Science.gov

Sample records for cycling absorption process

  1. Materials performance in prototype Thermal Cycling Absorption Process (TCAP) columns

    SciTech Connect

    Clark, E.A.

    1992-11-21

    Two prototype Thermal Cycling Absorption Process (TCAP) columns have been metallurgically examined after retirement, to determine the causes of failure and to evaluate the performance of the column container materials in this application. Leaking of the fluid heating and cooling subsystems caused retirement of both TCAP columns, not leaking of the main hydrogen-containing column. The aluminum block design TCAP column (ABL block TCAP) used in the Advanced Hydride Laboratory, Building 773-A, failed in one nitrogen inlet tube that was crimped during fabrication, which lead to fatigue crack growth in the tube and subsequent leaking of nitrogen from this tube. The Third Generation stainless steel design TCAP column (Third generation TCAP), operated in 773-A room C-061, failed in a braze joint between the freon heating and cooling tubes (made of copper) and the main stainless steel column. In both cases, stresses from thermal cycling and local constraint likely caused the nucleation and growth of fatigue cracks. No materials compatibility problems between palladium coated kieselguhr (the material contained in the TCAP column) and either aluminum or stainless steel column materials were observed. The aluminum-stainless steel transition junction appeared to be unaffected by service in the AHL block TCAP. Also, no evidence of cracking was observed in the AHL block TCAP in a location expected to experience the highest thermal shock fatigue in this design. It is important to limit thermal stresses caused by constraint in hydride systems designed to work by temperature variation, such as hydride storage beds and TCAP columns.

  2. Materials performance in prototype Thermal Cycling Absorption Process (TCAP) columns

    SciTech Connect

    Clark, E.A.

    1992-11-21

    Two prototype Thermal Cycling Absorption Process (TCAP) columns have been metallurgically examined after retirement, to determine the causes of failure and to evaluate the performance of the column container materials in this application. Leaking of the fluid heating and cooling subsystems caused retirement of both TCAP columns, not leaking of the main hydrogen-containing column. The aluminum block design TCAP column (AHL block TCAP) used in the Advanced Hydride Laboratory, Building 773-A, failed in one nitrogen inlet tube that was crimped during fabrication, which lead to fatigue crack growth in the tube and subsequent leaking of nitrogen from this tube. The Third Generation stainless steel design TCAP column (Third generation TCAP), operated in 773-A room C-061, failed in a braze joint between the freon heating and cooling tubes (made of copper) and the main stainless steel column. In both cases, stresses from thermal cycling and local constraint likely caused the nucleation and growth of fatigue cracks. No materials compatibility problems between palladium coated kieselguhr (the material contained in the TCAP column) and either aluminum or stainless steel column materials were observed. The aluminum-stainless steel transition junction appeared to be unaffected by service in the AHL block TCAP. Also, no evidence of cracking was observed in the AHL block TCAP in a location expected to experience the highest thermal shock fatigue in this design. It is important to limit thermal stresses caused by constraint in hydride systems designed to work by temperature variation, such as hydride storage beds and TCAP columns.

  3. Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

    DOE PAGES

    Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

    2015-02-01

    The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production system’s footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

  4. Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

    SciTech Connect

    Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

    2015-02-01

    The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production system’s footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

  5. Thermal Cycling Absorption Process (TCAP): Instrument and Simulation Development Status at Los Alamos National Laboratory

    SciTech Connect

    Arias, Angela A.; Schmierer, Eric N.; Gettemy, Donald; Howard, David W.; Wermer, Joseph R.; Tuggle, Dale G.

    2005-07-15

    The Thermal Cycling Absorption Process (TCAP) Project at Los Alamos National Laboratory has been a collaborative effort with Savannah River Site to demonstrate the Tube-in-Tube (TnT) column design and to improve TCAP science. TnT TCAP is an alternative design which uses a liquid to thermally cycle the metal hydride packed column. Inert gas displacement tests and deuterium pulse tests have been performed on the TnT TCAP column. The inert gas displacement tests are designed to measure plug flow in the column while the deuterium pulse tests determine the separation ability of the column. A residual gas analyzer measures the gases in the exit stream and the experimental results are compared with pulse test model results.

  6. Recent advances in SRS on hydrogen isotope separation using thermal cycling absorption process

    SciTech Connect

    Xiao, X.; Kit Heung, L.; Sessions, H.T.

    2015-03-15

    TCAP (Thermal Cycling Absorption Process) is a gas chromatograph in principle using palladium in the column packing, but it is unique in the fact that the carrier gas, hydrogen, is being isotopically separated and the system is operated in a semi-continuous manner. TCAP units are used to purify tritium. The recent TCAP advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10 of the current production system's footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects.

  7. Enhanced absorption cycle computer model

    NASA Astrophysics Data System (ADS)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  8. Advanced regenerative absorption refrigeration cycles

    DOEpatents

    Dao, Kim

    1990-01-01

    Multi-effect regenerative absorption cycles which provide a high coefficient of performance (COP) at relatively high input temperatures. An absorber-coupled double-effect regenerative cycle (ADR cycle) (10) is provided having a single-effect absorption cycle (SEA cycle) (11) as a topping subcycle and a single-effect regenerative absorption cycle (1R cycle) (12) as a bottoming subcycle. The SEA cycle (11) includes a boiler (13), a condenser (21), an expansion device (28), an evaporator (31), and an absorber (40), all operatively connected together. The 1R cycle (12) includes a multistage boiler (48), a multi-stage resorber (51), a multisection regenerator (49) and also uses the condenser (21), expansion device (28) and evaporator (31) of the SEA topping subcycle (11), all operatively connected together. External heat is applied to the SEA boiler (13) for operation up to about 500 degrees F., with most of the high pressure vapor going to the condenser (21) and evaporator (31) being generated by the regenerator (49). The substantially adiabatic and isothermal functioning of the SER subcycle (12) provides a high COP. For higher input temperatures of up to 700 degrees F., another SEA cycle (111) is used as a topping subcycle, with the absorber (140) of the topping subcycle being heat coupled to the boiler (13) of an ADR cycle (10). The 1R cycle (12) itself is an improvement in that all resorber stages (50b-f) have a portion of their output pumped to boiling conduits (71a-f) through the regenerator (49), which conduits are connected to and at the same pressure as the highest pressure stage (48a) of the 1R multistage boiler (48).

  9. Advanced absorption heat pump cycles

    NASA Astrophysics Data System (ADS)

    Reimann, R. C.

    The main goal is the development of significantly improved absorption machinery. This was to be directed specifically towards the development of a direct natural gas-fired absorption heat pump with both heating and cooling efficiencies advanced beyond current commercial offerings. These were to be accomplished through the use of novel and superior cycles, or by improved component performance. To keep the focus on machinery, the stipulation was agreed that candidate absorbent-refrigerant combinations were to be selected from among those whose properties were adequately known to permit cycle calculations and preliminary machine layouts.

  10. Enhanced absorption cycle computer model. Final report

    SciTech Connect

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperatures boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorptions systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system`s components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H{sub 2}O triple-effect cycles, LiCl-H{sub 2}O solar-powered open absorption cycles, and NH{sub 3}-H{sub 2}O single-effect and generator-absorber heat exchange cycles. An appendix contains the User`s Manual.

  11. Gas-absorption process

    DOEpatents

    Stephenson, Michael J.; Eby, Robert S.

    1978-01-01

    This invention is an improved gas-absorption process for the recovery of a desired component from a feed-gas mixture containing the same. In the preferred form of the invention, the process operations are conducted in a closed-loop system including a gas-liquid contacting column having upper, intermediate, and lower contacting zones. A liquid absorbent for the desired component is circulated through the loop, being passed downwardly through the column, regenerated, withdrawn from a reboiler, and then recycled to the column. A novel technique is employed to concentrate the desired component in a narrow section of the intermediate zone. This technique comprises maintaining the temperature of the liquid-phase input to the intermediate zone at a sufficiently lower value than that of the gas-phase input to the zone to effect condensation of a major part of the absorbent-vapor upflow to the section. This establishes a steep temperature gradient in the section. The stripping factors below this section are selected to ensure that virtually all of the gases in the downflowing absorbent from the section are desorbed. The stripping factors above the section are selected to ensure re-dissolution of the desired component but not the less-soluble diluent gases. As a result, a peak concentration of the desired component is established in the section, and gas rich in that component can be withdrawn therefrom. The new process provides important advantages. The chief advantage is that the process operations can be conducted in a single column in which the contacting zones operate at essentially the same pressure.

  12. Quasar Absorption Line Survey - Cycle 4 High

    NASA Astrophysics Data System (ADS)

    Bahcall, John

    1994-01-01

    The Absorption Line Survey of bright quasars provides a homogeneous data base for studying fundamental questions about the origin and evolution of gaseous systems in the universe. The initial results determine at small redshifts the number densities of Ly-ALPHA systems, of metal-lines and extragalactic halos, of Lyman-limit systems, of associated absorption systems, and the shapes and intensities of quasar emission lines and spectral energy distributions. The survey reveals that much of the sky is covered by high or very high velocity metal-line clouds present in the Galactic halo. A larger sample, which includes the requested Cycle 3 observations, is required to answer many important questions. For example, what is the correlation function of Ly-ALPHA systems at small redshifts? What fraction of the metal, the Ly-ALPHA, and the Ly-limit systems are associated with galaxies and what are the characteristic sizes of the outer gaseous regions of different types of galaxies? Do absorbing systems show evidence of the large-scale structure seen with galaxies and clusters of galaxies? The observations requested in Cycle 3 will extend the region of coverage of the Key Project sample from the redshift range of z = 0.0 to 1.0 (Cycles 1& 2) to z = 0.0 to 1.6 (Cycles 1-3). THIS FILE CONTAINS THE HIGH PRIORITY OBSERVATIONS FROM CYCLES 2 and 3 WHICH WERE NOT COMPLETED IN THOSE CYCLES.

  13. Preformance Analysis of NH3-H2O Absorption Cycle

    NASA Astrophysics Data System (ADS)

    Tsujimori, Atsushi; Ozaki, Eiichi

    Different from H2O-LiBr absorption cycle, it is necessary to have rectifier between generator and condenser in NH3-H2O absorption cycle, because there mixes some steam in refrigerant vapor in the process of regenerating refrigerant from the ammonia strong aqueous solution. And in some case ex. partial load or heating, the efficiency of rectifier might decrease, if the flow rate of refrigerant vapor and ammonia aqueous solution decrease. As a result, steam flow into condenser with ammonia refrigerant vapor, which reduces cycle COPs of cooling and heating. Accordingly in order to evaluate the effect of ammonia concentration in refrigerant for the performance of NH3-H2O absorption heat pump, the simple design approach of modeling condenser and evaporator is introduced in this paper. In the model, the calculation of heat rate in condenser and evaporator was simplified considering the characteristic of NH3-H2O liquid-vapor equilibrium. Then the simulation for cycle perforance based on GAX absorption cycle was made using the efficiency of rectifier that established the ammonia concentration in refrigerant and it was derived that 3 [%] decrease of ammonia concentration in refrigerant induced 15 [%] decrcase of cooling COP and 7 [%] decrease of heating COP and that there existed the most suitable circulation ratio for each ammonia concentration in refrigerant.

  14. 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.

  15. 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.

  16. Performance Characteristics of Absorption Hybrid Cycle Introduced Compressor

    NASA Astrophysics Data System (ADS)

    Iyoki, Shigeki; Kotani, Yuji; Uemura, Tadashi

    In this paper, four kinds of absorption hybrid cycle which introduced the compressor in the absorption cycle were proposed. As basic cycle of absorption refrigerating machine, the following were chosen: two kinds of single-stage absorption refrigerating machine and two kinds of double effect absorption refrigerating machine. As a working medium-absorbent system, NH3-H2O system, C2H5NH2-H2O system and C2H5NH2-H2O-LiBr system were adopted. Using these three kinds of working medium-absorbent system, the performance characteristics of four kinds of absorption hybrid cycle were simulated. And the performance characteristics of these cycles were compared.

  17. Dilution cycle control for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    A dilution cycle control system for an absorption refrigeration system is disclosed. The control system includes a time delay relay for sensing shutdown of the absorption refrigeration system and for generating a control signal only after expiration of a preselected time period measured from the sensed shutdown of the absorption refrigeration system, during which the absorption refrigeration system is not restarted. A dilution cycle for the absorption refrigeration system is initiated in response to generation of a control signal by the time delay relay. This control system is particularly suitable for use with an absorption refrigeration system which is frequently cycled on and off since the time delay provided by the control system prevents needless dilution of the absorption refrigeration system when the system is turned off for only a short period of time and then is turned back on.

  18. Fundamental Study of Absorption Cycle without Electric Solution Pump

    NASA Astrophysics Data System (ADS)

    Tsujimori, Atsushi; Sato, Kazuo; Nakao, Kazushige; Ohgushi, Tetsuro; Katsuta, Masafumi

    The absorption refrigerant cycle has been used in Japan, as energy shortage problem is more and more serious and environmental protection is of increasing importance. This type of air conditioner and chiller consume less electric power input than the electric one. However, the absorption refrigerator of large cooling capacity consumes some electric power with the required facility. Then in this research, the absorption cycle without the electric solution pump is proposed using a capillary pump and the possibility of making this cycle running using LiBr solution as a working fluid is investigated. As a result, it was found that the absorption cycle could be reached using a capillary wick in the generator to circulate the refrigerant and kept the strong and weak solution low pressure.

  19. Integrated vacuum absorption steam cycle gas separation

    DOEpatents

    Chen, Shiaguo [Champaign, IL; Lu, Yonggi [Urbana, IL; Rostam-Abadi, Massoud [Champaign, IL

    2011-11-22

    Methods and systems for separating a targeted gas from a gas stream emitted from a power plant. The gas stream is brought into contact with an absorption solution to preferentially absorb the targeted gas to be separated from the gas stream so that an absorbed gas is present within the absorption solution. This provides a gas-rich solution, which is introduced into a stripper. Low pressure exhaust steam from a low pressure steam turbine of the power plant is injected into the stripper with the gas-rich solution. The absorbed gas from the gas-rich solution is stripped in the stripper using the injected low pressure steam to provide a gas stream containing the targeted gas. The stripper is at or near vacuum. Water vapor in a gas stream from the stripper is condensed in a condenser operating at a pressure lower than the stripper to concentrate the targeted gas. Condensed water is separated from the concentrated targeted gas.

  20. 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.

  1. Some heat pump concepts for residual heat utilization. [Absorption-cycle and open-cycle systems

    SciTech Connect

    Perez-Blanco, H.; Chen, F. C.

    1980-01-01

    Large quantities of low temperature heat in the industrial sector are rejected in the cooling water, condensate, and process water streams. While the energy rejected in these streams at temperatures between 40 and 80/sup 0/C amounts to 2.95 x 10/sup 9/ GJ/y, 2.42 x 10/sup 9/ GJ/y of process energy in the form of hot water and steam are needed in the United States. Industrial heat pumps, that recover the low temperature heat energy and upgrade it to a more usable temperature level, may improve the energy supply and demand situation. Two heat activated heat pump concepts - an absorption cycle system and an open cycle system are analyzed from the conceptual systems design and energy savings point of view. The results of the analysis and further research needs are presented.

  2. Performance Characteristics of Hybrid Cycle Combined Absorption Heat Transformer and Absorption Refrigerating Machine

    NASA Astrophysics Data System (ADS)

    Iyoki, Shigeki; Otsuka, Shin-Ichi; Uemura, Tadashi

    In this paper, four kinds of hybrid cycles which combined the single-stage absorption refrigerating machine and four kinds of absorption heat transformers were proposed. It is possible that each of these hybrid cycles gets high temperature and low temperature from one cycle, simultaneously. As basic cycle of absorption heat transformer, the following were chosen: two kinds of single-stage absorption heat transformer and two kinds of two-stage absorption heat transformer. As a working medium-absorbent system, H2O-LiBr system, H2O-LiBr-LiNO3 system, H2O-LiBr-LiNO3-LiCl system, H2O-LiBr-C2H6O2 system and H2O-LiNO3-LiCl system were adopted. Using these five kinds of working medium-absorbent system, the performance characteristics of four kinds of hybrid cycle were simulated. And the performance characteristics of these cycles were compared.

  3. Cycle Simulation of HotWater Fired Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Esaki, Shuji; Iramina, Kazuyasu; Kobayashi, Takahiro; Ohnou, Masayuki; Kaneko, Toshiyuki; Soga, Takashi

    The design limits were examined to determine the lowest temperature for hot water that can be used as a heat source to drive a hot water fired absorption chiller. Advantage was taken of the fact that the cycle calculation method using the minimum temperature difference is quite effective. This minimum temperature difference was the lower of the two temperature differences used to get the logarithmic mean temperature difference that need to design the evaporator, absorber, condenser and generator in an absorption refrigerator. This report proposes a new solution algorithm employing this minimum temperature difference to make a cycle simulation of the hot water fired absorption chiller. It shows the lowest usable temperature for hot water and makes clear the chilled water and cooling water temperature conditions that can provide the lowest temperature.

  4. Simulation and performance analysis of triple-effect absorption cycles

    SciTech Connect

    Grossman, G.; Wilk, M.; DeVault, R.C.

    1993-08-01

    Performance simulation has been carried out for several triple-effect cycles, designed to improve utilization of high temperature heat sources for absorption systems and capable of substantial performance improvement over equivalent double-effect cycles. The systems investigated include the three-condenser-three-desorber (3C3D) cycle, forming an extension of the conventional double-effect one; the recently proposed Double Condenser Coupled (DCC) cycle which recovers heat from the hot condensate leaving the high temperature condensers and adds it to the lower temperature desorbers; and the dual loop cycle comprising two complete single-effect loops, recovering heat from the condenser and absorber of one loop to the desorber of the other loop and generating a cooling effect in the evaporators of both loops. A modular computer code for simulation of absorption systems was used to investigate the performances of the cycles and compare them on an equivalent basis, by selecting a common reference design and operating condition. Performance simulation was carried out over a range of operating conditions, including some investigation of the influence of the design parameters. Coefficients of performance ranging from 1.27 for the series-flow 3C3D to 1.73 for the parallel-flow DCC have been calculated at the design point. The relative merits and shortcomings of the different cycle configurations has been studied.

  5. Air Quality Management Process Cycle

    EPA Pesticide Factsheets

    Air quality management are activities a regulatory authority undertakes to protect human health and the environment from the harmful effects of air pollution. The process of managing air quality can be illustrated as a cycle of inter-related elements.

  6. Sulphur trioxide absorption apparatus and process

    SciTech Connect

    Cameron, G.M.

    1987-03-31

    This patent describes a contact process for producing a concentrated sulphuric acid from dry sulphur dioxide and oxygen containing mixtures which employs the absorption of sulphur trioxide from a hot, dry gas stream containing sulphur trioxide into at least one sulphuric acid stream. The improvement described here comprises: (a) feeding the gas stream to a lower packed absorption zone contained within an absorption tower; (b) feeding a first sulphuric acid stream to the lower absorption zone to effect absorption of a major portion of the sulphur trioxide from the gas stream into the first sulphuric acid stream to produce a first enriched sulphuric acid stream and a depleted sulphur trioxide gas stream; (c) feeding the depleted sulphur trioxide gas stream to an upper packed absorption zone above the lower absorption zone within the tower; and (d) feeding a second sulphuric acid stream to the upper absorption zone to effect absorption of substantially all of the sulphur trioxide remaining in the depleted sulphur trioxide gas stream to produce a second enriched sulphuric acid stream and a substantially sulphur trioxide-free gas stream.

  7. Cascade Reverse Osmosis Air Conditioning System: Cascade Reverse Osmosis and the Absorption Osmosis Cycle

    SciTech Connect

    2010-09-01

    BEETIT Project: Battelle is developing a new air conditioning system that uses a cascade reverse osmosis (RO)-based absorption cycle. Analyses show that this new cycle can be as much as 60% more efficient than vapor compression, which is used in 90% of air conditioners. Traditional vapor-compression systems use polluting liquids for a cooling effect. Absorption cycles use benign refrigerants such as water, which is absorbed in a salt solution and pumped as liquid—replacing compression of vapor. The refrigerant is subsequently separated from absorbing salt using heat for re-use in the cooling cycle. Battelle is replacing thermal separation of refrigerant with a more efficient reverse osmosis process. Research has shown that the cycle is possible, but further investment will be needed to reduce the number of cascade reverse osmosis stages and therefore cost.

  8. Waste heat driven absorption refrigeration process and system

    DOEpatents

    Wilkinson, William H.

    1982-01-01

    Absorption cycle refrigeration processes and systems are provided which are driven by the sensible waste heat available from industrial processes and other sources. Systems are disclosed which provide a chilled water output which can be used for comfort conditioning or the like which utilize heat from sensible waste heat sources at temperatures of less than 170.degree. F. Countercurrent flow equipment is also provided to increase the efficiency of the systems and increase the utilization of available heat.

  9. Carbon dioxide absorption methanol process

    SciTech Connect

    Apffel, F.

    1989-08-29

    This patent describes a process for removing carbon dioxide from a feed stream of natural gas having at least methane, ethane and heavier. It comprises: first, separating the feed stream in a first separator to form a first stream having substantially all of the propane and heavier hydrocarbons and carbon dioxide and ethane and a second stream, having methane, carbon dioxide and ethane; separating the second stream in a second separator into a stream of carbon dioxide product and a third stream having ethane, methane and carbon dioxide: mixing at least a portion of the third stream with a polar compound; stream after the mixing in an absorber; separating the vapor and liquid of the third stream after the mixing in an absorber; absorbing the remaining unabsorbed carbon dioxide in a lean portion of the polar compound in the absorber, the absorber carbon dioxide and ethane with the polar; separating the first stream in a third separator to separate the propane and heavier hydrocarbons from the carbon dioxide and ethane, which carbon dioxide and ethane forms a fifth stream; and separating the polar compound/carbon dioxide effluent of the absorber in a fourth separator, to separate the carbon dioxide from the polar compound, the polar compound forming a sixth stream.

  10. Carbon dioxide absorption methanol process

    SciTech Connect

    Apffel, F.P.

    1987-06-23

    A process is described for removing carbon dioxide from a feed stream of natural gas, having at least methane, ethane and heavier hydrocarbon, comprising: separating the feed stream in a first separator to form a first stream, having substantially all of the propane and heavier hydrocarbons and carbon dioxide and ethane, and a second stream, having methane, carbon dioxide and ethane; mixing the second stream with a polar compound to form a third stream; separating the vapor and liquid of the third stream in the bottom portion of an absorber; absorbing carbon dioxide and ethane from the separated vapor of Step C in a lean portion of the polar compound in the absorber, the absorber carbon dioxide and ethane forming a fourth stream; separating the ethane from the polar compound and carbon dioxide in a separator; separating the first stream in a third separator to separate the propane and heavier hydrocarbons from the carbon dioxide and ethane: carbon dioxide and ethane forms a fifth stream; and separating the polar compound/carbon dioxide effluent of the second separator in a fourth separator, to separate the carbon dioxide from the polar compound. The polar compound forming a sixth stream.

  11. Cycle Analysis using Exhaust Heat of SOFC and Turbine Combined Cycle by Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Takezawa, Shinya; Wakahara, Kenji; Araki, Takuto; Onda, Kazuo; Nagata, Susumu

    A power generating efficiency of solid oxide fuel cell (SOFC) and gas turbine combined cycle is fairly high. However, the exhaust gas temperature of the combined cycle is still high, about 300°C. So it should be recovered for energy saving, for example, by absorption chiller. The energy demand for refrigeration cooling is recently increasing year by year in Japan. Then, we propose here a cogeneration system by series connection of SOFC, gas turbine and LiBr absorption chiller to convert the exhaust heat to the cooling heat. As a result of cycle analysis of the combined system with 500kW class SOFC, the bottoming single-effect absorption chiller can produce the refrigerating capacity of about 120kW, and the double-effect absorption chiller can produce a little higher refrigerating capacity of about 130kW without any additional fuel. But the double-effect absorption chiller became more expensive and complex than the single-effect chiller.

  12. Technology development life cycle processes.

    SciTech Connect

    Beck, David Franklin

    2013-05-01

    This report and set of appendices are a collection of memoranda originally drafted in 2009 for the purpose of providing motivation and the necessary background material to support the definition and integration of engineering and management processes related to technology development. At the time there was interest and support to move from Capability Maturity Model Integration (CMMI) Level One (ad hoc processes) to Level Three. As presented herein, the material begins with a survey of open literature perspectives on technology development life cycles, including published data on %E2%80%9Cwhat went wrong.%E2%80%9D The main thrust of the material presents a rational expose%CC%81 of a structured technology development life cycle that uses the scientific method as a framework, with further rigor added from adapting relevant portions of the systems engineering process. The material concludes with a discussion on the use of multiple measures to assess technology maturity, including consideration of the viewpoint of potential users.

  13. Evaluation of absorption cycle for space station environmental control system application

    NASA Technical Reports Server (NTRS)

    Sims, W. H.; Oneill, M. J.; Reid, H. C.; Bisenius, P. M.

    1972-01-01

    The study to evaluate an absorption cycle refrigeration system to provide environmental control for the space stations is reported. A zero-gravity liquid/vapor separator was designed and tested. The results were used to design a light-weight, efficient generator for the absorption refrigeration system. It is concluded that absorption cycle refrigeration is feasible for providing space station environmental control.

  14. Structural stability of 1100{degree}C heated Pd/k during absorption cycling in protium

    SciTech Connect

    Fisher, I.A.

    1993-03-12

    Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110{degree}C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100{degree}C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the packing will cause the material to crack and degrade. The purpose of this report is to document the results of the absorption/desorption cycling of 1,100{degree}C heated Pd/k and compare these results to the results obtained from the absorption/desorption cycling of Pd/k which had not been heated at 1, 100{degree}C.

  15. Five-Photon Absorption and Selective Enhancement of Multiphoton Absorption Processes.

    PubMed

    Friese, Daniel H; Bast, Radovan; Ruud, Kenneth

    2015-05-20

    We study one-, two-, three-, four-, and five-photon absorption of three centrosymmetric molecules using density functional theory. These calculations are the first ab initio calculations of five-photon absorption. Even- and odd-order absorption processes show different trends in the absorption cross sections. The behavior of all even- and odd-photon absorption properties shows a semiquantitative similarity, which can be explained using few-state models. This analysis shows that odd-photon absorption processes are largely determined by the one-photon absorption strength, whereas all even-photon absorption strengths are largely dominated by the two-photon absorption strength, in both cases modulated by powers of the polarizability of the final excited state. We demonstrate how to selectively enhance a specific multiphoton absorption process.

  16. Five-Photon Absorption and Selective Enhancement of Multiphoton Absorption Processes

    PubMed Central

    2015-01-01

    We study one-, two-, three-, four-, and five-photon absorption of three centrosymmetric molecules using density functional theory. These calculations are the first ab initio calculations of five-photon absorption. Even- and odd-order absorption processes show different trends in the absorption cross sections. The behavior of all even- and odd-photon absorption properties shows a semiquantitative similarity, which can be explained using few-state models. This analysis shows that odd-photon absorption processes are largely determined by the one-photon absorption strength, whereas all even-photon absorption strengths are largely dominated by the two-photon absorption strength, in both cases modulated by powers of the polarizability of the final excited state. We demonstrate how to selectively enhance a specific multiphoton absorption process. PMID:26120588

  17. Absorptive capacity, technological innovation, and product life cycle: a system dynamics model.

    PubMed

    Zou, Bo; Guo, Feng; Guo, Jinyu

    2016-01-01

    While past research has recognized the importance of the dynamic nature of absorptive capacity, there is limited knowledge on how to generate a fair and comprehensive analytical framework. Based on interviews with 24 Chinese firms, this study develops a system-dynamics model that incorporates an important feedback loop among absorptive capacity, technological innovation, and product life cycle (PLC). The simulation results reveal that (1) PLC affects the dynamic process of absorptive capacity; (2) the absorptive capacity of a firm peaks in the growth stage of PLC, and (3) the market demand at different PLC stages is the main driving force in firms' technological innovations. This study also explores a sensitivity simulation using the variables of (1) time spent in founding an external knowledge network, (2) research and development period, and (3) knowledge diversity. The sensitivity simulation results show that the changes of these three variables have a greater impact on absorptive capacity and technological innovation during growth and maturity stages than in the introduction and declining stages of PLC. We provide suggestions on how firms can adjust management policies to improve their absorptive capacity and technological innovation performance during different PLC stages.

  18. 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.

  19. A Novel Absorption Cycle for Combined Water Heating, Dehumidification, and Evaporative Cooling

    SciTech Connect

    CHUGH, Devesh; Gluesenkamp, Kyle R; Abdelaziz, Omar; Moghaddam, Saeed

    2014-01-01

    In this study, development of a novel system for combined water heating, dehumidification, and space evaporative cooling is discussed. Ambient water vapor is used as a working fluid in an open system. First, water vapor is absorbed from an air stream into an absorbent solution. The latent heat of absorption is transferred into the process water that cools the absorber. The solution is then regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser. The condensed water can then be used in an evaporative cooling process to cool the dehumidified air exiting the absorber, or it can be drained if primarily dehumidification is desired. Essentially, this open absorption cycle collects space heat and transfers it to process water. This technology is enabled by a membrane-based absorption/desorption process in which the absorbent is constrained by hydrophobic vapor-permeable membranes. Constraining the absorbent film has enabled fabrication of the absorber and desorber in a plate-and-frame configuration. An air stream can flow against the membrane at high speed without entraining the absorbent, which is a challenge in conventional dehumidifiers. Furthermore, the absorption and desorption rates of an absorbent constrained by a membrane are greatly enhanced. Isfahani and Moghaddam (Int. J. Heat Mass Transfer, 2013) demonstrated absorption rates of up to 0.008 kg/m2s in a membrane-based absorber and Isfahani et al. (Int. J. Multiphase Flow, 2013) have reported a desorption rate of 0.01 kg/m2s in a membrane-based desorber. The membrane-based architecture also enables economical small-scale systems, novel cycle configurations, and high efficiencies. The absorber, solution heat exchanger, and desorber are fabricated on a single metal sheet. In addition to the open arrangement and membrane-based architecture, another novel feature of the

  20. A high-efficiency power cycle in which hydrogen is compressed by absorption in metal hydrides.

    PubMed

    Powell, J R; Salzano, F J; Yu, W S; Milau, J S

    1976-07-23

    A high-efficiency power cycle is proposed in which molecular hydrogen gas is used as a working fluid in a regenerative closed Brayton cycle. The hydrogen gas is compressed by an absorption-desorption cycle on metal hydride (FeTiH(x)) beds. Low-temperature solar or geothermal heat (temperature about 100 degrees C) is used for the compression process, and high-temperature fossil fuel or nuclear heat (temperature about 700 degrees C) supplies the expansion work in the turbine. Typically, about 90 percent of the high-temperature heat input is converted to electricity, while about 3 kilowatts of low-temperature heat is required per kilowatt of electrical output.

  1. Joint-specific power absorption during eccentric cycling.

    PubMed

    Elmer, Steven J; Madigan, Matthew L; LaStayo, Paul C; Martin, James C

    2010-02-01

    Previous investigators have reported that long term eccentric cycling increases muscle size and strength in a variety of populations. The joint-specific strategies used to absorb power during eccentric cycling, however, have not been identified. The purpose of this investigation was to determine the extent to which ankle, knee, and hip joint actions absorb power during eccentric cycling. Eight active males resisted the reverse moving pedals of an isokinetic eccentric ergometer (60 rpm) while targeting 20% of their maximum concentric cycling power. Pedal reaction forces and joint kinematics were recorded with an instrumented pedal and instrumented spatial linkage system, respectively. Joint powers were calculated using inverse dynamics; averaged over complete crank revolutions and over extension and flexion phases; and differences were assessed with a one-way ANOVA. Ankle, knee, and hip joint actions absorbed 10 (SD 3)%, 58 (SD 8)%, and 29 (SD 9)% of the total power, respectively, with 3 (SD 1)% transferred across the hip. The main power absorbing actions were eccentric knee extension (-139 (SD 21) watts), eccentric hip extension (-51 (SD 31) watts), and eccentric hip flexion (-25 (SD 6) watts). Eccentric cycling was performed with a combination of knee and hip joint actions which is consistent with submaximal concentric cycling. These data support and extend previous work that eccentric cycling improves knee extensor function and hip extensor muscle cross sectional area. Such information may allow clinicians to take even greater advantage of eccentric cycling as a rehabilitation modality. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  2. Space transportation main engine cycle assessment process

    NASA Technical Reports Server (NTRS)

    Mcconnaughey, H. V.; Lyles, G. M.

    1991-01-01

    The Advanced Launch System (ALS) program selection process for a space transportation main engine (STME) power cycle is described in terms of the methodology employed. Low cost, robustness, and high reliability are the primary parameters for engine choice, suggesting simplicity of design and efficient fabrication methods as the crucial characteristics. An evaluation methodology is developed based on the Pugh (1981) process and the King (1989) matrices. The cycle configurations considered are the gas generator (GG), the closed expander, and the open expander. The cycle assessment team determined that the GG cycle is favored by most cycle discriminators, based on an assessment of the characteristics in terms of ALS goals. The lower development risk of the GG-cycle STME is consistent with the goals of the ALS program in terms of reliability and cost efficiency.

  3. Space transportation main engine cycle assessment process

    NASA Technical Reports Server (NTRS)

    Mcconnaughey, H. V.; Lyles, G. M.

    1991-01-01

    The Advanced Launch System (ALS) program selection process for a space transportation main engine (STME) power cycle is described in terms of the methodology employed. Low cost, robustness, and high reliability are the primary parameters for engine choice, suggesting simplicity of design and efficient fabrication methods as the crucial characteristics. An evaluation methodology is developed based on the Pugh (1981) process and the King (1989) matrices. The cycle configurations considered are the gas generator (GG), the closed expander, and the open expander. The cycle assessment team determined that the GG cycle is favored by most cycle discriminators, based on an assessment of the characteristics in terms of ALS goals. The lower development risk of the GG-cycle STME is consistent with the goals of the ALS program in terms of reliability and cost efficiency.

  4. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOEpatents

    Cassano, Anthony A.

    1985-01-01

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs.

  5. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOEpatents

    Cassano, A.A.

    1985-07-02

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs. 3 figs.

  6. Operating data on a novel absorption refrigeration cycle. Progress report

    SciTech Connect

    McCluskey, R.J.

    1993-12-23

    This report describes the modifications and repairs made to the 200 ton absorption refrigeration pilot plant since April 1992, when Clarkson University assumed responsibility for it. Current operating problems and the performance of the plant, achieved to date, are detailed. Performance has been limited by small air leaks into the absorption section of the plant and by plugging in a heat exchanger which has limited the flow of purified glycol to the absorber. Nonetheless, the plant has been operated for periods of over eight hours with sustained cooling loads of 40 tons. Chilled water has been produced at a temperature as low as 38 degrees Fahrenheit. The principal leak sources have been pinpointed. Plans are described for achieving plant operation at designed levels.

  7. Absorption and Direct Processes in Chaotic Wave Scattering

    SciTech Connect

    Mendez-Sanchez, R. A.; Baez, G.; Martinez-Mares, M.

    2010-12-21

    Recent results on the scattering of waves by chaotic systems with losses and direct processes are discussed. We start by showing the results without direct processes nor absorption. We then discuss systems with direct processes and lossy systems separately. Finally the discussion of systems with both direct processes and loses is given. We will see how the regimes of strong and weak absorption are modified by the presence of the direct processes.

  8. Polarization control of intermediate state absorption in resonance-mediated multi-photon absorption process

    NASA Astrophysics Data System (ADS)

    Xu, Shuwu; Huang, Yunxia; Yao, Yunhua; Jia, Tianqing; Ding, Jingxin; Zhang, Shian; Sun, Zhenrong

    2015-07-01

    We theoretically and experimentally demonstrate the control of the intermediate state absorption in an (n + m) resonance-mediated multi-photon absorption process by the polarization-modulated femtosecond laser pulse. An analytical solution of the intermediate state absorption in a resonance-mediated multi-photon absorption process is obtained based on the time-dependent perturbation theory. Our theoretical results show that the control efficiency of the intermediate state absorption by the polarization modulation is independent of the laser intensity when the transition from the intermediate state to the final state is coupled by the single-photon absorption, but will be affected by the laser intensity when this transition is coupled by the non-resonant multi-photon absorption. These theoretical results are experimentally confirmed via a two-photon fluorescence control in (2 + 1) resonance-mediated three-photon absorption of Coumarin 480 dye and a single-photon fluorescence control in (1 + 2) resonance-mediated three-photon absorption of IR 125 dye.

  9. Comparative first- and second-law analysis of an absorption cycle

    NASA Astrophysics Data System (ADS)

    Perez-Blanco, H.; Pan, L.

    1985-07-01

    Generally, the basis of efficiency calculations and optimization studies of absorption cycles is the first law of thermodynamics. It is often argued that a first-law analysis does not produce all the information needed to optimize the absorption system. According to this line of thought, only an analysis based on the second law of thermodynamics gives the needed information. Assessment of the usefulness of second-law analysis as applied to absorption cycles seems adequate to determine the potential benefits of gathering the additional data for the absorbent-refrigerant combinations currently under consideration. To this end, a comparative first- and second-law analysis of a single-effect, lithium bromide-water absorption cycle is carried out here. An existing computer program and entropy values from the literature are used to analyze the cycle. The effects of temperature approaches in each heat exchanger and external heating/cooling fluid flow rates on the cycle performance are determined. A comparison of the results obtained via first- and second-law analyses reveals that the usefulness of the information depends on the boundaries of the system under consideration. Optimization of the absorption cycle itself, without considering the effect of external heating/cooling fluid flow rates at all, can be accomplished by first-law analysis. However, optimization of not only the cycle but also the external flow rates (i.e., the overall thermal system) is better accomplished by second-law analysis. Another interesting result of this study is that a critical temperature approach for cycle optimization can be found for the generator. In practical terms, this means that improving the heat exchanger in the generator will not always enhance the thermal performance of the cycle.

  10. Structural stability of 1100[degree]C heated Pd/k during absorption cycling in protium. [Palladium supported on kieselguhr

    SciTech Connect

    Fisher, I.A.

    1993-03-12

    Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110[degree]C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100[degree]C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the packing will cause the material to crack and degrade. The purpose of this report is to document the results of the absorption/desorption cycling of 1,100[degree]C heated Pd/k and compare these results to the results obtained from the absorption/desorption cycling of Pd/k which had not been heated at 1, 100[degree]C.

  11. 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.

  12. Dry process dependency of dupic fuel cycle

    SciTech Connect

    Park, Kwangheon; Whang, Juho; Kim, Yun-goo; Kim, Heemoon

    1996-12-31

    During the Dry Process, volatile and semi-volatile elements are released from the fuel. The effects of these released radioactive nuclides on DUPIC fuel cycle are analyzed from the view-point of radiation hazard, decay beat, and hazard index. Radiation hazard of fresh and spent DUPIC fuel is sensitive to the method of Dry Process. Decay beat of the fuel is also affected. Hazard index turned out not to be dependent on Dry Process.

  13. Thermodynamic equation of state approach for the choice of working fluids of absorption cooling cycles

    NASA Astrophysics Data System (ADS)

    Gomez, A. L.; Mansoori, G. A.

    1983-01-01

    A methodology is developed for the application of thermodynamic equations of state of fluids and fluid mixtures in evaluating working fluid combinations of absorption cooling cycles. Thermodynamic phase equilibrium formulation of this methodology is presented. In the application of this approach for the comparative study and choice of working fluids, the Redlich-Kwong equation of state is used for a number of possible working fluid combinations for solar absorption cooling cycles. It is demonstrated that when limited experimental data are at hand this approach could be a useful screening technique for potential working fluid combinations.

  14. Modeling of a Von Platen-Munters diffusion absorption refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Agostini, Bruno; Agostini, Francesco; Habert, Mathieu

    2016-09-01

    This article presents a thermodynamical model of a Von-Platen diffusion absorption refrigeration cycle for power electronics applications. It is first validated by comparison with data available in the literature for the classical water-ammonia-helium cycle for commercial absorption fridges. Then new operating conditions corresponding to specific ABB applications, namely high ambient temperature and new organic fluids combinations compatible with aluminium are simulated and discussed. The target application is to cool power electronics converters in harsh environments with high ambient temperature by providing refrigeration without compressor, for passive components losses of about 500 W, with a compact and low cost solution.

  15. Absorption of ultrasound waves during dynamic processes in disperse systems

    NASA Astrophysics Data System (ADS)

    Kol'tsova, I. S.; Khomutova, A. S.

    2016-11-01

    Measurements of ultrasound wave absorption are conducted at a frequency of 3 MHz in 3% suspensions of starch, gelatin, and lactose. It is shown that the dynamics of the additional ultrasound wave absorption coefficient in the suspensions carries information on the processes of swelling, dissolution, and the phase and structural periods occurring in the interaction of the disperse and dispersoid phases; it also reflects the influence of the temperature field on these processes.

  16. Performance Estimation of Absorption/Compression Cycle Using Working Pair Dimethyle Ether/Methanol

    NASA Astrophysics Data System (ADS)

    Endo, Naok; Maeda, Tetsuhiko; Hasegawa, Yasuo

    This paper presents the performance estimation of hybrid absorption/compression heat pump cycle, which use dimethyl ether (DME) and methanol pair as a working fluid. The disadvantage of the DME as a refrigerant is that it is flammable. But it has several advantages from the environmental aspects; toxicity is very low, and GWP is small. The first purpose of this study is to estimate the reduction of the loss of the heat exchangers, by use of absorption/compression cycle. And the second purpose is to lower the working pressure to reduce the possibility of the leakage of the working fluids. Two hybrid systems are supposed as models; one is absorption/compression system with single stage solution circuit, and another is an absorption/compression system with generator/absorber heat exchange cycle. The former cycle exceeds the cooling and heating COPs of pure DME cycle, reducing the maximum pressure about 130 kPa. And the latter system increases the heating COP by 6 to 36% with the working pressure range about 150-260 kPa.

  17. Thermodynamic modelling of a double-effect LiBr-H2O absorption refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Iranmanesh, A.; Mehrabian, M. A.

    2012-12-01

    The goal of this paper is to estimate the conductance of components required to achieve the approach temperatures, and gain insights into a double-effect absorption chiller using LiBr-H2O solution as the working fluid. An in-house computer program is developed to simulate the cycle. Conductance of all components is evaluated based on the approach temperatures assumed as input parameters. The effect of input data on the cycle performance and the exergetic efficiency are investigated.

  18. Menstrual Cycle and Visual Information Processing

    DTIC Science & Technology

    2009-04-01

    MENSTRUAL CYCLE AND VISUAL INFORMATION PROCESSING by Michelle I. Nash A thesis submitted to the faculty of Brigham Young University...APPROVAL of a thesis submitted by Michelle I. Nash This thesis has been read by each member of the following graduate committee and by majority vote...the candidate’s graduate committee, I have read the thesis of Michelle I. Nash in its final form and have found that (1) its format, citations, and

  19. Chemical process safety at fuel cycle facilities

    SciTech Connect

    Ayres, D.A.

    1997-08-01

    This NUREG provides broad guidance on chemical safety issues relevant to fuel cycle facilities. It describes an approach acceptable to the NRC staff, with examples that are not exhaustive, for addressing chemical process safety in the safe storage, handling, and processing of licensed nuclear material. It expounds to license holders and applicants a general philosophy of the role of chemical process safety with respect to NRC-licensed materials; sets forth the basic information needed to properly evaluate chemical process safety; and describes plausible methods of identifying and evaluating chemical hazards and assessing the adequacy of the chemical safety of the proposed equipment and facilities. Examples of equipment and methods commonly used to prevent and/or mitigate the consequences of chemical incidents are discussed in this document.

  20. Combined vapor compression/absorption heat pump cycles for engine-driven heat pumps

    NASA Astrophysics Data System (ADS)

    Radermacher, Reinhard; Herold, Keith E.; Howe, Lawrence A.

    1988-12-01

    The performance of three combined absorption/vapor compression cycles for gas-fired internal combustion engine driven heat pumps was theoretically assessed. Two cycles were selected for the preliminary design of breadboard systems using only off-the-shelf components. The first cycle, based on the working pair ammonia/water, is termed the simple-cycle. The second cycle, based on the working pair lithium-bromide/water, is termed the compressor enhanced double-effect chiller. Both cycles are found to be technically feasible. The coefficient of performance and the capacity are increased by up to 21 percent for cooling in the first case (compressor efficiency of 0.7) and by up to 14 percent in the second (compressor efficiency of 0.5). Both were compared against the engine drive R22 vapor compression heat pump. The performance of actual machinery for both cycles is, in the current design, hampered by the fact that the desired oil-free compressors have poor isentropic efficiencies. Oil lubricated compressors together with very effective oil separators would improve the performance of the combined LiBr/water cycle to 23 percent.

  1. Advancement of Double Effect Absorption Cycle by Input of Low Temperture Waste Heat

    NASA Astrophysics Data System (ADS)

    Kojima, Hiroshi; Akisawa, Atsushi; Kashiwagi, Takao

    Energy conservation is becoming important for global environmental protection. New simple techniques of more efficiently using the waste heat of gas co-generation systems for refrigeration are required. This paper proposes a new method of using low temperature waste heat below 100°C for refrigeration. In the new method, the low temperature waste heat is fed into the weak solution line of the double effect absorption cycle directly via an auxiliary heat exchanger. In this paper, first, the location of the auxiliary waste heat recovery heat exchanger on the solution line was studied for each solution flow type of double effect absorption cycle. Then six promising methods of recovering waste heat were selected, and moreover, the basic model was constructed and the effect of input of the low temperature waste heat was investigated for each selected method.

  2. Development and proof-testing of advanced absorption refrigeration cycle concepts

    SciTech Connect

    Modahl, R.J.; Hayes, F.C. . Applied Unitary/Refrigeration Systems Div.)

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  3. Development and proof-testing of advanced absorption refrigeration cycle concepts

    NASA Astrophysics Data System (ADS)

    Modahl, R. J.; Hayes, F. C.

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47 F and 1.2 at 17 F in the heating mode, and 0.7 at 95 F in the cooling mode, including the effect of fluid losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH3/H2O/LiBr ternary absorption fluid mixture or with the NH3/H2O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of-concept.

  4. Improvement of the COP of the LiBr-Water Double-Effect Absorption Cycles

    NASA Astrophysics Data System (ADS)

    Shitara, Atsushi

    Prevention of the global warming has called for a great necessity for energy saving. This applies to the improvement of the COP of absorption chiller-heaters. We started the development of the high efficiency gas-fired double-effect absorption chiller-heater using LiBr-H2O to achieve target performance in short or middle term. To maintain marketability, the volume of the high efficiency machine has been set below the equal to the conventional machine. The absorption cycle technology for improving the COP and the element technology for downsizing the machine is necessary in this development. In this study, the former is investigated. In this report, first of all the target performance has been set at cooling COP of 1.35(on HHV), which is 0.35 higher than the COP of 1.0 for conventional machines in the market. This COP of 1.35 is practically close to the maximum limit achievable by double-effect absorption chiller-heater. Next, the design condition of each element to achieve the target performance and the effect of each mean to improve the COP are investigated. Moreover, as a result of comparing the various flows(series, parallel, reverse)to which the each mean is applied, it has been found the optimum cycle is the parallel flow.

  5. Nitrogen cycling process rates across urban ecosystems.

    PubMed

    Reisinger, Alexander J; Groffman, Peter M; Rosi-Marshall, Emma J

    2016-09-21

    Nitrogen (N) pollution of freshwater, estuarine, and marine ecosystems is widespread and has numerous environmental and economic impacts. A portion of this excess N comes from urban watersheds comprised of natural and engineered ecosystems which can alter downstream N export. Studies of urban N cycling have focused on either specific ecosystems or on watershed-scale mass balances. Comparisons of specific N transformations across ecosystems are required to contextualize rates from individual studies. Here we reviewed urban N cycling in terrestrial, aquatic, and engineered ecosystems, and compared N processing in these urban ecosystem types to native reference ecosystems. We found that net N mineralization and net nitrification rates were enhanced in urban forests and riparian zones relative to reference ecosystems. Denitrification was highly variable across urban ecosystem types, but no significant differences were found between urban and reference denitrification rates. When focusing on urban streams, ammonium uptake was more rapid than nitrate uptake in urban streams. Additionally, reduction of stormwater runoff coupled with potential decreases in N concentration suggests that green infrastructure may reduce downstream N export. Despite multiple environmental stressors in urban environments, ecosystems within urban watersheds can process and transform N at rates similar to or higher than reference ecosystems. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Life cycle test of the NOXSO process

    SciTech Connect

    Ma, W.T.; Haslbeck, J.L.; Neal, L.G.

    1990-05-01

    This paper summarizes the data generated by the NOXSO Life Cycle Test Unit (LCTU). The NOXSO process is a dry flue gas treatment system that employs a reusable sorbent. The sorbent consists of sodium carbonate impregnated on a high-surface-area gamma alumina. A fluidized bed of sorbent simultaneously removes SO{sub 2} and NO{sub x} from flue gas at a temperature of 250{degrees}F. The spent sorbent is regenerated for reuse by treatment at high temperature with a reducing gas. This regeneration reduces sorbed sulfur compounds to SO{sub 2}, H{sub 2}S, and elemental sulfur. The SO{sub 2} and H{sub 2}S are then converted to elemental sulfur in a Claus-type reactor. The sulfur produced is a marketable by-product of the process. Absorbed nitrogen oxides are decomposed and evolved on heating the sorbent to regeneration temperature.

  7. Cascaded process model based control: packed absorption column application.

    PubMed

    Govindarajan, Anand; Jayaraman, Suresh Kumar; Sethuraman, Vijayalakshmi; Raul, Pramod R; Rhinehart, R Russell

    2014-03-01

    Nonlinear, adaptive, process-model based control is demonstrated in a cascaded single-input-single-output mode for pressure drop control in a pilot-scale packed absorption column. The process is shown to be nonlinear. Control is demonstrated in both servo and regulatory modes, for no wind-up in a constrained situation, and for bumpless transfer. Model adaptation is demonstrated and shown to provide process insight. The application procedure is revealed as a design guide to aid others in implementing process-model based control.

  8. Trait absorption is related to enhanced emotional picture processing and reduced processing of secondary acoustic probes.

    PubMed

    Benning, Stephen D; Rozalski, Vincent; Klingspon, Kara L

    2015-10-01

    Trait absorption reflects a propensity to have one's attention drawn to engaging sensory or imaginal experiences. It is related to self-reported levels of positive and negative emotionality, but little work has examined whether absorption is related to greater levels of basic emotional processing. We used the late positive potential (LPP) to pictures and P3 response to subsequent startle probes during those pictures to examine how absorption was related to initial emotional processing and reactivity to a second stimulus. Across genders, absorption was positively related to LPP amplitude to emotional versus neutral pictures at PZ, and it was negatively related to overall P3 amplitude to startle probes at FZ. Thus, absorption appears to index greater processing of emotional material at the cost of reduced processing of subsequent incoming stimuli.

  9. APPLICATION OF ABSORPTION SPECTROSCOPY TO ACTINIDE PROCESS ANALYSIS AND MONITORING

    SciTech Connect

    Lascola, R.; Sharma, V.

    2010-06-03

    The characteristic strong colors of aqueous actinide solutions form the basis of analytical techniques for actinides based on absorption spectroscopy. Colorimetric measurements of samples from processing activities have been used for at least half a century. This seemingly mature technology has been recently revitalized by developments in chemometric data analysis. Where reliable measurements could formerly only be obtained under well-defined conditions, modern methods are robust with respect to variations in acidity, concentration of complexants and spectral interferents, and temperature. This paper describes two examples of the use of process absorption spectroscopy for Pu analysis at the Savannah River Site, in Aiken, SC. In one example, custom optical filters allow accurate colorimetric measurements of Pu in a stream with rapid nitric acid variation. The second example demonstrates simultaneous measurement of Pu and U by chemometric treatment of absorption spectra. The paper concludes with a description of the use of these analyzers to supplement existing technologies in nuclear materials monitoring in processing, reprocessing, and storage facilities.

  10. 76 FR 44049 - Guidance for Fuel Cycle Facility Change Processes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... COMMISSION Guidance for Fuel Cycle Facility Change Processes AGENCY: Nuclear Regulatory Commission. ACTION... for Fuel Cycle Facility Change Processes'' in the Federal Register for a 30 day public comment period.... DG-3037 describes the types of changes for fuel cycle facilities for which licensees are to...

  11. Optimization of a solar powered absorption cycle under Abu Dhabi's weather conditions

    SciTech Connect

    Al-Alili, A.; Hwang, Y.; Radermacher, R.; Kubo, I.

    2010-12-15

    In order for the solar absorption air conditioners to become a real alternative to the conventional vapour compression systems, their performance has to be improved and their total cost has to be reduced. A solar powered absorption cycle is modeled using the Transient System Simulation (TRNSYS) program and Typical Meteorological Year 2 data of Abu Dhabi. It uses evacuated tube collectors to drive a 10 kW ammonia-water absorption chiller. Firstly, the system performance and its total cost are optimized separately using single objective optimization algorithms. The design variables considered are: the collector slope, the collector mass flow rate, the collector area and the storage tank volume. The single objective optimization results show that MATLAB global optimization methods agree with the TRNSYS optimizer. Secondly, MATLAB is used to solve a multi-objective optimization problem to improve the system's performance and cost, simultaneously. The optimum designs are presented using Pareto curve and show the potential improvements of the baseline system. (author)

  12. Supercontinuum based absorption spectrometer for cycle-resolved multiparameter measurements in a rapid compression machine.

    PubMed

    Werblinski, Thomas; Kleindienst, Stefan; Engelbrecht, Rainer; Zigan, Lars; Will, Stefan

    2016-06-10

    A broadband supercontinuum (SC) based absorption spectrometer capable of cycle-resolved multiparameter measurements at internal combustion (IC) engine conditions is presented. Three parameters, temperature, pressure and water mole fraction, were extracted from broadband near-infrared H2O absorption spectra, spanning the wavelength-range from 1340 to 1405.5 nm, which exhibits a large number of specific H2O transitions. The spectrometer is based on spatial domain detection and features a near-infrared line scan camera as a detector. Measurements were performed during a compression cycle of a rapid compression machine comprising a pressure and temperature range from 2.5 to 65 bar and 300 to 900 K, respectively. With the new spectrometer, we are for the first time, based on the authors' knowledge, able to perform measurements based on SC radiation over a complete compression and expansion stroke at measurement rates up to 50 kHz. A detailed overview is provided about the best match algorithm between theory and experiments, including parameters from two different spectral databases, namely the Barber-Tennyson database (BT2) and HITRAN2012. The results indicate that spectral broadening effects are not properly described by theory, especially at pressure levels exceeding 20 bar, which culminates in a clear underestimation of the derived pressure data by SC absorption spectroscopy. Nevertheless, temperature can be determined accurately by performing a three-parameter fit based on water mole fraction, temperature, and pressure. In contrast, making use of pressure transducer data as look-up values and varying only temperature and H2O mole fraction to find the best match leads to a clear overestimation of temperature at elevated pressures.

  13. Absorption process for producing oxygen and nitrogen and solution therefor

    DOEpatents

    Roman, Ian C.; Baker, Richard W.

    1990-09-25

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible.

  14. Absorption process for producing oxygen and nitrogen and solution therefor

    DOEpatents

    Roman, Ian C.

    1984-01-01

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible.

  15. Absorption process for producing oxygen and nitrogen and solution therefor

    DOEpatents

    Roman, I.C.; Baker, R.W.

    1990-09-25

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible. 1 figure

  16. Integrated reactive absorption process for synthesis of fatty esters.

    PubMed

    Kiss, Anton Alexandru; Bildea, Costin Sorin

    2011-01-01

    Reactive separations using green catalysts offer great opportunities for manufacturing fatty esters, involved in specialty chemicals and biodiesel production. Integrating reaction and separation into one unit provides key benefits such as: simplified operation, no waste, reduced capital investment and low operating costs. This work presents a novel heat-integrated reactive absorption process that eliminates all conventional catalyst related operations, efficiently uses the raw materials and equipment, and considerably reduces the energy requirements for biodiesel production--85% lower as compared to the base case. Rigorous simulations based on experimental results were carried out using Aspen Plus and Dynamics. Despite the high degree of integration, the process is well controllable using an efficient control structure proposed in this work. The main results are provided for a plant producing 10 ktpy fatty acid methyl esters from methanol and waste vegetable oil with high free fatty acids content, using sulfated zirconia as solid acid catalyst.

  17. Interest of absorption spectroscopy for the control of industrial processes. Application to H2 massive production

    NASA Astrophysics Data System (ADS)

    Croizé, L.; Doizi, D.; Larousse, B.; Pailloux, A.; Reaux, D.; Gallou, C.; Dauvois, V.; Roujou, J. L.; Zanella, Y.; Carles, P.

    2010-08-01

    Absorption and TDLA spectroscopies find their applications in a lot of fields of research. The purpose of this article is to show how these methods can bring significant advances in chemical research projects. “H2 massive production” using nuclear heat together with a thermochemical cycle is an important way to massively produce hydrogen, a potential energy vector. The sulfur-iodine cycle and the hybrid copper-chloride thermochemical cycles are some good candidates for water splitting. In the case of the sulfur-iodine thermochemical cycle, the overall efficiency of the process essentially depends on the efficiency of HI section. Using optical techniques, such as a FTIR spectrometer for H2O and HI concentrations determination, and a TDL spectrometer for I2 measurements, it enables to get very significant results that will be useful to build a new thermodynamic model of the HI separation. This nonintrusive method has avoided any vapor change and prevented tedious experiments in harsh environments. The same methodology is now applied for the study of the hydrolysis reaction of the thermochemical hybrid copper-chloride cycle. The study of this reaction is very important to assess the viability of this cycle because this reaction is not thermodynamically favored and it only occurs if a large excess of water is used. To better understand the influence of various parameters, such as water stoichiometry, temperature, reaction duration, an experimental setup has been designed and realized. The experimental setup uses two spectrometers to study the speciation of the gaseous phase and optimize the kinetics of the hydrolysis reaction. Concentrations of HCl and H2O are obtained by fitting experimental FTIR spectra with calculated spectra. Parasitic reactions can appear leading to formation of Cl2, measured by UV-Visible spectrophotometry. The high temperature reaction at around 530°C is the only reaction of this copper-chloride cycle which is thermodynamically favored. A

  18. Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigeration for lesser developed countries

    NASA Astrophysics Data System (ADS)

    Erickson, Donald C.

    1990-02-01

    The Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigerator is a solar thermal technology which provides low cost, efficient, reliable ice-making to areas without ready access to electricity. An ISAAC refrigeration system consists of a compound parabolic solar collector, two pressure vessels, a condenser, a cold box or refrigerated space, and simple connective piping -- no moving parts or electrical components. Most parts are simple construction or plumbing grade materials, locally available in many remote areas. This technology has numerous potential benefits in lesser developed countries both by providing a cheap, reliable source of ice, and, since manufacture requires only semi-skilled labor, a source of employment to the local economy. Applications include vaccine storage for health care clinics; fish, meat, and dairy product storage; and personal consumption. Importantly, this technology increases the quality of life for people in lesser developed countries without depleting fossil fuel resources or increasing the release of greenhouse gases such as CO2 and chlorofluorocarbons.

  19. Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigeration for lesser developed countries

    SciTech Connect

    Erickson, D.C.

    1990-02-06

    The Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigerator is a solar thermal technology which provides low cost, efficient, reliable ice-making to areas without ready access to electricity. An ISAAC refrigeration system consists of a compound parabolic solar collector, two pressure vessels, a condenser, a cold box or refrigerated space, and simple connective piping -- no moving parts or electrical components. Most parts are simple construction or plumbing grade materials, locally available in many remote areas. This technology has numerous potential benefits in lesser developed countries both by providing a cheap, reliable source of ice, and, since manufacture requires only semi-skilled labor, a source of employment to the local economy. Applications include vaccine storage for health care clinics; fish, meat, and dairy product storage; and personal consumption. Importantly, this technology increases the quality of life for people in lesser developed countries without depleting fossil fuel resources or increasing the release of greenhouse gases such as CO{sub 2} and chlorofluorocarbons.

  20. Modelling the absorption refrigeration cycle using partially miscible working fluids by group contribution methods

    NASA Astrophysics Data System (ADS)

    Larkeche, O.; Meniai, A.-H.; Cachot, T.

    2012-06-01

    The present study concerns the cycle performance modelling of a particular configuration of an absorption refrigeration machine based on phase separation as well as development of a strategy for computer aided design of absorbents. The model uses predictive methods based on the group contribution concept for the computation of the thermodynamic phase equilibria involved such as liquid-liquid and vapour-liquid as well as enthalpy-concentration diagrams. The proposed absorbents computer-aided design strategy is based on the exploration of a number of structural group combinations obtained from a selected set of functional groups, according to the chemistry laws. The model was tested on four different absorbent-refrigerant pairs reported in the literature, namely (benzyl ethyl amine-glycerol), (water-hexanoic acid), (water-2-hexanone) and (water-ethyl propionate) as well as on pairs where the absorbent compound is generated by the proposed absorbent design strategy and the refrigerant is water. The results show that quite good values of the coefficient of performance (COP) can be obtained, indicating that this cycle configuration is promising and energetically efficient, mainly due to hardware savings, i.e. absence of condenser. However, other working fluid combinations have to be tested using the proposed model.

  1. Effect of soaking and single/two cycle high pressure treatment on water absorption, color, morphology and cooked texture of brown rice.

    PubMed

    Yu, Yong; Pan, Fang; Ramaswamy, H S; Zhu, Songming; Yu, Liang; Zhang, Qiuting

    2017-05-01

    Water absorption, color, morphology and cooked texture of brown rice were evaluated after selected soaking (30-50 °C, 30 min) and high pressure treatment (HPT) (100-500 MPa; single or two cycle; total holding time 10 min). Water absorption ratio and lightness values of brown rice were increased by soaking and HPT. Hardness and gumminess values of cooked brown rice were reduced while springiness and cohesiveness were elevated by HPT. Scanning electron microscopy indicated that HPT improved the texture of brown rice by disrupting the structure of rice bran layer, which allowed easier water penetration into the rice grain during cooking. Moreover, the two cycle HPT resulted in lighter color and softer texture for cooked brown rice than single cycle HPT primarily caused by the more severe structural disruption of bran layer. Overall, two cycle HPT after soaking could potentially improve the quality of brown rice, taking about the same time as the single cycle HPT. Further, the quality improvements with the two cycle HPT were facilitated at lower pressure levels thereby providing better commercial processing opportunities.

  2. Combined heat and mass transfer in absorption processes

    SciTech Connect

    Grossman, G.

    1982-01-01

    The approach to theoretical analysis of the combined heat and mass transfer process taking place in absorption systems is described. The two tranfer phenomena are strongly coupled here. The purpose of the analysis is to relate, quantitatively, the heat and mass transfer coefficients to the physical properties of the working fluids and to the geometry of the system. The preferred configuration is that of a falling film of liquid on a metallic surface which serves to transfer heat from the absorbent in contact with the vapor of the absorbate. The model developed may be solved for laminar, turbulent, or transition flow regimes. The results of the solution describe the development of the thermal and concentration boundary layers and the variation of the temperatures, concentrations, and heat and mass fluxes. These quantities in their normalized, dimensionless form depend on two characteristic parameters of the system: the Lewis number Le and the dimensionless heat of absorption lambda. The length in the direction of flow is normalized with respect to the Peclet number and the film thickness. Heat and mass transfer coefficients for the system were calculated. The Sherwood number for mass transfer from the vapor-liquid interface to the bulk of the film reaches a constant value of 3.63 with fully developed boundary layers for both the adiabatic and constant temperature wall. The Nusselt number for heat transfer from the interface to the bulk reaches under the same conditions values of 3.63 and 2.67 for the adiabatic and constant temperature wall, respectively. The Nusselt number for heat tranfer from the bulk to the wall reaches 1.60.

  3. Sedimentary processes and crustal cycling on Venus

    NASA Technical Reports Server (NTRS)

    Warner, J. L.

    1983-01-01

    Sediment exists on the Venus surface. It is observed in Venera images between outcrops and boulders of sedimentary rocks. Sediment is produced by pyroclastic volcanism and chemical weathering. Chemical weathering is driven by an enhanced activity of water and an elevated surface temperature. Sediment is transported by wind action and lithified by cementration and diagenesis. Cementation may be by carbonate or silica cement; diagenesis may be products of chemical weathering acting as cement, or by compaction and recrystallization of sediment into a texture with interlocking grains. Sediment may be transported from the top of sialic continents (such as Ishtar) to the modal plains where it is deposited, lithified, and integrated into thy local crust. As new layers are added, the bottom of the crust melts and is, in part, returned to the mantle. A steady-state chemical exchange might exist by this mechanism of crustal cycling that links atmosphere, continents, modal plains, and mantle.

  4. Fuel processing and thermochemical/photochemical cycles

    NASA Astrophysics Data System (ADS)

    Hunt, Arlon J.

    A long sought goal of energy research has been to find a method to produce hydrogen fuel economically by splitting water using sunlight as the source of energy. Implementing method of producing useful fuels from raw materials using sunlight on a large scale generally involves significant capital and energy costs. Sunlight is an attractive means of providing a renewable source of energy to drive the process after providing the initial capital outlay. However, the combination of capital costs to provide concentrated solar energy and the elaborate and expensive plants required to carry out the chemical processes puts a heavy financial burden on this approach to a clean and renewable energy economy. Solar driven fuel processing methods include thermal decomposition, thermochemical, photochemical, electrochemical, biochemical, and hybrid reactions. The range of approaches to carry out these processes runs the gamut from well established chemical engineering practices with near term predictable costs, to long term basic photochemical processes, the details of which are still speculative.

  5. Transforming revenue cycle processes in an indigent care setting.

    PubMed

    Drake, Jeff; Kane, Cheri

    2009-09-01

    Steps that Grady Health System in Atlanta undertook in transforming its revenue cycle include: Conducting a complete revenue cycle assessment. Enhancing staff skill levels and customer service techniques--and holding staff. accountable for errors. Automating processes that previously were performed manually. Validating applications for financial assistance electronically. Screening for Medicare/Medicaid eligibility among self-pays.

