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Accumulation Process (accumulation + process)
Selected AbstractsAccumulation Process of High-Z Impurity in Toroidal Rotating Tokamak PlasmaCONTRIBUTIONS TO PLASMA PHYSICS, Issue 3-5 2010K. Hoshino Abstract The accumulation process of high-Z impurity in toroidal rotating tokamak plasma is investigated. A new inward pinch of high-Z impurity due to the ionization/recombination processes is derived using an analytic model. This inward pinch is driven by the large deviation of a drift orbit from a magnetic surface and the resultant variation of the charge state along the drift orbit. The pinch velocity increases with increasing toroidal rotation speed in both the co-direction and the ctr-direction. The inward pinch expected by the analytic model is really observed in the numerical simulation using the IMPGYRO code (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A Systematic Analysis of Coal Accumulation ProcessACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2008CHENG Aiguo Abstract: Formation of coal seam and coal-rich zone is an integrated result of a series of factors in coal accumulation process. The coal accumulation system is an architectural aggregation of coal accumulation factors. It can be classified into 4 levels: the global coal accumulation super-system, the coal accumulation domain mega-system, the coal accumulation basin system, and the coal seam or coal seam set sub-system. The coal accumulation process is an open, dynamic, and grey system, and is meanwhile a system with such natures as aggregation, relevance, entirety, purpose-orientated, hierarchy, and environment adaptability. In this paper, we take coal accumulation process as a system to study origin of coal seam and coal-rich zone; and we will discuss a methodology of the systematic analysis of coal accumulation process. As an example, the Ordos coal basin was investigated to elucidate the application of the method of the coal accumulation system analysis. [source] Acute toxicity and bioaccumulation of pesticide Diazinon in red tilapia (Oreochromis niloticus x Mossambicus albina)ENVIRONMENTAL TOXICOLOGY, Issue 4 2002Jaime A. Palacio Abstract Young red tilapias were exposed for 96 h to each one of 6 concentrations of the pesticide Diazinon in order to determine the pesticide's acute toxicity level. After the ascertaining the lethal concentration (LC50) at 96 h, a level 10 times lower was selected for the bioaccumulation study of the pesticide in male and female specimens exposed for 9 days. The elimination process was carried out for 10 days beginning right after the conclusion of the accumulation process. Analytical procedures were developed and used for the studies of acute toxicity and bioaccumulation of Diazinon in red tilapia. A lethal concentration [LC50 (96 h)] of 3.85 mg/L was found, and steady-state accumulation, at a concentration of 28.45 mg/kg, was reached at 7.72 days. In the elimination process a concentration of 0.29 mg/kg was found in tilapia tissue by the sixth day after the fish were moved to clean water, and it continued to decrease quickly toward nondetectable levels. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 334,340, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10063 [source] Determining toxicity of lead and zinc runoff in soils: Salinity effects on metal partitioning and on phytotoxicityENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2003Daryl P. Stevens Abstract When assessingcationic metal toxicity in soils, metals are often added to soil as the chloride, nitrate, or sulfate salts. In many studies, the effects of these anions are ignored or discounted; rarely are appropriate controls included. This study used five soils varying in pH, clay content, and organic matter to determine whether salinity from counter-ions contributed to or confounded metal phytotoxicity. Varying rates of Pb and Zn were applied to soils with or without a leaching treatment to remove the metal counter-ion (NO3 -). Lactuca sattva (lettuce) plants were grown in metal-treated soils, and plant dry weights were used to determine median effective concentrations where there was a 50% reduction in yield (EC50s) on the basis of total metals measured in the soil after harvest. In two of the five soils, leaching increased the EC50s significantly for Zn by 1.4- to 3.7-fold. In three of the five soils, leaching increased the EC50s significantly for Pb by 1.6- to 3.0-fold. The shift in EC50s was not a direct result of toxicity of the nitrate ion but was an indirect effect of the salinity increasing metal concentrations in soil solution and increasing its bioavailability for a given total metal concentration. In addition, calculation of potential salinity changes in toxicological studies from the addition of metals exhibiting strong sorption to soil suggested that if the anion associated with the metal is not leached from the soil, direct salinity responses could also lead to significant overestimation of the EC50 for those metals. These findings question the relevance of the application of single-metal salts to soils as a method of assessing metal phytotoxicity when, in many cases in our environment, Zn and Pb accumulate in soil over a period of time and the associated counter-ions are commonly removed from the soil during the accumulation process (e.g., roof and galvanized tower runoff). [source] Role of Endogenous Vintage Specific Depreciation in the Optimal Behavior of FirmsINTERNATIONAL JOURNAL OF ECONOMIC THEORY, Issue 3 2008Cagri Saglam D92; O33; E22; C61 This paper studies the firms' capital accumulation process in a vintage capital model with embodied technological change. We take into account that depreciation is endogenous