxyacetone phosphate to methylglyoxal, which is subsequently reduced to acetol and then to 1,2-propanediol. 1,2-propanediol could be successfully produced by Synechocystis, at an approximate rate of 55 μmol h -1  g CDW -1 . Surprisingly, maximal productivity was observed in the stationary phase. The production of 1,2-propanediol was clearly coupled to the turn-over of intracellular glycogen. Upon depletion of the glycogen pool, product formation stopped. Reducing the carbon flux to glycogen significantly decreased final product titers. Optimization of cultivation conditions allowed final product titers of almost 1 g L -1 (12 mM), which belongs to the highest values published so far for photoautotrophic production of this compound. © 2017 Wiley Periodicals, Inc.

Ultrathin Coating of Confined Pt Nanocatalysts by Atomic Layer Deposition for Enhanced Catalytic Performance in Hydrogenation Reactions.

PubMed

Wang, Meihua; Gao, Zhe; Zhang, Bin; Yang, Huimin; Qiao, Yan; Chen, Shuai; Ge, Huibin; Zhang, Jiankang; Qin, Yong

2016-06-13

Metal-support interfaces play a prominent role in heterogeneous catalysis. However, tailoring the metal-support interfaces to realize full utilization remains a major challenge. In this work, we propose a graceful strategy to maximize the metal-oxide interfaces by coating confined nanoparticles with an ultrathin oxide layer. This is achieved by sequential deposition of ultrathin Al2 O3 coats, Pt, and a thick Al2 O3 layer on carbon nanocoils templates by atomic layer deposition (ALD), followed by removal of the templates. Compared with the Pt catalysts confined in Al2 O3 nanotubes without the ultrathin coats, the ultrathin coated samples have larger Pt-Al2 O3 interfaces. The maximized interfaces significantly improve the activity and the protecting Al2 O3 nanotubes retain the stability for hydrogenation reactions of 4-nitrophenol. We believe that applying ALD ultrathin coats on confined catalysts is a promising way to achieve enhanced performance for other catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Estimating the carbon budget and maximizing future carbon uptake for a temperate forest region in the U.S.

Treesearch

Scott D. Peckham; Stith T. Gower; Joseph Buongiorno

2012-01-01

Forests of the Midwest U.S. provide numerous ecosystem services. Two of these, carbon sequestration and wood production, are often portrayed as conflicting. Currently, carbon management and biofuel policies are being developed to reduce atmospheric CO2 and national dependence on foreign oil, and increase carbon storage in ecosystems. However, the biological and...

Team Formation in Partially Observable Multi-Agent Systems

NASA Technical Reports Server (NTRS)

Agogino, Adrian K.; Tumer, Kagan

2004-01-01

Sets of multi-agent teams often need to maximize a global utility rating the performance of the entire system where a team cannot fully observe other teams agents. Such limited observability hinders team-members trying to pursue their team utilities to take actions that also help maximize the global utility. In this article, we show how team utilities can be used in partially observable systems. Furthermore, we show how team sizes can be manipulated to provide the best compromise between having easy to learn team utilities and having them aligned with the global utility, The results show that optimally sized teams in a partially observable environments outperform one team in a fully observable environment, by up to 30%.

Maximizing the use of local materials in HMA surfaces.

DOT National Transportation Integrated Search

2012-04-01

One approach to reducing initial construction costs is to maximize the use of locally available aggregates. The main concern with using : locally available carbonate aggregates, however, is that they tend to polish under traffic and provide inadequat...

Air quality and climate benefits of long-distance electricity transmission in China

NASA Astrophysics Data System (ADS)

Peng, Wei; Yuan, Jiahai; Zhao, Yu; Lin, Meiyun; Zhang, Qiang; Victor, David G.; Mauzerall, Denise L.

2017-06-01

China is the world’s top carbon emitter and suffers from severe air pollution. It has recently made commitments to improve air quality and to peak its CO2 emissions by 2030. We examine one strategy that can potentially address both issues—utilizing long-distance electricity transmission to bring renewable power to the polluted eastern provinces. Based on an integrated assessment using state-of-the-science atmospheric modeling and recent epidemiological evidence, we find that transmitting a hybrid of renewable (60%) and coal power (40%) (Hybrid-by-wire) reduces 16% more national air-pollution-associated deaths and decreases three times more carbon emissions than transmitting only coal-based electricity. Moreover, although we find that transmitting coal power (Coal-by-Wire, CbW) is slightly more effective at reducing air pollution impacts than replacing old coal power plants with newer cleaner ones in the east (Coal-by-Rail, CbR) (CbW achieves a 6% greater reduction in national total air-pollution-related mortalities than CbR), both coal scenarios have approximately the same carbon emissions. We thus demonstrate that coordinating transmission planning with renewable energy deployment is critical to maximize both local air quality benefits and global climate benefits.

Monitoring and Predicting the Export and Fate of Global Ocean Net Primary Production: The EXPORTS Field Program

NASA Astrophysics Data System (ADS)

Exports Science Definition Team

2016-04-01

Ocean ecosystems play a critical role in the Earth's carbon cycle and its quantification on global scales remains one of the greatest challenges in global ocean biogeochemistry. The goal of the EXport Processes in the Ocean from Remote Sensing (EXPORTS) science plan is to develop a predictive understanding of the export and fate of global ocean primary production and its implications for the Earth's carbon cycle in present and future climates. NASA's satellite ocean-color data record has revolutionized our understanding of global marine systems. EXPORTS is designed to advance the utility of NASA ocean color assets to predict how changes in ocean primary production will impact the global carbon cycle. EXPORTS will create a predictive understanding of both the export of organic carbon from the euphotic zone and its fate in the underlying "twilight zone" (depths of 500 m or more) where variable fractions of exported organic carbon are respired back to CO2. Ultimately, it is the sequestration of deep organic carbon transport that defines the impact of ocean biota on atmospheric CO2 levels and hence climate. EXPORTS will generate a new, detailed understanding of ocean carbon transport processes and pathways linking upper ocean phytoplankton processes to the export and fate of organic matter in the underlying twilight zone using a combination of field campaigns, remote sensing and numerical modeling. The overarching objective for EXPORTS is to ensure the success of future satellite missions by establishing mechanistic relationships between remotely sensed signals and carbon cycle processes. Through a process-oriented approach, EXPORTS will foster new insights on ocean carbon cycling that will maximize its societal relevance and be a key component in the U.S. investment to understand Earth as an integrated system.

Three-class ROC analysis--the equal error utility assumption and the optimality of three-class ROC surface using the ideal observer.

PubMed

He, Xin; Frey, Eric C

2006-08-01

Previously, we have developed a decision model for three-class receiver operating characteristic (ROC) analysis based on decision theory. The proposed decision model maximizes the expected decision utility under the assumption that incorrect decisions have equal utilities under the same hypothesis (equal error utility assumption). This assumption reduced the dimensionality of the "general" three-class ROC analysis and provided a practical figure-of-merit to evaluate the three-class task performance. However, it also limits the generality of the resulting model because the equal error utility assumption will not apply for all clinical three-class decision tasks. The goal of this study was to investigate the optimality of the proposed three-class decision model with respect to several other decision criteria. In particular, besides the maximum expected utility (MEU) criterion used in the previous study, we investigated the maximum-correctness (MC) (or minimum-error), maximum likelihood (ML), and Nyman-Pearson (N-P) criteria. We found that by making assumptions for both MEU and N-P criteria, all decision criteria lead to the previously-proposed three-class decision model. As a result, this model maximizes the expected utility under the equal error utility assumption, maximizes the probability of making correct decisions, satisfies the N-P criterion in the sense that it maximizes the sensitivity of one class given the sensitivities of the other two classes, and the resulting ROC surface contains the maximum likelihood decision operating point. While the proposed three-class ROC analysis model is not optimal in the general sense due to the use of the equal error utility assumption, the range of criteria for which it is optimal increases its applicability for evaluating and comparing a range of diagnostic systems.

Aging and loss decision making: increased risk aversion and decreased use of maximizing information, with correlated rationality and value maximization.

PubMed

Kurnianingsih, Yoanna A; Sim, Sam K Y; Chee, Michael W L; Mullette-Gillman, O'Dhaniel A

2015-01-01

We investigated how adult aging specifically alters economic decision-making, focusing on examining alterations in uncertainty preferences (willingness to gamble) and choice strategies (what gamble information influences choices) within both the gains and losses domains. Within each domain, participants chose between certain monetary outcomes and gambles with uncertain outcomes. We examined preferences by quantifying how uncertainty modulates choice behavior as if altering the subjective valuation of gambles. We explored age-related preferences for two types of uncertainty, risk, and ambiguity. Additionally, we explored how aging may alter what information participants utilize to make their choices by comparing the relative utilization of maximizing and satisficing information types through a choice strategy metric. Maximizing information was the ratio of the expected value of the two options, while satisficing information was the probability of winning. We found age-related alterations of economic preferences within the losses domain, but no alterations within the gains domain. Older adults (OA; 61-80 years old) were significantly more uncertainty averse for both risky and ambiguous choices. OA also exhibited choice strategies with decreased use of maximizing information. Within OA, we found a significant correlation between risk preferences and choice strategy. This linkage between preferences and strategy appears to derive from a convergence to risk neutrality driven by greater use of the effortful maximizing strategy. As utility maximization and value maximization intersect at risk neutrality, this result suggests that OA are exhibiting a relationship between enhanced rationality and enhanced value maximization. While there was variability in economic decision-making measures within OA, these individual differences were unrelated to variability within examined measures of cognitive ability. Our results demonstrate that aging alters economic decision-making for losses through changes in both individual preferences and the strategies individuals employ.

Platinum single-atom and cluster catalysis of the hydrogen evolution reaction

NASA Astrophysics Data System (ADS)

Cheng, Niancai; Stambula, Samantha; Wang, Da; Banis, Mohammad Norouzi; Liu, Jian; Riese, Adam; Xiao, Biwei; Li, Ruying; Sham, Tsun-Kong; Liu, Li-Min; Botton, Gianluigi A.; Sun, Xueliang

2016-11-01

Platinum-based catalysts have been considered the most effective electrocatalysts for the hydrogen evolution reaction in water splitting. However, platinum utilization in these electrocatalysts is extremely low, as the active sites are only located on the surface of the catalyst particles. Downsizing catalyst nanoparticles to single atoms is highly desirable to maximize their efficiency by utilizing nearly all platinum atoms. Here we report on a practical synthesis method to produce isolated single platinum atoms and clusters using the atomic layer deposition technique. The single platinum atom catalysts are investigated for the hydrogen evolution reaction, where they exhibit significantly enhanced catalytic activity (up to 37 times) and high stability in comparison with the state-of-the-art commercial platinum/carbon catalysts. The X-ray absorption fine structure and density functional theory analyses indicate that the partially unoccupied density of states of the platinum atoms' 5d orbitals on the nitrogen-doped graphene are responsible for the excellent performance.

Platinum single-atom and cluster catalysis of the hydrogen evolution reaction

PubMed Central

Cheng, Niancai; Stambula, Samantha; Wang, Da; Banis, Mohammad Norouzi; Liu, Jian; Riese, Adam; Xiao, Biwei; Li, Ruying; Sham, Tsun-Kong; Liu, Li-Min; Botton, Gianluigi A.; Sun, Xueliang

2016-01-01

Platinum-based catalysts have been considered the most effective electrocatalysts for the hydrogen evolution reaction in water splitting. However, platinum utilization in these electrocatalysts is extremely low, as the active sites are only located on the surface of the catalyst particles. Downsizing catalyst nanoparticles to single atoms is highly desirable to maximize their efficiency by utilizing nearly all platinum atoms. Here we report on a practical synthesis method to produce isolated single platinum atoms and clusters using the atomic layer deposition technique. The single platinum atom catalysts are investigated for the hydrogen evolution reaction, where they exhibit significantly enhanced catalytic activity (up to 37 times) and high stability in comparison with the state-of-the-art commercial platinum/carbon catalysts. The X-ray absorption fine structure and density functional theory analyses indicate that the partially unoccupied density of states of the platinum atoms' 5d orbitals on the nitrogen-doped graphene are responsible for the excellent performance. PMID:27901129

The general utilization of scrapped PC board.

PubMed

Liu, Robert; Shieh, R S; Yeh, Ruth Y L; Lin, C H

2009-11-01

The traditional burning process is used to recover copper from scrapped PC board (printed circuit board) but it causes serious environmental problems. In this research a new process was developed which not only prevents pollution problems, but also maximizes the utility of all the materials on the waste board. First, the scrapped PC board was crushed and grounded, then placed in the NH3/NH5CO3 solution with aeration in order to dissolve copper. After distilling the copper NH3/NH5CO3 solution and then heating the distilled residue of copper carbonate, pure copper oxide was obtained with particle size of about 0.2 microm and the shape elliptical. The remaining solid residue after copper removal was then leached with 6N hydrochloric acid to remove tin and lead. The last residue was used as a filler in PVC plastics. The PVC plastics with PC board powder as filling material was found to have the same tensile strength as unfilled plastics, but had higher elastic modulus, higher abrasion resistance, and was cheaper.

Adoption of Emissions Abating Technologies by U.S. Electricity Producing Firms Under the SO2 Emission Allowance Market

NASA Astrophysics Data System (ADS)

Creamer, Gregorio Bernardo

The objective of this research is to determine the adaptation strategies that coal-based, electricity producing firms in the United States utilize to comply with the emission control regulations imposed by the SO2 Emissions Allowance Market created by the Clean Air Act Amendment of 1990, and the effect of market conditions on the decision making process. In particular, I take into consideration (1) the existence of carbon contracts for the provision of coal that may a affect coal prices at the plant level, and (2) local and geographical conditions, as well as political arrangements that may encourage firms to adopt strategies that appear socially less efficient. As the electricity producing sector is a regulated sector, firms do not necessarily behave in a way that maximizes the welfare of society when reacting to environmental regulations. In other words, profit maximization actions taken by the firm do not necessarily translate into utility maximization for society. Therefore, the environmental regulator has to direct firms into adopting strategies that are socially efficient, i.e., that maximize utility. The SO 2 permit market is an instrument that allows each firm to reduce marginal emissions abatement costs according to their own production conditions and abatement costs. Companies will be driven to opt for a cost-minimizing emissions abatement strategy or a combination of abatement strategies when adapting to new environmental regulations or markets. Firms may adopt one or more of the following strategies to reduce abatement costs while meeting the emission constraints imposed by the SO2 Emissions Allowance Market: (1) continue with business as usual on the production site while buying SO2 permits to comply with environmental regulations, (2) switch to higher quality, lower sulfur coal inputs that will generate less SO2 emissions, or (3) adopting new emissions abating technologies. A utility optimization condition is that the marginal value of each input should be equal to the product generated by using it and to the activities that are required by new regulations. The comparative technological and scale efficiency factors of coal-based electricity producing plants are calculated using the Data Envelopment Analysis (DEA) framework, and used as proxies to test this condition. In the empirical analysis, econometric models of the response of firms to emissions control are analyzed around the following aspects: (1) characterization of the behavior of firms and their efficiency, (2) relevant variables that trigger the adoption of technology, that is, the acquisition of scrubbers , and (3) the influence of exogenous variables, such as the existence of contracts, distance from mine to plant, and local conditions of the region where plants are located.

Assessing the potential to sequester carbon within state highway rights-of-way in New Mexico phase 2: development of a right-of-way carbon sequestration program.

DOT National Transportation Integrated Search

2016-06-13

The New Mexico Department of Transportation (NMDOT) was selected by the Federal Highway : Administration (FHWA) to determine the feasibility of maximizing carbon sequestration within state : highway rightsofway (ROW). Golder Associates Inc. was...

Weak overturning circulation and increased iron fertilization maximized carbon storage in the glacial ocean

NASA Astrophysics Data System (ADS)

Muglia, J.; Skinner, L.; Schmittner, A.

2017-12-01

Circulation changes have been suggested to play an important role in the sequestration of atmospheric CO2 in the glacial ocean. However, previous studies have resulted in contradictory results regarding the strength of the Atlantic Meridional Overturning Circulation (AMOC) and three-dimensional, quantitative reconstructions of the glacial ocean constrained by multiple proxies remain lacking. Here we simulate the modern and glacial ocean using a coupled, global, three-dimensional, physical-biogeochemical model constrained simultaneously by d13C, radiocarbon, and d15N to explore the effects of AMOC differences and Southern Ocean iron fertilization on the distributions of these isotopes and ocean carbon storage. We show that d13C and radiocarbon data sparsely sampled at the locations of existing glacial sediment cores can be used to reconstruct the modern AMOC accurately. Applying this method to the glacial ocean we find that a surprisingly weak (6-9 Sv or about half of today's) and shallow AMOC maximizes carbon storage and best reproduces the sediment data. Increasing the atmospheric soluble iron flux in the model's Southern Ocean intensifies export production, carbon storage, and improves agreement with d13C and d15N reconstructions. Our best fitting model is a significant improvement compared with previous studies. It suggests that a weak and shallow AMOC and enhanced iron fertilization conspired to maximize carbon storage in the glacial ocean.

Statistical optimization of growth medium for the production of the entomopathogenic and phytotoxic cyclic depsipeptide beauvericin from Fusarium oxysporum KFCC 11363P.

PubMed

Lee, Hee-Seok; Song, Hyuk-Hwan; An, Joong-Hoon; Shin, Cha-Gyun; Lee, Gung Pyo; Lee, Chan

2008-01-01

The production of the entomopathogenic and phytotoxic cyclic depsipeptide beauvericin (BEA) was studied in submerged cultures of Fusarium oxysporum KFCC 11363P isolated in Korea. The influences of various factors on mycelia growth and BEA production were examined in both complete and chemically defined culture media. The mycelia growth and BEA production were highest in Fusarium defined medium. The optimal carbon and nitrogen sources for maximizing BEA production were glucose and NaNO3, respectively. The carbon/ nitrogen ratio for maximal production of BEA was investigated using response surface methodology (RSM). Equations derived by differentiation of the RSM model revealed that the production of BEA was maximal when using 108 mM glucose and 25 mM NaNO3.

Planning Routes Across Economic Terrains: Maximizing Utility, Following Heuristics

PubMed Central

Zhang, Hang; Maddula, Soumya V.; Maloney, Laurence T.

2010-01-01

We designed an economic task to investigate human planning of routes in landscapes where travel in different kinds of terrain incurs different costs. Participants moved their finger across a touch screen from a starting point to a destination. The screen was divided into distinct kinds of terrain and travel within each kind of terrain imposed a cost proportional to distance traveled. We varied costs and spatial configurations of terrains and participants received fixed bonuses minus the total cost of the routes they chose. We first compared performance to a model maximizing gain. All but one of 12 participants failed to adopt least-cost routes and their failure to do so reduced their winnings by about 30% (median value). We tested in detail whether participants’ choices of routes satisfied three necessary conditions (heuristics) for a route to maximize gain. We report failures of one heuristic for 7 out of 12 participants. Last of all, we modeled human performance with the assumption that participants assign subjective utilities to costs and maximize utility. For 7 out 12 participants, the fitted utility function was an accelerating power function of actual cost and for the remaining 5, a decelerating power function. We discuss connections between utility aggregation in route planning and decision under risk. Our task could be adapted to investigate human strategy and optimality of route planning in full-scale landscapes. PMID:21833269

Facilitating CCS Business Planning by Extending the Functionality of the SimCCS Integrated System Model

DOE PAGES

Ellett, Kevin M.; Middleton, Richard S.; Stauffer, Philip H.; ...

2017-08-18

The application of integrated system models for evaluating carbon capture and storage technology has expanded steadily over the past few years. To date, such models have focused largely on hypothetical scenarios of complex source-sink matching involving numerous large-scale CO 2 emitters, and high-volume, continuous reservoirs such as deep saline formations to function as geologic sinks for carbon storage. Though these models have provided unique insight on the potential costs and feasibility of deploying complex networks of integrated infrastructure, there remains a pressing need to translate such insight to the business community if this technology is to ever achieve a trulymore » meaningful impact in greenhouse gas mitigation. Here, we present a new integrated system modelling tool termed SimCCUS aimed at providing crucial decision support for businesses by extending the functionality of a previously developed model called SimCCS. The primary innovation of the SimCCUS tool development is the incorporation of stacked geological reservoir systems with explicit consideration of processes and costs associated with the operation of multiple CO 2 utilization and storage targets from a single geographic location. In such locations provide significant efficiencies through economies of scale, effectively minimizing CO 2 storage costs while simultaneously maximizing revenue streams via the utilization of CO 2 as a commodity for enhanced hydrocarbon recovery.« less

Facilitating CCS Business Planning by Extending the Functionality of the SimCCS Integrated System Model

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

Ellett, Kevin M.; Middleton, Richard S.; Stauffer, Philip H.

The application of integrated system models for evaluating carbon capture and storage technology has expanded steadily over the past few years. To date, such models have focused largely on hypothetical scenarios of complex source-sink matching involving numerous large-scale CO 2 emitters, and high-volume, continuous reservoirs such as deep saline formations to function as geologic sinks for carbon storage. Though these models have provided unique insight on the potential costs and feasibility of deploying complex networks of integrated infrastructure, there remains a pressing need to translate such insight to the business community if this technology is to ever achieve a trulymore » meaningful impact in greenhouse gas mitigation. Here, we present a new integrated system modelling tool termed SimCCUS aimed at providing crucial decision support for businesses by extending the functionality of a previously developed model called SimCCS. The primary innovation of the SimCCUS tool development is the incorporation of stacked geological reservoir systems with explicit consideration of processes and costs associated with the operation of multiple CO 2 utilization and storage targets from a single geographic location. In such locations provide significant efficiencies through economies of scale, effectively minimizing CO 2 storage costs while simultaneously maximizing revenue streams via the utilization of CO 2 as a commodity for enhanced hydrocarbon recovery.« less

Calibration of remotely sensed, coarse resolution NDVI to CO2 fluxes in a sagebrush–steppe ecosystem

USGS Publications Warehouse

Wylie, Bruce K.; Johnson, Douglas A.; Laca, Emilio; Saliendra, Nicanor Z.; Gilmanov, Tagir G.; Reed, Bradley C.; Tieszen, Larry L.; Worstell, Bruce B.

2003-01-01

The net ecosystem exchange (NEE) of carbon flux can be partitioned into gross primary productivity (GPP) and respiration (R). The contribution of remote sensing and modeling holds the potential to predict these components and map them spatially and temporally. This has obvious utility to quantify carbon sink and source relationships and to identify improved land management strategies for optimizing carbon sequestration. The objective of our study was to evaluate prediction of 14-day average daytime CO2 fluxes (Fday) and nighttime CO2 fluxes (Rn) using remote sensing and other data. Fday and Rnwere measured with a Bowen ratio–energy balance (BREB) technique in a sagebrush (Artemisia spp.)–steppe ecosystem in northeast Idaho, USA, during 1996–1999. Micrometeorological variables aggregated across 14-day periods and time-integrated Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (iNDVI) were determined during four growing seasons (1996–1999) and used to predict Fday and Rn. We found that iNDVI was a strong predictor of Fday(R2=0.79, n=66, P<0.0001). Inclusion of evapotranspiration in the predictive equation led to improved predictions of Fday (R2=0.82, n=66, P<0.0001). Crossvalidation indicated that regression tree predictions of Fday were prone to overfitting and that linear regression models were more robust. Multiple regression and regression tree models predicted Rn quite well (R2=0.75–0.77, n=66) with the regression tree model being slightly more robust in crossvalidation. Temporal mapping of Fday and Rn is possible with these techniques and would allow the assessment of NEE in sagebrush–steppe ecosystems. Simulations of periodic Fday measurements, as might be provided by a mobile flux tower, indicated that such measurements could be used in combination with iNDVI to accurately predict Fday. These periodic measurements could maximize the utility of expensive flux towers for evaluating various carbon management strategies, carbon certification, and validation and calibration of carbon flux models.

Calibration of remotely sensed, coarse resolution NDVI to CO2 fluxes in a sagebrush-steppe ecosystem

USGS Publications Warehouse

Wylie, B.K.; Johnson, D.A.; Laca, Emilio; Saliendra, Nicanor Z.; Gilmanov, T.G.; Reed, B.C.; Tieszen, L.L.; Worstell, B.B.

2003-01-01

The net ecosystem exchange (NEE) of carbon flux can be partitioned into gross primary productivity (GPP) and respiration (R). The contribution of remote sensing and modeling holds the potential to predict these components and map them spatially and temporally. This has obvious utility to quantify carbon sink and source relationships and to identify improved land management strategies for optimizing carbon sequestration. The objective of our study was to evaluate prediction of 14-day average daytime CO2 fluxes (Fday) and nighttime CO2 fluxes (Rn) using remote sensing and other data. Fday and Rn were measured with a Bowen ratio-energy balance (BREB) technique in a sagebrush (Artemisia spp.)-steppe ecosystem in northeast Idaho, USA, during 1996-1999. Micrometeorological variables aggregated across 14-day periods and time-integrated Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (iNDVI) were determined during four growing seasons (1996-1999) and used to predict Fday and Rn. We found that iNDVI was a strong predictor of Fday (R2 = 0.79, n = 66, P < 0.0001). Inclusion of evapotranspiration in the predictive equation led to improved predictions of Fday (R2= 0.82, n = 66, P < 0.0001). Crossvalidation indicated that regression tree predictions of Fday were prone to overfitting and that linear regression models were more robust. Multiple regression and regression tree models predicted Rn quite well (R2 = 0.75-0.77, n = 66) with the regression tree model being slightly more robust in crossvalidation. Temporal mapping of Fday and Rn is possible with these techniques and would allow the assessment of NEE in sagebrush-steppe ecosystems. Simulations of periodic Fday measurements, as might be provided by a mobile flux tower, indicated that such measurements could be used in combination with iNDVI to accurately predict Fday. These periodic measurements could maximize the utility of expensive flux towers for evaluating various carbon management strategies, carbon certification, and validation and calibration of carbon flux models. ?? 2003 Elsevier Science Inc. All rights reserved.

To BECCS or Not To BECCS: A Question of Method

NASA Astrophysics Data System (ADS)

DeCicco, J. M.

2017-12-01

Bioenergy with carbon capture and storage (BECCS) is seen as an important option in many climate stabilization scenarios. Limited demonstrations are underway, including a system that captures and sequesters the fermentation CO2 from ethanol production. However, its net CO2 emissions are uncertain for reasons related to both system characteristics and methodological issues. As for bioenergy in general, evaluations draw on both ecological and engineering methods. It is informative to apply different methods using available data for demonstration systems in comparison to related bioenergy systems. To do so, this paper examines a case study BECCS system and addresses questions regarding the utilization of terrestrial carbon, biomass sustainability and the implications for scalability. The analysis examines four systems, all utilizing the same land area, using two methods. The cases are: A) a crop system without either biofuel production or CCS; B) a biofuel production system without CCS; C) biofuel system with CCS, i.e., the BECCS case, and D) a crop system without biofuel production or CCS but with crop residue removal and conversion to a stable char. In cases A and D, the delivered fuel is fossil-based; in cases B and C the fuel is biomass-based. The first method is LCA, involving steady-flow modeling of systems over a defined lifecycle, following current practice as seen in the attributional LCA component of California's Low-Carbon Fuel Standard (LCFS). The second method involves spatially and temporally explicit analysis, reflecting the dynamics of carbon exchanges with the atmosphere. Although parameters are calibrated to the California LCFS LCA model, simplified spreadsheet modeling is used to maximize transparency while highlighting assumptions that most influence the results. The analysis reveals distinctly different pictures of net CO2 emissions for the cases examined, with the dynamic method painting a less optimistic picture of the BECCS system than the LCA method. Differences in results are traced to differing representations of terrestrial carbon exchanges and associated modeling assumptions. We conclude with suggestions for future work on project- and program-scale carbon accounting methods and the need for caution in advancing BECCS before such methods are better validated.

The adsorption of pharmaceutically active compounds from aqueous solutions onto activated carbons.

PubMed

Rakić, Vesna; Rac, Vladislav; Krmar, Marija; Otman, Otman; Auroux, Aline

2015-01-23

In this study, the adsorption of pharmaceutically active compounds - salicylic acid, acetylsalicylic acid, atenolol and diclofenac-Na onto activated carbons has been studied. Three different commercial activated carbons, possessing ∼650, 900 or 1500m(2)g(-1) surface areas were used as solid adsorbents. These materials were fully characterized - their textural, surface features and points of zero charge have been determined. The adsorption was studied from aqueous solutions at 303K using batch adsorption experiments and titration microcalorimetry, which was employed in order to obtain the heats evolved as a result of adsorption. The maximal adsorption capacities of investigated solids for all target pharmaceuticals are in the range of 10(-4)molg(-1). The obtained maximal retention capacities are correlated with the textural properties of applied activated carbon. The roles of acid/base features of activated carbons and of molecular structures of adsorbate molecules have been discussed. The obtained results enabled to estimate the possibility to use the activated carbons in the removal of pharmaceuticals by adsorption. Copyright © 2014 Elsevier B.V. All rights reserved.

Adapting an IPCC-Compliant Full Forest Carbon Accounting Model to Determine the Effects of Different Forest Management Strategies in California

NASA Astrophysics Data System (ADS)

Starrs, C.; Stewart, W.; Potts, M. D.

2016-12-01

As California experiences increasing rates of disturbance events such as wildfire, drought, and insect outbreaks, understanding how different management strategies affect long-term forest carbon stock changes in the forest and in harvested wood products used by society will be key to determining strategies to best maximize forest-related carbon sequestration in the future. California's forest area is roughly evenly split across three ownership types: private timberlands, National Forest timberlands, and reserved forests. Forest management strategies in California generally vary by these ownerships; management in reserved lands sequesters carbon within the forest (i.e. leaves wood in the forest), while on private and National Forest timberlands a significant amount of wood is removed from the forest and converted to harvested wood products. The Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) is an IPCC-compliant full forest carbon accounting model developed for use in Canada that has been adapted for use in other countries. Changes in natural disturbances in the forest and technological innovation in the use of harvested wood products could substantially alter future carbon trajectories of forests under different management regimes. A key advantage of the CBM-CFS3 model is that in addition to tracking live tree, dead tree, and dead organic matter (DOM) carbon pools in the forest, it also tracks carbon stock changes in harvested wood products. We calibrated the CBM-CFS3 model with US Forest Service Forest Inventory and Analysis (FIA) data for seven forest types across three ownership types to predict carbon stock changes under different natural disturbance and harvested wood product utilization futures. Our results illustrate the importance of using a tractable model that can integrate future changes in forest carbon cycling to keep pace with our changing climate and usage of wood products.

Carbon source-sink limitations differ between two species with contrasting growth strategies.

PubMed

Burnett, Angela C; Rogers, Alistair; Rees, Mark; Osborne, Colin P

2016-11-01

Understanding how carbon source and sink strengths limit plant growth is a critical knowledge gap that hinders efforts to maximize crop yield. We investigated how differences in growth rate arise from source-sink limitations, using a model system comparing a fast-growing domesticated annual barley (Hordeum vulgare cv. NFC Tipple) with a slow-growing wild perennial relative (Hordeum bulbosum). Source strength was manipulated by growing plants at sub-ambient and elevated CO 2 concentrations ([CO 2 ]). Limitations on vegetative growth imposed by source and sink were diagnosed by measuring relative growth rate, developmental plasticity, photosynthesis and major carbon and nitrogen metabolite pools. Growth was sink limited in the annual but source limited in the perennial. RGR and carbon acquisition were higher in the annual, but photosynthesis responded weakly to elevated [CO 2 ] indicating that source strength was near maximal at current [CO 2 ]. In contrast, photosynthetic rate and sink development responded strongly to elevated [CO 2 ] in the perennial, indicating significant source limitation. Sink limitation was avoided in the perennial by high sink plasticity: a marked increase in tillering and root:shoot ratio at elevated [CO 2 ], and lower non-structural carbohydrate accumulation. Alleviating sink limitation during vegetative development could be important for maximizing growth of elite cereals under future elevated [CO 2 ]. © 2016 John Wiley & Sons Ltd.

Staged heating by oxidation of carbonaceous material

DOEpatents

Knell, Everett W.; Green, Norman W.

1978-01-31

A carbonaceous material is pyrolyzed in the presence of a particulate source of heat obtained by the partial oxidation of a carbon containing solid residue of the carbonaceous material. The heat obtained from the oxidation of the carbon containing solid residue is maximized by preheating the carbon containing solid residue with a hot gas stream obtained by oxidizing the gaseous combustion products of the carbon containing solid residue.

Aging and loss decision making: increased risk aversion and decreased use of maximizing information, with correlated rationality and value maximization

PubMed Central

Kurnianingsih, Yoanna A.; Sim, Sam K. Y.; Chee, Michael W. L.; Mullette-Gillman, O’Dhaniel A.

2015-01-01

We investigated how adult aging specifically alters economic decision-making, focusing on examining alterations in uncertainty preferences (willingness to gamble) and choice strategies (what gamble information influences choices) within both the gains and losses domains. Within each domain, participants chose between certain monetary outcomes and gambles with uncertain outcomes. We examined preferences by quantifying how uncertainty modulates choice behavior as if altering the subjective valuation of gambles. We explored age-related preferences for two types of uncertainty, risk, and ambiguity. Additionally, we explored how aging may alter what information participants utilize to make their choices by comparing the relative utilization of maximizing and satisficing information types through a choice strategy metric. Maximizing information was the ratio of the expected value of the two options, while satisficing information was the probability of winning. We found age-related alterations of economic preferences within the losses domain, but no alterations within the gains domain. Older adults (OA; 61–80 years old) were significantly more uncertainty averse for both risky and ambiguous choices. OA also exhibited choice strategies with decreased use of maximizing information. Within OA, we found a significant correlation between risk preferences and choice strategy. This linkage between preferences and strategy appears to derive from a convergence to risk neutrality driven by greater use of the effortful maximizing strategy. As utility maximization and value maximization intersect at risk neutrality, this result suggests that OA are exhibiting a relationship between enhanced rationality and enhanced value maximization. While there was variability in economic decision-making measures within OA, these individual differences were unrelated to variability within examined measures of cognitive ability. Our results demonstrate that aging alters economic decision-making for losses through changes in both individual preferences and the strategies individuals employ. PMID:26029092

All-Iron Redox Flow Battery Tailored for Off-Grid Portable Applications.

PubMed

Tucker, Michael C; Phillips, Adam; Weber, Adam Z

2015-12-07

An all-iron redox flow battery is proposed and developed for end users without access to an electricity grid. The concept is a low-cost battery which the user assembles, discharges, and then disposes of the active materials. The design goals are: (1) minimize upfront cost, (2) maximize discharge energy, and (3) utilize non-toxic and environmentally benign materials. These are different goals than typically considered for electrochemical battery technology, which provides the opportunity for a novel solution. The selected materials are: low-carbon-steel negative electrode, paper separator, porous-carbon-paper positive electrode, and electrolyte solution containing 0.5 m Fe2 (SO4 )3 active material and 1.2 m NaCl supporting electrolyte. With these materials, an average power density around 20 mW cm(-2) and a maximum energy density of 11.5 Wh L(-1) are achieved. A simple cost model indicates the consumable materials cost US$6.45 per kWh(-1) , or only US$0.034 per mobile phone charge. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

All-Iron Redox Flow Battery Tailored for Off-Grid Portable Applications

DOE PAGES

Tucker, Michael C.; Phillips, Adam; Weber, Adam Z.

2015-11-20

We proposed and developed an all-iron redox flow battery for end users without access to an electricity grid. The concept is a low-cost battery which the user assembles, discharges, and then disposes of the active materials. Our design goals are: (1) minimize upfront cost, (2) maximize discharge energy, and (3) utilize non-toxic and environmentally benign materials. These are different goals than typically considered for electrochemical battery technology, which provides the opportunity for a novel solution. The selected materials are: low-carbon-steel negative electrode, paper separator, porous-carbon-paper positive electrode, and electrolyte solution containing 0.5 m Fe 2 (SO 4 ) 3 activemore » material and 1.2 m NaCl supporting electrolyte. Furthermore, with these materials, an average power density around 20 mW cm -2 and a maximum energy density of 11.5 Wh L -1 are achieved. A simple cost model indicates the consumable materials cost US$6.45 per kWh -1 , or only US$0.034 per mobile phone charge.« less

Carbon source and energy harvesting optimization in solid anolyte microbial fuel cells

NASA Astrophysics Data System (ADS)

Adekunle, Ademola; Raghavan, Vijaya; Tartakovsky, Boris

2017-07-01

This work investigates the application of a solid anolyte microbial fuel cell (saMFC) as a long-lasting source of electricity for powering electronic devices. Broadly available biodegradable materials such as humus, cattle manure, peat moss, and sawdust are evaluated as solid anolytes. The initial comparison shows significantly higher power production in the saMFC operated using humus as compared to other solid anolytes. At the same time, power production in the humus-based saMFC is found to decline after about 40 days of operation, while the sawdust MFC demonstrates stable performance over the test period. Following this initial comparison, a combined humus - sawdust anolyte is developed to increase saMFC life span. The optimized saMFC demonstrates stable power production for over nine months. Furthermore, power production in the saMFC is maximized by using an intermittent connection to an electrical load (on/off operation) and optimizing the connection/disconnection times. These results demonstrate the feasibility of utilizing solid anolytes for developing inexpensive and long-lasting biobatteries operated on renewable carbon sources.

A review: Potential and challenges of biologically activated carbon to remove natural organic matter in drinking water purification process.

PubMed

Korotta-Gamage, Shashika Madushi; Sathasivan, Arumugam

2017-01-01

The use of biologically activated carbon (BAC) in drinking water purification is reviewed. In the past BAC is seen mostly as a polishing treatment. However, BAC has the potential to provide solution to recent challenges faced by water utilities arising from change in natural organic matter (NOM) composition in drinking water sources - increased NOM concentration with a larger fraction of hydrophilic compounds and ever increasing trace level organic pollutants. Hydrophilic NOM is not removed by traditional coagulation process and causes bacterial regrowth and increases disinfection by-products (DBPs) formation during disinfection. BAC can offer many advantages by removing hydrophilic fraction and many toxic and endocrine compounds which are not otherwise removed. BAC can also aid the other downstream processes if used as a pre-treatment. Major drawback of BAC was longer empty bed contact time (EBCT) required for an effective NOM removal. This critical review analyses the strategies that have been adopted to enhance the biological activity of the carbon by operational means and summarises the surface modification methods. To maximize the benefit of the BAC, a rethink of current treatment plant configuration is proposed. If the process can be expedited and adopted appropriately, BAC can solve many of the current problems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coupling a Supercritical Carbon Dioxide Brayton Cycle to a Helium-Cooled Reactor.

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

Middleton, Bobby; Pasch, James Jay; Kruizenga, Alan Michael

2016-01-01

This report outlines the thermodynamics of a supercritical carbon dioxide (sCO 2) recompression closed Brayton cycle (RCBC) coupled to a Helium-cooled nuclear reactor. The baseline reactor design for the study is the AREVA High Temperature Gas-Cooled Reactor (HTGR). Using the AREVA HTGR nominal operating parameters, an initial thermodynamic study was performed using Sandia's deterministic RCBC analysis program. Utilizing the output of the RCBC thermodynamic analysis, preliminary values of reactor power and of Helium flow rate through the reactor were calculated in Sandia's HelCO 2 code. Some research regarding materials requirements was then conducted to determine aspects of corrosion related tomore » both Helium and to sCO 2 , as well as some mechanical considerations for pressures and temperatures that will be seen by the piping and other components. This analysis resulted in a list of materials-related research items that need to be conducted in the future. A short assessment of dry heat rejection advantages of sCO 2> Brayton cycles was also included. This assessment lists some items that should be investigated in the future to better understand how sCO 2 Brayton cycles and nuclear can maximally contribute to optimizing the water efficiency of carbon free power generation« less

Carbon Mineralization by Aqueous Precipitation for Beneficial Use of CO2 from Flue Gas

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

Devenney, Martin; Gilliam, Ryan; Seeker, Randy

2013-08-01

The objective of this project is to demonstrate an innovative process to mineralize CO2 from flue gas directly to reactive carbonates and maximize the value and versatility of its beneficial use products. The program scope includes the design, construction, and testing of a CO2 Conversion to Material Products (CCMP) Pilot Demonstration Plant utilizing CO2 from the flue gas of a power production facility in Moss Landing, CA. This topical report covers Subphase 2a which is the design phase of pilot demonstration subsystems. Materials of construction have been selected and proven in both lab scale and prototype testing to be acceptablemore » for the reagent conditions of interest. The target application for the reactive carbonate material has been selected based upon small-scale feasibility studies and the design of a continuous fiber board production line has been completed. The electrochemical cell architecture and components have been selected based upon both lab scale and prototype testing. The appropriate quality control and diagnostic techniques have been developed and tested along with the required instrumentation and controls. Finally the demonstrate site infrastructure, NEPA categorical exclusion, and permitting is all ready for the construction and installation of the new units and upgrades.« less

Application of metabolic controls for the maximization of lipid production in semicontinuous fermentation.

PubMed

Xu, Jingyang; Liu, Nian; Qiao, Kangjian; Vogg, Sebastian; Stephanopoulos, Gregory

2017-07-03

Acetic acid can be generated through syngas fermentation, lignocellulosic biomass degradation, and organic waste anaerobic digestion. Microbial conversion of acetate into triacylglycerols for biofuel production has many advantages, including low-cost or even negative-cost feedstock and environmental benefits. The main issue stems from the dilute nature of acetate produced in such systems, which is costly to be processed on an industrial scale. To tackle this problem, we established an efficient bioprocess for converting dilute acetate into lipids, using the oleaginous yeast Yarrowia lipolytica in a semicontinuous system. The implemented design used low-strength acetic acid in both salt and acid forms as carbon substrate and a cross-filtration module for cell recycling. Feed controls for acetic acid and nitrogen based on metabolic models and online measurement of the respiratory quotient were used. The optimized process was able to sustain high-density cell culture using acetic acid of only 3% and achieved a lipid titer, yield, and productivity of 115 g/L, 0.16 g/g, and 0.8 g⋅L -1 ⋅h -1 , respectively. No carbon substrate was detected in the effluent stream, indicating complete utilization of acetate. These results represent a more than twofold increase in lipid production metrics compared with the current best-performing results using concentrated acetic acid as carbon feed.

Foxtail Millet [Setaria italica (L.) Beauv.] Grown under Low Nitrogen Shows a Smaller Root System, Enhanced Biomass Accumulation, and Nitrate Transporter Expression.

PubMed

Nadeem, Faisal; Ahmad, Zeeshan; Wang, Ruifeng; Han, Jienan; Shen, Qi; Chang, Feiran; Diao, Xianmin; Zhang, Fusuo; Li, Xuexian

2018-01-01

Foxtail millet (FM) [ Setaria italica (L.) Beauv.] is a grain and forage crop well adapted to nutrient-poor soils. To date little is known how FM adapts to low nitrogen (LN) at the morphological, physiological, and molecular levels. Using the FM variety Yugu1, we found that LN led to lower chlorophyll contents and N concentrations, and higher root/shoot and C/N ratios and N utilization efficiencies under hydroponic culture. Importantly, enhanced biomass accumulation in the root under LN was in contrast to a smaller root system, as indicated by significant decreases in total root length; crown root number and length; and lateral root number, length, and density. Enhanced carbon allocation toward the root was rather for significant increases in average diameter of the LN root, potentially favorable for wider xylem vessels or other anatomical alterations facilitating nutrient transport. Lower levels of IAA and CKs were consistent with a smaller root system and higher levels of GA may promote root thickening under LN. Further, up-regulation of SiNRT1.1, SiNRT2.1, and SiNAR2.1 expression and nitrate influx in the root and that of SiNRT1.11 and SiNRT1.12 expression in the shoot probably favored nitrate uptake and remobilization as a whole. Lastly, more soluble proteins accumulated in the N-deficient root likely as a result of increases of N utilization efficiencies. Such "excessive" protein-N was possibly available for shoot delivery. Thus, FM may preferentially transport carbon toward the root facilitating root thickening/nutrient transport and allocate N toward the shoot maximizing photosynthesis/carbon fixation as a primary adaptive strategy to N limitation.

Catabolite repression by intracellular succinate in Campylobacter jejuni

USDA-ARS?s Scientific Manuscript database

Bacteria have evolved different mechanisms to catabolize carbon sources from a mixture of nutrients. They first consume their preferred carbon source, before others are used. Regulatory mechanisms adapt the metabolism accordingly to maximize growth and to outcompete other organisms. The human patho...

Changes of glucose utilization by erythrocytes, lactic acid concentration in the serum and blood cells, and haematocrit value during one hour rest after maximal effort in individuals differing in physical efficiency.

PubMed

Tomasik, M

1982-01-01

Glucose utilization by the erythrocytes, lactic acid concentration in the blood and erythrocytes, and haematocrit value were determined before exercise and during one hour rest following maximal exercise in 97 individuals of either sex differing in physical efficiency. In the investigations reported by the author individuals with strikingly high physical fitness performed maximal work one-third greater than that performed by individuals with medium fitness. The serum concentration of lactic acid was in all individuals above the resting value still after 60 minutes of rest. On the other hand, this concentration returned to the normal level in the erythrocytes but only in individuals with strikingly high efficiency. Glucose utilization by the erythrocytes during the restitution period was highest immediately after the exercise in all studied individuals and showed a tendency for more rapid return to resting values again in individuals with highest efficiency. The investigation of very efficient individuals repeated twice demonstrated greater utilization of glucose by the erythrocytes at the time of greater maximal exercise. This was associated with greater lactic acid concentration in the serum and erythrocytes throughout the whole one-hour rest period. The observed facts suggest an active participation of erythrocytes in the process of adaptation of the organism to exercise.

Equilibrium in a Production Economy

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

Chiarolla, Maria B., E-mail: maria.chiarolla@uniroma1.it; Haussmann, Ulrich G., E-mail: uhaus@math.ubc.ca

2011-06-15

Consider a closed production-consumption economy with multiple agents and multiple resources. The resources are used to produce the consumption good. The agents derive utility from holding resources as well as consuming the good produced. They aim to maximize their utility while the manager of the production facility aims to maximize profits. With the aid of a representative agent (who has a multivariable utility function) it is shown that an Arrow-Debreu equilibrium exists. In so doing we establish technical results that will be used to solve the stochastic dynamic problem (a case with infinite dimensional commodity space so the General Equilibriummore » Theory does not apply) elsewhere.« less

Limit order placement as an utility maximization problem and the origin of power law distribution of limit order prices

NASA Astrophysics Data System (ADS)

Lillo, F.

2007-02-01

I consider the problem of the optimal limit order price of a financial asset in the framework of the maximization of the utility function of the investor. The analytical solution of the problem gives insight on the origin of the recently empirically observed power law distribution of limit order prices. In the framework of the model, the most likely proximate cause of this power law is a power law heterogeneity of traders' investment time horizons.

Underground Coal Gasification Research Program near Hanna, Carbon County, Wyoming: Environmental impact assessment

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

Not Available

In the fall of 1972, the Laramie Energy Research Center initiated an in situ coal gasification experiment in Hanna, Wyoming. The objective was to test the feasibility of underground gasification in a deep, thick seam of western subbituminous coal and, if feasible, to maximize gas heating value while sustaining stable gas production rates and achieving a high coal utilization efficiency. The coal seam was ignited on March 28, 1973, in a 30-foot seam 400 feet deep. The ''burn'' was maintained for a year, until March 22, 1974, when air injection was stopped. The combustion zone was extinguished by the naturalmore » influx of seam water in approximately three months. This report discusses the environmental inpacts of this program on the area and provides details of the program. 13 refs., 7 figs., 11 tabs.« less

Multifunctional carbon nanoelectrodes fabricated by focused ion beam milling.

PubMed

Thakar, Rahul; Weber, Anna E; Morris, Celeste A; Baker, Lane A

2013-10-21

We report a strategy for fabrication of sub-micron, multifunctional carbon electrodes and application of these electrodes as probes for scanning electrochemical microscopy (SECM) and scanning ion conductance microscopy (SICM). The fabrication process utilized chemical vapor deposition of parylene, followed by thermal pyrolysis to form conductive carbon and then further deposition of parylene to form an insulation layer. To achieve well-defined electrode geometries, two methods of electrode exposure were utilized. In the first method, carbon probes were masked in polydimethylsiloxane (PDMS) to obtain a cone-shaped electrode. In the second method, the electrode area was exposed via milling with a focused ion beam (FIB) to reveal a carbon ring electrode, carbon ring/platinum disk electrode, or carbon ring/nanopore electrode. Carbon electrodes were batch fabricated (~35/batch) through the vapor deposition process and were characterized with scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and cyclic voltammetry (CV) measurements. Additionally, Raman spectroscopy was utilized to examine the effects of Ga(+) ion implantation, a result of FIB milling. Constant-height, feedback mode SECM was performed with conical carbon electrodes and carbon ring electrodes. We demonstrate the utility of carbon ring/nanopore electrodes with SECM-SICM to simultaneously collect topography, ion current and electrochemical current images. In addition, carbon ring/nanopore electrodes were utilized in substrate generation/tip collection (SG/TC) SECM. In SG/TC SECM, localized delivery of redox molecules affords a higher resolution, than when the redox molecules are present in the bath solution. Multifunctional geometries of carbon electrode probes will find utility in electroanalytical applications, in general, and more specifically with electrochemical microscopy as discussed herein.

A mobile light source for carbon/nitrogen cameras

NASA Astrophysics Data System (ADS)

Trower, W. P.; Karev, A. I.; Melekhin, V. N.; Shvedunov, V. I.; Sobenin, N. P.

1995-05-01

The pulsed light source for carbon/nitrogen cameras developed to image concealed narcotics/explosives is described. This race-track microtron will produce 40 mA pulses of 70 MeV electrons, have minimal size and weight, and maximal ruggedness and reliability, so that it can be transported on a truck.

Influence of activated carbon characteristics on toluene and hexane adsorption: Application of surface response methodology

NASA Astrophysics Data System (ADS)

Izquierdo, Mª Teresa; de Yuso, Alicia Martínez; Valenciano, Raquel; Rubio, Begoña; Pino, Mª Rosa

2013-01-01

The objective of this study was to evaluate the adsorption capacity of toluene and hexane over activated carbons prepared according an experimental design, considering as variables the activation temperature, the impregnation ratio and the activation time. The response surface methodology was applied to optimize the adsorption capacity of the carbons regarding the preparation conditions that determine the physicochemical characteristics of the activated carbons. The methodology of preparation produced activated carbons with surface areas and micropore volumes as high as 1128 m2/g and 0.52 cm3/g, respectively. Moreover, the activated carbons exhibit mesoporosity, ranging from 64.6% to 89.1% the percentage of microporosity. The surface chemistry was characterized by TPD, FTIR and acid-base titration obtaining different values of surface groups from the different techniques because the limitation of each technique, but obtaining similar trends for the activated carbons studied. The exhaustive characterization of the activated carbons allows to state that the measured surface area does not explain the adsorption capacity for either toluene or n-hexane. On the other hand, the surface chemistry does not explain the adsorption results either. A compromise between physical and chemical characteristics can be obtained from the appropriate activation conditions, and the response surface methodology gives the optimal activated carbon to maximize adsorption capacity. Low activation temperature, intermediate impregnation ratio lead to high toluene and n-hexane adsorption capacities depending on the activation time, which a determining factor to maximize toluene adsorption.

Differences in carbon source utilization of Salmonella Oranienburg and Saintpaul isolated from river water.

PubMed

Medrano-Félix, Andrés; Estrada-Acosta, Mitzi; Peraza-Garay, Felipe; Castro-Del Campo, Nohelia; Martínez-Urtaza, Jaime; Chaidez, Cristóbal

2017-08-01

Long-term exposure to river water by non-indigenous micro-organisms such as Salmonella may affect metabolic adaptation to carbon sources. This study was conducted to determine differences in carbon source utilization of Salmonella Oranienburg and Salmonella Saintpaul (isolated from tropical river water) as well as the control strain Salmonella Typhimurium exposed to laboratory, river water, and host cells (Hep-2 cell line) growth conditions. Results showed that Salmonella Oranienburg and Salmonella Saintpaul showed better ability for carbon source utilization under the three growth conditions evaluated; however, S. Oranienburg showed the fastest and highest utilization on different carbon sources, including D-Glucosaminic acid, N-acetyl-D-Glucosamine, Glucose-1-phosphate, and D-Galactonic acid, while Salmonella Saintpaul and S. Typhimurium showed a limited utilization of carbon sources. In conclusion, this study suggests that environmental Salmonella strains show better survival and preconditioning abilities to external environments than the control strain based on their plasticity on diverse carbon sources use.

Grassland biodiversity can pay.

PubMed

Binder, Seth; Isbell, Forest; Polasky, Stephen; Catford, Jane A; Tilman, David

2018-04-10

The biodiversity-ecosystem functioning (BEF) literature provides strong evidence of the biophysical basis for the potential profitability of greater diversity but does not address questions of optimal management. BEF studies typically focus on the ecosystem outputs produced by randomly assembled communities that only differ in their biodiversity levels, measured by indices such as species richness. Landholders, however, do not randomly select species to plant; they choose particular species that collectively maximize profits. As such, their interest is not in comparing the average performance of randomly assembled communities at each level of biodiversity but rather comparing the best-performing communities at each diversity level. Assessing the best-performing mixture requires detailed accounting of species' identities and relative abundances. It also requires accounting for the financial cost of individual species' seeds, and the economic value of changes in the quality, quantity, and variability of the species' collective output-something that existing multifunctionality indices fail to do. This study presents an assessment approach that integrates the relevant factors into a single, coherent framework. It uses ecological production functions to inform an economic model consistent with the utility-maximizing decisions of a potentially risk-averse private landowner. We demonstrate the salience and applicability of the framework using data from an experimental grassland to estimate production relationships for hay and carbon storage. For that case, our results suggest that even a risk-neutral, profit-maximizing landowner would favor a highly diverse mix of species, with optimal species richness falling between the low levels currently found in commercial grasslands and the high levels found in natural grasslands.

Rapid Removal of Atmospheric CO2 by Urban Soils.

PubMed

Washbourne, Carla-Leanne; Lopez-Capel, Elisa; Renforth, Phil; Ascough, Philippa L; Manning, David A C

2015-05-05

The measured calcium carbonate content of soils to a depth of 100 mm at a large urban development site has increased over 18 months at a rate that corresponds to the sequestration of 85 t of CO2/ha (8.5 kg of CO2 m(-2)) annually. This is a consequence of rapid weathering of calcium silicate and hydroxide minerals derived from the demolition of concrete structures, which releases Ca that combines with CO2 ultimately derived from the atmosphere, precipitating as calcite. Stable isotope data confirm an atmospheric origin for carbonate carbon, and 14C dating indicates the predominance of modern carbon in the pedogenic calcite. Trial pits show that carbonation extends to depths of ≥1 m. Work at other sites shows that the occurrence of pedogenic carbonates is widespread in artificially created urban soils containing Ca and Mg silicate minerals. Appropriate management of fewer than 12000 ha of urban land to maximize calcite precipitation has the potential to remove 1 million t of CO2 from the atmosphere annually. The maximal global potential is estimated to be approximately 700-1200 Mt of CO2 per year (representing 2.0-3.7% of total emissions from fossil fuel combustion) based on current rates of production of industry-derived Ca- and Mg-bearing materials.

Series-Bosch Technology for Oxygen Recovery During Lunar or Martian Surface Missions

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, J. Matthew; Rabenberg, Ellen; Stanley, Christine M.; Edmunson, Jennifer; Alleman, James E.; Chen, Kevin; Dumez, Sam

2014-01-01

Long-duration surface missions to the Moon or Mars will require life support systems that maximize resource recovery to minimize resupply from Earth. To address this need, NASA previously proposed a Series-Bosch (S-Bosch) oxygen recovery system, based on the Bosch process, which can theoretically recover 100% of the oxygen from metabolic carbon dioxide. Bosch processes have the added benefits of the potential to recover oxygen from atmospheric carbon dioxide and the use of regolith materials as catalysts, thereby eliminating the need for catalyst resupply from Earth. In 2012, NASA completed an initial design for an S-Bosch development test stand that incorporates two catalytic reactors in series including a Reverse Water-Gas Shift (RWGS) Reactor and a Carbon Formation Reactor (CFR). In 2013, fabrication of system components, with the exception of a CFR, and assembly of the test stand was initiated. Stand-alone testing of the RWGS reactor was completed to compare performance with design models. Continued testing of Lunar and Martian regolith simulants provided sufficient data to design a CFR intended to utilize these materials as catalysts. Finally, a study was conducted to explore the possibility of producing bricks from spent regolith catalysts. The results of initial demonstration testing of the RWGS reactor, results of continued catalyst performance testing of regolith simulants, and results of brick material properties testing are reported. Additionally, design considerations for a regolith-based CFR are discussed.

Series-Bosch Technology for Oxygen Recovery During Lunar or Martian Surface Missions

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, James M.; Stanley, Christine; Edmunson, Jennifer; Dumez, Samuel; Chen, Kevin; Alleman, James E.

2014-01-01

Long-duration surface missions to the Moon or Mars will require life support systems that maximize resource recovery to minimize resupply from Earth. To address this need, NASA previously proposed a Series-Bosch (S-Bosch) oxygen recovery system, based on the Bosch process, which can theoretically recover 100% of the oxygen from metabolic carbon dioxide. Bosch processes have the added benefits of the potential to recover oxygen from atmospheric carbon dioxide and the use of regolith materials as catalysts, thereby eliminating the need for catalyst resupply from Earth. In 2012, NASA completed an initial design for an S-Bosch development test stand that incorporates two catalytic reactors in series including a Reverse Water-Gas Shift (RWGS) Reactor and a Carbon Formation Reactor (CFR). In 2013, fabrication of system components, with the exception of a CFR, and assembly of the test stand was initiated. Stand-alone testing of the RWGS reactor was completed to compare performance with design models. Continued testing of Lunar and Martian regolith simulants provided sufficient data to design a CFR intended to utilize these materials as catalysts. Finally, a study was conducted to explore the possibility of producing bricks from spend regolith catalysts. The results of initial demonstration testing of the RWGS reactor, results of continued catalyst performance testing of regolith simulants, and results of brick material properties testing are reported. Additionally, design considerations for a regolith-based CFR are discussed.

The energetic and carbon economic origins of leaf thermoregulation.

PubMed

Michaletz, Sean T; Weiser, Michael D; McDowell, Nate G; Zhou, Jizhong; Kaspari, Michael; Helliker, Brent R; Enquist, Brian J

2016-08-22

Leaf thermoregulation has been documented in a handful of studies, but the generality and origins of this pattern are unclear. We suggest that leaf thermoregulation is widespread in both space and time, and originates from the optimization of leaf traits to maximize leaf carbon gain across and within variable environments. Here we use global data for leaf temperatures, traits and photosynthesis to evaluate predictions from a novel theory of thermoregulation that synthesizes energy budget and carbon economics theories. Our results reveal that variation in leaf temperatures and physiological performance are tightly linked to leaf traits and carbon economics. The theory, parameterized with global averaged leaf traits and microclimate, predicts a moderate level of leaf thermoregulation across a broad air temperature gradient. These predictions are supported by independent data for diverse taxa spanning a global air temperature range of ∼60 °C. Moreover, our theory predicts that net carbon assimilation can be maximized by means of a trade-off between leaf thermal stability and photosynthetic stability. This prediction is supported by globally distributed data for leaf thermal and photosynthetic traits. Our results demonstrate that the temperatures of plant tissues, and not just air, are vital to developing more accurate Earth system models.

Optimum electric utility spot price determinations for small power producing facilities operating under PURPA provisions

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

Ghoudjehbaklou, H.; Puttgen, H.B.

This paper outlines an optimum spot price determination procedure in the general context of the Public Utility Regulatory Policies Act, PURPA, provisions. PURPA stipulates that local utilities must offer to purchase all available excess electric energy from Qualifying Facilities, QF, at fair market prices. As a direct consequence of these PURPA regulations, a growing number of owners are installing power producing facilities and optimize their operational schedules to minimize their utility related costs or, in some cases, actually maximize their revenues from energy sales to the local utility. In turn, the utility strives to use spot prices which maximize itsmore » revenues from any given Small Power Producing Facility, SPPF, a schedule while respecting the general regulatory and contractual framework. the proposed optimum spot price determination procedure fully models the SPPF operation, it enforces the contractual and regulatory restrictions, and it ensures the uniqueness of the optimum SPPF schedule.« less

Optimum electric utility spot price determinations for small power producing facilities operating under PURPA provisions

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

Ghoudjehbaklou, H.; Puttgen, H.B.

The present paper outlines an optimum spot price determination procedure in the general context of the Public Utility Regulatory Policies Act, PURPA, provisions. PURPA stipulates that local utilities must offer to purchase all available excess electric energy from Qualifying Facilities, QF, at fair market prices. As a direct consequence of these PURPA regulations, a growing number of owners are installing power producing facilities and optimize their operational schedules to minimize their utility related costs or, in some cases, actually maximize their revenues from energy sales to the local utility. In turn, the utility will strive to use spot prices whichmore » maximize its revenues from any given Small Power Producing Facility, SPPF, schedule while respecting the general regulatory and contractual framework. The proposed optimum spot price determination procedure fully models the SPPF operation, it enforces the contractual and regulatory restrictions, and it ensures the uniqueness of the optimum SPPF schedule.« less

Designing Agent Collectives For Systems With Markovian Dynamics

NASA Technical Reports Server (NTRS)

Wolpert, David H.; Lawson, John W.

