WorldWideScience

Sample records for buffers

  1. Buffer design 2012

    International Nuclear Information System (INIS)

    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.)

  2. 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 available processor cores compared to its sequential counterpart, thereby taking full advantage of multicore parallelism. The parallel buffer tree is a search tree data structure that supports the batched parallel processing of a sequence of N insertions, deletions, membership queries, and range queries...... 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....

  3. Buffer moisture protection system

    International Nuclear Information System (INIS)

    With the present knowledge, bentonite blocks have to be protected from the air relative humidity and from any moisture leakages in the environment that might cause swelling of the bentonite blocks during the 'open' installation phase before backfilling. The purpose of this work was to design the structural reference solution both for the bottom of the deposition hole and for the buffer moisture protection and dewatering system with their integrated equipment needed in the deposition hole. This report describes the Posiva's reference solution for the buffer moisture protection system and the bottom plate on basis of the demands and functional requirements set by long-term safety. The reference solution with structural details has been developed in research work made 2010-2011. The structural solution of the moisture protection system has not yet been tested in practice. On the bottom of the deposition hole a copper plate which protects the lowest bentonite block from the gathered water is installed straight to machined and even rock surface. The moisture protection sheet made of EPDM rubber is attached to the copper plate with an inflatable seal. The upper part of the moisture protection sheet is fixed to the collar structures of the lid which protects the deposition hole in the disposal tunnel. The main function of the moisture protection sheet is to protect bentonite blocks from the leaking water and from the influence of the air humidity at their installation stage. The leaking water is controlled by the dewatering and alarm system which has been integrated into the moisture protection liner. (orig.)

  4. Buffer moisture protection system

    Energy Technology Data Exchange (ETDEWEB)

    Ritola, J.; Peura, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2013-11-15

    With the present knowledge, bentonite blocks have to be protected from the air relative humidity and from any moisture leakages in the environment that might cause swelling of the bentonite blocks during the 'open' installation phase before backfilling. The purpose of this work was to design the structural reference solution both for the bottom of the deposition hole and for the buffer moisture protection and dewatering system with their integrated equipment needed in the deposition hole. This report describes the Posiva's reference solution for the buffer moisture protection system and the bottom plate on basis of the demands and functional requirements set by long-term safety. The reference solution with structural details has been developed in research work made 2010-2011. The structural solution of the moisture protection system has not yet been tested in practice. On the bottom of the deposition hole a copper plate which protects the lowest bentonite block from the gathered water is installed straight to machined and even rock surface. The moisture protection sheet made of EPDM rubber is attached to the copper plate with an inflatable seal. The upper part of the moisture protection sheet is fixed to the collar structures of the lid which protects the deposition hole in the disposal tunnel. The main function of the moisture protection sheet is to protect bentonite blocks from the leaking water and from the influence of the air humidity at their installation stage. The leaking water is controlled by the dewatering and alarm system which has been integrated into the moisture protection liner. (orig.)

  5. 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. PMID:23296746

  6. BUFFERS AND VEGETATIVE FILTER STRIPS

    Science.gov (United States)

    Buffers and filter strips are areas of permanent vegetation located within and between agricultural fields and the water courses to which they drain. These buffers are intended to intercept and slow runoff thereby providing water quality benefits. In addition, in many settings they are intended to...

  7. Heat conductivity of buffer materials

    International Nuclear Information System (INIS)

    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

  8. 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)

  9. 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....

  10. Buffering in cyclic gene networks

    Science.gov (United States)

    Glyzin, S. D.; Kolesov, A. Yu.; Rozov, N. Kh.

    2016-06-01

    We consider cyclic chains of unidirectionally coupled delay differential-difference equations that are mathematical models of artificial oscillating gene networks. We establish that the buffering phenomenon is realized in these system for an appropriate choice of the parameters: any given finite number of stable periodic motions of a special type, the so-called traveling waves, coexist.

  11. Dual mode logic buffers for VLSI interconnects

    Directory of Open Access Journals (Sweden)

    A.Ilakkiya

    2015-10-01

    Full Text Available Buffer insertion is a mechanism widely used to increase the performance of VLSI digital circuits. Buffer insertion has a strong impact on reliability in terms of delay and power dissipation of synchronous systems, since the clock distribution system requires reduced or controlled clock skew, being the buffer insertion and buffer sizing becomes an important aspect. Buffer insertion has also been used to reduce the noise generation, especially in heavy loaded nets, since the inclusion of buffer helps to desynchronize signal transitions.

  12. A Capital Adequacy Buffer Model

    OpenAIRE

    David Allen; Michael McAleer

    2013-01-01

    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 structural model which measures distance to default and the timeless capital asset pricing model (CAPM) which measures additional returns to compensate for additional share price risk.

  13. Static Switching Dynamic Buffer Circuit

    OpenAIRE

    Pandey, A. K.; R. A. Mishra; R. K. Nagaria

    2013-01-01

    We proposed footless domino logic buffer circuit. It minimizes redundant switching at the dynamic and the output nodes. The proposed circuit avoids propagation of precharge pulse to the output node and allows the dynamic node which saves power consumption. Simulation is done using 0.18 µm CMOS technology. We have calculated the power consumption, delay, and power delay product of the proposed circuit and compared the results with the existing circuits for different logic function, loading co...

  14. Buffer erosion in dilute groundwater

    International Nuclear Information System (INIS)

    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

  15. Buffer-aided multihop wireless communications

    OpenAIRE

    Dong, Chen

    2014-01-01

    In this thesis, we propose a suite of buffer-aided transmission schemes designed for a multihop link or for a three-node network by exploiting the characteristics of buffer-aided transmissions. Our objective is to improve the end-to-end BER, outage probability, throughput and energy dissipation. Specifically, we firstly proposed and studied a buffer-aided multihop link (MHL), where all the relay nodes (RNs) are assumed to have buffers for temporarily storing their received packets. Hence,...

  16. 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.

  17. BUFFER CAPACITY IN HETEROGENEOUS MULTICOMPONENT SYSTEMS. REVIEW

    OpenAIRE

    Oxana Spinu; Igor Povar

    2015-01-01

    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.

  18. 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.

  19. Downscaled tests on buffer behaviour

    International Nuclear Information System (INIS)

    Two types of tests, nicknamed X-Boy (bentonite sample diameter 350 mm, sample height 800 mm) and Transu (sample diameter 269 mm, sample height 800 mm), were performed to investigate the early saturation behavior of the buffer at mock-up scale using distinct point inflows at 0.1 L/min across a range of solution salinity from tap water to 35 g/L. Specifically, swelling pressure development, piping and erosion due to groundwater inflow and the extent of the homogenization process from the initial heterogeneous state (i.e., compacted blocks and either an empty or pellet-filled gap between the blocks and test device wall) were followed. For all test formats a set of consistent observations were made. No significant resistance to inlet water pressure was observed for any of the tests, due to developments occurring within the test cylinders, indicating that flow pathways through the buffer system remained open. Effluent solids concentrations above background levels were observed over the course of all of the tests indicating continuous erosion. Relatively low swelling pressures (both axial and radial) were observed during all of the tests. Non-uniform, radial swelling pressure development and saturation (from post-mortem sampling) were observed for all of the tests. (orig.)

  20. Downscaled tests on buffer behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Pintado, X.; Adesola, F.; Turtiainen, M. [B and Tech Oy, Helsinki (Finland)

    2013-10-15

    Two types of tests, nicknamed X-Boy (bentonite sample diameter 350 mm, sample height 800 mm) and Transu (sample diameter 269 mm, sample height 800 mm), were performed to investigate the early saturation behavior of the buffer at mock-up scale using distinct point inflows at 0.1 L/min across a range of solution salinity from tap water to 35 g/L. Specifically, swelling pressure development, piping and erosion due to groundwater inflow and the extent of the homogenization process from the initial heterogeneous state (i.e., compacted blocks and either an empty or pellet-filled gap between the blocks and test device wall) were followed. For all test formats a set of consistent observations were made. No significant resistance to inlet water pressure was observed for any of the tests, due to developments occurring within the test cylinders, indicating that flow pathways through the buffer system remained open. Effluent solids concentrations above background levels were observed over the course of all of the tests indicating continuous erosion. Relatively low swelling pressures (both axial and radial) were observed during all of the tests. Non-uniform, radial swelling pressure development and saturation (from post-mortem sampling) were observed for all of the tests. (orig.)

  1. Melatonin: Buffering the Immune System

    Directory of Open Access Journals (Sweden)

    Juan M. Guerrero

    2013-04-01

    Full Text Available Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed.

  2. Moisture Buffering in the Indoor Environment

    OpenAIRE

    Svennberg, Kaisa

    2006-01-01

    Moisture buffering in the indoor environment is the ability, through absorption and desorption, of surface materials to attenuate the moisture variations of the indoor air. Moisture buffering plays an important role in understanding the risks for biological growth in surface materials in the indoor environment, e.g., mold growth on walls and house dust mites in beds, and thereby also have an impact on the health of the inhabitants. Apart from the health aspects, moisture buffering is also imp...

  3. 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

  4. Comparison of three buffers used in the formulation of buffered charcoal yeast extract medium.

    OpenAIRE

    Edelstein, P H; Edelstein, M A

    1993-01-01

    Growth of Legionella spp. on buffered charcoal yeast extract medium supplemented with alpha-ketoglutarate and formulated with 3-(n-morpholino)propanesulfonic acid (MOPS), 3-(n-morpholino)-2-hydroxypropanesulfonic acid (MOPSO), or n-(2-acetamido)-2-aminoethanesulfonic acid (ACES) buffer was similar. With three exceptions, growth was no different in buffered yeast extract broth supplemented with alpha-ketoglutarate and formulated with MOPS or ACES buffer.

  5. 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...

  6. 46 CFR 58.25-45 - Buffers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  7. African American College Women's Suicide Buffers.

    Science.gov (United States)

    Marion, Michelle S.; Range, Lillian M.

    2003-01-01

    To examine the relationships buffers may have with suicide ideation, 300 African American female college students completed measures of suicide ideation and buffers. Three variables accounted for a significant and unique portion of the variance in suicide ideation: family support, a view that suicide is unacceptable, and a collaborative religious…

  8. Shock buffer for nuclear control assembly

    International Nuclear Information System (INIS)

    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

  9. 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.

  10. Temperature buffer test. Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-04-15

    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 Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report is the final report and a summary of all work performed within the TBT project. The design and the installation of the different components are summarized: the depositions hole, the heating system, the bentonite blocks with emphasis on the initial density and water content in these, the filling of slots with sand or pellets, the retaining construction with the plug, lid and nine anchor cables, the artificial saturation system, and finally the instrumentation. An overview of the operational conditions is presented: the power output from heaters, which was 1,500 W (and also 1,600 W) from each heater during the first {approx}1,700 days, and then changed to 1,000 and 2,000 W, for the upper and lower heater respectively, during the last {approx}600 days. From the start, the bentonite was hydrated with a groundwater from a nearby bore-hole, but this groundwater was replaced with de-ionized water from day {approx}1,500, due to the high flow resistance of the injections points in the filter, which implied that a high filter pressure couldn't be sustained. The sand shield around the upper heater was hydrated from day {approx}1,500 to day {approx}1

  11. Temperature buffer test. Final report

    International Nuclear Information System (INIS)

    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 Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report is the final report and a summary of all work performed within the TBT project. The design and the installation of the different components are summarized: the depositions hole, the heating system, the bentonite blocks with emphasis on the initial density and water content in these, the filling of slots with sand or pellets, the retaining construction with the plug, lid and nine anchor cables, the artificial saturation system, and finally the instrumentation. An overview of the operational conditions is presented: the power output from heaters, which was 1,500 W (and also 1,600 W) from each heater during the first ∼1,700 days, and then changed to 1,000 and 2,000 W, for the upper and lower heater respectively, during the last ∼600 days. From the start, the bentonite was hydrated with a groundwater from a nearby bore-hole, but this groundwater was replaced with de-ionized water from day ∼1,500, due to the high flow resistance of the injections points in the filter, which implied that a high filter pressure couldn't be sustained. The sand shield around the upper heater was hydrated from day ∼1,500 to day ∼1,800. The sensors data concerning

  12. Electrophoretic mobilities of erythrocytes in various buffers

    Science.gov (United States)

    Plank, L. D.; Kunze, M. E.; Todd, P. W.

    1985-01-01

    The calibration of space flight equipment depends on a source of standard test particles, this test particle of choice is the fixed erythrocyte. Erythrocytes from different species have different electrophoretic mobilities. Electrophoretic mobility depends upon zeta potential, which, in turn depends upon ionic strength. Zeta potential decreases with increasing ionic strength, so cells have high electrophoretic mobility in space electrophoresis buffers than in typical physiological buffers. The electrophoretic mobilities of fixed human, rat, and rabbit erythrocytes in 0.145 M salt and buffers of varying ionic strength, temperature, and composition, to assess the effects of some of the unique combinations used in space buffers were characterized. Several effects were assessed: glycerol or DMSO (dimethylsulfoxide) were considered for use as cryoprotectants. The effect of these substances on erythrocyte electrophoretic mobility was examined. The choice of buffer depended upon cell mobility. Primary experiments with kidney cells established the choice of buffer and cryoprotectant. A nonstandard temperature of EPM in the suitable buffer was determined. A loss of ionic strength control occurs in the course of preparing columns for flight, the effects of small increases in ionic strength over the expected low values need to be evaluated.

  13. Buffer protection in the installation phase

    International Nuclear Information System (INIS)

    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

  14. 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....

  15. 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 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...... 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....

  16. Study on buffering characteristics of hydraulic absorber

    International Nuclear Information System (INIS)

    Control rod hydraulic drive mechanism (CRHDM) is a new type of in-vessel control rod drive technology. Hydraulic absorber is one of the key parts of control rod hydraulic drive line. It is used to buffer control rod when the rod scrams to prevent the cross-blades of control rod from deformation and damage. Based on the working process of the hydraulic absorber, a theoretical model of the buffering process was established. Calculation results of the theoretical model agree well with the experiment results. The trend of pressure change in absorber cylinder, the displacement and velocity of the piston and buffering force during the buffering process were obtained from the calculation results of the theoretical model. Then influence parameters about cushioning characteristics were analyzed, which laid foundation for optimal design of the hydraulic absorber. (authors)

  17. Marriage a Buffer Against Drinking Problems?

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_158887.html Marriage a Buffer Against Drinking Problems? Study found protective ... aware of the potentially important protective effects of marriage on alcohol problems, our study puts this observation ...

  18. ARC Filters with Diamond Transistors and Buffers

    OpenAIRE

    T. Dostal

    1998-01-01

    Active RC first and second order filters using diamond transistors (voltage controlled current sources) and voltage diamond buffers (voltage controlled voltage sources) are given in this paper. Circuits are simulated and experimentally compared.

  19. How Might New Neurons Buffer Against Stress?

    Science.gov (United States)

    ... 99 items) How Might New Neurons Buffer Against Stress? Clues Emerging from Studies in New Porter Neuroscience ... role in the action of antidepressants , resilience to stress , the benefits of exercise and enriched environments , and ...

  20. Moisture buffer capacity of different insulation materials

    DEFF Research Database (Denmark)

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

    2004-01-01

    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...... to the used analysis method and therefore great care has to be taken when comparing results of different experiments. This paper discusses this issue and will come with a recommendation of a simple and consistent way to present the moisture buffer capacity of the materials in contact with the indoor air...

  1. Buffer layer for thin film structures

    Energy Technology Data Exchange (ETDEWEB)

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2010-06-15

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  2. Buffer layer for thin film structures

    Energy Technology Data Exchange (ETDEWEB)

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2006-10-31

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  3. Lucas Heights buffer zone: plan of management

    International Nuclear Information System (INIS)

    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

  4. The Determinants of Capital Buffers in CEECs

    OpenAIRE

    D'Arack, Francesco; Levasseur, Sandrine

    2007-01-01

    Banking capital ratios show a steadily decline in almost Central and Eastern European Countries (CEECs) since 2001, despite unchanged capital adequacy rules. Using a dynamic panel-analysis based on country-level data for CEECs, we empirically assess the determinants of capital buffers. Main results are as follows. First, there are large and significant adjustment costs in raising capital. Second, banks behave pro-cyclically, depleting their buffers in upturns to benefit from unanticipated inv...

  5. Required buffer capacities in assembly systems

    Directory of Open Access Journals (Sweden)

    D. Krenczyk

    2007-07-01

    Full Text Available Purpose: The aim of the realised analysis is the determination of the set of conditions. The fulfilment of those conditions enables the synchronisation of the assembly system work into the steady state. It is necessary to specify the rules controlling the assembly system work. Rhythmic concurrent production with wide assortment in the considered assembly system is realised.Design/methodology/approach: The theoretical roots of the considerations presented in that paper include theory of constraints. The presented approach is consistent with the authority method called Requirements and Possibilities Balance Method (RPBMFindings: Two kinds of system buffers: the entrance buffers and the inter-resources buffers are considered in that paper. The number of buffers elements needed for production during first steady state of the given system has been determined. Mathematical formulas specifying the minimal capacity of the buffers allocated in the assembly system have been outworked.Research limitations/implications: The formulas specifying the minimal buffer capacity constitute the first step towards formulation of the automatic method. That method is designed for the automatic construction of rules controlling the system work during transient phases between two different steady states. The process enables automation of the introduction filling of the system buffers.Practical implications: The presented formulas can become an integrated part of existing authority software. The developed computer system aids the decision-making process connected with production planning and ensures effective utilisation of production resources. Moreover, the formulas correctness during computer simulations has been verified.Originality/value: To develop the formulas specifying the minimal capacity of the system buffers is the main achievement of the given paper. The presented approach permits to solve the problem concerning the synchronisation of the assembly system work

  6. Buffer regulation of calcium puff sequences

    International Nuclear Information System (INIS)

    Puffs are localized Ca2+ signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP3). They are the result of the liberation of Ca2+ from the endoplasmic reticulum through the coordinated opening of IP3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca2+ 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 Ca2+ signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP3R-Ca2+ 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 Ca2+ buffer can increase the average number of channels that participate of a puff. (paper)

  7. Buffer material applying method and device

    International Nuclear Information System (INIS)

    A powdery buffer material which can be solidified under pressure is charged into a disposing hole, an expandable/shrinkable hydraulic bag is inserted to the powdery buffer material, and then highly pressurized water is injected to expand the hydraulic bag and the powdery buffer material is urged to the inner wall surface of the disposing hole by expansion pressure to solidify and form a solid buffer material. Namely, a movable truck main body comprises a means for elevating an elevating plate so as to open/close an opening, an expandable/shrinkable hydraulic bag disposed to the lower surface of the elevating plate and a highly pressurized water-injection means for injecting highly pressurized water into the hydraulic bag. The buffer material is thus manufactured and applied simultaneously by transporting the heavy weighted buffer material in the form of a powder to a site and press-molding it in the disposing hole thereby capable of reducing the time, labor and cost required for transporting operation remarkably. (N.H.)

  8. 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.

  9. Static mechanical properties of buffer material

    International Nuclear Information System (INIS)

    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)

  10. Undergraduate Chemistry Students' Perceptions of and Misconceptions about Buffers and Buffer Problems

    Science.gov (United States)

    Orgill, MaryKay; Sutherland, Aynsley

    2008-01-01

    Both upper- and lower-level chemistry students struggle with understanding the concept of buffers and with solving corresponding buffer problems. While it might be reasonable to expect general chemistry students to struggle with this abstract concept, it is surprising that upper-level students in analytical chemistry and biochemistry continue to…

  11. Buffer construction technique using granular bentonite

    International Nuclear Information System (INIS)

    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/m3, 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)

  12. Buffer Overflow Detection on Binary Code

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yan-fei; LI Hui; CHEN Ke-fei

    2006-01-01

    Most solutions for detecting buffer overflow are based on source code. But the requirement for source code is not always practical especially for business software. A new approach was presented to detect statically the potential buffer overflow vulnerabilities in the binary code of software. The binary code was translated into assembly code without the lose of the information of string operation functions. The feature code abstract graph was constructed to generate more accurate constraint statements, and analyze the assembly code using the method of integer range constraint. After getting the elementary report on suspicious code where buffer overflows possibly happen, the control flow sensitive analysis using program dependence graph was done to decrease the rate of false positive. A prototype was implemented which demonstrates the feasibility and efficiency of the new approach.

  13. Buffer management optimization strategy for satellite ATM

    Institute of Scientific and Technical Information of China (English)

    Lu Rong; Cao Zhigang

    2006-01-01

    ECTD (erroneous cell tail drop), a buffer management optimization strategy is suggested which can improve the utilization of buffer resources in satellite ATM (asynchronous transfer mode) networks. The strategy, in which erroneous cells caused by satellite channel and the following cells that belong to the same PDU (protocol data Unit) are discarded, concerns non-real-time data services that use higher layer protocol for retransmission. Based on EPD (early packet drop) policy, mathematical models are established with and without ECTD. The numerical results show that ECTD would optimize buffer management and improve effective throughput (goodput), and the increment of goodput is relative to the CER (cell error ratio) and the PDU length. The higher their values are, the greater the increment. For example,when the average PDU length values are 30 and 90, the improvement of goodput are respectively about 4% and 10%.

  14. The buffer effect in neutral electrolyte supercapacitors

    DEFF Research Database (Denmark)

    Thrane Vindt, Steffen; Skou, Eivind M.

    2016-01-01

    The observation that double-layer capacitors based on neutral aqueous electrolytes can have significantly wider usable potential windows than those based on acidic or alkaline electrolytes is studied. This effect is explained by a local pH change taking place at the electrode surfaces, leading to a...... of addition of a buffer to such systems. It is shown that a 56 % higher dynamic storage capacity may be achieved, simply by controlling the buffer capacity of the electrolyte. The model system used, is based on a well-known commercial activated carbon (NORIT™ A SUPRA) as the electrode material...

  15. Buffer of Events as a Markovian Process

    International Nuclear Information System (INIS)

    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)

  16. Emplacement of small and large buffer blocks

    International Nuclear Information System (INIS)

    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

  17. On the Complexity of Buffer Allocation in Message Passing Systems

    OpenAIRE

    Brodsky, Alex; Pedersen, Jan B.; Wagner, Alan

    2003-01-01

    Message passing programs commonly use buffers to avoid unnecessary synchronizations and to improve performance by overlapping communication with computation. Unfortunately, using buffers makes the program no longer portable, potentially unable to complete on systems without a sufficient number of buffers. Effective buffer use entails that the minimum number needed for a safe execution be allocated. We explore a variety of problems related to buffer allocation for safe and efficient execution ...

  18. The buffer effect in neutral electrolyte supercapacitors

    Science.gov (United States)

    Vindt, Steffen T.; Skou, Eivind M.

    2016-02-01

    The observation that double-layer capacitors based on neutral aqueous electrolytes can have significantly wider usable potential windows than those based on acidic or alkaline electrolytes is studied. This effect is explained by a local pH change taking place at the electrode surfaces, leading to a change in the redox potential of water in opposite directions on the two electrodes, resulting in the wider stability window. The magnitude of this effect is suggested to be dependent on the buffer capacity, rather than the intrinsic pH value of the electrolyte. This is confirmed by studying the impact of addition of a buffer to such systems. It is shown that a 56 % higher dynamic storage capacity may be achieved, simply by controlling the buffer capacity of the electrolyte. The model system used, is based on a well-known commercial activated carbon (NORIT™ A SUPRA) as the electrode material, aqueous potassium nitrate as the electrolyte and potassium phosphates as the buffer system.

  19. A Discovery Chemistry Experiment on Buffers

    Science.gov (United States)

    Kulevich, Suzanne E.; Herrick, Richard S.; Mills, Kenneth V.

    2014-01-01

    The Holy Cross Chemistry Department has designed and implemented an experiment on buffers as part of our Discovery Chemistry curriculum. The pedagogical philosophy of Discovery Chemistry is to make the laboratory the focal point of learning for students in their first two years of undergraduate instruction. We first pose questions in prelaboratory…

  20. Buffer gas cooling of ion beams

    International Nuclear Information System (INIS)

    The cooling action of a buffer gas on ions contained within it can be used to cool an ion beam, thereby greatly improving its emittance and energy spread. It can also be used to greatly enhance the collection of an ion beam in an electromagnetic trap. The basic principles will be introduced in the context of a prototype system for such a beam cooler

  1. Analysis and Study of Buffer Overflow

    Institute of Scientific and Technical Information of China (English)

    Liu Sidong; Zen TaoYu; Yongquan

    2009-01-01

    Buffer overflow attack is one of the most threatening attack types and it jeopardizes security a lot. According to the principle of the attack, this paper demonstrates how it works, and emphasizes the importance of writing code that does not permit such attacks.

  2. Regulatory fit buffers against disidentification from groups

    NARCIS (Netherlands)

    Hamstra, Melvyn R.W.; Sassenberg, Kai; Van Yperen, Nico W.; Wisse, Barbara; Rietzschel, Eric F.

    2015-01-01

    Disidentification refers to people’s active psychological distancing from a group due to a negative self-defining affiliation with the group. Because disidentification can threaten group survival and group functioning, it is important to gain insight into factors that potentially buffer its occurren

  3. Reactive-Transport Model of Buffer Cementation

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Randy; Wei Zhou [Monitor Scientific LLC, Denver, CO (United States)

    2005-10-15

    Thermal gradients during the early, non-isothermal period of near-field evolution in a KBS-3 repository for spent nuclear fuel could alter the mineralogy of the bentonite buffer and cause the constituent clay particles to become cemented together by mineral precipitates. Cementation is a potential concern because it could alter the ductility, mechanical strength and swelling pressure of the buffer, thereby possibly adversely affecting the primary performance function of this key barrier to provide a stable diffusional transport pathway between the canister and rock. The present study uses the TOUGHREACT computer program to simulate reactive-transport processes that are thought to control buffer cementation. TOUGHREACT is generally applicable to problems involving non-isothermal, multiphase reactive transport in variably saturated media. For cementation problems, the modeling approach must account specifically for the temperature dependence of equilibrium and kinetic constraints on dissolution/precipitation reactions involving the primary smectite clays and accessory phases in bentonite, and for diffusive transport of aqueous reactants and products along concentration gradients that are aligned with, or in opposition to, the direction of decreasing temperatures across the near field. The modeling approach was evaluated in two stages. A conceptual model of buffer cementation was first calibrated using observations from field tests carried out at the Stripa mine and Aespoe HRL (LOT pilot experiments). The calibrated model was then used to simulate the geochemical evolution of the KBS-3 buffer during the non-isothermal period of repository evolution. This model accounts for the imbibition of groundwater from a granitic host rock into initially unsaturated buffer materials under capillary and hydraulic pressure gradients, and uses realistic time-temperature constraints on the thermal evolution of the near-field. Preliminary results suggest that the total extent of

  4. Reactive-Transport Model of Buffer Cementation

    International Nuclear Information System (INIS)

    Thermal gradients during the early, non-isothermal period of near-field evolution in a KBS-3 repository for spent nuclear fuel could alter the mineralogy of the bentonite buffer and cause the constituent clay particles to become cemented together by mineral precipitates. Cementation is a potential concern because it could alter the ductility, mechanical strength and swelling pressure of the buffer, thereby possibly adversely affecting the primary performance function of this key barrier to provide a stable diffusional transport pathway between the canister and rock. The present study uses the TOUGHREACT computer program to simulate reactive-transport processes that are thought to control buffer cementation. TOUGHREACT is generally applicable to problems involving non-isothermal, multiphase reactive transport in variably saturated media. For cementation problems, the modeling approach must account specifically for the temperature dependence of equilibrium and kinetic constraints on dissolution/precipitation reactions involving the primary smectite clays and accessory phases in bentonite, and for diffusive transport of aqueous reactants and products along concentration gradients that are aligned with, or in opposition to, the direction of decreasing temperatures across the near field. The modeling approach was evaluated in two stages. A conceptual model of buffer cementation was first calibrated using observations from field tests carried out at the Stripa mine and Aespoe HRL (LOT pilot experiments). The calibrated model was then used to simulate the geochemical evolution of the KBS-3 buffer during the non-isothermal period of repository evolution. This model accounts for the imbibition of groundwater from a granitic host rock into initially unsaturated buffer materials under capillary and hydraulic pressure gradients, and uses realistic time-temperature constraints on the thermal evolution of the near-field. Preliminary results suggest that the total extent of

  5. Power-Gating Technique for Network-on-Chip Buffers

    OpenAIRE

    Zamboni, Maurizio; Yadav, Manoj Kumar; Casu, Mario Roberto

    2013-01-01

    A new approach to reducing leakage power in network-on-chip buffers is presented. The non-uniformity of buffer utilisation is leveraged across the network and power-gating is applied to scarcely utilised buffers. Instead of turning-off the buffers completely, a buffer portion is kept turned-on. This design choice has a significant performance benefit because the buffer is always able to receive network packets. Design aspects and trade-offs in a 45 nm CMOS technology are discussed and results...

  6. Synthesis of Gold Nanoparticles with Buffer-Dependent Variations of Size and Morphology in Biological Buffers

    Science.gov (United States)

    Ahmed, Syed Rahin; Oh, Sangjin; Baba, Rina; Zhou, Hongjian; Hwang, Sungu; Lee, Jaebeom; Park, Enoch Y.

    2016-02-01

    The demand for biologically compatible and stable noble metal nanoparticles (NPs) has increased in recent years due to their inert nature and unique optical properties. In this article, we present 11 different synthetic methods for obtaining gold nanoparticles (Au NPs) through the use of common biological buffers. The results demonstrate that the sizes, shapes, and monodispersity of the NPs could be varied depending on the type of buffer used, as these buffers acted as both a reducing agent and a stabilizer in each synthesis. Theoretical simulations and electrochemical experiments were performed to understand the buffer-dependent variations of size and morphology exhibited by these Au NPs, which revealed that surface interactions and the electrostatic energy on the (111) surface of Au were the determining factors. The long-term stability of the synthesized NPs in buffer solution was also investigated. Most NPs synthesized using buffers showed a uniquely wide range of pH stability and excellent cell viability without the need for further modifications.

  7. Synthesis of Gold Nanoparticles with Buffer-Dependent Variations of Size and Morphology in Biological Buffers.

    Science.gov (United States)

    Ahmed, Syed Rahin; Oh, Sangjin; Baba, Rina; Zhou, Hongjian; Hwang, Sungu; Lee, Jaebeom; Park, Enoch Y

    2016-12-01

    The demand for biologically compatible and stable noble metal nanoparticles (NPs) has increased in recent years due to their inert nature and unique optical properties. In this article, we present 11 different synthetic methods for obtaining gold nanoparticles (Au NPs) through the use of common biological buffers. The results demonstrate that the sizes, shapes, and monodispersity of the NPs could be varied depending on the type of buffer used, as these buffers acted as both a reducing agent and a stabilizer in each synthesis. Theoretical simulations and electrochemical experiments were performed to understand the buffer-dependent variations of size and morphology exhibited by these Au NPs, which revealed that surface interactions and the electrostatic energy on the (111) surface of Au were the determining factors. The long-term stability of the synthesized NPs in buffer solution was also investigated. Most NPs synthesized using buffers showed a uniquely wide range of pH stability and excellent cell viability without the need for further modifications. PMID:26847691

  8. 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

  9. Isostatic compression of buffer blocks. Middle scale

    International Nuclear Information System (INIS)

    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

  10. 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.)

  11. Social buffering: relief from stress and anxiety

    OpenAIRE

    Kikusui, Takefumi; Winslow, James T.; Mori, Yuji

    2006-01-01

    Communication is essential to members of a society not only for the expression of personal information, but also for the protection from environmental threats. Highly social mammals have a distinct characteristic: when conspecific animals are together, they show a better recovery from experiences of distress. This phenomenon, termed ‘social buffering’, has been found in rodents, birds, non-human primates and also in humans. This paper reviews classical findings on social buffering and focuses...

  12. Microbial activity in bentonite buffers. Literature study

    International Nuclear Information System (INIS)

    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.)

  13. Bus Implementation Using New Low Power PFSCL Tristate Buffers

    OpenAIRE

    Neeta Pandey; Bharat Choudhary; Kirti Gupta; Ankit Mittal

    2016-01-01

    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 id...

  14. Exchangeability of bentonite buffer and backfill materials

    International Nuclear Information System (INIS)

    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

  15. Patterns of sediment and phosphorus accumulation in a riparian buffer

    Science.gov (United States)

    Riparian buffers prevent sediment and phosphorus (P) from reaching streams, but their accumulation in buffers is seldom measured. This study's objectives were to determine accumulations of sediment and P in a multi-species riparian buffer, and characterize spatial-temporal patterns of P in soil wate...

  16. Analysis of diffusive mass transport in a cracked buffer

    International Nuclear Information System (INIS)

    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/Deff, where D and Deff are the pore-water and the effective buffer diffusion coefficient, respectively. However, although a decrease in Deff 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 Deff value). Finally, for semi-impermeable boundary conditions, the effect of cracks on the total radionuclide flux is relatively small

  17. 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.

  18. Clad buffer rod sensors for liquid metals

    International Nuclear Information System (INIS)

    Clad buffer rods, consisting of a core and a cladding, have been developed for ultrasonic monitoring of liquid metal processing. The cores of these rods are made of low ultrasonic-loss materials and the claddings are fabricated by thermal spray techniques. The clad geometry ensures proper ultrasonic guidance. The lengths of these rods ranges from tens of centimeters to 1m. On-line ultrasonic level measurements in liquid metals such as magnesium at 700 deg C and aluminum at 960 deg C are presented to demonstrate their operation at high temperature and their high ultrasonic performance. A spherical concave lens is machined at the rod end for improving the spatial resolution. High quality ultrasonic images have been obtained in the liquid zinc at 600 deg C. High spatial resolution is needed for the detection of inclusions in liquid metals during processing. We also show that the elastic properties such as density, longitudinal and shear wave velocities of liquid metals can be measured using a transducer which generates and receives both longitudinal and shear waves and is mounted at the end of a clad buffer rod. (author)

  19. Competitive Buffer Management with Class Segregation

    CERN Document Server

    Al-Bawani, Kamal

    2011-01-01

    We introduce a new model for buffer management of network switches with Quality of Service (QoS) requirements and give a tight analysis. Specifically, each network packet is associated with a numerical value, called Class of Service (CoS), which represents its priority. We are furthermore given a network switch with $m$ queues that have individual capacities. Each queue stores packets of a certain CoS, only. A stream of packets arrives over time at the switch and an online algorithm has to decide on the admission and transmission of packets. The objective is to maximize the total CoS-value of the transmitted packets. Our main contribution is a natural online $\\GREEDY$ algorithm, which accepts any arriving packet, if the corresponding CoS-queue is not full. It always sends a buffered packet with highest value. We show that this algorithm is 2-competitive. This result is essentially best-possible since we also show a lower bound of $2 - v_m / (\\sum_{i=1}^m v_i)$ on the competitiveness of any deterministic onlin...

  20. Modelling the in situ performance of bentonite-sand buffer

    International Nuclear Information System (INIS)

    In the Canadian nuclear fuel waste management concept, a number of engineered barriers, such as the bentonite-sand buffer which surrounds the waste container in the emplacement boreholes, are used to inhibit the transport of radionuclides. The buffer material is also required to effectively conduct heat from the fuel-waste containers to the surrounding rock. To a large extent, in situ buffer performance will depend on the degree of moisture within the buffer. The moisture content will in turn depend on temperature, temperature gradients, and buffer initial and moisture flux boundary conditions. Modelling of coupled heat and moisture transport in the buffer before resaturation is necessary to assess in situ buffer performance. This paper describes the results of a parametric study using the Philip and de Vries coupled heat and moisture transport model to assess the effects of variations in the moisture diffusivity parameters and the boundary conditions on buffer performance. The results show that the thermal performance of the buffer is affected by heat-induced moisture movement. In particular, the thermal vapor diffusivity, DTvap, has the most significant effect on thermal drying in a closed system. Work is currently underway to improve capability to model coupled heat and moisture transport in buffer. Laboratory experiments are in progress to more accurately define the moisture diffusivity parameters and the model is being modified to include the effects of boundary moisture fluxes and pressure potentials so that the resaturation process may be modelled

  1. 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.

  2. Microscopic optical buffering in a harmonic potential

    CERN Document Server

    Sumetsky, M

    2015-01-01

    In the early days of quantum mechanics, Schr\\"odinger noticed that oscillations of a wave packet in a one-dimensional harmonic potential well are periodic and, in contrast to those in anharmonic potential wells, do not experience distortion over time. This original idea did not find applications up to now since an exact one-dimensional harmonic resonator does not exist in nature and has not been created artificially. However, an optical pulse propagating in a bottle microresonator (a dielectric cylinder with a nanoscale-high bump of the effective radius) can exactly imitate a quantum wave packet in the harmonic potential. Here, we propose a tuneable microresonator that can trap an optical pulse completely, hold it as long as the material losses permit, and release it without distortion. This result suggests the solution of the long standing problem of creating a microscopic optical buffer, the key element of the future optical signal processing devices.

  3. Liquid growth hormone: preservatives and buffers

    DEFF Research Database (Denmark)

    Kappelgaard, Anne-Marie; Anders, Bojesen; Skydsgaard, Karen; Sjögren, I; Laursen, Torben

    Abstract Growth hormone (GH) treatment is a successful medical therapy for children and adults with GH deficiency as well as for growth retardation due to chronic renal disease, Turner syndrome and in children born small for gestational age. For all of these conditions, treatment is long term and...... patients receive daily subcutaneous injections of GH for many years. Patient compliance is therefore of critical importance to ensure treatment benefit. One of the major factors influencing compliance is injection pain. Besides the injection device used, pain perception and local tissue reaction following...... 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...

  4. Moisture buffering capacity of highly absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Cerolini, S.; D' Orazio, M.; Stazi, A. [Department of Architecture, Construction and Structures (DACS), Faculty of Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60100 Ancona (Italy); Di Perna, C. [Department of Energetics, Faculty of Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60100 Ancona (Italy)

    2009-02-15

    This research investigates the possibility to use highly absorbing materials to dampen indoor RH% variations. The practical MBV of sodium polyacrylate, cellulose-based material, perlite and gypsum is evaluated for a daily cyclic exposure that alternates high (75%) and low (33%) RH% levels for 8 h and 16 h, respectively. The adjustment velocity to RH% variations and the presence of hysteretic phenomena are also presented. The cellulose-based material proves to be the most suitable for moisture buffering applications. Starting from this material's properties, the effect of thickness, vapour resistance factor ({mu}) and mass surface exchange coefficient (Z{sub v}) on sorption capacity is evaluated by the use of a numerical model. (author)

  5. Cost of riparian buffer zones: A comparison of hydrologically adapted site-specific riparian buffers with traditional fixed widths

    Science.gov (United States)

    Tiwari, T.; Lundström, J.; Kuglerová, L.; Laudon, H.; Öhman, K.; Ågren, A. M.

