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Sample records for optimal solvent cycle

  1. Optimization of data life cycles

    NASA Astrophysics Data System (ADS)

    Jung, C.; Gasthuber, M.; Giesler, A.; Hardt, M.; Meyer, J.; Rigoll, F.; Schwarz, K.; Stotzka, R.; Streit, A.

    2014-06-01

    Data play a central role in most fields of science. In recent years, the amount of data from experiment, observation, and simulation has increased rapidly and data complexity has grown. Also, communities and shared storage have become geographically more distributed. Therefore, methods and techniques applied to scientific data need to be revised and partially be replaced, while keeping the community-specific needs in focus. The German Helmholtz Association project "Large Scale Data Management and Analysis" (LSDMA) aims to maximize the efficiency of data life cycles in different research areas, ranging from high energy physics to systems biology. In its five Data Life Cycle Labs (DLCLs), data experts closely collaborate with the communities in joint research and development to optimize the respective data life cycle. In addition, the Data Services Integration Team (DSIT) provides data analysis tools and services which are common to several DLCLs. This paper describes the various activities within LSDMA and focuses on the work performed in the DLCLs.

  2. On optimal velocity during cycling.

    PubMed

    Maroński, R

    1994-02-01

    This paper focuses on the solution of two problems related to cycling. One is to determine the velocity as a function of distance which minimizes the cyclist's energy expenditure in covering a given distance in a set time. The other is to determine the velocity as a function of the distance which minimizes time for fixed energy expenditure. To solve these problems, an equation of motion for the cyclist riding over arbitrary terrain is written using Newton's second law. This equation is used to evaluate either energy expenditure or time, and the minimization problems are solved using an optimal control formulation in conjunction with the method of Miele [Optimization Techniques with Applications to Aerospace Systems, pp. 69-98 (1962) Academic Press, New York]. Solutions to both optimal control problems are the same. The solutions are illustrated through two examples. In one example where the relative wind velocity is zero, the optimal cruising velocity is constant regardless of terrain. In the second, where the relative wind velocity fluctuates, the optimal cruising velocity varies.

  3. Multi-cycle boiling water reactor fuel cycle optimization

    SciTech Connect

    Ottinger, K.; Maldonado, G.I.

    2013-07-01

    In this work a new computer code, BWROPT (Boiling Water Reactor Optimization), is presented. BWROPT uses the Parallel Simulated Annealing (PSA) algorithm to solve the out-of-core optimization problem coupled with an in-core optimization that determines the optimum fuel loading pattern. However it uses a Haling power profile for the depletion instead of optimizing the operating strategy. The result of this optimization is the optimum new fuel inventory and the core loading pattern for the first cycle considered in the optimization. Several changes were made to the optimization algorithm with respect to other nuclear fuel cycle optimization codes that use PSA. Instead of using constant sampling probabilities for the solution perturbation types throughout the optimization as is usually done in PSA optimizations the sampling probabilities are varied to get a better solution and/or decrease runtime. The new fuel types available for use can be sorted into an array based on any number of parameters so that each parameter can be incremented or decremented, which allows for more precise fuel type selection compared to random sampling. Also, the results are sorted by the new fuel inventory of the first cycle for ease of comparing alternative solutions. (authors)

  4. Carboxymethylation of Cassava Starch in Different Solvents and Solvent-Water Mixtures: Optimization of Reaction Conditions

    NASA Astrophysics Data System (ADS)

    Nwokocha, Louis M.; Ogunmola, Gabiel B.

    The influence of reaction medium on carboxymethylation process was investigated by treating cassava starch with sodium monochloroacetate in different solvents and solvent-water mixtures under alkaline conditions. The amount of carboxyl groups introduced into the starch moiety was determined titrimetrically and used to calculate the Degree of Substitution (DS) and Reaction Efficiency (RE). The results showed that carboxymethylation is significantly affected by the nature of reaction medium at p<0.05. Carboxymethylation in different solvent-water mixtures showed that aqueous 80% n-propanol offered the best medium for carboxymethylation. Optimization of reaction conditions in aqueous 80% n-propanol showed that the best condition for carboxymethylation was at starch-liquor ratio of 1:3, NaOH/reagent molar ratio of 4.0 and reagent-starch molar ratio of 0.35. An increase in temperature was required to effect the reaction at shorter time. At 55°C the highest values of DS and RE achieved in 0.5 h would require three hours to achieve the same values of DS and RE at 45°C.

  5. Controlling Actinide Hydration in Mixed Solvent Systems: Towards Tunable Solvent Systems to Close the Fuel Cycle

    SciTech Connect

    Clark, Sue B.

    2016-10-31

    The goal of this project has been to define the extent of hydration the f-elements and other cations in mixed solvent electrolyte systems. Methanol-water and other mixed solvent systems have been studied, where the solvent dielectric constant was varied systematically. Thermodynamic and spectroscopic studies provide details concerning the energetics of complexation and other reactions of these cations. This information has also been used to advance new understanding of the behavior of these cations in a variety of systems, ranging from environmental studies, chromatographic approaches, and ionization processes for mass spectrometry.

  6. Life Cycle Assessment of an Ionic LIquid versus Traditional Solvents and Their Applications

    EPA Science Inventory

    Ionic liquids (ILs) have been claimed as "greener" replacements to traditional solvents. HOwever, the environmental impacts of the life cycle phases including the making of ILs, their application, separation, etc., and comparison with alternative methods have not been studied. Su...

  7. Universal optimal working cycles of molecular motors.

    PubMed

    Efremov, Artem; Wang, Zhisong

    2011-04-07

    Molecular motors capable of directional track-walking or rotation are abundant in living cells, and inspire the emerging field of artificial nanomotors. Some biomotors can convert 90% of free energy from chemical fuels into usable mechanical work, and the same motors still maintain a speed sufficient for cellular functions. This study exposed a new regime of universal optimization that amounts to a thermodynamically best working regime for molecular motors but is unfamiliar in macroscopic engines. For the ideal case of zero energy dissipation, the universally optimized working cycle for molecular motors is infinitely slow like Carnot cycle for heat engines. But when a small amount of energy dissipation reduces energy efficiency linearly from 100%, the speed is recovered exponentially due to Boltzmann's law. Experimental data on a major biomotor (kinesin) suggest that the regime of universal optimization has been largely approached in living cells, underpinning the extreme efficiency-speed trade-off in biomotors. The universal optimization and its practical approachability are unique thermodynamic advantages of molecular systems over macroscopic engines in facilitating motor functions. The findings have important implications for the natural evolution of biomotors as well as the development of artificial counterparts.

  8. Optimization of in-cell accelerated solvent extraction technique for the determination of organochlorine pesticides in river sediments.

    PubMed

    Duodu, Godfred Odame; Goonetilleke, Ashantha; Ayoko, Godwin A

    2016-04-01

    Organochlorine pesticides (OCPs) are ubiquitous environmental contaminants with adverse impacts on aquatic biota, wildlife and human health even at low concentrations. However, conventional methods for their determination in river sediments are resource intensive. This paper presents an approach that is rapid and also reliable for the detection of OCPs. Accelerated Solvent Extraction (ASE) with in-cell silica gel clean-up followed by Triple Quadrupole Gas Chromatograph Mass Spectrometry (GCMS/MS) was used to recover OCPs from sediment samples. Variables such as temperature, solvent ratio, adsorbent mass and extraction cycle were evaluated and optimized for the extraction. With the exception of Aldrin, which was unaffected by any of the variables evaluated, the recovery of OCPs from sediment samples was largely influenced by solvent ratio and adsorbent mass and, to some extent, the number of cycles and temperature. The optimized conditions for OCPs extraction in sediment with good recoveries were determined to be 4 cycles, 4.5 g of silica gel, 105 °C, and 4:3 v/v DCM: hexane mixture. With the exception of two compounds (α-BHC and Aldrin) whose recoveries were low (59.73 and 47.66% respectively), the recovery of the other pesticides were in the range 85.35-117.97% with precision <10% RSD. The method developed significantly reduces sample preparation time, the amount of solvent used, matrix interference, and is highly sensitive and selective.

  9. Toxic heavy metals: materials cycle optimization.

    PubMed Central

    Ayres, R U

    1992-01-01

    Long-term ecological sustainability is incompatible with an open materials cycle. The toxic heavy metals (arsenic, cadmium, chromium, copper, lead, mercury, silver, uranium/plutonium, zinc) exemplify the problem. These metals are being mobilized and dispersed into the environment by industrial activity at a rate far higher than by natural processes. Apart from losses to the environment resulting from mine wastes and primary processing, many of these metals are utilized in products that are inherently dissipative. Examples of such uses include fuels, lubricants, solvents, fire retardants, stabilizers, flocculants, pigments, biocides, and preservatives. To close the materials cycle, it will be necessary to accomplish two things. The first is to ban or otherwise discourage (e.g., by means of high severance taxes on virgin materials) dissipative uses of the above type. The second is to increase the efficiency of recycling of those materials that are not replaceable in principle. Here, also, economic instruments (such as returnable deposits) can be effective in some cases. A systems view of the problem is essential to assess the cost and effectiveness of alternative strategies. PMID:11607259

  10. Environmental analysis of the life cycle emissions of 2-methyl tetrahydrofuran solvent manufactured from renewable resources.

    PubMed

    Slater, C Stewart; Savelski, Mariano J; Hitchcock, David; Cavanagh, Eduardo J

    2016-01-01

    An environmental analysis has been conducted to determine the cradle to gate life cycle emissions to manufacture the green solvent, 2-methyl tetrahydrofuran. The solvent is considered a greener chemical since it can be manufactured from renewable resources with a lower life cycle footprint. Analyses have been performed using different methods to show greenness in both its production and industrial use. This solvent can potentially be substituted for other ether and chlorinated solvents commonly used in organometallic and biphasic reactions steps in pharmaceutical and fine chemical syntheses. The 2-methyl tetrahydrofuran made from renewable agricultural by-products is marketed by Penn A Kem under the name ecoMeTHF™. The starting material, 2-furfuraldehyde (furfural), is produced from corn cob waste by converting the available pentosans by acid hydrolysis. An evaluation of each step in the process was necessary to determine the overall life cycle and specific CO2 emissions for each raw material/intermediate produced. Allocation of credits for CO2 from the incineration of solvents made from renewable feedstocks significantly reduced the overall carbon footprint. Using this approach, the overall life cycle emissions for production of 1 kg of ecoMeTHF™ were determined to be 0.191 kg, including 0.150 kg of CO2. Life cycle emissions generated from raw material manufacture represents the majority of the overall environmental impact. Our evaluation shows that using 2-methyl tetrahydrofuran in an industrial scenario results in a 97% reduction in emissions, when compared to typically used solvents such as tetrahydrofuran, made through a conventional chemical route.

  11. Density Changes in the Optimized CSSX Solvent System

    SciTech Connect

    Lee, D.D.

    2002-11-25

    Density increases in caustic-side solvent extraction (CSSX) solvent have been observed in separate experimental programs performed by different groups of researchers. Such changes indicate a change in chemical composition. Increased density adversely affects separation of solvent from denser aqueous solutions present in the CSSX process. Identification and control of factors affecting solvent density are essential for design and operation of the centrifugal contactors. The goals of this research were to identify the factors affecting solvent density (composition) and to develop correlations between easily measured solvent properties (density and viscosity) and the chemical composition of the solvent, which will permit real-time determination and adjustment of the solvent composition. In evaporation experiments, virgin solvent was subjected to evaporation under quiescent conditions at 25, 35, and 45 C with continuously flowing dry air passing over the surface of the solvent. Density and viscosity were measured periodically, and chemical analysis was performed on the solvent samples. Chemical interaction tests were completed to determine if any chemical reaction takes place over extended contact time that changes the composition and/or physical properties. Solvent and simulant, solvent and strip solution, and solvent and wash solution were contacted continuously in agitated flasks. They were periodically sampled and the density measured (viscosity was also measured on some samples) and then submitted to the Chemical Sciences Division of Oak Ridge National Laboratory for analysis by nuclear magnetic resonance (NMR) spectrometry and high-performance liquid chromatography (HPLC) using the virgin solvent as the baseline. Chemical interaction tests showed that solvent densities and viscosities did not change appreciably during contact with simulant, strip, or wash solution. No effects on density and viscosity and no chemical changes in the solvent were noted within

  12. Variational Optimization of an All-Atom Implicit Solvent Force Field to Match Explicit Solvent Simulation Data

    PubMed Central

    Bottaro, Sandro; Lindorff-Larsen, Kresten; Best, Robert B.

    2013-01-01

    The development of accurate implicit solvation models with low computational cost is essential for addressing many large-scale biophysical problems. Here, we present an efficient solvation term based on a Gaussian solvent-exclusion model (EEF1) for simulations of proteins in aqueous environment, with the primary aim of having a good overlap with explicit solvent simulations, particularly for unfolded and disordered states – as would be needed for multiscale applications. In order to achieve this, we have used a recently proposed coarse-graining procedure based on minimization of an entropy-related objective function to train the model to reproduce the equilibrium distribution obtained from explicit water simulations. Via this methodology, we have optimized both a charge screening parameter and a backbone torsion term against explicit solvent simulations of an α-helical and a β-stranded peptide. The performance of the resulting effective energy function, termed EEF1-SB, is tested with respect to the properties of folded proteins, the folding of small peptides or fast-folding proteins, and NMR data for intrinsically disordered proteins. The results show that EEF1-SB provides a reasonable description of a wide range of systems, but its key advantage over other methods tested is that it captures very well the structure and dimension of disordered or weakly structured peptides. EEF1-SB is thus a computationally inexpensive (~ 10 times faster than Generalized-Born methods) and transferable approximation for treating solvent effects. PMID:24748852

  13. Regenerator optimization for Stirling cycle refrigeration II

    SciTech Connect

    Colgate, S.A.; Petschek, A.G.

    1994-07-01

    A cryogenic regenerator for a Stirling cycle is discussed using fractional loss or entropy gain as the criterion of performance. The gas losses are treated separately from heat storage medium losses. We argue that the optimum design corresponds to uniform channel flow with minimum turbulence where the gas velocity and channel width are optimized as a function of gas temperature. The maximization of heat transfer from the gas to the wall and the minimization of entropy production by friction leads to a gas flow velocity equal to sound speed times loss fraction, 1/{sigma}. This velocity and an axial thermal conductivity in the gas leads to a minimum channel width and characteristic length, L=T(dz/dT). A particular scaling of width, W{sup 2} = W{sub o}{sup 2}T{sup 1/2}, and length, L = L{sub o} T{sup {minus}1/2} leads to a design where longitudinal conduction decreases as T{sup 3/2} and the remaining two losses, transverse conduction and friction are equal and constant. The loss fraction, 1/{sigma}, must be made quite small, {approximately}(1/60) in order that the cumulative losses for a large temperature ratio like 300K to 4K, be small enough, like 20% to 40%. This is because half the entropy generated as a loss must be transported first to the cold end before returning to the hot end before being rejected. The dead volume ratio then determines the minimum frequency and with it and the pressure the necessary wall properties. The thermal properties of the channel wall must then accommodate this cyclic heat flow without substantially increasing the loss fraction. This generation of entropy in the walls is derived in terms of the wall heat capacity and thermal conductivity.

  14. Optimization of closed Brayton cycles for space power generation

    NASA Technical Reports Server (NTRS)

    Hanlon, James C.

    1992-01-01

    A development status evaluation is presented for methods that allow accurate preliminary design and optimization of closed Brayton cycle engines for space electrical power generation. The basis for such work is the Closed Cycle Engine Performance simulation code, in conjunction with the optimization code COPES/ADS; the joining of the two codes has greatly expedited the optimization process. Attention is given to a variety of other model-versatility enhancers.

  15. Optimization of Turbine Engine Cycle Analysis with Analytic Derivatives

    NASA Technical Reports Server (NTRS)

    Hearn, Tristan; Hendricks, Eric; Chin, Jeffrey; Gray, Justin; Moore, Kenneth T.

    2016-01-01

    A new engine cycle analysis tool, called Pycycle, was built using the OpenMDAO framework. Pycycle provides analytic derivatives allowing for an efficient use of gradient-based optimization methods on engine cycle models, without requiring the use of finite difference derivative approximation methods. To demonstrate this, a gradient-based design optimization was performed on a turbofan engine model. Results demonstrate very favorable performance compared to an optimization of an identical model using finite-difference approximated derivatives.

  16. Sensitivity analysis and optimization of the nuclear fuel cycle

    SciTech Connect

    Passerini, S.; Kazimi, M. S.; Shwageraus, E.

    2012-07-01

    A sensitivity study has been conducted to assess the robustness of the conclusions presented in the MIT Fuel Cycle Study. The Once Through Cycle (OTC) is considered as the base-line case, while advanced technologies with fuel recycling characterize the alternative fuel cycles. The options include limited recycling in LWRs and full recycling in fast reactors and in high conversion LWRs. Fast reactor technologies studied include both oxide and metal fueled reactors. The analysis allowed optimization of the fast reactor conversion ratio with respect to desired fuel cycle performance characteristics. The following parameters were found to significantly affect the performance of recycling technologies and their penetration over time: Capacity Factors of the fuel cycle facilities, Spent Fuel Cooling Time, Thermal Reprocessing Introduction Date, and in core and Out-of-core TRU Inventory Requirements for recycling technology. An optimization scheme of the nuclear fuel cycle is proposed. Optimization criteria and metrics of interest for different stakeholders in the fuel cycle (economics, waste management, environmental impact, etc.) are utilized for two different optimization techniques (linear and stochastic). Preliminary results covering single and multi-variable and single and multi-objective optimization demonstrate the viability of the optimization scheme. (authors)

  17. Optimizing the surface density of polyethylene glycol chains by grafting from binary solvent mixtures

    NASA Astrophysics Data System (ADS)

    Arcot, Lokanathan; Ogaki, Ryosuke; Zhang, Shuai; Meyer, Rikke L.; Kingshott, Peter

    2015-06-01

    Polyethylene glycol (PEG) brushes are very effective at controlling non-specific deposition of biological material onto surfaces, which is of paramount importance to obtaining successful outcomes in biomaterials, tissue engineered scaffolds, biosensors, filtration membranes and drug delivery devices. We report on a simple 'grafting to' approach involving binary solvent mixtures that are chosen based on Hansen's solubility parameters to optimize the solubility of PEG thereby enabling control over the graft density. The PEG thiol-gold model system enabled a thorough characterization of PEG films formed, while studies on a PEG silane-silicon system examined the versatility to be applied to any substrate-head group system by choosing an appropriate solvent pair. The ability of PEG films to resist non-specific adsorption of proteins was quantitatively assessed by full serum exposure studies and the binary solvent strategy was found to produce PEG films with optimal graft density to efficiently resist protein adsorption.

  18. Optimization of life cycle management costs

    SciTech Connect

    Banerjee, A.K.

    1994-12-31

    As can be seen from the case studies, a LCM program needs to address and integrate, in the decision process, technical, political, licensing, remaining plant life, component replacement cycles, and financial issues. As part of the LCM evaluations, existing plant programs, ongoing replacement projects, short and long-term operation and maintenance issues, and life extension strategies must be considered. The development of the LCM evaluations and the cost benefit analysis identifies critical technical and life cycle cost parameters. These {open_quotes}discoveries{close_quotes} result from the detailed and effective use of a consistent, quantifiable, and well documented methodology. The systematic development and implementation of a plant-wide LCM program provides for an integrated and structured process that leads to the most practical and effective recommendations. Through the implementation of these recommendations and cost effective decisions, the overall power production costs can be controlled and ultimately lowered.

  19. SOLVENT EXTRACTION RESEARCH AND DEVELOPMENT IN THE U.S. FUEL CYCLE PROGRAM

    SciTech Connect

    Terry A. Todd

    2011-10-01

    Treatment or processing of used nuclear fuel to recycle uranium and plutonium has historically been accomplished using the well known PUREX process. The PUREX process has been used on an industrial scale for over 60 years in the nuclear industry. Research is underway to develop advanced separation methods for the recovery of other used fuel components, such as the minor actinides (Np, Am, Cm) for possible transmutation in fast spectrum reactors, or other constituents (e.g. Cs, Sr, transition metals, lanthanides) to help facilitate effective waste management options. This paper will provide an overview of new solvent extraction processes developed for advanced nuclear fuel cycles, and summarize recent experimental results. This will include the utilization of new extractants for selective separation of target metals and new processes developed to selectively recover one or more elements from used fuel.

  20. Optimization of Turbine Engine Cycle Analysis with Analytic Derivatives

    NASA Technical Reports Server (NTRS)

    Hearn, Tristan; Hendricks, Eric; Chin, Jeffrey; Gray, Justin; Moore, Kenneth T.

    2016-01-01

    A new engine cycle analysis tool, called Pycycle, was recently built using the OpenMDAO framework. This tool uses equilibrium chemistry based thermodynamics, and provides analytic derivatives. This allows for stable and efficient use of gradient-based optimization and sensitivity analysis methods on engine cycle models, without requiring the use of finite difference derivative approximation methods. To demonstrate this, a gradient-based design optimization was performed on a multi-point turbofan engine model. Results demonstrate very favorable performance compared to an optimization of an identical model using finite-difference approximated derivatives.

  1. Regenerator optimization for Stirling cycle refrigeration

    SciTech Connect

    Colgate, S.A.; Petschek, A.G.

    1993-08-01

    A cryogenic regenerator for a Stirling cycle is designed using a fractional loss or entropy gain as the criterion of performance. The gas losses are treated separately from heat storage medium losses. For the optimum channel flow nonturbulent design, the maximization of heat transfer from the gas to the wall and the minimization of entropy production by friction leads to a gas flow velocity criterion of sound speed times loss fraction. This velocity with a given frequency leads to a Stirling cycle dead volume ratio and consequently a channel of specified length and width. The thermal properties of the channel wall must then accommodate this cyclic heat flow without substantially increasing the loss fraction. It is found that stainless steel or plastics are adequate for 30 to 300 K, but that lower temperature stages 4 to 30 K require either a special lead alloy of moderate conductivity or a segmented anisotropic construction of alternate highly conducting lead layers and alternate insulating glass or epoxy fiber glass spacers. An overall efficiency of {congruent} 50% of Carnot is predicted at a frequency of 30 Hz and a pressure of one atmosphere.

  2. Maximum cycle work output optimization for generalized radiative law Otto cycle engines

    NASA Astrophysics Data System (ADS)

    Xia, Shaojun; Chen, Lingen; Sun, Fengrui

    2016-11-01

    An Otto cycle internal combustion engine which includes thermal and friction losses is investigated by finite-time thermodynamics, and the optimization objective is the maximum cycle work output. The thermal energy transfer from the working substance to the cylinder inner wall follows the generalized radiative law (q∝Δ (Tn)). Under the condition that all of the fuel consumption, the compression ratio and the cycle period are given, the optimal piston trajectories for both the examples with unlimited and limited accelerations on every stroke are determined, and the cycle-period distribution among all strokes is also optimized. Numerical calculation results for the case of radiative law are provided and compared with those obtained for the cases of Newtonian law and linear phenomenological law. The results indicate that the optimal piston trajectory on each stroke contains three sections, which consist of an original maximum-acceleration and a terminal maximum-deceleration parts; for the case of radiative law, optimizing the piston motion path can achieve an improvement of more than 20% in both the cycle-work output and the second-law efficiency of the Otto cycle compared with the conventional near-sinusoidal operation, and heat transfer mechanisms have both qualitative and quantitative influences on the optimal paths of piston movements.

  3. Advanced Nuclear Fuel Cycle Transitions: Optimization, Modeling Choices, and Disruptions

    NASA Astrophysics Data System (ADS)

    Carlsen, Robert W.

    Many nuclear fuel cycle simulators have evolved over time to help understan the nuclear industry/ecosystem at a macroscopic level. Cyclus is one of th first fuel cycle simulators to accommodate larger-scale analysis with it liberal open-source licensing and first-class Linux support. Cyclus also ha features that uniquely enable investigating the effects of modeling choices o fuel cycle simulators and scenarios. This work is divided into thre experiments focusing on optimization, effects of modeling choices, and fue cycle uncertainty. Effective optimization techniques are developed for automatically determinin desirable facility deployment schedules with Cyclus. A novel method fo mapping optimization variables to deployment schedules is developed. Thi allows relationships between reactor types and scenario constraints to b represented implicitly in the variable definitions enabling the usage o optimizers lacking constraint support. It also prevents wasting computationa resources evaluating infeasible deployment schedules. Deployed power capacit over time and deployment of non-reactor facilities are also included a optimization variables There are many fuel cycle simulators built with different combinations o modeling choices. Comparing results between them is often difficult. Cyclus flexibility allows comparing effects of many such modeling choices. Reacto refueling cycle synchronization and inter-facility competition among othe effects are compared in four cases each using combinations of fleet of individually modeled reactors with 1-month or 3-month time steps. There are noticeable differences in results for the different cases. The larges differences occur during periods of constrained reactor fuel availability This and similar work can help improve the quality of fuel cycle analysi generally There is significant uncertainty associated deploying new nuclear technologie such as time-frames for technology availability and the cost of buildin advanced reactors

  4. Optimizing product life cycle processes in design phase

    NASA Astrophysics Data System (ADS)

    Faneye, Ola. B.; Anderl, Reiner

    2002-02-01

    Life cycle concepts do not only serve as basis in assisting product developers understand the dependencies between products and their life cycles, they also help in identifying potential opportunities for improvement in products. Common traditional concepts focus mainly on energy and material flow across life phases, necessitating the availability of metrics derived from a reference product. Knowledge of life cycle processes won from an existing product is directly reused in its redesign. Depending on sales volume nevertheless, the environmental impact before product optimization can be substantial. With modern information technologies today, computer-aided life cycle methodologies can be applied well before product use. On the basis of a virtual prototype, life cycle processes are analyzed and optimized, using simulation techniques. This preventive approach does not only help in minimizing (or even eliminating) environmental burdens caused by product, costs incurred due to changes in real product can also be avoided. The paper highlights the relationship between product and life cycle and presents a computer-based methodology for optimizing the product life cycle during design, as presented by SFB 392: Design for Environment - Methods and Tools at Technical University, Darmstadt.

  5. Sequential deposition: optimization of solvent swelling for high-performance polymer solar cells.

    PubMed

    Liu, Yao; Liu, Feng; Wang, Hsin-Wei; Nordlund, Dennis; Sun, Zhiwei; Ferdous, Sunzida; Russell, Thomas P

    2015-01-14

    Organic solar cells based on a typical DPP polymer were systematically optimized by a solvent swelling assisted sequential deposition process. We investigated the influence of solvent swelling on the morphology and structure order of the swollen film and the resultant device performance. Morphological and structural characterization confirmed the realization of ideal bulk heterojunctions using a suitable swelling solvent. A trilayered morphology was also found with the conjugated polymer concentrated bottom layer, PC71BM concentrated top layer, and interpenetrated networks of donor and acceptor in the middle by solvent swelling instead of thermal annealing in the sequential solution processing method. We proposed a simple strategy to optimize the sequential deposition fabricated devices by tuning the concentration of the PC71BM solution instead of thermal annealing. The best device showed a PCE of 7.59% with a Voc of 0.61 V, Jsc of 17.95 mA/cm(2), and FF of 69.6%, which is the highest reported efficiency for devices fabricated by a sequential processing method and among the best results for DPP polymers.

  6. Optimizing conceptual aircraft designs for minimum life cycle cost

    NASA Technical Reports Server (NTRS)

    Johnson, Vicki S.

    1989-01-01

    A life cycle cost (LCC) module has been added to the FLight Optimization System (FLOPS), allowing the additional optimization variables of life cycle cost, direct operating cost, and acquisition cost. Extensive use of the methodology on short-, medium-, and medium-to-long range aircraft has demonstrated that the system works well. Results from the study show that optimization parameter has a definite effect on the aircraft, and that optimizing an aircraft for minimum LCC results in a different airplane than when optimizing for minimum take-off gross weight (TOGW), fuel burned, direct operation cost (DOC), or acquisition cost. Additionally, the economic assumptions can have a strong impact on the configurations optimized for minimum LCC or DOC. Also, results show that advanced technology can be worthwhile, even if it results in higher manufacturing and operating costs. Examining the number of engines a configuration should have demonstrated a real payoff of including life cycle cost in the conceptual design process: the minimum TOGW of fuel aircraft did not always have the lowest life cycle cost when considering the number of engines.

  7. Modeling and optimization of a hybrid solar combined cycle (HYCS)

    NASA Astrophysics Data System (ADS)

    Eter, Ahmad Adel

    2011-12-01

    The main objective of this thesis is to investigate the feasibility of integrating concentrated solar power (CSP) technology with the conventional combined cycle technology for electric generation in Saudi Arabia. The generated electricity can be used locally to meet the annual increasing demand. Specifically, it can be utilized to meet the demand during the hours 10 am-3 pm and prevent blackout hours, of some industrial sectors. The proposed CSP design gives flexibility in the operation system. Since, it works as a conventional combined cycle during night time and it switches to work as a hybrid solar combined cycle during day time. The first objective of the thesis is to develop a thermo-economical mathematical model that can simulate the performance of a hybrid solar-fossil fuel combined cycle. The second objective is to develop a computer simulation code that can solve the thermo-economical mathematical model using available software such as E.E.S. The developed simulation code is used to analyze the thermo-economic performance of different configurations of integrating the CSP with the conventional fossil fuel combined cycle to achieve the optimal integration configuration. This optimal integration configuration has been investigated further to achieve the optimal design of the solar field that gives the optimal solar share. Thermo-economical performance metrics which are available in the literature have been used in the present work to assess the thermo-economic performance of the investigated configurations. The economical and environmental impact of integration CSP with the conventional fossil fuel combined cycle are estimated and discussed. Finally, the optimal integration configuration is found to be solarization steam side in conventional combined cycle with solar multiple 0.38 which needs 29 hectare and LEC of HYCS is 63.17 $/MWh under Dhahran weather conditions.

  8. Optimization of solid lipid nanoparticles prepared by a single emulsification-solvent evaporation method.

    PubMed

    Pooja, Deep; Tunki, Lakshmi; Kulhari, Hitesh; Reddy, Bharathi B; Sistla, Ramakrishna

    2016-03-01

    This data article contains the data related to the research article "Characterization, biorecognitive activity and stability of WGA grafted lipid nanostructures for the controlled delivery of rifampicin" (Pooja et al. 2015) [1]. In the present study, SLN were prepared by a single emulsification-solvent evaporation method and the various steps of SLN preparation are shown in a flow chart. The preparation of SLN was optimized for various formulation variables including type and quantity of lipid, surfactant, amount of co-surfactant and volume of organic phase. Similarly, effect of variables related to homogezation, sonication and stirring processes, on the size and surface potential of SLN was determined and optimized.

  9. Optimization of solvent extraction of shea butter (Vitellaria paradoxa) using response surface methodology and its characterization.

    PubMed

    Ajala, E O; Aberuagba, F; Olaniyan, A M; Onifade, K R

    2016-01-01

    Shea butter (SB) was extracted from its kernel by using n-hexane as solvent in an optimization study. This was to determine the optima operating variables that would give optimum yield of SB and to study the effect of solvent on the physico-chemical properties and chemical composition of SB extracted using n-hexane. A Box-behnken response surface methodology (RSM) was used for the optimization study while statistical analysis using ANOVA was used to test the significance of the variables for the process. The variables considered for this study were: sample weight (g), solvent volume (ml) and extraction time (min). The physico-chemical properties of SB extracted were determined using standard methods and Fourier Transform Infrared Spectroscopy (FTIR) for the chemical composition. The results of RSM analysis showed that the three variables investigated have significant effect (p < 0.05) on the %yield of SB, with R(2) - 0.8989 which showed good fitness of a second-order model. Based on this model, optima operating variables for the extraction process were established as: sample weight of 30.04 g, solvent volume of 346.04 ml and extraction time of 40 min, which gave 66.90 % yield of SB. Furthermore, the result of the physico-chemical properties obtained for the shea butter extracted using traditional method (SBT) showed that it is a more suitable raw material for food, biodiesel production, cosmetics, medicinal and pharmaceutical purposes than shea butter extracted using solvent extraction method (SBS). Fourier Transform Infrared Spectroscopy (FTIR) results obtained for the two samples were similar to what was obtainable from other vegetable oil.

  10. Cycling Transcriptional Networks Optimize Energy Utilization on a Genome Scale.

    PubMed

    Wang, Guang-Zhong; Hickey, Stephanie L; Shi, Lei; Huang, Hung-Chung; Nakashe, Prachi; Koike, Nobuya; Tu, Benjamin P; Takahashi, Joseph S; Konopka, Genevieve

    2015-12-01

    Genes expressing circadian RNA rhythms are enriched for metabolic pathways, but the adaptive significance of cyclic gene expression remains unclear. We estimated the genome-wide synthetic and degradative cost of transcription and translation in three organisms and found that the cost of cycling genes is strikingly higher compared to non-cycling genes. Cycling genes are expressed at high levels and constitute the most costly proteins to synthesize in the genome. We demonstrate that metabolic cycling is accelerated in yeast grown under higher nutrient flux and the number of cycling genes increases ∼40%, which are achieved by increasing the amplitude and not the mean level of gene expression. These results suggest that rhythmic gene expression optimizes the metabolic cost of global gene expression and that highly expressed genes have been selected to be downregulated in a cyclic manner for energy conservation.

  11. Optimization of deep eutectic solvent-based ultrasound-assisted extraction of polysaccharides from Dioscorea opposita Thunb.

    PubMed

    Zhang, Lijin; Wang, Maoshan

    2017-02-01

    In this study, deep eutectic solvents were proposed for the ultrasound-assisted extraction of polysaccharides from Dioscorea opposita Thunb. Several deep eutectic solvents were prepared for the extraction of polysaccharides, among which the deep eutectic solvent composed of choline chloride and 1,4-butanediol was proved to be suitable for the extraction. Based on the screening of single-factor experiment design and orthogonal experiment design, three experimental factors were optimized for the Box-Behnken experimental design combined with response surface methodology, which gave the optimal extraction conditions: water content of 32.89%(v/v), extraction temperature of 94.00°C, and the extraction time of 44.74min. The optimal extraction conditions could supply higher extraction yield than those of hot water extraction and water-based ultrasound-assisted extraction. Therefore, deep eutectic solvents were an excellent extraction solvent alternative to the extraction of polysaccharides from sample matrices.

  12. Composition optimization and stability testing of a parenteral antifungal solution based on a ternary solvent system.

    PubMed

    Kovács, Kristóf; Antal, István; Stampf, György; Klebovich, Imre; Ludányi, Krisztina

    2010-03-01

    An intravenous solution is a dosage forms intended for administration into the bloodstream. This route is the most rapid and the most bioavailable method of getting drugs into systemic circulation, and therefore it is also the most liable to cause adverse effects. In order to reduce the possibility of side effects and to ensure adequate clinical dosage of the formulation, the primarily formulated composition should be optimized. It is also important that the composition should retain its therapeutic effectiveness and safety throughout the shelf-life of the product. This paper focuses on the optimization and stability testing of a parenteral solution containing miconazole and ketoconazole solubilized with a ternary solvent system as model drugs. Optimization of the solvent system was performed based on assessing the risk/benefit ratio of the composition and its properties upon dilution. Stability tests were conducted based on the EMEA (European Medicines Agency) "guideline on stability testing: stability testing of existing active substances and related finished products". Experiments show that both the amount of co-solvent and surface active agent of the solvent system could substantially be reduced, while still maintaining adequate solubilizing power. It is also shown that the choice of various containers affects the stability of the compositions. It was concluded that by assessing the risk/benefit ratio of solubilizing power versus toxicity, the concentration of excipients could be considerably decreased while still showing a powerful solubilizing effect. It was also shown that a pharmaceutically acceptable shelf-life could be assigned to the composition, indicating good long-term stability.

  13. Wood energy fuel cycle optimization in beech and spruce forests

    NASA Astrophysics Data System (ADS)

    Meyer, Nickolas K.; Mina, Marco

    2012-03-01

    A novel synergistic approach to reducing emissions from residential wood combustion (RWC) is presented. Wood energy fuel cycle optimization (FCO) aims to provide cleaner burning fuels through optimization of forestry and renewable energy management practices. In this work, beech and spruce forests of average and high quality were modelled and analysed to determine the volume of fuel wood and its associated bark fraction produced during typical forestry cycles. Two separate fuel wood bark production regimes were observed for beech trees, while only one production regime was observed for spruce. The single tree and stand models were combined with existing thinning parameters to replicate existing management practices. Utilizing estimates of initial seedling numbers and existing thinning patterns a dynamic model was formed that responded to changes in thinning practices. By varying the thinning parameters, this model enabled optimization of the forestry practices for the reduction of bark impurities in the fuel wood supply chain. Beech forestry cycles responded well to fuel cycle optimization with volume reductions of bark from fuel wood of between ˜10% and ˜20% for average and high quality forest stands. Spruce, on the other hand, was fairly insensitive to FCO with bark reductions of 0-5%. The responsiveness of beech to FCO further supports its status as the preferred RWC fuel in Switzerland. FCO could easily be extended beyond Switzerland and applied across continental Europe and North America.

  14. Optimization by response surface methodology of lutein recovery from paprika leaves using accelerated solvent extraction.

    PubMed

    Kang, Jae-Hyun; Kim, Suna; Moon, BoKyung

    2016-08-15

    In this study, we used response surface methodology (RSM) to optimize the extraction conditions for recovering lutein from paprika leaves using accelerated solvent extraction (ASE). The lutein content was quantitatively analyzed using a UPLC equipped with a BEH C18 column. A central composite design (CCD) was employed for experimental design to obtain the optimized combination of extraction temperature (°C), static time (min), and solvent (EtOH, %). The experimental data obtained from a twenty sample set were fitted to a second-order polynomial equation using multiple regression analysis. The adjusted coefficient of determination (R(2)) for the lutein extraction model was 0.9518, and the probability value (p=0.0000) demonstrated a high significance for the regression model. The optimum extraction conditions for lutein were temperature: 93.26°C, static time: 5 min, and solvent: 79.63% EtOH. Under these conditions, the predicted extraction yield of lutein was 232.60 μg/g.

  15. Optimized Li-Ion Electrolytes Containing Fluorinated Ester Co-Solvents

    NASA Technical Reports Server (NTRS)

    Prakash, G. K. Surya; Smart, Marshall; Smith, Kiah; Bugga, Ratnakumar

    2010-01-01

    A number of experimental lithium-ion cells, consisting of MCMB (meso-carbon microbeads) carbon anodes and LiNi(0.8)Co(0.2)O2 cathodes, have been fabricated with increased safety and expanded capability. These cells serve to verify and demonstrate the reversibility, low-temperature performance, and electrochemical aspects of each electrode as determined from a number of electrochemical characterization techniques. A number of Li-ion electrolytes possessing fluorinated ester co-solvents, namely trifluoroethyl butyrate (TFEB) and trifluoroethyl propionate (TFEP), were demonstrated to deliver good performance over a wide temperature range in experimental lithium-ion cells. The general approach taken in the development of these electrolyte formulations is to optimize the type and composition of the co-solvents in ternary and quaternary solutions, focusing upon adequate stability [i.e., EC (ethylene carbonate) content needed for anode passivation, and EMC (ethyl methyl carbonate) content needed for lowering the viscosity and widening the temperature range, while still providing good stability], enhancing the inherent safety characteristics (incorporation of fluorinated esters), and widening the temperature range of operation (the use of both fluorinated and non-fluorinated esters). Further - more, the use of electrolyte additives, such as VC (vinylene carbonate) [solid electrolyte interface (SEI) promoter] and DMAc (thermal stabilizing additive), provide enhanced high-temperature life characteristics. Multi-component electrolyte formulations enhance performance over a temperature range of -60 to +60 C. With the need for more safety with the use of these batteries, flammability was a consideration. One of the solvents investigated, TFEB, had the best performance with improved low-temperature capability and high-temperature resilience. This work optimized the use of TFEB as a co-solvent by developing the multi-component electrolytes, which also contain non

  16. Optimal mixing rate in linear solvent strength gradient liquid chromatography. Balanced mixing program.

    PubMed

    Blumberg, Leonid M; Desmet, Gert

    2016-12-09

    The mixing rate (Rϕ) is the temporal rate of increase in the solvent strength in gradient LC. The optimal Rϕ (Rϕ,Opt) is the one at which a required peak capacity of gradient LC analysis is obtained in the shortest time. The balanced mixing program is a one where, for better separation of early eluting solutes, the mixing ramp is preceded by a balanced isocratic hold of the duration depending on Rϕ. The improvement in the separation of the earlier eluites due to the balanced programming has been evaluated. The value of Rϕ,Opt depends on the solvent composition range covered by the mixing ramp and on the column pressure conditions. The Rϕ,Opt for a column operating at maximum instrumental pressure is different from Rϕ,Opt for a column operating below the instrumental pressure limit. On the other hand, it has been shown that the difference in the Rϕ,Opt values under different conditions is not very large so that a single default Rϕ previously recommended for gradient analyses without the isocratic hold also yields a good approximation to the shortest analysis time for all conditions in the balanced analyses. With or without the initial balance isocratic hold, the recommended default Rϕ is about 5%/t0 (5% increase in the solvent strength per each t0-long increment in time) for small-molecule samples, and about an order of magnitude slower (0.5%/t0) for protein samples. A discussion illustrating the use of the optimization criteria employed here for the techniques other than LSS gradient LC is included.

  17. A technique for integrating engine cycle and aircraft configuration optimization

    NASA Technical Reports Server (NTRS)

    Geiselhart, Karl A.

    1994-01-01

    A method for conceptual aircraft design that incorporates the optimization of major engine design variables for a variety of cycle types was developed. The methodology should improve the lengthy screening process currently involved in selecting an appropriate engine cycle for a given application or mission. The new capability will allow environmental concerns such as airport noise and emissions to be addressed early in the design process. The ability to rapidly perform optimization and parametric variations using both engine cycle and aircraft design variables, and to see the impact on the aircraft, should provide insight and guidance for more detailed studies. A brief description of the aircraft performance and mission analysis program and the engine cycle analysis program that were used is given. A new method of predicting propulsion system weight and dimensions using thermodynamic cycle data, preliminary design, and semi-empirical techniques is introduced. Propulsion system performance and weights data generated by the program are compared with industry data and data generated using well established codes. The ability of the optimization techniques to locate an optimum is demonstrated and some of the problems that had to be solved to accomplish this are illustrated. Results from the application of the program to the analysis of three supersonic transport concepts installed with mixed flow turbofans are presented. The results from the application to a Mach 2.4, 5000 n.mi. transport indicate that the optimum bypass ratio is near 0.45 with less than 1 percent variation in minimum gross weight for bypass ratios ranging from 0.3 to 0.6. In the final application of the program, a low sonic boom fix a takeoff gross weight concept that would fly at Mach 2.0 overwater and at Mach 1.6 overland is compared with a baseline concept of the same takeoff gross weight that would fly Mach 2.4 overwater and subsonically overland. The results indicate that for the design mission

  18. Optimization of buffer injection for the effective bioremediation of chlorinated solvents in aquifers

    NASA Astrophysics Data System (ADS)

    Brovelli, A.; Robinson, C.; Barry, A.; Kouznetsova, I.; Gerhard, J.

    2008-12-01

    Various techniques have been proposed to enhance biologically-mediated reductive dechlorination of chlorinated solvents in the subsurface, including the addition of fermentable organic substrate for the generation of H2 as an electron donor. One rate-limiting factor for enhanced dechlorination is the pore fluid pH. Organic acids and H+ ions accumulate in dechlorination zones, generating unfavorable conditions for microbial activity (pH < 6.5). The pH variation is a nonlinear function of the amount of reduced chlorinated solvents, and is affected by the organic material fermented, the chemical composition of the pore fluid and the soil's buffering capacity. Consequently, in some cases enhanced remediation schemes rely on buffer injection (e.g., bicarbonate) to alleviate this problem, particularly in the presence of solvent nonaqueous phase liquid (NAPL) source zones. However, the amount of buffer required - particularly in complex, evolving biogeochemical environments - is not well understood. To investigate this question, this work builds upon a geochemical numerical model (Robinson et al., Science of the Total Environment, submitted), which computes the amount of additional buffer required to maintain the pH at a level suitable for bacterial activity for batch systems. The batch model was coupled to a groundwater flow/solute transport/chemical reaction simulator to permit buffer optimization computations within the context of flowing systems exhibiting heterogeneous hydraulic, physical and chemical properties. A suite of simulations was conducted in which buffer optimization was examined within the bounds of the minimum concentration necessary to sustain a pH favorable to microbial activity and the maximum concentration to avoid excessively high pH values (also not suitable to bacterial activity) and mineral precipitation (e.g., calcite, which may lead to pore-clogging). These simulations include an examination of the sensitivity of this buffer concentration range

  19. Optimization of nanolime solvent for the consolidation of coarse porous limestone

    NASA Astrophysics Data System (ADS)

    Borsoi, Giovanni; Lubelli, Barbara; van Hees, Rob; Veiga, Rosário; Silva, António Santos

    2016-09-01

    The potentialities of nanomaterials for application in the field of conservation have been widely investigated in the last two decades. Among nanomaterials, nanolimes, i.e., dispersions of lime nanoparticles in alcohols are promising consolidating products for calcareous materials. Nanolimes are effective in recovering the very superficial loss of cohesion of decayed materials, but they do not always provide sufficient mass consolidation. This limitation is mainly related to the deposition of the nanoparticles nearby the surface of the material. Experimental research has been set up with the aim of improving the in-depth deposition of lime nanoparticles. Previous research by the authors has shown that nanolime deposition within a substrate can be controlled by adapting the nanolimes properties (kinetic stability and evaporation rate) to the moisture transport behavior of the substrate. Nanolime properties can be modified by the use of different solvents. In this research, nanolime dispersions have been further optimized for application on Maastricht limestone, a coarse porous limestone. Firstly, nanolimes were synthesized and dispersed in ethanol and/or water, both pure and mixed in different percentages. Subsequently, based on the kinetic stability of the nanolime dispersions, the most promising solvent mixtures were selected and applied on the limestone. The deposition of lime nanoparticles within the limestone was studied by phenolphthalein test, optical microscopy and scanning electron microscopy. The results confirm that nanolime dispersed in a mixture of ethanol (95 %) and water (5 %) can guarantee a better nanoparticles in-depth deposition within coarse porous substrates, when compared to dispersions in pure ethanol.

  20. Extraction optimization of Loratadine by supramolecular solvent-based microextraction and its determination using HPLC.

    PubMed

    Peyrovi, Moazameh; Hadjmohammadi, Mohammadreza

    2015-02-01

    Optimization of supramolecular solvent-based microextraction (SSME) of Loratadine and its determination with high-performance liquid chromatography (HPLC) with ultra violet (UV) detection were investigated. A factorial design (FD) and a central composite face-centered (CCF) were applied to evaluate the SSME procedure. The effect of four parameters on extraction efficiency was investigated. The factors studied were decanoic acid amount, percentage of tetrahydrofuran (THF) (v/v), pH and extraction time. According to half factorial design results, the effective parameters were decanoic acid amount, THF percentage (v/v) and pH. Then, a CCF was applied to obtain optimal condition. The optimized conditions were obtained at 110mg of decanoic acid, 10% of THF and pH=3. The limits of detection were in the range of 0.3-0.4ng/ml. Linearity of the method was determined to be in the range of 1.0-400.0ng/ml for distilled water and 1.3-400.0ng/ml for plasma. The extraction recovery was >92%. RSD for intra and inter day (n=5) of extraction of Loratadine were 3.1% and 6.2%, respectively. The developed method was successfully applied for the determination of Loratadine in distilled water and plasma samples.

  1. Optimization of conjugated linoleic acid triglycerides via enzymatic esterification in no-solvent system

    NASA Astrophysics Data System (ADS)

    Yi, Dan; Sun, Xiuqin; Li, Guangyou; Liu, Fayi; Lin, Xuezheng; Shen, Jihong

    2009-09-01

    We compared four esterifiable enzymes. The lipase Novozym 435 possessed the highest activity for the conjugated linoleic acid esterification during the synthesis of triglycerides. The triglycerides were synthesized by esterification of glycerol and conjugated linoleic acid (CLA) in a no-solvent system using lipase catalysis. We investigated the effects of temperature, enzyme concentration, water content, and time on esterification. Enzyme and water concentrations of up to 1% of the total reaction volume and a system temperature of 60°C proved optimal for esterification. Similarly, when the esterification was carried out for 24 h, the reaction ratio improved to 94.11%. The esterification rate of the rotating screen basket remained high (87.28%) when the enzyme was re-used for the 5th time. We evaluated the substrate selectivity of lipase (NOVO 435) and determined that this lipase prefers the 10,12-octadacadienoic acid to the 9,11-octadecadienoic acid.

  2. A simple method to optimize the HSCCC two-phase solvent system by predicting the partition coefficient for target compound.

    PubMed

    Han, Quan-Bin; Wong, Lina; Yang, Nian-Yun; Song, Jing-Zheng; Qiao, Chun-Feng; Yiu, Hillary; Ito, Yoichiro; Xu, Hong-Xi

    2008-04-01

    A simple method was developed to optimize the solvent ratio of the two-phase solvent system used in the high-speed counter-current chromatography (HSCCC) separation. Some mathematic equations, such as the exponential and the power equations, were established to describe the relationship between the solvent ratio and the partition coefficient. Using this new method, the two-phase solvent system was easily optimized to obtain a proper partition coefficient for the CCC separation of the target compound. Furthermore, this method was satisfactorily applied in determining the two-phase solvent system for the HSCCC preparation of pseudolaric acid B from the Chinese herb Pseudolarix kaempferi Gordon (Pinaceae). The two-phase solvent system of n-hexane/EtOAc/MeOH/H(2)O (5:5:5:5 by volume) was used with a good partition coefficient K = 1.08. As a result, 232.05 mg of pseudolaric acid B was yielded from 0.5 g of the crude extract with a purity of 97.26% by HPLC analysis.

  3. Optimal life-cycle profiles of fertility and labor supply.

    PubMed

    Moffitt, R

    1984-01-01

    A model of life cycle fertility is developed using the language and framework of optimal control theory. The chief characteristic of children that distinguishes them from other consumer durables is, in the language of the optimal growth theory, the "irreversibility of investment." As the good does not depreciate in the ordinary sense, the stock must be monotonically nondecreasing over time. The optimal profile of fertility is, for this reason, characterized by the same type of "bang-bang" behavior found in many optimal growth problems. Yet, the fertility decision is complicated considerably by several other factors. Chief among these is the intrinsic relation to the labor-supply decision, for having children implies inevitable constraints on the mother's or father's time. Thus, optimal labor-supply decisions also must be considered. The model is developed in stages, proceeding from very simple to the more complex models. 1 section introduces the impact of fertility on the future demands for home time. It is shown that optimal fertility profiles follow turnpike paths similar to those in the growth-theory literature. A subsequent section introduces labor-supply and human-captial considerations. As the models become more complex, solutions become harder to derive and are often only outlined. The analysis provides some theoretical basis for expecting certain shapes of the life-cycle profiles of fertility, labor supply, and wages. Fertility profiles may be of 2 shapes--one beginning at a high rate, falling to a lower rate, then to zero; and one beginning at zero, rising to a moderate rate, then falling back down to zero. Labor supply profiles can be of a number of different shapes, but the impact of childbearing is to lower hours worked during the early childrearing period. As the children mature, hours worked rise (or at least fall more slowly) as home time responsibilities lessen, although the level to which they rise will probably be lower than before the 1st birth

  4. Optimal extraction and fingerprinting of carotenoids by accelerated solvent extraction and liquid chromatography with tandem mass spectrometry.

    PubMed

    Saha, Supradip; Walia, Suresh; Kundu, Aditi; Sharma, Khushbu; Paul, Ranjit Kumar

    2015-06-15

    Accelerated solvent extraction (ASE) is applied for the extraction of carotenoids from orange carrot and the extraction parameters were optimized. Two carotenoids, lutein and β-carotene, are selected as the validation process. Hildebrand solubility parameters and dielectric constant of solvents were taken into consideration in selecting solvent mixture. The effects of various experimental parameters, such as temperature, static time, drying agent etc., on the ASE extraction efficiency are investigated systematically. Interactions among the variables were also studied. Furthermore, two carotenoids were analyzed and characterized by LC-ESI MS. The study concluded that Hildebrand solubility parameter approach may be applicable for less polar bioactive molecules like carotenoids. The properties of solvent and extraction temperature are found to be the most important parameters affecting the ASE extraction efficiency of thermolabile natural compounds.

  5. Solvent optimization for anthocyanin extraction from Syzygium cumini L. Skeels using response surface methodology.

    PubMed

    Chaudhary, Bratati; Mukhopadhyay, Kunal

    2013-05-01

    Anthocyanins are plant pigments that are potential candidates for use as natural food colourant. In this study, Syzygium cumini fruit skin has been used as anthocyanin source. All the six major types of anthocyanins were identified in the sample by ultra performance liquid chromatography studies, and the antioxidant activity was found to be 4.34 ± 0.26 Fe(2+)g(- 1) in the sample with highest anthocyanin content. Optimization of conditions for extracting high amounts of anthocyanin from the fruit peels was investigated by response surface methodology. The results suggested that highest anthocyanin yield (763.80 mg; 100 ml(- 1)), highest chroma and hue angle in the red colour range could be obtained when 20% ethanol was used in combination with 1% acetic acid. Methanol was replaced with ethanol for the extraction of pigments due to its less toxicity and being safe for human consumption. The optimized solvent can be used to extract anthocyanins from the S. cumini fruits and used as natural colourants in the food industries.

  6. Deep Eutectic Solvents Modified Molecular Imprinted Polymers for Optimized Purification of Chlorogenic Acid from Honeysuckle.

    PubMed

    Li, Guizhen; Wang, Wei; Wang, Qian; Zhu, Tao

    2016-02-01

    Deep eutectic solvents (DES) were synthesized with choline chloride (ChCl), and DES modified molecular imprinted polymers (DES-MIPs), DES modified non-imprinted polymers (DES-NIPs, without template), MIPs and NIPs were prepared in an identical procedure. Fourier transform infrared spectrometer (FT-IR) and field emission scanning electron microscopy (FE-SEM) were used to characterize the obtained polymers. Rebinding experiment and solid-phase extraction (SPE) were used to prove the high selectivity adsorption properties of the polymers. Box-Behnken design (BBD) with three factors was used to optimize the extraction condition of chlorogenic acid (CA) from honeysuckles. The optimum extraction conditions were found to be ultrasonic time optimized (20 min), the volume fraction of ethanol (60%) and ratio of liquid to material (15 mL g(-1)). Under these conditions, the mean extraction yield of CA was 12.57 mg g(-1), which was in good agreement with the predicted BBD model value. Purification of hawthorn extract was achieved by SPE process, and SPE recoveries of CA were 72.56, 64.79, 69.34 and 60.08% by DES-MIPs, DES-NIPs, MIPs and NIPs, respectively. The results showed DES-MIPs had potential for promising functional adsorption material for the purification of bioactive compounds.

  7. Optimization in solvent selection for chlorin e6 in photodynamic therapy.

    PubMed

    Paul, Shubhajit; Heng, Paul Wan Sia; Chan, Lai Wah

    2013-03-01

    The photophysical properties of chlorin e6 (Ce6) in twelve different protic, aprotic and non-polar solvents were investigated using ultraviolet-visible and fluorescence spectroscopic methods. Solvatochromic effects were determined by the changes in quantum yield, Stokes shift, fluorescence half-life and excited state dipole moments of Ce6 in the different solvents. The absorption shifts observed in different solvents were further analyzed using the Kamlet-Abboud-Taft model and the nature of solute-solvent interactions between Ce6 and different protic and aprotic solvents was elucidated. The quantum yields were found highest in protic solvents (except water), followed by aprotic and non-polar solvents. Solvent polarity parameters showed a linear increasing trend with Stokes shift and fluorescence half-life, which indicated the presence of Ce6-solvent interaction. Using the Kamlet-Abboud-Taft model, a direct correlation between the solvent polarity parameters and absorption shift was observed, which substantiated the existence of Ce6-solvent interaction by hydrogen bond formation. The excited state dipole moments in specific protic and aprotic solvents were found to be higher than the ground state dipole moments, implying a more polar nature of Ce6 during excited state transition.

  8. Optimal digital control of a Stirling cycle cooler

    NASA Technical Reports Server (NTRS)

    Feeley, J.; Feeley, P.; Langford, G.

    1990-01-01

    This short paper describes work in progress on the conceptual design of a control system for a cryogenic cooler intended for use aboard spacecraft. The cooler will produce 5 watts of cooling at 65 K and will be used to support experiments associated with the following: earth observation; atmospheric measurements; infrared, x-ray, and gamma-ray astronomy; and magnetic field characterization. The cooler has been designed and constructed for NASA/GSFC by Philips Laboratories and is described in detail. The cooler has a number of unique design features intended to enhance long life and maintenance free operation in space including use of the high efficiency Stirling thermodynamic refrigeration cycle, linear magnetic motors, clearance-seals, and magnetic bearings. The proposed control system design is based on optimal control theory and is targeted for custom integrated circuit implementation. The resulting control system will meet the following mission requirements: efficiency, reliability, optimal thermodynamic, electrical, and mechanical performance; freedom from operator intervention; light weight; and small size.

  9. Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives.

    PubMed

    Schulz, Gisela L; Urdanpilleta, Marta; Fitzner, Roland; Brier, Eduard; Mena-Osteritz, Elena; Reinold, Egon; Bäuerle, Peter

    2013-01-01

    The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu 4 as donor in conjunction with PC61BM as acceptor is described. Power conversion efficiencies up to 3.0% and external quantum efficiencies up to 40% were obtained through the use of 1-chloronaphthalene as solvent additive in the fabrication of the photovoltaic devices. Furthermore, atomic force microscopy investigations of the photoactive layer gave insight into the distribution of donor and acceptor within the blend. The unique combination of solubility and thermal stability of DCV5T-Bu 4 also allows for fabrication of organic solar cells by vacuum deposition. Thus, we were able to perform a rare comparison of the device characteristics of the solution-processed DCV5T-Bu 4 :PC61BM solar cell with its vacuum-processed DCV5T-Bu 4 :C60 counterpart. Interestingly in this case, the efficiencies of the small-molecule organic solar cells prepared by using solution techniques are approaching those fabricated by using vacuum technology. This result is significant as vacuum-processed devices typically display much better performances in photovoltaic cells.

  10. Toxicological risk at workplace and toxicity as Life Cycle Assessment impact category: Substitution of solvents as an example.

    PubMed

    Schupp, Thomas; Georg, Philipp Alexander; Kirstein, Guenter

    2017-01-01

    Substitution of hazardous substances against less hazardous ones is a central requirement of the European Chemical Regulation REACH (European Regulation 1907/2006/EC). Hazardous substances emitted from products may not only affect the worker; drift off and distribution in the environment may finally result in exposure of the general population. This potential threat to health is covered by the impact category "toxicity" in Life Cycle Assessments. In this paper, we present a case of a substitution of volatile organic compounds in a reactive varnish, and compare the "old" formulation with the "new" formulation against health risk to the worker, and concerning the Life Cycle Assessment impact category "toxicity". The "old" formulation contained Naphtha (petroleum), hydrodesulfurized, heavy and Solvent naphtha (petroleum), light, aromatic. In the new formulation, both naphthas were replaced by n-Butylacetate, 1-Ethoxy-2-propyl acetate and Ethyl-3-ethoxy propionate. In the European Union, the naphthas are classified as mutagens and carcinogens category 1, officially. However, if benzene is below 0.1 %, registrants in the EU proposed to omit this classification, and todays naptha products on the market obviously have benzene contents below 0.1 %. On a first glance, the improvement for workplace safety introduced by the substitution, therefore, is comparatively small, as it is for toxicity in Life Cycle Assessment. However, when background knowledge concerning chemical production processes of naphtha is included, benzene below a content of 0.1 % needs to be taken into consideration, and the benefit of substitution is more obvious.

  11. Increasing the sampling efficiency of protein conformational transition using velocity-scaling optimized hybrid explicit/implicit solvent REMD simulation

    SciTech Connect

    Yu, Yuqi; Wang, Jinan; Shao, Qiang E-mail: Jiye.Shi@ucb.com Zhu, Weiliang E-mail: Jiye.Shi@ucb.com; Shi, Jiye E-mail: Jiye.Shi@ucb.com

    2015-03-28

    The application of temperature replica exchange molecular dynamics (REMD) simulation on protein motion is limited by its huge requirement of computational resource, particularly when explicit solvent model is implemented. In the previous study, we developed a velocity-scaling optimized hybrid explicit/implicit solvent REMD method with the hope to reduce the temperature (replica) number on the premise of maintaining high sampling efficiency. In this study, we utilized this method to characterize and energetically identify the conformational transition pathway of a protein model, the N-terminal domain of calmodulin. In comparison to the standard explicit solvent REMD simulation, the hybrid REMD is much less computationally expensive but, meanwhile, gives accurate evaluation of the structural and thermodynamic properties of the conformational transition which are in well agreement with the standard REMD simulation. Therefore, the hybrid REMD could highly increase the computational efficiency and thus expand the application of REMD simulation to larger-size protein systems.

  12. Toxicological risk at workplace and toxicity as Life Cycle Assessment impact category: Substitution of solvents as an example

    PubMed Central

    Schupp, Thomas; Georg, Philipp Alexander; Kirstein, Guenter

    2017-01-01

    Substitution of hazardous substances against less hazardous ones is a central requirement of the European Chemical Regulation REACH (European Regulation 1907/2006/EC). Hazardous substances emitted from products may not only affect the worker; drift off and distribution in the environment may finally result in exposure of the general population. This potential threat to health is covered by the impact category “toxicity” in Life Cycle Assessments. In this paper, we present a case of a substitution of volatile organic compounds in a reactive varnish, and compare the “old” formulation with the “new” formulation against health risk to the worker, and concerning the Life Cycle Assessment impact category “toxicity”. The “old” formulation contained Naphtha (petroleum), hydrodesulfurized, heavy and Solvent naphtha (petroleum), light, aromatic. In the new formulation, both naphthas were replaced by n-Butylacetate, 1-Ethoxy-2-propyl acetate and Ethyl-3-ethoxy propionate. In the European Union, the naphthas are classified as mutagens and carcinogens category 1, officially. However, if benzene is below 0.1 %, registrants in the EU proposed to omit this classification, and todays naptha products on the market obviously have benzene contents below 0.1 %. On a first glance, the improvement for workplace safety introduced by the substitution, therefore, is comparatively small, as it is for toxicity in Life Cycle Assessment. However, when background knowledge concerning chemical production processes of naphtha is included, benzene below a content of 0.1 % needs to be taken into consideration, and the benefit of substitution is more obvious. PMID:28337118

  13. ORGANIC-HIGH IONIC STRENGTH AQUEOUS SOLVENT SYSTEMS FOR SPIRAL COUNTER-CURRENT CHROMATOGRAPHY: GRAPHIC OPTIMIZATION OF PARTITION COEFFICIENT.

    PubMed

    Zeng, Yun; Liu, Gang; Ma, Ying; Chen, Xiaoyuan; Ito, Yoichiro

    2013-01-10

    A new series of organic-high ionic strength aqueous two-phase solvents systems was designed for separation of highly polar compounds by spiral high-speed counter-current chromatography. A total of 21 solvent systems composed of 1-butanol-ethanol-saturated ammonium sulfate-water at various volume ratios are arranged according to an increasing order of polarity. Selection of the two-phase solvent system for a single compound or a multiple sample mixture can be achieved by two steps of partition coefficient measurements using a graphic method. The capability of the method is demonstrated by optimization of partition coefficient for seven highly polar samples including tartrazine (K=0.77), tryptophan (K=1.00), methyl green (K= 0.93), tyrosine (0.81), metanephrine (K=0.89), tyramine (K=0.98), and normetanephrine (K=0.96). Three sulfonic acid components in D&C Green No. 8 were successfully separated by HSCCC using the graphic selection of the two-phase solvent system.

  14. Optimization of acetonitrile co-solvent and copper stoichiometry for pseudo-ligandless click chemistry with nucleic acids.

