An alternative to synthetic materials for use in solar pond liners is to select clayey soils as hydraulic barriers. This option reduces the cost of construction and the risk of contamination of subsoil and groundwater by hot brines. This paper deals with the physical, chemical and hydraulic properties of different soils tested mainly as compacted clay liners. The underdeveloped nations have the option to use this type of liner, but before doing so several tests are recommended, including those for soil and water composition, permeability, plasticity and X-ray diffraction analysis. In this investigation the following samples are analyzed: native clayey soils with illite, montmorillonite and halloysite, treated and non-treated bentonites in powder and granulated form, a mixture of zeolite and sodium bentonite, and industrial minerals composed largely of halloysite, kaolinite and attapulgite selected clays. Neutral salt aqueous solutions (NaCl and ...
Abstract This research aimed to investigate coarse root systems of Jarrah (Eucalyptus marginata Donn ex Sm.) trees at a 13-year-old restored bauxite mine site in south-western Australia. Excavations in an area with small trees (low-quality site) revealed that deep ripping equipment failed to penetrate the cemented lateritic subsoil, restricting coarse roots (roots >5 mm in diameter) to the top 0.5 m of the soil profile, resulting in fewer (1,344 stems/ha) and smaller (mean height 4.5 m) Jarrah trees. An adjacent area within the same pit (high-quality site), with a stand density of 3,256 stems/ha and a mean height of 8.0 m, had a kaolinitic clay subsoil which coarse roots penetrated to the average ripping depth (1.5 m). Trees at the low-quality site did not penetrate the subsoil with their ...
The aim of this work is to determine and compare the dosimetric properties of NaCl and KCl samples using infrared-stimulated luminescence (IRSL) technique. For a material to be used as dosimeter, both the IRSL temperature dependence and the radiation dose response have critical importance. In this work the IRSL characteristics from NaCl and KCl samples were experimentally investigated as a function of temperature and laboratory radiation doses. Dosimetric properties of NaCl and KCl samples were found significantly different. The IRSL signals displayed by NaCl were found to be more stable, reliable and agreeable than those of KCl.
Two strains of Rhizobium: Rhizobium Tropici and Mesorhizobium Ciceri nodulating respectively common bean and chickpea were treated by gamma irradiation (60Co) source. Radiosensibility analysis showed that 800 Gy was the biggest dose supported by these two strains. We isolated gamma irradiated resistant strain in order to select mutant of them which can supported salt stress and phosphorus deficiency. Salinity analysis showed that Mesorhizobium Ciceri 835 strain, can tolerate up to 18g/l (273 mM NaCl) of salt, whereas, their irradiation mutants tolerate salinity up to 33g/l (564mM. NaCl) Rhizobium Tropici CIAT899 can survive at 20g/l (342 mM) either for control strain or mutants. Analysis of phosphorus deficiency showed that either Rhizobium Tropici CIAT899, or Mesorhizobium Ciceri 835 can survive in medium without phosphore. Our results permit us to screen mutants tolerant to these stresses wide spread in Mediterranean soil. In this study, we ...
This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N{sub 2}/H{sub 2}) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole size of screen setup ...
This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N_2/H_2) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole size of screen setup ...
The crystallization of calcium sulfate from aqueous solutions with NaCl is both geological and industrial interest because NaCl is the dominant solute in natural brines and many industrial fluids. Induction periods for the nucleation of calcium sulfate dihydrate were experimentally determined as a function of supersaturation in NaCl solutions from 0 to 6 m at 25 C and in 3.0-m NaCl solutions at temperatures from 25 to 90 C. Using classic nucleation theory, the interfacial tension between gypsum and 3.0-m NaCl solution was estimated to be about 39 mJ/m[sup 2] at 25 C and increases with increasing temperature (to 63 mJ/m[sup 2] at 90 C). It was observed that the induction period decreases with increasing NaCl concentrations up to 3 m and then starts to increase slightly at a given temperature and saturation state. The electrolyte effect on nucleation was ...
Proline accumulation in NaCl-treated excised barley (Hordeum vulgare var Larker) leaves was studied. Leaves were treated by placing the cut end in NaCl solutions and allowing the salt...Full Text Available
Dose-dependent behavior of the infrared stimulated luminescence (IRSL) decay from NaCl has been studied experimentally using only one aliquot irradiated with a range of 2-200 Gy {beta}-radiation doses. It was observed that the maximum IRSL intensity has not changed by an increase in dose though the total intensity increased as expected. Considering the possible implications of our findings for dosimeter, the results were compared with the other studies and discussed.
The effects of fluoride on the corrosion behavior of Titanium Grade 7 (0.12-0.25% Pd) have been investigated. Up to 0.1 mol/L fluoride was added to the NaCl brines at 95oC, and three pH values of 4, 8, and 11 were selected for studying pH dependence of fl...
Anode polarization measurement is performed in mixed solution of NaCl and NaF using SUS 304 steel to investigate whether F[sup -] promotes or inhibits pitting corrosion. Pitting corrosion does not occur in the solution of NaF only, but passive state is broken above a certain critical potential, resulting in overall dissolution. When anode polarization measurement is made in a solution of fixed concentration NaCl added with NaF, pitting corrosion is inhibited at a certain critical concentration. F[sup -] has no effect on corrosion potential in the solution up to this critical concentration. Overall dissolution occurs in the solution with higher concentration than the critical concentration, the current value at that time agrees with that in the solution of NaF alone, and no effect of Cl[sup -] is shown. The concentration range where pitting corrosion occurs and that where overall dissolution occurs are divided by a straight line when they are ...
The papers presented at the symposium had covered three general areas in which isotopes could have been beneficially used. these areas are: -Water use and water use efficiency studies. -Ground water investigations -Water problems in the arab countries. The individual papers had dealt with these subjects: -Hydrological research in the arab countries by use of radioisotopes. -The perspectives of use of radioisotopes in hydrological studies in Syria. -Water use efficiency and sub-soil water studies. -Sea water inclusion in a coast el aquifers in Lebanon. -Irrigation requirements of crops in Lebanon as determined by a Neutron probe with reference to other methods. -The use of the neutron moisture meter and other methods of the determination of the evapotranspiration of maize. -Ground water investigations, dating and nuclear methods applied to hydrology. -Ground water investigation in Wa di El-Nat run, U.A.R. -Velocity distribution along the pumped well using ...
Because of the environmental hazard of organic solvents such as chlorinated or aromatic hydrocarbons, water soluble and biodegradable substitutes have come into use. It should be assessed how they affect soil and aquifer when spilled in leaks or accidents. This was simulated in a model system using methanol and percolation columns, one filled with material from the unsaturated subsurface and two with different materials from aquifers. The results reveal that a spill of the substitutes can also cause problems. In homogeneous soils and at long retention times until the substance reaches the aquifer, sorption and biological degradation are most likely to prevent contamination of the groundwater. When oxygen supply in the subsurface is insufficient, reducing conditions occur and sulphide is formed. The data show that much more methanol was eliminated than reflected by the consumption of electron acceptors. This indicates that sorption and anabolic turnover of the microorganisms play an ...
Open pit oil sands mining involves the disturbance of thin overburden covers of Boreal forest lands that must be returned to equivalent land capability after mining activities have ceased. Before mining starts, any wetlands are drained, timber is harvested, and peat, topsoils and subsoils are stockpiled for later use. This article discussed wetland reclamation activities conducted by Suncor Energy at its open pit mining operations. Research facilities were constructed in order to determine if wetlands constructed with consolidated tailings (CT) and pond effluent water (PEW) were able to support a sustainable vegetation community. Thirty-three cat-tail plots were established at the facility as well as unplanted plots in order to determine how quickly natural establishment occurred. Shoreline plug transplants and transplants from a natural saline lake were also introduced. Within 5 years, over 23 plant species had naturally colonized the CT wetlands. However, ...
Abstract:- Brine solution injection of beef contaminated with-Escherichia coli-O157:H7 on its surface may lead to internalization of pathogen cells and/or cross-contamination of the brine, which when recirculated, may serve as a source of new product contamination. This study evaluated survival of-E. coli-O157:H7 in brines formulated without or with antimicrobials. The brines were formulated in sterile distilled water (simulating the composition of freshly prepared brines) or in a nonsterile 3% meat homogenate (simulating the composition of recirculating brines) at concentrations used to moisture-enhance meat to 110% of initial weight, as follows: sodium chloride (NaCl, 5.5%) + sodium tripolyphosphate (STP, 2.75%), NaCl + sodium pyrophosphate (2.75%), or NaCl + STP combined with potassium ...
The effect of NaCl and Na_2SO_4 treatments on chlorophyll content, rate of "1"4C assimilation and products of photosynthesis in peanut (Arachish hypogaea L.) variety TMV-10 has been investigated. It was observed that chlorophyll content was affected mainly by NaCl, Na_2SO_4 treatment lowered the rate of photosynthetic "1"4CO_2 fixation. The analysis of labelled products revealed that the salts affect the carbon metabolism differently. The radioactivity was found to be accumulated in fractions of sugars and sugarphosphates in the leaves of NaCl treated plants. Na_2SO_4 treatment brought about considerable decline in labelling of sugars and an increase in labelling of amino acids and sugarphosphates. (orig.).
The kinetics of calcium sulfate crystal growth is of importance in various fields, such as geochemistry, desalination technology, petroleum industry, and water and wastewater treatment. The seeded crystal growth rate of calcium sulfate dihydrate was measured as a function of supersaturation in NaCl electrolyte solutions from 0 to 6 m at temperatures of 25, 50, 70, and 90 C. The growth followed a second-order parabolic rate law with activation energies greater than 53 kJ/mol which suggested the surface reaction as the rate-limiting step. It was observed that the rate constant and the activation energy are solution composition dependent. The rate constant increases with NaCl concentration up to 3 molal and then begins to fall slightly. The activation energy dropped from 61 kJ/mol in the pure Ca-SO[sub 4]H[sub 2]O system to 53 kJ/mol in 3.0 m NaCl solutions. The electrolyte effect was similar to the crystal solubility behavior ...
The effects of thiosulfate ion and solution pH on pitting corrosion of Alloy 690 in chloride solution were explored. Potentiodynamic polarization measurements were conducted to evaluate pitting corrosion susceptibility of Alloy 690 in these environments. The results showed that pitting corrosion occurred in the mill-annealed (1050 deg. C/5min) Alloy 690 in 1 wt% NaCl solution but not in 0.1 M Na{sub 2}S{sub 2}O{sub 3} solution. The value of pitting nucleation potential (E{sub np}) determined in 1 wt% NaCl solution (without Na{sub 2}S{sub 2}O{sub 3} ) increased with increasing solution pH value in the range of 2-10. The addition of Na{sub 2}S{sub 2}O{sub 3} to 1 wt% NaCl solution greatly affected the pitting corrosion behavior, which was dependent on concentration. The preformed nickel sulfide surface film due to the presence of Na{sub 2}S{sub 2}O{sub 3} caused Alloy 690 to become more susceptible to pitting corrosion in 1 ...
NaCl doped MgCl_2.nEtOH adducts were prepared by ball-milling MgCl_2.2.5EtOH with NaCl. Both the ball-milled MgCl_2.nEtOH/NaCl mixture and pure MgCl_2.2.5EtOH adducts were analyzed by X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetry (TG) and differencial scanning calorimetry (DSC). A simple MgCl_2.nEtOH/NaCl mixture without ball-milling treatment was also studied for comparison. Two kinds of mixed crystals, Na_2MgCl_4 and NaMgCl_3, were found to be formed in a ball-milled mixture that contained 16 mol.% NaCl. TG and DSC analysis of the samples also provided indirect evidences supporting the presence of the mixed crystals in the ball-milled mixture. Adding certain amounts of NaCl in MgCl_2.2.5EtOH adduct, either by co-milling or by simple mixing, greatly increased the thermal stability of the adduct, but thermal decomposition behaviour of the ball-milled mixture was still ...
In Experiment I, lever pressing by squirrel monkeys was maintained under a sequence of variable-interval, multiple variable-interval variable-interval, and multiple variable-interval extinction schedules...Full Text Available
In PWR's steam generators, ''denting'' resulted from corrosion of support plate material, carbon steel is an important problem. The role of chlorides in corrosion acceleration of mild steel was studied. Corrosion tests were conducted at temperature from 100"0C to 280"0C in deaerated solutions of NaCl and MgCl_2 which are main content of sea water. 1) Solution of MgCl_2 was more corrosive than that of NaCl. The more increased in concentration of each chloride solution, the more corrosive in MgCl_2 soln. but the less corrosive in NaCl soln. 2) The rate of corrosion in the mixed solution of NaCl and MgCl_2 was governed by the concentration of MgCl_2 soln. The corrosion behaviour in sea water was suggested to be not controlled by NaCl but by MgCl_2. 3) Acidification of MgCl_2 soln. could be evaluated by experiment at 100"0C, the degree of acidification increased with increasing the ...
We consider chemical reaction networks taken with mass action kinetics. The steady states of such a system are solutions to a system of polynomial equations. Even for small systems the task of finding the solutions is daunting. We develop an algebraic framework and procedure for linear elimination of variables. The procedure reduces the variables in the system to a set of "core" variables by eliminating variables corresponding to a set of non-interacting species. The steady states are parameterized algebraically by the core variables, and a graphical condition is given for when a steady state with positive core variables necessarily have all variables positive. Further, we characterize graphically the sets of eliminated variables that are constrained by a conservation law and show that this conservation law takes a ...
Research highlights: #-># The Y-intermetallic can accelerate corrosion and Y can increase the protectiveness of the surface layer. #-># In 0.1 M NaCl, the corrosion rate of Mg-Y alloys increased with increasing Y due to the Y intermetallic. #-># In 0.1 M NaCl, there was filiform corrosion. #-># In 0.1 M Na_2SO_4, the corrosion rate of Mg-Y alloys decreased with increasing Y in the range 3-7%Y. #-># Hydrogen evolution was observed from particular parts of the alloy surface. - Abstract: Corrosion of Mg-Y alloys was studied using electrochemical evaluations, immersion tests and direct observations. There were two important effects. In 0.1 M NaCl, the corrosion rate increased with increasing Y content due to increasing amounts of the Y-containing intermetallic. In 0.1 M Na_2SO_4, the corrosion rate decreased with increasing Y content above 3%, attributed to a more protective surface film, despite the ...
Soils of arid regions of Central Asia contain salts of different types that may differentially affect seed germination and plant development. We studied effect of NaCl, Na2SO4, 2NaCl + KCl + CaCl2 and 2Na2SO4+K2SO4+MgSO4 on germination of Kochia prostrata and Kochia scoparia seeds under a range of concentrations from 0.5 to 5% and at two constant temperature regimes +22 degrees C and +6 degrees C. The observed salt tolerance limit of germination at constant temperature +22 degrees C for both species was 5-6%, while at low temperature (+6 degrees C) this limit was 2%. The salt tolerance of young plants (before flowering) was 3% for NaCl. Low concentrations of sulfuric and mixed salts had a stimulating effect on seed germination in K. prostrata. Despite similarity of salt-tolerance limits...
The partial pressures of the components (ThCl_4, MCl and MThCl_5) in the saturated vapours of ThCl_4 solutions in molten LiCl, NaCl, KCl, RbCl and CsCl are determined as a function of temperature (900 to 1200 K) and ThCl_4 concentration (2 to 50 mol% ThCl_4) by dynamic method. Thorium tetrachloride volatility is shown to exceed that of alkali chloride from the melts containing less than 98 LiCl or NaCl, 83 KCl, 67 RbCl and 48 mol% CsCl. From experimental observations the decomposition potential of the electrolytes under investigation was estimated in temperature and concentration ranges of our measurements. Under otherwise equal conditions, it increases in the series of alkali chlorides from LiCl to CsCl. (author).
Hydrostatic weighing was used to measure the pre-melt density of crystalline eutectic mixtures of alkaline metal chlorides of the compositions (mole fractions): 0.605 LiCl + 0.395 CsCl, 0.585 LiCl + 0.415 KCl, 0.297 NaCl + 0.246 KCl + 0.457 CsCl, and 0.348 NaCl + 0.652 CsCl with melting points 598, 628, 753, 763 K, respectively, as a function of temperature. In the same temperature ranges, the compressibility and molar volume of eutectics as well as their sudden change upon melting were estimated. Unusual variations of these properties were revealed near the crystal/liquid phase transition, which were related to local disordering of particle configuration
Abstract A method to grow the halophilic archaeon Haloferax volcanii in microtiter plates has been optimized and now allows the parallel generation of very reproducible growth curves. The doubling time in a synthetic medium with glucose is around 6-h. The method was used to optimize glucose and casamino acid concentrations, to clarify carbon source usage and to analyze vitamin dependence. The characterization of osmotolerance revealed that after a lag phase of 24-h, H. volcanii is able to grow at salt concentrations as low as 0.7-M NaCl, much lower than the 1.4-M NaCl described as the lowest concentration until now. The application of oxidative stresses showed that H. volcanii exhibits a reaction to paraquat that is delayed by about 10-h. Surprisingly, only one of two amino acid auxotrophi...
The kinetics of the electropolymerization of 3-amino-1,2,4-triazole on a brass substrate in alkaline solution containing methanol was investigated using cyclic polarization, chronoamperometry, electrochemical impedance techniques and scanning electronic microscopy. The polymeric film was prepared by successive cycles of potential of a 60Cu-Zn electrode between 0 and 1.6 V. During the second cycle, the oxidation peak of the monomer disappears indicating the formation of the insulating film. We have also shown that the monomer oxidation reaction is essentially irreversible and controlled by a diffusion process. The protective effect of the film formed on brass has been studied in a 3%NaCl and 3%NaCl + S{sup 2-} solution. The results showed important inhibition efficiency, about 96% for 4 h of testing time.
The kinetics of the electropolymerization of 3-amino-1,2,4-triazole on a brass substrate in alkaline solution containing methanol was investigated using cyclic polarization, chronoamperometry, electrochemical impedance techniques and scanning electronic microscopy. The polymeric film was prepared by successive cycles of potential of a 60Cu-Zn electrode between 0 and 1.6V. During the second cycle, the oxidation peak of the monomer disappears indicating the formation of the insulating film. We have also shown that the monomer oxidation reaction is essentially irreversible and controlled by a diffusion process. The protective effect of the film formed on brass has been studied in a 3%NaCl and 3%NaCl+S2- solution. The results showed important inhibition efficiency, about 96% for 4h of testing ...
Corrosion behavior of deposition coated specimens prepared by the technique proposed by the authors is investigated in salt immersion tests, and also those of pure magnesium, 3N, 4N and 6N grades, and magnesium alloys, AZ31 and AZ91E, are investigated for comparison. Inhomogeneous corrosion occurs in AZ31 and AZ91E alloys when buffered solutions with pH values of 6.5 and 9.0 including 1% NaCl and a conventional 3% NaCl solution are used for immersion tests, while 6N-Mg shows homogeneous corrosion in such solutions. Corrosion behavior of the deposition coated specimen resembles that of 6N-Mg. Purification process included in the deposition coating technique provides homogeneity in microstructural and electrochemical terms, which results in improving corrosion resistance. (orig.)
The corrosion behavior of the sputter-deposited amorphous or nanocrystalline W-Nb alloys is studied in 10% NaCl, 0.1 and 1 M NaOH solutions at 24 deg. C, open to air using immersion tests and electrochemical measurements. Niobium metal acts synergistically with tungsten in enhancing the corrosion resistance of the W-Nb alloys so as to show lower corrosion rates than the corrosion rates of the alloy-constituting elements in almost all examined solutions. Corrosion rates of W-Nb alloys are about more than one order of magnitude less than that of the sputter-deposited tungsten and even lower than that of sputter-deposited niobium. The stability of the anodic passive films formed on the W-Nb alloys increase with niobium content.
The basic feature in the functional ecology of any mire ecosystem is retardation of the effective decay of organic material resulting in a conspicuous accumulation of plant debris as peat overtime. The carbon accumulation process is slow, and climatic change may have an impact on the carbon cycle of peatlands, therefore, it has been of interest to study the rate of carbon accumulation by geological methods from dated peat strata. The approach is hampered by several facts. First, the mires vary enormously as to their vegetation and hydrology and hence their production and decay properties. It follows that a great number of study sites are needed. Second, the peat in mires expands both vertically and laterally, and this requires a spatial reconstruction of carbon accumulation within a mire basin. Third, simple geological methods cannot account for the actual rate of carbon accumulation in peat, and finally, an additional carbon sink in the mire ecosystems can be the mineral ...
The chemical reaction between nitric acid and sodium chloride was investigated in onder to provide preliminary information for subsequent studies on the interaction between simulated Purex waste solution and salt. The reaction is characterized by the production of chlorine and nitrosyl chloride and can be considered to be the same as the aqua regia reaction. Within the limits of the conditions imposed by the projected field studies, the acid concentration and temperature are the two parameters which control the extent of the interaction. (auth)
Thermogalvanic corrosion of St3 steel in a temperature range from 25 to 50{degrees}C with a 3.84{degrees}C/cm gradient was studied in a neutral media flow. It is shown that the thermogalvanic effect on the pitting corrosion of water-cooled heat exchangers is decisive but dual. Depending on the composition of the cooling medium, thermogalvanic corrosion may either enhance (0.5 M NaCl) or inhibit (tap water) pitting corrosion.
The pitting corrosion resistance of three different types of stainless steel implanted with silicon is investigated using the potentiokinetic polarization technique. The specimens are tested in 3% NaCl and 0.1 N HCl solutions. Silicon ion implantation inhibits pitting corrosion of the steels in both aqueous media. The corrosion resistance depends on the silicon dose. Post implantation annealing only slightly alters the localized corrosion. (author).
The rapid corrosion of carbon steels in high temperature, acid chloride solutions is shown to be rate limited by the anodic reaction, 3Fe + 4H_2O = Fe_3O_4 + 8H"+ + 8e"-, based on experiments which find that the corrosion rate in 0.1M NiCl_2 solution has an activation energy of 60 kJ/ mole and is unaffected by adding NaCl or by replacing NiCl_2 with PtCl_4. (author).
A method for enrichment of the ppb level of cadmium in water by using the coagulation of soybean protein by adding acids or its complex-forming character with heavy metal ions was investigated. After adding fixed amounts of soybean milk and 2% sodium diethyldithiocarbamate(DDTC) aqueous solution and a suitable amount of delta-gluconic lactone (delta-GL) to a sample solution, the mixture was heated to boiling in order to coagulate the protein. The coagulum(soybean curd) was separated from the suspension by centrifugation and burned to ashes with a low temperature plasma asher. Then the cadmium enriched in it was determined by atomic absorption spectrometry. Various factors such as the pH of the sample solution, the amounts of soybean milk and the collection additives, and the concentration of NaCl in the sample solution on the recovery of cadmium were examined systematically. The best recovery was obtained under the following conditions: To a certain amount of ...
In the present work, electrochemical measurements and corrosion tests in NaCl solutions were carried out to study the effect of aging treatments on pitting corrosion behavior in a 8090 alloy and its high purity Al-Li binary alloy analogue. The pitting corrosion characteristics and corrosion resistance of the 8090 alloy have been determined in relation to precipitation microstructures. (orig.).
Corrosion characteristics of Al and Cu thin films have been studied in cyclic fog tests using tap water fog and fog created with 0.1% NaCl solution in tap water. Likewise, their corrosion features have been analyzed in continuous immersion testing in the laboratory in distilled water, tap water, in 0.1% NaCl and 3.5% NaCl solutions in distilled water. The corrosion potentials and the corrosion currents of these thin films change and reach steady state values after some time. However, steady state is not realized in 3.5% NaCl solutions. The corrosion current density data have been used to calculate lifetime of 1 {mu}m thick thin films of Al and Cu in the various tests, and assuming that the fog test data would hold under normal exposure conditions, life spans for these thin film sensor elements in actual exterior exposure have also been calculated. According to estimates, an Al-TF of about 1 {mu}m would ...
Attention is given to the folowing topics: population I and II variable stars; LP variables, the sun, and mass determination; and predegenerate and degenerate variables. Particular papers are presented on alternative evolutionary approaches to the absolute magnitude of the RR Lyrae variables; the evolution of the Cepheid stars; nonradial pulsations in rapidly rotating Delta Scuti stars; dynamical models of dust shells around Mira variables; and pulsations of central stars of planetary nebulae.
High salinity is one of the main factors limiting cotton growth and productivity. The genes that regulate salt stress in TM-1 upland cotton were monitored using microarray and real-time PCR (RT-PCR) with samples taken from roots. Microarray analysis showed that 1503 probe sets were up-regulated and 1490 probe sets were down-regulated in plants exposed for 3h to 100mM NaCl, and RT-PCR analysis validated 42 relevant/related genes. The distribution of enriched gene ontology terms showed such important processes as the response to water stress and pathways of hormone metabolism and signal transduction were induced by the NaCl treatment. Some key regulatory gene families involved in abiotic and biotic sources of stress such as WRKY, ERF, and JAZ were differentially expressed. Our transcriptome analysis might provide some useful insights into salt-mediated signal transduction pathways in cotton and offer a number of candidate genes as potential ...
Cerium is known to enter substitutionally in trivalent state when doped in alkali halides. Cerium doped NaCl crystals exhibit greatly enhanced thermoluminescence output upon X-irradiation at RT, the intensity of emission being about 10 times that in undoped crystals for similar dosage of irradiation. The cerium doped crystals give upon X-irradiation a very intense glow peak at 145degC with shoulders at 120degC and 210degC. Upon partially bleaching the crystal with F-light, the peak at 120degC becomes prominent probably due to faster bleaching of the glow at 145degC. From further optical bleaching studies, it is concluded that the glow peak at around 120degC is due to cerium centres in the irradiated crystal and the 145degC peak due to F centres. This F centre emission occurs at lower temperature, compared to that in the undoped crystals where it occurs at around 180degC. The spectral emission in the Ce doped crystals is in the blue-green region as compared to the ...
The partial pressures of the components (ThCl/sub 4/, MCl and MThCl/sub 5/) in the saturated vapours of ThCl/sub 4/ solutions in molten LiCl, NaCl, KCl, RbCl and CsCl are determined as a function of temperature (900 to 1200 K) and ThCl/sub 4/ concentration (2 to 50 mol% ThCl/sub 4/) by dynamic method. Thorium tetrachloride volatility is shown to exceed that of alkali chloride from the melts containing less than 98 LiCl or NaCl, 83 KCl, 67 RbCl and 48 mol% CsCl. From experimental observations the decomposition potential of the electrolytes under investigation was estimated in temperature and concentration ranges of our measurements. Under otherwise equal conditions, it increases in the series of alkali chlorides from LiCl to CsCl.
Peeled Avena sativa coleoptile sections have been used to study the control of solute uptake under conditions where the uptake is not limited by the cuticular barrier. In the presence of 2% sucrose, auxin enhances the rate at which the total osmotic solutes increase, but this appears to be a response to the increased growth rate, inasmuch as the auxin effect is eliminated when growth is inhibited osmotically. When sections are incubated in sucrose or in 10 millimolar NaCl, the osmotic concentration increases until a plateau is reached after 8 to 24 hours. Auxin has no effect on the initial rate of increase in osmotic concentration. This difference in steady-state osmotic concentration is, in part, a response to auxin itself, as it persists when auxin-induced growth is inhibited osmotically. The upper limit for osmotic concentration does not appear to be determined by the turgor pressure, inasmuch as a combination of sucrose and NaCl gave a ...
As a series of experimental determinations of the thermal diffusivity of molten alkali halides, this paper describes measurements on five molten alkali metal chlorides (LiCl, NaCl, KCl, RbCl, and CsCl) in the temperature range up to 1440 K by the forced Rayleigh scattering method. K[sub 2]Cr[sub 2]O[sub 7] is employed as a dye substance to color the transparent molten salts. In comparison with the present results converted into thermal conductivity, most of the previous experimental data obtained by steady-state methods show larger values, up to about five times, which may be due to the systematic error caused by the presence of convection and radiation. It is found that the thermal conductivity of these series of molten alkali metal chlorides decreases with increasing molecular weight, and their temperature coefficients are weakly negative. 24 refs., 9 figs., 6 tabs.
Oxygenated sterol compounds (OSC), when incubated for 1 hr with human erythrocytes in lipoprotein-depleted medium at concentrations of 0.625-5 x 10/sup -5/M, are inserted into the cell membrane and remain there despite subsequent washing of the cells. The insertion results in expansion of the surface area of the red cell ghost membrane, an increase in critical hemolytic volume, and as a consequence, in dimished osmotic fragility of the erythrocytes. This effect is seen with echinocyte-forming as well as with non-echinocyte-forming OSC. Erythrocytes treated with OSC do not differ from control cells with respect to their mean cell volume (MCV) in isotonic solution, water content, ion fluxes, and filterability through polycarbonate filters. The shift of the osmotic fragility curve toward lower NaCl concentrations is proportional to the amount of OSC inserted into the red cell membrane. 7BETA-Hydroxycholesterol, 22-ketocholesterol, and 20 ..cap ...
The corrosion resistance of steel-reinforced mortar specimens made from alinite cement was investigated using ordinary Portland cement (OPC) specimens as reference. The specimens were prepared and exposed in three different environments: continuous exposure in tap water, interrupted exposure in tap water, and interrupted exposure in 3.5% NaCl solution. The steel weight loss and the half cell potential were measured vs. exposure time, up to the age of 12 months. Pore solution extraction and analysis and porosity determination were also performed. In continuous exposure in tap water, alinite cement provided adequate protection against corrosion. In interrupted exposure in tap water, a higher corrosion was observed for alinite cement compared to OPC. In the case of interrupted exposure in 3.5% NaCl solution, the simultaneous action of free chlorides and oxygen resulted in the depassivation of steel reinforcing bars in alinite and Portland cement ...
Using an ab initio pseudopotential method within a generalized gradient approximation of the density functional theory, the structural, electronic, and phonon properties of SrS in the B1 (NaCl) and B2 (CsCl) structures have been studied. The calculated lattice constants, static bulk modulus, and first-order pressure derivative of the bulk modulus are reported for both the B1 and B2 structures and compared with previous experimental and theoretical calculations. Electronic band structures and densities of states have been derived for SrS. Subsequently, a linear-response approach to the density functional theory is used to derive the phonon frequencies and densities of states.
The oral administration of 2,3-dihydroxybenzoic acid (DHB) to rats injected intravenously 1 hr previously with "2"3"9Pu citrate caused an increase in urinary excretion of Pu about 8 times that of animals treated with 0.9% NaCl (controls). Liver retention of Pu was decreased from 18% at 2 days in the control animals to 11% in DHB-treated rats. The skeletal retention was similarly reduced from 56% in the control group to 40% in the DHB-treated animals.
Severe pitting corrosion occurred in a horizontal steel pipeline used to transport multiphase fluid, including water, oil, and natural gas, after 2 months of service. The pitting corrosion rate was up to 42 mm/year. Chemical analysis, X-ray diffractometry, and EDAX showed that the corrosion products mainly consisted of Fe9S8, FeCO3, and NaCl. Calcium containing inclusions were also found in the matrix of the steel, which may accelerate corrosion. The early failure was attributed to the high proportion of water, the slow flow velocity, and the use of unqualified material. (Author)
A computerized corrosion measuring system (EG and G model 350 A) was used to study the influence of Cr, Mo, Ti, Nb and W on the pitting corrosion of nickel base alloys in 3% NaCl at 90"0C. The electrochemical parameters under investigation are the corrosion potential E_c_o_r_r, pitting potential E_p and protection potential E_p_p. The corrosion behaviour of nickel base alloys were studied by using pitting scan and potentiostatic techniques. Values of corrosion potential, pitting potential and protection potential were used for a ranking of alloys for corrosion resistance.
Differences in the biological disposition and in the effects of the stable lithium isotopes, Li-6 and Li-7, in animals were characterized. A somewhat higher toxicity was associated with WLiCl compared to XLiCl with NLiCl intermediate. All lithium treatments increased water intake and resulted in weight gain. Peak plasma concentration was slightly high for 6Li than 7LiCl suppressed action potential amplitudes during tetanic stimulation more than NaCl when added to Renger solution bathing ganglia.
Experiments were conducted which established that the higher passivating capacity of Ni/sub 60/Nb/sub 40/ alloys in the amorphous state and higher efficiency of the anodic process of generation of chlorine (2 N NaCl + HCl to pH = 0) in comparison with the crystalline state are determined by higher homogeneity and density of the passive films formed on the amorphous alloy and by higher electron conduction which depends directly on the difference in the structure of the passive films formed on the alloys in the amorphous and crystalline states.