    2016-02-01

    Traditional approaches aiming at protecting surface waters from the negative impacts of forestry often focus on retaining fixed width buffer zones around waterways. While this method is relatively simple to design and implement, it has been criticized for ignoring the spatial heterogeneity of biogeochemical processes and biodiversity in the riparian zone. Alternatively, a variable width buffer zone adapted to site-specific hydrological conditions has been suggested to improve the protection of biogeochemical and ecological functions of the riparian zone. However, little is known about the monetary value of maintaining hydrologically adapted buffer zones compared to the traditionally used fixed width ones. In this study, we created a hydrologically adapted buffer zone by identifying wet areas and groundwater discharge hotspots in the riparian zone. The opportunity cost of the hydrologically adapted riparian buffer zones was then compared to that of the fixed width zones in a meso-scale boreal catchment to determine the most economical option of designing riparian buffers. The results show that hydrologically adapted buffer zones were cheaper per hectare than the fixed width ones when comparing the total cost. This was because the hydrologically adapted buffers included more wetlands and low productive forest areas than the fixed widths. As such, the hydrologically adapted buffer zones allows more effective protection of the parts of the riparian zones that are ecologically and biogeochemically important and more sensitive to disturbances without forest landowners incurring any additional cost than fixed width buffers.

  6. Developing suitable buffers to capture transport cycling behavior

    DEFF Research Database (Denmark)

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

    2014-01-01

    The association between neighborhood built environment and cycling has received considerable attention in health literature over the last two decades, but different neighborhood definitions have been used and it is unclear which one is most appropriate. Administrative or fixed residential spatial...... 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 that...... GPS tracks can help us understand where people go and stay during the day, which can help us link built environment with cycling. Analysis showed that the further people live from the city center, the more elongated are their GPS tracks, and the better an ellipse-shaped directional buffer captured...

  7. Buffering Implications for the Design Space of Streaming MEMS Storage

    OpenAIRE

    Khatib, Mohammed G.; Abelmann, Leon; Preas, Kathy

    2011-01-01

    Emerging nanotechnology-based systems encounter new non-functional requirements. This work addresses MEMS storage, an emerging technology that promises ultrahigh density and energy-efficient storage devices. We study the buffering requirement of MEMS storage in streaming applications. We show that capacity and lifetime of a MEMS device dictate the buffer size most of the time. Our study shows that trading off 10% of the optimal energy saving of a MEMS device reduces its buffer capacity by up ...

  8. A study on manufacturing and construction method of buffer

    Energy Technology Data Exchange (ETDEWEB)

    Chijimatsu, Masakazu; Sugita, Yutaka [Tokai Works, Waste Management and Fuel Cycle Research Center, Waste Isolation Research Division, Barrier Performance Group, Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan); Amemiya, Kiyoshi [Hazama Corp., Tokyo (Japan)

    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.)

  9. LATENCY-AWARE WRITE BUFFER RESOURCE CONTROL IN MULTITHREADED CORES

    OpenAIRE

    Shane Carroll; Wei-Ming Lin

    2016-01-01

    In a simultaneous multithreaded system, a core’s pipeline resources are sometimes partitioned and otherwise shared amongst numerous active threads. One mutual resource is the write buffer, which acts as an intermediary between a store instruction’s retirement from the pipeline and the store value being written to cache. The write buffer takes a completed store instruction from the load/store queue and eventually writes the value to the level-one data cache. Once a store is buffere...

  10. Effects of node buffer and capacity on network traffic

    International Nuclear Information System (INIS)

    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

  11. BUFFER SIZING FOR THE CRITICAL CHAIN PROJECT MANAGEMENT METHOD

    Directory of Open Access Journals (Sweden)

    A. Geekie

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Methods for sizing project and feeding buffers for critical chain project management are investigated. Experiments indicate that – in the absence of bias, and for certain classes of bias – buffer consumption is independent of the mean duration of a chain. Generally the popular method – a buffer size equal to 50% of the longest path leading to it – gives rise to excessively large buffers. Buffers sized according to the square root of the sum of squares perform well in the absence of bias, but with bias present the performance is unacceptably poor. A new approach to buffer sizing is proposed.

    AFRIKAANSE OPSOMMING: Metodes vir groottebepaling van projek- en saamvloeibuffers vir kritieke-ketting projekbestuur word ondersoek. Eksperimente dui daarop dat – in die afwesigheid van onewewigtigheid, en vir sekere tipes onewewigtigheid – bufferverbruik onafhanklik is van die gemiddelde lengte van ’n ketting. Oor die algemeen veroorsaak die metode van buffergrootte – gelyk aan 50% van die langste pad wat tot die buffer lei – onnodige groot buffers. Buffers bepaal met die metode van die vierkantswortel van die som van kwadrate, vaar goed in die afwesigheid van onewewigtigheid, maar vaar onaanvaarbaar swak wanneer onewewigtigheid teenwoordig is. ’n Nuwe metode vir die bepaling van buffergrootte word voorgestel.

  12. How Do Stream Buffers Reduce the Offsite Impact of Pollution?

    OpenAIRE

    Easton, Zachary M.

    2012-01-01

    Summarizes the importance of buffers to reduce pollution and specifically examines where they can be used, how they work, their limitations, required maintenance, performance levels, and expected cost.

  13. Buffers for biomass production in temperate European agriculture

    DEFF Research Database (Denmark)

    Christen, Benjamin; Dalgaard, Tommy

    2013-01-01

    Buffer strips on agricultural land have been shown to protect surface water quality by reducing erosion and diffuse pollution. They can also play a key role in nature conservation and flood risk mitigation as well as in the design of bioenergy landscapes resilient to changes in climate....... 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...

  14. Prevention of Buffer overflow Attack Blocker Using IDS

    Directory of Open Access Journals (Sweden)

    Pankaj B. Pawar

    2012-10-01

    Full Text Available Now a day internet threat takes a blended attack form, targetingindividual users to gain control over networks and data. BufferOverflow which is one of the most occurring securityvulnerabilities in a Computer’s world. Buffer Overflow occurswhile writing data to a buffer and it overruns the buffer'sboundary and overwrites it to a adjacent memory. The techniquesto exploit buffer overflow vulnerability vary per architecture,Operating system and memory region. There are variousexploitation which causes to buffer overflow attack as stackbased exploitation, heap based exploitation and choice ofprogramming language and many more. Which may result inerratic program behavior, including memory access errors,incorrect results, a crash or a breach of system security. C andC++ are the two programming languages which do not check thatdata has overwritten to an array that results to an buffer overflow.There are many more techniques which has been used forprotecting the Computer from buffer overflow attack We areproposing a novel techniques for preventing data loss duringthe transmission of images of different formats. In this paper wehave discuss and compare certain tools and techniques whichprevent buffer overflows. We have also discuss some moderntools and techniques with their pros and cons.

  15. Ventilation system with improved heat buffer; Ventilatieinrichting met verbeterde warmtebuffer

    Energy Technology Data Exchange (ETDEWEB)

    Akkerman, H.

    1995-10-02

    The invention concerns heat buffers of a ventilation system in combination with heat recovery. Hot and a cold air flows through the buffer elements alternately, regulated by a valve. The buffer elements are placed in an improved framework by which the surface area (and thus the efficiency) is increased. Also rain caps can be integrated such that freezing up does not occur anymore and the pollution slows down, which also improves the efficiency and reduces the number of maintenance inspections. Finally, coupling pieces can be installed, by which chinks can be prevented, which again reduces the loss of efficiency between the heat buffer modules. 2 figs.

  16. 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.

  17. Buffer Insertion for Bridges and Optimal Buffer Sizing for Communication Sub-System of Systems-on-Chip

    CERN Document Server

    Kallakuri, Sankalp S; Feinberg, Eugene A

    2011-01-01

    We have presented an optimal buffer sizing and buffer insertion methodology which uses stochastic models of the architecture and Continuous Time Markov Decision Processes CTMDPs. Such a methodology is useful in managing the scarce buffer resources available on chip as compared to network based data communication which can have large buffer space. The modeling of this problem in terms of a CT-MDP framework lead to a nonlinear formulation due to usage of bridges in the bus architecture. We present a methodology to split the problem into several smaller though linear systems and we then solve these subsystems.

  18. The buffer/container experiment: results, synthesis, issues

    International Nuclear Information System (INIS)

    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

  19. 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

  20. A multipurpose switched reluctance motor with a series commutation buffer

    Directory of Open Access Journals (Sweden)

    L.A. Vasil'ev

    2014-06-01

    Full Text Available In this paper, a power-supply circuit for a multipurpose switched reluctance motor with a series commutation buffer is presented. It is shown that a series buffer improves output characteristics of multipurpose switched reluctance motors under supply from a single-phase circuit and also lifts necessity of switching capacitors according to the motor power supply modes.

  1. 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%.

  2. 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.

  3. Buffer-Aided Relaying with Adaptive Link Selection

    DEFF Research Database (Denmark)

    Zlatanov, Nikola; Schober, Robert; Popovski, Petar

    2013-01-01

    decision threshold of the link selection policy smaller than the optimal one and derive a corresponding upper bound on the average delay. Furthermore, we propose a modified link selection protocol which avoids buffer overflow by limiting the queue size. Our analytical and numerical results show that buffer...

  4. BUFFER PROPERTIES OF SOIL MINERALS. PART 1. THEORETICAL ASPECTS

    Directory of Open Access Journals (Sweden)

    Povar Igor

    2013-12-01

    Full Text Available The key quantitative characteristics of the theory of buffer action for polycomponent mono- and two-phase systems have been derived. It is shown, that the buffer properties in relation to the solid phase components are amplified with an increase of solubility due to protolytic or complex formation equilibria in saturated solutions.

  5. BUFFER PROPERTIES OF SOIL MINERALS. PART 1. THEORETICAL ASPECTS

    OpenAIRE

    Povar Igor; Spinu Oxana

    2013-01-01

    The key quantitative characteristics of the theory of buffer action for polycomponent mono- and two-phase systems have been derived. It is shown, that the buffer properties in relation to the solid phase components are amplified with an increase of solubility due to protolytic or complex formation equilibria in saturated solutions.

  6. Effect of buffering on pharmacokinetics of ketoprofen enantiomers in man

    OpenAIRE

    Fuder, H.; Stiegler, S.; Wetzelsberger, N.; Wieckhorst, G.; Lange, R. de; Lücker, P W

    1997-01-01

    Aims Concomitant administration of magnesium hydroxide may affect the rate or extent of absorption of non-steroidal anti-inflammatory drugs. In order to find out whether or not buffering modifies the pharmacokinetics of ketoprofen, plasma concentration-time courses resulting from oral administration of unbuffered formulations were compared with those of buffered formulations.

  7. 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.

  8. Buffer erosion: An overview of concepts and potential safety consequences

    International Nuclear Information System (INIS)

    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

  9. ISA-Independent Scheduling Algorithm for Buffered Crossbar Switch

    Directory of Open Access Journals (Sweden)

    Dr. Kannan Balasubramanian

    2011-11-01

    Full Text Available Crossbars are an emerging technology in high speed router. In buffered crossbar switch a buffer is associated with each crossbar. Due to the introduction of crossbar buffers the input and output contentions are highly eliminated. Both the input and output port work independently and so the scheduling process is highly simplified. With a speed up of 2 it has been proved that 100% throughput can be achieved. In this paper we propose a 100% throughput scheduling algorithm without speedup called ISA. In ISA the scheduling decision is purely based on the state information of the local crosspoint buffer. So it is suited for a distributed implementation and it is highly scalable. The main advantage is the crosspoint use a buffer size of 1 which minimizes the hardware cost. Simulation results show that we achieve 100% throughput without any speedup.

  10. Molecular Buffers Permit Sensitivity Tuning and Inversion of Riboswitch Signals

    DEFF Research Database (Denmark)

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

    2016-01-01

    Predictable integration of foreign biological signals and parts remains a key challenge in the systematic engineering of synthetic cellular actuations, and general methods to improve signal transduction and sensitivity are needed. To address this problem we modeled and built a molecular signal...... buffer network in Saccharomyces cerevisiae inspired by chemical pH buffer systems. The molecular buffer system context-insulates a riboswitch enabling synthetic control of colony formation and modular signal manipulations. The riboswitch signal is relayed to a transcriptional activation domain of a split...... 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...

  11. Preliminary test on filling gap behavior of the swollen buffer in the engineering barrier system

    International Nuclear Information System (INIS)

    In geological disposal of the high-level radioactive waste (HLW), the engineered barrier system (EBS) (buffer, waste packages (capsulate the vitrified waste)) is installed in the space of a repository using the remote control technique due to protect workers from radiation. The block type buffer, as one of the candidate options of the installation of the buffer, has the gap between buffer and rock or waste package. In this case, the highly compacted buffer will be used to fill the gap by the swollen buffer. Swelling of the buffer is considered to begin from the surface of the buffer where groundwater infiltrates. Infiltration of groundwater into the buffer is considered to be 3 dimensional, because the gap and the infiltration points of the buffer are distributed spatially. Therefore, the scatter of the swelling points of the buffer causes the non-uniformity of the swelling of the buffer. Such non-uniformity of the swelling of the buffer will affect the thickness of the buffer between waste package and rock mass. Then, preliminary tests that simulate 3 dimensional filling gap behavior of the swollen buffer were performed. The test results showed the swollen buffer filled the gap rapidly. There is scatter of the density of the buffer early, but the tendency that the density of the buffer became uniformity with time was observed. It is considered that the swelling and fluidity of the buffer occurs simultaneously, the swelling of the buffer for filling the gap will affect the thickness of the buffer. (author)

  12. 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…

  13. Temperature Buffer Test. Final THM modelling

    International Nuclear Information System (INIS)

    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 only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the final THM modelling which was resumed subsequent to the dismantling operation. The main part of this work has been numerical modelling of the field test. Three different modelling teams have presented several model cases for different geometries and different degree of process complexity. Two different numerical codes, CodeBright and Abaqus, have been used. The modelling performed by UPC-Cimne using CodeBright, has been divided in three subtasks: i) analysis of the response observed in the lower part of the test, by inclusion of a number of considerations: (a) the use of the Barcelona Expansive Model for MX-80 bentonite; (b) updated parameters in the vapour diffusive flow term; (c) the use of a non-conventional water retention curve for MX-80 at high temperature; ii) assessment of a possible relation between the cracks observed in the bentonite blocks in the upper part of TBT, and the cycles of suction and stresses registered in that zone at the start of the experiment; and iii) analysis of the performance, observations and interpretation of the entire test. It was however not possible to carry out a full THM analysis until the end of the test due to convergence

  14. Temperature Buffer Test. Final THM modelling

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias; Malmberg, Daniel; Boergesson, Lennart; Hernelind, Jan [Clay Technology AB, Lund (Sweden); Ledesma, Alberto; Jacinto, Abel [UPC, Universitat Politecnica de Catalunya, Barcelona (Spain)

    2012-01-15

    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 only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the final THM modelling which was resumed subsequent to the dismantling operation. The main part of this work has been numerical modelling of the field test. Three different modelling teams have presented several model cases for different geometries and different degree of process complexity. Two different numerical codes, Code{sub B}right and Abaqus, have been used. The modelling performed by UPC-Cimne using Code{sub B}right, has been divided in three subtasks: i) analysis of the response observed in the lower part of the test, by inclusion of a number of considerations: (a) the use of the Barcelona Expansive Model for MX-80 bentonite; (b) updated parameters in the vapour diffusive flow term; (c) the use of a non-conventional water retention curve for MX-80 at high temperature; ii) assessment of a possible relation between the cracks observed in the bentonite blocks in the upper part of TBT, and the cycles of suction and stresses registered in that zone at the start of the experiment; and iii) analysis of the performance, observations and interpretation of the entire test. It was however not possible to carry out a full THM analysis until the end of the test due to

  15. Monitoring Liverworts to Evaluate the Effectiveness of Hydroriparian Buffers

    Science.gov (United States)

    Higgins, Kellina L.; Yasué, Maï

    2014-01-01

    In the coastal temperate rainforest of British Columbia (BC) in western Canada, government policies stipulate that foresters leave unlogged hydroriparian buffer strips up to 25 m on each side of streams to protect wildlife habitat. At present, studies on the effectiveness of these buffers focus on mammals, birds, and amphibians while there is comparably little information on smaller organisms such as liverworts in these hydroriparian buffers. To address this gap of knowledge, we conducted field surveys of liverworts comparing the percent cover and community composition in hydroriparian forested areas ( n = 4 sites, n = 32 plots with nested design) to hydroriparian buffer zones ( n = 4 sites, n = 32 plots). We also examined how substrate type affected the cover of liverworts. Liverwort communities in buffers were similar to those in riparian forest areas and most liverworts were found on downed wood. Thus, hydroriparian buffers of 25-35 m on each side in a coastal temperate rainforest effectively provide habitat for liverworts as long as downed wood is left intact in the landscape. Because liverworts are particularly sensitive to changes in humidity, these results may indicate that hydroriparian buffers are an effective management strategy for bryophytes and possibly for a range of other riparian species that are particularly sensitive to forestry-related changes in microclimate.

  16. Improved ultrastructure of marine invertebrates using non-toxic buffers

    Science.gov (United States)

    Montanaro, Jacqueline; Gruber, Daniela

    2016-01-01

    Many marine biology studies depend on field work on ships or remote sampling locations where sophisticated sample preservation techniques (e.g., high-pressure freezing) are often limited or unavailable. Our aim was to optimize the ultrastructural preservation of marine invertebrates, especially when working in the field. To achieve chemically-fixed material of the highest quality, we compared the resulting ultrastructure of gill tissue of the mussel Mytilus edulis when fixed with differently buffered EM fixatives for marine specimens (seawater, cacodylate and phosphate buffer) and a new fixative formulation with the non-toxic PHEM buffer (PIPES, HEPES, EGTA and MgCl2). All buffers were adapted for immersion fixation to form an isotonic fixative in combination with 2.5% glutaraldehyde. We showed that PHEM buffer based fixatives resulted in equal or better ultrastructure preservation when directly compared to routine standard fixatives. These results were also reproducible when extending the PHEM buffered fixative to the fixation of additional different marine invertebrate species, which also displayed excellent ultrastructural detail. We highly recommend the usage of PHEM-buffered fixation for the fixation of marine invertebrates. PMID:27069800

  17. Improved ultrastructure of marine invertebrates using non-toxic buffers.

    Science.gov (United States)

    Montanaro, Jacqueline; Gruber, Daniela; Leisch, Nikolaus

    2016-01-01

    Many marine biology studies depend on field work on ships or remote sampling locations where sophisticated sample preservation techniques (e.g., high-pressure freezing) are often limited or unavailable. Our aim was to optimize the ultrastructural preservation of marine invertebrates, especially when working in the field. To achieve chemically-fixed material of the highest quality, we compared the resulting ultrastructure of gill tissue of the mussel Mytilus edulis when fixed with differently buffered EM fixatives for marine specimens (seawater, cacodylate and phosphate buffer) and a new fixative formulation with the non-toxic PHEM buffer (PIPES, HEPES, EGTA and MgCl2). All buffers were adapted for immersion fixation to form an isotonic fixative in combination with 2.5% glutaraldehyde. We showed that PHEM buffer based fixatives resulted in equal or better ultrastructure preservation when directly compared to routine standard fixatives. These results were also reproducible when extending the PHEM buffered fixative to the fixation of additional different marine invertebrate species, which also displayed excellent ultrastructural detail. We highly recommend the usage of PHEM-buffered fixation for the fixation of marine invertebrates. PMID:27069800

  18. The effect of buffer zone width on biodiversity

    DEFF Research Database (Denmark)

    Navntoft, Søren; Sigsgaard, Lene; Kristensen, Kristian; Esbjerg, P

    Field margin management for conservation purposes is a way to protect both functional biodiversity and biodiversity per se without considerable economical loss as field margins are less productive. However, the effect of width of the buffer zone on achievable biodiversity gains has received little...... attention in previous studies. In this paper we report on finding for syrphids, spiders and carabids, three taxonomic groups with different mobility, all important for conservation biological control. For all groups we found an effect of buffer zone width on their density. A buffer width of 6m was the...

  19. An oxygen buffer for some peraluminous granites and metamorphic rocks.

    Science.gov (United States)

    Zen, E.

    1985-01-01

    The mineral assemblage biotite-garnet-muscovite-magnetite-quartz and its sub-sets are common in many peraluminous granites, schists and gneisses. If the biotite and garnet are reasonably iron-rich, then the system is a useful buffer for fO2. Available thermochemical data indicate that, in T-fO2 space, the buffer curve is located between the hematite-magnetite curve and the quartz-magnetite-fayalite curve, in a region that previously had no buffer curve applicable to peraluminous rocks. -J.A.Z.

  20. Buffer layers for REBCO films for use in superconducting devices

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Enhanced adhesion for LIGA microfabrication by using a buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Bajikar, Sateesh S.; DeCarlo, Francesco; Song, Joshua J.

    1998-05-22

    The present invention is an improvement on the LIGA microfabrication process wherein a buffer layer is applied to the upper or working surface of a substrate prior to the placement of a resist onto the surface of the substrate. The buffer layer is made from an inert low-Z material (low atomic weight), a material that absorbs secondary X-rays emissions from the substrate that are generated from the substrate upon exposure to a primary X-rays source. Suitable materials for the buffer layer include polyamides and polyimide. The preferred polyimide is synthesized from pyromellitic anhydride and oxydianiline (PMDA-ODA).

  2. 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.

  3. pH buffering in compacted bentonite

    International Nuclear Information System (INIS)

    In almost all high-level waste and spent fuel repository concepts, highly compacted bentonite in one form or another is the preferred material for backfilling and sealing. During re-saturation the bentonite swells and seals against the emplacement tunnels. The very low transmissivity to water movement and good sorption characteristics make compacted bentonite an extremely effective near-field diffusion barrier to the movement of radionuclides. The ability to give a chemically well founded pore water composition is essential since such knowledge is a pre-requisite for understanding sorption and diffusion processes, assessing the influence of long term groundwater-bentonite interactions and also predicting near-field solubilities and developing sorption data bases. In this context the pH of the pore water is of central importance, particularly for sorption. Almost invariably the compositions given for highly compacted bentonite pore waters are calculated values because reliable water samples are virtually impossible to obtain, even by squeezing under very high pressures. Assumptions and simplifications are made in the geochemical models used to perform such calculations and the predictions are seldom if ever tested. One of the main hypotheses in a recently proposed model for bentonite pore water was that the initial pH is determined by the state of the amphoteric surface hydroxy groups, ≡SOH type sites, and these buffer the pH of the pore water in to a value close to 8. Surface site types, site capacities and proto-lysis constants were obtained from previous montmorillonite titration measurements and were fixed in the calculations. The aim of this work was to test the Bradbury and Baeyens (2003) model in terms of its ability to the predict one of the most important parameters for any pore water, namely the pH. Tests against the real system are not practicable for the reasons mentioned above. Hence the experiments had to be indirect but nevertheless devised to

  4. Graphics’ Card Utility withWebGL and N-Buffering : Improving performance using N-buffer strategies with WebGL

    OpenAIRE

    Palm, Emanuel

    2014-01-01

    This thesis covers the utilization of N buffers in order to reduce resource contention on an abstract WebGL machine, and subsequently freeing up machine processing time. The buffers touched are frame buffers and vertex buffers. The paper also briefly covers the purpose and function of N buffering in relation to graphics and the function of a WebGL machine, the research and production of benchmark prototypes, some relevant benchmark results, and analysis and conclusions. The conclusion is made...

  5. Religion a Buffer Against Suicide for Women, Study Suggests

    Science.gov (United States)

    ... nlm.nih.gov/medlineplus/news/fullstory_159630.html Religion a Buffer Against Suicide for Women, Study Suggests ... encouraged as a form of meaningful social participation. Religion and spirituality may be an underappreciated resource that ...

  6. Radiation resistance of the natural microbial population in buffer materials

    Energy Technology Data Exchange (ETDEWEB)

    Stroes-Gascoyne, S.; Lucht, L.M.; Borsa, J.; Delaney, T.L.; Haveman, S.A.; Hamon, C.J. [AECL Research, Pinawa, Manitoba (Canada). Whiteshell Labs.

    1995-12-31

    The radiation sensitivity of naturally occurring microorganisms in buffer materials was investigated as well as the sensitivity of Bacillus subtillis spores and Acinetobacter radioresistens in a buffer matrix. The D{sub 10} values obtained in these radiation experiments varied from 0.34 to 1.68 kGy and it was calculated that the surface of a nuclear fuel waste container would be sterilized in 9 to 33 d after emplacement, depending on the type of container, and the initial bioburden. This suggests that formation of biofilms and microbially influenced corrosion would not be of concern of some time after emplacement. The results also indicated that sterilization throughout a 25 cm thick buffer layer is unlikely and that repopulation of the container surface after some time is a possibility, depending on the mobility of microbes in compacted buffer material.

  7. On the Behavioral Modeling of Integrated Circuit Output Buffers

    OpenAIRE

    Canavero, Flavio; Stievano, Igor Simone; Maio, Ivano Adolfo

    2003-01-01

    The properties of common behavioral macromodels for single ended CMOS integrated circuits output buffers are discussed with the aim of providing criteria for an effective use of possible modeling options

  8. Radiation resistance of the natural microbial population in buffer materials

    International Nuclear Information System (INIS)

    The radiation sensitivity of naturally occurring microorganisms in buffer materials was investigated as well as the sensitivity of Bacillus subtillis spores and Acinetobacter radioresistens in a buffer matrix. The D10 values obtained in these radiation experiments varied from 0.34 to 1.68 kGy and it was calculated that the surface of a nuclear fuel waste container would be sterilized in 9 to 33 d after emplacement, depending on the type of container, and the initial bioburden. This suggests that formation of biofilms and microbially influenced corrosion would not be of concern of some time after emplacement. The results also indicated that sterilization throughout a 25 cm thick buffer layer is unlikely and that repopulation of the container surface after some time is a possibility, depending on the mobility of microbes in compacted buffer material

  9. Religion a Buffer Against Suicide for Women, Study Suggests

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_159630.html Religion a Buffer Against Suicide for Women, Study Suggests ... encouraged as a form of meaningful social participation. Religion and spirituality may be an underappreciated resource that ...

  10. EnviroAtlas - Durham, NC - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  11. EnviroAtlas - Phoenix, AZ - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  12. EnviroAtlas - Portland, ME - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  13. EnviroAtlas - Des Moines, IA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  14. EnviroAtlas - Fresno, CA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  15. EnviroAtlas - Milwaukee, WI - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  16. EnviroAtlas - New York, NY - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  17. EnviroAtlas - Austin, TX - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  18. EnviroAtlas - New Bedford, MA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  19. EnviroAtlas - Pittsburgh, PA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  20. EnviroAtlas - Green Bay, WI - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  1. EnviroAtlas - Paterson, NJ - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  2. EnviroAtlas - Tampa, FL - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  3. EnviroAtlas - Portland, OR - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  4. EnviroAtlas - Memphis, TN - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  5. EnviroAtlas - Woodbine, IA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  6. Astrocytic Ion Dynamics: Implications for Potassium Buffering and Liquid Flow

    OpenAIRE

    Halnes, Geir; Pettersen, Klas H.; Øyehaug, Leiv; Rognes, Marie E.; Langtangen, Hans Petter; Einevoll, Gaute T.

    2016-01-01

    We review modeling of astrocyte ion dynamics with a specific focus on the implications of so-called spatial potassium buffering, where excess potassium in the extracellular space (ECS) is transported away to prevent pathological neural spiking. The recently introduced Kirchoff-Nernst-Planck (KNP) scheme for modeling ion dynamics in astrocytes (and brain tissue in general) is outlined and used to study such spatial buffering. We next describe how the ion dynamics of astrocytes may regulate mic...

  7. Fragmentation Impairs the Microclimate Buffering Effect of Tropical Forests

    OpenAIRE

    Ewers, Robert M; Banks-Leite, Cristina

    2013-01-01

    Background Tropical forest species are among the most sensitive to changing climatic conditions, and the forest they inhabit helps to buffer their microclimate from the variable climatic conditions outside the forest. However, habitat fragmentation and edge effects exposes vegetation to outside microclimatic conditions, thereby reducing the ability of the forest to buffer climatic variation. In this paper, we ask what proportion of forest in a fragmented ecosystem is impacted by altered micro...

  8. Current status of mechanical erosion studies of bentonite buffer

    International Nuclear Information System (INIS)

    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.)

  9. Buffer Capacity, Ecosystem Feedbacks, and Seawater Chemistry under Global Change

    OpenAIRE

    Robert J. Toonen; Atkinson, Marlin J; Thomas, Florence I. M.; Jury, Christopher P.

    2013-01-01

    Ocean acidification (OA) results in reduced seawater pH and aragonite saturation state (Ωarag), but also reduced seawater buffer capacity. As buffer capacity decreases, diel variation in seawater chemistry increases. However, a variety of ecosystem feedbacks can modulate changes in both average seawater chemistry and diel seawater chemistry variation. Here we model these effects for a coastal, reef flat ecosystem. We show that an increase in offshore pCO2 and temperature (to 900 µatm and + 3 ...

  10. The buffer/container experiment design and construction report

    International Nuclear Information System (INIS)

    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

  11. 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

  12. Full scale tests of moisture buffer capacity of wall materials

    OpenAIRE

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

    2005-01-01

    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 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 eff...

  13. A Bicriteria Approximation for the Reordering Buffer Problem

    CERN Document Server

    Barman, Siddharth; Umboh, Seeun

    2012-01-01

    In the reordering buffer problem (RBP), a server is asked to process a sequence of requests lying in a metric space. To process a request the server must move to the corresponding point in the metric. The requests can be processed slightly out of order; in particular, the server has a buffer of capacity k which can store up to k requests as it reads in the sequence. The goal is to reorder the requests in such a manner that the buffer constraint is satisfied and the total travel cost of the server is minimized. The RBP arises in many applications that require scheduling with a limited buffer capacity, such as scheduling a disk arm in storage systems, switching colors in paint shops of a car manufacturing plant, and rendering 3D images in computer graphics. We study the offline version of RBP and develop bicriteria approximations. When the underlying metric is a tree, we obtain a solution of cost no more than 9OPT using a buffer of capacity 4k + 1 where OPT is the cost of an optimal solution with buffer capacit...

  14. 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.

  15. D-buffer: irregular image data storage made practical

    Science.gov (United States)

    Lipowski, J. K.

    2013-03-01

    Modern hardware accelerated graphics pipelines are designed to operate on data in a so called streaming model. To process the data in this model one needs to impose some restrictions on input and output argument's (most frequently represented by a two-dimensional frame buffer) memory structure. The output data regularity is obvious when we consider rasterizing hardware architecture, which draws 3D polygons using depth buffer to resolve the visible surface problem. But recently the user's needs surpass those restrictions with increasing frequency. In this work we formulate and present new methods of irregular frame buffer storage and ordering. The so called deque buffer (or D-buffer) allows us to decrease the amount of memory used for storage as well as the memory latency cost by using pixel data ordering. Our findings are confirmed by experimental results that measure the processing time, which is up to four times shorter, when compared with previous work by other authors. We also include a detailed description of algorithms used for D-buffer construction on the last three consumer-grade graphics hardware architectures, as a guide for other researchers and a development aid for practitioners. The only theoretical requirement imposed by our method is the use of memory model with linear address space.

  16. 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

  17. Relation Between Buffer Size and RISC Core Performance

    Institute of Scientific and Technical Information of China (English)

    ZHOULi; YAOQingdong; LIUPeng; LIDongxiao

    2003-01-01

    In high definition television (HDTV)source decoder system, all data and instructions processed by function models are inputted and outputted via bus which is controlled by bus arbitration unit (BAU). Effi-cient bus architecture plays an important role in optimiz-ing system performance. This paper proposes two models to evaluate how buffer size and priority scheme in BAU can affect HDTV decoder system performance. Store proba-bility and buffer size (SP-BS) model splits time of write into two parts which is determined by write buffer size and priority scheme respectively, and obtains the quantita-tive relation between system performance and write buffer size for different priority scheme. Capability performance formula (CPF) model is used to investigate the influence of read buffer size on system performance that is in di-rect proportion to the number of read request arriving at BAU. According to the models, optimal buffer size with the highest performance/cost ratio for be nchmarks can beobtained.

  18. 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.

  19. Calmodulin as a major calcium buffer shaping vesicular release and short-term synaptic plasticity: facilitation through buffer dislocation

    OpenAIRE

    Yulia Timofeeva; Kirill Volynski

    2015-01-01

    Action potential-dependent release of synaptic vesicles and short-term synaptic plasticity are dynamically regulated by the endogenous Ca(2+) buffers that shape [Ca(2+)] profiles within a presynaptic bouton. Calmodulin is one of the most abundant presynaptic proteins and it binds Ca(2+) faster than any other characterized endogenous neuronal Ca(2+) buffer. Direct effects of calmodulin on fast presynaptic Ca(2+) dynamics and vesicular release however have not been studied in detail. Using expe...

  20. Production flow synchronisation versus buffer capacities in assembly systems

    Directory of Open Access Journals (Sweden)

    D. Krenczyk

    2008-07-01

    Full Text Available Purpose: The goal of the considerations carried-out in that paper is the determination of the system synchronisation conditions. Those conditions concern capacities of system buffers. The fulfilment of the developed conditions should guarantee the production flow synchronisation into the expected steady state determined by the system bottleneck. In analysed assembly system rhythmic concurrent production with wide assortment is realised.Design/methodology/approach: The considerations presented in that paper are rooted in the authority method called Requirements and Possibilities Balance Method (RPBM. The experiments in the computer simulations programmes have been carried-out within the confines of the researches. The computer simulation models of the assembly systems using Taylor II for Windows and Enterprise Dynamics have been built.Findings: There are two kinds of system buffers: the entrance buffers and the inter-resources buffers in the assembly systems. The interdependences informing about the required number of elements allocated into the system buffers in order to the production realisation during the first cycle of the system steady state has been formulated. Moreover, the minimal buffer capacities have been determined.Research limitations/implications: The developed interdependences constitute the first step towards formulation of the automatic method designed for the automatic construction of rules controlling the system work during system transition state. That method should enable the automation of the system buffers filling-up.Practical implications: The presented system synchronisation conditions can become an integrated part of existing authority computer system. It aids the decision-making process connected with production planning and control.Originality/value: To develop the interdependences is the main achievement of the given paper. The presented approach permits to solve the problem concerning the production flow

  1. Message communications of particular message types between compute nodes using DMA shadow buffers

    Science.gov (United States)

    Blocksome, Michael A.; Parker, Jeffrey J.

    2010-11-16

    Message communications of particular message types between compute nodes using DMA shadow buffers includes: receiving a buffer identifier specifying an application buffer having a message of a particular type for transmission to a target compute node through a network; selecting one of a plurality of shadow buffers for a DMA engine on the compute node for storing the message, each shadow buffer corresponding to a slot of an injection FIFO buffer maintained by the DMA engine; storing the message in the selected shadow buffer; creating a data descriptor for the message stored in the selected shadow buffer; injecting the data descriptor into the slot of the injection FIFO buffer corresponding to the selected shadow buffer; selecting the data descriptor from the injection FIFO buffer; and transmitting the message specified by the selected data descriptor through the data communications network to the target compute node.

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

    International Nuclear Information System (INIS)

    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

  3. Thermo-hydro-mechanical modelling of buffer, synthesis report

    International Nuclear Information System (INIS)

    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 CODEBRIGHT 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

  4. Effect of various commercial buffers on sperm viability and capacitation.

    Science.gov (United States)

    Andrisani, Alessandra; Donà, Gabriella; Ambrosini, Guido; Bonanni, Guglielmo; Bragadin, Marcantonio; Cosmi, Erich; Clari, Giulio; Armanini, Decio; Bordin, Luciana

    2014-08-01

    A wide variety of sperm preparation protocols are currently available for assisted conception. They include density gradient separation and washing methods. Both aim at isolating and capacitating as much motile sperm as possible for subsequent oocyte fertilization. The aim of this study was to examine the effects of four commercial sperm washing buffers on sperm viability and capacitation. Semen samples from 48 healthy donors (normal values of sperm count, motility, morphology, and volume) were analyzed. After separation (density gradient 40/80%), sperm were incubated in various buffers then analysed for reactive oxygen species (ROS) production, viability, tyrosine phosphorylation (Tyr-P), cholera toxin B subunit (CTB) labeling, and the acrosome reaction (AR). The buffers affected ROS generation in various ways resulting either in rapid cell degeneration (when the amount of ROS was too high for cell survival) or the inability of the cells to maintain correct functioning (when ROS were too few). Only when the correct ROS generation curve was maintained, suitable membrane reorganization, evidenced by CTB labeling was achieved, leading to the highest percentages of both Tyr-P- and acrosome-reacted-cells. Distinguishing each particular pathological state of the sperm sample would be helpful to select the preferred buffer treatment since both ROS production and membrane reorganization can be significantly altered by commercial buffers. PMID:24673547

  5. Lot A2 test, THC modelling of the bentonite buffer

    Science.gov (United States)

    Itälä, Aku; Olin, Markus; Lehikoinen, Jarmo

    Finnish spent nuclear fuel is planned to be disposed of deep in the crystalline bedrock of the Olkiluoto island. In such a repository, the role of the bentonite buffer is considered to be central. The initially unsaturated bentonite emplaced around a spent-fuel canister will become fully saturated by the groundwater from the host rock. In order to assess the long-term safety of a deep repository, it is essential to determine how temperature influences the chemical stability of bentonite. The aim of this study was to achieve an improved understanding of the factors governing the thermo-hydro-chemical evolution of the bentonite buffer subject to heat generation from the disposed fuel and in contact with a highly permeable rock fracture intersecting a canister deposition hole. TOUGHREACT was used to model a test known as the long-term test of buffer material adverse-2, which was conducted at the Äspö hard rock laboratory in Sweden. The results on the evolution of cation-exchange equilibria, bentonite porewater chemistry, mineralogy, and saturation of the buffer are presented and discussed. The calculated model results show similarity to the experimental results. In particular, the spatial differences in the saturation and porewater chemistry of the bentonite buffer were clearly visible in the model.

