Spectrochemical analysis of aluminum and its alloys, and S. A. P

International Nuclear Information System (INIS)

Roca, M.

1966-01-01

Three different techniques have been employed for the spectrochemical analysis of aluminum, aluminum alloys, and S.A.P. :1) Point to plane with condensed spark and direct reading spectrometry; from the study on the instantaneous spectral-line intensities a long pre integration time has been established. 1) Powdered samples technique with direct current arc and also direct reading spectrometry; samples are transformed into Al 2 O 3 and mixed with graphite powder (1:1). A complete study on the different elements in aluminium oxide, aluminium sulfate and their mixtures with graphite, has been carried out. 3) Carrier distillation method with photographic recording for very low concentrations of boron and cadmium in S. A.P. (Author) 10 refs

Direct reading spectrochemical determination of aluminium, iron and silicon in fluorite

International Nuclear Information System (INIS)

Roca, M.

1966-01-01

A quantitative spectrochemical method for the determination of Al, Fe and Si in fluorite has been worked out. The sample was supported in a graphite electrode with crater of 5 mm. in diameter, 2,5 mm deep, and burned by a d.c. are in a direct reading spectrometer. The excitation of samples has been studied without dilution as well as using graphite powder as diluent in the ratios 1:1, 1:4, and 1:9; the latter factor was chosen. Ag, Ca, Co, Cr, Mo and Sn were tested as internal standards. It has not been found any significant inter element effect. It is necessary to use natural fluorite as base material for the standards. (Author) 5 refs

Spectrochemical investigation of neodymium fluorinated #betta#-diketonates

International Nuclear Information System (INIS)

Khomenko, V.S.; Rasshinina, T.A.; Lozinskij, M.O.; Fialkov, Yu.A.

1982-01-01

A spectrochemical study is carried out on neodymium complexes with #betta#-diketonates of the following contents: Nd(tdh) 4 xHP, Nd(tdh) 3 xbipy, Nd(tdh) 3 xC 10 D 8 N 2 , Nd(tdh) 3 xphen, Nd(fod) 4 xHP, Nd(fod) 3 xbipy, Nd(fod) 3 xphen, where tdh - 1, 1, 1,-trifluoro-5, 5 dimethylhexanedione-2, 4; fod - 1, 1, 1, 2, 2, 3, 3-heptafluoro-7, 7-dimethyloctanedione-4, 6; bipy - 2, 2'-dipyridyl- phen - 1, 10-phenanthroline; p - piperidine; C 10 D 8 N 2 - deuterated 2, 2'-dipyridyl. A change in the metal-ligand bond character was determined by means of the nepheloxetic effect (band shift in absorption spectra at the expense of an interelectron repulsion decrease in the 4f-electron shell due to its expansion during the formation of partially covalent metal-ligand bonds). Mutual ligand effect on the complex properties was also studied using the mass spectrometric method. It is established that an extra addition of a bisheterocycle to a triligand rare-earth complex makes an average bond in a complex more covalent

Spectrochemical investigation of neodymium fluorinated. beta. -diketonates

Energy Technology Data Exchange (ETDEWEB)

Khomenko, V.S.; Rasshinina, T.A.; Lozinskij, M.O.; Fialkov, Yu.A.

1982-10-01

A spectrochemical study is carried out on neodymium complexes with ..beta..-diketonates of the following contents: Nd(tdh)/sub 4/xHP, Nd(tdh)/sub 3/xbipy, Nd(tdh)/sub 3/xC/sub 10/D/sub 8/N/sub 2/, Nd(tdh)/sub 3/xphen, Nd(fod)/sub 4/xHP, Nd(fod)/sub 3/xbipy, Nd(fod)/sub 3/xphen, where tdh - 1, 1, 1,-trifluoro-5, 5 dimethylhexanedione-2, 4; fod - 1, 1, 1, 2, 2, 3, 3-heptafluoro-7, 7-dimethyloctanedione-4, 6; bipy - 2, 2'-dipyridyl- phen - 1, 10-phenanthroline; p - piperidine; C/sub 10/D/sub 8/N/sub 2/ - deuterated 2, 2'-dipyridyl. A change in the metal-ligand bond character was determined by means of the nepheloxetic effect (band shift in absorption spectra at the expense of an interelectron repulsion decrease in the 4f-electron shell due to its expansion during the formation of partially covalent metal-ligand bonds). Mutual ligand effect on the complex properties was also studied using the mass spectrometric method. It is established that an extra addition of a bisheterocycle to a triligand rare-earth complex makes an average bond in a complex more covalent.

Buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions: from protein buffer capacity prediction to bioprocess applications.

Science.gov (United States)

Bahrenburg, Sven; Karow, Anne R; Garidel, Patrick

2015-04-01

Protein therapeutics, including monoclonal antibodies (mAbs), have significant buffering capacity, particularly at concentrations>50 mg/mL. This report addresses pH-related issues critical to adoption of self-buffered monoclonal antibody formulations. We evaluated solution conditions with protein concentrations ranging from 50 to 250 mg/mL. Samples were both buffer-free and conventionally buffered with citrate. Samples were non-isotonic or adjusted for isotonicity with NaCl or trehalose. Studies included accelerated temperature stability tests, shaking stability studies, and pH changes in infusion media as protein concentrate is added. We present averaged buffering slopes of capacity that can be applied to any mAb and present a general method for calculating buffering capacity of buffer-free, highly concentrated antibody liquid formulations. In temperature stability tests, neither buffer-free nor conventionally buffered solution conditions showed significant pH changes. Conventionally buffered solutions showed significantly higher opalescence than buffer-free ones. In general, buffer-free solution conditions showed less aggregation than conventionally buffered solutions. Shaking stability tests showed no differences between buffer-free and conventionally buffered solutions. "In-use" preparation experiments showed that pH in infusion bag medium can rapidly approximate that of self-buffered protein concentrate as concentrate is added. In summary, the buffer capacity of proteins can be predicted and buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emission spectrochemical determination of boron in steels with pulse height distribution analyzer

International Nuclear Information System (INIS)

Ito, Minao; Sato, Shoki; Fushida, Hiroshi; Narita, Masanao

1983-01-01

The method for rapid determination of total, acid soluble and insoluble boron was established by using emission spectrochemical apparatus equipped with pulse height distribution analyzer. By using the analyzer, emission intensity can be expressed as different level intensity of pulse height distribution. It was made clear that soluble and insoluble boron had different contribution degree to each intensity and that this contribution degree varied at different pre-spark. Therefore, it is necessary for accurate determination of boron that this contribution degree should be corrected by using two intensities, of which contribution degrees are different. It was found on this two intensities method that total and soluble boron corresponded well to 50 % intensities at zero pre-spark and at 2000 pre-spark and that insoluble boron corresponded well to 70 % intensity at zero pre-spark and 50 % intensity at 2000 pre-spark. (author)

Spectrochemical Series and the Dependence of Racah and 10Dq Parameters on the Metal−Ligand Distance: Microscopic Origin

DEFF Research Database (Denmark)

Trueba, A.; Garcia-Fernandez, P.; García Lastra, Juan Maria

2011-01-01

The origin of the spectrochemical series and the different dependence of crystal-field splitting (10Dq) and Racah parameters on the metal−ligand distance, R, is explored through ab initio calculations on Cr3+-doped K2NaScF6, Cs2NaYCl6, Cs2NaYBr6, and Cs2NaYI6 lattices. For this purpose both...... is actually responsible for the reduction of Racah parameters. This study thus reveals the microscopic origin of the stronger dependence upon R of 10Dq when compared to that observed for Racah parameters, thus explaining why electronic transitions which are 10Dq-independent give rise to sharp optical bands...

The effect of ochre applied to buffer zones on soluble phosphorus retention during combined surface and subsurface flow conditions

Science.gov (United States)

Habibiandehkordi, R.; Quinton, J.; Surridge, B.

2012-12-01

Despite invention of a wide range of mitigating measures, diffuse phosphorus (P) pollution from agricultural lands still remains a major threat to the water resources. Thus, reducing P inputs along with improving the effectiveness of current best management practices (BMPs) is necessary to avoid eutrophication. Buffer zones are considered to be among the BMPs to control diffuse P pollution. However, these features are less effective in controlling soluble P loss with a retention range of -71 to +95% which is generally governed by the process of infiltration. Moreover, the soil in buffer strip system can be saturated over a course of time thereby enriching surface and subsurface runoff with soluble P. The aim of this study is to evaluate effectiveness of ochre applied to buffer strips in reducing the loss of soluble P during coupled surface and subsurface flow conditions. Batch experiments showed a maximum P retention capacity of 17.2 g kg-1 for ochre collected from a mine water treatment plant in Capehouse, UK without any risk of P desorption or releasing trace elements to the environment. The preliminarily results of flume experiments confirms the suitability of ochre to be used as a soil amendment in conjunction with buffer strips for tackling soluble P loss.

The non-easily ionized elements as spectrochemical buffers

International Nuclear Information System (INIS)

Tripkovic, M.; Radovanov, S.; Holclajtner-Antunovic, I.; Todorovic, M.

1985-01-01

A method is developed for determining trace elements (In, Ga, B, V, Mo, Mn, Pt, P, Be) in graphite with the aid of a low current d.c. arc. The method makes use of the enhancement of the radiation intensities of trace elements by non-easily ionized elements (NEIE). As a NEIE, this method uses Cd which is added up to a concentration of 150 mg/g sample. The absolute detection limits for all of the above mentioned elements are at the ng-level. (orig.) [de

Buffer capacity of biologics--from buffer salts to buffering by antibodies.

Science.gov (United States)

Karow, Anne R; Bahrenburg, Sven; Garidel, Patrick

2013-01-01

Controlling pH is essential for a variety of biopharmaceutical process steps. The chemical stability of biologics such as monoclonal antibodies is pH-dependent and slightly acidic conditions are favorable for stability in a number of cases. Since control of pH is widely provided by added buffer salts, the current study summarizes the buffer characteristics of acetate, citrate, histidine, succinate, and phosphate buffers. Experimentally derived values largely coincide with values calculated from a model that had been proposed in 1922 by van Slyke. As high concentrated protein formulations become more and more prevalent for biologics, the self-buffering potential of proteins becomes of relevance. The current study provides information on buffer characteristics for pH ranges down to 4.0 and up to 8.0 and shows that a monoclonal antibody at 50 mg/mL exhibits similar buffer capacity as 6 mM citrate or 14 mM histidine (pH 5.0-6.0). Buffer capacity of antibody solutions scales linearly with protein concentration up to more than 200 mg/mL. At a protein concentration of 220 mg/mL, the buffer capacity resembles the buffer capacity of 30 mM citrate or 50 mM histidine (pH 5.0-6.0). The buffer capacity of monoclonal antibodies is practically identical at the process relevant temperatures 5, 25, and 40°C. Changes in ionic strength of ΔI=0.15, in contrast, can alter the buffer capacity up to 35%. In conclusion, due to efficient self-buffering by antibodies in the pH range of favored chemical stability, conventional buffer excipients could be dispensable for pH stabilization of high concentrated protein solutions. Copyright © 2013 American Institute of Chemical Engineers.

Applying critical chain buffer management theory in location-based management

DEFF Research Database (Denmark)

Büchmann-Slorup, Rolf

2014-01-01

that time estimates become self-fulfilling prophecies, as practitioners tend to procrastinate, and the buffers are often wasted. In addition, excess time rarely benefits the project if activities do finish early, because succeeding activities are unlikely to begin before the planned date. Although...

Chemical and spectrochemical production analysis of ThO2 and 233UO2-ThO2 pellets for the light water breeder reactor core for Shippingport (LWBR development program)

International Nuclear Information System (INIS)

Bukowski, J.F.; Hollis, E.D.

1975-06-01

The Bettis Atomic Power Laboratory has utilized wet chemical, emission spectrochemical, and mass spectrometric analytical techniques for the production analysis of the ThO 2 and 233 UO 2 -ThO 2 (1 to 6 wt percent 233 UO 2 ) pellets for the Light Water Breeder Reactor (LWBR) core for Shippingport. Proof of the fuel breeding concept necessitates measurement of precise and accurate chemical characterization of all fuel pellets before core life. Chemistry's efforts toward this goal are presented in three main sections: (1) general discussions relating the chemical requirements for ThO 2 and 233 UO 2 -ThO 2 core materials to the analytical capabilities, (2) technical discussions of the chemical and instrumental technology applied for the analysis of aluminum, boron, calcium, carbon, chloride plus bromide, chromium, cobalt, copper, dysprosium, europium, fluoride, gadolinium, iron, magnesium, manganese, mercury, molybdenum, nickel, nitrogen, samarium, silicon, titanium, vanadium, thorium, and uranium (total, trace, and uranium VI), and (3) a formal presentation of the analytical procedures as applied to the LWBR Development Program. (U.S.)

Volatilization-excitation phenomena and efficiency of spectrochemical buffers in the analysis of geological samples. I. The action of the mixture Li2CO3: Grafite

International Nuclear Information System (INIS)

Diaz-Guerra, J.P.; Roca, M.

1984-01-01

The volatilization-excitation mechanisms of Li 2 CO 3 , SrCO 3 and GeO 2 as buffers for the determination of different major constituents in geological samples have been investigated considering the phenomena taking place in the electrode, anodic load and are plasma. The present paper deals with the evaluation of fundamental parameters and processes in d.c. are that have first been applied to the study of a Li 2 CO 3 : graphite (1:1) mixture. A second paper Is devoted to ascertain the action of each of the other two species. Intensity-time curves, variation of voltage between the electrodes, vapour diffusion through the electrode wall, load depletion, reaction products formation, and temperature, electron pressure and ionization degree in the are plasma have been studied. The measurement of plasma parameters has been performed by introducing thermometric and manometric species in both the anode and the cathode electrodes. A procedure for calculating the relative emission efficiencies of the analytical lines, taking into account the transportation process, has been developed. (Author) 21 refs

Volatilization-excitation phenomena and efficiency of spectrochemical buffers in the analysis of geological samples. I. The action of the mixture Li2CO3: graphite

International Nuclear Information System (INIS)

Diaz-Guerra, J.P.; Roca, M.

1984-01-01

The volatilization-excitation mechanisms of Li 2 CO 3 , SrCO 3 and GeO 2 as buffers for the determination of different major constituents in geological samples have been investigated considering the phenomena taking place in the electrode, anodic load and arc plasma. The present paper deals with the evaluation of fundamental parameters and processes in d.c. arc that have first been applied to the study of a Li 2 CO 3 : graphite (1:1) mixture. A second paper is devoted to ascertain the action of each of the other two species. Intensity-time curves, variation of voltage between the electrodes, vapour diffusion through the electrode wall, load depletion, reaction products formation, and temperature, electron pressure and ionization degree in the arc plasma have been studied. The measurement of plasma parameters has been performed by introducing thermometric and manometric species in both the anode and the cathode electrodes. A procedure for calculating the relative emission efficiencies of the analytical lines, taking into account the transportation process, has been developed. (author)

Buffering action of human dentin in vitro.

Science.gov (United States)

Camps, J; Pashley, D H

2000-01-01

The purpose of this study was to determine the relative contributions of the mineral and organic phases of dentin to its total buffering capacity and to compare the buffering abilities of normal and caries-affected dentin for acids used in adhesive dentistry. Disks of normal and caries-affected human coronal dentin 0.6 mm thick were prepared. Fifty microL of various acids were applied to the surface of mineralized or completely demineralized dentin for varying lengths of time. They were collected from the surface and combined with water rinses to permit titration of the total amount of acid applied, the amount recovered, the total amount that was taken up by the dentin, and the amount that diffused across dentin into 1 mL of water. Equal volumes of acids were applied to mineralized or demineralized dentin powder or hydroxyapatite powder. About 88% to 90% of applied acid was recovered from the surface; only 10% to 12% of the acid was taken up by dentin. Of the H+ that was taken up, only 1% to 2% actually diffused across 0.6 mm of dentin. Increasing the application time of 37% phosphoric acid did not increase the amount of H+ that diffused across dentin. Increasing the concentration of phosphoric acid from 10% to 65% produced only slight increases in H+ diffusion across dentin. There was no difference in the buffering capacity of normal vs caries-affected dentin disks. Almost all of the buffering capacity of dentin is due to its mineral phase. The high buffering capacity of dentin and the high reactivity of H+ insure that little H+ diffuses through dentin more than 0.6 mm thick.

Buffered Communication Analysis in Distributed Multiparty Sessions

Science.gov (United States)

Deniélou, Pierre-Malo; Yoshida, Nobuko

Many communication-centred systems today rely on asynchronous messaging among distributed peers to make efficient use of parallel execution and resource access. With such asynchrony, the communication buffers can happen to grow inconsiderately over time. This paper proposes a static verification methodology based on multiparty session types which can efficiently compute the upper bounds on buffer sizes. Our analysis relies on a uniform causality audit of the entire collaboration pattern - an examination that is not always possible from each end-point type. We extend this method to design algorithms that allocate communication channels in order to optimise the memory requirements of session executions. From these analyses, we propose two refinements methods which respect buffer bounds: a global protocol refinement that automatically inserts confirmation messages to guarantee stipulated buffer sizes and a local protocol refinement to optimise asynchronous messaging without buffer overflow. Finally our work is applied to overcome a buffer overflow problem of the multi-buffering algorithm.

Heat conductivity of buffer materials

International Nuclear Information System (INIS)

Boergesson, L.; Fredrikson, Anders; Johannesson, L.E.

1994-11-01

The report deals with the thermal conductivity of bentonite based buffer materials. An improved technique for measuring the thermal conductivity of buffer materials is described. Measurements of FLAC calculations applying this technique have led to a proposal of how standardized tests should be conducted and evaluated. The thermal conductivity of bentonite with different void ratio and degree of water saturation has been determined in the following different ways: * Theoretically according to three different investigations by other researchers. * Laboratory measurements with the proposed method. * Results from back-calculated field tests. Comparison and evaluation showed that these results agreed very well, when the buffer material was almost water saturated. However, the influence of the degree of saturation was not very well predicted with the theoretical methods. Furthermore, the field tests showed that the average thermal conductivity in situ of buffer material (compacted to blocks) with low degree of water saturation was lower than expected from laboratory tests. 12 refs, 29 figs, 11 tabs

Efficient Computation of Buffer Capacities for Cyclo-Static Dataflow Graphs

NARCIS (Netherlands)

Wiggers, M.H.; Bekooij, Marco Jan Gerrit; Bekooij, Marco J.G.; Smit, Gerardus Johannes Maria

A key step in the design of cyclo-static real-time systems is the determination of buffer capacities. In our multi-processor system, we apply back-pressure, which means that tasks wait for space in output buffers. Consequently buffer capacities affect the throughput. This requires the derivation of

Efficient Computation of Buffer Capacities for Cyclo-Static Dataflow Graphs

NARCIS (Netherlands)

Wiggers, M.H.; Bekooij, Marco Jan Gerrit; Smit, Gerardus Johannes Maria

2006-01-01

A key step in the design of cyclo-static real-time systems is the determination of buffer capacities. In our multi-processor system, we apply back-pressure, which means that tasks wait for space in output buffers. Consequently buffer capacities affect the throughput. This requires the derivation of

Standard test methods for chemical and spectrochemical analysis of nuclear-Grade silver-indium-cadmium alloys

CERN Document Server

American Society for Testing and Materials. Philadelphia

1990-01-01

1.1 These test methods cover procedures for the chemical and spectrochemical analysis of nuclear grade silver-indium-cadmium (Ag-In-Cd) alloys to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Silver, Indium, and Cadmium by a Titration Method 7-15 Trace Impurities by Carrier-Distillation Spectro- chemical Method 16-22 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard and precautionary statements, see Section 5 and Practices E50. 7.1 This test method is applicable to the determination of silver, indium, and cadmium in alloys of approximately 80 % silver, 15 % indium, and 5 % cadmium used in nuclear reactor control r...

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

CERN Document Server

American Society for Testing and Materials. Philadelphia

2011-01-01

1.1 These test methods cover procedures for subsampling and for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride UF6. Most of these test methods are in routine use to determine conformance to UF6 specifications in the Enrichment and Conversion Facilities. 1.2 The analytical procedures in this document appear in the following order: Note 1—Subcommittee C26.05 will confer with C26.02 concerning the renumbered section in Test Methods C761 to determine how concerns with renumbering these sections, as analytical methods are replaced with stand-alone analytical methods, are best addressed in subsequent publications. Sections Subsampling of Uranium Hexafluoride 7 - 10 Gravimetric Determination of Uranium 11 - 19 Titrimetric Determination of Uranium 20 Preparation of High-Purity U3O 8 21 Isotopic Analysis 22 Isotopic Analysis by Double-Standard Mass-Spectrometer Method 23 - 29 Determination of Hydrocarbons, Chlorocarbons, and Partially Substitut...

Efficiency enhancement of polymer solar cells by applying poly(vinylpyrrolidone) as a cathode buffer layer via spin coating or self-assembly.

Science.gov (United States)

Wang, Haitao; Zhang, Wenfeng; Xu, Chenhui; Bi, Xianghong; Chen, Boxue; Yang, Shangfeng

2013-01-01

A non-conjugated polymer poly(vinylpyrrolidone) (PVP) was applied as a new cathode buffer layer in P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs), by means of either spin coating or self-assembly, resulting in significant efficiency enhancement. For the case of incorporation of PVP by spin coating, power conversion efficiency (PCE) of the ITO/PEDOT:PSS/P3HT:PCBM/PVP/Al BHJ-PSC device (3.90%) is enhanced by 29% under the optimum PVP spin-coating speed of 3000 rpm, which leads to the optimum thickness of PVP layer of ~3 nm. Such an efficiency enhancement is found to be primarily due to the increase of the short-circuit current (J(sc)) (31% enhancement), suggesting that the charge collection increases upon the incorporation of a PVP cathode buffer layer, which originates from the conjunct effects of the formation of a dipole layer between P3HT:PCBM active layer and Al electrodes, the chemical reactions of PVP molecules with Al atoms, and the increase of the roughness of the top Al film. Incorporation of PVP layer by doping PVP directly into the P3HT:PCBM active layer leads to an enhancement of PCE by 13% under the optimum PVP doping ratio of 3%, and this is interpreted by the migration of PVP molecules to the surface of the active layer via self-assembly, resulting in the formation of the PVP cathode buffer layer. While the formation of the PVP cathode buffer layer is fulfilled by both fabrication methods (spin coating and self-assembly), the dependence of the enhancement of the device performance on the thickness of the PVP cathode buffer layer formed by self-assembly or spin coating is different, because of the different aggregation microstructures of the PVP interlayer.

Spectrochemical carriers and the matrix effect: contribution to the spectrographic analysis study of general impurities at trace level in nuclearly pure thorium compounds

International Nuclear Information System (INIS)

Lordello, A.R.

1979-01-01

The relative effectiveness of twenty spectrochemical carriers related to the volatilization behavior of twenty seven general impurities from thorium oxide matrices was studied by means of the moving plate technique. Each carrier was employed in three different concentrations, 2%, 4% and 6%. The relative areas of the volatilization curves have been used for comparing the results. Many experiments were also done to demonstrate the 'matrix effect' in samples having the same chemical composition. The importance of chemical and physical treatments, prior and during the preparation of the thorium oxide, was investigated through a large number of samples by submitting them to spectrochemical analysis. Thorium nitrate and two different thorium oxalate samples, one of which dried in a medium of pH 10, were ignited to ThO 2 according to a temperature versus time program. The presence of nitric acid in thorium nitrate solutions was also studied in connection with the matrix effect. A carrier-distillation method for the determination of twenty five trace elements in thorium compounds was also suggested. Several types of standards had been investigated but the best results were achieved with those prepared from thorium nitrate solutions. Some elements can be determined only by standards synthesized by the dry-mixing technique. The suggested carriers are: 2% NaF (for Ba, Cr, Mg, Sn, V, Cu, Ti, Sr, Mn, Al, Pb, Bi, Ca, Ag, Be, Sb, As, Si, and B), 4% NaCl (for Cd, Co, Fe, Zn and Ni) and 4% KCi (for Na). The method fulfils the requirements of sensitivity for the analysis of trace elements in nuclear grade thorium compounds. (Author) [pt

Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium Sample Handling 8 to 10 Plutonium by Controlled-Potential Coulometry Plutonium by Ceric Sulfate Titration Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Nitrogen by Distillation Spectrophotometry Using Nessler Reagent 11 to 18 Carbon (Total) by Direct Combustion–Thermal Conductivity 19 to 30 Total Chlorine and Fluorine by Pyrohydrolysis 31 to 38 Sulfur by Distillation Spectrophotometry 39 to 47 Plutonium Isotopic Analysis by Mass Spectrometry Rare Earth Elements by Spectroscopy 48 to 55 Trace Elements by Carrier–Distillation Spectroscopy 56 to 63 Impurities by ICP-AES Impurity Elements by Spark-Source Mass Spectrography 64 to 70 Moisture by the Coulomet...

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

CERN Document Server

American Society for Testing and Materials. Philadelphia

1999-01-01

1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Determination of Uranium 7 Specific Gravity by Pycnometry 15-20 Free Acid by Oxalate Complexation 21-27 Determination of Thorium 28 Determination of Chromium 29 Determination of Molybdenum 30 Halogens Separation by Steam Distillation 31-35 Fluoride by Specific Ion Electrode 36-42 Halogen Distillate Analysis: Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 43 Determination of Chloride and Bromide 44 Determination of Sulfur by X-Ray Fluorescence 45 Sulfate Sulfur by (Photometric) Turbidimetry 46 Phosphorus by the Molybdenum Blue (Photometric) Method 54-61 Silicon by the Molybdenum Blue (Photometric) Method 62-69 Carbon by Persulfate Oxidation-Acid Titrimetry 70 Conversion to U3O8 71-74 Boron by ...

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium by Controlled-Potential Coulometry Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Free Acid by Titration in an Oxalate Solution 8 to 15 Free Acid by Iodate Precipitation-Potentiometric Titration Test Method 16 to 22 Uranium by Arsenazo I Spectrophotometric Test Method 23 to 33 Thorium by Thorin Spectrophotometric Test Method 34 to 42 Iron by 1,10-Phenanthroline Spectrophotometric Test Method 43 to 50 Impurities by ICP-AES Chloride by Thiocyanate Spectrophotometric Test Method 51 to 58 Fluoride by Distillation-Spectrophotometric Test Method 59 to 66 Sulfate by Barium Sulfate Turbidimetric Test Method 67 to 74 Isotopic Composition by Mass Spectrom...

Agarose electrophoresis of DNA in discontinuous buffers, using a horizontal slab apparatus and a buffer system with improved properties.

Science.gov (United States)

Zsolnai, A; Orbán, L; Chrambach, A

1993-03-01

Using a horizontal slab apparatus with a buffer in the reservoirs at the level of the gel ("sea-level electrophoresis"), the retrograde discontinuous buffer system reported by Wiltfang et al. for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of proteins was applied to DNA electrophoresis. This application yielded the advantages of an increased displacement rate of the moving boundary front and a decrease in the concentration of the counterion base in the resolving phase, which yielded reduced relative mobility values at equivalent gel concentrations and practicable low buffer concentrations. The change of relative mobilities (Rf) with a variation of field strength is decreased compared to that of the migration rate in the continuous Tris-boric-acid-EDTA (TBE) buffer and thus the robustness of the system is improved, as well as the efficiency of separation. The system of Wiltfang et al. has in common with previously described discontinuous DNA system, that it is able to stack DNA from dilute samples and is insensitive to sample components with lower net mobilities than DNA, such as acetate. However, the variance of Rf at constant current density in the discontinuous buffer system is not improved over that of the migration rate at constant field strength in the continuous TBE buffer.

Spectrochemical analysis of aluminum and its alloys, and S. A. P.; Analisis espectroquimico de aluminio y sus aleaciones y de S.A.P.

Energy Technology Data Exchange (ETDEWEB)

Roca, M

1966-07-01

Three different techniques have been employed for the spectrochemical analysis of aluminum, aluminum alloys, and S.A.P. :1) Point to plane with condensed spark and direct reading spectrometry; from the study on the instantaneous spectral-line intensities a long pre integration time has been established. 1) Powdered samples technique with direct current arc and also direct reading spectrometry; samples are transformed into Al{sub 2}O{sub 3} and mixed with graphite powder (1:1). A complete study on the different elements in aluminium oxide, aluminium sulfate and their mixtures with graphite, has been carried out. 3) Carrier distillation method with photographic recording for very low concentrations of boron and cadmium in S. A.P. (Author) 10 refs.

Direct reading spectrochemical determination of aluminium, iron and silicon in fluorite; Determinacion espectroquimica de lectura directa de aluminio, hierro y silicio en fluorita

Energy Technology Data Exchange (ETDEWEB)

Roca, M

1966-07-01

A quantitative spectrochemical method for the determination of Al, Fe and Si in fluorite has been worked out. The sample was supported in a graphite electrode with crater of 5 mm. in diameter, 2,5 mm deep, and burned by a d.c. are in a direct reading spectrometer. The excitation of samples has been studied without dilution as well as using graphite powder as diluent in the ratios 1:1, 1:4, and 1:9; the latter factor was chosen. Ag, Ca, Co, Cr, Mo and Sn were tested as internal standards. It has not been found any significant inter element effect. It is necessary to use natural fluorite as base material for the standards. (Author) 5 refs.

Spectrochemical pure cerium dioxide preparation and its quality control by inductively coupled plasma and mass spectrometry (ICP/MS)

International Nuclear Information System (INIS)

Da Silva Queiroz, C.A.; De Souza, J.E.; Abrao, A.

1998-01-01

Full text: A simple and economic procedure for the purification until 500 g CeO 2 batch is presented. The purified material will be used as spectrochemical standard. It is obtained by association of the fractional precipitation technique in the system REC 3 /H 2 O 2 /NH 4 OH to enrich the cerium up to 90% and then refined by ion exchange up to 99.9% CeO2. The 99,9% CeO 2 warranty control of purity was accomplished by inductively coupled plasma and mass spectrometry (ICP/ MS) and compared with activation analysis data, exhibiting impurities traces of same values of the international spec pure standard. The following results (average values) for the contaminant rare earths are (ppm):La(36), Pr(19), Nd(161), Sm(11), Eu(5,3),Gd(113),Tb(89),Dy(2),Ho(0.05),Er(1), Tm(0), Yb(11), Lu (19) and Y(2.1), respectively

Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade mixed oxides ((U, Pu)O2)

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade mixed oxides, (U, Pu)O2, powders and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Uranium in the Presence of Pu by Potentiometric Titration Plutonium by Controlled-Potential Coulometry Plutonium by Amperometric Titration with Iron (II) Nitrogen by Distillation Spectrophotometry Using Nessler Reagent 7 to 14 Carbon (Total) by Direct Combustion-Thermal Conductivity 15 to 26 Total Chlorine and Fluorine by Pyrohydrolysis 27 to 34 Sulfur by Distillation-Spectrophotometry 35 to 43 Moisture by the Coulometric, Electrolytic Moisture Analyzer 44 to 51 Isotopic Composition by Mass Spectrometry Rare Earths by Copper Spark Spectroscopy 52 to 59 Trace Impurities by Carrier Distillation Spectroscopy 60 to 69 Impurities by Spark-Source Mass Spectrography 70 to 76 Total Gas in Reactor-Grade Mixed Dioxide P...

Efcient Computation of Buffer Capacities for Cyclo-Static Real-Time Systems with Back-Pressure

NARCIS (Netherlands)

Wiggers, M.H.; Bekooij, Marco; Bekooij, Marco Jan Gerrit; Jansen, P.G.; Smit, Gerardus Johannes Maria

2006-01-01

A key step in the design of cyclo-static real-time systems is the determination of buffer capacities. In our multiprocessor system, we apply back-pressure, which means that tasks wait for space in output buffers. Consequently buffer capacities affect the throughput. This requires the derivation of

Redox Buffer Strength

Science.gov (United States)

de Levie, Robert

1999-04-01

The proper functioning of enzymes in bodily fluids requires that the pH be maintained within rather narrow limits. The first line of defense against large pH fluctuations in such fluids is the passive control provided by the presence of pH buffers. The ability of pH buffers to stabilize the pH is indicated by the buffer value b introduced in 1922 by van Slyke. It is equally important for many enzymes that the redox potential is kept within a narrow range. In that case, stability of the potential is most readily achieved with a redox buffer. In this communication we define the redox buffer strength by analogy with acid-base buffer strength.

Effects of buffer ionization in protein transition volumes.

Science.gov (United States)

Lee, Soyoung; Heerklotz, Heiko; Chalikian, Tigran V

2010-05-01

Protein denaturation events are generally associated with a change in the state of ionization of abnormally titrating groups and, therefore, are coupled with changes in buffer ionization/neutralization equilibria. Consequently, buffer ionization should influence the measured change in volume accompanying protein denaturation. Changes in volume accompanying protein denaturation reflect the differential packing and hydration of polypeptide chains in their native and denatured conformations while also describing the pressure stability of proteins. A characteristic feature of conformational transitions of globular proteins is a near zero change in volume that is comparable in magnitude with the volume of ionization of biologically relevant buffers. Thus, the impact of buffer ionization on the volume of protein denaturation could be very significant with the potential to affect not only its magnitude but also its sign. To investigate this point quantitatively, we performed pressure perturbation calorimetric (PPC) studies of lysozyme and ribonuclease A at pH 3.0 in four buffers differing in their ionization volumes. Our results identify buffer ionization as an important determinant of protein transition volume that needs to be carefully taken into account. We emphasize that the importance of our results is not limited to PPC measurements but is more general and applies to all volumetric investigations, in particular, extending to the derivation of the pressure-temperature phase diagram of protein stability.

The influence of calcium magnesium, and sodium on the spectrographic analysis of natural waters

International Nuclear Information System (INIS)

Diaz Guerra, J. P.; Capdevilla, C.

1969-01-01

The influences of 1000 μg/ml of calcium and sodium and 300 μg/ml of magnesium, on the spectrographic determination of Al, Ba, Cr, Fe, Li , Mn, Ni, Pb, Sr and Ti, minor constituents in natural waters, have been studied, In order to eliminate them, the elements Ga, In, La, Ti and Zn, as well as a mixture containing 30 % Tl-70 % In, have been tested as spectrochemical buffers. (Author) 7 refs

Using fractional order method to generalize strengthening generating operator buffer operator and weakening buffer operator

OpenAIRE

Wu, L.; Liu, S.; Yang, Yingjie

2016-01-01

Traditional integer order buffer operator is extended to fractional order buffer operator, the corresponding relationship between the weakening buffer operator and the strengthening buffer operator is revealed. Fractional order buffer operator not only can generalize the weakening buffer operator and the strengthening buffer operator, but also realize tiny adjustment of buffer effect. The effectiveness of GM(1,1) with the fractional order buffer operator is validated by six cases.

On Tight Separation for Blum Measures Applied to Turing Machine Buffer Complexity

Czech Academy of Sciences Publication Activity Database

Šíma, Jiří; Žák, Stanislav

2017-01-01

Roč. 152, č. 4 (2017), s. 397-409 ISSN 0169-2968 R&D Projects: GA ČR GBP202/12/G061; GA ČR GAP202/10/1333 Institutional support: RVO:67985807 Keywords : Turing machine * hierarchy * buffer complexity * diagonalization Subject RIV: IN - Informatics, Computer Science OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 0.687, year: 2016

Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets

CERN Document Server

American Society for Testing and Materials. Philadelphia

1999-01-01

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets to determine compliance with specifications. 1.2 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear-grade uranium dioxide powder and pellets. 1.4 This test method covers the determination of chlorine and fluorine in nuclear-grade uranium dioxide. With a 1 to 10-g sample, concentrations of 5 to 200 g/g of chlorine and 1 to 200 μg/g of fluorine are determined without interference. 1.5 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 μg. 1.6 This test method covers the determination of nitride nitrogen in uranium dioxide in the range from 10 to 250 μg. 1.7 This test method covers the spectrographic analysis of nuclear-grade UO2 for the 26 elements in the ranges indicated in Table 2. 1.8 For simultaneous determination of trace ele...

Reverse Engineering Applied to Red Human Hair Pheomelanin Reveals Redox-Buffering as a Pro-Oxidant Mechanism

Science.gov (United States)

Kim, Eunkyoung; Panzella, Lucia; Micillo, Raffaella; Bentley, William E.; Napolitano, Alessandra; Payne, Gregory F.

2015-01-01

Pheomelanin has been implicated in the increased susceptibility to UV-induced melanoma for people with light skin and red hair. Recent studies identified a UV-independent pathway to melanoma carcinogenesis and implicated pheomelanin’s pro-oxidant properties that act through the generation of reactive oxygen species and/or the depletion of cellular antioxidants. Here, we applied an electrochemically-based reverse engineering methodology to compare the redox properties of human hair pheomelanin with model synthetic pigments and natural eumelanin. This methodology exposes the insoluble melanin samples to complex potential (voltage) inputs and measures output response characteristics to assess redox activities. The results demonstrate that both eumelanin and pheomelanin are redox-active, they can rapidly (sec-min) and repeatedly redox-cycle between oxidized and reduced states, and pheomelanin possesses a more oxidative redox potential. This study suggests that pheomelanin’s redox-based pro-oxidant activity may contribute to sustaining a chronic oxidative stress condition through a redox-buffering mechanism. PMID:26669666

On buffer overflow duration in a finite-capacity queueing system with multiple vacation policy

Science.gov (United States)

Kempa, Wojciech M.

2017-12-01

A finite-buffer queueing system with Poisson arrivals and generally distributed processing times, operating under multiple vacation policy, is considered. Each time when the system becomes empty, the service station takes successive independent and identically distributed vacation periods, until, at the completion epoch of one of them, at least one job waiting for service is detected in the buffer. Applying analytical approach based on the idea of embedded Markov chain, integral equations and linear algebra, the compact-form representation for the cumulative distribution function (CDF for short) of the first buffer overflow duration is found. Hence, the formula for the CDF of next such periods is obtained. Moreover, probability distributions of the number of job losses in successive buffer overflow periods are found. The considered queueing system can be efficienly applied in modelling energy saving mechanisms in wireless network communication.

Characterization of bottom sediment of Adam bridge for its mineral content by spectrochemical and ICP-OES techniques

International Nuclear Information System (INIS)

Sharma, P.K.; Bassan, M.K.T.; Avhad, D.K.; Singhal, R.K.; UrsaI, G.R.

2012-01-01

Adam's Bridge also known as Rama's Bridge or Rama Setu is a chain of limestone shoals, between Rameswaram Island, off the southeastern coast of Tamil Nadu, India, and Mannar Island, off the northwestern coast of Sri Lanka. Geological evidence suggests that this bridge is a former land connection between India and Sri Lanka. During this work mineral content in the sand sample collected from four different locations were evaluated by using spectrochemical techniques such as FAAS (Flame atomic absorption spectroscopy), FES(Florescence Emission Spectroscopy), ICP-OES (Inductive coupled plasma optical emission spectroscopy) and UV - Visible Spectrophotometry. Various major elements like SiO 2 , Al 2 O 3 , Fe 2 O 3 , MgO, CaO , Na 2 O , K 2 O, minor elements like MnO, TiO 2 , P 2 O 5 and trace elements like Zr O2 ; V 2 O 5 , PbO and U etc. Validation of analytical methodology and reliability of analytical results were carried out by the analysis of the standard reference material. Trace elements were estimated after the selective removal of silica using AAS and ICP-OES technique. (author)

A THEORETICAL DISCUSSION OF THE ECONOMIC EFFECTS OF BUFFER STOCKS AND BUFFER FUNDS

OpenAIRE

Simmons, Phil

1988-01-01

It has been established that the absence of risk markets justifies market intervention in principle. The form of intervention that has been discussed most widely in the literature is the buffer stock. This paper points out that other forms of intervention, specifically buffer funds, are likely to perform better. The analysis shows that buffer funds are likely to outperform buffer stocks because they address market failure more directly. A sub-theme developed in this paper is that since buffer...

Sum-Rate Optimization in a Two-Way Relay Network with Buffering

DEFF Research Database (Denmark)

Liu, Huaping; Popovski, Petar; De Carvalho, Elisabeth

2013-01-01

A Relay Station (RS) uses a buffer to store and process the received data packets before forwarding them. Recently, the buffer has been exploited in one-way relaying to opportunistically schedule the two different links according to their channel quality. The intuition is that, if the channel...... to the destination is poor, then RS stores more data from the source, in order to use it when the channel to the destination is good. We apply this intuition to the case of half-duplex two-way relaying, where the interactions among the buffers and links become more complex. We investigate the sum-rate maximization...

COMBINATIONS OF BUFFER-STOCKS AND BUFFER-FUNDS FOR WOOL PRICE STABILISATION IN AUSTRALIA

OpenAIRE

Moir, Brian; Piggott, Roley R.

1991-01-01

In this paper a preliminary analysis is presented of a combined buffer-fund and buffer-stock as an alternative to a pure buffer-fund or a pure buffer stock for stabilising wool prices. The alternatives analysed are designed so that each provides the same prices to producers as did the Reserve Price Scheme over the period of analysis. Least-cost combinations of policy instruments are derived. The results show that there is considerable potential for cost savings to be made by combining buffer-...

Organellar Calcium Buffers

Science.gov (United States)

Prins, Daniel; Michalak, Marek

2011-01-01

Ca2+ is an important intracellular messenger affecting many diverse processes. In eukaryotic cells, Ca2+ storage is achieved within specific intracellular organelles, especially the endoplasmic/sarcoplasmic reticulum, in which Ca2+ is buffered by specific proteins known as Ca2+ buffers. Ca2+ buffers are a diverse group of proteins, varying in their affinities and capacities for Ca2+, but they typically also carry out other functions within the cell. The wide range of organelles containing Ca2+ and the evidence supporting cross-talk between these organelles suggest the existence of a dynamic network of organellar Ca2+ signaling, mediated by a variety of organellar Ca2+ buffers. PMID:21421925

ssDNA degradation along capillary electrophoresis process using a Tris buffer.

Science.gov (United States)

Ric, Audrey; Ong-Meang, Varravaddheay; Poinsot, Verena; Martins-Froment, Nathalie; Chauvet, Fabien; Boutonnet, Audrey; Ginot, Frédéric; Ecochard, Vincent; Paquereau, Laurent; Couderc, François

2017-06-01

Tris-Acetate buffer is currently used in the selection and the characterization of ssDNA by capillary electrophoresis (CE). By applying high voltage, the migration of ionic species into the capillary generates a current that induces water electrolysis. This phenomenon is followed by the modification of the pH and the production of Tris derivatives. By injecting ten times by capillary electrophoresis ssDNA (50 nM), the whole oligonucleotide was degraded. In this paper, we will show that the Tris buffer in the running vials is modified along the electrophoretic process by electrochemical reactions. We also observed that the composition of the metal ions changes in the running buffer vials. This phenomenon, never described in CE, is important for fluorescent ssDNA analysis using Tris buffer. The oligonucleotides are degraded by electrochemically synthesized species (present in the running Tris vials) until it disappears, even if the separation buffer in the capillary is clean. To address these issues, we propose to use a sodium phosphate buffer that we demonstrate to be electrochemically inactive. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two-Buffer Simulation Games

Directory of Open Access Journals (Sweden)

Milka Hutagalung

2016-07-01

Full Text Available We consider simulation games played between Spoiler and Duplicator on two Büchi automata in which the choices made by Spoiler can be buffered by Duplicator in two different buffers before she executes them on her structure. Previous work on such games using a single buffer has shown that they are useful to approximate language inclusion problems. We study the decidability and complexity and show that games with two buffers can be used to approximate corresponding problems on finite transducers, i.e. the inclusion problem for rational relations over infinite words.

Temperature Buffer Test. Measurements of water content and density of the excavated buffer material

Energy Technology Data Exchange (ETDEWEB)

Johannesson, Lars-Erik [Clay Technology AB, Lund (Sweden)

2010-12-15

TBT (Temperature Buffer Test) is a joint project between SKB/ANDRA and supported by ENRESA (modeling) and DBE (instrumentation), which aims at understanding and modeling the thermo-hydromechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test was carried out at the - 420 m level in Aespoe HRL in a 8 meters deep and 1.76 m diameter deposition hole, with two heaters (3 m long, 0.6 m diameter), surrounded by a MX-80 bentonite buffer and a confining plug on top anchored with 9 rods. It was installed during spring 2003. The bentonite around upper heater was removed during the period October - December 2009 and the buffer around the lower heater was removed during January - Mars 2010. During dismantling of the buffer, samples were taken on which analyses were made. This report describes the work with the deteroemoeination of the water content and the density of the taken samples. Most of the samples were taken from the buffer by core drilling from the upper surface of each installed bentonite block. The cores had a diameter of about 50 mm and a maximum length equal to the original height of the bentonite blocks (about 500 mm). The water content of the buffer was determined by drying a sample at a temperature of 105 deg C for 24 h and the bulk density was determined by weighing a sample both in the air and immerged in paraffin oil with known density. The water content, dry density, degree of saturation and void ratio of the buffer were then plotted. The plots show that all parts of the buffer had taken up water and the degree of saturation of the buffer varied between 90 - 100%. Large variation in the dry density of the buffer was also observed.

Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets

CERN Document Server

American Society for Testing and Materials. Philadelphia

1994-01-01

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Boron by Titrimetry 7 to 13 Separation of Boron for Mass Spectrometry 14 to 19 Isotopic Composition by Mass Spectrometry 20 to 23 Separation of Halides by Pyrohydrolysis 24 to 27 Fluoride by Ion-Selective Electrode 28 to 30 Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 31 to 33 Trace Elements by Emission Spectroscopy 34 to 46 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (F...

Buffer design 2012

International Nuclear Information System (INIS)

Juvankoski, M.

2013-08-01

Posiva's spent nuclear fuel disposal is based on the KBS-3V concept and on the characteristics of the Olkiluoto site. In this concept single canisters containing spent nuclear fuel surrounded by a bentonite buffer are emplaced in individual vertical boreholes drilled in the floor of deposition tunnels in bedrock at about 420 m depth below ground level. Disk type bentonite blocks are installed at the bottom of the hole and on the top of the disposal canister. Ring type bentonite blocks surround the canisters. This report describes the detailed design of the buffer for a KBS-3V repository. The report presents the design basis, the reference design, and summarises the performance analyses carried out for the design. This report addresses aspects concerning the manufacture, quality control, mechanical strength, chemical resistance, thermal dimensioning, handling of buffer components and material ageing phenomena including the effect of radiation. Interaction of buffer and other engineered barriers are included in the study. The long-term evolution of the repository and its effective drivers are considered if they have an impact on the buffer performance but operational safety aspects are also included because they may affect long-term safety. (orig.)

Buffer erosion in dilute groundwater

International Nuclear Information System (INIS)

Schatz, T.; Kanerva, N.; Martikainen, J.; Sane, P.; Olin, M.; Seppaelae, A.; Koskinen, K.

2013-08-01

One scenario of interest for repository safety assessment involves the loss of bentonite buffer material in contact with dilute groundwater flowing through a transmissive fracture interface. In order to examine the extrusion/erosion behavior of bentonite buffer material under such circumstances, a series of experiments were performed in a flow-through, 1 mm aperture, artificial fracture system. These experiments covered a range of solution chemistry (salt concentration and composition), material composition (sodium montmorillonite and admixtures with calcium montmorillonite), and flow velocity conditions. No erosion was observed for sodium montmorillonite against solution compositions from 0.5 g/L to 10 g/L NaCl. No erosion was observed for 50/50 calcium/sodium montmorillonite against 0.5 g/L NaCl. Erosion was observed for both sodium montmorillonite and 50/50 calcium/sodium montmorillonite against solution compositions ≤ 0.25 g/L NaCl. The calculated erosion rates for the tests with the highest levels of measured erosion, i.e., the tests run under the most dilute conditions (ionic strength (IS) < ∼1 mM), were well-correlated to flow velocity, whereas the calculated erosion rates for the tests with lower levels of measured erosion, i.e., the tests run under somewhat less dilute conditions (∼1 mM < IS < ∼4 mM), were not similarly correlated indicating that material and solution composition can significantly affect erosion rates. In every experiment, both erosive and non-erosive, emplaced buffer material extruded into the fracture and was observed to be impermeable to water flowing in the fracture effectively forming an extended diffusive barrier around the intersecting fracture/buffer interface. Additionally, a model which was developed previously to predict the rate of erosion of bentonite buffer material in low ionic strength water in rock fracture environments was applied to three different cases: sodium montmorillonite expansion in a vertical tube, a

Influence of buffer zone concentrations on efficiency in partial filling micellar electrokinetic chromatography.

Science.gov (United States)

Michalke, D; Kolb, S; Welsch, T

2001-05-04

The potential of counter pressure-moderated partial filling micellar electrokinetic chromatography (PF-MEKC) was investigated in this work. Plate numbers of homologous omega-phenylalcohols were measured in a two-plug PF-MEKC system varying the concentrations and hence the ionic strengths of the background buffer compared to the sodium dodecyl sulfate-containing separation buffer and the counter pressure on the cathodic buffer reservoir. It was observed that plate numbers are strongly influenced by both the buffer concentrations and the counter pressure. Highest plate numbers were obtained with a buffer system where the concentrations are adjusted such that the electroosmotic flow velocities in both zones are equal. Differences in the local electroosmotic flow velocities of the zones caused by different buffer concentrations are responsible for tremendously reduced plate numbers. The efficiency drop is explained in several models by the formation of an intersegmental pressure which produces a parabolically shaped laminar flow component in both zones. Thus, the electroosmotic plug-like flow profile is distorted and the efficiency is reduced. The effect of counter pressure on efficiency turned out to be very complex in dependence on the buffer system applied.

Buffer Film Assisted Growth of Dense MWCNTs on Copper Foils for Flexible Electrochemical Applications

Directory of Open Access Journals (Sweden)

Udomdej Pakdee

2017-01-01

Full Text Available The novel Inconel buffer films were prepared on copper foils using unbalance direct current (DC magnetron sputtering. These films were employed as buffer layers for supporting the dense growth of multiwalled carbon nanotubes (MWCNTs. Thermal chemical vapor deposition (CVD with metal alloys such as stainless steel (SS type 304 films was considered to synthesize MWCNTs. To understand the effectiveness of these buffer films, the MWCNTs grown on buffer-free layer were carried out as a comparison. The main problem such as the diffusion of catalysts into the oxide layer of metal substrate during the CVD process was solved together with a creation of good electrical contact between substrate and nanotubes. The morphologies, crystallinities, and electrochemical behaviors of MWCNTs grown on Inconel buffer films with 304 SS catalysts revealed the better results for applying in flexible electrochemical applications.

21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine equivalent...

A Study on Establishment of Buffer Zone of Radioactive Waste Repository

International Nuclear Information System (INIS)

Yoon, Jeong Hyoun; Park, Joo Wan; Ju, Min Su; Kim, Chang Lak; Park, Jin Baek

2008-01-01

A new proposed repository has a final capacity of 800,000 drums radioactive waste. Most of foreign repositories have a general practice of segregating control zones which mainly contributes to classification of degree of control, whether it is called buffer zone or not. Domestic regulatory requirements of establishment of buffer zone in a repository are not much different from those of nuclear power plants for operation period, in which satisfactory design objective or performance objective is the most important factor in determination of the buffer zone. The meaning of buffer zone after closure is a minimum requested area which can prevent inadvertent intruders from leading to non-allowable exposure during institutional control period. Safety assessment with drinking well scenario giving rise to the highest probability of exposure among the intruder's actions can verify fulfillment of the buffer zone which is determined by operational safety of the repository. At present. for the repository to be constructed in a few years, the same procedure and concept as described in this paper are applied that can satisfy regulatory requirements and radiological safety as well. However, the capacity of the repository will be stepwise extended upto 800,000 drums, consequently its layout will be varied too. Timely considerations will be necessary for current boundary of the buffer zone which has been established on the basis of 100,000 drums disposal.

Improving Water Quality With Conservation Buffers

Science.gov (United States)

Lowrance, R.; Dabney, S.; Schultz, R.

2003-12-01

Conservation buffer technologies are new approaches that need wider application. In-field buffer practices work best when used in combination with other buffer types and other conservation practices. Vegetative barriers may be used in combination with edge-of-field buffers to protect and improve their function and longevity by dispersing runoff and encouraging sediment deposition upslope of the buffer. It's important to understand how buffers can be managed to help reduce nutrient transport potential for high loading of nutrients from manure land application sites, A restored riparian wetland buffer retained or removed at least 59 percent of the nitrogen and 66 percent of the phosphorus that entered from an adjacent manure land application site. The Bear Creek National Restoration Demonstration Watershed project in Iowa has been the site of riparian forest buffers and filter strips creation; constructed wetlands to capture tile flow; stream-bank bioengineering; in-stream structures; and controlling livestock grazing. We need field studies that test various widths of buffers of different plant community compositions for their efficacy in trapping surface runoff, reducing nonpoint source pollutants in subsurface waters, and enhancing the aquatic ecosystem. Research is needed to evaluate the impact of different riparian grazing strategies on channel morphology, water quality, and the fate of livestock-associated pathogens and antibiotics. Integrating riparian buffers and other conservation buffers into these models is a key objective in future model development.

Mechanisms of buffer therapy resistance.

Science.gov (United States)

Bailey, Kate M; Wojtkowiak, Jonathan W; Cornnell, Heather H; Ribeiro, Maria C; Balagurunathan, Yoganand; Hashim, Arig Ibrahim; Gillies, Robert J

2014-04-01

Many studies have shown that the acidity of solid tumors contributes to local invasion and metastasis. Oral pH buffers can specifically neutralize the acidic pH of tumors and reduce the incidence of local invasion and metastatic formation in multiple murine models. However, this effect is not universal as we have previously observed that metastasis is not inhibited by buffers in some tumor models, regardless of buffer used. B16-F10 (murine melanoma), LL/2 (murine lung) and HCT116 (human colon) tumors are resistant to treatment with lysine buffer therapy, whereas metastasis is potently inhibited by lysine buffers in MDA-MB-231 (human breast) and PC3M (human prostate) tumors. In the current work, we confirmed that sensitive cells utilized a pH-dependent mechanism for successful metastasis supported by a highly glycolytic phenotype that acidifies the local tumor microenvironment resulting in morphological changes. In contrast, buffer-resistant cell lines exhibited a pH-independent metastatic mechanism involving constitutive secretion of matrix degrading proteases without elevated glycolysis. These results have identified two distinct mechanisms of experimental metastasis, one of which is pH-dependent (buffer therapy sensitive cells) and one which is pH-independent (buffer therapy resistant cells). Further characterization of these models has potential for therapeutic benefit. Copyright © 2014 Neoplasia Press, Inc. Published by Elsevier Inc. All rights reserved.

Assessing critical source areas in watersheds for conservation buffer planning and riparian restoration.

Science.gov (United States)

Qiu, Zeyuan

2009-11-01

A science-based geographic information system (GIS) approach is presented to target critical source areas in watersheds for conservation buffer placement. Critical source areas are the intersection of hydrologically sensitive areas and pollutant source areas in watersheds. Hydrologically sensitive areas are areas that actively generate runoff in the watershed and are derived using a modified topographic index approach based on variable source area hydrology. Pollutant source areas are the areas in watersheds that are actively and intensively used for such activities as agricultural production. The method is applied to the Neshanic River watershed in Hunterdon County, New Jersey. The capacity of the topographic index in predicting the spatial pattern of runoff generation and the runoff contribution to stream flow in the watershed is evaluated. A simple cost-effectiveness assessment is conducted to compare the conservation buffer placement scenario based on this GIS method to conventional riparian buffer scenarios for placing conservation buffers in agricultural lands in the watershed. The results show that the topographic index reasonably predicts the runoff generation in the watershed. The GIS-based conservation buffer scenario appears to be more cost-effective than the conventional riparian buffer scenarios.

Buffer Zone Fact Sheets

Science.gov (United States)

New requirements for buffer zones and sign posting contribute to soil fumigant mitigation and protection for workers and bystanders. The buffer provides distance between the pesticide application site and bystanders, reducing exposure risk.

Power Impact of Loop Buffer Schemes for Biomedical Wireless Sensor Nodes

Directory of Open Access Journals (Sweden)

Francky Catthoor

2012-11-01

Full Text Available Instruction memory organisations are pointed out as one of the major sources of energy consumption in embedded systems. As these systems are characterised by restrictive resources and a low-energy budget, any enhancement in this component allows not only to decrease the energy consumption but also to have a better distribution of the energy budget throughout the system. Loop buffering is an effective scheme to reduce energy consumption in instruction memory organisations. In this paper, the loop buffer concept is applied in real-life embedded applications that are widely used in biomedical Wireless Sensor Nodes, to show which scheme of loop buffer is more suitable for applications with certain behaviour. Post-layout simulations demonstrate that a trade-off exists between the complexity of the loop buffer architecture and the energy savings of utilising it. Therefore, the use of loop buffer architectures in order to optimise the instructionmemory organisation from the energy efficiency point of view should be evaluated carefully, taking into account two factors: (1 the percentage of the execution time of the application that is related to the execution of the loops, and (2 the distribution of the execution time percentage over each one of the loops that form the application.

Basic principles of electrolyte chemistry for microfluidic electrokinetics. Part I: Acid-base equilibria and pH buffers.

Science.gov (United States)

Persat, Alexandre; Chambers, Robert D; Santiago, Juan G

2009-09-07

We review fundamental and applied acid-base equilibrium chemistry useful to microfluidic electrokinetics. We present elements of acid-base equilibrium reactions and derive rules for pH calculation for simple buffers. We also present a general formulation to calculate pH of more complex, arbitrary mixtures of electrolytes, and discuss the effects of ionic strength and temperature on pH calculation. More practically, we offer advice on buffer preparation and on buffer reporting. We also discuss "real world" buffers and likely contamination sources. In particular, we discuss the effects of atmospheric carbon dioxide on buffer systems, namely, the increase in ionic strength and acidification of typical electrokinetic device buffers. In Part II of this two-paper series, we discuss the coupling of acid-base equilibria with electrolyte dynamics and electrochemistry in typical microfluidic electrokinetic systems.