The Smidsrod empirical stiffness parameter (B) of A. occidentale and A. lebbeck gum were determined using the correlation of intrinsic viscosity [#eta#] with ionic strength. The B value of 0.204 and 0.193 found respectively for A. occidentale and A. lebbeck suggests a flexible the molecule. The ionic strength has a greater influence on the [#eta#]. The decrease of [#eta#] increase of I, from 0.01 M to 0.1 M of NaCl, is higher for A. lebbeck (89%) than for A. occidentale (19%). (author)
A common property of aging in all animals is that chronologically and genetically identical individuals age at different rates. To unveil mechanisms that influence aging variability, we identified markers...Full Text Available
Variability in motor performance decreases with practice but is never entirely eliminated, due in part to inherent motor noise. The present study develops a method that quantifies how performers...Full Text Available
BackgroundDue to the increased accuracy of Copy Number Variable region (CNV) break point mapping, it is now possible to say with a reasonable degree of confidence whether a gene...Full Text Available
Operation of an X-ray spectrometer based on a spherical variable-line-spacing (VLS) grating is analyzed using dedicated ray-tracing software allowing fast optimization of the grating parameters and...Full Text Available
Background/AimsTo explore different definitions of intra-individual variability (IIV) to summarize performance on commonly utilized cognitive tests (Mini Mental State Exam; Clock...Full Text Available
This work reports the design of and experimentation with a topographically patterned cell culture substrate of variable local density and anisotropy as a facile and efficient platform to guide...Full Text Available
BackgroundVariable platelet response to clopidogrel has been widely observed. Studies have shown that the mean aggregation response to clopidogrel can be changed...Full Text Available
BackgroundIn cancer research, most clinical variables have already been investigated and are now well established. The use of transcriptomic variables has raised two problems: restricting...Full Text Available
A common approach used to fuse simultaneously recorded EEG and fMRI is to correlate trial-by-trial variability in the EEG, or variability of components derived therefrom, with the blood oxygenation...Full Text Available
Several Mg-Y binary ribbons with Y content up to {approx}17.9 at.% were fabricated by melt-spinning. X-ray diffraction (XRD) revealed that the phase structure changes with increasing Y content from extended solid solution to partially amorphous, and then fully intermetallic Mg{sub 24}Y{sub 5}. Anodic potentiodynamic polarization performed in 0.01 M NaCl electrolyte (pH=12) revealed improved anodic passivity behavior compared to pure Mg for all the Mg-Y alloys. X-ray photoelectron spectroscopy (XPS) revealed that the improved passivity of Mg-Y was more related to the elemental oxidation state rather than the concentration of the surface components. To study the effect of Cl{sup -} ion on the passivity behavior, anodic potentiodynamic and potentiostatic polarization were performed on Mg-17.9 at.% Y in alkaline (pH=12) NaCl electrolytes containing Cl{sup -} ion in the concentration range from 0.00 to 0.50 M. The passive films formed in 0.01 M ...
Several Mg-Y binary ribbons with Y content up to #approx#17.9 at.% were fabricated by melt-spinning. X-ray diffraction (XRD) revealed that the phase structure changes with increasing Y content from extended solid solution to partially amorphous, and then fully intermetallic Mg_2_4Y_5. Anodic potentiodynamic polarization performed in 0.01 M NaCl electrolyte (pH=12) revealed improved anodic passivity behavior compared to pure Mg for all the Mg-Y alloys. X-ray photoelectron spectroscopy (XPS) revealed that the improved passivity of Mg-Y was more related to the elemental oxidation state rather than the concentration of the surface components. To study the effect of Cl"- ion on the passivity behavior, anodic potentiodynamic and potentiostatic polarization were performed on Mg-17.9 at.% Y in alkaline (pH=12) NaCl electrolytes containing Cl"- ion in the concentration range from 0.00 to 0.50 M. The passive films formed in 0.01 M ...
This paper reports about in-situ corrosion studies on selected materials for long-term resistant high-level waste (HLW) packagings acting as a barrier in a rock salt repository. The materials (Ti 99.8-Pd, Hastelloy C4 and five iron-base materials) were investigated in heated boreholes in the Asse salt mine under simulated HLW disposal conditions prevailing in normal operation of repository and in certain accident scenarios. The experiments under normal operating conditions were performed at temperatures of 120 deg. C to 210 deg. C (vertical temperature profile in the boreholes) without and with gamma irradiation (3#centre dot#10"2 Gy/h, Co-60 source) within the framework of the German/US Brine Migration Test. In these experiments only small amounts of migrated brine inclusions (NaCl-rich) from the rock salt were present as corrosion medium. In the experiments carried out under simulated accident conditions with intrusion of larger amounts of NaCl brine into the HLW ...
To understand the effect of Mo-Nb additions on the electrochemical behavior of #beta#-titanium alloys in ambient temperature chloride solutions, characterization of the electrochemistry and passivity of a Ti-15Mo-3Al alloy (#beta#-21S) was undertaken. Both solution heat-treated (SHT) and peak-aged (PA) alloys exhibited passive anodic behavior in aerated and deaerated 0.6M NaCl, aerated and deaerated 0.6M NaCl adjusted to pH 1 with HCl, as well as aerated 5M HCl. X-ray photoelectron spectroscopy (XPS) performed after exposure to neutral 0.6M NaCl indicated that both PA and SHT #beta#-21S formed a predominantly TiO_2 film. Auger electron spectroscopy (AES) and cathodic kinetics suggest that the Mo and Nb alloying additions are incorporated into the oxide in amounts less than that found in the alloys. The predominance of the passivating TiO_2 may explain the similarity of the electrochemical behavior observed. However, in ...
Recent developments in the analysis of Mira atmosphere, the determination of the pulsation mode, the problem of mass loss, and the evolution of the Mira variables are covered. Model atmospheres for Mira variables, including the opacities of the molecules expected in very late M-type atmospheres are discussed. The pulsation constant for Omicron Ceti is evaluated using T(eff) = 2900 + or - 200 K, and it is concluded that Miras are fundamental mode pulsators. The importance of molecular opacity to the driving of mass loss is evaluated, and it is pointed out that the radiation pressure on molecules is not a major factor in driving mass loss from Mira. Mass loss is considered as a factor in the calculations of the periods for Mira variables. 30 refs.
A theory of the asymptotic functions for the case of many variables is presented. It is shown that the class F(R"N) of these generalized functions is closed in respect to the linear algebraic and analytic operations, multiplication as well as a set of linear and polynomial changes of the variables. The existence in F(R"N) of analogues (consistent with the linear operations) of the Schwartz distributions with point support is proved. In terms of these analogues, some formulae for singular products and changes of variables of the Dirac #delta#-function and its derivatives #delta#"("i")(x), x is an element of R"N, are given. (author). 14 refs.
Success in improving hydropower project efficiency has opened more global markets for variable-speed generator technology. Manufacturers continue to test the markets as the technology evolves. The potential of variable-speed application becomes evident considering that more than 150 pumped storage plants, with a combined capacity exceeding 100,000 MW, are in operation globally.
Based on proposed models for the tidal spin-up and magnetic braking of stars with a convective outer envelope, it is suggested that the rotation of secondaries in cataclysmic variables is not necessarily synchronized with the orbital revolution. This may provide an explanation for the observed large range in the mass transfer rate (at the same orbital period) of cataclysmic variables above the period gap. (author).
In this paper, we derive the moderate deviation principle for stationary sequences of bounded random variables with values in a Hilbert space. The conditions obtained are expressed in terms of martingale-type conditions. The main tools are martingale approximations and a new Hoeffding inequality for non adpated sequences of Hilbert-valued random variables. Applications to Cramer-Von Mises statistics, functions of linear processes and stable Markov chains are given.
This paper examines how robust economic, political, and demographic variables are related to water and air pollution. Employing Bayesian Averaging of Classical Estimates (BACE) for a cross section of 47 countries, 34 variables and 3 proxies for air and water pollution over a period from 1980 to 2000 we confirm the environmental Kuznets curve hypothesis and highlight the relevance of variables that are not directly related to production.
In recent years there has been a renewed interest in the treatment of quantum mechanics in terms of joint distribution functions, i.e. functions of momentum and position coordinates p and q. The author considers j.d.f. in the sense of classical probability theory of a stochastic variable. The j.d.f. is then interpreted as the probability that the variables p and q have certain values, the variables being considered as a property possessed by the object system. This formalism is used to provide a unified description of bradyons and tachyons. (Auth.).
The authors summarize EUVE's contribution to the study of the boundary layer emission of high accretion-rate nonmagnetic cataclysmic variables, especially the dwarf novae SS Cyg, U Gem, VW Hyi, and OY Car in outburst. They discuss the optical and EUV light curves of dwarf nova outbursts, the quasi-coherent oscillations of the EUV flux of SS Cyg, the EUV spectra of dwarf novae, and the future of EUV observations of cataclysmic variables.
Respiration and related physiologic variables in different tissues of Barytelphusa guerini and the respiration of this freshwater crab as a whole are closely synchronized in phase and in frequency along the circadian scale, in the face of large differences in circadian amplitude. A very close timing of most of the 36 variables examined in 2 separate circadian profiles and a modulation of some of these variables in added profiles as a function of lunar stage are clearly demonstrable, statistically significant and illustrative of time relations at 2 interacting frequencies. PMID:6745009
A methodology and hypothetical case study are presented for incorporation of uncertainty and variability into calculations of human health risk appropriate for regional, or basin-scale, groundwater management problems. Uncertainty in well water concentration is introduced through complex contaminant migration patterns in the subsurface. Variability is considered in parameters related to individual behavior patterns and biological effects and to groundwater extraction and distribution networks. A joint uncertainty and variability (JUV) analysis is used to generate a two-dimensional distribution or risk surface that spans both transport uncertainty as well as individual variability. Cuts in this distributional surface (fractiles of variability and percentiles of uncertainty) are presented and discussed. Comparisons with alternative approaches based upon deterministic transport models ...
A new technique has been developed for improving corrosion resistance on magnesium alloys. Specimens of AZ31 magnesium alloy were dipped into molten salt of NaBF{sub 4} at 723 K for various times, and then cooled, rinsed with water, and dried in air. Corrosion resistance in the surface treated specimens was evaluated by salt immersion test using 1% NaCl solution as a time for occurring filiform corrosion. On an un-treated AZ31 alloy, the time for starting the filiform corrosion was about 1.2 ks, while on the surface treated specimen, the time was prolonged into about 1300 ks. Moreover, the surface treated specimen showed corrosion resistance in low pH solutions, such as 1% HNO{sub 3} and HCl solutions. (orig.)
We have studied freshly prepared lysozyme solutions in heavy water for two NaCl concentrations as a function of temperature. Lysozyme solubilities in this solvent are determined by static light scattering. By small angle neutron scattering, we evidence that interactions between lysozyme molecules are characterized by a second virial coefficient A{sub 2} whether the solution is under-saturated or supersaturated. From the variation of A{sub 2} as a function of temperature we have evaluated the enthalpy corresponding to the interaction between lysozyme molecules. We show that the interactions between protein molecules are higher in heavy water than in light water. (authors). 13 refs., 3 figs.
An estimate of the undercounted electrostatic energy terms in local-density-functional total-energy calculations for nonmetallic systems with separated electron-hole pairs is used to derive a simplified correction to density-functional - theory band gaps. The correction is evaluated for Ne, Ar, Kr, LiF, NaCl, CsCl, MgO, CaS, BaS, C, AlP, and Si. The band-gap errors are reduced from 40-50% to 10-15% for most of the systems studied. Conduction-band corrections are shown to be nearly as large as valence-band corrections in free-electron-like semiconductors. 28 references, 1 figure.
The passive films formed on 316L stainless steel in various NaCl solutions have been investigated by capacitance measurements (Mott-Schottky). Pitting parameters have been determined using the galvano-kinetic polarisation method. The obtained results reveal the existence of a shallow and a deep donor level localised in the band gap of the semiconducting oxide film. These energy levels are due to iron ions in the tetrahedral and octahedral positions. It also appears that the participation of the deep donor level effects the electric field. The study developed allows us to compare characteristic parameters of the electronic structure of the passive film to those related to pitting susceptibility. (authors) 25 refs.
P-implantation (10"1"7 ions cm"-"2, 40 KeV) into 304 stainless steel (ss) has been carried out, and an amorphous surface alloy was formed. Polarization studies in deaerated 1N H_2SO_4+ 2% NaCl showed that P-implantation improved both the general and localized corrosion resistance of 304 ss. A comparative study has been carried out between the implanted and unimplanted steel to determine what influence P-implantation has upon the properties of the passive film formed 1N H_2SO_4. The influence of Cl ions on pre-formed passive films was also studied. RHEED, XPS and AES were used to evaluate the nature of the passive films formed in these studies.
P-implantation (10/sup 17/ ions cm/sup -2/, 40 KeV) into 304 stainless steel (ss) has been carried out, and an amorphous surface alloy was formed. Polarization studies in deaerated 1N H/sub 2/SO/sub 4/+ 2% NaCl showed that P-implantation improved both the general and localized corrosion resistance of 304 ss. A comparative study has been carried out between the implanted and unimplanted steel to determine what influence P-implantation has upon the properties of the passive film formed 1N H/sub 2/SO/sub 4/. The influence of Cl ions on pre-formed passive films was also studied. RHEED, XPS and AES were used to evaluate the nature of the passive films formed in these studies.
Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses. Physiological and biochemical parameters were assessed in the plant organs after 2?weeks of salt treatment with 25, 50, 75 and 100?mM NaCl. Results showed that, growth was reduced even by 25?mM, and salt effect was more pronounced in shoots (leaves and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K+ uptake, as well as an increase in Na+ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline conditions...
Abstract Phase-separation dynamics are investigated by SALS in aqueous MC solutions in the presence of 5% NaCl, promoted by a quench temperature. The observed scattering peak indicates that the phase separation occurs by the SD mechanism, leading to a bicontinuous structure. A semilog plot of I(q) against time in the early stage of SD gives a straight line, but the position of qmax varies; also, a Cahn-Hilliard plot indicates that diffusive processes dominate and the data can be described by linear CHC theory. Dapp shows a kinetic dependency on the quench temperature. The spinodal temperature of the sample is 41-C. In the late stages, S(q,t) collapses into a universally time-independent curve.
The dependence of the inhibiting action of some surface active organic substances (SAOS) on the pitting- formation potential epsilonsub(p) has been investigated for the steel Kh25T. The study has been performed by potentiostatic method using the H_2SO_4 0.1-n-solution doped by NaCl, Na_2SO_4, in the presence of SAOS of different classes. As epsilonsub(p) shifts in positive direction from +0.6 to +1.1 V, the inhibiting action of the SAOS series (o-oxyquinoline) increases gradually till some critical potential above which SAOS favour pitting destruction of steel. This phenomenon should be considered in anodic protection in SAOS-doped solutions.
Abstract Purpose: We investigated the effects of various rinsing and healing protocols on corneal wound repair and inflammation following alkali burn in rabbits. Methods: We conducted in vitro, in vivo and ex vivo studies. First, different rinse solutions were tested in vitro after incubation of ocular cells with methanol or NaOH. Cell viability was then assessed using the neutral red test (cytofluorometry). Second, NaOH was applied to rabbit corneas and associations of rinse solutions (NaCl 0.9% or controlled ionization marine solutions) with N-acetylcysteine or vegetable oils (from Calophyllum inophyllum and Aleurites moluccana) were tested in vivo. The regeneration of the corneal epithelium and the infiltration of inflammatory cells were evaluated using in vivo confocal microscopy and e...
The key factors of enzymatic lysis of cells are the interaction between the enzyme and the cell - catalytic and non-catalytic adsorption of enzyme on cell surface. Here, the studies of lysis of intact Escherichia coli cells by chicken egg white lysozyme were performed. It was found that the ionic strength has a dual effect onto the system. On the one hand, the desorption constant of the enzyme increases with the increase of the solution ionic strength, which results in a better enzyme performance. On the other hand, due to the higher osmosis, the cell lysis rate decreases with the increasing of ionic strength of the system. It was found that pH 8.6 and 30mM NaCl are optimal conditions for lysis of E. coli cells by lysozyme.
An effect of load conditions on Corrosion Fatigue Crack Propagation (CFCP) behavior of High Performance Steel (HPS) under seawater environment was investigated. Fatigue crack propagation tests under several load conditions including stress ratio and load frequency were conducted in air and 3.5% NaCl solution environments. Corrosion/fatigue ratio factor, C/F, particularly was defined to analyze the effect of such conditions. As shown in the results, a decrease of load ratio and frequency leads to an increase of C/F factor. Consequently, under lower loading frequency and stress ratio, the seawater condition causes much more significant effect on CFCP behavior of HPS.
The surface films formed on type 316LN stainless steels (SS) with different nitrogen contents, during potentiodynamic polarization in acidified 1 M NaCl solution, were characterized by Laser Raman Spectroscopy (LRS). LRS confirmed the presence of oxides and oxychlorides of iron and chromium, hydrated chlorides and nitrates in the film. Raman mapping showed increasing nitrate content in the film with increasing nitrogen content. The film on the uncorroded material showed the presence of chromium and molybdenum oxides. The improvement in pitting corrosion resistance of type 316LN SS with increasing nitrogen content was attributed to increased amount of nitrates in the passive film.
The surface films formed on type 316LN stainless steels (SS) with different nitrogen contents, during potentiodynamic polarization in acidified 1 M NaCl solution, were characterized by Laser Raman Spectroscopy (LRS). LRS confirmed the presence of oxides and oxychlorides of iron and chromium, hydrated chlorides and nitrates in the film. Raman mapping showed increasing nitrate content in the film with increasing nitrogen content. The film on the uncorroded material showed the presence of chromium and molybdenum oxides. The improvement in pitting corrosion resistance of type 316LN SS with increasing nitrogen content was attributed to increased amount of nitrates in the passive film.
The response regulator protein is a core element of two-component signaling pathway. In this study, we investigated functions of BRRG-1 of Botrytis cinerea, a gene that encodes a putative response regulator protein, which is homologous to Rrg-1 in Neurospora crassa. The BRRG-1 gene deletion mutant ?Brrg1-62 was unable to produce conidia. The mutant showed increased sensitivity to osmotic stress mediated by NaCl and KCl, and to oxidative stress generated by H2O2. Additionally, the mutant was more sensitive to the fungicides iprodione, fludioxonil, and triadimefon than the parental strain. Western-blot analysis showed that the Bos-2 protein, the putative downstream component of Brrg-1, was not phosphorylated in the ?Brrg1-62. Real-time polymerase chain reaction assays showed that expression ...
The electrochemical behaviour and fracture morphology of homogenized and sensitized type SAE 304 stainless steel U bent specimens, in 3% NaCl solution, at pH=2.0 and pH=7.0 both at room temperature and 100"0C was studied. Polarization curves, galvanostatic and potentiostatic experiments were run. It could be observed that high temperature and low pH favour transgranular cracking and longer sensitization times lower fracture time and tend to give rise to intergranular fracture. Light sensitization can produce transgranular cracking even at room temperature, when the homogenized alloy does not present stress-corrosion cracking for the same condition. (Author).
This paper aims to study fundamentally the impacts of membrane properties on the reactive dye removal from dye/salt mixtures by nanofiltration membranes. To begin with, two types of nanofiltration membranes of similar pore size, namely asymmetric cellulose acetate membrane and thin-film composite polyamide membrane were fabricated, and their key physical, chemical and performance properties were characterized. After that, these resultant membranes were employed to perform dye removal experiments with aqueous solutions of reactive black 5 and NaCl under different operational parameters. The dye removal rate and steady permeate flux were determined and correlated with the measured membrane properties. It was found that there were significant differences between the dye removal performances o...
Passive films were formed on a high purity Fe-23 Cr alloy in acid sulfate solutions in the presence and absence of chloride ion. The resulting film composition was investigated by Auger depth profiling. The passivated samples were exposed to a 1M NaCl solution at a constant potential slightly above the critical pitting potential, and the current-time transient was measured in order to compare the relative stability of the different films. The results obtained suggest that the formation conditions influence the chloride content of the passive film and the breakdown behavior. Passive films formed in the presence of chloride contain and are slightly less stable towards breakdown. No chloride was found in films formed in sulfate and subsequently exposed to chloride well below the pitting potential.
In this investigation, a forward osmosis (FO) dewatering process is evaluated as an alternative for dewatering orange peel press liquor. The press liquor is concentrated by removing water via osmosis into a concentrated ''draw solution'' across a polymeric cellulose acetate membrane. For this investigation, the draw solution consisted of sodium chloride at two different concentrations (2M and 4M). These draw solutions were used to concentrate synthetic press liquor. Concentration factors up to 3.7 resulted when using a 4M NaCl draw solution and the synthetic press liquor. Also during this investigation, fouling behavior was observed and the mechanisms of fouling elucidated through a systematic approach. This approach identified the key components of the press liquor that were primarily res...
Studies were carried out on the decolorization of textile azo dyes by newly isolated halophilic and halotolerant bacteria. Among the 27 strains of halophilic and halotolerant bacteria isolated from effluents of textile industries, three showed remarkable ability in decolorizing the widely utilized azo dyes. Phenotypic characterization and phylogenetic analysis based on 16S rDNA sequence comparisons indicate that these strains belonged to the genus Halomonas. The three strains were able to decolorize azo dyes in a wide range of NaCl concentration (up to 20%w/v), temperature (25-40degreeC), and pH (5-11) after 4 days of incubation in static culture. They could decolorize the mixture of dyes as well as pure dyes. These strains also readily grew in and decolorized the high concentrations of dy...
Abstract Background- Cyclosporine is used for treatment of transplanted patients and for immune-mediated diseases. Cyclosporine is known to cause a combination of metabolic side effects including hypertension, hyperkalemia, hypercalciuria and hypomagnesemia. These side effects except for hypomagnesemia are the cardinal features of familial hyperkalemia and hypertension (FHHt), also called pseudohypoaldosteronism type II (PHA II). FHHt is caused by mutations in the kinases WNK1 and WNK4 resulting in an increase in renal Na-Cl cotransporter (NCC) apical distribution and function. Therefore, we studied whether cyclosporine-s metabolic side effects are mediated by WNK4 and NCC. Design- Sprague-Dawley (SD) rats were treated by cyclosporine 25-mg-kg-1 subcutaneously for 14-days. Blood pressure, ...
There are reported the results of corrosion resistance investigation of aluminium bronzes, containing about 8 and 10% of aluminium and modifying quantities of zirconium. The tests of corrosion resistance were carried out in synthetic seawater, in 3% NaCl aqueous solution and in 10% H_2SO_4 aqueous solution, with reference to industrial bronze BA93 (CuAl9Fe3). The bronzes were tested in an annealed, hardened, tempered state and after plastic hot working. The conclusion is that corrosion resistance of aluminium bronzes, especially against selective corrosion, depends more on material structure, resulted form heat treatment, than on chemical composition. (author). 6 refs, 8 figs, 6 tabs.
To the best of our knowledge, this is the first report on the chemical and microbial properties of traditional Iranian fish sauce, mahyaveh. Fish sauce samples used in this study originated from five different locations in the Southern part of Iran. The pH of mahyaveh samples from different locations was in the range of 4.89-7.55 and NaCl concentration was in the range of 7.48-17.1%. The overall mean of TVB-N in all the samples tested was 3098 mg/kg. Histamine, with the overall mean of 2662 mg/kg, was found to be the main biogenic amine in the Iranian fish sauce. The high histamine content can be related to the high levels of bacterial count especially enterobacteriaceae (overall mean of 3.41 log cfu/g) and lactic acid bacteria (overall mean of 4.13 log cfu/g) in this product. Spermidine w...
In this work passive films formed in AISI 304 stainless steel were envisaged as semiconductors and studied by means of photoelectrochemistry and Mott-Schottky plots. The passive films were potentiostatically formed at different potentials (0.2-0.8V) in a basic borate/boric acid solution without and with addition of NaCl (0.5 and 1g/l) and at various temperatures in the range 8-60"oC. The influence of these parameters on the photocurrent, quantum efficiency, bandgap energy and density of charge carriers was determined. The results show that the experimental conditions at which the films are formed influence the semiconductive properties of the film, which seem to be related to the higher or lower stability of the film. An Arrhenius type of relationship was also found between the density of charge carriers and temperature, leading to the determination of an activation energy. (author) 13 refs., 7 figs.
It is generally known that a number of metallic glasses have excellent corrosion resistance in a variety of chemically hostile environments. Consequently, the use of laser cladding to coat a massive crystalline material such as aluminium with a layer of a metallic glass has obvious advantages. In this paper, the authors will show that the formation of a predominantly amorphous layer of Zr_6_0Al_1_5NI_2_5 alloy by laser processing is possible, if the obstacles to amorphization are overcome. In addition, evidence of the excellent corrosion resistance of this alloy in a NaCl solution will be given. A comparative study of the corrosion behavior of this amorphous alloy with pure aluminium and Al-Cr alloy will be done, in order to complete previous studies of laser processed coatings of aluminum substrates.
A new technique was proposed in order to improve poor corrosion resistance in magnesium. That is, magnesium hydroxide film was formed on the surface of 3 N-Mg by artificial corrosion in 1% MgCl{sub 2} solution for 3.6 ks, which followed by oxidation at 673 K for 3.6 ks in air. Corrosion resistance was evaluated by salt immersion tests in 1% NaCl solution under in situ laser microscopic observations. Bubble evolution, which occurred immediately at the beginning of the immersion test in the case of non-treated specimen, was suppressed by the process. And also, formation of filiform corrosion was suppressed for about 3.6 ks, which occurred at 180 s in the non-treated specimen. (orig.)
Dimensional variability studies and published dimensional variability standards have been used by the foundry industry for years as an indicator of the casting process` ability to produce uniform parts. These studies are an extremely useful tool in the continuous ``dimensional dialogue`` between foundries and customers. The nature of these studies, and of the current tolerancing systems used by casting designers, leaves room for some misinterpretation and misuse of these study results. This paper contains two important discussions. The first part explains exactly what these studies represent. Following this is a brief explanation on dimensional and geometric tolerances and how they communicate dimensional requirements.
This research investigates the impact of national culture and several institutional factors on the safety performance of society and establishes statistically significant relationships between those variables. As expected, the research results reveal that some cultural variables such as uncertainty avoidance, gender orientation and institutional variables such as the degree of law avoidance can directly influence the safety performance of the society. The findings also support the inverted u-curve (Safety Kuznet curve) hypothesis indicating even if we expect a negative trend at the beginning stage of industrialization, we can expect a positive trend in safety performance as their income level continues to improve beyond a certain point.
In this talk, we explore the feasibility of quantum computation using continuous-variable systems by means of local measurements only. In the first part of the talk, we will identify crucial limitations that arise when starting from Gaussian cluster states. This is done by resorting to a Gaussian projected entangled pair picture as well as to notions of continuous-variable quantum repeater networks. In the second part, we look at instances in which these limitations can be overcome, and how suitable encodings of qubits in oscillators and feasible non-Gaussian resource states give rise to universal schemes for quantum computing.
Creep properties of modified 9 Cr-1 Mo steel, an alloy significantly improved in elevated-temperature strength over 2 1/4 Cr-1 Mo and other similar alloys, are presented here. Data are primarily on material in the normalized and tempered condition. Effects of variables such as isothermal annealing treatment, cold work, normalizing temperature, tempering temperature, notch, and biaxial stress state have also been examined. Data analysis and comparisons have shown that modified 9 Cr-1 Mo alloy is very insensitive in response to several material variables, heat treatments, and specimen design variables.
Background and ObjectivePulsed dye laser (PDL) treatment of cutaneous vascular lesions is associated with variable and unpredictable efficacy. Thus, alternative treatment...Full Text Available
The proteolytic activities of a disintegrin and metalloproteinase (ADAM); a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), and matrix metalloproteinase (MMP) families play important...Full Text Available
The fatigue life variability of the #alpha#+#beta# titanium alloy, Ti-6Al-2Sn-4Zr-6Mo increased with decreasing stress level. The variability in life was found to be due to segregation of lives due to two failure mechanisms. A bimodal cumulative distribution model was shown to accurately describe the combined failure modes. The nominal failure processes for the two regimes were similar, with crack nucleation occurring in equiaxed #alpha#p particles, irrespective of life or stress level. However the variability in life was not controlled by the size of the crack-nucleating #alpha#p, but rather by the ability of the material to distribute deformation and avoid early crack nucleation.
the southern Arabian Gulf region left its signature on the heterogeneous aerosol .... Arabian Gulf region, since large differences in ? may be caused by ...
... Variable, Alimentos mal enlatados, especialmente verduras enlatadas en el hogar; pescado fermentado, papas asadas en papel de aluminio, ajo envasado. ...
Brains are usually described as input/output systems: they transform sensory input into motor output. However, the motor output of brains (behavior) is notoriously variable, even under identical sensory...Full Text Available
A central composite design was employed to optimize the extraction of pectin with citric acid. The independent variables were citric acid concentration (0.086-2.91% w/v) and extraction time (17-102min). The combined effect of these variables on the degree of esterification was investigated. Results have shown that the generated regression models adequately explained the data variation and significantly represented the actual relationship between the independent variables and the responses. Besides that, the citric acid concentration was the most important factor to affect the degree of esterification, as it exerted a significant influence on the dependent variable. Lower citric acid concentration increased the pectin degree of esterification. The surface response showed the relationships b...
In this paper we present a complete solution to the problem of multifractal analysis of multiple ergodic averages in the case of symbolic dynamics for functions of two variables depending on the first coordinate.
Worldwide century-long forest hydrologic research has documented that deforestation and forestation (i.e. reforestation and afforestation) can have variable ...
Jul 25, 2011 ... Koji Mukai's Bibliography. Invited Reviews. Mukai, K. 1994, "ASCA PV Phase Observations of Cataclysmic Variables," in "New Horizon of X-ray ...
According to classical concepts of physiologic control, healthy systems are self-regulated to reduce variability and maintain physiologic constancy. Contrary to the predictions of homeostasis, however,...Full Text Available
Background and AimsAnnonaceae are one of the largest families of Magnoliales. This study investigates the comparative floral development of 15 species to understand the basis for...Full Text Available
Statistically based experimental designs were applied to screen and optimize the bioleaching of spent hydrocracking catalyst by Penicillium simplicissimum. Eleven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design. Four significant variables (pulp density, sucrose, NaNO"3, and yeast extract concentrations) were selected for the optimization studies. The combined effect of these variables on metal bioleaching was studied using a central composite design (CCD). Second-order polynomials were established to identify the relationship between the recovery percent of the metals and the four significant variables. The optimal values of the variables for maximum metals bioleaching were as follows: pulp density (4.0%, w/v), sucrose (90g/L), NaNO"3 (2...
Knowledge on environmental variability and how it is affected by disturbances is crucial for understanding patterns of biodiversity and determining adequate conservation strategies. The aim of this study is to assess environmental variability in patches undergoing post-fire vegetation recovery, identifying trends of change and their relevant drivers. We particularly evaluate: the value of three spectral indices derived from Landsat satellite data [Normalized Burn Ratio (NBR), Normalized Difference Vegetation Index (NDVI) and Wetness Component of the Tasseled Cap Transformation (TCW)] for describing secondary succession; the effectiveness of three metrics (diversity, evenness and richness) as indicators of patch variability; and how thematic resolution can affect the perception of environme...
Wildlife Refuge, CA Rare and endangered endemic plants Diana Anderson Northern Arizona University Geomorphology Kathryn Thomas USGS, Flagstaff, AZ Vegetation dynamics John...
Climate variability greatly affects animals through direct and indirect effects. Animals with slow reproductive adaptation to ecological changes such as large mammals are likely to have evolved mechanisms to anticipate early such impacts of climate variability on the environment. One of the adaptive mechanisms between reproductive costs and benefits in mammals affects parental investment through biases in sex ratio. Deer might be likely to show an early detection of climate variability because conception takes place in early autumn, but the main raising cost in deer concerns lactation, which takes place at the end of the following spring. The aim of this paper is to assess whether there is a relationship between global indices of climate variability such as El Ni?o-Southern Oscillation (EN...
The study of genetic variability within natural populations of pathogens may provide insight into their evolution and pathogenesis. We used a Mycobacterium tuberculosis high-density...Full Text Available
The study has analysed the effects of various factors on hydroelectric power generation potential to include climate change/variability, water demand, and installation of proposed hydroelectric power schemes in the Zambezi River Basin. An assessment of historical (1970?2000) power potential in relation to climate change/variability at existing hydro electric power schemes(Cahora Bassa, Kariba, Kafue Gorge and Itezhi-Tezhi) in the Zambezi River Basin was conducted. The correlation of hydroelectric power potential with climate change/variability aimed at observing the link and extent of influence of the latter on the former was investigated. In order to predict the future outlook of hydro electric power potential, General Circulation Models (GCM) were used to generate projected precipitation...
measure meteorological variables and bulk water temper- ature. The locations of the buoys are given in Table 1. TB2 and TB3 were moved slightly farther south ...
We construct the Baxter Q-operator and the representation of the Separated Variables (SoV) for the homogeneous open SL(2,R) spin chain. Applying the diagrammatical approach, we calculate Sklyanin's integration measure in the separated variables and obtain the solution to the spectral problem for the model in terms of the eigenvalues of the Q-operator. We show that the transition kernel to the SoV representation is factorized into the product of certain operators each depending on a single separated variable. As a consequence, it has a universal pyramid-like form that has been already observed for various quantum integrable models such as periodic Toda chain, closed SL(2,R) and SL(2,C) spin chains.
We obtain an elegant and useful description of the dynamics of Szekeres dust models (in their full generality) by means of "quasi--local" scalar variables constructed by suitable integral distributions that can be interpreted as weighed proper volume averages of the local covariant scalars. In terms of these variables, the field equations and basic physical and geometric quantities are formally identical to their corresponding expressions in the spherically symmetric LTB dust models. Since we can map every Szekeres model to a unique LTB model, rigorous results valid for the latter models can be readily generalized to a non--spherical Szekeres geometry. The new variables lead naturally to an initial value formulation in which all scalars are expressed as scaling laws in terms of their values at an arbitrary initial space slice. These variables also yield a significant simplification of numerical work, ...