  6. Lot A2 test, THC modelling of the bentonite buffer

    International Nuclear Information System (INIS)

    Finnish spent nuclear fuel is planned to be disposed of deep in the crystalline bedrock of the Olkiluoto island. In such a repository, the role of the bentonite buffer is considered to be central. The initially unsaturated bentonite emplaced around a spent-fuel canister will become fully saturated by the groundwater from the host rock. In order to assess the long-term safety of a deep repository, it is essential to determine how temperature influences the chemical stability of bentonite. The aim of this study was to achieve an improved understanding of the factors governing the thermo-hydro-chemical evolution of the bentonite buffer subject to heat generation from the disposed fuel and in contact with a highly permeable rock fracture intersecting a canister deposition hole. TOUGHREACT was used to model a test known as the long-term test of buffer material adverse-2, which was conducted at the Aespoe hard rock laboratory in Sweden. The results on the evolution of cation-exchange equilibria, bentonite pore water chemistry, mineralogy, and saturation of the buffer are presented and discussed. The calculated model results show similarity to the experimental results. In particular, the spatial differences in the saturation and pore water chemistry of the bentonite buffer were clearly visible in the model. (authors)

  7. Evaluations of composition for buffer materials based on genetic algorithms

    International Nuclear Information System (INIS)

    To provide an overall functional evaluations of buffer materials, this study attempted to investigate the relationships among the engineering properties, plastic index (PI), compaction efficiency, hydraulic conductivity(k); sorption properties, distribution ratio(Rd) for some buffer materials composed of quartz sand and bentonite. According to engineering and sorption properties, the optimal composition can be found out with some optimal approaches. However, a genetic algorithm (GA) is a robust method for searching the optimum solution to a complex problem and widely is applied to many different topics. It is a search algorithm based upon mechanics of natural selection, derived from the theory of natural evolution. The study of genetic algorithms (GAS) has developed into powerful optimization approach since 1970, so this study tries to apply GAS to this problem. Under both synthetic groundwater (GW) and seawater (SW) conditions, the composition of quartz sand and bentonite was evaluated by associating engineering and sorption properties. Due to ends of experiments, this study assumes linearly proportional relationship among bentonite content of buffer materials, PI, k, and sorption properties. And GAS was carried out using a population size of 50, a crossover rate of 0,5, and a mutation rate of 0,1. The final results based on genetic algorithms are consistent with consequences of previous tests. From the viewpoints of associated engineering and sorption properties, the buffer materials nearly containing 70% bentonite are probably the most favorable choice. These results will show a determination of more effective buffer material composition. (authors)

  8. Buffer layers on metal alloy substrates for superconducting tapes

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

    2004-10-05

    An article including a substrate, at least one intermediate layer upon the surface of the substrate, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the at least one intermediate layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected I.sub.c 's of over 200 Amperes across a sample 1 cm wide.

  9. Analysis and test verification of control rod buffer in HTR

    International Nuclear Information System (INIS)

    The thin-walled shell buffer in high temperature gas-cooled reactor (HTR) was designed for absorbing the kinetic energy of the control rod drop in the drive line fracture accident. The thin-walled cylinder structure satisfying the requirements of actual working condition was design by using the energy absorption model of the classical cylinder shell under axial pressure. By using ABAQUS/explicit with J-C constitutive model, the finite element models of both the real reactor condition and the test condition were built to simulate the collision. Based on the analysis results, the control rod fall- down test was designed and implemented. The test results demonstrate that stable pro gressive buckling occurs when the full size buffer is impacted by equiponderance test bar, and the buffer can reduce the crush force effectively and protect the graphite from being destroyed. The analysis results show that the test model can represent and envelope the real condition in reactor. (authors)

  10. Hydrothermal stability of bentonite-based buffer materials

    International Nuclear Information System (INIS)

    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

  11. Buffer-gas effects on dark resonances: Theory and experiment

    Science.gov (United States)

    Erhard, Michael; Helm, Hanspeter

    2001-04-01

    Dark resonances with widths below 30 Hz have been observed in a rubidium cell filled with neon as buffer gas at room temperature. We compare an approximate analytic solution of a Λ system to our data and show that under our experimental conditions the presence of the buffer gas reduces the power broadening of the dark resonances by two orders of magnitude. We also present numerical calculations that take into account the thermal motion and velocity-changing collisions with the buffer-gas atoms. The resulting dark-resonance features exhibit strong Dicke-type narrowing effects and thereby explain the elimination of Doppler shifts and Doppler broadening, leading to observation of a single ultranarrow dark line.

  12. Buffer Management Algorithm Design and Implementation Based on Network Processors

    CERN Document Server

    Fang, Yechang; Pan, Deng; Sun, Zhuo

    2010-01-01

    To solve the parameter sensitive issue of the traditional RED (random early detection) algorithm, an adaptive buffer management algorithm called PAFD (packet adaptive fair dropping) is proposed. This algorithm supports DiffServ (differentiated services) model of QoS (quality of service). In this algorithm, both of fairness and throughput are considered. The smooth buffer occupancy rate function is adopted to adjust the parameters. By implementing buffer management and packet scheduling on Intel IXP2400, the viability of QoS mechanisms on NPs (network processors) is verified. The simulation shows that the PAFD smoothes the flow curve, and achieves better balance between fairness and network throughput. It also demonstrates that this algorithm meets the requirements of fast data packet processing, and the hardware resource utilization of NPs is higher.

  13. Piping and erosion in buffer and backfill materials. Current knowledge

    International Nuclear Information System (INIS)

    The water inflow into the deposition holes and tunnels in a repository will mainly take place through fractures in the rock and will lead to that the buffer and backfill will be wetted and homogenised. But in general the buffer and backfill cannot absorb all water that runs through a fracture, which leads to that a water pressure will be generated in the fracture when the inflow is hindered. If the counter pressure and strength of the buffer or backfill is insufficiently high, piping and subsequent erosion may take place. The processes and consequences of piping and erosion have been studied in some projects and several laboratory test series in different scales have been carried through. This brief report describes these tests and the results and conclusions that have emerged. The knowledge of piping and erosion is insufficient today and additional studies are needed and running

  14. On the risk of liquefaction of buffer and backfill

    International Nuclear Information System (INIS)

    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/m3 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/m3. 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

  15. Optimization of buffer gas pressure for Rb atomic magnetometer

    Science.gov (United States)

    Chen, Chang; Liu, Xiaohu; Qu, Tianliang; Yang, Kaiyong

    2015-08-01

    The optimization of buffer gas pressure is very important to improve the performance of the rubidium (Rb) atomic magnetometer. In this paper we briefly introduce the basic principle and the experimental method of the rubidium magnetometer based on Faraday rotation effect, and describe the factors affecting the magnetometer sensitivity, then analyze and summarize the mechanism of the influence of spin-exchange, spin-destruction collisions, radiation trapping and the spin diffusion on spin relaxation of Rb atoms. Based on this, the relationship between the rubidium magnetometer sensitivity, the spin relaxation rate and the gas chamber conditions (buffer gas pressure, the bubble radius, measuring temperature) is established. Doing calculations by the simulation software, how the magnetometer sensitivity and the relaxation rate vary with the gas chamber conditions can be seen; finally, the optimal values of the buffer gas pressure under certain gas chamber conditions are obtained. The work is significant for the engineering development of rubidium magnetometer.

  16. Moisture Buffer Performance of a Fully Furnished Room

    DEFF Research Database (Denmark)

    Svennberg, Kaisa; Hedegaard, Lone Grønbæk; Rode, Carsten

    2004-01-01

    contribute to the moisture buffer capacity of the room. There is few studies made on the impact of furnishing materials in comparison with traditional building materials this paper will present such a study conducted in a full scale climate test cell. A series of experiments have been carried out in a......The moisture buffer capacity of hygroscopic materials can be used to moderate the relative humidity of indoor air as well as moisture content variations in building materials and furnishing. Since moisture plays a significant role in the development of many processes that affect the quality of the...... indoor air, such as growth of house dust mites, emissions from materials and mould growth it is anticipated that the moisture buffer effect can help to ensure healthier indoor environments. The building materials as well as furniture and other furnishing materials exposed to the indoor air will...

  17. 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

    , the buffer performance is investigated first for the untreated material, then after adding rendering on the surfaces, and finally with latex paint. Similarly for the walls of plasterboard construction, the buffer effects are investigated first for the insulation (cellulose or mineral wool), then after...... adding untreated plasterboards as cladding, and finally with additional latex paint. The walls were exposed to cyclic humidity variations like in an inhabited indoor environment, and the response of the indoor humidity was followed over time. The investigations also comprised simultaneous determination...... strongly reduced even with the supposedly highly vapour permeable rendering finish, not to mention the case when the latex paint was used. In the same way, the experiments for the plaster board construction demonstrated how cellulose insulation, as a very hygroscopic material, is a good buffer compared to...

  18. Cascaded Optical Buffer Based on Nonlinear Polarization Rotation in Semiconductor Optical Amplifiers

    Institute of Scientific and Technical Information of China (English)

    CHENG Mu; WU Chong-Qing; LIU Hua

    2008-01-01

    A cascaded buffer based on nonlinear polarization rotation in semiconductor optical amplifiers is proposed, which is suitable for fast reconfiguration of buffering time at picoseconds. With the proposed buffer, sixty different buffer times are demonstrated at 2.5 Gb/s.

  19. Ethanol contamination in commercial buffers: ethanol contaminating tris-maleate and other commercial buffers induces germ tube formation in Candida albicans.

    OpenAIRE

    Pollack, J H; Hashimoto, T

    1984-01-01

    Evidence is presented for the presence of trace amounts of ethanol in certain commercial buffers. It was shown that germ tube formation occurring in Candida albicans suspended in the buffers was due to the contaminating ethanol.

  20. Influence of glyphosate on the copper dissolution in phosphate buffer

    Science.gov (United States)

    Coutinho, C. F. B.; Silva, M. O.; Machado, S. A. S.; Mazo, L. H.

    2007-01-01

    The electrochemical behavior of copper microelectrode in phosphate buffer in the presence of glyphosate was investigated by electrochemical techniques. It was observed that the additions of glyphosate in the phosphate buffer increased the anodic current of copper microelectrode and the electrochemical dissolution was observed. This phenomenon could be associated with the Cu(II) complexation by glyphosate forming a soluble complex. Physical characterization of the surface showed that, in absence of glyphosate, an insoluble layer covered the copper surface; on the other hand, in presence of glyphosate, it was observed a corroded copper surface with the formation of glyphosate complex in solution.

  1. Moisture buffering and its consequence in whole building hygrothermal modeling

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2008-01-01

    Moisture absorption and desorption of materials in contact with indoor air of buildings can be used as a passive, i.e., nonmechanical, way to moderate the variation of indoor humidity. This phenomenon, which is recognized as,moisture buffering', could potentially be used as an attractive feature of...... for ventilation if indoor humidity is a parameter for controlling ventilation rate, 2. it is possible to improve the perceived acceptability of indoor air, as judged by the temperature and humidity of the air, by using moisture buffering to control the indoor humidity. The results of the whole...

  2. The Cyclical Behaviour of European Bank Capital Buffers

    OpenAIRE

    Jokipii, Terhi; Milne, Alistair

    2007-01-01

    Using an unbalanced panel of commercial, savings and co-operative banks for the years 1997 to 2004 we examine the cyclical behaviour of European bank capital buffers. After controlling for other potential de-terminants of bank capital, we find that capital buffers of the banks in the accession countries (RAM) have a significant positive relationship with the cycle, while for those in the EU15 and the EA and the combined EU25 the relationship is significantly negative. We additionally find fai...

  3. Thermo-Hydraulic Modelling of Buffer and Backfill

    International Nuclear Information System (INIS)

    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. CODEBRIGHT 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland [Geodevelopment AB, Lund (Sweden)

    2001-12-01

    Improved technology and prospection yielding more pure and homogeneous raw materials for preparing buffers and backfills will ultimately outdate the clays and ballast materials described in the present part of the Handbook. It describes experimentally investigated materials of potential use in repositories but other, more suitable materials will replace them in the future. The Handbook will hence have to be reviewed regularly, making room for superior materials in future, upgraded Handbook versions. Buffer is the term for dense clay used for embedment of canisters with highly radioactive waste, while backfill is soil used for filling tunnels and shafts in repositories. Examples of soil materials of potential use as buffers and backfills in repositories of KBS-3 type are described in this part of the Handbook. They are: smectitic clay materials intended for preparation of buffers (canister-embedding clay) and used as clay component in artificially prepared tunnel and shaft backfills consisting of mixtures of clay and ballast. Ballast materials intended for backfilling of tunnels and shafts and used as components of artificially prepared backfills. Smectitic natural clay soils intended for use as buffers and backfills. Very fine-grained smectite clay used as grout for sealing rock fractures. In this part of the Handbook for Buffers and Backfills, description of various candidate materials will be made with respect to their mineral composition and physical properties, with respect to the groundwater chemistry that can be expected in a deep repository in Swedish bedrock. Chapter 3 deals with smectitic clay materials intended for embedment of heat-producing canisters with highly radioactive waste. Focus is on the nature of the buffer constituents, i. e. the smectite content, the non-expanding clay minerals colloidal and the accessory non-clay minerals as well as amorphous matter and organic substances. The dominant part of the chapter describes the occurrence and origin

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

    International Nuclear Information System (INIS)

    Improved technology and prospection yielding more pure and homogeneous raw materials for preparing buffers and backfills will ultimately outdate the clays and ballast materials described in the present part of the Handbook. It describes experimentally investigated materials of potential use in repositories but other, more suitable materials will replace them in the future. The Handbook will hence have to be reviewed regularly, making room for superior materials in future, upgraded Handbook versions. Buffer is the term for dense clay used for embedment of canisters with highly radioactive waste, while backfill is soil used for filling tunnels and shafts in repositories. Examples of soil materials of potential use as buffers and backfills in repositories of KBS-3 type are described in this part of the Handbook. They are: smectitic clay materials intended for preparation of buffers (canister-embedding clay) and used as clay component in artificially prepared tunnel and shaft backfills consisting of mixtures of clay and ballast. Ballast materials intended for backfilling of tunnels and shafts and used as components of artificially prepared backfills. Smectitic natural clay soils intended for use as buffers and backfills. Very fine-grained smectite clay used as grout for sealing rock fractures. In this part of the Handbook for Buffers and Backfills, description of various candidate materials will be made with respect to their mineral composition and physical properties, with respect to the groundwater chemistry that can be expected in a deep repository in Swedish bedrock. Chapter 3 deals with smectitic clay materials intended for embedment of heat-producing canisters with highly radioactive waste. Focus is on the nature of the buffer constituents, i. e. the smectite content, the non-expanding clay minerals colloidal and the accessory non-clay minerals as well as amorphous matter and organic substances. The dominant part of the chapter describes the occurrence and origin

  6. Calmodulin as a major calcium buffer shaping vesicular release and short-term synaptic plasticity: facilitation through buffer dislocation

    Directory of Open Access Journals (Sweden)

    Yulia Timofeeva

    2015-07-01

    Full Text Available Action potential-dependent release of synaptic vesicles and short-term synaptic plasticity are dynamically regulated by the endogenous Ca2+ buffers that shape [Ca2+] profiles within a presynaptic bouton. Calmodulin is one of the most abundant presynaptic proteins and it binds Ca2+ faster than any other characterized endogenous neuronal Ca2+ buffer. Direct effects of calmodulin on fast presynaptic Ca2+ dynamics and vesicular release however have not been studied in detail. Using experimentally constrained three-dimensional diffusion modeling of Ca2+ influx–exocytosis coupling at small excitatory synapses we show that, at physiologically relevant concentrations, Ca2+ buffering by calmodulin plays a dominant role in inhibiting vesicular release and in modulating short-term synaptic plasticity. We also propose a novel and potentially powerful mechanism for short-term facilitation based on Ca2+-dependent dynamic dislocation of calmodulin molecules from the plasma membrane within the active zone.

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

    International Nuclear Information System (INIS)

    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.)

  8. 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.

  9. Separated Control and Data Stacks to Mitigate Buffer Overflow Exploits

    Directory of Open Access Journals (Sweden)

    Christopher Kugler

    2015-10-01

    Full Text Available Despite the fact that protection mechanisms like StackGuard, ASLR and NX are widespread, the development on new defense strategies against stack-based buffer overflows has not yet come to an end. In this article, we present a novel compiler-level protection called SCADS: Separated Control and Data Stacks that protects return addresses and saved frame pointers on a separate stack, called the control stack. In common computer programs, a single user mode stack is used to store control information next to data buffers. By separating control information from the data stack, we can protect sensitive pointers of a program’s control flow from being overwritten by buffer overflows. To substantiate the practicability of our approach, we provide SCADS as an open source patch for the LLVM compiler infrastructure. Focusing on Linux and FreeBSD running on the AMD64 architecture, we show compatibility, security and performance results. As we make control flow information simply unreachable for buffer overflows, many exploits are stopped at an early stage of progression with only negligible performance overhead.

  10. A Constant Factor Approximation Algorithm for Reordering Buffer Management

    CERN Document Server

    Avigdor-Elgrabli, Noa

    2012-01-01

    In the reordering buffer management problem (RBM) a sequence of $n$ colored items enters a buffer with limited capacity $k$. When the buffer is full, one item is removed to the output sequence, making room for the next input item. This step is repeated until the input sequence is exhausted and the buffer is empty. The objective is to find a sequence of removals that minimizes the total number of color changes in the output sequence. The problem formalizes numerous applications in computer and production systems, and is known to be NP-hard. We give the first constant factor approximation guarantee for RBM. Our algorithm is based on an intricate "rounding" of the solution to an LP relaxation for RBM, so it also establishes a constant upper bound on the integrality gap of this relaxation. Our results improve upon the best previous bound of $O(\\sqrt{\\log k})$ of Adamaszek et al. (STOC 2011) that used different methods and gave an online algorithm. Our constant factor approximation beats the super-constant lower b...

  11. NITROUS OXIDE EMISSIONS FROM RIPARIAN BUFFERS AND TREATMENT WETLANDS

    Science.gov (United States)

    Riparian buffers and treatment wetlands are used throughout the world for the protection of water bodies from nonpoint source pollution, particularly nitrogen. Yet, relatively few studies of riparian or treatment wetland denitrification consider the production of nitrous oxide. Nitrous oxide emissio...

  12. Evaluating uncertainty in E. coli retention in vegetated buffer strips

    Science.gov (United States)

    Vegetated buffer strips (VFS) separate fields and pastures from streams and other water bodies and can serve as barriers that prevent sediment and agricultural chemicals from entering waterways and spoiling them. Growing concern about the manure-borne pathogens as water pollutants defines the need t...

  13. 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.

  14. Buffer construction technique by means of granular bentonite

    International Nuclear Information System (INIS)

    Buffer construction technology using bentonite pellets as filling material is one of the promising technologies for enhancing the ease of buffer construction. In this study, a bentonite pellet filling test was conducted, using a filling system equipped with a screw conveyor system, in a full-scale simulated disposal drift. A simulated waste disposal drift configured as a half-cross-section model with a height of 2.22 m and a length of 6.0 m was constructed for the test, and two dummy overpacks were placed in the drift. The filling test was conducted in two phases. The average dry density of the buffer fill was 1.29 Mg/m3, which was close to the target value. The angle of repose was approximately 40 degrees. The test results indicate that the buffer construction technology using screw conveyor system for pellet conveyance in a waste disposal drift is a promising technology of the disposal of high level radioactive wastes. (author)

  15. New online program with encoder and memory buffer modules

    International Nuclear Information System (INIS)

    A new online program using a new data acquisition system consisting of encoder and memory buffer modules is developed for the meson spectroscopy experiment, E64, at the KEK proton synchrotron. The program has a feature of a high-speed and high-rate data acquisition. It is also simple, feasible and easily extensible. (author)

  16. VLSI scaling methods and low power CMOS buffer circuit

    International Nuclear Information System (INIS)

    Device scaling is an important part of the very large scale integration (VLSI) design to boost up the success path of VLSI industry, which results in denser and faster integration of the devices. As technology node moves towards the very deep submicron region, leakage current and circuit reliability become the key issues. Both are increasing with the new technology generation and affecting the performance of the overall logic circuit. The VLSI designers must keep the balance in power dissipation and the circuit's performance with scaling of the devices. In this paper, different scaling methods are studied first. These scaling methods are used to identify the effects of those scaling methods on the power dissipation and propagation delay of the CMOS buffer circuit. For mitigating the power dissipation in scaled devices, we have proposed a reliable leakage reduction low power transmission gate (LPTG) approach and tested it on complementary metal oxide semiconductor (CMOS) buffer circuit. All simulation results are taken on HSPICE tool with Berkeley predictive technology model (BPTM) BSIM4 bulk CMOS files. The LPTG CMOS buffer reduces 95.16% power dissipation with 84.20% improvement in figure of merit at 32 nm technology node. Various process, voltage and temperature variations are analyzed for proving the robustness of the proposed approach. Leakage current uncertainty decreases from 0.91 to 0.43 in the CMOS buffer circuit that causes large circuit reliability. (semiconductor integrated circuits)

  17. Diazinon and permethrin mitigation across a grass-wetland buffer

    Science.gov (United States)

    Various management practices have been proposed to help alleviate deleterious effects of pesticides associated with agricultural runoff. Vegetated buffers of different designs are often used as edge-of-field treatment practices. Two experimental systems, a control (no vegetation) and a grass-wetla...

  18. ON OPTIMAL LOCAL BUFFER ALLOCATION IN FLEXIBLE MANUFACTURING SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    An optimal design problem of local buffer allocation in the FMS is discussed in order to maximize a reward earned from processed jobs at all workstations. Structural properties of the optimal design problem are analyzed for the model with two job routing policies. Based on these properties, approaches to optimal solutions are given.

  19. Effects of terrestrial buffer zones on amphibians on golf courses.

    Directory of Open Access Journals (Sweden)

    Holly J Puglis

    Full Text Available A major cause of amphibian declines worldwide is habitat destruction or alteration. Public green spaces, such as golf courses and parks, could serve as safe havens to curb the effects of habitat loss if managed in ways to bolster local amphibian communities. We reared larval Blanchard's cricket frogs (Acris blanchardi and green frogs (Rana clamitans in golf course ponds with and without 1 m terrestrial buffer zones, and released marked cricket frog metamorphs at the golf course ponds they were reared in. Larval survival of both species was affected by the presence of a buffer zone, with increased survival for cricket frogs and decreased survival for green frogs when reared in ponds with buffer zones. No marked cricket frog juveniles were recovered at any golf course pond in the following year, suggesting that most animals died or migrated. In a separate study, we released cricket frogs in a terrestrial pen and allowed them to choose between mown and unmown grass. Cricket frogs had a greater probability of using unmown versus mown grass. Our results suggest that incorporating buffer zones around ponds can offer suitable habitat for some amphibian species and can improve the quality of the aquatic environment for some sensitive local amphibians.

  20. Creating a replicable, valid cross-platform buffering technique: The sausage network buffer for measuring food and physical activity built environments

    Directory of Open Access Journals (Sweden)

    Forsyth Ann

    2012-07-01

    Full Text Available Abstract Background Obesity researchers increasingly use geographic information systems to measure exposure and access in neighborhood food and physical activity environments. This paper proposes a network buffering approach, the “sausage” buffer. This method can be consistently and easily replicated across software versions and platforms, avoiding problems with proprietary systems that use different approaches in creating such buffers. Methods In this paper, we describe how the sausage buffering approach was developed to be repeatable across platforms and places. We also examine how the sausage buffer compares with existing alternatives in terms of buffer size and shape, measurements of the food and physical activity environments, and associations between environmental features and health-related behaviors. We test the proposed buffering approach using data from EAT 2010 (Eating and Activity in Teens, a study examining multi-level factors associated with eating, physical activity, and weight status in adolescents (n = 2,724 in the Minneapolis/St. Paul metropolitan area of Minnesota. Results Results show that the sausage buffer is comparable in area to the classic ArcView 3.3 network buffer particularly for larger buffer sizes. It obtains similar results to other buffering techniques when measuring variables associated with the food and physical activity environments and when measuring the correlations between such variables and outcomes such as physical activity and food purchases. Conclusions Findings from various tests in the current study show that researchers can obtain results using sausage buffers that are similar to results they would obtain by using other buffering techniques. However, unlike proprietary buffering techniques, the sausage buffer approach can be replicated across software programs and versions, allowing more independence of research from specific software.

  1. Experimental studies of buffer gap filling with artificial wetting

    Energy Technology Data Exchange (ETDEWEB)

    Holt, E.; Loeija, M.; Fortino, S.; Marjavaara, P. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2014-02-15

    The purpose of this work was to continue investigates on the swelling behaviour of artificially wetted highly compacted bentonite buffer blocks used in deposition holes for nuclear waste containment. The target was to study how filling the gap between the buffer block and deposition hole with wetted materials could create homogeneous and rapid swelling pressure. It is expected that the thermal, mechanical, chemical and hydraulic properties of the whole deposition system would be better when the bentonite-rock gap is closed with a uniform material. In practice, it is desirable that the bentonite material has a volume increase sufficient enough to create pressure against the rock surface. Uniform bentonite buffer swelling into the gap would prevent rock spalling while lowering the risks of bentonite piping and erosion due to potential water flow. In this work bentonite blocks were confined in a test chamber and bentonite material was added to the gap with additional artificial wetting to induce swelling. The resulting gap material and buffer bentonite generated swelling pressure in both the radial and vertical directions which was measured over time. Eighteen different test scenarios were investigated, including: variation of gap size, use of three different pellet types, use of three different bentonite slurry fillings, use of groundwater compared to tap water, and uniaxial compared to isostatic buffer blocks. After the wetting tests, material properties of the swollen buffer were measured, including measurements of moisture content, SHORE hardness, and density. This study also had a portion on 2D modelling of the bentonite swelling during the early ages, with either pellets or water added to the gap. Results from earlier studies were used to establish the models, which were then verified with the current experiments for time of developing swelling pressure. The results of this work showed that the use of gap filling bentonite material combined with artificial

  2. Experimental studies of buffer gap filling with artificial wetting

    International Nuclear Information System (INIS)

    The purpose of this work was to continue investigates on the swelling behaviour of artificially wetted highly compacted bentonite buffer blocks used in deposition holes for nuclear waste containment. The target was to study how filling the gap between the buffer block and deposition hole with wetted materials could create homogeneous and rapid swelling pressure. It is expected that the thermal, mechanical, chemical and hydraulic properties of the whole deposition system would be better when the bentonite-rock gap is closed with a uniform material. In practice, it is desirable that the bentonite material has a volume increase sufficient enough to create pressure against the rock surface. Uniform bentonite buffer swelling into the gap would prevent rock spalling while lowering the risks of bentonite piping and erosion due to potential water flow. In this work bentonite blocks were confined in a test chamber and bentonite material was added to the gap with additional artificial wetting to induce swelling. The resulting gap material and buffer bentonite generated swelling pressure in both the radial and vertical directions which was measured over time. Eighteen different test scenarios were investigated, including: variation of gap size, use of three different pellet types, use of three different bentonite slurry fillings, use of groundwater compared to tap water, and uniaxial compared to isostatic buffer blocks. After the wetting tests, material properties of the swollen buffer were measured, including measurements of moisture content, SHORE hardness, and density. This study also had a portion on 2D modelling of the bentonite swelling during the early ages, with either pellets or water added to the gap. Results from earlier studies were used to establish the models, which were then verified with the current experiments for time of developing swelling pressure. The results of this work showed that the use of gap filling bentonite material combined with artificial

  3. Chromatographic transport of alkaline buffers through reservoir rock

    International Nuclear Information System (INIS)

    Use of relatively low-pH alkaline buffers, such as sodium carbonate or sodium silicate, is explored as a means for overcoming sodium/hydrogen ion-exchange delay in alkaline waterflooding. A local-equilibrium chromatographic model is outlined to describe the concentration velocities for injection of alkaline buffers into a linear porous medium that exhibits reversible sodium/hydrogen exchange. The theory predicts a buffer ion-exchange wave that is substantially faster than that for equivalent-pH sodium hydroxide solutions. New experimental displacement data are presented for NaOH over a pH range from 11 to 13 and for 0.1, 0.5, and 1.0 wt% Na/sub 2/CO/sub 3/ flowing through a 1 wt% NaCl brine saturated Berea sandstone core at 500C [1220F]. To permit a complete description of the system, column effluent concentrations are measured for sodium ions, hydroxide ions, H/sup 3/-tagged water, and /sup 14/C-tagged carbonate. The experiments confirm that Na/sub 2/CO/sub 3/ propagates through the Berea sand at a higher rate than NaOH. For example, at pH=11.4, Na/sub 2/CO/sub 3/ migrates with a velocity that is 3.5 times faster than NaOH. Comparison of experiment with the ion-exchange chromatography theory shows good agreement. The authors successfully model the concentration histories of tritium-labeled water, total carbon, sodium, and hydroxide, all with no adjustable parameters. This work establishes with both theory and experiment that buffered alkali significantly increases the propagation speed of hydroxide in reservoir sands in comparison with unbuffered alkali at equivalent sodium and hydroxide concentrations. Because lower-pH buffered alkali can also protect against rock dissolution loss, the validated reduction of buffer ion-exchange lag considerably improves the promise of the alkaline flooding process for field application

  4. Ultrasonic monitoring of material processing using clad buffer rod sensors

    Science.gov (United States)

    Ramos Franca, Demartonne

    Ultrasonic sensors and techniques are developed for in-line monitoring of polymer extrusion, cleanliness of molten metals and liquid flow speed at elevated temperature. Pulse-echo mode is used for the first two processes, while the through-transmission mode is applied in the third one. The ultrasonic probe consists of high performance clad buffer rods with different dimensions to thermally isolate the commercial ultrasonic transducer from materials at high temperature. The clad buffer rods are made of steel, polymer and ceramic. Steel clad buffer rods are introduced for in-line monitoring of polymer extrusion processes. Owing to its superior performance in pulse-echo mode, for the first time such a probe is installed and performs ultrasonic monitoring in the die of a co-extrusion machine and in the barrel section of a twin-screw extruder. It can reveal a variety of information relevant to process parameters, such as polymer layer thickness, interface location and adhesion quality, stability, or polymer composition change. For the ultrasonic monitoring of polymer processes, probes with acoustic impedance that matches that of the processed polymer may offer certain advantages such as quantitative viscoelastic evaluation; thus high temperature polymer clad buffer rods, in particular PEEK, are developed. It is demonstrated that this new probe exhibits unique advantages for in-line monitoring of the cure of epoxies and polymer extrusion process. Long steel clad buffer rods with a spherical focus lens machined at the probing end are proposed for cleanliness evaluation of molten metals. The potential of this focusing probe is demonstrated by means of high-resolution imaging and particles detection in molten zinc at temperatures higher than 600°C, using a single probe operated at pulse-echo mode. A contrapropagating ultrasonic flowmeter employing steel clad buffer rods is devised to operate at high temperature. It is demonstrated that these rods guide ultrasonic signals

  5. 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.

  6. Influence of seawater on swelling characteristics of bentonite buffer material

    International Nuclear Information System (INIS)

    High-level-radioactive-waste disposal facility can be built on the coastal area. One reason is that transportation of the wastes is easy. Groundwater in the coastal zone which flows into disposal pit contains large amount of seawater salts. So, it is important to investigate the influence of seawater on bentonite buffer material which is one of the Barrier materials in the nuclear disposal facility. The purpose of this study is to investigate the influence of artificial seawater on swelling pressure and swelling deformation characteristics of five typical kinds of bentonites. Various factors, such as density, montmorillonite contents, sort of exchangeable-cation of the bentonite have been investigated. This experimental works clarified the some factors for which the influence of artificial sea water on swelling characteristics of bentonite depends. Based on experimental results, a specification for the buffer material which can overcome the influence of seawater was defined. (author)

  7. Increasing chemical efficiency by mixing different buffer gases on COIL

    Institute of Scientific and Technical Information of China (English)

    XuMingxiu; Sang Fengting; ChenFang; FangBenjie; JinYuqi

    2011-01-01

    To improve the output power and chemical efficiency,a new method is put forward,which requires no notable change in the configurations and uses different gases as buffer gas.Some experiments are done on chemical oxygen-iodine laser (COIL) with an 11.7 cm gain length.When N2,Ar and CO2 are used as the primary and secondary buffer gases,change of the average molecular weight promotes the mixing between the primary and secondary gases.Experimental results confirm the possibility of improving the chemical efficiency.When N2 is used as the primary gas and Ar as the secondary gas,the highest output power and chemical efficiency are obtained as 3.09 kW and 30.2%.

  8. Substrate dependent buffer-layer assisted growth of nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Honolka, Jan; Sessi, Violetta; Hertenberger, Simon; Kern, Klaus [Max-Planck Institute for Solid State Research, Stuttgart (Germany); Zhang, Jian [Max-Planck Institute for Solid State Research, Stuttgart (Germany); School of Material Science and Engineering, Hebei University of Technology, TianJin (China); Enders, Axel [Department of Physics and Astronomy and NCMN, University of Nebraska, Lincoln, Nebraska (United States)

    2010-05-15

    The role of the substrate on the morphology of nanometer size clusters fabricated by buffer layer assisted growth (BLAG) was studied using scanning tunneling microscopy. Clusters of Fe and Co were deposited on Ag(111), Cu(100), Rh(111), and Pt(111) surfaces using identical BLAG parameters, which are temperature, as well as metal and buffer layer coverage. Semi-hemispherical clusters are found on Ag(111) and Cu(100), while flat monolayer high islands are observed on Rh(111) and Pt(111) due to complete wetting. The results of this study are in agreement with the common notion that BLAG is useful to deposit clusters of virtually any material on any substrate, however, the shape, size, and lateral distribution of the resulting clusters depend strongly on the substrate surface free energy and diffusion processes. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Moisture buffer value: A comprehensive analysis of essential parameters

    DEFF Research Database (Denmark)

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

    2006-01-01

    There is an increasing focus on the possibilities of utilizing the absorptive ability of porous materials to create passive control of relative humidity (RH) variations in the indoor air.This has led to the need for determination of a newparameter that can be used for characterization of materials...... moisture buffer phenomenon. In the experiments the material samples were exposed to a sudden change in the RH of the ambient air which were either consecutive absorption and desorption steps or periodically varying cyclic steps....... determination of the moisture buffer value of building materials. Special focus is given to the significance of e.g. the equilibrium state, the step size in the RH and whether one is studying absorption or desorption steps. In addition, the paper summarizes shortly the experience until now of studying the...

  10. Buffered coscheduling for parallel programming and enhanced fault tolerance

    Science.gov (United States)

    Petrini, Fabrizio; Feng, Wu-chun

    2006-01-31

    A computer implemented method schedules processor jobs on a network of parallel machine processors or distributed system processors. Control information communications generated by each process performed by each processor during a defined time interval is accumulated in buffers, where adjacent time intervals are separated by strobe intervals for a global exchange of control information. A global exchange of the control information communications at the end of each defined time interval is performed during an intervening strobe interval so that each processor is informed by all of the other processors of the number of incoming jobs to be received by each processor in a subsequent time interval. The buffered coscheduling method of this invention also enhances the fault tolerance of a network of parallel machine processors or distributed system processors

  11. Electrokinetic determination of the buffer capacity of Andisols.

    Science.gov (United States)

    Vázquez, Mario V; Hernández-Luis, Felipe; Benjumea, Dora; Grandoso, Domingo; Lemus, Mercedes; Arbelo, Carmen D

    2007-05-25

    Among methods which involve the flow of electric current, the electro-remediation techniques have shown useful both for the removal of polluting species, and for obtaining a series of parameters in relatively laboratory simple experiments which can be used to characterize soils. This technique was applied in the present study to obtain experimental results with two soils from Tenerife. The capacity of the method as methodology for the measurement of the buffering capacity of these soils during electrokinetic experiments was analyzed. The results obtained on electrokinetic determination of buffer capacity correlated quite well with behaviour observed in the pH curves. The technique was promising for soil description primarily because important information could be obtained in shorter time periods than those required when using routine laboratory methods of soil analysis. PMID:17320934

  12. 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...... 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...... suggested protocols for the simple and fast measurement of the moisture buffer potential of interior elements allow qualitative assessment, none of these are currently dependable for a wide range of moisture production regimes. In response to these flaws, this paper introduces the production...

  13. Indicators used in setting the countercyclical capital buffer

    OpenAIRE

    Kalatie, Simo; Laakkonen, Helinä; Tölö, Eero

    2015-01-01

    According to EU legislation, the national authorities should use the principle of 'guided discretion' in setting the countercyclical capital buffer (CCB), which increases banks' resilience against systemic risk associated with periods of excessive credit growth. This means that the decision should be based on signals from a pre-determined set of early warning indicators, but that there should also be room for discretion, as there is always uncertainty associated with the use of early warning ...

  14. Separated Control and Data Stacks to Mitigate Buffer Overflow Exploits

    OpenAIRE

    Christopher Kugler; Tilo Müller

    2015-01-01

    Despite the fact that protection mechanisms like StackGuard, ASLR and NX are widespread, the development on new defense strategies against stack-based buffer overflows has not yet come to an end. In this article, we present a novel compiler-level protection called SCADS: Separated Control and Data Stacks that protects return addresses and saved frame pointers on a separate stack, called the control stack. In common computer programs, a single user mode stack is used to store control informati...

  15. Performance of buffer material under radiation and thermal conditions

    International Nuclear Information System (INIS)

    Bentonite is generally selected as backfill and buffer material for repositories in the world. Radiation and heat release is the intrinsic properties of high level radioactive waste. This paper made a preliminary research on foreign literature about performance of the engineering barrier material under radiation and at higher temperatures (e. g. above 100℃). As our current research is just budding in this area, we need to draw lessons from foreign experience and methods. (authors)

  16. Amelogenins as Potential Buffers during Secretory-stage Amelogenesis

    OpenAIRE

    Guo, J.; Lyaruu, D. M.; Y. Takano; Gibson, C W; DenBesten, P.K.; Bronckers, A.L.J.J.

    2015-01-01

    Amelogenins are the most abundant protein species in forming dental enamel, taken to regulate crystal shape and crystal growth. Unprotonated amelogenins can bind protons, suggesting that amelogenins could regulate the pH in enamel in situ. We hypothesized that without amelogenins the enamel would acidify unless ameloblasts were buffered by alternative ways. To investigate this, we measured the mineral and chloride content in incisor enamel of amelogenin-knockout (AmelX-/-) mice and determined...

  17. Focusing Light Beams To Improve Atomic-Vapor Optical Buffers

    Science.gov (United States)

    Strekalov, Dmitry; Matsko, Andrey; Savchenkov, Anatoliy

    2010-01-01

    Specially designed focusing of light beams has been proposed as a means of improving the performances of optical buffers based on cells containing hot atomic vapors (e.g., rubidium vapor). There is also a companion proposal to improve performance by use of incoherent optical pumping under suitable conditions. Regarding the proposal to use focusing: The utility of atomic-vapor optical buffers as optical storage and processing devices has been severely limited by nonuniform spatial distributions of intensity in optical beams, arising from absorption of the beams as they propagate in atomic-vapor cells. Such nonuniformity makes it impossible to optimize the physical conditions throughout a cell, thereby making it impossible to optimize the performance of the cell as an optical buffer. In practical terms simplified for the sake of brevity, "to optimize" as used here means to design the cell so as to maximize the group delay of an optical pulse while keeping the absorption and distortion of the pulse reasonably small. Regarding the proposal to use incoherent optical pumping: For reasons too complex to describe here, residual absorption of light is one of the main impediments to achievement of desirably long group delays in hot atomic vapors. The present proposal is directed toward suppressing residual absorption of light. The idea of improving the performance of slow-light optical buffers by use of incoherent pumping overlaps somewhat with the basic idea of Raman-based slow-light systems. However, prior studies of those systems did not quantitatively answer the question of whether the performance of an atomic vapor or other medium that exhibits electromagnetically induced transparency (EIT) with Raman gain is superior to that of a medium that exhibits EIT without Raman gain.

