WorldWideScience

Sample records for strong buffering capacity

  1. Workshop on moisture buffer capacity

    DEFF Research Database (Denmark)

    2003-01-01

    Summary report of a Nordtest workshop on moisture buffer capacity held at Copenhagen August 21-22 2003......Summary report of a Nordtest workshop on moisture buffer capacity held at Copenhagen August 21-22 2003...

  2. Chemical buffering capacity of clay rock

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  3. 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.

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

    Science.gov (United States)

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

    2013-01-01

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

  5. Moisture buffer capacity of different insulation materials

    DEFF Research Database (Denmark)

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

    2004-01-01

    There is an increasing focus on the possibilities of utilizing the absorptive ability of porous materials to create passive control of humidity variations in the indoor air. These variations result in peaks in the indoor air humidity due to moisture production, or in the exterior building envelope...... 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...

  6. 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

    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 effect of interior walls of cellular concrete and plaster board constructions. For the cellular concrete...... of the changes of moisture content in specimens of the wall composites exposed to the same environment. It was found that the finishes had a big impact on the buffer performance of the underlying materials. Even though the untreated cellular concrete had a very high buffer capacity, the effect was strongly...

  7. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture*

    Science.gov (United States)

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

    2015-01-01

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

  8. A high capacity FASTBUS multiple event buffer

    International Nuclear Information System (INIS)

    Appel, J.A.; Farr, W.D.; Kaplan, D.M.; Levit, L.B.; Napier, T.M.

    1985-01-01

    We have developed a front-end data acquisition and event buffering memory. This single-width FASTBUS module has a capacity of 256K X 32 bits plus parity. The module is dual ported, and its front panel ECLport accepts data at up to 20 MB/sec. It may also be written to and read from as a standard FASTBUS Slave. The module records events as variable length records. Each record is accepted or rejected via front panel control signal. Circuitry to automate FASTBUS record readout and record skip is provided. In its ''linear'' mode, the module may be used as a single pass list. Alternatively, in the ''circular'' mode, the module's internal read pointer can follow its write pointer continuously around the memory. Circular mode is well suited to handling of a continuous data stream. Modules may be linked for larger memory capacity

  9. Effects of node buffer and capacity on network traffic

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  10. Impact of Physical Stress on Salivary Buffering Capacity

    Directory of Open Access Journals (Sweden)

    Yu Nakashima

    2016-12-01

    Full Text Available Background: Saliva has many properties and the buffering capacity is important for the neutralization of oral fluids. It is unclear whether stressful conditions directly affect salivary buffering capacity, and we investigated the impact of physical stress on salivary buffering capacity. Methods: Twelve participants were subjected to the physical stress of jogging and running. The salivary buffering capacity and flow rate of the participants were measured before and after exposure to stressful conditions. Salivary α-amylase activity was measured as a quantitative index of stress. Results: No change in buffering capacity was detected among each time point during the whole course under physically stressful conditions. Next, we examined the change in buffering capacity after jogging compared to baseline. Six participants showed an increase in buffering capacity (Group A, while the other six participants showed a decrease or no change (Group B after jogging. Group B showed a decrease in flow rate and increases in α-amylase activity and protein level after jogging, whereas Group A showed no changes in these properties. Conclusions: The results suggest that salivary buffering capacity changes following exposure to physically stressful conditions, and that the changes are dependent on the stress susceptibility of individuals.

  11. Dynamic Buffer Capacity in Acid?Base Systems

    OpenAIRE

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

    2015-01-01

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

  12. Dynamic Buffer Capacity in Acid-Base Systems.

    Science.gov (United States)

    Michałowska-Kaczmarczyk, Anna M; Michałowski, Tadeusz

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

  13. The influence of tooth brushing time over saliva buffering capacity

    OpenAIRE

    Sri Mulyanti; Hetty Anggrawati

    2014-01-01

    Saliva gives a considerable influence against the growth of dental caries as a natural defense against caries. the things very important about saliva are its flow rate and buffering capacity. the decrease in saliva flow rate might cause food retention that furthermore would turn into dental plaques, meanwhile it’s buffering capacity will play a considerable role in maintaining the saliva’s pH and remineralization process of the teeth. One of the mechanisms which are considered to be effective...

  14. Huge capacity optical packet switching and buffering.

    Science.gov (United States)

    Shinada, Satoshi; Furukawa, Hideaki; Wada, Naoya

    2011-12-12

    We demonstrate 2.56 Tbit/s/port dual-polarization DWDM/DQPSK variable-length optical packet (20 Gbit/s × 64 wavelengths × 2 polarizations) switching and buffering by using a 2×2 optical packet switch (OPS) system. The optical data plane of the OPS system was constructed of multi-connected electro-optical switches and fiber delay lines. The accumulated polarization dependent loss of each optical path in the data plane was less than 5 dB. This low-polarization-dependence OPS system enabled us to handle DWDM/DQPSK optical packets (1.28 Tbit/s/port) with time-varying polarization after transmission through 100 km fiber in the field. © 2011 Optical Society of America

  15. Mapping Soil pH Buffering Capacity of Selected Fields

    Science.gov (United States)

    Weaver, A. R.; Kissel, D. E.; Chen, F.; West, L. T.; Adkins, W.; Rickman, D.; Luvall, J. C.

    2003-01-01

    Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One hundred thirty six soil samples (0 to 15 cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b (slope of pH vs. lime added) = 0.00029 - 0.00003 * % clay + 0.00135 * % O/C, r(exp 2) = 0.68. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(exp 2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities.

  16. 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.

  17. Buffer capacity of the coelomic fluid in echinoderms.

    Science.gov (United States)

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

    2013-09-01

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

  18. [Meeting point Stewart. Buffer bases, base excess and strong ions].

    Science.gov (United States)

    Lang, W

    2007-04-01

    Development of a two-buffer model which simulates the acid-base properties of blood and allows comparison of the different acidbase concepts according to Stewart and to Siggaard-Andersen. The two-buffer model consisted of different aqueous solutions of bicarbonate/CO(2) (pCO(2), sCO(2), pK(1)), HEPES buffer (A(tot), pK(a)) and electrolytes. These were used to calculate the pH from the independent variables according to Stewart - strong ion difference (SID), pCO(2) and total concentration of the weak acids (A(tot)) - from which all other dependent variables (cHCO(3)(-), cA(-), BB, BE) were obtained and compared with the measured values. The normal pH (7.408) was calculated from the normal values for SID (48 mmol/l), pCO(2) (40 mmHg) and A(tot) (45.2 mmol/l) and agreed perfectly with the measured value (7.409+/-0.001). This was also valid for all calculated and measured pH values when the SID was varied: non-respiratory alkalosis ( upward arrow) or acidosis ( downward arrow), pCO(2):respiratory acidosis ( upward arrow) or alkalosis ( downward arrow) and A(tot):hyperproteinemic acidosis ( upward arrow) or hypoproteinemic alkalosis ( downward arrow) were varied and the sum of the buffer bases (BB) was always equal to the SID. All changes and hence BE were also equal, providing that A(tot) was normal. This was not the case, however, if A(tot) was outside the normal range, when BE was then the difference from the normal BB at the respective reference point. Whereas the deviation of the measured pCO(2) was acceptable (1.74+/-0.86 mmHg), this was not the case for the SID (-6.18+/-3.58 mmol/l) calculated from the measured ion concentrations (Na, K, Ca, Cl). Despite controversial discussions, both concepts are much closer than might be expected. Whereas in the Stewart approach the focus of analysis is on plasma, with the Siggaard-Andersen approach it is on blood. Hence, a combined analysis of the blood gases (pH, pCO(2), pO(2), sO(2), cHb, BE) and of the strong ion gap (SIG

  19. Buffering capacity and membrane H+ conductance of Halobacterium halobium.

    Science.gov (United States)

    Rius, N; Lorén, J G

    1996-09-01

    Buffering capacity and membrane H+ conductance were measured in Halobacterium halobium suspensions in the light and in the dark over a wide range of external pH. The values of both variables for this archaeobacterium were significantly higher than those found for eubacteria in other reports. It appears from our results that the special chemical composition of the cell envelope and the movement of ions, mainly protons, may influence the magnitude of the buffering power and the H+ membrane conductance of these cells.

  20. RADIATA PINE pH AND BUFFERING CAPACITY: EFFECT OF AGE AND LOCATION IN THE STEM

    OpenAIRE

    Hernandez,Vicente

    2013-01-01

    In this work the effect of age and location within the stem on pH and buffering capacity of radiata pine sapwood was investigated. Mature and juvenile wood samples from three different heights in the trunk were obtained from 20, 25, and 30 year-old trees. Aqueous wood extracts from the samples were used to determine the pH and buffering capacity of wood. Results show a significant effect of age and location in the tree, although a strong interaction among all factors was also detected. In gen...

  1. Assessment on bearing capacity of buffer material to overpack

    International Nuclear Information System (INIS)

    Hirai, Takashi; Tanai, Kenji; Takaji, Kazuhiko; Ohnuma, Satoshi

    2003-02-01

    To objective of this report is to clarify the characteristics of the bearing capacity of the buffer material against the deformation of the overpack in the engineered barrier system. In the second progress report by JNC, it was reported that the well designed engineered barrier system is stable and safety on mechanical support of the overpack to ensure stability and stress which acts on the overpack by some analysis. However, the degree of the capacity to the ultimate state and the background data of the design are not necessary clarified in the report. Therefore it is considered to be important to assess the ultimate state and make the relationship clear between deformation and bearing capacity of the overpack in the engineered barrier system. So the scale test and the simulation analysis were carried out for the longitudinal deformation of the overpack in the saturated buffer material constrained by the host rock. From the result of the scale test and the analysis it appears that the bearing capacity is increasing with the deformation of the overpack even if the bearing capacity is over the yield force and the relationship between deformation and bearing capacity can be approximately expressed by the simple function. (author)

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

    Science.gov (United States)

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

    2015-04-01

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

  3. The influence of tooth brushing time over saliva buffering capacity

    Directory of Open Access Journals (Sweden)

    Sri Mulyanti

    2014-11-01

    Full Text Available Saliva gives a considerable influence against the growth of dental caries as a natural defense against caries. the things very important about saliva are its flow rate and buffering capacity. the decrease in saliva flow rate might cause food retention that furthermore would turn into dental plaques, meanwhile it’s buffering capacity will play a considerable role in maintaining the saliva’s pH and remineralization process of the teeth. One of the mechanisms which are considered to be effective in preventing dental caries is teeth brushing which could change the pH of 5,6 to a normal level. And the right time of teeth brushing will provide an optimal result.The study aims to reveal the influence of teeth brushing time against saliva buffering capacity. The study is an analytic study using a quasi-experimental design. The samples of the study are 20 (twenty students of dentistry in Health Ministry of Bandung which was purposively selected the sample is divided into 3 groups. The first group is treated by brushing their teeth right after eating bread, the second and third group is treated 15 and 30 minutes after eating bread. The hypothesis uses Kruskal Wallis hypothesis continued by Mann Whitney test, strikethrough. The study reveals that the group brushed their teeth right after eating bread shows low category of saliva buffering is that 55% meanwhile those who brushed their teeth 15 and 30 minutes after eating bread exhibits the result as much as 65% and 25 % Thus the last group is included to those who have a medium risk of suffering from dental carries. The statistics of Kruskal Wallis test within the confidence level of 95% shows that there is an influence of teeth brushing time over the saliva buffering capacity with p<0,001. Mann Whitney test shows that the time of teeth brushing within 15 minutes after eating is better than the group who brush their teeth 30 minutes after eating.

  4. 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…

  5. There is no capacity limited buffer in the Murdock (1962) free recall data.

    Science.gov (United States)

    Tarnow, Eugen

    2010-12-01

    Theories of short term memory often include a limited capacity "buffer". Such a buffer contains items which do not decay at all but are overwritten by new data. I show that one of the experiments that fueled the buffer concept, the free recall experiments by Murdock (J Exp Psychol 64(5):482-488, 1962), does not contain such a buffer.

  6. Efficient Computation of Buffer Capacities for Cyclo-Static Dataflow Graphs

    NARCIS (Netherlands)

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

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

  7. Efficient Computation of Buffer Capacities for Cyclo-Static Dataflow Graphs

    NARCIS (Netherlands)

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

    2006-01-01

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

  8. Moisture buffer capacity of cement-lime plasters with enhanced thermal storage capacity

    Science.gov (United States)

    Fořt, Jan; Pavlíková, Milena; Pavlík, Zbyšek

    2017-07-01

    Indoor air temperature and relative humidity represent important parameters for health and working efficiency of buildings occupants. Beside the moderation of temperature, investigation of hygric properties of building materials with connection to indoor relative humidity variation became recognized as a relevant factor for energy efficient building maintenance. The moisture buffer value introduced in the Nordtest protocol can be used for estimation of moisture buffer capacity of building materials or their multi-layered systems. In this paper, both the ideal and real moisture buffer values are examined on the basis of simulation of diurnal relative humidity fluctuations in plasters with incorporated PCM admixture. Retrieved data points to a complex effect of the tested plasters on possible moderation of buildings interior climate.

  9. There is no capacity limited buffer in the Murdock (1962) free recall data

    OpenAIRE

    Tarnow, Eugen

    2010-01-01

    Theories of short term memory often include a limited capacity “buffer”. Such a buffer contains items which do not decay at all but are overwritten by new data. I show that one of the experiments that fueled the buffer concept, the free recall experiments by Murdock (J Exp Psychol 64(5):482–488, 1962), does not contain such a buffer.

  10. ROBUST : The ROle of BUffering capacities in STabilising coastal lagoon ecosystems

    NARCIS (Netherlands)

    de Wit, R; Stal, LJ; Lomstein, BA; Herbert, RA; van Gemerden, H; Viaroli, P; Cecherelli, VU; Rodriguez-Valera, F; Bartoli, M; Giordani, G; Azzoni, R; Schaub, B; Welsh, DT; Donnelly, A; Cifuentes, A; Anton, J; Finster, K; Nielsen, LB; Pedersen, AGU; Neubauer, AT; Colangelo, MA; Heijs, SK

    2001-01-01

    "Buffer capacities" has been defined in ecology as a holistic concept (e.g., Integration of Ecosystem Theories: A Pattern, second ed. Kluwer, Dordrecht, 1997, 388pp), but we show that it can also be worked out in mechanistic studies. Our mechanistic approach highlights that "buffering capacities"

  11. ROBUST: The ROle of BUffering capacities in STabilising coastal lagoon ecosystems

    NARCIS (Netherlands)

    De Wit, R.; Stal, L.J.; Lomstein, B.A.; Herbert, R.A.; van Gemerden, H.; Viaroli, P.; Cecherelli, V.U.; Rodriguez-Valera, F.; Bartoli, M.; Giordani, G.; Azzoni, R.; Schaub, B.; Welsh, D.T.; Donnelly, A.; Cifuentes, A.; Anton, J.; Finster, K.; Nielsen, L.P.; Pedersen, A.G.U.; Neubauer, A.T.; Colangelo, M.A.; Heijs, S.K.

    2001-01-01

    "Buffer capacities" has been defined in ecology as a holistic concept (e.g., Integration of Ecosystem Theories: A Pattern, second ed. Kluwer, Dordrecht, 1997, 388pp), but we show that it can also be worked out in mechanistic studies. Our mechanistic approach highlights that "buffering capacities"

  12. Salivary buffer capacity, pH, and stimulated flow rate of crack cocaine users.

    Science.gov (United States)

    Woyceichoski, Iverson Ernani Cogo; Costa, Carlos Henrique; de Araújo, Cristiano Miranda; Brancher, João Armando; Resende, Luciane Grochocki; Vieira, Iran; de Lima, Antonio Adilson Soares

    2013-08-01

    Crack cocaine is the freebase form of cocaine that can be smoked. The use of this drug has been considered a public health problem in many countries. The aim of this study was to assess the stimulated salivary flow rate (SSFR), pH, and the buffer capacity of saliva in crack cocaine users. Stimulated whole saliva was collected from 54 selected crack cocaine users and 40 non-users. All samples were analyzed for SSFR, pH, and buffer capacity. SSFR was analyzed by gravimetric method. The buffer capacity and pH were determined using a digital pH meter. The crack cocaine users demonstrated higher buffer capacity than the control group (P > 0.05). Salivary pH was lower in crack cocaine users (P 0.05). Crack cocaine users might exhibit a significant decrease in salivary pH, but not in salivary flow rate or buffer capacity. © 2012 Blackwell Publishing Asia Pty Ltd.

  13. Evaluation of in situ sulfate reduction as redox buffer capacity in groundwater flow path

    International Nuclear Information System (INIS)

    Ioka, Seiichiro; Iwatsuki, Teruki; Amano, Yuki; Furue, Ryoji

    2007-01-01

    For safety assessment of geological isolation, it is important to evaluate in situ redox buffer capacity in high-permeability zone as groundwater flow path. The study evaluated in situ sulfate reduction as redox buffer capacity in the conglomerate bedding in Toki Lignite-bearing Formation, which occurs at the lowest part of sedimentary rocks overlying basement granite. The bedding plays an important role as the main groundwater flow path. The result showed that in situ redox buffer capacity in the conglomerate bedding has been identified on first nine months, whereas in the following period the redox buffer capacity has not been identified for about fifteen months. This will be caused by the bedding became inappropriate for microbial survival as the organic matter which is needfuel for microbial activity was consumed. Thus, there will be limited redox buffer capacity in groundwater flow path even in formation including organic matter-bearing layer. (author)

  14. Capacity gains of buffer-aided moving relays

    KAUST Repository

    Zafar, Ammar

    2017-03-14

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

  15. Biogeochemical processes and buffering capacity concurrently affect acidification in a seasonally hypoxic coastal marine basin

    Science.gov (United States)

    Hagens, M.; Slomp, C. P.; Meysman, F. J. R.; Seitaj, D.; Harlay, J.; Borges, A. V.; Middelburg, J. J.

    2015-03-01

    Coastal areas are impacted by multiple natural and anthropogenic processes and experience stronger pH fluctuations than the open ocean. These variations can weaken or intensify the ocean acidification signal induced by increasing atmospheric pCO2. The development of eutrophication-induced hypoxia intensifies coastal acidification, since the CO2 produced during respiration decreases the buffering capacity in any hypoxic bottom water. To assess the combined ecosystem impacts of acidification and hypoxia, we quantified the seasonal variation in pH and oxygen dynamics in the water column of a seasonally stratified coastal basin (Lake Grevelingen, the Netherlands). Monthly water-column chemistry measurements were complemented with estimates of primary production and respiration using O2 light-dark incubations, in addition to sediment-water fluxes of dissolved inorganic carbon (DIC) and total alkalinity (TA). The resulting data set was used to set up a proton budget on a seasonal scale. Temperature-induced seasonal stratification combined with a high community respiration was responsible for the depletion of oxygen in the bottom water in summer. The surface water showed strong seasonal variation in process rates (primary production, CO2 air-sea exchange), but relatively small seasonal pH fluctuations (0.46 units on the total hydrogen ion scale). In contrast, the bottom water showed less seasonality in biogeochemical rates (respiration, sediment-water exchange), but stronger pH fluctuations (0.60 units). This marked difference in pH dynamics could be attributed to a substantial reduction in the acid-base buffering capacity of the hypoxic bottom water in the summer period. Our results highlight the importance of acid-base buffering in the pH dynamics of coastal systems and illustrate the increasing vulnerability of hypoxic, CO2-rich waters to any acidifying process.

  16. Simplified and quantitative saliva buffer capacity test using a hand-held pH meter.

    Science.gov (United States)

    Kitasako, Yuichi; Moritsuka, Michiyo; Foxton, Richard M; Ikeda, Masaomi; Tagami, Junji; Nomura, Satoshi

    2005-06-01

    To evaluate and compare saliva buffer capacity using a hand-held pH meter and a commercial buffer strip in patients at risk of caries. To obtain stimulated saliva, 109 patients were given a paraffin wax to chew for 5 minutes. After reading the pH value of 0.5 ml of tested saliva using a portable hand-held pH meter (B-212), 10 microl of 0.1N HCl was titrated into the obtained saliva up to a total titration of 160 microl, and then the pH value read each time. The commercial buffer strip (CRT) was also evaluated. The correlation in ranking results (high, medium, low) between the B-212 pH meter and CRT buffer were statistically analyzed by the Bartlett's test (P pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). The percentages of the tested patients for the different ranks (high, medium, low) of buffer capacity were 50%, 17% and 33% respectively for the B-212 pH meter, and 56%, 17% and 27% respectively for the CRT. For the CRT buffer, 23 out of 109 cases showed inconclusive color change under the colorimetric test. There was significant correlation between ranking buffer capacity measured by the B-212 pH meter and the CRT buffer (P < 0.001).

  17. Buffering Capacity of pH in Backfill

    International Nuclear Information System (INIS)

    Benbow, Steven; Robinson, Peter; Savage, David

    2002-08-01

    Gravel backfills may help retard the migration of hyperalkaline cement pore fluids in repository designs containing large amounts of cement and concrete (e.g. the proposed Swedish SFL 3-5 repository) by acting as a 'sacrificial' reactive barrier. This behaviour relies on the reaction of silicate and aluminosilicate minerals in the backfill through hydroxyl ion-catalysed mineral dissolution reactions and the associated precipitation of hydroxyl ion bearing solids, such as calcium silicate hydrates. Recent work published by SKB on potential reaction mechanisms and assessment of the potential performance of such backfills has been reviewed, and scoping calculations to assess likely backfill performance have been carried out. The approaches and methodologies employed by SKB to model the potential for buffering of hydroxyl ions released by cementitious engineered barriers by reaction with a surrounding gravel barrier are considered to have a number of deficiencies. In particular, mass balance calculations used a non-conservative estimate of the amount of hydroxyl ions which may be consumed by precipitation of CSH minerals. More conservative choices of the composition of CSH suggest that complete reaction of at least 36 % of the gravel barrier (as currently designed), and possibly much more, would be required to contain the release of all hydroxyl ions contained within cement in SFL 3-5. Also, SKB's scoping calculations overestimate the amount of quartz/SiO 2 likely to be present in the gravel backfill, thus leading to an overestimation of the likely amount of retardation of hydroxyl ion migration through the backfill. Moreover, SKB's calculations assumed that the reactive surface area of particles in the gravel backfill does not change with time and that the rate-limiting step of release of silica remains detachment of silicate ions from the mineral surfaces. However, evidence from SKB's own experiments suggests that the surface area available for dissolution will

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  19. Effect of initial conditions, boundary conditions and thickness on the moisture buffering capacity of spruce plywood

    Energy Technology Data Exchange (ETDEWEB)

    Osanyintola, O. F.; Talukdar, P.; Simonson, C. J. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Sask. (China)

    2006-07-01

    In this paper, the moisture buffering capacity of spruce plywood is measured by recording the change in mass of a test specimen when the air relative humidity (RH) is changed between 33% RH and 75% RH. The aim is to represent diurnal cycles in indoor humidity with 33% RH maintained for 16 h and 75% RH maintained for 8 h. Measurements are taken using two different apparatuses, which provide different convective transfer coefficients between the air and the plywood, and the results are compared to a numerical model for validation. The validated numerical model is then used to investigate the effect of initial conditions, boundary conditions and thickness on the moisture buffering capacity of plywood. The results show that the buffering capacity of plywood depends on the initial conditions and thickness of the plywood as well as the surface film coefficient and humidity cycle. (author)

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

    Science.gov (United States)

    Baicu, Simona C; Taylor, Michael J

    2002-08-01

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

  1. Effects of dietary carbohydrates and buffering capacity on nutrient digestibility and manure characteristics in finishing pigs

    NARCIS (Netherlands)

    Mroz, Z.; Moeser, A.J.; Vreman, K.; Diepen, van J.T.; Kempen, van T.; Canh, T.T.; Jongbloed, A.W.

    2000-01-01

    A 2 × 3 factorial experiment was conducted with 24 finishing pigs (Yorkshire x [Finnish Landrace x Dutch Landrace]) to determine the effects of dietary buffering capacity (BC) and carbohydrate sources on apparent total tract digestibility (TD), N retention, and manure characteristics. Twelve of

  2. Efficient Buffer Capacity and Scheduler Setting Computation for Soft Real-Time Stream Processing Applications

    NARCIS (Netherlands)

    Bekooij, Marco; Bekooij, Marco Jan Gerrit; Wiggers, M.H.; van Meerbergen, Jef; Falk, H.; Marwedel, P.

    2007-01-01

    Soft real-time applications that process data streams can often be intuitively described as dataflow process networks. In this paper we present a novel analysis technique to compute conservative estimates of the required buffer capacities in such process networks. With the same analysis technique

  3. Computation of Buffer Capacities for Throughput Constrained and Data Dependent Inter-Task Communication

    NARCIS (Netherlands)

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

    2008-01-01

    Streaming applications are often implemented as task graphs. Currently, techniques exist to derive buffer capacities that guarantee satisfaction of a throughput constraint for task graphs in which the inter-task communication is data-independent, i.e. the amount of data produced and consumed is

  4. Probabilistic Capacity Assessment of Lattice Transmission Towers under Strong Wind

    Directory of Open Access Journals (Sweden)

    Wei eZhang

    2015-10-01

    Full Text Available Serving as one key component of the most important lifeline infrastructure system, transmission towers are vulnerable to multiple nature hazards including strong wind and could pose severe threats to the power system security with possible blackouts under extreme weather conditions, such as hurricanes, derechoes, or winter storms. For the security and resiliency of the power system, it is important to ensure the structural safety with enough capacity for all possible failure modes, such as structural stability. The study is to develop a probabilistic capacity assessment approach for transmission towers under strong wind loads. Due to the complicated structural details of lattice transmission towers, wind tunnel experiments are carried out to understand the complex interactions of wind and the lattice sections of transmission tower and drag coefficients and the dynamic amplification factor for different panels of the transmission tower are obtained. The wind profile is generated and the wind time histories are simulated as a summation of time-varying mean and fluctuating components. The capacity curve for the transmission towers is obtained from the incremental dynamic analysis (IDA method. To consider the stochastic nature of wind field, probabilistic capacity curves are generated by implementing IDA analysis for different wind yaw angles and different randomly generated wind speed time histories. After building the limit state functions based on the maximum allowable drift to height ratio, the probabilities of failure are obtained based on the meteorological data at a given site. As the transmission tower serves as the key nodes for the power network, the probabilistic capacity curves can be incorporated into the performance based design of the power transmission network.

  5. Optimal capacity and buffer size estimation under Generalized Markov Fluids Models and QoS parameters

    International Nuclear Information System (INIS)

    Bavio, José; Marrón, Beatriz

    2014-01-01

    Quality of service (QoS) for internet traffic management requires good traffic models and good estimation of sharing network resource. A link of a network processes all traffic and it is designed with certain capacity C and buffer size B. A Generalized Markov Fluid model (GMFM), introduced by Marrón (2011), is assumed for the sources because describes in a versatile way the traffic, allows estimation based on traffic traces, and also consistent effective bandwidth estimation can be done. QoS, interpreted as buffer overflow probability, can be estimated for GMFM through the effective bandwidth estimation and solving the optimization problem presented in Courcoubetis (2002), the so call inf-sup formulas. In this work we implement a code to solve the inf-sup problem and other optimization related with it, that allow us to do traffic engineering in links of data networks to calculate both, minimum capacity required when QoS and buffer size are given or minimum buffer size required when QoS and capacity are given

  6. Strong Generative Capacity and the Empirical Base of Linguistic Theory

    Directory of Open Access Journals (Sweden)

    Dennis Ott

    2017-09-01

    Full Text Available This Perspective traces the evolution of certain central notions in the theory of Generative Grammar (GG. The founding documents of the field suggested a relation between the grammar, construed as recursively enumerating an infinite set of sentences, and the idealized native speaker that was essentially equivalent to the relation between a formal language (a set of well-formed formulas and an automaton that recognizes strings as belonging to the language or not. But this early view was later abandoned, when the focus of the field shifted to the grammar's strong generative capacity as recursive generation of hierarchically structured objects as opposed to strings. The grammar is now no longer seen as specifying a set of well-formed expressions and in fact necessarily constructs expressions of any degree of intuitive “acceptability.” The field of GG, however, has not sufficiently acknowledged the significance of this shift in perspective, as evidenced by the fact that (informal and experimentally-controlled observations about string acceptability continue to be treated as bona fide data and generalizations for the theory of GG. The focus on strong generative capacity, it is argued, requires a new discussion of what constitutes valid empirical evidence for GG beyond observations pertaining to weak generation.

  7. Capacity buffer of the saliva in children and adolescents with cancer: Variations induced by the administration of metotrexate or cyclophosphamide.

    Science.gov (United States)

    Rojas-Morales, Thais; Lugo, Zulecnys; Santana, Yrma; Navas, Rita; Zambrano, Olga; Viera, Ninoska; García, Isaura

    2005-07-01

    To determine the variations in the levels of capacity buffer of the saliva in children and adolescents with cancer that receiving Metotrexate or cyclophosphamide. A clinical, random-controlled assay was carried out. The sample was composed by 24 children, ages between 2 and 16 years, with diagnostic of Leukemia and Lymphomas attending to The Autonomous Service of University Hospital of Maracaibo and Hospital of Pediatric Specialties. Two groups were conformed to which a sample of saliva was taken before and after the chemotherapy; twelve patients were randomly placed in the G1: patient receiving Metotrexate and twelve in the G2: patient receiving cyclophosphamide. In order to determine the capacity buffer, the CRT Buffer IVOCLAR VIVADENT was used. The capacity salivary buffer did not show significant differences before and after the administration of the cytostatic agents studied. In this study, the Metotrexate or cyclophosphamide administration does not modify the salivary buffer capacity in pediatric patient with cancer.

  8. Strong intermediate-depth Vreancea earthquakes: Damage capacity in Bulgaria

    International Nuclear Information System (INIS)

    Kouteva-Guentcheva, M.P.; Paskaleva, I.P.; Panza, G.F.

    2008-08-01

    The sustainable development of the society depends not only on a reasonable policy for economical growth but also on the reasonable management of natural risks. The regional earthquake danger due to the Vrancea intermediate-depth earthquakes dominates the hazard of NE Bulgaria. These quakes have particularly long-period and far-reaching effects, causing damages at large epicentral distances. Vrancea events energy attenuates considerably less rapidly than that of the wave field radiated by the seismically active zones in Bulgaria. The available strong motion records at Russe, NE Bulgaria, due to both Vrancea events - August 30, 1986 and May 30, 1990 show higher seismic response spectra amplitudes for periods up to 0.6 s for the horizontal components, compared to the values given in the Bulgarian Code and Eurocode 8. A neo-deterministic analytical procedure which models the wavefield generated by a realistic earthquake source, as it propagates through a laterally varying anelastic medium, is applied to obtain the seismic loading at Russe. After proper validation, using the few available data and parametric analyses, from the synthesized seismic signals damage capacity of selected scenario Vrancea quakes is estimated and compared with available capacity curves for some reinforced concrete and masonry structures, representative of the Balkan Region. The performed modelling has shown that the earthquake focal mechanisms control the seismic loading much more than the local geology, and that the site response should be analyzed by considering the whole thickness of sediments until the bedrock, and not only the topmost 30 m. (author)

  9. Avaliação da capacidade tamponante - um experimento participativo Buffer capacity evaluating - a collaborative experiment

    Directory of Open Access Journals (Sweden)

    César Ricardo Silva

    2000-06-01

    Full Text Available The aim of this work is to show an experiment from which students can learn some of the main characteristics of buffer solutions. A mixture of some acid-base indicators, named as Yamada's indicator, can be used to estimate pH values in an acid-base titration of a buffer, with good approximation. In the experiment it is also possible to verify the relationship between the buffer capacity and the concentrations and the molar ratio of the components of a NH3 / NH4+ buffer solution. The shortage of experiments associated with the relative small importance given to many aspects of buffer solutions, is now explored with simplicity. In the proposed experiments, students prepare buffer solutions by themselves, calculate the pH, understand how acid-base indicators act and learn how buffer solutions work through graph constructed by sharing experimental data.

  10. PNW cetacean muscle biochemistry - Muscle Myoglobin Content and Acid Buffering Capacity of Cetaceans from the Pacific Northwest to Assess Dive Capacity and the Development of Diving Capabilities

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project assesses the development of two important skeletal muscle adaptations for diving (enhanced myoglobin content and acid buffering capacities) in a range...

  11. Comparison and trend study on acidity and acidic buffering capacity of particulate matter in China

    Science.gov (United States)

    Ren, Lihong; Wang, Wei; Wang, Qingyue; Yang, XiaoYang; Tang, Dagang

    2011-12-01

    The acidity of about 2000 particulate matter samples from aircraft and ground-based monitoring is analyzed by the method similar to soil acidity determination. The ground-based samples were collected at about 50 urban or background sites in northern and southern China. Moreover, the acidic buffering capacity of those samples is also analyzed by the method of micro acid-base titration. Results indicate that the acidity level is lower in most northern areas than those in the south, and the acidic buffering capacity showed inverse tendency, correspondingly. This is the most important reason why the pollution of acidic-precipitation is much more serious in Southern China than that in Northern China. The acidity increases and the acidic buffering capacity drops with the decreasing of the particle sizes, indicating that fine particle is the main influencing factor of the acidification. The ionic results show that Ca salt is the main alkaline substance in particulate matter, whereas the acidification of particulate matter is due to the SO 2 and NO x emitted from the fossil fuel burning. And among of them, coal burning is the main contributor of SO 2, however the contribution of NO x that emitted from fuel burning of motor vehicles has increased in recent years. By comparison of the experimental results during the past 20 years, it can be concluded that the acid precipitation of particulate matter has not been well controlled, and it even shows an increasing tendency in China lately. The acid precipitation of particulate matter has begun to frequently attack in part of the northern areas. Multiple regression analysis indicates that coefficient value of the ions is the lowest at the urban sites and the highest at the regional sites, whereas the aircraft measurement results are intermediate between those two kinds of sites.

  12. Effects of the buffering capacity of the soil on the mobilization of heavy metals. Equilibrium and kinetics.

    Science.gov (United States)

    Villen-Guzman, Maria; Paz-Garcia, Juan M; Amaya-Santos, Gema; Rodriguez-Maroto, Jose M; Vereda-Alonso, Carlos; Gomez-Lahoz, Cesar

    2015-07-01

    Understanding the possible pH-buffering processes is of maximum importance for risk assessment and remediation feasibility studies of heavy-metal contaminated soils. This paper presents the results about the effect of the buffering capacity of a polluted soil, rich in carbonates, on the pH and on the leaching evolution of its main contaminant (lead) when a weak acid (acetic acid) or a strong one (nitric acid) are slowly added. In both cases, the behavior of lead dissolution could be predicted using available (scientifically verified freeware) models assuming equilibrium between the solid and the aqueous phase. However, the experimental results indicate that the dissolution of calcium and magnesium carbonates is kinetically controlled. These kinetic limitations affect the overall behavior, and should be considered to understand also the response of the metals under local equilibrium. The well-known BCR sequential extraction procedure was used before- and after-treatment, to fractionate the lead concentration in the soil according to its mobility. The BCR results were also in agreement with the predictions of the equilibrium model. This agreement allows new insights about the information that could be derived from the BCR fractionation analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Phylogeny strongly drives seed dormancy and quality in a climatically buffered hotspot for plant endemism.

    Science.gov (United States)

    Dayrell, Roberta L C; Garcia, Queila S; Negreiros, Daniel; Baskin, Carol C; Baskin, Jerry M; Silveira, Fernando A O

    2017-01-01

    Models of costs and benefits of dormancy (D) predict that the evolutionarily stable strategy in long-term stable environments is for non-dormancy (ND), but this prediction remains to be tested empirically. We reviewed seed traits of species in the climatically buffered, geologically stable and nutrient-impoverished campo rupestre grasslands in Brazil to test the hypothesis that ND is favoured over D. We examined the relative importance of life-history traits and phylogeny in driving the evolution of D and assessed seed viability at the community level. Germination and viability data were retrieved from 67 publications and ND/D was determined for 168 species in 25 angiosperm families. We also obtained the percentage of embryoless, viable and dormant seeds for 74 species. Frequencies of species with dormant and non-dormant seeds were compared with global databases of dormancy distribution. The majority of campo rupestre taxa (62·5 %) had non-dormant seeds, and the ND/D ratio was the highest for any vegetation type on Earth. Dormancy was unrelated to other species life-history traits, suggesting that contemporary factors are poor predictors of D. We found a significant phylogenetic structure in the dormancy categorical trait. Dormancy diversity was highly skewed towards the root of the phylogenetic tree and there was a strong phylogenetic signal in the data, suggesting a major role of phylogeny in determining the evolution of D versus ND and seed viability. Quantitative analysis of the data revealed that at least half of the seeds produced by 46 % of the surveyed populations were embryoless and/or otherwise non-viable. Our results support the view that long-term climatic and geological stability favour ND. Seed viability data show that campo rupestre species have a markedly low investment in regeneration from seeds, highlighting the need for specific in situ and ex situ conservation strategies to avoid loss of biodiversity. © The Author 2016. Published by Oxford

  14. Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe

    DEFF Research Database (Denmark)

    Lenoir, Jonathan; Graae, Bente; Aarrestad, Per

    2013-01-01

    Recent studies from mountainous areas of small spatial extent (<2500 km(2) ) suggest that fine-grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate-ch...

  15. Stability and buffering capacity of the geosphere for long-term isolation of radioactive waste

    International Nuclear Information System (INIS)

    2004-01-01

    Most experts worldwide agree that radioactive waste disposal in engineered facilities, or repositories, located in appropriate formations deep underground, provide a suitable waste management option for protecting humans and the environment now and. in the future. An NEA workshop was organised on 9-11 December 2003 in Braunschweig, Germany, devoted specifically to argillaceous settings for deep geological repositories. The workshop brought together scientists from academic institutions, engineers from various research institutions or companies, consultants, regulatory authorities and national waste management organisations to establish the scientific basis for stability and buffering capacity of deep geological waste management systems. The present report synthesizes the main outcomes of that workshop and presents a compilation of the related abstracts. (author)

  16. The influence of the nature of background anions on the buffer capacity of glycine-containing electrolytes for nickel electroplating

    Science.gov (United States)

    Dolgikh, O. V.; Zuen, Vu Tkhi; Sotskaya, N. V.

    2009-06-01

    The buffer properties of acetate, sulfate, and chloride glycine-containing electrolytes for nickel electroplating were studied. Various forms of the amino acid and background anions were shown to act in solution as two buffer systems related by competitive complex formation. The buffer capacity of a solution was then the result of the joint action of these systems. The contribution of each of them was determined by its absolute concentration in solution on the one hand and changes in this concentration caused by the addition of H+ or OH- ions on the other.

  17. [Relationship between blood glucose levels and salivary pH and buffering capacity in type II diabetes patients].

    Science.gov (United States)

    Elkafri, I H; Mashlah, A; Shaqifa, A

    2014-03-13

    This study was evaluated the relationship between blood glucose levels and salivary pH and buffering capacity in type II diabetic patients. The sample comprised 210 participants (age ranged 40-60 years). Based on fasting blood glucose levels the participants were divided into 3 groups: controls with normal blood glucose levels; diabetic patients with levels ≤ 200 mg/dL; and diabetic patients with levels > 200 mg/dL. Salivary pH and buffering capacity were determined in a sample of resting (non-stimulated) saliva taken from each participant. Salivary pH levels in diabetic patients with blood glucose levels > 200 mg/dL were lower than in the controls and diabetic patients with levels ≤ 200 mg/dL. Salivary pH levels were comparable in controls and diabetic patients with blood glucose levels ≤ 200 mg/dL. Salivary buffering capacity in the 3 groups was comparable.

  18. Determining the Contribution of Non-Carbonate Alkalinity from Intertidal Salt Marshes to Coastal Buffering Capacity

    Science.gov (United States)

    Anderson, L. B.; Gonneea, M. E.; Wang, A. Z.; Chu, S. N.

    2016-02-01

    Coastal ocean acidification varies with high magnitude and frequency due to both natural and anthropogenic factors, and levels of acidity in coastal waters have important consequences for environmental concerns such as local settlement of bivalve populations. Therefore, it is useful to fully evaluate measurements that increase understanding of coastal ocean acidification dynamics. This study focuses on the quantification and characterization of alkalinity, the ability of a specific water parcel to buffer against inputs of acidity. There has been limited research on the magnitude and composition of non-carbonate alkalinity (NCA) generated in coastal environments. Specifically, this study evaluates the contribution of NCA to total alkalinity (TA) in an intertidal salt marsh, assesses NCA dynamics within the marsh, and begins to determine composition of NCA. We demonstrated that it was possible to develop a CO2-free full titration system modeled after Cai et al. (1998) that produced reasonable values for TA and NCA. From initial use of this system, it was evident that NCA was a significant contributor to TA within the Sage Lot Pond salt marsh, and that NCA was dominated by organic/unknown alkalinity. Preliminary observations indicated that NCA variability in the marsh was directly proportional to water flux entering the tidal creek from Sage Lot Pond. The source of higher NCA concentrations in Sage Lot Pond was unknown, but may have been due to organic/unknown alkalinity generated in a different part of the marsh and exported to our specific tidal creek site. Preliminary assessment of NCA composition indicates an acid/base species with a pK value of 6.46. From evaluation of NCA magnitude and relation to water flux, it is reasonable to conclude that NCA generated within salt marshes may be a significant source of buffering capacity to the coastal ocean.