    PubMed

    Paredes, Eduardo; Das, Subha R

    2012-08-15

    The copper(I) catalyzed azide-alkyne cycloaddition 'click' reaction yields a specific product under mild conditions and in some of the most chemically complex environments. This reaction has been used extensively to tag DNA, proteins, glycans and only recently RNA. Click reactions in aqueous buffer typically include a ligand for Cu(I), however we find that acetonitrile as a minor co-solvent can serve this role. Here we investigate the click labeling of RNA and DNA in aqueous buffer to determine the relationship between the stoichoimetry of Cu(I) and the acetonitrile co-solvent that affects nucleic acid stability. We find that very low concentrations of acetonitrile perform equally well and obviate the need for any additional Cu(I) stabilizing ligand. These pseudo-ligandless reaction conditions are optimal for nucleic acids click conjugations.

  15. Optimal Cooling Load and COP Relationship of a Four-Heat-Reservoir Endoreversible Absorption Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Chen, Lingen; Zheng, Tong; Sun, Fengrui; Wu, Chih

    2004-06-01

    On the basis of a four-heat-reservoir endoreversible absorption refrigeration cycle model, another linear heat transfer law [i.e., the heat-flux] is adopted, the fundamental optimal relation between the coefficient of performance (COP) and the cooling load, as well as the maximum cooling load and the corresponding COP of the cycle coupled to constant-temperature heat reservoirs are derived by using finite-time thermodynamics or thermodynamic optimization. The optimal distribution of the heat-transfer surface areas is also obtained. Moreover, the effects of the cycle parameters on the COP and the cooling load of the cycle are studied by detailed numerical examples. The results obtained herein are of importance to the optimal design and performance improvement of an absorption refrigeration cycle.

  16. Revenue cycle optimization in health care institutions. A conceptual framework for change management.

    PubMed

    Mugdh, Mrinal; Pilla, Satya

    2012-01-01

    Health care providers in the United States are constantly faced with the enormous challenge of optimizing their revenue cycle to improve their overall financial performance. These challenges keep evolving in both scope and complexity owing to a host of internal and external factors. Furthermore, given the lack of control that health care providers have over external factors, any attempt to successfully optimize the revenue cycle hinges on several critical improvements aimed at realigning the internal factors. This study provides an integrated change management model that aims to reengineer and realign the people-process-technology framework by using the principles of lean and Six Sigma for revenue cycle optimization.

  17. Decision & Management Tools for DNAPL Sites: Optimization of Chlorinated Solvent Source and Plume Remediation Considering Uncertainty

    DTIC Science & Technology

    2010-09-01

    Liang Ronald W. Falta Clemson University Charles J. Newell Shahla K. Farhat GSI Environmental Inc. P. Suresh C. Rao Nandita Basu Purdue...site architecture [Rao et al. 2001; Rao and Jawitz, 2003; Parker and Park, 2004; Zhu and Sykes , 2004; Falta et al., 2005a;Falta, 2008, Parker and...Attenuation of Fuels and Chlorinated Solvents in the Subsurface. New York: John Wiley and Sons Inc. Zhu, J., and J.F. Sykes , 2004. Simple screening

  18. Realistic Challenges to Optimize the Closed Nuclear Fuel Cycle

    SciTech Connect

    Shigeo Nomura; Hisao Ojima; Hirohisa Ishikawa

    2002-07-01

    The first generation nuclear fuel cycle system will be closed in Japan by 2010 with the successful combination of LWR-MOX, industrial operation of reprocessing and MOX fuel fabrication plants, interim storage of spent fuel, and plans for the location of final disposal of radioactive wastes. To tailor nuclear power as the globally sustainable and environmentally benign energy source for future society, however, an advanced fuel cycle option is needed that is well suited to the fast reactor. It should recycle fissile materials of plutonium and uranium whilst transmuting minor actinides and generating minimum waste. (authors)

  19. Optimal flash rate and duty cycle for flashing visual indicators.

    NASA Technical Reports Server (NTRS)

    Markowitz, J.

    1971-01-01

    This experiment examined the ability of observers to determine, as quickly as possible, whether a visual indicator was steadily on or flashing. Six flash rates (periods) were combined factorially with three duty cycles (on-off ratios) to define 18 ?types' of intermittent signals. Experimental sessions were divided into six runs of 100 trials, each run utilizing one of the six flash rates. On any given trial in a run, the probability of a steady signal occurring was 0.5 and the probability of a flashing signal occurring was 0.5. A different duty cycle was employed daily for each experimental session. In all, 400 trials were devoted to each of the flash rates at each duty cycle. Accuracy and latency of response were the dependent variables of interest. The results show that the observers view the light for an interval of time appropriate to the expected flash rate and duty cycle; whether they judge the light to be steady or intermittent depends upon whether the light is extinguished during the predetermined waiting period. Adoption of this temporal criterion delays responding in comparison to those tasks involving responses to light onset. The decision or response criteria held by the observers are also sensitive to the parameters of the flashing light: observers become increasingly willing to call a flashing light ?steady' as flash duration increases.

  20. 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).

  1. Optimal analysis on the performance of an irreversible harmonic quantum Brayton refrigeration cycle.

    PubMed

    Lin, Bihong; Chen, Jincan

    2003-11-01

    An irreversible model of a quantum refrigeration cycle working with many noninteracting harmonic oscillators is established. The refrigeration cycle consists of two adiabatic and two constant-frequency processes. The general performance characteristics of the cycle are investigated, based on the quantum master equation and the semigroup approach. The expressions for several important performance parameters such as the coefficient of performance, cooling rate, power input, and rate of entropy production are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of temperatures of the working substance and times spent on the two constant-frequency processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is compared with that of a classical Brayton refrigerator working with an ideal gas. The results obtained here show that in the high-temperature limit a harmonic quantum Brayton cycle may be equivalent to a classical Brayton cycle.

  2. Optimization of organic Rankine cycles for space station applications

    NASA Astrophysics Data System (ADS)

    Eubanks, Dana L.; Best, Frederick R.; Faget, Nanette

    The purpose of the current program is to investigate the tradeoffs between solar dynamic and nuclear powered systems for the space station. This research is based on a typical Rankine cycle using toluene as the working fluid. The first objective is to produce an adequate thermodynamic cycle model and calculate its efficiency. The next step is to implement a sizing algorithm that calculates the capacity of the various elements of the system, such as the radiator and regenerator, for a given electrical output. Then, the mass of each component must be calculated to give the overall total system mass. Likewise, the space for each component can be determined, giving an estimate of what volume must be available to place the system into orbit.

  3. Optimization of organic Rankine cycles for space station applications

    NASA Technical Reports Server (NTRS)

    Eubanks, Dana L.; Best, Frederick R.; Faget, Nanette

    1988-01-01

    The purpose of the current program is to investigate the tradeoffs between solar dynamic and nuclear powered systems for the space station. This research is based on a typical Rankine cycle using toluene as the working fluid. The first objective is to produce an adequate thermodynamic cycle model and calculate its efficiency. The next step is to implement a sizing algorithm that calculates the capacity of the various elements of the system, such as the radiator and regenerator, for a given electrical output. Then, the mass of each component must be calculated to give the overall total system mass. Likewise, the space for each component can be determined, giving an estimate of what volume must be available to place the system into orbit.

  4. Decision & Management Tools for DNAPL Sites: Optimization of Chlorinated Solvent Source and Plume Remediation Considering Uncertainty

    DTIC Science & Technology

    2011-08-01

    Rao et al., 2001; Rao and Jawitz, 2003; Parker and Park, 2004; Zhu and Sykes , 2004; Falta et al., 2005aFalta, 2008; Parker and Falta, 2008): Γ...Fuels and Chlorinated Solvents in the Subsurface. New York: John Wiley and Sons, Inc. Zhu, J., and J.F. Sykes . 2004. Simple screening models of NAPL...340C Clemson, SC 29634-0919 Phone: 864-656-0125 Fax: 864-656-1041 E-mail: faltar@clemson.edu Project Team Lead Charles , J. Newell GSI

  5. Orbit Transfer Vehicle Engine Study. Phase A, extension 1: Advanced expander cycle engine optimization

    NASA Technical Reports Server (NTRS)

    Mellish, J. A.

    1979-01-01

    The performance optimization of expander cycle engines at vacuum thrust levels of 10K, 15K, and 20K lb is discussed. The optimization is conducted for a maximum engine length with an extendible nozzle in the retracted position of 60 inches and an engine mixture ratio of 6.0:1. The thrust chamber geometry and cycle analyses are documented. In addition, the sensitivity of a recommended baseline expander cycle to component performance variations is determined and chilldown/start propellant consumptions are estimated.

  6. Oyster Creek cycle 10 nodal model parameter optimization study using PSMS

    SciTech Connect

    Dougher, J.D.

    1987-01-01

    The power shape monitoring system (PSMS) is an on-line core monitoring system that uses a three-dimensional nodal code (NODE-B) to perform nodal power calculations and compute thermal margins. The PSMS contains a parameter optimization function that improves the ability of NODE-B to accurately monitor core power distributions. This functions iterates on the model normalization parameters (albedos and mixing factors) to obtain the best agreement between predicted and measured traversing in-core probe (TIP) reading on a statepoint-by-statepoint basis. Following several statepoint optimization runs, an average set of optimized normalization parameters can be determined and can be implemented into the current or subsequent cycle core model for on-line core monitoring. A statistical analysis of 19 high-power steady-state state-points throughout Oyster Creek cycle 10 operation has shown a consistently poor virgin model performance. The normalization parameters used in the cycle 10 NODE-B model were based on a cycle 8 study, which evaluated only Exxon fuel types. The introduction of General Electric (GE) fuel into cycle 10 (172 assemblies) was a significant fuel/core design change that could have altered the optimum set of normalization parameters. Based on the need to evaluate a potential change in the model normalization parameters for cycle 11 and in an attempt to account for the poor cycle 10 model performance, a parameter optimization study was performed.

  7. Optimal cycling time trial position models: aerodynamics versus power output and metabolic energy.

    PubMed

    Fintelman, D M; Sterling, M; Hemida, H; Li, F-X

    2014-06-03

    The aerodynamic drag of a cyclist in time trial (TT) position is strongly influenced by the torso angle. While decreasing the torso angle reduces the drag, it limits the physiological functioning of the cyclist. Therefore the aims of this study were to predict the optimal TT cycling position as function of the cycling speed and to determine at which speed the aerodynamic power losses start to dominate. Two models were developed to determine the optimal torso angle: a 'Metabolic Energy Model' and a 'Power Output Model'. The Metabolic Energy Model minimised the required cycling energy expenditure, while the Power Output Model maximised the cyclists׳ power output. The input parameters were experimentally collected from 19 TT cyclists at different torso angle positions (0-24°). The results showed that for both models, the optimal torso angle depends strongly on the cycling speed, with decreasing torso angles at increasing speeds. The aerodynamic losses outweigh the power losses at cycling speeds above 46km/h. However, a fully horizontal torso is not optimal. For speeds below 30km/h, it is beneficial to ride in a more upright TT position. The two model outputs were not completely similar, due to the different model approaches. The Metabolic Energy Model could be applied for endurance events, while the Power Output Model is more suitable in sprinting or in variable conditions (wind, undulating course, etc.). It is suggested that despite some limitations, the models give valuable information about improving the cycling performance by optimising the TT cycling position.

  8. Optimization strategies for sustainable fuel cycle of the BR2 Reactor

    SciTech Connect

    Kalcheva, S.; Van Den Branden, G.; Koonen, E.

    2013-07-01

    The objective of the present study is to achieve a sustainable fuel cycle in a long term of reactor operation applying advanced in-core loading strategies. The optimization criteria concern mainly enhancement of nuclear safety by means of reactivity margins and minimization of the operational fuel cycle cost at a given (constant) power level and same or longer cycle length. An important goal is also to maintain the same or to improve the experimental performances. Current developments are focused on optimization of control rods localization; optimization of fresh and burnt fuel assemblies in-core distribution; optimization of azimuth and axial fuel burn up strategies, including fuel assembly rotating and flipping upside down. (authors)

  9. Optimization of automotive Rankine cycle waste heat recovery under various engine operating condition

    NASA Astrophysics Data System (ADS)

    Punov, Plamen; Milkov, Nikolay; Danel, Quentin; Perilhon, Christelle; Podevin, Pierre; Evtimov, Teodossi

    2017-02-01

    An optimization study of the Rankine cycle as a function of diesel engine operating mode is presented. The Rankine cycle here, is studied as a waste heat recovery system which uses the engine exhaust gases as heat source. The engine exhaust gases parameters (temperature, mass flow and composition) were defined by means of numerical simulation in advanced simulation software AVL Boost. Previously, the engine simulation model was validated and the Vibe function parameters were defined as a function of engine load. The Rankine cycle output power and efficiency was numerically estimated by means of a simulation code in Python(x,y). This code includes discretized heat exchanger model and simplified model of the pump and the expander based on their isentropic efficiency. The Rankine cycle simulation revealed the optimum value of working fluid mass flow and evaporation pressure according to the heat source. Thus, the optimal Rankine cycle performance was obtained over the engine operating map.

  10. Optimization of a closed-cycle OTEC system

    SciTech Connect

    Uehara, H. . Faculty of Science and Engineering); Ikegami, Y. )

    1990-11-01

    Optimization of an ocean thermal energy conversion (OTEC) system is carried out by the Powell method (the method of steepest descent). The parameters in the objective function consist of the velocities of cold sea water and warm sea water passing through the heat exchangers, the phase change temperature, and turbine configuration (specific speed, specific diameter, ratio of blade to diameter). Numerical results are shown for a 100 MW OTEC plant with plate-type heat exchangers using ammonia as working fluid, and are compared with calculation results for the case when the turbine efficiency is fixed.

  11. Dual-objective optimization of organic Rankine cycle (ORC) systems using genetic algorithm: a comparison between basic and recuperative cycles

    NASA Astrophysics Data System (ADS)

    Hayat, Nasir; Ameen, Muhammad Tahir; Tariq, Muhammad Kashif; Shah, Syed Nadeem Abbas; Naveed, Ahmad

    2017-03-01

    Exploitation of low potential waste thermal energy for useful net power output can be done by manipulating organic Rankine cycle systems. In the current article dual-objectives ({{η}}_{th} and SIC) optimization of ORC systems [basic organic Rankine cycle (BORC) and recuperative organic Rankine cycle (RORC)] has been done using non-dominated sorting genetic algorithm (II). Seven organic compounds (R-123, R-1234ze, R-152a, R-21, R-236ea, R-245ca and R-601) have been employed in basic cycle and four dry compounds (R-123, R-236ea, R-245ca and R-601) have been employed in recuperative cycle to investigate the behaviour of two systems and compare their performance. Sensitivity analyses show that recuperation boosts the thermodynamic behaviour of systems but it also raises specific investment cost significantly. R-21, R-245ca and R-601 show attractive performance in BORC whereas R-601 and R-236ea in RORC. RORC, due to higher total investment cost and operation & maintenance costs, has longer payback periods as compared to BORC.

  12. Optimization of HS-GC-FID-MS Method for Residual Solvent Profiling in Active Pharmaceutical Ingredients Using DoE.

    PubMed

    Poceva Panovska, Ana; Acevska, Jelena; Stefkov, Gjoshe; Brezovska, Katerina; Petkovska, Rumenka; Dimitrovska, Aneta

    2016-02-01

    Within this research, a headspace (HS) gas chromatography-flame ionization detector-mass spectrometry method was developed for profiling of residual solvents (RSs) in active pharmaceutical ingredients (APIs). Design of experiment was used for optimization of sample preparation, as well as for robustness testing of the method. HS equilibration temperature and dilution medium were detected as parameters with greater impact on the sensitivity, compared with the time used for equilibration of the samples. Regardless of the sample solubility, the use of water for sample preparation was found to be crucial for better sensitivity. The use of a well-designed strategy for method development and robustness testing, additional level of identification confidence, as well as use of internal standard provided a strong and reliable analytical tool for API fingerprinting, thus enabling the authentication of the substance based on the RS profile.

  13. Optimization Of The Alternate Cycle In A Membrane Aeration/Filtration Combined Bioreactor

    NASA Astrophysics Data System (ADS)

    Wang, Hongjie; Dong, Wenyi; Yang, Yue; Gan, Guanghua; Li, Weiguang

    2010-11-01

    In this study, a membrane aeration/filtration combined bioreactor (CMBR) was constructed, and the effect of alternate cycle by CMBR on membrane fouling and oxygen utilization efficiency (OUE) was investigated. Results showed that under the condition, when the alternate cycle was 0.75˜3h, the ΔTMP (TMP value of the time when a filtration cycle was over) of CMBR maintained a basically constant value during the 6 days' continuous operation, which implied the CMBR achieved a favorable effect of the membrane fouling relieving. Too short or too long cycle would lead to a gradual increase of ΔTMP. OUE of CMBR increased with the extension of the alternate cycle. Thus, it suggested that the optimal alternate cycle of CMBR should be 3h.

  14. Heuristic optimization of pressurized water reactor fuel cycle design under general constraints

    SciTech Connect

    Moon, H.; Levine, S.H. ); Mahgerefteh, M. )

    1989-12-01

    Optimization techniques in fuel management have directed modern fuel cycle designs to use low-leakage loading patterns. Future optimization calculations involving low-leakage patterns must utilize nucleonic models that are both fast operationally and rigorous. A two-dimensional two-group diffusion theory code is developed and lattice homogenization constants are generated using a modified LEOPARD code to fulfill these criteria. Based on these two codes, a heuristic optimization study is performed that considers the general constraints (e.g., spent-fuel storage limit and mechanical burnup limit) given to a utility fuel cycle designer. The optimum cycle length that minimizes the fuel cost is {approximately} 600 effective full-power days for the conditions assumed.

  15. The evolution of life cycle complexity in aphids: Ecological optimization or historical constraint?

    PubMed

    Hardy, Nate B; Peterson, Daniel A; von Dohlen, Carol D

    2015-06-01

    For decades, biologists have debated why many parasites have obligate multihost life cycles. Here, we use comparative phylogenetic analyses of aphids to evaluate the roles of ecological optimization and historical constraint in the evolution of life cycle complexity. If life cycle complexity is adaptive, it should be evolutionarily labile, that is, change in response to selection. We provide evidence that this is true in some aphids (aphidines), but not others (nonaphidines)-groups that differ in the intensity of their relationships with primary hosts. Next, we test specific mechanisms by which life cycle complexity could be adaptive or a constraint. We find that among aphidines there is a strong association between complex life cycles and polyphagy but only a weak correlation between life cycle complexity and reproductive mode. In contrast, among nonaphidines the relationship between life cycle complexity and host breadth is weak but the association between complex life cycles and sexual reproduction is strong. Thus, although the adaptiveness of life cycle complexity appears to be lineage specific, across aphids, life cycle evolution appears to be tightly linked with the evolution of other important natural history traits.

  16. Optimal cure cycle design of a resin-fiber composite laminate

    NASA Technical Reports Server (NTRS)

    Hou, Jean W.; Sheen, Jeenson

    1987-01-01

    A unified computed aided design method was studied for the cure cycle design that incorporates an optimal design technique with the analytical model of a composite cure process. The preliminary results of using this proposed method for optimal cure cycle design are reported and discussed. The cure process of interest is the compression molding of a polyester which is described by a diffusion reaction system. The finite element method is employed to convert the initial boundary value problem into a set of first order differential equations which are solved simultaneously by the DE program. The equations for thermal design sensitivities are derived by using the direct differentiation method and are solved by the DE program. A recursive quadratic programming algorithm with an active set strategy called a linearization method is used to optimally design the cure cycle, subjected to the given design performance requirements. The difficulty of casting the cure cycle design process into a proper mathematical form is recognized. Various optimal design problems are formulated to address theses aspects. The optimal solutions of these formulations are compared and discussed.

  17. Maximum power, ecological function and efficiency of an irreversible Carnot cycle: a cost and effectiveness optimization

    NASA Astrophysics Data System (ADS)

    Aragón-González, G.; Canales-Palma, A.; León-Galicia, A.; Morales-Gómez, J. R.

    2008-12-01

    In this work we include, for the Carnot cycle, irreversibilities of linear finite rate of heat transferences between the heat engine and its reservoirs, heat leak between the reservoirs and internal dissipations of the working fluid. A first optimization of the power output, the efficiency and ecological function of an irreversible Carnot cycle, with respect to: internal temperature ratio, time ratio for the heat exchange and the allocation ratio of the heat exchangers; is performed. For the second and third optimizations, the optimum values for the time ratio and internal temperature ratio are substituted into the equation of power and, then, the optimizations with respect to the cost and effectiveness ratio of the heat exchangers are performed. Finally, a criterion of partial optimization for the class of irreversible Carnot engines is herein presented.

  18. Optimization process condition for deacidification of palm oil by liquid-liquid extraction using NADES (Natural Deep Eutectic Solvent)

    NASA Astrophysics Data System (ADS)

    Israyandi, Zahrina, Ida; Mulia, Kamarza

    2017-03-01

    One of many steps in palm oil refining process is deacidification which aims to separate free fatty acids and other compounds from the oil. The deacidification process was using a green solvent, known as NADES, that consisted of betaine monohydrate and propionic acid at molar ratio of 1:8. In this study, the process conditions were optimized using the response surface method (RSM) through central composite design in order to predict the maximum distribution coefficient of palmitic acid. The obtained regression equation of the basic model for optimization was: y = 0.717 + 0.003x1 + 0.043 x2 + 0.148x3 - 0.005 x1x1 - 0.030 x2x2 + 0.047 x3x3 - 0.008 x1x2 + 0.008 x1x3 + 0.033 x2x3. The independent variables are x1 ≡ temperature (40, 60, 80 °C), x2≡ amount of palmitic acid in the palm oil (2, 5, 8 %) and x3 ≡ mass ratios of oil to NADES (1:2, 1:1, 2:1). The optimum process condition found was temperature of 62.3°C, palmitic acid content of 8%, and NADES to palm oil mass ratio of 1:2, resulting in the maximum distribution coefficient of 0.96.

  19. Optimization and application of homogeneous liquid-liquid extraction in preconcentration of copper (II) in a ternary solvent system.

    PubMed

    Farajzadeh, Mir Ali; Bahram, Morteza; Zorita, Saioa; Mehr, Behzad Ghorbani

    2009-01-30

    In this study a homogeneous liquid-liquid extraction based on the Ph-dependent phase-separation process was investigated using a ternary solvent system (water-acetic acid-chloroform) for the preconcentration of Cu(2+) ions. 8-Hydroxy quinoline was used as the chelating agent prior to its extraction. Flame atomic absorption spectrophotometry using acetylene-air flame was used for the quantitation of analyte after preconcentration. The effect of various experimental parameters in extraction step was investigated using two optimization methods, one variable at a time and central composite design. The experimental design was done at five levels of operating parameters. Nearly the same optimized results were obtained using both methods: sample size, 5 mL; volume of NaOH 10 M, 2 mL; chloroform volume, 300 microL; 8-hydroxy quinoline concentration more than 0.01 M and salt amount did not affect the extraction significantly. Under the optimum conditions the calibration graph was linear over the range 10-2000 microg L(-1). The relative standard deviation was 7.6% for six repeated determinations (C = 500 microg L(-1)). Furthermore, the limit of detection (S/N=3) and limit of quantification (S/N=10) of the method were obtained as 1.74 and 6 microg L(-1), respectively.

  20. Optimal cure cycle design for autoclave processing of thick composites laminates: A feasibility study

    NASA Technical Reports Server (NTRS)

    Hou, Jean W.

    1985-01-01

    The thermal analysis and the calculation of thermal sensitivity of a cure cycle in autoclave processing of thick composite laminates were studied. A finite element program for the thermal analysis and design derivatives calculation for temperature distribution and the degree of cure was developed and verified. It was found that the direct differentiation was the best approach for the thermal design sensitivity analysis. In addition, the approach of the direct differentiation provided time histories of design derivatives which are of great value to the cure cycle designers. The approach of direct differentiation is to be used for further study, i.e., the optimal cycle design.

  1. Optimal timing for performing hysterectomy according to different phase of menstrual cycle: Which is best?

    PubMed

    Kim, Jeong Jin; Kang, Jun Hyeok; Lee, Kyo Won; Kim, Kye Hyun; Song, Taejong

    2017-03-13

    The aim of this study was to determine whether the different phases of the menstrual cycle could affect operative bleeding in women undergoing laparoscopic hysterectomy. This was a retrospective comparative study. Based on the adjusted day of menstrual cycle, 212 women who underwent laparoscopic hysterectomy were classified into three groups: the follicular phase (n = 51), luteal phase group (n = 125), and menstruation group (n = 36). The primary outcome measure was the operative bleeding. There was no difference in the baseline characteristics of the patients belonging to the three groups. For the groups, there were no significant differences in operative bleeding (p = .469) and change in haemoglobin (p = .330), including operative time, length of hospital stay and complications. The menstrual cycle did not affect the operative bleeding and other parameters. Therefore, no phase of the menstrual cycle could be considered as an optimal timing for performing laparoscopic hysterectomy with minimal operative bleeding. Impact statement What is already known on this subject: the menstrual cycle results in periodic changes in haemostasis and blood flow in the reproductive organs. What the results of this study add: the menstrual cycle did not affect the operative bleeding and other operative parameters during laparoscopic hysterectomy. What the implications are of these findings for clinical practice and/or further research: no phase of the menstrual cycle could be considered as an optimal timing for performing laparoscopic hysterectomy with minimal operative bleeding.

  2. Sensitivity Analysis and Optimization of the Nuclear Fuel Cycle: A Systematic Approach

    NASA Astrophysics Data System (ADS)

    Passerini, Stefano

    For decades, nuclear energy development was based on the expectation that recycling of the fissionable materials in the used fuel from today's light water reactors into advanced (fast) reactors would be implemented as soon as technically feasible in order to extend the nuclear fuel resources. More recently, arguments have been made for deployment of fast reactors in order to reduce the amount of higher actinides, hence the longevity of radioactivity, in the materials destined to a geologic repository. The cost of the fast reactors, together with concerns about the proliferation of the technology of extraction of plutonium from used LWR fuel as well as the large investments in construction of reprocessing facilities have been the basis for arguments to defer the introduction of recycling technologies in many countries including the US. In this thesis, the impacts of alternative reactor technologies on the fuel cycle are assessed. Additionally, metrics to characterize the fuel cycles and systematic approaches to using them to optimize the fuel cycle are presented. The fuel cycle options of the 2010 MIT fuel cycle study are re-examined in light of the expected slower rate of growth in nuclear energy today, using the CAFCA (Code for Advanced Fuel Cycle Analysis). The Once Through Cycle (OTC) is considered as the base-line case, while advanced technologies with fuel recycling characterize the alternative fuel cycle options available in the future. The options include limited recycling in L WRs and full recycling in fast reactors and in high conversion LWRs. Fast reactor technologies studied include both oxide and metal fueled reactors. Additional fuel cycle scenarios presented for the first time in this work assume the deployment of innovative recycling reactor technologies such as the Reduced Moderation Boiling Water Reactors and Uranium-235 initiated Fast Reactors. A sensitivity study focused on system and technology parameters of interest has been conducted to test

  3. Assessment and optimization of an ultrasound-assisted washing process using organic solvents for polychlorinated biphenyl-contaminated soil.

    PubMed

    Bezama, Alberto; Flores, Alejandra; Araneda, Alberto; Barra, Ricardo; Pereira, Eduardo; Hernández, Víctor; Moya, Heriberto; Konrad, Odorico; Quiroz, Roberto

    2013-10-01

    The goal of this work was to evaluate a washing process that uses organic solutions for polychlorinated biphenyl (PCB)-contaminated soil, and includes an ultrasound pre-treatment step to reduce operational times and organic solvent losses. In a preliminary trial, the suitability of 10 washing solutions of different polarities were tested, from which three n-hexane-based solutions were selected for further evaluation. A second set of experiments was designed using a three-level Taguchi L27 orthogonal array to model the desorption processes of seven different PCB congeners in terms of the variability of their PCB concentration levels, polarity of the washing solution, sonication time, the ratio washing solution/soil, number of extraction steps and total washing time. Linear models were developed for the desorption processes of all congeners. These models provide a good fit with the results obtained. Moreover, statistically significant outcomes were achieved from the analysis of variance tests carried out. It was determined that sonication time and ratio of washing solution/soil were the most influential process parameters. For this reason they were studied in a third set of experiments, constructed as a full factorial design. The process was eventually optimized, achieving desorption rates of more than 90% for all congeners, thus obtaining concentrations lower than 5 ppb in all cases. The use of an ultrasound-assisted soil washing process for PCB-contaminated soils that uses organic solvents seems therefore to be a viable option, especially with the incorporation of an extra step in the sonication process relating to temperature control, which is intended to prevent the loss of the lighter congeners.

  4. A new thermostable and organic solvent-tolerant lipase from Staphylococcus warneri; optimization of media and production conditions using statistical methods.

    PubMed

    Yele, Viraj U; Desai, Krutika

    2015-01-01

    A new thermostable and solvent-tolerant lipase was isolated from newly isolated Staphylococcus warneri from oil-contaminated soil. Optimization of the fermentation media for production of thermostable and organic solvent-tolerant lipase was carried out using two statistical methods, i.e., Plackett-Burman design (PBD) and central composite design (CCD) were used for the optimization of the media components. PBD was used to efficiently select important medium components affecting the lipase production. Out of 15 medium components screened, four components, i.e., olive oil, peptone, maltose, and K2HPO4 were found to contribute positively to lipase production. CCD and response surface methodology (RSM) were used to determine the optimum levels of the selected components using Design-Expert 8.0 software. Production medium with olive oil (1.45 %), peptone (0.28 %), maltose (0.054 %), and K2HPO4 (0.091 %) was optimized with a maximum lipase production of 10.43 IU/ml/min. Similarly, production conditions for the lipase production were optimized by using CCD and RSM. Optimized conditions were found to have an incubation temperature of 55 °C, medium pH of 8.0, agitation of 120 rpm, and inoculum volume of 2 %. RSM revealed the maximum lipase production of 17.21 IU/ml using these optimized production conditions. Crude lipase showed enhanced activity in organic solvents such as diethyl ether, hexane, and cyclohexane.

  5. Coordinated optimization of the parameters of the cooled gas-turbine flow path and the parameters of gas-turbine cycles and combined-cycle power plants

    NASA Astrophysics Data System (ADS)

    Kler, A. M.; Zakharov, Yu. B.; Potanina, Yu. M.

    2014-06-01

    In the present paper, we evaluate the effectiveness of the coordinated solution to the optimization problem for the parameters of cycles in gas turbine and combined cycle power plants and to the optimization problem for the gas-turbine flow path parameters within an integral complex problem. We report comparative data for optimizations of the combined cycle power plant at coordinated and separate optimizations, when, first, the gas turbine and, then, the steam part of a combined cycle plant is optimized. The comparative data are presented in terms of economic indicators, energy-effectiveness characteristics, and specific costs. Models that were used in the present study for calculating the flow path enable taking into account, as a factor influencing the economic and energy effectiveness of the power plant, the heat stability of alloys from which the nozzle and rotor blades of gas-turbine stages are made.

  6. Entransy and exergy analyses for optimizations of heat-work conversion with carnot cycle

    NASA Astrophysics Data System (ADS)

    Han, Chul Ho; Kim, Kyoung Hoon

    2016-06-01

    The concept of entransy has been newly proposed in terms of the analogy between heat and electrical conduction and could be useful in analyzing and optimizing the heat-work conversion systems. This work presents comparative analyses of entransy and exergy for optimizations of heat-work conversion. The work production and heat transfer processes in Carnot cycle system are investigated with the formulations of exergy destruction, entransy loss, work entransy, entransy dissipation, and efficiencies for both cases of dumping and non-dumping of used source fluid. The effects of source and condensation temperatures on the system performance are systematically investigated for optimal condition of producing maximum work or work entransy.

  7. The optimization air separation plants for combined cycle MHD-power plant applications

    NASA Technical Reports Server (NTRS)

    Juhasz, A. J.; Springmann, H.; Greenberg, R.

    1980-01-01

    Some of the design approaches being employed during a current supported study directed at developing an improved air separation process for the production of oxygen enriched air for magnetohydrodynamics (MHD) combustion are outlined. The ultimate objective is to arrive at conceptual designs of air separation plants, optimized for minimum specific power consumption and capital investment costs, for integration with MHD combined cycle power plants.

  8. Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

    NASA Astrophysics Data System (ADS)

    Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

    2016-02-01

    A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

  9. Optimal Design and Operation of Helium Refrigeration Systems Using the Ganni Cycle

    NASA Astrophysics Data System (ADS)

    Ganni, V.; Knudsen, P.

    2010-04-01

    The constant pressure ratio process, as implemented in the floating pressure—Ganni cycle, is a new variation to prior cryogenic refrigeration and liquefaction cycle designs that allows for optimal operation and design of helium refrigeration systems. This cycle is based upon the traditional equipment used for helium refrigeration system designs, i.e., constant volume displacement compression and critical flow expansion devices. It takes advantage of the fact that for a given load, the expander sets the compressor discharge pressure and the compressor sets its own suction pressure. This cycle not only provides an essentially constant system Carnot efficiency over a wide load range, but invalidates the traditional philosophy that the (`TS') design condition is the optimal operating condition for a given load using the as-built hardware. As such, the Floating Pressure-Ganni Cycle is a solution to reduce the energy consumption while increasing the reliability, flexibility and stability of these systems over a wide operating range and different operating modes and is applicable to most of the existing plants. This paper explains the basic theory behind this cycle operation and contrasts it to the traditional operational philosophies presently used.

  10. OPTIMAL DESIGN AND OPERATION OF HELIUM REFRIGERATION SYSTEMS USING THE GANNI CYCLE

    SciTech Connect

    Venkatarao Ganni, Peter Knudsen

    2010-04-01

    The constant pressure ratio process, as implemented in the floating pressure - Ganni cycle, is a new variation to prior cryogenic refrigeration and liquefaction cycle designs that allows for optimal operation and design of helium refrigeration systems. This cycle is based upon the traditional equipment used for helium refrigeration system designs, i.e., constant volume displacement compression and critical flow expansion devices. It takes advantage of the fact that for a given load, the expander sets the compressor discharge pressure and the compressor sets its own suction pressure. This cycle not only provides an essentially constant system Carnot efficiency over a wide load range, but invalidates the traditional philosophy that the (‘TS’) design condition is the optimal operating condition for a given load using the as-built hardware. As such, the Floating Pressure- Ganni Cycle is a solution to reduce the energy consumption while increasing the reliability, flexibility and stability of these systems over a wide operating range and different operating modes and is applicable to most of the existing plants. This paper explains the basic theory behind this cycle operation and contrasts it to the traditional operational philosophies presently used.

  11. Reducing California's Greenhouse Gas Emissions through ProductLife-Cycle Optimization

    SciTech Connect

    Masanet, Eric; Price, Lynn; de la Rue du Can, Stephane; Worrell,Ernst

    2005-12-30

    Product life-cycle optimization addresses the reduction ofenvironmental burdens associated with the production, use, andend-of-life stages of a product s life cycle. In this paper, we offer anevaluation of the opportunities related to product life-cycleoptimization in California for two key products: personal computers (PCs)and concrete. For each product, we present the results of an explorativecase study to identify specific opportunities for greenhouse gas (GHG)emissions reductions at each stage of the product life cycle. We thenoffer a discussion of the practical policy options that may exist forrealizing the identified GHG reduction opportunities. The case studiesdemonstrate that there may be significant GHG mitigation options as wellas a number of policy options that could lead to life-cycle GHG emissionsreductions for PCs and concrete in California.

  12. Optimal thermoeconomic performance of an irreversible regenerative ferromagnetic Ericsson refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Xu, Zhichao; Guo, Juncheng; Lin, Guoxing; Chen, Jincan

    2016-07-01

    On the basis of the Langevin theory of classical statistical mechanics, the magnetization, entropy, and iso-field heat capacity of ferromagnetic materials are analyzed and their mathematical expressions are derived. An irreversible regenerative Ericsson refrigeration cycle by using a ferromagnetic material as the working substance is established, in which finite heat capacity rates of low and high temperature reservoirs, non-perfect regenerative heat of the refrigeration cycle, additional regenerative heat loss, etc. are taken into account. Based on the regenerative refrigeration cycle model, a thermoeconomic function is introduced as one objective function and optimized with respect to the temperatures of the working substance in the two iso-thermal processes. By means of numerical calculation, the effects of the effective factor of the heat exchangers in high/low temperature reservoir sides, efficiency of the regenerator, heat capacity rate of the low temperature reservoir, and applied magnetic field on the optimal thermoeconomic function as well as the corresponding cooling rate and coefficient of performance are revealed. The results obtained in this paper can provide some theoretical guidance for the optimal design of actual regenerative magnetic refrigerator cycle.

  13. Blastocyst culture and cryopreservation to optimize clinical outcomes of warming cycles.

    PubMed

    Zhu, Lixia; Xi, Qingsong; Zhang, Hanwang; Li, Yufeng; Ai, Jihui; Jin, Lei

    2013-08-01

    Surplus embryos available for cryopreservation in fresh cycles are considered as having good potential for future use. However, the optimal stage of embryo cryopreservation remains unclear. In this study, 1190 patients with surplus embryos on day 3 were divided into two groups: cleavage-stage embryo cryopreservation (control group) and blastocyst cryopreservation (blastocyst group). The clinical outcomes of the subsequent warming cycles were evaluated. The proportion of cycles with blastocyst formation was 73.8% in the blastocyst group. Although in the blastocyst group, the cancellation rate of blastocyst transfer was increased due to lack of blastocysts available for cryopreservation, the blastocyst group achieved significantly higher rates of clinical pregnancy/cycle (43.2% versus 34.9%; P=0.003), pregnancy/transfer (59.5% versus 35.4%; P<0.001) and implantation (46.5% versus 22.2%; P<0.001) from the first warming cycle compared with the control group. In an embryo-number classified analysis, the clinical pregnancy rate was also higher in the blastocyst group. However, the cumulative pregnancy was similar between the two groups. Blastocyst culture as an embryo selection tool will not improve embryo viability but it will help patients to achieve pregnancy more quickly. Extended culture of surplus embryos to the blastocyst stage for cryopreservation optimizes the clinical outcomes.

  14. Computerized systems analysis and optimization of aircraft engine performance, weight, and life cycle costs

    NASA Technical Reports Server (NTRS)

    Fishbach, L. H.

    1980-01-01

    The computational techniques are described which are utilized at Lewis Research Center to determine the optimum propulsion systems for future aircraft applications and to identify system tradeoffs and technology requirements. Cycle performance, and engine weight can be calculated along with costs and installation effects as opposed to fuel consumption alone. Almost any conceivable turbine engine cycle can be studied. These computer codes are: NNEP, WATE, LIFCYC, INSTAL, and POD DRG. Examples are given to illustrate how these computer techniques can be applied to analyze and optimize propulsion system fuel consumption, weight and cost for representative types of aircraft and missions.

  15. Optimization of wave rotors for use as gas turbine engine topping cycles

    NASA Technical Reports Server (NTRS)

    Wilson, Jack; Paxson, Daniel E.

    1995-01-01

    Use of a wave rotor as a topping cycle for a gas turbine engine can improve specific power and reduce specific fuel consumption. Maximum improvement requires the wave rotor to be optimized for best performance at the mass flow of the engine. The optimization is a trade-off between losses due to friction and passage opening time, and rotational effects. An experimentally validated, one-dimensional CFD code, which includes these effects, has been used to calculate wave rotor performance, and find the optimum configuration. The technique is described, and results given for wave rotors sized for engines with sea level mass flows of 4, 26, and 400 lb/sec.

  16. Construction and optimization of a quantum analog of the Carnot cycle.

    PubMed

    Xiao, Gaoyang; Gong, Jiangbin

    2015-07-01

    The quantum analog of Carnot cycles in few-particle systems consists of two quantum adiabatic steps and two isothermal steps. This construction is formally justified by use of a minimum work principle. It is then shown, using minimal assumptions of work or heat in nanoscale systems, that the heat-to-work efficiency of such quantum heat engine cycles can be further optimized via two conditions regarding the expectation value of some generalized force operators evaluated at equilibrium states. In general the optimized efficiency is system specific, lower than the Carnot efficiency, and dependent upon both temperatures of the cold and hot reservoirs. Simple computational examples are used to illustrate our theory. The results should be an important guide towards the design of favorable working conditions of a realistic quantum heat engine.

  17. Construction and optimization of a quantum analog of the Carnot cycle

    NASA Astrophysics Data System (ADS)

    Xiao, Gaoyang; Gong, Jiangbin

    2015-07-01

    The quantum analog of Carnot cycles in few-particle systems consists of two quantum adiabatic steps and two isothermal steps. This construction is formally justified by use of a minimum work principle. It is then shown, using minimal assumptions of work or heat in nanoscale systems, that the heat-to-work efficiency of such quantum heat engine cycles can be further optimized via two conditions regarding the expectation value of some generalized force operators evaluated at equilibrium states. In general the optimized efficiency is system specific, lower than the Carnot efficiency, and dependent upon both temperatures of the cold and hot reservoirs. Simple computational examples are used to illustrate our theory. The results should be an important guide towards the design of favorable working conditions of a realistic quantum heat engine.

  18. Optimization of the performance characteristics in an irreversible magnetic Ericsson refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Xia, Z. R.; Ye, X. M.; Lin, G. X.; Brück, E.

    2006-05-01

    A general model of an irreversible Ericsson refrigeration cycle employing paramagnetic materials as the working substance is presented, in which multi-irreversibilities such as finite-rate heat transfer, regenerative loss, heat leak, efficiency of regenerator and internal irreversibility resulting from magnetic working substances are taken into account. On the basis of the general thermodynamic properties of paramagnetic materials and the optimal-control theory, the optimal mathematical expressions of cooling load, coefficient of performance and power input of the irreversible Ericsson refrigeration cycle using paramagnetic materials as the working substance are derived. By means of a numerical approach, the influence of the heat leak, the internal irreversibility, the efficiency of regenerator, the ratio of the magnetic fields on the cyclic performance characteristics of the refrigeration cycle are revealed and discussed in detail. Some important performance bounds, e.g. the maximum cooling load and the corresponding coefficient of performance, the maximum coefficient of performance and the corresponding cooling load, are determined and evaluated. Furthermore, several special cases may be deduced from the primary results in this paper. The conclusions obtained in the present paper are more general and useful than those existing in literature and can provide some new important information for the optimal design and performance improvement of magnetic refrigerators.

  19. Applicability of the minimum entropy generation method for optimizing thermodynamic cycles

    NASA Astrophysics Data System (ADS)

    Cheng, Xue-Tao; Liang, Xin-Gang

    2013-01-01

    Entropy generation is often used as a figure of merit in thermodynamic cycle optimizations. In this paper, it is shown that the applicability of the minimum entropy generation method to optimizing output power is conditional. The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power when the total heat into the system of interest is not prescribed. For the cycles whose working medium is heated or cooled by streams with prescribed inlet temperatures and prescribed heat capacity flow rates, it is theoretically proved that both the minimum entropy generation rate and the minimum entropy generation number correspond to the maximum output power when the virtual entropy generation induced by dumping the used streams into the environment is considered. However, the minimum principle of entropy generation is not tenable in the case that the virtual entropy generation is not included, because the total heat into the system of interest is not fixed. An irreversible Carnot cycle and an irreversible Brayton cycle are analysed. The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power if the heat into the system of interest is not prescribed.

  20. Crude extract and solvent fractions of Calystegia soldanella induce G1 and S phase arrest of the cell cycle in HepG2 cells

    PubMed Central

    Lee, Jung Im; Kim, In-Hye; Nam, Taek-Jeong

    2017-01-01

    The representative halophyte Calystegia soldanella (L) Roem. et Schult is a perennial vine herb that grows in coastal dunes throughout South Korea as well as in other regions around the world. This plant has long been used as an edible and medicinal herb to cure rheumatic arthritis, sore throat, dropsy, and scurvy. Some studies have also shown that this plant species exhibits various biological activities. However, there are few studies on cytotoxicity induced by C. soldanella treatment in HepG2 human hepatocellular carcinoma cells. In this study, we investigated the viability of HepG2 cells following treatment with crude extracts and four solvent-partitioned fractions of C. soldanella. Of the crude extract and four solvent fractions tested, treatment with the 85% aqueous methanol (aq. MeOH) fraction resulted in the greatest inhibition of HepG2 cell proliferation. Flow cytometry showed that the 85% aq. MeOH fraction induced a G0/G1 and S phase arrest of the cell cycle progression. The 85% aq. MeOH fraction arrested HepG2 cells at the G0/G1 phase in a concentration-dependent manner, and resulted in decreased expression of cyclin D1, cyclin E, cyclin-dependent kinase (CDK)2, CDK4, CDK6, p21, and p27. Additionally, the 85% aq. MeOH fraction treatment also arrested HepG2 cells in the S phase, with decreased expression of cyclin A, CDK2, and CDC25A. Also, treatment with this fraction reduced the expression of retinoblastoma (RB) protein and the transcription factor E2F. These results suggest that the 85% aq. MeOH fraction exhibits potential anticancer activity in HepG2 cells by inducing G0/G1 and S phase arrest of the cell cycle. PMID:28101580

  1. A viscous solvent enables information transfer from gene-length nucleic acids in a model prebiotic replication cycle

    NASA Astrophysics Data System (ADS)

    He, Christine; Gállego, Isaac; Laughlin, Brandon; Grover, Martha A.; Hud, Nicholas V.

    2016-10-01

    Many hypotheses concerning the nature of early life assume that genetic information was once transferred through the template-directed synthesis of RNA, before the emergence of coded enzymes. However, attempts to demonstrate enzyme-free, template-directed synthesis of nucleic acids have been limited by 'strand inhibition', whereby transferring information from a template strand in the presence of its complementary strand is inhibited by the stability of the template duplex. Here, we use solvent viscosity to circumvent strand inhibition, demonstrating information transfer from a gene-length template (>300 nt) within a longer (545 bp or 3 kb) duplex. These results suggest that viscous environments on the prebiotic Earth, generated periodically by water evaporation, could have facilitated nucleic acid replication—particularly of long, structured sequences such as ribozymes. Our approach works with DNA and RNA, suggesting that viscosity-mediated replication is possible for a range of genetic polymers, perhaps even for informational polymers that may have preceded RNA.

  2. A viscous solvent enables information transfer from gene-length nucleic acids in a model prebiotic replication cycle.

    PubMed

    He, Christine; Gállego, Isaac; Laughlin, Brandon; Grover, Martha A; Hud, Nicholas V

    2017-04-01

    Many hypotheses concerning the nature of early life assume that genetic information was once transferred through the template-directed synthesis of RNA, before the emergence of coded enzymes. However, attempts to demonstrate enzyme-free, template-directed synthesis of nucleic acids have been limited by 'strand inhibition', whereby transferring information from a template strand in the presence of its complementary strand is inhibited by the stability of the template duplex. Here, we use solvent viscosity to circumvent strand inhibition, demonstrating information transfer from a gene-length template (>300 nt) within a longer (545 bp or 3 kb) duplex. These results suggest that viscous environments on the prebiotic Earth, generated periodically by water evaporation, could have facilitated nucleic acid replication-particularly of long, structured sequences such as ribozymes. Our approach works with DNA and RNA, suggesting that viscosity-mediated replication is possible for a range of genetic polymers, perhaps even for informational polymers that may have preceded RNA.

  3. Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Wang, Hao; Wu, GuoXing

    2012-02-01

    A model of the irreversible regenerative Brayton refrigeration cycle working with paramagnetic materials is established, in which the regeneration problem in two constant-magnetic field processes and the irreversibility in two adiabatic processes are considered synthetically. Expressions for the COP, cooling rate, power input, the minimum ratio of the two magnetic fields, etc., are derived. It is found that the influence of the irreversibility and the regeneration on the main performance parameters of the magnetic Brayton refrigerator is remarkable. It is important that we have obtained several optimal criteria, which may provide some theoretical basis for the optimal design and operation of the Brayton refrigerator. The results obtained in the paper can provide some new theoretical information for the optimal design and performance improvement of real Brayton refrigerators.

  4. Cost versus life cycle assessment-based environmental impact optimization of drinking water production plants.

    PubMed

    Capitanescu, F; Rege, S; Marvuglia, A; Benetto, E; Ahmadi, A; Gutiérrez, T Navarrete; Tiruta-Barna, L

    2016-07-15

    Empowering decision makers with cost-effective solutions for reducing industrial processes environmental burden, at both design and operation stages, is nowadays a major worldwide concern. The paper addresses this issue for the sector of drinking water production plants (DWPPs), seeking for optimal solutions trading-off operation cost and life cycle assessment (LCA)-based environmental impact while satisfying outlet water quality criteria. This leads to a challenging bi-objective constrained optimization problem, which relies on a computationally expensive intricate process-modelling simulator of the DWPP and has to be solved with limited computational budget. Since mathematical programming methods are unusable in this case, the paper examines the performances in tackling these challenges of six off-the-shelf state-of-the-art global meta-heuristic optimization algorithms, suitable for such simulation-based optimization, namely Strength Pareto Evolutionary Algorithm (SPEA2), Non-dominated Sorting Genetic Algorithm (NSGA-II), Indicator-based Evolutionary Algorithm (IBEA), Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D), Differential Evolution (DE), and Particle Swarm Optimization (PSO). The results of optimization reveal that good reduction in both operating cost and environmental impact of the DWPP can be obtained. Furthermore, NSGA-II outperforms the other competing algorithms while MOEA/D and DE perform unexpectedly poorly.

  5. Steady-state simulation and optimization of an integrated gasification combined cycle power plant with CO2 capture

    SciTech Connect

    Bhattacharyya, D.; Turton, R.; Zitney, S.

    2011-01-01

    Integrated gasification combined cycle (IGCC) plants are a promising technology option for power generation with carbon dioxide (CO2) capture in view of their efficiency and environmental advantages over conventional coal utilization technologies. This paper presents a three-phase, top-down, optimization-based approach for designing an IGCC plant with precombustion CO2 capture in a process simulator environment. In the first design phase, important global design decisions are made on the basis of plant-wide optimization studies with the aim of increasing IGCC thermal efficiency and thereby making better use of coal resources and reducing CO2 emissions. For the design of an IGCC plant with 90% CO2 capture, the optimal combination of the extent of carbon monoxide (CO) conversion in the water-gas shift (WGS) reactors and the extent of CO2 capture in the SELEXOL process, using dimethylether of polyethylene glycol as the solvent, is determined in the first phase. In the second design phase, the impact of local design decisions is explored considering the optimum values of the decision variables from the first phase as additional constraints. Two decisions are made focusing on the SELEXOL and Claus unit. In the third design phase, the operating conditions are optimized considering the optimum values of the decision variables from the first and second phases as additional constraints. The operational flexibility of the plant must be taken into account before taking final design decisions. Two studies on the operational flexibility of the WGS reactors and one study focusing on the operational flexibility of the sour water stripper (SWS) are presented. At the end of the first iteration, after executing all the phases once, the net plant efficiency (HHV basis) increases to 34.1% compared to 32.5% in a previously published study (DOE/NETL-2007/1281; National Energy Technology Laboratory, 2007). The study shows that the three-phase, top-down design approach presented is very

  6. Mixed solvents for the optimization of morphology in solution-processed, inverted-type perovskite/fullerene hybrid solar cells.

    PubMed

    Kim, Hak-Beom; Choi, Hyosung; Jeong, Jaeki; Kim, Seongbeom; Walker, Bright; Song, Seyeong; Kim, Jin Young

    2014-06-21

    We investigate mixed solvents of N,N-dimethylformamide (DMF) and γ-butyrolactone (GBL) to produce the smooth surface of a perovskite film and uniform crystal domains. This ideal morphology from mixed solvents enhances the power conversion efficiency to over 6% by improving the exciton dissociation efficiency and reducing the recombination loss at both interfaces of PEDOT:PSS/perovskite and perovskite/PCBM.

  7. Time Scale Optimization and the Hunt for Astronomical Cycles in Deep Time Strata

    NASA Astrophysics Data System (ADS)

    Meyers, Stephen R.

    2016-04-01

    A valuable attribute of astrochronology is the direct link between chronometer and climate change, providing a remarkable opportunity to constrain the evolution of the surficial Earth System. Consequently, the hunt for astronomical cycles in strata has spurred the development of a rich conceptual framework for climatic/oceanographic change, and has allowed exploration of the geologic record with unprecedented temporal resolution. Accompanying these successes, however, has been a persistent skepticism about appropriate astrochronologic testing and circular reasoning: how does one reliably test for astronomical cycles in stratigraphic data, especially when time is poorly constrained? From this perspective, it would seem that the merits and promise of astrochronology (e.g., a geologic time scale measured in ≤400 kyr increments) also serves as its Achilles heel, if the confirmation of such short rhythms defies rigorous statistical testing. To address these statistical challenges in astrochronologic testing, a new approach has been developed that (1) explicitly evaluates time scale uncertainty, (2) is resilient to common problems associated with spectrum confidence level assessment and 'multiple testing', and (3) achieves high statistical power under a wide range of conditions (it can identify astronomical cycles when present in data). Designated TimeOpt (for "time scale optimization"; Meyers 2015), the method employs a probabilistic linear regression model framework to investigate amplitude modulation and frequency ratios (bundling) in stratigraphic data, while simultaneously determining the optimal time scale. This presentation will review the TimeOpt method, and demonstrate how the flexible statistical framework can be further extended to evaluate (and optimize upon) complex sedimentation rate models, enhancing the statistical power of the approach, and addressing the challenge of unsteady sedimentation. Meyers, S. R. (2015), The evaluation of eccentricity

  8. Production of Alkaline Protease by Solvent-Tolerant Alkaliphilic Bacillus circulans MTCC 7942 Isolated from Hydrocarbon Contaminated Habitat: Process Parameters Optimization.

    PubMed

    Patil, Ulhas; Chaudhari, Ambalal

    2013-01-01

    In the present investigation, a newly isolated organic solvent-tolerant and alkaliphilic bacterial strain was reported from a hydrocarbon (gasoline and diesel) contaminated soil collected from the petrol station, Shirpur (India). The strain was identified as Bacillus circulans MTCC 7942, based on phenotype, biochemical, and phylogenetic analysis of 16S rRNA gene sequence. The capability of Bacillus circulans to secrete an extracellular, thermostable, alkaline protease and grow in the presence of organic solvents was explored. Bacillus circulans produced maximum alkaline protease (412 U/mL) in optimized medium (g/L): soybean meal, 15; starch, 10; KH2PO4, 1; MgSO4·7H2O, 0.05; CaCl2, 1; Na2CO3, 8; pH 10.0 at 37°C and 100 rpm. The competence of strain to grow in various organic solvents-n-octane, dodecane, n-decane, N,N-dimethylformamide, n-hexane, and dimethyl sulfoxide, establishes its potential as solvent-stable protease source for the possible applications in nonaqueous reactions and fine chemical synthesis.

  9. Optimized Solvent for Energy-Efficient, Environmentally-Friendly Capture of CO{sub 2} at Coal-Fired Power Plants

    SciTech Connect

    Farthing, G. A.; Rimpf, L. M.

    2014-04-30

    The overall goal of this project, as originally proposed, was to optimize the formulation of a novel solvent as a critical enabler for the cost-effective, energy-efficient, environmentally-friendly capture of CO{sub 2} at coal-fired utility plants. Aqueous blends of concentrated piperazine (PZ) with other compounds had been shown to exhibit high rates of CO{sub 2} absorption, low regeneration energy, and other desirable performance characteristics during an earlier 5-year development program conducted by B&W. The specific objective of this project was to identify PZ-based solvent formulations that globally optimize the performance of coal-fired power plants equipped with CO{sub 2} scrubbing systems. While previous solvent development studies have tended to focus on energy consumption and absorber size, important issues to be sure, the current work seeks to explore, understand, and optimize solvent formulation across the full gamut of issues related to commercial application of the technology: capital and operating costs, operability, reliability, environmental, health and safety (EH&S), etc. Work on the project was intended to be performed under four budget periods. The objective of the work in the first budget period has been to identify several candidate formulations of a concentrated PZ-based solvent for detailed characterization and evaluation. Work in the second budget period would generate reliable and comprehensive property and performance data for the identified formulations. Work in the third budget period would quantify the expected performance of the selected formulations in a commercial CO{sub 2} scrubbing process. Finally, work in the fourth budget period would provide a final technology feasibility study and a preliminary technology EH&S assessment. Due to other business priorities, however, B&W has requested that this project be terminated at the end of the first budget period. This document therefore serves as the final report for this project. It

  10. Genes adopt non-optimal codon usage to generate cell cycle-dependent oscillations in protein levels

    PubMed Central

    Frenkel-Morgenstern, Milana; Danon, Tamar; Christian, Thomas; Igarashi, Takao; Cohen, Lydia; Hou, Ya-Ming; Jensen, Lars Juhl

    2012-01-01

    The cell cycle is a temporal program that regulates DNA synthesis and cell division. When we compared the codon usage of cell cycle-regulated genes with that of other genes, we discovered that there is a significant preference for non-optimal codons. Moreover, genes encoding proteins that cycle at the protein level exhibit non-optimal codon preferences. Remarkably, cell cycle-regulated genes expressed in different phases display different codon preferences. Here, we show empirically that transfer RNA (tRNA) expression is indeed highest in the G2 phase of the cell cycle, consistent with the non-optimal codon usage of genes expressed at this time, and lowest toward the end of G1, reflecting the optimal codon usage of G1 genes. Accordingly, protein levels of human glycyl-, threonyl-, and glutamyl-prolyl tRNA synthetases were found to oscillate, peaking in G2/M phase. In light of our findings, we propose that non-optimal (wobbly) matching codons influence protein synthesis during the cell cycle. We describe a new mathematical model that shows how codon usage can give rise to cell-cycle regulation. In summary, our data indicate that cells exploit wobbling to generate cell cycle-dependent dynamics of proteins. PMID:22373820

  11. Adjusted Light and Dark Cycles Can Optimize Photosynthetic Efficiency in Algae Growing in Photobioreactors

    PubMed Central

    Sforza, Eleonora; Simionato, Diana; Giacometti, Giorgio Mario; Bertucco, Alberto; Morosinotto, Tomas

    2012-01-01

    Biofuels from algae are highly interesting as renewable energy sources to replace, at least partially, fossil fuels, but great research efforts are still needed to optimize growth parameters to develop competitive large-scale cultivation systems. One factor with a seminal influence on productivity is light availability. Light energy fully supports algal growth, but it leads to oxidative stress if illumination is in excess. In this work, the influence of light intensity on the growth and lipid productivity of Nannochloropsis salina was investigated in a flat-bed photobioreactor designed to minimize cells self-shading. The influence of various light intensities was studied with both continuous illumination and alternation of light and dark cycles at various frequencies, which mimic illumination variations in a photobioreactor due to mixing. Results show that Nannochloropsis can efficiently exploit even very intense light, provided that dark cycles occur to allow for re-oxidation of the electron transporters of the photosynthetic apparatus. If alternation of light and dark is not optimal, algae undergo radiation damage and photosynthetic productivity is greatly reduced. Our results demonstrate that, in a photobioreactor for the cultivation of algae, optimizing mixing is essential in order to ensure that the algae exploit light energy efficiently. PMID:22745696

  12. Adjusted light and dark cycles can optimize photosynthetic efficiency in algae growing in photobioreactors.

    PubMed

    Sforza, Eleonora; Simionato, Diana; Giacometti, Giorgio Mario; Bertucco, Alberto; Morosinotto, Tomas

    2012-01-01

    Biofuels from algae are highly interesting as renewable energy sources to replace, at least partially, fossil fuels, but great research efforts are still needed to optimize growth parameters to develop competitive large-scale cultivation systems. One factor with a seminal influence on productivity is light availability. Light energy fully supports algal growth, but it leads to oxidative stress if illumination is in excess. In this work, the influence of light intensity on the growth and lipid productivity of Nannochloropsis salina was investigated in a flat-bed photobioreactor designed to minimize cells self-shading. The influence of various light intensities was studied with both continuous illumination and alternation of light and dark cycles at various frequencies, which mimic illumination variations in a photobioreactor due to mixing. Results show that Nannochloropsis can efficiently exploit even very intense light, provided that dark cycles occur to allow for re-oxidation of the electron transporters of the photosynthetic apparatus. If alternation of light and dark is not optimal, algae undergo radiation damage and photosynthetic productivity is greatly reduced. Our results demonstrate that, in a photobioreactor for the cultivation of algae, optimizing mixing is essential in order to ensure that the algae exploit light energy efficiently.

  13. Thermodynamic analysis and optimization of fuel cell based Combined Cycle Cogeneration plant

    NASA Astrophysics Data System (ADS)

    Odukoya, Adedoyin

    Power plants operating in combined cycle cogeneration configuration are becoming increasingly popular because of high energy conversion efficiency and reduced pollutant and green-house gas emissions. On the other hand, fuel cell technology continues to be of global interest because it can operate with very low to 0% green-house gas emission depending on the fuel. The aim of the present work is to investigate the effect of co-firing of natural gas with synthetic gas generated from coal gasification on the thermodynamic performance of an air blown coal gasification Combined Cycle Cogeneration unit with a solid oxide fuel cell (SOFC) arrangement. The effects of the operating temperature of the SOFC and the pressure ratio and turbine inlet temperature of the gas turbine on the net work output and efficiency of the power cycles on the cogeneration unit are simulated. Simulations are also conducted on the thermal and cogeneration efficiencies of the individual power cycle as well as the overall plants respectively. The optimal pressure ratio, temperature of operation of the SOFC and, gas turbine inlet temperature was determined using a sequential quadratic program solver base on the Quasi-Newton algorithm.

  14. Multiparticle quantum Szilard engine with optimal cycles assisted by a Maxwell's demon

    NASA Astrophysics Data System (ADS)

    Cai, C. Y.; Dong, H.; Sun, C. P.

    2012-03-01

    We present a complete-quantum description of a multiparticle Szilard engine that consists of a working substance and a Maxwell's demon. The demon is modeled as a multilevel quantum system with specific quantum control, and the working substance consists of identical particles obeying Bose-Einstein or Fermi-Dirac statistics. In this description, a reversible scheme to erase the demon's memory by a lower-temperature heat bath is used. We demonstrate that (1) the quantum control of the demon can be optimized for a single-particle Szilard engine so that the efficiency of the demon-assisted thermodynamic cycle could reach the Carnot cycle's efficiency and (2) the low-temperature behavior of the working substance is very sensitive to the quantum statistics of the particles and the insertion position of the partition.

  15. Life cycle cost optimization of biofuel supply chains under uncertainties based on interval linear programming.

    PubMed

    Ren, Jingzheng; Dong, Liang; Sun, Lu; Goodsite, Michael Evan; Tan, Shiyu; Dong, Lichun

    2015-01-01

    The aim of this work was to develop a model for optimizing the life cycle cost of biofuel supply chain under uncertainties. Multiple agriculture zones, multiple transportation modes for the transport of grain and biofuel, multiple biofuel plants, and multiple market centers were considered in this model, and the price of the resources, the yield of grain and the market demands were regarded as interval numbers instead of constants. An interval linear programming was developed, and a method for solving interval linear programming was presented. An illustrative case was studied by the proposed model, and the results showed that the proposed model is feasible for designing biofuel supply chain under uncertainties.

  16. Life cycle analysis within pharmaceutical process optimization and intensification: case study of active pharmaceutical ingredient production.

    PubMed

    Ott, Denise; Kralisch, Dana; Denčić, Ivana; Hessel, Volker; Laribi, Yosra; Perrichon, Philippe D; Berguerand, Charline; Kiwi-Minsker, Lioubov; Loeb, Patrick

    2014-12-01

    As the demand for new drugs is rising, the pharmaceutical industry faces the quest of shortening development time, and thus, reducing the time to market. Environmental aspects typically still play a minor role within the early phase of process development. Nevertheless, it is highly promising to rethink, redesign, and optimize process strategies as early as possible in active pharmaceutical ingredient (API) process development, rather than later at the stage of already established processes. The study presented herein deals with a holistic life-cycle-based process optimization and intensification of a pharmaceutical production process targeting a low-volume, high-value API. Striving for process intensification by transfer from batch to continuous processing, as well as an alternative catalytic system, different process options are evaluated with regard to their environmental impact to identify bottlenecks and improvement potentials for further process development activities.

  17. Optimization of a NH4PF6-enhanced, non-organic solvent, dual microextraction method for determination of phthalate metabolites in urine by high performance liquid chromatography.