  18. Developing Suitable Buffers to Capture Transport Cycling Behavior

    OpenAIRE

    Madsen, Thomas; Schipperijn, Jasper; Christiansen, Lars Breum; Nielsen, Thomas Sick; Troelsen, Jens

    2014-01-01

    The association between neighborhood built environment and cycling has received considerable attention in health literature over the last two decades, but different neighborhood definitions have been used and it is unclear which one is most appropriate. Administrative or fixed residential spatial 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...

  19. BRAVO for many-server QED systems with finite buffers

    OpenAIRE

    Daley, DJ; Leeuwaarden, van, JSH Johan; Nazarathy, Y Yoni

    2015-01-01

    This paper demonstrates the occurrence of the feature called BRAVO (balancing reduces asymptotic variance of output) for the departure process of a finite-buffer Markovian many-server system in the QED (quality and efficiency-driven) heavy-traffic regime. The results are based on evaluating the limit of an equation for the asymptotic variance of death counts in finite birth-death processes.

  20. Energy Sharing for Multiple Sensor Nodes with Finite Buffers

    OpenAIRE

    Padakandla, Sindhu; J, Prabuchandran K.; Bhatnagar, Shalabh

    2015-01-01

    We consider the problem of finding optimal energy sharing policies that maximize the network performance of a system comprising of multiple sensor nodes and a single energy harvesting (EH) source. Sensor nodes periodically sense the random field and generate data, which is stored in the corresponding data queues. The EH source harnesses energy from ambient energy sources and the generated energy is stored in an energy buffer. Sensor nodes receive energy for data transmission from the EH sourc...

  1. Characteristics of strength for hydraulic fracturing of buffer material

    OpenAIRE

    Kobayashi, Akira; Yamamoto, Kiyohito; Momoki, Shohei

    2008-01-01

    The fundamental characteristics of strength for the hydraulic fracturing of highly compacted bentonite were studied. Firstly, the constant pressurize rate tests were carried out for the material having various specifications. Secondly, the cyclic pressurize test was carried out to examine the self-sealing function as a buffer material. Thirdly, the constant pressure test was carried out to observe the change in strength during seepage. The observed phenomena were analytically examined. As a r...

  2. Secure buffering in firm real-time database systems

    OpenAIRE

    George, Binto; Haritsa, Jayant R.

    2000-01-01

    Many real-time database applications arise in electronic financial services, safety-critical installations and military systems where enforcing security is crucial to the success of the enterprise. We investigate here the performance implications, in terms of killed transactions, of guaranteeing multi-level secrecy in a real-time database system supporting applications with firm deadlines. In particular, we focus on the buffer management aspects of this issue. Our main contributions are the f...

  3. Approach for Measuring Swelling Stress of Buffer Backfilling Material

    OpenAIRE

    Ming Zhang; Huyuan Zhang; Suli Cui; Lingyan Jia

    2012-01-01

    The characteristics of swelling stress of buffer backfilling material have been studied by forcebalance method and constant volume test method in this paper. The constant volume test apparatus was designed by the authors. Results show that swelling stress changing with time is a little different between the two methods. The value of swelling stress measured by constant volume test is more accurate; besides, uptaking water with time could also be monitored by constant volume test. The constant...

  4. Buffer zone water repellency: effects of the management practice

    OpenAIRE

    Rasa, Kimmo; Räty, Mari; Nikolenko, Olga; Horn, Rainer; Yli-Halla, Markku; Uusi-Kämppä, Jaana; Pietola, Liisa

    2006-01-01

    Water repellency index R was measured in a heavy clay and a sandy loam, used as arable land or buffer zone (BZ). Further, effect of management practise and ageing of BZs were studied. Water repellency was proved to be a common phenomenon on these soils. Harvesting and grazing increased water repellency as does ageing.Low water repellency is supposed to prevent preferential flows and provide evenly distributed water infiltration pattern through large soil volume, which favours nutrient retention.

  5. Current Controlled Current Differencing Buffered Amplifier: Implementation and Applications

    Directory of Open Access Journals (Sweden)

    Sudhanshu Maheshwari

    2004-01-01

    Full Text Available A new four terminal current-controlled active element is introduced, where parasitic resistances at two current input ports are controlled leading to the definition of current-controlled current differencing buffered amplifier. Bipolar implementation and as application current-mode band-pass filter circuits are proposed. Simulation results using real device parameters are included, which show device bandwidth of 35 MHz, low total harmonic distortions, and tuning over a wide current range.

  6. Effects of Terrestrial Buffer Zones on Amphibians on Golf Courses

    OpenAIRE

    Puglis, Holly J.; Boone, Michelle D.

    2012-01-01

    A major cause of amphibian declines worldwide is habitat destruction or alteration. Public green spaces, such as golf courses and parks, could serve as safe havens to curb the effects of habitat loss if managed in ways to bolster local amphibian communities. We reared larval Blanchard's cricket frogs (Acris blanchardi) and green frogs (Rana clamitans) in golf course ponds with and without 1 m terrestrial buffer zones, and released marked cricket frog metamorphs at the golf course ponds they w...

  7. A General Method for Defining and Structuring Buffer Management Problems

    OpenAIRE

    Lindholm, Anna; Forsman, Krister; Johnsson, Charlotta

    2010-01-01

    In an industrial plant, availability is an important factor since increased availability often gives an increase of final production, which in many cases means an increased profit for the company. The purpose of using buffer tanks is to increase the availability either by separating production units from each other or by minimizing flow variations. However, the methods for achieving this goal is not trivial, and depend on the specific characteristics of the problem. This paper contributes to ...

  8. Buffer layers on metal alloy substrates for superconducting tapes

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

    2004-06-29

    An article including a substrate, a layer of an inert oxide material upon the surface of the substrate, a layer of an amorphous oxide or oxynitride material upon the inert oxide material layer, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the amorphous oxide material layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected IC's of over 200 Amperes across a sample 1 cm wide.

  9. Cell Electrosensitization Exists Only in Certain Electroporation Buffers.

    Directory of Open Access Journals (Sweden)

    Janja Dermol

    Full Text Available Electroporation-induced cell sensitization was described as the occurrence of a delayed hypersensitivity to electric pulses caused by pretreating cells with electric pulses. It was achieved by increasing the duration of the electroporation treatment at the same cumulative energy input. It could be exploited in electroporation-based treatments such as electrochemotherapy and tissue ablation with irreversible electroporation. The mechanisms responsible for cell sensitization, however, have not yet been identified. We investigated cell sensitization dynamics in five different electroporation buffers. We split a pulse train into two trains varying the delay between them and measured the propidium uptake by fluorescence microscopy. By fitting the first-order model to the experimental results, we determined the uptake due to each train (i.e. the first and the second and the corresponding resealing constant. Cell sensitization was observed in the growth medium but not in other tested buffers. The effect of pulse repetition frequency, cell size change, cytoskeleton disruption and calcium influx do not adequately explain cell sensitization. Based on our results, we can conclude that cell sensitization is a sum of several processes and is buffer dependent. Further research is needed to determine its generality and to identify underlying mechanisms.

  10. Electroejaculation and semen buffer evaluation in the microbat Carollia perspicillata.

    Science.gov (United States)

    Fasel, Nicolas Jean; Helfenstein, Fabrice; Buff, Samuel; Richner, Heinz

    2015-03-15

    Scientific interests and conservation needs currently stress the necessity to better understanding bat reproductive biology. In this study, we present the first, safe, inexpensive, and reliable method to obtain sperm from a microbat species (Carollia perspicillata) by electroejaculation. This method revealed to be highly efficient (100% success rate). We obtained ejaculates composed of two characteristically different fractions. We compared three buffers and recommend using an Earle's balanced salt solution as a semen extender. Earle's balanced salt solution provided significant repeatable measure of swimming ability (intraclass correlation coefficient: 0.74, P < 0.01) and proportion of motile sperms (intraclass correlation coefficient: 0.08, P = 0.01) and allowed sperm to maintain optimal swimming capacity over time. None of the buffers could dissolve all the coagulated sperm. Although the trypsin buffer freed a larger fraction of spermatozoa in the ejaculate, it impaired swimming ability without improving motility, viability, and stamina. We thus argue that the sperm population analyzed with Earle's balanced salt solution is a representative of the ejaculate. Finally, we found that the mean sperm velocity of C perspicillata (78.8 μm/s) is lower than that predicted by regressing sperm velocity on relative testes mass, a proxy of sperm competition. The question as to whether C perspicillata is an outsider for sperm velocity, or whether bats evolved yet another unique mechanism to cope with sperm competition deserves more investigations. PMID:25541424

  11. Emission reduction by multipurpose buffer strips on arable fields.

    Science.gov (United States)

    Sloots, K; van der Vlies, A W

    2007-01-01

    In the area managed by Hollandse Delta, agriculture is under great pressure and the social awareness of the agricultural sector is increasing steadily. In recent years, a stand-still has been observed in water quality, in terms of agrochemicals, and concentrations even exceed the standard. To improve the waterquality a multi-purpose Field Margin Regulation was drafted for the Hoeksche Waard island in 2005. The regulation prescribes a crop-free strip, 3.5 m wide, alongside wet drainage ditches. The strip must be sown with mixtures of grasses, flowers or herbs. No crop protection chemicals or fertilizer may be used on the strips. A total length of approximately 200 km of buffer strip has now been laid. Besides reducing emissions, the buffer strips also stimulate natural pest control methods and encourage local tourism. Finally, the strips should lead to an improvement in the farmers' image. The regulation has proved to be successful. The buffer strips boosted both local tourism and the image of the agricultural sector. Above all, the strips provided a natural shield for emission to surface water, which will lead to an improvement of the water quality and raise the farmers' awareness of water quality and the environment. PMID:17711002

  12. Probabilistic Analysis of Buffer Starvation in Markovian Queues

    CERN Document Server

    Xu, Yuedong; El-Azouzi, Rachid; Haddad, Majed; Elayoubi, Salaheddine; Jimenez, Tania

    2011-01-01

    Our purpose in this paper is to obtain the exact distribution of the number of buffer starvations within a sequence of $N$ consecutive packet arrivals. The buffer is modeled as an M/M/1 queue, plus the consideration of bursty arrivals characterized by an interrupted Poisson process. When the buffer is empty, the service restarts after a certain amount of packets are prefetched. With this goal, we propose two approaches, one of which is based on Ballot theorem, and the other uses recursive equations. The Ballot theorem approach gives an explicit solution, but at the cost of the high complexity order in certain circumstances. The recursive approach, though not offering an explicit result, needs fewer computations. We further propose a fluid analysis of starvation probability on the file level, given the distribution of file size and the traffic intensity. The starvation probabilities of this paper have many potential applications. We apply them to optimize the quality of experience (QoE) of media streaming serv...

  13. 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.

  14. Analysis of Natural Buffer Systems and the Impact of Acid Rain

    Science.gov (United States)

    Powers, David C.; Yoder, Claude H.; Higgs, Andrew T.; Obley, Matt L.; Hess, Kenneth R.; Leber, Phyllis A.

    2005-01-01

    The environmental significance of acid rain on water systems of different buffer capacities is discussed. The most prevalent natural buffer system is created by the equilibrium between carbonate ions and carbon dioxide.

  15. A Temperature Independent pH (TIP) Buffer for Biomedical Biophysical Applications at Low Temperatures

    OpenAIRE

    Sieracki, Nathan A.; Hwang, Hee-Jung; Lee, Michelle K.; Garner, Dewain K.; Lu, Yi

    2007-01-01

    A temperature independent pH buffer has been develeloped from combination of buffers of opposite-sign temperature coefficients, and utility in low temperature spectroscopy and storage of pH sensitive compounds is demonstrated.

  16. Wheeler County Riparian Buffers; 2002-2003 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Potter, Judy; Homer, Will (Wheeler County Soil and Water Conservation District, John Day, OR)

    2004-02-01

    Problems Encountered During Contract Year--Wheeler County residents are mostly non participants when it comes to Farm Services programs. Results of the counties non participation is the rental rates are the lowest in the state. There is a government fear factor as well as an obvious distance limitation. The FSA office is nearly 150 mile roundtrip from two of the counties urban areas. I find myself not only selling the CREP-Riparian Buffer but also selling Farm Services in general. Training has been very limited. NRCS is obviously not designed around training and certification. They are an on-the-job training organization. It has caused a hesitation in my outreach program and a great deal of frustration. I feel my confidence will strengthen with the follow through of the current projects. The most evident problem has come to light as of late. The program is too expensive to implement. The planting is too intensive for a 12''-18'' rainfall area. I provide the potential landowner a spread sheet with the bonuses, the costs, and the final outcome. No matter the situation, CREP or CCRP, the landowner always balks at the cost. The program assumes the landowner has the capital to make the initial investment. For example, project No.2 is going to be a minimum width buffer. It is approximately 3,000 ft long and 5.5 acres. The buffer for tree planting and fencing alone will result in a cost of nearly $13,000. With the water developments it nears $23,000. That is nearly 10% of a 250 mother-cow operating budget. Project No.1, the tree planting estimate is $45,000. This alone is nearly 25% of the same type of budget. I would greatly appreciate any help in finding a third party willing to put money to work covering the initial costs of the program, expecting reimbursement from Farm Services Agency. I believe this could create a powerful tool in buffering streams in Wheeler County. Outlook for Contract Year 2--I have been in this position now for 6 months. I am

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

    International Nuclear Information System (INIS)

    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)

  18. Grassed buffer strips for the control of nitrate leaching to surface waters in headwater catchments.

    OpenAIRE

    Leeds-Harrison, P.B.; Quinton, John N.; Walker, M J; Sanders, C. L.; Harrod, T.

    1999-01-01

    The use of riparian buffer strips is a possible strategy for controlling diffuse nitrate pollution of surface water in agricultural catchments. Data collected from paired buffered and unbuffered headwater catchments at three sites with conditions representative of much of the agricultural land in England and Wales, showed that grassed buffers did not substantially reduce nitrate–nitrogen concentrations entering the streams. Median nitrate–nitrogen levels observed in buffered catchments ranged...

  19. The importance of moisture buffering for indoor climate and energy conditions of buildings

    OpenAIRE

    Rode, Carsten; Grau, Karl

    2007-01-01

    A new Nordic test method specifies a test protocol for determination of the so-called Moisture Buffer Value (MBV) of building materials. But how important is moisture buffering to determine the indoor humidity condition of buildings? The paper will present the new MBV-definition. Although it is primarily a value meant to characterise the moisture buffer property of building materials, can it also be used as a calculation parameter in design of buildings? And how does moisture buffering compar...

  20. Modelling riparian buffers for water quality enhancement in the Karapiro catchment

    OpenAIRE

    Ramilan, Thiagarajah; Scrimgeour, Frank G.; Marsh, Dan

    2010-01-01

    The use of riparian land buffers is widely promoted as a method of mitigating the effects of sediment and nutrient runoff from intensive land use in New Zealand. Farmers receive advice and financial assistance from Regional Councils for activities such as establishment and planting of riparian buffers, but funding is limited. The effect of buffers on water quality goals varies across land types so the optimum size of riparian buffer width varies across farms. We build a stylised model to dete...

  1. INVESTIGATION ON THE MORPHOLOGY OF PRECIPITATED CHEMICALS FROM TE BUFFER ON SOLID SUBSTRATES

    OpenAIRE

    HUABIN WANG; LIJUAN ZHANG; FENG ZHANG; HONGJIE AN; SHIMOU CHEN; HAI LI; PENG WANG; XINYANG WANG; YANG WANG; HAIJUN YANG

    2007-01-01

    Buffer is often involved in the biological studies on a surface with the scanning probe microscopy and the remnant of the salts of buffer may affect the correct interpretation of the experimental results. However, the knowledge on the performance of chemicals of buffer on a substrate is still very poor. TE solution (Tris–HCl, NaCl, and ethylene diamine tetraacetic acid (EDTA)) is a widely used buffer in stocking biological molecules. Herein, we report the performance of the precipitated chemi...

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

    Directory of Open Access Journals (Sweden)

    Schmitt Bernhard M

    2005-03-01

    Full Text Available Abstract 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.

  3. An Optimal Lower Bound for Buffer Management in Multi-Queue Switches

    OpenAIRE

    Bienkowski, Marcin

    2010-01-01

    In the online packet buffering problem (also known as the unweighted FIFO variant of buffer management), we focus on a single network packet switching device with several input ports and one output port. This device forwards unit-size, unit-value packets from input ports to the output port. Buffers attached to input ports may accumulate incoming packets for later transmission; if they cannot accommodate all incoming packets, their excess is lost. A packet buffering algorithm has to choose fro...

  4. 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

    Biochar as ecologically clean and stable form of carbon has complex of physical and chemical properties which make it a potentially powerful soil amendment (Mutezo, 2013). Therefore during the last decade the biochar application as soil amendment has been a matter for a great number of investigations. For the ecological viewpoint the trend of decreasing of soil organic matter in European agricultural land is a major problem. Society is faced with the task to find possibilities to stabilize or increase soil organic matter content in soil and quality. The availability of different functional groups (e.g. carboxylic, phenolic, acidic, alcoholic, amine, amide) allows soil organic matter to buffer over a wide range of soil pH values (Krull et al. 2004). Therefore the loss of soil organic matter also reduces cation exchange capacity resulting in lower nutrient retention (Kimetu et al. 2008). Biochar can retain elements in soil directly through the negative charge that develops on its surfaces, and this negative charge can buffer acidity in the soil. There are lack of investigations about the effect of biochar to soil pH buffering properties, The aim of our investigation was to investigate the changes in soil pH buffer capacity in a result of addition of carbonizated material to temperate region soils. In the experiment different kind of softwood biochars, activated carbon and different soil types with various organic matter and pH were used. The study soils were Albeluvisols, Leptosols, Cambisols, Regosols and Histosols . In the experiment the series of the soil: biochar mixtures with the biochar content 0 to 100% were used. The times of equiliberation between solid and liquid phase were from 1 to 168 hours. The suspension of soil: biochar mixtures was titrated with HCl solution. The titration curves were established and pH buffer capacities were calculated for the pH interval from 3.0 to 10.0. The results demonstrate the dependence of pH buffer capacity from soil type

  5. 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...

  6. Impact of buffer type on streamside nutrient concentrations in Upper Big Walnut Creek, Ohio

    Science.gov (United States)

    The identification and assessment of conservation practices continues to be important for the protection of natural resources. Buffers, also referred to as filter strips, buffer strips, riparian buffers, or vegetative filters are one of the most common types of conservation practice installed in the...

  7. 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.

  8. Classification of Orthophotos to Identify Vegetative Buffer Strips to Update Existing Land Use Databases

    Science.gov (United States)

    Vegetative buffer strips (VBS) including grass buffer, forested buffer (FBS), among others, are important best management practices implemented in agricultural areas to control the movement of potential agricultural contaminants into water bodies. The importance of VBS has led the Natural Resource C...

  9. Dynamic model and performance analysis of landing buffer for bionic locust mechanism

    Science.gov (United States)

    Chen, Dian-Sheng; Zhang, Zi-Qiang; Chen, Ke-Wei

    2015-10-01

    The landing buffer is an important problem in the research on bionic locust jumping robots, and the different modes of landing and buffering can affect the dynamic performance of the buffering process significantly. Based on an experimental observation, the different modes of landing and buffering are determined, which include the different numbers of landing legs and different motion modes of legs in the buffering process. Then a bionic locust mechanism is established, and the springs are used to replace the leg muscles to achieve a buffering effect. To reveal the dynamic performance in the buffering process of the bionic locust mechanism, a dynamic model is established with different modes of landing and buffering. In particular, to analyze the buffering process conveniently, an equivalent vibration dynamic model of the bionic locust mechanism is proposed. Given the support forces of the ground to the leg links, which can be obtained from the dynamic model, the spring forces of the legs and the impact resistance of each leg are the important parameters affecting buffering performance, and evaluation principles for buffering performance are proposed according to the aforementioned parameters. Based on the dynamic model and these evaluation principles, the buffering performances are analyzed and compared in different modes of landing and buffering on a horizontal plane and an inclined plane. The results show that the mechanism with the ends of the legs sliding can obtain a better dynamic performance. This study offers primary theories for buffering dynamics and an evaluation of landing buffer performance, and it establishes a theoretical basis for studies and engineering applications.

  10. Dynamic model and performance analysis of landing buffer for bionic locust mechanism

    Science.gov (United States)

    Chen, Dian-Sheng; Zhang, Zi-Qiang; Chen, Ke-Wei

    2016-06-01

    The landing buffer is an important problem in the research on bionic locust jumping robots, and the different modes of landing and buffering can affect the dynamic performance of the buffering process significantly. Based on an experimental observation, the different modes of landing and buffering are determined, which include the different numbers of landing legs and different motion modes of legs in the buffering process. Then a bionic locust mechanism is established, and the springs are used to replace the leg muscles to achieve a buffering effect. To reveal the dynamic performance in the buffering process of the bionic locust mechanism, a dynamic model is established with different modes of landing and buffering. In particular, to analyze the buffering process conveniently, an equivalent vibration dynamic model of the bionic locust mechanism is proposed. Given the support forces of the ground to the leg links, which can be obtained from the dynamic model, the spring forces of the legs and the impact resistance of each leg are the important parameters affecting buffering performance, and evaluation principles for buffering performance are proposed according to the aforementioned parameters. Based on the dynamic model and these evaluation principles, the buffering performances are analyzed and compared in different modes of landing and buffering on a horizontal plane and an inclined plane. The results show that the mechanism with the ends of the legs sliding can obtain a better dynamic performance. This study offers primary theories for buffering dynamics and an evaluation of landing buffer performance, and it establishes a theoretical basis for studies and engineering applications.

  11. 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

  12. Widespread site-dependent buffering of human regulatory polymorphism.

    Directory of Open Access Journals (Sweden)

    Matthew T Maurano

    Full Text Available The average individual is expected to harbor thousands of variants within non-coding genomic regions involved in gene regulation. However, it is currently not possible to interpret reliably the functional consequences of genetic variation within any given transcription factor recognition sequence. To address this, we comprehensively analyzed heritable genome-wide binding patterns of a major sequence-specific regulator (CTCF in relation to genetic variability in binding site sequences across a multi-generational pedigree. We localized and quantified CTCF occupancy by ChIP-seq in 12 related and unrelated individuals spanning three generations, followed by comprehensive targeted resequencing of the entire CTCF-binding landscape across all individuals. We identified hundreds of variants with reproducible quantitative effects on CTCF occupancy (both positive and negative. While these effects paralleled protein-DNA recognition energetics when averaged, they were extensively buffered by striking local context dependencies. In the significant majority of cases buffering was complete, resulting in silent variants spanning every position within the DNA recognition interface irrespective of level of binding energy or evolutionary constraint. The prevalence of complex partial or complete buffering effects severely constrained the ability to predict reliably the impact of variation within any given binding site instance. Surprisingly, 40% of variants that increased CTCF occupancy occurred at positions of human-chimp divergence, challenging the expectation that the vast majority of functional regulatory variants should be deleterious. Our results suggest that, even in the presence of "perfect" genetic information afforded by resequencing and parallel studies in multiple related individuals, genomic site-specific prediction of the consequences of individual variation in regulatory DNA will require systematic coupling with empirical functional genomic

  13. DESIGN AND IMPLEMENTATION OF SINGLE-BUFFERED ROUTERS

    Institute of Scientific and Technical Information of China (English)

    Hu Ximing; Qu Jing; Wang Binqiang; Wu Jiangxing

    2007-01-01

    A Single-Buffered (SB) router is a router where only one stage of shared buffering is sand-wiched between two interconnects in comparison of a Combined Input and Output Queued (CIOQ)router where a central switch fabric is sandwiched between two stages of buffering. The notion of SB routers was firstly proposed by the High-Performance Networking Group (HPNG) of Stanford University, along with two promising designs of SB routers: one of which was Parallel Shared Memory (PSM) router and the other was Distributed Shared Memory (DSM) router. Admittedly, the work of HPNG deserved full credit, but all results presented by them appeared to relay on a Centralized Memory Management Algorithm (CMMA) which was essentially impractical because of the high processing and communication complexity. This paper attempts to make a scalable high-speed SB router completely practical by introducing a fully distributed architecture for managing the shared memory of SB routers. The resulting SB router is called as a Virtual Output and Input Queued (VOIQ) router. Furthermore, the scheme of VOIQ routers can not only eliminate the need for the CMMA scheduler, thus allowing a fully distributed implementation with low processing and communication complexity, but also provide QoS guarantees and efficiently support variable-length packets in this paper. In particular, the results of performance testing and the hardware implementation of our VOIQ-based router (NDSC(R) SR1880-TTM series) are illustrated at the end of this paper. The proposal of this paper is the first distributed scheme of how to design and implement SB routers publicized till now.

  14. 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.

  15. Assessment of buffer zones in a world heritage site

    DEFF Research Database (Denmark)

    Algreen-Ussing, Gregers

    2005-01-01

    Paper presented at International conference on traditional Tibetan architecture and murals conservation. From year to year, the nimber of historical areas designated as World Heritage Sites is increasing. The result is not only, that monuments and outstanding phenomenon's are due to restrictions...... assessing developing historical areas as buffer zones. Finally, I will point to the Principles for the Conservation of Heritage Sites in China, as exceptional carefully composed guidelines. The purpose of the first approach is to establish an assessment of the existing building culture in a given site...

  16. Non-Sticking of Helium Buffer Gas to Hydrocarbons

    CERN Document Server

    Croft, James F E

    2014-01-01

    Lifetimes of complexes formed during helium-hydrocarbon collisions at low temperature are estimated for symmetric top hydrocarbons. The lifetimes are obtained using a density-of-states approach. In general the lifetimes are less than 10-100 ns, and are found to decrease with increasing hydrocarbon size. This suggests that clustering will not limit precision spectroscopy in helium buffer gas experiments. Lifetimes are computed for noble-gas benzene collisions and are found to be in reasonable agreement with lifetimes obtained from classical trajectories as reported by Cui {\\it et al}.

  17. Kir4.1-mediated spatial buffering of K(+)

    DEFF Research Database (Denmark)

    Larsen, Brian Roland; MacAulay, Nanna

    2014-01-01

    (+) from the extracellular space by molecular mechanism(s), the identity of which have been a matter of controversy for over half a century. Kir4.1-mediated spatial buffering of K(+) has been promoted as a major contributor to K(+) removal although its quantitative and temporal contribution has remained...... undefined. We discuss the biophysical and experimental challenges regarding determination of the contribution of Kir4.1 to extracellular K(+) management during neuronal activity. It is concluded that 1) the geometry of the experimental preparation is crucial for detection of Kir4.1-mediated spatial...

  18. VLSI implementation of a fairness ATM buffer system

    DEFF Research Database (Denmark)

    Nielsen, J.V.; Dittmann, Lars; Madsen, Jens Kargaard;

    1996-01-01

    This paper presents a VLSI implementation of a resource allocation scheme, based on the concept of weighted fair queueing. The design can be used in asynchronous transfer mode (ATM) networks to ensure fairness and robustness. Weighted fair queueing is a scheduling and buffer management scheme...... that can provide a resource allocation policy and enforcement of this policy. It can be used in networks in order to provide defined allocation policies (fairness) and improve network robustness. The presented design illustrates how the theoretical weighted fair queueing model can be approximated...

  19. Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers

    Energy Technology Data Exchange (ETDEWEB)

    Engel, Jesse H. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Surendranath, Yogesh [Univ. of California, Berkeley, CA (United States); Alivisatos, Paul [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-07-20

    Semiconductor nanocrystal solids are attractive materials for active layers in next-generation optoelectronic devices; however, their efficient implementation has been impeded by the lack of precise control over dopant concentrations. Herein we demonstrate a chemical strategy for the controlled doping of nanocrystal solids under equilibrium conditions. Exposing lead selenide nanocrystal thin films to solutions containing varying proportions of decamethylferrocene and decamethylferrocenium incrementally and reversibly increased the carrier concentration in the solid by 2 orders of magnitude from their native values. This application of redox buffers for controlled doping provides a new method for the precise control of the majority carrier concentration in porous semiconductor thin films.

  20. Acid-induced changes of brain protein buffering

    OpenAIRE

    Kraig, Richard P.; Wagner, Robert J.

    1987-01-01

    Excessive cellular acidosis is thought to enhance destruction of brain from ischemia. Protein denaturation may contribute to such injury although the behavior of brain proteins to acidosis is poorly defined. As a first approach to detect acid-induced changes in brain proteins and to characterize buffer content, homogenates were acidified for 20 min (as low as pH 3.1), returned to baseline pH (6.9), and then titrated. Titration curves show a significant (P < 0.0001) and permanent increase in b...

  1. 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.

  2. Buffer planning for application-specific networks-on-chip design

    Institute of Scientific and Technical Information of China (English)

    YIN ShouYi; LIU LeiBo; WEI ShaoJun

    2009-01-01

    Networks-on-chip (NoC) is a promising communication architecture for next generation SoC. The size of buffer used In on-chip routers impacts the silicon area and power consumption of NoC dominantly. It is important to plan the total buffer-size and each muter buffer-allocation carefully for an efficient NoC design. In this paper, we propose two buffer planning algorithms for application-specific NoC design. More precisely, given the traffic parameters and performance constraints of target application, the proposed algorithms automatically determine minimal buffer budget and assign the buffer depth for each input channel in different routers. The experimental results show that the proposed algorithms can significantly reduce total buffer usage and guarantee the performance requirements.

  3. Matching phosphate and maleate buffer systems for dissolution of weak acids: Equivalence in terms of buffer capacity of bulk solution or surface pH?

    Science.gov (United States)

    Cristofoletti, Rodrigo; Dressman, Jennifer B

    2016-06-01

    The development of in vitro dissolution tests able to anticipate the in vivo fate of drug products has challenged pharmaceutical scientists over time, especially in the case of ionizable compounds. In the seminal model proposed by Mooney et al. thirty-five years ago, the pH at the solid-liquid interface (pH0) was identified as a key parameter in predicting dissolution rate. In the current work it is demonstrated that the in vitro dissolution of the weak acid ibuprofen in maleate and phosphate buffer systems is a function of the pH0, which in turn is affected by properties of the drug and the medium. The reported pH0 for ibuprofen dissolution in bicarbonate buffer, the predominant buffer species in the human small intestine under fasting conditions, can be achieved by reducing the phosphate buffer concentration to 5.0mM or the maleate buffer concentration to 2.2mM. Using this approach to identify the appropriate buffer/buffer capacity combination for in vitro experiments in FaSSIF-type media, it would be possible to increase the physiological relevance of this important biopharmaceutics tool. However, the necessity of monitoring and adjusting the bulk pH during the experiments carried out in 5.0mM phosphate or 2.2mM maleate buffers must also be taken into consideration. PMID:27032508

  4. Transient response of a thermal buffer: a study for ISABELLE

    International Nuclear Information System (INIS)

    Operation of the superconducting magnets in ISABELLE may necessitate rapid cooldown and warmup from ambient (300K) to liquid helium temperature (3K) to meet the requirements of the experimental program. Similarly, unprogrammed temperature excursions can also occur due to operator error or equipment malfunction. The coal bore tube of the magnets has a small mass relative to the more massive iron laminations and the stainless steel support tube. In addition the magnet coil, in thermal contact with the cold bore tube, has excellent heat transfer to the helium flowing through it compared to the iron mass. These two factors, mass and heat transfer, dictate that the cold bore tube will follow the temperature of the coolant more closely than the iron and hence substantial temperature gradients can exist. If the temperature difference between the coolant and the iron in the magnet exceeds 44K stress failure may occur to either the cold bore tube or the magnet dewar end cap. To preclude such failures from occuring at least two options are available. One method is to modify the magnet design by introducing flexibility between the bore tube and the end plate. Another is to introduce an insensitive thermal mass or buffer as has been suggested by Shutt, at the inlet of a sextant ahead of the first magnets. This paper describes the latter method, the design and transient response of a buffer during cooldown

  5. Buffer Capacity, Ecosystem Feedbacks, and Seawater Chemistry under Global Change

    Directory of Open Access Journals (Sweden)

    Robert J. Toonen

    2013-09-01

    Full Text Available Ocean acidification (OA results in reduced seawater pH and aragonite saturation state (Ωarag, but also reduced seawater buffer capacity. As buffer capacity decreases, diel variation in seawater chemistry increases. However, a variety of ecosystem feedbacks can modulate changes in both average seawater chemistry and diel seawater chemistry variation. Here we model these effects for a coastal, reef flat ecosystem. We show that an increase in offshore pCO2 and temperature (to 900 µatm and + 3 °C can increase diel pH variation by as much as a factor of 2.5 and can increase diel pCO2 variation by a factor of 4.6, depending on ecosystem feedbacks and seawater residence time. Importantly, these effects are different between day and night. With increasing seawater residence time and increasing feedback intensity, daytime seawater chemistry becomes more similar to present-day conditions while nighttime seawater chemistry becomes less similar to present-day conditions. Recent studies suggest that carbonate chemistry variation itself, independent of the average chemistry conditions, can have important effects on marine organisms and ecosystem processes. Better constraining ecosystem feedbacks under global change will improve projections of coastal water chemistry, but this study shows the importance of considering changes in both average carbonate chemistry and diel chemistry variation for organisms and ecosystems.

  6. Stability and Throughput of Buffered Aloha with Backoff

    CERN Document Server

    Lee, Tony T

    2008-01-01

    This paper studies the buffered Aloha with K-exponential backoff collision resolution algorithms. The buffered Aloha network is modeled as a multi-queue single-server system. We adopt a widely used approach in packet switching systems to decompose the multi-queue system into independent first-in-first-out (FIFO) queues, which are hinged together by the probability of success of head-of-line (HOL) packets. A unified method is devised to tackle the stability and throughput problems of K-exponential backoff with any cutoff phase K. For networks with a finite number of nodes, we show that the K-exponential backoff is stable if the retransmission factor is properly chosen from the stable region. The maximum stable throughput is derived and demonstrated via examples of geometric retransmission (K=1) and exponential backoff (K=infinity). For networks with an infinite number of nodes, we show that geometric retransmission is unstable, and the stable network throughput of exponential backoff can only be achieved at th...

  7. Advance in Vertical Buffered Electropolishing on Niobium for Particle Accelerators*

    Energy Technology Data Exchange (ETDEWEB)

    A.T. Wu, S. Jin, J.D. Mammosser, C.E. Reece, R.A. Rimmer,L. Lin, X.Y. Lu, K. Zhao

    2011-09-01

    Niobium (Nb) is the most popular material that has been employed for making superconducting radio frequency (SRF) cavities to be used in various particle accelerators over the last couple of decades. One of the most important steps in fabricating Nb SRF cavities is the final chemical removal of 150 {mu}m of Nb from the inner surfaces of the SRF cavities. This is usually done by either buffered chemical polishing (BCP) or electropolishing (EP). Recently a new Nb surface treatment technique called buffered electropolishing (BEP) has been developed at Jefferson Lab. It has been demonstrated that BEP can produce the smoothest surface finish on Nb ever reported in the literature while realizing a Nb removal rate as high as 10 {mu}m/min that is more than 25 and 5 times quicker than those of EP and BCP(112) respectively. In this contribution, recent advance in optimizing and understanding BEP treatment technique is reviewed. Latest results from RF measurements on BEP treated Nb single cell cavities by our unique vertical polishing system will be reported.

  8. HEAVY TRAFFIC LIMIT THEOREMS IN FLUID BUFFER MODELS

    Institute of Scientific and Technical Information of China (English)

    YIN Gang; ZHANG Hanqin

    2004-01-01

    A fluid buffer model with Markov modulated input-output rates is considered.When traffic intensity is near its critical value, the system is known as in heavy traffic.It is shown that a suitably scaled sequence of the equilibrium buffer contents has a weakor distributional limit under heavy traffic conditionsThis weak limit is a functional of adiffusion process determined by the Markov chain modulating the input and output rates.The first passage time of the reflected process is examinedIt is shown that the mean firstpassage time can be obtained via a solution of a Dirichlet problemThen the transitiondensity of the reflected process is derived by solving the Kolmogorov forward equation witha Neumann boundary conditionFurthermore, when the fast changing part of the generatorof the Markov chain is a constant matrix, the representation of the probability distributionof the reflected process is derivedUpper and lower bounds of the probability distributionare also obtained by means of asymptotic expansions of standard normal distribution.

  9. Buffer-Aided Relaying with Adaptive Link Selection

    CERN Document Server

    Zlatanov, Nikola; Popovski, Petar

    2012-01-01

    In this paper, we consider a simple network consisting of a source, a half-duplex decode-and-forward relay, and a destination. We propose a new relaying protocol employing adaptive link selection, i.e., in any given time slot, based on the channel state information of the source-relay and the relay-destination link a decision is made whether the source or the relay transmits. In order to avoid data loss at the relay, adaptive link selection requires the relay to be equipped with a buffer such that data can be queued until the relay-destination link is selected for transmission. We study both delay constrained and delay unconstrained transmission. For the delay unconstrained case, we characterize the optimal link selection policy, derive the corresponding throughput, and develop an optimal power allocation scheme. For the delay constrained case, we propose to starve the buffer of the relay by choosing the decision threshold of the link selection policy smaller than the optimal one and derive a corresponding up...

  10. The Effects of Acetate Buffer Concentration on Lysozyme Solubility

    Science.gov (United States)

    Forsythe, Elizabeth L.; Pusey, Marc L.

    1996-01-01

    The micro-solubility column technique was employed to systematically investigate the effects of buffer concentration on tetragonal lysozyme solubility. While keeping the NaCl concentrations constant at 2%, 3%, 4%, 5% and 7%, and the pH at 4.0, we have studied the solubility of tetragonal lysozyme over an acetate buffer concentration range of 0.01M to 0.5M as a function of temperature. The lysozyme solubility decreased with increasing acetate concentration from 0.01M to 0.1M. This decrease may simply be due to the net increase in solvent ionic strength. Increasing the acetate concentration beyond 0.1M resulted in an increase in the lysozyme solubility, which reached a peak at - 0.3M acetate concentration. This increase was believed to be due to the increased binding of acetate to the anionic binding sites of lysozyme, preventing their occupation by chloride. In keeping with the previously observed reversal of the Hoffmeister series for effectiveness of anions in crystallizing lysozyme, acetate would be a less effective precipitant than chloride. Further increasing the acetate concentration beyond 0.3M resulted in a subsequent gradual decrease in the lysozyme solubility at all NaCl concentrations.