and in particular associated with vintage specific maintenance expenditure. We prove that maintenance is a local substitute for investment as soon as the marginal cost of maintenance is strictly increasing. We show that maintenance and investment in new capital goods appear as complements with respect to the changes in productivity, cost of maintenance, fixed cost of operation, efficiency of maintenance services and appear as substitutes with respect to the price of new machines. Allowing for investment in old vintages, we determine that investment in old machines appears as a substitute of both investments in new machines and maintenance services. We end up by analyzing the effects of technological progress on optimal plans and prove that a negative anticipation effect can occur even without any market imperfections. [source] Divalent metal transporter 1 up-regulation is involved in the 6-hydroxydopamine-induced ferrous iron influxJOURNAL OF NEUROSCIENCE RESEARCH, Issue 14 2007Ning Song Abstract The reasons underlying the high iron content found in the substantia nigra (SN) of Parkinson's disease (PD) are largely unknown. We suppose, based on our previous studies, that the newly discovered iron transporter divalent metal transporter 1 (DMT1) might be involved in this SN iron accumulation process. To investigate this, we first observed the cellular expression of DMT1 in rat SN, both with the iron response element (+IRE) and without the IRE (,IRE) forms. The results showed that both forms of DMT1 were expressed on neurons, astrocytes, and microglia but not on oligodendrocytes. We further observed the relationship between the increased iron influx and DMT1 expression in 6-hydroxydopamine (6-OHDA)-treated C6 cells. 6-OHDA (10 ,mol/liter) caused a significant increase in ferrous iron influx, with the increased expression of DMT1+IRE, both in protein and in mRNA levels, whereas no change was observed for DMT1,IRE. To clarify further that the increased expression of DMT1 was not due to the increased intracellular iron content, C6 cells were overloaded with ferric ammonium citrate (100 ,g/ml). Decreased expression of both forms of DMT1 was observed. Our data suggest that DMT1 is highly expressed in rat SN in a cell-specific manner. Increased DMT1+IRE expression is the mechanism behind ferrous iron influx induced by 6-OHDA treatment in C6 cells. This may give some evidence for the involvement of DMT1 in the iron accumulation in PD. © 2007 Wiley-Liss, Inc. [source] CAPITALISTS, WORKERS AND SOCIAL SECURITYMETROECONOMICA, Issue 2 2007Thomas R. Michl ABSTRACT This paper elaborates an exogenous growth model that nests overlapping generations of workers who save for life cycle reasons with dynastic agents who save for bequest reasons (,capitalists'). The model overcomes Marglin's objection that the overlapping generations framework requires special assumptions about technology, and it also provides a natural environment to revisit Samuelson's analysis of lump-sum transfers between generations. The ability of a benevolent planner to improve workers' welfare is severely restricted by the control capitalists exercise over the accumulation process. Prefunding social security assumes renewed significance because it overcomes this restriction. [source] A critical evaluation of the brain efflux index method as applied to the nitric oxide synthase inhibitor, aminoguanidineBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 9 2001Joseph J. Raybon Abstract The Brain Efflux Index (BEI) method is an in vivo procedure designed to quantitate saturable efflux mechanisms resident at the blood,brain barrier (BBB). The present work utilized the BEI method to assess the BBB efflux mechanisms of [14C]aminoguanidine, a nitric oxide synthase inhibitor. The BEI for [14C]aminoguanidine was >100% (relative to [3H]inulin diffusion) over a range of 41,184 pmol after 40 min. The unusually high retention (>100%) of [14C]aminoguanidine suggested brain parenchymal sequestration, either by neuronal uptake or tissue protein binding. The uptake of [14C]aminoguanidine in dendritic neuronal endings (synaptosomes) showed a saturable concentration dependency, consistent with a carrier-mediated process. Nonlinear least-squares regression yielded the following Michaelis,Menten and diffusional (kns) parameters for synaptosomal [14C]aminoguanidine uptake: Vmax=118.50± 28.77 pmol x mg protein,1/3 min; Km=58.34±8.33 ,M; kns=0.15±0.029 pmol x mg protein,1/3 min/,M; mean±SEM; n=3 concentration profiles). Protein binding studies using brain tissue showed negligible binding. In summary, this work identified three principle findings: (1) An apparent lack of quantifiable aminoguanidine BBB efflux; (2) a previously undescribed synaptosomal accumulation process for aminoguanidine; and (3) an interesting limitation of the BEI technique where unusual brain parenchymal sequestration yields values >100%. Copyright © 2001 John Wiley & Sons, Ltd. [source] A Systematic Analysis of Coal Accumulation ProcessACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2008CHENG Aiguo Abstract: Formation of coal seam and coal-rich zone is an integrated result of a series of factors in coal accumulation process. The coal accumulation system is an architectural aggregation of coal accumulation factors. It can be classified into 4 levels: the global coal accumulation super-system, the coal accumulation domain mega-system, the coal accumulation basin system, and the coal seam or coal seam set sub-system. The coal accumulation process is an open, dynamic, and grey system, and is meanwhile a system with such natures as aggregation, relevance, entirety, purpose-orientated, hierarchy, and environment adaptability. In this paper, we take coal accumulation