    PubMed

    Wu, Jia; Ye, Zhihan; Li, Xiaolong; Wang, Xuedong; Luo, Fangjun; Sheng, Bo; Li, Yiwei; Lyu, Jianxin

    2016-03-01

    In conventional ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) procedures, most of the IL disperser remains in the aqueous phase resulting in low recovery for moderately and weakly polar analytes due to the "carry-over effect". Herein, we successfully developed a "NH4PF6-enhanced, non-organic solvent, dual microextraction" method (ANSDM) for pretreatment of phthalate (PAE) metabolites with weak to moderate polarity. This method utilized in situ reaction of NH4PF6 as an ion-exchange reagent and disperser to realize two microextractions after using [C8MIM]PF6 as an extraction solvent and [C4MIM]BF4 as a disperser for conventional DLLME. Single-factor experiments, a two-level full factorial experimental design and central composite design were applied for optimizing operational parameters using 3D response surfaces and contour lines. Under optimized conditions, the newly developed method provided high extraction recoveries (93.8-99.1%) and low LODs (ca. 0.3μgL(-1)) for three phthalate metabolites in human urine. The primary advantages of the ANSDM method include: (1) integration of in situ reaction and conventional DLLME techniques to effectively extract both weak and moderately polar pollutants simultaneously; (2) non-organic solvent use in the microextraction procedure making the process safer and more environmental friendly; and (3) a time-saving, simple operation that is fully compatibility with HPLC analysis. To the best of our knowledge, our group is the first to develop the "non-organic solvent, dual microextraction" method and it has great potential as a sample pre-treatment technique for organic pollutants with weak to moderate polarity in biological and environmental matrices.

  18. Dose Finding of Small-Molecule Oncology Drugs: Optimization throughout the Development Life Cycle.

    PubMed

    Jänne, Pasi A; Kim, Geoffrey; Shaw, Alice T; Sridhara, Rajeshwari; Pazdur, Richard; McKee, Amy E

    2016-06-01

    In the current era of rapid marketing approval for promising new products in oncology, dose finding and optimization for small-molecule oncology drugs occurs throughout the development cycle and into the postmarketing setting. Many trials that support a regulatory application have high rates of dose reductions and discontinuations, which may result in postmarketing requirements (PMR) to study alternate doses or dosing schedules. Kinase inhibitors particularly have been susceptible to this problem, and among the 31 approved drugs of this class, the approvals of eight have included such PMRs and/or commitments. Thus, the current paradigm for dose finding and optimization could be improved. Newer strategies for dose finding rather than traditional 3 + 3 designs should be considered where feasible, and dose optimization should be continued after phase I and throughout development. Such strategies will increase the likelihood of a right dose for the right drug at the time of regulatory approval. Clin Cancer Res; 22(11); 2613-7. ©2016 AACR SEE ALL ARTICLES IN THIS CCR FOCUS SECTION, "NEW APPROACHES FOR OPTIMIZING DOSING OF ANTICANCER AGENTS".

  19. Evaluation of Externality Costs in Life-Cycle Optimization of Municipal Solid Waste Management Systems.

    PubMed

    Martinez-Sanchez, Veronica; Levis, James W; Damgaard, Anders; DeCarolis, Joseph F; Barlaz, Morton A; Astrup, Thomas F

    2017-03-21

    The development of sustainable solid waste management (SWM) systems requires consideration of both economic and environmental impacts. Societal life-cycle costing (S-LCC) provides a quantitative framework to estimate both economic and environmental impacts, by including "budget costs" and "externality costs". Budget costs include market goods and services (economic impact), whereas externality costs include effects outside the economic system (e.g., environmental impact). This study demonstrates the applicability of S-LCC to SWM life-cycle optimization through a case study based on an average suburban U.S. county of 500 000 people generating 320 000 Mg of waste annually. Estimated externality costs are based on emissions of CO2, CH4, N2O, PM2.5, PM10, NOx, SO2, VOC, CO, NH3, Hg, Pb, Cd, Cr (VI), Ni, As, and dioxins. The results indicate that incorporating S-LCC into optimized SWM strategy development encourages the use of a mixed waste material recovery facility with residues going to incineration, and separated organics to anaerobic digestion. Results are sensitive to waste composition, energy mix and recycling rates. Most of the externality costs stem from SO2, NOx, PM2.5, CH4, fossil CO2, and NH3 emissions. S-LCC proved to be a valuable tool for policy analysis, but additional data on key externality costs such as organic compounds emissions to water would improve future analyses.

  20. Integrating Hybrid Life Cycle Assessment with Multiobjective Optimization: A Modeling Framework.

    PubMed

    Yue, Dajun; Pandya, Shyama; You, Fengqi

    2016-02-02

    By combining life cycle assessment (LCA) with multiobjective optimization (MOO), the life cycle optimization (LCO) framework holds the promise not only to evaluate the environmental impacts for a given product but also to compare different alternatives and identify both ecologically and economically better decisions. Despite the recent methodological developments in LCA, most LCO applications are developed upon process-based LCA, which results in system boundary truncation and underestimation of the true impact. In this study, we propose a comprehensive LCO framework that seamlessly integrates MOO with integrated hybrid LCA. It quantifies both direct and indirect environmental impacts and incorporates them into the decision making process in addition to the more traditional economic criteria. The proposed LCO framework is demonstrated through an application on sustainable design of a potential bioethanol supply chain in the UK. Results indicate that the proposed hybrid LCO framework identifies a considerable amount of indirect greenhouse gas emissions (up to 58.4%) that are essentially ignored in process-based LCO. Among the biomass feedstock options considered, using woody biomass for bioethanol production would be the most preferable choice from a climate perspective, while the mixed use of wheat and wheat straw as feedstocks would be the most cost-effective one.

  1. A Multi-Cycle Q-Modulation for Dynamic Optimization of Inductive Links.

    PubMed

    Lee, Byunghun; Yeon, Pyungwoo; Ghovanloo, Maysam

    2016-08-01

    This paper presents a new method, called multi-cycle Q-modulation, which can be used in wireless power transmission (WPT) to modulate the quality factor (Q) of the receiver (Rx) coil and dynamically optimize the load impedance to maximize the power transfer efficiency (PTE) in two-coil links. A key advantage of the proposed method is that it can be easily implemented using off-the-shelf components without requiring fast switching at or above the carrier frequency, which is more suitable for integrated circuit design. Moreover, the proposed technique does not need any sophisticated synchronization between the power carrier and Q-modulation switching pulses. The multi-cycle Q-modulation is analyzed theoretically by a lumped circuit model, and verified in simulation and measurement using an off-the-shelf prototype. Automatic resonance tuning (ART) in the Rx, combined with multi-cycle Q-modulation helped maximizing PTE of the inductive link dynamically in the presence of environmental and loading variations, which can otherwise significantly degrade the PTE in multi-coil settings. In the prototype conventional 2-coil link, the proposed method increased the power amplifier (PA) plus inductive link efficiency from 4.8% to 16.5% at (RL = 1 kΩ, d23 = 3 cm), and from 23% to 28.2% at (RL = 100 Ω, d23 = 3 cm) after 11% change in the resonance capacitance, while delivering 168.1 mW to the load (PDL).

  2. Optimization of monitoring and inspections in the life-cycle of wind turbines

    NASA Astrophysics Data System (ADS)

    Hanish Nithin, Anu; Omenzetter, Piotr

    2016-04-01

    The past decade has witnessed a surge in the offshore wind farm developments across the world. Although this form of cleaner and greener energy is beneficial and eco-friendly, the production of wind energy entails high life-cycle costs. The costs associated with inspections, monitoring and repairs of wind turbines are primary contributors to the high costs of electricity produced in this way and are disadvantageous in today's competitive economic environment. There is limited research being done in the probabilistic optimization of life-cycle costs of offshore wind turbines structures and their components. This paper proposes a framework for assessing the life cycle cost of wind turbine structures subject to damage and deterioration. The objective of the paper is to develop a mathematical probabilistic cost assessment framework which considers deterioration, inspection, monitoring, repair and maintenance models and their uncertainties. The uncertainties are etched in the accuracy and precision of the monitoring and inspection methods and can be considered through the probability of damage detection of each method. Schedules for inspection, monitoring and repair actions are demonstrated using a decision tree. Examples of a generalised deterioration process integrated with the cost analysis using a decision tree are shown for a wind turbine foundation structure.

  3. Energy and exergy analyses of an integrated gasification combined cycle power plant with CO2 capture using hot potassium carbonate solvent.

    PubMed

    Li, Sheng; Jin, Hongguang; Gao, Lin; Mumford, Kathryn Anne; Smith, Kathryn; Stevens, Geoff

    2014-12-16

    Energy and exergy analyses were studied for an integrated gasification combined cycle (IGCC) power plant with CO2 capture using hot potassium carbonate solvent. The study focused on the combined impact of the CO conversion ratio in the water gas shift (WGS) unit and CO2 recovery rate on component exergy destruction, plant efficiency, and energy penalty for CO2 capture. A theoretical limit for the minimal efficiency penalty for CO2 capture was also provided. It was found that total plant exergy destruction increased almost linearly with CO2 recovery rate and CO conversion ratio at low CO conversion ratios, but the exergy destruction from the WGS unit and the whole plant increased sharply when the CO conversion ratio was higher than 98.5% at the design WGS conditions, leading to a significant decrease in plant efficiency and increase in efficiency penalty for CO2 capture. When carbon capture rate was over around 70%, via a combination of around 100% CO2 recovery rate and lower CO conversion ratios, the efficiency penalty for CO2 capture was reduced. The minimal efficiency penalty for CO2 capture was estimated to be around 5.0 percentage points at design conditions in an IGCC plant with 90% carbon capture. Unlike the traditional aim of 100% CO conversion, it was recommended that extremely high CO conversion ratios should not be considered in order to decrease the energy penalty for CO2 capture and increase plant efficiency.

  4. Production of Alkaline Protease by Solvent-Tolerant Alkaliphilic Bacillus circulans MTCC 7942 Isolated from Hydrocarbon Contaminated Habitat: Process Parameters Optimization

    PubMed Central

    Patil, Ulhas; Chaudhari, Ambalal

    2013-01-01

    In the present investigation, a newly isolated organic solvent-tolerant and alkaliphilic bacterial strain was reported from a hydrocarbon (gasoline and diesel) contaminated soil collected from the petrol station, Shirpur (India). The strain was identified as Bacillus circulans MTCC 7942, based on phenotype, biochemical, and phylogenetic analysis of 16S rRNA gene sequence. The capability of Bacillus circulans to secrete an extracellular, thermostable, alkaline protease and grow in the presence of organic solvents was explored. Bacillus circulans produced maximum alkaline protease (412 U/mL) in optimized medium (g/L): soybean meal, 15; starch, 10; KH2PO4, 1; MgSO4·7H2O, 0.05; CaCl2, 1; Na2CO3, 8; pH 10.0 at 37°C and 100 rpm. The competence of strain to grow in various organic solvents—n-octane, dodecane, n-decane, N,N-dimethylformamide, n-hexane, and dimethyl sulfoxide, establishes its potential as solvent-stable protease source for the possible applications in nonaqueous reactions and fine chemical synthesis. PMID:25937965

  5. iCycle: Integrated, multicriterial beam angle, and profile optimization for generation of coplanar and noncoplanar IMRT plans

    SciTech Connect

    Breedveld, Sebastiaan; Storchi, Pascal R. M.; Voet, Peter W. J.; Heijmen, Ben J. M.

    2012-02-15

    Purpose: To introduce iCycle, a novel algorithm for integrated, multicriterial optimization of beam angles, and intensity modulated radiotherapy (IMRT) profiles. Methods: A multicriterial plan optimization with iCycle is based on a prescription called wish-list, containing hard constraints and objectives with ascribed priorities. Priorities are ordinal parameters used for relative importance ranking of the objectives. The higher an objective priority is, the higher the probability that the corresponding objective will be met. Beam directions are selected from an input set of candidate directions. Input sets can be restricted, e.g., to allow only generation of coplanar plans, or to avoid collisions between patient/couch and the gantry in a noncoplanar setup. Obtaining clinically feasible calculation times was an important design criterium for development of iCycle. This could be realized by sequentially adding beams to the treatment plan in an iterative procedure. Each iteration loop starts with selection of the optimal direction to be added. Then, a Pareto-optimal IMRT plan is generated for the (fixed) beam setup that includes all so far selected directions, using a previously published algorithm for multicriterial optimization of fluence profiles for a fixed beam arrangement Breedveld et al.[Phys. Med. Biol. 54, 7199-7209 (2009)]. To select the next direction, each not yet selected candidate direction is temporarily added to the plan and an optimization problem, derived from the Lagrangian obtained from the just performed optimization for establishing the Pareto-optimal plan, is solved. For each patient, a single one-beam, two-beam, three-beam, etc. Pareto-optimal plan is generated until addition of beams does no longer result in significant plan quality improvement. Plan generation with iCycle is fully automated. Results: Performance and characteristics of iCycle are demonstrated by generating plans for a maxillary sinus case, a cervical cancer patient, and a

  6. Development and Utilization of mathematical Optimization in Advanced Fuel Cycle Systems Analysis

    SciTech Connect

    Turinsky, Paul; Hays, Ross

    2011-09-02

    Over the past sixty years, a wide variety of nuclear power technologies have been theorized, investigated and tested to various degrees. These technologies, if properly applied, could provide a stable, long-term, economical source of CO2-free electric power. However, the recycling of nuclear fuel introduces a degree of coupling between reactor systems which must be accounted for when making long term strategic plans. This work investigates the use of a simulated annealing optimization algorithm coupled together with the VISION fuel cycle simulation model in order to identify attractive strategies from economic, evironmental, non-proliferation and waste-disposal perspectives, which each have associated an objective function. The simulated annealing optimization algorithm works by perturbing the fraction of new reactor capacity allocated to each available reactor type (using a set of heuristic rules) then evaluating the resulting deployment scenario outcomes using the VISION model and the chosen objective functions. These new scenarios, which are either accepted or rejected according the the Metropolis Criterion, are then used as the basis for further perturbations. By repeating this process several thousand times, a family of near-optimal solutions are obtained. Preliminary results from this work using a two-step, Once-through LWR to Full-recycle/FRburner deployment scenario with exponentially increasing electric demand indicate that the algorithm is capable of nding reactor deployment pro les that reduce the long-term-heat waste disposal burden relative to an initial reference scenario. Further work is under way to re ne the current results and to extend them to include the other objective functions and to examine the optimization trade-o s that exist between these di erent objectives.

  7. Vibrational spectra of cysteine zwitterion and mechanism of its formation: bulk and specific solvent effects and geometry optimization in aqueous media.

    PubMed

    Tiwari, Saumya; Mishra, P C

    2009-08-15

    Vibrational spectrum of the zwitterionic (Z)-forms of cysteine has been studied considering full geometry optimization under the bulk solvent effect of aqueous media combined with the solvent effect of up to three specific water molecules. The tautomerization barrier energy of the molecule from its normal (N) to the Z form has also been obtained. Geometry optimization was performed at the B3LYP/AUG-cc-pVDZ level which was followed by single point energy calculations at the MP2/AUG-cc-pVDZ level of theory in both gas phase and aqueous media. Transition states (TS) were located between the N and Z-forms of cysteine complexed with one to three water molecules and also without any complexed water molecule. The bulk solvent effect of aqueous media was treated using the integral equation formalism of the polarizable continuum model (IEF-PCM). It has been found that the barrier energy decreases with the increasing number of complexed water molecules significantly. Two conformers (A, B) of Z-cysteine are found to have comparable stabilities. It is shown that agreement between the experimentally observed and our calculated vibrational frequencies for Z-cysteine, at the present level of treatment, is improved significantly for 22 out of 27 frequencies. For these 22 frequencies, for the more stable conformer (A) of Z-cysteine, the rms value of differences between our calculated and experimentally observed frequencies reduces from 22 to 11 cm(-1) in going from 0 to 3 complexed water molecules. Certain vibrational frequencies have been identified with the help of which the conformers A and B of Z cysteine can be identified.

  8. Expanded life-cycle analysis to optimize spacecraft life support system design

    NASA Astrophysics Data System (ADS)

    Russell, James F.

    The life-cycle of a human space mission begins with the conceptual design and ends with the return or disposal of the spacecraft. A major component of the spacecraft is the environmental control and life support system (ECLSS) that supports the crew. Historically, conceptual designs of ECLSS focused on launch costs; however, current missions with longer timelines have meaningful life cycle costs beyond launch costs. To reduce these costs, the author proposed an expanded life cycle analysis to optimize designs while meeting the somewhat contradictory goals for success and safety. Expanding the life cycle analysis of ECLSS, is particularly important, because space-habitat-maintenance has been anecdotally reported as taking time away from science activities on the International Space Station (ISS). To understand this potential issue, the author examined ISS crew time use and different approaches to ECLSS design. An analysis of ISS crew time use determined that each crew member spent at least 1.8 hours per day performing ISS maintenance tasks. Regardless of the confounding causal mechanisms, crew time spent on habitat maintenance on Skylab and ISS exceeded that estimated by design, thus reducing crew time allotted to perform other tasks, although not necessarily science. Upon further examination, analysis of ECLSS maintenance revealed that operational crew time estimates for the ISS mission design were low by an order of magnitude. A review of the literature indicates this work is the first time that design estimates were compared quantitatively to operational time and shown to be less for ECLSS. Based on these findings, Skylab and ISS missions were oversubscribed due to a mismatch between maintenance and operational time requirements. This mismatch most likely occurred, because only part of operational crew time was considered. Even with the inclusion of operational crew time, the ECLSS design for ISS may not have changed, but the ISS-equivalent case study indicated

  9. Computerized systems analysis and optimization of aircraft engine performance, weight, and life cycle costs

    NASA Technical Reports Server (NTRS)

    Fishbach, L. H.

    1979-01-01

    The computational techniques utilized to determine the optimum propulsion systems for future aircraft applications and to identify system tradeoffs and technology requirements are described. The characteristics and use of the following computer codes are discussed: (1) NNEP - a very general cycle analysis code that can assemble an arbitrary matrix fans, turbines, ducts, shafts, etc., into a complete gas turbine engine and compute on- and off-design thermodynamic performance; (2) WATE - a preliminary design procedure for calculating engine weight using the component characteristics determined by NNEP; (3) POD DRG - a table look-up program to calculate wave and friction drag of nacelles; (4) LIFCYC - a computer code developed to calculate life cycle costs of engines based on the output from WATE; and (5) INSTAL - a computer code developed to calculate installation effects, inlet performance and inlet weight. Examples are given to illustrate how these computer techniques can be applied to analyze and optimize propulsion system fuel consumption, weight, and cost for representative types of aircraft and missions.

  10. Environmental life cycle optimization of essential terpene oils produced by the macroalga Ochtodes secundiramea.

    PubMed

    Pérez-López, Paula; Jeffryes, Clayton; Agathos, Spiros N; Feijoo, Gumersindo; Rorrer, Gregory; Moreira, María Teresa

    2016-01-15

    The macroalga Ochtodes secundiramea is a well-known producer of essential terpene oils with promising biological activities and similar applications to those of microalgal biocompounds in the pharmaceutical, food or cosmetics sectors. This study assesses the environmental impacts associated with the production of five essential terpene oils (myrcene, 10Z-bromomyrcene, 10E-bromo-3-chloromyrcene, apakaochtodene B and acyclic C10H14Br2) by O. secundiramea cultivated in a closed airlift photobioreactor with artificial illumination. The results of the life cycle assessment (LCA) allowed analyzing the effect of implementing a semi-continuous operation on several stages of the life cycle of the products, which may lead to impact reductions from 1% up to 25%. Regarding the most problematic aspects of the process, the cultivation in the photobioreactor (S4) was identified as the main stage responsible for the environmental burdens, with contributions ranging between 60% and 80% of the total impacts for a semi-continuous production maintained during one year of operation. The electricity supply is the key activity affecting eight of the ten assessed categories and involves between 50% and 60% of the impact of the process. S4 is the main cause of the high energy requirements, with 86% of the total electricity consumption. Additionally, several scenarios aiming at improving the environmental profile of the system were evaluated. The application of LCA finally led to the proposal of two optimized scenarios with improvements between 8% and 40% with respect to the baseline case study.

  11. DFTr optimization and DFTr-MD studies of glucose, ten explicit water molecules enclosed by an implicit solvent, COSMO

    Technology Transfer Automated Retrieval System (TEKTRAN)

    DFTr optimization studies are carried out on alpha/beta-glucose surrounded by ten explicit water molecules and the glucose/water super-molecule completely enclosed by an implicit solvation model, COSMO. Twenty one starting configurations of the explicit waters were first optimized empirically with t...

  12. Integration and optimization of the gas removal system for hybrid-cycle OTEC power plants

    SciTech Connect

    Rabas, T.J.; Panchal, C.B.; Stevens, H.C. )

    1990-02-01

    A preliminary design of the noncondensible gas removal system for a 10 mWe, land-based hybrid-cycle OTEC power plant has been developed and is presented herein. This gas removal system is very different from that used for conventional power plants because of the substantially larger and continuous noncondensible gas flow rates and lower condenser pressure levels which predicate the need for higher-efficiency components. Previous OTEC studies discussed the need for multiple high-efficiency compressors with intercoolers; however, no previous design effort was devoted to the details of the intercoolers, integration and optimization of the intercoolers with the compressors, and the practical design constraints and feasibility issues of these components. The resulting gas removal system design uses centrifugal (radial) compressors with matrix-type crossflow aluminum heat exchangers as intercoolers. Once-through boiling of ammonia is used as the heat sink for the cooling and condensing of the steam-gas mixture. A computerized calculation method was developed for the performance analysis and subsystem optimization. For a specific number of compressor units and the stream arrangement, the method is used to calculate the dimensions, speeds, power requirements, and costs of all the components.

  13. Optimization and experimental validation of a thermal cycle that maximizes entropy coefficient fisher identifiability for lithium iron phosphate cells

    NASA Astrophysics Data System (ADS)

    Mendoza, Sergio; Rothenberger, Michael; Hake, Alison; Fathy, Hosam

    2016-03-01

    This article presents a framework for optimizing the thermal cycle to estimate a battery cell's entropy coefficient at 20% state of charge (SOC). Our goal is to maximize Fisher identifiability: a measure of the accuracy with which a parameter can be estimated. Existing protocols in the literature for estimating entropy coefficients demand excessive laboratory time. Identifiability optimization makes it possible to achieve comparable accuracy levels in a fraction of the time. This article demonstrates this result for a set of lithium iron phosphate (LFP) cells. We conduct a 24-h experiment to obtain benchmark measurements of their entropy coefficients. We optimize a thermal cycle to maximize parameter identifiability for these cells. This optimization proceeds with respect to the coefficients of a Fourier discretization of this thermal cycle. Finally, we compare the estimated parameters using (i) the benchmark test, (ii) the optimized protocol, and (iii) a 15-h test from the literature (by Forgez et al.). The results are encouraging for two reasons. First, they confirm the simulation-based prediction that the optimized experiment can produce accurate parameter estimates in 2 h, compared to 15-24. Second, the optimized experiment also estimates a thermal time constant representing the effects of thermal capacitance and convection heat transfer.

  14. Immobilization of Lipase by Adsorption Onto Magnetic Nanoparticles in Organic Solvents.

    PubMed

    Shi, Ying; Liu, Wei; Tao, Qing-Lan; Jiang, Xiao-Ping; Liu, Cai-Hong; Zeng, Sha; Zhang, Ye-Wang

    2016-01-01

    In order to improve the performance of lipase in organic solvents, a simple immobilization method was developed by adsorption of lipase onto Fe₃O₄@ SiO₂magnetic nanoparticles in organic solvent. Among the solvents tested, toluene was found to be the most effective solvent for the immobilization. A maximum immobilization yield of 97% and relative activity of 124% were achieved in toluene at 30 °C. The optimal temperature, enzyme loading and water activity were 30 °C, 1.25 mg/mg support and 0.48 aw, respectively. The residual activity of immobilized lipase was 67% after 10 cycles of use. The advantages of the immobilized lipase including easy recovery, high stability, and enhanced activity of immobilized lipase in organic solvents show potential industrial applications in anhydrous solvents.

  15. Solvent replacement for green processing.

    PubMed Central

    Sherman, J; Chin, B; Huibers, P D; Garcia-Valls, R; Hatton, T A

    1998-01-01

    The implementation of the Montreal Protocol, the Clean Air Act, and the Pollution Prevention Act of 1990 has resulted in increased awareness of organic solvent use in chemical processing. The advances made in the search to find "green" replacements for traditional solvents are reviewed, with reference to solvent alternatives for cleaning, coatings, and chemical reaction and separation processes. The development of solvent databases and computational methods that aid in the selection and/or design of feasible or optimal environmentally benign solvent alternatives for specific applications is also discussed. Images Figure 2 Figure 3 PMID:9539018

  16. Cuckoo Search Algorithm Based on Repeat-Cycle Asymptotic Self-Learning and Self-Evolving Disturbance for Function Optimization.

    PubMed

    Wang, Jie-sheng; Li, Shu-xia; Song, Jiang-di

    2015-01-01

    In order to improve convergence velocity and optimization accuracy of the cuckoo search (CS) algorithm for solving the function optimization problems, a new improved cuckoo search algorithm based on the repeat-cycle asymptotic self-learning and self-evolving disturbance (RC-SSCS) is proposed. A disturbance operation is added into the algorithm by constructing a disturbance factor to make a more careful and thorough search near the bird's nests location. In order to select a reasonable repeat-cycled disturbance number, a further study on the choice of disturbance times is made. Finally, six typical test functions are adopted to carry out simulation experiments, meanwhile, compare algorithms of this paper with two typical swarm intelligence algorithms particle swarm optimization (PSO) algorithm and artificial bee colony (ABC) algorithm. The results show that the improved cuckoo search algorithm has better convergence velocity and optimization accuracy.

  17. Optimal allocation and effectiveness of the heat exchangers for a power plant with two like-Carnot cycles

    NASA Astrophysics Data System (ADS)

    Aragón-González, G.; León-Galicia, A.

    2017-01-01

    A stationary power plant with two Carnot-like cycles is optimized. Each cycle has the following irreversibilities: finite rate heat transfer between the working fluid and the external heat sources, internal dissipation of the working fluid, and heat leak between reservoirs; is extended to two or more of this combined model. Using the Bellman’ Principle, we find the optimal recurrence relations for the allocation of the heat exchangers for this power plant. The optimal allocation or effectiveness of the heat exganchers of power plant is determined by two design rules: internal thermal conductance fixed; or areas fixed. The optimal obtained are invariant to the power and efficiency and to the heat transfer law.

  18. Optimized working conditions for a thermoelectric generator as a topping cycle for gas turbines

    NASA Astrophysics Data System (ADS)

    Brady Knowles, C.; Lee, Hohyun

    2012-10-01

    This paper presents a model for a theoretical maximum efficiency of a thermoelectric generator integrated with a Brayton-cycle engine. The thermoelectric cycle is presented in two configurations as a topping cycle and a preheating topping cycle. For the topping cycle configuration, the thermoelectric generator receives heat from a high-temperature heat source and produces electrical work before rejecting heat to a Brayton cycle. For the preheating topping cycle, the rejected heat from the thermoelectric generator partially heats the compressed working fluid of the Brayton cycle before a secondary heater delivers heat to the working fluid directly from the heat source. The thermoelectric topping cycle efficiency increases as the temperature difference between the hot- and cold-side increases; however, this limits the heat transfer possible to the Brayton cycle, which in turn reduces power generation from the Brayton cycle. This model identifies the optimum operating parameters of the thermoelectric and Brayton cycles to obtain the maximum thermal efficiency of the combined cycle. In both configurations, efficiency gains are larger at low-temperature Brayton cycles. Although a thermoelectric generator (TEG) topping cycle enhances efficiency for a low temperature turbine, efficiency cannot exceed a high temperature gas turbine. Using a TEG topping cycle is limited to cases when space or price for a high temperature turbine cannot be justified. A design to achieve the preheating thermoelectric topping cycle is also presented.

  19. Design of optimal solvent for extraction of bio–active ingredients from six varieties of Medicago sativa

    PubMed Central

    2012-01-01

    Background Extensive research has been performed worldwide and important evidences were collected to show the immense potential of plants used in various traditional therapeutic systems. The aim of this work is to investigate the different extracting solvents in terms of the influence of their polarity on the extracting ability of bioactive molecules (phenolic compounds) from the M. sativa flowers. Results The total phenolic content of samples was determined using the Folin Ciocalteu (FC) procedure and their antioxidant activity was assayed through in vitro radical decomposing activity using the radical DPPH° assay (IUPAC name for DPPH is (phenyl)–(2,4,6–trinitrophenyl) iminoazanium). The results showed that water was better than methanol and acetic acid for extracting bioactive compounds, in particular for total phenolic compounds from the flowers of alfalfa. The average content of bioactive molecules in methanol extract was 263.5±1.02 mg GAE/100g of dry weight lyophilized extract. The total phenolic content of the tested plant extracts was highly correlated with the radical decomposing activity. However, all extracts were free–radical inhibitors, but the water extract was more potent than the acetic and the methanol ones. The order of inhibitor effectiveness (expressed by IC50) proved to be: water extract (0.924mg/mL) > acetic acid extract (0.154mg/mL) > methanol (0.079mg/mL). The profiles of each extract (fingerprint) were characterized by FT–MIR spectroscopy. Conclusions The present study compares the fingerprint of different extracts of the M. sativa flowers, collected from the wild flora of Romania. The total phenolic content of the tested plant extracts was highly correlated with the radical decomposing activity. The dependence of the extract composition on the solvent polarity (acetic acid vs. methanol vs. water) was revealed by UV–VIS spectrometry and Infrared fingerprint. PMID:23098128

  20. Development of a protocol to optimize electric power consumption and life cycle environmental impacts for operation of wastewater treatment plant.

    PubMed

    Piao, Wenhua; Kim, Changwon; Cho, Sunja; Kim, Hyosoo; Kim, Minsoo; Kim, Yejin

    2016-12-01

    In wastewater treatment plants (WWTPs), the portion of operating costs related to electric power consumption is increasing. If the electric power consumption decreased, however, it would be difficult to comply with the effluent water quality requirements. A protocol was proposed to minimize the environmental impacts as well as to optimize the electric power consumption under the conditions needed to meet the effluent water quality standards in this study. This protocol was comprised of six phases of procedure and was tested using operating data from S-WWTP to prove its applicability. The 11 major operating variables were categorized into three groups using principal component analysis and K-mean cluster analysis. Life cycle assessment (LCA) was conducted for each group to deduce the optimal operating conditions for each operating state. Then, employing mathematical modeling, six improvement plans to reduce electric power consumption were deduced. The electric power consumptions for suggested plans were estimated using an artificial neural network. This was followed by a second round of LCA conducted on the plans. As a result, a set of optimized improvement plans were derived for each group that were able to optimize the electric power consumption and life cycle environmental impact, at the same time. Based on these test results, the WWTP operating management protocol presented in this study is deemed able to suggest optimal operating conditions under which power consumption can be optimized with minimal life cycle environmental impact, while allowing the plant to meet water quality requirements.

  1. Optimization and validation of a methodology based on solvent extraction and liquid chromatography for the simultaneous determination of several polyphenolic families in fruit juices.

    PubMed

    Abad-García, B; Berrueta, L A; López-Márquez, D M; Crespo-Ferrer, I; Gallo, B; Vicente, F

    2007-06-22

    A solvent extraction procedure of freeze-dried aliquots followed by the analysis of phenolic compounds by reversed-phase high-performance liquid chromatography (RP-HPLC) with photodiode array detection (DAD) has been developed for the analysis of polyphenolic compounds in fruit juices. This methodology is focussed on the characterization of fruit juices, mainly for quality control purposes. The effects of experimental variables, such as solvent composition and volume and time and temperature on extraction, have been studied. A unique gradient program for the separation of several phenolic classes (hydroquinones, hydroxybenzoic acids, flavan-3-oles, hydroxycinnamic acids, coumarins, flavanones, flavones, dihydrochalcones and flavonols) has been optimized, using standards of 55 commercially available phenolic compounds present in fruits, as well as representative real extracts from fruit juices. All phenolic compounds showed a high repeatability within-day (n=5) and between days (n=3) in peak area (RSD<8%) and excellent stability of their retention times. High precision was also observed in calibration slopes (RSD<8%). Detection limits ranged between 0.005 and 0.03 microg/mL for the different detected polyphenols. Complete recoveries (98-100%) were obtained for the majority of the phenolic structures of all representative phenolic families present in fruits. The method was successfully employed to measure diverse phenolic families in juices from 18 different fruits and consequently could be used for evaluate the quality of fruit juices.

  2. A global optimization method synthesizing heat transfer and thermodynamics for the power generation system with Brayton cycle

    NASA Astrophysics Data System (ADS)

    Fu, Rong-Huan; Zhang, Xing

    2016-09-01

    Supercritical carbon dioxide operated in a Brayton cycle offers a numerous of potential advantages for a power generation system, and a lot of thermodynamics analyses have been conducted to increase its efficiency. Because there are a lot of heat-absorbing and heat-lossing subprocesses in a practical thermodynamic cycle and they are implemented by heat exchangers, it will increase the gross efficiency of the whole power generation system to optimize the system combining thermodynamics and heat transfer theory. This paper analyzes the influence of the performance of heat exchangers on the actual efficiency of an ideal Brayton cycle with a simple configuration, and proposes a new method to optimize the power generation system, which aims at the minimum energy consumption. Although the method is operated only for the ideal working fluid in this paper, its merits compared to that only with thermodynamic analysis are fully shown.

  3. Life Cycle Assessment as a tool for water management optimization in textile finishing industry

    NASA Astrophysics Data System (ADS)

    Tarantini, Mario; Scalbi, Simona; Misceo, Monica; Verità, Simona

    2004-12-01

    In several countries, due to the increasing cost and shortage of water, textile finishing industries are looking for non conventional water resources. The use of reclaimed wastewater appears a technically feasible solution and is gaining a growing consensus. A European Union research project (TOWEF0, Towards effluent zero) with the aim of elaborating a multicriteria integrated and coherent methodology to support the implementation of sustainable water reuse in textile finishing processes has been recently concluded. In order to achieve an optimal compromise between minimization of environmental impacts of the production processes and maximum recovery of resources, Life Cycle Assessment (LCA) methodology has been applied to selected textile products manufactured within Belgian and Italian textile finishing companies. The study identified the key environmental issues within the finishing processes of a variety of natural (cotton, silk) and man-made (polyester, acetate, viscose) fibers and fabrics and analyzed alternative water reuse scenarios. Significant margins exist for impressive reductions in water consumption with almost no additional environmental impact adopting in situ membrane filtration technology. In this paper the methodological approach and the results of the LCA analyses applied to a flax-polyester product are presented and discussed.

  4. Solvent substitution

    SciTech Connect

    Not Available

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

  5. Cooperative effects of solvent and polymer acceptor co-additives in P3HT:PDI solar cells: simultaneous optimization in lateral and vertical phase separation.

    PubMed

    Li, Mingguang; Wang, Lei; Liu, Jiangang; Zhou, Ke; Yu, Xinhong; Xing, Rubo; Geng, Yanhou; Han, Yanchun

    2014-03-14

    In this work, solvent chloronaphthalene (CN) and polymer acceptor an alternating copolymer of perylene diimide and carbazole (PCPDI) were utilized as co-additives to optimize the nanoscale phase-separated morphology and photovoltaic properties of bulk-heterojunction (BHJ) polymer solar cells based on the poly(3-hexyl thiophene) (P3HT)/N,N'-bis(1-ethylpropyl)-perylene-3,4,9,10-tetracarboxylic diimide (EP-PDI) system. The domain size of EP-PDI molecules together with that of P3HT distinctly decreased by adding a 0.75 vol% CN additive. The optimized lateral phase separation increased the donor-acceptor interfacial area and facilitated the exciton dissociation process, leading to 5-fold enhancement of short-circuit current (JSC). Furthermore, when PCPDI was employed as a co-additive, acceptor materials (including PCPDI and EP-PDI) were prone to aggregation towards the top surface of blend films, improving vertical phase separation of active layers. PCPDI incorporation, which improved the percolation pathways for electron carriers, suppressed the crystallinity of P3HT distinctly. Thus, much more balanced charge transport was achieved by PCPDI addition, which resulted in almost 1-fold enhancement of open-circuit voltage (VOC) by reducing nongeminate recombination. As a consequence, cooperative effects of CN and PCPDI additives improved the nanoscale phase-separated morphology in lateral and vertical directions simultaneously, achieving the enhancement in both VOC and JSC.

  6. Unraveling the fundamental mechanisms of solvent-additive-induced optimization of power conversion efficiencies in organic photovoltaic devices

    SciTech Connect

    Herath, Nuradhika; Das, Sanjib; Zhu, Jiahua; Kumar, Rajeev; Chen, Jihua; Xiao, Kai; Gu, Gong; Browning, James F.; Sumpter, Bobby G.; Ivanov, Ilia N.; Lauter, Valeria

    2016-07-12

    The realization of controllable morphologies of bulk heterojunction (BHJ) in organic photovoltics (OPVs) is one of the key factors in obtaining high-efficiency devices. Here via simultaneous monitoring of the three-dimensional nanostructural modifications in BHJ correlated with the optical analysis and theoretical modeling of charge transport, we provide new insights into the fundamental mechanisms essential for the optimization of (power conversion efficiency) PCEs with additive processing. Our results demonstrate how a trace amount of diiodooctane (DIO) remarkably changes the vertical phase morphology of the active layers resulting in formation of a well-mixed donor-acceptor compact film, augments charge transfer and PCEs. In contrast, excess amount of DIO promotes a massive reordering and results loosely packed mixed phase vertical phase morphology with large clusters leading to deterioration in PCEs. Theoretical modeling of charge transport reveals that DIO increases the mobility of electrons and holes (the charge carriers) by affecting the energetic disorder and electric field dependence of the mobility. Our results show the significant of phase separation and carrier transport pathways to achieve optimal device performances.

  7. Unraveling the fundamental mechanisms of solvent-additive-induced optimization of power conversion efficiencies in organic photovoltaic devices

    DOE PAGES

    Herath, Nuradhika; Das, Sanjib; Zhu, Jiahua; ...

    2016-07-12

    The realization of controllable morphologies of bulk heterojunction (BHJ) in organic photovoltics (OPVs) is one of the key factors in obtaining high-efficiency devices. Here via simultaneous monitoring of the three-dimensional nanostructural modifications in BHJ correlated with the optical analysis and theoretical modeling of charge transport, we provide new insights into the fundamental mechanisms essential for the optimization of (power conversion efficiency) PCEs with additive processing. Our results demonstrate how a trace amount of diiodooctane (DIO) remarkably changes the vertical phase morphology of the active layers resulting in formation of a well-mixed donor-acceptor compact film, augments charge transfer and PCEs. Inmore » contrast, excess amount of DIO promotes a massive reordering and results loosely packed mixed phase vertical phase morphology with large clusters leading to deterioration in PCEs. Theoretical modeling of charge transport reveals that DIO increases the mobility of electrons and holes (the charge carriers) by affecting the energetic disorder and electric field dependence of the mobility. Our results show the significant of phase separation and carrier transport pathways to achieve optimal device performances.« less

  8. Rapid freeze-drying cycle optimization using computer programs developed based on heat and mass transfer models and facilitated by tunable diode laser absorption spectroscopy (TDLAS).

    PubMed

    Kuu, Wei Y; Nail, Steven L

    2009-09-01

    Computer programs in FORTRAN were developed to rapidly determine the optimal shelf temperature, T(f), and chamber pressure, P(c), to achieve the shortest primary drying time. The constraint for the optimization is to ensure that the product temperature profile, T(b), is below the target temperature, T(target). Five percent mannitol was chosen as the model formulation. After obtaining the optimal sets of T(f) and P(c), each cycle was assigned with a cycle rank number in terms of the length of drying time. Further optimization was achieved by dividing the drying time into a series of ramping steps for T(f), in a cascading manner (termed the cascading T(f) cycle), to further shorten the cycle time. For the purpose of demonstrating the validity of the optimized T(f) and P(c), four cycles with different predicted lengths of drying time, along with the cascading T(f) cycle, were chosen for experimental cycle runs. Tunable diode laser absorption spectroscopy (TDLAS) was used to continuously measure the sublimation rate. As predicted, maximum product temperatures were controlled slightly below the target temperature of -25 degrees C, and the cascading T(f)-ramping cycle is the most efficient cycle design. In addition, the experimental cycle rank order closely matches with that determined by modeling.

  9. Maximum equivalent power output and performance optimization analysis of an alkaline fuel cell/heat-driven cycle hybrid system

    NASA Astrophysics Data System (ADS)

    Zhang, Xiuqin; Chen, Jincan

    A generic model of the hybrid system consisting of an alkaline fuel cell (AFC) and a heat-driven cycle, which may work as either a refrigerator or a heat pump, is originally established. On the basis of the models of AFCs and three-heat-reservoir cycles, the equivalent power output and efficiency of the hybrid system are obtained. The performance characteristic curves of the hybrid system are represented through numerical calculation. The maximum equivalent power output and efficiency of the hybrid system are determined. Problems concerning the optimal operation of the hybrid system are discussed. The effects of the main irreversible losses on the performance of the hybrid system are investigated in detail. It is important to note that the waste heat produced in the AFC can be readily used in such a hybrid cycle.

  10. Performance assessment and optimization of an irreversible nano-scale Stirling engine cycle operating with Maxwell-Boltzmann gas

    NASA Astrophysics Data System (ADS)

    Ahmadi, Mohammad H.; Ahmadi, Mohammad-Ali; Pourfayaz, Fathollah

    2015-09-01

    Developing new technologies like nano-technology improves the performance of the energy industries. Consequently, emerging new groups of thermal cycles in nano-scale can revolutionize the energy systems' future. This paper presents a thermo-dynamical study of a nano-scale irreversible Stirling engine cycle with the aim of optimizing the performance of the Stirling engine cycle. In the Stirling engine cycle the working fluid is an Ideal Maxwell-Boltzmann gas. Moreover, two different strategies are proposed for a multi-objective optimization issue, and the outcomes of each strategy are evaluated separately. The first strategy is proposed to maximize the ecological coefficient of performance (ECOP), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F . Furthermore, the second strategy is suggested to maximize the thermal efficiency ( η), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F). All the strategies in the present work are executed via a multi-objective evolutionary algorithms based on NSGA∥ method. Finally, to achieve the final answer in each strategy, three well-known decision makers are executed. Lastly, deviations of the outcomes gained in each strategy and each decision maker are evaluated separately.

  11. Optimization of a green extraction method for the recovery of polyphenols from olive leaf using cyclodextrins and glycerin as co-solvents.

    PubMed

    Mourtzinos, Ioannis; Anastasopoulou, Eleni; Petrou, Athanasios; Grigorakis, Spyros; Makris, Dimitris; Biliaderis, Costas G

    2016-11-01

    Olive leaf, an agricultural by-product, was studied for the valorization of its biophenols using green extraction techniques; i.e. non-toxic and eco-friendly extraction solvents were used, involving water and glycerol. 2-hydroxypropyl-β-cyclodextrin (CD), was also employed as an enhancer of the extraction, since cyclodextrins (CD's) are known to improve the extractability of olive leaf polyphenols by forming water soluble inclusion complexes. The process was optimized by implementing a central composite (Box-Behnken) experimental design and response surface methodology, taking into consideration the following independent variables: glycerol concentration (Cgl), CD concentration (CCD) and temperature (T). The evaluation of the extraction model was based on two responses: the total polyphenol yield (YTP) and the antiradical activity (AAR). Optimum values for the extraction process were obtained at 60% (w/v) glycerol content, T = 60 °C and 7% (w/v) CD content. LC-MS analysis was also applied in order to characterize the polyphenolic composition of extracts containing cyclodextrins. The main polyphenols present were oleuropein and oleuropein derivatives. Olive leaf aqueous extracts containing glycerol and cyclodextrins may be used as raw materials/ingredients for several end-users in the food, cosmetic and pharmaceutical industries.

  12. CHALLENGES AND OPPORTUNITIES--INTEGRATED LIFE-CYCLE OPTIMIZATION INITIATIVES FOR THE HANFORD RIVER PROTECTION PROJECT--WASTE TREATMENT PLANT

    SciTech Connect

    Auclair, K. D.

    2002-02-25

    This paper describes the ongoing integrated life-cycle optimization efforts to achieve both design flexibility and design stability for activities associated with the Waste Treatment Plant at Hanford. Design flexibility is required to support the Department of Energy Office of River Protection Balance of Mission objectives, and design stability to meet the Waste Treatment Plant construction and commissioning requirements in order to produce first glass in 2007. The Waste Treatment Plant is a large complex project that is driven by both technology and contractual requirements. It is also part of a larger overall mission, as a component of the River Protection Project, which is driven by programmatic requirements and regulatory, legal, and fiscal constraints. These issues are further complicated by the fact that both of the major contractors involved have a different contract type with DOE, and neither has a contract with the other. This combination of technical and programmatic drivers, constraints, and requirements will continue to provide challenges and opportunities for improvement and optimization. The Bechtel National, Inc. team is under contract to engineer, procure, construct, commission and test the Waste Treatment Plant on or ahead of schedule, at or under cost, and with a throughput capacity equal to or better than specified. The Department of Energy is tasked with the long term mission of waste retrieval, treatment, and disposal. While each mission is a compliment and inextricably linked to one another, they are also at opposite ends of the spectrum, in terms of expectations of one another. These mission requirements, that are seemingly in opposition to one another, pose the single largest challenge and opportunity for optimization: one of balance. While it is recognized that design maturation and optimization are the normal responsibility of any engineering firm responsible for any given project, the aspects of integrating requirements and the management

  13. Entransy analysis and optimization of performance of nano-scale irreversible Otto cycle operating with Maxwell-Boltzmann ideal gas

    NASA Astrophysics Data System (ADS)

    Ahmadi, Mohammad H.; Ahmadi, Mohammad Ali; Pourfayaz, Fathollah; Bidi, Mokhtar

    2016-08-01

    This paper made attempt to investigate thermodynamically a nano scale irreversible Otto cycle for optimizing its performance. This system employed an ideal Maxwell-Boltzmann gas as a working fluid. Two different scenarios were proposed in the multi-objective optimization process and the results of each of the scenarios were examined separately. The first scenario made attempt to maximize the dimensionless ecological function and minimize the dimensionless entransy dissipation of the system. Furthermore, the second scenario tried to maximize the ecological coefficient of performance and minimize the dimensionless entransy dissipation of the system. The multi objective evolutionary method integrated with non-dominated sorting genetic algorithm was used to optimize the proposed objective functions. To determine the final output of each scenario, three efficient decision makers were employed. Finally, error analysis was employed to determine the deviation of solutions chosen by decision makers.

  14. The effect of noise constraints on engine cycle optimization for long-haul transports

    NASA Technical Reports Server (NTRS)

    Antl, R. J.

    1973-01-01

    Results are presented of NASA studies to determine optimum engine cycles for noise levels of 10, 15, and 20 EPNdb below current FAA regulations. The study aircraft were 200-passenger trijets flying over ranges of 5,556 and 10,200 km at cruise speeds of Mach 0.90 to 0.98. The economic impact of reducing noise, the identification of needed advanced technology and the effect of these advances are presented. The studies showed that the noise constraints imposed compromises on the optimum cycle with resulting economic penalties. The application of advanced engine technologies, however, could effectively offset these economic penalties.

  15. Optimizing the Wingate Anaerobic Cycling Test for youth with juvenile idiopathic arthritis.

    PubMed

    Obeid, Joyce; Larché, Maggie J; Timmons, Brian W

    2011-08-01

    The Wingate Anaerobic Test (WAnT) can assess muscle function in youth with juvenile idiopathic arthritis (JIA). Our objective was to compare peak power (PP) and mean power (MP) when the WAnT is performed with a standard vs. an optimized braking force. Eight patients with JIA between the ages of 8 and 18 participated in two sessions. Optimal braking force was determined with a series of 15-s force-velocity tests performed against braking forces ranging from 3.5 to 8.5% of body weight. Participants then performed two randomized WAnTs against the standard (4.5%) and optimal braking forces. PP tended to be greater in the optimized vs. standard WAnT (12.5 ± 2.6 vs. 10.8 ± 1.0 W/kg, respectively; p = .07). No differences were observed for MP (standard: 6.2 ± 0.9 vs. optimized: 6.2 ± 1.1 W/kg; p = .9). Optimization of the WAnT tended to increase PP by 10-28% in youth with JIA.

  16. Optimal synthesis and design of the number of cycles in the leaching process for surimi production.

    PubMed

    Reinheimer, M Agustina; Scenna, Nicolás J; Mussati, Sergio F

    2016-12-01

    Water consumption required during the leaching stage in the surimi manufacturing process strongly depends on the design and the number and size of stages connected in series for the soluble protein extraction target, and it is considered as the main contributor to the operating costs. Therefore, the optimal synthesis and design of the leaching stage is essential to minimize the total annual cost. In this study, a mathematical optimization model for the optimal design of the leaching operation is presented. Precisely, a detailed Mixed Integer Nonlinear Programming (MINLP) model including operating and geometric constraints was developed based on our previous optimization model (NLP model). Aspects about quality, water consumption and main operating parameters were considered. The minimization of total annual costs, which considered a trade-off between investment and operating costs, led to an optimal solution with lesser number of stages (2 instead of 3 stages) and higher volumes of the leaching tanks comparing with previous results. An analysis was performed in order to investigate how the optimal solution was influenced by the variations of the unitary cost of fresh water, waste treatment and capital investment.

  17. Method of optimizing performance of Rankine cycle power plants. [US DOE Patent

    DOEpatents

    Pope, W.L.; Pines, H.S.; Doyle, P.A.; Silvester, L.F.

    1980-06-23

    A method is described for efficiently operating a Rankine cycle power plant to maximize fuel utilization efficiency or energy conversion efficiency or minimize costs by selecting a turbine fluid inlet state which is substantially on the area adjacent and including the transposed critical temperature line.

  18. Efficiency enhancement for natural gas liquefaction with CO2 capture and sequestration through cycles innovation and process optimization

    NASA Astrophysics Data System (ADS)

    Alabdulkarem, Abdullah

    Liquefied natural gas (LNG) plants are energy intensive. As a result, the power plants operating these LNG plants emit high amounts of CO2 . To mitigate global warming that is caused by the increase in atmospheric CO2, CO2 capture and sequestration (CCS) using amine absorption is proposed. However, the major challenge of implementing this CCS system is the associated power requirement, increasing power consumption by about 15--25%. Therefore, the main scope of this work is to tackle this challenge by minimizing CCS power consumption as well as that of the entire LNG plant though system integration and rigorous optimization. The power consumption of the LNG plant was reduced through improving the process of liquefaction itself. In this work, a genetic algorithm (GA) was used to optimize a propane pre-cooled mixed-refrigerant (C3-MR) LNG plant modeled using HYSYS software. An optimization platform coupling Matlab with HYSYS was developed. New refrigerant mixtures were found, with savings in power consumption as high as 13%. LNG plants optimization with variable natural gas feed compositions was addressed and the solution was proposed through applying robust optimization techniques, resulting in a robust refrigerant which can liquefy a range of natural gas feeds. The second approach for reducing the power consumption is through process integration and waste heat utilization in the integrated CCS system. Four waste heat sources and six potential uses were uncovered and evaluated using HYSYS software. The developed models were verified against experimental data from the literature with good agreement. Net available power enhancement in one of the proposed CCS configuration is 16% more than the conventional CCS configuration. To reduce the CO2 pressurization power into a well for enhanced oil recovery (EOR) applications, five CO2 pressurization methods were explored. New CO2 liquefaction cycles were developed and modeled using HYSYS software. One of the developed

  19. Aminosilicone solvents for CO(2) capture.

    PubMed

    Perry, Robert J; Grocela-Rocha, Teresa A; O'Brien, Michael J; Genovese, Sarah; Wood, Benjamin R; Lewis, Larry N; Lam, Hubert; Soloveichik, Grigorii; Rubinsztajn, Malgorzata; Kniajanski, Sergei; Draper, Sam; Enick, Robert M; Johnson, J Karl; Xie, Hong-bin; Tapriyal, Deepak

    2010-08-23

    This work describes the first report of the use of an aminosilicone solvent mix for the capture of CO(2). To maintain a liquid state, a hydroxyether co-solvent was employed which allowed enhanced physisorption of CO(2) in the solvent mixture. Regeneration of the capture solvent system was demonstrated over 6 cycles and absorption isotherms indicate a 25-50 % increase in dynamic CO(2) capacity over 30 % MEA. In addition, proof of concept for continuous CO(2) absorption was verified. Additionally, modeling to predict heats of reaction of aminosilicone solvents with CO(2) was in good agreement with experimental results.

  20. Cyst and encystment in protozoan parasites: optimal targets for new life-cycle interrupting strategies?

    PubMed

    Aguilar-Díaz, Hugo; Carrero, Julio César; Argüello-García, Raúl; Laclette, Juan Pedro; Morales-Montor, Jorge

    2011-10-01

    Certain protozoan parasites use survival strategies to reside outside the host such as the formation of cysts. This dormant and resistant stage results from the complex process of encystment that involves diverse molecular and cellular modifications. The stimuli and changes associated with cyst biogenesis are a matter of ongoing studies in human and animal protozoan parasites such as amoeba and Giardia species because blocking every step in the encystment pathway should, in theory, interrupt their life cycles. The present review thoroughly examines this essential process in those protozoan parasites and discusses the possibility of using that information to develop new kinds of anti-parasite specific and life cycle-interrupting drugs, aimed at holding back the dissemination of these infections.

  1. Optimization of the thermodynamic cycles of a collective heating power station

    NASA Astrophysics Data System (ADS)

    Hausmann, G.

    The optimization of the centralized heating system of a city was studied. Modifications of the heating circuit increase the electric power characteristic from 0.20 to 0.37. A program for the calculation of the changes in the thermodynamic cyclic due to these modifications is presented.

  2. Optimization of phosphatase- and redox cycling-based immunosensors and its application to ultrasensitive detection of troponin I.

    PubMed

    Akanda, Md Rajibul; Aziz, Md Abdul; Jo, Kyungmin; Tamilavan, Vellaiappillai; Hyun, Myung Ho; Kim, Sinyoung; Yang, Haesik

    2011-05-15

    The authors herein report optimized conditions for ultrasensitive phosphatase-based immunosensors (using redox cycling by a reducing agent) that can be simply prepared and readily applied to microfabricated electrodes. The optimized conditions were applied to the ultrasensitive detection of cardiac troponin I in human serum. The preparation of an immunosensing layer was based on passive adsorption of avidin (in carbonate buffer (pH 9.6)) onto indium-tin oxide (ITO) electrodes. The immunosensing layer allows very low levels of nonspecific binding of proteins. The optimum conditions for the enzymatic reaction were investigated in terms of the type of buffer solution, temperature, and concentration of MgCl(2), and the optimum conditions for antigen-antibody binding were determined in terms of incubation time, temperature, and concentration of phosphatase-conjugated IgG. Very importantly, the antigen-antibody binding at 4 °C is extremely important in obtaining reproducible results. Among the four phosphatase substrates (L-ascorbic acid 2-phosphate (AAP), 4-aminophenyl phosphate, 1-naphthyl phosphate, 4-amino-1-naphthyl phosphate) and four phosphatase products (L-ascorbic acid (AA), 4-aminophenol, 1-naphthol, 4-amino-1-naphthol), AAP and AA meet the requirements most for obtaining easy dissolution and high signal-to-background ratios. More importantly, fast AA electrooxidation at the ITO electrodes does not require modification with any electrocatalyst or electron mediator. Furthermore, tris(2-carboxyethyl)phosphine (TCEP) as a reducing agent allows fast redox cycling, along with very low anodic currents at the ITO electrodes. Under these optimized conditions, the detection limit of an immunosensor for troponin I obtained without redox cycling of AA by TCEP is ca. 100 fg/mL, and with redox cycling it is ca. 10 fg/mL. A detection limit of 10 fg/mL was also obtained even when an immunosensing layer was simply formed on a micropatterned ITO electrode. From a practical

  3. Optimization of an accelerated solvent extraction dispersive liquid-liquid microextraction method for the separation and determination of essential oil from Ligusticum chuanxiong Hort by gas chromatography with mass spectrometry.

    PubMed

    Yang, Guang; Sun, Qiushi; Hu, Zhiyan; Liu, Hua; Zhou, Tingting; Fan, Guorong

    2015-10-01

    In this study, an accelerated solvent extraction dispersive liquid-liquid microextraction coupled with gas chromatography and mass spectrometry was established and employed for the extraction, concentration and analysis of essential oil constituents from Ligusticum chuanxiong Hort. Response surface methodology was performed to optimize the key parameters in accelerated solvent extraction on the extraction efficiency, and key parameters in dispersive liquid-liquid microextraction were discussed as well. Two representative constituents in Ligusticum chuanxiong Hort, (Z)-ligustilide and n-butylphthalide, were quantitatively analyzed. It was shown that the qualitative result of the accelerated solvent extraction dispersive liquid-liquid microextraction approach was in good agreement with that of hydro-distillation, whereas the proposed approach took far less extraction time (30 min), consumed less plant material (usually <1 g, 0.01 g for this study) and solvent (<20 mL) than the conventional system. To sum up, the proposed method could be recommended as a new approach in the extraction and analysis of essential oil.

  4. Development and optimization of a naphthoic acid-based ionic liquid as a "non-organic solvent microextraction" for the determination of tetracycline antibiotics in milk and chicken eggs.

    PubMed

    Gao, Jiajia; Wang, Hui; Qu, Jingang; Wang, Huili; Wang, Xuedong

    2017-01-15

    In traditional ionic liquids (ILs)-based microextraction, ILs are often used as extraction and dispersive solvents; however, their functional effects are not fully utilized. Herein, we developed a novel ionic liquid 1-butyl-3-methylimidazolium naphthoic acid salt ([C4MIM][NPA]) with strong acidity. It was used as a mixed dispersive solvent with conventional [C2MIM][BF4] in "functionalized ionic liquid-based non-organic solvent microextraction (FIL-NOSM)" for determination of tetracycline antibiotics (TCs) in milk and eggs. Utilization of [C4MIM][NPA] in FIL-NOSM method increased extraction recoveries (ERs) of TCs by more than 20% and eliminated the pH adjustment step because of its strong acidity. Under optimized conditions based on central composite design, the ERs of four TCs were 94.1-102.1%, and the limitsofdetection were 0.08-1.12μgkg(-1) in milk and egg samples. This proposed method provides high extraction efficiency, less pretreatment time and requires non-organic solvents for determination of trace TC concentrations in complex animal-based food matrices.

  5. Optimized Stem Cell Detection Using the DyeCycle-Triggered Side Population Phenotype.

    PubMed

    Boesch, Maximilian; Wolf, Dominik; Sopper, Sieghart

    2016-01-01

    Tissue and cancer stem cells are highly attractive target populations for regenerative medicine and novel potentially curative anticancer therapeutics. In order to get a better understanding of stem cell biology and function, it is essential to reproducibly identify these stem cells from biological samples for subsequent characterization or isolation. ABC drug transporter expression is a hallmark of stem cells. This is utilized to identify (cancer) stem cells by exploiting their dye extrusion properties, which is referred to as the "side population assay." Initially described for high-end flow cytometers equipped with ultraviolet lasers, this technique is now also amenable for a broader scientific community, owing to the increasing availability of violet laser-furnished cytometers and the advent of DyeCycle Violet (DCV). Here, we describe important technical aspects of the DCV-based side population assay and discuss potential pitfalls and caveats helping scientists to establish a valid and reproducible DCV-based side population assay. In addition, we investigate the suitability of blue laser-excitable DyeCycle dyes for side population detection. This knowledge will help to improve and standardize detection and isolation of stem cells based on their expression of ABC drug transporters.

  6. Solvent degradation products in nuclear fuel processing solvents

    SciTech Connect

    Shook, H.E. Jr.

    1988-06-01

    The Savannah River Plant uses a modified Purex process to recover enriched uranium and separate fission products. This process uses 7.5% tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons for the solvent extraction of a nitric acid solution containing the materials to be separated. Periodic problems in product decontamination result from solvent degradation. A study to improve process efficiency has identified certain solvent degradation products and suggested mitigation measures. Undecanoic acid, lauric acid, and tridecanoic acid were tentatively identified as diluent degradation products in recycle solvent. These long-chain organic acids affect phase separation and lead to low decontamination factors. Solid phase extraction (SPE) was used to concentrate the organic acids in solvent prior to analysis by high performance liquid chromatography (HPLC). SPE and HPLC methods were optimized in this work for analysis of decanoic acid, undecanoic acid, and lauric acid in solvent. Accelerated solvent degradation studies with 7.5% TBP in normal paraffin hydrocarbons showed that long-chain organic acids and long-chain alkyl butyl phosphoric acids are formed by reactions with nitric acid. Degradation of both tributyl phosphate and hydrocarbon can be minimized with purified normal paraffin replacing the standard grade presently used. 12 refs., 1 fig., 3 tabs.

  7. Optimization of the oxidant supply system for combined cycle MHD power plants

    NASA Technical Reports Server (NTRS)

    Juhasz, A. J.

    1982-01-01

    An in-depth study was conducted to determine what, if any, improvements could be made on the oxidant supply system for combined cycle MHD power plants which could be reflected in higher thermal efficiency and a reduction in the cost of electricity, COE. A systematic analysis of air separation process varitions which showed that the specific energy consumption could be minimized when the product stream oxygen concentration is about 70 mole percent was conducted. The use of advanced air compressors, having variable speed and guide vane position control, results in additional power savings. The study also led to the conceptual design of a new air separation process, sized for a 500 MW sub e MHD plant, referred to a internal compression is discussed. In addition to its lower overall energy consumption, potential capital cost savings were identified for air separation plants using this process when constructed in a single large air separation train rather than multiple parallel trains, typical of conventional practice.

  8. Computerized systems analysis and optimization of aircraft engine performance, weight, and life cycle costs

    NASA Technical Reports Server (NTRS)

    Fishbach, L. H.

    1979-01-01

    The paper describes the computational techniques employed in determining the optimal propulsion systems for future aircraft applications and to identify system tradeoffs and technology requirements. The computer programs used to perform calculations for all the factors that enter into the selection process of determining the optimum combinations of airplanes and engines are examined. Attention is given to the description of the computer codes including NNEP, WATE, LIFCYC, INSTAL, and POD DRG. A process is illustrated by which turbine engines can be evaluated as to fuel consumption, engine weight, cost and installation effects. Examples are shown as to the benefits of variable geometry and of the tradeoff between fuel burned and engine weights. Future plans for further improvements in the analytical modeling of engine systems are also described.

  9. In-situ transesterification of seeds of invasive Chinese tallow trees (Triadica sebifera L.) in a microwave batch system (GREEN(3)) using hexane as co-solvent: Biodiesel production and process optimization.

    PubMed

    Barekati-Goudarzi, Mohamad; Boldor, Dorin; Nde, Divine B

    2016-02-01

    In-situ transesterification (simultaneous extraction and transesterification) of Chinese tallow tree seeds into methyl esters using a batch microwave system was investigated in this study. A high degree of oil extraction and efficient conversion of oil to biodiesel were found in the proposed range. The process was further optimized in terms of product yields and conversion rates using Doehlert optimization methodology. Based on the experimental results and statistical analysis, the optimal production yield conditions for this process were determined as: catalyst concentration of 1.74wt.%, solvent ratio about 3 (v/w), reaction time of 20min and temperature of 58.1°C. H(+)NMR was used to calculate reaction conversion. All methyl esters produced using this method met ASTM biodiesel quality specifications.