  19. Buffer capacity of food components influences the acid tolerance response in Salmonella Typhimurium during simulated gastric passage

    DEFF Research Database (Denmark)

    Henriksen, Sidsel; Buschhardt, Tasja; Hansen, Tina Beck

    2014-01-01

    phase Salmonella Typhimurium during simulated gastric acid passage. We used a computer-controlled fermentor to employ pH changes in synthetic gastric fluid, mimicking the dynamic pH during gastric passage. In order to minimise variation, Salmonella enterica serovar Typhimurium was contained in dialysis......Food composition, buffer capacity, and fat and protein content have been shown to effect the gastric acid survival of pathogens (Waterman & Small 1998). In this study, simple food-model substances with different buffer capacities were investigated for their ability to support survival of stationary...... major stationary phase ATR regulators, we found an approx. four-fold increase in expression of ompR and an approx. three-fold increase of rpoS in saline and buffered saline, respectively, after 15 min of gastric acid challenge. The relative expression of these genes, were significantly lower in Brain...

  20. Redox reactions and weak buffering capacity lead to acidification in the Chesapeake Bay.

    Science.gov (United States)

    Cai, Wei-Jun; Huang, Wei-Jen; Luther, George W; Pierrot, Denis; Li, Ming; Testa, Jeremy; Xue, Ming; Joesoef, Andrew; Mann, Roger; Brodeur, Jean; Xu, Yuan-Yuan; Chen, Baoshan; Hussain, Najid; Waldbusser, George G; Cornwell, Jeffrey; Kemp, W Michael

    2017-08-28

    The combined effects of anthropogenic and biological CO 2 inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H 2 S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. We show that a pH minimum occurs in mid-depths where acids are generated as a result of H 2 S oxidation in waters mixed upward from the anoxic depths. Our analyses also suggest a large synergistic effect from river-ocean mixing, global and local atmospheric CO 2 uptake, and CO 2 and acid production from respiration and other redox reactions. Together they lead to a poor acid buffering capacity, severe acidification and increased carbonate mineral dissolution in the USA's largest estuary.The potential contribution of redox reactions to acidification in coastal waters is unclear. Here, using measurements from the Chesapeake Bay, the authors show that pH minimum occurs at mid-depths where acids are produced via hydrogen sulfide oxidation in waters mixed upward from anoxic depths.

  1. Nitrate and Dissolved Organic Carbon In Stream Water: Assessing The Buffer Capacities of Hedgerow Systems. Study Case In Brittany, France

    Science.gov (United States)

    Viaud, V.; Mérot, P.

    Management of landscape structures, such as wetlands or hedgerow systems, could contribute to the control of the non-point source pollution of surface and groundwater. The hydrological and biochemical buffer capacities of hedgerows have been mostly investigated at a local scale, around the hedge. We propose now to consider the effect of hedgerow systems on water and nutrient movements at a larger scale, the small agricultural catchment one, in a perspective of landscape management. A recent work has showed a strong local effect of hedges on subsurface water and nutrient fluxes in autumn, at the beginning of the rainy period. According to those results, three nearby catchments, differing by their hedgerow density, were monitored during the autumn and winter 2001. The study sites are located in Brittany, western France. Daily data allow to compare the dynamics of NO3 , DOC, Cl- and SO4 at the outlet of the - 2- three catchments. The results will be presented and their relationship with the spatial organization of the hedgerow systems will be discussed.

  2. Determination of buffering capacity of selected fermented feedstuffs and the effect of dietary acid-base status on ruminal fluid pH

    Directory of Open Access Journals (Sweden)

    Lukáš Bujňák

    2011-01-01

    Full Text Available The aim of this study was to evaluate the buffering capacity of some fermented feedstuffs and the effect of dietary acid-base status on ruminal fluid pH. The first experiment was performed with different types (n = 24 of wet and dry fermented feedstuffs to determine the buffering capacity and buffer value index. The buffer value index of wet corn silages was more negative than for dry corn silages account on acid loss during drying. In the second experiment, the effects of different concentrations of lactic acid on base-buffering capacity, buffer value index and indicators of fermentation process were studied in two groups of corn silages (n = 21. Two groups of analyzed values were compared using unpaired t-test. Differences among the groups in base-buffering capacity (P P P > 0.05 correlation was found between ruminal pH and dietary buffer value index. These results confirmed that dietary acid-base status alone is not adequate as a predictor of the need for buffers in the diet of lactating cows. It is the first report about using of buffering capacity determination methods for evaluation of feedstuffs and dietary acid-base status in dairy cows.

  3. Titration and Spectroscopic Measurements of Poultry Litter pH Buffering Capacity.

    Science.gov (United States)

    Cassity-Duffey, Kate; Cabrera, Miguel; Mowrer, Jake; Kissel, David

    2015-07-01

    The pH value of poultry litter is affected by nitrification, mineralization, and the addition of acidifying chemicals, all acting on the poultry litter pH buffering capacity (pHBC). Increased understanding of poultry litter pHBC will aid in modeling NH volatilization from surface-applied poultry litter as well as estimating rates of alum applications. Our objectives were to (i) determine the pHBC of a wide range of poultry litters; (ii) assess the accuracy of near-infrared reflectance spectroscopy (NIRS) for determining poultry litter pHBC; and (iii) demonstrate the use of poultry litter pHBC to increase the accuracy of alum additions. Litter pHBC was determined by titration and calculated from linear and sigmoidal curves. For the 37 litters measured, linear pHBC ranged from 187 to 537 mmol (pH unit) kg dry litter. The linear and sigmoidal curves provided accurate predictions of pHBC, with most > 0.90. Results from NIRS analysis showed that the linear pHBC expressed on an "as is" water content basis had a NIRS coefficient of calibration (developed using a modified partial least squares procedure) of 0.90 for the 37 poultry litters measured. Using the litter pHBC, an empirical model was derived to determine the amount of alum needed to create a target pH. The model performed well in the range of pH 6.5 to 7.5 (RMSE = 0.07) but underpredicted the amount of alum needed to reach pH litter, which prevented its hydrolysis. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

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

    Science.gov (United States)

    Kempa, Wojciech M.

    2017-12-01

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

  5. The acid-base buffer capacity of podzolic soils and its changes under the impact of treatment with the Mehra-Jackson and Tamm reagents

    Science.gov (United States)

    Maksimova, Yu. G.; Maryakhina, N. N.; Tolpeshta, I. I.; Sokolova, T. A.

    2010-10-01

    The acid-base buffer capacity before and after the treatment with the Mehra-Jackson and Tamm reagents was assessed by continuous potentiometric titration for the main genetic horizons of two profiles of podzolic soils in the Central Forest State Reserve. The total buffer capacity was calculated in the pH range from the initial titration point (ITP) to 3 for the acid titration and from the ITP to 10 for the base titration, as well as the buffer capacities in the pH intervals of 0.25. It was found that both treatments abruptly decreased the base buffer capacity, which reached 70-90% in the E horizons. The high direct linear correlation of the difference between the total base buffer capacities before and after each treatment with the content of Fe in the Tamm extract was revealed. From the results obtained, a conclusion was drawn that finely dispersed Fe hydroxides were the main solid-phase constituents ensuring the base buffer capacity, and the deprotonation of hydroxyl groups on the surface of Fe hydroxides was the essential buffer reaction during the base titration.

  6. The Approximate Capacity Region of the Symmetric $K$-user Gaussian Interference Channel with Strong Interference

    KAUST Repository

    Chaaban, Anas

    2016-03-01

    The symmetric K-user interference channel is studied with the goal of characterizing its capacity region in the strong interference regime within a constant gap. The achievable rate region of a scheme combining rate-splitting at the transmitters and interference alignment and successive decoding/computation at the receivers is derived. Next it is shown that this scheme achieves the so-called greedy-max corner points of the capacity region within a constant gap. By combining this result with previous results by Ordentlich et al. on the sum-capacity of the symmetric interference channel, a constant gap characterization of the capacity region for the strong interference regime is obtained. This leads to the first approximate characterization of the capacity region of the symmetric K-user IC. Furthermore, a new scheme that achieves the sum-capacity of the channel in the strong interference regime within a constant gap is also proposed, and the corresponding gap is calculated. The advantage of the new scheme is that it leads to a characterization within a constant gap without leaving an outage set contrary to the scheme by Ordentlich et al..

  7. The influence of different recultivation methods on the water buffer capacity in a degraded urban lake

    Directory of Open Access Journals (Sweden)

    Grochowska J.K.

    2013-09-01

    Full Text Available The object of study was Długie Lake, which is located in northeastern Poland. This lake was restored by two methods: artificial aeration and phosphorus inactivation. The aim of this study was to determine the effect of the two methods of rehabilitation on the water buffer properties of the lake. Both of the restoration methods had an impact on the lake’s buffer properties. Artificial aeration reduced the production processes in the reservoir and caused the destruction of the vertical stratification of alkalinity, total hardness and calcium concentration. The phosphorus inactivation method caused a significant decrease in the concentration of phosphorus in the lake water and the further limitation of the production processes. Similar to the state before the lake aeration, a vertical stratification of alkalinity, total hardness and calcium was observed, with increasing values towards the bottom. However, the differences in the values of these parameters between surface water and bottom water were significantly lower than those recorded prior to the remediation. The observed changes after restoration of Długie Lake are very positive in that they are optimal for construction of plant cell walls, shells and fish bones.

  8. The strong anti-glioblastoma capacity of the plasma-stimulated lysine-rich medium

    International Nuclear Information System (INIS)

    Yan, Dayun; Keidar, Michael; Nourmohammadi, Niki; Talbot, Annie; Sherman, Jonathan H

    2016-01-01

    Plasma-stimulated medium (PSM) shows a remarkable anti-cancer capacity as strong as the direct cold atmospheric plasma (CAP) treatment of cancer cells. PSM is able to effectively resist the growth of several cancer cell lines. To date, the sole approach to strengthen the anti-cancer capacity of PSM is extending the plasma treatment time. In this study, we demonstrated that the anti-glioblastoma capacity of PSM could be significantly increased by adding 20 mM lysine in Dulbecco’s modified Eagle’s medium (DMEM). This study provides clear evidence that the anti-glioblastoma capacity of PSM could be noticeably enhanced by modifying the composition of medium without increasing the CAP treatment time. (paper)

  9. Spatial models reveal the microclimatic buffering capacity of old-growth forests

    Science.gov (United States)

    Sarah J. K. Frey; Adam S. Hadley; Sherri L. Johnson; Mark Schulze; Julia A. Jones; Matthew. G. Betts

    2016-01-01

    Climate change is predicted to cause widespread declines in biodiversity, but these predictions are derived from coarse-resolution climate models applied at global scales. Such models lack the capacity to incorporate microclimate variability, which is critical to biodiversity microrefugia. In forested montane regions, microclimate is thought to be influenced by...

  10. Bacteriorhodopsin as a high-resolution, high-capacity buffer for digital holographic measurements

    Science.gov (United States)

    Barnhart, D. H.; Koek, W. D.; Juchem, T.; Hampp, N.; Coupland, J. M.; Halliwell, N. A.

    2004-04-01

    Recent trends in optical metrology suggest that, in order for holographic measurement to become a widespread tool, it must be based on methods that do not require physical development of the hologram. While digital holography has been successfully demonstrated in recent years, unfortunately the limited information capacity of present electronic sensors, such as CCD arrays, is still many orders of magnitude away from directly competing with the high-resolution silver halide plates used in traditional holography. As a result, present digital holographic methods with current electronic sensors cannot record object sizes larger than several hundred microns at high resolution. In this paper, the authors report on the use of bacteriorhodopsin (BR) for digital holography to overcome these limitations. In particular, BR is a real-time recording medium with an information capacity (5000 line-pairs/mm) that even exceeds high resolution photographic film. As such, a centimetre-square area of BR film has the same information capacity of several hundred state-of-the-art CCD cameras. For digital holography, BR temporarily holds the hologram record so that its information content can be digitized for numeric reconstruction. In addition, this paper examines the use of BR for optical reconstruction without chemical development. When correctly managed, it is found that BR is highly effective, in terms of both quality and process time, for three-dimensional holographic measurements. Consequently, several key holographic applications, based on BR, are proposed in this paper.

  11. Laser imprint reduction for the critical-density foam buffered target driven by a relatively strong foot pulse at early stage of laser implosions

    Energy Technology Data Exchange (ETDEWEB)

    Li, J. W., E-mail: li-jiwei@iapcm.ac.cn; He, X. T. [Key Lab of High Energy Density Physics Simulation, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Institute of Applied Physics and Computational Mathematics, P. O. Box 8009, Beijing 100094 (China); Kang, W. [Key Lab of High Energy Density Physics Simulation, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Li, J. H.; Zheng, W. D. [Institute of Applied Physics and Computational Mathematics, P. O. Box 8009, Beijing 100094 (China)

    2015-12-15

    In order to reduce the effect of laser imprint in direct-drive ignition scheme a low-density foam buffered target has been proposed. This target is driven by a laser pulse with a low-intensity foot at the early stage of implosion, which heats the foam and elongates the thermal conduction zone between the laser absorption region and ablation front, increasing the thermal smoothing effect. In this paper, a relatively strong foot pulse is adopted to irradiate the critical-density foam buffered target. The stronger foot, near 1 × 10{sup 14 }W/cm{sup 2}, is able to drive a radiative shock in the low-density foam, which helps smooth the shock and further reduce the effect of laser imprint. The radiative shock also forms a double ablation front structure between the two ablation fronts to further stabilize the hydrodynamics, achieving the similar results to a target with a high-Z dopant in the ablator. 2D analysis shows that for the critical-density foam buffered target irradiated by the strong foot pulse, the laser imprint can be reduced due to the radiative shock in the foam and an increased thermal smoothing effect. It seems viable for the critical-density foam buffered target to be driven by a relatively strong foot pulse with the goal of reducing the laser imprint and achieving better implosion symmetry in the direct-drive laser fusion.

  12. Laser imprint reduction for the critical-density foam buffered target driven by a relatively strong foot pulse at early stage of laser implosions

    International Nuclear Information System (INIS)

    Li, J. W.; He, X. T.; Kang, W.; Li, J. H.; Zheng, W. D.

    2015-01-01

    In order to reduce the effect of laser imprint in direct-drive ignition scheme a low-density foam buffered target has been proposed. This target is driven by a laser pulse with a low-intensity foot at the early stage of implosion, which heats the foam and elongates the thermal conduction zone between the laser absorption region and ablation front, increasing the thermal smoothing effect. In this paper, a relatively strong foot pulse is adopted to irradiate the critical-density foam buffered target. The stronger foot, near 1 × 10 14  W/cm 2 , is able to drive a radiative shock in the low-density foam, which helps smooth the shock and further reduce the effect of laser imprint. The radiative shock also forms a double ablation front structure between the two ablation fronts to further stabilize the hydrodynamics, achieving the similar results to a target with a high-Z dopant in the ablator. 2D analysis shows that for the critical-density foam buffered target irradiated by the strong foot pulse, the laser imprint can be reduced due to the radiative shock in the foam and an increased thermal smoothing effect. It seems viable for the critical-density foam buffered target to be driven by a relatively strong foot pulse with the goal of reducing the laser imprint and achieving better implosion symmetry in the direct-drive laser fusion

  13. Effects of trait anxiety and situational stress on attentional shifting are buffered by working memory capacity.

    Science.gov (United States)

    Edwards, Mark S; Moore, Philippa; Champion, James C; Edwards, Elizabeth J

    2015-01-01

    Attentional Control Theory (ACT) predicts that trait anxiety and situation stress combine to reduce performance efficiency on tasks requiring rapid shifts in attention. Recent evidence has also suggested that working memory capacity (WMC) might moderate this relationship. We controlled for methodological difficulties in the existing literature to investigate the relationships between trait anxiety, situational stress, and WMC on attentional shifting. Seventy undergraduate students participated in the study. Trait anxiety was operationalized using questionnaire scores, situational stress was manipulated through a pressured counting task, and WMC was based on performance on the Automated Operation Span Task (AOSPAN). The shifting task involved a modified version of the Sternberg paradigm as the primary task and an oddball tone-discrimination task as the secondary task. Dependent variables were performance effectiveness (accuracy) and processing efficiency (accuracy divided by response time) on the secondary task. There was no effect of anxiety, stress, or WMC in predicting performance effectiveness; however, a significant three-way interaction on processing efficiency was observed. At higher WMC, anxiety and situational stress were not associated with processing efficiency. Conversely, at lower WMC, higher trait anxiety was associated with poorer efficiency but only for those who reported higher situational stress; for those who reported lower situational stress higher trait anxiety predicted facilitated efficiency. Results are interpreted with respect to ACT and directions for future research are discussed.

  14. Vault-Scale Modelling of pH Buffering Capacity in Crushed Granite Backfills

    International Nuclear Information System (INIS)

    Benbow, Steven; Savage, David; Robinson, Peter; Watson, Sarah

    2004-04-01

    consist of grains of quartz of uniform size of either 4 or 32 mm diameter. The cement pore fluid diffusing from the waste package was assumed to be pure water saturated with portlandite [Ca(OH) 2 ] at 25 deg C. The pore fluid saturating the backfill was assumed to be pure water equilibrated with quartz at 25 deg C. A number of different simulations were carried out for both 4 and 32 mm diameter gravel backfill grains: 1. A 2D horizontal slice through the vault length with a transmissive feature in the host rock parallel to the vault length, but positioned roughly two vault widths from the vault. 2. As (1) above, but considering a 2D vertical slice through the vault. 3. A 2D horizontal slice through the vault width with a transmissive feature in the host rock normal to the vault length. 4. A 2D horizontal slice through the vault length with a transmissive feature in the host rock intersecting the vault at 45 deg to the vault. An additional simulation was also carried out for the geometry considered in model variant (4) above where reaction of quartz was excluded so that only the reaction of Ca(OH) 2 -saturated fluid with ambient groundwater was simulated. The results of the model variants incorporating reaction of quartz were broadly similar, with few differences apparent for the different orientations of the transmissive feature in the host rock. Most simulations showed that the gravel backfill was capable of maintaining pH 4 moles after 10,000 years in a representative 1 m thick slice through the backfill) were dissolved in the gravel adjacent to the waste package to achieve pH buffering. All of the dissolved quartz was converted to CSH solids (tobermorite and gyrolite). Reactions in simulations with the 4 mm diameter backfill grains were slightly faster, but the results were otherwise identical to those for the 32 mm diameter grains. The model variant with no chemical reaction of the backfill particles was considerably different from the other simulations with pH > 11

  15. Correlation of Dental Caries Experience with pH, Buffering Capacity and Flow Rate of Saliva among 15-year-old School Children in Mangalore

    Directory of Open Access Journals (Sweden)

    Vijay S Kumar

    2013-01-01

    Full Text Available Aim and Objectives: To correlate dental caries experience with pH, buffering capacity and flow rate of saliva among 15-year-old-children Materials & Method : Fifteen year old school children from adopted schools of a dental college in Mangalore were considered as study subjects. The study was carried out using a standardized proforma that consisted of questionnaire for recording demographic data. The caries experience was assessed by DMFT Index. Salivary pH was measured by using a pH meter and salivary buffering capacity was measured by using titration method. Unstimulated whole saliva was collected from all subjects by direct expectoration to calculate the flow rate. Results: The mean DMFT of the study population was 2.85 ± 2.5. The mean salivary pH was found to be 6.88 ± 0.69.About 74.1% were having medium salivary buffering capacities. The mean unstimulated salivary flow rate and mean total antioxidant capacity of the study population was 0.41 ± 0.14 ml/min and 94.15 ± 60.72 g/dL respectively. Conclusions: A marked association between the pH, buffering capacity and unstimulated flow rate with dental caries experience suggest that assessment of these salivary parameters can be used as predictors for future dental caries susceptibility in an individual.

  16. Low Buffer Capacity and Alternating Motility along the Human Gastrointestinal Tract: Implications for in Vivo Dissolution and Absorption of Ionizable Drugs.

    Science.gov (United States)

    Hens, Bart; Tsume, Yasuhiro; Bermejo, Marival; Paixao, Paulo; Koenigsknecht, Mark J; Baker, Jason R; Hasler, William L; Lionberger, Robert; Fan, Jianghong; Dickens, Joseph; Shedden, Kerby; Wen, Bo; Wysocki, Jeffrey; Loebenberg, Raimar; Lee, Allen; Frances, Ann; Amidon, Greg; Yu, Alex; Benninghoff, Gail; Salehi, Niloufar; Talattof, Arjang; Sun, Duxin; Amidon, Gordon L

    2017-12-04

    In this study, we determined the pH and buffer capacity of human gastrointestinal (GI) fluids (aspirated from the stomach, duodenum, proximal jejunum, and mid/distal jejunum) as a function of time, from 37 healthy subjects after oral administration of an 800 mg immediate-release tablet of ibuprofen (reference listed drug; RLD) under typical prescribed bioequivalence (BE) study protocol conditions in both fasted and fed states (simulated by ingestion of a liquid meal). Simultaneously, motility was continuously monitored using water-perfused manometry. The time to appearance of phase III contractions (i.e., housekeeper wave) was monitored following administration of the ibuprofen tablet. Our results clearly demonstrated the dynamic change in pH as a function of time and, most significantly, the extremely low buffer capacity along the GI tract. The buffer capacity on average was 2.26 μmol/mL/ΔpH in fasted state (range: 0.26 and 6.32 μmol/mL/ΔpH) and 2.66 μmol/mL/ΔpH in fed state (range: 0.78 and 5.98 μmol/mL/ΔpH) throughout the entire upper GI tract (stomach, duodenum, and proximal and mid/distal jejunum). The implication of this very low buffer capacity of the human GI tract is profound for the oral delivery of both acidic and basic active pharmaceutical ingredients (APIs). An in vivo predictive dissolution method would require not only a bicarbonate buffer but also, more significantly, a low buffer capacity of dissolution media to reflect in vivo dissolution conditions.

  17. Sea level rise, surface warming, and the weakened buffering ability of South China Sea to strong typhoons in recent decades.

    Science.gov (United States)

    Sun, Jingru; Oey, Leo; Xu, F-H; Lin, Y-C

    2017-08-07

    Each year, a number of typhoons in the western North Pacific pass through the Luzon Strait into South China Sea (SCS). Although the storms remain above a warm open sea, the majority of them weaken due to atmospheric and oceanic environments unfavorable for typhoon intensification in SCS, which therefore serves as a natural buffer that shields the surrounding coasts from potentially more powerful storms. This study examines how this buffer has changed over inter-decadal and longer time scales. We show that the buffer weakens (i.e. greater potential for more powerful typhoons) in negative Pacific Decadal Oscillation (PDO) years, as well as with sea-level-rise and surface warming, caused primarily by the deepening of the ocean's 26 °C isotherm Z 26 . A new Intensity Change Index is proposed to describe the typhoon intensity change as a function of Z 26 and other environmental variables. In SCS, the new index accounts for as high as 75% of the total variance of typhoon intensity change.

  18. Evaluation of pH, buffering capacity, viscosity and flow rate levels of saliva in caries-free, minimal caries and nursing caries children: An in vivo study.

    Science.gov (United States)

    Animireddy, Dwitha; Reddy Bekkem, Venkata Thimma; Vallala, Pranitha; Kotha, Sunil Babu; Ankireddy, Swetha; Mohammad, Noorjahan

    2014-07-01

    The present study was undertaken to evaluate the pH, buffering capacity, viscosity and flow rate of saliva in caries free, minimal caries and nursing caries children and to evaluate the relationship of these on the caries activity of children. A total of 75 school children of age group between 4 and 12 years were selected and divided into three equal groups: Group I, Group II and Group III, consisting of 25 subjects each. Group I included caries-free subjects, Group II included subjects with minimal caries and Group III included subjects with nursing caries. Saliva samples were collected from all subjects and were estimated for flow rate, pH, buffering capacity and viscosity. There was a significant decrease in the mean salivary flow rate, salivary ph and salivary buffer capacity and a significant increase in the salivary viscosity among caries-free subjects, subjects with minimal caries and subjects with nursing caries. The physicochemical properties of saliva, such as salivary flow rate, pH, buffering capacity and viscosity, has a relation with caries activity in children and act as markers of caries activity.

  19. The pH-static enzyme sensor : An ISFET-based enzyme sensor, insensitive to the buffer capacity of the sample

    NARCIS (Netherlands)

    van der Schoot, Bart H.; Bergveld, Piet

    1987-01-01

    An ISFET-based urea sensor is combined with a noble-metal electrode which provides continuous coulometric titration of the products of the enzymatic reaction. The sensor thus becomes independent of the buffer capacity of the sample; and because the enzyme is operating at a constant pH, the linear

  20. The Evaluation of Saliva Flow Rate, pH, Buffer Capacity, Microbiological Content and Indice of Decayed, Missing and Filled Teeth in Behçet's Patients.

    Science.gov (United States)

    Erdem, Vildan; Yıldız, Mehmet; Erdem, Teoman

    2013-06-01

    Several lines of evidence indicate that oral microbial flora play a critical role in the pathogenesis of Behçet disease. Saliva flow rate, buffer capacity and microorganism content are very important in the maintenance of oral health. We aimed to evaluate saliva flow rate, pH, buffer capacity and Streptococcus mutans and Lactobacilli content along with the decayed, missing, and filled tooth index in Behçet's patients. Case-control study. Forty patients with active Behçet disease [female:male (F/M) 21/19, mean age 31.05±11.08 years] and forty healthy persons (F/M 21/19, mean age 31.03±9.14 years) were included in the study. The oral region was first examined, and the decayed, missing, and filled tooth index was calculated for each person. Stimulated saliva was collected and divided into two separate millimetric tubes to calculate the buffer capacity of the saliva, determine Streptococcus mutans and Lactobacilli levels and measure the pH of the saliva. A Caries Risk Test buffer strip was used to calculate the buffer capacity. Caries Risk Test bacterial kit was used to determine Streptococcus mutans and lactobacilli levels. A pH meter was used to measure the pH of the saliva. The mean saliva pH of the patients was higher than the controls (7.76±0.51, 7.18±0.46, respectively) (p0.05). We think that the maintenance of oral health by effective, regular tooth brushing, regular dental check-ups and dental treatment for Behçet patients is very important for the prevention and therapy of Behçet disease.

  1. The Evaluation of Saliva Flow Rate, pH, Buffer Capacity, Microbiological Content and Indice of Decayed, Missing and Filled Teeth in Behçet"s Patients

    Directory of Open Access Journals (Sweden)

    Vildan Erdem

    2013-06-01

    Full Text Available Background: Several lines of evidence indicate that oral microbial flora play a critical role in the pathogenesis of Behçet disease. Saliva flow rate, buffer capacity and microorganism content are very important in the maintenance of oral health. Aims: We aimed to evaluate saliva flow rate, pH, buffer capacity and Streptococcus mutans and Lactobacilli content along with the decayed, missing, and filled tooth index in Behçet’s patients. Study Design: Case-control study Methods: Forty patients with active Behçet disease [female:male (F/M 21/19, mean age 31.05±11.08 years] and forty healthy persons (F/M 21/19, mean age 31.03±9.14 years were included in the study. The oral region was first examined, and the decayed, missing, and filled tooth index was calculated for each person. Stimulated saliva was collected and divided into two separate millimetric tubes to calculate the buffer capacity of the saliva, determine Streptococcus mutans and Lactobacilli levels and measure the pH of the saliva. A Caries Risk Test buffer strip was used to calculate the buffer capacity. Caries Risk Test bacterial kit was used to determine Streptococcus mutans and lactobacilli levels. A pH meter was used to measure the pH of the saliva. Results: The mean saliva pH of the patients was higher than the controls (7.76±0.51, 7.18±0.46, respectively (p0.05. Conclusion: We think that the maintenance of oral health by effective, regular tooth brushing, regular dental check-ups and dental treatment for Behçet patients is very important for the prevention and therapy of Behçet disease.

  2. Divergent responses of soil buffering capacity to long-term N deposition in three typical tropical forests with different land-use history.

    Science.gov (United States)

    Lu, Xiankai; Mao, Qinggong; Mo, Jiangming; Gilliam, Frank S; Zhou, Guoyi; Luo, Yiqi; Zhang, Wei; Huang, Juan

    2015-04-07

    Elevated anthropogenic nitrogen (N) deposition has become an important driver of soil acidification at both regional and global scales. It remains unclear, however, how long-term N deposition affects soil buffering capacity in tropical forest ecosystems and in ecosystems of contrasting land-use history. Here, we expand on a long-term N deposition experiment in three tropical forests that vary in land-use history (primary, secondary, and planted forests) in Southern China, with N addition as NH4NO3 of 0, 50, 100, and 150 kg N ha(-1) yr(-1), respectively. Results showed that all three forests were acid-sensitive ecosystems with poor soil buffering capacity, while the primary forest had higher base saturation and cation exchange capacity than others. However, long-term N addition significantly accelerated soil acidification and decreased soil buffering capacity in the primary forest, but not in the degraded secondary and planted forests. We suggest that ecosystem N status, influenced by different land-use history, is primarily responsible for these divergent responses. N-rich primary forests may be more sensitive to external N inputs than others with low N status, and should be given more attention under global changes in the future, because lack of nutrient cations is irreversible.

  3. The effect of pH, buffer capacity and ionic strength on quetiapine fumarate release from matrix tablets prepared using two different polymeric blends.

    Science.gov (United States)

    Hamed, Rania; AlJanabi, Reem; Sunoqrot, Suhair; Abbas, Aiman

    2017-08-01

    The objective of this study was to investigate the effect of the different physiological parameters of the gastrointestinal (GI) fluid (pH, buffer capacity, and ionic strength) on the in vitro release of the weakly basic BCS class II drug quetiapine fumarate (QF) from two once-a-day matrix tablet formulations (F1 and F2) developed as potential generic equivalents to Seroquel ® XR. F1 tablets were prepared using blends of high and low viscosity grades of hydroxypropyl methylcellulose (HPMC K4M and K100LV, respectively), while F2 tablets were prepared from HPMC K4M and PEGylated glyceryl behenate (Compritol ® HD5 ATO). The two formulations attained release profiles of QF over 24 h similar to that of Seroquel ® XR using the dissolution medium published by the Food and Drug Administration (FDA). A series of solubility and in vitro dissolution studies was then carried out using media that simulate the gastric and intestinal fluids and cover the physiological pH, buffer capacity and ionic strength range of the GIT. Solubility studies revealed that QF exhibits a typical weak base pH-dependent solubility profile and that the solubility of QF increases with increasing the buffer capacity and ionic strength of the media. The release profiles of QF from F1, F2 and Seroquel ® XR tablets were found to be influenced by the pH, buffer capacity and ionic strength of the dissolution media to varying degrees. Results highlight the importance of studying the physiological variables along the GIT in designing controlled release formulations for more predictive in vitro-in vivo correlations.

  4. Contribution of solution pH and buffer capacity to suppress intergranular stress corrosion cracking of sensitized type 304 stainless steel at 95 C

    International Nuclear Information System (INIS)

    Zhang, S.; Shibata, T.; Haruna, T.

    1999-01-01

    Controlling pH of high-temperature water to ∼pH 7 at 300 C by adding lithium hydroxide (LiOH) into the coolant system of a pressurized water reactor (PWR) successfully has been mitigating the corrosion of PWR component materials. The effects of solution pH and buffer capacity on intergranular stress corrosion cracking (IGSCC) of sensitized type 304 stainless steel ([SS] UNS S30400) was examined at 95 C by slow strain rate technique (SSRT) with an in-situ cracking observation system. It was found that an increase in solution pH or buffer capacity increased crack initiation time and decreased mean crack initiation frequency, but exerted almost no effect on crack propagation. This inhibition effect on IGSCC initiation was explained as resulting from a retarding effect of solution pH and buffer capacity on the decrease in pH at crack nuclei caused by the hydrolysis of metal ions dissolved when the passive film was ruptured by strain in SSRT

  5. Synaptic vesicle pool size, release probability and synaptic depression are sensitive to Ca2+ buffering capacity in the developing rat calyx of Held

    Directory of Open Access Journals (Sweden)

    R.M. Leão

    2009-01-01

    Full Text Available The calyx of Held, a specialized synaptic terminal in the medial nucleus of the trapezoid body, undergoes a series of changes during postnatal development that prepares this synapse for reliable high frequency firing. These changes reduce short-term synaptic depression during tetanic stimulation and thereby prevent action potential failures during a stimulus train. We measured presynaptic membrane capacitance changes in calyces from young postnatal day 5-7 (p5-7 or older (p10-12 rat pups to examine the effect of calcium buffer capacity on vesicle pool size and the efficiency of exocytosis. Vesicle pool size was sensitive to the choice and concentration of exogenous Ca2+ buffer, and this sensitivity was much stronger in younger animals. Pool size and exocytosis efficiency in p5-7 calyces were depressed by 0.2 mM EGTA to a greater extent than with 0.05 mM BAPTA, even though BAPTA is a 100-fold faster Ca2+ buffer. However, this was not the case for p10-12 calyces. With 5 mM EGTA, exocytosis efficiency was reduced to a much larger extent in young calyces compared to older calyces. Depression of exocytosis using pairs of 10-ms depolarizations was reduced by 0.2 mM EGTA compared to 0.05 mM BAPTA to a similar extent in both age groups. These results indicate a developmentally regulated heterogeneity in the sensitivity of different vesicle pools to Ca2+ buffer capacity. We propose that, during development, a population of vesicles that are tightly coupled to Ca2+ channels expands at the expense of vesicles more distant from Ca2+ channels.

  6. Association of polymorphisms in the carbonic anhydrase 6 gene with salivary buffer capacity, dental plaque pH, and caries index in children aged 7-9 years.

    Science.gov (United States)

    Peres, R C R; Camargo, G; Mofatto, L S; Cortellazzi, K L; Santos, M C L G; Nobre-dos-Santos, M; Santos, M N; Bergamaschi, C C; Line, S R P

    2010-04-01

    Carbonic anhydrase VI is a secreted enzyme that catalyzes the hydration of carbon hydroxide in saliva and other body fluids. This enzyme has been implicated in taste and gastrointestinal dysfunctions, tooth erosion, and caries. The purpose of this study was to analyze the allele and genotype distribution of three polymorphisms in the coding sequences of (CA6) gene and check for possible associations with salivary buffer capacity, number of decayed, missing, and filled teeth in deciduous and permanent teeth (dmft/DMFT, Decayed/Missing/Filled Teeth), plaque index (PI), and the plaque pH variation (DeltapH) in children aged 7-9 years. Two hundred and forty-five children from both genders, residents in area with fluoridated water (Piracicaba, São Paulo, Brazil) were divided into two groups: caries free and with caries. The clinical examinations were conducted by a single previously calibrated examiner (kappa=0.91) in an outdoor setting using a mirror and a probe, according to WHO criteria index (dmft/DMFT). Approximately 2 h after the first daily meal, the buffer capacity (BC) and the plaque pH were analyzed by means of a pH meter and an ion selective electrode. Plaque pH was measured immediately and 5 min after a mouth rinse with a 10% sucrose solution. The data were submitted to chi(2), Student's, and Mann-Whitney tests (alpha=0.05). The PI and DeltapH of the upper and lower teeth were significantly higher in the carious group than control (P0.05). There was a positive association between buffer capacity and the rs2274327 (C/T) polymorphism. The allele T and genotype TT were significantly less frequent in individuals with the highest buffer capacity (P=0.023 and 0.045, respectively). This finding encourages future studies relating CA6 gene polymorphisms and their association with malfunctions, such as taste and gastrointestinal alterations, or the differential effect of chemical modulators on the protein products originated from the distinct genotypes of the CA6

  7. Building Teachers' Data-Use Capacity: Insights from Strong and Developing Coaches

    Science.gov (United States)

    Huguet, Alice; Marsh, Julie A.; Farrell, Caitlin C.

    2014-01-01

    Coaching has become a central strategy in district and school efforts to build teacher capacity to interpret and respond to student learning data. Despite their popularity, there is limited research on the implementation of these initiatives. This article begins to addresses this gap by examining the elements of a coach's practice that appear…

  8. Salivary protein concentration, flow rate, buffer capacity and pH estimation: A comparative study among young and elderly subjects, both normal and with gingivitis and periodontitis

    Directory of Open Access Journals (Sweden)

    Mulki Shaila

    2013-01-01

    Full Text Available Background: To evaluate the salivary protein concentration in gingivitis and periodontitis patients and compare the parameters like salivary total protein, salivary albumin, salivary flow rate, pH, buffer capacity and flow rate in both young and elderly patients with simple methods. Materials and Methods: One hundred and twenty subjects were grouped based on their age as young and elderly. Each group was subgrouped (20 subjects as controls, gingivitis and periodontitis. Unstimulated whole saliva was collected from patients and flow rate was noted down during collection of the sample. Salivary protein estimation was done using the Biuret method and salivary albumin was assessed using the Bromocresol green method. pH was estimated with a pHmeter and buffering capacity was analyzed with the titration method. Student′s t-test, Fisher′s test (ANOVA and Tukey HSD (ANOVA tests were used for statistical analysis. Results: A very highly significant rise in the salivary total protein and albumin concentration was noted in gingivitis and periodontitis subjects of both young and elderly. An overall decrease in salivary flow rate was observed among the elderly, and also the salivary flow rate of women was significantly lower than that of men. Conclusion: S ignificant associations between salivary total protein and albumin in gingivitis and periodontitis were found with simple biochemical tests. A decrease in salivary flow rate among elderly and among women was noted.

  9. Determination of Henry's constant, the dissociation constant, and the buffer capacity of the bicarbonate system in ruminal fluid.

    Science.gov (United States)

    Hille, Katharina T; Hetz, Stefan K; Rosendahl, Julia; Braun, Hannah-Sophie; Pieper, Robert; Stumpff, Friederike

    2016-01-01

    Despite the clinical importance of ruminal acidosis, ruminal buffering continues to be poorly understood. In particular, the constants for the dissociation of H2CO3 and the solubility of CO2 (Henry's constant) have never been stringently determined for ruminal fluid. The pH was measured in parallel directly in the rumen and the reticulum in vivo, and in samples obtained via aspiration from 10 fistulated cows on hay- or concentrate-based diets. The equilibrium constants of the bicarbonate system were measured at 38°C both using the Astrup technique and a newly developed method with titration at 2 levels of partial pressure of CO2 (pCO2; 4.75 and 94.98 kPa), yielding mean values of 0.234 ± 0.005 mmol ∙ L(-1) ∙ kPa(-1) and 6.11 ± 0.02 for Henry's constant and the dissociation constant, respectively (n/n = 31/10). Both reticular pH and the pH of samples measured after removal were more alkalic than those measured in vivo in the rumen (by ΔpH = 0.87 ± 0.04 and 0.26 ± 0.04). The amount of acid or base required to shift the pH of ruminal samples to 6.4 or 5.8 (base excess) differed between the 2 feeding groups. Experimental results are compared with the mathematical predictions of an open 2-buffer Henderson-Hasselbalch equilibrium model. Because pCO2 has pronounced effects on ruminal pH and can decrease rapidly in samples removed from the rumen, introduction of a generally accepted protocol for determining the acid-base status of ruminal fluid with standard levels of pCO2 and measurement of base excess in addition to pH should be considered. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  10. Organellar Calcium Buffers

    Science.gov (United States)

    Prins, Daniel; Michalak, Marek

    2011-01-01

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

  11. pKa value and buffering capacity of acidic monomers commonly used in self-etching primers.

    Science.gov (United States)

    Salz, Ulrich; Mücke, Angela; Zimmermann, Jörg; Tay, Franklin R; Pashley, David H

    2006-06-01

    The aim of this investigation was to characterize acidic monomers used in self-etching primers/adhesives by determination of their pKa values and by calculation of their calcium dissolving capacity in comparison with phosphoric and hydrochloric acid. The following acidic monomers were included in this study: 4-methacryloyloxyethyl trimellitate anhydride (4-META), 10-methacryloyloxydecyl dihydrogen phosphate (MDP), dimethacryloyloxyethyl hydrogen phosphate (di-HEMA-phosphate), ethyl 2-[4-(dihydroxyphosphoryl)-2-oxabutyl]acrylate (EAEPA), 2-[4-(dihydroxyphosphoryl)-2-ox-abutyl]acrylic acid (HAEPA), and 2,4,6 trimethylphenyl 2-[4-(dihydroxyphosphoryl)-2-oxabutyl]acrylate (MAEPA). The pKa values were obtained by titration with 0.1 mol/l NaOH in aqueous solution. The inflection points of the resulting potentiometric titration curve were determined as pKa values. In the case of the sparingly water-soluble acidic monomers MAEPA and 4-META, the co-solvent method using different water/ethanol ratios for MAEPA or water/acetone ratios for 4-META was used. The dissolving capacity of each acidic monomer is defined as the amount of hydroxyapatite (HA) dissolved by 1 g of acid. For each monomer, the HA dissolving capacity was calculated bythe corresponding pKa value and the molecular weight. To confirm the calculated dissolving capacities, increasing amounts of HA powder (100 mg portions) were slowly added to 15 mmol/l aqueous solutions of the monomers to determine how much HA could be dissolved in the acidic solutions. For all the investigated acidic monomers, pKal values between 1.7 to 2.5 were observed. The pKa2 values for the phosphate/phosphonate derivatives are between 7.0 and 7.3, and are comparable to phosphoric acid. For dicarboxylic acid derivatives, the pKa2 values are in the range of 4.2 to 4.5. Due to their comparable molecular weights and pKal values, the three tested acids di-HEMA phosphate, MDP and 4-META all possess comparable dissolving capacities for HA (ie, 0

  12. Why the developing nations like India need strong capacity building efforts in greenhouse gases mitigation?

    Science.gov (United States)

    Vishal, V.; Sudhakaran, A.; Singh, T. N.