Design and Simulation of Seido Buffer for Analog to Digital Converter (ADC) on Multichannel Analyzer (MCA) Application

International Nuclear Information System (INIS)

Harzawadi Hasim; Maslina Ibrahim; Nolida Yusop; Mohd Ashhar Khalid

2011-01-01

Most of our electronic equipment has buffer, thus this make buffer as one of importance in electronic gadget. This paper introduced Single Ended Input Differential Output (SEIDO) buffer to predict the bias at approximately 2.5 V. For this purpose, the input range between -1 mV to 4 V was implemented. The software used to cascade SEIDO buffer is called LTspice IV; an open source software developed by Linear Technology Incorporation. The component involve in this development was Operational Amplifier (OP AMP) AD826 from Analog Devices Incorporation, capacitor and resistor. Kirchhoffs Current Law and Kirchhoffs Voltage Law was applied to calculated voltage gain and biasing voltage. All design has been verified by LTspice IV. The result produced from simulation was between -0.3 V to 6.3 V with bias roughly at 2.5 V. These results prove that it was capable to drive Analog Digital Converter (ADC) that can subsequently apply for Multichannel Analyzer (MCA). (author)

Qualitative and quantitative assessment of interior moisture buffering by enclosures

DEFF Research Database (Denmark)

Janssen, Hans; Roels, Staf

2009-01-01

The significance of interior humidity in attaining sustainable, durable, healthy and comfortable buildings is increasingly recognised. Given their significant interaction, interior humidity appraisals need a qualitative and/or quantitative assessment of interior moisture buffering. While the effe......The significance of interior humidity in attaining sustainable, durable, healthy and comfortable buildings is increasingly recognised. Given their significant interaction, interior humidity appraisals need a qualitative and/or quantitative assessment of interior moisture buffering. While...... the effective moisture penetration depth and effective capacitance models allow quantified assessment, their reliance on the ‘moisture penetration depth’ necessitates comprehensive material properties and hampers their application to multi-dimensional interior objects. On the other hand, while various recently...... an alternative basis for quantitative evaluation of interior moisture buffering by the effective moisture penetration depth and effective capacitance models. The presented methodology uses simple and fast measurements only and can also be applied to multimaterial and/or multidimensional interior elements....

Buffer salt effects in off-line coupling of capillary electrophoresis and mass spectrometry.

Science.gov (United States)

Marák, Jozef; Stanová, Andrea

2014-05-01

In this work, the impact of buffer salts/matrix effects on the signal in direct injection MS with an electrospray interface (DI-ESI-MS) following pITP fractionation of the sample was studied. A range of buffers frequently used in CE analyses (pH 3-10) was prepared containing 10, 50, and 90% v/v of ACN, respectively. The sets of calibration solutions of cetirizine (an antihistaminic drug with an amphiprotic character) within a 0.05-2.0 mg/L concentration range were prepared in different buffers. The greatest enhancements in the MS signal (in terms of change in the slope of the calibration line) were obtained for the beta-alanine buffer (pH 3.5) in positive ionization and for the borate buffer (pH 9.2) in negative ionization, respectively. The procedure was successfully applied to the analysis of buserelin (a peptidic drug). The slope of the calibration line for solutions containing the beta-alanine buffer with 50% of ACN was 4 times higher than for water or urine, respectively. This study clearly demonstrates that the buffer salt/matrix effects in an offline combination of pITP and DI-ESI-MS can also play a positive role, as they can enhance the signal in MS. A similar influence of the above effects can also be presumed in the CE techniques combined on-line with ESI-MS.

Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

Science.gov (United States)

Wang, Lan; Lin, Xianzhong; Ennaoui, Ahmed; Wolf, Christian; Lux-Steiner, Martha Ch.; Klenk, Reiner

2016-02-01

We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

Signature-based store checking buffer

Science.gov (United States)

Sridharan, Vilas; Gurumurthi, Sudhanva

2015-06-02

A system and method for optimizing redundant output verification, are provided. A hardware-based store fingerprint buffer receives multiple instances of output from multiple instances of computation. The store fingerprint buffer generates a signature from the content included in the multiple instances of output. When a barrier is reached, the store fingerprint buffer uses the signature to verify the content is error-free.

Toward an in vivo dissolution methodology: a comparison of phosphate and bicarbonate buffers.

Science.gov (United States)

Sheng, Jennifer J; McNamara, Daniel P; Amidon, Gordon L

2009-01-01

The purpose of this research was to evaluate the difference between the pharmaceutical phosphate buffers and the gastrointestinal bicarbonates in dissolution of ketoprofen and indomethacin, to illustrate the dependence of buffer differential on biopharmaceutical properties of BCS II weak acids, and to recommend phosphate buffers equivalent to bicarbonates. The intrinsic dissolution rates of ketoprofen and indomethacin were experimentally measured using a rotating disk method at 37 degrees C in USP SIF/FaSSIF and various concentrations of bicarbonates. Theoretical models including an improved reaction plane model and a film model were applied to estimate the surrogate phosphate buffers equivalent to the bicarbonates. Experimental results show that the intrinsic dissolution rates of ketoprofen and indomethacin in USP and FaSSIF phosphate buffers are 1.5-3.0 times that in the 15 mM bicarbonates. Theoretical analysis demonstrates that the buffer differential is largely dependent on the drug pK(a) and second on solubility, and weakly dependent on the drug diffusivity. Further, in accordance with the drug pK(a), solubility and diffusivity, a simple phosphate surrogate was proposed to match an average bicarbonate value (15 mM) of the upper gastrointestinal region. Specifically, phosphate buffers of 13-15 mM and 3-4 mM were recommended for ketoprofen and indomethacin, respectively. For both ketoprofen and indomethacin, the intrinsic dissolution using the phosphate surrogate buffers closely approximated the 15 mM bicarbonate buffer. This work demonstrates the substantial difference between pharmaceutical phosphates and physiological bicarbonates in determining the drug intrinsic dissolution rates of BCS II weak acids, such as ketoprofen and indomethacin. Surrogate phosphates were recommended in order to closely reflect the in vivo dissolution of ketoprofen and indomethacin in gastrointestinal bicarbonates, which has significant implications for defining buffer systems for

Double-layered buffer to enhance the thermal performance in a high-level radioactive waste disposal system

International Nuclear Information System (INIS)

Choi, Heui-Joo; Choi, Jongwon

2008-01-01

A thermal performance is one of the most important factors in the design of a geological disposal system for high-level radioactive wastes. According to the conceptual design of the Korean Reference disposal System, the maximum temperature of its buffer with a domestic Ca-bentonite is close to the thermal criterion, 100 deg. C. In order to improve the thermal conductivity of its buffer, several kinds of additives are compared. Among the additives, graphite shows the best result in that the thermal conductivity of the bentonite block is more than 2.0 W/m deg. C. We introduced the concept of a double-layered buffer instead of a traditional bentonite block in order to use the applied additive more effectively. The thermal analysis, based upon the three-dimensional finite element method, shows that a double-layered buffer could reduce the maximum temperature on a canister's surface by 7 deg. C under identical conditions when compared with a single-layered buffer. An analytical solution was derived to efficiently analyze the effects of a double-layered buffer. The illustrative cases show that the temperature differences due to a double-layered buffer depend on the thickness of the buffer

The W-W02 Oxygen Fugacity Buffer at High Pressures and Temperatures: Implications for f02 Buffering and Metal-silicate Partitioning

Science.gov (United States)

Shofner, G. A.; Campbell, A. J.; Danielson, L.; Righter, K.

2013-01-01

a higher fO2 than the IW buffer at pressures lower than 40 GPa, and the magnitude of this difference decreases at higher pressures. This qualitatively indicates an increasingly lithophile character for W at higher pressures. The WWO buffer was quantitatively applied to W metal-silicate partitioning by using the WWO-IW buffer difference in combination with literature data on W metal-silicate partitioning to model the exchange coefficient (KD) for the Fe-W exchange reaction. This approach captures the pressure dependence of W metal-silicate partitioning using the WWO-IW buffer difference and models the activities of the components in the silicate and metallic phases using an expression of the Gibbs excess energy of mixing. Calculation of KD along a peridotite liquidus predicts a decrease in W siderophility at higher pressures that supports the qualitative behavior predicted by the WWO-IW buffer difference, and agrees with findings of others. Comparing the competing effects of temperature and pressure on W metal-silicate partitioning, our results indicate that pressure exerts a greater effect.

Microchannel electrokinetics of charged analytes in buffered solutions near floating electrodes

DEFF Research Database (Denmark)

Andersen, Mathias Bækbo; Wolfcale, Trevor; Gregersen, Misha Marie

to accurately predict such behavior in these flow regimes. Experimentally, using conventional fluorescence microscopy, we investigated the concentration gradient (as well as the associated electroosmosis, induced-charge electro-osmosis, and electrophoresis) of the charged analyte near the floating electrode......We present both experimental and numerical studies of nonlinear electrokinetic flow of buffered solutions seeded with dilute analytes in a straight microchannel (0.6 μm high, 250 μm wide, and 9000 μm long) with a 0.15 μm high 60 μm wide electrode situated at the bottom center of the channel...... as a function of analyte (1 to 10 μM fluorescein and bodipy) and buffer (1 to 10 mM borate and posphate) concentrations and an externally applied voltage drop (50 to 100 V) along the channel. We have implemented a nonlinear continuum kinetics model of the system involving the electric potential, the buffer flow...

Developing suitable buffers to capture transport cycling behavior

DEFF Research Database (Denmark)

Madsen, Thomas; Schipperijn, Jasper; Christiansen, Lars Breum

2014-01-01

units (e.g., home-buffer-based neighborhoods) are not necessarily representative for environmental exposure. An increased understanding of appropriate neighborhoods is needed. GPS cycling tracks from 78 participants for 7 days form the basis for the development and testing of different neighborhood...... buffers for transport cycling. The percentage of GPS points per square meter was used as indicator of the effectiveness of a series of different buffer types, including home-based network buffers, shortest route to city center buffers, and city center-directed ellipse-shaped buffers. The results show...... center-directed ellipse-shaped buffers yielded better results than traditional home-based network buffer types. The ellipse-shaped buffer types could therefore be considered an alternative to more traditional buffers or administrative units in future studies of transport cycling behavior....

RESEARCH NEEDS IN RIPARIAN BUFFER RESTORATION

Science.gov (United States)

Riparian buffer restorations are used as management tools to produce favorable water quality impacts; moreover, the basis for riparian buffers as an instrument of water quality restoration rests on a relatively firm foundation. However, the extent to which buffers can restore rip...

Volatilization mechanism of certain elements in a method of semiquantitative spectrographic analysis; Mecanismo de volatilizacion de ciertos elementos en un metodo de analisis espectrografico semicuantitativo

Energy Technology Data Exchange (ETDEWEB)

Diaz-Guerra, J P

1972-07-01

The efficiency of the compounds GeO{sub 2}, Li{sub 2}B{sub 4}O{sub 7}, Li{sub 2}CO{sub 3}, SiO{sub 2} and SrCO{sub 3} as spectrochemical buffers, in the development of a semiquantitative spectrographic method of analysis, that can be applied to the determination of 47 elements in different matrices, has been tested. It has been shown that trough the use of Li{sub 2}B{sub 4}O{sub 7} or Geo{sub 2} adequate accuracy is obtained, attaining with the latter the detection of much lower concentrations, specially for the elements Mo. Ti, V and W. In order to account for the different behaviour of these elements their volatilization mechanism has been studied. MoB{sub 2}, TiB{sub 2}, VB{sub 2}.{delta}WB and {epsilon}-WB were found, by x-ray diffraction analysis, to be reaction products in the case of mixtures with Li{sub 2}B{sub 4}O{sub 7}. (Author)

Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

Directory of Open Access Journals (Sweden)

Wang Lan

2016-01-01

Full Text Available We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

A Markov chain analysis of the effectiveness of drum-buffer-rope material flow management in job shop environment

Directory of Open Access Journals (Sweden)

Masoud Rabbani

2015-09-01

Full Text Available The theory of constraints is an approach for production planning and control, which emphasizes on the constraints in the system to increase throughput. The theory of constraints is often referred to as Drum-Buffer-Rope developed originally by Goldratt. Drum-Buffer-Rope uses the drum or constraint to create a schedule based on the finite capacity of the first bottleneck. Because of complexity of the job shop environment, Drum-Buffer-Rope material flow management has very little attention to job shop environment. The objective of this paper is to apply the Drum-Buffer-Rope technique in the job shop environment using a Markov chain analysis to compare traditional method with Drum-Buffer-Rope. Four measurement parameters were considered and the result showed the advantage of Drum-Buffer-Rope approach compared with traditional one.

Buffer sizing for multi-hop networks

KAUST Repository

Shihada, Basem

2014-01-28

A cumulative buffer may be defined for an interference domain in a wireless mesh network and distributed among nodes in the network to maintain or improve capacity utilization of network resources in the interference domain without increasing packet queuing delay times. When an interference domain having communications links sharing resources in a network is identified, a cumulative buffer size is calculated. The cumulative buffer may be distributed among buffers in each node of the interference domain according to a simple division or according to a cost function taking into account a distance of the communications link from the source and destination. The network may be monitored and the cumulative buffer size recalculated and redistributed when the network conditions change.

Buffer-regulated biocorrosion of pure magnesium.

Science.gov (United States)

Kirkland, Nicholas T; Waterman, Jay; Birbilis, Nick; Dias, George; Woodfield, Tim B F; Hartshorn, Richard M; Staiger, Mark P

2012-02-01

Magnesium (Mg) alloys are being actively investigated as potential load-bearing orthopaedic implant materials due to their biodegradability in vivo. With Mg biomaterials at an early stage in their development, the screening of alloy compositions for their biodegradation rate, and hence biocompatibility, is reliant on cost-effective in vitro methods. The use of a buffer to control pH during in vitro biodegradation is recognised as critically important as this seeks to mimic pH control as it occurs naturally in vivo. The two different types of in vitro buffer system available are based on either (i) zwitterionic organic compounds or (ii) carbonate buffers within a partial-CO(2) atmosphere. This study investigated the influence of the buffering system itself on the in vitro corrosion of Mg. It was found that the less realistic zwitterion-based buffer did not form the same corrosion layers as the carbonate buffer, and was potentially affecting the behaviour of the hydrated oxide layer that forms on Mg in all aqueous environments. Consequently it was recommended that Mg in vitro experiments use the more biorealistic carbonate buffering system when possible.

Assisting in Auditing of Buffer Overflow Vulnerabilities via Machine Learning

Directory of Open Access Journals (Sweden)

Qingkun Meng

2017-01-01

Full Text Available Buffer overflow vulnerability is a kind of consequence in which programmers’ intentions are not implemented correctly. In this paper, a static analysis method based on machine learning is proposed to assist in auditing buffer overflow vulnerabilities. First, an extended code property graph is constructed from the source code to extract seven kinds of static attributes, which are used to describe buffer properties. After embedding these attributes into a vector space, five frequently used machine learning algorithms are employed to classify the functions into suspicious vulnerable functions and secure ones. The five classifiers reached an average recall of 83.5%, average true negative rate of 85.9%, a best recall of 96.6%, and a best true negative rate of 91.4%. Due to the imbalance of the training samples, the average precision of the classifiers is 68.9% and the average F1 score is 75.2%. When the classifiers were applied to a new program, our method could reduce the false positive to 1/12 compared to Flawfinder.

Preliminary Study on the Damping Effect of a Lateral Damping Buffer under a Debris Flow Load

Directory of Open Access Journals (Sweden)

Zheng Lu

2017-02-01

Full Text Available Simulating the impact of debris flows on structures and exploring the feasibility of applying energy dissipation devices or shock isolators to reduce the damage caused by debris flows can make great contribution to the design of disaster prevention structures. In this paper, we propose a new type of device, a lateral damping buffer, to reduce the vulnerability of building structures to debris flows. This lateral damping buffer has two mechanisms of damage mitigation: when debris flows impact on a building, it acts as a buffer, and when the structure vibrates due to the impact, it acts as a shock absorber, which can reduce the maximum acceleration response and subsequent vibration respectively. To study the effectiveness of such a lateral damping buffer, an impact test is conducted, which mainly involves a lateral damping buffer attached to a two-degree-of-freedom structure under a simulated debris flow load. To enable the numerical study, the equation of motion of the structure along with the lateral damping buffer is derived. A subsequent parametric study is performed to optimize the lateral damping buffer. Finally, a practical design procedure is also provided.

The Buffer and Backfill Handbook. Part 2: Materials and techniques

International Nuclear Information System (INIS)

Pusch, Roland

2001-12-01

of commercially smectite-rich clays. Chapter 4 deals with the non-clay mineral components of mixtures of such material, termed 'ballast' here, and smectitic clay. Mixtures of this sort can primarily be used for backfilling shafts and tunnels with less tight soil material than the buffer clay but sufficiently low-conductive and expansive to prevent deposition tunnels from serving as effective hydraulic conductors. The chapter also describes major sources, primarily glacial deposits and crushed rock. Chapter 5 deals with the granulometric composition of mixtures of smectitic clay and ballast for achieving good compactability and effective filling of clay in the voids between ballast grains. Focus is on the gradation of the ballast and the density of the clay component since it controls the hydraulic conductivity of the mixtures. Chapter 6 deals with chemical composition and properties of smectitic clays and ballast materials. It is a very comprehensive issue and we will confine ourselves to describe the chemical composition of clays tested by SKB and provide a basis for estimating their chemical stability and physical performance. This latter issue is under investigation and is further treated in Part 3. Chapter 7 gives the basis of selection of suitable buffers and clay/ballast mixtures with respect to their desired performance in a repository. Major physical properties of common commercial smectite-rich clays and clay/ballast mixtures are described in detail and can serve as reference in designing buffers and backfills. Chapter 8 deals with methods for preparing buffer materials, primarily blocks of highly compacted smectite-rich clay materials. Also, major physical properties of compacted blocks are given as a basis of determining the performance of the system of blocks applied in deposition holes before hydration, swelling and homogenisation has started. Chapter 9 describes methods for preparing, applying and compacting clay/ballast mixtures. Examples are given

The Buffer and Backfill Handbook. Part 2: Materials and techniques

Energy Technology Data Exchange (ETDEWEB)

Pusch, Roland [Geodevelopment AB, Lund (Sweden)

2001-12-01

of commercially smectite-rich clays. Chapter 4 deals with the non-clay mineral components of mixtures of such material, termed 'ballast' here, and smectitic clay. Mixtures of this sort can primarily be used for backfilling shafts and tunnels with less tight soil material than the buffer clay but sufficiently low-conductive and expansive to prevent deposition tunnels from serving as effective hydraulic conductors. The chapter also describes major sources, primarily glacial deposits and crushed rock. Chapter 5 deals with the granulometric composition of mixtures of smectitic clay and ballast for achieving good compactability and effective filling of clay in the voids between ballast grains. Focus is on the gradation of the ballast and the density of the clay component since it controls the hydraulic conductivity of the mixtures. Chapter 6 deals with chemical composition and properties of smectitic clays and ballast materials. It is a very comprehensive issue and we will confine ourselves to describe the chemical composition of clays tested by SKB and provide a basis for estimating their chemical stability and physical performance. This latter issue is under investigation and is further treated in Part 3. Chapter 7 gives the basis of selection of suitable buffers and clay/ballast mixtures with respect to their desired performance in a repository. Major physical properties of common commercial smectite-rich clays and clay/ballast mixtures are described in detail and can serve as reference in designing buffers and backfills. Chapter 8 deals with methods for preparing buffer materials, primarily blocks of highly compacted smectite-rich clay materials. Also, major physical properties of compacted blocks are given as a basis of determining the performance of the system of blocks applied in deposition holes before hydration, swelling and homogenisation has started. Chapter 9 describes methods for preparing, applying and compacting clay/ballast mixtures. Examples are

Priority Queue Based Reactive Buffer Management Policy for Delay Tolerant Network under City Based Environments.

Directory of Open Access Journals (Sweden)

Qaisar Ayub

Full Text Available Delay Tolerant Network (DTN multi-copy routing protocols are privileged to create and transmit multiple copies of each message that causes congestion and some messages are dropped. This process is known as reactive drop because messages were dropped re-actively to overcome buffer overflows. The existing reactive buffer management policies apply a single metric to drop source, relay and destine messages. Hereby, selection to drop a message is dubious because each message as source, relay or destine may have consumed dissimilar magnitude of network resources. Similarly, DTN has included time to live (ttl parameter which defines lifetime of message. Hence, when ttl expires then message is automatically destroyed from relay nodes. However, time-to-live (ttl is not applicable on messages reached at their destinations. Moreover, nodes keep replicating messages till ttl expires even-though large number of messages has already been dispersed. In this paper, we have proposed Priority Queue Based Reactive Buffer Management Policy (PQB-R for DTN under City Based Environments. The PQB-R classifies buffered messages into source, relay and destine queues. Moreover, separate drop metric has been applied on individual queue. The experiment results prove that proposed PQB-R has reduced number of messages transmissions, message drop and increases delivery ratio.

Priority Queue Based Reactive Buffer Management Policy for Delay Tolerant Network under City Based Environments.

Science.gov (United States)

Ayub, Qaisar; Ngadi, Asri; Rashid, Sulma; Habib, Hafiz Adnan

2018-01-01

Delay Tolerant Network (DTN) multi-copy routing protocols are privileged to create and transmit multiple copies of each message that causes congestion and some messages are dropped. This process is known as reactive drop because messages were dropped re-actively to overcome buffer overflows. The existing reactive buffer management policies apply a single metric to drop source, relay and destine messages. Hereby, selection to drop a message is dubious because each message as source, relay or destine may have consumed dissimilar magnitude of network resources. Similarly, DTN has included time to live (ttl) parameter which defines lifetime of message. Hence, when ttl expires then message is automatically destroyed from relay nodes. However, time-to-live (ttl) is not applicable on messages reached at their destinations. Moreover, nodes keep replicating messages till ttl expires even-though large number of messages has already been dispersed. In this paper, we have proposed Priority Queue Based Reactive Buffer Management Policy (PQB-R) for DTN under City Based Environments. The PQB-R classifies buffered messages into source, relay and destine queues. Moreover, separate drop metric has been applied on individual queue. The experiment results prove that proposed PQB-R has reduced number of messages transmissions, message drop and increases delivery ratio.

Buffer mass test - Buffer materials

International Nuclear Information System (INIS)

Pusch, R.; Boergesson, L.

1982-08-01

Commercial Na bentonite (MX-80) is the clay component of the buffer material in the heater holes as well of the tunnel backfill. Important characteristics are the clay content, liquid limit, X-ray diffraction pattern, water content, and degree of granulation. The ballast material consists of quartz-rich sand and feldspar-rich filler. The preparation of highly compacted bentonite for the near-field isolation of the canister was made by using isostatic compaction technique. The resulting dense bentonite core was cut into regularly shaped blocks which were arranged around each heater and lowered as one unit - heavily instrumented - in the respective deposition holes. For three of the six holes a narrow slot was left open between the bentonite stack and the rock; for the remaining ones a wider slot was chosen with a fill of soft bentonite powder. Both arrangements are expected to yield an ultimate bulk density which is sufficiently high to fulfil the requirement of a negligible permeability and a sufficient swelling pressure as well as heat conductivity, which are the essential parameters. The tunnel backfill, which consists of a mixture of suitably graded ballast material and MX-80 powder, has a considerably lower swelling pressure and heat conductivity, and a higher permeability, all these parameters still within the requirements of the KBS 2 concept. The various zones with different bentonite/sand ratios and the technique to apply them are described in the final part of the report. (Author)

Buffer protection in the installation phase

International Nuclear Information System (INIS)

Wimelius, Hans; Pusch, Roland

2008-12-01

The research and development of the design and construction of the SKB's repository for final disposal of spent reactor fuel is conducted along several paths ('lines'). Issues concerning the bedrock are dealt with in the 'rock line' and those related to buffer and backfill in deposition holes and tunnels are considered in the 'buffer line' and 'backfill line', respectively. These lines also deal with sub-activities that are coupled to several other lines. One of them includes development of techniques for protecting buffer blocks from moisture and water in the installation phase. Techniques and methods for placement and removal of the 'buffer protection sheet' are dealt with in the 'buffer line'. The removal is, however, considered as being part of the backfilling sequence. Since the performance of the sheet is of fundamental importance to the placement and function of the buffer it deserves particular attention. Thus, the removal of the rubber sheet that serves to protect the buffer blocks in the installation phase may be difficult and can cause significant problems that may require retrieval of already placed canister, buffer and backfill. These matters are in focus in the present report. Arrangements for protecting already placed buffer blocks from moist air and water have been tested in earlier large-scale experiments, i.e. the Prototype Repository project at Aespoe but the experience from them has called for more effective protection of the clay blocks as described in the present report. Focus is on the construction of foundation components at the bottom of the deposition holes required for establishing a tight seal between rock and buffer blocks, and on the protection sheet and arrangements for limiting water pressure on it. Special attention is paid to the drainage of the space between rock and protection sheet that is necessary for avoiding failure of the sheet and to systems for achieving this and for providing alarm signals if the allowed pressure is

The SVT Hit Buffer

International Nuclear Information System (INIS)

Belforte, S.; Dell'Orso, M.; Donati, S.

1996-01-01

The Hit Buffer is part of the Silicon Vertex Tracker, a trigger processor dedicated to the reconstruction of particle trajectories in the Silicon Vertex Detector and the Central Tracking Chamber of the Collider Detector at Fermilab. The Hit Buffer is a high speed data-traffic node, where thousands of words are received in arbitrary order and simultaneously organized in an internal structured data base, to be later promptly retrieved and delivered in response to specific requests. The Hit Buffer is capable of processing data at a rate of 25 MHz, thanks to the use of special fast devices like Cache-Tag RAMs and high performance Erasable Programmable Logic Devices from the XILINX XC7300 family

Low noise buffer amplifiers and buffered phase comparators for precise time and frequency measurement and distribution

Science.gov (United States)

Eichinger, R. A.; Dachel, P.; Miller, W. H.; Ingold, J. S.

1982-01-01

Extremely low noise, high performance, wideband buffer amplifiers and buffered phase comparators were developed. These buffer amplifiers are designed to distribute reference frequencies from 30 KHz to 45 MHz from a hydrogen maser without degrading the hydrogen maser's performance. The buffered phase comparators are designed to intercompare the phase of state of the art hydrogen masers without adding any significant measurement system noise. These devices have a 27 femtosecond phase stability floor and are stable to better than one picosecond for long periods of time. Their temperature coefficient is less than one picosecond per degree C, and they have shown virtually no voltage coefficients.

Electrodialysis operation with buffer solution

Science.gov (United States)

Hryn, John N [Naperville, IL; Daniels, Edward J [Orland Park, IL; Krumdick, Greg K [Crete, IL

2009-12-15

A new method for improving the efficiency of electrodialysis (ED) cells and stacks, in particular those used in chemical synthesis. The process entails adding a buffer solution to the stack for subsequent depletion in the stack during electrolysis. The buffer solution is regenerated continuously after depletion. This buffer process serves to control the hydrogen ion or hydroxide ion concentration so as to protect the active sites of electrodialysis membranes. The process enables electrodialysis processing options for products that are sensitive to pH changes.

Buffer protection in the installation phase

Energy Technology Data Exchange (ETDEWEB)

Wimelius, Hans (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Pusch, Roland (Geodevelopment International AB, Lund (Sweden))

2008-12-15

The research and development of the design and construction of the SKB's repository for final disposal of spent reactor fuel is conducted along several paths ('lines'). Issues concerning the bedrock are dealt with in the 'rock line' and those related to buffer and backfill in deposition holes and tunnels are considered in the 'buffer line' and 'backfill line', respectively. These lines also deal with sub-activities that are coupled to several other lines. One of them includes development of techniques for protecting buffer blocks from moisture and water in the installation phase. Techniques and methods for placement and removal of the 'buffer protection sheet' are dealt with in the 'buffer line'. The removal is, however, considered as being part of the backfilling sequence. Since the performance of the sheet is of fundamental importance to the placement and function of the buffer it deserves particular attention. Thus, the removal of the rubber sheet that serves to protect the buffer blocks in the installation phase may be difficult and can cause significant problems that may require retrieval of already placed canister, buffer and backfill. These matters are in focus in the present report. Arrangements for protecting already placed buffer blocks from moist air and water have been tested in earlier large-scale experiments, i.e. the Prototype Repository project at Aespoe but the experience from them has called for more effective protection of the clay blocks as described in the present report. Focus is on the construction of foundation components at the bottom of the deposition holes required for establishing a tight seal between rock and buffer blocks, and on the protection sheet and arrangements for limiting water pressure on it. Special attention is paid to the drainage of the space between rock and protection sheet that is necessary for avoiding failure of the sheet and to systems for achieving

Thermal resistance of buffer layer in a ceramic wall of MHD generation channel

International Nuclear Information System (INIS)

Nomura, Osami; Ebata, Yoshihiro; Hijikata, Kenichi.

1982-01-01

A wal l model is composed for obtaining the thermal resistance of the buffer layer. A buffer layer of the model is consisted to an adhesive layer and a buffer body. The adhesive layer is made of a copper plate, which is 0.3 mm thick, and adhered to the element by Refractory Method. The adhesive layer is consisted to three layers, i.e., Cu, Cu 2 O and CuO. These three layers seems to give rise to the thermal resistance. The buffer body is made of nickel wires of which radious is 0.4 mm and purity is 99.7%. All of the nickel wires are assembled in one direction which is parallel to a center line of the element, and bundled all together. Occupation ratio of nickel is about 78% in a sectional area of the buffer body. One end of the buffer body is soldered to adhesive layer by silver solder and opposite and is soldered to holder by lead solder. An element of the model is made of magnesia ceramics of which purity is about 99.9% and porosity is about 3%. A holder of the model is made of copper block. Results are as follows: (1) Thermal resistance of the buffer layer is from 1.9 to 2.5K/(W/cm 2 ). (2) Thermal resistance of the adhesive layer is from 0.43 to 0.87K/(W/cm 2 ). (3) Thermal resistance of the buffer body is calculated to about 0.7K/(W/cm 2 ) under the estimation at which the heat flows in the nickel wires only. (4) From above results, thermal resistance of silver soldering layer seems to be same as that of the adhesive layers. The buffer layer needs more value of the thermal resistance in order to apply to the MHD generation channel. Value of the thermal resistance is easily satisfied by changing of material of the buffer body, increase of thickness of the buffer layer and etc. Then this wall appears to be useful to an MHD generation channel wall. (author)

Acid-base buffering in organ preservation solutions as a function of temperature: new parameters for comparing buffer capacity and efficiency.

Science.gov (United States)

Baicu, Simona C; Taylor, Michael J

2002-08-01

Control of acidity and preventing intracellular acidosis are recognized as critical properties of an effective organ preservation solution. Buffer capacity and efficiency are therefore important for comparing the relative merits of preservation fluids for optimum hypothermic storage, but these parameters are not available for the variety of organ preservation solutions of interest in transplantation today. Moreover, buffer capacity is dependent upon both concentration and pH such that buffer capacity is not easily predicted for a complex solution containing multiple buffer species. Using standard electrometric methods to measure acid dissociation constants, this study was undertaken to determine the maximum and relative buffer capacities of a variety of new and commonly used hypothermic preservation solutions as a function of temperature. The reference data provided by these measurements show that comparative buffer capacity and efficiency vary widely between the commonly used solutions. Moreover, the fluids containing zwitterionic sulfonic acid buffers such as Hepes possess superior buffering for alpha-stat pH regulation in the region of physiological importance.

Towards Optimal Buffer Size in Wi-Fi Networks

KAUST Repository

Showail, Ahmad J.

2016-01-19

Buffer sizing is an important network configuration parameter that impacts the quality of data traffic. Falling memory cost and the fallacy that ‘more is better’ lead to over provisioning network devices with large buffers. Over-buffering or the so called ‘bufferbloat’ phenomenon creates excessive end-to-end delay in today’s networks. On the other hand, under-buffering results in frequent packet loss and subsequent under-utilization of network resources. The buffer sizing problem has been studied extensively for wired networks. However, there is little work addressing the unique challenges of wireless environment. In this dissertation, we discuss buffer sizing challenges in wireless networks, classify the state-of-the-art solutions, and propose two novel buffer sizing schemes. The first scheme targets buffer sizing in wireless multi-hop networks where the radio spectral resource is shared among a set of con- tending nodes. Hence, it sizes the buffer collectively and distributes it over a set of interfering devices. The second buffer sizing scheme is designed to cope up with recent Wi-Fi enhancements. It adapts the buffer size based on measured link characteristics and network load. Also, it enforces limits on the buffer size to maximize frame aggregation benefits. Both mechanisms are evaluated using simulation as well as testbed implementation over half-duplex and full-duplex wireless networks. Experimental evaluation shows that our proposal reduces latency by an order of magnitude.

Complexation of buffer constituents with neutral complexation agents: part I. Impact on common buffer properties.

Science.gov (United States)

Riesová, Martina; Svobodová, Jana; Tošner, Zdeněk; Beneš, Martin; Tesařová, Eva; Gaš, Bohuslav

2013-09-17

The complexation of buffer constituents with the complexation agent present in the solution can very significantly influence the buffer properties, such as pH, ionic strength, or conductivity. These parameters are often crucial for selection of the separation conditions in capillary electrophoresis or high-pressure liquid chromatography (HPLC) and can significantly affect results of separation, particularly for capillary electrophoresis as shown in Part II of this paper series (Beneš, M.; Riesová, M.; Svobodová, J.; Tesařová, E.; Dubský, P.; Gaš, B. Anal. Chem. 2013, DOI: 10.1021/ac401381d). In this paper, the impact of complexation of buffer constituents with a neutral complexation agent is demonstrated theoretically as well as experimentally for the model buffer system composed of benzoic acid/LiOH or common buffers (e.g., CHES/LiOH, TAPS/LiOH, Tricine/LiOH, MOPS/LiOH, MES/LiOH, and acetic acid/LiOH). Cyclodextrins as common chiral selectors were used as model complexation agents. We were not only able to demonstrate substantial changes of pH but also to predict the general complexation characteristics of selected compounds. Because of the zwitterion character of the common buffer constituents, their charged forms complex stronger with cyclodextrins than the neutral ones do. This was fully proven by NMR measurements. Additionally complexation constants of both forms of selected compounds were determined by NMR and affinity capillary electrophoresis with a very good agreement of obtained values. These data were advantageously used for the theoretical descriptions of variations in pH, depending on the composition and concentration of the buffer. Theoretical predictions were shown to be a useful tool for deriving some general rules and laws for complexing systems.

SODR Memory Control Buffer Control ASIC

Science.gov (United States)

Hodson, Robert F.

1994-01-01

The Spacecraft Optical Disk Recorder (SODR) is a state of the art mass storage system for future NASA missions requiring high transmission rates and a large capacity storage system. This report covers the design and development of an SODR memory buffer control applications specific integrated circuit (ASIC). The memory buffer control ASIC has two primary functions: (1) buffering data to prevent loss of data during disk access times, (2) converting data formats from a high performance parallel interface format to a small computer systems interface format. Ten 144 p in, 50 MHz CMOS ASIC's were designed, fabricated and tested to implement the memory buffer control function.

Optimizing the product-based availability of a buffered industrial process

International Nuclear Information System (INIS)

Hamada, Michael; Martz, Harry F.; Berg, Eric C.; Koehler, Arthur J.

2006-01-01

Many industrial processes for discrete consumable products consist of a series (or set) of sequential process operations (or subsystems) which are de-coupled by means of in-process storage buffers. Each subsystem of such a process contains one or more parallel coupled or uncoupled operating lanes. We describe the use of a discrete-event simulation model for determining the availability of such a process. We likewise define and use a genetic algorithm to determine process designs and operating rules that have high availability. A 65-variable example, consisting of four operating subsystems with at most four lanes per subsystem, is used to illustrate the method. The results for this and similar real-world applications indicate that, by applying this methodology, it is possible to design buffered industrial processes having high availability

Spectrochemical determination of impurities in zircaloy 2 and 4

International Nuclear Information System (INIS)

Paula Reino, L.C. de; Lordello, A.R.

1987-06-01

A method has been developed for the determination of Hf,Co,Mo,Pb,Ti,V,Al,Si,W,Cu,Mg,Mn,B and Cd in zircaloy 2 and 4. For hafnium determination 10% CuF 2 is added as spectrographic buffer on a previously oxidized zircaloy; the samples are loaded in a shallow cup electrode of Scribner Mullins type and excited in a direct current arc. The carrier distillation technique has been used for the other elements. Better results were obtained with 25% AgCl as carrier. The precision of the method varies from 4% for copper to 29% for boron but it does not exceed 17% for most elements. (Author) [pt

Dynamic mechanical properties of buffer material

International Nuclear Information System (INIS)

Takaji, Kazuhiko; Taniguchi, Wataru

1999-11-01

The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of dynamic triaxial tests, measurement of elastic wave velocity and liquefaction tests that aim at getting hold of dynamic mechanical properties. We can get hold of dependency on the shearing strain of the shearing modulus and hysteresis damping constant, the application for the mechanical model etc. by dynamic triaxial tests, the acceptability of maximum shearing modulus obtained from dynamic triaxial tests etc. by measurement of elastic wave velocity and dynamic strength caused by cyclic stress etc. by liquefaction tests. (author)

Joint optimization of maintenance, buffers and machines in manufacturing lines

Science.gov (United States)

Nahas, Nabil; Nourelfath, Mustapha

2018-01-01

This article considers a series manufacturing line composed of several machines separated by intermediate buffers of finite capacity. The goal is to find the optimal number of preventive maintenance actions performed on each machine, the optimal selection of machines and the optimal buffer allocation plan that minimize the total system cost, while providing the desired system throughput level. The mean times between failures of all machines are assumed to increase when applying periodic preventive maintenance. To estimate the production line throughput, a decomposition method is used. The decision variables in the formulated optimal design problem are buffer levels, types of machines and times between preventive maintenance actions. Three heuristic approaches are developed to solve the formulated combinatorial optimization problem. The first heuristic consists of a genetic algorithm, the second is based on the nonlinear threshold accepting metaheuristic and the third is an ant colony system. The proposed heuristics are compared and their efficiency is shown through several numerical examples. It is found that the nonlinear threshold accepting algorithm outperforms the genetic algorithm and ant colony system, while the genetic algorithm provides better results than the ant colony system for longer manufacturing lines.

The buffer/container experiment: results, synthesis, issues

International Nuclear Information System (INIS)

Graham, J.; Chandler, N.A.; Dixon, D.A.; Roach, P.J.; To, T.; Wan, A.W.L.

1997-12-01

A large in-ground experiment has examined how heat affects the performance of the dense sand bentonite 'buffer' that has been proposed for use in the Canadian Nuclear Fuel Waste Management Program. The experiment was performed by Atomic Energy of Canada Limited at its Underground Research Laboratory, Lac du Bonnet, Manitoba between 1991 and 1994. The experiment placed a full-size heater representing a container of nuclear fuel waste in a 1.24-m diameter borehole filled with buffer below the floor of a room excavated at 240-m depth in granitic rock of the Canadian Shield. The buffer and surrounding rock were extensively instrumented for temperatures, total pressures, water pressures, suctions, and rock displacements. Power was provided to the heater for almost 900 days. The experiment showed that good rock conditions can be pre-selected, a borehole can be drilled, and buffer can be placed at controlled densities and water contents. The instrumentation generally worked well, and an extensive data base was successfully organized. Drying was observed in buffer close to the heater. This caused some desiccation cracking. However the cracks only extended approximately one third of the distance to the buffer-rock interface and did not form an advective pathway. Following sampling at the time of decommissioning, cracked samples of buffer were transported to the laboratory and given access to water. The hydraulic conductivities and swelling pressures of these resaturated samples were very similar to those of uncracked buffer. A good balance was achieved between the mass of water flowing into the experiment from the surrounding rock and the increased mass of water in the buffer. A good understanding was developed of the relationships between suctions, water contents, and total pressures in buffer near the buffer-rock interface. Comparisons between measurements and predictions of measured parameters show that a good understanding has been developed of the processes operating

The buffer/container experiment: results, synthesis, issues

Energy Technology Data Exchange (ETDEWEB)

Graham, J. [Univ. of Manitoba, Dept. of Civil Engineering, Winnipeg, MB (Canada); Chandler, N.A.; Dixon, D.A.; Roach, P.J.; To, T.; Wan, A.W.L

1997-12-01

A large in-ground experiment has examined how heat affects the performance of the dense sand bentonite 'buffer' that has been proposed for use in the Canadian Nuclear Fuel Waste Management Program. The experiment was performed by Atomic Energy of Canada Limited at its Underground Research Laboratory, Lac du Bonnet, Manitoba between 1991 and 1994. The experiment placed a full-size heater representing a container of nuclear fuel waste in a 1.24-m diameter borehole filled with buffer below the floor of a room excavated at 240-m depth in granitic rock of the Canadian Shield. The buffer and surrounding rock were extensively instrumented for temperatures, total pressures, water pressures, suctions, and rock displacements. Power was provided to the heater for almost 900 days. The experiment showed that good rock conditions can be pre-selected, a borehole can be drilled, and buffer can be placed at controlled densities and water contents. The instrumentation generally worked well, and an extensive data base was successfully organized. Drying was observed in buffer close to the heater. This caused some desiccation cracking. However the cracks only extended approximately one third of the distance to the buffer-rock interface and did not form an advective pathway. Following sampling at the time of decommissioning, cracked samples of buffer were transported to the laboratory and given access to water. The hydraulic conductivities and swelling pressures of these resaturated samples were very similar to those of uncracked buffer. A good balance was achieved between the mass of water flowing into the experiment from the surrounding rock and the increased mass of water in the buffer. A good understanding was developed of the relationships between suctions, water contents, and total pressures in buffer near the buffer-rock interface. Comparisons between measurements and predictions of measured parameters show that a good understanding has been developed of the processes

International comparison of observation-specific spatial buffers

DEFF Research Database (Denmark)

Frank, Lawrence D; Fox, Eric H; Ulmer, Jared M

2017-01-01

the relative differences in resulting explanatory power on self-reported physical activity outcomes. BEMs were developed in five countries using 'sausage,' 'detailed-trimmed,' and 'detailed,' network buffers at a distance of 1 km around participant household addresses (n = 5883). RESULTS: BEM values were...... significantly different (p trimmed buffer comparisons and 89% of sausage versus detailed network buffer comparisons. Results showed that BEM coefficients in physical activity models did not differ significantly across buffering methods, and in most cases BEM...

The role of social buffering on chronic disruptions in quality of care: evidence from caregiver-based interventions in foster children.

Science.gov (United States)

Flannery, Jessica E; Beauchamp, Kathryn G; Fisher, Philip A

2017-02-01

There is growing evidence that social support can buffer the physiological stress response, specifically cortisol reactivity. We use a developmental framework to review the importance of social buffering in early childhood, a period of heightened plasticity for programming of the hypothalamic-pituitary-adrenal (HPA) axis. The social environment, in which parents play the largest role in early life, is a critical agent in the developmental trajectory of the HPA axis. A prevailing model of social buffering primarily focuses on the role of social support in the context of acute stressors and cortisol response. This review expands this model to provide evidence of the mechanism of social buffering, or lack thereof, across periods of chronic stress by applying the social buffer model to children involved in the child welfare system. We also highlight current interventions that capitalize on the mechanism of social buffering to modify HPA axis functioning across childhood. Last, we synthesize our findings using the social buffering framework to inform future targeted interventions.

Multi-Buffer Simulations for Trace Language Inclusion

Directory of Open Access Journals (Sweden)

Milka Hutagalung

2016-09-01

Full Text Available We consider simulation games played between Spoiler and Duplicator on two Büchi automata in which the choices made by Spoiler can be buffered by Duplicator in several buffers before she executes them on her structure. We show that the simulation games are useful to approximate the inclusion of trace closures of languages accepted by finite-state automata, which is known to be undecidable. We study the decidability and complexity and show that the game with bounded buffers can be decided in polynomial time, whereas the game with one unbounded and one bounded buffer is highly undecidable. We also show some sufficient conditions on the automata for Duplicator to win the game (with unbounded buffers.

THE BUFFER CAPACITY OF AIRWAY EPITHELIAL SECRETIONS

Directory of Open Access Journals (Sweden)

Dusik eKim

2014-06-01

Full Text Available The pH of airway epithelial secretions influences bacterial killing and mucus properties and is reduced by acidic pollutants, gastric reflux, and respiratory diseases such as cystic fibrosis (CF. The effect of acute acid loads depends on buffer capacity, however the buffering of airway secretions has not been well characterized. In this work we develop a method for titrating micro-scale (30 µl volumes and use it to study fluid secreted by the human airway epithelial cell line Calu-3, a widely used model for submucosal gland serous cells. Microtitration curves revealed that HCO3- is the major buffer. Peak buffer capacity (β increased from 17 to 28 mM/pH during forskolin stimulation, and was reduced by >50% in fluid secreted by cystic fibrosis transmembrane conductance regulator (CFTR-deficient Calu-3 monolayers, confirming an important role of CFTR in HCO3- secretion. Back-titration with NaOH revealed non-volatile buffer capacity due to proteins synthesized and released by the epithelial cells. Lysozyme and mucin concentrations were too low to buffer Calu-3 fluid significantly, however model titrations of porcine gastric mucins at concentrations near the sol-gel transition suggest that mucins may contribute to the buffer capacity of ASL in vivo. We conclude that CFTR-dependent HCO3- secretion and epithelially-derived proteins are the predominant buffers in Calu-3 secretions.

Biochar contribution to soil pH buffer capacity

Science.gov (United States)

Tonutare, Tonu; Krebstein, Kadri; Utso, Maarius; Rodima, Ako; Kolli, Raimo; Shanskiy, Merrit

2014-05-01

, organic matter and type of added carbonizated material. Our study showed that the biochar content has significant role in total pH buffer capacity in soil:biochar system . References. Kimetu, J.M., Lehmann, J., Ngoze, S.O., Mugendi, D.N., Kinyangi, J., Riha, S.J., Verchot, L., Recha, J.W., Pell, A.N. 2008. Reversibility of Soil Productivity Decline with Organic Matter of Differing Quality Along a Degradation Gradient. Ecosystems, 11, 726-739. Krull, E. S., Skjemstad, J.O., Baldock, J.A. 2004 'Functions of Soil Organic Matter and the Effect on Soil Properties'. GRDC report. Project CSO 00029. Mutezo, W.T., 2013. Early crop growth and yield responses of maize (Zea mays) to biochar applied on soil. International Working Paper Series, 13/03, 50 pp.

Programmable pH buffers

Science.gov (United States)

Gough, Dara Van; Huber, Dale L.; Bunker, Bruce C.; Roberts, Mark E.

2017-01-24

A programmable pH buffer comprises a copolymer that changes pK.sub.a at a lower critical solution temperature (LCST) in water. The copolymer comprises a thermally programmable polymer that undergoes a hydrophobic-to-hydrophilic phase change at the LCST and an electrolytic polymer that exhibits acid-base properties that are responsive to the phase change. The programmable pH buffer can be used to sequester CO.sub.2 into water.

A buffer overflow detection based on inequalities solution

International Nuclear Information System (INIS)

Xu Guoai; Zhang Miao; Yang Yixian

2007-01-01

A new buffer overflow detection model based on Inequalities Solution was designed, which is based on analyzing disadvantage of the old buffer overflow detection technique and successfully converting buffer overflow detection to Inequalities Solution. The new model can conquer the disadvantage of the old technique and improve efficiency of buffer overflow detection. (authors)

Magnetorheological elastomer and its application on impact buffer

International Nuclear Information System (INIS)

Fu, J; Yu, M; Zhu, L X; Dong, X M

2013-01-01

In this study, a new magnetorheological elastomer (MRE) based buffer is proposed and its vibration isolation performance is investigated. The MRE buffer with a compact structure is first designed in order to accomplish the maximization of the variable stiffness range. The working characteristics of the MRE buffer are then measured and the model of MRE is established. On the basis of the experimental data, the control model of the MRE buffer is also formulated. A two-degree-of-freedom dynamic model with an MRE buffer is then developed. An intelligent control strategy, human simulated intelligent control (HSIC), is proposed to reduce the impact during the drop crash. Finally, the proposed MRE buffer and controller are validated numerically and experimentally. The results show that the proposed MRE buffer and the control strategy can reduce the impact acceleration effectively.

Cube textured CeO2, BaZrO3 and LaAlO3 buffer layers on Ni based Substrates

International Nuclear Information System (INIS)

Deinhofer, C; Gritzner, G

2006-01-01

CeO 2 , BaZrO 3 as well as LaAlO 3 buffer layers were deposited on {100} Ni + 5 weight-% W substrates by a wet chemical technique. The solutions were prepared by dissolving the metal nitrates or acetates and zirconiumacetylacetonate, respectively, in mixtures of acetic acid, methanol and water. The solutions were applied by dip- or spincoating, dried at 135 deg. C and annealed at temperatures between 900 and 1 400 deg. C depending on the buffer layer for 15 min. under Ar-5% H 2 gas flow. Pole-figure measurements proved the exact texture of each buffer layer. Electron microscopy showed dense and smooth buffer layers

Study of flow profile distortions and efficiency in counter pressure moderated partial filling micellar electrokinetic chromatography in relation to the relative buffer zone lengths.

Science.gov (United States)

Michalke, Daniela; Welsch, Thomas

2002-06-25

The influence of the relative buffer zone lengths on the efficiency was investigated in partial filling micellar electrokinetic chromatography using sodium dodecyl sulfate as separation additive. Varying relative zone lengths were obtained by applying identical initial separation zone lengths but different total lengths of the capillaries. Plate numbers of a homologous series of omega-phenylalcohols were measured to indicate the effect of both a changing relative zone length during the run and a counter pressure applied on the cathodic buffer reservoir. The magnitude and the course of these plate numbers are discussed on the basis of models for flow profile superposition and flow profile deformation which are caused by an intersegmental pressure arising at the boundary between the two buffer zones with different electroosmotic flow velocities. Calculation of the intersegmental pressure and of the resulting laminar flow components in the buffer zones on the basis of some equations for electroosmotic and hydrodynamic flow supported the interpretation that a long background buffer zone should be avoided

The thermodynamic-buffer enzymes.

Science.gov (United States)

Stucki, J W

1980-08-01

Oxidative phosphorylation operates at optimal efficiency if and only if the condition of conductance matching L33/L11 = square root 1-q2 is fulfilled. In this relation L11 is the phenomenological conductance of phosphorylation, L33 the phenomenological conductance of the load, i.e. the irreversible ATP-utilizing processes in the cell, and q the degree of coupling of oxidative phosphorylation driven by respiration. Since during short time intervals L11 and q are constant whereas L33 fluctuates in the cell, oxidative phosphorylation would only rarely operate at optimal efficiency due to violation of conductance matching. This paper demonstrates that the reversible ATP-utilizing reaction catalyzed by adenylate kinase can effectively compensate deviations from conductance matching in the presence of a fluctuating L33 and hence allows oxidative phosphorylation to operate at optimal efficiency in the cell. Since the adenylate kinase reaction was found to buffer a thermodynamic potential, i.e. the phosphate potential, this finding was generalized to the concept of thermodynamic buffering. The thermodynamic buffering ability of the adenylate kinase reaction was demonstrated by experiments with incubated rat-liver mitochondria. Considerations of changes introduced in the entropy production by the adenylate kinase reaction allowed to establish the theoretical framework for thermodynamic buffering. The ability of thermodynamic buffering to compensate deviations from conductance matching in the presence of fluctuating loads was demonstrated by computer simulations. The possibility of other reversible ATP-utilizing reactions, like the ones catalyzed by creatine kinase and arginine kinase, to contribute to thermodynamic buffering is discussed. Finally, the comparison of the theoretically calculated steady-stae cytosolic adenine nucleotide concentrations with experimental data from perfused livers demonstrated that in livers from fed rats conductance matching is fulfilled on a

Doped LZO buffer layers for laminated conductors

Science.gov (United States)

Paranthaman, Mariappan Parans [Knoxville, TN; Schoop, Urs [Westborough, MA; Goyal, Amit [Knoxville, TN; Thieme, Cornelis Leo Hans [Westborough, MA; Verebelyi, Darren T [Oxford, MA; Rupich, Martin W [Framingham, MA

2010-03-23

A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the substrate, the biaxially textured buffer layer comprising LZO and a dopant for mitigating metal diffusion through the LZO, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

Buffer regulation of calcium puff sequences

International Nuclear Information System (INIS)

Fraiman, Daniel; Dawson, Silvina Ponce

2014-01-01

Puffs are localized Ca 2+ signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP 3 ). They are the result of the liberation of Ca 2+ from the endoplasmic reticulum through the coordinated opening of IP 3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca 2+ provides a mechanism that enriches the spatio–temporal dynamics of cytosolic calcium. The expression of different types of buffers along the cell's life provides a tool with which Ca 2+ signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP 3 R-Ca 2+ channels introduced previously to elucidate the effect of buffers on sequences of puffs at the same release site. We obtain analytically the probability laws of the interpuff time and of the number of channels that participate of the puffs. Furthermore, we show that under typical experimental conditions the effect of buffers can be accounted for in terms of a simple inhibiting function. Hence, by exploring different inhibiting functions we are able to study the effect of a variety of buffers on the puff size and interpuff time distributions. We find the somewhat counter-intuitive result that the addition of a fast Ca 2+ buffer can increase the average number of channels that participate of a puff. (paper)

Buffer regulation of calcium puff sequences.

Science.gov (United States)

Fraiman, Daniel; Dawson, Silvina Ponce

2014-02-01

Puffs are localized Ca(2 +) signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP3). They are the result of the liberation of Ca(2 +) from the endoplasmic reticulum through the coordinated opening of IP3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca(2 +) provides a mechanism that enriches the spatio-temporal dynamics of cytosolic calcium. The expression of different types of buffers along the cell's life provides a tool with which Ca(2 +) signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP3R-Ca(2 +) channels introduced previously to elucidate the effect of buffers on sequences of puffs at the same release site. We obtain analytically the probability laws of the interpuff time and of the number of channels that participate of the puffs. Furthermore, we show that under typical experimental conditions the effect of buffers can be accounted for in terms of a simple inhibiting function. Hence, by exploring different inhibiting functions we are able to study the effect of a variety of buffers on the puff size and interpuff time distributions. We find the somewhat counter-intuitive result that the addition of a fast Ca(2 +) buffer can increase the average number of channels that participate of a puff.

Copper variation in Cu(In,Ga)Se{sub 2} solar cells with indium sulphide buffer layer

Energy Technology Data Exchange (ETDEWEB)

Spiering, S., E-mail: stefanie.spiering@zsw-bw.de [Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW) Baden-Wuerttemberg, Industriestrasse 6, 70565 Stuttgart (Germany); Paetel, S.; Kessler, F. [Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW) Baden-Wuerttemberg, Industriestrasse 6, 70565 Stuttgart (Germany); Igalson, M.; Abdel Maksoud, H. [Warsaw University of Technology (WUT), Faculty of Physics, Koszykowa 75, 00-662 Warszawa (Poland)

2015-05-01

In the manufacturing of Cu(In,Ga)Se{sub 2} (CIGS) thin film solar cells the application of a buffer layer on top of the absorber is essential to obtain high efficiency devices. Regarding the roll-to-roll production of CIGS cells and modules a vacuum deposition process for the buffer is preferable to the conventional cadmium sulphide buffer deposited in a chemical bath. Promising results have already been achieved for the deposition of indium sulphide buffer by different vacuum techniques. The solar device performance is very sensitive to the conditions at the absorber-buffer heterojunction. In view of optimization we investigated the influence of the Cu content in the absorber on the current-voltage characteristics. In this work the integral copper content was varied between 19 and 23 at.% in CIGS on glass substrates. An improvement of the cell performance by enhanced open circuit voltage was observed for a reduction to ~ 21 at.% when thermally evaporated indium sulphide was applied as the buffer layer. The influence of stoichiometry deviations on the transport mechanism and secondary barriers in the device was studied using detailed dark and light current-voltage analysis and admittance spectroscopy and compared to the reference CdS-buffered cells. We conclude that the composition of the absorber in the interface region affects current transport in In{sub x}S{sub y}-buffered and CdS-buffered cells in different ways hence optimal Cu content in those two types of devices is different. - Highlights: • Influence of Cu-variation in CIGS cells with In{sub x}S{sub y} buffer layer on cell performance • Enhanced efficiency by slight reduction of Cu-content to 21 at.% • Contribution of tunnelling-enhanced interface recombination for higher Cu-content.

Static mechanical properties of buffer material

International Nuclear Information System (INIS)

Takaji, Kazuhiko; Suzuki, Hideaki

1999-11-01

The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of unconfined compression tests, one-dimensional consolidation tests, consolidated-undrained triaxial compression tests and consolidated-undrained triaxial creep tests that aim at getting hold of static mechanical properties. We can get hold of the relationship between the dry density and tensile stress etc. by Brazilian tests, between the dry density and unconfined compressive strength etc. by unconfined compression tests, between the consolidation stress and void ratio etc. by one-dimensional consolidation tests, the stress pass of each effective confining pressure etc. by consolidated-undrained triaxial compression tests and the axial strain rate with time of each axial stress etc. by consolidated-undrained triaxial creep tests. (author)

Optimization of protein buffer cocktails using Thermofluor.

Science.gov (United States)

Reinhard, Linda; Mayerhofer, Hubert; Geerlof, Arie; Mueller-Dieckmann, Jochen; Weiss, Manfred S

2013-02-01

The stability and homogeneity of a protein sample is strongly influenced by the composition of the buffer that the protein is in. A quick and easy approach to identify a buffer composition which increases the stability and possibly the conformational homogeneity of a protein sample is the fluorescence-based thermal-shift assay (Thermofluor). Here, a novel 96-condition screen for Thermofluor experiments is presented which consists of buffer and additive parts. The buffer screen comprises 23 different buffers and the additive screen includes small-molecule additives such as salts and nucleotide analogues. The utilization of small-molecule components which increase the thermal stability of a protein sample frequently results in a protein preparation of higher quality and quantity and ultimately also increases the chances of the protein crystallizing.