  11. The effect of Cr buffer layer thickness on voltage generation of thin-film thermoelectric modules

    International Nuclear Information System (INIS)

    The effect of Cr buffer layer thickness on the open-circuit voltage generated by thin-film thermoelectric modules of Bi0.5Sb1.5Te3 (p-type) and Bi2Te2.7Se0.3 (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 Cr2Te3. 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 Cr2Te3 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)

  12. 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. PMID:24261406

  13. Thermo-hydro-mechanical tests of buffer material

    International Nuclear Information System (INIS)

    MX-80 bentonite is the reference clay material for the buffer component planned to be used in the deep geological repository for the disposal of spent nuclear fuel in Finland. The buffer presents complex thermo-hydro-mechanical behavior which is modeled with different constitutive models for heat flow, water flow and stress-strain evolution in the buffer. Thermo, hydro and mechanical models need parameters to evaluate the THM-behavior. These modeling parameters were determined by performing series of laboratory experiments as follows: Water retention curve tests were performed on compacted bentonite samples, encompassing a range of initial dry density values from 1397 to 1718 kg/m3 as the initial water content was around of 5-8 %. The water retention curve was determined by imposing different suctions to the samples and the suctions were then checked using capacitive hygrometer and chilled mirror psychrometer. Oedometer tests were performed on compacted bentonite samples, encompassing a range of initial dry density values from 1590 to 1750 kg/m3 as the initial water content was around of 6 %. Samples were saturated with tap water, 35 or 70 g/L salt solutions. Infiltration tests were performed on compacted unsaturated bentonite samples, encompassing a range of initial dry density values from 1400 to 1720 kg/m3 as the initial water content was approximately between 4-7 %. Samples were saturated with tap water, 0.87, 35 or 70 g/L salt solutions. Tortuosity tests were performed on bentonite samples, encompassing a range of dry density values from 1460 to 1750 kg/m3 and the degree of saturation varied between 33-93 %. Thermal conductivity tests were performed on compacted bentonite samples, encompassing a range of dry density values from 1545 to 1715 kg/m3 and the degree of saturation varied between 31-88 %. The measurement was performed using a thermal needle probe. The general trend of all analyzed parameters was as expected when dry density, water content, and

  14. Temperature buffer test. Hydro-mechanical and chemical/ mineralogical characterizations

    International Nuclear Information System (INIS)

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modeling) 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 Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the hydro-mechanical and chemical/mineralogical characterization program which was launched subsequent to the dismantling operation. The main goal has been to investigate if any significant differences could be observed between material from the field experiment and the reference material. The field samples were mainly taken from Ring 4 (located at the mid-section around the lower heater), in which the temperature in the innermost part reached 155 deg C. The following hydro-mechanical properties have been determined for the material (test technique within brackets): hydraulic conductivity (swelling pressure device), swelling pressure (swelling pressure device), unconfined compression strength (mechanical press), shear strength (triaxial cell) and retention properties (jar method). The following chemical/mineralogical properties (methods within brackets) were determined: anion analysis of water leachates (IC), chemical composition (ICP/AES+MS, EGA), cation exchange capacity (CEC, Cu-trien method) and exchangeable cations (exchange with NH4, ICPAES), mineralogical composition (XRD and FTIR), element distribution and microstructure (SEM and

  15. Activation of a Ca-bentonite as buffer material

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Swelling behavior is an important criterion in achieving the low-permeability sealing function of buffer material. A potential buffer material may be used for radioactive waste repository in Taiwan is a locally available clayey material known as Zhisin clay, which has been identified as a Ca-bentonite. Due to its Ca-based origin, Zhisin was found to exhibit swelling capacity much lower than that of Na-bentonite. To enhance the swelling potential of Zhisin clay, a cation exchange process by addition of Na2CO3 powder was introduced in this paper. The addition of Na2CO3 reagent to Zhisin clay, in a liquid phase, caused the precipitation of CaCO3 and thereby induced a replacement of Ca2+ ions by Na+ ions on the surface of bentonite. Characterization test conducted on Zhisin clay includes chemical analysis, cation exchange capacity, X-ray diffraction, and thermogravimetry (TG). Free-swelling test apparatus was developed according to International Society of Rock Mechanics recommendations. A series of free-swelling tests were conducted on untreated and activated specimens to characterize the effect of activation on the swelling capacity of Zhisin clay. Efforts were made to determine an optimum dosage for the activation, and to evaluate the aging effect. Also, the activated material was evaluated for its stability in various hydrothermal conditions for potential applications as buffer material in a repository. Experimental results show that Na2CO3-activated Zhisin clay is superior in swelling potential to untreated Zhisin clay. Also, there exists an optimum amount of activator in terms of improvements in the swelling capacity. A distinct time-swell relationship was discovered for activated Zhisin clay. The corresponding mechanism refers to exchange of cations and breakdown of quasi-crystal, which results in ion exchange hysteresis of Ca-bentonite. Due to the ion exchange hysteresis, activated bentonite shows a post

  16. Activation of a Ca-bentonite as buffer material

    Science.gov (United States)

    Huang, Wei-Hsing; Chen, Wen-Chuan

    2016-04-01

    Swelling behavior is an important criterion in achieving the low-permeability sealing function of buffer material. A potential buffer material may be used for radioactive waste repository in Taiwan is a locally available clayey material known as Zhisin clay, which has been identified as a Ca-bentonite. Due to its Ca-based origin, Zhisin was found to exhibit swelling capacity much lower than that of Na-bentonite. To enhance the swelling potential of Zhisin clay, a cation exchange process by addition of Na2CO3 powder was introduced in this paper. The addition of Na2CO3 reagent to Zhisin clay, in a liquid phase, caused the precipitation of CaCO3 and thereby induced a replacement of Ca2+ ions by Na+ ions on the surface of bentonite. Characterization test conducted on Zhisin clay includes chemical analysis, cation exchange capacity, X-ray diffraction, and thermogravimetry (TG). Free-swelling test apparatus was developed according to International Society of Rock Mechanics recommendations. A series of free-swelling tests were conducted on untreated and activated specimens to characterize the effect of activation on the swelling capacity of Zhisin clay. Efforts were made to determine an optimum dosage for the activation, and to evaluate the aging effect. Also, the activated material was evaluated for its stability in various hydrothermal conditions for potential applications as buffer material in a repository. Experimental results show that Na2CO3-activated Zhisin clay is superior in swelling potential to untreated Zhisin clay. Also, there exists an optimum amount of activator in terms of improvements in the swelling capacity. A distinct time-swell relationship was discovered for activated Zhisin clay. The corresponding mechanism refers to exchange of cations and breakdown of quasi-crystal, which results in ion exchange hysteresis of Ca-bentonite. Due to the ion exchange hysteresis, activated bentonite shows a post-rise time-swell relationship different than the sigmoid

  17. How much will evolution buffer changes in climate?

    Science.gov (United States)

    Franks, S. J.

    2007-12-01

    Current climate change is altering the phenology, or seasonal timing of reproduction and other life-history events, of many species. There is now evidence that at least some of these changes in phenology represent genetically- based evolution. Evolution may thus potentially serve as a buffer, allowing species to adapt to changes in climatic conditions. However, there are many constraints to evolution, including lack of genetic variation, antagonistic trait correlations, and physiological and developmental constraints. Furthermore, if changes in climate are extremely rapid and severe, many species may experience extinction rather than rapid evolution. I present recent empirical evidence for evolution following changes in climate, examine constraints to evolution, and ask if evolution can keep pace with rapid climate change. The empirical work focuses on the species Brassica rapa, which I show evolved earlier flowering time following several years of drought in Southern California.

  18. Estuarine acidification and minimum buffer zone—A conceptual study

    Science.gov (United States)

    Hu, Xinping; Cai, Wei-Jun

    2013-10-01

    This study uses a simulation method to explore how estuarine pH is affected by mixing between river water, anthropogenic CO2 enriched seawater, and by respiration. Three rivers with different levels of weathering products (Amazon, Mississippi, and St. Johns) are selected for this simulation. The results indicate that estuaries that receive low to moderate levels of weathering products (Amazon and St. Johns) exhibit a maximum pH decrease in the midsalinity region as a result of anthropogenic CO2 intrusion. This maximum pH decrease coincides with a previously unrecognized mid-salinity minimum buffer zone (MBZ). In addition, water column oxygen consumption can further depress pH for all simulated estuaries. We suggest that recognition of the estuarine MBZs may be important for studying estuarine calcifying organisms and pH-sensitive biogeochemical processes.

  19. Effect of freezing and thawing on compacted bentonite buffer performance

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Over the time scale of the lifecycle of the spent nuclear fuel repository at Olkiluoto, local conditions involving both permafrost and glacial climactic phases, possibly repeatedly, cannot be excluded. Permafrost typically occurs when cold and dry climate conditions prevail with no ice-sheet formation or during glaciation as sub-glacial permafrost. Permafrost is generally defined as ground (soil or rock) that remains at or below 0 deg. C for at least two consecutive years. The growth and development of permafrost to some depth of the geologic subsurface depends on a complex heat exchange process across the atmosphere/ground interface and on the geothermal heat flow. Due to the potential impact on hydraulic, mechanical, and chemical subsurface properties and conditions, permafrost penetration is of interest for the performance and safety assessment of a deep, geologic repository. Deleterious effects on porous soil material, resulting from freezing and thawing, are generally ascribed to the occurrence of ice formation. Of course exposure to permafrost does not necessarily imply the presence of ice in the affected material. Indeed the primary consequence of the confinement of water in small pores is a depression to lower temperature of the melting transition. However, when ice forms in porous material, there is a corresponding increase in volume and/or pressure depending on the particular confining stresses at hand and the permeability to water migration. If ice is not formed in the fully saturated buffer system, no increase in volume and/or pressure need be considered. If, on the other hand, ice does form, increased stress from the buffer on the canister and host rock will need to be taken into account. In order to evaluate the effect of freezing and thawing on compacted bentonite buffer performance a series of experiments were conducted using constant-volume swelling pressure cells as follows: - Pre- and post

  20. A FASTBUS buffered interconnect: what are the options

    International Nuclear Information System (INIS)

    FASTBUS was designed as a system comprised of multiple bus segments in order to increase system throughput by parallel processing. Segments can operate independently but may also be connected together when necessary to accomplish intersegment communications. Two methods of interconnecting these segments were envisioned from the beginning. The first to be implemented, the ''Segment Interconnect,'' (SI) required great care in the FASTBUS protocol design to make its operation possible. The SI interface is a generalized bus window, temporarily synchronizing two segments and electrically connecting them so that handshakes between actual master and slave propagate through the interconnect. The second method is called the ''Buffered Interconnect,'' because the data to be transferred is stored temporarily in the interface and there is no direct handshake between the originating master and eventual receiving slave

  1. Analysis of buffering process of control rod hydraulic absorber

    International Nuclear Information System (INIS)

    Control Rod Hydraulic Drive Mechanism(CRHDM) is a newly invented build-in control rod drive mechanism. Hydraulic absorber is the key part of this mechanism, and is used to cushion the control rod when the rod scrams. Thus, it prevents the control rod from being deformed and damaged. In this paper dynamics program ANSYS CFX is used to calculate all kinds of flow conditions in hydraulic absorber to obtain its hydraulic characteristics. Based on the flow resistance coefficients obtained from the simulation results, fluid mass and momentum equations were developed to get the trend of pressure change in the hydraulic cylinder and the displacement of the piston rod during the buffering process of the control rod. The results obtained in this paper indicate that the hydraulic absorber meets the design requirement. The work in this paper will be helpful for the design and optimization of the control rod hydraulic absorber. (author)

  2. Stability of resazurin in buffers and mammalian cell culture media

    DEFF Research Database (Denmark)

    Rasmussen, Eva; Nicolaisen, G.M.

    1999-01-01

    The utility of a ferricyanide/ferrocyanide system used in the AlamarBlue(TM) (Serotec, Oxford, UK) vital. dye to inhibit the reduction of resazurin by mammalian cell culture media is questioned. Resazurin was found to be relatively stable when dissolved in phosphate-buffered saline (PBS). The use...... of HEPES resulted in a huge immediate dye reduction, which was significantly enhanced by exposure to diffuse light from fluorescent tubes in the laboratory 8 h per day. The reduction of resazurin by various cell culture media was time and temperature dependent, and it was significantly enhanced by......'s nutrient mixture F-10 and F-12. Fetal calf serum (5-20%) slightly decreased resazurin reduction during the first 2 days of incubation. The reduction of resazurin by mammalian cell culture media do not appear to be problematic under normal culture conditions, and it is primarily dependent upon the presence...

  3. Long term mineralogical properties of bentonite/quartz buffer substance

    International Nuclear Information System (INIS)

    This report shows results from investigations concerning properties in bentonitebased buffersubstances which are suggested to be used when high level radioactive wastes from nuclear powerplants are to be stored finally. Recommended material characteristica of the bentonite to be used are summerized. In an attempt to find geological evidence for bentonite to loose its desireable properties there were no such findings at the temperatures, groundwater situations and pressures which are to be expected at the actual depositing depth (500 m) for a considerable period of time. Concerning biological activity and then specially the mobility and activity of bacteria the conclusion is that there will be little or no influence from them either there is bentonite-sand or compacted pure bentonite in the buffer mass

  4. Buffer Sizing in Wireless Networks: Challenges, Solutions, and Opportunities

    KAUST Repository

    Showail, Ahmad

    2016-04-01

    Buffer sizing is an important network configuration parameter that impacts the Quality of Service (QoS) characteristics of data traffic. With falling memory costs and the fallacy that \\'more is better\\', network devices are being overprovisioned with large bu ers. This may increase queueing delays experienced by a packet and subsequently impact stability of core protocols such as TCP. The problem has been studied extensively for wired networks. However, there is little work addressing the unique challenges of wireless environment such as time-varying channel capacity, variable packet inter-service time, and packet aggregation, among others. In this paper we discuss these challenges, classify the current state-of-the-art solutions, discuss their limitations, and provide directions for future research in the area.

  5. Biodiversity buffers pollination from changes in environmental conditions.

    Science.gov (United States)

    Brittain, Claire; Kremen, Claire; Klein, Alexandra-Maria

    2013-02-01

    A hypothesized underlying principle of the diversity-functioning relationship is that functional groups respond differently to environmental change. Over 3 years, we investigated how pollinator diversity contributes to the magnitude of pollination service through spatial complementarity and differential response to high winds in California almond orchards. We found honey bees preferentially visited the top sections of the tree. Where wild pollinators were present, they showed spatial complementarity to honey bees and visited the bottom tree sections more frequently. As wind speed increased, honey bees' spatial preference shifted toward the bottom tree sections. In high winds (>2.5 m s(-1) ), orchards with low pollinator diversity (honey bees only) received almost no flower visits. In orchards with high pollinator diversity, visitation decreased to a lesser extent as wild bee visitation was unaffected by high winds. Our results demonstrate how spatial complementarity in diverse communities can help buffer pollination services to environmental changes like wind speed. PMID:23504791

  6. Buffer modification in determination of fluoride using selective ion electrode

    International Nuclear Information System (INIS)

    Determination of Fluoride in the Lanonorm 1 as Standard Reference material for urine OOSA 52/53 was done by Fluoride Ion selective Electrode Preparation of TISB (Total Ionic Strength Adjustor Buffer) was modified with Sodium and Potassium Chloride Salt at the pH 5,3. Standard Solution had been made 2 ppb until 9.10 exp. 4 ppb F from NaF and KF salt. The pH of TISB was made 5.3 ISE Fluoride and Double junction Reference 3,5 M KCl in outer compartment had been Installed within Metrohm 654 Potentiometer for investigating potential. Best result sample with error 3,6 % was found by TISB Natrium which use KF as calibration standard solution. (author)

  7. Coupled behaviour of bentonite buffer results of PUSKURI project

    International Nuclear Information System (INIS)

    In the report main results form a KYT2010 programme's project Coupled behaviour of bentonite buffer (PUSKURI) are presented. In THC modelling, Aku Itaelae made and published his Master of Science Thesis. Itaelae was able to successfully model the LOT-experiment. Additionally, he also listed problems and development proposals for THC-modelling of bentonite buffer. VTT and Numerola created in collaboration a model coupling saturation, diffusion and cation exchange; the model was implemented and tested in Numerrin, COMSOL and TOUGHREACT. Petri Jussila's PhD THM-model was implemented into COMSOL to facilitate further development. At GTK, the mineralogical characterisation of bentonite was planned. The previous THM model (Jussila's model) including only small deformations was successfully generalized to finite deformations in way at least formally preserving the original formalism. It appears that the theory allows also a possibility to include finite plastic deformations in the theory. In order to measure the relevant mechanical properties of compacted bentonite, two different experiments, namely hydrostatic compression experiment and one-dimensional compression experiment were designed. In the hydrostatic compression experiment, a cylindrical sample of compacted bentonite covered with liquid rubber coating is placed in the sample chamber equipped with a piston. The same device was also used in one-dimensional compression experiment. X-ray microtomographic techniques were used in order to study the basic mechanisms of water transport in bentonite. The preliminary results indicate that in the present experimental set-up, water transport is dominated by a dispersive mechanism such as diffusion of vapour in gas phase or diffusion of water in solid phase. (orig.)

  8. Calcium buffer proteins are specific markers of human retinal neurons.

    Science.gov (United States)

    Kántor, Orsolya; Mezey, Szilvia; Adeghate, Jennifer; Naumann, Angela; Nitschke, Roland; Énzsöly, Anna; Szabó, Arnold; Lukáts, Ákos; Németh, János; Somogyvári, Zoltán; Völgyi, Béla

    2016-07-01

    Ca(2+)-buffer proteins (CaBPs) modulate the temporal and spatial characteristics of transient intracellular Ca(2+)-concentration changes in neurons in order to fine-tune the strength and duration of the output signal. CaBPs have been used as neurochemical markers to identify and trace neurons of several brain loci including the mammalian retina. The CaBP content of retinal neurons, however, varies between species and, thus, the results inferred from animal models cannot be utilised directly by clinical ophthalmologists. Moreover, the shortage of well-preserved human samples greatly impedes human retina studies at the cellular and network level. Our purpose has therefore been to examine the distribution of major CaBPs, including calretinin, calbindin-D28, parvalbumin and the recently discovered secretagogin in exceptionally well-preserved human retinal samples. Based on a combination of immunohistochemistry, Neurolucida tracing and Lucifer yellow injections, we have established a database in which the CaBP marker composition can be defined for morphologically identified cell types of the human retina. Hence, we describe the full CaBP make-up for a number of human retinal neurons, including HII horizontal cells, AII amacrine cells, type-1 tyrosine-hydroxylase-expressing amacrine cells and other lesser known neurons. We have also found a number of unidentified cells whose morphology remains to be characterised. We present several examples of the colocalisation of two or three CaBPs with slightly different subcellular distributions in the same cell strongly suggesting a compartment-specific division of labour of Ca(2+)-buffering by CaBPs. Our work thus provides a neurochemical framework for future ophthalmological studies and renders new information concerning the cellular and subcellular distribution of CaBPs for experimental neuroscience. PMID:26899253

  9. Stability of biodegradable waterborne polyurethane films in buffered saline solutions.

    Science.gov (United States)

    Lin, Ying Yi; Hung, Kun-Che; Hsu, Shan-Hui

    2015-01-01

    The stability of polyurethane (PU) is of critical importance for applications such as in coating industry or as biomaterials. To eliminate the environmental concerns on the synthesis of PU which involves the use of organic solvents, the aqueous-based or waterborne PU (WBPU) has been developed. WBPU, however, may be unstable in an electrolyte-rich environment. In this study, the authors reported the stability of biodegradable WBPU in the buffered saline solutions evaluated by atomic force microscopy (AFM). Various biodegradable WBPU films were prepared by spin coating on coverslip glass, with a thickness of ∼300 nm. The surface AFM images of poly(ε-caprolactone) (PCL) diol-based WBPU revealed nanoglobular structure. The same feature was observed when 20% molar of the PCL diol soft segment was replaced by polyethylene butylenes adipate diol. After hydration in buffered saline solutions for 24 h, the surface domains generally increased in sizes and became irregular in shape. On the other hand, when the soft segment was replaced by 20% poly(l-lactide) diol, a meshlike surface structure was demonstrated by AFM. When the latter WBPU was hydrated, the surface domains appeared to be disconnected. Results from the attenuated total reflectance infrared spectroscopy and x-ray photoelectron spectroscopy indicated that the surface chemistry of WBPU films was altered after hydration. These changes were probably associated with the neutralization of carboxylate by ions in the saline solutions, resulting in the rearrangements of soft and hard segments and causing instability of the WBPU. PMID:26296357

  10. Elastic strain relief in nitridated Ga metal buffer layers for epitaxial GaN growth

    International Nuclear Information System (INIS)

    Gallium nitride epitaxial layers were grown on sapphire by molecular-beam epitaxy using nitridated gallium metal films as buffer layers. The mechanical properties of the buffer layers were investigated and correlated with their chemical composition as determined by synchrotron radiation photoelectron spectroscopy. Biaxial tension experiments were performed by bending the substrates in a pressure cell designed for simultaneous photoluminescence measurements. The shift of the excitonic luminescence peak was used to determine the stress induced in the main GaN epilayer. The fraction of stress transferred from substrate to main layer was as low as 27% for samples grown on nitridated metal buffer layers, compared to nearly 100% for samples on conventional low-temperature GaN buffer layers. The efficiency of stress relief increased in proportion to the fraction of metallic Ga in the nitridated metal buffer layers. These findings suggest GaN films containing residual metallic Ga may serve as compliant buffer layers for heteroepitaxy

  11. DAMQ-Based Schemes for Efficiently Using the Buffer Spaces of a NoC Router

    CERN Document Server

    Jamali, Mohammad Ali Jabraeil

    2009-01-01

    In this paper we present high performance dynamically allocated multi-queue (DAMQ) buffer schemes for fault tolerance systems on chip applications that require an interconnection network. Two or four virtual channels shared the same buffer space. On the message switching layer, we make improvement to boost system performance when there are faults involved in the components communication. The proposed schemes are when a node or a physical channel is deemed as faulty, the previous hop node will terminate the buffer occupancy of messages destined to the failed link. The buffer usage decisions are made at switching layer without interactions with higher abstract layer, thus buffer space will be released to messages destined to other healthy nodes quickly. Therefore, the buffer space will be efficiently used in case fault occurs at some nodes.

  12. Capillary electrophoresis of proteins in buffers containing high concentrations of zwitterionic salts.

    Science.gov (United States)

    Bushey, M M; Jorgenson, J W

    1989-10-20

    A method for improving protein separations in capillary zone electrophoresis utilizing high concentrations of zwitterionic buffer additives was examined. Lysozyme and alpha-chymotrypsinogen A were used as test proteins in untreated fused-silica capillaries in buffers of pH ca. 7.0 and 9.0 The zwitterion-containing buffers were compared with buffers containing high ionic salt concentrations and a buffer containing a combination of high ionic salt and high zwitterion concentrations. Over 100,000 theoretical plates were obtained in less than 30 min. for both test proteins in a pH 7 buffer containing both trimethylglycine and potassium sulfate. The advantages and disadvantages of this technique compared with those of other methods used to prevent protein adsorption are discussed. PMID:2592485

  13. Influence of Si buffer layer on the giant magnetoresistance effect in Co/Cu/Co sandwiches

    Institute of Scientific and Technical Information of China (English)

    李冠雄; 沈鸿烈; 沈勤我; 李铁; 邹世昌

    2000-01-01

    The Co/Cu/Co sandwiches with a semiconductor Si buffer layer were prepared by high vacuum electron-beam evaporation. The influence of the Si buffer layer with different thickness on the giant magnetoresistance (GMR) effect in the Co/Cu/Co sandwiches was investigated. It was found that the GMR showed an obvious anisotropy when the thickness of Si buffer layer was larger than or equal to 0.9 nm, and that the GMR was basically isotropic with an Si buffer layer thinner than 0.9 nm. The anisotropic behavior of GMR can be ascribed to the in-plane magnetic anisotropy in the sandwiches. Due to the interdiffusion at the Si buffer/Co interface, a Co2Si interface layer with a good (301) texture formed and induced the in-plane magnetic anisotropy in the sandwiches. The dependence of the crystalline texture of the sandwiches on the thickness of Si buffer layer was also studied.

  14. Surface Water Protection by Productive Buffers:Landscape Impacts of Improved Agro-Ecosystem Service Delivery

    OpenAIRE

    Christen, Benjamin

    2011-01-01

    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 stud...

  15. Relationships between soil physicochemical, microbiological properties, and nutrient release in buffer soils compared to field soils.

    Science.gov (United States)

    Stutter, Marc I; Richards, Samia

    2012-01-01

    The retention of nutrients in narrow, vegetated riparian buffer strips (VBS) is uncertain and underlying processes are poorly understood. Evidence suggests that buffer soils are poor at retaining dissolved nutrients, especially phosphorus (P), necessitating management actions if P retention is not to be compromised. We sampled 19 buffer strips and adjacent arable field soils. Differences in nutrient retention between buffer and field soils were determined using a combined assay for release of dissolved P, N, and C forms and particulate P. We then explored these differences in relation to changes in soil bulk density (BD), moisture, organic matter by loss on ignition (OM), and altered microbial diversity using molecular fingerprinting (terminal restriction fragment length polymorphism [TRFLP]). Buffer soils had significantly greater soil OM (89% of sites), moisture content (95%), and water-soluble nutrient concentrations for dissolved organic C (80%), dissolved organic N (80%), dissolved organic P (55%), and soluble reactive P (70%). Buffer soils had consistently smaller bulk densities than field soils. Soil fine particle release was generally greater for field than buffer soils. Significantly smaller soil bulk density in buffer soils than in adjacent fields indicated increased porosity and infiltration in buffers. Bacterial, archaeal, and fungal communities showed altered diversity between the buffer and field soils, with significant relationships with soil BD, moisture, OM, and increased solubility of buffer nutrients. Current soil conditions in VBS appear to be leading to potentially enhanced nutrient leaching via increasing solubility of C, N, and P. Manipulating soil microbial conditions (by management of soil moisture, vegetation type, and cover) may provide options for increasing the buffer storage for key nutrients such as P without increasing leaching to adjacent streams. PMID:22370402

  16. Two-way interplays between capital buffers, credit and output: evidence from French banks

    OpenAIRE

    Coffinet, J.; COUDERT, V.; Pop, A.; POUVELLE, C.

    2011-01-01

    We assess the extent to which capital buffers (the capital banks hold in excess of the regulatory minimum) exacerbate rather than reduce the cyclical behavior of credit. We empirically study the relationships between output gap, capital buffers and loan growth with firm-level data for French banks over the period 1993—2009. Our findings reveal that bank capital buffers intensify the cyclical credit fluctuations arising from the output gap developments, all the more as better quality capital i...

  17. Macroprudential Policy, Countercyclical Bank Capital Buffers and Credit Supply: Evidence from the Spanish Dynamic Provisioning Experiments

    OpenAIRE

    Jiménez, G.; Ongena, S.; Peydro, J.L.; Saurina, J.

    2012-01-01

    Abstract: We analyze the impact of the countercyclical capital buffers held by banks on the supply of credit to firms and their subsequent performance. Countercyclical ‘dynamic’ provisioning that is unrelated to specific loan losses was introduced in Spain in 2000, and modified in 2005 and 2008. These policy experiments which entailed bank-specific shocks to capital buffers, combined with the financial crisis that shocked banks according to their available pre-crisis buffers, underpin our ide...

  18. Electrophoretic mobilities of cultured human embryonic kidney cells in various buffers

    Science.gov (United States)

    1985-01-01

    Data on the electrophoretic mobility distributions of cells in the new D-1 buffer and the interlaboratory standardization of urokinase assay methods are presented. A table of cell strains and recent data on cell dispersal methods are also included. It was decided that glycerol in A-1 electrophoretic mobility data on cultured human embryonic kidney cells subjected to electrophoresis in this buffer. The buffer composition is presented.

  19. Benchmarch results of a genetic algorithm for non-permutation flowshops using constrained buffers

    OpenAIRE

    Färber, Gerrit Hartmut; Coves Moreno, Anna Maria

    2006-01-01

    This paper presents the performance study of a Genetic Algorithm, for the special case of a mixed model non-permutation flowshop production line, where resequencing is permitted when stations have access to intermittent or centralized resequencing buffers. The access to the buffers is restricted by the number of available buffer places and the physical size of the products. Results from other authors are compared which presented results on permutation sequences [1] or which treat a problem si...

  20. OPTIMAL BUFFER ALLOCATION IN TANDEM CLOSED QUEUING NETWORK WITH MULTI SERVERS USING PSO

    OpenAIRE

    K.L.Narasimhamu; V.Venugopal Reddy; C.S.P.Rao

    2014-01-01

    Buffer Allocation Problem is an important research issue in manufacturing system design. Objective of this paper is to find optimum buffer allocation for closed queuing network with multi servers at each node. Sum of buffers in closed queuing network is constant. Attempt is made to find optimum number of pallets required to maximize throughput of manufacturing system which has pre specified space for allocating pallets. Expanded Mean Value Analysis is used to evaluate the perfo...

  1. Transient and Stationary Losses in a Finite-Buffer Queue with Batch Arrivals

    OpenAIRE

    Andrzej Chydzinski; Blazej Adamczyk

    2012-01-01

    We present an analysis of the number of losses, caused by the buffer overflows, in a finite-buffer queue with batch arrivals and autocorrelated interarrival times. Using the batch Markovian arrival process, the formulas for the average number of losses in a finite time interval and the stationary loss ratio are shown. In addition, several numerical examples are presented, including illustrations of the dependence of the number of losses on the average batch size, buffer size, system load, aut...

  2. Development and evaluation of acid-buffering bioadhesive vaginal tablet for mixed vaginal infections

    OpenAIRE

    Alam, Mohd Aftab; Ahmad, Farhan Jalees; KHAN, ZEENAT IQBAL; Khar, Roop Krishen; ALI, MUSHIR

    2007-01-01

    An acid-buffering bioadhesive vaginal tablet was developed for the treatment of genitourinary tract infections. From the bioadhesion experiment and release studies it was found that polycarbophil and sodium carboxymethylcellulose is a good combination for an acid-buffering bioadhesive vaginal tablet. Sodium monocitrate was used as a buffering agent to provide acidic pH (4.4), which is an attribute of a healthy vagina. The effervescent mixture (citric acid and sodium bicarbonate) along with a ...

  3. The in vivo Effect of Dietary Buffering Capacity on the Bifidogenic Activity of Human Milk Oligosaccharides

    OpenAIRE

    Romond, M. B.; Romond, C; BEERENS, H.; Bourlioux, P

    2011-01-01

    The buffering capacity of a milk diet is known to be involved in the control of a newborn's bifidobacterial flora. Other factors could modulate the bifidobacterial flora e.g. bifidus factors present in human milk, which are growth-promoting for Bifidobacterium bifidum. The aim of this study was to investigate in gnotobiotic mice the effects of human milk bifidus factors upon colonisation by bifidobacteria according to the dietary buffering capacity. A high buffering capacity diet encouraged t...

  4. Dynamic monitoring and control of software project effort based on an effort buffer

    OpenAIRE

    Junguang Zhang; Ruixia Shi; Estrella Diaz

    2015-01-01

    The improvement to the monitoring and control efficiency of software project effort is a challenge for project management research. We propose to overcome this challenge through the use of a model for the buffer determination and monitoring of software project effort. This software project effort buffer was originally determined on the basis of a risk management factor analysis with total consideration for project managers’ risk preference. The effort buffer was next allocated to different st...

  5. Buffer clustering policy for sequential production lines with deterministic processing times

    Directory of Open Access Journals (Sweden)

    Francesca Schuler

    2016-09-01

    Full Text Available A sequential production line is defined as a set of sequential operations within a factory or distribution center whereby entities undergo one or more processes to produce a final product. Sequential production lines may gain efficiencies such as increased throughput or reduced work in progress by utilizing specific configurations while maintaining the chronological order of operations. One problem identified by the authors via a case study is that, some of the configurations, such as work cell or U-shaped production lines that have groups of buffers, often increase the space utilization. Therefore, many facilities do not take advantage of the configuration efficiencies that a work cell or U-shaped production line provide. To solve this problem, the authors introduce the concept of a buffer cluster. The production line implemented with one or more buffer clusters maintains the throughput of the line, identical to that with dedicated buffers, but with the clusters reduces the buffer storage space. The paper derives a time based parametric model that determines the sizing of the buffer cluster, provides a reduced time space for which to search for the buffer cluster sizing, and determines an optimal buffer clustering policy that can be applied to any N-server, N+1 buffer sequential line configuration with deterministic processing time. This solution reduces the buffer storage space utilized while ensuring no overflows or underflows occur in the buffer. Furthermore, the paper demonstrates how the buffer clustering policy serves as an input into a facility layout tool that provides the optimal production line layout.

  6. Living on the edge : effectiveness of buffer strips in protecting biodiversity on boreal riparian forests

    OpenAIRE

    Hylander, Kristoffer

    2004-01-01

    The objective of this thesis is to evaluate the ecological consequences of buffer strip retention on riparian and terrestrial biodiversity. Earlier studies on forest buffer strips have evaluated their effectiveness in relation to water quality and aquatic biota. However, forests along streams are species rich habitats for many organism groups. Buffer strip management is assumed to be important also for protecting such species. Current approaches to biodiversity-oriented forest management prac...

  7. Kinetics of a single trapped ion in an ultracold buffer gas

    OpenAIRE

    Zipkes, Christoph; Ratschbacher, Lothar; Sias, Carlo; Köhl, Michael

    2010-01-01

    The immersion of a single ion confined by a radiofrequency trap in an ultracold atomic gas extends the concept of buffer gas cooling to a new temperature regime. The steady state energy distribution of the ion is determined by its kinetics in the radiofrequency field rather than the temperature of the buffer gas. Moreover, the finite size of the ultracold gas facilitates the observation of back-action of the ion onto the buffer gas. We numerically investigate the system's properties depending...

  8. Applying critical chain buffer management theory in location-based management

    DEFF Research Database (Denmark)

    Büchmann-Slorup, Rolf

    2014-01-01

    Guidelines for prioritizing buffers on location-based management (LBM) projects are established through the use of critical chain theory (CCT). Buffer management theory in LBM has gained little attention from the research community. CCT builds on the assumption that each task is, either consciously...... prioritization in LBM that are based on critical chain buffer management theory....... the criticisms by CCT also apply to LBM projects, CCT is based on the critical path method, and the guidelines from CCT must be adapted to the criticality principle of LBM theory. Accordingly, the contribution to the body of knowledge of this article is guidelines of buffer placement and...

  9. Reducing interface recombination for Cu(In,Ga)Se2 by atomic layer deposited buffer layers

    International Nuclear Information System (INIS)

    Partial CuInGaSe2 (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnOx buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystalline II–VI systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide

  10. OPTIMAL BUFFER ALLOCATION IN TANDEM CLOSED QUEUING NETWORK WITH MULTI SERVERS USING PSO

    Directory of Open Access Journals (Sweden)

    K.L.Narasimhamu

    2014-11-01

    Full Text Available Buffer Allocation Problem is an important research issue in manufacturing system design. Objective of this paper is to find optimum buffer allocation for closed queuing network with multi servers at each node. Sum of buffers in closed queuing network is constant. Attempt is made to find optimum number of pallets required to maximize throughput of manufacturing system which has pre specified space for allocating pallets. Expanded Mean Value Analysis is used to evaluate the performance of closed queuing network. Particle Swarm Optimization is used as generative technique to optimize the buffer allocation. Numerical experiments are shown to explain effectiveness of procedure.

  11. Data on four criteria for targeting the placement of conservation buffers in agricultural landscapes.

    Science.gov (United States)

    Qiu, Zeyuan; Dosskey, Michael G; Kang, Yang

    2016-06-01

    Four criteria are generally used to prioritize agricultural lands for placing conservation buffers. The criteria include soil erodibility, hydrological sensitivity, wildlife habitat, and impervious surface rate that capture conservation buffers' benefits in reducing soil erosion, controlling runoff generation, enhancing wildlife habitat, and mitigating stormwater impacts, respectively. This article describes the data used to derive the values of those attributes and a scheme to classify the values in multi-criteria analysis of conservation buffer placement in "Choosing between alternative placement strategies for conservation buffers using borda count" [1]. PMID:27222843

  12. An Buffer Overflow Automatic Detection MethodBased on Operation Semantic

    Institute of Scientific and Technical Information of China (English)

    ZHAO Dong-fan; LIU Lei

    2005-01-01

    Buffer overflow is the most dangerous attack method that can be exploited. According to the statistics of Computer Emergency Readiness Team(CERT), buffer overflow accounts for 50% of the current software vulnerabilities, and this ratio is going up. Considering a subset of C language, Mini C, this paper presents an abstract machine model that can realize buffer overflow detection, which is based on operation semantic. Thus the research on buffer overflow detection can be built on strict descriptions of operation semantic. Not only the correctness can be assured, but also the system can be realized and extended easily.

  13. Formation of van der Waals molecules in buffer gas cooled magnetic traps

    CERN Document Server

    Brahms, N; Zhang, P; los, J K; Sadeghpour, H R; Dalgarno, A; Doyle, J M; Walker, T G

    2010-01-01

    We show that a large class of helium-containing cold polar molecules form readily in a cryogenic buffer gas, achieving densities as high as 10^12 cm^-3. We explore the spin relaxation of these molecules in buffer gas loaded magnetic traps, and identify a loss mechanism based on Landau-Zener transitions arising from the anisotropic hyperfine interaction. Our results show that the recently observed strong T^6 thermal dependence of spin change in buffer gas trapped silver (Ag) is accounted for by the formation and spin change of AgHe, thus providing evidence for molecular formation in a buffer gas trap.

  14. The dual role of lakes as buffers and amplifiers of dissolved organic matter temporal dynamics: Buffering transport and amplifying transformation

    Science.gov (United States)

    Ejarque, Elisabet; Schelker, Jakob; Khan, Samiullah; Hollaus, Lisa-Maria; Steniczka, Gertraud; Kainz, Martin; Battin, Tom

    2016-04-01

    Lakes that disrupt the flow of water and its constituents within the fluvial continuum can modify the downstream dynamics of dissolved organic matter (DOM). Potential causes of this change may include the hydrological buffering capacity of lakes relative to streams and rivers and the amplification of biotic processes. To test this hypothesis, we measured DOM quantity and quality at the inflow and outflow of sub-alpine Lake Lunz (Lower Austria) during one year. DOM quality was characterised using optical metrics indicative of the humic-like composition (fluorescence peak C), humification (HIX), and aromaticity (SUVA) degree, predominance of autochthonous components (BIX), and average molecular weight (E2:E3). Total annual variability was found to be lower in the outflow compared with the inflow (SDout:SDin 1). This was due to the large seasonal variability in the outflow, which contrasted with a reduced temporal dynamics in the inflow. Combined, this created a shift from similar inflow-outflow DOM characteristics during winter, to uncoupled DOM characteristics during summer. This uncoupling consisted in a higher signal of the autotrophic origin of DOM, a lower average molecular weight, as well as a lower aromatic and humic-like content in the outflow. Overall, these results highlight the role of the Lake Lunz as a DOC source and as a buffer of hydrological pulses of DOC export. Moreover, results emphasise the capacity of the lake to amplify the seasonal variability of DOM quality, creating a maximum uncoupling between the inflow and the outflow during the months of increased biotic processing in the lake.