    2014-12-01

    Today, India rubs shoulders with nations like USA and China for being the major shareholders in global greenhouse emissions and has more emissions than Russia! Carbon Capture, Utilization and Storage (CCUS) has been proven as a reliable method to counter global warming and keep the 2ºC per year policy in check and is currently in the pilot stage in many developed nations. The three major requirements for CCUS are: manpower in diverse fields, implementation potential and capital. Keeping other social problems aside, India still has sufficient mankind in all spheres of research ranging from earth science, engineering, basic sciences, economy, policy making, regulation, public outreach etc. to successfully work on such challenges. India has leading academic institutions, research labs and universities in science and engineering. They also have a working power force in aspects like economy, policy making, regulation, public outreach etc. in various management institutes of repute. India, however, lacks in sufficient funding for advanced research and capacity building schemes to support projects of such scale. Deployment of facts and concepts on climate change need an approach of much greater scope than what is anticipated. The above workforces can put forth a clear picture about the various entities surrounding CCUS and provide sensible planning and implementation information through scientific research. CCUS is only possible when the direct anthropogenic emitters like fossil fuel plants modify their features to incorporate the methods associated with it. The rural population has to be educated in context to the safety of the storage sites. Above all, the Indian government must holistically divert funds for such programs and provide economic incentives to the industries for the industries. The bottom line is that India has been working in lots of aspects with not very clear cuts objectives. There are CO2 capture technologies like amine scrubbing and membrane

  13. Strong Correlation Between Isoprene Emission and Gross Photosynthetic Capacity During Leaf Phenology of the Tropical Tree Species Hymenaea courbaril

    Science.gov (United States)

    Kuhn, U.; Rottenberger, S.; Biesenthal, T.; Wolf, A.; Schebeske, G.; Ciccioli, P.; Kesselmeier, J.

    2004-12-01

    Composition and amount of volatile organic compound (VOC) emission of the tropical tree species Hymenaea courbaril was studied under different developmental stages at a remote Amazonian rainforest site. The different stages covered young leaves (= grown full in size, but not fully turgescent) in the end of the dry season, mature leaves in the end of dry and wet season, and senescent leaves in the end of dry season. Though the diel isoprene emissions pattern could adequately be modelled by a current isoprene algorithm, the basal emission capacity of isoprene changed considerably over the course of leaf development. The inadequacy of using one single standard emission factor to represent the VOC emission capacity of tropical vegetation for an entire seasonal cycle is obvious. A strong linear correlation between the isoprene emission capacity and the gross photosynthetic capacity (GPmax) covering all developmental stages and seasons was observed. Hence, basic leaf photosynthetic activity may offer a valuable basis to model the seasonal variation of isoprene emission, especially in tropical regions where the environmental conditions vary less than in temperate regions. Of special interest was the light dependent monoterpene emission found exclusively in the period between bud break and leave maturity. The finding of this temporary emergence of monoterpene emission may be of general interest in understanding both the ecological functions of isoprenoid production and the regulatory processes involved.

  14. Thermodynamics of nucleotide binding to actomyosin V and VI: a positive heat capacity change accompanies strong ADP binding.

    Science.gov (United States)

    Robblee, James P; Cao, Wenxiang; Henn, Arnon; Hannemann, Diane E; De La Cruz, Enrique M

    2005-08-02

    We have measured the energetics of ATP and ADP binding to single-headed actomyosin V and VI from the temperature dependence of the rate and equilibrium binding constants. Nucleotide binding to actomyosin V and VI can be modeled as two-step binding mechanisms involving the formation of collision complexes followed by isomerization to states with high nucleotide affinity. Formation of the actomyosin VI-ATP collision complex is much weaker and slower than for actomyosin V. A three-step binding mechanism where actomyosin VI isomerizes between two conformations, one competent to bind ATP and one not, followed by rapid ATP binding best accounts for the data. ADP binds to actomyosin V more tightly than actomyosin VI. At 25 degrees C, the strong ADP-binding equilibria are comparable for actomyosin V and VI, and the different overall ADP affinities arise from differences in the ADP collision complex affinity. The actomyosin-ADP isomerization leading to strong ADP binding is entropy driven at >15 degrees C and occurs with a large, positive change in heat capacity (DeltaC(P) degrees ) for both actomyosin V and VI. Sucrose slows ADP binding and dissociation from actomyosin V and VI but not the overall equilibrium constants for strong ADP binding, indicating that solvent viscosity dampens ADP-dependent kinetic transitions, presumably a tail swing that occurs with ADP binding and release. We favor a mechanism where strong ADP binding increases the dynamics and flexibility of the actomyosin complex. The heat capacity (DeltaC(P) degrees ) and entropy (DeltaS degrees ) changes are greater for actomyosin VI than actomyosin V, suggesting different extents of ADP-induced structural rearrangement.

  15. Measurements on cation exchange capacity of bentonite in the long-term test of buffer material (LOT)

    International Nuclear Information System (INIS)

    Muurinen, A.

    2011-01-01

    Determination of cation exchange capacity (CEC) of bentonite in the LOT experiment was the topic of this study. The measurements were performed using the complex of copper(II) ion with trietylenetetramine [Cu(trien)] 2+ as the index cation. Testing of the determination method suggested that (i) drying and wetting of the bentonite, and (ii) exchange time affect the obtained result. The real CEC measurements were carried out with the bentonite samples taken from the A2 parcel of the LOT experiment. The CEC values of the LOT samples were compared with those of the reference samples taken from the same bentonite batch before the compaction of the blocks for the experiment. The conclusions drawn have been made on the basis of the results determined with the wet bentonite samples using the direct exchange of two weeks with 0.01 M [Cu(trien)] 2+ solution because this method gave the most complete cation exchange in the CEC measurements. The differences between the samples taken from different places of the A2 parcel were quite small and close to the accuracy of the method. However, it seems that the CEC values of the field experiment are somewhat higher than the CEC of the reference samples and the values of the hot area are higher than those obtained from the low temperature area. It is also obvious that the variation of CEC increases with increasing temperature. (orig.)

  16. Influence of training intensity on adaptations in acid/base transport proteins, muscle buffer capacity, and repeated-sprint ability in active men.

    Science.gov (United States)

    McGinley, Cian; Bishop, David J

    2016-12-01

    McGinley C, Bishop DJ. Influence of training intensity on adaptations in acid/base transport proteins, muscle buffer capacity, and repeated-sprint ability in active men. J Appl Physiol 121: 1290-1305, 2016. First published October 14, 2016; doi:10.1152/japplphysiol.00630.2016-This study measured the adaptive response to exercise training for each of the acid-base transport protein families, including providing isoform-specific evidence for the monocarboxylate transporter (MCT)1/4 chaperone protein basigin and for the electrogenic sodium-bicarbonate cotransporter (NBCe)1. We investigated whether 4 wk of work-matched, high-intensity interval training (HIIT), performed either just above the lactate threshold (HIITΔ20; n = 8), or close to peak aerobic power (HIITΔ90; n = 8), influenced adaptations in acid-base transport protein abundance, nonbicarbonate muscle buffer capacity (βm in vitro ), and exercise capacity in active men. Training intensity did not discriminate between adaptations for most proteins measured, with abundance of MCT1, sodium/hydrogen exchanger (NHE) 1, NBCe1, carbonic anhydrase (CA) II, and CAXIV increasing after 4 wk, whereas there was little change in CAIII and CAIV abundance. βm in vitro also did not change. However, MCT4 protein content only increased for HIITΔ20 [effect size (ES): 1.06, 90% confidence limits × / ÷ 0.77], whereas basigin protein content only increased for HIITΔ90 (ES: 1.49, × / ÷ 1.42). Repeated-sprint ability (5 × 6-s sprints; 24 s passive rest) improved similarly for both groups. Power at the lactate threshold only improved for HIITΔ20 (ES: 0.49; 90% confidence limits ± 0.38), whereas peak O 2 uptake did not change for either group. Detraining was characterized by the loss of adaptations for all of the proteins measured and for repeated-sprint ability 6 wk after removing the stimulus of HIIT. In conclusion, 4 wk of HIIT induced improvements in each of the acid-base transport protein families, but, remarkably, a 40

  17. Método para avaliação clínica da capacidade tamponante salivar A method for the clinical evaluation of salivary buffer capacity

    Directory of Open Access Journals (Sweden)

    Augusto César Cropanese SPADARO

    1998-07-01

    Full Text Available O presente estudo teve por objetivo o desenvolvimento e a padronização de um método colorimétrico para avaliar a capacidade tamponante salivar média de nossa população. As amostras de saliva estimulada foram tituladas sem eliminação do CO2. Estudos foram realizados para verificar a influência da perda de CO2 das amostras durante o período necessário para a realização das titulações e para a padronização do tempo de leitura do pH. A partir das titulações realizadas nas amostras de saliva de 206 indivíduos de ambos os sexos na faixa etária de 5 a 50 anos, na proporção de 0,77:1:0,44, respectivamente para crianças, jovens e adultos, foram feitas as distribuições de freqüências dos casos, a determinação média do pH inicial, do pKa, microequivalentes relativos ao final da titulação, pH final da titulação e uma estimativa da porcentagem da saliva titulada em pH 5. Com base nestas variáveis foi estabelecida uma classificação dos indivíduos quanto à capacidade tamponante. Análise dos resultados utilizando-se 11, 12 ou 13 microequivalentes de H+/ml indicam que o valor de 11 microequivalentes/ml de saliva é o mais apropriado para a avaliação da capacidade tamponante salivar em nossa população.The present study aimed to develop and standardize a colorimetric method for assessing salivary buffer capacity adapted to the features of the Brazilian population. Samples of stimulated saliva were titrated without CO2 elimination. The assessment was carried out to study the influence of the loss of CO2 from the samples during the few minutes necessary for titration, and to standardize the instants for measuring pH. Saliva samples were titrated from 206 individuals from both genders, between 5 and 50 years of age, and in a proportion of 0.77 : 1 : 0.44, respectively of children, youngsters, and adults. Case frequency distribution; determination of average values of initial pH, pKa, µ equivalents related to titration

  18. Comparative evaluation of the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP and xylitol-containing chewing gum on salivary flow rate, pH and buffering capacity in children: An in vivo study

    Directory of Open Access Journals (Sweden)

    Rahul J Hegde

    2017-01-01

    Full Text Available Aim: This study aimed to compare and evaluate the changes in the salivary flow rate, pH, and buffering capacity before and after chewing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP and xylitol-containing chewing gums in children. Materials and Methods: Sixty children aged between 8 and 12 years were selected for the study. They were randomly divided into Group 1 (CPP-ACP chewing gum and Group 2 (xylitol-containing chewing gum comprising thirty children each. Unstimulated and stimulated saliva samples at 15 and 30 min interval were collected from all children. All the saliva samples were estimated for salivary flow rate, pH, and buffering capacity. Results: Significant increase in salivary flow rate, pH, and buffering capacity from baseline to immediately after spitting the chewing gum was found in both the study groups. No significant difference was found between the two study groups with respect to salivary flow rate and pH. Intergroup comparison indicated a significant increase in salivary buffer capacity in Group 1 when compared to Group 2. Conclusion: Chewing gums containing CPP-ACP and xylitol can significantly increase the physiochemical properties of saliva. These physiochemical properties of saliva have a definite relation with caries activity in children.

  19. Investigating on the fermentation behavior of six lactic acid bacteria strains in barley malt wort reveals limitation in key amino acids and buffer capacity.

    Science.gov (United States)

    Nsogning, Sorelle Dongmo; Fischer, Susann; Becker, Thomas

    2018-08-01

    Understanding lactic acid bacteria (LAB) fermentation behavior in malt wort is a milestone towards flavor improvement of lactic acid fermented malt beverages. Therefore, this study aims to outline deficiencies that may exist in malt wort fermentation. First, based on six LAB strains, cell viability and vitality were evaluated. Second, sugars, organic acids, amino acids, pH value and buffering capacity (BC) were monitored. Finally, the implication of key amino acids, fructose and wort BC on LAB growth was determined. Short growth phase coupled with prompt cell death and a decrease in metabolic activity was observed. Low wort BC caused rapid pH drop with lactic acid accumulation, which conversely increased the BC leading to less pH change at late-stage fermentation. Lactic acid content (≤3.9 g/L) was higher than the reported inhibitory concentration (1.8 g/L). Furthermore, sugars were still available but fructose and key amino acids lysine, arginine and glutamic acid were considerably exhausted (≤98%). Wort supplementations improved cell growth and viability leading to conclude that key amino acid depletion coupled with low BC limits LAB growth in malt wort. Then, a further increase in organic acid reduces LAB viability. This knowledge opens doors for LAB fermentation process optimization in malt wort. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Evaluation of different approaches to quantify strong organic acidity and acid-base buffering of organic-rich surface waters in Sweden.

    Science.gov (United States)

    Köhler, Stephan; Hruska, Jakub; Jönsson, Jörgen; Lövgren, Lars; Lofts, Stephen

    2002-11-01

    The role of organic acids in buffering pH in surface waters has been studied using a small brownwater stream (26mg L(-1) TOC) draining a forested catchment in Northern Sweden. Under the conditions of elevated pressure of CO2 stream field pH was changed between 3.5 and 6.1 during the acidification and alkalinization experiment. Acid-base characteristics of the natural organic matter were also determined using a high precision potentiometric method for a concentrated sample from the same stream. We compared the predictions from the Windermere Humic Aqueous Model (WHAM Model V), a model derived from the potentiometric titration (diprotic/monoprotic acid model) and a previously derived triprotic acid model which only uses alkalinity and TOC as input variables. The predicted buffering characteristics of all three models are very similar in the pH range 4.5-7 which suggests that during routine analysis alkalinity and TOC are sufficient to give a good estimate of organic acid anion charge contribution in a large range of surface waters. A slightly adjusted version of WHAM V successfully describes the organic charge contribution in a large number of sampled surface water lakes, which were previously used to calibrate the triprotic model.

  1. Redox buffer capacity of sedimentary rocks around uranium deposit. Study of water-mineral-microbe system at the Tono uranium deposit, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Iwatsuki, Teruki; Murakami, Yuki; Hama, Katsuhiro [Japan Nuclear Cycle Development Inst., Toki, Gifu (Japan). Tono Geoscience Center; Naganuma, Takeshi [Hiroshima Univ., Higashi-Hiroshima, Hiroshima (Japan). School of Biosphere Sciences

    2003-06-01

    The redox buffer capacity of the water-mineral-microbe system in and around the Tono uranium deposit, Japan, was studied to evaluate the long-term stability of the redox system. The uranium deposit occurs in the lower part of a Miocene sedimentary rock sequence that unconformably overlies granite. In the groundwater, profiles of redox sensitive solutes such as sulphate and sulphide ions, abundance and viability of microbes, and sulphur isotope ratios of sulphate ions suggest that microbial sulphate reduction involving organic matter and subsequent pyrite precipitation are dominant redox reactions at the depths of the uranium ore bodies. Concentrations of both the sulphate and chloride increase with increasing depth. The dissolved sulphate is surmised to have originated from dissolution of sulphate and sulphide minerals in a geologic marine formation precipitated in marine environments, in the upper part of the sedimentary rocks. Such a redox process in the water-mineral-microbe system is inferred to have continued from the time when the marine formation underwent uplift above sea-level, because sulphate-reducing bacteria can use sulphate ions dissolved in fresh water that infiltrates from the marine formation and organic matter located in the deeper sedimentary rocks. The chloride ion also has a linear relationship with groundwater residence time. from the relationship between sulphate and chloride ion concentrations, the sulphate ion dissolution rates from the marine formation are estimated at about 5.9 x 10{sup -5} mM/yr. Calculations by using the sulphate-S contents of the rocks and the sulphate dissolution rate suggest that microbial sulphate reduction alone could maintain sufficiently reducing conditions to preserve the uranium ore for several hundred thousand years, in the case where a hydrogeological system continues to exist without much change. (author)

  2. Exploring the entrance of proton pathways in cytochrome c oxidase from Paracoccus denitrificans: surface charge, buffer capacity and redox-dependent polarity changes at the internal surface.

    Science.gov (United States)

    Kirchberg, Kristina; Michel, Hartmut; Alexiev, Ulrike

    2013-03-01

    Cytochrome c oxidase (CcO), the terminal oxidase of cellular respiration, reduces molecular oxygen to water. The mechanism of proton pumping as well as the coupling of proton and electron transfer is still not understood in this redox-linked proton pump. Eleven residues at the aqueous-exposed surfaces of CcO from Paracoccus denitrificans have been exchanged to cysteines in a two-subunit base variant to yield single reactive cysteine variants. These variants are designed to provide unique labeling sites for probes to be used in spectroscopic experiments investigating the mechanism of proton pumping in CcO. To this end we have shown that all cysteine variants are enzymatically active. Cysteine positions at the negative (N-) side of the membrane are located close to the entrance of the D- and K-proton transfer pathways that connect the N-side with the catalytic oxygen reduction site. Labeling of the pH-indicator dye fluorescein to these sites allowed us to determine the surface potential at the cytoplasmic CcO surface, which corresponds to a surface charge density of -0.5 elementary charge/1000Å(2). In addition, acid-base titrations revealed values of CcO buffer capacity. Polarity measurements of the label environment at the N-side provided (i) site-specific values indicative of a hydrophilic and a more hydrophobic environment dependent on the label position, and (ii) information on a global change to a more apolar environment upon reduction of the enzyme. Thus, the redox state of the copper and heme centers inside the hydrophobic interior of CcO affect the properties at the cytoplasmic surface. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Redox buffer capacity of sedimentary rocks around uranium deposit. Study of water-mineral-microbe system at the Tono uranium deposit, Japan

    International Nuclear Information System (INIS)

    Iwatsuki, Teruki; Murakami, Yuki; Hama, Katsuhiro; Naganuma, Takeshi

    2003-01-01

    The redox buffer capacity of the water-mineral-microbe system in and around the Tono uranium deposit, Japan, was studied to evaluate the long-term stability of the redox system. The uranium deposit occurs in the lower part of a Miocene sedimentary rock sequence that unconformably overlies granite. In the groundwater, profiles of redox sensitive solutes such as sulphate and sulphide ions, abundance and viability of microbes, and sulphur isotope ratios of sulphate ions suggest that microbial sulphate reduction involving organic matter and subsequent pyrite precipitation are dominant redox reactions at the depths of the uranium ore bodies. Concentrations of both the sulphate and chloride increase with increasing depth. The dissolved sulphate is surmised to have originated from dissolution of sulphate and sulphide minerals in a geologic marine formation precipitated in marine environments, in the upper part of the sedimentary rocks. Such a redox process in the water-mineral-microbe system is inferred to have continued from the time when the marine formation underwent uplift above sea-level, because sulphate-reducing bacteria can use sulphate ions dissolved in fresh water that infiltrates from the marine formation and organic matter located in the deeper sedimentary rocks. The chloride ion also has a linear relationship with groundwater residence time. from the relationship between sulphate and chloride ion concentrations, the sulphate ion dissolution rates from the marine formation are estimated at about 5.9 x 10 -5 mM/yr. Calculations by using the sulphate-S contents of the rocks and the sulphate dissolution rate suggest that microbial sulphate reduction alone could maintain sufficiently reducing conditions to preserve the uranium ore for several hundred thousand years, in the case where a hydrogeological system continues to exist without much change. (author)

  4. Much ado about aha!: Insight problem solving is strongly related to working memory capacity and reasoning ability.

    Science.gov (United States)

    Chuderski, Adam; Jastrzębski, Jan

    2018-02-01

    A battery comprising 4 fluid reasoning tests as well as 13 working memory (WM) tasks that involved storage, recall, updating, binding, and executive control, was applied to 318 adults in order to evaluate the true relationship of reasoning ability and WM capacity (WMC) to insight problem solving, measured using 40 verbal, spatial, math, matchstick, and remote associates problems (insight problems). WMC predicted 51.8% of variance in insight problem solving and virtually explained its almost isomorphic link to reasoning ability (84.6% of shared variance). The strong link between WMC and insight pertained generally to most WM tasks and insight problems, was identical for problems solved with and without reported insight, was linear throughout the ability levels, and was not mediated by age, motivation, anxiety, psychoticism, and openness to experience. In contrast to popular views on the sudden and holistic nature of insight, the solving of insight problems results primarily from typical operations carried out by the basic WM mechanisms that are responsible for the maintenance, retrieval, transformation, and control of information in the broad range of intellectual tasks (including fluid reasoning). Little above and beyond WM is unique about insight. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  5. On the use of dimensionless parameters in acid-base theory: VI. The buffer capacities of equimolar binary mixtures of monovalent weak protolytes as compared to that of bivalent protolytes.

    Science.gov (United States)

    Rilbe, H

    1994-05-01

    The general equation for the relative molar buffer capacity, earlier shown to be valid for bivalent acids, bases, and ampholytes, is shown to hold also for equimolar, binary mixtures of monovalent protolytes if only the parameter s = square root of K1'/4K2' is exchanged for t = s + 1/4s. The same applies to the equations for the mean valence of the two classes of protolytes. As a consequence thereof, the titration and buffer capacity curves of a bivalent protolyte are identical with those of a monovalent protolyte with a pK' value equal to the with those of a monovalent protolyte with a pK' value equal to square root of K1'K2' of the bivalent one (the isoprotic point of an ampholyte). For a hypothetical bivalent acid, base, or ampholyte with s = 1, delta pK' = log 4, this implies that the intrinsic rather than the hybrid dissociation constants are responsible for the titration and buffer capacity curves.

  6. Effect of heavy metals on pH buffering capacity and solubility of Ca, Mg, K, and P in non-spiked and heavy metal-spiked soils.

    Science.gov (United States)

    Najafi, Sarvenaz; Jalali, Mohsen

    2016-06-01

    In many parts of the world, soil acidification and heavy metal contamination has become a serious concern due to the adverse effects on chemical properties of soil and crop yield. The aim of this study was to investigate the effect of pH (in the range of 1 to 3 units above and below the native pH of soils) on calcium (Ca), magnesium (Mg), potassium (K), and phosphorus (P) solubility in non-spiked and heavy metal-spiked soil samples. Spiked samples were prepared by cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) as chloride salts and incubating soils for 40 days. The pH buffering capacity (pHBC) of each sample was determined by plotting the amount of H(+) or OH(-) added (mmol kg(-1)) versus the related pH value. The pHBC of soils ranged from 47.1 to 1302.5 mmol kg(-1) for non-spiked samples and from 45.0 to 1187.4 mmol kg(-1) for spiked soil samples. The pHBC values were higher in soil 2 (non-spiked and spiked) which had higher calcium carbonate content. The results indicated the presence of heavy metals in soils generally decreased the solution pH and pHBC values in spiked samples. In general, solubility of Ca, Mg, and K decreased with increasing equilibrium pH of non-spiked and spiked soil samples. In the case of P, increasing the pH to about 7, decreased the solubility in all soils but further increase of pH from 7, enhanced P solubility. The solubility trends and values for Ca, Mg, and K did not differed significantly in non-spiked and spiked samples. But in the case of P, a reduction in solubility was observed in heavy metal-spiked soils. The information obtained in this study can be useful to make better estimation of the effects of soil pollutants on anion and cation solubility from agricultural and environmental viewpoints.

  7. Calculation of the total plasma concentration of nonvolatile weak acids and the effective dissociation constant of nonvolatile buffers in plasma for use in the strong ion approach to acid-base balance in cats.

    Science.gov (United States)

    McCullough, Sheila M; Constable, Peter D

    2003-08-01

    To determine values for the total concentration of nonvolatile weak acids (Atot) and effective dissociation constant of nonvolatile weak acids (Ka) in plasma of cats. Convenience plasma samples of 5 male and 5 female healthy adult cats. Cats were sedated, and 20 mL of blood was obtained from the jugular vein. Plasma was tonometered at 37 degrees C to systematically vary PCO2 from 8 to 156 mm Hg, thereby altering plasma pH from 6.90 to 7.97. Plasma pH, PCO2, and concentrations of quantitatively important strong cations (Na+, K+, and Ca2+), strong anions (Cl-, lactate), and buffer ions (total protein, albumin, and phosphate) were determined. Strong ion difference was estimated from the measured strong ion concentrations and nonlinear regression used to calculate Atot and Ka from the measured pH and PCO2 and estimated strong ion difference. Mean (+/- SD) values were as follows: Atot = 24.3 +/- 4.6 mmol/L (equivalent to 0.35 mmol/g of protein or 0.76 mmol/g of albumin); Ka = 0.67 +/- 0.40 x 10(-7); and the negative logarithm (base 10) of Ka (pKa) = 7.17. At 37 degrees C, pH of 7.35, and a partial pressure of CO2 (PCO2) of 30 mm Hg, the calculated venous strong ion difference was 30 mEq/L. These results indicate that at a plasma pH of 7.35, a 1 mEq/L decrease in strong ion difference will decrease pH by 0.020, a 1 mm Hg decrease in PCO2 will increase plasma pH by 0.011, and a 1 g/dL decrease in albumin concentration will increase plasma pH by 0.093.

  8. Buffers Plus

    Science.gov (United States)

    Ramette, Richard W.

    1998-11-01

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

  9. Kinetic buffers.

    Science.gov (United States)

    Alibrandi, Giuseppe; Fabbrizzi, Luigi; Licchelli, Maurizio; Puglisi, Antonio

    2015-01-12

    This paper proposes a new type of molecular device that is able to act as an inverse proton sponge to slowly decrease the pH inside a reaction vessel. This makes the automatic monitoring of the concentration of pH-sensitive systems possible. The device is a composite formed of an alkyl chloride, which kinetically produces acidity, and a buffer that thermodynamically modulates the variation in pH value. Profiles of pH versus time (pH-t plots) have been generated under various experimental conditions by computer simulation, and the device has been tested by carrying out automatic spectrophotometric titrations, without using an autoburette. To underline the wide variety of possible applications, this new system has been used to realize and monitor HCl uptake by a di-copper(II) bistren complex in a single run, in a completely automatic experiment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Geochronological reconstruction of the long-term inflow of 137Cs to the Black Sea from mountain and lowland rivers and comparison of the buffer capacity of watersheds

    International Nuclear Information System (INIS)

    Gulin, S.B.; Polikarpov, G.G.; Osvach, I.; Marten, Zh.-M.

    2002-01-01

    The trends of radionuclide discharge from the Danube and Coruh rivers were traced using the 137 Cs deposition records in the adjacent Black Sea sediments. The 137 Cs-derived dating showed that the maximum discharge of 137 Cs from the Coruh was delayed for 14 years relative to the date of the Chernobyl accident, reflecting a buffer effect of watershed soils. This transit time is 3 and 1.5 times langer than that in the Danube and Dnieper, respectively, indicating a difference in retention processes in these mountain and lowland catchment basins. The 137 Cs profile in Coruh sediments showed the penetration of 137 Cs to much greater depth than it would be expected from the 137 Cs fallout chronology, suggesting the sediment mixing at a rate of 1.3 cm 2 y -1 . This value was used to evaluate the deposition chronology of bomb 137 Cs, applying the model developed for pulse fallout case. The higher measured activities of 137 Cs in the upper sediments, relative to modelled data, may be explained by an additional 137 Cs input with eroded soil particles. Subtracting the measured and modelled data allows the differentiation of 137 Cs trends of the flood-induced discharge and the slower transit of 137 Cs from the catchment basin

  11. The role of complement receptor type 1 (CR1, CD35) in determining the cellular distribution of opsonized immune complexes between whole blood cells: kinetic analysis of the buffering capacity of erythrocytes

    DEFF Research Database (Denmark)

    Nielsen, C H; Matthiesen, S H; Lyng, I

    1997-01-01

    Erythrocytes (E) express complement receptor, type 1 (CR1, CD35), by which they bind opsonized immune complexes (IC) in competition with leucocytes expressing higher numbers of CR1 as well as other complement- and Fc-receptors. This may prevent inappropriate activation of phagocytic cells. We......-bound IC were associated with E from 1 to 5 min of incubation, decreasing to 12 +/- 13% after 40 min. Upon comparison of the IC-binding to leucocytes in whole blood with that of isolated leucocytes we found that E, despite their extensive early complex uptake, only reduced the IC......-deposition on polymorphonuclear leucocytes (PMN) by 61 +/- 26% after 30 seconds of incubation and 47 +/- 14% after 5 min. During the subsequent 10 min, this buffering capacity of E was essentially abolished E restricted the initial IC-binding to B cells by 73 +/- 19%, but from 3 min of incubation the presence of E promoted...

  12. Thermodynamic evaluation of the impact of strongly swelling polymer hydrogels with ionic silver on the water retention capacity of sandy substrate

    Science.gov (United States)

    Smagin, A. V.

    2017-01-01

    The impact of two types of strongly swelling polymer hydrogel (SSPH) on the water retention capacity of quartz sand in pure water and Ag+ solutions (10-100 mg/l) has been studied by using a centrifugation method in a wide range of thermodynamic water potential (Gibbs energy) from 0 to 3030 J/kg. The experimental data for the water retention curves (WRC) were estimated by the van Genuchten model. Both hydrogels - the Aquasorb preparation (Germany) with hydrophilic properties and high degree of swelling in pure water (700-1000 g H2O/g) and the new Russian amphiphilic SSPH with a peat filler (degree of swelling 500-700 g H2O/g) were very effective as water adsorbing soil conditioners in relatively small doses from 0.05 to 0.3% per mass of dry (105°C) soil substrate. The water retention capacity of sandy substrate increases under the influence of SSPH with 2-3 times up to the level of native loamy sands and loams. Adding Ag+ to the water solution results just for the highest concentration of SSPH (0.3%) and iconic silver (100 mg/l) in a significant decrease of the water retention in the soil-gel compositions.

  13. Unstimulated salivary flow rate, pH and buffer capacity of saliva in healthy volunteers Débito basal, pH y capacidad tampón de la secreción salivar en sujetos sanos

    Directory of Open Access Journals (Sweden)

    C. Fenoll-Palomares

    2004-11-01

    Full Text Available Objectives: to assess the salivary flow rate, pH, and buffer capacity of healthy volunteers, and their relationships with age, gender, obesity, smoking, and alcohol consumption, and to establish the lower-end value of normal salivary flow (oligosialia. Methods: a prospective study was conducted in 159 healthy volunteers (age > 18 years, absence of medical conditions that could decrease salivary flow. Unstimulated whole saliva was collected during ten minutes, and salivary flow rate (ml/min, pH, and bicarbonate concentration (mmol/l were measured using a Radiometer ABL 520. The 5 percentile of salivary flow rate and bicarbonate concentration was considered the lower limit of normality. Results: median salivary flow rate was 0.48 ml/min (range: 0.1-2 ml/min. Age younger than 44 years was associated with higher flow rates (OR 2.10. Compared with women, men presented a higher flow rate (OR 3.19 and buffer capacity (OR 2.81. Bicarbonate concentration correlated with salivary flow rate. The lower-end values of normal flow rate and bicarbonate concentration were 0.15 ml/min and 1.800 mmol/l, respectively. The presence of obesity, smoking, and alcohol consumption did not influence salivary parameters. Conclusions: in healthy volunteers, salivary flow rate depends on age and gender, and correlates with buffer capacity. Obesity, smoking, and alcohol use do not influence salivary secretion.Objetivos: conocer el débito, pH y capacidad tampón de la saliva en sujetos sanos y sus relaciones con edad, sexo, obesidad y hábitos tabáquico y alcohólico, así como establecer la definición de hiposialia. Métodos: estudio observacional prospectivo en 159 voluntarios sanos (> 18 años, sin factores conocidos que disminuyan la secreción salivar. Se ha recogido la saliva total, sin estímulo, durante 10 minutos, determinando su débito (ml/min, pH y capacidad tampón (concentración de bicarbonato en mmol/l mediante autoanalizador Radiometer ABL 520. Se han

  14. SODR Memory Control Buffer Control ASIC

    Science.gov (United States)

    Hodson, Robert F.

    1994-01-01

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

  15. Pressure buffering by the tympanic membrane. In vivo measurements of middle ear pressure fluctuations during elevator motion.

    Science.gov (United States)

    Padurariu, Simona; de Greef, Daniël; Jacobsen, Henrik; Nlandu Kamavuako, Ernest; Dirckx, Joris J; Gaihede, Michael

    2016-10-01

    The tympanic membrane (TM) represents a pressure buffer, which contributes to the overall pressure regulation of the middle ear (ME). This buffer capacity is based on its viscoelastic properties combined with those of the attached ossicular chain, muscles and ligaments. The current work presents a set of in vivo recordings of the ME pressure variations normally occurring in common life: elevator motion. This is defined as a situation of smooth ambient pressure increase or decrease on a limited range and at a low rate of pressure change. Based on these recordings, the purpose was a quantitative analysis of the TM buffer capacity including the TM compliance. The pressure changes in seven normal adult ME's with intact TM's were continuously recorded directly inside the ME cavity during four different elevator trips using a high precision instrument. The TM buffer capacity was determined by the ratio between the changes in ME and the ambient pressure. Further, the ME volumes were calculated by Boyle's Law from pressure recordings during inflation-deflation tests; subsequently the TM compliance could also be calculated. Finally, the correlation between the ME volume and buffer function was determined. Twenty-one elevator trips could be used for the analysis. The overall mean TM pressure buffering capacity was 23.3% (SEM = 3.4), whereas the mean overall compliance was 28.9 × 10 -3  μL/Pa (SEM = 4.8). A strong negative linear correlation was found between the TM buffer capacity and the ME volumes (R 2  = 0.92). These results were in fair agreement with the literature obtained in clinical as well as temporal bone experiments, and they provide an in vivo reference for the normal ME function as well as for ME modeling. The TM buffer capacity was found more efficient in smaller mastoids. Possible clinical implications are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. The buffer effect in neutral electrolyte supercapacitors

    DEFF Research Database (Denmark)

    Thrane Vindt, Steffen; Skou, Eivind M.

    2016-01-01

    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....

  17. Titration curves: a useful instrument for assessing the buffer systems of acidic mining waters.

    Science.gov (United States)

    Totsche, Oliver; Fyson, Andrew; Kalin, Margarete; Steinberg, Christian E W

    2006-07-01

    The acidification of mine waters is generally caused by metal sulfide oxidation, related to mining activities. These waters are characterized by low pH and high acidity due to strong buffering systems. The standard acidity parameter, the Base Neutralization Capacity (BNC), is determined by endpoint titration, and reflects a cumulative parameter of both hydrogen ions and all buffering systems, but does not give information on the individual buffer systems. We demonstrate that a detailed interpretation of titration curves can provide information about the strength of the buffering systems. The buffering systems are of importance for environmental studies and treatment of acidic mining waters. Titrations were carried out by means of an automatic titrator using acidic mining waters from Germany and Canada. The curves were interpreted, compared with each other, to endpoint titration results and to elemental concentrations contained therein. The titration curves were highly reproducible, and contained information about the strength of the buffer systems present. Interpretations are given, and the classification and comparison of acidic mining waters, by the nature and strength of their buffering systems derived from titration curves are discussed. The BNC-values calculated from the curves were more precise than the ones determined by the standard endpoint titration method. Due to the complex buffer mechanisms in acidic mining waters, the calculation of major metal concentrations from the shape of the titration curve resulted in estimates, which should not be confused with precise elemental analysis results. Titration curves provide an inexpensive, valuable and versatile tool, by which to obtain sophisticated information of the acidity in acidic water. The information about the strength of the present buffer systems can help to understand and document the complex nature of acidic mining water buffer systems. Finally, the interpretation of titration curves could help to

  18. Buffer Zone Fact Sheets

    Science.gov (United States)

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

  19. Capacidade tamponante, pH e consistência das fezes em equinos submetidos à sobrecarga dietética com amido Buffer capacity, pH and faeces consistency in horses submitted to dietetic starch overload

    Directory of Open Access Journals (Sweden)

    Tiago Marques dos Santos

    2009-09-01

    Full Text Available Este trabalho teve como objetivo avaliar a capacidade tamponante (CT, o pH e a consistência das fezes em equinos submetidos à sobrecarga dietética com amido. Seis equinos adultos foram submetidos à sobrecarga com infusão gástrica de 17,6g de amido kg-1 de peso corporal através de sonda nasogástrica. Amostras fecais foram coletadas, antes e quatro, oito, 12, 16, 20, 24, 28, 32 e 36 horas pós-sobrecarga, e imediatamente submetidas à avaliação do pH, da CT e da consistência. Os resultados de pH foram comparados pelo teste t de student (P0,05 no pH fecal ao longo de 36 horas pós-sobrecarga, com valores médios variando de 6,09 a 4,46. A partir do modelo pH = 6,083 - 0,003t - 0,001t² (R² = 0,634, houve decréscimo de 0,004 no pH fecal a cada hora, de 0,028 a cada quatro horas e de 1,404 ao final de 36 horas após a sobrecarga, respectivamente. Além do pH, houve redução (PThis study aimed to evaluate buffer capacity (BC, pH and faeces consistency of horses submitted to dietetic starch overload. Six crossbreed mature horses were submitted to starch overload with gastric infusion of 17.6g starch kg-1 body weight through nasogastric tube. Faecal samples were collected, before and at 4, 8, 12, 16, 20, 24, 28, 32 and 36 hours post-overload, and immediately submitted to evaluation of pH, BC and consistency. The pH data were compared by t student test (P0.05, with means values varying from 6.09 to 4.46. Based on the model pH = 6.083 - 0.003t - 0.001t² (R² = 0.634, faecal pH decreased 0.004 per hour, 0.028 to each four hours and 1.404 at 36 hours after overload, respectively. As pH, faeces BC decreased (P<0.05 in function of the time after overload. Positive relationship was observed (r = 0.65; P<0.0001 between pH and BC of faeces. All horses presented normal consistency faeces (score 3 until eight hours after overload, following by reduction (P<0.05 up to 36 hours. Results demonstrated that starch overload reduce faecal consistency

  20. Buffer capacity of 4% succinylated gelatin does not provide any advantages over acidic 6% hydroxyethyl starch 130/0.4 for acid-base balance during experimental mixed acidaemia in a porcine model.

    Science.gov (United States)

    Esche, V; Russ, M; Melzer, S; Grossmann, B; Boemke, W; Unger, J K

    2008-11-01

    Four percent gelatine is an alkaline compound due to NH2 groups, whereas 6% hydroxyethyl starch 130/0.4 (HES130) has acidic features. We investigated whether these solutions lead to differences in acid-base balance in pigs during acidaemia and correction of pH. Anaesthetized pigs were randomized to HES130 or gelatine infusion (n = 5 per group). Animals received acid infusion (0.4 M solution of lactic acid and HCl diluted in normal saline) and low tidal volume ventilation (6-7 mL kg(-1), PaCO2 of 80-85 mmHg, pH 7.19-7.24). Measurements were made before and after induction of acidaemia, before and after correction of pH with haemofiltration (continuous venovenous haemofiltration) and tris-hydroxymethylaminomethane infusion. We measured parameters describing acid-base balance according to Stewart's approach, ketone body formation, oxygen delivery, haemodynamics, diuresis and urinary pH. Acid-base balance did not differ significantly between the groups. In HES130-treated pigs, the haemodilution-based drop of haemoglobin (1.4 +/- 1.0 g dL(-1), median +/- SD) was paralleled by an increase in the cardiac output (0.5 +/- 0.4 L min(-1). Lacking increases in cardiac output, gelatine-treated pigs demonstrated a reduction in oxygen delivery (149.4 +/- 106.0 mL min(-1)). Tris-hydroxymethylaminomethane volumes required for pH titration to desired values were significantly higher in the gelatine group (0.7 +/- 0.1 mL kg(-1) h(-1) vs. HES130: 0.5 +/- 0.2 mL kg(-1) h(-1)). The buffer capacity of gelatine did not lead to favourable differences in acid-base balance in comparison to HES130.

  1. Using fluorescent dyes as proxies to study herbicide removal by sorption in buffer zones.

    Science.gov (United States)

    Dollinger, Jeanne; Dagès, Cécile; Voltz, Marc

    2017-04-01

    The performance of buffer zones for removing pesticides from runoff water varies greatly according to landscape settings, hydraulic regime, and system design. Evaluating the performance of buffers for a range of pesticides and environmental conditions can be very expensive. Recent studies suggested that the fluorescent dyes uranine and sulforhodamine B could be used as cost-effective surrogates of herbicides to evaluate buffer performance. However, while transformation mechanisms in buffers have been extensively documented, sorption processes of both dyes have rarely been investigated. In this study, we measured the adsorption, desorption, and kinetic sorption coefficients of uranine and sulforhodamine B for a diverse range of buffer zone materials (soils, litters, plants) and compared the adsorption coefficients (Kd) to those of selected herbicides. We also compared the global sorption capacity of 6 ditches, characterized by varying proportions of the aforementioned materials, between both dyes and a set of four herbicides using the sorption-induced pesticide retention indicator (SPRI). We found that both the individual Kd of uranine for the diverse buffer materials and the global sorption capacity of the ditches are equivalent to those of the herbicides diuron, isoproturon, and metolachlor. The Kd of sulforhodamine B on plants and soils are equivalent to those of glyphosate, and the global sorption capacities of the ditches are equivalent for both molecules. Hence, we demonstrate for the first time that uranine can be used as a proxy of moderately hydrophobic herbicides to evaluate the performance of buffer systems, whereas sulforhodamine B can serve as a proxy for more strongly sorbing herbicides.