  6. Available solar exergy in an absorption cooling process

    SciTech Connect

    Millan, M.I.; Martin, E.; Hernandez, F.

    1996-06-01

    Using the global solar radiation on a flat plate converter of selective surface, the process temperature, the ambient temperature and the characteristics of the collector as initial data; the maximum available exergy for feeding a lithium bromide absorption cooling machine and its daily distribution in Madrid is determined. The conversion of solar radiation into exergy is calculated through the Mueser endoreversible engine. The model, which takes into account the relative Sun-Earth movements, the presence of the atmosphere, the transitory regime, the losses to the surroundings and the losses caused by the heat capacities effect, allows a maximum hourly exergy efficiency of the available heat between 11 and 14.6% and a daily exergy efficiency in the order of 3% to be obtained. The maximum available daily exergy varies from 800 kJ/(m{sup 2} day) for a very hot clear day to 950 kJ/(m{sup 2} day) for a warm clear day. 11 refs., 2 figs., 4 tabs.

  7. Developments in absorptive glass mat separators for cycling applications and 36 V lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Toniazzo, V.; Lambert, U.

    The major markets for valve-regulated lead-acid (VRLA) batteries are undergoing a radical upheaval. In particular, the telecommunications industry requires more reliable power supplies, and the familiar 12 V electrical system in cars will probably be soon replaced by a 36/42 V system, or by other electrical systems if part of the automotive market is taken over by hybrid electrical vehicles (HEVs). In order to meet these new challenges and enable VRLA batteries to provide a satisfactory life in float and cycling applications in the telecommunication field, or in the high-rate-partial-state-of-charge service required by both 36/42 V automobiles and HEVs, the lead-acid battery industry has to improve substantially the quality of present VRLA batteries based on absorptive glass mat (AGM) technology. Therefore, manufacturing steps and cell components have to be optimized, especially AGM separators as these are key components for better production yields and battery performance. This paper shows how the optimal segregation of the coarse and fine fibres in an AGM separator structure can improve greatly the properties of the material. The superior capillarity, springiness and mechanical properties of the 100% glass Amerglass multilayer separator compared with commercial monolayer counterparts with the same specific surface-area is highlighted.

  8. Life cycle costs for chemical process pumps

    SciTech Connect

    Urwin, B.; Blong, R.; Jamieson, C.; Erickson, B.

    1998-01-01

    Though construction and startup costs are always a concern, proper investment in equipment and installation will save money down the line. This is particularly important for heavily used items, such as centrifugal pumps, one of the workhouses of the chemical process industries (CPI). By properly sizing and installing a centrifugal pump, the life and efficiency of the pump can be increased. At the same time, maintenance costs can be reduced. When considering a new pump, there are several areas that require attention. The first is the baseplate design. The impeller is another area of concern. The seal chamber, the third area of importance, must be designed for proper heat dissipation and lubrication of seal faces. Lastly, the power end must be considered. Optimum bearing life, effective oil cooling and minimum shaft deflection are all vital. The paper discusses installation costs, operating cost, maintenance cost, seal environment, and extended bearing life.

  9. Development and Evaluation of a Novel Integrated Vacuum Carbonate Absorption Process

    SciTech Connect

    Lu, Yongqi; Rostam-Abadi, Massoud; Ye, Xinhuai; Zhang, Shihan; Ruhter, David; Khodayari, Arezoo; Rood, Mark

    2012-04-30

    This project was aimed at obtaining process engineering and scale-up data at a laboratory scale to investigate the technical and economic feasibility of a patented post-combustion carbon dioxide (CO{sub 2}) capture process?the Integrated Vacuum Carbonate Absorption Process (IVCAP). Unique features of the IVCAP include its ability to be fully-integrated with the power plant?s steam cycle and potential for combined sulfur dioxide (SO{sub 2}) removal and CO{sub 2} capture. Theoretical and experimental studies of this project were aimed at answering three major technical questions: 1) What additives can effectively reduce the water vapor saturation pressure and energy requirement for water vaporization in the vacuum stripper of the IVCAP? 2) What catalysts can promote CO{sub 2} absorption into the potassium carbonate (PC) solution to achieve an overall absorption rate comparable to monoethanolamine (MEA) and are the catalysts stable at the IVCAP conditions and in the flue gas environment? 3) Are any process modifications needed to combine SO{sub 2} and CO{sub 2} removal in the IVCAP? Lab-scale experiments and thermodynamic and process simulation studies performed to obtain detailed information pertinent to the above three technical questions produced the following results: 1) Two additives were identified that lower the saturation pressure of water vapor over the PC solution by about 20%. 2) The carbonic anhydrase (CA) enzyme was identified as the most effective catalyst for promoting CO{sub 2} absorption. The absorption rate into the CO{sub 2}-lean PC solution promoted with 300 mg/L CA was several times slower than the corresponding 5 M MEA solution, but absorption into the CO{sub 2}-rich PC solution was comparable to the CO{sub 2}-rich MEA solution. The tested CA enzymes demonstrated excellent resistance to major flue gas impurities. A technical-grade CA enzyme was stable at 40{degrees}C (104{degrees}F) over a six-month test period, while its half-life was about two

  10. 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.

  11. Probing the Sub-cycle AC Stark Shift by means of Attosecond Pulses: An ab initio Study of Transient Absorption

    NASA Astrophysics Data System (ADS)

    Zhao, Di; Telnov, Dmitry A.; Chu, Shih-I.

    2012-06-01

    We report a first fully ab initio theoretical exploration of the sub-cycle dynamical AC Stark shift and broadening of He atoms driven by an attosecond pulse and IR pulse. Since the duration of the UV pulse is much shorter than that of the optical cycle of the IR dressing laser field, the sub-cycle dynamics of the dressed atoms can be unfolded by applying the attosecond pulse at different time delay. A nonperturbative method is developed to calculate the transient absorption spectrum without weak-field limitation. By solving the time-dependent Schr"odinger equation accurately by means of the time-dependent generalized pseudospectral method, we predict novel sub-cycle laser-induced time-dependent AC Stark shift and power broadening of He atoms whose dynamical features are in good agreement with the latest ongoing experiments at UCF. Detailed results will be presented. This work is partially supported by DOE and NSF.

  12. Enrichment process of biogas using simultaneous Absorption - Adsorption methods

    NASA Astrophysics Data System (ADS)

    Kusrini, Eny; Lukita, Maya; Gozan, Misri; Susanto, Bambang Heru; Nasution, Dedy Alharis; Rahman, Arif; Gunawan, Cindy

    2017-03-01

    Removal of CO2 in biogas is an essential methods to the purification and upgrading of biogas. Natural Clinoptilolite zeolites were evaluated as sorbents for purification of biogas that produced from palm oil mill effluent (POME) by anerobic-digestion method. The absorption and adsorption experiments were conducted in a fixed-bed two column adsorption unit by simultaneous absorption-adsorption method. The Ca(OH)2 solution with concentration of 0.062 M was used as absorption method. Sorbent for removal of CO2 in biogas have been prepared by modifying of Clinoptilolite zeolites with an acid (HCl, 2M) and alkaline (NaOH, 2M), calcined at 450°C and then coated using chitosan (0.5 w/v%) in order to increase their adsorption capacity. The removal of CO2 in biogas was achieved about ˜83% using 2.5 g of sorbent zeolite (2M)/chitosan dosage for each column, breakthrough time of 30 min, and flow rate of 100 mL/min. Clinoptilolite zeolites with modifications of an acid-alkaline and chitosan (zeolite (2M)/chitosan) are promising sorbents due to the amine groups from chitosan and high surface-volume ratio are one of important factors in a simultaneous absorption-adsorption method.

  13. Development and proof-testing of advanced absorption refrigeration cycle concepts. Report on Phases 1 and 1A

    SciTech Connect

    Modahl, R.J.; Hayes, F.C.

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  14. The TMIS life-cycle process document, revision A

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Technical and Management Information System (TMIS) Life-Cycle Process Document describes the processes that shall be followed in the definition, design, development, test, deployment, and operation of all TMIS products and data base applications. This document is a roll out of TMIS Standards Document (SSP 30546). The purpose of this document is to define the life cycle methodology that the developers of all products and data base applications and any subsequent modifications shall follow. Included in this methodology are descriptions of the tasks, deliverables, reviews, and approvals that are required before a product or data base application is accepted in the TMIS environment.

  15. Method for processing seismic data to identify anomalous absorption zones

    DOEpatents

    Taner, M. Turhan

    2006-01-03

    A method is disclosed for identifying zones anomalously absorptive of seismic energy. The method includes jointly time-frequency decomposing seismic traces, low frequency bandpass filtering the decomposed traces to determine a general trend of mean frequency and bandwidth of the seismic traces, and high frequency bandpass filtering the decomposed traces to determine local variations in the mean frequency and bandwidth of the seismic traces. Anomalous zones are determined where there is difference between the general trend and the local variations.

  16. Reducing Design Cycle Time and Cost Through Process Resequencing

    NASA Technical Reports Server (NTRS)

    Rogers, James L.

    2004-01-01

    In today's competitive environment, companies are under enormous pressure to reduce the time and cost of their design cycle. One method for reducing both time and cost is to develop an understanding of the flow of the design processes and the effects of the iterative subcycles that are found in complex design projects. Once these aspects are understood, the design manager can make decisions that take advantage of decomposition, concurrent engineering, and parallel processing techniques to reduce the total time and the total cost of the design cycle. One software tool that can aid in this decision-making process is the Design Manager's Aid for Intelligent Decomposition (DeMAID). The DeMAID software minimizes the feedback couplings that create iterative subcycles, groups processes into iterative subcycles, and decomposes the subcycles into a hierarchical structure. The real benefits of producing the best design in the least time and at a minimum cost are obtained from sequencing the processes in the subcycles.

  17. Equatorial ionospheric absorption during half a solar cycle /1964-1970/

    NASA Technical Reports Server (NTRS)

    Gnanalingam, S.

    1974-01-01

    An extensive series of vertical incidence absorption measurements made at an equatorial station is analyzed in detail to provide information which will lead to a better understanding of the lower ionosphere. A quantitative empirical relationship is derived between absorption and 1-8 A solar flux for moderate levels of solar activity. It is shown that the threshold flux for D-region modification, at a solar zenith angle of 10 deg, is approximately 0.0005 erg per sq cm per sec. Attention is drawn to the incidence of days of high absorption even in the absence of solar X-ray activity. Available evidence points to variability of the order of 10-40 per cent in the intensity of the solar Lyman-alpha radiation as the most likely cause of these unusual, though infrequent, enhancements in absorption.

  18. Equatorial ionospheric absorption during half a solar cycle (1964-1970)

    NASA Technical Reports Server (NTRS)

    Gnanalingam, S.

    1972-01-01

    An extensive series of vertical incidence absorption measurements made at an equatorial station is analyzed in detail for a better understanding of the lower ionosphere. A quantitive empirical relationship is derived between absorption and 1 to 8 A solar flux for moderate levels of solar activity. It is shown that the threshold flux for D region modification, at a solar zenith angle of 10 deg, is approximately 0.0005 erg/sq/cm/sec. Attention is drawn to the incidence of days of high absorption even in the absence of solar X-ray activity. Available evidence points to variability of the order of 10 to 40% in the intensity of the solar Lyman alpha radiation as the most likely cause of these unusual, though infrequent, enhancements in absorption.

  19. Role of pyro-chemical processes in advanced fuel cycles

    NASA Astrophysics Data System (ADS)

    Nawada, Hosadu Parameswara; Fukuda, Kosaku

    2005-02-01

    Partitioning and Transmutation (P&T) of Minor Actinides (MAs) and Long-Lived Fission Products (LLFP) arising out of the back-end of the fuel cycle would be one of the key-steps in any future sustainable nuclear fuel cycle. Pyro-chemical separation methods would form a critical stage of P&T by recovering long-lived elements and thus reducing the environmental impact by the back-end of the fuel-cycle. This paper attempts to overview global developments of pyro-chemical process that are envisaged in advanced nuclear fuel cycles. Research and development needs for molten-salt electro-refining as well as molten salt extraction process that are foreseen as partitioning methods for spent nuclear fuels such as oxide, metal and nitride fuels from thermal or fast reactors; high level liquid waste from back-end fuel cycle as well as targets from sub-critical Accelerator Driven Sub-critical reactors would be addressed. The role of high temperature thermodynamic data of minor actinides in defining efficiency of recovery or separation of minor actinides from other fission products such as lanthanides will also be illustrated. In addition, the necessity for determination of accurate high temperature thermodynamic data of minor actinides would be discussed.

  20. Coherent Magneto-Caloric Effect Heat Engine Process Cycle

    NASA Astrophysics Data System (ADS)

    Keefe, Peter D.

    2002-11-01

    Presented is a thermodynamic argument that it is theoretically possible to cyclically process a particle of Type I superconductor in H-T space so that all heat extracted from the high temperature heat reservoir is converted into work, no heat being rejected to a low temperature heat reservoir. Importantly, a heat engine designed to operate according to this cycle would be able to continually convert the ambient heat of its surroundings into work. The author's U.S. Patent 4,638,194 sets forth the structural and methodological considerations for carrying out the cycle in the form of a heat engine.

  1. Sub-10 ns single-shot dynamic recording in holographic polymeric medium by nonlinear absorption using excited state absorption process

    NASA Astrophysics Data System (ADS)

    Kamada, Kenji; Satoh, Kazuyuki; Tanaka, Yoshito

    2016-09-01

    Optical recording by a single shot of an 8 ns laser pulse in a dye-doped holographic polymeric medium was demonstrated with a peak power as low as 71 W at a wavelength of 402 nm. Nonlinear absorption triggered by two-photon absorption and enhanced by the succeeding process allows high-speed recording corresponding to 125 Mbps (3.4 times the recording speed of a Blu-ray Disc). The preformed holographic grating in the medium enhanced the readout signal through diffraction, resulting in a signal-to-noise ratio of about 15 dB. The recording capacity was estimated at ca. 80 GB/side for 100 µm/side by recording 20 layers, but that of over TB/side class would be possible for optical optimization. Theoretically, it can be improved to 10 TB/side for 800 µm/side by recording 400 layers.

  2. Advancement of Double Effect Absorption Cycle by Input of Low Temperature Waste Heat

    NASA Astrophysics Data System (ADS)

    Kojima, Hiroshi; Edera, Masaru; Nakamura, Makoto; Oka, Masahiro; Akisawa, Atsushi; Kashiwagi, Takao

    Energy conservation is becoming important for global environmental protection. New simple techniques of more efficient1y using the waste heat of gas co-generation systems for refrigerationare required. In first report, a new method of using the low temperature waste heat for refrigeration was proposed, and the basic characteristics of the promising methods of recovering waste heat were c1arified. In this report, the more detailed simulation model of the series flow type double effect absorption refrigerator with auxiliary heat exchanger was constructed and the static characteristics were investigated. Then experiments on this advanced absorption refrigerator were carried out, and the results of the calculation and experiments were compared and discussed. Moreover, the betterment of the simulation model of this advanced absorption refrigerator was carried out.

  3. Incorporating Terrestrial Processes in Models of PETM Carbon Cycle Evolution

    NASA Astrophysics Data System (ADS)

    Bowen, G. J.

    2016-12-01

    Evidence for the massive, rapid release of carbon to the ocean/atmosphere/biosphere system at the onset of the PETM is unequivocal, but the sequence of feedbacks that governed the evolution and recovery of the carbon cycle over the subsequent 150,000 years of the event remain unclear. Sedimentological evidence suggests that much of the excess carbon was eventually sequestered as carbonate in marine sediments, but there is also significant and growing evidence for changes in continental carbon cycle processes, most of which have not been incorporated in models of the event. I describe several aspects of the observed or implied continental response to the PETM, including changes in ecosystem organic carbon storage, soil carbonate growth, and export of organic carbon to the marine margins. These processes, along with continental silicate weathering, have been incorporated in a terrestrial module for a simple box model of the PETM carbon cycle, which is being used to evaluate their potential impact on global carbon cycle response and recovery. Although changes in terrestrial organic carbon storage can help explain patterns of global carbon isotope change throughout the event, constraints from ocean pH records suggest that other mechanisms must have contributed to pacing the duration and recovery of the PETM. Model results suggest that enhanced soil carbonate formation and the provenance of organic carbon buried in continental margin sediments are two poorly constrained variables that could alter the interpretation and implications of the continental records. Given the strong potential for, and high uncertainty in, future changes in terrestrial carbon cycle processes, resolving the nature and long-term impacts of such changes during the PETM represents a major opportunity to leverage the geologic record of this hyperthermal to increase understanding of human-induced global change.

  4. Study on High Efficient Absorption Refrigerator Using Multi-effect Cycle

    NASA Astrophysics Data System (ADS)

    Inoue, Naoyuki; Irie, Tomoyoshi; Saito, Kiyoshi; Kawai, Sunao

    Double effect chillers are commonly used as cooling machines for air condition. Great efforts have been making to improve the efficiency for a long time, and now the COP is very near to the limitation of double effect cycles. Triple effect cycles are expected for the next step beyond double effect cycles, but have some problems of high temperature and high pressure in the high stage generator. High temperature of absorbent causes corrosion problem and high vapor pressure over atmospheric pressure causes the restriction of legal regulation. This paper deals with many types of triple effect cycles. The temperature and dew point of the high stage generator are analyzed, several types are selected for low dew point, and one of them is more analyzed in detail.

  5. Laser absorption spectroscopy system for vaporization process characterization and control

    SciTech Connect

    Galkowski, J.; Hagans, K.

    1993-09-07

    In support of the Lawrence Livermore National Laboratory`s (LLNL`s) Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program, a laser atomic absorption spectroscopy (LAS) system has been developed. This multi-laser system is capable of simultaneously measuring the line densities of {sup 238}U ground and metastable states, {sup 235}U ground and metastable states, iron, and ions at up to nine locations within the separator vessel. Supporting enrichment experiments that last over one hundred hours, this laser spectroscopy system is employed to diagnose and optimize separator system performance, control the electron beam vaporizer and metal feed systems, and provide physics data for the validation of computer models. As a tool for spectroscopic research, vapor plume characterization, vapor deposition monitoring, and vaporizer development, LLNL`s LAS laboratory with its six argon-ion-pumped ring dye lasers and recently added Ti:Sapphire and external-cavity diode-lasers has capabilities far beyond the requirements of its primary mission.

  6. Characterization of the relationship of the cure cycle chemistry to cure cycle processing properties

    NASA Technical Reports Server (NTRS)

    Kranbuehl, D. E.

    1986-01-01

    Dynamic Dielectric measurements made over a wide range of frequency provide a sensitive and convenient means for monitoring the cure process in thermosets and thermoplastics. The measurement of dielectric relaxation is one of only a few instrumental techniques available for studying molecular properties in both the liquid and solid states. Furthermore, it is probably the only convenient experimental technique for studying the polymerization process of going from a monomeric liquid of varying viscosity to a crosslinked, insoluble, high temperature solid. The objective of the research is to develop on-line dielectric instrumentation for quantitative nondestructive material evaluation and closed loop smart cure cycle control. The key is to relate the chemistry of the cure cycle process to the dielectric properties of the polymer system by correlating the time, temperature, and frequency dependent dielectric measurements with chemical characterization measurements. Measurement of the wide variation in magnitude of the complex permittivity with both frequency and state of cure, coupled with chemical characterization work, have been shown in the laboratory to have the potential to determine: resin quality, composition and age; cure cycle window boundaries; onset of flow and point of maximum flow; extent of and completion of reaction; evolution of volatiles; T sub g; and, crosslinking and molecular weight buildup.

  7. [Absorption spectra analysis in the degradation process of quinoline in aqueous solution by VUV lights].

    PubMed

    Zhu, Da-Zhang; Sun, Dong-Mei; Wang, Shi-Long; Sun, Xiao-Yu; Ni, Ya-Ming

    2009-07-01

    The feasibility of monitoring the degradation progress on line by UV-Vis absorption spectra in the degradation process of quinoline in aqueous solution using the low-pressure quartz mercury lamp as vacuum ultraviolet source was evaluated by the monitoring and protracting of the UV-Vis absorption spectra at different time. The characteristic and mechanism of the change in the UV absorption spectra were analyzed by monitoring the concentration of the substrate, COD (chemical oxygen demand), TOC (total organic carbon) and pH value of the solution. It was showed that quinoline occurs in different forms under different pH conditions and consequently causes different UV-Vis absorption spectra due to the N atom in the pyridine ring. In the degradation progress, the UV-Vis absorption spectra were impacted by the degradation rate of the substrates, the production rate of the intermediates and the pH value of the solution. Proton acids were produced as intermediates and make quinoline occur in the form of its conjugated acid. When the increase in the absorption produced by the protonation was equal to the decrease induced by the degradation, the curve of the absorption at 313 nm, the characteristic absorption peak of quinoline, showed a flat in the duration of 1-3 min and then decayed continuously. In addition, the absorption at 254 nm reached a maximum at 5 min and then decayed continuously to nearly 0 at 30 min, when the absorption of the system only occurred in the region of wavelength shorter than 220 nm, indicating that the substrate was degraded completely. The research revealed that UV absorption spectra could be used to monitor the degradation process of quinoline in aqueous solution by VUV lights.

  8. LSA silicon material task closed-cycle process development

    NASA Technical Reports Server (NTRS)

    Roques, R. A.; Wakefield, G. F.; Blocher, J. M., Jr.; Browning, M. F.; Wilson, W.

    1979-01-01

    The initial effort on feasibility of the closed cycle process was begun with the design of the two major items of untested equipment, the silicon tetrachloride by product converter and the rotary drum reactor for deposition of silicon from trichlorosilane. The design criteria of the initial laboratory equipment included consideration of the reaction chemistry, thermodynamics, and other technical factors. Design and construction of the laboratory equipment was completed. Preliminary silicon tetrachloride conversion experiments confirmed the expected high yield of trichlorosilane, up to 98 percent of theoretical conversion. A preliminary solar-grade polysilicon cost estimate, including capital costs considered extremely conservative, of $6.91/kg supports the potential of this approach to achieve the cost goal. The closed cycle process appears to have a very likely potential to achieve LSA goals.

  9. Impact of activation process on fog life cycle

    NASA Astrophysics Data System (ADS)

    Mazoyer, Marie; Burnet, Frédéric; Lac, Christine; Roberts, Greg; Dupont, Jean-Charles; Haeffelin, Martial; Elias, Thierry

    2015-04-01

    Fogs are complex meteorological system dealing with fine scale processes. Subtle interaction between radiative, dynamic, turbulent and microphysic processes can lead to different fog life cycle, which make prediction difficult. The droplets that composed fogs are formed trough the activation of aerosol particles called CCN (cloud condensation nuclei) described by the Köhler theory (Köhler, 1936). The number and distribution of the droplets activated during fog formation is determined by the aerosols particles properties and number and the ambient vapor supersaturation of the atmosphere. In the frame of the PreViBOSS project, an in-situ measurement platform of fog properties at ground level was deployed at SIRTA (Instrumented Site for Atmospheric Remote Sensing Research) during winter 2010 to 2013. Microphysics data supply a detailed characterization of number size spectrum from dry to wet aerosols particles and inform on the abilities of the aerosols particles to act as a CCN. 48 fog events have been studied. Supersaturation critical values and concentrations of CCN have been determined and linked to aerosols properties. The main impact of aerosols size distribution on activation have been pointed out. The study of droplets spectra evolution reveals the major physical processes into fogs and suggests that even if thermodynamic dominates the fog life cycle, activation process seems to have a significant effect. Large eddy simulation of fog run with Meso-NH model allow to explore precisely the interaction between fog physical processes and to quantify activation impact. Supersaturation modelling is a key point, a new pseudo-prognostic scheme (Thouron et al., 2012) is used. Confrontation between a detailed experimental study and three-dimensional fine scale simulation in LES provides an accurate investigation of the impact of activation process on fog life cycle.

  10. A Preliminary Study on Designing and Testing of an Absorption Refrigeration Cycle Powered by Exhaust Gas of Combustion Engine

    NASA Astrophysics Data System (ADS)

    Napitupulu, F. H.; Daulay, F. A.; Dedy, P. M.; Denis; Jecson

    2017-03-01

    In order to recover the waste heat from the exhaust gas of a combustion engine, an adsorption refrigeration cycle is proposed. This is a preliminary study on design and testing of a prototype of absorption refrigeration cycle powered by an internal combustion engine. The heat source of the cycle is a compression ignition engine which generates 122.36 W of heat in generator of the cycle. The pairs of absorbent and refrigerant are water and ammonia. Here the generator is made of a shell and tube heat exchanger with number of tube and its length are 20 and 0.69 m, respectively. In the experiments the exhaust gas, with a mass flow rate of 0.00016 kg/s, enters the generator at 110°C and leaves it at 72°C. Here, the solution is heated from 30°C to 90°C. In the evaporator, the lowest temperature can be reached is 17.9°C and COP of the system is 0.45. The main conclusion can be drawn here is that the proposed system can be used to recycle the waste heat and produced cooling. However, the COP is still low.

  11. Fractional kinetics in drug absorption and disposition processes.

    PubMed

    Dokoumetzidis, Aristides; Macheras, Panos

    2009-04-01

    We explore the use of fractional order differential equations for the analysis of datasets of various drug processes that present anomalous kinetics, i.e. kinetics that are non-exponential and are typically described by power-laws. A fractional differential equation corresponds to a differential equation with a derivative of fractional order. The fractional equivalents of the "zero-" and "first-order" processes are derived. The fractional zero-order process is a power-law while the fractional first-order process is a Mittag-Leffler function. The latter behaves as a stretched exponential for early times and as a power-law for later times. Applications of these two basic results for drug dissolution/release and drug disposition are presented. The fractional model of dissolution is fitted successfully to datasets taken from literature of in vivo dissolution curves. Also, the proposed pharmacokinetic model is fitted to a dataset which exhibits power-law terminal phase. The Mittag-Leffler function describes well the data for small and large time scales and presents an advantage over empirical power-laws which go to infinity as time approaches zero. The proposed approach is compared conceptually with fractal kinetics, an alternative approach to describe datasets with non exponential kinetics. Fractional kinetics offers an elegant description of anomalous kinetics, with a valid scientific basis, since it has already been applied in problems of diffusion in other fields, and describes well the data.

  12. Quantum thermodynamic processes: a control theory for machine cycles

    NASA Astrophysics Data System (ADS)

    Birjukov, J.; Jahnke, T.; Mahler, G.

    2008-07-01

    The minimal set of thermodynamic control parameters consists of a statistical (thermal) and a mechanical one. These suffice to introduce all the pertinent thermodynamic variables; thermodynamic processes can then be defined as paths on this 2-dimensional control plane. Putting aside coherence we show that for a large class of quantum objects with discrete spectra and for the cycles considered the Carnot efficiency applies as a universal upper bound. In the dynamic (finite time) regime renormalized thermodynamic variables allow to include non-equilibrium phenomena in a systematic way. The machine function ceases to exist in the large speed limit; the way, in which this limit is reached, depends on the type of cycle considered.

  13. Processes linking the hydrological cycle and the atmospheric radiative budget

    NASA Astrophysics Data System (ADS)

    Fueglistaler, Stephan; Dinh, Tra

    2016-04-01

    We study the response of the strength of the global hydrological cycle to changes in carbon dioxide (CO2) using the HiRAM General Circulation Model developed at the Geophysical Fluid Dynamics Laboratory (GFDL), with the objective to better connect the well-known energetic constraints to physical processes. We find that idealized model setups using a global slab ocean and annual mean insolation give similar scalings as coupled atmosphere-ocean models with realistic land and topography. Using the surface temperatures from the slab ocean runs, we analyse the response in the atmospheric state and hydrological cycle separately for a change in CO2 (but fixed surface temperature), and for a change in surface temperature (but fixed CO2). The former perturbation is also referred to as the "fast" response, whereas the latter is commonly used to diagnose a model's climate sensitivity. As expected from the perspective of the atmospheric radiative budget, an increase in CO2 at fixed surface temperature decreases the strength of the hydrological cycle, and an increase in surface temperature increases the strength of the hydrological cycle. However, the physical processes that connect the atmospheric radiative energy budget to the sensible and latent heat fluxes at the surface remain not well understood. The responses to the two perturbations are linearly additive, and we find that the experiment with fixed surface temperature and changes in CO2 is of great relevance to understanding the total response. This result points to the importance of local radiative heating rate changes rather than just the net atmospheric radiative loss of energy. Although larger in magnitude, the response to changes in surface temperature is dominated by the temperature dependence of the water vapor pressure, but in both cases changes in near-surface relative humidity are very important.

  14. Calculation tool for transported geothermal energy using two-step absorption process

    DOE Data Explorer

    Kyle Gluesenkamp

    2016-02-01

    This spreadsheet allows the user to calculate parameters relevant to techno-economic performance of a two-step absorption process to transport low temperature geothermal heat some distance (1-20 miles) for use in building air conditioning. The parameters included are (1) energy density of aqueous LiBr and LiCl solutions, (2) transportation cost of trucking solution, and (3) equipment cost for the required chillers and cooling towers in the two-step absorption approach. More information is available in the included public report: "A Technical and Economic Analysis of an Innovative Two-Step Absorption System for Utilizing Low-Temperature Geothermal Resources to Condition Commercial Buildings"

  15. Optical registration of transformer oil absorption processes in electrical pressboard nano-capillaries

    NASA Astrophysics Data System (ADS)

    Rogalski, Przemysław

    2016-12-01

    The paper presents designed and built measurement system for measuring electrical pressboard oil absorption speed. During measurements the test bench allows for automatic record of oil level, time, temperature, humidity and atmospheric pressure. Measurements of Nytro Taurus oil, produced by Nynas company, absorption by pressboard, produced by Weidman company, were made. It has been observed, that the absorption of oil takes place in three stages, duration of which are respectively τ1≍0,66 h, τ2≍109 h and τ3≍524 h. It was established that the time required to complete the oil absorption process takes more than 46 days. This means that at least as much time should take oil impregnation process of pressboard samples made for electrical measurements.

  16. Simplification of the laser absorption process in the particle simulation for the laser-induced shockwave processing

    NASA Astrophysics Data System (ADS)

    Shimamura, Kohei

    2016-09-01

    To reduce the computational cost in the particle method for the numerical simulation of the laser plasma, we examined the simplification of the laser absorption process. Because the laser frequency is sufficiently larger than the collision frequency between the electron and heavy particles, we assumed that the electron obtained the constant value from the laser irradiation. First of all, the simplification of the laser absorption process was verified by the comparison of the EEDF and the laser-absorptivity with PIC-FDTD method. Secondary, the laser plasma induced by TEA CO2 laser in Argon atmosphere was modeled using the 1D3V DSMC method with the simplification of the laser-absorption. As a result, the LSDW was observed with the typical electron and neutral density distribution.

  17. FR-II Broad Absorption Line Quasars and the Life Cycle of Quasars

    SciTech Connect

    Gregg, M D; Becker, R H; de Vries, W

    2006-01-05

    By combining the Sloan Digitized Sky Survey Third Data Release quasar list with the VLA FIRST survey, we have identified five objects having both broad absorption lines in their optical spectra and FR-II radio morphologies. We identify an additional example of this class from the FIRST Bright Quasar Survey, J1408+3054. Including the original FR-II-BAL object, J1016+5209, brings the number of such objects to eight. These quasars are relatively rare; finding this small handful has required the 45,000-large quasar sample of SDSS. The FR-II-BAL quasars exhibit a significant anti-correlation between radio-loudness and the strength of the BAL features. This is easily accounted for by the evolutionary picture in which quasars emerge from cocoons of BAL-producing material which stifle the development of radio jets and lobes. There is no such simple explanation for the observed properties of FR-II-BALs in the unification-by-orientation model of quasars. The rarity of the FR-II-BAL class implies that the two phases do not coexist for very long in a single quasar, perhaps less than 10{sup 5} years, with the combined FR-II, high ionization broad absorption phase being even shorter by another factor of 10 or more.

  18. Research on filling process of fuel and oxidant during detonation based on absorption spectrum technology

    NASA Astrophysics Data System (ADS)

    Lv, Xiao-Jing; Li, Ning; Weng, Chun-Sheng

    2014-12-01

    Research on detonation process is of great significance for the control optimization of pulse detonation engine. Based on absorption spectrum technology, the filling process of fresh fuel and oxidant during detonation is researched. As one of the most important products, H2O is selected as the target of detonation diagnosis. Fiber distributed detonation test system is designed to enable the detonation diagnosis under adverse conditions in detonation process. The test system is verified to be reliable. Laser signals at different working frequency (5Hz, 10Hz and 20Hz) are detected. Change of relative laser intensity in one detonation circle is analyzed. The duration of filling process is inferred from the change of laser intensity, which is about 100~110ms. The peak of absorption spectrum is used to present the concentration of H2O during the filling process of fresh fuel and oxidant. Absorption spectrum is calculated, and the change of absorption peak is analyzed. Duration of filling process calculated with absorption peak consisted with the result inferred from the change of relative laser intensity. The pulse detonation engine worked normally and obtained the maximum thrust at 10Hz under experiment conditions. The results are verified through H2O gas concentration monitoring during detonation.

  19. Analysis of Cryogenic Cycle with Process Modeling Tool: Aspen HYSYS

    NASA Astrophysics Data System (ADS)

    Joshi, D. M.; Patel, H. K.

    2015-10-01

    Cryogenic engineering deals with the development and improvement of low temperature techniques, processes and equipment. A process simulator such as Aspen HYSYS, for the design, analysis, and optimization of process plants, has features that accommodate the special requirements and therefore can be used to simulate most cryogenic liquefaction and refrigeration processes. Liquefaction is the process of cooling or refrigerating a gas to a temperature below its critical temperature so that liquid can be formed at some suitable pressure which is below the critical pressure. Cryogenic processes require special attention in terms of the integration of various components like heat exchangers, Joule-Thompson Valve, Turbo expander and Compressor. Here, Aspen HYSYS, a process modeling tool, is used to understand the behavior of the complete plant. This paper presents the analysis of an air liquefaction plant based on the Linde cryogenic cycle, performed using the Aspen HYSYS process modeling tool. It covers the technique used to find the optimum values for getting the maximum liquefaction of the plant considering different constraints of other parameters. The analysis result so obtained gives clear idea in deciding various parameter values before implementation of the actual plant in the field. It also gives an idea about the productivity and profitability of the given configuration plant which leads to the design of an efficient productive plant.

  20. How automation helps steer the revenue cycle process.

    PubMed

    Colpas, Phil

    2013-06-01

    If there's one aspect of healthcare that's omnipresent - that is connected in some way to virtually every component of the medical trade - it's the revenue cycle; and vendors' solutions to manage it are as varied as the experts we queried on this topic. The revenue cycle actually touches on nearly everything related to healthcare - from the time a patient books an appointment with a healthcare facility, until the patient and insurance company provide final payments for services rendered to the healthcare provider. Over the past several decades, software programs and computers have replaced ledger books and calculators. And while the goal of revenue cycle management (RCM) remains essentially the same, healthcare reform will make this process infinitely more complex, due to reduced reimbursements and the onset of ICD-10 in October 2014. Additionally, reimbursement will be tied to quality, rather than quantity. According to an Information Week article by Ken Terry, outsourcing of billing and collections continues to grow, "because hospitals and physician groups are not very good at these non-core tasks." Think writers and math: I know a great many writers, including yours truly, who possess truly weak math skills. Granted, both skills involve opposite brain hemispheres - different parts of the brain. But what may be even more important is the fact that math is not generally an integral component of the main function of writing. A similar situation exists in healthcare facilities; just replace writing with providing care for people. A 2012 Black Book Rankings survey states 96 percent of organizations are in the process of acquiring several crucial accountable care organization (ACO) data solutions, including clinical decision support, RCM, health information exchange (HIEs), electronic health records (EHRs), e-prescribing, data center security and storage solutions, business intelligence and care coordination management. So it's clear that RCM will continue to remain a

  1. Study of absorption and re-emission processes in a ternary liquid scintillation system

    NASA Astrophysics Data System (ADS)

    Xiao, Hua-Lin; Li, Xiao-Bo; Zheng, Dong; Cao, Jun; Wen, Liang-Jian; Wang, Nai-Yan

    2010-11-01

    Liquid scintillators are widely used as the neutrino target in neutrino experiments. The absorption and emission of different components of a ternary liquid scintillator (Linear Alkyl Benzene (LAB) as the solvent, 2,5-diphenyloxazole (PPO) as the fluor and p-bis-(o-methylstyryl)-benzene (bis-MSB) as wavelength shifter) are studied. It is shown that the absorption of this liquid scintillator is dominant by LAB and PPO at wavelengths less than 349 nm, and the absorption by bis-MSB becomes prevalent at the wavelength larger than 349 nm. The fluorescence quantum yields, which are the key parameters to model the absorption and re-emission processes in large liquid scintillation detectors, are measured.

  2. Energy Absorption in a Load-Unload Cycle of Knee Implant Using Fractal Model of Rough Surfaces

    NASA Astrophysics Data System (ADS)

    Hodaei, Mohammad; Farhang, Kambiz

    2016-05-01

    Roughness measurement of knee implant surfaces is investigated. The study of roughness measurement show that the topography of knee implant surface is multi-scale and surface spectra follows a power law behavior. A magnification of rough surface topography implies that there is no difference between original and magnified profile of implant surface. For implant surface, statistical parameters such as variance of height, curvature, and slope are found to be scale-dependent. Fractal representation of implant surface shows that the size-distribution of the multi-scale contacts spots follows a power law and is characterized by the fractal dimension of implant surface. Fractal surface description of the rough surfaces of knee implant is used to obtain force-displacement relationship of the contact force. Using an approximate function through the fusion of two piecewise functions, energy absorption of a knee implant in a single cycle of load-unload is obtained.

  3. Multispecies breath analysis faster than a single respiratory cycle by optical-feedback cavity-enhanced absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Ventrillard-Courtillot, Irene; Gonthiez, Thierry; Clerici, Christine; Romanini, Daniel

    2009-11-01

    We demonstrate a first application, of optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS) to breath analysis in a medical environment. Noninvasive monitoring of trace species in exhaled air was performed simultaneous to spirometric measurements on patients at Bichat Hospital (Paris). The high selectivity of the OF-CEAS spectrometer and a time response of 0.3 s (limited by sample flow rate) allowed following the evolution of carbon monoxide and methane concentrations during individual respiratory cycles, and resolving variations among different ventilatory patterns. The minimum detectable absorption on this time scale is about 3×10-10 cm-1. At the working wavelength of the instrument (2.326 μm), this translates to concentration detection limits of ~1 ppbv (45 picomolar, or ~1.25 μg/m3) for CO and 25 ppbv for CH4, well below concentration values found in exhaled air. This same instrument is also able to provide measurement of NH3 concentrations with a detection limit of ~10 ppbv however, at present, memory effects do not allow its measurement on fast time scales.

  4. Experimental study for a double glazed forced-convection solar collector/regenerator for open-cycle absorption cooling system

    SciTech Connect

    Yang, R.; Wang, P.L.

    1996-12-31

    Experimental study of a double-glazed forced-convection solar collector/regenerator for absorption solar cooling is presented. The south facing experimental solar collector/regenerator with 10{degree} slope is located at Kaohsiung, Taiwan at 120{degree}18minuteE longitude and 22{degree}34minuteN latitude. The size of the collector is 1m wide and 7m long. Previous study for single-glazed forced-convection solar collector/regenerator operated at the same location has shown to have a best day-average efficiency of 17%. In order to raise the system performance, a double-glazed collector/regenerator is constructed such that air can be pre-heated in the upper channel flow. The pre-heated air is then conducted into the lower channel where it contacts with the film flow of solar heated lithium-chloride solutions and regenerates the solution by carrying out the evaporated water vapor. Since the preheated air has lower relative humidity ratio, the regeneration driving potential is increased. The present study shows that the best day-average efficiency can reach 20% which increases the feasibility of the open-cycle absorption solar cooling system. Effects of controlling parameters on the collector/regenerator performance are studied, and heat and mass transfer correlations are also presented for design purposes.

  5. Stability of IRA-45 solid amine resin as a function of carbon dioxide absorption and steam desorption cycling

    NASA Technical Reports Server (NTRS)

    Wood, Peter C.; Wydeven, Theodore

    1987-01-01

    The removal of CO2 from the NASA Space Station's cabin atmosphere, which may be undertaken by a solid-amine water (steam)-desorbed system, is presently evaluated with a view to long-term amine resin stability and adsorption/desorption cycling by means of an automated laboratory flow-testing facility. While the CO2-adsorption capacity of the IRA-45 amine resin used gradually decreased over time, the rate of degradation significantly decreased after the first 10 cycles. Attention is given to the presence (and possible need for removal) of trimethylamine in the process air downstream of the resin bed.

  6. Performance evaluation of single-glazed and double glazed collectors/regenerators for an open cycle absorption solar cooling system

    SciTech Connect

    Yang, R.; Wang, P.L.

    1998-07-01

    Feasibility for an open-cycle absorption solar cooling system operated in Kaohsiung, Taiwan is studied via a computer simulation program using previous obtained experimental correlations for the collector/regenerator (C/R) performance and the TMY data of Kaohsiung, Taiwan. Three C/R models are considered in this study. They are the natural and the forced convection single-glazed Cs/Rs and the forced convection double-glazed C/R. The effects of the C/R area, the C/R solution flow rate, the solution storage, the chilled water temperature and the daily cooling demand on the system performance in terms of seasonal solar fraction are studied and discussed. The results show that the solar C/R is the key component of the cooling system and the open-cycle absorption system is a sound solar cooling system. It is shown that the double glazed forced convection C/R gives a better system performance. The simulation study is to evaluate the seasonal solar fraction, which is defined as F=(solar cooling load)/(total cooling load) Firstly, all three C/R models are simulated under the base case conditions. The seasonal averaged solar fraction for three models are found to be 0.7, 0.75 and 0.79, respectively, while the corresponding seasonal averaged C/R efficiencies are 15.7%, 18.4% and 20.6%. The double-glazed forced convection system performs better than the other two systems. This is consistent with the results of previous experimental studies for the C/R. A nearly linear relationship between the C/R efficiency and the solar fraction is shown. The solar fraction increases slightly with the solution storage volume for the natural convection case, but it is much more sensitive to the solution storage for the forced convection system. The solar fraction is relatively insensitive to the C/R area after a critical value is reached. A similar dependence is also found in other solar absorption air conditioning system alternatives.

  7. A cost-effective and fuel-conserving nonelectric air conditioner that combines engine-driven compression and absorption cycles

    SciTech Connect

    Wicks, F.

    1988-01-01

    A natural-gas-fueled electricity-producing condensing furnace with the potential of being mass produced at a cost of less than $1000 and providing a cost-effective and highly fuel-conserving alternative to virtually every residential gas furnace in the world has been developed. While this is a new system, it completely consists of existing mass-produced components including single-cylinder air-cooled engines, induction motors/generators, and control devices. Thus, timely commercialization can be expected and an important new energy technology and industry can result. However, all the benefits of this electricity-producing furnace occur during the winter. This has stimulated the search for a new system that can provide comparable benefits in terms of fuel conservation, the environment, and electric utility peak reduction during the summer, along with the prospects of a new and efficient new use for the natural gas surpluses that occur during the summer. The resulting system, which can use existing component equipment, is a commercial-size nonelectric air conditioner that consists of an automobile-type engine converted to natural gas, or possibly a diesel or combustion turbine, driving a Freon compression cycle, with virtually all of the engine reject heat from the exhaust and from the engine cooling system driving a conventional absorption air conditioning cycle.

  8. [Effects and mechanism of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem].

    PubMed

    Wang, Li-qin; Qi, Yu-chun; Dong, Yun-she; Peng, Qin; Guo, Shu-fang; He, Yun-long; Yan, Zhong-qing

    2015-11-01

    As a widespread natural phenomenon in the soil of middle and high latitude as well as high altitude, freeze-thawing cycles have a great influence on the nitrogen cycle of terrestrial ecosystem in non-growing season. Freeze-thawing cycles can alter the physicochemical and biological properties of the soil, which thereby affect the migration and transformation of soil nitrogen. The impacts of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem found in available studies remain inconsistent, the mechanism is still not clear, and the research methods also need to be further explored and innovated. So it is necessary to sum up and analyze the existing achievements in order to better understand the processes of soil nitrogen cycle subjected to freeze-thawing cycles. This paper reviewed the research progress in China and abroad about the effects and mechanisms of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem, including mineralization, immobilization, nitrification and denitrification, N leakage and gaseous loss, and analyzed the deficiencies of extant research. The possible key research topics that should be urgently paid more attention to in the future were also discussed.

  9. IFR fuel cycle process equipment design environment and objectives

    SciTech Connect

    Rigg, R.H.

    1993-03-01

    Argonne National laboratory (ANL) is refurbishing the hot cell facility originally constructed with the EBR-II reactor. When refurbishment is complete, the facility win demonstrate the complete fuel cycle for current generation high burnup metallic fuel elements. These are sodium bonded, stainless steel clad fuel pins of U-Zr or U-Pu-Zr composition typical of the fuel type proposed for a future Integral Fast Reactor (IFR) design. To the extent possible, the process equipment is being built at full commercial scale, and the facility is being modified to incorporate current DOE facility design requirements and modem remote maintenance principles. The current regulatory and safety environment has affected the design of the fuel fabrication equipment, most of which will be described in greater detail in subsequent papers in this session.

  10. IFR fuel cycle process equipment design environment and objectives

    SciTech Connect

    Rigg, R.H.

    1993-01-01

    Argonne National laboratory (ANL) is refurbishing the hot cell facility originally constructed with the EBR-II reactor. When refurbishment is complete, the facility win demonstrate the complete fuel cycle for current generation high burnup metallic fuel elements. These are sodium bonded, stainless steel clad fuel pins of U-Zr or U-Pu-Zr composition typical of the fuel type proposed for a future Integral Fast Reactor (IFR) design. To the extent possible, the process equipment is being built at full commercial scale, and the facility is being modified to incorporate current DOE facility design requirements and modem remote maintenance principles. The current regulatory and safety environment has affected the design of the fuel fabrication equipment, most of which will be described in greater detail in subsequent papers in this session.

  11. Nitrite isotopes as tracers of marine N cycle processes

    NASA Astrophysics Data System (ADS)

    Casciotti, Karen L.

    2016-11-01

    Nitrite (NO2-) is a key intermediate in the marine nitrogen (N) cycle. It is produced and consumed throughout the ocean by the dominant processes driving the distribution, availability and speciation of N. However, the accumulation of nitrite is typically confined to depths near the base of the sunlit euphotic zone and in oxygen-deficient zones. These features are known as the primary and secondary nitrite maximum (PNM and SNM), respectively. The processes controlling nitrite accumulation in these features are not fully understood, but are thought to depend on the microbial community composition and its response to environmental conditions. A variety of approaches have been applied to understanding these features since their discovery, with the stable N and oxygen (O) isotope measurements of nitrite being added to this toolkit most recently. Large variations in nitrite N isotope ratios (15N/14N) and dramatic depletions in 15N contrast with more consistent nitrite O isotope ratios (18O/16O) in the SNM. These signals provide unique information about the mechanisms of nitrite consumption in the SNM. By contrast, nitrite in the PNM shows less variation in 15N/14N, but variations in 18O/16O that provide insight into the mechanisms and rates of N cycling there. This review presents a synthesis of nitrite isotope measurements in the marine environment, highlighting the insights that have been gained from these measurements. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  12. Antecedents of Absorptive Capacity: A New Model for Developing Learning Processes

    ERIC Educational Resources Information Center

    Rezaei-Zadeh, Mohammad; Darwish, Tamer K.

    2016-01-01

    Purpose: The purpose of this paper is to provide an integrated framework to indicate which antecedents of absorptive capacity (AC) influence its learning processes, and to propose testing of this model in future work. Design/methodology/approach Relevant literature into the antecedents of AC was critically reviewed and analysed with the objective…

  13. Capillary absorption spectrometer and process for isotopic analysis of small samples

    DOEpatents

    Alexander, M. Lizabeth; Kelly, James F.; Sams, Robert L.; Moran, James J.; Newburn, Matthew K.; Blake, Thomas A.

    2016-03-29

    A capillary absorption spectrometer and process are described that provide highly sensitive and accurate stable absorption measurements of analytes in a sample gas that may include isotopologues of carbon and oxygen obtained from gas and biological samples. It further provides isotopic images of microbial communities that allow tracking of nutrients at the single cell level. It further targets naturally occurring variations in carbon and oxygen isotopes that avoids need for expensive isotopically labeled mixtures which allows study of samples taken from the field without modification. The method also permits sampling in vivo permitting real-time ambient studies of microbial communities.

  14. Data processing and calibration for tunable diode laser harmonic absorption spectrometers

    NASA Technical Reports Server (NTRS)

    May, Randy D.; Webster, Christopher R.

    1993-01-01

    Data processing and calibration methods are described for tunable diode laser absorption spectrometers which produce harmonic absorption spectra as raw data for measuring gas mixing ratios down to parts-per-trillion levels at a variety of pressures. The methods, which take advantage of modern computer speed, memory, and data storage capabilities, are applicable to the detection of weakly absorbing gases in quantitative industrial monitoring, in addition to aircraft and balloon atmospheric measurements for which they were designed. Algorithms for calibration and data analysis, including rejection of erroneous spectra, variation of effective integration time, spectral alignment prior to averaging, and plotting and archiving of results, have been tested on actual stratospheric laser spectra recorded by the Aircraft Laser Infrared Absorption Spectrometer (ALIAS) spectrometer in numerous flights of NASA's ER-2 aircraft.

  15. Data processing and calibration for tunable diode laser harmonic absorption spectrometers

    NASA Technical Reports Server (NTRS)

    May, Randy D.; Webster, Christopher R.

    1993-01-01

    Data processing and calibration methods are described for tunable diode laser absorption spectrometers which produce harmonic absorption spectra as raw data for measuring gas mixing ratios down to parts-per-trillion levels at a variety of pressures. The methods, which take advantage of modern computer speed, memory, and data storage capabilities, are applicable to the detection of weakly absorbing gases in quantitative industrial monitoring, in addition to aircraft and balloon atmospheric measurements for which they were designed. Algorithms for calibration and data analysis, including rejection of erroneous spectra, variation of effective integration time, spectral alignment prior to averaging, and plotting and archiving of results, have been tested on actual stratospheric laser spectra recorded by the Aircraft Laser Infrared Absorption Spectrometer (ALIAS) spectrometer in numerous flights of NASA's ER-2 aircraft.

  16. Potential synergy: the thorium fuel cycle and rare earths processing

    SciTech Connect

    Ault, T.; Wymer, R.; Croff, A.; Krahn, S.

    2013-07-01

    The use of thorium in nuclear power programs has been evaluated on a recurring basis. A concern often raised is the lack of 'thorium infrastructure'; however, for at least a part of a potential thorium fuel cycle, this may less of a problem than previously thought. Thorium is frequently encountered in association with rare earth elements and, since the U.S. last systematically evaluated the large-scale use of thorium (the 1970's,) the use of rare earth elements has increased ten-fold to approximately 200,000 metric tons per year. Integration of thorium extraction with rare earth processing has been previously described and top-level estimates have been done on thorium resource availability; however, since ores and mining operations differ markedly, what is needed is process flowsheet analysis to determine whether a specific mining operation can feasibly produce thorium as a by-product. Also, the collocation of thorium with rare earths means that, even if a thorium product stream is not developed, its presence in mining waste streams needs to be addressed and there are previous instances where this has caused issues. This study analyzes several operational mines, estimates the mines' ability to produce a thorium by-product stream, and discusses some waste management implications of recovering thorium. (authors)

  17. Superhydrophobic and superoleophilic polydimethylsiloxane-coated cotton for oil-water separation process: An evidence of the relationship between its loading capacity and oil absorption ability.

    PubMed

    Jin, Yangxin; Jiang, Peng; Ke, Qingping; Cheng, Feihuan; Zhu, Yinshengnan; Zhang, Yixiang

    2015-12-30

    Developing functional porous materials with highly efficient oil-water separation ability are of great importance due to the global scale of severe water pollution arising from oil spillage and chemical leakage. A solution immersion process was used to fabricate polydimethylsiloxane (PDMS)-coated cotton, which exhibited superhydrophobic and superoleophilic properties. The water contact angle of ∼ 157° and mass of ∼ 1.49 g were retained after 1000 compression cycles, indicating that the PDMS was strongly attached to the cotton fibres. The PDMS-coated cotton absorbed various oils and organic solvents with high selectivity, high absorption capacity (up to 7080 wt.%), and good recyclability (exceeding 500 cycles). Notably, the loading capacity of the PDMS-coated cotton against water exhibited a similar trend to its oil absorption capacity. These findings will further the application of superhydrophobic and superoleophilic porous materials in oil/water separation.

  18. Impacts of Combustion Conditions and Photochemical Processing on the Light Absorption of Biomass Combustion Aerosol.

    PubMed

    Martinsson, J; Eriksson, A C; Nielsen, I Elbæk; Malmborg, V Berg; Ahlberg, E; Andersen, C; Lindgren, R; Nyström, R; Nordin, E Z; Brune, W H; Svenningsson, B; Swietlicki, E; Boman, C; Pagels, J H

    2015-12-15

    The aim was to identify relationships between combustion conditions, particle characteristics, and optical properties of fresh and photochemically processed emissions from biomass combustion. The combustion conditions included nominal and high burn rate operation and individual combustion phases from a conventional wood stove. Low temperature pyrolysis upon fuel addition resulted in "tar-ball" type particles dominated by organic aerosol with an absorption Ångström exponent (AAE) of 2.5-2.7 and estimated Brown Carbon contributions of 50-70% to absorption at the climate relevant aethalometer-wavelength (520 nm). High temperature combustion during the intermediate (flaming) phase was dominated by soot agglomerates with AAE 1.0-1.2 and 85-100% of absorption at 520 nm attributed to Black Carbon. Intense photochemical processing of high burn rate flaming combustion emissions in an oxidation flow reactor led to strong formation of Secondary Organic Aerosol, with no or weak absorption. PM1 mass emission factors (mg/kg) of fresh emissions were about an order of magnitude higher for low temperature pyrolysis compared to high temperature combustion. However, emission factors describing the absorption cross section emitted per kg of fuel consumed (m(2)/kg) were of similar magnitude at 520 nm for the diverse combustion conditions investigated in this study. These results provide a link between biomass combustion conditions, emitted particle types, and their optical properties in fresh and processed plumes which can be of value for source apportionment and balanced mitigation of biomass combustion emissions from a climate and health perspective.

  19. Biogeochemical processes driving mercury cycling in estuarine ecosystems

    NASA Astrophysics Data System (ADS)

    Schartup, A. T.

    2015-12-01

    Mercury (Hg) is a naturally occurring element that has been enriched in the environment through human activities, particularly in the coastal zone. Bioaccumulation of methylmercury (MeHg) in marine fishposes health risks for fish-consuming populations and is a worldwide health concern. A broader understanding of major environmental processes controlling Hg cycling and MeHg production and bioaccumulation in estuaries is therefore needed. Recent fieldwork and modeling show diverse sources of MeHg production in estuaries. We present geochemical modeling results for Hg and MeHg acrossmultiple estuaries with contrasting physical, chemical and biological characteristics. We report new measurements of water column and sediment mercury speciation and methylation data from the subarctic (Lake Melville, Labrador Canada) and temperate latitudes (Long Island Sound, Delaware Bay, Chesapeake Bay). We find that benthic sediment is a relatively small source of MeHg to the water column in all systems. Water column methylation drives MeHg levels in Lake Melville, whereas in more impacted shallow systems such as Chesapeake Bay and Long Island Sound, external inputs and sediment resuspension are more dominant. All systems are a net source of MeHg to the ocean through tidal exchange. In light of these inter-system differences, we will evaluate timescales of coastal ecosystem responses to changes in Hg loading that can help predict potential responses to future perturbations.

  20. Effects of Initial Pore Diameter on the Oil Absorption Behavior of Potato Chips during Frying Process.

    PubMed

    Li, Jinwei; Zhang, Tingting; Liu, Yuanfa; Fan, Liuping

    2016-01-01

    How initial pore diameter in materials affects oil absorption has been rarely studied up to now. Herein, we provided direct data evidence suggesting that the pore diameter prior to frying closely related to the oil absorption behavior. The pore had no significant effect on oil absorption of potato chips (p>0.05) when its diameter was 0.1 and 0.2 mm compared with the control. However, the oil absorption increased with the increasing of pore diameter when it was 0.3-1.2 mm. The oil absorption tended to be saturated at 0.9 mm pore diameter. In addition, we analyzed the moisture content, total oil (TO), surface oil (SO), penetrated surface oil (PSO) and structural oil (STO) contents of potato chips. The results when using palm oil showed that there was no significant difference in moisture, TO and STO contents of samples with pore diameter of 0.1 and 0.2 mm during the whole frying processing respectively compared with the control (p>0.05). When pore diameter was 0.3-1.2 mm, STO and TO contents significantly increased with the rising of the diameter (p<0.05). The SO content and PSO content dropped as increasing in frying time for the samples with different pore diameters. The equilibrium TO content of samples with 0.3-0.9 mm pore significantly increased with the rising of pore diameter, which was about 6.2-22.5% higher than that of the control. And there was no significant difference in the equilibrium TO contents of both samples of 1.2 mm and 0.9 mm pore (p>0.05). STO fraction gave the greatest contribution to the increment of oil absorption.

  1. 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.

  2. A learning process of water cycle as complex system

    NASA Astrophysics Data System (ADS)

    Schertzer, D.; Deroubaix, J. F.; Tchiguirinskaia, I.; Tassin, B.; Thevenot, D.

    2009-04-01

    Water cycle is a very good example of a complex geosystem which has many societal impacts and drivers. A permanent and ubiquitous question is how to increase public awareness and understanding of its extreme behaviours, as well as of the related uncertainties. For instance, CEREVE is highly solicited to help the general public, particularly the youth, and the local politicians to get better acquainted with the new water culture in general and with flood risks in particular, in the nearby county Val-de-Marne. Since 2001, May is the month of the "Festival de l'Oh"(which sounds like "Festival de l'Eau", i.e. the water festival co-organized by the county council and city of Paris. "Oh » at the same time partly displays the chemical composition of water and is an exclamation for atonishment). This festival starts with the Scientific Days of Environment that involve researchers and students of the county, as well as collaborators of all around the world. This conference is open to the public who can be informed from the latest research developments, in particular with the help of some general synthesis and panel discussions. On the other hand, (young) researchers can present their own works to a large public. This conference is followed by a Professional Forum where students, heads of water public services or private operators can meet. In the framework of the water festival preparation, there are several water forums for the secondary schools. All along the year, there are regular pedagogical activities for secondary schools, in particular in the framework of Water Houses scattered across the county. We will discuss the importance to better evaluate the effective impact of these pedagogical events on the public awareness and understanding, and to make the learning process more adaptive and interactive, as well as to better address the underlying fundamental problems, e.g. the present limitations of current modelling and data processing.

  3. CNG process, a new approach to physical-absorption acid-gas removal

    SciTech Connect

    Hise, R.E.; Massey, L.G.; Adler, R.J.; Brosilow, C.B.; Gardner, N.C.; Brown, W.R.; Cook, W.J.; Petrik, M.

    1982-01-01

    The CNG acid gas removal process embodies three novel features: (1) scrubbing with liquid carbon dioxide to remove all sulfurous molecules and other trace contaminants; (2) triple-point crystallization of carbon dioxide to concentrate sulfurous molecules and produce pure carbon dioxide; and (3) absorption of carbon dioxide with a slurry of solid carbon dioxide in organic carrier liquid. The CNG process is discussed and contrasted with existing acid gas removal technology as represented by the Benfield, Rectisol, and Selexol acid gas removal processes.

  4. The solvent absorption-extractive distillation (SAED) process for ethanol recovery from gas/vapor streams

    SciTech Connect

    Dale, M.C.

    1993-12-31

    A low energy system for ethanol recovery and dehydration has been developed. This system utilizes a solvent for (1) absorption of ethanol vapors, and then the same solvent for (2) extractive distillation. The ideal solvent for this process would have a high affinity for ethanol, and no affinity for water. Heavy alcohols such as dodecanol, and tridecanol, some phosphorals, and some fatty acids have been determined to meet the desired specifications. These solvents have the effect of making water more volatile than ethanol. Thus, a water stream is taken off initially in the dehydration column, and a near anhydrous ethanol stream is recovered from the ethanol/solvent stripper column. Thus the solvent serves dual uses (1) absorption media, and (2) dehydration media. The SAED process as conceptualized would use a solvent similar to solvents used for direct extractive separation of ethanol from aqueous ethanol solutions.

  5. The imaging and modelling of the physical processes involved in digestion and absorption.

    PubMed

    Schulze, K S

    2015-02-01

    The mechanical activity of the gastro-intestinal tract serves to store, propel and digest food. Contractions disperse particles and transform solids and secretions into the two-phase slurry called chyme; movements of the intestine deliver nutrients to mucosal sites of absorption, and from the submucosa into the lymphatic and portal venous circulation. Colonic motor activity helps to extract fluid and electrolytes from chyme and to compound and compact luminal debris into faeces for elimination. We outline how dynamic imaging by ultrasound and magnetic resonance can demonstrate intestinal flow processes critical to digestion like mixing, dilution, swelling, dispersion and elution. Computational fluid mechanics enables a numerical rendition of the forces promoting digestion: pressure and flow fields, the shear stresses dispersing particles or the effectiveness of bolus mixing can be calculated. These technologies provide new insights into the mechanical processes that promote digestion and absorption.

  6. Finite element analysis and modeling of water absorption by date pits during a soaking process.

    PubMed

    Waezi-Zadeh, Motahareh; Ghazanfari, Ahmad; Noorbakhsh, Shahin

    2010-07-01

    Date pits for feed preparation or oil extraction are soaked in water to soften before milling or extrusion. Knowledge of water absorption by the date pits helps in better managing the soaking duration. In this research, the process of water absorption by date pits was modeled and analyzed using Fick's second law of diffusion, finite element approach, and Peleg model. The moisture content of the pits reached to its saturation level of 41.5% (wet basis) after 10 d. The estimated coefficient of diffusion was 9.89x10(-12) m(2)/s. The finite element model with a proposed ellipsoid geometry for a single date pit and the analytical model fitted better to the experimental data with R(2) of 0.98. The former model slightly overestimated the moisture content of the pits during the initial stages of the soaking and the latter model generally underestimated this variable through the entire stages of soaking process.

  7. Salt Processing Project: Off-Line Analysis Methods to Meet Process Cycle Time

    SciTech Connect

    Sigg, R.A.

    2002-10-18

    The Salt Waste Processing Facility (SWPF) requires analyses to verify that strontium and total alpha content of treated wastes meet Saltstone Processing Facility (SPF) Waste Acceptance Criteria (WAC). The SWPF will require that results are available in time to meet process cycle requirements. SWPF personnel sought on-line and at-line monitors to follow trends in strontium-90 and alpha concentrations in order to track process performance. While an on-line method is under development at the Pacific Northwest National Laboratory (PNNL), it has yet to be demonstrated. This report describes off-line methods that will not be subject to some of the concerns about and limitations of on-line/at-line methods. Presently, less-rapid off-line technologies are the baseline methods. Also, this report compares advantages and disadvantages of a variety of approaches including rapid radiochemical separations, automated analytical-scale processing systems, and radiation measurement tools.

  8. Regeneration of an aqueous solution from an acid gas absorption process by matrix stripping

    DOEpatents

    Rochelle, Gary T [Austin, TX; Oyenekan, Babatunde A [Katy, TX

    2011-03-08

    Carbon dioxide and other acid gases are removed from gaseous streams using aqueous absorption and stripping processes. By replacing the conventional stripper used to regenerate the aqueous solvent and capture the acid gas with a matrix stripping configuration, less energy is consumed. The matrix stripping configuration uses two or more reboiled strippers at different pressures. The rich feed from the absorption equipment is split among the strippers, and partially regenerated solvent from the highest pressure stripper flows to the middle of sequentially lower pressure strippers in a "matrix" pattern. By selecting certain parameters of the matrix stripping configuration such that the total energy required by the strippers to achieve a desired percentage of acid gas removal from the gaseous stream is minimized, further energy savings can be realized.

  9. Decoupling absorption and emission processes in super-resolution localization of emitters in a plasmonic hotspot

    NASA Astrophysics Data System (ADS)

    Mack, David L.; Cortés, Emiliano; Giannini, Vincenzo; Török, Peter; Roschuk, Tyler; Maier, Stefan A.

    2017-02-01

    The absorption process of an emitter close to a plasmonic antenna is enhanced due to strong local electromagnetic (EM) fields. The emission, if resonant with the plasmonic system, re-radiates to the far-field by coupling with the antenna via plasmonic states, whose presence increases the local density of states. Far-field collection of the emission of single molecules close to plasmonic antennas, therefore, provides mixed information of both the local EM field strength and the local density of states. Moreover, super-resolution localizations from these emission-coupled events do not report the real position of the molecules. Here we propose using a fluorescent molecule with a large Stokes shift in order to spectrally decouple the emission from the plasmonic system, leaving the absorption strongly resonant with the antenna's enhanced EM fields. We demonstrate that this technique provides an effective way of mapping the EM field or the local density of states with nanometre spatial resolution.

  10. Decoupling absorption and emission processes in super-resolution localization of emitters in a plasmonic hotspot

    PubMed Central

    Mack, David L.; Cortés, Emiliano; Giannini, Vincenzo; Török, Peter; Roschuk, Tyler; Maier, Stefan A.