  10. Novel pathways for fuels and lubricants from biomass optimized using life-cycle greenhouse gas assessment.

    PubMed

    Balakrishnan, Madhesan; Sacia, Eric R; Sreekumar, Sanil; Gunbas, Gorkem; Gokhale, Amit A; Scown, Corinne D; Toste, F Dean; Bell, Alexis T

    2015-06-23

    Decarbonizing the transportation sector is critical to achieving global climate change mitigation. Although biofuels will play an important role in conventional gasoline and diesel applications, bioderived solutions are particularly important in jet fuels and lubricants, for which no other viable renewable alternatives exist. Producing compounds for jet fuel and lubricant base oil applications often requires upgrading fermentation products, such as alcohols and ketones, to reach the appropriate molecular-weight range. Ketones possess both electrophilic and nucleophilic functionality, which allows them to be used as building blocks similar to alkenes and aromatics in a petroleum refining complex. Here, we develop a method for selectively upgrading biomass-derived alkyl methyl ketones with >95% yields into trimer condensates, which can then be hydrodeoxygenated in near-quantitative yields to give a new class of cycloalkane compounds. The basic chemistry developed here can be tailored for aviation fuels as well as lubricants by changing the production strategy. We also demonstrate that a sugarcane biorefinery could use natural synergies between various routes to produce a mixture of lubricant base oils and jet fuels that achieve net life-cycle greenhouse gas savings of up to 80%.

  11. Optimized, Competitive Supercritical-CO2 Cycle GFR for Gen IV Service

    SciTech Connect

    M.J. Driscoll; P. Hejzlar; G. Apostolakis

    2008-09-08

    An overall plant design was developed for a gas-cooled fast reactor employing a direct supercritical Brayton power conversion system. The most important findings were that (1) the concept could be capital-cost competitive, but startup fuel cycle costs are penalized by the low core power density, specified in large part to satisfy the goal of significatn post-accident passive natural convection cooling; (2) active decay heat removal is preferable as the first line of defense, with passive performance in a backup role; (3) an innovative tube-in-duct fuel assembly, vented to the primpary coolant, appears to be practicable; and (4) use of the S-Co2 GFR to support hydrogen production is a synergistic application, since sufficient energy can be recuperated from the product H2 and 02 to allow the electrolysis cell to run 250 C hotter than the reactor coolant, and the water boilers can be used for reactor decay heat removal. Increasing core poer density is identified as the top priority for future work on GFRs of this type.

  12. Novel pathways for fuels and lubricants from biomass optimized using life-cycle greenhouse gas assessment

    DOE PAGES

    Balakrishnan, Madhesan; Sacia, Eric R.; Sreekumar, Sanil; ...

    2015-06-08

    Decarbonizing the transportation sector is critical to achieving global climate change mitigation. Although biofuels will play an important role in conventional gasoline and diesel applications, bioderived solutions are particularly important in jet fuels and lubricants, for which no other viable renewable alternatives exist. Producing compounds for jet fuel and lubricant base oil applications often requires upgrading fermentation products, such as alcohols and ketones, to reach the appropriate molecular-weight range. Ketones possess both electrophilic and nucleophilic functionality, which allows them to be used as building blocks similar to alkenes and aromatics in a petroleum refining complex. Here, we develop a methodmore » for selectively upgrading biomass-derived alkyl methyl ketones with >95% yields into trimer condensates, which can then be hydrodeoxygenated in near-quantitative yields to give a new class of cycloalkane compounds. The basic chemistry developed here can be tailored for aviation fuels as well as lubricants by changing the production strategy. We demonstrate that a sugarcane biorefinery could use natural synergies between various routes to produce a mixture of lubricant base oils and jet fuels that achieve net life-cycle greenhouse gas savings of up to 80%.« less

  13. Novel pathways for fuels and lubricants from biomass optimized using life-cycle greenhouse gas assessment

    SciTech Connect

    Balakrishnan, Madhesan; Sacia, Eric R.; Sreekumar, Sanil; Gunbas, Gorkem; Gokhale, Amit A.; Scown, Corinne D.; Toste, F. Dean; Bell, Alexis T.

    2015-06-08

    Decarbonizing the transportation sector is critical to achieving global climate change mitigation. Although biofuels will play an important role in conventional gasoline and diesel applications, bioderived solutions are particularly important in jet fuels and lubricants, for which no other viable renewable alternatives exist. Producing compounds for jet fuel and lubricant base oil applications often requires upgrading fermentation products, such as alcohols and ketones, to reach the appropriate molecular-weight range. Ketones possess both electrophilic and nucleophilic functionality, which allows them to be used as building blocks similar to alkenes and aromatics in a petroleum refining complex. Here, we develop a method for selectively upgrading biomass-derived alkyl methyl ketones with >95% yields into trimer condensates, which can then be hydrodeoxygenated in near-quantitative yields to give a new class of cycloalkane compounds. The basic chemistry developed here can be tailored for aviation fuels as well as lubricants by changing the production strategy. We demonstrate that a sugarcane biorefinery could use natural synergies between various routes to produce a mixture of lubricant base oils and jet fuels that achieve net life-cycle greenhouse gas savings of up to 80%.

  14. Novel pathways for fuels and lubricants from biomass optimized using life-cycle greenhouse gas assessment

    PubMed Central

    Balakrishnan, Madhesan; Sacia, Eric R.; Sreekumar, Sanil; Gunbas, Gorkem; Gokhale, Amit A.; Scown, Corinne D.; Toste, F. Dean; Bell, Alexis T.

    2015-01-01

    Decarbonizing the transportation sector is critical to achieving global climate change mitigation. Although biofuels will play an important role in conventional gasoline and diesel applications, bioderived solutions are particularly important in jet fuels and lubricants, for which no other viable renewable alternatives exist. Producing compounds for jet fuel and lubricant base oil applications often requires upgrading fermentation products, such as alcohols and ketones, to reach the appropriate molecular-weight range. Ketones possess both electrophilic and nucleophilic functionality, which allows them to be used as building blocks similar to alkenes and aromatics in a petroleum refining complex. Here, we develop a method for selectively upgrading biomass-derived alkyl methyl ketones with >95% yields into trimer condensates, which can then be hydrodeoxygenated in near-quantitative yields to give a new class of cycloalkane compounds. The basic chemistry developed here can be tailored for aviation fuels as well as lubricants by changing the production strategy. We also demonstrate that a sugarcane biorefinery could use natural synergies between various routes to produce a mixture of lubricant base oils and jet fuels that achieve net life-cycle greenhouse gas savings of up to 80%. PMID:26056307

  15. Optimization of the catalytic oxidation of CO for closed-cycle CO2 laser applications

    NASA Technical Reports Server (NTRS)

    Miller, I. M.; Wood, G. M.; Schryer, D. R.; Hess, R. V.; Upchurch, B. T.; Brown, K. G.; Sidney, B. D.

    1985-01-01

    This report develops a basis for the design of a catalyst bed for the recombination of CO and O2 in a closed-cycle CO2 laser system. The catalyst is 1% Pt on SnO2 having a BET surface area of 6.7 sq m/g and a specific void volume of 0.374 cu cm/g. The design conditions are: a catalyst bed temperature of 100 C and a circulating flow rate of 10 lambda/min. Under these conditions, the required quantity of catalyst for prolonged laser operation of 668g. The rat law for the reaction of a stoichiometric mixture of 1% CO + 1/2% O2 in helium was determined to be overall first order; however, additional experiments with non-stoichiometric gas mixtures of CO and O2 are needed to determine the order of the CO concentration and the order of the O2 concentration in the rate law.

  16. Identifying energy and carbon footprint optimization potentials of a sludge treatment line with Life Cycle Assessment.

    PubMed

    Remy, C; Lesjean, B; Waschnewski, J

    2013-01-01

    This study exemplifies the use of Life Cycle Assessment (LCA) as a tool to quantify the environmental impacts of processes for wastewater treatment. In a case study, the sludge treatment line of a large wastewater treatment plant (WWTP) is analysed in terms of cumulative energy demand and the emission of greenhouse gases (carbon footprint). Sludge treatment consists of anaerobic digestion, dewatering, drying, and disposal of stabilized sludge in mono- or co-incineration in power plants or cement kilns. All relevant forms of energy demand (electricity, heat, chemicals, fossil fuels, transport) and greenhouse gas emissions (fossil CO(2), CH(4), N(2)O) are accounted in the assessment, including the treatment of return liquor from dewatering in the WWTP. Results show that the existing process is positive in energy balance (-162 MJ/PE(COD) * a) and carbon footprint (-11.6 kg CO(2)-eq/PE(COD) * a) by supplying secondary products such as electricity from biogas production or mono-incineration and substituting fossil fuels in co-incineration. However, disposal routes for stabilized sludge differ considerably in their energy and greenhouse gas profiles. In total, LCA proves to be a suitable tool to support future investment decisions with information of environmental relevance on the impact of wastewater treatment, but also urban water systems in general.

  17. Evaluation of the Hydraulic Capacity and Mass Transfer Efficiency of the CSSX Process with the Optimized Solvent in a Single Stage of 5.5-cm-Diameter Centrifugal Contactor

    SciTech Connect

    Law, Jack Douglas; Tillotson, Richard Dean; Todd, Terry Allen

    2002-09-01

    The Caustic-Side Solvent Extraction (CSSX) process has been selected for the separation of cesium from Savannah River Site high-level waste. The solvent composition used in the CSSX process was recently optimized so that the solvent is no longer supersaturated with respect to the calixarene crown ether extractant. Hydraulic performance and mass transfer efficiency testing of a single stage of 5.5-cm ORNL-designed centrifugal contactor has been performed for the CSSX process with the optimized solvent. Maximum throughputs of the 5.5-cm centrifugal contactor, as a function of contactor rotor speed, have been measured for the extraction, scrub, strip, and wash sections of the CSSX flowsheet at the baseline organic/aqueous flow ratios (O/A) of the process, as well as at O/A’s 20% higher and 20% lower than the baseline. Maximum throughputs are comparable to the design throughput of the contactor, as well as with throughputs obtained previously in a 5-cm centrifugal contactor with the non-optimized CSSX solvent formulation. The 20% variation in O/A had minimal effect on contactor throughput. Additionally, mass transfer efficiencies have been determined for the extraction and strip sections of the flowsheet. Efficiencies were lower than the process goal of greater than or equal to 80%, ranging from 72 to 75% for the extraction section and from 36 to 60% in the strip section. Increasing the mixing intensity and/or the solution level in the mixing zone of the centrifugal contactor (residence time) could potentially increase efficiencies. Several methods are available to accomplish this including (1) increasing the size of the opening in the bottom of the rotor, resulting in a contactor which is partially pumping instead of fully pumping, (2) decreasing the number of vanes in the contactor, (3) increasing the vane height, or (4) adding vanes on the rotor and baffles on the housing of the contactor. The low efficiency results obtained stress the importance of proper design

  18. Evaluation of the Hydraulic Performance and Mass Transfer Efficiency of the CSSX Process with the Optimized Solvent in a Single Stage of 5.5-Cm Diameter Centrifugal Contactor

    SciTech Connect

    Law, J.D.; Tillotson, R.D.; Todd, T.A.

    2002-09-19

    The Caustic-Side Solvent Extraction (CSSX) process has been selected for the separation of cesium from Savannah River Site high-level waste. The solvent composition used in the CSSX process was recently optimized so that the solvent is no longer supersaturated with respect to the calixarene crown ether extractant. Hydraulic performance and mass transfer efficiency testing of a single stage of 5.5-cm ORNL-designed centrifugal contactor has been performed for the CSSX process with the optimized solvent. Maximum throughputs of the 5.5-cm centrifugal contactor, as a function of contactor rotor speed, have been measured for the extraction, scrub, strip, and wash sections of the CSSX flowsheet at the baseline organic/aqueous flow ratios (O/A) of the process, as well as at O/A's 20% higher and 20% lower than the baseline. Maximum throughputs are comparable to the design throughput of the contactor, as well as with throughputs obtained previously in a 5-cm centrifugal contactor with the non-optimized CSSX solvent formulation. The 20% variation in O/A had minimal effect on contactor throughput. Additionally, mass transfer efficiencies have been determined for the extraction and strip sections of the flowsheet. Efficiencies were lower than the process goal of greater than or equal to 80%, ranging from 72 to 75% for the extraction section and from 36 to 60% in the strip section. Increasing the mixing intensity and/or the solution level in the mixing zone of the centrifugal contactor (residence time) could potentially increase efficiencies. Several methods are available to accomplish this including (1) increasing the size of the opening in the bottom of the rotor, resulting in a contactor which is partially pumping instead of fully pumping, (2) decreasing the number of vanes in the contactor, (3) increasing the vane height, or (4) adding vanes on the rotor and baffles on the housing of the contactor. The low efficiency results obtained stress the importance of proper design of

  19. Fast freeze-drying cycle design and optimization using a PAT based on the measurement of product temperature.

    PubMed

    Bosca, Serena; Barresi, Antonello A; Fissore, Davide

    2013-10-01

    This paper is focused on the use of an innovative Process Analytical Technology for the fast design and optimization of freeze-drying cycles for pharmaceuticals. The tool is based on a soft-sensor, a device that uses the experimental measure of product temperature during freeze-drying, a mathematical model of the process, and the Extended Kalman Filter algorithm to estimate the sublimation flux, the residual amount of ice in the vial, and some model parameters (heat and mass transfer coefficients). The accuracy of the estimations provided by the soft-sensor has been shown using as test case aqueous solutions containing different excipients (sucrose, polyvinylpyrrolidone), processed at various operating conditions, pointing out that the soft-sensor allows a fast estimation of model parameters and product dynamics without involving expensive hardware or time consuming analysis. The possibility of using the soft-sensor to calculate in-line (or off-line) the design space of the primary drying phase is here presented and discussed. Results evidences that by this way, it is possible to identify the values of the heating fluid temperature that maintain product temperature below the limit value, as well as the operating conditions that maximize the sublimation flux. Various experiments have been carried out to test the effectiveness of the proposed approach for a fast design of the cycle, evidencing that drying time can be significantly reduced, without impairing product quality.

  20. Performance Optimization of an Air-Standard Irreversible Dual-Atkinson Cycle Engine Based on the Ecological Coefficient of Performance Criterion

    PubMed Central

    Gonca, Guven; Sahin, Bahri

    2014-01-01

    This paper presents an ecological performance analysis and optimization for an air-standard irreversible Dual-Atkinson cycle (DAC) based on the ecological coefficient of performance (ECOP) criterion which includes internal irreversibilities, heat leak, and finite-rate of heat transfer. A comprehensive numerical analysis has been realized so as to investigate the global and optimal performances of the cycle. The results obtained based on the ECOP criterion are compared with a different ecological function which is named as the ecologic objective-function and with the maximum power output conditions. The results have been attained introducing the compression ratio, cut-off ratio, pressure ratio, Atkinson cycle ratio, source temperature ratio, and internal irreversibility parameter. The change of cycle performance with respect to these parameters is investigated and graphically presented. PMID:25170525

  1. Development of a novel naphthoic acid ionic liquid and its application in "no-organic solvent microextraction" for determination of triclosan and methyltriclosan in human fluids and the method optimization by central composite design.

    PubMed

    Wang, Hui; Gao, Jiajia; Yu, Nana; Qu, Jingang; Fang, Fang; Wang, Huili; Wang, Mei; Wang, Xuedong

    2016-07-01

    In traditional ionic liquids (ILs)-based microextraction, the hydrophobic and hydrophilic ILs are often used as extractant and disperser, respectively. However, the functional effects of ILs are not utilized in microextraction procedures. Herein, we introduced 1-naphthoic acid into imidazolium ring to synthesize a novel ionic liquid 1-butyl-3-methylimidazolium naphthoic acid salt ([C4MIM][NPA]), and its structure was characterized by IR, (1)H NMR and MS. On the basis of its acidic property and lower solubility than common [CnMIM][BF4], it was used as a mixing dispersive solvent with [C4MIM][BF4] in "functionalized ionic liquid-based no organic solvent microextraction (FIL-NOSM)". Utilization of [C4MIM][NPA] in FIL-NOSM procedures has two obvious advantages: (1) it promoted the non-polar environment, increased volume of the sedimented phase, and thus could enhance the extraction recoveries of triclosan (TCS) and methyltriclosan (MTCS) by more than 10%; and (2) because of the acidic property, it can act as a pH modifier, avoiding extra pH adjustment step. By combining single factor optimization and central composite design, the main factors in the FIL-NOSM method were optimized. Under the optimal conditions, the relative recoveries of TCS and MTCS reached up to 98.60-106.09%, and the LODs of them were as low as 0.12-0.15µgL(-1) in plasma and urine samples. In total, this [C4MIM][NPA]-based FIL-NOSM method provided high extraction efficiency, and required less pretreatment time and unutilized any organic solvent. To the best of our knowledge, this is the first application of [C4mim][NPA]-based microextraction method for the simultaneous quantification of trace TCS and MTCS in human fluids.

  2. Computing conformational free energy differences in explicit solvent: An efficient thermodynamic cycle using an auxiliary potential and a free energy functional constructed from the end points.

    PubMed

    Harris, Robert C; Deng, Nanjie; Levy, Ronald M; Ishizuka, Ryosuke; Matubayasi, Nobuyuki

    2016-12-23

    Many biomolecules undergo conformational changes associated with allostery or ligand binding. Observing these changes in computer simulations is difficult if their timescales are long. These calculations can be accelerated by observing the transition on an auxiliary free energy surface with a simpler Hamiltonian and connecting this free energy surface to the target free energy surface with free energy calculations. Here, we show that the free energy legs of the cycle can be replaced with energy representation (ER) density functional approximations. We compute: (1) The conformational free energy changes for alanine dipeptide transitioning from the right-handed free energy basin to the left-handed basin and (2) the free energy difference between the open and closed conformations of β-cyclodextrin, a "host" molecule that serves as a model for molecular recognition in host-guest binding. β-cyclodextrin contains 147 atoms compared to 22 atoms for alanine dipeptide, making β-cyclodextrin a large molecule for which to compute solvation free energies by free energy perturbation or integration methods and the largest system for which the ER method has been compared to exact free energy methods. The ER method replaced the 28 simulations to compute each coupling free energy with two endpoint simulations, reducing the computational time for the alanine dipeptide calculation by about 70% and for the β-cyclodextrin by > 95%. The method works even when the distribution of conformations on the auxiliary free energy surface differs substantially from that on the target free energy surface, although some degree of overlap between the two surfaces is required. © 2016 Wiley Periodicals, Inc.

  3. Stoddard solvent poisoning

    MedlinePlus

    These products contain Stoddard solvent: Dry cleaning fluids Paints Paint thinner Stoddard solvent ( mineral spirits ) Toners used in copy machines This list may not include all products containing Stoddard solvent.

  4. Influence of processing procedure on the quality of Radix Scrophulariae: a quantitative evaluation of the main compounds obtained by accelerated solvent extraction and high-performance liquid chromatography.

    PubMed

    Cao, Gang; Wu, Xin; Li, Qinglin; Cai, Hao; Cai, Baochang; Zhu, Xuemei

    2015-02-01

    An improved high-performance liquid chromatography with diode array detection combined with accelerated solvent extraction method was used to simultaneously determine six compounds in crude and processed Radix Scrophulariae samples. Accelerated solvent extraction parameters such as extraction solvent, temperature, number of cycles, and analysis procedure were systematically optimized. The results indicated that compared with crude Radix Scrophulariae samples, the processed samples had lower contents of harpagide and harpagoside but higher contents of catalpol, acteoside, angoroside C, and cinnamic acid. The established method was sufficiently rapid and reliable for the global quality evaluation of crude and processed herbal medicines.

  5. Optimization of the cycle life performance of VRLA batteries, working under high rate, partial state of charge (HRPSOC) conditions

    NASA Astrophysics Data System (ADS)

    Fernández, M.; Trinidad, F.; Valenciano, J.; Sánchez, A.

    On hybrid vehicle applications, batteries must work in a rather low state of charge (SOC), in order to be able to recover as much of the regenerative braking energy as possible. Usually SOC values around 60% are used, which promotes the development of new unexpected failure modes not previously found, mainly associated with heavy sulphation of the negative plates. In order to try to optimise the cycle life performance to the point of making these batteries a real alternative for the application of hybrid vehicles, a series of tests have been undertaken, aimed to optimise the key parameters that from previous experience are known to determine life duration in high rate low state of charge (HRPSOC) conditions. Previous works have been focused on trying to determine the optimum composition of positive and negative active material, concerning paste density in the positive, and additives in negative. In order to overcome the deleterious effect of heavy sulphation in negative plates on cycle life, the use of conductivity enhancers additives such as graphite has been proposed. The objective of this project is to optimize the performance of the glass microfiber separators, in order to maintain a high degree of compression in the group, as well as to avoid acid stratification and development of short circuits along the battery life. To do this, different glass microfiber separators with inert additives, as well as different fiber composition have been tested. Results obtained up to now, indicate a remarkable good performance of the VRLA batteries with the new separators containing very fine fiberglass and silica fillers as an additive.

  6. STATE-OF-THE-ART AND EMERGING TRUCK ENGINE TECHNOLOGIES FOR OPTIMIZED PERFORMANCE, EMISSIONS AND LIFE CYCLE COSTS

    SciTech Connect

    Schittler, M

    2003-08-24

    The challenge for truck engine product engineering is not only to fulfill increasingly stringent emission requirements, but also to improve the engine's economical viability in its role as the backbone of our global economy. While societal impact and therefore emission limit values are to be reduced in big steps, continuous improvement is not enough but technological quantum leaps are necessary. The introduction and refinement of electronic control of all major engine systems has already been a quantum leap forward. Maximizing the benefits of these technologies to customers and society requires full use of parameter optimization and other enabling technologies. The next big step forward will be widespread use of exhaust aftertreatment on all transportation related diesel engines. While exhaust gas aftertreatment has been successfully established on gasoline (Otto cycle) engines, the introduction of exhaust aftertreatment especially for heavy-duty diesel engines will be much mo re demanding. Implementing exhaust gas aftertreatment into commercial vehicle applications is a challenging task but the emission requirements to be met starting in Europe, the USA and Japan in the 2005-2007 timeframe require this step. The engine industry will be able to implement the new technology if all stakeholders support the necessary decisions. One decision has already been taken: the reduction of sulfur in diesel fuel being comparable with the elimination of lead in gasoline as a prerequisite for the three-way catalyst. Now we have the chance to optimize ecology and economy of the Diesel engine simultaneously by taking the decision to provide an additional infrastructure for a NOx reduction agent needed for the introduction of the Selective Catalytic Reduction (SCR) technology that is already implemented in the electric power generation industry. This requires some effort, but the resulting societal benefits, fuel economy and vehicle life cycle costs are significantly better when

  7. Process for hydrogenating coal and coal solvents

    DOEpatents

    Tarrer, Arthur R.; Shridharani, Ketan G.

    1983-01-01

    A novel process is described for the hydrogenation of coal by the hydrogenation of a solvent for the coal in which the hydrogenation of the coal solvent is conducted in the presence of a solvent hydrogenation catalyst of increased activity, wherein the hydrogenation catalyst is produced by reacting ferric oxide with hydrogen sulfide at a temperature range of 260.degree. C. to 315.degree. C. in an inert atmosphere to produce an iron sulfide hydrogenation catalyst for the solvent. Optimally, the reaction temperature is 275.degree. C. Alternately, the reaction can be conducted in a hydrogen atmosphere at 350.degree. C.

  8. Solvent wash solution

    DOEpatents

    Neace, J.C.

    1984-03-13

    A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

  9. Solvent wash solution

    DOEpatents

    Neace, James C.

    1986-01-01

    Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

  10. Optimization of conditions of solvent-free microwave extraction and study on antioxidant capacity of essential oil from Schisandra chinensis (Turcz.) Baill.

    PubMed

    Ma, Chun-hui; Yang, Lei; Zu, Yuan-gang; Liu, Ting-ting

    2012-10-15

    In this article, solvent-free microwave extraction (SFME) of essential oil from Schisandra chinensis (Turcz.) Baill was studied. A multivariate study based on central composite design (CCD) was used to evaluate the influence of three major variables affecting the performance of SFME. The optimum parameters were extraction time 30 min, irradiation power 385 W and moisture content of the fruits was 68%. The extraction yield of essential oil was 11 ml/kg under the optimum conditions. The antioxidant capacity of essential oils extracted by different methods were determined, and compared with traditional antioxidants. GC-MS showed the different composition of essential oil extracted by hydro-distillation (HD), steam-distillation (SD) and SFME. S. chinensis materials treated by different methods were observed by scanning electronic microscopy (SEM) and thermo-gravimetric analysis (TGA). Micrographs and thermo gravimetric loss provided more evidences to prove SFME of essential oil is more completed than HD and SD.

  11. Advanced steam power plant concepts with optimized life-cycle costs: A new approach for maximum customer benefit

    SciTech Connect

    Seiter, C.

    1998-07-01

    The use of coal power generation applications is currently enjoying a renaissance. New highly efficient and cost-effective plant concepts together with environmental protection technologies are the main factors in this development. In addition, coal is available on the world market at attractive prices and in many places it is more readily available than gas. At the economical leading edge, standard power plant concepts have been developed to meet the requirements of emerging power markets. These concepts incorporate the high technological state-of-the-art and are designed to achieve lowest life-cycle costs. Low capital cost, fuel costs and operating costs in combination with shortest lead times are the main assets that make these plants attractive especially for IPPs and Developers. Other aspects of these comprehensive concepts include turnkey construction and the willingness to participate in BOO/BOT projects. One of the various examples of such a concept, the 2 x 610-MW Paiton Private Power Project Phase II in Indonesia, is described in this paper. At the technological leading edge, Siemens has always made a major contribution and was pacemaker for new developments in steam power plant technology. Modern coal-fired steam power plants use computer-optimized process and plant design as well as advanced materials, and achieve efficiencies exceeding 45%. One excellent example of this high technology is the world's largest lignite-fired steam power plant Schwarze Pumpe in Germany, which is equipped with two 800 MW Siemens steam turbine generators with supercritical steam parameters. The world's largest 50-Hz single-shaft turbine generator with supercritical steam parameters rated at 1025 MW for the Niederaussem lignite-fired steam power plant in Germany is a further example of the sophisticated Siemens steam turbine technology and sets a new benchmark in this field.

  12. Life-cycle evaluation of nitrogen-use in rice-farming systems: implications for economically-optimal nitrogen rates

    NASA Astrophysics Data System (ADS)

    Xia, Y.; Yan, X.

    2011-11-01

    Nitrogen (N) fertilizer plays an important role in agricultural systems in terms of food yield. However, N application rates (NARs) are often overestimated over the rice (Oryza sativa L.) growing season in the Taihu Lake region of China. This is largely because negative externalities are not entirely included when evaluating economically-optimal nitrogen rate (EONR), such as only individual N losses are taken into account, or the inventory flows of reactive N have been limited solely to the farming process when evaluating environmental and economic effects of N fertilizer. This study integrates important material and energy flows resulting from N use into a rice agricultural inventory that constitutes the hub of the life-cycle assessment (LCA) method. An economic evaluation is used to determine an environmental and economic NAR for the Taihu Lake region. The analysis reveals that production and exploitation processes consume the largest proportion of resources, accounting for 77.2 % and 22.3 % of total resources, respectively. Regarding environmental impact, global warming creates the highest cost with contributions stemming mostly from fertilizer production and farming processes. Farming process incurs the biggest environmental impact of the three environmental impact categories considered, whereas transportation has a much smaller effect. When taking account of resource consumption and environmental cost, the marginal benefit of 1 kg rice would decrease from 2.4 to only 1.05 yuan. Accordingly, our current EONR has been evaluated at 187 kg N ha-1 for a single rice-growing season. This could enhance profitability, as well as reduce the N losses associated with rice growing.

  13. Optimism

    PubMed Central

    Carver, Charles S.; Scheier, Michael F.; Segerstrom, Suzanne C.

    2010-01-01

    Optimism is an individual difference variable that reflects the extent to which people hold generalized favorable expectancies for their future. Higher levels of optimism have been related prospectively to better subjective well-being in times of adversity or difficulty (i.e., controlling for previous well-being). Consistent with such findings, optimism has been linked to higher levels of engagement coping and lower levels of avoidance, or disengagement, coping. There is evidence that optimism is associated with taking proactive steps to protect one's health, whereas pessimism is associated with health-damaging behaviors. Consistent with such findings, optimism is also related to indicators of better physical health. The energetic, task-focused approach that optimists take to goals also relates to benefits in the socioeconomic world. Some evidence suggests that optimism relates to more persistence in educational efforts and to higher later income. Optimists also appear to fare better than pessimists in relationships. Although there are instances in which optimism fails to convey an advantage, and instances in which it may convey a disadvantage, those instances are relatively rare. In sum, the behavioral patterns of optimists appear to provide models of living for others to learn from. PMID:20170998

  14. Decision Support Requirements in a Unified Life Cycle Engineering (ULCE) Environment. Volume 2. Conceptual Approaches to Optimization.

    DTIC Science & Technology

    1988-05-01

    necessary and sufficient conditions ( optimality conditions ) that should be satisfied by an optimum in order to... conditions . The necessary conditions of optimality refer to those conditions that an optimum point must satisfy. However, it is possible that a...point. The nature (maximum, minimum, etc.) of a stationary point is determined then using the sufficient optimality conditions . 8 * • Several topics

  15. Solvents in novolak synthesis

    NASA Astrophysics Data System (ADS)

    Sobodacha, Chet J.; Lynch, Thomas J.; Durham, Dana L.; Paradis, Valerie R.

    1993-09-01

    Novolac resins may be prepared with or without a solvent present. We have found that solvent power greatly affects the properties of the finished resin and thus gives the resist chemist another variable with which to `fine-tune' resist properties. Using designed experiments, we investigated the effect of solvent power, as measured by Hansen's Solubility Parameters, of a number of solvents and solvent mixtures on the final properties of the novolac resin. We found that the relative molecular weight (RMW) and dissolution rate of a novolac resin can be varied by selection of a solvent or solvent mixture with the appropriate polarity and hydrogen- bonding characteristics. The solvent polarity and hydrogen-bonding characteristics may affect the stability of the cresol/formaldehyde transition state, thus causing the observed changes in RMW and dissolution rate.

  16. Solvent Recycling for Shipyards

    DTIC Science & Technology

    1993-05-01

    alternatives to solvent cleaning. Typical equipment types that can be effectively cleaned with recycled solvents include spray guns paint hoses pumps...in place of solvent-based coatings; or equipment changes, such as the use of airless or HVLP systems to reduce paint consumption and overspray...Using mechanical cleaning methods instead of solvent cleaning Change from conventional painting to solventless processes such as thermal spray or powder

  17. NEPTUNIUM SOLVENT EXTRACTION PROCESS

    DOEpatents

    Dawson, L.R.; Fields, P.R.

    1959-10-01

    The separation of neptunium from an aqueous solution by solvent extraction and the extraction of neptunium from the solvent solution are described. Neptunium is separated from an aqueous solution containing tetravalent or hexavalent neptunium nitrate, nitric acid, and a nitrate salting out agent, such as sodium nitrate, by contacting the solution with an organic solvent such as diethyl ether. Subsequently, the neptunium nitrate is extracted from the organic solvent extract phase with water.

  18. Solvents and sustainable chemistry

    PubMed Central

    Welton, Tom

    2015-01-01

    Solvents are widely recognized to be of great environmental concern. The reduction of their use is one of the most important aims of green chemistry. In addition to this, the appropriate selection of solvent for a process can greatly improve the sustainability of a chemical production process. There has also been extensive research into the application of so-called green solvents, such as ionic liquids and supercritical fluids. However, most examples of solvent technologies that give improved sustainability come from the application of well-established solvents. It is also apparent that the successful implementation of environmentally sustainable processes must be accompanied by improvements in commercial performance. PMID:26730217

  19. Solvent recycle/recovery

    SciTech Connect

    Paffhausen, M.W.; Smith, D.L.; Ugaki, S.N.

    1990-09-01

    This report describes Phase I of the Solvent Recycle/Recovery Task of the DOE Chlorinated Solvent Substitution Program for the US Air Force by the Idaho National Engineering Laboratory, EG G Idaho, Inc., through the US Department of Energy, Idaho Operations Office. The purpose of the task is to identify and test recovery and recycling technologies for proposed substitution solvents identified by the Biodegradable Solvent Substitution Program and the Alternative Solvents/Technologies for Paint Stripping Program with the overall objective of minimizing hazardous wastes. A literature search to identify recycle/recovery technologies and initial distillation studies has been conducted. 4 refs.

  20. Solute-solvent interactions in micellar electrokinetic chromatography. 6. Optimization of the selectivity of lithium dodecyl sulfate-lithium perfluorooctanesulfonate mixed micellar buffers.

    PubMed

    Fuguet, Elisabet; Ràfols, Clara; Torres-Lapasió, José Ramón; García-Alvarez-Coque, María Celia; Bosch, Elisabeth; Rosés, Martí

    2002-09-01

    The optimization of the composition of mixed surfactants used as micellar electrokinetic chromatography (MEKC) pseudostationary phases is proposed as an effective method for the separation of complex mixtures of analytes. The solvation parameter model is used to select two surfactants (lithium dodecyl sulfate, LDS, and lithium perfluorooctanesulfonate, LPFOS) with contrasting solvation properties. Combination of these two surfactants allows variations of the solvation properties of MEKC pseudostationary phase along a wide range. Thus, the convenient variation of the proportion of both surfactants allows an effective control of the selectivity in such systems. An algorithm that predicts the overall resolution of a given mixture of compounds is described and applied to optimize the composition of the mixed surfactant for the separation of the mixture. The algorithm is based on the calculation of peak purities on simulated chromatograms as a function of the composition of the mixed LDS/LPFOS micellar buffer from data at several micellar buffer compositions. Successful separations were achieved for mixtures containing up to 20 compounds, in less than 12 min.

  1. Efficient removal of naphthalene-2-ol from aqueous solutions by solvent extraction.

    PubMed

    Shao, Jingjing; Cheng, Yan; Yang, Chunping; Zeng, Guangming; Liu, Wencan; Jiao, Panpan; He, Huijun

    2016-09-01

    Naphthalene-2-ol is a typical biologically recalcitrant pollutant in dye wastewater. Solvent extraction of naphthalene-2-ol from aqueous solutions using mixed solvents was investigated. Various extractants and diluents were evaluated, and the effects of volume ratio of extractant to diluent, initial pH, initial concentration of naphthalene-2-ol in aqueous solution, extraction time, temperature, volume ratio of organic phase to aqueous phase (O/A), stirring rate and extraction stages, on extraction efficiency were examined separately. Regeneration and reuse of the spent extractant were also investigated. Results showed that tributyl phosphate (TBP) achieved 98% extraction efficiency for naphthalene-2-ol in a single stage extraction, the highest among the 12 extractants evaluated. Extraction efficiency was optimized when cyclohexane and n-octane were used as diluents. The solvent combination of 20% TBP, 20% n-octanol and 60% cyclohexane (V/V) obtained the maximum extraction efficiency for naphthalene-2-ol, 99.3%, within 20min using three cross-current extraction stages under the following extraction conditions: O/A ratio of 1:1, initial pH of 3, 25°C and stirring rate of 150r/min. Recovery of mixed solvents was achieved by using 15% (W/W) NaOH solution at an O:A ratio of 1:1 and a contact time of 15min. The mixed solvents achieved an extraction capacity for naphthalene-2-ol stably higher than 90% during five cycles after regeneration.

  2. Life cycle thinking and assessment tools on environmentally-benign electronics: Convergent optimization of materials use, end-of-life strategy and environmental policies

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoying

    The purpose of this study is to integrate the quantitative environmental performance assessment tools and the theory of multi-objective optimization within the boundary of electronic product systems to support the selection among design alternatives in terms of environmental impact, technical criteria, and economic feasibility. To meet with the requirements that result from emerging environmental legislation targeting electronics products, the research addresses an important analytical methodological approach to facilitate environmentally conscious design and end-of-life management with a life cycle viewpoint. A synthesis of diverse assessment tools is applied on a set of case studies: lead-free solder materials selection, cellular phone design, and desktop display technology assessment. In the first part of this work, an in-depth industrial survey of the status and concerns of the U.S. electronics industry on the elimination of lead (Pb) in solders is described. The results show that the trade-offs among environmental consequences, technology challenges, business risks, legislative compliance and stakeholders' preferences must be explicitly, simultaneously, and systematically addressed in the decision-making process used to guide multi-faceted planning of environmental solutions. In the second part of this work, the convergent optimization of the technical cycle, economic cycle and environmental cycle is addressed in a coherent and systematic way using the application of environmentally conscious design of cellular phones. The technical understanding of product structure, components analysis, and materials flow facilitates the development of "Design for Disassembly" guidelines. A bottom-up disassembly analysis on a "bill of materials" based structure at a micro-operational level is utilized to select optimal end-of-life strategies on the basis of economic feasibility. A macro-operational level life cycle model is used to investigate the environmental consequences

  3. A systematic optimization of medium chain fatty acid biosynthesis via the reverse beta-oxidation cycle in Escherichia coli.

    PubMed

    Wu, Junjun; Zhang, Xia; Xia, Xiudong; Dong, Mingsheng

    2017-04-06

    Medium-chain fatty acids (MCFAs, 6-10 carbons) are valuable precursors to many industrial biofuels and chemicals, recently engineered reversal of the β-oxidation (r-BOX) cycle has been proposed as a potential platform for efficient synthesis of MCFAs. Previous studies have made many exciting achievements on functionally characterizing four core enzymes of this r-BOX cycle. However, the information about bottleneck nodes in this cycle is elusive. Here, a quantitative assessment of the inherent limitations of this cycle was conducted to capitalize on its potential. The selection of the core β-oxidation reversal enzymes in conjunction with acetyl-CoA synthetase endowed the ability to synthesize about 1g/L MCFAs. Furthermore, a gene dosage experiment was developed to identify two rate-limiting enzymes (acetyl-CoA synthetase and thiolase). The de novo pathway was then separated into two modules at thiolase and MCFA production titer increased to 2.8g/L after evaluating different construct environments. Additionally, the metabolism of host organism was reprogrammed to the desired biochemical product by the clustered regularly interspaced short palindromic repeats interference system, resulted in a final MCFA production of 3.8g/L. These findings described here identified the inherent limitations of r-BOX cycle and further unleashed the lipogenic potential of this cycle, thus paving the way for the development of a bacterial platform for microbial production of high-value oleo-chemicals from low-value carbons in a sustainable and environmentally friendly manner.

  4. Optimizing modes of a small-scale combined-cycle power plant with atmospheric-pressure gasifier

    NASA Astrophysics Data System (ADS)

    Donskoi, I. G.; Marinchenko, A. Yu.; Kler, A. M.; Ryzhkov, A. F.

    2015-09-01

    The scheme of an integrated coal gasification combined-cycle power plant with small capacity is proposed. Using the built mathematical model a feasibility study of this unit was performed, taking into account the kinetics of physical and chemical transformations in the fuel bed. The estimates of technical and economic efficiency of the plant have been obtained and compared with the alternative options.

  5. Availability assessment of a centrifugal contactor solvent extraction system

    SciTech Connect

    Haire, M J; Grady, M S; Jubin, R T

    1985-08-01

    A systematic and detailed reliability, availability, and maintainability assessment was made of the preconceptual design of the Breeder Reprocessing Engineering Test solvent extraction system. Initially, the computed availability for the five cycles of solvent extraction was less than the goal for the facility. Contributions to the downtime were identified. Improvements in specifications, design, and equipment configurations that raise the predicted availability are recommended.

  6. The watershed-scale optimized and rearranged landscape design (WORLD) model and local biomass processing depots for sustainable biofuel production: Integrated life cycle assessments

    SciTech Connect

    Eranki, Pragnya L.; Manowitz, David H.; Bals, Bryan D.; Izaurralde, Roberto C.; Kim, Seungdo; Dale, Bruce E.

    2013-07-23

    An array of feedstock is being evaluated as potential raw material for cellulosic biofuel production. Thorough assessments are required in regional landscape settings before these feedstocks can be cultivated and sustainable management practices can be implemented. On the processing side, a potential solution to the logistical challenges of large biorefi neries is provided by a network of distributed processing facilities called local biomass processing depots. A large-scale cellulosic ethanol industry is likely to emerge soon in the United States. We have the opportunity to influence the sustainability of this emerging industry. The watershed-scale optimized and rearranged landscape design (WORLD) model estimates land allocations for different cellulosic feedstocks at biorefinery scale without displacing current animal nutrition requirements. This model also incorporates a network of the aforementioned depots. An integrated life cycle assessment is then conducted over the unified system of optimized feedstock production, processing, and associated transport operations to evaluate net energy yields (NEYs) and environmental impacts.

  7. Thermodynamic analysis and optimization of the cycle parameters of regenerative gas-turbine converters for solar power stations /SGTS/

    NASA Astrophysics Data System (ADS)

    Drabkin, L. M.

    A thermodynamic analysis compares the efficiency of a simple solar-driven helium gas turbine generator with two improved schemes employing regeneration of heat from the recirculating working fluid. One scheme uses a recuperator based on direct heat exchange while the other recovers heat by thermoelectric conversion in addition to the recuperator. The specific area of the heat exchange surface is calculated along with other system parameters for maximum thermodynamic cycle efficiency. Gains of up to 15% are demonstrated.

  8. SOLVENT EXTRACTION OF NEPTUNIUM

    DOEpatents

    Butler, J.P.

    1958-08-12

    A process is described for the recovery of neptuniunn from dissolver solutions by solvent extraction. The neptunium containing solution should be about 5N, in nitric acid.and about 0.1 M in ferrous ion. The organic extracting agent is tributyl phosphate, and the neptuniunn is recovered from the organic solvent phase by washing with water.

  9. Solvent-free synthesis

    EPA Science Inventory

    This chapter gives a brief introduction about solvent-free reactions whose importance can be gauged by the increasing number of publications every year during the last decade. The mechanistic aspects of the reactions under solvent-free conditions have been highlighted. Our observ...

  10. Comparison of Optimal Thermodynamic Models of the Tricarboxylic Acid Cycle from Heterotrophs, Cyanobacteria, and Green Sulfur Bacteria

    SciTech Connect

    Thomas, Dennis G.; Jaramillo Riveri, Sebastian I.; Baxter, Douglas J.; Cannon, William R.

    2014-12-15

    We have applied a new stochastic simulation approach to predict the metabolite levels, energy flow, and material flux in the different oxidative TCA cycles found in E. coli and Synechococcus sp. PCC 7002, and in the reductive TCA cycle typical of chemolithoautotrophs and phototrophic green sulfur bacteria such as Chlorobaculum tepidum. The simulation approach is based on equations of state and employs an assumption similar to that used in transition state theory. The ability to evaluate the thermodynamics of metabolic pathways allows one to understand the relationship between coupling of energy and material gradients in the environment and the selforganization of stable biological systems, and it is shown that each cycle operates in the direction expected due to its environmental niche. The simulations predict changes in metabolite levels and flux in response to changes in cofactor concentrations that would be hard to predict without an elaborate model based on the law of mass action. In fact, we show that a thermodynamically unfavorable reaction can still have flux in the forward direction when it is part of a reaction network. The ability to predict metabolite levels, energy flow and material flux should be significant for understanding the dynamics of natural systems and for understanding principles for engineering organisms for production of specialty chemicals, such as biofuels.

  11. Comparison of Optimal Thermodynamic Models of the Tricarboxylic Acid Cycle from Heterotrophs, Cyanobacteria, and Green Sulfur Bacteria.

    PubMed

    Thomas, Dennis G; Jaramillo-Riveri, Sebastian; Baxter, Douglas J; Cannon, William R

    2014-12-26

    We have applied a new stochastic simulation approach to predict the metabolite levels, material flux, and thermodynamic profiles of the oxidative TCA cycles found in E. coli and Synechococcus sp. PCC 7002, and in the reductive TCA cycle typical of chemolithoautotrophs and phototrophic green sulfur bacteria such as Chlorobaculum tepidum. The simulation approach is based on modeling states using statistical thermodynamics and employs an assumption similar to that used in transition state theory. The ability to evaluate the thermodynamics of metabolic pathways allows one to understand the relationship between coupling of energy and material gradients in the environment and the self-organization of stable biological systems, and it is shown that each cycle operates in the direction expected due to its environmental niche. The simulations predict changes in metabolite levels and flux in response to changes in cofactor concentrations that would be hard to predict without an elaborate model based on the law of mass action. In fact, we show that a thermodynamically unfavorable reaction can still have flux in the forward direction when it is part of a reaction network. The ability to predict metabolite levels, energy flow, and material flux should be significant for understanding the dynamics of natural systems and for understanding principles for engineering organisms for production of specialty chemicals.

  12. Alternative Green Solvents Project

    NASA Technical Reports Server (NTRS)

    Maloney, Phillip R.

    2012-01-01

    Necessary for safe and proper functioning of equipment. Mainly halogenated solvents. Tetrachloride, Trichloroethylene (TCE), CFC-113. No longer used due to regulatory/safety concerns. Precision Cleaning at KSC: Small % of total parts. Used for liquid oxygen (LOX) systems. Dual solvent process. Vertrel MCA (decafluoropentane (DFP) and trons-dichloroethylene) HFE-7100. DFP has long term environmental concerns. Project Goals: a) Identify potential replacements. b) 22 wet chemical processes. c) 3 alternative processes. d) Develop test procedures. e) Contamination and cleaning. f) Analysis. g) Use results to recommend alternative processes. Conclusions: a) No alternative matched Vertrel in this study. b) No clear second place solvent. c) Hydrocarbons- easy; Fluorinated greases- difficult. d) Fluorinated component may be needed in replacement solvent. e) Process may need to make up for shortcoming of the solvent. f) Plasma and SCC02 warrant further testing.

  13. Optimal Micro-Scale Secondary Flow Control for the Management of High Cycle Fatigue and Distortion in Compact Inlet Diffusers

    NASA Technical Reports Server (NTRS)

    Anderson, Bernhard H.; Keller, Dennis J.

    2002-01-01

    The purpose of this study on micro-scale secondary flow control (MSFC) is to study the aerodynamic behavior of micro-vane effectors through their factor (i.e., the design variable) interactions and to demonstrate how these statistical interactions, when brought together in an optimal manner, determine design robustness. The term micro-scale indicates the vane effectors are small in comparison to the local boundary layer height. Robustness in this situation means that it is possible to design fixed MSFC robust installation (i.e.. open loop) which operates well over the range of mission variables and is only marginally different from adaptive (i.e., closed loop) installation design, which would require a control system. The inherent robustness of MSFC micro-vane effector installation designs comes about because of their natural aerodynamic characteristics and the manner in which these characteristics are brought together in an optimal manner through a structured Response Surface Methodology design process.

  14. Towards ultra-fast solvent evaporation, the development of a computer controlled solvent vapor annealing chamber

    NASA Astrophysics Data System (ADS)

    Nelson, Gunnar; Wong, J.; Drapes, C.; Grant, M.; Baruth, A.

    Despite the promise of cheap and fast nanoscale ordering of block polymer thin films via solvent vapor annealing, a standardized, scalable production scheme remains elusive. Solvent vapor annealing exposes a nano-thin film to the vapors of one or more solvents with the goal of forming a swollen and mobile state to direct the self-assembly process by tuning surface energies and mediating unfavorable chain interactions. We have shown that optimized annealing conditions, where kinetic and thermal properties for crystal growth are extremely fast (<1s), exist at solvent concentrations just below the order-disorder transition of the film. However, when investigating the propagation of a given morphology into the bulk of a film during drying, the role of solvent evaporation comes under great scrutiny. During this process, the film undergoes a competition between two fronts; phase separation and kinetic trapping. Recent results in both theory and experiment point toward this critical element in controlling the resultant morphologies; however, no current method includes a controllable solvent evaporation rate at ultra-fast time scales. We report on a computer-controlled, pneumatically actuated chamber that provides control over solvent evaporation down to 15 ms. Furthermore, in situ spectral reflectance monitors solvent concentration with 10 ms temporal resolution and reveals several possible evaporation trajectories, ranging from linear to exponential to logarithmic. Funded by Dr. Randolph Ferlic Summer Research Scholarship and NASA Nebraska Space Grant.

  15. SOLVENT EXTRACTION PROCESS

    DOEpatents

    Jonke, A.A.

    1957-10-01

    In improved solvent extraction process is described for the extraction of metal values from highly dilute aqueous solutions. The process comprises contacting an aqueous solution with an organic substantially water-immiscible solvent, whereby metal values are taken up by a solvent extract phase; scrubbing the solvent extract phase with an aqueous scrubbing solution; separating an aqueous solution from the scrubbed solvent extract phase; and contacting the scrubbed solvent phase with an aqueous medium whereby the extracted metal values are removed from the solvent phase and taken up by said medium to form a strip solution containing said metal values, the aqueous scrubbing solution being a mixture of strip solution and an aqueous solution which contains mineral acids anions and is free of the metal values. The process is particularly effective for purifying uranium, where one starts with impure aqueous uranyl nitrate, extracts with tributyl phosphate dissolved in carbon tetrachloride, scrubs with aqueous nitric acid and employs water to strip the uranium from the scrubbed organic phase.

  16. SU-E-T-266: Development of Evaluation System of Optimal Synchrotron Controlling Parameter for Spot Scanning Proton Therapy with Multiple Gate Irradiations in One Operation Cycle

    SciTech Connect

    Yamada, T; Fujii, Y; Miyamoto, N; Matsuura, T; Takao, S; Matsuzaki, Y; Koyano, H; Shirato, H; Nihongi, H; Umezawa, M; Matsuda, K; Umegaki, K

    2015-06-15

    Purpose: We have developed a gated spot scanning proton beam therapy system with real-time tumor-tracking. This system has the ability of multiple-gated irradiation in a single synchrotron operation cycle controlling the wait-time for consecutive gate signals during a flat-top phase so that the decrease in irradiation efficiency induced by irregular variation of gate signal is reduced. Our previous studies have shown that a 200 ms wait-time is appropriate to increase the average irradiation efficiency, but the optimal wait-time can vary patient by patient and day by day. In this research, we have developed an evaluation system of the optimal wait-time in each irradiation based on the log data of the real-time-image gated proton beam therapy (RGPT) system. Methods: The developed system consists of logger for operation of RGPT system and software for evaluation of optimal wait-time. The logger records timing of gate on/off, timing and the dose of delivered beam spots, beam energy and timing of X-ray irradiation. The evaluation software calculates irradiation time in the case of different wait-time by simulating the multiple-gated irradiation operation using several timing information. Actual data preserved in the log data are used for gate on and off time, spot irradiation time, and time moving to the next spot. Design values are used for the acceleration and deceleration times. We applied this system to a patient treated with the RGPT system. Results: The evaluation system found the optimal wait-time of 390 ms that reduced the irradiation time by about 10 %. The irradiation time with actual wait-time used in treatment was reproduced with accuracy of 0.2 ms. Conclusion: For spot scanning proton therapy system with multiple-gated irradiation in one synchrotron operation cycle, an evaluation system of the optimal wait-time in each irradiation based on log data has been developed. Funding Support: Japan Society for the Promotion of Science (JSPS) through the FIRST

  17. Solvent alternatives guide

    SciTech Connect

    Elion, J.M.; Monroe, K.R.; Hill, E.A.

    1996-06-01

    It is no longer legal to manufacture or import chlorofluorocarbon 113 or methyl chloroform solvents, and companies that currently clean their parts with either material are now required to implement environmentally safe substitutes. To help find alternative methods, Research Triangle Institute`s Surface Cleaning Technology Program has designed a Solvent Alternatives Guide (SAGE), an online tool that enables access to practical information and recommendations for acceptable solvents. Developed in partnership with the US Environmental Protection Agency, SAGE is available free of charge on the Internet`s World Wide Web.

  18. Optimal Cycle Time and Preservation Technology Investment for Deteriorating Items with Price-sensitive Stock-dependent Demand Under Inflation

    NASA Astrophysics Data System (ADS)

    Shah, Nita H.; Shah, Arpan D.

    2014-04-01

    The article analyzes economic order quantity for the retailer who has to handle imperfect quality of the product and the units are subject to deteriorate at a constant rate. To control deterioration of the units in inventory, the retailer has to deploy advanced preservation technology. Another challenge for the retailer is to have perfect quality product. This requires mandatory inspection during the production process. This model is developed with the condition of random fraction of defective items. It is assumed that after inspection, the screened defective items are sold at a discounted rate instantly. Demand is considered to be price-sensitive stock-dependent. The model is incorporating effect of inflation which is critical factor globally. The objective is to maximize profit of the retailer with respect to preservation technology investment, order quantity and cycle time. The numerical example is given to validate the proposed model. Sensitivity analysis is carried out to work out managerial issues.

  19. CHLORINATED SOLVENT PLUME CONTROL

    EPA Science Inventory

    This lecture will cover recent success in controlling and assessing the treatment of shallow ground water plumes of chlorinated solvents, other halogenated organic compounds, and methyl tert-butyl ether (MTBE).

  20. Orthogonal test design for optimization of suitable conditions to separate C-phycocyanin from Spirulina platensis by high-speed counter-current chromatography using reverse micelle solvent system.

    PubMed

    Yin, Lianhong; Xu, Lina; Yu, Kun; Zhen, Yuhong; Han, Xu; Xu, Youwei; Qi, Yan; Peng, Jinyong; Tan, Aiping

    2011-06-01

    High-speed counter-current chromatography (HSCCC) was applied to separate C-phycocyanin (C-PC) from Spirulina platensis in the article. The suitable conditions were optimized by an orthogonal test design (L(9)(3)(3)), including the stationary phase of reverse micelle solvent system (0.10 g/mL cetyltrimethylammonium bromide [CTAB]/isooctane-hexylalcohol), mobile phase A (0.05 mol/L sodium phosphate buffer, pH 4.0, containing 0.2 mol/L KCl) and mobile phase B (0.05 mol/L sodium phosphate buffer, pH 8.0, containing 0.4 mol/L KCl). Under the selected conditions, 78.7 mg protein was purified from 200 mg crude extract of S. platensis, and the purity of the product was 4.25 based on the absorbance ratio of A(620)/A(280) , which was increased 6.85 times compared with the crude extract. Then, the protein was identified to be C-PC by MALDI-TOF/TOF-MS and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis compared with the standard. The application of HSCCC used in the separation of C-PC from S. platensis was first reported in the article. Furthermore, three kinds of tumor cell lines including human hepatoma cell line SMMC-7721, human ovarian carcinoma cell line ES-2, and human lung adenocarcinoma cell line SPCA-1 were used to evaluate the anticancer activities of the separated product, and the results showed that the separated C-PC had excellent anti-tumor actions with the IC(50) values at 2.998, 4.854, and 8.423 μg/mL, respectively, for 48 h treatment. The outcome indicates that an effective method for C-PC purification by HSCCC has been established.

  1. Continuous countercurrent membrane column for the separation of solute/solvent and solvent/solvent systems

    DOEpatents

    Nerad, Bruce A.; Krantz, William B.

    1988-01-01

    A reverse osmosis membrane process or hybrid membrane - complementary separator process for producing enriched product or waste streams from concentrated and dilute feed streams for both solvent/solvent and solute/solvent systems is described.

  2. SOLVENT EXTRACTION OF RUTHENIUM

    DOEpatents

    Hyman, H.H.; Leader, G.R.

    1959-07-14

    The separation of rathenium from aqueous solutions by solvent extraction is described. According to the invention, a nitrite selected from the group consisting of alkali nitrite and alkaline earth nitrite in an equimolecular quantity with regard to the quantity of rathenium present is added to an aqueous solution containing ruthenium tetrantrate to form a ruthenium complex. Adding an organic solvent such as ethyl ether to the resulting mixture selectively extracts the rathenium complex.

  3. Supercritical solvent coal extraction

    NASA Technical Reports Server (NTRS)

    Compton, L. E. (Inventor)

    1984-01-01

    Yields of soluble organic extract are increased up to about 50% by the supercritical extraction of particulate coal at a temperature below the polymerization temperature for coal extract fragments (450 C.) and a pressure from 500 psig to 5,000 psig by the conjoint use of a solvent mixture containing a low volatility, high critical temperature coal dissolution catalyst such as phenanthrene and a high volatility, low critical temperature solvent such as toluene.

  4. Cleaning without chlorinated solvents

    SciTech Connect

    Thompson, L.M.; Simandl, R.F.

    1994-12-31

    Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92%. The program has been a twofold effort. Vapor degreasers used in batch cleaning-operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting and bonding. Cleaning ability was determined using techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes and swelling of epoxies.

  5. Cleaning without chlorinated solvents

    NASA Technical Reports Server (NTRS)

    Thompson, L. M.; Simandl, R. F.

    1995-01-01

    Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92 percent. The program has been a twofold effort. Vapor degreasers used in batch cleaning operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting, and bonding. Cleaning ability was determined using techniques such as x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes, and swelling of epoxies.

  6. Parameter Optimization of a Box and a Three-Dimensional Ocean Carbon Cycle Model Using the Adjoint Method: What Can We Learn?

    NASA Astrophysics Data System (ADS)

    Tjiputra, J.; Winguth, A.

    2005-12-01

    A data assimilation technique is used to optimize marine ecosystem parameters that constraining carbon fluxes in a three-dimensional ocean carbon cycle model. An identical twin experiment is able to produce an a posteriori parameter set with significantly reduced model-data misfit. Error analysis using the Hessian matrix is applied to provide detailed information on the sensitivity of different parameters. Parameters associated with zooplankton grazing and phytoplankton growth reveal to be most sensitive with respect to surface chlorophyll concentration. In order to analyze the sensitivity of these parameters in more detail, biweekly BATS data are compared with a box model as well as with three-dimensional model. Interestingly, when different ocean regions are assimilated separately based on different physical and biogeochemical conditions, regional variation of ecosystem parameters significantly reduces the model-data misfit. Our results also show that certain regions need to have improved ecosystem model formulations in order to reduce the model data-misfit further.

  7. Systematic engineering of TCA cycle for optimal production of a four-carbon platform chemical 4-hydroxybutyric acid in Escherichia coli.

    PubMed

    Choi, Sol; Kim, Hyun Uk; Kim, Tae Yong; Lee, Sang Yup

    2016-11-01

    To address climate change and environmental problems, it is becoming increasingly important to establish biorefineries for the production of chemicals from renewable non-food biomass. Here we report the development of Escherichia coli strains capable of overproducing a four-carbon platform chemical 4-hybroxybutyric acid (4-HB). Because 4-HB production is significantly affected by aeration level, genome-scale metabolic model-based engineering strategies were designed under aerobic and microaerobic conditions with emphasis on oxidative/reductive TCA branches and glyoxylate shunt. Several different metabolic engineering strategies were employed to develop strains suitable for fermentation both under aerobic and microaerobic conditions. It was found that microaerobic condition was more efficient than aerobic condition in achieving higher titer and productivity of 4-HB. The final engineered strain produced 103.4g/L of 4-HB by microaerobic fed-batch fermentation using glycerol. The aeration-dependent optimization strategy of TCA cycle will be useful for developing microbial strains producing other reduced derivative chemicals of TCA cycle intermediates.

  8. Final Report: Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

    SciTech Connect

    Donna Post Guillen; Jalal Zia

    2013-09-01

    This research and development (R&D) project exemplifies a shared public private commitment to advance the development of energy efficient industrial technologies that will reduce the U.S. dependence upon foreign oil, provide energy savings and reduce greenhouse gas emissions. The purpose of this project was to develop and demonstrate a Direct Evaporator for the Organic Rankine Cycle (ORC) for the conversion of waste heat from gas turbine exhaust to electricity. In conventional ORCs, the heat from the exhaust stream is transferred indirectly to a hydrocarbon based working fluid by means of an intermediate thermal oil loop. The Direct Evaporator accomplishes preheating, evaporation and superheating of the working fluid by a heat exchanger placed within the exhaust gas stream. Direct Evaporation is simpler and up to 15% less expensive than conventional ORCs, since the secondary oil loop and associated equipment can be eliminated. However, in the past, Direct Evaporation has been avoided due to technical challenges imposed by decomposition and flammability of the working fluid. The purpose of this project was to retire key risks and overcome the technical barriers to implementing an ORC with Direct Evaporation. R&D was conducted through a partnership between the Idaho National Laboratory (INL) and General Electric (GE) Global Research Center (GRC). The project consisted of four research tasks: (1) Detailed Design & Modeling of the ORC Direct Evaporator, (2) Design and Construction of Partial Prototype Direct Evaporator Test Facility, (3) Working Fluid Decomposition Chemical Analyses, and (4) Prototype Evaluation. Issues pertinent to the selection of an ORC working fluid, along with thermodynamic and design considerations of the direct evaporator, were identified. The FMEA (Failure modes and effects analysis) and HAZOP (Hazards and operability analysis) safety studies performed to mitigate risks are described, followed by a discussion of the flammability analysis of the

  9. Assimilation of seasonal chlorophyll and nutrient data into an adjoint three-dimensional ocean carbon cycle model: Sensitivity analysis and ecosystem parameter optimization

    NASA Astrophysics Data System (ADS)

    Tjiputra, Jerry F.; Polzin, Dierk; Winguth, Arne M. E.

    2007-03-01

    An adjoint method is applied to a three-dimensional global ocean biogeochemical cycle model to optimize the ecosystem parameters on the basis of SeaWiFS surface chlorophyll observation. We showed with identical twin experiments that the model simulated chlorophyll concentration is sensitive to perturbation of phytoplankton and zooplankton exudation, herbivore egestion as fecal pellets, zooplankton grazing, and the assimilation efficiency parameters. The assimilation of SeaWiFS chlorophyll data significantly improved the prediction of chlorophyll concentration, especially in the high-latitude regions. Experiments that considered regional variations of parameters yielded a high seasonal variance of ecosystem parameters in the high latitudes, but a low variance in the tropical regions. These experiments indicate that the adjoint model is, despite the many uncertainties, generally capable to optimize sensitive parameters and carbon fluxes in the euphotic zone. The best fit regional parameters predict a global net primary production of 36 Pg C yr-1, which lies within the range suggested by Antoine et al. (1996). Additional constraints of nutrient data from the World Ocean Atlas showed further reduction in the model-data misfit and that assimilation with extensive data sets is necessary.

  10. Safe battery solvents

    DOEpatents

    Harrup, Mason K.; Delmastro, Joseph R.; Stewart, Frederick F.; Luther, Thomas A.

    2007-10-23

    An ion transporting solvent maintains very low vapor pressure, contains flame retarding elements, and is nontoxic. The solvent in combination with common battery electrolyte salts can be used to replace the current carbonate electrolyte solution, creating a safer battery. It can also be used in combination with polymer gels or solid polymer electrolytes to produce polymer batteries with enhanced conductivity characteristics. The solvents may comprise a class of cyclic and acyclic low molecular weight phosphazenes compounds, comprising repeating phosphorus and nitrogen units forming a core backbone and ion-carrying pendent groups bound to the phosphorus. In preferred embodiments, the cyclic phosphazene comprises at least 3 phosphorus and nitrogen units, and the pendent groups are polyethers, polythioethers, polyether/polythioethers or any combination thereof, and/or other groups preferably comprising other atoms from Group 6B of the periodic table of elements.

  11. Separation by solvent extraction

    DOEpatents

    Holt, Jr., Charles H.

    1976-04-06

    17. A process for separating fission product values from uranium and plutonium values contained in an aqueous solution, comprising adding an oxidizing agent to said solution to secure uranium and plutonium in their hexavalent state; contacting said aqueous solution with a substantially water-immiscible organic solvent while agitating and maintaining the temperature at from -1.degree. to -2.degree. C. until the major part of the water present is frozen; continuously separating a solid ice phase as it is formed; separating a remaining aqueous liquid phase containing fission product values and a solvent phase containing plutonium and uranium values from each other; melting at least the last obtained part of said ice phase and adding it to said separated liquid phase; and treating the resulting liquid with a new supply of solvent whereby it is practically depleted of uranium and plutonium.

  12. Solvent resistant copolyimide

    NASA Technical Reports Server (NTRS)

    Chang, Alice C. (Inventor); St. Clair, Terry L. (Inventor)

    1995-01-01

    A solvent resistant copolyimide was prepared by reacting 4,4'-oxydiphthalic anhydride with a diaimine blend comprising, based on the total amount of the diamine blend, about 75 to 90 mole percent of 3,4'-oxydianiline and about 10 to 25 mole percent p-phenylene diamine. The solvent resistant copolyimide had a higher glass transition temperature when cured at 350.degree. , 371.degree. and 400.degree. C. than LaRC.TM.-IA. The composite prepared from the copolyimide had similar mechanical properties to LaRC.TM.-IA. Films prepared from the copolyimide were resistant to immediate breakage when exposed to solvents such as dimethylacetamide and chloroform. The adhesive properties of the copolyimide were maintained even after testing at 23.degree., 150.degree., 177.degree. and 204.degree. C.

  13. Halogenated solvent remediation

    DOEpatents

    Sorenson, Jr., Kent S.