  2. 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.

  3. 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.

  4. Shared filtering processes link attentional and visual short-term memory capacity limits.

    Science.gov (United States)

    Bettencourt, Katherine C; Michalka, Samantha W; Somers, David C

    2011-09-30

    Both visual attention and visual short-term memory (VSTM) have been shown to have capacity limits of 4 ± 1 objects, driving the hypothesis that they share a visual processing buffer. However, these capacity limitations also show strong individual differences, making the degree to which these capacities are related unclear. Moreover, other research has suggested a distinction between attention and VSTM buffers. To explore the degree to which capacity limitations reflect the use of a shared visual processing buffer, we compared individual subject's capacities on attentional and VSTM tasks completed in the same testing session. We used a multiple object tracking (MOT) and a VSTM change detection task, with varying levels of distractors, to measure capacity. Significant correlations in capacity were not observed between the MOT and VSTM tasks when distractor filtering demands differed between the tasks. Instead, significant correlations were seen when the tasks shared spatial filtering demands. Moreover, these filtering demands impacted capacity similarly in both attention and VSTM tasks. These observations fail to support the view that visual attention and VSTM capacity limits result from a shared buffer but instead highlight the role of the resource demands of underlying processes in limiting capacity.

  5. Optimization of protein buffer cocktails using Thermofluor.

    Science.gov (United States)

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

    2013-02-01

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

  6. Redox Buffer Strength

    Science.gov (United States)

    de Levie, Robert

    1999-04-01

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

  7. USE OF STRONG ACID RESIN PUROLITE C100E FOR REMOVING PERMANENT HARDNESS OF WATER – FACTORS AFFECTING CATIONIC EXCHANGE CAPACITY

    Directory of Open Access Journals (Sweden)

    BOGDAN BANDRABUR

    2013-12-01

    Full Text Available This paper experimentally investigates the performance and capacity of Purolite C100E commercial resin recommended for water softening applications in the food industry. The practical ion exchange capacity and the softening process efficiency are studied in batch mode as a function of the sorption specific process factors. Optimum operation conditions were determined as initial pH 7.1, resin dose 8 g dry resin•L-1, temperature 25 oC, contact time of 360 min, and in those conditions the retention capacity for the Ca2+ ions is 17.18 mg•g-1 that corresponds to a removal efficiency equal to 85.7%.

  8. FRICTION BUFFER STOP DESIGN

    Directory of Open Access Journals (Sweden)

    Petr Guziur

    2017-08-01

    Full Text Available Friction buffer stops are the favoured construction of buffer stop, mainly due to its high resistance and variety of layout. Last but not least is its manner of deceleration induced upon impact and during the braking what makes it smart solution in railway transport safety. The general approach of designing buffer stops is via usage of the kinetic energy and its conversion into work. Paper describes input parameters such as train velocity or buffer stop vicinity which is expressed by the safety coefficient implanted within the calculation. Furthermore, the paper shows the principle of calculation the friction buffer stop work, or to be more precise, the work of its braking jaws and optionally the work of additional braking jaws located behind the buffer stop. Last section of the paper is focused on the examples of designing friction buffer stops, points out the main complications and shows the charts of relation amongst braking distance, kinetic energy and braking force and the charts of relation between deceleration rate and braking distance.

  9. A buffer diverter system

    Science.gov (United States)

    Foster, J. C., Jr.

    1985-07-01

    The prevention of sympathetic detonations between donor and acceptor bombs, which are stored lying horizontally lying parallel to each other, is accomplished using a buffer diverter system. One example of a buffer diverter system is a pair of molded concrete bases, each supporting a horizontal bomb and conforming to the shape of its respective bomb up to its horizontal centerline. In the first example, the entire space between the two molded concrete bases and bombs is filled in with a buffer which has sufficient width to attenuate the shock of detonation down pressure levels below a pressure threshold needed to induce an acceptor bomb to sympathetically detonate. In another example of a buffer diverter system, the buffer is replaced with a diverter. The diverter is an I-beam which abuts each bomb at its horizontal centerline and runs the length of the two bombs. The I-beam has the same width as the buffer, but its surface area presented to each bomb is nearly the minimum required to deflect fragments from the silhouette of the acceptor bomb.

  10. Analysis of diffusive mass transport in a cracked buffer

    International Nuclear Information System (INIS)

    Garisto, N.C.; Garisto, F.

    1989-11-01

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

  11. Buffering action of human dentin in vitro.

    Science.gov (United States)

    Camps, J; Pashley, D H

    2000-01-01

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

  12. Buffer design 2012

    International Nuclear Information System (INIS)

    Juvankoski, M.

    2013-08-01

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

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

    Science.gov (United States)

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

    2006-08-09

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

  14. Expression of DIAPH1 is up-regulated in colorectal cancer and its down-regulation strongly reduces the metastatic capacity of colon carcinoma cells.

    Science.gov (United States)

    Lin, Yuan-Na; Izbicki, Jakob R; König, Alexandra; Habermann, Jens K; Blechner, Christine; Lange, Tobias; Schumacher, Udo; Windhorst, Sabine

    2014-04-01

    In most cases, metastatic colorectal cancer is not curable, thus new approaches are necessary to identify novel targets for colorectal cancer therapy. Actin-binding-proteins (ABPs) directly regulate motility of metastasising tumor cells, and for cortactin an association with colon cancer metastasis has been already shown. However, as its depletion only incompletely inhibits metastasis, additional, more suitable cellular targets have to be identified. Here we analyzed expression of the ABPs, DIAPH1, VASP, N-WASP, and fascin in comparison with cortactin and found that, besides cortactin, DIAPH1 was expressed with the highest frequency (63%) in colorectal cancer. As well as cortactin, DIAPH1 was not detectable in normal colon tissue and expression of both proteins was positively correlated with metastasis of colorectal cancer. To analyse the mechanistic role of DIAPH1 for metastasis of colon carcinoma cells in comparison with cortactin, expression of the proteins was stably down-regulated in the human colon carcinoma cell lines HT-29, HROC-24 and HCT-116. Analysis of metastasis of colon carcinoma cells in SCID mice revealed that depletion of DIAPH1 reduced metastasis 60-fold and depletion of cortactin 16-fold as compared with control cells. Most likely the stronger effect of DIAPH1 depletion on colon cancer metastasis is due to the fact that in vitro knock down of DIAPH1 impaired all steps of metastasis; adhesion, invasion and migration while down-regulation of cortactin only reduced adhesion and invasion. This very strong reducing effect of DIAPH1 depletion on colon carcinoma cell metastasis makes the protein a promising therapeutic target for individualized colorectal cancer therapy. © 2013 UICC.

  15. The SVT Hit Buffer

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  16. 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....

  17. Labview virtual instruments for calcium buffer calculations.

    Science.gov (United States)

    Reitz, Frederick B; Pollack, Gerald H

    2003-01-01

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

  18. Buffer sizing to reduce interference and increase throughput of real-time stream processing applications

    NARCIS (Netherlands)

    Kurtin, Philip Sebastian; Geuns, S.J.; Hausmans, J.P.H.M.; Bekooij, Marco Jan Gerrit

    2015-01-01

    Existing temporal analysis and buffer sizing techniques for real-time stream processing applications ignore that FIFO buffers bound interference between tasks on the same processor. By considering this effect it can be shown that a reduction of buffer capacities can result in a higher throughput.

  19. Buffer Zone Sign Template

    Science.gov (United States)

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

  20. Buffer Zone, Nicosia

    OpenAIRE

    Sorensen, Marie Louise

    2010-01-01

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

  1. Evidence of a Strong Correlation Between Oxygen Nonstoichiometry (d) and Oxygen Uptake Capacities of La1-xSrxCo0.2Fe0.8O3-d oxides (0.1 < Srx < 0.4)

    International Nuclear Information System (INIS)

    Magnone, Edoardo; Kim, Jung Ryoel; Park, Jung Hoon; Park, Seongkyu

    2014-01-01

    The communication provided clear evidence of a strong correlation between the nonstoichiometry oxygen content (d) or oxygen content (3-d) and the maximum oxygen uptake capacity of La 1-x Sr x Co 0.2 Fe 0.8 O 3-d oxides (0.1 < x < 0.4). The results may be considered as a provisional basis for further research, allowing the prediction of the oxygen uptake capacities at low temperature by easy determination of oxygen contents. Recently, there has been a growing interest in utilizing nonstoichiometric La 1-x Sr x Co 1-y Fe y O 3-d perovskite-type oxide as sorbents for high-temperature production of oxygen-enriched carbon dioxide stream. During the past decades, many studies have been conducted on these solid solutions, and in order to achieve higher oxygen uptake capacities, the La 3+ lanthanide was substituted by bivalent Sr 2+ alkaline-earth ions to decrease the ionicity of the Ln.O bond which could result in an increased number of hole

  2. Preliminary findings on the correlation of saliva pH, buffering ...

    African Journals Online (AJOL)

    2017-03-07

    Mar 7, 2017 ... findings on the correlation of saliva pH, buffering capacity, flow rate and consistency in ... saliva collection. The pH was measured directly using a pH meter. The buffering capacity was determined using a quantitative method which involved the addition of .... 2 was the normal deviate for two-tailed alternative.

  3. Buffers for biomass production in temperate European agriculture

    DEFF Research Database (Denmark)

    Christen, Benjamin; Dalgaard, Tommy

    2013-01-01

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

  4. 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.

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

    Science.gov (United States)

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

    2008-09-01

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

  6. Thermal and Carbon Dioxide Inactivation of Alkaline Phosphatase in Buffer and Milk

    Directory of Open Access Journals (Sweden)

    Osman Erkmen

    2004-01-01

    Full Text Available The effects of temperature and CO2 treatment on the inactivation of alkaline phosphatase (ALP were studied. The thermal stability of ALP was found to be significantly (P< 0.05 different in glycine/NaOH buffer, pasteurized milk and raw milk. ALP was completely inactivated in the buffer at 60, 70 and 80 °C but approximately 12 % of activity was present at 50 °C after 55 min of treatment. The time required for complete inactivation of the enzyme in the buffer was reduced from 50 to 4 min as temperature increased from 60 to 80 °C. Complete inactivation of the enzyme in pasteurized milk was achieved at 70 and 80 °C but 28 and 15 % of ALP activity was still present at 50 and 60 °C after 120 min of treatment. Inactivation time for raw milk was reduced nearly 18-fold by increasing temperature from 50 to 70 °C. ALP in the buffer exposed to CO2 (under atmospheric pressure treatment at different temperatures showed a decrease in enzyme activity. Inactivation was found to be higher as the temperature increased from 20 to 50 °C. At the end of a 30-min treatment, residual ALP activity was found to be 84 and 19 % at 20 and 50 °C, respectively. Faster drop in pH and enzyme activity occurred within 5 min. The change in pH and enzyme activity dependant on CO2 treatment was not observed in raw milk mainly due to strong buffering capacity of milk.

  7. Buffer moisture protection system

    International Nuclear Information System (INIS)

    Ritola, J.; Peura, J.

    2013-11-01

    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.)

  8. Two-Buffer Simulation Games

    Directory of Open Access Journals (Sweden)

    Milka Hutagalung

    2016-07-01

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

  9. Fertilizantes fosfatados e produção da soja em solos com diferentes capacidades tampão de fosfato Phosphate fertilizers and soybean yield in soils with different phosphate buffer capacities

    Directory of Open Access Journals (Sweden)

    I. Bedin

    2003-08-01

    were determined for each soil. P supply by TS1 and TS2 increased the yields of soybean dry matter and grain. The use of TS's, separately or in mixture with triple superphosphate, provided vegetative growth and production of soybean that is comparable to treatments with triple superphosphate and thermophosphate. The increase in the P capacity factor of the soil restricted the P uptake and contributed to a greater P use efficiency for soybean, leveling off the effect of the treatments.

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

    OpenAIRE

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

    2016-01-01

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

  11. Integrated optical buffers for packet-switched networks

    Science.gov (United States)

    Burmeister, Emily Frances

    Routers form the backbone of the Internet, directing data to the right locations with huge throughput capacity of terabits/second) and very few errors (1 error allowed in 1012 bits). However, as the Internet continues to grow rapidly, so must the capacity of electronic routers, thereby also growing in footprint and power consumption. The energy bill alone has developers looking for an alternate solution. Today's routers can only operate with electrical signals although Internet data is transmitted optically. This requires the data to be converted from the optical domain to the electrical domain and back again. Optical routers have the potential of saving in power by omitting these conversions, but have been held back in part by the lack of a practical optical memory device. This work presents the first integrated optical buffer for next generation optical packet-switched networks. Buffering is required in a router to move packets of data in order to avoid collisions between packets heading to the same destination at the same time. The device presented here uses an InP-based two-by-two switch with a silica waveguide delay to form a recirculating buffer. Packet storage was shown with 98% packet recovery for 5 circulations. Autonomous contention resolution was demonstrated with two buffered channels to show that the technology is a realistic solution for creating multiple element buffers on multiple router ports. This thesis proposes and demonstrates the first integrated optical random access memory, thereby making a great stride toward high capacity optical routers.

  12. Mechanisms of buffer therapy resistance.

    Science.gov (United States)

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

    2014-04-01

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

  13. Moisture buffering phenomenon and its impact on building energy consumption

    DEFF Research Database (Denmark)

    Zhang, Mingjie; Qin, Menghao; Rode, Carsten

    2017-01-01

    Moisture buffering is the ability of surface materials in the indoor environment to moderate the indoor humidity variations through adsorption or desorption. Materials with high moisture buffering capacity could be used to passively control the indoor moisture condition and consequently improve...... the indoor environmental quality and reduce the latent heat load of buildings. In order to characterize the moisture buffering ability of materials, the basic concept of moisture buffer value (MBV) is adopted. The paper first proposes a new mathematical expression of basic MBV, and then introduces...... a theoretical correction factor that could be used together with the MBV to calculate the moisture uptake/release by hygroscopic materials exposed to different types of humidity variations. Secondly, a simplified two-bottle test method is proposed to measure the MBV in the present study. The impact of moisture...

  14. Moisture Buffer Performance of a Fully Furnished Room

    DEFF Research Database (Denmark)

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

    2004-01-01

    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 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...

  15. Railway capacity

    OpenAIRE

    Lavrič, Tadeja

    2012-01-01

    In the first part of the thesis, the concepts of railway capacity and capacity consumption are defined. Experts have in the past defined railway capacity in many different ways. This thesis outlines some definitions of railway capacity and capacity consumption, including the definition of railway capacity in accordance with the UIC code 406 (2004), given by the International Union of Railways in order to standardize the definition of railway capacity. Capacity and capacity consumption are dir...

  16. <strong>OPTIMIZATION OF IMMOBILIZED METAL strong>>ION AFFINITYstrong>> strong>>CHROMATOGRAPHY strong>>FOR strong>>PHOSPHOPEPTIDE ENRICHMENT  PRIOR TO strong>>MASS SPECTROMETRYstrong>

    DEFF Research Database (Denmark)

    Ye, Juanying; Zhang, Xumin; Young, Clifford

    simple procedures.     Methods Tryptic digests of standard phosphoproteins (bovine α,β- casein) and 3 non-phosphoproteins (bovine serum albumin, bovine β-lactoglobulin, and bovine carbonic anhydrase) with different ratios (1:50, 1:200, 1:500, 1:1000) were used for Fe(III)-IMAC (Qiagen Ni-NTA) enrichment.......   Results Fe(III)-IMAC using NTA-silica from Qiagen  showed a better performance than two other commercially available resins under the testing conditions. Increase of the acetonitrile content to 60% in loading and washing buffer significantly improved the specificity of IMAC enrichment. It was demonstrated...

  17. Electrodialysis operation with buffer solution

    Science.gov (United States)

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

    2009-12-15

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

  18. Buffers and vegetative filter strips

    Science.gov (United States)

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

    2008-01-01

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

  19. Heat conductivity of buffer materials

    International Nuclear Information System (INIS)

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

    1994-11-01

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

  20. Programmable pH buffers

    Science.gov (United States)

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

    2017-01-24

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

  1. Carbon dioxide dissociation and buffering in chicken blood during development.

    Science.gov (United States)

    Tazawa, H; Piiper, J

    1984-07-01

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

  2. 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.)

  3. Buffer gas acquisition and storage

    Science.gov (United States)

    Parrish, Clyde F.; Lueck, Dale E.; Jennings, Paul A.

    2001-02-01

    The acquisition and storage of buffer gases (primarily argon and nitrogen) from the Mars atmosphere provides a valuable resource for blanketing and pressurizing fuel tanks and as a buffer gas for breathing air for manned missions. During the acquisition of carbon dioxide (CO2), whether by sorption bed or cryo-freezer, the accompanying buffer gases build up in the carbon dioxide acquisition system, reduce the flow of CO2 to the bed, and lower system efficiency. It is this build up of buffer gases that provide a convenient source, which must be removed, for efficient capture of CO2. Removal of this buffer gas barrier greatly improves the charging rate of the CO2 acquisition bed and, thereby, maintains the fuel production rates required for a successful mission. Consequently, the acquisition, purification, and storage of these buffer gases are important goals of ISRU plans. Purity of the buffer gases is a concern e.g., if the CO2 freezer operates at 140 K, the composition of the inert gas would be approximately 21 percent CO2, 50 percent nitrogen, and 29 percent argon. Although there are several approaches that could be used, this effort focused on a hollow-fiber membrane (HFM) separation method. This study measured the permeation rates of CO2, nitrogen (N2), and argon (Ar) through a multiple-membrane system and the individual membranes from room temperature to 193 K and 10 kPa to 300 kPa. Concentrations were measured with a gas chromatograph. The end result was data necessary to design a system that could separate CO2, N2, and Ar. .

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

    International Nuclear Information System (INIS)

    Cho, D.L.

    1986-01-01

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

  5. Buffer$--An Economic Analysis Tool

    Science.gov (United States)

    Gary Bentrup

    2007-01-01

    Buffer$ is an economic spreadsheet tool for analyzing the cost-benefits of conservation buffers by resource professionals. Conservation buffers are linear strips of vegetation managed for multiple landowner and societal objectives. The Microsoft Excel based spreadsheet can calculate potential income derived from a buffer, including income from cost-share/incentive...

  6. Visual attention capacity

    DEFF Research Database (Denmark)

    Habekost, Thomas; Starrfelt, Randi

    2009-01-01

    Psychophysical studies have identified two distinct limitations of visual attention capacity: processing speed and apprehension span. Using a simple test, these cognitive factors can be analyzed by Bundesen's Theory of Visual Attention (TVA). The method has strong specificity and sensitivity...

  7. Physico-chemical properties of amphoteric, isoelectric, macroreticulate buffers.

    Science.gov (United States)

    Chiari, M; Pagani, L; Righetti, P G

    1991-09-01

    We report here the properties of a new family of resins possessing an amphoteric character and able to strongly buffer at their pI values. They have been adopted as carriers for growth of cells in tissue culture and for hydroponics (Righetti et al. 1991; J. Biotechnol. 17, 169-176) but it is to be expected that such resins could have interesting chromatographic applications. It has been found that such beads [made by incorporating a pK 6.2 weak acrylamido base and a pK 4.6 weak acrylamido acid in a 2:1 ratio (thus with a pI of 6.2) into a neutral polyacrylamide backbone], independently from their initial conditioning (acid- or base-washed), spontaneously seek their equilibrium position (pI value) upon washing off excess titrant. Thus, upon potentiometric titration, they are seen to buffer in both directions of the pH scale (contrary to the behaviour of a pure carboxyl or a pure amino surface, which will exhibit only unidirectional buffering power). From the behaviour of these amphoteric beads when polymerized in the absence or in the presence of salts (0.2 M NaCl), it is hypothesized that, for exerting buffering power, both the buffering ion and its counterion must be incorporated non-randomly in the chain, but as a couple or in close proximity. Upon random incorporation of the two ions, buffering power is lost.

  8. 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....

  9. Evaluation of amine inhibitors for suitability as crevice buffering agents

    International Nuclear Information System (INIS)

    Jayaweera, P.; Hettiarachchi, S.

    1994-03-01

    This report describes the results of a research effort to evaluate the suitability of some selected amines and amino acids as a crevice-buffering agents in pressurized water reactor (PWR) steam generators. The amines may be useful for buffering acid crevices, and the amino acids, because they contain both acidic and basic groups, may be useful for acidic and caustic crevices. Five commercially available amines and two amino acids were studied during this research. The study involved (1) the hydrolysis of these commercially available amines and amino acids, including measurement of their kinetics of decomposition, in simulated steam generator bulk water at 290 C, and (2) determination of their thermal stability in a simulated crevice environment. The study showed that, although the high-molecular-weight amines undergo hydrothermal decomposition, they have a better buffering capacity than their low-molecular-weight counterparts at 290 C. The amines provide effective crevice buffering by increasing the pH of the crevice solution by as much as 2.84 and to 4.24 units in the experimental setup used in this program. It was concluded that polyamines provide excellent buffering of the simulated crevice environment at 290 C and morpholine remains the best low-molecular-weight amine investigated. However, detailed volatility studies of the amines were not considered in this work. Such data would be needed before in-plant testing to ensure that the amines can concentrate in steam generator crevices to the levels assumed in this study

  10. Stability of buffer-free freeze-dried formulations: A feasibility study of a monoclonal antibody at high protein concentrations.

    Science.gov (United States)

    Garidel, Patrick; Pevestorf, Benjamin; Bahrenburg, Sven

    2015-11-01

    We studied the stability of freeze-dried therapeutic protein formulations over a range of initial concentrations (from 40 to 160 mg/mL) and employed a variety of formulation strategies (including buffer-free freeze dried formulations, or BF-FDF). Highly concentrated, buffer-free liquid formulations of therapeutic monoclonal antibodies (mAbs) have been shown to be a viable alternative to conventionally buffered preparations. We considered whether it is feasible to use the buffer-free strategy in freeze-dried formulations, as an answer to some of the known drawbacks of conventional buffers. We therefore conducted an accelerated stability study (24 weeks at 40 °C) to assess the feasibility of stabilizing freeze-dried formulations without "classical" buffer components. Factors monitored included pH stability, protein integrity, and protein aggregation. Because the protein solutions are inherently self-buffering, and the system's buffer capacity scales with protein concentration, we included highly concentrated buffer-free freeze-dried formulations in the study. The tested formulations ranged from "fully formulated" (containing both conventional buffer and disaccharide stabilizers) to "buffer-free" (including formulations with only disaccharide lyoprotectant stabilizers) to "excipient-free" (with neither added buffers nor stabilizers). We evaluated the impacts of varying concentrations, buffering schemes, pHs, and lyoprotectant additives. At the end of 24 weeks, no change in pH was observed in any of the buffer-free formulations. Unbuffered formulations were found to have shorter reconstitution times and lower opalescence than buffered formulations. Protein stability was assessed by visual inspection, sub-visible particle analysis, protein monomer content, charge variants analysis, and hydrophobic interaction chromatography. All of these measures found the stability of buffer-free formulations that included a disaccharide stabilizer comparable to buffer

  11. Unsaturated hydraulic property of buffer material

    International Nuclear Information System (INIS)

    Suzuki, Hideaki; Fujita, Tomoo

    1999-09-01

    After emplacement of the engineered barrier system (EBS), it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanism, infiltration of groundwater from the surrounding rock into the EBS, generation of swelling pressure in the buffer due to water infiltration and the stress imposed by the overburden pressure. These phenomena are not all independent, but can be strongly influenced by, and coupled with, each other. Evaluating these coupled thermo-hydro-mechanical phenomena is important in order to clarify the initial transient behavior of the engineered barrier system within the near-field. This report describes the results on measurement of chemical potential, water diffusivity, and thermal water diffusivity of bentonite that is considered as a candidate material of buffer and on comparison between measurements and theoretical studies for these properties. The following results are identified; (l) The hysteresis of chemical potential in wet and dry conditions for compacted bentonite is not shown clearly. The chemical potential depends on temperature and amount of montmorillonite. When chemical potential of compacted bentonite is zero, the specimen is saturated. The van Genuchten model is applicable to the measured chemical potential of compacted bentonite. (2) The Darcy's law and Philip and de Vries model are applicable to the measured water diffusivity and thermal water diffusivity of compacted bentonite. (author)

  12. Avaliação de fontes de amônia para o tratamento de fenos de gramíneas tropicais. 1. Constituintes da parede celular, poder tampão e atividade ureática Evaluation of ammonia sources to tropical grasses hays treatment. 1. Cell wall contents, buffer capacity and urease activity

    Directory of Open Access Journals (Sweden)

    Ricardo Andrade Reis

    2001-06-01

    Full Text Available Avaliaram-se as alterações da fração fibrosa e as características químicas dos fenos de braquiária decumbens (Brachiaria decumbnes Stapf e jaraguá (Hyparrhenia rufa Ness Stapf não-tratados, tratados com uréia (U-5,4% da MS, uréia (UL-5,4% da MS mais labe-labe (Lablab purpureus L. Sweet, cv. Highworth-3,0% da MS ou amônia anidra (NH3 -3,0% da MS. O tratamento químico com uréia ou NH3 aumentou o pH e a digestibilidade in vitro verdadeira dos fenos. A amonização não alterou os teores de fibra em detergente ácido e celulose, mas diminuiu os de fibra em detergente neutro, hemicelulose e lignina. O uso do labe-labe como fonte adicional de urease não aumentou a eficiência da uréia no tratamento dos volumosos. As avaliações do conteúdo de umidade, do poder tampão e da atividade ureática são técnicas que podem auxiliar na previsão das respostas dos volumosos à amonização com o uso de uréia.The experiment was conducted to evaluate the changes on the chemical composition and the in vitro dry matter digestibility (IVDMD of the Brachiaria decumbens Stapf, jaraguá (Hyparrhenia rufa Ness Stapf hays, untreated, treated with urea (5.4% DM, urea (UL-5.4% DM and lab lab (Lablab purpureus L. Sweet, cv. Highworth-3.0% DM; and anhydrous ammonia (NH3 3.0% DM. The chemical treatment increased the pH and the in vitro digestibility of the hays Ammoniation did not affect ADF and cellulose contents. The NDF, hemicellulose and lignin contents decreased due to ammoniation with NH3. The urea utilization had the same efficiency that anhydrous ammonia on the hemicellulose content of the hays. The use of an external source of urease did not affect the urea treatment efficiency. The evaluation of the chemical characteristics of the forages, as the dry matter content, buffering capacity, and urease activity can be helpful on the prediction of their responses to the ammoniation.

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

    International Nuclear Information System (INIS)

    Neretnieks, Ivars

    2006-12-01

    could accommodate the same flowrate. The short contact time of the water with the canister allows only a small fraction of the solute in the water react with the copper canister. This strongly limits the rate of corrosion. Furthermore the corrosive attack can be expected to spread out in a semi circle into the copper wall and not be limited only to the width of the fracture in the buffer. These effects together imply that although the rate of localized corrosion is larger than for an intact buffer it still would take hundreds of thousands of years for the highest considered flowrate in this note to penetrate the canister. The release rate of radionuclides from a damaged canister is strongly limited by their rate of diffusion through a hole in the canister. For holes in the canister of up to ten cm in diameter the radionuclide release is limited by the diffusion resistance in the hole. The damages in the buffer causing high flowrates in the deposition hole will not give an increase in nuclide release as long as the hole in the canister is not exceedingly large and provided there is no flow through the canister. It is also suggested that if in an earthquake scenario the canister is sheared but the buffer is still intact prohibiting water flow through the deposition hole, the diffusion resistance for nuclides in the remaining buffer strongly limits the rate of release of nuclides

  14. The thermodynamic-buffer enzymes.

    Science.gov (United States)

    Stucki, J W

    1980-08-01

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

  15. The effect of buffered calcium diffusion on neurotransmitter release

    Science.gov (United States)

    Ponce Dawson, Silvina; Uchitel, Osvaldo D.

    2002-08-01

    Calcium plays a major role in inter-neuron communication. It has recently been observed that the scaling relationship between extracellular calcium concentration and postsynaptic response is different depending on the channel through which calcium enters the presynaptic neuron. Experiments suggest that the two types of calcium channels probed in this regard are at different mean distances from the neurotransmitter-containing vesicles. In this work we investigate whether the effect of calcium buffers along the path from the channel to the vesicle sensor can be responsible for the differences observed. Our results show that buffers cannot account for this change. This study also allows us to probe the limitations of the rapid buffering approximation in the presence of strong and localized sources.

  16. Buffer storage blocks made in the CAMAC standard

    International Nuclear Information System (INIS)

    Zamyatin, N.I.; Smolin, D.A.

    1976-01-01

    Buffer storage units in the ''CAMAC'' standard have been elaborated. Specifications, principles of construction and circuit realization of main components of two memory units are presented. The accumulator of one memory unit employs 32 MOS memory matrices and has an information capacity of 512 bit. The accumulator of the other unit with a capacity of 512 bit employs 16 integrated circuits. Information recording and readout is performed by 16-digit words with a binary code. The memory units described ensure quick acquisition of information, its storage and delivery to the computer. Minimum recording time of one 16-digit word is 0.4 musec

  17. Buffer layer enhanced stability of sodium-ion storage

    Science.gov (United States)

    Wang, Xusheng; Yang, Zhanhai; Wang, Chao; Chen, Dong; Li, Rui; Zhang, Xinxiang; Chen, Jitao; Xue, Mianqi

    2017-11-01

    Se-Se buffer layers are introduced into tin sequences as SnSe2 single crystal to enhance the cycling stability for long-term sodium-ion storage by blazing a trail of self-defence strategy to structural pulverization especially at high current density. Specifically, under half-cell test, the SnSe2 electrodes could yield a high discharge capacity of 345 mAh g-1 after 300 cycles at 1 A g-1 and a high discharge capacity of 300 mAh g-1 after 2100 cycles at 5 A g-1 with stable coulombic efficiency and no capacity fading. Even with the ultrafast sodium-ion storage at 10 A g-1, the cycling stability still makes a positive response and a high discharge capacity of 221 mAh g-1 is demonstrated after 2700 cycles without capacity fading. The full-cell test for the SnSe2 electrodes also demonstrates the superior cycling stability. The flexible and tough Se-Se buffer layers are favourable to accommodate the sodium-ion intercalation process, and the autogenous Na2Se layers could confine the structural pulverization of further sodiated tin sequences by the slip along the Na2Se-NaxSn interfaces.

  18. How Might New Neurons Buffer Against Stress?

    Science.gov (United States)

    ... Institute Announcements (104 items) How Might New Neurons Buffer Against Stress? Clues Emerging from Studies in New ... better understand how having new neurons appears to buffer against stress effects on behavior, the NIMH researchers ...

  19. Buffer Zone Requirements for Soil Fumigant Applications

    Science.gov (United States)

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

  20. Deceleration buffer for hydraulic linear motion drive

    International Nuclear Information System (INIS)

    Jamrus, K.J.

    1982-01-01

    Braking of the motion of a fluid-actuated drive is provided by a buffer arrangement which is normally sealed to prevent vaporization of the fluid in a buffer cylinder and which isolates the drive piston rings from braking pressures

  1. Doped LZO buffer layers for laminated conductors

    Science.gov (United States)

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

    2010-03-23

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

  2. RESEARCH NEEDS IN RIPARIAN BUFFER RESTORATION

    Science.gov (United States)

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

  3. Extrusion analysis of buffer using diffusion model

    International Nuclear Information System (INIS)

    Sugino, H.; Kanno, T.

    1999-11-01

    The buffer material that will be buried as a component of the engineered barriers system swells when saturation by groundwater. As a result of this swelling, buffer material may penetrate into the peripheral rock zone surrounding the buffer through open fractures. If sustained for extremely in long-period of time. The buffer material extrusion could lead to reduction of buffer density, which may in turn degrade the assumed performance assessment properties (e.g., permeability, diffusion coefficient). JNC has been conducted the study of bentonite extrusion into fractures of rock mass as a part of high level waste research. In 1997, JNC has reported the test results concerning buffer material extrusion and buffer material erosion. These tests have been done using test facilities in Geological Isolation Basic Research Facility. After 1997, JNC also conducted analytical study of buffer material extrusion. This report describes the analysis results of this study which are reflected to the H12 report. In this analysis, the diffusion coefficient was derived as a function of the swelling pressure and the viscosity resistance of the buffer materials. Thus, the reduction in density of buffer materials after emplacement in saturated rock was assessed. The assessment was made assuming parallel-plate radial fractures initially filled by water only. Because fractures in natural rock masses inevitably have mineral inclusions inside of them and fractures orientation leads to fractures intersecting other fractures, this analysis gives significantly conservative conditions with respect to long-term extrusion of buffer and possible decrease in buffer density. (author)

  4. Fluoroalcohols as novel buffer components for basic buffer solutions for liquid chromatography electrospray ionization mass spectrometry: retention mechanisms.

    Science.gov (United States)

    Kipper, Karin; Herodes, Koit; Leito, Ivo

    2011-11-11

    Two fluoroalcohols--1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol (HFTB)--were evaluated as volatile buffer acids in basic mobile phases for LC-ESI-MS determination of acidic and basic compounds. HFIP and HFTB as acidic buffer components offer interesting possibilities to adjust retention behavior of different analytes and expand the currently rather limited range of ESI-compatible buffer systems for basic mobile phases. Comparing with commonly used basic buffer components the fluoroalcohols did not suppress the ionization of the analytes, for several analytes ionization enhancement was observed. RP chromatographic retention mechanisms were evaluated and compared to traditional buffer system. All trends in retention of the acidic and basic analytes can be interpreted by the following model: the neutral fluoroalcohols are quite strongly retained by the stationary phase whereas their anions are less retained, thus their amount on the stationary phase is dependent on mobile phase pH; the anions of the fluoroalcohols form ion pairs in the mobile phase with the basic analytes; the fluoroalcohols on the stationary phase surface compete with acidic analytes thereby hindering their retention; the fluoroalcohols on the stationary phase bind basic analytes thereby favoring their retention. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2009-06-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

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

    OpenAIRE

    Simmons, Phil

    1988-01-01

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

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

    International Nuclear Information System (INIS)

    Suryantoro; Arimuladi, S.P.; Sastrowardoyo, P.B.

    1998-01-01

    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)

  9. Internal acid buffering in San Joaquin Valley fog drops and its influence on aerosol processing

    Science.gov (United States)

    Collett, Jeffrey L.; Hoag, Katherine J.; Rao, Xin; Pandis, Spyros N.

    Although several chemical pathways exist for S(IV) oxidation in fogs and clouds, many are self-limiting: as sulfuric acid is produced and the drop pH declines, the rates of these pathways also decline. Some of the acid that is produced can be buffered by uptake of gaseous ammonia. Additional internal buffering can result from protonation of weak and strong bases present in solution. Acid titrations of high pH fog samples (median pH=6.49) collected in California's San Joaquin Valley reveal the presence of considerable internal acid buffering. In samples collected at a rural location, the observed internal buffering could be nearly accounted for based on concentrations of ammonia and bicarbonate present in solution. In samples collected in the cities of Fresno and Bakersfield, however, significant additional, unexplained buffering was present over a pH range extending from approximately four to seven. The additional buffering was found to be associated with dissolved compounds in the fogwater. It could not be accounted for by measured concentrations of low molecular weight ( C1- C3) carboxylic acids, S(IV), phosphate, or nitrophenols. The amount of unexplained buffering in individual fog samples was found to correlate strongly with the sum of sample acetate and formate concentrations, suggesting that unmeasured organic species may be important contributors. Simulation of a Bakersfield fog episode with and without the additional, unexplained buffering revealed a significant impact on the fog chemistry. When the additional buffering was included, the simulated fog pH remained 0.3-0.7 pH units higher and the amount of sulfate present after the fog evaporated was increased by 50%. Including the additional buffering in the model simulation did not affect fogwater nitrate concentrations and was found to slightly decrease ammonium concentrations. The magnitude of the buffering effect on aqueous sulfate production is sensitive to the amount of ozone present to oxidize S

  10. Agroforestry buffers for nonpoint source pollution reductions from agricultural watersheds.

    Science.gov (United States)

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

    2011-01-01

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

  11. Buffered Electrochemical Polishing of Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tian, Hui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States); Corcoran, Sean [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2011-03-01

    The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop.' In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature (? 120 °C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

  12. Anolyte recycling enhanced bioelectricity generation of the buffer-free single-chamber air-cathode microbial fuel cell.

    Science.gov (United States)

    Ren, Yueping; Chen, Jinli; Shi, Yugang; Li, Xiufen; Yang, Na; Wang, Xinhua

    2017-11-01

    Anolyte acidification is an inevitable restriction for the bioelectricity generation of buffer-free microbial fuel cells (MFCs). In this work, acidification of the buffer-free KCl anolyte has been thoroughly eliminated through anolyte recycling. The accumulated HCO 3 - concentration in the recycled KCl anolyte was above 50mM, which played as natural buffer and elevated the anolyte pH to above 8. The maximum power density (P max ) increased from 322.9mWm -2 to 527.2mWm -2 , which is comparable with the phosphate buffered MFC. Besides Geobacter genus, the gradually increased anolyte pH and conductivity induced the growing of electrochemically active Geoalkalibacter genus, in the anode biofilm. Anolyte recycling is a feasible strategy to strengthen the self-buffering capacity of buffer-free MFCs, thoroughly eliminate the anolyte acidification and prominently enhance the electric power. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Modelling of buffer material behaviour

    International Nuclear Information System (INIS)

    Boergesson, L.

    1988-12-01

    Some material models of smectite rich buffer material suited for nuclear waste isolation are accounted for in the report. The application of these models in finite element calculations of some scenarios and performance are also shown. The rock shear scenario has been closely studied with comparisons between calculated and measured results. Sensitivity analyses of the effect of changing the density of the clay and the rate of shear have been performed as well as one calculation using a hollow steel cylinder. Material models and finite element calculations of canister settlement, thermomechanical effects and swelling are also accounted for. The report shows the present state of the work to establish material models and calculation tools which can be used at the final design of the repository. (31 illustrations)

  14. 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.

  15. Melatonin: Buffering the Immune System

    Science.gov (United States)

    Carrillo-Vico, Antonio; Lardone, Patricia J.; Álvarez-Sánchez, Nuria; Rodríguez-Rodríguez, Ana; Guerrero, Juan M.

    2013-01-01

    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. PMID:23609496

  16. Stacked Switched Capacitor Energy Buffer Architecture

    OpenAIRE

    Chen, Minjie; Perreault, David J.; Afridi, Khurram

    2012-01-01

    Electrolytic capacitors are often used for energy buffering applications, including buffering between single-phase ac and dc. While these capacitors have high energy density compared to film and ceramic capacitors, their life is limited. This paper presents a stacked switched capacitor (SSC) energy buffer architecture and some of its topological embodiments, which when used with longer life film capacitors overcome this limitation while achieving effective energy densities comparable to elect...

  17. Signature-based store checking buffer

    Science.gov (United States)

    Sridharan, Vilas; Gurumurthi, Sudhanva

    2015-06-02

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

  18. Systemic Risk, Bank's Capital Buffer, and Leverage

    OpenAIRE

    Wibowo, Buddi

    2017-01-01

    This paper measures individual bank's impact on banking systemic risk and examines the effect of individual bank's capital buffer and leverage to bank's systemic risk impact in Indonesia during 2010-2014. Using Merton's distance-to-default to measure systemic risk, the study shows a significant negative relationship between bank's capital buffer and systemic risk. High capital buffer tends to lowering bank's impact on systemic risk. Bank's leverage level also influences its contribution to sy...

  19. Revelle revisited: Buffer factors that quantify the response of ocean chemistry to changes in DIC and alkalinity

    Science.gov (United States)

    Egleston, Eric S.; Sabine, Christopher L.; Morel, FrançOis M. M.