    2017-01-01

    The absorption process of an emitter close to a plasmonic antenna is enhanced due to strong local electromagnetic (EM) fields. The emission, if resonant with the plasmonic system, re-radiates to the far-field by coupling with the antenna via plasmonic states, whose presence increases the local density of states. Far-field collection of the emission of single molecules close to plasmonic antennas, therefore, provides mixed information of both the local EM field strength and the local density of states. Moreover, super-resolution localizations from these emission-coupled events do not report the real position of the molecules. Here we propose using a fluorescent molecule with a large Stokes shift in order to spectrally decouple the emission from the plasmonic system, leaving the absorption strongly resonant with the antenna's enhanced EM fields. We demonstrate that this technique provides an effective way of mapping the EM field or the local density of states with nanometre spatial resolution. PMID:28211479

  11. Reduction of VOC emissions by a membrane-based gas absorption process.

    PubMed

    Li, Rui; Xu, Jun; Wang, Lianjun; Li, Jiansheng; Sun, Xiuyun

    2009-01-01

    A membrane-based gas absorption (MGA) process was evaluated for the removal of volatile organic compounds (VOCs) based on C6H6/N2 mixture. The absorption of C6H6 from a C6H6/N2 mixture was investigated using a hydrophobic polypropylene hollow fiber membrane contactor and the aqueous solution of N-formyl morpholine (NFM) as absorbent. The effects of various factors on the overall mass transfer coefficient was investigated. The experimental results showed that the removal efficiency of C6H6 could reach 99.5% in present studied system. A mathematical model based on resistance-in-series concept was presented to predict the value of overall mass transfer coefficient. The average error between the predicted and experimental values is 7.9%. In addition, conventional packed columns for VOCs removal was also evaluated for comparison.

  12. A Life Cycle Assessment on a Fuel Production Through Distributed Biomass Gasification Process

    NASA Astrophysics Data System (ADS)

    Dowaki, Kiyoshi; Eguchi, Tsutomu; Ohkubo, Rui; Genchi, Yutaka

    In this paper, we estimated life cycle inventories (energy intensities and CO2 emissions) on the biomass gasification CGS, Bio-H2, Bio-MeOH (methanol) and Bio-DME (di-methyl ether), using the bottom-up methodology. CO2 emissions and energy intensities on material's chipping, transportation and dryer operation were estimated. Also, the uncertainties on the moisture content of biomass materials and the transportation distance to the plant were considered by the Monte Carlo simulation. The energy conversion system was built up by gasification through the BLUE Tower process, with either CGS, PSA (Pressure Swing Absorption) system or the liquefaction process. In our estimation, the biomass materials were the waste products from Japanese Cedar. The uncertainties of moisture content and transportation distance were assumed to be 20 to 50 wt.% and 5 to 50 km, respectively. The capability of the biomass gasification plant was 10 t-dry/d, that is, an annual throughput of 3,000 t-dry/yr. The production energy in each case was used as a functional unit. Finally, the energy intensities of 1.12 to 3.09 MJ/MJ and CO2 emissions of 4.79 to 88.0 g-CO2/MJ were obtained. CGS case contributes to the environmental mitigation, and Bio-H2 and/or Bio-DME cases have a potential to reduce CO2 emissions, compared to the conventional ones.

  13. 62 FR 46525 - Chemical Process Safety at Fuel Cycle Facilities; Availability of NUREG

    Federal Register 2010, 2011, 2012, 2013, 2014

    1997-09-03

    ... COMMISSION Chemical Process Safety at Fuel Cycle Facilities; Availability of NUREG AGENCY: Nuclear Regulatory... completion and availability of NUREG-1601, ``Chemical Process Safety at Fuel Cycle Facilities,'' dated July.... SUPPLEMENTARY INFORMATION: NRC is announcing the availability of NUREG-1601, ``Chemical Process Safety at...

  14. 77 FR 823 - Guidance for Fuel Cycle Facility Change Processes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-06

    ... electronically under ADAMS Accession Number ML100890016. The regulatory analysis may be found in ADAMS under.... FOR FURTHER INFORMATION CONTACT: R. A. Jervey, U.S. Nuclear Regulatory Commission, Washington, DC... for tracking, evaluating, and documenting changes made to fuel cycle facilities, and to...

  15. Measuring elemental time and duty cycle using automated video processing.

    PubMed

    Akkas, Oguz; Lee, Cheng-Hsien; Hu, Yu Hen; Yen, Thomas Y; Radwin, Robert G

    2016-11-01

    A marker-less 2D video algorithm measured hand kinematics (location, velocity and acceleration) in a paced repetitive laboratory task for varying hand activity levels (HAL). The decision tree (DT) algorithm identified the trajectory of the hand using spatiotemporal relationships during the exertion and rest states. The feature vector training (FVT) method utilised the k-nearest neighbourhood classifier, trained using a set of samples or the first cycle. The average duty cycle (DC) error using the DT algorithm was 2.7%. The FVT algorithm had an average 3.3% error when trained using the first cycle sample of each repetitive task, and had a 2.8% average error when trained using several representative repetitive cycles. Error for HAL was 0.1 for both algorithms, which was considered negligible. Elemental time, stratified by task and subject, were not statistically different from ground truth (p < 0.05). Both algorithms performed well for automatically measuring elapsed time, DC and HAL. Practitioner Summary: A completely automated approach for measuring elapsed time and DC was developed using marker-less video tracking and the tracked kinematic record. Such an approach is automatic, repeatable, objective and unobtrusive, and is suitable for evaluating repetitive exertions, muscle fatigue and manual tasks.

  16. Life Cycle Assessment Software for Product and Process Sustainability Analysis

    ERIC Educational Resources Information Center

    Vervaeke, Marina

    2012-01-01

    In recent years, life cycle assessment (LCA), a methodology for assessment of environmental impacts of products and services, has become increasingly important. This methodology is applied by decision makers in industry and policy, product developers, environmental managers, and other non-LCA specialists working on environmental issues in a wide…

  17. Life Cycle Assessment Software for Product and Process Sustainability Analysis

    ERIC Educational Resources Information Center

    Vervaeke, Marina

    2012-01-01

    In recent years, life cycle assessment (LCA), a methodology for assessment of environmental impacts of products and services, has become increasingly important. This methodology is applied by decision makers in industry and policy, product developers, environmental managers, and other non-LCA specialists working on environmental issues in a wide…

  18. Restoration effects on N cycling pools and processes

    Treesearch

    James M. Vose; Chris Geron; John Walker; Karsten Raulund-Rasmussen

    2005-01-01

    Over the past several years, there has been an acceleration of restoration efforts to mitigate the consequences (i.e., ground and surface water chemical pollutants, erosion, etc.) of degraded ecosystems and enhance structural and functional components of watershed ecosystems that regulate biogeochemical cycling and associated aquatic components. Biogeochemical...

  19. Open cycle liquid desiccant dehumidifier and hybrid solar/electric absorption refrigeration system. Annual report, January 1993--December 1993. Calendar year 1993

    SciTech Connect

    Nimmo, B.G.; Thornbloom, M.D.

    1995-04-01

    This annual report presents work performed during calendar year 1993 by the Florida Solar Energy Center under contract to the US Department of Energy. Two distinctively different solar powered indoor climate control systems were analyzed: the open cycle liquid desiccant dehumidifier, and an improved efficiency absorption system which may be fired by flat plate solar collectors. Both tasks represent new directions relative to prior FSEC research in Solar Cooling and Dehumidification.

  20. Development of a carbonate absorption-based process for post-combustion CO2 capture: The role of biocatalyst to promote CO2 absorption rate

    USGS Publications Warehouse

    Lu, Y.; Ye, X.; Zhang, Z.; Khodayari, A.; Djukadi, T.

    2011-01-01

    An Integrated Vacuum Carbonate Absorption Process (IVCAP) for post-combustion carbon dioxide (CO2) capture is described. IVCAP employs potassium carbonate (PC) as a solvent, uses waste or low quality steam from the power plant for CO2 stripping, and employs a biocatalyst, carbonic anhydrase (CA) enzyme, for promoting the CO2 absorption into PC solution. A series of experiments were performed to evaluate the activity of CA enzyme mixed in PC solutions in a stirred tank reactor system under various temperatures, CA dosages, CO2 loadings, CO2 partial pressures, and the presence of major flue gas contaminants. It was demonstrated that CA enzyme is an effective biocatalyst for CO2 absorption under IVCAP conditions. ?? 2011 Published by Elsevier Ltd.

  1. Fabrication process and electromagnetic wave absorption characterization of a CNT/Ni/epoxy nanocomposite.

    PubMed

    Ryu, Seongwoo; Mo, Chan Bin; Lee, Haeshin; Hong, Soon Hyung

    2013-11-01

    Since carbon nanotube (CNT) was first discovered in 1991, it has been considered as a viable type of conductive filler for electromagnetic wave absorption materials in the GHz range. In this paper, pearl-necklace-structure CNT/Ni nano-powders were fabricated by a polyol process as conductive fillers. Compared to synthesized CNT, pearl-necklace Ni-decorated CNT increased the electrical conductivity by an order of 1 due to the enhancement of the Ni-conductive network. Moreover, the decorated Ni particles prevented the agglomeration of CNTs by counterbalancing the Van der Walls interaction between the CNTs. A CNT/Ni nanocomposite showed a homogeneous dispersion in an epoxy-based matrix. This enhanced physical morphology and electrical properties lead to an increase in the loss tangent and reflection loss in the CNT/Ni/Epoxy nanocomposite compared to these characteristics of a CNT/Epoxy nanocomposite in range of 8-12 GHz. The electromagnetic wave absorption properties of CNT/Ni/epoxy nanocomposites will provide enormous opportunities for electronic applications where lightweight EMI shielding or electro-magnetic wave absorption properties are necessary.

  2. Two-photon absorption cross section determination for fluorene derivatives: analysis of the methodology and elucidation of the origin of the absorption processes.

    PubMed

    Belfield, Kevin D; Bondar, Mykhailo V; Hernandez, Florencio E; Przhonska, Olga V; Yao, Sheng

    2007-11-08

    A comprehensive analysis of the well-known open aperture Z-scan method, using a modified equation for the change in transmittance, is presented and accounts for discrepancies in two-photon absorption (2PA) cross sections between picosecond and femtosecond excitation. This new approach takes into account excited-state absorption and stimulated emission of the molecules studied. The two-photon absorption cross-section spectra of a series of six fluorene-based derivatives, determined using picosecond pulses, over a broad spectral range (500-900 nm), and this approach using a modified fitting procedure in the open aperture Z-scan is reported. We demonstrate that the fluorene derivatives exhibit two-photon absorption cross-section values between 700 and 5000 GM, when excited into the two-photon allowed electronic state. Excitation anisotropy spectra, measured to investigate the nature of the observed linear and nonlinear absorption bands, are presented and provide insight into the 2PA process.

  3. Activation process and absorption/desorption of D2O for Zr-V-Fe getter

    NASA Astrophysics Data System (ADS)

    Ichimura, K.; Inoue, N.; Ashida, K.; Watanabe, K.; Takeuchi, T.

    1984-12-01

    Nonevaporable getters have wide applicability for tritium handling systems. From this view point, the activation process of the Zr-V-Fe getter (St-707) and absorption/desorption of D2O on the getter surface were investigated, by means of XPS-SIMS and mass analyzed thermal desorption spectroscopy. XPS-SIMS measurements revealed that the getter surface exposed to air was covered with adsorbed H2O, CO and small amounts of hydrocarbons and that the getter components are oxidized. Upon heating of the getter above 500 °C, the adsorbed species disappeared from the surface, partly due to desorption and partly due to migration into the bulk. Consequently, metallic Zr and V appeared on the surface, whereas Fe disappeared. The surface composition was evaluated to be 87 at% Zr-13 at% V. After the activation, water (D2O ) was readily absorbed into the getter at 300 °C in the form of deuterium atoms. The absorption rate was proportional to the partial pressure of water, indicating that the rate determining step for the absorption is the dissociation of water molecules on the surface. The absorption rate constant was 0.009 and 0.24 cc/s/cm2 (net surface area) [or 1.5 and 39 cc/s/cm2 (projected area)] at 25 and 300°C, respectively. Only D2 was desorbed from the getter exposed to D2O at 25 and 300 °C. The rate determining step for the desorption is association of deuterium atoms on the surface diffused from the bulk.

  4. Marangoni effect on the process of steam absorption into falling film of an aqueous solution of LiBr

    SciTech Connect

    Kashiwagi, Takao . Dept. of Mechanical Systems Engineering); Rie, Dongho . Dept. of Industrial Safety Engineering); Nomura, Tomohiro . Dept. of Mechanical Engineering); Omata, Koji ); Kurosawa, Shigekichi

    1994-03-01

    In most commercial machines, absorption enhancement has been done by adding small various kinds of surfactants, thereby reducing the surface tension of the absorbent solution and generating Marangoni convection near the solution surface during the refrigerant vapor-absorption process. This paper clarifies the most effective conditions of surfactant addition for absorption enhancement in the process of refrigerant vapor absorption into a vertical falling absorbent film. H[sub 2]O/LiBr and n-octanol were used as the refrigerant/absorbent combination and additive. Experiments were carried out by using an LiBr aqueous solution with and without n-octanol dissolution. Moreover, n-octanol vapor was supplied to the absorber in order to clarify the effect of an additive on absorption enhancement. The results of these experiments reveal that the presence of dropwise n-octanol in the surface of the absorbent falling film contributed significantly to the generation of violent and irregular Marangoni convection.

  5. X-ray Absorption Spectroscopy Characterization of Electrochemical Processes in Renewable Energy Storage and Conversion Devices

    SciTech Connect

    Farmand, Maryam

    2013-05-19

    The development of better energy conversion and storage devices, such as fuel cells and batteries, is crucial for reduction of our global carbon footprint and improving the quality of the air we breathe. However, both of these technologies face important challenges. The development of lower cost and better electrode materials, which are more durable and allow more control over the electrochemical reactions occurring at the electrode/electrolyte interface, is perhaps most important for meeting these challenges. Hence, full characterization of the electrochemical processes that occur at the electrodes is vital for intelligent design of more energy efficient electrodes. X-ray absorption spectroscopy (XAS) is a short-range order, element specific technique that can be utilized to probe the processes occurring at operating electrode surfaces, as well for studying the amorphous materials and nano-particles making up the electrodes. It has been increasingly used in recent years to study fuel cell catalysts through application of the and #916; and mgr; XANES technique, in combination with the more traditional X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) techniques. The and #916; and mgr; XANES data analysis technique, previously developed and applied to heterogeneous catalysts and fuel cell electrocatalysts by the GWU group, was extended in this work to provide for the first time space resolved adsorbate coverages on both electrodes of a direct methanol fuel cell. Even more importantly, the and #916; and mgr; technique was applied for the first time to battery relevant materials, where bulk properties such as the oxidation state and local geometry of a cathode are followed.

  6. Maintenance Resource Prediction in the Facility Life-Cycle Process

    DTIC Science & Technology

    1991-05-01

    life - cycle : planning, design, operation/maintenance, and demolition. In the past, estimates that involved maintenance resources have been inaccurate due to the lack of a comprehensive data base containing maintenance costs. To improve this accuracy, the U.S. Army Construction Engineering Research Laboratory (USACERL) has developed a series of maintenance resources data bases which can be used in economic analysis. In addition, models have been devised for prediction of outyear maintenance costs. Computer programs have been developed to automate the data bases and

  7. Flow pattern and mass transfer characteristics of valve tray in absorption process

    NASA Astrophysics Data System (ADS)

    Nurkhamidah, Siti; Altway, Ali; Wulansari, Ayu Savitri; Khanifah, Evi Fitriyah

    2015-12-01

    The flow pattern characteristics of valve tray in absorption process which is expressed in pressure drop and the number of equivalent tank in series (N) has an important role to know the efficiency and performance of a process. This study has been done in the absorption column by using water and air as liquid and gas phase, respectively. To observe pressure drop and flow pattern in the column, flow rate of liquid and air has been variated. Flow pattern has been determined by using pulse method and using NaCl as tracer. The experiment results show that the column pressure drop is mainly influenced by the liquid height on the tray. When the water flow rate is high, liquid height on the tray is higher so that the column pressure drops increases. Flow pattern characteristic of fluid on valve tray is affected by water and air flowrates. For high water flow rate, the residence time distribution (RTD) curve is sharper and the number of N is greater and the flow pattern tends to a plug flow. However, the number of N decreases when the air flowrate increases. The liquid-side mass transfer coefficient (kLa') is shown by the following empirical relationship kLa' = 2,607QL0,202Qv0,456.

  8. Process improvement by cycle time reduction through Lean Methodology

    NASA Astrophysics Data System (ADS)

    Siva, R.; patan, Mahamed naveed khan; lakshmi pavan kumar, Mane; Purusothaman, M.; pitchai, S. Antony; Jegathish, Y.

    2017-05-01

    In present world, every customer needs their products to get on time with good quality. Presently every industry is striving to satisfy their customer requirements. An aviation concern trying to accomplish continuous improvement in all its projects. In this project the maintenance service for the customer is analyzed. The maintenance part service is split up into four levels. Out of it, three levels are done in service shops and the fourth level falls under customer’s privilege to change the parts in their aircraft engines at their location. An enhancement for electronics initial provisioning (eIP) is done for fourth level. Customers request service shops to get their requirements through Recommended Spare Parts List (RSPL) by eIP. To complete this RSPL for one customer, it takes 61.5 hours as a cycle time which is very high. By mapping current state VSM and takt time, future state improvement can be done in order to reduce cycle time using Lean tools such as Poke-Yoke, Jidoka, 5S, Muda etc.,

  9. The carbon cycle and associated redox processes through time

    PubMed Central

    Hayes, John M; Waldbauer, Jacob R

    2006-01-01

    Earth's biogeochemical cycle of carbon delivers both limestones and organic materials to the crust. In numerous, biologically catalysed redox reactions, hydrogen, sulphur, iron, and oxygen serve prominently as electron donors and acceptors. The progress of these reactions can be reconstructed from records of variations in the abundance of 13C in sedimentary carbonate minerals and organic materials. Because the crust is always receiving new CO2 from the mantle and a portion of it is being reduced by photoautotrophs, the carbon cycle has continuously released oxidizing power. Most of it is represented by Fe3+ that has accumulated in the crust or been returned to the mantle via subduction. Less than 3% of the estimated, integrated production of oxidizing power since 3.8 Gyr ago is represented by O2 in the atmosphere and dissolved in seawater. The balance is represented by sulphate. The accumulation of oxidizing power can be estimated from budgets summarizing inputs of mantle carbon and rates of organic-carbon burial, but levels of O2 are only weakly and indirectly coupled to those phenomena and thus to carbon-isotopic records. Elevated abundances of 13C in carbonate minerals ca 2.3 Gyr old, in particular, are here interpreted as indicating the importance of methanogenic bacteria in sediments rather than increased burial of organic carbon. PMID:16754608

  10. Identification and quantification of nitrogen cycling processes in cryptogamic covers

    NASA Astrophysics Data System (ADS)

    Weber, Bettina; Wu, Dianming; Lenhart, Katharina; Tamm, Alexandra; Ruckteschler, Nina; Rodríguez-Caballero, Emilio; Elbert, Wolfgang; Burrows, Susannah; Clough, Tim; Steinkamp, Jörg; Meusel, Hannah; Behrendt, Thomas; Büdel, Burkhard; Andreae, Meinrat O.; Sörgel, Matthias; Cheng, Yafang; Crutzen, Paul; Keppler, Frank; Su, Hang; Pöschl, Ulrich

    2016-04-01

    Cryptogamic covers (CC) comprise communities of photoautotrophic cyanobacteria, lichens, algae, and bryophytes together with heterotrophic bacteria, microfungi, and archaea in varying proportions. Depending on their habitat, cryptogamic rock covers, cryptogamic plant covers, and cryptogamic soil covers are distinguished. The latter comprise biological soil crusts (biocrusts), which globally occur under dryland conditions. In a first assessment of their global role, we quantified that CC fix ˜49 Tg of nitrogen (N) per year (Elbert et al., 2013), corresponding to ˜1/2 of the maximum terrestrial biological N fixation determined in the latest IPCC report. The fixed N is used for biomass formation and partially leached into the ground, where it can be taken up by plants or transformed into N oxides, being emitted into the atmosphere. We show that biocrusts release nitric oxide (NO) and nitrous acid (HONO), which are key species in the global cycling of nitrogen and in the production of ozone and hydroxyl radicals, regulating the oxidizing power and self-cleaning capacity of the atmosphere. Based on laboratory, field and satellite measurement data, we obtained a best estimate of 1.1 Tg a-1 of NO-N and 0.6 Tg a-1 of HONO-N being globally emitted by biocrusts, corresponding to ˜20% of the global nitrogen oxide emissions from soils under natural vegetation (Weber et al., 2015). During full wetting and drying cycles, emissions peaked at low water contents suggesting NO- and HONO-formation under aerobic conditions during nitrification. Other measurements revealed that cryptogamic organisms release nitrous oxide (N2O), a greenhouse gas of crucial importance for climate change. The emission rates varied with temperature, humidity, and N deposition, but divided by respiratory CO2 emission they formed an almost constant ratio, which allowed upscaling on the global scale. We estimated annual N2O emissions of 0.3 - 0.6 Tg by cryptogams, accounting for 4-9% of the global N2O

  11. Absorption heat pump system

    DOEpatents

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  12. Exhaust gas monitoring based on absorption spectroscopy in the process industry

    NASA Astrophysics Data System (ADS)

    Zhang, Shuai; Liu, Wen-qing; Zhang, Yu-jun; Shu, Xiao-wen; Kan, Rui-feng; Cui, Yi-ben; He, Ying; Xu, Zhen-yu; Geng, Hui; Liu, Jian-guo

    2009-07-01

    This non-invasive gas monitor for exhaust gas monitoring must has high reliability and requires little maintenance. Monitor for in-situ measurements using tunable diode laser absorption spectroscopy (TDLAS) in the near infrared, can meet these requirements. TDLAS has evolved over the past decade from a laboratory especially to an accepted, robust and reliable technology for trace gas sensing. With the features of tunability and narrow linewidth of the distributed feedback (DFB) diode laser and by precisely tuning the laser output wavelength to a single isolated absorption line of the gas, TDLAS technique can be utilized to measure gas concentration with high sensitivity. Typical applications for monitoring of H2S, NH3, HC1 and HF are described here together by wavelength modulation spectroscopy with second-harmonic(WMS-2F) detection. This paper will illustrate the problems related to on-line applications, in particular, the overfall effects, automatic light intensity correction, temperature correction, which impacted on absorption coefficient and give details of how effect of automatic correction is necessary. The system mainly includes optics and electronics, optical system mainly composed of fiber, fiber coupler and beam expander, the electron part has been placed in safe analysis room not together with the optical part. Laser merely passes through one-meter-long pipes by the fiber coupling technology, so the system itself has anti-explosion. The results of the system are also presented in the end, the system's response time is only 0.5s, and can be achieved below 1×10-5 the detection limit at the volume fraction, it can entirely replace the traditional methods of detection exhaust gas in the process industry.

  13. Cycles in finite samples and cumulative processes of higher orders

    NASA Astrophysics Data System (ADS)

    Klemeš, VíT.; Klemeš, Ivo

    1988-01-01

    The process formed by a sequence of cumulative departures from the mean or from some other constant (residual mass curve, cusum chart) is a popular tool for the representation and analysis of time series in many sciences, for example, in hydrology, climatology, economics, game theory. In these and other natural and social sciences, similar cumulative processes also often arise naturally; examples include fluctuations of storage in a dam with a constant release rate, lake levels, volume of glaciers, biomass, inventories, and bank accounts. Moreover, many natural economic and other phenomena may represent, or contain, components of cumulative processes of higher orders, i.e., cumulative processes of cumulative processes. In this paper we show that for a sample {yt(0)}≡{xt} of any finite size N, the pure cumulative process of nth order, yt(n)≡∑i=1t(yi(n-1) - μ(n-1)), where μ(n-1) is the sample mean of {yt(n-1)} and t=1, 2, …, N, converges for n→∞ to a sine wave with a period equal to an integral fraction of the sample size N. This happens for any initial sample {yt(0)} and the convergence is of an exponential order. For samples from most stochastic as well as deterministic processes, the period of the limiting sine wave is equal to the sample size N. This behavior is demonstrated by examples involving samples from various processes ranging from pure random series to various deterministic series and including time series of some natural processes such as streamflow, lake levels, and glacier volumes. The paper includes a demonstration of effects of noise superimposed on, and of error in the value of, sample mean on the rate of convergence, and a discussion of some practical implications of the phenomenon described; it brings together some aspects of the work of Slutzky (1937), Hurst (1951), and Yule (1926).

  14. 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.

  15. Linking the Wilson Cycle to deep Earth processes (Invited)

    NASA Astrophysics Data System (ADS)

    Torsvik, T. H.; Burke, K. C.

    2010-12-01

    Over the past century description of the movement and deformation of the Earth's outer layer has evolved from the hypothesis of Continental Drift into Sea-Floor Spreading and thence to the theory of Plate Tectonics. This theory is as fundamentally unifying to the Earth Sciences as Darwin's Evolution Theory is to Life Science. By 1968 Tuzo Wilson had identified three basic elements of geodynamics: plate tectonics, mantle plumes of deep origin and the Wilson cycle of ocean opening and closing, which provides evidence of plate tectonic behavior in times before quantifiable plate rotations. We have recently shown that deep-seated plumes of the past have risen only from narrow plume generation zones (PGZs) at the Core Mantle Boundary and mostly on the edges of two Large Low Shear wave Velocity Provinces (LLSVPs) that have been stable, antipodal and equatorial in their present positions for hundreds of millions of years and perhaps for much longer. Even though links between mantle activity and plate tectonics are becoming more evident, notably through subsurface tomographic images, advances in mineral physics and much improved absolute plate motion reference frames, a need now is to generate a new Earth model embodying plate tectonics, shallow and deep mantle convection, including such elements as deeply subducted slabs and stable LLSVPs with plumes that rise only from PGZs on the CMB.

  16. 78 FR 47012 - Developing Software Life Cycle Processes Used in Safety Systems of Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ....'' This RG endorses the Institute of Electrical and Electronic Engineers (IEEE) Standard (Std.) 1074-2006, ``IEEE Standard for Developing a Software Project Life Cycle Process,'' issued 2006, with the... guidance in IEEE Std. 1074- 2006, ``IEEE Standard for Developing a Software Project Life Cycle...

  17. The Iterative Research Cycle: Process-Based Model Evaluation

    NASA Astrophysics Data System (ADS)

    Vrugt, J. A.

    2014-12-01

    The ever increasing pace of computational power, along with continued advances in measurement technologies and improvements in process understanding has stimulated the development of increasingly complex physics based models that simulate a myriad of processes at different spatial and temporal scales. Reconciling these high-order system models with perpetually larger volumes of field data is becoming more and more difficult, particularly because classical likelihood-based fitting methods lack the power to detect and pinpoint deficiencies in the model structure. In this talk I will give an overview of our latest research on process-based model calibration and evaluation. This approach, rooted in Bayesian theory, uses summary metrics of the calibration data rather than the data itself to help detect which component(s) of the model is (are) malfunctioning and in need of improvement. A few case studies involving hydrologic and geophysical models will be used to demonstrate the proposed methodology.

  18. A Remote Absorption Process for Disposal of Evaporate and Reverse Osmosis Concentrates

    SciTech Connect

    Brunsell, D.A.

    2008-07-01

    100% scalable from a concentrate test sample as small as 50 grams to full-scale processing of 100 cubic foot containers or larger. In summary: The absorption process offers utilities a viable and less costly alternative to on-site drying or solidification of concentrates. The absorption process can be completed by site personnel or by a vendor as a turnkey service. The process is suitable for multiple types of waste, including RO and evaporator concentrates, sludges, and other difficult to process waters and wet solids. (author)

  19. A Biophysicochemical Model for NO Removal by the Chemical Absorption-Biological Reduction Integrated Process.

    PubMed

    Zhao, Jingkai; Xia, Yinfeng; Li, Meifang; Li, Sujing; Li, Wei; Zhang, Shihan

    2016-08-16

    The chemical absorption-biological reduction (CABR) integrated process is regarded as a promising technology for NOx removal from flue gas. To advance the scale-up of the CABR process, a mathematic model based on mass transfer with reaction in the gas, liquid, and biofilm was developed to simulate and predict the NOx removal by the CABR system in a biotrickling filter. The developed model was validated by the experimental results and subsequently was used to predict the system performance under different operating conditions, such as NO and O2 concentration and gas and liquid flow rate. NO distribution in the gas phase along the biotrickling filter was also modeled and predicted. On the basis of the modeling results, the liquid flow rate and total iron concentration were optimized to achieve >90% NO removal efficiency. Furthermore, sensitivity analysis of the model revealed that the performance of the CABR process was controlled by the bioreduction activity of Fe(III)EDTA. This work will provide the guideline for the design and operation of the CABR process in the industrial application.

  20. Assessment of toxic metals in raw and processed milk samples using electrothermal atomic absorption spectrophotometer.

    PubMed

    Kazi, Tasneem Gul; Jalbani, Nusrat; Baig, Jameel Ahmed; Kandhro, Ghulam Abbas; Afridi, Hassan Imran; Arain, Mohammad Balal; Jamali, Mohammad Khan; Shah, Abdul Qadir

    2009-09-01

    Milk and dairy products have been recognized all over the world for their beneficial influence on human health. The levels of toxic metals (TMs) are an important component of safety and quality of milk. A simple and efficient microwave assisted extraction (MAE) method has been developed for the determination of TMs (Al, Cd, Ni and Pb), in raw and processed milk samples. A Plackett-Burman experimental design and 2(3)+star central composite design, were applied in order to determine the optimum conditions for MAE. Concentrations of TMs were measured by electrothermal atomic absorption spectrometry. The accuracy of the optimized procedure was evaluated by standard addition method and conventional wet acid digestion method (CDM), for comparative purpose. No significant differences were observed (P>0.05), when comparing the values obtained by the proposed MAE method and CDM (paired t-test). The average relative standard deviation of the MAE method varied between 4.3% and 7.6% based on analyte (n=6). The proposed method was successfully applied for the determination of understudy TMs in milk samples. The results of raw and processed milk indicated that environmental conditions and manufacturing processes play a key role in the distribution of toxic metals in raw and processed milk.

  1. Sound absorption of metallic sound absorbers fabricated via the selective laser melting process

    NASA Astrophysics Data System (ADS)

    Cheng, Li-Wei; Cheng, Chung-Wei; Chung, Kuo-Chun; Kam, Tai-Yan

    2017-01-01

    The sound absorption capability of metallic sound absorbers fabricated using the additive manufacturing (selective laser melting) method is investigated via both the experimental and theoretical approaches. The metallic sound absorption structures composed of periodic cubic cells were made of laser-melted Ti6Al4 V powder. The acoustic impedance equations with different frequency-independent and frequency-dependent end corrections factors are employed to calculate the theoretical sound absorption coefficients of the metallic sound absorption structures. The calculated sound absorption coefficients are in close agreement with the experimental results for the frequencies ranging from 2 to 13 kHz.

  2. Wavelet transform based on the optimal wavelet pairs for tunable diode laser absorption spectroscopy signal processing.

    PubMed

    Li, Jingsong; Yu, Benli; Fischer, Horst

    2015-04-01

    This paper presents a novel methodology-based discrete wavelet transform (DWT) and the choice of the optimal wavelet pairs to adaptively process tunable diode laser absorption spectroscopy (TDLAS) spectra for quantitative analysis, such as molecular spectroscopy and trace gas detection. The proposed methodology aims to construct an optimal calibration model for a TDLAS spectrum, regardless of its background structural characteristics, thus facilitating the application of TDLAS as a powerful tool for analytical chemistry. The performance of the proposed method is verified using analysis of both synthetic and observed signals, characterized with different noise levels and baseline drift. In terms of fitting precision and signal-to-noise ratio, both have been improved significantly using the proposed method.

  3. Processing bronchial sonograms to detect respiratory cycle fragments

    NASA Astrophysics Data System (ADS)

    Bureev, A. Sh; Zhdanov, D. S.; Zemlyakov, I. Yu; Svetlik, M. V.

    2014-10-01

    This article describes the authors' results of work on the development of a method for the automated assessment of the state of the human bronchopulmonary system based on acoustic data. In particular, the article covers the method of detecting breath sounds on bronchial sonograms obtained during the auscultation process.

  4. Cycles and Oscillations in Text Processing. No. 62.

    ERIC Educational Resources Information Center

    Bierschenk, Bernhard

    Classical research operations in the cognitive sciences concern categorizations as well as classifications, and have been strongly influenced by nomological approaches. As a consequence, information processing has been explained with reference to syntactic-semantic models. Because of an absence of structural implications, personal interpretations…

  5. Comparison of nonlinear absorption and carrier recombination times in GaAs grown by hydride vapor phase epitaxy and Bridgman processes

    NASA Astrophysics Data System (ADS)

    Gonzalez, Leonel P.; Murray, Joel; Carpenter, Amelia; Upchurch, Derek; Barnes, Jacob O.; Schunemann, Peter G.; Zawilski, Kevin; Guha, Shekhar

    2010-02-01

    μA 760 μm thick GaAs crystal was grown using HVPE. Transmission spectrum of this sample showed minimal absorption for light having photon energy below the bandgap energy, indicating the absence of the EL2 defects commonly found in Bridgman grown samples. Irradiance dependent absorption measured at 1.535 μm using 100 ns duration laser pulses showed increased nonlinear absorption in the HVPE grown GaAs compared to Bridgman grown samples. The dominant nonlinear absorption process in both samples was absorption due to free carriers generated by two-photon absorption. The HVPE grown sample showed higher nonlinear absorption due to longer carrier lifetimes.

  6. Secure Software Development Life Cycle Processes: A Technology Scouting Report

    DTIC Science & Technology

    2005-12-01

    through a CC evaluation: a Protection Profile ( PP ) and a Security Target (ST). Both documents must be created based on specific templates provided in the...implementation-dependent statement of security needs for a specific product. The PPs and the ST allow the following process for evaluation: 1. An organization...that wants to acquire or develop a particular type of security product defines their security needs using a PP . The organization then has the PP

  7. Zinc Absorption from Milk Is Affected by Dilution but Not by Thermal Processing, and Milk Enhances Absorption of Zinc from High-Phytate Rice in Young Dutch Women.

    PubMed

    Talsma, Elise F; Moretti, Diego; Ly, Sou Chheng; Dekkers, Renske; van den Heuvel, Ellen Ghm; Fitri, Aditia; Boelsma, Esther; Stomph, Tjeerd Jan; Zeder, Christophe; Melse-Boonstra, Alida

    2017-06-01

    Background: Milk has been suggested to increase zinc absorption. The effect of processing and the ability of milk to enhance zinc absorption from other foods has not been measured directly in humans.Objective: We aimed to assess zinc absorption from 1) milk undergoing various processing and preparatory steps and 2) from intrinsically labeled high-phytate rice consumed with milk or water.Methods: Two randomized crossover studies were conducted in healthy young women [age:18-25 y; body mass index (in kg/m(2)): 20-25]: 1) a milk study (n = 19) comparing the consumption of 800 mL full-fat ultra-high temperature (UHT) milk [heat-treated milk (HTM)], full-fat UHT milk diluted 1:1 with water [heat-treated milk and water (MW)], water, or unprocessed (raw) milk (UM), each extrinsically labeled with (67)Zn, and 2) a rice study (n = 18) comparing the consumption of 90 g intrinsically (67)Zn-labeled rice with 600 mL of water [rice and water (RW)] or full-fat UHT milk [rice and milk (RM)]. The fractional absorption of zinc (FAZ) was measured with the double-isotope tracer ratio method. In vitro, we assessed zinc extraction from rice blended into water, UM, or HTM with or without phytate.Results: FAZ from HTM was 25.5% (95% CI: 21.6%, 29.4%) and was not different from UM (27.8%; 95% CI: 24.2%, 31.4%). FAZ from water was higher (72.3%; 95% CI: 68.7%, 75.9%), whereas FAZ from MW was lower (19.7%; 95% CI: 17.5%, 21.9%) than HTM and UM (both P < 0.01). FAZ from RM (20.7%; 95% CI: 18.8%, 22.7%) was significantly higher than from RW (12.8%; 95% CI: 10.8%, 14.6%; P < 0.01). In vitro, HTM and UM showed several orders of magnitude higher extraction of zinc from rice with HTM than from rice with water at various phytate concentrations.Conclusions: Milk enhanced human FAZ from high-phytate rice by 62% compared with water. Diluting milk with water decreases its absorption-enhancing proprieties, whereas UHT processing does not. This trial was registered at the Dutch trial registry as NTR4267

  8. [Woman's participation in the decision process of the pregnancy and puerperal cycle: nursing care integrative review].

    PubMed

    Busanello, Josefine; Lunardi Filho, Wilson Danilo; Kerber, Nalú Pereira da Costa; Lunardi, Valéria Lerch; dos Santos, Silvana Sidnei

    2011-12-01

    This is an integrative review that aims to identify the contribution of nursing care for woman's participation in the decision process of the pregnancy and puerperal cycle, as described in Brazilian scientific publications. The scientific productions were retrieved in May, 2010, from the Virtual Library of Health (Biblioteca Virtual em Saúde) database. From the eight articles reviewed, two themes stood out: Contributions of nursing care to the woman's participation in the decision process of the pregnancy and puerperal cycle; and Limitations of nursing care to the woman's participation in the decision process of the pregnancy and puerperal cycle. The following review supports the production of knowledge in nursing, by identifying a gap in what nurses know and do about this issue, as shown by the lack of nursing researches that concern, specifically, the participation of the woman in the decision process during the pregnancy and puerperal cycle and the possible contributions of nursing care to ensure women of this right.

  9. Afferent electrical stimulation during cycling improves spinal processing of sensorimotor function after incomplete spinal cord injury.

    PubMed

    Piazza, Stefano; Serrano-Muñoz, Diego; Gómez-Soriano, Julio; Torricelli, Diego; Segura-Fragosa, Antonio; Pons, José Luis; Taylor, Julian

    2017-01-01

    Appropriate afferent feedback delivery during the execution of motor tasks is important for rehabilitation after incomplete spinal cord injury (iSCI). However, during leg-cycling therapy, the plantar afferent feedback is minimal. We hypothesize that the augmentation of sensory input by combining cycling with a locomotor-like stimulation of plantar cutaneous innervations (ES-cycling), might help to restore proper spinal processing of sensorimotor function. Thirteen non-injured subjects and 10 subjects with iSCI performed 10 minutes of cycling and, on another session, of ES-cycling. To assess spinal processing of sensorimotor function, soleus H-reflex response was tested following a conditioning plantar electrical stimulation applied at 25-100 ms inter-stimulus intervals (ISI's), measured before and after the execution of the tasks. Before tasks execution, the conditioned H-reflex response was modulated in non-injured subjects, and absent in subjects with iSCI; after cycling, modulation profiles were unchanged. However, after ES-cycling a significant increase in H-reflex excitability was observed in the non-injured group at 100 ms ISI (p < 0.05), and in the iSCI group between 50-75 ms ISI (p < 0.001). The loss of reflex modulation in subjects with iSCI suggests reduced spinal processing of sensorimotor function. Reflex modulation recovery after ES-cycling may indicate the partial reactivation of these mechanisms.

  10. Design, evaluation and recommedation effort relating to the modification of a residential 3-ton absorption cycle cooling unit for operation with solar energy

    NASA Technical Reports Server (NTRS)

    Merrick, R. H.; Anderson, P. P.

    1973-01-01

    The possible use of solar energy powered absorption units to provide cooling and heating of residential buildings is studied. Both, the ammonia-water and the water-lithium bromide cycles, are considered. It is shown that the air cooled ammonia water unit does not meet the criteria for COP and pump power on the cooling cycle and the heat obtained from it acting as a heat pump is at too low a temperature. If the ammonia machine is water cooled it will meet the design criteria for cooling but can not supply the heating needs. The water cooled lithium bromide unit meets the specified performance for cooling with appreciably lower generator temperatures and without a mechanical solution pump. It is recommeded that in the demonstration project a direct expansion lithium bromide unit be used for cooling and an auxiliary duct coil using the solar heated water be employed for heating.

  11. Hybrid Membrane/Absorption Process for Post-combustion CO2 Capture

    SciTech Connect

    Li, Shiguang; Shou, S.; Pyrzynski, Travis; Makkuni, Ajay; Meyer, Howard

    2013-12-31

    This report summarizes scientific/technical progress made for bench-scale membrane contactor technology for post-combustion CO2 capture from DOE Contract No. DE-FE-0004787. Budget Period 1 (BP1) membrane absorber, Budget Period 2 (BP2) membrane desorber and Budget Period 3 (BP3) integrated system and field testing studies have been completed successfully and met or exceeded the technical targets (≥ 90% CO2 removal and CO2 purity of 97% in one membrane stage). Significant breakthroughs are summarized below: BP1 research: The feasibility of utilizing the poly (ether ether ketone), PEEK, based hollow fiber contractor (HFC) in combination with chemical solvents to separate and capture at least 90% of the CO2 from simulated flue gases has been successfully established. Excellent progress has been made as we have achieved the BP1 goal: ≥ 1,000 membrane intrinsic CO2 permeance, ≥ 90% CO2 removal in one stage, ≤ 2 psi gas side pressure drop, and ≥ 1 (sec)-1 mass transfer coefficient. Initial test results also show that the CO2 capture performance, using activated Methyl Diethanol Amine (aMDEA) solvent, was not affected by flue gas contaminants O2 (~3%), NO2 (66 ppmv), and SO2 (145 ppmv). BP2 research: The feasibility of utilizing the PEEK HFC for CO2-loaded solvent regeneration has been successfully established High CO2 stripping flux, one order of magnitude higher than CO2 absorption flux, have been achieved. Refined economic evaluation based on BP1 membrane absorber and BP2 membrane desorber laboratory test data indicate that the CO2 capture costs are 36% lower than DOE’s benchmark amine absorption technology. BP3 research: A bench-scale system utilizing a membrane absorber and desorber was integrated into a continuous CO2 capture process using contactors containing 10 to 20 ft2 of membrane area. The integrated process operation was stable through a 100-hour laboratory test, utilizing a simulated flue gas stream. Greater than 90% CO2 capture combined with 97

  12. The arctic seasonal cycle of total column CO2 and CH4 from ground-based solar and lunar FTIR absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Buschmann, Matthias; Deutscher, Nicholas M.; Palm, Mathias; Warneke, Thorsten; Weinzierl, Christine; Notholt, Justus

    2017-07-01

    Solar absorption spectroscopy in the near infrared has been performed in Ny-Ålesund (78.9° N, 11.9° E) since 2002; however, due to the high latitude of the site, the sun is below the horizon from October to March (polar night) and no solar absorption measurements are possible. Here we present a novel method of retrieving the total column dry-air mole fractions (DMFs) of CO2 and CH4 using moonlight in winter. Measurements have been taken during the polar nights from 2012 to 2016 and are validated with TCCON (Total Carbon Column Observing Network) measurements by solar and lunar absorption measurements on consecutive days and nights during spring and autumn. The complete seasonal cycle of the DMFs of CO2 and CH4 is presented and a precision of up to 0.5 % is achieved. A comparison of solar and lunar measurements on consecutive days during day and night in March 2013 yields non-significant biases of 0. 66 ± 4. 56 ppm for xCO2 and -1. 94 ± 20. 63 ppb for xCH4. Additionally a model comparison has been performed with data from various reanalysis models.

  13. Evaluation of an Absorption Heat Pump to Mitigate Plant Capacity Reduction Due to Ambient Temperature Rise for an Air-Cooled Ammonia and Water Cycle: Preprint

    SciTech Connect

    Bharathan, D.; Nix, G.

    2001-08-06

    Air-cooled geothermal plants suffer substantial decreases in generating capacity at increased ambient temperatures. As the ambient temperature rises by 50 F above a design value of 50 F, at low brine-resource temperatures, the decrease in generating capacity can be more than 50%. This decrease is caused primarily by increased condenser pressure. Using mixed-working fluids has recently drawn considerable attention for use in power cycles. Such cycles are more readily amenable to use of absorption ''heat pumps.'' For a system that uses ammonia and water as the mixed-working fluid, this paper evaluates using an absorption heat pump to reduce condenser backpressure. At high ambient temperatures, part of the turbine exhaust vapor is absorbed into a circulating mixed stream in an absorber in series with the main condenser. This steam is pumped up to a higher pressure and heated to strip the excess vapor, which is recondensed using an additional air-cooled condenser. The operating conditions are chosen to reconstitute this condensate back to the same concentration as drawn from the original system. We analyzed two power plants of nominal 1-megawatt capacity. The design resource temperatures were 250 F and 300 F. Ambient temperature was allowed to rise from a design value of 50 F to 100 F. The analyses indicate that using an absorption heat pump is feasible. For the 300 F resource, an increased brine flow of 30% resulted in a net power increase of 21%. For the 250 F resource, the increase was smaller. However, these results are highly plant- and equipment-specific because evaluations must be carried out at off-design conditions for the condenser. Such studies should be carried out for specific power plants that suffer most from increased ambient temperatures.

  14. Extended x-ray-absorption fine structure—Auger process for surface structure analysis: Theoretical considerations of a proposed experiment

    PubMed Central

    Landman, Uzi; Adams, David L.

    1976-01-01

    A method for surface structure analysis is proposed. The proposed process combines x-ray photoabsorption and Auger electron emission. The extended x-ray-absorption fine structure, occurring for photon energies above an atomic absorption edge, contains structural information of the microscopic environment due to the coupling of the photoelectron final state with the atomic initial state. Measurement of the variations in the intensity of particular Auger lines, as a function of the incident radiation energy, provides a surface sensitive measure of the photoabsorption cross section in the media. Theoretical considerations of the physical processes underlying the proposed experiment and its feasibility, and a discussion of background contributions are presented. PMID:16592339

  15. Synthesis and review: African environmental processes and water-cycle dynamics

    NASA Astrophysics Data System (ADS)

    Ichoku, Charles; Adegoke, Jimmy

    2016-12-01

    Africa’s vast landmass harbors a variety of physical processes that affect the environment and the water cycle. This focus issue on ‘African Environmental Processes and Water-Cycle Dynamics’ contains eight articles that address these phenomena from different but complementary perspectives. Fires used for agricultural and related purposes play a major role in land-cover change, surface albedo modifications, and smoke emission; all of which affect the environment and the water cycle in different ways. However, emissions of aerosols and trace gases are not restricted to fires, but also emanate from other natural and human activities. The African water cycle undergoes significant perturbations that are attributable to several factors, including the aforesaid environmental processes. These changes in the water cycle have produced severe drought and flooding events in recent decades that affect societal wellbeing across sub-Saharan Africa. The combined effects of the environmental processes and water-cycle dynamics affect and are affected by climate variability and can be propagated beyond the continent. Future studies should utilize the wealth of observations and modeling tools that are constantly improving to clearly elucidate the interrelationships between all of these phenomena for the benefit of society.

  16. Process for separating carbon dioxide from flue gas using sweep-based membrane separation and absorption steps

    DOEpatents

    Wijmans, Johannes G.; Baker, Richard W.; Merkel, Timothy C.

    2012-08-21

    A gas separation process for treating flue gases from combustion processes, and combustion processes including such gas separation. The invention involves routing a first portion of the flue gas stream to be treated to an absorption-based carbon dioxide capture step, while simultaneously flowing a second portion of the flue gas across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, then passing the permeate/sweep gas to the combustor.

  17. 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.

  18. Collisional Processing of Comet and Asteroid Surfaces: Velocity Effects on Absorption Spectra

    NASA Technical Reports Server (NTRS)

    Lederer, S. M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Smith, D. C.; Nakamura-Messenger, K.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

    2012-01-01

    A new paradigm has emerged where 3.9 Gyr ago, a violent reshuffling reshaped the placement of small bodies in the solar system (the Nice model). Surface properties of these objects may have been affected by collisions caused by this event, and by collisions with other small bodies since their emplacement. These impacts affect the spectrographic observations of these bodies today. Shock effects (e.g., planar dislocations) manifest in minerals allowing astronomers to better understand geophysical impact processing that has occurred on small bodies. At the Experimental Impact Laboratory at NASA Johnson Space Center, we have impacted forsterite and enstatite across a range of velocities. We find that the amount of spectral variation, absorption wavelength, and full width half maximum of the absorbance peaks vary non-linearly with the velocity of the impact. We also find that the spectral variation increases with decreasing crystal size (single solid rock versus granular). Future analyses include quantification of the spectral changes with different impactor densities, temperature, and additional impact velocities. Results on diopside, fayalite, and magnesite can be found in Lederer et al., this meeting.

  19. Collisional Processing Of Comet And Asteroid Surfaces: Velocity Effects On Absorption Spectra

    NASA Astrophysics Data System (ADS)

    Jensen, Elizabeth; Lederer, S. M.; Wooden, D. H.; Lindsay, S. S.; Nakamura-Messenger, K.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

    2012-10-01

    A new paradigm has emerged where 3.9 Gyr ago, a violent reshuffling reshaped the placement of small bodies in the solar system (the Nice model). Surface properties of these objects may have been affected by collisions caused by this event, and by collisions with other small bodies since their emplacement. These impacts affect the spectroscopic observations of these bodies today. Shock effects (e.g., planar dislocations) manifest in minerals allowing astronomers to better understand geophysical impact processing that has occurred on small bodies. At the Experimental Impact Laboratory at NASA Johnson Space Center, we have impacted forsterite and enstatite across a range of velocities. We find that the amount of spectral variation, absorption wavelength, and full width half maximum of the absorbance peaks vary non-linearly with the velocity of the impact. We also find that the spectral variation increases with decreasing crystal size (single solid rock versus granular). Future analyses include quantification of the spectral changes with different impactor densities, temperature, and additional impact velocities. Results on diopside, fayalite, and magnesite can be found in Lederer et al., this meeting. Funding was provided by the NASA PG&G grant 09-PGG09-0115, NSF grant AST-1010012, and a Cottrell College Scholarship through the Research Corporation.

  20. Organizational procedure for the study of pion production and absorption processes on nuclei

    SciTech Connect

    Banerjee, M.K.; Walker, G.E.

    1983-02-01

    For nuclear processes involving pions, such as pion production/absorption or exchange currents, it is shown that a natural organization involves adoption of the ..pi..NN vertex function g/sub ..pi../(q/sup 2/)..gamma../sub 5/tau/sub ..cap alpha../, where q is the pion four-momentum and g/sub ..pi../(m/sub ..pi../ /sup 2/)approx. =13.4 is the renormalized pion-nucleon coupling constant. The result is independent of the form and details of any fundamental interaction Lagrangian. The difference between g/sub ..pi../(q/sup 2/)..gamma../sub 5/tau/sub ..cap alpha../ and the fully-dressed ..pi..NN vertex function contributes to amplitudes involving more bosons, e.g., scattering amplitudes (..pi..N..--> pi..N), production amplitudes (..pi..N..--> pi pi..N), etc. Such contributions are mediated through either seagull-like terms or P11 intermediate states. It is pointed out that it is neither necessary nor practical to calculate these partial contributions to scattering and production amplitudes. One can always exploit other approaches, theoretical and phenomenological, to make reasonably good models for the full amplitudes. The usual procedure of including the effects of negative energy parts of the nucleon propagator in interaction potentials, exchange currents, etc., is easily included in the present organization. The result is that from scattering amplitudes, etc; the positive energy nucleon poles are deleted but Z graphs are included.

  1. Development And Optical Absorption Properties Of A Laser Induced Plasma During CO2-Laser Processing

    NASA Astrophysics Data System (ADS)

    Beyer, E.; Bakowsky, L.; Loosen, P.; Poprawe, R.; Herziger, G.

    1984-03-01

    Laser material processing is accompanied by a laser induced plasma in front of the target surface as soon as the laser radiation exceeds a certain critical intensity. For cw CO2-laser machining of metal targets the threshold for plasma onset is about 106 W/cm2. Critical condition for plasma generation at this intensity level is to reach evaporation temperature at the target's surface. At intensity levels exceeding 106 W/cm2 the laser light is interacting with the laser induced plasma and then the plasma in turn interacts with the target. The absorptivity is no longer constant, but increases with increasing intensity of the incident radiation, so that the total amount of power coupled to the target is increasing. This holds up to intensity levels of 2'10 Wicm2. Then the plasma begins to withdraw from the target surface, thus interrupting plasma-target interaction so that the laser power is no longer coupled into the target completely. The results of laser welding (welding depth) in the intensity level of 106 W/cm2 are governed by the product of incident intensity times focus radius, so that welding results are a measure to determine focus radius and laser intensity.

  2. Process sensitivity studies of the Westinghouse sulfur cycle for hydrogen generation

    NASA Technical Reports Server (NTRS)

    Carty, R. H.; Cox, K. E.; Funk, J. E.; Soliman, M. A.; Conger, W. L.; Brecher, L. E.; Spewock, S.

    1976-01-01

    The effect of variations of acid concentration, pressure, and temperature on the thermal process efficiency of the Westinghouse sulfur cycle was examined using the HYDRGN program. Modifications to the original program were made to duplicate the process flowsheet and take into account combined cycle heat-to-work efficiencies for electrochemical work requirements, aqueous solutions, and heat-of-mixing effects. A total of 125 process variations were considered (acid concentration: 50-90 w/o; pressure: 15-750 psia; temperature: 922K - 1366K). The methods of analysis, results, and conclusions are presented.

  3. Process sensitivity studies of the Westinghouse Sulfur Cycle for hydrogen generation

    NASA Technical Reports Server (NTRS)

    Carty, R.; Funk, J.; Soliman, M.; Conger, W.; Brecher, L.; Spewock, S.; Cox, K.

    1976-01-01

    The effect of variations of acid concentration, pressure, and temperature on the thermal process efficiency of the Westinghouse Sulfur Cycle was examined using the University of Kentucky's HYDRGN program. Modifications to the original program were made to duplicate the process flow sheet and take into account combined-cycle heat-to-work efficiencies for electrochemical work requirements, aqueous solutions, and heat-of-mixing effects. A total of 125 process variations were considered (acid concentration: 50-90 w/o; pressure: 15-750 psia; temperature: 922-1366 K (2000 F)). The methods of analysis, results, and conclusions are presented.

  4. Process sensitivity studies of the Westinghouse Sulfur Cycle for hydrogen generation

    NASA Technical Reports Server (NTRS)

    Carty, R.; Funk, J.; Soliman, M.; Conger, W.; Brecher, L.; Spewock, S.; Cox, K.

    1976-01-01

    The effect of variations of acid concentration, pressure, and temperature on the thermal process efficiency of the Westinghouse Sulfur Cycle was examined using the University of Kentucky's HYDRGN program. Modifications to the original program were made to duplicate the process flow sheet and take into account combined-cycle heat-to-work efficiencies for electrochemical work requirements, aqueous solutions, and heat-of-mixing effects. A total of 125 process variations were considered (acid concentration: 50-90 w/o; pressure: 15-750 psia; temperature: 922-1366 K (2000 F)). The methods of analysis, results, and conclusions are presented.

  5. An analysis of hydrogen production via closed-cycle schemes. [thermochemical processings from water

    NASA Technical Reports Server (NTRS)

    Chao, R. E.; Cox, K. E.

    1975-01-01

    A thermodynamic analysis and state-of-the-art review of three basic schemes for production of hydrogen from water: electrolysis, thermal water-splitting, and multi-step thermochemical closed cycles is presented. Criteria for work-saving thermochemical closed-cycle processes are established, and several schemes are reviewed in light of such criteria. An economic analysis is also presented in the context of energy costs.

  6. An analysis of hydrogen production via closed-cycle schemes. [thermochemical processings from water

    NASA Technical Reports Server (NTRS)

    Chao, R. E.; Cox, K. E.

    1975-01-01

    A thermodynamic analysis and state-of-the-art review of three basic schemes for production of hydrogen from water: electrolysis, thermal water-splitting, and multi-step thermochemical closed cycles is presented. Criteria for work-saving thermochemical closed-cycle processes are established, and several schemes are reviewed in light of such criteria. An economic analysis is also presented in the context of energy costs.

  7. Nitrogen cycling and water pulses in semiarid grasslands: Are microbial and plant processes temporarily asynchronous?

    USDA-ARS?s Scientific Manuscript database

    Precipitation pulses in arid ecosystems can lead to temporal asynchrony in microbial and plant processing of nitrogen (N) during drying/wetting cycles causing increased N loss. In contrast, more consistent availability of soil moisture in mesic ecosystems can synchronize microbial and plant processe...

  8. Krebs cycle intermediates regulate DNA and histone methylation: epigenetic impact on the aging process.

    PubMed

    Salminen, Antero; Kauppinen, Anu; Hiltunen, Mikko; Kaarniranta, Kai

    2014-07-01

    Many aging theories have proposed that mitochondria and energy metabolism have a major role in the aging process. There are recent studies indicating that Krebs cycle intermediates can shape the epigenetic landscape of chromatin by regulating DNA and histone methylation. A growing evidence indicates that epigenetics plays an important role in the regulation of healthspan but also is involved in the aging process. 2-Oxoglutarate (α-ketoglutarate) is a key metabolite in the Krebs cycle but it is also an obligatory substrate for 2-oxoglutarate-dependent dioxygenases (2-OGDO). The 2-OGDO enzyme family includes the major enzymes of DNA and histone demethylation, i.e. Ten-Eleven Translocation (TETs) and Jumonji C domain containing (JmjC) demethylases. In addition, 2-OGDO members can regulate collagen synthesis and hypoxic responses in a non-epigenetical manner. Interestingly, succinate and fumarate, also Krebs cycle intermediates, are potent inhibitors of 2-OGDO enzymes, i.e. the balance of Krebs cycle reactions can affect the level of DNA and histone methylation and thus control gene expression. We will review the epigenetic mechanisms through which Krebs cycle intermediates control the DNA and histone methylation. We propose that age-related disturbances in the Krebs cycle function induce stochastic epigenetic changes in chromatin structures which in turn promote the aging process. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Model reduction and physical understanding of slowly oscillating processes : the circadian cycle.

    SciTech Connect

    Goussis, Dimitris A.; Najm, Habib N.

    2006-01-01

    A differential system that models the circadian rhythm in Drosophila is analyzed with the computational singular perturbation (CSP) algorithm. Reduced nonstiff models of prespecified accuracy are constructed, the form and size of which are time-dependent. When compared with conventional asymptotic analysis, CSP exhibits superior performance in constructing reduced models, since it can algorithmically identify and apply all the required order of magnitude estimates and algebraic manipulations. A similar performance is demonstrated by CSP in generating data that allow for the acquisition of physical understanding. It is shown that the processes driving the circadian cycle are (i) mRNA translation into monomer protein, and monomer protein destruction by phosphorylation and degradation (along the largest portion of the cycle); and (ii) mRNA synthesis (along a short portion of the cycle). These are slow processes. Their action in driving the cycle is allowed by the equilibration of the fastest processes; (1) the monomer dimerization with the dimer dissociation (along the largest portion of the cycle); and (2) the net production of monomer+dimmer proteins with that of mRNA (along the short portion of the cycle). Additional results (regarding the time scales of the established equilibria, their origin, the rate limiting steps, the couplings among the variables, etc.) highlight the utility of CSP for automated identification of the important underlying dynamical features, otherwise accessible only for simple systems whose various suitable simplifications can easily be recognized.

  10. Influence of coupling of sorption and photosynthetic processes on trace element cycles in natural waters

    USGS Publications Warehouse

    Fuller, C.C.; Davis, J.A.

    1989-01-01

    Chemical and biological processes have important roles in the transport and cycling of trace elements in natural waters, but their complex interactions are often not well understood. Trace-element concentrations may, for example, be controlled by adsorption-desorption reactions at mineral surfaces, with the equilibrium strongly influenced by pH. Variations in pH due to photosynthetic activity should result in concentration fluctuations as the adsorption-desorption equilibrium shifts with pH. To investigate these interactions, we have studied the effect of diurnal cycling of pH on dissolved arsenate in a perennial stream contaminated with arsenic. As expected, a diurnal cycle in arsenate concentration was observed, but surprisingly, the arsenate cycle lags several hours behind the pH cycle. Laboratory experiments show that the lag results from a slow approach to sorption equilibrium. Our observations demonstrate that the coupling of photosynthesis and sorption processes may have an important influence on the cycling of many trace elements and emphasize the importance of understanding sorption kinetics in modelling these processes.

  11. Towards an improved understanding of processes controlling absorption efficiency and biomagnification of organic chemicals by fish.

    PubMed

    Xiao, Ruiyang; Arnot, Jon A; MacLeod, Matthew

    2015-11-01

    Dietary exposure is considered the dominant pathway for fish exposed to persistent, hydrophobic chemicals in the environment. Here we present a dynamic, fugacity-based three-compartment bioaccumulation model that describes the fish body as one compartment and the gastrointestinal tract (GIT) as two compartments. The model simulates uptake from the GIT by passive diffusion and micelle-mediated diffusion, and chemical degradation in the fish and the GIT compartments. We applied the model to a consistent measured dietary uptake and depuration dataset for rainbow trout (n=215) that is comprised of chlorinated benzenes, biphenyls, dioxins, diphenyl ethers, and polycyclic aromatic hydrocarbons (PAHs). Model performance relative to the measured data is statistically similar regardless of whether micelle-mediated diffusion is included; however, there are considerable uncertainties in modeling this process. When degradation in the GIT is assumed to be negligible, modeled chemical elimination rates are similar to measured rates; however, predicted concentrations of the PAHs are consistently higher than measurements by up to a factor of 20. Introducing a kinetic limit on chemical transport from the fish compartment to the GIT and increasing the rate constant for degradation of PAHs in tissues of the liver and/or GIT are required to achieve good agreement between the modelled and measured concentrations for PAHs. Our results indicate that the apparent low absorption efficiency of PAHs relative to the chemicals with similar hydrophobicity is attributable to biotransformation in the liver and/or the GIT. Our results provide process-level insights about controls on the extent of bioaccumulation of chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Phase Transfer-Catalyzed Fast CO2 Absorption by MgO-Based Absorbents with High Cycling Capacity

    SciTech Connect

    Zhang, Keling; Li, Xiaohong S.; Li, Weizhen; Rohatgi, Aashish; Duan, Yuhua; Singh, Prabhakar; Li, Liyu; King, David L.

    2014-06-01

    CO2 capture from pre-combustion syngas in the temperature range of 250-400°C is highly desirable from an energy efficiency perspective. Thermodynamically, MgO is a promising material for CO2 capture, but the gas-solid reaction to produce MgCO3 is kinetically slow due to high lattice energy. We report here fast CO2 absorption over a solid MgO-molten nitrate/nitrite aggregate through phase transfer catalysis, in which the molten phase serves as both a catalyst and reaction medium. Reaction with CO2 at the gas-solid-liquid triple phase boundary results in formation of MgCO3 with significant reaction rate and a high conversion of MgO. This methodology is also applicable to other alkaline earth oxides, inspiring the design of absorbents which require activation of the bulk material.

  13. Characterization of Photon-Counting Detector Responsivity for Non-Linear Two-Photon Absorption Process

    NASA Technical Reports Server (NTRS)

    Sburlan, S. E.; Farr, W. H.

    2011-01-01

    Sub-band absorption at 1550 nm has been demonstrated and characterized on silicon Geiger mode detectors which normally would be expected to have no response at this wavelength. We compare responsivity measurements to singlephoton absorption for wavelengths slightly above the bandgap wavelength of silicon (approx. 1100 microns). One application for this low efficiency sub-band absorption is in deep space optical communication systems where it is desirable to track a 1030 nm uplink beacon on the same flight terminal detector array that monitors a 1550 nm downlink signal for pointingcontrol. The currently observed absorption at 1550 nm provides 60-70 dB of isolation compared to the response at 1064 nm, which is desirable to avoid saturation of the detector by scattered light from the downlink laser.

  14. Stability and absorption of anthocyanins from blueberries subjected to a simulated digestion process.

    PubMed

    Liu, Yixiang; Zhang, Di; Wu, Yongpei; Wang, Dan; Wei, Ying; Wu, Jiulin; Ji, Baoping

    2014-06-01

    Numerous studies have shown that anthocyanins usually have better in vitro bioactivity than in vivo bioactivity. This may be due to physiochemical degradation during gastrointestinal digestion and their poor bioavailability in in vivo studies. Therefore, this study aims to investigate the effects of anthocyanin structure on their stability under simulated gastrointestinal digestion and to assess their absorption in the intestines using Caco-2 human intestinal cell monolayers. The results show that gastric digestion does not significant affect blueberry anthocyanins in terms of composition and antioxidative activity. However, approximately 42% of the total anthocyanin and 29% of the antioxidative activity were lost during intestinal digestion. Structural analysis indicated that fewer free hydroxyl groups and more methoxy groups in the B-ring improve anthocyanin stability. The absorption trials demonstrated that more hydrophobic anthocyanins have better absorption efficiency than more hydrophilic anthocyanins. Furthermore, the glycoside structure also determines the absorption efficiency of anthocyanins.

  15. Characterization of Photon-Counting Detector Responsivity for Non-Linear Two-Photon Absorption Process

    NASA Technical Reports Server (NTRS)

    Sburlan, S. E.; Farr, W. H.

    2011-01-01

    Sub-band absorption at 1550 nm has been demonstrated and characterized on silicon Geiger mode detectors which normally would be expected to have no response at this wavelength. We compare responsivity measurements to singlephoton absorption for wavelengths slightly above the bandgap wavelength of silicon (approx. 1100 microns). One application for this low efficiency sub-band absorption is in deep space optical communication systems where it is desirable to track a 1030 nm uplink beacon on the same flight terminal detector array that monitors a 1550 nm downlink signal for pointingcontrol. The currently observed absorption at 1550 nm provides 60-70 dB of isolation compared to the response at 1064 nm, which is desirable to avoid saturation of the detector by scattered light from the downlink laser.

  16. Enabling forbidden processes: quantum and solvation enhancement of nitrate anion UV absorption.

    PubMed

    Svoboda, Ondřej; Kubelová, Lucie; Slavíček, Petr

    2013-12-05

    We present simulated electronic absorption spectra of isolated and solvated nitrate anion in the UV region, focusing primarily on the absorption into the first absorption band around 300 nm. This weak absorption band in this spectral region is responsible for the generation of NOx in the polar areas or OH(•) radicals in the hydrosphere. The 300 nm absorption band is symmetrically strongly forbidden and coupling of at least two vibrational modes is needed to allow the transition in the isolated nitrate anion. Further symmetry breaking is provided by solvation. In this study we model the absorption spectra of nitrate-water clusters using the combined reflection principle path integral molecular dynamics (RP-PIMD) method. Condensed phase UV spectra are modeled within a cluster-continuum model. The calculated spectra are compared with experimental bulk phase measurements and reasonable agreement is found. We also provide a benchmarking of the DFT functionals to be used for a description of the electronically excited states of solvated nitrate anion.