2004-01-01

The Collective Intelligence (COIN) framework concerns the design of collectives of agents so that as those agents strive to maximize their individual utility functions, their interaction causes a provided world utility function concerning the entire collective to be also maximized. Here we show how to extend that framework to scenarios having Markovian dynamics when no re-evolution of the system from counter-factual initial conditions (an often expensive calculation) is permitted. Our approach transforms the (time-extended) argument of each agent's utility function before evaluating that function. This transformation has benefits in scenarios not involving Markovian dynamics of an agent's utility function are observable. We investigate this transformation in simulations involving both hear and quadratic (nonlinear) dynamics. In addition, we find that a certain subset of these transformations, which result in utilities that have low opacity (analogous to having high signal to noise) but are not factored (analogous to not being incentive compatible), reliably improve performance over that arising with factored utilities. We also present a Taylor Series method for the fully general nonlinear case.

Demonstration of Robustness and Integrated Operation of a Series-Bosch System

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, Matthew J.; Stanley, Christine; Barnett, Bill; Junaedi, Christian; Vilekar, Saurabh A.; Ryan, Kent

2016-01-01

Manned missions beyond low Earth orbit will require highly robust, reliable, and maintainable life support systems that maximize recycling of water and oxygen. Bosch technology is one option to maximize oxygen recovery, in the form of water, from metabolically-produced carbon dioxide (CO2). A two stage approach to Bosch, called Series-Bosch, reduces metabolic CO2 with hydrogen (H2) to produce water and solid carbon using two reactors: a Reverse Water-Gas Shift (RWGS) reactor and a carbon formation (CF) reactor. Previous development efforts demonstrated the stand-alone performance of a NASA-designed RWGS reactor designed for robustness against carbon formation, two membrane separators intended to maximize single pass conversion of reactants, and a batch CF reactor with both transit and surface catalysts. In the past year, Precision Combustion, Inc. (PCI) developed and delivered a RWGS reactor for testing at NASA. The reactor design was based on their patented Microlith® technology and was first evaluated under a Phase I Small Business Innovative Research (SBIR) effort in 2010. The RWGS reactor was recently evaluated at NASA to compare its performance and operating conditions with NASA's RWGS reactor. The test results will be provided in this paper. Separately, in 2015, a semi-continuous CF reactor was designed and fabricated at NASA based on the results from batch CF reactor testing. The batch CF reactor and the semi-continuous CF reactor were individually integrated with an upstream RWGS reactor to demonstrate the system operation and to evaluate performance. Here, we compare the performance and robustness to carbon formation of both RWGS reactors. We report the results of the integrated operation of a Series-Bosch system and we discuss the technology readiness level.

Demonstration of Robustness and Integrated Operation of a Series-Bosch System

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, J. Matthew; Barnett, Bill; Stanley, Christine M.; Junaedi, Christian; Vilekar, Saurabh A.; Kent, Ryan

2016-01-01

Manned missions beyond low Earth orbit will require highly robust, reliable, and maintainable life support systems that maximize recycling of water and oxygen. Bosch technology is one option to maximize oxygen recovery, in the form of water, from metabolically-produced carbon dioxide (CO2). A two stage approach to Bosch, called Series-Bosch, reduces metabolic CO2 with hydrogen (H2) to produce water and solid carbon using two reactors: a Reverse Water-Gas Shift (RWGS) reactor and a carbon formation (CF) reactor. Previous development efforts demonstrated the stand-alone performance of a RWGS reactor containing Incofoam(TradeMark) catalyst and designed for robustness against carbon formation, two membrane separators intended to maximize single pass conversion of reactants, and a batch CF reactor with both transit and surface catalysts. In the past year, Precision Combustion, Inc. (PCI) developed and delivered a RWGS reactor for testing at NASA. The reactor design was based on their patented Microlith(TradeMark) technology and was first evaluated under a Phase I Small Business Innovative Research (SBIR) effort in 2010. The Microlith(TradeMark) RWGS reactor was recently evaluated at NASA to compare its performance and operating conditions with the Incofoam(TradeMark) RWGS reactor. Separately, in 2015, a fully integrated demonstration of an S-Bosch system was conducted. In an effort to mitigate risk, a second integrated test was conducted to evaluate the effect of membrane failure on a closed-loop Bosch system. Here, we report and discuss the performance and robustness to carbon formation of both RWGS reactors. We report the results of the integrated operation of a Series-Bosch system and we discuss the technology readiness level. 1

Integration and Improvement of Geophysical Root Biomass Measurements for Determining Carbon Credits

NASA Astrophysics Data System (ADS)

Boitet, J. I.

2013-12-01

Carbon trading schemes fundamentally rely on accurate subsurface carbon quantification in order for governing bodies to grant carbon credits inclusive of root biomass (What is Carbon Credit. 2013). Root biomass makes up a large chunk of the subsurface carbon and is difficult, labor intensive, and costly to measure. This paper stitches together the latest geophysical root measurement techniques into site-dependent recommendations for technique combinations and modifications that maximize large-scale root biomass measurement accuracy and efficiency. "Accuracy" is maximized when actual root biomass is closest to measured root biomass. "Efficiency" is maximized when time, labor, and cost of measurement is minimized. Several combinations have emerged which satisfy both criteria under different site conditions. Use of ground penetrating radar (GPR) and/or electrical resistivity tomography (ERT) allow for large tracts of land to be surveyed under appropriate conditions. Among other characteristics, GPR does best with detecting coarse roots in dry soil. ERT does best in detecting roots in moist soils, but is especially limited by electrode configuration (Mancuso, S. 2012). Integration of these two technologies into a baseline protocol based on site-specific characteristics, especially soil moisture and plants species heterogeneity, will drastically theoretically increase efficiency and accuracy of root biomass measurements. Modifications of current measurement protocols using these existing techniques will also theoretically lead to drastic improvements in both accuracy and efficiency. These modifications, such as efficient 3D imaging by adding an identical electrode array perpendicular to the first array used in the Pulled Array Continuous Electrical Profiling (PACEP) technique for ERT, should allow for more widespread application of these techniques for understanding root biomass. Where whole-site measurement is not feasible either due to financial, equipment, or physical limitations, measurements from randomly selected plots must be assumed representative of the entire system and scaled up. This scaling introduces error roughly inversely proportional to the number and size of plots measured. References Mancuso, S. (2012). Measuring roots: An updated approach Springer. What is carbon credit. (2013). Retrieved 7/20, 2013, from http://carbontradexchange.com/knowledge/what-is-carbon-credit

Modeling and optimization of proton-conducting solid oxide electrolysis cell: Conversion of CO2 into value-added products

NASA Astrophysics Data System (ADS)

Namwong, Lawit; Authayanun, Suthida; Saebea, Dang; Patcharavorachot, Yaneeporn; Arpornwichanop, Amornchai

2016-11-01

Proton-conducting solid oxide electrolysis cells (SOEC-H+) are a promising technology that can utilize carbon dioxide to produce syngas. In this work, a detailed electrochemical model was developed to predict the behavior of SOEC-H+ and to prove the assumption that the syngas is produced through a reversible water gas-shift (RWGS) reaction. The simulation results obtained from the model, which took into account all of the cell voltage losses (i.e., ohmic, activation, and concentration losses), were validated using experimental data to evaluate the unknown parameters. The developed model was employed to examine the structural and operational parameters. It is found that the cathode-supported SOEC-H+ is the best configuration because it requires the lowest cell potential. SOEC-H+ operated favorably at high temperatures and low pressures. Furthermore, the simulation results revealed that the optimal S/C molar ratio for syngas production, which can be used for methanol synthesis, is approximately 3.9 (at a constant temperature and pressure). The SOEC-H+ was optimized using a response surface methodology, which was used to determine the optimal operating conditions to minimize the cell potential and maximize the carbon dioxide flow rate.

Enhanced carbon monoxide utilization in methanation process

DOEpatents

Elek, Louis F.; Frost, Albert C.

1984-01-01

Carbon monoxide - containing gas streams are passed over a catalyst to deposit a surface layer of active surface carbon thereon essentially without the formation of inactive coke. The active carbon is subsequently reacted with steam or hydrogen to form methane. Surprisingly, hydrogen and water vapor present in the feed gas do not adversely affect CO utilization significantly, and such hydrogen actually results in a significant increase in CO utilization.

Asset Management for Water and Wastewater Utilities

EPA Pesticide Factsheets

Renewing and replacing the nation's public water infrastructure is an ongoing task. Asset management can help a utility maximize the value of its capital as well as its operations and maintenance dollars.

Improving yield potential in crops under elevated CO2: Integrating the photosynthetic and nitrogen utilization efficiencies

PubMed Central

Kant, Surya; Seneweera, Saman; Rodin, Joakim; Materne, Michael; Burch, David; Rothstein, Steven J.; Spangenberg, German

2012-01-01

Increasing crop productivity to meet burgeoning human food demand is challenging under changing environmental conditions. Since industrial revolution atmospheric CO2 levels have linearly increased. Developing crop varieties with increased utilization of CO2 for photosynthesis is an urgent requirement to cope with the irreversible rise of atmospheric CO2 and achieve higher food production. The primary effects of elevated CO2 levels in most crop plants, particularly C3 plants, include increased biomass accumulation, although initial stimulation of net photosynthesis rate is only temporal and plants fail to sustain the maximal stimulation, a phenomenon known as photosynthesis acclimation. Despite this acclimation, grain yield is known to marginally increase under elevated CO2. The yield potential of C3 crops is limited by their capacity to exploit sufficient carbon. The “C fertilization” through elevated CO2 levels could potentially be used for substantial yield increase. Rubisco is the rate-limiting enzyme in photosynthesis and its activity is largely affected by atmospheric CO2 and nitrogen availability. In addition, maintenance of the C/N ratio is pivotal for various growth and development processes in plants governing yield and seed quality. For maximizing the benefits of elevated CO2, raising plant nitrogen pools will be necessary as part of maintaining an optimal C/N balance. In this review, we discuss potential causes for the stagnation in yield increases under elevated CO2 levels and explore possibilities to overcome this limitation by improved photosynthetic capacity and enhanced nitrogen use efficiency. Opportunities of engineering nitrogen uptake, assimilatory, and responsive genes are also discussed that could ensure optimal nitrogen allocation toward expanding source and sink tissues. This might avert photosynthetic acclimation partially or completely and drive for improved crop production under elevated CO2 levels. PMID:22833749

Improving yield potential in crops under elevated CO(2): Integrating the photosynthetic and nitrogen utilization efficiencies.

PubMed

Kant, Surya; Seneweera, Saman; Rodin, Joakim; Materne, Michael; Burch, David; Rothstein, Steven J; Spangenberg, German

2012-01-01

Increasing crop productivity to meet burgeoning human food demand is challenging under changing environmental conditions. Since industrial revolution atmospheric CO(2) levels have linearly increased. Developing crop varieties with increased utilization of CO(2) for photosynthesis is an urgent requirement to cope with the irreversible rise of atmospheric CO(2) and achieve higher food production. The primary effects of elevated CO(2) levels in most crop plants, particularly C(3) plants, include increased biomass accumulation, although initial stimulation of net photosynthesis rate is only temporal and plants fail to sustain the maximal stimulation, a phenomenon known as photosynthesis acclimation. Despite this acclimation, grain yield is known to marginally increase under elevated CO(2). The yield potential of C(3) crops is limited by their capacity to exploit sufficient carbon. The "C fertilization" through elevated CO(2) levels could potentially be used for substantial yield increase. Rubisco is the rate-limiting enzyme in photosynthesis and its activity is largely affected by atmospheric CO(2) and nitrogen availability. In addition, maintenance of the C/N ratio is pivotal for various growth and development processes in plants governing yield and seed quality. For maximizing the benefits of elevated CO(2), raising plant nitrogen pools will be necessary as part of maintaining an optimal C/N balance. In this review, we discuss potential causes for the stagnation in yield increases under elevated CO(2) levels and explore possibilities to overcome this limitation by improved photosynthetic capacity and enhanced nitrogen use efficiency. Opportunities of engineering nitrogen uptake, assimilatory, and responsive genes are also discussed that could ensure optimal nitrogen allocation toward expanding source and sink tissues. This might avert photosynthetic acclimation partially or completely and drive for improved crop production under elevated CO(2) levels.

Data Standardization for Carbon Cycle Modeling: Lessons Learned

NASA Astrophysics Data System (ADS)

Wei, Y.; Liu, S.; Cook, R. B.; Post, W. M.; Huntzinger, D. N.; Schwalm, C.; Schaefer, K. M.; Jacobson, A. R.; Michalak, A. M.

2012-12-01

Terrestrial biogeochemistry modeling is a crucial component of carbon cycle research and provides unique capabilities to understand terrestrial ecosystems. The Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) aims to identify key differences in model formulation that drive observed differences in model predictions of biospheric carbon exchange. To do so, the MsTMIP framework provides standardized prescribed environmental driver data and a standard model protocol to facilitate comparisons of modeling results from nearly 30 teams. Model performance is then evaluated against a variety of carbon-cycle related observations (remote sensing, atmospheric, and flux tower-based observations) using quantitative performance measures and metrics in an integrated evaluation framework. As part of this effort, we have harmonized highly diverse and heterogeneous environmental driver data, model outputs, and observational benchmark data sets to facilitate use and analysis by the MsTMIP team. In this presentation, we will describe the lessons learned from this data-intensive carbon cycle research. The data harmonization activity itself can be made more efficient with the consideration of proper tools, version control, workflow management, and collaboration within the whole team. The adoption of on-demand and interoperable protocols (e.g. OPeNDAP and Open Geospatial Consortium) makes data visualization and distribution more flexible. Users can customize and download data in specific spatial extent, temporal period, and different resolutions. The effort to properly organize data in an open and standard format (e.g. Climate & Forecast compatible netCDF) allows the data to be analysed by a dispersed set of researchers more efficiently, and maximizes the longevity and utilization of the data. The lessons learned from this specific experience can benefit efforts by the broader community to leverage diverse data resources more efficiently in scientific research.

Power Converters Maximize Outputs Of Solar Cell Strings

NASA Technical Reports Server (NTRS)

Frederick, Martin E.; Jermakian, Joel B.

1993-01-01

Microprocessor-controlled dc-to-dc power converters devised to maximize power transferred from solar photovoltaic strings to storage batteries and other electrical loads. Converters help in utilizing large solar photovoltaic arrays most effectively with respect to cost, size, and weight. Main points of invention are: single controller used to control and optimize any number of "dumb" tracker units and strings independently; power maximized out of converters; and controller in system is microprocessor.

The Naïve Utility Calculus: Computational Principles Underlying Commonsense Psychology.

PubMed

Jara-Ettinger, Julian; Gweon, Hyowon; Schulz, Laura E; Tenenbaum, Joshua B

2016-08-01

We propose that human social cognition is structured around a basic understanding of ourselves and others as intuitive utility maximizers: from a young age, humans implicitly assume that agents choose goals and actions to maximize the rewards they expect to obtain relative to the costs they expect to incur. This 'naïve utility calculus' allows both children and adults observe the behavior of others and infer their beliefs and desires, their longer-term knowledge and preferences, and even their character: who is knowledgeable or competent, who is praiseworthy or blameworthy, who is friendly, indifferent, or an enemy. We review studies providing support for the naïve utility calculus, and we show how it captures much of the rich social reasoning humans engage in from infancy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Carbonic anhydrase from Camelia sinensis (tea) leaves.

PubMed

Demir, Y; Demir, N; Ağar, G

1997-11-01

Carbonic anhydrase (CA) (carbonate hydrolyase; E,C,4.2.1.1) from leaves of mature Camelia sinensis was purified and characterized. The purification level was 53 fold. The optimum temperature for maximal enzyme activity is 50 degrees C. The optimum pH was 6.8 and this pH varied between 6.5 and 7.5. Each enzyme molecule is a hexamer with an M(r) of 169,000 with subunits of M(r) = 28,000.

Reading the Tea Leaves: How Utilities in the West Are Managing Carbon Regulatory Risk in their Resource Plans

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

Barbose, Galen; Wiser, Ryan; Phadke, Amol

2008-02-01

The long economic lifetime and development lead-time of many electric infrastructure investments requires that utility resource planning consider potential costs and risks over a lengthy time horizon. One long-term -- and potentially far-reaching -- risk currently facing the electricity industry is the uncertain cost of future carbon dioxide (CO2) regulations. Recognizing the importance of this issue, many utilities (sometimes spurred by state regulatory requirements) are beginning to actively assess carbon regulatory risk within their resource planning processes, and to evaluate options for mitigating that risk. However, given the relatively recent emergence of this issue and the rapidly changing political landscape,more » methods and assumptions used to analyze carbon regulatory risk, and the impact of this analysis on the selection of a preferred resource portfolio, vary considerably across utilities. In this study, we examine the treatment of carbon regulatory risk in utility resource planning, through a comparison of the most-recent resource plans filed by fifteen investor-owned and publicly-owned utilities in the Western U.S. Together, these utilities account for approximately 60percent of retail electricity sales in the West, and cover nine of eleven Western states. This report has two related elements. First, we compare and assess utilities' approaches to addressing key analytical issues that arise when considering the risk of future carbon regulations. Second, we summarize the composition and carbon intensity of the preferred resource portfolios selected by these fifteen utilities and compare them to potential CO2 emission benchmark levels.« less

Simulation study to determine the feasibility of injecting hydrogen sulfide, carbon dioxide and nitrogen gas injection to improve gas and oil recovery oil-rim reservoir

NASA Astrophysics Data System (ADS)

Eid, Mohamed El Gohary

This study is combining two important and complicated processes; Enhanced Oil Recovery, EOR, from the oil rim and Enhanced Gas Recovery, EGR from the gas cap using nonhydrocarbon injection gases. EOR is proven technology that is continuously evolving to meet increased demand and oil production and desire to augment oil reserves. On the other hand, the rapid growth of the industrial and urban development has generated an unprecedented power demand, particularly during summer months. The required gas supplies to meet this demand are being stretched. To free up gas supply, alternative injectants to hydrocarbon gas are being reviewed to support reservoir pressure and maximize oil and gas recovery in oil rim reservoirs. In this study, a multi layered heterogeneous gas reservoir with an oil rim was selected to identify the most optimized development plan for maximum oil and gas recovery. The integrated reservoir characterization model and the pertinent transformed reservoir simulation history matched model were quality assured and quality checked. The development scheme is identified, in which the pattern and completion of the wells are optimized to best adapt to the heterogeneity of the reservoir. Lateral and maximum block contact holes will be investigated. The non-hydrocarbon gases considered for this study are hydrogen sulphide, carbon dioxide and nitrogen, utilized to investigate miscible and immiscible EOR processes. In November 2010, re-vaporization study, was completed successfully, the first in the UAE, with an ultimate objective is to examine the gas and condensate production in gas reservoir using non hydrocarbon gases. Field development options and proces schemes as well as reservoir management and long term business plans including phases of implementation will be identified and assured. The development option that maximizes the ultimate recovery factor will be evaluated and selected. The study achieved satisfactory results in integrating gas and oil reservoir management methodology to maximize both fluid recovery and free up currently injected HC gases for domestic consumption. Moreover, this study identified the main uncertainty parameters impacting the gas and oil production performance with all proposed alternatives. Maximizing both fluids oil and gas in oil rim reservoir are challenging. The reservoir heterogeneity will have a major impact on the performance of non hydrocarbon gas flooding. Therefore, good reservoir description is a key to achieve acceptable development process and make reliable prediction. The lab study data were used successfully to as a tool to identify the range of uncertainty parameters that are impacting the hydrocarbon recovery.

How to access and exploit natural resources sustainably: petroleum biotechnology.

PubMed

Sherry, Angela; Andrade, Luiza; Velenturf, Anne; Christgen, Beate; Gray, Neil D; Head, Ian M

2017-09-01

As we transition from fossil fuel reliance to a new energy future, innovative microbial biotechnologies may offer new routes to maximize recovery from conventional and unconventional energy assets; as well as contributing to reduced emission pathways and new technologies for carbon capture and utilization. Here we discuss the role of microbiology in petroleum biotechnologies in relation to addressing UN Sustainable Development Goal 12 (ensure sustainable consumption and production patterns), with a focus on microbially-mediated energy recovery from unconventionals (heavy oil to methane), shale gas and fracking, bioelectrochemical systems for the production of electricity from fossil fuel resources, and innovations in synthetic biology. Furthermore, using wastes to support a more sustainable approach to fossil fuel extraction processes is considered as we undertake the move towards a more circular global economy. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Cognitive Somatic Behavioral Interventions for Maximizing Gymnastic Performance.

ERIC Educational Resources Information Center

Ravizza, Kenneth; Rotella, Robert

Psychological training programs developed and implemented for gymnasts of a wide range of age and varying ability levels are examined. The programs utilized strategies based on cognitive-behavioral intervention. The approach contends that mental training plays a crucial role in maximizing performance for most gymnasts. The object of the training…

Economics of Red Pine Management for Utility Pole Timber

Treesearch

Gerald H. Grossman; Karen Potter-Witter

1991-01-01

Including utility poles in red pine management regimes leads to distinctly different management recommendations. Where utility pole markets exist, managing for poles will maximize net returns. To do so, plantations should be maintained above 110 ft2/ac, higher than usually recommended. In Michigan's northern lower peninsula, approximately...

Electroconductive PET/SWNT Films by Solution Casting

NASA Technical Reports Server (NTRS)

Steinert, Brian W.; Dean, Derrick R.

2008-01-01

The market for electrically conductive polymers is rapidly growing, and an emerging pathway for attaining these materials is via polymer-carbon nanotube (CNT) nanocomposites, because of the superior properties of CNTs. Due to their excellent electrical properties and anisotropic magnetic susceptibility, we expect CNTs could be easily aligned to maximize their effectiveness in imparting electrical conductivity to the polymer matrix. Single-walled carbon nanotubes (SWNT) were dispersed in a polyethylene terephthalate (PET) matrix by solution blending then cast onto a glass substrate to create thin, flexible films. Various SWNT loading concentrations were implemented (0.5, 1.0, and 3.0 wt.%) to study the effect of additive density. The processing method was repeated to produce films in the presence of magnetic fields (3 and 9.4 Tesla). The SWNTs showed a high susceptibility to the magnetic field and were effectively aligned in the PET matrix. The alignment was characterized with Raman spectroscopy. Impedance spectroscopy was utilized to study the electrical behavior of the films. Concentration and dispersion seemed to play very important roles in improving electrical conductivity, while alignment played a secondary and less significant role. The most interesting result proved to be the effect of a magnetic field during processing. It appears that a magnetic field may improve dispersion of unmodified SWNTs, which seems to be more important than alignment. It was concluded that SWNTs offer a good option as conductive, nucleating filler for electroconductive polymer applications, and the utilization of a magnetic field may prove to be a novel method for CNT dispersion that could lead to improved nanocomposite materials.

Age-related patterns of forest complexity and carbon storage in pine and aspen-birch ecosystems of northern Minnesota, USA

Treesearch

John B. Bradford; Douglas N. Kastendick

2010-01-01

Forest managers are seeking strategies to create stands that can adapt to new climatic conditions and simultaneously help mitigate increases in atmospheric CO2. Adaptation strategies often focus on enhancing resilience by maximizing forest complexity in terms of species composition and size structure, while mitigation involves sustaining carbon...

Computers and the Environment: Minimizing the Carbon Footprint

ERIC Educational Resources Information Center

Kaestner, Rich

2009-01-01

Computers can be good and bad for the environment; one can maximize the good and minimize the bad. When dealing with environmental issues, it's difficult to ignore the computing infrastructure. With an operations carbon footprint equal to the airline industry's, computer energy use is only part of the problem; everyone is also dealing with the use…

Expected Power-Utility Maximization Under Incomplete Information and with Cox-Process Observations

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

Fujimoto, Kazufumi, E-mail: m_fuji@kvj.biglobe.ne.jp; Nagai, Hideo, E-mail: nagai@sigmath.es.osaka-u.ac.jp; Runggaldier, Wolfgang J., E-mail: runggal@math.unipd.it

2013-02-15

We consider the problem of maximization of expected terminal power utility (risk sensitive criterion). The underlying market model is a regime-switching diffusion model where the regime is determined by an unobservable factor process forming a finite state Markov process. The main novelty is due to the fact that prices are observed and the portfolio is rebalanced only at random times corresponding to a Cox process where the intensity is driven by the unobserved Markovian factor process as well. This leads to a more realistic modeling for many practical situations, like in markets with liquidity restrictions; on the other hand itmore » considerably complicates the problem to the point that traditional methodologies cannot be directly applied. The approach presented here is specific to the power-utility. For log-utilities a different approach is presented in Fujimoto et al. (Preprint, 2012).« less

Partitioning-based mechanisms under personalized differential privacy.

PubMed

Li, Haoran; Xiong, Li; Ji, Zhanglong; Jiang, Xiaoqian

2017-05-01

Differential privacy has recently emerged in private statistical aggregate analysis as one of the strongest privacy guarantees. A limitation of the model is that it provides the same privacy protection for all individuals in the database. However, it is common that data owners may have different privacy preferences for their data. Consequently, a global differential privacy parameter may provide excessive privacy protection for some users, while insufficient for others. In this paper, we propose two partitioning-based mechanisms, privacy-aware and utility-based partitioning, to handle personalized differential privacy parameters for each individual in a dataset while maximizing utility of the differentially private computation. The privacy-aware partitioning is to minimize the privacy budget waste, while utility-based partitioning is to maximize the utility for a given aggregate analysis. We also develop a t -round partitioning to take full advantage of remaining privacy budgets. Extensive experiments using real datasets show the effectiveness of our partitioning mechanisms.

Partitioning-based mechanisms under personalized differential privacy

PubMed Central

Li, Haoran; Xiong, Li; Ji, Zhanglong; Jiang, Xiaoqian

2017-01-01

Differential privacy has recently emerged in private statistical aggregate analysis as one of the strongest privacy guarantees. A limitation of the model is that it provides the same privacy protection for all individuals in the database. However, it is common that data owners may have different privacy preferences for their data. Consequently, a global differential privacy parameter may provide excessive privacy protection for some users, while insufficient for others. In this paper, we propose two partitioning-based mechanisms, privacy-aware and utility-based partitioning, to handle personalized differential privacy parameters for each individual in a dataset while maximizing utility of the differentially private computation. The privacy-aware partitioning is to minimize the privacy budget waste, while utility-based partitioning is to maximize the utility for a given aggregate analysis. We also develop a t-round partitioning to take full advantage of remaining privacy budgets. Extensive experiments using real datasets show the effectiveness of our partitioning mechanisms. PMID:28932827

Utilization of Cheese Whey Using Synergistic Immobilization of β-Galactosidase and Saccharomyces cerevisiae Cells in Dual Matrices.

PubMed

Kokkiligadda, Anusha; Beniwal, Arun; Saini, Priyanka; Vij, Shilpa

2016-08-01

Whey is a byproduct of the dairy industry, which has prospects of using as a source for production of various valuable compounds. The lactose present in whey is considered as an environmental pollutant and its utilization for enzyme and fuel production, may be effective for whey bioremediation. The dairy yeast Kluyveromyces marxianus have the ability to utilize lactose sharply as the major carbon source for the production of the enzyme. Five strains were tested for the production of the β-galactosidase using whey. The maximum β-galactosidase activity of 1.74 IU/mg dry weight was achieved in whey using K. marxianus MTCC 1389. The biocatalyst was further immobilized on chitosan macroparticles and exhibited excellent functional activity at 35 °C. Almost 89 % lactose hydrolysis was attained for concentrated whey (100 g/L) and retained 89 % catalytic activity after 15 cycles of reuse. Finally, β-galactosidase was immobilized on chitosan and Saccharomyces cerevisiae on calcium alginate, and both were used together for the production of ethanol from concentrated whey. Maximal ethanol titer of 28.9 g/L was achieved during fermentation at 35 °C. The conclusions generated by employing two different matrices will be beneficial for the future modeling using engineered S. cerevisiae in scale-up studies.

Climate change and long-term fire management impacts on Australian savannas.

PubMed

Scheiter, Simon; Higgins, Steven I; Beringer, Jason; Hutley, Lindsay B

2015-02-01

Tropical savannas cover a large proportion of the Earth's land surface and many people are dependent on the ecosystem services that savannas supply. Their sustainable management is crucial. Owing to the complexity of savanna vegetation dynamics, climate change and land use impacts on savannas are highly uncertain. We used a dynamic vegetation model, the adaptive dynamic global vegetation model (aDGVM), to project how climate change and fire management might influence future vegetation in northern Australian savannas. Under future climate conditions, vegetation can store more carbon than under ambient conditions. Changes in rainfall seasonality influence future carbon storage but do not turn vegetation into a carbon source, suggesting that CO₂ fertilization is the main driver of vegetation change. The application of prescribed fires with varying return intervals and burning season influences vegetation and fire impacts. Carbon sequestration is maximized with early dry season fires and long fire return intervals, while grass productivity is maximized with late dry season fires and intermediate fire return intervals. The study has implications for management policy across Australian savannas because it identifies how fire management strategies may influence grazing yield, carbon sequestration and greenhouse gas emissions. This knowledge is crucial to maintaining important ecosystem services of Australian savannas. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Using Classification Trees to Predict Alumni Giving for Higher Education

ERIC Educational Resources Information Center

Weerts, David J.; Ronca, Justin M.

2009-01-01

As the relative level of public support for higher education declines, colleges and universities aim to maximize alumni-giving to keep their programs competitive. Anchored in a utility maximization framework, this study employs the classification and regression tree methodology to examine characteristics of alumni donors and non-donors at a…

The Self in Decision Making and Decision Implementation.

ERIC Educational Resources Information Center

Beach, Lee Roy; Mitchell, Terence R.

Since the early 1950's the principal prescriptive model in the psychological study of decision making has been maximization of Subjective Expected Utility (SEU). This SEU maximization has come to be regarded as a description of how people go about making decisions. However, while observed decision processes sometimes resemble the SEU model,…

Designing Agent Collectives For Systems With Markovian Dynamics

NASA Technical Reports Server (NTRS)

Wolpert, David H.; Lawson, John W.; Clancy, Daniel (Technical Monitor)

2001-01-01

The "Collective Intelligence" (COIN) framework concerns the design of collectives of agents so that as those agents strive to maximize their individual utility functions, their interaction causes a provided "world" utility function concerning the entire collective to be also maximized. Here we show how to extend that framework to scenarios having Markovian dynamics when no re-evolution of the system from counter-factual initial conditions (an often expensive calculation) is permitted. Our approach transforms the (time-extended) argument of each agent's utility function before evaluating that function. This transformation has benefits in scenarios not involving Markovian dynamics, in particular scenarios where not all of the arguments of an agent's utility function are observable. We investigate this transformation in simulations involving both linear and quadratic (nonlinear) dynamics. In addition, we find that a certain subset of these transformations, which result in utilities that have low "opacity (analogous to having high signal to noise) but are not "factored" (analogous to not being incentive compatible), reliably improve performance over that arising with factored utilities. We also present a Taylor Series method for the fully general nonlinear case.

Carbon source-sink limitations differ between two species with contrasting growth strategies: Source-sink limitations vary with growth strategy

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

Burnett, Angela C.; Rogers, A.; Rees, M.

When we understand how carbon source and sink strengths limit plant growth we realized how critical the knowledge gap is in hindering efforts to maximize crop yield. Here, we investigated how differences in growth rate arise from source–sink limitations, using a model system comparing a fast-growing domesticated annual barley (Hordeum vulgare cv. NFC Tipple) with a slow-growing wild perennial relative (Hordeum bulbosum). Source strength was manipulated by growing plants at sub-ambient and elevated CO 2 concentrations ([CO 2]). Limitations on vegetative growth imposed by source and sink were diagnosed by measuring relative growth rate, developmental plasticity, photosynthesis and major carbonmore » and nitrogen metabolite pools. Growth was sink limited in the annual but source limited in the perennial. RGR and carbon acquisition were higher in the annual, but photosynthesis responded weakly to elevated [CO 2] indicating that source strength was near maximal at current [CO 2]. In contrast, photosynthetic rate and sink development responded strongly to elevated [CO 2] in the perennial, indicating significant source limitation. Sink limitation was avoided in the perennial by high sink plasticity: a marked increase in tillering and root:shoot ratio at elevated [CO 2], and lower non-structural carbohydrate accumulation. Finally, by alleviating sink limitation during vegetative development could be important for maximizing growth of elite cereals under future elevated [CO 2].« less

Biofuel cells based on direct enzyme-electrode contacts using PQQ-dependent glucose dehydrogenase/bilirubin oxidase and modified carbon nanotube materials.

PubMed

Scherbahn, V; Putze, M T; Dietzel, B; Heinlein, T; Schneider, J J; Lisdat, F

2014-11-15

Two types of carbon nanotube electrodes (1) buckypaper (BP) and (2) vertically aligned carbon nanotubes (vaCNT) have been used for elaboration of glucose/O2 enzymatic fuel cells exploiting direct electron transfer. For the anode pyrroloquinoline quinone dependent glucose dehydrogenase ((PQQ)GDH) has been immobilized on [poly(3-aminobenzoic acid-co-2-methoxyaniline-5-sulfonic acid), PABMSA]-modified electrodes. For the cathode bilirubin oxidase (BOD) has been immobilized on PQQ-modified electrodes. PABMSA and PQQ act as promoter for enzyme bioelectrocatalysis. The voltammetric characterization of each electrode shows current densities in the range of 0.7-1.3 mA/cm(2). The BP-based fuel cell exhibits maximal power density of about 107 µW/cm(2) (at 490 mV). The vaCNT-based fuel cell achieves a maximal power density of 122 µW/cm(2) (at 540 mV). Even after three days and several runs of load a power density over 110 µW/cm(2) is retained with the second system (10mM glucose). Due to a better power exhibition and an enhanced stability of the vaCNT-based fuel cells they have been studied in human serum samples and a maximal power density of 41 µW/cm(2) (390 mV) can be achieved. Copyright © 2014 Elsevier B.V. All rights reserved.

Carbon source-sink limitations differ between two species with contrasting growth strategies: Source-sink limitations vary with growth strategy

DOE PAGES

Burnett, Angela C.; Rogers, A.; Rees, M.; ...

2016-09-22

When we understand how carbon source and sink strengths limit plant growth we realized how critical the knowledge gap is in hindering efforts to maximize crop yield. Here, we investigated how differences in growth rate arise from source–sink limitations, using a model system comparing a fast-growing domesticated annual barley (Hordeum vulgare cv. NFC Tipple) with a slow-growing wild perennial relative (Hordeum bulbosum). Source strength was manipulated by growing plants at sub-ambient and elevated CO 2 concentrations ([CO 2]). Limitations on vegetative growth imposed by source and sink were diagnosed by measuring relative growth rate, developmental plasticity, photosynthesis and major carbonmore » and nitrogen metabolite pools. Growth was sink limited in the annual but source limited in the perennial. RGR and carbon acquisition were higher in the annual, but photosynthesis responded weakly to elevated [CO 2] indicating that source strength was near maximal at current [CO 2]. In contrast, photosynthetic rate and sink development responded strongly to elevated [CO 2] in the perennial, indicating significant source limitation. Sink limitation was avoided in the perennial by high sink plasticity: a marked increase in tillering and root:shoot ratio at elevated [CO 2], and lower non-structural carbohydrate accumulation. Finally, by alleviating sink limitation during vegetative development could be important for maximizing growth of elite cereals under future elevated [CO 2].« less

Carbon emissions associated with the procurement and utilization of forest harvest residues for energy, northern Minnesota, USA

Treesearch

Grant M. Domke; Dennis R. Becker; Anthony W. D' Amato; Alan R. Ek; Christopher W. Woodall

2012-01-01

Interest in the use of forest-derived biomass for energy has prompted comparisons to fossil fuels and led to controversy over the atmospheric consequences of its utilization. Much of the debate has centered on the carbon storage implications of utilizing whole trees for energy and the time frame necessary to offset the carbon emissions associated with fixed-life...

An optimization model for carbon capture & storage/utilization vs. carbon trading: A case study of fossil-fired power plants in Turkey.

PubMed

Ağralı, Semra; Üçtuğ, Fehmi Görkem; Türkmen, Burçin Atılgan

2018-06-01

We consider fossil-fired power plants that operate in an environment where a cap and trade system is in operation. These plants need to choose between carbon capture and storage (CCS), carbon capture and utilization (CCU), or carbon trading in order to obey emissions limits enforced by the government. We develop a mixed-integer programming model that decides on the capacities of carbon capture units, if it is optimal to install them, the transportation network that needs to be built for transporting the carbon captured, and the locations of storage sites, if they are decided to be built. Main restrictions on the system are the minimum and maximum capacities of the different parts of the pipeline network, the amount of carbon that can be sold to companies for utilization, and the capacities on the storage sites. Under these restrictions, the model aims to minimize the net present value of the sum of the costs associated with installation and operation of the carbon capture unit and the transportation of carbon, the storage cost in case of CCS, the cost (or revenue) that results from the emissions trading system, and finally the negative revenue of selling the carbon to other entities for utilization. We implement the model on General Algebraic Modeling System (GAMS) by using data associated with two coal-fired power plants located in different regions of Turkey. We choose enhanced oil recovery (EOR) as the process in which carbon would be utilized. The results show that CCU is preferable to CCS as long as there is sufficient demand in the EOR market. The distance between the location of emission and location of utilization/storage, and the capacity limits on the pipes are an important factor in deciding between carbon capture and carbon trading. At carbon prices over $15/ton, carbon capture becomes preferable to carbon trading. These results show that as far as Turkey is concerned, CCU should be prioritized as a means of reducing nation-wide carbon emissions in an environmentally and economically rewarding manner. The model developed in this study is generic, and it can be applied to any industry at any location, as long as the required inputs are available. Copyright © 2018 Elsevier Ltd. All rights reserved.

Climate Change Mitigation Challenge for Wood Utilization-The Case of Finland.

PubMed

Soimakallio, Sampo; Saikku, Laura; Valsta, Lauri; Pingoud, Kim

2016-05-17

The urgent need to mitigate climate change invokes both opportunities and challenges for forest biomass utilization. Fossil fuels can be substituted by using wood products in place of alternative materials and energy, but wood harvesting reduces forest carbon sink and processing of wood products requires material and energy inputs. We assessed the extended life cycle carbon emissions considering substitution impacts for various wood utilization scenarios over 100 years from 2010 onward for Finland. The scenarios were based on various but constant wood utilization structures reflecting current and anticipated mix of wood utilization activities. We applied stochastic simulation to deal with the uncertainty in a number of input variables required. According to our analysis, the wood utilization decrease net carbon emissions with a probability lower than 40% for each of the studied scenarios. Furthermore, large emission reductions were exceptionally unlikely. The uncertainty of the results were influenced clearly the most by the reduction in the forest carbon sink. There is a significant trade-off between avoiding emissions through fossil fuel substitution and reduction in forest carbon sink due to wood harvesting. This creates a major challenge for forest management practices and wood utilization activities in responding to ambitious climate change mitigation targets.

PEM-PCA: a parallel expectation-maximization PCA face recognition architecture.

PubMed

Rujirakul, Kanokmon; So-In, Chakchai; Arnonkijpanich, Banchar

2014-01-01

Principal component analysis or PCA has been traditionally used as one of the feature extraction techniques in face recognition systems yielding high accuracy when requiring a small number of features. However, the covariance matrix and eigenvalue decomposition stages cause high computational complexity, especially for a large database. Thus, this research presents an alternative approach utilizing an Expectation-Maximization algorithm to reduce the determinant matrix manipulation resulting in the reduction of the stages' complexity. To improve the computational time, a novel parallel architecture was employed to utilize the benefits of parallelization of matrix computation during feature extraction and classification stages including parallel preprocessing, and their combinations, so-called a Parallel Expectation-Maximization PCA architecture. Comparing to a traditional PCA and its derivatives, the results indicate lower complexity with an insignificant difference in recognition precision leading to high speed face recognition systems, that is, the speed-up over nine and three times over PCA and Parallel PCA.

Carbon storage in managed forests of the northern Great Lake States

Treesearch

Jeanette L. Rollinger; Terry F. Strong

1996-01-01

Carbon (C) storage in forest ecosystems is a significant part of the total terrestrial C pool, and may potentially be manipulated as an important C sink. The influence of management on C pools must be understood before guidelines can be suggested for maximizing C sequestration in forests. Studies of hardwood, red pine (Pinus resinosa Ait.), aspen and...

Design Constraints on a Synthetic Metabolism

PubMed Central

Bilgin, Tugce; Wagner, Andreas

2012-01-01

A metabolism is a complex network of chemical reactions that converts sources of energy and chemical elements into biomass and other molecules. To design a metabolism from scratch and to implement it in a synthetic genome is almost within technological reach. Ideally, a synthetic metabolism should be able to synthesize a desired spectrum of molecules at a high rate, from multiple different nutrients, while using few chemical reactions, and producing little or no waste. Not all of these properties are achievable simultaneously. We here use a recently developed technique to create random metabolic networks with pre-specified properties to quantify trade-offs between these and other properties. We find that for every additional molecule to be synthesized a network needs on average three additional reactions. For every additional carbon source to be utilized, it needs on average two additional reactions. Networks able to synthesize 20 biomass molecules from each of 20 alternative sole carbon sources need to have at least 260 reactions. This number increases to 518 reactions for networks that can synthesize more than 60 molecules from each of 80 carbon sources. The maximally achievable rate of biosynthesis decreases by approximately 5 percent for every additional molecule to be synthesized. Biochemically related molecules can be synthesized at higher rates, because their synthesis produces less waste. Overall, the variables we study can explain 87 percent of variation in network size and 84 percent of the variation in synthesis rate. The constraints we identify prescribe broad boundary conditions that can help to guide synthetic metabolism design. PMID:22768162

Carbon allocation to major metabolites in illuminated leaves is not just proportional to photosynthesis when gaseous conditions (CO2 and O2 ) vary.

PubMed

Abadie, Cyril; Bathellier, Camille; Tcherkez, Guillaume

2018-04-01

In gas-exchange experiments, manipulating CO 2 and O 2 is commonly used to change the balance between carboxylation and oxygenation. Downstream metabolism (utilization of photosynthetic and photorespiratory products) may also be affected by gaseous conditions but this is not well documented. Here, we took advantage of sunflower as a model species, which accumulates chlorogenate in addition to sugars and amino acids (glutamate, alanine, glycine and serine). We performed isotopic labelling with 13 CO 2 under different CO 2 /O 2 conditions, and determined 13 C contents to compute 13 C-allocation patterns and build-up rates. The 13 C content in major metabolites was not found to be a constant proportion of net fixed carbon but, rather, changed dramatically with CO 2 and O 2 . Alanine typically accumulated at low O 2 (hypoxic response) while photorespiratory intermediates accumulated under ambient conditions and at high photorespiration, glycerate accumulation exceeding serine and glycine build-up. Chlorogenate synthesis was relatively more important under normal conditions and at high CO 2 and its synthesis was driven by phosphoenolpyruvate de novo synthesis. These findings demonstrate that carbon allocation to metabolites other than photosynthetic end products is affected by gaseous conditions and therefore the photosynthetic yield of net nitrogen assimilation varies, being minimal at high CO 2 and maximal at high O 2 . © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Ectoines as compatible solutes and carbon and energy sources for the halophilic bacterium Chromohalobacter salexigens.

PubMed

Vargas, C; Jebbar, M; Carrasco, R; Blanco, C; Calderón, M I; Iglesias-Guerra, F; Nieto, J J

2006-01-01

To investigate the catabolism of ectoine and hydroxyectoine, which are the major compatible solutes synthesized by Chromohalobacter salexigens. Growth curves performed in M63 minimal medium with low (0.75 mol l(-1) NaCl), optimal (1.5 mol l(-1) NaCl) or high (2.5 mol l(-1) NaCl) salinity revealed that betaine and ectoines were used as substrate for growth at optimal and high salt. Ectoine transport was maximal at optimal salinity, and showed 3- and 1.5-fold lower values at low and high salinity respectively. The salt-sensitive ectA mutant CHR62 showed an ectoine transport rate 6.8-fold higher than that of the wild type. Incubation of C. salexigens in a mixture of glucose and ectoine resulted in a biphasic growth pattern. However, CO(2) production due to ectoine catabolism was lower, but not completely abolished, in the presence of glucose. When used as the sole carbon source, glycine betaine effectively inhibited ectoine and hydroxyectoine synthesis at any salinity. The catabolic pathways for ectoine and hydroxyectoine in C. salexigens operate at optimal and high (although less efficiently) salinity. Endogenous ectoine(s) may repress its own transport. Ectoine utilization was only partially repressed by glucose. Betaine, when used as carbon source, suppresses synthesis of ectoines even under high osmolarity conditions. This study is a previous step to the subsequent isolation and manipulation of the catabolic genes, so as to generate strains with enhanced production of ectoine and hydroxyectoine.

A Constrained Maximization Model for inspecting the impact of leaf shape on optimal leaf size and stoma resistance

NASA Astrophysics Data System (ADS)

Ding, J.; Johnson, E. A.; Martin, Y. E.

2017-12-01

Leaf is the basic production unit of plants. Water is the most critical resource of plants. Its availability controls primary productivity of plants by affecting leaf carbon budget. To avoid the damage of cavitation from lowering vein water potential t caused by evapotranspiration, the leaf must increase the stomatal resistance to reduce evapotranspiration rate. This comes at the cost of reduced carbon fixing rate as increasing stoma resistance meanwhile slows carbon intake rate. Studies suggest that stoma will operate at an optimal resistance to maximize the carbon gain with respect to water. Different plant species have different leaf shapes, a genetically determined trait. Further, on the same plant leaf size can vary many times in size that is related to soil moisture, an indicator of water availability. According to metabolic scaling theory, increasing leaf size will increase total xylem resistance of vein, which may also constrain leaf carbon budget. We present a Constrained Maximization Model of leaf (leaf CMM) that incorporates metabolic theory into the coupling of evapotranspiration and carbon fixation to examine how leaf size, stoma resistance and maximum net leaf primary productivity change with petiole xylem water potential. The model connects vein network structure to leaf shape and use the difference between petiole xylem water potential and the critical minor vein cavitation forming water potential as the budget. The CMM shows that both maximum net leaf primary production and optimal leaf size increase with petiole xylem water potential while optimal stoma resistance decreases. Narrow leaf has overall lower optimal leaf size and maximum net leaf carbon gain and higher optimal stoma resistance than those of broad leaf. This is because with small width to length ratio, total xylem resistance increases faster with leaf size. Total xylem resistance of narrow leaf increases faster with leaf size causing higher average and marginal cost of xylem water potential with respect to net leaf carbon gain. With same leaf area, total xylem resistance of narrow leaf is higher than broad leaf. Given same stoma resistance and petiole water potential, narrow leaf will lose more xylem water potential than broad leaf. Consequently, narrow leaf has smaller size and higher stoma resistance at optimum.

Analysis of Carbon Policies for Electricity Networks with High Penetration of Green Generation

NASA Astrophysics Data System (ADS)

Feijoo, Felipe A.

In recent decades, climate change has become one of the most crucial challenges for humanity. Climate change has a direct correlation with global warming, caused mainly by the green house gas emissions (GHG). The Environmental Protection Agency in the U.S. (EPA) attributes carbon dioxide to account for approximately 82% of the GHG emissions. Unfortunately, the energy sector is the main producer of carbon dioxide, with China and the U.S. as the highest emitters. Therefore, there is a strong (positive) correlation between energy production, global warming, and climate change. Stringent carbon emissions reduction targets have been established in order to reduce the impacts of GHG. Achieving these emissions reduction goals will require implementation of policies like as cap-and-trade and carbon taxes, together with transformation of the electricity grid into a smarter system with high green energy penetration. However, the consideration of policies solely in view of carbon emissions reduction may adversely impact other market outcomes such as electricity prices and consumption. In this dissertation, a two-layer mathematical-statistical framework is presented, that serves to develop carbon policies to reduce emissions level while minimizing the negative impacts on other market outcomes. The bottom layer of the two layer model comprises a bi-level optimization problem. The top layer comprises a statistical model and a Pareto analysis. Two related but different problems are studied under this methodology. The first problem looks into the design of cap-and-trade policies for deregulated electricity markets that satisfy the interest of different market constituents. Via the second problem, it is demonstrated how the framework can be used to obtain levels of carbon emissions reduction while minimizing the negative impact on electricity demand and maximizing green penetration from microgrids. In the aforementioned studies, forecasts for electricity prices and production cost are considered. This, this dissertation also presents anew forecast model that can be easily integrated in the two-layer framework. It is demonstrated in this dissertation that the proposed framework can be utilized by policy-makers, power companies, consumers, and market regulators in developing emissions policy decisions, bidding strategies, market regulations, and electricity dispatch strategies.

Social and Professional Participation of Individuals Who Are Deaf: Utilizing the Psychosocial Potential Maximization Framework

ERIC Educational Resources Information Center

Jacobs, Paul G.; Brown, P. Margaret; Paatsch, Louise

2012-01-01

This article documents a strength-based understanding of how individuals who are deaf maximize their social and professional potential. This exploratory study was conducted with 49 adult participants who are deaf (n = 30) and who have typical hearing (n = 19) residing in America, Australia, England, and South Africa. The findings support a…

Using Debate to Maximize Learning Potential: A Case Study

ERIC Educational Resources Information Center

Firmin, Michael W.; Vaughn, Aaron; Dye, Amanda

2007-01-01

Following a review of the literature, an educational case study is provided for the benefit of faculty preparing college courses. In particular, we provide a transcribed debate utilized in a General Psychology course as a best practice example of how to craft a debate which maximizes student learning. The work is presented as a model for the…

Effect of maximal dynamic exercise on exhaled ethane and carbon monoxide levels in human, equine, and canine athletes.

PubMed

Wyse, Cathy; Cathcart, Andy; Sutherland, Rona; Ward, Susan; McMillan, Lesley; Gibson, Graham; Padgett, Miles; Skeldon, Kenneth

2005-06-01

Exercise-induced oxidative stress (EIOS) refers to a condition where the balance of free radical production and antioxidant systems is disturbed during exercise in favour of pro-oxidant free radicals. Breath ethane is a product of free radical-mediated oxidation of cell membrane lipids and is considered to be a reliable marker of oxidative stress. The heatshock protein, haem oxygenase, is induced by oxidative stress and degrades haemoglobin to bilirubin, with concurrent production of carbon monoxide (CO). The aim of this study was to investigate the effect of maximal exercise on exhaled ethane and CO in human, canine, and equine athletes. Human athletes (n = 8) performed a maximal exercise test on a treadmill, and canine (n = 12) and equine (n = 11) athletes exercised at gallop on a sand racetrack. Breath samples were taken at regular intervals during exercise in the human athletes, and immediately before and after exercise in the canine and equine athletes. Breath samples were stored in gas-impermeable bags for analysis of ethane by laser spectroscopy, and CO was measured directly using an electrochemical CO monitor. Maximal exercise was associated with significant increases in exhaled ethane in the human, equine, and canine athletes. Decreased concentrations of exhaled CO were detected after maximal exercise in the human athletes, but CO was rarely detectable in the canine and equine athletes. The ethane breath test allows non-invasive and real-time detection of oxidative stress, and this method will facilitate further investigation of the processes mediating EIOS in human and animal athletes.

Can differences in breast cancer utilities explain disparities in breast cancer care?

PubMed

Schleinitz, Mark D; DePalo, Dina; Blume, Jeffrey; Stein, Michael

2006-12-01

Black, older, and less affluent women are less likely to receive adjuvant breast cancer therapy than their counterparts. Whereas preference contributes to disparities in other health care scenarios, it is unclear if preference explains differential rates of breast cancer care. To ascertain utilities from women of diverse backgrounds for the different stages of, and treatments for, breast cancer and to determine whether a treatment decision modeled from utilities is associated with socio-demographic characteristics. A stratified sample (by age and race) of 156 English-speaking women over 25 years old not currently undergoing breast cancer treatment. We assessed utilities using standard gamble for 5 breast cancer stages, and time-tradeoff for 3 therapeutic modalities. We incorporated each subject's utilities into a Markov model to determine whether her quality-adjusted life expectancy would be maximized with chemotherapy for a hypothetical, current diagnosis of stage II breast cancer. We used logistic regression to determine whether socio-demographic variables were associated with this optimal strategy. Median utilities for the 8 health states were: stage I disease, 0.91 (interquartile range 0.50 to 1.00); stage II, 0.75 (0.26 to 0.99); stage III, 0.51 (0.25 to 0.94); stage IV (estrogen receptor positive), 0.36 (0 to 0.75); stage IV (estrogen receptor negative), 0.40 (0 to 0.79); chemotherapy 0.50 (0 to 0.92); hormonal therapy 0.58 (0 to 1); and radiation therapy 0.83 (0.10 to 1). Utilities for early stage disease and treatment modalities, but not metastatic disease, varied with socio-demographic characteristics. One hundred and twenty-two of 156 subjects had utilities that maximized quality-adjusted life expectancy given stage II breast cancer with chemotherapy. Age over 50, black race, and low household income were associated with at least 5-fold lower odds of maximizing quality-adjusted life expectancy with chemotherapy, whereas women who were married or had a significant other were 4-fold more likely to maximize quality-adjusted life expectancy with chemotherapy. Differences in utility for breast cancer health states may partially explain the lower rate of adjuvant therapy for black, older, and less affluent women. Further work must clarify whether these differences result from health preference alone or reflect women's perceptions of sources of disparity, such as access to care, poor communication with providers, limitations in health knowledge or in obtaining social and workplace support during therapy.

Carbon Mineralization by Aqueous Precipitation for Beneficial Use of CO 2 from Flue Gas

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

Devenney, Martin; Gilliam, Ryan; Seeker, Randy

The objective of this project was to demonstrate an innovative process to mineralize CO 2 from flue gas directly to reactive carbonates and maximize the value and versatility of its beneficial use products. The program scope includes the design, construction, and testing of a CO 2 Conversion to Material Products (CCMP) Pilot Demonstration Plant utilizing CO 2 from the flue gas of a power production facility in Moss Landing, CA as well as flue gas from coal combustion. This final report details all development, analysis, design and testing of the project. Also included in the final report are an updatedmore » Techno-Economic Analysis and CO 2 Lifecycle Analysis. The subsystems included in the pilot demonstration plant are the mineralization subsystem, the Alkalinity Based on Low Energy (ABLE) subsystem, the waste calcium oxide processing subsystem, and the fiber cement board production subsystem. The fully integrated plant was proven to be capable of capturing CO 2 from various sources (gas and coal) and mineralizing it into a reactive calcium carbonate binder and subsequently producing commercial size (4ftx8ft) fiber cement boards. The final report provides a description of the “as built” design of these subsystems and the results of the commissioning activities that have taken place to confirm operability. The report also discusses the results of the fully integrated operation of the facility. Fiber cement boards have been produced in this facility exclusively using reactive calcium carbonate from captured CO 2 from flue gas. These boards meet all US and China appropriate acceptance standards. Use demonstrations for these boards are now underway.« less

Coordinated regulation of growth, activity and transcription in natural populations of the unicellular nitrogen-fixing cyanobacterium Crocosphaera.

PubMed

Wilson, Samuel T; Aylward, Frank O; Ribalet, Francois; Barone, Benedetto; Casey, John R; Connell, Paige E; Eppley, John M; Ferrón, Sara; Fitzsimmons, Jessica N; Hayes, Christopher T; Romano, Anna E; Turk-Kubo, Kendra A; Vislova, Alice; Armbrust, E Virginia; Caron, David A; Church, Matthew J; Zehr, Jonathan P; Karl, David M; DeLong, Edward F

2017-07-31

The temporal dynamics of phytoplankton growth and activity have large impacts on fluxes of matter and energy, yet obtaining in situ metabolic measurements of sufficient resolution for even dominant microorganisms remains a considerable challenge. We performed Lagrangian diel sampling with synoptic measurements of population abundances, dinitrogen (N 2 ) fixation, mortality, productivity, export and transcription in a bloom of Crocosphaera over eight days in the North Pacific Subtropical Gyre (NPSG). Quantitative transcriptomic analyses revealed clear diel oscillations in transcript abundances for 34% of Crocosphaera genes identified, reflecting a systematic progression of gene expression in diverse metabolic pathways. Significant time-lagged correspondence was evident between nifH transcript abundance and maximal N 2 fixation, as well as sepF transcript abundance and cell division, demonstrating the utility of transcriptomics to predict the occurrence and timing of physiological and biogeochemical processes in natural populations. Indirect estimates of carbon fixation by Crocosphaera were equivalent to 11% of net community production, suggesting that under bloom conditions this diazotroph has a considerable impact on the wider carbon cycle. Our cross-scale synthesis of molecular, population and community-wide data underscores the tightly coordinated in situ metabolism of the keystone N 2 -fixing cyanobacterium Crocosphaera, as well as the broader ecosystem-wide implications of its activities.

Sol-gel derived electrode materials for supercapacitor applications

NASA Astrophysics Data System (ADS)

Lin, Chuan

1998-12-01

Electrochemical capacitors have been receiving increasing interest in recent years for use in energy storage systems because of their high energy and power density and long cycle lifes. Possible applications of electrochemical capacitors include high power pulsed lasers, hybrid power system for electric vehicles, etc. In this dissertation, the preparation of electrode materials for use as electrochemical capacitors has been studied using the sol-gel process. The high surface area electrode materials explored in this work include a synthetic carbon xerogel for use in a double-layer capacitor, a cobalt oxide xerogel for use in a pseudocapacitor, and a carbon-ruthenium xerogel composite, which utilizes both double-layer and faradaic capacitances. The preparation conditions of these materials were investigated in detail to maximize the surface area and optimize the pore size so that more energy could be stored while minimizing mass transfer limitations. The microstructures of the materials were also correlated with their performance as electrochemical capacitors to improve their energy and power densities. Finally, an idealistic mathematical model, including both double-layer and faradaic processes, was developed and solved numerically. This model can be used to perform the parametric studies of an electrochemical capacitor so as to gain a better understanding of how the capacitor works and also how to improve cell operations and electrode materials design.

Characterization and optimization of schizophyllan production from date syrup.

PubMed

Jamshidian, Hajar; Shojaosadati, Seyed Abbas; Vilaplana, Francisco; Mousavi, Seyed Mohammad; Soudi, Mohammad Reza

2016-11-01

This study demonstrates the efficient utilization of low-cost agricultural substrates, particularly date syrup, by Schizophyllum commune ATCC 38548 for schizophyllan production. Initially, one factor-at-a-time method was used to find the best carbon and nitrogen sources for schizophyllan production. Subsequently, response surface methodology was employed to optimize the level of culture medium components to maximize substrate conversion yield and schizophyllan production in submerged culture. Maximum product yield (0.12g schizophyllan/g date syrup) and schizophyllan production (8.5g/l) were obtained at concentrations of date syrup and corn steep liquor, inoculum size and agitation rate at 7.02%w/v, 0.10%w/v, 7.68%v/v and 181rpm, respectively. Sugar composition analysis, FTIR, NMR and molar mass determination revealed the purity and molecular properties of recovered schizophyllan produced from date syrup as glycosidic linkage analysis showed three main schizophyllan characteristic peaks arising from the 3-linked, 3,6-linked and terminal glucose residues. Finally, process economic analysis suggested that use of date syrup and corn steep liquor as nutrients would result in approximately 6-fold reduction in cost of raw materials for schizophyllan production as compared to conventional carbon and nitrogen sources such as sucrose and malt extract. Copyright © 2016 Elsevier B.V. All rights reserved.

Creating Methane from Plastics: Recycling at a Lunar Outpost

NASA Technical Reports Server (NTRS)

Captain, Janine; Santiago, Eddie; Wheeler, Ray; Strayer, RIchard; Garland, Jay; Parrish, Clyde

2010-01-01

The high cost of re-supply from Earth demands resources to be utilized to the fullest extent for exploration missions. Recycling is a key technology that maximizes the available resources by converting waste products into useful commodities. One example of this is to convert crew member waste such as plastic packaging, food scraps, and human waste, into fuel. The ability to refuel on the lunar surface would reduce the vehicle mass during launch and provide excess payload capability. The goal of this project is to determine the feasibility of recycling waste into methane on the lunar outpost by performing engineering assessments and lab demonstrations of the technology. The first goal of the project was to determine how recycling could influence lunar exploration. Table I shows an estimation of the typical dried waste stream generated each day for a crew of four. Packaging waste accounts for nearly 86% of the dry waste stream and is a significant source of carbon on the lunar surface. This is important because methane (CH4) can be used as fuel and no other source of carbon is available on the lunar surface. With the initial assessment indicating there is sufficient resources in the waste stream to provide refueling capabilities, the project was designed to examine the conversion of plastics into methane.

Vitamin K catabolite inhibition of ovariectomy-induced bone loss: structure-activity relationship considerations.