BUFFER CAPACITY IN HETEROGENEOUS MULTICOMPONENT SYSTEMS. REVIEW

Directory of Open Access Journals (Sweden)

Oxana Spinu

2015-12-01

Full Text Available The quantitative basis of the theory of buffer properties for two-phase acid-base buffer systems and for multicomponent heterogeneous systems has been derived. The analytical equations with respect to all components for diverse multicomponent systems were deduced. It has been established, that the buffer capacities of components are mutually proportional.

Buffer lining manufacturing method for radioactive waste container

International Nuclear Information System (INIS)

Kawakami, Susumu; Sugino, Hiroyuki

1998-01-01

A recessed portion is formed on an upper surface of a filler layer made of a buffer powder filled into a container main body, the upper portion of the vessel main body is closed by a shrinkable liquid tight film. It is placed in a pressurizing container and pressed to mold a buffer lining base material integrated with the vessel main body. A flat upper surface and a containing space are formed by shaving to form a buffer lining. A disposing vessel containing radioactive wastes is inserted into the containing space, and the containing space is closed by a buffer block. The upper surface is sealed by a lid. With such a constitution, since a buffer lining integrated with the vessel main body can be formed easily inside the vessel main body, the disposing vessel can be contained in the containing vessel in a state surrounded by the buffer easily and stably without laying or piling over a large quantity of buffer blocks. (T.M.)

Buffer Sizing in 802.11 Wireless Mesh Networks

KAUST Repository

Jamshaid, Kamran; Shihada, Basem; Xia, Li; Levis, Philip

2011-01-01

We analyze the problem of buffer sizing for TCP flows in 802.11-based Wireless Mesh Networks. Our objective is to maintain high network utilization while providing low queueing delays. The problem is complicated by the time-varying capacity of the wireless channel as well as the random access mechanism of 802.11 MAC protocol. While arbitrarily large buffers can maintain high network utilization, this results in large queueing delays. Such delays may affect TCP stability characteristics, and also increase queueing delays for other flows (including real-time flows) sharing the buffer. In this paper we propose sizing link buffers collectively for a set of nodes within mutual interference range called the 'collision domain'. We aim to provide a buffer just large enough to saturate the available capacity of the bottleneck collision domain that limits the carrying capacity of the network. This neighborhood buffer is distributed over multiple nodes that constitute the network bottleneck; a transmission by any of these nodes fully utilizes the available spectral resource for the duration of the transmission. We show that sizing routing buffers collectively for this bottleneck allows us to have small buffers (as low as 2 - 3 packets) at individual nodes without any significant loss in network utilization. We propose heuristics to determine these buffer sizes in WMNs. Our results show that we can reduce the end-to-end delays by 6× to 10× at the cost of losing roughly 5% of the network capacity achievable with large buffers.

Buffer Sizing in 802.11 Wireless Mesh Networks

KAUST Repository

Jamshaid, Kamran

2011-10-01

We analyze the problem of buffer sizing for TCP flows in 802.11-based Wireless Mesh Networks. Our objective is to maintain high network utilization while providing low queueing delays. The problem is complicated by the time-varying capacity of the wireless channel as well as the random access mechanism of 802.11 MAC protocol. While arbitrarily large buffers can maintain high network utilization, this results in large queueing delays. Such delays may affect TCP stability characteristics, and also increase queueing delays for other flows (including real-time flows) sharing the buffer. In this paper we propose sizing link buffers collectively for a set of nodes within mutual interference range called the \\'collision domain\\'. We aim to provide a buffer just large enough to saturate the available capacity of the bottleneck collision domain that limits the carrying capacity of the network. This neighborhood buffer is distributed over multiple nodes that constitute the network bottleneck; a transmission by any of these nodes fully utilizes the available spectral resource for the duration of the transmission. We show that sizing routing buffers collectively for this bottleneck allows us to have small buffers (as low as 2 - 3 packets) at individual nodes without any significant loss in network utilization. We propose heuristics to determine these buffer sizes in WMNs. Our results show that we can reduce the end-to-end delays by 6× to 10× at the cost of losing roughly 5% of the network capacity achievable with large buffers.

Analysis of diffusive mass transport in a cracked buffer

International Nuclear Information System (INIS)

Garisto, N.C.; Garisto, F.

1989-11-01

In the disposal vault design for the Canadian Nuclear Fuel Waste Management Program, cylindrical containers of used nuclear fuel would be placed in vertical boreholes in rock and surrounded with a bentonite-based buffer material. The buffer is expected to absorb and/or retard radionuclides leaching from the fuel after the containers fail. There is some evidence, however, that the buffer may be susceptible to cracking. In this report we investigate numerically the consequences of cracking on uranium diffusion through the buffer. The derivation of the mass-transport equations and the numerical solution method are presented for the solubility-limited diffusion of uranium in a cracked buffer system for both swept-away and semi-impermeable boundary conditions at the rock-buffer interface. The results indicate that for swept-away boundary conditions the total uranium flux through the cracked buffer system is, as expected, greater than through the uncracked buffer. The effect of the cracks is strongly dependent on the ratio D/D eff , where D and D eff are the pore-water and the effective buffer diffusion coefficient, respectively. However, although a decrease in D eff enhances the effect of cracks on the total cumulative flux (relative to the uncracked buffer), it also decreases the total cumulative flux through the cracked buffer system (relative to a cracked buffer with a larger D eff value). Finally, for semi-impermeable boundary conditions, the effect of cracks on the total radionuclide flux is relatively small

BENTO buffer development program in Finland - Key issues

International Nuclear Information System (INIS)

Autio, J.; Korkiala-Tanttu, L.; Vaehaenen, M.; Koskinen, K.; Korkeakoski, P.; Haapala, K.

2010-01-01

Document available in extended abstract form only. Posiva launched a programme, BENTO, to develop technology of using bentonite in spent nuclear fuel repositories. The main purpose of the BENTO programme is to produce buffer designs and verify that they fulfil the requirements, especially safety requirements. To achieve this objective, resources and the level of expertise and know-how has to be increased. There are several uncertainties related to the functioning of the buffer components at present. An issue is defined as being significant if there is sufficient uncertainty that the buffer system might not fulfil the requirements because of the issue. These significant issues need to be resolved in order to develop a proper design and to verify the fulfilment of the requirements. The list of significant issues may change with time. Therefore it is crucial to develop adequate expertise, know-how and laboratory facilities to manage the changes. Moreover, there is confidence that by solving the open issues a defendable construction license application can be submitted in 2012. The basic nature of the programme is a combination of material and process research with the design and manufacturing of buffer components to produce feasible buffer design with proven long-term functional properties. The development work carried out under BENTO-programme has been initially divided into four different projects. During the course of work the number of projects and their content can be adjusted. The four BENTO projects are: 1. Manufacturing (MANU); 2. Design (DESI); 3. Modelling (MODE); 4. Material and Process Research (MARE). BENTO programme aims at producing feasible buffer designs which fulfil the requirements specified in Posiva's requirement management system. The designs are produced in DESI-project by following the design development scheme which starts from specification of design basis and ends in documented detailed designs and therefore DESIgn is specified as one

Flow and transport through a damaged buffer - exploration of the impact of a cemented and an eroded buffer

Energy Technology Data Exchange (ETDEWEB)

Neretnieks, Ivars [Dept. of Chemical Engineering and Technology, Royal Institute of Technology, Stockholm (Sweden)

2006-12-15

The compacted bentonite buffer that surrounds the canister with spent fuel is designed not to allow water to flow through it in any appreciable quantities. Should the buffer be severely damaged water could flow to the canister and bring with it corrosive agent such as sulphide. This could speed up the rate of copper corrosion. Should the canister have a damage or be corroded so that the spent fuel inside the canister comes in contact with the water radionuclides could dissolve in the water and be carried away. Two modes of canister damage and their consequences for solute transport are explored in this report. In one case the buffer can potentially be eroded by the water seeping in the fractures in the surrounding rock and attain a high hydraulic conductivity allowing water to flow through it, at least locally. In another case it is conjectured that the buffer is cemented and becomes brittle. Then a crack could conceivably form in the cemented buffer allowing water to flow through it directly to the canister surface. Both cases are hypothetical although in the erosion case the erosion rate could possibly be quantified. The cases studied are to be seen as exploratory calculations for 'what if' cases. Some worst case assumptions have been used to explore bounding scenarios. Thus for the erosion case it is assumed that the hydraulic conductivity is so high that the buffer exerts negligible resistance to water flow. This implies that all the water that can flow through the fractures intersecting the deposition hole can reach the canister. Similarly for the cemented buffer case it is assumed that the crack in the buffer directly connects the rock fracture to the canister surface. For these circumstances it is found that the flowrate that can enter the deposition hole will be approximately two times as large as the water flow that would pass a projected area equal to that of the deposition hole. Thus if the flux in the rock some distance from the deposition

Flow and transport through a damaged buffer - exploration of the impact of a cemented and an eroded buffer

International Nuclear Information System (INIS)

Neretnieks, Ivars

2006-12-01

The compacted bentonite buffer that surrounds the canister with spent fuel is designed not to allow water to flow through it in any appreciable quantities. Should the buffer be severely damaged water could flow to the canister and bring with it corrosive agent such as sulphide. This could speed up the rate of copper corrosion. Should the canister have a damage or be corroded so that the spent fuel inside the canister comes in contact with the water radionuclides could dissolve in the water and be carried away. Two modes of canister damage and their consequences for solute transport are explored in this report. In one case the buffer can potentially be eroded by the water seeping in the fractures in the surrounding rock and attain a high hydraulic conductivity allowing water to flow through it, at least locally. In another case it is conjectured that the buffer is cemented and becomes brittle. Then a crack could conceivably form in the cemented buffer allowing water to flow through it directly to the canister surface. Both cases are hypothetical although in the erosion case the erosion rate could possibly be quantified. The cases studied are to be seen as exploratory calculations for 'what if' cases. Some worst case assumptions have been used to explore bounding scenarios. Thus for the erosion case it is assumed that the hydraulic conductivity is so high that the buffer exerts negligible resistance to water flow. This implies that all the water that can flow through the fractures intersecting the deposition hole can reach the canister. Similarly for the cemented buffer case it is assumed that the crack in the buffer directly connects the rock fracture to the canister surface. For these circumstances it is found that the flowrate that can enter the deposition hole will be approximately two times as large as the water flow that would pass a projected area equal to that of the deposition hole. Thus if the flux in the rock some distance from the deposition hole is 1

Liquid growth hormone: preservatives and buffers

DEFF Research Database (Denmark)

Kappelgaard, Anne-Marie; Anders, Bojesen; Skydsgaard, Karen

2004-01-01

injection are dependent on the preservative used in the formulation and the concentration of GH. Injection pain may also be related to the buffer substance and injection volume. A liquid formulation of GH, Norditropi SimpleXx, has been developed that dispenses with the need for reconstitution before...... solution. More pain was also reported following large volume injections and following injections with solutions containing high protein concentrations. In summary, optimization of the preservative and buffer content of a liquid GH formulation may reduce injection pain and lead to improved patient...... administration. The formulation uses phenol (3 mg/ml) as a preservative (to protect product from microbial degradation or contamination) and histidine as a buffer. Alternative preservatives used in other GH formulations include m-cresol (9 mg/ml) and benzyl alcohol (3-9 mg/ml). Buffering agents include citrate...

Systematic generation of buffer systems for pH gradient ion exchange chromatography and their application.

Science.gov (United States)

Kröner, Frieder; Hubbuch, Jürgen

2013-04-12

pH gradient protein separations are widely used techniques in the field of protein analytics, of which isoelectric focusing is the most well known application. The chromatographic variant, based on the formation of pH gradients in ion exchange columns is only rarely applied due to the difficulties to form controllable, linear pH gradients over a broad pH range. This work describes a method for the systematic generation of buffer compositions with linear titration curves, resulting in well controllable pH gradients. To generate buffer compositions with linear titration curves an in silico method was successfully developed. With this tool, buffer compositions for pH gradient ion exchange chromatography with pH ranges spanning up to 7.5 pH units were established and successfully validated. Subsequently, the buffer systems were used to characterize the elution behavior of 22 different model proteins in cation and anion exchange pH gradient chromatography. The results of both chromatographic modes as well as isoelectric focusing were compared to describe differences in between the methods. Copyright © 2013 Elsevier B.V. All rights reserved.

Chiral separation of synthetic vicinal diol compounds by capillary zone electrophoresis with borate buffer and beta-cyclodextrin as buffer additive.

Science.gov (United States)

Zhao, Yan; Yang, Xingbin; Jiang, Ru; Sun, Xiaoli; Liu, Wenmin; Zhang, Shengyong

2006-05-01

The investigation on capillary electrophoretic enantioseparation of six synthetic compounds containing vicinal diol groups has been undertaken to acquire the optimum conditions using native beta-cyclodextrin (beta-CD) as chiral selector and borate as a background electrolyte. The separation was carried out in an uncoated capillary (58.5 cm x 75 microm i.d., effective length 48.5 cm) and the effects of several important factors were investigated in detail. The results showed that beta-CD as a chiral selector exhibited good enantioselectivity and that the enantioseparation was greatly influenced by the structure of the diols, the borate concentration and the buffer pH. The optimum performance was obtained for the chiral vicinal diols under the conditions of 200 mM borate buffer of pH 9.8 containing 1.7% beta-CD at an applied voltage of 15 kV and a capillary temperature of 20 degrees C. Under the conditions, four diols were baseline separated with fast analysis time and the good theoretical plate numbers (above 10 x 10(4)) and favorable migration-time reproducibilities (RSDs below 3.0%) were obtained. The separation results were satisfactory.

A parallel buffer tree

DEFF Research Database (Denmark)

Sitchinava, Nodar; Zeh, Norbert

2012-01-01

We present the parallel buffer tree, a parallel external memory (PEM) data structure for batched search problems. This data structure is a non-trivial extension of Arge's sequential buffer tree to a private-cache multiprocessor environment and reduces the number of I/O operations by the number of...... in the optimal OhOf(psortN + K/PB) parallel I/O complexity, where K is the size of the output reported in the process and psortN is the parallel I/O complexity of sorting N elements using P processors....

Biomass carbon, nitrogen and phosphorus stocks in hybrid poplar buffers, herbaceous buffers and natural woodlots in the riparian zone on agricultural land.

Science.gov (United States)

Fortier, Julien; Truax, Benoit; Gagnon, Daniel; Lambert, France

2015-05-01

In many temperate agricultural areas, riparian forests have been converted to cultivated land, and only narrow strips of herbaceous vegetation now buffer many farm streams. The afforestation of these riparian zones has the potential to increase carbon (C) storage in agricultural landscapes by creating a new biomass sink for atmospheric CO2. Occurring at the same time, the storage of nitrogen (N) and phosphorus (P) in plant biomass, is an important water quality function that may greatly vary with types of riparian vegetation. The objectives of this study were (1) to compare C, N and P storage in aboveground, belowground and detrital biomass for three types of riparian vegetation cover (9-year-old hybrid poplar buffers, herbaceous buffers and natural woodlots) across four agricultural sites and (2) to determine potential vegetation cover effects on soil nutrient supply rate in the riparian zone. Site level comparisons suggest that 9-year-old poplar buffers have stored 9-31 times more biomass C, 4-10 times more biomass N, and 3-7 times more biomass P than adjacent non managed herbaceous buffers, with the largest differences observed on the more fertile sites. The conversion of these herbaceous buffers to poplar buffers could respectively increase C, N and P storage in biomass by 3.2-11.9 t/ha/yr, 32-124 kg/ha/yr and 3.2-15.6 kg/ha/yr, over 9 years. Soil NO3 and P supply rates during the summer were respectively 57% and 66% lower in poplar buffers than in adjacent herbaceous buffers, potentially reflecting differences in nutrient storage and cycling between the two buffer types. Biomass C ranged 49-160 t/ha in woodlots, 33-110 t/ha in poplar buffers and 3-4 t/ha in herbaceous buffers. Similar biomass C stocks were found in the most productive poplar buffer and three of the four woodlots studied. Given their large and varied biomass C stocks, conservation of older riparian woodlots is equally important for C balance management in farmland. In addition, the

Moisture Buffer Value of Building Materials

DEFF Research Database (Denmark)

Rode, Carsten; Peuhkuri, Ruut; Time, Berit

2007-01-01

When building materials are in contact with indoor air they have some effect to moderate the variations of indoor humidity in occupied buildings. But so far there has been a lack of a standardized quantity to characterize the moisture buffering capability of materials. It has been the objective o...... is a test protocol which expresses how materials should be tested for determination of their Moisture Buffer Value. Finally, the paper presents some of the results of a Round Robin Test on various typical building materials that has been carried out in the project....... of a recent Nordic project to define such a quantity, and to declare it in the form of a NORDTEST method. The Moisture Buffer Value is the figure that has been developed in the project as a way to appraise the moisture buffer effect of materials, and the value is described in the paper. Also explained...

Thermophysical tests of buffer materials

Energy Technology Data Exchange (ETDEWEB)

Suzuki, H. [ITC, Tokyo (Japan); Taniguchi, Wataru

1999-03-01

Thermodynamic properties of buffer materials were measured for putting in order thermodynamic constants to be used in the near-field thermal analysis. The thermal diffusivity and thermal conductivity were measured as functions of the water content and temperature to deduce the specific heat. The thermal conductivity and specific heat varied significantly as the water content changed. Obtained values of the specific heat agreed well the expected values calculated based on the constituents of the buffer material. Temperature dependence of the thermodynamic constants was found small below 90degC. From the findings, the thermal conductivity and specific heat of the buffer material were formulated as functions of the water content. Thermodynamic study of powdery bentonite was carried out as well with a purpose of use for filling apertures in the artificial barrier. (H. Baba)

Surface Water Protection by Productive Buffers

DEFF Research Database (Denmark)

Christen, Benjamin

Vegetated riparian buffer zones are a widely recommended best management practice in agriculture for protecting surface and coastal waters from diffuse nutrient pollution. On the background of the EU funded research project NitroEurope (NEU; www.NitroEurope.eu), this study concentrates...... on the mitigation of nitrogen pollution in surface and groundwater, using riparian buffer zones for biomass production. The objectives are to map suitable areas for buffer implementation across the six NEU study landscapes, model tentative N-loss mitigation, calculate biomass production potential and economic...... designed for local conditions could be a way of protecting water quality attractive to many stakeholders....

A study on manufacturing and construction method of buffer

International Nuclear Information System (INIS)

Chijimatsu, Masakazu; Sugita, Yutaka; Amemiya, Kiyoshi

1999-09-01

As an engineered barrier system in the geological disposal of high-level waste, multibarrier system is considered. Multibarrier system consists of the vitrified waste, the overpack and the buffer. Bentonite is one of the potential material as the buffer because of its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. In order to evaluate the functions of buffer, a lot of experiments has been conducted. The evaluations of these functions are based on the assumption that the buffer is emplaced or constructed in the disposal tunnel (or disposal pit) properly. Therefore, it is necessary to study on the manufacturing / construction method of buffer. As the manufacturing / construction technology of the buffer, the block installation method and in-situ compaction method, etc, are being investigated. The block installation method is to emplace the buffer blocks manufactured in advance at the ground facility, and construction processes of the block installation method at the underground will be simplified compared with the in-situ compaction method. On the other hand, the in-situ compaction method is to introduce the buffer material with specified water content into the disposal tunnel and to make the buffer with high density at the site using a compaction machine. In regard to the in-situ compaction method, it is necessary to investigate the optimum finished thickness of one layer because it is impossible to construct the buffer at one time. This report describes the results of compaction property test and the summary of the past investigation results in connection with the manufacturing / construction method. Then this report shows the construction method that will be feasible in the actual disposal site. (J.P.N.)

Calculation of the equilibrium pH in a multiple-buffered aqueous solution based on partitioning of proton buffering: a new predictive formula.

Science.gov (United States)

Nguyen, Minhtri K; Kao, Liyo; Kurtz, Ira

2009-06-01

Upon the addition of protons to an aqueous solution containing multiple buffers, the final H+ concentration ([H+]) at equilibrium is determined by the partitioning of added H+ among the various buffer components. In the analysis of acid-base chemistry, the Henderson-Hasselbalch equation and the Stewart strong ion formulation can only describe (rather than predict) the equilibrium pH following a proton load since these formulas calculate the equilibrium pH only when the reactant concentrations at equilibrium(1) 1The term "equilibrium" refers to the steady state proton and reactant concentrations when the buffering of excess protons by the various buffers is complete. are already known. In this regard, it is simpler to directly measure the equilibrium pH rather than measure the equilibrium reactant concentrations to calculate the equilibrium pH. As these formulas cannot predict the final equilibrium [H+] following a proton load to a multiple-buffered aqueous solution, we developed a new quantitative approach for predicting the equilibrium [H+] that is based on the preequilibrium(2)2 The term "preequilibrium" refers to the initial proton and reactant concentrations immediately upon addition of protons and before the buffering of excess protons by the various buffers. concentrations of all buffers in an aqueous solution. The mathematical model used to derive our equation is based on proton transfer buffer equilibria without requiring the incorporation of electroneutrality considerations. The model consists of a quartic polynomial equation that is derived based solely on the partitioning of H+ among the various buffer components. We tested the accuracy of the model using aqueous solutions with various buffers and measured the equilibrium pH values following the addition of HCl. Our results confirmed the accuracy of our new equation (r2 = 1; measured pH vs. predicted pH), indicating that it quantitatively accounts for the underlying acid-base phenomenology.

Calculation of the equilibrium pH in a multiple-buffered aqueous solution based on partitioning of proton buffering: a new predictive formula

Science.gov (United States)

Nguyen, Minhtri K.; Kao, Liyo; Kurtz, Ira

2009-01-01

Upon the addition of protons to an aqueous solution containing multiple buffers, the final H+ concentration ([H+]) at equilibrium is determined by the partitioning of added H+ among the various buffer components. In the analysis of acid-base chemistry, the Henderson-Hasselbalch equation and the Stewart strong ion formulation can only describe (rather than predict) the equilibrium pH following a proton load since these formulas calculate the equilibrium pH only when the reactant concentrations at equilibrium1 1The term “equilibrium” refers to the steady state proton and reactant concentrations when the buffering of excess protons by the various buffers is complete. are already known. In this regard, it is simpler to directly measure the equilibrium pH rather than measure the equilibrium reactant concentrations to calculate the equilibrium pH. As these formulas cannot predict the final equilibrium [H+] following a proton load to a multiple-buffered aqueous solution, we developed a new quantitative approach for predicting the equilibrium [H+] that is based on the preequilibrium22The term “preequilibrium” refers to the initial proton and reactant concentrations immediately upon addition of protons and before the buffering of excess protons by the various buffers. concentrations of all buffers in an aqueous solution. The mathematical model used to derive our equation is based on proton transfer buffer equilibria without requiring the incorporation of electroneutrality considerations. The model consists of a quartic polynomial equation that is derived based solely on the partitioning of H+ among the various buffer components. We tested the accuracy of the model using aqueous solutions with various buffers and measured the equilibrium pH values following the addition of HCl. Our results confirmed the accuracy of our new equation (r2 = 1; measured pH vs. predicted pH), indicating that it quantitatively accounts for the underlying acid-base phenomenology. PMID

Social Buffering of Stress in Development: A Career Perspective

Science.gov (United States)

Gunnar, Megan R.

2016-01-01

This review provides a broad overview of my research group's work on social buffering in human development in the context of the field. Much of the focus is on social buffering of the hypothalamic-pituitary-adrenocortical (HPA) system, one of the two major arms of the mammalian stress system. This focus reflects the centrality of the HPA system in research on social buffering in the fields of developmental psychobiology and developmental science. However, buffering of the cardiovascular and autonomic nervous system is also discussed. The central developmental question in this area derives from attachment theory which argues that the infant's experience of stress and arousal regulation in the context of her early attachment relationships is not an immature form of social buffering experienced in adulthood, but rather the foundation out of which individual differences in the capacity to gain stress relief from social partners emerge. The emergence of social buffering in infancy, changes in social buffering throughout childhood and adolescence, the influence of early experience on later individual differences in social buffering, and critical gaps in our knowledge are described. PMID:28544861

Bus Implementation Using New Low Power PFSCL Tristate Buffers

Directory of Open Access Journals (Sweden)

Neeta Pandey

2016-01-01

Full Text Available This paper proposes new positive feedback source coupled logic (PFSCL tristate buffers suited to bus applications. The proposed buffers use switch to attain high impedance state and modify the load or the current source section. An interesting consequence of this is overall reduction in the power consumption. The proposed tristate buffers consume half the power compared to the available switch based counterpart. The issues with available PFSCL tristate buffers based bus implementation are identified and benefits of employing the proposed tristate buffer topologies are put forward. SPICE simulation results using TSMC 180 nm CMOS technology parameters are included to support the theoretical formulations. The performance of proposed tristate buffer topologies is examined on the basis of propagation delay, output enable time, and power consumption. It is found that one of the proposed tristate buffer topology outperforms the others in terms of all the performance parameters. An examination of behavior of available and the proposed PFSCL tristate buffer topologies under parameter variations and mismatch shows a maximum variation of 14%.

Costs of Producing Biomass from Riparian Buffer Strips

Energy Technology Data Exchange (ETDEWEB)

Turhollow, A.

2000-09-01

Nutrient runoff from poultry litter applied to agricultural fields in the Delmarva Peninsula contributes to high nutrient loadings in Chesapeake Bay. One potential means of ameliorating this problem is the use of riparian buffer strips. Riparian buffer strips intercept overland flows of water, sediments, nutrients, and pollutants; and ground water flows of nutrients and pollutants. Costs are estimated for three biomass systems grown on buffer strips: willow planted at a density of 15,300 trees/ha (6200 trees/acre); poplar planted at a density of 1345 trees/ha (545 trees/acre); and switchgrass. These costs are estimated for five different scenarios: (1) total economic costs, where everything is costed [cash costs, noncash costs (e.g., depreciation), land rent, labor]; (2) costs with Conservation Reserve Program (CRP) payments (which pays 50% of establishment costs and an annual land rent); (3) costs with enhanced CRP payments (which pays 95% of establishment costs and an annual payment of approximately 170% of land rent for trees and 150% of land rent for grasses); (4) costs when buffer strips are required, but harvest of biomass is not required [costs borne by biomass are for yield enhancing activities (e.g., fertilization), harvest, and transport]; and (5) costs when buffer strips are required. and harvest of biomass is required to remove nutrients (costs borne by biomass are for yield enhancing activities and transport). CRP regulations would have to change to allow harvest. Delivered costs of willow, poplar, and switchgrass [including transportation costs of $0.38/GJ ($0.40/million Btu) for switchgrass and $0.57/GJ ($0.60/million Btu) for willow and poplar] at 11.2 dry Mg/ha-year (5 dry tons/acre-year) for the five cost scenarios listed above are [$/GJ ($million BIN)]: (1) 3.30-5.45 (3.45-5.75); (2) 2.30-3.80 (2.45-4.00); (3) 1.70-2.45 (1.80-2.60); (4) l-85-3.80 (1.95-4.05); and (5) 0.80-1.50 (0.85-1.60). At yields of 15.7 to 17.9 GJ/ha-year (7 to 8 dry tons

Buffers for biomass production in temperate European agriculture

DEFF Research Database (Denmark)

Christen, Benjamin; Dalgaard, Tommy

2013-01-01

, environmental pressures from intensive agriculture and policy developments. Use of conservation buffers by farmers outside of designated schemes is limited to date, but the increasing demand for bioenergy and the combination of agricultural production with conservation calls for a much wider implementation....... This paper reviews the biophysical knowledge on buffer functioning and associated ecosystem services. It describes how a three-zone buffer design, with arable fields buffered in combination by grassland, short rotation forestry (SRF) or coppice (SRC) and undisturbed vegetation along water courses, can...... be incorporated into farming landscapes as productive conservation elements and reflects on the potential for successful implementation. Land use plays a much greater role in determining catchment hydrology than soil type: shelterbelts or buffer strips have markedly higher infiltration capacity than arable...

A Buffer Management Issue in Designing SSDs for LFSs

Science.gov (United States)

Kim, Jaegeuk; Seol, Jinho; Maeng, Seungryoul

This letter introduces a buffer management issue in designing SSDs for log-structured file systems (LFSs). We implemented a novel trace-driven SSD simulator in SystemC language, and simulated several SSD architectures with the NILFS2 trace. From the results, we give two major considerations related to the buffer management as follows. (1) The write buffer is used as a buffer not a cache, since all write requests are sequential in NILFS2. (2) For better performance, the main architectural factor is the bus bandwidth, but 332MHz is enough. Instead, the read buffer makes a key role in performance improvement while caching data. To enhance SSDs, accordingly, it is an effective way to make efficient read buffer management policies, and one of the examples is tracking the valid data zone in NILFS2, which can increase the data hit ratio in read buffers significantly.

Managing Multiuser Database Buffers Using Data Mining Techniques

NARCIS (Netherlands)

Feng, L.; Lu, H.J.

2004-01-01

In this paper, we propose a data-mining-based approach to public buffer management for a multiuser database system, where database buffers are organized into two areas – public and private. While the private buffer areas contain pages to be updated by particular users, the public

Buffer Zone Requirements for Soil Fumigant Applications

Science.gov (United States)

Updated pesticide product labels require fumigant users to establish a buffer zone around treated fields to reduce risks to bystanders. Useful information includes tarp testing guidance and a buffer zone calculator.

Leverage Between the Buffering Effect and the Bystander Effect in Social Networking.

Science.gov (United States)

Chiu, Yu-Ping; Chang, Shu-Chen

2015-08-01

This study examined encouraged and inhibited social feedback behaviors based on the theories of the buffering effect and the bystander effect. A system program was used to collect personal data and social feedback from a Facebook data set to test the research model. The results revealed that the buffering effect induced a positive relationship between social network size and feedback gained from friends when people's social network size was under a certain cognitive constraint. For people with a social network size that exceeds this cognitive constraint, the bystander effect may occur, in which having more friends may inhibit social feedback. In this study, two social psychological theories were applied to explain social feedback behavior on Facebook, and it was determined that social network size and social feedback exhibited no consistent linear relationship.

Asymmetric Procyclicality of Chinese Banking and the Countercyclical Buffer of Basel III

Directory of Open Access Journals (Sweden)

Yufeng Li

2015-01-01

Full Text Available Since the global financial crisis of 2007-2008, the importance of the procyclicality in the banking sector has been highlighted. One of the Basel III objectives is to promote countercyclical buffers and reduce procyclicality. We apply time-varying copula combined with GARCH model to test the existence of asymmetric procyclicality of Chinese banking. The results show that the procyclicality of Chinese banking is asymmetric, where the dependence between loan and economy growth is more correlated during the decline stage than the rise stage of economy. Based on this asymmetry, we suggest that the authority can use high frequent index for signalling the start point of releasing countercyclical buffer and accelerate the releasing pace to avoid the supply of credit being constrained by regulatory capital requirements in downturns.

Shock buffer for nuclear control assembly

International Nuclear Information System (INIS)

Bevilacqua, F.

1977-01-01

A shock buffer is provided for the gradual deceleration of a rapidly descending control element assembly in a nuclear reactor. The interactive buffer components are associated respectively with the movable control element assembly and part of the upper guide structure independent of and spaced from the fuel assemblies of the reactor

Kinetics of an acid-base catalyzed reaction (aspartame degradation) as affected by polyol-induced changes in buffer pH and pK values.

Science.gov (United States)

Chuy, S; Bell, L N

2009-01-01

The kinetics of an acid-base catalyzed reaction, aspartame degradation, were examined as affected by the changes in pH and pK(a) values caused by adding polyols (sucrose, glycerol) to phosphate buffer. Sucrose-containing phosphate buffer solutions had a lower pH than that of phosphate buffer alone, which contributed, in part, to reduced aspartame reactivity. A kinetic model was introduced for aspartame degradation that encompassed pH and buffer salt concentrations, both of which change with a shift in the apparent pK(a) value. Aspartame degradation rate constants in sucrose-containing solutions were successfully predicted using this model when corrections (that is, lower pH, lower apparent pK(a) value, buffer dilution from the polyol) were applied. The change in buffer properties (pH, pK(a)) from adding sucrose to phosphate buffer does impact food chemical stability. These effects can be successfully incorporated into predictive kinetic models. Therefore, pH and pK(a) changes from adding polyols to buffer should be considered during food product development.

Universal buffers for use in biochemistry and biophysical experiments

Directory of Open Access Journals (Sweden)

Dewey Brooke

2015-08-01

Full Text Available The use of buffers that mimic biological solutions is a foundation of biochemical and biophysical studies. However, buffering agents have both specific and nonspecific interactions with proteins. Buffer molecules can induce changes in conformational equilibria, dynamic behavior, and catalytic properties merely by their presence in solution. This effect is of concern because many of the standard experiments used to investigate protein structure and function involve changing solution conditions such as pH and/or temperature. In experiments in which pH is varied, it is common practice to switch buffering agents so that the pH is within the working range of the weak acid and conjugate base. If multiple buffers are used, it is not always possible to decouple buffer induced change from pH or temperature induced change. We have developed a series of mixed biological buffers for protein analysis that can be used across a broad pH range, are compatible with biologically relevant metal ions, and avoid complications that may arise from changing the small molecule composition of buffers when pH is used as an experimental variable.

Deflating link buffers in a wireless mesh network

KAUST Repository

Jamshaid, Kamran; Shihada, Basem; Showail, Ahmad; Levis, Philip

2014-01-01

We analyze the problem of buffer sizing for backlogged TCP flows in 802.11-based wireless mesh networks. Our objective is to maintain high network utilization while providing low queueing delays. Unlike wired networks where a single link buffer feeds a bottleneck link, the radio spectral resource in a mesh network is shared among a set of contending mesh routers. We account for this by formulating the buffer size problem as sizing a collective buffer distributed over a set of interfering nodes. In this paper we propose mechanisms for sizing and distributing this collective buffer among the mesh nodes constituting the network bottleneck. Our mechanism factors in the network topology and wireless link rates, improving on pre-set buffer allocations that cannot optimally work across the range of configurations achievable with 802.11 radios. We evaluate our mechanisms using simulations as well as experiments on a testbed. Our results show that we can reduce the RTT of a flow by 6× or more, at the cost of less than 10% drop in end-to-end flow throughput.

Deflating link buffers in a wireless mesh network

KAUST Repository

Jamshaid, Kamran

2014-05-01

We analyze the problem of buffer sizing for backlogged TCP flows in 802.11-based wireless mesh networks. Our objective is to maintain high network utilization while providing low queueing delays. Unlike wired networks where a single link buffer feeds a bottleneck link, the radio spectral resource in a mesh network is shared among a set of contending mesh routers. We account for this by formulating the buffer size problem as sizing a collective buffer distributed over a set of interfering nodes. In this paper we propose mechanisms for sizing and distributing this collective buffer among the mesh nodes constituting the network bottleneck. Our mechanism factors in the network topology and wireless link rates, improving on pre-set buffer allocations that cannot optimally work across the range of configurations achievable with 802.11 radios. We evaluate our mechanisms using simulations as well as experiments on a testbed. Our results show that we can reduce the RTT of a flow by 6× or more, at the cost of less than 10% drop in end-to-end flow throughput.

Design, production and initial state of the buffer

Energy Technology Data Exchange (ETDEWEB)

Boerjesson, Lennart; Gunnarsson, David; Johannesson, Lars-Erik; Jonsson, Esther

2010-12-15

The report is included in a set of Production reports, presenting how the KBS-3 repository is designed, produced and inspected. The set of reports is included in the safety report for the KBS-3 repository and repository facility. The report provides input on the initial state of the buffer for the assessment of the long-term safety, SR-Site. The initial state refers to the properties of the engineered barriers once they have been finally placed in the KBS-3 repository and will not be further handled within the repository facility. In addition, the report provides input to the operational safety report, SR-Operation, on how the buffer shall be handled and installed. The report presents the design premises and reference design of the buffer and verifies the conformity of the reference design to the design premises. It also describes the production of the buffer, from excavation and delivery of buffer material to installation in the deposition hole. Finally, the initial state of the buffer and its conformity to the reference design and design premises is presented

Optimization of the buffer layer of a side polished fiber slab coupler based on 3 D ADI beam propagation method

International Nuclear Information System (INIS)

Lee, Cherl Hee; Kim, Cheol; Park, Jae Hee

2008-01-01

A side polished fiber slab coupler has been widely applied to a sensor, which has the advantages of short response time, simple manufacturing process, and reusability as well as in line fiber component. A new type of a side polished fiber sensor providing remote sensing with an improved performance was also recently developed. The side polished fiber slab coupler is modeled as a fiber to planar waveguide coupler with four layers, including the fiber cladding, a buffer layer, planar waveguide and overlay material. The coupling effects by the buffer layer of a side polished fiber slab coupler are analyzed by using 3 dimensional alternating direction implicit (ADI)beam propagation method, where the refractive index and thickness of the buffer layer were tuned for efficient light coupling. The coupling is easily tuned and more occurred by the refractive index and thickness of the buffer layer for efficient coupling. This study tried to optimize the buffer layer parameters for achieving the desired light coupling and power transfer performance

Urban Runoff: Model Ordinances for Aquatic Buffers

Science.gov (United States)

Aquatic Buffers serve as natural boundaries between local waterways and existing development. The model and example ordinaces below provide suggested language or technical guidance designed to create the most effective stream buffer zones possible.

Heed the head: buffer benefits along headwater streams

Science.gov (United States)

Rhonda Mazza; Deanna (Dede) Olson

2015-01-01

Since the Northwest Forest Plan implemented riparian buffers along non-fish bearing streams in 1994, there have been questions about how wide those buffers need to be to protect aquatic and riparian resources from upland forest management activities. The Density Management and Riparian Buffer Study of western Oregon, also initiated in 1994, examines the effects of...

[Prediction of common buffer catalysis in hydrolysis of fenchlorazole-ethyl].

Science.gov (United States)

Lin, Jing; Chen, Jing-wen; Zhang, Si-yu; Cai, Xi-yun; Qiao, Xian-liang

2008-09-01

The purpose of this study was to elucidate the effects of temperatures, pH levels and buffer catalysis on the hydrolysis of FCE. The hydrolysis of FCE follows first-order kinetics at different pH levels and temperatures. FCE hydrolysis rates are greatly increased at elevated pH levels and temperatures. The maximum contribution of buffer catalysis to the hydrolysis of FCE was assessed based on application of the Bronsted equations for general acid-base catalysis. The results suggest that the buffer solutions play an obvious catalysis role in hydrolysis of FCE and the hydrolysis rates of FCE are quickened by the buffer solutions. Besides, the buffer catalysis capacity of different buffer solutions is diverse, and the buffer catalysis capacity at different pH levels with the same buffer solutions is different, too. The phosphate buffer at pH = 7 shows the maximal buffer catalysis capacity. The hydrolysis rate constants of FCE as a function of temperature and pH, which were remedied by the buffer catalysis factor, were mathematically combined to predict the hydrolytic dissipation of FCE. The equation suggests that the hydrolysis half-lives of FCE ranged from 7 d to 790 d. Hydrolysis metabolites of FCE were identified by liquid chromatography-mass spectrometry. In basic conditions (pH 8-10), fenchlorazole was formed via breakdown of the ester bond of the safener.

Maximizing Expected Achievable Rates for Block-Fading Buffer-Aided Relay Channels

KAUST Repository

Shaqfeh, Mohammad

2016-05-25

In this paper, the long-term average achievable rate over block-fading buffer-aided relay channels is maximized using a hybrid scheme that combines three essential transmission strategies, which are decode-and-forward, compress-and-forward, and direct transmission. The proposed hybrid scheme is dynamically adapted based on the channel state information. The integration and optimization of these three strategies provide a more generic and fundamental solution and give better achievable rates than the known schemes in the literature. Despite the large number of optimization variables, the proposed hybrid scheme can be optimized using simple closed-form formulas that are easy to apply in practical relay systems. This includes adjusting the transmission rate and compression when compress-and-forward is the selected strategy based on the channel conditions. Furthermore, in this paper, the hybrid scheme is applied to three different models of the Gaussian block-fading buffer-aided relay channels, depending on whether the relay is half or full duplex and whether the source and the relay have orthogonal or non-orthogonal channel access. Several numerical examples are provided to demonstrate the achievable rate results and compare them to the upper bounds of the ergodic capacity for each one of the three channel models under consideration.

Maximizing Expected Achievable Rates for Block-Fading Buffer-Aided Relay Channels

KAUST Repository

Shaqfeh, Mohammad; Zafar, Ammar; Alnuweiri, Hussein; Alouini, Mohamed-Slim

2016-01-01

In this paper, the long-term average achievable rate over block-fading buffer-aided relay channels is maximized using a hybrid scheme that combines three essential transmission strategies, which are decode-and-forward, compress-and-forward, and direct transmission. The proposed hybrid scheme is dynamically adapted based on the channel state information. The integration and optimization of these three strategies provide a more generic and fundamental solution and give better achievable rates than the known schemes in the literature. Despite the large number of optimization variables, the proposed hybrid scheme can be optimized using simple closed-form formulas that are easy to apply in practical relay systems. This includes adjusting the transmission rate and compression when compress-and-forward is the selected strategy based on the channel conditions. Furthermore, in this paper, the hybrid scheme is applied to three different models of the Gaussian block-fading buffer-aided relay channels, depending on whether the relay is half or full duplex and whether the source and the relay have orthogonal or non-orthogonal channel access. Several numerical examples are provided to demonstrate the achievable rate results and compare them to the upper bounds of the ergodic capacity for each one of the three channel models under consideration.

On Buffer-Aided Multiple-Access Relay Channel

DEFF Research Database (Denmark)

Liu, Rongkuan; Popovski, Petar; Wang, Gang

2016-01-01

This letter treats uplink scenario where M user equipments (UEs) send to a base station (BS), possibly via a common relay station (RS) that is equipped with a buffer. This is a multiple-access relay channel aided by a buffer. We devise a protocol in which the transmission mode is selected...... entirely at the BS, while simultaneously a number of UEs sends new messages to the BS. The results show that the adaptive selection of direct and buffer-aided relay transmissions leads to significant average throughput gains....

Phosphorus retention in riparian buffers: review of their efficiency.

Science.gov (United States)

Hoffmann, Carl Christian; Kjaergaard, Charlotte; Uusi-Kämppä, Jaana; Hansen, Hans Christian Bruun; Kronvang, Brian

2009-01-01

Ground water and surface water interactions are of fundamental importance for the biogeochemical processes governing phosphorus (P) dynamics in riparian buffers. The four most important conceptual hydrological pathways for P losses from and P retention in riparian buffers are reviewed in this paper: (i) The diffuse flow path with ground water flow through the riparian aquifer, (ii) the overland flow path across the riparian buffer with water coming from adjacent agricultural fields, (iii) irrigation of the riparian buffer with tile drainage water from agricultural fields where disconnected tile drains irrigate the riparian buffer, and (iv) inundation of the riparian buffer (floodplain) with river water during short or longer periods. We have examined how the different flow paths in the riparian buffer influence P retention mechanisms theoretically and from empirical evidence. The different hydrological flow paths determine where and how water-borne P compounds meet and interact with iron and aluminum oxides or other minerals in the geochemical cycling of P in the complex and dynamic environment that constitutes a riparian buffer. The main physical process in the riparian buffer-sedimentation-is active along several flow paths and may account for P retention rates of up to 128 kg P ha(-1) yr(-1), while plant uptake may temporarily immobilize up to 15 kg P ha(-1) yr(-1). Retention of dissolved P in riparian buffers is not as pronounced as retention of particulate P and is often below 0.5 kg P ha(-1) yr(-1). Several studies show significant release of dissolved P (i.e., up to 8 kg P ha(-1) yr(-1)).

The Interplay between Feedback and Buffering in Cellular Homeostasis.

Science.gov (United States)

Hancock, Edward J; Ang, Jordan; Papachristodoulou, Antonis; Stan, Guy-Bart

2017-11-22

Buffering, the use of reservoirs of molecules to maintain concentrations of key molecular species, and negative feedback are the primary known mechanisms for robust homeostatic regulation. To our knowledge, however, the fundamental principles behind their combined effect have not been elucidated. Here, we study the interplay between buffering and negative feedback in the context of cellular homeostasis. We show that negative feedback counteracts slow-changing disturbances, whereas buffering counteracts fast-changing disturbances. Furthermore, feedback and buffering have limitations that create trade-offs for regulation: instability in the case of feedback and molecular noise in the case of buffering. However, because buffering stabilizes feedback and feedback attenuates noise from slower-acting buffering, their combined effect on homeostasis can be synergistic. These effects can be explained within a traditional control theory framework and are consistent with experimental observations of both ATP homeostasis and pH regulation in vivo. These principles are critical for studying robustness and homeostasis in biology and biotechnology. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Continuous processing of recombinant proteins: integration of refolding and purification using simulated moving bed size-exclusion chromatography with buffer recycling.

Science.gov (United States)

Wellhoefer, Martin; Sprinzl, Wolfgang; Hahn, Rainer; Jungbauer, Alois

2014-04-11

Continuous processing of recombinant proteins was accomplished by combining continuous matrix-assisted refolding and purification by tandem simulated moving bed (SMB) size-exclusion chromatography (SEC). Recombinant proteins, N(pro) fusion proteins from inclusion bodies were dissolved with NaOH and refolded in the SMB system with a closed-loop set-up with refolding buffer as the desorbent buffer and buffer recycling of the refolding buffer of the raffinate by tangential flow filtration. For further purification of the refolded proteins, a second SMB operation also based on SEC was added. The whole system could be operated isocratically with refolding buffer as the desorbent buffer, and buffer recycling could also be applied in the purification step. Thus, a significant reduction in buffer consumption was achieved. The system was evaluated with two proteins, the N(pro) fusion pep6His and N(pro) fusion MCP-1. Refolding solution, which contained residual N(pro) fusion peptide, the cleaved autoprotease N(pro), and the cleaved target peptide was used as feed solution. Full separation of the cleaved target peptide from residual proteins was achieved at a purity and recovery in the raffinate and extract, respectively, of approximately 100%. In addition, more than 99% of the refolding buffer of the raffinate was recycled. A comparison of throughput, productivity, and buffer consumption of the integrated continuous process with two batch processes demonstrated that up to 60-fold higher throughput, up to 180-fold higher productivity, and at least 28-fold lower buffer consumption can be obtained by the integrated continuous process, which compensates for the higher complexity. Copyright © 2014 Elsevier B.V. All rights reserved.

Methods for improved growth of group III nitride buffer layers

Science.gov (United States)

Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

2014-07-15

Methods are disclosed for growing high crystal quality group III-nitride epitaxial layers with advanced multiple buffer layer techniques. In an embodiment, a method includes forming group III-nitride buffer layers that contain aluminum on suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. A hydrogen halide or halogen gas is flowing into the growth zone during deposition of buffer layers to suppress homogeneous particle formation. Some combinations of low temperature buffers that contain aluminum (e.g., AlN, AlGaN) and high temperature buffers that contain aluminum (e.g., AlN, AlGaN) may be used to improve crystal quality and morphology of subsequently grown group III-nitride epitaxial layers. The buffer may be deposited on the substrate, or on the surface of another buffer. The additional buffer layers may be added as interlayers in group III-nitride layers (e.g., GaN, AlGaN, AlN).

Primavera Ring. Management perspectives on La Primavera forest buffer zone, from the cultural landscapes approach

Directory of Open Access Journals (Sweden)

Pedro Alcocer Santos

2016-06-01

Full Text Available The current article intends to high light the need to implement a buffer zone for La Primavera Forest,  Biosphere reserve MaB UNESCO in Guadalajara, Jalisco. The criteria to develop this transition zone is based on understanding this territory as a Cultural Landscape. Seeking common ground between Biosphere Reserves and Cultural Landscapes criteria to organize the management and development of the buffer zone. To understand the opponents of city development and forest preservation as complementary elements, a paradigm shift is needed. This is an applied research from the ITESO, and it is structured as a Think Tank that involves society, government and academy.

Mechanisms of social buffering of fear in zebrafish.

Science.gov (United States)

Faustino, Ana I; Tacão-Monteiro, André; Oliveira, Rui F

2017-03-31

Some humans thrive whereas others resign when exposed to threatening situations throughout life. Social support has been identified as an important modulator of these discrepancies in human behaviour, and other social animals also exhibit phenomena in which individuals recover better from aversive events when conspecifics are present - aka social buffering. Here we studied social buffering in zebrafish, by exposing focal fish to an aversive stimulus (alarm substance - AS) either in the absence or presence of conspecific cues. When exposed to AS in the presence of both olfactory (shoal water) and visual (sight of shoal) conspecific cues, focal fish exhibited a lower fear response than when tested alone, demonstrating social buffering in zebrafish. When separately testing each cue's effectiveness, we verified that the visual cue was more effective than the olfactory in reducing freezing in a persistent threat scenario. Finally, we verified that social buffering was independent of shoal size and coincided with a distinct pattern of co-activation of brain regions known to be involved in mammalian social buffering. Thus, this study suggests a shared evolutionary origin for social buffering in vertebrates, bringing new evidence on the behavioural, sensory and neural mechanisms underlying this phenomenon.

Evaluation on elution feature of bentonite buffer materials

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, Hirohisa; Kanno, Takeshi; Matsumoto, Kazuhiro

1997-09-01

In order to evaluate long term physical stability of artificial barrier in land disposal of high level radioactive wastes, it is necessary to know quantitatively elution behavior of buffering materials from disposal road (or cavity) to circumferential rock crack. When elution of the buffer material occurs on large scale, amount of bentonite in the disposal road (or cavity) reduces and reduction of various functions expected to the buffer materials is presumed. According to specification examples of road transverse arrangement and disposal vertical arrangement systems, evaluation on elution amount of the buffer materials at disposal environment was conducted. Opening width of rock crack in the disposal environment was supposed to be 0.5 mm. As a result, obtained mass elution ratios of the buffer materials due to extrusion phenomenon were 0.04 to 0.2% after 10,000 year and 2 to 12% after 1,000,000 years. (G.K.)

Visualization of Buffer Capacity with 3-D "Topo" Surfaces: Buffer Ridges, Equivalence Point Canyons and Dilution Ramps

Science.gov (United States)

Smith, Garon C.; Hossain, Md Mainul

2016-01-01

BufCap TOPOS is free software that generates 3-D topographical surfaces ("topos") for acid-base equilibrium studies. It portrays pH and buffer capacity behavior during titration and dilution procedures. Topo surfaces are created by plotting computed pH and buffer capacity values above a composition grid with volume of NaOH as the x axis…

Scientific Approach and Inquiry Learning Model in the Topic of Buffer Solution: A Content Analysis

Science.gov (United States)

Kusumaningrum, I. A.; Ashadi, A.; Indriyanti, N. Y.

2017-09-01

Many concepts in buffer solution cause student’s misconception. Understanding science concepts should apply the scientific approach. One of learning models which is suitable with this approach is inquiry. Content analysis was used to determine textbook compatibility with scientific approach and inquiry learning model in the concept of buffer solution. By using scientific indicator tools (SIT) and Inquiry indicator tools (IIT), we analyzed three chemistry textbooks grade 11 of senior high school labeled as P, Q, and R. We described how textbook compatibility with scientific approach and inquiry learning model in the concept of buffer solution. The results show that textbook P and Q were very poor and book R was sufficient because the textbook still in procedural level. Chemistry textbooks used at school are needed to be improved in term of scientific approach and inquiry learning model. The result of these analyses might be of interest in order to write future potential textbooks.

Novel nuclei isolation buffer for flow cytometric genome size estimation of Zingiberaceae: a comparison with common isolation buffers.

Science.gov (United States)

Sadhu, Abhishek; Bhadra, Sreetama; Bandyopadhyay, Maumita

2016-11-01

Cytological parameters such as chromosome numbers and genome sizes of plants are used routinely for studying evolutionary aspects of polyploid plants. Members of Zingiberaceae show a wide range of inter- and intrageneric variation in their reproductive habits and ploidy levels. Conventional cytological study in this group of plants is severely hampered by the presence of diverse secondary metabolites, which also affect their genome size estimation using flow cytometry. None of the several nuclei isolation buffers used in flow cytometry could be used very successfully for members of Zingiberaceae to isolate good quality nuclei from both shoot and root tissues. The competency of eight nuclei isolation buffers was compared with a newly formulated buffer, MB01, in six different genera of Zingiberaceae based on the fluorescence intensity of propidium iodide-stained nuclei using flow cytometric parameters, namely coefficient of variation of the G 0 /G 1 peak, debris factor and nuclei yield factor. Isolated nuclei were studied using fluorescence microscopy and bio-scanning electron microscopy to analyse stain-nuclei interaction and nuclei topology, respectively. Genome contents of 21 species belonging to these six genera were determined using MB01. Flow cytometric parameters showed significant differences among the analysed buffers. MB01 exhibited the best combination of analysed parameters; photomicrographs obtained from fluorescence and electron microscopy supported the superiority of MB01 buffer over other buffers. Among the 21 species studied, nuclear DNA contents of 14 species are reported for the first time. Results of the present study substantiate the enhanced efficacy of MB01, compared to other buffers tested, in the generation of acceptable cytograms from all species of Zingiberaceae studied. Our study facilitates new ways of sample preparation for further flow cytometric analysis of genome size of other members belonging to this highly complex polyploid family

The stochastic nuclide transport model for buffer/backfill materials

International Nuclear Information System (INIS)

Ma Liping; Han Yongguo

2014-01-01

Currently, study on nuclide migration law in geological disposal repository of high level waste is assumed buffer/backfill layer to be continuous medium, utilized the continuity equation, equation of state, the equations of motion, etc, formed a set of theory and method to estimate nuclide concentration distribution in buffer/backfill layer, and provided an important basis for nuclide migration rules of repository. However, it is necessary to study the buffer/backfill layer microstructure and subtly describe the pore structure and fracture system of the buffer/backfill layer, and reflect the changes in connectivity and in different directions of the buffer/backfill layer. Through using random field theory, the nuclide transport for the buffer/backfill layer in geological disposal repository of nuclear waste is described in the paper. This paper mainly includes that, t represents the time, ξ t ⊂ Z d = d represents the integer lattice, Z represents collectivity integers, d = l, 2, 3, for instance, d = 2, Z d = {(m, n) : m, n ∈ Z} the state point of ξ t is typically considered to be occupied by the nuclide concentration values of the buffer/backfill layer, ξ t also represents random set in the diagram of two dimensional integer lattice, namely, t ∈ [0, T], {ξ t ,0 ≤ t ≤ ⊂ T} Consequently, according to the stochastic process obtained above, the changes of the nuclide concentration values of the buffer/backfill layer or the buffer/backfill laboratory materials in the repository with the time can be known. (authors)

Buffer Zone, Nicosia

OpenAIRE

Sorensen, Marie Louise

2010-01-01

Images of the United Nations Buffer Zone or Green Line which has partitioned Cyprus since 1974 The research leading to these results has received funding from the European Community's Seventh Framework Programme [FP7/2007-2013] under grant agreement n° 217411.

Grass buffers for playas in agricultural landscapes: An annotated bibliography

Science.gov (United States)

Melcher, Cynthia P.; Skagen, Susan K.

2005-01-01

This bibliography and associated literature synthesis (Melcher and Skagen, 2005) was developed for the Playa Lakes Joint Venture (PLJV). The PLJV sought compilation and annotation of the literature on grass buffers for protecting playas from runoff containing sediments, nutrients, pesticides, and other contaminants. In addition, PLJV sought information regarding the extent to which buffers may attenuate the precipitation runoff needed to fill playas, and avian use of buffers. We emphasize grass buffers, but we also provide information on other buffer types.

Spectrographic analysis of waste waters; Analisis espectrografico de aguas residuales

Energy Technology Data Exchange (ETDEWEB)

Alvarez Alduan, F; Capdevila, C

1979-07-01

The Influence of sodium and calcium, up to a maximum concentration of 1000 mg/1 Na and 300 mg/1 Ca, in the spectrographic determination of Cr, Cu, Fe,Mn and Pb in waste waters using graphite spark excitation has been studied. In order to eliminate this influence, each of the elements Ba, Cs, In, La, Li, Sr and Ti, as well as a mixture containing 5% Li-50% Ti, have been tested as spectrochemical buffers. This mixture allows to obtain an accuracy better than 25%. Sodium and calcium enhance the line intensities of impurities, when using graphite or gold electrodes, but they produce an opposite effect if copper or silver electrodes are used. (Author) 1 refs.

Spectrographic analysis of waste waters

International Nuclear Information System (INIS)

Alvarez Alduan, F.; Capdevila, C.

1979-01-01

The Influence of sodium and calcium, up to a maximum concentration of 1000 mg/1 Na and 300 mg/1 Ca, in the spectrographic determination of Cr, Cu, Fe,Mn and Pb in waste waters using graphite spark excitation has been studied. In order to eliminate this influence, each of the elements Ba, Cs, In, La, Li, Sr and Ti, as well as a mixture containing 5% Li-50% Ti, have been tested as spectrochemical buffers. This mixture allows to obtain an accuracy better than 25%. Sodium and calcium enhance the line intensities of impurities, when using graphite or gold electrodes, but they produce an opposite effect if copper or silver electrodes are used. (Author) 1 refs

Thermo-Hydraulic Modelling of Buffer and Backfill

International Nuclear Information System (INIS)

Pintado, X.; Rautioaho, E.

2013-09-01

The temporal evolution of saturation, liquid pressure and temperature in the components of the engineered barrier system was studied using numerical methods. A set of laboratory tests was conducted to calibrate the parameters employed in the models. The modelling consisted of thermal, hydraulic and thermo-hydraulic analysis in which the significant thermo-hydraulic processes, parameters and features were identified. CODE B RIGHT was used for the finite element modelling and supplementary calculations were conducted with analytical methods. The main objective in this report is to improve understanding of the thermo-hydraulic processes and material properties that affect buffer behaviour in the Olkiluoto repository and to determine the parametric requirements of models for the accurate prediction of this behaviour. The analyses consisted of evaluating the influence of initial canister temperature and gaps in the buffer, and the role played by fractures and the rock mass located between fractures in supplying water for buffer and backfill saturation. In the thermo-hydraulic analysis, the primary processes examined were the effects of buffer drying near the canister on temperature evolution and the manner in which heat flow affects the buffer saturation process. Uncertainties in parameters and variations in the boundary conditions, modelling geometry and thermo-hydraulic phenomena were assessed with a sensitivity analysis. The material parameters, constitutive models, and assumptions made were carefully selected for all the modelling cases. The reference parameters selected for the simulations were compared and evaluated against laboratory measurements. The modelling results highlight the importance of understanding groundwater flow through the rock mass and from fractures in the rock in order to achieve reliable predictions regarding buffer saturation, since saturation times could range from a few years to tens of thousands of years depending on the hydrogeological

The buffer value of groundwater when well yield is limited

Science.gov (United States)

Foster, T.; Brozović, N.; Speir, C.