  17. Carbonic anhydrase promotes the absorption rate of CO2 in post-combustion processes.

    PubMed

    Vinoba, Mari; Bhagiyalakshmi, Margandan; Grace, Andrews Nirmala; Kim, Dae Hoon; Yoon, Yeoil; Nam, Sung Chan; Baek, Il Hyun; Jeong, Soon Kwan

    2013-05-09

    The rate of carbon dioxide (CO2) absorption by monoethanol amine (MEA), diethanol amine (DEA), N-methyl-2,2'-iminodiethanol (MDEA), and 2-amino-2-methyl 1-propanol (AMP) solutions was found to be enhanced by the addition of bovine carbonic anhydrase (CA), has been investigated using a vapor-liquid equilibrium (VLE) device. The enthalpy (-ΔHabs) of CO2 absorption and the absorption capacities of aqueous amines were measured in the presence and/or absence of CA enzyme via differential reaction calorimeter (DRC). The reaction temperature (ΔT) under adiabatic conditions was determined based on the DRC analysis. Bicarbonate and carbamate species formation mechanisms were elucidated by (1)H and (13)C NMR spectral analysis. The overall CO2 absorption rate (flux) and rate constant (kapp) followed the order MEA > DEA > AMP > MDEA in the absence or presence of CA. Hydration of CO2 by MDEA in the presence of CA directly produced bicarbonate, whereas AMP produced unstable carbamate intermediate, then underwent hydrolytic reaction and converted to bicarbonate. The MDEA > AMP > DEA > MEA reverse ordering of the enhanced CO2 flux and kapp in the presence of CA was due to bicarbonate formation by the tertiary and sterically hindered amines. Thus, CA increased the rate of CO2 absorption by MDEA by a factor of 3 relative to the rate of absorption by MDEA alone. The thermal effects suggested that CA yielded a higher activity at 40 °C.

  18. Nonlinear optical properties of tetrapyrazinoporphyrazinato indium chloride complexes due to excited-state absorption processes.

    PubMed

    Dini, Danilo; Hanack, Michael; Meneghetti, Moreno

    2005-07-07

    The multiphoton absorption properties of the axially substituted tetrapyrazinotetraazaporphyrinato complex Pyz(4)TAPInCl (1) are reported and interpreted. In particular, the nonlinear optical transmission of the complex and the excited states involved in the nonlinear absorption have been determined at the frequency of the second harmonic generation of a Nd:YAG laser in the nanosecond time regime. Pyz(4)TAPInCl has an excited-state absorption cross section larger than its ground state in the 460-540 nm spectral region, and it shows an optical limiting (OL) behavior at 532 nm, which derives from a sequential two-photon absorption with a larger absorption cross section of the excited triplet state with respect to the ground state. It results that the absorption cross section of 1 in the excited triplet state is 7.8 x 10(-18) cm(2) vs 0.9 x 10(-18) cm(2) of the ground state at the wavelength of OL analysis.

  19. Analyzing the dynamics of cell cycle processes from fixed samples through ergodic principles.

    PubMed

    Wheeler, Richard John

    2015-11-05

    Tools to analyze cyclical cellular processes, particularly the cell cycle, are of broad value for cell biology. Cell cycle synchronization and live-cell time-lapse observation are widely used to analyze these processes but are not available for many systems. Simple mathematical methods built on the ergodic principle are a well-established, widely applicable, and powerful alternative analysis approach, although they are less widely used. These methods extract data about the dynamics of a cyclical process from a single time-point "snapshot" of a population of cells progressing through the cycle asynchronously. Here, I demonstrate application of these simple mathematical methods to analysis of basic cyclical processes--cycles including a division event, cell populations undergoing unicellular aging, and cell cycles with multiple fission (schizogony)--as well as recent advances that allow detailed mapping of the cell cycle from continuously changing properties of the cell such as size and DNA content. This includes examples using existing data from mammalian, yeast, and unicellular eukaryotic parasite cell biology. Through the ongoing advances in high-throughput cell analysis by light microscopy, electron microscopy, and flow cytometry, these mathematical methods are becoming ever more important and are a powerful complementary method to traditional synchronization and time-lapse cell cycle analysis methods. © 2015 Wheeler. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  20. Effect of the processing cycle on dimensional changes of heat-polymerized denture base resins

    PubMed Central

    Savabi, Ghazal; Savabi, Omid; Dastgheib, Badrosadat; Nejatidanesh, Farahnaz

    2015-01-01

    Background: The second processing cycle for adding the artificial teeth to heat-polymerized acrylic resin denture bases may result in dimensional changes of the denture bases. The aim of this study was to evaluate the dimensional changes of the heat-polymerized acrylic resin denture bases with one and two-cycle processing methods. Materials and Methods: A metal edentulous maxillary arch was used for making 40 stone casts. Maxillary complete dentures were made with heat-polymerized acrylic resins (Meliodent and Acropars) with one and two stage processing methods (n = 10 for each group). Linear dimensional changes in anteroposterior and mediolateral distances and vertical changes in the first molar region were measured following each processing cycle, using a digital caliper. Mean percentage of the dimensional changes were subjected to two-way analysis of variance and Tukey honest significant difference tests (α = 0.05). Results: Postpolymerization contraction occurred in both anteroposterior and mediolateral directions in all studied groups; however, the vertical dimension was increased. Acropars acrylic resin showed the highest dimensional changes and the second processing cycle significantly affected the measured distances (P < 0.05). Meliodent acrylic resin was not significantly influenced by the processing method. Conclusion: Reheating of the acrylic resin denture bases for the addition of denture teeth result in linear dimensional changes, which can be clinically significant based on the acrylic resin used. PMID:26288618

  1. Gravitational effects of process-induced dislocations in silicon. [during thermal cycling

    NASA Technical Reports Server (NTRS)

    Porter, W. A.; Parker, D. L.

    1974-01-01

    Matters pertaining to semiconductor device fabrication were studied in terms of the influence of gravity on the production of dislocations in silicon wafers during thermal cycling in a controlled ambient where no impurities are present and oxidation is minimal. Both n-type and p-type silicon wafers having a diameter of 1.25 in to 1.5 in, with fixed orientation and resistivity values, were used. The surface dislocation densities were measured quantitatively by the Sirtl etch technique. The results show two significant features of the plastic flow phenomenon as it is related to gravitational stress: (1) the density of dislocations generated during a given thermal cycle is directly related to the duration of the cycle; and (2) the duration of the thermal cycle required to produce a given dislocation density is inversely related to the equilibrium temperature. Analysis of the results indicates that gravitational stress is instrumental in process-induced defect generation.

  2. From patterns to processes: Phase and density dependencies in the Canadian lynx cycle

    PubMed Central

    Stenseth, Nils C.; Falck, Wilhelm; Chan, Kung-Sik; Bjørnstad, Ottar N.; O’Donoghue, Mark; Tong, Howell; Boonstra, Rudy; Boutin, Stan; Krebs, Charles J.; Yoccoz, Nigel G.

    1998-01-01

    Across the boreal forest of North America, lynx populations undergo 10-year cycles. Analysis of 21 time series from 1821 to the present demonstrates that these fluctuations are generated by nonlinear processes with regulatory delays. Trophic interactions between lynx and hares cause delayed density-dependent regulation of lynx population growth. The nonlinearity, in contrast, appears to arise from phase dependencies in hunting success by lynx through the cycle. Using a combined approach of empirical, statistical, and mathematical modeling, we highlight how shifts in trophic interactions between the lynx and the hare generate the nonlinear process primarily by shifting functional response curves during the increase and the decrease phases. PMID:9860985

  3. Mechanisms of CO2 Capture into Monoethanolamine Solution with Different CO2 Loading during the Absorption/Desorption Processes.

    PubMed

    Lv, Bihong; Guo, Bingsong; Zhou, Zuoming; Jing, Guohua

    2015-09-01

    Though the mechanism of MEA-CO2 system has been widely studied, there is few literature on the detailed mechanism of CO2 capture into MEA solution with different CO2 loading during absorption/desorption processes. To get a clear picture of the process mechanism, (13)C nuclear magnetic resonance (NMR) was used to analyze the reaction intermediates under different CO2 loadings and detailed mechanism on CO2 absorption and desorption in MEA was evaluated in this work. The results demonstrated that the CO2 absorption in MEA started with the formation of carbamate according to the zwitterion mechanism, followed by the hydration of CO2 to form HCO3(-)/CO3(2-), and accompanied by the hydrolysis of carbamate. It is interesting to find that the existence of carbamate will be influenced by CO2 loading and that it is rather unstable at high CO2 loading. At low CO2 loading, carbamate is formed fast by the reaction between CO2 and MEA. At high CO2 loading, it is formed by the reaction of CO3(-)/CO3(2-) with MEA, and the formed carbamate can be easily hydrolyzed by H(+). Moreover, CO2 desorption from the CO2-saturated MEA solution was proved to be a reverse process of absorption. Initially, some HCO3(-) were heated to release CO2 and other HCO3(-) were reacted with carbamic acid (MEAH(+)) to form carbamate, and the carbamate was then decomposed to MEA and CO2.

  4. Closed-Cycle He-Cooled Absorption Cells Designed for a Bruker IFS-125HR: First Results Between 79 K and 297K

    NASA Astrophysics Data System (ADS)

    Mantz, Arlan W.; Sung, Keeyoon; Brown, Linda R.; Crawford, Timothy J.; Smith, Mary Ann H.; Devi, V. Malathy; Benner, D. Chris

    2010-06-01

    Gas absorption cells specifically designed to achieve stable temperatures down to ˜70 K to fit inside the sample compartment of an evacuated Bruker (IFS-125HR) Fourier Transform spectrometer (FTS) have been developed at Connecticut College, and tested at the Jet Propulsion Laboratory (JPL). In operation, the temperature-controlled cooling by a closed-cycle helium refrigerator achieved a temperature stability of ±0.01 K. The unwanted absorption features initially observed from cryo-deposits formed on the outside cell windows were eliminated by adding an internal vacuum shroud box around the coolable cell to isolate it from residual gases in the evacuated FTS chambers. The effects of vibrations arising from the closed-cycle helium refrigerator upon the FTS spectra were characterized. Using this set up, high resolution spectra of several methane isotopologues (such as 12CH_4, 13CH_4 and 12CH_3D) broadened by N_2, were recorded in the 1230 to 1850 cm-1 spectral region. Such data are needed to characterize the temperature dependence of line shapes at very low temperatures for remote sensing of outer planets and their moons. Results from the initial analysis of the R(2) manifold of the ν_4 fundamental band of 13CH_4 are discussed to examine whether the N_2-broadened half width coefficients follow a simple exponential temperature-dependence over the entire 80 - 296 K temperature range. This initial test was very successful, proving that a high precision Fourier transform spectrometer can be easily configured for spectroscopic studies at very low temperatures relevant to planetary atmospheres. Research described in this paper was performed at Connecticut College, the College of William and Mary, NASA Langley Research Center and the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.

  5. 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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Dynamical properties of the two-process model for sleep-wake cycles in infantile autism.

    PubMed

    Matsuura, Hirotsune; Tateno, Katsumi; Aou, Shuji

    2008-09-01

    The two-process model is a scheme for the timing of sleep that consists of homeostatic (Process S) and circadian (Process C) variables. The two-process model exhibits abnormal sleep patterns such as internal desynchronization or sleep fragmentation. Early infants with autism often experience sleep difficulties. Large day-by-day changes are found in the sleep onset and waking times in autistic children. Frequent night waking is a prominent property of their sleep. Further, the sleep duration of autistic children is often fragmented. These sleep patterns in infants with autism are not fully understood yet. In the present study, the sleep patterns in autistic children were reproduced by a modified two-process model using nonlinear analysis. A nap term was introduced into the original two-process model to reproduce the sleep patterns in early infants. The nap term and the time course of Process S are mentioned in the present study. Those parameters led to bifurcation of the sleep-wake cycle in the modified two-process model. In a certain range of these parameter sets, a small external noise was amplified, and an irregular sleep-wake cycle appeared. The short duration of sleep led to another irregular sleep onset or waking. Consequently, an irregular sleep-wake cycle appeared in early infantile autism.

  7. Developing a vacuum thermal stripping - acid absorption process for ammonia recovery from anaerobic digester effluent.

    PubMed

    Ukwuani, Anayo T; Tao, Wendong

    2016-12-01

    To prevent acetoclastic methanogens from ammonia inhibition in anaerobic digestion of protein-rich substrates, ammonia needs to be removed or recovered from digestate. This paper presents an innovative ammonia recovery process that couples vacuum thermal stripping with acid absorption. Ammonia is stripped out of digestate boiling at a temperature below the normal boiling point due to vacuum. Stripped ammonia is absorbed to a sulfuric acid solution, forming ammonium sulfate crystals as a marketable product. Three common types of digestate were found to have boiling point temperature-vacuum curves similar to water. Seven combinations of boiling temperature and vacuum (50 °C 16.6 kPa, 58 °C 20.0 kPa, 65 °C 25.1 kPa, 70 °C 33.6 kPa, 80 °C 54.0 kPa, 90 °C 74.2 kPa, and 100 °C 101.3 kPa) were tested for batch stripping of ammonia in dairy manure digestate. 93.3-99.9% of ammonia was stripped in 3 h. The Lewis-Whitman model fitted ammonia stripping process well. Ammonia mass transfer coefficient was significantly higher at boiling temperature 65-100 °C and vacuum pressure 25.1-101.3 kPa than 50-58 °C and 16.6-20.0 kPa. The low ammonia saturation concentrations (0-24 mg N/L) suggested a large driving force to strip ammonia. The optimum boiling point temperature - vacuum pressure for ammonia recovery in a recirculation line of a mesophilic digester was 65 °C and 25.1 kPa, at which the ammonia mass transfer coefficient was as high as 37.3 mm/h. Installation of a demister and liquid trap could avoid negative effects of higher stripping temperature and stronger vacuum on formation of ammonium sulfate crystals. Pilot tests demonstrated that high-purity ammonium sulfate crystals could be produced by controlling sulfuric acid content and maintaining acid solution saturated with ammonium sulfate. Although volatile organic compounds such as cyclohexene were found in the final acid solutions, no volatile organic compounds were found in the recovered

  8. Membrane Separation Processes for the Benefit of the Sulfur-Iodine and Hybrid Sulfur Thermochemical Cycles

    SciTech Connect

    Christopher J. Orme; John R. Klaehn; Frederick F. Stewart

    2009-05-01

    Thermochemical cycles have been proposed as processes for the manufacture of hydrogen from water in which the only effluent is oxygen. In this paper, membrane-based technologies are described that have the promise of enabling the further development of thermochemical cycle processes. In direct service of the sulfur-iodine (S-I) cycle, membranes have been studied for the concentration of HI and sulfuric acid using pervaporation. In this work, Nafion® and SPEEK membranes have effectively concentrated both acids at temperatures as high as 134 ºC without any significant degradation. Measured fluxes of water and separation factors are commercially competitive and have been characterized with respect to acid concentration in the feed streams. Further, hydrogen permeability is discussed at 300 ºC with the goal of providing a method for the removal of the product gas from HI in the decomposition step, thus increasing the productiveness of the equilibrium limited reaction.

  9. Absorption of human skin and its detecting platform in the process of laser cosmetology

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-Lin; Ouyang, Li; Wang, Yang

    2000-10-01

    Because of the melanin, hemoglobin and water molecules, etc. contained, light absorption of human skin tissue changes with wavelength of light. This is the principle used in laser cosmetology for treating pigment diseases and vascular lesion diseases as well as skin decoration such as body tattooing, eyebrow tattooing, etc. The parameters of treatment used in laser cosmetology principally come from the research of the skin tissue optical characteristics of whites, and it is not suitable for the Oriental. The absorption spectrum of yellow race alive skin has been researched. The detecting platform for use in the measuring of vivi-tissue absorption spectrum has been developed which using opto-electronic nondestructive testing and virtual instrument techniques. The degree of pathological changes of skin can be detected by this platform also, thus the shortcoming of dosage selection in laser clinical treatments which have been decided only by naked eye observation and past experience of doctors can be solved.

  10. Gas trace detection with cavity enhanced absorption spectroscopy: a review of its process in the field

    NASA Astrophysics Data System (ADS)

    Liu, Siqi; Luo, Zhifu; Tan, Zhongqi; Long, Xingwu

    2016-11-01

    Cavity-enhanced absorption spectroscopy (CEAS) is a technology in which the intracavity absorption is deduced from the intensity of light transmitted by the high finesse optical cavity. Then the samples' parameters, such as their species, concentration and absorption cross section, would be detection. It was first proposed and demonstrated by Engeln R. [1] and O'Keefe[2] in 1998. This technology has extraordinary detection sensitivity, high resolution and good practicability, so it is used in many fields , such as clinical medicine, gas detection and basic physics research. In this paper, we focus on the use of gas trace detection, including the advance of CEAS over the past twenty years, the newest research progresses, and the prediction of this technology's development direction in the future.

  11. Influence of formulation and processing on absorption and metabolism of flavan-3-ols from tea and cocoa.

    PubMed

    Neilson, Andrew P; Ferruzzi, Mario G

    2011-01-01

    Flavan-3-ols are a major subclass of the class of plant phytochemicals known as flavonoids. Flavan-3-ols are commonly found in fruit, vegetable, and botanical products, including tea, cocoa, grapes, and apples. Both monomeric catechins and polymeric procyanidins are common in the diet, along with several derivatives produced by degradation of these species during processing. Both epidemiological and biological evidence suggests a health-protective role for dietary flavan-3-ols, leading to increased interest in the bioavailability of these compounds from foods. Flavan-3-ol bioavailability depends on numerous factors, including digestive release, absorption, metabolism, and elimination. In addition to these in vivo factors, the complexity of whole-food systems (physical form, flavan-3-ol form and dose, macronutrient and micronutrient profile, processing, etc.) influences the absorption efficiency and circulating profile of flavan-3-ols. An understanding of how food matrices may influence flavan-3-ol absorption will provide a framework to design and develop functional products that positively affect flavan-3-ol absorption and, by extension, potential bioactivity.

  12. 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.

  13. 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.

  14. Effects of Estrogen and Estrus Cycle on Pharmacokinetics, Absorption and Disposition of Genistein in Female Sprague-Dawley Rats

    PubMed Central

    Kulkarni, Kaustubh H.; Yang, Zhen; Tao, Niu; Hu, Ming

    2014-01-01

    Genistein is an active soy isoflavone with anticancer activities but it is unknown why it has a higher oral bioavailability in female than in male rats. Our study determined the effects of estrus cycle on genistein’s oral bioavailability. Female rats with various levels of estrogen were orally administered with genistein or used in a four-site rat intestinal perfusion experiment. Rats in “proestrus” group (with elevated estrogen) had significantly reduced (57% decrease, p<0.05) oral bioavailability of total genistein (aglycone+conjugates) than those in “metoestrus” group (with basal level of estrogen). Female ovariectomized rats, due to lack of estrogen, showed oral bioavailability of total genistein similar to the “metoestrus” group but higher (155% increase, p<0.05) than the “proestrus” group. Based on intestinal perfusion studies, the increased bioavailability was partially attributed to the higher (>100% increase, p<0.05) hepatic disposition via glucuronidation and possibly more efficient enterohepatic recycling of genistein in the “metoestrus” group. Furthermore, chronic exogenous supplementation of estradiol in ovariectomized rats significantly reduced (77%, p<0.05) the oral bioavailability of total genistein, mostly via increased sulfation (>10 folds) in liver, to a level comparable to those in the “proestrus” group. In conclusion, the oral bioavailability of total genistein was inversely proportional to elevated estrogen levels in female rats, which is partially mediated through the regulation of hepatic enzymes responsible disposition of genistein. PMID:22757747

  15. Effects of estrogen and estrus cycle on pharmacokinetics, absorption, and disposition of genistein in female Sprague-Dawley rats.

    PubMed

    Kulkarni, Kaustubh H; Yang, Zhen; Niu, Tao; Hu, Ming

    2012-08-15

    Genistein is an active soy isoflavone with anticancer activities, but it is unknown why it has a higher oral bioavailability in female than in male rats. Our study determined the effects of estrus cycle on genistein's oral bioavailability. Female rats with various levels of estrogen were orally administered with genistein or used in a four-site rat intestinal perfusion experiment. Rats in "proestrus" group (with elevated estrogen) had significantly reduced (57% decrease, p < 0.05) oral bioavailability of total genistein (aglycone + conjugates) than those in "metoestrus" group (with basal level of estrogen). Female ovariectomized rats, due to lack of estrogen, showed oral bioavailability of total genistein similar to the "metoestrus" group but higher (155% increase, p < 0.05) than the "proestrus" group. On the basis of intestinal perfusion studies, the increased bioavailability was partially attributed to the higher (>100% increase, p < 0.05) hepatic disposition via glucuronidation and possibly more efficient enterohepatic recycling of genistein in the "metoestrus" group. Furthermore, chronic exogenous supplementation of estradiol in ovariectomized rats significantly reduced (77%, p < 0.05) the oral bioavailability of total genistein, mostly via increased sulfation (>10-fold) in liver, to a level comparable to those in the "proestrus" group. In conclusion, the oral bioavailability of total genistein was inversely proportional to elevated estrogen levels in female rats, which is partially mediated through the regulation of hepatic enzymes responsible disposition of genistein.

  16. Pressure Swing Absorption Device and Process for Separating CO{sub 2} from Shifted Syngas and its Capture for Subsequent Storage

    SciTech Connect

    Sirkar, Kamalesh; Jie, Xingming; Chau, John; Obuskovic, Gordana

    2013-03-31

    Using the ionic liquid (IL) 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]) as the absorbent on the shell side of a membrane module containing either a porous hydrophobized ceramic tubule or porous hydrophobized polyether ether ketone (PEEK) hollow fiber membranes, studies for CO{sub 2} removal from hot simulated pre-combustion shifted syngas were carried out by a novel pressure swing membrane absorption (PSMAB) process. Helium was used as a surrogate for H{sub 2} in a simulated shifted syngas with CO{sub 2} around 40% (dry gas basis). In this cyclic separation process, the membrane module was used to achieve non-dispersive gas absorption from a high-pressure feed gas (689-1724 kPag; 100-250 psig) at temperatures between 25-1000C into a stationary absorbent liquid on the module shell side during a certain part of the cycle followed by among other cycle steps controlled desorption of the absorbed gases from the liquid in the rest of the cycle. Two product streams were obtained, one He-rich and the other CO{sub 2}-rich. Addition of polyamidoamine (PAMAM) dendrimer of generation 0 to IL [bmim][DCA] improved the system performance at higher temperatures. The solubilities of CO{sub 2} and He were determined in the ionic liquid with or without the dendrimer in solution as well as in the presence or absence of moisture; polyethylene glycol (PEG) 400 was also studied as a replacement for the IL. The solubility selectivity of the ionic liquid containing the dendrimer for CO{sub 2} over helium was considerably larger than that for the pure ionic liquid. The solubility of CO{sub 2} and CO{sub 2}-He solubility selectivity of PEG 400 and a solution of the dendrimer in PEG 400 were higher than the corresponding ones in the IL, [bmim][DCA]. A mathematical model was developed to describe the PSMAB process; a numerical solution of the governing equations described successfully the observed performance of the PSMAB process for the pure ionic liquid-based system.

  17. LIFE CYCLE ASSESSMENT IN MANAGEMENT, PRODUCT AND PROCESS DESIGN, AND POLICY DECISION MAKING: A CONFERENCE REPORT

    EPA Science Inventory

    On 24 September 2003, life cycle assessment (LCA) practitioners and decision makers gathered at the InLCA/LCM Conference in Seattle, Washington, USA (see http://www.lcacenter.org/InLCA-LCM03/index.html) to discuss the role of LCA in management, product design, process development...

  18. Aligning Web-Based Tools to the Research Process Cycle: A Resource for Collaborative Research Projects

    ERIC Educational Resources Information Center

    Price, Geoffrey P.; Wright, Vivian H.

    2012-01-01

    Using John Creswell's Research Process Cycle as a framework, this article describes various web-based collaborative technologies useful for enhancing the organization and efficiency of educational research. Visualization tools (Cacoo) assist researchers in identifying a research problem. Resource storage tools (Delicious, Mendeley, EasyBib)…

  19. Conceptual Change in Elementary School Teacher Candidate Knowledge of Rock-Cycle Processes.

    ERIC Educational Resources Information Center

    Stofflett, Rene Therese

    1994-01-01

    Investigates the knowledge of elementary school teacher candidates on rock-cycle processes. Three different instructional interventions were used to improve their knowledge: (1) conceptual-change teaching; (2) traditional didactic teaching; and (3) microteaching. The conceptual-change group showed the most growth in understanding, supporting…

  20. Aligning Web-Based Tools to the Research Process Cycle: A Resource for Collaborative Research Projects

    ERIC Educational Resources Information Center

    Price, Geoffrey P.; Wright, Vivian H.

    2012-01-01

    Using John Creswell's Research Process Cycle as a framework, this article describes various web-based collaborative technologies useful for enhancing the organization and efficiency of educational research. Visualization tools (Cacoo) assist researchers in identifying a research problem. Resource storage tools (Delicious, Mendeley, EasyBib)…

  1. Conceptual Change in Elementary School Teacher Candidate Knowledge of Rock-Cycle Processes.

    ERIC Educational Resources Information Center

    Stofflett, Rene Therese

    1994-01-01

    Investigates the knowledge of elementary school teacher candidates on rock-cycle processes. Three different instructional interventions were used to improve their knowledge: (1) conceptual-change teaching; (2) traditional didactic teaching; and (3) microteaching. The conceptual-change group showed the most growth in understanding, supporting…

  2. Modeling carbon cycle process of soil profile in Loess Plateau of China

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Finke, P.; Guo, Z.; Wu, H.

    2011-12-01

    SoilGen2 is a process-based model, which could reconstruct soil formation under various climate conditions, parent materials, vegetation types, slopes, expositions and time scales. Both organic and inorganic carbon cycle processes could be simulated, while the later process is important in carbon cycle of arid and semi-arid regions but seldom being studied. After calibrating parameters of dust deposition rate and segments depth affecting elements transportation and deposition in the profile, modeling results after 10000 years were confronted with measurements of two soil profiles in loess plateau of China, The simulated trends of organic carbon and CaCO3 in the profile are similar to measured values. Relative sensitivity analysis for carbon cycle process have been done and the results show that the change of organic carbon in long time scale is more sensitive to precipitation, temperature, plant carbon input and decomposition parameters (decomposition rate of humus, ratio of CO2/(BIO+HUM), etc.) in the model. As for the inorganic carbon cycle, precipitation and potential evaporation are important for simulation quality, while the leaching and deposition of CaCO3 are not sensitive to pCO2 and temperature of atmosphere.

  3. Belowground Carbon Cycling Processes at the Molecular Scale: An EMSL Science Theme Advisory Panel Workshop

    SciTech Connect

    Hess, Nancy J.; Brown, Gordon E.; Plata, Charity

    2014-02-21

    As part of the Belowground Carbon Cycling Processes at the Molecular Scale workshop, an EMSL Science Theme Advisory Panel meeting held in February 2013, attendees discussed critical biogeochemical processes that regulate carbon cycling in soil. The meeting attendees determined that as a national scientific user facility, EMSL can provide the tools and expertise needed to elucidate the molecular foundation that underlies mechanistic descriptions of biogeochemical processes that control carbon allocation and fluxes at the terrestrial/atmospheric interface in landscape and regional climate models. Consequently, the workshop's goal was to identify the science gaps that hinder either development of mechanistic description of critical processes or their accurate representation in climate models. In part, this report offers recommendations for future EMSL activities in this research area. The workshop was co-chaired by Dr. Nancy Hess (EMSL) and Dr. Gordon Brown (Stanford University).

  4. Effect of the Machining Processes on Low Cycle Fatigue Behavior of a Powder Metallurgy Disk

    NASA Technical Reports Server (NTRS)

    Telesman, J.; Kantzos, P.; Gabb, T. P.; Ghosn, L. J.

    2010-01-01

    A study has been performed to investigate the effect of various machining processes on fatigue life of configured low cycle fatigue specimens machined out of a NASA developed LSHR P/M nickel based disk alloy. Two types of configured specimen geometries were employed in the study. To evaluate a broach machining processes a double notch geometry was used with both notches machined using broach tooling. EDM machined notched specimens of the same configuration were tested for comparison purposes. Honing finishing process was evaluated by using a center hole specimen geometry. Comparison testing was again done using EDM machined specimens of the same geometry. The effect of these machining processes on the resulting surface roughness, residual stress distribution and microstructural damage were characterized and used in attempt to explain the low cycle fatigue results.

  5. Kinetic and Thermodynamic Characterization of Enhanced Carbon Dioxide Absorption Process with Lithium Oxide-Containing Ternary Molten Carbonate.

    PubMed

    Deng, Bowen; Tang, Juanjuan; Mao, Xuhui; Song, Yuqiao; Zhu, Hua; Xiao, Wei; Wang, Dihua

    2016-10-04

    Efficient and high-flux capture of CO2 is the prerequisite of its utilization. Static absorption of CO2 with solid Li2O and molten salts (Li2O-free and Li2O-containing Li-Na-K carbonates) was investigated using a reactor with in situ pressure monitoring. The absorption capacity of dissolved Li2O was 0.835 molCO2/molLi2O at 723 K, larger than that of solid Li2O. For the solid Li2O absorbents, formation of solid Li2CO3 on the surface can retard the further reactions between Li2O and CO2, whereas the dissociation/dissolution effect of molten carbonate on Li2O improved the mass-specific absorption capacity of liquid Li2O. In Li2O-containing Li-Na-K molten carbonate, CO2 was mostly absorbed by alkaline oxide ions (O(2-)). The chemical interactions between CO2 and CO3(2-) contributed to CO2 uptake via formation of multiple carbonate ions. The mass transfer of these absorbing ions was found as the dominating factor governing the rate of static absorption. Higher temperatures reduced the thermodynamic tendency of CO2 absorption, but a lower viscosity at elevated temperature was conducive to absorption kinetics. Compared with the commonly used CaO absorbent, Li2O was much more dissolvable in molten carbonate. The Li2O-containing molten carbonate is potentially a promising medium for industrial carbon capture and electrochemical transformation process.

  6. Building Information Modeling (BIM) Primer. Report 1: Facility Life-Cycle Process and Technology Innovation

    DTIC Science & Technology

    2012-08-01

    Information and Technology Services was the first customer to use Evolve FM. The software has a modern platform, only uses space, and is user...Mississippi, to research the benefits of BIM throughout the life-cycle process with the aim of improving the quality of its services and provide a...ii Abstract The architecture, engineering, and construction industries are pursuing process and technological innovations to save time and money

  7. The Improvement of The Absorption Process Using A Computational Optimization in An Atmospheric General Circulation Model

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Miho; Nakajima, Teruyuki

    2009-03-01

    This study improves the gaseous absorption process scheme of the broadband radiative transfer code "mstrnX" that was developed by the Center for Climate System Research (CCSR) for efficient calculation of atmospheric radiative transfer in the general circulation models. This scheme is adopted the optimization method to decrease the number of quadrature points for wavenumber integration by using the correlated k-distribution method and to increase the computational efficiency in each spectral band. The objective function of the standard version is defined as the sum of errors in radiation fluxes and heating rate in six standard atmospheres, and we added six other atmospheric profiles in the doubling CO2 condition for the doubling CO2 version. The preferable errors of radiative flux is thought about 1-2 W/m2, however, it is desirable that the errors of radiative forcing of CO2 is less than 0.3 W/m2. So, we improve the doubling CO2 version to calculate the radiative forcings precisely. When integration points and weights are determined in each band, we select the results whose errors of the instantaneous radiative forcing at TOA, troposphere and surface are under 0.2 W/m2. Moreover, radiative forcings of other WMGHGs are considered as same as CO2. Then, we build a global warming version with 29 bands and 111 integration points. In this version, the maximum radiation flux error is less than 0.6 W/m2 in LW and 0.45 W/m2 in SW at all altitude, and the maximum heating rate error is less than 0.2 K/day in the troposphere and the stratosphere for any standard atmosphere. The radiative forcing can be evaluated with small errors not exceeding one standard deviation of samples of forcings from the AOGCMs except for the changes of N2O+CFCs case in the RTMIP experiment. It is found that the proposed optimization method is effective in maintaining a low computational cost with accuracy good enough for dynamical simulations with a GCM. MstrnX is now available from the Open

  8. The seasonal cycle of carbonate system processes in Ryder Bay, West Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Legge, Oliver J.; Bakker, Dorothee C. E.; Meredith, Michael P.; Venables, Hugh J.; Brown, Peter J.; Jones, Elizabeth M.; Johnson, Martin T.

    2017-05-01

    The carbon cycle in seasonally sea-ice covered waters remains poorly understood due to both a lack of observational data and the complexity of the system. Here we present three consecutive seasonal cycles of upper ocean dissolved inorganic carbon (DIC) and total alkalinity measurements from Ryder Bay on the West Antarctic Peninsula. We attribute the observed changes in DIC to four processes: mixing of water masses, air-sea CO2 flux, calcium carbonate precipitation/dissolution and photosynthesis/respiration. This approach enables us to resolve the main drivers of the seasonal DIC cycle and also investigate the mechanisms behind interannual variability in the carbonate system. We observe a strong, asymmetric seasonal cycle in the carbonate system, driven by physical processes and primary production. In summer, melting glacial ice and sea ice and a reduction in mixing with deeper water reduce the concentration of DIC in surface waters. The dominant process affecting the carbonate system is net photosynthesis which reduces DIC and the fugacity of CO2, making the ocean a net sink of atmospheric CO2. In winter, mixing with deeper, carbon-rich water and net heterotrophy increase surface DIC concentrations, resulting in pH as low as 7.95 and aragonite saturation states close to 1. We observe no clear seasonal cycle of calcium carbonate precipitation/dissolution but some short-lived features of the carbonate time series strongly suggest that significant precipitation of calcium carbonate does occur in the Bay. The variability observed in this study demonstrates that changes in mixing and sea-ice cover significantly affect carbon cycling in this dynamic environment. Maintaining this unique time series will allow the carbonate system in seasonally sea-ice covered waters to be better understood.

  9. A Multiobjective Optimization Including Results of Life Cycle Assessment in Developing Biorenewables-Based Processes.

    PubMed

    Helmdach, Daniel; Yaseneva, Polina; Heer, Parminder K; Schweidtmann, Artur M; Lapkin, Alexei A

    2017-09-22

    A decision support tool has been developed that uses global multiobjective optimization based on 1) the environmental impacts, evaluated within the framework of full life cycle assessment; and 2) process costs, evaluated by using rigorous process models. This approach is particularly useful in developing biorenewable-based energy solutions and chemicals manufacturing, for which multiple criteria must be evaluated and optimization-based decision-making processes are particularly attractive. The framework is demonstrated by using a case study of the conversion of terpenes derived from biowaste feedstocks into reactive intermediates. A two-step chemical conversion/separation sequence was implemented as a rigorous process model and combined with a life cycle model. A life cycle inventory for crude sulfate turpentine was developed, as well as a conceptual process of its separation into pure terpene feedstocks. The performed single- and multiobjective optimizations demonstrate the functionality of the optimization-based process development and illustrate the approach. The most significant advance is the ability to perform multiobjective global optimization, resulting in identification of a region of Pareto-optimal solutions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Effect of biologically produced sulfur on gas absorption in a biotechnological hydrogen sulfide removal process.

    PubMed

    Kleinjan, Wilfred E; Lammers, Jos N J J; de Keizer, Arie; Janssen, Albert J H

    2006-07-05

    Absorption of hydrogen sulfide in aqueous suspensions of biologically produced sulfur particles was studied in a batch stirred cell reactor, and in a continuous set-up, consisting of a lab-scale gas absorber column and a bioreactor. Presence of biosulfur particles was found to enhance the absorption rate of H(2)S gas in the mildly alkaline liquid. The mechanism for this enhancement was however found to depend on the type of particles used. In the gently stirred cell reactor only small hydrophilic particles were present (d(p) < 3 microm) and the enhancement of the H(2)S absorption rate can be explained from the heterogeneous reaction between dissolved H(2)S and solid elemental sulfur to polysulfide ions, S(x) (2-). Conditions favoring enhanced H(2)S absorption for these hydrophilic particles are: low liquid side mass transfer (k(L)), high sulfur content, and presence of polysulfide ions. In the set-up of gas absorber column and bioreactor, both small hydrophilic particles and larger, more hydrophobic particles were continuously produced (d(p) up to 20 microm). Here, observed enhancement could not be explained by the heterogeneous reaction between sulfide and sulfur, due to the relatively low specific particle surface area, high k(L), and low [S(x) (2-)]. A more likely explanation for enhancement here is the more hydrophobic behavior of the larger particles. A local increase of the hydrophobic sulfur particle concentration near the gas/liquid interface and specific adsorption of H(2)S at the particle surface can result in an increase in the H(2)S absorption rate. (c) 2006 Wiley Periodicals, Inc.

  11. Retinoid Uptake, Processing, and Secretion in Human iPS-RPE Support the Visual Cycle

    PubMed Central

    Muñiz, Alberto; Greene, Whitney A.; Plamper, Mark L.; Choi, Jae Hyek; Johnson, Anthony J.; Tsin, Andrew T.; Wang, Heuy-Ching

    2014-01-01

    Purpose. Retinal pigmented epithelium derived from human induced pluripotent stem (iPS) cells (iPS-RPE) may be a source of cells for transplantation. For this reason, it is essential to determine the functional competence of iPS-RPE. One key role of the RPE is uptake and processing of retinoids via the visual cycle. The purpose of this study is to investigate the expression of visual cycle proteins and the functional ability of the visual cycle in iPS-RPE. Methods. iPS-RPE was derived from human iPS cells. Immunocytochemistry, RT-PCR, and Western blot analysis were used to detect expression of RPE genes lecithin-retinol acyl transferase (LRAT), RPE65, cellular retinaldehyde-binding protein (CRALBP), and pigment epithelium–derived factor (PEDF). All-trans retinol was delivered to cultured cells or whole cell homogenate to assess the ability of the iPS-RPE to process retinoids. Results. Cultured iPS-RPE expresses visual cycle genes LRAT, CRALBP, and RPE65. After incubation with all-trans retinol, iPS-RPE synthesized up to 2942 ± 551 pmol/mg protein all-trans retinyl esters. Inhibition of LRAT with N-ethylmaleimide (NEM) prevented retinyl ester synthesis. Significantly, after incubation with all-trans retinol, iPS-RPE released 188 ± 88 pmol/mg protein 11-cis retinaldehyde into the culture media. Conclusions. iPS-RPE develops classic RPE characteristics and maintains expression of visual cycle proteins. The results of this study confirm that iPS-RPE possesses the machinery to process retinoids for support of visual pigment regeneration. Inhibition of all-trans retinyl ester accumulation by NEM confirms LRAT is active in iPS-RPE. Finally, the detection of 11-cis retinaldehyde in the culture medium demonstrates the cells' ability to process retinoids through the visual cycle. This study demonstrates expression of key visual cycle machinery and complete visual cycle activity in iPS-RPE. PMID:24255038

  12. Operando X-ray absorption and EPR evidence for a single electron redox process in copper catalysis

    SciTech Connect

    Lu, Qingquan; Zhang, Jian; Peng, Pan; Zhang, Guanghui; Huang, Zhiliang; Yi, Hong; Miller, Jeffrey T.; Lei, Aiwen

    2015-05-26

    An unprecedented single electron redox process in copper catalysis is confirmed using operando X-ray absorption and EPR spectroscopies. The oxidation state of the copper species in the interaction between Cu(II) and a sulfinic acid at room temperature, and the accurate characterization of the formed Cu(I) are clearly shown using operando X-ray absorption and EPR evidence. Further investigation of anion effects on Cu(II) discloses that bromine ions can dramatically increase the rate of the redox process. Moreover, it is proven that the sulfinic acids are converted into sulfonyl radicals, which can be trapped by 2-arylacrylic acids and various valuable β-keto sulfones are synthesized with good to excellent yields under mild conditions.

  13. Operando X-ray absorption and EPR evidence for a single electron redox process in copper catalysis

    DOE PAGES

    Lu, Qingquan; Zhang, Jian; Peng, Pan; ...

    2015-05-26

    An unprecedented single electron redox process in copper catalysis is confirmed using operando X-ray absorption and EPR spectroscopies. The oxidation state of the copper species in the interaction between Cu(II) and a sulfinic acid at room temperature, and the accurate characterization of the formed Cu(I) are clearly shown using operando X-ray absorption and EPR evidence. Further investigation of anion effects on Cu(II) discloses that bromine ions can dramatically increase the rate of the redox process. Moreover, it is proven that the sulfinic acids are converted into sulfonyl radicals, which can be trapped by 2-arylacrylic acids and various valuable β-keto sulfonesmore » are synthesized with good to excellent yields under mild conditions.« less

  14. Branching process deconvolution algorithm reveals a detailed cell-cycle transcription program.

    PubMed

    Guo, Xin; Bernard, Allister; Orlando, David A; Haase, Steven B; Hartemink, Alexander J

    2013-03-05

    Due to cell-to-cell variability and asymmetric cell division, cells in a synchronized population lose synchrony over time. As a result, time-series measurements from synchronized cell populations do not reflect the underlying dynamics of cell-cycle processes. Here, we present a branching process deconvolution algorithm that learns a more accurate view of dynamic cell-cycle processes, free from the convolution effects associated with imperfect cell synchronization. Through wavelet-basis regularization, our method sharpens signal without sharpening noise and can remarkably increase both the dynamic range and the temporal resolution of time-series data. Although applicable to any such data, we demonstrate the utility of our method by applying it to a recent cell-cycle transcription time course in the eukaryote Saccharomyces cerevisiae. Our method more sensitively detects cell-cycle-regulated transcription and reveals subtle timing differences that are masked in the original population measurements. Our algorithm also explicitly learns distinct transcription programs for mother and daughter cells, enabling us to identify 82 genes transcribed almost entirely in early G1 in a daughter-specific manner.

  15. Performance assessment and signal processing for range-integrated concentration measurement of gas species using supercontinuum absorption spectroscopy.

    PubMed

    Dobroc, Alexandre; Cézard, Nicolas

    2012-12-10

    In this paper, we propose signal-processing tools adapted to supercontinuum absorption spectroscopy, in order to predict the precision of gas species concentration estimation. These tools are based on Cramer-Rao bounds computations. A baseline-insensitive concentration estimation algorithm is proposed. These calculations are validated by statistical tests on simulated supercontinuum signals as well as experimental data using a near-infrared supercontinuum laser and a grating spectrometer.

  16. Influence of accounting for water-vapor continuum absorption on the calculation of radiative processes in the atmosphere

    NASA Astrophysics Data System (ADS)

    Chesnokova, T. Y.

    1999-01-01

    At present, the tendency of global warming of the earth climate is observed. The climate depends on even small changes of radiative processes in the atmosphere. According to recent conceptions, the 'green house' effect can be connected with the increasing concentration of minor gaseous components, such as CO2, CO, CH4, and freons, therewith the contribution of the letter is comparable to that of CO2. A radiance transfer through the atmosphere is performed through spectral transmission windows, in which one of the basic roles belongs to water vapor continuum absorption. Different recent models of continuum absorption, based on the experimental data, are considered here. The long-wave radiance flux calculation is made on the basis of these models. It is shown that the error of the radiative fluxes calculation in the transmission windows is of the same order as the contribution of some atmospheric minor gaseous constituents and often exceeds it. Therefore, the accurate analytical expressions, describing the water continuum absorption and accounting for the nonlinear dependence of the absorption on humidity, temperature, wavelength and other factors, are needed.

  17. Microwave absorption properties of BaGdxFe12-xO19 nanoparticles synthesized by wet milling process

    NASA Astrophysics Data System (ADS)

    Kaynar, Mehmet; Ozcan, Sadan; Shah, S.

    2013-03-01

    It is a big demand to have a wide band, easy to synthesize microwave absorption materials with a high absorption ratio according to their weight. As a solution, nanoparticles are used for the couple of years because of their tunable frequencies by just changing their particle size. Most interesting nano structures for this objective are ferrites. In this work as a microwave absorber, BaFe12O19 and BaGd2Fe10O19 nanoparticles with different particles size are synthesized by the wet milling process. Their crystal structure analyzed by XRD, mean particle sizes were calculated from XRD patterns using rietveld analysis and from TEM images. Magnetic properties are analyzed by using Quantum design VSM. Microwave absorption properties are measured by using coaxial transmission method with an Agilent E5071 VNA. With the change of the last milling time from 0 to 20-hour crystalline sizes are changed from 48 nm to 13 nm. Decrease of particle size give rise to a decrease at coercivity and saturation magnetization of the samples. Change at the hysteresis loops gives a clue to the change of the microwave absorption frequency which is directly observed from the microwave measurements. Supported by TUBITAK-BIDEB 2214-Abroad Research Scholarship program.

  18. Aluminum-Cycle Ion Exchange Process for Hardness Removal: A New Approach for Sustainable Softening.

    PubMed

    Li, Jinze; Koner, Suman; German, Michael; SenGupta, Arup K

    2016-11-01

    From a sustainability viewpoint, sodium exchange softening, although used widely, is under scrutiny due to its production of excess Na-laden spent regenerant and subsequent discharge to the environment. Many arid regions are introducing regulations disallowing dumping of concentrated sodium salts, the residuals from popular Na-exchange softening. The sodium content of the softened water is, also, always higher than in the feed, which poses a dietary health concern when used for drinking or cooking. An efficient, easy-to-operate hardness removal process with reduced sodium in both the treated water and in the spent regenerant is an unmet global need. Use of a cation exchange resin in Al(3+)-form for hardness removal, that is, exchange of divalent Ca(2+) or Mg(2+) with trivalent Al(3+), is counterintuitive, and this is particularly so, because the aluminum ion to be exchanged has higher affinity than calcium. Nevertheless, ion exchange accompanied by precipitation of aluminum hydroxide allows progress of the cation exchange reaction leading to hardness removal. Experimental results demonstrated that calcium can be consistently removed for multiple cycles using a stoichiometric amount of AlCl3 as the regenerant. The process essentially operates at the maximum possible thermodynamic efficiency: removal of one equivalent of Ca(2+) corresponds to use of one equivalent of Al(3+) as a regenerant. During the Al-cycle process there is no increase in Na(+) concentration and partial reduction in the total dissolved solids (TDS) of the treated water. It is noteworthy that the ion-exchange resin used, components of the fixed-bed column and operational protocol are nearly the same as traditional softening processes on Na-cycle. Thus, existing Na-cycle systems can be retrofitted into Al-cycle operation without major difficulty.

  19. On the Automatic Generation of Plans for Life Cycle Assembly Processes

    SciTech Connect

    CALTON,TERRI L.

    2000-01-01

    Designing products for easy assembly and disassembly during their entire life cycles for purposes including product assembly, product upgrade, product servicing and repair, and product disposal is a process that involves many disciplines. In addition, finding the best solution often involves considering the design as a whole and by considering its intended life cycle. Different goals and manufacturing plan selection criteria, as compared to initial assembly, require re-visiting significant fundamental assumptions and methods that underlie current assembly planning techniques. Previous work in this area has been limited to either academic studies of issues in assembly planning or to applied studies of life cycle assembly processes that give no attention to automatic planning. It is believed that merging these two areas will result in a much greater ability to design for, optimize, and analyze the cycle assembly processes. The study of assembly planning is at the very heart of manufacturing research facilities and academic engineering institutions; and, in recent years a number of significant advances in the field of assembly planning have been made. These advances have ranged from the development of automated assembly planning systems, such as Sandia's Automated Assembly Analysis System Archimedes 3.0{copyright}, to the startling revolution in microprocessors and computer-controlled production tools such as computer-aided design (CAD), computer-aided manufacturing (CAM), flexible manufacturing systems (EMS), and computer-integrated manufacturing (CIM). These results have kindled considerable interest in the study of algorithms for life cycle related assembly processes and have blossomed into a field of intense interest. The intent of this manuscript is to bring together the fundamental results in this area, so that the unifying principles and underlying concepts of algorithm design may more easily be implemented in practice.

  20. Modeling the evolution space of breakage fusion bridge cycles with a stochastic folding process.

    PubMed

    Greenman, C D; Cooke, S L; Marshall, J; Stratton, M R; Campbell, P J

    2016-01-01

    Breakage-fusion-bridge cycles in cancer arise when a broken segment of DNA is duplicated and an end from each copy joined together. This structure then 'unfolds' into a new piece of palindromic DNA. This is one mechanism responsible for the localised amplicons observed in cancer genome data. Here we study the evolution space of breakage-fusion-bridge structures in detail. We firstly consider discrete representations of this space with 2-d trees to demonstrate that there are [Formula: see text] qualitatively distinct evolutions involving [Formula: see text] breakage-fusion-bridge cycles. Secondly we consider the stochastic nature of the process to show these evolutions are not equally likely, and also describe how amplicons become localized. Finally we highlight these methods by inferring the evolution of breakage-fusion-bridge cycles with data from primary tissue cancer samples.

  1. [Muscle strength and mobility of nerve processes among women judoists taking into account their menstrual cycle].

    PubMed

    Kakiashvili, L O; Iashvili, G M; Chkhikvishvili, M A; Khvedelidze, K R

    2006-08-01

    The problem of female sports is considered foremost importance and attract vivid attention of scientists and coaches as well. This problem requires special research in order to establish effective means for high sportive achievements by the sports women, however, without deteriorating their health. Analysis of the obtained results showed that physical characteristics were changed in the process of permanent training. Sports women's loading should be increased step-by-step, in accordance with the level of functional possibilities and menstrual period. In 1,3 and 5 phases of menstrual cycle, physical activities have to be optimal and during the systematic exercises well answer supportive effect and in 2,4 menstrual cycles, the physical exercises may be maximal. Correct allocation of exercises activities considering the menstrual cycle gives the trainer possibility to train the sportsmen and enhance the sport effect.

  2. Enterprise and system of systems capability development life-cycle processes.

    SciTech Connect

    Beck, David Franklin

    2014-08-01

    This report and set of appendices are a collection of memoranda originally drafted circa 2007-2009 for the purpose of describing and detailing a models-based systems engineering approach for satisfying enterprise and system-of-systems life cycle process requirements. At the time there was interest and support to move from Capability Maturity Model Integration (CMMI) Level One (ad hoc processes) to Level Three. The main thrust of the material presents a rational exposâe of a structured enterprise development life cycle that uses the scientific method as a framework, with further rigor added from adapting relevant portions of standard systems engineering processes. While the approach described invokes application of the Department of Defense Architectural Framework (DoDAF), it is suitable for use with other architectural description frameworks.

  3. Absorption-heat-pump system

    DOEpatents

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  4. Impact of diabatic processes on the tropopause inversion layer formation in baroclinic life cycles

    NASA Astrophysics Data System (ADS)

    Kunkel, Daniel; Hoor, Peter; Wirth, Volkmar

    2015-04-01

    Observations of temperature profiles in the extratropical upper troposphere/lower stratosphere (UTLS) show the presence of an inversion layer just above the thermal tropopause, i.e., the tropopause inversion layer (TIL). In recent studies both diabatic and adiabatic processes have been identified to contribute to the formation of this layer. In particular, adiabatic simulations indicate a TIL formation without the explicit simulation of diabatic, i.e. radiative or humidity related, processes after wave breaking during baroclinic life cycles. One goal of this study is to assess the additional contribution of diabatic processes to the formation and strength of the TIL in such life cycles. Moreover, since irreversible stratosphere-troposphere exchange (STE) is another inherent feature of baroclinic life cycles and a consequence of diabatic processes, we study whether there is a relationship between STE and TIL. We use the non-hydrostatic model COSMO in an idealized mid-latitude channel configuration to simulate baroclinic life cycles. In a first step contributions of individual diabatic processes from turbulence, radiation, and cloud microphysics to the formation of the TIL are analyzed. These results are compared to those from adiabatic simulations of baroclinic life cycles in which the TIL forms during the life cycle with the limitation of being less sharp than in observations. In a second step the combined effects of several diabatic processes are studied to further include interactions between these processes as well as to advance towards a more realistic model setup. The results suggest a much more vigorous development of the TIL due to microphysics and the release of latent heat. Moreover, radiative effects can foster an increase in static stability above the thermal tropopause when large gradients of either water vapor or cloud ice are present at the level of the tropopause. By additionally adding sub-grid scale turbulence, a co-location of high static

  5. JPL Carbon Dioxide Laser Absorption Spectrometer Data Processing Results for the 2010 Flight Campaign

    NASA Technical Reports Server (NTRS)

    Jacob, Joseph C.; Spiers, Gary D.; Menzie, Robert T.; Christensen, Lance E.

    2011-01-01

    As a precursor to and validation of the core technology necessary for NASA's Active Sensing of CO2 Emissions over Nights, Days,and Seasons (ASCENDS) mission, we flew JPL's Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) in a campaign of five flights onboard NASA's DC-8 Airborne Laboratory in July 2010. This is the latest in a series of annual flight campaigns that began in 2006, and our first on the DC-8 aircraft.

  6. Industrial process system assessment: bridging process engineering and life cycle assessment through multiscale modeling.

    EPA Science Inventory

    The Industrial Process System Assessment (IPSA) methodology is a multiple step allocation approach for connecting information from the production line level up to the facility level and vice versa using a multiscale model of process systems. The allocation procedure assigns inpu...

  7. Industrial process system assessment: bridging process engineering and life cycle assessment through multiscale modeling.

    EPA Science Inventory

    The Industrial Process System Assessment (IPSA) methodology is a multiple step allocation approach for connecting information from the production line level up to the facility level and vice versa using a multiscale model of process systems. The allocation procedure assigns inpu...

  8. 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

  9. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts.

    PubMed

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-08-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  10. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts

    PubMed Central

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-01-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  11. Isolation of Indonesian cananga oil using multi-cycle pressure drop process.

    PubMed

    Kristiawan, Magdalena; Sobolik, Vaclav; Allaf, Karim

    2008-05-30

    New process, instantaneous controlled pressure drop (DIC) was applied on Cananga odorata dry flowers with the aim to isolate essential oil. DIC is based on high temperature, short time heating followed by an abrupt pressure drop into a vacuum. A part of volatile compounds is carried away from flowers in the form of vapor (DIC direct oil) that evolves adiabatically during the pressure drop (proper isolation process) and the other part remains in the DIC-treated flowers (DIC residual oil). In the present paper, the effect of DIC cycle number (1-9) and heating time (4.3-15.7 min) on the availability of oil compounds was investigated at three levels of steam pressure (0.28, 0.4 and 0.6 MPa). The availability was defined as the amount of a compound in direct or residual oil divided by the amount of this compound in the reference oil extracted from non-treated flowers by chloroform during 2h. The total availability and yield of volatiles in the direct oil increased with pressure and cycle number. At a higher pressure, the effect of heating time was insignificant. The amount of oxygenated monoterpenes and other light oxygenated compounds (i.e. predominantly exogenous compounds) in the residual flowers was lower than in the direct oil and this amount decreased with cycle number. On the other hand, the availability of oxygenated sesquiterpenes and other heavy oxygenated compounds (i.e. predominantly endogenous compounds) in residual flowers exhibited a maximum for about five cycles and their quantity at this point was three times as much as in the direct oil. The total availability of each compound at 0.6 MPa was higher than one. The rapid DIC process (0.6 MPa, 8 cycles, 6 min) gave better results than steam distillation (16 h) concerning direct oil yield (2.8%dm versus 2.5%dm) and content of oxygenated compounds (72.5% versus 61.7%).

  12. Krebs cycle dysfunction shapes epigenetic landscape of chromatin: novel insights into mitochondrial regulation of aging process.

    PubMed

    Salminen, Antero; Kaarniranta, Kai; Hiltunen, Mikko; Kauppinen, Anu

    2014-07-01

    Although there is a substantial literature that mitochondria have a crucial role in the aging process, the mechanism has remained elusive. The role of reactive oxygen species, mitochondrial DNA injuries, and a decline in mitochondrial quality control has been proposed. Emerging studies have demonstrated that Krebs cycle intermediates, 2-oxoglutarate (also known as α-ketoglutarate), succinate and fumarate, can regulate the level of DNA and histone methylation. Moreover, citrate, also a Krebs cycle metabolite, can enhance histone acetylation. Genome-wide screening studies have revealed that the aging process is linked to significant epigenetic changes in the chromatin landscape, e.g. global demethylation of DNA and histones and increase in histone acetylation. Interestingly, recent studies have revealed that the demethylases of DNA (TET1-3) and histone lysines (KDM2-7) are members of 2-oxoglutarate-dependent dioxygenases (2-OGDO). The 2-OGDO enzymes are activated by oxygen, iron and the major Krebs cycle intermediate, 2-oxoglutarate, whereas they are inhibited by succinate and fumarate. Considering the endosymbiont origin of mitochondria, it is not surprising that Krebs cycle metabolites can control the gene expression of host cell by modifying the epigenetic landscape of chromatin. It seems that age-related disturbances in mitochondrial metabolism can induce epigenetic reprogramming, which promotes the appearance of senescent phenotype and degenerative diseases. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. 17Oexcess in meteoric water: as a new isotopic parameter to decipher water cycle processes

    NASA Astrophysics Data System (ADS)

    Landais, A.; Guillevic, M.; Steen-Larsen, H.; Vimeux, F.; Bouygues, A.; Falourd, S.; Risi, C. M.; Bony, S.

    2009-12-01

    Classical water stable isotopes (dD and d18O) have been used for more than 50 years with the aim to understand the links between water cycle and climate. They provide information on either temperature or precipitation changes depending on the latitudes. Their combination, in the so-called d-excess, brings some information on climatic conditions occurring during non equilibrium processes along air masses histories (evaporation over the Oceans, reevaporation of droplets in convective systems, continental recycling or ice crystals formation). Recently, the possibility to measure with high precision d17O in water has enabled to introduce a new parameter, 17Oexcess, resulting from the combination of d18O and d17O. According to both observations and modeling works, this new isotopic parameter is able to decipher some of the non equilibrium processes: when measured in ice core, it is expected to be a more direct tracer of relative humidity of the oceanic evaporative regions than d-excess. In order to better understand what controls this new parameter as well as to extract the maximum climatic information from the combination of 17Oexcess and d-excess, we present different original studies combining these two parameters in several key regions. First, data collected in Niger, West Africa, at scales ranging from the convective system to the seasonal cycle confirm the strong influence of relative humidity on 17Oexcess through the rain reevaporation process. Second, seasonal cycles in the Zongo Valley (Tropical Bolivia) suggest that rain recycling along air masses trajectories have different signatures on d-excess and 17Oexcess leading to decipher the different processes. Third, we study how local processes (precipitation, sublimation) in polar region (Greenland) can affect 17Oexcess archived in ice core with respect to d-excess records through (1) isotopic measurements of vapor versus precipitation collected at the NEEM station and (2) seasonal cycles measured from snow pits.

  14. Optical beam induced current measurements based on two-photon absorption process in 4H-SiC bipolar diodes

    SciTech Connect

    Hamad, H.; Raynaud, C.; Bevilacqua, P.; Tournier, D.; Planson, D.; Vergne, B.

    2014-02-24

    Using a pulsed green laser with a wavelength of 532 nm, a duration pulse of ∼1 ns, and a mean power varying between 1 and 100 mW, induced photocurrents have been measured in 4H-SiC bipolar diodes. Considering the photon energy (2.33 eV) and the bandgap of 4H-SiC (3.2 eV), the generation of electron-hole pair by the conventional single photon absorption process should be negligible. The intensity of the measured photocurrents depends quadratically on the power beam intensity. This clearly shows that they are generated using two-photon absorption process. As in conventional OBIC (Optical Beam Induced Current), the measurements give an image of the electric field distribution in the structure under test, and the minority carrier lifetime can be extracted from the decrease of the photocurrent at the edge of the structure. The extracted minority carrier lifetime of 210 ns is consistent with results obtained in case of single photon absorption.

  15. Current advances of integrated processes combining chemical absorption and biological reduction for NO x removal from flue gas.

    PubMed

    Zhang, Shihan; Chen, Han; Xia, Yinfeng; Liu, Nan; Lu, Bi-Hong; Li, Wei

    2014-10-01

    Anthropogenic nitrogen oxides (NO x ) emitted from the fossil-fuel-fired power plants cause adverse environmental issues such as acid rain, urban ozone smoke, and photochemical smog. A novel chemical absorption-biological reduction (CABR) integrated process under development is regarded as a promising alternative to the conventional selective catalytic reduction processes for NO x removal from the flue gas because it is economic and environmentally friendly. CABR process employs ferrous ethylenediaminetetraacetate [Fe(II)EDTA] as a solvent to absorb the NO x following microbial denitrification of NO x to harmless nitrogen gas. Meanwhile, the absorbent Fe(II)EDTA is biologically regenerated to sustain the adequate NO x removal. Compared with conventional denitrification process, CABR not only enhances the mass transfer of NO from gas to liquid phase but also minimize the impact of oxygen on the microorganisms. This review provides the current advances of the development of the CABR process for NO x removal from the flue gas.

  16. Neural-Net Processed Characteristic Patterns for Measurement of Structural Integrity of Pressure Cycled Components

    NASA Technical Reports Server (NTRS)

    Decker, A. J.

    2001-01-01

    A neural-net inspection process has been combined with a bootstrap training procedure and electronic holography to detect changes or damage in a pressure-cycled International Space Station cold plate to be used for cooling instrumentation. The cold plate was excited to vibrate in a normal mode at low amplitude, and the neural net was trained by example to flag small changes in the mode shape. The NDE (nondestructive-evaluation) technique is straightforward but in its infancy; its applications are ad-hoc and uncalibrated. Nevertheless previous research has shown that the neural net can detect displacement changes to better than 1/100 the maximum displacement amplitude. Development efforts that support the NDE technique are mentioned briefly, followed by descriptions of electronic holography and neural-net processing. The bootstrap training procedure and its application to detection of damage in a pressure-cycled cold plate are discussed. Suggestions for calibrating and quantifying the NDE procedure are presented.

  17. Removal characteristics of CO2 using aqueous MEA/AMP solutions in the absorption and regeneration process.

    PubMed

    Choi, Won-Joon; Seo, Jong-Beom; Jang, Sang-Yong; Jung, Jong-Hyeon; Oh, Kwang-Joong

    2009-01-01

    The carbon dioxide (CO2) removal efficiency, reaction rate, and CO2 loading into aqueous blended monoethanolamine (MEA) + 2-amino-2-methyl-1-propanol (AMP) solutions to enhance absorption characteristics of MEA and AMP were carried out by the absorption/regeneration process. As a result, compared to aqueous MEA and AMP solutions, aqueous blended MEA + AMP solutions have a higher CO2 loading than MEA and a higher reaction rate than AMP. The CO2 loading of rich amine of aqueous 18 wt.% MEA + 12 wt.% AMP solution was 0.62 mol CO2/mol amine, which is 51.2% more than 30 wt.% MEA (0.41 mol CO2/mol amine). Consequently, blending MEA and AMP could be an effective way to design considering economical efficiency and used to operate absorber for a long time.

  18. Closed cycle construction: an integrated process for the separation and reuse of C&D waste.

    PubMed

    Mulder, Evert; de Jong, Tako P R; Feenstra, Lourens

    2007-01-01

    In The Netherlands, construction and demolition (C&D) waste is already to a large extent being reused, especially the stony fraction, which is crushed and reused as a road base material. In order to increase the percentage of reuse of the total C&D waste flow to even higher levels, a new concept has been developed. In this concept, called 'Closed Cycle Construction', the processed materials are being reused at a higher quality level and the quantity of waste that has to be disposed of is minimised. For concrete and masonry, the new concept implies that the material cycle will be completely closed, and the original constituents (clay bricks, gravel, sand, cement stone) are recovered in thermal processes. The mixed C&D waste streams are separated and decontaminated. For this purpose several dry separation techniques are being developed. The quality of the stony fraction is improved so much, that this fraction can be reused as an aggregate in concrete. The new concept has several benefits from a sustainability point of view, namely less energy consumption, less carbon dioxide emission, less waste production and less land use (for excavation and disposal sites). One of the most remarkable benefits of the new concept is that the thermal process steps are fuelled with the combustible fraction of the C&D waste itself. Economically the new process is more or less comparable with the current way of processing C&D waste. On the basis of the positive results of a feasibility study, currently a pilot and demonstration project is being carried out. The aim is to optimise the different process steps of the Closed Cycle Construction process on a laboratory scale, and then to verify them on a large scale. The results of the project are promising, so far.

  19. Decoupling of sulfur and nitrogen cycling due to biotic processes in a tropical rainforest

    NASA Astrophysics Data System (ADS)

    Yi-Balan, Simona A.; Amundson, Ronald; Buss, Heather L.