PubMed

Soper, Robin J; Oguz, Cenk; Emery, Roger; Pitsillides, Andrew A; Hodges, Stephen J

2014-08-01

The potential benefit of vitamin K as a therapeutic in osteoporosis is controversial and the vitamin K regimen being used clinically (45 mg/day) employs doses that are many times higher than required to ensure maximal gamma-carboxylation of the vitamin K-dependent bone proteins. We therefore tested the hypothesis that vitamin K catabolites, 5-carbon (CAN5C) and 7-carbon carboxylic acid (CAN7C) aliphatic side-chain derivatives of the naphthoquinone moiety exert an osteotrophic role consistent with the treatment of osteoporosis. Osteoblast-like MG63 cell cultures were challenged with lipopolysaccharide and the levels of interleukin-6, an osteoclastogenic cytokine, measured with and without catabolites; low concentrations of CAN7C significantly inhibited interleukin-6 release, but CAN5C did not. In models of bone loss induced by ovariectomy or sciatic neurectomy in C57BL/6 mice, we found that the rarer CAN7C catabolite markedly restricted ovariectomy-induced bone loss and possibly limited sciatic neurectomy-induced bone loss. CAN7C activity depends on a free carboxylic acid and its particular side-chain structure. These in vivo data indicate for the first time that the clinical utility of vitamin K for osteoporosis may reside in an unusual catabolite. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fuel treatment effects on tree-based forest carbon storage and emissions under modeled wildfire scenarios

Treesearch

M. Hurteau; M. North

2009-01-01

Forests are viewed as a potential sink for carbon (C) that might otherwise contribute to climate change. It is unclear, however, how to manage forests with frequent fire regimes to maximize C storage while reducing C emissions from prescribed burns or wildfire. We modeled the effects of eight different fuel treatments on treebased C storage and release over a century,...

Role of vegetation and edaphic factors in controlling diversity and use of different carbon sources in semi-arid ecosystems

NASA Astrophysics Data System (ADS)

Lohse, K. A.; McLain, J. E.; Harman, C. J.; Sivapalan, M.; Troch, P. A.

2010-12-01

Microbially-mediated soil carbon cycling is closely linked to soil moisture and temperature. Climate change is predicted to increase intra-annual precipitation variability (i.e. less frequent yet more intense precipitation events) and alter biogeochemical processes due to shifts in soil moisture dynamics and inputs of carbon. However, the responses of soil biology and chemistry to predicted climate change, and their concomitant feedbacks on ecosystem productivity and biogeochemical processes are poorly understood. We collected soils at three different elevations in the Santa Catalina Mountains, AZ and quantified carbon utilization during pre-monsoon precipitation conditions. Contrasting parent materials (schist and granite) were paired at each elevation. We expected climate to determine the overall activity of soil fungal and bacterial communities and diversity of soil C utilization, and differences in parent material to modify these responses through controls on soil physical properties. We used EcoPlateTM C utilization assays to determine the relative abundance of soil bacterial and fungal populations and rate and diversity of carbon utilization. Additional plates were incubated with inhibitors selective to fungal or bacterial activity to assess relative contribution of these microbial groups to overall C utilization. We analyzed soils for soil organic matter, total C and N, particle size analysis and soil moisture content via both gravimetric and volumetric methods to assess the influences of soil physical and chemical properties on the measured biological responses. Consistent with our expectations, overall microbial activity was highest at the uppermost conifer elevation sites compared to the middle and lower elevation sites. In contrast to our expectations, however, overall activity was lower at the mid elevation oak woodland sites compared to the low elevation desert sites. Also consistent with our expectations was the observation that overall activities were consistently higher in schist parent material compared to granite. Though differences between canopy and intercanopy carbon utilization were subtle, the diversity of carbon utilization differed, suggesting a potential role of root exudates in governing C utilization in these semiarid soils. Findings from this study suggest that soil physical properties due to parent material have primary impacts in constraining microbial growth and carbon utilization under changing climate conditions.

Low Carbon Design Research on the Space Layout Types of Office Buildings

NASA Astrophysics Data System (ADS)

Xia, Bing

2018-01-01

It is beneficial to find out the relationship of the spatial layout and low-carbon design in order to reduce buildings’ carbon emissions in the conceptual design phase. This paper analyzes and compares shape coefficient values, annual energy consumption and lighting performance of office buildings of different space layout types in Shanghai. Based on morphological characteristics of different types, the study also analyzes and presents low-carbon design strategies for each single type. This study assumes that architects should conduct passive and active design according to the specific building space layout, so that to make best use of the advantages and bypassing the disadvantages, in order to maximally reduce buildings’ carbon emissions.

Optimal weight based on energy imbalance and utility maximization

NASA Astrophysics Data System (ADS)

Sun, Ruoyan

2016-01-01

This paper investigates the optimal weight for both male and female using energy imbalance and utility maximization. Based on the difference of energy intake and expenditure, we develop a state equation that reveals the weight gain from this energy gap. We ​construct an objective function considering food consumption, eating habits and survival rate to measure utility. Through applying mathematical tools from optimal control methods and qualitative theory of differential equations, we obtain some results. For both male and female, the optimal weight is larger than the physiologically optimal weight calculated by the Body Mass Index (BMI). We also study the corresponding trajectories to steady state weight respectively. Depending on the value of a few parameters, the steady state can either be a saddle point with a monotonic trajectory or a focus with dampened oscillations.

Budget Allocation in a Competitive Communication Spectrum Economy

NASA Astrophysics Data System (ADS)

Lin, Ming-Hua; Tsai, Jung-Fa; Ye, Yinyu

2009-12-01

This study discusses how to adjust "monetary budget" to meet each user's physical power demand, or balance all individual utilities in a competitive "spectrum market" of a communication system. In the market, multiple users share a common frequency or tone band and each of them uses the budget to purchase its own transmit power spectra (taking others as given) in maximizing its Shannon utility or pay-off function that includes the effect of interferences. A market equilibrium is a budget allocation, price spectrum, and tone power distribution that independently and simultaneously maximizes each user's utility. The equilibrium conditions of the market are formulated and analyzed, and the existence of an equilibrium is proved. Computational results and comparisons between the competitive equilibrium and Nash equilibrium solutions are also presented, which show that the competitive market equilibrium solution often provides more efficient power distribution.

Speed over efficiency: locusts select body temperatures that favour growth rate over efficient nutrient utilization

PubMed Central

Miller, Gabriel A.; Clissold, Fiona J.; Mayntz, David; Simpson, Stephen J.

2009-01-01

Ectotherms have evolved preferences for particular body temperatures, but the nutritional and life-history consequences of such temperature preferences are not well understood. We measured thermal preferences in Locusta migratoria (migratory locusts) and used a multi-factorial experimental design to investigate relationships between growth/development and macronutrient utilization (conversion of ingesta to body mass) as a function of temperature. A range of macronutrient intake values for insects at 26, 32 and 38°C was achieved by offering individuals high-protein diets, high-carbohydrate diets or a choice between both. Locusts placed in a thermal gradient selected temperatures near 38°C, maximizing rates of weight gain; however, this enhanced growth rate came at the cost of poor protein and carbohydrate utilization. Protein and carbohydrate were equally digested across temperature treatments, but once digested both macronutrients were converted to growth most efficiently at the intermediate temperature (32°C). Body temperature preference thus yielded maximal growth rates at the expense of efficient nutrient utilization. PMID:19625322

Active inference and epistemic value.

PubMed

Friston, Karl; Rigoli, Francesco; Ognibene, Dimitri; Mathys, Christoph; Fitzgerald, Thomas; Pezzulo, Giovanni

2015-01-01

We offer a formal treatment of choice behavior based on the premise that agents minimize the expected free energy of future outcomes. Crucially, the negative free energy or quality of a policy can be decomposed into extrinsic and epistemic (or intrinsic) value. Minimizing expected free energy is therefore equivalent to maximizing extrinsic value or expected utility (defined in terms of prior preferences or goals), while maximizing information gain or intrinsic value (or reducing uncertainty about the causes of valuable outcomes). The resulting scheme resolves the exploration-exploitation dilemma: Epistemic value is maximized until there is no further information gain, after which exploitation is assured through maximization of extrinsic value. This is formally consistent with the Infomax principle, generalizing formulations of active vision based upon salience (Bayesian surprise) and optimal decisions based on expected utility and risk-sensitive (Kullback-Leibler) control. Furthermore, as with previous active inference formulations of discrete (Markovian) problems, ad hoc softmax parameters become the expected (Bayes-optimal) precision of beliefs about, or confidence in, policies. This article focuses on the basic theory, illustrating the ideas with simulations. A key aspect of these simulations is the similarity between precision updates and dopaminergic discharges observed in conditioning paradigms.

A theoretical framework to predict the most likely ion path in particle imaging.

PubMed

Collins-Fekete, Charles-Antoine; Volz, Lennart; Portillo, Stephen K N; Beaulieu, Luc; Seco, Joao

2017-03-07

In this work, a generic rigorous Bayesian formalism is introduced to predict the most likely path of any ion crossing a medium between two detection points. The path is predicted based on a combination of the particle scattering in the material and measurements of its initial and final position, direction and energy. The path estimate's precision is compared to the Monte Carlo simulated path. Every ion from hydrogen to carbon is simulated in two scenarios, (1) where the range is fixed and (2) where the initial velocity is fixed. In the scenario where the range is kept constant, the maximal root-mean-square error between the estimated path and the Monte Carlo path drops significantly between the proton path estimate (0.50 mm) and the helium path estimate (0.18 mm), but less so up to the carbon path estimate (0.09 mm). However, this scenario is identified as the configuration that maximizes the dose while minimizing the path resolution. In the scenario where the initial velocity is fixed, the maximal root-mean-square error between the estimated path and the Monte Carlo path drops significantly between the proton path estimate (0.29 mm) and the helium path estimate (0.09 mm) but increases for heavier ions up to carbon (0.12 mm). As a result, helium is found to be the particle with the most accurate path estimate for the lowest dose, potentially leading to tomographic images of higher spatial resolution.

Two-dimensional isobutyl acetate production pathways to improve carbon yield

PubMed Central

Tashiro, Yohei; Desai, Shuchi H.; Atsumi, Shota

2015-01-01

For an economically competitive biological process, achieving high carbon yield of a target chemical is crucial. In biochemical production, pyruvate and acetyl-CoA are primary building blocks. When sugar is used as the sole biosynthetic substrate, acetyl-CoA is commonly generated by pyruvate decarboxylation. However, pyruvate decarboxylation during acetyl-CoA formation limits the theoretical maximum carbon yield (TMCY) by releasing carbon, and in some cases also leads to redox imbalance. To avoid these problems, we describe here the construction of a metabolic pathway that simultaneously utilizes glucose and acetate. Acetate is utilized to produce acetyl-CoA without carbon loss or redox imbalance. We demonstrate the utility of this approach for isobutyl acetate (IBA) production, wherein IBA production with glucose and acetate achieves a higher carbon yield than with either sole carbon source. These results highlight the potential for this multiple carbon source approach to improve the TMCY and balance redox in biosynthetic pathways. PMID:26108471

Time-Extended Policies in Mult-Agent Reinforcement Learning

NASA Technical Reports Server (NTRS)

Tumer, Kagan; Agogino, Adrian K.

2004-01-01

Reinforcement learning methods perform well in many domains where a single agent needs to take a sequence of actions to perform a task. These methods use sequences of single-time-step rewards to create a policy that tries to maximize a time-extended utility, which is a (possibly discounted) sum of these rewards. In this paper we build on our previous work showing how these methods can be extended to a multi-agent environment where each agent creates its own policy that works towards maximizing a time-extended global utility over all agents actions. We show improved methods for creating time-extended utilities for the agents that are both "aligned" with the global utility and "learnable." We then show how to crate single-time-step rewards while avoiding the pi fall of having rewards aligned with the global reward leading to utilities not aligned with the global utility. Finally, we apply these reward functions to the multi-agent Gridworld problem. We explicitly quantify a utility's learnability and alignment, and show that reinforcement learning agents using the prescribed reward functions successfully tradeoff learnability and alignment. As a result they outperform both global (e.g., team games ) and local (e.g., "perfectly learnable" ) reinforcement learning solutions by as much as an order of magnitude.

Creating an Agent Based Framework to Maximize Information Utility

DTIC Science & Technology

2008-03-01

information utility may be a qualitative description of the information, where one would expect the adjectives low value, fair value , high value. For...operations. Information in this category may have a fair value rating. Finally, many seemingly unrelated events, such as reports of snipers in buildings

Bacterial carbon utilization in vertical subsurface flow constructed wetlands.

PubMed

Tietz, Alexandra; Langergraber, Günter; Watzinger, Andrea; Haberl, Raimund; Kirschner, Alexander K T

2008-03-01

Subsurface vertical flow constructed wetlands with intermittent loading are considered as state of the art and can comply with stringent effluent requirements. It is usually assumed that microbial activity in the filter body of constructed wetlands, responsible for the removal of carbon and nitrogen, relies mainly on bacterially mediated transformations. However, little quantitative information is available on the distribution of bacterial biomass and production in the "black-box" constructed wetland. The spatial distribution of bacterial carbon utilization, based on bacterial (14)C-leucine incorporation measurements, was investigated for the filter body of planted and unplanted indoor pilot-scale constructed wetlands, as well as for a planted outdoor constructed wetland. A simple mass-balance approach was applied to explain the bacterially catalysed organic matter degradation in this system by comparing estimated bacterial carbon utilization rates with simultaneously measured carbon reduction values. The pilot-scale constructed wetlands proved to be a suitable model system for investigating microbial carbon utilization in constructed wetlands. Under an ideal operating mode, the bulk of bacterial productivity occurred within the first 10cm of the filter body. Plants seemed to have no significant influence on productivity and biomass of bacteria, as well as on wastewater total organic carbon removal.

Evaluating the Suitability of Management Strategies of Pure Norway Spruce Forests in the Black Forest Area of Southwest Germany for Adaptation to or Mitigation of Climate Change

NASA Astrophysics Data System (ADS)

Yousefpour, Rasoul; Hanewinkel, Marc; Le Moguédec, Gilles

2010-02-01

The study deals with the problem of evaluating management strategies for pure stands of Norway spruce ( Picea abies Karst) to balance adaptation to and mitigation of climate change, taking into account multiple objectives of a forest owner. A simulation and optimization approach was used to evaluate the management of a 1000 ha model Age-Class forest, representing the age-class distribution of an area of 66,000 ha of pure Norway spruce forests in the Black Forest region of Southwest Germany. Eight silvicultural scenarios comprising five forest conversion schemes which were interpreted as “adaptation” strategies which aims at increasing the proportion of Beech, that is expected to better cope with climate change than the existing Norway spruce, and three conventional strategies including a “Do-nothing” alternative classified as “mitigation”, trying to keep rather higher levels of growing stock of spruce, were simulated using the empirical growth simulator BWINPro-S. A linear programming approach was adapted to simultaneously maximize the net present values of carbon sequestration and timber production subject to the two constraints of wood even flow and partial protection of the oldest (nature protection). The optimized plan, with the global utility of 11,687 €/ha in forty years, allocated a combination of silvicultural scenarios to the entire forest area. Overall, strategies classified as “mitigation” were favored, while strategies falling into the “adaptation”-category were limited to the youngest age-classes in the optimal solution. Carbon sequestration of the “Do-nothing” alternative was between 1.72 and 1.85 million tons higher than the other alternatives for the entire forest area while the differences between the adaptation and mitigation approaches were approximately 133,000 tons. Sensitivity analysis showed that a carbon price of 21 €/ t is the threshold at which carbon sequestration is promoted, while an interest rate of above 2% would decrease the amount of carbon.

SU-E-T-771: Two Dimensional Raman Mapping of Carbon Bonds of Radiochromic Films: An Approach to Micro-Dosimetry

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

Heo, T; Ye, S

2015-06-15

Purpose: To study a feasibility of micro-dosimetry with high dose-sensitivity and resolution using two-dimensional Raman mapping on the basis of carbon bonds concentration of radiochromic films Methods: Unlaminated EBT3 films with the purpose of maximal Raman data acquisition were irradiated by 6 MV beam from 5 MU to 1000 MU at the reference condition. Each film was irradiated with shielding material of lead blocking on the half of film as well as the jaw open in half for distinct dose contrast. Raman peaks of 2070 cm-1, 2095 cm-1, and 2115 cm-1 were major subjects to study, which are assumed tomore » be the spectroscopy of carbon triple bonds of monomers, carbon double bonds of polymers, and carbon triple bonds of polymers, respectively. Laser exposure for Raman spectroscopy generated peak’s trend due to polymerization by laser output and this trend was utilized to find out basic peaks related to polymerization process. The relative dose contrast in each one film was detected by Raman spectroscopy with the aid of an auto-scanning stage, comparing the dose contrast between non-irradiated area and irradiated area. Raman spatial resolution was enhanced up to 20 micrometers, assuming the spatial uniformity of radio¬active rod-shaped LiPCDA crystals. An optical scanner with 9600 dpi was used to scan the red-channel intensity to read the dose contrast for 5 MU delivered film. Results: The peak intensity for Raman wavenumber of 2070 cm-1 was used for mapping since it reflected the different peak intensities based on polymerization degree by irradiation. Dose contrast from 1000MU to 5 MU was distinguished by Raman mapping analysis, whereas optical intensity of red-channel didn’t show any difference. Conclusion: In consideration of laser effect, the quantitative analysis based on raw data of Raman mapping could provide more statistically reliable dosimetry than point measurements.« less

Choice Inconsistencies among the Elderly: Evidence from Plan Choice in the Medicare Part D Program: Comment.

PubMed

Ketcham, Jonathan D; Kuminoff, Nicolai V; Powers, Christopher A

2016-12-01

Consumers' enrollment decisions in Medicare Part D can be explained by Abaluck and Gruber’s (2011) model of utility maximization with psychological biases or by a neoclassical version of their model that precludes such biases. We evaluate these competing hypotheses by applying nonparametric tests of utility maximization and model validation tests to administrative data. We find that 79 percent of enrollment decisions from 2006 to 2010 satisfied basic axioms of consumer theory under the assumption of full information. The validation tests provide evidence against widespread psychological biases. In particular, we find that precluding psychological biases improves the structural model's out-of-sample predictions for consumer behavior.

Gas Exchange of Algae

PubMed Central

Ammann, Elizabeth C. B.; Lynch, Victoria H.

1967-01-01

The oxygen production of a photosynthetic gas exchanger containing Chlorella pyrenoidosa (1% packed cell volume) was measured when various concentrations of carbon dioxide were present within the culture unit. The internal carbon dioxide concentrations were obtained by manipulating the entrance gas concentration and the flow rate. Carbon dioxide percentages were monitored by means of electrodes placed directly in the nutrient medium. The concentration of carbon dioxide in the nutrient medium which produced maximal photosynthesis was in the range of 1.5 to 2.5% by volume. Results were unaffected by either the level of carbon dioxide in the entrance gas or the rate of gas flow. Entrance gases containing 2% carbon dioxide flowing at 320 ml/min, 3% carbon dioxide at 135 ml/min, and 4% carbon dioxide at 55 ml/min yielded optimal carbon dioxide concentrations in the particular unit studied. By using carbon dioxide electrodes implanted directly in the gas exchanger to optimize the carbon dioxide concentration throughout the culture medium, it should be possible to design more efficient large-scale units. PMID:4382391

Sequence, assembly and annotation of the maize W22 genome

USDA-ARS?s Scientific Manuscript database

Since its adoption by Brink and colleagues in the 1950s and 60s, the maize W22 inbred has been utilized extensively to understand fundamental genetic and epigenetic processes such recombination, transposition and paramutation. To maximize the utility of W22 in gene discovery, we have Illumina sequen...

76 FR 49473 - Petition to Maximize Practical Utility of List 1 Chemicals Screened Through EPA's Endocrine...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-10

... Utility of List 1 Chemicals Screened Through EPA's Endocrine Disruptor Screening Program; Notice of... to the test orders issued under the Endocrine Disruptor Screening Program. DATES: Comments must be... testing of chemical substances for potential endocrine effects. Potentially affected entities, identified...

Asymmetric homologation of boronic esters bearing azido and silyloxy substituents.

PubMed

Singh, R P; Matteson, D S

2000-10-06

In the asymmetric homologation of boronic esters with a (dihalomethyl)lithium, substituents that can bind metal cations tend to interfere. Accordingly, we undertook the introduction of weakly basic oxygen and nitrogen substituents into boronic esters in order to maximize the efficiency of multistep syntheses utilizing this chemistry. Silyloxy boronic esters cannot be made efficiently by direct substitution, but a (hydroxymethyl)boronic ester has been silylated in the usual manner. Conversion of alpha-halo boronic esters to alpha-azido boronic esters has been carried out with sodium azide and a tetrabutylammonium salt as phase-transfer catalyst in a two-phase system with water and either nitromethane or ethyl acetate. These are safer solvents than the previously used dichloromethane, which can form an explosive byproduct with azide ion. Boronic esters containing silyloxy or alkoxy and azido substituents have been shown to react efficiently with (dihalomethyl)lithiums, resulting in efficient asymmetric insertion of the halomethyl group into the carbon-boron bond.

Effects of hydrogen peroxide feeding strategies on the photochemical degradation of polyvinyl alcohol.

PubMed

Hamad, Dina; Dhib, Ramdhane; Mehrvar, Mehrab

2016-11-01

The performance of batch and fed-batch photoreactors with that of continuous photoreactor for the treatment of aqueous polyvinyl alcohol (PVA) solutions is compared. Hydrogen peroxide feeding strategies, residence time, and [H2O2]/[PVA] mass ratio are examined for their impacts on the molecular weight distribution (MWD) of PVA and the total organic carbon (TOC) removal. The results prove that a continuous addition of H2O2 during the degradation reaction ensures the utilization of the produced radicals to minimize the oxidant consumption and maximize the TOC removal and the PVA degradation in a short irradiation time. Also, the MWD of PVA is found to be bimodal and shifted towards lower molecular weights with small shoulder peak indicating a progressive disappearance of the higher molecular weight fractions that is in accordance with the random chains scission mechanism. Besides, the hydrogen peroxide feeding strategies are found to have a great effect on the reduction in H2O2 residuals in the effluent.

Development of a Fully Automated Guided Wave System for In-Process Cure Monitoring of CFRP Composite Laminates

NASA Technical Reports Server (NTRS)

Hudson, Tyler B.; Hou, Tan-Hung; Grimsley, Brian W.; Yaun, Fuh-Gwo

2016-01-01

A guided wave-based in-process cure monitoring technique for carbon fiber reinforced polymer (CFRP) composites was investigated at NASA Langley Research Center. A key cure transition point (vitrification) was identified and the degree of cure was monitored using metrics such as amplitude and time of arrival (TOA) of guided waves. Using an automated system preliminarily developed in this work, high-temperature piezoelectric transducers were utilized to interrogate a twenty-four ply unidirectional composite panel fabricated from Hexcel (Registered Trademark) IM7/8552 prepreg during cure. It was shown that the amplitude of the guided wave increased sharply around vitrification and the TOA curve possessed an inverse relationship with degree of cure. The work is a first step in demonstrating the feasibility of transitioning the technique to perform in-process cure monitoring in an autoclave, defect detection during cure, and ultimately a closed-loop process control to maximize composite part quality and consistency.

Stable carbonous catalyst particles and method for making and utilizing same

DOEpatents

Ganguli, Partha S.; Comolli, Alfred G.

2005-06-14

Stable carbonous catalyst particles composed of an inorganic catalytic metal/metal oxide powder and a carbonaceous binder material are formed having a basic inner substantially uniform-porous carbon coating of the catalytic powder, and may include an outer porous carbon coating layer. Suitable inorganic catalytic powders include zinc-chromite (ZnO/Cr.sub.2 03) and suitable carbonaceous liquid binders having molecular weight of 200-700 include partially polymerized furfuryl alcohol, which are mixed together, shaped and carbonized and partially oxidized at elevated temperature. Such stable carbonous catalyst particles such as 0.020-0.100 inch (0.51-2.54 mm) diameter extrudates, have total carbon content of 2-25 wt. % and improved crush strength of 1.0-5 1b/mn, 50-300 m.sup.2 /g surface area, and can be advantageously utilized in fixed bed or ebullated/fluidized bed reactor operations. This invention also includes method steps for making the stable carbonous catalyst particles having improved particle strength and catalytic activity, and processes for utilizing the active stable carbonous carbon-coated catalysts such as for syn-gas reactions in ebullated/fluidized bed reactors for producing alcohol products and Fischer-Tropsch synthesis liquid products.

Algae Cultivation for Carbon Capture and Utilization Workshop Summary Report

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

None, None

The Algae Cultivation for Carbon Capture and Utilization Workshop Summary Report summarizes a workshop hosted by the U.S. Department of Energy's Bioenergy Technologies Office on May 23–24, 2017, in Orlando, Florida. The event gathered stakeholder input through facilitated discussions focused on innovative technologies and business strategies for growing algae on waste carbon dioxide resources.

Algae Cultivation for Carbon Capture and Utilization Workshop Summary Report

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

None, None

2017-05-01

The Algae Cultivation for Carbon Capture and Utilization Workshop Summary Report summarizes a workshop hosted by the U.S. Department of Energy's Bioenergy Technologies Office on May 23–24, 2017, in Orlando, Florida. The event gathered stakeholder input through facilitated discussions focused on innovative technologies and business strategies for growing algae on waste carbon dioxide resources.

Low Temperature Consolidation of Micro/Nanosilver Die-Attach Preforms

NASA Astrophysics Data System (ADS)

McCoppin, Jared; Reitz, Thomas L.; Miller, Ryan; Vijwani, Hema; Mukhopadhyay, Sharmila; Young, Daniel

2014-09-01

Organically passivated silver nanopowder paste-based sintering is considered a promising solution for die-attach in high temperature power and sensing electronic devices. However, oxygen requirements during burnout and inherently high shrinkage rates limit their use to small die sizes. This work reports an alternative fabrication method that resolves decomposition and shrinkage issues of the die-attach by utilizing a prestressed optimized tape cast mixture of micro- and nanosilver particles with a polypropylene carbonate binder. The effects of prestressing, micro/nanosilver bimodal distribution, and polymer content on resulting microstructure and shear strength were investigated. Prior to application as a die-attach, uniaxial compression of the tape was found to significantly decrease shrinkage and improve green strength. This pre-stressing strategy allows for a decoupling of the resulting die-attach materials properties from the pressure applied during assembly. Bimodal mixtures consisting of 1-3 μm spherical powders with nanosilver resulted in shear strengths comparable to those of pure nanosilver. Shear strength decreased as bimodal particle size increased above 5 μm. A polymer content of ˜10 wt.% polypropylene carbonate combined with prestressing was identified as optimal for maximizing die-attach shear strength while still maintaining pliability and formability. Tape casts that were prestressed to 212 MPa by uniaxially compression and formulated with 10 wt.% of polypropylene carbonate resulted in a die-attach material with a shear strength of 54 MPa when sintered. These materials were used to demonstrate void-free 25-mm2 die-attach assemblies, suggesting that tape cast micro/nanosilver materials may be a promising die-attach method for high temperature and large-area electronics devices.

Metabolic Architecture of the Cereal Grain and Its Relevance to Maximize Carbon Use Efficiency1[OPEN

PubMed Central

Rolletschek, Hardy; Grafahrend-Belau, Eva; Munz, Eberhard; Radchuk, Volodymyr; Kartäusch, Ralf; Tschiersch, Henning; Melkus, Gerd; Schreiber, Falk; Jakob, Peter M.; Borisjuk, Ljudmilla

2015-01-01

Here, we have characterized the spatial heterogeneity of the cereal grain’s metabolism and demonstrated how, by integrating a distinct set of metabolic strategies, the grain has evolved to become an almost perfect entity for carbon storage. In vivo imaging revealed light-induced cycles in assimilate supply toward the ear/grain of barley (Hordeum vulgare) and wheat (Triticum aestivum). In silico modeling predicted that, in the two grain storage organs (the endosperm and embryo), the light-induced shift in solute influx does cause adjustment in metabolic flux without changes in pathway utilization patterns. The enveloping, leaf-like pericarp, in contrast, shows major shifts in flux distribution (starch metabolism, photosynthesis, remobilization, and tricarboxylic acid cycle activity) allow to refix 79% of the CO2 released by the endosperm and embryo, allowing the grain to achieve an extraordinary high carbon conversion efficiency of 95%. Shading experiments demonstrated that ears are autonomously able to raise the influx of solutes in response to light, but with little effect on the steady-state levels of metabolites or transcripts or on the pattern of sugar distribution within the grain. The finding suggests the presence of a mechanism(s) able to ensure metabolic homeostasis in the face of short-term environmental fluctuation. The proposed multicomponent modeling approach is informative for predicting the metabolic effects of either an altered level of incident light or a momentary change in the supply of sucrose. It is therefore of potential value for assessing the impact of either breeding and/or biotechnological interventions aimed at increasing grain yield. PMID:26395842

Metabolic Architecture of the Cereal Grain and Its Relevance to Maximize Carbon Use Efficiency.

PubMed

Rolletschek, Hardy; Grafahrend-Belau, Eva; Munz, Eberhard; Radchuk, Volodymyr; Kartäusch, Ralf; Tschiersch, Henning; Melkus, Gerd; Schreiber, Falk; Jakob, Peter M; Borisjuk, Ljudmilla

2015-11-01

Here, we have characterized the spatial heterogeneity of the cereal grain's metabolism and demonstrated how, by integrating a distinct set of metabolic strategies, the grain has evolved to become an almost perfect entity for carbon storage. In vivo imaging revealed light-induced cycles in assimilate supply toward the ear/grain of barley (Hordeum vulgare) and wheat (Triticum aestivum). In silico modeling predicted that, in the two grain storage organs (the endosperm and embryo), the light-induced shift in solute influx does cause adjustment in metabolic flux without changes in pathway utilization patterns. The enveloping, leaf-like pericarp, in contrast, shows major shifts in flux distribution (starch metabolism, photosynthesis, remobilization, and tricarboxylic acid cycle activity) allow to refix 79% of the CO2 released by the endosperm and embryo, allowing the grain to achieve an extraordinary high carbon conversion efficiency of 95%. Shading experiments demonstrated that ears are autonomously able to raise the influx of solutes in response to light, but with little effect on the steady-state levels of metabolites or transcripts or on the pattern of sugar distribution within the grain. The finding suggests the presence of a mechanism(s) able to ensure metabolic homeostasis in the face of short-term environmental fluctuation. The proposed multicomponent modeling approach is informative for predicting the metabolic effects of either an altered level of incident light or a momentary change in the supply of sucrose. It is therefore of potential value for assessing the impact of either breeding and/or biotechnological interventions aimed at increasing grain yield. © 2015 American Society of Plant Biologists. All Rights Reserved.

Carbon dioxide conversion over carbon-based nanocatalysts.

PubMed

Khavarian, Mehrnoush; Chai, Siang-Piao; Mohamed, Abdul Rahman

2013-07-01

The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity.

Solar gasification of biomass: design and characterization of a molten salt gasification reactor

NASA Astrophysics Data System (ADS)

Hathaway, Brandon Jay

The design and implementation of a prototype molten salt solar reactor for gasification of biomass is a significant milestone in the development of a solar gasification process. The reactor developed in this work allows for 3 kWth operation with an average aperture flux of 1530 suns at salt temperatures of 1200 K with pneumatic injection of ground or powdered dry biomass feedstocks directly into the salt melt. Laboratory scale experiments in an electrically heated reactor demonstrate the benefits of molten salt and the data was evaluated to determine the kinetics of pyrolysis and gasification of biomass or carbon in molten salt. In the presence of molten salt overall gas yields are increased by up to 22%; pyrolysis rates double due to improved heat transfer, while carbon gasification rates increase by an order of magnitude. Existing kinetic models for cellulose pyrolysis fit the data well, while carbon gasification in molten salt follows kinetics modeled with a 2/3 order shrinking-grain model with a pre-exponential factor of 1.5*106 min-1 and activation energy of 158 kJ/mol. A reactor concept is developed based around a concentric cylinder geometry with a cavity-style solar receiver immersed within a volume of molten carbonate salt. Concentrated radiation delivered to the cavity is absorbed in the cavity walls and transferred via convection to the salt volume. Feedstock is delivered into the molten salt volume where biomass gasification reactions will be carried out producing the desired product gas. The features of the cavity receiver/reactor concept are optimized based on modeling of the key physical processes. The cavity absorber geometry is optimized according to a parametric survey of radiative exchange using a Monte Carlo ray tracing model, resulting in a cavity design that achieves absorption efficiencies of 80%-90%. A parametric survey coupling the radiative exchange simulations to a CFD model of molten salt natural convection is used to size the annulus containing the molten salt to maximize utilization of absorbed solar energy, resulting in a predicted utilization efficiency of 70%. Finite element analysis was used to finalize the design to achieve acceptable thermal stresses less than 34.5 MPa to avoid material creep.

Estimating the carbon budget and maximizing future carbon uptake for a temperate forest region in the U.S.

PubMed Central

2012-01-01

Background Forests of the Midwest U.S. provide numerous ecosystem services. Two of these, carbon sequestration and wood production, are often portrayed as conflicting. Currently, carbon management and biofuel policies are being developed to reduce atmospheric CO2 and national dependence on foreign oil, and increase carbon storage in ecosystems. However, the biological and industrial forest carbon cycles are rarely studied in a whole-system structure. The forest system carbon balance is the difference between the biological (net ecosystem production) and industrial (net emissions from forest industry) forest carbon cycles, but to date this critical whole system analysis is lacking. This study presents a model of the forest system, uses it to compute the carbon balance, and outlines a methodology to maximize future carbon uptake in a managed forest region. Results We used a coupled forest ecosystem process and forest products life cycle inventory model for a regional temperate forest in the Midwestern U.S., and found the net system carbon balance for this 615,000 ha forest was positive (2.29 t C ha-1 yr-1). The industrial carbon budget was typically less than 10% of the biological system annually, and averaged averaged 0.082 t C ha-1 yr-1. Net C uptake over the next 100-years increased by 22% or 0.33 t C ha-1 yr-1 relative to the current harvest rate in the study region under the optized harvest regime. Conclusions The forest’s biological ecosystem current and future carbon uptake capacity is largely determined by forest harvest practices that occurred over a century ago, but we show an optimized harvesting strategy would increase future carbon sequestration, or wood production, by 20-30%, reduce long transportation chain emissions, and maintain many desirable stand structural attributes that are correlated to biodiversity. Our results for this forest region suggest that increasing harvest over the next 100 years increases the strength of the carbon sink, and that carbon sequestration and wood production are not conflicting for this particular forest ecosystem. The optimal harvest strategy found here may not be the same for all forests, but the methodology is applicable anywhere sufficient forest inventory data exist. PMID:22713794

The metabolism of the Antartic crytoendolithic microbiota

NASA Technical Reports Server (NTRS)

Vestal, J. Robie

1989-01-01

The carbon metabolism of the cryptoendolithic microbiota in sandstones from the Ross Desert region of Antarctica was studied in situ and in vitro. Organic and inorganic compounds were metabolized by the microbiota, with bicarbonate being metabolized maximally in the light. There was a linear response of photosynthesis to light up to 200 to 300 micromole photons/sq m/s. The community photosynthetic response to temperature was a minimum at -5 C, two optima at +5 and +15 C and a maximum at +35 C. Photosynthetic metabolism occurred maximally in the presence of liquid water, but could occur in an environment of water vapor. Biomass of the cryptoendolithic microbiota was measured as the amount of lipid phosphate present. The in situ biomass ranged from 1.92 to 3.26 g carbon/sq m of rock and 2 orders of magnitude less than epilithic lichen microbiota from Antarctica in a location 7 degrees more north in latitude. With these data, it was possible to calculate primary production and carbon turnover in this simple microbiota. Production values ranged from 0.108 to 4.41 mg carbon/sq m/yr, while carbon turnover values ranged from 576 to 23,520 years. These values are the lowest and longest yet recorded for any ecosystem on Earth. If life did evolve on Mars to the level of prokaryotes or primitive eukaryotes, the possibility that the organisms retreated, to the protection of the inside of the rock so that metabolism could continue during planetary cooling, cannot be overlooked.

Effect of electrode mass ratio on aging of activated carbon based supercapacitors utilizing organic electrolytes

NASA Astrophysics Data System (ADS)

Cericola, D.; Kötz, R.; Wokaun, A.

2011-03-01

The accelerated degradation of carbon based supercapacitors utilizing 1 M Et4NBF4 in acetonitrile and in propylene carbonate as electrolyte is investigated for a constant cell voltage of 3.5 V as a function of the positive over total electrode mass ratio. The degradation rate of the supercapacitor using acetonitrile as a solvent can be decreased by increasing the mass of the positive electrode. With a mass ratio (positive electrode mass/total electrode mass) of 0.65 the degradation rate is minimum. For the capacitor utilizing propylene carbonate as a solvent a similar effect was observed. The degradation rate was smallest for a mass ratio above 0.5.

Acidotolerant Bacteria and Fungi as a Sink of Methanol-Derived Carbon in a Deciduous Forest Soil

PubMed Central

Morawe, Mareen; Hoeke, Henrike; Wissenbach, Dirk K.; Lentendu, Guillaume; Wubet, Tesfaye; Kröber, Eileen; Kolb, Steffen

2017-01-01

Methanol is an abundant atmospheric volatile organic compound that is released from both living and decaying plant material. In forest and other aerated soils, methanol can be consumed by methanol-utilizing microorganisms that constitute a known terrestrial sink. However, the environmental factors that drive the biodiversity of such methanol-utilizers have been hardly resolved. Soil-derived isolates of methanol-utilizers can also often assimilate multicarbon compounds as alternative substrates. Here, we conducted a comparative DNA stable isotope probing experiment under methylotrophic (only [13C1]-methanol was supplemented) and combined substrate conditions ([12C1]-methanol and alternative multi-carbon [13Cu]-substrates were simultaneously supplemented) to (i) identify methanol-utilizing microorganisms of a deciduous forest soil (European beech dominated temperate forest in Germany), (ii) assess their substrate range in the soil environment, and (iii) evaluate their trophic links to other soil microorganisms. The applied multi-carbon substrates represented typical intermediates of organic matter degradation, such as acetate, plant-derived sugars (xylose and glucose), and a lignin-derived aromatic compound (vanillic acid). An experimentally induced pH shift was associated with substantial changes of the diversity of active methanol-utilizers suggesting that soil pH was a niche-defining factor of these microorganisms. The main bacterial methanol-utilizers were members of the Beijerinckiaceae (Bacteria) that played a central role in a detected methanol-based food web. A clear preference for methanol or multi-carbon substrates as carbon source of different Beijerinckiaceae-affiliated phylotypes was observed suggesting a restricted substrate range of the methylotrophic representatives. Apart from Bacteria, we also identified the yeasts Cryptococcus and Trichosporon as methanol-derived carbon-utilizing fungi suggesting that further research is needed to exclude or prove methylotrophy of these fungi. PMID:28790984

A metabolic core model elucidates how enhanced utilization of glucose and glutamine, with enhanced glutamine-dependent lactate production, promotes cancer cell growth: The WarburQ effect

PubMed Central

Damiani, Chiara; Colombo, Riccardo; Gaglio, Daniela; Mastroianni, Fabrizia; Westerhoff, Hans Victor; Vanoni, Marco; Alberghina, Lilia

2017-01-01

Cancer cells share several metabolic traits, including aerobic production of lactate from glucose (Warburg effect), extensive glutamine utilization and impaired mitochondrial electron flow. It is still unclear how these metabolic rearrangements, which may involve different molecular events in different cells, contribute to a selective advantage for cancer cell proliferation. To ascertain which metabolic pathways are used to convert glucose and glutamine to balanced energy and biomass production, we performed systematic constraint-based simulations of a model of human central metabolism. Sampling of the feasible flux space allowed us to obtain a large number of randomly mutated cells simulated at different glutamine and glucose uptake rates. We observed that, in the limited subset of proliferating cells, most displayed fermentation of glucose to lactate in the presence of oxygen. At high utilization rates of glutamine, oxidative utilization of glucose was decreased, while the production of lactate from glutamine was enhanced. This emergent phenotype was observed only when the available carbon exceeded the amount that could be fully oxidized by the available oxygen. Under the latter conditions, standard Flux Balance Analysis indicated that: this metabolic pattern is optimal to maximize biomass and ATP production; it requires the activity of a branched TCA cycle, in which glutamine-dependent reductive carboxylation cooperates to the production of lipids and proteins; it is sustained by a variety of redox-controlled metabolic reactions. In a K-ras transformed cell line we experimentally assessed glutamine-induced metabolic changes. We validated computational results through an extension of Flux Balance Analysis that allows prediction of metabolite variations. Taken together these findings offer new understanding of the logic of the metabolic reprogramming that underlies cancer cell growth. PMID:28957320

In Situ Manufacturing of Plastics and Composites to Support H&R Exploration

NASA Astrophysics Data System (ADS)

Carranza, Susana; Makel, Darby B.; Blizman, Brandon

2006-01-01

With the new direction of NASA to emphasize the exploration of the Moon, Mars and beyond, quick development and demonstration of efficient systems for In Situ Resources Utilization (ISRU) is more critical and timely than ever before. Beyond the production of life support consumables or propellants, long term missions will require much greater levels of utilization of indigenous resources, including fabrication of habitats, radiation shielding, and replacement parts and tools. This paper reports the development of a reactor system for the synthesis of polyethylene from carbon dioxide and water. One technology commonly found in most NASA In Situ Resources Utilization scenarios is the use of the Sabatier reaction and water electrolysis to produce methane and oxygen. The system presented uses methane and oxygen to produce ethylene, and subsequently ethylene is polymerized to produce polyethylene. The process selected enables the synthesis of high-density polyethylene suitable for the fabrication of many products for space exploration, including sheets, films, channels, etc, which can be used to construct extraterrestrial habitats, tools, replacement parts, etc. Conventional fabrication processes, such as extrusion and injection molding, which are used in the fabrication of polyethylene parts, can be adapted for space operation, making polyethylene a versatile feedstock for future in-situ manufacturing plants. Studies show that polyethylene is a very good radiation shield material, making it very suitable for construction of habitats, as well as incorporation in space suits. For the fabrication of massive structures, polyethylene can be combined with indigenous soil to maximize the use of unprocessed resources, either enclosed in channels, bags, etc., or compounded in varying proportions. The focus of this paper is to present current progress in the development of manufacturing systems and processes for the production of plastics and composites utilizing indigenous resources such as planetary atmosphere and soil.

Maintaining Registered Nurses' Currency in Informatics

ERIC Educational Resources Information Center

Strawn, Jennifer Alaine

2017-01-01

Technology has changed how registered nurses (RNs) provide care at the bedside. As more technologies are utilized to improve quality of care, safety of care, maximize efficiencies, and decrease costs of care, one must question how well the information technologies (IT) are fully integrated and utilized by the front-line bedside nurse in his or her…

Network efficient power control for wireless communication systems.

PubMed

Campos-Delgado, Daniel U; Luna-Rivera, Jose Martin; Martinez-Sánchez, C J; Gutierrez, Carlos A; Tecpanecatl-Xihuitl, J L

2014-01-01

We introduce a two-loop power control that allows an efficient use of the overall power resources for commercial wireless networks based on cross-layer optimization. This approach maximizes the network's utility in the outer-loop as a function of the averaged signal to interference-plus-noise ratio (SINR) by considering adaptively the changes in the network characteristics. For this purpose, the concavity property of the utility function was verified with respect to the SINR, and an iterative search was proposed with guaranteed convergence. In addition, the outer-loop is in charge of selecting the detector that minimizes the overall power consumption (transmission and detection). Next the inner-loop implements a feedback power control in order to achieve the optimal SINR in the transmissions despite channel variations and roundtrip delays. In our proposal, the utility maximization process and detector selection and feedback power control are decoupled problems, and as a result, these strategies are implemented at two different time scales in the two-loop framework. Simulation results show that substantial utility gains may be achieved by improving the power management in the wireless network.

Network Efficient Power Control for Wireless Communication Systems

PubMed Central

Campos-Delgado, Daniel U.; Luna-Rivera, Jose Martin; Martinez-Sánchez, C. J.; Gutierrez, Carlos A.; Tecpanecatl-Xihuitl, J. L.

2014-01-01

We introduce a two-loop power control that allows an efficient use of the overall power resources for commercial wireless networks based on cross-layer optimization. This approach maximizes the network's utility in the outer-loop as a function of the averaged signal to interference-plus-noise ratio (SINR) by considering adaptively the changes in the network characteristics. For this purpose, the concavity property of the utility function was verified with respect to the SINR, and an iterative search was proposed with guaranteed convergence. In addition, the outer-loop is in charge of selecting the detector that minimizes the overall power consumption (transmission and detection). Next the inner-loop implements a feedback power control in order to achieve the optimal SINR in the transmissions despite channel variations and roundtrip delays. In our proposal, the utility maximization process and detector selection and feedback power control are decoupled problems, and as a result, these strategies are implemented at two different time scales in the two-loop framework. Simulation results show that substantial utility gains may be achieved by improving the power management in the wireless network. PMID:24683350

Optimization of Multiple Related Negotiation through Multi-Negotiation Network

NASA Astrophysics Data System (ADS)

Ren, Fenghui; Zhang, Minjie; Miao, Chunyan; Shen, Zhiqi

In this paper, a Multi-Negotiation Network (MNN) and a Multi- Negotiation Influence Diagram (MNID) are proposed to optimally handle Multiple Related Negotiations (MRN) in a multi-agent system. Most popular, state-of-the-art approaches perform MRN sequentially. However, a sequential procedure may not optimally execute MRN in terms of maximizing the global outcome, and may even lead to unnecessary losses in some situations. The motivation of this research is to use a MNN to handle MRN concurrently so as to maximize the expected utility of MRN. Firstly, both the joint success rate and the joint utility by considering all related negotiations are dynamically calculated based on a MNN. Secondly, by employing a MNID, an agent's possible decision on each related negotiation is reflected by the value of expected utility. Lastly, through comparing expected utilities between all possible policies to conduct MRN, an optimal policy is generated to optimize the global outcome of MRN. The experimental results indicate that the proposed approach can improve the global outcome of MRN in a successful end scenario, and avoid unnecessary losses in an unsuccessful end scenario.

RUSALKA

NASA Image and Video Library

2009-10-08

ISS020-E-049859 (8 Oct. 2009) --- Russian cosmonaut Maxim Suraev, Expedition 21/22 flight engineer, uses science hardware RUSALKA at a window in the Zvezda Service Module of the International Space Station to take methane and carbon dioxide measurements in Earth's atmosphere at sunset.

The effect of carbon tax on carbon emission abatement and GDP: a case study

NASA Astrophysics Data System (ADS)

Liu, Xiao; Leung, Yee; Xu, Yuan; Yung, Linda Chor Wing

2017-10-01

Carbon tax has been advocated as an effective economic instrument for the abatement of CO2 emission by various countries, including China, the world's biggest carbon emission country. However, carbon emission abatement cannot be done while ignoring the impact on economic growth. A delicate balance needs to be achieved between the two to find an appropriate pathway for sustainable development. This paper applies a multi-objective optimization approach to analyze the impact of levying carbon tax on the energy-intensive sectors of Guangdong province in China under the constraint of emission reduction target. This approach allows us to evaluate carbon emission minimization while maximizing GDP. For policy analysis, we construct five scenarios for evaluation and optimal choice. The results of the analysis show that a lower initial carbon tax rate is not necessarily better, and that a carbon tax is an effective means to reduce CO2 emissions while maintaining a certain level of GDP growth.

Utilization of Model Predictive Control to Balance Power Absorption Against Load Accumulation

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

Abbas, Nikhar; Tom, Nathan M

2017-06-03

Wave energy converter (WEC) control strategies have been primarily focused on maximizing power absorption. The use of model predictive control strategies allows for a finite-horizon, multiterm objective function to be solved. This work utilizes a multiterm objective function to maximize power absorption while minimizing the structural loads on the WEC system. Furthermore, a Kalman filter and autoregressive model were used to estimate and forecast the wave exciting force and predict the future dynamics of the WEC. The WEC's power-take-off time-averaged power and structural loads under a perfect forecast assumption in irregular waves were compared against results obtained from the Kalmanmore » filter and autoregressive model to evaluate model predictive control performance.« less

Utilization of Model Predictive Control to Balance Power Absorption Against Load Accumulation: Preprint

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

Abbas, Nikhar; Tom, Nathan

Wave energy converter (WEC) control strategies have been primarily focused on maximizing power absorption. The use of model predictive control strategies allows for a finite-horizon, multiterm objective function to be solved. This work utilizes a multiterm objective function to maximize power absorption while minimizing the structural loads on the WEC system. Furthermore, a Kalman filter and autoregressive model were used to estimate and forecast the wave exciting force and predict the future dynamics of the WEC. The WEC's power-take-off time-averaged power and structural loads under a perfect forecast assumption in irregular waves were compared against results obtained from the Kalmanmore » filter and autoregressive model to evaluate model predictive control performance.« less

Collective Intelligence. Chapter 17

NASA Technical Reports Server (NTRS)

Wolpert, David H.

2003-01-01

Many systems of self-interested agents have an associated performance criterion that rates the dynamic behavior of the overall system. This chapter presents an introduction to the science of such systems. Formally, collectives are defined as any system having the following two characteristics: First, the system must contain one or more agents each of which we view as trying to maximize an associated private utility; second, the system must have an associated world utility function that rates the possible behaviors of that overall system. In practice, collectives are often very large, distributed, and support little, if any, centralized communication and control, although those characteristics are not part of their formal definition. A naturally occurring example of a collective is a human economy. One can identify the agents and their private utilities as the human individuals in the economy and the associated personal rewards they are each trying to maximize. One could then identify the world utility as the time average of the gross domestic product. ("World utility" per se is not a construction internal to a human economy, but rather something defined from the outside.) To achieve high world utility it is necessary to avoid having the agents work at cross-purposes lest phenomena like liquidity traps or the Tragedy of the Commons (TOC) occur, in which agents' individually pursuing their private utilities lowers world utility. The obvious way to avoid such phenomena is by modifying the agents utility functions to be "aligned" with the world utility. This can be done via punitive legislation. A real-world example of an attempt to do this was the creation of antitrust regulations designed to prevent monopolistic practices.

DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

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

Larry G. Felix; P. Vann Bush

2002-10-26

This is the eighth Quarterly Technical Report for DOE Cooperative Agreement No. DE-FC26-00NT40895. A statement of the project objectives is included in the Introduction of this report. The final biomass co-firing test burn was conducted during this quarter. In this test (Test 14), up to 20% by weight dry switchgrass was comilled with Jim Walters No.7 mine coal and injected through the single-register burner. Jim Walters No.7 coal is a low-volatility, low-sulfur ({approx}0.7% S) Eastern bituminous coal. The results of this test are presented in this quarterly report. Progress has continued to be made in implementing a modeling approach tomore » combine reaction times and temperature distributions from computational fluid dynamic models of the pilot-scale combustion furnace with char burnout and chemical reaction kinetics to predict NO{sub x} emissions and unburned carbon levels in the furnace exhaust. The REI Configurable Fireside Simulator (CFS) is now in regular use. Presently, the CFS is being used to generate CFD calculations for completed tests with Powder River Basin coal and low-volatility (Jim Walters No.7 Mine) coal. Niksa Energy Associates will use the results of these CFD simulations to complete their validation of the NOx/LOI predictive model. Work has started on the project final report.« less

A strategy for low cost development of incremental oil in legacy reservoirs

USGS Publications Warehouse

Attanasi, E.D.

2016-01-01

The precipitous decline in oil prices during 2015 has forced operators to search for ways to develop low-cost and low-risk oil reserves. This study examines strategies to low cost development of legacy reservoirs, particularly those which have already implemented a carbon dioxide enhanced oil recovery (CO2 EOR) program. Initially the study examines the occurrence and nature of the distribution of the oil resources that are targets for miscible and near-miscible CO2 EOR programs. The analysis then examines determinants of technical recovery through the analysis of representative clastic and carbonate reservoirs. The economic analysis focusses on delineating the dominant components of investment and operational costs. The concluding sections describe options to maximize the value of assets that the operator of such a legacy reservoir may have that include incremental expansion within the same producing zone and to producing zones that are laterally or stratigraphically near main producing zones. The analysis identified the CO2 recycle plant as the dominant investment cost item and purchased CO2 and liquids management as a dominant operational cost items. Strategies to utilize recycle plants for processing CO2 from multiple producing zones and multiple reservoir units can significantly reduce costs. Industrial sources for CO2 should be investigated as a possibly less costly way of meeting EOR requirements. Implementation of tapered water alternating gas injection schemes can partially mitigate increases in fluid lifting costs.

Aerobic microbial mineralization of dichloroethene as sole carbon substrate

USGS Publications Warehouse

Bradley, P.M.; Chapelle, F.H.

2000-01-01

Microorganisms indigenous to the bed sediments of a black- water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.Microorganisms indigenous to the bed sediments of a black-water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.

Biofuel cell based on direct bioelectrocatalysis.

PubMed

Ramanavicius, Arunas; Kausaite, Asta; Ramanaviciene, Almira

2005-04-15

A biofuel cell, consisting of two 3mm diameter carbon rod electrodes and operating at ambient temperature in aqueous solution, pH 6, is described. Biofuel cell based on enzymes able to exchange directly electrons with carbon electrodes was constructed and characterized. Anode of the biofuel cell was based on immobilized Quino-hemoprotein alcohol dehydrogenase from Gluconobacter sp. 33 (QH-ADH), cathode on co-immobilized glucose oxidase from Aspergilus niger (GO(x)) and microperoxidase 8 from the horse heart (MP-8) acting in the consecutive mode. Two enzymes GO(x) and MP-8 applied in the design of biofuel cell cathode were acting in consecutive mode and by hydrogen peroxide oxidized MP-8 was directly accepting electrons from carbon rod electrode. If ethanol was applied as an energy source the maximal open circuit potential of the biofuel cell was -125 mV. If glucose was applied as energy source the open circuit potential of the cell was +145 mV. The maximal open circuit potential (270 mV) was achieved in the presence of extent concentration (over 2 mM) of both substrates (ethanol and glucose). Operational half-life period (tau(1/2)) of the biofuel cell was found to be 2.5 days.

Reproducibility of the exponential rise technique of CO(2) rebreathing for measuring P(v)CO(2) and C(v)CO(2 )to non-invasively estimate cardiac output during incremental, maximal treadmill exercise.

PubMed

Cade, W Todd; Nabar, Sharmila R; Keyser, Randall E

2004-05-01

The purpose of this study was to determine the reproducibility of the indirect Fick method for the measurement of mixed venous carbon dioxide partial pressure (P(v)CO(2)) and venous carbon dioxide content (C(v)CO(2)) for estimation of cardiac output (Q(c)), using the exponential rise method of carbon dioxide rebreathing, during non-steady-state treadmill exercise. Ten healthy participants (eight female and two male) performed three incremental, maximal exercise treadmill tests to exhaustion within 1 week. Non-invasive Q(c) measurements were evaluated at rest, during each 3-min stage, and at peak exercise, across three identical treadmill tests, using the exponential rise technique for measuring mixed venous PCO(2) and CCO(2) and estimating venous-arterio carbon dioxide content difference (C(v-a)CO(2)). Measurements were divided into measured or estimated variables [heart rate (HR), oxygen consumption (VO(2)), volume of expired carbon dioxide (VCO(2)), end-tidal carbon dioxide (P(ET)CO(2)), arterial carbon dioxide partial pressure (P(a)CO(2)), venous carbon dioxide partial pressure ( P(v)CO(2)), and C(v-a)CO(2)] and cardiorespiratory variables derived from the measured variables [Q(c), stroke volume (V(s)), and arteriovenous oxygen difference ( C(a-v)O(2))]. In general, the derived cardiorespiratory variables demonstrated acceptable (R=0.61) to high (R>0.80) reproducibility, especially at higher intensities and peak exercise. Measured variables, excluding P(a)CO(2) and C(v-a)CO(2), also demonstrated acceptable (R=0.6 to 0.79) to high reliability. The current study demonstrated acceptable to high reproducibility of the exponential rise indirect Fick method in measurement of mixed venous PCO(2) and CCO(2) for estimation of Q(c) during incremental treadmill exercise testing, especially at high-intensity and peak exercise.

Carbon Equivalence and Weldability of Microalloyed Steels

DTIC Science & Technology

1989-10-25

phase particles [191. The particles have been identified as retained austcnite or retained austenite- martensite . The copper precipitates ...the strengthening mc’hani;m;,, utilized in three of the four mechanisms described above do not utilize a low tcn perature phase transformation ... low carbon alloy st,-el and derives its strength from a tempered martensite structure. The set of low carbon steels include five Navy HSLA steels

Use of the hyperinsulinemic euglycemic clamp to assess insulin sensitivity in guinea pigs: dose response, partitioned glucose metabolism, and species comparisons.

PubMed

Horton, Dane M; Saint, David A; Owens, Julie A; Gatford, Kathryn L; Kind, Karen L

2017-07-01

The guinea pig is an alternate small animal model for the study of metabolism, including insulin sensitivity. However, only one study to date has reported the use of the hyperinsulinemic euglycemic clamp in anesthetized animals in this species, and the dose response has not been reported. We therefore characterized the dose-response curve for whole body glucose uptake using recombinant human insulin in the adult guinea pig. Interspecies comparisons with published data showed species differences in maximal whole body responses (guinea pig ≈ human < rat < mouse) and the insulin concentrations at which half-maximal insulin responses occurred (guinea pig > human ≈ rat > mouse). In subsequent studies, we used concomitant d-[3- 3 H]glucose infusion to characterize insulin sensitivities of whole body glucose uptake, utilization, production, storage, and glycolysis in young adult guinea pigs at human insulin doses that produced approximately half-maximal (7.5 mU·min -1 ·kg -1 ) and near-maximal whole body responses (30 mU·min -1 ·kg -1 ). Although human insulin infusion increased rates of glucose utilization (up to 68%) and storage and, at high concentrations, increased rates of glycolysis in females, glucose production was only partially suppressed (~23%), even at high insulin doses. Fasting glucose, metabolic clearance of insulin, and rates of glucose utilization, storage, and production during insulin stimulation were higher in female than in male guinea pigs ( P < 0.05), but insulin sensitivity of these and whole body glucose uptake did not differ between sexes. This study establishes a method for measuring partitioned glucose metabolism in chronically catheterized conscious guinea pigs, allowing studies of regulation of insulin sensitivity in this species. Copyright © 2017 the American Physiological Society.

Electroactive Polymeric Materials for Supercapacitors

DTIC Science & Technology

2017-06-16

composites either using transition metal oxides or different 3D carbon structures to maximize the pseudocapacitance. TECHNICAL APPROACH Our... printing /coating. Figure 9. Schematic representation of CNT forest well plate and a photograph of CNT well sample alongside a penny placed for size

An assessment of national risk: General concepts and overall approach. [carbon fiber utilization in commercial aviation

NASA Technical Reports Server (NTRS)

Kalelkar, A. S.

1979-01-01

The analysis of risk presented by carbon fiber utilization in commercial aviation is reported. The discussion is presented in three parts: (1) general concepts; (2) overall approach; and (3) risk evaluation and perspective.

Alleviation of carbon catabolite repression in Enterobacter aerogenes for efficient utilization of sugarcane molasses for 2,3-butanediol production.

PubMed

Jung, Moo-Young; Jung, Hwi-Min; Lee, Jinwon; Oh, Min-Kyu

2015-01-01

Due to its cost-effectiveness and rich sugar composition, sugarcane molasses is considered to be a promising carbon source for biorefinery. However, the sugar mixture in sugarcane molasses is not consumed as efficiently as glucose in microbial fermentation due to complex interactions among their utilizing pathways, such as carbon catabolite repression (CCR). In this study, 2,3-butanediol-producing Enterobacter aerogenes was engineered to alleviate CCR and improve sugar utilization by modulating its carbon preference. The gene encoding catabolite repressor/activator (Cra) was deleted in the genome of E. aerogenes to increase the fructose consumption rate. However, the deletion mutation repressed sucrose utilization, resulting in the accumulation of sucrose in the fermentation medium. Cra regulation on expression of the scrAB operon involved in sucrose catabolism was verified by reverse transcription and real-time PCR, and the efficiency of sucrose utilization was restored by disrupting the scrR gene and overexpressing the scrAB operon. In addition, overexpression of the ptsG gene involved in glucose utilization enhanced the glucose preference among mixed sugars, which relieved glucose accumulation in fed-batch fermentation. In fed-batch fermentation using sugarcane molasses, the maximum titer of 2,3-butanediol production by the mutant reached 140.0 g/L at 54 h, which was by far the highest titer of 2,3-butanediol with E. aerogenes achieved through genetic engineering. We have developed genetically engineered E. aerogenes as a 2,3-butanediol producer that efficiently utilizes sugarcane molasses. The fermentation efficiency was dramatically improved by the alleviation of CCR and modulation of carbon preference. These results offer a metabolic engineering approach for achieving highly efficient utilization of mixed sugars for the biorefinery industry.

Evolved hexose transporter enhances xylose uptake and glucose/xylose co-utilization in Saccharomyces cerevisiae

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

Reider Apel, Amanda; Ouellet, Mario; Szmidt-Middleton, Heather

Enhancing xylose utilization has been a major focus in Saccharomyces cerevisiae strain-engineering efforts. The incentive for these studies arises from the need to use all sugars in the typical carbon mixtures that comprise standard renewable plant-biomass-based carbon sources. While major advances have been made in developing utilization pathways, the efficient import of five carbon sugars into the cell remains an important bottleneck in this endeavor. Here we use an engineered S. cerevisiae BY4742 strain, containing an established heterologous xylose utilization pathway, and imposed a laboratory evolution regime with xylose as the sole carbon source. We obtained several evolved strains withmore » improved growth phenotypes and evaluated the best candidate using genome resequencing. We observed remarkably few single nucleotide polymorphisms in the evolved strain, among which we confirmed a single amino acid change in the hexose transporter HXT7 coding sequence to be responsible for the evolved phenotype. Lastly, the mutant HXT7(F79S) shows improved xylose uptake rates (Vmax = 186.4 ± 20.1 nmol•min -1•mg -1) that allows the S. cerevisiae strain to show significant growth with xylose as the sole carbon source, as well as partial co-utilization of glucose and xylose in a mixed sugar cultivation.« less

Evolved hexose transporter enhances xylose uptake and glucose/xylose co-utilization in Saccharomyces cerevisiae

DOE PAGES

Reider Apel, Amanda; Ouellet, Mario; Szmidt-Middleton, Heather; ...