process as a system to study origin of coal seam and coal-rich zone; and we will discuss a methodology of the systematic analysis of coal accumulation process. As an example, the Ordos coal basin was investigated to elucidate the application of the method of the coal accumulation system analysis. [source] Non-destructive evaluation of fatigue and creep-fatigue damage by means of the induced-current focused potential drop techniqueFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 12 2001Y. Sato Quantitative evaluation of damage accumulation including crack initiation and propagation is one of the major concerns of industrial plant management and plant licence renewal. In order to develop a novel non-destructive testing (NDT) and non-destructive evaluation (NDE) technique for damage evaluation, the induced-current focused potential drop (ICFPD), originally proposed for a defect inspection, was employed. In this study, ICFPD was successfully applied to a non-destructive damage evaluation based on crack measurements. The measurements were taken on fatigued specimens with various degrees of fatigue damage. The ICFPD can clearly detect and differentiate the damage accumulation processes including crack initiation, small crack growth and subsequent macroscopic crack growth. In order to demonstrate the applicability of damage evaluation assessments based on small crack measurements, ICFPD has also been applied to creep,fatigue loading where damage evaluation of a fusion reactor material is based on small crack measurements by the ICFPD technique and a novel methodology is proposed. [source] ,Brain circulation' and transnational knowledge networks: studying long-term effects of academic mobility to Germany, 1954,2000GLOBAL NETWORKS, Issue 3 2009HEIKE JÖNS Abstract ,Brain circulation' has become a buzzword for describing the increasingly networked character of highly skilled migration. In this article, the concept is linked to academics' work on circular mobility to explore the long-term effects of their research stays in Germany during the second half of the twentieth century. Based on original survey data on more than 1800 former visiting academics from 93 countries, it is argued that this type of brain circulation launched a cumulative process of subsequent academic mobility and collaboration that contributed significantly to the reintegration of Germany into the international scientific community after the Second World War and enabled the country's rise to the most important source for international co-authors of US scientists and engineers in the twenty-first century. In this article I discuss regional and disciplinary specificities in the formation of transnational knowledge networks through circulating academics and suggest that the long-term effects can be fruitfully conceptualized as accumulation processes in ,centres of calculation'. [source] System Dynamics as a Structural Theory in Operations ManagementPRODUCTION AND OPERATIONS MANAGEMENT, Issue 3 2008Andreas Größler The purpose of the paper is to demonstrate the usefulness of (1) system dynamics as a structural theory for operations management and (2) system dynamics models as content theories in operations management. The key findings are that, although feedback loops, accumulation processes, and delays exist and are widespread in operations management, often these phenomena are ignored completely or not considered appropriately. Hence, it is reasoned why system dynamics is well suited as an approach for many operations management studies, and it is shown how system dynamics theory can be used to explain, analyze, and understand such phenomena in operations management. The discussion is based on a literature review and on conceptual considerations, with examples of operations management studies based on system dynamics. Implications of using this theory include the necessary re-framing of some operations management issues and the extension of empirical studies by dynamic modeling and simulation. The value of the paper lies in the conceptualization of the link between system dynamics and operations management, which is discussed on the level of theory. [source] Development of homochiral peptides in the chemical evolutionary process: Separation of homochiral and heterochiral oligopeptidesCHIRALITY, Issue S1 2003Toratane Munegumi Abstract Living organisms have one-handed structures of L-amino acids in proteins and D-sugars in nucleic acids. Although the origins of each one-handed structure (or homochirality) have been discussed for many years, these discussions have been restricted to monomeric compounds, such as amino acids and monosaccharides, or their stereospecific condensation reactions. Oligomers of these compounds have to be considered in the accumulation processes of homochirality because of the differences in physical properties of the diastereomers. High-performance liquid chromatography (HPLC) and the calculation of the partition coefficient values showed that the peptides having heterochiral sequences like L-Ala-D-Ala or D-Ala-L-Ala were more hydrophobic than the peptides having homochiral ones (L-Ala-L-Ala and D-Ala-D-Ala). Similar results were given from the calculation of most linear dipeptides and all cyclic ones composed of Gly, Ala, Val, or Asp. In addition, longer homo-oligopeptides composed of Ala, Val, or Asp also gave similar results. This general tendency would be useful for the separation of diastereomeric oligopeptides in water. The results also suggest that the separation of the homochiral peptides from the heterochiral ones by their solubility in water could have progressed in a primitive hydrosphere. Chirality 15:S108,S115, 2003. © 2003 Wiley-Liss, Inc. [source] | ||||||||||||||||