    2014-10-01

    We examined the terrestrial sulfur (S) cycle in the wet tropical Luquillo Experimental Forest (LEF), Puerto Rico. In two previously instrumented watersheds (Icacos and Bisley), chemical and isotopic measurements of carbon (C), nitrogen (N) and S were used to explore the inputs, in-soil processing, and losses of S through comparison to the N cycle. Additionally, the impact of soil forming factors (particularly climate, organisms, topography and parent material) on S cycling in this system was considered. Atmospheric inputs (δ34S values of 16.1 ± 2.8‰), from a mixture of marine and anthropogenic sources, delivered an estimated 2.2 g S/(m2yr) at Icacos, and 1.8 g S/(m2yr) at Bisley. Bedrock N and S inputs to soil were minimal. We estimated a hydrologic export of 1.7 ± 0.1 g S/(m2yr) at Icacos, and 2.5 ± 0.2 g S/(m2yr) at Bisley. Stream baseflow S isotope data revealed significant bedrock S in the hydrologic export at Bisley (with a distinctive δ34S values of 1.6 ± 0.7‰), but not at Icacos. Pore water data supported the co-occurrence of at least three major biological S-fractionating processes in these soils: plant uptake, oxidative degradation of organic S and bacterial sulfate reduction. The rates and relative importance of these processes varied in time and space. Vegetation litter was 3-5‰ depleted in 34S compared to the average pore water, providing evidence for fractionation during uptake and assimilation. Out of all abiotic soil forming factors, climate, especially the high rainfall, was the main driver of S biogeochemistry in the LEF by dictating the types and rates of processes. Topography appeared to impact S cycling by influencing redox conditions: C, N and S content decrease downslope at all sites, and the Bisley lower slope showed strongest evidence of bacterial sulfate reduction. Parent material type did not impact the soil S cycle significantly. To compare the fate of S and N in the soil, we used an advection model to describe the isotopic

  20. Nitrogen cycling and water pulses in semiarid grasslands: are microbial and plant processes temporally asynchronous?

    PubMed

    Dijkstra, Feike A; Augustine, David J; Brewer, Paul; von Fischer, Joseph C

    2012-11-01

    Precipitation pulses in arid ecosystems can lead to temporal asynchrony in microbial and plant processing of nitrogen (N) during drying/wetting cycles causing increased N loss. In contrast, more consistent availability of soil moisture in mesic ecosystems can synchronize microbial and plant processes during the growing season, thus minimizing N loss. We tested whether microbial N cycling is asynchronous with plant N uptake in a semiarid grassland. Using (15)N tracers, we compared rates of N cycling by microbes and N uptake by plants after water pulses of 1 and 2 cm to rates in control plots without a water pulse. Microbial N immobilization, gross N mineralization, and nitrification dramatically increased 1-3 days after the water pulses, with greatest responses after the 2-cm pulse. In contrast, plant N uptake increased more after the 1-cm than after the 2-cm pulse. Both microbial and plant responses reverted to control levels within 10 days, indicating that both microbial and plant responses were short lived. Thus, microbial and plant processes were temporally synchronous following a water pulse in this semiarid grassland, but the magnitude of the pulse substantially influenced whether plants or microbes were more effective in acquiring N. Furthermore, N loss increased after both small and large water pulses (as shown by a decrease in total (15)N recovery), indicating that changes in precipitation event sizes with future climate change could exacerbate N losses from semiarid ecosystems.

  1. Acetylation of RNA processing proteins and cell cycle proteins in mitosis.

    PubMed

    Chuang, Carol; Lin, Sue-Hwa; Huang, Feilei; Pan, Jing; Josic, Djuro; Yu-Lee, Li-yuan

    2010-09-03

    Mitosis is a highly regulated process in which errors can lead to genomic instability, a hallmark of cancer. During this phase of the cell cycle, transcription is silent and RNA translation is inhibited. Thus, mitosis is largely driven by post-translational modification of proteins, including phosphorylation, methylation, ubiquitination, and sumoylation. Here, we show that protein acetylation is prevalent during mitosis. To identify proteins that are acetylated, we synchronized HeLa cells in early prometaphase and immunoprecipitated lysine-acetylated proteins with antiacetyl-lysine antibody. The immunoprecipitated proteins were identified by LC-ESI-MS/MS analysis. These include proteins involved in RNA translation, RNA processing, cell cycle regulation, transcription, chaperone function, DNA damage repair, metabolism, immune response, and cell structure. Immunoprecipitation followed by Western blot analyses confirmed that two RNA processing proteins, eIF4G and RNA helicase A, and several cell cycle proteins, including APC1, anillin, and NudC, were acetylated in mitosis. We further showed that acetylation of APC1 and NudC was enhanced by apicidin treatment, suggesting that their acetylation was regulated by histone deacetylase. Moreover, treating mitotic cells with apicidin or trichostatin A induced spindle abnormalities and cytokinesis failure. These studies suggest that protein acetylation/deacetylation is likely an important regulatory mechanism in mitosis.

  2. Nutrient-cycling mechanisms other than the direct absorption from soil may control forest structure and dynamics in poor Amazonian soils.

    PubMed

    Grau, Oriol; Peñuelas, Josep; Ferry, Bruno; Freycon, Vincent; Blanc, Lilian; Desprez, Mathilde; Baraloto, Christopher; Chave, Jérôme; Descroix, Laurent; Dourdain, Aurélie; Guitet, Stéphane; Janssens, Ivan A; Sardans, Jordi; Hérault, Bruno

    2017-03-23

    Tropical forests store large amounts of biomass despite they generally grow in nutrient-poor soils, suggesting that the role of soil characteristics in the structure and dynamics of tropical forests is complex. We used data for >34 000 trees from several permanent plots in French Guiana to investigate if soil characteristics could predict the structure (tree diameter, density and aboveground biomass), and dynamics (growth, mortality, aboveground wood productivity) of nutrient-poor tropical forests. Most variables did not covary with site-level changes in soil nutrient content, indicating that nutrient-cycling mechanisms other than the direct absorption from soil (e.g. the nutrient uptake from litter, the resorption, or the storage of nutrients in the biomass), may strongly control forest structure and dynamics. Ecosystem-level adaptations to low soil nutrient availability and long-term low levels of disturbance may help to account for the lower productivity and higher accumulation of biomass in nutrient-poor forests compared to nutrient-richer forests.

  3. Nutrient-cycling mechanisms other than the direct absorption from soil may control forest structure and dynamics in poor Amazonian soils

    PubMed Central

    Grau, Oriol; Peñuelas, Josep; Ferry, Bruno; Freycon, Vincent; Blanc, Lilian; Desprez, Mathilde; Baraloto, Christopher; Chave, Jérôme; Descroix, Laurent; Dourdain, Aurélie; Guitet, Stéphane; Janssens, Ivan A.; Sardans, Jordi; Hérault, Bruno

    2017-01-01

    Tropical forests store large amounts of biomass despite they generally grow in nutrient-poor soils, suggesting that the role of soil characteristics in the structure and dynamics of tropical forests is complex. We used data for >34 000 trees from several permanent plots in French Guiana to investigate if soil characteristics could predict the structure (tree diameter, density and aboveground biomass), and dynamics (growth, mortality, aboveground wood productivity) of nutrient-poor tropical forests. Most variables did not covary with site-level changes in soil nutrient content, indicating that nutrient-cycling mechanisms other than the direct absorption from soil (e.g. the nutrient uptake from litter, the resorption, or the storage of nutrients in the biomass), may strongly control forest structure and dynamics. Ecosystem-level adaptations to low soil nutrient availability and long-term low levels of disturbance may help to account for the lower productivity and higher accumulation of biomass in nutrient-poor forests compared to nutrient-richer forests. PMID:28332608

  4. Product mass transfer resistance directly determined during freeze-drying cycle runs using tunable diode laser absorption spectroscopy (TDLAS) and pore diffusion model.

    PubMed

    Kuu, Wei Y; O'Bryan, Kevin R; Hardwick, Lisa M; Paul, Timothy W

    2011-08-01

    The pore diffusion model is used to express the dry layer mass transfer resistance, [Formula: see text], as a function of the ratio r(e)/?, where r(e) is the effective pore radius and ? is the tortuosity factor of the dry layer. Using this model, the effective pore radius of the dry layer can be estimated from the sublimation rate and product temperature profiles measured during primary drying. Freeze-drying cycle runs were performed using the LyoStar II dryer (FTS Systems), with real-time sublimation rate profiles during freeze drying continuously measured by tunable diode laser absorption spectroscopy (TDLAS). The formulations chosen for demonstration of the proposed approach include 5% mannitol, 5% sucrose, 5% lactose, 3% mannitol plus 2% sucrose, and a parenteral nutrition formulation denoted VitaM12. The three different methods used for determination of the product resistance are: (1) Using both the sublimation rate and product temperature profiles, (2) using the sublimation rate profile alone, and (3) using the product temperate profile alone. Unlike the second and third methods, the computation procedure of first method does not need solution of the complex heat and mass transfer equations.

  5. [Study on Differential Optical Absorption Spectroscopy Data Processing Based on Chirp-Z Transformation].

    PubMed

    Zheng, Hai-ming; Li, Guang-jie; Wu, Hao

    2015-06-01

    Differential optical absorption spectroscopy (DOAS) is a commonly used atmospheric pollution monitoring method. Denoising of monitoring spectral data will improve the inversion accuracy. Fourier transform filtering method is effectively capable of filtering out the noise in the spectral data. But the algorithm itself can introduce errors. In this paper, a chirp-z transform method is put forward. By means of the local thinning of Fourier transform spectrum, it can retain the denoising effect of Fourier transform and compensate the error of the algorithm, which will further improve the inversion accuracy. The paper study on the concentration retrieving of SO2 and NO2. The results show that simple division causes bigger error and is not very stable. Chirp-z transform is proved to be more accurate than Fourier transform. Results of the frequency spectrum analysis show that Fourier transform cannot solve the distortion and weakening problems of characteristic absorption spectrum. Chirp-z transform shows ability in fine refactoring of specific frequency spectrum.

  6. Parametric Studies of the Ejector Process within a Turbine-Based Combined-Cycle Propulsion System

    NASA Technical Reports Server (NTRS)

    Georgiadis, Nicholas J.; Walker, James F.; Trefny, Charles J.

    1999-01-01

    Performance characteristics of the ejector process within a turbine-based combined-cycle (TBCC) propulsion system are investigated using the NPARC Navier-Stokes code. The TBCC concept integrates a turbine engine with a ramjet into a single propulsion system that may efficiently operate from takeoff to high Mach number cruise. At the operating point considered, corresponding to a flight Mach number of 2.0, an ejector serves to mix flow from the ramjet duct with flow from the turbine engine. The combined flow then passes through a diffuser where it is mixed with hydrogen fuel and burned. Three sets of fully turbulent Navier-Stokes calculations are compared with predictions from a cycle code developed specifically for the TBCC propulsion system. A baseline ejector system is investigated first. The Navier-Stokes calculations indicate that the flow leaving the ejector is not completely mixed, which may adversely affect the overall system performance. Two additional sets of calculations are presented; one set that investigated a longer ejector region (to enhance mixing) and a second set which also utilized the longer ejector but replaced the no-slip surfaces of the ejector with slip (inviscid) walls in order to resolve discrepancies with the cycle code. The three sets of Navier-Stokes calculations and the TBCC cycle code predictions are compared to determine the validity of each of the modeling approaches.

  7. The Sulfur-Iodine Cycle: Process Analysis and Design Using Comprehensive Phase Equilibrium Measurements and Modeling

    SciTech Connect

    Thies, Mark C.; O'Connell, J. P.; Gorensek, Maximilian B.

    2010-01-10

    Of the 100+ thermochemical hydrogen cycles that have been proposed, the Sulfur-Iodine (S-I) Cycle is a primary target of international interest for the centralized production of hydrogen from nuclear power. However, the cycle involves complex and highly nonideal phase behavior at extreme conditions that is only beginning to be understood and modeled for process simulation. The consequence is that current designs and efficiency projections have large uncertainties, as they are based on incomplete data that must be extrapolated from property models. This situation prevents reliable assessment of the potential viability of the system and, even more, a basis for efficient process design. The goal of this NERI award (05-006) was to generate phase-equilibrium data, property models, and comprehensive process simulations so that an accurate evaluation of the S-I Cycle could be made. Our focus was on Section III of the Cycle, where the hydrogen is produced by decomposition of hydroiodic acid (HI) in the presence of water and iodine (I2) in a reactive distillation (RD) column. The results of this project were to be transferred to the nuclear hydrogen community in the form of reliable flowsheet models for the S-I process. Many of the project objectives were achieved. At Clemson University, a unique, tantalum-based, phase-equilibrium apparatus incorporating a view cell was designed and constructed for measuring fluid-phase equilibria for mixtures of iodine, HI, and water (known as HIx) at temperatures to 350 °C and pressures to 100 bar. Such measurements were of particular interest for developing a working understanding of the expected operation of the RD column in Section III. The view cell allowed for the IR observation and discernment of vapor-liquid (VL), liquid-liquid, and liquid-liquid-vapor (LLVE) equilibria for HIx systems. For the I2-H2O system, liquid-liquid equilibrium (LLE) was discovered to exist at temperatures up to 310-315 °C, in contrast to the models and

  8. Properties of solid dispersions of selected magnesium salts and the absorption process of Mg2+ ions in vitro

    NASA Astrophysics Data System (ADS)

    Marcoin, Waclawa; Duda, Henryk; Chrobak, Dariusz

    2011-01-01

    The paper presents an application of phosphatidylcholine 45% (PC 45) and polyvinylpyrrolidone (PVP) in formulations of magnesium salts such as Mg(VitB6) and Mg(VitB6Arg) prepared by solid dispersion (SD) techniques. The evaluation of influence of the selected carriers on some physicochemical properties of solid dispersions and on the absorption process of Mg +2 ions in vitro were made. An infrared (IR) spectra study suggested creation of a hydrogen bond between the carriers and the examined magnesium salts. The results of the following thermal analysis: differential thermal analysis (DTA), thermogravimetry (TG), and differential scanning calorimetry (DSC) showed that application of PVP into SD lower the temperature of the decomposition process. However, in the case of PC 45 into SD the characteristic thermal effects of higher temperatures were observed. Moreover, values of the enthalpy SD of decomposition process were decreased. The results of these studies on absorption process of Mg2+ ions in vitro showed the positive influence of the applied carriers on the partition coefficient values (log P) in the examined formulation.

  9. Using pulse transit delay in Z-scan to discriminate between excited-state absorption and other nonlinear processes in ZnO nanocones.

    PubMed

    Shortell, Matthew P; Jaatinen, Esa A; Chang, Jin; Waclawik, Eric R

    2014-03-24

    We report a new approach that uses the single beam Z-scan technique, to discriminate between excited state absorption (ESA) and two and three photon nonlinear absorption. By measuring the apparent delay or advance of the pulse in reaching the detector, the nonlinear absorption can be unambiguously identified as either instantaneous or transient. The simple method does not require a large range of input fluences or sophisticated pulse-probe experimental apparatus. The technique is easily extended to any absorption process dependent on pulse width and to nonlinear refraction measurements. We demonstrate in particular, that the large nonlinear absorption in ZnO nanocones when exposed to nanosecond 532 nm pulses, is due mostly to ESA, not pure two-photon absorption.

  10. Chronic alcohol consumption and intestinal thiamin absorption: effects on physiological and molecular parameters of the uptake process.

    PubMed

    Subramanya, Sandeep B; Subramanian, Veedamali S; Said, Hamid M

    2010-07-01

    Thiamin is essential for normal cellular functions, and its deficiency leads to a variety of clinical abnormalities. Humans and other mammals obtain the vitamin via intestinal absorption. The intestine is exposed to two sources of thiamin, a dietary and a bacterial (i.e., normal microflora of the large intestine) source. Chronic alcohol consumption is associated with thiamin deficiency, which is caused (in part) by inhibition in intestinal thiamin absorption. However, little is known about the physiological and molecular aspects of the intestinal thiamin uptake process that are affected by chronic alcohol use. To address these issues, we used rats fed an alcohol-liquid diet and human intestinal epithelial HuTu-80 cells chronically exposed to ethanol as model systems. The results showed that chronic alcohol feeding to rats led to a significant inhibition in carrier-mediated thiamin transport across both the jejunal brush-border membrane and basolateral membrane domains. This was associated with a significant reduction in level of expression of thiamin transporter-1 (THTR-1), but not THTR-2, at the protein and mRNA levels. Level of expression of the heterogenous nuclear RNA of THTR-1 in the intestine of alcohol-fed rats was also decreased compared with their pair-fed controls. Chronic alcohol feeding also caused a significant inhibition in carrier-mediated thiamin uptake in rat colon. Studies with HuTu-80 cells chronically exposed to ethanol also showed a significant inhibition in carrier-mediated thiamin uptake. This inhibition was associated with a reduction in level of expression of human THTR-1 and THTR-2 at the protein, mRNA, and transcriptional (promoter activity) levels. These studies demonstrate that chronic alcohol feeding inhibits intestinal thiamin absorption via inhibition of the individual membrane transport event across the polarized absorptive epithelial cells. Furthermore, the inhibition is, at least in part, mediated via transcriptional mechanism(s).

  11. Knockout of Drosophila RNase ZL impairs mitochondrial transcript processing, respiration and cell cycle progression

    PubMed Central

    Xie, Xie; Dubrovsky, Edward B.

    2015-01-01

    RNase ZL is a highly conserved tRNA 3′-end processing endoribonuclease. Similar to its mammalian counterpart, Drosophila RNase ZL (dRNaseZ) has a mitochondria targeting signal (MTS) flanked by two methionines at the N-terminus. Alternative translation initiation yields two protein forms: the long one is mitochondrial, and the short one may localize in the nucleus or cytosol. Here, we have generated a mitochondria specific knockout of the dRNaseZ gene. In this in vivo model, cells deprived of dRNaseZ activity display impaired mitochondrial polycistronic transcript processing, increased reactive oxygen species (ROS) and a switch to aerobic glycolysis compensating for cellular ATP. Damaged mitochondria impose a cell cycle delay at the G2 phase disrupting cell proliferation without affecting cell viability. Antioxidants attenuate genotoxic stress and rescue cell proliferation, implying a critical role for ROS. We suggest that under a low-stress condition, ROS activate tumor suppressor p53, which modulates cell cycle progression and promotes cell survival. Transcriptional profiling of p53 targets confirms upregulation of antioxidant and cycB-Cdk1 inhibitor genes without induction of apoptotic genes. This study implicates Drosophila RNase ZL in a novel retrograde signaling pathway initiated by the damage in mitochondria and manifested in a cell cycle delay before the mitotic entry. PMID:26553808

  12. Rhizosphere Processes Are Quantitatively Important Components of Terrestrial Biogeochemical Cycles: Data & Models

    NASA Astrophysics Data System (ADS)

    Finzi, A.

    2016-12-01

    The rhizosphere is a hot spot and hot moment for biogeochemical cycles. Microbial activity, extracellular enzyme activity and element cycles are greatly enhanced by root derived carbon inputs. As such the rhizosphere may be an important driver of ecosystem responses to global changes such as rising temperatures and atmospheric CO2 concentrations. Empirical research on the rhizosphere is extensive but extrapolation of rhizosphere processes to large spatial and temporal scales is largely uninterrogated. Using a combination of field studies, meta-analysis and numerical models we have found good reason to think that scaling is possible. In this talk I discuss the results of this research and focus on the results of a new modeling effort that explicitly links root distribution and architecture with a model of microbial physiology to assess the extent to which rhizosphere processes may affect ecosystem responses to global change. Results to date suggest that root inputs of C and possibly nutrients (ie, nitrogen) impact the fate of new C inputs to the soil (ie, accumulation or loss) in response to warming and enhanced productivity at elevated CO2. The model also provides qualitative guidance on incorporating the known effects of ectomycorrhizal fungi on decomposition and rates of soil C and N cycling.

  13. Process analysis of CO{sub 2} capture from flue gas using carbonation/calcination cycles

    SciTech Connect

    Li, Z.S.; Cai, N.S.; Croiset, E.

    2008-07-15

    Process analysis of CO{sub 2} capture from flue gas using Ca-based carbonation/calcination cycles is presented here. A carbonation/calcination system is composed essentially of two reactors (an absorber and a regenerator) with Ca-based sorbent circulating between the two reactors (assumed here as fluidized beds). CO{sub 2} is, therefore, transferred from the absorber to the regenerator. Because of the endothermicity of the calcination reaction, a certain amount of coal is burned with pure oxygen in the regenerator. Detailed mass balance, heat balance and cost of electricity and CO{sub 2} mitigation for the carbonation/calcination cycles with three Ca-based sorbents in dual fluidized beds were calculated and analyzed to study the effect of the Ca-based sorbent activity decay on CO{sub 2} capture from flue gas. The three sorbents considered were: limestone, dolomite and CaO/Ca{sub 12}Al{sub 14}O{sub 33} (75/25 wt %) sorbent. All results, including the amount of coal and oxygen required, are presented with respect to the difference in calcium oxide conversion between the absorber and the regenerator, which is an important design parameter. Finally, costs of electricity and CO{sub 2} mitigation costs using carbonation/calcination cycles for the three sorbents were estimated. The results indicate that the economics of the carbonation/calcination process compare favorably with competing technologies for capturing CO{sub 2}.

  14. Ultraviolet absorption measurements of CF2 in the parallel plate pyrolytic chemical vapour deposition process

    NASA Astrophysics Data System (ADS)

    Cruden, Brett A.; Gleason, Karen K.; Sawin, Herbert H.

    2002-03-01

    Polytetrafluoroethylene films have been deposited for use as low dielectric constant materials. Deposition is performed through pyrolysis of hexafluoropropylene oxide (HFPO) to produce CF2, which can then polymerize and deposit as a thin film. The variation of CF2 concentration as a function of reactor conditions has been characterized by ultraviolet absorption spectroscopy. CF2 concentration is observed to go through a maximum with respect to both pressure and pyrolysis temperature when it is present in large amounts (~1014 cm-3). A one-dimensional model including known kinetic reactions for HFPO decomposition and CF2 recombination and multi-component diffusive transport has been applied to the parallel plate system. The result is seen to overestimate the measured concentration and does not capture the maxima observed versus pressure and temperature. An additional mechanism of particle formation, by CF2 insertion into (CF2)n oligomers, has been introduced to produce a kinetic model that explains the CF2 concentration measurements.

  15. Microscopic Modeling of Intersubband Optical Processes in Type II Semiconductor Quantum Wells: Linear Absorption

    NASA Technical Reports Server (NTRS)

    Li, Jian-Zhong; Kolokolov, Kanstantin I.; Ning, Cun-Zheng

    2003-01-01

    Linear absorption spectra arising from intersubband transitions in semiconductor quantum well heterostructures are analyzed using quantum kinetic theory by treating correlations to the first order within Hartree-Fock approximation. The resulting intersubband semiconductor Bloch equations take into account extrinsic dephasing contributions, carrier-longitudinal optical phonon interaction and carrier-interface roughness interaction which is considered with Ando s theory. As input for resonance lineshape calculation, a spurious-states-free 8-band kp Hamiltonian is used, in conjunction with the envelop function approximation, to compute self-consistently the energy subband structure of electrons in type II InAs/AlSb single quantum well structures. We demonstrate the interplay of nonparabolicity and many-body effects in the mid-infrared frequency range for such heterostructures.

  16. Photon assisted processes: Probability amplitudes for the absorption and emission of photons and dc-photocurrents

    SciTech Connect

    Micu, C.; Racolta, D.; Papp, E.

    2014-11-24

    In this paper one deals with the derivation of probability amplitudes characterizing the photon assisted injection of electrons in a two-terminal quantum conductor. For this purpose one accounts for spatially constant but time dependent periodic voltages applied on an Ohmic contact. Resorting to the discrete Fourier transform provides the probability amplitudes for the emission and absorption of photons in terms of squared Bessel functions of the first kind and integer order. Several kinds of ac-pulses like sinusoidal and dc+sinusoidal are assumed. Mean square values concerning photon numbers have been discussed in some more detail. Time averages of squared time dependent classical currents and leading corrections to the rescaled dc-photocurrent have also been accounted for.

  17. Microscopic Modeling of Intersubband Optical Processes in Type II Semiconductor Quantum Wells: Linear Absorption

    NASA Technical Reports Server (NTRS)

    Li, Jian-Zhong; Kolokolov, Kanstantin I.; Ning, Cun-Zheng

    2003-01-01

    Linear absorption spectra arising from intersubband transitions in semiconductor quantum well heterostructures are analyzed using quantum kinetic theory by treating correlations to the first order within Hartree-Fock approximation. The resulting intersubband semiconductor Bloch equations take into account extrinsic dephasing contributions, carrier-longitudinal optical phonon interaction and carrier-interface roughness interaction which is considered with Ando s theory. As input for resonance lineshape calculation, a spurious-states-free 8-band kp Hamiltonian is used, in conjunction with the envelop function approximation, to compute self-consistently the energy subband structure of electrons in type II InAs/AlSb single quantum well structures. We demonstrate the interplay of nonparabolicity and many-body effects in the mid-infrared frequency range for such heterostructures.

  18. Life cycle assessment of swine and dairy manure: pyrolysis and combustion processes.

    PubMed

    Fernandez-Lopez, M; Puig-Gamero, M; Lopez-Gonzalez, D; Avalos-Ramirez, Antonio; Valverde, J; Sanchez-Silva, L

    2015-04-01

    The valorization of three different manure samples via pyrolysis and combustion processes was evaluated. Dairy manure (sample Pre) was biologically pretreated by anaerobic digestion (sample Dig R) whereas swine manure (sample SW) was pretreated by a biodrying process. Thermal behavior of manure samples were studied by means of thermogravimetric analysis coupled with mass spectrometry (TGA-MS). These processes could be divided into four general stages: dehydration, devolatilization, char transformation (oxidation for combustion) and inorganic matter decomposition. The main differences observed among the samples were attributed to their different composition and pretreatment. The economic feasibility, energetic and environmental impacts of pyrolysis and combustion technologies for dairy samples were carried out by means of life cycle assessment (LCA) methodology. Four different scenarios were analyzed. The economic feasibility of the pyrolysis process was demonstrated, being sample Dig R the best environmental option. However, the combustion of sample Pre was the best energetic option. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, R.C.; Biermann, W.J.

    1989-05-09

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

  20. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, Robert C.; Biermann, Wendell J.

    1989-01-01

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

  1. Unveiling Microbial Carbon Cycling Processes in Key U.S. Soils using ''Omics''

    SciTech Connect

    Myrold, David D.; Bottomely, Peter J.; Jumpponen, Ari; Rice, Charles W.; Zeglin, Lydia H.; David, Maude M.; Jansson, Janet K.; Prestat, Emmanuel; Hettich, Robert L.

    2014-09-17

    Soils process and store large amounts of C; however, considerable uncertainty still exists about the details of that influence microbial partitioning of C into soil C pools, and what are the main influential forces that control the fraction of the C input that is stabilized. The soil microbial community is genotypically and phenotypically diverse. Despite our ability to predict the kinds of regional environmental changes that will accompany global climate change, it is not clear how the microbial community will respond to climate-induced modification of precipitation and inter-precipitation intervals, and if this response will affect the fate of C deposited into soil by the local plant community. Part of this uncertainty lies with our ignorance of how the microbial community adapts genotypically and physiologically to changes in soil moisture brought about by shifts in precipitation. Our overarching goal is to harness the power of multiple meta-omics tools to gain greater understanding of the functioning of whole-soil microbial communities and their role in C cycling. We will do this by meeting the following three objectives: 1. Further develop and optimize a combination of meta-omics approaches to study how environmental factors affect microbially-mediated C cycling processes. 2. Determine the impacts of long-term changes in precipitation timing on microbial C cycling using an existing long-term field manipulation of a tallgrass prairie soil. 3. Conduct laboratory experiments that vary moisture and C inputs to confirm field observations of the linkages between microbial communities and C cycling processes. We took advantage of our state-of-the-art expertise in community “omics” to better understand the functioning soil C cycling within the Great Prairie ecosystem, including our ongoing Konza Prairie soil metagenome flagship project at JGI and the unique rainfall manipulation plots (RaMPs) established at this site more than a decade ago. We employed a systems

  2. Apparatus and process to eliminate diffusional limitations in a membrane biological reactor by pressure cycling

    DOEpatents

    Efthymiou, George S.; Shuler, Michael L.

    1989-08-29

    An improved multilayer continuous biological membrane reactor and a process to eliminate diffusional limitations in membrane reactors in achieved by causing a convective flux of nutrient to move into and out of an immobilized biocatalyst cell layer. In a pressure cycled mode, by increasing and decreasing the pressure in the respective layers, the differential pressure between the gaseous layer and the nutrient layer is alternately changed from positive to negative. The intermittent change in pressure differential accelerates the transfer of nutrient from the nutrient layers to the biocatalyst cell layer, the transfer of product from the cell layer to the nutrient layer and the transfer of byproduct gas from the cell layer to the gaseous layer. Such intermittent cycling substantially eliminates mass transfer gradients in diffusion inhibited systems and greatly increases product yield and throughput in both inhibited and noninhibited systems.

  3. Life cycle assessment in management, product and process design, and policy decision making: a conference report.

    PubMed

    Cooper, Joyce; Vigon, Bruce; Curran, Mary Ann; Franklin, Bill

    2005-01-01

    On 24 September 2003, life cycle assessment (LCA) practitioners and decision makers gathered at the InLCA/LCM Conference in Seattle, Washington, USA (see http://www.lcacenter.org/InLCA-LCM03/index.html) to discuss the role of LCA in management, product design, process development, and regulatory/policy development decisions and to compare life cycle-based methods and tools with traditional product evaluation methods and tools. This article is a summary of that meeting and was prepared by the organizers as an overview of the many different technical, regulatory policy, and decision-making policy perspectives presented to an international gathering of participants representing academia and the industrial and regulatory communities.

  4. Large two-photon absorption cross sections of hemiporphyrazines in the excited state: the multiphoton absorption process of hemiporphyrazines with different central metals.

    PubMed

    Dini, Danilo; Calvete, Mario J F; Hanack, Michael; Amendola, Vincenzo; Meneghetti, Moreno

    2008-09-17

    A series of five hemiporphyrazines (Hps) with different coordinating central atoms (H2, GeCl2, InCl, Pt, Pb), and the acyclic derivative 1,3-bis-(6'-amino-4'-butoxy-2'-pyridylimino)-1,3-dihydroisoindoline have been synthesized and their multiphoton absorption properties examined at the second harmonic frequency of the Nd:YAG laser in the nanosecond time regime. Metal-free and platinum Hps display saturation of optical transmittance within incident fluence values of 6 J cm(-2). Comparison with other similar molecular structures like phthalocyanines and related molecules shows that Hps are strong nonlinear absorbers. The experimental curves of nonlinear transmission at 532 nm have been fitted by means of a three-level model with the occurrence of simultaneous two-photon absorption from an excited state. In the sole case of the InCl complex we found that a five-level model is needed because of the participation of triplet states. Contrary to phthalocyanines, naphthalocyanines, and porphyrins, a heavy central atom does not improve the nonlinear absorption properties since a different excited states dynamic is involved. The large nonlinear absorption of Hps combined with the very small absorption in the visible spectral range makes these molecules a very interesting class of molecules for nonlinear optical applications.

  5. Study of the Photodegradation Process of Vitamin E Acetate by Optical Absorption, Fluorescence, and Thermal Lens Spectroscopy

    NASA Astrophysics Data System (ADS)

    Tiburcio-Moreno, J. A.; Marcelín-Jiménez, G.; Leanos-Castaneda, O. L.; Yanez-Limon, J. M.; Alvarado-Gil, J. J.

    2012-11-01

    The stability of vitamin E acetate exposed to ultraviolet (UV) light was studied using three spectroscopic methods. An ethanol solution of vitamin E acetate was treated with either UVC light (254 nm) or UVA light (366 nm) during a period of 10 min followed by a study of UV-Vis optical absorption, then by fluorescence spectroscopy excitation by UV radiation at either 290 nm or 368 nm and, finally the solution was studied by thermal lens spectroscopy. Immediately, the same solution of vitamin E acetate was subjected to the UV irradiation process until completion of six periods of irradiation and measurements. UVC light treatment induced the appearance of a broad absorption band in the range of 310 nm to 440 nm with maximum absorbance at 368 nm, which progressively grew as the time of the exposure to UVC light increases. In contrast, UVA light treatment did not affect the absorption spectra of vitamin E acetate. Fluorescence spectra of the vitamin E acetate (without UV light treatment) showed no fluorescence when excited with 368 nm while exciting with 290 nm, an intense and broad emission band (300 nm to 440 nm) with a maximum at 340 nm appeared. When vitamin E acetate was treated with UVC light, this emission band progressively decreased as the time of the UVC light irradiation grew. No signal from UV-untreated vitamin E acetate could be detected by the thermal lens method. Interestingly, as the time of the UVC light treatment increased, the thermal lens signal progressively grew. Additional experiments performed to monitor the time evolution of the process during continuous UVC treatment of the vitamin E acetate using thermal lens spectroscopy exhibited a progressive increase of the thermal lens signal reaching a plateau at about 8000 s. This study shows that the vitamin E acetate is stable when it is irradiated with UVA light, while the irradiation with UVC light induces the formation of photodegradation products. Interestingly, this photodegradation process using

  6. Combinatorial life cycle assessment to inform process design of industrial production of algal biodiesel.

    PubMed

    Brentner, Laura B; Eckelman, Matthew J; Zimmerman, Julie B

    2011-08-15

    The use of algae as a feedstock for biodiesel production is a rapidly growing industry, in the United States and globally. A life cycle assessment (LCA) is presented that compares various methods, either proposed or under development, for algal biodiesel to inform the most promising pathways for sustainable full-scale production. For this analysis, the system is divided into five distinct process steps: (1) microalgae cultivation, (2) harvesting and/or dewatering, (3) lipid extraction, (4) conversion (transesterification) into biodiesel, and (5) byproduct management. A number of technology options are considered for each process step and various technology combinations are assessed for their life cycle environmental impacts. The optimal option for each process step is selected yielding a best case scenario, comprised of a flat panel enclosed photobioreactor and direct transesterification of algal cells with supercritical methanol. For a functional unit of 10 GJ biodiesel, the best case production system yields a cumulative energy demand savings of more than 65 GJ, reduces water consumption by 585 m(3) and decreases greenhouse gas emissions by 86% compared to a base case scenario typical of early industrial practices, highlighting the importance of technological innovation in algae processing and providing guidance on promising production pathways.

  7. SEMATECH's cycles of learning test for EUV photoresist and its applications for process improvement

    NASA Astrophysics Data System (ADS)

    Chun, Jun Sung; Jen, Shih-Hui; Petrillo, Karen; Montgomery, Cecilia; Ashworth, Dominic; Neisser, Mark; Saito, Takashi; Huli, Lior; Hetzer, David

    2014-04-01

    With current progress in exposure source power, novel resist materials, and post processing techniques, EUV is getting closer to the production environment. As reported continuously, SEMATECH established cycles of learning program. The data generated from the program has been utilized to measure current state of the art of EUV photoresist for production or pilot line use. Thanks to SEMATECH core and associate members' attention to the project, numerous EUV samples have been tested and they were based on the best performing EUV resists from associate members. This year we completed the evaluations for under-layers, lines and spaces, and contact holes. We also applied track based techniques to drive both low line edge roughness control and enlarge the process window with techniques such as FIRMTM and track based smoothing process. In this paper we will discuss about the results from cycles of learning test and show post-processing results of the three best line and space resists when combined with different FIRMTM materials.

  8. Phase behavior through pitch and duty cycle and its impact on process window

    NASA Astrophysics Data System (ADS)

    Buttgereit, Ute; Birkner, Robert; Seidel, Dirk; Perlitz, Sascha; Philipsen, Vicky; De Bisschop, Peter

    2009-04-01

    Immersion lithography has moved into 45nm node and will soon go into 32nm node. Alternating Phase Shifting Masks (alt. PSM's) are one of the most effective methods to enhance resolution and process window. . However there are two major challenges: intensity balancing and quartz dry etch process. The dry etch process requires not only an uniform quartz etch but also a good linearity over a wide range of feature sizes to ensure a 180° phase shift through pitch and duty cycle. Phase errors lead to an image placement error during printing becoming even worse through focus. As feature sizes shrink imaging effects and 3D mask effects impact the phase shift and accurate phase shift measurement becomes extremely important. In this paper we report on phase shift measurements through pitch and duty cycle on alt. PSM taken on the newly developed phase metrology system Phame® and compare them to rigorous 3D simulations. Furthermore we correlate the phase shift measurements to process window data such as maximum exposure latitude. Through pitch investigations on alt. PSM show that for print pitches below 200nm (wafer level) the phase shift drops significantly below 180° which will lead to an image placement error during printing and a shrinking process window. Furthermore a strong correlation between phase shift and maximum exposure latitude is shown. Largest maximum exposure latitude is achieved for phase shift close to 180°. Phame® enables optical phase shift measurement in critical production features down to 120nm half pitch providing the opportunity to optimize the quartz dry etch process in terms of signature and linearity. This will help to optimize the phase shift of critical features on alt. PSM for largest process window and hence increase end of line yields for reducing overall chip manufacturing costs.

  9. The thermodynamics of pyrochemical processes for liquid metal reactor fuel cycles

    SciTech Connect

    Johnson, I.

    1987-01-01

    The thermodynamic basis for pyrochemical processes for the recovery and purification of fuel for the liquid metal reactor fuel cycle is described. These processes involve the transport of the uranium and plutonium from one liquid alloy to another through a molten salt. The processes discussed use liquid alloys of cadmium, zinc, and magnesium and molten chloride salts. The oxidation-reduction steps are done either chemically by the use of an auxiliary redox couple or electrochemically by the use of an external electrical supply. The same basic thermodynamics apply to both the salt transport and the electrotransport processes. Large deviations from ideal solution behavior of the actinides and lanthanides in the liquid alloys have a major influence on the solubilities and the performance of both the salt transport and electrotransport processes. Separation of plutonium and uranium from each other and decontamination from the more noble fission product elements can be achieved using both transport processes. The thermodynamic analysis is used to make process design computations for different process conditions.

  10. Enhancement of microwave absorption properties on modified kapton film by ion implantation process

    NASA Astrophysics Data System (ADS)

    Purwanto, S.; Adi, W. A.; Taryana, Y.

    2017-04-01

    Kapton-polyimide films have been modified by using ion implantation of Fe and Gd ions at dose 1 × 1017 ions/cm2 and energy ions 30 keV. From X-ray diffractions (XRD) were verified the existence phases such as iron oxide, or Gd-oxide and graphitic carbon. Vibrating sample magnetometer (VSM) measurement the films showed a paramagnetic behavior. Microwave absorption (MWA) properties were measured by vector network analyzer (VNA) at X band range (8-12GHz). VNA measurement results showed the enhancement of MWA from -22dB for Kapton original film to -35dB for S11 vector direction and until -40 dB for S22 vector direction of modified Kapton film by Fe and Gd ions. It can be concluded that the nanostructure of embedded Fe-oxide or Gd-oxide nanoparticles on the near surface of Kapton film take a role and gives a rise the MWA properties of film.

  11. Microwave absorption properties of FeSi flaky particles prepared via a ball-milling process

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Yuan, Yong; Jiang, Jian-tang; Gong, Yuan-xun; Zhen, Liang

    2015-12-01

    Flaky FeSi alloy particles with different aspect ratio were produced via ball-milling and a subsequent annealing. The microstructure and the morphology of the particles were examined by XRD and SEM. The dc resistivity, the static magnetization properties and electromagnetic properties were measured. Particles with high aspect ratio were found possess high permittivity and permeability. On the other hand, the variation of grain size and defects density was found influence the permittivity and permeability. High specific area was believed contribute to the intense dielectric loss and the high shape magnetic anisotropy lead to high permeability in the target band. Increased electromagnetic parameters compel the absorption peak's shift to lower frequency. Coating using flaky FeSi particles milled for 12 h as fillers presented a reflection loss of -10 dB at 2 GHz and a matching thickness of 1.88 mm. The flaky FeSi alloy particles prepared through ball-milling and annealing can be promising candidates for EMA application at 1-4 GHz band.

  12. Metaproteogenomics reveals the soil microbial communities active in nutrient cycling processes under different tree species

    NASA Astrophysics Data System (ADS)

    Keiblinger, Katharina Maria; Masse, Jacynthe; Zühlke, Daniela; Riedel, Katharina; Zechmeister-Boltenstern, Sophie; Prescott, Cindy E.; Grayston, Sue

    2016-04-01

    Tree species exert strong effects on microbial communities in litter and soil and may alter rates of soil processes fundamental to nutrient cycling and carbon fluxes (Prescott and Grayston 2013). However, the influence of tree species on decomposition processes are still contradictory and poorly understood. An understanding of the mechanisms underlying plant influences on soil processes is important for our ability to predict ecosystem response to altered global/environmental conditions. In order to link microbial community structure and function to forest-floor nutrient cycling processes, we sampled forest floors under western redcedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesii) and Sitka spruce (Picea sitchensis) grown in nutrient-poor sites in common garden experiments on Vancouver island (Canada). We measured forest-floor total N, total C, initial NH4+ and NO3- concentrations, DOC, Cmic and Nmic. Gross rates of ammonification and NH4+ consumption were measured using the 15N pool-dilution method. Organic carbon quality was assessed through FTIR analyses. Microbial community structure was analysed by a metaproteogenomic approach using 16S and ITS amplification and sequencing with MiSeq platform. Proteins were extracted and peptides characterized via LC-MS/MS on a Velos Orbitrap to assess the active microbial community. Different microbial communities were active under the three tree species and variation in process rates were observed and will be discussed. This research provides new insights on microbial processes during organic matter decomposition. The metaproteogenomic approach enables us to investigate these changes with respect to possible effects on soil C-storage at even finer taxonomic resolution.

  13. Influence of process parameters on the weld lines formation in rapid heat cycle molding

    NASA Astrophysics Data System (ADS)

    Fiorotto, Marco; Lucchetta, Giovanni

    2011-05-01

    The insufficient entanglement of the molecular chains at the v-notch of a weld line impairs the mechanical strength and the surface quality of a plastic product. The rapid heat cycle molding technology (RHCM) has been recently used to enhance surface appearance of the parts, by thermally cycling the mold surface temperature. The mold temperature is the key of RHCM technology because it significantly affects productivity, energy efficiency and the quality of the final polymer part. In this work the influence of mold temperature on the weld lines depth and roughness were studied. Three different materials were tested. To investigate the influence of process parameters, a special mold insert was designed and manufactured. Weld lines geometry and roughness were quantitatively characterized by means of a profilometer. Experimental results show that is possible to increase the temperature to 10° C lower than the glass transition to obtain a high-gloss parts without weld lines with a significant reduction of cycle time and energy consumption.

  14. Self-organization and fractality in a metabolic processes of the Krebs cycle.

    PubMed

    Grytsay, V I; Musatenko, I V

    2013-01-01

    The metabolic processes of the Krebs cycle is studied with the help of a mathematical model. The autocatalytic processes resulting in both the formation of the self-organization in the Krebs cycle and the appearance of a cyclicity of its dynamics are determined. Some structural-functional connections creating the synchronism of an autoperiodic functioning at the transport in the respiratory chain and the oxidative phosphorylation are investigated. The conditions for breaking the synchronization of processes, increasing the multiplicity of cyclicity, and for the appearance of chaotic modes are analyzed. The phase-parametric diagram of a cascade of bifurcations showing the transition to a chaotic mode by the Feigenbaum scenario is obtained. The fractal nature of the revealed cascade of bifurcations is demonstrated. The strange attractors formed as a result of the folding are obtained. The results obtained give the idea of structural-functional connections, due to which the self-organization appears in the metabolism running in a cell. The constructed mathematical model can be applied to the study of the toxic and allergic effects of drugs and various substances on cell metabolism.

  15. Novel shortcut estimation method for regeneration energy of amine solvents in an absorption-based carbon capture process.

    PubMed

    Kim, Huiyong; Hwang, Sung June; Lee, Kwang Soon

    2015-02-03

    Among various CO2 capture processes, the aqueous amine-based absorption process is considered the most promising for near-term deployment. However, the performance evaluation of newly developed solvents still requires complex and time-consuming procedures, such as pilot plant tests or the development of a rigorous simulator. Absence of accurate and simple calculation methods for the energy performance at an early stage of process development has lengthened and increased expense of the development of economically feasible CO2 capture processes. In this paper, a novel but simple method to reliably calculate the regeneration energy in a standard amine-based carbon capture process is proposed. Careful examination of stripper behaviors and exploitation of energy balance equations around the stripper allowed for calculation of the regeneration energy using only vapor-liquid equilibrium and caloric data. Reliability of the proposed method was confirmed by comparing to rigorous simulations for two well-known solvents, monoethanolamine (MEA) and piperazine (PZ). The proposed method can predict the regeneration energy at various operating conditions with greater simplicity, greater speed, and higher accuracy than those proposed in previous studies. This enables faster and more precise screening of various solvents and faster optimization of process variables and can eventually accelerate the development of economically deployable CO2 capture processes.

  16. Overview of the 2nd State of the Carbon Cycle Report Process, results and next steps

    NASA Astrophysics Data System (ADS)

    Cavallaro, N.; Shrestha, G.; Najjar, R.; Romero-Lankao, P.; Mayes, M. A.; Reed, S.; Birdsey, R.; Zhu, Z.; Shrestha, G.; Cavallaro, N.; Zhu, Z.; Cavallaro, N.; Zhu, Z.; Shrestha, G.

    2016-12-01

    With official kick-off in public engagement and writing in the early Spring of 2016, the 2nd State of the Carbon Cycle Report (SOCCR-2) is now set to be completed and published by the U.S. Government as a Highly Influential Scientific (Interagency) Assessment, a product of the Sustained National Climate Assessment, in late 2017. This presentation will highlight the planning process, the achievements so far, public engagement needs and the scientific community's contribution in the production of SOCCR-2.

  17. Systems Analysis of an Advanced Nuclear Fuel Cycle Based on a Modified UREX+3c Process

    SciTech Connect

    E. R. Johnson; R. E. Best

    2009-12-28

    The research described in this report was performed under a grant from the U.S. Department of Energy (DOE) to describe and compare the merits of two advanced alternative nuclear fuel cycles -- named by this study as the “UREX+3c fuel cycle” and the “Alternative Fuel Cycle” (AFC). Both fuel cycles were assumed to support 100 1,000 MWe light water reactor (LWR) nuclear power plants operating over the period 2020 through 2100, and the fast reactors (FRs) necessary to burn the plutonium and minor actinides generated by the LWRs. Reprocessing in both fuel cycles is assumed to be based on the UREX+3c process reported in earlier work by the DOE. Conceptually, the UREX+3c process provides nearly complete separation of the various components of spent nuclear fuel in order to enable recycle of reusable nuclear materials, and the storage, conversion, transmutation and/or disposal of other recovered components. Output of the process contains substantially all of the plutonium, which is recovered as a 5:1 uranium/plutonium mixture, in order to discourage plutonium diversion. Mixed oxide (MOX) fuel for recycle in LWRs is made using this 5:1 U/Pu mixture plus appropriate makeup uranium. A second process output contains all of the recovered uranium except the uranium in the 5:1 U/Pu mixture. The several other process outputs are various waste streams, including a stream of minor actinides that are stored until they are consumed in future FRs. For this study, the UREX+3c fuel cycle is assumed to recycle only the 5:1 U/Pu mixture to be used in LWR MOX fuel and to use depleted uranium (tails) for the makeup uranium. This fuel cycle is assumed not to use the recovered uranium output stream but to discard it instead. On the other hand, the AFC is assumed to recycle both the 5:1 U/Pu mixture and all of the recovered uranium. In this case, the recovered uranium is reenriched with the level of enrichment being determined by the amount of recovered plutonium and the combined amount

  18. Coupling Computer-Aided Process Simulation and Estimations of Emissions and Land Use for Rapid Life Cycle Inventory Modeling

    EPA Science Inventory

    A methodology is described for developing a gate-to-gate life cycle inventory (LCI) of a chemical manufacturing process to support the application of life cycle assessment in the design and regulation of sustainable chemicals. The inventories were derived by first applying proces...

  19. A Technique for Decreasing Reactivity of Coal Material to Suppress the Oxygen Absorption Process

    NASA Astrophysics Data System (ADS)

    Timofeeva, S. S.; Lugovtsova, N. Yu; Gubanova, A. R.

    2016-08-01

    The paper describes the mechanisms of self-ignition formation in coal liable to spontaneous combustion, on the basis of experimental works performed to analyze heat and mass transfer in the coal-air system. A new approach was developed to the coal self-heating suppression and thermodynamic control of the oxidation process. The influence of coal moisture content and thermal behaviour of air in the cooling process was studied during moisture evaporation.

  20. Cell cycle regulation and cytoskeletal remodelling are critical processes in the nutritional programming of embryonic development.

    PubMed

    Swali, Angelina; McMullen, Sarah; Hayes, Helen; Gambling, Lorraine; McArdle, Harry J; Langley-Evans, Simon C

    2011-01-01

    Many mechanisms purport to explain how nutritional signals during early development are manifested as disease in the adult offspring. While these describe processes leading from nutritional insult to development of the actual pathology, the initial underlying cause of the programming effect remains elusive. To establish the primary drivers of programming, this study aimed to capture embryonic gene and protein changes in the whole embryo at the time of nutritional insult rather than downstream phenotypic effects. By using a cross-over design of two well established models of maternal protein and iron restriction we aimed to identify putative common "gatekeepers" which may drive nutritional programming.Both protein and iron deficiency in utero reduced the nephron complement in adult male Wistar and Rowett Hooded Lister rats (P<0.05). This occurred in the absence of damage to the glomerular ultrastructure. Microarray, proteomic and pathway analyses identified diet-specific and strain-specific gatekeeper genes, proteins and processes which shared a common association with the regulation of the cell cycle, especially the G1/S and G2/M checkpoints, and cytoskeletal remodelling. A cell cycle-specific PCR array confirmed the down-regulation of cyclins with protein restriction and the up-regulation of apoptotic genes with iron deficiency.The timing and experimental design of this study have been carefully controlled to isolate the common molecular mechanisms which may initiate the sequelae of events involved in nutritional programming of embryonic development. We propose that despite differences in the individual genes and proteins affected in each strain and with each diet, the general response to nutrient deficiency in utero is perturbation of the cell cycle, at the level of interaction with the cytoskeleton and the mitotic checkpoints, thereby diminishing control over the integrity of DNA which is allowed to replicate. These findings offer novel insight into the primary

  1. Agricultural Nutrient Cycling at the Strawberry Creek Watershed: Insights Into Processes Using Stable Isotope Analysis

    NASA Astrophysics Data System (ADS)

    Thuss, E.; English, M. C.; Spoelstra, J.

    2009-05-01

    When nitrogen availability exceeds biological demand, excess nitrogen, especially nitrate, may subsequently pollute ground and surface water. Agricultural practices in Southern Ontario typically supplement soils with organic and inorganic nutrients to aid in crop development, and employ various management techniques to limit nutrient loss. Excess nitrogen has several potential fates, which are controlled by the net effects of numerous nitrogen cycling reactions in the soil that are often difficult to measure directly. Nitrogen cycling in soils is controlled in large part by soil moisture, as it affects microbial activity and soil redox conditions. Stable isotope geochemistry is a powerful tool that provides information on nitrogen sources and processes. This study uses crop nitrogen and carbon isotope ratios to provide insights into the net effects of soil nitrogen cycling and nitrogen fate. This research was conducted at the Strawberry Creek Watershed (SCW), an agricultural research watershed located between Kitchener-Waterloo and Guelph, Ontario. The SCW exhibits elevated nitrate concentrations in groundwater, tile discharge, and the stream itself. Previous isotopic work revealed that this nitrate is largely derived from chemical fertilizer and manure applications. Field-scale hydrological processes lead to areas where the fate of applied nitrogen differs, which has an isotopic effect on the residual nitrogen that is available to plants. Results of this study indicate significant patterns in the isotopic signature of plant tissue, in both temporal and spatial scales. At the plot-scale where soil conditions are similar, there is little to no variation in foliar isotope values, but at the field-scale there appears to be a significant amount of variability related to soil moisture and nitrogen loss. This relationship can potentially provide insight into ideal conditions for nitrogen uptake efficiency. Reducing agricultural nitrogen leaching to ground and surface

  2. Life cycle assessment of bioethanol production from woodchips with modifications in the pretreatment process.

    PubMed

    Shadbahr, Jalil; Zhang, Yan; Khan, Faisal

    2015-01-01

    Pretreatment as a crucial step in the process of ethanol production has significant influences on the process efficiency and on the environmental performance of the bioethanol production from lignocellulosic biomass. In present life cycle analysis (LCA) study, two cases for pretreatment of woodchips were considered as the focal point of the ethanol plant. One was assumed as base scenario whereas the second is the proposed alternative by implementation of modifications on the base design. In the first stage, LCA results of pretreatment unit showed lower environmental impacts in respiratory inorganics and land use than in new scenario, while the base scenario revealed better performance in fossil fuels. The results of the second stage of LCA study demonstrated improvement in proposed design in most categories of environmental impacts such as 18.5 % in land use as well as 17 % improvement in ecosystem quality.

  3. Modeling the Oxygen Cycle in the Equatorial Pacific: Regulation of Physical and Biogeochemical Processes

    NASA Astrophysics Data System (ADS)

    Wang, X.; Murtugudde, R. G.; Zhang, D.

    2016-12-01

    Photosynthesis and respiration are important processes in all ecosystems on the Earth, in which carbon and oxygen are the two main elements. However, the oxygen cycle has received much less attention (relative to the carbon cycle) despite its big role in the earth system. Oxygen is a sensitive indicator of physical and biogeochemical processes in the ocean thus a key parameter for understanding the ocean's ecosystem and biogeochemistry. The Oxygen-Minimum-Zone (OMZ), often seen below 200 m, is a profound feature in the world oceans. There has been evidence of OMZ expansion over the past few decades in the tropical oceans. Climate models project that there would be a continued decline in dissolved oxygen (DO) and an expansion of the tropical OMZs under future warming conditions, which is of great concern because of the implications for marine organisms. We employ a validated three-dimensional model that simulates physical transport (circulation and vertical mixing), biological processes (O2 production and consumption) and ocean-atmosphere O2 exchange to quantify various sources and sinks of DO over 1980-2015. We show how we use observational data to improve our model simulation. Then we assess the spatial and temporal variability in simulated DO in the tropical Pacific Ocean, and explore the impacts of physical and biogeochemical processes on the DO dynamics, with a focus on the MOZ. Our analyses indicate that DO in the OMZ has a positive relationship with the 13ºC isotherm depth and a negative relationship with the concentration of dissolved organic material.

  4. Quantification of re-absorption and re-emission processes to determine photon recycling efficiency in perovskite single crystals

    PubMed Central

    Fang, Yanjun; Wei, Haotong; Dong, Qingfeng; Huang, Jinsong

    2017-01-01

    Photon recycling, that is, iterative self-absorption and re-emission by the photoactive layer itself, has been speculated to contribute to the high open-circuit voltage in several types of high efficiency solar cells. For organic–inorganic halide perovskites that have yielded highly efficient photovoltaic devices, however, it remains unclear whether the photon recycling effect is significant enough to improve solar cell efficiency. Here we quantitatively evaluate the re-absorption and re-emission processes to determine photon recycling efficiency in hybrid perovskite with its single crystals by measuring the ratio of the re-emitted photons to the initially excited photons, which is realized by modulating their polarization to differentiate them. The photon recycling efficiencies are revealed to be less than 0.5% in CH3NH3PbI3 and CH3NH3PbBr3 single crystals under excitation intensity close to one sun, highlighting the intrinsically long carrier recombination lifetime instead of the photon-recycling-induced photon propagation as the origin of their long carrier diffusion length. PMID:28220791

  5. Quantification of re-absorption and re-emission processes to determine photon recycling efficiency in perovskite single crystals

    NASA Astrophysics Data System (ADS)

    Fang, Yanjun; Wei, Haotong; Dong, Qingfeng; Huang, Jinsong

    2017-02-01

    Photon recycling, that is, iterative self-absorption and re-emission by the photoactive layer itself, has been speculated to contribute to the high open-circuit voltage in several types of high efficiency solar cells. For organic-inorganic halide perovskites that have yielded highly efficient photovoltaic devices, however, it remains unclear whether the photon recycling effect is significant enough to improve solar cell efficiency. Here we quantitatively evaluate the re-absorption and re-emission processes to determine photon recycling efficiency in hybrid perovskite with its single crystals by measuring the ratio of the re-emitted photons to the initially excited photons, which is realized by modulating their polarization to differentiate them. The photon recycling efficiencies are revealed to be less than 0.5% in CH3NH3PbI3 and CH3NH3PbBr3 single crystals under excitation intensity close to one sun, highlighting the intrinsically long carrier recombination lifetime instead of the photon-recycling-induced photon propagation as the origin of their long carrier diffusion length.

  6. Intersubband absorption in p-type Si 1-xGe x quantum dots on pre-patterned Si substrates made by a diblock copolymer process

    NASA Astrophysics Data System (ADS)

    Cha, Dongho; Ogawa, Masaaki; Chen, Christopher; Kim, Seongku; Lee, Jooyoung; Wang, Kang L.; Wang, Jiayu; Russell, Thomas P.

    2007-04-01

    In this work, intersubband absorption in the valence bands of Si 1-xGe x quantum dots is investigated. Using molecular beam epitaxy, boron-doped (10 20 cm -3) Ge dots with base dimensions of 15 nm, heights of 5-7 nm, and an aerial dot density of 10 11 cm -2 are grown on pre-patterned Si substrates. The patterned substrate is prepared by a diblock copolymer process. Fourier transform infrared (FTIR) spectroscopy is used to measure the infrared absorption of various structures (with different dot heights and dot compositions). As the height of quantum dots is decreased, the absorption peak is shifted to a longer wavelength region. For low germanium content ( x=0.5), there is also a red shift of the absorption peak. The results suggest that we can tune optical properties of Si 1-xGe x quantum dots for infrared detector applications. The polarization-dependent results demonstrate that these structures have significant normal-incidence absorption. This normal-incidence absorption comes from the strong quantum confinement of the small lateral size and non-zero momentum matrix elements. For low Ge content, there is very strong normal-incidence absorption. This observation suggests that we can control polarization dependence of intersubband absorption by adjusting Ge content.

  7. Nutrient absorption.

    PubMed

    Rubin, Deborah C

    2004-03-01

    Our understanding of nutrient absorption continues to grow, from the development of unique animal models and from studies in which cutting-edge molecular and cellular biologic approaches have been used to analyze the structure and function of relevant molecules. Studies of the molecular genetics of inherited disorders have also provided many new insights into these processes. A major advance in lipid absorption has been the cloning and characterization of several intestinal acyl CoA:monoacylglycerol acyltransferases; these may provide new targets for antiobesity drug therapy. Studies of intestinal cholesterol absorption and reverse cholesterol transport have encouraged the development of novel potential treatments for hyperlipidemia. Observations in genetically modified mice and in humans with mutations in glucose transporter 2 suggest the importance of a separate microsomal membrane transport pathway for glucose transport. The study of iron metabolism has advanced greatly with the identification of the hemochromatosis gene and the continued examination of the genetic regulation of iron absorptive pathways. Several human thiamine transporters have been identified, and their specific roles in different tissues are being explored.

  8. Low-cycle and high-cycle fatigue failure process characterization of CFRP cross-ply laminates

    SciTech Connect

    Takeda, N.; Ogihara, S.; Kobayashi, A.

    1994-12-31

    Damage progress in toughened-type CFRP cross-ply laminates under tensile fatigue loading was measured by the replica technique. The damage parameters, the transverse crack density and the delamination ratio, were presented. Based on above data, simple shear-lag analysis combined with the modified Paris law model was conducted to model the damage progress. In addition, a novel power-law model was proposed, which related the cyclic strain range and the number of cycles. The loading-unloading tests were also performed to obtain the Young`s modulus reduction and the permanent strain as functions of the damage state. The shear-lag predictions of the Young`s modulus reduction and the permanent strain showed good agreement with the experimental data, when the interaction between transverse cracking and delamination were taken into account.

  9. Terrestrial N Cycling And C Storage: Some Insights From A Process-based Land Surface Model

    NASA Astrophysics Data System (ADS)

    Zaehle, S.; Friend, A. D.; Friedlingstein, P.

    2008-12-01

    We present results of a new land surface model, O-CN, which includes a process-based coupling between the terrestrial cycling of energy, water, carbon, and nitrogen. The model represents the controls of the terrestrial nitrogen (N) cycling on carbon (C) pools and fluxes through photosynthesis, respiration, changes in allocation, and soil organic matter decomposition, and explicitly accounts for N leaching and gaseous losses. O-CN has been shown to give realistic results in comparison to observations at a wide range of scales, including in situ flux measurements, productivity databases, and atmospheric CO2 concentration data. O-CN is run for three free air carbon dioxide enrichment (FACE) sites (Duke, Oak Ridge, Aspen), and reproduces observed magnitudes of changes in net primary productivity, foliage area and foliage N content. Several alternative hypotheses concerning the control of N on vegetation growth and decomposition, including effects of diluting foliage N concentrations, down-regulation of photosynthesis and respiration, acclimation of C allocation patterns and biological N fixation, are tested with respect to their effect on long- term C sequestration estimate. Differences in initial N availability, small transient changes in N inputs and the assumed plasticity of C:N stoichiometry can lead to substantial differences in the simulated long-term changes in productivity and C sequestration. We discuss the capacity of observations obtained at FACE sites to evaluate these alternative hypotheses, and investigate implications of a transient versus instantaneous increase in atmospheric carbon dioxide for the magnitude of the simulated limiting effect of N on C cycling. Finally, we re-examine earlier model-based assessments of the terrestrial C sequestration potential using a global transient O-CN simulation driven by increases in atmospheric CO2, N deposition and climatic changes over the 21st century.

  10. Carbon Cycling in Restored Wisconsin Grasslands: Examining Linkages Between Plant Diversity, Microbial Communities and Ecosystem Processes

    NASA Astrophysics Data System (ADS)

    Cahill, K. N.; Kucharik, C. J.; Balser, T. C.; Foley, J. A.

    2002-12-01

    It is important to characterize the variability of carbon (C) fluxes and stocks and the relationship between biotic and abiotic factors and C sequestration, a proposed strategy to help mitigate climate change. An observation site to study C cycling was established on land enrolled in the USDA Conservation Reserve Program in southwestern Wisconsin in spring 2002 on silt-loam soil. The site was converted from intensive row-crop agriculture in 1987 to three adjacent land cover types: an assortment of native C4 grasses, two C3 grasses and a nitrogen-fixer, and a disk planted, no-tillage food plot rotation of maize and soybeans. Key goals of the study were to characterize the effect of plant species composition and microbial community characteristics on carbon cycling in an attempt to link above- and below-ground processes. Measurements of soil surface CO2 efflux were made on a near-weekly basis during the growing season using a LICOR-6400, concurrently with soil surface moisture adjacent to the CO2 collars. Thermocouples were installed to record hourly average air temperature and soil temperature at 5 depths, from 2 to 70 cm, and water content sensors made hourly average measurements at 15 and 30 cm. Leaf area index measurements were made weekly, aboveground vegetation biomass was collected monthly, and belowground root biomass was collected bimonthly. Monthly microbial measurements included an assessment of community physiological profiles using BiOLOG, and assays of community composition (lipid analysis) and activity. Preliminary results suggest that land cover types significantly altered carbon cycling and microbial community structure and function, leading to different rates of C sequestration.

  11. EXTENSION OF COMPUTER-AIDED PROCESS ENGINEERING APPLICATIONS TO ENVIRONMENTAL LIFE CYCLE ASSESSMENT AND SUPPLY CHAIN MANAGEMENT

    EPA Science Inventory

    The potential of computer-aided process engineering (CAPE) tools to enable process engineers to improve the environmental performance of both their processes and across the life cycle (from cradle-to-grave) has long been proffered. However, this use of CAPE has not been fully ach...

  12. EXTENSION OF COMPUTER-AIDED PROCESS ENGINEERING APPLICATIONS TO ENVIRONMENTAL LIFE CYCLE ASSESSMENT AND SUPPLY CHAIN MANAGEMENT

    EPA Science Inventory

    The potential of computer-aided process engineering (CAPE) tools to enable process engineers to improve the environmental performance of both their processes and across the life cycle (from cradle-to-grave) has long been proffered. However, this use of CAPE has not been fully ach...

  13. Proof-of-concept framework to separate recombination processes in thin silicon wafers using transient free-carrier absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Siah, S. C.; Winkler, M. T.; Powell, D. M.; Johnston, S. W.; Kanevce, A.; Levi, D. H.; Buonassisi, T.

    2015-03-01

    We present a proof-of-concept framework to independently determine the bulk Shockley-Read-Hall (SRH) lifetime and surface recombination velocity in silicon wafers self-consistently. We measure the transient decay of free-carrier absorption (FCA) using two different excitation wavelengths (1050 and 750 nm) for p-type crystalline Si (c-Si) wafers over a wide injection range and fit the FCA transients for the two excitation wavelengths in a coupled manner. In this way, we can estimate the surface recombination lifetime accurately. However, we find that the capability to uniquely measure extrinsic bulk-SRH recombination is challenging in the presence of other recombination processes and can be broadly categorized into five different regimes depending on the relative strengths of each recombination pathway.

  14. Hydride generation and condensation flame atomic absorption spectroscopic determination of antimony in raw coffee beans and processed coffee.

    PubMed

    Kuennen, R W; Hahn, M H; Fricke, F L; Wolnik, K A

    1982-09-01

    A method was developed for determining Sb at nanogram per gram levels in raw coffee beans and processed coffee. The procedure uses either total acid digestion or extraction with 6M HCl followed by hydride generation/condensation with subsequent revolatilization of stibine (SbH3) and detection by flame atomic absorption spectroscopy. The lowest quantifiable level, based on a 2 g (dry weight) sample, is 2 ng Sb/g. The results of recoveries on spiked samples, precision studies on composited coffee samples, and the analysis of National Bureau of Standards Standard Reference Materials demonstrate the reliability and accuracy of the procedure. Sb concentrations in coffee samples were verified by neutron activation analysis and inductively coupled plasma atomic emission spectroscopy. Advantages of the method compared with the AOAC colorimetric procedure and hydride generation without condensation are discussed.

  15. Biological and Physico-chemical Processes of Soil Organic Matter Cycling in Diverse Soils

    NASA Astrophysics Data System (ADS)

    Jagadamma, S.; Mayes, M. A.; Steinweg, J. M.; Post, W. M.; Wang, G.