2017-04-01

A large proportion of the total value of groundwater in conjunctive use systems is associated with the ability to smooth out shortfalls in surface water supply during droughts. Previous research has argued that aquifer depletion in these regions will impact farmers negatively by reducing the available stock of groundwater to buffer production in future periods, and also by increasing the costs of groundwater extraction. However, existing studies have not considered how depletion may impact the productivity of groundwater stocks in conjunctive use systems through reductions in well yields. In this work, we develop a hydro-economic modeling framework to quantify the effects of changes in well yields on the buffer value of groundwater, and apply this model to an illustrative case study of tomato production in California's Central Valley. Our findings demonstrate that farmers with low well yields are forced to forgo significant production and profits because instantaneous groundwater supply is insufficient to buffer surface water shortfalls in drought years. Negative economic impacts of low well yields are an increasing function of surface water variability, and are also greatest for farmers operating less efficient irrigation systems. These results indicate that impacts of well yield reductions on the productivity of groundwater are an important economic impact of aquifer depletion, and that failure to consider this feedback may lead to significant errors in estimates of the value of groundwater management in conjunctive use systems.

The buffer/container experiment design and construction report

Energy Technology Data Exchange (ETDEWEB)

Chandler, N.A.; Wan, A.W.L.; Roach, P.J

1998-03-01

The Buffer/Container Experiment was a full-scale in situ experiment, installed at a depth of 240 m in granitic rock at AECL's Underground Research Laboratory (URL). The experiment was designed to examine the performance of a compacted sand-bentonite buffer material under the influences of elevated temperature and in situ moisture conditions. Buffer material was compacted in situ into a 5-m-deep, 1.24-m-diameter borehole drilled into the floor of an excavation. A 2.3-m long heater, representative of a nuclear fuel waste container, was placed within the buffer, and instrumentation was installed to monitor changes in buffer moisture conditions, temperature and stress. The experiment was sealed at the top of the borehole and restrained against vertical displacement. Instrumentation in the rock monitored pore pressures, temperatures and rock displacement. The heater was operated at a constant power of 1200 W, which provided a heater skin temperature of approximately 85 degrees C. Experiment construction and installation required two years, followed by two and a half years of heater operation and two years of monitoring the rock conditions during cooling. The construction phase of the experiment included the design, construction and testing of a segmental heater and controller, geological and hydrogeological characterization of the rock, excavation of the experiment room, drilling of the emplacement borehole using high pressure water, mixing and in situ compaction of buffer material, installation of instrumentation in the rock, buffer and on the heater, and the construction of concrete curb and steel vertical restraint system at the top of emplacement borehole. Upon completion of the experiment, decommissioning sampling equipment was designed and constructed and sampling methods were developed which allowed approximately 2000 samples of buffer material to be taken over a 12-day period. Quality assurance procedures were developed for all aspects of experiment

The buffer/container experiment design and construction report

International Nuclear Information System (INIS)

Chandler, N.A.; Wan, A.W.L.; Roach, P.J.

1998-03-01

The Buffer/Container Experiment was a full-scale in situ experiment, installed at a depth of 240 m in granitic rock at AECL's Underground Research Laboratory (URL). The experiment was designed to examine the performance of a compacted sand-bentonite buffer material under the influences of elevated temperature and in situ moisture conditions. Buffer material was compacted in situ into a 5-m-deep, 1.24-m-diameter borehole drilled into the floor of an excavation. A 2.3-m long heater, representative of a nuclear fuel waste container, was placed within the buffer, and instrumentation was installed to monitor changes in buffer moisture conditions, temperature and stress. The experiment was sealed at the top of the borehole and restrained against vertical displacement. Instrumentation in the rock monitored pore pressures, temperatures and rock displacement. The heater was operated at a constant power of 1200 W, which provided a heater skin temperature of approximately 85 degrees C. Experiment construction and installation required two years, followed by two and a half years of heater operation and two years of monitoring the rock conditions during cooling. The construction phase of the experiment included the design, construction and testing of a segmental heater and controller, geological and hydrogeological characterization of the rock, excavation of the experiment room, drilling of the emplacement borehole using high pressure water, mixing and in situ compaction of buffer material, installation of instrumentation in the rock, buffer and on the heater, and the construction of concrete curb and steel vertical restraint system at the top of emplacement borehole. Upon completion of the experiment, decommissioning sampling equipment was designed and constructed and sampling methods were developed which allowed approximately 2000 samples of buffer material to be taken over a 12-day period. Quality assurance procedures were developed for all aspects of experiment construction

Further improvements in competitive guarantees for QoS buffering

NARCIS (Netherlands)

Bansal, N.; Fleischer, L.K.; Kimbrel, T.; Mahdian, M.; Schieber, B.; Sviridenko, M.; Diaz, J.; Karhumäki, J.; Lepistö, A.; Sannella, D.

2004-01-01

We study the behavior of algorithms for buffering packets weighted by different levels of Quality of Service (QoS) guarantees in a single queue. Buffer space is limited, and packet loss occurs when the buffer overflows. We describe a modification of the previously proposed ``preemptive greedy{''}

Predicting the safety and efficacy of buffer therapy to raise tumour pHe: an integrative modelling study

Science.gov (United States)

Martin, N K; Robey, I F; Gaffney, E A; Gillies, R J; Gatenby, R A; Maini, P K

2012-01-01

Background: Clinical positron emission tomography imaging has demonstrated the vast majority of human cancers exhibit significantly increased glucose metabolism when compared with adjacent normal tissue, resulting in an acidic tumour microenvironment. Recent studies demonstrated reducing this acidity through systemic buffers significantly inhibits development and growth of metastases in mouse xenografts. Methods: We apply and extend a previously developed mathematical model of blood and tumour buffering to examine the impact of oral administration of bicarbonate buffer in mice, and the potential impact in humans. We recapitulate the experimentally observed tumour pHe effect of buffer therapy, testing a model prediction in vivo in mice. We parameterise the model to humans to determine the translational safety and efficacy, and predict patient subgroups who could have enhanced treatment response, and the most promising combination or alternative buffer therapies. Results: The model predicts a previously unseen potentially dangerous elevation in blood pHe resulting from bicarbonate therapy in mice, which is confirmed by our in vivo experiments. Simulations predict limited efficacy of bicarbonate, especially in humans with more aggressive cancers. We predict buffer therapy would be most effectual: in elderly patients or individuals with renal impairments; in combination with proton production inhibitors (such as dichloroacetate), renal glomular filtration rate inhibitors (such as non-steroidal anti-inflammatory drugs and angiotensin-converting enzyme inhibitors), or with an alternative buffer reagent possessing an optimal pK of 7.1–7.2. Conclusion: Our mathematical model confirms bicarbonate acts as an effective agent to raise tumour pHe, but potentially induces metabolic alkalosis at the high doses necessary for tumour pHe normalisation. We predict use in elderly patients or in combination with proton production inhibitors or buffers with a pK of 7.1–7.2 is most

Predicting the safety and efficacy of buffer therapy to raise tumour pHe: an integrative modelling study.

Science.gov (United States)

Martin, N K; Robey, I F; Gaffney, E A; Gillies, R J; Gatenby, R A; Maini, P K

2012-03-27

Clinical positron emission tomography imaging has demonstrated the vast majority of human cancers exhibit significantly increased glucose metabolism when compared with adjacent normal tissue, resulting in an acidic tumour microenvironment. Recent studies demonstrated reducing this acidity through systemic buffers significantly inhibits development and growth of metastases in mouse xenografts. We apply and extend a previously developed mathematical model of blood and tumour buffering to examine the impact of oral administration of bicarbonate buffer in mice, and the potential impact in humans. We recapitulate the experimentally observed tumour pHe effect of buffer therapy, testing a model prediction in vivo in mice. We parameterise the model to humans to determine the translational safety and efficacy, and predict patient subgroups who could have enhanced treatment response, and the most promising combination or alternative buffer therapies. The model predicts a previously unseen potentially dangerous elevation in blood pHe resulting from bicarbonate therapy in mice, which is confirmed by our in vivo experiments. Simulations predict limited efficacy of bicarbonate, especially in humans with more aggressive cancers. We predict buffer therapy would be most effectual: in elderly patients or individuals with renal impairments; in combination with proton production inhibitors (such as dichloroacetate), renal glomular filtration rate inhibitors (such as non-steroidal anti-inflammatory drugs and angiotensin-converting enzyme inhibitors), or with an alternative buffer reagent possessing an optimal pK of 7.1-7.2. Our mathematical model confirms bicarbonate acts as an effective agent to raise tumour pHe, but potentially induces metabolic alkalosis at the high doses necessary for tumour pHe normalisation. We predict use in elderly patients or in combination with proton production inhibitors or buffers with a pK of 7.1-7.2 is most promising.

Buffers Plus

Science.gov (United States)

Ramette, Richard W.

1998-11-01

In 1989 JCE Software published The Acid-Base Package: A Collection of Useful Programs for Proton Transfer Systems (Ramette, R. W. J. Chem. Educ. Software 1989, 2B No. 2). This DOS program has been fully upgraded by the same author to the world of Windows 95. Buffers Plus takes advantage of a modern user interface and offers many new options not possible in the original version.

Stacking and discontinuous buffers in capillary zone electrophoresis.

Science.gov (United States)

Shihabi, Z K

2000-08-01

Discontinuous buffers for capillary zone electrophoresis (CZE) can be used under less rigid conditions compared to those for isotachophoresis for stacking. They can be prepared simply by modifying the sample itself, either by addition of small inorganic ions, low conductivity diluents, or both, and also by adjusting its pH, meanwhile injecting a large volume on the capillary. Zwitterionic and organic-based buffers such as triethanolamine and tris(hydroxymethyl)aminomethane (Tris) are well suited for stacking due to their low conductivity, provided the buffer is discontinuous as demonstrated here. A simple mechanism based on discontinuous buffers is described to explain many of the observed stacking types in CZE, pointing out the many similarities to transient isotachophoresis.

Improved indexes for targeting placement of buffers of Hortonian runoff

Science.gov (United States)

M.G. Dosskey; Z. Qiu; M.J. Helmers; D.E. Eisenhauer

2011-01-01

Targeting specific locations within agricultural watersheds for installing vegetative buffers has been advocated as a way to enhance the impact of buffers and buffer programs on stream water quality. Existing models for targeting buffers of Hortonian, or infiltration-excess, runoff are not well developed. The objective was to improve on an existing soil survey–based...

Strontium Titanate Buffer Layers on Cu/33%Ni Substrates using a Novel Solution Chemistry

DEFF Research Database (Denmark)

Pallewatta, Pallewatta G A P; Yue, Zhao; Hui, Tian

2013-01-01

SrTiO3 is a widely studied perovskite material due to its advantages as a buffer template which can be simply applied between a metal substrate tape and a superconducting layer in 2G high temperature superconducting (HTS) tapes. In this study, heteroepitaxial SrTiO3 thin films were deposited on t...

Effects of buffer thickness on ATW blanket performances

International Nuclear Information System (INIS)

Yang, Won Sik

2001-01-01

This paper presents the preliminary results of target and buffer design studies for a lead-bismuth eutectic (LBE) cooled accelerator transmutation of waste (ATW) system, aimed at maximizing the source importance while simultaneously reducing the irradiation damage to fuel. Using an 840 MWt LBE cooled ATW design, the effects of buffer thickness on the blanket performances have been studied. Varying the buffer thickness for a given blanket configuration, system performances have been estimated by a series of calculations using MCNPX and REBUS-3 codes. The effects of source importance change are studied by investigating the low-energy (< 20 MeV) neutron source distribution and the equilibrium cycle blanket performance parameters such as fuel inventory, discharge burnup, burnup reactivity loss, and peak fast fluence. As the irradiation damage to fuel, the displacements per atom (dpa), hydrogen production, and helium production rates are evaluated at the buffer and blanket interface where the peak fast fluence occurs. The results show that the damage rates and the source importance increase monotonically as the buffer thickness decreases. Based on a compromise between the competing objectives of increasing the source importance and reducing the damage rates, a buffer thickness of around 20 cm appears to be reasonable

Scientific Applications Performance Evaluation on Burst Buffer

KAUST Repository

Markomanolis, George S.

2017-10-19

Parallel I/O is an integral component of modern high performance computing, especially in storing and processing very large datasets, such as the case of seismic imaging, CFD, combustion and weather modeling. The storage hierarchy includes nowadays additional layers, the latest being the usage of SSD-based storage as a Burst Buffer for I/O acceleration. We present an in-depth analysis on how to use Burst Buffer for specific cases and how the internal MPI I/O aggregators operate according to the options that the user provides during his job submission. We analyze the performance of a range of I/O intensive scientific applications, at various scales on a large installation of Lustre parallel file system compared to an SSD-based Burst Buffer. Our results show a performance improvement over Lustre when using Burst Buffer. Moreover, we show results from a data hierarchy library which indicate that the standard I/O approaches are not enough to get the expected performance from this technology. The performance gain on the total execution time of the studied applications is between 1.16 and 3 times compared to Lustre. One of the test cases achieved an impressive I/O throughput of 900 GB/s on Burst Buffer.

In vitro dissolution of proton-pump inhibitor products intended for paediatric and geriatric use in physiological bicarbonate buffer.

Science.gov (United States)

Liu, Fang; Shokrollahi, Honaz

2015-05-15

Proton-pump inhibitor (PPI) products based on enteric coated multiparticulates are design to meet the needs of patients who cannot swallow tablets such as children and older adults. Enteric coated PPI preparations exhibit delays in in vivo absorption and onset of antisecretory effects, which is not reflected by the rapid in vitro dissolution in compendial pH 6.8 phosphate buffer commonly used for assessment of these products. A more representative and physiological medium, pH 6.8 mHanks bicarbonate buffer, was used in this study to evaluate the in vitro dissolution of enteric coated multiparticulate-based PPI products. Commercially available omeprazole, lansoprazole and esomeprazole products were subject to dissolution tests using USP-II apparatus in pH 4.5 phosphate buffer saline for 45 min (acid stage) followed by pH 6.8 phosphate buffer or pH 6.8 mHanks bicarbonate buffer. In pH 6.8 phosphate buffer, all nine tested products displayed rapid and comparable dissolution profiles meeting the pharmacopeia requirements for delayed release preparations. In pH 6.8 mHanks buffer, drug release was delayed and failed the pharmacopeia requirements from most enteric coated preparations. Despite that the same enteric polymer, methacrylic acid-ethyl acrylate copolymer (1:1), was applied to all commercial multiparticulate-based products, marked differences were observed between dissolution profiles of these preparations. The use of pH 6.8 physiological bicarbonate (mHanks) buffer can serve as a useful tool to provide realistic and discriminative in vitro release assessment of enteric coated PPI preparations and to assist rational formulation development of these products. Copyright © 2015 Elsevier B.V. All rights reserved.

ACETIC ACID AND A BUFFER

DEFF Research Database (Denmark)

2009-01-01

The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

Temperature buffer test. Installation of buffer, heaters and instruments in the deposition hole

Energy Technology Data Exchange (ETDEWEB)

Johannesson, Lars-Erik; Sanden, Torbjoern; Aakesson, Mattias [Clay Technology AB, Lund (Sweden); Barcena, Ignacio; Garcia-Sineriz, Jose Luis [Aitemin, Madrid (Spain)

2010-12-15

During 2003 the Temperature Buffer Test was installed in Aespoe Hard Rock Laboratory. Temperature, water pressure, relative humidity, total pressure and displacements etc. are measured in numerous points in the test. Most of the cables from the transducers are led in the deposition hole through slots in the rock surface of the deposition hole in watertight tubes to the data collection system in a container placed in the tunnel close to the deposition hole. This report describes the work with the installations of the buffer, heaters, and instruments and yields a description of the final location of all instruments. The report also contains a description of the materials that were installed and the densities yielded after placement.

Temperature buffer test. Installation of buffer, heaters and instruments in the deposition hole

International Nuclear Information System (INIS)

Johannesson, Lars-Erik; Sanden, Torbjoern; Aakesson, Mattias; Barcena, Ignacio; Garcia-Sineriz, Jose Luis

2010-12-01

During 2003 the Temperature Buffer Test was installed in Aespoe Hard Rock Laboratory. Temperature, water pressure, relative humidity, total pressure and displacements etc. are measured in numerous points in the test. Most of the cables from the transducers are led in the deposition hole through slots in the rock surface of the deposition hole in watertight tubes to the data collection system in a container placed in the tunnel close to the deposition hole. This report describes the work with the installations of the buffer, heaters, and instruments and yields a description of the final location of all instruments. The report also contains a description of the materials that were installed and the densities yielded after placement

Surface runoff water quality in a managed three zone riparian buffer.

Science.gov (United States)

Lowrance, Richard; Sheridan, Joseph M

2005-01-01

Managed riparian forest buffers are an important conservation practice but there are little data on the water quality effects of buffer management. We measured surface runoff volumes and nutrient concentrations and loads in a riparian buffer system consisting of (moving down slope from the field) a grass strip, a managed forest, and an unmanaged forest. The managed forest consisted of sections of clear-cut, thinned, and mature forest. The mature forest had significantly lower flow-weighted concentrations of nitrate, ammonium, total Kjeldahl N (TKN), sediment TKN, total N (nitrate + TKN), dissolved molybdate reactive P (DMRP), total P, and chloride. The average buffer represented the conditions along a stream reach with a buffer system in different stages of growth. Compared with the field output, flow-weighted concentrations of nitrate, ammonium, DMRP, and total P decreased significantly within the buffer and flow-weighted concentrations of TKN, total N, and chloride increased significantly within the buffer. All loads decreased significantly from the field to the middle of the buffer, but most loads increased from the middle of the buffer to the sampling point nearest the stream because surface runoff volume increased near the stream. The largest percentage reduction of the incoming nutrient load (at least 65% for all nutrient forms) took place in the grass buffer zone because of the large decrease (68%) in flow. The average buffer reduced loadings for all nutrient species, from 27% for TKN to 63% for sediment P. The managed forest and grass buffer combined was an effective buffer system.

Buffer construction technique using granular bentonite

International Nuclear Information System (INIS)

Masuda, Ryoichi; Asano, Hidekazu; Toguri, Satohito; Mori, Takuo; Shimura, Tomoyuki; Matsuda, Takeshi; Uyama, Masao; Noda, Masaru

2007-01-01

Buffer construction using bentonite pellets as filling material is a promising technology for enhancing the ease of repository operation. In this study, a test of such technology was conducted in a full-scale simulated disposal drift, using a filling system which utilizes a screw conveyor system. The simulated drift, which contained two dummy overpacks, was configured as a half-cross-section model with a height of 2.22 m and a length of 6.0 m. The average dry density of the buffer obtained in the test was 1.29 Mg/m 3 , with an angle of repose of 35 to 40 degrees. These test results indicate that buffer construction using a screw conveyor system for pellet emplacement in a waste disposal drift is a promising technology for repositories for high level radioactive wastes. (author)

Dynamic Buffer Capacity in Acid-Base Systems.

Science.gov (United States)

Michałowska-Kaczmarczyk, Anna M; Michałowski, Tadeusz

The generalized concept of 'dynamic' buffer capacity β V is related to electrolytic systems of different complexity where acid-base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton-Robinson buffers, taken as examples.

Dynamic Buffer Capacity in Acid?Base Systems

OpenAIRE

Micha?owska-Kaczmarczyk, Anna M.; Micha?owski, Tadeusz

2015-01-01

The generalized concept of ?dynamic? buffer capacity ? V is related to electrolytic systems of different complexity where acid?base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton?Robinson buffers, taken as examples.

Buffered Simulation Games for Büchi Automata

Directory of Open Access Journals (Sweden)

Milka Hutagalung

2014-05-01

Full Text Available Simulation relations are an important tool in automata theory because they provide efficiently computable approximations to language inclusion. In recent years, extensions of ordinary simulations have been studied, for instance multi-pebble and multi-letter simulations which yield better approximations and are still polynomial-time computable. In this paper we study the limitations of approximating language inclusion in this way: we introduce a natural extension of multi-letter simulations called buffered simulations. They are based on a simulation game in which the two players share a FIFO buffer of unbounded size. We consider two variants of these buffered games called continuous and look-ahead simulation which differ in how elements can be removed from the FIFO buffer. We show that look-ahead simulation, the simpler one, is already PSPACE-hard, i.e. computationally as hard as language inclusion itself. Continuous simulation is even EXPTIME-hard. We also provide matching upper bounds for solving these games with infinite state spaces.

Moisture Buffer Effect and its Impact on Indoor Environment

DEFF Research Database (Denmark)

Zhang, Mingjie; Qin, Menghao; Chen, Zhi

2017-01-01

The moisture buffer effect of building materials may have great influence on indoor hygrothermal environment. In order to characterize the moisture buffering ability of materials, the basic concept of moisture buffer value (MBV) is adopted. Firstly, a theoretical correction factor is introduced...... in this paper. The moisture uptake/release by hygroscopic materials can be calculated with the factor and the basic MBV. Furthermore, the validation of the correction factor is carried out. The impact of moisture buffering on indoor environment is assessed by using numerical simulations. The results show...

Effects of node buffer and capacity on network traffic

International Nuclear Information System (INIS)

Ling Xiang; Ding Jian-Xun; Hu Mao-Bin

2012-01-01

In this paper, we study the optimization of network traffic by considering the effects of node buffer ability and capacity. Two node buffer settings are considered. The node capacity is considered to be proportional to its buffer ability. The node effects on network traffic systems are studied with the shortest path protocol and an extension of the optimal routing [Phys. Rev. E 74 046106 (2006)]. In the diagrams of flux—density relationships, it is shown that a nodes buffer ability and capacity have profound effects on the network traffic

Back contact buffer layer for thin-film solar cells

Science.gov (United States)

Compaan, Alvin D.; Plotnikov, Victor V.

2014-09-09

A photovoltaic cell structure is disclosed that includes a buffer/passivation layer at a CdTe/Back contact interface. The buffer/passivation layer is formed from the same material that forms the n-type semiconductor active layer. In one embodiment, the buffer layer and the n-type semiconductor active layer are formed from cadmium sulfide (CdS). A method of forming a photovoltaic cell includes the step of forming the semiconductor active layers and the buffer/passivation layer within the same deposition chamber and using the same material source.

Solubilization of proteins: the importance of lysis buffer choice.

Science.gov (United States)

Peach, Mandy; Marsh, Noelle; Miskiewicz, Ewa I; MacPhee, Daniel J

2015-01-01

The efficient extraction of proteins of interest from cells and tissues is not always straightforward. Here we demonstrate the differences in extraction of the focal adhesion protein Kindlin-2 from choriocarcinoma cells using NP-40 and RIPA lysis buffer. Furthermore, we demonstrate the use of a more denaturing urea/thiourea lysis buffer for solubilization, by comparing its effectiveness for solubilization of small heat-shock proteins from smooth muscle with the often utilized RIPA lysis buffer. Overall, the results demonstrate the importance of establishing the optimal lysis buffer for specific protein solubilization within the experimental workflow.

Effect of Buffer Bow Structure in Ship-Ship Collision

DEFF Research Database (Denmark)

Yamada, Yasuhira; Endo, Hisayoshi; Pedersen, Preben Terndrup

2008-01-01

tankers, the introduction of buffer bulbous bows has been proposed. Relatively soft buffer bows absorb part of the kinetic energy of the striking ship before penetrating the inner hull of the struck vessel. The purpose of the present paper is to verify the effectiveness of a prototype buffer bulbous bow......) and the forward velocity of the struck ship on the collapse mode of the bow of the striking vessel are investigated. Collapse modes, contact forces and energy absorption capabilities of the buffer bows are compared with those of conventional bows....

Width of riparian buffer and structure of adjacent plantations influence occupancy of conservation priority birds

Science.gov (United States)

Roger W. Perry; T. Bently Wigley; M. Anthony Melchiors; Ronald E. Thill; Philip A. Tappe; Darren A. Miller

2011-01-01

Conservation of biodiversity on forest landscapes dominated by plantations has become an increasingly important topic, and opportunities to maintain or enhance biodiversity within these forests need to be recognized and applied. Riparian buffers of mature forest retained along streams in managed forest landscapes offer an opportunity to enhance biodiversity across...

The quantitation of buffering action II. Applications of the formal & general approach

Science.gov (United States)

Schmitt, Bernhard M

2005-01-01

Background The paradigm of "buffering" originated in acid-base physiology, but was subsequently extended to other fields and is now used for a wide and diverse set of phenomena. In the preceding article, we have presented a formal and general approach to the quantitation of buffering action. Here, we use that buffering concept for a systematic treatment of selected classical and other buffering phenomena. Results H+ buffering by weak acids and "self-buffering" in pure water represent "conservative buffered systems" whose analysis reveals buffering properties that contrast in important aspects from classical textbook descriptions. The buffering of organ perfusion in the face of variable perfusion pressure (also termed "autoregulation") can be treated in terms of "non-conservative buffered systems", the general form of the concept. For the analysis of cytoplasmic Ca++ concentration transients (also termed "muffling"), we develop a related unit that is able to faithfully reflect the time-dependent quantitative aspect of buffering during the pre-steady state period. Steady-state buffering is shown to represent the limiting case of time-dependent muffling, namely for infinitely long time intervals and infinitely small perturbations. Finally, our buffering concept provides a stringent definition of "buffering" on the level of systems and control theory, resulting in four absolute ratio scales for control performance that are suited to measure disturbance rejection and setpoint tracking, and both their static and dynamic aspects. Conclusion Our concept of buffering provides a powerful mathematical tool for the quantitation of buffering action in all its appearances. PMID:15771784

Molding method of buffer material for underground disposal of radiation-contaminated material, and molded buffer material

International Nuclear Information System (INIS)

Akasaka, Hidenari; Shimura, Satoshi; Kawakami, Susumu; Ninomiya, Nobuo; Yamagata, Junji; Asano, Eiichi

1995-01-01

Upon molding of a buffer material to be used upon burying a vessel containing radiation-contaminated materials in a sealed state, a powdery buffer material to be molded such as bentonite is disposed at the periphery of a mandrel having a cylindrical portion somewhat larger than contaminate container to be subjected to underground disposal. In addition, it is subjected to integration-molding such as cold isotropic press with a plastic film being disposed therearound, to form a molding product at high density. The molding product is released and taken out with the plastic film being disposed thereon. Releasability from an elastic mold is improved by the presence of the plastic film. In addition, if it is stored or transported while having the plastic film being disposed thereon, swelling of the buffer material due to water absorption or moisture absorption can be suppressed. (T.M.)

Buffering capacity: its relevance in soil and water pollution

Energy Technology Data Exchange (ETDEWEB)

Stigliani, W.M. [University of Northern Iowa, Cedar Falls (United States)

1996-02-01

Buffering capacities in soils are essential for neutralizing or immobilizing inputs of acids and heavy metals. There are four major buffering regimes, each of which operates in a defined pH range. When the rate of pollutant inputs exceeds the rate of natural replenishment of the buffer in a specific regime, the supply of buffer will be exhausted over time, and the soil may switch to a regime at lower pH. As the pH of the soil declines, so does its capacity to immobilize heavy metals. If the soil initially has a moderately high buffering capacity, the time scale before exhaustion is on the order of decades to a century. Over this time there may be no observable environmental effects. When the effects do become obvious, it may be too late to reverse the damage. The importance of buffering capacity as a valued environmental resource must be recognized, and its preservation must be a major component of long-term soil protection policies. (Author). 17 refs., 6 figs., 1 tab.

Sensitivity of total stress to changes in externally applied water pressure in KBS-3 buffer bentonite

Energy Technology Data Exchange (ETDEWEB)

Harrington, J.F.; Birchall, D.J. [British Geological Survey, Chemical and Biological Hazards Programme, Kingsley Dunham Centre (United Kingdom)

2007-04-15

In the current Swedish repository design concept, composite copper and steel canisters containing spent nuclear fuel will be placed in large diameter disposal boreholes drilled into the floor of the repository tunnels. The space around each canister will be filled with pre-compacted bentonite which over time will draw in the surrounding ground water and swell, closing up any construction joints. However, for the purposes of performance assessment, it is necessary to consider the effect of glacial loading of a future repository and its impact on the mechanical behaviour of the bentonite, in particular, the sensitivity of total stress to changes in porewater pressure (backpressure). Two experimental histories have been undertaken using a custom-designed constant volume and radial flow (CVRF) apparatus. In both tests backpressure was varied in a number of incremental and decremental cycles while total stress, porewater pressure and volumetric flow rate were continuously monitored. The swelling pressure of the buffer clay at dry densities of 1.8 Mg/m{sup 3} and 1.61 Mg/m{sup 3} was determined to be around 5.5 MPa and 7.2 MPa respectively. For initial ascending porewater pressure histories the average proportionality factor {alpha} ranged from 0.86 and 0.92. Data exhibited a general trend of increasing {alpha} with increasing backpressure. In test Mx80-11 this was supported by analysis of the water inflow data which indicated a reduction in system compressibility. Asymptotic values of porewater pressure within the clay are in good agreement with externally applied backpressure values. Inspection of data provides no evidence for the development of hydraulic thresholds within the clay, subject to the boundary conditions of this test geometry. Analysis of the stress data demonstrates significant hysteresis between ascending and descending porewater pressure histories. The amount of hysteresis appears to be linked to the magnitude of the backpressure applied to the specimen

Sensitivity of total stress to changes in externally applied water pressure in KBS-3 buffer bentonite

International Nuclear Information System (INIS)

Harrington, J.F.; Birchall, D.J.

2007-04-01

In the current Swedish repository design concept, composite copper and steel canisters containing spent nuclear fuel will be placed in large diameter disposal boreholes drilled into the floor of the repository tunnels. The space around each canister will be filled with pre-compacted bentonite which over time will draw in the surrounding ground water and swell, closing up any construction joints. However, for the purposes of performance assessment, it is necessary to consider the effect of glacial loading of a future repository and its impact on the mechanical behaviour of the bentonite, in particular, the sensitivity of total stress to changes in porewater pressure (backpressure). Two experimental histories have been undertaken using a custom-designed constant volume and radial flow (CVRF) apparatus. In both tests backpressure was varied in a number of incremental and decremental cycles while total stress, porewater pressure and volumetric flow rate were continuously monitored. The swelling pressure of the buffer clay at dry densities of 1.8 Mg/m 3 and 1.61 Mg/m 3 was determined to be around 5.5 MPa and 7.2 MPa respectively. For initial ascending porewater pressure histories the average proportionality factor α ranged from 0.86 and 0.92. Data exhibited a general trend of increasing α with increasing backpressure. In test Mx80-11 this was supported by analysis of the water inflow data which indicated a reduction in system compressibility. Asymptotic values of porewater pressure within the clay are in good agreement with externally applied backpressure values. Inspection of data provides no evidence for the development of hydraulic thresholds within the clay, subject to the boundary conditions of this test geometry. Analysis of the stress data demonstrates significant hysteresis between ascending and descending porewater pressure histories. The amount of hysteresis appears to be linked to the magnitude of the backpressure applied to the specimen, suggesting some

Emplacement of small and large buffer blocks

International Nuclear Information System (INIS)

Saari, H.; Nikula, M.; Suikki, M.

2010-05-01

The report describes emplacement of a buffer structure encircling a spent fuel canister to be deposited in a vertical hole. The report deals with installability of various size blocks and with an emplacement gear, as well as evaluates the achieved quality of emplacement and the time needed for installing the buffer. Two block assembly of unequal size were chosen for examination. A first option involved small blocks, the use of which resulted in a buffer structure consisting of small sector blocks 200 mm in height. A second option involved large blocks, resulting in a buffer structure which consists of eight blocks. In these tests, the material chosen for both block options was concrete instead of bentonite. The emplacement test was a three-phase process. A first phase included stacking a two meter high buffer structure with small blocks for ensuring the operation of test equipment and blocks. A second phase included installing buffer structures with both block options to a height matching that of a canister-encircling cylindrical component. A third phase included testing also the installability of blocks to be placed above the canister by using small blocks. In emplacement tests, special attention was paid to the installability of blocks as well as to the time required for emplacement. Lifters for both blocks worked well. Due to the mass to be lifted, the lifter for large blocks had a more heavy-duty frame structure (and other lifting gear). The employed lifters were suspended in the tests on a single steel wire rope. Stacking was managed with both block sizes at adequate precision and stacked-up towers were steady. The stacking of large blocks was considerably faster. Therefore it is probably that the overall handling of the large blocks will be more convenient at a final disposal site. From the standpoint of reliability in lifting, the small blocks were safer to install above the canister. In large blocks, there are strict shape-related requirements which are

Performance Enhancement of Small Molecular Solar Cells by Bilayer Cathode Buffer.

Science.gov (United States)

Sun, Qinjun; Zhao, Huanbin; Zhou, Miao; Gao, Liyan; Hao, Yuying

2016-04-01

An effective composite bilayer cathode buffer structure is proposed for use in small molecular solar cells. CsF was doped in Alq3 to form the first cathode buffer, leading to small serial resistances. BCP was used as the second cathode buffer to block the holes to the electrode. The optimized bilayer cathode buffer significantly increased the short circuit and fill factor of devices. By integrating this bilayer cathode buffer, the CuPc/C60 small molecular heterojunction cell exhibited a power conversion efficiency of up to 0.8%, which was an improvement of 56% compared to a device with only the Alq3 cathode buffer. Meanwhile, the bilayer cathode buffer still has a good protective effect on the performance of the device.

Current status of mechanical erosion studies of bentonite buffer

International Nuclear Information System (INIS)

Sane, P.; Olin, M.; Koskinen, K.

2013-08-01

The performance of the bentonite buffer in KBS-3-type nuclear waste repository concept relies to a great extent on the buffer surrounding the canister having sufficient dry density. Loss of buffer material caused by erosion remains as the most significant process reducing the density of the buffer. The mechanical erosion, or pre-saturation erosion, is the process where flowing groundwater transports buffer material away from the deposition hole towards the deposition tunnel. This process reduces the overall buffer density and potentially creates localized regions of low density. In the worst case the process is assumed to last as long as the free volume between the pellets in the pellets filled regions is filled with groundwater. With fixed environmental and material parameters a set of experiments was performed, testing the erosive properties of different buffer and backfill materials (MX-80 and Friedland Clay) in different groundwater conditions. The method used was a pinhole erosion test using two sizescales; 100 mm and 400 mm of cell length. The purpose of the pinhole tests was to test the scenario where piping channel is formed in the buffer and water flows through a single channel. The erosion data was produced with two methods, firstly the time-related erosion rates measured in-situ during the measurement and secondly the overall mass loss in the sample cell measured after dismantling of the test. It was observed that erosion in piping channels decreases rapidly (∼24 h) and irreversibly to a level that is an order of magnitude lower than the peak values. (orig.)

Effects of buffer thickness on ATW blanket performance

International Nuclear Information System (INIS)

Yang, W. S.; Mercatali, L.; Taiwo, T. A.; Hill, R. N.

2001-01-01

This paper presents preliminary results of target and buffer design studies for liquid metal cooled accelerator transmutation of waste (ATW) systems, aimed at maximizing the source importance while simultaneously reducing the irradiation damage to fuel. Using 840 MWt liquid metal cooled ATW designs, the effects of buffer thickness on the blanket performance have been studied. Varying the buffer thickness for a given blanket configuration, system performance parameters have been estimated by a series of calculations using the MCNPX and REBUS-3 codes. The effects of source importance variation are studied by investigating the low-energy ( and lt; 20 MeV) neutron source distribution and the equilibrium cycle blanket performance parameters such as fuel inventory, discharge burnup, burnup reactivity loss, and peak fast fluence. For investigating irradiation damage to fuel, the displacements per atom (dpa), hydrogen production, and helium production rates are evaluated at the buffer and blanket interface where the peak fast fluence occurs. Results for the liquid-metal-cooled designs show that the damage rates and the source importance increase monotonically as the buffer thickness decreases. Based on a compromise between the competing objectives of increasing the source importance and reducing the damage rates, a buffer thickness of around 20 cm appears to be reasonable. Investigation of the impact of the proton beam energy on the target and buffer design shows that for a given blanket power level, a lower beam energy (0.6 GeV versus 1 GeV) results in a higher irradiation damage to the beam window. This trend occurs because of the increase in the beam intensity required to maintain the power level

Effects of Buffer Thickness on ATW Blanket Performance

International Nuclear Information System (INIS)

Yang, W.S.; Mercatali, L.; Taiwo, T.A.; Hill, R.N.

2002-01-01

This paper presents preliminary results of target and buffer design studies for liquid metal cooled accelerator transmutation of waste (ATW) systems, aimed at maximizing the source importance while simultaneously reducing the irradiation damage to fuel. Using 840 MWt liquid metal cooled ATW designs, the effects of buffer thickness on the blanket performance have been studied. Varying the buffer thickness for a given blanket configuration, system performance parameters have been estimated by a series of calculations using the MCNPX and REBUS-3 codes. The effects of source importance variation are studied by investigating the low-energy (< 20 MeV) neutron source distribution and the equilibrium cycle blanket performance parameters such as fuel inventory, discharge burnup, burnup reactivity loss, and peak fast fluence. For investigating irradiation damage to fuel, the displacements per atom (dpa), hydrogen production, and helium production rates are evaluated at the buffer and blanket interface where the peak fast fluence occurs. Results for the liquid-metal-cooled designs show that the damage rates and the source importance increase monotonically as the buffer thickness decreases. Based on a compromise between the competing objectives of increasing the source importance and reducing the damage rates, a buffer thickness of around 20 cm appears to be reasonable. Investigation of the impact of the proton beam energy on the target and buffer design shows that for a given blanket power level, a lower beam energy (0.6 GeV versus 1 GeV) results in a higher irradiation damage to the beam window. This trend occurs because of the increase in the beam intensity required to maintain the power level. (authors)

Accelerating Science with the NERSC Burst Buffer Early User Program

Energy Technology Data Exchange (ETDEWEB)

Bhimji, Wahid [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bard, Debbie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Romanus, Melissa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutgers Univ., New Brunswick, NJ (United States); Paul, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ovsyannikov, Andrey [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Friesen, Brian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bryson, Matt [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Correa, Joaquin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lockwood, Glenn K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tsulaia, Vakho [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Byna, Suren [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Farrell, Steve [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gursoy, Doga [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Daley, Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Beckner, Vince [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Van Straalen, Brian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Trebotich, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tull, Craig [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Weber, Gunther H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wright, Nicholas J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Antypas, Katie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Prabhat, none [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-01-01

NVRAM-based Burst Buffers are an important part of the emerging HPC storage landscape. The National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory recently installed one of the first Burst Buffer systems as part of its new Cori supercomputer, collaborating with Cray on the development of the DataWarp software. NERSC has a diverse user base comprised of over 6500 users in 700 different projects spanning a wide variety of scientific computing applications. The use-cases of the Burst Buffer at NERSC are therefore also considerable and diverse. We describe here performance measurements and lessons learned from the Burst Buffer Early User Program at NERSC, which selected a number of research projects to gain early access to the Burst Buffer and exercise its capability to enable new scientific advancements. To the best of our knowledge this is the first time a Burst Buffer has been stressed at scale by diverse, real user workloads and therefore these lessons will be of considerable benefit to shaping the developing use of Burst Buffers at HPC centers.

A comparison of buffered lidocaine versus ELA-Max before peripheral intravenous catheter insertions in children.

Science.gov (United States)

Luhmann, Janet; Hurt, Sarah; Shootman, Mario; Kennedy, Robert

2004-03-01

Peripheral intravenous catheter (PIV) insertion is a common, painful experience for many children in the pediatric emergency department. Although local anesthetics such as injected buffered lidocaine have been shown to be effective at reducing pain and anxiety associated with PIV insertion, they are not routinely used. ELA-Max, a topical local anesthetic, has the advantage of needle-free administration but has not been compared with buffered lidocaine for PIV insertion. To compare the reduction of pain and anxiety during PIV insertion provided by subcutaneous buffered 1% lidocaine or topical ELA-Max in children. A randomized trial in children 4 to 17 years old undergoing PIV insertion with 22-gauge catheters was conducted. Children received either buffered lidocaine or ELA-Max. Buffered lidocaine was administered by using 30-gauge needles to inject 0.1 to 0.2 mL subcutaneously just before PIV insertion. ELA-Max was applied to the skin and occluded with Tegaderm 30 minutes before PIV insertion. Self-reported Visual Analog Scale (VAS) questionnaires (rating on a scale of 1-10; 1 = no pain, anxiety) were completed by patients and their parents before PIV insertion to assess baseline perceptions about pain and anxiety associated with PIV insertion and immediately after PIV insertion to assess pain and anxiety associated with the experience. After PIV insertion, the nurse who inserted the PIV also completed a VAS questionnaire assessing technical difficulty and satisfaction with the local anesthesia. A blinded observer also completed a VAS questionnaire to assess pain and anxiety associated with the PIV insertion. Data were analyzed by using chi2 and t tests. Sixty-nine subjects were enrolled, and questionnaires were competed by all (mean age: 12.1 +/- 4.5 years; 61% female). There were no differences for buffered lidocaine and ELA-Max groups in age, gender, race, prior IV experience, or baseline pain and anxiety. There were no significant differences between buffered

Experiments on thermal conductivity in buffer materials for geologic repository

International Nuclear Information System (INIS)

Kanno, T.; Yano, T.; Wakamatsu, H.; Matsushima, E.

1989-01-01

Engineered barriers for geologic disposal for HLW are planned to consist of canister, overpack and buffer elements. One of important physical characteristics of buffer materials is determining temperature profiles within the near field in a repository. Buffer materials require high thermal conductivity to disperse radiogenic heat away to the host rock. As the buffer materials, compacted blocks of the mixture of sodium bentonite and sand have been the most promising candidate in some countries, e.g. Sweden, Switzerland and Japan. The authors have been carrying out a series of thermal dispersion experiments to evaluate thermal conductivity of bentonite/quartz sand blocks. In this study, the following two factors considered to affect thermal properties of the near field were examined: effective thermal conductivities of buffer materials, and heat transfer characteristics of the gap between overpack and buffer materials

pH variations during diafiltration due to buffer nonidealities.

Science.gov (United States)

Baek, Youngbin; Yang, Deyu; Singh, Nripen; Arunkumar, Abhiram; Ghose, Sanchayita; Li, Zheng Jian; Zydney, Andrew L

2017-11-01

Diafiltration is used for final formulation of essentially all biotherapeutics. Several studies have demonstrated that buffer/excipient concentrations in the final diafiltered product can be different than that in the diafiltration buffer due to interactions between buffer species and the protein product. However, recent work in our lab has shown variations in solution pH that are largely independent of the protein concentration during the first few diavolumes. Our hypothesis is that these pH variations are due to nonidealities in the acid-base equilibrium coefficient. A model was developed for the diafiltration process accounting for the ionic strength dependence of the pK a . Experimental results obtained using phosphate and histidine buffers were in excellent agreement with model predictions. A decrease in ionic strength leads to an increase in the pK a for the phosphate buffer, causing a shift in the solution pH, even under conditions where the initial feed and the diafiltration buffer are at the same pH. This effect could be eliminated by matching the ionic strength of the feed and diafiltration buffer. The experimental data and model provide new insights into the factors controlling the pH profile during diafiltration processes. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1555-1560, 2017. © 2017 American Institute of Chemical Engineers.

Methyl Bromide Commodity Fumigation Buffer Zone Lookup Tables

Science.gov (United States)

Product labels for methyl bromide used in commodity and structural fumigation include requirements for buffer zones around treated areas. The information on this page will allow you to find the appropriate buffer zone for your planned application.

Replenishing data descriptors in a DMA injection FIFO buffer

Science.gov (United States)

Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Cernohous, Bob R [Rochester, MN; Heidelberger, Philip [Cortlandt Manor, NY; Kumar, Sameer [White Plains, NY; Parker, Jeffrey J [Rochester, MN

2011-10-11

Methods, apparatus, and products are disclosed for replenishing data descriptors in a Direct Memory Access (`DMA`) injection first-in-first-out (`FIFO`) buffer that include: determining, by a messaging module on an origin compute node, whether a number of data descriptors in a DMA injection FIFO buffer exceeds a predetermined threshold, each data descriptor specifying an application message for transmission to a target compute node; queuing, by the messaging module, a plurality of new data descriptors in a pending descriptor queue if the number of the data descriptors in the DMA injection FIFO buffer exceeds the predetermined threshold; establishing, by the messaging module, interrupt criteria that specify when to replenish the injection FIFO buffer with the plurality of new data descriptors in the pending descriptor queue; and injecting, by the messaging module, the plurality of new data descriptors into the injection FIFO buffer in dependence upon the interrupt criteria.

Protein buffering in model systems and in whole human saliva.

Directory of Open Access Journals (Sweden)

Andreas Lamanda

Full Text Available The aim of this study was to quantify the buffer attributes (value, power, range and optimum of two model systems for whole human resting saliva, the purified proteins from whole human resting saliva and single proteins. Two model systems, the first containing amyloglucosidase and lysozyme, and the second containing amyloglucosidase and alpha-amylase, were shown to provide, in combination with hydrogencarbonate and di-hydrogenphosphate, almost identical buffer attributes as whole human resting saliva. It was further demonstrated that changes in the protein concentration as small as 0.1% may change the buffer value of a buffer solution up to 15 times. Additionally, it was shown that there was a protein concentration change in the same range (0.16% between saliva samples collected at the time periods of 13:00 and others collected at 9:00 am and 17:00. The mode of the protein expression changed between these samples corresponded to the change in basic buffer power and the change of the buffer value at pH 6.7. Finally, SDS Page and Ruthenium II tris (bathophenantroline disulfonate staining unveiled a constant protein expression in all samples except for one 50 kDa protein band. As the change in the expression pattern of that 50 kDa protein band corresponded to the change in basic buffer power and the buffer value at pH 6.7, it was reasonable to conclude that this 50 kDa protein band may contain the protein(s belonging to the protein buffer system of human saliva.

META-ANALYSIS OF NITROGEN REMOVAL IN RIPARIAN BUFFERS

Science.gov (United States)

Riparian buffer zones, the vegetated region adjacent to streams and wetlands, are thought to be effective at intercepting and controlling nitrogen loads entering water bodies. Riparian buffer width may be positively related to nitrogen removal effectiveness by influencing nitrog...

Buffer fluid

Energy Technology Data Exchange (ETDEWEB)

Mirzadzhanzade, A Kh; Dedusanko, G Ya; Dinaburg, L S; Markov, Yu M; Rasizade, Ya N; Rozov, V N; Sherstnev, N M

1979-08-30

A drilling fluid is suggested for separating the drilling and plugging fluids which contains as the base increased solution of polyacrylamide and additive. In order to increase the viscoelastic properties of the liquid with simultaneous decrease in the periods of its fabrication, the solution contains as an additive dry bentonite clay. In cases of the use of a buffer fluid under conditions of negative temperatures, it is necessary to add to it table salt or ethylene glycol.

Creep in buffer clay

International Nuclear Information System (INIS)

Pusch, R.; Adey, R.

1999-12-01

The study involved characterization of the microstructural arrangement and molecular forcefields in the buffer clay for getting a basis for selecting suitable creep models. It is concluded that the number of particles and wide range of the particle bond spectrum require that stochastical mechanics and thermodynamics will be considered and they are basic to the creep model proposed for predicting creep settlement of the canisters. The influence of the stress level on creep strain of MX-80 clay is not well known but for the buffer creep is approximately proportional to stress. Theoretical considerations suggest a moderate impact for temperatures up to 90 deg C and this is supported by model experiments. It is believed that the assumption of strain being proportional to temperature is conservative. The general performance of the stochastic model can be illustrated in principle by use of visco-elastic rheological models implying a time-related increase in viscosity. The shear-induced creep settlement under constant volume conditions calculated by using the proposed creep model is on the order of 1 mm in ten thousand years and up to a couple of millimeters in one million years. It is much smaller than the consolidation settlement, which is believed to be on the order of 10 mm. The general conclusion is that creep settlement of the canisters is very small and of no significance to the integrity of the buffer itself or of the canisters

Highly efficient treatment of aerobic vaginitis with simple acidic buffered gels: The importance of pH and buffers on the microenvironment of vaginas.

Science.gov (United States)

Sun, Xiaodong; Qiu, Haiying; Jin, Yiguang

2017-06-15

Aerobic vaginitis (AV) leads to uterus deep infection or preterm birth. Antibacterial agents are not optimal therapeutics of AV. Here, we report a series of temperature-sensitive in situ forming acidic buffered gels for topical treatment of AV, involving lactate, acetate, and citrate gels at pH 3.5, 5.0, and 6.5. AV rat models were prepared following vaginal infection with Staphylococcus aureus and Escherichia coli. In vitro/in vivo studies of the buffered gels were performed compared with ofloxacin gels and blank gels. All the buffered gels showed the lower in vitro antibacterial activities than ofloxacin gels but the better in vivo anti-S. aureus effects and similar anti-E. coli effects. The buffered gels improved Lactobacillus growth in the vaginas. Both the healthy rat vaginal pH and the pH of rat vaginas treated with the buffered gels were about 6.5 though the AV rat models or ones treated with ofloxacin gels still remained at the high pH more than 7.0. After treatments with the buffered gels, the vaginal smears changed to a clean state nearly without aerobic bacteria, the vaginal tissues were refreshed, and the immunoreactions were downregulated. The acidic buffered gels bring rapid decrease of local vaginal pH, high antibacterial activities, improvement of probiotics, and alleviation of inflammation. They are simple, highly efficient, and safe anti-AV formulations. Copyright © 2017 Elsevier B.V. All rights reserved.

Labview virtual instruments for calcium buffer calculations.

Science.gov (United States)

Reitz, Frederick B; Pollack, Gerald H

2003-01-01

Labview VIs based upon the calculator programs of Fabiato and Fabiato (J. Physiol. Paris 75 (1979) 463) are presented. The VIs comprise the necessary computations for the accurate preparation of multiple-metal buffers, for the back-calculation of buffer composition given known free metal concentrations and stability constants used, for the determination of free concentrations from a given buffer composition, and for the determination of apparent stability constants from absolute constants. As implemented, the VIs can concurrently account for up to three divalent metals, two monovalent metals and four ligands thereof, and the modular design of the VIs facilitates further extension of their capacity. As Labview VIs are inherently graphical, these VIs may serve as useful templates for those wishing to adapt this software to other platforms.

Hydrothermal stability of bentonite-based buffer materials

International Nuclear Information System (INIS)

Johnston, R.M.; Miller, H.G.

1985-02-01

The reactions expected in bentonite-based buffer materials under conditions typical of a nuclear fuel waste disposal include mineral transformations (e.g. smectite to illite; smectite to zeolite) and a range of low-temperature cementation reactions. The probable extent and significance of these reactions are reviewed, and other reactions involving proposed filler sands are also examined briefly. The effects of mineral transformations on buffer performance will be insignificant if disposal vault temperatures do not exceed 100-120 degrees C and pH remains in the range 4 to 8. At pH > 9, zeolitization and silica dissolution may occur and buffer stability cannot be assured. The effects of cementation reactions may be significant, but are difficult to predict and require further investigation

Density management and riparian buffer study in Western Oregon: Phase 1 results, launch of phase 2 [brochure

Science.gov (United States)

Rhonda Mazza

2009-01-01

Can we expedite the development of late-successional forest conditions by applying thinning treatments to young forest stands? What effect will these thinning treatments have on headwater ecosystems? These broad questions lie at the foundation of the Density Management and Riparian Buffer Study (DMS) of western Oregon.

Intra- and Inter-personal Consequences of Protective Buffering among Cancer Patients and Caregivers

Science.gov (United States)

Langer, Shelby L.; Brown, Jonathon D.; Syrjala, Karen L.

2009-01-01

BACKGROUND Protective buffering refers to hiding cancer-related thoughts and concerns from one’s spouse or partner. This study sought to examine the intra- and inter-personal consequences of protective buffering and motivations for such (desire to shield partner from distress, desire to shield self from distress). METHODS Eighty hematopoietic stem cell transplant patients and their spousal caregivers/ partners completed measures designed to assess protective buffering and relationship satisfaction at two time points: prior to the transplant (T1) and 50 days post-transplant (T2). Overall mental health was also assessed at T2. RESULTS There was moderate agreement between one dyad member’s reported buffering of his/ her partner, and the partner’s perception of the extent to which s/he felt buffered. Caregivers buffered patients more than patients buffered caregivers, especially at T2. The more participants buffered their partners at T2, and the more they felt buffered, the lower their concurrent relationship satisfaction and the poorer their mental health. The latter effect was particularly true for patients who buffered, and patients who felt buffered. With respect to motivations, patients who buffered primarily to protect their partner at T1 reported increases in relationship satisfaction over time, but when they did so at T2, their caregiver reported concurrent decreases in relationship satisfaction. CONCLUSIONS Protective buffering is costly, in that those who buffer and those who feel buffered report adverse psychosocial outcomes. In addition, buffering enacted by patients with an intention to help may prove counterproductive, ultimately hurting the object of such protection. PMID:19731352

Optimizing the availability of a buffered industrial process

Science.gov (United States)

Martz, Jr., Harry F.; Hamada, Michael S.; Koehler, Arthur J.; Berg, Eric C.

2004-08-24

A computer-implemented process determines optimum configuration parameters for a buffered industrial process. A population size is initialized by randomly selecting a first set of design and operation values associated with subsystems and buffers of the buffered industrial process to form a set of operating parameters for each member of the population. An availability discrete event simulation (ADES) is performed on each member of the population to determine the product-based availability of each member. A new population is formed having members with a second set of design and operation values related to the first set of design and operation values through a genetic algorithm and the product-based availability determined by the ADES. Subsequent population members are then determined by iterating the genetic algorithm with product-based availability determined by ADES to form improved design and operation values from which the configuration parameters are selected for the buffered industrial process.

Buffer strip effect on terbuthylazine, desethyl-terbuthylazine and S-metolachlor runoff from maize fields in Northern Italy.

Science.gov (United States)

Milan, Marco; Vidotto, Francesco; Piano, Serenella; Negre, Michèle; Ferrero, Aldo

2013-01-01

The effectiveness of a 6 m wide vegetative buffer strip for reducing runoff of S-metolachlor, terbuthylazine and desethyl-terbuthylazine was studied in 2007-2008 in Northern Italy. Two cultivated fields, with and without the buffer strip, were compared. Residues of the chemicals were investigated in runoff water collected after runoff events and their dissipation in the soil was studied. The highest concentration of the chemicals in water occurred in samples collected from the unbuffered field at the first runoff events. Losses of terbuthylazine and S-metolachlor in runoff waters were particularly high in 2007 (2.6% and 0.9% of the amount applied, respectively). Soil half-life of terbuthylazine and S-metolachlor ranged between 12.1 and 8.9 days and 16 and 7 days, respectively. The presence of desethyl-terbuthylazine was related to parent compound degradation. The buffer strip allowed an important reduction of chemical content in water (> 90%), in particular during the first runoff events.

Concentrated flow paths in riparian buffer zones of southern Illinois

Science.gov (United States)

R.C. Pankau; J.E. Schoonover; K.W.J. Willard; P.J. Edwards

2012-01-01

Riparian buffers in agricultural landscapes should be designed to trap pollutants in overland flow by slowing, filtering, and infiltrating surface runoff entering the buffer via sheet flow. However, observational evidence suggests that concentrated flow is prevalent from agricultural fields. Over time sediment can accumulate in riparian buffers forming berms that...

TRIO: Burst Buffer Based I/O Orchestration

Energy Technology Data Exchange (ETDEWEB)

Wang, Teng [Auburn University; Oral, H Sarp [ORNL; Pritchard, Michael [Auburn University; Wang, Bin [Auburn University; Yu, Weikuan [Auburn University

2015-01-01

The growing computing power on leadership HPC systems is often accompanied by ever-escalating failure rates. Checkpointing is a common defensive mechanism used by scientific applications for failure recovery. However, directly writing the large and bursty checkpointing dataset to parallel filesystem can incur significant I/O contention on storage servers. Such contention in turn degrades the raw bandwidth utilization of storage servers and prolongs the average job I/O time of concurrent applications. Recently burst buffer has been proposed as an intermediate layer to absorb the bursty I/O traffic from compute nodes to storage backend. But an I/O orchestration mechanism is still desired to efficiently move checkpointing data from bursty buffers to storage backend. In this paper, we propose a burst buffer based I/O orchestration framework, named TRIO, to intercept and reshape the bursty writes for better sequential write traffic to storage severs. Meanwhile, TRIO coordinates the flushing orders among concurrent burst buffers to alleviate the contention on storage server bandwidth. Our experimental results reveal that TRIO can deliver 30.5% higher bandwidth and reduce the average job I/O time by 37% on average for data-intensive applications in various checkpointing scenarios.

Buffer-gas-induced absorption resonances in Rb vapor

International Nuclear Information System (INIS)

Mikhailov, Eugeniy E.; Novikova, Irina; Rostovtsev, Yuri V.; Welch, George R.

2004-01-01

We observe transformation of the electromagnetically induced transparency (EIT) resonance into an absorption resonance in a Λ interaction configuration in a cell filled with 87 Rb and a buffer gas. This transformation occurs as one-photon detuning of the coupling fields is varied from the atomic transition. No such absorption resonance is found in the absence of a buffer gas. The width of the absorption resonance is several times smaller than the width of the EIT resonance, and the changes of absorption near these resonances are about the same. Similar absorption resonances are detected in the Hanle configuration in a buffered cell

Buffer Zone Sign Template

Science.gov (United States)

The certified pesticide applicator is required to post a comparable sign, designating a buffer zone around the soil fumigant application block in order to control exposure risk. It must include the don't walk symbol, product name, and applicator contact.