  15. Effects of Riparian Buffer Vegetation and Width: A 12-Year Longitudinal Study.

    Science.gov (United States)

    King, S E; Osmond, D L; Smith, J; Burchell, M R; Dukes, M; Evans, R O; Knies, S; Kunickis, S

    2016-07-01

    Agricultural contributions of nitrogen are a serious concern for many water resources and have spurred the implementation of riparian buffer zones to reduce groundwater nitrate (NO). The optimum design for buffers is subject to debate, and there are few long-term studies. The objective of this project was to determine the effectiveness over time (12 yr) of buffer types (trees, switchgrass, fescue, native, and a control) and buffer widths (8 and 15 m) by measuring groundwater NO-N and dissolved organic carbon (DOC) trends. At the intermediate groundwater depth (1.5-2.1 m), NO-N reduction effectiveness was 2.5 times greater (46 vs. 16%) for the wider buffer, and, regardless of width, buffer effectiveness increased 0.62% yr. Buffer vegetative type was never statistically significant. In the deep-groundwater depth (2.1-3.5 m), there was no change in NO-N removal over time, although the statistical interaction of width and vegetative type indicated a wide range of removal rates (19-82%). The DOC concentrations were analyzed at the field/buffer and buffer/stream sampling locations. Depending on location position and groundwater sampling depth, DOC concentrations ranged from 1.6 to 2.8 mg L at Year 0 and increased at a rate of 0.13 to 0.18 mg L yr but always remained low (≤5.0 mg L). Greater DOC concentrations in the intermediate-depth groundwater did not increase NO-N removal; redox measurements indicated intermittent reduced soil conditions may have been limiting. This study suggests that riparian buffer width, not vegetation, is more important for NO-N removal in the middle coastal plain of North Carolina for a newly established buffer. PMID:27380072

  16. Effect of Oxide Buffer Layer on the Thermochromic Properties of VO2 Thin Films

    Science.gov (United States)

    Koo, Hyun; Xu, Lu; Ko, Kyeong-Eun; Ahn, Seunghyun; Chang, Se-Hong; Park, Chan

    2013-12-01

    VO2 thin films were deposited on soda lime glass substrates with ZnO, TiO2, SnO2, and CeO2 thin films applied as buffer layers between the VO2 films and the substrates in order to investigate the effect of buffer layer on the formation and the thermochromic properties of VO2 film. Buffer layers with thicknesses over 50 nm were found to affect the formation of VO2 film, which was confirmed by XRD spectra. By using ZnO, TiO2, and SnO2 buffer layers, monoclinic VO2 (VO2(M)) film was successfully fabricated on soda lime glass at 370 °C. On the contrary, films of VO2(B), which is known to have no phase transition near room temperature, were formed rather than VO2(M) when the film was deposited on CeO2 buffer layer at the same film deposition temperature. The excellent thermochromic properties of the films deposited on ZnO, TiO2, and SnO2 buffer layers were confirmed from the temperature dependence of electrical resistivity from room temperature to 80 °C. Especially, due to the tendency of ZnO thin film to grow with a high degree of preferred orientation on soda lime glass at low temperature, the VO2 film deposited on ZnO buffer layer exhibits the best thermochromic properties compared to those on other buffer layer materials used in this study. These results suggest that deposition of VO2 films on soda lime glass at low temperature with excellent thermochromic properties can be achieved by considering the buffer layer material having structural similarity with VO2. Moreover, the degree of crystallization of buffer layer is also related with that of VO2 film, and thus ZnO can be one of the most effective buffer layer materials.

  17. Development and Evaluation of a Riparian Buffer Mapping Tool

    Science.gov (United States)

    Milheim, Lesley E.; Claggett, Peter R.

    2008-01-01

    Land use and land cover within riparian areas greatly affect the conditions of adjacent water features. In particular, riparian forests provide many environmental benefits, including nutrient uptake, bank stabilization, steam shading, sediment trapping, aquatic and terrestrial habitat, and stream organic matter. In contrast, residential and commercial development and associated transportation infrastructure increase pollutant and nutrient loading and change the hydrologic characteristics of the landscape, thereby affecting both water quality and habitat. Restoring riparian areas is a popular and cost effective restoration technique to improve and protect water quality. Recognizing this, the Chesapeake Executive Council committed to restoring 10,000 miles of riparian forest buffers throughout the Chesapeake Bay watershed by the year 2010. In 2006, the Chesapeake Executive Council further committed to 'using the best available...tools to identify areas where retention and expansion of forests is most needed to protect water quality'. The Chesapeake Bay watershed encompasses 64,000 square miles, including portions of six States and Washington, D.C. Therefore, the interpretation of remotely sensed imagery provides the only effective technique for comprehensively evaluating riparian forest protection and restoration opportunities throughout the watershed. Although 30-meter-resolution land use and land cover data have proved useful on a regional scale, they have not been equally successful at providing the detail required for local-scale assessment of riparian area characteristics. Use of high-resolution imagery (HRI) provides sufficient detail for local-scale assessments, although at greater cost owing to the cost of the imagery and the skill and time required to process the data. To facilitate the use of HRI for monitoring the extent of riparian forest buffers, the U.S. Forest Service and the U.S. Geological Survey Eastern Geographic Science Center funded the

  18. Temperature buffer test. Hydro-mechanical and chemical/ mineralogical characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias; Olsson, Siv; Dueck, Ann; Nilsson, Ulf; Karnland, Ola [Clay Technology AB, Lund (Sweden); Kiviranta, Leena; Kumpulainen, Sirpa [BandTech Oy, Helsinki (Finland); Linden, Johan [Aabo Akademi, Aabo (Finland)

    2012-01-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modeling) 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 Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the hydro-mechanical and chemical/mineralogical characterization program which was launched subsequent to the dismantling operation. The main goal has been to investigate if any significant differences could be observed between material from the field experiment and the reference material. The field samples were mainly taken from Ring 4 (located at the mid-section around the lower heater), in which the temperature in the innermost part reached 155 deg C. The following hydro-mechanical properties have been determined for the material (test technique within brackets): hydraulic conductivity (swelling pressure device), swelling pressure (swelling pressure device), unconfined compression strength (mechanical press), shear strength (triaxial cell) and retention properties (jar method). The following chemical/mineralogical properties (methods within brackets) were determined: anion analysis of water leachates (IC), chemical composition (ICP/AES+MS, EGA), cation exchange capacity (CEC, Cu-trien method) and exchangeable cations (exchange with NH4, ICPAES), mineralogical composition (XRD and FTIR), element distribution and microstructure (SEM and

  19. Electrokinetic remediation of cobalt contaminated soil using ethanoic buffer

    International Nuclear Information System (INIS)

    After kaolin clay was artificially contaminated with Co2+ ion, the remediation characteristics were analyzed by the electrokinetic method. Ethanoic buffer was injected in the soil column and CH3COOH was continuously inputted to the cathode reservoir to restrain the pH increase. Since the pH of the cathode side of the soil column was 4.0 initially and increased to only 6.5 after remediation for 43.6 hours, precipitate, Co(OH)2, was not formed in the column. The effluent rate increased with the passage of time and Co2+ removal in the column at the initial time were mainly controlled by ion migration. 13.1% of the total amount of Co2+ in the soil column was removed in 10 hours, 46.8% of the total Co2+ in 20.8 hours, 71.7% of the total Co2+ in 30.1 hours, and 94.6% of the total Co2+ in 43.6 hours. Meanwhile, residual concentrations in the column calculated by the developed model were similar to those by experiment

  20. Modeling the hepatic arterial buffer response in the liver.

    Science.gov (United States)

    Ho, Harvey; Sorrell, Keagan; Bartlett, Adam; Hunter, Peter

    2013-08-01

    In this paper we present an electrical analog model for the hepatic arterial buffer response (HABR), an intrinsic regulation mechanism in the liver whereby the arterial flow counteracts the changes in portal venous flow. The model itself is a substantial simplification of a previously published model, with nonlinear arterial and portal resistors introduced to account for the dynamic HABR effects. We calibrate the baseline model using published hemodynamic data, and then perform a virtual portal occlusion simulation where the portal vein is half or fully occluded. The simulation results, which suggest that the increased arterial flow cannot fully compensate lost portal perfusion, are consistent with clinical reports and animal model findings. Since HABR functions in both the whole liver and liver graft after transplantation, we also simulate blood flow in a virtual right-lobe graft by adjusting the electronic component parameters in the electric circuit, and our model is able to reproduce the portal venous hyperperfusion and hepatic arterial hypoperfusion conditions due to the HABR effects. PMID:23157977

  1. Neutron electric dipole moment measurement with a buffer gas comagnetometer

    International Nuclear Information System (INIS)

    A neutron EDM measurement with a comagnetometer is discussed. For magnetometry, polarized xenon atoms are injected into a cylindrical cell where a cylindrically symmetric magnetic field and an electric field are applied for the EDM measurement. The geometric phase effect (GPE), which originates from particle motion in a magnetic field gradient, is analyzed in terms of the Dyson series. The motion of the xenon atom is largely suppressed because of a small mean free path. The field gradient is controlled by means of NMR measurements, where the false effect of Earth's rotation is removed. As a result, the GPE is reduced below 10−28e cm. -- Highlights: ► A method of high precision neutron EDM measurement is described. ► Geometric phase effects are discussed in terms of Dyson series. ► A magnetic field drift is compensated by means of a buffer gas magnetometer. ► Geometric phase effects are greatly suppressed. ► The systematic error is reduced by two orders of magnitude compared with before.

  2. Aggregation and adhesion of gold nanoparticles in phosphate buffered saline

    International Nuclear Information System (INIS)

    In applications in medicine and more specifically drug delivery, the dispersion stability of nanoparticles plays a significant role on their final performances. In this study, with the use of two laser technologies, dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA), we report a simple method to estimate the stability of nanoparticles dispersed in phosphate buffered saline (PBS). Stability has two features: (1) self-aggregation as the particles tend to stick to each other; (2) disappearance of particles as they adhere to surrounding substrate surfaces such as glass, metal, or polymer. By investigating the effects of sonication treatment and surface modification by five types of surfactants, including nonylphenol ethoxylate (NP9), polyvinyl pyrrolidone (PVP), human serum albumin (HSA), sodium dodecyl sulfate (SDS) and citrate ions on the dispersion stability, the varying self-aggregation and adhesion of gold nanoparticles dispersed in PBS are demonstrated. The results showed that PVP effectively prevented aggregation, while HSA exhibited the best performance in avoiding the adhesion of gold nanoparticle in PBS onto glass and metal. The simple principle of this method makes it a high potential to be applied to other nanoparticles, including virus particles, used in dispersing and processing.

  3. Aggregation and adhesion of gold nanoparticles in phosphate buffered saline

    Energy Technology Data Exchange (ETDEWEB)

    Du Shangfeng, E-mail: s.du@bham.ac.uk; Kendall, Kevin; Toloueinia, Panteha; Mehrabadi, Yasamin; Gupta, Gaurav; Newton, Jill [University of Birmingham, School of Chemical Engineering (United Kingdom)

    2012-03-15

    In applications in medicine and more specifically drug delivery, the dispersion stability of nanoparticles plays a significant role on their final performances. In this study, with the use of two laser technologies, dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA), we report a simple method to estimate the stability of nanoparticles dispersed in phosphate buffered saline (PBS). Stability has two features: (1) self-aggregation as the particles tend to stick to each other; (2) disappearance of particles as they adhere to surrounding substrate surfaces such as glass, metal, or polymer. By investigating the effects of sonication treatment and surface modification by five types of surfactants, including nonylphenol ethoxylate (NP9), polyvinyl pyrrolidone (PVP), human serum albumin (HSA), sodium dodecyl sulfate (SDS) and citrate ions on the dispersion stability, the varying self-aggregation and adhesion of gold nanoparticles dispersed in PBS are demonstrated. The results showed that PVP effectively prevented aggregation, while HSA exhibited the best performance in avoiding the adhesion of gold nanoparticle in PBS onto glass and metal. The simple principle of this method makes it a high potential to be applied to other nanoparticles, including virus particles, used in dispersing and processing.

  4. Collision relaxation in 13CH3F with buffers

    International Nuclear Information System (INIS)

    Technique of delayed optical nutations is investigated from the viewpoint of possibility to measure collision relaxation rates in molecular gas by application of levels Stark switching. The numerical analysis enabled us to define the range of experimental parameters, at which the dependence of the delayed nutation signal on the duration of the Stark pulse becomes pure exponential, providing simple measuring tools. Experiments were performed at rotation transition R(4,3) of vibration band 0 ↔ 1 ν3 of polar gas 13CH3F by levels Stark switching method in presence of CW radiation of CO2 laser operating at 9P(32) line. Both pure 13CH3F gas and its mixtures with atomic buffers He, Ne, Ar, Kr and non-polar molecular gases N2, and CO2 were studied. The experiments revealed that the relaxation cross-section increases with a mass of collision partner, but do not exceed the cross-section in pure 13CH3F

  5. A Dynamic Self-Adjusted Buffering Mechanism for Peer-to-Peer Real-Time Streaming

    Directory of Open Access Journals (Sweden)

    Jun-Li Kuo

    2011-05-01

    Full Text Available Multimedia live stream multicasting and on-line real-time applications are popular recently. Real-time multicast system can use peer-to-peer technology to keep stability and scalability without any additional support from the underneath network or a server. Our proposed scheme focuses on the mesh architecture of peer-to-peer live streaming system and experiments with the buffering mechanisms. We design the dynamic buffer to substitute the traditional fixed buffer.According to the existing measurements and our simulation results, using the traditional static buffer in a dynamic peer-to-peer environment has a limit of improving quality of service. In our proposed method, the buffering mechanism can adjust buffer to avoid the frozen or reboot of streaming based on the input data rate. A self-adjusted buffer control can be suitable for the violently dynamic peer-to-peer environment. Without any support of infrastructure and modification of peer-to-peer protocols, our proposed scheme can be workable in any chunk-based peer-to-peer streaming delivery. Hence, our proposed dynamic buffering mechanism varies the existing peer-to-peer live streaming system less to improve quality of experience more.

  6. Influence of phosphate ions on buffer capacity of soil humic acids

    Science.gov (United States)

    Boguta, P.; Sokołowska, Z.

    2012-02-01

    The object of this study was to determine change of natural buffer capacity of humic acids by strong buffering agents, which were phosphate ions. Studies were carried out on the humic acids extracted from peat soils. Additional information was obtained by determination of water holding capacity, density, ash and pH for peats and optical parameter Q4/6 for humic acids. Humic acid suspensions exhibited the highest buffer properties at low pH and reached maximum at pH ~ 4. Phosphates possessed buffer properties in the pH range from 4.5 to 8.0. The maximum of buffering was at pH~6.8 and increased proportionally with an increase in the concentration of phosphate ions. The study indicated that the presence of phosphate ions may strongly change natural buffer capacity of humic acids by shifting buffering maximum toward higher pH values. Significant correlations were found for the degree of the secondary transformation with both the buffer capacity and the titrant volume used during titration.

  7. Retrieval analysis of a failed TriboFit polycarbonate urethane acetabular buffer.

    Science.gov (United States)

    Biant, Leela C; Gascoyne, Trevor C; Bohm, Eric R; Moran, Matthew

    2016-03-01

    The purpose of this research was to determine the failure mechanisms and damage features of a TriboFit acetabular buffer implanted directly against a native, prepared acetabulum which was revised after 11months. Retrieval analyses were carried out via light microscopy, gravimetric wear assessment, and observer scoring of visible damage features on the buffer. The volume of material abraded from the backside of the buffer was estimated via three-dimensional reconstruction using a laser scanner. Scanning electron microscopy was used to confirm damage features and mechanisms. Severe abrasion to the backside of the buffer was the primary damage feature, while stippling damage was seen on the articular surface of the buffer. Material loss due to backside abrasion was approximated to be between 0.13360.085 g (gravimetric analyses) and 0.19360.053 g (three-dimensional reconstruction). Implantation of the TriboFit buffer against the patient's native acetabulum without a metal backing allowed for significant movement of the buffer against the bone, resulting in the abrasion seen on this implant. The stippling damage on the articular surface indicates an adhesive wear mechanism which exacerbates movement of the buffer against the acetabulum, thereby increasing backside abrasion. PMID:26833696

  8. The importance of moisture buffering for indoor climate and energy conditions of buildings

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2007-01-01

    A new Nordic test method specifies a test protocol for determination of the so-called Moisture Buffer Value (MBV) of building materials. But how important is moisture buffering to determine the indoor humidity condition of buildings? The paper will present the new MBV-definition. Although it is...

  9. Influence of Herbaceous Riparian Buffers on Channelized Headwater Streams in Central Ohio

    Science.gov (United States)

    Herbaceous riparian buffers are a widely used conservation practice in the United States for reducing nutrient, pesticide, and sediment loadings in agricultural streams. The importance of forested riparian buffers for headwater streams has been documented, but the ecological impacts of herbaceous ri...

  10. Forest transpiration from sap flux density measurements in a Southeastern Coastal Plain riparian buffer system

    Science.gov (United States)

    Forested riparian buffers are prevalent throughout the Southeastern Coastal Plain Region of the United States (US). Because they make up a significant portion of the regional landscape, transpiration within these riparian buffers is believed to have an important impact on the hydrologic budget of r...

  11. 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…

  12. An advice concerning the quantity of buffer solution used in lanthanide complexometric analysis

    International Nuclear Information System (INIS)

    The influence of buffer quantity used in the titration of complexometric analysis of lanthanides is presented. This allows to determine the optimum quantity of buffer which shows reproducible results. La (NO3)3.4 dmSO samples are used in the analysis. (A.R.H.)

  13. Analysis of Power-aware Buffering Schemes in Wireless Sensor Networks

    CERN Document Server

    Ling, Yibei; Chen, Shigang; 10.1145/1807048.1807055

    2011-01-01

    We study the power-aware buffering problem in battery-powered sensor networks, focusing on the fixed-size and fixed-interval buffering schemes. The main motivation is to address the yet poorly understood size variation-induced effect on power-aware buffering schemes. Our theoretical analysis elucidates the fundamental differences between the fixed-size and fixed-interval buffering schemes in the presence of data size variation. It shows that data size variation has detrimental effects on the power expenditure of the fixed-size buffering in general, and reveals that the size variation induced effects can be either mitigated by a positive skewness or promoted by a negative skewness in size distribution. By contrast, the fixed-interval buffering scheme has an obvious advantage of being eminently immune to the data-size variation. Hence the fixed-interval buffering scheme is a risk-averse strategy for its robustness in a variety of operational environments. In addition, based on the fixed-interval buffering schem...

  14. Biocompatibility and tolerability of a purely bicarbonate-buffered peritoneal dialysis solution.

    NARCIS (Netherlands)

    Weiss, L.; Stegmayr, B.; Malmsten, G.; Tejde, M.; Hadimeri, H.; Siegert, C.E.; Ahlmen, J.; Larsson, R.; Ingman, B.; Simonsen, O.; Hamersvelt, H.W. van; Johansson, A.C.; Hylander, B.; Mayr, M.; Nilsson, P.H.; Andersson, P.O.; Los Rios, T. De

    2009-01-01

    BACKGROUND: Novel peritoneal dialysis solutions are characterized by a minimal content of glucose degradation products and a neutral pH. Many studies have shown the biocompatibility of neutral lactate-buffered solutions; however, until now, the effect of purely bicarbonate-buffered solutions has not

  15. Influence of different buffers (HEPES/MOPS) on keratinocyte cell viability and microbial growth.

    Science.gov (United States)

    Dias, Kássia de Carvalho; Barbugli, Paula Aboud; Vergani, Carlos Eduardo

    2016-06-01

    This study assessed the effect of the buffers 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) and 3-(N-morpholino) propanesulfonic acid (MOPS) on keratinocyte cell viability and microbial growth. It was observed that RPMI buffered with HEPES, supplemented with l-glutamine and sodium bicarbonate, can be used as a more suitable medium to promote co-culture. PMID:27060444

  16. 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).

  17. 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 gree

  18. 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.

  19. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D

    2015-03-31

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  20. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.

    2013-03-12

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

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

    International Nuclear Information System (INIS)

    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)

  2. 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.

  3. Propagation of misfit dislocations from buffer/Si interface into Si

    Science.gov (United States)

    Liliental-Weber, Zuzanna; Maltez, Rogerio Luis; Morkoc, Hadis; Xie, Jinqiao

    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.

  4. Evaluation of Sikora instead of SMP buffer to estimate the potential acidity of brazilian soils

    Directory of Open Access Journals (Sweden)

    Maria Alice Santanna

    2011-10-01

    Full Text Available Despite the efficiency of the Shoemaker, McLean, Pratt (SMP buffer method in estimating soil acidity, the presence of p-nitrophenol and potassium chromate in the solution, both hazardous substances, has caused increasing environmental concerns. The purpose of this study was to test Sikora method (Sikora, 2006 as an alternative to the adapted SMP buffer method, generally used to estimate potential acidity of Southern Brazilian soils. For the test, 21 soils in the South and Cerrado regions of Brazil were sampled. (1 The potential acidity values of these soils range from 35.95 to 4.02 cmol c kg-1 of soil, reflecting a wide acidity variation. The Sikora buffer does not mimic the adapted SMP buffer used in Southern Brazil, since the former has a low ability to distinguish soils with different acidity from each other, probably due to the higher buffer capacity than of the adapted SMP solution.

  5. Copper variation in Cu(In,Ga)Se2 solar cells with indium sulphide buffer layer

    International Nuclear Information System (INIS)

    In the manufacturing of Cu(In,Ga)Se2 (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 InxSy-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 InxSy 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

  6. New MBE buffer for micron- and quarter-micron-gateGaAs MESFETs

    Science.gov (United States)

    1988-01-01

    A new buffer layer has been developed that eliminates backgating in GaAs MESFETs and substantially reduces short-channel effects in GaAs MESFETs with 0.27-micron-long gates. The new buffer is grown by molecular beam epitaxy (MBE) at a substrate temperature of 200 C using Ga and As sub 4 beam fluxes. The buffer is crystalline, highly resistive, optically inactive, and can be overgrown with high quality GaAs. GaAs MESFETs with a gate length of 0.27 microns that incorporate the new buffer show improved dc and RF properties in comparison with a similar MESFET with a thin undoped GaAs buffer. To demonstrate the backgating performance improvement afforded by the new buffer, MESFETs were fabricated using a number of different buffer layers and structures. A schematic cross section of the MESFET structure used in this study is shown. The measured gate length, gate width, and source-drain spacing of this device are 2,98, and 5.5 microns, respectively. An ohmic contact, isolated from the MESFET by mesa etching, served as the sidegate. The MESFETs were fabricated in MBE n-GaAs layers grown on the new buffer and also in MBE n-GaAs layers grown on buffer layers of undoped GaAs, AlGaAs, and GaAs/AlGaAs superlattices. All the buffer layers were grown by MBE and are 2 microns thick. The active layer is doped to approximately 2 x 10 to the 17th/cu cm with silicon and is 0.3 microns thick.

  7. Buffering PV output during cloud transients with energy storage

    Science.gov (United States)

    Moumouni, Yacouba

    Consideration of the use of the major types of energy storage is attempted in this thesis in order to mitigate the effects of power output transients associated with grid-tied CPV systems due to fast-moving cloud coverage. The approach presented here is to buffer intermittency of CPV output power with an energy storage device (used batteries) purchased cheaply from EV owners or battery leasers. When the CPV is connected to the grid with the proper energy storage, the main goal is to smooth out the intermittent solar power and fluctuant load of the grid with a convenient control strategy. This thesis provides a detailed analysis with appropriate Matlab codes to put onto the grid during the day time a constant amount of power on one hand and on the other, shift the less valuable off-peak electricity to the on-peak time, i.e. between 1pm to 7pm, where the electricity price is much better. In this study, a range of base constant power levels were assumed including 15kW, 20kW, 21kW, 22kW, 23kW, 24kW and 25kW. The hypothesis based on an iterative solution was that the capacity of the battery was increased by steps of 5 while the base supply was decreased by the same step size until satisfactorily results were achieved. Hence, it turned out with the chosen battery capacity of 54kWh coupled to the data from the Amonix CPV 7700 unit for Las Vegas for a 3-month period, it was found that 20kW was the largest constant load the system can supply uninterruptedly to the utility company. Simulated results are presented to show the feasibility of the proposed scheme.

  8. Gray Wolves as Climate Change Buffers in Yellowstone

    Directory of Open Access Journals (Sweden)

    Wilmers Christopher C

    2005-01-01

    Full Text Available Understanding the mechanisms by which climate and predation patterns by top predators co-vary to affect community structure accrues added importance as humans exert growing influence over both climate and regional predator assemblages. In Yellowstone National Park, winter conditions and reintroduced gray wolves (Canis lupus together determine the availability of winter carrion on which numerous scavenger species depend for survival and reproduction. As climate changes in Yellowstone, therefore, scavenger species may experience a dramatic reshuffling of food resources. As such, we analyzed 55 y of weather data from Yellowstone in order to determine trends in winter conditions. We found that winters are getting shorter, as measured by the number of days with snow on the ground, due to decreased snowfall and increased number of days with temperatures above freezing. To investigate synergistic effects of human and climatic alterations of species interactions, we used an empirically derived model to show that in the absence of wolves, early snow thaw leads to a substantial reduction in late-winter carrion, causing potential food bottlenecks for scavengers. In addition, by narrowing the window of time over which carrion is available and thereby creating a resource pulse, climate change likely favors scavengers that can quickly track food sources over great distances. Wolves, however, largely mitigate late-winter reduction in carrion due to earlier snow thaws. By buffering the effects of climate change on carrion availability, wolves allow scavengers to adapt to a changing environment over a longer time scale more commensurate with natural processes. This study illustrates the importance of restoring and maintaining intact food chains in the face of large-scale environmental perturbations such as climate change.

  9. Gray wolves as climate change buffers in Yellowstone.

    Directory of Open Access Journals (Sweden)

    Christopher C Wilmers

    2005-04-01

    Full Text Available Understanding the mechanisms by which climate and predation patterns by top predators co-vary to affect community structure accrues added importance as humans exert growing influence over both climate and regional predator assemblages. In Yellowstone National Park, winter conditions and reintroduced gray wolves (Canis lupus together determine the availability of winter carrion on which numerous scavenger species depend for survival and reproduction. As climate changes in Yellowstone, therefore, scavenger species may experience a dramatic reshuffling of food resources. As such, we analyzed 55 y of weather data from Yellowstone in order to determine trends in winter conditions. We found that winters are getting shorter, as measured by the number of days with snow on the ground, due to decreased snowfall and increased number of days with temperatures above freezing. To investigate synergistic effects of human and climatic alterations of species interactions, we used an empirically derived model to show that in the absence of wolves, early snow thaw leads to a substantial reduction in late-winter carrion, causing potential food bottlenecks for scavengers. In addition, by narrowing the window of time over which carrion is available and thereby creating a resource pulse, climate change likely favors scavengers that can quickly track food sources over great distances. Wolves, however, largely mitigate late-winter reduction in carrion due to earlier snow thaws. By buffering the effects of climate change on carrion availability, wolves allow scavengers to adapt to a changing environment over a longer time scale more commensurate with natural processes. This study illustrates the importance of restoring and maintaining intact food chains in the face of large-scale environmental perturbations such as climate change.

  10. Use of clays as buffers in radioactive repositories

    International Nuclear Information System (INIS)

    For use as canister overpack, highly compacted bentonite is superior to illite and any reasonably montmorillonite-rich bentonite will do which is not too rich in sulphur. The organic content should be low and heat treatment may be required to bring this content down to an acceptable level. Heating to slightly more than 400degreeC does not affect the physical properties of neither montmorillonite, nor illite to a significant extent. Bentonite is also very suitable for use as sealing plugs in the form of highly compacted blocks. For use as backfill in tunnels and shafts, illitic clay is a candidate material which can be compacted on site to the rather high density that is required. Where a swelling capacity is needed, such as in the top part of tunnels, bentonite-based backfills are suitable and if Na saturated clay is used the bentoite fraction can be kept low. Thus, a 10 percent content of Na bentonite by weight should generally be sufficient for a well compacted mixture with respect to the required hydraulic conductivity, while a 20-30 percent content may be needed to arrive at a sufficient swelling power. The choice of a suitable clay material requires that the substance be properly characterized and tested. It is concluded that rather rigorous analyses are necessary as concerns overpacks, including mineralogical and granulometrical tests and the determination of the swelling characteristics as well as of certain chemical features. For backfills and for the current checking of all sorts of clay for use as buffer materials, the natural water content, the liquid limit and the swelling ability have to be determined, since they are the fingerprints of this type of soil. (author)

  11. Can alternative sugar sources buffer pollinators from nectar shortages?

    Science.gov (United States)

    Gardner-Gee, Robin; Dhami, Manpreet K; Paulin, Katherine J; Beggs, Jacqueline R

    2014-12-01

    Honeydew is abundant in many ecosystems and may provide an alternative food source (a buffer) for pollinators during periods of food shortage, but the impact of honeydew on pollination systems has received little attention to date. In New Zealand, kānuka trees (Myrtaceae: Kunzea ericoides (A. Rich) Joy Thompson) are often heavily infested by the endemic honeydew-producing scale insect Coelostomidia wairoensis (Maskell) (Hemiptera: Coelostomidiidae) and the period of high honeydew production can overlap with kānuka flowering. In this study, we quantified the sugar resources (honeydew and nectar) available on kānuka and recorded nocturnal insect activity on infested and uninfested kānuka during the flowering period. Insects were abundant on infested trees, but flowers on infested trees received fewer insect visitors than flowers on uninfested trees. There was little evidence that insects had switched directly from nectar-feeding to honeydew-feeding, but it is possible that some omnivores (e.g., cockroaches) were distracted by the other honeydew-associated resources on infested branches (e.g., sooty molds, prey). Additional sampling was carried out after kānuka flowering had finished to determine honeydew usage in the absence of adjacent nectar resources. Moths, which had fed almost exclusively on nectar earlier, were recorded feeding extensively on honeydew after flowering had ceased; hence, honeydew may provide an additional food source for potential pollinators. Our results show that honeydew resources can impact floral visitation patterns and suggest that future pollinator studies should consider the full range of sugar resources present in the study environment. PMID:25368982

  12. Evaluation of the outflow characteristic of bentonite buffer material. 2

    International Nuclear Information System (INIS)

    The outflow behaviour of bentonite buffer material was experiment to assess the physical stability in the geological disposal system, the parameters of experiment are the dry density of bentonite, mixtures ratio silica sand, fracture width, and flow velocity. The outflow phenomena were identified as extrusion and erosion, and the experimental results are as follows; 1) Extrusion: The proportional coefficient obtained from the relation between time and extrusion distance was arranged by the relation with effective clay density. The experimental equation of the proportional coefficient is as follows; A = 6.7587x10-7∼ exp(5.7261d)∼ exp((6.1598+(-0.5398d)+(-0.9272d2))∼ Pb). By model experiment, the density distribution into fracture was measured. The density distribution of an extrusion region obtained 0.8-0.2 Mgm-3. The average dry density into fracture of bentonite gel was about 0.4 Mgm-3 below. The influence of density of bentonite/sand mixtures material (30 wt%, 1.6 Mgm-3) by the extrusion phenomenon was calculated. It was assumed that the average fracture density is about eight fractures parameter. The reduction in density of the bentonite/sand mixtures material is about 4.5% (1.527 Mgm-3) of the initial value after 10,000 years. 2) Erosion: The colloid concentration and the particle size in drainage liquid were measured as parameter of flow velocity into fracture. The result of measurement, colloid concentration decreased with the increase in the flow velocity. Moreover, the particle size of colloid became large. In the case of average flow velocity 1E-5 ms-1, the colloid was generated in drainage liquid. Therefore, the flow velocity for occurrence of erosion was suggested smaller than 1E-5 ms-1. (author)

  13. Buffer mass test - Rock drilling and civil engineering

    International Nuclear Information System (INIS)

    The buffer mass test (BMT) is being run in the former 'ventilation drift' in which a number of rock investigations were previously conducted. A number of vertical pilot holes were drilled from the tunnel floor to get information of the water inflow in possible heater hole position. The final decision of the location of the heater holes was then made, the main principle being that much water should be available in each hole with the possible exception of one of the holes. Thereafter, the diameter 0.76 m heater holes were drilled to a depth of 3-3.3 m. Additional holes were then drilled for rock anchoring of the lids of the four outer heater holes, for the rock mechanical investigation, as well as for a number of water pressure gauges. The inner, about 12 m long part of the tunnel, was separated from the outer by bulwark. The purpose of this construction was to confine a backfill, the requirements of the bulwark being to withstand the swelling pressure as well as the water pressure. Outside the bulwark an approximately 1.5-1.7 m thick concrete slab was cast on the tunnel floor, extending about 24.7 m from the bulwark. Boxing-outs with the same height as the slab and with the horizontal dimensions 1.8 x 1.8 m, were made and rock-anchored concrete lids were cast on top of them after backfilling. The slab which thus represents 'rock', also forms a basal support of the bulwark. The lids permits access to the backfill as well as to the underlying, highly compacted bentonite for rapid direct determination of the water distributin at the intended successive test stops. The construction of the slab and lids will be described in this report. (Author)

  14. Erosion of bentonite buffer in a KBS-3 repository

    International Nuclear Information System (INIS)

    accounted for in the simulations. The sodium concentration profile in the gel influences the repulsive forces between the particles as well as the viscosity of the expanding gel. Under the most unfavourable circumstances, i.e. at high flowrates and large fracture apertures, considerable loss of smectite can be expected for a buffer that consists of only smectite Other calculations have been made to assess under which conditions of flowrate, water compositions and initial bentonite chemical compositions the water composition at the gel/water interface could become larger than the CCC. At the same time the proportion of calcium and sodium as counter ions in the smectite at the gel/water interface was studied. This was done because should the calcium make up more than about 90 % of the counterions, the smectite behaves very differently from than smectite with less calcium. There are indications that such gel will not release colloids readily. In a number of studied cases such stabilizing conditions could not be achieved. In these calculations we have accounted for ion exchange in the expanding gel, for diffusion of ions in the gel, for transport to and from the seeping groundwater, and of the dissolution of soluble minerals that may supply the gel with ions. We conclude that with our present understanding of the processes it is not possible to affirmatively state that erosion of pure smectite gels cannot occur to a considerable extent. However, the commercial bentonites that have been extensively investigated in earlier and present SKB investigations contain tens of percent of non-smectic accessory minerals. These materials do not exhibit the strong repulsive forces as the smectites do because the surface charge density is essentially negligible at the circum neutral pH expected. Furthermore the particle size of these materials is one to two orders of magnitude larger than those of the smectite particles, so they are much less mobile and they could not be lost as colloids in

  15. 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

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

    International Nuclear Information System (INIS)

    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 (HCO3−) 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 HCO3− was an important buffering mechanism in both streams. Base cation, Fe2+, 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-solute poorly

  17. 2D and 3D finite element analysis of buffer-backfill interaction

    International Nuclear Information System (INIS)

    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/m3. 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 3D

  18. PERFORMANCE IMPROVEMENT USING FUZZY BASED DYNAMIC BUFFER SCHEME FOR EFFICIENT RRM IN WIMAX 16M NETWORKS

    Directory of Open Access Journals (Sweden)

    D.Karunkuzhali

    2012-12-01

    Full Text Available The IEEE 802.16m standard for Advanced mobile broadband wireless access provides a seamless application connectivity to other mobile and IP networks like UMTS, LTE and WLAN. In order to meet theubiquitous service delivery for users, Wimax 16m supports integration of these diverse networks which are having great difference in terms of data transmission rate, Coverage, cost and supporting of service types. Here, buffer allocation is the major problem to be handled for offering Quality of Service (QoS. The lack of buffers increases the packet loss and queuing delay. In order to overcome these issues, in this paper we propose a fuzzy based dynamic buffer scheme to improve RRM in WiMAX 16m network. The base station (BS estimates theparameters such as number of user requests, flow rate, queue length and received signal strength for each user and updates them periodically. When a request arrives at BS, buffer allocation factor is estimated by applying fuzzy logic over these parameters. Then the flow request with high buffer allocation factor is admitted first andrest of the flow requests waits in a queue. Upon new request arrival, if its buffer allocation factor is low, the request is rejected. Otherwise, the pending request packet in the queue is emptied on analyzing their channel condition and buffer is allocated for new request. By simulation results, we show that the proposed techniqueFBDBM achieves better utilization when compared with MWRR scheme, while increasing the traffic flows.

  19. Subjective well-being, social buffering and hedonic editing in the quotidian.

    Science.gov (United States)

    Sul, Sunhae; Kim, Jennifer; Choi, Incheol

    2016-09-01

    A previous study on the relationship between subjective well-being (SWB) and hedonic editing-the process of mentally integrating or segregating different events during decision-making-showed that happy individuals preferred the social-buffering strategy more than less happy individuals. The present study examined the relationship between SWB, social-buffering and hedonic outcomes in daily life. In Study 1, we used web-based diaries to measure the frequency with which individuals utilised social and non-social buffers as well as daily levels of happiness. Consistent with the previous finding, happy individuals utilised social buffers more frequently than less happy individuals. Interestingly, the utilisation of social buffers had a positive effect on daily happiness among all participants, regardless of individuals' levels of SWB. In Study 2, we found that although the use of social buffers yielded similar effects across groups on online evaluations of events, happy individuals showed a positive bias in global evaluations of past events. This finding suggests that how one construes and remembers the outcomes of social buffering may shape the different hedonic editing preferences among happy and less happy individuals. PMID:26192269

  20. The impact of buffer strips and stream-side grazing on small mammals in southwestern Wisconsin

    Science.gov (United States)

    Chapman, Erik W.; Ribic, C.A.