2016-01-19

Enhancing xylose utilization has been a major focus in Saccharomyces cerevisiae strain-engineering efforts. The incentive for these studies arises from the need to use all sugars in the typical carbon mixtures that comprise standard renewable plant-biomass-based carbon sources. While major advances have been made in developing utilization pathways, the efficient import of five carbon sugars into the cell remains an important bottleneck in this endeavor. Here we use an engineered S. cerevisiae BY4742 strain, containing an established heterologous xylose utilization pathway, and imposed a laboratory evolution regime with xylose as the sole carbon source. We obtained several evolved strains withmore » improved growth phenotypes and evaluated the best candidate using genome resequencing. We observed remarkably few single nucleotide polymorphisms in the evolved strain, among which we confirmed a single amino acid change in the hexose transporter HXT7 coding sequence to be responsible for the evolved phenotype. Lastly, the mutant HXT7(F79S) shows improved xylose uptake rates (Vmax = 186.4 ± 20.1 nmol•min -1•mg -1) that allows the S. cerevisiae strain to show significant growth with xylose as the sole carbon source, as well as partial co-utilization of glucose and xylose in a mixed sugar cultivation.« less

A consistent methodology for optimal shape design of graphene sheets to maximize their fundamental frequencies considering topological defects

NASA Astrophysics Data System (ADS)

Shi, Jin-Xing; Ohmura, Keiichiro; Shimoda, Masatoshi; Lei, Xiao-Wen

2018-07-01

In recent years, shape design of graphene sheets (GSs) by introducing topological defects for enhancing their mechanical behaviors has attracted the attention of scholars. In the present work, we propose a consistent methodology for optimal shape design of GSs using a combination of the molecular mechanics (MM) method, the non-parametric shape optimization method, the phase field crystal (PFC) method, Voronoi tessellation, and molecular dynamics (MD) simulation to maximize their fundamental frequencies. At first, we model GSs as continuum frame models using a link between the MM method and continuum mechanics. Then, we carry out optimal shape design of GSs in fundamental frequency maximization problem based on a developed shape optimization method for frames. However, the obtained optimal shapes of GSs only consisting of hexagonal carbon rings are unstable that do not satisfy the principle of least action, so we relocate carbon atoms on the optimal shapes by introducing topological defects using the PFC method and Voronoi tessellation. At last, we perform the structural relaxation through MD simulation to determine the final optimal shapes of GSs. We design two examples of GSs and the optimal results show that the fundamental frequencies of GSs can be significantly enhanced according to the optimal shape design methodology.

A Joint Multitarget Estimator for the Joint Target Detection and Tracking Filter

DTIC Science & Technology

2015-06-27

function is the information theoretic part of the problem and aims for entropy maximization, while the second one arises from the constraint in the...objective functions in conflict. The first objective function is the information theo- retic part of the problem and aims for entropy maximization...theory. For the sake of completeness and clarity, we also summarize how each concept is utilized later. Entropy : A random variable is statistically

Commercial-scale utilization of greenhouse residues.

PubMed

Maroušek, Josef; Kondo, Yoshikazu; Ueno, Masami; Kawamitsu, Yoshinobu

2013-01-01

Development of techniques utilizing waste without any additional energy or rare catalysts is a starting point for becoming sustainable. In the present work, the complex utilization of greenhouse residues was studied on a commercial scale. Only the energy produced by the process (8%) was used to run the technology, thanks to multilevel heat recuperation and high methane yields (over 340 m(3) volatile solid t(-1) ). Manifestations of labile carbon in relation to available nitrogen, methane yields, and the formation of inhibitors were investigated in detail. The results sweep away many false beliefs about the ratios of carbon to nitrogen and highlight the role of the availability of carbon in phytomass utilization. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

Source-sink-storage relationships of conifers

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

Luxmoore, R.J.; Oren, R.; Sheriff, D.W.

1995-07-01

Irradiance, air temperature, saturation vapor pressure deficit, and soil temperature vary in association with Earth`s daily rotation, inducing significant hourly changes in the rates of plant physiological processes. These processes include carbon fixation in photosynthesis, sucrose translocation, and carbon utilization in growth, storage, and respiration. The sensitivity of these physiological processes to environmental factors such as temperature, soil water availability, and nutrient supply reveals differences that must be viewed as an interactive whole in order to comprehend whole-plant responses to the environment. Integrative frameworks for relationships between plant physiological processes are needed to provide syntheses of plant growth and development.more » Source-sink-storage relationships, addressed in this chapter, provide one framework for synthesis of whole-plant responses to external environmental variables. To address this issue, some examples of carbon assimilation and utilization responses of five conifer species to environmental factors from a range of field environments are first summarized. Next, the interactions between sources, sinks, and storages of carbon are examined at the leaf and tree scales, and finally, the review evaluates the proposition that processes involved with carbon utilization (sink activity) are more sensitive to the supply of water and nutrients (particularly nitrogen) than are the processes of carbon gain (source activity) and carbon storage. The terms {open_quotes}sink{close_quotes} and {open_quotes}source{close_quotes} refer to carbon utilization and carbon gain, respectively. The relative roles of stored carbon reserves and of current photosynthate in meeting sink demand are addressed. Discussions focus on source-sink-storage relationships within the diurnal, wetting-drying, and annual cycles of conifer growth and development, and some discussion of life cycle aspects is also presented.« less

Investigation of Mercury Reduction in Gold Stripping Process at Elevated Temperature

NASA Astrophysics Data System (ADS)

Pramudya, Irawan

Mercury is present in many gold ores. By processing these ores, there is a potential of emitting mercury to the environment. Carbon regeneration kiln stacks have been observed as one of the primary source of mercury emission into the atmosphere. Before it is recycled back into the carbon in leach (CIL) or carbon in columns (CIC), carbon used in the gold extraction process needs to be reactivated thermally. Emission of mercury can be minimized by keeping the mercury left in the carbon low before it goes to the carbon regeneration kiln stacks. The objective of this study is establishing the optimum elution conditions of mercury cyanide from loaded carbon (which includes the eluent, concentration, temperature and elution time) with respect to gold stripping. Several methods such as acid washing (UNR-100, HCl or ethanol/UNR-100) were investigated prior to the stripping process. Furthermore, conventional pressurized Zadra and modified Zadra were also studied with regards to mercury concentration in the solution and vapor state as well as maximizing the gold stripping from industrial loaded carbon. 7% UNR-100 acid washing of loaded carbon at 80°C was able to wash out approximately 90% of mercury while maintaining the gold adsorption on the carbon (selective washing). The addition of alcohol in the UNR-100 acid washing solution was able to enhance mercury washing from 90% to 97%. Furthermore, mercury stripping using conventional pressurized (cyanide-alkaline) Zadra was best performed at 80°C (minimal amount of mercury reduced and volatilized) whereas using the same process only 40% of gold was stripped, which makes this process not viable. When alcohol was added to the stripping solution, at 80°C, 95% of gold was detected in the solution while keeping the reduction and volatilization of mercury low. The outcome of this study provides a better understanding of mercury behavior during the acid washing and stripping processes so that the risk of mercury exposure and contamination can be minimized while maximizing the gold overall recovery.

Influencing Busy People in a Social Network

PubMed Central

Sarkar, Kaushik; Sundaram, Hari

2016-01-01

We identify influential early adopters in a social network, where individuals are resource constrained, to maximize the spread of multiple, costly behaviors. A solution to this problem is especially important for viral marketing. The problem of maximizing influence in a social network is challenging since it is computationally intractable. We make three contributions. First, we propose a new model of collective behavior that incorporates individual intent, knowledge of neighbors actions and resource constraints. Second, we show that the multiple behavior influence maximization is NP-hard. Furthermore, we show that the problem is submodular, implying the existence of a greedy solution that approximates the optimal solution to within a constant. However, since the greedy algorithm is expensive for large networks, we propose efficient heuristics to identify the influential individuals, including heuristics to assign behaviors to the different early adopters. We test our approach on synthetic and real-world topologies with excellent results. We evaluate the effectiveness under three metrics: unique number of participants, total number of active behaviors and network resource utilization. Our heuristics produce 15-51% increase in expected resource utilization over the naïve approach. PMID:27711127

Influencing Busy People in a Social Network.

PubMed

Sarkar, Kaushik; Sundaram, Hari

2016-01-01

We identify influential early adopters in a social network, where individuals are resource constrained, to maximize the spread of multiple, costly behaviors. A solution to this problem is especially important for viral marketing. The problem of maximizing influence in a social network is challenging since it is computationally intractable. We make three contributions. First, we propose a new model of collective behavior that incorporates individual intent, knowledge of neighbors actions and resource constraints. Second, we show that the multiple behavior influence maximization is NP-hard. Furthermore, we show that the problem is submodular, implying the existence of a greedy solution that approximates the optimal solution to within a constant. However, since the greedy algorithm is expensive for large networks, we propose efficient heuristics to identify the influential individuals, including heuristics to assign behaviors to the different early adopters. We test our approach on synthetic and real-world topologies with excellent results. We evaluate the effectiveness under three metrics: unique number of participants, total number of active behaviors and network resource utilization. Our heuristics produce 15-51% increase in expected resource utilization over the naïve approach.

Electromyographic and neuromuscular analysis in patients with post-polio syndrome.

PubMed

Corrêa, J C F; Rocco, C Chiusoli de Miranda; de Andrade, D Ventura; Peres, J Augusto; Corrêa, F Ishida

2008-01-01

Proceed to a comparative analysis of the electromyographic (EMG) activity of the muscles rectus femoris, vastus medialis and vastus lateralis, and to assess muscle strength and fatigue after maximal isometric contraction during knee extension. Eighteen patients with post-polio syndrome, age and weight matched, were utilized in this study. The signal acquisition system utilized consisted of three pairs of surface electrodes positioned on the motor point of the analyzed muscles. It was possible to observe with the results of this study a decreased endurance on initial muscle contraction and during contraction after 15 minutes of the initial maximal voluntary contraction, along with a muscle fatigue that was assessed through linear regression executed with Pearson's test. There were significant differences among the comparative analysis of EMG activity of the muscles rectus femoris, vastus medialis and vastus lateralis after maximal isometric contraction during knee extension. Initial muscle contraction and contraction after a 15 minute-rest from initial contraction decreased considerably, indicating a decreased endurance on muscle contraction, concluding that a lower limb muscle fatigue was present on the analyzed PPS patients.

The behavioral economics of consumer brand choice: patterns of reinforcement and utility maximization.

PubMed

Foxall, Gordon R; Oliveira-Castro, Jorge M; Schrezenmaier, Teresa C

2004-06-30

Purchasers of fast-moving consumer goods generally exhibit multi-brand choice, selecting apparently randomly among a small subset or "repertoire" of tried and trusted brands. Their behavior shows both matching and maximization, though it is not clear just what the majority of buyers are maximizing. Each brand attracts, however, a small percentage of consumers who are 100%-loyal to it during the period of observation. Some of these are exclusively buyers of premium-priced brands who are presumably maximizing informational reinforcement because their demand for the brand is relatively price-insensitive or inelastic. Others buy exclusively the cheapest brands available and can be assumed to maximize utilitarian reinforcement since their behavior is particularly price-sensitive or elastic. Between them are the majority of consumers whose multi-brand buying takes the form of selecting a mixture of economy -- and premium-priced brands. Based on the analysis of buying patterns of 80 consumers for 9 product categories, the paper examines the continuum of consumers so defined and seeks to relate their buying behavior to the question of how and what consumers maximize.

Advanced air revitalization system modeling and testing

NASA Technical Reports Server (NTRS)

Dall-Baumann, Liese; Jeng, Frank; Christian, Steve; Edeer, Marybeth; Lin, Chin

1990-01-01

To support manned lunar and Martian exploration, an extensive evaluation of air revitalization subsystems (ARS) is being conducted. The major operations under study include carbon dioxide removal and reduction; oxygen and nitrogen production, storage, and distribution; humidity and temperature control; and trace contaminant control. A comprehensive analysis program based on a generalized block flow model was developed to facilitate the evaluation of various processes and their interaction. ASPEN PLUS was used in modelling carbon dioxide removal and reduction. Several life support test stands were developed to test new and existing technologies for their potential applicability in space. The goal was to identify processes which use compact, lightweight equipment and maximize the recovery of oxygen and water. The carbon dioxide removal test stands include solid amine/vacuum desorption (SAVD), regenerative silver oxide chemisorption, and electrochemical carbon dioxide concentration (EDC). Membrane-based carbon dioxide removal and humidity control, catalytic reduction of carbon dioxide, and catalytic oxidation of trace contaminants were also investigated.

Wind farm and solar park effects on plant–soil carbon cycling: uncertain impacts of changes in ground-level microclimate

PubMed Central

Armstrong, Alona; Waldron, Susan; Whitaker, Jeanette; Ostle, Nicholas J

2014-01-01

Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land-based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground-level climate by a magnitude that could affect the fundamental plant–soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground-level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land-based renewable energy sources to alter plant–soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research. PMID:24132939

Utilization of cellulosic waste from tequila bagasse and production of polyhydroxyalkanoate (PHA) bioplastics by Saccharophagus degradans.

PubMed

Alva Munoz, Luis Esteban; Riley, Mark R

2008-08-01

Utilization of wastes from agriculture is becoming increasingly important due to concerns of environmental impact. The goals of this work were to evaluate the ability of an unusual organism, Saccharophagus degradans (ATCC 43961), to degrade the major components of plant cell walls and to evaluate the ability of S. degradans to produce polyhydroxyalkanoates (PHAs, also known as bioplastics). S. degradans can readily attach to cellulosic fibers, degrade the cellulose, and utilize this as the primary carbon source. The growth of S. degradans was assessed in minimal media (MM) containing glucose, cellobiose, avicel, and bagasse with all able to support growth. Cells were able to attach to avicel and bagasse fibers; however, growth on these insoluble fibers was much slower and led to a lower maximal biomass production than observed with simple sugars. Lignin in MM alone did not support growth, but did support growth upon addition of glucose, although with an increased adaptation phase. When culture conditions were switched to a nitrogen depleted status, PHA production commences and extends for at least 48 h. At early stationary phase, stained inclusion bodies were visible and two chronologically increasing infrared light absorbance peaks at 1,725 and 1,741 cm(-1) confirmed the presence of PHAs. This work demonstrates for what we believe to be the first time, that a single organism can degrade insoluble cellulose and under similar conditions can produce and accumulate PHA. Additional work is necessary to more fully characterize these capabilities and to optimize the PHA production and purification. (c) 2008 Wiley Periodicals, Inc.

Genomic Reconstruction of Carbohydrate Utilization Capacities in Microbial-Mat Derived Consortia

PubMed Central

Leyn, Semen A.; Maezato, Yukari; Romine, Margaret F.; Rodionov, Dmitry A.

2017-01-01

Two nearly identical unicyanobacterial consortia (UCC) were previously isolated from benthic microbial mats that occur in a heliothermal saline lake in northern Washington State. Carbohydrates are a primary source of carbon and energy for most heterotrophic bacteria. Since CO2 is the only carbon source provided, the cyanobacterium must provide a source of carbon to the heterotrophs. Available genomic sequences for all members of the UCC provide opportunity to investigate the metabolic routes of carbon transfer between autotroph and heterotrophs. Here, we applied a subsystem-based comparative genomics approach to reconstruct carbohydrate utilization pathways and identify glycohydrolytic enzymes, carbohydrate transporters and pathway-specific transcriptional regulators in 17 heterotrophic members of the UCC. The reconstructed metabolic pathways include 800 genes, near a one-fourth of which encode enzymes, transporters and regulators with newly assigned metabolic functions resulting in discovery of novel functional variants of carbohydrate utilization pathways. The in silico analysis revealed the utilization capabilities for 40 carbohydrates and their derivatives. Two Halomonas species demonstrated the largest number of sugar catabolic pathways. Trehalose, sucrose, maltose, glucose, and beta-glucosides are the most commonly utilized saccharides in this community. Reconstructed regulons for global regulators HexR and CceR include central carbohydrate metabolism genes in the members of Gammaproteobacteria and Alphaproteobacteria, respectively. Genomics analyses were supplemented by experimental characterization of metabolic phenotypes in four isolates derived from the consortia. Measurements of isolate growth on the defined medium supplied with individual carbohydrates confirmed most of the predicted catabolic phenotypes. Not all consortia members use carbohydrates and only a few use complex polysaccharides suggesting a hierarchical carbon flow from cyanobacteria to each heterotroph. In summary, the genomics-based identification of carbohydrate utilization capabilities provides a basis for future experimental studies of carbon flow in UCC. PMID:28751880

Phytoplankton division rates in light-limited environments: two adaptations

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

Rivkin, R.B.; Voytek, M.A.; Seliger, H.H.

1982-02-26

Red tide-forming dinoflagellates maximize cell numbers during periods of low light intensities in two ways. For short-term exposures to suboptimal light intensities such as might occur during recirculation in frontal convergences, cell division rates can be maintained at the expense of stored carbon for up to two generation times. During longer periods, corresponding to subsurface transport below a pycnocline, cell division rates eventually decrease as a portion of the fixed carbon is diverted to replenishing stored carbon. As a result, maximum rates of cell division can be resumed rapidly upon advection into surface waters where light intensities are optimal formore » growth.« less

Electrothermal actuation based on carbon nanotube network in silicone elastomer

NASA Astrophysics Data System (ADS)

Chen, L. Z.; Liu, C. H.; Hu, C. H.; Fan, S. S.

2008-06-01

The authors report an electrothermal actuator, which is fabricated by involving carbon nanotube network into the silicone elastomer. The actuators exhibit excellent performances as good as normal dielectric elastomer actuators while working under much lower voltages (e.g., 1.5Vmm-1). They are longitudinal actuators and there is no need for stacking or rolling sheets of materials. In addition, they can satisfy the demand of different voltage applications ranging from dozens of voltages to thousands of voltages by using different carbon nanotube loading composites. Visible maximal strain of 4.4% occurs at an electric power intensity around 0.03Wmm-3.

Optimal joint detection and estimation that maximizes ROC-type curves

PubMed Central

Wunderlich, Adam; Goossens, Bart; Abbey, Craig K.

2017-01-01

Combined detection-estimation tasks are frequently encountered in medical imaging. Optimal methods for joint detection and estimation are of interest because they provide upper bounds on observer performance, and can potentially be utilized for imaging system optimization, evaluation of observer efficiency, and development of image formation algorithms. We present a unified Bayesian framework for decision rules that maximize receiver operating characteristic (ROC)-type summary curves, including ROC, localization ROC (LROC), estimation ROC (EROC), free-response ROC (FROC), alternative free-response ROC (AFROC), and exponentially-transformed FROC (EFROC) curves, succinctly summarizing previous results. The approach relies on an interpretation of ROC-type summary curves as plots of an expected utility versus an expected disutility (or penalty) for signal-present decisions. We propose a general utility structure that is flexible enough to encompass many ROC variants and yet sufficiently constrained to allow derivation of a linear expected utility equation that is similar to that for simple binary detection. We illustrate our theory with an example comparing decision strategies for joint detection-estimation of a known signal with unknown amplitude. In addition, building on insights from our utility framework, we propose new ROC-type summary curves and associated optimal decision rules for joint detection-estimation tasks with an unknown, potentially-multiple, number of signals in each observation. PMID:27093544

Optimal Joint Detection and Estimation That Maximizes ROC-Type Curves.

PubMed

Wunderlich, Adam; Goossens, Bart; Abbey, Craig K

2016-09-01

Combined detection-estimation tasks are frequently encountered in medical imaging. Optimal methods for joint detection and estimation are of interest because they provide upper bounds on observer performance, and can potentially be utilized for imaging system optimization, evaluation of observer efficiency, and development of image formation algorithms. We present a unified Bayesian framework for decision rules that maximize receiver operating characteristic (ROC)-type summary curves, including ROC, localization ROC (LROC), estimation ROC (EROC), free-response ROC (FROC), alternative free-response ROC (AFROC), and exponentially-transformed FROC (EFROC) curves, succinctly summarizing previous results. The approach relies on an interpretation of ROC-type summary curves as plots of an expected utility versus an expected disutility (or penalty) for signal-present decisions. We propose a general utility structure that is flexible enough to encompass many ROC variants and yet sufficiently constrained to allow derivation of a linear expected utility equation that is similar to that for simple binary detection. We illustrate our theory with an example comparing decision strategies for joint detection-estimation of a known signal with unknown amplitude. In addition, building on insights from our utility framework, we propose new ROC-type summary curves and associated optimal decision rules for joint detection-estimation tasks with an unknown, potentially-multiple, number of signals in each observation.

Absence of Diauxie during Simultaneous Utilization of Glucose and Xylose by Sulfolobus acidocaldarius▿ †

PubMed Central

Joshua, Chijioke J.; Dahl, Robert; Benke, Peter I.; Keasling, Jay D.

2011-01-01

Sulfolobus acidocaldarius utilizes glucose and xylose as sole carbon sources, but its ability to metabolize these sugars simultaneously is not known. We report the absence of diauxie during growth of S. acidocaldarius on glucose and xylose as co-carbon sources. The presence of glucose did not repress xylose utilization. The organism utilized a mixture of 1 g/liter of each sugar simultaneously with a specific growth rate of 0.079 h−1 and showed no preference for the order in which it utilized each sugar. The organism grew faster on 2 g/liter xylose (0.074 h−1) as the sole carbon source than on an equal amount of glucose (0.022 h−1). When grown on a mixture of the two carbon sources, the growth rate of the organism increased from 0.052 h−1 to 0.085 h−1 as the ratio of xylose to glucose increased from 0.25 to 4. S. acidocaldarius appeared to utilize a mixture of glucose and xylose at a rate roughly proportional to their concentrations in the medium, resulting in complete utilization of both sugars at about the same time. Gene expression in cells grown on xylose alone was very similar to that in cells grown on a mixture of xylose and glucose and substantially different from that in cells grown on glucose alone. The mechanism by which the organism utilized a mixture of sugars has yet to be elucidated. PMID:21239580

Interaction and Synergism of Microbial Fuel Cell Bacteria within Methanogenesis

NASA Technical Reports Server (NTRS)

Klaus, David

2004-01-01

Biological hydrogen production from waste biomass has both terrestrial and Martian advanced life support applications. On earth, biological hydrogen production is being explored as a greenhouse neutral form of clean and efficient energy. In a permanently enclosed space habitat, carbon loop closure is required to reduce mission costs. Plants are grown to revitalize oxygen supply and are consumed by habitat inhabitants. Unharvested portions must then be recycled for reuse in the habitat. Several biological degradation techniques exist, but one process, biophotolysis, can be used to produce hydrogen from inedible plant biomass. This process is two-stage, with one stage using dark fermentation to convert plant wastes into organic acids. The second stage, photofermentation, uses photoheterotrophic purple non-sulfur bacteria with the addition of light to turn the organic acids into hydrogen and carbon dioxide. Such a system can prove useful as a co-generation scheme, providing some of the energy needed to power a larger primary carbon recovery system, such as composting. Since butyrate is expected as one of the major inputs into photofermentation, a characterization study was conducted with the bacterium Rhodobacter sphaeroides SCJ, a novel photoheterotrophic non-sulfur purple bacteria, to examine hydrogen production performance at 10 mM-100 mM butyrate concentrations. As butyrate levels increased, hydrogen production increased up to 25 mM, and then decreased and ceased by 100 mM. Additionally, lag phase increased with butyrate concentration, possibly indicating some product inhibition. Maximal substrate conversion efficiency was 8.0%; maximal light efficiency was 0.89%; and maximal hydrogen production rate was 7.7 Umol/mg/cdw/hr (173 ul/mg cdw/hr). These values were either consistent or lower than expected from literature.

Changes in soil microbial functional diversity and biochemical characteristics of tree peony with amendment of sewage sludge compost.

PubMed

Huang, Xiangdong; Xue, Dong; Xue, Lian

2015-08-01

A greenhouse experiment was conducted to investigate the impact of sewage sludge compost application on functional diversity of soil microbial communities, based on carbon source utilization, and biochemical characteristics of tree peony (Paeonia suffruticosa). Functional diversity was estimated with incubations in Biolog EcoPlates and well color development was used as the functional trait for carbon source utilization. The average well color development and Shannon index based on the carbon source utilization pattern in Biolog EcoPlates significantly increased with the increasing sludge compost application in the range of 0-45%, with a decreasing trend above 45%. Principal component analysis of carbon source utilization pattern showed that sludge compost application stimulated the utilization rate of D-cellobiose and α-D-lactose, while the utilization rate of β-methyl-D-glucoside, L-asparagine, L-serine, α-cyclodextrin, γ-hydroxybutyric acid, and itaconic acid gradually increased up to a sludge compost amendment dosage of 45% and then decreased above 45%. The chlorophyll content, antioxidase (superoxide dismutase, catalase, and peroxidase) activities, plant height, flower diameter, and flower numbers per plant of tree peony increased significantly with sludge compost dosage, reaching a peak value at 45 %, and then decreased with the exception that activity of superoxide dismutase and catalase did not vary significantly.

Measurements of carbon utilization by single bacterial species in sterile soil: insights into Rhizobium spp.

PubMed

Wigley, K; Wakelin, S A; Moot, D J; Hammond, S; Ridgway, H J

2016-08-01

The aim of this work was to develop a tool to investigate the influence of soil factors on carbon utilization activity of single micro-organisms. The assay for Rhizobium leguminosarum bv. trifolii in γ-irradiated soil, using the MicroResp(™) system, was optimized for sterility, incubation time, and moisture level. The optimized method was validated with experiments that assessed (i) differences in C utilization of different rhizobia strains and (ii) how this was affected by soil type. Carbon utilization differed among strains of the same species (and symbiovar), but some strains were more responsive to the soil environment than others. This novel modification of the MicroResp(™) has enabled the scope of carbon-utilization patterns of single strains of bacteria, such as Rh. leguminosarum bv. trifolii, to be studied in soil. The system is a new tool with applications in microbial ecology adaptable to the study of many culturable bacterial and fungal soil-borne taxa. It will allow measurement of a micro-organism's ability to utilize common C sources released in rhizosphere exudates to be measured in a physical soil background. This knowledge may improve selection efficiency and deployment of commercial microbial inoculants. © 2016 The Society for Applied Microbiology.

Land-use change in oil palm dominated tropical landscapes-An agent-based model to explore ecological and socio-economic trade-offs.

PubMed

Dislich, Claudia; Hettig, Elisabeth; Salecker, Jan; Heinonen, Johannes; Lay, Jann; Meyer, Katrin M; Wiegand, Kerstin; Tarigan, Suria

2018-01-01

Land-use changes have dramatically transformed tropical landscapes. We describe an ecological-economic land-use change model as an integrated, exploratory tool used to analyze how tropical land-use change affects ecological and socio-economic functions. The model analysis seeks to determine what kind of landscape mosaic can improve the ensemble of ecosystem functioning, biodiversity, and economic benefit based on the synergies and trade-offs that we have to account for. More specifically, (1) how do specific ecosystem functions, such as carbon storage, and economic functions, such as household consumption, relate to each other? (2) How do external factors, such as the output prices of crops, affect these relationships? (3) How do these relationships change when production inefficiency differs between smallholder farmers and learning is incorporated? We initialize the ecological-economic model with artificially generated land-use maps parameterized to our study region. The economic sub-model simulates smallholder land-use management decisions based on a profit maximization assumption. Each household determines factor inputs for all household fields and decides on land-use change based on available wealth. The ecological sub-model includes a simple account of carbon sequestration in above-ground and below-ground vegetation. We demonstrate model capabilities with results on household consumption and carbon sequestration from different output price and farming efficiency scenarios. The overall results reveal complex interactions between the economic and ecological spheres. For instance, model scenarios with heterogeneous crop-specific household productivity reveal a comparatively high inertia of land-use change. Our model analysis even shows such an increased temporal stability in landscape composition and carbon stocks of the agricultural area under dynamic price trends. These findings underline the utility of ecological-economic models, such as ours, to act as exploratory tools which can advance our understanding of the mechanisms underlying the trade-offs and synergies of ecological and economic functions in tropical landscapes.

Land-use change in oil palm dominated tropical landscapes—An agent-based model to explore ecological and socio-economic trade-offs

PubMed Central

Dislich, Claudia; Hettig, Elisabeth; Heinonen, Johannes; Lay, Jann; Meyer, Katrin M.; Wiegand, Kerstin; Tarigan, Suria

2018-01-01

Land-use changes have dramatically transformed tropical landscapes. We describe an ecological-economic land-use change model as an integrated, exploratory tool used to analyze how tropical land-use change affects ecological and socio-economic functions. The model analysis seeks to determine what kind of landscape mosaic can improve the ensemble of ecosystem functioning, biodiversity, and economic benefit based on the synergies and trade-offs that we have to account for. More specifically, (1) how do specific ecosystem functions, such as carbon storage, and economic functions, such as household consumption, relate to each other? (2) How do external factors, such as the output prices of crops, affect these relationships? (3) How do these relationships change when production inefficiency differs between smallholder farmers and learning is incorporated? We initialize the ecological-economic model with artificially generated land-use maps parameterized to our study region. The economic sub-model simulates smallholder land-use management decisions based on a profit maximization assumption. Each household determines factor inputs for all household fields and decides on land-use change based on available wealth. The ecological sub-model includes a simple account of carbon sequestration in above-ground and below-ground vegetation. We demonstrate model capabilities with results on household consumption and carbon sequestration from different output price and farming efficiency scenarios. The overall results reveal complex interactions between the economic and ecological spheres. For instance, model scenarios with heterogeneous crop-specific household productivity reveal a comparatively high inertia of land-use change. Our model analysis even shows such an increased temporal stability in landscape composition and carbon stocks of the agricultural area under dynamic price trends. These findings underline the utility of ecological-economic models, such as ours, to act as exploratory tools which can advance our understanding of the mechanisms underlying the trade-offs and synergies of ecological and economic functions in tropical landscapes. PMID:29351290

Aerobic stability of distillers’ wet grains as influenced by temperature

USDA-ARS?s Scientific Manuscript database

Maximizing the storability of distillers’ wet grains (DWG) has great influence on the economic, energetic, and carbon balances of fuel ethanol production, yet there is little published data from controlled studies on the deterioration of DWG following its production. Under laboratory conditions, we...

Li 2S encapsulated by nitrogen-doped carbon for lithium sulfur batteries

DOE PAGES

Chen, Lin; Liu, Yuzi; Ashuri, Maziar; ...

2014-09-26

Using high-energy ball milling of the Li 2S plus carbon black mixture followed by carbonization of pyrrole, we have established a facile approach to synthesize Li 2S-plus-C composite particles of average size 400 nm, encapsulated by a nitrogen-doped carbon shell. Such an engineered core–shell structure exhibits an ultrahigh initial discharge specific capacity (1029 mAh/g), reaching 88% of the theoretical capacity (1,166 mAh/g of Li 2S) and thus offering the highest utilization of Li 2S in the cathode among all of the reported works for the encapsulated Li 2S cathodes. This Li 2S/C composite core with a nitrogen-doped carbon shell canmore » still retain 652 mAh/g after prolonged 100 cycles. These superior properties are attributed to the nitrogen-doped carbon shell that can improve the conductivity to enhance the utilization of Li 2S in the cathode. As a result, fine particle sizes and the presence of carbon black within the Li 2S core may also play a role in high utilization of Li 2S in the cathode.« less

Mutations in Alternative Carbon Utilization Pathways in Candida albicans Attenuate Virulence and Confer Pleiotropic Phenotypes▿

PubMed Central

Ramírez, Melissa A.; Lorenz, Michael C.

2007-01-01

The interaction between Candida albicans and cells of the innate immune system is a key determinant of disease progression. Transcriptional profiling has revealed that C. albicans has a complex response to phagocytosis, much of which is similar to carbon starvation. This suggests that nutrient limitation is a significant stress in vivo, and we have shown that glyoxylate cycle mutants are less virulent in mice. To examine whether other aspects of carbon metabolism are important in vivo during an infection, we have constructed strains lacking FOX2 and FBP1, which encode key components of fatty acid β-oxidation and gluconeogenesis, respectively. As expected, fox2Δ mutants failed to utilize several fatty acids as carbon sources. Surprisingly, however, these mutants also failed to grow in the presence of several other carbon sources, whose assimilation is independent of β-oxidation, including ethanol and citric acid. Mutants lacking the glyoxylate enzyme ICL1 also had more severe carbon utilization phenotypes than were expected. These results suggest that the regulation of alternative carbon metabolism in C. albicans is significantly different from that in other fungi. In vivo, fox2Δ mutants show a moderate but significant reduction in virulence in a mouse model of disseminated candidiasis, while disruption of the glyoxylate cycle or gluconeogenesis confers a severe attenuation in this model. These data indicate that C. albicans often encounters carbon-poor conditions during growth in the host and that the ability to efficiently utilize multiple nonfermentable carbon sources is a virulence determinant. Consistent with this in vivo requirement, C. albicans uniquely regulates carbon metabolism in a more integrated manner than in Saccharomyces cerevisiae, such that defects in one part of the machinery have wider impacts than expected. These aspects of alternative carbon metabolism may then be useful as targets for therapeutic intervention. PMID:17158734

New insights into canted spiro carbon interstitial in graphite

NASA Astrophysics Data System (ADS)

EL-Barbary, A. A.

2017-12-01

The self-interstitial carbon is the key to radiation damage in graphite moderator nuclear reactor, so an understanding of its behavior is essential for plant safety and maximized reactor lifetime. The density functional theory is applied on four different graphite unit cells, starting from of 64 carbon atoms up to 256 carbon atoms, using AIMPRO code to obtain the energetic, athermal and mechanical properties of carbon interstitial in graphite. This study presents first principles calculations of the energy of formation that prove its high barrier to athermal diffusion (1.1 eV) and the consequent large critical shear stress (39 eV-50 eV) necessary to shear graphite planes in its presence. Also, for the first time, the gamma surface of graphite in two dimensions is calculated and found to yield the critical shear stress for perfect graphite. Finally, in contrast to the extensive literature describing the interstitial of carbon in graphite as spiro interstitial, in this work the ground state of interstitial carbon is found to be canted spiro interstitial.

Implications of net energy-return-on-investment for a low-carbon energy transition

NASA Astrophysics Data System (ADS)

King, Lewis C.; van den Bergh, Jeroen C. J. M.

2018-04-01

Low-carbon energy transitions aim to stay within a carbon budget that limits potential climate change to 2 °C—or well below—through a substantial growth in renewable energy sources alongside improved energy efficiency and carbon capture and storage. Current scenarios tend to overlook their low net energy returns compared to the existing fossil fuel infrastructure. Correcting from gross to net energy, we show that a low-carbon transition would probably lead to a 24-31% decline in net energy per capita by 2050, which implies a strong reversal of the recent rising trends of 0.5% per annum. Unless vast end-use efficiency savings can be achieved in the coming decades, current lifestyles might be impaired. To maintain the present net energy returns, solar and wind renewable power sources should grow two to three times faster than in other proposals. We suggest a new indicator, `energy return on carbon', to assist in maximizing the net energy from the remaining carbon budget.

Carbon Nanotubes versus Graphene as Flexible Transparent Electrodes in Inverted Perovskite Solar Cells.

PubMed

Jeon, Il; Yoon, Jungjin; Ahn, Namyoung; Atwa, Mohamed; Delacou, Clement; Anisimov, Anton; Kauppinen, Esko I; Choi, Mansoo; Maruyama, Shigeo; Matsuo, Yutaka

2017-11-02

Transparent carbon electrodes, carbon nanotubes, and graphene were used as the bottom electrode in flexible inverted perovskite solar cells. Their photovoltaic performance and mechanical resilience were compared and analyzed using various techniques. Whereas a conventional inverted perovskite solar cells using indium tin oxide showed a power conversion efficiency of 17.8%, the carbon nanotube- and graphene-based cells showed efficiencies of 12.8% and 14.2%, respectively. An established MoO 3 doping was used for  carbon electrode-based devices. The difference in the photovoltaic performance between the carbon nanotube- and graphene-based cells was due to the difference in morphology and transmittance. Raman spectroscopy, and cyclic flexural testing revealed that the graphene-based cells were more susceptible to strain than the carbon nanotube-based cells, though the difference was marginal. Overall, despite higher performance, the transfer step for graphene has lower reproducibility. Thus, the development of better graphene transfer methods would help maximize the current capacity of graphene-based cells.

Digital asset management.

PubMed

Humphrey, Clinton D; Tollefson, Travis T; Kriet, J David

2010-05-01

Facial plastic surgeons are accumulating massive digital image databases with the evolution of photodocumentation and widespread adoption of digital photography. Managing and maximizing the utility of these vast data repositories, or digital asset management (DAM), is a persistent challenge. Developing a DAM workflow that incorporates a file naming algorithm and metadata assignment will increase the utility of a surgeon's digital images. Copyright 2010 Elsevier Inc. All rights reserved.

Networking Micro-Processors for Effective Computer Utilization in Nursing

PubMed Central

Mangaroo, Jewellean; Smith, Bob; Glasser, Jay; Littell, Arthur; Saba, Virginia

1982-01-01

Networking as a social entity has important implications for maximizing computer resources for improved utilization in nursing. This paper describes the one process of networking of complementary resources at three institutions. Prairie View A&M University, Texas A&M University and the University of Texas School of Public Health, which has effected greater utilization of computers at the college. The results achieved in this project should have implications for nurses, users, and consumers in the development of computer resources.

Robust Coordination for Large Sets of Simple Rovers

NASA Technical Reports Server (NTRS)

Tumer, Kagan; Agogino, Adrian

2006-01-01

The ability to coordinate sets of rovers in an unknown environment is critical to the long-term success of many of NASA;s exploration missions. Such coordination policies must have the ability to adapt in unmodeled or partially modeled domains and must be robust against environmental noise and rover failures. In addition such coordination policies must accommodate a large number of rovers, without excessive and burdensome hand-tuning. In this paper we present a distributed coordination method that addresses these issues in the domain of controlling a set of simple rovers. The application of these methods allows reliable and efficient robotic exploration in dangerous, dynamic, and previously unexplored domains. Most control policies for space missions are directly programmed by engineers or created through the use of planning tools, and are appropriate for single rover missions or missions requiring the coordination of a small number of rovers. Such methods typically require significant amounts of domain knowledge, and are difficult to scale to large numbers of rovers. The method described in this article aims to address cases where a large number of rovers need to coordinate to solve a complex time dependent problem in a noisy environment. In this approach, each rover decomposes a global utility, representing the overall goal of the system, into rover-specific utilities that properly assign credit to the rover s actions. Each rover then has the responsibility to create a control policy that maximizes its own rover-specific utility. We show a method of creating rover-utilities that are "aligned" with the global utility, such that when the rovers maximize their own utility, they also maximize the global utility. In addition we show that our method creates rover-utilities that allow the rovers to create their control policies quickly and reliably. Our distributed learning method allows large sets rovers be used unmodeled domains, while providing robustness against rover failures and changing environments. In experimental simulations we show that our method scales well with large numbers of rovers in addition to being robust against noisy sensor inputs and noisy servo control. The results show that our method is able to scale to large numbers of rovers and achieves up to 400% performance improvement over standard machine learning methods.

Optimal stomatal behavior with competition for water and risk of hydraulic impairment.

PubMed

Wolf, Adam; Anderegg, William R L; Pacala, Stephen W

2016-11-15

For over 40 y the dominant theory of stomatal behavior has been that plants should open stomates until the carbon gained by an infinitesimal additional opening balances the additional water lost times a water price that is constant at least over short periods. This theory has persisted because of its remarkable success in explaining strongly supported simple empirical models of stomatal conductance, even though we have also known for over 40 y that the theory is not consistent with competition among plants for water. We develop an alternative theory in which plants maximize carbon gain without pricing water loss and also add two features to both this and the classical theory, which are strongly supported by empirical evidence: (i) water flow through xylem that is progressively impaired as xylem water potential drops and (ii) fitness or carbon costs associated with low water potentials caused by a variety of mechanisms, including xylem damage repair. We show that our alternative carbon-maximization optimization is consistent with plant competition because it yields an evolutionary stable strategy (ESS)-species with the ESS stomatal behavior that will outcompete all others. We further show that, like the classical theory, the alternative theory also explains the functional forms of empirical stomatal models. We derive ways to test between the alternative optimization criteria by introducing a metric-the marginal xylem tension efficiency, which quantifies the amount of photosynthesis a plant will forego from opening stomatal an infinitesimal amount more to avoid a drop in water potential.

Fluorination utilizing thermodynamically unstable fluorides and fluoride salts thereof

DOEpatents

Bartlett, Neil; Whalen, J. Marc; Chacon, Lisa

2000-12-12

A method for fluorinating a carbon compound or cationic carbon compound utilizes a fluorination agent selected from thermodynamically unstable nickel fluorides and salts thereof in liquid anhydrous hydrogen fluoride. The desired carbon compound or cationic organic compound to undergo fluorination is selected and reacted with the fluorination agent by contacting the selected organic or cationic organic compound and the chosen fluorination agent in a reaction vessel for a desired reaction time period at room temperature or less.

Prokaryotic silicon utilizing microorganisms in the biosphere

NASA Astrophysics Data System (ADS)

Gupta, D.; Das, S.

2012-12-01

Although a little study has been done to determine the silicon utilizing prokaryotes, our previous experiments indicated that almost all Gram-positive bacteria are silicon utilizing; one of them, Streptococci survived exposure on the lunar surface for a long period in experiment done by others. Our initial experiments with these Gram positive microorganisms showed that there were limited growths of these microorganisms on carbon free silicate medium probably with the help of some carry over carbon and nitrogen during cultivation procedures. However, increase in growth rate after repeated subcultures could not be explained at present. The main groups of prokaryotes which were found silicon utilizing microorganisms were Mycobacterium, Bacillus, Nocardia, Streptomyces, Staphylococcus, Streptococcus, Lactobacillus, and Clostridium. In a another previous study by us when silicon level was studied in such grown up cells on carbon "free" silicate medium by electron prove microanalyser, it was found that silicon in cells grown on carbon "free" silicate medium was much higher (24.9%) than those grown on conventional carbon based medium (0.84%). However, these initial findings are encouraging for our future application of this group of organisms on extraterrestrial surfaces for artificial micro-ecosystem formation. It was found that when electropositive elements are less in extraterrestrial situation, then polymerization of silicon-oxygen profusion may occur easily, particularly in carbon and nitrogen paucity in the rocky worlds of the Universe.

The Factory of the Future

NASA Technical Reports Server (NTRS)

Byman, J. E.

1985-01-01

A brief history of aircraft production techniques is given. A flexible machining cell is then described. It is a computer controlled system capable of performing 4-axis machining part cleaning, dimensional inspection and materials handling functions in an unmanned environment. The cell was designed to: allow processing of similar and dissimilar parts in random order without disrupting production; allow serial (one-shipset-at-a-time) manufacturing; reduce work-in-process inventory; maximize machine utilization through remote set-up; maximize throughput and minimize labor.

A test of ecological optimality for semiarid vegetation. M.S. Thesis

NASA Technical Reports Server (NTRS)

Salvucci, Guido D.; Eagleson, Peter S.; Turner, Edmund K.

1992-01-01

Three ecological optimality hypotheses which have utility in parameter reduction and estimation in a climate-soil-vegetation water balance model are reviewed and tested. The first hypothesis involves short term optimization of vegetative canopy density through equilibrium soil moisture maximization. The second hypothesis involves vegetation type selection again through soil moisture maximization, and the third involves soil genesis through plant induced modification of soil hydraulic properties to values which result in a maximum rate of biomass productivity.

Strategic research on the sustainable development cost of manufacturing industry under the background of carbon allowance and trade policy

NASA Astrophysics Data System (ADS)

Ma, Zhongmin; Cheng, Mengting; Wang, Mei

2017-08-01

The important subjects of energy consumption and carbon emission are manufacturing enterprises, with the deepening of international cooperation, and the implementation of carbon limit and trade policy, costs of manufacturing industry will rise sharply. How can the manufacturing industry survive in this reform, and it has to be a problem that the managers of the manufacturing industry need to solve. This paper analyses sustainable development cost connotation and value basis on the basis of sustainable development concept, discusses the influence of carbon allowance and trade policy for cost strategy of manufacturing industry, thinks that manufacturing industry should highlight social responsibility and realize maximization of social value, implement cost strategy the sustainable development, and pointed out the implementation way.

Forest canopy hydraulics

Treesearch

David R. Woodruff; Frederick C. Meinzer; Katherine A. McCulloh

2016-01-01

Water and carbon cycles are strongly coordinated and water availability is a primary limiting factor in many terrestrial ecosystems. Photosynthesis requires sufficient water supply to leaves and constraints on delivery at any point in the hydraulic continuum can lead to stomatal closure and reduced photosynthesis. Thus, maximizing water transport enhances assimilation...

Production of thermostable invertases by Aspergillus caespitosus under submerged or solid state fermentation using agroindustrial residues as carbon source

PubMed Central

Alegre, Ana Cláudia Paiva; de Lourdes Teixeira de Moraes Polizeli, Maria; Terenzi, Héctor Francisco; Jorge, João Atílio; Guimarães, Luis Henrique Souza

2009-01-01

The filamentous fungus Aspergillus caespitosus was a good producer of intracellular and extracellular invertases under submerged (SbmF) or solid-state fermentation (SSF), using agroindustrial residues, such as wheat bran, as carbon source. The production of extracellular enzyme under SSF at 30°C, for 72h, was enhanced using SR salt solution (1:1, w/v) to humidify the substrate. The extracellular activity under SSF using wheat bran was around 5.5-fold higher than that obtained in SbmF (Khanna medium) with the same carbon source. However, the production of enzyme with wheat bran plus oat meal was 2.2-fold higher than wheat bran isolated. The enzymatic production was affected by supplementation with nitrogen and phosphate sources. The addition of glucose in SbmF and SSF promoted the decreasing of extracellular activity, but the intracellular form obtained in SbmF was enhanced 3-5-fold. The invertase produced in SSF exhibited optimum temperature at 50°C while the extra- and intracellular enzymes produced in SbmF exhibited maximal activities at 60°C. All enzymatic forms exhibited maximal activities at pH 4.0-6.0 and were stable up to 1 hour at 50°C. PMID:24031406

Habitat stress initiates changes in composition, CO2 gas exchange and C-allocation as life traits in biological soil crusts.

PubMed

Colesie, Claudia; Green, T G Allan; Haferkamp, Ilka; Büdel, Burkhard

2014-10-01

Biological soil crusts (BSC) are the dominant functional vegetation unit in some of the harshest habitats in the world. We assessed BSC response to stress through changes in biotic composition, CO2 gas exchange and carbon allocation in three lichen-dominated BSC from habitats with different stress levels, two more extreme sites in Antarctica and one moderate site in Germany. Maximal net photosynthesis (NP) was identical, whereas the water content to achieve maximal NP was substantially lower in the Antarctic sites, this apparently being achieved by changes in biomass allocation. Optimal NP temperatures reflected local climate. The Antarctic BSC allocated fixed carbon (tracked using (14)CO2) mostly to the alcohol soluble pool (low-molecular weight sugars, sugar alcohols), which has an important role in desiccation and freezing resistance and antioxidant protection. In contrast, BSC at the moderate site showed greater carbon allocation into the polysaccharide pool, indicating a tendency towards growth. The results indicate that the BSC of the more stressed Antarctic sites emphasise survival rather than growth. Changes in BSC are adaptive and at multiple levels and we identify benefits and risks attached to changing life traits, as well as describing the ecophysiological mechanisms that underlie them.

Detection of glucose in the human brain with 1 H MRS at 7 Tesla.

PubMed

Kaiser, Lana G; Hirokazu, Kawaguchi; Fukunaga, Masaki; B Matson, Gerald

2016-12-01

A new method is proposed for noninvasive detection of glucose in vivo using proton MR spectroscopy at 7 Tesla. The proposed method utilizes J-difference editing to uncover the resonance of beta-glucose (β-glc) at 3.23 ppm, which is strongly overlapped with choline. Calculations using the density matrix formalism are used to maximize the signal-to-noise ratio of the β-glc resonance at 3.23 ppm. The calculations are verified using phantom and in vivo data collected at 7 Tesla. The proposed method allows observation of the glucose signal at 3.23 ppm in the human brain spectrum. Additional co-edited resonances of N-acetylaspartylglutamatate and glutathione are also detected in the same experiment. The proposed method does not require carbon ( 13 C)- labeled glucose injections and 13 C hardware; as such, it has a potential to provide valuable information on intrinsic glucose concentration in the human brain in vivo. Magn Reson Med 76:1653-1660, 2016. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Meso-pores carbon nano-tubes (CNTs) tissues-perfluorocarbons (PFCs) hybrid air-electrodes for Li-O2 battery

NASA Astrophysics Data System (ADS)

Balaish, Moran; Ein-Eli, Yair

2018-03-01

Adding immiscible perfluorocarbons (PFCs), possessing superior oxygen solubility and diffusivity, to a free-standing (metal-free and binder-free) CNTs air-electrode tissues with a meso-pore structure, fully maximized the advantages of PFCs as oxygenated-species' channels-providers. The discharge behavior of hybrid PFCs-CNT Li-O2 systems demonstrated a drastic increase in cell capacity at high current density (0.2 mA cm-2), where oxygen transport limitations are best illustrated. The results of this research revealed several key factors affecting PFCs-Li-O2 systems. The incorporation of PFCs with higher superoxide solubility and oxygen diffusivity, but more importantly higher PFCs/electrolyte miscibility, in a meso-pore air-electrode enabled better exploitation of PFCs potential. Consequently, the utilization of the air-electrode' surface area was enhanced via the formation of artificial three phase reaction zones with additional oxygen transportation routes, leading to uniform and intimate Li2O2 deposit at areas further away from the oxygen reservoir. Associated mechanisms are discussed along with insights into an improved Li-O2 battery system.

Fabrication of nanocapsule carriers from multilayer-coated vaterite calcium carbonate nanoparticles.

PubMed

Biswas, Aniket; Nagaraja, Ashvin T; McShane, Michael J

2014-12-10

Nanosized luminescent sensors were prepared as reagents for optical sensing and imaging of oxygen using ratiometric emission properties of a two-dye system. Polymeric capsules were fabricated utilizing poly(vinylsulfonic acid) (PVSA)-stabilized vaterite CaCO3 nanoparticles (CCNPs) as sacrificial templates. The buffer and polymeric surfactant requirements of the layer-by-layer (LbL) process were evaluated toward deposition of multilayer coatings and, ultimately, formation of hollow capsules using these interesting materials. CCNPs were found to be more stable in alkaline NaHCO3 buffer after repeated cycles of washing under sonication and resuspension. An intermediate PVSA concentration was required to maximize the loading of oxygen-sensitive porphyrin and oxygen-insensitive fluorescent nanoparticles in the CCNPs while maintaining minimal nanoparticle size. The CCNPs were then coated with polyelectrolyte multilayers and subsequent removal of the CaCO3 core yielded nanocapsules containing dye and fluorescent nanoparticles. The resulting nanocapsules with encapsulated luminophores functioned effectively as oxygen sensors with a quenching response of 89.28 ± 2.59%, and O2 (S = 1/2) = 20.91 μM of dissolved oxygen.

Designing Extraterrestrial Plant Growth Habitats With Low Pressure Atmospheres

NASA Technical Reports Server (NTRS)

Corey, Kenneth A.

2001-01-01

In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

Designing Extraterrestrial Plant Growth Habitats with Low Pressure Atmospheres

NASA Technical Reports Server (NTRS)

Corey, Kenneth A.

2002-01-01

In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

Electricity production from municipal solid waste using microbial fuel cells.

PubMed

Chiu, H Y; Pai, T Y; Liu, M H; Chang, C A; Lo, F C; Chang, T C; Lo, H M; Chiang, C F; Chao, K P; Lo, W Y; Lo, S W; Chu, Y L

2016-07-01

The organic content of municipal solid waste has long been an attractive source of renewable energy, mainly as a solid fuel in waste-to-energy plants. This study focuses on the potential to use microbial fuel cells to convert municipal solid waste organics into energy using various operational conditions. The results showed that two-chamber microbial fuel cells with carbon felt and carbon felt allocation had a higher maximal power density (20.12 and 30.47 mW m(-2) for 1.5 and 4 L, respectively) than those of other electrode plate allocations. Most two-chamber microbial fuel cells (1.5 and 4 L) had a higher maximal power density than single-chamber ones with corresponding electrode plate allocations. Municipal solid waste with alkali hydrolysis pre-treatment and K3Fe(CN)6 as an electron acceptor improved the maximal power density to 1817.88 mW m(-2) (~0.49% coulomb efficiency, from 0.05-0.49%). The maximal power density from experiments using individual 1.5 and 4 L two-chamber microbial fuel cells, and serial and parallel connections of 1.5 and 4 L two-chamber microbial fuel cells, was found to be in the order of individual 4 L (30.47 mW m(-2)) > serial connection of 1.5 and 4 L (27.75) > individual 1.5 L (20.12) > parallel connection of 1.5 and 4 L (17.04) two-chamber microbial fuel cells . The power density using municipal solid waste microbial fuel cells was compared with information in the literature and discussed. © The Author(s) 2016.

Energy efficiency in the U.S. residential sector: An engineering and economic assessment of opportunities for large energy savings and greenhouse gas emissions reductions

NASA Astrophysics Data System (ADS)

Lima de Azevedo, Ines Margarida

Energy efficiency and conservation is a very promising part of a portfolio of the needed strategies to mitigate climate change. Several technologies and energy efficiency measures in the residential sector offer potential for large energy savings. However, while energy efficiency options are currently considered as a means of reducing carbon emissions, there is still large uncertainty about the effect of such measures on overall carbon savings. The first part of this thesis provides a national assessment of the energy efficiency potential in the residential sector under several different scenarios, which include the perspectives of different economic agents (consumers, utilities, ESCOs, and a society). The scenarios also include maximizing energy, electricity or carbon dioxide savings. The second part of this thesis deals with a detailed assessment of the potential for white-light LEDs for energy and carbon dioxide savings in the U.S. commercial and residential sectors. Solid-state lighting shows great promise as a source of efficient, affordable, color-balanced white light. Indeed, assuming market discount rates, the present work demonstrates that white solid-state lighting already has a lower levelized annual cost (LAC) than incandescent bulbs and that it will be lower than that of the most efficient fluorescent bulbs by the end of this decade. However, a large literature indicates that households do not make their decisions in terms of simple expected economic value. The present analysis shows that incorporating the findings from literature on high implicit discount rates from households when performing decisions towards efficient technologies delays the adoption of white LEDs by a couple of years. After a review of the technology, the present work compares the electricity consumption, carbon emissions and cost-effectiveness of current lighting technologies, when accounting for expected performance evolution through 2015. Simulations of lighting electricity consumption and implicit greenhouse gases emissions for the U.S. residential and commercial sectors through 2015 under different policy scenarios (voluntary solid-state lighting adoption, implementation of lighting standards in new construction and rebate programs or equivalent subsidies) are also included.

Improvement of L-phenylalanine production from glycerol by recombinant Escherichia coli strains: The role of extra copies of glpK, glpX, and tktA genes

PubMed Central

2014-01-01

Background For the production of L-phenylalanine (L-Phe), two molecules of phosphoenolpyruvate (PEP) and one molecule erythrose-4-phosphate (E4P) are necessary. PEP stems from glycolysis whereas E4P is formed in the pentose phosphate pathway (PPP). Glucose, commonly used for L-Phe production with recombinant E. coli, is taken up via the PEP-dependent phosphotransferase system which delivers glucose-6-phosphate (G6P). G6P enters either glycolysis or the PPP. In contrast, glycerol is phosphorylated by an ATP-dependent glycerol kinase (GlpK) thus saving one PEP. However, two gluconeogenic reactions (fructose-1,6-bisphosphate aldolase, fructose-1,6-bisphosphatase, FBPase) are necessary for growth and provision of E4P. Glycerol has become an important carbon source for biotechnology and reports on production of L-Phe from glycerol are available. However, the influence of FBPase and transketolase reactions on L-Phe production has not been reported. Results L-Phe productivity of parent strain FUS4/pF81 (plasmid-encoded genes for aroF, aroB, aroL, pheA) was compared on glucose and glycerol as C sources. On glucose, a maximal carbon recovery of 0.19 mM CPhe/CGlucose and a maximal space-time-yield (STY) of 0.13 g l−1 h−1 was found. With glycerol, the maximal carbon recovery was nearly the same (0.18 mM CPhe/CGlycerol), but the maximal STY was higher (0.21 g l−1 h−1). We raised the chromosomal gene copy number of the genes glpK (encoding glycerol kinase), tktA (encoding transketolase), and glpX (encoding fructose-1,6-bisphosphatase) individually. Overexpression of glpK (or its feedback-resistant variant, glpKG232D) had little effect on growth rate; L-Phe production was about 30% lower than in FUS4/pF81. Whereas the overexpression of either glpX or tktA had minor effects on productivity (0.20 mM CPhe/CGlycerol; 0.25 g l−1 h−1 and 0.21 mM CPhe/CGlycerol; 0.23 g l−1 h−1, respectively), the combination of extra genes of glpX and tktA together led to an increase in maximal STY of about 80% (0.37 g l−1 h−1) and a carbon recovery of 0.26 mM CPhe/CGlycerol. Conclusions Enhancing the gene copy numbers for glpX and tktA increased L-Phe productivity from glycerol without affecting growth rate. Engineering of glycerol metabolism towards L-Phe production in E. coli has to balance the pathways of gluconeogenesis, glycolysis, and PPP to improve the supply of the precursors, PEP and E4P. PMID:25012491

Improvement of L-phenylalanine production from glycerol by recombinant Escherichia coli strains: the role of extra copies of glpK, glpX, and tktA genes.

PubMed

Gottlieb, Katrin; Albermann, Christoph; Sprenger, Georg A

2014-07-11

For the production of L-phenylalanine (L-Phe), two molecules of phosphoenolpyruvate (PEP) and one molecule erythrose-4-phosphate (E4P) are necessary. PEP stems from glycolysis whereas E4P is formed in the pentose phosphate pathway (PPP). Glucose, commonly used for L-Phe production with recombinant E. coli, is taken up via the PEP-dependent phosphotransferase system which delivers glucose-6-phosphate (G6P). G6P enters either glycolysis or the PPP. In contrast, glycerol is phosphorylated by an ATP-dependent glycerol kinase (GlpK) thus saving one PEP. However, two gluconeogenic reactions (fructose-1,6-bisphosphate aldolase, fructose-1,6-bisphosphatase, FBPase) are necessary for growth and provision of E4P. Glycerol has become an important carbon source for biotechnology and reports on production of L-Phe from glycerol are available. However, the influence of FBPase and transketolase reactions on L-Phe production has not been reported. L-Phe productivity of parent strain FUS4/pF81 (plasmid-encoded genes for aroF, aroB, aroL, pheA) was compared on glucose and glycerol as C sources. On glucose, a maximal carbon recovery of 0.19 mM C(Phe)/C(Glucose) and a maximal space-time-yield (STY) of 0.13 g l(-1) h(-1) was found. With glycerol, the maximal carbon recovery was nearly the same (0.18 mM C(Phe)/C(Glycerol)), but the maximal STY was higher (0.21 g l(-1) h(-1)). We raised the chromosomal gene copy number of the genes glpK (encoding glycerol kinase), tktA (encoding transketolase), and glpX (encoding fructose-1,6-bisphosphatase) individually. Overexpression of glpK (or its feedback-resistant variant, glpK(G232D)) had little effect on growth rate; L-Phe production was about 30% lower than in FUS4/pF81. Whereas the overexpression of either glpX or tktA had minor effects on productivity (0.20 mM C(Phe)/C(Glycerol); 0.25 g l(-1) h(-1) and 0.21 mM C(Phe)/C(Glycerol); 0.23 g l(-1) h(-1), respectively), the combination of extra genes of glpX and tktA together led to an increase in maximal STY of about 80% (0.37 g l(-1) h(-1)) and a carbon recovery of 0.26 mM C(Phe)/C(Glycerol). Enhancing the gene copy numbers for glpX and tktA increased L-Phe productivity from glycerol without affecting growth rate. Engineering of glycerol metabolism towards L-Phe production in E. coli has to balance the pathways of gluconeogenesis, glycolysis, and PPP to improve the supply of the precursors, PEP and E4P.

How should leaf area, sapwood area and stomatal conductance vary with tree height to maximize growth?

PubMed

Buckley, Thomas N; Roberts, David W

2006-02-01

Conventional wisdom holds that the ratio of leaf area to sapwood area (L/S) should decline during height (H) growth to maintain hydraulic homeostasis and prevent stomatal conductance (g(s)) from declining. We contend that L/S should increase with H based on a numerical simulation, a mathematical analysis and a conceptual argument: (1) numerical simulation--a tree growth model, DESPOT (Deducing Emergent Structure and Physiology Of Trees), in which carbon (C) allocation is regulated to maximize C gain, predicts L/S should increase during most of H growth; (2) mathematical analysis--the formal criterion for optimal C allocation, applied to a simplified analytical model of whole tree carbon-water balance, predicts L/S should increase with H if leaf-level gas exchange parameters including g(s) are conserved; and (3) conceptual argument--photosynthesis is limited by several substitutable resources (chiefly nitrogen (N), water and light) and H growth increases the C cost of water transport but not necessarily of N and light capture, so if the goal is to maximize C gain or growth, allocation should shift in favor of increasing photosynthetic capacity and irradiance, rather than sustaining g(s). Although many data are consistent with the prediction that L/S should decline with H, many others are not, and we discuss possible reasons for these discrepancies.