    2008-11-11

    Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

  14. Halogenated solvent remediation

    DOEpatents

    Sorenson, Kent S.

    2004-08-31

    Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.

  15. Rational development of solvent system families in counter-current chromatography.

    PubMed

    Friesen, J Brent; Pauli, Guido F

    2007-06-01

    Application of a mixture of 21 commercially available natural products, termed the GUESSmix, established a standard test that allows for a systematic analysis and comparison of the properties of biphasic solvent systems in counter-current/partition chromatography. Because the GUESSmix is comprised of compounds with varying polarities, functional groups, and structural features, it proves to be a rational method for mapping the optimal resolution polarity range of a particular solvent system. The mapping of optimal resolution polarity ranges of solvent systems provided for the description of the overall optimal resolution polarity range of a solvent system family, comprised of the same solvents in different proportions. By comparing the GUESSmix performance in the individual members of a solvent system family, the solvent system that best functions as the representative of, or portal to, the solvent system families was determined. The GUESSmix also afforded a method to compare the overall optimal resolution polarity ranges of solvent system families. Based on performance of GUESSmix chromatograms, the counter-current chromatography (CCC) properties of a two ternary literature solvent systems, ethyl acetate/n-butanol/water (EBuWat) and t-butylmethylether/acetonitrile/water (terAcWat), were explored in order to contrast and compare their CCC potential. A quaternary solvent system, hexane/t-butylmethylether/acetonitrile/water (HterAcWat), was also formulated and studied. The results indicated that the GUESSmix is fit for the purpose of developing and evaluating CCC solvent system families with desired performance characteristics.

  16. Solvent Reaction Field Potential inside an Uncharged Globular Protein: A Bridge between Implicit and Explicit Solvent Models?

    PubMed Central

    Baker, Nathan A.; McCammon, J. Andrew

    2008-01-01

    The solvent reaction field potential of an uncharged protein immersed in Simple Point Charge/Extended (SPC/E) explicit solvent was computed over a series of molecular dynamics trajectories, intotal 1560 ns of simulation time. A finite, positive potential of 13 to 24 kbTec−1 (where T = 300K), dependent on the geometry of the solvent-accessible surface, was observed inside the biomolecule. The primary contribution to this potential arose from a layer of positive charge density 1.0 Å from the solute surface, on average 0.008 ec/Å3, which we found to be the product of a highly ordered first solvation shell. Significant second solvation shell effects, including additional layers of charge density and a slight decrease in the short-range solvent-solvent interaction strength, were also observed. The impact of these findings on implicit solvent models was assessed by running similar explicit-solvent simulations on the fully charged protein system. When the energy due to the solvent reaction field in the uncharged system is accounted for, correlation between per-atom electrostatic energies for the explicit solvent model and a simple implicit (Poisson) calculation is 0.97, and correlation between per-atom energies for the explicit solvent model and a previously published, optimized Poisson model is 0.99. PMID:17949217

  17. Solvent extraction of phenols from water

    SciTech Connect

    Greminger, D.C.; Burns, G.P.; Lynn, S.; Hanson, D.H.; King, C.J.

    1980-02-01

    Methyl isobutyl ketone (MIBK) and diisopropyl ether (DIPE) have been evaluated as solvents for extraction of phenols, at high dilution, from water. Equilibrium distribution coefficients (K/sub D/) have been measured for phenol, dihydroxybenzenes and trihydroxybenzenes in both solvents as a function of pH. Particularly for the multihydric phenols, MIBK gives substantially higher values of K/sub D/ than does DIPE. The effect of pH can be described quantitatively through a simple ionization model, using published values of dissociation constants for the various phenols. Some method for removal of residual dissolved solvent must ordinarily be included in any extraction process for phenols. Possibilities include atmospheric-steam or inert-gas stripping, vacuum-steam stripping, and extraction with a second solvent. Vacuum-steam stripping is a particularly attractive choice for removal of MIBK; this reinforces the utility of MIBK as a solvent. The optimal temperature for vacuum stripping is generally the temperature of the extraction operation, which in turn is related to the effect of temperature on K/sub D/. Values of K/sub D/ for phenol-water-MIBK were determined at 30, 50, and 75/sup 0/C, and were found to decrease with increasing temperature at all concentrations.

  18. ONSITE SOLVENT RECOVERY

    EPA Science Inventory

    This study evaluated the product quality, waste reduction/pollution prevention, and economic aspects of three technologies for onsite solvent recovery. The technologies were (1) atmospheric batch distillation, (2) vacuum heat-pump distillation, and (3) low-emission vapor degreas...

  19. DESIGNING GREENER SOLVENTS

    EPA Science Inventory

    Computer-aided design of chemicals and chemical mixtures provides a powerful tool to help engineers identify cleaner process designs and more-benign alternatives to toxic industrial solvents. Three software programs are discussed: (1) PARIS II (Program for Assisting the Replaceme...

  20. Organic solvent topical report

    SciTech Connect

    Cowley, W.L.

    1998-04-30

    This report is the technical basis for the accident and consequence analyses used in the Hanford Tank Farms Basis for Interim Operation. The report also contains the scientific and engineering information and reference material needed to understand the organic solvent safety issue. This report includes comments received from the Chemical Reactions Subcommittee of the Tank Advisory Panel.

  1. Organic solvent topical report

    SciTech Connect

    COWLEY, W.L.

    1999-05-13

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an organic solvent fire is within risk evaluation guidelines. This report updates information contained in Analysis of Consequences of Postulated Solvent Fires in Hanford Site Waste Tanks. WHC-SD-WM-CN-032. Rev. 0A (Cowley et al. 1996). However, this document will not replace Cowley et al (1996) as the primary reference for the Basis for Interim Operation (BIO) until the recently submitted BIO amendment (Hanson 1999) is approved by the US Department of Energy. This conclusion depends on the use of controls for preventing vehicle fuel fires and for limiting the use of flame cutting in areas where hot metal can fall on the waste surface.The required controls are given in the Tank Waste Remediation System Technical Safety Requirements (Noorani 1997b). This is a significant change from the conclusions presented in Revision 0 of this report. Revision 0 of this calcnote concluded that some organic solvent fire scenarios exceeded risk evaluation guidelines, even with controls imposed.

  2. Solvent-Ion Interactions in Salt Water: A Simple Experiment.

    ERIC Educational Resources Information Center

    Willey, Joan D.

    1984-01-01

    Describes a procedurally quick, simple, and inexpensive experiment which illustrates the magnitude and some effects of solvent-ion interactions in aqueous solutions. Theoretical information, procedures, and examples of temperature, volume and hydration number calculations are provided. (JN)

  3. Correlation of radioactive-waste-treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: conversion of yellow cake to uranium hexafluoride. Part II. The solvent extraction-fluorination process

    SciTech Connect

    Sears, M.B.; Etnier, E.L.; Hill, G.S.; Patton, B.D.; Witherspoon, J.P.; Yen, S.N.

    1983-03-01

    A cost/benefit study was made to determine the cost and effectiveness of radioactive waste (radwaste) treatment systems for decreasing the release of radioactive materials and chemicals from a model uranium hexafluoride (UF/sub 6/) production plant using the solvent extraction-fluorination process, and to evaluate the radiological impact (dose commitment) of the release materials on the environment. The model plant processes 10,000 metric tons of uranium per year. Base-case waste treatment is the minimum necessary to operate the process. Effluents meet the radiological requirements listed in the Code of Federal Regulations, Title 10, Part 20 (10 CFR 20), Appendix B, Table II, but may not be acceptable chemically at all sites. Additional radwaste treatment techniques are applied to the base-case plant in a series of case studies to decrease the amounts of radioactive materials released and to reduce the amounts of radioactive materials released and to reduce the radiological dose commitment to the population in the surrounding area. The costs for the added waste treatment operations and the corresponding dose committment are correlated with the annual cost for treatment of the radwastes. The status of the radwaste treatment methods used in the case studies is discussed. Much of the technology used in the advanced cases will require development and demonstration, or else is proprietary and unavailable for immediate use. The methodology and assumptions for the radiological doses are found in ORNL-4992.

  4. Retailer's optimal credit period and cycle time in a supply chain for deteriorating items with up-stream and down-stream trade credits

    NASA Astrophysics Data System (ADS)

    Mahata, Gour Chandra

    2015-03-01

    In practice, the supplier often offers the retailers a trade credit period and the retailer in turn provides a trade credit period to her/his customer to stimulate sales and reduce inventory. From the retailer's perspective, granting trade credit not only increases sales and revenue but also increases opportunity cost (i.e., the capital opportunity loss during credit period) and default risk (i.e., the percentage that the customer will not be able to pay off his/her debt obligations). Hence, how to determine credit period is increasingly recognized as an important strategy to increase retailer's profitability. Also, the selling items such as fruits, fresh fishes, gasoline, photographic films, pharmaceuticals and volatile liquids deteriorate continuously due to evaporation, obsolescence and spoilage. In this paper, we propose an economic order quantity model for the retailer where (1) the supplier provides an up-stream trade credit and the retailer also offers a down-stream trade credit, (2) the retailer's down-stream trade credit to the buyer not only increases sales and revenue but also opportunity cost and default risk, and (3) the selling items are perishable. Under these conditions, we model the retailer's inventory system as a profit maximization problem to determine the retailer's optimal replenishment decisions under the supply chain management. We then show that the retailer's optimal credit period and cycle time not only exist but also are unique. We deduce some previously published results of other researchers as special cases. Finally, we use some numerical examples to illustrate the theoretical results.

  5. Systematic exploration of efficient strategies to manage solid waste in U.S. municipalities: perspectives from the solid waste optimization life-cycle framework (SWOLF).

    PubMed

    Levis, James W; Barlaz, Morton A; Decarolis, Joseph F; Ranjithan, S Ranji

    2014-04-01

    Solid waste management (SWM) systems must proactively adapt to changing policy requirements, waste composition, and an evolving energy system to sustainably manage future solid waste. This study represents the first application of an optimizable dynamic life-cycle assessment framework capable of considering these future changes. The framework was used to draw insights by analyzing the SWM system of a hypothetical suburban U.S. city of 100 000 people over 30 years while considering changes to population, waste generation, and energy mix and costs. The SWM system included 3 waste generation sectors, 30 types of waste materials, and 9 processes for waste separation, treatment, and disposal. A business-as-usual scenario (BAU) was compared to three optimization scenarios that (1) minimized cost (Min Cost), (2) maximized diversion (Max Diversion), and (3) minimized greenhouse gas (GHG) emissions (Min GHG) from the system. The Min Cost scenario saved $7.2 million (12%) and reduced GHG emissions (3%) relative to the BAU scenario. Compared to the Max Diversion scenario, the Min GHG scenario cost approximately 27% less and more than doubled the net reduction in GHG emissions. The results illustrate how the timed-deployment of technologies in response to changes in waste composition and the energy system results in more efficient SWM system performance compared to what is possible from static analyses.

  6. DESIGNING ENVIRONMENTALLY BENIGN SOLVENT SUBSTITUTES

    EPA Science Inventory

    Since the signing of 1987 Montreal Protocol, reducing and eliminating the use of harmful solvents has become an internationally imminent environmental protection mission. Solvent substitution is an effective way to achieve this goal. The Program for Assisting the Replacement of...

  7. Towards commercial scale postcombustion capture of CO2 with monoethanolamine solvent: key considerations for solvent management and environmental impacts.

    PubMed

    Reynolds, Alicia J; Verheyen, T Vincent; Adeloju, Samuel B; Meuleman, Erik; Feron, Paul

    2012-04-03

    Chemical absorption with aqueous amine solvents is the most advanced technology for postcombustion capture (PCC) of CO(2) from coal-fired power stations and a number of pilot scale programs are evaluating novel solvents, optimizing energy efficiency, and validating engineering models. This review demonstrates that the development of commercial scale PCC also requires effective solvent management guidelines to ensure minimization of potential technical and environmental risks. Furthermore, the review reveals that while solvent degradation has been identified as a key source of solvent consumption in laboratory scale studies, it has not been validated at pilot scale. Yet this is crucial as solvent degradation products, such as organic acids, can increase corrosivity and reduce the CO(2) absorption capacity of the solvent. It also highlights the need for the development of corrosion and solvent reclamation technologies, as well as strategies to minimize emissions of solvent and degradation products, such as ammonia, aldehydes, nitrosamines and nitramines, to the atmosphere from commercial scale PCC. Inevitably, responsible management of aqueous and solid waste will require more serious consideration. This will ultimately require effective waste management practices validated at pilot scale to minimize the likelihood of adverse human and environmental impacts from commercial scale PCC.

  8. Regenerative Heater Optimization for Steam Turbo-Generation Cycles of Generation IV Nuclear Power Plants with a Comparison of Two Concepts for the Westinghouse International Reactor Innovative and Secure (IRIS)

    SciTech Connect

    Williams, W.C.

    2002-08-01

    The intent of this study is to discuss some of the many factors involved in the development of the design and layout of a steam turbo-generation unit as part of a modular Generation IV nuclear power plant. Of the many factors involved in the design and layout, this research will cover feed water system layout and optimization issues. The research is arranged in hopes that it can be generalized to any Generation IV system which uses a steam powered turbo-generation unit. The research is done using the ORCENT-II heat balance codes and the Salisbury methodology to be reviewed herein. The Salisbury methodology is used on an original cycle design by Famiani for the Westinghouse IRIS and the effects due to parameter variation are studied. The vital parameters of the Salisbury methodology are the incremental heater surface capital cost (S) in $/ft{sup 2}, the value of incremental power (I) in $/kW, and the overall heat transfer coefficient (U) in Btu/ft{sup 2}-degrees Fahrenheit-hr. Each is varied in order to determine the effects on the cycles overall heat rate, output, as well as, the heater surface areas. The effects of each are shown. Then the methodology is then used to compare the optimized original Famiani design consisting of seven regenerative feedwater heaters with an optimized new cycle concept, INRC8, containing four regenerative heaters. The results are shown. It can be seen that a trade between the complexity of the seven stage regenerative Famiani cycle and the simplicity of the INRC8 cycle can be made. It is desired that this methodology can be used to show the ability to evaluate modularity through the value of size a complexity of the system as well as the performance. It also shows the effectiveness of the Salisbury methodology in the optimization of regenerative cycles for such an evaluation.

  9. Solvent Immersion Imprint Lithography

    SciTech Connect

    Vasdekis, Andreas E.; Wilkins, Michael J.; Grate, Jay W.; Kelly, Ryan T.; Konopka, Allan; Xantheas, Sotiris S.; Chang, M. T.

    2014-06-21

    The mechanism of polymer disolution was explored for polymer microsystem prototyping, including microfluidics and optofluidics. Polymer films are immersed in a solvent, imprinted and finally brought into contact with a non-modified surface to permanently bond. The underlying polymer-solvent interactions were experimentally and theoretically investigated, and enabled rapid polymer microsystem prototyping. During imprinting, small molecule integration in the molded surfaces was feasible, a principle applied to oxygen sensing. Polystyrene (PS) was employed for microbiological studies at extreme environmental conditions. The thermophile anaerobe Clostridium Thermocellum was grown in PS pore-scale micromodels, revealing a double mean generation lifetime than under ideal culture conditions. Microsystem prototyping through directed polymer dissolution is simple and accessible, while simultaneous patterning, bonding, and surface/volume functionalization are possible in less than one minute.

  10. Hybrid Helmet Cure Cycle Optimization

    DTIC Science & Technology

    2008-02-01

    Distribution List 11 iv List of Figures Figure 1. DSC scans of cured and uncured carbon fiber-epoxy prepreg ...thermoplastic fabrics, molded with thermoset prepregs was designed at ARL. Proposed manufacturing of the helmet involved pressure molding a number...of plies of aramid fabric with a thermoplastic film, and two plies of carbon fiber-epoxy prepreg , BT250-E (Bryte Technologies, Inc.) that would add

  11. PARIS II: DESIGNING GREENER SOLVENTS

    EPA Science Inventory

    PARIS II (the program for assisting the replacement of industrial solvents, version II), developed at the USEPA, is a unique software tool that can be used for customizing the design of replacement solvents and for the formulation of new solvents. This program helps users avoid ...

  12. Hazardous solvent substitution

    SciTech Connect

    Twitchell, K.E.

    1995-11-01

    Eliminating hazardous solvents is good for the environment, worker safety, and the bottom line. However, even though we are motivated to find replacements, the big question is `What can we use as replacements for hazardous solvents?`You, too, can find replacements for your hazardous solvents. All you have to do is search for them. Search through the vendor literature of hundreds of companies with thousands of products. Ponder the associated material safety data sheets, assuming of course that you can obtain them and, having obtained them, that you can read them. You will want to search the trade magazines and other sources for product reviews. You will want to talk to users about how well the product actually works. You may also want to check US Environmental Protection Agency (EPA) and other government reports for toxicity and other safety information. And, of course, you will want to compare the product`s constituent chemicals with the many hazardous constituency lists to ensure the safe and legal use of the product in your workplace.

  13. Green Solvents for Precision Cleaning

    NASA Technical Reports Server (NTRS)

    Grandelli, Heather; Maloney, Phillip; DeVor, Robert; Surma, Jan; Hintze, Paul

    2013-01-01

    Aerospace machinery used in liquid oxygen (LOX) fuel systems must be precision cleaned to achieve a very low level of non-volatile residue (< 1 mg0.1 m2), especially flammable residue. Traditionally chlorofluorocarbons (CFCs) have been used in the precision cleaning of LOX systems, specifically CFC 113 (C2Cl3F3). CFCs have been known to cause the depletion of ozone and in 1987, were banned by the Montreal Protocol due to health, safety and environmental concerns. This has now led to the development of new processes in the precision cleaning of aerospace components. An ideal solvent-replacement is non-flammable, environmentally benign, non-corrosive, inexpensive, effective and evaporates completely, leaving no residue. Highlighted is a green precision cleaning process, which is contaminant removal using supercritical carbon dioxide as the environmentally benign solvent. In this process, the contaminant is dissolved in carbon dioxide, and the parts are recovered at the end of the cleaning process completely dry and ready for use. Typical contaminants of aerospace components include hydrocarbon greases, hydraulic fluids, silicone fluids and greases, fluorocarbon fluids and greases and fingerprint oil. Metallic aerospace components range from small nuts and bolts to much larger parts, such as butterfly valves 18 in diameter. A fluorinated grease, Krytox, is investigated as a model contaminant in these preliminary studies, and aluminum coupons are employed as a model aerospace component. Preliminary studies are presented in which the experimental parameters are optimized for removal of Krytox from aluminum coupons in a stirred-batch process. The experimental conditions investigated are temperature, pressure, exposure time and impeller speed. Temperatures of 308 - 423 K, pressures in the range of 8.3 - 41.4 MPa, exposure times between 5 - 60 min and impeller speeds of 0 - 1000 rpm were investigated. Preliminary results showed up to 86 cleaning efficiency with the

  14. SOLVENT FIRE BY-PRODUCTS

    SciTech Connect

    Walker, D; Samuel Fink, S

    2006-05-22

    Southwest Research Institute (SwRI) conducted a burn test of the Caustic-Side Solvent Extraction (CSSX) solvent to determine the combustion products. The testing showed hydrogen fluoride gas is not a combustion product from a solvent fire when up to 70% of the solvent is consumed. The absence of HF in the combustion gases may reflect concentration of the modifier containing the fluoride groups in the unburned portion. SwRI reported results for other gases (CO, HCN, NOx, formaldehyde, and hydrocarbons). The results, with other supporting information, can be used for evaluating the consequences of a facility fire involving the CSSX solvent inventory.

  15. Rigorous Kinetic Modeling and Optimization Study of a Modified Claus Unit for an Integrated Gasification Combined Cycle (IGCC) Power Plant with CO{sub 2} Capture

    SciTech Connect

    Jones, Dustin; Bhattacharyya, Debangsu; Turton, Richard; Zitney, Stephen E.

    2012-02-08

    The modified Claus process is one of the most common technologies for sulfur recovery from acid gas streams. Important design criteria for the Claus unit, when part of an Integrated Gasification Combined Cycle (IGCC) power plant, are the ability to destroy ammonia completely and the ability to recover sulfur thoroughly from a relatively low purity acid gas stream without sacrificing flame stability. Because of these criteria, modifications to the conventional process are often required, resulting in a modified Claus process. For the studies discussed here, these modifications include the use of a 95% pure oxygen stream as the oxidant, a split flow configuration, and the preheating of the feeds with the intermediate pressure steam generated in the waste heat boiler (WHB). In the future, for IGCC plants with CO{sub 2} capture, the Claus unit must satisfy emission standards without sacrificing the plant efficiency in the face of typical disturbances of an IGCC plant, such as rapid change in the feed flow rates due to load-following and wide changes in the feed composition because of changes in the coal feed to the gasifier. The Claus unit should be adequately designed and efficiently operated to satisfy these objectives. Even though the Claus process has been commercialized for decades, most papers concerned with the modeling of the Claus process treat the key reactions as equilibrium reactions. Such models are validated by manipulating the temperature approach to equilibrium for a set of steady-state operating data, but they are of limited use for dynamic studies. One of the objectives of this study is to develop a model that can be used for dynamic studies. In a Claus process, especially in the furnace and the WHB, many reactions may take place. In this work, a set of linearly independent reactions has been identified, and kinetic models of the furnace flame and anoxic zones, WHB, and catalytic reactors have been developed. To facilitate the modeling of the Claus

  16. Rigorous Kinetic Modeling, Optimization, and Operability Studies of a Modified Claus Unit for an Integrated Gasification Combined Cycle (IGCC) Power Plant with CO{sub 2} Capture

    SciTech Connect

    Jones, Dustin; Bhattacharyya, Debangsu; Turton, Richard; Zitney, Stephen E

    2011-12-15

    The modified Claus process is one of the most common technologies for sulfur recovery from acid gas streams. Important design criteria for the Claus unit, when part of an Integrated Gasification Combined Cycle (IGCC) power plant, are the ability to destroy ammonia completely and the ability to recover sulfur thoroughly from a relatively low purity acid gas stream without sacrificing flame stability. Because of these criteria, modifications to the conventional process are often required, resulting in a modified Claus process. For the studies discussed here, these modifications include the use of a 95% pure oxygen stream as the oxidant, a split flow configuration, and the preheating of the feeds with the intermediate pressure steam generated in the waste heat boiler (WHB). In the future, for IGCC plants with CO{sub 2} capture, the Claus unit must satisfy emission standards without sacrificing the plant efficiency in the face of typical disturbances of an IGCC plant, such as rapid change in the feed flow rates due to load-following and wide changes in the feed composition because of changes in the coal feed to the gasifier. The Claus unit should be adequately designed and efficiently operated to satisfy these objectives. Even though the Claus process has been commercialized for decades, most papers concerned with the modeling of the Claus process treat the key reactions as equilibrium reactions. Such models are validated by manipulating the temperature approach to equilibrium for a set of steady-state operating data, but they are of limited use for dynamic studies. One of the objectives of this study is to develop a model that can be used for dynamic studies. In a Claus process, especially in the furnace and the WHB, many reactions may take place. In this work, a set of linearly independent reactions has been identified, and kinetic models of the furnace flame and anoxic zones, WHB, and catalytic reactors have been developed. To facilitate the modeling of the Claus

  17. Selecting water-alcohol mixed solvent for synthesis of polydopamine nano-spheres using solubility parameter

    PubMed Central

    Jiang, Xiaoli; Wang, Yinling; Li, Maoguo

    2014-01-01

    The solvent plays an important role in a given chemical reaction. Since most reaction in nature occur in the mixed-solvent systems, a comprehensive principle for solvent optimization was required. By calculating the Hansen solubility parameters (HSP) distance Ra, we designed a model experiment to explore the influence of mixed solvents on the chemical synthesis. The synthesis of polydopamine (PDA) in the water-alcohol system was chosen as model. As predicted, the well-dispersed PDA spheres were obtained in selected solvents with smaller Ra values: methanol/water, ethanol/water and 2-propanol/water. In addition, the mixed solvent with smaller Ravalues gave a higher conversion of dopamine. The strategy for mixed solvent selection is might be useful to choose optimal reaction media for efficient chemical synthesis. PMID:25317902

  18. Selecting water-alcohol mixed solvent for synthesis of polydopamine nano-spheres using solubility parameter

    NASA Astrophysics Data System (ADS)

    Jiang, Xiaoli; Wang, Yinling; Li, Maoguo

    2014-08-01

    The solvent plays an important role in a given chemical reaction. Since most reaction in nature occur in the mixed-solvent systems, a comprehensive principle for solvent optimization was required. By calculating the Hansen solubility parameters (HSP) distance Ra, we designed a model experiment to explore the influence of mixed solvents on the chemical synthesis. The synthesis of polydopamine (PDA) in the water-alcohol system was chosen as model. As predicted, the well-dispersed PDA spheres were obtained in selected solvents with smaller Ra values: methanol/water, ethanol/water and 2-propanol/water. In addition, the mixed solvent with smaller Ra values gave a higher conversion of dopamine. The strategy for mixed solvent selection is might be useful to choose optimal reaction media for efficient chemical synthesis.

  19. Selecting water-alcohol mixed solvent for synthesis of polydopamine nano-spheres using solubility parameter.

    PubMed

    Jiang, Xiaoli; Wang, Yinling; Li, Maoguo

    2014-08-14

    The solvent plays an important role in a given chemical reaction. Since most reaction in nature occur in the mixed-solvent systems, a comprehensive principle for solvent optimization was required. By calculating the Hansen solubility parameters (HSP) distance Ra, we designed a model experiment to explore the influence of mixed solvents on the chemical synthesis. The synthesis of polydopamine (PDA) in the water-alcohol system was chosen as model. As predicted, the well-dispersed PDA spheres were obtained in selected solvents with smaller Ra values: methanol/water, ethanol/water and 2-propanol/water. In addition, the mixed solvent with smaller Ra values gave a higher conversion of dopamine. The strategy for mixed solvent selection is might be useful to choose optimal reaction media for efficient chemical synthesis.

  20. Solvent Fractionation of Lignin

    SciTech Connect

    Chatterjee, Sabornie; Saito, Tomonori

    2014-01-01

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. The major issues for the commercial production of value added high performance lignin products are lignin s physical and chemical heterogenities. To overcome these problems, a variety of procedures have been developed to produce pure lignin suitable for high performace applications such as lignin-derived carbon materials. However, most of the isolation procedures affect lignin s properties and structure. In this chapter, a short review of the effect of solvent fractionation on lignin s properties and structure is presented.

  1. EVALUATING THE GREENNESS OF IONIC LIQUIDS VIA LIFE CYCLE ASSESSMENT

    EPA Science Inventory

    Ionic Liquids have been suggested as "greener" replacements to traditional solvents. However, the environmental impacts of the life cycle phases have not been studied. Such a "cradle to gate" Life Cycle Assessment (LCA) for comparing the environmental impact of various solvents...

  2. Reversible Tailoring of Mechanical Properties of Carbon Nanotube Forests by Immersing in Solvents

    DTIC Science & Technology

    2014-12-07

    Author’s personal copy Reversible tailoring of mechanical properties of carbon nanotube forests by immersing in solvents Parisa Pour Shahid Saeed...December 2013 Available online 7 December 2013 A B S T R A C T The mechanical behavior of carbon nanotube (CNT) forests soaked in three solvents – tol- uene...solvents, produces the lowest vdW forces between individual CNTs. Furthermore, wet–dry cycling of CNT forests shows the revers- ibility and

  3. Solvent Blending Strategy to Upgrade MCU CSSX Solvent to Equivalent Next-Generation CSSX Solvent

    SciTech Connect

    Delmau, Laetitia Helene; Moyer, Bruce A

    2012-12-01

    The results of the present study have validated an equal-volume blending strategy for upgrading freshly prepared CSSX solvent to a blended solvent functionally equivalent to NG-CSSX solvent. It is shown that blending fresh CSSX solvent as currently used in MCU with an equal volume of an NG-CSSX solvent concentrate of appropriate composition yields a blended solvent composition (46.5 mM of MaxCalix, 3.5 mM of BOBCalixC6, 0.5 M of Cs-7SB, 3 mM of guanidine suppressor, and 1.5 mM of TOA in Isopar L) that exhibits equivalent batch ESS performance to that of the NG-CSSX solvent containing 50 mM of MaxCalix, 0.5 M of Cs-7SB, and 3 mM of guanidine suppressor in Isopar L. The solvent blend composition is robust to third-phase formation. Results also show that a blend containing up to 60% v/v of CSSX solvent could be accommodated with minimal risk. Extraction and density data for the effect of solvent concentration mimicking diluent evaporation or over-dilution of the equal-volume blended solvent are also given, providing input for setting operational limits. Given that the experiments employed all pristine chemicals, the results do not qualify a blended solvent starting with actual used MCU solvent, which can be expected to have undergone some degree of degradation. Consequently, further work should be considered to evaluate this risk and implement appropriate remediation if needed.

  4. Intelligent Space Tube Optimization for speeding ground water remedial design.

    PubMed

    Kalwij, Ineke M; Peralta, Richard C

    2008-01-01

    An innovative Intelligent Space Tube Optimization (ISTO) two-stage approach facilitates solving complex nonlinear flow and contaminant transport management problems. It reduces computational effort of designing optimal ground water remediation systems and strategies for an assumed set of wells. ISTO's stage 1 defines an adaptive mobile space tube that lengthens toward the optimal solution. The space tube has overlapping multidimensional subspaces. Stage 1 generates several strategies within the space tube, trains neural surrogate simulators (NSS) using the limited space tube data, and optimizes using an advanced genetic algorithm (AGA) with NSS. Stage 1 speeds evaluating assumed well locations and combinations. For a large complex plume of solvents and explosives, ISTO stage 1 reaches within 10% of the optimal solution 25% faster than an efficient AGA coupled with comprehensive tabu search (AGCT) does by itself. ISTO input parameters include space tube radius and number of strategies used to train NSS per cycle. Larger radii can speed convergence to optimality for optimizations that achieve it but might increase the number of optimizations reaching it. ISTO stage 2 automatically refines the NSS-AGA stage 1 optimal strategy using heuristic optimization (we used AGCT), without using NSS surrogates. Stage 2 explores the entire solution space. ISTO is applicable for many heuristic optimization settings in which the numerical simulator is computationally intensive, and one would like to reduce that burden.

  5. Comments on "Entransy analysis and optimization of performance of nano-scale irreversible Otto cycle operating with Maxwell-Boltzmann ideal gas"

    NASA Astrophysics Data System (ADS)

    Awad, M. M.

    2017-03-01

    The purpose of this discussion is to increase the awareness of the divergent views on the entransy concept among the readers of chemical physics. Comments are presented in particular on the paper by Ahmadi et al. (2016) where the authors used entransy dissipation in their analysis. Based on the view points of independent different groups of researchers world wide, I draw the attention of readers to the reality that entransy has no physical meaning. In this study, comments on the entransy, and in particular on the paper by Ahmadi et al. [1], are presented to increase the awareness of the divergent views on the entransy concept among the readers of chemical physics. Details of these comments are given below. Ahmadi et al. [1] applied the entransy analysis on the nano scale irreversible Otto cycle. The researchers considered five separate variables including compression process efficiency (ηC), the pressure ratio (x), expansion process efficiency (ηE), temperature of state point 1 (T1) and temperature of state point 3 (T3), as the decision parameters to assess the dimensionless ecological function, the dimensionless entransy dissipation, the ecological coefficient of performance and the energy efficiency of the nano scale irreversible Otto cycle executing thermodynamic analysis. During their analysis, they used entransy dissipation. It is well known that entransy dissipation analysis is a duplicate of entropy generation analysis as shown by Grazzini et al. [2]. Also, Lucia [3] showed that there is a link between the entropy generation and the entransy dissipation, underlining that the two approaches are similar. In addition, Bejan [4] showed that entransy dissipation is a number proportional to well known measures of irreversibility like lost exergy (destroyed available work) and entropy generation. Furthermore, Awad [5] mentioned that irreversibility (entropy generation, or exergy destruction) is a universal tendency in nature that is recognized as the second law

  6. Solvents and supporting electrolytes for vanadium acetylacetonate flow batteries

    NASA Astrophysics Data System (ADS)

    Shinkle, Aaron A.; Pomaville, Timothy J.; Sleightholme, Alice E. S.; Thompson, Levi T.; Monroe, Charles W.

    2014-02-01

    Properties of supporting electrolytes and solvents were examined for use with vanadium acetylacetonate - a member of the class of metal(β-diketonate) active species - in non-aqueous redox flow batteries. Twenty supporting-electrolyte/solvent combinations were screened for ionic conductivity and supporting-electrolyte solubility. Hexane, tetrahydrofuran, and dimethylcarbonate solvents did not meet minimal conductivity and solubility criteria for any of the electrolytes used, which included tetraethylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, and (1-butyl, 3-methyl)imidazolium bis(trifluoromethanesulfonyl)imide. Ionic conductivities and solubilities for solutions of these electrolytes passed screening criteria in acetonitrile and dimethylformamide solvents, in which maximum supporting-electrolyte and active-species solubilities were determined. Active-species electrochemistry was found to be reversible in several solvent/support systems; for some systems the voltammetric signatures of unwanted side reactions were suppressed. Correlations between supporting-solution properties and performance metrics suggest that an optimal solvent for a vanadium acetylacetonate RFB should have a low solvent molar volume for active-species solubility, and a high Hansen polarity for conductivity.

  7. ANALYSIS OF SOLVENT RECOVERED FROM WRIGHT INDUSTRIES, INCORPORATED TESTING

    SciTech Connect

    Poirier, M; Thomas Peters, T; Fernando Fondeur, F; Samuel Fink, S

    2007-01-11

    dispersion benefit. (3) WII Solvent that underwent a cleaning cycle provides an acceptable set of cesium distribution (i.e., D) values when used in a standard Extraction, Scrub, and Strip (ESS) test.

  8. Femtosecond transient dichroism/birefringence studies of solute- solvent friction and solvent dynamics

    SciTech Connect

    Chang, Y.J.; Castner, E.W. Jr.; Konitsky, W.; Waldeck, D.H.

    1994-02-01

    Ultrafast, heterodyne, polarization spectroscopies are used to measure solute-solvent frictional coupling and characterize the neat solvent`s relaxation dynamics on femtosecond and picosecond timescales.

  9. Ionic liquids as novel solvents for the synthesis of sugar fatty acid ester.

    PubMed

    Mai, Ngoc Lan; Ahn, Kihun; Bae, Sang Woo; Shin, Dong Woo; Morya, Vivek Kumar; Koo, Yoon-Mo

    2014-12-01

    Sugar fatty acid esters are bio-surfactants known for their non-toxic, non-ionic, and high biodegradability . With great emulsifying and conditioning effects, sugar fatty acids are widely used in the food, pharmaceutical, and cosmetic industries. Biosynthesis of sugar fatty acid esters has attracted growing attention in recent decades. In this study, the enzymatic synthesis of sugar fatty acid esters in ionic liquids was developed, optimized, and scaled up. Reaction parameters affecting the conversion yield of lipase-catalyzed synthesis of glucose laurate from glucose and vinyl laurate (i.e. temperature, vinyl laurate/glucose molar ratio, and enzyme loads) were optimized by response surface methodology (RSM). In addition, production was scaled up to 2.5 L, and recycling of enzyme and ionic liquids was investigated. The results showed that under optimal reaction conditions (66.86 °C, vinyl laurate/glucose molar ratio of 7.63, enzyme load of 73.33 g/L), an experimental conversion yield of 96.4% was obtained which is close to the optimal value predicted by RSM (97.16%). A similar conversion yield was maintained when the reaction was carried out at 2.5 L. Moreover, the enzymes and ionic liquids could be recycled and reused effectively for up to 10 cycles. The results indicate the feasibility of ionic liquids as novel solvents for the biosynthesis of sugar fatty acid esters.

  10. SOLVENT EXTRACTION OF URANIUM VALUES

    DOEpatents

    Feder, H.M.; Ader, M.; Ross, L.E.

    1959-02-01

    A process is presented for extracting uranium salt from aqueous acidic solutions by organic solvent extraction. It consists in contacting the uranium bearing solution with a water immiscible dialkylacetamide having at least 8 carbon atoms in the molecule. Mentioned as a preferred extractant is dibutylacetamide. The organic solvent is usually used with a diluent such as kerosene or CCl/sub 4/.

  11. Supercritical multicomponent solvent coal extraction

    NASA Technical Reports Server (NTRS)

    Corcoran, W. H.; Fong, W. S.; Pichaichanarong, P.; Chan, P. C. F.; Lawson, D. D. (Inventor)

    1983-01-01

    The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.

  12. Switchable Polarity Solvents: Are They Green?

    NASA Astrophysics Data System (ADS)

    Plaumann, Heinz

    2017-03-01

    Solvents play an incredibly important role in large scale chemical reactions. Switchable polarity solvents may prove to be a class of solvent that offers energy and material efficiencies greater than existing solvents. This paper examines such solvents and their potential in a variety of chemical reactions.

  13. COMPUTER AIDED SOLVENT DESIGN FOR THE ENVIRONMENT

    EPA Science Inventory

    Solvent substitution is an effective and useful means of eliminating the use of harmful solvents, but finding substitute solvents which are less harmful and as effective as currently used solvents presents significant difficulties. Solvent substitution is a form of reverse engin...

  14. Optimize acid gas removal

    SciTech Connect

    Nicholas, D.M.; Wilkins, J.T.

    1983-09-01

    Innovative design of physical solvent plants for acid gas removal can materially reduce both installation and operating costs. A review of the design considerations for one physical solvent process (Selexol) points to numerous arrangements for potential improvement. These are evaluated for a specific case in four combinations that identify an optimum for the case in question but, more importantly, illustrate the mechanism for use for such optimization elsewhere.

  15. Investigation of solvent annealing time dependence on morphology formation in polystyrene-block-polylactide thin films

    NASA Astrophysics Data System (ADS)

    Gnabasik, Ryan; Nelson, Gunnar; Baruth, Andrew

    2015-03-01

    Solvent vapor annealing exposes a block polymer film to the vapors of one or more solvents, swelling the film. This process increases polymer mobility and can direct a self-assembly process by tuning the surface energy. Despite its efficacy to produce well-ordered, periodic nanostructures, no standardized production scheme exists. This is primarily due to a lack of understanding the intricate role multiple, incommensurate parameters play. By analogy to thermal annealing of elemental solids, the time a thin film spends in an equilibrium solvent concentration is one factor that will dictate the degree of ordering. To elucidate, optimized annealing conditions for perpendicular cylinder forming polystyrene-block-polylactide exist at solvent concentrations just below the order-disorder transition, where the kinetic and thermal processes required for recrystallization and crystal growth are optimally fast (similar to thermal annealing). By use of a purpose-built, climate-controlled solvent annealing chamber, we map out the annealing time dependence for non-optimized solvent concentrations. Namely, at lower solvent concentrations, where mobility is limited, longer times are required for large lateral correlation lengths. In situ spectral reflectance monitors solvent concentration, regulated viaa mass-flow controlled solvent inlet, offering precision control over annealing. Atomic force microscopy, in conjunction with O2 plasma etching, provides 3-dimensional imaging of the nanoscale morphology. This work was funded by NASA Nebraska Space Grant.

  16. Carbon Coated SnS/SnO2 Heterostructures Wrapping on CNFs as an Improved-Performance Anode for Li-Ion Batteries: Lithiation-Induced Structural Optimization upon Cycling.

    PubMed

    Lian, Qingwang; Zhou, Gang; Zeng, Xiaohui; Wu, Chen; Wei, Yuehua; Cui, Chao; Wei, Weifeng; Chen, Libao; Li, Chengchao

    2016-11-09

    Carbon coated SnS/SnO2 heterostructures wrapping on carbon nanofibers (C@SnS/SnO2@CNFs) was demonstrated to have excellent performance as an anode material for Li-ion batteries. C@SnS/SnO2@CNFs electrode delivers high reversible capacity of 826.8 mA h g(-1) (500th cycle) at the current density of 1.0 A g(-1). However, an interesting phenomenon of increasing capacity on cycling can be observed. According to the analysis of the evolution of structure and electrochemical property, C@SnS/SnO2@CNFs is demonstrated to experience the progress of conversion from nanowalls containing polycrystals into amorphous nanosheets with high porosity and larger surface upon cycling. The above lithiation-induced structural optimization provides larger effective surface areas and encourages the conversion reactions, which can promote charge transfer and also enhance the reversibility of the conversion reactions of SnS and SnO2 inducing the increasing reversible capacity. The study explains the progress of increasing capacity of C@SnS/SnO2@CNFs and likewise provides a perspective on optimization of the electrochemical performance of electrodes.

  17. Solvent extraction of lubricating oils

    SciTech Connect

    Sequeira, A. Jr.

    1991-08-13

    This patent describes improvement in a process for solvent refining a hydrocarbon based lubricating oil stock containing aromatics and non-aromatics components with an extraction solvent wherein the lubricating oil stock is contacted with the extraction solvent in a first extraction zone at a first extraction temperature in the range of 100{degrees} F to 250{degrees} F and a solvent to oil dosage in the range of 75 to 500 vol % forming an aromatics-rich primary extract and an aromatics-lean primary raffinate of high viscosity index of at least 85. The improvement comprises: withdrawing and cooling the primary extract to a temperature 10{degrees} F to 120{degrees} F below the extraction temperature and admixing with 0.0 vol % to 10 vol % anti-solvent thereby forming a secondary extract and a secondary raffinate, passing the secondary raffinate to a second extraction zone wherein the secondary raffinate is contacted with the extraction solvent at a second extraction temperature in the range of 100{degrees} F to 250{degrees} F and solvent to oil dosage in the range of 75 to 500 vol %, to form an aromatics-lean tertiary raffinate phase of viscosity index 65 or greater.

  18. Influence of solvents on species crossover and capacity decay in non-aqueous vanadium redox flow batteries: Characterization of acetonitrile and 1, 3 dioxolane solvent mixture

    NASA Astrophysics Data System (ADS)

    Bamgbopa, Musbaudeen O.; Almheiri, Saif

    2017-02-01

    The importance of the choice of solvent in a non-aqueous redox flow battery (NARFB) cannot be overemphasized. Several studies demonstrated the influence of the solvent on electrolyte performance in terms of reaction rates, energy/power densities, and efficiencies. In this work, we investigate capacity decay as a direct consequence of varying reactant crossover rates through membranes in different solvent environments. Specifically, we demonstrate the superiority of an 84/16 vol% acetonitrile/1,3 dioxolane solvent mixture over pure acetonitrile in terms of energy efficiency (up to 89%) and capacity retention for vanadium NARFBs - while incorporating a Nafion 115 membrane. The permeability of Nafion to the vanadium acetylacetonate active species is an order of magnitude lower when pure acetonitrile is replaced by the solvent mixture. A method to estimate relative membrane permeability is formulated from numerical analysis of self-discharge experimental data. Furthermore, tests on a modified Nafion/SiO2 membrane, which generally offered low species permeability, also show that different solvents alter membrane permeability. Elemental and morphological analyses of cycled Nafion and NafionSi membranes in different solvent environments indicate that different crossover rates induced by the choice of solvent during cycling are due to changes in the membrane microstructure, intrinsic permeability, swelling rates, and chemical stability.

  19. Swelling of lignites in organic solvents

    SciTech Connect

    R.G. Makitra; D.V. Bryk

    2008-10-15

    Data on the swelling of Turkish lignites can be summarized using linear multiparameter equations that take into account various properties of solvents. Factors responsible for the amounts of absorbed solvents are the basicity and cohesion energy density of the solvents.

  20. Impact of Solvents Treatment on the Wettability of Froth Solids

    NASA Astrophysics Data System (ADS)

    Yang, Fan

    The purpose of this study is to investigate the impact of solvent addition to bitumen froth on the wettability of froth solids. The wettability of solids determines the transportation/partitioning of the solids between phases, which in turn affects the solids and water rejection in a Clark hot water extraction process (CHWE). The impact of solvents treatment on the wettability of froth solids was studied using both a model system and a real bitumen froth system. The vulnerabilities of four kinds of model minerals to hydrocarbon contamination/wettability alteration in different solvents were compared and discussed by considering solvent composition and mineral types. The wettability of solids extracted from the industrial froth using different solvents was also compared. The XRD analysis on these solids confirmed the partitioning behavior of solids observed in model solids system. The results from this study indicate that the composition of paraffinic/aromatic solvent in an industrial froth treatment process could be tailor-optimized to achieve a better solids/water rejection.

  1. ON-SITE SOLVENT RECOVERY

    EPA Science Inventory

    This study evaluated the product quality, waste reduction/pollution prevention, and economic aspects of three technologies for onsite solvent recovery: atmospheric batch distillation, vacuum heat-pump distillation, and low-emission vapor degreasing. The atmospheric and vacuum ...

  2. RESIDUAL RISK ASSESSMENT: HALOGENATED SOLVENTS

    EPA Science Inventory

    This source category previously subjected to a technology-based standard will be examined to determine if health or ecological risks are significant enough to warrant further regulation for Halogenated Solvent Degreasing Facilities. These assessments utilize existing models and d...

  3. SOLV-DB: Solvents Data

    DOE Data Explorer

    SOLV-DB provides a specialized mix of information on commercially available solvents. The development of the database was funded under the Strategic Environmental Research and Development Program (SERDP) with funds from EPA and DOE's Office of Industrial Technologies in EE. The information includes: • Health and safety considerations involved in choosing and using solvents • Chemical and physical data affecting the suitability of a particular solvent for a wide range of potential applications • Regulatory responsibilities, including exposure and effluent limits, hazard classification status with respect to several key statutes, and selected reporting requirements • Environmental fate data, to indicate whether a solvent is likely to break down or persist in air or water, and what types of waste treatment techniques may apply to it • CAS numbers (from Chemical Abstracts Service) and Sax Numbers (from Sax, et.al., Dangerous Properties of Industrial Materials) Supplier Information See help information at http://solvdb.ncms.org/welcome.htm (Specialized Interface)

  4. ICE: Ionic contrast enhancement for organic solvent negative tone develop

    NASA Astrophysics Data System (ADS)

    Sundberg, Linda K.; Wallraff, Gregory M.; Bozano, Luisa D.; Truong, Hoa D.; Sanchez, Martha I.; Goldfarb, Dario L.; Petrillo, Karen E.; Hinsberg, William D.

    2014-03-01

    The use of organic solvents in the development of chemically amplified (CA) resists has been known since the introduction of DUV lithography into manufacturing over twenty years ago [1,2]. In this approach a negative tone image is produced using an aqueous base developable positive tone resist developed in an organic solvent. Recently there has been an increased interest in negative tone imaging due to superior performance for specific masking levels such as narrow trenches and contact holes [3]. Negative tone imaging of this type is based on differences in the polarity between the exposed and unexposed regions of the resist film. The dissolution contrast can be optimized by selecting a solvent with the proper match of solubility parameters (polarity, hydrogen bonding and dispersion) to attain good solubility of the relatively nonpolar unexposed resist and poor solubility of the deprotected acidic exposed film. Another approach is to tune the properties of the resist polymer for a given solvent, creating a new optimized resist. We have explored a third methodology to achieve a high contrast solvent developable system without a need to modify resist or solvent. In this report we describe a process that exploits the differences in solubility between ionic and organic materials. In this method an ionic species is introduced into the resist film following post-exposure bake to alter the polarity in such way that the resist contrast can be improved in organic solvent development. We describe processes using pre-rinses and developers containing salts. Lithographic response, characterized using contrast curves and imaging, is presented for a variety of resist platforms. We show evidence for ionic incorporation into the resist film using SIMS, XPS, QCM and FTIR characterization. We demonstrate the practical applicability of this method to 248nm, 193nm, e-beam and EUV exposures.

  5. TALSPEAK Solvent Degradation

    SciTech Connect

    Leigh R. Martin; Bruce J. Mincher

    2009-09-01

    Understanding the radiolytic degradation behavior of organic molecules involved in new or existing schemes for the recycle of used nuclear fuels is of significant interest for sustaining a closed nuclear fuel cycle. Here we have conducted several lines of investigation to begin understanding the effects of radiolysis on the aqueous phase of the TALSPEAK process for the separation of the trivalent lanthanides from the trivalent actinides. Using the 60-Co irradiator at the INL, we have begun to quantify the effects of radiation on the aqueous phase complexants used in this separation technique, and how this will affect the actinide lanthanide separation factor. In addition we have started to develop methodologies for stable product identification, a key element in determining the degradation pathways. We have also introduced a methodology to investigate the effects of alpha radiolysis that has previously received limited attention.

  6. Applied biotransformations in green solvents.

    PubMed

    Hernáiz, María J; Alcántara, Andrés R; García, José I; Sinisterra, José V

    2010-08-16

    The definite interest in implementing sustainable industrial technologies has impelled the use of biocatalysts (enzymes or cells), leading to high chemo-, regio- and stereoselectivities under mild conditions. As usual substrates are not soluble in water, the employ of organic solvents is mandatory. We will focus on different attempts to combine the valuable properties of green solvents with the advantages of using biocatalysts for developing cleaner synthetic processes.

  7. Recombinant LH supplementation during IVF cycles with a GnRH-antagonist in estimated poor responders: A cross-matched pilot investigation of the optimal daily dose and timing

    PubMed Central

    GIZZO, SALVATORE; ANDRISANI, ALESSANDRA; NOVENTA, MARCO; MANFÈ, SERENA; OLIVA, ALESSANDRA; GANGEMI, MICHELE; NARDELLI, GIOVANNI BATTISTA; AMBROSINI, GUIDO

    2015-01-01

    Although it is widely accepted that patients, who are considered poor responders to in vitro fertilization (IVF) benefit from recombinant luteinizing hormone (rLH) supplementation during an in vitro fertilization cycle, particularly when gonadotropin-releasing hormone (GnRH) antagonist (ant) treatment is used the optimal administration timing and daily dose of rLH remains to be elucidated. The aim of the present study was to investigate the optimal timing of rLH-supplementation to improve ovarian response, embryo quality, endometrial thickness and pregnancy rate in infertile, estimated poor responders to IVF, undergoing GnRH-ant treatment. In addition, the present study aimed to evaluate the optimal daily dose to achieve the same outcomes. A prospective-randomized-cross-matched investigation was performed on 40 patients undergoing a GnRH-ant-treatment-cycle The patients were randomly assigned to either group A (rLH-75 IU/day) or group B (rLH-150 IU/day) and further randomized into subgroup A1/B1, in which rLH was administered at recombinant follicle stimulating hormone (rFSH) administration, and subgroup A2/B2, in which rLH was administered at GnRH-ant administration. Patients who did not become pregnant during the first cycle (35 patients), were treated a second time, cross-matched for groups and subgroups. Improved ovarian response, embryo quality and pregnancy rate were achieved by administering rLH at 150 IU/day, starting from GnRH-ant administration, independently from the total rLH dose administered. Improved endometrial thickness at oocyte retrieval day was achieved by administering rLH at 150 IU from the start of rFSH administration. These data led to the hypothesis that ovarian responses are affected by the timing of administration more than the total-dose of rLH. The optimal window to administer rLH appears to be the mid-to-late follicular phase, despite the fact that rLH-supplementation in the early follicular phase appeared to increase endometrial

  8. Up-cycling waste glass to minimal water adsorption/absorption lightweight aggregate by rapid low temperature sintering: optimization by dual process-mixture response surface methodology.

    PubMed

    Velis, Costas A; Franco-Salinas, Claudia; O'Sullivan, Catherine; Najorka, Jens; Boccaccini, Aldo R; Cheeseman, Christopher R

    2014-07-01

    Mixed color waste glass extracted from municipal solid waste is either not recycled, in which case it is an environmental and financial liability, or it is used in relatively low value applications such as normal weight aggregate. Here, we report on converting it into a novel glass-ceramic lightweight aggregate (LWA), potentially suitable for high added value applications in structural concrete (upcycling). The artificial LWA particles were formed by rapidly sintering (<10 min) waste glass powder with clay mixes using sodium silicate as binder and borate salt as flux. Composition and processing were optimized using response surface methodology (RSM) modeling, and specifically (i) a combined process-mixture dual RSM, and (ii) multiobjective optimization functions. The optimization considered raw materials and energy costs. Mineralogical and physical transformations occur during sintering and a cellular vesicular glass-ceramic composite microstructure is formed, with strong correlations existing between bloating/shrinkage during sintering, density and water adsorption/absorption. The diametrical expansion could be effectively modeled via the RSM and controlled to meet a wide range of specifications; here we optimized for LWA structural concrete. The optimally designed LWA is sintered in comparatively low temperatures (825-835 °C), thus potentially saving costs and lowering emissions; it had exceptionally low water adsorption/absorption (6.1-7.2% w/wd; optimization target: 1.5-7.5% w/wd); while remaining substantially lightweight (density: 1.24-1.28 g.cm(-3); target: 0.9-1.3 g.cm(-3)). This is a considerable advancement for designing effective environmentally friendly lightweight concrete constructions, and boosting resource efficiency of waste glass flows.

  9. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    NASA Technical Reports Server (NTRS)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  10. Computational comparison of oxidation stability: Solvent/salt monomers vs solvent-solvent/salt pairs

    NASA Astrophysics Data System (ADS)

    Kim, Dong Young; Park, Min Sik; Lim, Younhee; Kang, Yoon-Sok; Park, Jin-Hwan; Doo, Seok-Gwang

    2015-08-01

    A fundamental understanding of the anodic stabilities of electrolytes is important for the development of advanced high-voltage electrolytes. In this study, we calculated and systematically compared the oxidation stabilities of monomeric solvents and anions, and bimolecular solvent-solvent and anion-solvent systems that are considered to be high-voltage electrolyte components, using ab initio calculations. Oxidation stabilities of solvent or anion monomers without considering specific solvation molecules cannot represent experimental oxidation stabilities. The oxidation of electrolytes usually forms neutral or cationic radicals, which immediately undergo further reactions stabilizing the products. Oxidatively driven intermolecular reactions are the main reason for the lower oxidation stabilities of electrolytes compared with those of monomeric compounds. Electrolyte components such as tetramethylene sulfone (TMS), ethyl methyl sulfone (EMS), bis(oxalate)borate (BOB-), and bis(trifluoromethane)sulfonamide (TFSI-) that minimize such intermolecular chemical reactions on oxidation can maintain the oxidation stabilities of monomers. In predictions of the theoretical oxidation stabilities of electrolytes, simple comparisons of highest occupied molecular orbital energies can be misleading, even if microsolvation or bulk clusters are considered. Instead, bimolecular solvent complexes with a salt anion should be at least considered in oxidation calculations. This study provides important information on fundamental and applied aspects of the development of electrolytes.

  11. Menstrual Cycle

    MedlinePlus

    ... receive Pregnancy email updates Enter email Submit The menstrual cycle Day 1 starts with the first day of ... drop around Day 25 . This signals the next menstrual cycle to begin. The egg will break apart and ...

  12. Development of India-specific RAFM steel through optimization of tungsten and tantalum contents for better combination of impact, tensile, low cycle fatigue and creep properties

    NASA Astrophysics Data System (ADS)

    Laha, K.; Saroja, S.; Moitra, A.; Sandhya, R.; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

    2013-08-01

    Effects of tungsten and tantalum contents on impact, tensile, low cycle fatigue and creep properties of Reduced Activation Ferritic-Martensitic (RAFM) steel were studied to develop India-specific RAFM steel. Four heats of the steel have been melted with tungsten and tantalum contents in the ranges 1-2 wt.% and 0.06-0.14 wt.% respectively. Increase in tungsten content increased the ductile-to-brittle transition temperature (DBTT), low cycle fatigue and creep strength of the steel, whereas the tensile strength was not changed significantly. Increase in tantalum content increased the DBTT and low cycle fatigue strength of the steel whereas the tensile and creep strength decreased. Detailed TEM investigations revealed enhanced microstructural stability of the steel against creep exposure on tungsten addition. The RAFM steel having 1.4 wt.% tungsten with 0.06 wt.% tantalum was found to possess optimum combination of impact, tensile, low cycle fatigue and creep properties and is considered for Indian-specific RAFM steel. Low temperature impact energy of the RAFM steel is quite sensitive to the contents of tungsten and tantalum. The DBTT increased with both the tungsten and tantalum contents. Tungsten and tantalum contents in the investigated ranges had no appreciable effect on the tensile properties of the RAFM steel. Low cycle fatigue life of the RAFM steel increased with the increase in tungsten and tantalum contents. The softening rate with cyclic exposure was lowest for tungsten content of 1.4 wt.%, further increase in tungsten led to an increase in softening rate. Creep deformation and rupture strength of the RAFM steel were found to be quite sensitive to the tungsten and tantalum contents. Creep strength of the steel increased with increase in tungsten content and decreased with increase in tantalum content. Based on the study, the chemical composition of India-specific RAFM steel has been established as 9Cr-1.4W-0.06Ta-V, having optimum combination of strength and

  13. Coal liquefaction process with enhanced process solvent

    DOEpatents

    Givens, Edwin N.; Kang, Dohee

    1984-01-01

    In an improved coal liquefaction process, including a critical solvent deashing stage, high value product recovery is improved and enhanced process-derived solvent is provided by recycling second separator underflow in the critical solvent deashing stage to the coal slurry mix, for inclusion in the process solvent pool.

  14. Method of treating radioactively contaminated solvent waste

    SciTech Connect

    Jablonski, W.; Mallek, H.; Plum, W.

    1981-07-07

    A method of and apparatus for treating radioactively contaminated solvent waste are claimed. The solvent waste is supplied to material such as peat, vermiculite, diaton, etc. This material effects the distribution or dispersion of the solvent and absorbs the foreign substances found in the solvent waste. Air or an inert gas flows through the material in order to pick up the solvent portions which are volatile as a consequence of their vapor pressure. The thus formed gas mixture, which includes air or inert gas and solvent portions, is purified in a known manner by thermal, electrical, or catalytic combustion of the solvent portions.

  15. Acid Base Titrations in Nonaqueous Solvents and Solvent Mixtures

    NASA Astrophysics Data System (ADS)

    Barcza, Lajos; Buvári-Barcza, Ágnes

    2003-07-01

    The acid base determination of different substances by nonaqueous titrations is highly preferred in pharmaceutical analyses since the method is quantitative, exact, and reproducible. The modern interpretation of the reactions in nonaqueous solvents started in the last century, but several inconsistencies and unsolved problems can be found in the literature. The acid base theories of Brønsted Lowry and Lewis as well as the so-called solvent theory are outlined first, then the promoting (and leveling) and the differentiating effects are discussed on the basis of the hydrogen-bond concept. Emphasis is put on the properties of formic acid and acetic anhydride since their importance is increasing.

  16. DOE solvent handbook information sheet

    SciTech Connect

    Chavez, A.A.

    1992-01-01

    Solvents and cleaners are used in the Department of Defense (DOD) and the Department of Energy-Defense Program (DOE-DP) maintenance facilities for removing wax, grease, oil, carbon, machining fluids, solder fluxes, mold releases, and other contaminants before repairing or electroplating parts. Private industry also uses cleaners and degreasers for surface preparation of various metals. Growing environmental and worker safety concerns have brought attention to these solvents and cleaners, most of which are classified as toxic. Tightening government regulations have already excluded the use of some chemicals, and restrict the use of various halogenated hydrocarbons because of their atmospheric-ozone depleting effects, as well as their cancer-related risks. As a result, a program was established to develop an efficient, easily accessible, electronic solvent utilization handbook. This is being accomplished by: (1) identifying solvents (alternatives) that are not currently restricted by government regulations for use DOE-DP facilities, and private industry, (2) evaluating their cleaning performance, (3) evaluating their corrosivity, (4) evaluating their air emissions, (5) evaluating the possibility of recycling or recovering all or portions of the alternative degreasers, (6) testing substitute solvents compatibility with non-metallic materials, (7) inputting all of the data gathered (including previous biodegradability information) into a database, and (8) developing a methodology for efficient, widespread access to the data base information system.

  17. DOE solvent handbook information sheet

    SciTech Connect

    Chavez, A.A.

    1992-05-01

    Solvents and cleaners are used in the Department of Defense (DOD) and the Department of Energy-Defense Program (DOE-DP) maintenance facilities for removing wax, grease, oil, carbon, machining fluids, solder fluxes, mold releases, and other contaminants before repairing or electroplating parts. Private industry also uses cleaners and degreasers for surface preparation of various metals. Growing environmental and worker safety concerns have brought attention to these solvents and cleaners, most of which are classified as toxic. Tightening government regulations have already excluded the use of some chemicals, and restrict the use of various halogenated hydrocarbons because of their atmospheric-ozone depleting effects, as well as their cancer-related risks. As a result, a program was established to develop an efficient, easily accessible, electronic solvent utilization handbook. This is being accomplished by: (1) identifying solvents (alternatives) that are not currently restricted by government regulations for use DOE-DP facilities, and private industry, (2) evaluating their cleaning performance, (3) evaluating their corrosivity, (4) evaluating their air emissions, (5) evaluating the possibility of recycling or recovering all or portions of the alternative degreasers, (6) testing substitute solvents compatibility with non-metallic materials, (7) inputting all of the data gathered (including previous biodegradability information) into a database, and (8) developing a methodology for efficient, widespread access to the data base information system.

  18. Helpful hints for physical solvent absorption

    SciTech Connect

    Wolfer, W.

    1982-11-01

    Review of experience with natural gas treatment using physical solvents points to design and operating suggestions. Experiences with three plants using either Selexol or Sepasolv MPE solvent shows that both solvents perform well. The solvents offer economical and problem-free purification of natural gas. The Sepasolv MPE and Selexol solvents are very similar in chemical structure and physical properties. Thus, their application range is almost similar. An exchange is possible in most plants without equipment modification and/or process data.

  19. Solvent-regenerated activated carbon

    SciTech Connect

    McLaughlin, H. )

    1988-07-01

    This report summarizes the results of a University/Industry research project, sponsored by the New York State Energy Research and Development Authority and Fluids Design Corporation. The research project studied the solvent regeneration of activated carbon. Activate carbon was used to remove trace organics from aqueous streams, then regenerated by desorbing the adsorbates with organic solvents. The project included a survey of the potential applications in New York State industries, fundamental research on the adsorption/desorption phenomena, and design of a full-scale process. The economics of the full-scale process were evaluated and compared to alternate available technologies. The result of this work is a versatile process with attractive economics. A wide range of adsorbates and solvents were found to be acceptable for this process. The design methodologies are developed and the techniques for evaluating a new application are delineated. 13 refs., 12 figs., 4 tabs.

  20. Refinement of protein structures in explicit solvent.

    PubMed

    Linge, Jens P; Williams, Mark A; Spronk, Christian A E M; Bonvin, Alexandre M J J; Nilges, Michael

    2003-02-15

    We present a CPU efficient protocol for refinement of protein structures in a thin layer of explicit solvent and energy parameters with completely revised dihedral angle terms. Our approach is suitable for protein structures determined by theoretical (e.g., homology modeling or threading) or experimental methods (e.g., NMR). In contrast to other recently proposed refinement protocols, we put a strong emphasis on consistency with widely accepted covalent parameters and computational efficiency. We illustrate the method for NMR structure calculations of three proteins: interleukin-4, ubiquitin, and crambin. We show a comparison of their structure ensembles before and after refinement in water with and without a force field energy term for the dihedral angles; crambin was also refined in DMSO. Our results demonstrate the significant improvement of structure quality by a short refinement in a thin layer of solvent. Further, they show that a dihedral angle energy term in the force field is beneficial for structure calculation and refinement. We discuss the optimal weight for the energy constant for the backbone angle omega and include an extensive discussion of meaning and relevance of the calculated validation criteria, in particular root mean square Z scores for covalent parameters such as bond lengths.

  1. Connecting free energy surfaces in implicit and explicit solvent: an efficient method to compute conformational and solvation free energies.