    2002-01-01

    The practice of continuously grazing cattle along streams has caused extensive degradation of riparian habitats. Buffer strips and managed intensive rotational grazing (MIRG) have been proposed to protect and restore stream ecosystems in Wisconsin. However, the ecological implications of a switch from traditional livestock management to MIRG or buffer strip establishment have not been investigated. Differences in small mammal communities associated with riparian areas on continuously grazed and MIRG pastures, as well as vegetative buffer strips adjacent to row crops, were investigated in southwestern Wisconsin during May-September 1997 and 1998. More species (mean of 6-7) were found on the buffer sites than on the pasture sites (mean of 2-5). Total small mammal abundance on buffer sites was greater than on the pastures as well: there were 3-5 times as many animals on the buffer sites compared to the pasture sites, depending on year. There were no differences in species richness or total abundance between MIRG and continuously grazed pastures in either year. Total small mammal abundance was greater near the stream than away from the stream, regardless of farm management practice but there were no differences in species richness. Buffer strips appear to support a particularly rich and abundant small mammal community. Although results did not detect a difference in small mammal use between pasture types, farm-wide implications of a conversion from continuous to MIRG styles of grazing may benefit small mammals indirectly by causing an increase in the prevalence of pasture in the agricultural landscape.

  1. Scheduling Packets with Values and Deadlines in Size-bounded Buffers

    CERN Document Server

    Li, Fei

    2010-01-01

    Motivated by providing quality-of-service differentiated services in the Internet, we consider buffer management algorithms for network switches. We study a multi-buffer model. A network switch consists of multiple size-bounded buffers such that at any time, the number of packets residing in each individual buffer cannot exceed its capacity. Packets arrive at the network switch over time; they have values, deadlines, and designated buffers. In each time step, at most one pending packet is allowed to be sent and this packet can be from any buffer. The objective is to maximize the total value of the packets sent by their respective deadlines. A 9.82-competitive online algorithm has been provided for this model (Azar and Levy. SWAT 2006), but no offline algorithms have been known yet. In this paper, We study the offline setting of the multi-buffer model. Our contributions include a few optimal offline algorithms for some variants of the model. Each variant has its unique and interesting algorithmic feature. Thes...

  2. 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

    Oxygen fugacity (fO2) controls multivalent phase equilibria and partitioning of redox-sensitive elements, and it is important to understand this thermodynamic parameter in experimental and natural systems. The coexistence of a metal and its oxide at equilibrium constitutes an oxygen buffer which can be used to control or calculate fO2 in high pressure experiments. Application of 1-bar buffers to high pressure conditions can lead to inaccuracies in fO2 calculations because of unconstrained pressure dependencies. Extending fO2 buffers to pressures and temperatures corresponding to the Earth's deep interior requires precise determinations of the difference in volume (Delta) V) between the buffer phases. Synchrotron x-ray diffraction data were obtained using diamond anvil cells (DAC) and a multi anvil press (MAP) to measure unit cell volumes of W and WO2 at pressures and temperatures up to 70 GPa and 2300 K. These data were fitted to Birch-Murnaghan 3rd-order thermal equations of state using a thermal pressure approach; parameters for W are KT = 306 GPa, KT' = 4.06, and aKT = 0.00417 GPa K-1. Two structural phase transitions were observed for WO2 at 4 and 32 GPa with structures in P21/c, Pnma and C2/c space groups. Equations of state were fitted for these phases over their respective pressure ranges yielding the parameters KT = 190, 213, 300 GPa, KT' = 4.24, 5.17, 4 (fixed), and aKT = 0.00506, 0.00419, 0.00467 GPa K-1 for the P21/c, Pnma and C2/c phases, respectively. The W-WO2 buffer (WWO) was extended to high pressure by inverting the W and WO2 equations of state to obtain phase volumes at discrete pressures (1-bar to 100 GPa, 1 GPa increments) along isotherms (300 to 3000K, 100 K increments). The slope of the absolute fO2 of the WWO buffer is positive with increasing temperature up to approximately 70 GPa and is negative above this pressure. The slope is positive along isotherms from 1000 to 3000K with increasing pressure up to at least 100 GPa. The WWO buffer is at

  3. Preparation and quality control of materials used in the reference buffer material

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, D.A.; Hnatiw, D.S.J.; Kohle, C.L.

    1992-09-15

    This document summarizes the methodologies developed for preparing the reference buffer material (RBM) for use in laboratory-scale and field-scale experiments. Two commercially available concrete mixers have been successfully used to repeatedly produce homogeneous bulk buffer and backfill materials. The components, blending procedures, quality control sampling requirements, and mixing checklists used in the production of the reference buffer material are presented. Use of these directions will ensure that consistent batching of sealing materials is achieved and operator-induced variability is minimized.

  4. SYSTEM AGGREGATION METHOD FOR FAILURE PRONE PRODUCTION LINES WITH UNRELIABLE LIMITED BUFFERS

    Institute of Scientific and Technical Information of China (English)

    LIU Jun; RUI Zhiyuan; ZHAO Juntian; WEI Yaobing

    2008-01-01

    Different from traditional aggregation method, the unreliable buffers are originally considered and a more general aggregation method is offered, in which not only the unreliable buffers are considered, but also the probabilities of system states are obtained by a discrete model rather than the continuous flow model of unreliable manufacturing systems. The solution technique is offered to get the system sate probabilities. The method advances the traditional system aggregation techniques. Numerical results specify the extended aggregation method and also show that the unreliable limited buffers have a strong impact on the efficiency of the production lines.

  5. Comparator circuits with local ramp buffering for a column-parallel single slope ADC

    Energy Technology Data Exchange (ETDEWEB)

    Milkov, Mihail M.

    2016-04-26

    A comparator circuit suitable for use in a column-parallel single-slope analog-to-digital converter comprises a comparator, an input voltage sampling switch, a sampling capacitor arranged to store a voltage which varies with an input voltage when the sampling switch is closed, and a local ramp buffer arranged to buffer a global voltage ramp applied at an input. The comparator circuit is arranged such that its output toggles when the buffered global voltage ramp exceeds the stored voltage. Both DC- and AC-coupled comparator embodiments are disclosed.

  6. Characteristics study of bentonite as candidate of buffer materials for radioactive waste disposal system

    International Nuclear Information System (INIS)

    Literature studies on bentonite characteristic of, as candidate for radioactive waste disposal system, have been conducted. Several information have been obtained from references, which would be contributed on performance assessment of engineered barrier. The functions bentonite includes the buffering of chemical and physical behavior, i.e. swelling property, self sealing, hydraulic conductivities and gas permeability. This paper also presented long-term stability of bentonite in natural condition related to the illitisazation, which could change its buffering capacities. These information, showed that bentonite was satisfied to be used for candidate of buffer materials in radioactive waste disposal system. (author)

  7. Study on the influence of a specification of buffer material on the compaction characteristics

    International Nuclear Information System (INIS)

    In order to build up the construction technology of buffer for geological disposal of radioactive waste, it is necessary to investigate the compaction characteristics of mixture material of bentonite and silica sand. From the results of static compaction experiment, relation between specifications of buffer and compaction characteristic was investigated. And the particle action mechanism during compaction was investigated by comparison between dynamic compaction and static compaction, and by microscopic observation. As results, the influence factors on compaction characteristics of buffer material are shown from the viewpoint of particle action mechanism. (author)

  8. MgO buffer layers on rolled nickel or copper as superconductor substrates

    Science.gov (United States)

    Paranthaman, Mariappan; Goyal, Amit; Kroeger, Donald M.; List, III, Frederic A.

    2001-01-01

    Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

  9. Method for making MgO buffer layers on rolled nickel or copper as superconductor substrates

    Science.gov (United States)

    Paranthaman, Mariappan; Goyal, Amit; Kroeger, Donald M.; List, III, Frederic A.

    2002-01-01

    Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

  10. Effects of buffer concentration on voltage-gated H+ currents: does diffusion limit the conductance?

    OpenAIRE

    DeCoursey, T.E.; Cherny, V. V.

    1996-01-01

    The single-channel proton conductance of the voltage-gated H(+)-selective channel, like that of the F0 component of the H(+)-ATPase, is nearly constant over a wide range of pH encompassing the physiological range. To examine the possible contributions of buffer diffusion and buffer-channel proton transfer reactions to this phenomenon, the effects of buffer concentration on voltage-activated H+ currents were explored in voltage-clamped rat alveolar epithelial cells. Changes in the external buf...

  11. Design on Buffer Structure of Traction Running with a Constant Speed

    Directory of Open Access Journals (Sweden)

    Zeng Xianren

    2013-06-01

    Full Text Available This study mainly aims to study buffer structure design on the traction transport system when the traction transport boundary conditions are given. With such conditions as the maximum impact force, traction speed, maximum speed of alluvium, the elasticity coefficient and the mass of buffer structure, a mathematical model was established and the solution of differential equations was solved. At last, a program was compiled with MATLAB language. With this program the elasticity coefficient and the maximum impact force which meet the requirements in impact process can be solved as long as the boundary conditions are input. This provides a quick design basis of buffer structure for most mechanical engineers.

  12. Light Confinement by a Cylindric Metallic Waveguide in Dense Buffer Gas Environment

    CERN Document Server

    Vogl, Ulrich; Vewinger, Frank; Weitz, Martin; Solovev, Alexander; Mei, Yongfeng; Schmidt, Oliver

    2010-01-01

    We report on the implementation of metallic microtubes in a system of rubidium vapour at 230\\,bar of argon buffer gas. The high buffer gas pressure leads to a widely pressure broadened linewidth of several nanometers, interpolating between the sharp atomic physics spectra and the band structure of solid state systems. Tube-like metallic waveguide structures have been inserted in the high pressure buffer gas system, allowing for an enhancement of the atom-light interaction over an optical guiding length in the tube of up to 1\\,mm. The system holds promise for nonlinear optics experiments and the study of atom-light polariton condensation.

  13. Band gap engineering of the ZnO/Si heterojunction using amorphous buffer layers

    OpenAIRE

    Ingebrigtsen, Mads Eide

    2014-01-01

    Zinc oxide is attractive for photovoltaic applications due to its properties as Transparent Conductive Oxide (TCO), as well as for rectifying heterojunctions to silicon. The present work investigates the electrical properties of the ZnO/Si heterojunction and the influence of buffer layers; i.e. ZnO/buffer/Si structures. The structures have been produced with buffer thicknesses in the range 5-20 nm, composed of amorphous silicon (aSi), silicon germanium (aSiGe) or silicon carbide (aSiC). The c...

  14. Dynamic Floating Output Stage for Low Power Buffer Amplifier for LCD Application

    Directory of Open Access Journals (Sweden)

    Hari Shanker Srivastava

    2015-02-01

    Full Text Available This topic proposes low-power buffer means low quiescent current buffer amplifier. A dynamic floating current node is used at the output of two-stage amplifier to increase the charging and discharging of output capacitor as well as settling time of buffer. It is designed for 10 bit digital analog converter to support for LCD column driver it is implemented in 180 nm CMOS technology with the quiescent current of 5 µA for 30 pF capacitance, the settling time calculated as 4.5µs, the slew rate obtained as 5V/µs and area on chip is 30×72µ

  15. Optimized DPPH assay in a detergent-based buffer system for measuring antioxidant activity of proteins

    OpenAIRE

    Nicklisch, Sascha C.T.; Herbert Waite, J.

    2014-01-01

    © 2014 The Authors. (Graph Presented) The free radical method using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) is a well established assay for the in vitro determination of antioxidant activity in food and biological extracts. The standard DPPH assay uses methanol or ethanol as solvents, or buffered alcoholic solutions in a ratio of 40%/60% (buffer/alcohol, v/v) to keep the hydrophobic hydrazyl radical and phenolic test compounds soluble while offering sufficient buffering capacity at different pH...

  16. Buffer component manufacturing by uniaxial compression method. Small scale

    International Nuclear Information System (INIS)

    The purpose of this work was to gain better understanding about the method of uniaxial compression for the production of bentonite buffer components. Manufacturing by uniaxial was done in laboratory conditions to produce small cylindrical samples. The goal was to produce samples with sufficient bulk density according to the design needs, as well as to have homogenous density distribution and minimal defects in the sample. The testing was done using MX-80 bentonite as the reference material according to the production line plan. The water content was typically 17 %, though a few additional tests were done in ranges from 13 % to 22 %. Compression was done at 100 MPa for a target bulk density of approximately 2100 kg/m3. The final compressed sample size typically was 100 mm in diameter by 100 mm in height. Four different mould arrangements were used, including moulds with straight or inclined (0.5 deg) walls, moulds with insert tube liners, 3-part opening mould, and dual direction pressing mould. Approximately 10 different types of lubricants were used to reduce friction, including single-use spray, powder or grease lubricants, permanent mould liner coatings and single use foil liners. Post compression assessment included measurement of bulk and dry density over the height of the samples and visual observation of defects and/or cracking. In some cases tensile and compressive strength were tested. Microscopic investigations of the surfaces provided information about lubricant penetration to the bentonite. The results showed that it was possible to obtain uniform, defect free bentonite blocks by uniaxial compression. The best samples were obtained with the inclined mould walls and using a high-quality lubricant so that the bulk density variation was under 0.5 % across the sample height. Copper spray was the best lubricant, as well as the Teflon coating. Yet permanent coatings are a better alternative since they do not get entrapped within the bentonite during mould

  17. Photosynthetic activity buffers ocean acidification in seagrass meadows

    Directory of Open Access Journals (Sweden)

    I. E. Hendriks

    2013-07-01

    Full Text Available Macrophytes growing in shallow coastal zones characterized by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH ranges is in shallow (5–12 m seagrass (Posidonia oceanica meadows from 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (ΩAr and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI. LAI was positively correlated to mean and max pHNBS and max ΩAr. Oxygen production positively influenced the range and maximum pHNBS and the range of ΩAr. In June, vertical mixing (as Turbulent Kinetic Energy influenced ΩAr, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. ΩAr was positively correlated with the calcium carbonate load of the leaves, demonstrating a direct link between structural parameters, ΩAr and carbonate deposition. There was a direct relationship between ΩAr, influenced directly by meadow LAI, and CaCO3 content of the leaves. Therefore, calcifying organisms, e.g. epiphytes with carbonate skeletons, might benefit from the modification of the carbonate system by the meadow. The meadow might be capable of providing refugia for calcifiers by increasing pH and ΩAr through metabolic activity. There is, however, concern for the ability of seagrasses to provide this refugia function in the future. The predicted decline of seagrass meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, both strongly linked to LAI. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded meadows.

  18. Performance study of a genetic algorithm for sequencing in mixted model non-permutation flowshops using constrained buffers

    OpenAIRE

    Färber, Gerrit Hartmut; Coves Moreno, Anna Maria

    2006-01-01

    This paper presents the performance study of a Genetic Algorithm applied to a mixed model non-permutation flowshop production line. Resequencing is permitted where stations have access to intermittent or centralized resequencing buffers. The access to the buffers is restricted by the number of available buffer places and the physical size of the products. Characteristics such as the difference between the intermittent and the centralized case, the number of buffer places and the distributi...

  19. HV/CVD Grown Relaxed SiGe Buffer Layers for SiGe HMOSFETs

    Institute of Scientific and Technical Information of China (English)

    黄文韬; 罗广礼; 史进; 邓宁; 陈培毅; 钱佩信

    2003-01-01

    High-vacuum/chemical-vapor deposition (HV/CVD) system was used to grow relaxed SiGe buffer layers on Si substrates. Several methods were then used to analyze the quality of the SiGe films. X-ray diffraction and Raman spectroscopy showed that the upper layer was almost fully relaxed. Second ion mass spectroscopy showed that the Ge compositions were step-graded. Transmission electron microscopy showed that the misfit dislocations were restrained to the graded SiGe layers. Tests of the electrical properties of tensile-strained Si on relaxed SiGe buffer layers showed that their transconductances were higher than that of Si devices. These results verify the high quality of the relaxed SiGe buffer layer. The calculated critical layer thicknesses of the graded Si1-xGex layer on Si substrate and a Si layer on the relaxed SiGe buffer layer agree well with experimental results.

  20. Buffer for the Final Critical Habitat for the Sonora chub (Gila ditaenia)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — To provide the user with a general idea of areas where a buffer for the final critical habitat for Sonora chub (Gila ditaenia) occur based on the description...

  1. EnviroAtlas - Fresno, CA - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  2. EnviroAtlas - New Bedford, MA - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  3. EnviroAtlas - New York, NY - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is forested. In this community, forest is defined as Trees & Forest. There is a...

  4. EnviroAtlas - Woodbine, Iowa - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  5. EnviroAtlas - Portland, OR - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  6. EnviroAtlas - Green Bay, WI - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  7. EnviroAtlas - Phoenix, AZ - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  8. EnviroAtlas - New York, NY - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees & Forest...

  9. EnviroAtlas - Milwaukee, WI - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  10. EnviroAtlas - Pittsburgh, PA - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  11. EnviroAtlas - Phoenix, AZ - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

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

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  13. EnviroAtlas - Woodbine, IA - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  14. EnviroAtlas - Milwaukee, WI - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  15. EnviroAtlas - Pittsburgh, PA - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  16. EnviroAtlas - Paterson, NJ - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  17. EnviroAtlas - New Bedford, MA - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  18. EnviroAtlas - Paterson, NJ - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  19. EnviroAtlas - Green Bay, WI - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  20. EnviroAtlas - Fresno, CA - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  1. EnviroAtlas - Phoenix, AZ - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  2. EnviroAtlas - New York, NY - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees & Forest...

  3. EnviroAtlas - Green Bay, WI - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  4. EnviroAtlas - Pittsburgh, PA - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  5. EnviroAtlas - Phoenix, AZ - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  6. EnviroAtlas - Portland, ME - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  7. EnviroAtlas - Tampa, FL - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  8. EnviroAtlas - Portland, OR - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  9. EnviroAtlas - Portland, ME - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  10. EnviroAtlas - Woodbine, IA - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  11. EnviroAtlas - Milwaukee, WI - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  12. EnviroAtlas - Woodbine, IA - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  13. EnviroAtlas - Memphis, TN - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is forested. Forest is defined as Trees & Forest and Woody Wetlands. There is a...

  14. EnviroAtlas - Fresno, CA - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  15. EnviroAtlas - Tampa, FL - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  16. EnviroAtlas - Green Bay, WI - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  17. EnviroAtlas - Tampa, FL - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  18. EnviroAtlas - Milwaukee, WI - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  19. EnviroAtlas - Fresno, CA - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. There is a potential for decreased water quality in areas where the...

  20. TRIBES - A CPC (Core Protection Calculator)/CEAC (Control Element Assembly Calculator) TRIp Buffer Expert System

    International Nuclear Information System (INIS)

    This paper discusses the development of a small IBM personal computer based expert system to diagnose reactor trips initiated by the Core Protection Calculator, CPC, and the Control Element Assembly Calculator, CEAC. The expert system interprets information from trip buffers created by the CPC and CEAC to determine the reason for the reactor trip. A trip buffer consists of a number of numeric point IDs and their values at the time of the CPC or CEAC channel trip. An expert system approach was chosen because trip buffer interpretation requires a CPC expert to determine the cause of a trip, the knowledge is amenable to formulation in rules and the justification subsystem of an expert system allows a novice user to follow the program's logic to the trip conclusion. The TRIp Buffer Expert System, TRIBES, inference engine is written in TURBO-PROLOG

  1. Spatial Characterization of Riparian Buffer Effects on Sediment Loads from Watershed Systems

    Science.gov (United States)

    Understanding all watershed systems and their interactions is a complex, but critical, undertaking when developing practices designed to reduce topsoil loss and chemical/nutrient transport from agricultural fields. The presence of riparian buffer vegetation in agricultural lands...

  2. Empirical analysis of Brazilian banks' capital buffers during the period 2001-2011

    Directory of Open Access Journals (Sweden)

    Vinícius Cintra Belém

    2016-04-01

    Full Text Available International literature indicates that the capital buffers held by banks result notably from the trade-off that exists between the cost of holding capital, adjustment costs, and bankruptcy costs, which all have a direct impact on banks' capital structures. The aim of this paper is to study the degree of sensitivity of Brazilian banks' capital buffers to the determining factors established in the literature, by using a sample of 121 banks, covering the period from 2001 to 2011. The empirical analysis that was carried out found that there was a significant cost of adjusting capital buffers for the Brazilian banks. At the same time, bankruptcy cost indicated a positive relationship between risk profile and capital buffers, while the cost of holding capital did not exhibit statistical significance in the analysis.

  3. Critical CuI buffer layer surface density for organic molecular crystal orientation change

    International Nuclear Information System (INIS)

    We have determined the critical surface density of the CuI buffer layer inserted to change the preferred orientation of copper phthalocyanine (CuPc) crystals grown on the buffer layer. X-ray reflectivity measurements were performed to obtain the density profiles of the buffer layers and out-of-plane and 2D grazing-incidence X-ray diffraction measurements were performed to determine the preferred orientations of the molecular crystals. Remarkably, it was found that the preferred orientation of the CuPc film is completely changed from edge-on (1 0 0) to face-on (1 1 −2) by a CuI buffer layer with a very low surface density, so low that a large proportion of the substrate surface is bare

  4. EnviroAtlas - New Bedford, MA - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  5. EnviroAtlas - Memphis, TN - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. Forest is defined as Trees & Forest and Woody Wetlands. There is a...

  6. EnviroAtlas - Pittsburgh, PA - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  7. EnviroAtlas - Percent Stream Buffer Zone As Natural Land Cover for the Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset shows the percentage of land area within a 30 meter buffer zone along the National Hydrography Dataset (NHD) high resolution stream...

  8. STUDY AND ENHANCEMENT ON BUFFER MANAGEMENT FOR SMOOTH HANDOVER IN MIPV6

    Institute of Scientific and Technical Information of China (English)

    Lin Huasheng; Jin Yuehui; Cheng Shiduan; Fan Rui

    2005-01-01

    For improving Transfer Control Protocol (TCP) performance in mobile environment,smooth handover with buffer management has been proposed to realize seamless handovers. However in our simulation, even if smooth handover in Mobile IPv6 (MIPv6) is implemented, TCP can not always achieve better performance due to packets forwarding burst. Based on the study of buffer management for smooth handover, this paper proposes an enhanced buffer management scheme for smooth handover to improve TCP performance. In this scheme, a packet-pair probing technology is adopted to estimate the available bandwidth of the new path from Previous router (Prtr) to Mobile Node (MN), which will be used by Prtr to control the buffered packets forwarding. The simulation results demonstrate that smooth handover with this scheme can achieve better TCP performance than the original scheme.

  9. Nature of Y1Ba2Cu3O7 nucleation centers on ceria buffers

    Science.gov (United States)

    Solovyov, Vyacheslav F.; Develos-Bagarinao, Katherine; Li, Qiang; Qing, Jie; Zhou, Juan

    2010-01-01

    The purpose of this study is to enhance properties of the second-generation wires by increasing the density of Y1Ba2Cu3O7 (YBCO) nucleation centers on the surface of the ceria buffer. To identify the nature of the nucleation centers, we compare nucleation kinetics and performance of YBCO layers deposited by the metal-organic process on a standard RABiTS tape to YBCO on ceria buffers with well-controlled structure and surface morphology. The structure of the YBCO layer at the early stage of nucleation and growth is determined by high-flux synchrotron x-ray diffraction. It is shown that the best buffers exhibit high YBCO nucleation rates and produce YBCO nuclei with the least cation disorder. The high YBCO nucleation rate is associated with a high density of threading dislocation outcrops. A strategy for buffer optimization is identified.

  10. EnviroAtlas - Portland, Maine - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  11. EnviroAtlas - Paterson, NJ - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  12. EnviroAtlas - Portland, OR - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  13. Influence of PEDOT: PSS buffer layer on the performance of organic photocoupler

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-qiang; WU Xiao-ming; JING Na; HOU Qing-chuan; Hu Zi-yang; CHENG Xiao-man; HUA Yu-lin; WEI Jun; YIN Shou-gen

    2009-01-01

    We have fabricated an organic photocoupler with organic light-emitting diodes (OLEDs) with 520 nm emissive wavelength as the input light source and a photodiode (PD) based on poly(3-hexylthiophene) (P3HT):1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)-C61 (PCBM) as the detector. The influences of buffer layer (PEDOT:PSS) on output current (Iout), current transfer ratio (CTR) and time response characteristics of the photocoupler device were studied. Through our experiments, It is found that the output current linearly increases with the input current, the max output current and CTR of the devices with PEDOT:PSS buffer layer are 2 times and 7 times than that of the devices without buffer layer respectively, which show that the existence of buffer layer can enhance the output photocurrent efficiently. Moreover, the existence of PEDOT:PSS eliminates the time delay of the devices.

  14. EnviroAtlas - Durham, NC - 51m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  15. EnviroAtlas - Tampa, FL - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  16. EnviroAtlas - Durham, NC - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  17. EnviroAtlas - New York, NY - 15m Riparian Buffer Forest Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is forested. In this community, forest is defined as Trees & Forest. There is a...

  18. EnviroAtlas - Portland, ME - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  19. 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.

  20. A remark on positive topological entropy of N-buffer switched flow networks

    OpenAIRE

    Xiao-Song Yang

    2005-01-01

    We present a simpler elementary proof on positive topological entropy of the N-buffer switched flow networks based on a new simple theorem on positive topological entropy of continuous map on compact metric space.

  1. EnviroAtlas - Sum of population near road without tree buffer for the conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset is a summary of total population near major roads without any tree buffer within 12-digit Hydrologic Units (HUC). The metric is a measure...

  2. Effects of Homo-buffer Layer on Properties of Sputter-deposited ZnO Films

    Institute of Scientific and Technical Information of China (English)

    Jian Huang; Linjun Wang; Run Xu; Weimin Shi; Yiben Xia

    2009-01-01

    Two-step growth regimes were applied to realize a homoepitaxial growth of ZnO films on freestanding diamond substrates by radio-frequency (RF) reactive magnetron sputtering method. ZnO buffer layers were deposited on freestanding diamond substrates at a low sputtering power of 50 W, and then ZnO main layers were prepared on this buffer layer at a high sputtering power of 150 W. For comparison, a sample was also deposited directly on freestanding diamond substrate at a power of 150 W. The effects of ZnO buffer layers on the structural, optical, electrical and morphological properties of the ZnO main layer were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, semiconductor characterization system and atomic force microscopy (AFM) respectively. The experimental results suggested that homo-buffer layer was helpful to improve the crystalline quality of ZnO/diamond heteroepitaxial films.

  3. An Improved MAC Scheme of HORNET Based on Node Structure with Variable Optical Buffer

    Institute of Scientific and Technical Information of China (English)

    Nian Fang; Lutang Wang; Zhaoming Huang

    2003-01-01

    An improved unslotted CSMA/CA MAC scheme of HORNET based on the node structure with variable optical buffer is reported. It can be used for transmitting high effectively all variable IP packets in the WDM network.

  4. Describing the access network by means of router buffer modelling: a new methodology.

    Science.gov (United States)

    Sequeira, Luis; Fernández-Navajas, Julián; Saldana, Jose; Gállego, José Ramón; Canales, María

    2014-01-01

    The behaviour of the routers' buffer may affect the quality of service (QoS) of network services under certain conditions, since it may modify some traffic characteristics, as delay or jitter, and may also drop packets. As a consequence, the characterization of the buffer is interesting, especially when multimedia flows are transmitted and even more if they transport information with real-time requirements. This work presents a new methodology with the aim of determining the technical and functional characteristics of real buffers (i.e., behaviour, size, limits, and input and output rate) of a network path. It permits the characterization of intermediate buffers of different devices in a network path across the Internet. PMID:25152904

  5. Influence of electrode, buffer gas and control gear on metal halide lamp performance

    International Nuclear Information System (INIS)

    In this paper the influence of electrode composition, buffer gas fill pressure and control gear on the performance of metal halide lamps is investigated. It is shown that pure tungsten electrodes improve lumen maintenance and reduce voltage rise over lamp life. An optimum buffer gas fill pressure condition is discovered which allows for reduced electrode erosion during lamp starting as well as under normal operating conditions. Use of electronic control gear is shown to improve the performance of metal halide lamps

  6. Balance equations can buffer noisy and sustained environmental perturbations of circadian clocks

    OpenAIRE

    Domijan, Mirela; Rand, David A.

    2010-01-01

    We present a new approach to understanding how regulatory networks such as circadian clocks might evolve robustness to environmental fluctuations. The approach is in terms of new balance equations that we derive. We use it to describe how an entrained clock can buffer the effects of daily fluctuations in light and temperature levels. We also use it to study a different approach to temperature compensation where instead of considering a free-running clock, we study temperature buffering of the...

  7. Are capital buffers pro-cyclical? Evidence from Spanish panel data

    OpenAIRE

    Juan Ayuso; Daniel Pérez; Jesús Saurina

    2002-01-01

    In this paper, we analyse the relationship between the Spanish business cycle and the capital buffers held by Spanish commercial and savings banks. We build an incomplete panel of Spanish institutions from 1986 to 2000 –thus covering a complete business cycle– and estimate an equation for the behaviour of capital buffers that includes an indicator of the business cycle. Our findings are fairly robust and quite unequivocal. After controlling for other potential determinants of the surplus capi...

  8. The development and testing of rail-vehicle buffers filled with elastomer spring packages

    OpenAIRE

    Legat, Janko; Gubeljak, Nenad; Predan, Jožef

    2015-01-01

    The decision of the Slovenian Railway Company to modernise the shock absorbing and traction equipment of its existing rolling stock initiated the development of novel spring packages consisting of elastomer-metal-based elements. The crash testing of rail vehicles represents an important part of the testing of spring packages after their installation into buffers. The collision of a loaded rail vehicle with another loaded rail vehicle at a standstill is used to evaluate the capacity of buffers...

  9. Performance analysis of a transfer line with unreliable machines and finite buffers

    OpenAIRE

    Xie, Xiaolan

    1989-01-01

    This paper examines the performance analysis of a transfer line with unreliable machines and finite buffers. All machines have the same processing times. We propose a new decomposition method which decomposes a line into a set of two-machine lines. A sufficient set of equations is established to find performance measures such as production rate and average buffer levels. A simple iterative algorithm is then proposed to solve these equations. We also prove that the set of decomposition equatio...

  10. Compressive behaviour of the soil in buffer zones under different management practices in Finland

    OpenAIRE

    Räty, Mari; Horn, Rainer; Rasa, Kimmo; Yli-Halla, Markku; Pietola, Liisa

    2010-01-01

    Soil structure that favours infiltration is essential for successful functioning of vegetated buffer zones. We measured bulk density, air permeability and precompression stress in a clay soil (Vertic Cambisol) and a sandy loam (Haplic Regosol) in Finland, to identify management-related changes in the physical and mechanical properties in the surface soil of buffer zones. In addition, the impact of texture on these properties was studied at depths down to 180?200 cm. Soil cores (240 cm3) were ...

  11. Hygrothermal modelling of Lime-Hemp concrete used as building material and indoor climate buffering characterization

    OpenAIRE

    Dubois, Samuel; Evrard, Arnaud; Lebeau, Frédéric

    2012-01-01

    Hygroscopic building materials can affect the indoor air by exchanging moisture with it and buffering the ambient humidity variations. The Nordtest protocol and the concomitant Moisture Buffer Value (MBV) parameter definition has been one of the first attempt to characterize this moisture regulation performance. This paper present an attempt to confront this well-established experimental protocol with a mathematical model implemented in the Comsol mul...

  12. A Novel Buffer Layer of Alq3 in Organic Electroluminescent Devices

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Feng; DENG Zhen-Bo; LIANG Chun-Jun; LIN Peng; ZHANG Meng-Xin; XU Deng-Hui

    2004-01-01

    @@ Inserting the Alq3 layer in the ITO/NPB interface as the buffer layer can improve the organic electroluminescent devices. The current density efficiency and power efficiency of the device with the Alq3 buffer layer rises to 6.5 cd/A and 1.21 m/W at the current density of 120 mA/cm2, respectively. The improvement is mostly attributed to the balance of the hole and the electron injections.

  13. Riparian buffer strips as a multifunctional management tool in agricultural landscapes: Introduction to the special collection

    OpenAIRE

    Stutter, M. I.; Chardon, W.J.; B. Kronvang

    2012-01-01

    Catchment riparian areas are considered key zones to target mitigation measures aimed at interrupting the movement of diffuse substances from agricultural land to surface waters. Hence, unfertilized buffer strips have become a widely studied and implemented “edge of field” mitigation measure assumed to provide an effective physical barrier against nitrogen (N), phosphorus (P), and sediment transfer. To ease the legislative process, these buffers are often narrow mandatory strips along streams...

  14. Engineered barrier experiments and analytical studies on coupled thermal - hydraulic - chemical processes in bentonite buffer material

    International Nuclear Information System (INIS)

    It is anticipated that thermal - hydraulic - mechanical - chemical (THMC) processes will be coupled in the bentonite buffer material of a high-level radioactive waste repository. The main contributors to these processes are heat arising from the radioactive decay of the vitrified waste, infiltration of groundwater from the host rock and/or leachate from the cementitious component of the repository, and the consequent increase in swelling pressure and chemical reactions. In order to evaluate these coupled processes in the bentonite buffer material, it is necessary to take steps towards the development of a credible and robust THMC model. The current paper describes the measured data of an engineering-scale coupled THC process experiment and the calculated results of a THC model undergoing development. The coupled experiment used an electric heater, bentonite blocks and a mortar block, subjected to infiltrating water to simulate a high-alkaline porewater derived from the concrete tunnel support seeping into the bentonite buffer material under a thermal gradient provided by the vitrified waste. Temperature and water content of the bentonite buffer material were measured by several sensors continuously for several months. After this time, the buffer material was sampled. The results of mineral analysis of the samples suggested that the precipitate of amorphous hydrate with silica was found in the buffer material in contact with the mortar. The developing THC model simulated C-S-H gel precipitation as a secondary mineral in the exact same locality because of the solution being saturated with respect to portlandite and chalcedony, thereby providing some confidence in the chemical feature of the developing THC model. Some important issues in the future development of the model were also identified, including the concentration of porewater being influenced by vapor movement in the bentonite buffer material due to heating from the vitrified waste and geochemical reactions

  15. Nostalgia buffers the negative impact of low procedural injustice on cooperation

    OpenAIRE

    Van Dijke, M.; Wildschut, Tim; Leunissen, J.M.; Sedikides, Constantine

    2015-01-01

    This research integrates the discrete emotion of nostalgia (a sentimental longing for the past) with relational models of procedural justice. An organizational survey and four experiments demonstrated that nostalgia buffers (i.e., weakens) the deleterious impact of low (compared to high) procedural justice on organizational citizenship behavior (OCB) and cooperation with authorities. Low procedural justice undermined social connectedness with authorities, and nostalgia’s buffering role derive...

  16. Investigation on Characteristics and the Improving Method of Double Loop Optical Buffer

    Institute of Scientific and Technical Information of China (English)

    WANG Yong-Jun; WU Chong-Qing; WANG Zhi; YANG Shuang-Shou; ZHAO Shuang; WANG Ya-Ping; SHU Da; ZHAO Xi

    2009-01-01

    @@ We establish an equivalent cascaded semiconductor optical amplifier system model to analyze the characteristics of the double loop optical buffer (DLOB). The theoretical analysis finds that the performance of the DLOB can be improved by inserted amplifying process in an interval of some cycles. The experiment demonstrates that the buffered cycles can be improved from 20 to 50 and the bit error rate is less than 10-9 by inserting amplifying process in an interval of about 10 cycles.

  17. Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration.

    Science.gov (United States)

    Haukos, David A; Johnson, Lacrecia A; Smith, Loren M; McMurry, Scott T

    2016-10-01

    Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30-60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands. PMID:27423768

  18. Influence of mineral environment on the buffering capacity of casein micelles

    OpenAIRE

    Salaun, Françoise; Mietton, Bernard; Gaucheron, Frederic

    2007-01-01

    The buffering capacity of casein micelle suspensions is a physico-chemical characteristic depending on the mineral and protein composition, on the interactions between these compounds and on the physicochemical environment. In this study, buffering capacity was maximum at pH about 5.2 and was mainly due to the acid-base properties of inorganic phosphate solubilised during acidification and organic phosphate from phosphoserine residues of caseins. Addition of calcium chloride to suspensions of...

  19. Assessment of the buffer-induced setback effects on riparian scenic quality by digital tools

    OpenAIRE

    W-N Xiang

    1998-01-01

    Under a typical riparian landscape structure where a vegetated buffer is sandwiched between a greenway trail and the river bank or lake shore, a trail user's perceptions about riparian scenic quality are influenced by, among other factors, buffer-induced setback effects. As a trail is set back to leave enough space for the vegetated linear area, both the subject and the composition of a trail user's viewshed can change significantly. This may in turn affect his or her perceptions of the lakes...

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

    OpenAIRE

    Diamantidis A. C.; Papadopoulos C. T.

    2004-01-01

    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 ...

  1. Social buffering enhances extinction of conditioned fear responses in male rats.

    Science.gov (United States)

    Mikami, Kaori; Kiyokawa, Yasushi; Takeuchi, Yukari; Mori, Yuji

    2016-09-01

    In social species, the phenomenon in which the presence of conspecific animals mitigates stress responses is called social buffering. We previously reported that social buffering in male rats ameliorated behavioral fear responses, as well as hypothalamic-pituitary-adrenal axis activation, elicited by an auditory conditioned stimulus (CS). However, after social buffering, it is not clear whether rats exhibit fear responses when they are re-exposed to the same CS in the absence of another rat. In the present study, we addressed this issue using an experimental model of extinction. High stress levels during extinction training impaired extinction, suggesting that extinction is enhanced when stress levels during extinction training are low. Therefore, we hypothesized that rats that had received social buffering during extinction training would not show fear responses to a CS, even in the absence of another rat, because social buffering had enhanced the extinction of conditioned fear responses. To test this, we subjected male fear-conditioned rats to extinction training either alone or with a non-conditioned male rat. The subjects were then individually re-exposed to the CS in a recall test. When the subjects individually underwent extinction training, no responses were suppressed in the recall test. Conversely, when the subjects received social buffering during extinction training, freezing and Fos expression in the paraventricular nucleus of the hypothalamus and lateral amygdala were suppressed. Additionally, the effects of social buffering were absent when the recall test was conducted in a different context from the extinction training. The present results suggest that social buffering enhances extinction of conditioned fear responses. PMID:27158024

  2. Buffer Interference with Protein Dynamics: A Case Study on Human Liver Fatty Acid Binding Protein

    OpenAIRE

    Long, Dong; Yang, Daiwen

    2009-01-01

    Selection of suitable buffer types is often a crucial step for generating appropriate protein samples for NMR and x-ray crystallographic studies. Although the possible interaction between MES buffer (2-(N-morpholino)ethanesulfonic acid) and proteins has been discussed previously, the interaction is usually thought to have no significant effects on the structures of proteins. In this study, we demonstrate the direct, albeit weak, interaction between MES and human liver fatty acid binding prote...

  3. Effects of Buffer Size and Shape on Associations between the Built Environment and Energy Balance

    OpenAIRE

    James, Peter; Berrigan, David; Hart, Jaime E; Hipp, J. Aaron; Hoehner, Christine M.; Kerr, Jacqueline; Major, Jacqueline M.; Oka, Masayoshi; Laden, Francine

    2014-01-01

    Uncertainty in the relevant spatial context may drive heterogeneity in findings on the built environment and energy balance. To estimate the effect of this uncertainty, we conducted a sensitivity analysis defining intersection and business densities and counts within different buffer sizes and shapes on associations with self-reported walking and body mass index. Linear regression results indicated that the scale and shape of buffers influenced study results and may partly explain the inconsi...