Utilization of ancient permafrost carbon in headwaters of Arctic fluvial networks.

PubMed

Mann, Paul J; Eglinton, Timothy I; McIntyre, Cameron P; Zimov, Nikita; Davydova, Anna; Vonk, Jorien E; Holmes, Robert M; Spencer, Robert G M

2015-07-24

Northern high-latitude rivers are major conduits of carbon from land to coastal seas and the Arctic Ocean. Arctic warming is promoting terrestrial permafrost thaw and shifting hydrologic flowpaths, leading to fluvial mobilization of ancient carbon stores. Here we describe (14)C and (13)C characteristics of dissolved organic carbon from fluvial networks across the Kolyma River Basin (Siberia), and isotopic changes during bioincubation experiments. Microbial communities utilized ancient carbon (11,300 to >50,000 (14)C years) in permafrost thaw waters and millennial-aged carbon (up to 10,000 (14)C years) across headwater streams. Microbial demand was supported by progressively younger ((14)C-enriched) carbon downstream through the network, with predominantly modern carbon pools subsidizing microorganisms in large rivers and main-stem waters. Permafrost acts as a significant and preferentially degradable source of bioavailable carbon in Arctic freshwaters, which is likely to increase as permafrost thaw intensifies causing positive climate feedbacks in response to on-going climate change.

77 FR 25145 - Commerce Spectrum Management Advisory Committee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-27

... innovation as possible, and make wireless services available to all Americans. (See charter, at http://www... federal capabilities and maximizing commercial utilization. NTIA will post a detailed agenda on its Web...

Retrieval of cloud cover parameters from multispectral satellite images

NASA Technical Reports Server (NTRS)

Arking, A.; Childs, J. D.

1985-01-01

A technique is described for extracting cloud cover parameters from multispectral satellite radiometric measurements. Utilizing three channels from the AVHRR (Advanced Very High Resolution Radiometer) on NOAA polar orbiting satellites, it is shown that one can retrieve four parameters for each pixel: cloud fraction within the FOV, optical thickness, cloud-top temperature and a microphysical model parameter. The last parameter is an index representing the properties of the cloud particle and is determined primarily by the radiance at 3.7 microns. The other three parameters are extracted from the visible and 11 micron infrared radiances, utilizing the information contained in the two-dimensional scatter plot of the measured radiances. The solution is essentially one in which the distributions of optical thickness and cloud-top temperature are maximally clustered for each region, with cloud fraction for each pixel adjusted to achieve maximal clustering.

Optimal population size and endogenous growth.

PubMed

Palivos, T; Yip, C K

1993-01-01

"Many applications in economics require the selection of an objective function which enables the comparison of allocations involving different population sizes. The two most commonly used criteria are the Benthamite and the Millian welfare functions, also known as classical and average utilitarianism, respectively. The former maximizes total utility of the society and thus represents individuals, while the latter maximizes average utility and so represents generations. Edgeworth (1925) was the first to conjecture, that the Benthamite principle leads to a larger population size and a lower standard of living.... The purpose of this paper is to examine Edgeworth's conjecture in an endogenous growth framework in which there are interactions between output and population growth rates. It is shown that, under conditions that ensure an optimum, the Benthamite criterion leads to smaller population and higher output growth rates than the Millian." excerpt

A Quantitative Three-Dimensional Image Analysis Tool for Maximal Acquisition of Spatial Heterogeneity Data.

PubMed

Allenby, Mark C; Misener, Ruth; Panoskaltsis, Nicki; Mantalaris, Athanasios

2017-02-01

Three-dimensional (3D) imaging techniques provide spatial insight into environmental and cellular interactions and are implemented in various fields, including tissue engineering, but have been restricted by limited quantification tools that misrepresent or underutilize the cellular phenomena captured. This study develops image postprocessing algorithms pairing complex Euclidean metrics with Monte Carlo simulations to quantitatively assess cell and microenvironment spatial distributions while utilizing, for the first time, the entire 3D image captured. Although current methods only analyze a central fraction of presented confocal microscopy images, the proposed algorithms can utilize 210% more cells to calculate 3D spatial distributions that can span a 23-fold longer distance. These algorithms seek to leverage the high sample cost of 3D tissue imaging techniques by extracting maximal quantitative data throughout the captured image.

Maintaining homeostasis by decision-making.

PubMed

Korn, Christoph W; Bach, Dominik R

2015-05-01

Living organisms need to maintain energetic homeostasis. For many species, this implies taking actions with delayed consequences. For example, humans may have to decide between foraging for high-calorie but hard-to-get, and low-calorie but easy-to-get food, under threat of starvation. Homeostatic principles prescribe decisions that maximize the probability of sustaining appropriate energy levels across the entire foraging trajectory. Here, predictions from biological principles contrast with predictions from economic decision-making models based on maximizing the utility of the endpoint outcome of a choice. To empirically arbitrate between the predictions of biological and economic models for individual human decision-making, we devised a virtual foraging task in which players chose repeatedly between two foraging environments, lost energy by the passage of time, and gained energy probabilistically according to the statistics of the environment they chose. Reaching zero energy was framed as starvation. We used the mathematics of random walks to derive endpoint outcome distributions of the choices. This also furnished equivalent lotteries, presented in a purely economic, casino-like frame, in which starvation corresponded to winning nothing. Bayesian model comparison showed that--in both the foraging and the casino frames--participants' choices depended jointly on the probability of starvation and the expected endpoint value of the outcome, but could not be explained by economic models based on combinations of statistical moments or on rank-dependent utility. This implies that under precisely defined constraints biological principles are better suited to explain human decision-making than economic models based on endpoint utility maximization.

Maintaining Homeostasis by Decision-Making

PubMed Central

Korn, Christoph W.; Bach, Dominik R.

2015-01-01

Living organisms need to maintain energetic homeostasis. For many species, this implies taking actions with delayed consequences. For example, humans may have to decide between foraging for high-calorie but hard-to-get, and low-calorie but easy-to-get food, under threat of starvation. Homeostatic principles prescribe decisions that maximize the probability of sustaining appropriate energy levels across the entire foraging trajectory. Here, predictions from biological principles contrast with predictions from economic decision-making models based on maximizing the utility of the endpoint outcome of a choice. To empirically arbitrate between the predictions of biological and economic models for individual human decision-making, we devised a virtual foraging task in which players chose repeatedly between two foraging environments, lost energy by the passage of time, and gained energy probabilistically according to the statistics of the environment they chose. Reaching zero energy was framed as starvation. We used the mathematics of random walks to derive endpoint outcome distributions of the choices. This also furnished equivalent lotteries, presented in a purely economic, casino-like frame, in which starvation corresponded to winning nothing. Bayesian model comparison showed that—in both the foraging and the casino frames—participants’ choices depended jointly on the probability of starvation and the expected endpoint value of the outcome, but could not be explained by economic models based on combinations of statistical moments or on rank-dependent utility. This implies that under precisely defined constraints biological principles are better suited to explain human decision-making than economic models based on endpoint utility maximization. PMID:26024504

Seeing the forest beyond the carbon

NASA Astrophysics Data System (ADS)

Schwalm, C.; Giffen, A.; Duffy, P.; Houghton, R. A.; Lowenstein, F.; Perschel, R.; Rogers, B. M.

2016-12-01

Climate policy should be about more than obviating greenhouse gas emissions from fossil fuel combustion. From Kyoto onward forests and forest management have played a role-albeit a misspecified one-in climate policy. The 2015 COP21 Paris Agreement took the unprecedented step of providing funding for REDD+; re-emphasizing the importance of forest stewardship as a policy vehicle. This step is welcome but still falls well short of leveraging the full effect of forests on climate in the context of policy. Forest-climate effects can be grouped in three broad categories: (1) land carbon sink, i.e., maximizing carbon contained in forest carbon stocks; (2) biophysical effects whereby forest structure and extent influence climate directly; and (3) the use of wood in long-lived structures, i.e., "build it with wood". This last category refers to offsetting fossil fuel emissions through forest management and the use of wood products. Climate policy strongly emphasizes the land carbon sink. This ignores management as a means to alter climate-through, for example, evaporative cooling, cloud engineering, and the albedo effect-as well as the up to 31% decrease in CO2 emissions if wood were substituted for other construction materials. We present a new framework for forest-based climate policy that accounts for all three types for forest-climate effects. A clear change in course is needed. This agenda-for-change must move toward policy and subsidy that foster forest management and use that (1) minimizes total CO2 emissions, (2) maximizes biophysical climate benefits, and (3) provides communities with still greater incentives to maintain forest cover and quality. Absent such incentives we are left with the prospect that we are not harnessing the full potential of forests in climate regulation. Indeed, we may be making our climate situation worse.

Utilizing Diffusion Theory to predict carbon dioxide concentration in an indoor environment

NASA Astrophysics Data System (ADS)

Kramer, Andrew R.

This research details a new method of relating sources of carbon dioxide to carbon dioxide concentration in a room operating in a reduced ventilation mode by utilizing Diffusion Theory. The theoretical basis of this research involved solving Fick's Second Law of Diffusion in spherical coordinates for a source of carbon dioxide flowing at a constant rate and located in the center of an impermeable spherical boundary. The solution was developed using a Laplace Transformation. A spherical diffusion test chamber was constructed and used to validate and benchmark the developed theory. The method was benchmarked by using Dispersion Coefficients for large carbon dioxide flow rates due to diffusion induced convection. The theoretical model was adapted to model a room operating with restricted ventilation in the presence of a known, constant source of carbon dioxide. The room was modeled as a sphere of volume equal to the room and utilized a Dispersion Coefficient that is consistent with published values. The developed Diffusion Model successfully predicted the spatial concentration of carbon dioxide in a room operating in a reduced ventilation mode in the presence of a source of carbon dioxide. The flow rates of carbon dioxide that were used in the room are comparable to the average flow rate of carbon dioxide from a person during quiet breathing, also known as the Tidal Breathing. This indicates the Diffusion Model developed from this research has the potential to correlate carbon dioxide concentration with static occupancy levels which can lead to energy savings through a reduction in air exchange rates when low occupancy is detected.

Development of a semigraphitic sulfur-doped ordered mesoporous carbon material for electroanalytical applications

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

Maluta, Jaqueline R.; Machado, Sergio A. S.; Chaudhary, Umesh

The modification of traditional electrodes with mesoporous carbons is a promising strategy to produce high performance electrodes for electrochemical sensing. The high surface area of mesoporous carbons provides a large number of electroactive sites for binding analytes. Controlling the pore size and structure of mesoporous carbons and modifying their electronic properties via doping offers additional benefits like maximizing transport and tuning the electrochemical processes associated with analyte detection. This work reports a facile method to produce sulfur-doped ordered mesoporous carbon materials (S-OMC) with uniform pore structure, large pore volume, high surface area and semigraphitic structure. The synthesis used thiophenol asmore » a single source of carbon and sulfur, and iron as a catalyst for low temperature carbonization. The S-OMC material was deposited on a glassy carbon electrode and used as a sensor with high sensitivity (11.7 A L mol-1) and selectivity for chloramphenicol detection in presence of other antibiotics. As a proof-of-concept, the sensor was applied to the direct analysis of the drug in reconstituted powdered milk and in commercial eye drops.« less

Development of a semigraphitic sulfur-doped ordered mesoporous carbon material for electroanalytical applications

DOE PAGES

Maluta, Jaqueline R.; Machado, Sergio A. S.; Chaudhary, Umesh; ...

2017-10-29

The modification of traditional electrodes with mesoporous carbons is a promising strategy to produce high performance electrodes for electrochemical sensing. The high surface area of mesoporous carbons provides a large number of electroactive sites for binding analytes. Controlling the pore size and structure of mesoporous carbons and modifying their electronic properties via doping offers additional benefits like maximizing transport and tuning the electrochemical processes associated with analyte detection. This work reports a facile method to produce sulfur-doped ordered mesoporous carbon materials (S-OMC) with uniform pore structure, large pore volume, high surface area and semigraphitic structure. The synthesis used thiophenol asmore » a single source of carbon and sulfur, and iron as a catalyst for low temperature carbonization. The S-OMC material was deposited on a glassy carbon electrode and used as a sensor with high sensitivity (11.7 A L mol-1) and selectivity for chloramphenicol detection in presence of other antibiotics. As a proof-of-concept, the sensor was applied to the direct analysis of the drug in reconstituted powdered milk and in commercial eye drops.« less

Short- and long-term effects of fire on carbon in US dry temperate forest systems

USGS Publications Warehouse

Hurteau, Matthew D.; Brooks, Matthew L.

2011-01-01

Forests sequester carbon from the atmosphere, and in so doing can mitigate the effects of climate change. Fire is a natural disturbance process in many forest systems that releases carbon back to the atmosphere. In dry temperate forests, fires historically burned with greater frequency and lower severity than they do today. Frequent fires consumed fuels on the forest floor and maintained open stand structures. Fire suppression has resulted in increased understory fuel loads and tree density; a change in structure that has caused a shift from low- to high-severity fires. More severe fires, resulting in greater tree mortality, have caused a decrease in forest carbon stability. Fire management actions can mitigate the risk of high-severity fires, but these actions often require a trade-off between maximizing carbon stocks and carbon stability. We discuss the effects of fire on forest carbon stocks and recommend that managing forests on the basis of their specific ecologies should be the foremost goal, with carbon sequestration being an ancillary benefit. ?? 2011 by American Institute of Biological Sciences. All rights reserved.

Hypoglycemic depression of RES function.

PubMed

Buchanan, B J; Filkins, J P

1976-07-01

The intravascular removal rates of colloidal carbon and of biologically active endotoxin by the reticuloendothelial system (RES) were evaluated as a function of blood-glucose levels. There was a significant negative correlation of carbon clearance half time on blood glucose in both saline-treated and insulin-treated rats. Insulin hypoglycemia depressed RES carbon clearance with the maximal effect occurring at blood glucose values below 30 mg/dl. Insulin hypoglycemia also severely impaired the intravascular removal of endotoxin as evaluated by lethality bioassay in lead-sensitized rats. It is concluded that blood glucose may modulate RES phagocytic function and that the hypoglycemia of endotoxin shock may augment the shock state due to impairment of RES host defense clearance functions.

Long-Term Counterinsurgency Strategy: Maximizing Special Operations and Airpower

DTIC Science & Technology

2010-02-01

operations forces possess a repertoire of capabilities and attributes which impart them with unique strategic utility. “That utility reposes most...flashlight), LTMs are employed in a similar role to cue aircrews equipped with Night Vision Devices (NVDs). Concurrently, employment of small laptop...Special Operations Forces (PSS-SOF) and Precision Fires Image Generator (PFIG) have brought similar benefit to the employment of GPS/INS targeted weapons

Decision Making Analysis: Critical Factors-Based Methodology

DTIC Science & Technology

2010-04-01

the pitfalls associated with current wargaming methods such as assuming a western view of rational values in decision - making regardless of the cultures...Utilization theory slightly expands the rational decision making model as it states that “actors try to maximize their expected utility by weighing the...items to categorize the decision - making behavior of political leaders which tend to demonstrate either a rational or cognitive leaning. Leaders

Breath carbon stable isotope ratios identify changes in energy balance and substrate utilization in humans

USDA-ARS?s Scientific Manuscript database

Rapid detection of shifts in substrate utilization and energy balance would provide a compelling biofeedback tool to enable individuals to lose weight. In a pilot study, we tested whether the natural abundance of exhaled carbon stable isotope ratios (breath d13C values) reflects shifts between negat...

Establishing a synergetic carbon utilization mechanism for non-catabolic use of glucose in microbial synthesis of trehalose.

PubMed

Wu, Yifei; Sun, Xinxiao; Lin, Yuheng; Shen, Xiaolin; Yang, Yaping; Jain, Rachit; Yuan, Qipeng; Yan, Yajun

2017-01-01

In nature glucose is a common carbon and energy source for catabolic use and also a building unit of polysaccharides and glycosylated compounds. The presence of strong glucose catabolic pathways in microorganism rapidly decomposes glucose into smaller metabolites and challenges non-catabolic utilization of glucose as C6 building unit or precursor. To address this dilemma, we design a synergetic carbon utilization mechanism (SynCar), in which glucose catabolism is inactivated and a second carbon source (e.g. glycerol) is employed to maintain cell growth and rationally strengthen PEP driving force for glucose uptake and non-catabolic utilization. Remarkably, a trehalose biosynthesis model developed for proof-of-concept indicates that SynCar leads to 131% and 200% improvement in trehalose titer and yield, respectively. The conversion rate of glucose to trehalose reaches 91% of the theoretical maximum. This work demonstrates the broad applicability of SynCar in the biosynthesis of molecules derived from non-catabolic glucose. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

On Social Optima of Non-Cooperative Mean Field Games

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

Li, Sen; Zhang, Wei; Zhao, Lin

This paper studies the social optima in noncooperative mean-field games for a large population of agents with heterogeneous stochastic dynamic systems. Each agent seeks to maximize an individual utility functional, and utility functionals of different agents are coupled through a mean field term that depends on the mean of the population states/controls. The paper has the following contributions. First, we derive a set of control strategies for the agents that possess *-Nash equilibrium property, and converge to the mean-field Nash equilibrium as the population size goes to infinity. Second, we study the social optimal in the mean field game. Wemore » derive the conditions, termed the socially optimal conditions, under which the *-Nash equilibrium of the mean field game maximizes the social welfare. Third, a primal-dual algorithm is proposed to compute the *-Nash equilibrium of the mean field game. Since the *-Nash equilibrium of the mean field game is socially optimal, we can compute the equilibrium by solving the social welfare maximization problem, which can be addressed by a decentralized primal-dual algorithm. Numerical simulations are presented to demonstrate the effectiveness of the proposed approach.« less

Research priorities and plans for the International Space Station-results of the 'REMAP' Task Force

NASA Technical Reports Server (NTRS)

Kicza, M.; Erickson, K.; Trinh, E.

2003-01-01

Recent events in the International Space Station (ISS) Program have resulted in the necessity to re-examine the research priorities and research plans for future years. Due to both technical and fiscal resource constraints expected on the International Space Station, it is imperative that research priorities be carefully reviewed and clearly articulated. In consultation with OSTP and the Office of Management and budget (OMB), NASA's Office of Biological and Physical Research (OBPR) assembled an ad-hoc external advisory committee, the Biological and Physical Research Maximization and Prioritization (REMAP) Task Force. This paper describes the outcome of the Task Force and how it is being used to define a roadmap for near and long-term Biological and Physical Research objectives that supports NASA's Vision and Mission. Additionally, the paper discusses further prioritizations that were necessitated by budget and ISS resource constraints in order to maximize utilization of the International Space Station. Finally, a process has been developed to integrate the requirements for this prioritized research with other agency requirements to develop an integrated ISS assembly and utilization plan that maximizes scientific output. c2003 American Institute of Aeronautics and Astronautics. Published by Elsevier Science Ltd. All rights reserved.

A framework for optimization and quantification of uncertainty and sensitivity for developing carbon capture systems

DOE PAGES

Eslick, John C.; Ng, Brenda; Gao, Qianwen; ...

2014-12-31

Under the auspices of the U.S. Department of Energy’s Carbon Capture Simulation Initiative (CCSI), a Framework for Optimization and Quantification of Uncertainty and Sensitivity (FOQUS) has been developed. This tool enables carbon capture systems to be rapidly synthesized and rigorously optimized, in an environment that accounts for and propagates uncertainties in parameters and models. FOQUS currently enables (1) the development of surrogate algebraic models utilizing the ALAMO algorithm, which can be used for superstructure optimization to identify optimal process configurations, (2) simulation-based optimization utilizing derivative free optimization (DFO) algorithms with detailed black-box process models, and (3) rigorous uncertainty quantification throughmore » PSUADE. FOQUS utilizes another CCSI technology, the Turbine Science Gateway, to manage the thousands of simulated runs necessary for optimization and UQ. Thus, this computational framework has been demonstrated for the design and analysis of a solid sorbent based carbon capture system.« less

Active pore space utilization in nanoporous carbon-based supercapacitors: Effects of conductivity and pore accessibility

NASA Astrophysics Data System (ADS)

Seredych, Mykola; Koscinski, Mikolaj; Sliwinska-Bartkowiak, Malgorzata; Bandosz, Teresa J.

2012-12-01

Composites of commercial graphene and nanoporous sodium-salt-polymer-derived carbons were prepared with 5 or 20 weight% graphene. The materials were characterized using the adsorption of nitrogen, SEM/EDX, thermal analysis, Raman spectroscopy and potentiometric titration. The samples' conductivity was also measured. The performance of the carbon composites in energy storage was linked to their porosity and electronic conductivity. The small pores (<0.7) were found as very active for double layer capacitance. It was demonstrated that when double layer capacitance is a predominant mechanism of charge storage, the degree of the pore space utilization for that storage can be increased by increasing the conductivity of the carbons. That active pore space utilization is defined as gravimetric capacitance per unit pore volume in pores smaller than 0.7 nm. Its magnitude is affected by conductivity of the carbon materials. The functional groups, besides pseudocapacitive contribution, increased the wettability and thus the degree of the pore space utilization. Graphene phase, owing to its conductivity, also took part in an insitu increase of the small pore accessibility and thus the capacitance of the composites via enhancing an electron transfer to small pores and thus imposing the reduction of groups blocking the pores for electrolyte ions.

Peats from West Kalimantan Province, Indonesia: The Distribution, Formation, Disturbances, Utilization and Conservation

NASA Astrophysics Data System (ADS)

Anshari, G. Z.

2011-12-01

A major portion of tropical peats, approximately between 180,000 and 210,000 km2, occurs in Indonesia. Peat is a water body that preserves and stores enormous organic Carbon of dead biomass vegetation. In a natural state, peat helps to maintain Carbon balance, hydrological cycle, and supply of dissolved and particulate organic matters into adjacent waters. Peat disturbances drive the change from Carbon sink function into Carbon source. This paper aims to discuss variability of tropical peats and peat degradation in West Kalimantan Province. The discussions include extent and formation, biodiversity, Carbon and water storage, major properties, utilization, peat disturbances (i.e. logging, forest conversion, drainage affects, and recurrent peat fires), and peat conservation. Management options for reducing peat fires and developing sustainable peat utilization are also explored. Data were collected from both coastal and inland peats in West Kalimantan Province. This paper declares that degradation of tropical peats in Indonesia is strongly associated with anthropogenic fires, peat forest conversion, and logging. To reduce speeds of peat degradation, the current utilization of peats needs being more intensive than extensive, and preventing water table drop by managing excessive drainage that leads to substantial decline of moisture in the upper peat layer, which is subsequently dry and flammable.

Growth and physiological responses of isohydric and anisohydric poplars to drought

Treesearch

Ziv Attia; Jean-Christophe Domec; Ram Oren; Danielle A. Way; Menachem Moshelion

2015-01-01

Understanding how different plants prioritize carbon gain and drought vulnerability under a variable water supply is important for predicting which trees will maximize woody biomass production under different environmental conditions. Here, Populus balsamifera (BS, isohydric genotype), P. simonii (SI, previously uncharacterized stomatal behaviour), and their cross, P....

Psychological and Metabolic Correlates of Obesity in African-Americans and Caucasians

DTIC Science & Technology

2006-01-01

29% fat, and 14.6% protein. Ensure was available in vanilla, chocolate, strawberry, and butter pecan . This liquid meal has been used previously in...oxygen uptake, carbon dioxide production, and respiratory exchange ratio by open circuit spirometry (KB20-CosMed, Italy ). Maximal exercise test

[Effects of long-term fertilization on microbial biomass carbon and nitrogen and on carbon source utilization of microbes in a red soil].

PubMed

Sun, Feng-xia; Zhang, Wei-hua; Xu, Ming-gang; Zhang, Wen-ju; Li, Zhao-qiang; Zhang, Jing-ye

2010-11-01

In order to explore the effects of long-term fertilization on the microbiological characters of red soil, soil samples were collected from a 19-year long-term experimental field in Qiyang of Hunan, with their microbial biomass carbon (MBC) and nitrogen (MBN) and microbial utilization ratio of carbon sources analyzed. The results showed that after 19-year fertilization, the soil MBC and MBN under the application of organic manure and of organic manure plus inorganic fertilizers were 231 and 81 mg x kg(-1) soil, and 148 and 73 mg x kg(-1) soil, respectively, being significantly higher than those under non-fertilization, inorganic fertilization, and inorganic fertilization plus straw incorporation. The ratio of soil MBN to total N under the application of organic manure and of organic manure plus inorganic fertilizers was averagely 6.0%, significantly higher than that under non-fertilization and inorganic fertilization. Biolog-ECO analysis showed that the average well color development (AWCD) value was in the order of applying organic manure plus inorganic fertilizers = applying organic manure > non-fertilization > inorganic fertilization = inorganic fertilization plus straw incorporation. Under the application of organic manure or of organic manure plus inorganic fertilizers, the microbial utilization rate of carbon sources, including carbohydrates, carboxylic acids, amino acids, polymers, phenols, and amines increased; while under inorganic fertilization plus straw incorporation, the utilization rate of polymers was the highest, and that of carbohydrates was the lowest. Our results suggested that long-term application of organic manure could increase the red soil MBC, MBN, and microbial utilization rate of carbon sources, improve soil fertility, and maintain a better crop productivity.

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

Storey, John Morse; Lewis Sr, Samuel Arthur; Szybist, James P

Gasoline direct injection (GDI) engines can offer improved fuel economy and higher performance over their port fuel-injected (PFI) counterparts, and are now appearing in increasingly more U.S. and European vehicles. Small displacement, turbocharged GDI engines are replacing large displacement engines, particularly in light-duty trucks and sport utility vehicles, in order for manufacturers to meet more stringent fuel economy standards. GDI engines typically emit the most particulate matter (PM) during periods of rich operation such as start-up and acceleration, and emissions of air toxics are also more likely during this condition. A 2.0 L GDI engine was operated at lambda ofmore » 0.91 at typical loads for acceleration (2600 rpm, 8 bar BMEP) on three different fuels; an 87 anti-knock index (AKI) gasoline (E0), 30% ethanol blended with the 87 AKI fuel (E30), and 48% isobutanol blended with the 87 AKI fuel. E30 was chosen to maximize octane enhancement while minimizing ethanol-blend level and iBu48 was chosen to match the same fuel oxygen level as E30. Particle size and number, organic carbon and elemental carbon (OC/EC), soot HC speciation, and aldehydes and ketones were all analyzed during the experiment. A new method for soot HC speciation is introduced using a direct, thermal desorption/pyrolysis inlet for the gas chromatograph (GC). Results showed high levels of aromatic compounds were present in the PM, including downstream of the catalyst, and the aldehydes were dominated by the alcohol blending.« less

Effect of CO2 on NADH production of denitrifying microbes via inhibiting carbon source transport and its metabolism.

PubMed

Wan, Rui; Chen, Yinguang; Zheng, Xiong; Su, Yinglong; Huang, Haining

2018-06-15

The potential effect of CO 2 on environmental microbes has drawn much attention recently. As an important section of the nitrogen cycle, biological denitrification requires electron donor to reduce nitrogen oxide. Nicotinamide adenine dinucleotide (NADH), which is formed during carbon source metabolism, is a widely reported electron donor for denitrification. Here we studied the effect of CO 2 on NADH production and carbon source utilization in the denitrifying microbe Paracoccus denitrificans. We observed that NADH level was decreased by 45.5% with the increase of CO 2 concentration from 0 to 30,000ppm, which was attributed to the significantly decreased utilization of carbon source (i.e., acetate). Further study showed that CO 2 inhibited carbon source utilization because of multiple negative influences: (1) suppressing the growth and viability of denitrifier cells, (2) weakening the driving force for carbon source transport by decreasing bacterial membrane potential, and (3) downregulating the expression of genes encoding key enzymes involved in intracellular carbon metabolism, such as citrate synthase, aconitate hydratase, isocitrate dehydrogenase, succinate dehydrogenase, and fumarate reductase. This study suggests that the inhibitory effect of CO 2 on NADH production in denitrifiers might deteriorate the denitrification performance in an elevated CO 2 climate scenario. Copyright © 2018 Elsevier B.V. All rights reserved.

The futility of utility: how market dynamics marginalize Adam Smith

NASA Astrophysics Data System (ADS)

McCauley, Joseph L.

2000-10-01

Economic theorizing is based on the postulated, nonempiric notion of utility. Economists assume that prices, dynamics, and market equilibria are supposed to be derived from utility. The results are supposed to represent mathematically the stabilizing action of Adam Smith's invisible hand. In deterministic excess demand dynamics I show the following. A utility function generally does not exist mathematically due to nonintegrable dynamics when production/investment are accounted for, resolving Mirowski's thesis. Price as a function of demand does not exist mathematically either. All equilibria are unstable. I then explain how deterministic chaos can be distinguished from random noise at short times. In the generalization to liquid markets and finance theory described by stochastic excess demand dynamics, I also show the following. Market price distributions cannot be rescaled to describe price movements as ‘equilibrium’ fluctuations about a systematic drift in price. Utility maximization does not describe equilibrium. Maximization of the Gibbs entropy of the observed price distribution of an asset would describe equilibrium, if equilibrium could be achieved, but equilibrium does not describe real, liquid markets (stocks, bonds, foreign exchange). There are three inconsistent definitions of equilibrium used in economics and finance, only one of which is correct. Prices in unregulated free markets are unstable against both noise and rising or falling expectations: Adam Smith's stabilizing invisible hand does not exist, either in mathematical models of liquid market data, or in real market data.

Environment, Renewable Energy and Reduced Carbon Emissions

NASA Technical Reports Server (NTRS)

Sen, S.; Khazanov, G.; Kishimoto, Y.

2011-01-01

Increased energy security and reduced carbon emissions pose significant challenges for science and technology. However, they also create substantial opportunities for innovative research and development. In this review paper, we highlight some of the key opportunities and mention public policies that are needed to enable the efforts and to maximize the probability of their success. Climate is among the uttermost nonlinear behaviors found around us. As recent studies showed the possible effect of cosmic rays on the Earth's climate, we investigate how complex interactions between the planet and its environment can be responsible for climate anomalies.

Wind farm and solar park effects on plant-soil carbon cycling: uncertain impacts of changes in ground-level microclimate.

PubMed

Armstrong, Alona; Waldron, Susan; Whitaker, Jeanette; Ostle, Nicholas J

2014-06-01

Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land-based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground-level climate by a magnitude that could affect the fundamental plant-soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground-level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land-based renewable energy sources to alter plant-soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research. © 2013 John Wiley & Sons Ltd.

Application of remote sensing in regional scale estimates of vegetation carbon budgets: The Belfix project

NASA Technical Reports Server (NTRS)

Veroustraete, Frank; Patyn, Johan; Myneni, R. B.

1994-01-01

A concept for coupling the remote sensing derived fraction of the absorbed photosynthetic active radiation (FAPAR) with a functional ecosystem model was developed. The study was named the Belfix procedure. The quantification of changes in carbon dynamics at the ecosystem level is a key issue in studies of global climatic change effects at the vegetation atmosphere interface. An operational procedure, for the determination of carbon fluxes at the regional scale (Belgian territory), is presented. The approach allows for the determination of the sink function of vegetation for carbon (dioxide). The phyto- and litter mass, photosynthetic assimilation, autotroph and heterotroph carbon fluxes and net ecosystem exchange (NEE) of carbon, were evaluated. The results suggest that a single solution can be obtained for ecosystem rates and states, applying an iterative procedure, based on minimizing the change in maximal seasonal green phytomass in function of yearly FAPAR temporal profiles. Total phytomass values obtained are in close range with those obtained by ground sampling.

Modeling Adversaries in Counterterrorism Decisions Using Prospect Theory.

PubMed

Merrick, Jason R W; Leclerc, Philip

2016-04-01

Counterterrorism decisions have been an intense area of research in recent years. Both decision analysis and game theory have been used to model such decisions, and more recently approaches have been developed that combine the techniques of the two disciplines. However, each of these approaches assumes that the attacker is maximizing its utility. Experimental research shows that human beings do not make decisions by maximizing expected utility without aid, but instead deviate in specific ways such as loss aversion or likelihood insensitivity. In this article, we modify existing methods for counterterrorism decisions. We keep expected utility as the defender's paradigm to seek for the rational decision, but we use prospect theory to solve for the attacker's decision to descriptively model the attacker's loss aversion and likelihood insensitivity. We study the effects of this approach in a critical decision, whether to screen containers entering the United States for radioactive materials. We find that the defender's optimal decision is sensitive to the attacker's levels of loss aversion and likelihood insensitivity, meaning that understanding such descriptive decision effects is important in making such decisions. © 2014 Society for Risk Analysis.

Optimal Resource Allocation in Library Systems

ERIC Educational Resources Information Center

Rouse, William B.

1975-01-01

Queueing theory is used to model processes as either waiting or balking processes. The optimal allocation of resources to these processes is defined as that which maximizes the expected value of the decision-maker's utility function. (Author)

DOT report for implementing OMB's information dissemination quality guidelines

DOT National Transportation Integrated Search

2002-08-01

Consistent with The Office of : Management and Budgets (OMB) Guidelines (for Ensuring and Maximizing the Quality, : Objectivity, Utility, and Integrity of Information Disseminated by Federal Agencies) : implementing Section 515 of the Treasury and...

Differences in the OC/EC Ratios that Characterize Ambient and Source Aerosols due to Thermal-Optical Analysis

EPA Science Inventory

Thermal-optical analysis (TOA) is typically used to measure the OC/EC (organic carbon/elemental carbon) and EC/TC (elemental carbon/total carbon) ratios in source and atmospheric aerosols. The present study utilizes a dual-optical carbon aerosol analyzer to examine the effects of...

An integrated prediction and optimization model of biogas production system at a wastewater treatment facility.

PubMed

Akbaş, Halil; Bilgen, Bilge; Turhan, Aykut Melih

2015-11-01

This study proposes an integrated prediction and optimization model by using multi-layer perceptron neural network and particle swarm optimization techniques. Three different objective functions are formulated. The first one is the maximization of methane percentage with single output. The second one is the maximization of biogas production with single output. The last one is the maximization of biogas quality and biogas production with two outputs. Methane percentage, carbon dioxide percentage, and other contents' percentage are used as the biogas quality criteria. Based on the formulated models and data from a wastewater treatment facility, optimal values of input variables and their corresponding maximum output values are found out for each model. It is expected that the application of the integrated prediction and optimization models increases the biogas production and biogas quality, and contributes to the quantity of electricity production at the wastewater treatment facility. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficient biological conversion of carbon monoxide (CO) to carbon dioxide (CO2) and for utilization in bioplastic production by Ralstonia eutropha through the display of an enzyme complex on the cell surface.

PubMed

Hyeon, Jeong Eun; Kim, Seung Wook; Park, Chulhwan; Han, Sung Ok

2015-06-25

An enzyme complex for biological conversion of CO to CO2 was anchored on the cell surface of the CO2-utilizing Ralstonia eutropha and successfully resulted in a 3.3-fold increase in conversion efficiency. These results suggest that this complexed system may be a promising strategy for CO2 utilization as a biological tool for the production of bioplastics.

High Temperature Raman Spectroscopy Study of the Conversion of Formate into Oxalate: Search for the Elusive CO 2 2 - Intermediate

NASA Astrophysics Data System (ADS)

Ryan, Charles; Mead, Anna; Lakkaraju, Prasad; Kaczur, Jerry; Bennett, Christopher; Dobbins, Tabbetha

Research on conversion of carbon dioxide into chemicals and fuels has the potential to address three problems of global relevance. (a) By removing carbon dioxide from the atmosphere, we are able to reduce the amount of greenhouse gases in the atmosphere, (b) by converting carbon dioxide into fuels, we are providing pathways for renewable energy sources, (c) by converting carbon dioxide into C2 and higher order compounds, and we are able to generate valuable precursors for organic synthesis. Formate salts are formed by the electrochemical reduction of carbon dioxide in aqueous media. However, in order to increase the utilization of carbon dioxide, methods need to be developed for the conversion of formate into compounds containing two carbon atoms such as oxalate or oxalic acid. Recently, we examined the thermal conversion of sodium formate into sodium oxalate utilizing a hydride ion catalyst. The proposed mechanism for this reaction involves the carbon dioxide dianion. Currently at NASA Goddard Space Flight Center.

Utilizing Forest Inventory and Analysis Data, Remote Sensing, and Ecosystem Models for National Forest System Carbon Assessments

Treesearch

Alexa J. Dugan; Richard A. Birdsey; Sean P. Healey; Christopher Woodall; Fangmin Zhang; Jing M. Chen; Alexander Hernandez; James B. McCarter

2015-01-01

Forested lands, representing the largest terrestrial carbon sink in the United States, offset 16% of total U.S. carbon dioxide emissions through carbon sequestration. Meanwhile, this carbon sink is threatened by deforestation, climate change and natural disturbances. As a result, U.S. Forest Service policies require that National Forests assess baseline carbon stocks...

Studies of the fate of sulfur trioxide in coal-fired utility boilers based on modified selected condensation methods.

PubMed

Cao, Yan; Zhou, Hongcang; Jiang, Wu; Chen, Chien-Wei; Pan, Wei-Ping

2010-05-01

The formation of sulfur trioxide (SO(3)) in coal-fired utility boilers can have negative effects on boiler performance and operation, such as fouling and corrosion of equipment, efficiency loss in the air preheater (APH), increase in stack opacity, and the formation of PM(2.5). Sulfur trioxide can also compete with mercury when bonding with injected activated carbons. Tests in a lab-scale reactor confirmed there are major interferences between fly ash and SO(3) during SO(3) sampling. A modified SO(3) procedure to maximize the elimination of measurement biases, based on the inertial-filter-sampling and the selective-condensation-collecting of SO(3), was applied in SO(3) tests in three full-scale utility boilers. For the two units burning bituminous coal, SO(3) levels starting at 20 to 25 ppmv at the inlet to the selective catalytic reduction (SCR), increased slightly across the SCR, owing to catalytic conversion of SO(2) to SO(3,) and then declined in other air pollutant control device (APCD) modules downstream to approximately 5 ppmv and 15 ppmv at the two sites, respectively. In the unit burning sub-bituminous coal, the much lower initial concentration of SO(3) estimated to be approximately 1.5 ppmv at the inlet to the SCR was reduced to about 0.8 ppmv across the SCR and to about 0.3 ppmv at the exit of the wet flue gas desulfurization (WFGD). The SO(3) removal efficiency across the WFGD scrubbers at the three sites was generally 35% or less. Reductions in SO(3) across either the APH or the dry electrostatic precipitator (ESP) in units burning high-sulfur bituminous coal were attributed to operating temperatures being below the dew point of SO(3).

Kinetics based reaction optimization of enzyme catalyzed reduction of formaldehyde to methanol with synchronous cofactor regeneration.

PubMed

Marpani, Fauziah; Sárossy, Zsuzsa; Pinelo, Manuel; Meyer, Anne S

2017-12-01

Enzymatic reduction of carbon dioxide (CO 2 ) to methanol (CH 3 OH) can be accomplished using a designed set-up of three oxidoreductases utilizing reduced pyridine nucleotide (NADH) as cofactor for the reducing equivalents electron supply. For this enzyme system to function efficiently a balanced regeneration of the reducing equivalents during reaction is required. Herein, we report the optimization of the enzymatic conversion of formaldehyde (CHOH) to CH 3 OH by alcohol dehydrogenase, the final step of the enzymatic redox reaction of CO 2 to CH 3 OH, with kinetically synchronous enzymatic cofactor regeneration using either glucose dehydrogenase (System I) or xylose dehydrogenase (System II). A mathematical model of the enzyme kinetics was employed to identify the best reaction set-up for attaining optimal cofactor recycling rate and enzyme utilization efficiency. Targeted process optimization experiments were conducted to verify the kinetically modeled results. Repetitive reaction cycles were shown to enhance the yield of CH 3 OH, increase the total turnover number (TTN) and the biocatalytic productivity rate (BPR) value for both system I and II whilst minimizing the exposure of the enzymes to high concentrations of CHOH. System II was found to be superior to System I with a yield of 8 mM CH 3 OH, a TTN of 160 and BPR of 24 μmol CH 3 OH/U · h during 6 hr of reaction. The study demonstrates that an optimal reaction set-up could be designed from rational kinetics modeling to maximize the yield of CH 3 OH, whilst simultaneously optimizing cofactor recycling and enzyme utilization efficiency. © 2017 Wiley Periodicals, Inc.

Integration of poly-3-(hydroxybutyrate-co-hydroxyvalerate) production by Haloferax mediterranei through utilization of stillage from rice-based ethanol manufacture in India and its techno-economic analysis.

PubMed

Bhattacharyya, Anirban; Jana, Kuntal; Haldar, Saubhik; Bhowmic, Asit; Mukhopadhyay, Ujjal Kumar; De, Sudipta; Mukherjee, Joydeep

2015-05-01

Haloferax mediterranei has potential for economical industrial-scale production of polyhydroxyalkanoate (PHA) as it can utilize cheap carbon sources, has capacity for nonsterile cultivation and allows simple product recovery. Molasses-based Indian distilleries are converting themselves to cereal-based distilleries. Waste stillage (14 l) of rice-based ethanol industry was used for the production of PHA by H. mediterranei in the simple plug-flow reactor configuration of the activated sludge process. Cells utilized stillage and accumulated 63 ± 3 % PHA of dry cell weight and produced 13.12 ± 0.05 g PHA/l. The product yield coefficient was 0.27 while 0.14 g/l h volumetric productivity was reached. Simultaneous lowering of 5-day biochemical oxygen demand and chemical oxygen demand values of stillage by 82 % was attained. The biopolymer was characterized as poly-3-(hydroxybutyrate-co-17.9 mol%-hydroxyvalerate) (PHBV). Directional properties of decanoic acid jointly with temperature-dependent water solubility in decanoic acid were employed for two-step desalination of the spent stillage medium in a cylindrical baffled-tank with an immersed heater and a stirrer holding axial and radial impellers. 99.3 % of the medium salts were recovered and re-used for PHA production. The cost of PHBV was estimated as US$2.05/kg when the annual production was simulated as 1890 tons. Desalination contributed maximally to the overall cost. Technology and cost-analysis demonstrate that PHA production integrated with ethanol manufacture is feasible in India. This study could be the basis for construction of a pilot plant.

A Preliminary Study of the Carbon Emissions Reduction Effects of Land Use Control

PubMed Central

Chuai, Xiaowei; Huang, Xianjin; Qi, Xinxian; Li, Jiasheng; Zuo, Tianhui; Lu, Qinli; Li, Jianbao; Wu, Changyan; Zhao, Rongqin

2016-01-01

Land use change not only directly influences carbon storage in terrestrial ecosystems but can also cause energy-related carbon emissions. This study examined spatiotemporal land use change across Jiangsu Province, China; calculated vegetation carbon storage loss caused by land use change and energy-related carbon emissions; analysed the relationship among land use change, carbon emissions and social-economic development; and optimized land use structure to maximize carbon storage. Our study found that 13.61% of the province’s land area underwent a change in type of land use between 1995 and 2010, mainly presented as built-up land expansion and cropland shrinkage, especially in southern Jiangsu. Land use change caused a 353.99 × 104 t loss of vegetation carbon storage loss. Energy-related carbon emissions increased 2.5 times from 1995 to 2013; the energy consumption structure has been improved to some extent while still relying on coal. The selected social-economic driving forces have strong relationships with carbon emissions and land use changes, while there are also other determinants driving land use change, such as land use policy. The optimized land use structure will slow the rate of decline in vegetation carbon storage compared with the period between 1995 and 2010 and will also reduce energy-related carbon emissions by 12%. PMID:27845428

A Preliminary Study of the Carbon Emissions Reduction Effects of Land Use Control.

PubMed

Chuai, Xiaowei; Huang, Xianjin; Qi, Xinxian; Li, Jiasheng; Zuo, Tianhui; Lu, Qinli; Li, Jianbao; Wu, Changyan; Zhao, Rongqin

2016-11-15

Land use change not only directly influences carbon storage in terrestrial ecosystems but can also cause energy-related carbon emissions. This study examined spatiotemporal land use change across Jiangsu Province, China; calculated vegetation carbon storage loss caused by land use change and energy-related carbon emissions; analysed the relationship among land use change, carbon emissions and social-economic development; and optimized land use structure to maximize carbon storage. Our study found that 13.61% of the province's land area underwent a change in type of land use between 1995 and 2010, mainly presented as built-up land expansion and cropland shrinkage, especially in southern Jiangsu. Land use change caused a 353.99 × 10 4 t loss of vegetation carbon storage loss. Energy-related carbon emissions increased 2.5 times from 1995 to 2013; the energy consumption structure has been improved to some extent while still relying on coal. The selected social-economic driving forces have strong relationships with carbon emissions and land use changes, while there are also other determinants driving land use change, such as land use policy. The optimized land use structure will slow the rate of decline in vegetation carbon storage compared with the period between 1995 and 2010 and will also reduce energy-related carbon emissions by 12%.

Preparation of granular activated carbons from yellow mombin fruit stones for CO2 adsorption.

PubMed

Fiuza, Raildo Alves; Medeiros de Jesus Neto, Raimundo; Correia, Laise Bacelar; Carvalho Andrade, Heloysa Martins

2015-09-15

Stones of yellow mombin, a native fruit of the tropical America and West Indies, were used as starting materials to produce activated carbons, subsequently used as adsorbent for CO2 capture. The carbonaceous materials were either chemically activated with HNO3, H3PO4 and KOH or physically activated with CO2. The carbon samples were characterized by SEM, EDX, TG/DTA, Raman spectroscopy, physical adsorption for textural analysis and by acid-base titrations. The CO2 adsorption capacity and adsorption cycles were investigated by TG. The results indicate that the capacity of CO2 adsorption may be maximized on highly basic surfaces of micropores smaller than 1 nm. The KOH activated carbon showed high and stable capacity of CO2 adsorption after 10 cycles. Copyright © 2015 Elsevier Ltd. All rights reserved.

β-Sitosterol: supercritical carbon dioxide extraction from sea buckthorn (Hippophae rhamnoides L.) seeds.

PubMed

Sajfrtová, Marie; Licková, Ivana; Wimmerová, Martina; Sovová, Helena; Wimmer, Zdenek

2010-04-22

Supercritical fluid extraction represents an efficient and environmentally friendly technique for isolation of phytosterols from different plant sources. Sea buckthorn (Hippophae rhamnoides L.) seeds were extracted with supercritical carbon dioxide at pressures ranging from 15-60 MPa and temperatures of 40-80 degrees C. Oil and β-sitosterol yields were measured in the extraction course and compared with Soxhlet extraction with hexane. The average yield of β-sitosterol was 0.31 mg/g of seeds. The maximum concentration of β-sitosterol in the extract, 0.5% w/w, was achieved at 15 MPa, 40 degrees C, and a carbon dioxide consumption of 50 g/g of seeds. The extraction rate was maximal at 60 MPa and 40 degrees C. Both β-sitosterol yield and its concentration in the extract obtained with hexane were lower than with carbon dioxide.

Study of detecting mechanism of carbon nanotubes gas sensor based on multi-stable stochastic resonance model.

PubMed

Jingyi, Zhu

2015-01-01

The detecting mechanism of carbon nanotubes gas sensor based on multi-stable stochastic resonance (MSR) model was studied in this paper. A numerically stimulating model based on MSR was established. And gas-ionizing experiment by adding electronic white noise to induce 1.65 MHz periodic component in the carbon nanotubes gas sensor was performed. It was found that the signal-to-noise ratio (SNR) spectrum displayed 2 maximal values, which accorded to the change of the broken-line potential function. The experimental results of gas-ionizing experiment demonstrated that periodic component of 1.65 MHz had multiple MSR phenomena, which was in accordance with the numerical stimulation results. In this way, the numerical stimulation method provides an innovative method for the detecting mechanism research of carbon nanotubes gas sensor.

Initial development and performance evaluation of a process for formation of dense carbon by pyrolysis of methane

NASA Technical Reports Server (NTRS)

Noyes, G. P.; Cusick, R. J.

1985-01-01

The three steps in pyrolytic carbon formation are: (1) gaseous hydrocarbon polymerization and aromatic formation; (2) gas-phase condensation and surface adsorption/impingement of polyaromatic hydrocarbon; and (3) final dehydration to carbon. The structure of the carbon in the various stages of formation is examined. The apparatuses and experimental procedures for the pyrolysis of methane in a 60 cm long quartz reactor tube at temperatures ranging from 1400-1600 K are described. The percentage of carbon converted and its density are calculated and tabularly presented. The results reveal that dense carbon formation is maximized and soot eliminated by this procedure. It is observed that conversion efficiency depends on the composition of the inlet gas and conversion increases with increasing temperature. Based on the experimental data a three-man carbon reactor subsystem (CRS) is developed; the functions of the Sabatier Methanation Reactor, two carbon formation reactors and fluid handling components of the CRS are analyzed. The CRS forms 16 kg of carbon at a rate of 0.8 kg/day for 20 days in a two percent volume density quartz wool packing at temperature of 1500-1600 K.

Optimal threshold estimator of a prognostic marker by maximizing a time-dependent expected utility function for a patient-centered stratified medicine.

PubMed

Dantan, Etienne; Foucher, Yohann; Lorent, Marine; Giral, Magali; Tessier, Philippe

2018-06-01

Defining thresholds of prognostic markers is essential for stratified medicine. Such thresholds are mostly estimated from purely statistical measures regardless of patient preferences potentially leading to unacceptable medical decisions. Quality-Adjusted Life-Years are a widely used preferences-based measure of health outcomes. We develop a time-dependent Quality-Adjusted Life-Years-based expected utility function for censored data that should be maximized to estimate an optimal threshold. We performed a simulation study to compare estimated thresholds when using the proposed expected utility approach and purely statistical estimators. Two applications illustrate the usefulness of the proposed methodology which was implemented in the R package ROCt ( www.divat.fr ). First, by reanalysing data of a randomized clinical trial comparing the efficacy of prednisone vs. placebo in patients with chronic liver cirrhosis, we demonstrate the utility of treating patients with a prothrombin level higher than 89%. Second, we reanalyze the data of an observational cohort of kidney transplant recipients: we conclude to the uselessness of the Kidney Transplant Failure Score to adapt the frequency of clinical visits. Applying such a patient-centered methodology may improve future transfer of novel prognostic scoring systems or markers in clinical practice.

Greenhouse Gas Emission Mitigation And Agriculture, Trade-off Or Win-win Situation: Bioeconomic Farm Modelling In The Sudanian Area of Burkina Faso

NASA Astrophysics Data System (ADS)

Some, T. E.; Barbier, B.

2015-12-01

Climate changes talks regularly underline that developing countries' agriculture could play a stronger role in GHGs mitigation strategies and benefit from the Kyoto Protocol program of subsidies. Scientists explain that agriculture can contribute to carbon mitigation by storing more carbon in the soil through greener cropping systems. In this context, a growing number of research projects have started to investigate how developing countries agriculture can contribute to these objectives. The clean development mechanism (CDM) proposed in the Kyoto protocol is one particular policy instrument that can incite farmers to mitigate the GHG balance towards more sequestration and less emission. Some economists such as Michael Porter think that environmental regulation lead to a win-win outcome, in which case subsidies are not necessary. If it is a trade-off between incomes and the environment, subsidies are required. CDM can be mobilized to support the mitigation strategy. Agriculture implies the use of inputs. Reducing the emission implies the reduction of those inputs which will in turn imply a yield decrease. The study aims to assess whether this measure will imply a trade-off between environmental and economic objectives or a win-win situation. I apply this study to the case of small farmers in Burkina Faso through environmental instruments such as the emissions limits and agroforestry using a bioeconomic model, in which the farmers maximize their utility subject to constraints. The study finds that the limitation of emissions in annual crops production involves a trade-off. by impacting negatively their net cash come. By integrating perennial crops in the farming system, the farmers' utility increases. Around 6,118 kg are sequestrated individually. By computing the value on this carbon balance, farmers' net cash incomes go better. Then practicing agroforestry is a win-win situation, as they reach a higher level of income, and reduce emissions. Policymakers must encourage small farmers to integrate perennial crops in their annual crops system. Most of small farmers are living below the poverty line. Limiting emissions will get worse their life conditions. To reach the emission reduction objective in the annual crops system, subsidies are needed in order to compensate the income lost through the CDM.

Plasma Pyrolysis Assembly Regeneration Evaluation

NASA Technical Reports Server (NTRS)

Medlen, Amber; Abney, Morgan B.; Miller, Lee A.

2011-01-01

In April 2010 the Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS). This technology requires hydrogen to recover oxygen from carbon dioxide. This results in the production of water and methane. Water is electrolyzed to provide oxygen to the crew. Methane is vented to space resulting in a loss of valuable hydrogen and unreduced carbon dioxide. This is not critical for ISS because of the water resupply from Earth. However, in order to have enough oxygen for long-term missions, it will be necessary to recover the hydrogen to maximize oxygen recovery. Thus, the Plasma Pyrolysis Assembly (PPA) was designed to recover hydrogen from methane. During operation, the PPA produces small amounts of carbon that can ultimately reduce performance by forming on the walls and windows of the reactor chamber. The carbon must be removed, although mechanical methods are highly inefficient, thus chemical methods are of greater interest. The purpose of this effort was to determine the feasibility of chemically removing the carbon from the walls and windows of a PPA reactor using a pure carbon dioxide stream.

Modification of carbon fiber surfaces via grafting with Meldrum's acid

NASA Astrophysics Data System (ADS)

Cuiqin, Fang; Jinxian, Wu; Julin, Wang; Tao, Zhang

2015-11-01

The mechanism of Meldrum's acid modifying carbon fiber surfaces was investigated in this work. The existing carbonyl groups of carbon fibers were grafted with Meldrum's acid to create carboxylic functionalized surfaces. The surface functionalization effect was detected with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The XPS results showed that the relative content of carboxylic groups on carbon fiber surfaces was increased from initial 1.41% to 7.84%, however, that of carbonyl groups was decreased from 23.11% to 13.28% after grafting reaction. The SEM, AFM and TGA results indicated that the surfaces of carbon fibers neither etched nor generated coating. The tensile strength of carbon fibers was preserved after grafting reaction according to single fiber tensile strength tests. The fibers were well combined with matrix and the maximal interlaminar shear strength (ILSS) of carbon fiber/epoxy resin composites was sharply increased approximately 74% after functionalization. The effects of acetic acid and sonication on the degree of the surface functionalization were also studied.

Intelligent transportation systems : tools to maximize state transportation investments

DOT National Transportation Integrated Search

1997-07-28

This Issue Brief summarizes national ITS goals and state transportation needs. It reviews states experience with ITS to date and discusses the utility of ITS technologies to improve transportation infrastructure. The Issue Brief also provides cost...

Carbon source utilization and inhibitor tolerance of 45 oleaginous yeast species

PubMed Central

Sitepu, Irnayuli; Selby, Tylan; Lin, Ting; Zhu, Shirley; Boundy-Mills, Kyria

2014-01-01

Conversion of lignocellulosic hydrolysates to lipids using oleaginous (high lipid) yeasts requires alignment of the hydrolysate composition with the characteristics of the yeast strain, including ability to utilize certain nutrients, ability to grow independently of costly nutrients such as vitamins, and ability to tolerate inhibitors. Some combination of these characteristics may be present in wild strains. In this study, 48 oleaginous yeast strains belonging to 45 species were tested for ability to utilize carbon sources associated with lignocellulosic hydrolysates, tolerate inhibitors, and grow in medium without supplemented vitamins. Some well-studied oleaginous yeast species, as well as some that have not been frequently utilized in research or industrial production, emerged as promising candidates for industrial use due to ability to utilize many carbon sources, including Cryptococcus aureus, Cryptococcus laurentii, Hanaella aff. zeae, Tremella encephala, and Trichosporon coremiiforme. Other species excelled in inhibitor tolerance, including Candida aff. tropicalis, Cyberlindnera jadinii, Metschnikowia pulcherrima Schwanniomyces occidentalis and Wickerhamomyces ciferii. No yeast tested could utilize all carbon sources and tolerate all inhibitors tested. These results indicate that yeast strains should be selected based on characteristics compatible with the composition of the targeted hydrolysate. Other factors to consider include the production of valuable co-products such as carotenoids, availability of genetic tools, biosafety level, and flocculation of the yeast strain. The data generated in this study will aid in aligning yeasts with compatible hydrolysates for conversion of carbohydrates to lipids to be used for biofuels and other oleochemicals. PMID:24818698

Liquid carbon dioxide absorbents, methods of using the same, and related system

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

Perry, Robert James; Soloveichik, Grigorii Lev; Rubinsztajn, Malgorzata Iwona

A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO 2 or have a high-affinity for CO 2, and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO 2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

Liquid carbon dioxide absorbents, methods of using the same, and related systems

DOEpatents

O'Brien, Michael Joseph; Perry, Robert James; Lam, Tunchiao Hubert; Soloveichik, Grigorii Lev; Kniajanski, Sergei; Lewis, Larry Neil; Rubinsztajn, Malgorzata Iwona; Hancu, Dan

2016-09-13

A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO.sub.2 or have a high-affinity for CO.sub.2; and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO.sub.2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

Developing Age Models to Utilize High Arctic Coastal Sediments for Paleoclimate Research: Results from the Colville Delta and Simpson Lagoon, Alaska

NASA Astrophysics Data System (ADS)

Miller, A. J.; Allison, M. A.; Bianchi, T. S.; Marcantonio, F.

2012-12-01

Sediment cores collected from Simpson Lagoon on the inner Beaufort Sea shelf adjacent to the Colville River delta, AK are being utilized to develop new, high-resolution (sub-decadal scale) archives of the 0-3,000 year Arctic paleoclimate record necessary to assess natural and anthropogenic climate variability. An imperative first step for developing a new paleoclimate archive is to establish methodologies for constraining the age-depth relationship. Naturally occurring and bomb-produced radioisotopes have been utilized in sediments to constrain downcore variability of accumulation rates on 100-103 y timescales, but this methodology is complicated by low activities of many of these tracers at high latitudes. The present study utilizes the combination of a (1) multi-tracer approach and a (2) tailored measurement strategy to overcome this limitation. 210Pb and 137Cs analyses were conducted on the fine (<32μm) sediment fraction to maximize measurable activity and to minimize radioisotope activity variability resulting from changes in grain size: 137Cs geochronologies proved more reliable in this setting and revealed mm/y sediment accumulation in the lagoon. To corroborate the 137Cs results, 239,240Pu activities were analyzed for selected sites using ICP-MS which has ultra-low detection limits, and yielded accumulation rates that matched the Cs geochronology. Age model development for the remainder of the core lengths (>~100 y in age) were completed using radiocarbon dating of benthic foraminifera tests, which proved the only datable in situ carbon available in this sediment archive. These dates have been used to constrain the ages of acoustic reflectors in CHIRP subbottom seismic records collected from the lagoon. Using this age control, spatial patterns of lagoonal sediment accumulation over the last ~3 ky were derived from the CHIRP data. Two depocenters are identified and validate combining age-dated coring with high-resolution seismic profiling to identify areas of the highest temporal resolution for Arctic paleoclimate research in coastal sediments.

[Carbon Source Utilization Characteristics of Soil Microbial Community for Apple Orchard with Interplanting Herbage].

PubMed

Du, Yi-fei; Fang, Kai-kai; Wang, Zhi-kang; Li, Hui-ke; Mao, Peng-juan; Zhang, Xiang-xu; Wang, Jing

2015-11-01

As soil fertility in apple orchard with clean tillage is declined continuously, interplanting herbage in orchard, which is a new orchard management model, plays an important role in improving orchard soil conditions. By using biolog micro-plate technique, this paper studied the functional diversity of soil microbial community under four species of management model in apple orchards, including clear tillage model, interplanting white clover model, interplanting small crown flower model and interplanting cocksfoot model, and the carbon source utilization characteristics of microbial community were explored, which could provide a reference for revealing driving mechanism of ecological process of orchard soil. The results showed that the functional diversity of microbial community had a significant difference among different treatments and in the order of white clover > small crown flower > cocksfoot > clear tillage. The correlation analysis showed that the average well color development (AWCD), Shannon index, Richness index and McIntosh index were all highly significantly positively correlated with soil organic carbon, total nitrogen, microbial biomass carbon, and Shannon index was significantly positively correlated with soil pH. The principal component analysis and the fingerprints of the physiological carbon metabolism of the microbial community demonstrated that grass treatments improved carbon source metabolic ability of soil microbial community, and the soil microbes with perennial legumes (White Clover and small crown flower) had a significantly higher utilization rate in carbohydrates (N-Acetyl-D-Glucosamine, D-Mannitol, β-Methyl-D-Glucoside), amino acids (Glycyl-L-Glutamic acid, L-Serine, L-Threonine) and polymers (Tween 40, Glycogen) than the soil microbes with clear tillage. It was considered that different treatments had the unique microbial community structure and peculiar carbon source utilization characteristics.

Nutrient demand and fungal access to resources control the carbon allocation to the symbiotic partners in tripartite interactions of Medicago truncatula.