    2010-03-01

    We derive explicit expressions of the Revelle factor and several other buffer factors of interest to climate change scientists and those studying ocean acidification. These buffer factors quantify the sensitivity of CO2 and H+ concentrations ([CO2] and [H+]) and CaCO3 saturation (Ω) to changes in dissolved inorganic carbon concentration (DIC) and alkalinity (Alk). The explicit expressions of these buffer factors provide a convenient means to compare the degree of buffering of [CO2], [H+], and Ω in different regions of the oceans and at different times in the future and to gain insight into the buffering mechanisms. All six buffer factors have roughly similar values, and all reach an absolute minimum when DIC = Alk (pH ˜ 7.5). Surface maps of the buffer factors generally show stronger buffering capacity in the subtropical gyres relative to the polar regions. As the dissolution of anthropogenic CO2 increases the DIC of surface seawater over the next century, all the buffer factors will decrease, resulting in a much greater sensitivity to local variations in DIC and Alk. For example, diurnal and seasonal variations in pH and Ω caused by photosynthesis and respiration will be greatly amplified. Buffer factors provide convenient means to quantify the effect that changes in DIC and Alk have on seawater chemistry. They should also help illuminate the role that various physical and biological processes have in determining the oceanic response to an increase in atmospheric CO2.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  1. Temperature buffer test. Dismantling operation

    International Nuclear Information System (INIS)

    Aakesson, Mattias

    2010-12-01

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

  2. 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

  3. Success and failure with phthalate buffers in capillary zone electrophoresis.

    Science.gov (United States)

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

    2001-04-01

    Phthalate buffers are currently used in capillary electrophoresis as robust electrolyte systems for indirect detection. This contribution demonstrates that these buffers show regularly not only successful regions of mobilities of analytes (sample window) but also regions of failure where the migration of analytes is strongly deteriorated due to the presence of a system zone. System zones in phthalate buffers may be easily detected by UV detection and manifest themselves as peaks or dips. Peak shape diagrams are advantageously used for the prediction of the migration behavior of system zones in phthalate background electrolyte (BGE) systems at various pH. It is shown that the mobility of the system zone varies strongly with pH, is practically zero at pH values below 4 and above 7, and shows a maximum at pH 5. Thus, the system peak may coincide either with the peaks of various analytes or with the electroosmotic flow (EOF) peak. Experiments are given showing the effects of such coincidences as, e.g., zigzag detection patterns, double EOF peaks, and/or unusually broad peaks/dips. The message of this contribution is to show how to understand the electrophoretic properties of phthalate BGEs that, regardless of possible failure regions, may be successfully used in the analytical practice of capillary zone electrophoresis (CZE).

  4. Oxidation of Good's buffers by hydrogen peroxide.

    Science.gov (United States)

    Zhao, Guanghua; Chasteen, N Dennis

    2006-02-15

    Good's zwitterionic buffers are widely used in biological and biochemical research in which hydrogen peroxide is a solution component. This study was undertaken to determine whether Good's buffers exhibit reactivity toward H(2)O(2). It is found that H(2)O(2) oxidizes both morpholine ring-containing buffers (e.g., Mops, Mes) and piperazine ring-containing zwitterionic buffers (e.g., Pipes, Hepes, and Epps) to produce their corresponding N-oxide forms. The percentage of oxidized buffer increases as the concentration of H(2)O(2) increases. However, the rate of oxidation is relatively slow. For example, no oxidized Mops was detected 2h after adding 0.1M H(2)O(2) to 0.1M Mops (pH 7.0), and only 5.7% was oxidized after 24h exposure to H(2)O(2). Thus, although all of these buffers can be oxidized by H(2)O(2), their slow reaction does not significantly perturb levels of H(2)O(2) in the time frame and at the concentrations of most biochemical studies. Therefore, the previously reported rapid loss of H(2)O(2) produced from the ferroxidase reaction of ferritin is unlikely due to reaction of H(2)O(2) with buffer, a conclusion supported by the fact that H(2)O(2) is also lost rapidly when the solution pH of the ferroxidase reaction is controlled by a pH stat apparatus in the absence of buffer.

  5. Buffer Management Simulation in ATM Networks

    Science.gov (United States)

    Yaprak, E.; Xiao, Y.; Chronopoulos, A.; Chow, E.; Anneberg, L.

    1998-01-01

    This paper presents a simulation of a new dynamic buffer allocation management scheme in ATM networks. To achieve this objective, an algorithm that detects congestion and updates the dynamic buffer allocation scheme was developed for the OPNET simulation package via the creation of a new ATM module.

  6. Evidence of a Strong Correlation Between Oxygen Nonstoichiometry (d) and Oxygen Uptake Capacities of La{sub 1-x}Sr{sub x}Co{sub 0.2}Fe{sub 0.8}O{sub 3-d} oxides (0.1 < Sr{sub x} < 0.4)

    Energy Technology Data Exchange (ETDEWEB)

    Magnone, Edoardo; Kim, Jung Ryoel; Park, Jung Hoon [Dongguk Univ., Seoul (Korea, Republic of); Park, Seongkyu [KOFIRST R and D Center, Icheon (Korea, Republic of)

    2014-07-15

    The communication provided clear evidence of a strong correlation between the nonstoichiometry oxygen content (d) or oxygen content (3-d) and the maximum oxygen uptake capacity of La{sub 1-x}Sr{sub x}Co{sub 0.2}Fe{sub 0.8}O{sub 3-d} oxides (0.1 < x < 0.4). The results may be considered as a provisional basis for further research, allowing the prediction of the oxygen uptake capacities at low temperature by easy determination of oxygen contents. Recently, there has been a growing interest in utilizing nonstoichiometric La{sub 1-x}Sr{sub x}Co{sub 1-y}Fe{sub y}O{sub 3-d} perovskite-type oxide as sorbents for high-temperature production of oxygen-enriched carbon dioxide stream. During the past decades, many studies have been conducted on these solid solutions, and in order to achieve higher oxygen uptake capacities, the La{sup 3+} lanthanide was substituted by bivalent Sr{sup 2+} alkaline-earth ions to decrease the ionicity of the Ln.O bond which could result in an increased number of hole.

  7. In situ buffer material test, (1)

    International Nuclear Information System (INIS)

    Kumata, Masahiro; Muraoka, Susumu; Shimooka, Kenji; Araki, Kunio; Okamoto, Masamichi.

    1987-10-01

    Buffer materials would be placed between a package and wall rock in a disposal pit in a deep geological formation in the concept for geological disposal of high level radioactive wastes. A bentonite powder produced in our country was compacted in a test hole in-situ into 1.27 kg/cm 3 at 380 m below surface and heated with a electric heater about 882 hours. The value of obtained thermal conductivity of the buffer material was slightly larger than those of the laboratory data. The results of the measurements of the moisture of the buffer material using a Neutron Moisture Meter revealed that the buffer material was dried during the heating and groundwater penetrated from fractures of the wall rock into the buffer material after heating was stopped. (author)

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

    OpenAIRE

    Moir, Brian; Piggott, Roley R.

    1991-01-01

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

  9. A methodology for determining and controlling the buffers before floating bottlenecks in heavy machinery production

    Directory of Open Access Journals (Sweden)

    R. Lenort

    2013-07-01

    Full Text Available Heavy machinery industry is characterized by a number of specific features that cause significant variations in the processing time of products in the individual workplaces and frequent occurrence of floating bottlenecks, which change their positions. Depending on the product range being processed, a given workplace is the bottleneck only for some period of time. When the bottleneck moves to another workplace, it leads to unnecessary loss of capacity of the floating bottleneck. To maximize the utilization, it is necessary to protect those bottlenecks by creating special buffers. The objective of this article is to design a methodology used for the determination and control of buffers that are going to protect the floating bottlenecks from operating capacity losses caused by transfer of the constrain to another workplace. These buffers are referred to as „power buffers“. The designed methodology has been verified in the process of forged pieces machining.

  10. Plant trait diversity buffers variability in denitrification potential over changes in season and soil conditions.

    Directory of Open Access Journals (Sweden)

    Bonnie M McGill

    Full Text Available BACKGROUND: Denitrification is an important ecosystem service that removes nitrogen (N from N-polluted watersheds, buffering soil, stream, and river water quality from excess N by returning N to the atmosphere before it reaches lakes or oceans and leads to eutrophication. The denitrification enzyme activity (DEA assay is widely used for measuring denitrification potential. Because DEA is a function of enzyme levels in soils, most ecologists studying denitrification have assumed that DEA is less sensitive to ambient levels of nitrate (NO(3(- and soil carbon and thus, less variable over time than field measurements. In addition, plant diversity has been shown to have strong effects on microbial communities and belowground processes and could potentially alter the functional capacity of denitrifiers. Here, we examined three questions: (1 Does DEA vary through the growing season? (2 If so, can we predict DEA variability with environmental variables? (3 Does plant functional diversity affect DEA variability? METHODOLOGY/PRINCIPAL FINDINGS: The study site is a restored wetland in North Carolina, US with native wetland herbs planted in monocultures or mixes of four or eight species. We found that denitrification potentials for soils collected in July 2006 were significantly greater than for soils collected in May and late August 2006 (p<0.0001. Similarly, microbial biomass standardized DEA rates were significantly greater in July than May and August (p<0.0001. Of the soil variables measured--soil moisture, organic matter, total inorganic nitrogen, and microbial biomass--none consistently explained the pattern observed in DEA through time. There was no significant relationship between DEA and plant species richness or functional diversity. However, the seasonal variance in microbial biomass standardized DEA rates was significantly inversely related to plant species functional diversity (p<0.01. CONCLUSIONS/SIGNIFICANCE: These findings suggest that

  11. Carrying Capacity

    DEFF Research Database (Denmark)

    Schroll, Henning; Andersen, Jan; Kjærgård, Bente

    2012-01-01

    A spatial planning act was introduced inIndonesia 1992 and renewed in 2008. It emphasised the planning role of decentralised authorities. The spatial planning act covers both spatial and environmental issues. It defines the concept of carrying capacity and includes definitions of supportive....../cities. Four different sectors (water, food production, waste, and forests) were selected as core areas for decentralised spatial planning. Indicators for SCC and ACC were identified and assessed with regard to relevance and quantifiability. For each of the indicators selected, a legal threshold or guiding...... was introduced inIndonesia 1992 and renewed in 2008. It emphasised the planning role of decentralised authorities. The spatial planning act covers both spatial and environmental issues. It defines the concept of carrying capacity and includes definitions of supportive carrying capacity (SCC) and assimilative...

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  13. 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

  14. Effects of humic acid-based buffer + cation on chemical characteristics of saline soils and maize growth

    Directory of Open Access Journals (Sweden)

    W. Mindari

    2014-10-01

    Full Text Available Humic acid is believed to maintain the stability of the soil reaction, adsorption / fixation / chelate of cation, thereby increasing the availability of water and plant nutrients. On the other hand, the dynamics of saline soil cation is strongly influenced by the change of seasons that disrupt water and plant nutrients uptake. This experiment was aimed to examine the characteristics of the humic acid from compost, coal, and peat and its function in the adsorption of K+ and NH4+ cations, thus increasing the availability of nutrients and of maize growth. Eighteen treatments consisted of three humic acid sources (compost, peat and coal, two cation additives (K+ and NH4+, and three doses of humic acid-based buffer (10, 20, and 30 g / 3kg, were arranged in a factorial completely randomized with three replicates. The treatments were evaluated against changes in pH, electric conductivity (EC, cation exchange capacity (CEC, chlorophyll content, plant dry weight and plant height. The results showed that the addition of K+ and NH4+ affected pH, CEC, K+, NH4+, and water content of the buffer. Application of humic acid-based buffer significantly decreased soil pH from > 7 to about 6.3, decreased soil EC to 0.9 mS / cm, and increased exchangeable Na from 0.40 to 0.56 me / 100g soil, Ca from 15.57 to 20.21 me/100 g soil, Mg from 1.76 to 6.52 me/100 g soil, and K from 0.05-0.51 me / 100g soil. Plant growth (plant height, chlorophyll content, leaf area, and stem weight at 35 days after planting increased with increasing dose of humic acid. The dose of 2.0g peat humic acid + NH4+ / 3 kg of soil or 30g peat humic acid + K+ / 3 kg of oil gave the best results of maize growth.

  15. Basic characteristics data base of buffer material

    International Nuclear Information System (INIS)

    Kikuchi, Hirohito; Tanai, Kenji

    2004-02-01

    For the buffer material of geological disposal of High-Level radioactive Waste (HLW) in Japan, it is expected to maintain its low water permeability, thermal conductivity, self-sealing, radionuclide sorption and retardation, chemical buffering, overpack support and stress buffering properties over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above functions. Among the kinds of natural clay, bentonite when compacted is superior because (1) it has exceptionally low water permeability and properties to control the movement of water in buffer, (2) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (3) it has ability to exchange cations and to adsorb cationic radioelements. Japan Nuclear Cycle Development Institute has extended the basic characteristics data of buffer material as one of the base information required for safe regulation of a country and HLW disposal project. This report presents the basic characteristics data of the buffer material which JNC acquired by December, 2003 was collected as a collection of data. (author)

  16. Station Capacity

    DEFF Research Database (Denmark)

    Landex, Alex

    2011-01-01

    the probability of conflicts and the minimum headway times into account. The last method analyzes how optimal platform tracks are used by examining the arrival and departure pattern of the trains. The developed methods can either be used separately to analyze specific characteristics of the capacity of a station...

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

    Science.gov (United States)

    Michalke, D; Kolb, S; Welsch, T

    2001-05-04

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

  18. Professional commitment: Does it buffer or intensify job demands?

    Science.gov (United States)

    Nesje, Kjersti

    2017-04-01

    The purpose of this study is to investigate whether professional commitment can be seen as a moderator in the relationship between job demands and emotional exhaustion among Norwegian nurses. Inspired by the job demands-resources model, this study explores whether having a strong commitment to the nursing profession can be seen as a resource that buffers the effect of job demands on emotional exhaustion or, conversely, intensifies the impact of job demands. A survey that comprised Norwegian nurses who had graduated three years previously (N = 388) was conducted. Multiple regression was performed to test the hypothesis. The results provide support to a buffering effect; thus, individuals with a higher degree of professional commitment conveyed a weaker association between job demands and emotional exhaustion compared with nurses with a lower degree of commitment. Developing a better understanding of the potential buffering effect of professional commitment is of great interest. The present study is the first to utilize professional commitment as a resource within the job demands-resources framework. © 2017 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  19. Symbiosis revisited: phosphorus and acid buffering stimulate N2 fixation but not Sphagnum growth

    Science.gov (United States)

    van den Elzen, Eva; Kox, Martine A. R.; Harpenslager, Sarah F.; Hensgens, Geert; Fritz, Christian; Jetten, Mike S. M.; Ettwig, Katharina F.; Lamers, Leon P. M.

    2017-03-01

    In pristine Sphagnum-dominated peatlands, (di)nitrogen (N2) fixing (diazotrophic) microbial communities associated with Sphagnum mosses contribute substantially to the total nitrogen input, increasing carbon sequestration. The rates of symbiotic nitrogen fixation reported for Sphagnum peatlands, are, however, highly variable, and experimental work on regulating factors that can mechanistically explain this variation is largely lacking. For two common fen species (Sphagnum palustre and S. squarrosum) from a high nitrogen deposition area (25 kg N ha-1 yr-1), we found that diazotrophic activity (as measured by 15 - 15N2 labeling) was still present at a rate of 40 nmol N gDW-1 h-1. This was surprising, given that nitrogen fixation is a costly process. We tested the effects of phosphorus availability and buffering capacity by bicarbonate-rich water, mimicking a field situation in fens with stronger groundwater or surface water influence, as potential regulators of nitrogen fixation rates and Sphagnum performance. We expected that the addition of phosphorus, being a limiting nutrient, would stimulate both diazotrophic activity and Sphagnum growth. We indeed found that nitrogen fixation rates were doubled. Plant performance, in contrast, did not increase. Raised bicarbonate levels also enhanced nitrogen fixation, but had a strong negative impact on Sphagnum performance. These results explain the higher nitrogen fixation rates reported for minerotrophic and more nutrient-rich peatlands. In addition, nitrogen fixation was found to strongly depend on light, with rates 10 times higher in light conditions suggesting high reliance on phototrophic organisms for carbon. The contrasting effects of phosphorus and bicarbonate on Sphagnum spp. and their diazotrophic communities reveal strong differences in the optimal niche for both partners with respect to conditions and resources. This suggests a trade-off for the symbiosis of nitrogen fixing microorganisms with their Sphagnum

  20. 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....

  1. Calculating Buffer Zones: A Guide for Applicators

    Science.gov (United States)

    Buffer zones provide distance between the application block (i.e., edge of the treated field) and bystanders, in order to control pesticide exposure risk from soil fumigants. Distance requirements may be reduced by credits such as tarps.

  2. Buffer Strips for Riparian Zone Management

    National Research Council Canada - National Science Library

    1991-01-01

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

  3. 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...... scenarios are developed and visualized using maps, photography and artwork. The potential effects on the landscape N-cycle are discussed. Nitrogen removal by biomass production using forage or energy grasses, short rotation coppice willow/poplar or short rotation forestry with other tree species in buffers...

  4. Exerting Capacity.

    Science.gov (United States)

    Leger, J Michael; Phillips, Carolyn A

    2017-05-01

    Patient safety has been at the forefront of nursing research since the release of the Institute of Medicine's report estimating the number of preventable adverse events in hospital settings; yet no research to date has incorporated the perspectives of bedside nurses using classical grounded theory (CGT) methodology. This CGT study explored the perceptions of bedside registered nurses regarding patient safety in adult acute care hospitals. Data analysis used three techniques unique to CGT-the constant comparative method, coding, and memoing-to explore the values, realities, and beliefs of bedside nurses about patient safety. The analysis resulted in a substantive theory, Exerting Capacity, which explained how bedside nurses balance the demands of keeping their patients safe. Exerting Capacity has implications for health care organization leaders, nursing leaders, and bedside nurses; it also has indications for future research into the concept of patient safety.

  5. Effects of Anodic Buffer Layer in Top-Illuminated Organic Solar Cell with Silver Electrodes

    Directory of Open Access Journals (Sweden)

    Tien-Lung Chiu

    2013-01-01

    Full Text Available An efficient ITO-free top-illuminated organic photovoltaic (TOPV based on small molecular planar heterojunction was achieved by spinning a buffer layer of poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS, on the Ag-AgOx anode. The PEDOT:PSS thin film separates the active layer far from the Ag anode to prevent metal quenching and redistributes the strong internal optical field toward dissociated interface. The thickness and morphology of this anodic buffer layer are the key factors in determining device performances. The uniform buffer layer contributes a large short-circuit current and open-circuit voltage, benefiting the final power conversion efficiency (PCE. The TOPV device with an optimal PEDOT:PSS thickness of about 30 nm on Ag-AgOx anode exhibits the maximum PCE of 1.49%. It appreciates a 1.37-fold enhancement in PCE over that of TOPV device without buffer layer.

  6. Lucas Heights buffer zone: plan of management

    International Nuclear Information System (INIS)

    1986-01-01

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

  7. Erosion of buffer caused by groundwater leakages

    International Nuclear Information System (INIS)

    Autio, J.; Hanana, K.; Punkkinen, O.; Koskinen, K.; Olin, M.

    2010-01-01

    Document available in extended abstract form only. In the Finnish HLW disposal concept the most important properties of the bentonite clay being considered for these isolation purposes are its thermal behaviour, low hydraulic conductivity, diffusion limited transport, rheology, plasticity, sufficient swelling potential, and exchange capacity. All of these properties depend critically on bentonite density; therefore, any potential mass loss or redistribution events must be well characterized. One such event or process is the erosion of bentonite by flowing groundwater and the groundwater flowing in newly formed channels, in special. Mechanical erosion during the operational phase, due to high groundwater pressure gradients in open excavations, has been identified as a critical issue in TKS-2006 and SR-Can. This work addresses the mechanical erosion of bentonite by fluid shear. In order for buffer erosion to occur three processes must take place: detachment, entrainment, and transport. These processes are followed by the settling of the material and redistribution of buffer mass. Erosion begins with the detachment of a particle from surrounding material, which requires the application of shear forces greater than the attractive force between the particle and parent structure. Entrainment is the process by which the eroding medium lifts the detached particle into the flow. The most important aspect in entrainment is transfer of fluid's inertial forces via surface friction to particles' inertial forces, which, in turn, must overcome the frictional resistance between the particle and its surroundings. Factors influencing frictional resistance include gravity, particle mass, saturation degree of parent structure, composition of water present in parent structure, particle size, and surface roughness. Recent erosion tests, whereby water flow was directed over compacted bentonite blocks or through a system of bentonite pellets, have indicated that bentonite erodes

  8. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  9. Buffer regulation of calcium puff sequences.

    Science.gov (United States)

    Fraiman, Daniel; Dawson, Silvina Ponce

    2014-02-01

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

  10. 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.

  11. Thermal buffering performance of composite phase change materials applied in low-temperature protective garments

    Science.gov (United States)

    Yang, Kai; Jiao, Mingli; Yu, Yuanyuan; Zhu, Xueying; Liu, Rangtong; Cao, Jian

    2017-07-01

    Phase change material (PCM) is increasingly being applied in the manufacturing of functional thermo-regulated textiles and garments. This paper investigated the thermal buffering performance of different composite PCMs which are suitable for the application in functional low-temperature protective garments. First, according to the criteria selecting PCM for functional textiles/garments, three kinds of pure PCM were selected as samples, which were n-hexadecane, n-octadecane and n-eicosane. To get the adjustable phase change temperature range and higher phase change enthalpy, three kinds of composite PCM were prepared using the above pure PCM. To evaluate the thermal buffering performance of different composite PCM samples, the simulated low-temperature experiments were performed in the climate chamber, and the skin temperature variation curves in three different low temperature conditions were obtained. Finally composite PCM samples’ thermal buffering time, thermal buffering capacity and thermal buffering efficiency were calculated. Results show that the comprehensive thermal buffering performance of n-octadecane and n-eicosane composite PCM is the best.

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

    Science.gov (United States)

    Jaynes, D B; Isenhart, T M

    2014-03-01

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

  13. BUFCALC: A Program for the Calculation of Buffers of Specified pH, Ionic Strength, and Buffer Capacity.

    Science.gov (United States)

    Lambert, William J.

    1990-01-01

    Reviewed is a computer software package for IBM personal computers. The theoretical background and functions including several examples are discussed. The algorithm used in computation by the program is given. (CW)

  14. Contributions of separate reactions to the acid-base buffering of soils in brook floodplains (Central Forest State Reserve)

    Science.gov (United States)

    Sokolova, T. A.; Tolpeshta, I. I.; Rusakova, E. S.

    2016-04-01

    The acid-base buffering of gleyic gray-humus soils developed in brook floodplains and undisturbed southern-taiga landscapes has been characterized by the continuous potentiometric titration of soil water suspensions. During the interaction with an acid, the major amount of protons (>80%) is consumed for the displacement of exchangeable bases and the dissolution of Ca oxalates. In the O and AY horizons, Mn compounds make the major contribution (2-15%) to the acid buffering. The buffer reactions with the participation of Al compounds make up from 0.5 to 1-2% of the total buffering capacity, and the protonation of the surface OH groups of kaolinite consumes 2-3% of the total buffering capacity. The deprotonation of OH groups on the surface of Fe hydroxides (9-43%), the deprotonation of OH groups on the surface of illite crystals (3-19%), and the dissolution of unidentified aluminosilicates (9-14%) are the most significant buffer reactions whose contributions have been quantified during the interaction with a base. The contribution of the deprotonation of OH groups on the surface of kaolinite particles is lower (1-5%) because of the small specific surface area of this mineral, and that of the dissolution of Fe compounds is insignificant. In the AY horizon, the acid and base buffering of soil in the rhizosphere is higher than beyond the rhizosphere because of the higher contents of organic matter and nonsilicate Fe and Al compounds.

  15. Peak shapes of acids and bases under overloaded conditions in reversed-phase liquid chromatography, with weakly buffered mobile phases of various pH: a thermodynamic interpretation.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2009-01-02

    species adsorbs strongly on a first type of sites that have a high density while the ionic species adsorb preferentially on a second type of sites that have a very low density. The evolution of the peak shape when the pHWS changes from acidic to basic is well explained by the weak buffer capacity of the mobile phase used compared to the concentration of the eluted compounds.

  16. Assessment of polyelectrolyte coating stability under dynamic buffer conditions in CE.

    Science.gov (United States)

    Swords, Kyleen E; Bartline, Peter B; Roguski, Katherine M; Bashaw, Sarah A; Frederick, Kimberley A

    2011-09-01

    Dynamic buffer conditions are present in many electrophoretically driven separations. Polyelectrolyte multilayer coatings have been employed in CE because of their chemical and physical stability as well as their ease of application. The goal of this study is to measure the effect of dynamic changes in buffer pH on flow using a real-time method for measuring EOF. Polyelectrolyte multilayers (PEMs) were composed of pairs of strong or completely ionized polyelectrolytes including poly(diallyldimethylammonium) chloride and poly(styrene sulfonate) and weak or ionizable polyelectrolytes including poly(allylamine) and poly(methacrylic acid). Polyelectrolyte multilayers of varying thicknesses (3, 4, 7, 8, 15, or 16 layers) were also studied. While the magnitude of the EOF was monitored every 2 s, the buffer pH was exchanged from a relatively basic pH (7.1) to increasingly acidic pHs (6.6, 6.1, 5.5, and 5.1). Strong polyelectrolytes responded minimally to changes in buffer pH (10%) and sometimes irreversible changes were measured with weak polyelectrolytes. Thicker coatings resulted in a similar magnitude of response but were more likely to degrade in response to buffer pH changes. The most stable coatings were formed from thinner layers of strong polyelectrolytes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Capacity Building

    International Nuclear Information System (INIS)

    Molloy, Brian; Mallick, Shahid

    2014-01-01

    Outcomes & Recommendations: • Significant increase needed in the nuclear workforce both to replace soon-to-retire current generation and to staff large numbers of new units planned • Key message, was the importance of an integrated approach to workforce development. • IAEA and other International Organisations were asked to continue to work on Knowledge Management, Networks and E&T activities • IAEA requested to conduct Global Survey of HR needs – survey initiated but only 50% of operating countries (30% of capacity) took part, so results inconclusive

  18. Static mechanical properties of buffer material

    International Nuclear Information System (INIS)

    Takaji, Kazuhiko; Suzuki, Hideaki

    1999-11-01

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

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

    Science.gov (United States)

    Pearson, Scott F; Giovanini, Jack; Jones, Jay E; Kroll, Andrew J

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Scott F Pearson

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-12-15

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

  2. Linearização de curvas de titulação para determinação da capacidade tamponante da fibra de alimentos em ampla faixa de pH - DOI: 10.4025/actascianimsci.v32i1.5384 Linearization of the titration curves for determination of buffering capacity of feed fiber in a wide pH range - DOI: 10.4025/actascianimsci.v32i1.5384

    Directory of Open Access Journals (Sweden)

    João Ricardo Dittrich

    2009-12-01

    Full Text Available Foi avaliado o método de linearização de curvas de titulação para determinação da capacidade tamponante (CT da fibra em detergente neutro (FDN de 13 alimentos. Foram utilizados dados individuais de dois experimentos, incluindo amostras de aveia branca, aveia preta, azevém, trevo branco e trevo vermelho (ensaio 1, além de amostras de milho, farelo de soja, palha de trigo e cinco misturas destes alimentos (ensaio 2. As titulações foram realizadas do pH inicial até o pH 2,0. A acidez titulável (AT foi medida como a quantidade de HCl necessária (mEq H+ g-1 de FDN para redução do pH inicial da solução até o pH 4,0; 3,0 e 2,0, e a medida taxa linear de tamponamento (TLT foi obtida como inverso da inclinação da regressão linear entre a medida linearizada do pH, calculada como EXP (1 pH-1, e a adição acumulada de HCl em cada intervalo. A transformação resultou em ajuste satisfatório à regressão linear para todos os materiais estudados, com r2 maior que 0,85 e erro-padrão residual menor que 0,059. Houve correlação positiva entre a AT e a TLT medidas nas diferentes faixas de pH. Diferentemente da AT, o método TLT permite obtenção da CT como taxa linear única, válida em qualquer intervalo de pH de 8,0 ao 2,0.A method for linearization of titration curves and its application to determine the buffering capacity (BC of neutral detergent fiber (NDF from 13 feeds and their mixtures was evaluated. Individual data from 2 essays, including samples of white oat, black oat, ryegrass, red clover and white clover (essay 1, and samples of corn, soybean meal, wheat straw and mixtures of these five feeds (essay 2. Titration was performed just to the pH 2.0. The titratable acidity was measured as the amount of HCl needed (mEq g-1 NDF to reduce the initial pH of the solution down to 4.0, 3.0 and 2.0, and the linear buffer (LB measure were determined as the inverse of the slope of the linear regression between linearized pH, calculated

  3. Adsorption mechanism of acids and bases in reversed-phase liquid chromatography in weak buffered mobile phases designed for liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2009-03-06

    The overloaded band profiles of five acido-basic compounds were measured, using weakly buffered mobile phases. Low buffer concentrations were selected to provide a better understanding of the band profiles recorded in LC/MS analyses, which are often carried out at low buffer concentrations. In this work, 10 microL samples of a 50 mM probe solution were injected into C(18)-bonded columns using a series of five buffered mobile phases at (SW)pH between 2 and 12. The retention times and the shapes of the bands were analyzed based on thermodynamic arguments. A new adsorption model that takes into account the simultaneous adsorption of the acidic and the basic species onto the endcapped adsorbent, predicts accurately the complex experimental profiles recorded. The adsorption mechanism of acido-basic compounds onto RPLC phases seems to be consistent with the following microscopic model. No matter whether the acid or the base is the neutral or the basic species, the neutral species adsorbs onto a large number of weak adsorption sites (their saturation capacity is several tens g/L and their equilibrium constant of the order of 0.1 L/g). In contrast, the ionic species adsorbs strongly onto fewer active sites (their saturation capacity is about 1g/L and their equilibrium constant of the order of a few L/g). From a microscopic point of view and in agreement with the adsorption isotherm of the compound measured by frontal analysis (FA) and with the results of Monte-Carlo calculations performed by Schure et al., the first type of adsorption sites are most likely located in between C(18)-bonded chains and the second type of adsorption sites are located deeper in contact with the silica surface. The injected concentration (50 mM) was too low to probe the weakest adsorption sites (saturation capacity of a few hundreds g/L with an equilibrium constant of one hundredth of L/g) that are located at the very interface between the C(18)-bonded layer and the bulk phase.

  4. Capacity and Capacity Utilization in Fishing Industries

    OpenAIRE

    Kirkley, James E; Squires, Dale

    1999-01-01

    Excess capacity of fishing fleets is one of the most pressing problems facing the world's fisheries and the sustainable harvesting of resource stocks. Considerable confusion persists over the definition and measurement of capacity and capacity utilization in fishing. Fishing capacity and capacity utilization, rather than capital (or effort) utilization, provide the appropriate framework. This paper provides both technological-economic and economic definitions of capacity and excess capacity i...

  5. Scientific Applications Performance Evaluation on Burst Buffer

    KAUST Repository

    Markomanolis, George S.

    2017-10-19

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

  6. A buffer overflow detection based on inequalities solution

    International Nuclear Information System (INIS)

    Xu Guoai; Zhang Miao; Yang Yixian

    2007-01-01

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

  7. Improved indexes for targeting placement of buffers of Hortonian runoff

    Science.gov (United States)

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

    2011-01-01

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

  8. Investigations on the passivity of iron in borate and phosphate buffers, pH 8.4

    International Nuclear Information System (INIS)

    Sieber, I.V.; Hildebrand, H.; Virtanen, S.; Schmuki, P.

    2006-01-01

    In the present work surface analytical experiments (XPS and AES) on the passive film on iron formed in borate and phosphate buffers (pH 8.4) have been carried out. In the passive film formed in phosphate buffer a significant amount of phosphates is found in the outer part of the film. Boron species are not significantly incorporated in the passive film formed in borate buffer. The mechanism of the reduction of the passive film depends strongly on the electrolyte composition. In borate buffer, cathodic polarization leads to reductive dissolution of the passive film whereas in phosphate buffer the passive film is converted into metallic iron without dissolution but via laterally inhomogeneously formation of an intermediate Fe(II) phosphate layer

  9. Buffer construction technique using granular bentonite

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  10. Liquid growth hormone: preservatives and buffers

    DEFF Research Database (Denmark)

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

    2004-01-01

    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...... administration. The formulation uses phenol (3 mg/ml) as a preservative (to protect product from microbial degradation or contamination) and histidine as a buffer. Alternative preservatives used in other GH formulations include m-cresol (9 mg/ml) and benzyl alcohol (3-9 mg/ml). Buffering agents include citrate...

  11. Developing suitable buffers to capture transport cycling behavior

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... center-directed ellipse-shaped buffers yielded better results than traditional home-based network buffer types. The ellipse-shaped buffer types could therefore be considered an alternative to more traditional buffers or administrative units in future studies of transport cycling behavior....

  12. Buffering capability and limitations in low dispersion photonic crystal waveguides with elliptical airholes.

    Science.gov (United States)

    Long, Fang; Tian, Huiping; Ji, Yuefeng

    2010-09-01

    A low dispersion photonic crystal waveguide with triangular lattice elliptical airholes is proposed for compact, high-performance optical buffering applications. In the proposed structure, we obtain a negligible-dispersion bandwidth with constant group velocity ranging from c/41 to c/256, by optimizing the major and minor axes of bulk elliptical holes and adjusting the position and the hole size of the first row adjacent to the defect. In addition, the limitations of buffer performance in a dispersion engineering waveguide are well studied. The maximum buffer capacity and the maximum data rate can reach as high as 262bits and 515 Gbits/s, respectively. The corresponding delay time is about 255.4ps.

  13. Buffer of Events as a Markovian Process

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-07-01

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

  14. Buffer of Events as a Markovian Process

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  15. Grass buffers for playas in agricultural landscapes: An annotated bibliography

    Science.gov (United States)

    Melcher, Cynthia P.; Skagen, Susan K.

    2005-01-01

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

  16. 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.

  17. Evaluation the anaerobic digestion performance of solid residual kitchen waste by NaHCO3 buffering

    International Nuclear Information System (INIS)

    Gao, Shumei; Huang, Yue; Yang, Lili; Wang, Hao; Zhao, Mingxing; Xu, Zhiyang; Huang, Zhenxing; Ruan, Wenquan

    2015-01-01

    Highlights: • The maximum methane production of SRKW was 479 mL/gTS added . • Anaerobic digestion capacity increased by 33.3% through NaHCO 3 buffering. • Protease activity was mainly affected by high organic load. - Abstract: Anaerobic digestion has been considered as a promising energy-producing process for kitchen waste treatment. In this paper, the anaerobic digestion (AD) performances of solid residual kitchen waste (SRKW) with or without NaHCO 3 buffering were investigated. The results indicated that the methane production reached the maximum of 479 mL/gTS added at the inoculum to substrate ratio (ISR, based on VS) of 1:1.4 without buffering, accompanied by VS removal rate of 78.91%. Moreover, the anaerobic digestion capacity increased by 33.3% through NaHCO 3 buffering, and the methane yield at ISR 1:2.8 was improved by 48.5% with NaHCO 3 addition. However, the methanogenesis with or without NaHCO 3 buffer was suppressed at ISR 1:3.5, indicated from the lowest methane yield of 55.50 mL/gTS added and high volatile fatty acids concentration of more than 14,000 mg/L. Furthermore, proteins in SRKW were not degraded completely at excessive organic loading, since the concentrations of ammonia nitrogen in ISR 1:3.5 groups with (2738 mg/L) and without NaHCO 3 buffering (2654 mg/L) were lower than the theoretical value of 3500 mg/L and the protease activities in ISR 1:3.5 groups were also inhibited

  18. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  19. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  20. Buffer gas cooling and mixture analysis

    Science.gov (United States)

    Patterson, David S.; Doyle, John M.

    2018-03-06

    An apparatus for spectroscopy of a gas mixture is described. Such an apparatus includes a gas mixing system configured to mix a hot analyte gas that includes at least one analyte species in a gas phase into a cold buffer gas, thereby forming a supersaturated mixture to be provided for spectroscopic analysis.

  1. Body Buffer Zone and Proxemics in Blocking.

    Science.gov (United States)

    Stockwell, John C.; Bahs, Clarence W.

    This paper investigates the effect of personal body buffer zones on compositional arrangements staged by novice directors. Relationships between directors' concepts of personal space and their projection of its dimensions into staging are studied through the use of a variety of proximity measures--distance, area angles of approach, and physical…

  2. Buffering children from marital conflict and dissolution.

    Science.gov (United States)

    Katz, L F; Gottman, J M

    1997-06-01

    Examined several protective mechanisms that may reduce deleterious correlates of marital conflict and marital dissolution in young children. One set of potential buffers focused on parent-child interaction: parental warmth, parental scaffolding/praise, and inhibition of parental rejection. As a second set of potential buffers, each parent was interviewed about their "meta-emotion philosophy"--that is, their feelings about their own emotions, and their attitudes and responses to their children's anger and sadness. The third set of potential buffers concerned intraindividual characteristics of the child, including the child's intelligence and regulatory physiology (basal vagal tone and vagal suppression). Fifty-six families with a preschool child were studied at two time points: when the children were 5 years old (Time 1) and again when the children were 8 years old (Time 2). At Time 1, naturalistic observations of marital and parent-child interaction were conducted and assessment of child regulatory physiology was obtained through measures of basal vagal tone and suppression of vagal tone. Parents were also interviewed individually about their feelings about their own and their children's emotions, and children's intelligence was assessed. At Time 2, assessment of child outcomes were obtained, including observations of peer interaction, mother ratings of behavior problems and mother and teacher ratings of peer aggression, mother ratings of child physical illness, and measures of achievement. Results indicated that all Time 1 buffering factors protected children in face of marital conflict and dissolution.

  3. Baroreflex buffering and susceptibility to vasoactive drugs

    Science.gov (United States)

    Jordan, Jens; Tank, Jens; Shannon, John R.; Diedrich, Andre; Lipp, Axel; Schroder, Christoph; Arnold, Guy; Sharma, Arya M.; Biaggioni, Italo; Robertson, David; hide

    2002-01-01

    BACKGROUND: The overall effect of vasoactive drugs on blood pressure is determined by a combination of the direct effect on vascular tone and an indirect baroreflex-mediated effect, a baroreflex buffering of blood pressure. Differences in baroreflex function affect the responsiveness to vasoactive medications, particularly baroreflex buffering of blood pressure; however, the magnitude is not known. METHODS AND RESULTS: We characterized baroreflex function and responses to vasoactive drugs in patients with idiopathic orthostatic intolerance, patients with essential hypertension, patients with monogenic hypertension and brachydactyly, patients with multiple system atrophy, and control subjects. We used phenylephrine sensitivity during ganglionic blockade as a measure of baroreflex buffering. Phenylephrine (25 microg) increased systolic blood pressure 6+/-1.6 mm Hg in control subjects, 6+/-1.1 mm Hg in orthostatic intolerance patients, 18+/-3.9 mm Hg in patients with essential hypertension, 31+/-3.4 mm Hg in patients with monogenic hypertension, and 25+/-3.4 mm Hg in patients with multiple system atrophy. Similar differences in sensitivities between groups were observed with nitroprusside. The sensitivity to vasoactive drugs was highly correlated with baroreflex buffering function and to a lesser degree with baroreflex control of heart rate. In control subjects, sensitivities to nitroprusside and phenylephrine infusions were correlated with baroreflex heart rate control and sympathetic nerve traffic. CONCLUSIONS: Our findings are consistent with an important effect of baroreflex blood pressure buffering on the sensitivity to vasoactive drugs. They suggest that even moderate changes in baroreflex function may have a substantial effect on the sensitivity to vasoactive medications.

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

    International Nuclear Information System (INIS)

    Boergesson, Lennart; Hernelind, Jan

    2009-10-01

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

  5. 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

  6. Strong Arcwise Connectedness

    OpenAIRE

    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana

    2012-01-01

    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  7. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  8. Wintering bird response to fall mowing of herbaceous buffers

    Science.gov (United States)

    Blank, P.J.; Parks, J.R.; Dively, G.P.

    2011-01-01

    Herbaceous buffers are strips of herbaceous vegetation planted between working agricultural land and streams or wetlands. Mowing is a common maintenance practice to control woody plants and noxious weeds in herbaceous buffers. Buffers enrolled in Maryland's Conservation Reserve Enhancement Program (CREP) cannot be mowed during the primary bird nesting season between 15 April and 15 August. Most mowing of buffers in Maryland occurs in late summer or fall, leaving the vegetation short until the following spring. We studied the response of wintering birds to fall mowing of buffers. We mowed one section to 10-15 cm in 13 buffers and kept another section unmowed. Ninety-two percent of birds detected in buffers were grassland or scrub-shrub species, and 98% of all birds detected were in unmowed buffers. Total bird abundance, species richness, and total avian conservation value were significantly greater in unmowed buffers, and Savannah Sparrows (Passerculus sandwichensis), Song Sparrows (Melospiza melodia), and White-throated Sparrows (Zonotrichia albicollis) were significantly more abundant in unmowed buffers. Wintering bird use of mowed buffers was less than in unmowed buffers. Leaving herbaceous buffers unmowed through winter will likely provide better habitat for wintering birds. ?? 2011 by the Wilson Ornithological Society.

  9. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  10. Retention of ionisable compounds on high-performance liquid chromatography XVII. Estimation of the pH variation of aqueous buffers with the change of the methanol fraction of the mobile phase.

    Science.gov (United States)

    Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

    2007-01-05

    The use of methanol-aqueous buffer mobile phases in HPLC is a common election when performing chromatographic separations of ionisable analytes. The addition of methanol to the aqueous buffer to prepare such a mobile phase changes the buffer capacity and the pH of the solution. In the present work, the variation of these buffer properties is studied for acetic acid-acetate, phosphoric acid-dihydrogenphosphate-hydrogenphosphate, citric acid-dihydrogencitrate-hydrogencitrate-citrate, and ammonium-ammonia buffers. It is well established that the pH change of the buffers depends on the initial concentration and aqueous pH of the buffer, on the percentage of methanol added, and on the particular buffer used. The proposed equations allow the pH estimation of methanol-water buffered mobile phases up to 80% in volume of organic modifier from initial aqueous buffer pH and buffer concentration (before adding methanol) between 0.001 and 0.01 mol L(-1). From both the estimated pH values of the mobile phase and the estimated pKa of the ionisable analytes, it is possible to predict the degree of ionisation of the analytes and therefore, the interpretation of acid-base analytes behaviour in a particular methanol-water buffered mobile phase.