Thermo-hydro-mechanical modelling of buffer, synthesis report

International Nuclear Information System (INIS)

Toprak, E.; Mokni, N.; Olivella, S.; Pintado, X.

2013-08-01

This study addresses analyses of coupled thermo-hydro-mechanical (THM) processes in a scheme considered for the spent nuclear fuel repository in Olkiluoto (Finland). The finite element code CODE B RIGHT is used to perform modelling calculations. The objective of the THM modelling was to study some fundamental design parameters. The time required to reach full saturation, the maximum temperature reached in the canister, the deformations in the buffer-backfill interface, the stress-deformation balance between the buffer and the backfill, the swelling pressure developed and the homogenization process development are critical variables. Because of the complexity of the THM processes developed, only a single deposition hole has been modelled with realistic boundary conditions which take into account the entire repository. A thermal calculation has been performed to adopt appropriate boundary conditions for a reduced domain. The modelling has been done under axisymmetric conditions. As a material model for the buffer bentonite and backfill soil, the Barcelona Basic Model (BBM) has been used. Simulation of laboratory tests conducted at B and Tech under supervision of Posiva has been carried out in order to determine the fundamental mechanical parameters for modelling the behaviour of MX-80 bentonite using the BBM model. The modelling process of the buffer-backfill interface is an essential part of tunnel backfill design. The calculations will aim to determine deformations in this intersection, the behaviour of which is important for the buffer swelling. The homogenization process is a key issue as well. Porosity evolution during the saturation process is evaluated in order to check if the final saturated density accomplishes the homogenization requirements. This report also describes the effect of the existence of an air-filled gap located between the canister and the bentonite block rings in thermo-hydro-mechanical behaviour of the future spent nuclear fuel repository in

Thermo-hydro-mechanical modelling of buffer, synthesis report

Energy Technology Data Exchange (ETDEWEB)

Toprak, E.; Mokni, N.; Olivella, S. [Universitat Politecnica de Catalunya, Barcelona (Spain); Pintado, X. [B and Tech Oy, Helsinki (Finland)

2013-08-15

This study addresses analyses of coupled thermo-hydro-mechanical (THM) processes in a scheme considered for the spent nuclear fuel repository in Olkiluoto (Finland). The finite element code CODE{sub B}RIGHT is used to perform modelling calculations. The objective of the THM modelling was to study some fundamental design parameters. The time required to reach full saturation, the maximum temperature reached in the canister, the deformations in the buffer-backfill interface, the stress-deformation balance between the buffer and the backfill, the swelling pressure developed and the homogenization process development are critical variables. Because of the complexity of the THM processes developed, only a single deposition hole has been modelled with realistic boundary conditions which take into account the entire repository. A thermal calculation has been performed to adopt appropriate boundary conditions for a reduced domain. The modelling has been done under axisymmetric conditions. As a material model for the buffer bentonite and backfill soil, the Barcelona Basic Model (BBM) has been used. Simulation of laboratory tests conducted at B and Tech under supervision of Posiva has been carried out in order to determine the fundamental mechanical parameters for modelling the behaviour of MX-80 bentonite using the BBM model. The modelling process of the buffer-backfill interface is an essential part of tunnel backfill design. The calculations will aim to determine deformations in this intersection, the behaviour of which is important for the buffer swelling. The homogenization process is a key issue as well. Porosity evolution during the saturation process is evaluated in order to check if the final saturated density accomplishes the homogenization requirements. This report also describes the effect of the existence of an air-filled gap located between the canister and the bentonite block rings in thermo-hydro-mechanical behaviour of the future spent nuclear fuel

Stream water responses to timber harvest: Riparian buffer width effectiveness

Science.gov (United States)

Barton D. Clinton

2011-01-01

Vegetated riparian buffers are critical for protecting aquatic and terrestrial processes and habitats in southern Appalachian ecosystems. In this case study, we examined the effect of riparian buffer width on stream water quality following upland forest management activities in four headwater catchments. Three riparian buffer widths were delineated prior to cutting; 0m...

Association between airborne PM2.5 chemical constituents and birth weight—implication of buffer exposure assignment

International Nuclear Information System (INIS)

Ebisu, Keita; Bell, Michelle L; Belanger, Kathleen

2014-01-01

Several papers reported associations between airborne fine particulate matter (PM 2.5 ) and birth weight, though findings are inconsistent across studies. Conflicting results might be due to (1) different PM 2.5 chemical structure across locations, and (2) various exposure assignment methods across studies even among the studies that use ambient monitors to assess exposure. We investigated associations between birth weight and PM 2.5 chemical constituents, considering issues arising from choice of buffer size (i.e. distance between residence and pollution monitor). We estimated the association between each pollutant and term birth weight applying buffers of 5 to 30 km in Connecticut (2000–2006), in the New England region of the USA. We also investigated the implication of the choice of buffer size in relation to population characteristics, such as socioeconomic status. Results indicate that some PM 2.5 chemical constituents, such as nitrate, are associated with lower birth weight and appear more harmful than other constituents. However, associations vary with buffer size and the implications of different buffer sizes may differ by pollutant. A homogeneous pollutant level within a certain distance is a common assumption in many environmental epidemiology studies, but the validity of this assumption may vary by pollutant. Furthermore, we found that areas close to monitors reflect more minority and lower socio-economic populations, which implies that different exposure approaches may result in different types of study populations. Our findings demonstrate that choosing an exposure method involves key tradeoffs of the impacts of exposure misclassification, sample size, and population characteristics. (letter)

Association between airborne PM2.5 chemical constituents and birth weight—implication of buffer exposure assignment

Science.gov (United States)

Ebisu, Keita; Belanger, Kathleen; Bell, Michelle L.

2014-08-01

Several papers reported associations between airborne fine particulate matter (PM2.5) and birth weight, though findings are inconsistent across studies. Conflicting results might be due to (1) different PM2.5 chemical structure across locations, and (2) various exposure assignment methods across studies even among the studies that use ambient monitors to assess exposure. We investigated associations between birth weight and PM2.5 chemical constituents, considering issues arising from choice of buffer size (i.e. distance between residence and pollution monitor). We estimated the association between each pollutant and term birth weight applying buffers of 5 to 30 km in Connecticut (2000-2006), in the New England region of the USA. We also investigated the implication of the choice of buffer size in relation to population characteristics, such as socioeconomic status. Results indicate that some PM2.5 chemical constituents, such as nitrate, are associated with lower birth weight and appear more harmful than other constituents. However, associations vary with buffer size and the implications of different buffer sizes may differ by pollutant. A homogeneous pollutant level within a certain distance is a common assumption in many environmental epidemiology studies, but the validity of this assumption may vary by pollutant. Furthermore, we found that areas close to monitors reflect more minority and lower socio-economic populations, which implies that different exposure approaches may result in different types of study populations. Our findings demonstrate that choosing an exposure method involves key tradeoffs of the impacts of exposure misclassification, sample size, and population characteristics.

Substrate-induced magnetism in epitaxial graphene buffer layers.

Science.gov (United States)

Ramasubramaniam, A; Medhekar, N V; Shenoy, V B

2009-07-08

Magnetism in graphene is of fundamental as well as technological interest, with potential applications in molecular magnets and spintronic devices. While defects and/or adsorbates in freestanding graphene nanoribbons and graphene sheets have been shown to cause itinerant magnetism, controlling the density and distribution of defects and adsorbates is in general difficult. We show from first principles calculations that graphene buffer layers on SiC(0001) can also show intrinsic magnetism. The formation of graphene-substrate chemical bonds disrupts the graphene pi-bonds and causes localization of graphene states near the Fermi level. Exchange interactions between these states lead to itinerant magnetism in the graphene buffer layer. We demonstrate the occurrence of magnetism in graphene buffer layers on both bulk-terminated as well as more realistic adatom-terminated SiC(0001) surfaces. Our calculations show that adatom density has a profound effect on the spin distribution in the graphene buffer layer, thereby providing a means of engineering magnetism in epitaxial graphene.

Role of histidine-related compounds to intracellular buffering in fish skeletal muscle.

Science.gov (United States)

Abe, H; Dobson, G P; Hoeger, U; Parkhouse, W S

1985-10-01

Histidine-related compounds (HRC) were analyzed in fish skeletal muscle as a means of identifying their precise role in intracellular buffering. Fish muscle was used because it contains two functionally and spatially distinct fiber types, red and white. Two fish species, rainbow trout (Salmo gairdneri) and the Pacific blue marlin (Makaira nigricans), were studied because these species demonstrate widely different activity patterns. Marlin red and white muscle buffer capacity was two times higher than trout with white muscle, buffering being two times greater than red in both species. Buffer capacity was highest in the 6.5-7.5 pH range for all tissues, which corresponded to their high anserine levels. The titrated HRC buffering was greater than the observed HRC buffering, which suggested that not all HRC were available to absorb protons. The HRC contribution to total cellular buffering varied from a high of 62% for marlin white to a low of 7% for trout red. The other principal buffers were found to be phosphate and protein with taurine contributing within red muscle in the 7.0-8.0 pH range. HRC were found to be dominant in skeletal muscle buffering by principally accounting for the buffering capacity differences found between the species and fiber types.

The effect of respiration buffer composition on mitochondrial metabolism and function

OpenAIRE

Wollenman, Lucas C.; Vander Ploeg, Matthew R.; Miller, Mackinzie L.; Zhang, Yizhu; Bazil, Jason N.

2017-01-01

Functional studies on isolated mitochondria critically rely on the right choice of respiration buffer. Differences in buffer composition can lead to dramatically different respiration rates leading to difficulties in comparing prior studies. The ideal buffer facilities high ADP-stimulated respiratory rates and minimizes substrate transport effects so that the ability to distinguish between various treatments and conditions is maximal. In this study, we analyzed a variety of respiration buffer...

Swelling characteristics of buffer material

International Nuclear Information System (INIS)

Suzuki, Hideaki; Fujita, Tomoo

1999-12-01

After emplacement of the engineered barrier system (EBS), it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanism, infiltration of groundwater from the surrounding rock into the EBS, generation of swelling pressure in the buffer due to water infiltration and the stress imposed by the overburden pressure. These phenomena are not all independent, but can be strongly influenced by, and coupled with, each other. Evaluating these coupled thermo-hydro-mechanical phenomena is important in order to clarify the initial transient behavior of the engineered barrier system within the near-field. This report describes the results on measurement of swelling amount and stress at boundary built up under restraint condition with water uptake. The following results are identified. (1) The swelling stress of buffer material at saturated condition tends to be independent of effects of pore water pressure and synthetic sea water, and to decrease with increasing temperature. The swelling stress can be explained by the effective dry density. (2) The strain due to swelling estimated from the results of the swelling amount of buffer material is proportional to swelling stress. (3) The swelling stress and strain under unsaturated condition increase with water uptake. (author)

A readout buffer prototype for ATLAS high-level triggers

CERN Document Server

Calvet, D; Huet, M; Le Dû, P; Mandjavidze, I D; Mur, M

2001-01-01

Readout buffers are critical components in the dataflow chain of the ATLAS trigger/data-acquisition system. At up to 75 kHz, after each Level-1 trigger accept signal, these devices receive and store digitized data from groups of front-end electronic channels. Several readout buffers are grouped to form a readout buffer complex that acts as a data server for the high-level trigger selection algorithms and for the final data-collection system. This paper describes a functional prototype of a readout buffer based on a custom-made PCI mezzanine card that is designed to accept input data at up to 160 MB /s, to store up to 8 MB of data, and to distribute data chunks at the desired request rate. We describe the hardware of the card that is based on an Intel 1960 processor and complex programmable logic devices. We present the integration of several of these cards in a readout buffer complex. We measure various performance figures and discuss to which extent these can fulfil ATLAS needs. (5 refs).

Lucas Heights buffer zone: plan of management

International Nuclear Information System (INIS)

1986-01-01

This plan is being used by the Commission as a guide for its management of the Lucas Heights buffer zone, which is essentially a circular area having a 1-6 km radius around the HIFAR reactor. Aspects covered by this plan include past uses, current use, objectives for buffer zone land management, emergency evacuation, resource conservation, archaeology, fire, access, rehabilitation of disturbed areas, resource management and plan implementation

Buffer erosion: An overview of concepts and potential safety consequences

International Nuclear Information System (INIS)

Apted, Michael J.; Arthur, Randy; Bennett, David; Savage, David; Saellfors, Goeran; Wennerstroem, Haakan

2010-11-01

In its safety analysis SR-Can, SKB reported preliminary results and conclusions on the mechanisms of bentonite colloid formation and stability, with a rough estimate of the consequences of loss of bentonite buffer by erosion. With the review of SR-Can the authorities (SKI and SSI) commented that erosion of the buffer had the greatest safety significance, that the understanding of the mechanisms of buffer erosion was inadequate, and that more work would be required to arrive at robust estimates of the extent and impacts of buffer erosion. After the SR-Can report, SKB started a two-year research project on buffer erosion. The results from this two-year project have been reported in several SKB technical reports. SSM started this project to build up its own competence in the related scientific areas by a preliminary evaluation of SKB's research results

Buffer erosion: An overview of concepts and potential safety consequences

Energy Technology Data Exchange (ETDEWEB)

Apted, Michael J.; Arthur, Randy (INTERA Incorporated, Denver, CO (United States)); Bennett, David (TerraSalus Limited, Rutland (United Kingdom)); Savage, David (Savage Earth Associates Limited, Bournemouth (United Kingdom)); Saellfors, Goeran (GeoForce AB, Billdal (Sweden)); Wennerstroem, Haakan (Dept. of Chemistry, Lund Univ., Lund (Sweden))

2010-11-15

In its safety analysis SR-Can, SKB reported preliminary results and conclusions on the mechanisms of bentonite colloid formation and stability, with a rough estimate of the consequences of loss of bentonite buffer by erosion. With the review of SR-Can the authorities (SKI and SSI) commented that erosion of the buffer had the greatest safety significance, that the understanding of the mechanisms of buffer erosion was inadequate, and that more work would be required to arrive at robust estimates of the extent and impacts of buffer erosion. After the SR-Can report, SKB started a two-year research project on buffer erosion. The results from this two-year project have been reported in several SKB technical reports. SSM started this project to build up its own competence in the related scientific areas by a preliminary evaluation of SKB's research results

Buffer capacity of the coelomic fluid in echinoderms.

Science.gov (United States)

Collard, Marie; Laitat, Kim; Moulin, Laure; Catarino, Ana I; Grosjean, Philippe; Dubois, Philippe

2013-09-01

The increase in atmospheric CO2 due to anthropogenic activity results in an acidification of the surface waters of the oceans. The impact of these chemical changes depends on the considered organisms. In particular, it depends on the ability of the organism to control the pH of its inner fluids. Among echinoderms, this ability seems to differ significantly according to species or taxa. In the present paper, we investigated the buffer capacity of the coelomic fluid in different echinoderm taxa as well as factors modifying this capacity. Euechinoidea (sea urchins except Cidaroidea) present a very high buffer capacity of the coelomic fluid (from 0.8 to 1.8mmolkg(-1) SW above that of seawater), while Cidaroidea (other sea urchins), starfish and holothurians have a significantly lower one (from -0.1 to 0.4mmolkg(-1) SW compared to seawater). We hypothesize that this is linked to the more efficient gas exchange structures present in the three last taxa, whereas Euechinoidea evolved specific buffer systems to compensate lower gas exchange abilities. The constituents of the buffer capacity and the factors influencing it were investigated in the sea urchin Paracentrotus lividus and the starfish Asterias rubens. Buffer capacity is primarily due to the bicarbonate buffer system of seawater (representing about 63% for sea urchins and 92% for starfish). It is also partly due to coelomocytes present in the coelomic fluid (around 8% for both) and, in P. lividus only, a compound of an apparent size larger than 3kDa is involved (about 15%). Feeding increased the buffer capacity in P. lividus (to a difference with seawater of about 2.3mmolkg(-1) SW compared to unfed ones who showed a difference of about 0.5mmolkg(-1) SW) but not in A. rubens (difference with seawater of about 0.2 for both conditions). In P. lividus, decreased seawater pH induced an increase of the buffer capacity of individuals maintained at pH7.7 to about twice that of the control individuals and, for those at pH7

A dynamic programming algorithm for the buffer allocation problem in homogeneous asymptotically reliable serial production lines

Directory of Open Access Journals (Sweden)

Diamantidis A. C.

2004-01-01

Full Text Available In this study, the buffer allocation problem (BAP in homogeneous, asymptotically reliable serial production lines is considered. A known aggregation method, given by Lim, Meerkov, and Top (1990, for the performance evaluation (i.e., estimation of throughput of this type of production lines when the buffer allocation is known, is used as an evaluative method in conjunction with a newly developed dynamic programming (DP algorithm for the BAP. The proposed algorithm is applied to production lines where the number of machines is varying from four up to a hundred machines. The proposed algorithm is fast because it reduces the volume of computations by rejecting allocations that do not lead to maximization of the line's throughput. Numerical results are also given for large production lines.

Imidacloprid sorption and transport in cropland, grass buffer and riparian buffer soils

Science.gov (United States)

Satkowski, Laura E.; Goyne, Keith W.; Anderson, Stephen H.; Lerch, Robert N.; Allen, Craig R.; Snow, Daniel D.

2018-01-01

An understanding of neonicotinoid sorption and transport in soil is critical for determining and mitigating environmental risk associated with the most widely used class of insecticides. The objective of this study was to evaluate mobility and transport of the neonicotinoid imidacloprid (ICD) in soils collected from cropland, grass vegetative buffer strip (VBS), and riparian VBS soils. Soils were collected at six randomly chosen sites within grids that encompassed all three land uses. Single-point equilibrium batch sorption experiments were conducted using radio-labeled (14C) ICD to determine solid–solution partition coefficients (Kd). Column experiments were conducted using soils collected from the three vegetation treatments at one site by packing soil into glass columns. Water flow was characterized by applying Br− as a nonreactive tracer. A single pulse of 14C-ICD was then applied, and ICD leaching was monitored for up to 45 d. Bromide and ICD breakthrough curves for each column were simulated using CXTFIT and HYDRUS-1D models. Sorption results indicated that ICD sorbs more strongly to riparian VBS (Kd = 22.6 L kg−1) than crop (Kd = 11.3 L kg−1) soils. Soil organic C was the strongest predictor of ICD sorption (p < 0.0001). The column transport study found mean peak concentrations of ICD at 5.83, 10.84, and 23.8 pore volumes for crop, grass VBS, and riparian VBS soils, respectively. HYDRUS-1D results indicated that the two-site, one-rate linear reversible model best described results of the breakthrough curves, indicating the complexity of ICD sorption and demonstrating its mobility in soil. Greater sorption and longer retention by the grass and riparian VBS soils than the cropland soil suggests that VBS may be a viable means to mitigate ICD loss from agroecosystems, thereby preventing ICD transport into surface water, groundwater, or drinking water resources.

Moisture buffer capacity of different insulation materials

DEFF Research Database (Denmark)

Peuhkuri, Ruut Hannele; Rode, Carsten; Hansen, Kurt Kielsgaard

2004-01-01

. In the isothermal tests the material samples were exposed to the same change in the relative humidity of the ambient air on both sides, while the samples were exposed to variations in relative humidity only on the cold side in the non-isothermal tests. The results of these rather different measurement principles...... lead to more durable constructions. In this paper, a large range of very different thermal insulation materials have been tested in specially constructed laboratory facilities to determine their moisture buffer capacity. Both isothermal and nonisothermal experimental set-ups have been used...... are discussed, and different ways are presented how to determine the moisture buffer capacity of the materials using partly standard material parameters and partly parameters determined from the actual measurements. The results so far show that the determination of moisture buffer capacity is very sensitive...

Buffers and vegetative filter strips

Science.gov (United States)

Matthew J. Helmers; Thomas M. Isenhart; Michael G. Dosskey; Seth M. Dabney

2008-01-01

This chapter describes the use of buffers and vegetative filter strips relative to water quality. In particular, we primarily discuss the herbaceous components of the following NRCS Conservation Practice Standards.

Surface modification by preparation of buffer zone in glow-discharge plasma

International Nuclear Information System (INIS)

Cho, D.L.

1986-01-01

Reactive species, energetic particles, and uv radiation in the plasma created by a glow discharge strongly interact with solid surfaces under the influence of the plasma. As a result of the strong interaction, various physical and chemical reactions, unique and advantageous for the surface modification of solid materials, occur on the solid surfaces. The surface modification is carried out through formation of a thin buffering layer on the solid surface. The preparation of a buffer zone on solid surfaces for surface modification is described. Two kinds of a buffer zone are prepared by plasma polymerization, or simultaneous sputter deposition of electrode material with plasma polymerization: a transitional buffer zone and a graded buffer zone. Important factors for preparation of the buffer zone (pre-conditioning of a substrate surface, thin-film deposition, post-treatment of the film, magnetron discharge, energy input, geometry of a substrate and a plasma) are discussed

A Buffer Stock Model to Ensure Price Stabilization and Availability of Seasonal Staple Food under Free Trade Considerations

Directory of Open Access Journals (Sweden)

Wahyudi Sutopo

2012-07-01

Full Text Available The price volatility and scarcity have been became a great problem in the distribution system of seasonal staple food produced by agro industry. It has salient supply disparity during the harvest and planting season. This condition could cause disadvantages to the stakeholders such as producer, wholesaler, consumer, and government. This paper proposes a buffer stock model under free trade considerations to substitute quantitative restrictions and tariffs by indirect market intervention instrument. The instrument was developed through buffer stock scheme in accordance with warehouse receipt system (WRS and collateral management system. The public service institution for staple food buffer stock (BLUPP is proposed as wholesaler’s competitor with main responsibility to ensure price stabilization and availability of staple food. Multi criteria decision making is formulated as single objective a mixed integer non linear programming (MINLP. The result shows that the proposed model can be applied to solve the distribution problem and can give more promising outcome than its counterpart, the direct market intervention instrument.

Buffer modulation of menadione-induced oxidative stress in Saccharomyces cerevisiae.

Science.gov (United States)

Lushchak, Oleh V; Bayliak, Maria M; Korobova, Olha V; Levine, Rodney L; Lushchak, Volodymyr I

2009-01-01

The objective of this study was to compare, in vivo, the effects of bicarbonate and phosphate buffers on survival and menadione-induced oxidative stress in yeast cells. The latter were treated with different concentrations of menadione in the presence of these two buffers. At 25 mM concentration of buffers, menadione only slightly reduced yeast surviving; at 50 mM concentration, cell killing by menadione was much more pronounced in bicarbonate than in phosphate buffer. Although the content of protein carbonyl groups did not show development of oxidative stress under menadione-induced stress, inactivation of aconitase and decrease in glutathione level mirrored its induction. However, cellular glutathione and aconitase activity decrease did not correlate with yeast survival. In vitro, aconitase was more quickly inactivated in 50 mM carbonate, than in 50 mM phosphate buffer. The possible involvement of the carbonate radical in these processes is discussed.

Thin film photovoltaic devices with a minimally conductive buffer layer

Science.gov (United States)

Barnes, Teresa M.; Burst, James

2016-11-15

A thin film photovoltaic device (100) with a tunable, minimally conductive buffer (128) layer is provided. The photovoltaic device (100) may include a back contact (150), a transparent front contact stack (120), and an absorber (140) positioned between the front contact stack (120) and the back contact (150). The front contact stack (120) may include a low resistivity transparent conductive oxide (TCO) layer (124) and a buffer layer (128) that is proximate to the absorber layer (140). The photovoltaic device (100) may also include a window layer (130) between the buffer layer (128) and the absorber (140). In some cases, the buffer layer (128) is minimally conductive, with its resistivity being tunable, and the buffer layer (128) may be formed as an alloy from a host oxide and a high-permittivity oxide. The high-permittivity oxide may further be chosen to have a bandgap greater than the host oxide.

Temperature buffer test. Dismantling operation

Energy Technology Data Exchange (ETDEWEB)

Aakesson, Mattias [Clay Technology AB, Lund (Sweden)

2010-12-15

The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite in the usual way, whereas the upper heater was surrounded by a ring of sand. The test was dismantled and sampled during a period from the end of October 2009 to the end of April 2010, and this report describes this operation. Different types of samples have been obtained during this operation. A large number of diameter 50 mm bentonite cores have been taken for analysis of water content and density. Large pieces, so-called big sectors, have been taken for hydro-mechanical and chemical characterizations. Finally, there has been an interest to obtain different types of interface samples in which bentonite were in contact with sand, iron or concrete. One goal has been to investigate the retrievability of the upper heater, given the possibility to remove the surrounding sand shield, and a retrieval test has therefore been performed. The sand in the shield was first removed with an industrial vacuum cleaner after loosening the material through mechanical means (with hammer drill and core machine). A front loader was subsequently used for applying a sufficient lifting force to release the heater from the bentonite underneath. The experiment has been documented in different aspects: measurements of the coordinate (height or radius) of different interfaces (between bentonite blocks and between bentonite and sand); verification of sensor positions and retrieval of sensors for subsequent

Temperature buffer test. Dismantling operation

International Nuclear Information System (INIS)

Aakesson, Mattias

2010-12-01

The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite in the usual way, whereas the upper heater was surrounded by a ring of sand. The test was dismantled and sampled during a period from the end of October 2009 to the end of April 2010, and this report describes this operation. Different types of samples have been obtained during this operation. A large number of diameter 50 mm bentonite cores have been taken for analysis of water content and density. Large pieces, so-called big sectors, have been taken for hydro-mechanical and chemical characterizations. Finally, there has been an interest to obtain different types of interface samples in which bentonite were in contact with sand, iron or concrete. One goal has been to investigate the retrievability of the upper heater, given the possibility to remove the surrounding sand shield, and a retrieval test has therefore been performed. The sand in the shield was first removed with an industrial vacuum cleaner after loosening the material through mechanical means (with hammer drill and core machine). A front loader was subsequently used for applying a sufficient lifting force to release the heater from the bentonite underneath. The experiment has been documented in different aspects: measurements of the coordinate (height or radius) of different interfaces (between bentonite blocks and between bentonite and sand); verification of sensor positions and retrieval of sensors for subsequent

Does social network site use buffer against well-being loss when older adults face reduced functional ability?

NARCIS (Netherlands)

van Ingen, Erik; Rains, Stephen A; Wright, Kevin B

2017-01-01

We examine the role of the Internet in dealing with problems in later life by analyzing whether direct and buffering models of social support can be applied to social network site (SNS) use. Whereas the direct model implies a positive effect of time spent using SNSs on subjective well-being, and a

Buffer provisioning for large-scale data-acquisition systems

CERN Document Server

AUTHOR|(SzGeCERN)756497; The ATLAS collaboration; Garcia Garcia, Pedro Javier; Froening, Holger; Vandelli, Wainer

2018-01-01

The data acquisition system of the ATLAS experiment, a major experiment of the Large Hadron Collider (LHC) at CERN, will go through a major upgrade in the next decade. The upgrade is driven by experimental physics requirements, calling for increased data rates on the order of 6~TB/s. By contrast, the data rate of the existing system is 160~GB/s. Among the changes in the upgraded system will be a very large buffer with a projected size on the order of 70 PB. The buffer role will be decoupling of data production from on-line data processing, storing data for periods of up to 24~hours until it can be analyzed by the event processing system. The larger buffer will allow a new data recording strategy, providing additional margins to handle variable data rates. At the same time it will provide sensible trade-offs between buffering space and on-line processing capabilities. This compromise between two resources will be possible since the data production cycle includes time periods where the experiment will not produ...

Flood risk reduction and flow buffering as ecosystem services - Part 2

NARCIS (Netherlands)

Noordwijk, Van Meine; Tanika, Lisa; Lusiana, Betha

2017-01-01

Watersheds buffer the temporal pattern of river flow relative to the temporal pattern of rainfall. This "ecosystem service" is inherent to geology and climate, but buffering also responds to human use and misuse of the landscape. Buffering can be part of management feedback loops if salient,

Effect of Coating Parameters of the Buffer Layer on the Shape Ratio of TRISO-Coated Particles

International Nuclear Information System (INIS)

KIm, Weon Ju; Park, Jong Hoon; Park, Ji Yeon; Lee, Young Woo; Chang, Jong Hwa

2005-01-01

Fuel for high temperature gas-cooled reactors (HTGR's) consists of TRISO-coated particles. Fluidized bed chemical vapor deposition (FBCVD) has been applied to fabricate the TRISO-coated fuel particles. The TRISO particles consist of UO 2 microspheres coated with layers of porous pyrolytic carbon (PyC), inner dense PyC (IPyC), SiC, and outer dense PyC (OPyC). The porous PyC coating layer, called the buffer layer, attenuates fission recoils and provides void volume for gaseous fission products and carbon monoxide. The buffer layer, which has the highest coating rate among the coating layers, shows the largest variation of the coating thickness within a particle and a batch. This could be the most plausible source of an asphericity in the TRISO particles. The aspherical particles are expected to have an inferior fuel performance. Miller et al. have predicted that a larger stress is developed within the coating layers and thus the failure probability increases in the particles with high aspect ratios. Therefore, the shape of the TRISO-coated particles should be controlled properly and has been one of the important inspection items for the quality control of the fabrication process. In this paper, we investigated the effect of coating parameters of the buffer layer on the shape of the TRISO particles. The flow rate of coating gas and the coating temperature were varied to control the buffer layer. The asphericity of the TRISO-coated particles was evaluated for the various coating conditions of the buffer layer, but at constant coating parameters for the IPyC/SiC/OPyC layers

Reduced endogenous Ca2+ buffering speeds active zone Ca2+ signaling.

Science.gov (United States)

Delvendahl, Igor; Jablonski, Lukasz; Baade, Carolin; Matveev, Victor; Neher, Erwin; Hallermann, Stefan

2015-06-09

Fast synchronous neurotransmitter release at the presynaptic active zone is triggered by local Ca(2+) signals, which are confined in their spatiotemporal extent by endogenous Ca(2+) buffers. However, it remains elusive how rapid and reliable Ca(2+) signaling can be sustained during repetitive release. Here, we established quantitative two-photon Ca(2+) imaging in cerebellar mossy fiber boutons, which fire at exceptionally high rates. We show that endogenous fixed buffers have a surprisingly low Ca(2+)-binding ratio (∼ 15) and low affinity, whereas mobile buffers have high affinity. Experimentally constrained modeling revealed that the low endogenous buffering promotes fast clearance of Ca(2+) from the active zone during repetitive firing. Measuring Ca(2+) signals at different distances from active zones with ultra-high-resolution confirmed our model predictions. Our results lead to the concept that reduced Ca(2+) buffering enables fast active zone Ca(2+) signaling, suggesting that the strength of endogenous Ca(2+) buffering limits the rate of synchronous synaptic transmission.

Lean buffering in serial production lines with Bernoulli machines

Directory of Open Access Journals (Sweden)

A. B. Hu

2006-01-01

Full Text Available Lean buffering is the smallest buffer capacity necessary to ensure the desired production rate of a manufacturing system. In this paper, analytical methods for selecting lean buffering in serial production lines are developed under the assumption that the machines obey the Bernoulli reliability model. Both closed-form expressions and recursive approaches are investigated. The cases of identical and nonidentical machines are analyzed. Results obtained can be useful for production line designers and production managers to maintain the required production rate with the smallest possible inventories.

Chemical buffering in natural and engineered barrier systems: Thermodynamic constraints and performance assessment consequences

International Nuclear Information System (INIS)

Arthur, R.C.; Wei Zhou

2000-12-01

Thermodynamic and kinetic constraints on the chemical buffering properties of natural and engineered-barrier systems are derived in this study from theoretical descriptions, incorporated in the reaction-path model, of reversible and irreversible mass transfer in multicomponent, multiphase systems. The buffering properties of such systems are conditional properties because they refer to a specific aqueous species in a system that is open with respect to a specific reactant. The solution to a mathematical statement of this concept requires evaluation of the dependence of the activity of the buffered species on incremental changes in the overall reaction-progress variable. This dependence can be represented by a truncated Taylor's series expansion, where the values of associated derivatives are calculated using finite-difference techniques and mass-balance, charge-balance and mass-action constraints. Kinetic constraints on buffering behavior can also be described if the relation between reactant flux and reaction rate is well defined. This relation is explicit for the important case of advective groundwater flow and water-rock interaction. We apply the theoretical basis of the chemical buffering concept to processes that could affect the performance of a deep geologic repository for nuclear waste. Specifically, we focus on the likelihood that an inverse relation must exist between the buffer intensity and the migration velocity of reaction fronts in systems involving advective or diffusive mass transport. A quantitative understanding of this relation would provide the basis for evaluating the potential role of chemical buffering in achieving the isolation and retardation functions, of the EBS and geosphere in a KBS-3 repository. Our preliminary evaluation of this role considers the effects of chemical buffering on the propagation velocity of a pH front in both the near- and far field. We use a geochemical modeling technique compatible with the reaction-path model to

Semi-mechanistic partial buffer approach to modeling pH, the buffer properties, and the distribution of ionic species in complex solutions.

Science.gov (United States)

Dougherty, Daniel P; Da Conceicao Neta, Edith Ramos; McFeeters, Roger F; Lubkin, Sharon R; Breidt, Frederick

2006-08-09

In many biological science and food processing applications, it is very important to control or modify pH. However, the complex, unknown composition of biological media and foods often limits the utility of purely theoretical approaches to modeling pH and calculating the distributions of ionizable species. This paper provides general formulas and efficient algorithms for predicting the pH, titration, ionic species concentrations, buffer capacity, and ionic strength of buffer solutions containing both defined and undefined components. A flexible, semi-mechanistic, partial buffering (SMPB) approach is presented that uses local polynomial regression to model the buffering influence of complex or undefined components in a solution, while identified components of known concentration are modeled using expressions based on extensions of the standard acid-base theory. The SMPB method is implemented in a freeware package, (pH)Tools, for use with Matlab. We validated the predictive accuracy of these methods by using strong acid titrations of cucumber slurries to predict the amount of a weak acid required to adjust pH to selected target values.

Implementing the countercyclical capital buffer in South Africa: Practical considerations

Directory of Open Access Journals (Sweden)

Pravin Burra

2015-03-01

Full Text Available The Basel II regulatory framework significantly increased the resilience of the banking system, but proved ineffective in preventing the 2008/9 financial crisis. The subsequent introduction of Basel III aimed, inter alia, to supplement bank capital using buffers. The countercyclical buffer boosts existing minimum capital requirements when systemic risk surges are detected. Bolstering capital in favourable economic conditions cushions losses in unfavourable conditions, thereby addressing capital requirement procyclicality. This paper contains an overview of the countercyclical capital buffer and a critical discussion of its implementation as proposed in Basel III. Consequences of the buffer's introduction for South African banks are explored, and in particular, potential systemic risk indicator variables are identified that may be used by the South African Reserve Bank (SARB as early warning indicators of imminent systemic financial distress. These indicators may be of value to the SARB, which could use them in taking decisions on the build-up and release of the countercyclical buffer for South African banks.

Propagation of misfit dislocations from buffer/Si interface into Si

Science.gov (United States)

Liliental-Weber, Zuzanna [El Sobrante, CA; Maltez, Rogerio Luis [Porto Alegre, BR; Morkoc, Hadis [Richmond, VA; Xie, Jinqiao [Raleigh, VA

2011-08-30

Misfit dislocations are redirected from the buffer/Si interface and propagated to the Si substrate due to the formation of bubbles in the substrate. The buffer layer growth process is generally a thermal process that also accomplishes annealing of the Si substrate so that bubbles of the implanted ion species are formed in the Si at an appropriate distance from the buffer/Si interface so that the bubbles will not migrate to the Si surface during annealing, but are close enough to the interface so that a strain field around the bubbles will be sensed by dislocations at the buffer/Si interface and dislocations are attracted by the strain field caused by the bubbles and move into the Si substrate instead of into the buffer epi-layer. Fabrication of improved integrated devices based on GaN and Si, such as continuous wave (CW) lasers and light emitting diodes, at reduced cost is thereby enabled.

Capacity gains of buffer-aided moving relays

KAUST Repository

Zafar, Ammar

2017-03-14

This work investigates the gain due to reduction in path loss by deploying buffer-aided moving relaying. In particular, the increase in gain due to moving relays is studied for dual-hop broadcast channels and the bidirectional relay channel. It is shown that the exploited gains in these channels due to buffer-aided relaying can be enhanced by utilizing the fact that a moving relay can communicate with the terminal closest to it and store the data in the buffer and then forward the data to the intended destination when it comes in close proximity with the destination. Numerical results show that for both the considered channels the achievable rates are increased as compared to the case of stationary relays. Numerical results also show that more significant increase in performance is seen when the relay moves to-and-fro between the source and the relay.

Capacity gains of buffer-aided moving relays

KAUST Repository

Zafar, Ammar; Shaqfeh, Mohammad; Alnuweiri, Hussein; Alouini, Mohamed-Slim

2017-01-01

This work investigates the gain due to reduction in path loss by deploying buffer-aided moving relaying. In particular, the increase in gain due to moving relays is studied for dual-hop broadcast channels and the bidirectional relay channel. It is shown that the exploited gains in these channels due to buffer-aided relaying can be enhanced by utilizing the fact that a moving relay can communicate with the terminal closest to it and store the data in the buffer and then forward the data to the intended destination when it comes in close proximity with the destination. Numerical results show that for both the considered channels the achievable rates are increased as compared to the case of stationary relays. Numerical results also show that more significant increase in performance is seen when the relay moves to-and-fro between the source and the relay.

Sustained housing-type social buffering following social housing in male rats.

Science.gov (United States)

Kiyokawa, Yasushi; Ishida, Aya; Takeuchi, Yukari; Mori, Yuji

2016-05-01

In social animals, recovery from the adverse effects of distressing stimuli is promoted by subsequent cohousing with a conspecific animal(s). This phenomenon has been termed housing-type social buffering. We previously found that social housing induced housing-type social buffering in fear-conditioned male rats. This buffering took the form of attenuated conditioned hyperthermia in response to an auditory conditioned stimulus (CS). Here, we assessed whether this social buffering is sustained even if the subject is housed alone after a period of social housing. When fear-conditioned subjects were housed alone during a 48-h period between conditioning and re-exposure to the auditory CS, they exhibited conditioned hyperthermia in response to the CS. However, conditioned hyperthermia was not observed when the 12-h period of social housing began 24 and 36h after conditioning during the 48-h period. This was not the case when the 12-h period of social housing began 0 and 12h after the conditioning. These results suggest that housing-type social buffering is sustained for 12h after the 12-h period of social housing. We next considered whether increasing the duration of social housing would extend the period of social buffering. We observed social buffering of conditioned hyperthermia 24 and 48, but not 96h after a 24-h period of social housing. These results suggest that social buffering was extended when the duration of social housing was increased. Taken together, our findings indicate that housing-type social buffering is sustained after a period of social housing. Copyright © 2016 Elsevier Inc. All rights reserved.

Heuristics for the Buffer Allocation Problem with Collision Probability Using Computer Simulation

Directory of Open Access Journals (Sweden)

Eishi Chiba

2015-01-01

Full Text Available The standard manufacturing system for Flat Panel Displays (FPDs consists of a number of pieces of equipment in series. Each piece of equipment usually has a number of buffers to prevent collision between glass substrates. However, in reality, very few of these buffers seem to be used. This means that redundant buffers exist. In order to reduce cost and space necessary for manufacturing, the number of buffers should be minimized with consideration of possible collisions. In this paper, we focus on an in-line system in which each piece of equipment can have any number of buffers. In this in-line system, we present a computer simulation method for the computation of the probability of a collision occurring. Based on this method, we try to find a buffer allocation that achieves the smallest total number of buffers under an arbitrarily specified collision probability. We also implement our proposed method and present some computational results.

Surface Analysis of Railway Buffers Heads Covered with Bronze Using Laser Cladding

Directory of Open Access Journals (Sweden)

Sitarz M.

2017-06-01

Full Text Available Railway buffers during the operation are staying in almost permanent contact with each other, creating friction node in the point of contact of two railway buffer heads. In consequence of overcoming track curves, turnouts and unevenness of track, the railway buffer heads moves relative to each other causing friction, which results in its wear. When the wear is excessive, it might be a reason to withdrawn vehicle from service, it causes flattening of buffer head, and in consequence its abnormal cooperation. To avoid this phenomenon the buffer heads should be covered with graphitized grease, but this method has many disadvantages. Accordingly, it was found that it would be beneficial to cover the buffer head with bronze using laser cladding. In this article the metallographic and mechanical analysis of the newly created top layer of railway buffer head are presented. In article the results from tribological tests conducted on Amsler test bench are also presented. Based on test results described in article concluded that the layer of bronze coat on working surface of railway buffer head can be beneficial from operational point of view.

Proteins contribute insignificantly to the intrinsic buffering capacity of yeast cytoplasm

International Nuclear Information System (INIS)

Poznanski, Jaroslaw; Szczesny, Pawel; Ruszczyńska, Katarzyna; Zielenkiewicz, Piotr; Paczek, Leszek

2013-01-01

Highlights: ► We predicted buffering capacity of yeast proteome from protein abundance data. ► We measured total buffering capacity of yeast cytoplasm. ► We showed that proteins contribute insignificantly to buffering capacity. -- Abstract: Intracellular pH is maintained by a combination of the passive buffering of cytoplasmic dissociable compounds and several active systems. Over the years, a large portion of and possibly most of the cell’s intrinsic (i.e., passive non-bicarbonate) buffering effect was attributed to proteins, both in higher organisms and in yeast. This attribution was not surprising, given that the concentration of proteins with multiple protonable/deprotonable groups in the cell exceeds the concentration of free protons by a few orders of magnitude. Using data from both high-throughput experiments and in vitro laboratory experiments, we tested this concept. We assessed the buffering capacity of the yeast proteome using protein abundance data and compared it to our own titration of yeast cytoplasm. We showed that the protein contribution is less than 1% of the total intracellular buffering capacity. As confirmed with NMR measurements, inorganic phosphates play a crucial role in the process. These findings also shed a new light on the role of proteomes in maintaining intracellular pH. The contribution of proteins to the intrinsic buffering capacity is negligible, and proteins might act only as a recipient of signals for changes in pH.

An 11-bit 200 MS/s subrange SAR ADC with low-cost integrated reference buffer

Science.gov (United States)

He, Xiuju; Gu, Xian; Li, Weitao; Jiang, Hanjun; Li, Fule; Wang, Zhihua

2017-10-01

This paper presents an 11-bit 200 MS/s subrange SAR ADC with an integrated reference buffer in 65 nm CMOS. The proposed ADC employs a 3.5-bit flash ADC for coarse conversion, and a compact timing scheme at the flash/SAR boundary to speed up the conversion. The flash decision is used to control charge compensating for the reference voltage to reduce its input-dependent fluctuation. Measurement results show that the fabricated ADC has achieved significant improvement by applying the reference charge compensation. In addition, the ADC achieves a maximum signal-to-noise-and-distortion ratio of 59.3 dB at 200 MS/s. It consumes 3.91 mW from a 1.2 V supply, including the reference buffer. Project supported by the Zhongxing Telecommunication Equipment Corporation and Beijing Microelectronics Technology Institute.

Dynamics and mitigation of six pesticides in a "Wet" forest buffer zone.

Science.gov (United States)

Passeport, Elodie; Richard, Benjamin; Chaumont, Cédric; Margoum, Christelle; Liger, Lucie; Gril, Jean-Joël; Tournebize, Julien

2014-04-01

Pesticide pollution is one of the main current threats on water quality. This paper presents the potential and functioning principles of a "Wet" forest buffer zone for reducing concentrations and loads of glyphosate, isoproturon, metazachlor, azoxystrobin, epoxiconazole, and cyproconazole. A tracer injection experiment was conducted in the field in a forest buffer zone at Bray (France). A fine time-scale sampling enabled to illustrate that interactions between pesticides and forest buffer substrates (soil and organic-rich litter layer), had a retarding effect on molecule transfer. Low concentrations were observed for all pesticides at the forest buffer outlet thus demonstrating the efficiency of "Wet" forest buffer zone for pesticide dissipation. Pesticide masses injected in the forest buffer inlet directly determined concentration peaks observed at the outlet. Rapid and partially reversible adsorption was likely the major process affecting pesticide transfer for short retention times (a few hours to a few days). Remobilization of metazachlor, isoproturon, desmethylisoproturon, and AMPA was observed when non-contaminated water flows passed through the forest buffer. Our data suggest that pesticide sorption properties alone could not explain the complex reaction mechanisms that affected pesticide transfer in the forest buffer. Nevertheless, the thick layer of organic matter litter on the top of the forest soil was a key parameter, which enhanced partially reversible sorption of pesticide, thus retarded their transfer, decreased concentration peaks, and likely increased degradation of the pesticides. Consequently, to limit pesticide pollution transported by surface water, the use of already existing forest areas as buffer zones should be equally considered as the most commonly implemented grass buffer strips.

Riparian buffer zones as pesticide filters of no-till crops.

Science.gov (United States)

Aguiar, Terencio R; Bortolozo, F R; Hansel, F A; Rasera, K; Ferreira, M T

2015-07-01

Several studies have pointed to the potential benefits of riparian vegetation as buffer zones for agricultural and industrial pollutants harmful to aquatic ecosystems. However, other studies have called into question its use as an ecological filter, questioning the widths and conditions for which they are effective as a filter. In this work, we have investigated the buffering capacity of the riparian one to retain pesticides in the water-saturated zone, on 27 sites composed by riparian buffer zones with different vegetation structure (woody, shrubs, or grass vegetation) and width (12, 36, and 60 m). Five pesticides were analyzed. The effectiveness of the filtering was largely influenced by the width and vegetation type of the buffer zone. In general, decreasing pesticide removal followed in this order wood > shrubs > grass. The 60 m woody buffer zone was the most effective in the removal of all the pesticides. Only atrazine was detected in this case (0.3 μg L(-1)). Furthermore, a linear correlation (R (2) > 0.97) was observed in their removal for all compounds and buffer zones studied. Thus, preserving the woody vegetation in the riparian zone is important for watershed management and groundwater quality in the no-tillage system in temperate climate.

Stabilization of chlorfenvinphos in model dips using a buffer and a bacteriostat agent

International Nuclear Information System (INIS)

Kaposhi, C.K.M.; Mundia, M.P.; Nondo, J.C.; Mwangala, F.S.; Banda, R.

1997-01-01

The stability of chlorfenvinphos acaricide was studied in 50 L model dip tanks using a mixture of 14 C-labelled and unlabelled chlorfenvinphos with or without recharge. Calcium superphosphate fertilizer was used as buffer and to reduce the pH to below 5, while copper sulfate was used as a bacteriostat. In addition 50 g of sediment from around the dip tank was added to the vats and contents of vats were made up to 50 L using the water available at chalimbana NCSR farm. The buffer, by itself as well as in combination with copper sulfate stabilized chiorfenvinphos in the suspension. Binding with the sediment was a key factor in the reduction of chlorfenvinphos level, which was significantly reduced in all vats that contained sediments. Most of the acaricide bound to the sediment was not extractable. The pH in vats was maintained at 4.8 - 5.0 by the addition of superphosphate fertilizer, which reduced the degradation of chlorfenvinphos. Copper sulfate had no effect on the pH of the suspension and the vats treated with the bacteriostat had the lowest levels of chlorfenvinphos. TLC analysis also showed that acaricide breakdown was greater in non-buffered than in buffered vats. A metabolite, 2,4-dichloroacetophenone, was detected, although at a low level. A study of the leaching potential of chlorfenvinphos in soil columns showed that only 3% of the applied acaricide percolated through the 30 cm length of the column, while most of it remained soil-bound. A calorimetric method for measuring the concentration of chlorfenvinphos in dips was evaluated. The method is based on the reaction of the acaricide with 4-(4-nitrobenzyl) pyridine and subsequent measurement of the intensity of the colour formed with tetraethylene pentamine. The measurement was relatively accurate. (author)

Mechanical interaction buffer/backfill. Finite element calculations of the upward swelling of the buffer against both dry and saturated backfill

Energy Technology Data Exchange (ETDEWEB)

Boergesson, Lennart (Clay Technology AB, Lund (Sweden)); Hernelind, Jan (5T-Engineering AB, Vaesteraas (Sweden))

2009-10-15

The mechanical interaction between the buffer material in the deposition hole and the backfill material in the deposition tunnel is an important process in the safety assessment since the primary function of the backfill is to keep the buffer in place and not allow it to expand too much and thereby loose too much of its density and barrier properties. In order to study the upwards swelling of the buffer and the subsequent density reduction a number of finite element calculations have been performed. The calculations have been done with the FE-program Abaqus with 3D-models of a deposition hole and the deposition tunnel. In order to refine the modelling only the two extreme cases of completely un-wetted (dry) and completely water saturated (wet) backfill have been modelled. For the wet case the influence of different factors has been studied while only one calculation of the dry case has been done. The calculated upwards swelling of the buffer varied between 2 and 15 cm for the different wet cases while it was about 10 cm for the dry case. In the wet reference case the E-modulus of the block and pellets fillings was 50 MPa and 3.24 MPa respectively, the friction angle between the buffer and the rock and canister was 8.7 deg and there were no swelling pressure from the backfill. There is a strong influence of the friction angle on both the upwards swelling and the canister heave. The friction is important for preventing especially canister displacements. The unrealistic case of no friction yielded strong unacceptable influence on the buffer with an upwards swelling of 15 cm and a strong heave of 5 cm of the canister. The influence of the backfill stiffness is as expected strong. Both buffer swelling and canister heave are twice as large at the E-modulus E = 25 MPa than at the E-modulus E = 100 MPa. The influence of the stiffness of the pellets filling is not strong since there are no pellets on the floor in the model used. The influence of the swelling pressure of the

Mechanical interaction buffer/backfill. Finite element calculations of the upward swelling of the buffer against both dry and saturated backfill

International Nuclear Information System (INIS)

Boergesson, Lennart; Hernelind, Jan

2009-10-01

The mechanical interaction between the buffer material in the deposition hole and the backfill material in the deposition tunnel is an important process in the safety assessment since the primary function of the backfill is to keep the buffer in place and not allow it to expand too much and thereby loose too much of its density and barrier properties. In order to study the upwards swelling of the buffer and the subsequent density reduction a number of finite element calculations have been performed. The calculations have been done with the FE-program Abaqus with 3D-models of a deposition hole and the deposition tunnel. In order to refine the modelling only the two extreme cases of completely un-wetted (dry) and completely water saturated (wet) backfill have been modelled. For the wet case the influence of different factors has been studied while only one calculation of the dry case has been done. The calculated upwards swelling of the buffer varied between 2 and 15 cm for the different wet cases while it was about 10 cm for the dry case. In the wet reference case the E-modulus of the block and pellets fillings was 50 MPa and 3.24 MPa respectively, the friction angle between the buffer and the rock and canister was 8.7 deg and there were no swelling pressure from the backfill. There is a strong influence of the friction angle on both the upwards swelling and the canister heave. The friction is important for preventing especially canister displacements. The unrealistic case of no friction yielded strong unacceptable influence on the buffer with an upwards swelling of 15 cm and a strong heave of 5 cm of the canister. The influence of the backfill stiffness is as expected strong. Both buffer swelling and canister heave are twice as large at the E-modulus E = 25 MPa than at the E-modulus E = 100 MPa. The influence of the stiffness of the pellets filling is not strong since there are no pellets on the floor in the model used. The influence of the swelling pressure of the

Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

OpenAIRE

Wang Lan; Lin Xianzhong; Ennaoui Ahmed; Wolf Christian; Lux-Steiner Martha Ch.; Klenk Reiner

2016-01-01

We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating ...

Reprogrammable read only variable threshold transistor memory with isolated addressing buffer

Science.gov (United States)

Lodi, Robert J.

1976-01-01

A monolithic integrated circuit, fully decoded memory comprises a rectangular array of variable threshold field effect transistors organized into a plurality of multi-bit words. Binary address inputs to the memory are decoded by a field effect transistor decoder into a plurality of word selection lines each of which activates an address buffer circuit. Each address buffer circuit, in turn, drives a word line of the memory array. In accordance with the word line selected by the decoder the activated buffer circuit directs reading or writing voltages to the transistors comprising the memory words. All of the buffer circuits additionally are connected to a common terminal for clearing all of the memory transistors to a predetermined state by the application to the common terminal of a large magnitude voltage of a predetermined polarity. The address decoder, the buffer and the memory array, as well as control and input/output control and buffer field effect transistor circuits, are fabricated on a common substrate with means provided to isolate the substrate of the address buffer transistors from the remainder of the substrate so that the bulk clearing function of simultaneously placing all of the memory transistors into a predetermined state can be performed.

Chemical buffering in natural and engineered barrier systems: Thermodynamic constraints and performance assessment consequences

Energy Technology Data Exchange (ETDEWEB)

Arthur, R.C.; Wei Zhou [Monitor Scientific, LLC, Denver, CO (United States)

2000-12-01

Thermodynamic and kinetic constraints on the chemical buffering properties of natural and engineered-barrier systems are derived in this study from theoretical descriptions, incorporated in the reaction-path model, of reversible and irreversible mass transfer in multicomponent, multiphase systems. The buffering properties of such systems are conditional properties because they refer to a specific aqueous species in a system that is open with respect to a specific reactant. The solution to a mathematical statement of this concept requires evaluation of the dependence of the activity of the buffered species on incremental changes in the overall reaction-progress variable. This dependence can be represented by a truncated Taylor's series expansion, where the values of associated derivatives are calculated using finite-difference techniques and mass-balance, charge-balance and mass-action constraints. Kinetic constraints on buffering behavior can also be described if the relation between reactant flux and reaction rate is well defined. This relation is explicit for the important case of advective groundwater flow and water-rock interaction. We apply the theoretical basis of the chemical buffering concept to processes that could affect the performance of a deep geologic repository for nuclear waste. Specifically, we focus on the likelihood that an inverse relation must exist between the buffer intensity and the migration velocity of reaction fronts in systems involving advective or diffusive mass transport. A quantitative understanding of this relation would provide the basis for evaluating the potential role of chemical buffering in achieving the isolation and retardation functions, of the EBS and geosphere in a KBS-3 repository. Our preliminary evaluation of this role considers the effects of chemical buffering on the propagation velocity of a pH front in both the near- and far field. We use a geochemical modeling technique compatible with the reaction-path model

The Buffer and Backfill Handbook. Part 3: Models for calculation of processes and behaviour

Energy Technology Data Exchange (ETDEWEB)

Pusch, Roland [Geodevelopment AB, Lund (Sweden)

2003-01-15

nature. They are coupled to other processes and affected by various restrictions such as limited access to water and transient interaction with dissolved species. This makes the issue of coupled models very important but almost all the models and codes that are being used in predicting the behaviour of buffers and backfills in a repository are simplified and incomplete with respect to the hydrothermal processes. This is because of the lack of understanding of the involved physico-chemical mechanisms, for which consideration of the behaviour of the clay on the microstructural level is required. Chapter 3 deals with microstructural issues focusing on particle interaction and void distribution in buffers and backfills with special respect to swelling pressure and permeation of fluids and gas. Chapter 4 deals with heat transport in fully and partly water saturated buffer clays. It includes mathematical formulation of empirically deduced material models of heat conductivity and gives examples of how this quantity can be evaluated from laboratory experiments. Chapter 5 deals with flow of water in liquid and vapour form in fully and partly water saturated buffers and backfills. The presented material models are intended for practical use and imply that potential theory in the form of Navier/Stoke's laws for analytical solution or numerical methods are valid. Chapter 6 gives the basis of currently used material models for anion and cation diffusion through smectitic soil. Complexation may cause considerable deviation from theoretically derived migration rates and only diffusive transport of species that do not undergo chemical reactions is treated here. Focus is on outlining the formulation of theoretical models for evaluation of diffusion coefficients from controlled experiments. As for water transport, the solution of practical 2 and 3D problems is made by use of potential theory, applying analytical or numerical techniques, which are not treated here. Chapter 7 deals

Protein brownian rotation at the glass transition temperature of a freeze-concentrated buffer probed by superparamagnetic nanoparticles.

Science.gov (United States)

Eloi, J-C; Okuda, M; Jones, S E Ward; Schwarzacher, W

2013-06-18

For applications from food science to the freeze-thawing of proteins it is important to understand the often complex freezing behavior of solutions of biomolecules. Here we use a magnetic method to monitor the Brownian rotation of a quasi-spherical cage-shaped protein, apoferritin, approaching the glass transition Tg in a freeze-concentrated buffer (Tris-HCl). The protein incorporates a synthetic magnetic nanoparticle (Co-doped Fe3O4 (magnetite)). We use the magnetic signal from the nanoparticles to monitor the protein orientation. As T decreases toward Tg of the buffer solution the protein's rotational relaxation time increases exponentially, taking values in the range from a few seconds up to thousands of seconds, i.e., orders of magnitude greater than usually accessed, e.g., by NMR. The longest relaxation times measured correspond to estimated viscosities >2 MPa s. As well as being a means to study low-temperature, high-viscosity environments, our method provides evidence that, for the cooling protocol used, the following applies: 1), the concentration of the freeze-concentrated buffer at Tg is independent of its initial concentration; 2), little protein adsorption takes place at the interface between ice and buffer; and 3), the protein is free to rotate even at temperatures as low as 207 K. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Reconnecting tile drainage to riparian buffer hydrology for enhanced nitrate removal.