  4. Final report of the Buffer Mass Test - Volume I: Scope, preparative field work and test arrangement

    International Nuclear Information System (INIS)

    The Buffer Mass Test was conducted in a 30 m long drift at 340 m depth in the Stripa mine, The main objective being to check the predicted functions of certain bentonite-based buffer materials in rock environment. These materials were blocks of highly compacted sodium bentonite placed in large boreholes simulating deposition holes for canisters, and on-site compacted sand/bentonite mixtures used as tunnel backfill. The blocks of bentonite embedded electrical heaters which served to produce heat so as to create conditions similar to those in a repository. The temperature in the initially non-saturated buffer materials was expected to be a function of the water uptake from the rock, which was also assumed to lead to rather high swelling pressures. The recording of these processes and of the moistening of the buffer materials , as well as of the associated build-up of piezometric heads at rock/buffer interfaces, was the major item of the field test. For this purpose the buffer materials and the rock were equipped with a large number of thermal elements, pressure and piezometric cells as well as moisture sensors. The choise of positions and properties of these gauges, which were connected to an effective data acquisition system, was based on predictions that required a careful site documentation with respect to the fracture characteristics and hydrological properties of the surrounding rock. (author)

  5. Alternative buffer material. Status of the ongoing laboratory investigation of reference materials and test package 1

    International Nuclear Information System (INIS)

    Bentonite clay is part of the Swedish KBS-3 design of final repositories for high level radioactive waste. Wyoming bentonite with the commercial name MX-80 (American Colloid Co) has long been the reference for buffer material in the KBS-3 concept. Extending the knowledge base of alternative buffer materials will make it possible to optimize regarding safety, availability and cost. For this reason the field experiment Alternative Buffer Material (ABM) was started at Aespoe Hard Rock Laboratory during 2006. The experiment includes three medium-scale test packages, each consisting of a central steel tube with heaters, and a buffer of compacted clay. Eleven different clays were chosen for the buffers to examine effects of smectite content, interlayer cations and overall iron content. Also bentonite pellets with and without additional quartz are being tested. The buffer in package 1 had been subjected to wetting by formation water and heating for more than two years (at 130 deg C for ∼ 1 year) when it was retrieved and analyzed. The main purposes of the project were to characterise the clays with respect to hydro-mechanical properties, mineralogy and chemical composition and to identify any differences in behaviour or long term stability. The diversity of clays and the heater of steel also make the experiment suitable for studies of iron-bentonite interactions. This report concerns the work accomplished up to now and is not to be treated as any final report of the project

  6. Phosphorus concentrations in soil and subsurface water: a field study among cropland and riparian buffers.

    Science.gov (United States)

    Young, Eric O; Briggs, Russell D

    2008-01-01

    Riparian buffers can be effective at removing phosphorus (P) in overland flow, but their influence on subsurface P loading is not well known. Phosphorus concentrations in the soil, soil solution, and shallow ground water of 16 paired cropland-buffer plots were characterized during 2004 and 2005. The sites were located at two private dairy farms in Central New York on silt and gravelly silt loams (Aeric Endoaqualfs, Fluvaquentic Endoaquepts, Fluvaquentic Eutrudepts, Glossaquic Hapludalfs, and Glossic Hapludalfs). It was hypothesized that P availability (sodium acetate extractable-P) and soil-landscape variability would affect P release to the soil solution and shallow ground water. Results showed that P availability tended to be greater in crop fields relative to paired buffer plots. Soil P was a good indicator of soil solution dissolved ( or =0.45 microm) reactive P (PRP), and dissolved unreactive P (DUP) concentrations in ground water. Soil organic matter and 50-cm depth soil solution DRP in buffers jointly explained 75% of the average buffer ground water DRP variability. Results suggest that buffers were relatively effective at reducing soil solution and shallow ground water DRP concentrations, but their impact on particulate and organic P in ground water was less clear. PMID:18178879

  7. 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

    2015-06-01

    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. PMID:26015575

  8. DETERMINATION OF BUFFER SIZE IN SINGLE AND MULTI ROW FLEXIBLE MANUFACTURING SYSTEMS THROUGH SIMULATION

    Directory of Open Access Journals (Sweden)

    Naveen Ravela

    2011-05-01

    Full Text Available This paper presents the determination of buffer size for machines in single and multi row Flexible Manufacturing System (FMS for the best layout obtained by genetic algorithm (GA throughsimulation. To maximize the operating performance of FMS, many parameters must be considered, including the part types, sequencing, cost of transport between workstations, distance between machinesand buffer sizes. Of the various critical factors, following three are considered for analysis: (1 minimizing the buffer size (2 minimizing the blocking and (3 maximizing the machine utilization.Simulation enables more efficient planning of the whole FMS, easy modifications before implementation on the real system. The software package FLEXSIM is used to develop the simulation model. A model ofa optimum layout FMS obtained by GA that may contain a number of machines, input and output buffers, capturing part types flow quantities, part routes, from the database and AGV’s used as a meansof transport, is built by FLEXSIM software. Analysis is done on the model to determine the optimum buffer size for the machines. Thus by performing simulation on the model optimum buffer size in theindividual rows are established.

  9. A Study on Establishment of Buffer Zone of Radioactive Waste Repository

    International Nuclear Information System (INIS)

    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.

  10. Biophysical stability of hyFc fusion protein with regards to buffers and various excipients.

    Science.gov (United States)

    Lim, Jun Yeul; Kim, Nam Ah; Lim, Dae Gon; Eun, Chang-yong; Choi, Donghoon; Jeong, Seong Hoon

    2016-05-01

    A novel non-cytolytic hybrid Fc (hyFc) with an intact Ig structure without any mutation in the hyFc region, was developed to construct a long-acting agonistic protein. The stability of interleukin-7 (IL-7) fused with the hyFc (GXN-04) was evaluated to develop early formulations. Various biophysical methods were utilized and three different buffer systems with various pH ranges were investigated including histidine-acetate, sodium citrate, and tris buffers. Various excipients were incorporated into the systems to obtain optimum protein stability. Two evident thermal transitions were observed with the unfolding of IL-7 and hyFc. The Tm and ΔH increased with pH, suggesting increased conformational stability. Increased Z-average size with PDI and decreased zeta potential with pH increase, with the exception of tris buffer, showed aggregation issues. Moreover, tris buffer at higher pH showed aggregation peaks from DLS. Non-ionic surfactants were effective against agitation by outcompeting protein molecules for hydrophobic surfaces. Sucrose and sorbitol accelerated protein aggregation during agitation, but exhibited a protective effect against oxidation, with preferential exclusion favoring the compact states of GXN-04. The stability of GXN-04 was varied by basal buffers and excipients, hence the buffers and excipients need to be evaluated carefully to achieve the maximum stability of proteins. PMID:26851357

  11. 'Trophic whales' as biotic buffers: weak interactions stabilize ecosystems against nutrient enrichment.

    Science.gov (United States)

    Schwarzmüller, Florian; Eisenhauer, Nico; Brose, Ulrich

    2015-05-01

    Human activities may compromise biodiversity if external stressors such as nutrient enrichment endanger overall network stability by inducing unstable dynamics. However, some ecosystems maintain relatively high diversity levels despite experiencing continuing disturbances. This indicates that some intrinsic properties prevent unstable dynamics and resulting extinctions. Identifying these 'ecosystem buffers' is crucial for our understanding of the stability of ecosystems and an important tool for environmental and conservation biologists. In this vein, weak interactions have been suggested as stabilizing elements of complex systems, but their relevance has rarely been tested experimentally. Here, using network and allometric theory, we present a novel concept for a priori identification of species that buffer against externally induced instability of increased population oscillations via weak interactions. We tested our model in a microcosm experiment using a soil food-web motif. Our results show that large-bodied species feeding at the food web's base, so called 'trophic whales', can buffer ecosystems against unstable dynamics induced by nutrient enrichment. Similar to the functionality of chemical or mechanical buffers, they serve as 'biotic buffers' that take up stressor effects and thus protect fragile systems from instability. We discuss trophic whales as common functional building blocks across ecosystems. Considering increasing stressor effects under anthropogenic global change, conservation of these network-intrinsic biotic buffers may help maintain the stability and diversity of natural ecosystems. PMID:25420573

  12. Palladium buffer-layered high performance ionic polymer–metal composites

    International Nuclear Information System (INIS)

    A new IPMC fabrication method—that is not a repetitive reduction processes—and a new supporting electrode material that is responsible for this procedure are described in this paper. A palladium metal, acting as a buffer layer, was deposited before plating the platinum electrode in order to articulate the surface morphology and the interfacial effect between the electrode and the membrane. The platinum layer was sequentially grown using an electroless chemical deposition on a palladium buffer layer on the polymer membrane. The surface morphology and conductivity of the electrode were enhanced by depositing a buffer layer. Under the same applied voltage, when compared to IPMCs without a buffer layer, the IPMCs with a palladium buffer layer showed a greater bending tendency and had a higher blocking force. The results also indicated that such IPMCs do not exhibit the back relaxation phenomenon under a sustained DC voltage. The amplitude of the transduction signal produced by the Pt/Pd IPMC shows much larger amplitude of the signal produced by the Pt IPMC. Thus, the IPMC with a palladium buffer layer has the potential for future applications as an actuator and transducer

  13. Alternative buffer material. Status of the ongoing laboratory investigation of reference materials and test package 1

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Daniel [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Dueck, Ann; Nilsson, Ulf; Olsson, Siv; Sanden, Torbjoern [Clay Technology AB, Lund (Sweden); Lydmark, Sara; Jaegerwall, Sara; Pedersen, Karsten [Microbial Analytics Sweden AB, Moelnlycke (Sweden); Hansen, Staffan [LTH Lund Univ., Lund (Sweden)

    2011-07-15

    Bentonite clay is part of the Swedish KBS-3 design of final repositories for high level radioactive waste. Wyoming bentonite with the commercial name MX-80 (American Colloid Co) has long been the reference for buffer material in the KBS-3 concept. Extending the knowledge base of alternative buffer materials will make it possible to optimize regarding safety, availability and cost. For this reason the field experiment Alternative Buffer Material (ABM) was started at Aespoe Hard Rock Laboratory during 2006. The experiment includes three medium-scale test packages, each consisting of a central steel tube with heaters, and a buffer of compacted clay. Eleven different clays were chosen for the buffers to examine effects of smectite content, interlayer cations and overall iron content. Also bentonite pellets with and without additional quartz are being tested. The buffer in package 1 had been subjected to wetting by formation water and heating for more than two years (at 130 deg C for {approx} 1 year) when it was retrieved and analyzed. The main purposes of the project were to characterise the clays with respect to hydro-mechanical properties, mineralogy and chemical composition and to identify any differences in behaviour or long term stability. The diversity of clays and the heater of steel also make the experiment suitable for studies of iron-bentonite interactions. This report concerns the work accomplished up to now and is not to be treated as any final report of the project.

  14. 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. PMID:25744820

  15. The Determination of Buffering Capacity of Some Ruminant's Feedstuffs and their Cumulative Effects on TMR Ration

    Directory of Open Access Journals (Sweden)

    A. Moharrery

    2007-01-01

    Full Text Available Two experiments have been conducted in order to investigate the buffering capacity of some ruminant's feedstuffs and their additivity to calculate ration buffering capacity as a tools for feed formulation. The first experiment was performed with different types (65 samples of feedstuffs to determine the Buffering Capacity (BC and Buffer Value Index (BVI. For investigation of cumulative effects of buffering capacity or buffer value index, 6 Total Mixed Rations (TMR for dairy cow and other six TMR for sheep were formulated using the feedstuffs with known BC or BVI. The calculated and analyzed values were compared using paired t-test. In the second experiment rumen fluid pH was measured using 5 simple rations on 5 adult sheep and correlation was calculated between rumen fluid pH and fiber or ash content of the diets. The analyzed BC and BVI for all the TMRs appeared to be lower than the values calculated from these variables, for individual feedstuffs (p0.05. No significant (p>0.05 correlation has been found between ruminal fluid pH and dietary components.

  16. A Better Memoryless Online Algorithm for FIFO Buffering Packets with Two Values

    CERN Document Server

    Li, Fei

    2010-01-01

    We consider scheduling weighted packets in a capacity-bounded buffer. In this model, there is a buffer with a limited capacity B such that at any time, the buffer cannot accommodate more than B packets. Packets arrive over time. Each packet has a non-negative real value. Packets do not expire and they leave the buffer only because either we send them or we drop them. The packets that have left the buffer will not be reconsidered for delivery any more. In each time step, at most one packet in the buffer can be sent. The order in which the packets are sent should comply with the order of their arriving time. The objective is to maximize the total value of the packets sent in an online manner. In this paper, we study a variant of this model in which packets have value 1 or alpha > 1. We present a deterministic memoryless 1.305-competitive algorithm, improving the previously best known result 1.544 (Kesselman and Mansour. Journal of Algorithms 2003). In designing our algorithm, we apply a few new ideas. We do not...

  17. Operation voltage behavior of organic light emitting diodes with polymeric buffer layers doped by weak electron acceptor

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Hyeon Soo; Cho, Sang Hee [Department of Information Display and Advanced Display Research Center, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Seo, Jaewon; Park, Yongsup [Department of Physics, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Suh, Min Chul, E-mail: mcsuh@khu.ac.kr [Department of Information Display and Advanced Display Research Center, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

    2013-11-01

    We present polymeric buffer materials based on poly[2,7-(9,9-dioctyl-fluorene)-co-(1,4-phenylene -((4-sec-butylphenyl)imino)-1,4-phenylene)] (TFB) for highly efficient solution processed organic light emitting diodes (OLEDs). Doped TFB with 9,10-dicyanoanthracene, a weak electron acceptor results in significant improvement of current flow and driving voltage. Maximum current- and power-efficiency value of 12.6 cd/A and 18.1 lm/W are demonstrated from phosphorescent red OLEDs with this doped polymeric anode buffer system. - Highlights: • Polymeric buffer materials for organic light emitting diodes (OLEDs). • Method to control hole conductivity of polymeric buffer layer in OLED device. • Enhanced current density of buffer layers upon 9,10-dicyanoanthracene (DCA) doping. • Comparison of OLED devices having polymeric buffer layer with or without DCA. • Effect on operating voltage by doping DCA in the buffer layer.

  18. Buffer-Gas Cooling of a Single Ion in a Multipole Radio Frequency Trap Beyond the Critical Mass Ratio

    Science.gov (United States)

    Höltkemeier, Bastian; Weckesser, Pascal; López-Carrera, Henry; Weidemüller, Matthias

    2016-06-01

    We theoretically investigate the dynamics of a trapped ion immersed in a spatially localized buffer gas. For a homogeneous buffer gas, the ion's energy distribution reaches a stable equilibrium only if the mass of the buffer gas atoms is below a critical value. This limitation can be overcome by using multipole traps in combination with a spatially confined buffer gas. Using a generalized model for elastic collisions of the ion with the buffer-gas atoms, the ion's energy distribution is numerically determined for arbitrary buffer-gas distributions and trap parameters. Three regimes characterized by the respective analytic form of the ion's equilibrium energy distribution are found. Final ion temperatures down to the millikelvin regime can be achieved by adiabatically decreasing the spatial extension of the buffer gas and the effective ion trap depth (forced sympathetic cooling).

  19. Operation voltage behavior of organic light emitting diodes with polymeric buffer layers doped by weak electron acceptor

    International Nuclear Information System (INIS)

    We present polymeric buffer materials based on poly[2,7-(9,9-dioctyl-fluorene)-co-(1,4-phenylene -((4-sec-butylphenyl)imino)-1,4-phenylene)] (TFB) for highly efficient solution processed organic light emitting diodes (OLEDs). Doped TFB with 9,10-dicyanoanthracene, a weak electron acceptor results in significant improvement of current flow and driving voltage. Maximum current- and power-efficiency value of 12.6 cd/A and 18.1 lm/W are demonstrated from phosphorescent red OLEDs with this doped polymeric anode buffer system. - Highlights: • Polymeric buffer materials for organic light emitting diodes (OLEDs). • Method to control hole conductivity of polymeric buffer layer in OLED device. • Enhanced current density of buffer layers upon 9,10-dicyanoanthracene (DCA) doping. • Comparison of OLED devices having polymeric buffer layer with or without DCA. • Effect on operating voltage by doping DCA in the buffer layer

  20. The effect of the carbon nanotube buffer layer on the performance of a Li metal battery

    Science.gov (United States)

    Zhang, Ding; Zhou, Yi; Liu, Changhong; Fan, Shoushan

    2016-05-01

    Lithium (Li) metal is one of the most promising candidates as an anode for the next-generation energy storage systems because of its high specific capacity and lowest negative electrochemical potential. But the growth of Li dendrites limits the application of the Li metal battery. In this work, a type of modified Li metal battery with a carbon nanotube (CNT) buffer layer inserted between the separator and the Li metal electrode was reported. The electrochemical results show that the modified batteries have a much better rate capability and cycling performance than the conventional Li metal batteries. The mechanism study by electrochemical impedance spectroscopy reveals that the modified battery has a smaller charge transfer resistance and larger Li ion diffusion coefficient during the deposition process on the Li electrode than the conventional Li metal batteries. Symmetric battery tests show that the interfacial behavior of the Li metal electrode with the buffer layer is more stable than the naked Li metal electrode. The morphological characterization of the CNT buffer layer and Li metal lamina reveals that the CNT buffer layer has restrained the growth of Li dendrites. The CNT buffer layer has great potential to solve the safety problem of the Li metal battery.Lithium (Li) metal is one of the most promising candidates as an anode for the next-generation energy storage systems because of its high specific capacity and lowest negative electrochemical potential. But the growth of Li dendrites limits the application of the Li metal battery. In this work, a type of modified Li metal battery with a carbon nanotube (CNT) buffer layer inserted between the separator and the Li metal electrode was reported. The electrochemical results show that the modified batteries have a much better rate capability and cycling performance than the conventional Li metal batteries. The mechanism study by electrochemical impedance spectroscopy reveals that the modified battery has a

  1. Effect of Tris-acetate buffer on endotoxin removal from human-like collagen used biomaterials

    International Nuclear Information System (INIS)

    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

  2. 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)

    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

  3. 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

  4. Runtime buffer management to improve the performance in irregular Network-on-Chip architecture

    Indian Academy of Sciences (India)

    Umamaheswari S; Meganathan D; Raja Paul Perinbam J

    2015-06-01

    This paper presents a heterogeneous adaptable router to reduce latency in irregular mesh Network-on-Chip (NoC) architectures. Regular mesh-based NoC architecture may become irregular due to variable sized IPs and needs new routing algorithms to ensure throughput. Therefore, an irregular NoC mesh is considered and an adaptive algorithm is used for routing. The performance measures such as through-put, latency, and bandwidth are defined at design time to guarantee the performance of NoC. However, if the application has to change its communication pattern, parameters set at design time (say buffer size) may result in large area and power consumption or increased latency. Routers with large input buffers improve the efficiency of NoC communication, but they incur excessive power dissipation and hardware overheads. Routers with small buffers reduce power consumption, but result in high latency. In the proposed NoC router, input buffers can be dynamically allocated, thereby, latency can be reduced. In a 4 × 4 irregular mesh NoC with a buffer depth of 4 slots, 20% reduction in latency and 9% increase in throughput are attained using dynamic buffer allocation. An 8 × 8 irregular mesh NoC with the proposed router is exposed to the synthetic traffics like uniform, bit complement, tornado and hotspot traffics and it offered a 30.42% reduction in overall average latency and 18.33% increase in overall saturation throughput. The proposed router outperformed the static router by 22.63% less average latency for E3S benchmark applications. For the same performance, maximum of 55% reduction in buffer requirement and 53% less power consumption is achieved.

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

    International Nuclear Information System (INIS)

    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

  6. 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

  7. Enhanced transpiration by riparian buffer trees in response to advection in a humid temperate agricultural landscape

    Science.gov (United States)

    Hernandez-Santana, V.; Asbjornsen, H.; Sauer, T.; Isenhart, T.; Schilling, K.; Schultz, Ronald

    2011-01-01

    Riparian buffers are designed as management practices to increase infiltration and reduce surface runoff and transport of sediment and nonpoint source pollutants from crop fields to adjacent streams. Achieving these ecosystem service goals depends, in part, on their ability to remove water from the soil via transpiration. In these systems, edges between crop fields and trees of the buffer systems can create advection processes, which could influence water use by trees. We conducted a field study in a riparian buffer system established in 1994 under a humid temperate climate, located in the Corn Belt region of the Midwestern U.S. (Iowa). The goals were to estimate stand level transpiration by the riparian buffer, quantify the controls on water use by the buffer system, and determine to what extent advective energy and tree position within the buffer system influence individual tree transpiration rates. We primarily focused on the water use response (determined with the Heat Ratio Method) of one of the dominant species (Acer saccharinum) and a subdominant (Juglans nigra). A few individuals of three additional species (Quercus bicolor, Betula nigra, Platanus occidentalis) were monitored over a shorter time period to assess the generality of responses. Meteorological stations were installed along a transect across the riparian buffer to determine the microclimate conditions. The differences found among individuals were attributed to differences in species sap velocities and sapwood depths, location relative to the forest edge and prevailing winds and canopy exposure and dominance. Sapflow rates for A. saccharinum trees growing at the SE edge (prevailing winds) were 39% greater than SE interior trees and 30% and 69% greater than NW interior and edge trees, respectively. No transpiration enhancement due to edge effect was detected in the subdominant J. nigra. The results were interpreted as indicative of advection effects from the surrounding crops. Further, significant

  8. Modular approaches to the control of diffuse agricultural pollution: buffer zones, bioreactors, ditches and ponds

    Science.gov (United States)

    Hawkins, J. M. B.; Blackwell, M. S. A.; Granger, S.; Chadwick, D.; Haygarth, P.; Bol, R.

    2009-04-01

    Despite the abundance of literature reporting both riparian and non-riparian buffer strip performance in the control of diffuse pollutants from agriculture, the spatial and temporal mechanistics of the processes involved are poorly understood. As a result, buffer zones have often been implemented incorrectly and have failed to deliver the benefits expected of them. One of the main challenges with buffer zone effectiveness has been found to be their by-passing by the passage of polluted water through sub-surface drains which in many regions of the UK has regularly been shown to greatly limit their value with regard to nutrient control [MAFF report, Leeds-Harrison 1996]. In addition, little work has been carried out on the role of additional, complementary structural buffering methods such as managed ditches and ponds, which may provide more benefits, especially if used either alongside or instead of the more conventional use of buffer strips. This paper describes a new 5 year Defra funded project*, which is using a multi-scaled approach to understand the abiotic and biotic drivers of the short-term and ‘long-term' effectiveness of conventional grassed buffer strips. At the field scale, we are using high resolution monitoring methods to compare the effectiveness of other mitigation methods including buffer strips enhanced with subsurface bioreactors, managed ditches, and ponds, to control a range of water pollutants and hydrology. Each of the mitigation methods is being investigated both individually, and as part of a strategic modular network of mitigation methods in a purposely constructed and replicated experimental site. References Leeds-Harrison , P. B., Quinton, J. N., Walker, M., Harrison, K. S., Gowing, D. G., Tyrrel, S. F., Morris, J., Mills, J., and Harrod, T. (1996). "Buffer zones in headwater catchments ". MAFF-English Nature Buffer Zone project CSA 2285, Cranfield University, Silsoe, Bedford, UK. *Link to Defra website: http://randd.defra.gov.uk

  9. Effect of buffer layer on the voltage responsivity of the pyroelectric thermal sensors prepared with PZT ceramics

    Science.gov (United States)

    Lee, Moon-Ho; Hwang, Ha R.; Bae, Seong-Ho

    1997-08-01

    The pyroelectric thermal detectors were prepared with lead zirconate titanate (PZT) ceramics, where a signal electrode had a structure of Au/metallic buffer/(PZT ceramic). The effect of buffer layer on the voltage responsivity was investigated with a response to step signal, taken by dynamic pyroelectric measurement. Pyroelectric ceramic wafer was prepared by mixed oxide technique. Au layer (thickness: 50 nm) and metallic buffers (thickness: 0 - 20 nm) of Cr, NiCr (80/20), and Ti were prepared by dc magnetron sputtering. In order to improve the light absorptivity, an Au-black was coated on Au signal electrode by thermal evaporation. At steady state, the output voltage (Vo) was decreased with increasing chopping frequency in the range of 1 - 100 Hz. A sensor without buffer showed the severe time-drift and instability in the output signal. However, the sensors with buffer layer showed the stable outputs. For step radiations, rising time (tp), peak voltage (Vp), and initial slope (k) of the output voltage were dependent upon the thickness and materials of buffer layer. The mechanical and electrical contacts between Au electrode and PZT ceramics were improved by inserting the metallic buffer layer. Considering the characteristics of the output voltage, the optimum thickness of buffer layer was about 15 - 20 nm, and the sensors with Ti buffer of 15 - 20 nm in thickness showed the good detectivity. Therefore, the stability and reliability of the thermal sensors could be improved by use of appropriate buffer layer.

  10. Deposition of high-level radioactive waste products in bore-holes with buffer substance

    International Nuclear Information System (INIS)

    The present investigation comprised a compilation of available literature data concerning the possible use of clayey masses as buffer substances in bore-holes (in rock) with canisters containing radioactive waste products. The aim was to find a suitable composition of the buffer mass and to recommend a suitable storing technique. The criteria concerning the function of the buffer substance were: Sufficient mechanical supporting power, suitable mechanical properties, prevention of free circulation of ground water, ion-adsorption ability, sufficiently good heat conduction properties. These criteria suggest that a buffer substance containing Na-montmorillonite would be suitable. Literature studies and own experience show that montmorillonite is permanently stable at 100 degrees C temperature and 5 MPa pressure when pH is within the range of 6.5-10 while quartz is stable at pH <9. The authors conclude that the suggested principle of storing the canisters in sealed bore-holes filled with a 10 percent bentonite/90 percent quartz (silt, sand) mass is suitable provided that the tunnel system, from which the holes are bored, is sealed with a dense buffer mass consisting of quartz (silt, sand) and 20-50 percent bentonite powder. (author)

  11. DNA amplification fingerprinting using 10 x polymerase chain reaction buffer with ammonium sulfate for human identification

    International Nuclear Information System (INIS)

    The polymerase chain reaction (PCR) - based DNA amplification fingerprinting (DAF) or randomly amplified polymorphic DNA (RAPD) is based on a strategy using a single arbitrary oligonucleotide primer to generate anonymous amplification of genomic DNA. On this basic strategy, in this study, we aimed to test individual differences and usefulness of 2 basic primers (5-CGCGCCGG-3 and 5-TGCCGAGCTG-3) and examined whether there is a positive effect on results of 10 x PCR buffer with ammonium sulfate. A new approach in DNA fingerprinting, 10 x PCR buffer with ammonium sulfate, is presented in the study. Primers with single 8 and 10 nucleotides in length and 2 different PCR buffers with or without ammonium sulfate were used to identify 135 volunteers with no blood relationship. This study was carried out at the Pharmacology Laboratory, University of Gaziantep, School of Medicine, Turkey between 1999 and 2000. An average of 10 major bands representing 500-1500 base pair (bp) in length was determined as amplified DNA products on standard agarose gels for these volunteers. The use of ammonium sulfate in 10 x PCR buffers has increased to 92% success ratio of individual difference obtained from the 8 nucleotides primer. With this study, more reliable results can be obtained by using ammonium sulfate in 10 x PCR buffers. (author)

  12. In vivo predictive dissolution: transport analysis of the CO2 , bicarbonate in vivo buffer system.

    Science.gov (United States)

    Krieg, Brian J; Taghavi, Seyed Mohammad; Amidon, Gordon L; Amidon, Gregory E

    2014-11-01

    Development of an oral in vivo predictive dissolution medium for acid drugs with a pKa in the physiological range (e.g., Biopharmaceutics Classification System Class IIa) requires transport analysis of the complex in vivo CO2 /bicarbonate buffering system. In this report, we analyze this buffer system using hydrodynamically defined rotating disk dissolution. Transport analysis of drug flux was predicted using the film model approach of Mooney et al based on equilibrium assumptions as well as accounting for the slow hydration reaction, CO2 + H2 O → H2 CO3 . The accuracy of the models was compared with experimentally determined results using the rotating disk dissolution of ibuprofen, indomethacin, and ketoprofen. The equilibrium and slow hydration reaction rate models predict significantly different dissolution rates. The experimental results are more accurately predicted by accounting for the slow hydration reaction under a variety of pH and hydrodynamic conditions. Although the complex bicarbonate buffering system requires further consideration given its dynamic nature in vivo, a simplifying irreversible reaction (IRR) transport analysis accurately predicts in vitro rotating disk dissolution rates of several carboxylic acid drugs. This IRR transport model provides further insight into bicarbonate buffer and can be useful in developing more physiologically relevant buffer systems for dissolution testing. PMID:25212721

  13. The effect of the carbon nanotube buffer layer on the performance of a Li metal battery.

    Science.gov (United States)

    Zhang, Ding; Zhou, Yi; Liu, Changhong; Fan, Shoushan

    2016-06-01

    Lithium (Li) metal is one of the most promising candidates as an anode for the next-generation energy storage systems because of its high specific capacity and lowest negative electrochemical potential. But the growth of Li dendrites limits the application of the Li metal battery. In this work, a type of modified Li metal battery with a carbon nanotube (CNT) buffer layer inserted between the separator and the Li metal electrode was reported. The electrochemical results show that the modified batteries have a much better rate capability and cycling performance than the conventional Li metal batteries. The mechanism study by electrochemical impedance spectroscopy reveals that the modified battery has a smaller charge transfer resistance and larger Li ion diffusion coefficient during the deposition process on the Li electrode than the conventional Li metal batteries. Symmetric battery tests show that the interfacial behavior of the Li metal electrode with the buffer layer is more stable than the naked Li metal electrode. The morphological characterization of the CNT buffer layer and Li metal lamina reveals that the CNT buffer layer has restrained the growth of Li dendrites. The CNT buffer layer has great potential to solve the safety problem of the Li metal battery. PMID:27181758

  14. A Strategy to enable Prefix of Multicast VoD through dynamic buffer allocation

    CERN Document Server

    nair, T R GopalaKrishnan

    2010-01-01

    In this paper we have proposed a dynamic buffer allocation algorithm for the prefix, based on the popularity of the videos. More cache blocks are allocated for most popular videos and a few cache blocks are allocated for less popular videos. Buffer utilization is also maximized irrespective of the load on the Video-on-Demand system. Overload can lead the server getting slowed down. By storing the first few seconds of popular video clips, a multimedia local server can shield the users from the delay, throughput, and loss properties of the path between the local server and the central server. The key idea of controlled multicast is used to allow clients to share a segment of a video stream even when the requests arrive at different times. This dynamic buffer allocation algorithm is simulated and its performance is evaluated based on the buffer utilization by multimedia servers and average buffer allocation for the most popular videos. Our simulation results shows efficient utilization of network bandwidth and r...

  15. Perpendicular magnetization of CoFeB on top of an amorphous buffer layer

    International Nuclear Information System (INIS)

    Perpendicular magnetic anisotropy was observed in sputtered FeZr/CoFeB/MgO multilayers. A thin paramagnetic amorphous FeZr layer was used as a buffer layer and perpendicular anisotropy was obtained by annealing the samples without an external magnetic field. The critical CoFeB thickness for perpendicular anisotropy was 1.8 nm; the anisotropy changes from out-of-plane to in-plane as the CoFeB thickness increases beyond this point. Perpendicular anisotropy was also enhanced when a Ta layer was capped on top of the MgO layer. The amorphous buffer provided better perpendicular anisotropy than previously reported Ta buffer, and it may be applied to perpendicular magnetization MRAM devices where good uniformity of tunnel junctions is required. - Highlights: • Perpendicular magnetic anisotropy (PMA) of buffer/CoFeB/MgO was investigated. • The PMA was enhanced by using an amorphous buffer. • The PMA of the CoFeB layer was maintained up to 1.8 nm. • Ta capping layer further improved the PMA by 40%

  16. H{sub 2}-dilution vs. buffer layers for increased V{sub oc}

    Energy Technology Data Exchange (ETDEWEB)

    Platz, R.; Fischer, D.; Hof, C.; Dubail, S.; Meier, J.; Kroll, U.; Shah, A. [Univ. de Neuchatel (Switzerland). Inst. de Microtechnique

    1996-12-31

    Hydrogen dilution and buffer layers, as two ways to obtain higher V{sub oc} values in a-Si:H p-i-n solar cells, are directly compared in the present study. Special emphasis is laid on stability against light soaking. H{sub 2}-dilution in combination with lower substrate temperature yields higher V{sub oc} values and better stability as compared to buffer layers. However, light absorption is decreased due to the increased gap in H{sub 2}-diluted cells. The stability of buffer layer cells can remarkably be ameliorated by boron doping and H{sub 2}-dilution of the a-SiC:H buffer layer. However, stabilized efficiency is higher for optimized diluted cells than for cells with a buffer layer. An a-Si/a-Si stacked cell with a graded dilution for both cells yielded 10% initial efficiency with 17% relative degradation. Diluted a-Si:H cells at lower temperature become specially interesting in combination with a microcrystalline bottom cell. For such a micromorph tandem cell the authors obtained 11.4% initial efficiency.

  17. Investigation on the Morphology of Precipitated Chemicals from te Buffer on Solid Substrates

    Science.gov (United States)

    Wang, Huabin; Zhang, Lijuan; Zhang, Feng; An, Hongjie; Chen, Shimou; Li, Hai; Wang, Peng; Wang, Xinyang; Wang, Yang; Yang, Haijun

    Buffer is often involved in the biological studies on a surface with the scanning probe microscopy and the remnant of the salts of buffer may affect the correct interpretation of the experimental results. However, the knowledge on the performance of chemicals of buffer on a substrate is still very poor. TE solution (Tris-HCl, NaCl, and ethylene diamine tetraacetic acid (EDTA)) is a widely used buffer in stocking biological molecules. Herein, we report the performance of the precipitated chemicals from TE solution on two typical substrates with several commonly used sample preparation methods. The results showed that the chemicals in TE solution could self-organize into parallel nanofilaments on hydrophobic highly oriented pyrolitic graphite (HOPG) surface by blotting the shortly incubated solution droplet from the substrate or by drying the diluted solution droplet naturally. In contrast, no such special structures were observed on hydrophilic mica using the same methods. By imaging in TE solutions, no special structures were found on either the HOPG or the mica. Moreover, the effects of the concentration of chemicals of TE buffer on the morphology of precipitated chemicals were also investigated.

  18. DROP TAIL AND RED QUEUE MANAGEMENT WITH SMALL BUFFERS:STABILITY AND HOPF BIFURCATION

    Directory of Open Access Journals (Sweden)

    Ganesh Patil

    2011-06-01

    Full Text Available There are many factors that are important in the design of queue management schemes for routers in the Internet: for example, queuing delay, link utilization, packet loss, energy consumption and the impact of router buffer size. By considering a fluid model for the congestion avoidance phase of Additive Increase Multiplicative Decrease (AIMD TCP, in a small buffer regime, we argue that stability should also be a desirable feature for network performance. The queue management schemes we study are Drop Tail and Random Early Detection (RED. For Drop Tail, the analytical arguments are based on local stability and bifurcation theory. As the buffer size acts as a bifurcation parameter, variations in it can readily lead to the emergence of limit cycles. We then present NS2 simulations to study the effect of changing buffer size on queue dynamics, utilization, window size and packet loss for three different flow scenarios. The simulations corroborate the analysis which highlights that performance is coupled with the notion of stability. Our work suggests that, in a small buffer regime, a simple Drop Tail queue management serves to enhance stability and appears preferable to the much studied RED scheme.

  19. Deposition and characterization of (Zn,Mg)O buffer layers on CIGSSe thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hussmann, Benjamin; Erfurth, Felix; Schoell, Achim [Universitaet Wuerzburg (Germany). Experimentelle Physik II; Niesen, Thomas; Palm, Joerg [Avancis GmbH, Muenchen (Germany); Grimm, Alexander [Hahn-Meitner-Institut Berlin (Germany); Umbach, Eberhard [Universitaet Wuerzburg (Germany). Experimentelle Physik II; Forschungszentrum Karlsruhe (Germany)

    2008-07-01

    (Zn, Mg)O buffer layers on Cu(In,Ga)(S,Se){sub 2}(CIGSSe) thin film solar cells are promising alternatives to CdS buffer layers by featuring comparable efficiencies, better environmental compatibility and the possibility to implement the deposition process into a vacuum processing line. The (Zn,Mg)O buffer layers are deposited by radio frequency magnetron co-sputtering from two separate ZnO and MgO ceramic sputter targets to control the Mg-content and therefore the band gap of the buffer layer. In our experimental setup the sputter preparation chamber is connected with a UHV analysis system which allows in-situ characterization with X-ray photoelectron spectroscopy (XPS). The interface between the absorber and the buffer layer is believed to have a major influence on the cell efficiency and is thus of particular interest in this work. This interface has been investigated during layer deposition by sequentially interrupting the sputter process and performing XPS scans. We observed island growth of (Zn,Mg)O on CIGSSe and a strong oxidation of the absorber surface induced by the deposit. In order to complement the chemical and electronic information with structural data, energy dispersive X-ray analysis, X-ray diffraction, and scanning electron microscopy have been applied.

  20. Riparian buffer project : annual report for the period April 1, 2001 to March 31, 2002.; ANNUAL

    International Nuclear Information System (INIS)

    This project implements riparian buffer systems in the Mid-Columbia, addressing limiting factors identified in the Fifteen mile Subbasin Summary, June 30, 2000. The project is providing the technical planning support needed to implement at least 36 riparian buffer system contracts on approximately 872 acres covering an estimated 40 miles of anadromous fish streams over a three year period. In the first year of implementation, 26 buffer contracts were established on 25-26 miles of stream. This nearly doubled the annual goal. Buffer widths averaged 83 ft. on each side of the stream. Implementation included prescribed plantings, fencing, and related practices. Actual implementation costs, lease payments, and maintenance costs are borne by existing USDA programs: Conservation Reserve and Conservation Reserve Enhancement Programs. The lease period of each contract may vary between 10 to 15 years. During this year the average was 14.5 years. The total value of contracts established this year is$1,491,235 compared with$64,756 in BPA contract costs to provide the technical support needed to get the contracts implemented. This project provides technical staffing to conduct assessments and develop plans to help keep pace with the growing backlog of potential riparian buffer projects. Word of mouth from satisfied customers has brought in many new sign-ups during the year. More than half of the contracts this year have been done in the Hood and Fifteen mile sub-basins with additional contracts in adjacent sub-basins