    PubMed

    Deng, Nanjie; Zhang, Bin W; Levy, Ronald M

    2015-06-09

    The ability to accurately model solvent effects on free energy surfaces is important for understanding many biophysical processes including protein folding and misfolding, allosteric transitions, and protein–ligand binding. Although all-atom simulations in explicit solvent can provide an accurate model for biomolecules in solution, explicit solvent simulations are hampered by the slow equilibration on rugged landscapes containing multiple basins separated by barriers. In many cases, implicit solvent models can be used to significantly speed up the conformational sampling; however, implicit solvent simulations do not fully capture the effects of a molecular solvent, and this can lead to loss of accuracy in the estimated free energies. Here we introduce a new approach to compute free energy changes in which the molecular details of explicit solvent simulations are retained while also taking advantage of the speed of the implicit solvent simulations. In this approach, the slow equilibration in explicit solvent, due to the long waiting times before barrier crossing, is avoided by using a thermodynamic cycle which connects the free energy basins in implicit solvent and explicit solvent using a localized decoupling scheme. We test this method by computing conformational free energy differences and solvation free energies of the model system alanine dipeptide in water. The free energy changes between basins in explicit solvent calculated using fully explicit solvent paths agree with the corresponding free energy differences obtained using the implicit/explicit thermodynamic cycle to within 0.3 kcal/mol out of ∼3 kcal/mol at only ∼8% of the computational cost. We note that WHAM methods can be used to further improve the efficiency and accuracy of the implicit/explicit thermodynamic cycle.

  2. Optimization of the analogue-sensitive Cdc2/Cdk1 mutant by in vivo selection eliminates physiological limitations to its use in cell cycle analysis.

    PubMed

    Aoi, Yuki; Kawashima, Shigehiro A; Simanis, Viesturs; Yamamoto, Masayuki; Sato, Masamitsu

    2014-07-01

    Analogue-sensitive (as) mutants of kinases are widely used to selectively inhibit a single kinase with few off-target effects. The analogue-sensitive mutant cdc2-as of fission yeast (Schizosaccharomyces pombe) is a powerful tool to study the cell cycle, but the strain displays meiotic defects, and is sensitive to high and low temperature even in the absence of ATP-analogue inhibitors. This has limited the use of the strain for use in these settings. Here, we used in vivo selection for intragenic suppressor mutations of cdc2-as that restore full function in the absence of ATP-analogues. The cdc2-asM17 underwent meiosis and produced viable spores to a similar degree to the wild-type strain. The suppressor mutation also rescued the sensitivity of the cdc2-as strain to high and low temperature, genotoxins and an anti-microtubule drug. We have used cdc2-asM17 to show that Cdc2 activity is required to maintain the activity of the spindle assembly checkpoint. Furthermore, we also demonstrate that maintenance of the Shugoshin Sgo1 at meiotic centromeres does not require Cdc2 activity, whereas localization of the kinase aurora does. The modified cdc2-asM17 allele can be thus used to analyse many aspects of cell-cycle-related events in fission yeast.

  3. Controlling successive ionic layer absorption and reaction cycles to optimize silver nanoparticle-induced localized surface plasmon resonance effects on the paper strip

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Chul; Kim, Wansun; Park, Hun-Kuk; Choi, Samjin

    2017-03-01

    This study investigates why a silver nanoparticle (SNP)-induced surface-enhanced Raman scattering (SERS) paper chip fabricated at low successive ionic layer absorption and reaction (SILAR) cycles leads to a high SERS enhancement factor (7 × 108) with an inferior nanostructure and without generating a hot spot effect. The multi-layered structure of SNPs on cellulose fibers, verified by magnified scanning electron microscopy (SEM) and analyzed by a computational simulation method, was hypothesized as the reason. The pattern of simulated local electric field distribution with respect to the number of SILAR cycles showed good agreement with the experimental Raman intensity, regardless of the wavelength of the excitation laser sources. The simulated enhancement factor at the 785-nm excitation laser source (2.8 × 109) was 2.5 times greater than the experimental enhancement factor (1.1 × 109). A 532-nm excitation laser source exhibited the highest maximum local electric field intensity (1.9 × 1011), particularly at the interparticle gap called a hot spot. The short wavelength led to a strong electric field intensity caused by strong electromagnetic coupling arising from the SNP-induced local surface plasmon resonance (LSPR) effects through high excitation energy. These findings suggest that our paper-based SILAR-fabricated SNP-induced LSPR model is valid for understanding SNP-induced LSPR effects.

  4. Controlling successive ionic layer absorption and reaction cycles to optimize silver nanoparticle-induced localized surface plasmon resonance effects on the paper strip.

    PubMed

    Lee, Jae-Chul; Kim, Wansun; Park, Hun-Kuk; Choi, Samjin

    2017-03-05

    This study investigates why a silver nanoparticle (SNP)-induced surface-enhanced Raman scattering (SERS) paper chip fabricated at low successive ionic layer absorption and reaction (SILAR) cycles leads to a high SERS enhancement factor (7×10(8)) with an inferior nanostructure and without generating a hot spot effect. The multi-layered structure of SNPs on cellulose fibers, verified by magnified scanning electron microscopy (SEM) and analyzed by a computational simulation method, was hypothesized as the reason. The pattern of simulated local electric field distribution with respect to the number of SILAR cycles showed good agreement with the experimental Raman intensity, regardless of the wavelength of the excitation laser sources. The simulated enhancement factor at the 785-nm excitation laser source (2.8×10(9)) was 2.5 times greater than the experimental enhancement factor (1.1×10(9)). A 532-nm excitation laser source exhibited the highest maximum local electric field intensity (1.9×10(11)), particularly at the interparticle gap called a hot spot. The short wavelength led to a strong electric field intensity caused by strong electromagnetic coupling arising from the SNP-induced local surface plasmon resonance (LSPR) effects through high excitation energy. These findings suggest that our paper-based SILAR-fabricated SNP-induced LSPR model is valid for understanding SNP-induced LSPR effects.

  5. Solvent reorganization of electron transitions in viscous solvents

    SciTech Connect

    Ghorai, Pradip K.; Matyushov, Dmitry V.

    2006-04-14

    We develop a model of electron transfer reactions at conditions of nonergodicity when the time of solvent relaxation crosses the observation time window set up by the reaction rate. Solvent reorganization energy of intramolecular electron transfer in a charge-transfer molecule dissolved in water and acetonitrile is studied by molecular dynamics simulations at varying temperatures. We observe a sharp decrease of the reorganization energy at a temperature identified as the temperature of structural arrest due to cage effect, as discussed by the mode-coupling theory. This temperature also marks the onset of the enhancement of translational diffusion relative to rotational relaxation signaling the breakdown of the Stokes-Einstein relation. The change in the reorganization energy at the transition temperature reflects the dynamical arrest of the slow, collective relaxation of the solvent related to the relaxation of the solvent dipolar polarization. An analytical theory proposed to describe this effect agrees well with both the simulations and experimental Stokes shift data. The theory is applied to the analysis of charge-transfer kinetics in a low-temperature glass former. We show that the reorganization energy is substantially lower than its equilibrium value for the low-temperature portion of the data. The theory predicts the possibility of discontinuous changes in the dependence of the electron transfer rate on the free energy gap when the reaction switches between ergodic and nonergodic regimes.

  6. Solvent extraction of gold using ionic liquid based process

    NASA Astrophysics Data System (ADS)

    Makertihartha, I. G. B. N.; Zunita, Megawati; Rizki, Z.; Dharmawijaya, P. T.

    2017-01-01

    In decades, many research and mineral processing industries are using solvent extraction technology for metal ions separation. Solvent extraction technique has been used for the purification of precious metals such as Au and Pd, and base metals such as Cu, Zn and Cd. This process uses organic compounds as solvent. Organic solvents have some undesired properties i.e. toxic, volatile, excessive used, flammable, difficult to recycle, low reusability, low Au recovery, together with the problems related to the disposal of spent extractants and diluents, even the costs associated with these processes are relatively expensive. Therefore, a lot of research have boosted into the development of safe and environmentally friendly process for Au separation. Ionic liquids (ILs) are the potential alternative for gold extraction because they possess several desirable properties, such as a the ability to expanse temperature process up to 300°C, good solvent properties for a wide range of metal ions, high selectivity, low vapor pressures, stability up to 200°C, easy preparation, environmentally friendly (commonly called as "green solvent"), and relatively low cost. This review paper is focused in investigate of some ILs that have the potentials as solvent in extraction of Au from mineral/metal alloy at various conditions (pH, temperature, and pressure). Performances of ILs extraction of Au are studied in depth, i.e. structural relationship of ILs with capability to separate Au from metal ions aggregate. Optimal extraction conditon in order to gain high percent of Au in mineral processing is also investigated.

  7. Organic Solvent Effects in Biomass Conversion Reactions.

    PubMed

    Shuai, Li; Luterbacher, Jeremy

    2016-01-01

    Transforming lignocellulosic biomass into fuels and chemicals has been intensely studied in recent years. A large amount of work has been dedicated to finding suitable solvent systems, which can improve the transformation of biomass into value-added chemicals. These efforts have been undertaken based on numerous research results that have shown that organic solvents can improve both conversion and selectivity of biomass to platform molecules. We present an overview of these organic solvent effects, which are harnessed in biomass conversion processes, including conversion of biomass to sugars, conversion of sugars to furanic compounds, and production of lignin monomers. A special emphasis is placed on comparing the solvent effects on conversion and product selectivity in water with those in organic solvents while discussing the origins of the differences that arise. We have categorized results as benefiting from two major types of effects: solvent effects on solubility of biomass components including cellulose and lignin and solvent effects on chemical thermodynamics including those affecting reactants, intermediates, products, and/or catalysts. Finally, the challenges of using organic solvents in industrial processes are discussed from the perspective of solvent cost, solvent stability, and solvent safety. We suggest that a holistic view of solvent effects, the mechanistic elucidation of these effects, and the careful consideration of the challenges associated with solvent use could assist researchers in choosing and designing improved solvent systems for targeted biomass conversion processes.

  8. Risk assessment for halogenated solvents

    SciTech Connect

    Travis, C.C.

    1988-01-01

    A recent development in the cancer risk area is the advent of biologically based pharmacokinetic and pharmacodynamic models. These models allow for the incorporation of biological and mechanistic data into the risk assessment process. These advances will not only improve the risk assessment process for halogenated solvents but will stimulate and guide basic research in the biological area.

  9. Assessment of the impact of the next generation solvent on DWPF melter off-gas flammability

    SciTech Connect

    Daniel, W. E.

    2013-02-13

    An assessment has been made to evaluate the impact on the DWPF melter off-gas flammability of replacing the current solvent used in the Modular Caustic-Side Solvent Extraction Process Unit (MCU) process with the Next Generation Solvent (NGS-MCU) and blended solvent. The results of this study showed that the concentrations of nonvolatile carbon and hydrogen of the current solvent in the Slurry Mix Evaporator (SME) product would both be about 29% higher than their counterparts of the NGS-MCU and blended solvent in the absence of guanidine partitioning. When 6 ppm of guanidine (TiDG) was added to the effluent transfer to DWPF to simulate partitioning for the NGS-MCU and blended solvent cases and the concentration of Isopar{reg_sign} L in the effluent transfer was controlled below 87 ppm, the concentrations of nonvolatile carbon and hydrogen of the NGS-MCU and blended solvent were still about 12% and 4% lower, respectively, than those of the current solvent. It is, therefore, concluded that as long as the volume of MCU effluent transfer to DWPF is limited to 15,000 gallons per Sludge Receipt and Adjustment Tank (SRAT)/SME cycle and the concentration of Isopar{reg_sign} L in the effluent transfer is controlled below 87 ppm, using the current solvent assumption of 105 ppm Isopar{reg_sign} L or 150 ppm solvent in lieu of NGS-MCU or blended solvent in the DWPF melter off-gas flammability assessment is conservative for up to an additional 6 ppm of TiDG in the effluent due to guanidine partitioning. This report documents the calculations performed to reach this conclusion.

  10. Solvent minimization in two-dimensional liquid chromatography.

    PubMed

    Horváth, Krisztián; Sepsey, Annamária; Hajós, Péter

    2015-01-23

    An algorithm was developed for the minimization of consumption of organic solvent in comprehensive two-dimensional liquid chromatography (2DLC). It was shown that one can reach higher peak capacities only by using more eluent. The equilibration volume of the second dimension, however, did not affect the solvent consumption significantly. Calculations confirmed that the same target peak capacity could be achieved by consuming significantly different volume of organic modifier depending on the number of fractions analyzed in the second dimension suggesting that 2D separations can be optimized for eluent consumption. It was shown that minimization of eluent usage requires the use of small and high efficient columns in the second dimension. A simple equation was derived for the calculation of the optimal number of collected fractions from the first dimension that allowed the minimization of eluent usage, cost and environmental impact of comprehensive 2DLC separations.

  11. Replacement solvents for use in chemical synthesis

    DOEpatents

    Molnar, Linda K.; Hatton, T. Alan; Buchwald, Stephen L.

    2001-05-15

    Replacement solvents for use in chemical synthesis include polymer-immobilized solvents having a flexible polymer backbone and a plurality of pendant groups attached onto the polymer backbone, the pendant groups comprising a flexible linking unit bound to the polymer backbone and to a terminal solvating moiety. The polymer-immobilized solvent may be dissolved in a benign medium. Replacement solvents for chemical reactions for which tetrahydrofuran or diethyl may be a solvent include substituted tetrahydrofurfuryl ethers and substituted tetrahydro-3-furan ethers. The replacement solvents may be readily recovered from the reaction train using conventional methods.

  12. Carbon dioxide-based supercritical fluids as IC manufacturing solvents

    SciTech Connect

    Rubin, J.B.; Davenhall, L.B.; Taylor, C.M.V.; Sivils, L.D.; Pierce, T.; Tiefert, K.

    1999-05-11

    The production of integrated circuits (IC's) involves a number of discrete steps which utilize hazardous or regulated solvents and generate large waste streams. ES&H considerations associated with these chemicals have prompted a search for alternative, more environmentally benign solvent systems. An emerging technology for conventional solvent replacement is the use of supercritical fluids based on carbon dioxide (CO{sub 2}). Research work, conducted at Los Alamos in conjunction with the Hewlett-Packard Company, has lead to the development of a CO{sub 2}-based supercritical fluid treatment system for the stripping of hard-baked photoresists. This treatment system, known as Supercritical CO{sub 2} Resist Remover, or CORR, uses a two-component solvent composed of a nonhazardous, non-regulated compound, dissolved in supercritical CO{sub 2}. The solvent/treatment system has been successfully tested on metallized Si wafers coated with negative and positive photoresist, the latter both before and after ion-implantation. A description of the experimental data will be presented. Based on the initial laboratory results, the project has progressed to the design and construction of prototype, single-wafer photoresist-stripping equipment. The integrated system involves a closed-loop, recirculating cycle which continuously cleans and regenerates the CO{sub 2}, recycles the dissolved solvent, and separates and concentrates the spent resist. The status of the current design and implementation strategy of a treatment system to existing IC fabrication facilities will be discussed. Additional remarks will be made on the use of a SCORR-type system for the cleaning of wafers prior to processing.

  13. Modeling Carbon Dioxide Capture by Monoethanolamine Solvent with ASPEN Plus

    NASA Astrophysics Data System (ADS)

    Luo, Tianyi

    Fossil fuels provide approximately 80% of the world's energy demands. Methods for reducing CO2 emissions resulting from fossil fuels include increasing the efficiency of power plants and production processes, decreasing energy demands, in combination with CO2 capture and long term storage (CCS). CO2 capture technologies include post-combustion, pre-combustion, and oxyfuel combustion. The amine-based post-combustion CO2 capture from a coal-fired power plant was studied in this thesis. In case of post-combustion capture, CO2 can be captured by Monoethanolamine solvent (MEA), a primary ethanolamine. MEA can associate with H3O+ to form an ion MEAH+, and can react with CO2 to form a carbonate ion MEACOO-. Commercial code ASPEN Plus was used to simulate the process of CO2 capture and optimize the process parameters and required energy duty. The major part of thermal energy requirement is from the Absorber and Stripper columns. This suggests that process optimization should focus on the Absorption/Desorption process. Optimization results show that the gas-liquid reaction equilibrium is affected by several operating parameters including solvent flow rate, stream temperature, column operating pressure, flue gas composition, solvent concentration and absorber design. With optimized CO2 capture, the energy consumption for solvent regeneration (reboiler thermal duty) was decreased from 5.76 GJ/ton captured CO2 to 4.56 GJ/t CO2. On the other hand, the cost of CO2 capture (and sequestration) could be reduced by limiting size of the Absorber column and operating pressure.

  14. Global water cycle

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin R.; Christy, John R.; Goodman, Steven J.; Miller, Tim L.; Fitzjarrald, Dan; Lapenta, Bill; Wang, Shouping

    1991-01-01

    The primary objective is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates changes on both global and regional scales. The following subject areas are covered: (1) water vapor variability; (2) multi-phase water analysis; (3) diabatic heating; (4) MSU (Microwave Sounding Unit) temperature analysis; (5) Optimal precipitation and streamflow analysis; (6) CCM (Community Climate Model) hydrological cycle; (7) CCM1 climate sensitivity to lower boundary forcing; and (8) mesoscale modeling of atmosphere/surface interaction.

  15. Global water cycle

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin; Goodman, Steven J.; Christy, John R.; Fitzjarrald, Daniel E.; Chou, Shi-Hung; Crosson, William; Wang, Shouping; Ramirez, Jorge

    1993-01-01

    This research is the MSFC component of a joint MSFC/Pennsylvania State University Eos Interdisciplinary Investigation on the global water cycle extension across the earth sciences. The primary long-term objective of this investigation is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates change on both global and regional scales. Significant accomplishments in the past year are presented and include the following: (1) water vapor variability; (2) multi-phase water analysis; (3) global modeling; and (4) optimal precipitation and stream flow analysis and hydrologic processes.

  16. Two-Dimensional Electronic Spectroscopy of Chlorophyll a: Solvent Dependent Spectral Evolution.

    PubMed

    Moca, Roberta; Meech, Stephen R; Heisler, Ismael A

    2015-07-09

    The interaction of the monomeric chlorophyll Q-band electronic transition with solvents of differing physical-chemical properties is investigated through two-dimensional electronic spectroscopy (2DES). Chlorophyll constitutes the key chromophore molecule in light harvesting complexes. It is well-known that the surrounding protein in the light harvesting complex fine-tunes chlorophyll electronic transitions to optimize energy transfer. Therefore, an understanding of the influence of the environment on the monomeric chlorophyll electronic transitions is important. The Q-band 2DES is inhomogeneous at early times, particularly in hydrogen bonding polar solvents, but also in nonpolar solvents like cyclohexane. Interestingly this inhomogeneity persists for long times, even up to the nanosecond time scale in some solvents. The reshaping of the 2DES occurs over multiple time scales and was assigned mainly to spectral diffusion. At early times the reshaping is Gaussian-like, hinting at a strong solvent reorganization effect. The temporal evolution of the 2DES response was analyzed in terms of a Brownian oscillator model. The spectral densities underpinning the Brownian oscillator fitting were recovered for the different solvents. The absorption spectra and Stokes shift were also properly described by this model. The extent and nature of inhomogeneous broadening was a strong function of solvent, being larger in H-bonding and viscous media and smaller in nonpolar solvents. The fastest spectral reshaping components were assigned to solvent dynamics, modified by interactions with the solute.

  17. Milestone Report #2: Direct Evaporator Leak and Flammability Analysis Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

    SciTech Connect

    Donna Post Guillen

    2013-09-01

    The direct evaporator is a simplified heat exchange system for an Organic Rankine Cycle (ORC) that generates electricity from a gas turbine exhaust stream. Typically, the heat of the exhaust stream is transferred indirectly to the ORC by means of an intermediate thermal oil loop. In this project, the goal is to design a direct evaporator where the working fluid is evaporated in the exhaust gas heat exchanger. By eliminating one of the heat exchangers and the intermediate oil loop, the overall ORC system cost can be reduced by approximately 15%. However, placing a heat exchanger operating with a flammable hydrocarbon working fluid directly in the hot exhaust gas stream presents potential safety risks. The purpose of the analyses presented in this report is to assess the flammability of the selected working fluid in the hot exhaust gas stream stemming from a potential leak in the evaporator. Ignition delay time for cyclopentane at temperatures and pressure corresponding to direct evaporator operation was obtained for several equivalence ratios. Results of a computational fluid dynamic analysis of a pinhole leak scenario are given.

  18. Toothpaste-like Electrode: A Novel Approach to Optimize the Interface for Solid-State Sodium-Ion Batteries with Ultralong Cycle Life.

    PubMed

    Liu, Lilu; Qi, Xingguo; Ma, Qiang; Rong, Xiaohui; Hu, Yong-Sheng; Zhou, Zhibin; Li, Hong; Huang, Xuejie; Chen, Liquan

    2016-12-07

    A non-sintered method with toothpaste electrode for improving electrode ionic conductivity and reducing interface impedance is introduced in solid-state rechargeable batteries. At 70 °C, this novel solid-state battery can deliver a capacity of 80 mAh g(-1) in a voltage range of 2.5-3.8 V at 0.1C rate using layered oxide Na0.66Ni0.33Mn0.67O2, Na-β″-Al2O3 and sodium metal as cathode, electrolyte and anode, respectively. Moreover, the battery shows a superior stability and high reversibility, with a capacity retention of 90% after 10 000 cycles at 6C rate and a capacity of 79 mAh g(-1) is recovered when the current rate is returned to 0.1C. Furthermore, a very thick electrode with active material mass loading of 6 mg cm(-2) also presents a reasonable electrochemical performance. These results demonstrate that this is a promising approach to solve the interface problem and would open a new route in designing the next generation solid-state battery.

  19. An effective vacuum assisted extraction method for the optimization of labdane diterpenoids from Andrographis paniculata by response surface methodology.

    PubMed

    Wang, Ya-Qi; Wu, Zhen-Feng; Ke, Gang; Yang, Ming

    2014-12-31

    An effective vacuum assisted extraction (VAE) technique was proposed for the first time and applied to extract bioactive components from Andrographis paniculata. The process was carefully optimized by response surface methodology (RSM). Under the optimized experimental conditions, the best results were obtained using a boiling temperature of 65 °C, 50% ethanol concentration, 16 min of extraction time, one extraction cycles and a 12:1 liquid-solid ratio. Compared with conventional ultrasonic assisted extraction and heat reflux extraction, the VAE technique gave shorter extraction times and remarkable higher extraction efficiency, which indicated that a certain degree of vacuum gave the solvent a better penetration of the solvent into the pores and between the matrix particles, and enhanced the process of mass transfer. The present results demonstrated that VAE is an efficient, simple and fast method for extracting bioactive components from A. paniculata, which shows great potential for becoming an alternative technique for industrial scale-up applications.

  20. Optimization of pressurized liquid extraction of Piper gaudichaudianum Kunth leaves.

    PubMed

    Péres, Valéria Flores; Saffi, Jenifer; Melecchi, Maria Inês S; Abad, Fernanda C; Martinez, Migdalia M; Oliveira, Eniz Conceição; Jacques, Rosângela Assis; Caramão, Elina B

    2006-02-10

    Piperaceae family is original from tropical regions and it shows more than 700 species around the world. Piper gaudichaudianum Kunth is the specie more abundant in Brazil, occurring from Northeast to South Brazil. In this paper, it was investigated the influence of some experimental parameters on the pressurized liquid extraction (PLE) of P. gaudichaudianum Kunth leaves, using petroleum ether as extractor solvent. The optimization of the main variables involved in the PLE process (extraction temperature and time) has been done by response surface methodology (RSM) using, as responses, the extraction yield and the chromatographic profile (GC/MS) of the extracts. The optimized procedure employed 3 g of ground leaves, 10 min of extraction and one cycle of extraction at 85 degrees C. The major compounds present in the petroleum ether extracts were: palmitic acid, stearic acid and nerolidol. The results presented in this work show the possibility of using a fast and easy process to recover compounds from P. gaudichaudianum Kunth.

  1. Comparison of ultrasound-enhanced air-assisted liquid-liquid microextraction and low-density solvent-based dispersive liquid-liquid microextraction methods for determination of nonsteroidal anti-inflammatory drugs in human urine samples.

    PubMed

    Barfi, Behruz; Asghari, Alireza; Rajabi, Maryam; Goochani Moghadam, Ahmad; Mirkhani, Nasim; Ahmadi, Farhad

    2015-01-01

    Two dispersive-based liquid-liquid microextraction methods including ultrasound-enhanced air-assisted liquid-liquid microextraction (USE-AALLME) and low-density solvent-based dispersive liquid-liquid microextraction (LDS-DLLME) were compared for the extraction of salicylic acid (the hydrolysis product of acetylsalicylic acid), diclofenac and ibuprofen, as instances of the most commonly used nonsteroidal anti-inflammatory drugs (NSAIDs), in human urine prior to their determination by gas chromatography with flame ionization detection (GC-FID). The influence of different parameters affecting the USE-AALLME (including type and volume of the extraction solvent, sample pH, ionic strength, and simultaneous sonication and number of extraction cycles) and the LDS-DLLME (including type and volume of the extraction and disperser solvents, sample pH, and ionic strength) were investigated to optimize their extraction efficiencies. Both methods are fast, simple and convenient with organic solvent consumption at μL level. However, the best results were obtained using the USE-AALLME method, applying 30 μL of 1-octanol as extraction solvent, 5.0 mL of sample at pH 3.0, without salt addition, and 5 extraction cycles during 20s of sonication. This method was validated based on linearities (r(2) >0 .971), limits of detection (0.1-1.0 μg L(-1)), linear dynamic ranges (0.4-1000.0 μg L(-1)), enrichment factors (115 ± 3-135 ± 3), consumptive indices (0.043-0.037), inter- and intra-day precisions (4.3-4.8 and 5.6-6.1, respectively), and relative recoveries (94-103%). The USE-AALLME in combination with GC-FID, and with no need to derivatization step, was demonstrated to be a simple, inexpensive, sensitive and efficient method to determine NSAIDs in human urine samples.

  2. Cleanup of Savannah River Plant solvent using solid sorbents

    SciTech Connect

    Mailen, J.C.; Tallent, O.K.

    1985-04-01

    The degradation products produced in Purex solvent by exposure to nitric acid and radiation can be divided into two groups: those which are removed by scrubbing with sodium carbonate solutions and those which are not; these latter materials are called secondary degradation products. This study investigated the use of solid sorbents for removal of the secondary degradation products from first-cycle Savannah River Plant solvent that had been previously washed with sodium carbonate solution. Silica gel, activated charcoal, macroreticular resin, attapulgite clay and activated alumina were the sorbents investigated in preliminary testing. Activated alumina was found to be most effective for improving phase separation of the solvent from sodium carbonate solutions and for increasing the interfacial tension. The activated alumina was also the sorbent most useful for removing complexants which retain plutonium at low acidity, but it was less effective in removing anionic surfactants and ruthenium. We found that the capacity of the activated alumina was greatly improved by drying the solvent before treatment.

  3. Cycle Analysis

    SciTech Connect

    Wright, Steven A.

    2012-03-20

    1. The Cycle Analysis code is an Microsoft Excel code that performs many different types of thermodynamic cycle analysis for power producing systems. The code will calculate the temperature and pressure and all other thermodynamic properties at the inlet and outlet of each component. The code also calculates the power that is produced, the efficiency, and the heat transported in the heater, gas chiller and recuperators. The code provides a schematic of the loop and provides the temperature and pressure at each location in the loop. The code also provides a T-S (temperature-entropy) diagram of the loop and often it provides an pressure enthalpy plot as well. 2. This version of the code concentrates on supercritical CO2 power cycles, but by simply changing the name of the working fluid many other types of fluids can be analyzed. The Cycle Analysis code provided here contains 18 different types of power cycles. Each cycle is contained in one worksheet or tab that the user can select. The user can change the yellow highlighted regions to perform different thermodynamic cycle analysis.

  4. Simultaneous extraction of flavonoids from Chamaecyparis obtusa using deep eutectic solvents as additives of conventional extractions solvents.

    PubMed

    Tang, Baokun; Park, Ha Eun; Row, Kyung Ho

    2015-01-01

    Three flavones (quercetin, myricetin and amentoflavone) were extracted from Chamaecyparis obtusa leaves using deep eutectic solvents (DESs) as additives to conventional extractions solvents. Sixteen DESs were synthesized from different salts and hydrogen bond donors. In addition, C. obtusa was extracted under optimal conditions of methanol as the solvent in the heating process (60°C) for 120 min at a solid/liquid ratio of 80%. Under these optimal conditions, a good linear relationship was observed at analyte concentrations ranging from 5.0 to 200.0 μg/mL (R(2) > 0.999). The extraction recovery ranged from 96.7 to 103.3% with the inter- and intraday relative standard deviations of <4.97%. Under the optimal conditions, from C. obtusa, the quantities of quercetin, myricetin and amentoflavone extracted were 325.90, 8.66 and 50.34 µg/mL, respectively. Overall, DESs are expected to have a wide range of applications.

  5. Versatile Production of Poly(Epsilon-Caprolactone) Fibers by Electrospinning Using Benign Solvents

    PubMed Central

    Liverani, Liliana; Boccaccini, Aldo R.

    2016-01-01

    The electrospinning technique is widely used for the fabrication of micro- and nanofibrous structures. Recent studies have focused on the use of less toxic and harmful solvents (benign solvents) for electrospinning, even if those solvents usually require an accurate and longer process of optimization. The aim of the present work is to demonstrate the versatility of the use of benign solvents, like acetic acid and formic acid, for the fabrication of microfibrous and nanofibrous electrospun poly(epsilon-caprolactone) mats. The solvent systems were also shown to be suitable for the fabrication of electrospun structures with macroporosity, as well as for the fabrication of composite electrospun mats, fabricated by the addition of bioactive glass (45S5 composition) particles in the polymeric solution. PMID:28335202

  6. Versatile Production of Poly(Epsilon-Caprolactone) Fibers by Electrospinning Using Benign Solvents.

    PubMed

    Liverani, Liliana; Boccaccini, Aldo R

    2016-04-15

    The electrospinning technique is widely used for the fabrication of micro- and nanofibrous structures. Recent studies have focused on the use of less toxic and harmful solvents (benign solvents) for electrospinning, even if those solvents usually require an accurate and longer process of optimization. The aim of the present work is to demonstrate the versatility of the use of benign solvents, like acetic acid and formic acid, for the fabrication of microfibrous and nanofibrous electrospun poly(epsilon-caprolactone) mats. The solvent systems were also shown to be suitable for the fabrication of electrospun structures with macroporosity, as well as for the fabrication of composite electrospun mats, fabricated by the addition of bioactive glass (45S5 composition) particles in the polymeric solution.

  7. Firing of pulverized solvent refined coal

    DOEpatents

    Derbidge, T. Craig; Mulholland, James A.; Foster, Edward P.

    1986-01-01

    An air-purged burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired without the coking thereof on the burner components. The air-purged burner is designed for the firing of pulverized solvent refined coal in a tangentially fired boiler.

  8. Solvent Extraction of Furfural From Biomass

    NASA Technical Reports Server (NTRS)

    Humphrey, M. F.

    1984-01-01

    Solvent-extraction method reduces energy required to remove furfural produced during acid hydrolysis of biomass. Acid hydrolysis performed in vessel containing both solvents and reacting ingredients. With intimate contact between solvents and aqueous hydrolyis liqour, furfural removed form liquor almost as fast as it forms.

  9. The solvent component of macromolecular crystals

    SciTech Connect

    Weichenberger, Christian X.; Kantardjieff, Katherine; Rupp, Bernhard

    2015-04-30

    On average, the mother liquor or solvent and its constituents occupy about 50% of a macromolecular crystal. Ordered as well as disordered solvent components need to be accurately accounted for in modelling and refinement, often with considerable complexity. The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.

  10. Simultaneous chemical fingerprint and quantitative analysis of Rhizoma Smilacis Glabrae by accelerated solvent extraction and high-performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Dai, Weiquan; Zhao, Weiquan; Gao, Fangyuan; Shen, Jingjing; Lv, Diya; Qi, Yunpeng; Fan, Guorong

    2015-05-01

    Rhizoma Smilacis Glabrae (RSG) is a well-known herbal medicine with the homology of medicine and food. In this study, simultaneous chemical fingerprint and quantitative analysis of the bioactive flavonoid components of RSG were developed using accelerated solvent extraction and high-performance liquid chromatography coupled with ion trap tandem mass spectrometry. The operational parameters of accelerated solvent extraction including extraction solvent, extraction temperature, static extraction time, solid-to-liquid ratio, and extraction cycles were optimized. Hierarchical cluster analysis, similarity analysis, and principal component analysis were performed to evaluate the similarity and variation of the samples collected from several provinces in China. Subsequently, high-performance liquid chromatography fingerprints were established for the discrimination of 16 batches of RSG samples, and the major six flavonoids, namely, toxifolin, neoastilbin, astilbin, neoisoastilbin, isoastilbin, and engeletin were then quantitatively determined. The calibration curves for all the six analytes showed good linearity (r(2) > 0.999), and the limits of detection and quantification were less than 0.10 and 0.27 μg·mL(-1) , respectively. Therefore, the proposed extraction and determination methods were proved to be robust and reliable for the quality control of RSG.

  11. Solvent cleaning system and method for removing contaminants from solvent used in resin recycling

    DOEpatents

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2009-01-06

    A two step solvent and carbon dioxide based system that produces essentially contaminant-free synthetic resin material and which further includes a solvent cleaning system for periodically removing the contaminants from the solvent so that the solvent can be reused and the contaminants can be collected and safely discarded in an environmentally safe manner.

  12. Cycling injuries.

    PubMed Central

    Cohen, G. C.

    1993-01-01

    Bicycle-related injuries have increased as cycling has become more popular. Most injuries to recreational riders are associated with overuse or improper fit of the bicycle. Injuries to racers often result from high speeds, which predispose riders to muscle strains, collisions, and falls. Cyclists contact bicycles at the pedals, seat, and handlebars. Each is associated with particular cycling injuries. Images Figure 1 Figure 3 Figure 4 Figure 5 PMID:8471908

  13. Solute-solvent and solvent-solvent interactions in the preferential solvation of 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide in 24 binary solvent mixtures.

    PubMed

    Bevilaqua, Tharly; Gonçalves, Thaini F; Venturini, Cristina de G; Machado, Vanderlei G

    2006-11-01

    The molar transition energy (E(T)) polarity values for the dye 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide were collected in binary mixtures comprising a hydrogen-bond accepting (HBA) solvent (acetone, acetonitrile, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF)) and a hydrogen-bond donating (HBD) solvent (water, methanol, ethanol, propan-2-ol, and butan-1-ol). Data referring to mixtures of water with alcohols were also analyzed. These data were used in the study of the preferential solvation of the probe, in terms of both solute-solvent and solvent-solvent interactions. These latter interactions are of importance in explaining the synergistic behavior observed for many mixed solvent systems. All data were successfully fitted to a model based on solvent-exchange equilibria. The E(T) values of the dye dissolved in the solvents show that the position of the solvatochromic absorption band of the dye is dependent on the medium polarity. The solvation of the dye in HBA solvents occurs with a very important contribution from ion-dipole interactions. In HBD solvents, the hydrogen bonding between the dimethylamino group in the dye and the OH group in the solvent plays an important role in the solvation of the dye. The interaction of the hydroxylic solvent with the other component in the mixture can lead to the formation of hydrogen-bonded complexes, which solvate the dye using a lower polar moiety, i.e. alkyl groups in the solvents. The dye has a hydrophobic nature and a dimethylamino group with a minor capability for hydrogen bonding with the medium in comparison with the phenolate group present in Reichardt's pyridiniophenolate. Thus, the probe is able to detect solvent-solvent interactions, which are implicit to the observed synergistic behavior.

  14. Batch extracting process using magneticparticle held solvents

    DOEpatents

    Nunez, Luis; Vandergrift, George F.

    1995-01-01

    A process for selectively removing metal values which may include catalytic values from a mixture containing same, wherein a magnetic particle is contacted with a liquid solvent which selectively dissolves the metal values to absorb the liquid solvent onto the magnetic particle. Thereafter the solvent-containing magnetic particles are contacted with a mixture containing the heavy metal values to transfer metal values into the solvent carried by the magnetic particles, and then magnetically separating the magnetic particles. Ion exchange resins may be used for selective solvents.

  15. Enhanced production and organic solvent stability of a protease fromBrevibacillus laterosporus strain PAP04

    PubMed Central

    Anbu, P.

    2016-01-01

    A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media. PMID:27007657

  16. Enhanced production and organic solvent stability of a protease from Brevibacillus laterosporus strain PAP04.

    PubMed

    Anbu, P

    2016-01-01

    A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media.

  17. Evaluation of Co-solvents with supercritical fluid extraction of atrazine from soil.

    PubMed

    Senseman, S A; Ketchersid, M L

    2000-04-01

    Supercritical fluid extraction (SFE) with CO(2) has been successfully applied to herbicide extractions from soil. The objectives of this work were to compare extraction efficiency of atrazine from soil using different types and quantities of co-solvent modifiers under a specified set of SFE instrument conditions and to determine the ruggedness of an optimized extraction program and co-solvent on several soils with varying characteristics. The effect of 18 co-solvents on atrazine extraction from Lufkin fine sandy loam was determined using a completely randomized design with six replications. Extractions of Lufkin soil using the more nonpolar co-solvents had recovery similar to extractions where no co-solvent was added. The co-solvents that showed high extraction efficiency, low incidences of restrictor plugging, and ease of cleaning extraction cells were acetone, acetone:water mixtures (with and without 1% triethylamine), and acetonitrile. The addition of 1% triethylamine (TEA) did not increase recovery significantly. The 9:1 acetone:water mixture with 1% TEA was used for the soil comparison because of the high atrazine recovery and low water content. No differences in atrazine recovery were detected between extractions of the four representative soils when the same extraction conditions were employed. No cleanup steps were included in the procedure, yet adequate chromatography results were obtained suggesting some selectivity for this procedure. These data indicate that SFE with optimized conditions and appropriate co-solvents is a relatively robust method that can effectively be used in soil extractions of atrazine.

  18. Effect of solvents on the enzyme mediated degradation of copolymers

    NASA Astrophysics Data System (ADS)

    Banerjee, Aditi; Chatterjee, Kaushik; Madras, Giridhar

    2015-09-01

    The biodegradation of polycaprolactone (PCL), polylactic acid (PLA), polyglycolide (PGA) and their copolymers, poly (lactide-co-glycolide) and poly (D, L-lactide-co-caprolactone) (PLCL) was investigated. The influence of different solvents on the degradation of these polymers at 37 °C in the presence of two different lipases namely Novozym 435 and the free lipase of porcine pancreas was investigated. The rate coefficients for the polymer degradation and enzyme deactivation were determined using continuous distribution kinetics. Among the homopolymers, the degradation of PGA was nearly an order of magnitude lower than that for PCL and PLA. The overall rate coefficients of the copolymers were higher than their respective homopolymers. Thus, PLCL degraded faster than either PCL or PLA. The degradation was highly dependent on the viscosity of the solvent used with the highest degradation observed in acetone. The degradation of the polymers in acetone was nearly twice that observed in dimethyl sulfoxide indicating that the degradation decreases with increase in the solvent viscosity. The degradation of the polymers in water-solvent mixtures indicated an optimal water content of 2.5 wt% of water.

  19. Effect of operating parameters on mechanical expression of solvent-soaked soybean-grits.

    PubMed

    Sinha, Lalan Kumar; Haldar, Swarrna; Majumdar, Gautam Chandra

    2015-05-01

    Oil from soybean is obtained mostly by solvent extraction of soybean flakes. Legislation banning the use of hexane as solvent for extracting edible vegetable oil has forced a search for an alternative solvent and for developing a suitable oil recovery process. Expellers are being used for obtaining vegetable oil by mechanical means (expression) from oil seeds having oil content higher than 20 %. It was felt, in view of the stiffness of the soybean matrix, a combination of solvent treatment and expression could be a cheaper alternative; thus an attempt has been made here to develop a two stage process constituting soaking of soybean grits in solvent followed by mechanical compression (hydraulic press) of solvent-soaked grits to recover oil. The present work aimed at studying the effect of various process parameters on oil yield from solvent soaked soybean-grits during soaking as well as pressing stages using the solvents: hexane, ethanol (alternative solvent). The process parameters were identified through holistic approach. The dependant variable was oil recovery (expressed as fraction of initial oil content of soybean) whereas the independent parameters were particle size, solvent-bean mass ratio, soaking time, soaking temperature, applied pressure and pressing time. The effect of each of the above parameters on fractional oil recovery (FOR) was studied. The results of the present study indicate that the above parameters have a significant effect on the fractional oil recovery with particle size, soaking temperature, soaking time and pressing time being the most significant factors. The present study also indicates that ethanol can be used as an alternate solvent to hexane by optimizing the factors as discussed in this paper.

  20. Solvent Annealing in Selective Solvents: A Novel Method to Tune the Morphology of Low Band Gap Polymer:Bis-Fullerene Heterojunctions

    NASA Astrophysics Data System (ADS)

    Dadmun, Mark; Chen, Huipeng; Hsiao, Yu-Che; Hu, Bin

    2014-03-01

    One of the most important challenges facing our society is the development of technologies for renewable energy conversion. Polymeric bulk-heterojunction (BHJ) photovoltaics, based on conjugated polymers and fullerenes, are an economically viable option for low cost renewable power generation. The most promising conjugated polymer:fullerene active layers in organic photovoltaics now utilize low band-gap (LBG) copolymers. Unfortunately, for most of these LBG devices, the as-cast film is not usually optimal, and there are few further treatment available after film deposition to optimize the morphology. To address this problem, we have exploited the selective solubility of the LBG:fullerene nanocomposite components to direct the assembly of these mixtures by annealing in the vapor of a selective solvent. Our recent work demonstrates that annealing in a solvent that is selective to the fullerene forms a sample with fullerene aggregation, while annealing in a solvent vapor that is selective to the polymer forms a thin film with polymer precipitation. There is also a direct correlation between the resultant morphology and OPV performance, increasing PCE by 190%. These results indicate that solvent annealing and solvent choice provides a unique tool to precisely tune the morphology of CP:Fullerene BHJ systems, optimizing the morphology and performance of the active layer.

  1. Steady state recycling chromatography with an integrated solvent removal unit - separation of glucose and galactose.

    PubMed

    Hellstén, Sanna; Siitonen, Jani; Mänttäri, Mika; Sainio, Tuomo

    2012-08-17

    A process concept where a solvent removal unit is integrated to a steady-state recycling chromatography process (SSR-SR) offers a possibility to significantly increase the performance of single column chromatographic separation. The advantages of solvent removal for a difficult separation task at conditions typical for industrial scale chromatography were demonstrated by investigating the performance of SSR-SR in separation of glucose and galactose. Two limits for the extent of solvent removal were imposed: maximum total concentration of the solution fed into the column (viscosity limit) and the maximum total concentration achievable in the solvent removal unit (solubility or osmotic pressure limit). The process was optimized using numerical simulation. Three SSR-SR configurations with different positions of the solvent removal unit were compared with (1) the conventional batch process, (2) SSR without solvent removal, and (3) batch process with solvent removal. SSR-SR was found to always improve the productivity. In addition, solvent removal reduced eluent consumption in most cases. The concentration limits and the concentration of the fresh feed were shown to determine which SSR-SR configuration yields the best performance.

  2. Accelerated, microwave-assisted, and conventional solvent extraction methods affect anthocyanin composition from colored grains.

    PubMed

    Abdel-Aal, El-Sayed M; Akhtar, Humayoun; Rabalski, Iwona; Bryan, Michael

    2014-02-01

    Anthocyanins are important dietary components with diverse positive functions in human health. This study investigates effects of accelerated solvent extraction (ASE) and microwave-assisted extraction (MAE) on anthocyanin composition and extraction efficiency from blue wheat, purple corn, and black rice in comparison with the commonly used solvent extraction (CSE). Factorial experimental design was employed to study effects of ASE and MAE variables, and anthocyanin extracts were analyzed by spectrophotometry, high-performance liquid chromatography-diode array detector (DAD), and liquid chromatography-mass spectrometry chromatography. The extraction efficiency of ASE and MAE was comparable with CSE at the optimal conditions. The greatest extraction by ASE was achieved at 50 °C, 2500 psi, 10 min using 5 cycles, and 100% flush. For MAE, a combination of 70 °C, 300 W, and 10 min in MAE was the most effective in extracting anthocyanins from blue wheat and purple corn compared with 50 °C, 1200 W, and 20 min for black rice. The anthocyanin composition of grain extracts was influenced by the extraction method. The ASE extraction method seems to be more appropriate in extracting anthocyanins from the colored grains as being comparable with the CSE method based on changes in anthocyanin composition. The method caused lower structural changes in anthocaynins compared with the MAE method. Changes in blue wheat anthocyanins were lower in comparison with purple corn or black rice perhaps due to the absence of acylated anthocyanin compounds in blue wheat. The results show significant differences in anthocyanins among the 3 extraction methods, which indicate a need to standardize a method for valid comparisons among studies and for quality assurance purposes.

  3. Vapor Compression Cycle Design Program (CYCLE_D)

    National Institute of Standards and Technology Data Gateway

    SRD 49 NIST Vapor Compression Cycle Design Program (CYCLE_D) (PC database for purchase)   The CYCLE_D database package simulates the vapor compression refrigeration cycles. It is fully compatible with REFPROP 9.0 and covers the 62 single-compound refrigerants . Fluids can be used in mixtures comprising up to five components.

  4. LIFE CYCLE ASSESSMENT FOR PC BLEND 2 AIRCRAFT RADOME DEPAINTER

    EPA Science Inventory

    This report describes the life cycle assessment on a potential replacement solvent blend for aircraft radome depainting at the Oklahoma City Air Logistics Center at Tinker Air Force Base. The life cycle assessment is composed of three separate but interrelated components: life cy...

  5. Solvent cavitation under solvophobic confinement

    NASA Astrophysics Data System (ADS)

    Ashbaugh, Henry S.

    2013-08-01

    The stability of liquids under solvophobic confinement can tip in favor of the vapor phase, nucleating a liquid-to-vapor phase transition that induces attractive forces between confining surfaces. In the case of water adjacent to hydrophobic surfaces, experimental and theoretical evidence support confinement-mediated evaporation stabilization of biomolecular and colloidal assemblies. The macroscopic thermodynamic theory of cavitation under confinement establishes the connection between the size of the confining surfaces, interfacial free energies, and bulk solvent pressure with the critical evaporation separation and interfacial forces. While molecular simulations have confirmed the broad theoretical trends, a quantitative comparison based on independent measurements of the interfacial free energies and liquid-vapor coexistence properties has, to the best of our knowledge, not yet been performed. To overcome the challenges of simulating a large number of systems to validate scaling predictions for a three-dimensional fluid, we simulate both the forces and liquid-vapor coexistence properties of a two-dimensional Lennard-Jones fluid confined between solvophobic plates over a range of plate sizes and reservoir pressures. Our simulations quantitatively agree with theoretical predictions for solvent-mediated forces and critical evaporation separations once the length dependence of the solvation free energy of an individual confining plate is taken into account. The effective solid-liquid line tension length dependence results from molecular scale correlations for solvating microscopic plates and asymptotically decays to the macroscopic value for plates longer than 150 solvent diameters. The success of the macroscopic thermodynamic theory at describing two-dimensional liquids suggests application to surfactant monolayers to experimentally confirm confinement-mediated cavitation.

  6. Advanced integrated solvent extraction systems

    SciTech Connect

    Horwitz, E.P.; Dietz, M.L.; Leonard, R.A.

    1997-10-01

    Advanced integrated solvent extraction systems are a series of novel solvent extraction (SX) processes that will remove and recover all of the major radioisotopes from acidic-dissolved sludge or other acidic high-level wastes. The major focus of this effort during the last 2 years has been the development of a combined cesium-strontium extraction/recovery process, the Combined CSEX-SREX Process. The Combined CSEX-SREX Process relies on a mixture of a strontium-selective macrocyclic polyether and a novel cesium-selective extractant based on dibenzo 18-crown-6. The process offers several potential advantages over possible alternatives in a chemical processing scheme for high-level waste treatment. First, if the process is applied as the first step in chemical pretreatment, the radiation level for all subsequent processing steps (e.g., transuranic extraction/recovery, or TRUEX) will be significantly reduced. Thus, less costly shielding would be required. The second advantage of the Combined CSEX-SREX Process is that the recovered Cs-Sr fraction is non-transuranic, and therefore will decay to low-level waste after only a few hundred years. Finally, combining individual processes into a single process will reduce the amount of equipment required to pretreat the waste and therefore reduce the size and cost of the waste processing facility. In an ongoing collaboration with Lockheed Martin Idaho Technology Company (LMITCO), the authors have successfully tested various segments of the Advanced Integrated Solvent Extraction Systems. Eichrom Industries, Inc. (Darien, IL) synthesizes and markets the Sr extractant and can supply the Cs extractant on a limited basis. Plans are under way to perform a test of the Combined CSEX-SREX Process with real waste at LMITCO in the near future.

  7. Helium process cycle

    DOEpatents

    Ganni, Venkatarao

    2008-08-12

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  8. Helium process cycle

    DOEpatents

    Ganni, Venkatarao

    2007-10-09

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  9. SOLVENT EXTRACTION PROCESS FOR PLUTONIUM

    DOEpatents

    Seaborg, G.T.

    1959-04-14

    The separation of plutonium from aqueous inorganic acid solutions by the use of a water immiscible organic extractant liquid is described. The plutonium must be in the oxidized state, and the solvents covered by the patent include nitromethane, nitroethane, nitropropane, and nitrobenzene. The use of a salting out agents such as ammonium nitrate in the case of an aqueous nitric acid solution is advantageous. After contacting the aqueous solution with the organic extractant, the resulting extract and raffinate phases are separated. The plutonium may be recovered by any suitable method.

  10. Comparisons of amine solvents for post-combustion CO{sub 2} capture: A multi-objective analysis approach

    SciTech Connect

    Lee, Anita S; Eslick, John C; Miller, David C; Kitchin, John R

    2013-10-01

    Amine solvents are of great interest for post-combustion CO{sub 2} capture applications. Although the development of new solvents is predominantly conducted at the laboratory scale, the ability to assess the performance of newly developed solvents at the process scale is crucial to identifying the best solvents for CO{sub 2} capture. In this work we present a methodology to evaluate and objectively compare the process performance of different solvents. We use Aspen Plus, with the electrolyte-NRTL thermodynamic model for the solvent CO{sub 2} interactions, coupled with a multi-objective genetic algorithm optimization to determine the best process design and operating conditions for each solvent. This ensures that the processes utilized for the comparison are those which are best suited for the specific solvent. We evaluate and compare the process performance of monoethanolamine (MEA), diethanolamine (DEA), and 2-amino-2-methyl-1-propanol (AMP) in a 90% CO{sub 2} capture process from a 550 MW coal fired power plant. From our analysis the best process specifications are amine specific and with those specific, optimized specifications DEA has the potential to be a better performing solvent than MEA, with a lower energy penalty and lower capital cost investment.

  11. Li-Ion Cells Employing Electrolytes With Methyl Propionate and Ethyl Butyrate Co-Solvents

    NASA Technical Reports Server (NTRS)

    Smart, Marshall C.; Bugga, Ratnakumar V.

    2011-01-01

    Future NASA missions aimed at exploring Mars and the outer planets require rechargeable batteries that can operate at low temperatures to satisfy the requirements of such applications as landers, rovers, and penetrators. A number of terrestrial applications, such as hybrid electric vehicles (HEVs) and electric vehicles (EVs) also require energy storage devices that can operate over a wide temperature range (i.e., -40 to +70 C), while still providing high power capability and long life. Currently, the state-of-the-art lithium-ion system has been demonstrated to operate over a wide range of temperatures (-30 to +40 C); however, the rate capability at the lower temperatures is very poor. These limitations at very low temperatures are due to poor electrolyte conductivity, poor lithium intercalation kinetics over the electrode surface layers, and poor ionic diffusion in the electrode bulk. Two wide-operating-temperature-range electrolytes have been developed based on advances involving lithium hexafluorophosphate-based solutions in carbonate and carbonate + ester solvent blends, which have been further optimized in the context of the technology and targeted applications. The approaches employed include further optimization of electrolytes containing methyl propionate (MP) and ethyl butyrate (EB), which are effective co-solvents, to widen the operating temperature range beyond the baseline systems. Attention was focused on further optimizing ester-based electrolyte formulations that have exhibited the best performance at temperatures ranging from -60 to +60 C, with an emphasis upon improving the rate capability at -20 to -40 C. This was accomplished by increasing electrolyte salt concentration to 1.20M and increasing the ester content to 60 percent by volume to increase the ionic conductivity at low temperatures. Two JPL-developed electrolytes 1.20M LiPF6 in EC+EMC+MP (20:20:60 v/v %) and 1.20M LiPF6 in EC+EMC+EB (20:20:60 v/v %) operate effectively over a wide

  12. The solvent component of macromolecular crystals

    PubMed Central

    Weichenberger, Christian X.; Afonine, Pavel V.; Kantardjieff, Katherine; Rupp, Bernhard

    2015-01-01

    The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands. PMID:25945568

  13. Dynamics around solutes and solute-solvent complexes in mixed solvents.

    PubMed

    Kwak, Kyungwon; Park, Sungnam; Fayer, M D

    2007-09-04

    Ultrafast 2D-IR vibrational echo experiments, IR pump-probe experiments, and FT-IR spectroscopy of the hydroxyl stretch of phenol-OD in three solvents, CCl4, mesitylene (1, 3, 5 trimethylbenzene), and the mixed solvent of mesitylene and CCl4 (0.83 mole fraction CCl4), are used to study solute-solvent dynamics via observation of spectral diffusion. Phenol forms a complex with Mesitylene. In the mesitylene solution, there is only complexed phenol; in the CCl4 solution, there is only uncomplexed phenol; and in the mixed solvent, both phenol species are present. Dynamics of the free phenol in CCl4 or the mixed solvent are very similar, and dynamics of the complex in mesitylene and in the mixed solvent are very similar. However, there are differences in the slowest time scale dynamics between the pure solvents and the mixed solvents. The mixed solvent produces slower dynamics that are attributed to first solvent shell solvent composition variations. The composition variations require a longer time to randomize than is required in the pure solvents, where only density variations occur. The experimental results and recent MD simulations indicate that the solvent structure around the solute may be different from the mixed solvent's mole fraction.

  14. [Low-density solvent-based solvent demulsification dispersive liquid-liquid microextraction combined with gas chromatography for determination of polycyclic aromatic hydrocarbons in water samples].

    PubMed

    Zhu, Benqiong; Chen, Hao; Li, Shengqing

    2012-02-01

    A novel method of low-density solvent-based solvent demulsification dispersive liquid-liquid microextraction (SD-DLLME) was developed for the determination of eight polycyclic aromatic hydrocarbons (PAHs) in water samples by gas chromatography-flame ionization detection (GC-FID). Conventional DLLME methods usually employ organic solvents heavier than water as the extraction solvents and achieve the phase separation through centrifugation. On the contrary, in this proposed extraction procedure, a mixture of low-density extraction solvent (toluene) and dispersive solvent (acetone) was injected into the aqueous sample solution to form an emulsion. A demulsification solvent (acetonitrile) was then injected into the aqueous solution to break up the emulsion, which turned clear quickly and was separated into two layers. The upper layer (toluene) was collected and analyzed by GC. No centrifugation was required in this procedure. Factors affecting the extraction efficiency such as the type and volume of dispersive solvent, extraction solvent and de-emulsifier were investigated in detail. Under the optimized conditions, the proposed method provided a good linearity in the range of 20 - 500 microg/L (r2 = 0.994 2 - 0.999 9). The limits of detection (S/N = 3) were in the range of 0.52 - 5.11 microg/L. The relative standard deviations (RSDs) for the determination of 40 microg/L PAHs were in the range of 2.2% - 13.6% (n = 5). The proposed method is fast, efficient and convenient. It has been successfully applied to the determination of PAHs in natural water samples with the spiked recoveries of 80.2% - 115.1%.

  15. Asphaltene aggregation in organic solvents.

    PubMed

    Oh, Kyeongseok; Ring, Terry A; Deo, Milind D

    2004-03-01

    Asphaltenic solids formed in the Rangely field in the course of a carbon dioxide flood and heptane insolubles in the oil from the same field were used in this study. Four different solvents were used to dissolve the asphaltenes. Near-infrared (NIR) spectroscopy was used to determine the onset of asphaltene precipitation by heptane titration. When the onset values were plotted versus asphaltene concentrations, distinct break points (called critical aggregation concentrations (CAC) in this paper) were observed. CACs for the field asphaltenes dissolved in toluene, trichloroethylene, tetrahydrofuran, and pyridine occurred at concentrations of 3.0, 3.7, 5.0, and 8.2 g/l, respectively. CACs are observed at similar concentrations as critical micelle concentrations (CMC) for the asphaltenes in the solvents employed and can be interpreted to be the points at which rates of asphaltene aggregations change. CMC values of asphaltenes determined from surface tension measurements (in pyridine and TCE) were slightly higher than the CAC values measured by NIR onset measurements. The CAC for heptane-insoluble asphaltenes in toluene was 3.1 g/l. Thermal gravimetric analysis (TGA) and elemental compositions of the two asphaltenes showed that the H/C ratio of the heptane-insoluble asphaltenes was higher and molecular weight (measured by vapor pressure osmometry) was lower.

  16. Development of Solvent Extraction Approach to Recycle Enriched Molybdenum Material

    SciTech Connect

    Tkac, Peter; Brown, M. Alex; Sen, Sujat; Bowers, Delbert L.; Wardle, Kent; Copple, Jacqueline M.; Pupek, Krzysztof Z.; Dzwiniel, Trevor L.; Pereira, Candido; Krumdick, Gregory K.; Vandegrift, George F.

    2016-06-01

    Argonne National Laboratory, in cooperation with Oak Ridge National Laboratory and NorthStar Medical Technologies, LLC, is developing a recycling process for a solution containing valuable Mo-100 or Mo-98 enriched material. Previously, Argonne had developed a recycle process using a precipitation technique. However, this process is labor intensive and can lead to production of large volumes of highly corrosive waste. This report discusses an alternative process to recover enriched Mo in the form of ammonium heptamolybdate by using solvent extraction. Small-scale experiments determined the optimal conditions for effective extraction of high Mo concentrations. Methods were developed for removal of ammonium chloride from the molybdenum product of the solvent extraction process. In large-scale experiments, very good purification from potassium and other elements was observed with very high recovery yields (~98%).

  17. Solvent effect on the vibrational spectra of Carvedilol

    NASA Astrophysics Data System (ADS)

    Billes, Ferenc; Pataki, Hajnalka; Unsalan, Ozan; Mikosch, Hans; Vajna, Balázs; Marosi, György

    2012-09-01

    Carvedilol (CRV) is an important medicament for heart arrhythmia. The aim of this work was the interpretation of its vibrational spectra with consideration on the solvent effect. Infrared and Raman spectra were recorded in solid state as well in solution. The experimental spectra were evaluated using DFT quantum chemical calculations computing the optimized structure, atomic net charges, vibrational frequencies and force constants. The same calculations were done for the molecule in DMSO and aqueous solutions applying the PCM method. The calculated force constants were scaled to the experimentally observed solid state frequencies. The characters of the vibrational modes were determined by their potential energy distributions. Solvent effects on the molecular properties were interpreted. Based on these results vibrational spectra were simulated.

  18. Solvent effect on the vibrational spectra of Carvedilol.

    PubMed

    Billes, Ferenc; Pataki, Hajnalka; Unsalan, Ozan; Mikosch, Hans; Vajna, Balázs; Marosi, György

    2012-09-01

    Carvedilol (CRV) is an important medicament for heart arrhythmia. The aim of this work was the interpretation of its vibrational spectra with consideration on the solvent effect. Infrared and Raman spectra were recorded in solid state as well in solution. The experimental spectra were evaluated using DFT quantum chemical calculations computing the optimized structure, atomic net charges, vibrational frequencies and force constants. The same calculations were done for the molecule in DMSO and aqueous solutions applying the PCM method. The calculated force constants were scaled to the experimentally observed solid state frequencies. The characters of the vibrational modes were determined by their potential energy distributions. Solvent effects on the molecular properties were interpreted. Based on these results vibrational spectra were simulated.

  19. Organic solvent simulations under non-periodic boundary conditions: A library of effective potentials for the GLOB model

    NASA Astrophysics Data System (ADS)

    Mancini, Giordano; Brancato, Giuseppe; Chandramouli, Balasubramanian; Barone, Vincenzo

    2015-04-01

    We extend the library of solvents that can be treated using the GLOB (general liquid optimized boundary) method, that allows to perform MD simulations under non-periodic boundary conditions (NPBC) optimizing effective potentials between explicit molecules and the boundary for four organic solvents: CHCl3, CCl4, CH3OH and CH3CN. We show that GLOB allows reducing the number of explicit solvent shells to be included, while yielding results comparable with PBC and significant advantages over simulations without explicit boundaries. Finally, we provide polynomial fittings for all available GLOB effective potentials (including SPC water) to simplify their implementation in NPBC MD simulations.

  20. Effect of solvents on the electrochemical properties of binder-free sulfur cathode films in lithium–sulfur batteries

    SciTech Connect

    Ryu, Ho-Suk; Kim, Byeong-Wook; Park, Jin-Woo; Nam, Tae-Hyun; Cho, Kwon-Koo; Kim, Ki-Won; Ahn, Jou-Hyeon; Ahn, Hyo-Jun

    2016-10-15

    Highlights: • The binder-free sulfur electrode with high sulfur contents of 75 wt.% was fabricated. • The binder-free sulfur electrode using NMP solvents showed 784 mAh g{sup −1} after 40 cycles. • The solvent affect the electrochemical properties of binder-free sulfur electrode films. - Abstract: The effects of solvents on the preparation of sulfur cathodes were investigated by fabricating binder-free sulfur electrode films using three different solvents: 1-methyl-2-pyrrolidinone (NMP), acetonitrile, and deionized water. These solvents are commonly employed to dissolve binders used to prepare sulfur cathodes for lithium–sulfur batteries. The sulfur electrode fabricated with NMP had a higher discharge capacity and longer cycle life than the ones fabricated with acetonitrile and deionized water. Better adhesion between the current collector and the sulfur electrode accounted for the improved capacity and cycle life of the battery. In addition, the stability of the electrode in the electrolyte was a result of the solubility of sulfur in the solvent. We thus concluded that the solvents used in the fabrication of sulfur electrodes had a positive influence on the electrochemical properties of Li–S batteries.

  1. Menu Cycles.

    ERIC Educational Resources Information Center

    Clayton, Alfred; Almony, John

    The curriculum guide for commercial foods instruction is designed to aid the teacher in communicating the importance of menu cycles in commercial food production. It also provides information about the necessary steps in getting food from the raw form to the finished product, and then to the consumer. In addition to providing information on how to…

  2. The influence of organic sample solvents on the separation efficiency of basic compounds under strong cation exchange mode.

    PubMed

    Long, Zhen; Yu, Dongping; Liu, Yanfang; Du, Nana; Tao, Yanduo; Mei, Lijuan; Guo, Zhimou; Liang, Xinmiao

    2015-05-04

    This study investigated the influence of organic sample solvents on separation efficiency of basic compounds under strong cation exchange (SCX) mode. The mixtures of acidic aqueous solution and organic solvent such as acetonitrile, ethanol, methanol and dimethyl sulfoxide (DMSO) were tested as sample solvents. For later-eluting analytes, the increase of sample solvent elution strength was responsible for the decrease of separation efficiency. Thus, sample solvents with weak elution strength could provide high separation efficiencies. For earlier-eluting analytes, the retention of organic sample solvents was the main factor affecting separation efficiency. Weakly retained solvents could provide high separation efficiency. In addition, an optimized approach was proposed to reduce the effect of organic sample solvent, in which low ionic solvent was employed as initial mobile phase in the gradient. At last, the analysis of impurities in hydrophobic drug berberine was performed. The results showed that using acidic aqueous methanol as sample solvents could provide high separation efficiency and good resolution (R>1.5).