Science.gov (United States)

Jaynes, D B; Isenhart, T M

2014-03-01

Riparian buffers are a proven practice for removing NO from overland flow and shallow groundwater. However, in landscapes with artificial subsurface (tile) drainage, most of the subsurface flow leaving fields is passed through the buffers in drainage pipes, leaving little opportunity for NO removal. We investigated the feasibility of re-routing a fraction of field tile drainage as subsurface flow through a riparian buffer for increasing NO removal. We intercepted an existing field tile outlet draining a 10.1-ha area of a row-cropped field in central Iowa and re-routed a fraction of the discharge as subsurface flow along 335 m of an existing riparian buffer. Tile drainage from the field was infiltrated through a perforated pipe installed 75 cm below the surface by maintaining a constant head in the pipe at a control box installed in-line with the existing field outlet. During 2 yr, >18,000 m (55%) of the total flow from the tile outlet was redirected as infiltration within the riparian buffer. The redirected water seeped through the 60-m-wide buffer, raising the water table approximately 35 cm. The redirected tile flow contained 228 kg of NO. On the basis of the strong decrease in NO concentrations within the shallow groundwater across the buffer, we hypothesize that the NO did not enter the stream but was removed within the buffer by plant uptake, microbial immobilization, or denitrification. Redirecting tile drainage as subsurface flow through a riparian buffer increased its NO removal benefit and is a promising management practice to improve surface water quality within tile-drained landscapes. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effect of buffer at nanoscale molecular recognition interfaces - electrostatic binding of biological polyanions.

Science.gov (United States)

Rodrigo, Ana C; Laurini, Erik; Vieira, Vânia M P; Pricl, Sabrina; Smith, David K

2017-10-19

We investigate the impact of an over-looked component on molecular recognition in water-buffer. The binding of a cationic dye to biological polyanion heparin is shown by isothermal calorimetry to depend on buffer (Tris-HCl > HEPES > PBS). The heparin binding of self-assembled multivalent (SAMul) cationic micelles is even more buffer dependent. Multivalent electrostatic molecular recognition is buffer dependent as a result of competitive interactions between the cationic binding interface and anions present in the buffer.

Optimal Maintenance of a Production System with Intermediate Buffers

Directory of Open Access Journals (Sweden)

Constantinos C. Karamatsoukis

2012-01-01

Full Text Available We consider a production-inventory system that consists of an input-generating installation, a production unit and L intermediate buffers. It is assumed that the installation transfers the raw material to buffer and the production unit pulls the raw material from buffer We consider the problem of the optimal preventive maintenance of the installation if the installation deteriorates stochastically with usage and the production unit is always in operative condition. We also consider the problem of the optimal preventive maintenance of the production unit if the production unit deteriorates stochastically with usage and the installation is always in operative condition. Under a suitable cost structure and for given contents of the buffers, it is proved that the average-cost optimal policy for the first (second problem initiates a preventive maintenance of the installation (production unit if and only if the degree of deterioration of the installation (production unit exceeds some critical level. Numerical results are presented for both problems.

Rare earth zirconium oxide buffer layers on metal substrates

Science.gov (United States)

Williams, Robert K.; Paranthaman, Mariappan; Chirayil, Thomas G.; Lee, Dominic F.; Goyal, Amit; Feenstra, Roeland

2001-01-01

A laminate article comprises a substrate and a biaxially textured (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer over the substrate, wherein 0layer can be deposited using sol-gel or metal-organic decomposition. The laminate article can include a layer of YBCO over the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer. A layer of CeO.sub.2 between the YBCO layer and the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer can also be include. Further included can be a layer of YSZ between the CeO.sub.2 layer and the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer. The substrate can be a biaxially textured metal, such as nickel. A method of forming the laminate article is also disclosed.

A read-out buffer prototype for ATLAS high level triggers

CERN Document Server

Calvet, D; Huet, M; Le Dû, P; Mandjavidze, I D; Mur, M

2000-01-01

Read-Out Buffers are critical components in the dataflow chain of the ATLAS Trigger/DAQ system. At up to 75 kHz, after each Level-1 trigger accept signal, these devices receive and store digitized data from groups of front-end electronic channels. Several Read-Out Buffers are grouped to form a Read-Out Buffer Complex that acts as a data server for the High Level Triggers selection algorithms and for the final data collection system. This paper describes a functional prototype of a Read-Out Buffer based on a custom made PCI mezzanine card that is designed to accept input data at up to 160 MB/s, to store up to 8 MB of data and to distribute data chunks at the desired request rate. We describe the hardware of the card that is based on an Intel I960 processor and CPLDs. We present the integration of several of these cards in a Read-Out Buffer Complex. We measure various performance figures and we discuss to which extent these can fulfill ATLAS needs. 5 Refs.

The use of 0.01M phosphate buffered saline as detection buffer for ...

African Journals Online (AJOL)

Insufficient supply of manufacture's buffers/diluents in relation to the number of strips per kit has been found to have negative impact on patients' results. Some laboratories personnel tend to use diluents from other rapid tests manufacturers such as Bioline, Unigold as well as malaria rapid diagnostic test (MRDT). This study ...

Investigation on performance of all optical buffer with large dynamical delay time based on cascaded double loop optical buffers

International Nuclear Information System (INIS)

Yong-Jun, Wang; Xiang-Jun, Xin; Xiao-Lei, Zhang; Chong-Qing, Wu; Kuang-Lu, Yu

2010-01-01

Optical buffers are critical for optical signal processing in future optical packet-switched networks. In this paper, a theoretical study as well as an experimental demonstration on a new optical buffer with large dynamical delay time is carried out based on cascaded double loop optical buffers (DLOBs). It is found that pulse distortion can be restrained by a negative optical control mode when the optical packet is in the loop. Noise analysis indicates that it is feasible to realise a large variable delay range by cascaded DLOBs. These conclusions are validated by the experiment system with 4-stage cascaded DLOBs. Both the theoretical simulations and the experimental results indicate that a large delay range of 1–9999 times the basic delay unit and a fine granularity of 25 ns can be achieved by the cascaded DLOBs. The performance of the cascaded DLOBs is suitable for the all optical networks. (classical areas of phenomenology)

Investigating the episodic buffer

Directory of Open Access Journals (Sweden)

Alan Baddeley

2010-10-01

Full Text Available A brief account is presented of the three-component working memory model proposed by Baddeley and Hitch. This is followed by an account of some of the problems it encountered in explaining how information from different subsystems with different codes could be combined, and how it was capable of communicating with long-term memory. In order to account for these, a fourth component was proposed, the episodic buffer. This was assumed to be a multidimensional store of limited capacity that can be accessed through conscious awareness. In an attempt to test and develop the concept, a series of experiments have explored the role of working memory in the binding of visual features into objects and verbal sequences into remembered sentences. The experiments use a dual task paradigm to investigate the role of the various subcomponents of working memory in binding. In contrast to our initial assumption, the episodic buffer appears to be a passive store, capable of storing bound features and making them available to conscious awareness, but not itself responsible for the process of binding.

Analysis of the effect of vibrations on the bentonite buffer in the canister hole

International Nuclear Information System (INIS)

Jonsson, Martin; Hakami, Hossein; Ekneligoda, Thushan

2009-09-01

During the construction of a final repository for spent nuclear fuel in crystalline rock, blasting activities in certain deposition tunnels will occur at the same time as the deposition of canisters containing the waste is going on in another adjacent access tunnel. In fact, the deposition consists of several stages after the drilling of the deposition hole. The most vulnerable stage from a vibration point of view is when the bentonite buffer is placed in the deposition hole but the canister has not been placed yet. During this stage, a hollow column of bentonite blocks remains free to vibrate inside the deposition hole. The goal of this study was to investigate the displacement of the bentonite blocks when exposed to the highest vibration level that can be expected during the drill and blast operations. In order to investigate this, a three dimensional model in 3DEC, capable of capturing the dynamic behaviour of the bentonite buffer was set up. To define the vibration levels, which serve as input data for the 3DEC model, an extensive analysis of the recorded vibrations from the TASQ - tunnel was carried out. For this purpose, an upper expected vibration limit was defined. This was done outgoing from the fact that the planned charging for the construction of the geological repository will lie in the interval 2 to 4 kg. Furthermore, at the first stage for this study, it was decided that the vibration should be conservatively evaluated for 30 m distance. Using these data, it was concluded that the maximum vibration level that can be expected will be approximately 60 mm/s. After simplifying the vibration signal, a sinusoidal wave with the amplitude 60 mm/s was applied at the bottom of the column and it was assumed that the vibrations only affect the bentonite buffer in one direction (horizontal direction). From this simulation, it was concluded that hardly any displacements occurred. However, when applying the same sinusoidal wave both in the horizontal and the

Protective buffering and emotional desynchrony among spousal caregivers of cancer patients.

Science.gov (United States)

Langer, Shelby L; Rudd, Michael E; Syrjala, Karen L

2007-09-01

To examine protective buffering and emotional desynchrony among spousal caregivers of cancer survivors. Repeated measures; 42 caregivers engaged in 2 videotaped, oral emotional expression exercises: 1 in the presence of their patient and 1 in the absence of their patient. Felt emotion (self-report) and expressed emotion (lexical expression or words uttered and coder-derived facial expression). Other measures assessed mental and physical health, dyadic satisfaction, and dispositional emotional inhibition. Protective buffering differed by communicative channel (lexical vs. facial). Caregivers' facial expressions were more positive when the patient was present versus absent. In contrast, the valence of caregivers' words did not differ per patient presence. Facial protective buffering was unrelated to health and dyadic outcomes. Lexical protective buffering was inversely related to both caregiver and patient marital satisfaction. Dispositional emotional inhibition was inversely related to caregiver mental health and marital satisfaction. Desynchrony occurred when the patient was present but was counter to prediction; felt emotion was more positive than expressed emotion. Results provide behavioral evidence of facial protective buffering. To the extent that lexical buffering occurs, it poses a dyadic risk, and chronic inhibition poses both psychological and dyadic risks. Future research is needed to refine the operational definition of desynchrony and to examine the biopsychosocial sequelae of buffering. (PsycINFO Database Record (c) 2007 APA, all rights reserved).

The effect of the MgO buffer layer thickness on magnetic anisotropy in MgO/Fe/Cr/MgO buffer/MgO(001)

Energy Technology Data Exchange (ETDEWEB)

Kozioł-Rachwał, Anna, E-mail: a.koziolrachwal@aist.go.jp [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Nozaki, Takayuki; Zayets, Vadym; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Suzuki, Yoshishige [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

2016-08-28

The relationship between the magnetic properties and MgO buffer layer thickness d was studied in epitaxial MgO/Fe(t)/Cr/MgO(d) layers grown on MgO(001) substrate in which the Fe thickness t ranged from 0.4 nm to 1.1 nm. For 0.4 nm ≤ t ≤ 0.7 nm, a non-monotonic coercivity dependence on the MgO buffer thickness was shown by perpendicular magneto-optic Kerr effect magnetometry. For thicker Fe films, an increase in the buffer layer thickness resulted in a spin reorientation transition from perpendicular to the in-plane magnetization direction. Possible origins of these unusual behaviors were discussed in terms of the suppression of carbon contamination at the Fe surface and changes in the magnetoelastic anisotropy in the system. These results illustrate a method to control magnetic anisotropy in MgO/Fe/Cr/MgO(d) via an appropriate choice of MgO buffer layer thickness d.

Spectroscopical determination of impurities in nuclear graphite

International Nuclear Information System (INIS)

Lordello, A.R.; Tognini, R.P.

1975-01-01

A spectrochemical method for the direct determination of B, Cd, Si, Hg, Fe, Mg, Mn, Cr, Ni, Al, Mo, Ti, Sr, Na, Zn, and As in nuclear grade graphite is described. A 9:1 ratio of graphite to copper difluoride is used in the preparation of samples and standards. The excitation is carried out in a d-c at 10 amperes. The copper fluoride used as spectrographic buffer serves to increase the volatilization rate of the impurities and to diminish the differences in the nature of the analytical and calibration samples. The relative standard deviations for the determination of the 16 trace elements, except Sr, Fe, Cd, Al and Si, are in the range of 8 - 20% in their appropriate calibration levels. For the latter five elements they are approximately 20-40%

Nanosecond Nd-YAG laser induced plasma emission characteristics in low pressure CO{sub 2} ambient gas for spectrochemical application on Mars

Energy Technology Data Exchange (ETDEWEB)

Lie, Zener Sukra; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Kagawa, Kiichiro [Fukui Science Education Academy, Takagi Chuou 2 choume, Fukui 910-0804 (Japan); Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia)

2015-08-28

An experimental study is conducted on the possibility and viability of performing spectrochemical analysis of carbon and other elements in trace amount in Mars, in particular, the clean detection of C, which is indispensible for tracking the sign of life in Mars. For this study, a nanosecond Nd-YAG laser is employed to generate plasma emission from a pure copper target in CO{sub 2} ambient gas of reduced pressure simulating the atmospheric condition of Mars. It is shown that the same shock wave excitation mechanism also works this case while exhibiting remarkably long cooling stage. The highest Cu emission intensities induced by 4 mJ laser ablation energy is attained in 600 Pa CO{sub 2} ambient gas. Meanwhile the considerably weaker carbon emission from the CO{sub 2} gas appears relatively featureless over the entire range of pressure variation, posing a serious problem for sensitive trace analysis of C contained in a solid sample. Our time resolved intensity measurement nevertheless reveals earlier appearance of C emission from the CO{sub 2} gas with a limited duration from 50 ns to 400 ns after the laser irradiation, well before the initial appearance of the long lasting C emission from the solid target at about 1 μs, due to the different C-releasing processes from their different host materials. The unwanted C emission from the ambient gas can thus be eliminated from the detected spectrum by a proper time gated detection window. The excellent spectra of carbon, aluminum, calcium, sodium, hydrogen, and oxygen obtained from an agate sample are presented to further demonstrate and verify merit of this special time gated LIBS using CO{sub 2} ambient gas and suggesting its viability for broad ranging in-situ applications in Mars.

Use of bicarbonate buffer systems for dissolution characterization of enteric-coated proton pump inhibitor tablets.

Science.gov (United States)

Shibata, Hiroko; Yoshida, Hiroyuki; Izutsu, Ken-Ichi; Goda, Yukihiro

2016-04-01

The aim of this study was to assess the effects of buffer systems (bicarbonate or phosphate at different concentrations) on the in vitro dissolution profiles of commercially available enteric-coated tablets. In vitro dissolution tests were conducted using an USP apparatus II on 12 enteric-coated omeprazole and rabeprazole tablets, including innovator and generic formulations in phosphate buffers, bicarbonate buffers and a media modified Hanks (mHanks) buffer. Both omeprazole and rabeprazole tablets showed similar dissolution profiles among products in the compendial phosphate buffer system. However, there were large differences between products in dissolution lag time in mHanks buffer and bicarbonate buffers. All formulations showed longer dissolution lag times at lower concentrations of bicarbonate or phosphate buffers. The dissolution rank order of each formulation differed between mHanks buffer and bicarbonate buffers. A rabeprazole formulation coated with a methacrylic acid copolymer showed the shortest lag time in the high concentration bicarbonate buffer, suggesting varied responses depending on the coating layer and buffer components. Use of multiple dissolution media during in vitro testing, including high concentration bicarbonate buffer, would contribute to the efficient design of enteric-coated drug formulations. © 2016 Royal Pharmaceutical Society, Journal of Pharmacy and Pharmacology.

Simulation study on single event burnout in linear doping buffer layer engineered power VDMOSFET

International Nuclear Information System (INIS)

Jia Yunpeng; Su Hongyuan; Hu Dongqing; Wu Yu; Jin Rui

2016-01-01

The addition of a buffer layer can improve the device's secondary breakdown voltage, thus, improving the single event burnout (SEB) threshold voltage. In this paper, an N type linear doping buffer layer is proposed. According to quasi-stationary avalanche simulation and heavy ion beam simulation, the results show that an optimized linear doping buffer layer is critical. As SEB is induced by heavy ions impacting, the electric field of an optimized linear doping buffer device is much lower than that with an optimized constant doping buffer layer at a given buffer layer thickness and the same biasing voltages. Secondary breakdown voltage and the parasitic bipolar turn-on current are much higher than those with the optimized constant doping buffer layer. So the linear buffer layer is more advantageous to improving the device's SEB performance. (paper)

The role of the episodic buffer in working memory for language processing.

Science.gov (United States)

Rudner, Mary; Rönnberg, Jerker

2008-03-01

A body of work has accumulated to show that the cognitive process of binding information from different mnemonic and sensory sources as well as in different linguistic modalities can be fractionated from general executive functions in working memory both functionally and neurally. This process has been defined in terms of the episodic buffer (Baddeley in Trends Cogn Sci 4(11):417-423, 2000). This paper considers behavioural, neuropsychological and neuroimaging data that elucidate the role of the episodic buffer in language processing. We argue that the episodic buffer seems to be truly multimodal in function and that while formation of unitary multidimensional representations in the episodic buffer seems to engage posterior neural networks, maintenance of such representations is supported by frontal networks. Although, the episodic buffer is not necessarily supported by executive processes and seems to be supported by different neural networks, it may operate in tandem with the central executive during effortful language processing. There is also evidence to suggest engagement of the phonological loop during buffer processing. The hippocampus seems to play a role in formation but not maintenance of representations in the episodic buffer of working memory.

Assessment and preliminary design of an energy buffer for regenerative braking in electric vehicles

Science.gov (United States)

Buchholz, R.; Mathur, A. K.

1979-01-01

Energy buffer systems, capable of storing the vehicle energy during braking and reusing this stored energy during acceleration, were examined. Some of these buffer systems when incorporated in an electric vehicle would result in an improvement in the performance and range under stop and go driving conditions. Buffer systems considered included flywheels, hydropneumatic, pneumatic, spring, and regenerative braking. Buffer ranking and rating criteria were established. Buffer systems were rated based on predicted range improvements, consumer acceptance, driveability, safety, reliability and durability, and initial and life cycle costs. A hydropneumatic buffer system was selected.

Despite Buffers, Experimental Forest Clearcuts Impact Amphibian Body Size and Biomass.

Science.gov (United States)

Veysey Powell, Jessica S; Babbitt, Kimberly J

2015-01-01

Forest buffers are a primary tool used to protect wetland-dependent wildlife. Though implemented widely, buffer efficacy is untested for most amphibian species. Consequently, it remains unclear whether buffers are sufficient for maintaining amphibian populations and if so, how wide buffers should be. We present evidence from a six-year, landscape-scale experiment testing the impacts of clearcutting, buffer width, and hydroperiod on body size and condition and biomass of breeding adults for two amphibian species at 11 vernal pools in the northeastern United States. We randomly assigned treatments (i.e., reference, 100m buffer, 30m buffer) across pools, clearcut to create buffers, and captured all spotted salamanders and wood frogs. Clearcuts strongly and negatively impacted size, condition, and biomass, but wider buffers mitigated effect magnitude and duration. Among recaptured individuals, for example, 30m-treatment salamanders were predicted to be about 9.5 mm shorter than, while 100m-treatment salamanders did not differ in length from, reference-treatment salamanders. Similarly, among recaptured frogs, mean length in the 30m treatment was predicted to decrease by about 1 mm/year, while in the 100m and reference treatments, length was time-invariant. Some, but not all, metrics recovered with time. For example, female new-captured and recaptured salamanders were predicted, respectively and on average, to weigh 4.5 and 7 g less in the 30m versus reference treatment right after the cut. While recaptured-female mass was predicted to recover by 9.5 years post-cut, new-captured-female mass did not recover. Hydroperiod was an important mediator: in the 100m treatment, cutting predominately affected pools that were stressed hydrologically. Overall, salamanders and female frogs were impacted more than male frogs. Our results highlight the importance of individualized metrics like body size, which can reveal sublethal effects and illuminate mechanisms by which habitat

Despite Buffers, Experimental Forest Clearcuts Impact Amphibian Body Size and Biomass.

Directory of Open Access Journals (Sweden)

Jessica S Veysey Powell

Full Text Available Forest buffers are a primary tool used to protect wetland-dependent wildlife. Though implemented widely, buffer efficacy is untested for most amphibian species. Consequently, it remains unclear whether buffers are sufficient for maintaining amphibian populations and if so, how wide buffers should be. We present evidence from a six-year, landscape-scale experiment testing the impacts of clearcutting, buffer width, and hydroperiod on body size and condition and biomass of breeding adults for two amphibian species at 11 vernal pools in the northeastern United States. We randomly assigned treatments (i.e., reference, 100m buffer, 30m buffer across pools, clearcut to create buffers, and captured all spotted salamanders and wood frogs. Clearcuts strongly and negatively impacted size, condition, and biomass, but wider buffers mitigated effect magnitude and duration. Among recaptured individuals, for example, 30m-treatment salamanders were predicted to be about 9.5 mm shorter than, while 100m-treatment salamanders did not differ in length from, reference-treatment salamanders. Similarly, among recaptured frogs, mean length in the 30m treatment was predicted to decrease by about 1 mm/year, while in the 100m and reference treatments, length was time-invariant. Some, but not all, metrics recovered with time. For example, female new-captured and recaptured salamanders were predicted, respectively and on average, to weigh 4.5 and 7 g less in the 30m versus reference treatment right after the cut. While recaptured-female mass was predicted to recover by 9.5 years post-cut, new-captured-female mass did not recover. Hydroperiod was an important mediator: in the 100m treatment, cutting predominately affected pools that were stressed hydrologically. Overall, salamanders and female frogs were impacted more than male frogs. Our results highlight the importance of individualized metrics like body size, which can reveal sublethal effects and illuminate mechanisms by

A Capital Adequacy Buffer Model

NARCIS (Netherlands)

D.E. Allen (David); M.J. McAleer (Michael); R.J. Powell (Robert); A.K. Singh (Abhay)

2013-01-01

markdownabstract__Abstract__ In this paper, we develop a new capital adequacy buffer model (CABM) which is sensitive to dynamic economic circumstances. The model, which measures additional bank capital required to compensate for fluctuating credit risk, is a novel combination of the Merton

Fatigue of graphite/epoxy buffer strip panels with center cracks

Science.gov (United States)

Bigelow, C. A.

1985-01-01

The effects of fatigue loading on the behavior of graphite/epoxy panels with either S-Glass or Kevlar-49 buffer strips is studied. Buffer strip panels are fatigued and tested in tension to measure their residual strength with crack-like damage. Panels are made with 45/0/-45/90 sub 2s layup with either S-Glass or Kevlar-49 buffer strip material. The buffer strips are parallel to the loading direction and made by replacing narrow strips of the 0-degree graphite plies with strips of either 0-degree S-Glass/epoxy or Kevlar-49/epoxy on a one-for-one basis. The panels are subjected to a fatigue loading spectrum MINITWIST, the shortened version of the standardized load program for the wing lower surface of a transport aircraft. Two levels of maximum strain are used in the spectrum with three durations of the fatigue spectrum. One group of panels is preloaded prior to the application of the fatigue cycling. The preload consists of statistically loading the spectrum in tension until the crack-tip damage zone reaches the ajacent buffer strips. After fatigue loading, all specimens are statistically loaded in tension to failure to determine their residual strengths.

Carbon dioxide dissociation and buffering in chicken blood during development.

Science.gov (United States)

Tazawa, H; Piiper, J

1984-07-01

Carbon dioxide dissociation curves of oxygenated and deoxygenated bloods, the Haldane effect, the buffer value and other blood and true plasma buffering indices, O2 capacity and hematocrit were determined in bloods withdrawn from chicks before, during and after hatching and 8-month-old hens. Blood CO2 dissociation curves shifted upwards in the developing embryo till pipping, and moved downwards after pipping and hatching. In accordance with the position of the CO2 dissociation curves, the true plasma bicarbonate and red cell CO2 standardized to PCO2 = 40 torr changed. The Haldane factor at standard PCO2 increased from 0.12-0.13 on days 10-14 of incubation to 0.34 in young hens. The buffering power changed in parallel with O2 capacity and hematocrit, increasing steadily during incubation, dropping at hatching and then increasing again to the adult value. The observed changes in the CO2 dissociation curves and buffering variables during the development enable the chick to minimize the changes in the acid-base status and are favorable for coping with the increasing demand for CO2 transport and buffering of the developing bird.

Magnetic properties of Pr-Fe-B thick-film magnets deposited on Si substrates with glass buffer layer

Science.gov (United States)

Nakano, M.; Kurosaki, A.; Kondo, H.; Shimizu, D.; Yamaguchi, Y.; Yamashita, A.; Yanai, T.; Fukunaga, H.

2018-05-01

In order to improve the magnetic properties of PLD-made Pr-Fe-B thick-film magnets deposited on Si substrates, an adoption of a glass buffer layer was carried out. The glass layer could be fabricated under the deposition rate of approximately 70 μm/h on a Si substrate using a Nd-YAG pulse laser in the vacuum atmosphere. The use of the layer enabled us to reduce the Pr content without a mechanical destruction and enhance (BH)max value by approximately 20 kJ/m3 compared with the average value of non-buffer layered Pr-Fe-B films with almost the same thickness. It is also considered that the layer is also effective to apply a micro magnetization to the films deposited on Si ones.

Analysis of microbial populations, denitrification, and nitrous oxide production in riparian buffers

Science.gov (United States)

Riparian buffers are used extensively to protect water bodies from nonpoint source nitrogen pollution. However there is relatively little information on the impact of these buffers on production of nitrous oxide (N2O). In this study, we assessed nitrous oxide production in riparian buffers of the so...

Exposure to buffer solution alters tendon hydration and mechanics.

Science.gov (United States)

Safa, Babak N; Meadows, Kyle D; Szczesny, Spencer E; Elliott, Dawn M

2017-08-16

A buffer solution is often used to maintain tissue hydration during mechanical testing. The most commonly used buffer solution is a physiological concentration of phosphate buffered saline (PBS); however, PBS increases the tissue's water content and decreases its tensile stiffness. In addition, solutes from the buffer can diffuse into the tissue and interact with its structure and mechanics. These bathing solution effects can confound the outcome and interpretation of mechanical tests. Potential bathing solution artifacts, including solute diffusion, and their effect on mechanical properties, are not well understood. The objective of this study was to measure the effects of long-term exposure of rat tail tendon fascicles to several concentrations (0.9-25%) of NaCl, sucrose, polyethylene glycol (PEG), and SPEG (NaCl+PEG) solutions on water content, solute diffusion, and mechanical properties. We found that with an increase in solute concentration the apparent water content decreased for all solution types. Solutes diffused into the tissue for NaCl and sucrose, however, no solute diffusion was observed for PEG or SPEG. The mechanical properties changed for both NaCl solutions, in particular after long-term (8h) incubation the modulus and equilibrium stress decreased compared to short-term (15min) for 25% NaCl, and the cross sectional area increased for 0.9% NaCl. However, the mechanical properties were unchanged for both PEG and SPEG except for minor alterations in stress relaxation parameters. This study shows that NaCl and sucrose buffer solutions are not suitable for long-term mechanical tests. We therefore propose using PEG or SPEG as alternative buffer solutions that after long-term incubation can maintain tissue hydration without solute diffusion and produce a consistent mechanical response. Copyright © 2017 Elsevier Ltd. All rights reserved.

Buffer management in wireless full-duplex systems

KAUST Repository

Bouacida, Nader

2015-10-19

Wireless full-duplex radios can simultaneously transmit and receive using the same frequency. In theory, this can double the throughput. In fact, there is only little work addressing aspects other than throughput gains in full-duplex systems. Over-buffering in today\\'s networks or the so-called “bufferbloat” phenomenon creates excessive end-to-end delays resulting in network performance degradation. Our analysis shows that full-duplex systems may suffer from high latency caused by bloated buffers. In this paper, we address the problem of buffer management in full-duplex networks by using Wireless Queue Management (WQM), which is an active queue management technique for wireless networks. Our solution is based on Relay Full-Duplex MAC (RFD-MAC), an asynchronous media access control protocol designed for relay full-duplexing. We compare the performance of WQM in full-duplex environment to Drop Tail mechanism over various scenarios. Our solution reduces the end-to-end delay by two orders of magnitude while achieving similar throughput in most of the cases.

Optimizing the HLT Buffer Strategy with Monte Carlo Simulations

CERN Document Server

AUTHOR|(CDS)2266763

2017-01-01

This project aims to optimize the strategy of utilizing the disk buffer for the High Level Trigger (HLT) of the LHCb experiment with the help of Monte-Carlo simulations. A method is developed, which simulates the Event Filter Farm (EFF) -- a computing cluster for the High Level Trigger -- as a compound of nodes with different performance properties. In this way, the behavior of the computing farm can be analyzed at a deeper level than before. It is demonstrated that the current operating strategy might be improved when data taking is reaching a mid-year scheduled stop or the year-end technical stop. The processing time of the buffered data can be lowered by distributing the detector data according to the processing power of the nodes instead of the relative disk size as long as the occupancy level of the buffer is low enough. Moreover, this ensures that data taken and stored on the buffer at the same time is processed by different nodes nearly simultaneously, which reduces load on the infrastructure.

Buffer layers for REBCO films for use in superconducting devices

Science.gov (United States)

Goyal, Amit; Wee, Sung-Hun

2014-06-10

A superconducting article includes a substrate having a biaxially textured surface. A biaxially textured buffer layer, which can be a cap layer, is supported by the substrate. The buffer layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different transition metal cations. A biaxially textured superconductor layer is deposited so as to be supported by the buffer layer. A method of making a superconducting article is also disclosed.

Optically pumped alkali laser and amplifier using helium-3 buffer gas

Science.gov (United States)

Beach, Raymond J.; Page, Ralph; Soules, Thomas; Stappaerts, Eddy; Wu, Sheldon Shao Quan

2010-09-28

In one embodiment, a laser oscillator is provided comprising an optical cavity, the optical cavity including a gain medium including an alkali vapor and a buffer gas, the buffer gas including .sup.3He gas, wherein if .sup.4He gas is also present in the buffer gas, the ratio of the concentration of the .sup.3He gas to the .sup.4He gas is greater than 1.37.times.10.sup.-6. Additionally, an optical excitation source is provided. Furthermore, the laser oscillator is capable of outputting radiation at a first frequency. In another embodiment, an apparatus is provided comprising a gain medium including an alkali vapor and a buffer gas including .sup.3He gas, wherein if .sup.4He gas is also present in the buffer gas, the ratio of the concentration of the .sup.3He gas to the .sup.4He gas is greater than 1.37.times.10.sup.-6. Other embodiments are also disclosed.

Buffer Strips for Riparian Zone Management

National Research Council Canada - National Science Library

1991-01-01

This study provides a review of technical literature concerning the width of riparian buffer strips needed to protect water quality and maintain other important values provided by riparian ecosystem...

Model analysis of riparian buffer effectiveness for reducing nutrient inputs to streams in agricultural landscapes

Science.gov (United States)

McKane, R. B.; M, S.; F, P.; Kwiatkowski, B. L.; Rastetter, E. B.

2006-12-01

Federal and state agencies responsible for protecting water quality rely mainly on statistically-based methods to assess and manage risks to the nation's streams, lakes and estuaries. Although statistical approaches provide valuable information on current trends in water quality, process-based simulation models are essential for understanding and forecasting how changes in human activities across complex landscapes impact the transport of nutrients and contaminants to surface waters. To address this need, we developed a broadly applicable, process-based watershed simulator that links a spatially-explicit hydrologic model and a terrestrial biogeochemistry model (MEL). See Stieglitz et al. and Pan et al., this meeting, for details on the design and verification of this simulator. Here we apply the watershed simulator to a generalized agricultural setting to demonstrate its potential for informing policy and management decisions concerning water quality. This demonstration specifically explores the effectiveness of riparian buffers for reducing the transport of nitrogenous fertilizers from agricultural fields to streams. The interaction of hydrologic and biogeochemical processes represented in our simulator allows several important questions to be addressed. (1) For a range of upland fertilization rates, to what extent do riparian buffers reduce nitrogen inputs to streams? (2) How does buffer effectiveness change over time as the plant-soil system approaches N-saturation? (3) How can buffers be managed to increase their effectiveness, e.g., through periodic harvest and replanting? The model results illustrate that, while the answers to these questions depend to some extent on site factors (climatic regime, soil properties and vegetation type), in all cases riparian buffers have a limited capacity to reduce nitrogen inputs to streams where fertilization rates approach those typically used for intensive agriculture (e.g., 200 kg N per ha per year for corn in the U

Development and application of a green-chemistry solution deposition technique for buffer layer coating on cube-textured metal substrates in view of further deposition of rare-earth based superconductors

DEFF Research Database (Denmark)

Pallewatta, Pallewatta G A P

which consist of YBCO superconducting coatings on cube-textured Ni based alloy tapes.  Before the epitaxial deposition this superconducting layer, a buffer layer is applied on the metal substrate as a diffusion barrier which is also required to transfer the strong texture of the underlying substrate......, allowing the epitaxial growth of the superconducting layer. State-of-the-art coated conductor hetero structures are mainly based on CeO2 based buffer stacks that consist of a sequence of several different buffer layers. Buffer layers deposited by continuous chemical deposition techniques, which...... is expected to be very advantageous in reel-to-reel applications. The thickness of these SrTiO3 monolayers was large enough to stop the nickel and copper diffusion from the Cu/Ni substrate. Hence, the developed high quality buffer layers are expected to be acting as efficient diffusion barriers and also...

Molecular Buffers Permit Sensitivity Tuning and Inversion of Riboswitch Signals

DEFF Research Database (Denmark)

Rugbjerg, Peter; Genee, Hans Jasper; Jensen, Kristian

2016-01-01

transcription factor, while interacting DNA-binding domains mediate the transduction of signal and form an interacting molecular buffer. The molecular buffer system enables modular signal inversion through integration with repressor modules. Further, tuning of input sensitivity was achieved through perturbation...

Success and failure with phthalate buffers in capillary zone electrophoresis

NARCIS (Netherlands)

Bocek, P.; Gebauer, P.; Beckers, J.L.

2001-01-01

Phthalate buffers are currently used in capillary electrophoresis as robust electrolyte systems for indirect detection. This contribution demonstrates that these buffers show regularly not only successful regions of mobilities of analytes (sample window) but also regions of failure where the

"cAMP sponge": a buffer for cyclic adenosine 3', 5'-monophosphate.

Directory of Open Access Journals (Sweden)

Konstantinos Lefkimmiatis

Full Text Available BACKGROUND: While intracellular buffers are widely used to study calcium signaling, no such tool exists for the other major second messenger, cyclic AMP (cAMP. METHODS/PRINCIPAL FINDINGS: Here we describe a genetically encoded buffer for cAMP based on the high-affinity cAMP-binding carboxy-terminus of the regulatory subunit RIbeta of protein kinase A (PKA. Addition of targeting sequences permitted localization of this fragment to the extra-nuclear compartment, while tagging with mCherry allowed quantification of its expression at the single cell level. This construct (named "cAMP sponge" was shown to selectively bind cAMP in vitro. Its expression significantly suppressed agonist-induced cAMP signals and the downstream activation of PKA within the cytosol as measured by FRET-based sensors in single living cells. Point mutations in the cAMP-binding domains of the construct rendered the chimera unable to bind cAMP in vitro or in situ. Cyclic AMP sponge was fruitfully applied to examine feedback regulation of gap junction-mediated transfer of cAMP in epithelial cell couplets. CONCLUSIONS: This newest member of the cAMP toolbox has the potential to reveal unique biological functions of cAMP, including insight into the functional significance of compartmentalized signaling events.

Microbial activity in bentonite buffers. Literature study

Energy Technology Data Exchange (ETDEWEB)

Ratto, M.; Itavaara, M.

2012-07-01

The proposed disposal concept for high-level radioactive wastes involves storing the wastes underground in copper-iron containers embedded in buffer material of compacted bentonite. Hydrogen sulphide production by sulphate-reducing prokaryotes is a potential mechanism that could cause corrosion of waste containers in repository conditions. The prevailing conditions in compacted bentonite buffer will be harsh. The swelling pressure is 7-8 MPa, the amount of free water is low and the average pore and pore throat diameters are small. This literature study aims to assess the potential of microbial activity in bentonite buffers. Literature on the environmental limits of microbial life in extreme conditions and the occurrence of sulphatereducing prokaryotes in extreme environments is reviewed briefly and the results of published studies characterizing microbes and microbial processes in repository conditions or in relevant subsurface environments are presented. The presence of bacteria, including SRBs, has been confirmed in deep groundwater and bentonite-based materials. Sulphate reducers have been detected in various high-pressure environments, and sulphate-reduction based on hydrogen as an energy source is considered a major microbial process in deep subsurface environments. In bentonite, microbial activity is strongly suppressed, mainly due to the low amount of free water and small pores, which limit the transport of microbes and nutrients. Spore-forming bacteria have been shown to survive in compacted bentonite as dormant spores, and they are able to resume a metabolically active state after decompaction. Thus, microbial sulphide production may increase in repository conditions if the dry density of the bentonite buffer is locally reduced. (orig.)

Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture*

Science.gov (United States)

Mauceri, Daniela; Hagenston, Anna M.; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar

2015-01-01

Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. PMID:26231212

Description of buffer tests in 2005 - 2007. Results of laboratory tests

International Nuclear Information System (INIS)

Sanden, Torbjoern; Boergesson, Lennart; Dueck, Ann; Goudarzi, Reza; Loennqvist, Margareta; Nilsson, Ulf; Aakesson, Mattias

2008-12-01

distance block and the rock surface as a means of improving performance of the buffer, but for different reasons. In DAWE, the entire tunnel will be filled when a functional plug has been built in order to minimize internal erosion. In BD, the slot between the distance blocks and the rock surface may be filled with water after the installation of each section in order to improve the sealing ability of the distance blocks. The hydro-mechanical interaction between the buffer, the water filled slot and the rock are important factors in the functioning of the two design alternatives. 4. Piping through distance blocks. In BD, the distance block section is required to hydraulically seal and isolate all container sections. Since the distance blocks cannot be installed without a gap between the blocks and the rock surface this gap must be sealed by the swelling bentonite before piping can be prevented. This requirement is very difficult to achieve at high water inflow rate, and a large number of tests have been performed in order to determine the limits of the allowable gap between the bentonite and rock and to improve the design. 5. Hydraulic pressure on distance block end surface. Since the distance block section in BD must hydraulically seal all container sections, there will be very high water pressure inside the supercontainer section when the air-filled volumes have been filled with water. If the water pressure propagates deeply into the joint between distance blocks or between a distance block and the supercontainer lid, unacceptably high forces will be applied on the distance blocks and on the fixing ring outside the distance block section

Description of buffer tests in 2005 - 2007. Results of laboratory tests

Energy Technology Data Exchange (ETDEWEB)

Sanden, Torbjoern; Boergesson, Lennart; Dueck, Ann; Goudarzi, Reza; Loennqvist, Margareta; Nilsson, Ulf; Aakesson, Mattias (Clay Technology AB, Lund (Sweden))

2008-12-15

distance block and the rock surface as a means of improving performance of the buffer, but for different reasons. In DAWE, the entire tunnel will be filled when a functional plug has been built in order to minimize internal erosion. In BD, the slot between the distance blocks and the rock surface may be filled with water after the installation of each section in order to improve the sealing ability of the distance blocks. The hydro-mechanical interaction between the buffer, the water filled slot and the rock are important factors in the functioning of the two design alternatives. 4. Piping through distance blocks. In BD, the distance block section is required to hydraulically seal and isolate all container sections. Since the distance blocks cannot be installed without a gap between the blocks and the rock surface this gap must be sealed by the swelling bentonite before piping can be prevented. This requirement is very difficult to achieve at high water inflow rate, and a large number of tests have been performed in order to determine the limits of the allowable gap between the bentonite and rock and to improve the design. 5. Hydraulic pressure on distance block end surface. Since the distance block section in BD must hydraulically seal all container sections, there will be very high water pressure inside the supercontainer section when the air-filled volumes have been filled with water. If the water pressure propagates deeply into the joint between distance blocks or between a distance block and the supercontainer lid, unacceptably high forces will be applied on the distance blocks and on the fixing ring outside the distance block section

Breeding Bird Community Continues to Colonize Riparian Buffers Ten Years after Harvest.

Directory of Open Access Journals (Sweden)

Scott F Pearson

Full Text Available Riparian ecosystems integrate aquatic and terrestrial communities and often contain unique assemblages of flora and fauna. Retention of forested buffers along riparian habitats is a commonly employed practice to reduce potential negative effects of land use on aquatic systems. However, very few studies have examined long-term population and community responses to buffers, leading to considerable uncertainty about effectiveness of this practice for achieving conservation and management outcomes. We examined short- (1-2 years and long-term (~10 years avian community responses (occupancy and abundance to riparian buffer prescriptions to clearcut logging silvicultural practices in the Pacific Northwest USA. We used a Before-After-Control-Impact experimental approach and temporally replicated point counts analyzed within a Bayesian framework. Our experimental design consisted of forested control sites with no harvest, sites with relatively narrow (~13 m forested buffers on each side of the stream, and sites with wider (~30 m and more variable width unharvested buffer. Buffer treatments exhibited a 31-44% increase in mean species richness in the post-harvest years, a pattern most evident 10 years post-harvest. Post-harvest, species turnover was much higher on both treatments (63-74% relative to the controls (29%. We did not find evidence of local extinction for any species but found strong evidence (no overlap in 95% credible intervals for an increase in site occupancy on both Narrow (short-term: 7%; long-term 29% and Wide buffers (short-term: 21%; long-term 93% relative to controls after harvest. We did not find a treatment effect on total avian abundance. When assessing relationships between buffer width and site level abundance of four riparian specialists, we did not find strong evidence of reduced abundance in Narrow or Wide buffers. Silviculture regulations in this region dictate average buffer widths on small and large permanent streams that

Atmospheric spatial atomic layer deposition of Zn(O,S) buffer layer for Cu(In,Ga)Se2 solar cells

NARCIS (Netherlands)

Frijters, C.H.; Poodt, P.; Illeberi, A.

2016-01-01

Zinc oxysulfide has been grown by spatial atomic layer deposition (S-ALD) and successfully applied as buffer layer in Cu(In, Ga)Se2 (CIGS) solar cells. S-ALD combines high deposition rates (up to nm/s) with the advantages of conventional ALD, i.e. excellent control of film composition and superior

Buffer of Events as a Markovian Process

International Nuclear Information System (INIS)

Berdugo, J.; Casaus, J.; Mana, C.

2001-01-01

In Particle and Asro-Particle Physics experiments, the events which get trough the detectors are read and processes on-line before they are stored for a more detailed processing and future Physics analysis. Since the events are read and, usually, processed sequentially, the time involved in these operations can lead to a significant lose of events which is, to some extent, reduced by using buffers. We present an estimate of the optimum buffer size and the fraction of events lost for a simple experimental condition which serves as an introductory example to the use of Markow Chains.(Author)

Buffer of Events as a Markovian Process

Energy Technology Data Exchange (ETDEWEB)

Berdugo, J.; Casaus, J.; Mana, C.

2001-07-01

In Particle and Asro-Particle Physics experiments, the events which get trough the detectors are read and processes on-line before they are stored for a more detailed processing and future Physics analysis. Since the events are read and, usually, processed sequentially, the time involved in these operations can lead to a significant lose of events which is, to some extent, reduced by using buffers. We present an estimate of the optimum buffer size and the fraction of events lost for a simple experimental condition which serves as an introductory example to the use of Markow Chains.(Author)

Finite Element Simulation of Total Nitrogen Transport in Riparian Buffer in an Agricultural Watershed

Directory of Open Access Journals (Sweden)

Xiaosheng Lin

2016-03-01

Full Text Available Riparian buffers can influence water quality in downstream lakes or rivers by buffering non-point source pollution in upstream agricultural fields. With increasing nitrogen (N pollution in small agricultural watersheds, a major function of riparian buffers is to retain N in the soil. A series of field experiments were conducted to monitor pollutant transport in riparian buffers of small watersheds, while numerical model-based analysis is scarce. In this study, we set up a field experiment to monitor the retention rates of total N in different widths of buffer strips and used a finite element model (HYDRUS 2D/3D to simulate the total N transport in the riparian buffer of an agricultural non-point source polluted area in the Liaohe River basin. The field experiment retention rates for total N were 19.4%, 26.6%, 29.5%, and 42.9% in 1,3,4, and 6m-wide buffer strips, respectively. Throughout the simulation period, the concentration of total N of the 1mwide buffer strip reached a maximum of 1.27 mg/cm3 at 30 min, decreasing before leveling off. The concentration of total N about the 3mwide buffer strip consistently increased, with a maximum of 1.05 mg/cm3 observed at 60 min. Under rainfall infiltration, the buffer strips of different widths showed a retention effect on total N transport, and the optimum effect was simulated in the 6mwide buffer strip. A comparison between measured and simulated data revealed that finite element simulation could simulate N transport in the soil of riparian buffer strips.

A study of the kinematic characteristic of a coupling device between the buffer system and the flexible pipe of a deep-seabed mining system

Directory of Open Access Journals (Sweden)

Oh Jae-Won

2014-09-01

Full Text Available This paper concerns the kinematic characteristics of a coupling device in a deep-seabed mining system. This coupling device connects the buffer system and the flexible pipe. The motion of the buffer system, flexible pipe and mining robot are affected by the coupling device. So the coupling device should be considered as a major factor when this device is designed. Therefore, we find a stable kinematic device, and apply it to the design coupling device through this study. The kinematic characteristics of the coupling device are analyzed by multi-body dynamics simulation method, and finite element method. The dynamic analysis model was built in the commercial software DAFUL. The Fluid Structure Interaction (FSI method is applied to build the deep-seabed environment. Hydrodynamic force and moment are applied in the dynamic model for the FSI method. The loads and deformation of flexible pipe are estimated for analysis results of the kinematic characteristics

A study of the kinematic characteristic of a coupling device between the buffer system and the flexible pipe of a deep-seabed mining system

Directory of Open Access Journals (Sweden)

Jae-Won Oh

2014-09-01

Full Text Available This paper concerns the kinematic characteristics of a coupling device in a deep-seabed mining system. This coupling device connects the buffer system and the flexible pipe. The motion of the buffer system, flexible pipe and mining robot are affected by the coupling device. So the coupling device should be considered as a major factor when this device is designed. Therefore, we find a stable kinematic device, and apply it to the design coupling device through this study. The kinematic characteristics of the coupling device are analyzed by multi-body dynamics simulation method, and finite element method. The dynamic analysis model was built in the commercial software DAFUL. The Fluid Structure Interaction (FSI method is applied to build the deep-seabed environment. Hydrodynamic force and moment are applied in the dynamic model for the FSI method. The loads and deformation of flexible pipe are estimated for analysis results of the kinematic characteristics.

IMPACT OF BUFFER SIZE ON PQRS AND D-PQRS SCHEDULING ALGORITHMS

OpenAIRE

N. Narayanan Prasanth; Kannan Balasubramanian; R. Chithra Devi

2016-01-01

Most of the internet applications required high speed internet connectivity. Crosspoint Buffered Switches are widely used switching architectures and designing a scheduling algorithm is a major challenge. PQRS and D-PQRS are the two most successful schedulers used in Crosspoint Buffered Switches under unicast traffic. In this paper, we analysed the performance of PQRS and DPQRS algorithms by varying the crosspoint buffer size. Simulation result shows the delay performance of the switch increa...

The Finnish EMU Buffers and the Labour Market under Asymmetric Shocks

OpenAIRE

Alho, Kari

2004-01-01

The Finnish EMU buffers consist of elements built into the unemployment insurance and employment pension systems, which aim to stabilise employer contributions and employment during economic fluctuations in the EMU age. The paper simulates the role of these buffers in a hypothetical recession caused by an adverse asymmetric shock. The results show that the buffers play only a modest role in stabilising employment, although their importance increases as the shocks to the economy become greater...

Full scale tests of moisture buffer capacity of wall materials

DEFF Research Database (Denmark)

Mortensen, Lone Hedegaard; Rode, Carsten; Peuhkuri, Ruut Hannele

2005-01-01

that are harmful such as growth of house dust mites, surface condensation and mould growth. Therefore a series of experiments has been carried out in a full scale test facility to determine the moisture buffer effect of interior walls of cellular concrete and plaster board constructions. For the cellular concrete......Moisture buffer capacity of hygroscopic materials can be used to moderate peaks in the relative humidity (RH) of indoor air as well as moisture content variations in building materials and furnishing. This can help to ensure healthier indoor environments by preventing many processes...... of the changes of moisture content in specimens of the wall composites exposed to the same environment. It was found that the finishes had a big impact on the buffer performance of the underlying materials. Even though the untreated cellular concrete had a very high buffer capacity, the effect was strongly...

Comparative studies of social buffering: A consideration of approaches, terminology, and pitfalls.

Science.gov (United States)

Kiyokawa, Yasushi; Hennessy, Michael B

2018-03-01

KIYOKAWA, Y. and HENNESSY, M.B. Comparative studies of social buffering: A consideration of approaches, terminology, and pitfalls…NEUROSCI BIOBEHAV REV XXX-XXX, .- Over the past decades, there has been an increasing number of investigations of the impact of social variables on neural, endocrine, and immune outcomes. Among these are studies of "social buffering"-or the phenomenon by which affiliative social partners mitigate the response to stressors. Yet, as social buffering studies have become more commonplace, the variety of approaches taken, definitions employed, and divergent results obtained in different species can lead to confusion and miscommunication. The aim of the present paper, therefore, is to address terminology and approaches and to highlight potential pitfalls to the study of social buffering across nonhuman species. We review and categorize variables currently being employed in social buffering studies and provide an overview of responses measured, mediating sensory modalities and underlying mechanisms. It is our hope that the paper will be useful to those contemplating examination of social buffering in the context of their own research. Copyright © 2017 Elsevier Ltd. All rights reserved.

Selective Excitation of Window and Buffer Layers in Chalcopyrite Devices and Modules

Energy Technology Data Exchange (ETDEWEB)

Glynn, Stephen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Repins, Ingrid L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Burst, James M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beall, Carolyn L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bowers, Karen A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mansfield, Lorelle M [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-02-02

Window and buffer layers in chalcopyrite devices are well known to affect junctions, conduction, and photo-absorption properties of the device. Some of these layers, particularly 'buffers,' which are deposited directly on top of the absorber, exhibit metastable effects upon exposure to light. Thus, to understand device performance and/or metastability, it is sometimes desirable to selectively excite different layers in the device stack. Absorption characteristics of various window and buffer layers used in chalcopyrite devices are measured. These characteristics are compared with emission spectra of common and available light sources that might be used to optically excite such layers. Effects of the window and buffer absorption on device quantum efficiency and metastability are discussed. For the case of bath-deposited Zn(O,S) buffers, we conclude that this layer is not optically excited in research devices or modules. This provides a complimentary mechanism to the chemical differences that may cause long time constants (compared to devices with CdS buffers) associated with reaching a stable 'light-soaked' state.

Baroreflex buffering in sedentary and endurance exercise-trained healthy men.

Science.gov (United States)

Christou, Demetra D; Jones, Pamela Parker; Seals, Douglas R

2003-06-01

Baroreflex buffering plays an important role in arterial blood pressure control. Previous reports suggest that baroreflex sensitivity may be altered in endurance exercise-trained compared with untrained subjects. It is unknown, however, if in vivo baroreflex buffering is altered in the endurance exercise-trained state in humans. Baroreflex buffering was determined in 36 healthy normotensive men (18 endurance exercise-trained, 41+/-5 [SEM] years; 18 untrained, 41+/-4 years) by measuring the potentiation of the systolic blood pressure responses to a phenylephrine bolus and to incremental phenylephrine infusion during compared with before ganglionic blockade with trimethaphan. The exercise-trained men had a lower resting heart rate and higher maximal oxygen consumption and heart rate variability than the sedentary control subjects (all P=0.01). Mean levels and variability of blood pressure, cardiovagal baroreflex sensitivity (change in heart rate/change in systolic blood pressure), and basal muscle sympathetic nerve activity were not different in the two groups. The systolic blood pressure responses to phenylephrine were not different in the endurance-trained and untrained men before or during ganglionic blockade (P>0.6). Measures of baroreflex buffering with the use of a phenylephrine bolus (3.9+/-0.8 versus 4.0+/-0.7, trained versus untrained, P=0.85) and incremental infusion (2.8+/-0.4 versus 2.5+/-0.6, P=0.67) were similar in the two groups. Baroreflex buffering does not differ in endurance exercise-trained compared with untrained healthy men. These results support the concept that habitual vigorous endurance exercise does not modulate in vivo baroreflex buffering in healthy humans.

MATHEMATICAL MODELLING OF QUAZISTEADY MODE OF BEARING AIR BUFFER FILLING

Directory of Open Access Journals (Sweden)

E. D. Chertov

2014-01-01

Full Text Available Summary. Today the only way to eliminate contact with the product during the manufacturing process is to provide a support surface under its support surface air buffer layer formed due to the expiration of the working environment through holes perforated gas distribution grids forms. There proposed the method of contactless formation of products consisting of composite materials by the means of air buffer in the article. The results of theoretical and experimental investigations of hydro-gas-dynamic processes occurring when casting of organic- mineral composite material onto the bearing air buffer expressed in the form of mathematical description realizing original hypotheses reflected in the choice of transformation algorithm and limiting conditions are presented. On the base of obtained mathematical model the algorithm of calculation of optimum parameters of transporting systems with discretely powered gas buffer is developed. The method of deduction of a semi-finished product on the gas buffer, which allows to level the pressure field under the bearing surface of the deduction object due to the usage of devices of pseudo fluidized granular material in pneumatic chambers is offered. The application of this method allows to eliminate the possibility of contact between the composite material and the working surface of the equipment and also to reduce the cost of production of pneumatic devices, to improve operational characteristics of this equipment. Submitted depending allowed to develop the methodology and implementation of engineering calculation device for non-contact casting composite materials on air buffer, semi-industrial and industrial variants were created and put into production.

Beyond buffer zone protection: a comparative study of park and buffer zone products' importance to villagers living inside Royal Chitwan National Park and to villagers living in its buffer zone.

Science.gov (United States)

Straede, Steffen; Treue, Thorsten

2006-02-01

Even after 30 years of strict de jure protection, today's de facto extraction of products from Nepal's Royal Chitwan National Park (RCNP) and their great economic importance to local households suggests that this reality should be explicitly internalised in managing this world heritage park. Several studies have quantified local people's use of protected areas and estimated the value of such areas to them. However, few studies incorporate economic analyses to investigate the effect of management interventions on local communities' resource use and collection behaviour. In Nepal, buffer zones and especially buffer zone community forestry are seen as means to define and demarcate places, where local people may legally extract goods that are either identical to or relevant substitutes for products that are collected in protected areas. The intention is to resolve park-people conflicts over resource use. This article presents the findings of an in-depth study of the importance of natural resources to the livelihoods of 18 households. One village was located inside RCNP with no realistic alternatives to Park resources, while the other is located in the buffer zone with equal distance to the Park, a national forest and their community forest. For each household, the collection of products, allocation of time, and purchase and sale of goods were recorded daily through 12 consecutive months and economic values were calculated on the basis of local market prices and recorded quantities. The study shows that products from RCNP are of great importance to the livelihoods of local people. Furthermore, we find that products collected in the national forest substitute products from the Park, while the substitution effect of the community forest is small. Accordingly, the study illustrates that, irrespective of buffer zone community forestry, there is still a gap between local people's need for supplementing natural resources and their rights to satisfy them on a legal basis

Final report of the Buffer Mass Test - Volume 3: Chemical and physical stability of the buffer materials

International Nuclear Information System (INIS)

Pusch, R.

1985-11-01

The Buffer Mass Test offered a possibility to investigate whether chemical changes took place in the smectite component at heating to 125 degrees C for about one year. The alterations that could possibly take place were a slight charge change in the crystal lattice with an associated precipitation of silica compounds, and a tendency of illite formation. The analysis showed that there were indications of both but to such a slight extent that the processes could not have affected the physical properties, which was also demonstrated by determining the swelling pressure and the hydraulic conductivity. The BMT also showed that the erodibility of bentonite-based buffer materials is less than or about equal to what can be expected on theoretical grounds. (author)

Photo-induced wettability of TiO{sub 2} film with Au buffer layer

Energy Technology Data Exchange (ETDEWEB)

Purkayastha, Debarun Dhar; Sangani, L. D. Varma; Krishna, M. Ghanashyam [School of Physics, University of Hyderabad, Hyderabad-500046 (India); Madhurima, V., E-mail: madhurima.v@gmail.com [Department of Physics, Central University of Tamil Nadu, Thiruvarur-610004 (India)

2014-04-24

The effect of thickness of Au buffer layer (15-25 nm) between TiO{sub 2} film and substrate on the wettability of TiO{sub 2} films is reported. TiO{sub 2} films grown on Au buffer layer have a higher contact angle of 96-;100° as compared to 47.6o for the film grown without buffer layer. The transition from hydrophobicity to hydrophilicity under UV irradiation occurs within 10 min. for the buffer layered films whereas it is almost 30 min. for the film grown without buffer layer. The enhanced photo induced hydrophilicity is shown to be surface energy driven.

Reduction of buffering requirements: Another advantage of cooperative transmission

KAUST Repository

Bader, Ahmed

2015-04-01

Yet another advent of cooperative transmission is exposed in this letter. It is shown that cooperation lends itself to the reduction of buffer sizes of wireless sensor nodes. It is less likely to find the channel busy when cooperative transmission is employed in the network. Otherwise, in the lack of cooperation, the probability of build up of packet queues in transmission buffers increases.

2D and 3D finite element analysis of buffer-backfill interaction

International Nuclear Information System (INIS)

Leoni, M.

2013-08-01

Methods for backfilling and sealing of disposal tunnels in an underground repository for spent nuclear fuel are studied in cooperation between Finland (Posiva Oy) and Sweden (Svensk Kaernbraenslehantering AB, SKB) in 'BAckfilling and CLOsure of the deep repository' (Baclo) programme. Baclo phase III included modelling task force SP1: Finite element modelling of deformation of the backfill due to swelling of the buffer. The objective of the finite element modelling of the backfill was to study the interaction between the buffer and backfilling. The calculations aimed to find out how large deformations can happen in the buffer-backfill interface causing loosening of the buffer bentonite above the canister. The criterion used was that the saturated density of the buffer right above the canister should be higher than 1990 kg/m 3 . This report presents the results of finite element numerical analyses carried out by Wesi Geotecnica Srl. The modelling calculations were conducted with the so-called OL1-2 deposition tunnel geometry (Juvankoski 2009). Several parameters have been considered, varying from geometry variations to different mechanical constitutive models for different components of the model. In all analyses it has been assumed that the buffer material is fully saturated, thus exerting the isotropic swelling pressure estimated in the range 7 MPa .. 15 MPa, against a fully-dry backfill, which is no doubt the 'worst case scenario' with the highest risk to lead in decrease in dry density of the buffer. Friedland clay has been considered for backfill blocks and 30/70 mixture for foundation bed on which backfill blocks are installed. Preliminarily, finite element analyses have been performed with newly released PLAXIS 2D 2010 within the assumption of axial symmetry, the purpose of this first set of calculations being the evaluation of most relevant parameters influencing the deformations of buffer material. Hence, full 3D calculations have been performed with PLAXIS

Ligand-enhanced electrokinetic remediation of metal-contaminated marine sediments with high acid buffering capacity.