    2011-12-01

    Soils comprise the largest biologically active terrestrial pool of organic carbon (OC). The top meter of soil contains 1500 Pg of OC which is 3 times that present in vegetation and two times the CO2-C present in atmosphere. Current soil C models simulate soil C pool sizes and turnover rates on post-hoc basis and the mechanisms governing soil OC cycling have not been integrated in such models. Therefore the scale of applicability and accuracy of predictions of current C models are questionable. Our current efforts are focused on developing a mechanistic framework of soil C cycling processes and its linkage to global C model. As part of this effort, we seek to understand the important cycling and interactive processes of OC compounds with the soil minerals and microbial community on a global suite of soils from temperate, tropical and arctic ecosystems. The selected OC compounds are glucose, cellulose, stearic acid and vanillic acid which are representative of SOM composition that contains 5-15% sugars, 20-50% starch, 10% proteins, 20-30% lignin and 2-5% lipids. We hypothesize that physico-chemical interactions between OC compounds and soil minerals determines the biological stability and distribution of such compounds in soils. Cycling of the selected 14C-labeled OC compounds were investigated as a function of soil type, soil depth and functional components of SOM (dissolved organic carbon, DOC; particulate organic matter, POM; and mineral associated organic matter, MAOM). This presentation will consist of the results from sorption and long-term incubation experiments conducted on diverse soils by the addition of 14C-glucose. Sorption of 14C-glucose on soil minerals was determined by batch equilibration experiments of MAOM fraction at a solid-to-solution ratio of 1:60 for 8 hours. A series of initial glucose solutions containing 0-100 mg C/L unlabeled C and 4000 dpm/ml labeled C were used. Maximum sorption capacity (Qmax) and affinity coefficient (K) were determined

  16. Effects of freeze-thaw cycles on anaerobic microbial processes in an Arctic intertidal mud flat.

    PubMed

    Sawicka, Joanna E; Robador, Alberto; Hubert, Casey; Jørgensen, Bo Barker; Brüchert, Volker

    2010-04-01

    Insight into the effects of repeated freezing and thawing on microbial processes in sediments and soils is important for understanding sediment carbon cycling at high latitudes acutely affected by global warming. Microbial responses to repeated freeze-thaw conditions were studied in three complementary experiments using arctic sediment collected from an intertidal flat that is exposed to seasonal freeze-thaw conditions (Ymerbukta, Svalbard, Arctic Ocean). The sediment was subjected to oscillating freeze-thaw incubations, either gradual, from -5 to 4 degrees C, or abrupt, from -20 to 10 degrees C. Concentrations of low-molecular weight carboxylic acids (volatile fatty acids) were measured and sulfate reduction was assessed by measuring (35)S sulfate reduction rates (SRRs). Gradual freeze-thaw incubation decreased microbial activity in the frozen state to 0.25 % of initial levels at 4 degrees C, but activity resumed rapidly reaching >60 % of initial activity in the thawed state. Exposure of sediments to successive large temperature changes (-20 versus 10 degrees C) decreased SRR by 80% of the initial activity, suggesting that a fraction of the bacterial community recovered rapidly from extreme temperature fluctuations. This is supported by 16S rRNA gene-based denaturing gradient gel electrophoresis profiles that revealed persistence of the dominant microbial taxa under repeated freeze-thaw cycles. The fast recovery of the SRRs suggests that carbon mineralization in thawing arctic sediment can resume without delay or substantial growth of microbial populations.

  17. Inorganic carbon cycling and biogeochemical processes in an Arctic inland sea (Hudson Bay)

    NASA Astrophysics Data System (ADS)

    Burt, William J.; Thomas, Helmuth; Miller, Lisa A.; Granskog, Mats A.; Papakyriakou, Tim N.; Pengelly, Leah

    2016-08-01

    The distributions of carbonate system parameters in Hudson Bay, which not only receives nearly one-third of Canada's river discharge but is also subject to annual cycles of sea-ice formation and melt, indicate that the timing and magnitude of freshwater inputs play an important role in carbon biogeochemistry and acidification in this unique Arctic ecosystem. This study uses basin-wide measurements of dissolved inorganic carbon (DIC) and total alkalinity (TA), as well as stable isotope tracers (δ18O and δ13CDIC), to provide a detailed assessment of carbon cycling processes within the bay. Surface distributions of carbonate parameters reveal the particular importance of freshwater inputs in the southern portion of the bay. Based on TA, we surmise that the deep waters in the Hudson Bay are largely of Pacific origin. Riverine TA end-members vary significantly both regionally and with small changes in near-surface depths, highlighting the importance of careful surface water sampling in highly stratified waters. In an along-shore transect, large increases in subsurface DIC are accompanied by equivalent decreases in δ13CDIC with no discernable change in TA, indicating a respiratory DIC production on the order of 100 µmol kg-1 DIC during deep water circulation around the bay.

  18. Laser cutting of various materials: Kerf width size analysis and life cycle assessment of cutting process

    NASA Astrophysics Data System (ADS)

    Yilbas, Bekir Sami; Shaukat, Mian Mobeen; Ashraf, Farhan

    2017-08-01

    Laser cutting of various materials including Ti-6Al-4V alloy, steel 304, Inconel 625, and alumina is carried out to assess the kerf width size variation along the cut section. The life cycle assessment is carried out to determine the environmental impact of the laser cutting in terms of the material waste during the cutting process. The kerf width size is formulated and predicted using the lump parameter analysis and it is measured from the experiments. The influence of laser output power and laser cutting speed on the kerf width size variation is analyzed using the analytical tools including scanning electron and optical microscopes. In the experiments, high pressure nitrogen assisting gas is used to prevent oxidation reactions in the cutting section. It is found that the kerf width size predicted from the lump parameter analysis agrees well with the experimental data. The kerf width size variation increases with increasing laser output power. However, this behavior reverses with increasing laser cutting speed. The life cycle assessment reveals that material selection for laser cutting is critical for the environmental protection point of view. Inconel 625 contributes the most to the environmental damages; however, recycling of the waste of the laser cutting reduces this contribution.

  19. Selection of organic process and source indicator substances for the anthropogenically influenced water cycle.

    PubMed

    Jekel, Martin; Dott, Wolfgang; Bergmann, Axel; Dünnbier, Uwe; Gnirß, Regina; Haist-Gulde, Brigitte; Hamscher, Gerd; Letzel, Marion; Licha, Tobias; Lyko, Sven; Miehe, Ulf; Sacher, Frank; Scheurer, Marco; Schmidt, Carsten K; Reemtsma, Thorsten; Ruhl, Aki Sebastian

    2015-04-01

    An increasing number of organic micropollutants (OMP) is detected in anthropogenically influenced water cycles. Source control and effective natural and technical barriers are essential to maintain a high quality of drinking water resources under these circumstances. Based on the literature and our own research this study proposes a limited number of OMP that can serve as indicator substances for the major sources of OMP, such as wastewater treatment plants, agriculture and surface runoff. Furthermore functional indicators are proposed that allow assessment of the proper function of natural and technical barriers in the aquatic environment, namely conventional municipal wastewater treatment, advanced treatment (ozonation, activated carbon), bank filtration and soil aquifer treatment as well as self-purification in surface water. These indicator substances include the artificial sweetener acesulfame, the anti-inflammatory drug ibuprofen, the anticonvulsant carbamazepine, the corrosion inhibitor benzotriazole and the herbicide mecoprop among others. The chemical indicator substances are intended to support comparisons between watersheds and technical and natural processes independent of specific water cycles and to reduce efforts and costs of chemical analyses without losing essential information.

  20. Method for improving dissolution efficiency in gas-absorption and liquid extraction processes

    DOEpatents

    Kanak, Brant E.; Stephenson, Michael J.

    1981-01-01

    This invention is a method for improving dissolution efficiency in processes in which a feed fluid is introduced to a zone where it is contacted with a liquid solvent for preferentially removing a component of the feed and where part of the solvent so contacted undergoes transfer into the feed fluid to saturate the same. It has been found that such transfer significantly impairs dissolution efficiency. In accordance with the invention, an amount of the above-mentioned solvent is added to the feed fluid being introduced to the contact zone, the solvent being added in an amount sufficient to effect reduction or elimination of the above-mentioned transfer. Preferably, the solvent is added to the feed fluid in an amount saturating or supersaturating the feed fluid under the conditions prevailing in the contact zone.

  1. Method for improving dissolution efficiency in gas-absorption and liquid extraction processes. [Patent application

    DOEpatents

    Kanak, B.E.; Stephenson, M.J.

    1980-01-11

    A method is described for improving dissolution efficiency in processes in which a feed fluid is introduced to a zone where it is contacted with a liquid solvent for preferentially removing a component of the feed and where part of the solvent so contacted undergoes transfer into the feed fluid to saturate the same. It has been found that such transfer significantly impairs dissolution efficiency. In accordance with the invention, an amount of the above-mentioned solvent is added to the feed fluid being introduced to the contact zone, the solvent being added in an amount sufficient to effect reduction or elimination of the above-mentioned transfer. Preferably, the solvent is added to the feed fluid in an amount saturating or supersaturating the feed fluid under the conditions prevailing in the contact zone.

  2. Effects of process variation in short cycle stretch forming in beverage can production

    NASA Astrophysics Data System (ADS)

    Schneider, Matthias; Liewald, Mathias

    2016-10-01

    Short Cycle Stretch Forming (SCS) is an innovative stretch forming technology developed at the Institute for Metal Forming Technology (IFU) at the University of Stuttgart. The SCS technology combines plane pre-stretching and deep drawing operations within the same stroke of press ram. Material is yielding from the inner to the outer part of the sheet. The sheet thickness is reduced and denting resistance and yield stress are increased due to hardening effects. SCS-Technology is enhanced due to rotational-symmetrical bodies by applying this technology to a cupping process in tinplate can production. A process simulation for SCS-Cupping processes was conducted. Based on these results a tool was manufactured and commissioned. Experimental results showed that material yields from the middle of the blank to the outer area of the cup wall. Due to the volume of material, the initial diameter can be reduced and material costs can be saved. In this paper different process settings and their effect on the amount of material, which yielded from the middle of the blank to its outside, are observed in a number of experimental series. A blank holder is added to the process in order to avoid wrinkling. The influence of this additional blank holder is therefore investigated in a first experimental set-up by varying blank holder force. In a further investigation the effects of two materials with different thicknesses is observed. Finally, an experimental series is conducted to observe the effect of blank diameter on the SCS-Cupping process. The results of this paper show that SCS-Cupping offers a promising potential for material savings and outline main effects for this technology.

  3. Life cycle assessment and nutrient analysis of various processing pathways in algal biofuel production.

    PubMed

    Mu, Dongyan; Ruan, Roger; Addy, Min; Mack, Sarah; Chen, Paul; Zhou, Yong

    2017-04-01

    This study focuses on analyzing nutrient distributions and environmental impacts of nutrient recycling, reusing, and discharging in algal biofuels production. The three biomass conversion pathways compared in this study were: hydrothermal liquefaction technology (HTL), hydrothermal hydrolysis pretreatment +HTL (HTP), and wet lipid extraction (WLE). Carbon, nitrogen, and phosphorous (C, N, P) flows were described in each pathway. A primary cost analysis was conducted to evaluate the economic performance. The LCA results show that the HTP reduced life cycle NOx emissions by 10% from HTL, but increased fossil fuel use, greenhouse gas emissions, and eutrophication potential by 14%, 5%, and 28% respectively. The cost of per gallon biodiesel produced in HTP was less than in HTL. To further reduce emissions, efforts should be focused on improving nutrient uptake rates in algae cultivation, increasing biomass carbon detention in hydrothermal hydrolysis, and/or enhancing biomass conversion rates in the biooil upgrading processes.

  4. Technological and life cycle assessment of organics processing odour control technologies.

    PubMed

    Bindra, Navin; Dubey, Brajesh; Dutta, Animesh

    2015-09-15

    As more municipalities and communities across developed world look towards implementing organic waste management programmes or upgrading existing ones, composting facilities are emerging as a popular choice. However, odour from these facilities continues to be one of the most important concerns in terms of cost & effective mitigation. This paper provides a technological and life cycle assessment of some of the different odour control technologies and treatment methods that can be implemented in organics processing facilities. The technological assessment compared biofilters, packed tower wet scrubbers, fine mist wet scrubbers, activated carbon adsorption, thermal oxidization, oxidization chemicals and masking agents. The technologies/treatment methods were evaluated and compared based on a variety of operational, usage and cost parameters. Based on the technological assessment it was found that, biofilters and packed bed wet scrubbers are the most applicable odour control technologies for use in organics processing faculties. A life cycle assessment was then done to compare the environmental impacts of the packed-bed wet scrubber system, organic (wood-chip media) bio-filter and inorganic (synthetic media) bio-filter systems. Twelve impact categories were assessed; cumulative energy demand (CED), climate change, human toxicity, photochemical oxidant formation, metal depletion, fossil depletion, terrestrial acidification, freshwater eutrophication, marine eutrophication, terrestrial eco-toxicity, freshwater eco-toxicity and marine eco-toxicity. The results showed that for all impact categories the synthetic media biofilter had the highest environmental impact, followed by the wood chip media bio-filter system. The packed-bed system had the lowest environmental impact for all categories.

  5. Identifying sources and processes controlling the sulphur cycle in the Canyon Creek watershed, Alberta, Canada.

    PubMed

    Nightingale, Michael; Mayer, Bernhard

    2012-01-01

    Sources and processes affecting the sulphur cycle in the Canyon Creek watershed in Alberta (Canada) were investigated. The catchment is important for water supply and recreational activities and is also a source of oil and natural gas. Water was collected from 10 locations along an 8 km stretch of Canyon Creek including three so-called sulphur pools, followed by the chemical and isotopic analyses on water and its major dissolved species. The δ(2)H and δ(18)O values of the water plotted near the regional meteoric water line, indicating a meteoric origin of the water and no contribution from deeper formation waters. Calcium, magnesium and bicarbonate were the dominant ions in the upstream portion of the watershed, whereas sulphate was the dominant anion in the water from the three sulphur pools. The isotopic composition of sulphate (δ(34)S and δ(18)O) revealed three major sulphate sources with distinct isotopic compositions throughout the catchment: (1) a combination of sulphate from soils and sulphide oxidation in the bedrock in the upper reaches of Canyon Creek; (2) sulphide oxidation in pyrite-rich shales in the lower reaches of Canyon Creek and (3) dissolution of Devonian anhydrite constituting the major sulphate source for the three sulphur pools in the central portion of the watershed. The presence of H(2)S in the sulphur pools with δ(34)S values ∼30 ‰ lower than those of sulphate further indicated the occurrence of bacterial (dissimilatory) sulphate reduction. This case study reveals that δ(34)S values of surface water systems can vary by more than 20 ‰ over short geographic distances and that isotope analyses are an effective tool to identify sources and processes that govern the sulphur cycle in watersheds.

  6. Subdiffusion-absorption process in a system consisting of two different media

    NASA Astrophysics Data System (ADS)

    Kosztołowicz, Tadeusz

    2017-02-01

    Subdiffusion with reaction A +B →B is considered in a system which consists of two homogeneous media joined together; the A particles are mobile, whereas B are static. Subdiffusion and reaction parameters, which are assumed to be independent of time and space variables, can be different in both media. Particles A move freely across the border between the media. In each part of the system, the process is described by the subdiffusion-reaction equations with fractional time derivative. By means of the method presented in this paper, we derive both the fundamental solutions (the Green's functions) P(x, t) to the subdiffusion-reaction equations and the boundary conditions at the border between the media. One of the conditions demands the continuity of a flux and the other one contains the Riemann-Liouville fractional time derivatives ∂α1P (0+,t ) /∂tα1 =(D1/D2 ) ∂α2P (0-,t ) /∂tα2 , where the subdiffusion parameters α1, D1 and α2, D2 are defined in the regions x <0 and x >0 , respectively.

  7. Dry injection flue gas desulfurization process using absorptive soda ash sorbent

    SciTech Connect

    Cyran, M.J.; Copenhafer, W.C.

    1986-05-13

    A dry injection flue gas desulfurization process is described which comprises injecting a dry soda ash sorbent, which is a particulate solid derived from calcination under non-sintering conditions of a NaHCO/sub 3/-containing compound, into a SO/sub 2/-contaminated flue gas stream that contains moisture in an amount of 0.5-10 wt% H/sub 2/O and is at a temperature of 100/sup 0/-175/sup 0/C; providing an amount of injected sorbent and sufficient gas-sorbent contact time such that a substantial portion, at least 40%, of the sorbent sodium content is utilized at NSR=1, in reducing the concentration of SO/sub 2/ in the gas stream, collecting the sorbent in a solids-collection device which is a fabric filter baghouse or an electrostatic precipitator; discharging collected sorbent from the solids-collection device; the dry soda ash sorbent being a porous calcine obtained from calcination of sodium sesquicarbonate, sodium bicarbonate, Wegscheider's salt or mixtures of these, and further characterized by having a minimum surface area of at least 2 m/sup 2//g and a residual bicarbonate content of less than 10 wt% NaHCO/sub 3/.

  8. Subdiffusion-absorption process in a system consisting of two different media.

    PubMed

    Kosztołowicz, Tadeusz

    2017-02-28

    Subdiffusion with reaction A+B→B is considered in a system which consists of two homogeneous media joined together; the A particles are mobile, whereas B are static. Subdiffusion and reaction parameters, which are assumed to be independent of time and space variables, can be different in both media. Particles A move freely across the border between the media. In each part of the system, the process is described by the subdiffusion-reaction equations with fractional time derivative. By means of the method presented in this paper, we derive both the fundamental solutions (the Green's functions) P(x, t) to the subdiffusion-reaction equations and the boundary conditions at the border between the media. One of the conditions demands the continuity of a flux and the other one contains the Riemann-Liouville fractional time derivatives ∂(α1) P(0(+),t)/∂t(α1) =(D1/D2)∂(α2) P(0(-),t)/∂t(α2) , where the subdiffusion parameters α1, D1 and α2, D2 are defined in the regions x<0 and x>0, respectively.

  9. Effect of Processing Route on Strain Controlled Low Cycle Fatigue Behavior of Polycrystalline NiAl

    NASA Technical Reports Server (NTRS)

    Rao, K. Bhanu Sankara; Lerch, B. A.; Noebe, R. D.

    1995-01-01

    The present investigation examines the effects of manufacturing process on the total axial strain controlled low cycle fatigue behavior of polycrystalline NiAl at 1000 K, a temperature above the monotonic Brittle-to-Ductile Transition Temperature (BDTT). The nickel aluminide samples were produced by three different processing routes: hot isostatic pressing of pre- alloyed powders, extrusion of prealloyed powders, and extrusion of vacuum induction melted ingots. The LCF behavior of the cast plus extruded material was also determined at room temperature (below the BD77) for comparison to the high temperature data. The cyclic stress response, cyclic stress-strain behavior, and strain-life relationships were influenced by the alloy preparation technique and the testing temperature. Detailed characterization of the LCF tested samples was conducted by optical and electron microscopy to determine the variations in fracture and deformation modes and to determine any microstructural changes that occurred during LCF testing. The dependence of LCF properties on processing route was rationalized on the basis of starting microstructure, brittle-to-ductile transition temperature, deformation induced changes in the basic microstructure, deformation substructure, and synergistic interaction between the damage modes.

  10. Functional genes to assess nitrogen cycling and aromatic hydrocarbon degradation: primers and processing matter

    PubMed Central

    Penton, C. Ryan; Johnson, Timothy A.; Quensen, John F.; Iwai, Shoko; Cole, James R.; Tiedje, James M.

    2013-01-01

    Targeting sequencing to genes involved in key environmental processes, i.e., ecofunctional genes, provides an opportunity to sample nature's gene guilds to greater depth and help link community structure to process-level outcomes. Vastly different approaches have been implemented for sequence processing and, ultimately, for taxonomic placement of these gene reads. The overall quality of next generation sequence analysis of functional genes is dependent on multiple steps and assumptions of unknown diversity. To illustrate current issues surrounding amplicon read processing we provide examples for three ecofunctional gene groups. A combination of in silico, environmental and cultured strain sequences was used to test new primers targeting the dioxin and dibenzofuran degrading genes dxnA1, dbfA1, and carAa. The majority of obtained environmental sequences were classified into novel sequence clusters, illustrating the discovery value of the approach. For the nitrite reductase step in denitrification, the well-known nirK primers exhibited deficiencies in reference database coverage, illustrating the need to refine primer-binding sites and/or to design multiple primers, while nirS primers exhibited bias against five phyla. Amino acid-based OTU clustering of these two N-cycle genes from soil samples yielded only 114 unique nirK and 45 unique nirS genus-level groupings, likely a reflection of constricted primer coverage. Finally, supervised and non-supervised OTU analysis methods were compared using the nifH gene of nitrogen fixation, with generally similar outcomes, but the clustering (non-supervised) method yielded higher diversity estimates and stronger site-based differences. High throughput amplicon sequencing can provide inexpensive and rapid access to nature's related sequences by circumventing the culturing barrier, but each unique gene requires individual considerations in terms of primer design and sequence processing and classification. PMID:24062736

  11. Bench-Scale Development of a Hot Carbonate Absorption Process with Crystallization-Enabled High Pressure Stripping for Post-Combustion CO{sub 2} Capture

    SciTech Connect

    Lu, Yongqi

    2014-02-01

    This report summarizes the methodology and preliminary results of a techno-economic analysis on a hot carbonate absorption process (Hot-CAP) with crystallization-enabled high pressure stripping for post-combustion CO{sub 2} capture (PCC). This analysis was based on the Hot-CAP that is fully integrated with a sub-critical steam cycle, pulverized coal-fired power plant adopted in Case 10 of the DOE/NETL’s Cost and Performance Baseline for Fossil Energy Plants. The techno-economic analysis addressed several important aspects of the Hot-CAP for PCC application, including process design and simulation, equipment sizing, technical risk and mitigation strategy, performance evaluation, and cost analysis. Results show that the net power produced in the subcritical power plant equipped with Hot-CAP is 611 MWe, greater than that with Econoamine (550 MWe). The total capital cost for the Hot-CAP, including CO{sub 2} compression, is $399 million, less than that for the Econoamine PCC ($493 million). O&M costs for the power plant with Hot-CAP is $175 million annually, less than that with Econoamine ($178 million). The 20-year levelized cost of electricity (LCOE) for the power plant with Hot-CAP, including CO2 transportation and storage, is 119.4 mills/kWh, a 59% increase over that for the plant without CO2 capture. The LCOE increase caused by CO{sub 2} capture for the Hot-CAP is 31% lower than that for its Econoamine counterpart.

  12. Intestinal Absorption Mechanisms of Prenylated Flavonoids Present in the Heat-Processed Epimedium koreanum Nakai (Yin Yanghuo)

    PubMed Central

    Chen, Yan; Zhao, Yan Hong; Jia, Xiao Bin; Hu, Ming

    2008-01-01

    Purpose The purpose is to determine absorption mechanism of five bioactive prenylated flavonoids (baohuoside I, icariin, epimedine A, B, and C) present in heat-processed Epimedium koreanum Nakai (Yin Yanghuo). Methods Transport of five prenylated flavonoids present in heat-processed herbs were studied in the human intestinal Caco-2 model and the perfused rat intestinal model. Results In the perfused rat intestinal model, prenylated flavonoids with a monoglucosidic bond (e.g., icariin) was rapidly hydrolyzed into corresponding metabolites (e.g., baohuoside I). In the Caco-2 model, apical to basolateral permeability of a monoglycoside baohuoside I (1.46 ×10−6 cm/sec) was more than 2 folds greater than four prenylated flavonoids with 2 or more sugar moieties (<0.6×10−6 cm/sec). The slow apical to basolateral transport of baohuoside I was the result of efflux. This efflux was carrier-mediated and active since its transport was vectorial, concentration- and temperature-dependent with activation energies greater than 15 kcal/mol. Efflux of baohuoside I was significantly suppressed by inhibitors of BCRP and MRP2, whereas efflux of icariin was significantly inhibited only by p-glycoprotein inhibitor verapamil. Because YHH is often heat-processed for better efficacy, we determined and found the optimal condition for increasing contents of more bioavailable flavonoids (i.e., baohuoside I) to be 160–170°C for 5–7 min. Conclusions Poor bioavailability of prenylated flavonoids results from their poor intrinsic permeation and transporter-mediated efflux. Heat processing parameters may be optimized to preserve the herb’s bioavailable flavonoids, which help retain and improve its efficacy during processing. PMID:18459036

  13. Light absorption processes and optimization of ZnO/CdTe core-shell nanowire arrays for nanostructured solar cells.

    PubMed

    Michallon, Jérôme; Bucci, Davide; Morand, Alain; Zanuccoli, Mauro; Consonni, Vincent; Kaminski-Cachopo, Anne

    2015-02-20

    The absorption processes of extremely thin absorber solar cells based on ZnO/CdTe core-shell nanowire (NW) arrays with square, hexagonal or triangular arrangements are investigated through systematic computations of the ideal short-circuit current density using three-dimensional rigorous coupled wave analysis. The geometrical dimensions are optimized for optically designing these solar cells: the optimal NW diameter, height and array period are of 200 ± 10 nm, 1-3 μm and 350-400 nm for the square arrangement with CdTe shell thickness of 40-60 nm. The effects of the CdTe shell thickness on the absorption of ZnO/CdTe NW arrays are revealed through the study of two optical key modes: the first one is confining the light into individual NWs, the second one is strongly interacting with the NW arrangement. It is also shown that the reflectivity of the substrate can improve Fabry-Perot resonances within the NWs: the ideal short-circuit current density is increased by 10% for the ZnO/fluorine-doped tin oxide (FTO)/ideal reflector as compared to the ZnO/FTO/glass substrate. Furthermore, the optimized square arrangement absorbs light more efficiently than both optimized hexagonal and triangular arrangements. Eventually, the enhancement factor of the ideal short-circuit current density is calculated as high as 1.72 with respect to planar layers, showing the high optical potentiality of ZnO/CdTe core-shell NW arrays.

  14. Thermochemical water-splitting cycle, bench-scale investigations and process engineering. Annual report, October 1, 1978-September 30, 1979

    SciTech Connect

    Caprioglio, G.; McCorkle, K.H.; Besenbruch, G.E.; Rode, J.S.

    1980-03-01

    A program to investigate thermochemical water splitting has been under way at General Atomic Company (GA) since October 1972. This document is an annual progress report of Department of Energy (DOE) sponsored process development work on the GA sulfur-iodine thermochemical water splitting cycle. The work consisted of laboratory bench-scale investigations, demonstration of the process in a closed-loop cycle demonstrator, and process engineering design studies. A bench-scale system, consisting of three subunits, has been designed to study the cycle under continuous flow conditions. The designs of subunit I, which models the main solution reaction and product separation, and subunit II, which models the concentration and decomposition of sulfuric acid, were presented in an earlier annual report. The design of subunit III, which models the purification and decomposition of hydrogen iodide, is given in this report. Progress on the installation and operation of subunits I and II is described. A closed-loop cycle demonstrator was installed and operated based on a DOE request. Operation of the GA sulfur-iodine cycle was demonstrated in this system under recycle conditions. The process engineering addresses the flowsheet design of a large-scale production process consisting of four chemical sections (I through IV) and one helium heat supply section (V). The completed designs for sections I through V are presented. The thermal efficiency of the process calculated from the present flowsheet is 47%.

  15. Evaluation of Boundless Biogeochemical Cycle through Development of Process-Based Eco-Hydrological and Biogeochemical Cycle Model to Incorporate Terrestrial-Aquatic Continuum

    NASA Astrophysics Data System (ADS)

    Nakayama, T.; Maksyutov, S. S.

    2014-12-01

    Inland water might act as important transport pathway for continental biogeochemical cycle although its contribution has remained uncertain yet due to a paucity of data (Battin et al. 2009). The author has developed process-based National Integrated Catchment-based Eco-hydrology (NICE) model (Nakayama, 2008a-b, 2010, 2011a-b, 2012a-c, 2013; Nakayama and Fujita, 2010; Nakayama and Hashimoto, 2011; Nakayama and Shankman, 2013a-b; Nakayama and Watanabe, 2004, 2006, 2008a-b; Nakayama et al., 2006, 2007, 2010, 2012), which incorporates surface-groundwater interactions, includes up- and down-scaling processes between local-regional-global scales, and can simulate iteratively nonlinear feedback between hydrologic-geomorphic-ecological processes. Because NICE incorporates 3-D groundwater sub-model and expands from previous 1- or 2-D or steady state, the model can simulate the lateral transport pronounced at steeper-slope or riparian/floodplain with surface-groundwater connectivity. River discharge and groundwater level simulated by NICE agreed reasonably with those in previous researches (Niu et al., 2007; Fan et al., 2013) and extended to clarify lateral subsurface also has important role on global hydrologic cycle (Nakayama, 2011b; Nakayama and Shankman, 2013b) though the resolution was coarser. NICE was further developed to incorporate biogeochemical cycle including reaction between inorganic and organic carbons in terrestrial and aquatic ecosystems. The missing role of carbon cycle simulated by NICE, for example, CO2 evasion from inland water (global total flux was estimated as about 1.0 PgC/yr), was relatively in good agreement in that estimated by empirical relation using previous pCO2 data (Aufdenkampe et al., 2011; Laruelle et al., 2013). The model would play important role in identification of greenhouse gas balance of the biosphere and spatio-temporal hot spots, and bridging gap between top-down and bottom-up approaches (Cole et al. 2007; Frei et al. 2012).

  16. Ideal thermodynamic processes of oscillatory-flow regenerative engines will go to ideal stirling cycle?

    NASA Astrophysics Data System (ADS)

    Luo, Ercang

    2012-06-01

    This paper analyzes the thermodynamic cycle of oscillating-flow regenerative machines. Unlike the classical analysis of thermodynamic textbooks, the assumptions for pistons' movement limitations are not needed and only ideal flowing and heat transfer should be maintained in our present analysis. Under such simple assumptions, the meso-scale thermodynamic cycles of each gas parcel in typical locations of a regenerator are analyzed. It is observed that the gas parcels in the regenerator undergo Lorentz cycle in different temperature levels, whereas the locus of all gas parcels inside the regenerator is the Ericson-like thermodynamic cycle. Based on this new finding, the author argued that ideal oscillating-flow machines without heat transfer and flowing losses is not the Stirling cycle. However, this new thermodynamic cycle can still achieve the same efficiency of the Carnot heat engine and can be considered a new reversible thermodynamic cycle under two constant-temperature heat sinks.

  17. A new biological phosphorus removal process in association with sulfur cycle.

    PubMed

    Wu, Di; Ekama, George A; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2013-06-01

    Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production. This study seeks to expand the SANI process into an enhanced biological phosphorus removal (EBPR) process. A sulfur cycle associated EBPR was explored in an alternating anaerobic/oxygen-limited aerobic sequencing batch reactor with acetate fed as sole electron donor and sulfate as sulfur source at a total organic carbon to sulfur ratio of 1.1-3.1 (mg C/mg S). Phosphate uptake and polyphosphate formation was observed in this reactor that sustained high phosphate removal (20 mg P/L removed with 320 mg COD/L). This new EBPR process was supported by six observations: 1) anaerobic phosphate release associated with acetate uptake, poly-phosphate hydrolysis, poly-hydroxyalkanoate (PHA) (and poly-S(2-)/S(0)) formation and an "aerobic" phosphate uptake associated with PHA (and poly-S(2-)/S(0)) degradation, and polyphosphate formation; 2) a high P/VSS ratio (>0.16 mg P/mg VSS) and an associated low VSS/TSS ratio (0.75) characteristic of conventional PAOs; 3) a lack of P-release and P-uptake with formaldehyde inactivation and autoclaved sterilized biomass; 4) an absence of chemical precipitated P crystals as determined by XRD analysis; 5) a sludge P of more than 90% polyphosphate as determined by sequential P extraction; and 6) microscopically, observed PHA, poly-P and S globules in the biomass. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Life cycle assessment of microalgae to biofuel: Thermochemical processing through hydrothermal liquefaction or pyrolysis

    NASA Astrophysics Data System (ADS)

    Bennion, Edward P.

    Microalgae are currently being investigated as a renewable transportation fuel feedstock based on various advantages that include high annual yields, utilization of poor quality land, does not compete with food, and can be integrated with various waste streams. This study focuses on directly assessing the impact of two different thermochemical conversion technologies on the microalgae-to-biofuel process through life cycle assessment. A system boundary of a "well to pump" (WTP) is defined and includes sub-process models of the growth, dewatering, thermochemical bio-oil recovery, bio-oil stabilization, conversion to renewable diesel, and transport to the pump. Models were validated with experimental and literature data and are representative of an industrial-scale microalgae-to-biofuel process. Two different thermochemical bio-oil conversion systems are modeled and compared on a systems level, hydrothermal liquefaction (HTL) and pyrolysis. The environmental impact of the two pathways were quantified on the metrics of net energy ratio (NER), defined here as energy consumed over energy produced, and greenhouse gas (GHG) emissions. Results for WTP biofuel production through the HTL pathway were determined to be 1.23 for the NER and GHG emissions of -11.4 g CO2 eq (MJ renewable diesel)-1. WTP biofuel production through the pyrolysis pathway results in a NER of 2.27 and GHG emissions of 210 g CO2 eq (MJ renewable diesel)-1. The large environmental impact associated with the pyrolysis pathway is attributed to feedstock drying requirements and combustion of co-products to improve system energetics. Discussion focuses on a detailed breakdown of the overall process energetics and GHGs, impact of modeling at laboratory-scale compared to industrial-scale, environmental impact sensitivity to engineering systems input parameters for future focused research and development, and a comparison of results to literature.

  19. The process of processing: exploring the validity of Neisser's perceptual cycle model with accounts from critical decision-making in the cockpit.

    PubMed

    Plant, Katherine L; Stanton, Neville A

    2015-01-01

    The perceptual cycle model (PCM) has been widely applied in ergonomics research in domains including road, rail and aviation. The PCM assumes that information processing occurs in a cyclical manner drawing on top-down and bottom-up influences to produce perceptual exploration and actions. However, the validity of the model has not been addressed. This paper explores the construct validity of the PCM in the context of aeronautical decision-making. The critical decision method was used to interview 20 helicopter pilots about critical decision-making. The data were qualitatively analysed using an established coding scheme, and composite PCMs for incident phases were constructed. It was found that the PCM provided a mutually exclusive and exhaustive classification of the information-processing cycles for dealing with critical incidents. However, a counter-cycle was also discovered which has been attributed to skill-based behaviour, characteristic of experts. The practical applications and future research questions are discussed. Practitioner Summary: This paper explores whether information processing, when dealing with critical incidents, occurs in the manner anticipated by the perceptual cycle model. In addition to the traditional processing cycle, a reciprocal counter-cycle was found. This research can be utilised by those who use the model as an accident analysis framework.

  20. Oxygen Sensitivity of Anammox and Coupled N-Cycle Processes in Oxygen Minimum Zones

    PubMed Central

    Kalvelage, Tim; Jensen, Marlene M.; Contreras, Sergio; Revsbech, Niels Peter; Lam, Phyllis; Günter, Marcel; LaRoche, Julie; Lavik, Gaute; Kuypers, Marcel M. M.

    2011-01-01

    Nutrient measurements indicate that 30–50% of the total nitrogen (N) loss in the ocean occurs in oxygen minimum zones (OMZs). This pelagic N-removal takes place within only ∼0.1% of the ocean volume, hence moderate variations in the extent of OMZs due to global warming may have a large impact on the global N-cycle. We examined the effect of oxygen (O2) on anammox, NH3 oxidation and NO3− reduction in 15N-labeling experiments with varying O2 concentrations (0–25 µmol L−1) in the Namibian and Peruvian OMZs. Our results show that O2 is a major controlling factor for anammox activity in OMZ waters. Based on our O2 assays we estimate the upper limit for anammox to be ∼20 µmol L−1. In contrast, NH3 oxidation to NO2− and NO3− reduction to NO2− as the main NH4+ and NO2− sources for anammox were only moderately affected by changing O2 concentrations. Intriguingly, aerobic NH3 oxidation was active at non-detectable concentrations of O2, while anaerobic NO3− reduction was fully active up to at least 25 µmol L−1 O2. Hence, aerobic and anaerobic N-cycle pathways in OMZs can co-occur over a larger range of O2 concentrations than previously assumed. The zone where N-loss can occur is primarily controlled by the O2-sensitivity of anammox itself, and not by any effects of O2 on the tightly coupled pathways of aerobic NH3 oxidation and NO3− reduction. With anammox bacteria in the marine environment being active at O2 levels ∼20 times higher than those known to inhibit their cultured counterparts, the oceanic volume potentially acting as a N-sink increases tenfold. The predicted expansion of OMZs may enlarge this volume even further. Our study provides the first robust estimates of O2 sensitivities for processes directly and indirectly connected with N-loss. These are essential to assess the effects of ocean de-oxygenation on oceanic N-cycling. PMID:22216239

  1. Oxygen sensitivity of anammox and coupled N-cycle processes in oxygen minimum zones.

    PubMed

    Kalvelage, Tim; Jensen, Marlene M; Contreras, Sergio; Revsbech, Niels Peter; Lam, Phyllis; Günter, Marcel; LaRoche, Julie; Lavik, Gaute; Kuypers, Marcel M M

    2011-01-01

    Nutrient measurements indicate that 30-50% of the total nitrogen (N) loss in the ocean occurs in oxygen minimum zones (OMZs). This pelagic N-removal takes place within only ~0.1% of the ocean volume, hence moderate variations in the extent of OMZs due to global warming may have a large impact on the global N-cycle. We examined the effect of oxygen (O(2)) on anammox, NH(3) oxidation and NO(3)(-) reduction in (15)N-labeling experiments with varying O(2) concentrations (0-25 µmol L(-1)) in the Namibian and Peruvian OMZs. Our results show that O(2) is a major controlling factor for anammox activity in OMZ waters. Based on our O(2) assays we estimate the upper limit for anammox to be ~20 µmol L(-1). In contrast, NH(3) oxidation to NO(2)(-) and NO(3)(-) reduction to NO(2)(-) as the main NH(4)(+) and NO(2)(-) sources for anammox were only moderately affected by changing O(2) concentrations. Intriguingly, aerobic NH(3) oxidation was active at non-detectable concentrations of O(2), while anaerobic NO(3)(-) reduction was fully active up to at least 25 µmol L(-1) O(2). Hence, aerobic and anaerobic N-cycle pathways in OMZs can co-occur over a larger range of O(2) concentrations than previously assumed. The zone where N-loss can occur is primarily controlled by the O(2)-sensitivity of anammox itself, and not by any effects of O(2) on the tightly coupled pathways of aerobic NH(3) oxidation and NO(3)(-) reduction. With anammox bacteria in the marine environment being active at O(2) levels ~20 times higher than those known to inhibit their cultured counterparts, the oceanic volume potentially acting as a N-sink increases tenfold. The predicted expansion of OMZs may enlarge this volume even further. Our study provides the first robust estimates of O(2) sensitivities for processes directly and indirectly connected with N-loss. These are essential to assess the effects of ocean de-oxygenation on oceanic N-cycling. © 2011 Kalvelage et al.

  2. Application of online UV absorption measurements for ozone process control in secondary effluent with variable nitrite concentration.

    PubMed

    Stapf, Michael; Miehe, Ulf; Jekel, Martin

    2016-11-01

    Ozone process control in secondary effluent used for elimination of trace organic compounds (TrOCs) requires the use of surrogates, such as the relative reduction of UV absorption at 254 nm (ΔUVA254) to adapt the ozone dose to a varying water quality. In the present study, a closed-loop process control based on two online UVA254 measurements was successfully implemented and tested under realistic conditions with ozone doses from 0.2 to 1.05 mg-O3/mg-DOC at a pilot scale ozonation system with subsequent coagulation filtration at a municipal wastewater treatment plant (DOC ∼ 13 mg/L, UVA254 ∼ 27 m(-1), and nitrite peaks of up to 1.6 mg-N/L). It could be shown that measuring the UVA254 at the ozonation effluent was superior to the measurement of UVA254 at the filter effluent in terms of response time due to changes in water quality, whereas online measurement at the filter effluent showed a better agreement with laboratory data and a reduced maintenance interval due to less particles. Additional online nitrite measurement is not necessary as the ozone consumption by nitrite directly impacts ΔUVA254.

  3. A meta-analysis of oceanic DMS and DMSP cycling processes: Disentangling the summer paradox

    NASA Astrophysics Data System (ADS)

    Galí, Martí; Simó, Rafel

    2015-04-01

    The biogenic volatile compound dimethylsulfide (DMS) is produced in the ocean mainly from the ubiquitous phytoplankton osmolyte dimethylsulfoniopropionate (DMSP). In the upper mixed layer, DMS concentration and the daily averaged solar irradiance are roughly proportional across latitudes and seasons. This translates into a seasonal mismatch between DMS and phytoplankton biomass at low latitudes, termed the "DMS summer paradox," which remains difficult to reproduce with biogeochemical models. Here we report on a global meta-analysis of DMSP and DMS cycling processes and their relationship to environmental factors. We show that DMS seasonality reflects progressive changes in a short-term dynamic equilibrium, set by the quotient between gross DMS production rates and the sum of biotic and abiotic DMS consumption rate constants. Gross DMS production is the principal driver of DMS seasonality, due to the synergistic increases toward summer in two of its underlying factors: phytoplankton DMSP content (linked to species succession) and short-term community DMSP-to-DMS conversion yields (linked to physiological stress). We also show that particulate DMSP transformations (linked to grazing-induced phytoplankton mortality) generally contribute a larger share of gross DMS production than dissolved-phase DMSP metabolism. The summer paradox is amplified by a decrease in microbial DMS consumption rate constants toward summer. However, this effect is partially compensated by a concomitant increase in abiotic DMS loss rate constants. Besides seasonality, we identify consistent covariation between key sulfur cycling variables and trophic status. These findings should improve the modeling projections of the main natural source of climatically active atmospheric sulfur.

  4. An amorphous silicon photodiode with 2 THz gain-bandwidth product based on cycling excitation process

    NASA Astrophysics Data System (ADS)

    Yan, Lujiang; Yu, Yugang; Zhang, Alex Ce; Hall, David; Niaz, Iftikhar Ahmad; Raihan Miah, Mohammad Abu; Liu, Yu-Hsin; Lo, Yu-Hwa

    2017-09-01

    Since impact ionization was observed in semiconductors over half a century ago, avalanche photodiodes (APDs) using impact ionization in a fashion of chain reaction have been the most sensitive semiconductor photodetectors. However, APDs have relatively high excess noise, a limited gain-bandwidth product, and high operation voltage, presenting a need for alternative signal amplification mechanisms of superior properties. As an amplification mechanism, the cycling excitation process (CEP) was recently reported in a silicon p-n junction with subtle control and balance of the impurity levels and profiles. Realizing that CEP effect depends on Auger excitation involving localized states, we made the counter intuitive hypothesis that disordered materials, such as amorphous silicon, with their abundant localized states, can produce strong CEP effects with high gain and speed at low noise, despite their extremely low mobility and large number of defects. Here, we demonstrate an amorphous silicon low noise photodiode with gain-bandwidth product of over 2 THz, based on a very simple structure. This work will impact a wide range of applications involving optical detection because amorphous silicon, as the primary gain medium, is a low-cost, easy-to-process material that can be formed on many kinds of rigid or flexible substrates.

  5. [Sulfate reduction and microbial processes of the methane cycle in the sediments of the Sevastopol bay].

    PubMed

    Pimenov, N V; Egorov, V N; Kanapatskiĭ, T A; Malakhova, T V; Artemov, Iu G; Sigalevich, P A; Malakhova, L V

    2013-01-01

    The rates of microbial processes of sulfate reduction and of the methane cycle were measured in the bottom sediments of the Sevastopol basin, where seeps of gaseous methane have been previously found. Typically for marine environments, sulfate reduction played the major role in the terminal phase of decomposition of organic matter (OM) in reduced sediments of this area. The rate of this process depended on the amount of available OM. The rate of methanogenesis in the sediments increased with depth, peaking in the subsurface horizons, where decreased sulfate concentration was detected in the pore water. The highest rates of sulfate-dependent anaerobic methane oxidation were found close to the methane-sulfate transition zone as is typical of most investigated marine sediments. The data on the carbon isotopic composition of gaseous methane from the seeps and dissolved CH4 from the bottom sediments, as well as on the rates of microbial methanogenesis and methane oxidation indicate that the activity of the methane seeps results from accumulation of biogenic methane in the cavities of the underlying geological structures with subsequent periodic release of methane bubbles into the water column.

  6. Environmental and economic life cycle assessment for sewage sludge treatment processes in Japan.

    PubMed

    Hong, Jinglan; Hong, Jingmin; Otaki, Masahiro; Jolliet, Olivier

    2009-02-01

    Life cycle assessment for sewage sludge treatment was carried out by estimating the environmental and economic impacts of the six alternative scenarios most often used in Japan: dewatering, composting, drying, incineration, incinerated ash melting and dewatered sludge melting, each with or without digestion. Three end-of-life treatments were also studied: landfilling, agricultural application and building material application. The results demonstrate that sewage sludge digestion can reduce the environmental load and cost through reduced dry matter volume. The global warming potential (GWP) generated from incineration and melting processes can be significantly reduced through the reuse of waste heat for electricity and/or heat generation. Equipment production in scenarios except dewatering has an important effect on GWP, whereas the contribution of construction is negligible. In addition, the results show that the dewatering scenario has the highest impact on land use and cost, the drying scenario has the highest impact on GWP and acidification, and the incinerated ash melting scenario has the highest impact on human toxicity due to re-emissions of heavy metals from incinerated ash in the melting unit process. On the contrary, the dewatering, composting and incineration scenarios generate the lowest impact on human toxicity, land use and acidification, respectively, and the incinerated ash melting scenario has the lowest impact on GWP and cost. Heavy metals released from atmospheric effluents generated the highest human toxicity impact, with the effect of dioxin emissions being significantly lower. This study proved that the dewatered sludge melting scenario is an environmentally optimal and economically affordable method.

  7. Life cycle assessment of oriented strand boards (OSB): from process innovation to ecodesign.

    PubMed

    Benetto, Enrico; Becker, Marko; Welfring, Joëlle

    2009-08-01

    Oriented strand boards (OSBs) are wood panels that are used worldwide mainly in the packaging and the building sectors. Their market share is rapidly increasing thanks to their outstanding mechanical properties and to a renewed interest for wood based products. The OSB production process generates, nonetheless, emissions of volatile organic compounds (VOCs) during the air-drying of wood strands. This known problem in the literature leads to an odorous nuisance in the surrounding area of the production site. In order to address this problem, a novel application to wood drying of an innovative vapor drying technology is successfully operated at the production site of Kronospan Luxembourg S.A. In addition to the reduced odorous nuisance, a significant environmental added value is expected because of the other modifications induced by the vapor-drying technique on the OSB production process viz. the reduced energy and raw materials demands and the change of adhesive mixture, with the addition of phenol resin. The potential impact of this technology on the OSB market is therefore very significant. This study was aimed at assessing the environmental added value provided by the vapor-drying technique through a life cycle assessment (LCA) according to ISO 14040-44 standards. The objective was to compare the environmental performances of the former and the current OSB production processes. Considering only the pollutant emissions from the OSB production process, the reduction of climate change impact and human health damage is significant respectively, 15-20% and 50-75%. When the lifecycle processes related to the OSB production are included, the reduction of damages does not exceed 3-7%. Following an uncertainty analysis,this reduction was nevertheless proven to be statistically significant. However, it is observed that the reduction of environmental impacts and damages allowed by the vapor-drying technology is counterbalanced by the change of adhesive mixture. Indeed the

  8. Integration of the AVLIS (atomic vapor laser isotopic separation) process into the nuclear fuel cycle. [Effect of AVLIS feed requirements on overall fuel cycle

    SciTech Connect

    Hargrove, R.S.; Knighton, J.B.; Eby, R.S.; Pashley, J.H.; Norman, R.E.

    1986-08-01

    AVLIS RD and D efforts are currently proceeding toward full-scale integrated enrichment demonstrations in the late 1980's and potential plant deployment in the mid 1990's. Since AVLIS requires a uranium metal feed and produces an enriched uranium metal product, some change in current uranium processing practices are necessitated. AVLIS could operate with a UF/sub 6/-in UF/sub 6/-out interface with little effect to the remainder of the fuel cycle. This path, however, does not allow electric utility customers to realize the full potential of low cost AVLIS enrichment. Several alternative processing methods have been identified and evaluated which appear to provide opportunities to make substantial cost savings in the overall fuel cycle. These alternatives involve varying levels of RD and D resources, calendar time, and technical risk to implement and provide these cost reduction opportunities. Both feed conversion contracts and fuel fabricator contracts are long-term entities. Because of these factors, it is not too early to start planning and making decisions on the most advantageous options so that AVLIS can be integrated cost effectively into the fuel cycle. This should offer economic opportunity to all parties involved including DOE, utilities, feed converters, and fuel fabricators. 10 refs., 11 figs., 2 tabs.

  9. CO2 Capture from Flue Gas by Phase Transitional Absorption

    SciTech Connect

    Liang Hu

    2009-06-30

    A novel absorption process called Phase Transitional Absorption was invented. What is the Phase Transitional Absorption? Phase Transitional Absorption is a two or multi phase absorption system, CO{sub 2} rich phase and CO{sub 2} lean phase. During Absorption, CO{sub 2} is accumulated in CO{sub 2} rich phase. After separating the two phases, CO{sub 2} rich phase is forward to regeneration. After regeneration, the regenerated CO{sub 2} rich phase combines CO{sub 2} lean phase to form absorbent again to complete the cycle. The advantage for Phase Transitional Absorption is obvious, significantly saving on regeneration energy. Because CO{sub 2} lean phase was separated before regeneration, only CO{sub 2} rich phase was forward to regeneration. The absorption system we developed has the features of high absorption rate, high loading and working capacity, low corrosion, low regeneration heat, no toxic to environment, etc. The process evaluation shows that our process is able to save 80% energy cost by comparing with MEA process.

  10. Impact of co-administration of protonated nanostructured aluminum silicate (cholesterol absorption inhibitor) on the absorption of lipid soluble vitamins D3 and K1: an assessment of pharmacokinetic and in vitro intraluminal processing.

    PubMed

    Ibrahim, Fady; Sivak, Olena; Wong, Carly; Hopkins, Patrick; Midha, Ankur; Gordon, Jacob; Darlington, Jerald W; Wasan, Kishor M

    2013-05-13

    Protonated nanostructured aluminum silicate (NSAS) is a protonated montmorillonite clay that was shown to be effective as an inhibitor of intestinal cholesterol absorption. The effect of NSAS on the intestinal absorption of nutrients is unknown. An in vitro lipolysis model was adapted to test the intraluminal processing of vitamin D3 and K1 in the presence of various amounts of NSAS. Additionally, vitamin absorption was assessed in male Sprague-Dawley rats randomized in the following treatment groups: IV administration of 0.1 mg/kg vitamin D3 and 1 mg/kg vitamin K1, and a single-dose gavage of 1 mg/kg vitamin D3 and 5mg/kg of vitamin K1 in peanut oil with various doses of NSAS slurry, 2% NSAS-fortified diet, or 50 mg/kg stigmastanol. The solubilized fraction of vitamin D3 in the lipolysis medium was reduced from 70% to 46% upon the addition of 120 mg NSAS. In contrast, the solubilized fractions of vitamin K1 were not significantly affected. Although the NSAS-fortified diet did not significantly affect the absorbed fraction of both vitamins, NSAS slurry decreased the absorption of vitamin D3 as compared to the control. These results indicate that NSAS may be incorporated in diet to treat hypercholesterolemia; however, vitamin D3 monitoring may be required. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Incorporating redox processes improves prediction of carbon and nutrient cycling and greenhouse gas emission

    NASA Astrophysics Data System (ADS)

    Tang, Guoping; Zheng, Jianqiu; Yang, Ziming; Graham, David; Gu, Baohua; Mayes, Melanie; Painter, Scott; Thornton, Peter

    2016-04-01

    Among the coupled thermal, hydrological, geochemical, and biological processes, redox processes play major roles in carbon and nutrient cycling and greenhouse gas (GHG) emission. Increasingly, mechanistic representation of redox processes is acknowledged as necessary for accurate prediction of GHG emission in the assessment of land-atmosphere interactions. Simple organic substrates, Fe reduction, microbial reactions, and the Windermere Humic Aqueous Model (WHAM) were added to a reaction network used in the land component of an Earth system model. In conjunction with this amended reaction network, various temperature response functions used in ecosystem models were assessed for their ability to describe experimental observations from incubation tests with arctic soils. Incorporation of Fe reduction reactions improves the prediction of the lag time between CO2 and CH4 accumulation. The inclusion of the WHAM model enables us to approximately simulate the initial pH drop due to organic acid accumulation and then a pH increase due to Fe reduction without parameter adjustment. The CLM4.0, CENTURY, and Ratkowsky temperature response functions better described the observations than the Q10 method, Arrhenius equation, and ROTH-C. As electron acceptors between O2 and CO2 (e.g., Fe(III), SO42-) are often involved, our results support inclusion of these redox reactions for accurate prediction of CH4 production and consumption. Ongoing work includes improving the parameterization of organic matter decomposition to produce simple organic substrates, examining the influence of redox potential on methanogenesis under thermodynamically favorable conditions, and refining temperature response representation near the freezing point by additional model-experiment iterations. We will use the model to describe observed GHG emission at arctic and tropical sites.

  12. The effect of gold mining and processing on biogeochemical cycles in Muteh area, Isfahan province, Iran

    NASA Astrophysics Data System (ADS)

    Keshavarzi, B.; Moore, F.

    2009-04-01

    The environmental impacts of gold mining and processing on geochemical and biogeochemical cycles in Muteh region located northwest of Esfahan province and northeast of Golpaygan city is investigated. For this purpose systematic sampling was carried out in, rock, soil, water, and sediment environments along with plant, livestocks and human hair samples. Mineralogical and Petrological studies show that ore mineral such as pyrite and arsenopyrite along with fluorine-bearing minerals like tremolite, actinolite, biotite and muscovite occur in green schist, amphibolite and lucogranitic rocks in the area. The hydrochemistry of the analysed water samples indicate that As and F display the highest concentrations among the analysed elements. Indeed arsenic has the highest concentration in both topsoil and subsoil samples when compared with other potentially toxic elements. Anthropogenic activity also have it s greatest effect on increasing arsenic concentration among the analysed samples. The concentration of the majority of the analysed elements in the shoots and leaves of two local plants of the region i.e Artemesia and Penagum is higher than their concentration in the roots. Generally speaking, Artemesia has a greater tendency for bioaccumulating heavy metals. The results of cyanide analysis in soil samples show that cyanide concentration in the soils near the newly built tailing dam is much higher than that in the vicinity of the old tailing dam. The high concentration of fluorine in the drinking water of the Muteh village is the main reason of the observed dental fluorosis symptoms seen in the inhabitants. One of the two drinking water wells which is located near the metamorphic complex and supplies part of the tap water in the village, probably has the greatest impact in this regard. A decreasing trend in fluorine concentration is illustrated with increasing distance from the metamorphic complex. Measurements of As concentration in human hair specimens indicate that As

  13. Advanced oxidation process based on the Cr(III)/Cr(VI) redox cycle.

    PubMed

    Bokare, Alok D; Choi, Wonyong

    2011-11-01

    Oxidative degradation of aqueous organic pollutants, using 4-chlorophenol (4-CP) as a main model substrate, was achieved with the concurrent H(2)O(2)-mediated transformation of Cr(III) to Cr(VI). The Fenton-like oxidation of 4-CP is initiated by the reaction between the aquo-complex of Cr(III) and H(2)O(2), which generates HO(•) along with the stepwise oxidation of Cr(III) to Cr(VI). The Cr(III)/H(2)O(2) system is inactive in acidic condition, but exhibits maximum oxidative capacity at neutral and near-alkaline pH. Since we previously reported that Cr(VI) can also activate H(2)O(2) to efficiently generate HO(•), the dual role of H(2)O(2) as an oxidant of Cr(III) and a reductant of Cr(VI) can be utilized to establish a redox cycle of Cr(III)-Cr(VI)-Cr(III). As a result, HO(•) can be generated using both Cr(III)/H(2)O(2) and Cr(VI)/H(2)O(2) reactions, either concurrently or sequentially. The formation of HO(•) was confirmed by monitoring the production of p-hydroxybenzoic acid from [benzoic acid + HO(•)] as a probe reaction and by quenching the degradation of 4-CP in the presence of methanol as a HO(•) scavenger. The oxidation rate of 4-CP in the Cr(III)/H(2)O(2) solution was highly influenced by pH, which is ascribed to the hydrolysis of Cr(III)(H(2)O)(n) into Cr(III)(H(2)O)(n-m)(OH)(m) and the subsequent condensation to oligomers. The present study proposes that the Cr(III)/H(2)O(2) combined with Cr(VI)/H(2)O(2) process is a viable advanced oxidation process that operates over a wide pH range using the reusable redox cycle of Cr(III) and Cr(VI).

  14. Advanced heat pump cycle

    SciTech Connect

    Groll, E.A.; Radermacher, R.

    1993-07-01

    The desorption and absorption process of a vapor compression heat pump with a solution circuit (VCHSC) proceeds at gliding temperature intervals, which can be adjusted over a wide range. In case that the gliding temperature intervals in the desorber and the absorber overlap, a modification of the VCHSC employing a desorber/absorber heat exchange (DAHX) can be introduced, which results in an extreme reduction of the pressure ratio. Although the DAHX-cycle has features of a two-stage cycle, it still requires only one solution pump, one separator and one compressor. Such a cycle for the working pair ammonia/water is built in the Energy Laboratory of the Center for Environmental Energy Engineering at the University of Maryland. The experimental results obtained with the research plant are discussed and compared to those calculated with a simulation program. The possible temperature lift between heat source and heat sink depending on the achievable COP are presented.

  15. Complex surface analytical investigations on hydrogen absorption and desorption processes of a TiMn2-based alloy.

    PubMed

    Schülke, Mark; Kiss, Gábor; Paulus, Hubert; Lammers, Martin; Ramachandran, Vaidyanath; Sankaran, Kannan; Müller, Karl-Heinz

    2009-04-01

    Metal hydrides are one of the most promising technologies in the field of hydrogen storage due to their high volumetric storage density. Important reaction steps take place at the very surface of the solid during hydrogen absorption. Since these reaction steps are drastically influenced by the properties and potential contamination of the solid, it is very important to understand the characteristics of the surface, and a variety of analytical methods are required to achieve this. In this work, a TiMn(2)-type metal hydride alloy is investigated by means of high-pressure activation measurements, X-ray photoelectron spectroscopy (XPS), secondary neutral mass spectrometry (SNMS) and thermal desorption mass spectrometry (TDMS). In particular, TDMS is an analytical tool that, in contrast to SIMS or SNMS, allows the hydrogen content in a metal to be quantified. Furthermore, it allows the activation energy for desorption to be determined from TDMS profiles; the method used to achieve this is presented here in detail. In the results section, it is shown that the oxide layer formed during manufacture and long-term storage prevents any hydrogen from being absorbed, and so an activation process is required. XPS measurements show the oxide states of the main alloy elements, and a layer 18 nm thick is determined via SNMS. Furthermore, defined oxide layers are produced and characterized in UHV using XPS. The influence of these thin oxide layers on the hydrogen sorption process is examined using TDMS. Finally, the activation energy of desorption is determined for the investigated alloy using the method presented here, and values of 46 kJ/mol for hydrogen sorbed in UHV and 103 kJ/mol for hydrogen originating from the manufacturing process are obtained.

  16. Quantum Interference between Energy Absorption Processes of Molecular Exciton and Interface Plasmons on Luminescence Induced by Scanning Tunneling Microscopy

    NASA Astrophysics Data System (ADS)

    Miwa, Kuniyuki; Imasa, Hiroshi; Sakaue, Mamoru; Kasai, Hideaki; Kim, Yousoo

    2015-03-01

    Luminescence induced by the tunneling current of a scanning tunneling microscope (STM) from molecule-covered metal surfaces is attributed to radiative decays of molecules and interface plasmons localized near the tip-substrate gap region. Since the dynamics of molecule and interface plasmons strongly influence each other, the interplay between these dynamics gives rise to peculiar phenomena originating from quantum many-body effects. In this study, we develop the effective model of the system and investigate the luminescence properties using the nonequilibrium Green's function method. The results show that, in addition to the dynamics of molecule, energy reabsorption by interface plasmons have a critical role in determining the luminescence spectral profile of interface plasmons. The additional peak structure arises owing to the interference between these energy absorption processes. Origin of prominent peak and dip structures observed in recent experiments are identified by the developed theory. The details of the interference effects on the luminescence properties will be discussed. This work was supported by JSPS KAKENHI Grant Number 26886013.

  17. [Removal of CO2 from simulated flue gas of power plants by membrane-based gas absorption processes].

    PubMed

    Yang, Ming-Fen; Fang, Meng-Xiang; Zhang, Wei-Feng; Wang, Shu-Yuan; Xu, Zhi-Kang; Luo, Zhong-Yang; Cen, Ke-Fa

    2005-07-01

    Three typical absorbents such as aqueous of aminoacetic acid potassium (AAAP), monoethanolamine (MEA) and methyldiethanolamine(MDEA) are selected to investigate the performance of CO2 separation from flue gas via membrane contactors made of hydrophobic hollow fiber polypropylene porous membrane. Impacts of absorbents, concentrations and flow rates of feeding gas and absorbent solution, cyclic loading of CO2 on the removal rate and the mass transfer velocity of CO2 are discussed. The results demonstrate that the mass transfer velocity was 7.1 mol x (m2 x s)(-1) for 1 mol x L(-1) MEA with flow rate of 0.1 m x s(-1) and flue gas with that of 0.211 m x s(-1). For 1 mol L(-1) AAAP with flow rate of 0.05 m x s(-1) and flue gas of 0.211 m x s(-1), CO2 removal rate (eta) was 93.2 % and eta was 98% for 4 mol x L(-1) AAAP under the same conditions. AAAP being absorbent, eta was higher than 90% in a wider range of concentrations of CO2. It indicates that membrane-based absorption process is a widely-applied and promising way of CO2 removal from flue gas of power plants, which not only appropriates for CO2 removal of flue gas of widely-used PF and NGCC, but also for that of flue gas of IGCC can be utilized widely in future.

  18. Phytosterol ester processing in the small intestine: impact on cholesterol availability for absorption and chylomicron cholesterol incorporation in healthy humans.

    PubMed

    Amiot, Marie Josèphe; Knol, Diny; Cardinault, Nicolas; Nowicki, Marion; Bott, Romain; Antona, Claudine; Borel, Patrick; Bernard, Jean-Paul; Duchateau, Guus; Lairon, Denis

    2011-06-01

    Phytosterols (plant sterols and stanols) can lower intestinal cholesterol absorption, but the complex dynamics of the lipid digestion process in the presence of phytosterol esters (PEs) are not fully understood. We performed a clinical experiment in intubated healthy subjects to study the time course of changes in the distribution of all lipid moieties present in duodenal phases during 4 h of digestion of meals with 3.2 g PE (PE meal) or without (control meal) PE. In vitro experiments under simulated gastrointestinal conditions were also performed. The addition of PE did not alter triglyceride (TG) hydrolysis in the duodenum or subsequent chylomicron TG occurrence in the circulation. In contrast, cholesterol accumulation in the duodenum aqueous phase was markedly reduced in the presence of PE (-32%, P < 0.10). In vitro experiments confirmed that PE reduces cholesterol transfer into the aqueous phase. The addition of PE resulted in a markedly reduced presence of meal-derived hepta-deuterated cholesterol in the circulation, i.e., in chylomicrons (-43%, PE meal vs. control; P < 0.0001) and plasma (-54%, PE meal vs. control; P < 0.0001). The present data show that addition of PE to a meal does not alter TG hydrolysis but displaces cholesterol from the intestinal aqueous phase and lowers chylomicron cholesterol occurrence in humans.

  19. Processes, dynamics and modelling of radiocaesium cycling in a chronosequence of Chernobyl-contaminated Scots pine (Pinus sylvestris L.) plantations.

    PubMed

    Goor, François; Thiry, Yves

    2004-06-05

    In a large forested area affected by the Chernobyl radioactive fallout, especially in CIS, the lasting recycling of radiocaesium (137Cs) by the trees is a source of long-term contamination of woody products. The quantitative description of the 137Cs dynamics in contaminated forest is a prerequisite to predictive modelling and further management of such territories. Three even-aged mono-specific Scots pine stands (17, 37 and 57 years old) were selected in a contaminated woodland in southeastern Belarus to constitute an adequate chronosequence. We determined the potassium and radiocaesium annual fluxes involved in the biological cycling in each stand using a well-documented calculation methodology. Qualitatively, 137Cs was shown to be rapidly recycled in trees through the same pathways as K and to redistribute similarly between the tree components. Compared to K, a higher fraction of 137Cs, corresponding to about the half of the annual uptake, is immobilised in perennial organs. With tree development, trunk wood and bark become prevailing sinks for 137Cs since they represent an increasing pool of biomass. In the pine chronosequence, the current root absorption, respectively, mobilizes 0.53, 0.32 and 0.31% year(-1) of the total 137Cs pool in soil. Variations in the 137Cs uptake do not reflect differences in the 137Cs balance between stands. In the two older stands, 51 and 71% of the current tree contamination are related to earlier accumulation subsequent to the initial fallout interception and recycling. The soil is the dominant source of long-term tree contamination. A simple modelling based on the measured 137Cs fluxes indicates that, for young stands, radioactive decay-corrected contamination would stabilize after reaching a maximum of 25 years after the 137Cs deposition. Stemwood presents a maximum of 15 years after the deposition and decrease afterwards mainly through radioactive decay. In the older stands, the decontamination is constant without local maximum

  20. Comparison of Overall Resource Consumption of Biosolids Management System Processes Using Exergetic Life Cycle Assessment.

    PubMed

    Alanya, Sevda; Dewulf, Jo; Duran, Metin

    2015-08-18

    This study focused on the evaluation of biosolids management systems (BMS) from a natural resource consumption point of view. Additionally, the environmental impact of the facilities was benchmarked using Life Cycle Assessment (LCA) to provide a comprehensive assessment. This is the first study to apply a Cumulative Exergy Extraction from the Natural Environment (CEENE) method for an in-depth resource use assessment of BMS where two full-scale BMS and seven system variations were analyzed. CEENE allows better system evaluation and understanding of how much benefit is achievable from the products generated by BMS, which have valorization potential. LCA results showed that environmental burden is mostly from the intense electricity consumption. The CEENE analysis further revealed that the environmental burden is due to the high consumption of fossil and nuclear-based natural resources. Using Cumulative Degree of Perfection, higher resource-use efficiency, 53%, was observed in the PTA-2 where alkaline stabilization rather than anaerobic digestion is employed. However, an anaerobic digestion process is favorable over alkaline stabilization, with 35% lower overall natural resource use. The most significant reduction of the resource footprint occurred when the output biogas was valorized in a combined heat and power system.