Methanosarcina thermophila, a nonmarine methanogenic archaebacterium, can grow in a range of saline concentrations. At less than 0.4 M NaCl, Ms. thermophila accumulated glutamate in response to increasing osmotic stress. At greater than 0.4 M NaCl, this organism synthesized a modified #beta#-amino acid that was identified as N"v"a"r"-"e"p"s"i"l"o"n-acetyl-#beta#-lysine by NMR spectroscopy and ion-exchange HPLC. This #beta#-amino acid derivative accumulated to high intracellular concentrations (up to 0.6 M) in Ms. thermophila and in another methanogen examined - Methanogenium cariaci, a marine species. The compound has features that are characteristic of a compatible solute: it is neutrally charged at physiological pH and it is highly soluble. When the cells were grown in the presence of exogenous glycine betaine, a physiological pH and it is highly soluble. When the cells were grown in the presence of exogenous glycine betaine, a physiological ...
High molecular weight DNA from pleroceroid larvae of the tapeworm Spirometra mansonoides was purified from isolated nuclei by conventional techniques. The DNA so isolated has a melting temperature (Tm) of 87 degrees C and a guanine plus cytosine (G/C) content of 44%. 5-Methyl cytosine could not be detected in plerocercoid DNA by HPLC analysis of DNA hydrolysates, by radiolabeling 5'-termini of MspI digests with polynucleotide kinase, or by comparing restriction patterns generated by MspI and HpaII. Renaturation kinetics demonstrated that the genome of S. mansonoides contains repetitive as well as single copy sequences and has a genome size estimated at approx. 1.6 X 10(9) bp. Hybridization was carried out between plerocercoid DNA and cDNAs for human beta-actin, alpha-tubulin and growth hormone (hGH). Rationale for this analysis was based on known homologies among actin and tubulin genes in numerous species and on apparent similarities between hGH and a plerocercoid growth factor that ...
The potentiodynamic polarization measurement of 254SMO stainless steel (UNS 31254) was conducted in 3.5% NaCl solutions with pH ranging from 0.1 to 5. The results indicated that this stainless steel offered excellent pitting corrosion resistance in corrosive environments. Further, it also exhibited various features on the polarization curves in different pH solutions. The electrochemical constant-potential passivation treatment performed at different pH followed by XPS analysis revealed that the primary constituents of the outermost layer of the passive films formed in the weak (pH 5) and strong (pH 0.8) acid solutions are iron oxides and Cr{sub 2}O{sub 3} and Cr(OH){sub 3}, respectively. Molybdenum oxides, primarily in the six-valence state, existed in the outermost layer of the passive film. Only very weak signals corresponding to that of nickel oxides were detected in the film formed in the weak acid (pH 5) solution. The ICP-MS analyses indicated selective ...
The potentiodynamic polarization measurement of 254SMO stainless steel (UNS 31254) was conducted in 3.5% NaCl solutions with pH ranging from 0.1 to 5. The results indicated that this stainless steel offered excellent pitting corrosion resistance in corrosive environments. Further, it also exhibited various features on the polarization curves in different pH solutions. The electrochemical constant-potential passivation treatment performed at different pH followed by XPS analysis revealed that the primary constituents of the outermost layer of the passive films formed in the weak (pH 5) and strong (pH 0.8) acid solutions are iron oxides and Cr_2O_3 and Cr(OH)_3, respectively. Molybdenum oxides, primarily in the six-valence state, existed in the outermost layer of the passive film. Only very weak signals corresponding to that of nickel oxides were detected in the film formed in the weak acid (pH 5) solution. The ICP-MS analyses indicated selective dissolution of a ...
After being pre-plated a zinc layer, an amorphous Al-Mn alloy coating was applied onto the surface of AZ31B magnesium alloy with a bath of molten salts. Then the corrosion performance of the coated magnesium alloy was examined in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the single Zn layer was active in the test solution with a high corrosion rate while the Al-Mn alloy coating could effectively protect AZ31B magnesium alloy from corrosion in the solution. The high corrosion resistance of Al-Mn alloy coating was ascribed to an intact and stable passive film formed on the coating. The performances of the passive film on Al-Mn alloy were further investigated by Mott-Schottky curve and X-ray photoelectron spectroscopy (XPS) analysis. It was confirmed that the passive film exhibited n-type semiconducting behavior in 3.5% NaCl solution with a carrier density two ...
Synthesis of silver nanoparticles based on a polyol process and variable frequency microwave (VFM) was investigated. Comparing to a thermal method, the reaction by VFM radiation was much faster. The effects of silver nitrate concentration, poly(N-vinylpyrrolidone) (PVP) concentration, reaction time and reaction temperature were studied. It was found that the higher concentration of silver nitrate, longer reaction time and higher temperature increased the particle size while the higher concentration of PVP decreased the particle size.
A physical model of free-electron laser (FEL) amplifier with variable-parameter wiggler magnets for one-dimensional numerical simulation is presented and a numerical example is given. The wiggler parameters, efficiency of energy conversion between electron beam and laser field, laser intensity, phase-space distributions and energy spectrum of electrons are computed. The period of synchronous oscillation and saturation value of laser intensity agree with estimated one.
In the case of large capacity steam turbines the conventional nozzle group control is, for mechanical and thermodynamic reasons, diminishing more and more in importance in favour of variable pressure control. A design for constant-pressure operation as an alternative to nozzle group control is described; this demonstrates a series of important advantages compared with the latter. (orig.).
This book contains the Proceedings of the Conference on Climate and Water under the following groupings: Impacts of climatic variability and change-resulting from the changes in hydrological variables; Aquatic environment; Terrestrial environment; Coastal zones and navigation; Urban and industrial water supply and drainage; Energy production; Intropogenic changes of climate and water management problems; Flood potential; Irrigation and land drainage.
This book contains the Proceedings of the Conference on Climate and Water under the following groupings: Impacts of climatic variability and change-resulting from the changes in hydrological variables; Aquatic environment; Terrestrial environment; Coastal zones and navigation; Urban and industrial water supply and drainage; Energy production; Intropogenic changes of climate and water management problems; Flood potential; Irrigation and land drainage.
Two major developments have given impetus to wider adoption of variable-speed turbine/generators in hydroelectric plants, both essentially environmental: (1) the need for stream-bed stability below river dams, and (2) the need to minimize fish damage. Also, the need to stabilize pumped-storage and generating efficiencies to match extreme changes in head levels has been a driving force. Variable-speed operation in hydro applications is relatively new to North America. In other parts of the world, it has been used in pumped-storage plants since 1971. In the US, and increasing potential exists for variable-speed hydro, considering the 30 pumped-storage plants already in operation and several river plants struggling with high head fluctuations--including four at stations operated by the Bonneville Power Administration. Several modifications to hydro-plant hardware and operating procedures are actively being considered at ...
The effect of fetal distress on the neonatal brain was investigated by neonatal CT brain scan, FHR monitoring and mode of delivery. This study involved 11 cases of full term vertex delivery in which FHR was recorded by fetal direct ECG during the second stage labor. All infants weighed 2,500 g or more. FHR monitoring was evaluated by Hon's classification. Neonatal brain edema was evaluated by cranial CT histgraphic analysis (Nakada's method). 1) Subdural hemorrhage was noted in 6 of 7 infants delivered by vacuum extraction or fundal pressure (Kristeller's method). 2) Intracranial hemorrhage was demonstrated in all of 3 infants with 5-min. Apgar score 7 or less. 3) Two cases with prolonged bradycardia and no variability had intraventricular or intracerebral hemorrhage which resulted in severe central nervous system damage. 4) The degree of neonatal brain edema correlated with 5-min. Apgar score. 5) One case with prolonged bradycardia and ...
The effect of fetal distress on the neonatal brain was investigated by neonatal CT brain scan, FHR monitoring and mode of delivery. This study involved 11 cases of full term vertex delivery in which FHR was recorded by fetal direct ECG during the second stage labor. All infants weighed 2,500 g or more. FHR monitoring was evaluated by Hon's classification. Neonatal brain edema was evaluated by cranial CT histgraphic analysis (Nakada's method). 1) Subdural hemorrhage was noted in 6 of 7 infants delivered by vacuum extraction or fundal pressure (Kristeller's method). 2) Intracranial hemorrhage was demonstrated in all of 3 infants with 5-min. Apgar score 7 or less. 3) Two cases with prolonged bradycardia and no variability had intraventricular or intracerebral hemorrhage which resulted in severe central nervous system damage. 4) The degree of neonatal brain edema correlated with 5-min. Apgar score. 5) One case with prolonged bradycardia and no ...
Lateral and vertical variabilities in the bulk and mechanical properties of silicic volcanic tuff at the potential nuclear waste repository site in Yucca Mountain, NV have been evaluated. Laboratory measurements have been performed on tuff specimens recovered from boreholes located to support the design of the Exploratory Studies Facility/North Ramp. The data include dry and saturated bulk densities, average grain density, porosity, compressional and shear wave velocities, elastic moduli, and compressional and tensional fracture strengths. Data from eight boreholes aligned in a northwest-southeast direction have been collected under the required quality assurance program. Three boreholes have penetrated the potential repository horizon. The information collected provides for an accurate appraisal of the variability of rock properties in the vicinity of the boreholes. As expected, there is substantial variability in the bulk ...
To assess the variability and systematic differences in polyp measurements on optical colonoscopy and CT colonography. Gastroenterologists measured 51 polyps by visual estimation, forceps comparison and linear probe. CT colonography observers randomly assessed polyp size two-dimensionally (abdominal and intermediate window) and three-dimensionally (manually and semi-automatically). Linear mixed models were used to assess the variability and systematic differences between CT colonography and optical colonoscopy techniques. The variability of forceps and linear probe measurements was comparable and both showed less variability than measurement by visual assessment. Measurements by linear probe were 0.7 mm smaller than measurements by visual assessment or by forceps. The variability of all CT colonography techniques was lower than for measurements by forceps or visual assessment and ...
In this article, we studied the effects of variable viscosity and thermal conductivity on an unsteady two-dimensional laminar flow of a viscous incompressible conducting fluid past a semi-infinite vertical porous moving plate taking into account the effect of a magnetic field in the presence of variable suction. The fluid viscosity is assumed to vary as an inverse linear function of temperature but the thermal conductivity is assumed to vary as a linear function of temperature. It is assumed that the porous plate moves with a constant velocity in the direction of fluid flow, and the free stream velocity follows the exponentially increasing small perturbation law. The governing equations for the flow are transformed into a system of nonlinear ordinary differential equations by perturbation ...
Diet overlap and niche breadth are well-known species traits from trophic ecology that can assist in explaining how species interact and coexist as well as the ecological mechanisms that influence biodiversity. In the present study, we analyzed the relationships between these trophic variables and indicators of resource availability with some attributes of fish assemblages (species richness, Shannon diversity index, evenness, density and individual body size). The physical and chemical characteristics of the biotopes (topography, water quality and conservation of slopes) were examined to identify possible patterns. Monthly sampling using electrofishing was conducted in 2003 along five streams located in the Cuiab? River watershed. The relationships between environmental variables and attri...
An automotive powertrain includes a conventional piston engine, a continuously variable ratio transmission, an engine speed sensor and a feedback control system. The control system adjusts both the transmission ratio and the throttle valve in the engine carburetor or fuel metering system in response to the position of the accelerator pedal and in response to the crankshaft speed as measured by the engine sensor. The transmission provides extreme overdrive gear ratios which allow the engine to be operated at wide open throttle even during moderate cruising, and, in addition, the engine carburetor or fuel metering system is calibrated to deliver to the engine a stoichiometric air-fuel mixture which is combined, before combustion, with a special proportion of recirculated exhaust gas. As a result of extensive wide open throttle engine operation with the above mentioned intake charge composition, combustion variables are optimized to produce ...
Abstract In this paper, a new predictive model that can forecast the performance of a vertical axis wind turbine (VAWT) is presented. The new model includes four primary variables (rotor velocity, wind velocity, air density, and turbine power output) as well as five geometrical variables (rotor radius, turbine height, turbine width, stator spacing, and stator angle). These variables are reduced to include the power coefficient (Cp) and tip speed ratio (TSR). A power coefficient correlation for a novel VAWT (called a Zephyr Vertical axis Wind Turbine (ZVWT)) is developed. The turbine is an adaptation of the Savonius design. The new correlation can predict the turbine's performance for altered stator geometry and varying operating conditions. Numerical simulations with a rotating reference f...
This paper analyses Italian interregional migration flows. The approach taken is to decompose labour mobility flows into short distance and long distance migration and to model the effects of economic variables, social capital and quality of life variables, and amenity variables, on the mobility behaviour of individuals. We estimate these different types of migration flows using a negative binomial model, augmented with instruments to control for potential endogeneity issues. Our findings demonstrate that long distance migration reflects a disequilibrium model of migration whereas short distance migration largely reflects an equilibrium model of migration. As such, attempts to model interregional migration in general will be mis-specified as the simultaneously-operating underlying mobility...
The unavoidable irreversible losses of power in a heat engine are found to be of quantum origin. Following thermodynamic tradition a model quantum heat engine operating by the Otto cycle is analyzed. The working medium of the model is composed of an ensemble of harmonic oscillators. A link is established between the quantum observables and thermodynamical variables based on the concept of canonical invariance. These quantum variables are sufficient to determine the state of the system and with it all thermodynamical variables. Conditions for optimal work, power and entropy production show that maximum power is a compromise between the quasistatic limit of adiabatic following on the compression and expansion branches and a sudden limit of very short time allocation to these branches. At high temperatures and quasistatic operating conditions the efficiency at maximum power coincides with the endoreversible result. The optimal ...
Various SST indices in the Indo-Pacific region have been proposed in the literature in light of a long-range seasonal forecasting of the Indian Summer Monsoon (ISM). However, the dynamics associated with these different indices have never been compared in detail. To this end, the present work re-examines the variabilities of ISM rainfall, onset and withdrawal dates at interannual timescales and explores their relationships with El Ni?o-Southern Oscillation (ENSO) and various modes of coupled variability in the Indian Ocean. Based on recent findings in the literature, five SST indices are considered here: Ni?o3.4 SST index in December?January both preceding [Nino(?1)] and following the ISM [Nino(0)], South East Indian Ocean (SEIO) SST in February?March, the Indian Ocean Basin (IOB) mode in ...
The primary objective of batch data as trajectory alignment (or synchronization) is to standardize the data sampling per batch according to the evolution of the process, and secondarily to homogenize the samples per run. The use of an indicator variable performs both objectives well. Two examples from the pharmaceutical sector are discussed to illustrate the different ways to deal with uneven samples across batches and across variables in the same batch. Since trajectory alignment requires large time investment, a simple triage approach is proposed to assess the need to analyze the dynamics of a given process and hence perform alignment. The presented examples are representative of a broad variety of batch processes that are operated by recipe in the pharmaceutical sector. In our experienc...
Abstract Mammalian teeth exhibit incremental structures representing successive forming fronts of enamel at varying time scales, including a short daily increment called a cross striation and a long period called a stria of Retzius, the latter of which, in humans, occurs on average every 8-9 days. The number of daily increments between striae is called the repeat interval, which is the same period as that required to form one increment of bone, i.e. the lamella, the fundamental - if not archetypal - unit of bone. Lamellae of known formation time nevertheless vary in width, and thus their measures provide time-calibrated growth rate variability. We measured growth rate variability for as many as 6 years of continuously forming primary incremental lamellar bone from midshaft femur histologic...
An interesting line of research is the investigation of the laws of random variables known as Dirichlet means. However, there is not much information on interrelationships between different Dirichlet means. Here, we introduce two distributional operations, one of which consists of multiplying a mean functional by an independent beta random variable, the other being an operation involving an exponential change of measure. These operations identify relationships between different means and their densities. This allows one to use the often considerable analytic work on obtaining results for one Dirichlet mean to obtain results for an entire family of otherwise seemingly unrelated Dirichlet means. Additionally, it allows one to obtain explicit densities for the related class of random variables that have generalized gamma convolution distributions and the finite-dimensional distribution of their associated L\\'{e}vy processes. ...
Purpose Nonpoint sources (NPS) pollution has been an important cause for water quality impairment worldwide. To take the temporal variations of both NPS pollution and in-stream attenuation into consideration, an inverse modeling approach and the load duration curve (LDC) method were combined for variable nutrient total maximum daily load (TMDL) development. Methods Water quality and hydrological parameters were monitored monthly along the ChangLe River system in 2004?2008. The catchment NPS export load (EL) and TMDL for total nitrogen (TN) were estimated by the inverse format of an existing stream nutrient transport equation. The LDC method was used to describe the variability of EL, TMDL, requiring load (RLR) and percent (the ratio between the RLR and the EL, RPR) reduction, and then to s...
The central engine of Gamma Ray Bursts is hidden from direct probing with photons mainly due to the high densities involved. Inferences on their properties are thus made from their cosmological setting, energetics, low-energy counterparts and variability. If GRBs are powered by hypercritical accretion onto compact objects, on small spatial scales the flow will exhibit fluctuations, which could in principle be reflected in the power output of the central engine and ultimately in the high energy prompt emission. Here we address this issue by characterizing the variability in neutrino cooled accretion flows through local shearing box simulations with magnetic fields, and then convolving them on a global scale with large scale dynamical simulations of accretion disks. The resulting signature is characteristic, and sensitive to the details of the cooling mechanism, providing in principle a discriminant for GRB central engine properties.
Multi-millennial climate changes were relatively minor over the mid-late Holocene in the British Isles, because orbitally forced insolation changes were smaller than those at higher latitudes. Centennial climate variability is thus likely to have exerted a greater influence on the environment and human society of the region. Proxy-climate records from the British Isles covering the last 4500years are assembled and re-evaluated with the aim of identifying centennial climate variability reflected by multi-proxy indicators. The proxies include bog oak populations, peatland surface wetness, flooding episodes from fluvial deposits, speleothem annual band width and oxygen isotopes, chironomids from lake sediments and sand and dune deposition. Most proxies reflect water balance rather than temper...
This paper presents a study on Manasbal lake, which is one of the high altitude lakes in the Kashmir Valley, India. Eighteen water samples were analysed for major ions and trace elements to assess the variability of water quality of the lake for various purposes. Geostatistics, the theory of regionalized variables, was then used to enhance the dataset and estimate some missing spatial values. Results indicated that the concentration of major ions in the water samples in winter was higher than in summer. The scatter diagrams suggested the dominance of alkaline earths over the alkali elements. Three types of water were identified in the lake that are referred to as Ca?HCO3, Mg?HCO3 and hybrid types. The lake water was found to be controlled by rock?water interaction with carbonate lithology ...
This paper focuses on a factorial-based design strategy. The approach provides an efficient and statistically reliable means for assessing the influence of multivariable effects. It is applied to the detection and evaluation of damage in impacted composite sandwich panels. The experimental results obtained from this test strategy are utilized to form an empirical response function. The resulting polynomial relates damage area to residual compression strength at values of independent variables for which testing did not occur. The response function also identifies nonlinear interaction effects of key variabes that cannot be easily ascertained by traditional single-variable test strategies. Independent variables evaluated include core thickness, number of face sheet plys and impact energy. The methodology presented allows the designer to predict with more confidence the damage tolerance of a composite material component, and ...
A variable gene delivery system has been developed based on conjugating chitosan to biotin through a functionalized poly(ethylene glycol) (PEG) spacer, which can be used to further bind different molecules on the outer layer of a polymer/DNA complex by streptavidin (SA)-biotin linkage. In this study, TAT-conjugated SA was used as the model molecule to prove the conjugation function of the prepared complex. In addition, low-molecular-weight poly(ethyleneimine) (PEI) was added into the polymer/DNA complex to increase the transfection efficiency. The results of the luciferase assay show that the transfection efficiency of the prepared complex was significantly correlated with the amount of PEI and was further enhanced when TAT was conjugated to the complex by SA-biotin linkage. Considered to have negligible cytotoxic effects, the variable gene delivery complex prepared in this study would be of considerable potential as carriers for in vitro ...
Experiments based on a 23 central composite full factorial design were carried out in 200-ml stainless-steel containers to study the pretreatment, with dilute sulfuric acid, of a sugarcane bagasse sample obtained from a local sugar?alcohol mill. The independent variables selected for study were temperature, varied from 112.5?C to 157.5?C, residence time, varied from 5.0 to 35.0 min, and sulfuric acid concentration, varied from 0.0% to 3.0% (w/v). Bagasse loading of 15% (w/w) was used in all experiments. Statistical analysis of the experimental results showed that all three independent variables significantly influenced the response variables, namely the bagasse solubilization, efficiency of xylose recovery in the hemicellulosic hydrolysate, efficiency of cellulose enzymatic saccharificatio...
The parmbsc0 force field was applied to study in detail the binding of netropsin, at a salt concentration of 0.28M Na^+, to the minor groove of an 8-mer (5'CCAATTGG)2 DNA duplex forming a netropsin.DNA complex which previously has been characterized by X-ray crystallography, albeit with the use of closely related DNA duplexes. The X-ray structure revealed that the terminal guanidinium and amidinium groups of netropsin interact with the extreme ends of the palindromic AATT sequence of the receptor DNA. The parmbsc0 parameters of B-DNA and AMBER v9 parameters of netropsin generated a stable 6ns molecular dynamics (MD) trajectory for a 1:1 class I binding motif of this complex. Trajectory analysis for the salt and hydration effects on the binding of netropsin to the 8-mer DNA duplex revealed ...
Heating during frictional sliding is a major component of the energy budget of earthquakes and represents a potential weakening mechanism. It is therefore important to investigate how heat dissipates during sliding on simulated faults. We present results from laboratory friction experiments where a halite (NaCl) slider held under constant load is dragged across a coarse substrate. Surface evolution and frictional resistance are recorded. Heat emission at the sliding surface is monitored using an infra-red camera. We demonstrate a link between plastic deformations of halite and enhanced heating characterized by transient localized heat spots. When sand 'gouge' is added to the interface, heating is more diffuse. Importantly, when strong asperities concentrate deformation, significantly more heat is produced locally. In natural faults such regions could be nucleation patches for melt production and hence potentially initiate weakening during earthquakes at much ...
Six species having characteristics of plants with the C(4) dicarboxylic photosynthetic pathway, Echinochloa utilis L. Ohwi et Yabuno (Japanese millet), Cynodon dactylon L. (Bermuda grass), Kyllinga brevifolia Rottb., Amaranthus tricolor L. cv. Early splendour, Kochia childsii Hort., and Portulaca grandiflora Hook (rose moss), responded decisively to 0.1 milliequivalent per liter NaCl supplied to their culture solutions initially containing less than 0.08 microequivalent per liter Na. Chlorosis and necrosis occurred in leaves of plants not receiving sodium. Portulaca failed to set flower in the sodium-deficient cultures. Under similar conditions Poa pratensis L. (Kentucky blue grass) having characteristics of the C(3) photosynthetic pathway made normal growth and did not respond to the addition of sodium. It is concluded from these results and previously reported work that sodium is generally essential for species having the C(4) pathway but not for species with the ...
The effect of temperature (60-280{sup o}C) on the properties of the oxide films formed on Alloy 800 in 0.1 M NaCl and 0.1 M Na{sub 2}SO{sub 4} aqueous solutions was studied by in situ AC impedance spectroscopy and polarization in the Fe(CN{sub 6}){sup -3}/Fe(CN){sub 6}{sup -4} redox system. The anodic behavior under the same experimental conditions was examined by potentiodynamic polarization techniques. In both solutions the passive film was found to become more porous, and hence less protective, with increasing temperature. However, at temperatures above 150{sup o}C, the loss of film protectiveness is more pronounced in chloride solutions, in which pitting occurs. Pitting morphology was found to be strongly temperature dependent: isolated and deep pits were found up to 200{sup o}C whereas at higher temperatures a broad, shallow and more generalized type of attack was detected. No effect of temperature on the defect structure of the semiconductor oxide film was ...
Six species having characteristics of plants with the C4 dicarboxylic photosynthetic pathway, Echinochloa utilis L. Ohwi et Yabuno (Japanese millet), Cynodon dactylon L. (Bermuda grass), Kyllinga brevifolia Rottb., Amaranthus tricolor L. cv. Early splendour, Kochia childsii Hort., and Portulaca grandiflora Hook (rose moss), responded decisively to 0.1 milliequivalent per liter NaCl supplied to their culture solutions initially containing less than 0.08 microequivalent per liter Na. Chlorosis and necrosis occurred in leaves of plants not receiving sodium. Portulaca failed to set flower in the sodium-deficient cultures. Under similar conditions Poa pratensis L. (Kentucky blue grass) having characteristics of the C3 photosynthetic pathway made normal growth and did not respond to the addition of sodium. It is concluded from these results and previously reported work that sodium is generally essential for species having the C4 pathway but not for species with the C3 ...
Several thin film composite nanofiltration membranes have been prepared by spin coating a sulfonated poly(ether ether ketone) solution on a polyethersulfone support, followed by thermal treatment. The most optimal developed nanofiltration membrane shows a clean water permeance of ~4.5Lm^-^2h^-^1bar^-^1 and a molecular weight cut off (MWCO) of ~500gmol^-^1. No irreversible changes in membrane performance have been observed after prolonged exposure (up to several weeks) of this membrane to solutions with a pH in the range 0-14. Compared to Desal-5-DK, the developed membrane displays a similar water permeance and a higher NaCl retention. In comparison to commercially available pH stable membranes, MPF-34 and NP030P, it reveals a higher water permeance. Permeance and MWCO analysis at varying p...
This paper deals with the characterization of passive films formed on stainless steel (26% Cr and 0 to 3%Mo). The influence of the applied passivation potential and the effect of molybdenum additions to steel upon the composition profiles of passive films formed in an aqueous NaCl solution (3.5% at pH 2.5) are studied. The technique involved is Auger electron spectroscopy combined with ion sputtering. Some electrochemical techniques have been used in conjunction. A quantitative approach of the Auger spectra during the progressive removal of the passive film is described. The peak-to-peak height of the Auger lines are treated in order to yield the atomic fraction of the various elements present in a given subsurface layer. The analytical study of the film by electron spectroscopy indicates that molybdenum plays a part at the metal-oxide interface where this element acts on the chromium diffusion process. This phenomenon, which depends on the imposed potential, may ...
The results of X-ray and neutron diffraction experiments on molten alkali halides in which some data of our experiments by X-ray diffraction such as those of molten LiCl, NaCl, KCl, LiBr and KBr are included were summarized. The first peak positions in the radial distribution function in molten alkali halides by X-ray or neutron diffraction experiments are always longer than those by computer simulations and the differences of 0.1 -- 0.3 A exceed the experimental error. It seems to be due to the deformation of the electron shell. In the computer simulation, the shell model which has the spherical deformation was expected to have a closer value of the first peak position to the experimental one than the rigid ion model by taking the polarization of ions. However, no change in the first peak position was found. Therefore, the non-spherical deformation of electron shell at the point where ions are in contact with each other has to be taken into account. The neutron ...
The results of X-ray and neutron diffraction experiments on molten alkali halides in which some data of our experiments by X-ray diffraction such as those of molten LiCl, NaCl, KCl, LiBr and KBr are included were summarized. The first peak positions in the radial distribution function in molten alkali halides by X-ray or neutron diffraction experiments are always longer than those by computer simulations and the differences of 0.1 -- 0.3 A exceed the experimental error. It seems to be due to the deformation of the electron shell. In the computer simulation, the shell model which has the spherical deformation was expected to have more closer value of the first peak position to the experimental one than the rigid ion model by taking the polarization of ions. However, no change in the first peak position was found. Therefore, the non-spherical deformation of electron shell at the point where ions are in contact with each other has to be taken into account. The neutron ...
In recent years intergranular stress corrosion cracking has occurred world-wide in the shrink-fitted discs of low pressure turbine rotors made of low alloy steels. Only in a few cases steam impurities such as NaOH, Na_2CO_3, Na_2SO_4, H_2S or NaCl, which initiate SCC, could be found. To clarify the SCC-behaviour experiments on turbine disc steels with different chemical compositions and yield strength were performed in high purity water. The results show, that chemical composition has no effect on the crack initiation. Under high purity water conditions no crack initiation due to stress corrosion cracking is observed on the steel with a yield strength of 850 N/mm"2. On the steel with a yield strength of 1250 N/mm"2 which is not used in service, crack initiation occurs in pure water. But if sharp cracks already exist, crack propagation occurs in both cases. The investigations showed, that stress corrosion cracking of turbine discs can be prevented by a good water ...
Using a series of polycations synthesized by atom transfer radical polymerization (ATRP), we investigate the effects of the polymer charge density and hydrophobicity on salt-induced interdiffusion of polymer layers within polyelectrolyte multilayer (PEM) films. Polycations with two distinct hydrophobicities and various quaternization degrees (QPDMA and QPDEA) were derived from parent polymers of matched molecular weights poly(2-(dimethylamino)ethyl methacrylate) (PDMA) and poly(2-(diethylamino)ethyl methacrylate) (PDEA) by quaternization with either methyl or ethyl sulfate. Multilayers of these polycations with polystyrene sulfonate (PSS) were assembled in low-salt conditions, and annealed in NaCl solutions to induce layer intermixing. As revealed by neutron reflectometry (NR), polycations with lower charge density resulted in a faster decay of film structure with distance from the substrate. Interestingly, when comparing polymer mobility in QPDEA/PSS and QPDMA/PSS ...
The performance of larger than bench scale ion exchange systems is evaluated by using solutions containing trace amounts of "1"3"7Cs, "8"5Kr, and "1"3"1I, and large amounts of either NaCl or Na_2HPO_4, H_3BO_3, and LiOH. The significant finding in this study is that the empirical rules of ionic selectivity of strong acid cation and strong base anion resins were followed by all ionic species, even though concentrations of some macrocomponents were nearly 10"6 times those of trace components. Other results of possible importance are the correlation between the instantaneous decontamination factor (DF) and the efficiency of column exchange capacity utilization, and the concept of time average decontamination factor (anti DF). The plot of anti DF vs. feed throughput will serve as a guide in determining when the feed should be discontinued in order to achieve a desired anti DF. Both of these correlations are derived from the breakthrough curves.
The behavior of lead in the graphite furnace during the individual steps of the temperature program was investigated by means of /sup 203/Pb as a radiotracer. The matrix systems include HCl and HNO/sub 3/ solutions, 1% NaCl solution, blood, serum, urine, and the solid samples bovine liver and orchard leaves. Without matrix modificaton, a pyrolysis temperature of up to 500/sup 0/C can be used for all samples. Significant stabilization effects can be achieved in the preatomization steps by using NH/sub 4/H/sub 2/PO/sub 4/ and ammonia as matrix modifiers and by addition of hydrogen to the flowing argon gas. It was found that the use of a L'vov platform also helps to eliminate the matrix effects. With respect to lead stabilization and elimination of matrix effects, optimum experimental conditions are achieved by simultaneous use of a L'vov platform and NH/sub 4/H/sub 2/PO/sub 4/ as the matrix modifier. 34 references, 5 figures, 1 table.
The behavior of lead in the graphite furnace during the individual steps of the temperature program was investigated by means of "2"0"3Pb as a radiotracer. The matrix systems include HCl and HNO_3 solutions, 1% NaCl solution, blood, serum, urine, and the solid samples bovine liver and orchard leaves. Without matrix modificaton, a pyrolysis temperature of up to 500"0C can be used for all samples. Significant stabilization effects can be achieved in the preatomization steps by using NH_4H_2PO_4 and ammonia as matrix modifiers and by addition of hydrogen to the flowing argon gas. It was found that the use of a L'vov platform also helps to eliminate the matrix effects. With respect to lead stabilization and elimination of matrix effects, optimum experimental conditions are achieved by simultaneous use of a L'vov platform and NH_4H_2PO_4 as the matrix modifier. 34 references, 5 figures, 1 table.
The "6"2Zn-"6"2Cu generator system is one of the few which yield a pure positron emitting daughter. The authors have developed a method for the preparation of this generator system following 32 MeV #alpha# particle bombardment of nickel targets. The chemical processing involves two stages: first a hydrous zirconium oxide column is used at pH 4-5 to separate the zinc and copper activities produced in the target nickel, and secondly, a conventional anion exchange column is used to retain the "6"2Zn and remove all copper activities in 2M HCl. This column serves as the "6"2Cu generator which will yield pure "6"2Cu repeatedly, free from "6"2Zn and other impurities, in a mixture of HCl and NaCl. A method is outlined also to obtain a solution of "6"2Zn using the hydrous zirconium oxide (HZO) column. "6"1Cu can be prepared as a by-product in the above procedure, but a method for the preparation of "6"1Cu alone using an 18 MeV #alpha# particle beam on a nickel target and ...