  3. Simultaneous measurements of solvent dynamics and functional kinetics in a light-activated enzyme.

    PubMed

    Durin, Guillaume; Delaunay, Aude; Darnault, Claudine; Heyes, Derren J; Royant, Antoine; Vernede, Xavier; Hunter, C Neil; Weik, Martin; Bourgeois, Dominique

    2009-03-04

    Solvent fluctuations play a key role in controlling protein motions and biological function. Here, we have studied how individual steps of the reaction catalyzed by the light-activated enzyme protochlorophyllide oxidoreductase (POR) couple with solvent dynamics. To simultaneously monitor the catalytic cycle of the enzyme and the dynamical behavior of the solvent, we designed temperature-dependent UV-visible microspectrophotometry experiments, using flash-cooled nanodroplets of POR to which an exogenous soluble fluorophore was added. The formation and decay of the first two intermediates in the POR-catalyzed reaction were measured, together with the solvent glass transition and the buildup of crystalline ice at cryogenic temperatures. We find that formation of the first intermediate occurs below the glass transition temperature (T(g)), and is not affected by changes in solvent dynamics induced by modifying the glycerol content. In contrast, formation of the second intermediate occurs above T(g) and is influenced by changes in glycerol concentration in a manner remarkably similar to the buildup of crystalline ice. These results suggest that internal, nonslaved protein motions drive the first step of the POR-catalyzed reaction whereas solvent-slaved motions control the second step. We propose that the concept of solvent slaving applies to complex enzymes such as POR.

  4. Automated dynamic headspace organic solvent film microextraction for benzene, toluene, ethylbenzene and xylene. Renewable liquid film as a sampler by a programmable motor.

    PubMed

    Mohammadi, Abdorreza; Alizadeh, Naader

    2006-02-24

    A simple, fast and efficient dynamic headspace-organic solvent film microextraction (DHS-OSFME) method using a new automatic device was developed. The renewable organic films were formed inside a microsyringe barrel using the uniform and repeated movement of the syringe plunger enabled by programmable stirring motor. The plunger speed, number of extraction cycles, and dwell time (stop time after each half round) were controlled by a computer software, which was written by C++ Builder. A theoretical treatment of the DHS-OSFME based on the consecutive first-order process is proposed in this report. A mathematical solution for the dynamic process of the mass transfer was obtained by correlating the variation of analyte concentration in the syringe volume with the plunger speed and the amount of analyte extracted to the OSF. Benzene, toluene, ethylbenzene, and o-xylene (BTEX) were employed as model compounds to assess the extraction procedure and were determined by gas chromatography-flame ionization detection. Of the three organic solvents (1-octanol, benzyl alcohol and n-dodecane) studied as extractants, n-dodecane proved to be the most sensitive solvent for the extraction of these analytes. Several parameters, including the syringe withdrawal rate, dwelling time, number of extraction cycles, sampling volume, sample temperature, and ionic strength of the solution, were investigated for their effects on the extraction performance. The calibration graphs were linear in the range of 0.5-200 ng ml(-1), with the detection limits between 0.18 and 0.35 ng ml(-1). Wastewater samples were extracted by the optimized method, and determined using the standard addition method.

  5. 'GREENER' CHEMICAL SYNTHESES USING MICROWAVES UNDER SOLVENT-FREE CONDITIONS OR AQUEOUS MEDIA

    EPA Science Inventory

    A solvent-free approach that involves microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces is presented which is applicable to a wide range of cleavage, condensation, cycl...

  6. ORGANIC SYNTHESES IN SOLVENT-FREE AND AQUEOUS MEDIA USING MICROWAVES

    EPA Science Inventory

    A solvent-free approach that involves microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces is presented which is applicable to a wide range of cleavage, condensation, cycl...

  7. 'GREENER' ORGANIC SYNTHESES AND TRANSFORMATIONS USING MICROWAVES UNDER SOLVENT-FREE CONDITIONS OR AQUEOUS MEDIA

    EPA Science Inventory

    A solvent-free approach that involves microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces is presented which is applicable to a wide range of cleavage, condensation, cycl...

  8. Solvent recovery system provides timely compliance solution

    SciTech Connect

    1996-11-01

    Hoechst Celanese Corp. (Coventry, Rhode Island) faced the challenge of meeting an Environmental Protection Agency (EPA) deadline for solvent recovery within one year. The company also had to ensure that a new solvent recovery system would satisfy Rhode Island state requirements. An initial search for the required technology was fruitless. Finally, MG Industries (Saint Charles, Missouri), an industrial gas supplier, was chosen for the job. Using CRYOSOLV, as the waste stream cools in the cryogenic condenser (heat exchanger), the solvents condense at temperatures below the dewpoint. The recovered solvent can be recycled into the process, while clean gas is vented to the atmosphere.

  9. Organic solvent use in enterprises in Japan.

    PubMed

    Nagasawa, Yasuhiro; Ukai, Hirohiko; Okamoto, Satoru; Samoto, Hajime; Itoh, Kenji; Moriguchi, Jiro; Sakuragi, Sonoko; Ohashi, Fumiko; Takada, Shiro; Kawakami, Tetsuya; Ikeda, Masayuki

    2011-01-01

    This study was initiated to elucidate possible changes in types of organic solvents (to be called solvents in short) used in enterprises in Japan through comparison of current solvent types with historical data since 1983. To investigate current situation in solvent use in enterprises, surveys were conducted during one year of 2009 to 2010. In total, workroom air samples in 1,497 unit workplaces with solvent use were analyzed in accordance with regulatory requirements. Typical use pattern of solvents was as mixtures, accounting for >70% of cases. Adhesives spreading (followed by adhesion) was relatively common in small-scale enterprises, whereas printing and painting work was more common in middle-scale ones, and solvent use for testing and research purpose was basically in large-scaled enterprises. Through-out printing, painting, surface coating and adhesive application, toluene was most common (being detected in 49 to 82% of workplaces depending on work types), whereas isopropyl alcohol was most common (49%) in degreasing, cleaning and wiping workplaces. Other commonly used solvents were methyl alcohol, ethyl acetate and acetone (33 to 37%). Comparison with historical data in Japan and literature-retrieved data outside of Japan all agreed with the observation that toluene is the most commonly used solvent. Application of trichloroethylene and 1,1,1-trichloroethane, once common in 1980s, has ceased to exist in recent years.

  10. Special Issue: "Organic Reactions in Green Solvents".

    PubMed

    Sperry, Jonathan; García-Álvarez, Joaquín

    2016-11-15

    To overcome the well-established drawbacks of conventional organic solvents (toxicity, non-biodegradability, flammability, accumulation in the atmosphere) remarkable research efforts have been recently devoted to the replacement of traditional organic reaction media by the so-called Green Solvents. In this sense, the choice of a safe, non-toxic, biorenewable and cheap reaction media is a crucial goal in organic synthesis. Thus, this Special Issue on "Organic Reactions in Green Solvents" has been aimed to showcase a series of stimulating contributions from international experts within different sub-areas of organic synthesis in Green Solvents (ranging from metal- to organo-catalyzed organic reactions).

  11. A solvent tolerant isolate of Enterobacter aerogenes.

    PubMed

    Gupta, Anshu; Singh, Rajni; Khare, S K; Gupta, M N

    2006-01-01

    A solvent tolerant strain of Enterobacter aerogenes was isolated from soil by cyclohexane enrichment. Presence of cyclohexane (20%) in culture media prolonged the lag phase and caused reduction in biomass. Transmission electron micrographs showed convoluted cell membrane and accumulation of solvent in case of the cells grown in cyclohexane. The Enterobacter isolate was able to grow in the range of organic solvents having log P above 3.2 and also in presence of mercury, thus showing potential for treatment of solvent rich wastes.

  12. Optimal quantum pumps.

    PubMed

    Avron, J E; Elgart, A; Graf, G M; Sadun, L

    2001-12-03

    We study adiabatic quantum pumps on time scales that are short relative to the cycle of the pump. In this regime the pump is characterized by the matrix of energy shift which we introduce as the dual to Wigner's time delay. The energy shift determines the charge transport, the dissipation, the noise, and the entropy production. We prove a general lower bound on dissipation in a quantum channel and define optimal pumps as those that saturate the bound. We give a geometric characterization of optimal pumps and show that they are noiseless and transport integral charge in a cycle. Finally we discuss an example of an optimal pump related to the Hall effect.

  13. Solvent-driven chemical motor

    NASA Astrophysics Data System (ADS)

    Mitsumata, Tetsu; Ikeda, Kazuo; Gong, Jian Ping; Osada, Yoshihito

    1998-10-01

    A solvent-driven chemical motor using amphiphilic polymer gel has been fabricated. The driving force of the gel originates from the surface tension of spreading organic fluid which is pumped out by osmotic and hydrostatic pressures in the gel. A tetrahydrofurane-swollen gel equipped with a spouting hole made a controlled translational motion with a velocity of 77 mm/s or rotational motion with a maximum speed of 400 rpm and a torque of 10-9-10-7 Nm on the water surface. A generator to produce an electric power with a maximum electromotive force of 15 mV and electric power of 0.2 μW has also been constructed. The successful fabrication of gel motor may produce a new era of soft machine systems which work without pollution and unnecessary intermediates.

  14. Re-construction layer effect of LiNi0.8Co0.15Mn0.05O2 with solvent evaporation process.

    PubMed

    Park, Kwangjin; Park, Jun-Ho; Hong, Suk-Gi; Choi, Byungjin; Heo, Sung; Seo, Seung-Woo; Min, Kyoungmin; Park, Jin-Hwan

    2017-03-20

    The solvent evaporation method on the structural changes and surface chemistry of the cathode and the effect of electrochemical performance of Li1.0Ni0.8Co0.15Mn0.05O2 (NCM) has been investigated. After dissolving of Li residuals using minimum content of solvent in order to minimize the damage of pristine material and the evaporation time, the solvent was evaporated without filtering and remaining powder was re-heated at 700 °C in oxygen environment. Two kinds of solvent, de-ionized water and diluted nitric acid, were used as a solvent. The almost 40% of Li residuals were removed using solvent evaporation method. The NCM sample after solvent evaporation process exhibited an increase in the initial capacity (214.3 mAh/g) compared to the pristine sample (207.4 mAh/g) at 0.1C because of enhancement of electric conductivity caused by decline of Li residuals. The capacity retention of NCM sample after solvent evaporation process (96.0% at the 50th cycle) was also improved compared to that of the pristine NCM sample (90.6% at the 50th cycle). The uniform Li residual layer after solvent treated and heat treatment acted like a coating layer, leading to enhance the cycle performance. The NCM sample using diluted nitric acid showed better performance than that using de-ionized water.

  15. Re-construction layer effect of LiNi0.8Co0.15Mn0.05O2 with solvent evaporation process

    PubMed Central

    Park, Kwangjin; Park, Jun-Ho; Hong, Suk-Gi; Choi, Byungjin; Heo, Sung; Seo, Seung-Woo; Min, Kyoungmin; Park, Jin-Hwan

    2017-01-01

    The solvent evaporation method on the structural changes and surface chemistry of the cathode and the effect of electrochemical performance of Li1.0Ni0.8Co0.15Mn0.05O2 (NCM) has been investigated. After dissolving of Li residuals using minimum content of solvent in order to minimize the damage of pristine material and the evaporation time, the solvent was evaporated without filtering and remaining powder was re-heated at 700 °C in oxygen environment. Two kinds of solvent, de-ionized water and diluted nitric acid, were used as a solvent. The almost 40% of Li residuals were removed using solvent evaporation method. The NCM sample after solvent evaporation process exhibited an increase in the initial capacity (214.3 mAh/g) compared to the pristine sample (207.4 mAh/g) at 0.1C because of enhancement of electric conductivity caused by decline of Li residuals. The capacity retention of NCM sample after solvent evaporation process (96.0% at the 50th cycle) was also improved compared to that of the pristine NCM sample (90.6% at the 50th cycle). The uniform Li residual layer after solvent treated and heat treatment acted like a coating layer, leading to enhance the cycle performance. The NCM sample using diluted nitric acid showed better performance than that using de-ionized water. PMID:28317913

  16. Re-construction layer effect of LiNi0.8Co0.15Mn0.05O2 with solvent evaporation process

    NASA Astrophysics Data System (ADS)

    Park, Kwangjin; Park, Jun-Ho; Hong, Suk-Gi; Choi, Byungjin; Heo, Sung; Seo, Seung-Woo; Min, Kyoungmin; Park, Jin-Hwan

    2017-03-01

    The solvent evaporation method on the structural changes and surface chemistry of the cathode and the effect of electrochemical performance of Li1.0Ni0.8Co0.15Mn0.05O2 (NCM) has been investigated. After dissolving of Li residuals using minimum content of solvent in order to minimize the damage of pristine material and the evaporation time, the solvent was evaporated without filtering and remaining powder was re-heated at 700 °C in oxygen environment. Two kinds of solvent, de-ionized water and diluted nitric acid, were used as a solvent. The almost 40% of Li residuals were removed using solvent evaporation method. The NCM sample after solvent evaporation process exhibited an increase in the initial capacity (214.3 mAh/g) compared to the pristine sample (207.4 mAh/g) at 0.1C because of enhancement of electric conductivity caused by decline of Li residuals. The capacity retention of NCM sample after solvent evaporation process (96.0% at the 50th cycle) was also improved compared to that of the pristine NCM sample (90.6% at the 50th cycle). The uniform Li residual layer after solvent treated and heat treatment acted like a coating layer, leading to enhance the cycle performance. The NCM sample using diluted nitric acid showed better performance than that using de-ionized water.

  17. Determination of organochlorine pesticides and chlorobenzenes in strawberries by using accelerated solvent extraction combined with sorptive enrichment and gas chromatography/mass spectrometry.

    PubMed

    Wennrich, L; Popp, P; Köller, G; Breuste, J

    2001-01-01

    An analytical scheme for the determination of several organochlorine pesticides like hexachlorocyclohexanes (HCHs) and DDX compounds (p,p'-DDE, p,p'-DDD, and p,p'-DDT) as well as chlorobenzenes in strawberries has been developed. The procedure is based on aqueous accelerated solvent extraction (ASE) followed by solid-phase microextraction (SPME) or stir bar sorptive extraction (SBSE) and subsequent thermodesorption-gas chromatography/mass spectrometry analysis. A 65 microm polydimethylsiloxane/ divinylbenzene fiber was chosen for the SPME experiments. Significant SPME and ASE parameters were optimized using spiked water and strawberry samples. For the ASE of the organochlorine compounds, a water-acetone mixture (90 + 10, v/v) as the extraction solvent, an extraction temperature of 120 degrees C, and 2 cycles of 10 min extraction proved optimal. The developed method was evaluated with respect to precision and limits of detection (LOD). The relative standard deviations of replicate ASE-SPME determinations (n = 5) were in the range of 4-24%. LOD values between 1 and 10 microg/kg were achieved with the exception of DDT and DDE (40 microg/kg). Using SBSE, the LOD of these compounds could be improved (2 and 5 microg/kg). The main advantages of this method are the avoidance of cleanup and concentration procedures as well as the significant reduction of the required volume of organic solvents. The described method was applied to the determination of the pollutants in strawberry samples collected from different allotment gardens in a potentially polluted area, the Bitterfeld-Wolfen region (Germany).

  18. Organic solvent-tolerant bacterium which secretes an organic solvent-stable proteolytic enzyme

    SciTech Connect

    Ogino, Hiroyasu; Yasui, Kiyoshi; Shiotani, Takashi

    1995-12-01

    A bacterial strain which can be grown in a medium containing organic solvents and can secrete a proteolytic enzyme was isolated and identified as Pseudomonas aeruginosa. The strain was derived by the following two-step procedures: high proteolytic enzyme producers were first isolated by the usual method, and then the organic solvent-tolerant microorganism was selected from these high-rate proteolytic enzyme producers. The proteolytic activity of the supernatant of the culture was stable in the presence of various organic solvents. The stability of the enzyme in the presence of organic solvents, of which the values of the logarithm of the partition coefficient (log P) were equal to or more than 3.2, was almost the same as that in the absence of organic solvents. It is expected that both the solvent-tolerant microorganism and the solvent-stable enzyme produced by this strain can be used as catalysts for reactions in the presence of organic solvents.

  19. Quantitation of buried contamination by use of solvents. [degradation of silicone polymers by amine solvents

    NASA Technical Reports Server (NTRS)

    Pappas, S. P.; Hsiao, Y. C.; Hill, L. W.

    1973-01-01

    Spore recovery form cured silicone potting compounds using amine solvents to degrade the cured polymers was investigated. A complete list of solvents and a description of the effect of each on two different silicone polymers is provided.

  20. Wide electrochemical window solvents for use in electrochemical devices and electrolyte solutions incorporating such solvents

    DOEpatents

    Angell, Charles Austen; Zhang, Sheng-Shui; Xu, Kang

    1998-01-01

    The present invention relates to electrolyte solvents for use in liquid or rubbery electrolyte solutions. Specifically, this invention is directed to boron-containing electrolyte solvents and boron-containing electrolyte solutions.

  1. Screening method for solvent selection used in tar removal by the absorption process.

    PubMed

    Masurel, Eve; Authier, Olivier; Castel, Christophe; Roizard, Christine

    2015-01-01

    The aim of this paper is the study of the treatment of flue gas issued from a process of biomass gasification in fluidized bed. The flue gas contains tar which should be selectively removed from the fuel components of interest (e.g. H2, CO and light hydrocarbons) to avoid condensation and deposits in internal combustion engine. The chosen flue gas treatment is the gas-liquid absorption using solvents, which present specific physicochemical properties (e.g. solubility, viscosity, volatility and chemical and thermal stability) in order to optimize the unit on energetic, technico-economic and environmental criteria. The rational choice of the proper solvent is essential for solving the tar issue. The preselection of the solvents is made using a Hansen parameter in order to evaluate the tar solubility and the saturation vapour pressure of the solvent is obtained using Antoine law. Among the nine families of screened solvents (alcohols, amines, ketones, halogenates, ethers, esters, hydrocarbons, sulphured and chlorinates), acids methyl esters arise as solvents of interest. Methyl oleate has then been selected and studied furthermore. Experimental liquid-vapour equilibrium data using bubbling point and absorption cell measurements and theoretical results obtained by the UNIFAC-Dortmund model confirm the high potential of this solvent and the good agreement between experimental and theoretical results.

  2. Properties of polylactide inks for solvent-cast printing of three-dimensional freeform microstructures.

    PubMed

    Guo, Shuang-Zhuang; Heuzey, Marie-Claude; Therriault, Daniel

    2014-02-04

    Solvent-cast printing is a highly versatile microfabrication technique that can be used to construct various geometries such as filaments, towers, scaffolds, and freeform circular spirals by the robotic deposition of a polymer solution ink onto a moving stage. In this work, we have performed a comprehensive characterization of the solvent-cast printing process using polylactide (PLA) solutions by analyzing the flow behavior of the solutions, the solvent evaporation kinetics, and the effect of process-related parameters on the crystallization of the extruded filaments. Rotational rheometry at low to moderate shear rates showed a nearly Newtonian behavior of the PLA solutions, while capillary flow analysis based on process-related data indicated shear thinning at high shear rates. Solvent vaporization tests suggested that the internal diffusion of the solvent through the filaments controlled the solvent removal of the extrudates. Different kinds of three-dimensional (3D) structures including a layer-by-layer tower, nine-layer scaffold, and freeform spiral were fabricated, and a processing map was given to show the proper ranges of process-related parameters (i.e., polymer content, applied pressure, nozzle diameter, and robot velocity) for the different geometries. The results of differential scanning calorimetry revealed that slow solvent evaporation could increase the ability of PLA to complete its crystallization process during the filament drying stage. The method developed here offers a new perspective for manufacturing complex structures from polymer solutions and provides guidelines to optimize the various parameters for 3D geometry fabrication.

  3. Fluorosilane compounds with oligo(ethylene oxide) substituent as safe electrolyte solvents for high-voltage lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Wang, Jinglun; Mai, Yongjin; Luo, Hao; Yan, Xiaodan; Zhang, Lingzhi

    2016-12-01

    Two fluorosilanes with oligo(ethylene oxide) unites were synthesized through hydrosilylation of chlorosilane with allyl substituted oligo(ethylene oxide) ether followed by fluorination with potassium fluoride. The synthesized fluorosilane compounds exhibited lower viscosity, higher dielectric constant and higher oxidation potential, compared with their non-fluorination counterparts. Difluoro(3-(2-(2-methoxyethoxy)ethoxy)propyl)methylsilane (DFSM2), one of the two compounds, was evaluated as high-voltage and thermal stable electrolyte co-solvent with the conventional carbonate-based electrolytes. Using an optimized electrolyte of 1M LiPF6 in EC/DFSM2/EMC (2/3/5 in vol.) with addition of 5 wt% fluoroethylene carbonate (FEC), high-voltage LiCoO2(LCO)/graphite full cell displayed outstanding cycling stability of 92.5% capacity retention after 135 cycles at 4.4 V upper cutoff voltage. Characterized by differential scanning calorimetry (DSC) analysis, the DFSM2-based electrolyte demonstrated higher thermal stability with lithiated graphite anode and delithiated LCO cathode, thus better safety feature compared with the conventional electrolyte.

  4. Application of solvent microextraction to the analysis of nitroaromatic explosives in water samples.

    PubMed

    Psillakis, E; Kalogerakis, N

    2001-01-12

    The application of solvent microextraction to the analysis of nitroaromatic explosives is presented. Extraction of 11 nitroaromatics was achieved by suspending 1 microl of organic solvent to the tip of a microsyringe in a stirred aqueous solution. Parameters such as extraction solvent, stirring rate, salt concentration and sampling time were studied and optimized. The limits of detection using bench-top quadrupole mass spectrometry and short extraction times (15 min) were found to be between 0.08 and 1.3 microg/l and the relative standard deviations ranged between 4.3 and 9.8%. Although precision and accuracy of quantification of the method are still needed, solvent microextraction proved to be a fast, simple and inexpensive tool for preconcentration and matrix isolation of nitroaromatics on a microscale.

  5. Wet in situ transesterification of microalgae using ethyl acetate as a co-solvent and reactant.

    PubMed

    Park, Jeongseok; Kim, Bora; Chang, Yong Keun; Lee, Jae W

    2017-04-01

    This study addresses wet in situ transesterification of microalgae for the production of biodiesel by introducing ethyl acetate as both reactant and co-solvent. Ethyl acetate and acid catalyst are mixed with wet microalgae in one pot and the mixture is heated for simultaneous lipid extraction and transesterification. As a single reactant and co-solvent, ethyl acetate can provide higher FAEE yield and more saccharification of carbohydrates than the case of binary ethanol and chloroform as a reactant and a co-solvent. The optimal yield was 97.8wt% at 114°C and 4.06M catalyst with 6.67mlEtOAC/g dried algae based on experimental results and response surface methodology (RSM). This wet in situ transesterification of microalgae using ethyl acetate doesn't require an additional co-solvent and it also promises more economic benefit as combining extraction and transesterification in a single process.

  6. Nile Red staining of phytoplankton neutral lipids: species-specific fluorescence kinetics in various solvents.

    PubMed

    Natunen, Katariina; Seppälä, Jukka; Schwenk, Dagmar; Rischer, Heiko; Spilling, Kristian; Tamminen, Timo

    Nile Red (NR) staining potentially offers a simple method for monitoring lipid accumulation in microalgal cultivation. However, variable staining efficiencies and methods have been reported. The effect of dimethyl sulfoxide (DMSO), ethylene glycol (EG) and glycerol on NR penetration with four different phytoplankton species representing different taxonomical groups was studied. Treatment with the solvents enhanced the NR fluorescence of the diatom Phaeodactylum tricornutum during kinetic fluorescence measurements, but high concentrations of solvents were needed. None of the solvents improved NR staining of the green alga Chlorella pyrenoidosa and Scenedesmus obliquus, which are known to be difficult to stain due to their thick and rigid cell walls. The naked Isochrysis sp. cells stained best without solvents. The results confirm that NR staining protocol needs to be optimized for each species.

  7. Immiscible solvents enabled nanostructure formation for efficient polymer photovoltaic cells.

    PubMed

    Lee, Dong-Hyun; Michael Yang, Yang; You, Jingbi; Richard, Eric; Li, Gang

    2014-07-25

    Organic photovoltaics (OPVs) fabricated via solution processing are an attractive way to realize low cost solar energy harvesting. Bulk heterojunction (BHJ) devices are the most successful design, but their morphology is less controllable. In this manuscript, we describe a simple approach to realize 'ordered' BHJ morphology using two immiscible solvents with different boiling point and a quasi-bilayer approach. Tunable fine structures were demonstrated in poly(3-hexylthiophene) (P3HT) and [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) model systems, and the devices with optimized fine structure showed a 33% efficiency enhancement compared to those with a planar bilayer structure.

  8. Nonlocal Poisson-Fermi model for ionic solvent.

    PubMed

    Xie, Dexuan; Liu, Jinn-Liang; Eisenberg, Bob

    2016-07-01

    We propose a nonlocal Poisson-Fermi model for ionic solvent that includes ion size effects and polarization correlations among water molecules in the calculation of electrostatic potential. It includes the previous Poisson-Fermi models as special cases, and its solution is the convolution of a solution of the corresponding nonlocal Poisson dielectric model with a Yukawa-like kernel function. The Fermi distribution is shown to be a set of optimal ionic concentration functions in the sense of minimizing an electrostatic potential free energy. Numerical results are reported to show the difference between a Poisson-Fermi solution and a corresponding Poisson solution.

  9. Nonlocal Poisson-Fermi model for ionic solvent

    NASA Astrophysics Data System (ADS)

    Xie, Dexuan; Liu, Jinn-Liang; Eisenberg, Bob

    2016-07-01

    We propose a nonlocal Poisson-Fermi model for ionic solvent that includes ion size effects and polarization correlations among water molecules in the calculation of electrostatic potential. It includes the previous Poisson-Fermi models as special cases, and its solution is the convolution of a solution of the corresponding nonlocal Poisson dielectric model with a Yukawa-like kernel function. The Fermi distribution is shown to be a set of optimal ionic concentration functions in the sense of minimizing an electrostatic potential free energy. Numerical results are reported to show the difference between a Poisson-Fermi solution and a corresponding Poisson solution.

  10. Mixed solvent electrolytes for ambient temperature secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Shen, David H. (Inventor); Surampudi, Subbarao (Inventor); Deligiannis, Fotios (Inventor); Halpert, Gerald (Inventor)

    1991-01-01

    The present invention comprises an improved electrolyte for secondary lithium-based cells as well as batteries fabricated using this electrolyte. The electrolyte is a lithium containing salt dissolved in a non-aqueous solvent, which is made from a mixture of ethylene carbonate, ethylene propylene diene terpolymer, 2-methylfuran, and 2-methyltetrahydrofuran. This improved, mixed solvent electrolyte is more conductive than prior electrolytes and much less corrosive to lithium anodes. Batteries constructed with this improved electrolyte utilize lithium or lithium alloy anodes and cathodes made of metal chalcogenides or oxides, such as TiS.sub.2, NbSe.sub.3, V.sub.6 O.sub.13, V.sub.2 O.sub.5, MoS.sub.2, MoS.sub.3, CoO.sub.2, or CrO.sub.2, dissolved in a supporting polymer matrix, like EPDM. The preferred non-aqueous solvent mixture comprises approximately 5 to 30 volume percent ethylene carbonate, approximately 0.01 to 0.1 weight percent ethylene propylene diene terpolymer, and approximately 0.2 to 2 percent 2-methylfuran, with the balance being 2-methyltetrahydrofuran. The most preferred solvent comprises approximately 10 to 20 volume percent ethylene carbonate, about 0.05 weight percent ethylene propylene diene terpolymer, and about 1.0 percent 2-methylfuran, with the balance being 2-methyltetrahydrofuran. The concentration of lithium arsenic hexafluoride can range from about 1.0 to 1.8 M; a concentration 1.5 M is most preferred. Secondary batteries made with the improved electrolyte of this invention have lower internal impedance, longer cycle life, higher energy density, low self-discharge, and longer shelf life.

  11. Fabrication of Janus particles composed of poly (lactic-co-glycolic) acid and hard fat using a solvent evaporation method.

    PubMed

    Matsumoto, Akihiro; Murao, Satoshi; Matsumoto, Michiko; Watanabe, Chie; Murakami, Masahiro

    2016-01-01

    The feasibility of fabricating Janus particles based on phase separation between a hard fat and a biocompatible polymer was investigated. The solvent evaporation method used involved preparing an oil-in-water (o/w) emulsion with a mixture of poly (lactic-co-glycolic) acid (PLGA), hard fat, and an organic solvent as the oil phase and a polyvinyl alcohol aqueous solution as the water phase. The Janus particles were formed when the solvent was evaporated to obtain certain concentrations of PLGA and hard fat in the oil phase, at which phase separation was estimated to occur based on the phase diagram analysis. The hard fat hemisphere was proven to be the oil phase using a lipophilic dye Oil Red O. When the solvent evaporation process was performed maintaining a specific volume during the emulsification process; Janus particles were formed within 1.5 h. However, the formed Janus particles were destroyed by stirring for over 6 h. In contrast, a few Janus particles were formed when enough water to dissolve the oil phase solvent was added to the emulsion immediately after the emulsification process. The optimized volume of the solvent evaporation medium dominantly formed Janus particles and maintained the conformation for over 6 h with stirring. These results indicate that the formation and stability of Janus particles depend on the rate of solvent evaporation. Therefore, optimization of the solvent evaporation rate is critical to obtaining stable PLGA and hard fat Janus particles.

  12. Mechanisms of solute rejection in solvent resistant nanofiltration: the effect of solvent on solute rejection.

    PubMed

    Darvishmanesh, Siavash; Degrève, Jan; Van der Bruggen, Bart

    2010-10-28

    The separation performance of solvent resistant nanofiltration (SRNF) membranes was studied in a systematic way to elucidate the complex mechanisms involved in rejection of solutes. Rejection of three dyes (Sudan II, Sudan Black, Sudan 408) from common organic solvents (methanol, ethanol, acetone, methyl ethyl ketone, toluene and n-hexane) through a polyimide based SRNF membrane, STARMEM™122, was studied. It was found that the rejection of the STARMEM™122 membrane was lower than that indicated by the manufacturer. The experimental observations for Sudan II were not promising for the rejection study as they were lower than expected. Sudan Black and Sudan 408, which are larger solutes than Sudan II, provided more interesting insights. The effects of the solvent on the membrane and solute were studied separately. A higher permeation rate of ketones and alcohols was observed, while permeabilities of non-polar solvents were low which shows that this membrane shows higher affinity toward semi-polar solvents (alcohols, ketones). The effect of the solvent on the solute's rejection, based on the results for Sudan Black and Sudan 408, was studied for solvents in the same chemical groups, since the membrane showed a similar separation performance for solvents with similar functional groups (e.g. alcohols). The effect of solvent on solute molecular size was investigated by using simulation with Molecular Dynamics. It was shown that the effective size of a molecule is dependent on the solvent due to solvation and hydration of the solute by the solvent. The size of the solute in the solvent belonging to a similar family was studied separately. It was clear that the rejection was influenced by molecular size of the solute in the same group of solvents. A surprising negative rejection of solutes was achieved for n-hexane. Although solutes in n-hexane have higher volume compared to those in other solvents, the affinity between the solute and membrane increases the solute

  13. REMEDIATION OF CONTAMINATED SOILS BY SOLVENT FLUSHING

    EPA Science Inventory

    Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. This technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, ...

  14. Coal mining with a liquid solvent

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Miller, C. G.

    1979-01-01

    Study suggests carbonated water can dissolve or suspend coal and carry it to surface. Mixture of carbon dioxide and water may be coal solvent that will make unmanned mining reality. When used with proposed process monitoring coal solubility with conventional strain gage, solvent is basis for rapid cost effective extraction of coal from underground seams.

  15. Remediating pesticide contaminated soils using solvent extraction

    SciTech Connect

    Sahle-Demessie, E.; Meckes, M.C.; Richardson, T.L.

    1996-12-31

    Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p{prime}-DDT, p,p{prime}-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as solvents over a wide range of operating conditions. It was demonstrated that a six-stage methanol extraction using a solvent-to-soil ratio of 1.6 can decrease pesticide levels in the soil by more than 99% and reduce the volume of material requiring further treatment by 25 times or more. The high solubility of the pesticides in methanol resulted in rapid extraction rates, with the system reaching quasi-equilibrium state in 30 minutes. The extraction efficiency was influenced by the number of extraction stages, the solvent-to-soil ratio, and the soil moisture content. Various methods were investigated to regenerate and recycle the solvent. Evaporation and solvent stripping are low cost and reliable methods for removing high pesticide concentrations from the solvent. For low concentrations, GAC adsorption may be used. Precipitating and filtering pesticides by adding water to the methanol/pesticide solution was not successful when tested with soil extracts. 26 refs., 10 figs., 6 tabs.

  16. Cytotoxic effects of gutta-percha solvents.

    PubMed

    Barbosa, S V; Burkard, D H; Spångberg, L S

    1994-01-01

    Cytotoxicity of commonly used gutta-percha solvents was evaluated. Gutta-percha dissolved by chloroform, halothane, or turpentine was evaluated with the radiochromium release method using L929 mouse fibroblast cells. All solvents were toxic. Turpentine was most toxic followed by halothane and chloroform, which caused similar levels of cell injury.

  17. Evaluation of Gutta-percha solvents.

    PubMed

    Kaplowitz, G J

    1990-11-01

    Five solvents (rectified white turpentine, oil of melaleuca, eucalyptol, white pine oil, and pine needle oil) were compared with chloroform for their ability to dissolve gutta-percha. All solvents dissolved at least 50% of the gutta-percha in 15 min at 37 degrees C with chloroform and rectified white turpentine dissolving the gutta-percha completely.

  18. SOLVENT DESIGN UNDER VARYING ENVIRONMENTAL REQUIREMENTS

    EPA Science Inventory

    There is currently a great need to replace many solvents that are commonly used by industry and the public, but whose continued use entails a number of human health and environmental risks. One issue hampering solvent replacement is the general thought that replacement, particul...

  19. Green chemicals: Searching for cleaner solvents

    SciTech Connect

    Lucas, A.

    1994-10-05

    While increased pressure from EPA has solvents producers scrambling to find greener alternatives, many say the cost effectiveness and performance characteristics of traditional technologies are such that they will not disappear quickly. Though a variety of alternative {open_quotes}green{close_quotes} solvents have been developed and commercialized, better means of solvent recovery have also come along, ensuring continued use of many organic solvents. The 1990 Clean Air Act (CAA), designed to eliminate volatile organic compounds (VOCs), ozone depleters, and other hazardous air pollutants (HAPs), has put limits on many organic solvents. Those most under fire are chlorinated solvents, such as methylene chloride, 1,1,1 trichloroethylene (methyl chloroform), and chlorofluorocarbon (CFC)-113. Producers have been developing a variety of lower VOC solvents to replace those being phased out or regulated. Among those likely to experience most growth are aliphatic hydrocarbons to replace chlorinated solvents in cleaning applications. Growth is also expected for alcohols, esters, and glycol ethers for other end-use applications.

  20. REMEDIATING PESTICIDE CONTAMINATED SOILS USING SOLVENT EXTRACTION

    EPA Science Inventory

    Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p'-DDT, p,p'-DDD,, p,p'-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as sol...

  1. A spreadsheet algorithm for stagewise solvent extraction

    SciTech Connect

    Leonard, R.A.; Regalbuto, M.C.

    1993-01-01

    Part of the novelty is the way in which the problem is organized in the spreadsheet. In addition, to facilitate spreadsheet setup, a new calculational procedure has been developed. The resulting Spreadsheet Algorithm for Stagewise Solvent Extraction (SASSE) can be used with either IBM or Macintosh personal computers as a simple yet powerful tool for analyzing solvent extraction flowsheets.

  2. EXPERIENCES IN DESIGNING SOLVENTS FOR THE ENVIRONMENT

    EPA Science Inventory

    Solvents used throughout industry are chosen to meet specific technological requirements such as solute solubility, cleaning and degreasing, or being a medium for paints and coatings. With the increasing awareness of the human health effects and environmental tisks of solvent use...

  3. EXPERIENCES IN DESIGNING SOLVENTS FOR THE ENVIRONMENT

    EPA Science Inventory

    Solvents used throughout industry are chosen to meet specific technological requirements such as solute solubility, cleaning and degreasing, or being a medium for paints and coatings. With the increasing awareness of the human health effects and environmental risks of solvent use...

  4. SOLVENT-FREE ORGANIC SYNTHESES USING MICROWAVES

    EPA Science Inventory

    The latest results on microwave-expedited solvent-free approach as applied to the assembly of organic molecules will be presented. The salient features of this expeditious methodology such as solvent conservation and ease of manipulation etc. will be described in the context of r...

  5. Solvent effect in the Walden inversion reactions

    NASA Astrophysics Data System (ADS)

    Jaume, J.; Lluch, J. M.; Oliva, A.; Bertrán, J.

    1984-04-01

    The solvent effect on the fluoride exchange reaction has been studied by means of ab initio calculations using the 3-21G basis set. It is shown that the motion of the solvent molecules is an important part of the reaction coordinate.

  6. Improved Supercritical-Solvent Extraction of Coal

    NASA Technical Reports Server (NTRS)

    Compton, L.

    1982-01-01

    Raw coal upgraded by supercritical-solvent extraction system that uses two materials instead of one. System achieved extraction yields of 20 to 49 weight percent. Single-solvent yields are about 25 weight percent. Experimental results show extraction yields may be timedependent. Observed decreases in weight of coal agreed well with increases in ash content of residue.

  7. Supercritical-Multiple-Solvent Extraction From Coal

    NASA Technical Reports Server (NTRS)

    Corcoran, W.; Fong, W.; Pichaichanarong, P.; Chan, P.; Lawson, D.

    1983-01-01

    Large and small molecules dissolve different constituents. Experimental apparatus used to test supercritical extraction of hydrogen rich compounds from coal in various organic solvents. In decreasing order of importance, relevant process parameters were found to be temperature, solvent type, pressure, and residence time.

  8. Electrolyte additive enabled fast charging and stable cycling lithium metal batteries

    NASA Astrophysics Data System (ADS)

    Zheng, Jianming; Engelhard, Mark H.; Mei, Donghai; Jiao, Shuhong; Polzin, Bryant J.; Zhang, Ji-Guang; Xu, Wu

    2017-03-01

    Batteries using lithium (Li) metal as anodes are considered promising energy storage systems because of their high energy densities. However, safety concerns associated with dendrite growth along with limited cycle life, especially at high charge current densities, hinder their practical uses. Here we report that an optimal amount (0.05 M) of LiPF6 as an additive in LiTFSI-LiBOB dual-salt/carbonate-solvent-based electrolytes significantly enhances the charging capability and cycling stability of Li metal batteries. In a Li metal battery using a 4-V Li-ion cathode at a moderately high loading of 1.75 mAh cm‑2, a cyclability of 97.1% capacity retention after 500 cycles along with very limited increase in electrode overpotential is accomplished at a charge/discharge current density up to 1.75 mA cm‑2. The fast charging and stable cycling performances are ascribed to the generation of a robust and conductive solid electrolyte interphase at the Li metal surface and stabilization of the Al cathode current collector.

  9. Thermoplastic composite matrices with improved solvent resistance

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.; Jensen, B. J.; Havens, S. J.

    1984-01-01

    In order to improve solvent resistance of aromatic thermoplastic polymers, ethynyl-terminated aromatic sulfone polymers (ETS), sulfone/ester polymers (SEPE) containing pendent ethynyl groups, and phenoxy resin containing pendent ethynyl groups are synthesized. Cured polysulfones and phenoxy resins containing ethynyl groups on the ends or pendent on the molecules exhibited systematic behavior in solvent resistance, film flexibility, and toughness as a function of crosslink density. The film and composite properties of a cured solvent-resistant ETS were better than those of a commercially available solvent sensitive polysulfone. The study was part of a NASA program to better understand the trade-offs between solvent resistance, processability and mechanical properties which may be useful in designing composite structures for aerospace vehicles.

  10. METHOD FOR SOLVENT-ISOSTATIC PRESSING

    DOEpatents

    Archibald, P.B.

    1962-09-18

    This invention provides a method for producing densely compacted bodies having relatively large dimensions. The method comprises the addition of a small quantity of a suitable solvent to a powder which is to be compacted. The solvent- moistened powder is placed inside a flexible bag, and the bag is suspended in an isostatic press. The solvent is squeezed out of the powder by the isostatic pressure, and the resulting compacted body is recovered. The presence of the solvent markedly decreases the proportion of void space in the powder, thereby resulting in a denser, more homogeneous compact. Another effect of the solvent is that it allows the isostatic pressing operation to be conducted at substantially lower pressures than are conventionally employed. (AEC)

  11. Stabilization of Underground Solvent Storage Tanks

    SciTech Connect

    Smail, T.R.

    2003-08-15

    The Old Solvent Tanks (OST), located at the Savannah River Site (SRS) are comprised of 22 underground storage tanks that were used to store spent radioactive solvent and aqueous wastes generated from the plutonium-uranium extraction (PUREX) process. The OSTs were installed at various dates between 1955 and 1968 and used to store the spent solvents until 1974. The spent solvents stored in the OSTs were transferred out from 1976 through 1981 leaving only residual liquids and sludges that could not be pumped out.Final remediation goals include an overlying infiltration control system. If the tanks were to structurally fail, they would collapse causing potential for onsite worker exposure and release of tank contents to the environment. Therefore, as an interim action, methods for stabilizing the tanks were evaluated. This paper will discuss the systems designed to perform and monitor the grouting operation, the grouting process, and the radiological controls and wastes associated with grouting the Old Solvent Tanks.

  12. SOLVENT DISPERSION AND FLOW METER CALCULATION RESULTS

    SciTech Connect

    Nash, C.; Fondeur, F.; Peters, T.

    2013-06-21

    Savannah River National Laboratory (SRNL) found that the dispersion numbers for the six combinations of CSSX:Next Generation Solvent (NGS) “blend” and pure NGS versus salt solution, caustic wash, and strip aqueous solutions are all good. The dispersion numbers are indications of processability with centrifugal contactors. A comparison of solvent physical and thermal properties shows that the Intek™ solvent flow meter in the plant has a reading biased high versus calibrated flow when NGS is used, versus the standard CSSX solvent. The flow meter, calibrated for CSSX solvent, is predicted to read 2.8 gpm of NGS in a case where the true flow of NGS is 2.16 gpm.

  13. Assessment of solvents for cellulose dissolution.

    PubMed

    Ghasemi, Mohammad; Tsianou, Marina; Alexandridis, Paschalis

    2017-03-01

    A necessary step in the processing of biomass is the pretreatment and dissolution of cellulose. A good solvent for cellulose involves high diffusivity, aggressiveness in decrystallization, and capability of disassociating the cellulose chains. However, it is not clear which of these factors and under what conditions should be improved in order to obtain a more effective solvent. To this end, a newly-developed phenomenological model has been applied to assess the controlling mechanism of cellulose dissolution. Among the findings, the cellulose fibers remain crystalline almost to the end of the dissolution process for decrystallization-controlled kinetics. In such solvents, decreasing the fiber crystallinity, e.g., via pretreatment, would result in a considerable increase in the dissolution rate. Such insights improve the understanding of cellulose dissolution and facilitate the selection of more efficient solvents and processing conditions for biomass. Specific examples of solvents are provided where dissolution is limited due to decrystallization or disentanglement.

  14. Toxic hepatitis in occupational exposure to solvents

    PubMed Central

    Malaguarnera, Giulia; Cataudella, Emanuela; Giordano, Maria; Nunnari, Giuseppe; Chisari, Giuseppe; Malaguarnera, Mariano

    2012-01-01

    The liver is the main organ responsible for the metabolism of drugs and toxic chemicals, and so is the primary target organ for many organic solvents. Work activities with hepatotoxins exposures are numerous and, moreover, organic solvents are used in various industrial processes. Organic solvents used in different industrial processes may be associated with hepatotoxicity. Several factors contribute to liver toxicity; among these are: species differences, nutritional condition, genetic factors, interaction with medications in use, alcohol abuse and interaction, and age. This review addresses the mechanisms of hepatotoxicity. The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are: inflammation, dysfunction of cytochrome P450, mitochondrial dysfunction and oxidative stress. The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work. PMID:22719183

  15. Life cycle assessment of biodiesel production from algal bio-crude oils extracted under subcritical water conditions.

    PubMed

    Ponnusamy, Sundaravadivelnathan; Reddy, Harvind Kumar; Muppaneni, Tapaswy; Downes, Cara Meghan; Deng, Shuguang

    2014-10-01

    A life cycle assessment study is performed for the energy requirements and greenhouse gas emissions in an algal biodiesel production system. Subcritical water (SCW) extraction was applied for extracting bio-crude oil from algae, and conventional transesterification method was used for converting the algal oil to biodiesel. 58MJ of energy is required to produce 1kg of biodiesel without any co-products management, of which 36% was spent on cultivation and 56% on lipid extraction. SCW extraction with thermal energy recovery reduces the energy consumption by 3-5 folds when compared to the traditional solvent extraction. It is estimated that 1kg of algal biodiesel fixes about 0.6kg of CO2. An optimized case considering the energy credits from co-products could further reduce the total energy demand. The energy demand for producing 1kg of biodiesel in the optimized case is 28.23MJ.

  16. Enhanced solvent extraction of polar lipids associated with rubber particles from Hevea brasiliensis.

    PubMed

    Bonfils, Frederic; Ehabe, Eugene Ejolle; Aymard, Christian; Vaysse, Laurent; Sainte-Beuve, Jerome

    2007-01-01

    Biochemical studies of lipids bound to rubber particles have been complicated due to the solubility of polyisoprene chains in most extracting solvents and the rather delicate nature of polar lipids that are often denatured when traditional solvent extraction techniques are employed. In this paper, we describe a traditional technique and accompanying solvents that permit optimal extraction of rubber particle bound lipids. The technique, which is validated after characterizing the lipid extracts by elemental analysis, silica column adsorption and thin layer chromatography, appeared more suitable for extracting total lipids with optimal glycolipid and phospholipid contents. This technique is proposed as an alternative to traditional extraction methods used for solid natural rubber as it offers advantages with respect to ease of application, extract quality, extraction yields and reproducibility.

  17. PARIS II: Computer Aided Solvent Design for Pollution Prevention

    EPA Science Inventory

    This product is a summary of U.S. EPA researchers' work developing the solvent substitution software tool PARIS II (Program for Assisting the Replacement of Industrial Solvents, version 2.0). PARIS II finds less toxic solvents or solvent mixtures to replace more toxic solvents co...

  18. Experiment on the treatment of waste extraction solvent from the molybdenum-99 process

    SciTech Connect

    Hsien-Ming Hsiao; Chang-Liang Hu; Kuang-Li Chien; Wen-Cheng Lee; Tsong-Yang Wei

    2013-07-01

    In the Mo-99 (Molybdenum-99) isotope extraction test process for radiopharmaceutical applications, organic solvent is used to extract Mo-99 from an irradiated UO{sub 2} dissolution. The extraction solvent was stored when the test work was stopped. A total of about 120 liters of waste solvent was stored at INER (Institute of Nuclear Energy Research, Taiwan). The extraction solvent consisted of 5% di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and kerosene. The radionuclides found in the waste solvent include Cs-137, Am-241, Tc-99, and Sr-90, which give off gross alpha and beta radioactivity of 1898 and 471 Bq/ml, respectively. This study aims to remove radionuclides from the waste solvent using sodium carbonate and sodium hydroxide solutions in different concentrations. After mixing the waste solvent with the alkaline solution followed by settling, a third phase other than organic and aqueous phase appeared which is expected due to the saponification reaction. The experimental results showed that increasing the number of washing and the alkaline solution concentration could enhance the radionuclides removal rate. An optimal removal method was proposed using 2 M Na{sub 2}CO{sub 3} solution twice followed by 1 M NaOH solution one time for the third phase generated early in the mixing stages. The remaining gross alpha and beta radioactivity of the treated organic solvent was 2 and 3 Bq/ml, respectively. The treated solvent could be stabilized by ashing at 500 deg. C and then immobilized. The alkaline solution would be neutralized by hydrochloric or nitric acid and then treated using a variety of adsorbents or bone char via adsorption to remove nuclides to meet the wastewater discharge limitation. (authors)

  19. ACCELERATED SOLVENT EXTRACTION COMBINED WITH ...

    EPA Pesticide Factsheets

    A research project was initiated to address a recurring problem of elevated detection limits above required risk-based concentrations for the determination of semivolatile organic compounds in high moisture content solid samples. This project was initiated, in cooperation with the EPA Region 1 Laboratory, under the Regional Methods Program administered through the ORD Office of Science Policy. The aim of the project was to develop an approach for the rapid removal of water in high moisture content solids (e.g., wetland sediments) in preparation for analysis via Method 8270. Alternative methods for water removal have been investigated to enhance compound solid concentrations and improve extraction efficiency, with the use of pressure filtration providing a high-throughput alternative for removal of the majority of free water in sediments and sludges. In order to eliminate problems with phase separation during extraction of solids using Accelerated Solvent Extraction, a variation of a water-isopropanol extraction method developed at the USGS National Water Quality Laboratory in Denver, CO is being employed. The concentrations of target compounds in water-isopropanol extraction fluids are subsequently analyzed using an automated Solid Phase Extraction (SPE)-GC/MS method developed in our laboratory. The coupled approaches for dewatering, extraction, and target compound identification-quantitation provide a useful alternative to enhance sample throughput for Me

  20. The NEWS Water Cycle Climatology

    NASA Technical Reports Server (NTRS)

    Rodell, Matthew; Beaudoing, Hiroko Kato; L'Ecuyer, Tristan; William, Olson

    2012-01-01

    NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

  1. Towards more thermally stable Li-ion battery electrolytes with salts and solvents sharing nitrile functionality

    NASA Astrophysics Data System (ADS)

    Kerner, Manfred; Lim, Du-Hyun; Jeschke, Steffen; Rydholm, Tomas; Ahn, Jou-Hyeon; Scheers, Johan

    2016-11-01

    The overall safety of Li-ion batteries is compromised by the state-of-the-art electrolytes; the thermally unstable lithium salt, lithium hexafluorophosphate (LiPF6), and flammable carbonate solvent mixtures. The problem is best addressed by new electrolyte compositions with thermally robust salts in low flammability solvents. In this work we introduce electrolytes with either of two lithium nitrile salts, lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA) or lithium 4,5-dicyano-2-trifluoromethylimidazolide (LiTDI), in solvent mixtures with high flashpoint adiponitrile (ADN), as the main component. With sulfolane (SL) and ethylene carbonate (EC) as co-solvents the liquid temperature range of the electrolytes are extended to lower temperatures without lowering the flashpoint, but at the expense of high viscosities and moderate ionic conductivities. The anodic stabilities of the electrolytes are sufficient for LiFePO4 cathodes and can be charged/discharged for 20 cycles in Li/LiFePO4 cells with coulombic efficiencies exceeding 99% at best. The excellent thermal stabilities of the electrolytes with the solvent combination ADN:SL are promising for future electrochemical investigations at elevated temperatures (> 60 °C) to compensate the moderate transport properties and rate capability. The electrolytes with EC as a co-solvent, however, release CO2 by decomposition of EC in presence of a lithium salt, which potentially makes EC unsuitable for any application targeting higher operating temperatures.

  2. CO{sub 2}-philic oligomers as novel solvents for CO{sub 2} absorption

    SciTech Connect

    Miller, Matthew B; Luebke, David R; Enick, Robert M

    2010-01-01

    Desirable properties for an oligomeric CO{sub 2}-capture solvent in an integrated gasification combined cycle (IGCC) plant include high selectivity for CO{sub 2} over H{sub 2} and water, low viscosity, low vapor pressure, low cost, and minimal environmental, health, and safety impacts. The neat solvent viscosity and solubility of CO{sub 2}, measured via bubble-point loci and presented on a pressure−composition diagram (weight basis), and water miscibility in CO{sub 2}-philic solvents have been determined and compared to results obtained with Selexol, a commercial oligomeric CO{sub 2} solvent. The solvents tested include polyethyleneglycol dimethylether (PEGDME), polypropyleneglycol dimethylether (PPGDME), polypropyleneglycol diacetate (PPGDAc), polybutyleneglycol diacetate (PBGDAc), polytetramethyleneetherglycol diacetate (PTMEGDAc), glyceryl triacetate (GTA), polydimethyl siloxane (PDMS), and perfluorpolyether (PFPE) that has a perfluorinated propyleneglycol monomer unit. Overall, PDMS and PPGDME are the best oligomeric solvents tested and exhibit properties that make them very promising alternatives for the selective absorption of CO{sub 2} from a mixed gas stream, especially if the absorption of water is undesirable.

  3. Organic aqueous tunable solvents (OATS): a vehicle for coupling reactions and separations.

    PubMed

    Pollet, Pamela; Hart, Ryan J; Eckert, Charles A; Liotta, Charles L

    2010-09-21

    In laboratory-based chemical synthesis, the choice of the solvent and the means of product purification are rarely determined by cost or environmental impact considerations. When a reaction is scaled up for industrial applications, however, these choices are critical: the separation of product from the solvent, starting materials, and byproduct usually constitutes 60-80% of the overall cost of a process. In response, researchers have developed solvents and solvent-handling methods to optimize both the reaction and the subsequent separation steps on the manufacturing scale. These include "switchable" solvents, which are designed so that their physical properties can be changed abruptly, as well as "tunable" solvents, wherein the solvent's properties change continuously through the application of an external stimulus. In this Account, we describe the organic aqueous tunable solvent (OATS) system, examining two instructive and successful areas of application of OATS as well as its clear potential for further refinement. OATS systems address the limitations of biphasic processes by optimizing reactions and separations simultaneously. The reaction is performed homogeneously in a miscible aqueous-organic solvent mixture, such as water-tetrahydrofuran (THF). The efficient product separation is conducted heterogeneously by the simple addition of modest pressures of CO(2) (50-60 bar) to the system. Under these conditions, the water-THF phase splits into two relatively immiscible phases: the organic THF phase contains the hydrophobic product, and the aqueous phase contains the hydrophilic catalyst. We take advantage of the unique properties of OATS to develop environmentally benign and cost-competitive processes relevant in industrial applications. Specifically, we describe the use of OATS for optimizing the reaction, separation, design, and recycling of (i) Rh-catalyzed hydroformylation of olefins such as 1-octene and (ii) enzyme-catalyzed hydrolysis of 2-phenylacetate. We

  4. Differential response of marine diatoms to solvents

    SciTech Connect

    Tadros, M.G.; Phillips, J.; Patel, H.; Pandiripally, V.

    1995-06-01

    Unicellular algae in aquatic ecosystems are subjected to a variety of pollutants from sources such as runoff from agricultural lands and industrial outfalls. Organic solvents are natural components of oil deposits and commonly find their way into surface waters as a result of discharges from refineries, waste oil, disposal, and accidental spills. Organic solvents can make their way into the environment as industrial wastes. Because of their carcinogenic potential, contamination of soil and water by solvents is cause for serious concern. Relatively few reports have been published on the comparative toxicity of solvents towards test organisms, and these dealt primarily with fish and aquatic invertebrates. However, only few data of toxicity effects of solvents on algae have been published. Phytoplankton species vary in their tolerance to trace metals. Diatoms in particular are able to detoxify trace metals by the excretion of organic compounds. A previous study reported that diatoms collected form different sites in the Gulf of Mexico varied in their physiological characteristics. Algae have been considered to be good indicator s of bioactivity of industrial wastes. Unicellular algae vary in their response to a variety of toxicants. Little is known, however, about toxicity of solvents to marine diatoms. The work reported here was done to examine the effect of selected solvents on seven diatom species to determine whether they differed in their responses to these chemicals. 16 refs., 1 fig.

  5. Organic Solvent Tolerant Lipases and Applications

    PubMed Central

    Kanwar, Shamsher S.

    2014-01-01

    Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s) could be performed in water-restricted organic media as organic solvent(s) not only improve(s) the solubility of substrate and reactant in reaction mixture but also permit(s) the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented. PMID:24672342

  6. Polar Solvents Trigger Formation of Reverse Micelles.

    PubMed

    Khoshnood, Atefeh; Firoozabadi, Abbas

    2015-06-09

    We use molecular dynamics simulations and molecular thermodynamics to investigate the formation of reverse micelles in a system of surfactants and nonpolar solvents. Since the early observation of reverse micelles, the question has been whether the existence of polar solvent molecules such as water is the driving force for the formation of reverse micelles in nonpolar solvents. In this work, we use a simple coarse-grained model of surfactants and solvents to show that a small number of polar solvent molecules triggers the formation of large permanent aggregates. In the absence of polar molecules, both the thermodynamic model and molecular simulations show that small aggregates are more populated in the solution and larger ones are less frequent as the system evolves over time. The size and shape of reverse micelles depend on the size of the polar core: the shape is spherical for a large core and ellipsoidal for a smaller one. Using the coarse-grained model, we also investigate the effect of temperature and surfactant tail length. Our results reveal that the number of surfactant molecules in the micelle decreases as the temperature increases, but the average diameter does not change because the size of the polar core remains invariant. A reverse micelle with small polar core attracts fewer surfactants when the tail is long. The uptake of solvent particles by a micelle of longer surfactant tail is less than shorter ones when the polar solvent particles are initially distributed randomly.

  7. Solvent Effect on the Photolysis of Riboflavin.

    PubMed

    Ahmad, Iqbal; Anwar, Zubair; Ahmed, Sofia; Sheraz, Muhammad Ali; Bano, Raheela; Hafeez, Ambreen

    2015-10-01

    The kinetics of photolysis of riboflavin (RF) in water (pH 7.0) and in organic solvents (acetonitrile, methanol, ethanol, 1-propanol, 1-butanol, ethyl acetate) has been studied using a multicomponent spectrometric method for the assay of RF and its major photoproducts, formylmethylflavin and lumichrome. The apparent first-order rate constants (k obs) for the reaction range from 3.19 (ethyl acetate) to 4.61 × 10(-3) min(-1) (water). The values of k obs have been found to be a linear function of solvent dielectric constant implying the participation of a dipolar intermediate along the reaction pathway. The degradation of this intermediate is promoted by the polarity of the medium. This indicates a greater stabilization of the excited-triplet states of RF with an increase in solvent polarity to facilitate its reduction. The rate constants for the reaction show a linear relation with the solvent acceptor number indicating the degree of solute-solvent interaction in different solvents. It would depend on the electron-donating capacity of RF molecule in organic solvents. The values of k obs are inversely proportional to the viscosity of the medium as a result of diffusion-controlled processes.

  8. Environmental Impacts on Nuclear Reprocessing Solvents

    NASA Astrophysics Data System (ADS)

    Gillens, A. R.; Fessenden, J. E.

    2009-12-01

    Nuclear tests have been employed ever since the first nuclear explosion in Alamogordo, NM during the mid-1940s. Nuclear weapons pose a threat to civil society and result in extensive biological (medical) damages. For this reason, treaties banning nuclear tests and weapons have been employed since the 1960s to cease proliferation of weapons. However, as nuclear tests continue in secrecy and actinides, such as plutonium and uranium, are eligible for theft, nuclear forensics is needed to prevent weapons proliferation. In this study, solvents [tributyl phosphate (TBP), dodecane, decanol] used in reprocessing spent nuclear fuel are analyzed using an isotope ratio mass spectrometer, which provides indisputable evidence in identifying the operation in which solvents were used. Solvent samples are observed under variable conditions in the laboratory for different time periods. It is assumed that their carbon isotope values (δ13C) will become more positive (shift heavy) with time. It is found that the solvents are hygroscopic. TBP leaves the most robust signature compared to the other solvents studied and the isotope values for all solvents under all conditions become more positive with time. This study serves as primary research in understanding how solvents behave under variable conditions in the laboratory and how this could be translated to the environment in fate and transport studies.

  9. Optimization of Pressurized Liquid Extraction of Three Major Acetophenones from Cynanchum bungei Using a Box-Behnken Design

    PubMed Central

    Li, Wei; Zhao, Li-Chun; Sun, Yin-Shi; Lei, Feng-Jie; Wang, Zi; Gui, Xiong-Bin; Wang, Hui

    2012-01-01

    In this work, pressurized liquid extraction (PLE) of three acetophenones (4-hydroxyacetophenone, baishouwubenzophenone, and 2,4-dihydroxyacetophenone) from Cynanchum bungei (ACB) were investigated. The optimal conditions for extraction of ACB were obtained using a Box-Behnken design, consisting of 17 experimental points, as follows: Ethanol (100%) as the extraction solvent at a temperature of 120 °C and an extraction pressure of 1500 psi, using one extraction cycle with a static extraction time of 17 min. The extracted samples were analyzed by high-performance liquid chromatography using an UV detector. Under this optimal condition, the experimental values agreed with the predicted values by analysis of variance. The ACB extraction yield with optimal PLE was higher than that obtained by soxhlet extraction and heat-reflux extraction methods. The results suggest that the PLE method provides a good alternative for acetophenone extraction. PMID:23203079

  10. Role of solvents on the oxygen reduction and evolution of rechargeable Li-O2 battery

    NASA Astrophysics Data System (ADS)

    Christy, Maria; Arul, Anupriya; Zahoor, Awan; Moon, Kwang Uk; Oh, Mi Young; Stephan, A. Manuel; Nahm, Kee Suk

    2017-02-01

    The choice of electrolyte solvent is expected to play a key role in influencing the lithium-oxygen battery performance. The electrochemical performances of three electrolytes composed of lithium bis (trifluoromethane sulfonyl) imide (LiTFSI) salt and different solvents namely, ethylene carbonate/propylene carbonate (EC/PC), tetra ethylene glycol dimethyl ether (TEGDME) and dimethyl sulfoxide (DMSO) are investigated by assembling lithium oxygen cells. The electrolyte composition significantly varied the specific capacity of the battery. The choice of electrolyte also influences the overpotential, cycle life, and rechargeability of the battery. Electrochemical impedance spectra, cyclic voltammetry, and chronoamperometry were utilized to determine the reversible reactions associated with the air cathode.

  11. THE DESIGN OF TECHNOLOGICALLY EFFECTIVE AND ENVIRONMENTALLY BENIGN SOLVENT SUBSTITUTES

    EPA Science Inventory

    There is presently considerable interest in finding environmentally benign replacement solvents that can perform in many different applications as solvents normally do. This requires solvents with desirable properties, e.g., ability to dissolve certain compounds, and without oth...

  12. Effect of pH and lactose concentration on solvent production from whey permeate using Clostridium acetobutylicum

    SciTech Connect

    Ennis, B.M.; Maddox, I.S.

    1987-02-20

    A study was performed to optimize the production of solvents from whey permeate in batch fermentation using Clostridium acetobutylicum P262. Fermentations performed at relatively low pH values resulted in high solvent yields and productivities, but lactose utilization was incomplete. At higher pH values, lactose-utilization was improved but acid production dominated over solvent production. When operating at the higher pH values, an increase in the initial lactose concentration of the whey permeate resulted in lower rates of lactose utilization, and this was accompanied by increased solvent production and decreased acid production. Analysis of data from several experiments revealed a strong inverse relationship between solvent yield and lactose utilization rate. Thus, conditions which minimize the lactose utilization rate such as low culture pH values or high initial lactose concentrations, favor solventogenesis at the expense of acid production. 12 references.

  13. Enzymatic biodiesel production kinetics using co-solvent and an anhydrous medium: a strategy to improve lipase performance in a semi-continuous reactor.

    PubMed

    Azócar, Laura; Navia, Rodrigo; Beroiz, Leticia; Jeison, David; Ciudad, Gustavo

    2014-09-25

    Enzymatic biodiesel production kinetics under previously optimized conditions were investigated. Waste frying oil (WFO) was used as the raw material, Novozym 435 as catalyst, methanol as acyl acceptor and tert-butanol as co-solvent. To investigate pure transesterification kinetics improving product properties, 3Å molecular sieves were incorporated into the reaction to provide an anhydrous medium avoiding the side reactions of hydrolysis and esterification. The effects of either WFO or methanol on the reaction rate were analyzed separately. The reaction was described by a Ping Pong mechanism and competitive inhibition by methanol. The results obtained in the kinetics study were applied in the operation of a semi-continuous reactor for biodiesel production. The operational conditions of each reaction cycle were: methanol-to-oil ratio 8/1 (mol/mol), 15% (wt) Novozym 435, 0.75% (v/v) of tert-butanol, 44.5°C, 200 rpm and 4h of reaction time. The enzymes were successively reused by remaining in the reactor during all the cycles. Under these conditions, biodiesel production yields higher than 80% over 7 reaction cycles were observed. Both the kinetics study and the reactor operation showed that Novozym 435 was not inhibited at high methanol concentrations and that the kinetics of the proposed enzymatic process could be comparable to the conventional chemical process.