  1. Cycling excitation process: An ultra efficient and quiet signal amplification mechanism in semiconductor

    SciTech Connect

    Liu, Yu-Hsin; Yan, Lujiang; Zhang, Alex Ce; Hall, David; Niaz, Iftikhar Ahmad; Zhou, Yuchun; Sham, L. J.; Lo, Yu-Hwa

    2015-08-03

    Signal amplification, performed by transistor amplifiers with its merit rated by the efficiency and noise characteristics, is ubiquitous in all electronic systems. Because of transistor thermal noise, an intrinsic signal amplification mechanism, impact ionization was sought after to complement the limits of transistor amplifiers. However, due to the high operation voltage (30-200 V typically), low power efficiency, limited scalability, and, above all, rapidly increasing excess noise with amplification factor, impact ionization has been out of favor for most electronic systems except for a few applications such as avalanche photodetectors and single-photon Geiger detectors. Here, we report an internal signal amplification mechanism based on the principle of the phonon-assisted cycling excitation process (CEP). Si devices using this concept show ultrahigh gain, low operation voltage, CMOS compatibility, and, above all, quantum limit noise performance that is 30 times lower than devices using impact ionization. Established on a unique physical effect of attractive properties, CEP-based devices can potentially revolutionize the fields of semiconductor electronics.

  2. Increased nitrogen cycling facilitates native forest regeneration: potential for restoring extinct ecological processes?

    PubMed

    Tanentzap, Andrew J; Lee, William G; Monks, Adrian

    2013-01-01

    Ecological processes often maintain the plant communities with which they have a long evolutionary association, and so their loss may favor invasions by nonnative species. We simulated the effects of fecal deposition and soil turnover by the extinct avian megafauna of New Zealand to test their influence on woody plant regeneration and nonnative plant invasion in a cool temperate rain forest. Hen manure increased soil available NO3-, leading to greater seedling regeneration relative to control plots. Although soil P was elevated within plots treated with hen manure, concentrations also increased within plots treated with liquid fertilizer, which did not have different seedling densities relative to controls. Simulated avian soil disturbance did not increase seedling densities, and none of the three treatments affected the proportion of woody seedlings that were nonnative. However, pretreatment variation in NO3- availability, which reflected longer-term rates of nitrogen cycling, reduced community invasibility. Our findings suggest that avian-derived nitrogen inputs increase the regeneration of native forests, raising the question of whether the functional role of extinct megaherbivores is absent in New Zealand.

  3. [Intensity of the microbiological processes of the methane cycle in different types of Baltic lakes].

    PubMed

    Dziuban, A N

    2002-01-01

    The intensity of the microbiological processes of methane formation (MF) and methane oxidation (MO) was determined in the sediments and water of different types of Baltic lakes. The emission of methane from the lake sediments and methane distribution in the water column of the lakes were studied as functions of the lake productivity and hydrologic conditions. During summers, the intensity of MF in the lake sediments and waters varied from 0.001 to 106 ml CH4/(dm3 day) and from 0 to 3.2 ml CH4/(1 day), respectively, and the intensity of MO in the sediments and water varied from 0 to 11.2 ml CH4/(dm3 day) and from 0 to 1.1 ml CH4/(1 day), respectively. The total methane production (MP) in the lakes varied from 15 to 5000 ml CH4/(m2 day). In anoxic waters, the MP comprised 9-18% of the total PM in the lakes. The consumption of organic carbon for methanogenesis varied from 0.03 to 9.7 g/(m2 day). The role of the methane cycle in the degradation of organic matter in the lakes increased with their productivity.

  4. Bottom-up processes influence the demography and life-cycle phenology of Hawaiian bird communities.

    PubMed

    Wolfe, Jared D; Ralph, C John; Wiegardt, Andrew

    2017-08-05

    Changes in climate can indirectly regulate populations at higher trophic levels by influencing the availability of food resources in the lower reaches of the food web. As such, species that rely on fruit and nectar food resources may be particularly sensitive to these bottom-up perturbations due to the strength of their trophic linkages with climatically-influenced plants. To measure the influence of climatically-mediated, bottom-up processes, we used climate, bird capture, bird count, and plant phenology data from the Big Island of Hawaii to construct a series of structural equation and abundance models. Our results suggest that fruit and nectar-eating birds arrange life cycle events around climatically-influenced food resources, while some of these same food resources also influence seasonal patterns of abundance. This trend was particularly strong for two native nectarivores, 'I'iwi and 'Apapane, where we found that the dissimilar timing of molting and breeding activity was associated with peak abundance of the two most common flowers at our study site which, in turn, were each driven by dissimilar climatic cues. Given the rapidly changing Hawaiian climate, we suggest that determining behavioral plasticity, or evolutionary capacity of birds to mitigate changes in climatically-influenced food resources, should be recognized as a future research priority. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  5. A Mechanistic Treatment of the Dominant Soil Nitrogen Cycling Processes: Model Development, Testing, and Application

    SciTech Connect

    Riley, William; Maggi, F.; Gu, C.; Riley, W.J.; Hornberger, G.M.; Venterea, R.T.; Xu, T.; Spycher, N.; Steefel, C.; Miller, N.L.; Oldenburg, C.M.

    2008-05-01

    The development and initial application of a mechanistic model (TOUGHREACT-N) designed to characterize soil nitrogen (N) cycling and losses are described. The model couples advective and diffusive nutrient transport, multiple microbial biomass dynamics, and equilibrium and kinetic chemical reactions. TOUGHREACT-N was calibrated and tested against field measurements to assess pathways of N loss as either gas emission or solute leachate following fertilization and irrigation in a Central Valley, California, agricultural field as functions of fertilizer application rate and depth, and irrigation water volume. Our results, relative to the period before plants emerge, show that an increase in fertilizer rate produced a nonlinear response in terms of N losses. An increase of irrigation volume produced NO{sub 2}{sup -} and NO{sub 3}{sup -} leaching, whereas an increase in fertilization depth mainly increased leaching of all N solutes. In addition, nitrifying bacteria largely increased in mass with increasing fertilizer rate. Increases in water application caused nitrifiers and denitrifiers to decrease and increase their mass, respectively, while nitrifiers and denitrifiers reversed their spatial stratification when fertilizer was applied below 15 cm depth. Coupling aqueous advection and diffusion, and gaseous diffusion with biological processes, closely captured actual conditions and, in the system explored here, significantly clarified interpretation of field measurements.

  6. Transition from intelligence cycle to intelligence process: the network-centric intelligence in narrow seas

    NASA Astrophysics Data System (ADS)

    Büker, Engin

    2015-05-01

    The defence technologies which have been developing and changing rapidly, today make it difficult to be able to foresee the next environment and spectrum of warfare. When said change and development is looked in specific to the naval operations, it can be said that the possible battlefield and scenarios to be developed in the near and middle terms (5-20 years) are more clarified with compare to other force components. Network Centric Naval Warfare Concept that was developed for the floating, diving and flying fleet platforms which serves away from its own mainland for miles, will keep its significance in the future. Accordingly, Network Centric Intelligence structure completely integrating with the command and control systems will have relatively more importance. This study will firstly try to figure out the transition from the traditional intelligence cycle that is still used in conventional war to Network Centric Intelligence Production Process. In the last part, the use of this new approach on the base of UAV that is alternative to satellite based command control and data transfer systems in the joint operations in narrow seas will be examined, a model suggestion for the use of operative and strategic UAVs which are assured within the scope of the NATO AGS2 for this aim will be brought.

  7. Solar cycles or random processes? Evaluating solar variability in Holocene climate records.

    PubMed

    Turner, T Edward; Swindles, Graeme T; Charman, Dan J; Langdon, Peter G; Morris, Paul J; Booth, Robert K; Parry, Lauren E; Nichols, Jonathan E

    2016-04-05

    Many studies have reported evidence for solar-forcing of Holocene climate change across a range of archives. These studies have compared proxy-climate data with records of solar variability (e.g. (14)C or (10)Be), or have used time series analysis to test for the presence of solar-type cycles. This has led to some climate sceptics misrepresenting this literature to argue strongly that solar variability drove the rapid global temperature increase of the twentieth century. As proxy records underpin our understanding of the long-term processes governing climate, they need to be evaluated thoroughly. The peatland archive has become a prominent line of evidence for solar forcing of climate. Here we examine high-resolution peatland proxy climate data to determine whether solar signals are present. We find a wide range of significant periodicities similar to those in records of solar variability: periods between 40-100 years, and 120-140 years are particularly common. However, periodicities similar to those in the data are commonly found in random-walk simulations. Our results demonstrate that solar-type signals can be the product of random variations alone, and that a more critical approach is required for their robust interpretation.

  8. Solar cycles or random processes? Evaluating solar variability in Holocene climate records

    PubMed Central

    Turner, T. Edward; Swindles, Graeme T.; Charman, Dan J.; Langdon, Peter G.; Morris, Paul J.; Booth, Robert K.; Parry, Lauren E.; Nichols, Jonathan E.

    2016-01-01

    Many studies have reported evidence for solar-forcing of Holocene climate change across a range of archives. These studies have compared proxy-climate data with records of solar variability (e.g. 14C or 10Be), or have used time series analysis to test for the presence of solar-type cycles. This has led to some climate sceptics misrepresenting this literature to argue strongly that solar variability drove the rapid global temperature increase of the twentieth century. As proxy records underpin our understanding of the long-term processes governing climate, they need to be evaluated thoroughly. The peatland archive has become a prominent line of evidence for solar forcing of climate. Here we examine high-resolution peatland proxy climate data to determine whether solar signals are present. We find a wide range of significant periodicities similar to those in records of solar variability: periods between 40–100 years, and 120–140 years are particularly common. However, periodicities similar to those in the data are commonly found in random-walk simulations. Our results demonstrate that solar-type signals can be the product of random variations alone, and that a more critical approach is required for their robust interpretation. PMID:27045989

  9. Nitrogen cycling in Bioregenerative Life Support Systems: Challenges for waste refinery and food production processes

    NASA Astrophysics Data System (ADS)

    Clauwaert, Peter; Muys, Maarten; Alloul, Abbas; De Paepe, Jolien; Luther, Amanda; Sun, Xiaoyan; Ilgrande, Chiara; Christiaens, Marlies E. R.; Hu, Xiaona; Zhang, Dongdong; Lindeboom, Ralph E. F.; Sas, Benedikt; Rabaey, Korneel; Boon, Nico; Ronsse, Frederik; Geelen, Danny; Vlaeminck, Siegfried E.

    2017-05-01

    In order to sustain human life in an isolated environment, an efficient conversion of wasted nutrients to food might become mandatory. This is particularly the case for space missions where resupply from earth or in-situ resource utilization is not possible or desirable. A combination of different technologies is needed to allow full recycling of e.g. nitrogenous compounds in space. In this review, an overview is given of the different essential processes and technologies that enable closure of the nitrogen cycle in Bioregenerative Life Support Systems (BLSS). Firstly, a set of biological and physicochemical refinery stages ensures efficient conversion of waste products into the building blocks, followed by the production of food with a range of biological methods. For each technology, bottlenecks are identified. Furthermore, challenges and outlooks are presented at the integrated system level. Space adaptation and integration deserve key attention to enable the recovery of nitrogen for the production of nutritional food in space, but also in closed loop systems on earth.

  10. Trickling filter for urea and bio-waste processing - dynamic modelling of nitrogen cycle

    NASA Astrophysics Data System (ADS)

    Zhukov, Anton; Hauslage, Jens; Tertilt, Gerin; Bornemann, Gerhild

    Mankind’s exploration of the solar system requires reliable Life Support Systems (LSS) enabling long duration manned space missions. In the absence of frequent resupply missions, closure of the LSS will play a very important role and its maximisation will to a large extent drive the selection of appropriate LSS architectures. One of the significant issues on the way to full closure is to effectively utilise biological wastes such as urine, inedible biomass etc. A very promising concept of biological waste reprocessing is the use of trickling filters which are currently being developed and investigated by DLR, Cologne, Germany. The concept is called Combined Regenerative Organic-Food Production (C.R.O.P.) and is based on the microbiological treatment of biological wastes and reprocessing them into aqueous fertilizer which can directly be used in a greenhouse for food production. Numerous experiments have been and are being conducted by DLR in order to fully understand and characterize the process. The human space exploration group of the Technical University of Munich (TUM) in cooperation with DLR has started to establish a dynamic model of the trickling filter system to be able to assess its performance on the LSS level. In the first development stage the model covers the nitrogen cycle enabling to simulate urine processing. This paper describes briefly the C.R.O.P. concept and the status of the trickling filter model development. The model is based on enzyme-catalyzed reaction kinetics for the fundamental microbiological reaction chain and is created in MATLAB. Verification and correlation of the developed model with experiment results has been performed. Several predictive studies for batch sequencing behavior have been performed, demonstrating a good capability of C.R.O.P. concept to be used in closed LSS. Achieved results are critically discussed and way forward is presented.

  11. [Microbial processes of the carbon and sulfur cycles in the White Sea].

    PubMed

    Savvichev, A S; Rusanov, I I; Zakharova, E E; Veslopolova, E F; Mitskevich, I N; Kravchishina, M D; Lein, A Iu; Ivanov, M V

    2008-01-01

    The present paper contains the results of our microbiological and biogeochemical investigations carried out during a series of expeditions to the White Sea in 2002-2006. The studies were conducted in the open part of the White Sea, as well as in the Onega, Dvina, and Kandalaksha bays. In August 2006, the photosynthetic productivity in the surface water layer was low (47-145 mg C m(-2) day(-1)). Quantitative characteristics of microbial numbers and activity of the the key microbial processes occurring in the water column of the White Sea were explored. Over the 5-year period of observations, the total number of bacterial cells in the surface layer of the water column varied from 50 to 600 thousand cells ml(-1). In August 2006, bacterioplankton production (BP) was estimated to be 0.26-3.3 microg C l(-1) day(-1); the P/B coefficient varied from 0.22 to 0.93. The suspended organic matter had a lighter isotope composition (from -28.0 to -30.5 per thousand) due to the predominance of terrigenous organic matter delivered by the Northern Dvina waters. The interseasonal and interannual variation coefficients for phytoplankton production and BP numbers are compared. The bacterioplankton community of the White Sea's deep water was found to be more stable than that of the surface layer. In the surface layer of bottom sediments, methane concentration was 0.2-5.2 microl dm(-3); the rate of bacterial sulfate reduction was 18-260 microg S dm(-3) day(-1); and the rates of methane production and oxidation were 24-123 and 6-13 nl CH4 dm(-3) day(-1) respectively. We demonstrated that the rates of microbial processes of the carbon and sulfur cycles occurring in the sediments of the White Sea basin were low.

  12. Convective Cloud and Rainfall Processes Over the Maritime Continent: Simulation and Analysis of the Diurnal Cycle

    NASA Astrophysics Data System (ADS)

    Gianotti, Rebecca L.

    The Maritime Continent experiences strong moist convection, which produces significant rainfall and drives large fluxes of heat and moisture to the upper troposphere. Despite the importance of these processes to global circulations, current predictions of climate change over this region are still highly uncertain, largely due to inadequate representation of the diurnally-varying processes related to convection. In this work, a coupled numerical model of the land-atmosphere system (RegCM3-IBIS) is used to investigate how more physically-realistic representations of these processes can be incorporated into large-scale climate models. In particular, this work improves simulations of convective-radiative feedbacks and the role of cumulus clouds in mediating the diurnal cycle of rainfall. Three key contributions are made to the development of RegCM3-IBIS. Two pieces of work relate directly to the formation and dissipation of convective clouds: a new representation of convective cloud cover, and a new parameterization of convective rainfall production. These formulations only contain parameters that can be directly quantified from observational data, are independent of model user choices such as domain size or resolution, and explicitly account for subgrid variability in cloud water content and nonlinearities in rainfall production. The third key piece of work introduces a new method for representation of cloud formation within the boundary layer. A comprehensive evaluation of the improved model was undertaken using a range of satellite-derived and ground-based datasets, including a new dataset from Singapore's Changi airport that documents diurnal variation of the local boundary layer height. The performance of RegCM3-IBIS with the new formulations is greatly improved across all evaluation metrics, including cloud cover, cloud liquid water, radiative fluxes and rainfall, indicating consistent improvement in physical realism throughout the simulation. This work

  13. Solvent effects on the excited-state processes of protochlorophyllide: a femtosecond time-resolved absorption study.

    PubMed

    Dietzek, B; Kiefer, W; Hermann, G; Popp, J; Schmitt, M

    2006-03-09

    The excited-state dynamics of protochlorophyllide a, a porphyrin-like compound and, as substrate of the NADPH/protochlorophyllide oxidoreductase, a precursor of chlorophyll biosynthesis, is studied by femtosecond absorption spectroscopy in a variety of solvents, which were chosen to mimic different environmental conditions in the oxidoreductase complex. In the polar solvents methanol and acetonitrile, the excited-state dynamics differs significantly from that in the nonpolar solvent cyclohexane. In methanol and acetonitrile, the relaxation dynamics is multiexponential with three distinguishable time scales of 4.0-4.5 ps for vibrational relaxation and vibrational energy redistribution of the initially excited S1 state, 22-27 ps for the formation of an intermediate state, most likely with a charge transfer character, and 200 ps for the decay of this intermediate state back to the ground state. In the nonpolar solvent cyclohexane, only the 4.5 ps relaxational process can be observed, whereas the intermediate intramolecular charge transfer state is not populated any longer. In addition to polarity, solvent viscosity also affects the excited-state processes. Upon increasing the viscosity by adding up to 60% glycerol to a methanolic solution, a deceleration of the 4 and 22 ps decay rates from the values in pure methanol is found. Apparently not only vibrational cooling of the S1 excited state is slowed in the more viscous surrounding, but the formation rate of the intramolecular charge transfer state is also reduced, suggesting that nuclear motions along a reaction coordinate are involved in the charge transfer. The results of the present study further specify the model of the excited-state dynamics in protochlorophyllide a as recently suggested (Chem. Phys. Lett. 2004, 397, 110).

  14. Processes Controlling the Seasonal Cycle of Arctic Aerosol Number and Size Distributions

    NASA Astrophysics Data System (ADS)

    Wentworth, G.; Croft, B.; Martin, R.; Leaitch, W. R.; Tunved, P.; Breider, T. J.; D'Andrea, S.; Pierce, J. R.; Murphy, J. G.; Kodros, J.; Abbatt, J.

    2015-12-01

    Measurements at high-Arctic sites show a strong seasonal cycle in aerosol number and size. The number of aerosols with diameters larger than 20 nm exhibits a maximum in late spring associated with a dominant accumulation mode, and a second maximum in the summer associated with a dominant Aitken mode. Seasonal-mean aerosol effective diameter ranges from about 160 nm in summer to 250 nm in winter. This study interprets these seasonal cycles with the GEOS-Chem-TOMAS global aerosol microphysics model. We find improved agreement with in situ measurements (SMPS) of aerosol size at both Alert, Nunavut, and Mt. Zeppelin, Svalbard following model developments: 1) increase the efficiency of wet scavenging in the Arctic summer and 2) represent coagulation between interstitial aerosols and aerosols activated to form cloud droplets. Our simulations indicate that the dominant summer-time Aitken mode is associated with increased efficiency of wet removal, which limits the number of larger aerosols and promotes local new-aerosol formation. We also find an important role of interstitial coagulation in clouds in the Arctic, which limits the number of Aitken-mode aerosols in the non-summer seasons when direct wet removal of these aerosols is inefficient. The summertime Arctic atmosphere is particularly pristine and strongly influenced by natural regional emissions which have poorly understood climate impacts. Especially influenced are the climatic roles of atmospheric particles and clouds. Here we present evidence that ammonia (NH3) emissions from migratory-seabird guano (dung) are the primary contributor to summertime free ammonia levels recently measured in the Canadian Arctic atmosphere. These findings suggest that ammonia from seabird guano is a key factor contributing to bursts of new-particle formation, which are observed every summer in the near-surface atmosphere at Alert, Canada. Chemical transport model simulations show that these newly formed particles can grow by vapour

  15. Cell output, cell cycle duration and neuronal specification: a model of integrated mechanisms of the neocortical proliferative process

    NASA Technical Reports Server (NTRS)

    Caviness, V. S. Jr; Goto, T.; Tarui, T.; Takahashi, T.; Bhide, P. G.; Nowakowski, R. S.

    2003-01-01

    The neurons of the neocortex are generated over a 6 day neuronogenetic interval that comprises 11 cell cycles. During these 11 cell cycles, the length of cell cycle increases and the proportion of cells that exits (Q) versus re-enters (P) the cell cycle changes systematically. At the same time, the fate of the neurons produced at each of the 11 cell cycles appears to be specified at least in terms of their laminar destination. As a first step towards determining the causal interrelationships of the proliferative process with the process of laminar specification, we present a two-pronged approach. This consists of (i) a mathematical model that integrates the output of the proliferative process with the laminar fate of the output and predicts the effects of induced changes in Q and P during the neuronogenetic interval on the developing and mature cortex and (ii) an experimental system that allows the manipulation of Q and P in vivo. Here we show that the predictions of the model and the results of the experiments agree. The results indicate that events affecting the output of the proliferative population affect both the number of neurons produced and their specification with regard to their laminar fate.

  16. Cell output, cell cycle duration and neuronal specification: a model of integrated mechanisms of the neocortical proliferative process

    NASA Technical Reports Server (NTRS)

    Caviness, V. S. Jr; Goto, T.; Tarui, T.; Takahashi, T.; Bhide, P. G.; Nowakowski, R. S.

    2003-01-01

    The neurons of the neocortex are generated over a 6 day neuronogenetic interval that comprises 11 cell cycles. During these 11 cell cycles, the length of cell cycle increases and the proportion of cells that exits (Q) versus re-enters (P) the cell cycle changes systematically. At the same time, the fate of the neurons produced at each of the 11 cell cycles appears to be specified at least in terms of their laminar destination. As a first step towards determining the causal interrelationships of the proliferative process with the process of laminar specification, we present a two-pronged approach. This consists of (i) a mathematical model that integrates the output of the proliferative process with the laminar fate of the output and predicts the effects of induced changes in Q and P during the neuronogenetic interval on the developing and mature cortex and (ii) an experimental system that allows the manipulation of Q and P in vivo. Here we show that the predictions of the model and the results of the experiments agree. The results indicate that events affecting the output of the proliferative population affect both the number of neurons produced and their specification with regard to their laminar fate.

  17. Renovation of CPF (Chemical Processing Facility) for Development of Advanced Fast Reactor Fuel Cycle System

    SciTech Connect

    Shinichi Aose; Takafumi Kitajima; Kouji Ogasawara; Kazunori Nomura; Shigehiko Miyachi; Yoshiaki Ichige; Tadahiro Shinozaki; Shinichi Ohuchi

    2008-01-15

    CPF (Chemical Processing Facility) was constructed at Nuclear Fuel Cycle Engineering Laboratories of JAEA (Japan Atomic Energy Agency) in 1980 as a basic research field where spent fuel pins from fast reactor (FR) and high level liquid waste can be dealt with. The renovation consists of remodeling of the CA-3 cell and the laboratory A, installation of globe boxes, hoods and analytical equipments to the laboratory C and the analytical laboratory. Also maintenance equipments in the CA-5 cell which had been out of order were repaired. The CA-3 cell is the main cell in which important equipments such as a dissolver, a clarifier and extractors are installed for carrying out the hot test using the irradiated FR fuel. Since the CPF had specialized originally in the research function for the Purex process, it was desired to execute the research and development of such new, various reprocessing processes. Formerly, equipments were arranged in wide space and connected with not only each other but also with utility supply system mainly by fixed stainless steel pipes. It caused shortage of operation space in flexibility for basic experimental study. Old equipments in the CA-3 cell including vessels and pipes were removed after successful decontamination, and new equipments were installed conformably to the new design. For the purpose of easy installation and rearranging the experimental equipments, equipments are basically connected by flexible pipes. Since dissolver is able to be easily replaced, various dissolution experiments is conducted. Insoluble residue generated by dissolution of spent fuel is clarified by centrifugal. This small apparatus is effective to space-saving. Mini mixer settlers or centrifugal contactors are put on to the prescribed limited space in front of the backside wall. Fresh reagents such as solvent, scrubbing and stripping solution are continuously fed from the laboratory A to the extractor by the reagent supply system with semi-automatic observation

  18. Nebular UV Absorption Lines in Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Dinerstein, Harriet

    We propose to continue our Cycle 1 program of studying the Lyman and Werner bands of H_2, seen in absorption against the UV continua of planetary nebula central stars, which arise within neutral-molecular envelopes surrounding the ionized gas. These are the pump lines for a fluorescent cascade of near-infrared emission lines which are observed in many planetary nebulae. By observing the UV lines we can probe the chemical and thermal structure of the envelopes, as well as measure molecular column densities and clarify the excitation processes for the infrared lines. In Cycle 1 we were granted time for three targets, one of which was successfully observed shortly before submission of this proposal. Although the data were not yet available for examination, similar target observed by the project team revealed a rich set of H_2 circumstellar absorption features, demonstrating the feasibility of our program. FUSE spectra also include absorption features from atomic species such as O I and C II, which give rise to important far-infrared fine-structure cooling lines that likewise have been observed from planetary nebulae. In Cycle 2, we add as a secondary goal a search for nebular components of the O VI 032, 1038 AA absorption lines, which trace the presence of hot shocked gas, in nebulae with anomalously strong optical recombination lines of ions of oxygen and nitrogen. This will test a plausible hypothesis for the origin of this anomaly.

  19. Effects of gastric pH on oral drug absorption: In vitro assessment using a dissolution/permeation system reflecting the gastric dissolution process.

    PubMed

    Kataoka, Makoto; Fukahori, Miho; Ikemura, Atsumi; Kubota, Ayaka; Higashino, Haruki; Sakuma, Shinji; Yamashita, Shinji

    2016-04-01

    The aim of the present study was to evaluate the effects of gastric pH on the oral absorption of poorly water-soluble drugs using an in vitro system. A dissolution/permeation system (D/P system) equipped with a Caco-2 cell monolayer was used as the in vitro system to evaluate oral drug absorption, while a small vessel filled with simulated gastric fluid (SGF) was used to reflect the gastric dissolution phase. After applying drugs in their solid forms to SGF, SGF solution containing a 1/100 clinical dose of each drug was mixed with the apical solution of the D/P system, which was changed to fasted state-simulated intestinal fluid. Dissolved and permeated amounts on applied amount of drugs were then monitored for 2h. Similar experiments were performed using the same drugs, but without the gastric phase. Oral absorption with or without the gastric phase was predicted in humans based on the amount of the drug that permeated in the D/P system, assuming that the system without the gastric phase reflected human absorption with an elevated gastric pH. The dissolved amounts of basic drugs with poor water solubility, namely albendazole, dipyridamole, and ketoconazole, in the apical solution and their permeation across a Caco-2 cell monolayer were significantly enhanced when the gastric dissolution process was reflected due to the physicochemical properties of basic drugs. These amounts resulted in the prediction of higher oral absorption with normal gastric pH than with high gastric pH. On the other hand, when diclofenac sodium, the salt form of an acidic drug, was applied to the D/P system with the gastric phase, its dissolved and permeated amounts were significantly lower than those without the gastric phase. However, the oral absorption of diclofenac was predicted to be complete (96-98%) irrespective of gastric pH because the permeated amounts of diclofenac under both conditions were sufficiently high to achieve complete absorption. These estimations of the effects of

  20. The development of a new technical platform to measure soil organic nitrogen cycling processes by microbes

    NASA Astrophysics Data System (ADS)

    Hu, Yuntao; Richter, Andreas; Wanek, Wolfgang

    2016-04-01

    Soil organic matter (SOM) decomposition is one of the most important processes of the global nitrogen cycle, having strong implications on soil N availability, terrestrial carbon cycling and soil carbon sequestration. During SOM decomposition low-molecular weight organic nitrogen (LMWON) is released which can be taken up by microbes (and plants). The breakdown of high-molecular weight organic nitrogen (HMWON, e.g. proteins, peptidoglycan, chitin, nucleic acids) represents the bottleneck of soil HMWON decomposition and is performed by extracellular enzymes released mainly by soil microorganisms. Despite that, the current understanding of the controls of these processes is incomplete. The only way to measure gross decomposition rates of these polymers is to use isotope pool dilution (IPD) techniques. In IPD approaches the product pool is isotopically enriched (by e.g. 15N) and the isotope dilution of this pool is measured over time. We have pioneered an IPD for protein and cellulose depolymerization, but IPD approaches for other polymers, specifically for important microbial necromass components such as chitin (fungi) and peptidoglycan (bacteria), or nucleic acids have not yet been developed. Here we present a workflow based on a universally applicable technical platform that allows to estimate the gross depolymerization rate of SOM (HMWON) at the molecular level, using ultra high performance liquid chromatography/high resolution Orbitrap mass spectrometry (UPLC/HRMS) combined with IPD techniques. The necessary isotopically labeled organic polymers (chitin, peptidoglycan and others) are extracted from laboratory bacterial and fungal cultures grown in fully isotopically labeled nutrient media (15N, 13C or both). A purification scheme for the different polymers is currently established. Labeled potential decomposition products (e.g. amino sugars and muropeptides from peptidoglycan, amino sugars and chitooligosaccharides from chitin, nucleotides and nucleosides from

  1. How does complex terrain influence responses of carbon and water cycle processes to climate variability and climate change?

    EPA Science Inventory

    We are pursuing the ambitious goal of understanding how complex terrain influences the responses of carbon and water cycle processes to climate variability and climate change. Our studies take place in H.J. Andrews Experimental Forest, an LTER (Long Term Ecological Research) site...

  2. How does complex terrain influence responses of carbon and water cycle processes to climate variability and climate change?

    EPA Science Inventory

    We are pursuing the ambitious goal of understanding how complex terrain influences the responses of carbon and water cycle processes to climate variability and climate change. Our studies take place in H.J. Andrews Experimental Forest, an LTER (Long Term Ecological Research) site...

  3. 77 FR 50724 - Developing Software Life Cycle Processes for Digital Computer Software Used in Safety Systems of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ... nuclear power plants described in the Institute of Electrical and Electronic Engineers (IEEE) Standard 1074-2006, ``IEEE Standard for Developing a Software Project Life Cycle Process,'' issued 2006. DATES... 1997. This RG endorses IEEE Std. 1074-2006, ``IEEE Standard for Developing a Software Project...

  4. Life cycle assessment of a coupled solar photocatalytic-biological process for wastewater treatment.

    PubMed

    Muñoz, Ivan; Peral, José; Ayllón, José Antonio; Malato, Sixto; Passarinho, Paula; Domènech, Xavier

    2006-11-01

    A comparative life cycle assessment (LCA) of two solar-driven advanced oxidation processes, namely heterogeneous semiconductor photocatalysis and homogeneous photo-Fenton, both coupled to biological treatment, is carried out in order to identify the environmentally preferable alternative to treat industrial wastewaters containing non-biodegradable priority hazardous substances. The study is based on solar pilot plant tests using alpha-methyl-phenylglycine as a target substance. The LCA study is based on the experimental results obtained, along with data from an industrial-scale plant. The system under study includes production of the plant infrastructure, chemicals, electricity, transport of all these materials to the plant site, management of the spent catalyst by transport and landfilling, as well as treatment of the biodegradable effluent obtained in a conventional municipal wastewater treatment plant, and excess sludge treatment by incineration. Nine environmental impact categories are included in the LCA: global warming, ozone depletion, human toxicity, freshwater aquatic toxicity, photochemical ozone formation, acidification, eutrophication, energy consumption, and land use. The experimental results obtained in the pilot plant show that solar photo-Fenton is able to obtain a biodegradable effluent much faster than solar heterogeneous photocatalysis, implying that the latter would require a much larger solar collector area in an industrial application. The results of the LCA show that, an industrial wastewater treatment plant based on heterogeneous photocatalysis involves a higher environmental impact than the photo-Fenton alternative, which displays impact scores 80-90% lower in most impact categories assessed. These results are mainly due to the larger size of the solar collector field needed by the plant.

  5. The influence of a neotropical herbivore (Lamponius portoricensis) on nutrient cycling and soil processes.

    PubMed

    Fonte, S J; Schowalter, T D

    2005-12-01

    The role of phytophagous insects in ecosystem nutrient cycling remains poorly understood. By altering the flow of litterfall nutrients from the canopy to the forest floor, herbivores may influence key ecosystem processes. We manipulated levels of herbivory in a lower montane tropical rainforest of Puerto Rico using the common herbivore, Lamponius portoricensis (Phasmatidea), on a prevalent understory plant, Piper glabrescens (Piperaceae), and measured the effects on nutrient input to the forest floor and on rates of litter decomposition. Four treatment levels of herbivory generated a full range of leaf area removal, from plants experiencing no herbivory to plants that were completely defoliated (>4,000 cm(2) leaf area removed during the 76-day study duration). A significant (P<0.05) positive regression was found between all measures of herbivory (total leaf area removed, greenfall production, and frass-related inputs) and the concentration of NO (3) (-) in ion exchange resin bags located in the litter layer. No significant relationship was found between any of the herbivory components and resin bag concentrations of NH (4) (+) or PO (4) (-) . Rates of litter decay were significantly affected by frass-related herbivore inputs. A marginally significant negative relationship was also found between the litter mass remaining at 47 days and total leaf area removed. This study demonstrated a modest, but direct relationship between herbivory and both litter decomposition and NO (3) (-) transfer to the forest floor. These results suggest that insect herbivores can influence forest floor nutrient dynamics and thus merit further consideration in discussions on ecosystem nutrient dynamics.

  6. The environmental footprint of a membrane bioreactor treatment process through Life Cycle Analysis.

    PubMed

    Ioannou-Ttofa, L; Foteinis, S; Chatzisymeon, E; Fatta-Kassinos, D

    2016-10-15

    This study includes an environmental analysis of a membrane bioreactor (MBR), the objective being to quantitatively define the inventory of the resources consumed and estimate the emissions produced during its construction, operation and end-of-life deconstruction. The environmental analysis was done by the life cycle assessment (LCA) methodology, in order to establish with a broad perspective and in a rigorous and objective way the environmental footprint and the main environmental hotspots of the examined technology. Raw materials, equipment, transportation, energy use, as well as air- and waterborne emissions were quantified using as a functional unit, 1m(3) of urban wastewater. SimaPro 8.0.3.14 was used as the LCA analysis tool, and two impact assessment methods, i.e. IPCC 2013 version 1.00 and ReCiPe version 1.10, were employed. The main environmental hotspots of the MBR pilot unit were identified to be the following: (i) the energy demand, which is by far the most crucial parameter that affects the sustainability of the whole process, and (ii) the material of the membrane units. Overall, the MBR technology was found to be a sustainable solution for urban wastewater treatment, with the construction phase having a minimal environmental impact, compared to the operational phase. Moreover, several alternative scenarios and areas of potential improvement, such as the diversification of the electricity mix and the material of the membrane units, were examined, in order to minimize as much as possible the overall environmental footprint of this MBR system. It was shown that the energy mix can significantly affect the overall sustainability of the MBR pilot unit (i.e. up to 95% reduction of the total greenhouse gas emissions was achieved with the use of an environmentally friendly energy mix), and the contribution of the construction and operational phase to the overall environmental footprint of the system.

  7. Implementation An image processing technique for video motion analysis during the gait cycle canine

    NASA Astrophysics Data System (ADS)

    López, G.; Hernández, J. O.

    2017-01-01

    Nowadays the analyses of human movement, more specifically of the gait have ceased to be a priority for our species. Technological advances and implementations engineering have joined to obtain data and information regarding the gait cycle in another animal species. The aim of this paper is to analyze the canine gait in order to get results that describe the behavior of the limbs during the gait cycle. The research was performed by: 1. Dog training, where it is developed the step of adaptation and trust; 2. Filming gait cycle; 3. Data acquisition, in order to obtain values that describe the motion cycle canine and 4. Results, obtaining the kinematics variables involved in the march. Which are essential to determine the behavior of the limbs, as well as for the development of prosthetic or orthotic. This project was carried out with conventional equipment and using computational tools easily accessible.

  8. ENVIRONMENTAL COMPARISON METRICS FOR LIFE CYCLE IMPACT ASSESSMENT AND PROCESS DESIGN

    EPA Science Inventory

    Metrics (potentials, potency factors, equivalency factors or characterization factors) are available to support the environmental comparison of alternatives in application domains like proces design and product life-cycle assessment (LCA). These metrics typically provide relative...

  9. ENVIRONMENTAL COMPARISON METRICS FOR LIFE CYCLE IMPACT ASSESSMENT AND PROCESS DESIGN

    EPA Science Inventory

    Metrics (potentials, potency factors, equivalency factors or characterization factors) are available to support the environmental comparison of alternatives in application domains like proces design and product life-cycle assessment (LCA). These metrics typically provide relative...

  10. Effect of reprocessing cycles on the degradation of polypropylene copolymer filled with talc or montmorillonite during injection molding process

    SciTech Connect

    Demori, R.; Mauler, R. S.; Ashton, E.; Weschenfelder, V. F.; Cândido, L. H. A.; Kindlein, W.

    2015-05-22

    Mechanical recycling of polymeric materials is a favorable technique resulting in economic and environmental benefits, especially in the case of polymers with a high production volume as the polypropylene copolymer (PP). However, recycling by reprocessing techniques can lead to thermal, mechanical or thermo-oxidative degradation that can affect the structure of the polymer and subsequently the material properties. PP filled with montmorillonite (MMT) or talc are widely produced and studied, however, its degradation reactions by reprocessing cycles are poorly studied so far. In this study, the effects of reprocessing cycles in the structure and in the properties of the PP/MMT and PP/Talc were evaluated. The samples were mixed with 5% talc or MMT Cloisite C15A in a twin-screw extrusion. After extrusion, this filled material was submitted to five reprocessing cycles through an injection molding process. In order to evaluate the changes induced by reprocessing techniques, the samples were characterized by DSC, FT-IR, Izod impact and tensile strength tests. The study showed that Young modulus, elongation at brake and Izod impact were not affected by reprocessing cycles, except when using talc. In this case, the elongation at brake reduced until the fourth cycle, showing rigidity increase. The DSC results showed that melting and crystallization temperature were not affected. A comparison of FT-IR spectra of the reprocessed indicated that in both samples, between the first and the fifth cycle, no noticeable change has occurred. Thus, there is no evidence of thermo oxidative degradation. In general, these results suggest that PP reprocessing cycles using MMT or talc does not change the material properties until the fifth cycle.

  11. Automated Data Collection and Processing for a Concentric/Eccentric Cycle Ergometer,

    DTIC Science & Technology

    1986-02-01

    A/D converter samples from the 7 cycle transducers. The list values are not in meaningful units of force or angle but in " machine units", values from...The calibration factors are used to convert machine unit values to newtons and radians. There are 100 rows of transducer data in a file for each cycle...smoothing is required. Calibration factors are used to convert machine units corresponding to normal and frictional forces from each pedal into newtons

  12. 10-MW demonstration of the gas suspension absorption process at TVA`s Center for Emissions Research. Final report

    SciTech Connect

    1995-03-01

    The Tennessee Valley Authority (TVA) in cooperation with AirPol Inc., and the U.S. Department of Energy (DOE), has recently completed a successful 17-month test program with the AirPol Gas Suspension Absorption (GSA) flue gas desulfurization (FGD) process at TVA`s Center for Emissions Research (CER). This project was selected by DOE for funding in the third round of the Clean Coal Technology Program. This 10-MW demonstration of the GSA FGD system at the CER was the first application of this technology in the U.S. The GSA test program, which was cofunded two-thirds by TVA and one-third by DOE/AirPol, was completed over a 17-month period from November 1, 1992 to March 31, 1993. This test program demonstrated that the GSA FGD technology could achieve high SO{sub 2} removal efficiencies (90+ percent) for a 2.7 percent sulfur (as-fired) coal application, while maintaining particulate emissions below the New Source Performance Standards (NSPS), i.e., 0.03 lb/MBtu, in a four-field electrostatic precipitator. The reliability and operability of this system was also demonstrated in a 28-day, 24 hour/day, continuous run during which the GSA unit simultaneously achieved high SO{sub 2} removal efficiencies (90+ percent) and maintained particulate emissions below the NSPS. Also, the air toxics removal capabilities of the GSA system were determined in a series of tests. A 1-MW pulsejet baghouse (PJBH) pilot plant was also tested in conjunction with this GSA test program. This PJBH testing was initially cofunded by TVA and the Electric Power Research Institute, who were later joined by AirPol and DOE in sponsoring this PJBH testing. A 14-day PJBH demonstration run was also completed to confirm the reliability of this system.

  13. Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

    USGS Publications Warehouse

    Repert, Deborah A.; Underwood, Jennifer C.; Smith, Richard L.; Song, Bongkeun

    2014-01-01

    Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sediment samples collected over distinct water cycle seasons. In conjunction, the microbial community composition in the bed sediments using genes involved in N-cycling (narG, napA, nosZ, and amoA) and 16S rRNA gene pyrosequences was examined. Temporal variation was observed in net N mineralization, nitrate uptake, and denitrification rate potentials and correlated strongly with sediment carbon (C) and extractable N content and microbial community composition rather than with river water nutrient concentrations. The C content of the bed sediment was notably impacted by the spring flood, ranging from 1.1% in the midst of an ice-jam to 0.1% immediately after ice-out, suggesting a buildup of organic material (OM) prior to scouring of the bed sediments during ice break up. The dominant members of the microbial community that explained differences in N-processing rates belonged to the genera Crenothrix,Flavobacterium, and the family of Comamonadaceae. Our results suggest that biogeochemical processing rates in the bed sediments appear to be more coupled to hydrology, nutrient availability in the sediments, and microbial community composition rather than river nutrient concentrations at Pilot Station.

  14. Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

    NASA Astrophysics Data System (ADS)

    Repert, Deborah A.; Underwood, Jennifer C.; Smith, Richard L.; Song, Bongkeun

    2014-12-01

    Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sediment samples collected over distinct water cycle seasons. In conjunction, the microbial community composition in the bed sediments using genes involved in N-cycling (narG, napA, nosZ, and amoA) and 16S rRNA gene pyrosequences was examined. Temporal variation was observed in net N mineralization, nitrate uptake, and denitrification rate potentials and correlated strongly with sediment carbon (C) and extractable N content and microbial community composition rather than with river water nutrient concentrations. The C content of the bed sediment was notably impacted by the spring flood, ranging from 1.1% in the midst of an ice-jam to 0.1% immediately after ice-out, suggesting a buildup of organic material (OM) prior to scouring of the bed sediments during ice break up. The dominant members of the microbial community that explained differences in N-processing rates belonged to the genera Crenothrix, Flavobacterium, and the family of Comamonadaceae. Our results suggest that biogeochemical processing rates in the bed sediments appear to be more coupled to hydrology, nutrient availability in the sediments, and microbial community composition rather than river nutrient concentrations at Pilot Station.

  15. [Discussion on Quality Evaluation Method of Medical Device During Life-Cycle in Operation Based on the Analytic Hierarchy Process].

    PubMed

    Zheng, Caixian; Zheng, Kun; Shen, Yunming; Wu, Yunyun

    2016-01-01

    The content related to the quality during life-cycle in operation of medical device includes daily use, repair volume, preventive maintenance, quality control and adverse event monitoring. In view of this, the article aims at discussion on the quality evaluation method of medical devices during their life cycle in operation based on the Analytic Hierarchy Process (AHP). The presented method is proved to be effective by evaluating patient monitors as example. The method presented in can promote and guide the device quality control work, and it can provide valuable inputs to decisions about purchase of new device.

  16. ABSORPTION ANALYZER

    DOEpatents

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  17. Corrosion/Fragmentation of Layered Composite Cathode and Related Capacity/Voltage Fading during Cycling Process

    SciTech Connect

    Zheng, Jianming; Gu, Meng; Xiao, Jie; Zuo, Pengjian; Wang, Chong M.; Zhang, Jiguang

    2013-06-26

    Pristine and cycled layered structure cathode of Li[Li0.2Ni0.2M0.6]O2 samples are characterized by aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy. These analyses provide new insights on capacity/voltage fading mechanism of Li[Li0.2Ni0.2M0.6]O2. Sponge-like structure and fragment pieces were found on the surface of cathode after cycling. Mn2+ species and reduced Li content in the fragments caused significant capacity loss. These results also reveal the functional mechanism of surface coatings, e.g. AlF3, which can protect the electrode from etching by acidic species in the electrolyte, suppress cathode degradation and improve long-term cycling stability.

  18. Life cycle assessment of carbon capture and utilization from ammonia process in Mexico.

    PubMed

    Morales Mora, M A; Vergara, C Pretelín; Leiva, M A; Martínez Delgadillo, S A; Rosa-Domínguez, E R

    2016-12-01

    Post-combustion CO2 capture (PCC) of flue gas from an ammonia plant (AP) and the environmental performance of the carbon capture utilization (CCU) technology for greenhouse gas (GHG) emissions to an enhanced oil recovery (EOR) system in Mexico was performed as case study. The process simulations (PS) and life cycle assessment (LCA) were used as supporting tools to quantify the CO2 capture and their environmental impacts, respectively. Two scenarios were considered: 1) the AP with its shift and CO2 removal unit and 2) Scenario 1 plus PCC of the flue gas from the AP primary reformer (AP-2CO2) and the global warming (GW) impact. Also, the GW of the whole of a CO2-EOR project, from these two streams of captured CO2, was evaluated. Results show that 372,426 tCO2/year can be PCC from the flue gas of the primary reformer and 480,000 tons/y of capacity from the AP. The energy requirement for solvent regeneration is estimated to be 2.8 MJ/kgCO2 or a GW impact of 0.22 kgCO2e/kgCO2 captured. GW performances are 297.6 kgCO2e emitted/barrel (bbl) for scenario one, and 106.5 kgCO2e emitted/bbl for the second. The net emissions, in scenario one, were 0.52 tCO2e/bbl and 0.33 tCO2e/bbl in scenario two. Based on PS, this study could be used to evaluate the potential of CO2 capture of 4080 t/d of 4 ammonia plants. The integration of PS-LCA to a PCC study allows the applicability as methodological framework for the development of a cluster of projects in which of CO2 could be recycled back to fuel, chemical, petrochemical products or for enhanced oil recovery (EOR). With AP-2CO2, "CO2 emission free" ammonia production could be achieved.

  19. Overview of sleep: the neurologic processes of the sleep-wake cycle.

    PubMed

    Scammell, Thomas E

    2015-05-01

    Sleep problems are common in adults and should be treated to improve overall health and safety. To choose the best treatment for patients with sleep problems, clinicians should understand the sleep-wake cycle and the stages of rapid eye movement and non-rapid eye movement sleep as well as the neurologic pathways of sleep and wake systems. The sleep- and wake-promoting systems are mutually inhibitory, with the predominantly active system determining if a person is awake or asleep. The orexin system also plays an important role in the stabilization of the sleep-wake cycle. © Copyright 2015 Physicians Postgraduate Press, Inc.

  20. Life cycle energy and greenhouse gas emissions for an ethanol production process based on blue-green algae.

    PubMed

    Luo, Dexin; Hu, Zushou; Choi, Dong Gu; Thomas, Valerie M; Realff, Matthew J; Chance, Ronald R

    2010-11-15

    Ethanol can be produced via an intracellular photosynthetic process in cyanobacteria (blue-green algae), excreted through the cell walls, collected from closed photobioreactors as a dilute ethanol-in-water solution, and purified to fuel grade ethanol. This sequence forms the basis for a biofuel production process that is currently being examined for its commercial potential. In this paper, we calculate the life cycle energy and greenhouse gas emissions for three different system scenarios for this proposed ethanol production process, using process simulations and thermodynamic calculations. The energy required for ethanol separation increases rapidly for low initial concentrations of ethanol, and, unlike other biofuel systems, there is little waste biomass available to provide process heat and electricity to offset those energy requirements. The ethanol purification process is a major consumer of energy and a significant contributor to the carbon footprint. With a lead scenario based on a natural-gas-fueled combined heat and power system to provide process electricity and extra heat and conservative assumptions around the ethanol separation process, the net life cycle energy consumption, excluding photosynthesis, ranges from 0.55 MJ/MJ(EtOH) down to 0.20 MJ/ MJ(EtOH), and the net life cycle greenhouse gas emissions range from 29.8 g CO₂e/MJ(EtOH) down to 12.3 g CO₂e/MJ(EtOH) for initial ethanol concentrations from 0.5 wt % to 5 wt %. In comparison to gasoline, these predicted values represent 67% and 87% reductions in the carbon footprint for this ethanol fuel on a energy equivalent basis. Energy consumption and greenhouse gas emissions can be further reduced via employment of higher efficiency heat exchangers in ethanol purification and/ or with use of solar thermal for some of the process heat.

  1. Influence of polarization of the walnut plywood in the process of preparation on its water and moisture absorption

    NASA Astrophysics Data System (ADS)

    Zamilova, A. F.; Galikhanov, M. F.

    2016-09-01

    This paper demonstrates data on the effect of the polarization on the hygroscopic properties of plywood. The polarization of the plywood using a constant electric field can allow reducing slightly the amount of water and moisture absorption of the plywood material.

  2. Is the Critical Review Process Keeping Pace with the Growing Number of Life Cycle Assessments?

    EPA Science Inventory

    Environmental managers and government policy makers are becoming increasingly aware of the need to follow the holistic approach of Life Cycle Assessment (LCA) to move us in the right strategic direction to best achieve environmental sustainability. Along with this increasing real...

  3. Is the Critical Review Process Keeping Pace with the Growing Number of Life Cycle Assessments?

    EPA Science Inventory

    Environmental managers and government policy makers are becoming increasingly aware of the need to follow the holistic approach of Life Cycle Assessment (LCA) to move us in the right strategic direction to best achieve environmental sustainability. Along with this increasing real...

  4. A mechanistic treatment of the dominant soil nitrogen cycling processes: Model development, testing, and application

    USDA-ARS?s Scientific Manuscript database

    The development and initial application of a mechanistic model (TOUGHREACT-N) designed to characterize soil nitrogen (N) cycling and losses are described. The model couples advective and diffusive nutrient transport, multiple microbial biomass dynamics, and equilibrium and kinetic chemical reactions...

  5. Tall FIN formation for FINFET devices of 20nm and beyond using multi-cycles of passivation and etch processes

    NASA Astrophysics Data System (ADS)

    Choi, Dae-han; Yang, Dae Geun; Khanna, Puneet; Maeng, Chang; Hu, Owen; Shen, Hongliang; Wei, Andy; Kim, Sung

    2013-03-01

    In the past a few years, there has been a trend that non-planar field effect transistors (FETs) replace planar counterparts in semiconductor industry. One of critical and challenging processes to fabricate this non-planar device in bulk Si wafers is forming the array of tall Si fins with tight pitch that is used for gate channel as well as source and drain. Fin formation process typically involves deep Si etch using hard mask formed by double patterning technique (DPT). Traditional Si etch tends to results in intra-cell depth loading due to pitch walking and necking profile at the top portion of fins due to deep Si etch at small space. In addition, tall fins tend to stick to each other after post etch wet clean due to surface tension and hydrophilic fin sidewall. In this publication, 200nm tall fins with straight profile at the significant top portion of fins are demonstrated by using multi cycles of passivation and etch process. Physical and chemical parameters of each cycle were tuned respectively to generate straight top profile for gate channel control and smooth bottom profile to make it friendly for the following oxide gap fill process. Intra-cell and iso-dense depth loading is less than 3% of total depth. In addition, fin sticking is no longer observed after this multi cycle process. The exact mechanism is still under investigation but it is postulated that the fin sidewall surface condition has changed to be less hydrophilic due to multi cycle passivation.

  6. Collective behaviour in gene regulation: The cell is an oscillator, the cell cycle a developmental process

    PubMed Central

    Klevecz, Robert R.; Li, Caroline M.; Marcus, Ian; Frankel, Paul H.

    2010-01-01

    The finding of a genome-wide oscillation in transcription that gates cells into S phase and coordinates mitochondrial and metabolic functions has altered our understanding of how the cell cycle is timed and how stable cellular phenotypes are maintained. Here we present the evidence and arguments in support of the idea that everything oscillates, and the rationale for viewing the cell as an attractor from which deterministic noise can be tuned by appropriate coupling among the many feedback loops, or regulons, that make up the transcriptional-respiratory attractor –cycle (TRAC). The existence of this attractor also explains many of the dynamic macroscopic properties of the cell cycle and appears to be the timekeeping oscillator in both cell cycles and circadian rhythms. The path taken by this primordial oscillator in the course of differentiation or drug response may involve period doubling behavior. Evidence for a relatively high frequency timekeeping oscillator in yeast and mammalian cells comes from expression array analysis and GCMS in the case of yeast and primarily from macroscopic measures of phase response to perturbation in the case of mammalian cells. Low-amplitude, genome-wide oscillations, a ubiquitous but often unrecognized attribute of phenotype, could be a source of seemingly intractable biological noise in microarray and proteomic studies. These oscillations in transcript and protein levels and the repeated cycles of synthesis and degradation they require, represent a high energy cost to the cell which must, from an evolutionary point of view, be recovered as essential information. We suggest that the information contained in this genome wide oscillation is the dynamic code that organizes a stable phenotype from an otherwise passive genome. PMID:18410382

  7. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes.

    PubMed

    Wiesinger, R; Schade, U; Kleber, Ch; Schreiner, M

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  8. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    SciTech Connect

    Wiesinger, R.; Schade, U.; Kleber, Ch.; Schreiner, M.

    2014-06-15

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  9. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    NASA Astrophysics Data System (ADS)

    Wiesinger, R.; Schade, U.; Kleber, Ch.; Schreiner, M.

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  10. Investigation of quadratic electro-optic effects and electro-absorption process in GaN/AlGaN spherical quantum dot

    PubMed Central

    2014-01-01

    Quadratic electro-optic effects (QEOEs) and electro-absorption (EA) process in a GaN/AlGaN spherical quantum dot are theoretically investigated. It is found that the magnitude and resonant position of third-order nonlinear optical susceptibility depend on the nanostructure size and aluminum mole fraction. With increase of the well width and barrier potential, quadratic electro-optic effect and electro-absorption process nonlinear susceptibilities are decreased and blueshifted. The results show that the DC Kerr effect in this case is much larger than that in the bulk case. Finally, it is observed that QEOEs and EA susceptibilities decrease and broaden with the decrease of relaxation time. PMID:24646318

  11. Enhanced intestinal absorption activity and hepatoprotective effect of herpetrione via preparation of nanosuspensions using pH-dependent dissolving-precipitating/homogenization process.

    PubMed

    Shen, Baode; Jin, Shiying; Lv, Qingyuan; Jin, Shixiao; Yu, Chao; Yue, Pengfei; Han, Jin; Yuan, Hailong

    2013-09-01

    The main purpose of this study was to enhance the intestinal absorption activity and hepatoprotective effect of herpetrione by drug nanosuspensions. Herpetrione nanosuspensions (HNS) were prepared using pH-dependent dissolving-precipitating/homogenization process and then systematically characterized. The intestinal absorption activity of HNS were studied using the recirculating perfusion technique in comparison with herpetrione coarse suspensions (HCS) and pure herpetrione using the recirculating perfusion technique. The protective effect of HNS against acute liver injury induced by carbon tetrachloride (CCl4 ) in mice was also investigated and compared with that of HCS. The mean particle size of HNS was 269 ± 7 nm with a polydispersity index of 0.187 ± 0.021. The result of X-ray powder diffraction indicated that herpetrione was in amorphous state in both coarse powder and nanosuspensions. The intestinal absorption activity of HNS were superior to the HCS and pure herpetrione. As evidenced by the lowering of serum aminotransferase levels and the improvement of the degree of liver lesion, pretreatment with HNS markedly enhanced the hepatoprotective effect of herpetrione against acute liver injury induced by CCl4 in mice. HNS prepared using pH-dependent dissolving-precipitating/homogenization technique are able to significantly enhance the intestinal absorption activity and the hepatoprotective effect of herpetrione due to the particle size reduction. © 2013 Royal Pharmaceutical Society.

  12. Field experiments and numerical simulations of confined aquifer response to multi-cycle recharge-recovery process through a well

    NASA Astrophysics Data System (ADS)

    Wang, Jianxiu; Wu, Yuanbin; Zhang, Xingsheng; Liu, Yan; Yang, Tianliang; Feng, Bo

    2012-09-01

    SummaryShanghai is one of the cities suffering from land subsidence in China. Land subsidence has caused serious financial losses. Thus, artificial recharge measures have been adopted to compensate the drawdown in shallow, confined aquifers and thereby control land subsidence. In this study, a multi-cycle recharge-recovery field experiment was performed to investigate the response of a shallow, confined aquifer to artificial recharge through a well. In the experiment, a series of recharge-recovery cycles with different recharge volumes and durations, with and without artificial pressure, were performed. The water levels monitored in the recharge and observation wells indicated the response of the aquifer to the multi-cycle recharge-recovery process. Meanwhile, a finite-difference method (FDM) numerical model was established, and its parameters were obtained via a reversed numerical analysis on the experimental data. The responses of the shallow, confined aquifer to the multi-cycle recharge-recovery process were simulated in detail using the model. The calculation results showed that the water level dropped significantly when the recharge ended. Moreover, the efficiency of a multi-cycle recharge was found to be higher than that of a concentrated one under the same recharge volume and time. The relationship between recharge frequency and efficiency, expressed as H = 0.29498 f0.40163 and R2 = 0.97264, respectively, was obtained through the FDM numerical simulation. In the recharge intervals, the optimal recharge efficiency was achieved when the water level rose to 40% of the peak.

  13. Hollow-fiber membrane-based rapid pressure swing absorption

    SciTech Connect

    Bhaumik, S.; Majumdar, S.; Sirkar, K.K.

    1996-02-01

    A novel gas purification technique called rapid pressure swing absorption (RAPSAB) was developed by integrating the best features of membrane contacting, gas-liquid absorption, and pressure swing adsorption (PSA). In this cyclic separation process, a well-packed microporous hydrophobic hollow-fiber module was used to achieve nondispersive gas absorption from a high-pressure feed gas into a stationary absorbent liquid on the module shell side during a certain part of the cycle followed by desorption of absorbed gases from the liquid in the rest of the cycle. The total cycle time varies between 20 s and upwards. Separation of mixtures of N{sub 2} and CO{sub 2} (around 10%) where CO{sub 2} is the impurity to be removed was studied using absorbent liquids such as pure water and a 19.5% aqueous solution of diethanolamine (DEA). Three RAPSAB cycles studied differ in the absorption part. Virtually pure N{sub 2} streams were obtained with DEA as absorbent demonstrating the capability of bulk separation to very high levels of purification. Numerical models developed predict the extent of purification for pure water and the DEA solution for one of the simpler cycles. Model simulations describe the observed behavior well.

  14. Different types of nitrogen deposition show variable effects on the soil carbon cycle process of temperate forests.

    PubMed

    Du, Yuhan; Guo, Peng; Liu, Jianqiu; Wang, Chunyu; Yang, Ning; Jiao, Zhenxia

    2014-10-01

    Nitrogen (N) deposition significantly affects the soil carbon (C) cycle process of forests. However, the influence of different types of N on it still remained unclear. In this work, ammonium nitrate was selected as an inorganic N (IN) source, while urea and glycine were chosen as organic N (ON) sources. Different ratios of IN to ON (1 : 4, 2 : 3, 3 : 2, 4 : 1, and 5 : 0) were mixed with equal total amounts and then used to fertilize temperate forest soils for 2 years. Results showed that IN deposition inhibited soil C cycle processes, such as soil respiration, soil organic C decomposition, and enzymatic activities, and induced the accumulation of recalcitrant organic C. By contrast, ON deposition promoted these processes. Addition of ON also resulted in accelerated transformation of recalcitrant compounds into labile compounds and increased CO2 efflux. Meanwhile, greater ON deposition may convert C sequestration in forest soils into C source. These results indicated the importance of the IN to ON ratio in controlling the soil C cycle, which can consequently change the ecological effect of N deposition. © 2014 John Wiley & Sons Ltd.

  15. Simultaneous nitrogen and phosphorus removal in the sulfur cycle-associated Enhanced Biological Phosphorus Removal (EBPR) process.

    PubMed

    Wu, Di; Ekama, George A; Wang, Hai-Guang; Wei, Li; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2014-02-01

    Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) of freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4(2-)/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production and oxygen demand. Recently, the SANI(®) process has been expanded to include Enhanced Biological Phosphorus Removal (EBPR) in an alternating anaerobic/limited-oxygen (LOS-EBPR) aerobic sequencing batch reactor (SBR). This paper presents further development - an anaerobic/anoxic denitrifying sulfur cycle-associated EBPR, named as DS-EBPR, bioprocess in an alternating anaerobic/anoxic SBR for simultaneous removal of organics, nitrogen and phosphorus. The 211 day SBR operation confirmed the sulfur cycle-associated biological phosphorus uptake utilizing nitrate as electron acceptor. This new bioprocess cannot only reduce operation time but also enhance volumetric loading of SBR compared with the LOS-EBPR. The DS-EBPR process performed well at high temperatures of 30 °C and a high salinity of 20% seawater. A synergistic relationship may exist between sulfur cycle and biological phosphorus removal as the optimal ratio of P-release to SO4(2-)-reduction is close to 1.0 mg P/mg S. There were no conventional PAOs in the sludge.

  16. Changes in the carbon cycle of northern Eurasia simulated by process models

    NASA Astrophysics Data System (ADS)

    Rawlins, M. A.

    2013-12-01

    Pronounced warming across the northern high latitudes is impacting water and carbon cycles and raising concern over possible feedbacks to global climate. Recent model studied point toward a weakening of the terrestrial land carbon sink across the northern high latitudes, one notable manifestation of a warming Arctic. We explore links between regional climate and the carbon cycle using data from models participating in the Vulnerability of Permafrost Carbon Research Coordination Network (RCN). The domain of interest is the drainage basin within the Northern Eurasia Earth Science Partnership Initiative (NEESPI) region. Model outputs examined include gross primary production (GPP), heterotrophic respiration (RH), net ecosystem exchange (NEE), and total soil carbon storage. Mean flux budgets and their changes over the period 1960-2009 are calculated from the model estimates for the entire NEESPI region and for each major land cover category within the region. Use of an independent model, which captures well the spatial pattern in soil freeze/thaw dynamics, indicates that the reduction in permafrost extent over the NEESPI basin was 4-6% over recent decades. Modeled influences of permafrost thaw on the region's water and carbon cycles are evaluated in the context of recent measurements. Estimates of the flux of CO2 due to fire are also examined in order to better understand how these disturbances are altering regional carbon sink/source dynamics.

  17. Global redox cycle of biospheric carbon: Interaction of photosynthesis and earth crust processes.

    PubMed

    Ivlev, Alexander A

    2015-11-01

    A model of the natural global redox cycle of biospheric carbon is introduced. According to this model, carbon transfer between biosphere and geospheres is accompanied by a conversion of the oxidative forms, presented by CO2, bicarbonate and carbonate ions, into the reduced forms, produced in photosynthesis. The mechanism of carbon transfer is associated with two phases of movement of lithospheric plates. In the short-term orogenic phase, CO2 from the subduction (plates' collisions) zones fills the "atmosphere-hydrosphere" system, resulting in climate warming. In the long-term quiet (geosynclynal) phase, weathering and photosynthesis become dominant depleting the oxidative forms of carbon. The above asymmetric periodicity exerts an impact on climate, biodiversity, distribution of organic matter in sedimentary deposits, etc. Along with photosynthesis expansion, the redox carbon cycle undergoes its development until it reaches the ecological compensation point, at which CO2 is depleted to the level critical to support the growth and reproduction of plants. This occurred in the Permo-Carboniferous time and in the Neogene. Shorter-term perturbations of the global carbon cycle in the form of glacial-interglacial oscillations appear near the ecological compensation point. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Process contributions of Australian ecosystems to interannual variations in the carbon cycle

    NASA Astrophysics Data System (ADS)

    Haverd, Vanessa; Smith, Benjamin; Trudinger, Cathy

    2016-05-01

    New evidence is emerging that semi-arid ecosystems dominate interannual variability (IAV) of the global carbon cycle, largely via fluctuating water availability associated with El Niño/Southern Oscillation. Recent evidence from global terrestrial biosphere modelling and satellite-based inversion of atmospheric CO2 point to a large role of Australian ecosystems in global carbon cycle variability, including a large contribution from Australia to the record land sink of 2011. However the specific mechanisms governing this variability, and their bioclimatic distribution within Australia, have not been identified. Here we provide a regional assessment, based on best available observational data, of IAV in the Australian terrestrial carbon cycle and the role of Australia in the record land sink anomaly of 2011. We find that IAV in Australian net carbon uptake is dominated by semi-arid ecosystems in the east of the continent, whereas the 2011 anomaly was more uniformly spread across most of the continent. Further, and in contrast to global modelling results suggesting that IAV in Australian net carbon uptake is amplified by lags between production and decomposition, we find that, at continental scale, annual variations in production are dampened by annual variations in decomposition, with both fluxes responding positively to precipitation anomalies.

  19. A comparative life cycle assessment of hybrid osmotic dilution desalination and established seawater desalination and wastewater reclamation processes.

    PubMed

    Hancock, Nathan T; Black, Nathan D; Cath, Tzahi Y

    2012-03-15

    The purpose of this study was to determine the comparative environmental impacts of coupled seawater desalination and water reclamation using a novel hybrid system that consist of an osmotically driven membrane process and established membrane desalination technologies. A comparative life cycle assessment methodology was used to differentiate between a novel hybrid process consisting of forward osmosis (FO) operated in osmotic dilution (ODN) mode and seawater reverse osmosis (SWRO), and two other processes: a stand alone conventional SWRO desalination system, and a combined SWRO and dual barrier impaired water purification system consisting of nanofiltration followed by reverse osmosis. Each process was evaluated using ten baseline impact categories. It was demonstrated that from a life cycle perspective two hurdles exist to further development of the ODN-SWRO process: module design of FO membranes and cleaning intensity of the FO membranes. System optimization analysis revealed that doubling FO membrane packing density, tripling FO membrane permeability, and optimizing system operation, all of which are technically feasible at the time of this publication, could reduce the environmental impact of the hybrid ODN-SWRO process compared to SWRO by more than 25%; yet, novel hybrid nanofiltration-RO treatment of seawater and wastewater can achieve almost similar levels of environmental impact.