The corrosion behaviour of friction stir welded (FSW) joints of AA 5083 has been compared to that of MIG welded joints. Pitting and stress corrosion cracking (SCC) resistance in 3.5% NaCl + 0.3 g/l H{sub 2}O{sub 2} and in EXCO (4 M KCl + 0.5 M KNO{sub 3} + 0.1 M HNO{sub 3}) solutions has been determined at 25 C. SCC susceptibility was evaluated by slow strain rate tests (SSRT), at a strain rate of 1 x 10{sup -6}s{sup -1}. Welds obtained by FSW technique showed a higher corrosion resistance in EXCO solution and a lower pitting tendency than the base alloy. Electrochemical measurements (corrosion potential measurements, polarization curves recording) evidenced that FSW weld was cathodic to base alloy. FSW joints were not susceptible to SCC in both test solutions, whereas MIG joints cracked in both solutions. (orig.)
Passive films formed on mild steel in aqueous 8.6 mM NaCl solutions (pH 8), containing either MoO{sub 4}{sup 2-} or NO{sub 2}{sup -}, have been studied with X-ray photoelectron spectroscopy. For either anion these films are {approx}5 nm deep, and the primary chemical state of iron is Fe{sup 3+}. Following exposure to MoO{sub 4}{sup 2-}, the film consists of a sub-layer ({approx}4.1 nm) composed largely of ferric oxide/hydroxide, overlaid by Fe{sub 2}(MoO{sub 4}){sub 3} ({approx}0.6 nm). As regards NO{sub 2}{sup -}, spectra are consistent with the film being closely related to {gamma}-Fe{sub 2}O{sub 3}. Furthermore, a reduction product of NO{sub 2}{sup -}, potentially N{sub 2}, is present, displaying a depth profile comparable to that of molybdate.
This paper presents the first results on formation and study of structure and properties of micro- and nanocomposite combined coatings. By means of modeling the deposition processes (deposition conditions, current density-discharge, plasma composition and density, voltage) we formed the three-layer nanocomposite coatings of Ti-Al-N/Ti-N/Al_2O_3. The coating composition, structure and properties were studied using physical and nuclear-physical methods. The Rutherford proton and helium ion backscattering, scanning electron microscopy with microanalysis, grazing incidence X-ray diffraction, as well as nanohardness tests (hardness) were used. Measurements of wear resistance and corrosion resistance in NaCl, HCl and H_2SO_4 solutions were also performed. For testing mechanical properties such characteristics of layered structures as hardness H, elastic modulus E: H"3/E"2 etc. were measured. It is demonstrated that the formed three-layer nanocomposite coatings have ...
Fatigue-crack growth in air and in aqueous 3.5-percent NaCl as well as fracture toughness are evaluated for the metastable beta-titanium alloy Ti-3Al-8V-6Cr-4Mo-4Zr in various microstructural conditions. Two solution heat treatments (SHT), 800 C and 927 C, were chosen to produce two different grain sizes. Approximately 20 vol pct unrecrystallized beta grains remained after SHT at the lower temperature. Yield stresses were 895 and 850 MPa, respectively. Both simplex and duplex aging treatments were performed for both grain sizes to vary the distribution of alpha precipitates while keeping the yield stress in the range of 1075-1220 MPa for all aged conditions. Unaged material exhibits significantly higher fracture toughness levels than aged material. The unrecrystallized regions were associated with a loss in ductility and toughness. 21 refs.
A study was undertaken of the effect of monovalent cations (Li/sup +/, Na/sup +/, K/sup +/) on the dielectric constant (epsilon) of the water-lipid interface of unilamellar phosphatidylcholine (PC) vesicles, i.e., the ester carbonyl oxygen region of the PC molecules or the neighborhood of the oxygen atoms of the phosphorylcholine moiety. epsilon was determined by reacting the free radical 1,1-diphenyl-2-picrylhydrazyl with ..cap alpha..-tocopherol incorporated in the lipid vesicles. The results are consistent with a decrease of epsilon (LiCl: 35.5 to 29.5; NaCl: 34 to 29; KCl: 33 to 29) as the concentration of the salts in the solvent media increases from 0.025 to 0.5 M. These effects can be rationalized in terms of dielectric saturation at the water-lipid interface brought about by ion-induced local electric fields. In the unilamellar PC vesicles the effect of the ions on epsilon follows the sequence K/sup +/ > Na/sup +/ > Li/sup +/ which contrasts ...
A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground stress with a resolution of about 25 psi, or 2.5% at 1000 psi. Downhole ...
Iofetamine HCI {sup 123}I is the generic name for the hydrochloride salt of N-isopropyl-p-iodoamphetamine labeled with {sup 123}I, commonly called IMP. Iofetamine HCI {sup 123}I is prepared by isotopic exchange with [{sup 123}I]Nal and is formulated in isotonic aqueous NaCl solution containing 1 mCi/ml iofetamine HCI I 123, 0.15 mg/ml iofetamine HCI carrier, and phosphate buffer for pH control. The radiochemical purity is >97%, and the product is stable for more than 24 hours; the commercial product distributed today is prepared with high purity {sup 123}I with >98% radionuclidic purity. Two radioiodinated agents have seen significant clinical application for functional brain imaging: iofetamine HCI (IMP) (1) and N,N,N{prime}-trimethyl-N{prime}-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3-propanediamine HIPDM (2). lofetamine HCI {sup 123}I is commercially available in the United States, Europe, and Japan. Although their primary use is for functional brain imaging, ...
The photon rupture method, by which oxide film and metal are removed by focused pulsed Nd-YAG laser beam irradiation, was applied to form artificial micro-pits in Zn-5 mass% Al alloy-coated steel. The zinc alloy-coated layer was removed by pulsed laser irradiation treatment for about one second in a neutral buffer solution with NaCl. The rest potential transient with the laser treatment was measured. In the early stage of the laser treatment the rest potential of zinc alloy-coated steel changed to the negative direction immediately after every irradiation of a laser pulse and then returned to the previous value. However, after the steel substrate was exposed to the solution, the rest potential moved to the positive direction immediately after every irradiation of a laser pulse and then returned to the previous value. The amplitude and duration of the potential change after the laser irradiation increased with repetition of laser irradiation, related to the pit ...
A series of experiments have been conducted on AISI 5140 low alloy steel using a hollow cathode discharge-assisted plasma nitriding apparatus with the aim of elucidating the role of substrate bias voltages in plasma nitriding process. For comparison, some samples were nitrided with applied substrate bias (-50 V) while other samples were nitrided at floating potential. Treatments were carried out in NH{sub 3} atmosphere of 150 Pa at temperatures ranging from 450 {sup o}C to 550 {sup o}C for 2 h, 4 h, and 6 h. The nitrided samples were characterized by optical microscopy, X-ray diffraction and micro-hardness measurement. The corrosion behaviors were evaluated using anodic polarization tests in 3.5% NaCl solution. The results showed that the microstructure and phase constituents of the nitride layers were strongly influenced by the bias voltages. It was also demonstrated that the better corrosion resistance with a thicker nitrided layer was obtained on the biased ...
A series of experiments have been conducted on AISI 5140 low alloy steel using a hollow cathode discharge-assisted plasma nitriding apparatus with the aim of elucidating the role of substrate bias voltages in plasma nitriding process. For comparison, some samples were nitrided with applied substrate bias (-50 V) while other samples were nitrided at floating potential. Treatments were carried out in NH_3 atmosphere of 150 Pa at temperatures ranging from 450 "oC to 550 "oC for 2 h, 4 h, and 6 h. The nitrided samples were characterized by optical microscopy, X-ray diffraction and micro-hardness measurement. The corrosion behaviors were evaluated using anodic polarization tests in 3.5% NaCl solution. The results showed that the microstructure and phase constituents of the nitride layers were strongly influenced by the bias voltages. It was also demonstrated that the better corrosion resistance with a thicker nitrided layer was obtained on the biased sample.
Homozygous transgenic cotton (Gossypium hirsutum L.) plants that accumulated glycinebetaine (GB) in larger quantities were more tolerant to salt than wild-type (WT) plants. Four transgenic lines, namely 1, 3, 4, and 5, accumulated significantly higher levels of GB than WT plants did both before and after salt stress. At 175 and 275?mM NaCl, seeds of all the transgenic lines germinated earlier and recorded a higher final germination percentage, and the seedlings grew better, than those of the WT. Under salt stress, all the lines showed some characteristic features of salt tolerance, such as higher leaf relative water content (RWC), higher photosynthesis, better osmotic adjustment (OA), lower percentage of ion leakage, and lower peroxidation of the lipid membrane. Levels of endogenous GB in ...
Introduction: We have evaluated the ability of a semi-automated, optomotor reflex method to assess drug-induced visual dysfunction, in albino and pigmented rats and mice. Methods: Male Han Wistar (HW) and Long Evans (LE) rats and mice (CD-1 and C57BL/6) were tested in a chamber formed by 4 computer monitors displaying a rotating vertical grating, to elicit head-tracking movements. The highest visible grating frequency was taken as the threshold of visual acuity, in cycles per degree (c/d). Animals received an intravenous infusion of either sodium iodate (50mg/kg) or 0.9% w/v NaCl (aq). They were tested 2h later, then re-tested daily for a further 3days. The time course of the effect was assessed in HW rats over a 6-week period, including electron microscopy, and immunohistochemical analysi...
At room pressure and temperature the system EuOsub(1-x)Nsub(x) has two solid-solubility ranges, each with the NaCl structure: for 0 =< x =< 0.30 the system is ferromagnetic and semiconducting above the Curie temperature; for 0.92 =< x <1 it is metallic. Conductivity and Seebeck voltages indicate intrinsic behaviour above 310 K with an energy gap that decreases with increasing x for 0 =< x =< 0.30. Magnetic susceptibilities are consistent with 4f"6 configurations at x europium ions per molecule and a ferromagnetic Curie temperature Tsub(C) that increases with x. Low-temperature transport measurements were made only for 0.20 =< x =< 0.30: a minimum in the electrical conductivity, approximately 30 K above Tsub(C) correlates well with the onset of an anomalous low-temperature crystal contraction and with deviations from a Curie-Weiss law typical of short-range magnetic order. Below Tsub(C) there is a metal-to-semiconductor transition similar to ...
The combined effects of environment, yield strength and stress state on the cracking susceptibility of beta-extruded Ti-6Al-6V-2Sn have been examined. At a constant yield strength and under plane strain conditions, the stress intensity required for slow crack propagation decreased as the severity of the environment increased, i.e., from laboratory air to 3.5% NaCl. Furthermore, the crack propagation rates were a function of both stress intensity, and environmental severity. Although the fracture toughness and threshold stress intensities for slow crack growth generally decreased with increasing yield strength, aging, which resulted in the precipitation of ordered Ti3Al particles in the primary alpha phase, tended to accentuate the susceptibility of this alloy to sustained load/stress corrosion cracking. Finally, at constant yield strength, the sustained load cracking threshold stress intensity was a function of stress state.
The effect of dissolved oxygen and copper on denting corrosion at 280/sup 0/C in solutions of NaCl at pH 9 with ammonia was investigated using a packed tube/support plate crevice in a laboratory simulation. The onset of corrosion was detected with a hydrogen analyzer sensitive to 0.2 ppB. In the absence of copper, rapidly rising hydrogen concentrations were detected only when the product of the chloride and oxygen concentrations were detected only when the product of the chloride and oxygen concentrations in the boiler-water exceeded 25 (ppM)/sup 2/, but at these high concentrations, unheated low-carbon steel surfaces in the system were as sensitive to corrosion as the heated crevice. When copper metal was present in the feed system, corrosion of the heated crevice occurred in the absence of oxygen, provided the copper had previously been exposed to dissolved oxygen. Dosing hydrazine into the feedwater eventually suppressed the ability of copper to initiate ...
Samples of 316L stainless steel, Vitalium and Ti6A14V titanium alloy have been implanted with doses of 1.5, 3, and 4.5 x 10"1"7 Si"+/cm"2. Transmission electron microscopy shows that during ion implantation amorphous layers are formed. When samples of titanium alloy were implanted with a dose of 0.5 x 10"1"7 Si"+/cm"2, the implanted layer consisted of a dispersion of fine silicide crystallites instead of being amorphous. The corrosion resistance was analyzed by electrochemical techniques in 0.9% NaCl at the temperature of 37 C. The increase of corrosion resistance has been observed as a result of structural modifications of the surface layer. (author). 7 refs, 4 tabs.
Phillips Petroleum Company recently completed a microbial selective plugging (MSP) pilot at the North Burbank Unit (NBU), Shidler, Oklahoma. Nutrients were selected for the pilot that could stimulate indigenous microflora in the reservoir brine to grow and produce exopolymer. It was found that soluble corn starch polymers (e.g., maltodextrins) stimulated the indigenous bacteria to produce exopolymer, whereas simple sugars (e.g., glucose and sucrose), as well as complex media (e.g., molasses and Nutrient Broth), did not. Injection of maltodextrin into rock cores in the presence of indigenous NBU bacteria resulted in stable permeability reductions (> 90%) across the entire length, while injection of glucose resulted only in face plugging. In addition, it was found that organic phosphate esters (OPE) served as a preferable source of phosphorus for the indigenous bacteria, since orthophosphates and condensed phosphates precipitated in NBU brine at reservoir temperature (45{degrees}C). ...
Previous corrosion studies identified the materials Hastelloy C4, Ti 99.8-Pd, and carbon steels as promising for the manufacture of long-lived high-level waste containers that could act as an engineered barrier in a rock-salt repository. Here, the efficiency of the corrosion-resistant concept using surface-welded Hastelloy C4 as corrosion protection of carbon steel containers is compared with the corrosion-allowance concept using unalloyed or low-alloyed steels. The materials are examined in three disposal relevant brines (two rich in MgCl_2, one rich in NaCl) at 150 C. The results indicate that welded Hastelloy C4 is highly resistant to corrosion in the NaCl-rich brine. In the presence of sulfides or MgCl_2-rich brines, however, severe pitting corrosion occurs. The three steels investigated are resistant to pitting corrosion in all brines, and their general corrosion rates imply corrosion allowances acceptable for thick-walled containers. In view of these results, ...
Results from four chemical-equilibrium computer programs, REDEQL.EPAK, GEOCHEM, WATEQF, and SENECA2, have been compared with experimental solubility data for some simple systems of interest with geothermal brines. Seven test cases involving solubilities of CaCO/sub 3/, amorphous SiO/sub 2/, CaSO/sub 4/, and BaSO/sub 4/ at various temperatures from 25 to 300/sup 0/C and in NaCl or HCl solutions of 0 to 4 molal have been examined. Significant differences between calculated results and experimental data occurred in some cases. These differences were traced to inaccuracies in free-energy or equilibrium-constant data and in activity coefficients used by the programs. Although currently available chemical-equilibrium programs can give reasonable results for these calculations, considerable care must be taken in the selection of free-energy data and methods of calculating activity coefficients.
Chelating tendencies of several biologically important compounds viz. glycocyamine (GCN: N-amidino-aminoethanoic acid) taurine (TRN: 2-aminoethanesulphonic acid) and pyridoxal [PDL: 3-hydroxy-5-(hydroxymethyl)-2-methyl-pyridine-4-carbaldehyde] have been examined by pH-metric titration technique in their binary complex formation with copper(II) and uranyl(VI) ions. The work has further been extended to investigating the ternary complex formation involving 2.2'-bipyridine. 1,10-phenanthroline or nitrilotriacetic acid as a primary and TRN and PDL as secondary ligands. All the experiments were carried out at 25"0C and at an ionic strength of 0.1M (NaCl0_4) in aqueous or 50% (v/v) aqueous-ethanol medium according to the suitability of the experimental conditions. Stabilities of ternary complexes as compared to those of the corresponding binary complexes of the secondary ligands have also been discussed. (author).
To improve adherent properties of electrogalvanized steel (EGS) to polymeric topcoats, the surfaces of EGS were modified by polyelectrolyte-modified zinc phosphating solution. The electrochemical reaction between phosphating solution and EGS led to the complete coverage with fully grown hopeite crystals after only 5 sec treatment, thereby improving adhesion to topcoating and providing protection of EGS against corrosion. To evaluate the ability of polyphenylene sulfide (PPS) polyaryl thermoplastic coatings to protect zinc phosphate (Zn{center_dot}Ph)treated steels from corrosion in a wet, harsh environment ( 1.0 wt % H{sub 2}SO{sub 4}, 3.0 wt % NaCl and 96.0 wt % water at temperatures from 25{degrees} to 200{degree}C), we exposed them in an autoclave to attempt heating-cooling cyclic fatigue tests (1 cycle = 12 hr at 200{degrees}C + 12 hr at 25{degrees}C) up to 90 times. The major chemical reaction at the interface between the PPS and Zn in the Zn-Ph layer during ...
We analyzed the effect of short-term water deficits at different periods of sunflower (Helianthus annuus L.) leaf development on the spatial and temporal patterns of tissue expansion...Full Text Available
Effector proteins expressed in the esophageal gland cells of cyst nematodes are delivered into plant cells through a hollow, protrusible stylet. Although evidence indicates that effector proteins function...Full Text Available
BackgroundTransposons, i.e. transposable elements (TEs), are the major internal spontaneous mutation agents for the variability of eukaryotic genomes. To address the general issue...Full Text Available
Expressions for the spatial moments and macrodispersion tensor for sorbing solutes in heterogeneous formations were presented using a probabilistic model of a fluid residence time coupled with the particle position analysis. The fluid residence time was defined as a fraction of the actual time during which the particle stayed in the mobile fluid phase of the aquifer. The fluid residence time is a random variable whose variability comes as a result of the non-equilibrium sorption properties. The sorbing solute was assumed to be governed with first-order linear kinetics. The closed-form expressions were based on the stationarity in the kinetic process and on the first-order approximation in the hydraulic conductivity field and in the fluid residence time. The non-equilibrium effects were presented as a function of the spatial variability in hydraulic conductivity and temporal variability in the fluid ...
The paralysis-by-analysis phenomenon, i.e., attending to the execution of one's movement impairs performance, has gathered a lot of attention over recent years (see Wulf, 2007,...Full Text Available
Activation-induced deaminase (AID) initiates somatic hypermutation, gene conversion and class switch recombination by deaminating variable and switch region DNA cytidines to uridines. AID is predominantly...Full Text Available
Intraindividual variability of measurements of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), nicotine, cotinine, and r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene...Full Text Available
A previous report of high levels of members of the domain Archaea in Antarctic coastal waters prompted us to investigate the ecology of Antarctic planktonic prokaryotes. rRNA hybridization...Full Text Available
BackgroundSynonymous sites are freer to vary because of redundancy in genetic code. Messenger RNA secondary structure restricts this freedom, as revealed by previous findings in...Full Text Available
Dependent variables in research on problem behavior typically are based on measures of response repetition, but these measures may be problematic when behavior poses high risk or when its occurrence...Full Text Available
IntroductionHealth information on the Internet undergoes no quality control at the stage of production, thus its quality is highly variable, making it difficult...Full Text Available
Information from the Health Assessment Questionnaire (HAQ) is used to identify which variables measured in 1981 successfully predict the severity of disease in 1989 and the eight year change in severity...Full Text Available
Dissecting the genes involved in complex traits can be confounded by multiple factors, including extensive epistatic interactions among genes, the involvement of epigenetic regulators, and the variable...Full Text Available
BackgroundAn earlier study showed that a week of yoga practice was useful in stress management after a natural calamity. Due to heavy rain and a rift on the banks of the Kosi river,...Full Text Available
The highly variable and intermittent pollutant concentrations and flowrates associated with wet-weather events in combined sewersheds necessitates the use of storage-treatment systems to control pollution.An optimized combined-sewer-overflow (CSO) control system requires a manage...
Using the POLISH instrument, I am unable to reproduce the large-amplitude polarimetric observations of Berdyugina et al. (2008) to the >99.99% confidence level. I observe no significant polarimetric variability in the HD 189733 system, and the upper limit to variability from the exoplanet is Delta_P < 7.9 x 10^(-5) with 99% confidence in the 400 nm to 675 nm wavelength range. Berdyugina et al. (2008) report polarized, scattered light from the atmosphere of the HD 189733b hot Jupiter with an amplitude of two parts in 10^4. Such a large amplitude is over an order of magnitude larger than expected given a geometric albedo similar to other hot Jupiters. However, my non-detection of polarimetric variability phase-locked to the orbital period of the exoplanet, and the lack of any significant variability, shows that the polarimetric modulation reported by Berdyugina et al. (2008) cannot be due to the ...
The effect of spatial auditory information on a listener's ability to detect, identify, and monitor multiple simultaneous speech signals was evaluated using virtual audio technology. Factorial combinations of three variables - the number of localized spee...
The sequence-dependent structural variability and conformational dynamics of DNA play pivotal roles in many biological milieus, such as in the site-specific binding of transcription factors to target...Full Text Available
The sequences of the internal transcribed spacer (ITS) ribosomal DNA (rDNA) domain data obtained by restriction fragment length polymorphism analysis with 18S rDNA and fingerprinting (M13) for clinical...Full Text Available
Despite the demonstrated clinical efficacy of CD20 monoclonal antibody (mAb) for lymphoma therapy, the in vivo mechanisms of tumor depletion remain controversial and variable. To identify the molecular...Full Text Available
Study objectiveThe study aim was to improve our understanding of the relationships between contextual socioeconomic characteristics and coronary heart disease (CHD)...Full Text Available
Simulations with a regional chemical transport model show that anthropogenic emissions of volatile organic compounds and nitrogen oxides (NOx = NO + NO2) lead to a dramatic diurnal...Full Text Available
ObjectiveTo develop consistent variable names and a common database structure for the data elements in the International Spinal Cord Injury (SCI) Data Sets.Full Text Available
Random forest (RF) analysis of genetic data does not require specification of the mode of inheritance, and provides measures of variable importance that incorporate interaction effects. In this paper...Full Text Available
Although humans vary in their response to chemicals, comprehensive measures of susceptibility have generally not been incorporated into human risk assessment. The U.S. EPA dose-response-based risk assessments...Full Text Available
In this review we attempt to reconstruct the evolutionary history of hominin life history from extant and fossil evidence. We utilize demographic life history theory and distinguish life history variables,...Full Text Available
Arbuscular mycorrhizal fungi (AMF) are ecologically important root symbionts of most terrestrial plants. Ecological studies of AMF have concentrated on differences between species; largely assuming...Full Text Available
High speed experimental tests provided data on six parametric cylindrical roller bearings. Four bearing variables were evaluated and the results were correlated with the analytical model developed under Naval Air Propulsion Center Contract N00140-76-C-038...
An approach to the calculation of the quantity of heat consumed in the process of coal formation is presented. The variability of this parameter in a coalification series is analyzed using coals from the Kuznetsk and Tunguska Basins as an example.
The systems for which the algebra of gauge transformations in the lagrangian formalism is closed, are considered. The hamiltonian BRST charge and the BRST-invariant hamiltonian are found explicitly. Their expansions in powers of the ghost variables contain, in general, an infinite number of terms. (orig.).
Glossitis among U.S. military working dogs in South Vietnam was characterized by variable redness and loss of papillae on the anterodorsal third of the tongue; salivation, drooling, and inappetence were the principal clinical signs. Symptomatic treatment ...
The torque-velocity relationship is known to be affected by ageing, decreasing its protective role in the prevention of falls. Interindividual variability in this torque-velocity relationship is partly...Full Text Available
Despite their status as the most speciose group of terrestrial vertebrates, birds exhibit the smallest and least variable genome sizes among tetrapods. It has been suggested that this is because powered...Full Text Available
Exercise is essential for health, yet the amount, duration, and intensity that individuals engage in are strikingly variable, even under prescription. Our focus was to identify the locations and effects...Full Text Available
Microarray data has a high dimension of variables but available datasets usually have only a small number of samples, thereby making the study of such datasets interesting and challenging. In the task...Full Text Available
The aim of the present study focuses on experimentally demonstrating the efficacy of using angularly-variable fiber geometry to achieve the desired tissue-layer selection and probing depths with the further objective of enhancing the sensitivity and specificity of spectral diagnosis in stratified architectures that resemble human cervical epithelia. The morphological and biochemical features of epithelial tissue vary in accordance with tissue depths; consequently, the accuracy of spectroscopic diagnosis of epithelial dysplasia may be enhanced by probing the optical properties of this tissue. When correlated to cellular dysplasia, layer-specific changes in tissue optical properties may be deciphered by reflectance spectroscopy coupled with angularly-variable fiber geometry. This study addresses the utility of using such angularly-variable fiber geometry for resolving spatially-specific spectral signatures of tissue ...
We investigated the effects of wastewater treatment plant (WWTP) discharge on the ecology of bacterial communities in the sediment of a small, low-gradient stream in South Australia. The quantification...Full Text Available
... 1984; Martin-Mora et al., 1995), and parasitism (Rothschild and Rothschild, 1939; Pesigan et al., 1958; Moose, 1963; Pan, ... effects of digeneans are variable; they may enhance (Rothschild and Rothschild...
Understanding the pathogenesis of obesity is now more important than ever, given the remarkable world-wide epidemic. This paper explores the potential role of core temperature in energy balance, and...Full Text Available
Energy confinement in W7-AS has been analyzed in terms of dimensionally exact form free functions employing Bayesian probability theory. The confinement function was set up as a linear combination of dimensionally exact power law terms as already proposed very early by Connor and Taylor. Generation of this expansion basis is dictated by the basic plasma model which one assumes. Based upon data accumulated in W7-AS, which contains the energy content for a wide variety of variable settings, predictions for single variable scans are made. The scaling functions for density and power scans, respectively, are in quantitative agreement with data collected in W7-AS. The result of a single variable scan is therefore already hidden in the data obtained for arbitrary variable choices and can be extracted from the latter by a proper data analysis. Furthermore, the optimal model for the description of the global ...
Detrended fluctuation analysis (DFA) is a recently developed technique suitable for describing scaling behavior of variability in physiological signals. The purpose of this study is to explore...Full Text Available
Certain structural and environmental factors other than technical combination of resources and firm size are hypothesized to affect medical practice output. Four groups of variables related to physician...Full Text Available
BackgroundStudies conducted in developed countries using economic models show that individual- and household- level variables are important determinants of health insurance ownership....Full Text Available
In recent years the modelling of interannual climate variability has been studied, the atmospheric energy and water cycles, and climate simulations with the ECHAM3 model. In addition, the climate simulations of several models have been compared with special emphasis in the area of northern Europe
BackgroundInadequate platelet inhibition despite aspirin and clopidogrel therapy during and after a percutaneous coronary intervention is associated with an impaired clinical outcome....Full Text Available
In this report, the main emphasis is given to (1) the problems associated with the basic calibration of the spectroradiometer and (2) the year-to-year variability of the calibrations of the solar UV network radiometers. Also, the results from intercomparisons of the Brewer and OL 742 spectroradiometers are included
PurposeTo analyze the contributions of cytochrome P4501B1 (CYP1B1) mutations to primary congenital glaucoma (PCG) in Spanish patients.MethodsWe...Full Text Available
An elliptic equation in a rectangle with coefficients depending on a fast variable and with its period being a small parameter is considered. An asymptotic expansion of the solution up to an arbitrary degree of the small parameter is constructed and substantiated by applying the two-scale expansion method.
After discrimination training on a multiple variable-interval extinction schedule of food reinforcement, pigeons were placed on the uncued or mixed version of the same schedule and allowed to make...Full Text Available
Visual assessment of the degree of renal artery stenosis on renal arteriography has a large inter- and intraobserver variability. This degree is usually estimated by the ratio between the most narrowed...Full Text Available
BackgroundMost analyses of spatial clustering of disease have been based on either residence at the time of diagnosis or current residence. An underlying assumption in these analyses...Full Text Available
Antiplatelet resistance has been proposed as a possible mechanism to explain recurrent cardiovascular events in patients who have coronary artery disease and who are undergoing dual antiplatelet therapy....Full Text Available
In the case wherein nonlinear seismic response analyses are carried out, the response values vary due to the variations in materials and modeling. In this paper, nonlinear analyses of several random variables are carried out using: i. a conventional method; ii. a two-point estimation method (i. and ii. are simplified methods); and iii. Monte Carlo simulation (detailed method) to examine the variability of the response in the excessive nonlinear range for seismic responses of shear walls. The analyses are performed to a PWR-3 loop type reactor building which is one of the most typical reactor buildings in Japan. The variations are considered in specified compressive strength of concrete, concrete damping factor, shear wave velocity of soil and shapes of shear stress-strain relation curves of shear walls. As the results by the two simplified methods closely matched the Monte Carlo simulation results, the appropriateness for applying the ...
BackgroundTraditionally in pediatric HIV, the CD4+ T-lymphocyte percent is used in monitoring disease progression due to the variability in absolute CD4+ T-lymphocyte...Full Text Available
The distribution of 20 variable regions resulting from insertion-deletion events in the genomes of the tubercle bacilli has been evaluated in a total of 100 strains of Mycobacterium tuberculosis,...Full Text Available
PurposeTo detail the highly variable ocular phenotypes of a French family affected with an autosomal dominantly inherited vitreoretinopathy and to identify the disease gene.MethodsSixteen...Full Text Available
BackgroundWith the explosion in data generated using microarray technology by different investigators working on similar experiments, it is of interest to combine results across...Full Text Available
Structural variants which cause changes in copy numbers constitute an important component of genomic variability. They account for 0.7% of genomic differences in two individual genomes, of which...Full Text Available
A variable-dispersion electron spectrometer is being installed for use by the Stanford Superconducting Accelerator in conjunction with its Free Electron Laser program. The system has been designed to operate with electron beam energies from 20 MeV to 200 MeV, with a maximum energy resolution of 0.01% FWHM. The maximum energy acceptance is approximately #+-# 5%, as determined by the bending magnet aperture. Resolution is controlled by adjusting the focal conditions at the entrance to a 90 degree bending magnet, while the dispersion is controlled by changing the magnitude and polarity of the field in a quadrupole magnet which immediately follows the bending magnet. 4 refs., 5 figs.
This report describes the design, fabrication, installation and testing of a small variable-speed vertical axis wind turbine (VAWT). This VAWT is unique in its installation using hand tools only; unconventional and simple support system; and variable speed operation under microprocessor control. Initial testing confirmed that the turbine can be controlled by commanded alternator field modulation. Further studies will be directed toward determination of an optimum control algorithm.
Divergence between aircraft engine emission regulations proposed by EPA and ICAO is discussed. Every engine, upon entering service, requires a certificate as to its compliance with emission standards. It is shown that despite the large variability in the measurements, it is possible to devise a certification procedure requiring the testing of one engine only. Statistical modeling of such a test at the 5% significance level is described. Values of the parameter standard deviation/mean recommended as certification standards for various pollutants are given. Features of a rational certification scheme to be formulated are outlined.
We construct representation of the Separated Variables (SoV) for the quantum SL(2,R) Heisenberg closed spin chain and obtain the integral representation for the eigenfunctions of the model. We calculate explicitly the Sklyanin measure defining the scalar product in the SoV representation and demonstrate that the language of Feynman diagrams is extremely useful in establishing various properties of the model. The kernel of the unitary transformation to the SoV representation is described by the same "pyramid diagram" as appeared before in the SoV representation for the SL(2,C) spin magnet. We argue that this kernel is given by the product of the Baxter Q-operators projected onto a special reference state.
For reliable operation and the optimization of production, industrial fermentation processes require appropriate tools for monitoring the process in real time. This work presents the structure and operation of a soft sensor for the on-line monitoring of biomass and product concentration during salinomycin and bacitracin fermentation in an industrial, 80-m^3 batch reactor; moreover it provides a tool for evaluation of batch production verified in industrial application. The process estimation algorithm consists of decoupled growth and product models, which ensures an unbiased convergence of the estimator and the robustness of the model. The production of secondary metabolites is described with a non-structured model upgraded with a variable forgetting factor that demonstrated a successful e...
The idle speed of an internal combustion engine is controlled in response to a variable ignition timing control signal from a microcomputer. The microcomputer derives this control signal as a function of the magnitude of engine speed variation which occurs during engine idle periods to cause the ignition timing to vary quickly in response to a transitory engine load variation. An auxiliary air delivery system may be advantageously incorporated in the idle speed control system to cooperate with the ignition timing control in response to the engine speed variation.
The marine ram-type blowout preventer deployed from an offshore drilling rig has one serious disadvantage, its inaccessibility. A development to promote reliability of the subsea ram-type preventer and reduce the excess running and pulling to charge out rams, is the variable bare ram (VBR). Unlike the standard ram, the VBR has the ability to pack off a range of pipe sizes. Interest in VBR's has been revived and research and development in this equipment goes on at each of three manufacturer's facilities in Houston.
We discuss the inclusive production of D{sup *{+-}} mesons in {gamma}p collisions at DESY HERA, based on a calculation at next-to-leading order in the general-mass variable-flavor-number scheme. In this approach, MS subtraction is applied in such a way that large logarithmic corrections are resummed in universal parton distribution and fragmentation functions and finite mass terms are taken into account. We present detailed numerical results for a comparison with data obtained at HERA and discuss various sources of theoretical uncertainties. (orig.)
We consider the spin-up of the white dwarf in non-magnetic cataclysmic variables (CVs) during secular evolution. If this is unresisted, CVs are quenched as boundary-layer emitters once the binary period has decreased by #approx# 1 hr. Angular momentum loss in nova explosions may, however, prevent the star reaching breakup. If the explosions remove (1 + #epsilon#) x the mass accreted between outbursts, values 0.5 < #approx# #epsilon# < #approx# 1 allow CVs to be modest boundary-layer emitters for most of their lifetimes. Spectral effects will limit their detection as soft X-ray sources. (author).