Science.gov (United States)

Masi, Matteo; Iannelli, Renato; Losito, Gabriella

2016-06-01

The suitability of electrokinetic remediation for removing heavy metals from dredged marine sediments with high acid buffering capacity was investigated. Laboratory-scale electrokinetic remediation experiments were carried out by applying two different voltage gradients to the sediment (0.5 and 0.8 V/cm) while circulating water or two different chelating agents at the electrode compartments. Tap water, 0.1 M citric acid and 0.1 M ethylenediaminetetraacetic acid (EDTA) solutions were used respectively. The investigated metals were Zn, Pb, V, Ni and Cu. In the unenhanced experiment, the acid front could not propagate due to the high acid buffering capacity of the sediments; the production of OH(-) ions at the cathode resulted in a high-pH environment causing the precipitation of CaCO3 and metal hydroxides. The use of citric acid prevented the formation of precipitates, but solubilisation and mobilisation of metal species were not sufficiently achieved. Metal removal was relevant when EDTA was used as the conditioning agent, and the electric potential was raised up to 0.8 V/cm. EDTA led to the formation of negatively charged complexes with metals which migrated towards the anode compartment by electromigration. This result shows that metal removal from sediments with high acid buffering capacity may be achieved by enhancing the electrokinetic process by EDTA addition when the acidification of the medium is not economically and/or environmentally sustainable.

Simulation study on single event burnout in linear doping buffer layer engineered power VDMOSFET

Science.gov (United States)

Yunpeng, Jia; Hongyuan, Su; Rui, Jin; Dongqing, Hu; Yu, Wu

2016-02-01

The addition of a buffer layer can improve the device's secondary breakdown voltage, thus, improving the single event burnout (SEB) threshold voltage. In this paper, an N type linear doping buffer layer is proposed. According to quasi-stationary avalanche simulation and heavy ion beam simulation, the results show that an optimized linear doping buffer layer is critical. As SEB is induced by heavy ions impacting, the electric field of an optimized linear doping buffer device is much lower than that with an optimized constant doping buffer layer at a given buffer layer thickness and the same biasing voltages. Secondary breakdown voltage and the parasitic bipolar turn-on current are much higher than those with the optimized constant doping buffer layer. So the linear buffer layer is more advantageous to improving the device's SEB performance. Project supported by the National Natural Science Foundation of China (No. 61176071), the Doctoral Fund of Ministry of Education of China (No. 20111103120016), and the Science and Technology Program of State Grid Corporation of China (No. SGRI-WD-71-13-006).

Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

International Nuclear Information System (INIS)

Ardón, Marcelo; Duff, John H.; Ramírez, Alonso; Small, Gaston E.; Jackman, Alan P.; Triska, Frank J.; Pringle, Catherine M.

2013-01-01

Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (∼ 6) than streams that do not receive IGF (pH ∼ 5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO 3 − ) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO 3 − was an important buffering mechanism in both streams. Base cation, Fe 2+ , and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and suggest that low

Optimization approaches to mpi and area merging-based parallel buffer algorithm

Directory of Open Access Journals (Sweden)

Junfu Fan

Full Text Available On buffer zone construction, the rasterization-based dilation method inevitably introduces errors, and the double-sided parallel line method involves a series of complex operations. In this paper, we proposed a parallel buffer algorithm based on area merging and MPI (Message Passing Interface to improve the performances of buffer analyses on processing large datasets. Experimental results reveal that there are three major performance bottlenecks which significantly impact the serial and parallel buffer construction efficiencies, including the area merging strategy, the task load balance method and the MPI inter-process results merging strategy. Corresponding optimization approaches involving tree-like area merging strategy, the vertex number oriented parallel task partition method and the inter-process results merging strategy were suggested to overcome these bottlenecks. Experiments were carried out to examine the performance efficiency of the optimized parallel algorithm. The estimation results suggested that the optimization approaches could provide high performance and processing ability for buffer construction in a cluster parallel environment. Our method could provide insights into the parallelization of spatial analysis algorithm.

Riparian ecosystems and buffers - multiscale structure, function, and management: introduction

Science.gov (United States)

Kathleen A. Dwire; Richard R. Lowrance

2006-01-01

Given the importance of issues related to improved understanding and management of riparian ecosystems and buffers, the American Water Resources Association (AWRA) sponsored a Summer Specialty Conference in June 2004 at Olympic Valley, California, entitled 'Riparian Ecosystems and Buffers: Multiscale Structure, Function, and Management.' The primary objective...

Exchangeability of bentonite buffer and backfill materials

Energy Technology Data Exchange (ETDEWEB)

Savage, D. [Savage Earth Associates Ltd, Bournemouth (United Kingdom); Arthur, R. [Intera Inc, Ottawa, ON, (Canada); Luukkonen, A.

2012-08-15

Clay-based buffer and tunnel backfill materials are important barriers in the KBS-3 repository concept for final disposal of spent nuclear fuel in Finland. One issue that is relevant to material properties is the degree to which different bentonite compositions can be regarded as interchangeable. In Posiva's current repository design, the reference bentonite composition is MX-80, a sodium montmorillonite dominated clay. Posiva would like to be able to use bentonite with Ca-montmorillonite as the dominant clay mineral. However, at this stage, it is not clear what supporting data need to be acquired/defined to be able to place the state of knowledge of Ca-bentonite at the same level as that of Na-bentonite. In this report, the concept of bentonite exchangeability has been evaluated through consideration of how bentonite behaviour may be affected in six key performance-relevant properties, namely (1) mineralogical composition and availability of materials, (2) hydraulic conductivity, (3) mechanical and rheological properties, (4) long-term alteration, (5) colloidal properties, and (6) swelling pressure. The report evaluates implications for both buffer and backfill. Summary conclusions are drawn from these sections to suggest how bentonite exchangeability may be addressed in regulatory assessments of engineered barrier design for a future geological repository for spent fuel in Finland. Some important conclusions are: (a) There are some fundamental differences between Ca- and Na-bentonites such as colloidal behaviour, pore structure and long-term alteration that could affect the exchangeability of these materials as buffer or backfill materials and which should be further evaluated; (b) Additional experimental data are desirable for some issues such as long-term alteration, hydraulic properties and swelling behaviour, (c) The minor mineral content of bentonites is very variable, both between different bentonites and within the same bentonite type, it is not clear

Buffer standards for the physiological pH of the zwitterionic compound of 3-(N-morpholino)propanesulfonic acid (MOPS) from T = (278.15 to 328.15) K

International Nuclear Information System (INIS)

Roy, Lakshmi N.; Roy, Rabindra N.; Allen, Kathleen A.; Mehrhoff, Casey J.; Henson, Isaac B.; Stegner, Jessica M.

2012-01-01

Highlights: ► This work reports pH values of MOPS buffer. ► Liquid junction potential correction is applied. ► These values will be used by clinical and biomedical scientists. ► The pH values lie within 6.8 to 7.5. - Abstract: This paper reports the pH values of five NaCl-free buffer solutions and 11 buffer compositions containing NaCl at I = 0.16 mol · kg −1 . Conventional pa H values are reported for 16 buffer solutions with and without NaCl salt. The operational pH values have been calculated for five buffer solutions and are recommended as pH standards at T = (298.15 and 310.15) K after correcting the liquid junction potentials. For buffer solutions with the composition m 1 = 0.04 mol · kg −1 , m 2 = 0.08 mol · kg −1 , m 3 = 0.08 mol · kg −1 at I = 0.16 mol · kg −1 , the pH at 310.15 K is 7.269, which is close to 7.407, the pH of blood serum. It is recommended as a pH standard for biological specimens.

Unusual buffer action of free-standing nanoscopically confined water.

Science.gov (United States)

Liao, Kylin; Xu, Xiaozhou; Du, Xuezhong

2010-01-15

The acid-base properties of nanoscopic water confined in the black soap films (BSFs), which were prepared from aqueous solutions of sodium dodecylsulphate (SDS) with the dye neutral red (NR) as a pH probe, were investigated using a combination of UV-vis and FTIR spectroscopy. For the SDS micellar solutions at pH 1.0-9.5 adjusted with HCl/NaOH solutions and at pH 9.4 with ammonium buffered solution, the aqueous core thicknesses in the corresponding BSFs ranged from 2.7 to 6.2 nm, and the nanoscopically confined water exhibits unusual buffer action resistant not only to acidic/alkaline solutions but also to standard buffer solution. In the heavily water-depleted confined zones, it is most likely that charge pairs in proton-transfer reactions could not be formed effectively and proton transfer was prohibited in the absence of sufficient solvating ability. Theoretical analyzes indicated that the buffer action of the nanoscopic water originated from the confinement effect of two charged surfaces of the BSFs. These results might inspire deeper understanding and further studies of biobuffering, enzyme superactivity, acid-catalyzed reactions, and Nafion fuel cell membranes.

Swelling of the buffer of KBS-3V deposition hole

International Nuclear Information System (INIS)

Lempinen, A.

2006-12-01

At the time of the installation of spent nuclear fuel canister in the KBS-3V deposition hole, empty space is left around bentonite buffer for technical reasons. The gap between the buffer and the canister is about 10 mm, and the gap between the buffer and the rock is 30 to 35 mm. In this study, the swelling of the buffer to fill the gaps was simulated, when the gaps are initially filled with water and no external water is available. The model used here is a thermodynamical model for swelling clay, with parameters determined for bentonite. The simulations presented here were performed with Freefem++ software, which is a finite element application for partial differential equations. These equations come from the material model. The simulation results show that the swelling fills the outer gaps in few years, but no significant swelling pressure is generated. For swelling pressure, external water supply is required. (orig.)

Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture.

Science.gov (United States)

Mauceri, Daniela; Hagenston, Anna M; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar

2015-09-18

Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Critical micelle concentration of surfactants in aqueous buffered and unbuffered systems

International Nuclear Information System (INIS)

Fuguet, Elisabet; Rafols, Clara; Roses, Marti; Bosch, Elisabeth

2005-01-01

Critical micelle concentration (CMC) of sodium dodecyl sulphate (SDS), lithium perfluorooctanesulfonate (LPFOS), hexadecyltrimethylammonium bromide (HTAB), tetradecyltrimethylammonium bromide (TTAB), and sodium cholate (SC), surfactants commonly used as pseudostationary phases in micellar electrokinetic chromatography (MEKC), have been determined by means of three different methods: MEKC, spectrophotometry, and conductometry. Determinations have been performed in water, and also in different concentrations of phosphate buffer at pH 7.0. CMC values ranging from 8.08 (water) to 1.99 (50 mM phosphate buffer) mM for SDS, from 7.16 (water) to 2,81 (30 mM phosphate buffer) mM for LPFOS, from 3.77 (water) to 1.93 (20 mM phosphate buffer) mM for TTAB, from 0.91 (water) to ∼0.34 (20 mM phosphate buffer) for HTAB, and around 13 mM (20 mM phosphate buffer) for SC, are obtained. The effect of the electrolyte concentration on the CMC, as well as the linear relationship between the electrolyte counter-ion concentration and the CMC are discussed. This linear relationship provides an easy way for users to estimate the CMC of a MEKC system, at a given electrolyte concentration. A comparison between experimental methods, as well as a discussion about the suitability of a given method for the determination of the CMC for a given surfactant system is also provided

An analysis of extrusion of buffer material into fracture behavior by diffusion model

International Nuclear Information System (INIS)

Matsumoto, Kazuhiro; Tanai, Kenji; Kanno, Takeshi; Iwata, Yumiko

2005-06-01

The buffer that will be used as a component of the engineered barriers system swells when saturated by groundwater. As a result of this swelling, buffer may penetrate into the surrounding rock zone through open fractures. It sustained for extremely long periods of time, the buffer extrusion could lead to reduction of buffer density, which may in turn degrade the assumed performance. In this report, the viscosity of bentonite was measured as one of the parameter of diffusion model. In addition, the simulation analysis was carried out to confirm the applicability of diffusion model. Moreover, an analytical evaluation on extrusion behavior of buffer into rock fractures was performed to estimate the long-term stability of buffer as reduction of density. (1) Measurement of the viscosity of bentonite. The viscosity of bentonite is measured by the Rheometer. The viscosity of bentonite indicated tendency to non-Newton flow. The viscosity of bentonite at water contents of 400-1000% was estimated. The evaluated value of the viscosity was modified based on this measurement. (2) Simulation analysis of an experiment results. The simulation analysis of the experimental result using diffusion model was performed to confirm applicability of this model. The results of the simulation reasonably agreed with obtained experimental result. (3) Example analysis of a long-term stability of buffer. The analysis of a long-term stability of buffer as reduction of density was performed to compare with the results in H12 report. In this analysis, the density of the buffer material decreased earlier than the results in H12 report. In addition, a long-term change in the density of the buffer material under seawater condition was preliminary calculated. As a result, it is indicated that extrusion behavior is not significant under seawater condition. (author)

Multibody dynamical modeling for spacecraft docking process with spring-damper buffering device: A new validation approach

Science.gov (United States)

Daneshjou, Kamran; Alibakhshi, Reza

2018-01-01

In the current manuscript, the process of spacecraft docking, as one of the main risky operations in an on-orbit servicing mission, is modeled based on unconstrained multibody dynamics. The spring-damper buffering device is utilized here in the docking probe-cone system for micro-satellites. Owing to the impact occurs inevitably during docking process and the motion characteristics of multibody systems are remarkably affected by this phenomenon, a continuous contact force model needs to be considered. Spring-damper buffering device, keeping the spacecraft stable in an orbit when impact occurs, connects a base (cylinder) inserted in the chaser satellite and the end of docking probe. Furthermore, by considering a revolute joint equipped with torsional shock absorber, between base and chaser satellite, the docking probe can experience both translational and rotational motions simultaneously. Although spacecraft docking process accompanied by the buffering mechanisms may be modeled by constrained multibody dynamics, this paper deals with a simple and efficient formulation to eliminate the surplus generalized coordinates and solve the impact docking problem based on unconstrained Lagrangian mechanics. By an example problem, first, model verification is accomplished by comparing the computed results with those recently reported in the literature. Second, according to a new alternative validation approach, which is based on constrained multibody problem, the accuracy of presented model can be also evaluated. This proposed verification approach can be applied to indirectly solve the constrained multibody problems by minimum required effort. The time history of impact force, the influence of system flexibility and physical interaction between shock absorber and penetration depth caused by impact are the issues followed in this paper. Third, the MATLAB/SIMULINK multibody dynamic analysis software will be applied to build impact docking model to validate computed results and

MOISTURE-BUFFERING CHARACTERISTICS OF BUILDING MATERIALS

Directory of Open Access Journals (Sweden)

Young Cheol Choi

2016-05-01

Full Text Available The humidity level of indoor air is an important factor influencing the air quality and energy consumption of buildings, as well as the durability of building components. Indoor humidity levels depend on several factors, such as moisture sources, air flow, and the adsorption/desorption properties of materials. The moisture-buffering characteristics of building materials that are in contact with indoor air may help moderate the variations of indoor humidity, especially in the summer and winter. In this study, the moisture adsorption/desorption properties of building materials were investigated experimentally and numerically. These properties can be used to characterize the ability of building materials to exchange moisture with the indoor environment. This study indicates that a building material surface resistivity was the main factor creating variations of moisture buffering.

Chemical buffering capacity of clay rock

International Nuclear Information System (INIS)

Beaucaire, C.; Pearson, F.J.; Gautschi, A.

2004-01-01

The long-term performance of a nuclear waste repository is strongly dependent on the chemical properties of the host rock. The host rock establishes the chemical environment that determines such important performance attributes as radionuclide solubilities from the waste and the transport rates from the repository to the accessible environment. Clay-rich rocks are especially favourable host rocks because they provide a strong buffering capacity to resist chemical changes prompted either internally, by reactions of the waste itself and emplacement materials, or externally, by changes in the hydrologic systems surrounding the host rock. This paper will focus on three aspects of the stability of clay-rich host rocks: their ability to provide pCO 2 and redox buffering, and to resist chemical changes imposed by changes in regional hydrology and hydro-chemistry. (authors)

The Influence of Phosphate Buffer on the Formation of N-Nitrosodimethylamine from Dimethylamine Nitrosation

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Long Xu

2013-01-01

Full Text Available Buffer solutions were widely used for almost all the investigations concerning N-nitrosodimethylamine (NDMA, a member of powerful mutagenic and carcinogenic compounds which are ubiquitous in the environment. However, whether or how the buffer matrixes influence NDMA formation is still unknown. The effect of buffer solutions on NDMA formation from the nitrosation of dimethylamine (DMA by nitrite (NaNO2 was investigated at pH 6.4 in four kinds of buffer solutions, that is, Na2HPO4/C6H8O7, Na3(C6H5O7/C6H8O7, NaH2PO4/NaOH, and NaH2PO4/Na2HPO4. Our observations demonstrate an unexpected inhibitory effect of the buffer solutions on NDMA formation and the phosphate buffer plays a more significant role in inhibiting NDMA formation compared to the citrate buffer. Moreover, the amount of the phosphate in the buffer was also found to greatly impact the formation of NDMA. A further investigation indicates that it is the interaction between NaH2PO4 and reactant NaNO2 rather than DMA that leads to the inhibitory effect of phosphate buffer during the DMA nitrosation reaction. This study expands the understanding of the influence of buffer solution on nitrosamines formation through the nitrosation pathway and further gives a hint for water plants to reduce the formation of nitrosamines.

Aluminum elution and precipitation in glass vials: effect of pH and buffer species.

Science.gov (United States)

Ogawa, Toru; Miyajima, Makoto; Wakiyama, Naoki; Terada, Katsuhide

2015-02-01

Inorganic extractables from glass vials may cause particle formation in the drug solution. In this study, the ability of eluting Al ion from borosilicate glass vials, and tendencies of precipitation containing Al were investigated using various pHs of phosphate, citrate, acetate and histidine buffer. Through heating, all of the buffers showed that Si and Al were eluted from glass vials in ratios almost the same as the composition of borosilicate glass, and the amounts of Al and Si from various buffer solutions at pH 7 were in the following order: citrate > phosphate > acetate > histidine. In addition, during storage after heating, the Al concentration at certain pHs of phosphate and acetate buffer solution decreased, suggesting the formation of particles containing Al. In citrate buffer, Al did not decrease in spite of the high elution amount. Considering that the solubility profile of aluminum oxide and the Al eluting profile of borosilicate glass were different, it is speculated that Al ion may be forced to leach into the buffer solution according to Si elution on the surface of glass vials. When Al ions were added to the buffer solutions, phosphate, acetate and histidine buffer showed a decrease of Al concentration during storage at a neutral range of pHs, indicating the formation of particles containing Al. In conclusion, it is suggested that phosphate buffer solution has higher possibility of forming particles containing Al than other buffer solutions.

Sampling phase lock loop (PLL) with low power clock buffer

NARCIS (Netherlands)

Gao, X.; Bahai, A.; Bohsali, M.; Djabbari, A.; Klumperink, Eric A.M.; Nauta, Bram; Socci, G.

2013-01-01

A sampling phase locked loop (PLL) circuit includes a pull-up/down buffer configured to convert an oscillator reference clock into a square wave sampling control signal input to a sampling phase detector. The buffer circuit is configured to reduce power by controlling the switching of the pull-up

Glucose buffer is suitable for blood group conversion with α-N acetylgalactosaminidase and α-galactosidase.

Science.gov (United States)

Gao, Hong-Wei; Li, Su-Bo; Bao, Guo-Qiang; Zhang, Xue; Li, Hui; Wang, Ying-Li; Tan, Ying-Xia; Ji, Shou-Ping; Gong, Feng

2014-01-01

It is well known that the buffer plays a key role in the enzymatic reaction involved in blood group conversion. In previous study, we showed that a glycine buffer is suitable for A to O or B to O blood group conversion. In this study, we investigated the use of 5% glucose and other buffers for A to O or B to O blood group conversion by α-N-acetylgalactosaminidase or α-galactosidase. We compared the binding ability of α-N-acetylgalactosaminidase/α-galactosidase with red blood cells (RBC) in different reaction buffers, such as normal saline, phosphate-buffered saline (PBS), a disodium hydrogen phosphate-based buffer (PCS), and 5% commercial glucose solution. The doses of enzymes necessary for the A/B to O conversion in different reaction buffers were determined and compared. The enzymes' ability to bind to RBC was evaluated by western blotting, and routine blood typing and fluorescence activated cell sorting was used to evaluate B/A to O conversion efficiency. The A to O conversion efficiency in glucose buffer was similar to that in glycine buffer with the same dose (>0.06 mg/mL pRBC). B to O conversion efficiency in glucose buffer was also similar to that in glycine buffer with the same dose (>0.005 mg/mL pRBC). Most enzymes could bind with RBC in glycine or glucose buffer, but few enzymes could bind with RBC in PBS, PCS, or normal saline. These results indicate that 5% glucose solution provides a suitable condition for enzymolysis, especially for enzymes combining with RBC. Meanwhile, the conversion efficiency of A/B to O was similar in glucose buffer and glycine buffer. Moreover, 5% glucose solution has been used for years in venous transfusion, it is safe for humans and its cost is lower. Our results do, therefore, suggest that 5% glucose solution could become a novel suitable buffer for A/B to O blood group conversion.

Agroforestry buffers for nonpoint source pollution reductions from agricultural watersheds.

Science.gov (United States)

Udawatta, Ranjith P; Garrett, Harold E; Kallenbach, Robert

2011-01-01

Despite increased attention and demand for the adoption of agroforestry practices throughout the world, rigorous long-term scientific studies confirming environmental benefits from the use of agroforestry practices are limited. The objective was to examine nonpoint-source pollution (NPSP) reduction as influenced by agroforestry buffers in watersheds under grazing and row crop management. The grazing study consists of six watersheds in the Central Mississippi Valley wooded slopes and the row crop study site consists of three watersheds in a paired watershed design in Central Claypan areas. Runoff water samples were analyzed for sediment, total nitrogen (TN), and total phosphorus (TP) for the 2004 to 2008 period. Results indicate that agroforestry and grass buffers on grazed and row crop management sites significantly reduce runoff, sediment, TN, and TP losses to streams. Buffers in association with grazing and row crop management reduced runoff by 49 and 19%, respectively, during the study period as compared with respective control treatments. Average sediment loss for grazing and row crop management systems was 13.8 and 17.9 kg ha yr, respectively. On average, grass and agroforestry buffers reduced sediment, TN, and TP losses by 32, 42, and 46% compared with the control treatments. Buffers were more effective in the grazing management practice than row crop management practice. These differences could in part be attributed to the differences in soils, management, and landscape features. Results from this study strongly indicate that agroforestry and grass buffers can be designed to improve water quality while minimizing the amount of land taken out of production. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Approach to Accelerating Dissolved Vector Buffer Generation in Distributed In-Memory Cluster Architecture

Directory of Open Access Journals (Sweden)

Jinxin Shen

2018-01-01

Full Text Available The buffer generation algorithm is a fundamental function in GIS, identifying areas of a given distance surrounding geographic features. Past research largely focused on buffer generation algorithms generated in a stand-alone environment. Moreover, dissolved buffer generation is data- and computing-intensive. In this scenario, the improvement in the stand-alone environment is limited when considering large-scale mass vector data. Nevertheless, recent parallel dissolved vector buffer algorithms suffer from scalability problems, leaving room for further optimization. At present, the prevailing in-memory cluster-computing framework—Spark—provides promising efficiency for computing-intensive analysis; however, it has seldom been researched for buffer analysis. On this basis, we propose a cluster-computing-oriented parallel dissolved vector buffer generating algorithm, called the HPBM, that contains a Hilbert-space-filling-curve-based data partition method, a data skew and cross-boundary objects processing strategy, and a depth-given tree-like merging method. Experiments are conducted in both stand-alone and cluster environments using real-world vector data that include points and roads. Compared with some existing parallel buffer algorithms, as well as various popular GIS software, the HPBM achieves a performance gain of more than 50%.

Structural and functional characteristics of buffer strip vegetation in an agricultural landscape - high potential for nutrient removal but low potential for plant biodiversity.

Science.gov (United States)

Hille, Sandra; Andersen, Dagmar Kappel; Kronvang, Brian; Baattrup-Pedersen, Annette

2018-07-01

Vegetated buffer strips constitute a transition zone between terrestrial and aquatic ecosystems and provide several ecosystem services. Buffer strips are often applied as a mitigation measure against diffuse pollution in agricultural areas, primarily because they may retain nutrients and in this way help protect the aquatic environment. Additionally, they can improve biodiversity in an otherwise homogenous landscape and may therefore have a value in their own right. In the present study, we characterized the structural and functional features of the vegetation in Danish buffer strips using a nationwide dataset to explore: i) their floristic quality in terms of species diversity and conservation value and ii) based on their functional characteristics, their potential to retain nutrients. Moreover, we analyzed how the structural and functional characteristics varied along gradients in the environmental features of the catchment. We found that the floristic quality of the buffer vegetation was generally low, exhibiting an average of only 3.3% of the number of species of conservation interest. Instead, Danish buffer strips were dominated by widespread and productive species that are tolerant of anthropogenic impacts in the catchment. The abundance of highly productive plant species was positively related to high intensity land use, whereas the abundance of stress-tolerant plant species was positively related to low intensity land use. The high productivity of the buffer strips implies a large bio-storage potential, and these areas might therefore offer an opportunity to remove nutrients by harvesting the plant biomass. We discuss how Danish buffer strips could be exploited via appropriate management (e.g. harvesting) to maximize nutrient retention and at the same time improve floristic quality. Copyright © 2018 Elsevier B.V. All rights reserved.

Database on gas migration tests through bentonite buffer material

International Nuclear Information System (INIS)

Tanai, Kenji

2009-02-01

Carbon steel is a candidate material for an overpack for geological disposal of high-level radioactive waste in Japan. The corrosion of the carbon steel overpack in aqueous solution under anoxic conditions will cause the generation of hydrogen gas, which may affect hydrological and mechanical properties of the bentonite buffer. To evaluate such an effect of gas generation, it is necessary to develop a model of gas migration through bentonite buffer material taking account of data obtained from experiments. The gas migration experiments under both unsaturated and saturated conditions have been carried out to clarify the fundamental characteristics of bentonite for gas migration. This report compiles the experimental data obtained from gas migration tests for buffer material which has been conducted by JAEA until December, 2007. A CD-ROM is attached as an appendix. (author)

Buffer development in KBS-3H repository design variant

International Nuclear Information System (INIS)

Sanden, T.; Boergesson, L.; Autio, J.; Oehberg, A.; Anttila, P.

2010-01-01

Document available in extended abstract form only. KBS-3H project is a joint project between Svensk Kaernbraenslehantering AB (SKB) in Sweden and Posiva Oy in Finland. The overall objectives of the project phase are to demonstrate that the horizontal deposition alternative is technically feasible and to demonstrate that it fulfils the same long-term safety requirements as the reference design KBS-3V, which calls for vertical emplacement of the canisters in individual deposition holes. KBS-3H and KBS-3V are the two variants of the KBS-3 method. In KBS-3H each spent fuel canister, with a surrounding layer of bentonite clay, is placed in a perforated steel cylinder prior to disposal; the entire assembly is called the supercontainer. Several super-containers are positioned along up to 300 m long approximately horizontal deposition drifts. The drifts will be excavated at the depth of about 420 m in bedrock. Bentonite distance blocks separate the super-containers, one from another, along the drift. The bentonite inside the super-containers and the bentonite distance blocks are jointly termed the buffer. There are two KBS-3H design alternatives; a design based on Drainage, Artificial Watering and air Evacuation (DAWE) and a less mature alternative called Semi Tight Compartments design (STC). Significant effort has been made in the KBS-3H project to solve the functional uncertainties related to buffer behaviour, which could e.g. cause piping, erosion, displacement and rupture of distance blocks. Some of the issues were prioritised as being important if there was clear uncertainty regarding the ability of the buffer to fulfil the specified requirements with respect to this issue. The design components in KBS-3H design alternatives include currently significant amounts of iron and titanium as possible alternative material to iron. Therefore the buffer development work has also included studies on the Fe-bentonite and Ti-bentonite interaction. The work has included testing in

Stacking by electroinjection with discontinuous buffers in capillary zone electrophoresis.

Science.gov (United States)

Shihabi, Zak K

2002-08-01

The work presented here demonstrates that electroinjection can be performed using discontinuous buffers, which can result in better stacking than that obtained by hydrodynamic injection. The sample can be concentrated at the tip of the capillary leaving practically the whole capillary for sample separation. This results in several advantages, such as better sample concentration, higher plate number and shorter time of stacking. However, sample introduction by electromigration is suited for samples free or low in salt content. Samples, which are high in salt content, are better introduced by the hydrodynamic injection for stacking by the discontinuous buffers. Different simple methods to introduce the discontinuity in the buffer for electroinjection are discussed.

Direct-reading spectrochemical analysis of magnesium alloys

International Nuclear Information System (INIS)

Roca Adell, M.

1964-01-01

A Quantometer has been applied to the determination of aluminum, berylium, calcium, iron, silicon and zinc in magnesium alloys Magnox, after the conversion of the samples to the oxide. For the aluminum, whose concentration is relatively high, the conducting briquets technique with an interrupted discharge is employed, using the magnesium as the internal standard. For the other elements a total burning method with direct current arc is employed, using also the magnesium as the internal standard. (Author) 7 refs

The Maintenance of Cross-Domain Associations in the Episodic Buffer

Science.gov (United States)

Langerock, Naomi; Vergauwe, Evie; Barrouillet, Pierre

2014-01-01

The episodic buffer has been described as a structure of working memory capable of maintaining multimodal information in an integrated format. Although the role of the episodic buffer in binding features into objects has received considerable attention, several of its characteristics have remained rather underexplored. This is the case for its…

Solvation consequences of polymer PVP with biological buffers MES, MOPS, and MOPSO in aqueous solutions

International Nuclear Information System (INIS)

Gupta, Bhupender S.; Chen, Bo-Ren; Lee, Ming-Jer

2015-01-01

Highlights: • Densities and viscosities data for aqueous solutions with PVP and/or buffer. • The studied buffers include MES, MOPS, and MOPSO. • DFT was used to estimate the binding energies of the (PVP + buffer) complexes. • The viscosity data were correlated with the Jones–Dole equation. • The investigated buffers behave as Kosmotropies. - Abstract: Densities and viscosities were measured for the aqueous buffer (MES, MOPS, or MOPSO) solutions containing different concentrations of polyvinylpyrrolidone (PVP) (5, 10, 15, 20 and 30) mass% at temperatures from (298.15 to 318.15) K under atmospheric pressure. The DFT calculations were also performed and the binding energies of the possible (PVP + buffer) complexes were obtained. The experimental and computational results reveal the interactions of the PVP with the constituent compounds in the aqueous buffer solutions. Additionally we have explored the solvation behavior of the buffers by measuring the densities and the viscosities data of the aqueous buffer solutions from (0.0 to 1.0) mol · kg"−"1 at temperatures from (298.15 to 318.15) K. The viscosity results were correlated with the Jones–Dole equation. The correlated results confirmed that all the investigated buffers behave as Kosmotropes (structure makers).

Improvement in reliability of the long-term mechanical behavior of buffer material

International Nuclear Information System (INIS)

Takaji, Kazuhiko; Shigeno, Yoshimasa; Shimogouchi, Takafumi; Hirai, Takashi; Shiratake, Toshikazu

2005-02-01

On the R and D of the HLW repository, it is essential that Engineered Barrier System (EBS) is stable mechanically over a long period of time for maintaining each ability required to EBS. After closing the repository, the various external forces will be affected to the buffer intricately for a long period of time. So, evaluation of mechanical behavior of the buffer is important to carry out safety assessment of EBS. In this report, the effects of mechanical behavior of the buffer to its safety performance are examined. As a result, the ability to filtrate colloids and the ability to keep diffusion-dominated environment are maintained for 100,000 years. Natural analogue of bentonite ore is also done to corroborate viscous parameter of the buffer. The results shows that the laboratory test data is reasonable compared with the analogized viscous parameters of the 15M years aged ore. Next, the mechanical parameters of the buffer under brine environment are examined. Then the mechanical behavior of the buffer is analyzed. Throughout these processes, the scheme for freshwater environment is confirmed to be valid under brine environment. At the last, the EBS field-test that is planned at Horonobe underground laboratory is analyzed. The analysis is encountered viscous behavior of the buffer and the surrounding rock under corrosion expansion of the overpack. The result offers the mechanical data to design the field test. (author)

Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

Energy Technology Data Exchange (ETDEWEB)

Ardón, Marcelo, E-mail: ardonsayaom@ecu.edu [Department of Biology and North Carolina Center for Biodiversity, East Carolina University, Greenville, NC 27858 (United States); Duff, John H. [U.S. Geological Survey, Menlo Park, CA 94025 (United States); Ramírez, Alonso [Department of Environmental Sciences, University of Puerto Rico, San Juan, PR 00931 (Puerto Rico); Small, Gaston E. [Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108 (United States); Jackman, Alan P. [University of California, Davis, CA 95616 (United States); Triska, Frank J. [U.S. Geological Survey, Menlo Park, CA 94025 (United States); Pringle, Catherine M. [Odum School of Ecology, University of Georgia, Athens, GA 30602 (United States)

2013-01-15

Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (∼ 6) than streams that do not receive IGF (pH ∼ 5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO{sub 3}{sup −}) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO{sub 3}{sup −} was an important buffering mechanism in both streams. Base cation, Fe{sup 2+}, and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and

Effects of riparian buffers on hydrology of northern seasonal ponds

Science.gov (United States)

Randall K. Kolka; Brian J. Palik; Daniel P. Tersteeg; James C. Bell

2011-01-01

Although seasonal ponds are common in northern, glaciated, forested landscapes, forest management guidelines are generally lacking for these systems. The objective of this study was to determine the effect of riparian buffer type on seasonal pond hydrology following harvest of the adjacent upland forest. A replicated block design consisting of four buffer treatments...

Evaluation of sonication treatment and buffer composition on rumen bacteria protein extraction and carboxymethylcellulase activity.

Science.gov (United States)

Prauchner, Carlos A; Kozloski, Gilberto V; Farenzena, Roberta

2013-05-01

The methodological procedures for studying the fibrolytic activity of rumen bacteria are not clearly established. In this study the efficiency of sonication treatment and buffer composition (i.e. buffer varying in tonicity or pH) on the level of protein extraction from the residue of forage samples incubated in the rumen of a grazing steer and the effect of buffer composition or CaCl₂ concentration on the carboxymethylcellulase (CMCase) activity of the released protein were evaluated. The amount of protein released from the residue of incubation was higher (P buffer pH (P buffer. Both linear and quadratic effects (P buffer pH on CMCase activity were significant, with CMCase activity being maximal at pH 5.4-6.1. CMCase activity was higher (P buffer solution that includes a calcium source. When pH is not a treatment factor, the buffer pH should be between 5.5 and 6. © 2012 Society of Chemical Industry.

Charge movement in a GaN-based hetero-structure field effect transistor structure with carbon doped buffer under applied substrate bias

International Nuclear Information System (INIS)

Pooth, Alexander; Uren, Michael J.; Cäsar, Markus; Kuball, Martin; Martin, Trevor

2015-01-01

Charge trapping and transport in the carbon doped GaN buffer of a GaN-based hetero-structure field effect transistor (HFET) has been investigated under both positive and negative substrate bias. Clear evidence of redistribution of charges in the carbon doped region by thermally generated holes is seen, with electron injection and capture observed during positive bias. Excellent agreement is found with simulations. It is shown that these effects are intrinsic to the carbon doped GaN and need to be controlled to provide reliable and efficient GaN-based power HFETs

Biomimetic Nanohydroxyapatite Synthesized With/Without Tris-Buffered Simulated Body Fluid: A Comparative Analysis.

Science.gov (United States)

Rana, Deepti; Wang, Xiumei; Webster, Thomas J; Ramalingam, Murugan

2018-06-01

Nano hydroxyapatite (nHAp) mimics the inorganic phase of hard tissue such as bone and teeth and, thus, has a wide range of clinical applications. The present study reports on the biomimetic synthesis of nHAp with and without Tris-buffered simulated body fluid (SBF) and investigated the role of buffering conditions on nHAp formation. The hypothesis of this study was that the nucleation and growth rate of nHAp may depend on buffering conditions during the precipitation process. The results of this study suggest that both of the above methods effectively synthesized carbonated "bone-like" nHAp. However, an increased incubation period of 8 hrs was necessary for nHAp synthesized using non Tris-buffered SBF as compared to Tris-buffered SBF which synthesized nHAp in just 3 hrs. Interestingly, there was no change in the chemical functionality for both samples. XRD and TGA analysis confirmed that Tris-buffered SBF facilitated more carbonate ion substitution than the non-Tris-buffered SBF approach. Therefore, this study concluded for the first time that the addition of Tris in SBF accelerates nHAp formation with more carbonate ion substitution. Nevertheless, carbonate ion substituted nHAp could also be synthesized using non Tris-buffered SBF, but would require longer incubation periods. This analysis highlights the importance of pH stability in the SBF for biomimetic nHAp synthesis which is useful for the synthesis of nHAp for a wide range of biomedical applications.

Coupled transport/reaction model of the properties of bentonite buffer in a repository

International Nuclear Information System (INIS)

Liu, Jinsong; Neretnieks, I.

1996-11-01

Two mechanisms that can affect the long-term properties of the bentonite buffer surrounding the canister in a final repository of spent nuclear fuel are studied. The two mechanisms are the oxidation of reducing minerals in the buffer by radiolytically generated oxidant, and the low-temperature alteration of Na-montmorillonite in the bentonite buffer to illite. A coupled mass transport with geochemical reaction model is used. Four cases have been considered, which differ in the assumptions of whether the radiolytically generated oxidant first oxidizes uraninite in the spent fuel, or it is directly transported to the bentonite to oxidize the pyrite. The cases also differ in the assumptions of varying initial concentrations of pyrite in the bentonite buffer. The modelling results show that, at low temperatures, the sodium montmorillonite in the bentonite buffer is chemically stable with respect to the chemical conditions of the near field. Alteration to illite and thus an increase in hydraulic conductivity and loss of swelling ability is not likely to occur. The radiolytically generated oxidant can possibly oxidize the reducing minerals in the bentonite buffer. A redox front can be generated. In all the cases considered in this study, the modelling results indicate that slightly less than 1% by weight of pyrite in the bentonite buffer will be able to ensure that the redox front does not penetrate through the bentonite buffer within 1 million years. 31 refs

Application Of The Work Breakdown Structure In Determining Cost Buffers In Construction Schedules

Directory of Open Access Journals (Sweden)

Połoński M.

2015-03-01

Full Text Available The paper presents methods of determining the location of cost buffers and corresponding contingency costs in the CPM schedule based on its work breakdown structure. Application of correctly located cost buffers with appropriately established reserve costs is justified by the common overrunning of scheduled costs in construction projects. Interpolated cost buffers (CB as separate tasks have been combined with relevant summary tasks by the start–to–start (SS relationship, whereas the time of their execution has been dynamically connected with the time of accomplishment of particular summary tasks using the “paste connection” option. Besides cost buffers linked with the group of tasks assigned to summary tasks, a definition of the cost buffer for the entire project (PCB has been proposed, i.e. as one initial task of the entire project. Contingency costs corresponding to these buffers, depending on the data that the planner has at his disposal, can be determined using different methods, but always depend on the costs of all tasks protected by each buffer. The paper presents an exemplary schedule for a facility and the method of determining locations and cost for buffers CB and PCB, as well as their influence on the course of the curve illustrating the budgeted cost of work scheduled (BCWS. The proposed solution has been adjusted and presented with consideration of the possibilities created by the scheduling software MS Project, though its general assumptions may be implemented with application of other similar specialist tools.

A Unified Buffering Management with Set Divisible Cache for PCM Main Memory

Institute of Scientific and Technical Information of China (English)

Mei-Ying Bian; Su-Kyung Yoon; Jeong-Geun Kim; Sangjae Nam; Shin-Dug Kim

2016-01-01

This research proposes a phase-change memory (PCM) based main memory system with an effective combi-nation of a superblock-based adaptive buffering structure and its associated set divisible last-level cache (LLC). To achieve high performance similar to that of dynamic random-access memory (DRAM) based main memory, the superblock-based adaptive buffer (SABU) is comprised of dual DRAM buffers, i.e., an aggressive superblock-based pre-fetching buffer (SBPB) and an adaptive sub-block reusing buffer (SBRB), and a set divisible LLC based on a cache space optimization scheme. According to our experiment, the longer PCM access latency can typically be hidden using our proposed SABU, which can significantly reduce the number of writes over the PCM main memory by 26.44%. The SABU approach can reduce PCM access latency up to 0.43 times, compared with conventional DRAM main memory. Meanwhile, the average memory energy consumption can be reduced by 19.7%.

E-model MOS Estimate Improvement through Jitter Buffer Packet Loss Modelling

Directory of Open Access Journals (Sweden)

Adrian Kovac

2011-01-01

Full Text Available Proposed article analyses dependence of MOS as a voice call quality (QoS measure estimated through ITU-T E-model under real network conditions with jitter. In this paper, a method of jitter effect is proposed. Jitter as voice packet time uncertainty appears as increased packet loss caused by jitter memory buffer under- or overflow. Jitter buffer behaviour at receiver’s side is modelled as Pareto/D/1/K system with Pareto-distributed packet interarrival times and its performance is experimentally evaluated by using statistic tools. Jitter buffer stochastic model is then incorporated into E-model in an additive manner accounting for network jitter effects via excess packet loss complementing measured network packet loss. Proposed modification of E-model input parameter adds two degrees of freedom in modelling: network jitter and jitter buffer size.

Study on chemical buffering property of GMZ sodium bentonite in air

International Nuclear Information System (INIS)

Wen Zhijian; Liu Yuemiao; Zong Zihua; Zhou Jia

2008-01-01

The high level radioactive wastes are characterized by very high initial radioactivity, the longer-lived actinides, many of actinides alpha-emitters. At present, the deep geological disposal is regarded as the most reasonable and effective way to safely disposal high-level radioactive wastes in the world. The conceptual model of HLW geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the engineered barrier materials and GMZ Na-bentonite is selected as the base material. The most important role related to buffer is chemical buffering, which means buffering of changes in water chemistry. This paper presents the experiments of GMZ-1 Na-bentonite reacted with distilled water in the air. The results and discussion of bench tests are reported. (authors)

Diffusivity database (DDB) system for major rocks and buffer materials (Released on 2007/specification)

International Nuclear Information System (INIS)

Tochigi, Yoshikatsu; Shibata, Masahiro; Sato, Haruo; Kitamura, Akira

2007-03-01

The Diffusivity Database (DDB) System developed on early 2006 was upgraded to apply the data of effective diffusion coefficient of the nuclides in the rock matrix for the 'H12: Project to Establish the Scientific and Technical Basis for HLW Disposal in Japan', and the data in the buffer materials from literature survey was newly added. Some functions of data search and selection were reformed to improve the level of convenience. This DDB system (work on MS-Access TM ) is released to the public through Web server managed by JAEA. (author)

Thermochemical parameters of minerals from oxygen-buffered hydrothermal equilibrium data: Method, application to annite and almandine

Science.gov (United States)

Zen, E.-A.

1973-01-01

Reversed univariant hydrothermal phase-equilibrium reactions, in which a redox reaction occurs and is controlled by oxygen buffers, can be used to extract thermochemical data on minerals. The dominant gaseous species present, even for relatively oxidizing buffers such as the QFM buffer, are H2O and H2; the main problem is to calculate the chemical potentials of these components in a binary mixture. The mixing of these two species in the gas phase was assumed by Eugster and Wones (1962) to be ideal; this assumption allows calculation of the chemical potentials of the two components in a binary gas mixture, using data in the literature. A simple-mixture model of nonideal mixing, such as that proposed by Shaw (1967), can also be combined with the equations of state for oxygen buffers to permit derivation of the chemical potentials of the two components. The two mixing models yield closely comparable results for the more oxidizing buffers such as the QFM buffer. For reducing buffers such as IQF, the nonideal-mixing correction can be significant and the Shaw model is better. The procedure of calculation of mineralogical thermochemical data, in reactions where hydrogen and H2O simultaneously appear, is applied to the experimental data on annite, given by Wones et al. (1971), and on almandine, given by Hsu (1968). For annite the results are: Standard entropy of formation from the elements, Sf0 (298, 1)=-283.35??2.2 gb/gf, S0 (298, 1) =+92.5 gb/gf. Gf0 (298, 1)=-1148.2??6 kcal, and Hf0 (298, 1)=-1232.7??7 kcal. For almandine, the calculation takes into account the mutual solution of FeAl2O4 (Hc) in magnetite and of Fe3O4 (Mt) in hercynite and the temperature dependence of this solid solution, as given by Turnock and Eugster (1962); the calculations assume a regular-solution model for this binary spinel system. The standard entropy of formation of almandine, Sf,A0 (298, 1) is -272.33??3 gb/gf. The third law entropy, S0 (298, 1) is +68.3??3 gb/gf, a value much less than the

Buffer sizing for multi-hop networks

KAUST Repository

Shihada, Basem; Jamshaid, Kamran

2014-01-01

domain according to a simple division or according to a cost function taking into account a distance of the communications link from the source and destination. The network may be monitored and the cumulative buffer size recalculated and redistributed

Final Report for File System Support for Burst Buffers on HPC Systems

Energy Technology Data Exchange (ETDEWEB)

Yu, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mohror, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-11-27

Distributed burst buffers are a promising storage architecture for handling I/O workloads for exascale computing. As they are being deployed on more supercomputers, a file system that efficiently manages these burst buffers for fast I/O operations carries great consequence. Over the past year, FSU team has undertaken several efforts to design, prototype and evaluate distributed file systems for burst buffers on HPC systems. These include MetaKV: a Key-Value Store for Metadata Management of Distributed Burst Buffers, a user-level file system with multiple backends, and a specialized file system for large datasets of deep neural networks. Our progress for these respective efforts are elaborated further in this report.

On the risk of liquefaction of buffer and backfill

Energy Technology Data Exchange (ETDEWEB)

Pusch, R. [Geodevelopment AB, Lund (Sweden)

2000-10-01

The necessary prerequisites for liquefaction of buffers and backfills in a KBS-3 repository exist but the stress conditions and intended densities practically eliminate the risk of liquefaction for single earthquakes with magnitudes up to M=8 and normal duration. For buffers rich in expandable minerals it would be possible to reduce the density at water saturation to 1,700 - 1,800 kg/m{sup 3} or even less without any significant risk of liquefaction, while the density at saturation of backfills with 10 - 15% expandable clay should not be reduced to less than about 1,900 kg/m{sup 3}. Since the proposed densities of both buffers and backfills will significantly exceed these minimum values it is concluded that there is no risk of liquefaction of the engineered soil barriers in a KBS-3 repository even for very significant earthquakes.

On the risk of liquefaction of buffer and backfill

International Nuclear Information System (INIS)

Pusch, R.

2000-10-01

The necessary prerequisites for liquefaction of buffers and backfills in a KBS-3 repository exist but the stress conditions and intended densities practically eliminate the risk of liquefaction for single earthquakes with magnitudes up to M=8 and normal duration. For buffers rich in expandable minerals it would be possible to reduce the density at water saturation to 1,700 - 1,800 kg/m 3 or even less without any significant risk of liquefaction, while the density at saturation of backfills with 10 - 15% expandable clay should not be reduced to less than about 1,900 kg/m 3 . Since the proposed densities of both buffers and backfills will significantly exceed these minimum values it is concluded that there is no risk of liquefaction of the engineered soil barriers in a KBS-3 repository even for very significant earthquakes

Clay colloid formation and release from MX-80 buffer

International Nuclear Information System (INIS)

Pusch, R.

1999-12-01

Flowing groundwater can tear off clay colloids from buffer clay that has penetrated into fractures and transport them and bring sorbed radionuclides up to the biosphere. The colloids are 2-50 μm particle aggregates that are liberated from expanded, softened buffer if the water flow rate in the fractures exceeds a few centimeters per second. Except for the first few months or years after application of the buffer in the deposition holes the flow rate will not be as high as that. The aperture of the fractures will not hinder transport of colloids but most of the fractures contain clastic fillings, usually chlorite, that attract and immobilize them. This condition and the flow rate criterion combine to reduce the chance of radionuclide-bearing clay colloids to reach the biosphere to practically zero except for certain cases that need to be considered

Variation of power generation at different buffer types and conductivities in single chamber microbial fuel cells

KAUST Repository

Nam, Joo-Youn

2010-01-15

Microbial fuel cells (MFCs) are operated with solutions containing various chemical species required for the growth of electrochemically active microorganisms including nutrients and vitamins, substrates, and chemical buffers. Many different buffers are used in laboratory media, but the effects of these buffers and their inherent electrolyte conductivities have not been examined relative to current generation in MFCs. We investigated the effect of several common buffers (phosphate, MES, HEPES, and PIPES) on power production in single chambered MFCs compared to a non-buffered control. At the same concentrations the buffers produced different solution conductivities which resulted in different ohmic resistances and power densities. Increasing the solution conductivities to the same values using NaCl produced comparable power densities for all buffers. Very large increases in conductivity resulted in a rapid voltage drop at high current densities. Our results suggest that solution conductivity at a specific pH for each buffer is more important in MFC studies than the buffer itself given relatively constant pH conditions. Based on our analysis of internal resistance and a set neutral pH, phosphate and PIPES are the most useful buffers of those examined here because pH was maintained close to the pKa of the buffer, maximizing the ability of the buffer to contribute to increase current generation at high power densities. © 2009 Elsevier B.V. All rights reserved.

Variation of power generation at different buffer types and conductivities in single chamber microbial fuel cells.

Science.gov (United States)

Nam, Joo-Youn; Kim, Hyun-Woo; Lim, Kyeong-Ho; Shin, Hang-Sik; Logan, Bruce E

2010-01-15

Microbial fuel cells (MFCs) are operated with solutions containing various chemical species required for the growth of electrochemically active microorganisms including nutrients and vitamins, substrates, and chemical buffers. Many different buffers are used in laboratory media, but the effects of these buffers and their inherent electrolyte conductivities have not been examined relative to current generation in MFCs. We investigated the effect of several common buffers (phosphate, MES, HEPES, and PIPES) on power production in single chambered MFCs compared to a non-buffered control. At the same concentrations the buffers produced different solution conductivities which resulted in different ohmic resistances and power densities. Increasing the solution conductivities to the same values using NaCl produced comparable power densities for all buffers. Very large increases in conductivity resulted in a rapid voltage drop at high current densities. Our results suggest that solution conductivity at a specific pH for each buffer is more important in MFC studies than the buffer itself given relatively constant pH conditions. Based on our analysis of internal resistance and a set neutral pH, phosphate and PIPES are the most useful buffers of those examined here because pH was maintained close to the pK(a) of the buffer, maximizing the ability of the buffer to contribute to increase current generation at high power densities. Copyright 2009 Elsevier B.V. All rights reserved.

EnviroAtlas - Paterson, NJ - 51m Riparian Buffer Forest Cover

Science.gov (United States)

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the riparian buffer is less forested. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the Atlas Area. EnviroAtlas defines tree buffer for this community as only trees and forest. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

Resolution doubling in 3D-STORM imaging through improved buffers.

Science.gov (United States)

Olivier, Nicolas; Keller, Debora; Gönczy, Pierre; Manley, Suliana

2013-01-01

Super-resolution imaging methods have revolutionized fluorescence microscopy by revealing the nanoscale organization of labeled proteins. In particular, single-molecule methods such as Stochastic Optical Reconstruction Microscopy (STORM) provide resolutions down to a few tens of nanometers by exploiting the cycling of dyes between fluorescent and non-fluorescent states to obtain a sparse population of emitters and precisely localizing them individually. This cycling of dyes is commonly induced by adding different chemicals, which are combined to create a STORM buffer. Despite their importance, the composition of these buffers has scarcely evolved since they were first introduced, fundamentally limiting what can be resolved with STORM. By identifying a new chemical suitable for STORM and optimizing the buffer composition for Alexa-647, we significantly increased the number of photons emitted per cycle by each dye, providing a simple means to enhance the resolution of STORM independently of the optical setup used. Using this buffer to perform 3D-STORM on biological samples, we obtained images with better than 10 nanometer lateral and 30 nanometer axial resolution.

Resolution doubling in 3D-STORM imaging through improved buffers.

Directory of Open Access Journals (Sweden)

Nicolas Olivier

Full Text Available Super-resolution imaging methods have revolutionized fluorescence microscopy by revealing the nanoscale organization of labeled proteins. In particular, single-molecule methods such as Stochastic Optical Reconstruction Microscopy (STORM provide resolutions down to a few tens of nanometers by exploiting the cycling of dyes between fluorescent and non-fluorescent states to obtain a sparse population of emitters and precisely localizing them individually. This cycling of dyes is commonly induced by adding different chemicals, which are combined to create a STORM buffer. Despite their importance, the composition of these buffers has scarcely evolved since they were first introduced, fundamentally limiting what can be resolved with STORM. By identifying a new chemical suitable for STORM and optimizing the buffer composition for Alexa-647, we significantly increased the number of photons emitted per cycle by each dye, providing a simple means to enhance the resolution of STORM independently of the optical setup used. Using this buffer to perform 3D-STORM on biological samples, we obtained images with better than 10 nanometer lateral and 30 nanometer axial resolution.

High-throughput and multiplexed regeneration buffer scouting for affinity-based interactions

NARCIS (Netherlands)

Geuijen, K.P.M.; Schasfoort, R.B.; Wijffels, R.H.; Eppink, M.H.M.

2014-01-01

Affinity-based analyses on biosensors depend partly on regeneration between measurements. Regeneration is performed with a buffer that efficiently breaks all interactions between ligand and analyte while maintaining the active binding site of the ligand. We demonstrated a regeneration buffer

Effect of a cathode buffer layer on the stability of organic solar cells

International Nuclear Information System (INIS)

Wang, Danbei; Zeng, Wenjin; Chen, Shilin; Su, Xiaodan; Wang, Jin; Zhang, Hongmei

2015-01-01

We present the effect of a cathode buffer layer on the performance and stability of organic photovoltaics (OPVs) based on a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Six kinds of cathode buffer layers, i.e. lithium fluoride, sodium chloride, NaCl/Mg, tris-(8-hydroxy-quinoline) aluminum, bathocuproine and 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene, were inserted between the photoactive layer and an Al cathode, which played a dominant role in the device’s performance. Devices with the cathode buffer layers above exhibited improved performance. The degradation of these devices with encapsulation was further investigated in an inert atmosphere. The results indicated that devices with inorganic cathode buffer layers exhibited better stability than those with organic cathode buffer layers. (paper)

Establishing the concept of buffer for a high-level radioactive waste repository: An approach

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae Owan; Lee, Min Soo; Choi, Heui Joo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-12-15

The buffer is a key component of the engineered barrier system in a high-level radioactive waste (HLW) repository. The present study reviewed the requirements and functional criteria of the buffer reported in literature, and also based on the results, proposed an approach to establish a buffer concept which is applicable to an HLW repository in Korea. The hydraulic conductivity, radionuclide-retarding capacity (equilibrium distribution coefficient and diffusion coefficient), swelling pressure, thermal conductivity, mechanical properties, organic carbon content, and initialization rate were considered as major technical parameters for the functional criteria of the buffer. Domestic bentonite (Ca-bentonite) and, as an alternative, MX-80 (Na-bentonite) were proposed for the buffer of an HLW repository in Korea. The technical specifications for those proposed bentonites were set to parameter values that conservatively satisfy Korea's functional criteria for the Ca-bentonite and Swedish criteria for the Na-bentonite. The thickness of the buffer was determined by evaluating the means of shear behavior, radionuclide release, and heat conduction, which resulted in the proper buffer thickness of 0.25 to 0.5 m. However, the final thickness of the buffer should be determined by considering coupled thermal-hydraulic-mechanical evaluation and economics and engineering aspects as well.

Buffer AVL Alone Does Not Inactivate Ebola Virus in a Representative Clinical Sample Type.

Science.gov (United States)

Smither, Sophie J; Weller, Simon A; Phelps, Amanda; Eastaugh, Lin; Ngugi, Sarah; O'Brien, Lyn M; Steward, Jackie; Lonsdale, Steve G; Lever, Mark S

2015-10-01

Rapid inactivation of Ebola virus (EBOV) is crucial for high-throughput testing of clinical samples in low-resource, outbreak scenarios. The EBOV inactivation efficacy of Buffer AVL (Qiagen) was tested against marmoset serum (EBOV concentration of 1 × 10(8) 50% tissue culture infective dose per milliliter [TCID50 · ml(-1)]) and murine blood (EBOV concentration of 1 × 10(7) TCID50 · ml(-1)) at 4:1 vol/vol buffer/sample ratios. Posttreatment cell culture and enzyme-linked immunosorbent assay (ELISA) analysis indicated that treatment with Buffer AVL did not inactivate EBOV in 67% of samples, indicating that Buffer AVL, which is designed for RNA extraction and not virus inactivation, cannot be guaranteed to inactivate EBOV in diagnostic samples. Murine blood samples treated with ethanol (4:1 [vol/vol] ethanol/sample) or heat (60°C for 15 min) also showed no viral inactivation in 67% or 100% of samples, respectively. However, combined Buffer AVL and ethanol or Buffer AVL and heat treatments showed total viral inactivation in 100% of samples tested. The Buffer AVL plus ethanol and Buffer AVL plus heat treatments were also shown not to affect the extraction of PCR quality RNA from EBOV-spiked murine blood samples. © Crown copyright 2015.