  20. MSG-7: molecular absorption processes related to the penetration of ultraviolet solar radiation into the middle atmosphere

    SciTech Connect

    Frederick, J.E.; Blake, A.J.; Freeman, D.E.; Nicholls, R.W.; Ogawa, T.

    1983-07-01

    The information presently available on the absorption cross sections of O2 and O3 with attention to the application of these data in middle atmospheric science is reviewed. The cross sections values reported by different groups are intercompared in tabular form where feasible, and specific values are recommended when there is a basis for preferring a particular set of results over other available data. When no such basis exists, the differences among published cross sections then serve to indicate a range of uncertainty. In these cases the need for additional work is indicated. Specific topics addressed are the absorption of molecular oxygen at Lyman alpha, in the Schumann-Runge continuum, in the Schumann-Runge bands, and in the Herzberg continuum. For ozone, the Hartley and Huggins bands are considered.

  1. MSG-7: Molecular absorption processes related to the penetration of ultraviolet solar radiation into the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Frederick, J. E.; Blake, A. J.; Freeman, D. E.; Nicholls, R. W.; Ogawa, T.; Simon, P. C.

    1983-01-01

    The information presently available on the absorption cross sections of O2 and O3 with attention to the application of these data in middle atmospheric science is reviewed. The cross sections values reported by different groups are intercompared in tabular form where feasible, and specific values are recommended when there is a basis for preferring a particular set of results over other available data. When no such basis exists, the differences among published cross sections then serve to indicate a range of uncertainty. In these cases the need for additional work is indicated. Specific topics addressed are the absorption of molecular oxygen at Lyman alpha, in the Schumann-Runge continuum, in the Schumann-Runge bands, and in the Herzberg continuum. For ozone, the Hartley and Huggins bands are considered.

  2. Comparative Study of the Effects of Long and Short Term Biological Processes on the Cycling of Colloidal Trace Metals

    NASA Astrophysics Data System (ADS)

    Pinedo, P.; Sanudo-Wilhelmy, S. A.; West, A.

    2013-05-01

    Nanoparticle (or colloids), with sizes operationally defined as ranging from 1nm to 1000nm diameter, are thought to play an important role in metal cycling in the ocean due to their high surface area to volume ratio and abundance in marine systems. In coastal waters, the bulk of marine nanoparticles are organic, so short and long term biological processes are expected to influence the dynamics of these types of particles in marine environments. This is, in turn, expected to influence metal concentrations. Here we selected two different environments to study the influence of long-term biological events (phytoplankton blooms) and short-term biological events (diel cycles of photosynthesis and respiration) on the cycling of colloidal trace metals. We focus on Cu and Fe, both biogeochemically important metals but with differing colloidal behavior. Long term processes (West Neck Bay): A bay (West Neck Bay, Long Island) with predictable natural phytoplankton blooms, but with limited inputs of freshwater, nutrients and metals, was selected to study the partitioning of Cu and Fe between colloidal and soluble pools over the course of a bloom. During the bloom, there was a significant build-up of Cu associated with DOM accumulation and a removal of Fe via particle stripping. Fraction-specific metal concentrations, and metal accumulation and removal rates, were found to be significantly correlated with chlorophyll-a concentration and with dissolved organic matter (DOM). Short term processes (Catalina Island): To identify the cyclical variation in metal speciation during diel (24-hour) cycles of photosynthesis and respiration, we conducted a study off Catalina Island, a pristine environment where trace metal cycling is solely controlled by biological processes and changes in the phytoplankton community are well characterized. The speciation of Fe between soluble and colloidal pools showed that Fe has a high affinity for colloidal material and that the distribution between

  3. Thermochemical water-splitting cycle, bench-scale investigations, and process engineering. Final report, February 1977-December 31, 1981

    SciTech Connect

    Norman, J.H.; Besenbruch, G.E.; Brown, L.C.; O'Keefe, D.R.; Allen, C.L.

    1982-05-01

    The sulfur-iodine water-splitting cycle is characterized by the following three reactions: 2H/sub 2/O + SO/sub 2/ + I/sub 2/ ..-->.. H/sub 2/SO/sub 4/ + 2HI; H/sub 2/SO/sub 4/ ..-->.. H/sub 2/O + SO/sub 2/ + 1/2 O/sub 2/; and 2HI ..-->.. H/sub 2/ + I/sub 2/. This cycle was developed at General Atomic after several critical features in the above reactions were discovered. These involved phase separations, catalytic reactions, etc. Estimates of the energy efficiency of this economically reasonable advanced state-of-the-art processing unit produced sufficiently high values (to approx.47%) to warrant cycle development effort. The DOE contract was largely directed toward the engineering development of this cycle, including a small demonstration unit (CLCD), a bench-scale unit, engineering design, and costing. The work has resulted in a design that is projected to produce H/sub 2/ at prices not yet generally competitive with fossil-fuel-produced H/sub 2/ but are projected to be favorably competitive with respect to H/sub 2/ from fossil fuels in the future.

  4. Long chain branching as an innovative up-cycling process of polypropylene post-consumer waste - Possibilities and limitations.

    PubMed

    Kamleitner, Florian; Duscher, Bernadette; Koch, Thomas; Knaus, Simone; Archodoulaki, Vasiliki-Maria

    2017-07-20

    Long chain branching (LCB) was used the first time as an innovative tool for value adding to PP from household post-consumer waste. Due to the highly improved melt properties, the possible application profile is extended and not only a "re-cycling" process, even a real "up-cycling" is presented. The used PP was collected from commingled household polyolefin waste, which contained different types of PP and macromolecular impurities such as 10% of polyethylene with high density (PE-HD). In addition, a single PP waste fraction from cleaned beverage and yoghurt cups was manually sorted. The up-cycled PP from single polymer waste, as well as the post-consumer blend, showed pronounced strain hardening and increased melt strength, which was comparable to LCB-PP prepared from virgin PP. However, the up-cycled post-consumer blend showed weaker mechanical performance especially low elongation at break due to PE-HD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Design, construction, and operation of a life-cycle test system for the evaluation of flue gas cleanup processes

    SciTech Connect

    Pennline, H.W.; Yeh, James T.; Hoffman, J.S.; Longton, E.J.; Vore, P.A.; Resnik, K.P.; Gromicko, F.N.

    1995-12-01

    The Pittsburgh Energy Technology Center of the US Department of Energy has designed, constructed, and operated a Life-Cycle Test Systems (LCTS) that will be used primarily for the investigation of dry, regenerable sorbent flue gas cleanup processes. Sorbent continuously cycles from an absorber reactor where the pollutants are removed from the flue gas, to a regenerator reactor where the activity of the spent sorbent is restored and a usable by-product stream of gas is produced. The LCTS will initially be used to evaluate the Moving-Bed Copper Oxide Process by determining the effects of various process parameters on SO{sub 2} and NO{sub x} removals. The purpose of this paper is to document the design rationale and details, the reactor/component/instrument installation, and the initial performance of the system. Although the Moving-Bed Copper Oxide Process will be investigated initially, the design of the LCTS evolved to make the system a multipurpose, versatile research facility. Thus, the unit can be used to investigate various other processes for pollution abatement of SO{sub 2}, NO{sub x}, particulates, air toxics, and/or other pollutants.

  6. Life cycle assessment of medium-density fiberboard (MDF) manufacturing process in Brazil.

    PubMed

    Piekarski, Cassiano Moro; de Francisco, Antonio Carlos; da Luz, Leila Mendes; Kovaleski, João Luiz; Silva, Diogo Aparecido Lopes

    2017-01-01

    Brazil is one of the largest producers of medium-density fibreboard (MDF) in the world, and also the MDF has the highest domestic consumption and production rate in the country. MDF applications are highlighted into residential and commercial furniture design and also a wide participation in the building sector. This study aimed to propose ways of improving the environmental cradle-to-gate life-cycle of one cubic meter MDF panel by means of a life-cycle assessment (LCA) study. Complying with requirements of ISO 14040 and 14,044 standards, different MDF manufacturing scenarios were modelled using Umberto® v.5.6 software and the Ecoinvent v.2.2 life-cycle inventory (LCI) database for the Brazilian context. Environmental and human health impacts were assessed by using the CML (2001) and USEtox (2008) methods. The evaluated impact categories were: acidification, global warming, ozone layer depletion, abiotic resource depletion, photochemical formation of tropospheric ozone, ecotoxicity, eutrophication and human toxicity. Results identified the following hotspots: gas consumption at the thermal plant, urea-formaldehyde resin, power consumption, wood chip consumption and wood chip transportation to the plant. The improvement scenario proposals comprised the following actions: eliminate natural gas consumption at the thermal plant, reduce electrical power consumption, reduce or replace urea-formaldehyde resin consumption, reduce wood consumption and minimize the distance to wood chip suppliers. The proposed actions were analysed to verify the influence of each action on the set of impact categories. Among the results, it can be noted that a joint action of the proposed improvements can result in a total reduction of up to 38.5% of impacts to OD, 34.4% to AD, 31.2% to ET, and 30.4% to HT. Finally, MDF was compared with particleboard production in Brazil, and additional opportunities to improve the MDF environmental profile were identified.

  7. Intercellular Variability in Protein Levels from Stochastic Expression and Noisy Cell Cycle Processes.

    PubMed

    Soltani, Mohammad; Vargas-Garcia, Cesar A; Antunes, Duarte; Singh, Abhyudai

    2016-08-01

    Inside individual cells, expression of genes is inherently stochastic and manifests as cell-to-cell variability or noise in protein copy numbers. Since proteins half-lives can be comparable to the cell-cycle length, randomness in cell-division times generates additional intercellular variability in protein levels. Moreover, as many mRNA/protein species are expressed at low-copy numbers, errors incurred in partitioning of molecules between two daughter cells are significant. We derive analytical formulas for the total noise in protein levels when the cell-cycle duration follows a general class of probability distributions. Using a novel hybrid approach the total noise is decomposed into components arising from i) stochastic expression; ii) partitioning errors at the time of cell division and iii) random cell-division events. These formulas reveal that random cell-division times not only generate additional extrinsic noise, but also critically affect the mean protein copy numbers and intrinsic noise components. Counter intuitively, in some parameter regimes, noise in protein levels can decrease as cell-division times become more stochastic. Computations are extended to consider genome duplication, where transcription rate is increased at a random point in the cell cycle. We systematically investigate how the timing of genome duplication influences different protein noise components. Intriguingly, results show that noise contribution from stochastic expression is minimized at an optimal genome-duplication time. Our theoretical results motivate new experimental methods for decomposing protein noise levels from synchronized and asynchronized single-cell expression data. Characterizing the contributions of individual noise mechanisms will lead to precise estimates of gene expression parameters and techniques for altering stochasticity to change phenotype of individual cells.

  8. Intercellular Variability in Protein Levels from Stochastic Expression and Noisy Cell Cycle Processes

    PubMed Central

    Soltani, Mohammad; Vargas-Garcia, Cesar A.; Antunes, Duarte; Singh, Abhyudai

    2016-01-01

    Inside individual cells, expression of genes is inherently stochastic and manifests as cell-to-cell variability or noise in protein copy numbers. Since proteins half-lives can be comparable to the cell-cycle length, randomness in cell-division times generates additional intercellular variability in protein levels. Moreover, as many mRNA/protein species are expressed at low-copy numbers, errors incurred in partitioning of molecules between two daughter cells are significant. We derive analytical formulas for the total noise in protein levels when the cell-cycle duration follows a general class of probability distributions. Using a novel hybrid approach the total noise is decomposed into components arising from i) stochastic expression; ii) partitioning errors at the time of cell division and iii) random cell-division events. These formulas reveal that random cell-division times not only generate additional extrinsic noise, but also critically affect the mean protein copy numbers and intrinsic noise components. Counter intuitively, in some parameter regimes, noise in protein levels can decrease as cell-division times become more stochastic. Computations are extended to consider genome duplication, where transcription rate is increased at a random point in the cell cycle. We systematically investigate how the timing of genome duplication influences different protein noise components. Intriguingly, results show that noise contribution from stochastic expression is minimized at an optimal genome-duplication time. Our theoretical results motivate new experimental methods for decomposing protein noise levels from synchronized and asynchronized single-cell expression data. Characterizing the contributions of individual noise mechanisms will lead to precise estimates of gene expression parameters and techniques for altering stochasticity to change phenotype of individual cells. PMID:27536771

  9. [A Medical Devices Management Information System Supporting Full Life-Cycle Process Management].

    PubMed

    Tang, Guoping; Hu, Liang

    2015-07-01

    Medical equipments are essential supplies to carry out medical work. How to ensure the safety and reliability of the medical equipments in diagnosis, and reduce procurement and maintenance costs is a topic of concern to everyone. In this paper, product lifecycle management (PLM) and enterprise resource planning (ERP) are cited to establish a lifecycle management information system. Through integrative and analysis of the various stages of the relevant data in life-cycle, it can ensure safety and reliability of medical equipments in the operation and provide the convincing data for meticulous management.

  10. Peatlands and the Carbon Cycle: From Local Processes to Global Implications

    NASA Astrophysics Data System (ADS)

    Wieder, R. Kelman; Canadell, Josep; Limpens, Juul; Moore, Tim; Roulet, Nigel; Schaepman-Strub, Gabriela

    2007-07-01

    Boreal and subarctic peatlands cover about 3% of the Earth's land surface and store 15-30% of the world's soil carbon (200-400 petagrams) as peat. This large C pool, in addition to C in Arctic soils, lies at higher latitudes that are experiencing ongoing climate change. Tropical peatlands also contain large C reservoirs, the stability of which is threatened by ongoing land use change. In response to a call from PeatNet (a National Science Foundation-supported research coordination network), Juul Limpens and Gabriela Schaepman-Strub proposed a small workshop on peatland C cycling, an idea that morphed into a meeting with 180 participants from 18 countries,

  11. Role of the particle’s stepping cycle in an asymmetric exclusion process: a model of mRNA translation

    PubMed Central

    Ciandrini, L.; Stansfield, I.; Romano, M. C.

    2013-01-01

    Messenger RNA translation is often studied by means of statistical-mechanical models based on the Asymmetric Simple Exclusion Process (ASEP), which considers hopping particles (the ribosomes) on a lattice (the polynucleotide chain). In this work we extend this class of models and consider the two fundamental steps of the ribosome’s biochemical cycle following a coarse-grained perspective. In order to achieve a better understanding of the underlying biological processes and compare the theoretical predictions with experimental results, we provide a description lying between the minimal ASEP-like models and the more detailed models, which are analytically hard to treat. We use a mean-field approach to study the dynamics of particles associated with an internal stepping cycle. In this framework it is possible to characterize analytically different phases of the system (high density, low density or maximal current phase). Crucially, we show that the transitions between these different phases occur at different parameter values than the equivalent transitions in a standard ASEP, indicating the importance of including the two fundamental steps of the ribosome’s biochemical cycle into the model. PMID:20866258

  12. Role of Protein Phosphorylation in the Regulation of Cell Cycle and DNA-Related Processes in Bacteria

    PubMed Central

    Garcia-Garcia, Transito; Poncet, Sandrine; Derouiche, Abderahmane; Shi, Lei; Mijakovic, Ivan; Noirot-Gros, Marie-Françoise

    2016-01-01

    In all living organisms, the phosphorylation of proteins modulates various aspects of their functionalities. In eukaryotes, protein phosphorylation plays a key role in cell signaling, gene expression, and differentiation. Protein phosphorylation is also involved in the global control of DNA replication during the cell cycle, as well as in the mechanisms that cope with stress-induced replication blocks. Similar to eukaryotes, bacteria use Hanks-type kinases and phosphatases for signal transduction, and protein phosphorylation is involved in numerous cellular processes. However, it remains unclear whether protein phosphorylation in bacteria can also regulate the activity of proteins involved in DNA-mediated processes such as DNA replication or repair. Accumulating evidence supported by functional and biochemical studies suggests that phospho-regulatory mechanisms also take place during the bacterial cell cycle. Recent phosphoproteomics and interactomics studies identified numerous phosphoproteins involved in various aspect of DNA metabolism strongly supporting the existence of such level of regulation in bacteria. Similar to eukaryotes, bacterial scaffolding-like proteins emerged as platforms for kinase activation and signaling. This review reports the current knowledge on the phosphorylation of proteins involved in the maintenance of genome integrity and the regulation of cell cycle in bacteria that reveals surprising similarities to eukaryotes. PMID:26909079

  13. Role of Protein Phosphorylation in the Regulation of Cell Cycle and DNA-Related Processes in Bacteria.

    PubMed

    Garcia-Garcia, Transito; Poncet, Sandrine; Derouiche, Abderahmane; Shi, Lei; Mijakovic, Ivan; Noirot-Gros, Marie-Françoise

    2016-01-01

    In all living organisms, the phosphorylation of proteins modulates various aspects of their functionalities. In eukaryotes, protein phosphorylation plays a key role in cell signaling, gene expression, and differentiation. Protein phosphorylation is also involved in the global control of DNA replication during the cell cycle, as well as in the mechanisms that cope with stress-induced replication blocks. Similar to eukaryotes, bacteria use Hanks-type kinases and phosphatases for signal transduction, and protein phosphorylation is involved in numerous cellular processes. However, it remains unclear whether protein phosphorylation in bacteria can also regulate the activity of proteins involved in DNA-mediated processes such as DNA replication or repair. Accumulating evidence supported by functional and biochemical studies suggests that phospho-regulatory mechanisms also take place during the bacterial cell cycle. Recent phosphoproteomics and interactomics studies identified numerous phosphoproteins involved in various aspect of DNA metabolism strongly supporting the existence of such level of regulation in bacteria. Similar to eukaryotes, bacterial scaffolding-like proteins emerged as platforms for kinase activation and signaling. This review reports the current knowledge on the phosphorylation of proteins involved in the maintenance of genome integrity and the regulation of cell cycle in bacteria that reveals surprising similarities to eukaryotes.

  14. Role of the particle's stepping cycle in an asymmetric exclusion process: A model of mRNA translation

    NASA Astrophysics Data System (ADS)

    Ciandrini, L.; Stansfield, I.; Romano, M. C.

    2010-05-01

    Messenger RNA translation is often studied by means of statistical-mechanical models based on the asymmetric simple exclusion process (ASEP), which considers hopping particles (the ribosomes) on a lattice (the polynucleotide chain). In this work we extend this class of models and consider the two fundamental steps of the ribosome’s biochemical cycle following a coarse-grained perspective. In order to achieve a better understanding of the underlying biological processes and compare the theoretical predictions with experimental results, we provide a description lying between the minimal ASEP-like models and the more detailed models, which are analytically hard to treat. We use a mean-field approach to study the dynamics of particles associated with an internal stepping cycle. In this framework it is possible to characterize analytically different phases of the system (high density, low density or maximal current phase). Crucially, we show that the transitions between these different phases occur at different parameter values than the equivalent transitions in a standard ASEP, indicating the importance of including the two fundamental steps of the ribosome’s biochemical cycle into the model.

  15. Understanding the influence of orography on the precipitation diurnal cycle and the associated atmospheric processes in the central Andes

    NASA Astrophysics Data System (ADS)

    Junquas, C.; Takahashi, K.; Condom, T.; Espinoza, J.-C.; Chavez, S.; Sicart, J.-E.; Lebel, T.

    2017-08-01

    In the tropical Andes, the identification of the present synoptic mechanisms associated with the diurnal cycle of precipitation and its interaction with orography is a key step to understand how the atmospheric circulation influences the patterns of precipitation variability on longer time-scales. In particular we aim to better understand the combination of the local and regional mechanisms controlling the diurnal cycle of summertime (DJF) precipitation in the Northern Central Andes (NCA) region of Southern Peru. A climatology of the diurnal cycle is obtained from 15 wet seasons (2000-2014) of 3-hourly TRMM-3B42 data (0.25° × 0.25°) and swath data from the TRMM-2A25 precipitation radar product (5 km × 5 km). The main findings are: (1) in the NCA region, the diurnal cycle shows a maximum precipitation occurring during the day (night) in the western (eastern) side of the Andes highlands, (2) in the valleys of the Cuzco region and in the Amazon slope of the Andes the maximum (minimum) precipitation occurs during the night (day). The WRF (Weather Research and Forecasting) regional atmospheric model is used to simulate the mean diurnal cycle in the NCA region for the same period at 27 km and 9 km horizontal grid spacing and 3-hourly output, and at 3 km only for the month of January 2010 in the Cuzco valleys. Sensitivity experiments were also performed to investigate the effect of the topography on the observed rainfall patterns. The model reproduces the main diurnal precipitation features. The main atmospheric processes identified are: (1) the presence of a regional-scale cyclonic circulation strengthening during the afternoon, (2) diurnal thermally driven circulations at local scale, including upslope (downslope) wind and moisture transport during the day (night), (3) channelization of the upslope moisture transport from the Amazon along the Apurimac valleys toward the western part of the cordillera.

  16. Evaluating new processes and concepts for energy and resource recovery from municipal wastewater with life cycle assessment.

    PubMed

    Remy, C; Boulestreau, M; Warneke, J; Jossa, P; Kabbe, C; Lesjean, B

    2016-01-01

    Energy and resource recovery from municipal wastewater is a pre-requisite for an efficient and sustainable water management in cities of the future. However, a sound evaluation of available processes and pathways is required to identify opportunities and short-comings of the different options and reveal synergies and potentials for optimization. For evaluating environmental impacts in a holistic view, the tool of life cycle assessment (LCA, ISO 14040/44) is suitable to characterize and quantify the direct and indirect effects of new processes and concepts. This paper gives an overview of four new processes and concepts for upgrading existing wastewater treatment plants towards energy positive and resource efficient wastewater treatment, based upon an evaluation of their environmental impacts with LCA using data from pilot and full-scale assessments of the considered processes.

  17. Laser materials processing of complex components: from reverse engineering via automated beam path generation to short process development cycles

    NASA Astrophysics Data System (ADS)

    Görgl, Richard; Brandstätter, Elmar

    2017-01-01

    The article presents an overview of what is possible nowadays in the field of laser materials processing. The state of the art in the complete process chain is shown, starting with the generation of a specific components CAD data and continuing with the automated motion path generation for the laser head carried by a CNC or robot system. Application examples from laser cladding and laser-based additive manufacturing are given.

  18. Laser materials processing of complex components. From reverse engineering via automated beam path generation to short process development cycles.

    NASA Astrophysics Data System (ADS)

    Görgl, R.; Brandstätter, E.

    2016-03-01

    The article presents an overview of what is possible nowadays in the field of laser materials processing. The state of the art in the complete process chain is shown, starting with the generation of a specific components CAD data and continuing with the automated motion path generation for the laser head carried by a CNC or robot system. Application examples from laser welding, laser cladding and additive laser manufacturing are given.

  19. Improvement in magnetic and microwave absorption properties of nano-Fe3O4@CFs composites using a modified multi-step EPD process

    NASA Astrophysics Data System (ADS)

    Movassagh-Alanagh, Farid; Bordbar Khiabani, Aidin; Salimkhani, Hamed

    2017-10-01

    In this research, structural, magnetic and microwave absorption properties of multifunctional nano-Fe3O4@carbon fibers (CFs) composites in the frequency range of 8.2-18 GHz were investigated. The nano-Fe3O4 particles (30 nm) were successfully prepared using co-precipitation method. These particles were then deposited on CFs using two conventional and modified multi-step electrophoretic deposition (EPD) processes to investigate the contributing effects of uniformity of coating on their magnetic and microwave absorption properties. The magnetic properties measurements represented that the coercivity (Hc), saturation magnetization (Ms) and residual magnetization (Mrs) values of the coated CFs using the conventional EPD process were 531.4 Oe, 15.2 emu/g and 5.2 emu/g, respectively, while for the CFs coated with modified EPD process these values were 167.8 Oe, 33.1 emu/g and 1.7 emu/g, respectively. It was found that by employing conventional EPD process, the maximum reflection loss (RL) of -9.87 dB was obtained for the composite containing 20 wt.% nano-Fe3O4@CFs and 80 wt.% epoxy-resin with the thickness of 2 mm, while by using the modified multi-step EPD process, due to enhancement of deposited coating quality, the achieved maximum RL was approximately increased by -0.64 dB and reached to -10.51 dB with an effective absorption bandwidth of about 4 GHz for the similar sample with the same thickness and weight ratio of nano-Fe3O4@CFs composites to epoxy 828.

  20. A spatiotemporal structure: common to subatomic systems, biological processes, and economic cycles

    NASA Astrophysics Data System (ADS)

    Naitoh, Ken

    2012-03-01

    A theoretical model derived based on a quasi-stability concept applied to momentum conservation (Naitoh, JJIAM, 2001, Artificial Life Robotics, 2008, 2010) has revealed the spatial structure of various systems. This model explains the reason why particles such as biological cells, nitrogenous bases, and liquid droplets have bimodal size ratios of about 2:3 and 1:1. This paper shows that the same theory holds true for several levels of parcels from baryons to stars in the cosmos: specifically, at the levels of nuclear force, van der Waals force, surface tension, and the force of gravity. A higher order of analysis clarifies other asymmetric ratios related to the halo structure seen in atoms and amino acids. We will also show that our minimum hypercycle theory for explaining the morphogenetic cycle (Naitoh, Artificial Life Robotics, 2008) reveals other temporal cycles such as those of economic systems and the circadian clock as well as the fundamental neural network pattern (topological pattern). Finally, a universal equation describing the spatiotemporal structure of several systems will be derived, which also leads to a general concept of quasi-stability.

  1. Life cycle assessment of cellulose nanofibrils production by mechanical treatment and two different pretreatment processes.

    PubMed

    Arvidsson, Rickard; Nguyen, Duong; Svanström, Magdalena

    2015-06-02

    Nanocellulose is a bionanomaterial with many promising applications, but high energy use in production has been described as a potential obstacle for future use. In fact, life cycle assessment studies have indicated high life cycle energy use for nanocellulose. In this study, we assess the cradle-to-gate environmental impacts of three production routes for a particular type of nanocellulose called cellulose nanofibrils (CNF) made from wood pulp. The three production routes are (1) the enzymatic production route, which includes an enzymatic pretreatment, (2) the carboxymethylation route, which includes a carboxymethylation pretreatment, and (3) one route without pretreatment, here called the no pretreatment route. The results show that CNF produced via the carboxymethylation route clearly has the highest environmental impacts due to large use of solvents made from crude oil. The enzymatic and no pretreatment routes both have lower environmental impacts, of similar magnitude. A sensitivity analysis showed that the no pretreatment route was sensitive to the electricity mix, and the carboxymethylation route to solvent recovery. When comparing the results to those of other carbon nanomaterials, it was shown that in particular CNF produced via the enzymatic and no pretreatment routes had comparatively low environmental impacts.

  2. Kinetic-quantum chemical model for catalytic cycles: the Haber-Bosch process and the effect of reagent concentration.

    PubMed

    Kozuch, Sebastian; Shaik, Sason

    2008-07-03

    A combined kinetic-quantum chemical model is developed with the goal of estimating in a straightforward way the turnover frequency (TOF) of catalytic cycles, based on the state energies obtained by quantum chemical calculations. We describe how the apparent activation energy of the whole cycle, so-called energetic span (delta E), is influenced by the energy levels of two species: the TOF determining transition state (TDTS) and the TOF determining intermediate (TDI). Because these key species need not be adjoining states, we conclude that for catalysis there are no rate-determining steps, only rate determining states. In addition, we add here the influence of reactants concentrations. And, finally, the model is applied to the Haber-Bosch process of ammonia synthesis, for which we show how to calculate which catalyst will be the most effective under specific reagents conditions.

  3. Development of pyro-processing technology at CRIEPI for carving out the future of nuclear fuel cycle

    SciTech Connect

    Iizuka, M.; Koyama, T.; Sakamura, Y.; Uozumi, K.; Fujihata, K.; Kato, T.; Murakami, T.; Tsukada, T.; Glatz, J.P.

    2013-07-01

    Pyro-processing has been attracting increasing attention as a promising candidate as an advanced nuclear fuel cycle technology. It provides economic advantage as well as reduction in proliferation risk and burden of long live radioactive waste, especially when it is combined with advanced fuels such as metallic or nitride fuel which gives excellent burning efficiency of minor actinides (MA). CRIEPI has been developing pyro-processing technology since late eighties with both domestic and international collaborations. In the early stage, electrochemical and thermodynamic properties in LiCl-KCl eutectic melt, and fundamental feasibility of core technology like electrorefining were chiefly investigated. Currently, stress in the process chemistry development is also placed on supporting technologies, such as treatment of anode residue and high temperature distillation for cathode product from electrorefining, and so on. Waste treatment process development, such as studies on adsorption behavior of various FP elements into zeolite and conditions for the fabrication of glass-bonded sodalite waste form, are steadily improved as well. In parallel, dedicated pyro-processing equipment such as zeolite column for treatment of spent electro-refiner salt is currently in progress. Recently, an integrated engineering-scale fuel cycle tests were performed funded by Japanese government (MEXT) as an important step before proceeding to large scale hot demonstration of pyro-processing. Oxide fuels can be readily introduced into the pyro-processing by reducing them to metals by adoption of electrochemical reduction technique. Making use of this advantage, the pyro-processing is currently under preliminary evaluation for its applicability to the treatment of the corium, mainly consisting of (U,Zr)O{sub 2}, formed in different composition during the accident of the Fukushima Daiichi nuclear power plant. (authors)

  4. Bench-Scale Development of a Hybrid Membrane-Absorption CO{sub 2} Capture Process: Preliminary Cost Assessment

    SciTech Connect

    Freeman, Brice; Kniep, Jay; Pingjiao, Hao; Baker, Richard; Rochelle, Gary; Chen, Eric; Frailie, Peter; Ding, Junyuan; Zhang, Yue

    2014-03-31

    This report describes a study of capture costs for a hybrid membrane-absorption capture system based on Membrane Technology and Research, Inc. (MTR)’s low-pressure membrane contactors and the University of Texas at Austin’s 5 m piperazine (PZ) Advanced Flash Stripper (AFS; 5 m PZ AFS) based CO2 capture system. The report is submitted for NETL review, and may be superseded by a final topical report on this topic that will be submitted to satisfy the Task 2 report requirement of the current project (DE-FE0013118).

  5. In situ Observation of Formation Process of Negative Electron Affinity Surface of GaAs by Surface Photo-Absorption

    NASA Astrophysics Data System (ADS)

    Hayase, Kazuya; Nishitani, Tomohiro; Suzuki, Katsunari; Imai, Hironobu; Hasegawa, Jun-ichi; Namba, Daiki; Meguro, Takashi

    2013-06-01

    We have used surface photo-absorption (SPA) to investigate the formation of negative electron affinity (NEA) surfaces on p-GaAs during the Yo-Yo method, under an alternating supply of Cs and O2. The SPA spectra showed that the surface during the first Cs step was different from those in the following Cs and O2 steps. This suggests that the surface structure did not change after the initial surface was formed, indicating that there could be two Cs adsorption sites on the GaAs surface, which is different from previously proposed models.

  6. Substrate having high absorptance and emitance black electroless nicel coating and a process for producing the same

    SciTech Connect

    Greeson, R.; Geikas, G. I.

    1985-04-16

    A substrate having high absorptance and emittance is produced by roughening the surface of the substrate, immersing the substrate in a first electroless plating bath having a low phosphorus to nickel concentration, then immersing the substrate in a second electroless plating bath having a phosphorus to nickel concentration higher than that of said first electroless plating bath. Thereafter, the resulting electroless nickel-phosphorus alloy coated substrate is immersed in an aqueous acidic etchant bath containing sulfuric acid, nitric acid and divalent nickel to develop a highly blackened surface on said substrate.

  7. Selecting the process arrangement for preparing the gas turbine working fluid for an integrated gasification combined-cycle power plant

    NASA Astrophysics Data System (ADS)

    Ryzhkov, A. F.; Gordeev, S. I.; Bogatova, T. F.

    2015-11-01

    Introduction of a combined-cycle technology based on fuel gasification integrated in the process cycle (commonly known as integrated gasification combined cycle technology) is among avenues of development activities aimed at achieving more efficient operation of coal-fired power units at thermal power plants. The introduction of this technology is presently facing the following difficulties: IGCC installations are characterized by high capital intensity, low energy efficiency, and insufficient reliability and availability indicators. It was revealed from an analysis of literature sources that these drawbacks are typical for the gas turbine working fluid preparation system, the main component of which is a gasification plant. Different methods for improving the gasification plant chemical efficiency were compared, including blast air high-temperature heating, use of industrial oxygen, and a combination of these two methods implying limited use of oxygen and moderate heating of blast air. Calculated investigations aimed at estimating the influence of methods for achieving more efficient air gasification are carried out taking as an example the gasifier produced by the Mitsubishi Heavy Industries (MHI) with a thermal capacity of 500 MW. The investigation procedure was verified against the known experimental data. Modes have been determined in which the use of high-temperature heating of blast air for gasification and cycle air upstream of the gas turbine combustion chamber makes it possible to increase the working fluid preparation system efficiency to a level exceeding the efficiency of the oxygen process performed according to the Shell technology. For the gasification plant's configuration and the GTU working fluid preparation system be selected on a well-grounded basis, this work should be supplemented with technical-economic calculations.

  8. Energy Absorption Behaviors of Nanoporous Systems

    DTIC Science & Technology

    2005-01-01

    energy absorption isotherms : (a) the first loading-unloading cycle; (b) the second, the third, and the fourth loading-unloading cycles without thermal...change, AV (cm- /g) Fig.7 The energy absorption isotherms under a cyclic loading in a 23. lwt% aqueous solution of NaC1. 80

  9. System and process for producing fuel with a methane thermochemical cycle

    SciTech Connect

    Diver, Richard B.

    2015-12-15

    A thermochemical process and system for producing fuel are provided. The thermochemical process includes reducing an oxygenated-hydrocarbon to form an alkane and using the alkane in a reforming reaction as a reducing agent for water, a reducing agent for carbon dioxide, or a combination thereof. Another thermochemical process includes reducing a metal oxide to form a reduced metal oxide, reducing an oxygenated-hydrocarbon with the reduced metal oxide to form an alkane, and using the alkane in a reforming reaction as a reducing agent for water, a reducing agent for carbon dioxide, or a combination thereof. The system includes a reformer configured to perform a thermochemical process.

  10. MTCI/ThermoChem steam reforming process for solid fuels for combined cycle power generation

    SciTech Connect

    Mansour, M.N.; Voelker, G.; Dural-Swamy, K.

    1995-12-31

    Manufacturing and Technology Conversion International, Inc. (MTCI) has developed a novel technology to convert solid fuels including biomass, coal, municipal solid waste (MSW) and wastewater sludges into usable syngas by steam reforming in an indirectly heated, fluid-bed reactor. MTCI has licensed and patented the technology to ThermoChem, Inc. Both MTCI and ThermoChem have built two modular commercial-scale demonstration units: one for recycle paper mill rejects (similar to refuse-derived fuel [RDF]), and another for chemical recovery of black liquor. ThermoChem has entered into an agreement with Ajinkyatara Cooperative Sugar Factory, India, for building a 10 MW combined cycle power generation facility based on bagasse and agro-residue gasification.

  11. Design of a Multisensory Probe for Measuring Carbon Cycle Processes in Aqueous Subterranean Environments

    SciTech Connect

    McIntyre, Timothy J; Kisner, Roger; Woodworth, Ken; Lenarduzzi, Roberto; Frank, Steven Shane; McKnight, Timothy E

    2015-01-01

    The global carbon cycle describes the exchange of carbon between the atmosphere, terrestrial vegetation, oceans, and soil. Mechanisms involving carbon in sub-terrestrial ecosystems and their impact on climate are not well understood. This lack of understanding limits current climate models and prevents accurate soil-carbon storage predications for future climate conditions. To address the lack of instrumentation for conducting high fidelity measurements of appropriate parameters in the field, a multi-sensory probe using a mix of optical, fiber optic, and electronic technologies to measure CO2, temperature, dissolved oxygen, redox potential, and water level in subsurface environments has been developed. Details of the design, fabrication and laboratory performance verification are presented. Use cases and the anticipated impacts of such measurements on climate models are discussed.

  12. Organic-Rankine-cycle systems for waste-heat recovery in refineries and chemical process plants

    SciTech Connect

    Meacher, J.S.

    1981-09-01

    The use of organic Rankine cycles (ORC) for the recovery and conversion of low-temperature waste heat has received considerable attention during recent years. The number of demonstration systems developed and put into service is small, and only a fraction of the possible energy-conserving benefits of the concept have been realized to date. This situation is due partly to the fact that energy costs have only recently risen to the point where such units provide acceptable return on investment. A second contributing factor may be that the design of ORC equipment has not yet responded to the special needs of the dominant market for ORC systems. 2 references, 12 figures, 5 tables.

  13. Impact of subgrid-scale processes on eyewall replacement cycle of tropical cyclones in HWRF system

    NASA Astrophysics Data System (ADS)

    Zhu, Ping; Zhu, Zhenduo; Gopalakrishnan, Sundararaman; Black, Robert; Marks, Frank D.; Tallapragada, Vijay; Zhang, Jun A.; Zhang, Xuejin; Gao, Cen

    2015-11-01

    Two idealized simulations by the Hurricane Weather Research and Forecast (HWRF) model are presented to examine the impact of model physics on the simulated eyewall replacement cycle (ERC). While no ERC is produced in the control simulation that uses the operational HWRF physics, the sensitivity experiment with different model physics generates an ERC that possesses key features of observed ERCs in real tropical cyclones. Likely reasons for the control simulation not producing ERC include lack of outer rainband convection at the far radii from the eyewall, excessive ice hydrometeors in the eyewall, and enhanced moat shallow convection, which all tend to prevent the formation of a persistent moat between the eyewall and outer rainband. Less evaporative cooling from precipitation in the outer rainband region in the control simulation produces a more stable and dryer environment that inhibits the development of systematic convection at the far radii from the eyewall.

  14. Development of a Safeguards Process Simulation for Open and Closed Nuclear Fuel Cycles

    NASA Astrophysics Data System (ADS)

    Shugart, Nicolas

    SafeGuards Analysis (SGA) is a computational toolbox able to simulate different safeguards scenarios across a number of different fuel cycles and at many different scales within a Matlab Simulink framework. SGA functions by simulating Material Balance Areas (MBAs) under safeguards materials control and accountability and allows the user to define the uncertainty parameters of the associated flow and inventory measurements. The simulated safeguard system uses the uncertain measurement estimates to calculate mass-balance across the MBA. This mass balance is then evaluated by one or more of a number of different statistical tests to determine if a significant amount of material has been removed from the MBA. This thesis describes the development of SGA, and presents a number of example scenarios consisting of one or more MBAs. The goal of each of these scenarios is to determine the ability of SGA to calculate the Type I (false detect) or Type II (missed detection) error probability of the scenario. In each of these example scenarios, SGA generated reasonable results. To fully demonstrate SGA's capabilities, the thesis also examines a more complicated scenario representative of a closed fuel cycle. This examination is paired with the operations research NUclear Measurement System Optimization (NUMSO) toolbox which calculates the best configuration of measurements based on a user-defined set of objectives. The two toolboxes allow a user to develop quickly develop a potentially optimal safeguards system with NUMSO, and then use SGA to examine the detailed behavior of that system. In every example considered in the thesis, SGA performs as designed.

  15. Recovery of microbial communities and carbon cycling processes following drought manipulation in southern California

    NASA Astrophysics Data System (ADS)

    Allison, S. D.; Martiny, J. B. H.; Martiny, A.; Berlemont, R.; Treseder, K. K.; Goulden, M.; Brodie, E.

    2016-12-01

    Predicting the functioning of microbial communities under changing environmental conditions remains a key challenge in Earth system science. Metagenomics and other high-throughput molecular approaches can help address this challenge by revealing the functional potential of microbial communities. We coupled metagenomics with models and experimental manipulations to address microbial responses to drought in a California grassland ecosystem along with the consequences for carbon cycling. We developed an approach for extracting trait information from metagenomic data and asked: 1) What is the phylogenetic structure of drought response traits? 2) What is the relationship between these traits and those involved in carbohydrate degradation? 3) How do both classes of traits vary seasonally and with precipitation manipulation? 4) How resilient are these traits in the face of perturbation? We found that drought response traits are phylogenetically conserved at an equivalent of 5-8% ribosomal RNA gene sequence dissimilarity. Experimental drought treatment selected for the genetic potential to degrade starch, xylan, and mixed polysaccharides, suggesting a link between drought response and carbon cycling traits. In addition, microbial communities exposed to experimental drought showed a reduced potential to degrade plant biomass. Particularly among bacteria, seasonal drought had a larger impact on microbial composition, abundance, and carbohydrate-degrading genes compared to experimental drought. Bacterial communities were also more resilient to drought perturbation than fungal communities, which showed legacies of drought perturbation for up to three years. Altogether, these findings imply that microbial communities exhibit trait diversity that facilitates resilience but with substantial time lags and consequences for carbon turnover. This information is being used to inform new trait-based models that address the challenge of predicting microbial functioning under

  16. Evolution of a detailed physiological model to simulate the gastrointestinal transit and absorption process in humans, part II: extension to describe performance of solid dosage forms.

    PubMed

    Thelen, Kirstin; Coboeken, Katrin; Willmann, Stefan; Dressman, Jennifer B; Lippert, Jörg

    2012-03-01

    The physiological absorption model presented in part I of this work is now extended to account for dosage-form-dependent gastrointestinal (GI) transit as well as disintegration and dissolution processes of various immediate-release and modified-release dosage forms. Empirical functions of the Weibull type were fitted to experimental in vitro dissolution profiles of solid dosage forms for eight test compounds (aciclovir, caffeine, cimetidine, diclofenac, furosemide, paracetamol, phenobarbital, and theophylline). The Weibull functions were then implemented into the model to predict mean plasma concentration-time profiles of the various dosage forms. On the basis of these dissolution functions, pharmacokinetics (PK) of six model drugs was predicted well. In the case of diclofenac, deviations between predicted and observed plasma concentrations were attributable to the large variability in gastric emptying time of the enteric-coated tablets. Likewise, oral PK of furosemide was found to be predominantly governed by the gastric emptying patterns. It is concluded that the revised model for GI transit and absorption was successfully integrated with dissolution functions of the Weibull type, enabling prediction of in vivo PK profiles from in vitro dissolution data. It facilitates a comparative analysis of the parameters contributing to oral drug absorption and is thus a powerful tool for formulation design. Copyright © 2011 Wiley Periodicals, Inc.

  17. The Exchange of Soil Nitrite and Atmospheric HONO: a Missing Process in the Nitrogen Cycle and Atmospheric Chemistry

    NASA Astrophysics Data System (ADS)

    Cheng, Yafang; Su, Hang; Oswald, Robert; Behrendt, Thomas; Trebs, Ivonne; Meixner, Franz X.; Andreae, Meinrat O.; Pöschl, Ulrich

    2013-04-01

    Hydroxyl radicals (OH) are a key species in atmospheric photochemistry. In the lower atmosphere, up to ~30% of the primary OH radical production is attributed to the photolysis of nitrous acid (HONO), and field observations suggest a large missing source of HONO. The dominant sources of N(III) in soil, however, are biological nitrification and denitrification processes, which produce nitrite ions from ammonium (by nitrifying microbes) as well as from nitrate (by denitrifying microbes). We show that soil nitrite can release HONO and explain the reported strength and diurnal variation of the missing source. We also show that the soil-atmosphere exchange of N(III), though not considered in the N cycle, might result in significant amount of reactive nitrogen emission (comparable to soil NO emissions). Fertilized soils with low pH appear to be particularly strong sources of HONO and OH. Thus, agricultural activities and land-use changes may strongly influence the oxidizing capacity of the atmosphere. Because of the widespread occurrence of nitrite-producing microbes and increasing N and acid deposition, the release of HONO from soil may also be important in natural environments, including forests and boreal regions. In view of the potentially large impact on atmospheric chemistry and global environmental change, we recommend further studies of HONO release from soil nitrite and related processes in the biogeochemical cycling of N in both agricultural and natural environments. Reference: Su, H., Cheng, Y., et al., Soil Nitrite as a Source of Atmospheric HONO and OH Radicals, Science, 333, 1616-1618, 10.1126/science.1207687, 2011. Su, H., et al., The Exchange of Soil Nitrite and Atmospheric HONO: A Missing Process in the Nitrogen Cycle and Atmospheric Chemistry, NATO Science for Peace and Security Series C: Environmental Security, Springer Netherlands, 93-99, 2013.

  18. Process and apparatus for compression release engine retarding producing two compression release events per cylinder per engine cycle

    SciTech Connect

    Sickler, K.H.

    1986-02-25

    A process is described for compression release retarding of a cycling multi-cylinder four cycle internal combustion engine having a crankshaft and an engine piston operatively connected to the crankshaft for each cylinder thereof and having intake and exhaust valves for each cylinder thereof. An engine retarding system of a gas compression release type is also described comprising a multi-cylinder four cycle internal combustion engine having a crankshaft and a camshaft driven in synchronism with the crankshaft, engine piston means associated with the crankshaft, exhaust valve means and intake valve means associated with each cylinder of the engine. It also includes first and second pushtube means driven from the camshaft, hydraulic fluid supply means, hydraulically actuated first piston means associated with the exhaust valve means to open the exhaust valve means. Second piston means are actuated by the first pushtube means and hydraulically interconnected with the first piston means and the hydraulic fluid supply means to open the exhaust valve means during an upstroke of the engine piston associated with the exhaust valve means corresponding to its compression stroke during normal operation of the engine to produce a first compression release event.

  19. Incorporating Ecosystem Experiments and Observations into Process Models of Forest Carbon and Water Cycles: Challenges and Solutions

    NASA Astrophysics Data System (ADS)

    Ward, E. J.; Thomas, R. Q.; Sun, G.; McNulty, S. G.; Domec, J. C.; Noormets, A.; King, J. S.

    2015-12-01

    Numerous studies, both experimental and observational, have been conducted over the past two decades in an attempt to understand how water and carbon cycling in terrestrial ecosystems may respond to changes in climatic conditions. These studies have produced a wealth of detailed data on key processes driving these cycles. In parallel, sophisticated models of these processes have been formulated to answer a variety of questions relevant to natural resource management. Recent advances in data assimilation techniques offer exciting new possibilities to combine this wealth of ecosystem data with process models of ecosystem function to improve prediction and quantify associated uncertainty. Using forests of the southeastern United States as our focus, we will specify how fine-scale physiological (e.g. half-hourly sap flux) can be scaled up with quantified error for use in models of stand growth and hydrology. This approach represents an opportunity to leverage current and past research from experiments including throughfall displacement × fertilization (PINEMAP), irrigation × fertilization (SETRES), elevated CO­2­ (Duke and ORNL FACE) and a variety of observational studies in both conifer and hardwood forests throughout the region, using a common platform for data assimilation and prediction. As part of this discussion, we will address variation in dominant species, stand structure, site age, management practices, soils and climate that represent both challenges to the development of a common analytical approach and opportunities to address questions of interest to policy makers and natural resource managers.

  20. Energy balance of the closed oxygen cycle and processes causing thermal runaway in valve-regulated lead/acid batteries

    NASA Astrophysics Data System (ADS)

    Pavlov, D.

    A model for the reactions involved in the closed oxygen cycle in valve-regulated lead/acid batteries and the associated energy transformations is proposed. When electric current flows through the closed oxygen cycle, a certain amount of electric energy is converted via electrochemical processes into chemical energy, i.e. the products obtained may interact spontaneously as a result of which the system returns to its initial state. During these spontaneous reactions, the chemical energy is converted into heat. Depending on the type of the reactions involved in oxygen reduction on the negative plate, the closed oxygen cycle may proceed in two different electrochemical systems: (i) oxygen is reduced through electrochemical reactions yielding the electrochemical system PbO 2//H 2OO/O 2///O 2//H 2OO/Pb, and (ii) oxygen is reduced through chemical reactions forming the electrochemical system PbO 2//H 2OO/O 2///PbSO 4//Pb. The energy introduced into the system for activation of the closed oxygen cycle is different for the two electrochemical systems. The quantity of this energy is calculated in the present work using thermodynamic data. During the closed oxygen cycle the electric energy is transformed into chemical energy which, in turn, is converted into heat. Part of this heat causes the cell temperature to increase and another part dissipates into the surrounding air. The amount of the former heat depends on the heat capacity of the battery and is influenced most strongly by the quantity of the electrolyte. It has been established that the rate of oxygen evolution on the positive plate depends strongly on the temperature. When the heat exchange between the battery and the surrounding medium is poor, the reactions of the closed oxygen cycle may enter (through the heat and oxygen flows between the positive and the negative plates) into self-accelerating interrelations, which may lead to thermal runaway. To avoid this, an adequate heat exchange should be maintained between

  1. Parameter identifiability and Extended Multiple Studies Analysis of a compartmental model for human vitamin A kinetics: fixing fractional transfer coefficients for the initial steps in the absorptive process.

    PubMed

    Park, Hyunjin; Green, Michael H

    2014-03-28

    In the existing compartmental models of human vitamin A metabolism, parameters related to the absorption of the isotopic oral dose have not been well identified. We hypothesised that fixing some poorly identified parameters related to vitamin A absorption would improve parameter identifiability and add statistical certainty to such models. In the present study, data for serum vitamin A kinetics in nine subjects given [2H8]retinyl acetate orally and a model with absorption fixed at 75 % were used to test this hypothesis. In addition to absorption efficiency, we fixed two other fractional transfer coefficients: one representing the initial processing of the ingested dose and the other representing the direct secretion of retinol bound to retinol-binding protein (RBP) from enterocytes into the plasma. The Windows version of Simulation, Analysis and Modeling software (WinSAAM) was used to fit serum tracer data v. time for each subject. Then, a population model was generated by WinSAAM's Extended Multiple Studies Analysis. All the parameters had fractional standard deviations < 0·5, and none of the pairs of parameters had a correlation coefficient >0·8 (accepted criteria for well-identified parameters). Similar to the values predicted by the original model, total traced mass for retinol was 1160 (sd 468) μmol, and the time for retinol to appear in the plasma bound to RBP was 31·3 (sd 4·4) h. In conclusion, we suggest that this approach holds promise for advancing compartmental modelling of vitamin A kinetics in humans when the dose must be administered orally.

  2. Carbon cycle. Sunlight controls water column processing of carbon in arctic fresh waters.

    PubMed

    Cory, Rose M; Ward, Collin P; Crump, Byron C; Kling, George W

    2014-08-22

    Carbon in thawing permafrost soils may have global impacts on climate change; however, the factors that control its processing and fate are poorly understood. The dominant fate of dissolved organic carbon (DOC) released from soils to inland waters is either complete oxidation to CO2 or partial oxidation and river export to oceans. Although both processes are most often attributed to bacterial respiration, we found that photochemical oxidation exceeds rates of respiration and accounts for 70 to 95% of total DOC processed in the water column of arctic lakes and rivers. At the basin scale, photochemical processing of DOC is about one-third of the total CO2 released from surface waters and is thus an important component of the arctic carbon budget.

  3. Biotic and abiotic controls on co-occurring nitrogen cycling processes in shallow Arctic shelf sediments

    NASA Astrophysics Data System (ADS)

    McTigue, N. D.; Gardner, W. S.; Dunton, K. H.; Hardison, A. K.

    2016-10-01

    The processes that convert bioavailable inorganic nitrogen to inert nitrogen gas are prominent in continental shelf sediments and represent a critical global sink, yet little is known of these pathways in the Arctic where 18% of the world's continental shelves are located. Moreover, few data from the Arctic exist that separate loss processes like denitrification and anaerobic ammonium oxidation (anammox) from recycling pathways like dissimilatory nitrate reduction to ammonium (DNRA) or source pathways like nitrogen fixation. Here we present measurements of these co-occurring processes using 15N tracers. Denitrification was heterogeneous among stations and an order of magnitude greater than anammox and DNRA, while nitrogen fixation was undetectable. No abiotic factors correlated with interstation variability in biogeochemical rates; however, bioturbation potential explained most of the variation. Fauna-enhanced denitrification is a potentially important but overlooked process on Arctic shelves and highlights the role of the Arctic as a significant global nitrogen sink.

  4. Biotic and abiotic controls on co-occurring nitrogen cycling processes in shallow Arctic shelf sediments

    PubMed Central

    McTigue, N. D.; Gardner, W. S.; Dunton, K. H.; Hardison, A. K.

    2016-01-01

    The processes that convert bioavailable inorganic nitrogen to inert nitrogen gas are prominent in continental shelf sediments and represent a critical global sink, yet little is known of these pathways in the Arctic where 18% of the world's continental shelves are located. Moreover, few data from the Arctic exist that separate loss processes like denitrification and anaerobic ammonium oxidation (anammox) from recycling pathways like dissimilatory nitrate reduction to ammonium (DNRA) or source pathways like nitrogen fixation. Here we present measurements of these co-occurring processes using 15N tracers. Denitrification was heterogeneous among stations and an order of magnitude greater than anammox and DNRA, while nitrogen fixation was undetectable. No abiotic factors correlated with interstation variability in biogeochemical rates; however, bioturbation potential explained most of the variation. Fauna-enhanced denitrification is a potentially important but overlooked process on Arctic shelves and highlights the role of the Arctic as a significant global nitrogen sink. PMID:27782213

  5. Realization of tellurium-based all dielectric optical metamaterials using a multi-cycle deposition-etch process

    NASA Astrophysics Data System (ADS)

    Liu, Sheng; Ihlefeld, Jon F.; Dominguez, Jason; Gonzales, Edward F.; Eric Bower, John; Bruce Burckel, D.; Sinclair, Michael B.; Brener, Igal

    2013-04-01

    Tellurium (Te) dielectric resonator metamaterials for thermal infrared applications were fabricated using a multi-cycle deposition-etch process that circumvents pinch-off issues during deposition. Deposition and etching of Te were studied in detail. Metamaterial samples with varying resonator dimensions were fabricated using this technique. All the samples showed two transmission minima corresponding to magnetic and electric dipole resonances. Longer resonant wavelengths were observed as the resonator dimension was increased. Observation of spectral overlap between magnetic and electric resonances gives us the potential opportunity to realize a negative refractive index material.

  6. The effect of pathological processes on absorption and scattering spectra of samples of bile and pancreatic juice

    NASA Astrophysics Data System (ADS)

    Giraev, K. M.; Ashurbekov, N. A.; Magomedov, M. A.; Murtazaeva, A. A.; Medzhidov, R. T.

    2015-07-01

    Spectra of optical transmission coefficients and optical reflectance for bile and pancreatic juice samples were measured experimentally for different forms of pathologies of the pancreas within the range of 250-2500 nm. The absorption and scattering spectra, as well as the spectrum of the anisotropy factor of scattering, were determined based on the results obtained using the reverse Monte Carlo method. The surface morphology for the corresponding samples of the biological media was studied employing electron microscopy. The dynamics of the optical properties of the biological media was determined depending on the stage of the pathology. It has been demonstrated that the results of the study presented are in a good agreement with pathophysiological data and could supplement and broaden the results of conventional methods for diagnostics of the pancreas.

  7. GRBs Radiative Processes: Synchrotron and Synchrotron Self-Absorption From a Power Law Electrons Distribution with Finite Energy Range

    NASA Astrophysics Data System (ADS)

    Fouka, M.; Ouichaoui, S.

    2010-10-01

    Synchrotron emission behind relativistic magnetic internal-external shocks in gamma-ray bursts cosmological explosions is assumed to be the basic emission mechanism for prompt and afterglow emissions. Inverse Compton from relativistic electrons can also have appreciable effects by upscattering initial synchrotron or blackbody photons or other photons fields up to GeV-TeV energies. For extreme physical conditions such as high magnetic fields (e.g., B>105 Gauss) self-absorption is not negligible and can hardly affect spectra at least for the low energy range. In this paper we present calculations of the synchrotron power, Pν, and their asymptotic forms, generated by a power law relativistic electron distribution of type Ne(γ) = Cγ-p with γ1<γ<γ2, especially for finite values of the higher limit γ2. For this aim we defined the dimensionless parametric function Zp(x,ɛ) with x = ν/ν1 and ɛ = γ2/γ1 so that Pν~Zp(ν/ν1,ɛ), with ν1 = (3/4π)γ12qBsinθ/mc (θ being the pitch angle). Asymptotic forms of this later are derived for three different frequency ranges, i.e., x<<1, 1<>ɛ2. These results are then used to calculate the absorption coefficient, αν, and the source function, Sν, together with their asymptotic forms through the dimensionless parametric functions Hp(x,ɛ) and Yp(x,ɛ), respectively. Further calculation details are also presented and discussed.

  8. Quantification of rapid environmental redox processes with quick-scanning x-ray absorption spectroscopy (Q-XAS).

    PubMed

    Ginder-Vogel, Matthew; Landrot, Gautier; Fischel, Jason S; Sparks, Donald L

    2009-09-22

    Quantification of the initial rates of environmental reactions at the mineral/water interface is a fundamental prerequisite to determining reaction mechanisms and contaminant transport modeling and predicting environmental risk. Until recently, experimental techniques with adequate time resolution and elemental sensitivity to measure initial rates of the wide variety of environmental reactions were quite limited. Techniques such as electron paramagnetic resonance and Fourier transform infrared spectroscopies suffer from limited elemental specificity and poor sensitivity to inorganic elements, respectively. Ex situ analysis of batch and stirred-flow systems provides high elemental sensitivity; however, their time resolution is inadequate to characterize rapid environmental reactions. Here we apply quick-scanning x-ray absorption spectroscopy (Q-XAS), at sub-second time-scales, to measure the initial oxidation rate of As(III) to As(V) by hydrous manganese(IV) oxide. Using Q-XAS, As(III) and As(V) concentrations were determined every 0.98 s in batch reactions. The initial apparent As(III) depletion rate constants (t < 30 s) measured with Q-XAS are nearly twice as large as rate constants measured with traditional analytical techniques. Our results demonstrate the importance of developing analytical techniques capable of analyzing environmental reactions on the same time scale as they occur. Given the high sensitivity, elemental specificity, and time resolution of Q-XAS, it has many potential applications. They could include measuring not only redox reactions but also dissolution/precipitation reactions, such as the formation and/or reductive dissolution of Fe(III) (hydr)oxides, solid-phase transformations (i.e., formation of layered-double hydroxide minerals), or almost any other reaction occurring in aqueous media that can be measured using x-ray absorption spectroscopy.

  9. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  10. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  11. Probing the Baryon Cycle in Galaxy Outskirts

    NASA Astrophysics Data System (ADS)

    Davé, Romeel

    2017-03-01

    Galaxies are born and grow within a cosmic ecosystem, in which they receive material from surrounding intergalactic gas via gravitationally-driven inflows and expel material via powerful galactic outflows. These processes, collectively referred to as the baryon cycle, are increasingly believed to govern galaxy growth over cosmic time. I discuss new insights on the baryon cycle using analytic models and hydrodynamical simulations of galaxy evolution, particularly emphasizing how galaxy outskirts are the prime locale within which to observe these processes in action by examining observational tracers such as rest-ultraviolet absorption lines and the neutral and molecular gas content of galaxies.

  12. Life cycle assessment of cheese production process in a small-sized dairy industry in Brazil.

    PubMed

    Santos, Hudson Carlos Maia; Maranduba, Henrique Leonardo; de Almeida Neto, José Adolfo; Rodrigues, Luciano Brito

    2017-02-01

    Current research identifies, analyzes, and suggests improvements for minimizing environmental impacts in the manufacture of cheese using the life cycle assessment. Data collection and development of the inventory were performed in a small-sized dairy industry in Brazil. A cradle-to-gate approach was conducted based on the primary data from cheese production and secondary data from databases. The ReCiPe method was used for the impact assessment, considering the categories climate change, ozone depletion, terrestrial acidification, freshwater eutrophication, photochemical oxidant formation, particulate matter formation, water depletion, and fossil depletion. A sensitivity analysis was performed including evaluations of different fuels for generating thermal energy, strategies for cleaning of dairy plant and utensils, variations in the way of cheese production based on the fat content, and production percentage changes. The results showed that the skimmed milk and thermal energy productions, electricity usage, and water consumptions were the main elementary flows. The pallet residues showed the best to be used as fuel for thermal energy. Detergent combinations did not influence the impact categories. There was a direct relationship between fat content range (20 to 30%) and the contribution in six impact categories. Changes from 20% in cheese allocation factor influenced the impact assessment results. LCA allowed identifying the main elementary flow of cheese production, providing valuable information with the potential to verify opportunities for on-site improvements.

  13. Perspectives on Applying Metabolomics to Understand Carbon Cycling and Process Rates in Deep-Sea Microorganisms

    NASA Astrophysics Data System (ADS)

    Vidoudez, C.; Saghatelian, A.; Girguis, P. R.

    2014-12-01

    The metabolisms of deep-sea microorganisms are still poorly characterized. So far, transcriptomics has been the most comprehensive proxy for the whole metabolisms of these organisms, but this approach is limited because it only represents the physiological poise of the cells, and is not linearly correlated to the rates and activity of the metabolic pathways. Using thermodynamics calculations and isotopic analyses can provide constraints on activity, but there are often discrepancies between available energy and calculated active biomass. A further understanding of metabolism both at the species and community level is necessary and metabolomics provides a means of capturing a "snapshot" of cell's metabolite pools, or of following labelled substrates as they move through metabolic pathways. We present our method development and initial results from our studies of the model organism Photobacterium profundum, and the benefits and challenges in meaningfully applying these methods to natural communities. These methods open the way to better understanding deep-sea metabolism on a more comprehensive level, including reserves compounds, alternate and secondary metabolism and potentially new metabolic pathways, and moreover the response of metabolism to changes in experimental conditions and carbon source can be readily followed. These will allow a better understanding of the carbon cycling pathways and their rate in natural communities.

  14. Cell cycle and immune-related processes are significantly altered in chronic GVHD.

    PubMed

    Oh, S J; Cho, S B; Park, S-H; Piao, C Z; Kwon, S M; Kim, I; Yoon, S S; Kim, B K; Park, E K; Kang, J J; Yang, S-J; Lee, W J; Yoo, C-H; Hwang, S; Kim, S H; Kim, J H; Park, S

    2008-06-01

    Currently, the pathogenesis of chronic GVHD is unclear. To elucidate the molecular characteristics underlying chronic GVHD, we analyzed the gene expression profiles of 21 mononuclear cell samples from allogeneic hematopoietic stem cell transplantation (HSCT) recipients. Self organizing map (SOM) clustering showed that the entire expression profiles of chronic GVHD samples were clearly different from those of the non-GVHD samples, and significance analysis of microarray (SAM) demonstrated that 120 genes, including PTDSS1, VAV1 and CD3D, were up-regulated, and 5 genes, including calnexin, were down-regulated in GVHD patients. Gene ontology annotation revealed that these genes are related to the phosphorous metabolism and lipid biosynthesis. Quantitative real time polymerase chain reaction (qRT-PCR) experiments validated the up-regulation of PTDSS1, VAV1 and CD3D in separate samples. Pathway-wise global test revealed that differential gene expression in cell cycle and T cell immune-associated pathways were significant between GVHD patients and non-GVHD patients. Seventeen classifier genes selected using a PAM (prediction analysis of microarray) algorithm showed favorable performance (prediction accuracy=0.85) for identifying patients with chronic GVHD. In conclusion, we identified differentially expressed genes and pathways in chronic GVHD patients using microarray analysis, and we also selected diagnostic genes predicting chronic GVHD status.

  15. Life cycle assessment of flexibly fed biogas processes for an improved demand-oriented biogas supply.

    PubMed

    Ertem, Funda Cansu; Martínez-Blanco, Julia; Finkbeiner, Matthias; Neubauer, Peter; Junne, Stefan

    2016-11-01

    This paper analyses concepts to facilitate a demand oriented biogas supply at an agricultural biogas plant of a capacity of 500kWhel, operated with the co-digestion of maize, grass, rye silage and chicken manure. In contrast to previous studies, environmental impacts of flexible and the traditional baseload operation are compared. Life Cycle Assessment (LCA) was performed to detect the environmental impacts of: (i) variety of feedstock co-digestion scenarios by substitution of maize and (ii) loading rate scenarios with a focus on flexible feedstock utilization. Demand-driven biogas production is critical for an overall balanced power supply to the electrical grid. It results in lower amounts of emissions; feedstock loading rate scenarios resulted in 48%, 20%, 11% lower global warming (GWP), acidification (AP) and eutrophication potentials, and a 16% higher cumulative energy demand. Substitution of maize with biogenic-waste regarding to feedstock substitution scenarios could create 10% lower GWP and AP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Life-cycle assessment of a waste refinery process for enzymatic treatment of municipal solid waste.

    PubMed

    Tonini, D; Astrup, T

    2012-01-01

    Decrease of fossil fuel dependence and resource saving has become increasingly important in recent years. From this perspective, higher recycling rates for valuable materials (e.g. metals) as well as energy recovery from waste streams could play a significant role substituting for virgin material production and saving fossil resources. This is especially important with respect to residual waste (i.e. the remains after source-separation and separate collection) which in Denmark is typically incinerated. In this paper, a life-cycle assessment and energy balance of a pilot-scale waste refinery for the enzymatic treatment of municipal solid waste (MSW) is presented. The refinery produced a liquid (liquefied organic materials and paper) and a solid fraction (non-degradable materials) from the initial waste. A number of scenarios for the energy utilization of the two outputs were assessed. Co-combustion in existing power plants and utilization of the liquid fraction for biogas production were concluded to be the most favourable options with respect to their environmental impacts (particularly global warming) and energy performance. The optimization of the energy and environmental performance of the waste refinery was mainly associated with the opportunity to decrease energy and enzyme consumption. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. The Primary and Secondary Production of Germanium: A Life-Cycle Assessment of Different Process Alternatives

    NASA Ast