Energy productivity and energy intensity within the industrial sector of the economy are examined. Results suggest that relative prices and other economic factors can explain much of the variation in both energy productivity and energy intensity for manufacturing and mining and for the industrial sector as a whole. Cyclical factors, seasonal factors and trend variables are also useful in explaining variation in these data, both for annual and monthly time series. Of the variables examined, it appears that the relative price of energy is a highly significant factor in accounting for the difference between actual industrial energy intensity and that which might have been expected had pre-1973 trends continued.
The effects of variable hardness, pH, alkalinity, humics, and suspended clay on the chemical speciation of copper and its toxicity to fathead minnow larvae in Lake Superior water were investigated. Two proposed methods (toxicity factors and chemical speciation) for predicting LC50 values in specific natural waters from laboratory toxicity data and the average site specific values of general water quality parameters were evaluated. The accuracy of the cupric ion-selective electrode in determining CU/sup +2/ activities in ambient and chemically altered Lake Superior water was also determined.
We present a protocol for quantum key distribution using discrete modulation of coherent states of light. Information is encoded in the variable phase of coherent states which can be chosen from a regular discrete set ranging from binary to continuous modulation similar to phase-shift keying in classical communication. Information is decoded by simultaneous homodyne measurement of both quadratures and requires no active choice of basis. The protocol utilizes either direct or reverse reconciliation both with and without postselection. We analyze the security of the protocol and show how to enhance it by the optimal choice of all variable parameters of the quantum signal.
In this project we determined primary production and optical variability in the shelf and slope waters off of Cape Hatteras, N.C. These processes were addressed in conjunction with other Ocean Margins Program investigators, during the Spring Transition period and during Summer. We found that there were significant differences in measured parameters between Spring and Summer, enabling us to develop seasonally specific carbon production and ecosystem models as well as seasonal and regional algorithm improvements for use in remote sensing applications.
A fermionic - based on Grassmann--Berezin calculus of anticommuting variables - topological quantum field theory (TQFT) is considered, mainly in three dimensions. It is defined for piecewise-linear manifolds and, for a given triangulation, deals only with a finite number of variables. Despite its simple nature, it can distiguish between lens spaces L(7,1) and L(7,2). And despite its origin from a kind of Reidemeister torsion, it does this without using nontrivial representations of the fundamental group. Also, symbolic calculations are presented giving strong evidence of existence of similar theory in four dimensions.
Pippenger (2011) recently proposed a solution to the longstanding forward-bias puzzle. He argues that the puzzling estimates obtained using the standard equation for the efficient markets hypothesis are due to omitted variable bias. He identifies the missing variables as the future change in the forward exchange rate and the future interest differential. When these are added to the standard equation, he finds a one-to-one relationship between the future change in the spot rate and the forward premium. However, we argue that his equation can only test covered interest parity and offers no insight into the forward-bias puzzle.
A reliability approach for probabilistic modeling of one-dimensional non-reactive and reactive transport in porous media provides two important quantitative results: (1) an estimate of the probability that dimensionless concentration equals or exceeds some specified level and, (2) the sensitivity of the probabilistic outcome to likely changes in each uncertain variable. The reliability approach is particularly attractive because it can incorporate various marginal probability density functions (PDF) for any of the uncertain variables. In this work uncertain variables include: groundwater flow velocity, diffusion coefficient, dispersivity, distribution coefficient, porosity and bulk density. The primary objective is to examine how the probabilistic outcome is influenced by choice of marginal PDF, correlation and magnitude of uncertainty for the variables. Because little information exists concerning the ...
We study the high-energy emission of the Galactic black hole candidate GX 339-4 using INTEGRAL/SPI and simultaneous RXTE/PCA data. By the end of January 2007, when it reached its peak luminosity in hard X-rays, the source was in a bright hard state. The SPI data from this period show a good signal to noise ratio, allowing a detailed study of the spectral energy distribution up to several hundred keV. As a main result, we report on the detection of a variable hard spectral feature (>150 keV) which represents a significant excess with respect to the cutoff power law shape of the spectrum. The SPI data suggest that the intensity of this feature is positively correlated with the 25 - 50 keV luminosity of the source and the associated variability time scale is shorter than 7 hours. The simultaneous PCA data, however, show no significant change in the spectral shape, indicating that the source is not undergoing a canonical state transition. We ...
In May 1985, a National Pollutant Discharge Elimination System permit was issued for the Oak Ridge Y-12 Plant, a nuclear weapons components production facility located in Oak Ridge, Tennessee, and operated by Martin Marietta Energy Systems, Inc., for the US Department of Energy. As a condition of the permit, a Biological Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Oak Ridge Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek), in particular, the growth and propagation of fish and aquatic life, as designated by the Tennessee Department of Health and Environment. A second purpose for the BMAP is to document the ecological effects resulting from implementation of a water pollution control program that will include construction of nine new wastewater treatment facilities over the next 4 years. Because of the complex nature of the effluent discharged to East Fork Poplar Creek and ...
We present 14 years of contemporaneous photometric and spectroscopic observations of 28 solar analog stars, taken with the Tennessee State University Automatic Photometric Telescopes at Fairborn Observatory and the Solar-Stellar Spectrograph at Lowell Observatory. These are the best observed and most nearly Sun-like of the targets in our magnitude-limited (V #<=# 7.5) sample. The correlations between luminosity and activity reveal the expected inverse activity-brightness correlations for active stars. Strong direct correlations between activity and brightness are not prevalent for the less active solar age stars, but are precision limited. The Sun does not appear to have unusually low photometric variability when compared with the most Sun-like inactive solar analogs. We present evidence that the activity index R'_H_K is not a good discriminant of Maunder Minimum candidate stars. On the basis of a star that appears to have transitioned from a ...
Identifying stable isotope variation and mineralogical changes in fractured rock may help establish the history of climatic and geomorphological processes that might affect the isolation properties of a waste repository site. This study examines the use of the stable isotope ratios of oxygen ({sup 18}O/{sup 16}O) and carbon ({sup 13}C/{sup 12}C) in authigenic minerals as hydrogeochemical tools tracing low-temperature rock-water interaction in variably-saturated fractured stuff. Isotopic compositions of fracture-filling and rock matrix minerals in the Apache Leap tuff, near Superior, Arizona were concordant with geothermal temperatures and in equilibrium with water isotopically similar to present-day meteoric water and groundwater. Oxygen and carbon isotope ratios of fracture-filling, in unsaturated fractured tuff, displayed an isotopic gradient believed to result from near-surface isotopic enrichment due to evaporation rather than the effects of rock-water ...
The present investigation was conducted at Ismaillia Research Station-Agricultural Research Center, Ismaillia Governorate, during the two successive seasons of 2000 and 2001. Two varieties of peanut (Arachis hypogaea L) namely Giza 4 and Giza 5 were treated with gamma ray doses; 10,15, 20, 25 Kr in order to induce genetic variability and to study the importance of the relative contribution of peanut yield components by employing some statistical procedures, i.e. simple correlation, multiple linear regression and stepwise regression analysis. The results showed that, there was significant positive correlation between seed yield/plant and no. of pods/plant, 100 seed weight, shelling percentage and pod yield/plant, and there was significant positive correlation between pod yield/plant and no of seed/plant,100 pod weight and 100 seed weight. The multiple linear regression analysis clearly showed that the relative contribution (R"2%) of the yield components, no. of ...
Starting from the original collective Hamiltonian of Bohr and separating the beta and gamma variables as in the X(5) model of Iachello, an exactly soluble model corresponding to a harmonic oscillator potential in the beta-variable (to be called X(5)-$\\beta^2$) is constructed. Furthermore, it is proved that the potentials of the form $\\beta^{2n}$ (with n being integer) provide a ``bridge'' between this new X(5)-$\\beta^2$ model (occuring for n=1) and the X(5) model (corresponding to an infinite well potential in the beta-variable, materialized for n going to infinity. Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are given for the potentials $\\beta^2$, $\\beta^4$, $\\beta^6$, $\\beta^8$, corresponding to E(4)/E(2) ratios of 2.646, 2.769, 2.824, and 2.852 respectively, compared to the E(4)/E(2) ratios of 2.000 for U(5) and 2.904 for X(5). Hints about nuclei showing this ...
The far infrared free electron laser (FEL) has been being developed since 1990 using the L-band electron linac at the Institute of Scientific and Industrial Research, Osaka University. The first lasing was obtained in 1994 at wavelengths from 32 to 40 #mu#m. The FEL is now being modified suitable for user experiments. The wiggler with a fixed magnet gap used in the original FEL has been remodeled to make the magnet gap variable. In order to optimize the variable range of the gap, the gain and the diffraction loss were calculated. The peak gain is calculated to be 270% and the diffraction loss to be 22% at 150 #mu#m. The wavelength is expected to be variable from 25 up to at least 150 #mu#m. The two bending magnets in the optical resonator have been remodeled and the vacuum chambers with larger vertical sizes for them have been newly made so that the diffraction loss in these parts becomes smaller than that in the vacuum ...
The purpose of this study was to examine the relationship between histomorphometric variables of cancellous bone structure and ultimate compressive strength (UCS) in the second lumbar vertebra (L2) and to determine whether structural variables in the iliac crest are predictive of the same variables and of UCS in L2. At autopsy, 7.5 mm diameter cores were removed from the iliac crest and from L2 of 29 subjects who had died suddenly without bone disease. Cancellous bone volume (BV/TV, %) was significantly lower in L2 than in iliac crest due to lower trabecular number (Tb.N, per mm) and thickness (Tb.Th, microns). There were significant correlations between iliac crest and L2 for BV/TV, Tb.N and trabecular separation (Tb.Sp, microns), but not for Tb.Th. BV/TV was negatively correlated, and Tb.Sp was positively correlated with age at both sites. Tb.Th was not significantly correlated with age in the iliac crest, but a ...
We present an optimal control approach for the solidification process of a melt in a container. The process is described by a two phase Stefan problem with the free boundary (interface between the two phases) modelled as a graph. We control the evolution of the free boundary using the temperature on the container wall. The control goal consists in tracking a prescribed evolution of the free boundary. We achieve this goal by minimizing a appropriate cost functional. The resulting minimization problem is solved numerically by a steepest descent method with step size control, where the gradient of the cost functional is expressed in terms of the adjoint variables. Several numerical examples are presented which illustrate the performance of the method. The novelty of the approach presented consists in using a sharp interface model for the control of the free boundary. This guarantees direct access to the free boundary as optimization variable in ...
This study examines the sensitivity of the travel time distribution predicted by a reference case model to (1) scale of representation of the model parameters, (2) size of the model domain, (3) correlation range of log-transmissivity, and (4) cross correlations between transmissivity and effective thickness. The basis for the reference model is the preliminary stochastic travel time model previously documented by the Basalt Waste Isolation Project. Results of this study show the following. The variability of the predicted travel times can be adequately represented when the ratio between the size of the zones used to represent the model parameters and the log-transmissivity correlation range is less than about one-fifth. The size of the model domain and the types of boundary conditions can have a strong impact on the distribution of travel times. Longer log-transmissivity correlation ranges cause larger variability in the predicted travel times. ...
These summary descriptive data of ethnically similar cohorts of indigenous and migrant Japanese males have shown similarities or slight differences in characteristics wholly or largely genetically determined, such as blood groups, stature, and skeletal size. Differences have been noted in characteristics largely environmental or behavioral, such as diet and cigarette smoking habit, as well as in characteristics determined by a varying mixture of genetic and environmental influences, such as weight, blood pressure, glucose tolerance, and serum lipid and uric acid levels. Detailed analyses of the distributions of laboratory variables, of dietary data obtained by different methods, and of correlations among laboratory, dietary, physical, and demographic variables are currently in progress. Also part of the study plan are determinations of disease prevalence from evaluation of examination, laboratory, and electrocardiographic findings, of disease ...
Automated, variable volume unloaders provide the ability to smoothly load/unload reciprocating compressors to maintain ideal operations in ever-changing environments. Potential advantages provided by this load control system include: maximizing unit capacity, optimizing power economy, maintaining low exhaust emissions, and maintaining process suction and discharge pressures. Obstacles foreseen include: reliability, stability, serviceability and automation integration. Results desired include: increased productivity for the compressor and its operators, increased up time, and more stable process control. This presentation covers: system design features with descriptions of how different types of the devices were developed, initial test data, and how they can be effectively operated; three actual-case studies detailing the reasons why automated, hydraulically controlled, variable volume, head-end unloaders were chosen over other types of ...
The aim of this paper is to present and evaluate control strategies for adjustment and preservation of air quality, thermal and visual comfort for buildings' occupants while, simultaneously, energy consumption reduction is achieved. Fuzzy PID, fuzzy PD and adaptive fuzzy PD control methods are applied. The inputs to any controller are: the PMV index affecting thermal comfort, the CO{sub 2} concentration affecting indoor air quality and the illuminance level affecting visual comfort. The adaptive fuzzy PD controller adapts the inputs and outputs scaling factors and is based on a second order reference model. More specifically, the scaling factors are modified according to a sigmoid type function, in such a way that the measured variable to be as closer as possible to the reference model. The adaptive fuzzy PD controller is compared to a non-adaptive fuzzy PD and to an ON-OFF one. The comparison criteria are the energy required and the controlled ...
It is currently unclear if the potential for West Nile virus transmission by mosquito vectors in the eastern United States is related to landscape or climate factors or both. We compared abundance of vector species between urban and suburban neighborhoods of Henrico County, VA, in relation to the following factors: temperature, precipitation, canopy cover, building footprint, and proximity to drainage infrastructure. Mosquitoes were collected throughout the 2005, 2006, and 2007 seasons and tested for West Nile virus (WNV) in pools of 10-50. Test results of mosquito pools were compared to average site abundance from 37 sites in Henrico County, VA; abundance was then examined in relation to ecological variables. Urban infrastructure was positively correlated with the abundance of Culex pipiens L./Cx. restuans, and our findings implicate combined sewer overflow systems as large contributors to Culex vector populations. No measure of urbanization examined in our study ...
AGILE pointed observations performed from July 9, 2007 to October 30, 2009 are a recent, high quality gamma-ray data archive for monitoring studies of medium to high brightness gamma-ray sources in the 30 MeV -50 GeV energy range. We present a variability study of the 1AGL sources over the complete AGILE pointed Observation Blocks (OBs) dataset. The first AGILE Gamma-Ray Imaging Detector (GRID) catalog (Pittori et al. 2009) included a significance-limited (4 sigma) sample of 47 sources (1AGL), detected with a conservative analysis over a first-year non-uniform sky coverage dataset. In this analysis we used data of an improved full Field of View (FOV) event filter, on a much larger (about 27.5 months) observation dataset, analyzing each OB separatedly. This data processing resulted in an improved source list as compared to the 1AGL one. We present here some results on the variability of some of these sources.
The Environmental Kuznets Curve (EKC) hypothesis states that pollution levels increase as a country develops, but begin to decrease as rising incomes pass beyond a turning point. In EKC analyses, the relationship between environmental degradation and income is usually expressed as a quadratic function with the turning point occurring at a maximum pollution level. Other explanatory variables have been included in these models, but income regularly has had the most significant effect on indicators of environmental quality. One variable consistently omitted in these relationships is the price of energy. This paper analyzes previous models to illustrate the importance of prices in these models and then includes prices in an econometric EKC framework testing energy/income and CO{sub 2}/income relationships. These long-run price/income models find that income is no longer the most relevant indicator of environmental quality or energy demand. Indeed, ...
The Environmental Kuznets Curve (EKC) hypothesis states that pollution levels increase as a country develops, but begin to decrease as rising incomes pass beyond a turning point. In EKC analyses, the relationship between environmental degradation and income is usually expressed as a quadratic function with the turning point occurring at a maximum pollution level. Other explanatory variables have been included in these models, but income regularly has had the most significant effect on indicators of environmental quality. One variable consistently omitted in these relationships is the price of energy. This paper analyzes previous models to illustrate the importance of prices in these models and then includes prices in an econometric EKC framework testing energy/income and CO_2/income relationships. These long-run price/income models find that income is no longer the most relevant indicator of environmental quality or energy demand. Indeed, we ...
This report describes the LIFECC computer program developed for the purpose of calculating the cost of energy produced by wind systems according to the principles of life cycle costing (LCC). Following a brief explanation of the LCC concept and its advantages, input variables to the program and their importance to various program users, including manufacturers and designers, utilities, various institutions and consumers, are explained. A detailed user's guide to the program is then provided, together with a sensitivity analysis which discusses the impact of key variables on wind system cost of energy and the importance of cash flow to the wind system purchaser. Sample cases of program output and an LIFECC program listing are provided.
As is well documented, subprime mortgage markets carried significant default risk. This paper investigates the relationship between default risk premium, stock market conditions and macroeconomic variables during the financial crisis. Using iTraxx Japan Credit Default Swap (CDS) index spreads covering the period from March 2006 to November 2009, we employ a time-varying dynamic factor model with Markov regime switching to generate regime probabilities for default risk. We analyze the sensitivity of default risk premium changes to stock market conditions and macroeconomic variables by using two-state Markov switching models: a crisis regime sparked by rising loan defaults in the sub-prime mortgage market, and a non-crisis regime. We found strong evidence that the relationship between defaul...
This paper presents a semi-active vibration control of a scaled two-span bridge structure. Magneto-rheological fluid dampers are utilized as the semi-active energy absorbing deices and a bridge vibration control system is developed. Closed-loop control system based on fuzzy logic is used to suppress the bridge deck motion under random excitations. The sufficient condition for the closed-loop stability of the fuzzy control system is derived from the variable structure system theory. It is demonstrated that this stable fuzzy control system can significantly reduce the relative deck displacement using about 55 percent less power compared to passive-on state, while the absolute deck acceleration is relatively unaffected.
The broad use of Six Sigma in the improvement of all types of processes has provided new insight for how to design, analyze, and interpret formulation studies and mixture experiments. Experience has shown that, consistent with the Pareto principle, there are typically three to six key variables that have major effects on the performance of the process. Identifying these key variables increases your ability to control and optimize the process. Applying this concept to formulation studies suggests that we should be searching for those critical few components that are driving the performance of the product formulation. This thinking changes how we approach both the design and analysis phases of product formulation studies, including the reassessment of formulations in use today. A review of t...
Our investigation concerns the class of Josephson-like systems, sharing the same nonlinear Hamiltonian. Among the latter a Josephson junction with an external biasing circuit is considered. We diagonalize the fully nonlinear Hamiltonian (in the superconductive regime of the junction) in the Fock space of the TBHA (two-boson Heisenberg algebra) and prove that such algebra leads quite naturally to the theoretical realization of codewords and logical operators: the codewords are defined as the even and odd coherent states of the TBHA, while the logical operators are expressed in terms of operators in the same algebra. Our theoretical construction corresponds to a continuous variable quantum computation scheme; the continuous variables are identified in terms of the physical operators of the junction. The link between this scheme and the technique of fermionization of bosonic systems is also discussed.
This research will be helpful for people to display the 2-dimensiona projective models of 4-variable actual problems in many fields, in order to investigate deeply those actual problems. By using the theory of N-dimensional finite rotation group of the regular polytopes, the author established the 2-dimensional projective model of 4-dimensional rectangular coordinate system, and deduced a transformation matrix, and adopt it to display successfully the 2-dimensional overall shapes of two most complicated regular polytopes 120-Cell and 600-Cell. In the meantime, the author calculated all the vertex coordinates and determine the joint relationships between adjacent vertices of the regular polytopes 120-Cell and 600-Cell. Also, this provided a pattern for displaying the 2-dimensional projective model of 4-variable actual problem.
Although incompressible fluid flows can be regarded as a particular case of a general problem, numerical methods and the mathematical formulation aimed to solve compressible and incompressible flows have their own peculiarities, in such a way, that it is generally not possible to attain both regimes with a single approach. In this work, we start from a typically compressible formulation, slightly modified to make use of pressure variables and, through augmenting the stabilising parameters, we end up with a simplified model which is able to deal with a wide range of flow regimes, from supersonic to low speed gas flows. The resulting methodology is flexible enough to allow for the simulation of liquid flows as well. Examples using conservative and pressure variables are shown and the results are compared to those published in the literature, in order to validate the method. (author)
Early technical history of electric supply to electric railways is briefly reviewed as an introduction to the following seven papers included in this special issue on technologies for saving energy in railway operation. Continuous power supply played a significant role in the early history of railway technologies. The variable voltage variable frequency (VVVF) power electronic technology had also a substantial impact on railway traction systems after 1980s. VVVF technology made it possible to have more efficient drives, downsize rolling stocks, and develop regenerative brakes. Because detailed discussions on each technical development are presented in the following papers, the general remarks of those technologies made in this introduction provide logical links to the ideas presented in th...
Viddi, F. A., Hucke-Gaete, R., Torres-Florez, J. P., and Ribeiro, S. 2010. Spatial and seasonal variability in cetacean distribution in the fjords of northern Patagonia, Chile. - ICES Journal of Marine Science, 67: 959-970. Compared with other Chilean coastal areas, little is known about the diversity and distribution of cetaceans in northern Patagonian fjords. Between December 2000 and November 2001, surveys on platforms of opportunity were undertaken in southern Chile to evaluate species richness and the spatial and seasonal distribution of cetaceans. Nine species were recorded, blue, humpback, and minke whales, Peales dolphin, Chilean dolphin, killer whale, false killer whale, bottlenose dolphin, and Cuviers beaked whale. The pattern of cetacean distribution displayed significant season...
The literature regarding the free vibration analysis of Bernoulli?Euler and Timoshenko beams under various supporting conditions is plenty, but the free vibration analysis of Reddy?Bickford beams with variable cross-section on elastic soil with/without axial force effect using the Differential Transform Method (DTM) has not been investigated by any of the studies in open literature so far. In this study, the free vibration analysis of axially loaded and semi-rigid connected Reddy?Bickford beam with variable cross-section on elastic soil is carried out by using DTM. The model has six degrees of freedom at the two ends, one transverse displacement and two rotations, and the end forces are a shear force and two end moments in this study. The governing differential equations of motion of the r...
Possible factors regulating phytoplankton variability in the Arabian (Persian) Gulf were analyzed on the basis of satellite observations and meteorological data (1997-2009), including remotely-sensed chlorophyll a concentration (CHL), sea surface temperature, wind, solar radiation, precipitation, and aerosols. Shallow waters of northwestern Gulf influenced by Shatt Al-Arab River discharge were more productive than open Gulf waters, although seasonal CHL patterns in this and other shallow regions looked unrealistic likely because the CHL signal was obscured by bottom reflection. Therefore our further analyses focused on the open Gulf waters, which show a subtropical seasonal CHL cycle with maximum in winter and minimum in spring-summer. This cycle, however, was decoupled from the seasonal e...
It is not clear whether males in all mammalian species adjust their copulatory behavior when faced with risk of sperm competition (RSC). Previous work on meadow voles, Microtus pennsylvanicus, indicated that males increase their sperm expenditure but not the number of ejaculations in the presence of odors of a conspecific male. The present study follows up on this work and asks whether male meadow voles modify any aspect of their copulatory behavior when they face a RSC. We examined 46 variables of copulatory behavior and found that the presence of odors from a conspecific male did not affect any of these variables. Thus, male meadow voles, unlike some other species of mammals, do not adjust their copulatory behavior when exposed to cues associated with an elevated RSC.
Many of the world's coral reefs suffered high coral mortality during the 1998 ENSO, with the highest mortality in the western Indian Ocean (WIO). A meta-analysis of field data on change in coral cover across the 1998 ENSO event was conducted for 36 major reef areas in the WIO, and relationship of the change with the historical sea-surface temperature (SST) variability investigated. WIO reefs were categorized into three major SST groups of differing coral cover change. Cover change was negatively associated with standard deviation (SD) SST until about SD 2.3, with increasing flatness of the SST frequency distributions. It increased with further increase in SD as the SST distributions became strongly bimodal in the Arabian/Persian Gulf area. The study indicates that environmental resistance/...
In a fluoroscopic imaging system, image quality and patient dose are both affected by the optical system linking the image intensifier with the video camera. The effect on patient exposure of increasing the optical iris aperture size over that required for other procedures performed on the same imaging system was investigated for the air-contrast barium enema examination. Using a large-area transmission ionisation chamber to monitor the Roentgen-area-product of entrance exposure, a decrease in fluoroscopic radiation of greater than 50% was clinically documented for a fluoroscopic system utilising kVp and mA variable automatic brightness control. For this iris change, the video image was of acceptable quality for positioning and monitoring the patient, and no deleterious effect was detected in the conduct of the air-contrast exam. The availability of a variable-sized operator-selectable iris diaphragm would permit this dose-reduction approach to ...
Abstract In this first systematic attempt to characterize the intranight optical variability (INOV) of TeV-detected blazars, we have monitored a well-defined set of nine TeV blazars on total 26 nights during 2004-10. In this R- or V-band-monitoring programme only one blazar was monitored per night and the minimum duration was close to 4-h, the average being 5.3 h per night. Using the CCD for strictly simultaneous photometry of the blazar and nearby reference stars (N-star photometry), an INOV detection threshold of -1-2-per cent was achieved in the densely sampled differential light curves derived from our data. We have further expanded the sample by including another 13 TeV blazars, taking advantage of the availability in the literature of INOV data, including those published earlier in o...
Native to Southeast Asia, Hygrophila polysperma is an invasive aquatic weed of lotic habitats in the southern United States and Mexico. An increase in the number of water bodies invaded by hygrophila since 1990 suggests that current methods employed to control this weed are inadequate. Classical biological control may be a viable option for long term regulation of hygrophila in the invaded range. In this study, we used the Maximum Entropy Species Distribution Model (MaxEnt) to prioritize climatically suitable native habitats in India and Bangladesh for conducting exploratory surveys to collect biological control agents. In total, 164 point occurrences from the United States and Mexico and 20 predictor variables, including 19 bioclimatic variables and altitude, were used to predict the nati...
A dense Pd-Ag membrane reactor (MR) with 100% hydrogen selectivity packed with either Rh/La2O3 or Rh/La2O3-SiO2 as catalysts was used to carry out the dry reforming of methane. The membrane reactor simulation was performed using a well-known reactor model. For this purpose, we employed the equations derived from complete kinetic studies of the dry reforming of methane reaction in connection with both catalysts. In addition, we developed the kinetic equation for the reverse water gas shift reaction (RWGS). The combination of detailed kinetic studies with the measured permeation flux for the Pd-Ag membrane allowed a complete comparison between experimental and simulated operation variables. The variables studied for both catalysts were methane conversion and hydrogen permeation as a function...
One of the most common types of functions in mathematics, physics, and engineering is a sum of products, sometimes called a partition function. After "normalization," a sum of products has a natural graphical representation, called a normal factor graph (NFG), in which vertices represent factors, edges represent internal variables, and half-edges represent the external variables of the partition function. In physics, so-called trace diagrams share similar features. We believe that the conceptual framework of representing sums of products as partition functions of NFGs is an important and intuitive paradigm that, surprisingly, does not seem to have been introduced explicitly in the previous factor graph literature. Of particular interest are NFG modifications that leave the partition function invariant. A simple subclass of such NFG modifications offers a unifying view of the Fourier transform, tree-based reparameterization, loop calculus, and ...
The disrupted magnetic braking theory for the period gap of cataclysmic variable systems is used to study the binary evolution of low-mass main-sequence-like stars with white dwarf companions. The model is able to reproduce the observed location and width of the gap provided that the average mass transfer rates above the upper edge of the gap are greater than about 1.9 x 10 to the -9th solar masses/yr. For the case of angular momentum loss by magnetic braking, the slope of the mass transfer rate with respect to orbital period is shown to range from 3.4 to 3.7. For the evolutionary sequences considered, the He-3 abundance at the surface of the secondary exceeds 0.0015 after the complete mixing phase, resulting in modifications in the nuclear burning development of nova explosions. 31 refs.
Because the state of a free-floating space robot model is uncertain and sudden changes in the model parameters might undermine the stability of the system, this paper proposes a control strategy based on a variable structure neural integrated controller. This scheme does not need a precise space robot model, making use of the radial basis function neural network ability approach to learn about an uncertain model. The network weights are adjusted online in real-time. During the early period of the control phase and parameter changes, the variable structure controller compensates for the uncertain model which the neural network could not learn well. It also creates global asymptotic stability for the whole closed-loop system. Simulation results show that the controller can handle bad changea...
Variability in production is one of the largest factors that negatively impacts construction project performance. A common construction practice to protect production systems from variability is the use of buffers (Bf). Construction practitioners and researchers have proposed buffering approaches for different production situations, but these approaches have faced practical limitations in their application. A multiobjective analytic model (MAM) is proposed to develop a graphical solution for the design of Work-In-Process (WIP) Bf in order to overcome these practical limitations to Bf application, being demonstrated through the scheduling of repetitive building projects. Multiobjective analytic modeling is based on Simulation?Optimization (SO) modeling and Pareto Fronts concepts. Simulation...
Summary Many important moral decisions, particularly at the policy level, require the evaluation of choices involving outcomes of variable magnitude and probability. Many economic decisions involve the same problem. It is not known whether and to what extent these structurally isomorphic decisions rely on common neural mechanisms. Subjects undergoing fMRI evaluated the moral acceptability of sacrificing a single life to save a larger group of variable size and probability of dying without action. Paralleling research on economic decision making, the ventromedial prefrontal cortex and ventral striatum were specifically sensitive to the "expected moral value" of actions, i.e., the expected number of lives lost/saved. Likewise, the right anterior insula was specifically sensitive to outcome p...
Estimates of climate change impacts are plague with uncertainties from many physical, biological, and social-economic processes. Among the urgent research priorities, more comprehensive assessments of impacts that better represent the uncertainties are needed. Here, we develop a new super-ensemble-based probabilistic projection approach to account for the uncertainties from CO2 emission scenarios, climate change scenarios, and biophysical processes in impact assessment model. We demonstrate the approach in addressing the probabilistic changes of maize production in the North China Plain in future. The new process-based general crop model, MCWLA [Tao, F., Yokozawa, M. Zhang, Z., 2009. Modelling the impacts of weather and climate variability on crop productivity over a large area: a new proc...
In undirected graphical models, learning the graph structure and learning the functions that relate the predictive variables (features) to the responses given the structure are two topics that have been widely investigated in machine learning and statistics. Learning graphical models in two stages will have problems because graph structure may change after considering the features. The main contribution of this paper is the proposed method that learns the graph structure and functions on the graph at the same time. General graphical models with binary outcomes conditioned on predictive variables are proved to be equivalent to multivariate Bernoulli model. The reparameterization of the potential functions in graphical model by conditional log odds ratios in multivariate Bernoulli model offers advantage in the representation of the conditional independence structure in the model. Additionally, we impose a structure penalty on groups of ...
Short-duration measurements have been widely used to screen for exposures to elevated radon concentrations in individual houses or at state or regional levels. However, a number of factors, including spatial and temporal variability in radon concentrations, must be considered before comparison to concentration guidelines can be made. Daily variations in radon concentration can lead to inherent measurement uncertainties ranging from 20 to 100+ percent. Differences in radon concentration due to seasonal effects and/or sampling location are also variable, and do not appear to be regionally consistent. Winter/summer concentration ratios, for example, have been observed to vary by as much as a factor of 10 in basements and by a factor of 5 in first floors. In this paper the implications of these uncertainties on the use of short-term sampling for inferring long-term exposures are discussed.
A variable-compression ratio, direct-injection diesel engine (VCR) has been designed and assembled at Southwest Research Institute with the intention of examining the current procedures for rating the ignition quality of diesel fuels and the meaning of ignition delay as an indicator of ignition and combustion quality. Using a slightly modified ASTM D 613 procedure, the engine has been used to rate the ignition quality of 43 different test fuels. The ratings obtained in the VCR engine are compared to the corresponding rating obtained using the standard cetane rating procedure. Some of the problems associated with the standard procedure became apparent during these experiments. The experimental results are discussed in terms of the problems and the advantages of a proposed VCR-based rating procedure.
Abstract The Eiffel Tower edifice is situated in the Lucky Strike hydrothermal vent field at a mean depth of 1690-m on the Mid-Atlantic Ridge (MAR). At this 11-m-high hydrothermal structure, different faunal assemblages, varying in visibly dominant species (mussels and shrimp), in mussel size and in density of mussel coverage, were sampled biologically and chemically. Temperature and sulphide (-S) were measured on the different types of mussel-based assemblages and on a shrimp-dominated assemblage. Temperature was used as a proxy for calculating total concentrations of CH4. Based on the physico-chemical measurements, two microhabitats were identified, corresponding to (i) a more variable habitat featuring the greatest fluctuations in environmental variables and (ii) a second, more stable, ...
The problem of electrical parameters identification in complex systems, and in particular in electric railway traction systems, is considered. Parameters are determined by an indirect approach: only the terminal variables (voltages and currents and, impedance and admittance, which can be readily calculated) are measured and the per-unit-length electrical parameters are determined using a multiconductor transmission line model of the track section under test. It will be shown that some parameters cannot be measured directly, that they are not constant with frequency and that they may depend on other external conditions. An indirect method for parameters identification is proposed through an adaptive algorithm (AA), so that the calculated terminal variables match the measured ones. The AA is...