PubMed

Kafle, Arjun; Garcia, Kevin; Wang, Xiurong; Pfeffer, Philip E; Strahan, Gary D; Bücking, Heike

2018-06-02

Legumes form tripartite interactions with arbuscular mycorrhizal (AM) fungi and rhizobia, and both root symbionts exchange nutrients against carbon from their host. The carbon costs of these interactions are substantial, but our current understanding of how the host controls its carbon allocation to individual root symbionts is limited. We examined nutrient uptake and carbon allocation in tripartite interactions of Medicago truncatula under different nutrient supply conditions, and when the fungal partner had access to nitrogen, and followed the gene expression of several plant transporters of the SUT and SWEET family. Tripartite interactions led to synergistic growth responses and stimulated the phosphate and nitrogen uptake of the plant. Plant nutrient demand but also fungal access to nutrients played an important role for the carbon transport to different root symbionts, and the plant allocated more carbon to rhizobia under nitrogen demand, but more carbon to the fungal partner when nitrogen was available. These changes in carbon allocation were consistent with changes in the SUT and SWEET expression. Our study provides important insights into how the host plant controls its carbon allocation under different nutrient supply conditions and changes its carbon allocation to different root symbionts to maximize its symbiotic benefits. This article is protected by copyright. All rights reserved.

Novel approach to engineer strains for simultaneous sugar utilization.

PubMed

Gawand, Pratish; Hyland, Patrick; Ekins, Andrew; Martin, Vincent J J; Mahadevan, Radhakrishnan

2013-11-01

Use of lignocellulosic biomass as a second generation feedstock in the biofuels industry is a pressing challenge. Among other difficulties in using lignocellulosic biomass, one major challenge is the optimal utilization of both 6-carbon (glucose) and 5-carbon (xylose) sugars by industrial microorganisms. Most industrial microorganisms preferentially utilize glucose over xylose owing to the regulatory phenomenon of carbon catabolite repression (CCR). Microorganisms that can co-utilize glucose and xylose are of considerable interest to the biofuels industry due to their ability to simplify the fermentation processes. However, elimination of CCR in microorganisms is challenging due to the multiple coordinating mechanisms involved. We report a novel algorithm, SIMUP, which finds metabolic engineering strategies to force co-utilization of two sugars, without targeting the regulatory pathways of CCR. Mutants of Escherichia coli based on SIMUP algorithm showed predicted growth phenotypes and co-utilized glucose and xylose; however, consumed the sugars slower than the wild-type. Some solutions identified by the algorithm were based on stoichiometric imbalance and were not obvious from the metabolic network topology. Furthermore, sequencing studies on the genes involved in CCR showed that the mechanism for co-utilization of the sugars could be different from previously known mechanisms. Copyright © 2013 Elsevier Inc. All rights reserved.

Biocompatible yogurt carbon dots: evaluation of utilization for medical applications

NASA Astrophysics Data System (ADS)

Dinç, Saliha; Kara, Meryem; Demirel Kars, Meltem; Aykül, Fatmanur; Çiçekci, Hacer; Akkuş, Mehmet

2017-09-01

In this study, carbon dots (CDs) were produced from yogurt, a fermented milk product, via microwave-assisted process (800 W) in 30 min without using any additional chemical agents. Yogurt CDs had outstanding nitrogen and oxygen ratios. These dots were monodisperse and about 2 nm sized. The toxicological assessments of yogurt carbon dots in human cancer cells and normal epithelial cells and their fluorescence imaging in living cell system were carried out. Yogurt carbon dots had intense fluorescent signal under confocal microscopy and good fluorescence stability in living cell system. The resulting yogurt carbon dots exhibited high biocompatibility up to 7.1 mg/mL CD concentration which may find utilization in medical applications such as cellular tracking, imaging and drug delivery. Yogurt carbon dots have potential to be good diagnostic agents to visualize cancer cells which may be developed as a therapeutic carrier.

Aqueous carbon black dispersions prepared with steam jet-cooked corn starch

USDA-ARS?s Scientific Manuscript database

The utilization of jet-cooked waxy and normal corn starch to prepare aqueous dispersions of hydrophobic carbon black (Vulcan XC-72R) is reported. Blending carbon black (CB) into aqueous jet-cooked dispersions of starch followed by high pressure homogenization produced stable aqueous carbon black di...

Long term results of early density management of a third growth redwood stand

Treesearch

Lynn A. Webb; John-Pascal Berrill; James L. Lindquist

2017-01-01

Precommercial or early thinning of regenerating redwood forests can support management objectives including maximizing yield, forest structure restoration, and promoting carbon sequestration. We present data collected over 30 years following a precommercial thinning (PCT) in a 19 year-old naturally regenerated and planted coast redwood (Sequoia sempervirens ...

Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

NASA Technical Reports Server (NTRS)

Cassell, Alan M.; Meyyappan, M.

2004-01-01

The multitude of considerations facing nanostructure growth and integration lends itself to combinatorial optimization approaches. Rapid optimization becomes even more important with wafer-scale growth and integration processes. Here we discuss methodology for developing plasma enhanced CVD growth techniques for achieving individual, vertically aligned carbon nanostructures that show excellent properties as ultrasensitive electrodes for nucleic acid detection. We utilize high throughput strategies for optimizing the upstream and downstream processing and integration of carbon nanotube electrodes as functional elements in various device types. An overview of ultrasensitive carbon nanotube based sensor arrays for electrochemical bio-sensing applications and the high throughput methodology utilized to combine novel electrode technology with conventional MEMS processing will be presented.

Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

NASA Technical Reports Server (NTRS)

Cassell, Alan M.; Li, J.; Ye, Q.; Koehne, J.; Chen, H.; Meyyappan, M.

2004-01-01

The multitude of considerations facing nanostructure growth and integration lends itself to combinatorial optimization approaches. Rapid optimization becomes even more important with wafer-scale growth and integration processes. Here we discuss methodology for developing plasma enhanced CVD growth techniques for achieving individual, vertically aligned carbon nanostructures that show excellent properties as ultrasensitive electrodes for nucleic acid detection. We utilize high throughput strategies for optimizing the upstream and downstream processing and integration of carbon nanotube electrodes as functional elements in various device types. An overview of ultrasensitive carbon nanotube based sensor arrays for electrochemical biosensing applications and the high throughput methodology utilized to combine novel electrode technology with conventional MEMS processing will be presented.

Deformation and Stress Response of Carbon Nanotubes/UHMWPE Composites under Extensional-Shear Coupling Flow

NASA Astrophysics Data System (ADS)

Wang, Junxia; Cao, Changlin; Yu, Dingshan; Chen, Xudong

2018-02-01

In this paper, the effect of varying extensional-shear couple loading on deformation and stress response of Carbon Nanotubes/ ultra-high molecular weight polyethylene (CNTs/UHMWPE) composites was investigated using finite element numerical simulation, with expect to improve the manufacturing process of UHMWPE-based composites with reduced stress and lower distortion. When applying pure extensional loading and pure X-Y shear loading, it was found that the risk of a structural breakage greatly rises. For identifying the coupling between extensional and shear loading, distinct generations of force loading were defined by adjusting the magnitude of extensional loading and X-Y shear loading. It was shown that with the decrement of X-Y shear loading the deformation decreases obviously where the maximal Mises stress in Z-direction at 0.45 m distance is in the range from 24 to 10 MPa and the maximal shear stress at 0.61 m distance is within the range from 0.9 to 0.3 MPa. In addition, all the stresses determined were clearly below the yield strength of CNTs/UHMWPE composites under extensional-shear couple loading.

Aspirin does not affect exercise performance.

PubMed

Roi, G S; Garagiola, U; Verza, P; Spadari, G; Radice, D; Zecca, L; Cerretelli, P

1994-07-01

A single-blind, cross-over study was carried out to evaluate the effects of acetylsalicylic acid (ASA) on cardiorespiratory performance during exercise. Eighteen young men, 9 athletes and 9 untrained but active subjects, performed a progressive maximal exercise test on a cycle ergometer (30 watt, 3 min steps, starting at 60 watt) on three different occasions, after a single administration of plain aspirin (1000mg of ASA), chewable buffered aspirin (1000mg of ASA and 600 mg of calcium carbonate) and placebo. Continuous measurement of breath-by-breath ventilation, oxygen consumption, carbon dioxide output, respiratory frequency and heart rate was carried-out at rest and during the exercise test. Blood lactate concentration was measured just before the start of exercise and at the third minute of each step in order to detect the anaerobic threshold. The pharmacokinetics of aspirin during exercise was also investigated in ten of the eighteen participants. The analysis of all investigated variables did not show any statistically significant difference between treatments, suggesting that a single dose of 1000mg of aspirin does not affect physical performance during submaximal and maximal exercise.

Hybrid Heat Exchangers

NASA Technical Reports Server (NTRS)

Tu, Jianping Gene; Shih, Wei

2010-01-01

A hybrid light-weight heat exchanger concept has been developed that uses high-conductivity carbon-carbon (C-C) composites as the heat-transfer fins and uses conventional high-temperature metals, such as Inconel, nickel, and titanium as the parting sheets to meet leakage and structural requirements. In order to maximize thermal conductivity, the majority of carbon fiber is aligned in the fin direction resulting in 300 W/m.K or higher conductivity in the fin directions. As a result of this fiber orientation, the coefficient of thermal expansion (CTE) of the C-C composite in both non-fiber directions matches well with the CTE of various high-temperature metal alloys. This allows the joining of fins and parting sheets by using high-temperature braze alloys.

Methods for continuous direct carbon fuel cell operation with a circulating electrolyte slurry

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

Harjes, Daniel I.; Dineen, Jr., D. Andrew; Guo, Liang

The present invention relates to methods and systems related to fuel cells, and in particular, to direct carbon fuel cells. The methods and systems relate to cleaning and removal of components utilized and produced during operation of the fuel cell, regeneration of components utilized during operation of the fuel cell, and generating power using the fuel cell.

Carbon spectrum utilization by an indigenous strain of Pseudomonas aeruginosa NCIM 5514: Production, characterization and surface active properties of biosurfactant.

PubMed

Varjani, Sunita J; Upasani, Vivek N

2016-12-01

The present research work was undertaken with a mandate to study carbon spectrum utilization and structural characterization of biosurfactant produced by indigenous Pseudomonas aeruginosa NCIM 5514, which showed unique properties to utilize a large number of carbon sources effectively for production of biosurfactant, although glucose was the best carbon substrate. In Bushnell-Hass medium supplemented with glucose (1%, w/v), 3.178±0.071g/l biosurfactant was produced by this isolate in 96h. The biosurfactant produced showed surface tension and emulsification activity values from 29.14±0.05 to 62.29±0.13mN/m and 88.50±1.96 to 15.40±0.91%, respectively. Toluene showed highest emulsification activity followed by kerosene. However, kerosene exhibited emulsion stability for 30days. Biosurfactant was characterized as a mixture of di-rhamnolipid (Rha-Rha-C 10 -C 14:1 ) and mono-rhamnolipid (Rha-C 8 -C 10 ) by FTIR, ESI-MS and LC-MS techniques. High biosurfactant yield opens up doors for the isolate to find utility in various industries. Copyright © 2016 Elsevier Ltd. All rights reserved.

A High-Performing Direct Carbon Fuel Cell with a 3D Architectured Anode Operated Below 600 °C.

PubMed

Wu, Wei; Zhang, Yunya; Ding, Dong; He, Ting

2018-01-01

Direct carbon fuel cells (DCFCs) are highly efficient power generators fueled by abundant and cheap solid carbons. However, the limited triple-phase boundaries (TPBs) in the fuel electrode, due to the lack of direct contact among carbon, electrode, and electrolyte, inhibit the performance and result in poor fuel utilization. To address the challenges of low carbon oxidation activity and low carbon utilization, a highly efficient, 3D solid-state architected anode is developed to enhance the performance of DCFCs below 600 °C. The cell with the 3D textile anode framework, Gd:CeO 2 -Li/Na 2 CO 3 composite electrolyte, and Sm 0.5 Sr 0.5 CoO 3 cathode demonstrates excellent performance with maximum power densities of 143, 196, and 325 mW cm -2 at 500, 550, and 600 °C, respectively. At 500 °C, the cells can be operated steadily with a rated power density of ≈0.13 W cm -2 at a constant current density of 0.15 A cm -2 with a carbon utilization over 85.5%. These results, for the first time, demonstrate the feasibility of directly electrochemical oxidation of solid carbon at 500-600 °C, representing a promising strategy in developing high-performing fuel cells and other electrochemical systems via the integration of 3D architected electrodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monkeys choose as if maximizing utility compatible with basic principles of revealed preference theory

PubMed Central

Pastor-Bernier, Alexandre; Plott, Charles R.; Schultz, Wolfram

2017-01-01

Revealed preference theory provides axiomatic tools for assessing whether individuals make observable choices “as if” they are maximizing an underlying utility function. The theory evokes a tradeoff between goods whereby individuals improve themselves by trading one good for another good to obtain the best combination. Preferences revealed in these choices are modeled as curves of equal choice (indifference curves) and reflect an underlying process of optimization. These notions have far-reaching applications in consumer choice theory and impact the welfare of human and animal populations. However, they lack the empirical implementation in animals that would be required to establish a common biological basis. In a design using basic features of revealed preference theory, we measured in rhesus monkeys the frequency of repeated choices between bundles of two liquids. For various liquids, the animals’ choices were compatible with the notion of giving up a quantity of one good to gain one unit of another good while maintaining choice indifference, thereby implementing the concept of marginal rate of substitution. The indifference maps consisted of nonoverlapping, linear, convex, and occasionally concave curves with typically negative, but also sometimes positive, slopes depending on bundle composition. Out-of-sample predictions using homothetic polynomials validated the indifference curves. The animals’ preferences were internally consistent in satisfying transitivity. Change of option set size demonstrated choice optimality and satisfied the Weak Axiom of Revealed Preference (WARP). These data are consistent with a version of revealed preference theory in which preferences are stochastic; the monkeys behaved “as if” they had well-structured preferences and maximized utility. PMID:28202727

Monkeys choose as if maximizing utility compatible with basic principles of revealed preference theory.

PubMed

Pastor-Bernier, Alexandre; Plott, Charles R; Schultz, Wolfram

2017-03-07

Revealed preference theory provides axiomatic tools for assessing whether individuals make observable choices "as if" they are maximizing an underlying utility function. The theory evokes a tradeoff between goods whereby individuals improve themselves by trading one good for another good to obtain the best combination. Preferences revealed in these choices are modeled as curves of equal choice (indifference curves) and reflect an underlying process of optimization. These notions have far-reaching applications in consumer choice theory and impact the welfare of human and animal populations. However, they lack the empirical implementation in animals that would be required to establish a common biological basis. In a design using basic features of revealed preference theory, we measured in rhesus monkeys the frequency of repeated choices between bundles of two liquids. For various liquids, the animals' choices were compatible with the notion of giving up a quantity of one good to gain one unit of another good while maintaining choice indifference, thereby implementing the concept of marginal rate of substitution. The indifference maps consisted of nonoverlapping, linear, convex, and occasionally concave curves with typically negative, but also sometimes positive, slopes depending on bundle composition. Out-of-sample predictions using homothetic polynomials validated the indifference curves. The animals' preferences were internally consistent in satisfying transitivity. Change of option set size demonstrated choice optimality and satisfied the Weak Axiom of Revealed Preference (WARP). These data are consistent with a version of revealed preference theory in which preferences are stochastic; the monkeys behaved "as if" they had well-structured preferences and maximized utility.

Utilization of Activated Carbon Prepared from Aceh Coffee Grounds as Bio-sorbent for Treatment of Fertilizer Industrial Waste Water

NASA Astrophysics Data System (ADS)

Mariana, M.; Mahidin, M.; Mulana, F.; Aman, F.

2018-05-01

The people of Aceh are well known as coffee drinkers. Therefore, a lot of coffee shops have been established in Aceh in the past decade. The growing of coffee shops resulting to large amounts of coffee waste produced in Aceh Province that will become solid waste if not wisely utilized. The high carbon content in coffee underlined as background of this research to be utilized those used coffee grounds as bio-sorbent. The preparation of activated carbon from coffee grounds by using carbonization method that was initially activated with HCl was expected to increase the absorption capacity. The prepared activated carbon with high reactivity was applied to adsorb nitrite, nitrate and ammonia in wastewater outlet of PT. PIM wastewater pond. Morphological structure of coffee waste was analyzed by using Scanning Electron Microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The result showed that the adsorption capacity of iodine was equal to 856.578 mg/g. From the characterization results, it was concluded that the activated carbon from coffee waste complied to the permitted quality standards in accordance with the quality requirements of activated carbon SNI No. 06-3730-1995. Observed from the adsorption efficiency, the bio-sorbent showed a tendency of adsorbing more ammonia than nitrite and nitrate of PT. PIM wastewater with ammonia absorption efficiency of 56%.

Association between angiotensin-converting enzyme gene polymorphisms and exercise performance in patients with COPD.

PubMed

Zhang, Xiaolei; Wang, Chen; Dai, Huaping; Lin, Yingxiang; Zhang, Jun

2008-09-01

Recent studies have shown that polymorphisms of the angiotensin-converting enzyme (ACE) gene are closely associated with pulmonary disorders. The ACE gene is involved in the regulation of inflammatory reactions to lung injury, respiratory drive, erythropoiesis and tissue oxygenation. The hypothesis for this study was that the ACE gene may be associated with the ventilatory response to exercise and the aerobic work efficiency of skeletal muscle in patients with COPD. Sixty-one Chinese Han COPD patients and 57 healthy control subjects performed incremental cardiopulmonary exercise testing on a cycle ergometer. ACE genotypes were determined using PCR amplification. Resting lung function and blood gas index were not significantly different among the three ACE genotype COPD groups. Similarly, there were no significant differences in AT, maximal O(2) uptake, maximal O(2) pulse, maximal dyspnoea index, ventilatory response (DeltaVE/DeltaVCO(2)), O(2) cost of ventilation (VO(2)/W/VE), end-tidal partial pressure of carbon dioxide at maximal exercise and maximal SaO(2) among the three ACE genotype COPD patients. Maximal work load and aerobic work efficiency were higher in the COPD group with the II genotype than in those with the ID or DD genotype. There were no significant differences in resting lung function and cardiopulmonary exercise testing parameters among the three ACE genotype control groups. The ACE gene may be involved in the regulation of skeletal muscle aerobic work efficiency, but is not associated with the ventilatory responses to exercise in COPD patients.

Metabolically engineered glucose-utilizing Shewanella strains under anaerobic conditions.

PubMed

Choi, Donggeon; Lee, Sae Bom; Kim, Sohyun; Min, Byoungnam; Choi, In-Geol; Chang, In Seop

2014-02-01

Comparative genome analysis of Shewanella strains predicted that the strains metabolize preferably two- and three-carbon carbohydrates as carbon/electron source because many Shewanella genomes are deficient of the key enzymes in glycolysis (e.g., glucokinase). In addition, all Shewanella genomes are known to have only one set of genes associated with the phosphotransferase system required to uptake sugars. To engineer Shewanella strains that can utilize five- and six-carbon carbohydrates, we constructed glucose-utilizing Shewanella oneidensis MR-1 by introducing the glucose facilitator (glf; ZMO0366) and glucokinase (glk; ZMO0369) genes of Zymomonas mobilis. The engineered MR-1 strain was able to grow on glucose as a sole carbon/electron source under anaerobic conditions. The glucose affinity (Ks) and glucokinase activity in the engineered MR-1 strain were 299.46 mM and 0.259 ± 0.034 U/g proteins. The engineered strain was successfully applied to a microbial fuel cell system and exhibited current generation using glucose as the electron source. Copyright © 2013 Elsevier Ltd. All rights reserved.

Forest carbon management in the United States: 1600-2100

Treesearch

Richard A. Birdsey; Kurt Pregitzer; Alan Lucier

2006-01-01

This paper reviews the effects of past forest management on carbon stocks in the United States, and the challenges for managing forest carbon resources in the 21st century. Forests in the United States were in approximate carbon balance with the atmosphere from 1600-1800. Utilization and land clearing caused a large pulse of forest carbon emissions during the 19th...

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

White, Mark D.; McPherson, Brian J.; Grigg, Reid B.

Numerical simulation is an invaluable analytical tool for scientists and engineers in making predictions about of the fate of carbon dioxide injected into deep geologic formations for long-term storage. Current numerical simulators for assessing storage in deep saline formations have capabilities for modeling strongly coupled processes involving multifluid flow, heat transfer, chemistry, and rock mechanics in geologic media. Except for moderate pressure conditions, numerical simulators for deep saline formations only require the tracking of two immiscible phases and a limited number of phase components, beyond those comprising the geochemical reactive system. The requirements for numerically simulating the utilization and storagemore » of carbon dioxide in partially depleted petroleum reservoirs are more numerous than those for deep saline formations. The minimum number of immiscible phases increases to three, the number of phase components may easily increase fourfold, and the coupled processes of heat transfer, geochemistry, and geomechanics remain. Public and scientific confidence in the ability of numerical simulators used for carbon dioxide sequestration in deep saline formations has advanced via a natural progression of the simulators being proven against benchmark problems, code comparisons, laboratory-scale experiments, pilot-scale injections, and commercial-scale injections. This paper describes a new numerical simulator for the scientific investigation of carbon dioxide utilization and storage in partially depleted petroleum reservoirs, with an emphasis on its unique features for scientific investigations; and documents the numerical simulation of the utilization of carbon dioxide for enhanced oil recovery in the western section of the Farnsworth Unit and represents an early stage in the progression of numerical simulators for carbon utilization and storage in depleted oil reservoirs.« less

Maximizing performance in supercritical fluid chromatography using low-density mobile phases.

PubMed

Gritti, Fabrice; Fogwill, Michael; Gilar, Martin; Jarrell, Joseph A

2016-10-14

The performance of a 3.0mm×150mm column packed with 1.8μm fully porous HSS-SB-C 18 particles was investigated in supercritical fluid chromatography (SFC) with low-density, highly expansible carbon dioxide. These conditions are selected for the analysis of semi-volatile compounds. Elevated temperatures (>100°C) were then combined with low column back pressures (<100bar). In this work, the inlet temperature of pure carbon dioxide was set at 107°C, the active back pressure regulator (ABPR) pressure was fixed at 100bar, and the flow rate was set at 2.1mL/min at 12°C (liquefied carbon dioxide) and at an inlet column pressure close to 300bar. Nine n-alkylbenzenes (from benzene to octadecylbenzene) were injected under linear (no sample overload) conditions. The severe steepness of the temperature gradients across the column diameter were predicted from a simplified heat transfer model. Such conditions dramatically lower the column performance by affecting the symmetry of the peak shape. In order to cope with this problem, three different approaches were experimentally tested. They include (1) the decoupling and the proper selection of the inlet eluent temperature with respect to the oven temperature, (2) the partial thermal insulation of the column using polyethylene aerogel, and (3) the application of a high vacuum (10 -5 Torr provided by a turbo-molecular pump) in a housing chamber surrounding the whole column body. The results reveal that (1) the column efficiency can be maximized by properly selecting the difference between the eluent and the oven temperatures, (2) the mere wrapping of the column with an excellent insulating material is insufficient to fully eliminate heat exchanges by conduction and the undesirable radial density gradients across the column i.d., and (3) the complete thermal insulation of the SFC column under high vacuum allows to maximize the column efficiency by maintaining the integrity of the peak shape. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of a new genetic algorithm to solve the feedstock scheduling problem in an anaerobic digester

NASA Astrophysics Data System (ADS)

Cram, Ana Catalina

As worldwide environmental awareness grow, alternative sources of energy have become important to mitigate climate change. Biogas in particular reduces greenhouse gas emissions that contribute to global warming and has the potential of providing 25% of the annual demand for natural gas in the U.S. In 2011, 55,000 metric tons of methane emissions were reduced and 301 metric tons of carbon dioxide emissions were avoided through the use of biogas alone. Biogas is produced by anaerobic digestion through the fermentation of organic material. It is mainly composed of methane with a rage of 50 to 80% in its concentration. Carbon dioxide covers 20 to 50% and small amounts of hydrogen, carbon monoxide and nitrogen. The biogas production systems are anaerobic digestion facilities and the optimal operation of an anaerobic digester requires the scheduling of all batches from multiple feedstocks during a specific time horizon. The availability times, biomass quantities, biogas production rates and storage decay rates must all be taken into account for maximal biogas production to be achieved during the planning horizon. Little work has been done to optimize the scheduling of different types of feedstock in anaerobic digestion facilities to maximize the total biogas produced by these systems. Therefore, in the present thesis, a new genetic algorithm is developed with the main objective of obtaining the optimal sequence in which different feedstocks will be processed and the optimal time to allocate to each feedstock in the digester with the main objective of maximizing the production of biogas considering different types of feedstocks, arrival times and decay rates. Moreover, all batches need to be processed in the digester in a specified time with the restriction that only one batch can be processed at a time. The developed algorithm is applied to 3 different examples and a comparison with results obtained in previous studies is presented.

Final Technical Report

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

Resasco, Daniel; Lobban, Lance; Crossley, Steven

The goal was to develop a biomass conversion process that optimizes fractionation and conversion to maximize Carbon efficiency and Hydrogen consumption to obtain drop-in fuels. Selective fractionation of raw biomass was obtained via multi-stage thermal fractionation to produce different streams that are enriched in a particular chemical family (acids, furanics or phenolics). These streams were later catalytically upgraded in both liquid and vapor phase to perform C-C bond formation and hydrodeoxygenation. Among various upgrading strategies investigated we have identified an effective path in which cyclopentanone is a crucial intermediate that can be derived from furfural and other furanics obtained inmore » high concentrations from this thermal staged process. Cyclopentanone is a very versatile molecule, which can couple with itself to product high quality jet-fuel, or couple with phenolic or furanics to create long chain molecules. These (mono-oxygenated) compounds in the correct molecular weight fuel range can be hydrotreated to direct drop-in fuels. Interestingly, we have found that the conversion of furfural to cyclopentanone is not affected by the presence of acetic acid, and, more interestingly, it is enhanced by the presence of water. These are very significant findings, since water and acetic acid are always present in all streams from the primary conversion stage. These results have allowed to complete detailed life-cycle assessment and techno-economic analysis that have been back-fed to the experimentalists to refine the catalyst selection and process operations with the objective of maximizing C efficiency at minimum H utilization. These combined investigations have opened the possibility of an economically and technologically effective process that could result in commercial fuels produced from renewable sources at a cost that might be competitive with fossil fuels.« less

Multilayer Fiber Interfaces for Improved Environmental Resistance and Slip in Carbon Fiber Reinforced Composites

NASA Technical Reports Server (NTRS)

Babcock, Jason R.; Ramachandran, Gautham; Williams, Brian E.; Effinger, Michael R.

2004-01-01

Ultraviolet-enhanced chemical vapor deposition (UVCVD) has been developed to lower the required substrate temperature thereby allowing for the application of metal oxide-based coatings to carbon and ceramic fibers without causing significant fiber damage. An effort to expand this capability to other ceramic phases chosen to maximize oxidation protection in the likely event of matrix cracking and minimize possible reaction between the coating and fiber during long-term high temperature use will be presented along with studies aimed at the demonstration of these and other benefits for the next-generation interface coating systems being developed herein.

Analysis of dynamic hydrogen (H2) generation

NASA Astrophysics Data System (ADS)

Buford, Marcelle C.

2003-03-01

The focus of this research is on-demand hydrogen generation for applications such as electric vehicles and electric appliances. Hydrogen can be generated by steam reformation of alcohols, hydrocarbons and other hydrogen containing complexes. Steam reformation can be represented as a simple chemical reaction between an alcohol, commonly methanol, and water vapor to produce hydrogen and carbon dioxide. A fuel cell can then be employed to produce electrical power from hydrogen and air. Numerical and experimental techniques are employed to analyze the most appropriate reforming fuel to maximize H2 yield and minimize by-products of which carbon monoxide is the most harmful

Thermal adaptation of net ecosystem exchange

DOE PAGES

Yuan, W.; Luo, Y.; Liang, S.; ...

2011-06-06

Thermal adaptation of gross primary production and ecosystem respiration has been well documented over broad thermal gradients. However, no study has examined their interaction as a function of temperature, i.e. the thermal responses of net ecosystem exchange of carbon (NEE). Here in this study, we constructed temperature response curves of NEE against temperature using 380 site-years of eddy covariance data at 72 forest, grassland and shrubland ecosystems located at latitudes ranging from ~29° N to 64° N. The response curves were used to define two critical temperatures: transition temperature (T b) at which ecosystem transfer from carbon source to sinkmore » and optimal temperature (T o) at which carbon uptake is maximized. T b was strongly correlated with annual mean air temperature. T o was strongly correlated with mean temperature during the net carbon uptake period across the study ecosystems. Our results imply that the net ecosystem exchange of carbon adapts to the temperature across the geographical range due to intrinsic connections between vegetation primary production and ecosystem respiration.« less

Thermal adaptation of net ecosystem exchange

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

Yuan, W.; Luo, Y.; Liang, S.

Thermal adaptation of gross primary production and ecosystem respiration has been well documented over broad thermal gradients. However, no study has examined their interaction as a function of temperature, i.e. the thermal responses of net ecosystem exchange of carbon (NEE). Here in this study, we constructed temperature response curves of NEE against temperature using 380 site-years of eddy covariance data at 72 forest, grassland and shrubland ecosystems located at latitudes ranging from ~29° N to 64° N. The response curves were used to define two critical temperatures: transition temperature (T b) at which ecosystem transfer from carbon source to sinkmore » and optimal temperature (T o) at which carbon uptake is maximized. T b was strongly correlated with annual mean air temperature. T o was strongly correlated with mean temperature during the net carbon uptake period across the study ecosystems. Our results imply that the net ecosystem exchange of carbon adapts to the temperature across the geographical range due to intrinsic connections between vegetation primary production and ecosystem respiration.« less

Forest Ecosystem Processes at the Watershed Scale: Ecosystem services, feedback and evolution in developing mountainous catchments

NASA Astrophysics Data System (ADS)

Band, Larry

2010-05-01

Mountain watersheds provide significant ecosystem services both locally and for surrounding regions, including the provision of freshwater, hydropower, carbon sequestration, habitat, forest products and recreational/aesthetic opportunities. The hydrologic connectivity along hillslopes in sloping terrain provides an upslope subsidy of water and nutrients to downslope ecosystem patches, producing characteristic ecosystem patterns of vegetation density and type, and soil biogeochemical cycling. Recent work suggests that optimal patterns of forest cover evolve along these flowpaths which maximize net primary productivity and carbon sequestration at the hillslope to catchment scale. These watersheds are under significant pressure from potential climate change, changes in forest management, increasing population and development, and increasing demand for water export. As water balance and flowpaths are altered by shifting weather patterns and new development, the spatial distribution and coupling of water, carbon and nutrient cycling will spur the evolution of different ecosystem patterns. These issues have both theoretical and practical implications for the coupling of water, carbon and nutrient cycling at the landscape level, and the potential to manage watersheds for bundled ecosystem services. If the spatial structure of the ecosystem spontaneously adjusts to maximize landscape level use of limiting resources, there may be trade-offs in the level of services provided. The well known carbon-for-water tradeoff reflects the growth of forests to maximize carbon uptake, but also transpiration which limits freshwater availability in many biomes. We provide examples of the response of bundled ecosystem services to climate and land use change in the Southern Appalachian Mountains of the United States. These mountains have very high net primary productivity, biodiversity and water yields, and provide significant freshwater resources to surrounding regions. There has been a significant increase in population in the Southern Appalachians, with new building of second homes in steep headwaters, requiring significant expansion in high altitude roads, in contrast with traditional valley bottom development. With additional increases in hydrologic extremes (heavy precipitation and drought), and progressive changes in forest composition there has been increases in hazard from flash flooding, landslide activity and degraded water quality. The evaluation of integrated watershed impacts of the expected changes in climate and land management requires an interdisciplinary approach including direct feedbacks between ecological, hydrological, geomorphic and atmospheric processes within the framework of an adapting social system. Advances in this type of interdisciplinary research require a network of ecohydrologic observatories generating long term, multi-dimensional data, and a science community working across the interface of multiple fields. Adding individual and institutional behavior as an input or interactive component of watershed ecosystems remains a challenge that spans ecological, hydrological and social science.

Carbon Nanotube Biosensors for Space Molecule Detection and Clinical Molecular Diagnostics

NASA Technical Reports Server (NTRS)

Han, Jie

2001-01-01

Both space molecule detection and clinical molecule diagnostics need to develop ultra sensitive biosensors for detection of less than attomole molecules such as amino acids for DNA. However all the electrode sensor systems including those fabricated from the existing carbon nanotubes, have a background level of nA (nanoAmp). This has limited DNA or other molecule detection to nA level or molecules whose concentration is, much higher than attomole level. A program has been created by NASA and NCI (National Cancer Institute) to exploit the possibility of carbon nanotube based biosensors to solve this problem for both's interest. In this talk, I will present our effort on the evaluation and novel design of carbon nanotubes as electrode biosensors with strategies to minimize background currents while maximizing signal intensity.The fabrication of nanotube electrode arrays, immobilization of molecular probes on nanotube electrodes and in vitro biosensor testing will also be discussed.

New applications of carbon nanostructures in microbial fuel cells (MFC)

NASA Astrophysics Data System (ADS)

Kaca, W.; Żarnowiec, P.; Keczkowska, Justyna; Suchańska, M.; Czerwosz, E.; Kozłowski, M.

2014-11-01

In the studies presented we proposed a new application for nanocomposite carbon films (C-Pd). These films were evaluated as an anode material for Microbial Fuel Cells (MFCs) used for electrical current generation. The results of characterization of C-Pd films composed of carbon and palladium nanograins were obtained using the Physical Vapor Deposition (PVD) method. The film obtained by this method exhibits a multiphase structure composed of fullerene nanograins, amorphous carbon and palladium nanocrystals. Raman Spectroscopy (RS) and scanning electron microscopy (SEM) are used to characterize the chemical composition, morphology and topography of these films. We observed, for MFC with C-Pd anode, the highest electrochemical activity and maximal voltage density - 458 mV (20,8 mV/cm2) for Proteus mirabilis, 426 mV (19,4 mV/cm2) for Pseudomonas aeruginosa and 652 mV (29,6 mV/cm2) for sewage bacteria as the microbial catalyst.

A Brazilian network of carbon flux stations

NASA Astrophysics Data System (ADS)

Roberti, Débora R.; Acevedo, Otávio C.; Moraes, Osvaldo L. L.

2012-05-01

First Brasflux Workshop; Santa Maria, Rio Grande do Sul, Brazil, 14-15 November 2011 Last November, 33 researchers participated in a workshop to establish Brasflux, the Brazilian network of carbon flux stations, with the objective of integrating previous efforts and planning for the future. Among the participants were those leading ongoing flux observation projects and others planning to establish flux stations in the near future. International scientists also participated to share the experiences gained with other networks. The need to properly characterize terrestrial ecosystems for their roles in the global carbon, water, and energy budgets has motivated the implementation of hundreds of micrometeorological research sites throughout the world in recent years. The eddy covariance (EC) technique for turbulent flux determination is the preferred method to provide integral information on ecosystematmosphere exchanges. Integrating the observations regionally and globally has proven to be an effective approach to maximizing the usefulness of this technique for carbon cycle studies at multiple scales.

XPS Protocol for the Characterization of Pristine and Functionalized Single Wall Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Sosa, E. D.; Allada, R.; Huffman, C. B.; Arepalli, S.

2009-01-01

Recent interest in developing new applications for carbon nanotubes (CNT) has fueled the need to use accurate macroscopic and nanoscopic techniques to characterize and understand their chemistry. X-ray photoelectron spectroscopy (XPS) has proved to be a useful analytical tool for nanoscale surface characterization of materials including carbon nanotubes. Recent nanotechnology research at NASA Johnson Space Center (NASA-JSC) helped to establish a characterization protocol for quality assessment for single wall carbon nanotubes (SWCNTs). Here, a review of some of the major factors of the XPS technique that can influence the quality of analytical data, suggestions for methods to maximize the quality of data obtained by XPS, and the development of a protocol for XPS characterization as a complementary technique for analyzing the purity and surface characteristics of SWCNTs is presented. The XPS protocol is then applied to a number of experiments including impurity analysis and the study of chemical modifications for SWCNTs.

β-Sitosterol: Supercritical Carbon Dioxide Extraction from Sea Buckthorn (Hippophae rhamnoides L.) Seeds

PubMed Central

Sajfrtová, Marie; Ličková, Ivana; Wimmerová, Martina; Sovová, Helena; Wimmer, Zdeněk

2010-01-01

Supercritical fluid extraction represents an efficient and environmentally friendly technique for isolation of phytosterols from different plant sources. Sea buckthorn (Hippophae rhamnoides L.) seeds were extracted with supercritical carbon dioxide at pressures ranging from 15–60 MPa and temperatures of 40–80 °C. Oil and β-sitosterol yields were measured in the extraction course and compared with Soxhlet extraction with hexane. The average yield of β-sitosterol was 0.31 mg/g of seeds. The maximum concentration of β-sitosterol in the extract, 0.5% w/w, was achieved at 15 MPa, 40 °C, and a carbon dioxide consumption of 50 g/g of seeds. The extraction rate was maximal at 60 MPa and 40 °C. Both β-sitosterol yield and its concentration in the extract obtained with hexane were lower than with carbon dioxide. PMID:20480045

Electricity generation from carbon monoxide in a single chamber microbial fuel cell.

PubMed

Mehta, P; Hussain, A; Tartakovsky, B; Neburchilov, V; Raghavan, V; Wang, H; Guiot, S R

2010-05-05

Electricity production from carbon monoxide (CO) is demonstrated in a single chamber microbial fuel cell (MFC) with a CoTMPP-based air cathode. The MFC was inoculated with anaerobic sludge and continuously sparged with CO as a sole carbon source. Volumetric power output was maximized at a CO flow rate of 4.8LLR(-1)d(-1) reaching 6.4mWLR(-1). Several soluble and gaseous degradation products including hydrogen, methane, and acetate were detected, resulting in a relatively low apparent Coulombic efficiency of 8.7%. Tests also demonstrated electricity production from hydrogen and acetate with the highest and fastest increase in voltage exhibited after acetate injection. It is hypothesized that electricity generation in a CO-fed MFC is accomplished by a consortium of carboxydotrophic and carbon monoxide - tolerant anodophilic microorganisms. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

Sequestration and utilization of carbon dioxide by chemical and biological methods for biofuels and biomaterials by chemoautotrophs: Opportunities and challenges.

PubMed

Thakur, Indu Shekhar; Kumar, Manish; Varjani, Sunita J; Wu, Yonghong; Gnansounou, Edgard; Ravindran, Sindhu

2018-05-01

To meet the CO 2 emission reduction targets, carbon dioxide capture and utilization (CCU) comes as an evolve technology. CCU concept is turning into a feedstock and technologies have been developed for transformation of CO 2 into useful organic products. At industrial scale, utilization of CO 2 as raw material is not much significant as compare to its abundance. Mechanisms in nature have evolved for carbon concentration, fixation and utilization. Assimilation and subsequent conversion of CO 2 into complex molecules are performed by the photosynthetic and chemolithotrophic organisms. In the last three decades, substantial research is carry out to discover chemical and biological conversion of CO 2 in various synthetic and biological materials, such as carboxylic acids, esters, lactones, polymer biodiesel, bio-plastics, bio-alcohols, exopolysaccharides. This review presents an over view of catalytic transformation of CO 2 into biofuels and biomaterials by chemical and biological methods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Generation, capture, and utilization of industrial carbon dioxide.

PubMed

Hunt, Andrew J; Sin, Emily H K; Marriott, Ray; Clark, James H

2010-03-22

As a carbon-based life form living in a predominantly carbon-based environment, it is not surprising that we have created a carbon-based consumer society. Our principle sources of energy are carbon-based (coal, oil, and gas) and many of our consumer goods are derived from organic (i.e., carbon-based) chemicals (including plastics, fabrics and materials, personal care and cleaning products, dyes, and coatings). Even our large-volume inorganic-chemicals-based industries, including fertilizers and construction materials, rely on the consumption of carbon, notably in the form of large amounts of energy. The environmental problems which we now face and of which we are becoming increasingly aware result from a human-induced disturbance in the natural carbon cycle of the Earth caused by transferring large quantities of terrestrial carbon (coal, oil, and gas) to the atmosphere, mostly in the form of carbon dioxide. Carbon is by no means the only element whose natural cycle we have disturbed: we are transferring significant quantities of elements including phosphorus, sulfur, copper, and platinum from natural sinks or ores built up over millions of years to unnatural fates in the form of what we refer to as waste or pollution. However, our complete dependence on the carbon cycle means that its disturbance deserves special attention, as is now manifest in indicators such as climate change and escalating public concern over global warming. As with all disturbances in materials balances, we can seek to alleviate the problem by (1) dematerialization: a reduction in consumption; (2) rematerialization: a change in what we consume; or (3) transmaterialization: changing our attitude towards resources and waste. The "low-carbon" mantra that is popularly cited by organizations ranging from nongovernmental organizations to multinational companies and from local authorities to national governments is based on a combination of (1) and (2) (reducing carbon consumption though greater efficiency and lower per capita consumption, and replacing fossil energy sources with sources such as wind, wave, and solar, respectively). "Low carbon" is of inherently less value to the chemical and plastics industries at least in terms of raw materials although a version of (2), the use of biomass, does apply, especially if we use carbon sources that are renewable on a human timescale. There is however, another renewable, natural source of carbon that is widely available and for which greater utilization would help restore material balance and the natural cycle for carbon in terms of resource and waste. CO(2), perhaps the most widely discussed and feared chemical in modern society, is as fundamental to our survival as water, and like water we need to better understand the human as well as natural production and consumption of CO(2) so that we can attempt to get these into a sustainable balance. Current utilization of this valuable resource by the chemical industry is only 90 megatonne per year, compared to the 26.3 gigatonne CO(2) generated annually by combustion of fossil fuels for energy generation, as such significant opportunities exist for increased utilization of CO(2) generated from industrial processes. It is also essential that renewable energy is used if CO(2) is to be utilized as a C1 building block.

[Rhizosphere microbial impacts of alleviating faba bean Fusarium wilt with inoculating AM fungi].

PubMed

Dong, Yan; Dong, Kun; Yang, Zhi Xian; Tang, Li; Zheng, Yi

2016-12-01

Greenhouse pot trials were conducted to investigate the effects of arbuscular mycorrhizal fungus (Glomus mosseae, Glomus tortuosum, Glomus intraradices and Glomus etunicatum) inoculation on the seedling growth, occurance of Fusarium wilt, population of Fusarium oxysporum and rhizosphere microbial community functional diversity in faba bean rhizosphere soil. Results showed that after inoculation of G. mosseae, G. tortuosum, G. intraradices and G. etunicatum, the shoot and root fresh mass of faba bean seedlings increased significantly, the disease index of faba bean fusarium wilt decreased significantly by 94.0%, 60.0%, 64.0% and 94.0%, respectively, the amount of F. oxysporum of faba bean rhizosphere decreased significantly by 98.6%, 74.3%, 77.8% and 90.4%, respectively. The best inhibitory effects to Fusarium wilt were with G. mosseae and G. etunicatum treatments. Inoculation of G. mosseae, G. tortuosum and G. etunicatum significantly increased carbon sources utilization ability of carbohydrates, amino acids, carboxylic acids and phenolic acids, with the average well color development (AWCD) value being increased by 34.4%, 31.5% and 50.8% respectively, but such significant differences were not observed with inoculation of G. intraradice. Principal component analyses showed that inoculation of G. mosseae, G. tortuosum and G. etunicatum fungi changed the rhizospheric microbial community composition. Correlation analyses showed that the utilization of carbohydrates carbon sources (β-Methyl-D-glucoside, D-Galacturonic acid, D-Mannitol, N-Acetyl-D-Glucosamine, D-Cellobiose,) and carboxylic acids carbon sources (D-Galactonic acid-γ-Lactone) were significantly increased after inoculation of G. tortuosum, and the utilization of L-Arginine and 4-Hydroxy benzoic acid significantly increased after inoculation of G. mosseae and G. etunicatum. Carbohydrates, carboxylic acids were main carbon sources utilized by rhizosphere microbes after G. tortuosum and G. intraradices inoculation, and amino acids and phenolic acids were main carbon sources utilized by rhizosphere microbes after G. mosseae and G. etunicatum inoculation. Inoculation of AM fungi significantly increased the activities of rhizosphere microbes, changed soil microbe community functional diversity, and thus inhibited the growth of F. oxysporum. The inhibitory impacts of AM fungi inoculations depended on the changes of microbes utilizing carbon sources.

Increased cardiac output elicits higher V̇O2max in response to self-paced exercise.

PubMed

Astorino, Todd Anthony; McMillan, David William; Edmunds, Ross Montgomery; Sanchez, Eduardo

2015-03-01

Recently, a self-paced protocol demonstrated higher maximal oxygen uptake versus the traditional ramp protocol. The primary aim of the current study was to further explore potential differences in maximal oxygen uptake between the ramp and self-paced protocols using simultaneous measurement of cardiac output. Active men and women of various fitness levels (N = 30, mean age = 26.0 ± 5.0 years) completed 3 graded exercise tests separated by a minimum of 48 h. Participants initially completed progressive ramp exercise to exhaustion to determine maximal oxygen uptake followed by a verification test to confirm maximal oxygen uptake attainment. Over the next 2 sessions, they performed a self-paced and an additional ramp protocol. During exercise, gas exchange data were obtained using indirect calorimetry, and thoracic impedance was utilized to estimate hemodynamic function (stroke volume and cardiac output). One-way ANOVA with repeated measures was used to determine differences in maximal oxygen uptake and cardiac output between ramp and self-paced testing. Results demonstrated lower (p < 0.001) maximal oxygen uptake via the ramp (47.2 ± 10.2 mL·kg(-1)·min(-1)) versus the self-paced (50.2 ± 9.6 mL·kg(-1)·min(-1)) protocol, with no interaction (p = 0.06) seen for fitness level. Maximal heart rate and cardiac output (p = 0.02) were higher in the self-paced protocol versus ramp exercise. In conclusion, data show that the traditional ramp protocol may underestimate maximal oxygen uptake compared with a newly developed self-paced protocol, with a greater cardiac output potentially responsible for this outcome.

Renal Perfusion in Scleroderma Patients Assessed by Microbubble-Based Contrast-Enhanced Ultrasound

PubMed Central

Kleinert, Stefan; Roll, Petra; Baumgaertner, Christian; Himsel, Andrea; Mueller, Adelheid; Fleck, Martin; Feuchtenberger, Martin; Jenett, Manfred; Tony, Hans-Peter

2012-01-01

Objectives: Renal damage is common in scleroderma. It can occur acutely or chronically. Renal reserve might already be impaired before it can be detected by laboratory findings. Microbubble-based contrast-enhanced ultrasound has been demonstrated to improve blood perfusion imaging in organs. Therefore, we conducted a study to assess renal perfusion in scleroderma patients utilizing this novel technique. Materials and Methodology: Microbubble-based contrast agent was infused and destroyed by using high mechanical index by Siemens Sequoia (curved array, 4.5 MHz). Replenishment was recorded for 8 seconds. Regions of interests (ROI) were analyzed in renal parenchyma, interlobular artery and renal pyramid with quantitative contrast software (CUSQ 1.4, Siemens Acuson, Mountain View, California). Time to maximal Enhancement (TmE), maximal enhancement (mE) and maximal enhancement relative to maximal enhancement of the interlobular artery (mE%A) were calculated for different ROIs. Results: There was a linear correlation between the time to maximal enhancement in the parenchyma and the glomerular filtration rate. However, the other parameters did not reveal significant differences between scleroderma patients and healthy controls. Conclusion: Renal perfusion of scleroderma patients including the glomerular filtration rate can be assessed using microbubble-based contrast media. PMID:22670165

Lightweight, High Performance, Low Cost Propulsion Systems for Mars Exploration Missions to Maximize Science Payload

NASA Astrophysics Data System (ADS)

Trinh, H. P.

2012-06-01

Utilization of new cold hypergolic propellants and leverage Missile Defense Agency technology for propulsion systems on Mars explorations will provide an increase of science payload and have significant payoffs and benefits for NASA missions.

Genetic variation in the USDA Chamaecrista fasciculata collection

USDA-ARS?s Scientific Manuscript database

Germplasm collections serve as critical repositories of genetic variation. Characterizing genetic diversity in existing collections is necessary to maximize their utility and to guide future collecting efforts. We have used AFLP markers to characterize genetic variation in the USDA germplasm collect...

Utilization of corn cob biochar in a direct carbon fuel cell

NASA Astrophysics Data System (ADS)

Yu, Jinshuai; Zhao, Yicheng; Li, Yongdan

2014-12-01

Biochar obtained from the pyrolysis of corn cob is used as the fuel of a direct carbon fuel cell (DCFC) employing a composite electrolyte composed of a samarium doped ceria (SDC) and a eutectic carbonate phase. An anode layer made of NiO and SDC is utilized to suppress the cathode corrosion by the molten carbonate and improves the whole cell stability. The anode off-gas of the fuel cell is analyzed with a gas chromatograph. The effect of working temperature on the cell resistance and power output is examined. The maximum power output achieves 185 mW cm-2 at a current density of 340 mA cm-2 and 750 °C. An anode reaction scheme including the Boudouard reaction is proposed.

Porosity control in nanoporous carbide-derived carbon by oxidation in air and carbon dioxide

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

Osswald, S.; Portet, C.; Gogotsi, Y., E-mail: gogotsi@drexel.ed

2009-07-15

Carbide-derived carbons (CDC) allow a precise control over the pore size through the selection of the carbide precursor and varying of the synthesis conditions. However, their pore volume is limited by the carbide stoichiometry. While activation of carbons derived from various organic precursors has been widely studied, this process may similarly be able to increase the pore volume and specific surface area of CDC. Oxidation of carbide-derived carbon in air and CO{sub 2} at different temperatures and times allows for significant increase in pore volume and specific surface area as well as control over average pore size with subnanometer accuracy.more » The effect of activation and associated changes in the pore volume and surface area on the hydrogen uptake are also discussed. - Graphical abstract: Carbide-derived carbons (CDC) provide great potential for sorption of toxicants and gas storage applications. Activation of CDC in air and CO{sub 2} at different temperatures and times is applied in order to maximize pore volume and specific surface area, and control the average pore size with subnanometer accuracy.« less

Carbon translocation from symbiont to host depends on irradiance and food availability in the tropical coral Stylophora pistillata

NASA Astrophysics Data System (ADS)

Tremblay, P.; Grover, R.; Maguer, J. F.; Hoogenboom, M.; Ferrier-Pagès, C.

2014-03-01

Reef-building corals live in symbiosis with dinoflagellates that translocate a large proportion of their photosynthetically fixed carbon compounds to their coral host for its own metabolism. The carbon budget and translocation rate, however, vary depending on environmental conditions, coral host species, and symbiont clade. To quantify variability in carbon translocation in response to environmental conditions, this study assessed the effect of two different irradiance levels (120 and 250 μmol photons m-2 s-1) and feeding regimes (fed with Artemia salina nauplii and unfed) on the carbon budget of the tropical coral Stylophora pistillata. For this purpose, H13CO3 --enriched seawater was used to trace the conversion of photosynthetic carbon into symbiont and coral biomass and excrete particulate organic carbon. Results showed that carbon translocation (ca. 78 %) and utilization were similar under both irradiance levels for unfed colonies. In contrast, carbon utilization by fed colonies was dependent on the growth irradiance. Under low irradiance, heterotrophy was accompanied by lower carbon translocation (71 %), higher host and symbiont biomass, and higher calcification rates. Under high irradiance, heterotrophy was accompanied by higher rates of photosynthesis, respiration, and carbon translocation (90 %) as well as higher host biomass. Hence, levels of resource sharing within coral-dinoflagellate symbioses depend critically on environmental conditions.

Selective Formation of Trimethylene Carbonate (TMC): Atmospheric Pressure Carbon Dioxide Utilization

PubMed Central

Buckley, Benjamin R; Patel, Anish P; Wijayantha, K G Upul

2015-01-01

Carbon dioxide utilisation (CDU) is currently gaining increased interest due to the abundance of CO2 and its possible application as a C1 building block. We herein report the first example of atmospheric pressure carbon dioxide incorporation into oxetane to selectively form trimethylene carbonate (TMC), which is a significant challenge as TMC is thermodynamically less favoured than its corresponding co-polymer. PMID:26213485

Selective Formation of Trimethylene Carbonate (TMC): Atmospheric Pressure Carbon Dioxide Utilization.

PubMed

Buckley, Benjamin R; Patel, Anish P; Wijayantha, K G Upul

2015-01-01

Carbon dioxide utilisation (CDU) is currently gaining increased interest due to the abundance of CO 2 and its possible application as a C 1 building block. We herein report the first example of atmospheric pressure carbon dioxide incorporation into oxetane to selectively form trimethylene carbonate (TMC), which is a significant challenge as TMC is thermodynamically less favoured than its corresponding co-polymer.

Carbon-On-Carbon Manufacturing

NASA Technical Reports Server (NTRS)

Mungas, Gregory S. (Inventor); Buchanan, Larry (Inventor); Banzon, Jr., Jose T. (Inventor)

2017-01-01

The presently disclosed technology relates to carbon-on-carbon (C/C) manufacturing techniques and the resulting C/C products. One aspect of the manufacturing techniques disclosed herein utilizes two distinct curing operations that occur at different times and/or using different temperatures. The resulting C/C products are substantially non-porous, even though the curing operation(s) substantially gasify a liquid carbon-entrained filler material that saturates a carbon fabric that makes up the C/C products.

HPLC studio: a novel software utility to perform HPLC chromatogram comparison for screening purposes.

PubMed

García, J B; Tormo, José R

2003-06-01

A new tool, HPLC Studio, was developed for the comparison of high-performance liquid chromatography (HPLC) chromatograms from microbial extracts. The new utility makes it possible to create a virtual chromatogram by mixing up to 20 individual chromatograms. The virtual chromatogram is the first step in establishing a ranking of the microbial fermentation conditions based on either the area or diversity of HPLC peaks. The utility was used to maximize the diversity of secondary metabolites tested from a microorganism and therefore increase the chances of finding new lead compounds in a drug discovery program.

Network approach for decision making under risk—How do we choose among probabilistic options with the same expected value?

PubMed Central

Chen, Yi-Shin

2018-01-01

Conventional decision theory suggests that under risk, people choose option(s) by maximizing the expected utility. However, theories deal ambiguously with different options that have the same expected utility. A network approach is proposed by introducing ‘goal’ and ‘time’ factors to reduce the ambiguity in strategies for calculating the time-dependent probability of reaching a goal. As such, a mathematical foundation that explains the irrational behavior of choosing an option with a lower expected utility is revealed, which could imply that humans possess rationality in foresight. PMID:29702665

Network approach for decision making under risk-How do we choose among probabilistic options with the same expected value?

PubMed

Pan, Wei; Chen, Yi-Shin

2018-01-01

Conventional decision theory suggests that under risk, people choose option(s) by maximizing the expected utility. However, theories deal ambiguously with different options that have the same expected utility. A network approach is proposed by introducing 'goal' and 'time' factors to reduce the ambiguity in strategies for calculating the time-dependent probability of reaching a goal. As such, a mathematical foundation that explains the irrational behavior of choosing an option with a lower expected utility is revealed, which could imply that humans possess rationality in foresight.

Method and system for controlling a gasification or partial oxidation process

DOEpatents

Rozelle, Peter L; Der, Victor K

2015-02-10

A method and system for controlling a fuel gasification system includes optimizing a conversion of solid components in the fuel to gaseous fuel components, controlling the flux of solids entrained in the product gas through equipment downstream of the gasifier, and maximizing the overall efficiencies of processes utilizing gasification. A combination of models, when utilized together, can be integrated with existing plant control systems and operating procedures and employed to develop new control systems and operating procedures. Such an approach is further applicable to gasification systems that utilize both dry feed and slurry feed.

Metabolome analysis-based design and engineering of a metabolic pathway in Corynebacterium glutamicum to match rates of simultaneous utilization of D-glucose and L-arabinose.

PubMed

Kawaguchi, Hideo; Yoshihara, Kumiko; Hara, Kiyotaka Y; Hasunuma, Tomohisa; Ogino, Chiaki; Kondo, Akihiko

2018-05-17

L-Arabinose is the second most abundant component of hemicellulose in lignocellulosic biomass, next to D-xylose. However, few microorganisms are capable of utilizing pentoses, and catabolic genes and operons enabling bacterial utilization of pentoses are typically subject to carbon catabolite repression by more-preferred carbon sources, such as D-glucose, leading to a preferential utilization of D-glucose over pentoses. In order to simultaneously utilize both D-glucose and L-arabinose at the same rate, a modified metabolic pathway was rationally designed based on metabolome analysis. Corynebacterium glutamicum ATCC 31831 utilized D-glucose and L-arabinose simultaneously at a low concentration (3.6 g/L each) but preferentially utilized D-glucose over L-arabinose at a high concentration (15 g/L each), although L-arabinose and D-glucose were consumed at comparable rates in the absence of the second carbon source. Metabolome analysis revealed that phosphofructokinase and pyruvate kinase were major bottlenecks for D-glucose and L-arabinose metabolism, respectively. Based on the results of metabolome analysis, a metabolic pathway was engineered by overexpressing pyruvate kinase in combination with deletion of araR, which encodes a repressor of L-arabinose uptake and catabolism. The recombinant strain utilized high concentrations of D-glucose and L-arabinose (15 g/L each) at the same consumption rate. During simultaneous utilization of both carbon sources at high concentrations, intracellular levels of phosphoenolpyruvate declined and acetyl-CoA levels increased significantly as compared with the wild-type strain that preferentially utilized D-glucose. These results suggest that overexpression of pyruvate kinase in the araR deletion strain increased the specific consumption rate of L-arabinose and that citrate synthase activity becomes a new bottleneck in the engineered pathway during the simultaneous utilization of D-glucose and L-arabinose. Metabolome analysis identified potential bottlenecks in D-glucose and L-arabinose metabolism and was then applied to the following rational metabolic engineering. Manipulation of only two genes enabled simultaneous utilization of D-glucose and L-arabinose at the same rate in metabolically engineered C. glutamicum. This is the first report of rational metabolic design and engineering for simultaneous hexose and pentose utilization without inactivating the phosphotransferase system.

Martian resource locations: Identification and optimization

NASA Astrophysics Data System (ADS)

Chamitoff, Gregory; James, George; Barker, Donald; Dershowitz, Adam

2005-04-01

The identification and utilization of in situ Martian natural resources is the key to enable cost-effective long-duration missions and permanent human settlements on Mars. This paper presents a powerful software tool for analyzing Martian data from all sources, and for optimizing mission site selection based on resource collocation. This program, called Planetary Resource Optimization and Mapping Tool (PROMT), provides a wide range of analysis and display functions that can be applied to raw data or imagery. Thresholds, contours, custom algorithms, and graphical editing are some of the various methods that can be used to process data. Output maps can be created to identify surface regions on Mars that meet any specific criteria. The use of this tool for analyzing data, generating maps, and collocating features is demonstrated using data from the Mars Global Surveyor and the Odyssey spacecraft. The overall mission design objective is to maximize a combination of scientific return and self-sufficiency based on utilization of local materials. Landing site optimization involves maximizing accessibility to collocated science and resource features within a given mission radius. Mission types are categorized according to duration, energy resources, and in situ resource utilization. Preliminary optimization results are shown for a number of mission scenarios.

Endogenous patient responses and the consistency principle in cost-effectiveness analysis.

PubMed

Liu, Liqun; Rettenmaier, Andrew J; Saving, Thomas R

2012-01-01

In addition to incurring direct treatment costs and generating direct health benefits that improve longevity and/or health-related quality of life, medical interventions often have further or "unrelated" financial and health impacts, raising the issue of what costs and effects should be included in calculating the cost-effectiveness ratio of an intervention. The "consistency principle" in medical cost-effectiveness analysis (CEA) requires that one include both the cost and the utility benefit of a change (in medical expenditures, consumption, or leisure) caused by an intervention or neither of them. By distinguishing between exogenous changes directly brought about by an intervention and endogenous patient responses to the exogenous changes, and within a lifetime utility maximization framework, this article addresses 2 questions related to the consistency principle: 1) how to choose among alternative internally consistent exclusion/inclusion rules, and 2) what to do with survival consumption costs and earnings. It finds that, for an endogenous change, excluding or including both the cost and the utility benefit of the change does not alter cost-effectiveness results. Further, in agreement with the consistency principle, welfare maximization implies that consumption costs and earnings during the extended life directly caused by an intervention should be included in CEA.

Comparison of cardiorespiratory variables in dorsally recumbent horses anesthetized with guaifenesin-ketamine-xylazine spontaneously breathing 50% or maximal oxygen concentrations.