  11. Artificial wetting of buffer material. Small scale

    International Nuclear Information System (INIS)

    Holt, E.; Marjavaara, P.; Loeija, M.

    2011-07-01

    The purpose of this work was to investigate the swelling behaviour of artificially wetted highly compacted bentonite buffer blocks used in deposition holes for nuclear waste containment. The target was to make a preliminary study if homogeneous and rapid swelling of the bentonite is possible to achieve in the gap between the buffer and the rock wall of the deposition hole by artificial wetting. It is expected that the thermal, mechanical, chemical and hydraulic properties of the whole deposition system are better when the bentonite-rock gap is closed. 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 scaling while lowering the risks of bentonite piping and erosion due to potential water flow. In this work, two preliminary sets of tests were done on bentonite block swelling and water filtration through pellets. The majority of work was within the primary tests, where bentonite blocks were confined in a test chamber and swelling was induced by artificial wetting. Water was poured directly into the gap from the top, without the aid of pipes or pressure. After the initial watering, no additional water or moisture was made available for the system during the test duration. The resulting bentonite swelling pressure in both the radial and vertical directions was measured over time. 13 different test scenarios were investigated, including: varying block size of 10 cm height disks or 30 cm blocks, eccentric aligned blocks with gap sizes of 5 and 45 mm, gap sizes of 25 mm or 50 mm, using gap filling with pellets or granular in combined with water, free upward swelling or confinement, addition of water at varying rates, and longer term test duration. In some cases, video images were taken during the swelling, to get an indication of the time until the gap was sealed. After the wetting tests, material properties of the

  12. Isostatic compression of buffer blocks. Middle scale

    International Nuclear Information System (INIS)

    Ritola, J.; Pyy, E.

    2012-01-01

    Manufacturing of buffer components using isostatic compression method has been studied in small scale in 2008 (Laaksonen 2010). These tests included manufacturing of buffer blocks using different bentonite materials and different compression pressures. Isostatic mould technology was also tested, along with different methods to fill the mould, such as vibration and partial vacuum, as well as a stepwise compression of the blocks. The development of manufacturing techniques has continued with small-scale (30 %) blocks (diameter 600 mm) in 2009. This was done in a separate project: Isostatic compression, manufacturing and testing of small scale (D = 600 mm) buffer blocks. The research on the isostatic compression method continued in 2010 in a project aimed to test and examine the isostatic manufacturing process of buffer blocks at 70 % scale (block diameter 1200 to 1300 mm), and the aim was to continue in 2011 with full-scale blocks (diameter 1700 mm). A total of nine bentonite blocks were manufactured at 70 % scale, of which four were ring-shaped and the rest were cylindrical. It is currently not possible to manufacture full-scale blocks, because there is no sufficiently large isostatic press available. However, such a compression unit is expected to be possible to use in the near future. The test results of bentonite blocks, produced with an isostatic pressing method at different presses and at different sizes, suggest that the technical characteristics, for example bulk density and strength values, are somewhat independent of the size of the block, and that the blocks have fairly homogenous characteristics. Water content and compression pressure are the two most important properties determining the characteristics of the compressed blocks. By adjusting these two properties it is fairly easy to produce blocks at a desired density. The commonly used compression pressure in the manufacturing of bentonite blocks is 100 MPa, which compresses bentonite to approximately

  13. 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

  14. Role of buffer gases in optoacoustic spectroscopy

    International Nuclear Information System (INIS)

    Thomas III, L.J.; Kelly, M.J.; Amer, N.M.

    1978-01-01

    The dependence of an acoustically resonant optoacoustic signal on the molecular weight and thermodynamic and transport properpties of the buffer gas is reported. Our results show that careful selection of such gases can significantly increase the sensitivity and flexibility of optoacoustic spectroscopy. We also demonstrate that such thermodynamic quantities as γ (equivalentC/sub p//C/sub v/) and sound velocity can now be measured readily and accurately. Other potential applications are suggested

  15. Acid-base buffering of soils in transitional and transitional-accumulative positions of undisturbed southern-taiga landscapes

    Science.gov (United States)

    Rusakova, E. S.; Ishkova, I. V.; Tolpeshta, I. I.; Sokolova, T. A.

    2012-05-01

    The method of continuous potentiometric titration (CPT) of soil water suspensions was used to evaluate the acid-base buffering of samples from the major genetic horizons of podzolic soils on a slope and soddy gley soils on the adjacent floodplain of a rivulet. In the soils of the slope, the buffering to acid upon titration from the pH of the initial titration point (ITP) to pH 3 in all the horizons was 1.5-2.0 times lower than that in the podzolic soils of the leveled interfluve, which could be due to the active leaching of exchangeable bases and oxalate-soluble aluminum and iron compounds with the later soil flows. In the soddy gley soils, the buffering to acid in the mineral horizons was 2-10 times higher than that in the podzolic soils. A direct dependence of the soil buffering to acid on the total content of exchangeable bases and on the content of oxalate-soluble aluminum compounds was found. A direct dependence of the buffering to basic upon titration from the ITP to pH 10 on the contents of the oxalate-soluble aluminum and organic matter was observed in the mineral horizons of all the studied soils. The soil treatment with Tamm's reagent resulted in the decrease of the buffering to acid in the soddy gley soils of the floodplain, as well as in the decrease of the buffering to basic in the soils on the slopes and in the soddy gley soils. It was also found that the redistribution of the mobile aluminum compounds between the eluvial, transitional, and transitional-accumulative positions in the undisturbed southern taiga landscapes leads to significant spatial differentiation of the acid-base buffering of the mineral soil horizons with a considerable increase in the buffer capacity of the soils within the transitional-accumulative terrain positions.

  16. Methyl Bromide Commodity Fumigation Buffer Zone Lookup Tables

    Science.gov (United States)

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

  17. Adhesion of Lactobacillus species in urine and phosphate buffer to silicone rubber and glass under flow.

    Science.gov (United States)

    Millsap, K W; Reid, G; van der Mei, H C; Busscher, H J

    1997-01-01

    Coating uroepithelial cells or catheter materials with lactobacilli has been shown to retard the development of a uropathogenic biofilm, with biosurfactant production and strong adhesion being two prerequisite properties of the Lactobacillus strains to be employed. In this paper, adhesion of six selected Lactobacillus strains to silicone rubber and glass in urine and in a phosphate buffer was studied using a parallel plate flow chamber. In addition, adhesive cell surface properties of the lactobacilli, i.e. the pH dependences of their zeta potentials and their hydrophobicities by water contact angles, were determined. L. acidophilus ATCC 4356 and L. fermentum B54 were the only strains showing significant adhesion to both hydrophobic silicone rubber and hydrophilic glass, possibly by virtue of their high cell surface hydrophobicities (water contact angles of 68 and 75 degrees, respectively) and small zeta potentials (-10.0 and -8.1 mV in buffer, respectively). Both hydrophobic Lactobacillus strains adhered less well in urine than in buffer. The remaining Lactobacillus strains studied were hydrophilic, with water contact angles between 25 and 36 degrees, and had highly negative zeta potentials, reaching -37.7 mV in buffer. Adhesion of these highly negatively charged, hydrophilic strains in buffer was essentially absent, while for some of these strains minor adhesion in urine was observed. This study demonstrates that the adhesion of lactobacilli to substrata differs with strain hydrophobicity and charge, and that urinary components can affect the ability of hydrophilic Lactobacillus strains to adhere to substrata.

  18. Selected pesticides adsorption and desorption in substrates from artificial wetland and forest buffer.

    Science.gov (United States)

    Passeport, Elodie; Benoit, Pierre; Bergheaud, Valérie; Coquet, Yves; Tournebize, Julien

    2011-07-01

    Buffer zones such as artificial wetlands and forest buffers may help decrease non-point-source pesticide pollution from agricultural catchments. The present study focuses on understanding the role of the substrates mainly found in such buffer zones for pesticide adsorption and desorption. Radiolabeled [(14)C]isoproturon, [(14)C]metazachlor, and [(14)C]epoxiconazole were used to measure adsorption and desorption isotherms on wetland sediments and plants and forest soil and litter from two sites in France. Wetland sediments and forest soil exhibited the most important potential for pesticide adsorption. Wetland plants and forest litter also showed high adsorption coefficients and were associated with highly hysteretic desorption, particularly for the moderately mobile isoproturon and metazachlor. Adsorption of the highly hydrophobic epoxiconazole was strong and associated with weak desorption from all substrates. Calculated sorption coefficients were larger than those classically measured on soils. Isoproturon, metazachlor, and epoxiconazole K(OC) sorption coefficients ranged from 84 to 372, 131 to 255, and 1,356 to 3,939 L/kg, respectively. Therefore, specifically collecting buffer zone substrate sorption data is needed for modeling purposes. Results showed that forests and wetlands present potential for pesticide retention. This may be enhanced by planting vegetation and leaving dead vegetal material in buffer zone design. Copyright © 2011 SETAC.

  19. Bicarbonate buffered peritoneal dialysis fluid upregulates angiopoietin-1 and promotes vessel maturation.

    Directory of Open Access Journals (Sweden)

    Gwendolyn Eich

    Full Text Available Ultrafiltration decline is a progressive issue for patients on chronic peritoneal dialysis (PD and can be caused by peritoneal angiogenesis induced by PD fluids. A recent pediatric trial suggests better preservation of ultrafiltration with bicarbonate versus lactate buffered fluid; underlying molecular mechanisms are unknown.Angiogenic cytokine profile, tube formation capacity and Receptor Tyrosine Kinase translocation were assessed in primary human umbilical vein endothelial cells following incubation with bicarbonate (BPDF and lactate buffered (LPDF, pH neutral PD fluid with low glucose degradation product content and lactate buffered, acidic PD fluid with high glucose degradation product content (CPDF. Peritoneal biopsies from age-, PD-vintage- and dialytic glucose exposure matched, peritonitis-free children on chronic PD underwent automated histomorphometry and immunohistochemistry.In endothelial cells angiopoietin-1 mRNA and protein abundance increased 200% upon incubation with BPDF, but decreased by 70% with LPDF as compared to medium control; angiopoietin-2 remained unchanged. Angiopoietin-1/Angiopoietin-2 protein ratio was 15 and 3-fold increased with BPDF compared to LPDF and medium. Time-lapse microscopy with automated network analysis demonstrated less endothelial cell tube formation with BPDF compared to LPDF and CPDF incubation. Receptor Tyrosine Kinase translocated to the cell membrane in BPDF but not in LPDF or CPDF incubated endothelial cells. In children dialyzed with BPDF peritoneal vessels were larger and angiopoietin-1 abundance in CD31 positive endothelium higher compared to children treated with LPDF.Bicarbonate buffered PD fluid promotes vessel maturation via upregulation of angiopoietin-1 in vitro and in children on dialysis. Our findings suggest a molecular mechanism for the observed superior preservation of ultrafiltration capacity with bicarbonate buffered PD fluid with low glucose degradation product content.

  20. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

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

    Science.gov (United States)

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

    2013-09-17

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

  2. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

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

    Directory of Open Access Journals (Sweden)

    M. RÄTY

    2008-12-01

    Full Text Available 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 sampled from a cultivated field, from buffer zones harvested by grazing (only in a clay soil or by cutting and removing the vegetation, and from buffer zones covered with natural grass vegetation. The samples were equilibrated at a matric potential of -6 kPa and compressed at a normal stress range of 20-400 kPa (7 h, followed by stress removal (1 h. Generally, the clay soil was more compressible than the sandy loam. Due to trampling by cattle, the young grazed buffer zone (0-3 cm had the largest bulk density and the smallest total porosity. For the grazed sites, reduced air permeability (2.7-5.1 × 10-5 m s-1 was found, compared with that of the buffer zone under natural vegetation (15-22 × 10-5 m s-1, indicating decreased pore continuity. Although the old grazed site was easily compressed, compared with the younger site, it showed a greater resilience capacity due to the protective cover of organic residues accumulated on the soil surface.

  4. Stream water responses to timber harvest: Riparian buffer width effectiveness

    Science.gov (United States)

    Barton D. Clinton

    2011-01-01

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

  5. Heed the head: buffer benefits along headwater streams

    Science.gov (United States)

    Rhonda Mazza; Deanna (Dede) Olson

    2015-01-01

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

  6. Concentrated flow paths in riparian buffer zones of southern Illinois

    Science.gov (United States)

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

    2012-01-01

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

  7. 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.

  8. On the road to improved scheduling - fitting activities to capacity

    DEFF Research Database (Denmark)

    Lindhard, Søren Munch; Wandahl, Søren

    2012-01-01

    Last Planner System has through the sounding process increased the reliability of the schedule. The sound activities are moved to a buffer and afterwards selected to the Weekly Work Plans to match capacity. Therefore, in order to maximise productivity it is essential to ensure that the sounding p...

  9. phosphorus sorption capacity as a guide for phosphorus availability

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    Crop response to phosphorus application is often erratic in most soil types in Sudan. This inconsistent response is believed to be due to the alkaline nature of most soils in the country. Phosphorus adsorption isotherms and buffering capacity are powerful tools for predicting response of different soil types to apply P fertilisers.

  10. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  11. Strong interaction and QFD

    International Nuclear Information System (INIS)

    Ebata, T.

    1981-01-01

    With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)

  12. Effects of buffer layer temperature on the magnetic properties of NdFeB thin film magnets

    International Nuclear Information System (INIS)

    Kim, Y.B.; Cho, S.H.; Kim, H.T.; Ryu, K.S.; Lee, S.H.; Lee, K.H.; Kapustin, G.A.

    2004-01-01

    Effects of the buffer layer temperature (T b ) on the magnetic properties and microstructure of [Mo/NdFeB/Mo]-type thin films have been investigated. The Mo-buffer layer with low T b is composed of fine grains while that with high T b has coarse grains. The subsequent NdFeB layer also grows with fine or coarse grains following the buffer layer structure. The NdFeB layer grown on a low T b buffer shows high coercivity and strong perpendicular anisotropy. The best magnetic properties of i H c =1.01 MA/m (12.7 kOe), B r =1.31 T (13.1 kG) and BH max =329 kJ/m 3 (41.4 MGOe) were obtained from the film with T b =400 deg. C

  13. Defining context-specific scenarios to design vegetated buffer zones that limit pesticide transfer via surface runoff.

    Science.gov (United States)

    Carluer, N; Lauvernet, C; Noll, D; Munoz-Carpena, R

    2017-01-01

    When used in addition to environmentally friendly cultural practices, buffer zones can limit the water transfer of pollutants, in particular pesticides, towards water resources. The choice of the buffer zones' type and positioning, considering water pathways and flow components, is crucial. When this choice has been performed, buffer zones dimensions must still be optimized, according to the environment characteristics, which strongly influence their effectiveness. This article presents a method and its associated tools, including VFSMOD model, which aim at optimizing vegetative buffer zones (VFS) sizes, by simulating their transfer mitigation effectiveness. A first application of this methodology is illustrated on a small agricultural watershed in Brittany. A second application, based on the simulation of a large number of scenarios, leads to the elaboration of nomograms. They allow optimizing VFS size in a simpler way from the user's point of view. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

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

    Directory of Open Access Journals (Sweden)

    Jessica S Veysey Powell

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

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

    Science.gov (United States)

    Veysey Powell, Jessica S; Babbitt, Kimberly J

    2015-01-01

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

  17. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  18. Analysis of two production inventory systems with buffer, retrials and different production rates

    Science.gov (United States)

    Jose, K. P.; Nair, Salini S.

    2017-09-01

    This paper considers the comparison of two ( {s,S} ) production inventory systems with retrials of unsatisfied customers. The time for producing and adding each item to the inventory is exponentially distributed with rate β. However, a production rate α β higher than β is used at the beginning of the production. The higher production rate will reduce customers' loss when inventory level approaches zero. The demand from customers is according to a Poisson process. Service times are exponentially distributed. Upon arrival, the customers enter into a buffer of finite capacity. An arriving customer, who finds the buffer full, moves to an orbit. They can retry from there and inter-retrial times are exponentially distributed. The two models differ in the capacity of the buffer. The aim is to find the minimum value of total cost by varying different parameters and compare the efficiency of the models. The optimum value of α corresponding to minimum total cost is an important evaluation. Matrix analytic method is used to find an algorithmic solution to the problem. We also provide several numerical or graphical illustrations.

  19. MISKONSEPSI SISWA PADA MATERI LARUTAN BUFFER

    Directory of Open Access Journals (Sweden)

    Widy Ika Parastuti

    2016-12-01

    Full Text Available Buffer solution is one high school chemistry material found misconceptions on student understanding. Misconceptions identification method by giving some quetion with same type. Misconceptions identified from recurring student answers incorrectly. The study population was the students of class XI IPA at SMAN 1 Malang academic year 2015/2016 with a research subject in class XI MIA 7 number of 32 students. The results obtained by analysis of four kinds of misconceptions. The cause of the misconception is (1 a weak prior knowledge; (2 problems of symbols and mathematical formulas; (3 difficulty understanding the context of the material; (4 problems in generalize. Larutan buffer merupakan salah satu materi kimia SMA yang ditemukan miskonsepsi pada pemahaman siswa. Metode identifikasi miskonsepsi dengan memberikan beberapa soal yang setipe. Miskonsepsi teridentifikasi dari jawaban salah yang berulang siswa. Populasi penelitian ini adalah siswa kelas XI IPA SMA Negeri 1 Malang Tahun ajaran 2015/2016 dengan subjek penelitian kelas XI MIA 7 sejumlah 32 siswa. Hasil analisis diperoleh  empat macam miskonsepsi. Penyebab miskonsepsi adalah (1 pengetahuan awal yang lemah; (2 permasalahan simbol dan rumus matematika; (3 kesulitan memahami konteks materi; (4 permasalahan dalam menggeneralisasikan masalah.

  20. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  1. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  2. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  3. Buffer allocation in an ATM switch with output buffer and speed constraints

    Science.gov (United States)

    Gupta, Anil K.; Georganas, N. D.

    A synchronous nonblocking N times N switch for asynchronous transfer mode (ATM) networks or high speed packet switching networks transporting fixed length packets called cells is considered. Such a switch with output queuing achieves the optimal performance, however it requires the switch fabric to work at the speed of N. In practice the switch may operate L times faster than the input/output trunk. It is assumed that queues at each output port have a limited buffer space and whenever an output queue is full, the back-pressure is applied and the packets are retained at the head of the input queues. The upper bound on the packet loss probability at the input queues in such a switch are computed. To achieve a given packet loss rate, the switch with L equals 2 requires almost the same amount of input and output buffers as with L equals 4 up to 70 percent input load, but as the load increases beyond 70 percent the switch with L equals 4 would require more output buffers and less input buffers in comparison with a switch operating at L equals 2. The performance of a switch with L equals 3 is very similar to that for L equals 4 and is not considered.

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

    African Journals Online (AJOL)

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

  5. Vegetative buffer strips for reducing herbicide transport in runoff: effects of buffer width, vegetation, and season

    Science.gov (United States)

    The effect of vegetative buffer strip (VBS) width, vegetation, and season of the year on herbicide transport in runoff has not been well documented for runoff prone soils. A multi-year replicated plot-scale study was conducted on an eroded claypan soil with the following objectives: 1) assess the ef...

  6. Buffered Versus Non-Buffered Lidocaine With Epinephrine for Mandibular Nerve Block: Clinical Outcomes.

    Science.gov (United States)

    Phero, James A; Nelson, Blake; Davis, Bobby; Dunlop, Natalie; Phillips, Ceib; Reside, Glenn; Tikunov, Andrew P; White, Raymond P

    2017-04-01

    Outcomes for peak blood levels were assessed for buffered 2% lidocaine with 1:100,000 epinephrine compared with non-buffered 2% lidocaine with 1:100,000 epinephrine. In this institutional review board-approved prospective, randomized, double-blinded, crossover trial, the clinical impact of buffered 2% lidocaine with 1:100,000 epinephrine (Anutra Medical, Research Triangle Park, Cary, NC) was compared with the non-buffered drug. Venous blood samples for lidocaine were obtained 30 minutes after a mandibular nerve block with 80 mg of the buffered or unbuffered drug. Two weeks later, the same subjects were tested with the alternate drug combinations. Subjects also reported on pain on injection with a 10-point Likert-type scale and time to lower lip numbness. The explanatory variable was the drug formulation. Outcome variables were subjects' peak blood lidocaine levels, subjective responses to pain on injection, and time to lower lip numbness. Serum lidocaine levels were analyzed with liquid chromatography-mass spectrometry. Statistical analyses were performed using Proc TTEST (SAS 9.3; SAS Institute, Cary, NC), with the crossover option for a 2-period crossover design, to analyze the normally distributed outcome for pain. For non-normally distributed outcomes of blood lidocaine levels and time to lower lip numbness, an assessment of treatment difference was performed using Wilcoxon rank-sum tests with Proc NPAR1WAY (SAS 9.3). Statistical significance was set at a P value less than .05 for all outcomes. Forty-eight percent of subjects were women, half were Caucasian, 22% were African American, and 13% were Asian. Median age was 21 years (interquartile range [IQR], 20-22 yr), and median body weight was 147 lb (IQR, 130-170 lb). Median blood levels (44 blood samples) at 30 minutes were 1.19 μg/L per kilogram of body weight. Mean blood level differences of lidocaine for each patient were significantly lower after nerve block with the buffered drug compared with the

  7. Resource Allocation in Heterogeneous Buffered Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    B. S. Awoyemi

    2017-01-01

    Full Text Available Resources available for operation in cognitive radio networks (CRN are generally limited, making it imperative for efficient resource allocation (RA models to be designed for them. However, in most RA designs, a significant limiting factor to the RA’s productivity has hitherto been mostly ignored, the fact that different users or user categories do have different delay tolerance profiles. To address this, in this paper, an appropriate RA model for heterogeneous CRN with delay considerations is developed and analysed. In the model, the demands of users are first categorised and then, based on the distances of users from the controlling secondary user base station and with the assumption that the users are mobile, the user demands are placed in different queues having different service capacities and the resulting network is analysed using queueing theory. Furthermore, to achieve optimality in the RA process, an important concept is introduced whereby some demands from one queue are moved to another queue where they have a better chance of enhanced service, thereby giving rise to the possibility of an improvement in the overall performance of the network. The performance results obtained from the analysis, particularly the blocking probability and network throughput, show that the queueing model incorporated into the RA process can help in achieving optimality for the heterogeneous CRN with buffered data.

  8. [Buffering capacity of the vitreous body in aggressive posterior retinopathy of prematurity].

    Science.gov (United States)

    Amkhanitskaia, L I; Sidorenko, E I; Nikolaeva, G V; Kuznetsova, Iu D

    2014-01-01

    To investigate the role of vitreous body changes in the pathogenesis of aggressive posterior retinopathy of prematurity. The study included 60 children with stage 4-5 retinopathy of prematurity demonstrating either classical or aggressive posterior form of progression. In all cases vitreous samples for laboratory testing were taken during surgery. The study showed that aggressive posterior retinopathy of prematurity is associated with more significant metabolic changes in comparison with classical form of the disease. The degree of biochemical imbalance of the vitreous appeared directly related to the stage of the disease, which was determined by the type and extent of retinal detachment. Volcano-shaped retinal detachment with intensive exudation within the posterior eye segment is considered the most severe variant of aggressive posterior retinopathy of prematurity. Aggressive posterior retinopathy of prematurity is characterized by substantial disturbance of metabolism of the vitreous body, which contributes to exudation and proliferation, thus aggravating the course of the disease and worsening the prognosis.

  9. Estimation of the carrying capacity of grazing land in the buffer zone ...

    African Journals Online (AJOL)

    The study revealed that the Dry matter yield (DMY) from natural pastures was 3.54 tones ha-1yr-1 and the Potential Dry Matter (PDM) production from crop residues was 33.130 tons ha-1 yr-1, the total area under grazing was 49,197ha, the total feed resource potentially available for livestock = 205,320 tons yr-1 and the ...

  10. Experiments on thermal conductivity in buffer materials for geologic repository

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  11. Lack of cations in flow cytometry buffers affect fluorescence signals by reducing membrane stability and viability of Escherichia coli strains.

    Science.gov (United States)

    Tomasek, Kathrin; Bergmiller, Tobias; Guet, Călin C

    2018-02-20

    Buffers are essential for diluting bacterial cultures for flow cytometry analysis in order to study bacterial physiology and gene expression parameters based on fluorescence signals. Using a variety of constitutively expressed fluorescent proteins in Escherichia coli K-12 strain MG1655, we found strong artifactual changes in fluorescence levels after dilution into the commonly used flow cytometry buffer phosphate-buffered saline (PBS) and two other buffer solutions, Tris-HCl and M9 salts. These changes appeared very rapidly after dilution, and were linked to increased membrane permeability and loss in cell viability. We observed buffer-related effects in several different E. coli strains, K-12, C and W, but not E. coli B, which can be partially explained by differences in lipopolysaccharide (LPS) and outer membrane composition. Supplementing the buffers with divalent cations responsible for outer membrane stability, Mg 2+ and Ca 2+ , preserved fluorescence signals, membrane integrity and viability of E. coli. Thus, stabilizing the bacterial outer membrane is essential for precise and unbiased measurements of fluorescence parameters using flow cytometry. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Stream buffer effectiveness in an agriculturally influenced area, southwestern Georgia: responses of water quality, macroinvertebrates, and amphibians.

    Science.gov (United States)

    Muenz, Tara K; Golladay, Stephen W; Vellidis, George; Smith, Lora L

    2006-01-01

    To determine useful metrics for assessing stream water quality in the Southeastern Coastal Plain, we examined differences among two buffered and three unbuffered streams in an agricultural landscape in southwestern Georgia. Potential indicators included amphibian diversity and abundance, aquatic macroinvertebrate populations, riparian vegetative structure, water quality, and stream physical parameters. Variability among sites and treatments (buffered vs. unbuffered) existed, with sites in the same treatment as most similar, and disturbances from a nearby eroding gully strongly affecting one unbuffered site. Of the invertebrate metrics examined, percentages of clingers, Ephemeroptera-Plecoptera-Trichoptera (EPT), Elmidae (Coleoptera), Crustacea (Decapoda and Amphipoda), and dipterans were found to be possible indicators of stream health for perennial streams within this region. Overall, buffered sites showed higher percentages of sensitive invertebrate groups and showed lower and more stable concentrations of nitrate N, suspended solids, and fecal coliforms (FCs). Percent canopy cover was similar among sites; however, riparian vegetative coverage and percent leaf litter were greatest at buffered sites. No differences in amphibian abundance, presence, and absence within the riparian area were apparent between sites; however, instream larval salamanders were more abundant at buffered streams. In this study, stream buffers appeared to decrease nutrient and sediment loads to adjacent streams, enhancing overall water quality. Selected benthic macroinvertebrate metrics and amphibian abundance also appeared sensitive to agricultural influences. Amphibians show potential as indicator candidates, however further information is needed on their responses and tolerances to disturbances from the microhabitat to landscape levels.

  13. Relaxation to equilibrium following photoacid dissociation in mineral acids and buffer solutions

    International Nuclear Information System (INIS)

    Pines, D; Nibbering, E T J; Pines, E

    2007-01-01

    The relaxation to the dissociation equilibrium of a weak acid undergoing a transient pK a change in the presence of a strong mineral acid has been the subject of considerable interest both experimentally and theoretically. Here we compare this process with the analogue event taking place in a buffer solution of a weak carboxylic acid. The comparison has been performed in identical pH and ionic strength conditions and at a sufficiently short timescale where the buffer can only affect the weak acid relaxation by proton scavenging. Although the two relaxation processes have been found to differ in their temporal behaviour, they have both resulted in identical equilibrium amplitudes of the photoacid. This observation reassures the well-known chemical wisdom that pK a values measured in buffer solutions do not depend on the specific chemical reactivity of the buffer. We analyse the essentially many-body relaxation problem in terms of a re-normalized geminate recombination reaction which persists over longer times than the exponential relaxation to equilibrium of homogenously distributed populations of the reactants

  14. Surface Treatments of Nb by Buffered Electropolishing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Andy T. [JLAB; Rimmer, Robert A. [JLAB; Ciovati, Gianluigi [JLAB; Manus, Robert L. [JLAb; Reece, Charles E. [JLAB; Williams, J. S. [JLAB; Eozénou, F. [CEA, Gif-sur-Yvette; Jin, S. [PKU/IHIP, Beijing; Lin, L. [PKU/IHIP, Beijing; Lu, X.Y. [PKU/IHIP, Beijing; Mammosser, John D. [JLAB; Wang, E. [BNL

    2009-11-01

    Buffered electropolishing (BEP) is a Nb surface treatment technique developed at Jefferson Lab1. Experimental results obtained from flat Nb samples show2-4 that BEP can produce a surface finish much smoother than that produced by the conventional electropolishing (EP), while Nb removal rate can be as high as 4.67 μm/min. This new technique has been applied to the treatments of Nb SRF single cell cavity employing a vertical polishing system5 constructed at JLab as well as a horizontal polishing system at CEA Saclay. Preliminary results show that the accelerating gradient can reach 32 MV/m for a large grain cavity and 26.7 MV/m for a regular grain cavity. In this presentation, the latest progresses from the international collaboration between Peking University, CEA Saclay, and JLab on BEP will be summarized.

  15. Buffer mass test - Heater design and operation

    International Nuclear Information System (INIS)

    Nilsson, J.; Ramqvist, G.; Pusch, R.

    1984-06-01

    The nuclear waste is assumed to be contained in cylindrical metal canisters which will be inserted in deposition holes. Heat is generated as a result of the continuing decay of the radioactive waste and in the Buffer Mass Test (BMT) the heat flux expected from such canisters was simulated by the use of six electric heaters. the heaters were constructed partly of aluminium and partly of stainless steel. They are 1520 mm in length and 380 mm in diameter, and give a maximum power output of 3000 W. The heater power can be monitored by panel meters coupled to a computer-based data acquisition system. Both the heater and the control system were manufactured with a high degree of redundancy in case of component failure. This report describes the design, construction, testing, installation and necessary tools for heater installation and dismantling operation. (author)

  16. Auto-protective redox buffering systems in stimulated macrophages

    Directory of Open Access Journals (Sweden)

    Negre Olivier

    2002-03-01

    Full Text Available Abstract Background Macrophages, upon encounter with micro-organisms or stimulated by cytokines, produce various effector molecules aimed at destroying the foreign agents and protecting the organism. Reactive oxygen species (ROS and reactive nitrogen species (RNS are front line molecules exerting strong cytotoxic activities against micro-organisms and many cells, including macrophages themselves. Using cells of the murine macrophage cell line (RAW 264.7 stimulated in vitro with lipopolysaccharide (LPS and/or interferon (IFN-γ, which induce strong endogenous NO production, we examined by which mechanisms a fraction of activated macrophages protect themselves from nitrosative stress and manage to escape destruction? Results We observed that survivors (10–50% depending on the experiments had acquired a resistant phenotype being capable to survive when further exposed in vitro to an apoptosis inducing dose of the NO donor compound DETA-NO. These cells expressed an increased steady-state levels of Mn SOD, CuZn SOD and catalase mRNA (130–200%, together with an increased activity of the corresponding enzymes. Intracellular concentration of glutathione was also increased (× 3.5 fold at 6 hours, still maintained × 5.2 fold at 48 hours. Neither mRNA for glutathione peroxydase, γ-glutamylcysteine synthase and glutathione reductase, nor thioredoxine and thioredoxine reductase, were significantly modified. Additional experiments in which RAW 264.7 cells were stimulated with LPS and/or IFN-γ in the presence of relatively specific inhibitors of both Mn and Cu/Zn SOD, aminotriazol (ATZ catalase inhibitor and buthionine sulfoximine (BSO glutathione inhibitor, showed that inhibiting LPS-induced up-regulation of intracellular redox buffering systems also prevented acquisition of the resistant phenotype. Conclusions Our data suggest a direct causal relationship between survival of a fraction of macrophages and a up-regulation of key sets of auto

  17. Behavior and nutritional condition buffer a large-bodied endotherm against direct and indirect effects of climate

    Science.gov (United States)

    Ryan A. Long; R. Terry Bowyer; Warren P. Porter; Paul Mathewson; Kevin L. Monteith; John G. Kie

    2014-01-01

    Temporal changes in net energy balance of animals strongly influence fitness; consequently, natural selection should favor behaviors that increase net energy balance by buffering individuals against negative effects of environmental variation. The relative importance of behavioral responses to climate-induced variation in costs vs. supplies of energy, however, is...

  18. Moisture Buffer Effect and its Impact on Indoor Environment

    DEFF Research Database (Denmark)

    Zhang, Mingjie; Qin, Menghao; Chen, Zhi

    2017-01-01

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

  19. Solubilization of proteins: the importance of lysis buffer choice.

    Science.gov (United States)

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

    2015-01-01

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

  20. 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.

  1. Back contact buffer layer for thin-film solar cells

    Science.gov (United States)

    Compaan, Alvin D.; Plotnikov, Victor V.

    2014-09-09

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

  2. 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.

  3. Strong ion difference in urine: new perspectives in acid-base assessment.

    OpenAIRE

    Gattinoni, L.; Carlesso, E.; Cadringher, P.; Caironi, P.

    2006-01-01

    The plasmatic strong ion difference (SID) is the difference between positively and negatively charged strong ions. At pH 7.4, temperature 37°C and partial carbon dioxide tension 40 mmHg, the ideal value of SID is 42 mEq/l. The buffer base is the sum of negatively charged weak acids ([HCO3 -], [A-], [H2PO4 -]) and its normal value is 42 mEq/l. According to the law of electroneutrality, the amount of positive and negative charges must be equal, and therefore the SID value is equal to the buffer...

  4. MES buffer affects Arabidopsis root apex zonation and root growth by suppressing superoxide generation in root apex

    Directory of Open Access Journals (Sweden)

    Tomoko eKagenishi

    2016-02-01

    Full Text Available In plants, growth of roots and root hairs is regulated by the fine cellular control of pH and reactive oxygen species. MES, 2-(N-morpholinoethanesulfonic acid as one of the Good’s buffers has broadly been used for buffering medium, and it is thought to suit for plant growth with the concentration at 0.1% (w/v because the buffer capacity of MES ranging pH 5.5-7.0 (for Arabidopsis, pH 5.8. However, many reports have shown that, in nature, roots require different pH values on the surface of specific root apex zones, namely meristem, transition zone and elongation zone. Despite the fact that roots always grow on a media containing buffer molecule, little is known about impact of MES on root growth. Here, we have checked the effects of different concentrations of MES buffer using growing roots of Arabidopsis thaliana. Our results show that 1% of MES significantly inhibited root growth, the number of root hairs and length of meristem, whereas 0.1% promoted root growth and root apex area (region spanning from the root tip up to the transition zone. Furthermore, superoxide generation in root apex disappeared at 1% of MES. These results suggest that MES disturbs normal root morphogenesis by changing the reactive oxygen species (ROS homeostasis in root apex.

  5. MES Buffer Affects Arabidopsis Root Apex Zonation and Root Growth by Suppressing Superoxide Generation in Root Apex.

    Science.gov (United States)

    Kagenishi, Tomoko; Yokawa, Ken; Baluška, František

    2016-01-01

    In plants, growth of roots and root hairs is regulated by the fine cellular control of pH and reactive oxygen species (ROS). MES, 2-(N-morpholino)ethanesulfonic acid as one of the Good's buffers has broadly been used for buffering medium, and it is thought to suit for plant growth with the concentration at 0.1% (w/v) because the buffer capacity of MES ranging pH 5.5-7.0 (for Arabidopsis, pH 5.8). However, many reports have shown that, in nature, roots require different pH values on the surface of specific root apex zones, namely meristem, transition zone, and elongation zone. Despite the fact that roots always grow on a media containing buffer molecule, little is known about impact of MES on root growth. Here, we have checked the effects of different concentrations of MES buffer using growing roots of Arabidopsis thaliana. Our results show that 1% of MES significantly inhibited root growth, the number of root hairs and length of meristem, whereas 0.1% promoted root growth and root apex area (region spanning from the root tip up to the transition zone). Furthermore, superoxide generation in root apex disappeared at 1% of MES. These results suggest that MES disturbs normal root morphogenesis by changing the ROS homeostasis in root apex.

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

    International Nuclear Information System (INIS)

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

    1997-12-01

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

  7. A queueing model for error control of partial buffer sharing in ATM

    Directory of Open Access Journals (Sweden)

    Ahn Boo Yong

    1999-01-01

    Full Text Available We model the error control of the partial buffer sharing of ATM by a queueing system M 1 , M 2 / G / 1 / K + 1 with threshold and instantaneous Bernoulli feedback. We first derive the system equations and develop a recursive method to compute the loss probabilities at an arbitrary time epoch. We then build an approximation scheme to compute the mean waiting time of each class of cells. An algorithm is developed for finding the optimal threshold and queue capacity for a given quality of service.

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

    International Nuclear Information System (INIS)

    Pusch, Roland

    2003-01-01

    The present document collects conceptual and mathematical models that have been proposed for describing the performance of buffers and backfills and processes in them that are related to their function under repository conditions. As in the preceding parts the following types of sealing components are defined. By definition, the buffer shall be so composed that radionuclide transport in the clay-based barriers takes place by diffusion and not by water flow, which makes it important to predict the extent and rate of diffusive transport of such elements through the buffer. It depends strongly on the density and homogeneity of the buffer, which in turn depend on the maturation rate and the ultimate degree of homogeneity of the buffer. They are influenced by the temperature and temperature gradient that exist in the initial phase of water saturation, in which the hydraulic interaction with the near field rock is also important. Design of suitable buffer and backfills hence requires that their performance can be quantified, which requires that the various processes can be modeled conceptually and expressed in mathematical form. Based on the present knowledge this can only be made for some of the involved mechanisms and for coupled processes there is still a very limited number of mathematically expressed computational codes. The models referred to here are conceptual in the first place, defining the respective processes and material property parameters. The quick development of computational tools, numerical as well as analytical, makes it irrelevant to give detailed descriptions of them, while the various assumptions on which they are based - especially the conceptual models - have been considered in some detail. The models of practical use are only described in general terms and examples at the end of the respective chapter illustrate how they can be utilized. A very important fact is that transport and rheological processes in a repository are hardly ever of simple

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

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland [Geodevelopment AB, Lund (Sweden)

    2003-01-15

    The present document collects conceptual and mathematical models that have been proposed for describing the performance of buffers and backfills and processes in them that are related to their function under repository conditions. As in the preceding parts the following types of sealing components are defined. By definition, the buffer shall be so composed that radionuclide transport in the clay-based barriers takes place by diffusion and not by water flow, which makes it important to predict the extent and rate of diffusive transport of such elements through the buffer. It depends strongly on the density and homogeneity of the buffer, which in turn depend on the maturation rate and the ultimate degree of homogeneity of the buffer. They are influenced by the temperature and temperature gradient that exist in the initial phase of water saturation, in which the hydraulic interaction with the near field rock is also important. Design of suitable buffer and backfills hence requires that their performance can be quantified, which requires that the various processes can be modeled conceptually and expressed in mathematical form. Based on the present knowledge this can only be made for some of the involved mechanisms and for coupled processes there is still a very limited number of mathematically expressed computational codes. The models referred to here are conceptual in the first place, defining the respective processes and material property parameters. The quick development of computational tools, numerical as well as analytical, makes it irrelevant to give detailed descriptions of them, while the various assumptions on which they are based - especially the conceptual models - have been considered in some detail. The models of practical use are only described in general terms and examples at the end of the respective chapter illustrate how they can be utilized. A very important fact is that transport and rheological processes in a repository are hardly ever of simple

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-12-01

    to simulate the acidimetric/alkalimetric titration of pore solutions equilibrated with water-saturated, compacted MX-80 bentonite. Calculation of the inverse of derivatives of the simulated titration curve provides estimates of the pH buffer intensity. Analytical and adaptive grid numerical models are then used to simulate the propagation velocity of the pH front through the buffer. Two assumptions. that are adopted in these models may be questionable, however: 1) that the region near the pH front is a closed chemical system, and 2) that local and partial equilibrium is sustained as H{sup +} diffuses into this region. A rigorous reactive transport modeling approach may be needed to assess the validity of these assumptions. A reaction-path model appropriate for advection-dominated groundwater flow in one spatial dimension is also used in this study to evaluate the relation between chemical buffering due to water-rock interaction and the migration velocity of a pH front in a granitic host rock. The modeling approach is based on the stationary state approximation to the governing mass-transport equations controlling coupled fluid flow and water-rock interaction. A consequence of stationary-state behavior is that the migration velocity of a reaction front is fixed relative to the Darcy flow velocity. An analytical expression consistent with this behavior predicts that front velocities are attenuated relative to the flow velocity by a retardation factor, which is similar, and in some cases identical, to the buffer intensity of reactions that control the front. A key assumption in this model is that the groundwater system involves purely advective transport in a homogeneous porous medium. This may be unrealistic in real groundwater systems, except over extremely limited scales of space and time. Results of both the near-field and far-field models indicate that buffering may strongly attenuate the migration velocities of reaction fronts, and that front velocities are

  11. Dynamical Origin of the Effective Storage Capacity in the Brain's Working Memory

    Science.gov (United States)

    Bick, Christian; Rabinovich, Mikhail I.