In this study, usage of a variable speed refrigeration system in latent heat thermal energy storage (LHTES) system is investigated to increase energy storage efficiency. Four different compressor speed control cases are compared to obtain a constant heat transfer fluid (HTF) temperature at the inlet of the energy storage tank. These control cases are (i) control with evaporation temperature, (ii) control with ethylene glycol temperature at the outlet section of evaporator, (iii) control with suction pressure of the compressor and (iv) on/off control. By means of the experimental analysis the best control strategy is obtained as control with Case (ii), in terms of stability of inlet temperature of heat transfer fluid, variations of energy efficiency of LHTES and coefficient of performance (...
In this study, ethanol organosolv pretreatment was investigated and optimized for the pretreatment of empty palm fruit bunch using (1) response surface methodology based on three-variable central composite design and (2) the combined severity parameters. The reaction parameters studied were sulfuric acid concentration (0.5-2.0%), reaction temperature (160-200^oC) and residence time (45-90min). Both models provide valuable and complementary informations: using combined severity parameters, very good predictions were obtained concerning xylan and lignin extraction whereas central composite design is the best model for glucose production. The optimal values of the variables were as the followings: sulfuric acid 2.0% w/w, 160^oC, 78min and the experimental values (96.0%) concerning glucose and...
The objective of this study is to analyze the effects of heat loss characterized by a percentage of the fuel's energy, friction and variable specific heats of working fluid on the performance of an air standard Otto cycle with a restriction of maximum cycle temperature. A more realistic and precise relationship between the fuel's chemical energy and the heat leakage that is based on a pair of inequalities is derived through the resulting temperature. The variations in power output and thermal efficiency with compression ratio, and the relations between the power output and the thermal efficiency of the cycle are presented. The results show that the power output as well as the efficiency where maximum power output occurs will increase with increase of the maximum cycle temperature. The temp...
An adaptive contingency selection process is set up which produces outage lists in order to guarantee on-line network security control. The quality index system used so far did not detect and reveal all critical variables due to observation problems in the mapping of two functions. The new process uses the results of the outage simulation computing of the system status just past for the drawing up of an up-to-date outage list. A linear correcting function transform the G{sub 2}-values of the standard quality index method - which still incorporate the observation problem effect - into improved values G. Studies which use data from realstic high-voltage networks prove that the detection of critical variables is far superior to ordinary methods. (orig.).
In this paper we examine the relationship between covariance and unitarity for quantum gravity in Ashtekar variables. A usual description would discard half of the original Lorentz group, in exchange for the resulting simplifications of general relativity. We start by quantizing a trivial SL(2,C) gauge theory resulting in a nonunitary covariant theory. By the addition of a total time derivative we transform this into a unitary theory of the Ashtekar description of gravity with complete accountability of the degrees of freedom. We find that covariance on the spacetime level bears a direct relationship to covariance on the level ofthe quantum fields themselves. This procedure can in principle be applied to any totally constrained system, and bears a resemblance to the Gupta--Bleuler method. Finally, we make some observation regarding the loop representation of the SL(2,C) connection.
One of the goals of the DARPA Virtual Soldier Project is to aid the field medic in the triage of a casualty. In Phase I, we are currently collecting 12 baseline experimental physiological variables and a cardiac gated Computed Tomography (CT) imagery for use in an prototyping a futuristic electronic medical record, the "Holomer". We are using physiological models and Kalman filtering to aid in diagnosis and predict outcomes in relation to cardiac injury. The physiological modeling introduces another few hundred variables. Reducing the complexity of the above into easy-to-read text to aid in the triage by the field medic is the challenge with multiple display solutions. A description of the possible techniques follows. PMID:15718701
A multivariate bioprocess control approach, capable of tracking a pre-set process trajectory correlated to the biomass or product concentration in the bioprocess is described. The trajectory was either a latent variable derived from multivariate statistical process monitoring (MSPC) based on partial least squares (PLS) modeling, or the absolute value of the process variable. In the control algorithm the substrate feed pump rate was calculated from on-line analyzer data. The only parameters needed were the substrate feed concentration and the substrate yield of the growth-limiting substrate. On-line near-infrared spectroscopy data were used to demonstrate the performance of the control algorithm on an Escherichia coli fed-batch cultivation for tryptophan production. The controller showed good ability to track a defined biomass trajectory during varying process dynamics. The robustness of the control was high, despite significant external ...
Biodynamic parameters of the ragworm Nereis diversicolor from southern Spain and south England were experimentally derived to assess the inter-population variability of physiological parameters of the bioaccumulation of Ag, Cd and Zn from water and sediment. Although there were some limited variations, these were not consistent with the local metal bioavailability nor with temperature changes. Incorporating the biodynamic parameters into a defined biodynamic model, confirmed that sediment is the predominant source of Cd and Zn accumulated by the worms, accounting in each case for 99% of the overall accumulated metals, whereas the contribution of dissolved Ag to the total accumulated by the worm increased from about 27 to about 53% with increasing dissolved Ag concentration. Standardised va...
Three geothermal direct heat applications were examined to derive a set of cost estimates from which one could determine the effect of changes in system parameters (temperature, flow, load, etc.) on the cost of heat. For each application, a set of resource characteristics and system inputs were chosen to best represent a site specific baseline condition. The baseline estimated cost of heat was calculated along with other cost estimates representing optimistic and pessimistic conditions, bracketing the range any input variable might reasonably take. Regression equations based upon these cost estimates were developed for each application to quantitatively relate changes in cost to changes in the input variables. These three equations and their accompanying nomographs serve as easily understandable planning tools for direct heat geothermal energy projects.
Energy harvesting systems stimulate the development of power management for low power consumption applications. Improving the converter efficiency of power management circuits has become a significant issue in energy harvesting system design. This paper presents a variable step-down conversion ratio switched capacitor (SC) DC-DC converter to advance the converter efficiency of charge on the stored capacitor in a wireless monitoring system of orthopedic implants. The converter is designed to work at 1 MHz switching frequency and achieves 15 to 2 V conversion. Measurement results show that the converter efficiency can reach 42% including all circuit power consumption, which is much higher than previous work. (semiconductor integrated circuits)
Abstract Objective:- This study explored 12-month outcome and its associations to social adjustment-related variables in patients with first-episode non-affective psychosis in Finland and Spain. Methods:- Forty-nine Finnish and 37 Spanish patients were evaluated at admission on various characteristics of social adjustment. Outcome was measured for 68 (79%) patients by the Brief Psychiatric Rating Scale, Global Assessment Scale, and Grip on Life. Results:- One-fourth of the patients experienced psychotic symptoms at follow-up. Sixty per-cent of the patients showed good global functioning and Grip on Life. In both patient groups, poor earlier global functioning, weak social network, poor Grip on Life, and psychological dependence on family of origin were associated with poor outcome. In the ...
A fermentation waste, Corynebacterium glutamicum, was successfully employed as a biosorbent for Reactive Black 5 (RB5) from aqueous solution. This paper initially studied the effect of pretreatment on the biosorption capacity of C. glutamicum toward RB5, using several chemical agents, such as HCl, H{sub 2}SO{sub 4}, HNO{sub 3}, NaOH, Na{sub 2}CO{sub 3}, CaCl{sub 2} and NaCl. Among these reagents, 0.1 M HNO{sub 3} gave the maximum enhancement of the RB5 uptake, exhibiting 195 mg/g at pH 1 with an initial RB5 concentration of 500 mg/l. The solution pH and temperature were found to affect the biosorption capacity, and the biosorption isotherms derived at different pHs and temperatures revealed that a low pH (pH 1) and high temperature (35 deg. C) favored biosorption. The biosorption isotherm was well represented using three-parameter models (Redlich-Peterson and Sips) compared to two-parameter models (Langmuir and Freundlich models). As a result, high correlation ...
A multielement apparatus for the removal of aerosols formed in the vitrification of simulated high-activity accident wastes from the decommissioned nuclear power plant A-1 has been designed, manufactured and tested. The apparatus consists of two cooling and condensing steps connected in series, and of five filtration steps also connected in series. The five filtration steps allowed to achieve a decontamination factor of 1x10"5 in the case of removal of a NaCl("2"4Na) testing model aerosol. The decontamination factor for removal of the cesium aerosol by the whole apparatus was 3.3x10"6. In the first filtration step the aerosols are removed by the cartridge with a filtration fabric made of polyethylene fibers, in the second step by the cartridge with a granulated natural material, in the third step by the cartridge with glass-fiber filtration paper, in the fourth and fifth steps by the cartridge with high-efficiency filtration paper made of glass microfibers. In the ...
By magnetron sputtering model steel films with specific properties can be prepared for purposive surveys. By changing the deposition parameters certain properties of these films can be influenced. For this thesis steel films with 18% Cr and 8% Ni have been prepared in order to study specific parameters on the corrosion resistance of bulk stainless steel. Chemical composition, microstructure, and surface morphology of these films have been characterized. In comparison to bulk steel sheets with the same chemical composition they have a smaller grain size and a ferritic structure. In contrast to bulk steel sheets they don`t contain any nonmetallic inclusions like Mn-sulfides. The influence of these structural differences on the corrosion resistance has been studied. For this purpose the electrochemical properties of the sputter-deposited steels have been compared with the properties of steel sheets with a similar chemical composition (DIN 1.4301, AISI 304) in neutral and acidic Cl{sup ...
Neurodegeneration observed in Alzheimer disease (AD) is believed to be related to the toxicity from reactive oxygen species (ROS) produced in the brain by the amyloid-{beta} (A{beta}) protein bound primarily to copper ions. The evidence for an oxidative stress role of A{beta}-Cu redox chemistry is still incomplete. Details of the copper binding site in A{beta} may be critical to the etiology of AD. Here we present the structure determined by combining x-ray absorption spectroscopy (XAS) and density functional theory analysis of A{beta} peptides complexed with Cu{sup 2+} in solution under a range of buffer conditions. Phosphate-buffered saline buffer salt (NaCl) concentration does not affect the high-affinity copper binding mode but alters the second coordination sphere. The XAS spectra for truncated and full-length A{beta}-Cu{sup 2+} peptides are similar. The novel distorted six-coordinated (3N3O) geometry around copper in the A{beta}-Cu{sup 2+} complexes include ...
The sol-gel-immobilized Tris(2,2'-bipyridyl)ruthenium(II) [Ru(bpy)_3 "2"+] electrogenerated chemiluminescence (ECL) sensor was applied to the reversed-phase high-performance liquid chromatography (HPLC) determination of phenothiazine derivatives (promazine, chlorpromazine, triflupromazine, thioridazine, and trifluoperazine) and erythromycin in human urine samples. In this method, Ru(bpy)_3 "2"+ was immobilized in sol-gel-derived titania (TiO_2)-Nafion nanocomposite films coated on a dual platinum electrode. This method eliminates an extra pump needed for the delivery of Ru(bpy)_3 "2"+ reagent into a reaction/observation zone in front of photomultiplier tube because the immobilized-Ru(bpy)_3 "2"+ is recycled on the electrode surface by an applied potential at +1.3 V versus Ag/AgCl (3 M NaCl) reference electrode. The resulting analytical performances such as detection limit, working range, sensitivity, and measurement precision were slightly worse than those obtained ...
The sol-gel-immobilized Tris(2,2'-bipyridyl)ruthenium(II) [Ru(bpy){sub 3} {sup 2+}] electrogenerated chemiluminescence (ECL) sensor was applied to the reversed-phase high-performance liquid chromatography (HPLC) determination of phenothiazine derivatives (promazine, chlorpromazine, triflupromazine, thioridazine, and trifluoperazine) and erythromycin in human urine samples. In this method, Ru(bpy){sub 3} {sup 2+} was immobilized in sol-gel-derived titania (TiO{sub 2})-Nafion nanocomposite films coated on a dual platinum electrode. This method eliminates an extra pump needed for the delivery of Ru(bpy){sub 3} {sup 2+} reagent into a reaction/observation zone in front of photomultiplier tube because the immobilized-Ru(bpy){sub 3} {sup 2+} is recycled on the electrode surface by an applied potential at +1.3 V versus Ag/AgCl (3 M NaCl) reference electrode. The resulting analytical performances such as detection limit, working range, sensitivity, and measurement ...
Removal of radioactive ions was studied from low and medium level radioactive waste solutions by electrodialysis using ion exchange membranes. The test solutions contained "1"3"7Cs"+, "1"0"6Ru"3"+ or fission products (F.P.) as active ions and NaCl, Na_2SO_4 or Ca(NO_3)_2 as inactive coexisting salts. The decontamination factor of the active ions was in the order: "1"3"7Cs"+ (greater than 99%) > "9"0Sr"2"+ > F.P. > "1"0"6Ru"3"+. The dialysis time required to attain the saturation was the shortest for monovalent cations K"+, Cs"+ and Na"+, intermediate for divalent cation Sr"2"+, and the longest for trivalent cation Ru"3"+. The ratio of the decontamination factor of an active ion eta sub( a) to the desalination factor of an inactive ion eta sub( b) was nearly equal to unity for "2"4Na, "4"2K, "1"3"7Cs and "9"0Sr. On the other hand, the apparent selective permeability of an active ion (A"+) against Na"+ ion, T sub(Na"+) sup( a) was higher than unity for all ...
To evaluate a dose conversion factor from the `Working Level of Month` (WLM) of radon to the absorbed dose (mGy), the quality of radon and its progeny was assessed, and exposures controlled for each deposition region were planed as follows: 1) exposure of radon gas to the entire respiratory tract, 2) exposure of `unattached` fractions to the upper respiratory tract, 3) exposure of `attached` fractions onto ultrafine particles to the deep lung, 4) exposure of `attached` fractions onto fine particles to the lower respiratory tract, 5) exposure of `attached` fractions onto coarse particles to the upper respiratory tract. In this preliminary study, a prototype exposure system of radon and its progeny for small rodents was designed. A whole body exposure chamber with a volume of about 0.5 m{sup 3} was used, which it held 20 rats. The aging and mixing chamber separated by the exposure chamber had a volume of about 1 m{sup 3}. As career aerosols of radon progeny, carnauba wax aerosols as ...
The electrochemical dissolution behaviour of armco-iron and of the steels C15, C45, C60 and 100Cr6 in concentrated sodium chloride media has been investigated. Anodic metal dissolution experiments have been carried out using the flow channel cell (parallel plate reactor), the rotating cylinder electrode (RCE) and the capillary cell. The microstructure of the steel has been varied through variation of carbon content and heat treatment (e.g. soft annealed with globular carbides or pearlitic). Current-efficiency values have been obtained by gravimetric measurements in the current-density range from i=5 to 60 A/cm{sup 2}. For the soft annealed steels, the divalent ferrite dissolution in combination with electroless cementite removal dominates. For the pearlitic steels, the occurrence of oxygen evolution electronically conductive metal carbides or trivalent ferrite dissolution, depending on the current density applied, was detected. Microstructure dependent potentiostatic current transients ...
The objective of the study was the kinetic modeling of the effect of storage temperature on the quality and shelf life of chilled fish, modified atmosphere-packed (MAP), and osmotically pretreated with the addition of nisin as antimicrobial agent. Fresh gilthead seabream (Sparus aurata) fillets were osmotically treated with 50% high dextrose equivalent maltodextrin (DE 47) plus 5% NaCl. Water loss, solid gain, salt content, and water activity were monitored throughout treatment and treatment conditions were selected for the shelf life study. Untreated and osmotically pretreated slices with and without nisin (2 x 10(4) IU/100 g osmotic solution), packed in air or modified atmosphere (50% CO(2)-50% air), and stored at controlled isothermal conditions (0, 5, 10, and 15 degrees C) were studied. Quality assessment and modeling were based on growth of several microbial indices, total volatile nitrogen, trimethylamine nitrogen, lipid oxidation (TBARS), and sensory ...
In order to investigate the role of amorphous SiO{sub 2} particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO{sub 2} particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO{sub 2} was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO{sub 2} particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of {gamma}-phase and amorphous nano-SiO{sub 2} particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO{sub 2} particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. ...
In order to investigate the role of amorphous SiO2 particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO2 particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO2 was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO2 particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of ?-phase and amorphous nano-SiO2 particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO2 particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. Compared with single alloying layer, the ...
Pitting crevice and intergranular corrosion resistances of titanium-modified low-carbon austenitic stainless steel with a nominal composition of 15% Cr, 15% Ni, 0.24% Ti and 2.5% Mo were found superior to conventional type 316 SS. Potentiodynamic anodic polarization studies in a neutral chloride medium (0.5M NaCl solution) and the immersion studies in boiling solution containing (by wt%) 11% H_2SO_4 + 3% HCl + 1% CuCl_2 + 1% FeCl_3 for 24 h showed higher critical pitting and crevice potentials and lower corrosion rate values respectively. The elemental composition across the pit sites was also determined by EPMA analysis. Sensitization studies carried out by following ASTM A262 practices A and E and electrochemical potentiokinetic reactivation (EPR) tests on this alloy heat treated at 923 K for 1 and 50 h showed a better resistance to intergranular corrosion than that for conventional type 316 SS. From the results available, the most likely reason for the ...
Minor M (M = Fe, Mn, Cr) additions are widely added to enhance the corrosion resistance of commercial cupronickel alloys. The present paper aims at optimizing the amounts of M in Cu_7_0(Ni,Fe,Mn,Cr)_3_0 (at.%) alloys using a cluster-plus-glue-atom model for stable solid solutions. By this model, it assumed that 1 M atom and 12 Ni atoms formed an M-centered and Ni-surrounded cube-octahedron cluster and the isolated M_1Ni_1_2 clusters are embedded in a Cu matrix, conforming to a cluster formula [M_1Ni_1_2]Cu_3_0_._3 = [M_1_/_1_3Ni_1_2_/_1_3]_3_0Cu_7_0. A structure of this kind satisfies ideally the nearest neighbor requirement, i.e. only M-Ni and Ni-Cu neighbors are allowed and the unfavorable Cu-M pairs are avoided, and hence it describes a stable solid solution structure with good thermal stability. Electrochemical corrosion measurements indicated that [(Fe_0_._6Mn_0_._2_5Cr_0_._1_5)_1Ni_1_2]Cu_3_0_._3 had the best corrosion resistance in 3.5% NaCl aqueous ...
The present study was designed to investigate, in more detail, the mechanism of lead transport by the gastrointestinal tract and particularly the similarities or dissimilarities between lead and calcium in this process. The absorption of these metals was determined in 3-week-old white Leghorn cockerels, raised on a commercial diet or special diets, using an in vivo ligated loop procedure. The dose administered into the loop usually contained 0.5 ..mu..Ci /sup 203/Pb (and/or 0.1 ..mu..Ci /sup 47/Ca), 0.01 mM lead acetate (and/or 1 mM CaCl/sub 2/) in 0.5 ml of 0.15 M NaCl, pH 6.5. It was shown that lead is rapidly taken up by the intestinal tissue, and only slowly transferred into the circulation whereas calcium, also accumulated rapidly by the tissue, is rapidly released from the tissue in the serosal direction. The absorption processes of these cations show similar responses to various experimental conditions (low calcium intake, age of the animal, pH of the dosing ...
The concentration of trace elements in brain sections was measured by synchrotron radiation X-ray fluorescence. The relative concentration was calculated by means of the normalization of Compton scattering intensity approximately 22 keV, after the normalization for collecting time of X-ray spectrum and the counting of the ion chamber, and subtracting the contribution of the polycarbonate film for supporting sample. Furthermore, the statistical evaluation of the element distribution in various regions of the brain sections of the 20-day-old rats was tested. For investigating the distribution of elements in the brain of iodine deficient rats, Wistar rats were fed with iodine deficient diet and deionized water (ID group). The rats were fed the same iodine deficient diet, but drank KIO_3 solution as control (CT group). The results showed that the contents of calcium (Ca) in thalamus (TH) and copper (Cu) and iron (Fe) in cerebral cortex (CX) of ID rats were significantly lower than that of ...
Passivity of aluminum (Al) alloy 3003 in air and in aqueous solutions without and with chloride ions was characterized by electrochemical measurements, including cyclic polarization, electrochemical impedance spectroscopy (EIS), localized EIS and potential of zero charge, Mott-Schottky analysis and secondary ion mass spectroscopy (SIMS) technique. Stability, pitting susceptibility and repassivation ability of Al alloy 3003 under various film-forming conditions were determined. Results demonstrated that passive films formed on 3003 Al alloy in air and in Na2SO4 solution without and with NaCl addition show an n-type semiconductor in nature. The passive film formed in chloride-free solution is most stable, and that formed in chloride-containing solution is most unstable, with the film formed in air in between. Pitting of Al alloy 3003 passivated both in air and in aqueous solutions is inevitable in the presence of chloride ions. There is the strongest capability for ...
The effect of uniaxial tensile stress on intergranular corrosion (IGC) of AA2024-T3 was studied using the foil penetration technique. Standard ASTM G49 fixed-displacement jigs were modified to allow the use of sheet samples, which were then attached to an electrochemical cell as in the foil penetration setup. The time for IGC to penetrate samples of varying thickness was monitored. This method provides a new approach to bridge the gap between IGC and intergranular stress corrosion cracking (IGSCC). Samples with various orientations relative to the rolling direction were studied in 1.0 M NaCl at controlled anodic potentials. Potentiodynamic polarization measurements indicated that the two breakdown potentials typically observed for AA2024-T3 were lower for stressed samples than for unstressed samples, and the current at a given potential was higher. The penetration rate depended on potential and was higher for stressed samples than for unstressed samples. The ...
To study the fatigue life of extruded AZ31 (3%Al, 1%Zn, 0.3%Mn, Mg - the rest), AM50 (5%Al, 0.4%Mn, Mg - the rest) and ZK60 (5%Zn, 0.5%Zr, Mg - the rest) Mg alloys in air and NaCl-based solutions, corrosion fatigue tests were carried out using a rotating beam type fatigue machine. For the analysis of the corrosion fatigue behavior of Mg alloys in different environments, fitted N{sub sol}/N{sub air} ratio considered as a relative corrosion fatigue life is used. Here N{sub sol} and N{sub air} are the numbers of cycles to failure in the solution and in air, respectively. An extruded ZK60 alloy shows very high fatigue and corrosion fatigue properties in comparison with other alloys. However, ZK60 shows the lowest values of the relative fatigue life (N{sub sol}/N{sub air} {proportional_to}10{sup -3}-10{sup -2}) compared to that for AM50 and AZ31 alloys (N{sub sol}/N{sub air} {proportional_to}10{sup -2} - 10{sup -1}). Generally, extruded alloys in comparison to earlier studied die-cast ...
We use the conductimetric method, adequate to electrolytes, to determine the lysozyme charge in lys-water and ternary lys-salt-water systems. We measured also the viscosities for the above binary and ternary systems in the same conditions at pH$=4.5$ and T$=298$ K, measurements that allow us to see any effect of viscosity on cations mobilities and implicitly on the lysozyme charge. The method is illustrated for the lysozyme chloride aqueous solution system at 25$^o$ C, using the data reported here for pH$=4.5$ at 0.15, 0.6, 0.8, 1., 1.5, 2., 2.5, 3., 3.5 mM (mg/mL) lysozyme chloride concentrations. The method was also applied to ternary lys-salt-water systems in the same conditions at pH$=4.5$ and T$=25^o$ C. Ternary conductivities are reported for a mean concentration 0.6 mM of lysozyme chloride in all systems and a mean concentration 0.01, 0.025, 0.05, 0.1, 0.175, 0.2, 0.5, 0.7, 0.9, 1.2, 1.3 and 1.4 M for NaCl; 0.005, 0.01, 0.05, 0.1, 0.175, 0.2, 0.5, 0.7, 0.9, ...
Pitting corrosion and trans-passive dissolution of 316 stainless steel in solution containing five percent of commercial bleaching liquid was investigated by employing potentiodynamic polarization method and recording corrosion potential during immersion. Today commercial bleaching liquids are widely used as cleaner additives, therefore, those house appliances made from stainless steels are in contact with aqueous solution containing bleaching liquid. This may cause sever localized corrosion and trans-passive dissolution. In order to investigate the possibility of trans-passive dissolution of stainless steel by bleaching liquid, potentiodynamic polarization and recording variation of corrosion potential of specimens were carried out in 0.2 M Na{sub 2}SO{sub 4} solution containing 5 %wt. commercial bleaching liquid. A 500 mV drop in trans-passive potential and also instantaneously ennobling corrosion potential revealed the possibility of trans-passive dissolution due to oxidizing effect ...
The diffusion of alkali vapours in the anode compartment of a DIR-MCFC produces the deactivation of the internal reforming catalyst. Sets of ceramic porous membranes purposed to limit the diffusion have been manufactured by different techniques and the influence of the preparation technique and of the preparative variables on the morphological characteristics of the membranes structures has been studied.
This work has analyzed the key variables of indentation tip radius, contact radius, delamination radius, residual stress and superlayer/film/interlayer properties on nanoindentation measurements of adhesion. The goal to connect practical works of adhesion for very thin films to true works of adhesion has been achieved. A review of this work titled ''Interfacial toughness measurements of thin metal films,'' which has been submitted to Acta Materialia, is included.
Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.
This article describes the state-of-the-art HVAC system at the Philadelphia Marriott Hotel. Thermal comfort and indoor air quality are emphasized. The system uses a hybrid gas absorption/electric centrifugal chilled water plant, variable flow pumping, water-side economizers to provide free cooling, central air handling units with air-side economizers and flow monitoring equipment.
This paper propose to show the technical and economic aspects of the implementation of small power distribution systems in small rural properties in some locations of Argentina. This paper presents a concrete methodology, with a rational cost composition and introduces project variables. 4 figs.
Given a random variable $F$ regular enough in the sense of the Malliavin calculus, we are able to measure the distance between its law and almost any continuous probability law on the real line. The bounds are given in terms of the Malliavin derivative of $F$. Our approach is based on the theory of It\\^o diffusions and the stochastic calculus of variations. Several examples are considered in order to illustrate our general results.
This book comprises an up-to-date description of the astrophysical characteristics of the sun, including modern techniques used in solar research. Provides an historical background of solar research and techniques and covers the necessary astrophysics for solar studies, energy generation in the interior, the convection zone, the non- thermally heated layers, and solar wind are described in detail. Also considers the sun in relation to other stars, including information on its variable outputs of light, charged particles, and fields.
Cellulose raw materials costs must be considered in order to obtain a minimized hexose cost. In recognition of this fact, it may be economically advantageous to operate at less than maximum hexose concentration in the reactor and to recycle unreacted cellulose. The objective of this article is to optimize a cellulose-recycle reactor system for producing hexose at minimum cost. A sensitivity analysis of the important variables in the mathematical model of this system is also discussed.
After a brief survey of the known level measurement methods the particularities of the radiometric measurement of the still utilisable residual volume of a bulk material in a large bin are discussed. At constant angle of repose the measurement in a suitably positioned plane of measurement suffices, at variable angle of repose two planes of measurement are required. The probable working ranges for a 1300-t lime bin are estimated.
Resistance exercise has been widely reported to have positive rehabilitation effects for patients with neuromuscular and orthopaedic conditions. This paper presents an optimal design of magneto-rheological fluid dampers for variable resistance exercise devices. Adaptive controls for regulating the resistive force or torque of the device as well as the joint motion are presented. The device provides both isometric and isokinetic strength training for various human joints.
Wax appearance temperature (WAT) of three petroleum waxes in different solvent systems under varying thermal conditions has been determined. It is observed that this temperature mainly is a function of the concentration of the wax and the solubility parameter ([delta]) of the solvent taken. This dependence of WAT has been quantified in terms of these variables in the form of mathematical equation and nomographs. (orig.)
One of the main goals in the operation of a cupola furnace is to keep the molten iron properties within prescribed bounds while maintaining the most economical operation for the cupola. In this paper the authors present a procedure to obtain the nominal values for the manipulated process variables. The nominal values are calculated by solving a constrained nonlinear programming optimization problem. Two different optimization problems are discussed and examples for using the procedure are presented.
Plasma confinement by permanent magnets has been studied. An analytic formula for the field of a single bar magnet has been obtained. Generalization to various configurations of multidipole fields has also been found. Any two-dimensional field may now be completely described by a simple function of complex variables in closed form. Vector potential has also been obtained by integrating over a prescribed Riemann surface. The confinement of plasma by multidipole fields then becomes obvious through conservation principles.
This paper outlines the development of an organizational model which will be used to determine the influence of supervisory and management functions in a nuclear power plant (NPP) on risk. A theoretical conceptualization, derived from the empirical literature, is used to describe the organizational structure of NPPs. The parameters and variables associated with this dynamic, process-oriented model are detailed. Applications of the model and preliminary insights derived from this conceptualization are discussed.
A mathematical model is proposed for three-phase filtering which is a particular case of a more general model of filtering multiple component mixtures and makes it possible to describe three-phase filtering flows under conditions where the pressure of saturation is variable in time and in space. In the proposed model, the system of unknown functions is selected so that it makes it possible to trace fairly simply the pressure of saturation and to compute the corresponding equation coefficients.
A mathematical and physical model was constructed describing the hydrodynamics of the two-phase mixture in the horizontal steam generator. The HP 9830 A desk-top calculator was used for the computations. The output variable of the solution was the level shape. A quantitative and qualitative comparison was made of the results of computations and experimental data. (author).
The Variable Dynamic Testbed Vehicle (VDTV) is presently being developed by the National Highway Traffic Safety Administration (NHTSA). It is being designed to have a steer-by-wire front steering system and an independent rear steering system. These steering systems enable the VDTV to emulate the directional control characteristics of a broad range of passenger vehicles.
We report the of the existence of RV Tauri stars in the Large Magellanic Cloud (LMC). This class of variable star has hitherto been unidentified in the Magellanic Clouds. In light and color curve behavior the RV Tauri stars appear to be an extension of the Type II Cepheids to longer periods. A single period-luminosity-color relationship is seen to describe both the Type II Cepheids and the RV Tauri stars in the LMC.
The long-range correlation properties in the hourly time variability of geochemical signals measured in a 70 m depth well at Triponzo (Umbria region), are investigated by the detrended fluctuation analysis (DFA). DFA is a data processing method that allows for the detection of scaling behaviors in observational time series even in the presence of non-stationarities. The procedure adopted has allowed for the unambiguous identification of possible correlations among the recorded signals and local earthquakes.
The feasibility of using a thermoplastic-powder metallurgy technique for the fabrication of porous niobium rods was investigated. Some early problems were overcome to successfully extrude the polymer coated niobium powder into long lengths. The effects of certain process variables were investigated. Residual porosity and extrusion pressure were found to be regulated by the polymer fraction. The procedures for taking the extruded polystyrene--niobium rods through the heat treatments to the final, tin infiltrated stage are explained.
It is shown that a sufficient condition for a model describing the motion of a particle on a coset space to possess a Fundamental Poisson bracket Relation, and consequently charges in involution, is that it must be a symmetric space. The conditions, a Hamiltonian, or any functions of the canonical variables, has to satisfy in order to commute with these charges, are studied. It is show that, for the case of the noncompact symmetric spaces, these conditions lead to an algebraic structure which lays an important role in the construction of conserved quantities.
The hierarchy of integrable nonlinear equations associated with the quadratic bundle is considered. The expressions for the solution of linearization of these equations and their conservation law in the terms of solutions of corresponding Lax pairs are found. It is shown for the first member of the hierarchy that the conservation law is connected with the solution of linearized equation due to the Noether's theorem. The local hierarchy and three nonlocal ones of the infinitesimal symmetries and conservation laws explicitly expressed through the variables of the nonlinear equations are derived. (author)
Multiple linear regression, principal component analysis, partial least squares, polynomial regression and artificial neural networks are popular techniques for process modeling. An industrial case study illustrates some of these technologies, with an emphasis on artificial neural networks. Experience with this and other projects indicates that while neural network models, combined with partial least squares when necessary, are an excellent tool for modeling, linear techniques may also be appropriate in some cases. Regardless of the specific method used, software analyzers are an attractive lower-cost alterative to hardware options in some monitoring applications. From a fundamental point of view, the result of chemical analysis can be considered as the dependent variable(s) of a process system having a number of independent variables. The independent variables are the causes and the chemical analysis is the effect. If the ...
Biomedical science researchers often express frustration that health physics practices vary widely between individual institutions. A survey examining both internal and external dose assessment practices was devised and mailed to fifty institutions supporting biomedical science research. The results indicate that health physics dose assessment practices and policies are highly variable. Factors which may contribute to the degree of variation are discussed. 2 tabs.
BackgroundThe beta-defensin gene cluster (DEFB) at chromosome 8p23.1 is one of the most copy number (CN) variable regions of the human genome. Whereas individual DEFB CNs have been...Full Text Available
Analyzing the risk of a safeguards system, in particular the security of a computer network based on the notion of fuzzy sets and linguistic variables, addresses concerns such as complexity and inherent imprecision in estimating the possibility of loss or compromise. Automated risk analysis allows the risk to be determined for an entire system based on estimates for lowest level components and the component weight. In addition, for each component (asset) we select the most effective combination of protection mechanisms against a given set of threats.