PubMed

Karrasch, Nicole M; Hubbell, John A E; Aarnes, Turi K; Bednarski, Richard M; Lerche, Phillip

2015-04-01

This study compared cardiorespiratory variables in dorsally recumbent horses anesthetized with guaifenesin-ketamine-xylazine and spontaneously breathing 50% or maximal (> 90%) oxygen (O2) concentrations. Twelve healthy mares were randomly assigned to breathe 50% or maximal O2 concentrations. Horses were sedated with xylazine, induced to recumbency with ketamine-diazepam, and anesthesia was maintained with guaifenesin-ketamine-xylazine to effect. Heart rate, arterial blood pressures, respiratory rate, lithium dilution cardiac output (CO), inspired and expired O2 and carbon dioxide partial pressures, and tidal volume were measured. Arterial and mixed-venous blood samples were collected prior to sedation (baseline), during 30 minutes of anesthesia, 10 minutes after disconnection from O2, and 30 minutes after standing. Shunt fraction, O2 delivery, and alveolar-arterial O2 partial pressures difference [P(A-a)O2] were calculated. Recovery times were recorded. There were no significant differences between groups in cardiorespiratory parameters or in P(A-a)O2 at baseline or 30 minutes after standing. Oxygen partial pressure difference in the 50% group was significantly less than in the maximal O2 group during anesthesia.

Comparison of cardiorespiratory variables in dorsally recumbent horses anesthetized with guaifenesin-ketamine-xylazine spontaneously breathing 50% or maximal oxygen concentrations

PubMed Central

Karrasch, Nicole M.; Hubbell, John A.E.; Aarnes, Turi K.; Bednarski, Richard M.; Lerche, Phillip

2015-01-01

This study compared cardiorespiratory variables in dorsally recumbent horses anesthetized with guaifenesin-ketamine-xylazine and spontaneously breathing 50% or maximal (> 90%) oxygen (O2) concentrations. Twelve healthy mares were randomly assigned to breathe 50% or maximal O2 concentrations. Horses were sedated with xylazine, induced to recumbency with ketamine-diazepam, and anesthesia was maintained with guaifenesin-ketamine-xylazine to effect. Heart rate, arterial blood pressures, respiratory rate, lithium dilution cardiac output (CO), inspired and expired O2 and carbon dioxide partial pressures, and tidal volume were measured. Arterial and mixed-venous blood samples were collected prior to sedation (baseline), during 30 minutes of anesthesia, 10 minutes after disconnection from O2, and 30 minutes after standing. Shunt fraction, O2 delivery, and alveolar-arterial O2 partial pressures difference [P(A-a)O2] were calculated. Recovery times were recorded. There were no significant differences between groups in cardiorespiratory parameters or in P(A-a)O2 at baseline or 30 minutes after standing. Oxygen partial pressure difference in the 50% group was significantly less than in the maximal O2 group during anesthesia. PMID:25829559

METHODOLOGIES FOR QUANTIFYING POLLUTION PREVENTION BENEFITS FROM LANDFILL GAS CONTROL AND UTILIZATION

EPA Science Inventory

The report describes developing emission factors for controlled primary pollutants (e.g., nonmethane organic compounds) and secondary air pollutants (e.g., carbon monoxide). The report addresses the following criteria air pollutants and greenhouse gases: carbon dioxide, carbon mo...

Effects of lithium carbonate on performance and biomedical functions.

DOT National Transportation Integrated Search

1977-07-01

The effects of a single 600-mg dose of lithium carbonate were evaluated in a study of 15 healthy, normal male subjects. Subjects were studied, on two occasions, by utilizing a double-blind design--once receiving the lithium carbonate and once receivi...

Strategies Needed to Maximize Industry Support for Breeding of Energy Cane as a Biomass Feedstock for Coal and other Co-Products

USDA-ARS?s Scientific Manuscript database

Research and advanced breeding have demonstrated that energy cane possesses all of the attributes desirable in a biofuel feedstock: extremely good biomass yield in a small farming footprint; negative/neutral carbon footprint; maximum outputs from minimum inputs; well-established growing model for fa...

A cyber-enabled spatial decision support system to inventory Mangroves in Mozambique: coupling scientific workflows and cloud computing

Treesearch

Wenwu Tang; Wenpeng Feng; Meijuan Jia; Jiyang Shi; Huifang Zuo; Christina E. Stringer; Carl C. Trettin

2017-01-01

Mangroves are an important terrestrial carbon reservoir with numerous ecosystem services. Yet, it is difficult to inventory mangroves because of their low accessibility. A sampling approach that produces accurate assessment while maximizing logistical integrity of inventory operation is often required. Spatial decision support systems (SDSSs) provide support for...

Fine-scale variability in growth-climate relationships of Douglas-fir, North Cascade Range, Washington.

Treesearch

Michael J. Case; David L. Peterson

2005-01-01

Information about the sensitivity to climate of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is valuable because it will allow forest managers to maximize growth, better understand how carbon sequestration may change over time, and better model and predict future ecosystem responses to climatic change. We examined the effects of climatic...

Spatial distribution of ammonium and calcium in optimally fertilized pine plantation soils

Treesearch

Ivan Edwards; Andrew Gillespie; Jennifer Chen; Kurt Johnsen; Ronald Turco

2005-01-01

Commercial timber production is increasingly reliant on long-term fertilization to maximize stand productivity, yet we do not understand the extent to which this practice homogenizes soil properties. The effects of 16 yr of optimal fertilization and optimal fertilization with irrigation (fertigation) on forest floor depth, pH, total organic carbon (TOC) and total...

Leaf and canopy scale drivers of genotypic variation in soybean response to elevated carbon dioxide concentration

USDA-ARS?s Scientific Manuscript database

The atmospheric [CO2] in which crops grow today is greater than at any point in their domestication history, and represents an opportunity for positive effects on seed yield that can counteract the negative effects of greater heat and drought this century. In order to maximize yields under future at...

Environmental technologies of woody crop production systems

Treesearch

Ronald S. Zalesny Jr.; John A. Stanturf; Emile S. Gardiner; Gary S. Ba??uelos; Richard A. Hallett; Amir Hass; Craig M. Stange; James H. Perdue; Timothy M. Young; David R. Coyle; William L. Headlee

2016-01-01

Soil erosion, loss of productivity potential, biodiversity loss, water shortage, and soil and water pollution are ongoing processes that decrease or degrade provisioning (e.g., biomass, freshwater) and regulating (e.g., carbon sequestration, soil quality) ecosystem services. Therefore, developing environmental technologies that maximize these services is essential for...

Thermodynamic Simulation of Carbonate Cements-Water-Carbon Dioxide Equilibrium in Sandstone for Prediction of Precipitation/Dissolution of Carbonate Cements

PubMed Central

Zhong, Xinyan; Shang, Ruishu; Huang, Lihong

2016-01-01

Carbonate cements, such as calcite, dolomite, ferrocalcite and ankerite, play important roles in the formation of pores in sandstones: precipitation of carbonate cements modifies pores and inhibits compaction, while dissolution creates secondary pores. This work proposed a precipitation-dissolution model for carbonate cements-CO2-H2O system by means of ion equilibrium concentration ([M2+], M = Ca, Mg, Fe or Mn) with different factors, such as temperature, depth, pH, PCO2, variable rock composition and overpressure. Precipitation-dissolution reaction routes were also analyzed by minimization of the total Gibbs free energy (ΔG). Δ[M2+], the variation of [Ca2+], [Fe2+], [Mg2+] or [Mn2+] for every 100 m of burial depths, is used to predict precipitation or dissolution. The calculation results indicate that the increasing temperature results in decrease of equilibrium constant of reactions, while the increasing pressure results in a relatively smaller increase of equilibrium constant; As a result, with increasing burial depth, which brings about increase of both temperature and pressure, carbonate cements dissolve firstly and produces the maximal dissolved amounts, and then precipitation happens with further increasing depth; For example, calcite is dissolving from 0.0 km to 3.0 km with a maximal value of [Ca2+] at depth of 0.8 km, and then precipitates with depth deeper than 3.0 km. Meanwhile, with an increasing CO2 mole fraction in the gaseous phase from 0.1% to 10.0% in carbonate systems, the aqueous concentration of metal ions increases, e.g., dissolved amount of CaFe0.7Mg0.3(CO3)2 increases and reaches maximum of 1.78 mmol·L-1 and 8.26 mmol·L-1 at burial depth of 0.7 km with CO2 mole fraction of 0.1% and 10.0%, respectively. For the influence of overpressure in the calcite system, with overpressure ranging from 36 MPa to 83 MPa, pH reaches a minimum of 6.8 at overpressure of 51 MPa; meanwhile, Δ[Ca2+] increases slightly from -2.24 mmol·L-1 to -2.17 mmol·L-1 and remains negative, indicating it is also a precipitation process at burial depth of 3.9 km where overpressure generated. The method used in this study can be applied in assessing burial precipitation-dissolution processes and predicting possible pores in reservoirs with carbonate cement-water-carbon dioxide. PMID:27907043

Thermodynamic Simulation of Carbonate Cements-Water-Carbon Dioxide Equilibrium in Sandstone for Prediction of Precipitation/Dissolution of Carbonate Cements.

PubMed

Duan, Yiping; Feng, Mingshi; Zhong, Xinyan; Shang, Ruishu; Huang, Lihong

2016-01-01

Carbonate cements, such as calcite, dolomite, ferrocalcite and ankerite, play important roles in the formation of pores in sandstones: precipitation of carbonate cements modifies pores and inhibits compaction, while dissolution creates secondary pores. This work proposed a precipitation-dissolution model for carbonate cements-CO2-H2O system by means of ion equilibrium concentration ([M2+], M = Ca, Mg, Fe or Mn) with different factors, such as temperature, depth, pH, [Formula: see text], variable rock composition and overpressure. Precipitation-dissolution reaction routes were also analyzed by minimization of the total Gibbs free energy (ΔG). Δ[M2+], the variation of [Ca2+], [Fe2+], [Mg2+] or [Mn2+] for every 100 m of burial depths, is used to predict precipitation or dissolution. The calculation results indicate that the increasing temperature results in decrease of equilibrium constant of reactions, while the increasing pressure results in a relatively smaller increase of equilibrium constant; As a result, with increasing burial depth, which brings about increase of both temperature and pressure, carbonate cements dissolve firstly and produces the maximal dissolved amounts, and then precipitation happens with further increasing depth; For example, calcite is dissolving from 0.0 km to 3.0 km with a maximal value of [Ca2+] at depth of 0.8 km, and then precipitates with depth deeper than 3.0 km. Meanwhile, with an increasing CO2 mole fraction in the gaseous phase from 0.1% to 10.0% in carbonate systems, the aqueous concentration of metal ions increases, e.g., dissolved amount of CaFe0.7Mg0.3(CO3)2 increases and reaches maximum of 1.78 mmol·L-1 and 8.26 mmol·L-1 at burial depth of 0.7 km with CO2 mole fraction of 0.1% and 10.0%, respectively. For the influence of overpressure in the calcite system, with overpressure ranging from 36 MPa to 83 MPa, pH reaches a minimum of 6.8 at overpressure of 51 MPa; meanwhile, Δ[Ca2+] increases slightly from -2.24 mmol·L-1 to -2.17 mmol·L-1 and remains negative, indicating it is also a precipitation process at burial depth of 3.9 km where overpressure generated. The method used in this study can be applied in assessing burial precipitation-dissolution processes and predicting possible pores in reservoirs with carbonate cement-water-carbon dioxide.

Carbon isotope fractionation during microbial methane oxidation

NASA Astrophysics Data System (ADS)

Barker, James F.; Fritz, Peter

1981-09-01

Methane, a common trace constituent of groundwaters, occasionally makes up more than 20% of the total carbon in groundwaters1,2. In aerobic environments CH4-rich waters can enable microbial food chain supporting a mixed culture of bacteria with methane oxidation as the primary energy source to develop3. Such processes may influence the isotopic composition of the residual methane and because 13C/12C analyses have been used to characterize the genesis of methanes found in different environments, an understanding of the magnitude of such effects is necessary. In addition, carbon dioxide produced by the methane-utilizing bacteria can be added to the inorganic carbon pool of affected groundwaters. We found carbon dioxide experimentally produced by methane-utilizing bacteria to be enriched in 12C by 5.0-29.6‰, relative to the residual methane. Where methane-bearing groundwaters discharged into aerobic environments microbial methane oxidation occurred, with the residual methane becoming progressively enriched in 13C. Various models have been proposed to explain the 13C/12C and 14C content of the dissolved inorganic carbon (DIC) of groundwaters in terms of additions or losses during flow in the subsurface4,5. The knowledge of both stable carbon isotope ratios in various pools and the magnitude of carbon isotope fractionation during various processes allows geochemists to use the 13C/12C ratio of the DIC along with water chemistry to estimate corrected 14C groundwater ages4,5. We show here that a knowledge of the carbon isotope fractionation between CH4 and CO2 during microbial methane-utilization could modify such models for application to groundwaters affected by microbial methane oxidation.

Comparing (Semi-) Analytic Solutions Used to Model the Impact of Deep Carbon Injection on the Displacement and Pressurization of the Resident Brine

EPA Science Inventory

Injection of carbon dioxide into deep saline formations is seen as one possible technology for mitigating carbon emissions from utilities. The safety of the sequestered carbon dioxide is the focus of many studies with leakage through faults or abandoned wells as some of the main...

Statistical characterization of carbon phenolic prepreg materials, volume 1

NASA Technical Reports Server (NTRS)

Beckley, Don A.; Stites, John, Jr.

1988-01-01

The objective was to characterize several lots of materials used for carbon/carbon and carbon/phenol product manufacture. Volume one is organized into testing categories based on raw material of product form. Each category contains a discussion of the sampling plan, comments and observations on each test method utilized, and a summary of the results obtained each category.

Effects of Inulin and Sodium Carbonate in Phosphate-Free Restructured Poultry Steaks

NASA Astrophysics Data System (ADS)

Öztürk, B.; Serdaroğlu, M.

2017-09-01

Recently inorganic phosphates used in meat product formulations have caused negative impact on consumers due to their potential health risks. Therefore, utilization of natural ingredients as phosphate replacers has come into prominence as a novel research topic to meet consumer demands for clean-label trends. In this study, we objected to investigate the effects of inulin utilization either in the powder or gelled form, alone or in combination with sodium carbonate on quality of phosphate-free restructured chicken steaks. Total moisture, protein, lipid and ash values of the trial groups were in the range of 71.54-75.46%, 22.60-24.31%, 0.94-1.70% and 1.45-2.13%, respectively. pH of the samples was between 6.18-6.39, significant increments were recorded in samples containing inulin with sodium carbonate. L*, a* and b* values were recorded as 78.92-81.05, 1.76-3.05 and 10.80-11.94, respectively, where use of gelled inulin resulted in changes of L* and a* values. Utilization of inulin in combination with sodium carbonate decreased cook loss and enhanced product yield. Sensory scores in control group with phosphate showed a similar pattern to sensory scores in groups with inulin and sodium carbonate. During storage, purge loss and lipid oxidation rate were similar in control and inulin + sodium carbonate samples. The results showed that use of inulin in combination with sodium carbonate provided equivalent physical, chemical and sensory quality to phosphates in restructured chicken steaks.

An auxiliary graph based dynamic traffic grooming algorithm in spatial division multiplexing enabled elastic optical networks with multi-core fibers

NASA Astrophysics Data System (ADS)

Zhao, Yongli; Tian, Rui; Yu, Xiaosong; Zhang, Jiawei; Zhang, Jie

2017-03-01

A proper traffic grooming strategy in dynamic optical networks can improve the utilization of bandwidth resources. An auxiliary graph (AG) is designed to solve the traffic grooming problem under a dynamic traffic scenario in spatial division multiplexing enabled elastic optical networks (SDM-EON) with multi-core fibers. Five traffic grooming policies achieved by adjusting the edge weights of an AG are proposed and evaluated through simulation: maximal electrical grooming (MEG), maximal optical grooming (MOG), maximal SDM grooming (MSG), minimize virtual hops (MVH), and minimize physical hops (MPH). Numeric results show that each traffic grooming policy has its own features. Among different traffic grooming policies, an MPH policy can achieve the lowest bandwidth blocking ratio, MEG can save the most transponders, and MSG can obtain the fewest cores for each request.

Feasibility Study of Coal Gasification/Fuel Cell/Cogeneration Project. Scranton, Pennsylvania Site. Project Description,

DTIC Science & Technology

1985-11-01

arranged to maximize thermal output; - Plant will meet PURPA criteria for recognition as a "Qualifying Facility" (QF). 7587A 2 - GFC emissions will be...10. Plant must meet Public Utilities Regulatory Policies Act ( PURPA ) criteria for classification as a "Qualifying Facility" (QF). 11. Visual effect...assessments. 3 The Public Utilities Regulatory Policies Act ( PURPA ) which is administered by the Federal Energy Regulatory Commission (FERC), governs how a

Global Snow from Space: Development of a Satellite-based, Terrestrial Snow Mission Planning Tool

NASA Astrophysics Data System (ADS)

Forman, B. A.; Kumar, S.; LeMoigne, J.; Nag, S.

2017-12-01

A global, satellite-based, terrestrial snow mission planning tool is proposed to help inform experimental mission design with relevance to snow depth and snow water equivalent (SWE). The idea leverages the capabilities of NASA's Land Information System (LIS) and the Tradespace Analysis Tool for Constellations (TAT-C) to harness the information content of Earth science mission data across a suite of hypothetical sensor designs, orbital configurations, data assimilation algorithms, and optimization and uncertainty techniques, including cost estimates and risk assessments of each hypothetical permutation. One objective of the proposed observing system simulation experiment (OSSE) is to assess the complementary - or perhaps contradictory - information content derived from the simultaneous collection of passive microwave (radiometer), active microwave (radar), and LIDAR observations from space-based platforms. The integrated system will enable a true end-to-end OSSE that can help quantify the value of observations based on their utility towards both scientific research and applications as well as to better guide future mission design. Science and mission planning questions addressed as part of this concept include: What observational records are needed (in space and time) to maximize terrestrial snow experimental utility? How might observations be coordinated (in space and time) to maximize this utility? What is the additional utility associated with an additional observation? How can future mission costs be minimized while ensuring Science requirements are fulfilled?

Towards the Development of a Global, Satellite-based, Terrestrial Snow Mission Planning Tool

NASA Technical Reports Server (NTRS)

Forman, Bart; Kumar, Sujay; Le Moigne, Jacqueline; Nag, Sreeja

2017-01-01

A global, satellite-based, terrestrial snow mission planning tool is proposed to help inform experimental mission design with relevance to snow depth and snow water equivalent (SWE). The idea leverages the capabilities of NASAs Land Information System (LIS) and the Tradespace Analysis Tool for Constellations (TAT C) to harness the information content of Earth science mission data across a suite of hypothetical sensor designs, orbital configurations, data assimilation algorithms, and optimization and uncertainty techniques, including cost estimates and risk assessments of each hypothetical orbital configuration.One objective the proposed observing system simulation experiment (OSSE) is to assess the complementary or perhaps contradictory information content derived from the simultaneous collection of passive microwave (radiometer), active microwave (radar), and LIDAR observations from space-based platforms. The integrated system will enable a true end-to-end OSSE that can help quantify the value of observations based on their utility towards both scientific research and applications as well as to better guide future mission design. Science and mission planning questions addressed as part of this concept include:1. What observational records are needed (in space and time) to maximize terrestrial snow experimental utility?2. How might observations be coordinated (in space and time) to maximize utility? 3. What is the additional utility associated with an additional observation?4. How can future mission costs being minimized while ensuring Science requirements are fulfilled?

Towards the Development of a Global, Satellite-Based, Terrestrial Snow Mission Planning Tool

NASA Technical Reports Server (NTRS)

Forman, Bart; Kumar, Sujay; Le Moigne, Jacqueline; Nag, Sreeja

2017-01-01

A global, satellite-based, terrestrial snow mission planning tool is proposed to help inform experimental mission design with relevance to snow depth and snow water equivalent (SWE). The idea leverages the capabilities of NASA's Land Information System (LIS) and the Tradespace Analysis Tool for Constellations (TAT-C) to harness the information content of Earth science mission data across a suite of hypothetical sensor designs, orbital configurations, data assimilation algorithms, and optimization and uncertainty techniques, including cost estimates and risk assessments of each hypothetical permutation. One objective of the proposed observing system simulation experiment (OSSE) is to assess the complementary or perhaps contradictory information content derived from the simultaneous collection of passive microwave (radiometer), active microwave (radar), and LIDAR observations from space-based platforms. The integrated system will enable a true end-to-end OSSE that can help quantify the value of observations based on their utility towards both scientific research and applications as well as to better guide future mission design. Science and mission planning questions addressed as part of this concept include: What observational records are needed (in space and time) to maximize terrestrial snow experimental utility? How might observations be coordinated (in space and time) to maximize this utility? What is the additional utility associated with an additional observation? How can future mission costs be minimized while ensuring Science requirements are fulfilled?

Impact of Private Health Insurance on Lengths of Hospitalization and Healthcare Expenditure in India: Evidences from a Quasi-Experiment Study.

PubMed

Vellakkal, Sukumar

2013-01-01

The health insurers administer retrospectively package rates for various inpatient procedures as a provider payment mechanism to empanelled hospitals in Indian healthcare market. This study analyzed the impact of private health insurance on healthcare utilization in terms of both lengths of hospitalization and per-day hospitalization expenditure in Indian healthcare market where package rates are retrospectively defined as healthcare provider payment mechanism. The claim records of 94443 insured individuals and the hospitalisation data of 32665 uninsured individuals were used. By applying stepwise and propensity score matching method, the sample of uninsured individual was matched with insured and 'average treatment effect on treated' (ATT) was estimated. Overall, the strategies of hospitals, insured and insurers for maximizing their utility were competing with each other. However, two aligning co-operative strategies between insurer and hospitals were significant with dominant role of hospitals. The hospitals maximize their utility by providing high cost healthcare in par with pre-defined package rates but align with the interest of insurers by reducing the number (length) of hospitalisation days. The empirical results show that private health insurance coverage leads to i) reduction in length of hospitalization, and ii) increase in per day hospital (health) expenditure. It is necessary to regulate and develop a competent healthcare market in the country with proper monitoring mechanism on healthcare utilization and benchmarks for pricing and provision of healthcare services.

[Effect of multi-walled carbon nanotubes on the morphofunctional state of the small intestine cells of mice].

PubMed

Beliaeva, N N; Mikhaĭlova, R I; Sycheva, L P; Savostikova, O N; Zelenkina, E A; Gasimova, Z M; Alekseeva, A V; Ryzhova, I N; Altaeva, A A

2012-01-01

The experiment was conducted in male mice SBAchS57Vl/6 and Balb/c, which consumed water, obtained from the use of carbon nanotubes. in a free drinking regimen for 2 weeks (mice SBAchS57Vl/6) and 2 months (mice Balb/c) Control group consisted of three groups of animals: intact and mice received fine coal in the same concentrations as under the impact of the nanotubes. Under exposure to the maximal of the studied concentration of carbon nanotubes a significant change in the fine structure of the villi of the small intestine was found in the form of increasing the number of unstructured villi and proliferation of epithelial cells, most pronounced in duration of exposure until 2 months.

"Cold" synthesis of carbon from polyvinyl chloride with the use of an electron beam ejected into the atmosphere

NASA Astrophysics Data System (ADS)

Kryazhev, Yu. G.; Vorob'ev, M. S.; Koval', N. N.; Trenikhin, M. V.; Solodovnichenko, V. S.; Sulakshin, S. A.; Likholobov, V. A.

2016-10-01

This work shows the possibility in principle of forming hydrocarbon structures in polyvinyl chloride films free of admixtures and polyvinyl chloride films modified with 5-mass % ferrocene via a radiation chemical transformation in the atmosphere with the use of an electron accelerator with a plasma cathode operating in the pulsed-periodic mode maximal electron energy no higher than 160 keV, pulse length of 40 μs, and current density of 5 mA/cm2. According to the results of semiquantitative X-ray microanalysis, an irradiated polyvinyl chloride film free of admixtures contains 92 of carbon, 6 of oxygen, and 2 mass % of chlorine; the irradiated polyvinyl chloride is an amorphous carbon material. A possible mechanism of the phenomenon is discussed.

Can portable pyrolysis units make biomass utilization affordable while using bio-char to enhance soil productivity and sequester carbon?

Treesearch

Mark Coleman; Deborah Page-Dumroese; Jim Archuleta; Phil Badger; Woodum Chung; Tyron Venn; Dan Loeffler; Greg Jones; Kristin McElligott

2010-01-01

We describe a portable pyrolysis system for bioenergy production from forest biomass that minimizes long-distance transport costs and provides for nutrient return and long-term soil carbon storage. The cost for transporting biomass to conversion facilities is a major impediment to utilizing forest biomass. If forest biomass could be converted into bio-oil in the field...

Assessing methanotrophy and carbon fixation for biofuel production by Methanosarcina acetivorans

DOE PAGES

Nazem-Bokaee, Hadi; Gopalakrishnan, Saratram; Ferry, James G.; ...

2016-01-17

Methanosarcina acetivorans is a model archaeon with renewed interest due to its unique reversible methane production pathways. However, the mechanism and relevant pathways implicated in (co)utilizing novel carbon substrates in this organism are still not fully understood. This paper provides a comprehensive inventory of thermodynamically feasible routes for anaerobic methane oxidation, co-reactant utilization, and maximum carbon yields of major biofuel candidates by M. acetivorans. Here, an updated genome-scale metabolic model of M. acetivorans is introduced (iMAC868 containing 868 genes, 845 reactions, and 718 metabolites) by integrating information from two previously reconstructed metabolic models (i.e., iVS941 and iMB745), modifying 17 reactions,more » adding 24 new reactions, and revising 64 gene-proteinreaction associations based on newly available information. The new model establishes improved predictions of growth yields on native substrates and is capable of correctly predicting the knockout outcomes for 27 out of 28 gene deletion mutants. By tracing a bifurcated electron flow mechanism, the iMAC868 model predicts thermodynamically feasible (co)utilization pathway of methane and bicarbonate using various terminal electron acceptors through the reversal of the aceticlastic pathway. In conclusion, this effort paves the way in informing the search for thermodynamically feasible ways of (co)utilizing novel carbon substrates in the domain Archaea.« less

Environmental applications of HTC technology: Biochar production, carbon sequestration, and waste conversion

USDA-ARS?s Scientific Manuscript database

Motivations for the development and use of hydrothermal carbonization (or wet pyrolysis) have been primarily directed towards the sustainable creation of carbon nanomaterials/nanostructures for use in applications ranging from hydrogen storage to chemical adsorption. The utility of this process, how...

Effective Fund-Raising for Non-profit Camps.

ERIC Educational Resources Information Center

Larson, Paula

1998-01-01

Identifies and describes strategies for effective fundraising: imagining the possibilities, identifying fund-raising sources, targeting fund-raising efforts, maximizing time by utilizing public relations efforts and involving staff, writing quality proposals and requests, and staying educated on fund-raising topics. Sidebars describe planned…

RFC: EPA's Action Plan for Bisphenol A Pursuant to EPA's Data Quality Guidelines

EPA Pesticide Factsheets

The American Chemistry Council (ACC) submits this Request for Correction to the U.S. Environmental Protection Agency under the Guidelines for Ensuring and Maximizing the Quality, Objectivity, Utility, and Integrity of Information Disseminated by the Environmental Protection Agency

Maximizing Educational Opportunity through Community Resources.

ERIC Educational Resources Information Center

Maradian, Steve

In the face of increased demands and diminishing resources, educational administrators at correctional facilities should look beyond institutional resources and utilize the services of area community colleges. The community college has an established track record in correctional education. Besides the nationally recognized correctional programs…

Applying Intermediate Microeconomics to Terrorism

ERIC Educational Resources Information Center

Anderton, Charles H.; Carter, John R.

2006-01-01

The authors show how microeconomic concepts and principles are applicable to the study of terrorism. The utility maximization model provides insights into both terrorist resource allocation choices and government counterterrorism efforts, and basic game theory helps characterize the strategic interdependencies among terrorists and governments.…

Carbon and nutrient use efficiencies optimally balance stoichiometric imbalances

NASA Astrophysics Data System (ADS)

Manzoni, Stefano; Čapek, Petr; Lindahl, Björn; Mooshammer, Maria; Richter, Andreas; Šantrůčková, Hana

2016-04-01

Decomposer organisms face large stoichiometric imbalances because their food is generally poor in nutrients compared to the decomposer cellular composition. The presence of excess carbon (C) requires adaptations to utilize nutrients effectively while disposing of or investing excess C. As food composition changes, these adaptations lead to variable C- and nutrient-use efficiencies (defined as the ratios of C and nutrients used for growth over the amounts consumed). For organisms to be ecologically competitive, these changes in efficiencies with resource stoichiometry have to balance advantages and disadvantages in an optimal way. We hypothesize that efficiencies are varied so that community growth rate is optimized along stoichiometric gradients of their resources. Building from previous theories, we predict that maximum growth is achieved when C and nutrients are co-limiting, so that the maximum C-use efficiency is reached, and nutrient release is minimized. This optimality principle is expected to be applicable across terrestrial-aquatic borders, to various elements, and at different trophic levels. While the growth rate maximization hypothesis has been evaluated for consumers and predators, in this contribution we test it for terrestrial and aquatic decomposers degrading resources across wide stoichiometry gradients. The optimality hypothesis predicts constant efficiencies at low substrate C:N and C:P, whereas above a stoichiometric threshold, C-use efficiency declines and nitrogen- and phosphorus-use efficiencies increase up to one. Thus, high resource C:N and C:P lead to low C-use efficiency, but effective retention of nitrogen and phosphorus. Predictions are broadly consistent with efficiency trends in decomposer communities across terrestrial and aquatic ecosystems.

A photovoltaic catenary-tent array for the Martian surface

NASA Technical Reports Server (NTRS)

Crutchik, M.; Colozza, Anthony J.; Appelbaum, J.

1993-01-01

To provide electrical power during an exploration mission to Mars, a deployable tent-shaped structure with a flexible photovoltaic (PV) blanket is proposed. The array is designed with a self-deploying mechanism utilizing pressurized gas expansion. The structural design for the array uses a combination of cables, beams, and columns to support and deploy the PV blanket. Under the force of gravity a cable carrying a uniform load will take the shape of a catenary curve. A catenary-tent collector is self shadowing which must be taken into account in the solar radiation calculation. The shape and the area of the shadow on the array was calculated and used in the determination of the global radiation on the array. The PV blanket shape and structure dimension were optimized to achieve a configuration which maximizes the specific power (W/kg). The optimization was performed for four types of PV blankets (Si, GaAs/Ge, GaAs CLEFT, and amorphous Si) and four types of structure materials (Carbon composite, Aramid Fiber composite, Aluminum, and Magnesium). The results show that the catenary shape of the PV blanket, which produces the highest specific power, corresponds to zero end angle at the base with respect to the horizontal. The tent angle is determined by the combined effect of the array structure specific mass and the PV blanket output power. The combination of carbon composite structural material and GaAs CLEFT solar cells produce the highest specific power. The study was carried out for two sites on Mars corresponding to the Viking Lander locations. The designs were also compared for summer, winter, and yearly operation.

Carbon Nanotube-based microelectrodes for enhanced detection of neurotransmitters

NASA Astrophysics Data System (ADS)

Jacobs, Christopher B.

Fast-scan cyclic voltammetry (FSCV) is one of the common techniques used for rapid measurement of neurotransmitters in vivo. Carbon-fiber microelectrodes (CFMEs) are typically used for neurotransmitter detection because of sub-second measurement capabilities, ability to measure changes in neurotransmitter concentration during neurotransmission, and the small size electrode diameter, which limits the amount of damage caused to tissue. Cylinder CFMEs, typically 50 -- 100 microm long, are commonly used for in vivo experiments because the electrode sensitivity is directly related to the electrode surface area. However the length of the electrode can limit the spatial resolution of neurotransmitter detection, which can restrict experiments in Drosophila and other small model systems. In addition, the electrode sensitivity toward dopamine and serotonin detection drops significantly for measurements at rates faster than 10 Hz, limiting the temporal resolution of CFMEs. While the use of FSCV at carbon-fiber microelectrodes has led to substantial strides in our understanding of neurotransmission, techniques that expand the capabilities of CFMEs are crucial to fully maximize the potential uses of FSCV. This dissertation introduces new methods to integrate carbon nanotubes (CNT) into microelectrodes and discusses the electrochemical enhancements of these CNT-microelectrodes. The electrodes are specifically designed with simple fabrication procedures so that highly specialized equipment is not necessary, and they utilize commercially available materials so that the electrodes could be easily integrated into existing systems. The electrochemical properties of CNT modified CFMEs are characterized using FSCV and the effect of CNT functionalization on these properties is explored in Chapter 2. For example, CFME modification using carboxylic acid functionalized CNTs yield about a 6-fold increase in dopamine oxidation current, but modification with octadecylamine CNTs results in a negligible change to the signal. Chapter 3 is devoted to the development and characterization of new CNT-Yarn Microelectrodes (CNTYME) which display a beneficial enhancement in sensitivity and reduction in both electron transfer kinetics and overpotential. Chapter 4 introduces the high-speed dopamine detection capabilities of CNTYMEs, almost two orders of magnitude faster than at CFMEs without any compromise in electrochemical sensitivity, and discusses how adsorption and desorption relate to this phenomenon.

High electrochemical capacitor performance of oxygen and nitrogen enriched activated carbon derived from the pyrolysis and activation of squid gladius chitin

NASA Astrophysics Data System (ADS)

Raj, C. Justin; Rajesh, Murugesan; Manikandan, Ramu; Yu, Kook Hyun; Anusha, J. R.; Ahn, Jun Hwan; Kim, Dong-Won; Park, Sang Yeup; Kim, Byung Chul

2018-05-01

Activated carbon containing nitrogen functionalities exhibits excellent electrochemical property which is more interesting for several renewable energy storage and catalytic applications. Here, we report the synthesis of microporous oxygen and nitrogen doped activated carbon utilizing chitin from the gladius of squid fish. The activated carbon has large surface area of 1129 m2 g-1 with microporous network and possess ∼4.04% of nitrogen content in the form of pyridinic/pyrrolic-N, graphitic-N and N-oxide groups along with oxygen and carbon species. The microporous oxygen/nitrogen doped activated carbon is utilize for the fabrication of aqueous and flexible supercapacitor electrodes, which presents excellent electrochemical performance with maximum specific capacitance of 204 Fg-1 in 1 M H2SO4 electrolyte and 197 Fg-1 as a flexible supercapacitor. Moreover, the device displays 100% of specific capacitance retention after 25,000 subsequent charge/discharge cycles in 1 M H2SO4 electrolyte.

Treatment of aqueous phase of bio-oil by granular activated carbon and evaluation of biogas production.

PubMed

Shanmugam, Saravanan R; Adhikari, Sushil; Wang, Zhouhang; Shakya, Rajdeep

2017-01-01

Hydrothermal liquefaction of wet biomass such as algae is a promising thermochemical process for the production of bio-oil. Bio-oil aqueous phase generated during liquefaction process is rich in complex organics and can be utilized for biogas production following its pre-treatment with granular activated carbon. In our study, use of 30% activated carbon resulted in higher chemical oxygen demand (COD) reduction (53±0.3%) from aqueous phase. Higher CH 4 production (84±12mL/gCOD) was also observed in 30% carbon-treated aqueous phase fed cultures, whereas only 32±6mLCH 4 /gCOD was observed in control (non-carbon treated) cultures. The results from this study indicate that almost 67±0.3% initial COD of aqueous phase can be reduced using a combination of both carbon treatment and biogas production. This study shows that aqueous phase can be utilized for CH 4 production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Building carbon–carbon bonds using a biocatalytic methanol condensation cycle

PubMed Central

Bogorad, Igor W.; Chen, Chang-Ting; Theisen, Matthew K.; Wu, Tung-Yun; Schlenz, Alicia R.; Lam, Albert T.; Liao, James C.

2014-01-01

Methanol is an important intermediate in the utilization of natural gas for synthesizing other feedstock chemicals. Typically, chemical approaches for building C–C bonds from methanol require high temperature and pressure. Biological conversion of methanol to longer carbon chain compounds is feasible; however, the natural biological pathways for methanol utilization involve carbon dioxide loss or ATP expenditure. Here we demonstrated a biocatalytic pathway, termed the methanol condensation cycle (MCC), by combining the nonoxidative glycolysis with the ribulose monophosphate pathway to convert methanol to higher-chain alcohols or other acetyl-CoA derivatives using enzymatic reactions in a carbon-conserved and ATP-independent system. We investigated the robustness of MCC and identified operational regions. We confirmed that the pathway forms a catalytic cycle through 13C-carbon labeling. With a cell-free system, we demonstrated the conversion of methanol to ethanol or n-butanol. The high carbon efficiency and low operating temperature are attractive for transforming natural gas-derived methanol to longer-chain liquid fuels and other chemical derivatives. PMID:25355907

Mapping Microbial Carbon Substrate Utilization Across Permafrost Thaw

NASA Astrophysics Data System (ADS)

Anderson, D.; Rich, V. I.; Hodgkins, S. B.; Tfaily, M.; Chanton, J.

2014-12-01

Permafrost thaw is likely to create a substantial positive feedback to climate warming, as previously frozen carbon becomes bioavailable and is released to the atmosphere. Microbes mediate this release, while also consuming "new" carbon from plant inputs and middle-aged soil carbon pools in the seasonally-thawed active layer overlying permafrost. This carbon consumption releases carbon dioxide (CO2) and methane (CH4), both potent greenhouse gases. To investigate microbial carbon cycling in this changing habitat, we examined how microbial communities' carbon substrate degradation changes along a natural permafrost thaw gradient in Stordalen Mire (68.35°N, 19.05°E), northern Sweden. At this location, intermediate thaw creates Sphagnum moss-dominated bogs, while complete thaw results in Eriophorum sedge-dominated fens. The progression of thaw results in increasing organic matter lability (Hodgkins et al, 2014), shifting microbial community composition (Mondav & Woodcroft et al 2014), and changing carbon gas emissions (McCalley et al, in review). However, the inter-relationship of the first two in producing the third remains unclear. We analyzed microbial carbon substrate utilization in the intermediate-thaw and full-thaw sites by two incubation-based methods. We used Biolog EcoPlates, which contain 31 ecologically relevant carbon substrates and a colorimetric marker of their consumption, and into which we added a soil liquid suspension. In addition, we performed mason-jar incubations of peat with carbon substrate amendments and measured CH4 and CO2 emissions. Preliminary Biolog Ecoplate incubations showed that intermediate-thaw features responded faster and more strongly overall to a wide range of substrates relative to the full-thaw features. Preliminary mason jar incubations showed that acetate amendment elicited the greatest response increase in CH4 production and the second greatest increase in CO2 production relative to the controls, in samples from both habitats. In addition, the lowest CH4 and CO2 production was seen in amendments of sphagnum acid. It is important to understand the carbon substrate utilization occurring at these initial and advanced thaw features to speculate the degree to which various carbon inputs are being metabolized to produce the observed gas emissions.

Use of the electrosurgical unit in a carbon dioxide atmosphere.

PubMed

Culp, William C; Kimbrough, Bradly A; Luna, Sarah; Maguddayao, Aris J; Eidson, Jack L; Paolino, David V

2016-01-01

The electrosurgical unit (ESU) utilizes an electrical discharge to cut and coagulate tissue and is often held above the surgical site, causing a spark to form. The voltage at which the spark is created, termed the breakdown voltage, is governed by the surrounding gaseous environment. Surgeons are now utilizing the ESU laparoscopically with carbon dioxide insufflation, potentially altering ESU operating characteristics. This study examines the clinical implications of altering gas composition by measuring the spark gap distance as a marker of breakdown voltage and use of the ESU on a biologic model, both in room air and carbon dioxide. Paschen's Law predicted a 35% decrease in gap distance in carbon dioxide, while testing revealed an average drop of 37-47% as compared to air. However, surgical model testing revealed no perceivable clinical difference. Electrosurgery can be performed in carbon dioxide environments, although surgeons should be aware of potentially altered ESU performance.

Isolation and characterization of yeasts capable of efficient utilization of hemicellulosic hydrolyzate as the carbon source.

PubMed

Cassa-Barbosa, L A; Procópio, R E L; Matos, I T S R; Filho, S A

2015-09-28

Few yeasts have shown the potential to efficiently utilize hemicellulosic hydrolyzate as the carbon source. In this study, microorganisms isolated from the Manaus region in Amazonas, Brazil, were characterized based on their utilization of the pentoses, xylose, and arabinose. The yeasts that showed a potential to assimilate these sugars were selected for the better utilization of lignocellulosic biomass. Two hundred and thirty seven colonies of unicellular microorganisms grown on hemicellulosic hydrolyzate, xylose, arabinose, and yeast nitrogen base selective medium were analyzed. Of these, 231 colonies were subjected to sugar assimilation tests. One hundred and twenty five of these were shown to utilize hydrolyzed hemicellulose, xylose, or arabinose as the carbon source for growth. The colonies that showed the best growth (N = 57) were selected, and their internal transcribed spacer-5.8S rDNA was sequenced. The sequenced strains formed four distinct groups in the phylogenetic tree, and showed a high percentage of similarity with Meyerozyma caribbica, Meyerozyma guilliermondii, Trichosporon mycotoxinivorans, Trichosporon loubieri, Pichia kudriavzevii, Candida lignohabitans, and Candida ethanolica. The discovery of these xylose-fermenting yeasts could attract widespread interest, as these can be used in the cost-effective production of liquid fuel from lignocellulosic materials.

Making Activated Carbon for Storing Gas

NASA Technical Reports Server (NTRS)

Wojtowicz, Marek A.; Serio, Michael A.; Suuberg, Eric M.

2005-01-01

Solid disks of microporous activated carbon, produced by a method that enables optimization of pore structure, have been investigated as means of storing gas (especially hydrogen for use as a fuel) at relatively low pressure through adsorption on pore surfaces. For hydrogen and other gases of practical interest, a narrow distribution of pore sizes <2 nm is preferable. The present method is a variant of a previously patented method of cyclic chemisorption and desorption in which a piece of carbon is alternately (1) heated to the lower of two elevated temperatures in air or other oxidizing gas, causing the formation of stable carbon/oxygen surface complexes; then (2) heated to the higher of the two elevated temperatures in flowing helium or other inert gas, causing the desorption of the surface complexes in the form of carbon monoxide. In the present method, pore structure is optimized partly by heating to a temperature of 1,100 C during carbonization. Another aspect of the method exploits the finding that for each gas-storage pressure, gas-storage capacity can be maximized by burning off a specific proportion (typically between 10 and 20 weight percent) of the carbon during the cyclic chemisorption/desorption process.

Dishonest Academic Conduct: From the Perspective of the Utility Function.

PubMed

Sun, Ying; Tian, Rui

Dishonest academic conduct has aroused extensive attention in academic circles. To explore how scholars make decisions according to the principle of maximal utility, the author has constructed the general utility function based on the expected utility theory. The concrete utility functions of different types of scholars were deduced. They are as follows: risk neutral, risk averse, and risk preference. Following this, the assignment method was adopted to analyze and compare the scholars' utilities of academic conduct. It was concluded that changing the values of risk costs, internal condemnation costs, academic benefits, and the subjective estimation of penalties following dishonest academic conduct can lead to changes in the utility of academic dishonesty. The results of the current study suggest that within scientific research, measures to prevent and govern dishonest academic conduct should be formulated according to the various effects of the above four variables.

Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN

PubMed Central

Morrill, Penny L.; Brazelton, William J.; Kohl, Lukas; Rietze, Amanda; Miles, Sarah M.; Kavanagh, Heidi; Schrenk, Matthew O.; Ziegler, Susan E.; Lang, Susan Q.

2014-01-01

Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in 13C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ13C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO. PMID:25431571

Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN.

PubMed

Morrill, Penny L; Brazelton, William J; Kohl, Lukas; Rietze, Amanda; Miles, Sarah M; Kavanagh, Heidi; Schrenk, Matthew O; Ziegler, Susan E; Lang, Susan Q

2014-01-01

Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in (13)C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ(13)C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

Configuration of Materially Retained Carbon in Our Society: A WIO-MFA-Based Approach for Japan.

PubMed

Ohno, Hajime; Sato, Hirokazu; Fukushima, Yasuhiro

2018-04-03

To achieve the goals of Paris Agreement, global society is directing much effort in substantially reducing greenhouse gas (GHG) emissions. In addition to energy-related efforts, prevention of carbon release into the atmosphere with carbon capture and storage (CCS) and/or utilization of biomass resources is considered indispensable to achieving the global objective. In this study, considering carbon-containing goods as carbon reservoirs in our society similar to forests and reservoirs enabling CCS, the flow of materially utilized carbon was quantified by input-output-based material flow analysis (IO-MFA). As a result, in 2011, 6.3 Mt-C of petroleum-derived carbon and 7.9 Mt-C of wood-derived carbon were introduced to the Japanese society as end-use products (e.g., automobiles and constructions) in various forms (e.g., plastics and synthetic rubbers). The total amount (14.2 Mt-C) corresponded to 4.1% (52.1 Mt-CO 2 ) of annual CO 2 emission in Japan in 2011. Subsequently, by referring to the technology that can treat carbon in the target forms in end-of-life products, the recoverability of carbon as a material has been discussed with respect to each form and end-use of carbon. By numerically showing the necessity and potential of implementing appropriate technologies, this study provides scientific direction for policymakers to establish a quality carbon cycle in our society.

Sympodial bamboo species differ in carbon bio-sequestration and stocks within phytoliths of leaf litters and living leaves.

PubMed

Xiang, Tingting; Ying, Yuqi; Teng, Jiangnan; Huang, Zhangting; Wu, Jiasen; Meng, Cifu; Jiang, Peikun; Tang, Caixian; Li, Jianmin; Zheng, Rong

2016-10-01

Phytolith-occluded carbon (PhytOC) with high resistance against decomposition is an important carbon (C) sink in many ecosystems. This study compared concentrations of phytolith in plants and the PhytOC production of seven sympodial bamboo species in southern China, aiming to provide the information for the managed bamboo plantation and selection of bamboo species to maximize phytolith C sequestration. Leaf litters and living leaves of seven sympodial bamboo species were collected from the field sites. Concentrations of phytoliths, silicon (Si), and PhytOC in leaf litters and living leaves were measured. Carbon sequestration as PhytOC was estimated. There was a considerable variation in the PhytOC concentrations in the leaf litters and living leaves among the seven bamboo species. The mean concentrations of PhytOC ranged from 3.4 to 6.9 g kg(-1) in leaf litters and from 1.6 to 5.9 g kg(-1) in living leaves, with the PhytOC production rates ranging from 5.7 to 52.3 kg e-CO2 ha(-1) year(-1) as leaf litters. Dendrocalamopsis oldhami (Munro) Keng f. had the highest PhytOC production rate. Based on a bio-sequestration rate of 52.3 kg e-CO2 ha(-1) year(-1), we estimated that the current 8 × 10(5) ha of sympodial bamboo stands in China could potentially acquire 4.2 × 10(4) t e-CO2 yearly via phytolith carbon. Furthermore, the seven sympodial bamboo species stored 5.38 × 10(5) t e-CO2 as PhytOC in living leaves and leaf litters in China. It is concluded that sympodial bamboos make a significant contribution to C sequestration and that to maximize the PhytOC accumulation, the bamboo species with the highest PhytOC production rate should be selected for plantation.

Production of ethanol and arabitol by Debaryomyces nepalensis: influence of process parameters

PubMed Central

2013-01-01

Debaryomyces nepalensis, osmotolerant yeast isolated from rotten apple, is known to utilize both hexoses and pentoses and produce industrially important metabolites like ethanol, xylitol and arabitol. In the present study, the effect of different growth substrates, trace elements, nitrogen concentration and initial pH on growth and formation of ethanol and arabitol were examined. Optimum conditions for maximizing the product yields were established: glucose as carbon source, an initial pH of 6.0, 6 g/L of ammonium sulphate and addition of micronutrients. Under these best suited conditions, a concentration of 11g/L of arabitol and 19 g/L of ethanol was obtained in shake flask fermentations. The fermentation was scaled up to 2.5 L bioreactor and the influence of aeration, agitation and initial substrate concentration was also determined. Under optimal conditions (150 g/L glucose, 400 rpm and 0.5 vvm) ethanol concentration reached 52 g/L, which corresponds to a yield of 0.34 g/g and volumetric productivity of 0.28 g/L/h, whereas arabitol production reached a maximum of 14 g/L with a yield and volumetric productivity of 0.1 g/g and 0.07 g/L/h respectively. PMID:23659479

Designing optimized ultra-lightweighted mirror structures made of Cesic for space and ground based applications

NASA Astrophysics Data System (ADS)

Hofbauer, Peter; Krödel, Matthias R.

2010-07-01

Today's space applications increasingly utilize lightweighted construction concepts, motivated by the demands of manufacturing and functionality, and by economics. Particularly for space optics, mirror stability and stiffness need to be maximized, while mass needs to be minimized. Therefore, mirror materials must possess, besides high material strength and manufacturing versatility, high thermal conductivity combined with low heat capacity and long-term stability against varying thermal loads. Additionally, optical surfaces need to be compatible with reflective coating materials. In order to achieve these requirements, the interplay between material properties and mirror design on one hand, and budgetary constraints on the other must be considered. In this paper, we address these issues by presenting an FEM design study of open and closed-back mirror structures with extremely thin reinforcing ribs, with the goal of obtaining optimal physical and optical characteristics. Furthermore, we show that ECM's carbon-fiber reinforced SiC composite, Cesic®, and its newly developed, HB-Cesic® , with their low CTE, low density, and high stiffness, are not only excellent mirror materials, but allow the rapid manufacturing of complex monolithic optical structures at reasonable cost.

Industrial wastewater treatment in a new gas-induced ozone reactor.

PubMed

Lin, Sheng H; Wang, Ching H

2003-03-17

The present work was to investigate industrial wastewater treatment by ozonation in a new gas-induced reactor in conjunction with chemical coagulation pretreatment. The reactor was specifically designed in a fashion that gas induction was created on the liquid surface by the high-speed action of an impeller turbine inside a draft tube to maximize the ozone gas utilization. A new design feature of the present reactor system was a fixed granular activated carbon (GAC) bed packed in a circular compartment between the reactor wall and the shaft tube. The fixed GAC bed provided additional adsorption and catalytic degradation of organic pollutants. Combination of the fixed GAC bed and ozonation results in enhanced oxidation of organic pollutants. In addition to enhanced pollutant oxidation, ozonation was found to provide in situ GAC regeneration that was considered crucial in the present reaction system. Kinetic investigations were also made using a proposed complex kinetic model to elucidate the possible oxidation reaction mechanisms of the present gas-induced ozonation system. As a complementary measure, chemical coagulation pretreatment was found able to achieve up to 50% COD and 85% ADMI removal. Experimental tests were conducted to identify its optimum operating conditions. Copyright 2003 Elsevier Science B.V.

Effects of lung ventilation–perfusion and muscle metabolism–perfusion heterogeneities on maximal O2 transport and utilization

PubMed Central

Cano, I; Roca, J; Wagner, P D

2015-01-01

Previous models of O2 transport and utilization in health considered diffusive exchange of O2 in lung and muscle, but, reasonably, neglected functional heterogeneities in these tissues. However, in disease, disregarding such heterogeneities would not be justified. Here, pulmonary ventilation–perfusion and skeletal muscle metabolism–perfusion mismatching were added to a prior model of only diffusive exchange. Previously ignored O2 exchange in non-exercising tissues was also included. We simulated maximal exercise in (a) healthy subjects at sea level and altitude, and (b) COPD patients at sea level, to assess the separate and combined effects of pulmonary and peripheral functional heterogeneities on overall muscle O2 uptake ( and on mitochondrial (). In healthy subjects at maximal exercise, the combined effects of pulmonary and peripheral heterogeneities reduced arterial () at sea level by 32 mmHg, but muscle by only 122 ml min−1 (–3.5%). At the altitude of Mt Everest, lung and tissue heterogeneity together reduced by less than 1 mmHg and by 32 ml min−1 (–2.4%). Skeletal muscle heterogeneity led to a wide range of potential among muscle regions, a range that becomes narrower as increases, and in regions with a low ratio of metabolic capacity to blood flow, can exceed that of mixed muscle venous blood. For patients with severe COPD, peak was insensitive to substantial changes in the mitochondrial characteristics for O2 consumption or the extent of muscle heterogeneity. This integrative computational model of O2 transport and utilization offers the potential for estimating profiles of both in health and in diseases such as COPD if the extent for both lung ventilation–perfusion and tissue metabolism–perfusion heterogeneity is known. PMID:25640017

Utilization of porous carbons derived from coconut shell and wood in natural rubber

USDA-ARS?s Scientific Manuscript database

The porous carbons derived from cellulose are renewable and environmentally friendly. Coconut shell and wood derived porous carbons were characterized with elemental analysis, ash content, x-ray diffraction, infrared absorbance, particle size, surface area, and pore volume. The results were compared...

Sustainable Remediation for Enhanced NAPL Recovery from Groundwater

NASA Astrophysics Data System (ADS)

Javaher, M.

2012-12-01

Sustainable remediation relates to the achievement of balance between environmental, social, and economic elements throughout the remedial lifecycle. A significant contributor to this balance is the use of green and sustainable technologies which minimize environmental impacts, while maximizing social and economic benefits of remedial implementation. To this end, a patented mobile vapor energy generation (VEG) technology has been developed targeting variable applications, including onsite soil remediation for unrestricted reuse and enhanced non-aqueous phase liquid (NAPL) recover at the water table. At the core of the mobile VEG technology is a compact, high efficiency vapor generator, which utilizes recycled water and propane within an entirely enclosed system to generate steam as high as 1100°F. Operating within a fully enclosed system and capturing all heat that is generated within this portable system, the VEG technology eliminates all emissions to the atmosphere and yields an undetected carbon footprint with resulting carbon dioxide concentrations that are below ambient levels. Introduction of the steam to the subsurface via existing wells results in a desired change in the NAPL viscosity and the interfacial tension at the soil, water, NAPL interface; in turn, this results in mobilization and capture of the otherwise trapped, weathered NAPL. Approved by the California Air Resources Control Board (and underlying Air Quality Management Districts) and applied in California's San Joaquin Valley, in-well heating of NAPLs trapped at the water table using the VEG technology has proven as effective as electrical resistivity heating (ERH) in changing the viscosity of and mobilizing NAPLs in groundwater in support of recovery, but has achieved these results while minimizing the remedial carbon footprint by 90%, reducing energy use by 99%, and reducing remedial costs by more than 95%. NAPL recovery using VEG has also allowed for completion of source removal historically stalled, thereby eliminating ongoing and future groundwater impacts; in turn, this has increased project efficiency and stakeholder satisfaction by as much as 100%.

Hot as You Like It: Models of the Long-term Temperature History of Earth Under Different Geological Assumptions

NASA Astrophysics Data System (ADS)

Domagal-Goldman, S.; Sheldon, N. D.

2012-12-01

The long-term temperature history of the Earth is a subject of continued, vigorous debate. Past models of the climate of early Earth that utilize paleosol contraints on carbon dioxide struggle to maintain temperatures significantly greater than 0°C. In these models, the incoming stellar radiation is much lower than today, consistent with an expectation that the Sun was significantly fainter at that time. In contrast to these models, many proxies for ancient temperatures suggest much warmer conditions. The surface of the planet seems to have been generally free of glaciers throughout this period, other than a brief glaciation at ~2.9 billion years ago and extensive glaciation at ~2.4 billion years ago. Such glacier-free conditions suggest mean surface temperatures greater than 15°C. Measurements of oxygen isotopes in phosphates are consistent with temperatures in the range of 20-30°C; and similar measurements in cherts suggest temperatures over 50°C. This sets up a paradox. Models constrained by one set of geological proxies cannot reproduce the warm temperatures consistent with another set of geological proxies. In this presentation, we explore several potential resolutions to this paradox. First, we model the early Earth under modern-day conditions, but with the lower solar luminosity expected at the time. The next simulation allows carbon dioxide concentrations to increase up to the limits provided by paleosol constraints. Next, we lower the planet's surface albedo in a manner consistent with greater ocean coverage prior to the complete growth of continents. Finally, we remove all constraints on carbon dioxide and attempt to maximize surface temperatures without any geological constraints on model parameters. This set of experiments will allow us to set up potential resolutions to the paradox, and to drive a conversation on which solutions are capable of incorporating the greatest number of geological and geochemical constraints.

Regional-Scale Forcing and Feedbacks from Alternative Scenarios of Global-Scale Land Use Change

NASA Astrophysics Data System (ADS)

Jones, A. D.; Chini, L. P.; Collins, W.; Janetos, A. C.; Mao, J.; Shi, X.; Thomson, A. M.; Torn, M. S.

2011-12-01

Future patterns of land use change depend critically on the degree to which terrestrial carbon management strategies, such as biological carbon sequestration and biofuels, are utilized in order to mitigate global climate change. Furthermore, land use change associated with terrestrial carbon management induces biogeophysical changes to surface energy budgets that perturb climate at regional and possibly global scales, activating different feedback processes depending on the nature and location of the land use change. As a first step in a broader effort to create an integrated earth system model, we examine two scenarios of future anthropogenic activity generated by the Global Change Assessment Model (GCAM) within the full-coupled Community Earth System Model (CESM). Each scenario stabilizes radiative forcing from greenhouse gases and aerosols at 4.5 W/m^2. In the first, stabilization is achieved through a universal carbon tax that values terrestrial carbon equally with fossil carbon, leading to modest afforestation globally and low biofuel utilization. In the second scenario, stabilization is achieved with a tax on fossil fuel and industrial carbon alone. In this case, biofuel utilization increases dramatically and crop area expands to claim approximately 50% of forest cover globally. By design, these scenarios exhibit identical climate forcing from atmospheric constituents. Thus, differences among them can be attributed to the biogeophysical effects of land use change. In addition, we utilize offline radiative transfer and offline land model simulations to identify forcing and feedback mechanisms operating in different regions. We find that boreal deforestation has a strong climatic signature due to significant albedo change coupled with a regional-scale water vapor feedback. Tropical deforestation, on the other hand, has more subtle effects on climate. Globally, the two scenarios yield warming trends over the 21st century that differ by 0.5 degrees Celsius. This work demonstrates the importance of land use in shaping future patterns of climate change, both globally and regionally.

Spatial differentiation of gene expression in Aspergillus niger colony grown for sugar beet pulp utilization

PubMed Central

Benoit, Isabelle; Zhou, Miaomiao; Vivas Duarte, Alexandra; Downes, Damien J.; Todd, Richard B.; Kloezen, Wendy; Post, Harm; Heck, Albert J. R.; Maarten Altelaar, A. F.; de Vries, Ronald P.

2015-01-01

Degradation of plant biomass to fermentable sugars is of critical importance for the use of plant materials for biofuels. Filamentous fungi are ubiquitous organisms and major plant biomass degraders. Single colonies of some fungal species can colonize massive areas as large as five soccer stadia. During growth, the mycelium encounters heterogeneous carbon sources. Here we assessed whether substrate heterogeneity is a major determinant of spatial gene expression in colonies of Aspergillus niger. We analyzed whole-genome gene expression in five concentric zones of 5-day-old colonies utilizing sugar beet pulp as a complex carbon source. Growth, protein production and secretion occurred throughout the colony. Genes involved in carbon catabolism were expressed uniformly from the centre to the periphery whereas genes encoding plant biomass degrading enzymes and nitrate utilization were expressed differentially across the colony. A combined adaptive response of carbon-catabolism and enzyme production to locally available monosaccharides was observed. Finally, our results demonstrate that A. niger employs different enzymatic tools to adapt its metabolism as it colonizes complex environments. PMID:26314379

Spatial differentiation of gene expression in Aspergillus niger colony grown for sugar beet pulp utilization.

PubMed

Benoit, Isabelle; Zhou, Miaomiao; Vivas Duarte, Alexandra; Downes, Damien J; Todd, Richard B; Kloezen, Wendy; Post, Harm; Heck, Albert J R; Maarten Altelaar, A F; de Vries, Ronald P

2015-08-28

Degradation of plant biomass to fermentable sugars is of critical importance for the use of plant materials for biofuels. Filamentous fungi are ubiquitous organisms and major plant biomass degraders. Single colonies of some fungal species can colonize massive areas as large as five soccer stadia. During growth, the mycelium encounters heterogeneous carbon sources. Here we assessed whether substrate heterogeneity is a major determinant of spatial gene expression in colonies of Aspergillus niger. We analyzed whole-genome gene expression in five concentric zones of 5-day-old colonies utilizing sugar beet pulp as a complex carbon source. Growth, protein production and secretion occurred throughout the colony. Genes involved in carbon catabolism were expressed uniformly from the centre to the periphery whereas genes encoding plant biomass degrading enzymes and nitrate utilization were expressed differentially across the colony. A combined adaptive response of carbon-catabolism and enzyme production to locally available monosaccharides was observed. Finally, our results demonstrate that A. niger employs different enzymatic tools to adapt its metabolism as it colonizes complex environments.

Recent progress in solution plasma-synthesized-carbon-supported catalysts for energy conversion systems

NASA Astrophysics Data System (ADS)

Lun Li, Oi; Lee, Hoonseung; Ishizaki, Takahiro

2018-01-01

Carbon-based materials have been widely utilized as the electrode materials in energy conversion and storage technologies, such as fuel cells and metal-air batteries. In these systems, the oxygen reduction reaction is an important step that determines the overall performance. A novel synthesis route, named the solution plasma process, has been recently utilized to synthesize various types of metal-based and heteroatom-doped carbon catalysts. In this review, we summarize cutting-edge technologies involving the synthesis and modeling of carbon-supported catalysts synthesized via solution plasma process, followed by current progress on the electrocatalytic performance of these catalysts. This review provides the fundamental and state-of-the-art performance of solution-plasma-synthesized electrode materials, as well as the remaining scientific and technological challenges for this process.

Novel hierarchically porous carbon materials obtained from natural biopolymer as host matrixes for lithium-sulfur battery applications.