  14. Genomic and Genetic Approaches to Solvent Tolerance

    SciTech Connect

    Eleftherios T. Papoutsakis

    2005-06-10

    The proposed research is to understand and exploit the molecular basis that determines tolerance of the industrially important anaerobic clostridia to solvents. Furthermore, we aim to develop general genomic and metabolic engineering strategies for understanding the molecular basis of tolerance to chemicals and for developing tolerant strains. Our hypothesis is that the molecular basis of what makes bacterial cells able to withstand high solvent concentrations can be used to metabolically engineer cells so that they can tolerate higher concentrations of solvents and related chemicals.

  15. Exploring Hamiltonian dielectric solvent molecular dynamics

    NASA Astrophysics Data System (ADS)

    Bauer, Sebastian; Tavan, Paul; Mathias, Gerald

    2014-09-01

    Hamiltonian dielectric solvent (HADES) is a recent method [7,25], which enables Hamiltonian molecular dynamics (MD) simulations of peptides and proteins in dielectric continua. Sample simulations of an α-helical decapeptide with and without explicit solvent demonstrate the high efficiency of HADES-MD. Addressing the folding of this peptide by replica exchange MD we study the properties of HADES by comparing melting curves, secondary structure motifs and salt bridges with explicit solvent results. Despite the unoptimized ad hoc parametrization of HADES, calculated reaction field energies correlate well with numerical grid solutions of the dielectric Poisson equation.

  16. A Spreadsheet Algorithm for Stagewise Solvent Extraction

    SciTech Connect

    Leonard, R.A.; Regalbuto, M.C.

    1993-08-01

    The material balance and equilibrium equations for solvent extraction processes have been combined with computer spreadsheets in a new way so that models for very complex multicomponent multistage operations can be setup and used easily. A part of the novelty is the way in which the problem is organized in the spreadsheet. In addition, to facilitate spreadsheet setup, a new calculational procedure has been developed. The resulting Spreadsheet Algorithm for Stagewise Solvent Extraction (SASSE) can be used with either IBM or Macintosh personal computers as a simple yet powerful tool for analyzing solvent extraction flowsheets.

  17. What makes critical-solvent processes work

    SciTech Connect

    Brule, M.R.; Corbett, R.W.

    1984-06-01

    Critical-solvent processing (sometimes called supercritical-gas extraction) is an ongoing technology based on phase-equilibrium phenomena in the critical region. Many new practical applications of critical-solvent processing are being conceived and implemented in the food, drug and chemical industries. The advantages afforded by critical-solvent processing in performing difficult separations such as caffeine from coffee, nicotine from tobacco, chemotherapeutic drugs from plants, and chemical feedstocks from petroleum and synfuels residua have been realized just in the last decade or so.

  18. Switchable solvents and methods of use thereof

    DOEpatents

    Jessop, Philip G.; Eckert, Charles A.; Liotta, Charles L.; Heldebrant, David J.

    2013-08-20

    A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

  19. Switchable solvents and methods of use thereof

    DOEpatents

    Jessop, Philip G; Eckert, Charles A; Liotta, Charles L; Heldebrant, David J

    2014-04-29

    A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

  20. Switchable solvents and methods of use thereof

    DOEpatents

    Jessop, Philip G.; Eckert, Charles A.; Liotta, Charles L.; Heldebrant, David J.

    2011-07-19

    A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

  1. Firing of pulverized solvent refined coal

    DOEpatents

    Lennon, Dennis R.; Snedden, Richard B.; Foster, Edward P.; Bellas, George T.

    1990-05-15

    A burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired successfully without any performance limitations and without the coking of the solvent refined coal on the burner components. The burner is provided with a tangential inlet of primary air and pulverized fuel, a vaned diffusion swirler for the mixture of primary air and fuel, a center water-cooled conical diffuser shielding the incoming fuel from the heat radiation from the flame and deflecting the primary air and fuel steam into the secondary air, and a watercooled annulus located between the primary air and secondary air flows.

  2. Physics challenges for advanced fuel cycle assessment

    SciTech Connect

    Giuseppe Palmiotti; Massimo Salvatores; Gerardo Aliberti

    2014-06-01

    Advanced fuel cycles and associated optimized reactor designs will require substantial improvements in key research area to meet new and more challenging requirements. The present paper reviews challenges and issues in the field of reactor and fuel cycle physics. Typical examples are discussed with, in some cases, original results.

  3. Interaction of organic solvents with protein structures at protein-solvent interface.

    PubMed

    Khabiri, Morteza; Minofar, Babak; Brezovský, Jan; Damborský, Jiří; Ettrich, Rudiger

    2013-11-01

    The effect of non-denaturing concentrations of three different organic solvents, formamide, acetone and isopropanol, on the structure of haloalkane dehalogenases DhaA, LinB, and DbjA at the protein-solvent interface was studied using molecular dynamics simulations. Analysis of B-factors revealed that the presence of a given organic solvent mainly affects the dynamical behavior of the specificity-determining cap domain, with the exception of DbjA in acetone. Orientation of organic solvent molecules on the protein surface during the simulations was clearly dependent on their interaction with hydrophobic or hydrophilic surface patches, and the simulations suggest that the behavior of studied organic solvents in the vicinity of hyrophobic patches on the surface is similar to the air/water interface. DbjA was the only dimeric enzyme among studied haloalkane dehalogenases and provided an opportunity to explore effects of organic solvents on the quaternary structure. Penetration and trapping of organic solvents in the network of interactions between both monomers depends on the physico-chemical properties of the organic solvents. Consequently, both monomers of this enzyme oscillate differently in different organic solvents. With the exception of LinB in acetone, the structures of studied enzymes were stabilized in water-miscible organic solvents.

  4. An investigation of solute-solvent interactions in binary liquid mixtures of 3'-methoxyacetophenone: using Raman spectroscopy and DFT calculations.

    PubMed

    Yamini, D; Ramakrishnan, V

    2013-07-01

    Raman spectral measurements have been carried out for neat 3'-methoxy acetophenone (3'-MAP) and binary liquid mixtures of 3'-MAP in three solvents of different polarity. Also Density Functional Theory (DFT) geometry optimization and vibrational wavenumber calculation have been performed on monomer and dimer structures of 3'-MAP to analyze the experimentally observed Raman spectrum. Mulliken charge analysis has also been made on optimized geometries of 3'-MAP with solvents. The changes associated with the observed peak position, intensity and linewidth in the carbonyl stretching mode of 3'-MAP are explained as a consequence of intermolecular interactions between solute-solute and solute-solvent molecules. This analysis reports that the solute-solvent interaction is dominant in the case of binary liquid mixtures of 3'-MAP with ethanol compared to DMF and benzene.

  5. Determination of organochlorine pesticides in snow water samples by low density solvent based dispersive liquid-liquid microextraction.

    PubMed

    Zhao, Wenting; Li, Jindong; Wu, Tong; Wang, Peng; Zhou, Zhiqiang

    2014-09-01

    A simple, rapid, efficient, and environmentally friendly pretreatment based on a low-density solvent based dispersive liquid-liquid microextraction was developed for determining trace levels of 17 organochlorine pesticides in snow. The parameters affecting the extraction efficiency, such as the type and volume of the extraction and dispersive solvents, extraction time, and salt content, were optimized. The optimized conditions yielded a good performance, with enrichment factors ranging from 271 to 474 and recoveries ranging from 71.4 to 114.5% and relative standard deviations between 1.6 and 14.8%. The detection limits, calculated as three times the signal-to-noise ratio, ranged from 0.02 to 0.11 μg/L. The validated method was used to successfully analyze 17 analytes in snow water samples, overcoming the drawbacks of some existing low-density solvent liquid microextraction methods, which require special devices, large volumes of organic solvents, or complicated operation procedures.

  6. Optimally Stopped Optimization

    NASA Astrophysics Data System (ADS)

    Vinci, Walter; Lidar, Daniel A.

    2016-11-01

    We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark simulated annealing on a class of maximum-2-satisfiability (MAX2SAT) problems. We also compare the performance of a D-Wave 2X quantum annealer to the Hamze-Freitas-Selby (HFS) solver, a specialized classical heuristic algorithm designed for low-tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N =1098 variables, the D-Wave device is 2 orders of magnitude faster than the HFS solver, and, modulo known caveats related to suboptimal annealing times, exhibits identical scaling with problem size.

  7. [Simultaneous determination of seven residual solvents in bovis calculus artifactus by headspace gas chromatography].

    PubMed

    Chi, Shuyao; Wu, Dike; Sun, Jinhong; Ye, Ruhan; Wang, Xiaoyan

    2014-05-01

    A headspace gas chromatography (HS-GC) method was developed for the simultaneous determination of seven residual solvents (petroleum ether (60-90 degrees C), acetone, ethyl acetate, methanol, methylene chloride, ethanol and butyl acetate) in bovis calculus artifactus. The DB-WAX capillary column and flame ionization detector (FID) were used for the separation and detection of the residual solvents, and the internal standard method was used for the quantification. The chromatographic conditions, such as equilibrium temperature and equilibrium time, were optimized. Under the optimized conditions, all of the seven residual solvents showed good linear relationships with good correlation coefficients (not less than 0.999 3) in the prescribed concentration range. At three spiked levels, the recoveries for the seven residual solvents were 94.7%-105.2% with the relative standard deviations (RSDs) less than 3.5%. The limits of detection (LODs) of the method were 0.43-5.23 mg/L, and the limits of quantification (LOQs) were 1.25-16.67 mg/L. The method is simple, rapid, sensitive and accurate, and is suitable for the simultaneous determination of the seven residual solvents in bovis calculus artifactus.

  8. Deep eutectic solvents for the purification of chloromycetin and thiamphenicol from milk.

    PubMed

    Li, Guizhen; Zhu, Tao; Row, Kyung Ho

    2017-02-01

    Deep eutectic solvents were used in both dispersive liquid-liquid microextraction and solid-phase extraction for the purification of chloromycetin and thiamphenicol from milk. In the dispersive liquid-liquid microextraction procedure, deep eutectic solvents mixed with chloroform at different ratios (0:1-5:1, v/v) were used as the extraction agent to optimize the procedure, and the ratio of 2:1 v/v was found to be the best extraction agent with 87.23 and 83.17% recoveries of chloromycetin and thiamphenicol, respectively. Furthermore, deep eutectic solvents were also used to modify molecular imprinted polymers in solid-phase extraction procedure, and the polymers were used to purify chloromycetin and thiamphenicol from milk. Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy were used to characterize the polymers. The solid-phase extraction recoveries with deep eutectic solvents with molecularly imprinted polymers (chloromycetin and thiamphenicol, two templates), molecularly imprinted polymers (without deep eutectic solvents), and nonimprinted polymers (without a template) for chloromycetin were 91.23, 82.64, and 57.3%, respectively, and recoveries for thiamphenicol were 87.02, 79.03, and 52.27%, respectively. The recoveries of chloromycetin and thiamphenicol from milk in the solid-phase extraction procedure were higher than using deep eutectic solvents mixed with chloroform as the extraction agent in the dispersive liquid-liquid microextraction procedure.

  9. How to design a good photoresist solvent package using solubility parameters and high-throughput research

    NASA Astrophysics Data System (ADS)

    Tate, Michael P.; Cutler, Charlotte; Sakillaris, Mike; Kaufman, Michael; Estelle, Thomas; Mohler, Carol; Tucker, Chris; Thackeray, Jim

    2014-03-01

    Understanding fundamental properties of photoresists and how interactions between photoresist components affect performance targets are crucial to the continued success of photoresists. More specifically, polymer solubility is critical to the overall performance capability of the photoresist formulation. While several theories describe polymer solvent solubility, the most common industrially applied method is Hansen's solubility parameters. Hansen's method, based on regular solution theory, describes a solute's ability to dissolve in a solvent or solvent blend using four physical properties determined experimentally through regression of solubility data in many known solvents. The four physical parameters are dispersion, polarity, hydrogen bonding, and radius of interaction. Using these parameters a relative cohesive energy difference (RED), which describes a polymer's likelihood to dissolve in a given solvent blend, may be calculated. Leveraging a high throughput workflow to prepare and analyze the thousands of samples necessary to calculate the Hansen's solubility parameters from many different methacrylate-based polymers, we compare the physical descriptors to reveal a large range of polarities and hydrogen bonding. Further, we find that Hansen's model correctly predicts the soluble/insoluble state of 3-component solvent blends where the dispersion, polar, hydrogen-bonding, and radius of interaction values were determined through regression of experimental values. These modeling capabilities have allowed for optimization of the photoresist solubility from initial blending through application providing valuable insights into the nature of photoresist.

  10. Biological monitoring of chlorinated hydrocarbon solvents

    SciTech Connect

    Monster, A.C.

    1986-08-01

    The possibility of biological monitoring of exposure to some volatile, halogenated hydrocarbons will be discussed. Most of these agents are widely used as solvents. All agents act on the nervous system as narcotics and differ widely in toxicity. Most of the solvents undergo biotransformation to metabolites. This allows biological assessment of exposure by measurement of the solvent and/or metabolites in exhaled air, blood, and/or urine. However, the same metabolites may occur with exposure to different chlorinated hydrocarbons, eg, trichloroethanol and trichloroacetic acid from exposure to trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane. On the other hand, these agents differ widely in the percentage that is metabolized. There are large gaps in our knowledge, however, and much research will have to be carried out before even tentative data can be established for most of the solvents.

  11. [Shoe factory workers, solvents and health].

    PubMed

    Foà, Vito; Martinotti, Irene

    2012-01-01

    Exposure to organic solvents in footwear manufacturing industry came from the glues used adhering the shoe parts to each other. Benzene was the first solvent used in shoe factories until the evidence of its capacity to cause leukaemia. Then, the demonstration that exposure to n-hexane was related to distal polyneuropathy limited the use of this substance. After that, results of neurotoxicological studies conducted on workers exposed to different mixtures of organic solvents make necessary prevention measure directed to a progressive reduction of air dispersion of these chemicals. Today exposure to solvents in workplaces is regulated by health based exposure limit values that should warranty absence of central nervous system effects. One of the most important rules of occupational medicine is verify that these exposure levels are really health protective also for workers with increased susceptibility.

  12. Deasphalted oil -- A natural asphaltene solvent

    SciTech Connect

    Jamaluddin, A.K.M.; Nazarko, T.W.; Sills, S.; Fuhr, B.J.

    1995-11-01

    Asphaltene deposition in the near-wellbore region can block pore throats, change wettability characteristics and relative-permeability relationships, and therefore, reduce oil production. Conventional aromatic solvents (e.g., toluene, xylene) alone or in combination with various dispersants are used to remove asphaltene damage from the near-wellbore region. However, these aromatic solvents are expensive and are not environmentally friendly. The objective of this work was to systematically evaluate the asphaltene-solvating power of various non conventional solvents, including deasphalted oil, using a light-scattering technique. Experimental results suggest that deasphalted oil is a strong asphaltene solvent presumably because of its native resin and aromatic contents. Addition of asphaltene dispersants also increases the solubilizing power of the deasphalted oil. Furthermore, various refinery and heavy oil upgrader streams show strong ability to solubilize asphaltenes.

  13. Deasphalted oil: A natural asphaltene solvent

    SciTech Connect

    Jamaluddin, A.K.M.; Nazarko, T.W.; Sills, S.; Fuhr, B.J.

    1996-08-01

    Asphaltene deposition in the near-wellbore region can block pore throats, change wettability characteristics and relative-permeability relationships, and therefore, reduce oil production. Conventional aromatic solvents (e.g., toluene and xylene) alone or in combination with various dispersants are used to remove asphaltene damage from the near-wellbore region. However, these aromatic solvents are expensive and are not environmentally friendly. The objective of this work was to systematically evaluate the asphaltene-solvating power of various nonconventional solvents, including deasphalted oil, using a light-scattering technique. Experimental results suggest that deasphalted oil is a strong asphaltene solvent presumably because of its native resin and aromatic contents. Addition of asphaltene dispersants also increases the solubilizing power of the deasphalted oil. Furthermore, various refinery and heavy oil upgrader streams show strong ability to solubilize asphaltenes.

  14. "Solvent Effects" in 1H NMR Spectroscopy.

    ERIC Educational Resources Information Center

    Cavaleiro, Jose A. S.

    1987-01-01

    Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

  15. Implicit solvent methods for free energy estimation

    PubMed Central

    Decherchi, Sergio; Masetti, Matteo; Vyalov, Ivan; Rocchia, Walter

    2014-01-01

    Solvation is a fundamental contribution in many biological processes and especially in molecular binding. Its estimation can be performed by means of several computational approaches. The aim of this review is to give an overview of existing theories and methods to estimate solvent effects giving a specific focus on the category of implicit solvent models and their use in Molecular Dynamics. In many of these models, the solvent is considered as a continuum homogenous medium, while the solute can be represented at the atomic detail and at different levels of theory. Despite their degree of approximation, implicit methods are still widely employed due to their trade-off between accuracy and efficiency. Their derivation is rooted in the statistical mechanics and integral equations disciplines, some of the related details being provided here. Finally, methods that combine implicit solvent models and molecular dynamics simulation, are briefly described. PMID:25193298

  16. United States Air Force Wipe Solvent Testing

    NASA Technical Reports Server (NTRS)

    Hornung, Steven D.; Beeson, Harold D.

    2000-01-01

    The Wright-Patterson Air Force Base (WPAFB), as part of the Air Force Material Command, requested that NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) conduct testing and analyses in support of the United States Air Force Wipe Solvent Development Project. The purpose of the wipe solvent project is to develop an alternative to be used by Air Force flight line and maintenance personnel for the wipe cleaning of oxygen equipment. This report provides material compatibility, liquid oxygen (LOX) mechanical impact, autogenous ignition temperature (AIT), and gauge cleaning test data for some of the currently available solvents that may be used to replace CFC-113 and methyl chloroform. It provides data from previous WSTF test programs sponsored by the Naval Sea Systems Command, the Kennedy Space Center, and other NASA programs for the purpose of assisting WP AFB in identifying the best alternative solvents for validation testing.

  17. Used lubricating oil recycling using hydrocarbon solvents.

    PubMed

    Hamad, Ahmad; Al-Zubaidy, Essam; Fayed, Muhammad E

    2005-01-01

    A solvent extraction process using new hydrocarbon solvents was employed to treat used lubricant oil. The solvents used were liquefied petroleum gas (LPG) condensate and stabilized condensate. A demulsifier was used to enhance the treatment process. The extraction process using stabilized condensate demonstrated characteristics that make it competitive with existing used oil treatment technologies. The process is able to reduce the asphaltene content of the treated lubricating oil to 0.106% (w/w), the ash content to 0.108%, and the carbon residue to 0.315% with very low levels of contaminant metals. The overall yield of oil is 79%. The treated used oil can be recycled as base lubricating oil. The major disadvantage of this work is the high temperature of solvent recovery. Experimental work and results are presented in detail.

  18. Innovative Technologies for Chlorinated Solvent Remediation

    NASA Astrophysics Data System (ADS)

    Pennell, Kurt D.; Cápiro, Natalie L.

    2014-07-01

    The following sections are included: * INTRODUCTION * TRADITIONAL REMEDIATION TECHNOLOGIES (1980s) * RESEARCH AND DEVELOPMENT OF INNOVATIVE REMEDIATION TECHNOLOGIES (1990s-2000s) * CURRENT TRENDS IN CHLORINATED SOLVENT REMEDIATION (2010s) * CLOSING THOUGHTS * REFERENCES

  19. Wetting of polymers by their solvents.

    PubMed

    Lequeux, François; Talini, Laurence; Verneuil, Emilie; Delannoy, Guillaume; Valois, Pauline

    2016-02-01

    We review the studies on the wetting of soluble polymeric substrates by their solvents, both in the literature and conducted in our group in the past decade. When a droplet of solvent spreads on a soluble polymer layer, its wetting angle can strongly vary with the contact line velocity even at capillary numbers smaller than unity, in contrast to non-soluble substrates. The solvent content in the polymer is a key parameter for the spreading dynamics; that content is set by the initial conditions, but also by the transfers occurring from the droplet to the polymer layer during spreading. We focus on hydrophilic amorphous polymers that are glassy at room temperature, and we discuss the consequences on wetting of the very large changes in the polymer physical properties induced by solvent sorption. We finally present new results on polymers of varying molar masses, and show how they open new perspectives for a better understanding of powder dissolution.

  20. Optimization and determination of polycyclic aromatic hydrocarbons in biochar-based fertilizers.

    PubMed

    Chen, Ping; Zhou, Hui; Gan, Jay; Sun, Mingxing; Shang, Guofeng; Liu, Liang; Shen, Guoqing

    2015-03-01

    The agronomic benefit of biochar has attracted widespread attention to biochar-based fertilizers. However, the inevitable presence of polycyclic aromatic hydrocarbons in biochar is a matter of concern because of the health and ecological risks of these compounds. The strong adsorption of polycyclic aromatic hydrocarbons to biochar complicates their analysis and extraction from biochar-based fertilizers. In this study, we optimized and validated a method for determining the 16 priority polycyclic aromatic hydrocarbons in biochar-based fertilizers. Results showed that accelerated solvent extraction exhibited high extraction efficiency. Based on a Box-Behnken design with a triplicate central point, accelerated solvent extraction was used under the following optimal operational conditions: extraction temperature of 78°C, extraction time of 17 min, and two static cycles. The optimized method was validated by assessing the linearity of analysis, limit of detection, limit of quantification, recovery, and application to real samples. The results showed that the 16 polycyclic aromatic hydrocarbons exhibited good linearity, with a correlation coefficient of 0.996. The limits of detection varied between 0.001 (phenanthrene) and 0.021 mg/g (benzo[ghi]perylene), and the limits of quantification varied between 0.004 (phenanthrene) and 0.069 mg/g (benzo[ghi]perylene). The relative recoveries of the 16 polycyclic aromatic hydrocarbons were 70.26-102.99%.

  1. Absorption Heat Pump Cycles

    NASA Astrophysics Data System (ADS)

    Kunugi, Yoshifumi; Kashiwagi, Takao

    Various advanced absorption cycles are studied, developed and invented. In this paper, their cycles are classified and arranged using the three categories: effect, stage and loop, then an outline of the cycles are explained on the Duehring diagram. Their cycles include high COP cycles for refrigerations and heat pumps, high temperature lift cycles for heat transformer, absorption-compression hybrid cycles and heat pump transformer cycle. The highest COPi is attained by the seven effect cycle. In addition, the cycles for low temperature are invented and explained. Furthermore the power generation • refrigeration cycles are illustrated.

  2. Effect of the solvent type and temperature on phytosterol contents and compositions of wheat straw, bran, and germ extracts.

    PubMed

    Dunford, Nurhan Turgut; Irmak, Sibel; Jonnala, Ramakanth

    2009-11-25

    Wheat fractions, such as bran, germ, and straw, are rich in a number of health beneficial bioactive compounds. However, they have not been exploited to their full capacity for value-added product development. This study examines the potential of recovering phytosterol (PS)-enriched extracts from wheat germ, bran, and straw. The main objective of the study was to evaluate the effect of solvent type and temperature on PS content and composition in straw, bran, and germ extracts. Petroleum ether, chloroform, n-hexane, and ethanol were used as solvents. A pressurized solvent extraction system was used for extraction of wheat fractions. Germ extracts had the highest total PS content followed by straw and bran extracts. Beta-sitosterol, campesterol, and stigmasterol were the main PSs in all of the extracts. Ethanol extraction resulted in the lowest total PS recovery from germ. Solvent type had a significant effect on PS composition in straw extracts. beta-Sitosterol was the most abundant PS in straw hexane extracts (74% of total PS). Petroleum ether, chloroform, and ethanol extracted more stigmasterol than beta-sitosterol from straw. This study demonstrated that the solvent type and temperature had significant effects on both PS content and composition of extracts collected from wheat fractions. Because of the complex nature of the agricultural materials, solvent selection and process optimization need to be based on experimental data. Pressurized solvent extraction is a useful technique to screen complex biological materials for their composition and to determine processing conditions to be optimized.

  3. A Binary-Like Approach for the Computer Assisted Method Development of Isocratic and Programmed Ternary Solvent Elutions in Reversed-Phase Liquid Chromatography

    PubMed Central

    García-Lavandeira, J.; Martinez-Pontevedra, J.A.; Cela, R.

    2012-01-01

    A specific tool to enable exploration of multisolvent isocratic and programmed elutions for the computer assisted method development of reversed-phase liquid chromatography separations is described. The tool is purposely identical to those used in the optimization of binary solvent systems, which are by far the most commonly used by chromatographers. Existing data from failed binary solvent optimization processes are reused to explore ternary solvent systems with a few additional isocratic and programmed runs. This allows the development of efficient retention models for ternary systems, although the work of the chromatographer remains identical to that for optimization of binary systems. The retention models are used to develop an unattended optimization process and finally, the chromatographer selects the most satisfactory solution for testing and implementing in routine analysis. The process is exemplified with a mixture of 12 compounds that cannot be separated satisfactorily in aqueous binary solvent systems with methanol and acetonitrile as modifiers. PMID:22291054

  4. Method of stripping metals from organic solvents

    DOEpatents

    Todd, Terry A.; Law, Jack D.; Herbst, R. Scott; Romanovskiy, Valeriy N.; Smirnov, Igor V.; Babain, Vasily A.; Esimantovski, Vyatcheslav M.

    2009-02-24

    A new method to strip metals from organic solvents in a manner that allows for the recycle of the stripping agent. The method utilizes carbonate solutions of organic amines with complexants, in low concentrations, to strip metals from organic solvents. The method allows for the distillation and reuse of organic amines. The concentrated metal/complexant fraction from distillation is more amenable to immobilization than solutions resulting from current practice.

  5. Recovery, Reuse, and Recycle of Solvents.

    DTIC Science & Technology

    1985-12-01

    So. San Francisco, CA 94080 (513) 771-2300 (415) 589-9600 Buflovak Division Safety-Kleen Corp. Blaw - Knox food and Chimical Eq. Co. 655 Big Timber Rd...ing, oil and grease removal for cleanup, protective surface removal, and cleaning of wheel bearings. Both hydrocarbon solvents and halogenated solvents...fluid but it could still be blended and downgraded for use as a metal cleaner, - such as using it to clean wheel bearings. Heptane is also an excellent

  6. Hydrogen recovery by novel solvent systems

    SciTech Connect

    Shinnar, R.; Ludmer, Z.; Ullmann, A.

    1991-08-01

    The objective of this work is to develop a novel method for purification of hydrogen from coal-derived synthesis gas. The study involved a search for suitable mixtures of solvents for their ability to separate hydrogen from the coal derived gas stream in significant concentration near their critical point of miscibility. The properties of solvent pairs identified were investigated in more detail to provide data necessary for economic evaluation and process development.

  7. Water as a Solvent for Life

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; Pratt, Lawrence R.

    2015-01-01

    "Follow the water" is our basic strategy in searching for life in the universe. The universality of water as the solvent for living systems is usually justified by arguing that water supports the rich organic chemistry that seeds life, but alternative chemistries are possible in other organic solvents. Here, other, essential criteria for life that have not been sufficiently considered so far, will be discussed.

  8. Competitive solvent-molecule interactions govern primary processes of diphenylcarbene in solvent mixtures

    PubMed Central

    Knorr, Johannes; Sokkar, Pandian; Schott, Sebastian; Costa, Paolo; Thiel, Walter; Sander, Wolfram; Sanchez-Garcia, Elsa; Nuernberger, Patrick

    2016-01-01

    Photochemical reactions in solution often proceed via competing reaction pathways comprising intermediates that capture a solvent molecule. A disclosure of the underlying reaction mechanisms is challenging due to the rapid nature of these processes and the intricate identification of how many solvent molecules are involved. Here combining broadband femtosecond transient absorption and quantum mechanics/molecular mechanics simulations, we show for one of the most reactive species, diphenylcarbene, that the decision-maker is not the nearest solvent molecule but its neighbour. The hydrogen bonding dynamics determine which reaction channels are accessible in binary solvent mixtures at room temperature. In-depth analysis of the amount of nascent intermediates corroborates the importance of a hydrogen-bonded complex with a protic solvent molecule, in striking analogy to complexes found at cryogenic temperatures. Our results show that adjacent solvent molecules take the role of key abettors rather than bystanders for the fate of the reactive intermediate. PMID:27708264

  9. Microencapsulation of advanced solvents for carbon capture.

    PubMed

    Stolaroff, Joshuah K; Ye, Congwang; Oakdale, James S; Baker, Sarah E; Smith, William L; Nguyen, Du T; Spadaccini, Christopher M; Aines, Roger D

    2016-10-20

    Purpose-designed, water-lean solvents have been developed to improve the energy efficiency of CO2 capture from power plants, including CO2-binding organic liquids (CO2BOLs) and ionic liquids (ILs). Many of these solvents are highly viscous or change phases, posing challenges for conventional process equipment. Such problems can be overcome by encapsulation. Micro-Encapsulated CO2 Sorbents (MECS) consist of a CO2-absorbing solvent or slurry encased in spherical, CO2-permeable polymer shells. The resulting capsules have diameters in the range of 100-600 μm, greatly increasing the surface area and CO2 absorption rate of the encapsulated solvent. Encapsulating these new solvents requires careful selection of shell materials and fabrication techniques. We find several common classes of polymers are not compatible with MECS production, but we develop two custom formulations, a silicone and an acrylate, that show promise for encapsulating water-lean solvents. We make the first demonstration of an encapsulated IL for CO2 capture. The rate of CO2 absorption is enhanced by a factor of 3.5 compared to a liquid film, a value that can be improved by further development of shell materials and fabrication techniques.

  10. Solvent dependent photophysical properties of dimethoxy curcumin

    NASA Astrophysics Data System (ADS)

    Barik, Atanu; Indira Priyadarsini, K.

    2013-03-01

    Dimethoxy curcumin (DMC) is a methylated derivative of curcumin. In order to know the effect of ring substitution on photophysical properties of curcumin, steady state absorption and fluorescence spectra of DMC were recorded in organic solvents with different polarity and compared with those of curcumin. The absorption and fluorescence spectra of DMC, like curcumin, are strongly dependent on solvent polarity and the maxima of DMC showed red shift with increase in solvent polarity function (Δf), but the above effect is prominently observed in case of fluorescence maxima. From the dependence of Stokes' shift on solvent polarity function the difference between the excited state and ground state dipole moment was estimated as 4.9 D. Fluorescence quantum yield (ϕf) and fluorescence lifetime (τf) of DMC were also measured in different solvents at room temperature. The results indicated that with increasing solvent polarity, ϕf increased linearly, which has been accounted for the decrease in non-radiative rate by intersystem crossing (ISC) processes.

  11. Optimization of the ultrasound-assisted extraction of anthocyanins and total phenolic compounds in mulberry (Morus nigra) pulp.

    PubMed

    Espada-Bellido, Estrella; Ferreiro-González, Marta; Carrera, Ceferino; Palma, Miguel; Barroso, Carmelo G; Barbero, Gerardo F

    2017-03-15

    New ultrasound-assisted extraction methods for the determination of anthocyanins and total phenolic compounds present in mulberries have been developed. Several extraction variables, including methanol composition (50-100%), temperature (10-70°C), ultrasound amplitude (30-70%), cycle (0.2-0.7s), solvent pH (3-7) and solvent-solid ratio (10:1.5-20:1.5) were optimized. A Box-Behnken design in conjunction with a response surface methodology was employed to optimize the conditions for the maximum response based on 54 different experiments. Two response variables were considered: total anthocyanins and total phenolic compounds. Extraction temperature and solvent composition were found to be the most influential parameters for anthocyanins (48°C and 76%) and phenolic compounds (64°C and 61%). The developed methods showed high reproducibility and repeatability (RSD<5%). Finally, the new methods were successfully applied to real samples in order to investigate the presence of anthocyanins and total phenolic compounds in several mulberry jams.

  12. Solvent-bar microextraction--using a silica monolith as the extractant phase holder.

    PubMed

    Xu, Li; Lee, Hian Kee

    2009-07-17

    In this paper, a novel liquid-phase microextraction (LPME) approach, based on solvent-bar microextraction (SBME), was developed in which a silica monolith was used as the extractant solvent holder. Owing to the porous nature of the monolith, the extractant solvent could be easily held in the material; when the monolith containing the extractant solvent was exposed to the sample solution, analytes could directly diffuse from the sample solution into the extractant solvent. Polycyclic aromatic hydrocarbons (PAHs) were used as model analytes to evaluate the procedure. Through the investigation of the effect of agitation speed, extraction time, length of the monolith (that determined the volume of organic extractant solvent) and salt concentration on extraction efficiency, the following optimal extraction conditions were obtained: stirring at 1000 rpm for 30 min without salt addition using a 4-mm silica monolith. The limits of detection ranged from 3.9 pg/mL to 28.8 pg/mL, with relative standard deviations of between 8.16% and 10.5% on the same silica monolith. The linearity was 0.05-200 ng/mL for fluoranthene and pyrene, and 0.5-200 ng/mL for chrysene and benzo[b]fluoranthene, with acceptable correlation coefficient. When this method was applied for the spiked real river sample, the relative recoveries ranged from 87.1% to 100.7% for the tested PAHs. This method was also compared to polymeric hollow fiber-based SBME and hollow fiber-protected LPME and found to provide better results. Additionally, compared with the polymeric hollow fiber, the silica monolith possesses good resistance to extreme conditions, such as high temperature and pH, and is more compatible with various organic solvents. This is the first report of an application of a monolithic material for LPME, and as a solvent holder for SBME. It extends the scope of applications of such materials, to analytical chemistry, specifically to sample preparation.

  13. Solvent, temperature and concentration effects on the optical rotatory dispersion of (R)-3-methylcyclohexanone

    NASA Astrophysics Data System (ADS)

    Alenaizan, Asem; Al-Basheer, Watheq; Musa, Musa M.

    2017-02-01

    Optical rotatory dispersion (ORD) spectra are reported for isolated and solvated (R)-3-methylcyclohexanone (R-3MCH) in 10 solvents, of wide polarity range, and over the spectral range 350-650 nm. Sample concentration effects on ORD spectra of R-3MCH were also recorded and investigated over widely varying concentrations from 2.5 × 10-3 to 2.5 × 10-1 g/mL where an observed sensitivity of optical rotation (OR) to incident light wavelength at low concentrations is correlated to solvent effects. Temperature effects were also studied by recording ORD spectra over the temperature range 0-65 °C in toluene. Recorded specific OR was plotted against various solvent parameters, namely, dipole moment, polarity, refractive index and polarizability to probe solvent effects. Furthermore, solvent effects were studied by incorporating Kamlet's and Taft's solvent parameters in the multi-parametric linear fitting. Theoretically, ORD spectra and populations of optimized geometries of equatorial and axial conformers of R-3MCH were calculated in the gas and solvated phases. All theoretical calculations were performed employing the polarizable continuum model using density functional theoretical and composite scheme (G4) methods with aug-cc-pVTZ and aug-cc-pVDZ basis sets. Net ORD spectra of R-3MCH were generated by the Boltzmann-weighted sum of the contributions of the dominant conformers. Upon comparing theoretical and experimental ORD spectra, a very good agreement is observed for the ORD spectra in the gas phase and high polarity solvents compared to relatively lesser agreement in low polarity solvents.

  14. EXponentially Converging Eradication Pulse Train (EXCEPT) for solvent-signal suppression in investigations with variable T1 times

    NASA Astrophysics Data System (ADS)

    Satterfield, Emmalou T.; Pfaff, Annalise R.; Zhang, Wenjia; Chi, Lingyu; Gerald, Rex E.; Woelk, Klaus

    2016-07-01

    Selective presaturation is a common technique for suppressing excessive solvent signals during proton NMR analysis of dilute samples in protic solvents. When the solvent T1 relaxation time constant varies within a series of samples, parameters for the presaturation sequence must often be re-adjusted for each sample. The EXCEPT (EXponentially Converging Eradication Pulse Train) presaturation pulse sequence was developed to eliminate time consuming pulse-parameter re-optimization as long as the variation in the solvent's T1 remains within an order of magnitude. EXCEPT consists of frequency-selective inversion pulses with progressively decreasing interpulse delays. The interpulse delays were optimized to encompass T1 relaxation times ranging from 1 to 10 s, but they can be easily adjusted by a single factor for other ranges that fall within an order of magnitude with respect to T1. Sequences with different numbers of inversion pulses were tested to maximize suppression while minimizing the number of pulses and thus the total time needed for suppression. The EXCEPT-16 experiment, where 16 denotes the number of inversion pulses, was found satisfactory for many standard applications. Experimental results demonstrate that EXCEPT provides effective T1-insensitive solvent suppression as predicted by the theory. The robustness of EXCEPT with respect to changes in solvent T1 allows NMR investigations to be carried out for a series of samples without the need for pulse-parameter re-optimization for each sample.

  15. Preparation of graphene sponge by vapor phase reduction for oil and organic solvent removal

    NASA Astrophysics Data System (ADS)

    Wu, Ruihan; Yu, Baowei; Jin, Xinyan; Liu, Xiaoyang; Bai, Yitong; Chen, Lingyun; Ming, Zhu; Yang, Hua; Yang, Sheng-Tao; Luo, Jianbin

    2016-10-01

    Due to the porous structure and hydrophobicity, graphene sponge has huge adsorption capacity for oils and organic solvents. In this study, we reported that graphene sponge could be prepared by vapor phase reduction (denoted as VPRGS) for oil and organic solvent removal. Graphene oxide was lyophilized and reduced by steamy hydrazine hydrate to produce VPRGS. VPRGS had huge capacity for oils and organic solvents (72-224 g g-1). In particular, the adsorption capacity for crude oil reached 165 g g-1, suggesting that VPRGS could be applied in oil leakage remediation. VPRGS could treat pollutants both in pure liquid form and in the simulated sea water, where the hydrophobic nature of VPRGS allowed the floating of VPRGS on simulated sea water. VPRGS could be easily regenerated without obvious capacity loss up to 9 cycles. The implications to the applications of VPRGS in oil/water separation and water remediation are discussed.

  16. Hydrological cycle.

    PubMed

    Gonçalves, H C; Mercante, M A; Santos, E T

    2011-04-01

    The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water.

  17. CHEMICAL STABILITY OF POLYPHENYLENE SULFIDE IN THE NEXT GENERATION SOLVENT FOR CAUSTIC-SIDE SOLVENT EXTRACTION

    SciTech Connect

    Fondeur, F.; Fink, S.

    2011-12-08

    The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. For simplicity, this solvent is referred to as the Next Generation Solvent (NGS). The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The initial deployment target envisioned for the technology was within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with polyphenylene sulfide (PPS), the polymer used in the coalescers within MCU. This report provides the data from exposing PPS polymer to NGS. The test was conducted over a three month period. PPS is remarkably stable in the presence of the next generation solvent. Testing showed no indication of swelling or significant leaching. Preferential sorption of the Modifier on PPS was observed but the same behavior occurs with the baseline solvent. Therefore, PPS coalescers exposed to the NGS are expected to perform comparably to those in contact with the baseline solvent.

  18. Effect of Organic Solvents on the Yield of Solvent-Tolerant Pseudomonas putida S12

    PubMed Central

    Isken, Sonja; Derks, Antoine; Wolffs, Petra F. G.; de Bont, Jan A. M.

    1999-01-01

    Solvent-tolerant microorganisms are useful in biotransformations with whole cells in two-phase solvent-water systems. The results presented here describe the effects that organic solvents have on the growth of these organisms. The maximal growth rate of Pseudomonas putida S12, 0.8 h−1, was not affected by toluene in batch cultures, but in chemostat cultures the solvent decreased the maximal growth rate by nearly 50%. Toluene, ethylbenzene, propylbenzene, xylene, hexane, and cyclohexane reduced the biomass yield, and this effect depended on the concentration of the solvent in the bacterial membrane and not on its chemical structure. The dose response to solvents in terms of yield was linear up to an approximately 200 mM concentration of solvent in the bacterial membrane, both in the wild type and in a mutant lacking an active efflux system for toluene. Above this critical concentration the yield of the wild type remained constant at 0.2 g of protein/g of glucose with increasing concentrations of toluene. The reduction of the yield in the presence of solvents is due to a maintenance higher by a factor of three or four as well as to a decrease of the maximum growth yield by 33%. Therefore, energy-consuming adaptation processes as well as the uncoupling effect of the solvents reduce the yield of the tolerant cells. PMID:10347053

  19. Influence of solute-solvent coordination on the orientational relaxation of ion assemblies in polar solvents.

    PubMed

    Ji, Minbiao; Hartsock, Robert W; Sung, Zheng; Gaffney, Kelly J

    2012-01-07

    We have investigated the rotational dynamics of lithium thiocyanate (LiNCS) dissolved in various polar solvents with time and polarization resolved vibrational spectroscopy. LiNCS forms multiple distinct ionic structures in solution that can be distinguished with the CN stretch vibrational frequency of the different ionic assemblies. By varying the solvent and the LiNCS concentration, the number and type of ionic structures present in solution can be controlled. Control of the ionic structure provides control over the volume, shape, and dipole moment of the solute, critical parameters for hydrodynamic and dielectric continuum models of friction. The use of solutes with sizes comparable to or smaller than the solvent molecules also helps amplify the sensitivity of the measurement to the short-ranged solute-solvent interaction. The measured orientational relaxation dynamics show many clear and distinct deviations from simple hydrodynamic behavior. All ionic structures in all solvents exhibit multi-exponential relaxation dynamics that do not scale with the solute volume. For Lewis base solvents such as benzonitrile, dimethyl carbonate, and ethyl acetate, the observed dynamics strongly show the effect of solute-solvent complex formation. For the weak Lewis base solvent nitromethane, we see no evidence for solute-solvent complex formation, but still see strong deviation from the predictions of simple hydrodynamic theory.

  20. Application of a statistically enhanced, novel, organic solvent stable lipase from Bacillus safensis DVL-43.

    PubMed

    Kumar, Davender; Parshad, Rajinder; Gupta, Vijay Kumar

    2014-05-01

    This paper presents the molecular identification of a newly isolated bacterial strain producing a novel and organic solvent stable lipase, statistical optimization of fermentation medium, and its application in the synthesis of ethyl laurate. On the basis of nucleotide homology and phylogenetic analysis of 16S rDNA sequence, the strain was identified as Bacillus safensis DVL-43 (Gen-bank accession number KC156603). Optimization of fermentation medium using Plackett-Burman design and response surface methodology led to 11.4-fold increase in lipase production. The lipase from B. safensis DVL-43 exhibited excellent stability in various organic solvents. The enzyme retained 100% activity after 24h incubation in xylene, DMSO and toluene, each solvent being used at a concentration of 25% (v/v). The use of partially purified DVL-43 lipase as catalyst in the synthesis of ethyl laurate, an esterification product of lauric acid and ethanol, resulted in 80% esterification in 12h under optimized conditions. The formation of ethyl laurate was confirmed using TLC and (1)H NMR. Organic solvent stable lipases exhibiting potential application in enzymatic esterification are in great demand in flavor, fine chemicals and pharma industries. We could not find any report on lipase production from B. safensis strain and its application in esterification.

  1. Stability of the Caustic-Side Solvent Extraction (CSSX) Process Solvent: Effect of High Nitrite on Solvent Nitration

    SciTech Connect

    Bonnesen, P.V.

    2002-06-26

    The purpose of this investigation was to determine whether nitrated organic compounds could be formed during operation of the Caustic-Side Solvent Extraction (CSSX) process, and whether such compounds would present a safety concern. The CSSX process was developed to remove cesium from alkaline high-level salt waste stored at the US Department of Energy Savannah River Site (SRS). The solvent is composed of the cesium extractant calix[4]arene-bis-(4-tert-octylbenzo-crown-6) (BOBCalixC6), a fluorinated alcohol phase modifier, tri-n-octylamine (TOA), and an isoparaffinic diluent (Iospar{reg_sign}). During the CSSX process, the solvent is expected to be exposed to high concentrations of nitrate and nitrite dissolved in the alkaline waste feed. The solvent will also be exposed to dilute (50 mM) nitric acid solutions containing low concentrations of nitrite during scrubbing, followed by stripping with 1 mM nitric acid. The solvent is expected to last for one year of plant operation, and the temperatures the solvent may experience during the process could range from as low as 15 C to as high as 35 C. Excursions from standard process conditions could result in the solvent experiencing higher temperatures, as well as concentrations of nitrate, nitrite, and most importantly nitric acid, that exceed normal operating conditions. Accordingly, conditions may exist where nitration reactions involving the solvent components, possibly leading to other chemical reactions stemming from nitration reactions, could occur. To model such nitration reactions, the solvent was exposed to the types of nitrate- and nitrite-containing solutions that might be expected to be encountered during the process (even under off-normal conditions), as a function of time, temperature, and concentration of nitrate, nitrite, and nitric acid. The experiments conducted as part of this report were designed to examine the more specific effect that high nitrite concentrations could have on forming nitrated

  2. Optimal synthesis of a pressure swing adsorption process for CO2 capture

    SciTech Connect

    Agarwal, A.; Biegler, L.; Zitney, S.

    2008-01-01

    The emission of carbon dioxide from cement industry and power plants that burn fossil fuels is the major cause for the accumulation of CO2 in the atmosphere, which causes long-range environmental problems. One option to mitigate the emission of CO2 is to capture it from the emission sources and store it to the ocean or depleted oil field or use it for enhanced oil recovery. CO2 recovery has been achieved by gas absorption employing solutions of carbonates and alkanolamines. However, this process is energy-intensive for the regeneration of solvent and also faces problems due to corrosion. Recently, the pressure swing adsorption (PSA) process has been considered as an alternative to the absorption process. PSA processes have been widely applied for the removal of CO2 from various feed mixtures, such as CO2 in the steam reformer off gas, landfill gas and natural gas. In all these commercial PSA cycles, the weakly adsorbed component in the mixture is the desired product and enriching the strongly adsorbed CO2 is not a concern. On the other hand, for the capture of CO2 for sequestration, it is necessary to concentrate the CO2 to a high purity to reduce the compression and transportation cost. Thus, it is necessary to develop a PSA cycle by which a high-purity product for the strongly adsorbed component with a high recovery is obtained. A multitude of PSA cycles and adsorbents have been developed for producing highly pure heavy component (CO2) from feedstock with low CO2 concentration. Kikkinides et al. suggested a 4-bed 4-step process with activated carbon as the sorbent and could recover 68% of CO2 at 99.997% purity. Chue et al. compared activated carbon and zeolite 13X on a 3-bed 7-step process and concluded that the latter is better than the former for CO2 recovery. However, the CO2 recovery was low in their process due to the lack of a countercurrent step in the chosen cycle. Choi et al. reported more than 70% CO2 recovery at more than 90% purity for a modified 3

  3. Modeling of solvent flow effects in enzyme catalysis under physiological conditions

    NASA Astrophysics Data System (ADS)

    Schofield, Jeremy; Inder, Paul; Kapral, Raymond

    2012-05-01

    A stochastic model for the dynamics of enzymatic catalysis in explicit, effective solvents under physiological conditions is presented. Analytically-computed first passage time densities of a diffusing particle in a spherical shell with absorbing boundaries are combined with densities obtained from explicit simulation to obtain the overall probability density for the total reaction cycle time of the enzymatic system. The method is used to investigate the catalytic transfer of a phosphoryl group in a phosphoglycerate kinase-ADP-bis phosphoglycerate system, one of the steps of glycolysis. The direct simulation of the enzyme-substrate binding and reaction is carried out using an elastic network model for the protein, and the solvent motions are described by multiparticle collision dynamics which incorporates hydrodynamic flow effects. Systems where solvent-enzyme coupling occurs through explicit intermolecular interactions, as well as systems where this coupling is taken into account by including the protein and substrate in the multiparticle collision step, are investigated and compared with simulations where hydrodynamic coupling is absent. It is demonstrated that the flow of solvent particles around the enzyme facilitates the large-scale hinge motion of the enzyme with bound substrates, and has a significant impact on the shape of the probability densities and average time scales of substrate binding for substrates near the enzyme, the closure of the enzyme after binding, and the overall time of completion of the cycle.

  4. Dominant Decomposition Pathways for Ethereal Solvents in Li-O2 Batteries.

    PubMed

    García, Jeannette M; Horn, Hans W; Rice, Julia E

    2015-05-21

    The promise of high specific energies for Li-O2 batteries has driven research toward the development of new compatible materials for this emerging technology. Obtained energies, however, fall short of the theoretical values partly due to parasitic chemistries arising from organic solvent decomposition during battery cycling. Electrolyte solvent and salt decomposition have also been identified as limiting factors for rechargeability of the battery. Although lithium trifluorosulfonamide (LiTFSI) dissolved in 1,2-dimethoxyethane (DME) has been shown to be a promising solvent/electrolyte candidate for Li-O2 batteries, significant challenges remain, namely minimizing decomposition of both the solvent and electrolyte salt during battery cycling. Herein, we provide spectroscopic labeling studies to identify the source of H2 at high potentials during charge and propose a decomposition pathway for DME to lithium formate and acetate products at low potentials. NMR studies were preformed to show that DME decomposes to lithium formate and acetate in aqueous Li2O2, products which are also observed after D2O workups on cathodes after discharge. Finally, we use density functional theory (DFT) to elucidate a mechanistic pathway for DME decomposition that is based on known organic oxidation processes.

  5. Production of Thermostable Organic Solvent Tolerant Keratinolytic Protease from Thermoactinomyces sp. RM4: IAA Production and Plant Growth Promotion

    PubMed Central

    Verma, Amit; Singh, Hukum; Anwar, Mohammad S.; Kumar, Shailendra; Ansari, Mohammad W.; Agrawal, Sanjeev

    2016-01-01

    There are several reports about the optimization of protease production, but only few have optimized the production of organic solvent tolerant keratinolytic proteases that show remarkable exploitation in the development of the non-polluting processes in biotechnological industries. The present study was carried with aim to optimize the production of a thermostable organic solvent tolerant keratinolytic protease Thermoactinomyces sp. RM4 utilizing chicken feathers. Thermoactinomyces sp. RM4 isolated from the soil sample collected from a rice mill wasteyard site near Kashipur, Uttrakhand was identified on the basis of 16S rDNA analysis. The production of organic solvent tolerant keratinolytic protease enzyme by Thermoactinomyces sp. RM4 was optimized by varying physical culture conditions such as pH (10.0), temperature (60°C), inoculum percentage (2%), feather concentration (2%) and agitation rate (2 g) for feather degradation. The result showed that Thermoactinomyces sp. RM4 potentially produces extra-cellular thermostable organic solvent tolerant keratinolytic protease in the culture medium. Further, the feather hydrolysate from keratinase production media showed plant growth promoting activity by producing indole-3-acetic acid itself. The present findings suggest that keratinolytic protease from Thermoactinomyces sp. RM4 offers enormous industrial applications due to its organic solvent tolerant property in peptide synthesis, practical role in feather degradation and potential function in plant growth promoting activity, which might be a superior candidate to keep ecosystem healthy and functional. PMID:27555836

  6. Production of Thermostable Organic Solvent Tolerant Keratinolytic Protease from Thermoactinomyces sp. RM4: IAA Production and Plant Growth Promotion.

    PubMed

    Verma, Amit; Singh, Hukum; Anwar, Mohammad S; Kumar, Shailendra; Ansari, Mohammad W; Agrawal, Sanjeev

    2016-01-01

    There are several reports about the optimization of protease production, but only few have optimized the production of organic solvent tolerant keratinolytic proteases that show remarkable exploitation in the development of the non-polluting processes in biotechnological industries. The present study was carried with aim to optimize the production of a thermostable organic solvent tolerant keratinolytic protease Thermoactinomyces sp. RM4 utilizing chicken feathers. Thermoactinomyces sp. RM4 isolated from the soil sample collected from a rice mill wasteyard site near Kashipur, Uttrakhand was identified on the basis of 16S rDNA analysis. The production of organic solvent tolerant keratinolytic protease enzyme by Thermoactinomyces sp. RM4 was optimized by varying physical culture conditions such as pH (10.0), temperature (60°C), inoculum percentage (2%), feather concentration (2%) and agitation rate (2 g) for feather degradation. The result showed that Thermoactinomyces sp. RM4 potentially produces extra-cellular thermostable organic solvent tolerant keratinolytic protease in the culture medium. Further, the feather hydrolysate from keratinase production media showed plant growth promoting activity by producing indole-3-acetic acid itself. The present findings suggest that keratinolytic protease from Thermoactinomyces sp. RM4 offers enormous industrial applications due to its organic solvent tolerant property in peptide synthesis, practical role in feather degradation and potential function in plant growth promoting activity, which might be a superior candidate to keep ecosystem healthy and functional.

  7. Scale-up of recovery process for waste solvents

    SciTech Connect

    Bohnert, G.W.; Carey, D.A.

    1991-02-01

    Recycling of spent cleaning solvents, 1,1,1 trichloroethane, trichloroethylene, and trichlorotrifluoroethane at KCP was evaluated. Gas chromatography was used to identify stabilization levels in virgin and recycled solvent. Segregation, pretreatment and distillation processes were defined. Existing distillation equipment was modified and a solvent drying process was added. Recycled solvent quality of several production lots is also presented. 3 figs., 4 tabs.

  8. Solvent disperser for removing oil from sponge core

    SciTech Connect

    Di Foggio, R.

    1988-09-20

    This patent describes method for dispersing solvent for use in determining the oil saturation of an earth formation by means of sponge coring, comprising: (a) receiving solvent dripping downwardly, and (b) conducting the received solvent by means of capillary action to an application zone located and dimensioned for passing such solvent to the sponge in a sponge core barrel.

  9. Unsaturated phosphazenes as co-solvents for lithium-ion battery electrolytes

    NASA Astrophysics Data System (ADS)

    Harrup, Mason K.; Rollins, Harry W.; Jamison, David K.; Dufek, Eric J.; Gering, Kevin L.; Luther, Thomas A.

    2015-03-01

    This paper covers the synthesis and use of a related family of cyclic phosphazene solvents containing terminal unsaturations that are being considered as electrolyte additives in lithium-ion cells. A brief synopsis on the synthesis and purification of these compounds is given. Data will be presented that covers physical and chemical properties of the phosphazenes as well as the properties when blended at various levels with representative organic carbonate baseline solvents. Electrochemical cycling data will be presented using commercially available electrode couples as well as studies focusing on cell performance at early lifetime as well as after repeated cycles. Conclusions regarding the effect of the unsaturated phosphazene compounds and their interaction with various alkyl carbonates, and their effect on cell performance will be presented.

  10. Unsaturated Phosphazenes as Co-Solvents for Lithium-Ion Battery Electrolytes

    SciTech Connect

    Harrup, Mason K; Rollins, Harry W.; Jamison, David K.; Dufek, Eric J; Gering, Kevin L; Luther, Thomas A

    2014-07-24

    This paper covers the synthesis and use of a related family of cyclic phosphazene solvents containing terminal unsaturations. A brief synopsis on the synthesis and purification of these compounds is given. Data will be presented that covers physical and chemical properties of the phosphazenes as well as the properties when blended at various level with representative organic carbonate baseline solvents. Cycling data will be presented using commercially available electrode couples (LRMR/C) as well as studies focusing on cell performance at early lifetime as well as after repeated cycles. Conclusions regarding the effect of the unsaturated phosphazene compounds and their interaction with various alkyl carbonates, and their effect on cell performance will be presented.

  11. Organic-solvent-tolerant bacterium which secretes organic-solvent-stable lipolytic enzyme

    SciTech Connect

    Ogino, Hiroyasu; Miyamoto, Kazuhiro; Ishikawa, Haruo )

    1994-10-01

    A bacterial strain which could be grown in a medium containing organic solvents and which could secrete lipolytic enzyme was isolated. The stability of the lipolytic activity of the supernatant of the culture increased significantly in the presence of organic solvents such as toluene, cyclohexane, ethanol, and acetone. 11 refs., 1 fig., 2 tabs.

  12. Effect of solvents, solvent mixture and silver nanoparticles on photophysical properties of a ketocyanine dye.

    PubMed

    Thipperudrappa, J; Deepa, H R; Raghavendra, U P; Hanagodimath, S M; Melavanki, R M

    2017-02-01

    The effect of solvents of varying polarity and hydrogen bonding ability, solvent mixture and silver nanoparticles on the photophysical properties of a ketocyanine dye, 2,5-di[(E)-1-(4-diethylaminophenyl) methylidine]-1-cyclopentanone (2,5-DEAPMC), is investigated at room temperature. Solvent effect is analyzed using Lippert-Mataga bulk polarity function, Reichardt's microscopic solvent polarity parameter, and Kamlet's and Catalan's multiple linear regression approaches. The spectral properties better follow Reichardt's microscopic solvent polarity parameter than the Lippert-Mataga bulk polarity function. This indicates that both general and specific solute-solvent interactions are operative. Kamlet's and Catalan's multiple linear regression approaches indicate that polarizability/dipolarity solvent influences are greater than hydrogen bond donor and hydrogen bond acceptor solvent influences. The solvatochromic correlations are used to estimate excited state dipole moment using the experimentally determined ground state dipole moment. The excited state dipole moment of the dye is found to be larger than its corresponding ground state dipole moment and ground and excited state dipole moments are not parallel, but subtend an angle of 77°. The absorption and emission spectra are modulated in the presence silver nanoparticles. The fluorescence of 2,5-DEAPMC is quenched by silver nanoparticles. The possible fluorescence quenching mechanisms are discussed. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Changes in psychological performances of solvent-poisoned and solvent-exposed workers

    SciTech Connect

    Lindstroem, K.

    1980-01-01

    The changes in psychological performances associated with long-term exposure to organic solvents and solvent mixtures were studied in a group of 56 male workers diagnosed as having an occupational disease caused by solvents. Their mean duration of exposure was 9.1 +/- SD 8.3 years, and they were exposed mainly to halogenated and aromatic hydrocarbons and to mixtures of paint solvents. The psychological performances of these solvent-exposed patients were compared with those of 98 styrene-exposed workers and a nonexposed group of 43 construction workers. The applied psychological test variables were factor analyzed, before other statistical analysis, in order to clarify what they measured in the present study. The solvent-exposed group was characterized by a decline in visuomotor performance and decreased freedom from distractibility. The poor visuomotor performances were also related to the long duration of solvent exposure in this group of patients. The index applied for the exposure level revealed no significant relationships to psychological performances among the solvent-exposed patients. The psychological performances of the styrene-exposed group differed only very slightly from those of the nonexposed workers.

  14. Solvent System Selection Strategies in Countercurrent Separation

    PubMed Central

    Liu, Yang; Friesen, J. Brent; McAlpine, James B.; Pauli, Guido F.

    2015-01-01

    The majority of applications in countercurrent and centrifugal partition chromatography, collectively known as countercurrent separation, are dedicated to medicinal plant and natural product research. In countercurrent separation, the selection of the appropriate solvent system is of utmost importance as it is the equivalent to the simultaneous choice of column and eluent in liquid chromatography. However, solvent system selection is often laborious, involving extensive partition and/or analytical trials. Therefore, simplified solvent system selection strategies that predict the partition coefficients and, thus, analyte behavior are in high demand and may advance both the science of countercurrent separation and its applications. The last decade of solvent system selection theory and applications are critically reviewed, and strategies are classified according to their data input requirements. This offers the practitioner an up-to-date overview of rationales and methods for choosing an efficient solvent system, provides a perspective regarding their accuracy, reliability, and practicality, and discusses the possibility of combining multiple methods for enhanced prediction power. PMID:26393937

  15. Non-aqueous cleaning solvent substitution

    NASA Technical Reports Server (NTRS)

    Meier, Gerald J.

    1994-01-01

    A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of AlliedSignal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, was selected as the solvent of choice, and it was found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally-safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

  16. Solvent gating of intramolecular electron transfer

    SciTech Connect

    Miller, R.M. ); Spears, K.G.; Gong, J.H.; Wach, M. )

    1994-02-03

    The rates for ionic photodissociation of malachite green leucocyanide to form cyanide ion and a malachite green carbonium ion were measured as a function of solvent and temperature. The observed rates in mixtures of polar and nonpolar solvents all had an activation energy of about 1 kcal/mol for a wide range of dielectric constants. This dissociative intramolecular electron transfer (DIET) is unusual because it is the first example where solvent configurational entropy changes are required to enable a large amplitude molecular distortion leading to a nonadiabatic electron transfer and ionic dissociation. This solvent gated intramolecular electron-transfer mechanism is supported by analysis of the preexponential and activation energy trends in dipolar aprotic solven mixtures and alcohol solvents. The large amplitude motion is not separately measurable due to the slow gating rates, but viscosity effects on both the preexponential and the activation energy are analyzed to demonstrate consistency with a barrierless diffusion model having a structural dependence on electron-transfer rate. The rate has an inverse dependence on viscosity raised to the 0.53 power. 36 refs., 6 figs., 4 tabs.

  17. Solvent response of mixed polymer brushes

    NASA Astrophysics Data System (ADS)

    Gong, Kai; Chapman, Walter G.

    2011-12-01

    We have performed classical density functional theory calculations to study the behavior of mixed polymer brushes tethered to a planar surface. We assume no lateral segregation of the polymer at the grafting density studied and consider an implicit solvent. For a binary mixture of short and long athermal polymer chains, the short chain is compressed while the long chain is stretched compared with corresponding pure polymer chains at the same grafting density, which is consistent with simulation. This results from configurational entropy effects. Furthermore, we add a mean-field interaction for each polymer brush to simulate their different response towards a solvent. The long chain is forced to dislike the solvent more than the short chain. Through the interplay between the solvent effects and configurational entropy effects, a switch of the polymer brush surface (or outer) layer is found with increasing chain length of the long chain. The transition chain length (long chain) increases with increasing the solvent selectivity, and decreases with increasing the grafting density of the long chain. These results can provide guidance for the design of smart materials based on mixed polymer brushes.

  18. Development of deep eutectic solvents applied in extraction and separation.

    PubMed

    Li, Xiaoxia; Row, Kyung Ho

    2016-09-01

    Deep eutectic solvents, as an alternative to ionic liquids, have greener credentials than ionic liquids, and have attracted considerable attention in related chemical research. Deep eutectic solvents have attracted increasing attention in chemistry for the extraction and separation of various target compounds from natural products. This review highlights the preparation of deep eutectic solvents, unique properties of deep eutectic solvents, and synthesis of deep-eutectic-solvent-based materials. On the other hand, application in the extraction and separation of deep eutectic solvents is also included in this report. In this paper, the available data and references in this field are reviewed to summarize the applications and developments of deep eutectic solvents. Based on the development of deep eutectic solvents, an exploitation of new deep eutectic solvents and deep eutectic solvents-based materials is expected to diversify into extraction and separation.

  19. Chlorinated solvent replacements recycle/recovery review report

    SciTech Connect

    Beal, M.; Hsu, D.; McAtee, R.E.; Weidner, J.R. ); Berg, L.; McCandless, F.P.; Waltari, S.; Peterson, C. . Dept. of Chemical Engineering)

    1992-08-01

    This report is a literature review of waste solvents recycle/recovery methods and shows the results of solvent separations using membrane and distillation technologies. The experimental solvent recovery methods were conducted on solvent replacements for chlorinated solvents at Montana State University. The literature review covers waste solvents separation using distillation, membranes decantation, filtration, carbon adsorption, solvent extraction, and other vapor-phase separation techniques. The results of this study identify solvent distillation methods as the most common separation technique. The alternative separation methods typically supplement distillation. The study shows the need for industries to identify waste solvent disposal methods and investigate the economics of waste solvent recycling as a possible waste reduction method.

  20. Solvent-dependent electrical characteristics and stability of organic thin-film transistors with drop cast bis(triisopropylsilylethynyl) pentacene

    NASA Astrophysics Data System (ADS)

    Kim, Chang Su; Lee, Stephanie; Gomez, Enrique D.; Anthony, John E.; Loo, Yueh-Lin

    2008-09-01

    The solvent from which the active layer is drop cast dramatically influences the electrical characteristics and electrical stability of thin-film transistors comprising bis(triisopropylsilylethynyl) pentacene. Casting from high boiling solvents allows slower crystallization; devices cast from toluene and chlorobenzene thus exhibit mobilities >0.1 cm2/V s and on/off ratios of ˜106. More importantly, the solvent choice influences the device stability. Devices from toluene exhibit stable characteristics, whereas devices from chlorobenzene show hystereses on cycling, with dramatic threshold voltage shifts toward positive voltages. The instability in chlorobenzene devices is attributed to the migration of water and solvent impurities to the charge transport interface on repetitive testing.