    2009-11-01

    The capacity of working memory (WM), a short-term buffer for information in the brain, is limited. We suggest a model for sequential WM that is based upon winnerless competition amongst representations of available informational items. Analytical results for the underlying mathematical model relate WM capacity and relative lateral inhibition in the corresponding neural network. This implies an upper bound for WM capacity, which is, under reasonable neurobiological assumptions, close to the “magical number seven.”

  12. Arise, amphibians: stream buffers affect more than fish.

    Science.gov (United States)

    Sally. Duncan

    2003-01-01

    Buffers along streams cover a tremendous proportion of the land base in the forested systems of the western Pacific Northwest. These buffers were designated primarily to conserve and restore habitat for salmon and trout, but conservation of habitat for a number of other organisms also has been implicit in their design. Recent research evaluated the importance of...

  13. Design and analysis of hybrid optical and electronic buffer based ...

    Indian Academy of Sciences (India)

    ARUNENDRA SINGH

    2018-03-10

    Mar 10, 2018 ... Abstract. Optical packet switching has the potential to be used as next generation data transfer technology. This paper, introduces an Arrayed Waveguide Gratings (AWG) switch where hybrid buffer (electronic ? op- tical) is used for the buffering of contending packets. Power budget analysis has been ...

  14. Effects of riparian buffers on hydrology of northern seasonal ponds

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

    Kathleen A. Dwire; Richard R. Lowrance

    2006-01-01

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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  17. 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.

  18. Methods for improved growth of group III nitride buffer layers

    Science.gov (United States)

    Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

    2014-07-15

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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  20. 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.

  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. 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.

  3. Total iron binding capacity

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003489.htm Total iron binding capacity To use the sharing features on this page, please enable JavaScript. Total iron binding capacity (TIBC) is a blood test to ...

  4. Responsibility and Capacities

    DEFF Research Database (Denmark)

    Ryberg, Jesper

    2014-01-01

    That responsible moral agency presupposes certain mental capacities, constitutes a widely accepted view among theorists. Moreover, it is often assumed that degrees in the development of the relevant capacities co-vary with degrees of responsibility. In this article it is argued that, the move from...... the view that responsibility requires certain mental capacities to the position that degrees of responsibility co-vary with degrees of the development of the mental capacities, is premature....

  5. DNA-Catalyzed Henry Reaction in Pure Water and the Striking Influence of Organic Buffer Systems

    Directory of Open Access Journals (Sweden)

    Marleen Häring

    2015-03-01

    Full Text Available In this manuscript we report a critical evaluation of the ability of natural DNA to mediate the nitroaldol (Henry reaction at physiological temperature in pure water. Under these conditions, no background reaction took place (i.e., control experiment without DNA. Both heteroaromatic aldehydes (e.g., 2-pyridinecarboxaldehyde and aromatic aldehydes bearing strong or moderate electron-withdrawing groups reacted satisfactorily with nitromethane obeying first order kinetics and affording the corresponding β-nitroalcohols in good yields within 24 h. In contrast, aliphatic aldehydes and aromatic aldehydes having electron-donating groups either did not react or were poorly converted. Moreover, we discovered that a number of metal-free organic buffers efficiently promote the Henry reaction when they were used as reaction media without adding external catalysts. This constitutes an important observation because the influence of organic buffers in chemical processes has been traditionally underestimated.

  6. Multi-Buffer Simulations for Trace Language Inclusion

    Directory of Open Access Journals (Sweden)

    Milka Hutagalung

    2016-09-01

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

  7. 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...... 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......-adaptive characterisation of the moisture buffer potential of interior elements and corroborates their superposition toward a room-enclosure moisture buffer potential. It is verified that this enables qualitative comparison of enclosures in relation to interior moisture buffering. It is moreover demonstrated that it forms...

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

    International Nuclear Information System (INIS)

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

    2010-11-01

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

  9. Replenishing data descriptors in a DMA injection FIFO buffer

    Science.gov (United States)

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

    2011-10-11

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

  10. Smooth Nb surfaces fabricated by buffered electropolishing

    International Nuclear Information System (INIS)

    Wu, Andy T.; Mammosser, John; Phillips, Larry; Delayen, Jean; Reece, Charles; Wilkerson, Amy; Smith, David; Ike, Robert

    2007-01-01

    It was demonstrated that smooth Nb surfaces could be obtained through buffered electropolishing (BEP) employing an electrolyte consisting of lactic, sulfuric, and hydrofluoric acids. Parameters that control the polishing process were optimized to achieve a smooth surface finish. The polishing rate of BEP was determined to be 0.646 μm/min which was much higher than 0.381 μm/min achieved by the conventional electropolishing (EP) process widely used in the superconducting radio frequency (SRF) community. Root mean square measurements using a 3D profilometer revealed that Nb surfaces treated by BEP were an order of magnitude smoother than those treated by the optimized EP process. The chemical composition of the Nb surfaces after BEP was analyzed by static and dynamic secondary ion mass spectrometry (SIMS) systems. SIMS results implied that the surface oxide structure of Nb might be more complicated than what usually believed and could be inhomogeneous. Preliminary results of BEP on Nb SRF single cell cavities and half-cells were reported. It was shown that smooth and bright surfaces could be obtained in 1800 s when the electric field inside a SRF cavity was uniform during a BEP process. This study showed that BEP is a promising technique for surface treatment on Nb SRF cavities to be used in particle accelerators

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

    International Nuclear Information System (INIS)

    Sugita, Yutaka

    2002-12-01

    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. CDMA systems capacity engineering

    CERN Document Server

    Kim, Kiseon

    2004-01-01

    This new hands-on resource tackles capacity planning and engineering issues that are crucial to optimizing wireless communication systems performance. Going beyond the system physical level and investigating CDMA system capacity at the service level, this volume is the single-source for engineering and analyzing systems capacity and resources.

  13. Phosphorus retention in riparian buffers: review of their efficiency.

    Science.gov (United States)

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

    2009-01-01

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

  14. Use of clays as buffers in radioactive repositories

    International Nuclear Information System (INIS)

    Pusch, R.

    1983-05-01

    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)

  15. BENTO buffer development program in Finland - Key issues

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  16. Lack of Buffering by Composites Promotes Shift to More Cariogenic Bacteria.

    Science.gov (United States)

    Nedeljkovic, I; De Munck, J; Slomka, V; Van Meerbeek, B; Teughels, W; Van Landuyt, K L

    2016-07-01

    Secondary caries (SC) remains a very important problem with composite restorations. The objectives of this study were to test the acid-buffering ability of several restorative materials and to evaluate whether buffering of the restorative material has an impact on the microbial composition of the biofilm. Disk-shaped specimens of conventional composite, composite with surface prereacted glass-ionomer filler particles (so-called giomer), glass-ionomer cement (GIC), amalgam, and hydroxyapatite (HAp) (control) were exposed to aqueous solutions with pH 4, 5, 6, and 7 and to the medium containing bacteria-produced acids, and pH changes were recorded over several days. Next, material specimens were immersed in bacterial growth medium with pH adjusted to 5. After a 24-h incubation, the extracts were collected and inoculated with a cariogenic (Streptococcus mutans) and a noncariogenic (Streptococcus sanguinis) species. The bacterial growth was monitored both in a single-species model by spectrophotometry and in a dual-species model by viability quantitative polymerase chain reaction. Amalgam and HAp showed the strongest acid-buffering ability, followed by the GIC and the giomer, while the conventional composite did not exhibit any buffering capacity. Furthermore, due to the lack of acid-buffering abilities, composite was not able to increase the pH of the medium (pH 5), which, in the absence of antibacterial properties, allowed the growth of S. mutans, while the growth of S. sanguinis, a less aciduric species, was completely inhibited. A similar effect was observed when bacteria were cultured together: there was a higher percentage of S. mutans and lower percentage of S. sanguinis with the conventional composite than with other materials and HAp. In conclusion, conventional composites lack the ability to increase the local pH, which leads to the outgrowth of more acidogenic/aciduric bacteria and higher cariogenicity of the biofilm. Together with lack of antibacterial

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

    DEFF Research Database (Denmark)

    Pallewatta, Pallewatta G A P

    which consist of YBCO superconducting coatings on cube-textured Ni based alloy tapes.  Before the epitaxial deposition this superconducting layer, a buffer layer is applied on the metal substrate as a diffusion barrier which is also required to transfer the strong texture of the underlying substrate......, allowing the epitaxial growth of the superconducting layer. State-of-the-art coated conductor hetero structures are mainly based on CeO2 based buffer stacks that consist of a sequence of several different buffer layers. Buffer layers deposited by continuous chemical deposition techniques, which...... are the most suitable for large scale production, use to suffer from porosity and cracks that lead to material diffusion from the metal substrate into the superconductor as well as oxidation of the metal during high-temperature processing of the buffer layer. SrTiO3 buffer layers have attracted interest due...

  18. Effect of buffer general acid-base catalysis on the stereoselectivity of ester and thioester H/D exchange in D2O.

    Science.gov (United States)

    Mohrig, Jerry R; Reiter, Nicholas J; Kirk, Randy; Zawadski, Michelle R; Lamarre-Vincent, Nathan

    2011-04-06

    As part of a comprehensive investigation on the stereochemistry of base-catalyzed 1,2-elimination and H/D exchange reactions of carbonyl compounds, we have found that the stereoselectivity of H/D exchange of 3-hydroxybutyryl N-acetylcysteamine (3) in D(2)O is strongly influenced by the presence of buffers. This buffer effect is also operative with a simple acyclic ester, ethyl 3-methoxybutanoate (7). Buffers whose general-acid components are cyclic tertiary ammonium ions are particularly effective in changing the stereoselectivity. (2)H NMR analysis showed that without buffer, H/D exchange of 3 produces 81-82% of the 2R*, 3R* diastereomer of 2-deuterio 3 (the anti product). In the presence of 0.33 M 3-quinuclidinone buffer, only 44% of the 2R*, 3R* diastereomer was formed. With ester 7, the stereoselectivity went from 93-94% in DO(-)/D(2)O to 60% in the presence of buffer. Phosphate buffer, as well as others, also showed substantial effects. The results are put into the context of what is known about the mechanism of H/D exchange of esters and thioesters, and the relevance of the buffer effect on the mechanism of the enoyl-CoA hydratase reaction is discussed. It is likely that hydrogen bonding in the enolate-buffer acid encounter complex is an important stereochemical determinant in producing a greater amount of the 2R*, 3S* diastereomer (the syn product). Studies that involve the protonation of enolate anions in D(2)O need to include the buffer general acid in any understanding of the stereoselectivity. © 2011 American Chemical Society

  19. Buffer-Mediated Effects of Clearcutting on In-Pool Amphibian Productivity: Can Aquatic Processes Compensate for Terrestrial Habitat Disturbance?

    Directory of Open Access Journals (Sweden)

    Jessica S. Veysey Powell

    2016-12-01

    Full Text Available Natural resource extraction and wildlife conservation are often perceived as incompatible. For wetland-dependent amphibians, forested buffers may mitigate timber-harvest impacts, but little empirical research has focused on buffers around lentic habitats. We conducted a landscape experiment to examine how spotted salamander and wood frog reproductive output (i.e., eggmass and metamorph production respond to clearcutting mediated by buffers of different widths (i.e., uncut, 30 m buffer, 100 m buffer at ephemeral pools in an industrial forest. We found complex interactions between buffer treatment and reproductive output, which were strongly mediated by hydroperiod. Overall, reproductive output was most sensitive at 30 m-buffer pools and for salamanders, but responses diverged across productivity metrics even within these categories. Notably, for both cut treatments over time, while salamander eggmass abundance decreased, metamorph productivity (i.e., snout-vent length [SVL] and abundance tended to increase. For example, average metamorph SVLs were predicted to lengthen between 0.2 and 0.4 mm per year post-cut. Additionally, typical relationships between reproductive output and hydroperiod (as indicated by the reference treatment were disrupted for both species in both cut treatments. For example, long-hydroperiod pools produced more salamander metamorphs than short-hydroperiod pools in both the reference and 30 m-buffer treatments, but the rate of increase was lower in the 30 m-buffer treatment such that a long-hydroperiod pool in the reference treatment was predicted to produce, on average, 24 more metamorphs than a similar pool in the 30 m-buffer treatment. From a conservation perspective, our results highlight the importance of evaluating both terrestrial and aquatic responses to terrestrial habitat disturbance, since responses may be reinforcing (i.e., exert similarly positive or negative effects, with the potential for amplification in the

  20. Intermixing at the heterointerface between ZnS /Zn(S,O) bilayer buffer and CuInS2 thin film solar cell absorber

    Science.gov (United States)

    Bär, M.; Ennaoui, A.; Klaer, J.; Kropp, T.; Sáez-Araoz, R.; Lehmann, S.; Grimm, A.; Lauermann, I.; Loreck, Ch.; Sokoll, St.; Schock, H.-W.; Fischer, Ch.-H.; Lux-Steiner, M. C.; Jung, Ch.

    2006-09-01

    The application of Zn compounds as buffer layers was recently extended to wide-gap CuInS2 (CIS) based thin-film solar cells. Using an alternative chemical deposition route for the buffer preparation aiming at the deposition of a single-layer, nominal ZnS buffer without the need for any toxic reactants such as hydrazine has helped us to achieve a similar efficiency as respective CdS-buffered reference devices. After identifying the deposited Zn compound, as ZnS /Zn(S,O) bilayer buffer in former investigations [M. Bär et al., J. Appl. Phys. 99, 123503 (2006)], this time the focus lies on potential diffusion/intermixing processes at the buffer/absorber interface possibly, clarifying the effect of the heat treatment, which drastically enhances the device performance of respective final solar cells. The interface formation was investigated by x-ray photoelectron and x-ray excited Auger electron spectroscopy. In addition, photoelectron spectroscopy (PES) measurements were also conducted using tunable monochromatized synchrotron radiation in order to gain depth-resolved information. The buffer side of the buffer/absorber heterointerface was investigated by means of the characterization of Zn(S ,O)/ZnS/CIS structures where the ZnS /Zn(S,O) bilayer buffer was deposited successively by different deposition times. In order to make the (in terms of PES information depth) deeply buried absorber side of the buffer/absorber heterointerface accessible for characterization, in these cases the buffer layer was etched away by dilute HClaq. We found indications that while (out-leached) Cu from the absorber layer forms together with the educts in the chemical bath a [Zn(1-Z ),Cu2Z]S-like interlayer between buffer and absorber, Zn is incorporated in the uppermost region of the absorber. Both effects are strongly enhanced by postannealing the Zn(S ,O)/ZnS/CIS samples. However, it was determined that the major fraction of the Cu and Zn can be found quite close to the heterointerface in

  1. 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

  2. Temperature Buffer Test. Final THM modelling

    International Nuclear Information System (INIS)

    Aakesson, Mattias; Malmberg, Daniel; Boergesson, Lennart; Hernelind, Jan; Ledesma, Alberto; Jacinto, Abel

    2012-01-01

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite 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 B right and Abaqus, have been used. The modelling performed by UPC-Cimne using Code 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

  3. The Interplay between Feedback and Buffering in Cellular Homeostasis.

    Science.gov (United States)

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

    2017-11-22

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

  4. pH variations during diafiltration due to buffer nonidealities.

    Science.gov (United States)

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

    2017-11-01

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

  5. Accelerating Science with the NERSC Burst Buffer Early User Program

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-01

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

  6. 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.

  7. On the road to improved scheduling - fitting activities to capacity

    DEFF Research Database (Denmark)

    Lindhard, Søren Munch; Wandahl, Søren

    2012-01-01

    Last Planner System has through the sounding process increased the reliability of the schedule. The sound activities are moved to a buffer and afterwards selected to the Weekly Work Plans to match capacity. Therefore, in order to maximise productivity it is essential to ensure that the sounding...... solutions to the problem are suggested and discussed. It is proposed to simplify the production by decreasing the number of trades and tasks completed at site. This can be achieved by increasing...

  8. Protein buffering in model systems and in whole human saliva.

    Directory of Open Access Journals (Sweden)

    Andreas Lamanda

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

  9. The stochastic nuclide transport model for buffer/backfill materials

    International Nuclear Information System (INIS)

    Ma Liping; Han Yongguo

    2014-01-01

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

  10. Barns Society as a Buffer Stock (Case in Nglaris Village Bener District Purworejo Regency)

    Science.gov (United States)

    Riptanti, E. W.; Qonita, A.; Suprapti

    2017-04-01

    Nglaris village is a mountainous area with most of its agricultural lands are used for growing annual crops, while only small agricultural areas are for growing rice. However, the post-harvest storage, in the form of barn society, can supply the people’s needs of rice. Article describes the function of barn society as a buffer for foods supply. Research design was exploratory research, aims to generate in-depth qualitative and contextual data. The technique applied in this research was a case study. The cost for barn society maintenance was collected from the joint venture between farmers united in the barn society group. The barn society has 20 tons capacity for unhulled rice. The farmers obtained the income from working during the harvest time and become a labour harvester to outside Nglaris or called “boro”. The farmer (field owner) gave natura wages (“bawon”). Bawon calculated based on the result of total harvested unhulled. Supply for buffer of foods in the dry season was at least 50% of the capacity barn society’s, so that it can secure the supplies of staple foods. The barn society is specifically advantageous during the dry season because each farmer could lend and should be returned within one year.

  11. An analysis of buffering in bentonite-groundwater systems

    International Nuclear Information System (INIS)

    Arthur, R.C.; Apted, M.J.

    1991-01-01

    Chemical buffering by bentonite can potentially simplify assessments of the performance of engineered barriers to radionuclide migration by decoupling near-field and far-field geochemical regimes in geologic repositories. Mass transfer calculations that account for smectite's crystalline-solution behavior demonstrate that buffering by bentonite minimizes many of the effects on fluid compositions caused by prior water-rock interactions in the far field. Buffering is manifested by simultaneous changes in the compositions of both smectite and water that are driven by concurrent irreversible dissolution of accessory minerals. Calculated equilibrium states in bentonite-groundwater systems can be validated using a regular solution model

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

    Science.gov (United States)

    Goyal, Amit; Wee, Sung-Hun

    2014-06-10

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

  13. Stacking by electroinjection with discontinuous buffers in capillary zone electrophoresis.

    Science.gov (United States)

    Shihabi, Zak K

    2002-08-01

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

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

    International Nuclear Information System (INIS)

    Neretnieks, Ivars; Liu, Loncheng; Moreno, Luis

    2010-01-01

    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. Preliminary test on filling gap behavior of the swollen buffer in the engineered barrier system. 2

    International Nuclear Information System (INIS)

    Sugita, Yutaka; Tanai, Kenji

    2003-11-01

    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, non-uniformity of the swelling of the buffer will affect the thickness of the buffer between waste package and rock mass. Long term experiments of preliminary tests that simulate 3 dimensional filling gap behavior of the swollen buffer were performed. Other test simulates the vertical emplacement option was performed, too. The test results showed that as follows; In Horizontal emplacement option, swelling of the buffer began from the surface of the buffer. Swollen buffer infiltrated into gap region there is no stress against infiltration of the buffer. Distribution of the density of the buffer was changed with time. In vertical emplacement option, there is scatter of the density of the buffer also. In center region which has the buffer initial, density was still high. Near the surface of test cell, density of the buffer was low. In this case, since the buffer was installed at the center of the test cell, density of the buffer was uniform in a circumference section. In case of swelling of the buffer with the gap, initial condition, swelling behavior and change of the density after filled the gap of the buffer should be observed. (author)

  16. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  17. 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

  18. Evaluating the effects of buffer conditions and extremolytes on thermostability of granulocyte colony-stimulating factor using high-throughput screening combined with design of experiments.

    Science.gov (United States)

    Ablinger, Elisabeth; Hellweger, Monika; Leitgeb, Stefan; Zimmer, Andreas

    2012-10-15

    In this study, we combined a high-throughput screening method, differential scanning fluorimetry (DSF), with design of experiments (DoE) methodology to evaluate the effects of several formulation components on the thermostability of granulocyte colony stimulating factor (G-CSF). First we performed a primary buffer screening where we tested thermal stability of G-CSF in different buffers, pH values and buffer concentrations. The significance of each factor and the two-way interactions between them were studied by multivariable regression analysis. pH was identified as most critical factor regarding thermal stability. The most stabilizing buffer, sodium glutamate, and sodium acetate were determined for further investigations. Second we tested the effect of 6 naturally occurring extremolytes (trehalose, sucrose, ectoine, hydroxyectoine, sorbitol, mannitol) on the thermal stability of G-CSF, using a central composite circumscribed design. At low pH (3.8) and low buffer concentration (5 mM) all extremolytes led to a significant increase in thermal stability except the addition of ectoine which resulted in a strong destabilization of G-CSF. Increasing pH and buffer concentration led to an increase in thermal stability with all investigated extremolytes. The described systematic approach allowed to create a ranking of stabilizing extremolytes at different buffer conditions. Copyright © 2012. Published by Elsevier B.V.

  19. Capacity Statement for Railways

    DEFF Research Database (Denmark)

    Landex, Alex

    2007-01-01

    The subject “Railway capacity” is a combination of the capacity consumption and how the capacity is utilized. The capacity utilization of railways can be divided into 4 core elements: The number of trains; the average speed; the heterogeneity of the operation; and the stability. This article desc...... trains. This is due to network effects in the railway system and due to the fact that more trains results in lower punctuality....

  20. The French capacity mechanism

    International Nuclear Information System (INIS)

    2014-01-01

    The French capacity mechanism has been design to ensure security of supply in the context of the energy transition. This energy transition challenges the electricity market design with several features: peak load growth, the development of renewables, demand response,... To ensure security of supply in this context, a capacity mechanism is being implemented in France. It is a market wide capacity obligation on electricity suppliers, based on market principles. Suppliers are responsible for forecasting their obligation, which corresponds to their contribution to winter peak load, and must procure enough capacity certificates to meet their obligations. Capacity certificates are granted to capacities through a certification process, which assesses their contribution to security of supply on the basis of availability commitments. This certification process is technology neutral and performance based, associated with controls and penalties in case of non compliance. Demand Side is fully integrated in the market, either through the reduction of suppliers' capacity obligation or direct participation after certification. In addition to the expected benefits in terms of security of supply, the French capacity market will foster the development of demand response. The participation of foreign capacities will require adaptations which are scheduled in a road-map, and could pave the way for further European integration of energy policies. (authors)

  1. Enhanced Control of Transient Raman Scattering Using Buffered Hydrogen in Hollow-Core Photonic Crystal Fibers

    Science.gov (United States)

    Hosseini, P.; Novoa, D.; Abdolvand, A.; Russell, P. St. J.

    2017-12-01

    Many reports on stimulated Raman scattering in mixtures of Raman-active and noble gases indicate that the addition of a dispersive buffer gas increases the phase mismatch to higher-order Stokes and anti-Stokes sidebands, resulting in a preferential conversion to the first few Stokes lines, accompanied by a significant reduction in the Raman gain due to collisions with gas molecules. Here we report that, provided the dispersion can be precisely controlled, the effective Raman gain in a gas-filled hollow-core photonic crystal fiber can actually be significantly enhanced when a buffer gas is added. This counterintuitive behavior occurs when the nonlinear coupling between the interacting fields is strong and can result in a performance similar to that of a pure Raman-active gas, but at a much lower total gas pressure, allowing competing effects such as Raman backscattering to be suppressed. We report high modal purity in all the emitted sidebands, along with anti-Stokes conversion efficiencies as high as 5% in the visible and 2% in the ultraviolet. This new class of gas-based waveguide device, which allows the nonlinear optical response to be beneficially pressure-tuned by the addition of buffer gases, may find important applications in laser science and spectroscopy.

  2. Demographic buffering: titrating the effects of birth rate and imperfect immunity on epidemic dynamics.

    Science.gov (United States)

    Morris, Sinead E; Pitzer, Virginia E; Viboud, Cécile; Metcalf, C Jessica E; Bjørnstad, Ottar N; Grenfell, Bryan T

    2015-03-06

    Host demography can alter the dynamics of infectious disease. In the case of perfectly immunizing infections, observations of strong sensitivity to demographic variation have been mechanistically explained through analysis of the susceptible-infected-recovered (SIR) model that assumes lifelong immunity following recovery from infection. When imperfect immunity is incorporated into this framework via the susceptible-infected-recovered-susceptible (SIRS) model, with individuals regaining full susceptibility following recovery, we show that rapid loss of immunity is predicted to buffer populations against the effects of demographic change. However, this buffering is contrary to the dependence on demography recently observed for partially immunizing infections such as rotavirus and respiratory syncytial virus. We show that this discrepancy arises from a key simplification embedded in the SIR(S) framework, namely that the potential for differential immune responses to repeat exposures is ignored. We explore the minimum additional immunological information that must be included to reflect the range of observed dependencies on demography. We show that including partial protection and lower transmission following primary infection is sufficient to capture more realistic reduced levels of buffering, in addition to changes in epidemic timing, across a range of partially and fully immunizing infections. Furthermore, our results identify key variables in this relationship, including R0.

  3. Analysis of Buffer Arrangements in Low and High Dimensional Networks

    Directory of Open Access Journals (Sweden)

    N. Alzeidi

    2010-12-01

    Full Text Available Virtual channels have been introduced to enhance the performance of wormhole-switched networks. They are formed by arranging the buffer space dedicated to a given physical channel into multiple parallel buffers that share the physical bandwidth on a demand driven time-multiplexed manner. The question to be answered is: given a fixed amount of finite buffer what is the optimal way to arrange it into virtual channels. There have been few studies attempting to address this issue, however, these studies have so far resorted to simulation experiments and focused on deterministic routing algorithms. In this paper we use analytical performance models to investigate the optimal arrangement of the available buffer space into multiple virtual channels when adaptive routing is used in wormhole-switched k-ary ncubes.

  4. Heat physical properties examination of buffer material. 3

    International Nuclear Information System (INIS)

    Kikuchi, Hirohito; Tanai, Kenji

    2003-12-01

    In general, the specific heat of buffer material for the thermal analysis is calculated from the thermal conductivity and the thermal diffusivity measured by using a different measurement technique and different specimen. However, these points have caused wide distribution of data. It is necessary to measure thermal characteristics with various methods at the same time for the quality assurance of data and to standardize the relational equation. Therefore, the specific heat of bentonite and bentonite/sand mixtures material was calculated by the surface-source method which was able to measure the thermal conductivity and thermal diffusivity and the same time. Experimental results are as follows; The thermal conductivity and the specific heat of buffer material increase as the water content increase. The thermal conductivity and the specific heat of buffer material change as a function of the water content of buffer material. (author)

  5. Studies of Latent Acidity and Neutral Buffered Chloroaluminate Ionic Liquids

    National Research Council Canada - National Science Library

    Osteryoung, Robert

    2000-01-01

    Studies on ionic liquids composed of aluminum chloride and 1-ethyl-3-methylimidazolium chloride were carried out, with emphasis on understanding and explaining acidity and latent acidity in "neutral buffered" melts...

  6. RESEARCH SHOWS IMPORTANCE OF RIPARIAN BUFFERS FOR AQUATIC HEALTH

    Science.gov (United States)

    Issue: Excess nitrogen from fertilizer, septic tanks, animal feedlots, and runoff from pavement can threaten aquatic ecosystem health. Riparian buffers -- the vegetated region adjacent to streams and wetlands -- are thought to be effective at intercepting and controlling excess ...

  7. The effect of buffer zone width on biodiversity

    DEFF Research Database (Denmark)

    Navntoft, Søren; Sigsgaard, Lene; Kristensen, Kristian

    2012-01-01

    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......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...... was the narrowest that consistently promoted a higher abundance or activity of arthropods within the field area (outside the hedge bottom). However, a further increase in buffer width always increased the abundance and activity of arthropods a little more....

  8. Stacking and discontinuous buffers in capillary zone electrophoresis.

    Science.gov (United States)

    Shihabi, Z K

    2000-08-01

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

  9. Trap-door-buffer Enhanced Fourier Spectrum Interferometer, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — To address NASA's need for slow- and fast-light technologies, X-wave Innovations, Inc. (XII) proposes a fiber-based ADF trap-door-buffer FTI with more powerful...

  10. Swelling of the buffer of KBS-3V deposition hole

    International Nuclear Information System (INIS)

    Lempinen, A.

    2006-12-01

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

  11. 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...

  12. 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...

  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 - 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. EnviroAtlas - Cleveland, OH - 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 - 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. Glacier melt buffering sustains river flow in the Pamir Mountains

    Science.gov (United States)

    Pohl, Eric; Andermann, Christoff; Gloaguen, Richard

    2017-04-01

    Central Asia's water resources and agricultural practices depend on snow and glacier melts in the high mountains. The Amu Darya, the main river draining the Pamir Mountains, exemplifies the resulting seasonality in stream flow. In winter, comparably low amounts of groundwater discharge feed the streams, while the bulk of precipitation is provided and stored as snow. Successive melting of snow cover and glaciers during summer releases these stored waters to the swelling rivers. Despite a strong variability in precipitation and temperatures over the entire Pamir Mountain region, river flow shows severely less variability. We investigate what processes lead to this apparent discrepancy by using a simple but robust hydrological model that we thoroughly validate with remote sensing snow cover observations, Gravity Recovery and Climate Experiment (GRACE) data, highlighting changes in total water storage, and hydrograph comparison. We find that glaciers play a paramount role by buffering extreme meteorological conditions to sustain stream flow. In a simplified scheme, low precipitation amounts in winter result in small snow stocks, compensated for by more intensive glacier melt, and vice versa. By carrying out analyses over the extensive catchment area of the Amu Darya in the high mountain domain, we highlight regional differences in the effectiveness of this mechanism. Regional influences of wind systems and associated moisture transport as well as glaciated area emerge as main factors. Modeled negative glacier mass balances between -0.38 and -0.93 m/year agree with other studies based on geodetic methods and indicate a future reduction in stream flow sustainability. This not only exacerbates the conflict potential between riparian countries downstream, but also means that extreme weather events are more likely to cause floods and droughts.

  8. Strong WW Interaction at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pelaez, Jose R

    1998-12-14

    We present a brief pedagogical introduction to the Effective Electroweak Chiral Lagrangians, which provide a model independent description of the WW interactions in the strong regime. When it is complemented with some unitarization or a dispersive approach, this formalism allows the study of the general strong scenario expected at the LHC, including resonances.

  9. A method for estimation of plasma albumin concentration from the buffering properties of whole blood

    DEFF Research Database (Denmark)

    Rees, Stephen Edward; Diemer, Tue; Kristensen, Søren Risom

    2012-01-01

    measurements of acid-base and oxygenation status. This article presents and evaluates a new method for doing so. MATERIALS AND METHODS: The mathematical method for estimating plasma albumin concentration is described. To evaluate the method at numerous albumin concentrations, blood from 19 healthy subjects......PURPOSE: Hypoalbuminemia is strongly associated with poor clinical outcome. Albumin is usually measured at the central laboratory rather than point of care, but in principle, information exists in the buffering properties of whole blood to estimate plasma albumin concentration from point of care...

  10. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.

    1995-01-01

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  11. Strong-back safety latch

    Energy Technology Data Exchange (ETDEWEB)

    DeSantis, G.N.

    1995-03-06

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch.

  12. The buffer/container experiment design and construction report

    International Nuclear Information System (INIS)

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

    1998-03-01

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

  13. 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

  14. International comparison of observation-specific spatial buffers

    DEFF Research Database (Denmark)

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

    2017-01-01

    BACKGROUND: Advancements in geographic information systems over the past two decades have increased the specificity by which an individual's neighborhood environment may be spatially defined for physical activity and health research. This study investigated how different types of street network b...... each buffering technique. The study advances knowledge by presenting consistently assessed relationships between three different network buffer types and utilitarian travel, sedentary behavior, and leisure-oriented physical activity outcomes....

  15. Current status of mechanical erosion studies of bentonite buffer

    International Nuclear Information System (INIS)

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

    2013-08-01

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

  16. Heat Capacity Analysis Report

    International Nuclear Information System (INIS)

    Findikakis, A.

    2004-01-01

    The purpose of this report is to provide heat capacity values for the host and surrounding rock layers for the waste repository at Yucca Mountain. The heat capacity representations provided by this analysis are used in unsaturated zone (UZ) flow, transport, and coupled processes numerical modeling activities, and in thermal analyses as part of the design of the repository to support the license application. Among the reports that use the heat capacity values estimated in this report are the ''Multiscale Thermohydrologic Model'' report, the ''Drift Degradation Analysis'' report, the ''Ventilation Model and Analysis Report, the Igneous Intrusion Impacts on Waste Packages and Waste Forms'' report, the ''Dike/Drift Interactions report, the Drift-Scale Coupled Processes (DST and TH Seepage) Models'' report, and the ''In-Drift Natural Convection and Condensation'' report. The specific objective of this study is to determine the rock-grain and rock-mass heat capacities for the geologic stratigraphy identified in the ''Mineralogic Model (MM3.0) Report'' (BSC 2004 [DIRS 170031], Table 1-1). This report provides estimates of the heat capacity for all stratigraphic layers except the Paleozoic, for which the mineralogic abundance data required to estimate the heat capacity are not available. The temperature range of interest in this analysis is 25 C to 325 C. This interval is broken into three separate temperature sub-intervals: 25 C to 95 C, 95 C to 114 C, and 114 C to 325 C, which correspond to the preboiling, trans-boiling, and postboiling regimes. Heat capacity is defined as the amount of energy required to raise the temperature of a unit mass of material by one degree (Nimick and Connolly 1991 [DIRS 100690], p. 5). The rock-grain heat capacity is defined as the heat capacity of the rock solids (minerals), and does not include the effect of water that exists in the rock pores. By comparison, the rock-mass heat capacity considers the heat capacity of both solids and pore

  17. Mechanisms of social buffering of fear in zebrafish.

    Science.gov (United States)

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

    2017-03-31

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

  18. Design, production and initial state of the buffer

    International Nuclear Information System (INIS)

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

    2010-12-01

    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

  19. Effects of buffer thickness on ATW blanket performances

    International Nuclear Information System (INIS)

    Yang, Won Sik

    2001-01-01

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

  20. Effects of buffer ionization in protein transition volumes.

    Science.gov (United States)

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

    2010-05-01

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

  1. 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

  2. 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.

  3. Survey of buffer management policies for delay tolerant networks

    Directory of Open Access Journals (Sweden)

    Sweta Jain

    2014-04-01

    Full Text Available Delay tolerant networks (DTN are a class of networks that are a subset of the traditional mobile ad-hoc networks. It differs from mobile ad hoc networks (MANETs in the sense that it can withstand high delays in delivering data because of frequent network partitions, limited bandwidth and storage constraints persisting in such networks. Owing to these inherent characteristics of the delay tolerant networks improving delivery ratio in such networks depends on two main factors-use of routing strategy and a good buffer management policy. Many routing protocols have been proposed in the literature for DTN. Buffer management is a very important factor in DTN because of the very limited buffer space available in DTN nodes. Although a scheduling policy in DTN determines which message has to be forwarded first, the dropping policy decides which messages are to be dropped in case of buffer overflow. This Letter presents a survey of the existing buffer management policies proposed for DTN and discusses the pros and cons of these approaches. The buffer management techniques have been classified on the basis of information used by them whether they are based on local information of messages available at the node or global information of all the messages in the network.

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

    Science.gov (United States)

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

    2012-12-01

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

  5. Prospects for OPEC capacity

    International Nuclear Information System (INIS)

    Adelman, M.A.

    1995-01-01

    OPEC capacity is not exogenous, but responds to demand. Price increases have not been caused by capacity shortages. OPEC nations find it hard to set aside even very small portions of their revenues for oil investment, despite its extreme profitability. Foreign investors face high risks. Production sharing makes their after-tax return even more unstable. (author)

  6. On a strong law of large numbers for monotone measures

    Czech Academy of Sciences Publication Activity Database

    Agahi, H.; Mohammadpour, A.; Mesiar, Radko; Ouyang, Y.

    2013-01-01

    Roč. 83, č. 4 (2013), s. 1213-1218 ISSN 0167-7152 R&D Projects: GA ČR GAP402/11/0378 Institutional support: RVO:67985556 Keywords : capacity * Choquet integral * strong law of large numbers Subject RIV: BA - General Mathematics Impact factor: 0.531, year: 2013 http://library.utia.cas.cz/separaty/2013/E/mesiar-on a strong law of large numbers for monotone measures.pdf

  7. Estimations of durability of fracture mineral buffers in the Olkiluoto bedrock

    International Nuclear Information System (INIS)

    Luukkonen, A.

    2006-12-01

    through the channel in all studied cases. This condition is unrealistic. In real, there are likely other oxygen consumers as well. With a significant probability no oxygen breakthrough can be detected at the depth of 500 metres with the studied flow rates. The potential redox buffers not taken into account are e.g. matrix diffusion and the microbiological redox processes that dominate within the soil layer and upper parts of bedrock. Cation exchange studies indicate that cation exchange has only a minor effect on the water composition running through the fracture channel. However, there is no experimental cation exchange capacity estimates available from the Olkiluoto fracture clays. (orig.)

  8. Titanium: light, strong, and white

    Science.gov (United States)

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  9. Modulation of gastric pH by a buffered soluble effervescent formulation: A possible means of improving gastric tolerability of alendronate.

    Science.gov (United States)

    Hodges, L A; Connolly, S M; Winter, J; Schmidt, T; Stevens, H N E; Hayward, M; Wilson, C G

    2012-08-01

    Gastrointestinal side-effects of alendronate (ALN) are believed to be associated with oesophageal lodging of tablets and perhaps reflux of gastric contents with alendronate under strongly acidic pH conditions. This leads to unfavourable posture restrictions when dosing. This clinical study evaluated gastric emptying and gastric pH after administration of Fosamax(®) tablets and a novel effervescent ALN formulation with a high buffering capacity. This novel formulation, EX101, was developed to potentially improve gastric tolerance. Gastric pH was monitored by nasogastric probes. Gastric emptying was determined simultaneously by scintigraphic imaging of (99m)Tc-DTPA labelled formulations. Both formulations tested rapidly cleared the oesophagus and there were no statistically significant or physiologically relevant differences in gastric emptying times. Mean pH at time to 50% gastric emptying of the radiolabel was significantly higher in EX101-treated subjects compared to those treated with Fosamax(®). At time to 90% gastric emptying of the radiolabel, mean pH values were comparable. Mucosal exposure to ALN at pH less than 3 is irritating to gastro-oesophageal tissue. Ingestion of Fosamax(®) resulted in ALN being present in the stomach at a pH below 3 within minutes. EX101 minimised the possibility of exposing the oesophagus (in case of reflux) to acidified ALN. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. (LIRNEasia) : Building Capacity in ICT Policy

    International Development Research Centre (IDRC) Digital Library (Canada)

    Learning Initiatives for Network Economies in Asia (LIRNEasia) : Building Capacity in ICT Policy. It is now generally accepted that affordable, effective telecommunication services play an integral role in development. Although there has been strong growth in connectivity in Asia, those who have benefited most are the urban ...

  11. Effects of Buffer Thickness on ATW Blanket Performance

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  12. Effects of buffer thickness on ATW blanket performance

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  13. Assessing multiregion avian benefits from strategically targeted agricultural buffers.

    Science.gov (United States)

    Evans, Kristine O; Burger, L Wes; Riffell, Sam; Smith, Mark D

    2014-08-01

    Mounting evidence of wildlife population gains from targeted conservation practices has prompted the need to develop and evaluate practices that are integrated into production agriculture systems and targeted toward specific habitat objectives. However, effectiveness of targeted conservation actions across broader landscapes is poorly understood. We evaluated multiregion, multispecies avian densities on row-crop fields with native grass field margins (i.e., buffers) as part of the first U.S. agricultural conservation practice designed to support habitat and population recovery objectives of a national wildlife conservation initiative. We coordinated breeding season point transect surveys for 6 grassland bird species on 1151 row-crop fields with and without native grass buffers (9-37 m) in 14 U.S. states (10 ecoregions) from 2006 to 2011. In most regions, breeding season densities of 5 of 6 targeted bird species were greater in the 500-m surrounding survey points centered on fields with native grass buffers than in landscapes without buffers. Relative effect sizes were greatest for Northern Bobwhite (Colinus virginianus), Dickcissel (Spiza americana), and Field Sparrow (Spizella pusilla) in the Mississippi Alluvial Valley and Eastern Tallgrass Prairie regions. Other species (e.g., Eastern Meadowlark [Sturnella magna], Grasshopper Sparrow [Ammodramus savannarum]) exhibited inconsistent relative effect sizes. Bird densities on fields with and without buffers were greatest in the Central Mixed-grass Prairie region. Our results suggest that strategic use of conservation buffers in regions with the greatest potential for relative density increases in target species will elicit greater range-wide population response than diffuse, uninformed, and broadly distributed implementation of buffers. We recommend integrating multiple conservation practices in broader agricultural landscapes to maximize conservation effectiveness for a larger suite of species. © 2014 Society for

  14. Competition increases in the face of strong regional ties

    International Nuclear Information System (INIS)

    Knoetgen, P.M.