PubMed

Zhang, Bin; Xiao, Min; Wang, Shuanjin; Han, Dongmei; Song, Shuqin; Chen, Guohua; Meng, Yuezhong

2014-08-13

Novel hierarchically porous carbon materials with very high surface areas, large pore volumes and high electron conductivities were prepared from silk cocoon by carbonization with KOH activation. The prepared novel porous carbon-encapsulated sulfur composites were fabricated by a simple melting process and used as cathodes for lithium sulfur batteries. Because of the large surface area and hierarchically porous structure of the carbon material, soluble polysulfide intermediates can be trapped within the cathode and the volume expansion can be alleviated effectively. Moreover, the electron transport properties of the carbon materials can provide an electron conductive network and promote the utilization rate of sulfur in cathode. The prepared carbon-sulfur composite exhibited a high specific capacity and excellent cycle stability. The results show a high initial discharge capacity of 1443 mAh g(-1) and retain 804 mAh g(-1) after 80 discharge/charge cycles at a rate of 0.5 C. A Coulombic efficiency retained up to 92% after 80 cycles. The prepared hierarchically porous carbon materials were proven to be an effective host matrix for sulfur encapsulation to improve the sulfur utilization rate and restrain the dissolution of polysulfides into lithium-sulfur battery electrolytes.

Effects of medium components and culture conditions on mycelial biomass and the production of bioactive ingredients in submerged culture of Xylaria nigripes (Ascomycetes), a Chinese medicinal fungus.

PubMed

Chen, Jian-Zhi; Lo, Hui-Chen; Lin, Fang-Yi; Chang, Shih-Liang; Hsieh, Changwei; Liang, Zeng-Chin; Ho, Wai-Jane; Hsu, Tai-Hao

2014-01-01

The optimal culture conditions were investigated to maximize the production of mycelial biomass and bioactive ingredients in submerged cultivation of Xylaria nigripes, a Chinese medicinal fungus. The one-factor-at-a-time method was used to explore the effects of medium components, including carbon, nitrogen, mineral sources, and initial pH of the medium and environmental factors, such as culture temperature and rotation speed, on mycelial growth and production of bioactive ingredients. The results indicated that the optimal culture temperature and rotation speed were 25°C and 100 rpm in a medium with 20 g fructose, 6 g yeast extract, and 2 g magnesiun sulfate heptahydrate as carbon, nitrogen, and mineral sources, respectively, in 1 L distilled water with an initial medium pH of 5.5. With optimal medium components and conditions of cultivation, the maximal production of mycelial biomass was 6.64 ± 0.88 g/L, with maximal production of bioactive ingredients such as extracellular polysaccharides (2.36 ± 0.18 mg/mL), intracellular polysaccharides (2.38 ± 0.07 mg/g), adenosine (43.27 ± 2.37 mg/g), total polyphenols (36.57 ± 1.36 mg/g), and triterpenoids (31.29 ± 1.17 mg/g) in a shake flask culture. These results suggest that different bioactive ingredients including intracellular polysaccharides, adenosine, total polyphenols and triterpenoids in mycelia and extracellular polysaccharides in broth can be obtained from one simple medium for submerged cultivation of X. nigripes.

Laser ablative synthesis of carbon nanotubes

DOEpatents

Smith, Michael W.; Jordan, Kevin; Park, Cheol

2010-03-02

An improved method for the production of single walled carbon nanotubes that utilizes an RF-induction heated side-pumped synthesis chamber for the production of such. Such a method, while capable of producing large volumes of carbon nanotubes, concurrently permits the use of a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization. The method of the present invention utilizes a free electron laser operating at high average and peak fluence to illuminate a rotating and translating graphite/catalyst target to obtain high yields of SWNTs without the use of a vacuum chamber.

Stand-alone error characterisation of microwave satellite soil moisture using a Fourier method

USDA-ARS?s Scientific Manuscript database

Error characterisation of satellite-retrieved soil moisture (SM) is crucial for maximizing their utility in research and applications in hydro-meteorology and climatology. Error characteristics can provide insights for retrieval development and validation, and inform suitable strategies for data fus...

Biomass for biorefining: Resources, allocation, utilization, and policies

USDA-ARS?s Scientific Manuscript database

The importance of biomass in the development of renewable energy, the availability and allocation of biomass, its preparation for use in biorefineries, and the policies affecting biomass are discussed in this chapter. Bioenergy development will depend on maximizing the amount of biomass obtained fro...

The Child and Adolescent Psychiatry Trials Network

ERIC Educational Resources Information Center

March, John S.; Silva, Susan G.; Compton, Scott; Anthony, Ginger; DeVeaugh-Geiss, Joseph; Califf, Robert; Krishnan, Ranga

2004-01-01

Objective: The current generation of clinical trials in pediatric psychiatry often fails to maximize clinical utility for practicing clinicians, thereby diluting its impact. Method: To attain maximum clinical relevance and acceptability, the Child and Adolescent Psychiatry Trials Network (CAPTN) will transport to pediatric psychiatry the practical…

Medical Problem-Solving: A Critique of the Literature.

ERIC Educational Resources Information Center

McGuire, Christine H.

1985-01-01

Prescriptive, decision-analysis of medical problem-solving has been based on decision theory that involves calculation and manipulation of complex probability and utility values to arrive at optimal decisions that will maximize patient benefits. The studies offer a methodology for improving clinical judgment. (Author/MLW)

Why is Improving Water Quality in the Gulf of Mexico so Critical?

EPA Pesticide Factsheets

The EPA regional offices and the Gulf of Mexico Program work with Gulf States to continue to maximize the efficiency and utility of water quality monitoring efforts for local managers by coordinating and standardizing state and federal water quality data

Maximizing internal opportunities for healthcare facilities facing a managed-care environment.

PubMed

Gillespie, M

1997-01-01

The primary theme of this article concerns the pressures on healthcare facilities to become efficient utilizers of their existing resources. This acute need for efficiency has been extremely obvious since the changing reimbursement patterns of managed care have proliferated across the nation.

Utilizing Partnerships to Maximize Resources in College Counseling Services

ERIC Educational Resources Information Center

Stewart, Allison; Moffat, Meridith; Travers, Heather; Cummins, Douglas

2015-01-01

Research indicates an increasing number of college students are experiencing severe psychological problems that are impacting their academic performance. However, many colleges and universities operate with constrained budgets that limit their ability to provide adequate counseling services for their student population. Moreover, accessing…

Merton's problem for an investor with a benchmark in a Barndorff-Nielsen and Shephard market.

PubMed

Lennartsson, Jan; Lindberg, Carl

2015-01-01

To try to outperform an externally given benchmark with known weights is the most common equity mandate in the financial industry. For quantitative investors, this task is predominantly approached by optimizing their portfolios consecutively over short time horizons with one-period models. We seek in this paper to provide a theoretical justification to this practice when the underlying market is of Barndorff-Nielsen and Shephard type. This is done by verifying that an investor who seeks to maximize her expected terminal exponential utility of wealth in excess of her benchmark will in fact use an optimal portfolio equivalent to the one-period Markowitz mean-variance problem in continuum under the corresponding Black-Scholes market. Further, we can represent the solution to the optimization problem as in Feynman-Kac form. Hence, the problem, and its solution, is analogous to Merton's classical portfolio problem, with the main difference that Merton maximizes expected utility of terminal wealth, not wealth in excess of a benchmark.

Paracrine communication maximizes cellular response fidelity in wound signaling

PubMed Central

Handly, L Naomi; Pilko, Anna; Wollman, Roy

2015-01-01

Population averaging due to paracrine communication can arbitrarily reduce cellular response variability. Yet, variability is ubiquitously observed, suggesting limits to paracrine averaging. It remains unclear whether and how biological systems may be affected by such limits of paracrine signaling. To address this question, we quantify the signal and noise of Ca2+ and ERK spatial gradients in response to an in vitro wound within a novel microfluidics-based device. We find that while paracrine communication reduces gradient noise, it also reduces the gradient magnitude. Accordingly we predict the existence of a maximum gradient signal to noise ratio. Direct in vitro measurement of paracrine communication verifies these predictions and reveals that cells utilize optimal levels of paracrine signaling to maximize the accuracy of gradient-based positional information. Our results demonstrate the limits of population averaging and show the inherent tradeoff in utilizing paracrine communication to regulate cellular response fidelity. DOI: http://dx.doi.org/10.7554/eLife.09652.001 PMID:26448485

Integrating epidemiology, psychology, and economics to achieve HPV vaccination targets.

PubMed

Basu, Sanjay; Chapman, Gretchen B; Galvani, Alison P

2008-12-02

Human papillomavirus (HPV) vaccines provide an opportunity to reduce the incidence of cervical cancer. Optimization of cervical cancer prevention programs requires anticipation of the degree to which the public will adhere to vaccination recommendations. To compare vaccination levels driven by public perceptions with levels that are optimal for maximizing the community's overall utility, we develop an epidemiological game-theoretic model of HPV vaccination. The model is parameterized with survey data on actual perceptions regarding cervical cancer, genital warts, and HPV vaccination collected from parents of vaccine-eligible children in the United States. The results suggest that perceptions of survey respondents generate vaccination levels far lower than those that maximize overall health-related utility for the population. Vaccination goals may be achieved by addressing concerns about vaccine risk, particularly those related to sexual activity among adolescent vaccine recipients. In addition, cost subsidizations and shifts in federal coverage plans may compensate for perceived and real costs of HPV vaccination to achieve public health vaccination targets.

IMP2, a nuclear gene controlling the mitochondrial dependence of galactose, maltose and raffinose utilization in Saccharomyces cerevisiae.

PubMed

Donnini, C; Lodi, T; Ferrero, I; Puglisi, P P

1992-02-01

The IMP2 gene of Saccharomyces cerevisiae is involved in the nucleo-mitochondrial control of maltose, galactose and raffinose utilization as shown by the inability of imp2 mutants to grow on these carbon sources in respiratory-deficient conditions or in the presence of ethidium bromide and erythromycin. The negative phenotype cannot be scored in the presence of inhibitors of respiration and oxidative phosphorylation, indicating that the role of the mitochondria in the utilization of the above-mentioned carbon sources in imp2 mutants is not at the energetical level. Mutations in the IMP2 gene also confer many phenotypic alterations in respiratory-sufficient conditions, e.g. leaky phenotype on oxidizable carbon sources, sensitivity to heat shock and sporulation deficiency. The IMP2 gene has been cloned, sequenced and disrupted. The phenotype of null imp2 mutants is indistinguishable from that of the originally isolated mutant.

Electrostatic Spray Deposition-Based Manganese Oxide Films-From Pseudocapacitive Charge Storage Materials to Three-Dimensional Microelectrode Integrands.

PubMed

Agrawal, Richa; Adelowo, Ebenezer; Baboukani, Amin Rabiei; Villegas, Michael Franc; Henriques, Alexandra; Wang, Chunlei

2017-07-26

In this study, porous manganese oxide (MnO x ) thin films were synthesized via electrostatic spray deposition (ESD) and evaluated as pseudocapacitive electrode materials in neutral aqueous media. Very interestingly, the gravimetric specific capacitance of the ESD-based electrodes underwent a marked enhancement upon electrochemical cycling, from 72 F∙g -1 to 225 F∙g -1 , with a concomitant improvement in kinetics and conductivity. The change in capacitance and resistivity is attributed to a partial electrochemical phase transformation from the spinel-type hausmannite Mn₃O₄ to the conducting layered birnessite MnO₂. Furthermore, the films were able to retain 88.4% of the maximal capacitance after 1000 cycles. Upon verifying the viability of the manganese oxide films for pseudocapacitive applications, the thin films were integrated onto carbon micro-pillars created via carbon microelectromechanical systems (C-MEMS) for examining their application as potential microelectrode candidates. In a symmetric two-electrode cell setup, the MnO x /C-MEMS microelectrodes were able to deliver specific capacitances as high as 0.055 F∙cm -2 and stack capacitances as high as 7.4 F·cm -3 , with maximal stack energy and power densities of 0.51 mWh·cm -3 and 28.3 mW·cm -3 , respectively. The excellent areal capacitance of the MnO x -MEs is attributed to the pseudocapacitive MnO x as well as the three-dimensional architectural framework provided by the carbon micro-pillars.

Leaf conductance and carbon gain under salt-stressed conditions

NASA Astrophysics Data System (ADS)

Volpe, V.; Manzoni, S.; Marani, M.; Katul, G.

2011-12-01

Exposure of plants to salt stress is often accompanied by reductions in leaf photosynthesis and in stomatal and mesophyll conductances. To separate the effects of salt stress on these quantities, a model based on the hypothesis that carbon gain is maximized subject to a water loss cost is proposed. The optimization problem of adjusting stomatal aperture for maximizing carbon gain at a given water loss is solved for both a non-linear and a linear biochemical demand function. A key novel theoretical outcome of the optimality hypothesis is an explicit relationship between the stomatal and mesophyll conductances that can be evaluated against published measurements. The approaches here successfully describe gas-exchange measurements reported for olive trees (Olea europea L.) and spinach (Spinacia oleraceaL.) in fresh water and in salt-stressed conditions. Salt stress affected both stomatal and mesophyll conductances and photosynthetic efficiency of both species. The fresh water/salt water comparisons show that the photosynthetic capacity is directly reduced by 30%-40%, indicating that reductions in photosynthetic rates under increased salt stress are not due only to a limitation of CO2diffusion. An increase in salt stress causes an increase in the cost of water parameter (or marginal water use efficiency) exceeding 100%, analogous in magnitude to findings from extreme drought stress studies. The proposed leaf-level approach can be incorporated into physically based models of the soil-plant-atmosphere system to assess how saline conditions and elevated atmospheric CO2 jointly impact transpiration and photosynthesis.

Recovery Act: Brea California Combined Cycle Electric Generating Plant Fueled by Waste Landfill Gas

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

Galowitz, Stephen

The primary objective of the Project was to maximize the productive use of the substantial quantities of waste landfill gas generated and collected at the Olinda Landfill near Brea, California. An extensive analysis was conducted and it was determined that utilization of the waste gas for power generation in a combustion turbine combined cycle facility was the highest and best use. The resulting Project reflected a cost effective balance of the following specific sub-objectives: • Meeting the environmental and regulatory requirements, particularly the compliance obligations imposed on the landfill to collect, process and destroy landfill gas • Utilizing proven andmore » reliable technology and equipment • Maximizing electrical efficiency • Maximizing electric generating capacity, consistent with the anticipated quantities of landfill gas generated and collected at the Olinda Landfill • Maximizing equipment uptime • Minimizing water consumption • Minimizing post-combustion emissions • The Project produced and will produce a myriad of beneficial impacts. o The Project created 360 FTE construction and manufacturing jobs and 15 FTE permanent jobs associated with the operation and maintenance of the plant and equipment. o By combining state-of-the-art gas clean up systems with post combustion emissions control systems, the Project established new national standards for best available control technology (BACT). o The Project will annually produce 280,320 MWh’s of clean energy o By destroying the methane in the landfill gas, the Project will generate CO2 equivalent reductions of 164,938 tons annually. The completed facility produces 27.4 MWnet and operates 24 hours a day, seven days a week.« less

Carbon with hierarchical pores from carbonized metal-organic frameworks for lithium sulphur batteries.

PubMed

Xi, Kai; Cao, Shuai; Peng, Xiaoyu; Ducati, Caterina; Kumar, R Vasant; Cheetham, Anthony K

2013-03-18

This paper presents a novel method and rationale for utilizing carbonized MOFs for sulphur loading to fabricate cathode structures for lithium-sulphur batteries. Unique carbon materials with differing hierarchical pore structures were synthesized from four types of zinc-containing metal-organic frameworks (MOFs). It is found that cathode materials made from MOFs-derived carbons with higher mesopore (2-50 nm) volumes exhibit increased initial discharge capacities, whereas carbons with higher micropore (<2 nm) volumes lead to cathode materials with better cycle stability.

Establishing rational networking using the DL04 quantum secure direct communication protocol

NASA Astrophysics Data System (ADS)

Qin, Huawang; Tang, Wallace K. S.; Tso, Raylin

2018-06-01

The first rational quantum secure direct communication scheme is proposed, in which we use the game theory with incomplete information to model the rational behavior of the participant, and give the strategy space and utility function. The rational participant can get his maximal utility when he performs the protocol faithfully, and then the Nash equilibrium of the protocol can be achieved. Compared to the traditional schemes, our scheme will be more practical in the presence of rational participant.

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

Beckley, D.A.; Stites, J. Jr.

The objective was to characterize several lots of materials used for carbon/carbon and carbon/phenol product manufacture. Volume one is organized into testing categories based on raw material of product form. Each category contains a discussion of the sampling plan, comments and observations on each test method utilized, and a summary of the results obtained each category.

STABLE CARBON ISOTOPE EVIDENCE FOR COUPLING BETWEEN SEDIMENTARY BACTERIA AND SEAGRASSES IN A SUB-TROPICAL LAGOON

EPA Science Inventory

We measured stable carbon isotope ratios (d13C) in phospholipid fatty acids (PLFAs) to identify the primary carbon source utilized by sedimentary bacteria in Lower Laguna Madre, Texas, which is a seagrass dominated lagoon. Comparisons were made between three differing habitat ty...

Enhancing substrate utilization and power production of a microbial fuel cell with nitrogen-doped carbon aerogel as cathode catalyst.

PubMed

Tardy, Gábor Márk; Lóránt, Bálint; Lóka, Máté; Nagy, Balázs; László, Krisztina

2017-07-01

Catalytic efficiency of a nitrogen-doped, mesoporous carbon aerogel cathode catalyst was investigated in a two-chambered microbial fuel cell (MFC) applying graphite felt as base material for cathode and anode, utilizing peptone as carbon source. This mesoporous carbon aerogel containing catalyst layer on the cathode increased the maximum power density normalized to the anode volume to 2.7 times higher compared to the maximum power density obtained applying graphite felt cathode without the catalyst layer. At high (2 and 3) cathode/anode volume ratios, maximum power density exceeded 40 W m -3 . At the same time, current density and specific substrate utilization rate increased by 58% resulting in 31.9 A m -3 and 18.8 g COD m -3  h -1 , respectively (normalized to anode volume). Besides the increase of the power and the rate of biodegradation, the investigated catalyst decreased the internal resistance from the range of 450-600 to 350-370 Ω. Although Pt/C catalyst proved to be more efficient, a considerable decrease in the material costs might be achieved by substituting it with nitrogen-doped carbon aerogel in MFCs. Such cathode still displays enhanced catalytic effect.

Carbon stocks across a chronosequence of thinned and unmanaged red pine (Pinus resinosa) stands

Treesearch

Matthew D. Powers; Randall K. Kolka; John B. Bradford; Brian J. Palik; Shawn Fraver; Martin F. Jurgensen

2012-01-01

Forests function as a major global C sink, and forest management strategies that maximize C stocks offer one possible means of mitigating the impacts of increasing anthropogenic CO2 emissions. We studied the effects of thinning, a common management technique in many forest types, on age-related trends in C stocks using a chronosequence of thinned...

Cell separator for use in bipolar-stack energy storage devices

DOEpatents

Mayer, Steven T.; Feikert, John H.; Kachmitter, James L.; Pekala, Richard W.

1995-01-01

An improved multi-cell electrochemical energy storage device, such as a battery, fuel cell, or double layer capacitor using a cell separator which allows cells to be stacked and interconnected with low electrical resistance and high reliability while maximizing packaging efficiency. By adding repeating cells, higher voltages can be obtained. The cell separator is formed by applying an organic adhesive on opposing surfaces of adjacent carbon electrodes or surfaces of aerogel electrodes of a pair of adjacent cells prior to or after pyrolysis thereof to form carbon aerogel electrodes. The cell separator is electronically conductive, but ionically isolating, preventing an electrolytic conduction path between adjacent cells in the stack.

Characterizing SWCNT Dispersion in Polymer Composites

NASA Technical Reports Server (NTRS)

Lillehei, Peter T.; Kim, Jae-Woo; Gibbons, Luke; Park, Cheol

2007-01-01

The new wave of single wall carbon nanotube (SWCNT) infused composites will yield structurally sound multifunctional nanomaterials. The SWCNT network requires thorough dispersion within the polymer matrix in order to maximize the benefits of the nanomaterial. However, before any nanomaterials can be used in aerospace applications a means of quality assurance and quality control must be certified. Quality control certification requires a means of quantification, however, the measurement protocol mandates a method of seeing the dispersion first. We describe here the new tools that we have developed and implemented to first be able to see carbon nanotubes in polymers and second to measure or quantify the dispersion of the nanotubes.

Carbon utilization profile of the filamentous fungal species Fusarium fujikuroi, Penicillium decumbens, and Sarocladium strictum isolated from marine coastal environments.

PubMed

Fuentes, Marcelo E; Quiñones, Renato A

Facultative marine filamentous fungi have recently emerged as a functional component in coastal marine systems. However, little is known about their ecological role and functions in biogeochemical cycles. Penicillium decumbens, S. strictum, and F. fujikuroi were isolated from the coastal upwelling zone off south-central Chile. Their carbon profiles were characterized using Biolog FF MicroPlates. These species used a wide range of carbon sources, mainly carbohydrates, but also amino acids, suggesting the use of metabolic routes that include glycolysis/gluconeogenesis. Substrate richness revealed a great capacity for the utilization of nutritional sources, reflected by the following Shannon Indices of utilization of specific substrates: 4.02 for S. strictum, 4.01 for P. decumbes, and 3.91 for F. fujikuroi, which reveals a high physiological capacity for oxidizing different substrates. Significant differences were found between 18 substrates utilized by all three species. Results suggest that filamentous fungi should be considered an integral part of the marine microbial community and included in biogeochemical cycling models of upwelling ecosystems.

Effects of overexpressing photosynthetic carbon flux control enzymes in the cyanobacterium Synechocystis PCC 6803.

PubMed

Liang, Feiyan; Lindblad, Peter

2016-11-01

Synechocystis PCC 6803 is a model unicellular cyanobacterium used in e.g. photosynthesis and CO 2 assimilation research. In the present study we examined the effects of overexpressing Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), sedoheptulose 1,7-biphosphatase (SBPase), fructose-bisphosphate aldolase (FBA) and transketolase (TK), confirmed carbon flux control enzymes of the Calvin-Bassham-Benson (CBB) cycle in higher plants, in Synechocystis PCC 6803. Overexpressing RuBisCO, SBPase and FBA resulted in increased in vivo oxygen evolution (maximal 115%), growth rate and biomass accumulation (maximal 52%) under 100μmolphotonsm -2 s -1 light condition. Cells overexpressing TK showed a chlorotic phenotype but increased biomass by approximately 42% under 100μmolphotonsm -2 s -1 light condition. Under 15μmolphotonsm -2 s -1 light condition, cells overexpressing TK showed enhanced in vivo oxygen evolution. This study demonstrates increased growth and biomass accumulation when overexpressing selected enzymes of the CBB cycle. RuBisCO, SBPase, FBA and TK are identified as four potential targets to improve growth and subsequently also yield of valuable products from Synechocystis PCC 6803. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Hybrid Carbon-Based Scaffolds for Applications in Soft Tissue Reconstruction

PubMed Central

Lafdi, Khalid; Joseph, Robert M.; Tsonis, Panagiotis A.

2012-01-01

Current biomedical scaffolds utilized in surgery to repair soft tissues commonly fail to meet the optimal combination of biomechanical and tissue regenerative properties. Carbon is a scaffold alternative that potentially optimizes the balance between mechanical strength, durability, and function as a cell and biologics delivery vehicle that is necessary to restore tissue function while promoting tissue repair. The goals of this study were to investigate the feasibility of fabricating hybrid fibrous carbon scaffolds modified with biopolymer, polycaprolactone and to analyze their mechanical properties and ability to support cell growth and proliferation. Environmental scanning electron microscopy, micro-computed tomography, and cell adhesion and cell proliferation studies were utilized to test scaffold suitability as a cell delivery vehicle. Mechanical properties were tested to examine load failure and elastic modulus. Results were compared to an acellular dermal matrix scaffold control (GraftJacket® [GJ] Matrix), selected for its common use in surgery for the repair of soft tissues. Results indicated that carbon scaffolds exhibited similar mechanical maximums and capacity to support fibroblast adhesion and proliferation in comparison with GJ. Fibroblast adhesion and proliferation was collinear with carbon fiber orientation in regions of sparsely distributed fibers and occurred in clusters in regions of higher fiber density and low porosity. Overall, fibroblast adhesion and proliferation was greatest in lower porosity carbon scaffolds with highly aligned fibers. Stepwise multivariate regression showed that the variability in maximum load of carbon scaffolds and controls were dependent on unique and separate sets of parameters. These finding suggested that there were significant differences in the functional implications of scaffold design and material properties between carbon and dermis derived scaffolds that affect scaffold utility as a tissue replacement construct. PMID:22092333

Poultry litter-based activated carbon for removing heavy metal ions in water.

PubMed

Guo, Mingxin; Qiu, Guannan; Song, Weiping

2010-02-01

Utilization of poultry litter as a precursor material to manufacture activated carbon for treating heavy metal-contaminated water is a value-added strategy for recycling the organic waste. Batch adsorption experiments were conducted to investigate kinetics, isotherms, and capacity of poultry litter-based activated carbon for removing heavy metal ions in water. It was revealed that poultry litter-based activated carbon possessed significantly higher adsorption affinity and capacity for heavy metals than commercial activated carbons derived from bituminous coal and coconut shell. Adsorption of metal ions onto poultry litter-based carbon was rapid and followed Sigmoidal Chapman patterns as a function of contact time. Adsorption isotherms could be described by different models such as Langmuir and Freundlich equations, depending on the metal species and the coexistence of other metal ions. Potentially 404 mmol of Cu2+, 945 mmol of Pb2+, 236 mmol of Zn2+, and 250-300 mmol of Cd2+ would be adsorbed per kg of poultry litter-derived activated carbon. Releases of nutrients and metal ions from litter-derived carbon did not pose secondary water contamination risks. The study suggests that poultry litter can be utilized as a precursor material for economically manufacturing granular activated carbon that is to be used in wastewater treatment for removing heavy metals.

Maximizing the Impact of e-Therapy and Serious Gaming: Time for a Paradigm Shift.

PubMed

Fleming, Theresa M; de Beurs, Derek; Khazaal, Yasser; Gaggioli, Andrea; Riva, Giuseppe; Botella, Cristina; Baños, Rosa M; Aschieri, Filippo; Bavin, Lynda M; Kleiboer, Annet; Merry, Sally; Lau, Ho Ming; Riper, Heleen

2016-01-01

Internet interventions for mental health, including serious games, online programs, and apps, hold promise for increasing access to evidence-based treatments and prevention. Many such interventions have been shown to be effective and acceptable in trials; however, uptake and adherence outside of trials is seldom reported, and where it is, adherence at least, generally appears to be underwhelming. In response, an international Collaboration On Maximizing the impact of E-Therapy and Serious Gaming (COMETS) was formed. In this perspectives' paper, we call for a paradigm shift to increase the impact of internet interventions toward the ultimate goal of improved population mental health. We propose four pillars for change: (1) increased focus on user-centered approaches, including both user-centered design of programs and greater individualization within programs, with the latter perhaps utilizing increased modularization; (2) Increased emphasis on engagement utilizing processes such as gaming, gamification, telepresence, and persuasive technology; (3) Increased collaboration in program development, testing, and data sharing, across both sectors and regions, in order to achieve higher quality, more sustainable outcomes with greater reach; and (4) Rapid testing and implementation, including the measurement of reach, engagement, and effectiveness, and timely implementation. We suggest it is time for researchers, clinicians, developers, and end-users to collaborate on these aspects in order to maximize the impact of e-therapies and serious gaming.

Maximizing the Impact of e-Therapy and Serious Gaming: Time for a Paradigm Shift

PubMed Central

Fleming, Theresa M.; de Beurs, Derek; Khazaal, Yasser; Gaggioli, Andrea; Riva, Giuseppe; Botella, Cristina; Baños, Rosa M.; Aschieri, Filippo; Bavin, Lynda M.; Kleiboer, Annet; Merry, Sally; Lau, Ho Ming; Riper, Heleen

2016-01-01

Internet interventions for mental health, including serious games, online programs, and apps, hold promise for increasing access to evidence-based treatments and prevention. Many such interventions have been shown to be effective and acceptable in trials; however, uptake and adherence outside of trials is seldom reported, and where it is, adherence at least, generally appears to be underwhelming. In response, an international Collaboration On Maximizing the impact of E-Therapy and Serious Gaming (COMETS) was formed. In this perspectives’ paper, we call for a paradigm shift to increase the impact of internet interventions toward the ultimate goal of improved population mental health. We propose four pillars for change: (1) increased focus on user-centered approaches, including both user-centered design of programs and greater individualization within programs, with the latter perhaps utilizing increased modularization; (2) Increased emphasis on engagement utilizing processes such as gaming, gamification, telepresence, and persuasive technology; (3) Increased collaboration in program development, testing, and data sharing, across both sectors and regions, in order to achieve higher quality, more sustainable outcomes with greater reach; and (4) Rapid testing and implementation, including the measurement of reach, engagement, and effectiveness, and timely implementation. We suggest it is time for researchers, clinicians, developers, and end-users to collaborate on these aspects in order to maximize the impact of e-therapies and serious gaming. PMID:27148094

Identifying Epigenetic Biomarkers using Maximal Relevance and Minimal Redundancy Based Feature Selection for Multi-Omics Data.

PubMed

Mallik, Saurav; Bhadra, Tapas; Maulik, Ujjwal

2017-01-01

Epigenetic Biomarker discovery is an important task in bioinformatics. In this article, we develop a new framework of identifying statistically significant epigenetic biomarkers using maximal-relevance and minimal-redundancy criterion based feature (gene) selection for multi-omics dataset. Firstly, we determine the genes that have both expression as well as methylation values, and follow normal distribution. Similarly, we identify the genes which consist of both expression and methylation values, but do not follow normal distribution. For each case, we utilize a gene-selection method that provides maximal-relevant, but variable-weighted minimum-redundant genes as top ranked genes. For statistical validation, we apply t-test on both the expression and methylation data consisting of only the normally distributed top ranked genes to determine how many of them are both differentially expressed andmethylated. Similarly, we utilize Limma package for performing non-parametric Empirical Bayes test on both expression and methylation data comprising only the non-normally distributed top ranked genes to identify how many of them are both differentially expressed and methylated. We finally report the top-ranking significant gene-markerswith biological validation. Moreover, our framework improves positive predictive rate and reduces false positive rate in marker identification. In addition, we provide a comparative analysis of our gene-selection method as well as othermethods based on classificationperformances obtained using several well-known classifiers.

Understanding the factors that effect maximal fat oxidation.

PubMed

Purdom, Troy; Kravitz, Len; Dokladny, Karol; Mermier, Christine

2018-01-01

Lipids as a fuel source for energy supply during submaximal exercise originate from subcutaneous adipose tissue derived fatty acids (FA), intramuscular triacylglycerides (IMTG), cholesterol and dietary fat. These sources of fat contribute to fatty acid oxidation (FAox) in various ways. The regulation and utilization of FAs in a maximal capacity occur primarily at exercise intensities between 45 and 65% VO 2max , is known as maximal fat oxidation (MFO), and is measured in g/min. Fatty acid oxidation occurs during submaximal exercise intensities, but is also complimentary to carbohydrate oxidation (CHOox). Due to limitations within FA transport across the cell and mitochondrial membranes, FAox is limited at higher exercise intensities. The point at which FAox reaches maximum and begins to decline is referred to as the crossover point. Exercise intensities that exceed the crossover point (~65% VO 2max ) utilize CHO as the predominant fuel source for energy supply. Training status, exercise intensity, exercise duration, sex differences, and nutrition have all been shown to affect cellular expression responsible for FAox rate. Each stimulus affects the process of FAox differently, resulting in specific adaptions that influence endurance exercise performance. Endurance training, specifically long duration (>2 h) facilitate adaptations that alter both the origin of FAs and FAox rate. Additionally, the influence of sex and nutrition on FAox are discussed. Finally, the role of FAox in the improvement of performance during endurance training is discussed.

Magnetic tunnel junctions utilizing diamond-like carbon tunnel barriers

NASA Astrophysics Data System (ADS)

Cadieu, F. J.; Chen, Li; Li, Biao

2002-05-01

We have devised a method whereby thin particulate-free diamond-like carbon films can be made with good adhesion onto even room-temperature substrates. The method employs a filtered ionized carbon beam created by the vacuum impact of a high-energy, approximately 1 J per pulse, 248 nm excimer laser onto a carbon target. The resultant deposition beam can be steered and deflected by magnetic and electric fields to paint a specific substrate area. An important aspect of this deposition method is that the resultant films are particulate free and formed only as the result of atomic species impact. The vast majority of magnetic tunnel junctions utilizing thin metallic magnetic films have employed a thin oxidized layer of aluminum to form the tunnel barrier. This has presented reproducibility problems because the indicated optimal barrier thickness is only approximately 13 Å thick. Magnetic tunnel junctions utilizing Co and permalloy films made by evaporation and sputtering have been fabricated with an intervening diamond-like carbon tunnel barrier. The diamond-like carbon thickness profile has been tapered so that seven junctions with different barrier thickness can be formed at once. Magnetoresistive (MR) measurements made between successive permalloy strip ends include contributions from two junctions and from the permalloy and Co strips that act as current leads to the junctions. Magnetic tunnel junctions with thicker carbon barriers exhibit MR effects that are dominated by that of the permalloy strips. Since these tunnel barriers are formed without the need for oxygen, complete tunnel junctions can be formed with all high-vacuum processing.

Elementary budget of stag beetle larvae associated with selective utilization of nitrogen in decaying wood.

PubMed

Tanahashi, Masahiko; Ikeda, Hiroshi; Kubota, Kôhei

2018-05-03

Wood degradation by insects plays important roles for the forest matter cycling. Since wood is deficient in nitrogen compared to the insect body, wood-feeding insects need to assimilate the nitrogen selectively and discard an excess carbon. Such a stoichiometric imbalance between food and body will cause high metabolic cost; therefore, wood-feeding insects may somehow alleviate the stoichiometric imbalance. Here, we investigated the carbon and nitrogen budgets of the larvae of stag beetle, Dorcus rectus, which feed on decaying wood. Assimilation efficiency of ingested wood was 22%, and those values based on the carbon and nitrogen were 27 and 45%, respectively, suggesting the selective digestion of nitrogen in wood. Element-based gross growth efficiency was much higher for nitrogen (45%) than for carbon (3%). As a result, the larvae released 24% of the ingested carbon as volatile, whereas almost no gaseous exchange was observed for nitrogen. Moreover, solubility-based elementary analysis revealed that the larvae mainly utilized alkaline-soluble-water-insoluble fraction of wood, which is rich in nitrogen. Actually, the midgut of the larvae was highly alkaline (pH 10.3). Stag beetle larvae are known to exhibit coprophagy, and here we also confirmed that alkaline-soluble-water-insoluble nitrogen increased again from fresh feces to old feces in the field. Stable isotope analysis suggested the utilization of aerial nitrogen by larvae; however, its actual contribution is still disputable. Those results suggest that D. rectus larvae selectively utilize alkaline-soluble nitrogenous substrates by using their highly alkaline midgut, and perhaps associate with microbes that enhance the nitrogen recycling in feces.

Elementary budget of stag beetle larvae associated with selective utilization of nitrogen in decaying wood

NASA Astrophysics Data System (ADS)

Tanahashi, Masahiko; Ikeda, Hiroshi; Kubota, Kôhei

2018-06-01

Wood degradation by insects plays important roles for the forest matter cycling. Since wood is deficient in nitrogen compared to the insect body, wood-feeding insects need to assimilate the nitrogen selectively and discard an excess carbon. Such a stoichiometric imbalance between food and body will cause high metabolic cost; therefore, wood-feeding insects may somehow alleviate the stoichiometric imbalance. Here, we investigated the carbon and nitrogen budgets of the larvae of stag beetle, Dorcus rectus, which feed on decaying wood. Assimilation efficiency of ingested wood was 22%, and those values based on the carbon and nitrogen were 27 and 45%, respectively, suggesting the selective digestion of nitrogen in wood. Element-based gross growth efficiency was much higher for nitrogen (45%) than for carbon (3%). As a result, the larvae released 24% of the ingested carbon as volatile, whereas almost no gaseous exchange was observed for nitrogen. Moreover, solubility-based elementary analysis revealed that the larvae mainly utilized alkaline-soluble-water-insoluble fraction of wood, which is rich in nitrogen. Actually, the midgut of the larvae was highly alkaline (pH 10.3). Stag beetle larvae are known to exhibit coprophagy, and here we also confirmed that alkaline-soluble-water-insoluble nitrogen increased again from fresh feces to old feces in the field. Stable isotope analysis suggested the utilization of aerial nitrogen by larvae; however, its actual contribution is still disputable. Those results suggest that D. rectus larvae selectively utilize alkaline-soluble nitrogenous substrates by using their highly alkaline midgut, and perhaps associate with microbes that enhance the nitrogen recycling in feces.

Utilization of lignite power generation residues for the production of lightweight aggregates.

PubMed

Anagnostopoulos, Iason M; Stivanakis, Victor E

2009-04-15

A novel process is proposed for the utilization of lignite combustion solid residues in the production of inflammable lightweight aggregates (LWA). The process consists of two stages, pelletization and sintering, and carbon contained in BA was used as the process fuel. The main residues bottom ash (BA) and fly ash (FA) from Megalopolis power plant were characterized, mixed in different proportions and treated through pelletization and sintering process. Sintering benefits from combustion of BA carbon content and the product is a hardened porous cake. The energy required for achievement of high temperatures, in the range of 1250 degrees C, was offered by carbon combustion and CO(2) evolution is responsible for porous structure formation. Selected physical properties of sintered material relevant to use as lightweight aggregates were determined, including bulk density, porosity and water absorption. Bulk density varies from 0.83 to 0.91 g/cm(3), porosity varies from 60% to 64% and water absorption varies from 66% to 80%. LWA formed is used for the production of lightweight aggregate concrete (LWAC). Thermal conductivity coefficient varies from 0.25 to 0.37 W/mK (lower than maximum limit 0.43 W/mK) and compressive strength varies from 19 to 23 MPa (higher than minimum limit 17 MPa). The results indicate that sintering of lignite combustion residues is an efficient method of utilization of carbon containing BA and production of LWA for structural and insulating purposes. Carbon content of BA is a key factor in LWA production. Finally, this research work comprises the first proposed application for utilization of BA in Greece.

[Calculating the optimum size of a hemodialysis unit based on infrastructure potential].

PubMed

Avila-Palomares, Paula; López-Cervantes, Malaquías; Durán-Arenas, Luis

2010-01-01

To estimate the optimum size for hemodialysis units to maximize production given capital constraints. A national study in Mexico was conducted in 2009. Three possible methods for estimating a units optimum size were analyzed: hemodialysis services production under monopolistic market, under a perfect competitive market and production maximization given capital constraints. The third method was considered best based on the assumptions made in this paper; an optimal size unit should have 16 dialyzers (15 active and one back up dialyzer) and a purifier system able to supply all. It also requires one nephrologist, five nurses per shift, considering four shifts per day. Empirical evidence shows serious inefficiencies in the operation of units throughout the country. Most units fail to maximize production due to not fully utilizing equipment and personnel, particularly their water purifier potential which happens to be the most expensive asset for these units.

On Reverse Stackelberg Game and Optimal Mean Field Control for a Large Population of Thermostatically Controlled Loads

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

Li, Sen; Zhang, Wei; Lian, Jianming

This paper studies a multi-stage pricing problem for a large population of thermostatically controlled loads. The problem is formulated as a reverse Stackelberg game that involves a mean field game in the hierarchy of decision making. In particular, in the higher level, a coordinator needs to design a pricing function to motivate individual agents to maximize the social welfare. In the lower level, the individual utility maximization problem of each agent forms a mean field game coupled through the pricing function that depends on the average of the population control/state. We derive the solution to the reverse Stackelberg game bymore » connecting it to a team problem and the competitive equilibrium, and we show that this solution corresponds to the optimal mean field control that maximizes the social welfare. Realistic simulations are presented to validate the proposed methods.« less

Wireless Sensor Network-Based Service Provisioning by a Brokering Platform

PubMed Central

Guijarro, Luis; Pla, Vicent; Vidal, Jose R.; Naldi, Maurizio; Mahmoodi, Toktam

2017-01-01

This paper proposes a business model for providing services based on the Internet of Things through a platform that intermediates between human users and Wireless Sensor Networks (WSNs). The platform seeks to maximize its profit through posting both the price charged to each user and the price paid to each WSN. A complete analysis of the profit maximization problem is performed in this paper. We show that the service provider maximizes its profit by incentivizing all users and all Wireless Sensor Infrastructure Providers (WSIPs) to join the platform. This is true not only when the number of users is high, but also when it is moderate, provided that the costs that the users bear do not trespass a cost ceiling. This cost ceiling depends on the number of WSIPs, on the value of the intrinsic value of the service and on the externality that the WSIP has on the user utility. PMID:28498347

Wireless Sensor Network-Based Service Provisioning by a Brokering Platform.

PubMed

Guijarro, Luis; Pla, Vicent; Vidal, Jose R; Naldi, Maurizio; Mahmoodi, Toktam

2017-05-12

This paper proposes a business model for providing services based on the Internet of Things through a platform that intermediates between human users and Wireless Sensor Networks (WSNs). The platform seeks to maximize its profit through posting both the price charged to each user and the price paid to each WSN. A complete analysis of the profit maximization problem is performed in this paper. We show that the service provider maximizes its profit by incentivizing all users and all Wireless Sensor Infrastructure Providers (WSIPs) to join the platform. This is true not only when the number of users is high, but also when it is moderate, provided that the costs that the users bear do not trespass a cost ceiling. This cost ceiling depends on the number of WSIPs, on the value of the intrinsic value of the service and on the externality that the WSIP has on the user utility.

A research on service quality decision-making of Chinese communications industry based on quantum game

NASA Astrophysics Data System (ADS)

Zhang, Cuihua; Xing, Peng

2015-08-01

In recent years, Chinese service industry is developing rapidly. Compared with developed countries, service quality should be the bottleneck for Chinese service industry. On the background of three major telecommunications service providers in China, the functions of customer perceived utilities are established. With the goal of consumer's perceived utility maximization, the classic Nash equilibrium solution and quantum equilibrium solution are obtained. Then a numerical example is studied and the changing trend of service quality and customer perceived utility is further analyzed by the influence of the entanglement operator. Finally, it is proved that quantum game solution is better than Nash equilibrium solution.

Racial and Ethnic Differences in the Utilization of Prayer and Clergy Counseling by Infertile US Women Desiring Pregnancy.

PubMed

Collins, Stephen C; Kim, Soorin; Chan, Esther

2017-11-29

Religion can have a significant influence on the experience of infertility. However, it is unclear how many US women turn to religion when facing infertility. Here, we examine the utilization of prayer and clergy counsel among a nationally representative sample of 1062 infertile US women. Prayer was used by 74.8% of the participants, and clergy counsel was the most common formal support system utilized. Both prayer and clergy counsel were significantly more common among black and Hispanic women. Healthcare providers should acknowledge the spiritual needs of their infertile patients and ally with clergy when possible to provide maximally effective care.

Rediscovering Acetate Metabolism: Its Potential Sources and Utilization for Biobased Transformation into Value-Added Chemicals.

PubMed

Lim, Hyun Gyu; Lee, Ji Hoon; Noh, Myung Hyun; Jung, Gyoo Yeol

2018-04-25

One of the great advantages of microbial fermentation is the capacity to convert various carbon compounds into value-added chemicals. In this regard, there have been many efforts to engineer microorganisms to facilitate utilization of abundant carbon sources. Recently, the potential of acetate as a feedstock has been discovered; efforts have been made to produce various biochemicals from acetate based on understanding of its metabolism. In this review, we discuss the potential sources of acetate and summarized the recent progress to improve acetate utilization with microorganisms. Furthermore, we also describe representative studies that engineered microorganisms for the production of biochemicals from acetate.

Measuring Carbon Monoxide in Auto Exhaust by Gas Chromatography.

ERIC Educational Resources Information Center

Jaffe, Dan; Herndon, Scott

1995-01-01

Presents a simple and reliable technique using commonly available equipment for monitoring carbon monoxide in automobile exhaust. The experiment utilizes a gas chromatograph and a thermal conductivity detector (TCD). (DDR)

Strength Enhancement and Application Development of Carbon Foam for Thermal Protection Systems

DTIC Science & Technology

2004-09-01

to implementation was the inherent weakness and friability of the carbon foams. Under a MDA funded SBIR program, Ceramic Composites Inc . has...there are two approaches under consideration for utilizing carbon foams. Allcomp Inc.iii, Materials and Electrochemical Researchiv, Touchstonev...Ceramic Composites Inc . (CCI) elected to take an alternative approach to enhancing the strength of carbon foam. For our evaluation, two polymeric pre

A toy terrestrial carbon flow model

NASA Technical Reports Server (NTRS)

Parton, William J.; Running, Steven W.; Walker, Brian

1992-01-01

A generalized carbon flow model for the major terrestrial ecosystems of the world is reported. The model is a simplification of the Century model and the Forest-Biogeochemical model. Topics covered include plant production, decomposition and nutrient cycling, biomes, the utility of the carbon flow model for predicting carbon dynamics under global change, and possible applications to state-and-transition models and environmentally driven global vegetation models.

Utilizing the School Health Index to Foster University and Community Engagement

ERIC Educational Resources Information Center

King, Kristi McClary

2010-01-01

A Coordinated School Health Program maximizes a school's positive interaction among health education, physical education, health services, nutrition services, counseling/psychological/social services, health school environment, health promotion for staff, and family and community involvement. The purpose of this semester project is for…

Releases: Is There Still a Place for Their Use by Colleges and Universities?

ERIC Educational Resources Information Center

Connell, Mary Ann; Savage, Frederick G.

2003-01-01

Analyzes the legal principles, facts, and circumstances that govern decisions of courts regarding the validity of written releases, and provides practical advice to higher education lawyers and administrators as they evaluate the utility of releases and seek to maximize their benefit. (EV)

The future of transportation planning : dynamic travel behavior analyses based on stochastic decision-making styles : final report.

DOT National Transportation Integrated Search

2003-08-01

Over the past half-century, the progress of travel behavior research and travel demand forecasting has been spear : headed and continuously propelled by the micro-economic theories, specifically utility maximization. There is no : denial that the tra...

On the Teaching of Portfolio Theory.

ERIC Educational Resources Information Center

Biederman, Daniel K.

1992-01-01

Demonstrates how a simple portfolio problem expressed explicitly as an expected utility maximization problem can be used to instruct students in portfolio theory. Discusses risk aversion, decision making under uncertainty, and the limitations of the traditional mean variance approach. Suggests students may develop a greater appreciation of general…

Program Monitoring: Problems and Cases.

ERIC Educational Resources Information Center

Lundin, Edward; Welty, Gordon

Designed as the major component of a comprehensive model of educational management, a behavioral model of decision making is presented that approximates the synoptic model of neoclassical economic theory. The synoptic model defines all possible alternatives and provides a basis for choosing that alternative which maximizes expected utility. The…

A Bayesian Approach to Interactive Retrieval

ERIC Educational Resources Information Center

Tague, Jean M.

1973-01-01

A probabilistic model for interactive retrieval is presented. Bayesian statistical decision theory principles are applied: use of prior and sample information about the relationship of document descriptions to query relevance; maximization of expected value of a utility function, to the problem of optimally restructuring search strategies in an…

Innovative Conference Curriculum: Maximizing Learning and Professionalism

ERIC Educational Resources Information Center

Hyland, Nancy; Kranzow, Jeannine

2012-01-01

This action research study evaluated the potential of an innovative curriculum to move 73 graduate students toward professional development. The curriculum was grounded in the professional conference and utilized the motivation and expertise of conference presenters. This innovation required students to be more independent, act as a critical…

Method of optimizing performance of Rankine cycle power plants

DOEpatents

Pope, William L.; Pines, Howard S.; Doyle, Padraic A.; Silvester, Lenard F.

1982-01-01

A method for efficiently operating a Rankine cycle power plant (10) to maximize fuel utilization efficiency or energy conversion efficiency or minimize costs by selecting a turbine (22) fluid inlet state which is substantially in the area adjacent and including the transposed critical temperature line (46).

Making It Stick

ERIC Educational Resources Information Center

Ewers, Justin

2009-01-01

It seems to happen every day. A meeting is called to outline a new strategy or sales plan. Down go the lights and up goes the PowerPoint. Strange phrases appear--"unlocking shareholder value," "technology-focused innovation," "maximizing utility." Lists of numbers come and go. Bullet point by bullet point, the…

Planning and managing market research: Electric utility market research monograph series: Monograph 1

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

Whitelaw, R.W.

1987-01-01

The market research techniques available now to the electric utility industry have evolved over the last thirty years into a set of sophisticated tools that permit complex behavioral analyses that earlier had been impossible. The marketing questions facing the electric utility industry now are commensurately more complex than ever before. This document was undertaken to present the tools and techniques needed to start or improve the usefulness of market research activities within electric utilities. It describes proven planning and management techniques as well as decision criteria for structuring effective market research functions for each utility's particular needs. The monograph establishesmore » the parameters of sound utility market research given trade-offs between highly centralized or decentralized organizations, research focus, involvement in decision making, and personnel and management skills necessary to maximize the effectiveness of the structure chosen.« less

Rolling contact fatigue of low hardness steel for slewing ring application

NASA Astrophysics Data System (ADS)

Knuth, Jason A.

This thesis discusses the rolling contact fatigue of steel utilized in anti-friction bearings, also referred to as slewing bearings. These slewing bearings are utilized in cranes, excavators, wind turbines and other similar applications. Five materials composed of two different material types were tested. The two material types were high carbon steel and medium carbon alloy steel. The test specimens were processed from forged rolled rings. Two machines were evaluated a ZF-RCF and 3-Ball test machine. The evaluation was to determine which machine can best simulate the application in which the slewing bearing is utilized. Initially, each specimen will be pretested to determine the appropriate testing direction from within the forged rolled rings. Pretesting is needed in order to establish consistent failure modes between samples. The primary goal of the test is to understand the life differences and failure modes between high carbon steel and medium carbon alloy steel. The high carbon steel ring was cut into two sections, one of which was stress relieved and the other was quenched and tempered. The medium carbon alloy steel was cut into three sections, all of which were quenched and tempered to different hardness levels. The test program was dynamically adjusted based upon the previous sample's life and load. An S-N curve was then established from the 5 materials tested at two target loads. The samples were run until the first sign of a crack was detected by an eddy current. At the completion of the rolling contact test, select sample's microstructure was evaluated for crack initiation location. The selected samples were divided into four groups which represent different maximum shear stress levels. These samples displayed indications of material deformation in which the high carbon steel experienced an increased amount of cold work when compared to medium carbon alloy steel. The life of the high carbon steel was nearly equivalent to the expected life of the medium carbon alloy. The work hardening of the high carbon steel increased the surface hardness that exceeded the medium carbon alloy steel surface hardness.

Filtration-guided assembly for patterning one-dimensional nanostructures

NASA Astrophysics Data System (ADS)

Zhang, Yaozhong; Wang, Chuan; Yeom, Junghoon

2017-04-01

Tremendous progress has been made in synthesizing various types of one-dimensional (1D) nanostructures (NSs), such as nanotubes and nanowires, but some technical challenges still remain in the deterministic assembly of the solution-processed 1D NSs for device integration. In this work we investigate a scalable yet inexpensive nanomaterial assembly method, namely filtration-guided assembly (FGA), to place nanomaterials into desired locations as either an individual entity or ensembles, and form functional devices. FGA not only addresses the assembly challenges but also encompasses the notion of green nanomanufacturing, maximally utilizing nanomaterials and eliminating a waste stream of nanomaterials into the environment. FGA utilizes selective filtration of 1D NSs through the open windows on the nanoporous filter membrane whose surface is patterned by a polymer mask for guiding the 1D NS deposition. The modified soft-lithographic technique called blanket transfer (BT) is employed to create the various photoresist patterns of sub-10-micron resolution on the nanoporous filter membrane like mixed cellulose acetate. We use single-walled carbon nanotubes (SWCNTs) as a model 1D NS and demonstrate the fabrication of an array pattern of homogeneous 1D NS network films over an area of 20 cm2 within 10 min. The FGA-patterned SWCNT network films are transferred onto the substrate using the adhesive-based transfer technique, and show the highly uniform film thickness and resistance measurements across the entire substrate. Finally, the electrical performance of the back-gated transistors made from the FGA and transfer method of 95% pure SWCNTs is demonstrated.

Filtration-guided assembly for patterning one-dimensional nanostructures.

PubMed

Zhang, Yaozhong; Wang, Chuan; Yeom, Junghoon

2017-04-07

Tremendous progress has been made in synthesizing various types of one-dimensional (1D) nanostructures (NSs), such as nanotubes and nanowires, but some technical challenges still remain in the deterministic assembly of the solution-processed 1D NSs for device integration. In this work we investigate a scalable yet inexpensive nanomaterial assembly method, namely filtration-guided assembly (FGA), to place nanomaterials into desired locations as either an individual entity or ensembles, and form functional devices. FGA not only addresses the assembly challenges but also encompasses the notion of green nanomanufacturing, maximally utilizing nanomaterials and eliminating a waste stream of nanomaterials into the environment. FGA utilizes selective filtration of 1D NSs through the open windows on the nanoporous filter membrane whose surface is patterned by a polymer mask for guiding the 1D NS deposition. The modified soft-lithographic technique called blanket transfer (BT) is employed to create the various photoresist patterns of sub-10-micron resolution on the nanoporous filter membrane like mixed cellulose acetate. We use single-walled carbon nanotubes (SWCNTs) as a model 1D NS and demonstrate the fabrication of an array pattern of homogeneous 1D NS network films over an area of 20 cm 2 within 10 min. The FGA-patterned SWCNT network films are transferred onto the substrate using the adhesive-based transfer technique, and show the highly uniform film thickness and resistance measurements across the entire substrate. Finally, the electrical performance of the back-gated transistors made from the FGA and transfer method of 95% pure SWCNTs is demonstrated.

Carbon metabolism of the cryptoendolithic microbiota from the Antarctic desert

NASA Technical Reports Server (NTRS)

Vestal, J. R.; Friedmann, E. I. (Principal Investigator)

1988-01-01

The carbon metabolism of the cryptoendolithic microbiota of sandstones from the Ross Desert of Antarctica was studied in situ and in vitro. Organic and inorganic carbon compounds were metabolized by the microbiota, with bicarbonate incorporation into community lipids occurring primarily in the light. Light intensity affected the photometabolism of carbon with a photosynthesis-intensity response optimum at about 200 to 300 micromoles of photons per m2 per s. Photosynthesis was also affected by temperature, with a minimum activity at -5 degrees C, an optimum activity at 15 degrees C, and complete inhibition at 35 degrees C, indicating that the cryptoendolithic community was psychrophilic. The primary source of CO2 for photosynthesis in situ was the atmosphere. CO2 may also be photometabolized by using the carbon produced from respiration within the endolithic community. Photosynthesis occurred maximally when the microbiota was wet with liquid water and to a lesser extent in a humid atmosphere. This simple microbial community, therefore, exists under extremes of water, light, and temperature stress which affect and control its metabolism.

Abiotic influences on bicarbonate use in the giant kelp, Macrocystis pyrifera, in the Monterey Bay.

PubMed

Drobnitch, Sarah Tepler; Nickols, Kerry; Edwards, Matthew

2017-02-01

In the Monterey Bay region of central California, the giant kelp Macrocystis pyrifera experiences broad fluctuations in wave forces, temperature, light availability, nutrient availability, and seawater carbonate chemistry, all of which may impact their productivity. In particular, current velocities and light intensity may strongly regulate the supply and demand of inorganic carbon (Ci) as substrates for photosynthesis. Macrocystis pyrifera can acquire and utilize both CO 2 and bicarbonate (HCO 3 - ) as Ci substrates for photosynthesis and growth. Given the variability in carbon delivery (due to current velocities and varying [DIC]) and demand (in the form of saturating irradiance), we hypothesized that the proportion of CO 2 and bicarbonate utilized is not constant for M. pyrifera, but a variable function of their fluctuating environment. We further hypothesized that populations acclimated to different wave exposure and irradiance habitats would display different patterns of bicarbonate uptake. To test these hypotheses, we carried out oxygen evolution trials in the laboratory to measure the proportion of bicarbonate utilized by M. pyrifera via external CA under an orthogonal cross of velocity, irradiance, and acclimation treatments. Our Monterey Bay populations of M. pyrifera exhibited proportionally higher external bicarbonate utilization in high irradiance and high flow velocity conditions than in sub-saturating irradiance or low flow velocity conditions. However, there was no significant difference in proportional bicarbonate use between deep blades and canopy blades, nor between individuals from wave-exposed versus wave-protected sites. This study contributes a new field-oriented perspective on the abiotic controls of carbon utilization physiology in macroalgae. © 2016 Phycological Society of America.

Carbon deposition thresholds on nickel-based solid oxide fuel cell anodes II. Steam:carbon ratio and current density

NASA Astrophysics Data System (ADS)

Kuhn, J.; Kesler, O.

2015-03-01

For the second part of a two part publication, coking thresholds with respect to molar steam:carbon ratio (SC) and current density in nickel-based solid oxide fuel cells were determined. Anode-supported button cell samples were exposed to 2-component and 5-component gas mixtures with 1 ≤ SC ≤ 2 and zero fuel utilization for 10 h, followed by measurement of the resulting carbon mass. The effect of current density was explored by measuring carbon mass under conditions known to be prone to coking while increasing the current density until the cell was carbon-free. The SC coking thresholds were measured to be ∼1.04 and ∼1.18 at 600 and 700 °C, respectively. Current density experiments validated the thresholds measured with respect to fuel utilization and steam:carbon ratio. Coking thresholds at 600 °C could be predicted with thermodynamic equilibrium calculations when the Gibbs free energy of carbon was appropriately modified. Here, the Gibbs free energy of carbon on nickel-based anode support cermets was measured to be -6.91 ± 0.08 kJ mol-1. The results of this two part publication show that thermodynamic equilibrium calculations with appropriate modification to the Gibbs free energy of solid-phase carbon can be used to predict coking thresholds on nickel-based anodes at 600-700 °C.

NASA/GSFC Research Activities for the Global Ocean Carbon Cycle: A Prospectus for the 21st Century

NASA Technical Reports Server (NTRS)

Gregg, W. W.; Behrenfield, M. J.; Hoge, F. E.; Esaias, W. E.; Huang, N. E.; Long, S. R.; McClain, C. R.

2000-01-01

There are increasing concerns that anthropogenic inputs of carbon dioxide into the Earth system have the potential for climate change. In response to these concerns, the GSFC Laboratory for Hydrospheric Processes has formed the Ocean Carbon Science Team (OCST) to contribute to greater understanding of the global ocean carbon cycle. The overall goals of the OCST are to: 1) detect changes in biological components of the ocean carbon cycle through remote sensing of biooptical properties, 2) refine understanding of ocean carbon uptake and sequestration through application of basic research results, new satellite algorithms, and improved model parameterizations, 3) develop and implement new sensors providing critical missing environmental information related to the oceanic carbon cycle and the flux of CO2 across the air-sea interface. The specific objectives of the OCST are to: 1) establish a 20-year time series of ocean color, 2) develop new remote sensing technologies, 3) validate ocean remote sensing observations, 4) conduct ocean carbon cycle scientific investigations directly related to remote sensing data, emphasizing physiological, empirical and coupled physical/biological models, satellite algorithm development and improvement, and analysis of satellite data sets. These research and mission objectives are intended to improve our understanding of global ocean carbon cycling and contribute to national goals by maximizing the use of remote sensing data.

One-step sub-10 μm patterning of carbon-nanotube thin films for transparent conductor applications.

PubMed

Fukaya, Norihiro; Kim, Dong Young; Kishimoto, Shigeru; Noda, Suguru; Ohno, Yutaka

2014-04-22

We propose a technique for one-step micropatterning of as-grown carbon-nanotube films on a plastic substrate with sub-10 μm resolution on the basis of the dry transfer process. By utilizing this technique, we demonstrated the novel high-performance flexible carbon-nanotube transparent conductive film with a microgrid structure, which enabled improvement of the performance over the trade-off between the sheet resistance and transmittance of a conventional uniform carbon-nanotube film. The sheet resistance was reduced by 46% at its maximum by adding the microgrid, leading to a value of 53 Ω/sq at a transmittance of 80%. We also demonstrated easy fabrication of multitouch projected capacitive sensors with 12 × 12 electrodes. The technique is quite promising for energy-saving production of transparent conductor devices with 100% material utilization.

Maximizing profitability in a hospital outpatient pharmacy.

PubMed

Jorgenson, J A; Kilarski, J W; Malatestinic, W N; Rudy, T A

1989-07-01

This paper describes the strategies employed to increase the profitability of an existing ambulatory pharmacy operated by the hospital. Methods to generate new revenue including implementation of a home parenteral therapy program, a home enteral therapy program, a durable medical equipment service, and home care disposable sales are described. Programs to maximize existing revenue sources such as increasing the capture rate on discharge prescriptions, increasing "walk-in" prescription traffic and increasing HMO prescription volumes are discussed. A method utilized to reduce drug expenditures is also presented. By minimizing expenses and increasing the revenues for the ambulatory pharmacy operation, net profit increased from +26,000 to over +140,000 in one year.