The theoretical evolution of a horizontal branch star of Population II is followed through the helium burning in the core phase and is compared with the results given by other investigators. The m- fluence of different physics and interpolation schemes in the opacity tables is discussed. Some thoughts are given on the explanation of the erratic period variations observed in some of the RR Lyrae variables in the globular clusters. (auth)
BackgroundStudies of chronic health effects due to exposures to particulate matter with aerodynamic diameters ≤ 2.5 μm (PM2.5) are often limited by sparse...Full Text Available
We propose a scheme able to generate stationary continuous variable entanglement between an optical and a microwave cavity mode by means of their common interaction with a micro-mechanical resonator. We show that when both cavities are intensely driven one can generate bipartite entanglement between any pair of the tripartite system, and that, due to entanglement sharing, optical-microwave entanglement is efficiently generated at the expense of microwave-mechanical and opto-mechanical entanglement.
Energy conservative building design has triggered greater interests in developing flexible and sophisticated air conditioning systems capable of achieving enhanced energy-savings potential without sacrificing the desired thermal comfort and indoor air quality (IAQ). This research work greatly aimed at achieving enhanced energy conservation, good thermal comfort and better IAQ for space conditioning with the application of combined variable refrigerant volume (VRV) and variable air volume (VAV) air conditioning (A/C) systems. Experimental investigation on the proposed combined air conditioning system with the application of intelligent fuzzy logic controller was performed for summer and winter climatic conditions to substantiate the energy-savings capability. The proposed system experimentally analyzed under fixed ventilation, demand controlled ventilation (DCV) and combined DCV and economizer cycle (EC) ventilation techniques effectively ...
Protocol changes and options contained within US Environmental Protection Agency whole effluent toxicity tests represent variables that have the potential to affect bioassay performance and interpretation of results. Variables evaluated in this study include: the change in allowable age in the Pimephales promelas acute bioassay from up to 90 d to a maximum of 14 d, age-specific acute responses of P. promelas among the allowable ages of 1 to 14 d, change in the chronic growth endpoint definition from final mass to biomass, differences between hemacytometer and fluorometer measurements in the Selenastrum capricornutum protocol, and options for statistical interpretation of species sensitivity in multiple test/species screening bioassays. Clear age-related sensitivity and precision differences were observed in acute responses of P. promelas. Results obtained using the younger age classes were typically more variable in studies ...
Electrochemical cyclic potentiodynamic polarization (CPP) experiments were performed on several candidate high-performance waste package container materials to evaluate their susceptibility to localized corrosion in aqueous environments relevant to the potential underground high-level nuclear waste repository. This paper presents the results of this study showing the effects of chloride ion (Cl) concentrations, pH, temperature, and electrochemical potential scan rate on the pitting corrosion behavior of these materials.
We propose a continuum description for the axial separation of granular materials in a long rotating drum. The model, operating with two local variables, concentration difference and the dynamic angle of repose, describes both initial transient traveling wave dynamics and long-term segregation of the binary mixture. Segregation proceeds through ultraslow logarithmic coarsening. {copyright} {ital 1999} {ital The American Physical Society}
ABSTRACTThe immune response to Neisseria gonorrhoeae is poorly understood, but its extensive antigenic variability and resistance to complement are thought to allow it...Full Text Available
An unusual S1-nuclease sensitive microsatellite (STMS) has been found in the single copy, rat polymeric immunoglobulin receptor gene (PIGR) terminal exon. In Fisher rats, elements within or beyond the...Full Text Available
Cystic fibrosis (CF) is a monogenic disease characterized by a high variability of disease severity and outcome that points to the role of environmental factors and modulating genes that shape the course...Full Text Available
DescriptionThe main objective of the project is to develop a range of underpinning plant resources together with information about the level of genetic variability they represent, in a form suitable for use in crop improvement research in vegetable brassicas, lettuce and onion. The proposed research addresses Defra's requirement for a crop improvement programme to underpin research programmes aimed at Pest and Disease Control, Plant Nutrition and Quality in field vegetables at HRI. We will produc [continued...
A non-recursive model is proposed and empirically tested with data of opponents of nuclear power. In explaining conventional and unconventional participation the theory of collective action is applied and modified in two respects: the perceived influence on the elimination of collective evils are taken into account; the selective incentives considered are non-material ones. These modifications proved to be valid: the collective good variables and non-material incentives were important determinants for the two forms of participation. Another result was that there is a reciprocal causal relationship between conventional and unconventional participation.
This demonstration project uses modern simulation techniques to illustrate the important technologies and design variables that an auto-designer would consider in production a high efficiency, low emissions vehicle. Simulation and modeling techniques use the idea of capturing the relationships between real components of the systems with mathematical equations. These equations are then solved on a computer to simulate the behavior or performance of the system under various conditions. In the current demonstration project, we focus on many variations of a hydrogen-powered vehicle.
The possible existence of preferential B-site disorder in A-15 compounds recently claimed on the basis of x-ray powder diffraction data but questioned from the viewpoint of known phase diagrams is examined for some Nb-based compounds of this type. It is concluded that x-ray powder data do not allow the determination of both order and compositional variables as suggested, and the latter must therefore be determined by some other method. (author).
Canonical gravity in real Ashtekar-Barbero variables is generalized to allow for fermionic matter. The resulting torsion changes several expressions in Holst's original vacuum analysis, which are explicitly displayed here. This in turn requires adaptations to the known canonical (loop) quantization of gravity coupled to fermions, which is discussed on the basis of the classical analysis.
RP-1 is a long-established hydrocarbon fuel that continues to be widely used as the kerosene component in rocket propulsion systems. The desire in recent years to use rocket motors many times, rather than a single time, has led to reformulations of RP-1. ...
The catalytic liquefaction of a Chinese bituminous coal was simulated by artificial neural network. Three liquefaction variables, catalyst loading, reaction temperature and reaction time were used as inputs and tetrohydrofuran (THF) conversion and toluene (T) conversion were used as outputs. The artificial neural network, trained by the experimental data, could represent the liquefaction process, with a mean squared deviation of less than 0.025. 7 refs.,1 fig., 3 tabs.
The report gives results of a pilot-plant study of the ammonia absorption/ammonium bisulfate regeneration process for removing SO2 from the stack gas of coal-fired power plants. Data were developed on the effects of such operating variable in the absorption of SO2 by ammoniacal l...
1. The aim of the paper is to investigate the relative importance of three sets of sources of competitive advantages on business performance in a specific industry context, ie the European meat processing industry. The three sets of competitive sources are Firm Specific Advantages (FSAs), Localizational Specific Advantages (LSAs) and Relationship Specific Advantages (RSAs). Based on a literature study, each set of competitive advantages is briefly described in terms of their theoretical antecedents. Seven hypotheses are formulated regarding the direct as well as the indirect relationships between the FSAs, LSAs and RSAs and business performance. Also, the direction of causality between the various sets of explanatory variables is considered. The hypotheses are combined in a structural modelling of firm competition. 2. Data and measurements are derived from a survey in the European meat processing industry in which 133 meat processors from 10 EU countries agreed to ...
Passive films were formed on chromium by polarization at +400 mV/SHE in 0.5 M H{sub 2}SO{sub 4} for different times (30 minutes, 2 hours and 20 hours) without and with chlorides. The effect of chlorides was studied by adding NaCl to the solution before or after passivation. The chloride concentrations were 0.05, 0.3 and 1 M. The (i-E) curves recorded for Cr without and with Cl{sup -} are similar and the addition of chlorides after passivation has no significant effect on the current recorded in the passive state. The passive films were analyzed by angle-resolved XPS (AR-XPS). The measurements performed at different take-off angles of the photoelectrons show that the films have a bilayer structure constituted of an outer hydroxide layer, Cr(OH){sub 3}, and an inner oxide layer, Cr{sub 2}O{sub 3}. The thicknesses of the oxide and hydroxide layers are 3 A and 9 A, 6 A and 7 A and 6 A and 6 A for the films formed in 0.5 M H{sub 2}SO{sub 4} after 30 minutes, 2 hours and ...
Aim: Compounds such "9"9"mTc-MDP and "9"9"mTc-HEDP are used regularly in bone scintigraphy for metastasis detection. The therapeutics properties of beta emitter radionuclides like "1"5"3Sm, "1"6"6Ho and "1"7"7Lu has been widely reported in literature being "1"7"7Lu the less developed for medical applications. With the purpose of study different radiopharmaceuticals alternatives, for metastasis bone palliation, we have evaluated, on a comparative basis, the labeling of "1"5"3Sm-MDP, "1"5"3Sm-HEDP, "1"6"6Ho-MDP, "1"6"6Ho-HEDP, "1"7"7Lu-MDP and "1"7"7Lu-HEDP from the exhibited radionuclidic purity and biological distribution point of view. Material and Methods: The radionuclides were produced at La Reina Research Reactor, Chilean Nuclear Energy Commission. The radionuclidic purity was determined by gamma-Ray spectrometry. The labeling was accomplished with MDP (Plenum) and HEDP synthesized in-house. The in-vitro affinity of labeled compounds to the mineral bone matrix was determined using ...
In the Ti-Si-C and Ti-Si-C-N systems, metastable layers were precipitated by means of non-reactive magnetron sputtering of hot-pressed two-phase TiC/SiC and TiN/SiC targets with 20 mole% and 50 mole% SiC. The preparation parameters were varied as follows: ion bombardment during precipitation (bias sputtering), substrate temperature, and annealing times when annealing amorphous 50%:50% TiC/SiC and 50%:50% TiN/SiC layers. Sputtering of targets containing 20% SiC was found to result in monophase fcc layers (NaCl structure). This was documented on the basis of X-ray and electron diffraction patterns. Direct precipitation of targets with 50 mole% SiC resulted in amorphous layers. Increasing the ion bombardment during accretion, raising the substrate temperature, and annealing amorphous 50%:50% TiC/SiC and 50%:50% TiN/SiC (layers precipitated directly) resulted in the crystallization of TiC and TiN nanocrystallites, respectively, imbedded in an amorphous SiC matrix. ...
It is well known that contact with metals can be responsible for allergic contact dermatitis; also, there is experimental evidence that nickel ions are readily available on the surface of used coins containing nickel and copper. The aim of this study was to prove that metal powders of nickel (Ni), cobalt (Co) and chromium (Cr) dispersed in synthetic sweat are oxidised into respective ions that can permeate the skin. Suspensions of 5 g of metal powder (Ni, Co and Cr) in 100 mL of synthetic sweat at pH 6.5 were prepared and shaken with a stirring plate at room temperature for 30 min. Human skin membranes were set up in Franz-diffusion cells and 2 mL of the freshly made suspension were applied to the outer surface of the skin for 24h. The appearance of metal ions in the aqueous receptor phase (NaCl 0.9%) was quantified by Electro Thermal Atomic Absorption Spectroscopy (ETAAS). Also, metals ions were analysed using Differential Pulse Polarography (DDP), Differential ...
For evaporation crystallization of extremely corrosive FGD scrubber solutions which - depending on the process - can lead all the way to a product suitable for depositing, an economic equipment concept based on metallic construction materials was to be investigated. In a parameter study, electrochemical test methods were used to determine the influence of the pH value, the Fe{sup 3+}, F and So{sub 2} contents in a solution containing 200 g/l CaCl{sub 2}+30 g/l NaCl at 80deg C on the resistance to pitting corrosion of stainless steels and NiCrMo alloys. In addition, electrochemical and wet corrosion tests (e.g. crevice corrosion) were conducted using original FGD scrubber solutions with 43-50% dry substance from the power plants Reuter-West, Oberhavel and Rudow of the BEWAG, Berlin. The results were compared to those of standardized and non-standardized short-term tests for determining the critical pitting corrosion and crevice corrosion temperatures for the various ...
Chemical composition of fine aerosol particles over the northern Chilean coastal waters was determined onboard the U.S. DOE G-1 aircraft during the VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) field campaign between October 16 and November 15, 2008. SO42-, NO3-, NH4+, and total organics (Org) were determined using an Aerodyne Aerosol Mass Spectrometer, and SO42-, NO3-, NH4+, Na+, Cl-, CH3SO3-, Mg2+, Ca2+, and K+ were determined using a particle-into-liquid sampler-ion chromatography technique. The results show the marine boundary layer (MBL) aerosol mass was dominated by non- sea-salt SO42- followed by Na+, Cl-, Org, NO3-, and NH4+, in decreasing importance; CH3SO3-, Ca2+, and K+ rarely exceeded their respective limits of detection. The SO42- aerosols were strongly acidic as the equivalent NH4+ to SO42- ratio was only ~0.25 on average. NaCl particles, presumably of sea-salt origin, showed chloride deficits but retained Cl- typically more than half the ...
The rate of the oxygen-exchange reaction in an aqueous solution of a heterocyclic oxygen compound, 2,4,6-trimethylpyrylium perchlorate, was quantitated. The /sup 18/O isotope effect in /sup 13/C NMR spectroscopy affords a direct, continuous, and relatively simple analysis of the reaction and was used to obtain data on the incorporation of /sup 18/O from solvent H/sub 2//sup 18/O into the pyrylium salt. Due to the low solubility of this salt in aqueous solutions, 2,4,6-trimethyl(2-/sup 13/C)pyrylium perchlorate and 2,4,6-trimethyl(2,6-/sup 13/C/sub 2/)pyrylium perchlorate were synthesized to facilitate the acquisition of the data on an NTC-200 spectrometer operating at 50.31 MHz. Upon incorporation of /sup 18/O into the pyrylium salt, the /sup 13/C NMR signal of the directly bonded carbon atom is shifted upfield 0.038 ppm. A /sup 13/C isotope effect is also detected in the doubly /sup 13/C-enriched pyrylium salt where the /sup 13/C NMR signal for /sup 13/C-O-/sup 13/C appears 0.011 ppm ...
The control problem associated to a class of horizontal-axis fixed-pitch variable-speed low-power wind energy conversion systems, working in the partial load region, consisting in the energy conversion maximization, is approached here under the assumption that the wind turbine model and its parameters are poorly known. Using a new approach derived from the optimum seeking methods category, generically called Maximum Power Point Tracking (MPPT), the proposed control solution aims at driving the average position of the operating point near to optimality. Instead of inducing sinusoidal search signals, the wind turbulence is here used as search disturbance. The high-speed shaft's average rotational speed is slowly adjusted using the Fast Fourier Transform processing of some available measures from the system as an estimate of the operating point's position/distance to optimality. Numerical simulations are used for preliminary checking the control law ...
In 1980 the multilevel multichannel R-matrix code SAMMY was released for use in analysis of neutron data at the Oak Ridge Electron Linear Accelerator. Since that time, SAMMY has undergone significant modifications: (1) User-friendly options have been incorporated to streamline common operations and to protect a run from common user errors, (2) The Reich-Moore formalism has been extended to include an optional logarithmic parameterization of the external R-matrix, for which any or all parameters may be varied, (3) the ability to vary sample thickness, effective temperature, matching radius, and/or resolution-broadening parameters has been incorporated, (4) to avoid loss of information (i.e. computer round-off errors) between runs, the ''covariance file'' now includes precise values for al variables, (5) Unused but correlated variables may be included in the analysis. Because of these and earlier changes, the 1980 SAMMY manual is now hopelessly ...
The nature of the hard X-ray source XSSJ12270-4859 is still unclear though it was claimed to be a magnetic Cataclysmic Variable. We here present a broad-band X-ray and gamma ray study based on a recent XMM-Newton observation and archival INTEGRAL and RXTE data. From the Fermi/LAT 1-year point source catalogue, we tentatively associate XSSJ12270-4859 with 1FGLJ1227.9-4852, a source of high energy gamma rays with emission up to 10GeV. We complement the study with UV photometry from XMM-Newton and ground-based optical and near-IR photometry. The X-ray emission is highly variable showing flares and intensity dips. The X-ray flares consist of flare-dip pairs. Flares are also detected in the UV range but not the dips. Aperiodic dipping behaviour is also observed during X-ray quiescence but not in the UV. The 0.2-100keV spectrum is featureless and described by a power law model with Gamma=1.7. The 100MeV-10GeV spectrum is instead represented by a ...
Extracting useful information from high-dimensional data is an important focus of today's statistical research and practice. Penalized loss function minimization has been shown to be effective for this task both theoretically and empirically. With the virtues of both regularization and sparsity, the $L_1$-penalized squared error minimization method Lasso has been popular in regression models and beyond. In this paper, we combine different norms including $L_1$ to form an intelligent penalty in order to add side information to the fitting of a regression or classification model to obtain reasonable estimates. Specifically, we introduce the Composite Absolute Penalties (CAP) family, which allows given grouping and hierarchical relationships between the predictors to be expressed. CAP penalties are built by defining groups and combining the properties of norm penalties at the across-group and within-group levels. Grouped selection occurs for nonoverlapping groups. Hierarchical ...
I review what we know about the donor stars in cataclysmic variables (CVs), focusing particularly on the close link between these binary components and the overall secular evolution of CVs. I begin with a brief overview of the "standard model" of CV evolution and explain why the key observables this model is designed to explain - the period gap and the period minimum -- are intimately connected to the properties of the secondary stars in these systems. CV donors are expected to be slightly inflated relative to isolated, equal-mass main-sequence (MS) stars, and this "donor bloating" has now been confirmed observationally. The empirical donor mass-radius relationship also shows a discontinuity at M_2 = 0.2 M_sun which neatly separates long- and short-period CVs. This is strong confirmation of the basic disrupted magnetic braking scenario for CV evolution. The empirical M_2-R_2 relation can be combined with stellar models to construct a complete, semi-empirical donor ...
We introduce a methodology for analysis of multiwavelength data from X-ray selected BL Lac (XBL) objects detected in the TeV regime. By assuming that the radio--through--X-ray flux from XBLs is nonthermal synchrotron radiation emitted by isotropically-distributed electrons in the randomly oriented magnetic field of a relativistic blazar jet, we obtain the electron spectrum. This spectrum is then used to deduce the synchrotron self-Compton (SSC) spectrum as a function of the Doppler factor, magnetic field, and variability timescale. The variability timescale is used to infer the comoving blob radius from light travel-time arguments, leaving only two parameters. With this approach, we accurately simulate the synchrotron and SSC spectrum of flaring XBLs in the Thomson through Klein-Nishina regimes. Photoabsorption by interactions with internal jet radiation and the intergalactic background light (IBL) is included. Doppler factors, magnetic fields, ...
We report results of the 2006 April multi-wavelengths campaign of SS 433, focusing on X-ray data observed with Suzaku at two orbital phases (in- and out-of- eclipse) and simultaneous optical spectroscopic observations. By analyzing the Fe25 K_alpha lines originating from the jets, we detect rapid variability of the Doppler shifts, dz/dt ~ 0.019/0.33 day^-1, which is larger than those expected from the precession and/or nodding motion. This phenomenon probably corresponding to "jitter" motions observed for the first time in X-rays, for which significant variability both in the jet angle and intrinsic speed is required. From the time lag of optical Doppler curves from those of X-rays, we estimate the distance of the optical jets from the base to be ~(3-4) \\times 10^14 cm. Based on the radiatively cooling jet model, we determine the innermost temperature of the jets to be T_0 = 13 +/- 2 keV and 16 +/- 3 keV (the average of the blue and red jets) ...
A stochastic-convective reactive (SCR) transport method is developed for one-dimensional steady transport in physically heterogeneous media with nonlinear degradation. The method is free of perturbation amplitude limitations and circumvents the difficulty of scale dependence of phenomenological parameters by avoiding volume-averaged specifications of diffusive/dispersive fluxes. The transport system is conceptualized as an ensemble of independent convective-reactive streamlines, each characterized by a randomized convective velocity (or travel time). Dispersive effects are treated as a component of the randomness in the streamline velocity ensemble, so no explicit expression for hydrodynamic dispersive flux is written in the streamline transport equation. The expected value of the transport over the stream tube ensemble is obtained as an average of solutions to the reactive convection equation according to the stream tube (travel time) probability distribution function. In this way, ...
This dissertation reports on the application of numerical optimization techniques as applied to fuel cell simulation and design. Due to the "multi-physics" inherent in a fuel cell, which results in a highly coupled and non-linear behavior, an experimental program to analyze and improve the performance of fuel cells is extremely difficult. This program applies new optimization techniques with computational methods from the field of aerospace engineering to the fuel cell design problem. After an overview of fuel cell history, importance, and classification, a mathematical model of solid oxide fuel cells (SOFC) is presented. The governing equations are discretized and solved with computational fluid dynamics (CFD) techniques including unstructured meshes, non-linear solution methods, numerical derivatives with complex variables, and sensitivity analysis with adjoint methods. Following the validation of the fuel cell model in 2-D and 3-D, the results of the sensitivity ...
Consideration of the technical feasibility of Yucca Mountain in Nevada as the site for a high-level nuclear waste repository has led to an intense debate regarding the economic, social, and political impacts of the repository. Impediments to the siting process mean that the nuclear waste problem is being resolved by adhering to the status quo, in which nuclear waste is stored at scattered sites near major population centers. To assess the merits of alternative siting strategies--including both the permanent repository and the status quo- we consider the variables that would be included in a model designed to select (1) the optimal number of disposal facilities, (2) the types of facilities (e.g., permanent repository or monitored retrievable facility), and (3) the geographic location of storage sites. The objective function in the model is an all-inclusive measure of social cost. The intent of the exercise is not to demonstrate the superiority of any single disposal ...
The main objectives were to evaluate efficacy and acceptability of a developmentally sensitive cognitive behavioral therapy for anxiety-based school refusal in adolescence. Twenty school-refusing adolescents meeting DSM-IV anxiety disorder criteria participated in a non-randomized trial, together with parents and school staff. Outcome was assessed at post-treatment and 2-month follow-up. Treated adolescents showed significant and maintained improvements across primary outcome variables (school attendance; school-related fear; anxiety), with medium to large effect sizes. Half of the adolescents were free of any anxiety disorder at follow-up. Additional improvements were observed across secondary outcome variables (depression; overall functioning; adolescent and parent self-efficacy). The treatment was rated as acceptable by adolescents, parents, and school staff, which may help explain the very low attrition rate. Social anxiety disorder was the ...
SYVAC3 (Systems Variability Analysis Code, generation 3) is a computer program that implements a method called systems variability analysis to analyze the behaviour of a system in the presence of uncertainty. This method is based on simulating the system many times to determine the variation in behaviour it can exhibit. SYVAC3 specializes in systems representing the transport of contaminants, and has several features to simplify the modelling of such systems. It provides a general tool for estimating environmental impacts from the dispersal of contaminants. This report describes the use and structure of SYVAC3. It is intended for modellers, programmers, operators and reviewers who deal with simulation codes based on SYVAC3. From this manual they can learn how to link a model with SYVAC3, how to set up an input file, and how to extract results from output files. The manual lists the subroutines of SYVAC3 that are available for use by models, and ...
We present the results of a monitoring campaign aimed at deriving rotation periods for a representative sample of stars in the young (30 Myr) open cluster IC 2602. Rotation periods were derived for 29 of 33 stars monitored. The periods derived range from 0.2d (one of the shortest known rotation periods of any single open cluster star) to about 10d (which is almost twice as long as the longest period previously known for a cluster of this age). We are able to confirm 8 previously known periods and derive 21 new ones, delineating the long period end of the distribution. Despite our sensitivity to longer periods, we do not detect any variables with periods longer than about 10d. The combination of these data with those for IC 2391, an almost identical cluster, leads to the following conclusions: 1) The fast rotators in a 30 Myr cluster are distributed across the entire 0.5 < B-V < 1.6 color range. 2) 6 stars in our sample are slow rotators, with periods longer ...
Being able to distinguish light-quark jets from gluon jets on an event-by-event basis could significantly enhance the reach for many new physics searches at the Large Hadron Collider. Through an exhaustive search of existing and novel jet substructure observables, we find that a multivariate approach can filter out over 95% of the gluon jets while keeping more than half of the light-quark jets. Moreover, a combination of two simple variables, the charge track multiplicity and the pT-weighted linear radial moment (girth), can achieve similar results. While this pair appears very promising, our study is only Monte Carlo based, and other discriminants may work better with real data in a realistic experimental environment. To that end, we explore many other observables constructed using different jet sizes and parameters, and highlight those that deserve further theoretical and experimental scrutiny. Additional information, including distributions of around 10,000 ...
Very recently we have assisted to a new development of quantum information, the so-called continuous variable (CV) quantum information theory. Such a further development has been mainly due to the experimental and theoretical advantages offered by CV systems, i.e., quantum systems described by a set of observables, like position and momentum, which have a continuous spectrum of eigenvalues. According to this novel trend, quantum information protocols like quantum teleportation have been suitably extended to the CV framework. Here, we briefly review some mathematical tools relative to CV systems and we consequently develop the concepts of quantum entanglement and teleportation in the CV framework, by analogy with the qubit-based approach. Some connections between teleportation fidelity and entanglement properties of the underlying quantum channel are inspected. Next, we face the study of CV quantum teleportation networks where more users share a multipartite state ...
Proactive qualification is today an integral part of the development process for steam turbines used in steam and combined cycle power plants. By providing experimentally based `random` variables, such as the steam path efficiency and blading reliability, it makes a valuable contribution to the economic `random` variables of the power plant, e.g. the rate of return, as viewed by the customer. One of the areas in which proactive product and process qualification plays an important role is the development of LP steam paths. (orig.) [Deutsch] Die proaktive Qualifikation ist heute fester Bestandteil des Entwicklungsprozesses bei Dampfturbinen, die fuer den Einsatz in Dampf- und Kombikraftwerken bestimmt sind. Sie leistet mit Hilfe experimentell ermittelter `Zufalls`-Variablen, wie z.B. Wirkungsgrad der Fluten und Zuverlaessigkeit der Beschaufelungen, einen wertvollen Beitrag zu den fuer die Kunden wichtigen wirtschaftlichen `Zufalls`-Variablen des ...
A mixture of crushed rock and bentonite is being considered as backfill and sealant for high-level nuclear waste repositories. Many variables affect the hydraulic conductivity of such a mixture, including the size and shape of the rock particles, method of mixing, water content and density of the clay, and the weight ratio of rock to clay. Mixtures of crushed basalt and bentonite have been tested to determine the relative effects of these variables. Two types of permeameters are used, 20 cm diameter stainless steel permeameters and 10 cm diameter clear PVC permeameters. Plugs are installed as a single lift or in many lifts; the water content of the clay ranged from air-dry (in most cases) to as high as 200%. Preliminary results show that a mixture of 75% crushed basalt and 25% bentonite has a hydraulic conductivity between 1 x 10/sup -9/ cm/s and 2.5 x 10/sup -8/ cm/s. In some cases, preferential flow paths have developed (possibly as a result ...
A butterfly valve is a type of flow control device, typically used to regulate a fluid flowing. Currently, FEA is often used to predict the safety in the design of valve disc. Also, the study about the affection of butterfly valve's disc to the valve flow characteristics by using CFD has been done by many researchers. Along with the development of computer technique, design and analysis of computer experiments has becoming more and more important in engineering design and optimization. Hereinto Kriging model is one popular analysis approach for the purpose of creating a cheap ``meta-model'' as a surrogate to a computationally expensive simulation model. In this paper, the numerical analysis considered the strength, pressure loss coefficient and weight of valve disc simultaneously is investigated to improve the shape of a traditional butterfly valve disc. Firstly, an initial model of butterfly valve is made to evaluate the performance of the valve disc by using CFD and FEM. Then several ...
This presentation concerns our continued research on adjoint--based optimization of viscous incompressible flows (the Navier--Stokes problem) coupled with heat conduction involving change of phase (the Stefan problem), and occurring in domains with variable boundaries. This problem is motivated by optimization of advanced welding techniques used in automotive manufacturing, where the goal is to determine an optimal heat input, so as to obtain a desired shape of the weld pool surface upon solidification. We argue that computation of sensitivities (gradients) in such free--boundary problems requires the use of the shape--differential calculus as a key ingredient. We also show that, with such tools available, the computational solution of the direct and inverse (optimization) problems can in fact be achieved in a similar manner and in a comparable computational time. Our presentation will address certain mathematical and computational aspects of the method. As an ...
The effects of 0.2 and 0.5 mL/kg Innovar (a neuroleptic analgesic) on cardiovascular functions and reflexes in rabbits were measured. We recorded the effects of Innovar on arterial pressure, heart rate, respiration rate, ventricular contractility, arterial oxygen tension, as well as the drug's effects on the bradycardia and vasoconstrictor response to cigarette smoke stimulation of the nose (the so-called "nasopharyngeal reflex"). In animals given 0.2 mL/kg Innovar, all steady state cardiovascular variables had returned to pre-Innovar levels in 45 min, as had the efficacy of the nasopharyngeal reflex. In animals given 0.5 mL/kg Innovar, all steady state cardiovascular variables, except PaO2, were slightly but significantly depressed for up to 135 min after injection. The nasopharyngeal reflex returned to normal within 90 min. Because of the calmative and analgesic effects of Innovar, and its only moderate effects on cardiovascular functions and ...
The scalar mixing time scale, a key quantity in many turbulent combustion models, is investigated for reactive scalars in premixed combustion. Direct numerical simulations (DNS) of three-dimensional, turbulent Bunsen flames with reduced methane-air chemistry have been analyzed in the thin reaction zones regime. Previous conclusions from single step chemistry DNS studies are confirmed regarding the role of dilatation and turbulence-chemistry interactions on the progress variable dissipation rate. Compared to the progress variable, the mixing rates of intermediate species is found to be several times greater. The variation of species mixing rates are explained with reference to the structure of one-dimensional premixed laminar flames. According to this analysis, mixing rates are governed by the strong gradients which are imposed by flamelet structures at high Damkoehler numbers. This suggests a modeling approach to estimate the mixing rate of ...
Glacier fluctuations exclusively due to internal variations in the climate system are simulated using downscaled integrations of the ECHAM4/OPYC coupled general circulation model (GCM). A process-based modeling approach using a mass balance model of intermediate complexity and a dynamic ice flow model considering simple shearing flow and sliding are applied. Multi-millennia records of glacier length fluctuations for Nigardsbreen (Norway) and Rhonegletscher (Switzerland) are simulated using auto-regressive processes determined by statistically downscaled GCM experiments. Return periods and probabilities of specific glacier length changes using GCM integrations excluding external forcings such as solar irradiation changes, volcanic or anthropogenic effects are analyzed and compared to historical glacier length records. Preindustrial fluctuations of the glaciers as far as observed or reconstructed, including their advance during the ''Little Ice Age'', ...
Staggered arrays of dimples printed on opposite surfaces of a cooling channel is formulated numerically and optimized with hybrid multi-objective evolutionary algorithm and Pareto optimal front. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing, and dimple depth, to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-means clustering technique and some of the clustered points were evaluated ...
Staggered arrays of dimples printed on opposite surfaces of a cooling channel is formulated numerically and optimized with hybrid multi-objective evolutionary algorithm and Pareto optimal front. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing, and dimple depth, to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-means clustering technique and some of the clustered points were evaluated ...
We discuss strictly efficient models for measurement-based quantum computing using physical continuous variables, such as field modes of light. Such measurement-based quantum computing (MBQC) provides a promising paradigm for quantum computation as it does not require performing unitary gates during the computation, but rather appropriate readout. Here, we introduce novel schemes for which the resource state can be reasonably and efficiently prepared, and which notably do not require having infinite squeezing or mean energy available. What is more, error correction techniques are implementable, as the logical information is stored in finite-dimensional objects grasping correlations of the quantum states. Using the ideas of computational tensor networks we discuss how to sequentially prepare suitable physical resource states with cavity QED or with non-linear optics and how to efficiently implement a computational universal set of quantum operations with feasible ...
This report introduces a microprocessor system composed of a Z-80 single-board computer controlling a gas-carburizing process. The system has 7 analogical input and output signals 24 switch signal-input and 12 switch signal-output signals, which are applicable for temperature, carbon potential, and mechanical-movement control of multipurpose sealed furnaces, or for mutiple-zone temperature, carbon potential, and mechanical-movement control of continuous gas carburizing furnaces; or for distributed control of pit-type carburizing furnaces. The setpoints of variables, such as treating time, temperature, carbon potential of carburizing period, carbon potential of diffusion period, depth of carburizing layer, P.I.D. etc., are entered by keyboard and stored into memories, and actual values are displayed by digital tubes. Furthermore, the fault of thermocouple, oxygen probe, or infrared CO/sub 2/ analyzer; carbon potential, or temperature exceeding the setting value; ...
The quasar B2005+403 located behind the Cygnus region, is a suitable object for studying the interplay between propagation effects, which are extrinsic to the source and source intrinsic variability. On the basis of VLBI experiments performed at 1.6, 5, 8, 15, 22, and 43GHz between 1992-2003 and parallel multi-frequency monitoring of the total flux density, we investigated the variability of total flux density and source structure. Below 8 GHz, the point-like VLBI source is affected by scatter-broadening of the turbulent interstellar medium, which is located along the line of sight and likely associated with the Cygnus region. We present and discuss the measured frequency dependence of the source size, which shows a power-law with slope of -1.91+/-0.05. From the measured scattering angle at 1GHz of 77.1+/-4.0mas a SM=0.43+/-0.04 m^{-20/3} kpc is derived, consistent with the general properties of the ISM in this direction. The decreasing effect ...