    1987-01-01

    The current fuel market exhibits a large surplus production capacity and is strongly influenced by regional ties, with imports of fabricated fuel serving to supplement domestic production or to keep domestic vendors competitive. In the future, the market is set to become increasingly competitive, especially in Europe and the United States. (author)

  15. Carbon nanotube yarns as strong flexible conductive capacitive electrodes

    NARCIS (Netherlands)

    Liu, F.; Wagterveld, R.M.; Gebben, B.; Otto, M.J.; Biesheuvel, P.M.; Hamelers, H.V.M.

    2015-01-01

    Carbon nanotube (CNT) yarn, consisting of 23 µm diameter CNT filaments, can be used as capacitive electrodes that are long, flexible, conductive and strong, for applications in energy and electrochemical water treatment. We measure the charge storage capacity as function of salt concentration, and

  16. Vedr.: Military capacity building

    DEFF Research Database (Denmark)

    Larsen, Josefine Kühnel; Struwe, Lars Bangert

    2013-01-01

    Military capacity building has increasingly become an integral part of Danish defence. Military capacity is a new way of thinking Danish defence and poses a new set of challenges and opportunities for the Danish military and the Political leadership. On the 12th of december, PhD. Candidate Josefine...... Kühnel Larsen and researcher Lars Bangert Struwe of CMS had organized a seminar in collaboration with Royal Danish Defense Colleg and the East African Security Governance Network. The seminar focused on some of the risks involved in Military capacity building and how these risks are dealt with from...

  17. Strong economic growth driving increased electricity consumption

    International Nuclear Information System (INIS)

    Tiusanen, P.

    2000-01-01

    The Finnish economy is growing faster today than anyone dared hope only a few years ago. Growth estimates for 2000 have already had to be raised. This strong level of economic growth has been reflected in electricity consumption, which has continued to increase, despite the exceptionally warm winter. A major part of this increased electricity usage has so far been met through imports. The continued growth in electricity imports has largely been a result of the fact that the good water level situation in Sweden and Norway, together with the mild winter, has kept electricity prices exceptionally low on the Nordic electricity exchange. The short period of low temperatures seen at the end of January showed, however, that this type of temperature fluctuation, combined with the restrictions that exist in regard to transfer capacity, can serve to push Nordic exchange electricity prices to record levels. This increase in price also highlights the fact that we are approaching a situation in which capacity will be insufficient to meet demand. A truly tough winter has not been seen since the Nordic region's electricity markets were deregulated. The lesson that needs to be learnt is that Finland needs sufficient capacity of her own to meet demand even during particularly cold winters. Finland used 77.9 billion kWh of electricity last year, up 1.6% or 1.3 billion kWh on 1998. This growth was relatively evenly distributed among different user groups. This year, electricity consumption is forecast to grow by 2-3%

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

    International Nuclear Information System (INIS)

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

    2013-08-01

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

  19. Capacity at Railway Stations

    DEFF Research Database (Denmark)

    Landex, Alex

    2011-01-01

    zone(s) the possible conflicts with other trains (also in the opposite direction) are taken into account leading to more trustworthy results. Although the UIC 406 methodology proposes that the railway network should be divided into line sections when trains turn around and when the train order...... is changed, this paper recommends that the railway lines are not always be divided. In case trains turn around on open (single track) line, the capacity consumption may be too low if a railway line is divided. The same can be the case if only few trains are overtaken at an overtaking station. For dead end......Stations do have other challenges regarding capacity than open lines as it is here the traffic is dispatched. The UIC 406 capacity method that can be used to analyse the capacity consumption can be exposed in different ways at stations which may lead to different results. Therefore, stations need...

  20. MANU. Isostatic compression of buffer blocks. Small scale

    International Nuclear Information System (INIS)

    Laaksonen, R.

    2010-01-01

    The purpose of this study was to become familiar with the isostatic compression technique and to manufacture specimens to study various aspects of the manufacturing process. These included for example the effect of moisture, maximum compressive pressure, vibration, vacuum, specimen size, coating, multiple compressions and duration of load cycle on the density and other properties of bentonite specimens. Also the amount of volumetric contraction was of interest in this study together with the used mould technology. This work summarizes the tests done with isostatic compression technique during 2008. Tests were mainly carried out with MX-80 bentonite, which is a commercial product and currently the reference bentonite in the repository reference plan. Tests were made from June to November 2008 both in Finland and in Sweden. VTT made four test series in Finland. MABU Consulting Ab made two test series in Sweden. Also Posiva Oy carried out one preliminary series before this study in Finland. The test results show that there is a clear relationship between density and moisture content at all pressure levels. The calculated degree of saturation of more moist samples remained at the level of 95 -to 98 % of full saturation. It should be possible to manufacture buffer blocks with high accuracy (density, water content, degree of saturation), if similar preliminary tests are done. Tests did not support the assumption that vacuum (partial or full) in the specimen during compression increases the final density. Tests showed that pre-vibrated specimens had a slightly higher density but the difference was insignificant. Coarse raw bentonite produced the highest dry density of all sodium bentonites used. The highest dry density values were received with Minelco's Ca-bentonite, but the average water content was not extremely accurate. The following recommendations were derived from the results of this project: additional tests should be carried out to determine the relationship

  1. 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.

  2. Can Parenting Microprotections Buffer Against Adolescents' Experiences of Racial Discrimination?

    Science.gov (United States)

    Dotterer, Aryn M; James, Anthony

    2018-01-01

    Previous research highlights the importance and pervasiveness of racial discrimination for minority youth in the United States. Adolescents may experience either personal or group race-based discrimination. While past research found both forms of discrimination are harmful to well-being it is unknown whether parental microprotections, which may buffer against the negative effects of discrimination, protect against both forms of discrimination. Informed by ecological frameworks the present study examined whether parent microprotections (parental warmth/acceptance, cultural socialization, preparation for bias) buffered the effects of personal and group discrimination on adolescents' depressive symptoms. Participants were African American early adolescents (N = 129; 58% female) and their parents (90% mothers). Adolescents attended a Midwestern, Title 1, urban, public middle school and completed surveys in their homerooms and parents completed paper-pencil surveys at home, online or surveys via telephone. Multiple regression analyses were conducted to test whether adolescents' personal and group discrimination at school were related to their reports of depressive symptoms and evaluate whether parent microprotections buffered these associations. Results showed that parental microprotections moderated the effects of personal discrimination on depressive symptoms but did not buffer the effects of group discrimination. These results highlight the importance of distinguishing between personal and group discrimination. Further, additional protective factors need to be identified and tested to better understand parental actions that potentially buffer the negative effects of discrimination.

  3. Measurement of radon concentration in super-Kamiokande's buffer gas

    Science.gov (United States)

    Nakano, Y.; Sekiya, H.; Tasaka, S.; Takeuchi, Y.; Wendell, R. A.; Matsubara, M.; Nakahata, M.

    2017-09-01

    To precisely measure radon concentrations in purified air supplied to the Super-Kamiokande detector as a buffer gas, we have developed a highly sensitive radon detector with an intrinsic background as low as 0 . 33 ± 0 . 07 mBq /m3. In this article, we discuss the construction and calibration of this detector as well as results of its application to the measurement and monitoring of the buffer gas layer above Super-Kamiokande. In March 2013, the chilled activated charcoal system used to remove radon in the input buffer gas was upgraded. After this improvement, a dramatic reduction in the radon concentration of the supply gas down to 0 . 08 ± 0 . 07 mBq /m3. Additionally, the Rn concentration of the in-situ buffer gas has been measured 28 . 8 ± 1 . 7 mBq /m3 using the new radon detector. Based on these measurements we have determined that the dominant source of Rn in the buffer gas arises from contamination from the Super-Kamiokande tank itself.

  4. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning......Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...

  5. Coupled Ca2+/H+ transport by cytoplasmic buffers regulates local Ca2+ and H+ ion signaling.

    Science.gov (United States)

    Swietach, Pawel; Youm, Jae-Boum; Saegusa, Noriko; Leem, Chae-Hun; Spitzer, Kenneth W; Vaughan-Jones, Richard D

    2013-05-28

    Ca(2+) signaling regulates cell function. This is subject to modulation by H(+) ions that are universal end-products of metabolism. Due to slow diffusion and common buffers, changes in cytoplasmic [Ca(2+)] ([Ca(2+)]i) or [H(+)] ([H(+)]i) can become compartmentalized, leading potentially to complex spatial Ca(2+)/H(+) coupling. This was studied by fluorescence imaging of cardiac myocytes. An increase in [H(+)]i, produced by superfusion of acetate (salt of membrane-permeant weak acid), evoked a [Ca(2+)]i rise, independent of sarcolemmal Ca(2+) influx or release from mitochondria, sarcoplasmic reticulum, or acidic stores. Photolytic H(+) uncaging from 2-nitrobenzaldehyde also raised [Ca(2+)]i, and the yield was reduced following inhibition of glycolysis or mitochondrial respiration. H(+) uncaging into buffer mixtures in vitro demonstrated that Ca(2+) unloading from proteins, histidyl dipeptides (HDPs; e.g., carnosine), and ATP can underlie the H(+)-evoked [Ca(2+)]i rise. Raising [H(+)]i tonically at one end of a myocyte evoked a local [Ca(2+)]i rise in the acidic microdomain, which did not dissipate. The result is consistent with uphill Ca(2+) transport into the acidic zone via Ca(2+)/H(+) exchange on diffusible HDPs and ATP molecules, energized by the [H(+)]i gradient. Ca(2+) recruitment to a localized acid microdomain was greatly reduced during intracellular Mg(2+) overload or by ATP depletion, maneuvers that reduce the Ca(2+)-carrying capacity of HDPs. Cytoplasmic HDPs and ATP underlie spatial Ca(2+)/H(+) coupling in the cardiac myocyte by providing ion exchange and transport on common buffer sites. Given the abundance of cellular HDPs and ATP, spatial Ca(2+)/H(+) coupling is likely to be of general importance in cell signaling.

  6. Thermal buffering of concrete by seaweeds during a prolonged summer heatwave

    Science.gov (United States)

    Naylor, Larissa; Coombes, Martin

    2014-05-01

    Hard coastal infrastructure is subject to aggressive environmental conditions, including a suite of weathering processes in the intertidal zone. These processes, along with waves, lead to costly deterioration of coastal structures. Existing methods (e.g. coatings, less porous concrete) to reduce the risk of concrete deterioration rapidly lose their effectiveness in the intertidal zone. Additionally, a changing climate will lead to increased frequency of storms, higher sea level and higher extreme temperatures - and therefore, pose an increased risk of deterioration. Might there be a biogenic solution? New research (Coombes et al. 2013) has shown that fucoid seaweeds reduce microclimatic extremes and variability under normal summer conditions. The results presented here supplement these findings in two ways. First, they demonstrate that fucoid seaweeds act as a thermal buffer during a prolonged summer heatwave in Britain (July 2013). Over 36 days of continuous monitoring at two sites in Cornwall, UK, 19 of which were during the official heatwave, there were statistically significant differences (p = 0.000) in the maximum temperatures between thick seaweed (7.5 - 9.5 cm thickness) and thin seaweed (2 - 2.5 cm thickness) plots. Maximum temperatures reached 22°C and 33°C, for thick seaweed and thin seaweed plots, respectively. Variations in maximum temperatures between the two sites appear to be related to aspect. Second, the significantly different maximum temperature results between plots also demonstrate that seaweed thickness is an important factor influencing thermal buffering capacity. These data clearly demonstrate that fucoid seaweeds buffer concrete seawalls against extreme temperature fluxes during a heatwave, probably limiting the efficiency of deteriorative processes such as thermal expansion and contraction and salt crystallisation.

  7. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  8. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  9. Eco-buffers: A high density agroforestry design using native species

    Science.gov (United States)

    William Schroeder

    2012-01-01

    This study showed that Eco-Buffers are characterized by rapid establishment and superior survival when compared to single species buffers. Height of green ash (Fraxinus pennsylvanica Marsh. var. subintegerrima (Vahl.) Fern.) after eight growing seasons averaged 415 cm when growing in an Eco-Buffer compared to 333cm in the single species buffer. Site capture in the Eco-...

  10. Using soil surveys to target riparian buffers in the Chesapeake Bay watershed

    Science.gov (United States)

    Michael G. Dosskey

    2008-01-01

    The efficacy of vegetative buffers for improving water quality could be enhanced by distinguishing differences in buffer capability across watersheds and accounting for them in buffer planning. A soil survey-based method was applied to riparian areas in the Chesapeake Bay watershed. The method is based on soil attributes that are important in determining buffer...

  11. Designing bioenergy crop buffers to mitigate nitrous oxide emissions and water quality impacts from agriculture

    Science.gov (United States)

    Gopalakrishnan, G.; Negri, C. M.

    2010-12-01

    There is a strong societal need to evaluate and understand the environmental aspects of bioenergy production, especially due to the significant increases in production mandated by many countries, including the United States. Bioenergy is a land-based renewable resource and increases in production are likely to result in large-scale conversion of land from current uses to bioenergy crop production; potentially causing increases in the prices of food, land and agricultural commodities as well as disruption of ecosystems. Current research on the environmental sustainability of bioenergy has largely focused on the potential of bioenergy crops to sequester carbon and mitigate greenhouse gas (GHG) emissions and possible impacts on water quality and quantity. A key assumption in these studies is that bioenergy crops will be grown in a manner similar to current agricultural crops such as corn and hence would affect the environment similarly. This study presents a systems approach where the agricultural, energy and environmental sectors are considered as components of a single system, and bioenergy crops are used to design multi-functional agricultural landscapes that meet society’s requirements for food, energy and environmental protection. We evaluate the production of bioenergy crop buffers on marginal land and using degraded water and discuss the potential for growing cellulosic bioenergy crops such as miscanthus and switchgrass in optimized systems such that (1) marginal land is brought into productive use; (2) impaired water is used to boost yields (3); clean freshwater is left for other uses that require higher water quality; and (4) feedstock diversification is achieved that helps ecological sustainability, biodiversity, and economic opportunities for farmers. The process-based biogeochemical model DNDC was used to simulate crop yield, nitrous oxide production and nitrate concentrations in groundwater when bioenergy crops were grown in buffer strips adjacent to

  12. Managing diminished irrigation capacity with preseason irrigation and plant density for corn production

    Science.gov (United States)

    Many of the irrigation systems today in the U.S. Central Great Plains no longer have the capacity to match peak irrigation needs during the summer and must rely on soil water reserves to buffer the crop from water stress. Considerable research was conducted on preseason irrigation in the U.S. Great ...

  13. The buffering effect of relationship satisfaction on emotional distress in couples

    Directory of Open Access Journals (Sweden)

    Røsand Gun-Mette B

    2012-01-01

    Full Text Available Abstract Background Marital distress and depression frequently co-occur, and partnership quality is associated with depressive symptoms and mental disorders in both men and women. One aim of this study was to investigate the contribution of a set of risk factors for emotional distress among men and women in couples, with a special focus on satisfaction with partner relationship. The most important aim was to investigate the extent to which high relationship satisfaction in couples acts as a buffer against stressful events. Methods Pregnant women and their husbands (n = 62,956 couples enrolled in the Norwegian Mother and Child Cohort Study completed a questionnaire with questions about emotional distress, relationship satisfaction, and other risk factors. Twelve potential risk factors were included in the analyses, including relationship satisfaction, demographic characteristics, and somatic diseases in men and women. Associations between the predictor variables and emotional distress were estimated by multiple linear regression analysis. Cross-spousal effects, in which data reported by one of the spouses predicted emotional distress in the other, were also investigated. Possible interaction effects between certain risk factors and self-reported and partner's relationship satisfaction were tested and further explored with regression analyses in subsamples stratified by relationship satisfaction scores. Results The unique effects of relationship satisfaction were of similar sizes for both men and women: substantial for self-reported (β = -0.23 and β = -0.28, respectively and weak for partner-reported satisfaction (β = -0.04 and β = -0.02, respectively. Other relatively strong risk factors were somatic disease, first-time motherhood, and unemployment. Self-reported as well as partner-reported relationship satisfaction appeared to strongly buffer the effects of a number of stressors. Conclusions Partner relationship dissatisfaction is strongly

  14. Buffer thermal energy storage for an air Brayton solar engine

    Science.gov (United States)

    Strumpf, H. J.; Barr, K. P.

    1981-01-01

    The application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine was studied. To demonstrate the effect of buffer thermal energy storage on engine operation, a computer program was written which models the recuperator, receiver, and thermal storage device as finite-element thermal masses. Actual operating or predicted performance data are used for all components, including the rotating equipment. Based on insolation input and a specified control scheme, the program predicts the Brayton engine operation, including flows, temperatures, and pressures for the various components, along with the engine output power. An economic parametric study indicates that the economic viability of buffer thermal energy storage is largely a function of the achievable engine life.

  15. 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 building products to improve indoor air quality and to save energy. Of interest therefore is to establish a unit to appraise this quality of building products and to investigate the importance of moisture buffering when it is considered in whole building hygrothermal simulation. This paper will illustrate...... both. A new test method specifies a protocol for determination of what has recently been termed the Moisture Buffer Value (MBV) of building products. The paper presents the definition of MBV and introduces a test protocol which has been proposed for its experimental determination. The MBV is primarily...

  16. On the risk of liquefaction of buffer and backfill

    International Nuclear Information System (INIS)

    Pusch, R.

    2000-10-01

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

  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...... buffering and 2) Kir4.1 enacts spatial buffering of K(+) during but not after neuronal activity....

  18. Clay colloid formation and release from MX-80 buffer

    International Nuclear Information System (INIS)

    Pusch, R.

    1999-12-01

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

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

    International Nuclear Information System (INIS)

    Boergesson, Lennart; Sanden, Torbjoern

    2006-09-01

    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

  20. Effects of buffer layer on the structural and electrical properties of InAsSb epilayers grown on GaAs(001)

    International Nuclear Information System (INIS)

    Jayavel, P.; Nakamura, S.; Koyama, T.; Hayakawa, Y.

    2006-01-01

    InAsSb ternary epilayers with arsenic composition of 0.5 have been grown on GaAs(001) substrates. Linear-graded and step-graded InAsSb buffer layers with an InSb layer have been used to relax lattice mismatch between the epilayer and substrate. X-ray diffraction results of the epilayers indicate that an enhancement in the peak intensity of the buffer layer samples is due to improved crystalline quality of the epilayers. We find that the growth technique of the buffer layer strongly influences the surface morphology and roughness of the epilayer. Hall effect measurements of the step-graded buffer layer samples show an order of magnitude higher electron mobility than the direct and linear-graded buffer layer samples. These results demonstrate that high crystalline quality and electron mobility of the InAs 0.5 Sb 0.5 ternary epilayers can be achieved by using the step-graded InAsSb buffer layers. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Modification of gel architecture and TBE/TAE buffer composition to minimize heating during agarose gel electrophoresis.

    Science.gov (United States)

    Sanderson, Brian A; Araki, Naoko; Lilley, Jennifer L; Guerrero, Gilberto; Lewis, L Kevin

    2014-06-01

    Agarose gel electrophoresis of DNA and RNA is routinely performed using buffers containing either Tris, acetate, and EDTA (TAE) or Tris, borate, and EDTA (TBE). Gels are run at a low, constant voltage (∼10 V/cm) to minimize current and asymmetric heating effects, which can induce band artifacts and poor resolution. In this study, alterations of gel structure and conductive media composition were analyzed to identify factors causing higher electrical currents during horizontal slab gel electrophoresis. Current was reduced when thinner gels and smaller chamber buffer volumes were used, but was not influenced by agarose concentration or the presence of ethidium bromide. Current was strongly dependent on the amount and type of EDTA used and on the concentrations of the major acid-base components of each buffer. Interestingly, resolution and the mobilities of circular versus linear plasmid DNAs were also affected by the chemical form and amount of EDTA. With appropriate modifications to gel structure and buffer constituents, electrophoresis could be performed at high voltages (20-25 V/cm), reducing run times by up to 3-fold. The most striking improvements were observed with small DNAs and RNAs (10-100 bp): high voltages and short run times produced sharper bands and higher resolution. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Buffered 1% Lidocaine With Epinephrine Is as Effective as Non-Buffered 2% Lidocaine With Epinephrine for Mandibular Nerve Block.

    Science.gov (United States)

    Warren, Victor T; Fisher, Anson G; Rivera, Eric M; Saha, Pooja T; Turner, Blake; Reside, Glenn; Phillips, Ceib; White, Raymond P

    2017-07-01

    To assess outcomes for pulpal anesthesia and pain on injection for buffered 1% lidocaine with 1:100,000 epinephrine (EPI) versus non-buffered 2% lidocaine with 1:100,000 EPI. In a randomized cross-over trial approved by the institutional review board, buffered 1% lidocaine with 1:100,000 EPI was compared with non-buffered 2% lidocaine with 1:100,000 EPI. After mandibular nerve block with buffered lidocaine 40 mg or non-buffered lidocaine 80 mg, patients reported responses at the mandibular first molar and canine after cold and electrical pulp testing (EPT). Patients also reported pain on injection with a 10-point Likert-type scale. Teeth were tested before nerve block and at 30-minute intervals until a positive response returned. Two weeks later, patients were tested with the alternate drug combinations. The same outcomes were assessed. Predictor variables were alternate drug formulations. Outcome variables were patients' responses to cold and EPT stimulation of the mandibular first molar and canine and pain on injection. An assessment of treatment difference was performed using Wilcoxon rank-sum tests with Proc NPAR1WAY (SAS 9.3, SAS Institute, Cary, NC). Significance was set at a P value less than .05. Fifty-seven percent of patients were women and 43% were men. Seventy percent were Caucasian, 17% were African American, and 13% had another ethnicity. Median age was 25 years (interquartile range [IQR], 21-26 yr) and median body weight was 140 lbs (IQR, 120-155 lbs). After the cold test and EPT, the time to sensation return for the molar or canine was not statistically different between the 2 drug formulations. Patients reported significantly lower pain scores with the buffered versus non-buffered drug (P lidocaine with EPI can produce similar clinical outcomes for duration of pulpal anesthesia as non-buffered 2% lidocaine with EPI and lower pain on injections, which are a potential benefit to patients. Copyright © 2017 American Association of Oral and

  3. A two-stage stochastic rule-based model to determine pre-assembly buffer content

    Science.gov (United States)

    Gunay, Elif Elcin; Kula, Ufuk

    2018-01-01

    This study considers instant decision-making needs of the automobile manufactures for resequencing vehicles before final assembly (FA). We propose a rule-based two-stage stochastic model to determine the number of spare vehicles that should be kept in the pre-assembly buffer to restore the altered sequence due to paint defects and upstream department constraints. First stage of the model decides the spare vehicle quantities, where the second stage model recovers the scrambled sequence respect to pre-defined rules. The problem is solved by sample average approximation (SAA) algorithm. We conduct a numerical study to compare the solutions of heuristic model with optimal ones and provide following insights: (i) as the mismatch between paint entrance and scheduled sequence decreases, the rule-based heuristic model recovers the scrambled sequence as good as the optimal resequencing model, (ii) the rule-based model is more sensitive to the mismatch between the paint entrance and scheduled sequences for recovering the scrambled sequence, (iii) as the defect rate increases, the difference in recovery effectiveness between rule-based heuristic and optimal solutions increases, (iv) as buffer capacity increases, the recovery effectiveness of the optimization model outperforms heuristic model, (v) as expected the rule-based model holds more inventory than the optimization model.

  4. Regional zooplankton biodiversity provides limited buffering of pond ecosystems against climate change.

    Science.gov (United States)

    Thompson, Patrick L; Shurin, Jonathan B

    2012-01-01

    1. Climate change and other human-driven environmental perturbations are causing reductions in biodiversity and impacting the functioning of ecosystems on a global scale. Metacommunity theory suggests that ecosystem connectivity may reduce the magnitude of these impacts if the regional species pool contains functionally redundant species that differ in their environmental tolerances. Dispersal may increase the resistance of local ecosystems to environmental stress by providing regional species with traits adapted to novel conditions. 2. We tested this theory by subjecting freshwater zooplankton communities in mesocosms that were either connected to or isolated from the larger regional species pool to a factorial manipulation of experimental warming and increased salinity. 3. Compensation by regional taxa depended on the source of stress. Warming tolerant regional taxa partially compensated for reductions in heat sensitive local taxa but similar compensation did not occur under increased salinity. 4. Dispersal-mediated species invasions dampened the effects of warming on summer net ecosystem productivity. However, this buffering effect did not occur in the fall or for periphyton growth, the only other ecosystem function affected by the stress treatments. 5. The results indicate that regional biodiversity can provide insurance in a dynamic environment but that the buffering capacity is limited to some ecosystem processes and sources of stress. Maintaining regional biodiversity and habitat connectivity may therefore provide some limited insurance for local ecosystems in changing environments, but is unable to impart resistance against all sources of environmental stress. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

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

    KAUST Repository

    Shaqfeh, Mohammad

    2016-05-25

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

  6. Exposure to buffer solution alters tendon hydration and mechanics.

    Science.gov (United States)

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

    2017-08-16

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

  7. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...

  8. Strong interaction at finite temperature

    Indian Academy of Sciences (India)

    Abstract. We review two methods discussed in the literature to determine the effective parameters of strongly interacting particles as they move through a heat bath. The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules ...

  9. Strong-strong beam-beam simulation on parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji

    2004-08-02

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.

  10. Strong-strong beam-beam simulation on parallel computer

    International Nuclear Information System (INIS)

    Qiang, Ji

    2004-01-01

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders

  11. Aacsfi-PSC. Advanced accelerator concepts for strong field interaction simulated with the Plasma-Simulation-Code

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, Hartmut [Munich Univ. (Germany). Chair for Computational and Plasma Physics

    2016-11-01

    Since the installation of SuperMUC phase 2 the 9216 nodes of phase 1 are more easily available for large scale runs allowing for the thin foil and AWAKE simulations. Besides phase 2 could be used in parallel for high throughput of the ion acceleration simulations. Challenging to our project were the full-volume checkpoints required by PIC that strained the I/O-subsystem of SuperMUC to its limits. New approaches considered for the next generation system, like burst buffers could overcome this bottleneck. Additionally, as the FDTD solver in PIC is strongly bandwidth bound, PSC will benefit profoundly from high-bandwidth memory (HBM) that most likely will be available in future HPC machines. This will be of great advantage as in 2018 phase II of AWAKE should begin, with a longer plasma channel further increasing the need for additional computing resources. Last but not least, it is expected that our methods used in plasma physics (many body interaction with radiation) will be more and more adapted for medical diagnostics and treatments. For this research field we expect centimeter sized volumes with necessary resolutions of tens of micro meters resulting in boxes of >10{sup 12} voxels (100-200 TB) on a regular basis. In consequence the demand for computing time and especially for data storage and data handling capacities will also increase significantly.

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    for 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 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....

  13. Thermo-Hydraulic Modelling of Buffer and Backfill

    International Nuclear Information System (INIS)

    Pintado, X.; Rautioaho, E.

    2013-09-01

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

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

    International Nuclear Information System (INIS)

    Naoi, Yutaka; Komine, Hideo; Yasuhara, Kazuya; Murakami, Satoshi; Momose, Kazuo; Sakagami, Takeharu

    2005-01-01

    A high level radioactive waste disposal facility may be built on a coastal area. Therefore, it is important to investigate the influence of seawater on bentonite buffer material. The purpose of this study is to investigate the influence of seawater on the swelling pressure and swelling deformation characteristics of five typical kinds of bentonites. This experimental work clarified the relations between the influence grade of seawater and compaction density, type of exchangeable-cation, montmorillonite content of the bentonite, and vertical pressure condition. Based on experimental results, a specification for the buffer material which can overcome the influence of seawater was defined. (author)

  15. Impact of Burst Buffer Architectures on Application Portability

    Energy Technology Data Exchange (ETDEWEB)

    Harms, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Oral, H. Sarp [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Science; Atchley, Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Science; Vazhkudai, Sudharshan S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Science

    2016-09-30

    The Oak Ridge and Argonne Leadership Computing Facilities are both receiving new systems under the Collaboration of Oak Ridge, Argonne, and Livermore (CORAL) program. Because they are both part of the INCITE program, applications need to be portable between these two facilities. However, the Summit and Aurora systems will be vastly different architectures, including their I/O subsystems. While both systems will have POSIX-compliant parallel file systems, their Burst Buffer technologies will be different. This difference may pose challenges to application portability between facilities. Application developers need to pay attention to specific burst buffer implementations to maximize code portability.

  16. SDRAM-based packet buffer model for high speed switches

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Ruepp, Sarah Renée; Berger, Michael Stübert

    2011-01-01

    This article investigates the how the performance of SDRAM based packet buffering systems for high performance switches can be simulated using OPNET. In order to include the access pattern dependent performance of SDRAM modules in simulations, a custom SDRAM model is implemented in OPNET Modeller...... based on the specifications of a real-life DDR3-SDRAM chip. Based on this model the performance of different schemes for optimizing the performance of such a packet buffer can be evaluated. The purpose of this study is to find efficient schemes for memory mapping of the packet queues and I/O traffic...

  17. Evidence for the buffer zone in a plasma accelerator

    International Nuclear Information System (INIS)

    Thomas, K.A.; Clothiaux, E.J.

    1991-01-01

    The existence of an absorbing layer, or buffer zone, of weakly ionized gas between the rear of the projectile and the front of the plasma arc armature in a plasma accelerator has been postulated. In the studies reported here a technique for finding the position of the projectile as a function of time is given and compared to the plasma armature position as determined by inductive probes. Analyses of these signals provide the basis for a description of the in-bore motion of the projectile with respect to the plasma arc armature. The experimental evidence appears to support the existence of a buffer zone

  18. Biomechanical Response and Behavior of Users under Emergency Buffer Crash

    Directory of Open Access Journals (Sweden)

    R. Miralbes

    2013-01-01

    Full Text Available This paper aims to study the biomechanical effects on elevator users and the injuries sustained should an elevator crash happen. The analysis will focus on buffer impact, signaling that the earlier mentioned buffer is usually located at the bottom of the pit. In order to carry out this analysis, a numerical technique based on finite element method will be used, while elevator users will be simulated by means of automotive dummies. Two crash factors will be studied, namely, location of dummy and fall velocity. The analysis criteria will be damages sustained by the dummy, based on biomechanical index such as HIC, CSI, forces, and accelerations.

  19. NORDTEST Project on Moisture Buffer Value of Materials

    DEFF Research Database (Denmark)

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

    2005-01-01

    being completed, to develop a definition, and to declare it in the form of a NORDTEST method. Apart from the definition of the term Moisture Buffer Value, the project also declares a test protocol which expresses how materials should be tested. Finally as a part of the project, some Round Robin Tests...... have been carried out on various typical building materials. The paper gives an account on the definition of the Moisture Buffer Value, it outlines the content of the test protocol, and it gives some examples of results from the Round Robin Tests....

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

    Science.gov (United States)

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

    2017-10-19

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

  1. Impact of buffer gas quenching on the 1S0 → 1P1 ground-state atomic transition in nobelium

    NARCIS (Netherlands)

    Chhetri, Premaditya; Ackermann, Dieter; Backe, Hartmut; Block, Michael; Cheal, Bradley; Düllmann, Christoph Emanuel; Even, Julia; Ferrer, Rafael; Giacoppo, Francesca; Götz, Stefan; Heßberger, Fritz Peter; Kaleja, Oliver; Khuyagbaatar, Jadambaa; Kunz, Peter; Laatiaoui, Mustapha; Lautenschläger, Felix; Lauth, Werner; Ramirez, Enrique Minaya; Mistry, Andrew Kishor; Raeder, Sebastian; Wraith, Calvin; Walther, Thomas; Yakushev, Alexander

    2017-01-01

    Using the sensitive Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique an optical transition in neutral nobelium (No, Z = 102) was identified. A remnant signal when delaying the ionizing laser indicated the influence of a strong buffer gas induced de-excitation of the optically

  2. Is montmorillonite-rich clay of MX-80 type the ideal buffer for isolation of HLW?

    International Nuclear Information System (INIS)

    Pusch, R.

    1999-12-01

    Four commercial clays, saponite, mixed-layer smectite-mica, kaolinite, and palygorskite, have been examined as possible alternatives to MX-80 buffer. General estimates based on the microstructural constitution and hydration potential as well as actual laboratory testing show that except for normally graded kaolinite, they would all serve acceptably in a repository. MX-80 is, however, superior with respect to hydraulic conductivity and retardation of diffusive transport of relevant cations and, like saponite and palygorskite, it has a high swelling pressure, that may in fact be too high. The mixed-layer clay is less but sufficiently expandable and is concluded to have better thermal and rheological properties as well as gas release capacity. It is hence the number one competitor to MX-80

  3. Is montmorillonite-rich clay of MX-80 type the ideal buffer for isolation of HLW?

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-01

    Four commercial clays, saponite, mixed-layer smectite-mica, kaolinite, and palygorskite, have been examined as possible alternatives to MX-80 buffer. General estimates based on the microstructural constitution and hydration potential as well as actual laboratory testing show that except for normally graded kaolinite, they would all serve acceptably in a repository. MX-80 is, however, superior with respect to hydraulic conductivity and retardation of diffusive transport of relevant cations and, like saponite and palygorskite, it has a high swelling pressure, that may in fact be too high. The mixed-layer clay is less but sufficiently expandable and is concluded to have better thermal and rheological properties as well as gas release capacity. It is hence the number one competitor to MX-80.

  4. Determination of tropane alkaloids by heart cutting reversed phase - Strong cation exchange two dimensional liquid chromatography.

    Science.gov (United States)

    Long, Zhen; Zhang, Yanhai; Gamache, Paul; Guo, Zhimou; Steiner, Frank; Du, Nana; Liu, Xiaoda; Jin, Yan; Liu, Xingguo; Liu, Lvye

    2018-01-01

    Current Chinese Pharmacopoeia (ChP) standards apply liquid extraction combined with one dimensional liquid chromatography (1DLC) method for determining alkaloids in herbal medicines. The complex pretreatments lead to a low analytical efficiency and possible component loss. In this study, a heart cutting reversed phase - strong cation exchange two dimensional liquid chromatography (RP - SCX 2DLC) approach was optimized for simultaneously quantifying tropane alkaloids (anisodine, scopolamine and hyoscyamine) in herbal medicines and herbal medicine tablets without further treatment of the filtered extract. The chromatographic conditions were systematically optimized in terms of column type, mobile phase composition and flow rate. To improve peak capacity and obtain symmetric peak shape of alkaloids, a polar group embedded C18 column combined with chaotropic salts was used in the first dimension. To remove the disturbance of non-alkaloids, achieve unique selectivity and acquire symmetric peak shape of alkaloids, an SCX column combined with phosphate buffer was used in the second dimension. Method validation was performed in terms of linearity, precision (0.54-0.82%), recovery (94.1-105.2%), limit of detection (LOD) and limit of quantification (LOQ) of the three analytes varied between 0.067-0.115mgL -1 and 0.195-0.268mgL -1 , respectively. The method demonstrated superiority over 1DLC method in respect of resolution (less alkaloid co-eluted), sample preparation (no pretreatment procedure) and transfer rate (minimum component loss). The optimized RP - SCX 2DLC approach was subsequently applied to quantify target alkaloids in five herbal medicines and herbal medicine tablets from three different manufactures. The results demonstrated that the developed heart cutting RP - SCX 2DLC approach represented a new, strategically significant methodology for the quality evaluation of tropane alkaloid in related herbal medicines that involve complex chemical matrix. Copyright

  5. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  7. 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

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

    International Nuclear Information System (INIS)

    Pusch, Roland

    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

  9. Weather and road capacity

    DEFF Research Database (Denmark)

    Jensen, Thomas Christian

    2014-01-01

    The paper presents estimations of the effect of bad weather on the observed speed on a Danish highway section; Køge Bugt Motorvejen. The paper concludes that weather, primarily precipitation and snow, has a clear negative effect on speed when the road is not in hypercongestion mode. Furthermore......, the capacity of the highway seems to be reduced in bad weather and there are indications that travel time variability is also increased, at least in free-flow conditions. Heavy precipitation reduces speed and capacity by around 5-8%, whereas snow primarily reduces capacity. Other weather variables......-parametrically against traffic density and in step 2 the residuals from step 1 are regressed linearly against the weather variables. The choice of a non-parametric method is made to avoid constricting ties from a parametric specification and because the focus here is not on the relationship between traffic flow...

  10. Dual capacity reciprocating compressor

    Science.gov (United States)

    Wolfe, Robert W.

    1984-01-01

    A multi-cylinder compressor 10 particularly useful in connection with northern climate heat pumps and in which different capacities are available in accordance with reversing motor 16 rotation is provided with an eccentric cam 38 on a crank pin 34 under a fraction of the connecting rods, and arranged for rotation upon the crank pin between opposite positions 180.degree. apart so that with cam rotation on the crank pin such that the crank throw is at its normal maximum value all pistons pump at full capacity, and with rotation of the crank shaft in the opposite direction the cam moves to a circumferential position on the crank pin such that the overall crank throw is zero. Pistons 24 whose connecting rods 30 ride on a crank pin 36 without a cam pump their normal rate with either crank rotational direction. Thus a small clearance volume is provided for any piston that moves when in either capacity mode of operation.

  11. Geothermal Plant Capacity Factors

    Energy Technology Data Exchange (ETDEWEB)

    Greg Mines; Jay Nathwani; Christopher Richard; Hillary Hanson; Rachel Wood

    2015-01-01

    The capacity factors recently provided by the Energy Information Administration (EIA) indicated this plant performance metric had declined for geothermal power plants since 2008. Though capacity factor is a term commonly used by geothermal stakeholders to express the ability of a plant to produce power, it is a term frequently misunderstood and in some instances incorrectly used. In this paper we discuss how this capacity factor is defined and utilized by the EIA, including discussion on the information that the EIA requests from operations in their 923 and 860 forms that are submitted both monthly and annually by geothermal operators. A discussion is also provided regarding the entities utilizing the information in the EIA reports, and how those entities can misinterpret the data being supplied by the operators. The intent of the paper is to inform the facility operators as the importance of the accuracy of the data that they provide, and the implications of not providing the correct information.

  12. Macrophyte and pH buffering updates to the Klamath River water-quality model upstream of Keno Dam, Oregon

    Science.gov (United States)

    Sullivan, Annett B.; Rounds, Stewart A.; Asbill-Case, Jessica R.; Deas, Michael L.

    2013-01-01

    A hydrodynamic, water temperature, and water-quality model of the Link River to Keno Dam reach of the upper Klamath River was updated to account for macrophytes and enhanced pH buffering from dissolved organic matter, ammonia, and orthophosphorus. Macrophytes had been observed in this reach by field personnel, so macrophyte field data were collected in summer and fall (June-October) 2011 to provide a dataset to guide the inclusion of macrophytes in the model. Three types of macrophytes were most common: pondweed (Potamogeton species), coontail (Ceratophyllum demersum), and common waterweed (Elodea canadensis). Pondweed was found throughout the Link River to Keno Dam reach in early summer with densities declining by mid-summer and fall. Coontail and common waterweed were more common in the lower reach near Keno Dam and were at highest density in summer. All species were most dense in shallow water (less than 2 meters deep) near shore. The highest estimated dry weight biomass for any sample during the study was 202 grams per square meter for coontail in August. Guided by field results, three macrophyte groups were incorporated into the CE-QUAL-W2 model for calendar years 2006-09. The CE-QUAL-W2 model code was adjusted to allow the user to initialize macrophyte populations spatially across the model grid. The default CE-QUAL-W2 model includes pH buffering by carbonates, but does not include pH buffering by organic matter, ammonia, or orthophosphorus. These three constituents, especially dissolved organic matter, are present in the upper Klamath River at concentrations that provide substantial pH buffering capacity. In this study, CE-QUAL-W2 was updated to include this enhanced buffering capacity in the simulation of pH. Acid dissociation constants for ammonium and phosphoric acid were taken from the literature. For dissolved organic matter, the number of organic acid groups and each group's acid dissociation constant (Ka) and site density (moles of sites per mole of

  13. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando

    2015-01-01

    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  14. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo

    2012-01-01

    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  15. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando

    2013-01-01

    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  16. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  17. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  18. Value for railway capacity

    DEFF Research Database (Denmark)

    Sameni, Melody Khadem; Preston, John M.

    2012-01-01

    to analyze the efficiency of operators in transforming inputs of allocated capacity of infrastructure and franchise payments into valuable passenger service outputs while avoiding delays. By addressing operational and economic aspects of capacity utilization simultaneously, the paper deviates from existing...... DEA work on the economic efficiency of railways by considering a new combination of input-output that also incorporates quality of service. The constant and variable returns to scale models are applied to the case study of franchised passenger operators in Great Britain. The follow-up Tobit regression...

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

    Science.gov (United States)

    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 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. PMID:22761833

  20. Development of preventative streamside landslide buffers on managed timberlands

    Science.gov (United States)

    Jason S. Woodward; Matthew R. House; David W. Lamphear

    2017-01-01

    Shallow streamside landslides are a principle source of sediment on managed timberlands in northern California. Using an adaptive management process, LiDAR, and a detailed field-based landslide inventory, Green Diamond Resource Company (GDRCo) has redefined the interim preventative landslide tree-retention buffers it applies to steep streamside slopes along...