Buffer layer annealing effects on the magnetization reversal process in Pd/Co/Pd systems

International Nuclear Information System (INIS)

Fassatoui, A.; Belhi, R.; Vogel, J.; Abdelmoula, K.

2016-01-01

We have investigated the effect of annealing the buffer layer on the magnetization reversal behavior in Pd/Co/Pd thin films using magneto-optical Kerr microscopy. It was found that annealing the buffer layer at 150 °C for 1 h decreases the coercivity and increases the saturation magnetization and the effective magnetic anisotropy constant. This study also shows that the annealing induces a change of the magnetization reversal from a mixed nucleation and domain wall propagation process to one dominated by domain wall propagation. This result demonstrates that the main effect of annealing the buffer layer is to decrease the domain wall pinning in the Co layer, favoring the domain wall propagation mode. - Highlights: • The buffer layer surface morphology changes upon annealing of the buffer layer. • The coercivity decreases while the saturation magnetization and the effective anisotropy increase with the annealing of the buffer layer. • The reversal process changes from a mixed nucleation and domain wall propagation process to one dominated by domain wall propagation when annealing the buffer layer.

Growth and characterization of semi-insulating carbon-doped/undoped GaN multiple-layer buffer

International Nuclear Information System (INIS)

Kim, Dong-Seok; Won, Chul-Ho; Kang, Hee-Sung; Kim, Young-Jo; Kang, In Man; Lee, Jung-Hee; Kim, Yong Tae

2015-01-01

We have proposed a new semi-insulating GaN buffer layer, which consists of multiple carbon-doped and undoped GaN layer. The buffer layer showed sufficiently good semi-insulating characteristics, attributed to the depletion effect between the carbon-doped GaN and the undoped GaN layers, even though the thickness of the carbon-doped GaN layer in the periodic structure was designed to be very thin to minimize the total carbon incorporation into the buffer layer. The AlGaN/AlN/GaN heterostructure grown on the proposed buffer exhibited much better electrical and structural properties than that grown on the conventional thick carbon-doped semi-insulating GaN buffer layer, confirmed by Hall measurement, x-ray diffraction, and secondary ion mass spectrometry. The fabricated device also showed excellent buffer breakdown characteristics. (paper)

The buffering-out effect and phase separation in aqueous solutions of EPPS buffer with 1-propanol, 2-propanol, or 2-methyl-2-propanol at T = 298.15 K

International Nuclear Information System (INIS)

Taha, Mohamed; Teng, Han-Lan; Lee, Ming-Jer

2012-01-01

Highlights: ► Buffering-out is a new liquid–liquid phase separation containing biological buffer. ► EPPS buffer-induced phase separation of aqueous solutions of aliphatic alcohols. ► Phase diagrams of EPPS + water + 1-propanol/2-propanol/2-methyl-2-propanol are studied. ► EPPS breaks the 1-propanol + water and 2-methyl-2-propanol + water azeotropes. ► The (liquid + liquid) equilibria can be well correlated by the NRTL model. - Abstract: Buffering-out is a new liquid–liquid phase separation phenomenon observed in mixtures containing a buffer as a mass separating agent. The (liquid + liquid) equilibrium (LLE) and (solid + liquid + liquid) equilibrium (SLLE) data were measured for the ternary systems {3-[4-(2-hydroxyethyl)piperazin-1-yl]propanesulfonic acid (EPPS) buffer + 1-propanol, 2-propanol, or 2-methyl-2-propanol + water} at T = 298.15 K under atmospheric pressure. The phase boundary data were fitted to an empirical equation relating to the concentrations of organic solvent and buffer. The effective excluded volume (EEV) values of EPPS were obtained from the phase boundary data. The phase-separation abilities of the investigated aliphatic alcohols were discussed. The reliability of the experimental tie-lines was satisfactorily confirmed by the Othmer–Tobias correlation. The experimental tie-lines data for the ternary systems have been correlated using the NRTL activity coefficient model. The separation of these aliphatic alcohols from their azeotropic aqueous mixtures is of particular interest to industrial process. The addition of the EPPS as an auxiliary agent breaks the (1-propanol + water) and (2-methyl-2-propanol + water) azeotropes. The possibility of using the new phase separation systems in the extraction process is demonstrated by using different dyestuffs.

α-Helix Unwinding as Force Buffer in Spectrins.

Science.gov (United States)

Takahashi, Hirohide; Rico, Felix; Chipot, Christophe; Scheuring, Simon

2018-03-27

Spectrins are cytoskeletal proteins located at the inner face of the plasma membrane, making connections between membrane anchors and the actin cortex, and between actin filaments. Spectrins share a common structure forming a bundle of 3 α-helices and play a major role during cell deformation. Here, we used high-speed force spectroscopy and steered molecular dynamics simulations to understand the mechanical stability of spectrin, revealing a molecular force buffering function. We find that spectrin acts as a soft spring at short extensions (70-100 Å). Under continuous external stretching, its α-helices unwind, leading to a viscous mechanical response over larger extensions (100-300 Å), represented by a constant-force plateau in force/extension curves. This viscous force buffering emerges from a quasi-equilibrium competition between disruption and re-formation of α-helical hydrogen bonds. Our results suggest that, in contrast to β-sheet proteins, which unfold in a catastrophic event, α-helical spectrins dominantly unwind, providing a viscous force buffer over extensions about 5 times their folded length.

Evaluation of buffers toxicity in tobacco cells: Homopiperazine-1,4-bis (2-ethanesulfonic acid) is a suitable buffer for plant cells studies at low pH.

Science.gov (United States)

Borgo, Lucélia

2017-06-01

Low pH is an important environmental stressor of plant root cells. Understanding the mechanisms of stress and tolerance to acidity is critical; however, there is no widely accepted pH buffer for studies of plant cells at low pH. Such a buffer might also benefit studies of Al toxicity, in which buffering at low pH is also important. The challenge is to find a buffer with minimal cellular effects. We examined the cytotoxicity and possible metabolic disturbances of four buffers that have adequate pK a values and potential use for studies in the pH range of 4.0-5.0. These were homopipes (homopiperazine-1,4-bis (2-ethanesulfonic acid); pK a1 4.4), 3,3-dimethylglutaric acid (pK a1 3.73), β-alanine (pK a1 3.70) and potassium biphthalate (pK a1 2.95; pK a2 5.41). First, tobacco BY-2 cells were grown in a rich medium containing 10 mM of each buffer or MES (2-(N-morpholino) ethanesulfonic acid) as a control, with the pH initially adjusted to 5.7. β-alanine was clearly toxic and dimethylgluturate and biphthalate were found to be cytostatic, in which no culture growth occurred but cell viability was either unaffected or decreased only after 5 days. Only homopipes allowed normal culture growth and cell viability. Homopipes (10 mM) was then tested in cell cultures with an initial pH of 4.3 ± 0.17 in minimal medium to examine whether its undissociated species (H 2 A) displayed any cellular effects and no cytotoxic effects were observed. It is possible to conclude that among tested buffers, homopipes is the most suitable for studies at low pH, and may be especially useful for aluminum toxicity experiments. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Geochemical modelling of hydrogen gas migration in an unsaturated bentonite buffer

NARCIS (Netherlands)

Sedighi, M.; Thomas, H.R.; Al Masum, S.; Vardon, P.J.; Nicholson, D.; Chen, Q.

2014-01-01

This paper presents an investigation of the transport and fate of hydrogen gas through compacted bentonite buffer. Various geochemical reactions that may occur in the multiphase and multicomponent system of the unsaturated bentonite buffer are considered. A reactive gas transport model, developed

Evaluation of amine inhibitors for suitability as crevice buffering agents

International Nuclear Information System (INIS)

Jayaweera, P.; Hettiarachchi, S.

1994-03-01

This report describes the results of a research effort to evaluate the suitability of some selected amines and amino acids as a crevice-buffering agents in pressurized water reactor (PWR) steam generators. The amines may be useful for buffering acid crevices, and the amino acids, because they contain both acidic and basic groups, may be useful for acidic and caustic crevices. Five commercially available amines and two amino acids were studied during this research. The study involved (1) the hydrolysis of these commercially available amines and amino acids, including measurement of their kinetics of decomposition, in simulated steam generator bulk water at 290 C, and (2) determination of their thermal stability in a simulated crevice environment. The study showed that, although the high-molecular-weight amines undergo hydrothermal decomposition, they have a better buffering capacity than their low-molecular-weight counterparts at 290 C. The amines provide effective crevice buffering by increasing the pH of the crevice solution by as much as 2.84 and to 4.24 units in the experimental setup used in this program. It was concluded that polyamines provide excellent buffering of the simulated crevice environment at 290 C and morpholine remains the best low-molecular-weight amine investigated. However, detailed volatility studies of the amines were not considered in this work. Such data would be needed before in-plant testing to ensure that the amines can concentrate in steam generator crevices to the levels assumed in this study

Are Capital Buffers Countercyclical ? An Evidence From Pakistan

Directory of Open Access Journals (Sweden)

Romila Qamar

2016-09-01

Full Text Available New risk based capital requirement have pro-cyclical effect and causes negative externalities in the economy. During recession, on one side, quality of loan portfolio deteriorates and probability of default increases resulting into increased level of provisions and write off’s and reduced capital level. This causes an increase in capital requirements which becomes more expensive. Weaker banks fail to access new capital and ultimately reduce the credit supply. On the other side, banks are required to maintain the minimum capital which results into credit supply contraction and hits the bank’s profitability leading to a situation called Credit Crunch. This situation may prolong recession. During the crisis, developing countries are more affected than developed countries and this debate is entirely new in Pakistan. This research empirically investigates the pro-cyclical effect of new capital regulation under Basel II using panel data of 47 Pakistani Banks from 2001-2012. Particularly this paper examines the capital management mechanisms using capital buffers, using Generalized Method of Moments (GMM one step and two step estimation techniques on dynamic panel data model. The results gives evidence that capital buffer are counter-cyclical except in case of specialized banks because of difference in operations. The findings also suggest that adjustment costs, cost of raising capital and bankruptcy costs are major determines of holding capital buffer. Analysis confirms too big to fail hypothesis. Form the results, it is concluded that capital buffer are counter-cyclical, consistent with the hypothesis. The findings suggest the banks to adopt Basel III Accord.

Transfer buffer containing methanol can be reused multiple times in protein electrotransfer.

Science.gov (United States)

Pettegrew, Colin J; Jayini, Renuka; Islam, M Rafiq

2009-04-01

We investigated the feasibility of repeated use of transfer buffer containing methanol in electrotransfer of proteins from sodium dodecyl sulfate-polyacrylamide gels to polyvinylidene difluoride (PVDF) membrane using a prestained protein marker of broad molecular sizes. Transfer of the antitumor protein p53 in HEK293T cell extracts, using fresh and used transfer buffer, followed by detection with anti-p53 antibody was also performed to test detectability in immunoblot. Results from these experiments indicate that the transfer buffer can be reused at least five times and maintain a similar extent of protein transfer to PVDF membrane. Repeated use of the transfer buffer containing methanol will significantly reduce the volume of hazardous waste generated and its disposal cost as well as its adverse effect on environment.

Heat buffers improve capacity and exploitation degree of geothermal energy sources

NARCIS (Netherlands)

Ooster, A.van t; Wit, J. de; Janssen, E.G.O.N.; Ruigrok, J.

2008-01-01

This research focuses on the role of heat buffers to support optimal use of combinations of traditional and renewable heat sources like geothermal heat for greenhouse heating. The objective was to determine the contribution of heat buffers to effective new combinations of resources that satisfy

Traveling waves in the discrete fast buffered bistable system.

Science.gov (United States)

Tsai, Je-Chiang; Sneyd, James

2007-11-01

We study the existence and uniqueness of traveling wave solutions of the discrete buffered bistable equation. Buffered excitable systems are used to model, among other things, the propagation of waves of increased calcium concentration, and discrete models are often used to describe the propagation of such waves across multiple cells. We derive necessary conditions for the existence of waves, and, under some restrictive technical assumptions, we derive sufficient conditions. When the wave exists it is unique and stable.

The effect of Cr buffer layer thickness on voltage generation of thin-film thermoelectric modules

International Nuclear Information System (INIS)

Mizoshiri, Mizue; Mikami, Masashi; Ozaki, Kimihiro

2013-01-01

The effect of Cr buffer layer thickness on the open-circuit voltage generated by thin-film thermoelectric modules of Bi 0.5 Sb 1.5 Te 3 (p-type) and Bi 2 Te 2.7 Se 0.3 (n-type) materials was investigated. A Cr buffer layer, whose thickness generally needs to be optimized to improve adhesion depending on the substrate surface condition, such as roughness, was deposited between thermoelectric thin films and glass substrates. When the Cr buffer layer was 1 nm thick, the Seebeck coefficients and electrical conductivity of 1 µm thermoelectric thin films with the buffer layers were approximately equal to those of the thermoelectric films without the buffer layers. When the thickness of the Cr buffer layer was 1 µm, the same as the thermoelectric films, the Seebeck coefficients of the bilayer films were reduced by an electrical current flowing inside the Cr buffer layer and the generation of Cr 2 Te 3 . The open-circuit voltage of the thin-film thermoelectric modules decreased with an increase in the thickness of the Cr buffer layer, which was primarily induced by the electrical current flow. The reduction caused by the Cr 2 Te 3 generation was less than 10% of the total voltage generation of the modules without the Cr buffer layers. The voltage generation of thin-film thermoelectric modules could be controlled by the Cr buffer layer thickness. (paper)

Assessment of polyelectrolyte coating stability under dynamic buffer conditions in CE.

Science.gov (United States)

Swords, Kyleen E; Bartline, Peter B; Roguski, Katherine M; Bashaw, Sarah A; Frederick, Kimberley A

2011-09-01

Dynamic buffer conditions are present in many electrophoretically driven separations. Polyelectrolyte multilayer coatings have been employed in CE because of their chemical and physical stability as well as their ease of application. The goal of this study is to measure the effect of dynamic changes in buffer pH on flow using a real-time method for measuring EOF. Polyelectrolyte multilayers (PEMs) were composed of pairs of strong or completely ionized polyelectrolytes including poly(diallyldimethylammonium) chloride and poly(styrene sulfonate) and weak or ionizable polyelectrolytes including poly(allylamine) and poly(methacrylic acid). Polyelectrolyte multilayers of varying thicknesses (3, 4, 7, 8, 15, or 16 layers) were also studied. While the magnitude of the EOF was monitored every 2 s, the buffer pH was exchanged from a relatively basic pH (7.1) to increasingly acidic pHs (6.6, 6.1, 5.5, and 5.1). Strong polyelectrolytes responded minimally to changes in buffer pH (10%) and sometimes irreversible changes were measured with weak polyelectrolytes. Thicker coatings resulted in a similar magnitude of response but were more likely to degrade in response to buffer pH changes. The most stable coatings were formed from thinner layers of strong polyelectrolytes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A buffer model of memory encoding and temporal correlations in retrieval.

Science.gov (United States)

Lehman, Melissa; Malmberg, Kenneth J

2013-01-01

Atkinson and Shiffrin's (1968) dual-store model of memory includes structural aspects of memory along with control processes. The rehearsal buffer is a process by which items are kept in mind and long-term episodic traces are formed. The model has been both influential and controversial. Here, we describe a novel variant of Atkinson and Shiffrin's buffer model within the framework of the retrieving effectively from memory theory (REM; Shiffrin & Steyvers, 1997) that accounts for findings previously thought to be difficult for such models to explain. This model assumes a limited-capacity buffer where information is stored about items, along with information about associations between items and between items and the context in which they are studied. The strength of association between items and context is limited by the number of items simultaneously occupying the buffer (Lehman & Malmberg, 2009). The contents of the buffer are managed by complementary processes of rehearsal and compartmentalization (Lehman & Malmberg, 2011). New findings that directly test a priori predictions of the model are reported, including serial position effects and conditional and first recall probabilities in immediate and delayed free recall, in a continuous distractor paradigm, and in experiments using list-length manipulations of single-item and paired-item study lists.

Chinese buffer material for high-level radiowaste disposal-basic features of GMZ-1

International Nuclear Information System (INIS)

Wen, Zhijian

2005-01-01

Radioactive wastes arising from a wide range of human activities are in many different physical and chemical forms, contaminated with varying radioactivity. Their common feature is the potential hazard associated with their radioactivity and the need to manage them in such a way as to protect the human environment. The geological disposal is regarded as the most reasonable and effective way to safety disposal high-level radioactive wastes in the world. The conceptual model of geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the main engineered barriers for HLW repository. The buffer material is expected to maintain its low water permeability, self-sealing property, radio nuclides adsorption and retardation property, thermal conductivity, chemical buffering property, overpack supporting property, stress buffering property over a long period of time. Bentonite is selected as the main content of buffer material that can satisfy above. GMZ deposit is selected as the candidate supplier for Chinese buffer material of High Level Radioactive waste repository. This paper presents geological features of GMZ deposit and basic property of GMZ Na bentonite. GMZ bentonite deposit is a super large scale deposits with high content of Montmorillonite (about 75%) and GMZ-1, which is Na-bentonite produced from GMZ deposit is selected as reference material for Chinese buffer material study

Impact of Burst Buffer Architectures on Application Portability

Energy Technology Data Exchange (ETDEWEB)

Harms, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Oral, H. Sarp [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Science; Atchley, Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Science; Vazhkudai, Sudharshan S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Science

2016-09-30

The Oak Ridge and Argonne Leadership Computing Facilities are both receiving new systems under the Collaboration of Oak Ridge, Argonne, and Livermore (CORAL) program. Because they are both part of the INCITE program, applications need to be portable between these two facilities. However, the Summit and Aurora systems will be vastly different architectures, including their I/O subsystems. While both systems will have POSIX-compliant parallel file systems, their Burst Buffer technologies will be different. This difference may pose challenges to application portability between facilities. Application developers need to pay attention to specific burst buffer implementations to maximize code portability.

Buffer thermal energy storage for an air Brayton solar engine

Science.gov (United States)

Strumpf, H. J.; Barr, K. P.

1981-01-01

The application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine was studied. To demonstrate the effect of buffer thermal energy storage on engine operation, a computer program was written which models the recuperator, receiver, and thermal storage device as finite-element thermal masses. Actual operating or predicted performance data are used for all components, including the rotating equipment. Based on insolation input and a specified control scheme, the program predicts the Brayton engine operation, including flows, temperatures, and pressures for the various components, along with the engine output power. An economic parametric study indicates that the economic viability of buffer thermal energy storage is largely a function of the achievable engine life.

There is no capacity limited buffer in the Murdock (1962) free recall data

OpenAIRE

Tarnow, Eugen

2010-01-01

Theories of short term memory often include a limited capacity “buffer”. Such a buffer contains items which do not decay at all but are overwritten by new data. I show that one of the experiments that fueled the buffer concept, the free recall experiments by Murdock (J Exp Psychol 64(5):482–488, 1962), does not contain such a buffer.

Coupled microrings data buffer using fast light

Science.gov (United States)

Scheuer, Jacob; Shahriar, Selim

2013-03-01

We present a theoretical study of a trap-door optical buffer based on a coupled microrings add/drop filter (ADF) utilizing the white light cavity (WLC). The buffer "trap-door" can be opened and closed by tuning the resonances of the microrings comprising the ADF and trap/release optical pulses. We show that the WLC based ADF yields a maximally flat filter which exhibits superior performances in terms of bandwidth and flatness compared to previous design approaches. We also present a realistic, Silicon-over-Insulator based, design and performance analysis taking into consideration the realistic properties and limitations of the materials and the fabrication process, leading to delays exceeding 850ps for 80GHz bandwidth, and a corresponding delay-bandwidth product of approximately 70.

Natively textured surface hydrogenated gallium-doped zinc oxide transparent conductive thin films with buffer layers for solar cells

Energy Technology Data Exchange (ETDEWEB)

Chen, Xin-liang, E-mail: cxlruzhou@163.com; Wang, Fei; Geng, Xin-hua; Huang, Qian; Zhao, Ying; Zhang, Xiao-dan

2013-09-02

Natively textured surface hydrogenated gallium-doped zinc oxide (HGZO) thin films have been deposited via magnetron sputtering on glass substrates. These natively textured HGZO thin films exhibit rough pyramid-like textured surface, high optical transmittances in the visible and near infrared region and excellent electrical properties. The experiment results indicate that tungsten-doped indium oxide (In{sub 2}O{sub 3}:W, IWO) buffer layers can effectively improve the surface roughness and enhance the light scattering ability of HGZO thin films. The root-mean-square roughness of HGZO, IWO (10 nm)/HGZO and IWO (30 nm)/HGZO thin films are 28, 44 and 47 nm, respectively. The haze values at the wavelength of 550 nm increase from 7.0% of HGZO thin film without buffer layer to 18.37% of IWO (10 nm)/HGZO thin film. The optimized IWO (10 nm)/HGZO exhibits a high optical transmittance of 82.18% in the visible and near infrared region (λ ∼ 400–1100 nm) and excellent electrical properties with a relatively low sheet resistance of 3.6 Ω/□ and the resistivity of 6.21 × 10{sup −4} Ωcm. - Highlights: • Textured hydrogenated gallium-doped zinc oxide (HGZO) films were developed. • Tungsten-doped indium oxide (IWO) buffer layers were applied for the HGZO films. • Light-scattering ability of the HGZO films can be improved through buffer layers. • Low sheet resistance and high haze were obtained for the IWO(10 nm)/HGZO film. • The IWO/HGZO films are promising transparent conductive layers for solar cells.

ROBUST: The ROle of BUffering capacities in STabilising coastal lagoon ecosystems

NARCIS (Netherlands)

De Wit, R.; Stal, L.J.; Lomstein, B.A.; Herbert, R.A.; van Gemerden, H.; Viaroli, P.; Cecherelli, V.U.; Rodriguez-Valera, F.; Bartoli, M.; Giordani, G.; Azzoni, R.; Schaub, B.; Welsh, D.T.; Donnelly, A.; Cifuentes, A.; Anton, J.; Finster, K.; Nielsen, L.P.; Pedersen, A.G.U.; Neubauer, A.T.; Colangelo, M.A.; Heijs, S.K.

2001-01-01

"Buffer capacities" has been defined in ecology as a holistic concept (e.g., Integration of Ecosystem Theories: A Pattern, second ed. Kluwer, Dordrecht, 1997, 388pp), but we show that it can also be worked out in mechanistic studies. Our mechanistic approach highlights that "buffering capacities"

ROBUST : The ROle of BUffering capacities in STabilising coastal lagoon ecosystems

NARCIS (Netherlands)

de Wit, R; Stal, LJ; Lomstein, BA; Herbert, RA; van Gemerden, H; Viaroli, P; Cecherelli, VU; Rodriguez-Valera, F; Bartoli, M; Giordani, G; Azzoni, R; Schaub, B; Welsh, DT; Donnelly, A; Cifuentes, A; Anton, J; Finster, K; Nielsen, LB; Pedersen, AGU; Neubauer, AT; Colangelo, MA; Heijs, SK

2001-01-01

"Buffer capacities" has been defined in ecology as a holistic concept (e.g., Integration of Ecosystem Theories: A Pattern, second ed. Kluwer, Dordrecht, 1997, 388pp), but we show that it can also be worked out in mechanistic studies. Our mechanistic approach highlights that "buffering capacities"

On the Stability of DNA Origami Nanostructures in Low-Magnesium Buffers.

Science.gov (United States)

Kielar, Charlotte; Xin, Yang; Shen, Boxuan; Kostiainen, Mauri A; Grundmeier, Guido; Linko, Veikko; Keller, Adrian

2018-05-25

DNA origami have great potential as functional platforms in various biomedical applications. Many applications, however, are incompatible with the high Mg2+ concentrations commonly believed to be a prerequisite for maintaining DNA origami integrity. Here, we investigate DNA origami stability in low-Mg2+ buffers. DNA origami stability is found to crucially depend on the availability of residual Mg2+ ions for screening electrostatic repulsion. The presence of EDTA and phosphate ions may thus facilitate DNA origami denaturation by displacing Mg2+ ions from the DNA backbone and reducing the strength of the Mg2+-DNA interaction, respectively. Most remarkably, these buffer dependencies are affected by DNA origami superstructure. However, by rationally selecting buffer components and considering superstructure-dependent effects, the structural integrity of a given DNA origami nanostructure can be maintained in conventional buffers even at Mg2+ concentrations in the low-μM range. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Smoothing type buffer memory device

International Nuclear Information System (INIS)

Podorozhnyj, D.M.; Yashin, I.V.

1990-01-01

The layout of the micropower 4-bit smoothing type buffer memory device allowing one to record without counting the sequence of input randomly distributed pulses in multi-channel devices with serial poll, is given. The power spent by a memory cell for one binary digit recording is not greater than 0.15 mW, the device dead time is 10 mus

Vegetative buffer strips for reducing herbicide transport in runoff: effects of buffer width, vegetation, and season

Science.gov (United States)

The effect of vegetative buffer strip (VBS) width, vegetation, and season of the year on herbicide transport in runoff has not been well documented for runoff prone soils. A multi-year replicated plot-scale study was conducted on an eroded claypan soil with the following objectives: 1) assess the ef...

Effect of buffer thickness on the retardation of radionuclide release from the high-level waste repository

International Nuclear Information System (INIS)

Cho, Won Jin; Lee, Jae Owan; Kang, Chul Hyung; Han, Kyung Won

2000-12-01

The radionuclide release from buffer in the high-level waste repository to the surrounding host rock was assessed, and the effect of the radial buffer thickness on the release rate was analyzed. The total release rates decrease sharply with increasing radial buffer thickness up to 0.25 m, and decrease moderately at the buffer thickness between 0.25 m and 0.5 m. But increasing the radial buffer thickness beyond 0.5 m has little effect in reducing radionuclide release. Therefore a radial buffer thickness between 0.25 m and 0.5 m is sufficient based on the viewpoint of radionuclide retention

A buffer bridge process for growing multiple YBa2Cu3O7-y grains from one top seed

International Nuclear Information System (INIS)

Lee, J-H; Park, S-D; Jun, B-H; Lee, J S; Kim, C-J; Han, S C; Han, Y H

2011-01-01

This study presents a buffer bridge process that allows growing multiple YBa 2 Cu 3 O 7-y (Y123) grains from one top seed. This process uses a buffer bridge pellet (Y 2 BaCuO 5 or Y123) to deliver the Y123 growth from one seed to several Y123 compacts. The top seeded melt growth (TSMG) process combined with the buffer bridge process facilitated the fabrication of several single-grained Y123 superconductors using one seed. In addition to achieving the growth of multiple Y123 grains, this process ensured a uniform distribution of superconducting properties of the top surface because the seed/compact interface area (the number of seeds), which is the route for the impurities from the seeds, was minimized. Additionally, the impurity contamination from a seed was considerably suppressed using a buffer pellet. One (110) diagonal facet line, as a result of the corner-to-corner growth, developed on the top surfaces of the prepared Y123 compacts, which is comparable to the x-like facet line of the conventional TSMG processed samples. The trapped magnetic field (H) profiles at 77 K of the prepared Y123 compacts, which were estimated using an Nd-B-Fe permanent magnet, showed the H contour map of a single-grain mode. The force-distance curves for the field cooled and zero-field cooled Y123 compacts at 77 K showed high and reliable levitation forces with a small deviation among compacts. The buffer bridge process can be applied to a batch process for the mass production of single-grain REBa 2 Cu 3 O 7-y (RE: rare-earth elements) superconductors with uniform top surface properties.

Study of buffer layer thickness on bulk heterojunction solar cell.

Science.gov (United States)

Noh, Seunguk; Suman, C K; Lee, Donggu; Kim, Seohee; Lee, Changhee

2010-10-01

We studied the effect of the buffer layer (molybdenum-oxide (MoO3)) thickness on the performance of organic solar cell based on blends of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61 butyric acid methyl ester fullerene derivative (PCBM). The thickness of MoO3 was varied from 1 nm to 30 nm for optimization of device performance. The photocurrent-voltage and impedance spectroscopy were measured under dark and AM1.5G solar simulated illumination of 100 mW/cm2 for exploring the role of the buffer layer thickness on carrier collection at an anode. The MoO3 thickness of the optimized device (efficiency approximately 3.7%) was found to be in the range of 5 approximately 10 nm. The short-circuit current and the shunt resistance decrease gradually for thicker MoO3 layer over 5 nm. The device can be modeled as the combination of three RC parallel circuits (each one for the active layer, buffer layer and interface between the buffer layer and the active layer) in series with contact resistance (Rs approximately 60 ohm).

EnviroAtlas - Paterson, NJ - 51m Riparian Buffer Vegetated Cover

Science.gov (United States)

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the riparian buffer is less vegetated. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the Atlas Area. EnviroAtlas defines vegetated buffer for this community as trees and forest and grass and herbaceous. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

Buffer layer investigations on MFIS capacitors consisting of ferroelectric poly[vinylidene fluoride trifluoroethylene

International Nuclear Information System (INIS)

Henkel, K; Seime, B; Paloumpa, I; Mueller, K; Schmeisser, D

2010-01-01

In this paper we present capacitance-voltage (CV) measurements on metal-ferroelectric-insulator-semiconductor (MFIS) capacitors with poly[vinylidene fluoride trifluoroethylene] (P[VDF/TrFE] as ferroelectric layer and SiO 2 , Al 2 O 3 and HfO 2 as buffering insulator layer. In order to discuss our data in a quantitative manner we perform fits to the data based on a model proposed by Miller and McWorther. The improvement of the polarization values and subsequently its effect on the hysteresis of the CV curve by the successive shrinking of the buffer layer thickness and the following choice of a high-k buffer material is demonstrated. Our data underline that a saturated polarization of P[VDF/TrFE] cannot be controlled with a SiO 2 buffer layer and the insertion of a high-k buffer layer is essential for further improvements of the characteristics of MFIS stacks.

Buffer substitution in malaria rapid diagnostic tests causes false-positive results

Directory of Open Access Journals (Sweden)

Van den Ende Jef

2010-07-01

Full Text Available Abstract Background Malaria rapid diagnostic tests (RDTs are kits that generally include 20 to 25 test strips or cassettes, but only a single buffer vial. In field settings, laboratory staff occasionally uses saline, distilled water (liquids for parenteral drugs dilution or tap water as substitutes for the RDT kit's buffer to compensate for the loss of a diluent bottle. The present study assessed the effect of buffer substitution on the RDT results. Methods Twenty-seven RDT brands were run with EDTA-blood samples of five malaria-free subjects, who were negative for rheumatoid factor and antinuclear antibodies. Saline, distilled water and tap water were used as substitute liquids. RDTs were also run with distilled water, without adding blood. Results were compared to those obtained with the RDT kit's buffer and Plasmodium positive samples. Results Only eight cassettes (in four RDT brands showed no control line and were considered invalid. Visible test lines occurred for at least one malaria-free sample and one of the substitutes in 20/27 (74% RDT brands (saline: n = 16; distilled water: n = 17; and tap water: n = 20, and in 15 RDTs which were run with distilled water only. They occurred for all Plasmodium antigens and RDT formats (two-, three- and four-band RDTs. Clearance of the background of the strip was excellent except for saline. The aspects (colour, intensity and crispness of the control and the false-positive test lines were similar to those obtained with the RDT kits' buffer and Plasmodium positive samples. Conclusion Replacement of the RDT kit's dedicated buffer by saline, distilled water and tap water can cause false-positive test results.

Safety of an alkalinizing buffer designed for inhaled medications in humans.

Science.gov (United States)

Davis, Michael D; Walsh, Brian K; Dwyer, Scott T; Combs, Casey; Vehse, Nico; Paget-Brown, Alix; Pajewski, Thomas; Hunt, John F

2013-07-01

Airway acidification plays a role in disorders of the pulmonary tract. We hypothesized that the inhalation of alkalinized glycine buffer would measurably alkalinize the airways without compromising lung function or causing adverse events. We evaluated the safety of an inhaled alkaline glycine buffer in both healthy subjects and in subjects with stable obstructive airway disease. This work includes 2 open-label safety studies. The healthy controls were part of a phase 1 safety study of multiple inhalations of low-dose alkaline glycine buffer; nebulized saline was used as a comparator in 8 of the healthy controls. Subsequently, a phase 2 study in subjects with stable obstructive airway disease was completed using a single nebulized higher-dose strategy of the alkaline inhalation. We studied 20 non-smoking adults (10 healthy controls and 10 subjects with obstructive airway disease), both at baseline and after inhalation of alkaline buffer. We used spirometry and vital signs as markers of clinical safety. We used changes in fraction of exhaled nitric oxide (NO) and exhaled breath condensate (EBC) pH as surrogate markers of airway pH modification. Alkaline glycine inhalation was tolerated by all subjects in both studies, with no adverse effects on spirometric parameters or vital signs. Airway alkalinization was confirmed by a median increase in EBC pH of 0.235 pH units (IQR 0.56-0.03, P = .03) in subjects after inhalation of the higher-dose alkaline buffer (2.5 mL of 100 mmol/L glycine). Alkalinization of airway lining fluid is accomplished with inhalation of alkaline glycine buffer and causes no adverse effects on pulmonary function or vital signs.

Implementing the countercyclical capital buffer in South Africa: Practical considerations

OpenAIRE

Pravin Burra; Pieter Juriaan de Jongh; Helgard Raubenheimer; Gary van Vuuren; Henco Wiid

2015-01-01

The Basel II regulatory framework significantly increased the resilience of the banking system, but proved ineffective in preventing the 2008/9 financial crisis. The subsequent introduction of Basel III aimed, inter alia, to supplement bank capital using buffers. The countercyclical buffer boosts existing minimum capital requirements when systemic risk surges are detected. Bolstering capital in favourable economic conditions cushions losses in unfavourable conditions, thereby addressing capit...

TRIS buffer in simulated body fluid distorts the assessment of glass-ceramic scaffold bioactivity.

Science.gov (United States)

Rohanová, Dana; Boccaccini, Aldo Roberto; Yunos, Darmawati Mohamad; Horkavcová, Diana; Březovská, Iva; Helebrant, Aleš

2011-06-01

The paper deals with the characterisation of the bioactive phenomena of glass-ceramic scaffold derived from Bioglass® (containing 77 wt.% of crystalline phases Na(2)O·2CaO·3SiO(2) and CaO·SiO(2) and 23 wt.% of residual glass phase) using simulated body fluid (SBF) buffered with tris-(hydroxymethyl) aminomethane (TRIS). A significant effect of the TRIS buffer on glass-ceramic scaffold dissolution in SBF was detected. To better understand the influence of the buffer, the glass-ceramic scaffold was exposed to a series of in vitro tests using different media as follows: (i) a fresh liquid flow of SBF containing tris (hydroxymethyl) aminomethane; (ii) SBF solution without TRIS buffer; (iii) TRIS buffer alone; and (iv) demineralised water. The in vitro tests were provided under static and dynamic arrangements. SBF buffered with TRIS dissolved both the crystalline and residual glass phases of the scaffold and a crystalline form of hydroxyapatite (HAp) developed on the scaffold surface. In contrast, when TRIS buffer was not present in the solutions only the residual glassy phase dissolved and an amorphous calcium phosphate (Ca-P) phase formed on the scaffold surface. It was confirmed that the TRIS buffer primarily dissolved the crystalline phase of the glass-ceramic, doubled the dissolving rate of the scaffold and moreover supported the formation of crystalline HAp. This significant effect of the buffer TRIS on bioactive glass-ceramic scaffold degradation in SBF has not been demonstrated previously and should be considered when analysing the results of SBF immersion bioactivity tests of such systems. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Setting priorities for research on pollution reduction functions of agricultural buffers

Science.gov (United States)

Michael G. Dosskey

2002-01-01

The success of buffer installation initiatives and programs to reduce nonpoint source pollution of streams on agricultural lands will depend the ability of local planners to locate and design buffers for specific circumstances with substantial and predictable results. Current predictive capabilities are inadequate, and major sources of uncertainty remain. An...

Where should buffers go? modeling riparian habitat connectivity in northeast Kansas

Science.gov (United States)

Gary Bentrup; Todd Kellerman

2004-01-01

Through many funding programs, riparian buffers are being created on agricultural lands to address significant water quality problems. Society and landowners are demanding many other environmental and social services (e.g., wildlife habitat and income diversification) from this practice. Resource planners therefore need to design riparian buffer systems in the right...

Isostatic compression of buffer blocks. Middle scale

International Nuclear Information System (INIS)

Ritola, J.; Pyy, E.

2012-01-01

Manufacturing of buffer components using isostatic compression method has been studied in small scale in 2008 (Laaksonen 2010). These tests included manufacturing of buffer blocks using different bentonite materials and different compression pressures. Isostatic mould technology was also tested, along with different methods to fill the mould, such as vibration and partial vacuum, as well as a stepwise compression of the blocks. The development of manufacturing techniques has continued with small-scale (30 %) blocks (diameter 600 mm) in 2009. This was done in a separate project: Isostatic compression, manufacturing and testing of small scale (D = 600 mm) buffer blocks. The research on the isostatic compression method continued in 2010 in a project aimed to test and examine the isostatic manufacturing process of buffer blocks at 70 % scale (block diameter 1200 to 1300 mm), and the aim was to continue in 2011 with full-scale blocks (diameter 1700 mm). A total of nine bentonite blocks were manufactured at 70 % scale, of which four were ring-shaped and the rest were cylindrical. It is currently not possible to manufacture full-scale blocks, because there is no sufficiently large isostatic press available. However, such a compression unit is expected to be possible to use in the near future. The test results of bentonite blocks, produced with an isostatic pressing method at different presses and at different sizes, suggest that the technical characteristics, for example bulk density and strength values, are somewhat independent of the size of the block, and that the blocks have fairly homogenous characteristics. Water content and compression pressure are the two most important properties determining the characteristics of the compressed blocks. By adjusting these two properties it is fairly easy to produce blocks at a desired density. The commonly used compression pressure in the manufacturing of bentonite blocks is 100 MPa, which compresses bentonite to approximately

Isostatic compression of buffer blocks. Middle scale

Energy Technology Data Exchange (ETDEWEB)

Ritola, J.; Pyy, E. [VTT Technical Research Centre of Finland, Espoo (Finland)

2012-01-15

Manufacturing of buffer components using isostatic compression method has been studied in small scale in 2008 (Laaksonen 2010). These tests included manufacturing of buffer blocks using different bentonite materials and different compression pressures. Isostatic mould technology was also tested, along with different methods to fill the mould, such as vibration and partial vacuum, as well as a stepwise compression of the blocks. The development of manufacturing techniques has continued with small-scale (30 %) blocks (diameter 600 mm) in 2009. This was done in a separate project: Isostatic compression, manufacturing and testing of small scale (D = 600 mm) buffer blocks. The research on the isostatic compression method continued in 2010 in a project aimed to test and examine the isostatic manufacturing process of buffer blocks at 70 % scale (block diameter 1200 to 1300 mm), and the aim was to continue in 2011 with full-scale blocks (diameter 1700 mm). A total of nine bentonite blocks were manufactured at 70 % scale, of which four were ring-shaped and the rest were cylindrical. It is currently not possible to manufacture full-scale blocks, because there is no sufficiently large isostatic press available. However, such a compression unit is expected to be possible to use in the near future. The test results of bentonite blocks, produced with an isostatic pressing method at different presses and at different sizes, suggest that the technical characteristics, for example bulk density and strength values, are somewhat independent of the size of the block, and that the blocks have fairly homogenous characteristics. Water content and compression pressure are the two most important properties determining the characteristics of the compressed blocks. By adjusting these two properties it is fairly easy to produce blocks at a desired density. The commonly used compression pressure in the manufacturing of bentonite blocks is 100 MPa, which compresses bentonite to approximately

Salivary buffer capacity, pH, and stimulated flow rate of crack cocaine users.

Science.gov (United States)

Woyceichoski, Iverson Ernani Cogo; Costa, Carlos Henrique; de Araújo, Cristiano Miranda; Brancher, João Armando; Resende, Luciane Grochocki; Vieira, Iran; de Lima, Antonio Adilson Soares

2013-08-01

Crack cocaine is the freebase form of cocaine that can be smoked. The use of this drug has been considered a public health problem in many countries. The aim of this study was to assess the stimulated salivary flow rate (SSFR), pH, and the buffer capacity of saliva in crack cocaine users. Stimulated whole saliva was collected from 54 selected crack cocaine users and 40 non-users. All samples were analyzed for SSFR, pH, and buffer capacity. SSFR was analyzed by gravimetric method. The buffer capacity and pH were determined using a digital pH meter. The crack cocaine users demonstrated higher buffer capacity than the control group (P > 0.05). Salivary pH was lower in crack cocaine users (P 0.05). Crack cocaine users might exhibit a significant decrease in salivary pH, but not in salivary flow rate or buffer capacity. © 2012 Blackwell Publishing Asia Pty Ltd.

A Novel Buffer Management Architecture for Epidemic Routing in Delay Tolerant Networks (DTNs)

KAUST Repository

Elwhishi, Ahmed; Ho, Pin-Han; Naik, K.; Shihada, Basem

2010-01-01

Delay tolerant networks (DTNs) are wireless networks in which an end-to-end path for a given node pair can never exist for an extended period. It has been reported as a viable approach in launching multiple message replicas in order to increase message delivery ratio and reduce message delivery delay. This advantage, nonetheless, is at the expense of taking more buffer space at each node. The combination of custody and replication entails high buffer and bandwidth overhead. This paper investigates a new buffer management architecture for epidemic routing in DTNs, which helps each node to make a decision on which message should be forwarded or dropped. The proposed buffer management architecture is characterized by a suite of novel functional modules, including Summary Vector Exchange Module (SVEM), Networks State Estimation Module (NSEM), and Utility Calculation Module (UCM). Extensive simulation results show that the proposed buffer management architecture can achieve superb performance against its counterparts in terms of delivery ratio and delivery delay.

A Novel Buffer Management Architecture for Epidemic Routing in Delay Tolerant Networks (DTNs)

KAUST Repository

Elwhishi, Ahmed

2010-11-17

Delay tolerant networks (DTNs) are wireless networks in which an end-to-end path for a given node pair can never exist for an extended period. It has been reported as a viable approach in launching multiple message replicas in order to increase message delivery ratio and reduce message delivery delay. This advantage, nonetheless, is at the expense of taking more buffer space at each node. The combination of custody and replication entails high buffer and bandwidth overhead. This paper investigates a new buffer management architecture for epidemic routing in DTNs, which helps each node to make a decision on which message should be forwarded or dropped. The proposed buffer management architecture is characterized by a suite of novel functional modules, including Summary Vector Exchange Module (SVEM), Networks State Estimation Module (NSEM), and Utility Calculation Module (UCM). Extensive simulation results show that the proposed buffer management architecture can achieve superb performance against its counterparts in terms of delivery ratio and delivery delay.

Numerical Study on the Effect of Buffer Bow Structure in Ship-to-ship Collisions

DEFF Research Database (Denmark)

Yamada, Yasuhira; Endo, Hisayoshi; Pedersen, Preben Terndrup

2005-01-01

tankers, the introduction of buffer bulbous bows has been proposed. Relatively soft buffer bows absorb part of the kinetic energy of the striking ship before penetrating the inner hull of the struck vessel. The purpose of the present paper is to verify the effectiveness of a prototype buffer bulbous bow......) and the forward velocity of the struck ship on the collapse mode of the bow of the striking vessel are investigated. Collapse modes, contact forces and energy absorption capabilities of the buffer bows are compared with those of conventional bows....

Magnetic two-dimensional electron gas at the manganite-buffered LaAlO3/SrTiO3 interface

DEFF Research Database (Denmark)

R. Zhang, H.; Zhang, Y.; Zhang, H.

2017-01-01

Fabrication of highly mobile spin-polarized two-dimensional electron gas (2DEG) is crucially important for both fundamental and applied research. Usually, spin polarization appears below 10 K for the 2DEG of LaAlO3/SrTiO3 interface, stemming from the magnetic ordering of Ti3+ ions with the mediat......Fabrication of highly mobile spin-polarized two-dimensional electron gas (2DEG) is crucially important for both fundamental and applied research. Usually, spin polarization appears below 10 K for the 2DEG of LaAlO3/SrTiO3 interface, stemming from the magnetic ordering of Ti3+ ions...... with the mediation of itinerant electrons. Herein, we report a magnetic 2DEG at a La7/8Sr1/8MnO3-buffered LaAlO3/SrTiO3 interface, which simultaneously shows electrically tunable anomalous Hall effect and high conductivity. The spin-polarized temperature for the 2DEG is promoted to 30 K while the mobility remains...... high. The magnetism likely results from a gradient manganese interdiffusion into SrTiO3. The present work demonstrates the great potential of manganite-buffered LaAlO3/SrTiO3 interfaces for spintronic applications....

Effects of logging on macroinvertebrates in streams with and without buffer strips

Energy Technology Data Exchange (ETDEWEB)

Newbold, J D; Erman, D C; Roby, K B

1980-01-01

The impact of logging with and without buffer strip protection on stream macroinvertebrates was examined through comparisons of community structure in commercially logged and control watersheds throughout northern California. A nonparametric test of community dissimilarities within matched blocks of two control and one or two treated stations showed significant (P < 0.05) logging effects on unprotected streams when Euclidean distance and mutual information were used as dissimilarity indices, but not when chord distance was used. Shannon diversity in unprotected streams was lower (P < 0.01) than in control (unlogged) streams; densities of total macroinvertebrate fauna and of Chironomidae, Baetis, and Nemoura were higher in unprotected streams than in controls (P <0.05). Streams with narrow buffer strips (<30 m) showed significant effects by the Euclidean distance test, but diversity varied widely and was not significantly different from that in either unprotected or control streams than in controls (P < 0.05). Macroinvertebrate communities in streams with wide buffers (greater than or equal to 30m) could not be distinguished from those of controls by either Euclidean distance or diversity; however, diversity in wide-buffered streams was significantly greater than in streams without buffer strips, indicating effective protection from logging effects.

An Experimental Test of Buffer Utility as a Technique for Managing Pool-Breeding Amphibians.

Science.gov (United States)

Powell, Jessica S Veysey; Babbitt, Kimberly J

2015-01-01

Vegetated buffers are used extensively to manage wetland-dependent wildlife. Despite widespread application, buffer utility has not been experimentally validated for most species. To address this gap, we conducted a six-year, landscape-scale experiment, testing how buffers of different widths affect the demographic structure of two amphibian species at 11 ephemeral pools in a working forest of the northeastern U.S. We randomly assigned each pool to one of three treatments (i.e., reference, 100m buffer, 30m buffer) and clearcut to create buffers. We captured all spotted salamanders and wood frogs breeding in each pool and examined the impacts of treatment and hydroperiod on breeding-population abundance, sex ratio, and recapture rate. The negative effects of clearcutting tended to increase as forest-buffer width decreased and be strongest for salamanders and when other stressors were present (e.g., at short-hydroperiod pools). Recapture rates were reduced in the 30m, but not 100m, treatment. Throughout the experiment for frogs, and during the first year post-cut for salamanders, the predicted mean proportion of recaptured adults in the 30m treatment was only 62% and 40%, respectively, of that in the reference treatment. Frog sex ratio and abundance did not differ across treatments, but salamander sex ratios were increasingly male-biased in both cut treatments. By the final year, there were on average, only about 40% and 65% as many females predicted in the 100m and 30m treatments, respectively, compared to the first year. Breeding salamanders at short-hydroperiod pools were about 10% as abundant in the 100m versus reference treatment. Our study demonstrates that buffers partially mitigate the impacts of habitat disturbance on wetland-dependent amphibians, but buffer width and hydroperiod critically mediate that process. We provide the first experimental evidence showing that 30-m-wide buffers may be insufficient for maintaining resilient breeding populations of pool

An Experimental Test of Buffer Utility as a Technique for Managing Pool-Breeding Amphibians.

Directory of Open Access Journals (Sweden)

Jessica S Veysey Powell

Full Text Available Vegetated buffers are used extensively to manage wetland-dependent wildlife. Despite widespread application, buffer utility has not been experimentally validated for most species. To address this gap, we conducted a six-year, landscape-scale experiment, testing how buffers of different widths affect the demographic structure of two amphibian species at 11 ephemeral pools in a working forest of the northeastern U.S. We randomly assigned each pool to one of three treatments (i.e., reference, 100m buffer, 30m buffer and clearcut to create buffers. We captured all spotted salamanders and wood frogs breeding in each pool and examined the impacts of treatment and hydroperiod on breeding-population abundance, sex ratio, and recapture rate. The negative effects of clearcutting tended to increase as forest-buffer width decreased and be strongest for salamanders and when other stressors were present (e.g., at short-hydroperiod pools. Recapture rates were reduced in the 30m, but not 100m, treatment. Throughout the experiment for frogs, and during the first year post-cut for salamanders, the predicted mean proportion of recaptured adults in the 30m treatment was only 62% and 40%, respectively, of that in the reference treatment. Frog sex ratio and abundance did not differ across treatments, but salamander sex ratios were increasingly male-biased in both cut treatments. By the final year, there were on average, only about 40% and 65% as many females predicted in the 100m and 30m treatments, respectively, compared to the first year. Breeding salamanders at short-hydroperiod pools were about 10% as abundant in the 100m versus reference treatment. Our study demonstrates that buffers partially mitigate the impacts of habitat disturbance on wetland-dependent amphibians, but buffer width and hydroperiod critically mediate that process. We provide the first experimental evidence showing that 30-m-wide buffers may be insufficient for maintaining resilient breeding

Effect of Tris-acetate buffer on endotoxin removal from human-like collagen used biomaterials

International Nuclear Information System (INIS)

Zhang, Huizhi; Fan, Daidi; Deng, Jianjun; Zhu, Chenghui; Hui, Junfeng; Ma, Xiaoxuan

2014-01-01

Protein preparation, which has active ingredients designated for the use of biomaterials and therapeutical protein, is obtained by genetic engineering, but products of genetic engineering are often contaminated by endotoxins. Because endotoxin is a ubiquitous and potent proinflammatory agent, endotoxin removal or depletion from protein is essential for researching any biomaterials. In this study, we have used Tris-acetate (TA) buffer of neutral pH value to evaluate endotoxins absorbed on the Pierce high-capacity endotoxin removal resin. The effects of TA buffer on pH, ionic strength, incubation time as well as human-like collagen (HLC) concentration on eliminating endotoxins are investigated. In the present experiments, we design an optimal method for TA buffer to remove endotoxin from recombinant collagen and use a chromogenic tachypleus amebocyte lysate (TAL) test kit to measure the endotoxin level of HLC. The present results show that, the endotoxins of HLC is dropped to 8.3 EU/ml at 25 mM TA buffer (pH 7.8) with 150 mM NaCl when setting incubation time at 6 h, and HLC recovery is about 96%. Under this experimental condition, it is proved to exhibit high efficiencies of both endotoxin removal and collagen recovery. The structure of treated HLC was explored by Transmission Electron Microscopy (TEM), demonstrating that the property and structure of HLC treated by TA buffer are maintained. Compared to the most widely used endotoxin removal method, Triton X-114 extraction, using TA buffer can obtain the non-toxic HLC without extra treatment for removing the toxic substances in Triton X-114. In addition, the present study aims at establishing a foundation for further work in laboratory animal science and providing a foundation for medical grade biomaterials. - Graphical abstract: The processes of endotoxins adsorbed from HLC. - Highlights: • TA buffer is a mild buffer system for endotoxins removal of HLC. • TA buffer may facilitate endotoxins adsorbed on the

Simulation of HTM processes in buffer-rock barriers based on the French HLW disposal concept

International Nuclear Information System (INIS)

Li, Xiaoshuo; Roehlig, Klaus-Juergen; Zhang, Chunliang

2012-01-01

Document available in extended abstract form only. The main objectives of this paper are to gain experience with modelling and analysis of HTM processes in clay rock and bentonite buffer surrounding heat-generating radioactive waste. The French concept for HLW disposal in drifts with backfilled bentonite buffer considered in numerical calculations which are carried out by using the computer code CODE-BRIGHT developed by the Technical University of Catalonia in Barcelona. The French repository designed by ANDRA is located in the middle of the Callovo-Oxfordian argillaceous formation (COX) of 250 m thickness at a depth of 500 to 630 m below the surface. The French concept has been simplified at this simulation work. A drift is considered to be excavated at a depth of 500 m below the surface. It has a diameter of 2.2 m and a length of 20 m. A large volume of the rock mass around the drift is taken into account by an axisymmetric model of 100 m radius and 100 m length. In fact, this model represents a cylindrical rock-buffer-system with the central axis of the containers, as shown in Figure 1. Some points are selected in the buffer and the rock along the radial line (dash yellow line) in the middle of the drift for recording HTM parameters with time. The display and analysis of the results at this paper are chiefly along this line. The simulation work has been divided to two time steps. At the first step, the drift excavation and ventilation is simulated by reducing the stress normal to the drift wall down to zero and circulating gas along the drift wall with relative humidity of 85 %. Following the drift excavation and ventilation, the HLW containers and the bentonite are emplaced in the drift as the second step of the simulation. This is simulated by simultaneously applying the initial conditions of the buffer and the decayed heat emitting from the waste containers as thermal boundary conditions. Two materials (Clay rock and bentonite buffer) are taken into account

Stability of buffer-free freeze-dried formulations: A feasibility study of a monoclonal antibody at high protein concentrations.

Science.gov (United States)

Garidel, Patrick; Pevestorf, Benjamin; Bahrenburg, Sven

2015-11-01

We studied the stability of freeze-dried therapeutic protein formulations over a range of initial concentrations (from 40 to 160 mg/mL) and employed a variety of formulation strategies (including buffer-free freeze dried formulations, or BF-FDF). Highly concentrated, buffer-free liquid formulations of therapeutic monoclonal antibodies (mAbs) have been shown to be a viable alternative to conventionally buffered preparations. We considered whether it is feasible to use the buffer-free strategy in freeze-dried formulations, as an answer to some of the known drawbacks of conventional buffers. We therefore conducted an accelerated stability study (24 weeks at 40 °C) to assess the feasibility of stabilizing freeze-dried formulations without "classical" buffer components. Factors monitored included pH stability, protein integrity, and protein aggregation. Because the protein solutions are inherently self-buffering, and the system's buffer capacity scales with protein concentration, we included highly concentrated buffer-free freeze-dried formulations in the study. The tested formulations ranged from "fully formulated" (containing both conventional buffer and disaccharide stabilizers) to "buffer-free" (including formulations with only disaccharide lyoprotectant stabilizers) to "excipient-free" (with neither added buffers nor stabilizers). We evaluated the impacts of varying concentrations, buffering schemes, pHs, and lyoprotectant additives. At the end of 24 weeks, no change in pH was observed in any of the buffer-free formulations. Unbuffered formulations were found to have shorter reconstitution times and lower opalescence than buffered formulations. Protein stability was assessed by visual inspection, sub-visible particle analysis, protein monomer content, charge variants analysis, and hydrophobic interaction chromatography. All of these measures found the stability of buffer-free formulations that included a disaccharide stabilizer comparable to buffer

Buffered or under Scrutiny?

DEFF Research Database (Denmark)

Klopf, Patricia; Nell, Phillip C.; Puck, Jonas

– they are to a stronger extent buffered from the external environment than small firms. Thus, this paper adds to previous research by disentangling the complex effects of size on the use of political strategies – a strand of literature which has been characterized by inconsistent findings in the past.......This paper investigates political strategies of MNE subsidiaries operating in emerging markets. Our findings support previous findings of more intense political strategies in the presence of stronger institutional pressures from public and private stakeholders. Furthermore, we hypothesize...

Phosphate and HEPES buffers potently affect the fibrillation and oligomerization mechanism of Alzheimer's Aβ peptide

International Nuclear Information System (INIS)

Garvey, Megan; Tepper, Katharina; Haupt, Caroline; Knuepfer, Uwe; Klement, Karolin; Meinhardt, Jessica; Horn, Uwe; Balbach, Jochen; Faendrich, Marcus

2011-01-01

Highlights: → Sodium phosphate buffer accelerated Aβ(1-40) nucleation relative to HEPES. → Aβ(1-40) fibrils formed in the two buffers show only minor structural differences. → NMR revealed that Aβ(1-40) histidine residues mediate buffer dependent changes. -- Abstract: The oligomerization of Aβ peptide into amyloid fibrils is a hallmark of Alzheimer's disease. Due to its biological relevance, phosphate is the most commonly used buffer system for studying the formation of Aβ and other amyloid fibrils. Investigation into the characteristics and formation of amyloid fibrils frequently relies upon material formed in vitro, predominantly in phosphate buffers. Herein, we examine the effects on the fibrillation and oligomerization mechanism of Aβ peptide that occur due solely to the influence of phosphate buffer. We reveal that significant differences in amyloid fibrillation are observed due to fibrillation being initiated in phosphate or HEPES buffer (at physiological pH and temperature). Except for the differing buffer ions, all experimental parameters were kept constant. Fibril formation was assessed using fluorescently monitored kinetic studies, microscopy, X-ray fiber diffraction and infrared and nuclear magnetic resonance spectroscopies. Based on this set up, we herein reveal profound effects on the mechanism and speed of Aβ fibrillation. The three histidine residues at positions 6, 13 and 14 of Aβ(1-40) are instrumental in these mechanistic changes. We conclude that buffer plays a more significant role in fibril formation than has been generally acknowledged.

Final Report: Rational Design of Wide Band Gap Buffer Layers for High-Efficiency Thin-Film Photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Lordi, Vincenzo [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-09-30

The main objective of this project is to enable rational design of wide band gap buffer layer materials for CIGS thin-film PV by building understanding of the correlation of atomic-scale defects in the buffer layer and at the buffer/absorber interface with device electrical properties. Optimized wide band gap buffers are needed to reduce efficiency loss from parasitic absorption in the buffer. The approach uses first-principles materials simulations coupled with nanoscale analytical electron microscopy as well as device electrical characterization. Materials and devices are produced by an industrial partner in a manufacturing line to maximize relevance, with the goal of enabling R&D of new buffer layer compositions or deposition processes to push device efficiencies above 21%. Cadmium sulfide (CdS) is the reference material for analysis, as the prototypical high-performing buffer material.