In models with dynamical electroweak symmetry breaking, this breaking is normally communicated to quarks and leptons by a set of vector bosons with masses generated via sequential breaking of a larger gauge symmetry. In reasonably ultraviolet-complete theories of this type, the number of stages of breaking of the larger gauge symmetry is usually equal to the observed number of quark and lepton generations, $N_{gen.}=3$. Here we investigate the general question of how the construction and properties of these models depend on $N_{gen.}$, regarded as a variable. We build and analyze models with illustrative values of $N_{gen.}$ different from 3 (namely, $N_{gen.}=1,2,4$) that exhibit the necessary sequential symmetry breaking down to a strongly coupled sector that dynamically breaks electroweak symmetry. Our results for variable $N_{gen.}$ show that one can robustly obtain, for this latter sector, a theory with a gauge coupling that is large but ...
A central issue to be addressed within the Nevada Nuclear Waste Storage Investigations (NNWSI) is the role which fractures will play as the variably saturated, fractured rock mass surrounding the waste package responds to heating, cooling, and episodic infiltration events. Understanding the role of fractures during such events will, in part, depend on our ability to make geophysical measurements of perturbations in the moisture distribution in the vicinity of fractures. In this study we first examine the details of the perturbation in the moisture distribution in and around a fracture subjected to an episodic infiltration event, and then integrate that behavior over the scale at which moisture measurements are likely to be made during the Engineered Barrier Design Test of the NNWSI project. To model this system we use the TOUGH hydrothermal code and fracture and matrix properties considered relevant to the welded ash flow tuff found in the Topopah Spring member at ...
The genetically significant dose (GSD) is an index variable which exclusively allows to describe the genetic risk in the progeny of a population due to the application of ionizing radiation and radioactive substances in one part of this population. It may result in wrong interpretation of population exposure at increasing incidence of examinations in a population involving ionizing radiation and radioactive drugs at simultaneously increasing application of alternative methods in children and adolescents owing to the fact that it indicates a downward trend although somatic exposure of this population has increased. Therefore, it is recommended to state both the GSD and the level of somatic radiation exposure of the population taken from the individual sources for the comparison and assessment of radiation exposure from various sources in future. Although the somatically significant dose constitutes the suitable variable complementary to GSD in ...
The unit cost of energy production of wind generators is examined by means of a model of the turbine power curve and the Weibull model of wind probability function, by applying the usual economic equations. The analysis is carried out in terms of dimensionless variables whose range of variability is defined by examining the data of 80 modern commercial wind turbines; likewise, the economic parameters are based on the present state of costs. The unit cost decreases asymptotically when alpha (ratio between mean wind speed and cut-in speed) - increases and shows a lower limit of 2 to 5 Ecent/kWh. This cost depends both on the value of the machine parameter {phi} (ratio between nominal and cut-in speed) and on the basic prices. The effect of the Weibull shape parameter kappa is different according to the values of {alpha} and {phi}: with low {alpha} and high {phi} the unit cost increases along with {kappa} (that is with the regularity of the ...
The dynamical factors controlling the mean state and variability of the east Pacific intertropical convergence zone (ITCZ) and the associated cross-equatorial boundary layer flow are investigated using observations from the East Pacific Investigation of Climate (EPIC2001) project. The tropical east Pacific exhibits a southerly boundary layer flow that terminates in the ITCZ. This flow is induced by the strong meridional sea surface temperature (SST) gradient in the region. Away from the equator and from deep convection, it is reasonably well described on a day-to-day basis by an extended Ekman balance model. Variability in the strength and northward extent of this flow is caused by variations in free-tropospheric pressure gradients that either reinforce or oppose the pressure gradient associated with the SST gradient. These free-tropospheric gradients are caused by easterly waves, tropical cyclones, and the Madden Julian oscillation.Convergence ...
Various phenomenological theories of wave-type heat transport, which can be interpreted as the models of an isotropic rigid heat conductor with an internal vector state variable, have been proposed in the literature with the objective to describe the second sound propagation in dielectric crystals. The aim of this paper is to analyze the relation between these phenomenological approaches and the phonon gas hydrodynamics. The four-moment phonon gas hydrodynamics based on the maximum entropy closure of the moment equations with nonlinear isotropic phonon dispersion relation is considered for this purpose. We reformulate the equations of this hydrodynamics in terms of energy and quasi-momentum as the primitive fields and subsequently demonstrate that, from the macroscopic point of view, they can be understood as describing the reference model of an isotropic rigid heat conductor with quasi-momentum playing the role of the internal vector state ...
This paper presents the Cheng cycle system featured by variable heating/generation ratio for effective operation of cogeneration systems (CGS). In this system, a superheater and reheating burner are added to an exhaust heat recovery (EHR) boiler for conventional gas turbine CGSs, while additional injection steam piping is attached to a gas turbine. Steam is injected through manifolds mounted on the periphery of a combustion chamber, and hot gas mixture of steam and air in a combustion chamber is expanded in a turbine and converted to motive power. This technology thus can improve efficiency and output power, and can operate variably CGSs corresponding to heating and generation demands. This technology has been promoted by introducing the technology of middle class Cheng cycle CGS with 4MW class gas turbine from IPT Co., U.S.A. The first system of 6400 kW is now under production for start of operation in 1996. Its EHR boiler is featured by ...
We have used HST/FOS to study faint UV stars in the core of the nearby globular cluster NGC 6397. We confirm the presence of a 4th cataclysmic variable (CV) in NGC 6397 (CV 4), and we use the photometry of Cool et al. (1998) to present evidence that CVs 1--4 all have faint disks and probably low accretion rates. By combining these results with new UV spectra of CV 1 and the published spectra of Grindlay et al. (1995) we present new evidence that CVs 1--3 may be DQ Her systems, and we show that CV 4 may either be a dwarf nova or another magnetic system. Another possibility is that the CVs could be old novae in hibernation between nova eruptions. We also present the first spectrum of a member of a new class of UV bright stars in NGC 6397. These faint, hot stars do not vary, unlike the CVs, and are thus denoted as ``non-flickerers'' (NFs). Like the CVs, their spatial concentration is strongly concentrated toward the cluster center. Using stellar atmosphere models we ...
The carbon dioxide concentration has been measured in air samples collected approximately once per week at 22 globally distributed sites during 1981-1984. All samples were analyzed on the same non-dispersive infrared analyzer apparatus. The measured concentrations are directly traceable to the WMO primary CO/sub 2/ standards. Samples which do not contain well-mixed, regionally representative air or which have been contaminated during or subsequent to sampling, have been identified. The selected data have been analyzed using an objective curve fitting method which enables improved estimation of uncertainties associated with derived parameters. The latitudinal distribution of annual mean CO/sub 2/ concentration at the network sites shows significant interannual variability possibly related to the 1982-1983 El NinoSouthern Oscillation event. No evidence was found for significant interannnual variations or trend in the phase or amplitude of the seasonal cycle. ...
The application of neural networks, alone or in conjunction with other advanced technologies (expert systems, fuzzy logic, and/or genetic algorithms), to some of the problems of complex engineering systems has the potential to enhance the safety, reliability, and operability of these systems. Typically, the measured variables from the systems are analog variables that must be sampled and normalized to expected peak values before they are introduced into neural networks. Often data must be processed to put it into a form more acceptable to the neural network (e.g., a fast Fourier transformation of the time-series data to produce a spectral plot of the data). Specific applications described include: (1) Diagnostics: State of the Plant (2) Hybrid System for Transient Identification, (3) Sensor Validation, (4) Plant-Wide Monitoring, (5) Monitoring of Performance and Efficiency, and (6) Analysis of Vibrations. Although specific examples described ...
The application of neural networks, alone or in conjunction with other advanced technologies (expert systems, fuzzy logic, and/or genetic algorithms), to some of the problems of complex engineering systems has the potential to enhance the safety, reliability, and operability of these systems. Typically, the measured variables from the systems are analog variables that must be sampled and normalized to expected peak values before they are introduced into neural networks. Often data must be processed to put it into a form more acceptable to the neural network (e.g., a fast Fourier transformation of the time-series data to produce a spectral plot of the data). Specific applications described include: (1) Diagnostics: State of the Plant (2) Hybrid System for Transient Identification, (3) Sensor Validation, (4) Plant-Wide Monitoring, (5) Monitoring of Performance and Efficiency, and (6) Analysis of Vibrations. Although specific examples described ...
This report is the conclusion of a three-part series that describes and attempts to explain regional coal quality variations within the foothills/mountains region of Alberta. Proximate and ultimate analysis variables, plus some vitrinite reflectance and maceral analyses, are examined for the Jurassic-Lower Cretaceous Kootenay Group, Lower Cretaceous Luscar Group, the Lower Paleocene Coalspur Formation, and the Upper Paleocene Obed-Marsh coal-bearing units. The study has two major components: a statistical analysis and mapping of coal quality data provided by the Energy Resources Conservation Board; and a 'geologic models' section, in which regional and local in-seam coal quality variations are examined from a geological perspective. The first component is designed to describe, characterize, and set limits for the coal quality variables, while the second component should provide from a geological perspective, insight as to why ...
This paper describes the derivation of a new equation that can be used to model the permeability behavior of a fractured, sorptive-elastic media, such as coal, under variable stress conditions commonly used during measurement of permeability data in the laboratory. The model is derived for cubic geometry under biaxial or hydrostatic confining pressures. The model is also designed to handle changes in permeability caused by adsorption and desorption of gases from the matrix blocks. The model equations can be used to calculate permeability changes caused by the production of methane from coal as well as the injection of gases, such as carbon dioxide, for sequestration in coal. Sensitivity analysis of the model found that each of the input variables can have a significant impact on the outcome of the permeability forecast as a function of changing pore pressure; thus, accurate input data are essential. The permeability model can also be used as a ...
The Convective and Orographically-induced Precipitation Study (COPS) has the aim to advance the quality of forecasts of orographically-induced precipitation in complex terrain. COPS is a Research and Development Project of the World Weather Research Program and considered to be one of the largest field campaigns on quantitative precipitation forecasting that has been performed so far. A network of state-of-the-art active and passive remote sensing systems was combined with in total 10 airborne platforms, Meteosat rapid scans and dense networks of standard meteorological instruments during the three months long field phase (June-August, 2007) in south-western Germany/eastern France to observe atmospheric variables in the three spatial dimensions and in time. By the University of Hohenheim, two novel ground-based mobile scanning lidar systems were deployed: a scanning rotational Raman lidar which provides combined measurements of the field of atmospheric temperature ...
The properties of the mixing layer in dynamic systems were studied by the example of a mathematical model of the cubic image type. Its role in the generation of information and the evolution of its significance was shown. At the moment of generation, information is of zero significance, and this significance then increases. A criterion of efficiency was proposed, and the optimum moment of making a decision in creative work was determined. It was shown that the increase in the variability of the parameters of a living system upon entry into the mixing layer and its decrease upon exit can serve as objective indicators of the transition of the system from one dynamic regime (attractor) to another. PMID:12723364
The desirable performance attributes of a vertical axis wind turbine (VAWT) include high starting torque, high peak efficiency, broad operating range and a reasonable insensitivity to the parameters that define its operation. The theoretical performance of three variable pitch mechanisms for VAWT are compared. Cycloturbines use cam devices or gears to impose a sinusoidal pitch regime. In the mass-stabilised system, pitch is determined by the interplay of two opposing moments on the blades. These two mechanisms are compared with Aeropitch, a hypothetical pitch control system in which stabilising moments are related to the blade relative velocity. (Author)
A new approach for the selection of best PSS locations in multimachine power systems is proposed in this paper. Study shows that the right-eigenvector measures the activity of state variables and the left-eigenvector measures the control effect of control signals. Based on the right and left eigenvector the concept of sensitivity of PSS effect (SPE) is presented and used to identify the best PSS locations. The proposed method is used to identify the best PSS location in a 13-machine system to increase the damping of an interarea mode. The time-domain simulation results confirm that the prediction of best PSS location by SPE method is correct and accurate.
The structure functions (SF) of nuclei determined within the framework of the flucton model with rescaling (FMR) are compared with new experimental data of the ITEP on cumulative #pi#-meson yield in a wide range of the scale variable X (1
Using some modification of the standard fermion technique we derive factorized formula for spin operator matrix elements (form-factors) between general eigenstates of the Hamiltonian of quantum Ising chain in a transverse field of finite length. The derivation is based on the approach recently used to derive factorized formula for Z_N-spin operator matrix elements between ground eigenstates of the Hamiltonian of the Z_N-symmetric superintegrable chiral Potts quantum chain. The obtained factorized formulas for the matrix elements of Ising chain coincide with the corresponding expressions obtained by the Separation of Variables Method.
Sixty-seven unresolved objects with flat blue spectra that had no apparent features on the plates of the Case Low-Dispersion Northern Sky Survey have been observed at higher dispersion and to shorter wavelengths in order to determine their nature. The following classifications are proposed: 20 low-redshift QSOs (z greater than 1.7), two Seyfert 2 galaxies, 23 stars, and two variable objects. The spectra obtained for the remaining 20 objects were flat with no obvious features, but noisy, and these will need further observation. 5 references.
The role of natural enemies in the regulation of populations is one of the major questions facing population ecologists. Simplification have led to two theoretical ways of incorporating the role of natural enemies in single ecological models: diffusion models and patch-type models. The predictions of the models are different because of the way variability is incorporated. Three equations are presented for diffusion models and one for patch models. Since the two types of models apply at different combinations of spatial and temporal scales, the right model(s) to choose for a particular study requires careful assessment. A continuing dialogue between experimentalists and theoreticians will lead to a better understanding of natural systems such as those that occur in biological control.
Twenty years after its building, the tertiary sector of La Defense district near Paris has been rehabilitated. The main reason is not only the age and wear of materials but the heating costs, the fire protection regulations, the search for a better air quality and air renewing with less dusts, smells and noise and a controlled moisture. This paper describes first the original installation of the Monge CB 6 office building and then the renovated installation: the central hot and cold air-treatment plant, the variable flow ventilation system, the air extraction and supply system threw the roofs and the pressure and thermal regulation of the installation. (J.S.)
The activities of the radiochemical section (part of the Analytical Chemistry Group) deal mostly with problems of composition. Activation analysis with thermal neutrons serves for most of the trace element analyses either with or without chemical separations. Ge(Li) spectrometry has been increasingly automated so that many analyses can now be performed by relatively unskilled personnel. In a number of analyses an A.V.F.-cyclotron was employed: such an accelerator can deliver not only different types of charged particles at variable energies but also fast neutrons. (T.G.).
An electronic computer circuit is described for producing an output voltage proportional to the product or quotient of tbe voltages of a pair of input signals. ln essence, the disclosed invention provides a computer having two channels adapted to receive separate input signals and each having amplifiers with like fixed amplification factors and like negatlve feedback amplifiers. One of the channels receives a constant signal for comparison purposes, whereby a difference signal is produced to control the amplification factors of the variable feedback amplifiers. The output of the other channel is thereby proportional to the product or quotient of input signals depending upon the relation of input to fixed signals in the first mentioned channel.
The real-time polymerase chain reaction (PCR) quantification of several vaginal bacterial groups in healthy women and patients developing asymptomatic bacterial vaginosis (BV) and candidiasis (CA) was performed. Statistical analysis revealed that the BV condition is characterised by a great variability among subjects and that it is associated with a significant increase of Prevotella, Atopobium, Veillonella and Gardnerella vaginalis, and a drop in Lactobacillus. On the contrary, the vaginal microflora of healthy women and patients developing CA was found to be homogeneous and stable over time. PMID:18762999
The real-time polymerase chain reaction (PCR) quantification of several vaginal bacterial groups in healthy women and patients developing asymptomatic bacterial vaginosis (BV) and candidiasis (CA) was performed. Statistical analysis revealed that the BV condition is characterised by a great variability among subjects and that it is associated with a significant increase of Prevotella, Atopobium, Veillonella and Gardnerella vaginalis, and a drop in Lactobacillus. On the contrary, the vaginal microflora of healthy women and patients developing CA was found to be homogeneous and stable over time.
Advances in the development of several electrooptic shutter devices utilizing the quadratic electrooptic effect of lead lanthanum zirconate titanate (PLZT) ceramic wafers are described. Aperture sizes utilized in these PLZT devices ranged from 25 ..mu..m to 0.25 m. Practical applications of the shutters discussed in this paper include eye protection in military and industrial applications, a goggle-type device with dual synchronously operated PLZT shutters for use in a stereoscopic three-dimensional TV display, an electrically controlled variable density filter for use with vidicon tubes, a large-aperture photographic shutter for image motion compensation cameras, and a page composer for use in a holographic memory system.
The removal of Reactive Black 5 dye in an aqueous solution by electrocoagulation (EC) as well as addition of flocculant was investigated. The effect of operational parameters, i.e. current density, treatment time, solution conductivity and polymer dosage, was investigated. Two models, namely the artificial neural network (ANN) and the response surface method (RSM), were used to model the effect of independent variables on percentage of dye removal. The findings of this work showed that current density, treatment time and dosage of polymer had the most significant effect on percentage of dye removal (p0.8). PMID:21411950
In this paper, it is suggested that the selection method of optimal parameter of power system stabilizer (PSS) with robustness in low frequency oscillation for power system using real variable elitism genetic algorithm (RVEGA). The optimal parameters were selected in the case of power system stabilizer with one lead compensator, and two lead compensator. Also, the frequency responses characteristics of PSS, the system eigenvalues criterion and the dynamic characteristics were considered in the normal load and the heavy load, which proved usefulness of RVEGA compare with Yu's compensator design theory. (author). 20 refs., 15 figs., 8 tabs.
Using disaggregated data from the Brazilian stock market, we calculate default probabilities for 30 different economic sectors. Empirical results suggest that domestic macroeconomic factors can explain these default probabilities. In addition, we construct the Minimum Spanning Tree (MST) and the ultrametric hierarchical tree with the MST based on default probabilities to disclose common trends, which reveals that some sectors form clusters. The results of this paper imply that macroeconomic variables have distinct effects on default probabilities, which is important to take into account in credit risk modeling and the generation of stress test scenarios.
Capsulation of terbium(III) chloride in porous glass in the amount of 1.5-150 #mu#mole g"-"1 was carried out by impregnation of the glass substrate with variable concentrations of the salt aqueous solutions. Maximum luminosity of terbium(III) chloride in porous glass is found at its concentration of 120 #mu#mole g"-"1, that is close to the corresponding monolayer surface filling. Concentration dependences of terbium(III) luminescence and its quenching by adsorbed water are in agreement with the ideas of molecular fragmentation and uniform distribution of capsulated salt on the substrate surface
Although the majority of men presenting with non-seminomatous germ cell tumours (NSGCT) are cured, late relapse (occurring more than 2 years after obtaining a complete response to treatment) is increasingly recognized. The typical patterns of disease spread have been well-documented, but the findings at late relapse are more variable and less well-described. We discuss the phenomenon of late relapse, the characteristics of teratoma differentiated (TD), and the issue of long-term imaging surveillance of patients with NSGCT. The potential sites of late relapse of NSGCT and the associated spectrum of imaging appearances are illustrated.
Although the majority of men presenting with non-seminomatous germ cell tumours (NSGCT) are cured, late relapse (occurring more than 2 years after obtaining a complete response to treatment) is increasingly recognized. The typical patterns of disease spread have been well-documented, but the findings at late relapse are more variable and less well-described. We discuss the phenomenon of late relapse, the characteristics of teratoma differentiated (TD), and the issue of long-term imaging surveillance of patients with NSGCT. The potential sites of late relapse of NSGCT and the associated spectrum of imaging appearances are illustrated.
A calculation on the stabilization of the sideband instability in the free electron laser (FEL) and inverse FEL (IFEL) was completed. The issue arises in connection with the use of a tapered (''variable-parameter'') undulator of extended length, such as might be used in an ''enhanced efficiency'' traveling-wave FEL or an IFEL accelerator. In addition, the FEL facility at Columbia was configured as a traveling wave amplifier for a 10-kW signal from a 24-GHz magnetron. The space charge field in the bunches of the FEL was measured. Completed work has been published.
The paper describes an application of the tree classification method Random Forest (RF), as used in the analysis of data from the ground-based gamma telescope MAGIC. In such telescopes, cosmic gamma-rays are observed and have to be discriminated against a dominating background of hadronic cosmic-ray particles. We describe the application of RF for this gamma/hadron separation. The RF method often shows superior performance in comparison with traditional semi-empirical techniques. Critical issues of the method and its implementation are discussed. An application of the RF method for estimation of a continuous parameter from related variables, rather than discrete classes, is also discussed.
Directionally solidified nickel-based superalloy DZ4 is an important structural material. However, the grinding burn occurs in grinding processes has hindered the grinding efficiency and dimensional accuracy. This paper investigates the grinding mechanism of this new type of superalloy based on the systematical analyses of variable characteristics of the grinding force, grinding temperature, topography of ground surface, hardness distribution of surface layer, as well as morphology of surface layer from a metallographical point of view. The results will be beneficial to grinding the superalloy with high efficiency and high precision. (orig.)
Analysis of data on seedling traits from 20 diverse genotypes revealed significant differences fro most of the seedling traits. Significant estimates of broad-sense heritability were observed for VI, ERI, FRTW, DRTW and R/S ratio. Genetic advance was maximum for VI,ERI and E%. The correlation of VI with ERI and R/S ratio was negative and significant, whereas it was positive and significant with E%, FSHW and DSHW. Characterization of the sorghum genotypes according to Anderson's Metro glyph Statistics revealed five different groups for seedling trails. (authors)
Rats and guinea pigs were fed "2"3"8Pu either biologically incorporated into alfalfa (by growth of the plant on soil containing Pu) or added as a solution to alfalfa, or were gavaged with a Pu solution. Depending upon the plant material fed, there appeared to be a twofold increase in "2"3"8Pu-gut absorption by the rat and a two- to fourfold increase in the guinea pig as compared with absorption from the Pu solution. The data, though limited and variable, suggest that Pu bound to plant tissue may have higher gut absorptivity than inorganic Pu in both herbivorous and nonherbivorous rodents.
A classical linear group GJ between the graded ring S= d=0^~Sd, where Sd is the character group of the symmetric group Sd, and the inverse limit J with respect to n of rings of symmetric polynomials in n variables. As a consequence, we complete the description of relations between generators for O(n)-invariants as well as the description of relations for invariants of mixed representations of quivers. We also obtain an independent proof of the result that the ideal of free relations for GL(n)-invariants is zero, which was proved by Donkin in [S. Donkin, Invariant functions on matrices, Math. Proc. Cambridge Philos. Soc. 113 (1993) 23-43].
We describe dimensionally constrained symbolic regression which has been developed for mass measurement in certain classes of events in high-energy physics (HEP). With symbolic regression, we can derive equations that are well known in HEP. However, in problems with large number of variables, we find that by constraining the terms allowed in the symbolic regression, convergence behavior is improved. Dimensionally constrained symbolic regression (DCSR) finds solutions with much better fitness than is normally possible with symbolic regression. In some cases, novel solutions are found.
With the help of heat balance equation and high temperature thermodynamic function, the calibration relation of jet temperature with discharge power, gas flow rate was obtained for nitrogen thermal plasma. It was shown that the results were agreed with the principle of similarity. The jet temperature was a function of Peff/f, instead of a general two variables function of Peff and f, which were effective discharge power and working gas flow rate, respectively. A related discussion has been given; it will be referable to thermal plasma applications. (authors)
The effect of pair-binding energy variations on the denaturation of double stranded DNAs is investigated. Using a two-parameter renormalization group (RG) analysis and extensive transfer matrix calculations, we find a random quenched-in variations to be marginally irrelevant, indicating that the system is self-averaging at the transition. The effect of a recently-proposed variable backbone stiffness is also investigated. Although irrelevant in the RG sense, it dramatically amplifies the randomness, leading to the appearance of ``multi-step melting'' for realistic sequences. These results are relevant to the adsorption of random heteropolymers and the wetting of disordered substrates.
The CyberKnife Robotic Radiosurgery System (Accuracy Incorporated, Sunnyvale, CA, USA) is used worldwide to treat tumors and neurological disorders anywhere in the body with sub-millimetre beam delivery accuracy. Accuracy has developed a number of new technologies in recent years to enhance the treatment of cancer patients. Such new technologies include a fast Monte Carlo Dose Calculation algorithm, Sequential Optimization dose planning, the IrisTM Variable Aperture Collimator, an 800 MU/min Linear Accelerator, and Optimized Path Traversal. These technologies enable physicists and physicians to plan treatments quickly and easily and deliver them with unrivalled accuracy and precision
The individuality of production devices should be taken into account when statistical models are designed for parallelized devices. In the present work, a new clustering method, referred to as NC-spectral clustering, is proposed for discriminating the individuality of production devices. The key idea is to classify samples according to the differences of the correlation among measured variables, since the individuality of production devices is expressed by the correlation. In the proposed NC-spectral clustering, the nearest correlation (NC) method and spectral clustering are integrated. The NC method generates the weighted graph that expresses the correlation-based similarities between samples, and the constructed graph is partitioned by spectral clustering. A new statistical process monit...
With the compensator-series equipment put into operation in 1992 - giving a performance of 330 Mvar - it was made possible for high-performance electronics to use a continuously variable, fully loaded power transmission line and to regulate the energy flow and minimise overcurrent losses. As well as these technical qualities, this system could offer environmental advantages for European implementation. This would avoid the need to plan and construct new high voltage transmission lines in order to meet increased demand. (orig.)
Continuum events represent an eminent source of background in any e+e- experiment. As these have a higher branching ratio than BB-bar events (at BaBar this ratio is estimated to about 3.5) or ?+?- events, efficient continuum background suppression is essential in many analyses. Using Artificial Neural Networks and the Nearest Neighbor Method we developed several selectors which, based only on the global event shape variables, efficiently tag BB-bar events and ?+?- events against the continuum background. These selectors could then be combined with the channel specific information in various types of analyses. The study was done using a parametric Monte Carlo.
Let Y be a nonnegative random variable with mean?? and finite positive variance ? 2, and let Y s , defined on the same space as Y, have the Y size-biased distribution, characterized by Formula Not Shown Under a variety of conditions on Y and the coupling of Y and Y s , including combinations of boundedness and monotonicity, one sided concentration of measure inequalities such as Formula Not Shown hold for some explicit A and B. The theorem is applied to the number of bulbs switched on at the terminal time in the so called lightbulb process of Rao et?al. (Sankhy? 69:137?161, 2007).
Mild steel samples were studied by chronoamperometry in sodium sulfide (Na[sub 2]S) aqueous solution. Pit nucleation and growth also were monitored by optical microscopy. The influence of variables such as temperature, polarization potential, surface roughness, the presence of electrochemically generated oxide layers, and the simultaneous presence of potassium hydroxide (KOH) was studied. The influence of each parameter on pit shape and growth was reviewed. Different reactions and competitive processes were proposed based on the experimental results.
This paper proposes an integrated method for using experimental data and CFD modeling to develop engineering correlations for atrium smoke management. Part I focused on the experimental program and validation of a CFD model of the experimental facility. Part II describes the extension of this model to a parametric study of balcony spill plumes. Smoke management in buildings during fire events often uses mechanical ventilation systems to maintain smoke layer elevation above a safe evacuation path. Design of these systems requires accurate correlations for the smoke production or mass flow rate of the buoyant fire plume. One design issue is the mass flow rate of fire plumes which spill out from a fire compartment, under a balcony and up through an atrium or other large volume. Current engineering correlations for these balcony spill plumes (BSPs) are based on a combination of one-tenth scale test data and theoretical analysis. The suitability of these correlations for real-scale designs ...
This paper proposes an integrated method for using experimental data and CFD modeling to develop engineering correlations for atrium smoke management. Part I focused on the experimental program and validation of a CFD model of the experimental facility. Part II describes the extension of this model to a parametric study of balcony spill plumes. Smoke management in buildings during fire events often uses mechanical ventilation systems to maintain smoke layer elevation above a safe evacuation path. Design of these systems requires accurate correlations for the smoke production or mass flow rate of the buoyant fire plume. One design issue is the mass flow rate of fire plumes which spill out from a fire compartment, under a balcony and up through an atrium or other large volume. Current engineering correlations for these balcony spill plumes (BSPs) are based on a combination of one-tenth scale test data and theoretical analysis. The suitability of these correlations for real-scale designs ...
Existing applications of Alloy 800 are summarized, with particular reference to its use in various types of reactor. The need for a co-ordinated research and development programme is stressed, and the variables to be explored are outlined. The papers relating to the problem of corrosion and cracking in water and steam are considered. the strength and ductility of Alloy 800 is considered. Finally, sections of the summary deal with the use of Alloy 800 for (a) sodium cooled fast reactor boiler tubes; (b) the high temperature gas cooled reactor; and (c) PWR steam generator tubes. (U.K.).
Asymptotic estimates for the typical number of irreducible coverings and the typical length of an irreducible covering of a Boolean matrix are obtained in the case when the number of rows is no less than the number of columns. As a consequence, asymptotic estimates are obtained for the typical number of maximal conjunctions and the typical rank of a maximal conjunction of a monotone Boolean function of variables defined by a conjunctive normal form of clauses. Similar estimates are given for the number of irredundant coverings and the length of an irredundant covering of an integer matrix (for the number of maximal conjunctions and the rank of a maximal conjunction of a two-valued logical function defined by its zero set). Results obtained previously in this area are overviewed.
The high-spin states in transitional odd-mass nuclei are studied in terms of an odd quasi-particle coupled to an asymmetric rotor with a variable moment of inertia (VMI). In order to take into account the VMI, the basis states are expanded in terms of the core eigenfunctions. Excitation energies, quadrupole moments, magnetic moments, B(E2) values and B(M1) values are calculated and compared with the experimental data for nuclei in Au and La regions. On comparison with other descriptions it is found that the treatment with VMI provides a more satisfactory explanation of the data. (Auth.).
This paper considers location?allocation problem in the real uncertain world and develops a possibilistic non-linear programming model to deal with this problem. Fuzzy decision making in fuzzy environment concept is used to determine possibility distribution of location and allocation variables. To solve this model, a novel approach based on genetic algorithm structure is developed. As the proposed model includes both deterministic (location) and uncertain (allocation) parameters, the developed solution algorithm uses a hybrid chromosome structure. Also, to cover continuous nature of the problem and prevent GA from early convergence, a new crossover operator is introduced. Finally, performance of the developed algorithm is evaluated by an example.
The emergence of bacterial antibiotic resistance is a growing problem, yet the variables that influence the rate of emergence of resistance are not well understood. In a microfluidic device designed to mimic naturally occurring bacterial niches, resistance of Escherichia coli to the antibiotic ciprofloxacin developed within 10 hours. Resistance emerged with as few as 100 bacteria in the initial inoculation. Whole-genome sequencing of the resistant organisms revealed that four functional single-nucleotide polymorphisms attained fixation. Knowledge about the rapid emergence of antibiotic resistance in the heterogeneous conditions within the mammalian body may be helpful in understanding the emergence of drug resistance during cancer chemotherapy. PMID:21940899
Diffusion of radon in a bed of activated charcoal is described by diffusion equations. An analytical solution of these equations is presented for the case of constant radon concentration in the atmosphere. The solutions are given separately for short term and long term exposure. An analytical form of the calibration constant f for long term exposure and constant radon concentration in air, was found. A numerical method and computer code based on the method of finite elements is developed for the case of variable radon concentration in air. This program simulates radon adsorption by the activated charcoal bed, enabling determination of sensitivity. The dependence of sensitivity on different parameters, such as temperature, thickness of the charcoal, etc. was studied using this program. (orig.) 10 refs.
A generalised procedure for quantifying the benefits of household biogas plants is presented. The sensitivity of the procedure to the uncertainty in input prices is reduced through the assumption of incremental benefits from the biogas plant. These benefits are quantified in terms of the quantity of fuelwood for which the biogas substitutes in cooking, the quantity of kerosene replaced through the use of biogas for lighting and the diesel fuel displaced through the use of a biogas fuelled dual-fuel engine for motive power. Sensitivity of the monetary benefits for these parameters is examined in order to identify variables which influence the viability of the technology to the end user. (author).
The A dependence of cumulative pion production yield cross sections on the basis of the comparison of the data on relative pion yields on Be,C,Al,Ti,Mo and W nuclei at the 159 deg angle laboratory system for the incident proton energy E_0 from 25 to 62 GeV is considered. The regular A dependence on cumulative variable X is noted. The results are compared with the data at E_0< 10 GeV. A possible interpretation of the observed behaviour on the basis of the hypothesis of the flucton mechanism of the pion production in the cumulative region is discussed. 15 refs.; 4 figs.
The Belinskii, Khalatnikov and Lifshitz conjecture \\cite{bkl1} posits that on approach to a space-like singularity in general relativity the dynamics are well approximated by `ignoring spatial derivatives in favor of time derivatives.' In \\cite{ahs1} we examined this idea from within a Hamiltonian framework and provided a new formulation of the conjecture in terms of variables well suited to loop quantum gravity. We now present the details of the analytical part of that investigation. While our motivation came from quantum considerations, thanks to some of its new features, our formulation should be useful also for future analytical and numerical investigations within general relativity.